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Antidiabetic and antioxidant activities of red seaweed Laurencia dendroidea

Asian Pacific Journal of Tropical Biomedicine 2019年第12期9卷 501-509页

作者： The Han Nguyen thi Huyen Nguyen van Minh Nguyen thi Lan Phuong Nguyen thi van anh tran anh Duy Do Sang Moo Kim Faculty of Food Technology Nha Trang University02 Nguyen Dinh Chieu StreetNha Trang CityKhanh HoaVietnam Quality Control Department Institute of Vaccines and Medical BiologicalsNha Trang CityKhanh HoaVietnam Faculty of Pharmacy University of Medicine and Pharmacy of Ho Chi Minh City41 Dinh Tien Hoang StreetHo Chi Minh CityVietnam Research Department of Marine Conservation Research Institute for Marine Fisheries224 Le Lai StreetHai Phong CityVietnam Department of Marine Food Science and Technology Gangneung-Wonju National University7 Jukheon-gilGangneung 25457Republic of Korea

Objective:To investigate antidiabetic and antioxidant activities of the extract and fractions from Vietnamese red seaweed Laurencia ***:The seaweed Laurencia dendroidea was extracted by using microwave-assisted extraction method in 80%*** seaweed extract was then fractionated using different solvents(n-hexane,chloroform,ethyl acetate,butanol and water).These obtained fractions were evaluated forα-glucosidase inhibitory and antioxidant *** activities were tested using DPPH,nitric oxide radical scavenging and metal chelating *** enzyme inhibition mode was determined using Lineweaver-Burk *** acidic and thermal stabilities,the ethyl acetate fraction was treated at pH 2.0 and 100℃,*** residual inhibitory activity of the fraction was calculated based on the initial inhibitory *** in vivo antidiabetic activity,mice were divided into four groups,including normal control,diabetic control,diabetic mice treated with ethyl acetate fraction and diabetic mice treated with *** glucose level of treated mice during acute and prolonged treatments was *** evaluate the toxicity of the ethyl acetate fraction,the body weight changes and activities of liver function enzymes(aspartate transaminase,alanine transaminase and gammaglutamyl transferase)were carried ***:The extract of Laurencia dendroidea showed strongα-glucosidase inhibitory and DPPH radical scavenging *** concentrations affected bothα-glucosidase inhibitory and antioxidant activities.A 80%aqueous methanol was the suitable solvent for extraction of enzyme inhibitors and *** solvent fractions,ethyl acetate fraction had the highest inhibitory activities againstα-glucosidase with a mixed type of inhibition and the strongest antioxidant activities,and was stable under acidic and thermal *** ethyl acetate fraction treated diabetic mice significantly reduced blood glucose level compare

关键词： α-Glucosidase inhibitor Antidiabetic Antioxidant Red seaweeds Vietnam

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Study on the tunnel shape and soil-lining interaction influencing the lining behavior under seismic loading

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Earthquake Engineering and Engineering Vibration 2024年第4期23卷 845-862页

作者： van Vi Pham Ngoc anh Do Piotr Osinski Ngoc Thai Do Daniel Dias Sustainable Development in Underground Engineering Research Team Hanoi University of Mining and GeologyHanoiVietnam Department of Underground and Mining Construction Faculty of Civil EngineeringHanoi University of Mining and GeologyHanoiVietnam Department of Geotechnical Engineering Institute of Civil EngineeringWarsaw University of Life Sciences-SGGWWarszawaPoland Laboratory 3SR Grenoble Alpes UniversityGrenoble 38400France

The response of tunnels subjected to seismic loading is a complex mechanism and depends not only on the seismic nature but also on tunnel structure and surrounding soil *** individual behavior of circular,rectangular,and sub-rectangular tunnels subjected to seismic loadings has already been studied in the *** the present research,two case scenarios of circular,rectangular tunnels and four sub-rectangular shaped tunnels,with similar cross-section areas,were adopted to perform a comprehensive numerical *** purpose of the study was to determine the mechanical behavior of tunnels of different shapes,depending upon seismic *** were performed by considering the influence of soil-lining interaction,soil parameters,and lining thickness,as well as lining *** were performed for no-slip and full-slip *** results indicate that the tunnel shape design is of great importance when regarding the mechanical behavior of the surrounding *** concerns no-slip as well as full-slip soil-lining interaction,especially when the lining is subjected to seismic ***,it is shown that changes in incremental bending moments for circular,rectangular and sub-rectangular tunnels that depend upon the soil-lining interaction conditions differ significantly.

关键词： tunnel shape soil-lining interaction seismic loading internal forces numerical analysis

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Assessment of different machine learning techniques in predicting the compressive strength of self-compacting concrete

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Frontiers of Structural and Civil Engineering 2022年第7期16卷 928-945页

作者： van Quan tran Hai-van thi MAI Thuy-anh NGUYEN Hai-Bang LY Faculty of Civil Engineering University of Transport TechnologyHanoi 100000Vietnam

The compressive strength of self-compacting concrete(SCC)needs to be determined during the construction design *** paper shows that the compressive strength of SCC(CS of SCC)can be successfully predicted from mix design and curing age by a machine learning(ML)technique named the Extreme Gradient Boosting(XGB)algorithm,including non-hybrid and hybrid *** ML techniques,such as Linear regression(LR),K-Nearest Neighbors(KNN),Support Vector Machine(SVM),Decision Trees(DTR),Random Forest(RF),Gradient Boosting(GB),and Artificial Neural Network using two training algorithms LBFGS and SGD(denoted as ANN_LBFGS and ANN_SGD),are also compared with the XGB ***,the hybrid models of eight ML techniques and Particle Swarm Optimization(PSO)are constructed to highlight the reliability and accuracy of SCC compressive strength prediction by the XGB_PSO hybrid *** highest number of SCC samples available in the literature is collected for building the ML *** with previously published works’performance,the proposed XGB method,both hybrid and non-hybrid models,is the most reliable and robust of the examined techniques,and is more accurate than existing ML methods(R2=0.9644,RMSE=4.7801,and MAE=3.4832).Therefore,the XGB model can be used as a practical tool for engineers in predicting the CS of SCC.

关键词： compressive strength self-compacting concrete machine learning techniques particle swarm optimization extreme gradient boosting

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BTEX pollution caused by motorcycles in the megacity of HoChiMinh

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Journal of Environmental Sciences 2013年第2期25卷 348-356页

作者： tran thi Ngoc Lan Pham anh Minh University of Science Vietnam National University227 Nguyen Van CuHoChiMinh 70000Vietnam

Monitoring of benzene, toluene and xylenes （BTEX） was conducted along with traffic counts at 17 roadside sites in urban areas of HoChiMinh. Toluene was the most abundant substance, followed by p,m-xylenes, benzene, o-xylene and ethylbenzene. The maximum observed hour-average benzene concentration was 254 μg/m3 . Motorcycles contributed to 91% of the traffic fleet. High correlations among BTEX species, between BTEX concentrations and the volume of on-road motorcycles, and between inter-species ratios in air and in gasoline indicate the motorcycle-exhaust origin of BTEX species. Daily concentrations of benzene, toluene, ethylbenzene, p,m-xylenes and o-xylene were 56, 121, 21, 64 and 23 μg/m 3 , respectively. p,m-xylenes possess the highest ozone formation potential among the BTEX family.

关键词： air pollution benzene BTEX HoChiMinh motorcycle exhaust

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Quadruple[6]Helicene Featuring Pyrene Core:Unraveling Contorted Aromatic Core with Larger Effective Conjugation

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Precision Chemistry 2024年第9期2卷 488-494页

作者： Christopher Wallerius Otgonbayar Erdene-Ochir Eva van Doeselar Ronald Alle anh Tu Nguyen Marvin F.Schumacher Arne Lützen Klaus Meerholz Sai Ho Pun Department of Chemistry University of CologneCologne 50939Germany Kekulé-Institute of Organic Chemistry and Biochemistry University of BonnBonn 53121Germany Department of Chemistry Hong Kong University of Science and TechnologyClean Water BayHong KongChina

Multiple helicenes display distinct aromatic cores characterized by highly twisted rings that are shared or fused with constituent helicene *** these aromatic cores unlocks avenues for creating multiple helicenes with distinct properties and *** we report the synthesis of a quadruple[6]helicene featuring pyrene as the aromatic *** synthesis involved key steps of the annulativeπ-extension reaction and Scholl *** extending multiple helicenes along the axial direction,the degree of contortion of the aromatic core can be controlled from nearly flat to highly ***,quadruple[6]-helicene exhibits a significant red-shift of 0.49 eV compared to quadruple[4]-helicenes,of which the red-shift arises from bothπ-extension and augmented effective conjugation due to enhanced *** chemical calculations demonstrate that the degree of contortion in the pyrene core adeptly governs the energy levels of the HOMO and LUMO,which offers an alternative strategy beyond mere enlargement of theπ*** intriguing serendipitous finding reveals the formation of one-molecule-thick supramolecular homochiral nanosheets through selfinterlocking interactions of enantiomers in single crystals,a rare packing motif for multiple helicenes.

关键词： Helicenes Polycyclic aromatics Pyrene Core contortion Effective conjugation

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Investigation of Polymorphisms in Coding Region of OsHKT1in Relation to Salinity in Rice

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Rice science 2016年第6期23卷 334-338页

作者： pham quynh-hoa tran xuan-an nguyen thi-nha-trang tran thi-thuy-anh hoang hai-yen nguyen thi-hong-van tang thi-hanh do thi-phuc Faculty of Biology VNU University of ScienceHanoi334 Nguyen TraiThanh XuanHanoiVietnam Faculty of Agronomy Vietnam National University of AgricultureNgo Xuan Quang StreetTrau QuyGia LamHanoiVietnam

Rice （Oryza sativa） is sensitive to salinity, but the salt tolerance level differs among cultivars,which might result from natural variations in the genes that are responsible for salt tolerance. High-affinitypotassium transporter （HKTs） has been proven to be involved in salt tolerance in plants. Therefore, wescreened for natural nucleotide polymorphism in the coding sequence of OsHKT1, which encodes the HKTprotein in eight Vietnamese rice cultivars differing in salt tolerance level. In total, seven nucleotidesubstitutions in coding sequence of OsHKT1 were found, including two non-synonymous and five synonymoussubstitutions. Further analysis revealed that these two non-synonymous nucleotide substitutions （G50Tand T1209A） caused changes in amino acids （Gly17Val and Asp403Glu） at signal peptide and the loop ofthe sixth transmembrane domain, respectively. To assess the potential effect of these substitutions on theprotein function, the 3D structure of HKT protein variants was modelled by using PHYRE2 webserver. Theresults showed that no difference was observed when compared those predicted 3D structure of HKTprotein variants with each other. In addition, the codon bias of synonymous substitutions cannot clearlyshow correlation with salt tolerance level. It might be interesting to further investigate the functional roles ofdetected non-synonymous substitutions as it might correlate to salt tolerance in rice.

关键词： polymorphism salt stress OsHKT1 gene rice

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Microwave absorption of magnesium/hydrogen-treated titanium dioxide nanoparticles

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Nano Materials Science 2019年第1期1卷 48-59页

作者： Michael Green anh thi van tran Russell Smedley Adam Roach James Murowchick Xiaobo Chen Department of Chemistry University of Missouri-Kansas City Kansas City MO 64110 USA Department of Geosciences University of Missouri-Kansas City Kansas City MO 64110 USA

Interactions between materials and electromagnetic irradiations in the microwave frequency are critical for many civil and military applications, such as radar detection, communications, information processing and transport et al. Dipole rotations or magnetic domain resonance are the mainly traditional mechanisms for microwave absorption. The recent finding of the excellent microwave absorption from hydrogenated TiO2 nanoparticles provides us an alternative approach for achieving such absorption, by manipulating the structural defects inside nanoparticles through hydrogenation. In this study, we demonstrate that the microwave absorption can be not only achieved but fine-tuned with TiO2 nanoparticles thermally treated in a Mg/H2 environment. Their position and efficiency can be effectively controlled by the treating temperature. Specifically, the microwave absorption position shifts to the lower frequency region as the treating temperature increases, and there seems to exist an optimal treating temperature to obtain the maximum efficiency, as the absorbing efficiency first increases, and then decreases, with the increase in treatment temperature. Therefore, this study enriches our knowledge and understanding microwave absorption from TiO2-based nanomaterials which may inspire new ideas on other systems to enhance their performance as well.

关键词： Hydrogenation Reflection loss Permittivity Permeability Microwave absorption

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Predicting shear strength of slender beams without reinforcement using hybrid gradient boosting trees and optimization algorithms

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Frontiers of Structural and Civil Engineering 2022年第10期16卷 1267-1286页

作者： Thuy-anh NGUYEN Hai-Bang LY van Quan tran Department of Civil Engineering University of Transport TechnologyHanoi 100000Vietnam

Shear failure of slender reinforced concrete beams without stirrups has surely been a complicated occurrence that has proven challenging to adequately *** primary purpose of this work is to develop machine learning models capable of reliably predicting the shear strength of non-shear-reinforced slender beams(SB).A database encompassing 1118 experimental findings from the relevant literature was compiled,containing eight distinct *** Boosting(GB)technique was developed and evaluated in combination with three different optimization algorithms,namely Particle Swarm Optimization(PSO),Random Annealing Optimization(RA),and Simulated Annealing Optimization(SA).The findings suggested that GB-SA could deliver strong prediction results and effectively generalizes the connection between the input and output *** values and two-dimensional PDP analysis were then carried *** may use the findings in this work to define beam’s geometrical components and material used to achieve the desired shear strength of SB without reinforcement.

关键词： slender beam shear strength gradient boosting optimization algorithms

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Upconversion luminescence of Gd2O3:Er3+and Gd2O3:Er3+/silica nanophosphors fabricated by EDTA combustion method

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Journal of Rare Earths 2019年第11期37卷 1126-1131页

作者： Le Quoc Minh tran Kim anh Nguyen Duy Hung Pham thi Minh Chau Nguyen thi Quy Hai Ho van Tuyen Vu thi Thai Ha Vu Duc Tu Wieslaw Strek Institute of Theoretical and Applied Research Duy Tan UniversityDa Nang 55000Viet Nam Advanced Institute for Science and Technology Hanoi University of Science and Technology1 Dai Co VietHai Ba TrungHanoiViet Nam Institute of Materials Science Vietnam Academy of Science and Technology18 Hoang Quoc Viet RoadCau Giay DistrictHanoiViet Nam Institute of Low Temperature and Structure Research Polish Academy of Science 2 OkolnaWroclawPoland

Gd2O3:Er^3+nanophosphors were fabricated by the combustion method in presence of Na2 ethylene diamine tetra acetic acid(EDTA-Na2)as fuel at not high temperature(≤350℃)within a very short time of 5 *** added concentration of Er^3+ions in Gd2O3 matrix was changed from 0.5 mol%to 5.0 mol%.The X-ray diffraction pattern of samples indicates the monoclinic structure of Gd2O3:Er^3+.The morphology and chemical composition analysis of the Gd2O3:Er^3+samples are characterized by a field emission scanning electron microscope(FESEM)and a Fourier-transform infrared spectrometer(FTIR).The photoluminescence(PL),photo luminescence excitation(PLE)and upconversion(UC)at room temperature of the prepared materials with different concentrations of Er^3+were *** PL of Gd2O3:Er^3+nanomaterials are shown in visible at 545,594,623,648,688 nm under excitation at 275 *** emission bands from transitions of Er^3+from 2P3/2 to 4F9/2 are observed,UC luminescent spectra of the Gd2O3:Er^3+/silica nanocomposites under 976 nm excitation show the bands at 548 and 670 *** influence of excitation power at 980 nm for transitions were measured and *** results indicate that the upconversion process of Gd2O3:Er^3+/silica is two photons absorption *** low temperature dependence of UC luminescent intensities of the main bands of Gd2O3:Er^3+was investigated towards development of a nanotemperature sensor in the range of 10-300 K.

关键词： Upconversion luminescence Gd2O3:Er3+ Gd2O3:Er3+/silica Nanophosphors EDTA combustion Rare earths

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LiMn_2O_4/CNTs and LiNi_(0.5)Mn_(1.5)O_4/CNTs Nanocomposites as High-Performance Cathode Materials for Lithium-Ion Batteries

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Acta Metallurgica Sinica(English Letters) 2015年第1期28卷 122-128页

作者： Thang van Le Ha tran Nguyen anh Tuan Luu Man van tran Phung Loan My Le Faculty of Materials Technology Ho Chi Minh University of Technology 268 Ly Thuong Kiet Ward 14 District 10 Ho Chi Minh City Vietnam Department of Physical Chemistry University of Science VNUHCM 227 Nguyen Van Cu Street District 5 Ho Chi Minh CityVietnam

The demand of higher energy density and higher power capacity of lithium（Li）-ion secondary batteries has led to the search for electrode materials whose capacities and performance are better than those available today. Carbon nanotubes（CNTs）, with their unique properties such as 1D tubular structure, high electrical and thermal conductivities, and extremely large surface area, have been used as materials to prepare cathodes for Li-ion batteries. The structure and morphology of CNTs were analyzed by X-ray diffraction（XRD）, scanning electron microscopy（SEM）, and transmission electron microscopy（TEM）. The functional groups on the purified CNT surface such as –COOH, –OH were characterized by Fourier transform infrared spectroscopy. The electrode materials were fabricated from LiMn2O4（LMO）, doped spinel LiNi0.5Mn1.5O4, and purified CNTs via solid-state reaction. The structure and morphology of the electrode were characterized using XRD, SEM, and TEM. Finally, the efficiency of the electrode materials using CNTs was evaluated by cyclic voltammetry and electrochemical impedance spectroscopy.

关键词： Nanocomposites Carbon nanotubes(CNTs) Spinel materials Lithium-ion batteries(LIBs)

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