Wyniki wyszukiwania - Biblioteka Nauki

1

High-Pressure Phase Transitions and Thermodynamic Behaviors of Cadmium Sulfide

100%

Tan J. , Li Y. , Ji G.

Acta Physica Polonica A

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2011

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tom 120

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nr 3

501-506

EN

The pressure-induced phase transitions of cadmium sulfide semiconductor in both zinc-blende and wurtzite structures are investigated by ab initio plane-wave pseudopotential density functional theory with the local density approximation. On the basis of the fourth-order Birch-Murnaghan equation of state, the phase transition pressures P_{t} are determined by the enthalpy criterion. It is found that the phase transitions occur at pressure of 2.57 GPa (zinc blende-rocksalt structure) and 2.60 GPa (wurtzite-rocksalt structure), respectively. The equilibrium structural parameters, elastic constants, and phase transition pressures are calculated and compared with the experimental data available and other theoretical results. According to linear-response approach, the thermodynamic properties such as the free energy, enthalpy, entropy, and heat capacity are also obtained successfully from the phonon density of state.

2

Mechanisms of type I interferon signaling in normal and malignant cells

100%

Li Y. , Srivastava K. K. , Platanias L. C.

Archivum Immunologiae et Therapiae Experimentalis

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2004

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tom 52

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nr 3

156-163

EN

Type I interferons (IFNs) are cytokines that induce multiple biological effects on target cells, including antiviral, antiproliferative, and immunomodulatory activities. Consistent with the pleiotropic nature of these cytokines, multiple signaling pathways are activated during binding of IFNs to the type I IFN receptor. An important signaling cascade activated by type I IFNs is the Jak-Stat pathway. Activation of the Tyk-2 and Jak-1 kinases, and downstream formation of various Stat complexes, mediates IFN-dependent gene transcription for IFN-stimulated genes. In addition to the classic Jak-Stat pathway, type I IFNs activate multiple other pathways, including the insulin receptor substrate-phosphatidylinositol 3'-kinase cascade, the CBL-CrkL pathway, and mitogen-activated protein kinase pathways. There is accumulating evidence that non-Stat IFN-regulated signaling pathways play important roles in the generation of the antiproliferative effects of type I IFNs. In this review, the regulation of various signaling cascades by the type I IFN receptor is summarized and an update on recent advances in the field is provided.

3

Simulation of electrostatic field in electrospinning of polymer nanofibers

100%

Li Y. , Zhang X. , Trudick E. , Chase G. G.

Nanoscale Systems: Mathematical Modeling, Theory and Applications

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2015

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tom 4

|

nr 1

EN

Electrospinning is a popular process for fabricating submicron diameter gibers. The process applies a strong electric gield to launch a polymer jet that elongates to create the gine gibers. The jet dries as the solvent evaporates and the dried giber collects on a grounded surface. Most of electrospinning literatures focus the polymer solution compositions and the properties of the produced gibers. Less attention is applied to the electrostatic gield geometries and operating conditions. Through computer simulations and laboratory experiments thiswork shows that by applying the grounded voltage to different regions of the collector surface, the electric gield can be moved spatially to direct the electrospinning jets towards select locations of the grounded surface.

4

Phase Transition in Quasi-Two-Dimensional Horizontally Driven Granular System

88%

Shah S. , Li Y. , Khan W. , Din N. , Chand R.

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nr 3

699-702

EN

In an experimental setup, consisting of quasi-two-dimensional square cell, the motion of monodisperse spherical steel balls is studied. The cell is vibrated horizontally to eradicate the compaction of balls due to gravity. By raising the number density of the steel balls, the dilute fluid has been gradually alternated into dense fluid. The temperature of granular media, along the driven and transverse directions, has been found to be anisotropic. Transition from granular gas to the liquid-like fluid has been observed. The radial distribution function of the balls in the cell is investigated for the authentication of the structural changes. Furthermore, the fast Fourier transformation for the 2D system is carried out to confirm these changes.

5

Influence of dent corn genetic backgrounds on QTL detection for plant-height traits and their relationships in high-oil maize

88%

Wei M. , Fu J. , Li X. , Wang Y. , Li Y.

Journal of Applied Genetics

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2009

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tom 50

|

nr 3

225-234

EN

QTL mapping for plant-height traits has not been hitherto reported in high-oil maize. A high-oil maize inbred 'GY220' was crossed with two dent maize inbreds ('8984' and '8622') to generate two connected F2:3 populations. Four plant-height traits were evaluated in 284 and 265 F2:3 families. Single-trait QTL mapping and multiple-trait joint QTL mapping was used to detect QTLs for the traits and the genetic relationship between plant height (PH) and two other plant-height traits. A total of 28 QTLs and 12 pairs of digenic interactions among detected QTLs for four traits were detected in the two F2:3 families. Only one marker was shared between the two populations. Joint analysis of PH with ear height (EH) and PH with top height (TH) detected 32 additional QTLs. Our results showed that QTL detection for PH was dependent on the genetic background of dent corn inbreds. Multiple-trait joint QTL analysis could increase the number of detected QTLs.

6

Sense and nonsense from whole genome microarray data in the analysis of microbial physiology

88%

Overton T. W. , Whitehead R. , Li Y. , Griffiths L. , Cole J.

Biotechnologia

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2008

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nr 1

15-30

EN

The arrival of the post-genomic era has allowed the regulation of every gene or protein of an organism to be studied at once using microarrays for transcriptomic studies, proteomics to analyse gene products, and metabolomics to study the complete complement of products and intermediary metabolites produced by a single person or a single organism. Too often the results of such enterprises are disappointing either because many of the products cannot be identified, or because they are products of genes of unknown function. Success is far more likely to be achieved if the organism to be exploited is thoroughly understood at the levels of genome organisation, regulation, physiology and biochemistry. Typical questions asked in biotechnology and the biopharmaceutical industries include what genes are expressed ? or not expressed ? when recombinant protein production is induced: can they be manipulated to provide a more productive host; and how do successful pathogens survive in the human body when exposed to oxygen starvation or chemical attack by host defence mechanisms. Examples are given of how whole genome microarray data can reveal mechanisms used by bacteria to survive when they are starved of oxygen; what genes are turned on in response to host defence mechanisms such as nitrosative attack; and how pathogens repair damage inflicted by the host defence mechanisms. Striking similarities and fascinating differences are revealed between two major groups of pathogenic bacteria: enteric bacteria that are able to adapt to life both inside and outside an animal host, and the obligate human pathogen, Neisseria gonorrhoeae. Proteins are identified that provide possible targets for biopharmaceutical intervention, and hence illustrate the potential value of whole-genome transcriptomic approaches to biotechnology.

7

A simplified method for generating oligodendrocyte progenitor cells from neural precursor cells isolated from the E16 rat spinal cord

75%

Fu S. L. , Hu J. G. , Li Y. , Wang Y. X. , Jin J. Q. , Xui X. M. , Lu P. H.

Acta Neurobiologiae Experimentalis

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2007

|

tom 67

|

nr 4

367-377

EN

Conditioned medium obtained from B104 neuroblastoma cells (B104CM) has been used widely for inducing oligodendrocyte progenitor cells (OPCs) from neural precursor cells (NPCs). Our previous studies have demonstrated that E16 rat spinal cord-derived NPCs could be induced to differentiate into OPCs using a combination of B104CM and basic fibroblast growth factor (bFGF). Here we report the development of a more efficient and reliable approach to generate large quantities of highly purified OPCs from spinal cord-derived NPCs using a combination of platelet derived growth factor (PDGF) and bFGF. We demonstrated that, after the two factors application, over 90% cells displayed typical bipolar or tripolar morphology and expressed markers for OPCs including A2B5 (90.36 +/- 4.59%), NG2 (93.63 +/- 3.37%) and platelet derived growth factor alpha receptor (PDGFR; 90.35 +/- 1.95%). Our results indicated that the PDGF/bFGF combination is more efficient in generating OPCs than the B104CM/bFGF. And it is a more potent combination of factors in promoting proliferation of OPCs.

8

Theoretical Predictions of Lattice Parameters and Mechanical Properties of Pentaerythritol Tetranitrate under the Temperature and Pressure by Molecular Dynamics Simulations

75%

Tan J. J. , Hu C. , Li Y. , Ge N. , Chen T. , Ji G.

Acta Physica Polonica A

|

2017

|

tom 131

|

nr 2

318-323

EN

Molecular dynamics simulations with condensed-phase optimized molecular potentials for atomistic simulation studies force field are performed to investigate the structure, equation of state, and mechanical properties of high energetic material pentaerythritol tetranitrate. The equilibrium structural parameters, pressure-volume relationship and elastic constants at ambient conditions agree excellently with experiments. In addition, fitting the pressure-volume data to the Birch-Murnaghan or Murnaghan equation of state, the bulk modulus B₀ and its first pressure derivative B'₀ are obtained. Moreover, the elastic constants are calculated in the pressure range of 0-10 GPa at room temperature and in the temperature range of 200-400 K at the standard pressure, respectively. By the Voigt-Reuss-Hill approximation, the mechanical properties such as bulk modulus B, shear modulus G, and the Young modulus E are also obtained successfully. The predicted physical properties under temperature and pressure can provide powerful guidelines for the engineering application and further experimental investigations.

9

Erythropoietin preconditioning suppresses neuronal death following status epilepticus in rats

75%

Yang J. , Huang Y. , Yu X. , Sun H. , Li Y. , Deng Y.

Acta Neurobiologiae Experimentalis

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2007

|

tom 67

|

nr 2

141-148

EN

Status epilepticus (SE) is a grave condition in which the brain undergoes lasting seizures which can lead to neuronal loss. Our previous study suggested that preconditioning with erythropoietin (Epo) suppressed neuronal apoptosis in hippocampus of rats following SE in vivo by inhibiting caspase-3. In this study, we investigated the mechanisms by which Epo preconditioning may exert its anti-apoptotic effects using a lithium-pilocarpine induced SE model in rats. The effects of Epo on neuronal cell death were evaluated using terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL), and the role of the Bcl-2 protein family, which have been shown to be anti- (Bcl-2, Bcl-w) or pro- (Bid, Bim) apoptotic, was examined with immunofluorescence. We found Epo preconditioning decreased the total number of TUNEL, Bim and Bid positive cells, but increased the total number of Bcl-w and Bcl-2 positive cells. These results suggest that systemic Epo pretreatment protects neurons in an acute phase of SE and may result in further suppression of neuronal apoptosis in hippocampus by regulating the balance between pro- and anti-apoptotic Bcl-2 family proteins.

10

The Design and the First Test Results of a Fast LTD Stage

63%

Chen L. , Zhou L. , Zou W. , Ren J. , Li Y. , Wu S. , Xie W. , Feng S. , Deng J.

Acta Physica Polonica A

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2009

|

tom 115

|

nr 6

1186-1188

EN

Linear transformer driver stages are designed to be used as a primary energy storage in high power pulsed generators. In this report, the design and test results of the linear transformer driver stage prototype that delivers ≈100 kA fast pulse with 133 ns FWHM into a ≈0.87 Ω resistive load are described. This stage consists of 20 (100 kV, 20 nF) storage capacitors that are arranged in 10 identical bricks located evenly around the axis of the stage. Each brick contains two capacitors, a multi-gap switch, and the output connector that transfers the energy to the resistive load. The outer diameter of the stage is ≈1.5 m, at a length of ≈20 cm. The stage is developed to demonstrate the possibility of the fast linear transformer driver technology to create high power pulsed generators.