639 research outputs found

    Structures, Energies, and Bonding Analysis of Monoaurated Complexes with N-Heterocyclic Carbene and Analogues

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    In this work, we computationally investigated from quantum chemical calculations (DFT) at the BP86 level with the various basis sets def2-SVP, def2-TZVPP, and TZ2P+, chemical bonding issues of the recently described carbene-analogues gold(I) complexes AuCl-NHEMe (Au1-NHE) with E = C – Pb. The optimized structures and the metal-ligand bond dissociation energy (BDE) were calculated, and the nature of the E→Au bond was studied with charge and energy decomposition methods. The equilibrium structures of the system showed that there were major differences in the bonded orientation from the ligands NHC-NHPb to gold(I) complex between the lighter and the heavier homologues. The BDEs results showed that the metal-carbene analogues bonds were very strong bonds and the strongest bond was calculated for Au1-NHC which had the bond strength De = 79.2 kcal/mol. Bonding analysis of Au1-NHE showed that NHE ligands exhibited donor-acceptor bonds with the σ lone pair electrons of NHE donated into the vacant orbital of the acceptor fragment (AuCl). The EDA-NOCV results indicated that the ligand NHE in Au1-NHE complexes were strong σ-donors and very weak π donor and the bond order in complexes was Au1-NHC > Au1-NHSi > Au1-NHGe > Au1-NHSn > Au1-NHPb. We also realised that the gold-ligand bond was characterized by a π back-donation component from the Au to the ligand. All investigated complexes in this study were suitable targets for synthesis and gave a challenge in designing Au nano-crystals of narrow size distribution from gold(I) complexes that carried versatile N-heterocyclic carbene-analogues NHE

    The determinants of liquidity risk of commercial banks in Vietnam

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    This research identifies factors that explain the liquidity of commercial banks in the Vietnam banking system from 2010 to 2015. Using the OLS regression method for analysis, it was found that: the interbank market helps commercial banks improve their liquidity; the larger the loan size, the higher the liquidity risk; good credit risk management has a positive impact on liquidity risk management; and long-term interest rate is negatively related to the liquidity of commercial banks. The research also makes recommendations on liquidity risk management policies to banks and policy-makers from the Government and the State Bank of Vietnam

    Size-dependent decoherence of excitonic states in semiconductor microcrystallites

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    The size-dependent decoherence of the exciton states resulting from the spontaneous emission is investigated in a semiconductor spherical microcrystallite under condition aBR0λa_{B}\ll R_{0}\leq\lambda. In general, the larger size of the microcrystallite corresponds to the shorter coherence time. If the initial state is a superposition of two different excitonic coherent states, the coherence time depends on both the overlap of two excitonic coherent states and the size of the microcrystallite. When the system with fixed size is initially in the even or odd coherent states, the larger average number of the excitons corresponds to the faster decoherence. When the average number of the excitons is given, the bigger size of the microcrystallite corresponds to the faster decoherence. The decoherence of the exciton states for the materials GaAs and CdS is numerically studied by our theoretical analysis.Comment: 4 pages, two figure

    ADAPTABILITY OF VIETNAMESE SMEs TOWARD OUTSOURCING TREND

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    This article is to determine the adaptability of Vietnamese SMEs (small and toward international outsourcing trend. Organizations in developed countries usually find some less developed countries within which they may outsourceoperations. Outsourcing has become an effective good way for companies to increase profits by reducing production costs. This is attractive to less developed and developing countries as it encourages economic growth. However, to become an attractive destination of outsourcers, these developing countries need to possess high level human resources, attractive policies and business climate in conjunction with excellent infrastructure but low operation costs. Vietnamese SMEs only focus on labor-based outsourcing services which can bring about much lower benefits than aknowledge based services. A survey was done to get the viewpoints of Vietnamese SMEs’ managers about outsourcing requirements. After that we use the zero-sum method to determine which factors Vietnamese SMEs’ managers think the outsourcers should consider the most important when seeking outsource destination. Beside, we also base on background knowledge to understand Vietnamese SMEs’ entrepreneurship basing on this aspect. The result shows that Vietnamese SMEs think costs, especially labor costs, operation costs and administration costs are most important elements encourage outsourcers choose an outsourcing place

    Photoproduction of mesons in nuclei at GeV energies

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    In a transport model that combines initial state interactions of the photon with final state interactions of the produced particles we present a calculation of inclusive photoproduction of mesons in nuclei in the energy range from 1 to 7 GeV. We give predictions for the photoproduction cross sections of pions, etas, kaons, antikaons, and π+π\pi^+\pi^- invariant mass spectra in ^{12}C and ^{208}Pb. The effects of nuclear shadowing and final state interaction of the produced particles are discussed in detail.Comment: Text added in summary in general reliability of the method, references updated. Phys. Rev. C (2000) in pres

    Spatial assessment of pollutant loads for surface water quality management: a case study in Lai Chau city, Vietnam

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    The aim of this study is to present a method for estimating the pollutant load from different sources in an effort to provide improved information regarding water pollution and help control the surface water pollution, using Lai Chau city as a case study. The pollutant load was calculated in accordance with the Vietnam Environment Administration Decree No.154/2019 on the guidance for calculating the total pollutant load of river water. The pollutant sources include point sources (domestic wastewater, animal husbandry, industrial complexes and economic services) and surface sources (run-off from agricultural land uses) that generate wastes that potentially contaminate water bodies. The source locations were mapped and spatially joined with the drainage-basin map delineated from a Digital Elevation Model (DEM) to calculate the loads for the sub-basin units. Multivariate analysis then showed that the farming and domestic sources had the strongest positive loading factors for the sub-basins located in the city center and its fringe areas. Of these waste from animal husbandry account for up to 75.1% of total pollutant load. The main conclusion from the study's results is that the management approach should be changed from the total controlling mode, which is currently applied in the city, to a source specific approach based on the pollutant discharge loads and the allocated capacities

    Structural Evidence of Amyloid Fibril Formation in the Putative Aggregation Domain of TDP-43

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    TDP-43 can form pathological proteinaceous aggregates linked to ALS and FTLD. Within the putative aggregation domain, engineered repeats of residues 341-366 can recruit endogenous TDP-43 into aggregates inside cells; however, the nature of these aggregates is a debatable issue. Recently, we showed that a coil to β-hairpin transition in a short peptide corresponding to TDP-43 residues 341-357 enables oligomerization. Here we provide definitive structural evidence for amyloid formation upon extensive characterization of TDP-43(341-357) via chromophore and antibody binding, electron microscopy (EM), solid-state NMR, and X-ray diffraction. On the basis of these findings, structural models for TDP-43(341-357) oligomers were constructed, refined, verified, and analyzed using docking, molecular dynamics, and semiempirical quantum mechanics methods. Interestingly, TDP-43(341-357) β-hairpins assemble into a novel parallel β-turn configuration showing cross-β spine, cooperative H-bonding, and tight side-chain packing. These results expand the amyloid foldome and could guide the development of future therapeutics to prevent this structural conversion.Peer Reviewe

    Spin Transfer from a Ferromagnet into a Semiconductor through an Oxide barrier

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    We present results on the magnetoresistance of the system Ni/Al203/n-doped Si/Al2O3/Ni in fabricated nanostructures. The results at temperature of 14K reveal a 75% magnetoresistance that decreases in value up to approximately 30K where the effect disappears. We observe minimum resistance in the antiparallel configurations of the source and drain of Ni. As a possibility, it seems to indicate the existence of a magnetic state at the Si/oxide interface. The average spin diffusion length obtained is of 650 nm approximately. Results are compared to the window of resistances that seems to exist between the tunnel barrier resistance and two threshold resistances but the spin transfer seems to work in the range and outside the two thresholds
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