26
|
Chen CT, Chang CC, Chang WN, Tsai NW, Huang CC, Chang YT, Wang HC, Kung CT, Su YJ, Lin WC, Cheng BC, Su CM, Hsiao SY, Hsu CW, Lu CH. Neuropsychiatric symptoms in Alzheimer's disease: associations with caregiver burden and treatment outcomes. QJM 2017; 110:565-570. [PMID: 28383687 DOI: 10.1093/qjmed/hcx077] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/24/2016] [Indexed: 11/15/2022] Open
Abstract
BACKGROUND Caregivers play a major role in providing care for patients with Alzheimer's disease (AD) and are themselves at higher risk of health comorbidities. AIM To address the impact of neuropsychiatric symptoms of patients in different stages of AD on their caregivers' burden. DESIGN This prospective study enrolled 260 AD patients with clinical dementia rating (CDR) of 0.5, 1 and 2 at a tertiary medical center. METHODS All patients were tested using the mini-mental state examination (MMSE), the cognitive abilities screening instrument (CASI), the neuropsychiatric inventory (NPI) and the CDR scale. Data regarding therapeutic outcomes of anti-Alzheimer's drugs were also collected. Caregivers were tested using NPI. RESULTS The mean follow-up interval was 25.0 ± 12.2 months, and two patients died during follow-up. NPI-burden was positively correlated with NPI-sum ( r = 0.822, P < 0.001) but negatively correlated with years of education ( r = -0.140, P = 0.024), CASI score ( r = -0.259, P < 0.001) and MMSE score ( r = -0.262, P <0.001). Multiple linear regression analysis showed that only NPI-sum was independently associated with mean NPI-burden. Both higher mean CASI and MMSE scores had better therapeutic outcome of anti-Alzheimer's drugs ( P = 0.001 and P = 0.005, respectively). CONCLUSIONS The severity of neuropsychiatric symptoms in patients with AD was positively associated with caregiver's stress, and patients with better cognitive functions, under treatment with anti-Alzheimer's drugs, had better therapeutic outcomes. To reduce the impact of neuropsychiatric symptoms, it is crucial to detect dementia in its early phases and provide early intervention with anti-Alzheimer's drugs, which might help decrease the caregiver burden, thereby improving their quality of life.
Collapse
|
27
|
Huang HY, Chen ZY, Wang RP, de Groot FMF, Wu WB, Okamoto J, Chainani A, Singh A, Li ZY, Zhou JS, Jeng HT, Guo GY, Park JG, Tjeng LH, Chen CT, Huang DJ. Jahn-Teller distortion driven magnetic polarons in magnetite. Nat Commun 2017; 8:15929. [PMID: 28660878 PMCID: PMC5493765 DOI: 10.1038/ncomms15929] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2017] [Accepted: 05/12/2017] [Indexed: 11/20/2022] Open
Abstract
The first known magnetic mineral, magnetite, has unusual properties, which have fascinated mankind for centuries; it undergoes the Verwey transition around 120 K with an abrupt change in structure and electrical conductivity. The mechanism of the Verwey transition, however, remains contentious. Here we use resonant inelastic X-ray scattering over a wide temperature range across the Verwey transition to identify and separate out the magnetic excitations derived from nominal Fe2+ and Fe3+ states. Comparison of the experimental results with crystal-field multiplet calculations shows that the spin–orbital dd excitons of the Fe2+ sites arise from a tetragonal Jahn-Teller active polaronic distortion of the Fe2+O6 octahedra. These low-energy excitations, which get weakened for temperatures above 350 K but persist at least up to 550 K, are distinct from optical excitations and are best explained as magnetic polarons. The Verwey transition of magnetite is complex due to the coexistence of strong correlations and electron-phonon coupling. Here, the authors use resonant inelastic X-ray scattering to show evidence for magnetic polarons in magnetite and provide insight into the nature of the transition.
Collapse
|
28
|
Chen HY, Lin CW, Chen CT, Chen CT, Golder J, Lan YB, Wang JK. Polymer side-chain substituents elucidate thermochromism of benzodithiophene–dithiophenylacrylonitrile copolymers – polymer solubility correlation of thermochromism and photovoltaic performance. Polym Chem 2017. [DOI: 10.1039/c7py00338b] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
pBCNx polymers with different side-chain substituents for thermochromism and photovoltaic studies.
Collapse
|
29
|
Chen LC, Chen CC, Liang KC, Chang SH, Tseng ZL, Yeh SC, Chen CT, Wu WT, Wu CG. Nano-structured CuO-Cu2O Complex Thin Film for Application in CH3NH3PbI3 Perovskite Solar Cells. NANOSCALE RESEARCH LETTERS 2016; 11:402. [PMID: 27637894 PMCID: PMC5025402 DOI: 10.1186/s11671-016-1621-4] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/10/2016] [Accepted: 09/07/2016] [Indexed: 05/14/2023]
Abstract
Nano-structured CuO-Cu2O complex thin film-based perovskite solar cells were fabricated on an indium tin oxide (ITO)-coated glass and studied. Copper (Cu) thin films with a purity of 99.995 % were deposited on an ITO-coated glass by magnetron reactive sputtering. To optimize the properties of the nano-structured CuO-Cu2O complex thin films, the deposited Cu thin films were thermally oxidized at various temperatures from 300 to 400 °C. A CH3NH3PbI3 perovskite absorber was fabricated on top of CuO-Cu2O complex thin film by a one-step spin-coating process with a toluene washing treatment. Following optimization, the maximum power conversion efficiency (PCE) exceeded 8.1 %. Therefore, the low-cost, solution-processed, stable nano-structured CuO-Cu2O complex thin film can be used as an alternative hole transport layer (HTL) in industrially produced perovskite solar cells.
Collapse
|
30
|
Hsu YY, Yeh SC, Lin SH, Chen CT, Tung SH, Jeng RJ. Dendrons with urea/malonamide linkages for gate insulators of n-channel organic thin film transistors. REACT FUNCT POLYM 2016. [DOI: 10.1016/j.reactfunctpolym.2016.05.008] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
|
31
|
Fabbris G, Meyers D, Okamoto J, Pelliciari J, Disa AS, Huang Y, Chen ZY, Wu WB, Chen CT, Ismail-Beigi S, Ahn CH, Walker FJ, Huang DJ, Schmitt T, Dean MPM. Orbital Engineering in Nickelate Heterostructures Driven by Anisotropic Oxygen Hybridization rather than Orbital Energy Levels. PHYSICAL REVIEW LETTERS 2016; 117:147401. [PMID: 27740843 DOI: 10.1103/physrevlett.117.147401] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/17/2016] [Indexed: 06/06/2023]
Abstract
Resonant inelastic x-ray scattering is used to investigate the electronic origin of orbital polarization in nickelate heterostructures taking LaTiO_{3}-LaNiO_{3}-3×(LaAlO_{3}), a system with exceptionally large polarization, as a model system. We find that heterostructuring generates only minor changes in the Ni 3d orbital energy levels, contradicting the often-invoked picture in which changes in orbital energy levels generate orbital polarization. Instead, O K-edge x-ray absorption spectroscopy demonstrates that orbital polarization is caused by an anisotropic reconstruction of the oxygen ligand hole states. This provides an explanation for the limited success of theoretical predictions based on tuning orbital energy levels and implies that future theories should focus on anisotropic hybridization as the most effective means to drive large changes in electronic structure and realize novel emergent phenomena.
Collapse
|
32
|
Lee YT, Chang YT, Wu CL, Golder J, Chen CT, Chen CT. SimCP3—An Advanced Homologue of SimCP2 as a Solution-Processed Small Molecular Host Material for Blue Phosphorescence Organic Light-Emitting Diodes. Molecules 2016; 21:molecules21101315. [PMID: 27706060 PMCID: PMC6273694 DOI: 10.3390/molecules21101315] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2016] [Revised: 09/24/2016] [Accepted: 09/27/2016] [Indexed: 11/16/2022] Open
Abstract
We have overcome the synthetic difficulty of 9,9′,9′′,9′′′,9′′′′,9′′′′′-((phenylsilanetriyl)tris(benzene-5,3,1-triyl))hexakis(9H-carbazole) (SimCP3) an advanced homologue of previously known SimCP2 as a solution-processed, high triplet gap energy host material for a blue phosphorescence dopant. A series of organic light-emitting diodes based on blue phosphorescence dopant iridium (III) bis(4,6-difluorophenylpyridinato)picolate, FIrpic, were fabricated and tested to demonstrate the validity of solution-processed SimCP3 in the device fabrication.
Collapse
|
33
|
Huang HY, Jia CJ, Chen ZY, Wohlfeld K, Moritz B, Devereaux TP, Wu WB, Okamoto J, Lee WS, Hashimoto M, He Y, Shen ZX, Yoshida Y, Eisaki H, Mou CY, Chen CT, Huang DJ. Raman and fluorescence characteristics of resonant inelastic X-ray scattering from doped superconducting cuprates. Sci Rep 2016; 6:19657. [PMID: 26794437 PMCID: PMC4726252 DOI: 10.1038/srep19657] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2015] [Accepted: 12/15/2015] [Indexed: 11/23/2022] Open
Abstract
Measurements of spin excitations are essential for an understanding of spin-mediated pairing for superconductivity; and resonant inelastic X-ray scattering (RIXS) provides a considerable opportunity to probe high-energy spin excitations. However, whether RIXS correctly measures the collective spin excitations of doped superconducting cuprates remains under debate. Here we demonstrate distinct Raman- and fluorescence-like RIXS excitations of Bi1.5Pb0.6Sr1.54CaCu2O8+δ. Combining photon-energy and momentum dependent RIXS measurements with theoretical calculations using exact diagonalization provides conclusive evidence that the Raman-like RIXS excitations correspond to collective spin excitations, which are magnons in the undoped Mott insulators and evolve into paramagnons in doped superconducting compounds. In contrast, the fluorescence-like shifts are due primarily to the continuum of particle-hole excitations in the charge channel. Our results show that under the proper experimental conditions RIXS indeed can be used to probe paramagnons in doped high-Tc cuprate superconductors.
Collapse
|
34
|
Huang PT, Chou CW, Lin BY, Shi ZE, Huang YJ, Chen CT, Cheng CH, Wang JK. Controlling the morphology of poly(3-hexylthiophene)/methanofullerene film through a dynamic-cooling and freeze-drying process. POLYM INT 2015. [DOI: 10.1002/pi.5028] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
|
35
|
Chen CT, Poloek A, Wang C, Lin CW, Chen CT. Solid state molecular packing and photoluminescence of platinum complexes based on 1,5-naphthyridin-4-olate ligands. Acta Crystallogr A Found Adv 2015. [DOI: 10.1107/s2053273315095066] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
|
36
|
Chen HY, Golder J, Yeh SC, Lin CW, Chen CT, Chen CT. Diindeno[1,2-g:1′,2′-s]rubicene: all-carbon non-fullerene electron acceptor for efficient bulk-heterojunction organic solar cells with high open-circuit voltage. RSC Adv 2015. [DOI: 10.1039/c4ra12505c] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
An all carbon non-fullerene electron acceptor material based on diindeno[1,2-g:1′,2′-s]rubicene (DIR) was readily synthesized and processed for bulk-heterojunction organic solar cells.
Collapse
|
37
|
Wu CL, Chen CT, Chen CT. Synthesis and Characterization of Heteroatom-Bridged Bis-spirobifluorenes for the Application of Organic Light-Emitting Diodes. Org Lett 2014; 16:2114-7. [DOI: 10.1021/ol5005214] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
|
38
|
Sonar P, Ha TJ, Seong Y, Yeh SC, Chen CT, Manzhos S, Dodabalapur A. A Study of Diphenylfumaronitrile and Furan-Substituted Diketopyrrolopyrrole Alternating Copolymer and Its Thin-Film Transistors. MACROMOL CHEM PHYS 2014. [DOI: 10.1002/macp.201300588] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
|
39
|
Lai CH, Fung HS, Wu WB, Huang HY, Fu HW, Lin SW, Huang SW, Chiu CC, Wang DJ, Huang LJ, Tseng TC, Chung SC, Chen CT, Huang DJ. Highly efficient beamline and spectrometer for inelastic soft X-ray scattering at high resolution. JOURNAL OF SYNCHROTRON RADIATION 2014; 21:325-332. [PMID: 24562553 DOI: 10.1107/s1600577513030877] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2013] [Accepted: 11/10/2013] [Indexed: 06/03/2023]
Abstract
The design, construction and commissioning of a beamline and spectrometer for inelastic soft X-ray scattering at high resolution in a highly efficient system are presented. Based on the energy-compensation principle of grating dispersion, the design of the monochromator-spectrometer system greatly enhances the efficiency of measurement of inelastic soft X-rays scattering. Comprising two bendable gratings, the set-up effectively diminishes the defocus and coma aberrations. At commissioning, this system showed results of spin-flip, d-d and charge-transfer excitations of NiO. These results are consistent with published results but exhibit improved spectral resolution and increased efficiency of measurement. The best energy resolution of the set-up in terms of full width at half-maximum is 108 meV at an incident photon energy tuned about the Ni L3-edge.
Collapse
|
40
|
Mejia J, Reis MA, Miranda ACC, Batista IR, Barboza MRF, Shih MC, Fu G, Chen CT, Meng LJ, Bressan RA, Amaro E. Performance assessment of the single photon emission microscope: high spatial resolution SPECT imaging of small animal organs. Braz J Med Biol Res 2013; 46:936-942. [PMID: 24270908 PMCID: PMC3854337 DOI: 10.1590/1414-431x20132764] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2012] [Accepted: 08/21/2013] [Indexed: 01/12/2023] Open
Abstract
The single photon emission microscope (SPEM) is an instrument developed to obtain
high spatial resolution single photon emission computed tomography (SPECT) images of
small structures inside the mouse brain. SPEM consists of two independent imaging
devices, which combine a multipinhole collimator, a high-resolution, thallium-doped
cesium iodide [CsI(Tl)] columnar scintillator, a demagnifying/intensifier tube, and
an electron-multiplying charge-coupling device (CCD). Collimators have 300- and
450-µm diameter pinholes on tungsten slabs, in hexagonal arrays of 19 and 7 holes.
Projection data are acquired in a photon-counting strategy, where CCD frames are
stored at 50 frames per second, with a radius of rotation of 35 mm and magnification
factor of one. The image reconstruction software tool is based on the maximum
likelihood algorithm. Our aim was to evaluate the spatial resolution and sensitivity
attainable with the seven-pinhole imaging device, together with the linearity for
quantification on the tomographic images, and to test the instrument in obtaining
tomographic images of different mouse organs. A spatial resolution better than 500 µm
and a sensitivity of 21.6 counts·s-1·MBq-1 were reached, as
well as a correlation coefficient between activity and intensity better than 0.99,
when imaging 99mTc sources. Images of the thyroid, heart, lungs, and bones
of mice were registered using 99mTc-labeled radiopharmaceuticals in times
appropriate for routine preclinical experimentation of <1 h per projection data
set. Detailed experimental protocols and images of the aforementioned organs are
shown. We plan to extend the instrument's field of view to fix larger animals and to
combine data from both detectors to reduce the acquisition time or applied
activity.
Collapse
|
41
|
Chang YT, Chang JK, Lee YT, Wang PS, Wu JL, Hsu CC, Wu IW, Tseng WH, Pi TW, Chen CT, Wu CI. High-efficiency small-molecule-based organic light emitting devices with solution processes and oxadiazole-based electron transport materials. ACS APPLIED MATERIALS & INTERFACES 2013; 5:10614-10622. [PMID: 24138603 DOI: 10.1021/am402504g] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
We demonstrate high-efficiency small-molecule-based white phosphorescent organic light emitting diodes (PHOLEDs) by single-active-layer solution-based processes with the current efficiency of 17.3 cdA(-1) and maximum luminous efficiency of 8.86 lmW(-1) at a current density of 1 mA cm(-2). The small-molecule based emitting layers are codoped with blue and orange phosphorescent dyes. We show that the presence of CsF/Al at cathodes not only improves electron transport in oxadiazole-containing electron transport layers (ETLs), but also facilitates electron injection through the reacted oxadiazole moiety to reduce interface resistance, which results in the enhancement of current efficiency. By selecting oxadiazole-based materials as ETLs with proper electron injection layer (EIL)/cathode structures, the brightness and efficiency of white PHOLEDs are significantly improved.
Collapse
|
42
|
Chiang CL, Wen YJ, Wen YS, Shu CF, Chen CT. Synthesis and Characterization of Donor-Acceptor-Substituted Fluorene Fluorophores for Non-Doped Red Organic Light Emitting Diodes. J CHIN CHEM SOC-TAIP 2013. [DOI: 10.1002/jccs.200600177] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
|
43
|
Chen CT, Cha I, Hsieh SJ. Thermal Stability of Robust Unsymmetrical Copperporphyrins with Multiple Diphenylamino and Nitro Substituents. J CHIN CHEM SOC-TAIP 2013. [DOI: 10.1002/jccs.199800111] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
|
44
|
|
45
|
Chen CT, Lin TYJ, Chen CH, Lin KJ. Molecular Nonlinear Optical Properties of Acceptors Substituted 2,2′-Bipyridine and 1,10-Phenathroline Complexes of Nickel Dithiolate. J CHIN CHEM SOC-TAIP 2013. [DOI: 10.1002/jccs.200000023] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
|
46
|
Wang CC, Wu WC, Lee GH, Chen CT. Structures and UV-Visible Absorption Properties of Unsymmetrical Bisdithiolene Nickel Complexes. J CHIN CHEM SOC-TAIP 2013. [DOI: 10.1002/jccs.200200115] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
|
47
|
Hong CF, Hsieh HY, Chen CT, Huang HC. Development of a Semiselective Medium for Detection of Nalanthamala psidii, Causal Agent of Wilt of Guava. PLANT DISEASE 2013; 97:1132-1136. [PMID: 30722420 DOI: 10.1094/pdis-12-12-1193-re] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Guava wilt, caused by Nalanthamala psidii, has become an important disease of guava (Psidium guajava) in Taiwan since the 1970s. This study was conducted to develop a semiselective medium for detecting N. psidii in soil and in tissues of diseased guava trees. Among 9 carbon and 21 nitrogen compounds tested in a modified Czapek-Dox medium, the most effective carbon and nitrogen sources for mycelial growth of N. psidii were sucrose and glycine, respectively. Among eight fungicides tested, iprodione at 5 μg ml-1 and azoxystrobin at 1 μg ml-1 were the most effective fungicides for detection of N. psidii in artificially infested soil or in naturally infected guava debris. Based on the requirement for carbon and nitrogen sources and response to fungicides, a semiselective medium designated as modified sucrose-glycine semiselective medium (mSGSSM) was developed for isolation of N. psidii, using the modified Czapek-Dox medium containing 3% sucrose, 0.3% glycine, iprodione at 5 μg ml-1, azoxystrobin at 1 μg ml-1, streptomycin at 200 μg ml-1, and neomycin at 200 μg ml-1. Colonies of N. psidii on mSGSSM at 30°C for 5 to 10 days were white to orange with sparse aerial hyphae. N. psidii was detected more accurately and efficiently on mSGSSM than on other media, including potato dextrose agar, modified Nash-Snyder medium, and modified Czapek-Dox medium. This semiselective medium is effective in detection of N. psidii from various parts of diseased guava trees and in soil; therefore, it would be a useful medium for etiological, ecological, and epidemiological studies of guava wilt.
Collapse
|
48
|
Nie SH, Chin YY, Liu WQ, Tung JC, Lu J, Lin HJ, Guo GY, Meng KK, Chen L, Zhu LJ, Pan D, Chen CT, Xu YB, Yan WS, Zhao JH. Ferromagnetic interfacial interaction and the proximity effect in a Co2FeAl/(Ga,Mn)As bilayer. PHYSICAL REVIEW LETTERS 2013; 111:027203. [PMID: 23889435 DOI: 10.1103/physrevlett.111.027203] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2013] [Indexed: 06/02/2023]
Abstract
The magnetic properties of a Co2FeAl/(Ga,Mn)As bilayer epitaxied on GaAs (001) are studied both experimentally and theoretically. Unlike the common antiferromagnetic interfacial interaction existing in most ferromagnet-magnetic semiconductor bilayers, a ferromagnetic interfacial interaction in the Co2FeAl/(Ga,Mn)As bilayer is observed from measurements of magnetic hysteresis and x-ray magnetic circular dichroism. The Mn ions in a 1.36 nm thick (Ga,Mn)As layer remain spin polarized up to 400 K due to the magnetic proximity effect. The minor loops of the Co2FeAl/(Ga,Mn)As bilayer shift with a small ferromagnetic interaction field of +24 Oe and -23 Oe at 15 K. The observed ferromagnetic interfacial coupling is supported by ab initio density functional calculations. These findings may provide a viable pathway for designing room-temperature semiconductor spintronic devices through magnetic proximity effect.
Collapse
|
49
|
Yang JC, He Q, Suresha SJ, Kuo CY, Peng CY, Haislmaier RC, Motyka MA, Sheng G, Adamo C, Lin HJ, Hu Z, Chang L, Tjeng LH, Arenholz E, Podraza NJ, Bernhagen M, Uecker R, Schlom DG, Gopalan V, Chen LQ, Chen CT, Ramesh R, Chu YH. Orthorhombic BiFeO3. PHYSICAL REVIEW LETTERS 2012; 109:247606. [PMID: 23368382 DOI: 10.1103/physrevlett.109.247606] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2012] [Revised: 09/07/2012] [Indexed: 05/12/2023]
Abstract
A new orthorhombic phase of the multiferroic BiFeO3 has been created via strain engineering by growing it on a NdScO(3)(110)(o) substrate. The tensile-strained orthorhombic BiFeO3 phase is ferroelectric and antiferromagnetic at room temperature. A combination of nonlinear optical second harmonic generation and piezoresponse force microscopy revealed that the ferroelectric polarization in the orthorhombic phase is along the in-plane {110}(pc) directions. In addition, the corresponding rotation of the antiferromagnetic axis in this new phase was observed using x-ray linear dichroism.
Collapse
|
50
|
Chen CT, Au JL, Gan Y, Guillaume Wientjes M. Differential time dependency of antiproliferative and apoptotic effects of taxol in human prostate tumors. Urol Oncol 2012; 3:11-7. [PMID: 21227047 DOI: 10.1016/s1078-1439(97)00016-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The pharmacodynamics of taxol in human prostate tumors were studied using histocultures of radical prostatectomy specimens from 34 patients. The results showed that taxol inhibited DNA synthesis and induced apoptosis in all tumors. The taxol-induced DNA inhibition and the apoptotic index increased with drug concentration, but reached a maximal plateau level at a concentration between 120 and 1,200 nM. Increasing the concentration by 10- to 100-fold to 12,000 nM did not significantly increase either effect. To address the existing controversy regarding the effect of treatment duration on cytotoxicity, we evaluated two treatment schedules, (i.e., 24 and 96 hours). Prolonging the treatment time from 24 to 96 hours significantly increased the average maximal inhibition of DNA synthesis (E(max)) from 47% to 70% (p < 0.001) and reduced the incidence of relatively resistant tumors (E(max) < 30%) from 31% to 0% (p = 0.04). By contrast, the prolonged treatment time did not increase the apoptotic effect (p = 0.48). The inter-tumor variation in sensitivity to the antiproliferative effect was substantial; the drug concentration required to produce a 30% DNA inhibition (IC(30)) showed a >300,000- and a 14,000-fold range for the 24 and 96 hour treatments, respectively. In conclusion, data of the present study demonstrate (1) antiproliferative and apoptotic effects of taxol in human prostate tumors, (2) that neither effect was significantly enhanced by increasing the drug concentration above 1,200 nM, and (3) that the antiproliferative effect was affected more significantly by drug exposure time than the apoptotic effect.
Collapse
|