438 results on '"Shinji KURODA"'
Search Results
402. Osteogenic Potential of Mouse Periosteum-Derived Cells Sorted for CD90 In Vitro and In Vivo.
- Author
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YOU-KYOUNG KIM, HIDEMI NAKATA, MAIKO YAMAMOTO, MUNEMITSU MIYASAKA, SHOHEI KASUGAI, and SHINJI KURODA
- Published
- 2016
- Full Text
- View/download PDF
403. Excitonic Luminescence from Self-Organized Quantum Dots of CdTe Grown by Molecular Beam Epitaxy
- Author
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Shinji Kuroda, Shinji Kuroda, primary, Yoshikazu Terai, Yoshikazu Terai, additional, Kôki Takita, Kôki Takita, additional, Tsuyoshi Okuno, Tsuyoshi Okuno, additional, and Yasuaki Masumoto, Yasuaki Masumoto, additional
- Published
- 1999
- Full Text
- View/download PDF
404. Spin relaxation in CdTe/ZnTe quantum dots
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Yoshikazu Terai, Ye Chen, Tsuyoshi Okuno, Kôki Takita, Yasuaki Masumoto, and Shinji Kuroda
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Physics ,Photoluminescence ,Spin polarization ,Condensed matter physics ,Linear polarization ,Quantum dot ,ComputingMethodologies_DOCUMENTANDTEXTPROCESSING ,Hyperfine structure ,Excitation ,Circular polarization ,Magnetic field - Abstract
application/pdf, We have measured photoluminescence (PL) spectra and time-resolved PL in CdTe quantum dots (QDs) under the longitudinal magnetic field up to 10T. Circular polarization of PL increases with increasing magnetic field, while its linear polarization is absent under linearly polarized excitation. Time-resolved PL measurements clarified that this behavior is caused by the suppression of spin relaxation induced by the longitudinal magnetic field. We believe that this behavior is related to the hyperfine interaction of electron spin with magnetic momenta of lattice nuclei.
- Published
- 2005
405. Charactreristics of Stirling-type Pulse Tube Cryocooler
- Author
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Seiichi Koso, Hiroshi Yamamoto, Atushi Maruyama, Yasufumi Kasahara, Shinji Kuroda, Shirabe Akita, K. Yasohama, and Ataru Ichinose
- Published
- 2004
406. Effects ofTGF-β1andVEGF-Atransgenes on the osteogenic potential of bone marrow stromal cells in vitro and in vivo
- Author
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Dale R. Sumner, Amarjit S. Virdi, and Shinji Kuroda
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bone marrow ,Stromal cell ,Biomedical Engineering ,Medicine (miscellaneous) ,Biology ,Article ,VEGF-A ,Biomaterials ,03 medical and health sciences ,0302 clinical medicine ,Tissue engineering ,In vivo ,TGF-β1 ,medicine ,Bone regeneration ,Gene transfer ,030304 developmental biology ,0303 health sciences ,Transfection ,Cell biology ,RUNX2 ,medicine.anatomical_structure ,Cell culture ,tissue engineering ,030220 oncology & carcinogenesis ,Immunology ,Bone marrow - Abstract
An exogenous supply of growth factors and bioreplaceable scaffolds may help bone regeneration. The aim of this study was to examine the effects of TGF-β1 and VEGF-A transgenes on the osteogenic potential of bone marrow stromal cells. Rat bone marrow stromal cells were transfected with plasmids encoding mouse TGF-β1 and/or VEGF-A complementary DNAs and cultured for up to 28 days. Furthermore, collagen scaffolds carrying combinations of the plasmids-transfected cells were implanted subcutaneously in rats. The transgenes increased alkaline phosphatase activity, enhanced mineralized nodule formation, and elevated osteogenic gene expressions in vitro. In vivo, messenger RNA expression of osteogenic genes such as BMPs and Runx2 elevated higher by the transgenes. The data indicate that exogenous TGF-β1 and VEGF-A acted synergistically and could induce osteoblastic differentiation of bone marrow stromal cells in both cell culture and an animal model. The results may provide valuable information to optimize protocols for transgene-and-cell-based tissue engineering.
- Published
- 2012
407. Abstract 3505: EGFR-targeted hybrid plasmonic magnetic nanoparticles induce autophagy and apoptosis through DNA damage in non-small cell lung cancer cells
- Author
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Ailing W. Scott, Konstantin V Sokolov, Jack A. Roth, Rajagopal Ramesh, Manish Shanker, Arlene M. Correa, Justina O. Tam, Shinji Kuroda, and Tomohisa Yokoyama
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Cancer Research ,medicine.diagnostic_test ,biology ,Cell growth ,Cancer ,medicine.disease ,Molecular biology ,Flow cytometry ,Cell killing ,Oncology ,Apoptosis ,Monoclonal ,medicine ,biology.protein ,Cytotoxic T cell ,Antibody - Abstract
Nanoparticles represent a novel class of agents for cancer treatment. In the present study, we examined the effects of epidermal growth factor receptor (EGFR)-targeted hybrid plasmonic magnetic nanoparticles (NP) on non-small cell lung cancer (NSCLC) cells. The nanoparticles (NP) consisted of a paramagnetic iron core that is surrounded by a gold layer and is functionalized with monoclonal anti-EGFR antibody (C225) or control rabbit IgG antibody (IgG). The nanoparticles were tested against a panel of human lung cancer cells that were mutant (HCC827, H1819), wild-type (H1299) or null (H520) for EGFR and compared to EGFR-positive normal fibroblasts (MRC9, WI38) and normal human bronchial epithelial (NHBE) cells. Treatment of tumor cells with C225-NP resulted in a strong and significant inhibitory effect of cell growth compared to normal cells. C225-NP-mediated inhibitory effect was observed only in EGFR-positive tumor cells (HCC827, H1819, H1299) but not in EGFR-null H520 cells. EGFR-mutant cells (HCC827) were the most sensitive to C225-NP. No significant growth inhibitory effects were observed in IgG-NP-treated cells when compared to untreated cells. Molecular analysis showed C225-NP selectively inhibited phosphorylated p-EGFR protein expression and EGFR-mediated signal transduction resulting in induction of autophagy followed by apoptosis. Autophagy occurred as early as twenty-four hours after treatment with an increase in LC3-II content and autophagic vacuoles observed by Western blotting and electron microscopy respectively. Apoptosis as determined by flow cytometry and Western blotting showed an increase in the number of sub-G1 population cells and cleavage of caspase-3 and PARP in C225-NP-treated cells. Optical images determined by dark-field microscopy showed an increase in the concentration of C225-NP bound to EGFR-expressing NSCLC cells but not EGFR-null NSCLC cells. C225-NP exhibited 2-7 fold higher efficiency in induction of cell killing in comparison with the same amount of free C225 antibody. Free C225 antibody did not induce autophagy in cells. Investigation into how C225-NP but not C225 antibody or NP-alone triggers autophagy and initiates apoptosis showed induction of a DNA damage response as evidenced by the formation of γH2AX foci in C225-NP-treated cells. Minimal to no γH2AX foci were observed in cells that were untreated, treated with C225 antibody or NP-alone or treated with IgG-NP. Our data show that EGFR specific NP selectively induced cytotoxic effects in EGFR-expressing lung cancer cells via a novel cell-death mechanism that is not characteristic of the free antibody thus increasing efficacy of therapy. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 3505.
- Published
- 2010
408. Fluorescence XAFS analysis of local structures in iodine-doped Zn1-xCrxTe
- Author
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Shinji Kuroda, K. Ishikawa, Hironori Ofuchi, Yoshio Bando, K Zhang, and Masanori Mitome
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History ,Crystallography ,Absorption spectroscopy ,Ferromagnetism ,Chemistry ,Magnetism ,Transition temperature ,Curie temperature ,Crystal structure ,Magnetic semiconductor ,Computer Science Applications ,Education ,X-ray absorption fine structure - Abstract
Geometric structures for II-VI diluted magnetic semiconductor iodine-doped Zn1-xCrxTe films (x = 0.05) grown by molecular-beam epitaxy with high-temperature ferromagnetism were investigated by using fluorescence x-ray absorption fine structure (XAFS) measurement in order to elucidate the relationship between the geometric structure and the magnetic properties. The XAFS analysis has revealed that the local structures around Cr atoms are dependent on the growth temperature. For the samples grown at 360 and 390 °C, the majority of Cr atoms are tetrahedrally coordinated to Te atoms, indicating the formation of substitutional Cr on Zn-site in ZnTe lattice and/or zinc-blende (ZB) CrTe. On the contrary, for the samples grown at 300 and 330 °C the additional formation of secondary phases such as Cr-Te compounds was suggested. Therefore, it is deduced that the formation of secondary phase such as Cr-Te compounds are related to the increase of Curie temperature. The XAFS analysis has also revealed that the local structures do not depend on the I concentration. For the samples with different I concentrations, the Cr atoms form substitutional Cr on Zn-site in ZnTe lattice and/or ZB CrTe, corresponding to the result of TEM measurement.
- Published
- 2009
409. Reversible ferromagnetic spin ordering governed by hydrogen in Co-doped ZnO semiconductor
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Se-Young Jeong, Chul Hong Park, Chae-Ryong Cho, Sungkyun Park, Tae Eun Hong, Su Jae Kim, Seunghun Lee, Yong Chan Cho, Sung-Jin Kim, I.-K. Jeong, Shinji Kuroda, and Ho-Hyun Nahm
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Materials science ,Physics and Astronomy (miscellaneous) ,Hydrogen ,Condensed matter physics ,Magnetic circular dichroism ,Doping ,chemistry.chemical_element ,Magnetic semiconductor ,Electronic structure ,Condensed Matter::Materials Science ,Transition metal ,Ferromagnetism ,chemistry ,Condensed Matter::Strongly Correlated Electrons ,Spin (physics) - Abstract
We report a reversible manipulation of short-range spin ordering in Co-doped ZnO through hydrogenation and dehydrogenation processes. In both magnetic-circular dichroism and superconducting quantum interference device measurements, the ferromagnetism was clearly induced and removed by the injection and ejection of hydrogen, respectively. The x-ray photoelectron spectroscopy results and the first-principles electronic structure calculations consistently support the dependence of the ferromagnetism on the hydrogen position and the contribution of transition metal ions. The results suggest the ferromagnetic interaction between Co ions can be reversibly controlled by the hydrogen-mediated intrinsic spin ordering in Co doped ZnO.
- Published
- 2009
410. Quantum-mechanical analysis of far-infrared laser oscillation in p-type germamium
- Author
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Shinji Kuroda
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Physics ,Valence (chemistry) ,Condensed matter physics ,Oscillation ,Far-infrared laser ,Laser ,Magnetic field ,law.invention ,symbols.namesake ,Distribution function ,law ,symbols ,Hamiltonian (quantum mechanics) ,Quantum - Abstract
Recent theoretical and experimental achievements on far-infrared (FIR) laser oscillation in p-Ge are reported. The experimentally observed cyclotron-resonance and inter-valence band laser oscillations are explained by theories. The Luttinger Hamiltonian describing the valence bands in the presence of crossed electric and magnetic fields are solved and the distribution functions of holes are derived to evaluate (negative) absorption coefficients in the FIR-range. Experimental results studying the influence of uniaxial stress on the oscillations are also presented and compared with the theory.
- Published
- 1991
411. Fluorescence virus-guided capturing system of human colorectal circulating tumour cells for non-invasive companion diagnostics.
- Author
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Kunitoshi Shigeyasu, Hiroshi Tazawa, Yuuri Hashimoto, Yoshiko Mori, Masahiko Nishizaki, Hiroyuki Kishimoto, Takeshi Nagasaka, Shinji Kuroda, Yasuo Urata, Goel, Ajay, Shunsuke Kagawa, and Toshiyoshi Fujiwara
- Subjects
COLON cancer treatment ,CANCER invasiveness ,COLON cancer diagnosis ,GREEN fluorescent protein ,CANCER cells ,TARGETED drug delivery ,FLUORESCENCE ,PROTEIN expression - Abstract
Background Molecular-based companion diagnostic tests are being used with increasing frequency to predict their clinical response to various drugs, particularly for molecularly targeted drugs. However, invasive procedures are typically required to obtain tissues for this analysis. Circulating tumour cells (CTCs) are novel biomarkers that can be used for the prediction of disease progression and are also important surrogate sources of cancer cells. Because current CTC detection strategies mainly depend on epithelial cell-surface markers, the presence of heterogeneous populations of CTCs with epithelial and/or mesenchymal characteristics may pose obstacles to the detection of CTCs. Methods We developed a new approach to capture live CTCs among millions of peripheral blood leukocytes using a green fluorescent protein (GFP)-expressing attenuated adenovirus, in which the telomerase promoter regulates viral replication (OBP-401, TelomeScan). Results Our biological capturing system can image epithelial and mesenchymal tumour cells with telomerase activities as GFP-positive cells. After sorting, direct sequencing or mutation-specific PCR can precisely detect different mutations in KRAS, BRAF and KIT genes in epithelial, mesenchymal or epithelial-mesenchymal transition-induced CTCs, and in clinical blood samples from patients with colorectal cancer. Conclusions This fluorescence virus-guided viable CTC capturing method provides a non-invasive alternative to tissue biopsy or surgical resection of primary tumours for companion diagnostics. [ABSTRACT FROM AUTHOR]
- Published
- 2015
- Full Text
- View/download PDF
412. Formation of Silazirconacyclopentene via Zirconium−Silene Complex and Alkyne
- Author
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Fumiko Dekura, Miwako Mori, and Shinji Kuroda
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chemistry.chemical_classification ,Silene ,Zirconium ,Colloid and Surface Chemistry ,biology ,chemistry ,Polymer chemistry ,Alkyne ,chemistry.chemical_element ,General Chemistry ,biology.organism_classification ,Biochemistry ,Catalysis - Published
- 1999
413. P1-154: Antitumor effect of Telomerase-Selective Oncolytic Adenoviral Agent OBP-301 (Telomelysin) in pleural dissemination of human malignant mesothelioma
- Author
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Yasuo Urata, Toru Kojima, Yuichi Watanabe, Shunsuke Kagawa, Futoshi Uno, Shinji Kuroda, Noriaki Tanaka, Toshiyoshi Fujiwara, and Yuuri Hashimoto
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Pulmonary and Respiratory Medicine ,Telomerase ,Oncology ,business.industry ,medicine ,Cancer research ,Mesothelioma ,medicine.disease ,Telomelysin ,business ,Oncolytic virus - Published
- 2007
414. P3-028: Mutual sensitization with telomerase-specific oncolytic virotherapy and ionizing radiation in cytotoxic activity against human cancer
- Author
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Toshiya Fujiwara, Yasuo Urata, Toru Kojima, Toshiyoshi Fujiwara, Shunsuke Kagawa, Futoshi Uno, Noriaki Tanaka, and Shinji Kuroda
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Pulmonary and Respiratory Medicine ,Telomerase ,medicine.anatomical_structure ,Oncology ,business.industry ,Cancer research ,Medicine ,Cytotoxic T cell ,business ,Human cancer ,Sensitization ,Oncolytic virus ,Ionizing radiation - Published
- 2007
415. Characterization of room temperature ferromagnetic Mn–Si compound synthesized on SiC substrate
- Author
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Fumiyoshi Takano, Kôki Takita, Shinji Kuroda, Hironori Ofuchi, and Hiro Akinaga
- Subjects
Paramagnetism ,Crystallography ,Materials science ,Nuclear magnetic resonance ,Ferromagnetism ,Annealing (metallurgy) ,Magnetic circular dichroism ,General Physics and Astronomy ,Curie temperature ,Wafer ,Epitaxy ,Spectral line - Abstract
Manganese silicide (Mn–Si) related compound with a Curie temperature (TC) of 300K was synthesized on a 4H-SiC homoepitaxial wafer. Thin Mn layer was deposited on the SiC wafer, and then annealing was performed to diffuse the Mn atoms into the SiC epitaxial layer. Transmission magnetic circular dichroism spectra reflected that of the SiC wafer, although the structural investigations suggested that the dominant phase of the synthesized layer was paramagnetic Mn5Si2. At this stage, two possible explanations are considered the origin of the observed ferromagnetism. One is that a small amount of carbon (C) incorporated into the Mn5Si2 host induced the ferromagnetic order in Mn5Si2. On the other hand, the partial formation of a ferromagnetic SiC-related component at the vicinity of the lower side of the interface between SiC and Mn5Si2 layers is considered the other possible explanation.
- Published
- 2006
416. Suppression of ferromagnetism due to hole doping in Zn1−xCrxTe grown by molecular-beam epitaxy
- Author
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Nobuhiko Ozaki, Kôki Takita, Shinji Kuroda, T. Kumekawa, S. Marcet, I. Okabayashi, and Nozomi Nishizawa
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Condensed Matter::Materials Science ,Magnetization ,Hysteresis ,Materials science ,Physics and Astronomy (miscellaneous) ,Condensed matter physics ,Ferromagnetism ,Electrical resistivity and conductivity ,Condensed Matter::Strongly Correlated Electrons ,Magnetic semiconductor ,Magnetic hysteresis ,Arrott plot ,Molecular beam epitaxy - Abstract
Electric and magnetic properties were investigated on p-type Zn1−xCrxTe doped with nitrogen (N) as an acceptor. Thin films of p-Zn1−xCrxTe(x≦0.09) were grown by molecular-beam epitaxy with the supply of N2 gas excited by rf plasma. With the increase of Cr composition x at an almost fixed N concentration of the order of 1020cm−3, the temperature dependence of resistivity changed from metallic behavior to an insulating one, accompanied with a significant decrease of the hole concentration. The magnetization measurements revealed that ferromagnetic behaviors observed in undoped Zn1−xCrxTe were suppressed due to the nitrogen doping; with N concentrations of the order of 1020cm−3, hysteresis loops in the magnetization curve disappeared, the magnitude of magnetization decreased, and the ferromagnetic transition were not observed down to 2 K according to the Arrott plot analysis. These experimental findings are discussed on the basis of the ferromagnetic double exchange interaction which is considered to work on...
- Published
- 2005
417. Negative component observed in the angular dependence of magnetoresistance in the single crystal of Pr x Y1−x Ba2Cu3O7−δ
- Author
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Shinji Kuroda, Hiroyuki Hoshi, Kôki Takita, Hidehiro Nakata, and Shigeki Yamada
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Weak localization ,Physics ,Condensed matter physics ,Magnetoresistance ,Component (thermodynamics) ,Dephasing ,General Physics and Astronomy ,Inelastic scattering ,Thermal conduction ,Single crystal ,Magnetic field - Abstract
Detailed measurements of magnetoresistance(MR), the angular dependence as well as the magnetic field dependence, of PrxY1−xBa2Cu3O7−δ single crystals have been performed aboveTc forx up to 0.5. In the samples withx around 0.4, it is found that a negative component is observed as a clear dip in the angular dependence of MR, which is hidden by a large positive component in the measurement of the magnetic field dependence. According to the analysis based on a model wher the negative component is due to the Anderson weak localization, the temperature dependence of the dephasing lengthLc is obtained asLc(T) ∝T−1, which is expected for the inelastic scattering between 2D-electrons. The result indicates that the random potential induced by Pr strongly affects the conduction in CuO2 layer.
- Published
- 1996
418. Bone regeneration of calvarial defect using marine calcareous-derived beta-tricalcium phosphate macrospheres.
- Author
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Chou, Joshua, Jia Hao, Shinji Kuroda, Ben-Nissan, Besim, Milthopre, Bruce, and Makoto Otsuka
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BONE regeneration ,BONE remodeling ,HYPEROSTOSIS frontalis interna ,CALCIUM phosphate ,ANIMAL exoskeletons - Abstract
The aim of this study was to examine the bone regeneration properties of beta-tricalcium phosphate hydrothermally converted from foraminifera carbonate exoskeleton in the repair of rat calvarial defect. These natural materials possess unique interconnected porous network with uniform pore size distribution, which can be potentially advantageous. In total, 20 adult male Wistar rats received full-thickness calvarial defect with a diameter of 5 mm. The rate of newly formed bone was measured radiologically by X-ray and micro-computed tomography and by histologic examination. After 2 weeks, the beta-tricalcium phosphate group exhibited full closure of the defect site, while control group remained unrestored at the end of the 6-week experimentation. It was observed that the newly regenerated bone thickened over the course of the experiment in the beta-tricalcium phosphate group. No soft tissue reaction was observed around the beta-tricalcium phosphate implant and the rats remained healthy. These results showed that repair of the calvarial defect can be achieved by biomimetic beta-tricalcium phosphate macrospheres, which hold potential for application as bone grafts for bone augmentation surgeries. [ABSTRACT FROM AUTHOR]
- Published
- 2014
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419. Bone Regeneration of Rat Tibial Defect by Zinc-Tricalcium Phosphate (Zn-TCP) Synthesized from Porous Foraminifera Carbonate Macrospheres.
- Author
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Joshua Chou, Jia Hao, Shinji Kuroda, Bishop, David, Ben-Nissan, Besim, Milthorpe, Bruce, and Makoto Otsuka
- Abstract
Foraminifera carbonate exoskeleton was hydrothermally converted to biocompatible and biodegradable zinc-tricalcium phosphate (Zn-TCP) as an alternative biomimetic material for bone fracture repair. Zn-TCP samples implanted in a rat tibial defect model for eight weeks were compared with unfilled defect and beta-tricalcium phosphate showing accelerated bone regeneration compared with the control groups, with statistically significant bone mineral density and bone mineral content growth. CT images of the defect showed restoration of cancellous bone in Zn-TCP and only minimal growth in control group. Histological slices reveal bone in-growth within the pores and porous chamber of the material detailing good bone-material integration with the presence of blood vessels. These results exhibit the future potential of biomimetic Zn-TCP as bone grafts for bone fracture repair. [ABSTRACT FROM AUTHOR]
- Published
- 2013
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420. The valence of Pr IN PrBa2Cu3O7−δ and the related compounds as determined by neutron powder diffraction
- Author
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Shinji Kuroda, Hajime Asano, Kôki Takita, Takeshi Ohshima, and H. Baba
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Neutron powder diffraction ,Crystallography ,Valence (chemistry) ,Nuclear magnetic resonance ,Materials science ,chemistry ,chemistry.chemical_element ,Crystal structure ,Electrical and Electronic Engineering ,Condensed Matter Physics ,Oxygen ,Electronic, Optical and Magnetic Materials - Abstract
We performed the crystal structure analysis of PrxNd1−x(Ba1.9Nd0.1)Cu3O7−δ system from x = 0 to 1.0 by neutron powder diffraction. We are especially interested in the distances of M(2)–O(4) and M(2)–O(5) in order to reveal the effect of substitution of Nd by Pr, where M(2) indicates the site occupied by Nd/Pr and O(4) and O(5) are the oxygen sites in the CuO2 layer. As a result, both distances become anomalously smaller with increase of the Pr-contents. According to an estimation by the Bond-Valence-Sum of M(2), the valence of Pr ranges from +3.4 to +3.5.
- Published
- 1994
421. New immobilized osteopenia model in mice
- Author
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Shinji Kuroda, Shohei Kasugai, Hisatomo Kondo, Yoshihiro Waki, Keiichi Ohya, and Ken-ichi Miyamoto
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Pharmacology ,Osteopenia ,medicine.medical_specialty ,Endocrinology ,Chemistry ,Internal medicine ,medicine ,medicine.disease - Published
- 2000
422. Abrupt reduction in poly-Si etch rate in HBr/O[sub 2] plasma
- Author
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Shinji Kuroda and Hiroaki Iwakuro
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fungi ,Hydrogen bromide ,technology, industry, and agriculture ,General Engineering ,Analytical chemistry ,chemistry.chemical_element ,macromolecular substances ,Oxygen ,Ion ,chemistry.chemical_compound ,stomatognathic system ,chemistry ,Etch pit density ,X-ray photoelectron spectroscopy ,Etching (microfabrication) ,Surface layer ,Reactive-ion etching - Abstract
The effect of oxygen on polycrystalline-Si (poly-Si) and SiO2 etching in hydrogen bromide (HBr) reactive ion etching plasmas has been studied by measuring etch rates and using x-ray photoelectron spectroscopy (XPS) to study compositional changes in the surface layer. The etch rate of the poly-Si increases dramatically from 30 to 235 nm/min as the O2 concentration increases from 0% to 25%, whereas the SiO2 etch rate gradually decreases from 3 to 1 nm/min. Above 30% O2 in HBr, the poly-Si etch rate abruptly decreases by a factor of 16 compared with that at 25%. From XPS analysis, it is found that the abrupt decrease of the poly-Si etch rate at O2 concentrations of more than 30% is closely related with the composition and thickness of an SiBrxOy layer formed during the HBr/O2 plasma exposure. The SiBrxOy layer has a composition of nearly SiO2. Br ions cannot permeate the SiBrxOy layer formed in plasmas containing 30% O2 in HBr (or greater), and therefore, the poly-Si etch terminates.
- Published
- 1998
423. Activities of the basal ganglia neurons during mastication in the awake rabbit
- Author
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Yuji Masuda, Takakazu Yagi, Osamu Hidaka, Shinji Kuroda, Akira Komuro, Toshifumi Morimoto, and Hirofumi Tsuji
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General Neuroscience ,Basal ganglia ,Rabbit (nuclear engineering) ,General Medicine ,Anatomy ,Biology ,Mastication - Published
- 1998
424. Effects of TGF-β1 and VEGF-A transgenes on the osteogenic potential of bone marrow stromal cells in vitro and in vivo.
- Author
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Shinji Kuroda, Sumner, Dale R., and Virdi, Amarjit S.
- Subjects
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TRANSFORMING growth factors , *VASCULAR endothelial growth factors , *TRANSGENES , *MESENCHYMAL stem cells , *TISSUE engineering - Abstract
An exogenous supply of growth factors and bioreplaceable scaffolds may help bone regeneration. The aim of this study was to examine the effects of TGF-β1 and VEGF-A transgenes on the osteogenic potential of bone marrow stromal cells. Rat bone marrow stromal cells were transfected with plasmids encoding mouse TGF-β1 and/or VEGF-A complementary DNAs and cultured for up to 28 days. Furthermore, collagen scaffolds carrying combinations of the plasmids-transfected cells were implanted subcutaneously in rats. The transgenes increased alkaline phosphatase activity, enhanced mineralized nodule formation, and elevated osteogenic gene expressions in vitro. In vivo, messenger RNA expression of osteogenic genes such as BMPs and Runx2 elevated higher by the transgenes. The data indicate that exogenous TGF-β1 and VEGF-A acted synergistically and could induce osteoblastic differentiation of bone marrow stromal cells in both cell culture and an animal model. The results may provide valuable information to optimize protocols for transgene-and-cell-based tissue engineering. [ABSTRACT FROM AUTHOR]
- Published
- 2012
- Full Text
- View/download PDF
425. Bone Increase in Rat Tibiae by Local Administration of Amino-Terminally Truncated rhFGF-4(73-206).
- Author
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Shinji Kuroda, Hisatomo Kondo, Keiichi Ohya, and Shohei Kasugai
- Subjects
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EMBRYOLOGY , *AMINO acids , *CELLS , *BONES - Abstract
Fibroblast growth factor 4 (FGF-4) plays important roles in bone development during embryogenesis. Human FGF-4 consists of 206 amino acid residues. We produced amino-terminally truncated rhFGF-4, named rhFGF-4(73-206), that increases bone mineral density when systemically administered to mice. In the present study, we examined the effects of rhFGF-4(73-206) in bone after local administration. We injected 1 μg of rhFGF-4(73-206) into tibiae of 10-week-old Sprague-Dawley rats. At days 4 and 7, sets of animals were subjected for tibial bone marrow cell culture in an osteogenic medium. The bone marrow cells from FGF-4-injected tibiae produced more alkaline phosphatase-positive cells and mineralized nodules than those from control tibiae, indicating that local injection of rhFGF-4(73-206) increased the osteoblastic population in the bone marrow. The remaining sets of animals were killed on days 7 and 10. The tibiae were then analyzed with soft X-ray, dual energy X-ray absorptiometry, peripheral quantitative computed tomography, and histomorphometry. The radiographic analyses revealed increases in trabecular bone in the tibiae but no difference in the cortical bone between the rhFGF-4(73-206) group and the control group. High bone turnover and a derived increase of trabecular bone mineral density were demonstrated by histomorphometry in the rhFGF-4(73-206) group. The present results indicate that local injection with rhFGF-4(73-206) elicited an increase in the osteogenic cell population in the tibial bone marrow, which resulted in more trabecular bone. [ABSTRACT FROM AUTHOR]
- Published
- 2007
- Full Text
- View/download PDF
426. A new fabrication technology for AlGaAs/GaAs HEMT LSIs using InGaAs nonalloyed ohmic contacts
- Author
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T. Katakami, Masayuki Abe, Takashi Mimura, Naoki Harada, and Shinji Kuroda
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Materials science ,Equivalent series resistance ,business.industry ,Transistor ,High-electron-mobility transistor ,Ring oscillator ,Electronic, Optical and Magnetic Materials ,law.invention ,Gallium arsenide ,chemistry.chemical_compound ,chemistry ,law ,Optoelectronics ,Static random-access memory ,Electrical and Electronic Engineering ,Resistor ,business ,Ohmic contact - Abstract
The authors studied the nonalloyed ohmic characteristics of HEMTs (high electron mobility transistors). At high integration levels, nonalloyed ohmic contacts were found to have two advantages: an extremely short ohmic length with low parasitic source series resistance and direct connection between the source/drain and gate with the same metal. The propagation delay in a ring oscillator with a single-metal source/drain and gate formed simultaneously was 37 ps/gate (L/sub g/=0.9 mu m). The very short ohmic metal contacts and just three contact holes made it possible to reduce the memory cell area greatly. The cell is 21.5*21.5 mu m/sup 2/, one of the smallest ever reported for a GaAs-based static RAM. Using smaller load HEMTs or resistor loads in the memory cell, combined with nonalloyed ohmic technology with quarter- or subquarter-micrometer-gate HEMTs it is possible to fabricate a very-high-speed LSI such as a 64-kb static RAM with a reasonable chip size. >
- Published
- 1989
427. Polarization of the far‐infrared laser oscillation inp‐Ge in Faraday configuration
- Author
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Susumu Komiyama, Toyoji Yamamoto, and Shinji Kuroda
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Physics ,Optical isolator ,Linear polarization ,business.industry ,Far-infrared laser ,Physics::Optics ,General Physics and Astronomy ,Optical polarization ,Polarization (waves) ,law.invention ,symbols.namesake ,Optics ,law ,Faraday effect ,symbols ,Atomic physics ,Faraday cage ,business ,Faraday rotator - Abstract
Polarization of far‐infrared laser oscillation in p‐Ge under crossed electric and magnetic fields is studied by use of a linear polarizer. The laser emission is found to be polarized with the primary axis nearly parallel to the current vector in the Ge laser rod, independent of the strength of electric and magnetic fields and the oscillation wavelength. An analysis of the resonance condition of an optical resonant cavity placed in Faraday configuration together with the experimental results make it probable that net Faraday rotation vanishes in the laser oscillation. To support this it is pointed out that both the free‐carrier Faraday effect and the intervalence band Faraday effect are strongly affected by the strong radiations caused by laser oscillation. The relation of the anisotropy of carrier distribution in velocity space to the observed polarization is also discussed.
- Published
- 1987
428. HEMT with nonalloyed ohmic contacts using n+-InGaAs cap layer
- Author
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Takashi Mimura, Shinji Kuroda, T. Katakami, and Naoki Harada
- Subjects
Materials science ,business.industry ,Contact resistance ,Electrical engineering ,Heterojunction ,High-electron-mobility transistor ,Electronic, Optical and Magnetic Materials ,Gallium arsenide ,chemistry.chemical_compound ,chemistry ,Optoelectronics ,Field-effect transistor ,Electrical and Electronic Engineering ,business ,Layer (electronics) ,Ohmic contact ,Quantum tunnelling - Abstract
We have investigated nonalloyed ohmic contacts on HEMT's using a highly conductive n+-InGaAs layer. The minimum specific contact resistance obtained was 4.8 × 10-7Ω.cm2, and the IV characteristics were equal to or better than those of conventional HEMT's with alloyed ohmic contacts. The maximum transconductances of a nonalloyed ohmic HEMT were 240 mS/mm at 300K and 340 mS/mm at 88K for a gate length of 1.1 µm. We conclude that it is not necessary for HEMT's with two-dimensional electron gas (2DEG) channels to have alloyed ohmic contacts, because the tunneling conduction is significant at the n-GaAs/n-AlGaAs/undoped GaAs double heterojunction.
- Published
- 1987
429. Current-gain cutoff frequency comparison of InGaAs HEMTs
- Author
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S. Sasa, Shinji Kuroda, Naoki Harada, and K. Hikosaka
- Subjects
Materials science ,business.industry ,Transistor ,Gate length ,High-electron-mobility transistor ,Cutoff frequency ,Electronic, Optical and Magnetic Materials ,law.invention ,Gallium arsenide ,chemistry.chemical_compound ,chemistry ,law ,Optoelectronics ,Field-effect transistor ,Electrical and Electronic Engineering ,business - Abstract
The current-gain cutoff frequency performance of pseudomorphic InGaAs/AlGaAs (20% InAs composition) high-electron-mobility transistors (HEMTs) on GaAs is compared to that of lattice-matched InGaAs/InAlAs HEMTs on InP. The current-gain cutoff frequency (f/sub t/) characteristics as a function of gate length (L/sub g/) indicate that the f/sub t/-L/sub g/ product of approximately 26 GHz- mu m in InGaAs/InAlAs HEMTs is 23% higher than that of approximately 21 GHz- mu m in InGaAs/AlGaAs HEMTs. The performance of InGaAs/AlGaAs HEMTs is also 46% higher than that of conventional GaAs/AlGaAs HEMTs ( approximately 18 GHz- mu m). These data are very useful in improving the device performance of HEMTs for a given gate length. >
- Published
- 1988
430. Magneto-Optical Recording of Sputtered Garnet Films Crystallized during Deposition
- Author
-
H. Kano, Keiji Shono, Shinji Kuroda, Ogawa Seiya, and Nagaaki Koshino
- Subjects
Materials science ,business.industry ,Coercivity ,Laser ,Amorphous solid ,law.invention ,Hysteresis ,Transition metal ,Sputtering ,law ,Optoelectronics ,Figure of merit ,business ,Deposition (law) - Abstract
In-situ crystallized Bi,Ga:DyIG films were deposited on GGG substrates by sputtering. The films had quite smooth surfaces and showed square hysteresis loops with high coercivity. Dynamic recording was carried out using an Ar laser. The figure of merit of the disk with an Al reflector was about 10 times larger than that of amorphous rare-earth transition metal magneto-optic films. A CNR as high as 54 dB was obtained for a bit length of 1.4 μm.
- Published
- 1989
431. Control of excitonic motion in modulation-doped (Cd,Mn)Te QW by magnetic and electric fields
- Author
-
Kôki Takita, Takashi Tokizaki, Hiro Akinaga, Fumiyoshi Takano, and Shinji Kuroda
- Subjects
Condensed Matter::Quantum Gases ,Condensed matter physics ,Condensed Matter::Other ,Chemistry ,Exciton ,Doping ,Condensed Matter::Mesoscopic Systems and Quantum Hall Effect ,Magnetic field ,Condensed Matter::Materials Science ,Modulation ,Electric field ,Semiconductor quantum wells ,Tellurium compounds ,Quantum well - Abstract
We successfully observed the time development of an electric‐field‐induced drift of a negatively‐charged exciton X− formed in an n‐type modulation‐doped (Cd,Mn)Te quantum well. The drift of X− was found to be promoted by magnetic fields. This could be resulting from the suppression of an exciton‐magnetic‐polaron formation.
432. Correlation between Cr distribution and ferromagnetism in iodine-doped (Zn,Cr)Te
- Author
-
Kôki Takita, Yoshio Bando, Masanori Mitome, Nozomi Nishizawa, K. Ishikawa, Shinji Kuroda, and Tomasz Dietl
- Subjects
Materials science ,Ferromagnetism ,Condensed matter physics ,Distribution (number theory) ,Spinodal decomposition ,General Physics and Astronomy ,Iodine doped ,Molecular beam epitaxy
433. Cross-sectional STM Study of Impurity States in Diluted Magnetic Semiconductor (Zn,Cr)Te.
- Author
-
Ken Kanazawa, Shoji Yoshida, Hidemi Shigekawa, and Shinji Kuroda
- Subjects
SCANNING tunneling microscopy ,DILUTED magnetic semiconductors ,MULTILAYERS ,CHEMICAL structure ,BAND gaps ,ZINC telluride ,METAL inclusions - Abstract
We performed cross-sectional scanning tunneling microscopy I spectroscopy (STM/STS) measurement on multi-layered structure (Zn
0.97 ,Cr0.03 )Te I buffer undoped ZnTe I substrate p-ZnTe. The result of STS measurements on (Zn,Cr)Te clearly showed the existence of Cr impurity states at a deep position within the band-gap of the host ZnTe. [ABSTRACT FROM AUTHOR]- Published
- 2013
- Full Text
- View/download PDF
434. Far-Infrared Laser Oscillation in p-Ge Using External Reflectors
- Author
-
Susumu Komiyama and Shinji Kuroda
- Subjects
Physics ,business.industry ,Oscillation ,Far-infrared laser ,General Engineering ,Physics::Optics ,General Physics and Astronomy ,Laser oscillation ,Radiation ,Directivity ,Resonator ,Optics ,Interference (communication) ,Optoelectronics ,business ,Line (formation) - Abstract
Intervalence band laser oscillation in p-Ge is achieved in a semiconfocal resonator system using external reflectors and the directivity of the output radiation is thereby largely improved. The spectrum of the radiation consists of several discrete lines due to simultaneous oscillations in multimodes. Preliminary attempts to select a single oscillation line by means of Fabri-Perot type interference are also described.
- Published
- 1987
435. SMAD4 Germline Pathogenic Variant-Related Gastric Juvenile Polyposis with Adenocarcinoma Treated with Laparoscopic Total Gastrectomy: A Case Report.
- Author
-
Yuya Sakurai, Satoru Kikuchi, Kunitoshi Shigeyasu, Yoshihiko Kakiuchi, Takehiro Tanaka, Hibiki Umeda, Masaki Sakamoto, Sho Takeda, Shuya Yano, Mashu Futagawa, Fumino Kato, Reimi Sogawa, Hideki Yamamoto, Shinji Kuroda, Yoshitaka Kondo, Fuminori Teraishi, Hiroyuki Kishimoto, Masahiko Nishizaki, Shunsuke Kagawa, and Akira Hirasawa
- Subjects
- *
CAPSULE endoscopy , *GASTRECTOMY , *DIAGNOSIS , *GENETIC disorders , *LYMPHADENECTOMY , *MORBID obesity - Abstract
Background: Juvenile polyposis syndrome is an uncommon, autosomal-dominant hereditary disease that is distinguished by multiple polyps in the stomach or intestinal tract. It is associated with a high risk of malignancy. Pathogenic variants in SMAD4 or BMPR1A account for 40% of all cases. Case Report: A 49-year-old woman underwent esophagogastroduodenoscopy because of exacerbation of anemia. She had numerous erythematous polyps in most parts of her stomach. Based on biopsy findings, juvenile polyposis syndrome (JPS) was suspected morphologically, but there was no evidence of malignancy. Colonoscopy showed stemmed hyperplastic polyps and an adenoma; video capsule endoscopy revealed no lesions in the small intestine. After preoperative surveillance, laparoscopic total gastrectomy with D1 lymph node dissection was performed to prevent malignant transformation. The pathological diagnosis was juvenile polyp-like polyposis with adenocarcinoma. In addition, a germline pathogenic variant in the SMAD4 gene was detected with genetic testing. Conclusions: JPS can be diagnosed with endoscopy and genetic testing. Further, appropriate surgical management may prevent cancer-related death in patients with this condition. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
436. Optical control of the spin of a magnetic atom in a semiconductor : hybrid hole-Manganese spin and Chromium spin
- Author
-
Lafuente-Sampietro, Alban, Institut Néel (NEEL), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Université Grenoble Alpes, Université de Tsukuba, Lucien Besombes, Shinji Kuroda, and STAR, ABES
- Subjects
Semi-Conductors ,Quantum dots ,Boîtes quantiques ,[PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci] ,Spins ,Semi-Conducteurs ,[PHYS.COND.CM-MS] Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci] - Abstract
Two different single spin systems are studied in this thesis: single Mn spin in positively charged quantum dots, and single Cr atom in a neutral quantum dots. Both are probed optically, using the photoluminescence of a single dot. Both systems are strongly coupled to phonons and strains. This coupling opens new ways to probe and control the spins of the magnetic atoms, not only optically, but also by modulating the strain state at their position.Using resonant photoluminescence, we demonstrate the existence of optical Λ-level systems in Mn-doped positively charged quantum dots, and use them to study the dynamics of the hole-Mn hybrid spin. It reveals hole-Mn spin flip-flops in the nanosecond range due to the interplay of the interaction with acoustic phonons and the hole-Mn exchange interaction. We also show that degenerated electron-Mn states separated by spin flips of two units are coupled through the in-plane strain anisotropy, and study this strain induced coherent dynamics.Using magneto-optic experiments, we are able to probe the spin of a single Cr atom and extract a magnetic anisotropy D0 in the meV range. Several parameters of the QD are extracted from these experiments, and, especially, we show that the h-Cr coupling is anti-ferromagnetic. We demonstrate that the Cr spin can be prepared using resonant optical pumping. These experiments evidence a Cr relaxation time under excitation in the 10 nanoseconds range. This relaxation is driven by hole-Cr spin flip-flops caused by the interplay of the interaction with acoustic phonons and the hole-Cr exchange interaction. A relaxation in the dark in the microseconds range was also measured. Possibility of control of the Cr spin was also demonstrated using the optical Stark effect., Deux systèmes de spins uniques sont étudiés dans cette thèse : d’abord un unique atome de Mn dans une boîte quantique chargée positivement, puis un unique atome de Cr dans une boîte quantique neutre. Cette étude a été entièrement réalisée par des moyens optiques, via la photoluminescence d’une boîte unique. Ces deux systèmes sont fortement couplés aux phonons et aux contraintes. Ce couplage permet de ne plus se limiter à une détection et une manipulation du spin optique, mais ouvre également la possibilité de le faire en modulant le champ de contrainte.Par des expériences de photoluminescence résonante, nous montrons l’existence de niveaux optique en Λ dans les boîtes quantiques chargées positivement et dopées d’un unique atome de Mn. Ces niveaux en Λ sont utilisés pour étudier la dynamique du spin hybride trou-Mn. Cette étude révèle l’existence de flip-flops des spins du trou et du Mn à l’échelle de la nanoseconde, dus à l’interaction d’échange trou-Mn et à l’interaction avec les phonons acoustiques. Un couplage par l’anisotropie des contraintes dans le plan de niveaux électron-Mn dégénérés et séparé par un spin flip de deux unités est aussi démontré, et dynamique cohérente induite par les contraintes est étudiée en détail.Grâce à des expériences magnéto-optiques, nous avons pu détecter la photoluminescence d’un atome de Cr unique dans une boîte quantique, et extraire une anisotropie magnétique du spin du Cr de quelques meV. De nombreux paramètres des boîtes étudiées peuvent être extrait de ces expériences, et nous montrons notamment que le couplage trou-Cr est antiferromagnétique. Nous démontrons que le spin du Cr peut être préparé par pompage optique résonant. Ces expériences ont permis de montrer que, sous excitation, le spin du Cr fait des flip-flops avec celui du trou, causé par l’interaction d’échange trou-Cr et le couplage aux phonons acoustiques. Ces flip-flops causent une relaxation rapide du spin du Cr sous excitation, mesurée comme de l’ordre de quelques dizaines de nanosecondes. Dans le noir, nous avons trouvé que le spin du Cr relaxe en quelques microsecondes. Finalement, nous avons aussi démontré la possibilité de contrôler le spin du Cr par l’effet Stark optique.
- Published
- 2018
437. Observation of the inverse spin Hall effect in the topological crystalline insulator SnTe using spin pumping.
- Author
-
Shinobu Ohya, Akiyori Yamamoto, Tomonari Yamaguchi, Ryo Ishikawa, Ryota Akiyama, Le Duc Anh, Goel, Shobhit, Wakabayashi, Yuki K., Shinji Kuroda, and Masaaki Tanaka
- Subjects
- *
SPIN Hall effect , *TOPOLOGY , *SPINTRONICS - Abstract
Topological crystalline insulator SnTe is a promising material for future spintronics applications because of the strong spin-orbit coupling and surface states protected by the mirror symmetry of the crystal. In this paper, using a high-quality epitaxial (001)-oriented Fe/SnTe/CdTe/ZnTe heterostructure grown on GaAs, we successfully observe the inverse spin Hall effect in SnTe induced by spin pumping, which is confirmed by detailed analyses of the dependence of the electromotive force on the microwave power, magnetic-field angle, and temperature. By a rough estimation, a relatively large spin Hall angle of ~0.01 is obtained for bulk SnTe at room temperature. This large value may be partially caused by the surface states. Our result suggests that SnTe can be used for efficient spin-charge current conversion. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
438. Optical control of the spin of a magnetic atom in a semiconductor: hybrid hole-Manganese spin and Chromium spin
- Author
-
Alban Lafuente-Sampietro, Institut Néel (NEEL), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Université Grenoble Alpes, Université de Tsukuba, Lucien Besombes, and Shinji Kuroda
- Subjects
Semi-Conductors ,Quantum dots ,Boîtes quantiques ,[PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci] ,Spins ,Semi-Conducteurs - Abstract
Two different single spin systems are studied in this thesis: single Mn spin in positively charged quantum dots, and single Cr atom in a neutral quantum dots. Both are probed optically, using the photoluminescence of a single dot. Both systems are strongly coupled to phonons and strains. This coupling opens new ways to probe and control the spins of the magnetic atoms, not only optically, but also by modulating the strain state at their position.Using resonant photoluminescence, we demonstrate the existence of optical Λ-level systems in Mn-doped positively charged quantum dots, and use them to study the dynamics of the hole-Mn hybrid spin. It reveals hole-Mn spin flip-flops in the nanosecond range due to the interplay of the interaction with acoustic phonons and the hole-Mn exchange interaction. We also show that degenerated electron-Mn states separated by spin flips of two units are coupled through the in-plane strain anisotropy, and study this strain induced coherent dynamics.Using magneto-optic experiments, we are able to probe the spin of a single Cr atom and extract a magnetic anisotropy D0 in the meV range. Several parameters of the QD are extracted from these experiments, and, especially, we show that the h-Cr coupling is anti-ferromagnetic. We demonstrate that the Cr spin can be prepared using resonant optical pumping. These experiments evidence a Cr relaxation time under excitation in the 10 nanoseconds range. This relaxation is driven by hole-Cr spin flip-flops caused by the interplay of the interaction with acoustic phonons and the hole-Cr exchange interaction. A relaxation in the dark in the microseconds range was also measured. Possibility of control of the Cr spin was also demonstrated using the optical Stark effect.; Deux systèmes de spins uniques sont étudiés dans cette thèse : d’abord un unique atome de Mn dans une boîte quantique chargée positivement, puis un unique atome de Cr dans une boîte quantique neutre. Cette étude a été entièrement réalisée par des moyens optiques, via la photoluminescence d’une boîte unique. Ces deux systèmes sont fortement couplés aux phonons et aux contraintes. Ce couplage permet de ne plus se limiter à une détection et une manipulation du spin optique, mais ouvre également la possibilité de le faire en modulant le champ de contrainte.Par des expériences de photoluminescence résonante, nous montrons l’existence de niveaux optique en Λ dans les boîtes quantiques chargées positivement et dopées d’un unique atome de Mn. Ces niveaux en Λ sont utilisés pour étudier la dynamique du spin hybride trou-Mn. Cette étude révèle l’existence de flip-flops des spins du trou et du Mn à l’échelle de la nanoseconde, dus à l’interaction d’échange trou-Mn et à l’interaction avec les phonons acoustiques. Un couplage par l’anisotropie des contraintes dans le plan de niveaux électron-Mn dégénérés et séparé par un spin flip de deux unités est aussi démontré, et dynamique cohérente induite par les contraintes est étudiée en détail.Grâce à des expériences magnéto-optiques, nous avons pu détecter la photoluminescence d’un atome de Cr unique dans une boîte quantique, et extraire une anisotropie magnétique du spin du Cr de quelques meV. De nombreux paramètres des boîtes étudiées peuvent être extrait de ces expériences, et nous montrons notamment que le couplage trou-Cr est antiferromagnétique. Nous démontrons que le spin du Cr peut être préparé par pompage optique résonant. Ces expériences ont permis de montrer que, sous excitation, le spin du Cr fait des flip-flops avec celui du trou, causé par l’interaction d’échange trou-Cr et le couplage aux phonons acoustiques. Ces flip-flops causent une relaxation rapide du spin du Cr sous excitation, mesurée comme de l’ordre de quelques dizaines de nanosecondes. Dans le noir, nous avons trouvé que le spin du Cr relaxe en quelques microsecondes. Finalement, nous avons aussi démontré la possibilité de contrôler le spin du Cr par l’effet Stark optique.
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