bluuebunny/crossref_metadata_2025_split huggingface dataset:
Properties of polymer blends based on devulcanized waste rubber powder (d‐WRP)/EPDM/P
Authors: Dung Nguyen Tuan , Hanh Le Thi My , Lan Pham Thi , Minh Vu Xuan , Van Bien Tran 
Published: February 2020

AbstractIn this study, waste rubber powder (WRP) was devulcanized by ultrasonic in alkaline medium and blended with the different ratios of ethylene‐propylene‐diene copolymer EPDM/PP (polypropylene) and the coupling agent of dicumyl peroxide (DCP) to produce WRD/EPDM/PP polymer blends. With the concentration of 10 wt.% WRP gived the mechanical properties of blends before and after accelerated weathering testing were approxiated with those of EPDM/PP 30/70 blends. The presence of DCP improved the tensile at strength and thermal resistance, caused by interaction between EPDM and PP. Result of thermogravimetric analysis showed that the presence of 0.5 % DCP gaved the maximum thermal resistance of polymer blends up to 380°C.
Chemical constituents from the ethyl acetate extract of the stems of Macaranga balansae Gagnep.
Authors: Thang Pham Toan , Thoa Ha Thi , Giap Tran Huu , Thanh Le Nguyen , Hang Nguyen Thi Minh , Oanh Vu Thi Kim , Huong Tran Thu , Huong Doan Thi Mai , Van Cuong Pham 
Published: February 2020

AbstractThe genus Macaranga, one of the largest genera of the Euphorbiaceae family has approximately 300 species distributed in the tropical regions. Plants of this genus displayed various bioactivities such as antioxidant, antitumor and antimicrobial effects. Macaranga balansae Gagnep. is an endemic plant in Vietnam, that ethyl acetate extract showed cytotoxicity to cancer cell line. In this article, we report the isolation and structural elucidation of six known compounds from the ethyl acetate extract including (‐)‐dehydroxycubebin (1), trans‐coniferyl aldehyde (2), 3,3',4'‐tri‐O‐methyl ellagic acid (3), stigmastane 3β,5α,6β‐triol (4), 2,3‐dihydroxy‐1‐(4’‐hydroxy‐3’‐methoxyphenyl) propan‐1‐one (5), and protocatechuic acid (6). To the best of our knowledge, compounds 1‐5 were isolated from Macaranga genus for the first time.
Isolation of spirostanol glycosides from Solanum nigrum
Authors: Tai Bui Huu , Nhiem Nguyen Xuan , Van Doan Vu , Yen Pham Hai , Quang Tran Hong , Trang Do Thi , Yen Duong Thi Hai , Cuc Nguyen Thi , Van Kiem Phan 
Published: February 2020

AbstractFour spirostanol glycosides, dioscin (1), asperin (2), degalactotigonin (3), and soladulcoside A (4) were isolated from the whole plants of Solanum nigrum. Their chemical structures were elucidated by analyses of their ESI‐MS, NMR spectral data, and comparison with those reported in the literature. This is the first report on the isolation of dioscin and asperin from S. nigrum.
A comparison between the use of continuous and pore network approach in the simulation of the drying process of porous media with different pore size distributions
Authors: Thai Vu Hong , Metzger Thomas , Tsotsas Evangelos 
Published: February 2020

AbstractThe modeling and simulation of the drying process in porous media is seen as one of the most complex and difficult problems in the numerical simulation of engineering processes. The challenge in simulating a drying process comes from the fact that all heat, mass and momentum transfers happen simultaneously and must be taken into account. The numerical simulation of the drying process in porous media can be done by using two different approaches, namely continuous and discrete approach. In the continuous approach, a continuous model is used to build a mathematical system of the porous medium undergoing drying. In this approach the material properties are averaged using the concept of averaging volume. In the discrete approach, a network of pores is considered and no averaging is needed. Each approach has its own advantages and disadvantages. In this work, we compare the use of the continuous and discrete approach in the case the information about the microstructure (pore size) of the porous medium undergoing drying is given and can be taken into account in the continuous model.
Detection of isomerization in commercial natural rubber
Authors: Thuong Nghiem Thi , Nghia Phan Trung , Kawahara Seiichi 
Published: February 2020

AbstractDetection of isomerization in commercial natural rubber (NR) was performed through Nuclear Magnetic Resonance (NMR) spectroscopy in conjunction with structural analysis of pure NR. Three similar grades of commercial NR, which are technically specified rubbers from Vietnam (SVR10), India (SIR10) and Indonesia (ISNR10) and the pure NR, which is prepared by precipitation of rubber latex tapping from Hevea brasisliensis, were used in this work. All the commercial NRs were purified by acetone extraction and the pure NR were prepared by deproteinization and acetone extraction. The 13C‐NMR analysis showed that the main characteristic 13C‐signals of cis‐1,4‐isoprene unit in the polymer chain are unchanged, however, the 13C‐signal at 40 ppm, which is distinguished to the signal at 39.8 ppm, is detected for all commercial rubbers. This signal is assigned to the methyl group of trans‐1,4‐isoprene units as observed in Cariflex‐309 as a model. The appearance of this signal implied the occurrence of isomerization during processing of the commercial NR. The degradation is found to weaken the network structure and result in poor mechanical properties of commercial NR.
Synthesis and properties of some polyethers from chalcones
Authors: Linh Duong Khanh , Dai Do Ba , Vy Do Truc , Chinh Nguyen Thuy , Trung Vu Quoc 
Published: February 2020

AbstractThe monomers chalcones derivatives were synthesized by the condensation reactions of the 4‐hydroxy benzaldehyde and vanillin with p‐hydroxyacetophenone. The monomers were polymerized with dibromoalkanes to give the co‐polyethers containing the photocrosslinkable α, β‐unsaturated carbonyl as photosensitizer group. The structure of polyether was characterized by 1H NMR and 13C NMR spectra. The thermal stability of the polymer was measured by thermogravimetric analysis. The solubility of the polymer in the organic solvents was also studied. The polymers have to be equipped with photosensitive functional groups applied in photopolymers technology.
The effective pH‐responsive 3‐aminopropyltriethoxysilane linked with porous nanosilica for doxorubicine delivery
Authors: Vy Vo Uyen , Van Nguyen Thi Thanh , Linh Nguyen Thuy Thuy , Phan Phan Thi Kim Phuong , Nha Tran Thi Thanh , Lem Pham Hoang Ai , Khoa Nguyen Anh , Hai Nguyen Dai , Khoa Nguyen Cuu 
Published: February 2020

AbstractPorous nanosilica has been identified as an outstanding candidate for controlled drug delivery. However, unmodified PNS‐based carriers usually exhibited an initial release of loaded bioactive agents, which may limit their potential clinical applications. In this study, the surface of porous nanosilica was bonded with 3‐aminopropyltriethoxysilane for Doxorubicin delivery. The modified PNS was successfully formed with spherical shape and diameter around 70 nm determined by Transmission Electron Microscopy. Drug loading and release behaviors of Doxorubicin/ Porous nanosilica‐3‐aminopropyltriethoxysilane, in particular, were also tested. This study is expected to improve the stability of PNS for drug delivery system in cancer therapy.
Synthesis, characterization and antimicrobial activity of copper doped hydroxyapatite
Authors: Nam Pham Thi , Thom Nguyen Thi , Phuong Nguyen Thu , Xuyen Nguyen Thi , Hai Nguyen Song , Anh Nguyen Tuan , Dung Pham Tien , Thanh Dinh Thi Mai 
Published: February 2020

AbstractCopper hydroxyapatite coatings (CuHAp) were synthesized on 316 L stainless steel by electrodepositon and ion exchange methods. Effect of Cu2+ initial concentration and contact time to ion exchange process was investigated. The FTIR, SEM, XRD and EDX measurements of the synthesized samples showed that CuHAp coatings were single crystalline phase of HAp with %Cu of 0.08 (% mass) in Cu2+ initial solution of 0.05 M. The presence of Cu2+ reduced the HAp crystalline size and enabled to obtain samples with more uniform surface. The antimicrobial activity of CuHAp coatings was tested. CuHAp coatings had good resistance to E. coli and S. aureus that antibacterial ratio reached 89 % and 98 %, respectively.
Sesquiterpenoids from the rhizomes of Curcuma aeruginosa
Authors: Boutsada Phoutthalack , Giang Vu Huong , Linh Tran My , Mai Nguyen Chi , Cham Pham Thi , Hanh Tran Thi Hong , Phonenavong Kompheng , Sengchanh Souksakhone , Cuong Nguyen Xuan , Lien Le Quynh , Ban Ninh Khac 
Published: February 2020

AbstractSix sesquiterpenoids were isolated from a methanol extract of Curcuma aeruginosa rhizomes by using various chromatographic separations. Their structures were elucidated as pyrocurzerenone (1), dehydrochromolaenin (2), curzeone (3), linderazulene (4), curzerenone (5), and 8,12‐epoxy‐1 (10),4 (15),7,11‐germacratetraen‐6‐one (6) by extensive NMR spectroscopic analysis as well as comparison with the reported data. This is the first report of isolation of compounds 1, 2, 4, and 6 from C. aeruginosa.
Effect of treatment on quality of black tiger shrimp (Penaeus monodon)
Authors: Tam Le Nhat , Xuan Uyen Phan Thuy , Anh Vu Truong Huynh 
Published: February 2020

AbstractThis study aimed to determine the changes in chemical, microbiological and sensory properties of black tiger shrimp (Penaeus monodon) during storage at 0°C. Two treatment preocedures were used including sodium propionate, sodium acetate. Vacuumn packaging was also investigated. Total volatile basis nitrogen (TVB‐N), trimethylamine nitrogen (TMA‐N), histamine, quality index (QI) and total viable count (TVC) were used to evaluate the quality changes of shrimp throughout storage. The results showed that the values of TVB‐N, TMA‐N, and histamine increased with storage time in two different phases, while QI value increased linearly with preservation time. The quality of shrimp decreased during storage but with different rates. The quality of shrimps treated with salts of organic acids or the sample packed in vacuum bags was significantly higher than that of the control. The shelf‐life of sample treated with 2.5 % sodium acetate orpacked in vacuum packages was 12 days, which was 4 days longer compared to the control.
New naturally occurring phenolic derivatives from marine Nocardiopsis sp. AS23C: Structural elucidation and in silico computational studies
Authors: Eliwa Essam M. , Abdel‐Razek Ahmed S. , Frese Marcel , Halawa Ahmed H. , El‐Agrody Ahmed M. , Bedair Ahmed H. , Sewald Norbert , Shaaban Mohamed 
Published: February 2020

AbstractIn our persistent research for new bioactive secondary metabolites from marine actinomycetes, Nocardiopsis sp. AS23C strain was isolated from the marine Alga Sargassum arnaudianum collected in the Red Sea at Hurghada coast, Egypt. A large‐scale fermentation of the strain on M2 medium containing 50% sea water, followed by fractionation and purification of the obtained extract afforded a new phenolic acid derivative, 4‐amino‐6‐methylsalicylic acid (1a), together with 5‐methylresorcinol (2) and linoleic acid (3). Their molecular structures were proved through the sophisticated spectroscopic analyses including exhaustive 1D and 2D NMR (1 and 2‐Dimensional Nuclear Magnetic Resonance) as well mass spectroscopy techniques. The extract exhibited antibacterial activity against the Gram‐positive Staphylococcus aureus, Bacillus subtilis ATCC6051, and Streptomyces viridochromogenes Tü 57. An in vitro cytotoxicity assaying of 1a and 2 against the human cervix carcinoma cell line (KB‐3‐1), pronounced no obvious activity. Additionally, in silico predictions of physicochemical properties, ADME (absorption, distribution, metabolism and excretion) parameters, acute oral toxicity and indication of toxicity targets were performed for 1a and 2 in comparison with the antioxidant agent orsellinic acid.
Withanolides from the whole plant of Physalis angulata and their anti‐inflammatory activities
Authors: Yen Pham Hai , Cuong Le Canh Viet , Dat Ton That Huu , Thuy Dinh Thi Quy , Hoa Dang Thi Ngoc , Cuc Nguyen Thi , Yen Duong Thi Hai , Thao Do Thi , Anh Hoang Le Tuan 
Published: February 2020

AbstractFrom the dichloromethane extract of the whole plant of P. angulata growing in Vietnam, three withanolides including physagulin L (1), physagulin M (2), and withaminimin (3) were isolated by using various chromatography methods. Their chemical structures were determined by detailed analysis of 1D and 2D‐NMR data and comparison with reported data. All isolated compounds were tested for their inhibitory activities against NO production in LPS‐stimulated RAW 264.7 macrophages. The results showed that compound 3 had a weak anti‐inflammatory activity against NO production in RAW 264.7 macrophages with IC50 value of 69.6 ± 4.5 μM.
Effect of the incorporation of organoclay and melamine cyanurate on the flame retardancy and mechanical property of polyurethane foam
Authors: Nhung Hac Thi , Linh Pham Duy , Hanh Nguyen Thi , Nhan Nguyen Thanh , Oanh Ho Thi , Tuyen Nguyen Duc , Van Tuyen Nguyen , Ha Hoang Mai 
Published: February 2020

AbstractThe polyurethane composites were prepared by a one‐pot free‐rising method with Melamine cyanurate (MC) and Cloisite 20A additives. Flame‐retardant and mechanical properties of the foams were investigated. The vertical burning test showed that PUF composite loading 15 wt% MC was reached V0 classification of V‐rating. Limiting oxygen index (LOI) test revealed that the PU foam changed from an especially flammable material (LOI = 18.4 %) to a flame‐resistant material (LOI = 24.1 %) upon adding 25 wt% MC. However, the presence of MC reduced the compressive strength of the foam. In this report, we demonstrated the incorporation of organoclay and MC into PUF could improve the flame retardancy and the compressive strength of polyurethane foam.
Synthesis of platinum/reduced graphene oxide composite for cathode in dye‐sensitized solar cells
Authors: Thinh Nguyen Duc , Le Vo An , Nghia Le Tran Trung , Cuong Le Van , My Nguyen Thi Tra , Tuyet Nguyen Thi Kim , Hoang Nguyen Thai , Hieu Nguyen Huu 
Published: February 2020

AbstractPlatinum/reduced graphene oxide (Pt/rGO) composite materials with different mass ratios were fabricated by thermal decomposition method from H2PtCl6 and reduce graphene oxide (rGO) as precursors. Pt/rGO composites were used to fabricate Pt/rGO thin film cathodes by using the screen printing technology. The electrochemical properties of the fabricated cathodes were measured using the cyclic voltammetry method. Dye‐sensitized solar cells (DSSCs) were assembled from fabricated cathodes and were measured the performances by current density‐voltage (J‐V) curves and electrochemical impedance spectroscopy (EIS). The results showed the appropriate replacement amount rGO with Pt was 40 %, with the efficiency of 4.73 %, which was higher than that of commercial Pt cathode. The characterizations of the appropriate Pt/rGO composite were investigated by Fourier‐transform infrared spectroscopy (FTIR) and Raman spectroscopy. X‐ray diffraction (XRD) patterns indicated that the interlayer distance between the rGO was 0.35 nm while the transmission electron microscopy (TEM) image showed the Pt nanoparticles with size of 10‐20 nm were evenly distributed on the rGO sheets. These results indicated that Pt/rGO could be appropriated material to replace Pt in DSSCs to reduce the produce cost and enhance the efficiency.
Study on polarization of antimony lead electrode in gelled electrolyte
Authors: Binh Phan Thi , Van Anh Nguyen Thi , Thuy Mai Thi Thanh , Xuan Mai Thi 
Published: February 2020

AbstractGelled electrolyte is prepared from liquid glass and sulfuric acid with various specific weights in the presence of both gelling agents such as polyacrylamide and polyaniline. The antimony lead electrode is polarized by potentiodynamic method in gelled electrolyte compared with sulfuric acid solution (1.26 g/cm3). The results found that not only the overpotential of gas evolution but also the polarization resistance depends on sample preparation conditions. The concentration of PAM at 0.55 wt% contributed to the shift of overpotential of oxygen release in the more positive side but made decreasing the hydrogen escape overpotential compared with H2SO4 solution (1.26 g/cm3). It showed that the presence of PANi together with PAM did not improve the overpotential of oxygen release, but significantly inhibited the hydrogen evolution, although polarization resistance was approximately or smaller than that in H2SO4 solution (1.26 g/cm3).
In‐vitro DNA binding and antimicrobial studies of trivalent transition metal ion based macrocyclic complexes
Authors: Sangwan Vikas , Singh D. P. 
Published: February 2020

AbstractIn the current research work diaminotoluene based tetra‐azamacrocyclic‐14 membered [N4] macrocylic complexes of nitrate, chloride and acetate trivalent transition metals salts of Cr(III) and Fe(III) have been synthesized by taking the route of template methodology. The synthesized complexes were fully characterized by spectroscopic and physico‐analytical techniques like IR, ESI‐MS, ESR, Powder XRD, TGA, UV‐visible, magnetic moment, molar conductance, in addition to the elemental analysis measurements. The monomeric and electrolytic nature of the complexes is elucidated by the help of ESI‐MS and molar conductance values that reveals about the 1:2 electrolytic behaviour. On the basis of above analytical techniques the complexes may be empirically formulated as [MLX]X2 in which L is macrocyclic ligand obtained from the [2+2] condensation reaction of 3,4‐diaminotoluene (DAT) and dibenzoylmethane (DBM). The thermal data provides an indication towards the absence of water molecular and various decomposition steps in the complexes. Further the compounds were screened for their antimicrobial potency against few strains of bacteria and fungus and fair results were found from the above studies. In addition to these DNA binding activity was also performed in order to elucidate the mode of binding the newly synthesised complexes.
Antiproliferative activity of isolated compounds from Pinus dalatensis and Pinus krempfii on acute myeloid Leukemia cells
Authors: Sa Nguyen Hoang , Tam Nguyen Thanh , Quan Tran Duc , Anh Nguyen Thi Hoang , Linh Nguyen Thi Thuy , Nhung Le Thi Hong , Adorisio Sabrina , Delfino Domenico V , Van Sung Tran , Thuy Trinh Thi 
Published: February 2020

AbstractOur previous chemical constituent study of Pinus dalatensis and Pinus krempfii had identified six compounds 1‐6. The continuing investigation of biological activity of the conifer species led to discovery of the antiproliferative activity of all isolated compounds 1‐6 on acute myeloid leukemia cells as shown by the effects on cell cycle progression. Remarkably, compound 3 (chrysin) exibited potent bioactivity at the concentration of 10 μg/mL.
Molecular dynamics simulation of the interaction between human CD38 and some quinoline derivative inhibitors using reactive force field
Authors: Van Dang Ung 
Published: February 2020

AbstractThe paper presented initial calculated results obtained by molecular dynamics simulations of some CD38‐ micro and nanomolar inhibitor systems in vacuum using reactive force field ReaxFF. The ReaxFF software integrated in SCM's ADF has been used. The analysis and processing of results has been supplemented by VMD, CHIMERA and some external support softwares. The initial results showed that there are some associations between the inhibitor activity and the parameters compared apo and complex configurations. In particular, the higher the activity, the greater the difference in protein backbone RMSD between apo and complex. Nanomolar inhibitor molecules approached closer to the AC1 active site residues, especially GLU146 than micromolar one. In addition, the averaged and maximum fluctuation value of residues is also proportional to inhibitory activity. These can be considered suggestions for continuing to clarify the mechanism of CD38 inhibition of different ligand types supporting to the prediction and recommendation of new high active inhibitors
Modification of the vinylogous aldol condensation – Another approach to the synthesis of C(15)‐alkylidene and benzylidene andrographolide derivatives
Authors: Huy Ly Minh , Dung Huynh Ha Ngoc , Hy Nguyen Dinh , Trang Le Bao , Kien Duong Trung , Nghiem Tieu Uy , Van Anh Tran Thi , Tuyen Truong Ngoc 
Published: February 2020

AbstractA two‐step protocol for the synthesis of 15‐alkylidene and benzylidene derivatives of 14‐deoxy‐11,12‐didehydroandrographolide, which was conducted through a dehydration reaction of andrographolide and a vinylogous aldol condensation between α,β‐unsaturated butenolide moiety and benzaldehyde derivatives has been developed. Combining with various experiments on new catalysts for these reactions: the dehydration of andrographolide by concentrated H2SO4 and the vinylogous aldol reaction by K2CO3 in MeOH or a mixture of CH3COOH/pyrrolidine in MeOH, this research has determined the optimized conditions for those catalysts and the new approach to this aldol‐like reaction. All compounds synthesized were characterized by the analysis of IR, NMR, HRMS spectra.
Bioactive compounds from marine Streptomyces sp.: Structure identification and biological activities
Authors: Abd‐Ellatif Aya E. S. , Abdel‐Razek Ahmed S. , Hamed Abdelaaty , Soltan Maha M , Soliman Hesham S. M. , Shaaban Mohamed 
Published: February 2020

AbstractThe marine Iotrochoto purpurea derived Streptomyces sp. IOPU produced ten diverse bioactive compounds: hexahydro‐menaquinone MK‐9 (1), borrelidin (2), ferulic acid (3), N‐acetylanthranilic acid (4), uracil (5), uridine (6), thymidine (7), sitosteryl‐3β‐D‐glucoside, linoleic acid and methyl linoleate. Structures of the obtained compounds were assigned by NMR and mass spectrometric means. The cytotoxic and antimicrobial activities of the extract were visualized against KB‐3‐1 and KB‐V1 cell lines, and a set of microorganisms. Borrelidin (2), was the potentially active against the colorectal Caco‐2 and breast MCF‐7 subtypes, with IC50 5.3 μM and < 3.1 μM, respectively. The obtained compounds were investigated as antioxidant and antimicrobial agents.
Investigation of effect of polyethylene oxide on properties and morphology of polylactic acid/chitosan/quinine composites
Authors: Trang Nguyen Thi Thu , Chinh Nguyen Thuy , Mai Tran Thi , Trung Tran Huu , Hoang Thai 
Published: February 2020

AbstractPolylactic acid (PLA) and chitosan (CS) has been attracted by many researchers due to their good
adhesion, biodegradability and biocompatibility. Quinine has been used for the treatment of malaria. In this work, we used emulsion method to prepare polylactic acid/chitosan/quinine (PCQ) nanoparticles with polyethylene oxide (PEO) as a compatibilizer and emulsifier. The content of containing PEO was 3‐10 wt. % compared with the weight of PLA. These nanocomposites were characterized by Fourier transform infrared spectroscopy (FTIR), Differential scanning calorimetry (DSC), and field emission scanning electron microscopy (FESEM). The FTIR spectra of these nanoparticles show that PLA, CS and quinine are interact through the hydrogen bonding and dipolar‐dipolar interactions between C‐O, C=N, OH groups in quinine and C‐O, NH, OH groups in chitosan with C‐O, C=O, OH groups in PLA. The FESEM images of the nanoparticles with different PEO contents indicate that the nanoparticles have a spherical shape with the average particle size in the range of 80‐220 nm.