Search Results - (Author, Cooperation:H. Shim)

2018-10-06

American Physical Society (APS)

1098-0121

1095-3795

Physics

Electronic structure and strongly correlated systems

2011-05-28

American Association for the Advancement of Science (AAAS)

0036-8075

1095-9203

Biology

Chemistry and Pharmacology

Computer Science

Medicine

Natural Sciences in General

Physics

2013-09-03

Nature Publishing Group (NPG)

0028-0836

1476-4687

Biology

Chemistry and Pharmacology

Medicine

Natural Sciences in General

Physics

Amidinotransferases/deficiency/*genetics/metabolism ; Cell Line ; Cholesterol/deficiency/metabolism/pharmacology ; Gene Expression Regulation/*drug effects ; Gene Knockdown Techniques ; Humans ; Hydroxymethylglutaryl-CoA Reductase Inhibitors/*adverse effects/pharmacology ; Lymphocytes/cytology/drug effects/metabolism ; Muscular Diseases/*chemically induced/genetics/metabolism ; Polymorphism, Single Nucleotide/genetics ; Quantitative Trait Loci/*genetics ; Simvastatin/*adverse effects/pharmacology ; Sterol Regulatory Element Binding Proteins/metabolism ; Transcription, Genetic/drug effects

2018-04-13

American Physical Society (APS)

1098-0121

1095-3795

Physics

Electronic structure and strongly correlated systems

1089-7550

AIP Digital Archive

Physics

The voltage dependence of magnetoresistance (MR) and the low-frequency voltage fluctuation were studied in magnetic tunnel junctions with an AlN or an Al2O3 barrier formed by plasma nitridation or oxidation. The junctions consist of free and pinned NiFe layers by a FeMn antiferromagnetic layer. For the Al2O3 junction, the variation of half-reduction voltage of MR is about 50 mV from 401.3 mV in maximum to 351.4 mV in minimum depending upon the oxidation time. For the AlN junction, the less nitrided junction with a nitridation time of 120 s shows the higher-half-reduction voltage by about 100 mV than for optimally nitrided or oxidized ones. From the low-frequency voltage noise data, the less nitrided AlN junction shows larger 1/f noise magnitude compared with other junctions with an optimal condition, implying more defect states in the barrier due to unnitrided Al metals. In order to investigate the influence of nitrogen on ferromagnetic layer, another junction with an Al2O3 barrier was made after the pinned NiFe layer was exposed to N2 plasma for 10 s. This junction reveals a lower MR and worse bias voltage dependence than any junctions studied here. The voltage dependence of MR, therefore, is likely influenced by the interface state rather than the defects in the barrier, although the two factors play an important role in determining MR. © 2002 American Institute of Physics.

Electronic Resource

1077-3118

AIP Digital Archive

Physics

Single crystal 3C-SiC epitaxial films are grown on Si(111) surfaces using tetramethylsilane by rapid thermal chemical vapor deposition. Strong blue/green photoluminescence (PL) was observed at room temperature from the free films of SiC prepared by etching the Si substrate. The main PL peak energy varies from 2.1 to 2.4 eV with full widths at half-maximum between 450 and 500 meV, depending on the growth condition, excitation wavelength and excitation light intensity. A weak peak at 3.0 eV also appeared. The infrared (IR) spectra of free films of SiC exhibit modes associated with CH and OH groups. We also compared PL characteristics of free films of SiC with those from porous SiC produced by anodization of SiC/Si to determine the origin of the PL. Porous SiC shows a PL peak centered at 1.9 eV, different from those in SiC. From the analysis of the IR spectra and scanning electron microscopic images, we tentatively suggest that the origin of the PL from free films of SiC might be associated with an OH group adsorbed on defects or some localized states as is the case for an amorphous SixC1−x alloy. © 1997 American Institute of Physics.

Electronic Resource

1077-3118

AIP Digital Archive

Physics

Hydrogenated amorphous silicon films were deposited on the unstrained and strained Si substrates by an electron cyclotron resonance plasma source. The photoluminescence spectra show that emission energies are different from each other. The redshift of photoluminescence induced by the biaxial tensile stress is increased with decreasing the temperature in the range of 0.11–0.17 eV. The stress effect also enhances the quantum efficiency significantly. The pseudomorphic growth of Si on a relaxed Si0.75Ge0.25 (100) surface provides the strain energy of about 0.17 eV. These comparable results indicate that the shift of emission energy is attributed to the stress effect perturbing the polysilane structure. © 1997 American Institute of Physics.

Electronic Resource

1365-3083

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

We demonstrated that an epitope from the recombinant protective antigen (rPA) of Bacillus anthracis was presented by mature major histocompatibility complex class II (MHC-II) molecules, whereas an epitope from the recombinant virulent (rV) antigen of Yersinia pestis was presented by newly synthesized MHC-II. We addressed which endosomal compartments were involved in the antigen processing of each epitope. Bone-marrow-derived macrophages were subjected to subcellular fractionation; fractions were analysed for the expression of endosomal markers and used as a source of enzyme activity for the processing of rPA and rV antigens. The rPA epitope was productively processed by dense lysosomal fractions and light membrane fractions expressing early endosomal markers Rab5 and early endosomal antigen-1 as well as markers of antigen-presenting compartments (MHC-II, DM, DO and Ii chain). In contrast, the rV epitope was productively processed only by dense fractions with lysosomal activity. No productive antigen-processing activity was associated with fractions of intermediate density expressing Rab7 and Rab9, characteristic of late endosomes. The data suggest that endosomal compartments expressing Rab5 guanosine triphosphatase can productively process protein antigens for presentation by mature MHC class II molecules.

Electronic Resource

1750-3841

Blackwell Publishing Journal Backfiles 1879-2005

Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition

Process Engineering, Biotechnology, Nutrition Technology

To improve the storage stability and achieve controlled release, fish oil containing docosahexaenoic acid was encapsulated using double emulsification and subsequent enzymatic gelation method, using microbial transglutaminase cross-linked proteins. Isolated soy protein was selected as a wall material because it showed better emulsion stability and higher reactivity with MTGase than other proteins. Microcapsules prepared by this method showed a high stability against oxygen and a low water solubility, which subsequently resulted in sustained release of fish oil. Results indicate that this microencapsulation process is suitable for preparing protein-based microcapsules containing sensitive ingredients for controlled release and stability improvement.

Electronic Resource

1612-1112

Column Liquid chromatography ; Column-switching ; Losartan and EXP3174 in plasma

Springer Online Journal Archives 1860-2000

Chemistry and Pharmacology

Summary A new liquid chromatographic method with columnswitching has been developed for the simultaneous determination of losartan and its active metabolite, EXP3174 in rat plasma. The plasma samaple was injected onto a precolumn of Lichroprep RP-8 after dilution with 5% acetonitrile in 50 mM phosphoric acid. Polar plasma components were eluted using this diluent. After valve switching, the concentrated drugs were eluted in the back-flush mode and separated by an Inertsil ODS-2 column with acetonitrile-acetate buffer. The method showed excellent precision, accuracy and speed with detection limit 20 ng mL−1. Total analysis time per sample was less than 40 min and the coefficients of variation for intra and inter-assay were 4.8%. This method has been successfully applied after oral administration of losartan to rat plasma samples.

Electronic Resource

1612-1112

Column liquid chromatography ; Meropenem in rat plasma ; Column-switching

Springer Online Journal Archives 1860-2000

Chemistry and Pharmacology

Summary The purpose of this study was to develop a columnswitching HPLC method for the determination of meropenem in plasma. This method showed excellent precision and accuracy with good sensitivity and speed. The total analysis time per sample was less than 20 min and the mean coefficients of variation for intra- and inter-assay were less than 4.0%. The method has been successfully applied to plasma samples from rats receiving an intraperitoneal injection of meropenem.

Electronic Resource