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Nguyen Van Quy,Tran Minh Hung,Trinh Quang Thong,Le Anh Tuan,Tran Quang Huy,Nguyen Duc Hoa 한국물리학회 2013 Current Applied Physics Vol.13 No.8
The controlled synthesis of mesoporous silica and metal oxide nanocomposites with a highly ordered porous structure and large specific surface area for specific applications has been an attractive topic in the field of porous materials. Herein, we introduce a novel method for the fabrication of highly ordered mesoporous structured and large specific surface area Fe2O3/SiO2 nanocomposites, and consider their application in room temperature gas sensors. The mesoporous Fe2O3/SiO2 nanocomposites were synthesised by a two-step method, which combines the hydrothermal growth of Fe2O3 nanoparticles and the microemulsion phase of Brij 56 (C16EO10) surfactant as templates in instantly direct-templating synthesis. This synthesis method enables the fabrication of mesoporous Fe2O3/SiO2 nanocomposites without distortion of the ordered porous structure after calcination at high temperature. The synthesised materials were found to be efficient in a room temperature VOC sensor application, with good recovery.
Hoa Thi Tran,Giang Thu Nguyen,Hong Ha Thi Nguyen,Huyen Thi Tran,Quang Hong Tran,Quang Ho Tran,Ngoc Thi Ninh,Phat Tien Do,Ha Hoang Chu,Ngoc Bich Pham 한국균학회 2022 Mycobiology Vol.50 No.5
Endophytic fungi are promising sources for the production of podophyllotoxin-an important anticancer compound, replacing depleted medical plants. In this study, the endophytes asso- ciated with Dysosma difformis-an ethnomedicinal plant species were isolated to explore novel sources of podophyllotoxin. Fifty-three endophytic fungi were isolated and identified by morphological observation and ITS-based rDNA sequencing, assigning them to 27 genera in 3 divisions. Fusarium was found the most prevalent genus with a colonization frequency of 11.11%, followed by Trametes (9.26%) and Penicillium (7.41%). Phylogenetic trees were constructed for the endophytic fungi community in two collection sites, Ha Giang and Lai Chau, revealing the adaptation of the species to the specific tissues and habitats. Cytotoxic activity of endophytic fungal extracts was investigated on cancer cell lines such as SK-LU-1, HL-60, and HepG2, demonstrating strong anti-cancer activity of six isolates belonging to Penicillium, Trametes, Purpureocillium, Aspergillus, and Ganoderma with IC50 value of lower than 10 mg/mL. The presence of podophyllotoxin was indicated in Penicillium, Trametes, Aspergillus and for the first time in Purpureocillium and Ganoderma via high-performance liquid chromatography, which implied them as a potential source of this anti- cancer compound.
Nguyen, Van Quang,Baynosa, Marjorie Lara,Nguyen, Van Hoa,Tuma, Dirk,Lee, Yong Rok,Shim, Jae-Jin Elsevier 2019 APPLIED SURFACE SCIENCE - Vol.486 No.-
<P><B>Abstract</B></P> <P>Metal oxide/graphene photocatalysts have been attracting considerable attention in solving environmental pollution problems because of the limitations of the semiconductor-based photocatalysts. In this study, highly efficient and inexpensive zinc oxide (ZnO) nanoparticles with three different morphologies, such as nanospheres, nanodisks, and nanorods, anchored on reduced graphene oxide (RGO) were synthesized in solvent mixtures with different ethanol to water ratios. Among the three morphologies, the nanospherical ZnO/RGO (sZG) composite exhibited the highest methylene blue (MB) and rhodamine B removal efficiencies at 99% and 98%, respectively, after only 60 min under low-power (40 W) ultraviolet irradiation at a low catalyst loading of 0.1 g L<SUP>−1</SUP>. This nanocomposite also showed excellent photocatalytic stability under UV irradiation, retaining 96% efficiency even after 15 cycles of MB degradation. Moreover, the sZG composite exhibited a high MB degradation efficiency of approximately 99% after 100 min at a low catalyst loading of 0.2 g L<SUP>−1</SUP> under solar light illumination. The excellent photocatalytic performance and high stability of this low-cost nanospherical ZnO/RGO composite exemplarily highlights the potential of sustainable next-generation photocatalysis for treating wastewater containing organic pollutants.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Size/morphology of ZnO particles were controlled by the water-ethanol solvent ratio </LI> <LI> The critical roles of ZnO seed and HMTA in forming the particles were investigated. </LI> <LI> Catalytic performance was controlled by the morphology of ZnO nanoparticles and RGO </LI> <LI> Nanospherical ZnO/RGO showed an excellent MB photodegradation efficiency of 99%. </LI> <LI> Nanospherical ZnO/RGO exhibited a remarkable stability (96% after 15 cycles). </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>
HOA, Nguyen Dinh,NGAN, Pham Thi Hong,QUANG, Nguyen Minh,THANH, Vu Ba,QUYEN, Huynh Vo Thuc Korea Distribution Science Association 2020 The Journal of Asian Finance, Economics and Busine Vol.7 No.8
The study examines the impact of organizational rewards, procedure justice, and perceived supervisor support on perceived organizational support, and examine the impact of perceived organizational support on affective commitment to the organization in the logistic enterprises as well. Quantitative research is applied to measure relationships by regression analysis with SPSS. The research data was collected by convenient method from 180 employees who work in different departments in the logistics industry. The study results in the model 1 found that organizational rewards, procedure justice, and perceived supervisor support have a positive relationship to the perceived organizational support. The study results in the model 2 also found that perceived organizational support has strong impact on the affective commitment to the organization. The study results contribute to both management theory and management practice. For the management theory aspect, the authors suggest that perceived organizational support should be considered the key antecedent of affective commitment about which researchers should pay more attention as a concept. Based on the research results, the authors also recommend for the management practice that managers should pay attention to the implementation of rewards, procedure justice, and supervisor support to increase the perceived organizational support and affective commitment in the logistic enterprises.
Nguyen Duc Cuong,Tran Thai Hoa,Dinh Quang Khieu,Nguyen Duc Hoa,Nguyen Van Hieu 한국물리학회 2012 Current Applied Physics Vol.12 No.5
The development of a low cost and scalable gas sensor for the detection of toxic and flammable gases with fast response and high sensitivity is extremely important for monitoring environmental pollution. In this work, we introduce two different synthesis pathways for the preparation of scalable Fe2O3nanoparticles for gas sensor applications. One is co-precipitation and the other is hydrothermal method. The gas sensing properties of the a-Fe2O3 nanoparticles (NPs) fabricated by different synthesis pathways were studied and compared. The performance of the NPs in the detection of toxic and flammable gases such as carbon dioxide, ammonia, liquefied petroleum gas, ethanol, and hydrogen was evaluated. The Fe2O3 NP-based gas sensors exhibited high sensitivity and a response time of less than a minute to analytic gases. However, the NPs fabricated by the one-step direct method exhibited higher sensitivities than those generated by the a-Fe2O3 NPs obtained by co-precipitation synthesis possibly because of their nanoporous structure. This performance is attributed to the large specific surface area of the NPs, which results in higher sensitivity. The development of a low cost and scalable gas sensor for the detection of toxic and flammable gases with fast response and high sensitivity is extremely important for monitoring environmental pollution. In this work, we introduce two different synthesis pathways for the preparation of scalable Fe2O3nanoparticles for gas sensor applications. One is co-precipitation and the other is hydrothermal method. The gas sensing properties of the a-Fe2O3 nanoparticles (NPs) fabricated by different synthesis pathways were studied and compared. The performance of the NPs in the detection of toxic and flammable gases such as carbon dioxide, ammonia, liquefied petroleum gas, ethanol, and hydrogen was evaluated. The Fe2O3 NP-based gas sensors exhibited high sensitivity and a response time of less than a minute to analytic gases. However, the NPs fabricated by the one-step direct method exhibited higher sensitivities than those generated by the a-Fe2O3 NPs obtained by co-precipitation synthesis possibly because of their nanoporous structure. This performance is attributed to the large specific surface area of the NPs, which results in higher sensitivity.
Crystallization, Magnetic and Magnetoimpedance Properties of a Fe84.5Zr2Nb4B8.5Cu1 NANOPERM Ribbon
Quang Hoa Nguyen,Van Son Dang,유성초,정진수,Chau NGUYEN,이복희 한국물리학회 2008 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.52 No.5
An amorphous ribbon of Fe84:5Zr2Nb4B8:5Cu1 has ben prepared by single-rol melt spinning in an Ar atmosphere. The crystalization proces studied by dierential scanning calorimetry (DSC) isinagrementwiththatintheKisingermodelandtheJohnson-Mehl-Avrami(JMA)model. The magnetoimpedance ratio (MIR) of the ribbon has ben measured to investigate the in uence of the structural transformation in the crystalization proces and the changes of the soft magnetic propertiesafterthermaltreatment. Themagnetoimpedance(MI)ofthesesampleshasbenstudied in the frequency range from 1 MHz to 5 MHz by varying a dc magnetic eld within 300 Oe. A maximum MI ratio of up to 85 % has ben observed for ribbons annealed at 530 C for 40 min around a frequency of 1 MHz. The incremental permeability ratio (PR) shows drastic changes in soft magnetic properties as a function of the annealing temperature.
Anh-Tuan Le,Nguyen Duy Ha,Chong-Oh Kim,Jang-Roh Rhee,Nguyen Chau,Nguyen Quang Hoa,Nguyen Duc Tho,Heebok Lee 한국자기학회 2006 Journal of Magnetics Vol.11 No.1
The effect of annealing temperature on the permeability and giant magneto-impedance (GMI) behaviors of Fe68.5Mn5Si13.5B9Nb₃Cu₁ amorphous alloy has been systematically investigated. The nan℃rystalline Fe68.5Mn5- Si13.5B9Nb3Cu1 alloys consisting of ultra-fine (Fe,Mn)₃Si grains embedded in an amorphous matrix were obtained by annealing their precursor alloy at the temperature range from 500℃ to 600℃ for 1 hour in vacuum. The permeability and GMI profiles were measured as a function of external magnetic field. It was found that the increase of both the permeability and the GMI effect with increasing annealing temperature up to 535℃ was observed and ascribed to the ultrasoft magnetic properties in the sample, whereas an opposite tendency was found when annealed at 600℃ which is due to the microstructural changes caused by high-temperature annealing. The study of temperature dependence on the permeability and GMI effect showed some insights into the nature of the magnetic exchange coupling between nan℃rystallized grains through the amorphous boundaries in nan℃rystalline magnetic materials.
( Nguyen Thai Son ),( Vu Thi Thu Huong ),( Vu Thi Kim Lien ),( Do Thi Quynh Nga ),( Tran Thi Hai Au ),( Tang Thi Nga ),( Le Nguyen Minh Hoa ),( Tran Quang Binh ) 한국미생물생명공학회(구 한국산업미생물학회) 2019 Journal of microbiology and biotechnology Vol.29 No.9
The extensive distribution of multidrug-resistant (MDR) methicillin-resistant Staphylococcus aureus (MRSA) poses a threat to healthcare worldwide. This study aimed to investigate the MDR and molecular patterns of MRSA isolates in children admitted to the two biggest tertiary care pediatric hospitals in northern and southern Vietnam. A total of 168 MRSA strains were collected to determine antibiotic susceptibility by minimum inhibitory concentration tests. Antibiotic-resistant genes, pulsed-field gel electrophoresis, staphylococcal cassette chromosome mec (SCCmec) typing, and multilocus sequence typing were used for the molecular characterization of MRSA. Among the total strains, the MDR rate (51.8%) was significantly higher in the northern hospital than in the southern hospital (73% vs. 39%, p < 0.0001). The MDR-MRSA with the highest rates were “ciprofloxacin-erythromycin-gentamicin-tetracyclines” (35.6%), followed by “erythromycin-tetracycline-chloramphenicol” (24.1%), and “ciprofloxacin-erythromycin-gentamicin” (19.5%), showing an accumulative total of 79.3%. The most susceptible antibiotics were rifampicin (100%) and vancomycin (100%), followed by doxycycline (94.0%), meropenem (78.0%), and cefotaxime (75.0%). The SCCmecII strains showed greater resistance to gentamicin, ciprofloxacin, tetracycline, meropenem and cephalosporins compared with the other strains. The SCCmecII strains exhibited the highest rate in the tested genes (aacA/aphD: 55.2%, ermA/B/C: 89.7%, and tetK/M: 82.8%). ST5-SCCmecII was the predominant clone in the northern hospital, whereas SCCmecIVa was more pronounced in the southern hospital. In conclusion, our results raised concerns about the predominant MDR-MRSA strains in the pediatric hospitals in Vietnam. The north-south difference in the antibiotic resistance patterns and genetic structure of MRSA suggests different MRSA origins and various uses of antimicrobial agents between the two regions.