38 results on '"Le HA"'
Search Results
2. Synthesis of material MOFs (Fe-BTC) by mechanic-chemical method and its application in the reactive dye degradation
- Author
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Giang Le Ha, Tai Bui Manh, Doanh Truog Cong, Tuan Vu Anh, Hoa Nguyen Thi Thanh, Trang Pham Thi Thu, Hoa Vu Thi, and Manh Nguyen Ba
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chemistry.chemical_compound ,Chemical engineering ,chemistry ,Degradation (geology) ,Reactive dye - Abstract
Nano Fe-BTC materials were successfully synthesized by mechanical chemical grinding method. Samples were characterized by X-ray difraction (XRD), Fourier-transform infrared spectroscopy (FTIR), N2 adsorption–desorption, Scanning electron microscopy (SEM), Energy-dispersive X-ray spectroscopy (EDS). SEM image of Fe-BTC-60 showed the particle size of 40–60 nm. Fe-BTC nanocomposites were tested for the photocatalytic degradation of reactive yellow 145 (RY-145) in aqueous solution. Fe-BTC composites exhibited high photocatalytic activity. Thus, at pH of 3 and high initial concentration of 100 mg RY-145/L, removal efficiency reached the value of 97.45% after 90 min of reaction.
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- 2021
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3. Application of bacteriophage cocktail to control multi-drug resistant Pseudomonas aeruginosa
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Diep The Tai, Nguyen Anh Quang, Nguyen Thi Ngoc Nhi, and Le Ha Duc Anh
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Bacteriophage ,biology ,Chemistry ,Pseudomonas aeruginosa ,medicine ,Multi drug resistant ,biology.organism_classification ,medicine.disease_cause ,Microbiology - Published
- 2021
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4. Angiotensin-converting enzyme inhibitory and antibacterial activities of low molecular weight peptides derived from spent brewer’s yeast
- Author
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Quan Le Ha, Dang Thi Thu, Cao Hai Yen, Pham Thi Hang Nga, and Pham Thi Thu Hien
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biology ,Biochemistry ,Chemistry ,biology.protein ,Angiotensin-converting enzyme ,Inhibitory postsynaptic potential ,Yeast - Abstract
According to the World Health Organization (WHO), hypertension is one of the most common chronic diseases. Cardiovascular disease causes 17.5 million deaths each year, in which hypertension is a direct cause to the death of up to 40%. This hypertension is caused by angiotensin-converting enzyme (ACE). ACE inhibitors consider as an effective therapy in hypertension treatment.Many ACE inhibitors are synthesized by chemical pathways to control high blood pressure, however, these drugs often cause side effects. Therefore, in the last two decades, many authors have been interested in studying and producing a variety of ACE inhibitory peptides, which are naturally derived (plants, animals, and microorganisms) that help reduces blood pressure and less cause side effects. On the other hand, biologically active peptides that are resistant to pathogenic bacteria are also of special interest. In this study, we refer to the limited hydrolysis of spent brewer's yeast by proteases to collect peptides with a molecular size of ≤ 10, 5 and 3 kDa. Peptide fraction with molecular size ≤ 10 kDa have ACE inhibitory activity. The results showed that smaller peptide fractions had higher ACE inhibitory activity. At concentration of 30 µg/mL, inhibitory activitiy of peptides with molecular sizes ≤ 10, 5, 3 kDa was 16.3, 27.7 and 32.7%, respectively, and the best IC50 was 48,85 µg/ml. The lowest peptide concentration for completely inhibition bacteria after 24 h of incubation was 30 mg/mL (V. cholerae), 35 mg/mL (E. coli) and 50 mg/mL (S. typhi).
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- 2020
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5. Preparation of hydrogel calcium-alginate microparticles via microfluidic device for Cu2+ treatment
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Hong Hoang Thu, Mai Mac Thi Thu, Vu Tran Khac, Trung Dang Cu, Dung Dang Trung, Duc Ta Hong, and Phuong Le Ha
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chemistry.chemical_compound ,Calcium alginate ,Chemical engineering ,Chemistry ,Microfluidics - Abstract
Alginate-based hydrogels are attracted much attention in biomedical and chemical field, and their size and shape are significant to their applications like drug delivery and cell encapsulation. Monodisperse sodium alginate microdroplets are produced using a flow-focusing microfluidic device (MFFD) by adjusting the flow rate on the continuous phase (soybean oil) and the dispersed phase (sodium alginate solution). The external gelation process of sodium alginate microdroplets occurs outside the chanel in a calcium chloride solution to form calcium alginate hydrogel particales. The shape, size and size distribution of these calcium alginate hydrogel particles depend strongly on the flow rate inside the MFFD. By optimizing the parameters, the hydrogel microparticles were obtained with diameters ranging from 70 µm to 100 µm with size distribution under 10%, depending on experimental conditions. The removal of Cu2+ ions by the absorption of hydrogel microparticles was also demonstrated.
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- 2020
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6. EFFECT OF RATIO OF BEES WAX AND CARNAUBA WAX IN MIXED WAX ON RESPIRATION RATE, WEIGHT LOSS, FRUIT DECAY AND CHEMICAL QUALITY OF VIETNAMESE PASSION FRUITS DURING LOW TEMPERATURE STORAGE
- Author
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Nguyen Sang and Le Ha Hai
- Subjects
Wax ,Applied Microbiology and Biotechnology ,chemistry.chemical_compound ,Horticulture ,chemistry ,Chemical quality ,Weight loss ,visual_art ,medicine ,visual_art.visual_art_medium ,Carnauba wax ,medicine.symptom ,Respiration rate ,Biotechnology - Published
- 2020
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7. Catalytic Conversion of Cellulose to 5-hydroxymethylfurfural (5-HMF) Over Nano SO42--ZrO2 /MCM-41 Catalysts
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Le Ha Giang, Pham Tung Son, Vu Anh Tuan, Nguyen Ba Manh, Vu Quang Loi, Le Thanh Son, and Pham Thi Thu Trang
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chemistry.chemical_compound ,chemistry ,Chemical engineering ,MCM-41 ,5-hydroxymethylfurfural ,Nano ,Cellulose ,Catalysis - Abstract
A zirconium catalyst system supported on MCM-41 (S-Z) with various weight components (4-20 wt.%) Was synthesized by the sol-gel method. Structure and Morphology Catalysts were characterized by X-RD, TEM, BET, FT-IR and TPD-NH3 methods. In this catalyst, ZrO2 is highly dispersed on the surface of MCM-41 capillaries. Catalytic activity and selectivity were evaluated by the effectiveness of mild hydrothermal decomposition of cellulose to 5-hydroxymethyl furfural (5-HMF). The results show that a catalyst with medium acidity exhibits a high selectivity of 5-HMF. Keywords: S-Zr/MCM-41 materials, sol-gel methods, cellulose, 5-HMF.
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- 2020
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8. USING γ RAY-INDUCED SILVER NANOPARTICLES ON CONTROL OF CLUBROOT DISEASE OF CHINESE CABBAGE CAUSED BY PLASMODIOPHORA BRASSICAE
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Le Thi Anh Tu and Pham Thi Le Ha
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Clubroot ,Horticulture ,Chemistry ,fungi ,medicine ,food and beverages ,Plasmodiophora brassicae ,medicine.disease ,Silver nanoparticle - Abstract
Plasmodiophora brassicae- the casual cause of clubroot disease of plants belonging to the family Brassicaceae. This soil-borne fungus infects plants through root hairs. Diseased roots become swollen and deformed. Thus, it’s difficult for plants to absorb water and nutrients. There are some methods used to control this disease including soil fumigation, soil pH control, fungicides, surfactants applications, calcium supplementation, but the results are still restricted. Plasmodiophora brassicae was isolated, identified and artificial inoculated on the Chinese cabbage. The rate of root hair infection and gall formation depended on the spore density and growth media. The increase of the pathogen density lead to the increase of disease symptoms. Silver nanoparticles (SNPs) are widely used as an agent for antifungal treatment. The antimicrobial activity of the nanoparticles varies on the size, shape, and the function of the surface area. The γ - irradiation method to synthesize SNPs is known as a method that can be controlled the out coming sizes, shapes and size distribution of particles. The average diameter of silver nanoparticles in this research was 9.5nm. In the liquid culture and soil, SNPs exhibited a controlling effect on P. brassicae. The fungicide activity depended on the SNP concentrations and the medium; no disease symptoms were found at the SNP concentrations of 1.06 ppm in the liquid culture, and 10 and 20 ppm in soil. Results of the study also showed that the biomass and height of infected plants were much lower than those of the healthy plants. Comparing to the plants that were grown in the sterilized soil, there was not significant difference between the biomass and the height of plants exposed to pathogen and treated with SNPs.
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- 2018
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9. Optimization for continuous overflow proteolytic hydrolysis of spent brewer’s yeast by using proteases
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Nguyen Thi Thanh Ngoc, Quan Le Ha, and Dinh Van Thuan
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Proteases ,Hydrolysis ,Biochemistry ,Chemistry ,Yeast - Abstract
A large amount of spent yeast as by-product is annually generated from brewing industry and it contains about 50-55% protein with good balance of amino acids. The hydrolysate produced from spent brewer’s yeast may be used in food application. The yield of proteolylic hydrolysis for spent brewer’s yeast and amino acid contents of hydrolysates depend on factors such as temperature, pH value, type of used enzyme and ratio enzyme/substrate, time. Besides, applied hydrolysing methods (batch-, or continuous method) has effected on degree of hydrolysis. With the purpose of how proteolytic hydrolysis having effects on the spent brewer’s yeast for food application in industrial scale, continuous overflow method was used in this study. Bitterness of hydrolysate and the yield of continuous overflow proteolytic hydrolysis process are the two interested factors for protein hydrolysis. In this report, it is dealt with determination for optimal conditions to obtain the highest yield of hydrolysis process and the lowest bitterness of hydrolysate. Response surface methodology (RSM) was used to determine optimal condition for continuous overflow proteolytic hydrolysis of spent brewer’s yeast. The optimal conditions for obtaining high degree of hydrolysis and low bitterness are determined as followings: ratio of enzyme mixture (alcalase 7.5 U/g and flavourzyme 10 U/g), pH at 7.5, hydrolysis temperature at 51oC and hydrolysis time of 9 hours. Under the optimal conditions, the yield of hydrolysis was 59.62% ± 0.027 and the bitterness equivalently with concentration of quinine was 7.86 ± 0.033 μmol /ml.
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- 2018
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10. Enhanced efficiency of silicon micro-pyramids/poly(3,4-ethylenedioxythiophene):polystyrene sulfonate/gold nanoparticles hybrid solar cells
- Author
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Bui Hung Thang, Naoki Fukata, Nguyen Van Hao, Nguyen Ngoc Anh, Le Ha Chi, Phan Ngoc Minh, Pham Van Trinh, Cao Tuan Anh, Ngo Thi Bac, and Nguyen Van Chuc
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Materials science ,Silicon ,Mechanical Engineering ,Energy conversion efficiency ,chemistry.chemical_element ,Hybrid solar cell ,Condensed Matter Physics ,law.invention ,Polystyrene sulfonate ,chemistry.chemical_compound ,chemistry ,Chemical engineering ,PEDOT:PSS ,Mechanics of Materials ,law ,Solar cell ,General Materials Science ,Surface plasmon resonance ,Poly(3,4-ethylenedioxythiophene) - Abstract
The hybrid solar cells have been receiving great attention as a promising candidate for the next generation of energy-harvesting devices. In this study, we present some results on the fabrication and characterization of n-type silicon micro-pyramid (SiMPs)/poly (3,4-ethylenedioxythiophene): poly (styrenesulfonate) (PEDOT:PSS) hybrid solar cells. SiMPs were prepared by a chemical etching method and their influence on the performance of the hybrid solar cells was investigated. The obtained results showed that the micro-pyramidal structures could provide an adequate generation of charge carriers by relatively low reflectance. The hybrid solar cell using SiMPs showed a power conversion efficiency (PCE) to be 5.24% which improves about 40% compared to that of the planar Si solar cell (3.68%). Besides, the effect of AuNP concentrations on the performance of the hybrid solar cell was also investigated. The maximum PCE was measured to be 7.55% with a device containing 0.5 wt% AuNP concentration, which is 44% higher compared to that of the solar cells without AuNPs. The enhancement is attributed to the increase in electrical conductivity and localized surface plasmon resonance of the PEDOT:PSS coating layer due to the addition of the AuNPs.
- Published
- 2022
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11. The The research to improve the mechanical properties and the water barrier properties of polyvinyl ancol film by graphen oxide
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Le Ha Vu Duy and Nguyen Tuong Vy
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chemistry.chemical_compound ,Materials science ,Chemical engineering ,chemistry ,Water barrier ,Oxide ,General Medicine - Abstract
In this study, graphene oxide (GO) is synthesized by a modified Hummers method, Polyvinyl alcohol (PVA) films and PVA/ GO nanocomposite films are prepared by casting stable aqueous mixed solutions. X-ray diffraction analysis (XRD) and scanning electron microscopy (SEM) showed that there were a good compatibility and dispersion of graphene oxide (GO) on PVA matrix. In addition, nanocomposite films reinforced graphene oxide with the content of only 0.6 % phr have had 10.11% higher tensile strength, 12.24 % greater Young modulus, and significantly reduced water permeability during 4 hours of continuous immersion. Nanocomposite films maintained good thermal stability despite being added with graphene oxide, a material that is considered to have low thermal stability that easily decomposes below 200 oC, so thermal gravimetric analysis diagram (TGA) of PVA/ GO almost did not show a change compared to the neat PVA film. Initial results show that the efficiency of dispersing and reinforcing graphene oxide material on PVA resins has ameliorated the drawbacks of this polymer and contributed to extending the application of PVA in many areas. This has also reached closer to the goal of cleaning the environment by replacing non-biodegradable polymer sources with more friendly polymers.
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- 2020
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12. Functionalized Solid-Sphere PEG-b-PCL Nanoparticles to Target Brain Capillary Endothelial CellsIn Vitro
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Gabriela Québatte, Jörg Huwyler, Philip Grossen, Le-Ha Dieu, Dominik Witzigmann, and Cristina Prescianotto-Baschong
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Materials science ,Article Subject ,medicine.diagnostic_test ,Fluorescence correlation spectroscopy ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Molecular biology ,In vitro ,0104 chemical sciences ,Flow cytometry ,chemistry.chemical_compound ,Targeted drug delivery ,chemistry ,Cell culture ,lcsh:Technology (General) ,PEG ratio ,medicine ,lcsh:T1-995 ,General Materials Science ,MTT assay ,0210 nano-technology ,Ethylene glycol - Abstract
Nanoparticles are increasingly used to implement drug targeting strategies. In the present study, solid-sphere nanoparticles (SNPs) made of poly(ethylene glycol)-b-poly(ε-caprolactone) (PEG-b-PCL) were covalently linked to a monoclonal antibody (83-14 mAb) targeted against the human insulin receptor that is highly expressed on human brain microvascular endothelial cells. Resulting targeted SNPs were characterized using transmission electron microscopy (TEM), cryo-TEM, dynamic light scattering, and fluorescence correlation spectroscopy. The critical aggregation concentration was determined using a fluorescence approach. Interaction with a well-characterized humanin vitromodel of the blood-brain barrier (hCMEC/D3) was analysed using an array of methods (flow cytometry, confocal laser scanning microscopy, and TEM). The toxicity on hCMEC/D3 cells and in addition on the human liver cell line HepG2 was assessed using the MTT assay. SNPs with a diameter of 80 nm and a homogeneous size distribution were obtained. Successful conjugation of 83-14 mAb using a heterobifunctional linker resulted in 5-6 molecules of fluorescently labeled 83-14 mAb per SNP. Functionalized SNPs were taken up by hCMEC/D3 cells efficiently without showing a significant toxic effect on cells of the blood-brain barrier and HepG2 cells. These results indicate that functionalized PEG-b-PCL SNPs are a promising candidate to deliver drugs to the CNS.
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- 2016
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13. Induction, Growth and Paclitaxel Content of Needle-and Petiole-Derived Calli in Himalayan Yew (Taxus Wallichiana Zucc.) Under Light-Emitting Diodes
- Author
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Duong Tan Nhut, Phan Le Ha Nguyen, Nguyen Trinh Don, N.T.T. Hien, Nguyen Phuc Huy, Nguyen Ba Nam, Bui The Vinh, and Tran Cong Luan
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chemistry.chemical_compound ,Plant science ,biology ,Paclitaxel ,chemistry ,Callus ,Botany ,Plant Science ,Taxus wallichiana ,biology.organism_classification ,Petiole (botany) - Abstract
To achieve a better understanding of accumulation of paclitaxel and related taxanes in Himalayan yew (Taxus wallichiana Zucc.) callus mass, induction and growth of calli from needles and petioles under light-emitting diodes (LEDs) and production of paclitaxel and baccatin were investigated. Calli were induced from needles and petioles on Gamborg's B5 medium supplemented with 1 mg·l-1 kinetin and 4 mg·l-1 2,4-D under different com-binations of blue and red LEDs. Calli were further cultured in that medium under the same lighting conditions. Callus induction from needles and petioles and growth was better under blue LEDs than under red LEDs and fluorescent light. The combinations of blue and red LEDs produced variable results. The paclitaxel content of these calli was quantified by high-performance liquid chromatography. The paclitaxel content of calli derived from needles was 0.00628% and the 10-DAB (10-Deacetylbaccatin III) content was 0.00366%. The paclitaxel content of calli derived from petioles was 0.00412%, and no 10-DAB was detected.
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- 2015
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14. Eco-Friendly Coffee Waste-Based Carbon Dots Coupled to ZnBi-Layered Double Hydroxide Heterojunction: Enhanced Control of Interfacial Charge Transfer for Highly Efficient Visible-Light Catalytic Activity
- Author
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Nguyen Thi Thanh Huong, Dang Nguyen Nha Khanh, Ngo Thi Tuong Vy, Le Hai Khoa, Nguyen The Anh, Dang Vu Bao Tran, Tong Pham Phuong Thuan, Le Khue Tu, Nguyen Thanh Ha, Nguyen Ngoc Nghia, and Nguyen Thi Kim Phuong
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Chemistry ,QD1-999 - Abstract
Using a simple, low cost, and excellent efficient approach, carbon dots (CDs) were fabricated via a one-pot hydrothermal process of coffee waste. Amazingly, the combination of 2% CDs with ZnBi2O4 to form a new and excellent heterogeneous photocatalyst enabled the complete decomposition of 2, 4-dichlorophenoxyacetic acid (2, 4-D) into CO2 and H2O. The findings of this study provide a new perspective on the utilization of agricultural waste for creating products of scientific and practical significance. More than 91% of 2, 4-D (initial concentration of 30 mg/L) was completely decomposed and dechlorinated using 1.0 g/L of CDs (2%)-ZnBi2O4 at pH 4.0 after 120 min of exposure to visible light (with k = 0.0178 min−1), and more than 86% of the decomposed 2, 4-D was mineralized into CO2 and H2O. There was no sign of catalyst deactivation after four cycles of reuse, demonstrating the durability and efficiency of CDs (2%)-ZnBi2O4. The significant improvement in the photocatalytic efficiency of CDs (2%)-ZnBi2O4 compared with that of bare CDs or ZnBi2O4 is due to the formation of defects at the interfaces of the heterojunction; therefore, the movement of photogenerated electrons at the interface between the two components is rapid. The mineralization of 2, 4-D by CDs (2%)-ZnBi2O4 upon exposure to visible light is induced mainly by the photogenerated holes, followed by O2•−, and finally OH• radicals.
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- 2024
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15. High-throughput viscosity measurement using capillary electrophoresis instrumentation and its application to protein formulation
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Andrea Allmendinger, Hanns-Christian Mahler, Jörg Huwyler, Stefan Fischer, Robert Mueller, and Le-Ha Dieu
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Capillary action ,Instrumentation ,Clinical Biochemistry ,Pharmaceutical Science ,Sensitivity and Specificity ,Analytical Chemistry ,Viscosity ,Capillary electrophoresis ,Drug Discovery ,Newtonian fluid ,Spectroscopy ,Reproducibility ,Chromatography ,Rheometry ,Chemistry ,Antibodies, Monoclonal ,Electrophoresis, Capillary ,Proteins ,Reproducibility of Results ,Repeatability ,High-Throughput Screening Assays ,Solutions ,Models, Chemical ,Pharmaceutical Preparations ,Rheology - Abstract
Viscosity characterization of protein formulations is of utmost importance for the development of subcutaneously administered formulations. However, viscosity determinations are time-consuming and require large sample volumes in the range of hundreds of microliters to a few milliliters, depending on the method used. In this article, an automated, high-throughput method is described to determine dynamic viscosity of Newtonian fluids using standard capillary electrophoresis (CE) equipment. CE is an analytical method routinely used for the separation and characterization of proteins. In our set-up, the capillary is filled with the test sample, and a constant pressure is applied. A small aliquot of riboflavin is subsequently loaded into the capillary and used as a dye to monitor movement of protein samples. Migration time of the riboflavin peak moving through the filled capillary is converted to the viscosity by applying the Hagen–Poiseuille's law. The instrument is operated without using an electrical field. Repeatability, robustness, linearity, and reproducibility were demonstrated for different capillary lots and instruments, as well as for different capillary lengths and diameters. Accuracy was verified by comparing the viscosity data obtained by CE instrumentation with those obtained by plate/cone rheometry. The suitability of the method for protein formulations was demonstrated, and limitations were discussed. Typical viscosities in the range of 5–40 mPa s were reliably measured with this method. Advantages of the CE instrumentation-based method included short measurement times (1–15 min), small sample volumes (few microliters) for a capillary with a diameter of 50 μm and a length of 20.5 cm as well as potential to be suitable for high-throughput measurements.
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- 2014
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16. Preparation of silver nanoparticles by gamma Irradiation method using chitosan as stabilizer
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Thu Hong Tran, Thi Tam Tran, Tan Man Nguyen, Thi Thuy Tran, Thi Le Ha Pham, Duy Hang Nguyen, Hai Le, Xuan Cuong Le, Huu Tu Le, and Trong Hoanh Phong Nguyen
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Chitosan ,chemistry.chemical_compound ,Materials science ,chemistry ,Silver nanoparticle ,Nuclear chemistry ,Stabilizer (chemistry) ,Gamma irradiation - Abstract
Silver nanoparticles were prepared from (Ag+) aqueous solution by the method of γ-ray irradiation using chitosan as stabilizer. The saturated conversion dose (Ag+ à Ago) determined by UV-Vis spectroscopy was found to be about 16 kGy. The UV-Vis spectrum showed that an absorption peak at λmax = 400 nm due to surface plasma resonance. The image of transmission electron microscopy (TEM) showed that the silver nanoparticles were mostly spherical in shape and the average diameter was of about ~ 12 nm. The prepared colloidal silver nanoparticles solution was in good stability during storage time.
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- 2014
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17. Tin fluoride assisted growth of air stable perovskite derivative Cs2SnI6 thin film as a hole transport layer
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Pham Van Phuc, Pham Van Hoi, Le Ha Chi, Pham Duy Long, Nguyen Tien Thanh, Nguyen Thi Tu Oanh, Nguyen Tien Dai, and Thach Thi Dao Lien
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Materials science ,Polymers and Plastics ,Metals and Alloys ,chemistry.chemical_element ,Hole transport layer ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,Ambient air ,Biomaterials ,chemistry.chemical_compound ,chemistry ,Chemical engineering ,Thin film ,Tin ,Fluoride ,Derivative (chemistry) ,Perovskite (structure) - Published
- 2019
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18. Nano-porous Silicon Microcavity Sensors for Determination of Organic Fuel Mixtures
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Van Hoi Pham, Huy Bui, Le Ha Hoang, Thuy Van Nguyen, The Anh Nguyen, Thanh Son Pham, and Quang Minh Ngo
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Materials science ,Silicon ,business.industry ,Scanning electron microscope ,Hybrid silicon laser ,Transfer-matrix method (optics) ,Physics::Optics ,chemistry.chemical_element ,Porous silicon ,Evaporation (deposition) ,Atomic and Molecular Physics, and Optics ,chemistry ,Optoelectronics ,business ,Porosity ,Refractive index - Abstract
We present the preparation and characteristics of liquid-phase sensors based on nano-porous silicon multilayer structures for determination of organic content in gasoline. The principle of the sensor is a determination of the cavity-resonant wavelength shift caused by refractive index change of the nano-porous silicon multilayer cavity due to the interaction with liquids. We use the transfer matrix method (TMM) for the design and prediction of characteristics of microcavity sensors based on nano-porous silicon multilayer structures. The preparation process of the nano-porous silicon microcavity is based on electrochemical etching of single-crystal silicon substrates, which can exactly control the porosity and thickness of the porous silicon layers. The basic characteristics of sensors obtained by experimental measurements of the different liquids with known refractive indices are in good agreement with simulation calculations. The reversibility of liquid-phase sensors is confirmed by fast complete evaporation of organic solvents using a low vacuum pump. The nano-porous silicon microcavity sensors can be used to determine different kinds of organic fuel mixtures such as bio-fuel (E5), A92 added ethanol and methanol of different concentrations up to 15%.
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- 2013
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19. Synthesis, characterization and electrochemical properties of 4.8V LiNi0.5Mn1.5O4 cathode material in lithium-ion batteries
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Sergio Brutti, Nguyen Nang Dinh, Le Ha Chi, and Bruno Scrosati
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Chemistry ,Scanning electron microscope ,General Chemical Engineering ,Inorganic chemistry ,Atomic emission spectroscopy ,Energy-dispersive X-ray spectroscopy ,chemistry.chemical_element ,Ascorbic acid ,Cathode ,law.invention ,law ,Electrochemistry ,Lithium ,Inductively coupled plasma ,Wet chemistry - Abstract
In this work the synthesis of a nickel doped cubic manganese spinel has been studied for application as cathode material in secondary lithium batteries. Six different experimental approaches have been tested in order to carry out a screening of the various possible synthetic routes. The used synthetic strategies were wet chemistry (WC), solid state (SS), combustion synthesis (CS), cellulose-based sol–gel synthesis (SG-C), ascorbic acid-based sol–gel synthesis (SG-AA) and resorcinol/formaldehyde-based sol–gel synthesis (SG-RF). The goal of our study is to obtain insights about how the synthesis conditions can be modified in order to achieve a material with improved electrochemical performances in such devices, especially in high current operating regimes. The synthesized materials have been characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) with energy dispersive spectroscopy (EDS), atomic absorption, inductively coupled plasma (ICP-MS) atomic emission spectroscopy, surface area measurements and tested as high voltage cathodes in Li-ion electrochemical devices.
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- 2010
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20. HUMAN HEALTH HAZARD OF POLYCYCLIC AROMATIC HYDROCARBON IN ROAD DUST IN HA NOI METROPOLIS
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Vo Thi Le Ha
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chemistry.chemical_classification ,Road dust ,021110 strategic, defence & security studies ,0211 other engineering and technologies ,Polycyclic aromatic hydrocarbon ,02 engineering and technology ,010501 environmental sciences ,01 natural sciences ,Hazard ,Human health ,chemistry ,Environmental chemistry ,Environmental science ,0105 earth and related environmental sciences - Abstract
This study investigates PAHs content in road dust of Hanoi metropolis, Vietnam. The samples were colected from the roads around city and analyzed by gas chromatography mass spectrometry (GC/MS). The total PAHs mass concentration ranges from 33.88 μg/kg to 5588,16 μg/kg, with the mean of 356,24 μg/kg in which HMW accounted up 70 % and LMW made up 30 %. The toxic equivalence factors (TEFs), mutagenic potency equivalent factors (MEFs) and the incremental lifetime cancer risk (ILCR) methodologies were applied to evaluate human exposure to carcinogenic PAHs sources. Carcinogenic equivalents (BaP-TEQ) and mutagenic equivalents (BaP-MEQ) were calculated from the potency relative to BaP (TEF) and BaP (MEF). The value of BaP-TEQ for 8 PAHs varied from 1.13 μg/kg to 195.23 μg/kg with mean of 24.34 μg/kg, while the value of BaP-MEQ ranged 1.45 μg/kg to 123.15 μg/kg with mean of 19.96 μg/kg. Basing on ILCRs model, the total cancer risk for children and adults was up to 1.6×10-5 and 3.9×10-5, posing a moderate potential cancer risk, respectively.
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- 2018
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21. Excessive Level of Inorganic Nitrogen in Groundwater in the Intensively Farmed Areas of Northern Vietnam
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Kiyoshi Kurosawa, Do Nguyen Hai, Tran Thi Le Ha, Nguyen Huu Thanh, Trinh Quang Huy, Ho Thi Lam Tra, and Kazuhiko Egashira
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Intensive farming ,business.industry ,Soil Science ,Tropics ,Soil science ,Groundwater recharge ,δ15N ,engineering.material ,chemistry.chemical_compound ,Nitrate ,chemistry ,Agronomy ,Agriculture ,engineering ,Environmental science ,Fertilizer ,business ,Agronomy and Crop Science ,Groundwater - Abstract
Ammonium‐nitrogen (N) and nitrate‐N concentrations in groundwater were monitored at three farming villages in northern Vietnam during 2002 and 2006 with 6‐month intervals, where 380 to 420 kg/ha of chemical fertilizer N have been applied annually. With reference to the δ15N value, the source of N in the groundwater was identified as chemical fertilizer in the two villages and as animal waste and chemical fertilizer in the one village where animal waste fertilizer had been applied additionally. Ammonium‐N concentration was alarmingly higher than the drinking water standards, whereas the nitrate‐N concentration was lower. These concentrations did not increase over time. The effect of the natural groundwater recharge diluting the concentrations was considered as a potential reason, and such trends are expected to continue. Spatial variation in the ammonium‐N and nitrate‐N concentrations was recognized as being due to differences in the applied amount and the source of fertilizer N, respectively.
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- 2008
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22. Initial research of application of astaxanthin rich Haematococcus pluvialis biomass as supplenent dietary for salmon fish in Vietnam
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Le Thi Thom, Le Ha Thu, Nguyen Cam Ha, Dang Diem Hong, and Luu Thi Tam
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chemistry.chemical_compound ,Haematococcus pluvialis ,chemistry ,Astaxanthin ,Botany ,Biomass ,%22">Fish ,Biology ,biology.organism_classification - Published
- 2016
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23. Temporal and Spatial Variations of Inorganic Nitrogen Levels in Surface and Groundwater Around Hanoi, Vietnam
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Do Nguyen Hai, Kiyoshi Kurosawa, Ho Thi Lam Tra, Nguyen Tat Canh, Tran Thi Le Ha, Kazuhiko Egashira, and Nguyen Huu Thanh
- Subjects
Hydrology ,Pollution ,Denitrification ,media_common.quotation_subject ,Soil Science ,engineering.material ,chemistry.chemical_compound ,Nitrate ,chemistry ,engineering ,Environmental science ,Spatial variability ,Fertilizer ,Water pollution ,Agronomy and Crop Science ,Surface water ,Groundwater ,media_common - Abstract
Pollution of surface and groundwater by inorganic nitrogen (N) was assessed in farm villages of northern Vietnam. The pH and ammonium-N and nitrate-N concentrations were monitored at three communes near Ha Noi in the Red River Delta in March and September 2003, following monitoring in October 2002. In each monitoring time, ammonium-N concentrations exceeded the Vietnamese water standards applicable to surface and groundwater, whereas the nitrate-N concentrations were relatively low and below the corresponding standards. Neither spatial nor temporal variation was found in the ammonium-N and nitrate-N concentrations of the surface water. A temporal increase in the ammonium-N concentration was statistically confirmed in the groundwater. Intensively applied fertilizer-N and disposed animal/human wastes were thought to be sources of ammonium-N. Ammonium-N originating from those sources was seen to accumulate steadily in the groundwater through percolation from the surface water and surrounding land. A spatial variation of the nitrate-N concentration was observed in the groundwater. The nitrate-N concentration in the groundwater was particularly low in communes located in lowland areas with alluvial soils. The suppression of nitrification or promotion of denitrification was considered to be responsible for the low nitrate-N concentration. A spatial variation was also found in the groundwater pH. Therefore, variation of the pH may be linked to variation of the nitrate-N concentration in the groundwater.
- Published
- 2006
- Full Text
- View/download PDF
24. Characterization and activity of Fe-ZSM-5 catalysts for the total oxidation of phenol in aqueous solutions
- Author
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Nguyen Huu Phu, Hoang Vinh Thang, Nguyen Van Tan, Tran Thi Kim Hoa, and Pham Le Ha
- Subjects
Aqueous solution ,Chemistry ,Process Chemistry and Technology ,Inorganic chemistry ,Catalysis ,Crystallinity ,chemistry.chemical_compound ,Catalytic oxidation ,Phenol ,ZSM-5 ,Hydrogen peroxide ,Stoichiometry ,General Environmental Science - Abstract
Fe-ZSM-5 zeolites with of Si/Fe ratios varying from 40 to 200 were synthesized and characterized by IR, XRD, SEM, ESR and ion-exchange techniques. From the obtained results, it is possible to conclude that, these zeolites have a good crystallinity and that the incorporation of Fe 3+ ions into the MFI-structure depends on the Si/Fe ratios in the gel: the higher the Si/Fe ratio, the more the percentage of Fe 3+ ions is incorporated into the MFI lattice. Catalytic properties of Fe-ZSM-5 were studied in the oxidation of phenol. The reaction was performed in a static system, at the atmospheric pressure, 343 K, and with H 2 O 2 concentration, which exceeds stoichiometric concentration for complete oxidation of phenol to carbon dioxide and water. From the catalytic results, it can be concluded that framework Fe can catalyze more completely phenol oxidation than the extra-framework Fe does.
- Published
- 2001
- Full Text
- View/download PDF
25. Polymersomes conjugated to 83-14 monoclonal antibodies: in vitro targeting of brain capillary endothelial cells
- Author
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Dalin Wu, Le-Ha Dieu, Cornelia G. Palivan, Jörg Huwyler, and Vimalkumar Balasubramanian
- Subjects
medicine.drug_class ,Polymers ,Drug delivery to the brain ,Pharmaceutical Science ,In Vitro Techniques ,Blood–brain barrier ,Monoclonal antibody ,Microscopy, Electron, Transmission ,medicine ,Humans ,Receptor ,Cell Line, Transformed ,Microscopy, Confocal ,biology ,Chemistry ,Vesicle ,Antibodies, Monoclonal ,Brain ,Endothelial Cells ,General Medicine ,Flow Cytometry ,Molecular biology ,Endocytosis ,Insulin receptor ,medicine.anatomical_structure ,Polymersome ,Biophysics ,biology.protein ,Nanocarriers ,Biotechnology ,Subcellular Fractions - Abstract
The blood-brain barrier (BBB) remains an obstacle for many drugs to reach the brain. A strategy to cross the BBB is to modify nanocarrier systems with ligands that bind to endogenous receptors expressed at the BBB to induce receptor-mediated transport. The aim of the present study was to investigate the potential of polymersomes composed of the amphiphilic diblock copolymer poly(dimethylsiloxane)-block-poly(2-methyl-2-oxazoline), PDMS-b-PMOXA, for active targeting of brain capillary endothelial cells. We conjugated PDMS-b-PMOXA polymersomes to the anti-human insulin receptor antibody 83-14 and studied their uptake by brain capillary endothelial cells. Transmission electron micrography and light scattering measurements revealed the self-assembly of the block copolymers into 200 nm vesicles after extrusion. Fluorescence correlation spectroscopy was employed to calculate the number of antibodies coupled to one polymersome. Binding and uptake of the polymersomes conjugated to 83-14 mAb were studied in the human BBB in vitro model hCMEC/D3 expressing the human insulin receptor. Competitive inhibition with an excess of free 83-14 mAb demonstrated the specificity of cellular binding and uptake. Our results suggest that PDMS-b-PMOXA polymersomes conjugated to 83-14 mAb may be suitable nanocarriers for drug delivery to the brain.
- Published
- 2014
26. Colchicine suppresses atrial fibrillation in failing heart
- Author
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Chiao Po Hsu, Eric Chong, Ya Wen Hsiao, Yi Jen Chen, Shih Lin Chang, Trung Le Ha, Shuen Hsin Liu, Yenn Jiang Lin, Yao Chang Chen, Chuen Wang Chiou, Yung Nan Tsai, Rahul Singhal, Shih Ann Chen, and Li Wei Lo
- Subjects
medicine.medical_specialty ,Paclitaxel ,medicine.medical_treatment ,Intraperitoneal injection ,Blotting, Western ,Action Potentials ,Polymerase Chain Reaction ,Ion Channels ,chemistry.chemical_compound ,Enos ,Internal medicine ,Atrial Fibrillation ,medicine ,Colchicine ,Animals ,RNA, Messenger ,Protein kinase B ,PI3K/AKT/mTOR pathway ,Heart Failure ,biology ,business.industry ,Proteins ,Atrial fibrillation ,medicine.disease ,biology.organism_classification ,Disease Models, Animal ,Endocrinology ,chemistry ,Heart failure ,Collagen ,Rabbits ,Cardiology and Cardiovascular Medicine ,business ,Perfusion ,Signal Transduction - Abstract
This study aimed to investigate the mechanism by which colchicine suppresses atrial fibrillation (AF) in a rabbit heart failure (HF) model.HF was induced by coronary ligation. Using the Langendorff perfusion system, monophasic action potentials were recorded in the left atrial appendage (LAA) of normal rabbits (n=6) and HF rabbits (n=6) treated with colchicine (100 μM) followed by colchicine (100 μM) plus paclitaxel (5 μM). Collagen content and mRNA and protein expression of ion channels through the PI3K/AKT/eNOS signaling pathway were evaluated in LAA of normal rabbits (n=6) and HF rabbits treated with vehicle (n=6) or colchicine (n=6) intraperitoneal injection for 2 days. Colchicine decreased action potential duration (74.1±2.6 vs 91.8±3.3 ms, P0.001), effective refractory period, and maximum slope of the restitution curve in HF LAA. However, these effects were reversed by paclitaxel. The incidence of early afterdepolarizations, delayed afterdepolarizations, and AF inducibility was significantly lower after colchicine perfusion than at baseline or after colchicine plus paclitaxel perfusion. Cardiac function increased and LA fibrosis decreased after colchicine treatment. mRNA and protein expression of Kir2.1, Kv1.4, Kv1.5, Kv7.1, Cav1.2, and SERCA2a were upregulated after colchicine treatment, as was mRNA expression of PI3K, AKT, and eNOS.Colchicine regulates ion channel gene expression and activates the PI3K/AKT/eNOS signaling pathway in HF rabbits, which may reverse atrial remodeling and suppress AF.
- Published
- 2013
27. Hydrothermal Synthesis and Enhanced Photocatalytic Activity of TiO\(_{2}\)-Fe@CNTs Nanocomposite for Methylene Blue Degradation under Visible Light Irradiation
- Author
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Pham Duy Long, Le Ha Chi, Le Van Hong, and Nguyen Van Chuc
- Subjects
chemistry.chemical_compound ,Fuel Technology ,Materials science ,Nanocomposite ,chemistry ,Visible light irradiation ,Photocatalysis ,Energy Engineering and Power Technology ,Hydrothermal synthesis ,Degradation (geology) ,Photochemistry ,Methylene blue - Abstract
TiO2 is one of the most attractive metal oxides because of the excellent chemical and photocatalytic properties. However, a problem in the application of TiO2 is the large band gap energy of 3.2 eV, corresponding to its photocatalytic activity under UV-light irradiation of wavelengths
- Published
- 2015
- Full Text
- View/download PDF
28. Green synthesis of silver nanoparticles using Callisia fragrans leaf extract and its anticancer activity against MCF-7, HepG2, KB, LU-1, and MKN-7 cell lines
- Author
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Nguyen Lan Anh Thi, Van Mai Bay, Van Nguyen Din, Nguyen Ngoc Quyen Thi, Van Pham Vuong, Pham Thong Le Minh, and Le Hai Tu
- Subjects
biosynthesis ,plant extract ,uv–vis absorption spectrum ,surface plasmon ,nanoparticles ,Chemistry ,QD1-999 - Abstract
This article presents a simple, eco-friendly, and green method for the synthesis of silver nanoparticles (AgNPs) from AgNO3 solution utilizing an aqueous extract of Callisia fragrans leaf. The effects of C. fragrans leaf extraction conditions were evaluated. Parameters affecting the synthesis of AgNPs, such as the volume of extract, pH, temperature, and reaction time were investigated and optimized. The obtained AgNPs were analyzed by UV–Vis spectroscopy, X-ray diffraction pattern, energy-dispersive X-ray spectroscopy, field emission scanning electron microscopy, transmission electron microscopy (TEM), dynamic light scattering (DLS), and FTIR techniques. TEM and DLS analyses have shown that the synthesized AgNPs were predominantly spherical in shape with an average size of 48 nm. The zeta potential of the colloidal solution of AgNPs is −27 mV, indicating the dispersion ability of AgNPs. The results of GC–MS and FTIR analyses show the presence of biomolecules in the aqueous extract of C. fragrans leaf that acts as reducing and capping agents for the biosynthesis of AgNPs. The synthesized AgNPs demonstrate anticancer activity against MCF-7, HepG2, KB, LU-1, and MKN-7 cell lines, with inhibitory concentrations at 50% (IC50 values) of 2.41, 2.31, 2.65, 3.26, and 2.40 µg·mL−1, respectively. The obtained results in the study show that the biosynthesized AgNP from C. fragrans leaf extract can be further exploited as a potential candidate for anticancer agents.
- Published
- 2023
- Full Text
- View/download PDF
29. Investigation of Sodium Manganese Oxide Nanowires Synthesized by Hydrothermal Method for Alkaline Ion Battery
- Author
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Le Ha Chi, Do Xuan Mai, Dang Tran Chien, Nguyen Thi Tu Oanh, Hoang Vu Chung, Pham Duy Long, Ta Anh Tan, and Do Thi Phuong
- Subjects
Battery (electricity) ,Fuel Technology ,Materials science ,chemistry ,Sodium ,Inorganic chemistry ,Nanowire ,Energy Engineering and Power Technology ,chemistry.chemical_element ,Manganese oxide ,Hydrothermal circulation ,Ion - Abstract
Sodium Manganese Oxide (NaxMnO2) has attracted much attention as cathode materials for alkaline ion battery due to the ability of fast charge and discharge ion Na+, in particular in nanoscale. We report on the synthesis of NaxMnO2 nanowires via hydrothermal synthesis route from Mn2O3 and NaOH solution. The morphological observation indicates that the obtained Na0.44MnO2 nanowires with diameters of about 20-30 nm, length up to several micrometers were formed by this process. The electrochemical properties of fabricated materials were investigated by means of cyclic voltammetry technique and show that Sodium Manganese Oxide (NaxMnO2) is a promising material in the field of research and fabrication alkaline ion battery.
- Published
- 2014
- Full Text
- View/download PDF
30. 1067 GENDER DIFFERENCE IN THE RELATIONSHIP BETWEEN LONG TERM PASSIVE SMOKING EXPOSURE AND HDL-CHOLESTEROL IN LATE ADOLESCENCE
- Author
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Lawrence J. Beilin, Beth Hands, Wendy H. Oddy, Sally Burrows, Rae-Chi Huang, Trevor A. Mori, and Chi Le-Ha
- Subjects
Passive smoking ,Physiology ,business.industry ,Cholesterol ,Late adolescence ,medicine.disease_cause ,Term (time) ,chemistry.chemical_compound ,chemistry ,Internal Medicine ,Medicine ,Cardiology and Cardiovascular Medicine ,business ,Demography - Published
- 2012
- Full Text
- View/download PDF
31. Effect of Ultrasonication on Self-Assembled Nanostructures Formed by Amphiphilic Positive-Charged Copolymers and Negative-Charged Drug
- Author
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Le Hang Dang, Minh Thanh Vu, Jun Chen, Cuu Khoa Nguyen, Long Giang Bach, Ngoc Quyen Tran, and Van Thu Le
- Subjects
Chemistry ,QD1-999 - Published
- 2019
- Full Text
- View/download PDF
32. Preparation and characterization of nanostructured composite films for organic light emitting diodes
- Author
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Tran Quang Trung, Hyung Kook Kim, Tran Thi Chung Thuy, Le Ha Chi, Nguyen Nang Dinh, and Nguyen Thang Long
- Subjects
chemistry.chemical_classification ,History ,Spin coating ,Nanocomposite ,Materials science ,Photoluminescence ,business.industry ,Composite number ,Polymer ,Computer Science Applications ,Education ,chemistry ,OLED ,Optoelectronics ,Thin film ,business ,Layer (electronics) - Abstract
With the aim to improve the photonic efficiency of an organic light emitting diode (OLED) and its display duration, both the hole transport layer (HTL) and the emitting layer (EML) were prepared as nanostructured thin films. For the HTL nanocomposite films were prepared by spin coating solutions of poly(vinylcarbazole) (PVK) and PEDOT-PSS containing TiO2nanoparticles onto low resistivity ITO substrates; for the EML, TiO2-embedded MEH-PPV (MEH-PPV+nc-TiO2) conjugate polymers were spin-coated onto the HTL. OLEDs prepared from above mentioned films have the structure of multilayers such as Al/MEH-PPV+nc-TiO2/PVK+nc-TiO2/ITO and Al/MEH-PPV+nc-TiO2/PEDOT-PSS+nc-TiO2/ITO. Characterization of the nanocomposite films showed that both the I-V characteristics and the photoluminescence spectra of the nanocomposite materials were significantly enhanced in comparison to the standard polymers.
- Published
- 2009
- Full Text
- View/download PDF
33. Enhancement of current-voltage characteristics of multilayer organic light emitting diodes by using nanostructured composite films
- Author
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Nguyen Nang Dinh, Le Ha Chi, Vo-Van Truong, Tran Thi Chung Thuy, and Tran Quang Trung
- Subjects
Spin coating ,Nanocomposite ,Materials science ,business.industry ,Oxide ,General Physics and Astronomy ,Vacuum evaporation ,Indium tin oxide ,Organic semiconductor ,chemistry.chemical_compound ,chemistry ,OLED ,Optoelectronics ,Thin film ,business - Abstract
With the aim of improving the photonic efficiency of an organic light emitting diode (OLED) and its display duration, both the hole transport layer (HTL) and the emitting layer (EL) were prepared as nanostructured thin films. For the HTL, nanocomposite films were prepared by spin-coating a homogeneous solution of low molecular weight poly(4-styrenesulfonate) (PEDOT-PSS) and surfactant-capped TiO2 nanocrystals onto low resistivity indium tin oxide (ITO) substrates; for the EL, nancrystalline titatium oxide (nc-TiO2)-embedded Poly[2-methoxy-5-(2′-ethyl-hexyloxy)-1,4-phenylene vinylene] (MEH-PPV+nc-TiO2) conjugate polymers were spin-coated onto the HTL. Also, for a shallow contact of Al/LiF/MEH-PPV instead of Al/MEH-PPV a super LiF thin film was deposited onto the EL by vacuum evaporation. The resulting multilayer OLED had the following structure of Al/LiF/MEH-PPV+nc-TiO2/PEDOT-PSS+nc-TiO2/ITO. Characterization of the nanocomposite films showed that both the current-voltage (I-V) characteristics and the photoluminescent properties of the nanocomposite materials were significantly enhanced in comparison with the standard polymers. OLEDs made from these layers would exhibit a large photonic efficiency.
- Published
- 2009
- Full Text
- View/download PDF
34. Production of biodiesel from Vernicia montana Lour. oil using a co-solvent method and the subsequent evaluation of its stability during storage
- Author
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Le Hanh Ngoc Thi, Imamura Kiyoshi, Furuta Masakazu, Van Boi Luu, and Maeda Yasuaki
- Subjects
biodiesel production ,co-solvent method ,iodine value ,low energy consumption ,vernicia montana lour. oil ,Chemistry ,QD1-999 - Abstract
The costs associated with the production of biodiesel fuel (BDF) are directly affected by the nature of the feedstock material and the methods used during the production process. In Southeast Asia, many non-edible oils are used to produce BDFs, as exemplified by the recent use of the non-edible oil derived from Vernicia montana Lour. in Laos and Vietnam for the production of BDF. In this work, we developed an improved procedure for the production of BDF from Vernicia montana oil consisting of 80.3%±0.5% α-eleostearic acid moiety (C18:3) using a co-solvent method. Furthermore, the stability of the BDF was evaluated based on its iodine value and unsaturated ester content. The optimized production conditions were determined to be as follows: methanol/oil molar ratio of 6:1, 1% (wt/wt) KOH, 20% (wt/wt) acetone as a co-solvent, and a reaction temperature of 40°C. Under these conditions, we achieved a BDF conversion efficiency of 99%±0.3% within 30 min of initiating the transesterification process. Notably, the BDF produced from Vernicia montana oil showed good stability to air at temperatures ≤30°C for 1 month, showing similar stability properties to the BDF produced from rapeseed oil.
- Published
- 2018
- Full Text
- View/download PDF
35. Partical volumes in the water-acetonitrile-tetrahydrofuran system
- Author
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E.sz. Kováts and Ngoc Le Ha
- Subjects
chemistry.chemical_compound ,chemistry ,Volume (thermodynamics) ,Organic Chemistry ,Clinical Biochemistry ,Analytical chemistry ,Liquid-solid chromatography ,Atmospheric temperature range ,Acetonitrile ,Biochemistry ,Tetrahydrofuran ,Analytical Chemistry - Abstract
The necessary information is given to calculate volume fractions in binary systems formed with water, acetonitrile and tetrahydrofuran, in the temperature range 20–50°C.
- Published
- 1982
- Full Text
- View/download PDF
36. Adsorption isotherm at the liquid-solid interface and the interpretation of chromatographic data
- Author
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Ngoc Le Ha, Janos. Ungvarai, and Ervin sz. Kováts
- Subjects
Chemistry ,Interface (Java) ,Thermodynamics ,Freundlich equation ,Liquid solid ,Sorption isotherm ,Analytical Chemistry ,Interpretation (model theory) - Published
- 1982
- Full Text
- View/download PDF
37. Monofunctional (Dimethylamino)silane as Silylating Agent
- Author
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Ervin sz. Kováts, Ngoc Le Ha, Philippe Schneider, Peter Zeltner, and Katalin Szabó
- Subjects
Silanes ,Silylation ,Silicon dioxide ,Organic Chemistry ,Biochemistry ,Silane ,Catalysis ,Inorganic Chemistry ,chemistry.chemical_compound ,chemistry ,Drug Discovery ,Organic chemistry ,Thermal stability ,Physical and Theoretical Chemistry ,Layer (electronics) ,Dimethylamine - Abstract
The reaction of triorganyl(dimethylamino)silanes with surface-hydrated silicon dioxide has been studied. These silylating agents are easy to prepare from the corresponding chloro or bromosilanes with dimethylamine. The resulting products are thermally stable and relatively volatile. Reaction with surface-hydrated silicon-dioxide preparations at 150–250°C for 170 h yields a dense grafted layer. However, with (dimethylamino)silanes having strongly polar substituents, a retreatment of the surface-modified silica seems to be necessary in order to attain maximum coverage.
- Published
- 1984
- Full Text
- View/download PDF
38. ChemInform Abstract: MONOFUNCTIONAL (DIMETHYLAMINO)SILANE AS SILYLATING AGENT
- Author
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Peter Zeltner, Philippe Schneider, K. Szabo, E. Sz. Kovats, and Ngoc Le Ha
- Subjects
chemistry.chemical_compound ,chemistry ,Polymer chemistry ,General Medicine ,Silane - Published
- 1985
- Full Text
- View/download PDF
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