DSpace Collection: Vietnam Academy of Science and Technology
https://dspace.ctu.edu.vn/jspui/handle/123456789/2023
Vietnam Academy of Science and Technology2024-03-28T14:26:05ZUnderstanding the adsorptive interactions of carbon dioxide with metal-organic framework (IRMOF-1) using a theoretical approach
https://dspace.ctu.edu.vn/jspui/handle/123456789/97836
Title: Understanding the adsorptive interactions of carbon dioxide with metal-organic framework (IRMOF-1) using a theoretical approach
Authors: Ha, Thi Thao; Phung, Thi Lan; Nguyen, Dinh Thoai; Tran, Thanh Hue; Nguyen, Ngoc Ha; Nguyen, Thi Thu Ha
Abstract: Density Functionalbased Tight-binding method with dispersion corrections and Molecular Dynamics (MD) simulations were performed to study the carbon dioxide (CO2) adsorption process on a metal-organic framework (IRMOF-1). The adsorption centers, adsorption energy, adsorption capacity, diffusion coefficient, and the effect of temperature on the adsorption process have been thoroughly examined and elucidated. The calculated results reveal that the favorable CO2 adsorption site on IRMOF-1 is the position where the CO2 molecule is located in the cavity formed by themetalclusterand oxygenatoms of the three-COO groups of the organicligand. The CO2 moleculeswereinstantly adsorbed on the IRMOF-1structure as "anchors" to hold the next molecules in place. The Monte Carlo simulation results demonstrate that when the concentration of CO2 molecules is low, they preferentially adsorb onto the surface of IRMOF-1. As the number of CO2 molecules increases, they will gradually occupy the free space inside the crystal. The MD simulations with constant volume and temperature have shown that up to 350K, CO2 was still dynamically adsorbed on IRMOF-1, without being desorbed.The calculated diffusion coefficients implythat CO2 would diffuse into IRMOF-1 slower thanmethane, but quicker than oxygen and nitrogen. Therefore, it is feasible to separate CO2 from itsmixturewith oxygen and nitrogen using IRMOF-1.2022-01-01T00:00:00ZMethodological aspects for the study of nucleation and growth mechanisms of metals from deep eutectic solvents based on choline chloride
https://dspace.ctu.edu.vn/jspui/handle/123456789/97649
Title: Methodological aspects for the study of nucleation and growth mechanisms of metals from deep eutectic solvents based on choline chloride
Authors: Dao, Vu Phuong Thao; Pham, Thi Lanh; Chu, Thi Xuan; Nguyen, Van Hieu; Le, Manh Tu
Abstract: This paper presents a methodology for studying nucleation and growth mechanisms of metals onto a glassy carbon electrode in a deep eutectic solvent (DES), a mixture of choline chloride and urea at a molar ratio of 1:2. Characteristics and composition of Co(II) complexes formed with the DES were evaluated by means of UV-vis measurements, which confirmed the good stability of these species at room temperature. To elucidate the methodology, kinetic and mechanistic aspects of the early stage of cobalt electrodeposition were studied using cyclic voltammetry and chronoamperometry onto glassy carbon electrode from the DES. From the voltammetric study, typical reduction and oxidation stages were identified. From the behavior of experimental current density transients, it was found that the Co electrodeposition could be described by a model comprising Co three-dimensional nucleation and diffusion-controlled growth taking into account the induction – time. The diffusion coefficient of cobalt ions in DES was determined by two methods: cyclic voltammetry and kinetic parameters obtained from model fitting. Moreover, the dimensionless analyses of the experimental current density transients have shown the dominance of progressive nucleation type during the electrodeposition of cobalt. Characterization techniques such as scanning electron microscopy, energy-dispersive X-ray spectroscopy, and elements mapping were used to verify the presence and the nucleation type of cobalt onto the glassy carbon electrode surface, showing a good agreement with the prediction made from the proposed model. This also corroborates the feasibility of the proposed methodology for studying the electronucleation of metals.2022-01-01T00:00:00ZNeolignans from the seeds of Myristica fragrans Houtt
https://dspace.ctu.edu.vn/jspui/handle/123456789/97642
Title: Neolignans from the seeds of Myristica fragrans Houtt
Authors: Pham, Van Cong; Ngo, Van Hieu; Ngo, Viet Duc; Pham, Thuy Ha; Do, Thanh Tuan; Nguyen, Thi Thu Hien; Hoang, Le Tuan Anh
Abstract: Myristica fragrans Houtt. is an aromatic evergreen tree that belongs to the Myristicaceae family. The seeds of this plant have been widely used in culinary field as a spice and in folk medicine for treating several diseases such as stomachic, stimulant, carminative, intestinal catarrh and colic, headaches, and diarrhea, and so on. In this study, seven neolignans including one new, maceneolignan L (1), and six known neolignans: erythro-(7S,8R)-∆8ʹ-4,7-dihydroxy-3,3',5'-trimethoxy-8-O-4'-neolignan (2), rhaphidecursinol B (3), maceneolignan H (4), maceneolignan F (5), (+)-(4-hydroxy-3-methoxy-1'-allyl-3',5'-dimethoxy)-8-O-4'-neolignan (6), (±) licarin A (7) were isolated from the seeds of M. fragrans Houtt. The structures of the compounds were determined by comprehensive spectroscopic analyses of their 1D-, 2D- NMR and high-resolution mass spectrometry (HR-EI-MS).2022-01-01T00:00:00ZAntioxidant, lipid peroxidation inhibitory activities, and hepatoprotective effect of extracts of Phyllanthus emblica L. fruits
https://dspace.ctu.edu.vn/jspui/handle/123456789/97604
Title: Antioxidant, lipid peroxidation inhibitory activities, and hepatoprotective effect of extracts of Phyllanthus emblica L. fruits
Authors: Nguyen, Manh Cuong; Pham, Ngoc Khanh; Tran, Thu Huong; Vu, Thi Ha; Hoang, Thi Ngoc Anh; Do, Thi Thao; Do, Thi Cuc; To, Dao Cuong
Abstract: Phyllanthus emblica L., commonly known by Vietnamese people as “Me rừng” or “Me mận”, is widely distributed in Viet Nam and has been used in folk medicines for treatment of numerous ailments. The preparation of P. emblica fruit extracts in different solvent types have significant effects on extraction efficiency, phytochemical profile, and biological activity. This study aims to investigate the effects of six different solvents (methanol, ethyl acetate, water, 50 %, 70 %, and 96 % ethanol) used in the production of the corresponding extracts, denoted PE-M, PE-EA, PE-W, PE-50Et, PE-70Et, and PE-96Et, respectively) on phytochemical yield, in vitro antioxidant capacity, ex vivo lipid peroxidative inhibitory activity, and hepatoprotective potential of P. emblica fruits collected in Viet Nam. Our results showed that the PE-M and PE-96Et extracts of P. emblica fruits possessed the highest total phenolic content (321.6 and 287.9 GAE mg/g, respectively). However, because of its low toxicity, PE-96Et turned into the best potential candidate with DPPH antioxidant capacity (SC50 of 4.17 µg/mL), lipid peroxidative inhibitory activity via MDA assay (IC50 of 3.54 µg/mL), and hepatoprotective activity on CCl4 intoxicated liver platform (PC50 of 56.6 µg/mL). The HPLC-MS profiles of the PE-M and the PE-96Et extracts showed the presence of mucic acid 3-O-gallate (1), mucic acid 2-O-gallate (2), mucic acid 1,4-lactone 3-O-gallate (3), glucogallin (4), mucic acid 1,4-lactone 2-O-gallate (5), gallic acid (6), mucic acid dimethyl ester 3-O-gallate (7), mucic acid 1,4-lactone 1-ethyl ester 2-O-gallate (8), and quercetin (9). The results indicated that the 96 % ethanol extract of P.emblica fruits is highly potential for further investigation and development of hepatoprotective products.2022-01-01T00:00:00Z