Coulomb interaction in the spin Hall effect

The influence of the electronic Coulomb interaction on the spin-orbit-coupling induced spin Hall effect was discussed. It was shown that the electronic Coulomb interaction may decrease substantially the spin-orbit-coupling induced transverse spin accumulation in a sample when a longitudinal charge current circulates in it, and the decrease of the transverse spin accumulation due to the influences of the Coulomb interaction is determined by the ratio of the spin-drag resistivity to the ordinary resistivity of the sample.published_or_final_versio

Influence of spin transfer and contact resistance on measurement of the spin Hall effect

When a longitudinal spin-unpolarized charge current flows in a thin slab of nonmagnetic metal with strong spin-orbit coupling of conduction electrons, a transverse spin Hall voltage can be generated between both edges of the sample, and the spin Hall voltage can be detected by the measurement of an ordinary Hall voltage produced in a transverse metal strip which connects both edges of the sample. In this paper, we discuss the influences of spin transfer and contact resistances between the longitudinal sample and the transverse metal strip on the measurement of the spin Hall voltage. We show that, due to the spin transfer between the longitudinal sample and the transverse metal strip, the magnitude of the spin Hall voltage produced in the longitudinal sample and the magnitude of the ordinary Hall voltage produced in the transverse metal strip and the relation between them will all strongly depend on the contact resistances, thus in order to detect the spin Hall voltage correctly through the measurement of the ordinary Hall voltage, the influences of spin transfer and contact resistance need to be taken into account.published_or_final_versio

Experimental study on the inhibitory effect of sodium cantharidinate on human hepatoma HepG2 cells

Backgroud: Cantharidin, and its derivatives can not only inhibit the proliferation of tumor cells, but can also induce tumor cell apoptosis. It shows cantharidin exhibits a wide range of reactivity in anticancer. The objective of this paper was to study the inhibitory effect of sodium cantharidinate on human hepatoma HepG2 cells.Materials and Methods: MTT assay was used to detect the proliferation of HepG2 cells, and immunohisto-chemical method was used to detect the change in VEGF, protein level, and to determine the inhibitory effect of sodium cantharidinate on human hepatoma HepG2 cells.Results: As results, sodium cantharidinate significantly inhibited the growth of HepG2 cells in a time-and dose-dependent manner.Conclusion: We conclude that sodium cantharidinate has an inhibitory effect on human hepatoma HepG2 cells.Key words: sodium cantharidinate; human hepatoma HepG2; MTT assa

Inhibition of the tyrosine phosphatase SHP-2 suppresses angiogenesis in vitro and in vivo

Endothelial cell survival is indispensable to maintain endothelial integrity and initiate new vessel formation. We investigated the role of SHP-2 in endothelial cell survival and angiogenesis in vitro as well as in vivo. SHP-2 function in cultured human umbilical vein and human dermal microvascular endothelial cells was inhibited by either silencing the protein expression with antisense-oligodesoxynucleotides or treatment with a pharmacological inhibitor (PtpI IV). SHP-2 inhibition impaired capillary-like structure formation (p < 0.01; n = 8) in vitro as well as new vessel growth ex vivo (p < 0.05; n = 10) and in vivo in the chicken chorioallantoic membrane (p < 0.01, n = 4). Additionally, SHP-2 knock-down abrogated fibroblast growth factor 2 (FGF-2)-dependent endothelial proliferation measured by MTT reduction ( p ! 0.01; n = 12). The inhibitory effect of SHP-2 knock-down on vessel growth was mediated by increased endothelial apoptosis ( annexin V staining, p ! 0.05, n = 9), which was associated with reduced FGF-2-induced phosphorylation of phosphatidylinositol 3-kinase (PI3-K), Akt and extracellular regulated kinase 1/2 (ERK1/2) and involved diminished ERK1/2 phosphorylation after PI3-K inhibition (n=3). These results suggest that SHP-2 regulates endothelial cell survival through PI3-K-Akt and mitogen-activated protein kinase pathways thereby strongly affecting new vessel formation. Thus, SHP-2 exhibits a pivotal role in angiogenesis and may represent an interesting target for therapeutic approaches controlling vessel growth. Copyright (C) 2007 S. Karger AG, Basel

Ca2+ Cycling in Heart Cells from Ground Squirrels: Adaptive Strategies for Intracellular Ca2+ Homeostasis

Heart tissues from hibernating mammals, such as ground squirrels, are able to endure hypothermia, hypoxia and other extreme insulting factors that are fatal for human and nonhibernating mammals. This study was designed to understand adaptive mechanisms involved in intracellular Ca2+ homeostasis in cardiomyocytes from the mammalian hibernator, ground squirrel, compared to rat. Electrophysiological and confocal imaging experiments showed that the voltage-dependence of L-type Ca2+ current (ICa) was shifted to higher potentials in ventricular myocytes from ground squirrels vs. rats. The elevated threshold of ICa did not compromise the Ca2+-induced Ca2+ release, because a higher depolarization rate and a longer duration of action potential compensated the voltage shift of ICa. Both the caffeine-sensitive and caffeine-resistant components of cytosolic Ca2+ removal were more rapid in ground squirrels. Ca2+ sparks in ground squirrels exhibited larger amplitude/size and much lower frequency than in rats. Due to the high ICa threshold, low SR Ca2+ leak and rapid cytosolic Ca2+ clearance, heart cells from ground squirrels exhibited better capability in maintaining intracellular Ca2+ homeostasis than those from rats and other nonhibernating mammals. These findings not only reveal adaptive mechanisms of hibernation, but also provide novel strategies against Ca2+ overload-related heart diseases

Direct Measurement of B(D0->phiX0) and B(D+->phiX+)

The first measurement of B(0->phi X0) and an upper limit for B(D+->phi X+) are determined from 22.3 pb-1 of e+e- annihilation data at a C. M. energy of 4.03 GeV. The data were recorded by the Beijing Spectrometer (BES) at BEPC. A recoil charge method is applied for the first time to charm threshold data to determine the charge of the D meson in the recoil from 9054+-309+-416 reconstructed D0, D+ mesons. The branching fractions B(D->phiX0) =(1.71+0.76-0.71+-0.17)%, and B(D+->phiX+) <1.8% are determined from 10 events with a reconstructed D and a recoiling phi. In addition, a 90% C.L. upper limit of B(D+->phi e+X0)<1.6% is determined from a search for semileptonic decays of the D+.Comment: Submitted to Phys. Rev.

Observation of a ppb mass threshoud enhancement in \psi^\prime\to\pi^+\pi^-J/\psi(J/\psi\to\gamma p\bar{p}) decay

The decay channel $\psi^\prime\to\pi^+\pi^-J/\psi(J/\psi\to\gamma p\bar{p})$ is studied using a sample of $1.06\times 10^8$ $\psi^\prime$ events collected by the BESIII experiment at BEPCII. A strong enhancement at threshold is observed in the $p\bar{p}$ invariant mass spectrum. The enhancement can be fit with an $S$-wave Breit-Wigner resonance function with a resulting peak mass of $M=1861^{+6}_{-13} {\rm (stat)}^{+7}_{-26} {\rm (syst)} {\rm MeV/}c^2$ and a narrow width that is $\Gamma<38 {\rm MeV/}c^2$ at the 90% confidence level. These results are consistent with published BESII results. These mass and width values do not match with those of any known meson resonance.Comment: 5 pages, 3 figures, submitted to Chinese Physics

Generalized linear model for interval mapping of quantitative trait loci

We developed a generalized linear model of QTL mapping for discrete traits in line crossing experiments. Parameter estimation was achieved using two different algorithms, a mixture model-based EM (expectation–maximization) algorithm and a GEE (generalized estimating equation) algorithm under a heterogeneous residual variance model. The methods were developed using ordinal data, binary data, binomial data and Poisson data as examples. Applications of the methods to simulated as well as real data are presented. The two different algorithms were compared in the data analyses. In most situations, the two algorithms were indistinguishable, but when large QTL are located in large marker intervals, the mixture model-based EM algorithm can fail to converge to the correct solutions. Both algorithms were coded in C++ and interfaced with SAS as a user-defined SAS procedure called PROC QTL