Structural and optical properties of Cr doped ZnO crystalline thin films deposited by reactive electron beam evaporation technique

ZnO and Cr-doped ZnO thin films are grown on to glass substrates using reactive electron beam(e-beam) evaporation technique.Variation of structural,morphological,and optical properties with Cr doping is investigated.X-ray diffraction(XRD) studies show that the films are polycrystalline in nature with single phase.Energy dispersive spectroscopy(EDS) results demonstrate that Cr ions are substitutionally incorporated into ZnO.Atomic force microscopy(AFM) reveals that the films present a compact surface and root mean squared(RMS) roughness increased with Cr contents.The optical band gap energy Eg of the films has been determined using Transmission data by spectrophotometer and ellipsometry.The band gap energy found to be decreased with increasing Cr doping concentration.The optical constants(refractive index,extinction coefficient) are calculated using ellipsometry and found to increase with Cr doping concentration.     

On the predictability of crude oil market: A hybrid multiscale wavelet approach

Past research indicates that forecasting is important in understanding price dynamics across assets. We explore the potentiality of multiscale forecasting in the crude oil market by employing a wavelet multiscale analysis on returns and volatilities of Brent and West Texas Intermediate crude oil indices between January 1, 2001, and May 1, 2015. The analysis is based on a shift-invariant discrete wavelet transform, augmented by an entropy-based methodology for determining the optimal timescale decomposition under different market regimes. The empirical results show that the five-step-ahead wavelet forecast that is based on volatilities outperforms the random walk forecast, relative to the wavelet forecast that is based on returns. Optimal wavelet causality forecasting for returns is suggested across all frequencies (i.e., daily–yearly), whereas for volatilities it is suggested only up to quarterly frequencies. These results may have important implications for market efficiency and predictability of prices on the crude oil markets.     

The neuronal p35 activator of Cdk5 is a novel F-actin binding and bundling protein

The neuronal Cdk5 activator p35 is involved in a multitude of neuronal activities, including cytoskeletal organization. We show here that p35 directly interacts with filamentous actin (F-actin) but not with monomeric actin (G-actin). Through binding, p35 induces the formation of actin bundles and stabilizes F-actin against dilution-induced depolymerization. p35 forms intermolecular self-associations, suggesting that p35 cross-links actin filaments into bundles via its intermolecular self-association. p35 dimerization and association with F-actin occur at the N-terminal region that is absent in the calpain-cleaved product p25, indicating that such p35 properties are lost by its truncation induced under neurotoxic conditions. Using p35 phosphorylated by Cdk5 and a mutational approach, we demonstrate that the phosphorylation of p35 promotes its homodimerization and p35-induced formation of F-actin bundles. In addition, the phosphorylation regulates p35 distribution to microtubule and actin cytoskeletons. Together, these observations define a novel function for p35 in cytoskeletal regulation.     

A dynamic probabilistic marking approach with multi-tag for tracing ICMP-based DoS attacks

This paper presents a dynamic probabilistic marking algorithm with multiple routing address tags, which allows the victim to traceback the origin of ICMP (Internet Control Message Protocol)-based direct and reflective DoS attacks. The proposed approach makes full use of scalable data space of ICMP packet to achieve multiple information tags. The difference between this proposal and previous proposals lies in two points. First, the number of packets needed by the victim to reconstruct the attack path is greatly reduced because of three key mechanisms: multi-tag, uniform leftover probability, and tag location choice based on the module of accommodated tag numbers within a packet. Second, the true origin of both direct and reflective ICMP-based DoS attacks can be traced.     

中东

Thomson Reuters 发布的全球系列研究报告表明,以阿拉伯、伊朗、土耳其为主的中东国家的科学研究与西文国家相比落后许多.当然,也有部分中东的科学家或研究机构从事着世界一流的研究工作.事实上,论文数量及引文指标都清晰地表明,近10年中东地区的研究工作有了很大的进步,表现出了鼓舞人心的发展趋势.     

PD-1 expression on HIV-specific T cells is associated with T-cell exhaustion and disease progression

Functional impairment of T cells is characteristic of many chronic mouse and human viral infections. The inhibitory receptor programmed death 1 (PD-1; also known as PDCD1), a negative regulator of activated T cells, is markedly upregulated on the surface of exhausted virus-specific CD8 T cells in mice. Blockade of this pathway using antibodies against the PD ligand 1 (PD-L1, also known as CD274) restores CD8 T-cell function and reduces viral load. To investigate the role of PD-1 in a chronic human viral infection, we examined PD-1 expression on human immunodeficiency virus (HIV)-specific CD8 T cells in 71 clade-C-infected people who were naive to anti-HIV treatments, using ten major histocompatibility complex (MHC) class I tetramers specific for frequently targeted epitopes. Here we report that PD-1 is significantly upregulated on these cells, and expression correlates with impaired HIV-specific CD8 T-cell function as well as predictors of disease progression: positively with plasma viral load and inversely with CD4 T-cell count. PD-1 expression on CD4 T cells likewise showed a positive correlation with viral load and an inverse correlation with CD4 T-cell count, and blockade of the pathway augmented HIV-specific CD4 and CD8 T-cell function. These data indicate that the immunoregulatory PD-1/PD-L1 pathway is operative during a persistent viral infection in humans, and define a reversible defect in HIV-specific T-cell function. Moreover, this pathway of reversible T-cell impairment provides a potential target for enhancing the function of exhausted T cells in chronic HIV infection.