Search Results - (Author, Cooperation:X. Cheng)

2018-06-07

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2041-1723

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2018-06-08

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0036-8075

1095-9203

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2018-03-22

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2018-03-31

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2044-6055

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2018-02-22

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1755-1307

1755-1315

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2018-02-09

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2014-02-22

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Animals ; Antibodies, Monoclonal ; Antiviral Agents/*pharmacology/therapeutic use ; Cell Line ; Cell Nucleus/virology ; Cytidine/metabolism ; Cytidine Deaminase/biosynthesis ; DNA, Circular/*metabolism ; DNA, Viral/*metabolism ; Hepatitis B/*drug therapy ; Hepatitis B virus/*drug effects/metabolism ; Hepatocytes/*drug effects/metabolism/virology ; Humans ; Interferon-alpha/*pharmacology/therapeutic use ; Liver/drug effects/metabolism/virology ; Lymphotoxin beta Receptor/*agonists/antagonists & inhibitors ; Mice, SCID ; Proteins ; Up-Regulation

2015-11-28

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3T3-L1 Cells ; Animals ; Biology ; Gases ; Humans ; Medicine ; Mice ; Microscopy/*methods ; Molecular Imaging/*methods ; Sensitivity and Specificity ; Spectrum Analysis, Raman/*methods ; Vibration

2014-01-07

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0028-0836

1476-4687

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5-Methylcytosine/chemistry/*metabolism ; Amino Acid Sequence ; Animals ; Catalytic Domain/genetics ; Conserved Sequence ; Crystallography, X-Ray ; Cytosine/analogs & derivatives/metabolism ; DNA/*chemistry/*metabolism ; DNA-Binding Proteins/chemistry/genetics/metabolism ; Dioxygenases/*chemistry/*metabolism ; Escherichia coli Proteins/chemistry ; HEK293 Cells ; Humans ; Hydrogen Bonding ; Mice ; Mixed Function Oxygenases/chemistry ; Models, Molecular ; Molecular Sequence Data ; Naegleria/*enzymology/genetics ; Proto-Oncogene Proteins/chemistry/genetics/metabolism ; Structural Homology, Protein ; Structure-Activity Relationship ; Substrate Specificity

2014-07-22

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Alleles ; Antigenic Variation/genetics ; Chromatin/enzymology ; Down-Regulation/genetics ; Erythrocytes/parasitology ; Exoribonucleases/deficiency/genetics/*metabolism ; *Gene Silencing ; Genes, Protozoan/*genetics ; Humans ; Introns/genetics ; Malaria, Cerebral/*parasitology ; Malaria, Falciparum/parasitology ; Plasmodium falciparum/*enzymology/*genetics/pathogenicity ; Promoter Regions, Genetic/genetics ; Protozoan Proteins/genetics ; RNA, Messenger/genetics/metabolism ; RNA, Protozoan/genetics/*metabolism ; RNA, Untranslated/genetics/metabolism ; Transcription Initiation Site ; Virulence/genetics ; Virulence Factors/genetics

2011-09-03

American Association for the Advancement of Science (AAAS)

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2013-01-22

Nature Publishing Group (NPG)

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1476-4687

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Animals ; B-Lymphocytes/immunology/metabolism ; Bacteria/immunology ; Cells, Cultured ; Endopeptidases/deficiency/genetics/*metabolism ; Female ; Fibroblasts ; HEK293 Cells ; Homeostasis ; Humans ; Intestines/immunology ; Male ; Mice ; NF-kappa B/*metabolism ; Proteolysis ; Receptors, Cell Surface/metabolism ; TNF Receptor-Associated Factor 3/*metabolism ; *Ubiquitination

1089-7550

AIP Digital Archive

Physics

We report on tunnel switch diodes based on AlSb barriers and GaSb p–n junctions grown by molecular beam epitaxy. These were the devices with thyristor like switching in the GaSb/AlSb system. The characteristic "S" shaped current–voltage curve was found to occur for structures with AlSb barriers less than 300 Å thick. The switching voltage and current density exhibited less sensitivity to barrier and epilayer thickness than was predicted by the punch-through model. The results were correlated with drift diffusion simulations which have been modified to account for the presence of a tunneling contact. © 2000 American Institute of Physics.

Electronic Resource

1089-7550

AIP Digital Archive

Physics

In this paper, we report the observation, through optical microscopy, of drumhead-like patterns in square and circular mesas which have been wet thermally oxidized to completion. Micro-Raman spectroscopy measurements are used to show that these patterns roughly correspond to variations in strain induced in surrounding semiconductor layers by the oxidation process. In addition, the patterns have a specific orientation with respect to the crystallographic axes of the semiconductor. A crystallographic dependence of the oxidation process itself is demonstrated and used to explain the orientation of the drumhead patterns. © 2000 American Institute of Physics.

Electronic Resource

1089-7550

AIP Digital Archive

Physics

The crystal structure and magnetic properties of LaCo13−x−yFexSiy compounds were investigated by means of x-ray powder diffraction and magnetization measurements. The substitution of Si for Co induces an order–disorder transition from the cubic NaZn13-type to its tetragonal derivative structure, while the substitution of Fe for Co does not induce such a phase transition. After annealing treatment, the homogeneous range of the cubic phase is narrowed and that of the tetragonal phase is extended. From crystallographic and thermodynamic points of view, the sta- bility of the cubic and the tetragonal phases is discussed. The measured magnetic moment of LaCo13−x−yFexSiy coincides well with the theoretical prediction based on the magnetic valence model. Within the framework of this model, LaCo13−x−yFexSiy compounds can be considered as strong ferromagnets and their magnetic moment can be theoretically predicted. The composition dependence of Curie temperature is discussed within the mean field approximation. At higher iron concentration the decrease of Curie temperature with Fe concentration might be attributed to the increase of the number of antiferromagnetically coupled Fe–Fe pairs and the decrease of the ferromagnetic coupling between transition metal atoms. © 1996 American Institute of Physics.

Electronic Resource

1089-7550

AIP Digital Archive

Physics

We have investigated the wet thermal oxidation of AlAs in cylindrical geometry, a typical configuration for vertical-cavity surface-emitting lasers. Through both experiment and theoretical calculations, we demonstrate a significantly different time dependence for circular mesas from what has been reported in the literature both in studies of stripes and in a study of circular mesas. We attribute this different time dependence to the effect of geometry on the oxidation. © 1998 American Institute of Physics.

Electronic Resource

1089-7550

AIP Digital Archive

Physics

We demonstrate the use of bulk Al0.04Ga0.96Sb and GaSb/AlSb superlattice as the gain material in a separate absorption/multiplication avalanche photodiode with sensitivity up to 1.74 μm. Both gain schemes were implemented in a molecular-beam epitaxy grown structure with a selectively doped InAs/AlSb superlattice as the n-type layer. Hole impact ionization enhancement was observed in Al0.04Ga0.96Sb by using a two wavelength injection scheme. The superlattice gain layer device exhibited multiplication factors in excess of 300, and surface limited dark current at a level comparable to InGaAs/InAlAs devices of similar design. The superlattice gain layer was found to be more promising than its bulk counterpart due to its inherent lower dark current. © 1999 American Institute of Physics.

Electronic Resource

1089-7550

AIP Digital Archive

Physics

Conduction enhancement characteristics and the conduction mechanism in nitroxide are reported in this paper. Thermally grown oxides with various thicknesses were nitrided in pure ammonia for different nitridation times. Conduction in thick oxide after short-time nitridation is dominated by Fowler–Nordheim tunneling with lowered barrier height. A trap-assisted tunneling model was used to explain the effect of the degree of nitridation on current enhancement in heavily nitrided films. A theoretical calculation was carried out to fit the theory to the experimental results, and the trap density and trap energy level were found to be in the ranges of 1.2×1019–7.2×1020 cm−3 and 2.46–2.56 eV, respectively. These results are explained satisfactorily by the Auger spectroscopic data.

Electronic Resource

1077-3118

AIP Digital Archive

Physics

Tetragonal LaCo13−xSix compounds have been obtained by annealing cubic LaCo13−xSix compounds. The space group for the tetragonal structure is I4/mcm. Atomic ordering occurs in the tetragonal LaCo13−xSix compounds, i.e., Si atoms show a strong preference for occupying a specific crystallographic position. The tetragonal LaCo13−xSix compounds are ferromagnetic with Curie temperatures higher than 900 K. The magnetic moment per Co atom in the tetragonal LaCo13−xSix compounds decreases with Si content, which can be explained by the rigid-band model. The tetragonal LaCo13−xSix compounds are expected to be promising candidates for permanent magnets purpose.

Electronic Resource

1077-3118

AIP Digital Archive

Physics

A magnetoresistance ratio as high as −96% in a low field of 0.67 T is achieved in bulk La1/3Nd1/3Ca1/3MnO3. The magnetization exhibits a transition from a low moment state to a high moment state with decreasing temperature, accompanied by a thermal hysteresis of the magnetization. The magnetic transition might be an order-order transition and would be responsible for the observed giant magnetoresistance effect in the compound at low field. © 1996 American Institute of Physics.

Electronic Resource