Science and Technology Development Journal http://stdj.scienceandtechnology.com.vn/index.php/stdj <p><span id="result_box" class="" lang="en"><span title="Tạp chí Phát triển Khoa học và Công nghệ (PTKH&amp;CN) của Đại học Quốc gia thành phố Hồ Chí Minh (ĐHQG-HCM) được thành lập từ năm 1997, ra số đầu tiên vào tháng 1 năm 1998. Từ năm 2006 Tạp chí đã"><strong>Science and Technology Development Journal</strong> (STDJ), Vietnam National University - Ho Chi Minh City (VNU-HCM) was established in 1997. And the first issue was published in January 1998 with </span><span title="đăng ký mã số chuẩn quốc tế ISSN 1859-0128.">ISSN 1859-0128. </span><span title="Từ đó cho đến nay, Tạp chí PTKH&amp;CN đã trở thành diễn đàn khoa học quan trọng nhất của đội ngũ cán bộ nghiên cứu, giảng viên, nghiên cứu sinh của ĐHQG-HCM và cũng là diễn đàn khoa học công nghệ đáng tin cậy của">Since then, STDJ has become the most important scientific forum of scientists from VNU-HCM as well as</span><span title="nhiều nhà nghiên cứu, giảng viên các trường đại học khác tại Việt Nam."> other universities. </span><span title="Tạp chí đã trải qua 20 năm phát triển và đã trở thành nhịp cầu giao lưu khoa học, cũng như làm phong phú tài liệu tham khảo cho đội ngũ giảng viên, nghiên cứu sinh, sinh viên ĐHQG-HCM nói riêng và các Trường đại">The magazine has undergone 20 years of development and has become a bridge for scientific exchanges, as well as enriching reference materials for the faculty, doctoral students, students of VNU-HCM in particular and other universities, institutes... </span></span></p> <p><span id="result_box" class="" lang="en"><span title="học phía Nam nói chung. "><br></span><span title="Tính đến hết năm 2016 Tạp chí đã xuất bản được 276 số với 2714 bài nghiên cứu của các nhà khoa học, cán bộ trong và ngoài ĐHQG-HCM trong 5 lĩnh vực nghiên cứu: Kỹ thuật và Công nghệ, Khoa học Tự nhiên,">By the end of 2016, the journal has published 276 issues with 2714 research articles in five areas of research: Engineering and Technology, Natural Sciences, </span><span title="Khoa học Xã hội và Nhân văn, Kinh tế luật và Khoa học Quản lý, Khoa học Trái đất và Môi trường tương ứng với 5 chuyên san chuyên ngành của Tạp chí.">Social Sciences and Humanities, Economics of Law and Management Sciences, Earth Sciences and Environment corresponding to 5 specialized journals of the Journal. </span></span></p> <p><span id="result_box" class="" lang="en"><span title="Tạp chí đã được phát hành tại các thư viện của các đơn vị thành viên của ĐHQG-HCM, các Sở Khoa học Công nghệ của các tỉnh thành trên cả nước và được Hội đồng học hàm Giáo sư Nhà nước đánh giá cao.">The magazine has been widely indexed in the various libraries at Vietnam. </span></span></p> <p><span id="result_box" class="" lang="en"><span title="Từ tháng 12/2006 Tạp chí đã nhận được sự giúp đỡ của tổ chức mạng quốc tế về các xuất bản phẩm khoa học thuộc Hội đồng khoa học quốc tế để tham gia vào mạng lưới các Tạp chí Khoa học quốc tế. "><br></span><span title="Hiện nay tạp chí bao gồm 5 chuyên san sau đây: ">The journal currently consists of the following five sections:<br></span><span title="• Kỹ thuật và Công nghệ, ">• Engineering and Technology</span></span></p> <p><span id="result_box" class="" lang="en"><span title="• Khoa học Tự nhiên, ">• Natural Sciences</span></span></p> <p><span id="result_box" class="" lang="en"><span title="• Khoa học Xã hội và Nhân văn, ">• Social Sciences and Humanities</span></span></p> <p><span id="result_box" class="" lang="en"><span title="• Kinh tế luật và Khoa học Quản lý, ">• Economics, Law and Management</span></span></p> <p><span id="result_box" class="" lang="en"><span title="• Khoa học Trái đất và Môi trường">• Sciences of Earth and Environment</span></span></p> <p><span class="" lang="en"><span title="• Khoa học Trái đất và Môi trường"><span id="result_box" class="" lang="en">• Health Sciences : It includes work from basic science, clinical science, dental, nursing and other related medical fields. <br></span></span></span></p> Viet Nam National University Ho Chi Minh City en-US Science and Technology Development Journal 1859-0128 <p>Copyright The Author(s) 2018. This article is published with open access by Vietnam National University, Ho Chi Minh city, Vietnam. This article is distributed under the terms of the&nbsp;<a href="https://creativecommons.org/licenses/by/4.0/" target="_blank" rel="noopener">Creative Commons Attribution License (CC-BY 4.0)</a> which permits any use, distribution, and reproduction in any medium, provided the original author(s) and the source are credited.&nbsp;</p> In vitro α-glucosidase inhibitory activity of compounds isolated from mangrove Lumnitzera littorea leaves http://stdj.scienceandtechnology.com.vn/index.php/stdj/article/view/1009 <p><strong>Introduction</strong>: Lumnitzera littorea grown at CanGio Mangrove Forest has been investigated. The present study reports the isolation, characterization and evaluation of the alpha-glucosidase inhibitory activity of isolated compounds from Lumnitzera littorea leaves.</p> <p><strong>Methods</strong>: Their structures were elucidated by spectroscopic methods (including MS, 1D and 2D–NMR) and comparison with values from the literature. From the n-hexane extract, nine compounds including lupeol (<strong>1</strong>), betulin (<strong>2</strong>), betulinic acid (<strong>3</strong>), oleanolic acid (<strong>4</strong>), corosolic acid (<strong>5</strong>), -sitosterol (<strong>6</strong>), beta-sitosterol 3-O- beta-D-glucopyranoside (<strong>7</strong>), stigmast-5-ene-3beta-O-(6-O-hexadecanoyl-beta-D-glucopyranoside) (<strong>8</strong>), and stigmast-4-ene-3-one (<strong>9</strong>) were isolated and identified.</p> <p><strong>Results</strong>: The results of the alpha-glucosidase inhibitory activity showed thatcorosolic acid (5) and oleanolic acid (4) were the most potent, with IC<sub>50</sub> values of 17.86 +/- 0.42 and 18.82 +/- 0.59 ug/mL, respectively. Five of the other seven compounds exhibited inhibitory activity with IC<sub>50</sub> values below 100 ug/mL, and higher than the positive control acarbose (127.64 +/- 0.64 ug/mL).</p> <p>&nbsp;</p> Thuy Thi Le Nguyen Thuy Thi Pham Poul Erik Hansen Phung Kim Phi Nguyen ##submission.copyrightStatement## http://creativecommons.org/licenses/by/4.0 2019-01-07 2019-01-07 22 1 106 113 10.32508/stdj.v22i1.1009 title description none g Physical and electrochemical properties of mixed electrolyte 1-ethyl-3-methylimidazolium Bis(trifluoromethanesulfonyl)imide and ethylene carbonate as electrolytes for Li-ion batteries http://stdj.scienceandtechnology.com.vn/index.php/stdj/article/view/837 <p><strong>Introduction</strong>: Ionic liquids (ILs) have become a prospective candidate to replace the conventional electrolytes based on the volatile organic-solvents in lithium-ion batteries. However, the drawbacks of high viscosity and low ionic conductivity have restricted the high rate capacity and energy density in practical batteries. With the aims to resolve these problems and design a safe electrolytes with high electrochemical stability, mixtures of ionic liquid 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl) imide (EMITFSI) with different amounts of ethylene carbonate (EC) was prepared and characterized as electrolytes for Li-ion batteries.</p> <p><strong>Methods</strong>: In this work, we investigated four factors to demonstrate the performance of EMITFSI as electrolytes for Li-ion batteries. These factors include: thermal properties of mixed electrolytes (Mettler Toledo DSC1 Star -DSC, Q500-TGA), Conductivity (HP- AC impedance spectroscopy), Viscosity (Ostwald viscometer CANNON) and electrochemical window (cyclic voltammetry-MGP2 Biologic Instrument). All experiments were repeated three times with the exception of TGA-DSC methods.</p> <p><strong>Results</strong>: The study indicated that 20 % wt. ethylene carbonate (EC) when mixed with EMITFSI could significantly decrease the electrolyte viscosity while improving ionic conductivity and maintain similar electrochemical stability as pure ionic liquid. Lithium diffusion coefficient of mixed electrolytes was lower than commercial electrolytes based on conventional solvents, however, the thermal stability was enhanced.</p> <p><strong>Conclusion</strong>: EMITFSI can be used to replace conventional carbonate-based liquids as a high-performance electrolyte for Li-ion batteries.</p> <p>&nbsp;</p> Linh Thi-My Le Thanh Duy Vo Hoang Van Nguyen Quan Phung Man Van Tran Phung My Loan Le ##submission.copyrightStatement## http://creativecommons.org/licenses/by/4.0 2019-02-25 2019-02-25 22 1 128 135 10.32508/stdj.v22i1.837 title description none g Phenolic compounds from Pamotrema dilatatum growing in Lam Dong province http://stdj.scienceandtechnology.com.vn/index.php/stdj/article/view/1010 <p><strong>Introduction</strong>: Only chemical study on the lichen Parmotrema dilatatum was found so far in the world. The lichen Parmotrema dilatatum widely distributed in Lam Dong province, Vietnam has been studied about the isolation and elucidation of several metabolites.</p> <p><strong>Methods</strong>: Phytochemical study on the polar fractions of this lichen was carried out by using various chromatographic methods including thin-layer chromatography and normal phase silica gel chromatography.</p> <p><strong>Results</strong>: Eight phenolic compounds were isolated. The chemical structures of isolated compounds were unambiguously elucidated by NMR spectroscopy and comparison with the data in the literature. These are 8'-O-methylsalazinic acid, salazinic acid, 8'-O-methylprotocetraric acid, diffractaic acid, lecanorin, lecanoric acid, isolecanoric acid, and diorcinolic acid.</p> <p><strong>Conclusion</strong>: Among them, 8'-O-methylsalazinic acid was found as a new natural product.</p> <p>&nbsp;</p> Huy Thuc Duong ##submission.copyrightStatement## http://creativecommons.org/licenses/by/4.0 2019-01-26 2019-01-26 22 1 114 119 10.32508/stdj.v22i1.1010 title description none g Long-term expansion enhances the expression of tumor suppressor genes in human bone marrow-derived mesenchymal stem cells http://stdj.scienceandtechnology.com.vn/index.php/stdj/article/view/1661 <p><strong>Introduction</strong>: Mesenchymal stem cells (MSCs) are possibly the most potent type of stem cells for the treatment of many diseases since they possess many advantageous properties, such as abundant source, ease of isolation, and potential to differentiate and trans-differentiate into different types of cells. Although the therapeutic potential of expanded MSCs has been well proven, their biosafety features have not been fully understood. This study aimed to investigate some changes in phenotype and gene expression of bone marrow derived MSCs after long term expansion.</p> <p><strong>Methods</strong>: In this study, expanded mesenchymal stem cells derived from human bone marrow (hBMSCs) were identified for their characteristics (which included morphology, immunophenotype, and differentiation potential) at passages 5, 10 and 15. Moreover, they were evaluated for the expression of various tumor suppressor genes (PTEN, p16, and p53) by real-time RT-PCR.</p> <p><strong>Results</strong>: The results showed that the hBMSCs at passage 15 displayed a change in morphology and a slight reduction of the expression of CD44 and CD90, whereas their potential for adipogenic and osteogenic differentiation was maintained. Moreover, the expression of tumor suppressor genes in the hBMSCs increased after long-term culture.</p> <p><strong>Conclusion</strong>: It could be assumed that prolonged cultures of more than 15 passages drove the hBMSCs into senescence phase. Cultured hBMSCs below passage 10 seemed to be more effective in application because their properties were still preserved.</p> <p>&nbsp;</p> Loan Thi Tung Dang Anh Thi Van Bui Nhat Chau Truong Huy Duc Van Phuc Van Pham ##submission.copyrightStatement## http://creativecommons.org/licenses/by/4.0 2019-03-21 2019-03-21 22 1 136 142 10.32508/stdj.v22i1.1661 title description none g Copolymerization of n-butyl acrylate/methyl methacrylate in xylene solvent http://stdj.scienceandtechnology.com.vn/index.php/stdj/article/view/1020 <p><strong>Introduction</strong>: Copolymers are being used in a variety of fields because of their diversity and since any change could result in significant modifications. The butyl acrylate/methyl methacrylate copolymer is an extensively used polymer system with many advantages. This study aims to analyze some changes in copolymerization, from using different time or temperature of synthesis, in order to find an optimal process that can be applied in Vietnam.</p> <p><strong>Methods</strong>: Copolymerization of butyl acrylate/methyl methacrylate copolymer with different butyl acrylate/methyl methacrylate monomer ratios was done using Xylene solvent. Copolymer compositions were determined from the Proton nuclear magnetic resonance spectra and Gel permeation chromatography.</p> <p><strong>Results</strong>: The experimental results indicate that the copolymer was successfully synthesized. The highest molecular weight was 15,591 g/mol, with the lowest dispersity of 1.53 at 100<sup> o</sup>C after 6 hours of copolymerization.</p> <p>&nbsp;</p> Nguyen-Vu Viet Linh Nguyen Trung Duc Huynh Dai Phu ##submission.copyrightStatement## http://creativecommons.org/licenses/by/4.0 2019-02-17 2019-02-17 22 1 120 127 10.32508/stdj.v22i1.1020 title description none g