268 research outputs found

    COMPUTATIONAL STUDY OF MOLECULAR STRUCTURES AND ANTIOXIDANT MECHANISM OF OVOTHIOLS

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    In this paper, the molecular structure and antioxidant activity of ovothiols (OSH) have beenstudied by using four DFT functionals, namely B3LYP, B3PW91, X3LYP, M06 with the basisset of 6-311++G(2df,2p). Two major antioxidant mechanisms, namely, hydrogen atom transfer(HAT) and stepwise electron transfer-proton transfer (SET-PT) have been investigated andapplied on three optimized conformations of ovothiols. Bond dissociation enthalpy (BDE),vertical ionization energy (IE), proton dissociation enthalpy (PDE), chemical potential (μ),chemical hardness (η) and global electrophilicity (ω), have been calculated and discussed in thegas phase

    RESEARCH ON PHYTOCHEMICAL AND ALFA-GLUCOSIDASE INHIBITORY ACTIVITY OF ETHYL ACETATE FRACTION OF RUELLIA TUBEROSA

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    ABSTRACT-HCTN75Rullia tuberosa L. is a folk remedy in the treatment of diabetes mellitus, anti inflammation and diuretic agent. However, its hypoglycemic activity has not been investigated so far. In the present study, the antidiabetic activity of the n-hexane, ethyl acetate and methanol fraction of crude ethanolic extract of this plant were investigated. Our preliminary results showed that the crude ethanol extract as well as ethyl acetate and methanol fractions of Ruellia tuberosa showed α-glucosidase inhibitory activity with IC50 of 15.84, 4.73 and 8.27 µg/ml, respectively. From the ethyl acetate extract of whole plant of Rullia tuberosa, four compounds, including rutin (1), syringaresinol (2), catechin (3) and pulmatin (4) were isolated and identified by column chromatography. Their structures were elucidated by spectroscopic method including MS, 1D and 2D- NMR and comparison with the literature values

    Solving POMDPs with Automatic Discovery of Subgoals

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    Numerical tools for the simulation of enzymatic bio porous-electrodes operating in DET mode

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    Modeling of diffusion/enzymatic reaction in porous electrodes operating in direct electron transfer mode is developed. The solution at the pore-scale is extremely cumbersome due to the complex geometry of the porous material. The upscaled model is much easier to solve, while keeping the essential of the physico-chemical behavior. The method to carry out the solution can be described as follows • The effective diffusion coefficient involved in the macroscopic equations is accurately computed by solving a closure problem in a representative elementary volume. • Electrochemical parameters are identified by a direct resolution of the macroscopic model solved with a COMSOL Multiphysics code coupled to a curve fit procedure carried out on voltammetry experimental results using a Matlab code. Electrodes with different thicknesses may be considered in the fitting procedure to improve accuracy. An alternative use of the COMSOL Multiphysics code is to predict the electrode behavior and further optimize its design, if all the electrochemical parameters are identified. • To validate the upscaled model, the pore scale model may be solved with direct numerical simulations carried out in a 3D microstructure using another COMSOL Multiphysics code to compare with the solution of the upscaled model in the 1D-reduced geometry.Modélisation d'électrodes poreuses pour leur conception optimisé

    Perceptions and practices of pesticides safety measures of rice farmers in the central region of Vietnam

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    The use of pesticides is increasing rapidly and the pesticide use crisis is badly damaging the environment, the economy, and public health in Vietnam. However, the country is yet to become successful in reducing pesticide use mostly because of policy implementation and inadequate understanding of farmers. This study examined and discussed the perceptions and safety level of using pesticides by applying a widely used index of 39 indicators equivalent to 39 safety measures grouped into four categories to assess the safety behaviour of rice farmers in the central region of Vietnam. A field survey of 320 rice farmers and 12 local leaders was conducted in Quang Tri and Thua Thien Hue provinces. The result revealed that there exists a significant difference (p0.001) between the perception and practices of pesticide safety measures of rice farmers in the study area. The overall score appears relatively high (4.09 and 3.89 out of 5.0 for perception and practices, respectively), indicating that farmers believe what they are doing is safe, though there are significant variations among the categories and among farmers in practicing pesticide safety measures. Regarding the farmers’ safety level, it was observed that there are still 18.1% and 34.4% of rice farmers are under unsafe and potentially unsafe conditions, respectively. Hence, an effective extension and communication program regarding the management and safety use of pesticides is the most vital policy solution to protect the rice farmers from potential health risks and ensure the sustainability of agriculture

    A new multiscale model for methane flow in shale gas reservoirs including adsorption in organic nanopores and on clay surfaces

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    A RESEARCH ON MULTI-OBJECTIVE OPTIMIZATION OF THE GRINDING PROCESS USING SEGMENTED GRINDING WHEEL BY TAGUCHI-DEAR METHOD

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    In this study, the mutil-objective optimization was applied for the surface grinding process of SAE420 steel. The aluminum oxide grinding wheels that were grooved by 15 grooves, 18 grooves, and 20 grooves were used in the experimental process. The Taguchi method was applied to design the experimental matrix. Four input parameters that were chosen for each experiment were the number of grooves in cylinder surface of grinding wheel, workpiece velocity, feed rate, and cutting depth. Four output parameters that were measured for each experimental were the machining surface roughness, the system vibrations in the three directions (X, Y, Z). The DEAR technique was applied to determine the values of the input parameters to obtaine the minimum values of machining surface roughness and vibrations in three directions. By using this technique, the optimum values of grinding wheel groove number, workpiece velocity, feed-rate, cutting depth were 18 grooves, 15 m/min, 2 mm/stroke, and 0.005 mm, respectively. The verified experimental was performed by using the optimum values of input parameters. The validation results of surface roughness and vibrations in X, Y, Z directions were 0.826 (µm), 0.531 (µm), 0.549 (µm), and 0. 646 (µm), respectively. These results were great improved in comparing to the normal experimental results. Taguchi method and DEAR technique can be applied to improve the quality of grinding surface and reduce the vibrations of the technology system to restrain the increasing of the cutting forces in the grinding process. Finally, the research direction was also proposed in this stud

    Towards Safer Operations: An Expert-involved Dataset of High-Pressure Gas Incidents for Preventing Future Failures

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    This paper introduces a new IncidentAI dataset for safety prevention. Different from prior corpora that usually contain a single task, our dataset comprises three tasks: named entity recognition, cause-effect extraction, and information retrieval. The dataset is annotated by domain experts who have at least six years of practical experience as high-pressure gas conservation managers. We validate the contribution of the dataset in the scenario of safety prevention. Preliminary results on the three tasks show that NLP techniques are beneficial for analyzing incident reports to prevent future failures. The dataset facilitates future research in NLP and incident management communities. The access to the dataset is also provided (the IncidentAI dataset is available at: https://github.com/Cinnamon/incident-ai-dataset).Comment: Accepted by EMNLP 2023 (The Industry Track
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