Search Results - (Author, Cooperation:S. Duan)

2018-04-21

American Association for the Advancement of Science (AAAS)

2375-2548

Natural Sciences in General

2011-11-25

Nature Publishing Group (NPG)

0028-0836

1476-4687

Biology

Chemistry and Pharmacology

Medicine

Natural Sciences in General

Physics

Alleles ; Animals ; Apoptosis ; Cell Line, Tumor ; Cell Proliferation ; DNA-Binding Proteins/genetics/*metabolism ; F-Box Proteins/*genetics/*metabolism ; Gene Deletion ; Genes, Tumor Suppressor ; HEK293 Cells ; Humans ; Lymphoma, Large B-Cell, Diffuse/enzymology/*genetics/*metabolism/pathology ; Mice ; Mutation/*genetics ; Neoplasm Transplantation ; Proteasome Endopeptidase Complex/metabolism ; Protein Stability ; Protein-Arginine N-Methyltransferases/deficiency/*genetics/*metabolism ; *Proteolysis ; SKP Cullin F-Box Protein Ligases/metabolism ; Ubiquitination

2014-08-02

American Association for the Advancement of Science (AAAS)

0036-8075

1095-9203

Biology

Chemistry and Pharmacology

Computer Science

Medicine

Natural Sciences in General

Physics

2015-05-02

American Association for the Advancement of Science (AAAS)

0036-8075

1095-9203

Biology

Chemistry and Pharmacology

Computer Science

Medicine

Natural Sciences in General

Physics

Aging/genetics/*metabolism ; Animals ; *Cell Aging ; Cell Differentiation ; Centromere/metabolism ; Chromosomal Proteins, Non-Histone/metabolism ; DNA-Binding Proteins/metabolism ; Epigenesis, Genetic ; Exodeoxyribonucleases/genetics/*metabolism ; Gene Knockout Techniques ; HEK293 Cells ; Heterochromatin/chemistry/*metabolism ; Humans ; Membrane Proteins/metabolism ; Mesenchymal Stromal Cells/*metabolism ; Methyltransferases/genetics/metabolism ; Mice ; Models, Biological ; RecQ Helicases/genetics/*metabolism ; Repressor Proteins/genetics/metabolism ; Werner Syndrome/genetics/*metabolism

1089-7550

AIP Digital Archive

Physics

This paper reports on two thin-film media alloys Co86Cr12Ta2 and Co75Ni25 which have very different noise characteristics. The magnetic microstructure of these films was observed with scanning electron microscopy with polarization analysis (SEMPA). The variance (σ 2t) of the magnetization across the transition region was calculated. The origin of anisotropy was determined by measuring the temperature coefficients of Hc and Ms. The interaction strengths between grains, δM(H), were obtained from the measurements of the reverse demagnetization remanence Md(H) and the forward magnetization remanence Mr(H). We found that the CoNi film showed a greater degree of interparticle interaction, which may explain the observed cross-bit linkages in SEMPA image, larger rms transition variation (σt), and higher modulation noise.

Electronic Resource

1089-7550

AIP Digital Archive

Physics

The changes in the magnetic properties of CoNiCr/Cr thin films with annealing are found to depend not only on the annealing conditions but also on the Cr underlayer thickness dCr. After vacuum anneal, the in-plane coercivity Hc increased initially with total annealing time τa and then leveled off. The Hc increase was greater at higher annealing temperatures Ta and in samples with thicker Cr underlayers. Hc values as high as 1800 Oe were obtained. The squareness S* decreased with τa, and the saturation magnetization Ms decreased slightly with τa. No significant change was found in the grain size and the crystal texture of the films after annealing, regardless of the Cr underlayer thickness. However, for the sample with a large Hc increase following anneal, it was found that the corresponding Lorentz micrograph image changed dramatically. TEM x-ray energy dispersive data indicated that the Cr concentration in the CoNiCr layer increased after anneal. The changes in Hc, S*, and Ms following air anneal were similar to those found following vacuum anneal. However, at the same Ta, the increase in Hc was less; also Ms was found to decrease noticeably. We believe that the changes in magnetic properties following anneal are associated with increased Cr content in the grain boundaries.

Electronic Resource

1089-7550

AIP Digital Archive

Physics

The large difference in coercivities between CoNiCr (800 Oe) and CoFeCr (200 Oe) thin films, which were deposited on Cr-coated NiP/Al substrates under the same conditions, is related to their differences in microstructures. The magnetic properties were measured with a vibrating sample magnetometer and the microstructures were studied by transmission electron microscopy. It is found that both the CoNiCr and the CoFeCr films are hcp in phase, and of similar grain sizes. However, the stacking fault density (fcc region) is higher in CoNiCr films than in CoFeCr films, which may account for the difference in their coercivities. The presence of stacking faults is related to composition effects on stacking fault energy and their generation to release residual stresses.

Electronic Resource

1089-7550

AIP Digital Archive

Physics

The crystallographic texture of Cr film deposited on glass substrates is found to depend on the film thickness dCr and the substrate temperature Ts. Without substrate preheating, only the Cr {110} peak was observed in the x-ray diffraction spectra for films between 60 and 400 nm in thickness. With increasing Ts (by substrate preheating), the Cr{200} peak became observable at progressively increasing intensity, whereas the intensity of the {110} peak decreased. Consequently the 170-nm-thick films deposited at Ts ≥200 °C are predominantly {100} textured. However, even for these high Ts values (≥200 °C), the {110} peak intensity increases with increasing film thickness. Larger film thickness values are required at higher Ts for the {110} texture to overcome the {100} texture. The grain size of the Cr films deposited on glass increases with film thickness and with substrate temperature.

Electronic Resource

1089-7550

AIP Digital Archive

Physics

Recently, there has been much interest in the noise characteristics of recording media.1 These characteristics have not been completely explained by current theoretical models.2 This paper reports on the noise characteristics as a function of write current and its correlation with written bits as observed by SEMPA.3–5 CoNiCr film sputtered on Al-based NiP substrate was used for this study. The grain structure of this sample was obtained by high-resolution SEM, and the magnetic microstructure was observed by utilizing the SEMPA technique. The saturation magnetization MS and coercivity HC for this film are 731 emu/cc and 794 Oe, respectively. The noise measurements show that as the write current is increased from zero, a well-defined noise maximum is observed at a write current of about 8.5 mA o-p. With further increase in write current, noise voltage decreases to a minimum at about 14 mA o-p, and then rises again showing a secondary, broad noise maximum at a write current of about 34 mA o-p. The SEMPA images of the written transitions at those three write currents of 8.5, 14, and 34 mA o-p have been obtained. These SEMPA images show a strong correlation with the noise behavior of this media. At the first noise maxima, where the signal amplitude is high, the magnetized regions show some cross links and the transition region shows irregularities. For the intermediate write current where noise is low, the cross links between the magnetized regions are minimal. At the secondary maximum, where the readback signal amplitude is very low, the magnetized regions are heavily overlapped and there is practically no identifiable transition regions as observed by SEMPA. The micromagnetic structure of a reverse dc erase track at the noise maximum has also been observed by SEMPA and will be reported along with the noise data.5 The details of this paper appear in Ref. 5.〈ks〉

Electronic Resource

1077-3118

AIP Digital Archive

Physics

We report that in BaTiO3:Rh the carrier-type depends not only on the postprocessing condition but also on the incident wavelength in two beam coupling. Carriers are the holes for the as-grown sample, and change to electrons for the sample reduced in the atmosphere of 10−14 atm oxygen partial pressure. However, for the sample reduced in the atmosphere of 10−10 atm oxygen partial pressure, the carrier is an electron for the incident wavelength of 514 nm, and a hole for 633 nm. Its absorption, photoinduced absorption, and two beam coupling are investigated and discussed. © 1998 American Institute of Physics.

Electronic Resource

1077-3118

AIP Digital Archive

Physics

Time-resolved photoluminescence (PL) spectroscopy has been used to study the radiative recombination of excitons bound to ionized donors in GaN doped with both Mg and Si at concentrations of 5×1018/cm3 and 1.5×1017/cm3, respectively. Low temperature (T∼10K) time-resolved, as well as integrated PL spectra, identify an ionized donor-bound (Si) exciton peak (D+X) approximately 11.5 meV below and a neutral acceptor-bound exciton (A0X) 20.5 meV below the free exciton peak. Rapid decay of the free exciton emission (≤20 ps) implies that excitons are quickly captured by acceptors and ionized donors. We find the (A0X) emission lifetime is consistent with previous measurements for GaN:Mg epilayers, while the (D+X) lifetime of 160 ps is longer than that of the well studied neutral donor-bound exciton (D0X). The measured (D+X) lifetime, in comparison with (D0X) and (A0X), suggests that the state is stable at low temperature. © 1999 American Institute of Physics.

Electronic Resource

1077-3118

AIP Digital Archive

Physics

Spin-polarized secondary electron microscope images of tracks of magnetic domains, written in Co62.5Ni30Cr7.5 thin-film longitudinal recording media, are presented as a function of write current. The corresponding modulation noise measurements are also presented for this sample. We observe that the magnetic microstructure visible in the images can be correlated with the modulation noise in each region of write current investigated. Explanations for the possible origins of this microstructure are presented.

Electronic Resource

1600-0668

Blackwell Publishing Journal Backfiles 1879-2005

Architecture, Civil Engineering, Surveying

Medicine

Electronic Resource

0304-8853

Elsevier Journal Backfiles on ScienceDirect 1907 - 2002

Physics

Electronic Resource

1572-8838

Springer Online Journal Archives 1860-2000

Chemistry and Pharmacology

Electrical Engineering, Measurement and Control Technology

Electronic Resource

1432-1041

Key words Human CYP3A ; Amprenavir ; Ritonavir

Springer Online Journal Archives 1860-2000

Chemistry and Pharmacology

Medicine

Abstract Objective: Biotransformation of triazolam to its α-hydroxy and 4-hydroxy metabolites by human liver microsomes in vitro was used as an index of human cytochrome P 450 3A (CYP3A) activity. Results: The reaction was strongly inhibited by co-incubation with the viral protease inhibitors ritonavir (IC50=0.14 μM) and amprenavir (IC50=2.5–2.9 μM), and by the azole derivative ketoconazole (IC50 = 0.07 μM). Pre-incubation of microsomes with ritonavir or amprenavir increased inhibitory potency (IC50 reduced to 0.07 μM and 1.4 μM, respectively). This was not the case with ketoconazole. Conclusions: Thus, ritonavir and amprenavir are highly potent mechanism-based inhibitors of human CYP3A isoforms.

Electronic Resource

1573-5060

peanut ; gynophore culture ; intersectional hybrid ; Arachis hypogaea

Springer Online Journal Archives 1860-2000

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

Summary Cross-incompatibility between cultivated peanuts and their wild relatives outside the section Arachis has impeded the utilization of many species possessing high resistances or good qualities. Despite the great efforts made to culture immature ovules or embryos, few hybrid offspring have been obtained. In this study, gynophores from Arachis hypogaea L. pollinated with A. glabrata Benth. were cultured and F1 hybrids seeds were harvested, and F2 and F3 generations produced. The characters of F2 generation exhibited a wide range of segregation. Leaf peroxidase isozyme PAGE analysis revealed that the hybrids were quite different from their parents in relation to band number, width and isozyme activity. The zymograms of the hybrids and their parents were partially alike. This verified the authenticity of the hybrids.

Electronic Resource

1435-5663

Key words. Distributed memory; Low order algorithm; Multibody dynamics; Parallel computing

Springer Online Journal Archives 1860-2000

Computer Science

Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics

Technology

Abstract. In this paper, a new hybrid parallelisable low order algorithm, developed by the authors for multibody dynamics analysis, is implemented numerically on a distributed memory parallel computing system. The presented implementation can currently accommodate the general spatial motion of chain systems, but key issues for its extension to general tree and closed loop systems are discussed. Explicit algebraic constraints are used to increase coarse grain parallelism, and to study the influence of the dimension of system constraint load equations on the computational efficiency of the algorithm for real parallel implementation using the Message Passing Interface (MPI). The equation formulation parallelism and linear system solution strategies which are used to reduce communication overhead are addressed. Numerical results indicate that the algorithm is scalable, that significant speed-up can be obtained, and that a quasi-logarithmic relation exists between time needed for a function call and numbers of processors used. This result agrees well with theoretical performance predictions. Numerical comparisons with results obtained from independently developed analysis codes have validated the correctness of the new hybrid parallelisable low order algorithm, and demonstrated certain computational advantages.

Electronic Resource

2018-02-25

BMJ Publishing

2044-6055

Medicine

Open access, Renal medicine