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Photogalvanic effect (PGE) occurs in materials with non-centrosymmetric structures when irradiated by linearly or circularly polarized light. Here, using non-equilibrium Green's function combined with density functional theory (NEGF-DFT), we investigated the linear photogalvanic effect (LPGE) in monolayers of group-V elements (As, Sb, and Bi) by first-principles calculations. First, by designing a two-probe structure based on the group-V elements, we found a giant anisotropy photoresponse of As between the armchair and zigzag directions. Then, we analyzed Sb and Bi's charge and spin photocurrent characteristics when considering the spin-orbit coupling (SOC) effect. It is found that when the polarization direction of linearly polarized light is parallel or perpendicular to the transport direction (θ = 0° or 90°), the spin up and spin down photoresponse in the armchair direction has the same magnitude and direction, leading to the generation of net charge current. However, in the zigzag direction, the spin up and spin down photoresponse have the same magnitude with opposite directions, leading to the generation of pure spin current. Furthermore, it is understood by analyzing the bulk spin photovoltaic (BSPV) coefficient from the symmetry point of view. Finally, we found that the net charge current generated in the armchair direction and the pure spin current generated in the zigzag direction can be further tuned with the increase of the material's buckling height ∣h∣. Our results highlight that these group-V monolayers are promising candidates for novel functional materials, which will provide a broad prospect for the realization of ultra-thin ferroelectric devices in optoelectronics due to their spontaneous polarization characteristics and high Curie temperature. [ABSTRACT FROM AUTHOR]

Background: Cancer-associated fibroblasts (CAFs), one of the main members of stromal cells in tumor microenvironment are proposed to play a central role in promoting tumor metastasis. It is unclear whether and how CAFs mediates tumor metastasis or chemoresistance in human ovarian cancer. Methods: CAFs were extracted from human ovarian cancer tissues (OCs) of patients with different kinds of histological types. Results: We found that CAFs showed more aggressive potency than those tumor cells, both of which were isolated from the same ovarian cancer specimen. Moreover, when co-cultured with CAFs, cell migration abilities of ovarian cancer cells (SKOV3, OVCAR3 and HEY) were significantly increased. Next, we preliminarily detected a higher CAFs density in sections of metastatic lesions than those in primary tumor site of primary OCs clinically. However, no significant difference of stromal derived factors-1α (SDF-1α) production from CAFs was found between primary and metastatic lesions. Additionally, in contrast with tumor cells, CAFs exhibited obvious apoptosis resistance when treated with cisplatin. Furthermore, we found that cisplatin-induced cytotoxicity and apoptosis were significantly inhibited by co-cultured with recombinant human SDF-1α in SKOV3 in a time and dose-dependent manner, and this effect was suppressed by the CXCR4 antagonist AMD3100. Conclusions: CAFs might be involved in the malignant metastasis in human ovarian cancer through promoting cell migration in tumor cells. And their resistance to cytotoxic agents might be mediated by paracrine SDF-1α/CXCR4 signaling in ovarian cancer. [ABSTRACT FROM AUTHOR]

By simulating nonequilibrium processes like biological transport, traffic transport, etc., totally asymmetric simple exclusion process (i.e., TASEP) is vital to understand stochastic dynamics of lattice systems. Stochastic networks using TASEP as underlying dynamics make a more practical generalization of traditional exclusion models, which better simulate real transport processes. According to real experimental data, a new network structure of nonaverage weight assignment at nodes is constructed to further understand physical mechanisms of molecular motors transporting along microtubules. Two typical kinesins, KIF3AC and KIF3CC, are used as modeling bases. High-tendency segments and low-tendency segments are introduced to characterize heterogeneous flow distribution at nodes. Multi-body system dynamics affected by the global density are studied. Edge densities are analyzed by using new mean-field theories compared with Monte Carlo simulations. New detailed structures of adsorption and desorption at nodes are considered. In order to restore a motor transport framework more suitable for real systems, analytical solutions and simulations of local statistical densities and phase diagrams affected by particle desorption and no desorption are obtained. This work provides help for understanding dynamical mechanisms of complex networks and other important nonlinear physics depicting molecular motors transport, cytoskeleton designs, structural optimizations, etc. [ABSTRACT FROM AUTHOR]

The molten salt electrochemical method is an efficient one-step process to extract tungsten from tungsten carbide (WC). Owing to the limitation of molten salt electrochemical experiments and the number of data points, determining the optimal process conditions is challenging. In addition, the mechanism that affects the current efficiency is difficult to obtain intuitively. In this study, simulations of tungsten carbide anode electrolysis were obtained using the COMSOL Multiphysics 5.3, and the results were compared to the dissolution experiment of tungsten carbide with varying content of sodium tungstate (Fig. 1). The experimental data fitted well with the theoretical current efficiency of 75%. At concentrations below 0.5 wt% of sodium tungstate, the anode dissolution showed a linear relationship against the concentration of sodium tungstate. At a constant concentration of sodium tungstate, the anodic dissolution decreased with increasing immersion depth, consistent with the variation of cell voltage difference before and after electrolysis. The optimal immersion depth and effective area of the anode estimated by simulations were 2.5 mm and 0.465 mm2, respectively (Fig. 2). Under the optimum electrolysis conditions simulated by COMSOL, the nano tungsten powder was obtained. [ABSTRACT FROM AUTHOR]

Molten salt is an excellent medium for chemical reaction, energy transfer, and storage. Molten salt innovative technologies should be developed to recover metals from secondary resources and reserve metals from primary natural sources. Among these technologies, molten salt electrolysis is an economic and environment-friendly method to extract metals from waste materials. From the perspective of molten salt characteristics, the application of molten salts in chemistry, electrochemistry, energy, and thermal storage should be comprehensively elaborated. This review discusses further directions for the research and development of molten salt electrolysis and their use for metal recovery from various metal wastes, such as magnet scrap, nuclear waste, and cemented carbide scrap. Attention is placed on the development of various electrolysis methods for different metal containing wastes, overcoming some problems in electrolytes, electrodes, and electrolytic cells. Special focus is given to future development directions for current associated processing obstacles. [ABSTRACT FROM AUTHOR]

We consider estimating multiple structural changes occurring at unknown common dates in a panel data regression model with restrictions imposed on the coefficients. We establish the consistency and rate of convergence of the structural change estimates and the asymptotic distribution of the parameter estimates. It is shown that the efficiency of the parameter estimators is increased using the restrictions. An efficient dynamic algorithm is proposed to obtain the break date estimates and the parameter estimates. In addition, we propose a testing procedure for the existence of the change points with the restrictions and derive the asymptotic distribution under the null hypothesis of the test statistics. Simulation studies are presented to investigate the performance of the proposed method in finite samples. [ABSTRACT FROM AUTHOR]

The discovery of antibiotics from microorganisms using classic bioactivity screens suffers from heavy labor and high re-discovery rate. Recently, largely uncovered biosynthetic potentials were unveiled by new approaches, such as genetic manipulation of “silent” biosynthetic gene clusters, innovative data acquisition, and processing methods. In this work, a fast and efficient antibiotic identification pipeline based on the MALDI-TOF imaging mass spectrometry was applied to study the antifungal metabolites during the confrontation of two fungal species, Penicillium polonicum and wilt-inducing fungus Fusarium oxysporum. By visualizing the spatial distribution of metabolites directly on the microbial colony and surrounding media, we predicted the antifungal candidates before isolating pure compounds and individually testing their bioactivity, which subsequently guided the identification of target molecules using classic chromatographic methods. Via this procedure, we successfully identified two antifungal metabolites, fructigenine A and B, which belong to indole alkaloid class and were not reported for antifungal activity. Our work assigned new bioactivity to previously reported compounds and more importantly showed the efficiency of this approach towards quick discovery of bioactive compounds, which can help study the vast unexploited synthetic potential of microbial secondary metabolites. [ABSTRACT FROM AUTHOR]

There have been several epidemiological studies evaluating the potential association between the methylenetetrahydrofolate reductase (MTHFR) A1298C polymorphism and the risk of male infertility. However, the results obtained were inconsistent. Therefore, we performed a meta-analysis to further examine the association between the MTHFR A1298C polymorphism and male infertility. A comprehensive search was conducted to identify all eligible studies from the online literature databases published prior to January 15th, 2016. A total of 20 studies with 4293 cases and 4507 controls were included. An odds ratio (OR) and a 95% confidence interval (95% CI) were calculated to assess the strength of the association. A cumulative meta-analysis, sensitivity analysis and assessment of the publication bias were also performed in this study. The results showed that in the overall analysis, the association between the MTHFR A1298C polymorphism and male infertility was not significant. A stratified analysis by ethnicity revealed a significant increase in the risk of male infertility in the Asian population with the MTHFR A1298C polymorphism (especially in the heterozygote model: OR=1.20, 95% CI=1.01-1.44, P=0.994; the dominant model: OR=1.23, 95% CI=1.04-1.45, P=0.996; and the allele model: OR=1.20, 95% CI=1.04-1.39, P=0.985) but not in the Caucasian population. In the stratified analyses, no significant association was observed between the different types of male infertility. This meta-analysis suggests the MTHFR A1298C polymorphism may be a potential risk factor for male infertility, especially in the Asian population. [ABSTRACT FROM AUTHOR]

The metadynamic recrystallization (MDRX) behavior of a Nb–V microalloyed nonquenched and tempered steel was investigated by isothermal hot compression tests on Gleeble-1500 thermal-mechanical simulator. Compression tests were performed using double hit schedules at temperatures of 1273–1423 K, strain rates of 0.01–5 s−1, initial grain sizes of 92–149 μm and an inter-pass time of 0.5–10 s. The experimental results show that MDRX softening fraction increases with the increasing of deformation temperature, strain rate, and inter-pass time, while it decreases with the increasing of initial grain size. Based on the experimental results, the MDRX softening fraction kinetic model and recrystallized grain size model of the tested steel was established. Besides, using the above mathematic models, a finite element model was built to simulate the MDRX process of the tested steel. The simulation results show good agreement with the experimental ones, which indicates that finite element method is an effective approach to analyze the MDRX behavior and the established that mathematic models of the tested steel are reliable and accurate. [ABSTRACT FROM PUBLISHER]

The dynamic recrystallization (DRX) and flow behavior of a medium carbon Nb-V microalloyed steel was investigated using hot isothermal compression experiments in a wide range of temperatures (1123-1473 K) and strain rates (0.01-10 s). The flow stress curves were analyzed comprehensively, and it was found that the flow stress of this steel is higher than C-Mn steel and V microalloyed steel. All the curves obtained can be ranged into three principal types: work hardening, dynamic recovery, and DRX. The DRX behavior of this steel was investigated, including critical strain, kinetics of DRX, and microstructure. The constitutive equation to predict the flow stress of the tested steel was also developed, and the analysis result indicates that the developed model has a high accuracy in predicting the flow stress during hot deformation. [ABSTRACT FROM AUTHOR]

In this paper we provide a method to test the existence of the change points in the nonparametric regression function of partially linear models with conditional heteroscedastic variance. We propose the test statistic and establish its asymptotic properties under some regular conditions. Some simulation studies are given to investigate the performance of the proposed method in finite samples. Finally, the proposed method is applied to a real data for illustration. [ABSTRACT FROM AUTHOR]

A stress relaxation test has been carried out for Hastelloy C-276 at temperature of 800 °C and initial stress level of 250 MPa. Based on the experimental stress relaxation curve, the relationship between creep strain rate and stress has been derived. Then, a set of creep constitutive equations has been built and the values of constants arising in the constitutive equations have been determined by fitting the creep strain rate-stress curve. Close agreement between computed results and experimental ones is obtained for stress relaxation data. The creep constitutive equation set has been integrated with the commercial FE (finite element) solver MSC. Marc via the user defined subroutine, CRPLAW, for the vacuum hot bulge forming process modelling of Hastelloy C-276 thin-walled cylindrical workpiece. The temperature field, the radius-direction displacement field and the stress-strain field are calculated and analyzed. Furthermore, the bulging dimension and the final internal diameter of workpiece are predicted and the test results verify the reliability of the finite element method. [ABSTRACT FROM AUTHOR]

The dynamic recrystallization behavior of 38MnVS6 non-quenched steel was investigated by hot compression tests on a Gleeble1500 thermomechanical simulator. True stress-strain curves and deformed specimens were obtained in the temperature range of 850-1200 °C and the strain rate range of 0.01-10 s. By regression analysis of the experimental results, the critical strain model and austenite grain size model for dynamic recrystallization were established as a function of Zener-Hollomon parameter. The dynamic recrystallization kinetic model for 38MnVS6 non-quenched steel was established on the basis of the modified Avrami equation. In addition, based on the dynamic material model, the processing map of the steel was established at the strain of 0.5. It was found that the unstable phenomena of the steel did not appear at the deformation conditions. The processing map exhibited a domain of complete dynamic recrystallization occurring in the temperature range of 950-1200 °C and the strain rate range of 0.01-5 s, which were the optimum parameters for the hot working of the steel. [ABSTRACT FROM AUTHOR]

The accumulation of thermal time usually represents the local heat resources to drive crop growth. Maps of temperature-based agro-meteorological indices are commonly generated by the spatial interpolation of data collected from meteorological stations with coarse geographic continuity. To solve the critical problems of estimating air temperature ( T) and filling in missing pixels due to cloudy and low-quality images in growing degree days (GDDs) calculation from remotely sensed data, a novel spatio-temporal algorithm for T estimation from Terra and Aqua moderate resolution imaging spectroradiometer (MODIS) data was proposed. This is a preliminary study to calculate heat accumulation, expressed in accumulative growing degree days (AGDDs) above 10 °C, from reconstructed T based on MODIS land surface temperature (LST) data. The verification results of maximum T, minimum T, GDD, and AGDD from MODIS-derived data to meteorological calculation were all satisfied with high correlations over 0.01 significant levels. Overall, MODIS-derived AGDD was slightly underestimated with almost 10% relative error. However, the feasibility of employing AGDD anomaly maps to characterize the 2001-2010 spatio-temporal variability of heat accumulation and estimating the 2011 heat accumulation distribution using only MODIS data was finally demonstrated in the current paper. Our study may supply a novel way to calculate AGDD in heat-related study concerning crop growth monitoring, agricultural climatic regionalization, and agro-meteorological disaster detection at the regional scale. [ABSTRACT FROM AUTHOR]

We aimed to develop liposomes for loading both cisplatin and quantum dots (QDs) for both drug delivery and bioimaging. The resultant quantum-dot-liposomes (QDLs) with cisplatin were characterized using dynamic light scattering, transmission electron microscopy (TEM), encapsulation efficiencies, and fluorescence intensity. QDLs composed of CdSe or CdSe/ZnS QDs represented a size of about 100 nm. The QDLs were prepared at a high QD loading efficiency of nearly 100 %. Most QDs were located within the liposomal bilayers as evidenced by TEM. Slow and sustained cisplatin release from QDLs was achieved. The cellular uptake of QDLs demonstrated effective internalization and significant fluorescence in melanoma cells. The signal derived from QDLs could be observed by different wavelength settings. The cisplatin-containing QDLs revealed higher cytotoxic activity compared to an equal dose of free cisplatin. CdSe/ZnS QDLs were intravenously administered to mice, and the biodistribution was observed with an in vivo imaging system. Significant fluorescence signal and cisplatin accumulation were detected in the brain and skin, as verified by ex vivo imaging and drug distribution. Liposomal inclusion could reduce the reticuloendothelial system uptake of QDs and cisplatin. QDLs evaluated in this study represent a new potential method for theranostic purposes. [ABSTRACT FROM AUTHOR]

This paper discusses the application of several techniques involved in the development of the 3D finite element (FE) models of rod and wire continuous rolling process. The FE models are implemented into the FE-program MSC.Marc and used to investigate the thermal and mechanical behavior of billet during the rolling process. All nonlinear equations included in the models are solved by the static and dynamic procedures, respectively. Data transfer technique is proposed to keep the continuity of simulation results. And the computational time of static procedure is significantly reduced by using a rigid pushing body. In all models, the constant time step method and the auto time step method are respectively used to define time step for the solution of equations. Simulation results of the models with different time step methods are compared. And comparison between calculated values and measured ones of the temperature at the surface of billet shows the validity of the FE models. [ABSTRACT FROM AUTHOR]

Bee venom phospholipase A2 (BvPLA2) is a lipolytic enzyme that catalyzes the hydrolysis of the sn-2 acyl bond of glycerophospholipids to liberate free fatty acids and lysophospholipids. In this work, a new BvPLA2 (AccPLA2) gene from the Chinese honeybee ( Apis cerana cerana) venom glands was inserted into bacmid to construct a recombinant transfer vector. Tn-5B-4 (Tn) cells were transfected with the recombinant bacmid DNA for expression. Sodium dodecylsulfate-polyacrylamide gel electrophoresis (SDS-PAGE) analysis revealed a double band with molecular weights of 16 and 18 kDa. Products of hexahistidine AccPLA2 fusion protein accumulated up to 5.32% of the total cellular proteins. The AccPLA2 fusion protein was cross reactive with the anti-AmPLA2 (BvPLA2 of the European honeybee, Apis mellifera) polyclonal serum. The reaction resulted in a double glycosylation band, which agrees with the band generated by the native AmPLA2 in Western blot analysis. The PLA2 activity of the total extracted cellular protein in the hydrolyzing egg yolk is about 3.16 μmol/(min·mg). In summary, the recombinant AccPLA2 protein, a native BvPLA2-like structure with corresponding biological activities, can be glycosylated in Tn cells. These findings provided fundamental knowledge for potential genetic engineering to produce AccPLA2 in the pharmaceutical industry. [ABSTRACT FROM AUTHOR]

Detection of crop health conditions plays an important role in making control strategies of crop disease and insect damage and gaining high-quality production at late growth stages. In this study, hyperspectral reflectance of rice panicles was measured at the visible and near-infrared regions. The panicles were divided into three groups according to health conditions: healthy panicles, empty panicles caused by Nilaparvata lugens St&Oal, and panicles infected with Ustilaginoidea virens. Low order derivative spectra, namely, the first and second orders, were obtained using different techniques. Principal component analysis (PCA) was performed to obtain the principal component spectra (PCS) of the foregoing derivative and raw spectra to reduce the reflectance spectral dimension. Support vector classification (SVC) was employed to discriminate the healthy, empty, and infected panicles, with the front three PCS as the independent variables. The overall accuracy and kappa coefficient were used to assess the classification accuracy of SVC. The overall accuracies of SVC with PCS derived from the raw, first, and second reflectance spectra for the testing dataset were 96.55%, 99.14%, and 96.55%, and the kappa coefficients were 94.81%, 98.71%, and 94.82%, respectively. Our results demonstrated that it is feasible to use visible and near-infrared spectroscopy to discriminate health conditions of rice panicles. [ABSTRACT FROM AUTHOR]

The hot deformation behaviors of GCr15 bearing steel were investigated by isothermal compression tests, performed on a Gleeble-3800 thermal-mechanical simulator at temperatures between 950 °C and 1 150 °C and strain rates between 0.1 and 10 s−1. The peak stress and peak strain as functions of processing parameters were obtained. The dependence of peak stress on strain rate and temperature obeys a hyperbolic sine equation with a Zener-Hollomon parameter. By regression analysis, in the temperature range of 950−1 150 °C and strain rate range of 0.1−10 s−1, the mean activation energy and the stress exponent were determined to be 351 kJ/mol and 4.728, respectively. Meanwhile, models of flow stress and dynamic recrystallization (DRX) grain size were also established. The model predictions show good agreement with experimental results. [ABSTRACT FROM AUTHOR]

The article offers information on secondary metabolites of endophytic fungi from Huperzia serrata. Topics discussed include collection of specimen for fungi to analyze metabolites of Huperzia, extraction of curvulinic acid, O-methylcurvulinic acid, methyl curvulinate and fuscoatramide from Huperzia, and physical and chemical information on various metabolites.