72 results on '"Tran-Duy, A"'
Search Results
2. Determination of Cobalt in Seawater Using Neutron Activation Analysis after Preconcentration by Adsorption onto γ-MnO2 Nanomaterial
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Van-Phuc Dinh, Ngoc-Chung Le, Ngoc-Tuan Nguyen, Quang-Thien Tran, Van-Dong Nguyen, Anh-Tuyen Luu, N. Quang Hung, Tran Duy Tap, and Thien-Hoang Ho
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Chemistry ,QD1-999 - Abstract
The γ-MnO2 nanomaterial has been used to adsorb cobalt in the seawater at Phan Thiet City, Binh Thuan Province, Vietnam. Its concentration is determined by using the neutron activation analysis (NAA) method at the Dalat nuclear research reactor. Factors affecting the uptake of cobalt on the γ-MnO2 material such as the pH, adsorption time, and initial cobalt(II) concentration are investigated. The irradiated experiment data are calculated using the K0-Dalat program. The results obtained show that the trace dissolved cobalt in Phan Thiet seawater is found equal to 0.25 ± 0.04 μg/L (n=5, P=95%) with the adsorption efficiency being higher than 95% (n=4, P=95%).
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- 2018
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3. Poly(dopamine) surface‐modified polyethylene separator with electrolyte‐philic characteristics for enhancing the performance of sodium‐ion batteries
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Bao Tran Duy Nguyen, Van-Chuong Ho, Hai Yen Nguyen Thi, Jeong F. Kim, and Junyoung Mun
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Materials science ,Renewable Energy, Sustainability and the Environment ,Sodium ,Surface modified ,Energy Engineering and Power Technology ,Sodium-ion battery ,chemistry.chemical_element ,Electrolyte ,Polyethylene ,chemistry.chemical_compound ,Fuel Technology ,Nuclear Energy and Engineering ,chemistry ,Chemical engineering ,Dopamine ,medicine ,medicine.drug ,Separator (electricity) - Published
- 2021
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4. Influence of two phosphate-potassium solubilizing bacterial species on biomass and nitrate concentration on mustard greens (Brassica juncea (L.) Czernjaew) cultivated on acid sulfate soils
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Cao Ngoc Diep and Tran Duy Phat
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biology ,Chemistry ,Brassica ,food and beverages ,engineering.material ,biology.organism_classification ,medicine.disease_cause ,Rhizobium leguminosarum ,food.food ,Mustard Greens ,chemistry.chemical_compound ,Horticulture ,food ,Nitrate ,medicine ,Nitrogen fixation ,engineering ,Acid sulfate soil ,Biomass yield ,Brassica juncea ,Nitrogen chemical fertilizer ,Nitrate in leaf ,P-K solubilizing bacteria ,Rhizobium ,Acinetobacter calcoaceticus ,Fertilizer - Abstract
Two field trials were conducted to determine the effect of P-K solubilizing bacteria and nitrogen chemical fertilizer on growth, yield and nitrate in leaf of mustard greensBrassica junceaL.) cultivated on acid sulfate soils. Eight P-K solubilizing bacterial strains composed of 3 strains ofAcinetobactercalcoaceticusand 5 strains ofRhizobiumsp., bacterial liquid were directly watered into plant at 3 stages [6, 12 and 21 days after planting] during vegetable cultivation, chemical fertilizer (60N – 40 P2O5– 20 K2O) and control (no-inoculation). The study revealed that eight P-K solubilizing bacterial strains have good characteristics as nitrogen fixation, phosphate and potassium solubilisation. Application of nitrogen chemical concentration, increasing nitrate concentration of leaf of mustard greens. Application of bacterial liquid withAcinetobacter calcoaceticusstrain NT4 andAcinetobacter calcoaceticusstrain NT30 strain,Rhizobium tropicistrain N18 andRhizobiumleguminosarumstrain K35 on mustard greens cultivated on acid sulfate soils (basal fertilizer: 40 P2O5– 20 K2O) was the best cultural practice because the this model not only supported the highest biomass, but also decreased nitrate concentration in leaf of mustard greens.
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- 2021
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5. Accurate evaluation of hydrogen crossover in water electrolysis systems for wetted membranes
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Kihyun Kim, Mijeong Kim, Sang Yong Nam, Hansol Ko, Bao Tran Duy Nguyen, SeungHwan Kim, and Jeong F. Kim
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Electrolysis ,Work (thermodynamics) ,Materials science ,Hydrogen ,Electrolysis of water ,Renewable Energy, Sustainability and the Environment ,Crossover ,Energy Engineering and Power Technology ,Thermodynamics ,chemistry.chemical_element ,02 engineering and technology ,Permeation ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,01 natural sciences ,0104 chemical sciences ,law.invention ,chemistry.chemical_compound ,Fuel Technology ,Membrane ,chemistry ,law ,Nafion ,0210 nano-technology - Abstract
In fuel cell and electrolysis systems, hydrogen crossover is a phenomenon where hydrogen molecules (H2) permeate through a membrane, lowering the overall process efficiency and generating a potential safety risk. Many works have been reported to mitigate this undesired phenomenon, but it is yet difficult to accurately measure the rate of hydrogen crossover, particularly when the membrane is fully wetted in water. In this work, we investigated the pressure decay method as a simple, convenient, and low-cost method to characterize hydrogen crossover through wetted membranes for water electrolysis systems. Three different ion exchange membranes were analyzed: Nafion 212, Nafion 115, and in-house sulfonated poly(arylene ether sulfone). We rigorously confirmed our method and data by comparing it to the ANSI dataset with the current state-of-the-art equations of state (EOS) to account for the nonideality of high pressure hydrogen systems. The error from the gas non-ideality was less than 0.03%. As expected, the rate of hydrogen crossover showed high dependency on the temperature; more importantly, hydrogen crossover increased significantly when the membrane was fully soaked in water. For dry membranes, the proposed pressure decay method corroborated well with the literature data measured using other known methods. Moreover, for wetted membranes, the obtained data showed high similarity compared to the GC method which is currently the most reliable method in the literature. We attempted to predict the hydrogen permeability of wetted membranes using the solution diffusion model. The model based on the given thermodynamic parameters overestimated the hydrogen permeability, which can be used to estimate the ion channel tortuosity.
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- 2021
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6. Methylene blue adsorption mechanism of activated carbon synthesised from cashew nut shells
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Tran Duy Hai, Phan Dinh Tuan, Dinh Sy Khang, Nguyen Hoc Thang, and Dinh Thi Nga
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Pollutant ,Chemistry ,General Chemical Engineering ,Thermal decomposition ,chemistry.chemical_element ,General Chemistry ,Raw material ,Atmospheric temperature range ,chemistry.chemical_compound ,Adsorption ,Chemical engineering ,medicine ,Carbon ,Methylene blue ,Activated carbon ,medicine.drug - Abstract
Activated carbon produced from agricultural products and wastes has been applied widely to remove pollutants in the field of waste water treatment. However, the cost of this adsorbent depends so much on the raw material sources. Therefore, the approach of producing activated carbon from agricultural waste is strongly recommended due to economic advantages and environmental protection. One of the potential feed-stocks for the activated carbon production is cashew nut shell (CNS) waste which could reduce the negative impacts to the environment from the cashew nut processing industry and simultaneously enhance the values of the related products. This study focused on evaluating the influences of variable factors, such as activation temperature and time, on the properties of the activated carbon obtained from CNS. Methylene blue (MB) adsorption was applied to understand the adsorption mechanism of the products. The results show that increasing the activation temperature led to a rise in the adsorption capacity of the activated carbon within the temperature range of 800 to 850 °C. Otherwise, the values were reduced when the temperature was greater than 850 °C and this was related to the thermal decomposition of carbon. The adsorption capacity also increased when the activation time was changed from 30 min to 50 min. However, in the activation time range from 50 to 70 min, there was a reduction of the adsorption capacity of CNS-based activated carbon. The results also show that the MB adsorption of the activated carbon occurred with one-site-occupancy in the first layer and then layer-by-layer adsorption formation.
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- 2021
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7. Identification and Structural Characterization of Anti-Endoplasmic Reticulum Stress Compounds from Ageratum conyzoides (L.)
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Kenji Kanaori, Ako Nakagami, Yen D H Nguyen, Kaeko Kamei, Thanh Nguyen, Tran Duy Binh, Cuong C. Nguyen, Tuan L. A. Pham, Ryo Kusunoki, and Le Van Vang
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Pharmacology ,biology ,Biochemistry ,Chemistry ,Endoplasmic reticulum ,Ageratum conyzoides ,Organic Chemistry ,Drug Discovery ,Identification (biology) ,Plant Science ,biology.organism_classification - Abstract
Ageratum conyzoides is an herbaceous plant widely used in traditional medicine against various diseases, and possesses anti-inflammatory, anti-ulcer, analgesic, and diuretic properties. However, its effects on endoplasmic reticulum (ER) stress, as observed in diseases such as diabetes, have not yet been characterized. In this study, using mouse pancreatic Beta-cells, we demonstrated that the ethanol extract of A. conyzoides effectively suppressed cell death induced by ER stress. Four polymethoxyflavones (PMFs) including (1) 5,6,7,3′,4′,5′- hexamethoxyflavone; (2) 5,6,7,8,3′,4′-hexamethoxyflavone (nobiletin); (3) 3′,4′-methylenedioxy-5′,5,6,7- tetramethoxyflavone; and (4) 5,6,7,8,5′-pentamethoxy-3′,4′-methylenedioxyflavone were isolated from the ethyl acetate fraction using reverse-phase chromatography. Their structures were elucidated using spectroscopic and mass-spectrometric analyses including 1D-, 2D-NMR, and HRESI-MS. All compounds were further evaluated for their ability to inhibit ER stress. Our results suggested that only compound 1 did not show an ability to rescue ER stress-induced cell death. Additionally, compound 2 as a nobiletin and its commercial product alleviated the tunicamycin-dependent chop mRNA expression induction. Notably, extremely low concentrations of both compounds exerted cytoprotective activity against tunicamycin-induced ER stress in pancreatic Beta-cells
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- 2020
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8. Dialkyl imidazolium acetate ionosilica as efficient and recyclable organocatalyst for cyanosilylation reactions of ketones
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Peter Hesemann, Alysson Duarte Rodrigues, Giang Vo-Thanh, Thanh Tran Duy, Institut Charles Gerhardt Montpellier - Institut de Chimie Moléculaire et des Matériaux de Montpellier (ICGM ICMMM), Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-Université Montpellier 1 (UM1)-Université Montpellier 2 - Sciences et Techniques (UM2)-Institut de Chimie du CNRS (INC), Institut de Chimie Moléculaire et des Matériaux d'Orsay (ICMMO), Institut de Chimie du CNRS (INC)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), and Université Paris-Sud - Paris 11 (UP11)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)
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Cyanosilylation ,Iodide ,Ion chromatography ,lcsh:TJ807-830 ,lcsh:Renewable energy sources ,02 engineering and technology ,010402 general chemistry ,01 natural sciences ,Catalysis ,chemistry.chemical_compound ,Deprotonation ,lcsh:QH540-549.5 ,Organic chemistry ,[CHIM]Chemical Sciences ,N-heterocyclic carbenes ,Trimethylsilyl cyanide ,Heterogeneous organocatalysis ,chemistry.chemical_classification ,Ion exchange ,Renewable Energy, Sustainability and the Environment ,Ionosilica ,021001 nanoscience & nanotechnology ,0104 chemical sciences ,Ionic liquids ,chemistry ,Ionic liquid ,lcsh:Ecology ,0210 nano-technology ,Carbene - Abstract
International audience; We report new heterogeneous organocatalyst based on silica hybrid supported N-heterocyclic carbene (NHC-) species. The organocatalyst is formed from an imidazolium iodide based ionosilica material, followed by iodide/acetate anion exchange. The imidazolium acetate generates the organocatalytic carbene via partial deprotonation of the imidazolium ring in situ. As monitored via EDX, solid state NMR and ion chromatography measurements, the iodide/acetate exchange involving the imidazolium ionosilica material took place only in small extent. Despite the fact that the exchanged material contains only a very small amount of acetate, we observed good catalytic activity and recyclability in cyanosilylation reactions of ketones with trimethylsilyl cyanide. The versatility of the catalyst was highlighted via reaction with several substrates, yielding the corresponding cyanohydrins in good yields. In recycling experiments, the material showed decreasing catalytic activity starting from the third reaction cycle, but high catalytic activity can be regenerated via another acetate treatment. Our work is important as it highlights the possibility to combine carbene chemistry and silica, which are antagonistic at a first glance. We show that imidazolium acetate based ionosilicas are therefore heterogeneous 'proto-carbenes', and that there is no need to form strongly basic silica supported NHCs to obtain heterogeneous NHC-organocatalysts. This work therefore opens the route towards heterogeneous and re-usable NHC-organocatalysts from supported ionic liquid imidazolium acetates.
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- 2020
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9. Extraction of High Crystalline Nanocellulose from Biorenewable Sources of Vietnamese Agricultural Wastes
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Tran Duy Tap, Le Van Hieu, Ha Thuc Chi Nhan, Vu Nang An, Tran Thi Van, and Pham Van Viet
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Environmental Engineering ,Materials science ,Polymers and Plastics ,02 engineering and technology ,021001 nanoscience & nanotechnology ,Husk ,Nanocellulose ,Hydrolysis ,chemistry.chemical_compound ,Crystallinity ,020401 chemical engineering ,chemistry ,Chemical engineering ,Sodium hydroxide ,Materials Chemistry ,Lignin ,Thermal stability ,Fiber ,0204 chemical engineering ,0210 nano-technology - Abstract
Cellulose nanocrystals (CNCs) is one of the interesting materials attracting many researchers from the decades, especially when they are extracted from natural biomass resources. This study focuses on the isolation of CNCs with high crystallinity from Vietnamese agricultural wastes (Nypa Fruticans trunk, coconut husk fiber, and rice husk). CNCs were extracted from the above natural sources by a three-step process including formic/peroxyformic acid pre-treatment, hydrogen peroxide/sodium hydroxide treatment, and a hydrolysis disintegration process. The structure and thermal property of obtained materials after each stage of treatments were characterized by XRD, TGA, TEM, and FT-IR analysis. TEM observation has showed the CNCs with high aspect ratio in shape of 200–500 nm in length and 10–15 nm in width. FT-IR results indicated that lignin was completely removed from the samples during chemical treatment. The high crystalline index (nearly 80%) and improved thermal stability of the CNCs nanofibers indicate its various potential applications.
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- 2020
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10. Sustainable Fabrication of Organic Solvent Nanofiltration Membranes
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Jeong F. Kim, Bao Tran Duy Nguyen, and Hai Yen Nguyen Thi
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bio-based polymers ,Fabrication ,Materials science ,environmental-friendly polymers ,Filtration and Separation ,Nanotechnology ,Review ,02 engineering and technology ,010402 general chemistry ,organic solvent nanofiltration ,lcsh:Chemical technology ,01 natural sciences ,parasitic diseases ,Chemical Engineering (miscellaneous) ,lcsh:TP1-1185 ,lcsh:Chemical engineering ,green solvents ,Material recycling ,chemistry.chemical_classification ,Process Chemistry and Technology ,Organic solvent ,technology, industry, and agriculture ,lcsh:TP155-156 ,Polymer ,021001 nanoscience & nanotechnology ,sustainability ,Interfacial polymerization ,0104 chemical sciences ,Waste generation ,Membrane ,chemistry ,Nanofiltration ,0210 nano-technology - Abstract
Organic solvent nanofiltration (OSN) has been considered as one of the key technologies to improve the sustainability of separation processes. Recently, apart from enhancing the membrane performance, greener fabricate on of OSN membranes has been set as a strategic objective. Considerable efforts have been made aiming to improve the sustainability in membrane fabrication, such as replacing membrane materials with biodegradable alternatives, substituting toxic solvents with greener solvents, and minimizing waste generation with material recycling. In addition, new promising fabrication and post-modification methods of solvent-stable membranes have been developed exploiting the concept of interpenetrating polymer networks, spray coating, and facile interfacial polymerization. This review compiles the recent progress and advances for sustainable fabrication in the field of polymeric OSN membranes.
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- 2021
11. Investigation of the Lamellar Grains of Graft-type Polymer Electrolyte Membranes for Hydrogen Fuel Cell Application using Ultrasmall-angle X-ray Scattering
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Tran Thanh Danh, Huynh Truc Phuong, Tran Hoang Long, Dang Van Hoa, Le Quang Luan, Tran Van Man, Tran Duy Tap, Lam Hoang Hao, Pham Thi Thu Hong, and Dinh Tran Trong Hieu
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chemistry.chemical_classification ,Membrane ,Materials science ,chemistry ,Chemical engineering ,Scattering ,X-ray ,Hydrogen fuel cell ,Lamellar structure ,Polymer ,Electrolyte ,Graft Type - Abstract
The extensive ultrasmall-angle X-ray scattering measurements are performed in order to investigate the changes of lamellar grains of poly(styrenesulfonic acid)-grafted poly(ethylene-co-tetrafluoroethylene) polymer electrolyte membranes (ETFE-PEMs) that occur during the alteration of grafting degree (GD) under dry and immersed conditions. The lamellar grains of three series of the samples (polystyrene-grafted ETFE films and dry and hydrated ETFE-PEMs) are formed during the grafting process and develop independently with the change of the lamellar stacks. Interestingly, three series of samples exhibit a very similar trend of lamellar grain at any GD and a significant amount of graft chains is observed directly in the region between the grains (GD £ 59%) and outside of the grain network structures (GD > 59%). This observation indicates: i) The formation of the lamellar grains; ii) The rapid changes in characteristic sizes of the lamellar grains compared with the lamellar stacks; and iii) The newly generated phases consisting of only the graft materials. These findings explain why the lamellar grains and the graft chains play an important role in the higher proton conductivity and compatible tensile strengths of the membranes, compared with Nafion, at the immersed and severe operating conditions.
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- 2021
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12. Binding free energy of protein/ligand complexes calculated using dissociation Parallel Cascade Selection Molecular Dynamics and Markov state model
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Hata, Hiroaki, Tran, Phuoc Duy, Tran, Duy Phuoc, SOBEH, Mohamed Marzouk, and Kitao, Akio
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pacs-md ,binding free energy calculation ,Markov chain ,QH301-705.5 ,Physiology ,Chemistry ,Physics ,QC1-999 ,Intermolecular force ,enhanced sampling method ,General Medicine ,Ligand (biochemistry) ,Molecular dynamics ,molecular dynamics simulation ,FKBP ,Computational chemistry ,Cascade ,markov state model ,QP1-981 ,Molecule ,Biology (General) ,Protein ligand - Abstract
We recently proposed a computational procedure to simulate the dissociation of protein/ligand complexes using the dissociation Parallel Cascade Selection Molecular Dynamics simulation (dPaCS-MD) method and to analyze the generated trajectories using the Markov state model (MSM). This procedure, called dPaCS-MD/MSM, enables calculation of the dissociation free energy profile and the standard binding free energy. To examine whether this method can reproduce experimentally determined binding free energies for a variety of systems, we used it to investigate the dissociation of three protein/ligand complexes: trypsin/benzamine, FKBP/FK506, and adenosine A2A receptor/T4E. First, dPaCS-MD generated multiple dissociation pathways within a reasonable computational time for all the complexes, although the complexes differed significantly in the size of the molecules and in intermolecular interactions. Subsequent MSM analyses produced free energy profiles for the dissociations, which provided insights into how each ligand dissociates from the protein. The standard binding free energies obtained by dPaCS-MD/MSM are in good agreement with experimental values for all the complexes. We conclude that dPaCS-MD/MSM can accurately calculate the binding free energies of these complexes.
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- 2021
13. Hydrolysis Methods for Protein Extraction from Seafood
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Tran Duy Hai
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Hydrolysis ,Chromatography ,Chemistry ,Protein purification ,General Earth and Planetary Sciences ,General Environmental Science - Published
- 2020
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14. Purification of titanium tetrachloride from titania slag chlorination
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Ly Cam Hung, Phan Dinh Tuan, Tran Duy Hai, Le Minh Vien, and Tran Anh Khoa
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chemistry.chemical_compound ,Chemistry ,visual_art ,Metallurgy ,visual_art.visual_art_medium ,Titanium tetrachloride ,Slag ,Life satisfaction - Published
- 2019
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15. Isolation and characterization of six flavonoids from the leaves of Sterculia foetida Linn
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Pham Dinh Thuong, Mai Dinh Tri, Nguyen Tan Phat, Nguyen Trung Duan, Ha Tuan Dat, Doan Tran Duy Cuong, Nguyen Thi Hoa, Dang Van Son, Pham Nguyen Kim Tuyen, and Nguyen Kim Phi Phung
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chemistry.chemical_classification ,Traditional medicine ,Chemistry ,Sterculia foetida ,ved/biology ,ved/biology.organism_classification_rank.species ,Flavonoid ,Flavan-3-ol ,Isolation (microbiology) - Published
- 2019
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16. Study on total lipid content, lipid class composition of some fire and soft corals collected in Nha Trang, Vietnam
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Pham Quoc Long, Dang Thi Minh Nguyet, Luu Van Huyen, Nguyen Thanh Vinh, Tran Duy Phong, Trinh Thi Huong, Nguyen Ba Kien, Dang Thi Phuong Ly, and Nguyen Thi Nga
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Chemistry ,Lipid content ,Composition (visual arts) ,Food science ,Class (biology) - Abstract
For the first time, the total lipid content and lipid class composition of the Vietnamese soft corals (Sinularia brassica, Sinularia flexibilis) and fire corals (Millepora dichotoma, Millepora platyphylla) were investigated. The results indicated that the total lipid content of the investigated species was significantly different. Compositions of the lipid classes were analyzed using TLC and image analysis program Sorbfil TLC Videodensitometer DV and the results showed that phospholipids (PL, 10.91–16.02%), monoalkyldiacylglycerols (MADAG, 20.69-39.92%) and hydrocarbon wax (HW, 29.83-37.17%) were the main lipid classes of the total lipid in soft coral species. Meanwhile, PL (24.11-33.23%), TG (14.27–34.92%), ST (10.10–14.50%) and HW (12.08–19.95%) were predominant in fire coral species. ST, TG and FFA contents in soft and fire corals were at low level. DG was only present in the Sinularia flexibilis but not in other studied corals.
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- 2019
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17. Blood Oxygenation Using Fluoropolymer-Based Artificial Lung Membranes
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Eunsung Yi, You In Park, Jeong F. Kim, Bao Tran Duy Nguyen, Dongje Han, Yejin Song, Eun-Ho Sohn, Park Ahrumi, Jun Tae Jung, Young Moo Lee, and Young Hoon Cho
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Materials science ,Low protein ,Biocompatibility ,0206 medical engineering ,Biomedical Engineering ,02 engineering and technology ,Artificial lung ,Biomaterials ,Contact angle ,chemistry.chemical_compound ,Animals ,Humans ,Phase inversion (chemistry) ,Lung ,Membranes ,Sheep ,Membranes, Artificial ,021001 nanoscience & nanotechnology ,020601 biomedical engineering ,Membrane ,chemistry ,Chemical engineering ,Fluoropolymer ,Polyvinyls ,Adsorption ,0210 nano-technology ,Protein adsorption - Abstract
Artificial lung (AL) membranes are used for blood oxygenation for patients undergoing open-heart surgery or acute lung failures. Current AL technology employs polypropylene and polymethylpentene membranes. Although effective, these membranes suffer from low biocompatibility, leading to undesired blood coagulation and hemolysis over a long term. In this work, we propose a new generation of AL membranes based on amphiphobic fluoropolymers. We employed poly(vinylidene-co-hexafluoropropylene), or PVDF-co-HFP, to fabricate macrovoid-free membranes with an optimal pore size range of 30-50 nm. The phase inversion behavior of PVDF-co-HFP was investigated in detail for structural optimization. To improve the wetting stability of the membranes, the fabricated membranes were coated using Hyflon AD60X, a type of fluoropolymer with an extremely low surface energy. Hyflon-coated materials displayed very low protein adsorption and a high contact angle for both water and blood. In the hydrophobic spectrum, the data showed an inverse relationship between the surface free energy and protein adsorption, suggesting an appropriate direction with respect to biocompatibility for AL research. The blood oxygenation performance was assessed using animal sheep blood, and the fabricated fluoropolymer membranes showed competitive performance to that of commercial polyolefin membranes without any detectable hemolysis. The data also confirmed that the bottleneck in the blood oxygenation performance was not the membrane permeance but rather the rate of mass transfer in the blood phase, highlighting the importance of efficient module design.
- Published
- 2021
18. Stercufoetin A, new oleanane-type triterpenoid from the leaves of Sterculia foetida L
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Nguyen Minh An Tran, Dinh Tri Mai, Trung Duan Nguyen, Trong D. Tran, Tan Phat Nguyen, Tran Duy Cuong Doan, Tuan Dat Ha, and Nguyen Kim Tuyen Pham
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Sterculiaceae ,biology ,Traditional medicine ,010405 organic chemistry ,Chemistry ,Sterculia foetida ,ved/biology ,Organic Chemistry ,ved/biology.organism_classification_rank.species ,Plant Science ,biology.organism_classification ,01 natural sciences ,Biochemistry ,0104 chemical sciences ,Analytical Chemistry ,HeLa ,010404 medicinal & biomolecular chemistry ,chemistry.chemical_compound ,Triterpenoid ,Maslinic acid ,Cell culture ,Oleanane ,Oleanolic acid - Abstract
From the leaves of Sterculia foetida L., one new oleanane-type triterpenoid, named stercufoetin A (1) together with four known ones, vergatic acid (2), β-amyrin (3), oleanolic acid (4) and maslinic acid (5) were purified by diversely chromatographic methods. Their structures were proposed by HR-APCI-MS and NMR experiments. Compounds (2–5) were notified for the first time from this species. Compound 1 showed weak cytotoxic effect against three human cancer cell lines (MCF-7, HepG2 and HeLa) using SRB assay.
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- 2021
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19. The Insecticidal Capacity of Ethanol Extract from Cascabela Peruviana (L.) Lippold Against Fruit Fly
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Tran Thi Tu Ai, Nguyen Van Ay, Huynh Hong Phien, Tran Thanh Men, Nguyen Thi Kim Hue, Tran Duy Binh, and Do Tan Khang
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chemistry.chemical_classification ,History ,Ethanol ,Cascabela ,food.ingredient ,Polymers and Plastics ,Traditional medicine ,Chemistry ,Flavonoid ,Industrial and Manufacturing Engineering ,chemistry.chemical_compound ,food ,Polyphenol ,Business and International Management - Published
- 2021
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20. Effects of Launaea sarmentosa Extract on Lipopolysaccharide-Induced Inflammation via Suppression of NF-κB/MAPK Signaling and Nrf2 Activation
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Trong Tuan Nguyen, Tran Duy Binh, Ryo Kusunoki, Kaeko Kamei, Yen D H Nguyen, Tuan L. A. Pham, Thanh Q C Nguyen, and Kenji Kanaori
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0301 basic medicine ,inflammatory cytokine ,antioxidant ,lcsh:TX341-641 ,Inflammation ,Pharmacology ,medicine.disease_cause ,Proinflammatory cytokine ,03 medical and health sciences ,chemistry.chemical_compound ,0302 clinical medicine ,medicine ,oxidative stress ,Protein kinase A ,Protein kinase B ,Nutrition and Dietetics ,Launaea sarmentosa ,biology ,NF-κB ,biology.organism_classification ,macrophages ,030104 developmental biology ,chemistry ,030220 oncology & carcinogenesis ,endoplasmic reticulum stress ,Tumor necrosis factor alpha ,medicine.symptom ,lcsh:Nutrition. Foods and food supply ,Oxidative stress ,Food Science - Abstract
Launaea sarmentosa has been extensively used as a nutrient herb in traditional Vietnamese remedies for the treatment of various diseases, especially inflammatory diseases. However, no detailed research has been conducted examining the molecular mechanisms involved in the suppression of inflammatory response. Here, we studied the effects of L. sarmentosa methanol extract on lipopolysaccharide (LPS)-induced inflammation using RAW 264.7 macrophages. The extract demonstrated potent antioxidant activity owing to the presence of polyphenolic and flavonoid components. Pretreatment with the extract inhibited LPS-mediated secretion of nitric oxide, reactive oxygen species, and tumor necrosis factor-&alpha, as well as the expression of inflammatory cytokines. Furthermore, the activation of the nuclear factor-kappa B pathway and phosphoinositide-3-kinase/protein kinase B pathways was blocked by the extract by inhibiting Akt phosphorylation. Additionally, the mitogen-activated protein kinase pathway was suppressed, and endoplasmic reticulum stress was attenuated. Furthermore, the extract promoted the activity of nuclear factor erythroid-2-related factor 2 resulting in the up-regulation of heme oxygenase-1 pathway, leading to the suppression of oxidative stress and inflammatory response. Taken together, the results indicate that L. sarmentosa exhibits anti-inflammatory effects, and hence, can be further developed as a novel drug for the treatment of diseases associated with excessive inflammation.
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- 2020
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21. Anti-Inflammatory Effects of Lasia spinosa Leaf Extract in Lipopolysaccharide-Induced RAW 264.7 Macrophages
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Yen D H Nguyen, Kenji Kanaori, Thanh Q C Nguyen, Kaeko Kamei, Tuan L. A. Pham, Dai Thi Xuan Trang, Tran Duy Binh, and Trong Tuan Nguyen
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Lipopolysaccharides ,Lipopolysaccharide ,medicine.drug_class ,inflammatory cytokines ,Inflammation ,Pharmacology ,medicine.disease_cause ,Catalysis ,Anti-inflammatory ,Article ,Nitric oxide ,Proinflammatory cytokine ,lcsh:Chemistry ,Inorganic Chemistry ,chemistry.chemical_compound ,Mice ,medicine ,Animals ,Araceae ,Humans ,Lasia spinosa ,Physical and Theoretical Chemistry ,lcsh:QH301-705.5 ,Molecular Biology ,Protein kinase B ,Spectroscopy ,anti-inflammatory ,Chemistry ,Plant Extracts ,anti-oxidant ,Macrophages ,Organic Chemistry ,NF-kappa B ,General Medicine ,Computer Science Applications ,Plant Leaves ,IκBα ,RAW 264.7 Cells ,lcsh:Biology (General) ,lcsh:QD1-999 ,medicine.symptom ,Oxidative stress ,Signal Transduction - Abstract
Lasia spinosa (L.) Thwaites was used as a traditional medicine to treat many inflammatory diseases for centuries. However, its effects on the inflammatory response are not yet characterized. In this study, we investigated the anti-inflammatory activities of L. spinosa leaf extract in lipopolysaccharide (LPS)-induced RAW 264.7 macrophages. We found that ethanol extracts of L. spinosa leaves showed anti-oxidant activity due to the presence of high levels of polyphenolic compounds. Treatment with the leaf extract significantly repressed the production of inflammatory mediators such as nitric oxide and reactive oxygen species and the expression of pro-inflammatory cytokines in the LPS-stimulated RAW 264.7 cells. Moreover, L. spinosa leaf extract treatment prevented activation of the nuclear factor-kappa B pathway by inhibiting nuclear factor of kappa light polypeptide gene enhancer in B-cells inhibitor, alpha (I&kappa, B&alpha, ) degradation. Furthermore, the mitogen-activated kinase and phosphoinositide-3-kinase/protein kinase B (PI3K/Akt) pathways were suppressed upon treatment with the leaf extract. In addition to suppressing inflammatory factors, the extract also activated the nuclear factor erythroid 2-related factor 2/heme-oxygenase-1 pathway. We propose that L. spinosa leaf extract has the potential as an effective therapeutic agent for alleviating oxidative stress and excessive inflammation.
- Published
- 2020
22. Highly efficient electrocatalyst of N-doped graphene-encapsulated cobalt-iron carbides towards oxygen reduction reaction
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Nam Hoon Kim, Joong Hee Lee, Tran Duy Thanh, Jagadis Gautam, and Kakali Maiti
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inorganic chemicals ,Materials science ,chemistry.chemical_element ,Nanoparticle ,02 engineering and technology ,General Chemistry ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Electrocatalyst ,01 natural sciences ,0104 chemical sciences ,Catalysis ,Carbide ,chemistry.chemical_compound ,Transition metal ,Chemical engineering ,chemistry ,General Materials Science ,Methanol ,0210 nano-technology ,Mesoporous material ,Cobalt - Abstract
Development of highly functional and durable catalysts in a cost-effective way is a promising approach for practical energy conversion applications. In this study, a novel catalyst, cobalt iron carbide nanoparticles encapsulated by nitrogen doped graphene nanosheets, is successfully synthesized through a simple refluxing strategy followed by a post annealing process. It is found that the catalyst exhibits excellent catalytic activity for oxygen reduction reaction in alkaline medium. The oxygen reduction reaction kinetics of the catalyst mainly follow a 4-electron transferred pathway along with good diffusion limit current density, highly positive onset potential (−0.04 V) and half-wave potential (−0.11 V). In addition to catalytic activity, the catalyst demonstrates advanced superior stability, and excellent methanol tolerance in comparison with commercial platinum catalyst. The impressive catalytic performance of the catalyst is attributed to the unique mesoporous metal-core/graphene-shell architecture in which high interactions between two transition metals and transition metal-carbon synergistically provide enhanced catalytically active sites, accelerate interfacial charge transfer, and optimize oxygen adsorption energy. The results demonstrate that such catalyst can be an alternative low-cost and efficient catalyst for oxygen reduction reaction in energy conversion applications.
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- 2018
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23. Humidity and temperature effects on mechanical properties and conductivity of graft-type polymer electrolyte membrane
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La Ly Nguyen, Do Duy Khiem, Tran Duy Tap, Shin Hasegawa, Yasunari Maekawa, Shin-ichi Sawada, Le Quang Luan, Nguyen Quoc Hien, and Phan Bach Thang
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chemistry.chemical_classification ,Radiation ,Materials science ,Proton exchange membrane fuel cell ,02 engineering and technology ,Polymer ,Electrolyte ,Conductivity ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,chemistry.chemical_compound ,ETFE ,Membrane ,chemistry ,Chemical engineering ,Ultimate tensile strength ,Relative humidity ,0210 nano-technology - Abstract
The relative humidity (RH) and temperature dependence of the conductance and mechanical properties of poly(styrenesulfonic acid) (PSSA)-grafted poly(ethylene-co-tetrafluoroethylene) polymer electrolyte membrane (ETFE-PEM) at a grafting degree (GD) of 36%, corresponding to an ion exchange capacity (IEC) of 2.03 mmol/g with Nafion-212 as a reference, were investigated. The activation energy of ETFE-PEM was 8.2 kJ/mol, which is lower than that of Nafion-212 (13.2 kJ/mol). The tensile strength of ETFE-PEM (12 − 34 MPa) is higher than that of Nafion-212 (10 − 25 MPa) under dry, wet, or humidified conditions (at 0% and 98% RH at 80 °C). The excellent mechanical properties of ETFE-PEM under humidified conditions can be explained by partial or total compensation effects between PSSA grafts containing water and the ETFE backbone and hierarchical crystalline structures of the membrane. The pristine ETFE, grafted-ETFE, and ETFE-PEM exhibited crystallinities of 30.3%, 22.4%, and 14.6% according to X-ray diffraction results. Thus, sulfonation strongly altered the natural crystalline structures of the pristine ETFE film. Additionally, the 112 XRD reflections played an essential role in the crystalline properties, which determined the mechanical strength of the membrane. The results indicate that ETFE-PEM with an IEC of 2.03 mmol/g exhibited promising electrochemical and mechanical properties under moderately severe operating conditions for fuel cell applications.
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- 2018
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24. Hierarchical Heterostructures of Ultrasmall Fe2O3-Encapsulated MoS2/N-Graphene as an Effective Catalyst for Oxygen Reduction Reaction
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Nam Hoon Kim, Nguyen Dinh Chuong, Joong Hee Lee, and Tran Duy Thanh
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Materials science ,Graphene ,Kinetics ,Nanoparticle ,chemistry.chemical_element ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Electrocatalyst ,01 natural sciences ,Decomposition ,Oxygen ,0104 chemical sciences ,Catalysis ,law.invention ,chemistry.chemical_compound ,chemistry ,Chemical engineering ,law ,General Materials Science ,0210 nano-technology ,Molybdenum disulfide - Abstract
In this study, a facile approach has been successfully applied to synthesize a hierarchical three-dimensional architecture of ultrasmall hematite nanoparticles homogeneously encapsulated in MoS2/nitrogen-doped graphene nanosheets, as a novel non-Pt cathodic catalyst for oxygen reduction reaction in fuel cell applications. The intrinsic topological characteristics along with unique physicochemical properties allowed this catalyst to facilitate oxygen adsorption and sped up the reduction kinetics through fast heterogeneous decomposition of oxygen to final products. As a result, the catalyst exhibited outstanding catalytic performance with a high electron-transfer number of 3.91–3.96, which was comparable to that of the Pt/C product. Furthermore, its working stability with a retention of 96.1% after 30 000 s and excellent alcohol tolerance were found to be significantly better than those for the Pt/C product. This hybrid can be considered as a highly potential non-Pt catalyst for practical oxygen reduction r...
- Published
- 2018
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25. Comparative Analysis on Blossom-end Rot Incidence in Two Tomato Cultivars in Relation to Calcium Nutrition and Fruit Growth
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Mitsuo Ooyama, Tran Duy Vinh, Tanjuro Goto, Yuichi Yoshida, Yoshiyuki Tanaka, and Ken-ichiro Yasuba
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0106 biological sciences ,Incidence (epidemiology) ,chemistry.chemical_element ,04 agricultural and veterinary sciences ,Plant Science ,Horticulture ,Biology ,Calcium ,Hydroponics ,01 natural sciences ,040501 horticulture ,Agronomy ,chemistry ,Cultivar ,0405 other agricultural sciences ,010606 plant biology & botany - Published
- 2018
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26. Isolation and Identification of Antibacterial and Antifungal Compounds from Praxelis clematidea R. M. King & H. Robinson as an Effective Potential Treatment against Rice Pathogens
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Tran Duy Binh, Cuong C. Nguyen, Thanh Nguyen, Kenji Kanaori, Kaeko Kamei, and Le Van Vang
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Pyricularia ,Chloroform ,Chromatography ,plant extracts ,biology ,alternative antimicrobials ,Praxelis clematidea ,Ethyl acetate ,food and beverages ,Agriculture ,Xanthomonas oryzae pv. oryzae ,Pyricularia oryzae ,natural antimicrobials ,4,4′,4″-nitrilotriphenol ,Antimicrobial ,biology.organism_classification ,chemistry.chemical_compound ,Xanthomonas oryzae ,chemistry ,Antibacterial activity ,Agronomy and Crop Science ,Bacteria - Abstract
Bacterial leaf blight and blast diseases caused by the bacterium Xanthomonas oryzae pv. oryzae and the fungus Pyricularia oryzae, respectively, are among the most important infectious diseases affecting rice. We evaluated the antimicrobial effects of compounds derived from Praxelis clematidea on Xanthomonas oryzae and Pyricularia oryzae. The dried aerial parts of Praxelis clematidea were subjected to ethanol extraction, separated by solvent partitioning using hexane, chloroform, ethyl acetate, and water. In vitro assays demonstrated that the main antibacterial and antifungal activities were distributed in the ethyl acetate and chloroform fractions, respectively. These fractions were further separated using silica gel chromatography and reversed-phase chromatography. Finally, we isolated five compounds, 1–5, that inhibited the growth of Xanthomonas oryzae in vitro and four compounds, 6–9, that exhibited in vitro antifungal activity against Pyricularia oryzae. We evaluated their antimicrobial activities and identified their chemical structures by NMR and mass spectrometry analyses. This is the first study to isolate compound 2 (4,4′,4″-nitrilotriphenol) as an alternative microbial from natural resources and evaluate its physiological activity. Moreover, this is the first report to demonstrate antibacterial activity in comparison with flavonoids. Praxelis clematidea extracts plausibly exert both antibacterial and antifungal effects, which should be further validated in field trials.
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- 2021
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27. Morphological characterization of grafted polymer electrolyte membranes at a surface layer for fuel cell application
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Lam Hoang Hao, Le Quang Luan, Shin-ichi Sawada, Nguyen Quang Hung, Van-Phuc Dinh, N. V. Tiep, Tran Duy Tap, Tran Van Man, Yasunari Maekawa, Ekaterina A. Korneeva, Dinh Tran Trong Hieu, Kimio Yoshimura, Luu Anh Tuyen, and Shin Hasegawa
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chemistry.chemical_classification ,Materials science ,Polymers and Plastics ,General Chemistry ,Polymer ,Electrolyte ,Grafting ,Polyelectrolyte ,Surfaces, Coatings and Films ,Characterization (materials science) ,Membrane ,Chemical engineering ,chemistry ,Materials Chemistry ,Irradiation ,Surface layer - Published
- 2021
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28. Calculation of Binding Free Energy and Kinetic Rates with Flexible Protein Docking
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Tran, Phuoc Duy, Tran, Duy Phuoc, and Kitao, Akio
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Binding free energy ,Computational chemistry ,Chemistry ,Macromolecular docking ,Kinetic energy - Published
- 2021
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29. Highly efficient adsorbent based on novel cotton flower-like porous boron nitride for organic pollutant removal
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David Hui, Kamaldeep Sharma, Tran Duy Thanh, Kakali Maiti, Joong Hee Lee, and Nam Hoon Kim
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Materials science ,Mechanical Engineering ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Industrial and Manufacturing Engineering ,0104 chemical sciences ,Boric acid ,chemistry.chemical_compound ,Adsorption ,chemistry ,Chemical engineering ,Mechanics of Materials ,Boron nitride ,Specific surface area ,Ceramics and Composites ,Rhodamine B ,Water treatment ,Composite material ,0210 nano-technology ,Melamine ,Selectivity - Abstract
Development of highly efficient adsorbent materials for the wastewater treatment is an excellent, cheap, environmental friendly and sustainable approach. Herein, a novel cotton flower-like hierarchically porous boron nitride (BN) structure was successfully synthesized by pyrolizing a boric acid/melamine mixture at 1100 °C in a controlled flow rate ratio of N 2 /H 2 . The obtained porous BN material with a large specific surface area (SSA) of 1140 m 2 g −1 exhibited high selectivity, fast adsorption rate (∼96% for methylene blue (MB) after 20 min and ∼80% for rhodamine B (RhB) after 10 min) and high adsorption capacities (∼471.2 and 313.4 mg⋅g −1 for MB and RhB, respectively). The excellent selectivity of porous BN material towards dyes adsorption was confirmed from a mixed solution of dye and inorganic salts. In addition, porous BN material remain sustained without losing its adsorption activity even after 10 cycles and exhibited easy regeneration and good reusability which were achieved by a simple heating process. The obtained results indicated that the present porous BN material is a potential candidate for the removal of organic pollutants in water treatment applications.
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- 2017
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30. Surfactant-free synthesis of NiPd nanoalloy/graphene bifunctional nanocomposite for fuel cell
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Joong Hee Lee, Nam Hoon Kim, David Hui, Karthikeyan Gopalsamy, Tran Duy Thanh, and Jayaraman Balamurugan
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Materials science ,Nanoparticle ,Nanotechnology ,02 engineering and technology ,010402 general chemistry ,Electrocatalyst ,01 natural sciences ,Industrial and Manufacturing Engineering ,law.invention ,chemistry.chemical_compound ,law ,Composite material ,Bifunctional ,Bimetallic strip ,Nanocomposite ,Graphene ,Mechanical Engineering ,Chronoamperometry ,021001 nanoscience & nanotechnology ,0104 chemical sciences ,Chemical engineering ,chemistry ,Mechanics of Materials ,Ceramics and Composites ,Cyclic voltammetry ,0210 nano-technology - Abstract
Nickel-palladium alloy nanoparticles over graphene nanosheets (NiPd alloy NPs/GNS) are synthesized using ammonia-hydrazine method via a surfactant-free hydrothermal process. NiPd alloy NPs/GNS represent a new class of electrocatalyst with enhanced activity and stability for formic acid and ethanol oxidation reactions. The as-prepared catalysts are characterized using scanning electron microscopy (SEM), transmission electron microscopy (TEM), STEM-elemental mapping, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy. Cyclic voltammetry (CV) and chronoamperometry (CA) studies reveal that bimetallic alloy nanoparticles exhibit higher catalytic activity than monometallic catalysts toward electro-oxidation reactions. The higher activity is mainly attributed to the strong assembly of bimetallic NiPd alloy NPs over graphene sheets. The novel NiPd alloy NPs/GNS catalysts provide a new strategy for superior electro-catalytic performance in next-generation fuel cells.
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- 2017
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31. A novel hierarchical 3D N-Co-CNT@NG nanocomposite electrode for non-enzymatic glucose and hydrogen peroxide sensing applications
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Jayaraman Balamurugan, Gopalsamy Karthikeyan, Nam Hoon Kim, Joong Hee Lee, and Tran Duy Thanh
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Male ,Chemical substance ,Nanostructure ,Nitrogen ,Biomedical Engineering ,Biophysics ,Metal Nanoparticles ,Nanotechnology ,Biosensing Techniques ,02 engineering and technology ,010402 general chemistry ,Electrochemistry ,01 natural sciences ,law.invention ,Limit of Detection ,law ,Humans ,Detection limit ,Nanocomposite ,Nanotubes, Carbon ,Chemistry ,Graphene ,Electrochemical Techniques ,Hydrogen Peroxide ,General Medicine ,021001 nanoscience & nanotechnology ,0104 chemical sciences ,Glucose ,Linear range ,Electrode ,Graphite ,0210 nano-technology ,Biotechnology - Abstract
A novel 3D nanocomposite of nitrogen doped Co-CNTs over graphene sheets (3D N-Co-CNT@NG) have been successfully fabricated via a simple, scalable and one-step thermal decomposition method. This 3D hierarchical nanostructure provides an admirable conductive network for effective charge transfer and avoids the agglomeration of NG matrices, which examine direct as well as non-enzymatic responses to glucose oxidation and H2O2 reduction at a low potential. The novel electrode showed excellent electrochemical performance towards glucose oxidation, with high sensitivity of 9.05μAcm-2mM-1, a wide linear range from 0.025 to 10.83mM, and a detection limit of 100nM with a fast response time of less than 3s. Furthermore, non-enzymatic H2O2 sensors based on the 3D N-Co-CNT@NG electrode exhibited high sensitivity (28.66μAmM-1cm-2), wide linear range (2.0-7449μM), low detection limit of 2.0μM (S/N=3), excellent selectivity, decent reproducibility and long term stability. Such outstanding electrochemical performance can be endorsed to the large electroactive surface area, unique porous architecture, highly conductive networks, and synergistic interaction between N-Co-CNTs and nitrogen doped graphene (NG) in the novel 3D nanocomposite. This facile, cost-effective, sensitive, and selective glucose as well as H2O2 sensors are also proven to be appropriate for the detection of glucose as well as H2O2 in human serum.
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- 2017
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32. Hierarchical design of Cu1−xNixS nanosheets for high-performance asymmetric solid-state supercapacitors
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Jayaraman Balamurugan, Ok-Kyung Park, Tran Duy Thanh, Joong Hee Lee, Nam Hoon Kim, and Chao Li
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Supercapacitor ,Nickel sulfide ,Materials science ,Renewable Energy, Sustainability and the Environment ,Graphene ,Nanotechnology ,02 engineering and technology ,General Chemistry ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Capacitance ,Energy storage ,0104 chemical sciences ,law.invention ,chemistry.chemical_compound ,chemistry ,Chemical engineering ,law ,Electrode ,General Materials Science ,0210 nano-technology ,Current density ,Nanosheet - Abstract
Novel supercapacitor electrodes comprising hierarchical architectures with high specific surface areas, unique porosities, excellent conductivities, and admirable mechanical stabilities are necessary for developing high-performance solid-state supercapacitors. Herein, a novel ultra-thin copper nickel sulfide (Cu1−xNixS) nanosheet array supercapacitor electrode was constructed on a 3D Ni backbone through a powerful anion exchange technique and it demonstrated a unique architecture with a substantial degree of porosity. Accordingly, Cu1−xNixS plays an imperative role in the electrochemical energy storage characteristics of the electrode by accomplishing an ultra-high areal capacitance of 5.88 F cm−2 and a specific capacitance of 2672 F g−1 at a current density of 2 mA cm−2 with an excellent rate capability (71.26% capacitance retention at 20 mA cm−2) and a superior cycling performance (97.33% capacitance retention after 10 000 cycles). To design asymmetric supercapacitors (ASCs), Cu1−xNixS and N, S co-doped graphene nanosheets (NSGNSs) are employed as positive and negative electrodes, respectively. Remarkably, the fabricated ASC exhibits a potential window of ∼1.8 V, which demonstrates an ultra-high energy density of ∼94.05 W h kg−1 at 1.09 kW kg−1 as well as an excellent life cycle (95.86% capacitance retention after 10 000 cycles). Owing to this fact, this investigation offers a simple, scalable, and cost-effective approach for the fabrication of other ternary transition metal sulfides (TMSs), emphasizing great prospects in next-generation energy storage applications.
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- 2017
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33. Construct Validity of Radiographs of the Feet to Assess Joint Damage in Patients with Gout
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Annelies Boonen, Thea Schoonbrood, Casper Webers, Bart Spaetgens, Caroline van Durme, An Tran-Duy, Interne Geneeskunde, MUMC+: MA Alg Interne Geneeskunde (9), MUMC+: MA Med Staf Artsass Interne Geneeskunde (9), RS: CAPHRI - R3 - Functioning, Participating and Rehabilitation, MUMC+: MA Reumatologie (9), and Promovendi PHPC
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Male ,medicine.medical_specialty ,Radiography ,Immunology ,Dentistry ,PATIENT-REPORTED OUTCOME ,Severity of Illness Index ,03 medical and health sciences ,chemistry.chemical_compound ,0302 clinical medicine ,Rheumatology ,Quality of life ,QUALITY OF LIFE ,Internal medicine ,Foot Joints ,Severity of illness ,Immunology and Allergy ,Medicine ,Humans ,030212 general & internal medicine ,IMAGING ,Aged ,030203 arthritis & rheumatology ,RADIOGRAPHIC DAMAGE ,GOUT ,business.industry ,Foot ,Age Factors ,Construct validity ,Middle Aged ,medicine.disease ,Gout ,Uric Acid ,chemistry ,Physical therapy ,Disease Progression ,Uric acid ,Patient-reported outcome ,Female ,business - Abstract
Objective.To investigate construct validity of radiographic damage of the feet in gout.Methods.Radiographs of the feet were scored using the Sharp/van der Heijde method. Factors associated with damage were investigated by a negative binomial model, and contribution of damage to health by linear regressions.Results.Age, disease duration, serum uric acid, and tophi were associated with being erosive and erosion score. Tophi were associated with joint space narrowing. Erosions were associated (β 0.47, 95% CI 0.09–0.84) with physical function, but damage was not associated with overall physical health.Conclusion.Our results support construct validity for radiographs of the feet when assessing joint damage in gout.
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- 2017
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34. Incidence of Blossom-end Rot in Relation to Ca Concentration in Medium-sized Fruit Tomato Cultivar ‘Cindy Sweet’ as Affected by Elongated Light Period with Supplemental Lighting
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Tran Duy Vinh
- Subjects
0106 biological sciences ,Chemistry ,General Engineering ,General Earth and Planetary Sciences ,04 agricultural and veterinary sciences ,0405 other agricultural sciences ,01 natural sciences ,040501 horticulture ,010606 plant biology & botany ,General Environmental Science - Published
- 2017
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35. Abnormal volatile and normal stable bipolar resistive switching characteristics of hybrid nanocomposites: Morphology–defects–property ‘Relationship
- Author
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Quang Hung Nguyen, Anh Tuan Thanh Pham, Uyen Tu Thi Doan, Thang Bach Phan, Tran Duy Tap, Sungkyun Park, Thai Son Lo, Masataka Ohtani, Ngoc Kim Pham, and Anh Tuyen Luu
- Subjects
chemistry.chemical_classification ,Materials science ,Nanocomposite ,Morphology (linguistics) ,Mechanical Engineering ,Metals and Alloys ,02 engineering and technology ,Polymer ,Conductivity ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,Insulation layer ,Chemical engineering ,chemistry ,Zno nanoparticles ,Mechanics of Materials ,Resistive switching ,Materials Chemistry ,0210 nano-technology ,Layer (electronics) - Abstract
The characteristics of nano-fillers in a polymer matrix have a significant influence on the microstructural, thermo-mechanical, optical, and conductivity properties of organic-inorganic nanocomposites. In this study, we investigated the influence of inorganic component – ZnO nanoparticles (NPs) on the characteristics and properties of PVA-ZnO nanocomposites which have been applied as an insulation layer in a resistive switching (RS) device. Three nanocomposites originating from three different types of ZnO NPs exhibit different RS characteristics: Abnormal volatile RS is observed with the ∼20-nm-sized spherical-like NPs (Z1) and 15–20-nm-sized mixed shaped NPs (Z2), whereas normal nonvolatile bipolar RS is observed with the 50–150-nm-sized hexagonal rod-like NPs (Z3). The concentration and size of the intrinsic defects of the ZnO NPs as well as the thickness of the PVA-ZnO interface are responsible for the different charge transport paths, operating voltage ranges, and ON/OFF switching ratios of the memory devices. Simultaneously, the distinct sizes and morphologies of the ZnO NPs can affect the nanoholes among the PVA chains and induce various fractional free volumes in the nanocomposites. It may modify the conductivity of the nanocomposite layer or the resistance ratio of the memory devices. Understanding the influence of ZnO NPs size, morphology, and defects on the characteristics of RS of PVA-ZnO nanocomposites can help in the selection and management of functional applications, especially in the data storage field.
- Published
- 2021
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36. Optimization of Microwave-Assisted Extraction of Phlorotannin From Sargassum swartzii (Turn.) C. Ag. With Ethanol/Water
- Author
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Nguyen Mai Anh, Tran Duy Phong, Tran Quoc Toan, Ho Sy Tung, Nguyen Quang Tung, Pham Tri Nhut, Le Xuan Duy, Pham Thi Hong Minh, Do Huu Nghi, Dam Duc Tien, Hai Ha Pham Thi, and Nguyen Manh Linh
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Pharmacology ,chemistry.chemical_classification ,0303 health sciences ,biology ,Sargassum swartzii ,Chemistry ,010401 analytical chemistry ,Extraction (chemistry) ,Plant Science ,General Medicine ,biology.organism_classification ,01 natural sciences ,Phlorotannin ,Microwave assisted ,0104 chemical sciences ,03 medical and health sciences ,Complementary and alternative medicine ,Genus ,Sargassum ,Drug Discovery ,Botany ,030304 developmental biology - Abstract
Sargassum is a genus of brown macroalgae in the class Phaeophyta, distributed widely in all oceans, including those of Vietnam. Species of this genus have been proven to possess diverse biological activities, such as antioxidant, anti-fungal, and anti-inflammatory, along with many benefits and applications for human health, including anti-diabetic, obesity, and thrombosis. These benefits arise from a diverse chemical composition, with compounds such as fucoidan, mannitol, and especially phlorotannin—a group of phenolic derivatives found predominantly in brown algae. In this study, we evaluated and optimized the factors that affected the extraction process of phlorotannins from Sargassum swartzii (Turn.) C. Ag., a common species of brown macroalgae in Vietnam. The process utilized ethanol and water as the solvent system, and the extraction process was assisted with the use of microwaves. To carry out optimization studies, Response Surface Methodology (RSM) was adopted according to a Central Composite Desisgn (CCD), taking four processing factors into consideration, ethanol concentration (%, v/v), extraction time (minutes), solvent/material ratio (v/w), and microwave output power (W) as independent variables. Phlorotannin concentration (mgPhE/g) and extract mass (mg) were regarded as optimization outcomes. Experimental conditions that produced the highest phlorotannin yield from 10 g of S. swartzii are as follows: Extraction time of 65 minutes, ethanol concentration of 52%, microwave output power of 613 W, and solvent/material ratio of 33/1 (v/w). These conditions corresponded to a phlorotannin concentration of 5.59 ± 0.11 mg PhE/g, and a total extract content of 27.88 ± 0.13 mg/g.
- Published
- 2021
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37. Peanut skin extract mediated synthesis of gold nanoparticles, silver nanoparticles and gold–silver bionanocomposites for electrochemical Sudan IV sensing
- Author
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Joong Hee Lee, Soon-Il Yun, Alok Pani, Nam Hoon Kim, and Tran Duy Thanh
- Subjects
Silver ,Materials science ,Arachis ,Sudan IV ,Scanning electron microscope ,Analytical chemistry ,Metal Nanoparticles ,Nanoparticle ,02 engineering and technology ,01 natural sciences ,Silver nanoparticle ,Nanocomposites ,chemistry.chemical_compound ,Spectrophotometry ,medicine ,Electrical and Electronic Engineering ,Fourier transform infrared spectroscopy ,Electrodes ,Research Articles ,Detection limit ,medicine.diagnostic_test ,010401 analytical chemistry ,021001 nanoscience & nanotechnology ,0104 chemical sciences ,Electronic, Optical and Magnetic Materials ,chemistry ,Colloidal gold ,Gold ,0210 nano-technology ,Azo Compounds ,Biotechnology ,Nuclear chemistry - Abstract
Sustainable methods are needed for rapid and efficient detection of environmental and food pollutants. The Sudan group of dyes has been used extensively as adulterants in food and also are found to be polluting the soil and water bodies. There have been several methods for detection of Sudan dyes, but most of them are not practical enough for common use. In this study, the electrochemical detection efficiency and stability of gold nanoparticle (AuNPs), silver NPs and Au–Ag bionanocomposites, synthesised by peanut skin extract, modified glassy carbon electrode has been investigated. The synthesised nanomaterial samples were characterised, for their quality and quantity, using ultra–visible spectroscopy, inductive coupled plasma mass spectrophotometer, Fourier transform infrared spectroscopy, energy‐dispersive X‐ray spectroscopy, high‐resolution transmission electron microscope and field emission scanning electron microscope. The nanomaterial hybrid electrodes showed great efficiency and stability in the detection of Sudan IV compared with the other previous electrodes. The peak current of the Sudan IV oxidation and reduction was found to be proportional to its concentration, in the range of 10–80 µM, with a detection limit of 4 µM. The hybrid electrodes showed 90% stability in detection for 20 cycles.
- Published
- 2016
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38. Facile fabrication of FeN nanoparticles/nitrogen-doped graphene core-shell hybrid and its use as a platform for NADH detection in human blood serum
- Author
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Nam Hoon Kim, Tran Duy Thanh, Joong Hee Lee, and Jayaraman Balamurugan
- Subjects
Nanostructure ,Materials science ,Nitrogen ,Iron ,Biomedical Engineering ,Biophysics ,Nanoparticle ,Nanotechnology ,Biosensing Techniques ,02 engineering and technology ,Nicotinamide adenine dinucleotide ,010402 general chemistry ,Electrocatalyst ,01 natural sciences ,law.invention ,chemistry.chemical_compound ,Limit of Detection ,law ,Electrochemistry ,Humans ,Detection limit ,Graphene ,Reproducibility of Results ,Electrochemical Techniques ,General Medicine ,NAD ,021001 nanoscience & nanotechnology ,Ascorbic acid ,0104 chemical sciences ,chemistry ,Chemical engineering ,Nanoparticles ,Graphite ,0210 nano-technology ,Oxidation-Reduction ,Biosensor ,Biotechnology - Abstract
Herein, we present a novel strategy for the synthesis of an iron nitride nanoparticles-encapsulated nitrogen-doped graphene (FeN NPs/NG) core-shell hierarchical nanostructure to boost the electrochemical performance in a highly sensitive, selective, reproducible, and stable sensing platform for nicotinamide adenine dinucleotide (NADH). This core-shell hierarchical nanostructure provides an excellent conductive network for effective charge transfer and avoids the agglomeration and restacking of NG sheets, which provides better access to the electrode material for NADH oxidation. The FeN NPs/NG core-shell hierarchical nanostructure demonstrates direct and mediatorless responses to NADH oxidation at a low potential. This material displays a high sensitivity of 0.028μA/μMcm(2), a wide linear range from 0.4 to 718μM, and a detection limit of 25nM with a fast response time of less than 3s. The interferences from common interferents, such as glucose, uric acid, dopamine, and ascorbic acid, are negligible. The fabricated sensor was further tested for the determination of NADH in human blood serum. The resulting high sensitivity, excellent selectivity, outstanding stability, and good reproducibility make the proposed FeN NPs/NG core-shell hierarchical nanostructure as a promising candidate for biomedical applications.
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- 2016
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39. Effective seed-assisted synthesis of gold nanoparticles anchored nitrogen-doped graphene for electrochemical detection of glucose and dopamine
- Author
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Jayaraman Balamurugan, Seung Hee Lee, Joong Hee Lee, Nam Hoon Kim, and Tran Duy Thanh
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Blood Glucose ,Chemical substance ,Nitrogen ,Dopamine ,Dopamine Agents ,Biomedical Engineering ,Biophysics ,Metal Nanoparticles ,Nanotechnology ,02 engineering and technology ,010402 general chemistry ,Electrocatalyst ,01 natural sciences ,Catalysis ,law.invention ,Magazine ,Limit of Detection ,law ,Electrochemistry ,Humans ,Detection limit ,Graphene ,Chemistry ,Electrochemical Techniques ,General Medicine ,021001 nanoscience & nanotechnology ,0104 chemical sciences ,Colloidal gold ,Graphite ,Gold ,0210 nano-technology ,Selectivity ,Biotechnology ,Nuclear chemistry - Abstract
A novel gold nanoparticle-anchored nitrogen-doped graphene (AuNP/NG) nanohybrid was synthesized through a seed-assisted growth method, as an effective electrocatalyst for glucose and dopamine detection. The AuNP/NG nanohybrids exhibited high sensitivity and selectivity toward glucose and dopamine sensing applications. The as-synthesized nanohybrids exhibited excellent catalytic activity toward glucose, with a linear response throughout the concentration range from 40μM to 16.1mM, a detection limit of 12μM, and a short response time (∼ 10s). It also exhibited an excellent response toward DA, with a wide detection range from 30nM to 48μM, a low detection limit of 10nM, and a short response time (∼ 8s). Furthermore, it also showed long-term stability and high selectivity for the target analytes. These results imply that such nanohybrids show a great potential for electrochemical biosensing application.
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- 2016
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40. Enhanced mechanical and thermal properties of recycled ABS/nitrile rubber/nanofil N15 nanocomposites
- Author
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Joong Hee Lee, Anne-Cécile Grillet, Nguyen Thi Thuong, Nam Hoon Kim, Nguyen Dang Mao, and Tran Duy Thanh
- Subjects
Materials science ,Nanocomposite ,Morphology (linguistics) ,Scanning electron microscope ,Acrylonitrile butadiene styrene ,Mechanical Engineering ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Industrial and Manufacturing Engineering ,0104 chemical sciences ,chemistry.chemical_compound ,chemistry ,Mechanics of Materials ,Transmission electron microscopy ,Ceramics and Composites ,Thermal stability ,Composite material ,0210 nano-technology ,Hybrid material ,Nitrile rubber - Abstract
Hybrid materials based on recycled acrylonitrile butadiene styrene (re-ABS) and nitrile rubber (NBR) upgraded by montmorrilonite nanofil 15 (N15) were prepared by melt processing. The morphology and structure of the nanocomposites were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), and transmission electron microscopy (TEM) analyses. As revealed by SEM, NBR and N15 were homogeneously dispersed in the re-ABS matrix. The XRD and TEM studies demonstrated that N15 was mainly located in the re-ABS matrix in the form of an intercalated-exfoliated mixed structure that led to an increase of the melting viscosity of the materials. The mechanical properties of the nanocomposites showed a good balance when adding 1 phr (parts per hundred parts of resin) of N15 into the re-ABS/NBR (90/10) blend. Furthermore, the thermal stability of the nanocomposites was also improved in the presence of NBR and N15.
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- 2016
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41. Facile synthesis of vanadium nitride/nitrogen-doped graphene composite as stable high performance anode materials for supercapacitors
- Author
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Nam Hoon Kim, Jayaraman Balamurugan, Gopalsamy Karthikeyan, Tran Duy Thanh, and Joong Hee Lee
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Supercapacitor ,Materials science ,Nanostructure ,Renewable Energy, Sustainability and the Environment ,Graphene ,Vanadium nitride ,Composite number ,Energy Engineering and Power Technology ,Nanotechnology ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Capacitance ,0104 chemical sciences ,law.invention ,Anode ,chemistry.chemical_compound ,Chemical engineering ,chemistry ,law ,Electrode ,Electrical and Electronic Engineering ,Physical and Theoretical Chemistry ,0210 nano-technology - Abstract
Novel vanadium nitride/nitrogen-doped graphene (VN/NG) composite was fabricated and used as stable high performance anode materials for supercapacitors. The VN/NG composite anode material exhibited excellent rate capability, outstanding cycling stability, and superior performance. FE-SEM and TEM studies of VN/NG composite revealed that ultra-thin VN nanostructures were homogeneously distributed on flexible NG nanosheets. The NG provided a highly conductive network to boost the charge transport involved during the capacitance generation and also aided the dispersion of nanostructured VN within the NG network. The synergetic VN/NG composite exhibited an ultra-high specific capacitance of 445 F g −1 at 1 Ag −1 with a wide operation window (−1.2 to 0 V) and showed outstanding rate capability (98.66% capacity retention after 10,000 cycles at 10 Ag −1 ). The VN/NG electrode offered a maximum energy density (∼81.73 Wh kg −1 ) and an ultra-high power density (∼28.82 kW kg −1 at 51.24 Wh kg −1 ). The cycling performance of the VN/NG composite was superior to that of pure VN nanostructure. These finding open a new path way to the designated fabrication of VN/NG composite as anode materials in the development of high performance energy storage devices.
- Published
- 2016
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42. Facile fabrication of Co2CuS4 nanoparticle anchored N-doped graphene for high-performance asymmetric supercapacitors
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Nam Hoon Kim, Jayaraman Balamurugan, Meng Guo, Joong Hee Lee, and Tran Duy Thanh
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Supercapacitor ,Materials science ,Renewable Energy, Sustainability and the Environment ,Composite number ,Nanoparticle ,chemistry.chemical_element ,Nanotechnology ,02 engineering and technology ,General Chemistry ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Electrochemistry ,01 natural sciences ,Capacitance ,0104 chemical sciences ,Copper sulfide ,chemistry.chemical_compound ,chemistry ,Chemical engineering ,General Materials Science ,0210 nano-technology ,Ternary operation ,Cobalt - Abstract
A novel strategy for the synthesis of high-quality ternary cobalt copper sulfide nanoparticles (NPs) anchored on nitrogen doped graphene nanosheets (Co2CuS4/NG) was developed via a one-pot solvothermal method. FE-SEM and TEM images showed that the Co2CuS4 NPs with an average size of ∼21 nm were anchored to NG nanosheets. The NG nanosheets provide a large surface area to reduce self-aggregation and confine the shape of the Co2CuS4 NPs for a highly conductive network to boost the charge transport properties of energy storage devices. Impressively, the synergetic Co2CuS4/NG composite showed a high specific capacitance of ∼1005 F g−1 at 1 A g−1, excellent rate capability (770 F g−1 at 50 A g−1), and outstanding stability (96.3% capacitance retention after 5000 cycles). The electrochemical performance of the Co2CuS4/NG composite was superior to that of monometallic CoS/NG, Cu2S/NG composite, pure Co2CuS4, and NG. An asymmetric supercapacitor device fabricated using the Co2CuS4/NG composite as the positive electrode material and NG as the negative electrode material illustrates the outstanding performance for practical energy storage devices. The asymmetric supercapacitor device delivers superb energy density (53.3 W h kg−1), high power density (∼10 936 W kg−1 at 38.4 W h kg−1), and a long-cycle life (∼4000 times).
- Published
- 2016
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43. Chitosan-MnO2 nanocomposite for effective removal of Cr (VI) from aqueous solution
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Thi-Thuy Luu, Anh Tuyen Luu, Minh-Doan Nguyen, Le Van Tan, Trong Phuc Phan, Thi-Thanh-Thao Do, Van-Phuc Dinh, Thien-Hoang Ho, Trinh Duy Nguyen, Tran Duy Tap, and Quang Hung Nguyen
- Subjects
Langmuir ,Environmental Engineering ,Aqueous solution ,Materials science ,Nanocomposite ,Health, Toxicology and Mutagenesis ,0208 environmental biotechnology ,Inorganic chemistry ,Public Health, Environmental and Occupational Health ,02 engineering and technology ,General Medicine ,General Chemistry ,010501 environmental sciences ,01 natural sciences ,Pollution ,020801 environmental engineering ,Chitosan ,chemistry.chemical_compound ,Adsorption ,chemistry ,Wastewater ,Monolayer ,Environmental Chemistry ,Freundlich equation ,0105 earth and related environmental sciences - Abstract
In this report, the adsorption of Cr(VI) onto MnO2/CS nanocomposite material from aqueous solution is investigated. All the factors, which affect the adsorption, such as pH, adsorption time, Cr(VI) initial concentration and adsorbent dosage, are also examined. The results obtained show that the Cr(VI) uptake is strongly affected by pH and ion strength. Analysis within the nonlinear isotherm models indicates that the Sips isotherm combining with the Langmuir and Freundlich models offer the best fit to the experimental data due to the obtained highest R2 and smallest RMSE and χ2 values. The calculated Langmuir monolayer adsorption capacity is 61.56 mg g−1 at pH of 2.0 and adsorption time of 120 min. Moreover, the mechanism studies by combining theoretical models with analytical spectroscopies reveal that the electrostatic attraction plays the important role to the uptake of Cr(VI) onto MnO2/CS nanocomposite. Therefore, the present nanocomposite material can be applied to remove total Cr from wastewater produced by the galvanized manufacturing factory with a relatively high efficiency.
- Published
- 2020
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44. Effects of Y3+on the enhancement NIR emission of Bi+-Er3+ co-doped in transparent silicate glass-ceramics for Erbium-doped fiber amplifier (EDFA)
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Ho Kim Dan, Dacheng Zhou, Dai-Nam Le, Jianbei Qiu, Rongfei Wang, Hieu T. Nguyen-Truong, Ha Xuan Vinh, Tran Duy Tap, and Nguyen Minh Ty
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Materials science ,Biophysics ,Analytical chemistry ,02 engineering and technology ,010402 general chemistry ,01 natural sciences ,Biochemistry ,law.invention ,chemistry.chemical_compound ,law ,Differential thermal analysis ,Ceramic ,Crystallization ,Optical amplifier ,General Chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,Atomic and Molecular Physics, and Optics ,Silicate ,0104 chemical sciences ,Full width at half maximum ,chemistry ,Transmission electron microscopy ,visual_art ,visual_art.visual_art_medium ,0210 nano-technology ,Glass transition - Abstract
We study effects of Y3+ on the enhancement near-infrared emission of Bi+-Er3+ co-doped in transparent silicate glass-ceramics for optical amplifiers. The differential thermal analysis, X-ray diffraction, transmission electron microscopy to determine the effects of Y3+ on the structure of BaF2 nanocrystals in glass-ceramics. With increasing the concentration of Y3+ from 0 up to 10 mol. %, the near-infrared emission intensities of Bi+-doped, Er3+-doped and Bi+-Er3+ co-doped bands centered at 1276 and 1546 nm also increase, and the full width at half maximum is about 460 nm. At the same time, when the concentration of YF3 increases from 4 up to 10 mol. %: all the glass transition temperature, the crystallization onset temperature, and the crystallization peaks temperature increase, resulting in a shift of the 2θ with a difference Δθ = 0.3°. In addition, we study the thermal properties through differential thermal analysis curves.
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- 2020
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45. Multiwall carbon nanotube modified by antimony oxide (Sb2O3/MWCNTs) paste electrode for the simultaneous electrochemical detection of cadmium and lead ions
- Author
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Ba Son Nguyen, Tran Thi Bich Phuong, Tran Le Hai, Ly Cam Hung, Van-Huy Nguyen, Tran Duy Hai, and Bui Thi Thu Ha
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Cadmium ,Materials science ,010401 analytical chemistry ,Composite number ,Inorganic chemistry ,chemistry.chemical_element ,02 engineering and technology ,Electrochemical detection ,Carbon nanotube ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,Analytical Chemistry ,law.invention ,Ion ,Anodic stripping voltammetry ,chemistry ,law ,Electrode ,Antimony oxide ,0210 nano-technology ,Spectroscopy - Abstract
In this study, a sensitive and reliable anodic stripping voltammetry (ASV) using a series of multiwall carbon nanotube modified by antimony oxide (Sb2O3/MWCNTs) paste electrodes was successfully introduced for the simultaneous electrochemical detection of Cd2+ and Pb2+ ions. Firstly, a composite of multiwall carbon nanotubes (MWCNTs) was successfully used to preparing a paste electrode. Then, the MWCNTs bulk electrode was further modified with various concentrations of Sb2O3 (1, 3, and 4 wt.%, respectively) for improving the cadmium ions (Cd2+) and lead ions (Pb2+) detection ability. Among the Sb2O3/MWCNTs electrodes, the modified electrode by 3 wt.% Sb2O3 exhibits remarkable analytical detection for Cd2+ and Pb2+ by linear sweep anodic stripping voltammetry (LSASV) technique. The proper linear curves of current response versus the concentration of Cd2+ (80–150 ppb) and Pb2+ (5–35 ppb) could be observed. Interestingly, the analytical sensitivity of the mixture Cd2+ and Pb2+ were 1.932 and 2.694 μA⋅L⋅μg–1, respectively, which were higher than 1.5 and 1.3 folds of the individual ions. It expects that the Sb2O3/MWCNTs paste electrode could provide a significant improvement to the electrode for the simultaneous electrochemical detection of Cd2+ and Pb2+ ions.
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- 2020
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46. Synthesis and anti-proliferative activity of novel azazerumbone conjugates with chalcones
- Author
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Pham Minh Quan, Luu Van Chinh, Vuong Van Truong, Nguyen Thi Nga, Sang-Hun Jung, Truong Ngoc Hung, and Tran Duy Nam
- Subjects
Chalcone ,Lactams ,Stereochemistry ,Clinical Biochemistry ,Pharmaceutical Science ,Antineoplastic Agents ,Stereoisomerism ,Biochemistry ,Structure-Activity Relationship ,chemistry.chemical_compound ,Chalcones ,Cell Line, Tumor ,Amide ,Drug Discovery ,Humans ,Structure–activity relationship ,Ellipticines ,Molecular Biology ,Organic Chemistry ,Azazerumbone ,chemistry ,Cell culture ,Molecular Medicine ,Drug Screening Assays, Antitumor ,Sesquiterpenes ,Linker ,Conjugate - Abstract
The conjugation of azazerumbone ((3E,7E,11E)-5,5,8,12-tetramethylazacyclododeca-3,7,11-trien-2-one (7)) and 2,4-dihydroxychalcones was carried out for the preparation of novel target compounds 9a-g with 1-ethylene-4-methylene-1,2,3-triazole linker and 10a-f with propylene linker between amide nitrogen of azazerumbone and 4-hydroxy group of chalcone. The anti-proliferative activity of these compounds against the LU-1, Hep-G2, MCF-7 and SW480 human cancer cell lines were significantly improved compared to those of azazerumbone or zerumbone. The anti-proliferative activities of (3E,7E,11E)-1-((1-(2-(3-hydroxy-4-((E)-3-(3-methoxyphenyl)acryloyl)phenoxy)ethyl)-1H-1,2,3-triazol-4-yl)methyl)-5,5,8,12-tetramethyl azacyclododeca-3,7,11-trien-2-one (9b) and (3E,7E,11E)-1-(3-(4-((E)-3-(3,4,5-trimethoxyphenyl)acryloyl)phenoxy)propyl)-5,5,8,12-tetramethylazacyclododeca-3,7,11-trien-2-one (10d) are nearly comparable to those of ellipticine.
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- 2015
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47. Novel route to synthesis of N-doped graphene/Cu–Ni oxide composite for high electrochemical performance
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Seok-Bong Heo, Nam Hoon Kim, Tran Duy Thanh, Joong Hee Lee, and Jayaraman Balamurugan
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Supercapacitor ,Materials science ,Graphene ,Composite number ,Oxide ,Nanoparticle ,Nanotechnology ,General Chemistry ,Electrochemistry ,Capacitance ,law.invention ,chemistry.chemical_compound ,Chemical engineering ,chemistry ,law ,General Materials Science ,Current density - Abstract
A facile and cost-effective one-pot solvothermal method has been successfully developed to synthesize an N-doped graphene (NG) and copper–nickel oxide (CuNiO) composite. The novel NG/CuNiO composite is proposed to be used as an electrode material for supercapacitors and non-enzymatic glucose sensors. Transmission electron microscopy images indicate the formation of CuNiO nanoparticles with an average diameter of approximately 5.6 nm, with good dispersion on the NG sheets. The composite exhibited an excellent specific capacity of ≈892 F g−1 (current density of 1 A g−1) and high long-cycle stability with a 98.5% retention in specific capacitance after 5000 cycles at a current density of 5 A g−1. This superior electrochemical performance is attributed to high charge mobility, the flexibility of the N-doped graphene structure, and the synergetic effect between CuNiO nanoparticles and NG sheets. Further, the proposed sensor exhibited rapid response (
- Published
- 2015
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48. Hierarchical Structure–Property Relationships in Graft-Type Fluorinated Polymer Electrolyte Membranes Using Small- and Ultrasmall-Angle X-ray Scattering Analysis
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Masato Ohnuma, Yosuke Katsumura, Shin-ichi Sawada, Kimio Yoshimura, Shin Hasegawa, Yasunari Maekawa, Tran Duy Tap, and Yojiro Oba
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chemistry.chemical_classification ,Materials science ,Polymers and Plastics ,Organic Chemistry ,Polymer ,Electrolyte ,Conductivity ,Inorganic Chemistry ,chemistry.chemical_compound ,Crystallography ,Membrane ,ETFE ,chemistry ,Chemical engineering ,Phase (matter) ,Nafion ,Materials Chemistry ,Crystallite - Abstract
The hierarchical structures of graft-type poly(ethylene-co-tetrafluoroethylene) (ETFE)-based polymer electrolyte membranes (ETFE-PEMs) were investigated using small- and ultrasmall-angle X-ray scattering experiments. The ETFE-PEMs with ion exchange capacities (IECs) 2.7 mmol/g showed a new phase of crystallite network domains with a d-range of 225–256 nm, indicating a phase transition from oriented crystallite to crystallite network structures in the IEC range of 2.4–2.7 mmol/g. Noted that for the ETFE-PEMs with high IECs higher conductivity at 30% RH and compatible tensile strengths at 100% RH and 80 °C, compared with Nafion, originated from the well-interconnected ion channels around the crystallites and the remaining lamellar crystals and crystal...
- Published
- 2014
- Full Text
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49. Incidence of Blossom-end Rot in Relation to the Water-soluble Calcium Concentration in Tomato Fruits as Affected by Calcium Nutrition and Cropping Season
- Author
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Yoshiyuki Tanaka, Tran Duy Vinh, Nobuyuki Irie, Tanjuro Goto, Yuichi Yoshida, Mitsuo Ooyama, and Ken-ichiro Yasuba
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Water soluble ,Agronomy ,chemistry ,Incidence (epidemiology) ,Calcium concentration ,chemistry.chemical_element ,Biology ,Calcium ,Cropping - Published
- 2014
- Full Text
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50. Effect of graphite nanoplatelets on the structure and properties of PA6-elastomer nanocomposites
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Jiřina Hromádková, Ivan Kelnar, Ludmila Kaprálková, and Tran Duy Thanh
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chemistry.chemical_classification ,Materials science ,Nanocomposite ,Polymers and Plastics ,Graphene ,Organic Chemistry ,General Physics and Astronomy ,Polymer ,Epoxy ,Elastomer ,law.invention ,Polybutadiene ,chemistry ,law ,visual_art ,Polyamide ,Materials Chemistry ,visual_art.visual_art_medium ,Graphite ,Composite material - Abstract
The combination of polymer blending and nanocomposite concepts represents a progressive approach to meet the increasingly high requirements of the properties of materials for different applications. This work addresses the reinforcement and structure-directing effects of graphite nanoplatelets (xGnPs) added into a Polyamide 6 (PA6)/elastomer system. Three different elastomers were used: an ethene-propene copolymer (EPR), an ethene-methacrylate copolymer (EMA), and an aminated polybutadiene (ATB). The addition of xGnP caused a reduction in the size of the EPR, EMA and ATB domains; the most significant size reduction was observed for EPR, which had the lowest compatibility with the polymer matrix. The xGnP was primarily located in the PA6 phase due to the presence of epoxy groups on the surface of the xGnP, which promoted the affinity to the PA6 matrix. At the same time, the content of the epoxy groups is low enough to achieve sufficient modification of xGnPs, e.g., with alkyl amines (∼6%), thus providing compatibility with nonpolar EPR. The evaluation of the mechanical parameters indicates that the combination of elastomers and xGnP leads to a polyamide material with enhanced strength, stiffness and toughness. Finally, it may be expected that the analogous graphene oxide, which has a higher potential for modification and finer platelets, will be a more effective nanofiller.
- Published
- 2014
- Full Text
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