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Abdel-Mannan O, Absoud M, Benetou C, Hickson H, Chong WK, Hemingway C, Lim M, Wright S, Hacohen Y. 085 Ten year follow-up surveillance of paediatric acquired demyelinating syndromes (ADS) in the UK. J Neurol Psychiatry 2022. [DOI: 10.1136/jnnp-2022-abn.410] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
ObjectiveTo describe 10-year follow-up of children <16 years with acquired demyelinating syndromes (ADS) from a UK-wide prospective surveillance study.MethodsDiagnoses were retrieved from the patients’ records via the patients’ paediatric or adult neurolo- gist using a questionnaire. Demyelinating phenotypes, at follow-up, were classified by expert review panel.Results24/125 (19.2%) children, identified in the original study, were diagnosed with multiple sclerosis (MS, incidence of 2.04/million children/year); 23/24 fulfilled 2017 McDonald criteria at onset. AQP4-Ab neuromy- elitis optica spectrum disorders were diagnosed in 2/125 (1.6%, 0.26/million children/year), and relapsing MOG-Ab associated disease in 5/125 (4%, 0.43/million children/year). 4/125 seronegative non-MS patients relapsed and 85/125 (68%) remained monophasic over 10 years. 5/125 (4%) originally diagnosed with ADS were reclassified during follow-up: three children diagnosed initially with acute disseminated encepha- lomyelitis were subsequently diagnosed with acute necrotising encephalopathy (RANBP2 mutation), primary hemophagocytic lymphohistiocytosis (Munc 13–4 gene inversion) and anti-NMDA-R encephalitis. One child initially diagnosed with optic neuritis was later diagnosed with vitamin B12 deficiency, and one presenting with transverse myelitis was subsequently diagnosed with Sjögren’s syndrome.ConclusionsThe majority of ADS presentations in children are monophasic even at 10-year follow. Given the implications for treatment strategies, MS and CNS autoantibody mimics warrant extensive investigations.o.abdel-mannan@ucl.ac.uk|NIHR Bursary
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Geva S, Jentschke S, Argyropoulos GPD, Chong WK, Gadian DG, Vargha-Khadem F. Volume reduction of caudate nucleus is associated with movement coordination deficits in patients with hippocampal atrophy due to perinatal hypoxia-ischaemia. Neuroimage Clin 2020; 28:102429. [PMID: 33010533 PMCID: PMC7530343 DOI: 10.1016/j.nicl.2020.102429] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2019] [Revised: 08/28/2020] [Accepted: 09/08/2020] [Indexed: 12/14/2022]
Abstract
Acute sentinel hypoxia-ischaemia in neonates can target the hippocampus, mammillary bodies, thalamus, and the basal ganglia. Our previous work with paediatric patients with a history of hypoxia-ischaemia has revealed hippocampal and diencephalic damage that impacts cognitive memory. However, the structural and functional status of other brain regions vulnerable to hypoxia-ischaemia, such as the basal ganglia, has not been investigated in these patients. Furthermore, it is not known whether there are any behavioural sequelae of such damage, especially in patients with no diagnosis of neurological disorder. Based on the established role of the basal ganglia and the thalamus in movement coordination, we studied manual motor function in 20 participants exposed to neonatal hypoxia-ischaemia, and a group of 17 healthy controls of comparable age. The patients' handwriting speed and accuracy was within the normal range (Detailed Assessment of Speed of Handwriting), and their movement adaptation learning (Rotary Pursuit task) was comparable to the control group's performance. However, as a group, patients showed an impairment in the Grooved Pegboard task and a trend for impairment in speed of movement while performing the Rotary Pursuit task, suggesting that some patients have subtle deficits in fine, complex hand movements. Voxel-based morphometry and volumetry showed bilateral reduction in grey matter volume of the thalamus and caudate nucleus. Reduced volumes in the caudate nucleus correlated across patients with performance on the Grooved Pegboard task. In summary, the fine movement coordination deficit affecting the hand and the wrist in patients exposed to early hypoxic-ischaemic brain injury may be related to reduced volumes of the caudate nucleus, and consistent with anecdotal parental reports of clumsiness and coordination difficulties in this cohort.
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Affiliation(s)
- Sharon Geva
- Cognitive Neuroscience and Neuropsychiatry Section, UCL Great Ormond Street Institute of Child Health, 30 Guilford Street, London WC1N 1EH, United Kingdom.
| | - Sebastian Jentschke
- Cognitive Neuroscience and Neuropsychiatry Section, UCL Great Ormond Street Institute of Child Health, 30 Guilford Street, London WC1N 1EH, United Kingdom.
| | - Georgios P D Argyropoulos
- Cognitive Neuroscience and Neuropsychiatry Section, UCL Great Ormond Street Institute of Child Health, 30 Guilford Street, London WC1N 1EH, United Kingdom.
| | - W K Chong
- Developmental Imaging and Biophysics Section, UCL Great Ormond Street Institute of Child Health, London WC1N 1EH, United Kingdom.
| | - David G Gadian
- Cognitive Neuroscience and Neuropsychiatry Section, UCL Great Ormond Street Institute of Child Health, 30 Guilford Street, London WC1N 1EH, United Kingdom.
| | - Faraneh Vargha-Khadem
- Cognitive Neuroscience and Neuropsychiatry Section, UCL Great Ormond Street Institute of Child Health, 30 Guilford Street, London WC1N 1EH, United Kingdom.
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Hong Z, Chong WK, Ng AYR, Li M, Ganguly R, Sum TC, Soo HS. Hydrophobic Metal Halide Perovskites for Visible‐Light Photoredox C−C Bond Cleavage and Dehydrogenation Catalysis. Angew Chem Int Ed Engl 2019. [DOI: 10.1002/ange.201812225] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- Zonghan Hong
- Division of Chemistry and Biological ChemistrySchool of Physical and Mathematical SciencesNanyang Technological University 21 Nanyang Link Singapore 637371 Singapore
| | - Wee Kiang Chong
- Division of Physics and Applied PhysicsSchool of Physical and Mathematical SciencesNanyang Technological University 21 Nanyang Link Singapore 637371 Singapore
| | - Andrew Yun Ru Ng
- Division of Chemistry and Biological ChemistrySchool of Physical and Mathematical SciencesNanyang Technological University 21 Nanyang Link Singapore 637371 Singapore
| | - Mingjie Li
- Division of Physics and Applied PhysicsSchool of Physical and Mathematical SciencesNanyang Technological University 21 Nanyang Link Singapore 637371 Singapore
| | - Rakesh Ganguly
- Division of Chemistry and Biological ChemistrySchool of Physical and Mathematical SciencesNanyang Technological University 21 Nanyang Link Singapore 637371 Singapore
| | - Tze Chien Sum
- Division of Physics and Applied PhysicsSchool of Physical and Mathematical SciencesNanyang Technological University 21 Nanyang Link Singapore 637371 Singapore
| | - Han Sen Soo
- Division of Chemistry and Biological ChemistrySchool of Physical and Mathematical SciencesNanyang Technological University 21 Nanyang Link Singapore 637371 Singapore
- Solar Fuels LaboratoryNanyang Technological University 50 Nanyang Avenue Singapore 639798 Singapore
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Hong Z, Chong WK, Ng AYR, Li M, Ganguly R, Sum TC, Soo HS. Hydrophobic Metal Halide Perovskites for Visible‐Light Photoredox C−C Bond Cleavage and Dehydrogenation Catalysis. Angew Chem Int Ed Engl 2019; 58:3456-3460. [DOI: 10.1002/anie.201812225] [Citation(s) in RCA: 62] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2018] [Indexed: 11/06/2022]
Affiliation(s)
- Zonghan Hong
- Division of Chemistry and Biological ChemistrySchool of Physical and Mathematical SciencesNanyang Technological University 21 Nanyang Link Singapore 637371 Singapore
| | - Wee Kiang Chong
- Division of Physics and Applied PhysicsSchool of Physical and Mathematical SciencesNanyang Technological University 21 Nanyang Link Singapore 637371 Singapore
| | - Andrew Yun Ru Ng
- Division of Chemistry and Biological ChemistrySchool of Physical and Mathematical SciencesNanyang Technological University 21 Nanyang Link Singapore 637371 Singapore
| | - Mingjie Li
- Division of Physics and Applied PhysicsSchool of Physical and Mathematical SciencesNanyang Technological University 21 Nanyang Link Singapore 637371 Singapore
| | - Rakesh Ganguly
- Division of Chemistry and Biological ChemistrySchool of Physical and Mathematical SciencesNanyang Technological University 21 Nanyang Link Singapore 637371 Singapore
| | - Tze Chien Sum
- Division of Physics and Applied PhysicsSchool of Physical and Mathematical SciencesNanyang Technological University 21 Nanyang Link Singapore 637371 Singapore
| | - Han Sen Soo
- Division of Chemistry and Biological ChemistrySchool of Physical and Mathematical SciencesNanyang Technological University 21 Nanyang Link Singapore 637371 Singapore
- Solar Fuels LaboratoryNanyang Technological University 50 Nanyang Avenue Singapore 639798 Singapore
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Yin T, Liu B, Yan J, Fang Y, Chen M, Chong WK, Jiang S, Kuo JL, Fang J, Liang P, Wei S, Loh KP, Sum TC, White TJ, Shen ZX. Pressure-Engineered Structural and Optical Properties of Two-Dimensional (C 4H 9NH 3) 2PbI 4 Perovskite Exfoliated nm-Thin Flakes. J Am Chem Soc 2018; 141:1235-1241. [PMID: 30561996 DOI: 10.1021/jacs.8b07765] [Citation(s) in RCA: 65] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Resolving the structure-property relationships of two-dimensional (2D) organic-inorganic hybrid perovskites is essential for the development of photovoltaic and photoelectronic devices. Here, pressure (0-10 GPa) was applied to 2D hybrid perovskite flakes mechanically exfoliated from butylammonium lead halide single crystals, (C4H9NH3)2PbI4, from which we observed a series of changes of the strong excitonic emissions in the photoluminescence spectra. By correlating with in situ high-pressure X-ray diffraction results, we examine successfully the relationship between structural modifications in the inorganic PbI42- layer and their excitonic properties. During the transition between Pbca (1b) phase and Pbca (1a) phase at around 0.1 GPa, the decrease in ⟨Pb-I-Pb⟩ bond angle and increase in Pb-I bond length lead to an abrupt blue shift of the excitonic bandgap. The presence of the P21/a phase above 1.4 GPa increases the ⟨Pb-I-Pb⟩ bond angle and decreases the Pb-I bond length, leading to a deep red shift of the excitonic bandgap. The total band gap narrowing of ∼350 meV to 2.03 eV at 5.3 GPa before amorphization, facilitates (C4H9NH3)2PbI4 as a much better solar absorber. Moreover, phase transitions inevitably modify the carrier lifetime of (C4H9NH3)2PbI4, where an initial 150 ps at ambient phase is prolongated to 190 ps in the Pbca (1a) phase along with enhanced photoluminescence (PL), originating from pressure-induced strong radiative recombination of trapped excitons.The onset of P21/a phase shortens significantly the carrier lifetime to 53 ps along with a weak PL emission due to pressure-induced severe lattice distortion and amorphization. High-pressure study on (C4H9NH3)2PbI4 nm-thin flakes may provide insights into the mechanisms for synthetically designing novel 2D hybrid perovskite based photoelectronic devices and solar cells.
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Affiliation(s)
- Tingting Yin
- Centre for Disruptive Photonic Technologies, School of Physical and Mathematical Sciences , Nanyang Technological University 637371 , Singapore
| | - Bo Liu
- Department of Chemistry and Centre for Advanced 2D Materials (CA2DM) , 3 Science Drive 3 117543 , Singapore.,Division of Physics and Applied Physics , School of Physical and Mathematical Sciences (SPMS) , NTU, 21 Nanyang Link 637371 , Singapore
| | - Jiaxu Yan
- Key Laboratory of Flexible Electronics (KLOFE) & Institute of Advanced Materials (IAM), Jiangsu National Synergistic Innovation Center for Advanced Materials (SICAM) , Nanjing Tech University (Nanjing Tech) , 30 South Puzhu Road , Nanjing 211816 , P. R. China.,Division of Physics and Applied Physics , School of Physical and Mathematical Sciences (SPMS) , NTU, 21 Nanyang Link 637371 , Singapore
| | - Yanan Fang
- ERI@N , Research Techno Plaza , X-Frontier Block, Level 5, 50 Nanyang Drive 637553 , Singapore
| | - Minghua Chen
- Key Laboratory of Engineering Dielectric and Applications (Ministry of Education) , Harbin University of Science and Technology , Harbin 150080 , P. R. China
| | - Wee Kiang Chong
- Division of Physics and Applied Physics , School of Physical and Mathematical Sciences (SPMS) , NTU, 21 Nanyang Link 637371 , Singapore.,Energy Research Institute @ NTU, ERI@N, Interdisciplinary Graduate School , Nanyang Technological University 639798 , Singapore
| | - Shaojie Jiang
- Materials Science and Engineering Program , State University of New York at Binghamton Binghamton , New York 13902 , United States
| | - Jer-Lai Kuo
- Institute of Atomic and Molecular Sciences , Academia Sinica , Taipei 10617 , Taiwan
| | - Jiye Fang
- Materials Science and Engineering Program , State University of New York at Binghamton Binghamton , New York 13902 , United States
| | - Pei Liang
- College of Optical and Electronic Technology , China Jiliang University , 310018 Hangzhou , China
| | - Shuhuai Wei
- Beijing Computational Science Research Center , 100094 Beijing , China
| | - Kian Ping Loh
- Department of Chemistry and Centre for Advanced 2D Materials (CA2DM) , 3 Science Drive 3 117543 , Singapore
| | - Tze Chien Sum
- Division of Physics and Applied Physics , School of Physical and Mathematical Sciences (SPMS) , NTU, 21 Nanyang Link 637371 , Singapore
| | - Timothy J White
- ERI@N , Research Techno Plaza , X-Frontier Block, Level 5, 50 Nanyang Drive 637553 , Singapore
| | - Ze Xiang Shen
- Centre for Disruptive Photonic Technologies, School of Physical and Mathematical Sciences , Nanyang Technological University 637371 , Singapore.,Division of Physics and Applied Physics , School of Physical and Mathematical Sciences (SPMS) , NTU, 21 Nanyang Link 637371 , Singapore
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Giovanni D, Chong WK, Liu YYF, Dewi HA, Yin T, Lekina Y, Shen ZX, Mathews N, Gan CK, Sum TC. Coherent Spin and Quasiparticle Dynamics in Solution-Processed Layered 2D Lead Halide Perovskites. Adv Sci (Weinh) 2018; 5:1800664. [PMID: 30356921 PMCID: PMC6193146 DOI: 10.1002/advs.201800664] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2018] [Revised: 06/23/2018] [Indexed: 05/13/2023]
Abstract
Layered 2D halide perovskites with their alternating organic and inorganic atomic layers that form a self-assembled quantum well system are analogues of the purely inorganic 2D transition metal dichalcogenides. Within their periodic structures lie a hotbed of photophysical phenomena such as dielectric confinement effect, optical Stark effect, strong exciton-photon coupling, etc. Detailed understanding into the strong light-matter interactions in these hybrid organic-inorganic semiconductor systems remains modest. Herein, the intricate coherent interplay of exciton, spin, and phonon dynamics in (C6H5C2H4NH3)2PbI4 thin films using transient optical spectroscopy is explicated. New insights into the hotly debated origins of transient spectral features, relaxation pathways, ultrafast spin relaxation via exchange interaction, and strong coherent exciton-phonon coupling are revealed from the detailed phenomenological modeling. Importantly, this work unravels the complex interplay of spin-quasiparticle interactions in these layered 2D halide perovskites with large spin-orbit coupling.
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Affiliation(s)
- David Giovanni
- Energy Research Institute @ NTUERI@NInterdisciplinary Graduate SchoolNanyang Technological University50 Nanyang Avenue, Block S2‐B3a‐01Singapore639798Singapore
- Division of Physics and Applied PhysicsSchool of Physical and Mathematical SciencesNanyang Technological University21 Nanyang LinkSingapore637371
| | - Wee Kiang Chong
- Energy Research Institute @ NTUERI@NInterdisciplinary Graduate SchoolNanyang Technological University50 Nanyang Avenue, Block S2‐B3a‐01Singapore639798Singapore
- Division of Physics and Applied PhysicsSchool of Physical and Mathematical SciencesNanyang Technological University21 Nanyang LinkSingapore637371
| | - Yu Yang Fredrik Liu
- Institute of High Performance Computing1 Fusionopolis Way, #16‐16 ConnexisSingapore138632
- Theory of Condensed Matter GroupCavendish LaboratoryJJ Thomson AvenueCambridgeCB3 0HEUK
| | - Herlina Arianita Dewi
- Energy Research Institute @NTU (ERI@N)Research Techno Plaza, X‐Frontier Block, Level 5, 50 Nanyang DriveSingapore637553
| | - Tingting Yin
- Division of Physics and Applied PhysicsSchool of Physical and Mathematical SciencesNanyang Technological University21 Nanyang LinkSingapore637371
| | - Yulia Lekina
- Division of Physics and Applied PhysicsSchool of Physical and Mathematical SciencesNanyang Technological University21 Nanyang LinkSingapore637371
| | - Ze Xiang Shen
- Energy Research Institute @ NTUERI@NInterdisciplinary Graduate SchoolNanyang Technological University50 Nanyang Avenue, Block S2‐B3a‐01Singapore639798Singapore
- Division of Physics and Applied PhysicsSchool of Physical and Mathematical SciencesNanyang Technological University21 Nanyang LinkSingapore637371
| | - Nripan Mathews
- Energy Research Institute @NTU (ERI@N)Research Techno Plaza, X‐Frontier Block, Level 5, 50 Nanyang DriveSingapore637553
- School of Materials Science and EngineeringNanyang Technological UniversityNanyang AvenueSingapore639798
| | - Chee Kwan Gan
- Institute of High Performance Computing1 Fusionopolis Way, #16‐16 ConnexisSingapore138632
| | - Tze Chien Sum
- Energy Research Institute @ NTUERI@NInterdisciplinary Graduate SchoolNanyang Technological University50 Nanyang Avenue, Block S2‐B3a‐01Singapore639798Singapore
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Warne RR, Carney OM, Wang G, Bhattacharya D, Chong WK, Aylett SE, Mankad K. The Bone Does Not Predict the Brain in Sturge-Weber Syndrome. AJNR Am J Neuroradiol 2018; 39:1543-1549. [PMID: 30026385 DOI: 10.3174/ajnr.a5722] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2018] [Accepted: 05/18/2018] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE It has been hypothesized that skull marrow signal alteration may represent an early disease manifestation of Sturge-Weber syndrome before development of its intracranial manifestations. We alternatively hypothesized that intraosseous changes are associated with the overlying port-wine stain rather than the intracranial stigmata of Sturge-Weber syndrome and hence are not a predictor of brain involvement. MATERIALS AND METHODS MR imaging of children presenting with port-wine stain and/or Sturge-Weber syndrome between 1998 and 2017 was evaluated by 2 pediatric neuroradiologists for marrow signal abnormality and pial angioma and other Sturge-Weber syndrome features: ocular hemangioma, atrophy, and white matter changes (advanced myelination). Groups were divided into port-wine stain-only (without intracranial Sturge-Weber syndrome features) and Sturge-Weber syndrome (the presence of cerebral pial angioma). The χ2 test was performed to evaluate the association between port-wine stain and bone marrow changes and between osseous change and pial angioma. RESULTS We reviewed 139 cases: 40 with port-wine stain-only and 99 with Sturge-Weber syndrome with pial angioma. Fifteen of 99 cases of Sturge-Weber syndrome had no port-wine stain. In the port-wine stain-only cohort, 78% had ipsilateral bony changes and 17% had no intraosseous changes. In the Sturge-Weber syndrome cohort, 84/99 had associated port-wine stain, 91% (P < .01) had bony changes ipsilateral to the port-wine stain or had no bone changes in the absence of port-wine stain, and 77% (P = .27) had bony changes ipsilateral to a cerebral pial angioma. Eighty percent of patients with Sturge-Weber syndrome who lacked a port-wine stain also lacked marrow changes. Five patients with bilateral port-wine stain and bilateral marrow changes had only a unilateral pial angioma. CONCLUSIONS Intraosseous marrow changes are strongly associated with facial port-wine stain; no significant association was found between pial angioma and bone marrow changes.
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Affiliation(s)
- R R Warne
- From the Department of Paediatric Neuroradiology (R.R.W., O.M.C., D.B., W.K.C., K.M.), Great Ormond Street Hospital for Children, NHS Foundation Trust, London, UK
| | - O M Carney
- From the Department of Paediatric Neuroradiology (R.R.W., O.M.C., D.B., W.K.C., K.M.), Great Ormond Street Hospital for Children, NHS Foundation Trust, London, UK
| | - G Wang
- Department of Biostatistics (G.W.), University of Sydney School of Public Health, Sydney, New South Wales, Australia 2006
| | - D Bhattacharya
- From the Department of Paediatric Neuroradiology (R.R.W., O.M.C., D.B., W.K.C., K.M.), Great Ormond Street Hospital for Children, NHS Foundation Trust, London, UK
| | - W K Chong
- From the Department of Paediatric Neuroradiology (R.R.W., O.M.C., D.B., W.K.C., K.M.), Great Ormond Street Hospital for Children, NHS Foundation Trust, London, UK
| | - S E Aylett
- Neurosciences (S.E.A.), Great Ormond Street Hospital for Children and Developmental Neurosciences University College London, NHS Foundation Trust, London UK
| | - K Mankad
- From the Department of Paediatric Neuroradiology (R.R.W., O.M.C., D.B., W.K.C., K.M.), Great Ormond Street Hospital for Children, NHS Foundation Trust, London, UK
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Hu Y, Zhang H, Chong WK, Li Y, Ke Y, Ganguly R, Morris SA, You L, Yu T, Sum TC, Long Y, Fan HJ. Molecular Engineering toward Coexistence of Dielectric and Optical Switch Behavior in Hybrid Perovskite Phase Transition Material. J Phys Chem A 2018; 122:6416-6423. [DOI: 10.1021/acs.jpca.8b05693] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Yuzhong Hu
- School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371
| | - Hongbo Zhang
- School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371
| | - Wee Kiang Chong
- School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371
| | - Yongxin Li
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore 637371
| | - Yujie Ke
- School of Materials Science and Engineering, Nanyang Technological University, Singapore 639798
| | - Rakesh Ganguly
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore 637371
| | - Samuel Alexander Morris
- Facility for Analysis, Characterisation, Testing and Simulation (FACT), Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798
| | - Lu You
- School of Materials Science and Engineering, Nanyang Technological University, Singapore 639798
| | - Ting Yu
- School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371
| | - Tze Chien Sum
- School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371
| | - Yi Long
- School of Materials Science and Engineering, Nanyang Technological University, Singapore 639798
| | - Hong Jin Fan
- School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore 637371
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Yin T, Fang Y, Chong WK, Ming KT, Jiang S, Li X, Kuo JL, Fang J, Sum TC, White TJ, Yan J, Shen ZX. High-Pressure-Induced Comminution and Recrystallization of CH 3 NH 3 PbBr 3 Nanocrystals as Large Thin Nanoplates. Adv Mater 2018; 30:1705017. [PMID: 29178658 DOI: 10.1002/adma.201705017] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2017] [Revised: 09/25/2017] [Indexed: 06/07/2023]
Abstract
High pressure (HP) can drive the direct sintering of nanoparticle assemblies for Ag/Au, CdSe/PbS nanocrystals (NCs). Instead of direct sintering for the conventional nanocrystals, this study experimentally observes for the first time high-pressure-induced comminution and recrystallization of organic-inorganic hybrid perovskite nanocrystals into highly luminescent nanoplates with a shorter carrier lifetime. Such novel pressure response is attributed to the unique structural nature of hybrid perovskites under high pressure: during the drastic cubic-orthorhombic structural transformation at ≈2 GPa, (301) the crystal plane fully occupied by organic molecules possesses a higher surface energy, triggering the comminution of nanocrystals into nanoslices along such crystal plane. Beyond bulk perovskites, in which pressure-induced modifications on crystal structures and functional properties will disappear after pressure release, the pressure-formed variants, i.e., large (≈100 nm) and thin (<10 nm) perovskite nanoplates, are retained and these exhibit simultaneous photoluminescence emission enhancing (a 15-fold enhancement in the photoluminescence) and carrier lifetime shortening (from ≈18.3 ± 0.8 to ≈7.6 ± 0.5 ns) after releasing of pressure from 11 GPa. This pressure-induced comminution of hybrid perovskite NCs and a subsequent amorphization-recrystallization treatment offer the possibilities of engineering the advanced hybrid perovskites with specific properties.
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Affiliation(s)
- Tingting Yin
- Centre for Disruptive Photonic Technologies, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore, 637371
| | - Yanan Fang
- School of Materials Science and Engineering, Nanyang Technological University, Singapore, 639798
| | - Wee Kiang Chong
- Energy Research Institute @ NTU, ERI@N, Interdisciplinary Graduate School, Nanyang Technological University, Singapore, 639798
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences (SPMS), Nanyang Technological University, 21 Nanyang Link, Singapore, 637371
| | - Koh Teck Ming
- ERI@N, Research Techno Plaza, X-Frontier Block, Level 5, 50 Nanyang Drive, Singapore, 637553
| | - Shaojie Jiang
- Materials Science and Engineering Program State University of New York at Binghamton Binghamton, NY, 13902, USA
| | - Xianglin Li
- School of Materials Science and Engineering, Nanyang Technological University, Singapore, 639798
| | - Jer-Lai Kuo
- Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei, 10617, Taiwan
| | - Jiye Fang
- Materials Science and Engineering Program State University of New York at Binghamton Binghamton, NY, 13902, USA
| | - Tze Chien Sum
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences (SPMS), Nanyang Technological University, 21 Nanyang Link, Singapore, 637371
| | - Timothy J White
- School of Materials Science and Engineering, Nanyang Technological University, Singapore, 639798
| | - Jiaxu Yan
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences (SPMS), Nanyang Technological University, 21 Nanyang Link, Singapore, 637371
- Key Laboratory of Flexible Electronics (KLOFE) & Institute of Advanced Materials (IAM), Jiangsu National Synergistic Innovation Center for Advanced Materials (SICAM), Nanjing Tech University (Nanjing Tech), 30 South Puzhu Road, Nanjing, 211816, P. R. China
| | - Ze Xiang Shen
- Centre for Disruptive Photonic Technologies, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore, 637371
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences (SPMS), Nanyang Technological University, 21 Nanyang Link, Singapore, 637371
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Ware N, Sebire NJ, Chong WK, Krishnan R, Marks SD. When is biopsy-proven TIN not simply TIN? Answers. Pediatr Nephrol 2017; 32:977-979. [PMID: 27718088 DOI: 10.1007/s00467-016-3478-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/21/2016] [Revised: 07/08/2016] [Accepted: 07/12/2016] [Indexed: 11/29/2022]
Affiliation(s)
- Nicholas Ware
- Department of Paediatric Nephrology, Great Ormond Street Hospital, Great Ormond Street Hospital for Children NHS Foundation Trust, London, WC1N 3JH, UK.
| | - Neil J Sebire
- Department of Paediatric Nephrology, Great Ormond Street Hospital, Great Ormond Street Hospital for Children NHS Foundation Trust, London, WC1N 3JH, UK
| | - W K Chong
- Department of Paediatric Nephrology, Great Ormond Street Hospital, Great Ormond Street Hospital for Children NHS Foundation Trust, London, WC1N 3JH, UK
| | - Rajesh Krishnan
- Department of Paediatric Nephrology, University Hospitals of Wales, CF14 4XW , Cardiff, UK
| | - Stephen D Marks
- Department of Paediatric Nephrology, Great Ormond Street Hospital, Great Ormond Street Hospital for Children NHS Foundation Trust, London, WC1N 3JH, UK
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11
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Forde KM, Glover MT, Chong WK, Kinsler VA. Segmental hemangioma of the head and neck: High prevalence of PHACE syndrome. J Am Acad Dermatol 2017; 76:356-358. [PMID: 28089002 DOI: 10.1016/j.jaad.2016.06.058] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2016] [Revised: 06/20/2016] [Accepted: 06/29/2016] [Indexed: 11/30/2022]
Affiliation(s)
- Karina M Forde
- Paediatric Dermatology, Great Ormond Street Hospital for Children, London
| | - Mary T Glover
- Paediatric Dermatology, Great Ormond Street Hospital for Children, London
| | - W K Chong
- Paediatric Dermatology, Great Ormond Street Hospital for Children, London
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12
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Kinsler VA, O'Hare P, Bulstrode N, Calonje JE, Chong WK, Hargrave D, Jacques T, Lomas D, Sebire NJ, Slater O. Melanoma in congenital melanocytic naevi. Br J Dermatol 2017; 176:1131-1143. [PMID: 28078671 PMCID: PMC5484991 DOI: 10.1111/bjd.15301] [Citation(s) in RCA: 116] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/22/2016] [Indexed: 01/31/2023]
Abstract
Congenital melanocytic naevi (CMN) are a known risk factor for melanoma, with the greatest risk currently thought to be in childhood. There has been controversy over the years about the incidence of melanoma, and therefore over the clinical management of CMN, due partly to the difficulties of histological diagnosis and partly to publishing bias towards cases of malignancy. Large cohort studies have demonstrated that melanoma risk in childhood is related to the severity of the congenital phenotype. New understanding of the genetics of CMN offers the possibility of improvement in diagnosis of melanoma, identification of those at highest risk, and new treatment options. We review the world literature and our centre's experience over the last 25 years, including the molecular characteristics of melanoma in these patients and new melanoma incidence and outcome data from our prospective cohort. Management strategies are proposed for presentation of suspected melanoma of the skin and the central nervous system in patients with CMN, including use of oral mitogen-activated protein kinase kinase inhibitors in NRAS-mutated tumours.
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Affiliation(s)
- V A Kinsler
- Paediatric Dermatology, Great Ormond Street Hospital for Children NHS Foundation Trust, London, U.K.,Genetics and Genomic Medicine, UCL Institute of Child Health, London, U.K
| | - P O'Hare
- Paediatric Oncology, Great Ormond Street Hospital for Children NHS Foundation Trust, London, U.K
| | - N Bulstrode
- Paediatric Plastic Surgery, Great Ormond Street Hospital for Children NHS Foundation Trust, London, U.K
| | - J E Calonje
- Dermatopathology Department, St John's Institute of Dermatology, Guy's and St Thomas' Hospital, London, U.K
| | - W K Chong
- Paediatric Neuroradiology, Great Ormond Street Hospital for Children NHS Foundation Trust, London, U.K
| | - D Hargrave
- Paediatric Oncology, Great Ormond Street Hospital for Children NHS Foundation Trust, London, U.K.,Developmental Biology and Cancer Programme, UCL Institute of Child Health, London, U.K
| | - T Jacques
- Histopathology, Great Ormond Street Hospital for Children NHS Foundation Trust, London, U.K.,Developmental Biology and Cancer Programme, UCL Institute of Child Health, London, U.K
| | - D Lomas
- Paediatric Dermatology, Great Ormond Street Hospital for Children NHS Foundation Trust, London, U.K
| | - N J Sebire
- Histopathology, Great Ormond Street Hospital for Children NHS Foundation Trust, London, U.K.,Developmental Biology and Cancer Programme, UCL Institute of Child Health, London, U.K
| | - O Slater
- Paediatric Oncology, Great Ormond Street Hospital for Children NHS Foundation Trust, London, U.K
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13
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Abstract
This study aimed to evaluate cerebral magnetic resonance imaging (MRI) scans of children with prenatal drug exposure in a clinical context. A hospital-based cohort of 10- to 14-year-old children, prenatally exposed to alcohol, opioids, and polysubstances, and a group of sex- and age-matched controls were examined with cerebral MRI. Scans obtained from 34 exposed children and 40 controls were scored based on the presence and degree of pathology by an experienced pediatric neuroradiologist blinded to the participants' background. Overall visual detectable MRI pathology was found in 35% of the exposed children and 33% of the controls (odds ratio = 1.08; 95% confidence interval = 0.36-3.25). No specific imaging pattern following prenatal drug exposure was seen by the means of simple visual analysis of cerebral MRI scans. Although cerebral MRI is feasible, it is probably of limited value in the clinical assessment of children with prenatal drug exposure.
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Affiliation(s)
- Eivind Sirnes
- 1 Haukeland University Hospital, Bergen, Norway.,2 University of Bergen, Bergen, Norway
| | - Irene B Elgen
- 1 Haukeland University Hospital, Bergen, Norway.,2 University of Bergen, Bergen, Norway
| | - W K Chong
- 3 Great Ormond Street Hospital for Children, London, UK
| | | | - Stein Magnus Aukland
- 1 Haukeland University Hospital, Bergen, Norway.,2 University of Bergen, Bergen, Norway
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14
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Darin N, Reid E, Prunetti L, Samuelsson L, Husain RA, Wilson M, El Yacoubi B, Footitt E, Chong WK, Wilson LC, Prunty H, Pope S, Heales S, Lascelles K, Champion M, Wassmer E, Veggiotti P, de Crécy-Lagard V, Mills PB, Clayton PT. Mutations in PROSC Disrupt Cellular Pyridoxal Phosphate Homeostasis and Cause Vitamin-B 6-Dependent Epilepsy. Am J Hum Genet 2016; 99:1325-1337. [PMID: 27912044 DOI: 10.1016/j.ajhg.2016.10.011] [Citation(s) in RCA: 98] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2016] [Accepted: 10/25/2016] [Indexed: 12/29/2022] Open
Abstract
Pyridoxal 5'-phosphate (PLP), the active form of vitamin B6, functions as a cofactor in humans for more than 140 enzymes, many of which are involved in neurotransmitter synthesis and degradation. A deficiency of PLP can present, therefore, as seizures and other symptoms that are treatable with PLP and/or pyridoxine. Deficiency of PLP in the brain can be caused by inborn errors affecting B6 vitamer metabolism or by inactivation of PLP, which can occur when compounds accumulate as a result of inborn errors of other pathways or when small molecules are ingested. Whole-exome sequencing of two children from a consanguineous family with pyridoxine-dependent epilepsy revealed a homozygous nonsense mutation in proline synthetase co-transcribed homolog (bacterial), PROSC, which encodes a PLP-binding protein of hitherto unknown function. Subsequent sequencing of 29 unrelated indivduals with pyridoxine-responsive epilepsy identified four additional children with biallelic PROSC mutations. Pre-treatment cerebrospinal fluid samples showed low PLP concentrations and evidence of reduced activity of PLP-dependent enzymes. However, cultured fibroblasts showed excessive PLP accumulation. An E.coli mutant lacking the PROSC homolog (ΔYggS) is pyridoxine sensitive; complementation with human PROSC restored growth whereas hPROSC encoding p.Leu175Pro, p.Arg241Gln, and p.Ser78Ter did not. PLP, a highly reactive aldehyde, poses a problem for cells, which is how to supply enough PLP for apoenzymes while maintaining free PLP concentrations low enough to avoid unwanted reactions with other important cellular nucleophiles. Although the mechanism involved is not fully understood, our studies suggest that PROSC is involved in intracellular homeostatic regulation of PLP, supplying this cofactor to apoenzymes while minimizing any toxic side reactions.
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Affiliation(s)
- Niklas Darin
- Department of Pediatrics, University of Gothenburg and Sahlgrenska University Hospital, 41685 Gothenburg, Sweden
| | - Emma Reid
- Genetics and Genomic Medicine, UCL Institute of Child Health, London WC1N 1EH, UK
| | - Laurence Prunetti
- Department of Microbiology and Cell Science, Institute for Food and Agricultural Sciences and Genetic Institute, University of Florida, Gainesville, FL 32611, USA
| | - Lena Samuelsson
- Department of Clinical Genetics, Sahlgrenska University Hospital, 413 45 Gothenburg, Sweden
| | - Ralf A Husain
- Centre for Inborn Metabolic Disorders, Department of Neuropediatrics, Jena University Hospital, 07740 Jena, Germany
| | - Matthew Wilson
- Genetics and Genomic Medicine, UCL Institute of Child Health, London WC1N 1EH, UK
| | - Basma El Yacoubi
- Department of Microbiology and Cell Science, Institute for Food and Agricultural Sciences and Genetic Institute, University of Florida, Gainesville, FL 32611, USA
| | - Emma Footitt
- Department of Metabolic Medicine, Great Ormond Street Hospital NHS Foundation Trust, London WC1N 3JH, UK
| | - W K Chong
- Department of Radiology, Great Ormond Street Hospital NHS Foundation Trust, London WC1N 3JH, UK
| | - Louise C Wilson
- Department of Clinical Genetics, Great Ormond Street Hospital NHS Foundation Trust, London WC1N 3JH, UK
| | - Helen Prunty
- Department of Chemical Pathology, Great Ormond Street Hospital NHS Foundation Trust, London WC1N 3JH, UK
| | - Simon Pope
- Neurometabolic Unit, National Hospital, Queen Square, London WC1N 3BG, UK
| | - Simon Heales
- Genetics and Genomic Medicine, UCL Institute of Child Health, London WC1N 1EH, UK; Department of Chemical Pathology, Great Ormond Street Hospital NHS Foundation Trust, London WC1N 3JH, UK; Neurometabolic Unit, National Hospital, Queen Square, London WC1N 3BG, UK
| | - Karine Lascelles
- Department of Neuroscience, Evelina London Children's Hospital, St Thomas' Hospital, Westminster Bridge Road, London SE1 7EH, UK
| | - Mike Champion
- Department of Inherited Metabolic Disease, Evelina London Children's Hospital, St Thomas' Hospital, Westminster Bridge Road, London SE1 7EH, UK
| | | | - Pierangelo Veggiotti
- Department of Child Neurology and Psychiatry, C. Mondino National Neurological Institute, Mondino 2, 27100 Pavia, Italy; Brain and Behaviour Department, University of Pavia, Strada Nuova, 65 Pavia, Italy
| | - Valérie de Crécy-Lagard
- Department of Microbiology and Cell Science, Institute for Food and Agricultural Sciences and Genetic Institute, University of Florida, Gainesville, FL 32611, USA
| | - Philippa B Mills
- Genetics and Genomic Medicine, UCL Institute of Child Health, London WC1N 1EH, UK.
| | - Peter T Clayton
- Genetics and Genomic Medicine, UCL Institute of Child Health, London WC1N 1EH, UK.
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15
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Iro MA, Sadarangani M, Absoud M, Chong WK, Clark CA, Easton A, Gray V, Kneen R, Lim M, Pike M, Solomon T, Vincent A, Willis L, Yu LM, Pollard AJ. ImmunoglobuliN in the Treatment of Encephalitis (IgNiTE): protocol for a multicentre randomised controlled trial. BMJ Open 2016; 6:e012356. [PMID: 27810972 PMCID: PMC5129051 DOI: 10.1136/bmjopen-2016-012356] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
INTRODUCTION Infectious and immune-mediated encephalitides are important but under-recognised causes of morbidity and mortality in childhood, with a 7% death rate and up to 50% morbidity after prolonged follow-up. There is a theoretical basis for ameliorating the immune response with intravenous immunoglobulin (IVIG), which is supported by empirical evidence of a beneficial response following its use in the treatment of viral and autoimmune encephalitis. In immune-mediated encephalitis, IVIG is often used after a delay (by weeks in some cases), while diagnosis is confirmed. Wider use of IVIG in infectious encephalitis and earlier use in immune-mediated encephalitis could improve outcomes for these conditions. We describe the protocol for the first ever randomised control trial of IVIG treatment for children with all-cause encephalitis. METHODS AND ANALYSIS 308 children (6 months to 16 years) with a diagnosis of acute/subacute encephalitis will be recruited in ∼30 UK hospitals and randomised to receive 2 doses (1 g/kg/dose) of either IVIG or matching placebo, in addition to standard treatment. Recruitment will be over a 42-month period and follow-up of each participant will be for 12 months post randomisation. The primary outcome is 'good recovery' (score of 2 or lower on the Glasgow Outcome Score Extended-paediatric version), at 12 months after randomisation. Additional secondary neurological measures will be collected at 4-6 weeks after discharge from acute care and at 6 and 12 months after randomisation. Safety, radiological, other autoimmune and tertiary outcomes will also be assessed. ETHICS AND DISSEMINATION This trial has been approved by the UK National Research Ethics committee (South Central-Oxford A; REC 14/SC/1416). Current protocol: V4.0 (10/03/2016). The findings will be presented at national and international meetings and conferences and published in peer-reviewed journals. TRIAL REGISTRATION NUMBERS NCT02308982, EudraCT201400299735 and ISRCTN15791925; Pre-results.
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Affiliation(s)
- M A Iro
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford and NIHR Biomedical Research Centre, Oxford University Hospitals NHS Foundation Trust, Oxford, UK
| | - M Sadarangani
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford and NIHR Biomedical Research Centre, Oxford University Hospitals NHS Foundation Trust, Oxford, UK
- Department of Paediatrics, Oxford University Hospitals NHS Foundation Trust, Oxford, UK
- Vaccine Evaluation Center, BC Children's Hospital Research Institute, University of British Columbia, Vancouver BC, Canada
| | - M Absoud
- Department of Children's Neurosciences, Evelina London Children's Hospital at Guy's and St Thomas’ NHS Foundation Trust, King's Health Partners Academic Health Science Centre, London, UK
| | - W K Chong
- Department of Radiology, Great Ormond Street Hospital for Children, London, UK
| | - C A Clark
- Institute of Child Health, University College London, London, UK
| | - A Easton
- The Encephalitis Society, Malton, North Yorkshire, UK
| | - V Gray
- Psychological services (Paediatrics), Alder Hey Children's NHS Foundation Trust, Liverpool, UK
| | - R Kneen
- Institute of Infection and Global Health, University of Liverpool, Liverpool, UK
- Littlewoods Neuroscience Foundation, Department of Neurology, Alder Hey Children's NHS Foundation Trust, Liverpool, UK
| | - M Lim
- Department of Children's Neurosciences, Evelina London Children's Hospital at Guy's and St Thomas’ NHS Foundation Trust, King's Health Partners Academic Health Science Centre, London, UK
| | - M Pike
- Department of Paediatric Neurology, Oxford University Hospitals NHS Trust, Oxford, UK
| | - T Solomon
- Institute of Infection and Global Health, University of Liverpool, Liverpool, UK
- National Institute for Health Research Health Protection Research Unit in Emerging and Zoonotic Infections, University of Liverpool, Liverpool, UK
- Walton Centre NHS Foundation Trust, Liverpool, UK
| | - A Vincent
- Department of Clinical Neurosciences, Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, UK
| | - L Willis
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford and NIHR Biomedical Research Centre, Oxford University Hospitals NHS Foundation Trust, Oxford, UK
| | - L-M Yu
- Nuffield Department of Primary Care Health Sciences, University of Oxford, Oxford, UK
| | - A J Pollard
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford and NIHR Biomedical Research Centre, Oxford University Hospitals NHS Foundation Trust, Oxford, UK
- Department of Paediatrics, Oxford University Hospitals NHS Foundation Trust, Oxford, UK
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16
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Xing G, Kumar MH, Chong WK, Liu X, Cai Y, Ding H, Asta M, Grätzel M, Mhaisalkar S, Mathews N, Sum TC. Solution-Processed Tin-Based Perovskite for Near-Infrared Lasing. Adv Mater 2016; 28:8191-8196. [PMID: 27417520 DOI: 10.1002/adma.201601418] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2016] [Revised: 05/24/2016] [Indexed: 05/19/2023]
Abstract
The family of solution-processed tin-based perovskites is demonstrated as a new and superior near-infrared gain medium. Due to the large electron-hole bimolecular recombination associated with tin and the reduced trap density with SnF2 treatment, these lead-free "green" perovskites yield stable coherent light emission extending to ≈1 μm at strikingly low thresholds.
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Affiliation(s)
- Guichuan Xing
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore 637371, Singapore
| | - Mulmudi Hemant Kumar
- Energy Research Institute @NTU (ERI@N), Research Techno Plaza, X-Frontier Block, Level 5, 50 Nanyang Drive, Singapore, 637553, Singapore
- School of Materials Science and Engineering, Nanyang Technological University, Nanyang Avenue, Singapore, 639798, Singapore
| | - Wee Kiang Chong
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore 637371, Singapore
| | - Xinfeng Liu
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore 637371, Singapore
| | - Yao Cai
- Department of Materials Science and Engineering, University of California, Berkeley, CA, 94720, USA
| | - Hong Ding
- Department of Materials Science and Engineering, University of California, Berkeley, CA, 94720, USA
| | - Mark Asta
- Department of Materials Science and Engineering, University of California, Berkeley, CA, 94720, USA
| | - Michael Grätzel
- Energy Research Institute @NTU (ERI@N), Research Techno Plaza, X-Frontier Block, Level 5, 50 Nanyang Drive, Singapore, 637553, Singapore
- Laboratory of Photonics and Interfaces, Department of Chemistry and Chemical Engineering, Swiss Federal Institute of Technology, Station 6, CH-1015 Lausanne, Switzerland
- Department of Materials Science and Engineering, University of California, Berkeley, CA, 94720, USA
| | - Subodh Mhaisalkar
- Energy Research Institute @NTU (ERI@N), Research Techno Plaza, X-Frontier Block, Level 5, 50 Nanyang Drive, Singapore, 637553, Singapore
- School of Materials Science and Engineering, Nanyang Technological University, Nanyang Avenue, Singapore, 639798, Singapore
| | - Nripan Mathews
- Energy Research Institute @NTU (ERI@N), Research Techno Plaza, X-Frontier Block, Level 5, 50 Nanyang Drive, Singapore, 637553, Singapore.
- School of Materials Science and Engineering, Nanyang Technological University, Nanyang Avenue, Singapore, 639798, Singapore.
| | - Tze Chien Sum
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore 637371, Singapore.
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17
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Polubothu S, Al-Olabi L, Wilson L, Chong WK, Kinsler VA. Extending the spectrum of AKT1 mosaicism: not just the Proteus syndrome. Br J Dermatol 2016; 175:612-4. [PMID: 26872686 PMCID: PMC5244677 DOI: 10.1111/bjd.14478] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/02/2016] [Indexed: 11/29/2022]
Affiliation(s)
- S Polubothu
- Guy's and St Thomas' NHS Foundation Trust, London, U.K.
| | - L Al-Olabi
- Genetics and Genomic Medicine, UCL Institute of Child Health, London, U.K
| | - L Wilson
- Clinical Genetics, Great Ormond St Hospital for Children, London, U.K
| | - W K Chong
- Department of Radiology, Great Ormond St Hospital for Children, London, U.K
| | - V A Kinsler
- Genetics and Genomic Medicine, UCL Institute of Child Health, London, U.K.,Paediatric Dermatology, Great Ormond St Hospital for Children, London, U.K
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18
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Giovanni D, Chong WK, Dewi HA, Thirumal K, Neogi I, Ramesh R, Mhaisalkar S, Mathews N, Sum TC. Tunable room-temperature spin-selective optical Stark effect in solution-processed layered halide perovskites. Sci Adv 2016; 2:e1600477. [PMID: 27386583 PMCID: PMC4928968 DOI: 10.1126/sciadv.1600477] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2016] [Accepted: 05/26/2016] [Indexed: 05/21/2023]
Abstract
Ultrafast spin manipulation for opto-spin logic applications requires material systems that have strong spin-selective light-matter interaction. Conventional inorganic semiconductor nanostructures [for example, epitaxial II to VI quantum dots and III to V multiple quantum wells (MQWs)] are considered forerunners but encounter challenges such as lattice matching and cryogenic cooling requirements. Two-dimensional halide perovskite semiconductors, combining intrinsic tunable MQW structures and large oscillator strengths with facile solution processability, can offer breakthroughs in this area. We demonstrate novel room-temperature, strong ultrafast spin-selective optical Stark effect in solution-processed (C6H4FC2H4NH3)2PbI4 perovskite thin films. Exciton spin states are selectively tuned by ~6.3 meV using circularly polarized optical pulses without any external photonic cavity (that is, corresponding to a Rabi energy of ~55 meV and equivalent to applying a 70 T magnetic field), which is much larger than any conventional system. The facile halide and organic replacement in these perovskites affords control of the dielectric confinement and thus presents a straightforward strategy for tuning light-matter coupling strength.
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Affiliation(s)
- David Giovanni
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University (NTU), 21 Nanyang Link, Singapore 637371, Singapore
- Energy Research Institute @NTU (ERI@N), Interdisciplinary Graduate School, Nanyang Technological University, 50 Nanyang Avenue, S2-B3a-01, Singapore 639798, Singapore
| | - Wee Kiang Chong
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University (NTU), 21 Nanyang Link, Singapore 637371, Singapore
- Energy Research Institute @NTU (ERI@N), Interdisciplinary Graduate School, Nanyang Technological University, 50 Nanyang Avenue, S2-B3a-01, Singapore 639798, Singapore
| | - Herlina Arianita Dewi
- ERI@N, Research Techno Plaza, X-Frontier Block, Level 5, 50 Nanyang Drive, Singapore 637553, Singapore
| | - Krishnamoorthy Thirumal
- ERI@N, Research Techno Plaza, X-Frontier Block, Level 5, 50 Nanyang Drive, Singapore 637553, Singapore
| | - Ishita Neogi
- ERI@N, Research Techno Plaza, X-Frontier Block, Level 5, 50 Nanyang Drive, Singapore 637553, Singapore
| | - Ramamoorthy Ramesh
- Department of Materials Science and Engineering and Department of Physics, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Subodh Mhaisalkar
- ERI@N, Research Techno Plaza, X-Frontier Block, Level 5, 50 Nanyang Drive, Singapore 637553, Singapore
- School of Materials Science and Engineering, Nanyang Technological University, Nanyang Avenue, Singapore 639798, Singapore
| | - Nripan Mathews
- ERI@N, Research Techno Plaza, X-Frontier Block, Level 5, 50 Nanyang Drive, Singapore 637553, Singapore
- School of Materials Science and Engineering, Nanyang Technological University, Nanyang Avenue, Singapore 639798, Singapore
- Corresponding author. (T.C.S.); (N.M.)
| | - Tze Chien Sum
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University (NTU), 21 Nanyang Link, Singapore 637371, Singapore
- Corresponding author. (T.C.S.); (N.M.)
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19
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Tuschl K, Meyer E, Valdivia LE, Zhao N, Dadswell C, Abdul-Sada A, Hung CY, Simpson MA, Chong WK, Jacques TS, Woltjer RL, Eaton S, Gregory A, Sanford L, Kara E, Houlden H, Cuno SM, Prokisch H, Valletta L, Tiranti V, Younis R, Maher ER, Spencer J, Straatman-Iwanowska A, Gissen P, Selim LAM, Pintos-Morell G, Coroleu-Lletget W, Mohammad SS, Yoganathan S, Dale RC, Thomas M, Rihel J, Bodamer OA, Enns CA, Hayflick SJ, Clayton PT, Mills PB, Kurian MA, Wilson SW. Mutations in SLC39A14 disrupt manganese homeostasis and cause childhood-onset parkinsonism-dystonia. Nat Commun 2016; 7:11601. [PMID: 27231142 PMCID: PMC4894980 DOI: 10.1038/ncomms11601] [Citation(s) in RCA: 188] [Impact Index Per Article: 23.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2015] [Accepted: 04/12/2016] [Indexed: 02/07/2023] Open
Abstract
Although manganese is an essential trace metal, little is known about its transport and homeostatic regulation. Here we have identified a cohort of patients with a novel autosomal recessive manganese transporter defect caused by mutations in SLC39A14. Excessive accumulation of manganese in these patients results in rapidly progressive childhood-onset parkinsonism-dystonia with distinctive brain magnetic resonance imaging appearances and neurodegenerative features on post-mortem examination. We show that mutations in SLC39A14 impair manganese transport in vitro and lead to manganese dyshomeostasis and altered locomotor activity in zebrafish with CRISPR-induced slc39a14 null mutations. Chelation with disodium calcium edetate lowers blood manganese levels in patients and can lead to striking clinical improvement. Our results demonstrate that SLC39A14 functions as a pivotal manganese transporter in vertebrates.
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Affiliation(s)
- Karin Tuschl
- Genetics and Genomic Medicine, UCL Institute of Child Health, University College London, London WC1N 1EH, UK.,Department of Cell and Developmental Biology, University College London, London WC1E 6BT, UK
| | - Esther Meyer
- Developmental Neurosciences, UCL Institute of Child Health, University College London, London WC1N 1EH, UK
| | - Leonardo E Valdivia
- Department of Cell and Developmental Biology, University College London, London WC1E 6BT, UK
| | - Ningning Zhao
- Department of Cell, Development and Cancer Biology, Oregon Health &Sciences University, Portland, Oregon 97239, USA
| | - Chris Dadswell
- Department of Chemistry, School of Life Sciences, University of Sussex, Brighton BN1 9QJ, UK
| | - Alaa Abdul-Sada
- Department of Chemistry, School of Life Sciences, University of Sussex, Brighton BN1 9QJ, UK
| | - Christina Y Hung
- Division of Genetics and Genomics, Department of Medicine, Boston Children's Hospital and Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Michael A Simpson
- Division of Genetics and Molecular Medicine, King's College London School of Medicine, London SE1 9RT, UK
| | - W K Chong
- Department of Radiology, Great Ormond Street Hospital for Children NHS Trust, London WC1N 3JH, UK
| | - Thomas S Jacques
- Developmental Biology and Cancer, UCL Institute of Child Health and Department of Histopathology, Great Ormond Street Hospital for Children NHS Trust, London WC1N 3JH, UK
| | - Randy L Woltjer
- Department of Pathology, Oregon Health &Science University, Portland, Oregon 97239, USA
| | - Simon Eaton
- Developmental Biology and Cancer Programme, UCL Institute of Child Health, University College London, London WC1N 1EH, UK
| | - Allison Gregory
- Department of Molecular &Medical Genetics, Oregon Health &Science University, Portland, Oregon 97239, USA
| | - Lynn Sanford
- Department of Molecular &Medical Genetics, Oregon Health &Science University, Portland, Oregon 97239, USA
| | - Eleanna Kara
- Institute of Neurology, University College London, London WC1N 3BG, UK.,Alzheimer's Disease Research Centre, Department of Neurology, Harvard Medical School and Massachusetts General Hospital, Charlestown, Massachusetts 02129, USA
| | - Henry Houlden
- Institute of Neurology, University College London, London WC1N 3BG, UK
| | - Stephan M Cuno
- Institute of Human Genetics, Technische Universität München, Munich 81675, Germany.,Institute of Human Genetics, Helmholtz Zentrum München, German Research Center for Environmental Health, Neuherberg 85764, Germany
| | - Holger Prokisch
- Institute of Human Genetics, Technische Universität München, Munich 81675, Germany.,Institute of Human Genetics, Helmholtz Zentrum München, German Research Center for Environmental Health, Neuherberg 85764, Germany
| | - Lorella Valletta
- Unit of Molecular Neurogenetics, IRCCS, Foundation Neurological Institute 'C. Besta', Milan 20133, Italy
| | - Valeria Tiranti
- Unit of Molecular Neurogenetics, IRCCS, Foundation Neurological Institute 'C. Besta', Milan 20133, Italy
| | - Rasha Younis
- Department of Medical and Molecular Genetics, University of Birmingham, Birmingham B15 2TT, UK
| | - Eamonn R Maher
- Centre for Rare Diseases and Personalised Medicine, School of Clinical and Experimental Medicine, College of Medical and Dental Sciences, University of Birmingham, Birmingham B15 2TT, UK.,Department of Medical Genetics, School of Clinical Medicine, University of Cambridge, and Cambridge NIHR Biomedical Research Centre, Cambridge CB2 0QQ, UK
| | - John Spencer
- Department of Chemistry, School of Life Sciences, University of Sussex, Brighton BN1 9QJ, UK
| | - Ania Straatman-Iwanowska
- MRC Laboratory for Molecular Cell Biology and Cell Biology Unit, University College London, London WC1E 6BT, UK
| | - Paul Gissen
- Genetics and Genomic Medicine, UCL Institute of Child Health, University College London, London WC1N 1EH, UK.,MRC Laboratory for Molecular Cell Biology and Cell Biology Unit, University College London, London WC1E 6BT, UK.,Department of Metabolic Medicine, Great Ormond Street Hospital for Children NHS Trust, London WC1N 3JH, UK
| | - Laila A M Selim
- Department of Paediatric Neurology, Faculty of Medicine, Cairo University Children's Hospital, Cairo 11432, Egypt
| | - Guillem Pintos-Morell
- Department of Paediatrics, Section of Paediatric Nephrology, Genetics and Metabolism, Unit of Rare Diseases, University Hospital 'Germans Trias I Pujol', Universitat Autònoma de Barcelona, Badalona 08916, Spain
| | - Wifredo Coroleu-Lletget
- Department of Paediatrics, Paediatric Neurology and Neonatology Unit, University Hospital 'Germans Trias I Pujol', Badalona 08916, Spain
| | - Shekeeb S Mohammad
- Neuroimmunology Group, Institute for Neuroscience and Muscle Research, Kids Research Institute at the Children's Hospital at Westmead, University of Sydney, Westmead NSW 2145, Australia
| | - Sangeetha Yoganathan
- Department of Neurological Sciences, Christian Medical College Hospital, Vellore 632 004, India
| | - Russell C Dale
- Neuroimmunology Group, Institute for Neuroscience and Muscle Research, Kids Research Institute at the Children's Hospital at Westmead, University of Sydney, Westmead NSW 2145, Australia
| | - Maya Thomas
- Department of Neurological Sciences, Christian Medical College Hospital, Vellore 632 004, India
| | - Jason Rihel
- Department of Cell and Developmental Biology, University College London, London WC1E 6BT, UK
| | - Olaf A Bodamer
- Division of Genetics and Genomics, Department of Medicine, Boston Children's Hospital and Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Caroline A Enns
- Department of Cell, Development and Cancer Biology, Oregon Health &Sciences University, Portland, Oregon 97239, USA
| | - Susan J Hayflick
- Department of Molecular &Medical Genetics, Oregon Health &Science University, Portland, Oregon 97239, USA.,Department of Neurology, Oregon Health &Science University, Portland, Oregon 97239, USA.,Department of Pediatrics, Oregon Health &Science University, Portland, Oregon 97239, USA
| | - Peter T Clayton
- Genetics and Genomic Medicine, UCL Institute of Child Health, University College London, London WC1N 1EH, UK
| | - Philippa B Mills
- Genetics and Genomic Medicine, UCL Institute of Child Health, University College London, London WC1N 1EH, UK
| | - Manju A Kurian
- Developmental Neurosciences, UCL Institute of Child Health, University College London, London WC1N 1EH, UK
| | - Stephen W Wilson
- Department of Cell and Developmental Biology, University College London, London WC1E 6BT, UK
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20
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Chen S, Roh K, Lee J, Chong WK, Lu Y, Mathews N, Sum TC, Nurmikko A. A Photonic Crystal Laser from Solution Based Organo-Lead Iodide Perovskite Thin Films. ACS Nano 2016; 10:3959-3967. [PMID: 26997122 DOI: 10.1021/acsnano.5b08153] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Perovskite semiconductors are actively investigated for high performance solar cells. Their large optical absorption coefficient and facile solution-based, low-temperature synthesis of thin films make perovskites also a candidate for light-emitting devices across the visible and near-infrared. Specific to their potential as optical gain medium for lasers, early work has demonstrated amplified spontaneous emission and lasing at attractively low thresholds of photoexcitation. Here, we take an important step toward practically usable perovskite lasers where a solution-processed thin film is embedded within a two-dimensional photonic crystal resonator. We demonstrate high degree of temporally and spatially coherent lasing whereby well-defined directional emission is achieved near 788 nm wavelength at optical pumping energy density threshold of 68.5 ± 3.0 μJ/cm(2). The measured power conversion efficiency and differential quantum efficiency of the perovskite photonic crystal laser are 13.8 ± 0.8% and 35.8 ± 5.4%, respectively. Importantly, our approach enables scalability of the thin film lasers to a two-dimensional multielement pixelated array of microlasers which we demonstrate as a proof-of-concept for possible projection display applications.
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Affiliation(s)
- Songtao Chen
- School of Engineering, Brown University , Providence, Rhode Island 02912, United States
| | - Kwangdong Roh
- Department of Physics, Brown University , Providence, Rhode Island 02912, United States
| | - Joonhee Lee
- School of Engineering, Brown University , Providence, Rhode Island 02912, United States
| | - Wee Kiang Chong
- School of Physics & Mathematical Sciences, Nanyang Technological University , Singapore 637371, Singapore
- Energy Research Institute @ NTU (ERI@N), Interdisciplinary Graduate School, Nanyang Technological University , Singapore 637553, Singapore
| | - Yao Lu
- Department of Chemistry, Brown University , Providence, Rhode Island 02912, United States
| | - Nripan Mathews
- School of Materials Science and Engineering, Nanyang Technological University , Singapore 639798, Singapore
- Energy Research Institute @ NTU (ERI@N), Nanyang Technological University , Singapore 637553, Singapore
| | - Tze Chien Sum
- School of Physics & Mathematical Sciences, Nanyang Technological University , Singapore 637371, Singapore
| | - Arto Nurmikko
- School of Engineering, Brown University , Providence, Rhode Island 02912, United States
- Department of Physics, Brown University , Providence, Rhode Island 02912, United States
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21
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Hall-Craggs MA, Williams IG, Wilkinson ID, Paley M, Chinn RJ, Chong WK, Kendall BE, Harrison MJ, Baldeweg T, Pugh K, Riccio M, Catalan J, Weller IV. Proton Spectroscopy in a Cross-Section of HIV-Positive Asymptomatic Patients Receiving Immediate Compared with Deferred Zidovudine (Concorde Study). ACTA ACUST UNITED AC 2016; 1:103-13. [PMID: 16873173 DOI: 10.1300/j128v01n03_06] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The purpose of this study was to examine by proton spectroscopy for any difference in cerebral metabolites in patients taking part in the Concorde study (comparing the efficacy of immediate versus deferred treatment with zidovudine on asymptomatic HIV infected individuals). Forty seven HIV positive male patients [29 immediate, 18 deferred zidovudine] were examined in the last 9 months of the therapeutic trial. Magnetic resonance imaging and proton spectroscopy were performed at 1.5 Tesla using a single voxel placed in the parieto-occipital white matter. No significant difference was found in metabolite ratios comparing immediate versus deferred zidovudine (NA/NA+Cho+Cr 0.52 vs. 0.52). High quality spectra were acquired in relatively large numbers of patients and logistically spectroscopy may be applied to clinical therapeutic studies.
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22
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Sum TC, Mathews N, Xing G, Lim SS, Chong WK, Giovanni D, Dewi HA. Spectral Features and Charge Dynamics of Lead Halide Perovskites: Origins and Interpretations. Acc Chem Res 2016; 49:294-302. [PMID: 26820796 DOI: 10.1021/acs.accounts.5b00433] [Citation(s) in RCA: 70] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Lead halide perovskite solar cells are presently the forerunner among the third generation solution-processed photovoltaic technologies. With efficiencies exceeding 20% and low production costs, they are prime candidates for commercialization. Critical insights into their light harvesting, charge transport, and loss mechanisms have been gained through time-resolved optical probes such as femtosecond transient absorption spectroscopy (fs-TAS), transient photoluminescence spectroscopy, and time-resolved terahertz spectroscopy. Specifically, the discoveries of long balanced electron-hole diffusion lengths and gain properties in halide perovskites underpin their significant roles in uncovering structure-function relations and providing essential feedback for materials development and device optimization. In particular, fs-TAS is becoming increasingly popular in perovskite characterization studies, with commercial one-box pump-probe systems readily available as part of a researcher's toolkit. Although TAS is a powerful probe in the study of charge dynamics and recombination mechanisms, its instrumentation and data interpretation can be daunting even for experienced researchers. This issue is exacerbated by the sensitive nature of halide perovskites where the kinetics are especially susceptible to pump fluence, sample preparation and handling and even degradation effects that could lead to disparate conclusions. Nonetheless, with end-users having a clear understanding of TAS's capabilities, subtleties, and limitations, cutting-edge work with deep insights can still be performed using commercial setups as has been the trend for ubiquitous spectroscopy instruments like absorption, fluorescence, and transient photoluminescence spectrometers. Herein, we will first briefly examine the photophysical processes in lead halide perovskites, highlighting their novel properties. Next, we proceed to give a succinct overview of the fundamentals of pump-probe spectroscopy in relation to the spectral features of halide perovskites and their origins. In the process, we emphasize some key findings of seminal photophysical studies and draw attention to the interpretations that remain divergent and the open questions. This is followed by a general description into how we prepare and conduct the TAS characterization of CH3NH3PbI3 thin films in our laboratory with specific discussions into the potential pitfalls and the influence of thin film processing on the kinetics. Lastly, we conclude with our views on the challenges and opportunities from the photophysical perspective for the field and our expectations for systems beyond lead halide perovskites.
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Affiliation(s)
- Tze Chien Sum
- School
of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, 637371 Singapore
| | - Nripan Mathews
- School
of Materials Science and Engineering, Nanyang Technological University, Nanyang Avenue, 639798 Singapore
- Energy
Research Institute @NTU (ERI@N), Research Techno Plaza, Nanyang Technological University, X-Frontier Block, Level 5, 50 Nanyang Drive, 637553 Singapore
| | - Guichuan Xing
- School
of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, 637371 Singapore
| | - Swee Sien Lim
- School
of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, 637371 Singapore
- Energy
Research Institute @NTU (ERI@N), Interdisciplinary Graduate School Nanyang Technological University, 639798 Singapore
| | - Wee Kiang Chong
- School
of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, 637371 Singapore
- Energy
Research Institute @NTU (ERI@N), Interdisciplinary Graduate School Nanyang Technological University, 639798 Singapore
| | - David Giovanni
- School
of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, 637371 Singapore
- Energy
Research Institute @NTU (ERI@N), Interdisciplinary Graduate School Nanyang Technological University, 639798 Singapore
| | - Herlina Arianita Dewi
- Energy
Research Institute @NTU (ERI@N), Research Techno Plaza, Nanyang Technological University, X-Frontier Block, Level 5, 50 Nanyang Drive, 637553 Singapore
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23
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Lim SS, Chong WK, Solanki A, Dewi HA, Mhaisalkar S, Mathews N, Sum TC. Modulating carrier dynamics through perovskite film engineering. Phys Chem Chem Phys 2016; 18:27119-27123. [DOI: 10.1039/c6cp02640k] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The one-sentence summary that highlights the novelty of our work is, “morphology-kinetics studies on substrate/film-treated perovskite samples reveal that the highly effective toluene-wash processes surprisingly increase trap density in CH3NH3PbI3 films”.
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Affiliation(s)
- Swee Sien Lim
- Energy Research Institute @NTU (ERI@N)
- Interdisciplinary Graduate School Nanyang Technological University
- Singapore
- School of Physical and Mathematical Sciences
- Nanyang Technological University
| | - Wee Kiang Chong
- Energy Research Institute @NTU (ERI@N)
- Interdisciplinary Graduate School Nanyang Technological University
- Singapore
- School of Physical and Mathematical Sciences
- Nanyang Technological University
| | - Ankur Solanki
- School of Physical and Mathematical Sciences
- Nanyang Technological University
- Singapore
| | - Herlina Arianita Dewi
- Energy Research Institute @NTU (ERI@N)
- Research Techno Plaza
- X-Frontier Block
- Level 5
- Singapore
| | - Subodh Mhaisalkar
- Energy Research Institute @NTU (ERI@N)
- Research Techno Plaza
- X-Frontier Block
- Level 5
- Singapore
| | - Nripan Mathews
- Energy Research Institute @NTU (ERI@N)
- Research Techno Plaza
- X-Frontier Block
- Level 5
- Singapore
| | - Tze Chien Sum
- School of Physical and Mathematical Sciences
- Nanyang Technological University
- Singapore
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24
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Chong WK, Thirumal K, Giovanni D, Goh TW, Liu X, Mathews N, Mhaisalkar S, Sum TC. Dominant factors limiting the optical gain in layered two-dimensional halide perovskite thin films. Phys Chem Chem Phys 2016; 18:14701-8. [DOI: 10.1039/c6cp01955b] [Citation(s) in RCA: 62] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
The dominant competing relaxation channels that limit biexciton build-up for population inversion curtails the optical gain in layered (C6H5C2H4NH3)2PbI4 perovskite thin films.
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Affiliation(s)
- Wee Kiang Chong
- Energy Research Institute@NTU
- ERI@N
- Interdisciplinary Graduate School
- Nanyang Technological University
- Singapore
| | - Krishnamoorthy Thirumal
- Energy Research Institute@NTU (ERI@N)
- Research Techno Plaza
- Singapore 637553
- Division of Chemistry and Biological Chemistry
- School of Physical and Mathematical Sciences
| | - David Giovanni
- Energy Research Institute@NTU
- ERI@N
- Interdisciplinary Graduate School
- Nanyang Technological University
- Singapore
| | - Teck Wee Goh
- Division of Physics and Applied Physics
- School of Physical and Mathematical Sciences
- Nanyang Technological University
- Singapore 637371
| | - Xinfeng Liu
- Division of Physics and Applied Physics
- School of Physical and Mathematical Sciences
- Nanyang Technological University
- Singapore 637371
- CAS Key Laboratory of Standardization and Measurement for Nanotechnology
| | - Nripan Mathews
- Energy Research Institute@NTU (ERI@N)
- Research Techno Plaza
- Singapore 637553
- School of Materials Science and Engineering
- Nanyang Technological University
| | - Subodh Mhaisalkar
- Energy Research Institute@NTU (ERI@N)
- Research Techno Plaza
- Singapore 637553
- School of Materials Science and Engineering
- Nanyang Technological University
| | - Tze Chien Sum
- Division of Physics and Applied Physics
- School of Physical and Mathematical Sciences
- Nanyang Technological University
- Singapore 637371
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25
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Jin H, Choi S, Xing G, Lee JH, Kwon Y, Chong WK, Sum TC, Jang HM, Kim S. SnS4(4-), SbS4(3-), and AsS3(3-) Metal Chalcogenide Surface Ligands: Couplings to Quantum Dots, Electron Transfers, and All-Inorganic Multilayered Quantum Dot Sensitized Solar Cells. J Am Chem Soc 2015; 137:13827-35. [PMID: 26460796 DOI: 10.1021/jacs.5b05787] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Three inorganic capping ligands (ICLs) for quantum dots (QDs), SnS4(4-), SbS4(3-) and AsS3(3-), were synthesized and the energy levels determined. Proximity between the ICL LUMO and QD conduction level governed the electronic couplings such as absorption shift upon ligand exchange, and electron transfer rate to TiO2. QD-sensitized solar cells were fabricated, using the ICL-QDs and also using QD multilayers layer-by-layer assembled by bridging coordinations, and studied as a function of the ICL ligand and the number of QD layers.
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Affiliation(s)
- Ho Jin
- Department of Chemistry, Pohang University of Science and Technology , Pohang 790-784, South Korea
| | - Sukyung Choi
- Department of Chemistry, Pohang University of Science and Technology , Pohang 790-784, South Korea
| | - Guichuan Xing
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University , 21 Nanyang Link, Singapore 637371.,Energy Research Institute @NTU (ERI@N), Research Techno Plaza , X-Frontier Block, Level 5, 50 Nanyang Drive, Singapore 637553.,Singapore-Berkeley Research Initiative for Sustainable Energy , 1 Create Way, Singapore 138602
| | - Jung-Hoon Lee
- Department of Material Science and Engineering and Division of Advanced Materials Science, Pohang University of Science and Technology , Pohang 790-784, South Korea
| | - Yongju Kwon
- Department of Chemistry, Pohang University of Science and Technology , Pohang 790-784, South Korea
| | - Wee Kiang Chong
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University , 21 Nanyang Link, Singapore 637371
| | - Tze Chien Sum
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University , 21 Nanyang Link, Singapore 637371.,Energy Research Institute @NTU (ERI@N), Research Techno Plaza , X-Frontier Block, Level 5, 50 Nanyang Drive, Singapore 637553.,Singapore-Berkeley Research Initiative for Sustainable Energy , 1 Create Way, Singapore 138602
| | - Hyun Myung Jang
- Department of Material Science and Engineering and Division of Advanced Materials Science, Pohang University of Science and Technology , Pohang 790-784, South Korea
| | - Sungjee Kim
- Department of Chemistry, Pohang University of Science and Technology , Pohang 790-784, South Korea
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26
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Waelchli R, Aylett SE, Atherton D, Thompson DJ, Chong WK, Kinsler VA. Classification of neurological abnormalities in children with congenital melanocytic naevus syndrome identifies magnetic resonance imaging as the best predictor of clinical outcome. Br J Dermatol 2015; 173:739-50. [PMID: 25966033 PMCID: PMC4737261 DOI: 10.1111/bjd.13898] [Citation(s) in RCA: 67] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/19/2015] [Indexed: 11/28/2022]
Abstract
Background The spectrum of central nervous system (CNS) abnormalities described in association with congenital melanocytic naevi (CMN) includes congenital, acquired, melanotic and nonmelanotic pathology. Historically, symptomatic CNS abnormalities were considered to carry a poor prognosis, although studies from large centres have suggested a much wider variation in outcome. Objectives To establish whether routine MRI of the CNS is a clinically relevant investigation in children with multiple CMN (more than one at birth), and to subclassify radiological abnormalities. Methods Of 376 patients seen between 1991 and 2013, 289 fulfilled our criterion for a single screening CNS MRI, which since 2008 has been more than one CMN at birth, independent of size and site of the largest naevus. Cutaneous phenotyping and radiological variables were combined in a multiple regression model of long‐term outcome measures (abnormal neurodevelopment, seizures, requirement for neurosurgery). Results Twenty‐one per cent of children with multiple CMN had an abnormal MRI. Abnormal MRI was the most significant predictor of all outcome measures. Abnormalities were subclassified into group 1 ‘intraparenchymal melanosis alone’ (n = 28) and group 2 ‘all other pathology’ (n = 18). Group 1 was not associated with malignancy or death during the study period, even when symptomatic with seizures or developmental delay, whereas group 2 showed a much more complex picture, requiring individual assessment. Conclusions For screening for congenital neurological lesions a single MRI in multiple CMN is a clinically relevant strategy. Any child with a stepwise change in neurological/developmental symptoms or signs should have an MRI with contrast of the brain and spine to look for new CNS melanoma. What's already known about this topic? Multiple congenital melanocytic naevi (CMN; more than one lesion at birth) can be associated with abnormalities of the central nervous system (CNS). The spectrum of these abnormalities includes congenital and acquired pathologies, melanotic and nonmelanotic lesions, rendering the term ‘CMN syndrome’ more appropriate than ‘neurocutaneous melanosis’. Symptomatic CNS abnormalities were previously thought to carry a universally poor prognosis, although cohort data in the last decade have argued against this.
What does this study add? A single CNS magnetic resonance imaging scan in multiple CMN, independent of projected adult size or site of the largest naevus, and ideally in the first 6 months of life, is currently an appropriate screening strategy. An abnormal result is a better statistical predictor of clinical outcome than cutaneous phenotype. Clinical management is altered as a result of the radiological result.
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Affiliation(s)
- R Waelchli
- Paediatric Dermatology, Great Ormond St Hospital for Children, London, U.K
| | - S E Aylett
- Neurosciences, Great Ormond St Hospital for Children, London, U.K.,Neurosciences Unit, UCL Institute of Child Health, London, U.K
| | - D Atherton
- Paediatric Dermatology, Great Ormond St Hospital for Children, London, U.K
| | - D J Thompson
- Paediatric Neurosurgery, Great Ormond St Hospital for Children, London, U.K
| | - W K Chong
- Paediatric Neuroradiology, Great Ormond St Hospital for Children, London, U.K
| | - V A Kinsler
- Paediatric Dermatology, Great Ormond St Hospital for Children, London, U.K.,Genetics and Genomic Medicine, UCL Institute of Child Health, London, U.K
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27
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Arthurs OJ, Thayyil S, Pauliah SS, Jacques TS, Chong WK, Gunny R, Saunders D, Addison S, Lally P, Cady E, Jones R, Norman W, Scott R, Robertson NJ, Wade A, Chitty L, Taylor AM, Sebire NJ. Diagnostic accuracy and limitations of post-mortem MRI for neurological abnormalities in fetuses and children. Clin Radiol 2015; 70:872-80. [PMID: 26050535 DOI: 10.1016/j.crad.2015.04.008] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2015] [Revised: 03/04/2015] [Accepted: 04/13/2015] [Indexed: 10/23/2022]
Abstract
AIM To compare the diagnostic accuracy of non-invasive cerebral post-mortem magnetic resonance imaging (PMMRI) specifically for cerebral and neurological abnormalities in a series of fetuses and children, compared to conventional autopsy. MATERIALS AND METHODS Institutional ethics approval and parental consent was obtained. Pre-autopsy cerebral PMMRI was performed in a sequential prospective cohort (n = 400) of fetuses (n = 277; 185 ≤ 24 weeks and 92 > 24 weeks gestation) and children <16 years (n = 123) of age. PMMRI and conventional autopsy findings were reported blinded and independently of each other. RESULTS Cerebral PMMRI had sensitivities and specificities (95% confidence interval) of 88.4% (75.5 to 94.9), and 95.2% (92.1 to 97.1), respectively, for cerebral malformations; 100% (83.9 to 100), and 99.1% (97.2 to 99.7) for major intracranial bleeds; and 87.5% (80.1 to 92.4) and 74.1% (68 to 79.4) for overall brain pathology. Formal neuropathological examination was non-diagnostic due to maceration/autolysis in 43/277 (16%) fetuses; of these, cerebral PMMRI imaging provided clinically important information in 23 (53%). The sensitivity of PMMRI for detecting significant ante-mortem ischaemic injury was only 68% (48.4 to 82.8) overall. CONCLUSIONS PMMRI is an accurate investigational technique for identifying significant neuropathology in fetuses and children, and may provide important information even in cases where autolysis prevents formal neuropathological examination; however, PMMRI is less sensitive at detecting hypoxic-ischaemic brain injury, and may not detect rarer disorders not encountered in this study.
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Affiliation(s)
- O J Arthurs
- Paediatric Radiology, Great Ormond Street Hospital for Children NHS Foundation Trust, London, WC1N 3JH, UK; UCL Institute of Child Health, London, UK.
| | - S Thayyil
- Perinatal Neurology and Neonatology, Imperial College London, London, UK
| | - S S Pauliah
- Perinatal Neurology and Neonatology, Imperial College London, London, UK
| | - T S Jacques
- Department of Histopathology, UCL Institute of Child Health & Great Ormond Street Hospital for Children, London, UK
| | - W K Chong
- Paediatric Radiology, Great Ormond Street Hospital for Children NHS Foundation Trust, London, WC1N 3JH, UK; UCL Institute of Child Health, London, UK
| | - R Gunny
- Paediatric Radiology, Great Ormond Street Hospital for Children NHS Foundation Trust, London, WC1N 3JH, UK; UCL Institute of Child Health, London, UK
| | - D Saunders
- Paediatric Radiology, Great Ormond Street Hospital for Children NHS Foundation Trust, London, WC1N 3JH, UK; UCL Institute of Child Health, London, UK
| | - S Addison
- Perinatal Neurology and Neonatology, Imperial College London, London, UK
| | - P Lally
- Perinatal Neurology and Neonatology, Imperial College London, London, UK
| | - E Cady
- Medical Physics and Bioengineering, University College London Hospitals NHS Foundation Trust, London, UK
| | - R Jones
- Centre for Cardiovascular Imaging, UCL Institute of Cardiovascular Science, London, UK; Cardiorespiratory Division, Great Ormond Street Hospital for Children NHS Foundation Trust, London, UK
| | - W Norman
- Centre for Cardiovascular Imaging, UCL Institute of Cardiovascular Science, London, UK; Cardiorespiratory Division, Great Ormond Street Hospital for Children NHS Foundation Trust, London, UK
| | - R Scott
- Department of Histopathology, University College London Hospital NHS Trust, UK
| | - N J Robertson
- Academic Neonatology, UCL Institute for Women's Health, London, UK
| | - A Wade
- Paediatric Epidemiology and Biostatistics Unit, UCL Institute of Child Health, London, UK
| | - L Chitty
- Genetics and Genomic Medicine, UCL Institute of Child Health, London, UK; Clinical Genetics, Great Ormond Street Hospital for Children NHS Foundation Trust, London, UK; UCLH NHS Foundation Trusts, London, UK
| | - A M Taylor
- Centre for Cardiovascular Imaging, UCL Institute of Cardiovascular Science, London, UK; Cardiorespiratory Division, Great Ormond Street Hospital for Children NHS Foundation Trust, London, UK
| | - N J Sebire
- UCL Institute of Child Health, London, UK; Department of Histopathology, UCL Institute of Child Health & Great Ormond Street Hospital for Children, London, UK
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28
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Liu X, Zhang Q, Chong WK, Yip JN, Wen X, Li Z, Wei F, Yu G, Xiong Q, Sum TC. Cooperative Enhancement of Second-Harmonic Generation from a Single CdS Nanobelt-Hybrid Plasmonic Structure. ACS Nano 2015; 9:5018-5026. [PMID: 25905978 DOI: 10.1021/nn5072045] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Semiconductor nanostructures (e.g., nanowires and nanobelts) hold great promise as subwavelength coherent light sources, nonlinear optical frequency converters, and all-optical signal processors for optoelectronic applications. However, at such small scales, optical second-harmonic generation (SHG) is generally inefficient. Herein, we report on a straightforward strategy using a thin Au layer to enhance the SHG from a single CdS nanobelt by 3 orders of magnitude. Through detailed experimental and theoretical analysis, we validate that the augmented SHG originates from the mutual intensification of the local fields induced by the plasmonic nanocavity and by the reflections within the CdS Fabry-Pérot resonant cavity in this hybrid semiconductor-metal system. Polarization-dependent SHG measurements can be employed to determine and distinguish the contributions of SH signals from the CdS nanobelt and gold film, respectively. When the thickness of gold film becomes comparable to the skin depth, SHG from the gold film can be clearly observed. Our work demonstrates a facile approach for tuning the nonlinear optical properties of mesoscopic, nanostructured, and layered semiconductor materials.
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Affiliation(s)
- Xinfeng Liu
- †Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371
| | - Qing Zhang
- †Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371
| | - Wee Kiang Chong
- †Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371
| | - Jing Ngei Yip
- †Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371
| | - Xinglin Wen
- †Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371
| | - Zhenpeng Li
- †Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371
| | - Fengxia Wei
- ‡Energy Research Institute@NTU (ERI@N), Nanyang Technological University, 50 Nanyang Drive, Singapore 637553
| | - Guannan Yu
- †Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371
| | - Qihua Xiong
- †Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371
- §NOVITAS, Nanoelectronics Center of Excellence, School of Electrical and Electronic Engineering, Nanyang Technological University, Singapore 639798
| | - Tze Chien Sum
- †Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371
- ‡Energy Research Institute@NTU (ERI@N), Nanyang Technological University, 50 Nanyang Drive, Singapore 637553
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Abstract
Deliberate inflicted trauma to children has irrefutably occurred for centuries but the notion of non-accidental injury (NAI) as a distinct clinical entity has only relatively recently been described. Awareness and understanding of this syndrome of abuse has increased greatly in recent decades, although many alternative names have been given to the condition and uncertainty remains as to what exactly comprises the syndrome. What is not in question, however, is the role of imaging; the radiologist is often at the front line in terms of raising the spectre of NAI and in assessing the probability given the objective imaging features available. Non-accidental head injury (NAHI) encompasses a broad spectrum of manifestations, ranging from trivial superficial injuries to potentially fatal severe brain trauma. In this review, we aim to introduce the epidemiological, historical and legal aspects of NAI. Focussing specifically on NAHI, current biomechanical theories and neuropathological aspects will be discussed. Finally, the patterns of injury and prognosticating features with respect to the various imaging modalities will be covered, with careful consideration given to differential diagnoses and syndrome mimics.
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Affiliation(s)
- Amit A Roy
- St Bartholomew's and the Royal London Hospitals, UK.
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Waelchli R, Aylett SE, Robinson K, Chong WK, Martinez AE, Kinsler VA. New vascular classification of port-wine stains: improving prediction of Sturge-Weber risk. Br J Dermatol 2014; 171:861-7. [PMID: 24976116 PMCID: PMC4284033 DOI: 10.1111/bjd.13203] [Citation(s) in RCA: 119] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/16/2014] [Indexed: 01/19/2023]
Abstract
BACKGROUND Facial port-wine stains (PWSs) are usually isolated findings; however, when associated with cerebral and ocular vascular malformations they form part of the classical triad of Sturge-Weber syndrome (SWS). OBJECTIVES To evaluate the associations between the phenotype of facial PWS and the diagnosis of SWS in a cohort with a high rate of SWS. METHODS Records were reviewed of all 192 children with a facial PWS seen in 2011-13. Adverse outcome measures were clinical (seizures, abnormal neurodevelopment, glaucoma) and radiological [abnormal magnetic resonance imaging (MRI)], modelled by multivariate logistic regression. RESULTS The best predictor of adverse outcomes was a PWS involving any part of the forehead, delineated at its inferior border by a line joining the outer canthus of the eye to the top of the ear, and including the upper eyelid. This involves all three divisions of the trigeminal nerve, but corresponds well to the embryonic vascular development of the face. Bilateral distribution was not an independently significant phenotypic feature. Abnormal MRI was a better predictor of all clinical adverse outcome measures than PWS distribution; however, for practical reasons guidelines based on clinical phenotype are proposed. CONCLUSIONS Facial PWS distribution appears to follow the embryonic vasculature of the face, rather than the trigeminal nerve. We propose that children with a PWS on any part of the 'forehead' should have an urgent ophthalmology review and a brain MRI. A prospective study has been established to test the validity of these guidelines.
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Affiliation(s)
- R Waelchli
- Department of Paediatric Dermatology, Great Ormond Street Hospital for Children, London, WC1N 3JH, U.K
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31
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Thust SC, Blanco E, Michalski AJ, Chong WK, Gaze MN, Phipps K, Mankad K. MRI abnormalities in children following sequential chemotherapy, hyperfractionated accelerated radiotherapy and high-dose thiotepa for high-risk primitive neuroectodermal tumours of the central nervous system. J Med Imaging Radiat Oncol 2014; 58:683-90. [DOI: 10.1111/1754-9485.12232] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2014] [Accepted: 07/26/2014] [Indexed: 11/28/2022]
Affiliation(s)
- Stefanie C Thust
- Department of Paediatric Neuroradiology; Great Ormond Street Hospital for Children NHS Foundation Trust; London UK
- Department of Oncology; University College London Hospitals NHS Foundation Trust; London UK
| | - Esther Blanco
- Department of Paediatric Oncology; Great Ormond Street Hospital for Children NHS Foundation Trust; London UK
| | - Antony J Michalski
- Department of Paediatric Oncology; Great Ormond Street Hospital for Children NHS Foundation Trust; London UK
| | - WK Chong
- Department of Paediatric Neuroradiology; Great Ormond Street Hospital for Children NHS Foundation Trust; London UK
| | - Mark N Gaze
- Department of Oncology; University College London Hospitals NHS Foundation Trust; London UK
- Department of Paediatric Oncology; Great Ormond Street Hospital for Children NHS Foundation Trust; London UK
| | - Kim Phipps
- Department of Paediatric Oncology; Great Ormond Street Hospital for Children NHS Foundation Trust; London UK
| | - Kshitij Mankad
- Department of Paediatric Neuroradiology; Great Ormond Street Hospital for Children NHS Foundation Trust; London UK
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Papandreou A, Tisdall MM, Chong WK, Cross JH, Harkness WF, Varadkar SM. COL4A1 mutations should not be a contraindication for epilepsy surgery. Childs Nerv Syst 2014; 30:1467-9. [PMID: 24864020 DOI: 10.1007/s00381-014-2440-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/10/2014] [Accepted: 05/10/2014] [Indexed: 11/26/2022]
Abstract
PURPOSE We describe the first case in the literature of complication-free epilepsy surgery in a paediatric patient with collagen type IV alpha 1 (COL4A1) mutation. METHODS This is a case report. RESULTS COL4A1 mutations disrupt the integrity of vascular basement membranes, so predisposing to a broad spectrum of disorders including periventricular leucomalacia, haemorrhagic stroke, aneurysm formation, epilepsy and developmental delay. Intracranial haemorrhage is reported and may be recurrent or associated with trauma and anticoagulant therapy. Children have an increased risk of stroke with general anaesthesia. A 6-year-old girl, COL4A1 mutation positive, had drug-resistant epilepsy, cerebral palsy and developmental delay. Following presurgical evaluation, she was a candidate for corpus callosotomy. Previous general anaesthesia had been uncomplicated. Preoperative full blood count and coagulation studies were normal. Perioperatively, normotension was maintained, and anticoagulation was avoided. A complete corpus callosotomy was performed with no intracranial haemorrhage or other perioperative complications. CONCLUSION Although there is an increased risk of intracranial haemorrhages in COL4A1 patients, this is not clearly quantifiable. There are minimal data in the literature on the subject. COL4A1 mutations should not be a contraindication for presurgical evaluation. Each patient should be individually evaluated and assessed, risks and benefits were carefully weighed, and informed decisions were reached after thorough discussions with patients and families.
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Affiliation(s)
- Apostolos Papandreou
- Paediatric Neurology Department, Great Ormond Street Hospital, Great Ormond Street, London, WC1N 3JH, UK,
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Illingworth MA, Meyer E, Chong WK, Manzur AY, Carr LJ, Younis R, Hardy C, McDonald F, Childs AM, Stewart B, Warren D, Kneen R, King MD, Hayflick SJ, Kurian MA. PLA2G6-associated neurodegeneration (PLAN): further expansion of the clinical, radiological and mutation spectrum associated with infantile and atypical childhood-onset disease. Mol Genet Metab 2014; 112:183-9. [PMID: 24745848 PMCID: PMC4048546 DOI: 10.1016/j.ymgme.2014.03.008] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/21/2014] [Accepted: 03/21/2014] [Indexed: 11/18/2022]
Abstract
Phospholipase A2 associated neurodegeneration (PLAN) is a major phenotype of autosomal recessive Neurodegeneration with Brain Iron Accumulation (NBIA). We describe the clinical phenotypes, neuroimaging features and PLA2G6 mutations in 5 children, of whom 4 presented with infantile neuroaxonal dystrophy (INAD). One other patient was diagnosed with the onset of PLAN in childhood, and our report highlights the diagnostic challenges associated with this atypical PLAN subtype. In this series, the neuroradiological relevance of classical PLAN features as well as apparent claval hypertrophy' is explored. Novel PLA2G6 mutations were identified in all patients. PLAN should be considered not only in patients presenting with a classic INAD phenotype but also in older patients presenting later in childhood with non-specific progressive neurological features including social communication difficulties, gait disturbance, dyspraxia, neuropsychiatric symptoms and extrapyramidal motor features.
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Affiliation(s)
- M A Illingworth
- Department of Neurology, Great Ormond Street Hospital, London, UK
| | - E Meyer
- Neurosciences Unit, UCL-Institute of Child Health, London, UK
| | - W K Chong
- Department of Radiology, Great Ormond Street Hospital, London, UK
| | - A Y Manzur
- Dubowitz Neuromuscular Centre for Congenital Muscular Dystrophies and Myopathies, Great Ormond Street Hospital, London, UK
| | - L J Carr
- Department of Neurology, Great Ormond Street Hospital, London, UK
| | - R Younis
- West Midlands Regional Genetics, Birmingham Women's Hospital, Birmingham, UK
| | - C Hardy
- West Midlands Regional Genetics, Birmingham Women's Hospital, Birmingham, UK
| | - F McDonald
- West Midlands Regional Genetics, Birmingham Women's Hospital, Birmingham, UK
| | - A M Childs
- Department of Paediatric Neurology, Leeds General Infirmary, Leeds, UK
| | - B Stewart
- Department of Paediatrics, York Teaching Hospitals NHS Foundation Trust, York, UK
| | - D Warren
- Department of Neuroradiology, Leeds teaching Hospitals, Leeds. UK
| | - R Kneen
- Department of Neurology, Alder Hey Children's Hospital, Liverpool, UK
| | - M D King
- Department of Paediatric Neurology, Children's University Hospital, Temple Street, Dublin, Ireland
| | - S J Hayflick
- Department of Molecular & Medical Genetics, OR Health & Science University, Portland 97239, USA; Department of Paediatrics, OR Health & Science University, Portland 97239, USA; Department of Neurology, OR Health & Science University, Portland 97239, USA
| | - M A Kurian
- Department of Neurology, Great Ormond Street Hospital, London, UK; Neurosciences Unit, UCL-Institute of Child Health, London, UK.
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Griffiths ST, Elgen IB, Chong WK, Odberg MD, Markestad T, Neto E, Aukland SM. Cerebral magnetic resonance imaging findings in children born extremely preterm, very preterm, and at term. Pediatr Neurol 2013; 49:113-8. [PMID: 23859857 DOI: 10.1016/j.pediatrneurol.2013.03.006] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/17/2012] [Revised: 02/25/2013] [Accepted: 03/10/2013] [Indexed: 11/18/2022]
Abstract
BACKGROUND The aim of this study was to compare findings on cerebral MRI scans of infants born extremely preterm (i.e., gestation < 28 weeks, very preterm; gestation 28-31 weeks) and at term. METHODS MRI scans obtained in a cohort of 29 extremely preterm children at 11 years, 51 very preterm young adults at 19 years, and respective term-born controls were scored according to presence and degree of MRI pathology. RESULTS MRI pathology was found in 76% of the extremely preterm children vs 31% of their controls (odds ratio 4.3; 95% confidence interval, 1.5-137.5) and in 55% of the very preterm group vs 19% of their controls (odds ratio 5.2; 95% confidence interval, 2.5-10.9). The distribution of moderate and severe pathology did not differ among the groups. CONCLUSIONS The extremely preterm, very preterm, and term subjects shared the same morphological pathology, revealing no specific preterm MRI pattern, but both premature cohorts had higher frequencies. Differences were mainly limited to mild pathology. Whether MRI lesions were more common in the extremely preterm than in the very preterm group is uncertain as the difference in frequency was similar in the two control groups, suggesting a lack of objective criteria for differentiating mild pathology from normality or that MRI scans normally differ at 11 and 19 years of age.
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Arthurs OJ, Thayyil S, Wade A, Chong WK, Sebire NJ, Taylor AM. Normal ascent of the conus medullaris: a post-mortem foetal MRI study. J Matern Fetal Neonatal Med 2012; 26:697-702. [PMID: 23211127 DOI: 10.3109/14767058.2012.746307] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
OBJECTIVES The position of the conus medullaris is considered abnormal if it ends below lumbar vertebrae three (L3) at birth. We used magnetic resonance imaging (MRI) to measure the position of the conus in post-mortem foetuses, to investigate the timing of normal ascent. METHODS The position of the conus in 84 post-mortem foetuses (mean gestation 26.3 weeks; range 14-41 weeks) was identified using 3D MRI datasets. A numerical scale was used for vertebral levels, from 1 (S2) to 15 (T12). RESULTS There was significant ascent of the conus medullaris with increasing gestation. At 20 weeks gestation, an estimated 84.2% (95% confidence interval (CI): 72.9, 93.2%) of foetuses have a conus position of L4/5 or higher, but only 22.8% (95% CI 11.7, 34.9%) at L3 or higher. By 26 weeks, an estimated 50.7% (95% CI 34.1, 67.5) will have reached L3, and 94.8% (95% CI 87.0, 98.5%) reach L3 by 40 weeks. CONCLUSION There is regular ascent of the conus throughout foetal life. Although growth for each individual foetus may be non-linear, most foetuses have a conus level within the normal adult range by 33 weeks gestation.
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Affiliation(s)
- O J Arthurs
- Great Ormond Street Hospital for Children, London, WC1N 3JH, UK.
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36
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Stamelou M, Tuschl K, Chong WK, Burroughs AK, Mills PB, Bhatia KP, Clayton PT. Dystonia with brain manganese accumulation resulting from SLC30A10 mutations: a new treatable disorder. Mov Disord 2012; 27:1317-22. [PMID: 22926781 PMCID: PMC3664426 DOI: 10.1002/mds.25138] [Citation(s) in RCA: 89] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2012] [Revised: 05/22/2012] [Accepted: 07/03/2012] [Indexed: 11/12/2022] Open
Abstract
Background The first gene causing early-onset generalized dystonia with brain manganese accumulation has recently been identified. Mutations in the SLC30A10 gene, encoding a manganese transporter, cause a syndrome of hepatic cirrhosis, dystonia, polycythemia, and hypermanganesemia. Methods We present 10-year longitudinal clinical features, MRI data, and treatment response to chelation therapy of the originally described patient with a proven homozygous mutation in SLC30A10. Results The patient presented with early-onset generalized dystonia and mild hyperbilirubinemia accompanied by elevated whole-blood manganese levels. T1-sequences in MRI showed hyperintensities in the basal ganglia and cerebellum, characteristic of manganese deposition. Treatment with intravenous disodium calcium edetate led to clinical improvement and reduction of hyperintensities in brain imaging. Conclusions We wish to highlight this rare disorder, which, together with Wilson's disease, is the only potentially treatable inherited metal storage disorder to date, that otherwise can be fatal as a result of complications of cirrhosis. © 2012 Movement Disorder Society
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Affiliation(s)
- Maria Stamelou
- Sobell Department of Motor Neuroscience and Movement Disorders, University College London Institute of Neurology, London, United Kingdom
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Baker K, Northam GB, Chong WK, Banks T, Beales P, Baldeweg T. Neocortical and hippocampal volume loss in a human ciliopathy: A quantitative MRI study in Bardet-Biedl syndrome. Am J Med Genet A 2010; 155A:1-8. [PMID: 21204204 DOI: 10.1002/ajmg.a.33773] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2010] [Accepted: 09/11/2010] [Indexed: 11/08/2022]
Abstract
Cilia are ubiquitous cell surface organelles with diverse roles from embryogenesis to adult life. The neurodevelopmental functions of the cilium are currently under investigation in animal systems, but relevance to human brain development remains uncertain. We present the first systematic investigation of structural neuroanatomy in a ciliopathy-Bardet-Biedl syndrome (BBS). Qualitative and quantitative aspects of brain structure were evaluated via magnetic resonance imaging in 10 patients with BBS (ages 14-28 years). In comparison to age and gender-matched healthy controls, BBS patients had significantly reduced total gray matter (GM) volume but no total white matter (WM) or cerebrospinal fluid volume changes. Voxel-based morphometric analysis indicated regional GM volume loss bilaterally in the anterior temporal lobes and in the medial orbitofrontal cortex, and WM volume loss in the right inferior longitudinal fasciculus. Region-of-interest measurements revealed reduced volume of the hippocampus. Two patients were found to have ventriculomegaly. Global GM reduction and regional volume reductions in the temporal lobe may underlie the learning disabilities and behavioral problems experienced by some patients with BBS. These findings are consistent with previous observations in mouse models of BBS, and further implicate the cilium in neurodevelopmental processes relevant to human cognitive function.
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Affiliation(s)
- Kate Baker
- UCL Institute of Child Health, London, UK.
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Mc Sweeney N, Grunewald S, Bhate S, Ganesan V, Chong WK, Hemingway C. Two unusual clinical and radiological presentations of biotinidase deficiency. Eur J Paediatr Neurol 2010; 14:535-8. [PMID: 20153672 DOI: 10.1016/j.ejpn.2010.01.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/30/2009] [Revised: 12/11/2009] [Accepted: 01/11/2010] [Indexed: 10/19/2022]
Abstract
Biotinidase deficiency is due to a defect in recycling of biotin and is a treatable autosomal recessive inherited disorder. We describe two cases with unusual presenting symptoms and rarely described MRI findings. We propose that the diagnosis of biotinidase deficiency should be considered when there are symmetrical MRI changes in the medial thalamus, dorsal brainstem, medulla and spinal cord as in our two cases. As long as there isn't newborn screening for biotinidase deficiency in the UK; increased awareness of this disorder and recognition of biotinidase deficiency as a cause of bilateral symmetrical MRI patterns similar to our patients, would facilitate early diagnosis and prevent many of the devastating neurological sequelae associated with missing the condition.
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Affiliation(s)
- N Mc Sweeney
- Department of Paediatric Neurology, Great Ormond Street Hospital for Children, NHS Trust, London, UK
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39
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Grundy RG, Wilne SH, Robinson KJ, Ironside JW, Cox T, Chong WK, Michalski A, Campbell RHA, Bailey CC, Thorp N, Pizer B, Punt J, Walker DA, Ellison DW, Machin D. Primary postoperative chemotherapy without radiotherapy for treatment of brain tumours other than ependymoma in children under 3 years: results of the first UKCCSG/SIOP CNS 9204 trial. Eur J Cancer 2010; 46:120-33. [PMID: 19818598 DOI: 10.1016/j.ejca.2009.09.013] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2009] [Revised: 09/07/2009] [Accepted: 09/10/2009] [Indexed: 11/28/2022]
Abstract
BACKGROUND Radiotherapy is an effective adjuvant treatment for brain tumours arising in very young children, but it has the potential to damage the child's developing nervous system at a crucial time - with a resultant reduction in IQ leading to cognitive impairment, associated endocrinopathy and risk of second malignancy. We aimed to assess the role of a primary chemotherapy strategy in avoiding or delaying radiotherapy in children younger than 3 years with malignant brain tumours other than ependymoma, the results of which have already been published. METHODS Ninety-seven children were enrolled between March 1993 and July 2003 and, following diagnostic review, comprised: medulloblastoma (n=31), astrocytoma (26), choroid plexus carcinoma [CPC] (15), CNS PNET (11), atypical teratoid/rhabdoid tumours [AT/RT] (6) and ineligible (6). Following maximal surgical resection, chemotherapy was delivered every 14 d for 1 year or until disease progression. Radiotherapy was withheld in the absence of progression. FINDINGS Over all diagnostic groups the cumulative progression rate was 80.9% at 5 years while the corresponding need-for-radiotherapy rate for progression was 54.6%, but both rates varied by tumour type. There was no clear relationship between chemotherapy dose intensity and outcome. Patients with medulloblastoma presented as a high-risk group, 83.9% having residual disease and/or metastases at diagnosis. For these patients, outcome was related to histology. The 5-year OS for desmoplastic/nodular medulloblastoma was 52.9% (95% confidence interval (CI): 27.6-73.0) and for classic medulloblastoma 33.3% (CI: 4.6-67.6); the 5-year EFS were 35.3% (CI: 14.5-57.0) and 33.3% (CI: 4.6-67.6), respectively. All children with large cell or anaplastic variants of medulloblastoma died within 2 years of diagnosis. The 5-year EFS for non-brainstem high-grade gliomas [HGGs] was 13.0% (CI: 2.2-33.4) and the OS was 30.9% (CI: 11.5-52.8). For CPC the 5-year OS was 26.67% (CI: 8.3-49.6) without RT. This treatment strategy was less effective for AT/RT with 3-year OS of 16.7% (CI: 0.8-51.7) and CNS PNET with 1-year OS of 9.1% (CI: 0.5-33.3). INTERPRETATION The outcome for very young children with brain tumours is dictated by degree of surgical resection and histological tumour type and underlying biology as an indicator of treatment sensitivity. Overall, the median age at radiotherapy was 3 years and radiotherapy was avoided in 45% of patients. Desmoplastic/nodular sub-type of medulloblastoma has a better prognosis than classic histology, despite traditional adverse clinical features of metastatic disease and incomplete surgical resection. A subgroup with HGG and CPC are long-term survivors without RT. This study highlights the differing therapeutic challenges presented by the malignant brain tumours of early childhood, the importance of surgical approaches and the need to explore individualised brain sparing approaches to the range of malignant brain tumours that present in early childhood.
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Affiliation(s)
- R G Grundy
- Children's Brain Tumour Research Centre, University of Nottingham, Queen's Medical Centre, Nottingham, UK.
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Mehta A, Hindmarsh PC, Mehta H, Turton JPG, Russell-Eggitt I, Taylor D, Chong WK, Dattani MT. Congenital hypopituitarism: clinical, molecular and neuroradiological correlates. Clin Endocrinol (Oxf) 2009; 71:376-82. [PMID: 19320653 DOI: 10.1111/j.1365-2265.2009.03572.x] [Citation(s) in RCA: 79] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
OBJECTIVE Recent studies have suggested that mutations in genes encoding several hypothalamo-pituitary (H-P) transcription factors result in hypopituitarism [isolated GH deficiency (IGHD) and combined pituitary hormone deficiency (CPHD)], which may in turn be related to the neuroanatomy revealed by magnetic resonance (MR) imaging. Although studies have focused on patients with either optic nerve hypoplasia (ONH) or isolated hypopituitarism with normal optic nerves, few studies have compared the two groups. We aimed to relate the clinical phenotype of a large cohort (n = 170) of children with congenital hypopituitarism including septo-optic dysplasia (SOD) attending a single centre to the neuroradiological and genetic findings. DESIGN Clinical, biochemical, MR imaging and molecular data were analysed retrospectively in 170 patients with or 'at-risk' (with ONH) of hypopituitarism to determine predictors of hypopituitarism. RESULTS The presence of ONH was significantly associated with an absent septum pellucidum [odds ratio (OR) 31.5, 95% confidence intervals (CI) 7.3-136.6, P < 0.001], an abnormal corpus callosum (OR 10.5, 95% CI 3.8-28.6, P < 0.001) and stalk abnormalities (OR 2.3, 95% CI 1.2-4.2, P = 0.009). The risk of hypopituitarism was 27.2 times greater in patients with an undescended posterior pituitary (95% CI 3.6-205.1, P < 0.001). Anterior pituitary hypoplasia (OR 3.1, 95% CI 1.3-7.0, P = 0.006) and an absent pituitary stalk (P < 0.001) were also significantly associated with hypopituitarism. With respect to the type or severity of hypopituitarism, CPHD was more often associated with an abnormal corpus callosum (OR 6.1, 95% CI 1.4-27.4, P = 0.008) and stalk abnormalities (OR 2.8, 95% CI 1.3-6.1, P = 0.006). Male to female ratio was significantly greater in patients with normal optic nerves (3.3:1) as compared with those with ONH (1.2:1). The prevalence of diabetes insipidus, thyrotrophin and ACTH deficiencies was significantly greater in patients with ONH as compared with 'idiopathic' hypopituitarism. Mutations in pituitary transcription factors and genes regulating GH secretion were rare (5/170) in this cohort of patients with sporadic hypopituitarism. CONCLUSION Our data suggest that individuals presenting with ONH are at high risk for neuroradiologic and endocrine abnormalities. The neuroradiologic features are predictive not only of the presence, but also of the type, of hypopituitarism. The association of midline abnormalities with hypopituitarism in this cohort suggests a common developmental origin for these features, the aetiology of which remains unidentified in the majority of cases.
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Affiliation(s)
- Ameeta Mehta
- Developmental Endocrinology Research Group, Institute of Child Health and Great Ormond Street Hospital for Sick Children, University College London, London, UK
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Kinsler VA, Chong WK, Aylett SE, Atherton DJ. Complications of congenital melanocytic naevi in children: analysis of 16 years' experience and clinical practice. Br J Dermatol 2008; 159:907-14. [PMID: 18671780 DOI: 10.1111/j.1365-2133.2008.08775.x] [Citation(s) in RCA: 115] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
BACKGROUND Congenital melanocytic naevi (CMNs) can be associated with abnormalities of the cental nervous system (CNS) and/or with melanoma. Quoted incidences for these complications vary in the literature, as do recommendations for investigations and follow-up. OBJECTIVES To determine the incidence of complications, and to identify phenotypic features associated with a higher risk of complications. METHODS We reviewed records of 224 patients with CMNs seen in Dermatology clinic between 1991 and 2007. Patients were excluded if they had a complication at the time of referral. Magnetic resonance imaging (MRI) of the CNS was offered on the basis of CMN phenotype. Follow up was in clinic and/or by postal questionnaires. RESULTS One hundred and twenty patients (54 boys and 66 girls) who had MRI of the CNS were included in the analysis. Mean age at MRI was 2.46 years (median 1.20). Mean follow up was 8.35 years (median 7.86). Sixty-five per cent had naevi > 20 cm projected adult size or multiple CMNs (40% > 40 cm), and 83% had satellite lesions at birth. Outcome measures were MRI abnormality, clinical neurological abnormality, any tumour, malignant melanoma, and death. No complications were seen in the 16 patients with no satellite lesions at birth. MRI and/or clinical neurological abnormalities were found in 22 patients (18%) and were significantly associated with projected adult size of the CMN (particularly > 40 cm), and independently with male gender. Tumours occurred in five patients, two of which were malignant melanoma (1.7%). Due to small numbers there was no significant association between phenotype and occurrence of tumours. Three patients (2.5%) died (one from neuromelanosis and two from melanoma in patients with normal MRI scans). Death was significantly associated with CMN size > 40 cm. Importantly, there was no significant association between CMN distribution (including posterior axial location) and adverse outcomes. CONCLUSIONS This is the largest study of CNS imaging in patients with CMNs. We report a newly recognized association between male gender and neurological complications, dispute the previously reported association between CMN site and neurological complications, and quantify the associations between CMN size, satellite lesions and neurological complications. We make recommendations for the management of these patients.
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Affiliation(s)
- V A Kinsler
- Department of Dermatology, Great Ormond Street Hospital for Children NHS Trust, Great Ormond Street, London, WC1N 3JH, UK.
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Bamiou DE, Campbell NG, Musiek FE, Taylor R, Chong WK, Moore A, van Heyningen V, Free S, Sisodiya S, Luxon LM. Auditory and verbal working memory deficits in a child with congenital aniridia due to a PAX6 mutation. Int J Audiol 2007; 46:196-202. [PMID: 17454233 DOI: 10.1080/14992020601175952] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
PAX6 encodes a transcriptional regulator that is essential for brain morphogenesis. Heterozygous PAX6 mutation is associated with aniridia and abnormalities of the interhemispheric pathway in humans. We present the case of a 12 year old boy with a known mutation of the PAX6 gene. There were parental concerns regarding his hearing, but repeated pure-tone audiograms were normal. He had a battery of standard central auditory tests, which gave abnormal results in tests which required auditory interhemispheric transfer (dichotic digits and pattern tests). A speech and language assessment, which yielded age-appropriate scores for speech, receptive and expressive language, revealed impaired verbal working memory. These test results were interpreted as indicating impaired auditory sensory and higher order interhemispheric transfer, consistent with reported findings in adults with mutations in PAX6, and correlated with his parent-reported hearing difficulties. This is the first report of central auditory and verbal working memory deficits in a child with a PAX6 mutation. Further research is needed to assess how these deficits impact on academic performance particularly in childhood.
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Affiliation(s)
- Doris-Eva Bamiou
- Academic Unit of Audiological Medicine, Institute of Child Health (UCL), London, UK.
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Rankin PM, Harrison S, Chong WK, Boyd S, Aylett SE. Pyridoxine-dependent seizures: a family phenotype that leads to severe cognitive deficits, regardless of treatment regime. Dev Med Child Neurol 2007; 49:300-5. [PMID: 17376142 DOI: 10.1111/j.1469-8749.2007.00300.x] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The neuropsychological and clinical histories of three male siblings affected by pyridoxine-dependent seizures with known homozygous antiquitin mutations are presented. Neuropsychological evaluation is reported from when the siblings were 11, 9, and 7 years of age. Two of the siblings had received early pyridoxine treatment (antenatal, 2-4 wks into pregnancy) and one had received late treatment (2mo postnatal). However, there was no differential effect on cognitive outcome, with all three siblings having moderate to severe learning disability. Unlike previously reported cases that received early postnatal treatment, none of the siblings had relatively preserved non-verbal cognitive skills. Equally, their intellectual performance over time did not increase above the 1st centile despite high maintenance doses of vitamin B6 (range 16-26 mg/kg/d), and mild sensory neuropathy was reported on nerve conduction studies. The findings in these siblings challenge assumptions that early and high dose pyridoxine treatment can benefit cognition in this population and suggest routine electromyography monitoring may be beneficial.
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Affiliation(s)
- Peter M Rankin
- Developmental Cognitive Neuroscience Unit, Institute of Child Health, University College London, UK.
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Abstract
Neurological impairment is common in resource-poor countries, but its causes are not clear. Computerized tomography (CT) of the brain has been used to determine the cause of brain insults that may manifest as neurological impairments. The authors conducted a community survey in Kilifi of 10 218 children aged 6 to 9 years to detect neurological impairment. From this survey, 34 children were identified, of whom 16 had motor deficits, 11 complex partial seizures, 4 microcephaly or macrocephaly, and 3 severe developmental delay. These children were assessed with elicitation of history, physical examination, and CT scan of the brain. Sixteen (47%) of the scans showed abnormalities: cerebral atrophy (n = 9), schizencephaly (n = 3), periventricular leukomalacia (n = 2), porencephalic cyst (n = 1), and agenesis of the corpus callosum (n = 1). The minimum prevalence of abnormalities on the CT scan of the brain is 1.56 of 1000, and the prevalence of schizencephaly is 0.29 of 1000. Motor impairments were more likely to show abnormality than the other indications. CT abnormalities are common in children with neurological impairment in Kenya, but the appearances did not identify a major cause.
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Affiliation(s)
- P W Njuguna
- Centre for Geographic and Medical Research, Kenya Medical Research Institute, Kilifi, Kenya
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Chan CC, Saunders DE, Chong WK, Hartley BE, Raglan E, Rajput K. Advancement in post-meningitic lateral semicircular canal labyrinthitis ossificans. J Laryngol Otol 2006; 121:105-9. [PMID: 17123454 DOI: 10.1017/s002221510600377x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 06/06/2006] [Indexed: 11/06/2022]
Abstract
Objective: To assess whether lateral semicircular canal (LSCC) ossification is more advanced than that in the cochlear basal turn, in order to judge the value of the former as a predictor.Methods: Retrospective review of 33 paediatric patients from our cochlear implant programme, with profound sensorineural hearing loss after bacterial meningitis. Magnetic resonance imaging (MRI), computed tomography (CT) scans and operative findings were reviewed.Results: On CT, LSCC ossification scores were more advanced than those for the cochlear basal turn in 69.9 per cent of implanted ears. Forty-five per cent (15/33) of children had ossification at surgery. In predicting this, the sensitivity of CT LSCC ossification was 90 per cent and that of MRI LSCC ossification was 83.3 per cent.Conclusions: The more advanced ossification found in the LSCC, compared with that in the cochlear basal turn, adds to previous findings of LSCC pathology predicting cochlear ossification. Surprisingly, CT of the LSCC appears to be no less valuable than MRI in pre-operative cochlear implant assessment of post-meningitic children.
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Affiliation(s)
- C C Chan
- Department of Audiological Medicine, St Ann's Hospital, London, UK
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Prengler M, Pavlakis SG, Boyd S, Connelly A, Calamante F, Chong WK, Saunders D, Cox T, Bynevelt M, Lane R, Laverty A, Kirkham FJ. Sickle cell disease and electroencephalogram hyperventilation. Ann Neurol 2005; 59:214-5. [PMID: 16374826 DOI: 10.1002/ana.20748] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Prengler M, Pavlakis SG, Boyd S, Connelly A, Calamante F, Chong WK, Saunders D, Cox T, Bynevelt M, Lane R, Laverty A, Kirkham FJ. Sickle cell disease: ischemia and seizures. Ann Neurol 2005; 58:290-302. [PMID: 16049936 DOI: 10.1002/ana.20556] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Although the prevalence of seizures in children with sickle cell disease (SCD) is 10 times that of the general population, there are few prospectively collected data on mechanism. With transcranial Doppler and magnetic resonance imaging (MRI) and angiography, we evaluated 76 patients with sickle cell disease, 29 asymptomatic and 47 with neurological complications (seizures, stroke, transient ischemic attack, learning difficulty, headaches, or abnormal transcranial Doppler), who also underwent bolus-tracking perfusion MRI. The six patients with recent seizures also had electroencephalography. Group comparisons (seizure, nonseizure, and asymptomatic) indicated that abnormal transcranial Doppler was more common in the seizure (4/6; 67%) and nonseizure (26/41; 63%) groups than in the asymptomatic (10/29; 34%) group (chi2; p = 0.045), but abnormal structural MRI (chi2; p = 0.7) or magnetic resonance angiography (chi2; p = 0.2) were not. Relative decreased cerebral perfusion was found in all seizure patients and in 16 of 32 of the remaining patients with successful perfusion MRI (p = 0.03). In the seizure patients, the perfusion abnormalities in five were ipsilateral to electroencephalographic abnormalities; one had normal electroencephalogram results. These findings suggest that vasculopathy and focal hypoperfusion may be factors in the development of sickle cell disease-associated seizures.
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Affiliation(s)
- Mara Prengler
- Neurosciences Unit, Institute of Child Health, University College London, London, United Kingdom.
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Sury MRJ, Harker H, Begent J, Chong WK. The management of infants and children for painless imaging. Clin Radiol 2005; 60:731-41. [PMID: 15978882 DOI: 10.1016/j.crad.2005.02.014] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2004] [Revised: 02/15/2005] [Accepted: 02/22/2005] [Indexed: 10/25/2022]
Abstract
The ability of a child to remain sufficiently immobile for painless imaging depends upon their behaviour and the imaging itself. Anaesthesia allows imaging to be optimised but it is expensive, scarce and inappropriate for many situations. Fortunately, sedation and behavioural techniques are sufficiently successful for the majority of scanning, and success rates are high provided that suitable children are selected. Sedation, however, administered by non-anaesthetists, may have catastrophic complications such as airway obstruction. Current UK recommendations demand that any sedation technique has a 'wide margin of safety', but in addition to this, safety is dependent on trained, skillful and experienced staff. Magnetic resonance imaging frightens many children and special planning is necessary for sedation and anaesthesia. When planning an imaging service for children, all the management techniques should be considered in order to achieve maximum efficiency, quality and safety.
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Affiliation(s)
- M R J Sury
- Department of Anaesthesia, Great Ormond Street Hospital for Children NHS Trust, London WC1N 3JH, UK.
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Abstract
Although IQ is thought to remain relatively stable in the normal population, a decline in IQ has been noted in children born preterm. It is not clear, however, to what extent the inclusion of children with clear neurological damage has influenced these findings. We examined IQ scores obtained in childhood and then again in adolescence from a group of children born at 30 weeks gestation or less who had been classified as neurologically normal at 7.5-8 years. They showed a significant decline in mean IQ scores over time. MRI scans obtained from a subset of children at adolescence were read as normal in approximately 50% of cases and, in the others, there were no consistent relationships between radiological abnormalities and IQ results. Such children can, however, have relatively subtle brain abnormalities that are not seen on conventional MRI, and we hypothesized that these would be related to declines in IQ. Voxel-based morphometry (VBM) analyses of the MRI scans revealed that absolute IQ scores were related to areas in both the parietal and temporal lobes. The analyses also showed that frontal and temporal lobe regions were associated with the decline in VIQ, while occipital and temporal lobe regions (including the hippocampi) were associated with the decline in PIQ. Hippocampal volume measurements were consistent with the VBM findings. We concluded that preterm children are at risk of declining IQ over time even if they have not suffered obvious neurological damage and that the decline is associated with specific neural regions. Whether this is true of children born at >30 weeks gestation and what other factors predispose to this decline have yet to be determined.
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Affiliation(s)
- E B Isaacs
- MRC Childhood Nutrition Research Centre, Institute of Child Health, University College London, 30 Guilford Street, London WC1N 1EH, UK.
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Affiliation(s)
- W K Chong
- Department of Radiology, University of North Carolina Hospitals, Chapel Hill, NC 27599-7510, USA.
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