First Principles Study on the Electronic Structure and Interface Stability of Hybrid Silicene/Fluorosilicene Nanoribbons

© 2015 Macmillan Publishers Limited. The interface stability of hybrid silicene/fluorosilicene nanoribbons (SFNRs) has been investigated by using density functional theory calculations, where fluorosilicene is the fully fluorinated silicene. It is found that the diffusion of F atoms at the zigzag and armchair interfaces of SFNRs is endothermic, and the corresponding minimum energy barriers are respectively 1.66 and 1.56 eV, which are remarkably higher than the minimum diffusion energy barrier of one F atom and two F atoms on pristine silicene 1.00 and 1.29 eV, respectively. Therefore, the thermal stability of SFNRs can be significantly enhanced by increasing the F diffusion barriers through silicene/fluorosilicene interface engineering. In addition, the electronic and magnetic properties of SFNRs are also investigated. It is found that the armchair SFNRs are nonmagnetic semiconductors, and the band gap of armchair SFNRs presents oscillatory behavior when the width of silicene part changing. For the zigzag SFNRs, the antiferromagnetic semiconducting state is the most stable one. This work provides fundamental insights for the applications of SFNRs in electronic devices

In situ loading and delivery of short single- And double-stranded dna by supramolecular organic frameworks

Short DNA represents an important class of biomacromolecules that are widely applied in gene therapy, editing, and modulation. However, the development of simple and reliable methods for their intracellular delivery remains a challenge. Herein, we describe that seven water-soluble, homogeneous supramolecular organic frameworks (SOFs) with a well-defined pore size and high stability in water that can accomplish in situ inclusion of single-stranded (ss) and double-stranded (ds) DNA (21, 23, and 58 nt) and effective intracellular delivery (including two noncancerous and six cancerous cell lines). Fluorescence quenching experiments for single and double endlabeled ss- and ds-DNA support that the DNA sequences can be completely enveloped by the SOFs. Confocal laser scanning microscopy and flow cytometry reveal that five of the SOFs exhibit excellent delivery efficiencies that, in most of the studied cases, outperform the commercial standard Lipo2000, even at low SOF-nucleic acid ratios. In addition to high delivery efficiencies, the watersoluble, self-assembled SOF carriers have a variety of advantages, including convenient preparation, high stability, and in situ DNA inclusion, which are all critical for practical applications in nucleic acid delivery

Density functional theory study on the electronic properties and stability of silicene/silicane nanoribbons

© The Royal Society of Chemistry 2015. The thermal stability of silicene/silicane nanoribbons (SSNRs) has been investigated by using density functional theory calculations, where silicane is the fully hydrogenated silicene. It was found that the minimum energy barriers for the diffusion of hydrogen atoms at the zigzag and armchair interfaces of SSNRs are 1.54 and 1.47 eV, respectively, while the diffusion of H atoms at both interfaces is always endothermic. Meanwhile, the minimum diffusion energy barriers of one H atom and two H atoms on pristine silicene are 0.73 and 0.87 eV, respectively. Therefore, the thermal stability of SSNRs can be significantly enhanced by increasing the hydrogen diffusion barriers through silicene/silicane interface engineering. In addition, the zigzag SSNR remains metallic, whereas the armchair SSNR is semiconducting. However, the silicene nanoribbons part-determine the metallic or semiconducting behaviour in the SSNRs. This work provides fundamental insights for the applications of SSNRs in electronic devices. This journal i

p38 Mapk signal pathway involved in anti-inflammatory effect of chaihu-shugan-san and shen-ling-bai-zhu-san on hepatocyte in non-alcoholic steatohepatitis rats

Background: Traditional Chinese Medicine (TCM), has over thousands-of-years history of use. Chaihu-Shugan-San (CSS), and Shen-ling-bai-zhu-San (SLBZS), are famous traditional Chinese herbal medicine formulas, which have been used in China, for the treatment of many chronic diseases.Materials and Methods:This study investigated the anti-inflammatory effects of CSS and SLBZS on signaling molecules involved in p38 mitogen-activated protein kinase (p38 MAPK), pathway on hepatocytes of non-alcoholic steatohepatitis (NASH), rats induced by high fat diet. SD male rats were randomly divided into 8 groups: negative control group, model control group, high (9.6g/kg/day)/low (3.2g/kg/day)-dose CSS group, high (30g/kg/day)/low (10g/kg/day)-dose SLBZS group, high (39.6g/kg/day)/low (13.2g/kg/day)-dose integrated group. The rats of NASH model were induced by feeding a high-fat diet. After 16, wks, Hepatocytes were isolated from 6, rats in each group by collagenase perfusion. The liver histopathological changes and serum inflammatory cytokines TNF-α, IL-6 were determined. The proteins of TLR4,  phosphor-p38 MAPK and p38 MAPK involved in p38 MAPK signal pathway were assayed.Results: The statistical data indicated the NASH model rats reproduced typical histopathological features of NASH in human. CSS and SLBZS ameliorated lipid metabolic disturbance, attenuated NASH progression, decreased the levels of TNF-α and IL-6 in serum, as well as inhibited TLR4 protein expression, p38 MAPK phosphorylation, and activation of p38 MAPK. In conclusion, CSS and SLBZS might work as a significant anti-inflammatory effect on hepatocyte of NASH by inhibiting the activation of TLR4, p-p38 MAPK and p38 MAPK involved in p38 MAPK signal pathway.Conclusion: To some extent, CSS and SLBZS may be a potential alternative and complementary medicine to protect against liver injury, alleviate the inflammation reaction, moderate NASH progression.Key words: p38 mitogen-activated protein kinase; Toll like receptor 4; Hepatocytes; Non-alcoholic Steatohepatitis; Traditional Chinese medicine

Quantifying the effects of elevated CO<inf>2</inf> on water budgets by combining FACE data with an ecohydrological model

© 2014 John Wiley & Sons, Ltd. Response of leaf area index (LAI) is the key determinant for predicting impacts of the elevated CO 2 (eCO 2 ) on water budgets. Importance of the changes in functional attributes of vegetation associated with eCO 2 for predicting responses of LAI has rarely been addressed. In this study, the WAter Vegetation Energy and Solute (WAVES) model was applied to simulate ecohydrological effects of the eCO 2 at two free-air CO 2 enrichment (FACE) experimental sites with contrasting vegetation. One was carried out by the Oak Ridge National Laboratory on the forest (ORNL FACE). The other one was conducted by the University of Minnesota on the grass (BioCON FACE). Results demonstrated that changes in functional attributes of vegetation (including reduction in specific leaf area, changes in carbon assimilation and allocation characteristics) and availability of nutrients are important for reproducing the responses of LAI, transpiration and soil moisture at both sites. Predicted LAI increased slightly at both sites because of fertilization effects of the eCO 2 . Simulated transpiration decreased 10·5% at ORNL site and 13·8% at BioCON site because of reduction in the stomatal conductance. Predicted evaporation from interception and soil surface increased slightly ( < 1·0mmyear -1 ) at both sites because of increased LAI and litter production, and increased soil moisture resulted from reduced transpiration. All components of run-off were predicted to increase because of significant decrease in transpiration. Simulated mean annual evapotranspiration decreased about 8·7% and 10·8%, and mean annual run-off increased about 11·1% (59·3mmyear -1 ) and 9·5% (37·6mmyear -1 ) at the ORNL and BioCON FACE sites, respectively

Multi-variable thermal modeling of power devices considering mutual coupling

© 2019 by the authors. In relation to power converter design, power density is increasing while the form factor is decreasing. This trend generally reduces the rate of the cooling process, which increases the mutual thermal coupling among the surrounding power components. Most of the traditional models usually ignore the mutual effects or just focus on the conduction coupling. To deal with these factors, the thermal modeling for a boost converter system has been built to compare the junction temperatures (Tj) and the increments under different working conditions in order to consider the conduction coupling. A multi-variable thermal resistances model is proposed in this paper to incorporate the convection thermal coupling into the mutual thermal effects. The coupling resistances, MOSFET to the diode (Rcp-DM ⇀), and the diode to MOSFET (Rcp-DM ⇀) have been calculated and the relationships between coupling resistances and their impact factors (separation distances and working currents) have been discussed. New case temperatures (Tc) obtained by calculation and additional measurements at other separation distances serve to verify the efficacy of the proposed model. This model enhances the current thermal models and provides an effective method to calculate the thermal coupling resistances which can be used to estimate the Tj. As the coupling resistances are distance dependent, the model also helps to optimize and fine-tune the placements of components in high-power density converters

Impacts of elevated CO<inf>2</inf>, climate change and their interactions on water budgets in four different catchments in Australia

© 2014 Elsevier B.V. Future water availability is affected directly by climate change mainly through changes in precipitation and indirectly by the biological effects of climate change and elevated atmospheric CO2 concentration (eCO2) through changes in vegetation water use. Previous studies of climate change impact on hydrology have focused on the direct impact and little has been reported in the literature on catchment-scale the indirect impact. In this study, we calibrated an ecohydrological model (WAVES) and used this model to estimate the direct and indirect effects and the interactive effect between climate change and eCO2 on water availability in four different catchments in Australia with contrasting climate regime and vegetation cover. These catchments were: a water-limited forest catchment and an energy-limited forest catchment, a water-limited grass catchment and an energy-limited grass catchment. The future meteorological forcing was projected from 12 GCMs representing a period centred on 2050s and future CO2 concentration was set as 550ppm. Modelling experiments show that impacts of eCO2 and projected climate change on vegetation growth, evapotranspiration (ET) and runoff were in the same magnitude but opposite directions in all four catchments, except for the effects on runoff in the energy-limited grass catchment. Predicted responses of runoff to eCO2 indicate that eCO2 increased runoff in the energy-limited forest catchment by ~2% but decreased runoff in other three catchments from 1% to 18%. This study indicates that rising CO2 increases ecosystem water use efficiency but it does not necessarily result in increased runoff because elevated CO2 also stimulates vegetation growth and increases ET. Elevated CO2 was proved to have greater impacts on runoff than climate change in the forest catchments. Modelling experiments also suggest that interactive effects between climate and CO2 are important, especially for predicting leaf area index (LAI) and ET in grassland catchments or runoff in water-limited catchments, where interactive effects were 1-6%. It implies that the assumption that linear combination of individual effects in most of previous studies is not appropriate. This study highlights the importance of considering elevated CO2 in assessing climate change impacts on catchment-scale water balance and failure to account for direct eCO2 effect or its interactive effects can lead to large bias in the predictions of future water budgets, especially for the water-limited catchments in Australia

Experimental study of subcooled flow boiling heat transfer on micro-pin-finned surfaces in short-term microgravity

The flow boiling heat transfer of subcooled air-dissolved FC-72 on micro-pin-finned surfaces was studied in microgravity by utilizing the drop tower facility in Beijing. The micro-pin-fins with the dimension of 30 x 30 x 60 mu m(3) (width x thickness x height), named PF30-60, were fabricated on a silicon chip by using the dry etching technique. For comparison, experiments of flow boiling heat transfer in terrestrial gravity were also conducted. The effects of inlet velocity on both flow boiling heat transfer and bubble behavior were explored. It was found that gravity has nearly no effect on flow boiling heat transfer for the departure of the inertial-force dominant bubbles in the low and moderate heat fluxes regions. In contrast, in the high-heat-flux region, the flow boiling heat transfer deteriorates and the critical heat flux (CHF) decreases due to the bubble accumulation in the channel. For PF30-60 at V = 0.5 m/s, the CHF point can be inferred to be between 20.8 and 24.5 W/cm(2), which is 63.0-74.2% of that in normal gravity. Regarding PF30-60 at V = 1.0 m/s, the CHF point can be inferred to be between 25.4 and 31.6 W/cm(2), which is 67.6-84.0% of that in normal gravity. The impact of gravity on CHF is closely linked to the channel geometry parameter and surface modification. The dimensionless numbers, Ch (Channel number) and Sf (Surface number), were proposed to describe the effect of the channel geometry and surface modification on the ratio of CHF in microgravity to that in normal gravity (CHF mu g/CHF1g). An empirical correlation based on We (Weber number), Ch and Sf was proposed to predict the value of CHF mu g/CHF1g ratio in good agreement with the experimental data. This study provides a new perspective to determine the threshold inlet velocity of inertial-force-dominant flow boiling under different experimental conditions at different gravity levels

Ethnic differences in susceptibilities to A(H1N1) flu: An epidemic parameter indicating a weak viral virulence

The current A(H1N1) flu has showed sub-population dependent susceptibility and fatality as early as April and May of 2009 in its first wave of spreading. After the pandemic outbreak spreads globally for more than seven months, the subpopulation dependence of this flu, including ethnicity, age and genderselectivity, has been recognized by several research groups. This paper attempts to discussed how to identify ethnic selectivity from the released data by WHO relevant to this ongoing flu, review some recently published papers describing the presence of ethnic differences in susceptibilities to the H1N1flu virus and further raised an argument that ethnic differences in&#160; susceptibilities to a virus might be a piece of evidence reflecting a weak virulence of that specific virus

Protective effect of wild Corni fructus methanolic extract against acute alcoholic liver injury in mice

Background: In Chinese folk medicine, Corni fructus (C. fructus) has traditionally been used to improve liver function, although the mechanism underlying its activity remains unclear. The aim of the present study was to evaluate the protective effects of wild C. fructus methanolic extract against acute alcoholic liver injury.Methods: Alcohol was administered to mice for three consecutive days, either alone or in combination with C. fructus methanolic extract (50, 100, or 200mg/kg body weight/d). Serum and liver tissue were collected from the animals and subjected to biochemical and histopathological analyses.Results:C. fructus significantly alleviated alcohol-induced liver injury by reducing serum alanine aminotransferase, aspartate aminotransferase, and thiobarbituric acid reactive species, inhibiting hydroxyl radicals (center dot OH), and increasing total superoxide dismutase, glutathione peroxidase, and glutathione in the liver (P<0.05). In addition, the C. fructus treatment inhibited the expression and activity of cytochrome P450 2E1 (P<0.05)Conclusions:C. fructus could be a promising natural substance for ameliorating acute alcohol-induced oxidative stress and hepatic injury.- This work was supported by the Construction Project of Shaanxi Collaborative Innovation Center (2015, Shaanxi Sci-tech University); High-End Foreign Experts Recruitment Program [Grant GDW20146100228]; and Key Construction Program of International Cooperation Base in S&T Shaanxi Province, China [Grant 2015SD0018].info:eu-repo/semantics/publishedVersio