51
|
Tan SY, Jiang J, Ye ZR, Niu XH, Song Y, Zhang CL, Dai PC, Xie BP, Lai XC, Feng DL. Photoemission study of the electronic structure and charge density waves of Na2Ti2Sb2O. Sci Rep 2015; 5:9515. [PMID: 25927621 PMCID: PMC5386208 DOI: 10.1038/srep09515] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2014] [Accepted: 03/02/2015] [Indexed: 12/04/2022] Open
Abstract
The electronic structure of Na2Ti2Sb2O single crystal is studied by photon energy and polarization dependent angle-resolved photoemission spectroscopy (ARPES). The obtained band structure and Fermi surface agree well with the band structure calculation of Na2Ti2Sb2O in the non-magnetic state, which indicates that there is no magnetic order in Na2Ti2Sb2O and the electronic correlation is weak. Polarization dependent ARPES results suggest the multi-band and multi-orbital nature of Na2Ti2Sb2O. Photon energy dependent ARPES results suggest that the electronic structure of Na2Ti2Sb2O is rather two-dimensional. Moreover, we find a density wave energy gap forms below the transition temperature and reaches 65 meV at 7 K, indicating that Na2Ti2Sb2O is likely a weakly correlated CDW material in the strong electron-phonon interaction regime.
Collapse
|
52
|
Bracha A, Tan SY. Robert Bárány (1876–1936): The Nobel Prize-winning prisoner of war. Singapore Med J 2015; 56:5-6. [DOI: 10.11622/smedj.2015002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
|
53
|
Cheah CY, Herbert KE, O'Rourke K, Kennedy GA, George A, Fedele PL, Gilbertson M, Tan SY, Ritchie DS, Opat SS, Prince HM, Dickinson M, Burbury K, Wolf M, Januszewicz EH, Tam CS, Westerman DA, Carney DA, Harrison SJ, Seymour JF. A multicentre retrospective comparison of central nervous system prophylaxis strategies among patients with high-risk diffuse large B-cell lymphoma. Br J Cancer 2014; 111:1072-9. [PMID: 25072255 PMCID: PMC4453849 DOI: 10.1038/bjc.2014.405] [Citation(s) in RCA: 97] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2014] [Revised: 06/04/2014] [Accepted: 06/23/2014] [Indexed: 01/17/2023] Open
Abstract
Background: Central nervous system (CNS) relapse in diffuse large B-cell lymphoma (DLBCL) is a devastating complication; the optimal prophylactic strategy remains unclear. Methods: We performed a multicentre, retrospective analysis of patients with DLBCL with high risk for CNS relapse as defined by two or more of: multiple extranodal sites, elevated serum LDH and B symptoms or involvement of specific high-risk anatomical sites. We compared three different strategies of CNS-directed therapy: intrathecal (IT) methotrexate (MTX) with (R)-CHOP ‘group 1' R-CHOP with IT MTX and two cycles of high-dose intravenous (IV) MTX ‘group 2' dose-intensive systemic antimetabolite-containing chemotherapy (Hyper-CVAD or CODOXM/IVAC) with IT/IV MTX ‘group 3'. Results: Overall, 217 patients were identified (49, 125 and 43 in groups 1–3, respectively). With median follow-up of 3.4 (range 0.2–18.6) years, 23 CNS relapses occurred (12, 10 and 1 in groups 1–3 respectively). The 3-year actuarial rates (95% CI) of CNS relapse were 18.4% (9.5–33.1%), 6.9% (3.5–13.4%) and 2.3% (0.4–15.4%) in groups 1–3, respectively (P=0.009). Conclusions: The addition of high-dose IV MTX and/or cytarabine was associated with lower incidence of CNS relapse compared with IT chemotherapy alone. However, these data are limited by their retrospective nature and warrant confirmation in prospective randomised studies.
Collapse
|
54
|
Jiang J, Li S, Zhang T, Sun Z, Chen F, Ye ZR, Xu M, Ge QQ, Tan SY, Niu XH, Xia M, Xie BP, Li YF, Chen XH, Wen HH, Feng DL. Observation of possible topological in-gap surface states in the Kondo insulator SmB6 by photoemission. Nat Commun 2014; 4:3010. [PMID: 24346657 PMCID: PMC3905704 DOI: 10.1038/ncomms4010] [Citation(s) in RCA: 227] [Impact Index Per Article: 22.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2013] [Accepted: 11/26/2013] [Indexed: 11/13/2022] Open
Abstract
SmB6, a well-known Kondo insulator, exhibits a transport anomaly at low temperature. This anomaly is usually attributed to states within the hybridization gap. Recent theoretical work and transport measurements suggest that these in-gap states could be ascribed to topological surface states, which would make SmB6 the first realization of topological Kondo insulator. Here by performing angle-resolved photoemission spectroscopy experiments, we directly observe several dispersive states within the hybridization gap of SmB6. These states show negligible kz dependence, which indicates their surface origin. Furthermore, we perform photoemission circular dichroism experiments, which suggest that the in-gap states possess chirality of the orbital angular momentum. These states vanish simultaneously with the hybridization gap at around 150 K. Together, these observations suggest the possible topological origin of the in-gap states. The Kondo insulator samarium hexaboride exhibits low-temperature transport anomalies, which might be due to topological surface states. Here Jiang et al. perform angle-resolved photoemission and its circular dichroism measurements, which suggest that the anomalies might be of topological origin.
Collapse
|
55
|
Peng R, Shen XP, Xie X, Xu HC, Tan SY, Xia M, Zhang T, Cao HY, Gong XG, Hu JP, Xie BP, Feng DL. Measurement of an enhanced superconducting phase and a pronounced anisotropy of the energy gap of a strained FeSe single layer in FeSe/Nb:SrTiO3/KTaO3 heterostructures using photoemission spectroscopy. PHYSICAL REVIEW LETTERS 2014; 112:107001. [PMID: 24679321 DOI: 10.1103/physrevlett.112.107001] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/11/2013] [Indexed: 06/03/2023]
Abstract
Single-layer FeSe films with an extremely expanded in-plane lattice constant of 3.99±0.02 Å are fabricated by epitaxially growing FeSe/Nb:SrTiO3/KTaO3 heterostructures and studied by in situ angle-resolved photoemission spectroscopy. Two elliptical electron pockets at the Brillouin zone corner are resolved with negligible hybridization between them, indicating that the symmetry of the low-energy electronic structure remains intact as a freestanding single-layer FeSe, although it is on a substrate. The superconducting gap closes at a record high temperature of 70 K for the iron-based superconductors. Intriguingly, the superconducting gap distribution is anisotropic but nodeless around the electron pockets, with minima at the crossings of the two pockets. Our results place strong constraints on current theories.
Collapse
|
56
|
Krishnan S, Sabai K, Chuah C, Tan SY. Bilineal T lymphoblastic and myeloid blast transformation in chronic myeloid leukemia with TP53 mutation-an uncommon presentation in adults. ACTA ACUST UNITED AC 2014; 21:e147-50. [PMID: 24523612 DOI: 10.3747/co.21.1660] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Bilineal blast transformation of myeloid and T lymphoid type is a rare event in chronic myeloid leukemia. Here, we report a case in which an adult presented with high white cell counts and lymphadenopathy. Bone marrow studies confirmed the presence of 9 and 22 chromosomal translocation, and a diagnosis of chronic myeloid leukemia in chronic phase was made. Examination of a lymph node showed both myeloid and T lymphoblastoid blast crisis. Molecular studies demonstrated the presence of BCR-ABL fusion transcripts in both the myeloid and the T lymphoblastic component, indicating that the myeloid and T lymphoid blast crisis components shared common progenitors. TP53 deletion was demonstrated by fluorescence in situ hybridization.
Collapse
|
57
|
Tan SY, Tatsumura Y. Albert Schweitzer (1875–1965): A reverence for life. Singapore Med J 2014; 55:351-2. [DOI: 10.11622/smedj.2014084] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
|
58
|
Tan SY, Mattes RD. Appetitive, dietary and health effects of almonds consumed with meals or as snacks: a randomized, controlled trial. Eur J Clin Nutr 2013; 67:1205-14. [PMID: 24084509 PMCID: PMC3898316 DOI: 10.1038/ejcn.2013.184] [Citation(s) in RCA: 122] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2013] [Revised: 07/25/2013] [Accepted: 08/28/2013] [Indexed: 11/09/2022]
Abstract
BACKGROUND/OBJECTIVES Snacks contribute toward a significant proportion of human total daily energy intake. This study investigated the effects of almonds, a satiating and nutrient-rich, common snack, on postprandial glycemia, appetite, short-term body weight and fasting blood parameters when consumed with meals or alone as a snack. METHODS This was a 4-week randomized, parallel-arm study that entailed consuming almonds (43 g/day) with breakfast (BF) or lunch (LN), alone as a morning (MS) or afternoon (AS) snack or no almonds (CL). Participants (N=137) with increased risk for type 2 diabetes completed an oral glucose tolerance test (OGTT) and acute-feeding session at baseline, followed by almond consumption for 4 weeks before repeating the OGTT and acute-feeding trials. Anthropometric, biochemical and appetite responses were assessed. RESULTS Almonds lowered serum glucose responses postprandially. Effects were most prominent in the snack groups. Almonds, consumed as snacks, also reduced hunger and desire to eat during the acute-feeding session. After 4 weeks, anthropometric measurements and fasting blood biochemistries did not differ from the control group or across intervention groups. Without specific guidance, daily energy intake was reduced to compensate for energy from the provided almonds. Dietary monounsaturated fat and α-tocopherol intakes were significantly increased in all almond groups. CONCLUSION Almonds provide post-ingestive metabolic and appetitive benefits and did not increase the risk for weight gain. This suggests that almonds may be a healthful snack option.
Collapse
|
59
|
Tan SY, Stevens MJ, Mueller CM. A Novel Laparoscopic-Assisted Approach to the Repair of Pediatric Femoral Hernias. J Laparoendosc Adv Surg Tech A 2013; 23:946-8. [DOI: 10.1089/lap.2013.0199] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
|
60
|
|
61
|
Peng WJ, Yan FP, Li Q, Liu S, Feng T, Tan SY, Feng SC. 1.94 μm switchable dual-wavelength Tm3+ fiber laser employing high-birefringence fiber Bragg grating. APPLIED OPTICS 2013; 52:4601-4607. [PMID: 23842257 DOI: 10.1364/ao.52.004601] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/18/2013] [Accepted: 05/23/2013] [Indexed: 06/02/2023]
Abstract
A 1.94 μm switchable dual-wavelength Tm(3+) fiber laser employing two high-birefringence fiber Bragg gratings (HB-FBGs) is demonstrated. The polarization hole burning effect enhanced by the HB-FBG is first observed and adopted to guarantee stable dual-wavelength operation in the spectral region near 2 μm at room temperature. The wavelength spacing between the dual lasing wavelengths is 0.81 nm. The polarization states of the dual-output lasers are orthogonal. By adjusting a polarization controller, a single-wavelength mode operating at one of the dual wavelengths can be selected. The side-mode-suppression ratio of each laser can be greater than 60 dB. The power fluctuation measurement at both operating wavelengths shows that this Tm(3+) fiber laser has good stability.
Collapse
|
62
|
Oh ML, Tan SY. P054: Prevalence and risk factor analysis for methicillin-resistant Staphylococcus aureus colonization in an acute care hospital. Antimicrob Resist Infect Control 2013. [PMCID: PMC3688521 DOI: 10.1186/2047-2994-2-s1-p54] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
|
63
|
Tan SY, Poh BK, Nadrah MH, Jannah NA, Rahman J, Ismail MN. Nutritional status and dietary intake of children with acute leukaemia during induction or consolidation chemotherapy. J Hum Nutr Diet 2013; 26 Suppl 1:23-33. [PMID: 23701375 DOI: 10.1111/jhn.12074] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
BACKGROUND The assessment of nutritional status among paediatric patients is important for the planning and execution of nutritional strategies that strive to optimise the quality of life and growth among sick children. The present study aimed to evaluate the nutritional status and dietary intake among children with acute leukaemia. METHODS This cross-sectional study included 53 paediatric patients aged 3-12 years old, who were diagnosed with either acute lymphoblastic leukaemia or acute myelogenous leukaemia and were undergoing chemotherapy treatments (induction or consolidation phase). Patients were matched for sex, age (±6 months) and ethnicity with healthy children as controls. Weight, height, body mass index, waist circumference, mid-upper arm circumference, triceps skinfold thickness, mid-upper arm muscle area and fat area were determined. Dietary intake was assessed using 3-day food records. RESULTS Anthropometric variables were generally higher among patients compared to controls, although the differences were not statistically significant (P > 0.05). The prevalence of overnutrition among patients according to body mass index-for-age, waist circumference-for-age, mid-upper arm circumference-for-age and triceps skinfold-for-age were 24.5%, 29.1%, 17.0% and 30.2%, respectively. Mean energy [5732 ± 1958 kJ (1370 ± 468 kcal) versus 6945 ± 1970 kJ (1660 ± 471 kcal), P < 0.01], protein (50.0 ± 19.7 g versus 62.3 ± 22.3 g, P < 0.01) and fat (43.6 ± 18.9 g versus 58.3 ± 16.7, P < 0.001) intakes of patients were significantly lower than controls. CONCLUSIONS The prevalence of being overweight and obesity in children with acute leukaemia was higher despite lower energy intake compared to controls. Studies assessing physical activity, the complex interaction and the effects of treatment drugs are warranted to better manage malnutrition among paediatric patients.
Collapse
|
64
|
Tan SY, Graham C. Karl Landsteiner (1868–1943): Originator of ABO blood classification. Singapore Med J 2013; 54:243-4. [DOI: 10.11622/smedj.2013099] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
|
65
|
Tan SY, Furubayashi JK. The Mayo brothers (William James Mayo 1861-1939, Charles Horace Mayo 1865-1939): pioneers of group surgical practice. Singapore Med J 2012; 53:157-158. [PMID: 22434286] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
|
66
|
Kotresha D, Poonam D, Muhammad Hafiznur Y, Saadatnia G, Nurulhasanah O, Sabariah O, Tan SY, Izzati Zahidah AK, Rahmah N. Recombinant proteins from new constructs of SAG1 and GRA7 sequences and their usefulness to detect acute toxoplasmosis. Trop Biomed 2012; 29:129-137. [PMID: 22543613] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
In this study we have cloned unreported gene fragments of Toxoplasma gondii GRA7 and SAG1 and expressed the corresponding recombinant proteins, followed by evaluation of their usefulness for the serological diagnosis of toxoplasmosis. Both recombinant proteins were expressed efficiently in insoluble form, purified by single step Ni-NTA affinity chromatography and their antigenicity to detect toxoplasma specific IgG antibodies were determined by immunoblotting. A total of 60 serum samples from three groups of individuals based on their anti-toxoplasma antibody profiles were tested, namely (I) IgM+, IgG+ (n=20), (II) IgM-, IgG+ (n=20) and (III) IgM-, IgG- (n=20). Both recombinant proteins exhibited high sensitivity (100%) with sera from Group I. rGRA7 and rSAG1 reacted 40% and 80% respectively with Group II sera. The specificity of the recombinant proteins based on reactivities with Group III sera were 100% and 80% with rGRA7 and rSAG1 respectively. Thus rGRA7 was found to be better at discriminating probable acute from chronic phases of toxoplasmosis, and it also showed higher specificity.
Collapse
|
67
|
Merritt C, Tan SY. Willem Einthoven (1860-1927): father of electrocardiography. Singapore Med J 2012; 53:17-18. [PMID: 22252177] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
|
68
|
Tan SY, Linskey K. Niels Finsen (1860-1904): Gift of light. Singapore Med J 2011; 52:777-778. [PMID: 22173245] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
|
69
|
Merritt C, Tan SY. Medicine in stamps. Christiaan Eijkman (1858-1930): the vicar of vitamins. Singapore Med J 2011; 52:652-653. [PMID: 21947140] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
|
70
|
Dworkin J, Tan SY. Medicine in stamps. Ronald Ross (1857-1932): discoverer of malaria's life cycle. Singapore Med J 2011; 52:466-467. [PMID: 21808954] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
|
71
|
Tan SY, Takeyesu A. Sigmund Freud (1856-1939): father of psychoanalysis. Singapore Med J 2011; 52:322-323. [PMID: 21633763] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
|
72
|
Tan SY, Davis C. David Bruce (1855-1931): discoverer of brucellosis. Singapore Med J 2011; 52:138-139. [PMID: 21451919] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
|
73
|
Ng CT, Htoo A, Tan SY. Fish bone-induced hepatic abscess: medical treatment. Singapore Med J 2011; 52:e56-e58. [PMID: 21451917] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
We report a case of a 59-year-old man admitted for acute myocardial infarction. He subsequently spiked a high-grade fever on the second day after percutaneous coronary intervention. Computed tomography imaging of the abdomen revealed a hepatic abscess secondary to gastrointestinal perforation by a fish bone. Medical therapy with antibiotics was preferred over surgical drainage of the hepatic abscess in view of the fact that the patient was on dual antiplatelet agents. The hepatic abscess was completely resolved with conservative antimicrobial therapy. Antimicrobial therapy appears to be a viable option in selected patients with hepatic abscess secondary to fish bone perforation, especially if they have contraindications to surgery.
Collapse
|
74
|
Bracha A, Tan SY. Emil von Behring (1854-1917): Medicine's first Nobel laureate. Singapore Med J 2011; 52:1-2. [PMID: 21298232] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
|
75
|
Abstract
This article reviews the elements of medical malpractice, informed consent, and affirmative defense; and discusses the legal risks associated with the diagnosis and therapy of cardiovascular disease.
Collapse
|