Science and Technology Development Journal 2021-04-15T15:40:46+00:00 Phuc Van Pham Open Journal Systems Fractionation of lignin produced from the Earleaf Acacia tree by sequential industrial organic solvents 2021-04-15T15:40:45+00:00 Thong Hoang Le Khanh B. Vu Quynh-Thy Song Nguyen Phat Van Huynh Khanh-Ly T. Huynh Khoa Dang Tong Thong Le Minh Pham An Tran Nguyen Minh Van Cuong Nguyen Thanh Khoa Phung <p><strong>Introduction: </strong>Understanding the fractions of lignin is important for further conversion of lignin into valuable products. Herein, the “home-made” lignin from Earleaf Acacia tree was extracted by sequential industrial organic solvent and characterized each fraction to reveal its properties for further catalytic applications.</p> <p><strong>Methods: </strong>In this work, lignin was prepared from the Earleaf Acacia tree using the soda method. Then, the prepared lignin was fractionated by sequential solvents of ethyl acetate, ethanol, methanol, and acetone. Each lignin fractions were characterized by FT-IR and GPC.</p> <p><strong>Results: </strong>The FT-IR results confirmed the soda method can produce lignin from woodchips. The fractionation of lignin separated the lignin mixture into different molecular weight fraction from light – medium into heavy compounds.</p> <p><strong>Conclusion: </strong>Lignin was produced from woodchips using the soda method successfully. The fractionation using the sequential organic solvents showed the separation of different molecular weight of lignin, which allow to apply for the further conversion into useful products.</p> 2021-02-22T23:04:01+00:00 ##submission.copyrightStatement## Density functional theory insights into the bonding of CH3OH and CH3O with Ir(111) surface 2021-04-15T15:40:46+00:00 Thong Le Minh Pham Khoa Thanh Phung Thang Viet Ho Thi Anh Le An Thai Thi Nguyen <p><strong>Introduction</strong>: Understanding the adsorption characteristics of CH3OH and CH3O on the noble metal surfaces is essential for designing better catalysts for the on-board production of hydrogen from CH3OH. This study aims to provide insights into the adsorption behavior of these molecules on Ir(111) surface.</p> <p><strong>Methods</strong>: The adsorption structure, the adsorption energy, and the bonding mechanism of CH3OH and CH3O with Ir(111) surface were investigated by means of the density functional theory (DFT) calculations and the Bader charge analysis.</p> <p><strong>Results</strong>: The DFT results show that the adsorption of CH3OH and CH3O is driven by the formation of Ir–O bond at the top site of the surface by the overlap of O-2p and Ir-5d orbitals. The overlap of these orbitals is greater in the absorption of CH3O, resulting in stronger adsorption energy of CH3O (2.23 eV vs. 0.32 eV). In agreement with the adsorption strength, the charge transfer from CH3O to the surface is significantly larger than from CH3OH (0.386 e vs. 0.073 e).</p> <p><strong>Conclusion</strong>: Although driven by the same adsorption bond, the difference in the molecular characteristics leads to a marked difference in the absorption strength of CH3OH and CH3O on Ir(111) surface.</p> 2021-02-02T00:00:00+00:00 ##submission.copyrightStatement## Phenolic compounds from the lichen Parmotrema tinctorum 2021-04-15T15:40:44+00:00 Huynh Bui Linh Chi Van Muoi Bui Thi Quynh Nhu Phan Kim Phi Phung Nguyen <p><strong>Introduction</strong>: The metabolites of lichens concentrated depsidones, depsides, and diphenyl ethers were possessed antibiotic, antifungal, antiviral, antitumor, and anticancer activities. Parmotrema tinctorum (Despr. ex Nyl.) Hale, a species of foliose lichen, is widely distributed in Lam Dong province, Vietnam. Herein, this paper describes the isolation and structure elucidation of seven compounds isolated from this lichen. <strong>Methods</strong>: Phytochemical investigations of the ethyl acetate extract of the lichen P. tinctorum led to the isolation of seven pure compounds. Their chemical structures were elucidated by extensive HR-ESI-MS and NMR spectroscopic analysis and comparison with previously published data. <strong>Results</strong>: Seven compounds, namely orcinol (1), orsellinic acid (2), methyl orsellinate (3), methyl heamatomate (4), lecanorin (5), lecanoric acid (6), and gyrophoric acid (7). These compounds were determined the α-glucosidase inhibitory activity. <strong>Conclusions</strong>: Compound 7 was determined for the first time in P. tinctorum, and this was also the first time these compounds were determined the α-glucosidase inhibitory activity.</p> 2021-02-25T22:43:27+00:00 ##submission.copyrightStatement## Transfer hydrogenation of benzaldehyde over embedded copper nanoparticles 2021-04-15T15:40:42+00:00 Thanh Thien Co <p>Transfer hydrogenation is one of the reactions of high industrial application and copper catalyst is widely used in variety of hydrgenated substrates. Unfortunately, these hydrogenated processes were usually performed at high temperature and pressure as well as high concentration of catalyst. In this study, we have tried to reduce the dangerous condition by using copper nanoparticles as catalyst and the catalytic activity will be evaluated via the transfer hydrogenation of benzaldehyde. Besides, copper nanoparticles were successful prepared by the reduction between CuSO<sub>4</sub>.5H<sub>2</sub>O and NaBH<sub>4</sub> in the presence of PVP. All catalysts were fully characterized.</p> 2021-02-28T07:54:32+00:00 ##submission.copyrightStatement## Improvement of antibacterial efficacy using antibiotic encapsulated silica-containing redox nanoparticles 2021-04-15T15:40:41+00:00 Han Ngoc Tran Nhu-Thuy Trinh Hoai-Ngan Thien Pham Hanh Thi Ngoc Nguyen Vong Binh Long <p><strong>Purpose</strong>: Improving solubility and antibacterial efficiency of cephalothin by using silica-containing redox nanoparticle (siRNP) as a system to encapsulate and deliver this hydrophobic antibiotic.</p> <p><strong>Methods</strong>: siRNP was synthesized by assembling amphiphilic block copolymers possessing a reactive oxygen species scavenging nitroxide radical and drug absorptive silica moieties in a hydrophobic side chain. Cephalothin, a hydrophobic antibiotic, was encapsulated into siRNP (cephalothin@siRNP) by mixing and dialysis methods. Antibacterial activity of cephalothin@siRNP against <em>Staphylococcus aureus</em> (<em>S. aureus</em>) và <em>Escherichia coli</em> (<em>E. coli</em>) was evaluated by the agar diffusion method.</p> <p><strong>Results</strong>: The average size of siRNP and cephalothin@siRNP was 43.83 nm and 50.15 nm, respectively. After encapsulation in siRNP, the solubility of cephalothin was improved compared to cephalothin in an aqueous solution. The result showed that in vitro antibacterial activities of cephalothin and cephalothin@siRNP had no statistical difference after 24 h incubation on agar plates on both <em>S. aureus</em> and <em>E. coli</em>. However, after an extended incubation time, regrowth of <em>E. coli</em> colonies in the inhibitory zone was found in cephalothin treated plate. Interestingly, <em>E. coli</em> regrowth was significantly reduced in plates treated with cephalothin@siRNP.</p> <p><strong>Conclusion</strong>: In this study, siRNP successfully encapsulated cephalothin and enhanced the solubility of this drug. The antibacterial activity of cephalothin is prolonged when encapsulated in siRNP, which suppressed the reccurrence of <em>E. coli</em> colonies. Cephalothin@siRNP has the potential to inhibit antibiotic resistance.</p> 2021-03-11T00:00:00+00:00 ##submission.copyrightStatement## Gold nanoparticles enhanced fluorescence for highly sensitive biosensors based on localized surface plasmon resonance applied in determination C-reactive protein 2021-04-15T15:40:40+00:00 Nhu Hoa Thi Tran Phuong Que Do Tran Bach Thang Phan Hanh Kieu Thi Ta Ngoc Xuan Dat Mai Lai Thi Hoa Thanh Van Thi Tran Dung Van Hoang <p><strong>Introduction: </strong>C-reactive protein (CPR) is known as an inflammation marker related to numerous pathology. Optical biosensor based on the fluorescence dyed is widely used in diagnosis. There are still limitations on the fluorescence signal detection due to the photobleaching effect. The localized surface plasmon resonance (LSPR) performed by gold nanoparticles (Au NPs) is testified for the enhancement of photo-signal gathered from the dye molecules.</p> <p><strong>Methods: </strong>In this study, Au NPs were used for their significant optical properties and biocompatibility additionally. The seed-mediated synthesis method provided stable NPs with all the essential qualities. A series of modification steps were done on a glass substrate before the bio-bonding for fluorescence-based sensing by a transmission mode (T-mode) detection system which is introduced for the first time in Viet Nam.</p> <p><strong>Results: </strong>The synthetic Au NPs in nanosphere structure evinced the absorbance at a maximum wavelength is 521 nm. All the followed alterations showed the accomplishment in forming the in need linking proved through the basic analysis methods. Finally, CRP with the Alexa 488 dye was observed for average at 4.8 folds of enhancement factor compared between the Au NPs coating and non-coating substrate detected by the T-mode system. The low coefficient of variation at under 0.7% appeared for the repeatability and stability of this sensor.</p> <p><strong>Conclusion: </strong>The completely modern approach of the T-mode system combined with the LSPR applied in fluorescence sensors enhanced is developed successfully. Also, the future prospect of this designed sensing method is promising by changing the materials' structures and ingredients.</p> <p><strong>Keywords:</strong> LSPR, gold nanoparticles, fluorescence enhancement, C-reaction protein, optical biosensors</p> 2021-03-17T00:00:00+00:00 ##submission.copyrightStatement##