Effects of relative orientation of the molecules on electron transport in molecular devices

Effects of relative orientation of the molecules on electron transport in molecular devices are studied by non-equilibrium Green's function method based on density functional theory. In particular, two molecular devices, with the planer Au$_{7}$ and Ag$_{3}$ clusters sandwiched between the Al(100) electrodes are studied. In each device, two typical configurations with the clusters parallel and vertical to the electrodes are considered. It is found that the relative orientation affects the transport properties of these two devices completely differently. In the Al(100)-Au$_7$-Al(100) device, the conductance and the current of the parallel configuration are much larger than those in the vertical configuration, while in the Al(100)-Ag$_{3}$-Al(100) device, an opposite conclusion is obtained

Analysis of Y(4660) and related bound states with QCD sum rules

In this article, we take the vector charmonium-like state Y(4660) as a $\psi'f_0(980)$ bound state (irrespective of the hadro-charmonium and the molecular state) tentatively, study its mass using the QCD sum rules, the numerical value $M_Y=4.71\pm0.26 \rm{GeV}$ is consistent with the experimental data. Considering the SU(3) symmetry of the light flavor quarks and the heavy quark symmetry, we also study the bound states $\psi'\sigma(400-1200)$, $\Upsilon'"f_0(980)$ and $\Upsilon"'\sigma(400-1200)$ with the QCD sum rules, and make reasonable predictions for their masses.Comment: 18 pages, 32 figures, revised versio

Cytotoxicity of Essential Oil of Chenopodium ambrosioides L against Human Breast Cancer MCF-7 Cells

Purpose: To investigate the cytotoxic activity of the essential oil of Chenopodium ambrosioides L. against human breast cancer MCF-7 cells.Methods: Cytotoxicity was characterized by 50 % inhibition (IC50) of human breast cancer cell lines (MCF-7) using 3-(4,5-dimethylthaizol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Apoptosis was analysed by Hoechst33258 staining and DNA ladder. MCF-7 cellular superoxide dismutase (SOD), catalase (CAT) vitality and malondialdehyde (MDA) content were evaluated.Results: The essential oil was cytotoxic to MCF-7 cell line. A dose- and time-dependent inhibition was observed with IC50 values of 18.75, 9.45 and 10.50 μg/ml at 6, 24 and 48 h, respectively. Analyses by Hoechst33258 staining and DNA ladder indicate that the essential oil induced apoptosis. SOD vitality significantly decreased (p＜ 0.05) by 51 % when the concentration of the essential oil increased from 1.25 to 12.5 μg/ml while CAT vitality significantly increased (p ＜ 0.05) by 71 % when essential oil concentration was similarly increased. The MDA content of each treatment group, when compare to control, did not show any significant difference (p ＜ 0.05).Conclusion: The essential oil of C. ambrosioides was cytotoxic to MCF-7 cell line and induced apoptosis.Keywords: Chenopodium ambrosioides L., Essential oil, Cytotoxicity, Apoptosis, Breast cancer, MCF-7 cells

Effects of supplementing lactic acid bacteria on fecal microbiota, total cholesterol, triglycerides and bile acids in rats.

Background: Probiotics (LAB) are normal components of the intestinal micro-flora in both humans and animals and its ingestion in decreasing the risk of atherosclerosis. In addition, the potential health effects of LAB were investigated by monitoring changes in intestinal micro-flora and lipid metabolism in a rat model.Materials and Methods: Rats were randomly assigned into four treatments and fecal samples were obtained on days 1, 3, 5, 9 and 14，to evaluate fecal micro biota, total cholesterol (TC), triglycerides (TG) and bile acids in rats (TBA).Results: The results indicated that Lactobacillus plantarum strain L.p X3-2B increased fecal lactic acid bacteria(LAB) and Bifidobacterium while resisting the growth of harmful bacteria. Viable counts of LAB and Bifidobacterium reached 8 log cfu/mL after feeding for 14 days. Fecal pH in the control group was high in comparison with the treatments at all times. Treatment increased the excretion of triglycerides (TG), total cholesterol (TC) and total bile acid (TBA). The results indicate that LAB and Bifidobacterium induce a positive correlation with fecal TC, TG and TBA and a negative correlation with fecal Enterobacteriaceae, Enterococcus and Escherichia coli.Conclusion: Lactic acid bacteria screened from Inner Mongolia native meat sausages in China had cholesterol-lowering effect.Keywords: Lactic acid bacteria, fecal micro biota, TC, TG, TB

Phenomenological Scaling of Rapidity Dependence for Anisotropic Flows in 25 MeV/nucleon Ca + Ca by Quantum Molecular Dynamics Model

Anisotropic flows ($v_1$, $v_2$, $v_3$ and $v_4$) of light fragments up till the mass number 4 as a function of rapidity have been studied for 25 MeV/nucleon $^{40}$Ca + $^{40}$Ca at large impact parameters by Quantum Molecular Dynamics model. A phenomenological scaling behavior of rapidity dependent flow parameters $v_n$ (n = 1, 2, 3 and 4) has been found as a function of mass number plus a constant term, which may arise from the interplay of collective and random motions. In addition, $v_4/{v_2}^2$ keeps almost independent of rapidity and remains a rough constant of 1/2 for all light fragments.Comment: 4 pages, 5 figure

Method of determining cosmological parameter ranges with samples of candles with an intrinsic distribution

In this paper, the effect of the intrinsic distribution of cosmological candles is investigated. We find that, in the case of a narrow distribution, the deviation of the observed modulus of sources from the expected central value could be estimated within a ceratin range. We thus introduce a lower and upper limits of $\chi ^{2}$, $\chi_{\min}^{2}$ and $\chi_{\max}^{2}$, to estimate cosmological parameters by applying the conventional minimizing $\chi ^{2}$ method. We apply this method to a gamma-ray burst (GRB) sample as well as to a combined sample including this GRB sample and an SN Ia sample. Our analysis shows that: a) in the case of assuming an intrinsic distribution of candles of the GRB sample, the effect of the distribution is obvious and should not be neglected; b) taking into account this effect would lead to a poorer constraint of the cosmological parameter ranges. The analysis suggests that in the attempt of constraining the cosmological model with current GRB samples, the results tend to be worse than what previously thought if the mentioned intrinsic distribution does exist.Comment: 6 pages,4 figures,1 tables.Data updated. Main conclusion unchange

A general model for collaboration networks

In this paper, we propose a general model for collaboration networks. Depending on a single free parameter "{\bf preferential exponent}", this model interpolates between networks with a scale-free and an exponential degree distribution. The degree distribution in the present networks can be roughly classified into four patterns, all of which are observed in empirical data. And this model exhibits small-world effect, which means the corresponding networks are of very short average distance and highly large clustering coefficient. More interesting, we find a peak distribution of act-size from empirical data which has not been emphasized before of some collaboration networks. Our model can produce the peak act-size distribution naturally that agrees with the empirical data well.Comment: 10 pages, 10 figure

Macrovoids Formation and Light Scattering of PMMA

[[abstract]]After desorption of PMMA with saturated methanol and ethanol and then desorption by distilled water, the macrovoids are formed because of the phase inversion. The macrovoids on the surface of the specimens are larger and more numerous than those in the bulk. The macrovoids are likely to be closed-type, if the hydrolysis temperature is lower. On the other hand, if the hydrolysis temperature is higher, the macrovoids are likely to be open-type. Due to the formation of macrovoids, smaller than visible wavelengths, the light will disperse, and therefore, reduces the transmittance of the specimens. The transmittance is decreased when the hydrolysis temperature and hydrolysis time are increased. Furthermore, it is much clearer when ethanol is used as solvent than methanol. The scattered intensity of the specimens after hydrolysis is inversely proportional to the visible wavelength with an exponent, n, in the range 0·04–2·83 for methanol and 0·02–0·21 for ethanol[[incitationindex]]SCI[[booktype]]紙本[[booktype]]電子

The effects of degree correlations on network topologies and robustness

Complex networks have been applied to model numerous interactive nonlinear systems in the real world. Knowledge about network topology is crucial for understanding the function, performance and evolution of complex systems. In the last few years, many network metrics and models have been proposed to illuminate the network topology, dynamics and evolution. Since these network metrics and models derive from a wide range of studies, a systematic study is required to investigate the correlations between them. The present paper explores the effect of degree correlation on the other network metrics through studying an ensemble of graphs where the degree sequence (set of degrees) is fixed. We show that to some extent, the characteristic path length, clustering coefficient, modular extent and robustness of networks are directly influenced by the degree correlation.Comment: 13 pages, 6 figure

Alkaloids, Diarylheptanoid and Naphthalene Carboxylic Acid Ester from Rhoiptelea chiliantha

Two pyrrolidine alkaloids (1, 2) were isolated from the fruits of Rhoiptelea chiliantha DIEL et HAND.-MAZZ. (Rhoipteleaceae). A diphenyl ether-type diarylheptanoid (3), and a naphthalene carboxylic acid methyl ester (4) which is biogenetically-related to juglone were isolated from the branches of the same plant. Their chemical structures were elucidated on the basis of spectroscopic analysis and chemical evidence