Two new species of Camellia (Theaceae) from Vietnam

Lieu Thi Nguyen,Ninh Tran,Uematsu CHIYOMI,Katayama HIRONORI,Dung Van Luong,Son Thanh Hoang,Ky Danh NGUYEN,Hung Viet NGUYEN,Toan Canh THAI 한국식물분류학회 2018 식물 분류학회지 Vol.48 No.2

Two new species of Camellia (Theaceae) are described from Vietnam: Camellia vuquangensis Luong, Tran & L. T. Nguyen and Camellia hatinhensis Luong, Tran & L. T. Nguyen. The new taxa were col- lected from Vu Quang National Park in the center of Vietnam. The new finds are morphologically dissimilar to all known Camellia species. Recent Camellia discoveries have increased the number of species recorded in Viet- nam from 50 to 75, making Vietnam a center of diversity and a crucial area for more research into the diversity and distributions of Camellia.

Factors that Affect Customers Satisfaction: An Empirical Study of Export-Import Service Consultant Companies in Vietnam

LE, Thai Thanh Dat,HO, Thi Thanh Ngan,LE, Nguyen Truc Quyen,HUYNH, Thi Khanh Tuyen,NGUYEN, Minh Tri,LUU, Thi Mai Anh,HOANG, Thi Phuong Thao,NGUYEN, Trong Luan Korea Distribution Science Association 2022 The Journal of Asian Finance, Economics and Busine Vol.9 No.6

The purpose of the study is to analyze the significant impacts of expectations, performance, complaints, and fairness that affect consumer satisfaction. The methodology involves reviewing and referencing relevant literature carefully, then proposing a model for customer satisfaction. This study is empirically based on a survey with 50 respondents who work in the field of import and export in the region stretching from the north to the south of Vietnam. The sampling method used in this study is the in-depth interview method. The results show that: (1) expectation has a specific impact on customer satisfaction, (2) performance has a positive impact on customer satisfaction, and (3) complaint which is an intermediary factor between expectation, performance, and fairness has an impact on satisfaction, (4) fairness has a positive effect on satisfaction, in addition, fairness is an extremely important feature when customers choose an import-export service. Research implies that increasing expectations, performance, and fairness results in an improved customer experience and satisfaction when they use the service. It is suggested that the complaint factor continue to be studied and looked into because it still has some effect on satisfaction and is an intermediate variable that changes how the other factors relate to each other.

E-commerce Adoption in Distribution: An Empirical Study on Household Businesses in Food and Beverage Industry

NGUYEN, Xuan Truong,NGUYEN, Thai Ha,DANG, Huynh Phuong,PHAM, Thi Lan Phuong,BUI, Thi Thanh,TRAN, Nhat Minh,HUYNH, Tri An,NGUYEN, Nam Phong Korea Distribution Science Association 2022 유통과학연구 Vol.20 No.2

Purpose: This study aims to identify factors affecting the adoption of e-commerce by household businesses in Vietnam's food and beverage industry. Research design, data and methodology: The integrated TAM and TOE frameworks and ten hypotheses were developed to test the relationship between relevant factors. A cross-sectional survey was conducted to collect valid data from 992 respondents who run F&B household businesses in Vietnam. Results: The empirical research results confirm all proposed hypotheses that e-commerce adoption is affected by the perceived usefulness, the perceived ease of use, vendor support partners, social expectancy, competitive pressure, subjective norm, and household resources. Meanwhile, technical readiness, environment readiness, and organization readiness are intermediate variables that influence the implementation of e-commerce in food and beverage distribution. Conclusions: The findings suggest effective orientations to foster the food and beverage e-trading practice for household businesses in developing countries. Accordingly, to encourage private household businesses to adopt e-commerce, it is necessary to focus on improving business resources, technology readiness, environment readiness, and organization readiness through raising awareness of usefulness, benefits, perceived ease of use, and increased support of vendor partners. Future research can focus on improving the efficiency of e-commerce applications in F&B distribution for both household businesses and larger-scale enterprises.

Effects of Maleic Anhydride Grafted Ethylene/Vinyl Acetate Copolymer (EVA)on the Properties of EVA/Silica Nanocomposites

Thai Hoang,Nguyen Thuy Chinh,Nguyen Thi Thu Trang,To Thi Xuan Hang,Dinh Thi Mai Thanh,Dang Viet Hung,하창식,Maëlenn Aufray 한국고분자학회 2013 Macromolecular Research Vol.21 No.11

Ternary nanocomposites based on ethylene/vinyl acetate copolymer (EVA), maleic anhydride-grafted EVA (EVAgMA), and nanosilica were prepared in a Haake Rheomixer. The structure of the EVA/EVAgMA/silica nanocomposites was characterized by Fourier transform infrared spectroscopy and field emission scanning electron microscopy. The blending sequence was found to have a significant effect on the microstructure of EVA/EVAgMA/silica nanocomposites and the dispersion behavior of the nanosilica in the EVA matrix. The tensile properties (tensile strength and elongation at break), thermal behavior, crystalline structure and weatherability of the nanocomposites were also studied. The results showed that the above properties of the nanocomposites were enhanced remarkably using 1 wt% EVAgMA.

Self-antibacterial chitosan/Aloe barbadensis Miller hydrogels releasing nitrite for biomedical applications

Thai Thanh Hoang Thi,Binh D.T. Trinh,Phuong Le Thi,Dieu Linh Tran,박기동,Dai Hai Nguyen 한국공업화학회 2021 Journal of Industrial and Engineering Chemistry Vol.103 No.-

Because of the toxic glutaraldehyde, the chitosan-glutaraldehyde hydrogels are seriously limited inbiomedical applications. In this study, exploiting bioactive compounds of Aloe barbadensis Miller, the chitosan/Aloe barbadensis Miller-glutaraldehyde (CS/AV-GDA) hydrogels were fabricated with 4-fold lowerglutaraldehyde concentration without compromising hydrogel characteristics. The gelation time wascontrolled from a few seconds to several hours. The elastic modulus was varied from 483 to 99940 Pa. The CS/AV-GDA hydrogels could release the natural nitrite amount from 24.0 to 89.6 lM within the firsthour for antibacterial activity, then continuously deliver a few lM every next hour for cell activities. Theantibacterial test against Escherichia coli and Staphylococcus aureus revealed that the CS/AV-GDA hydrogelscould kill the planktonic bacteria 5-fold more highly than control and prevent bacteria attachmenton hydrogel surface effectively. Although the CS/AV-GDA hydrogels consumed only 0.25% glutaraldehydeconcentration, their antibacterial capacities were comparable to chitosan-only hydrogels with 2% glutaraldehyde. For cytotoxicity tests, the CS/AV-GDA hydrogels using 0.25% glutaraldehyde concentrationinduce the human dermal fibroblasts proliferation significantly. All CS/AV-GDA hydrogels with glutaraldehydecrosslinker less than 1% showed non-cytotoxicity. As a result, the new CS/AV-GDA hydrogelsmight become an attractive candidate for medicine regeneration and tissue engineering.

Correlations between abnormalities of morphological details and DNA fragmentation in human sperm

Nguyen, Hiep Tuyet Thi,Dang, Hong Nhan Thi,Nguyen, Thai Thanh Thi,Nguyen, Trung Van,Dang, Thuan Cong,Nguyen, Quoc Huy Vu,Le, Minh Tam The Korean Society for Reproductive Medicine 2022 Clinical and Experimental Reproductive Medicine Vol.49 No.1

Objective: As the associations of sperm DNA fragmentation with morphology have not been examined in detail, this study aimed to investigate the relationship between abnormalities of morphological details and DNA integrity in human sperm. Methods: In this cross-sectional study, men from infertile couples were enrolled at Hue Center for Reproductive Endocrinology and Infertility, Vietnam. Conventional semen parameters, including morphological details, were analyzed following the World Health Organization 2010 criteria. Sperm DNA fragmentation was evaluated using a sperm chromatin dispersion assay. The relationships and correlations between semen parameters, sperm morphology, and the type of halosperm and the DNA fragmentation index (DFI) were analyzed. Results: Among 130 men in infertile couples, statistically significant differences were not found in the sperm halo type between the normal and abnormal sperm morphology groups. The percentage of round-head spermatozoa was higher in the DFI >15% group (16.98%±12.50%) than in the DFI ≤15% group (13.13% ±8.82%), higher values for amorphous heads were found in the DFI >15% group, and lower values for tapered heads were observed in the DFI ≤15% group; however, these differences were not statistically significant. Small-halo sperm and the DFI were positively correlated with round-head sperm (r=0.243, p=0.005 and r=0.197, p=0.025, respectively). Conclusion: The rate of general sperm morphological abnormalities in semen analysis was not related to sperm DNA integrity. However, round sperm heads were closely associated with sperm DNA fragmentation.

Aluminum in rocks: Optimized microwave-assisted acid digestion and UV-Vis spectrophotometric measurement

Nguyen Thanh-Nho,Thai Huynh-Thuc,Le-Thi Anh-Dao,Do Minh-Huy,Le-Thi Huynh-Mai,Le Quang-Huy,Nguyen-Thi Kim-Sinh,Nguyen Cong-Hau 한국분석과학회 2023 분석과학 Vol.36 No.5

Aluminium (Al) is one of the major elements in rocks and its concentration can be varied, depending on different rock types as well as sources. The present study aimed to propose an analytical method based on the UV-Vis as a cheap, simple, and common instrument equipped in most laboratories for Al quantification in rocks after the microwave assisted acid digestion. The aluminone and 8-hydroxyquinoline were investigated for the colorimetric assay. The results show that the 8-hydroxyquinoline reagent was more favorable in terms of the minimized affects of the potential interferences present in the digested solutions, i.e., Fe3+, Si4+ and F–. The calibration curve was constructed from 0.10 mg/L to 3.00 mg/L with the goodness of linearity (R2 = 0.9996). The limits of detection and quantification (LOD and LOQ) were estimated, i.e., 0.029 mg/L and 0.087 mg/L, respectively. The 8-hydroxyquinoline was applied to real rock samples, demonstrating favorable precision (RSD = 0.34 %-1.8 %) and no remarkable differences were found compared to the inductively coupled plasma-mass spectrometry (ICP-MS) as a reference measurement approach.

E-commerce Adoption in Distribution: An Empirical Study on Household Businesses in Food and Beverage Industry

Xuan Truong NGUYEN,Thai Ha NGUYEN,Huynh Phuong DANG,Thi Lan Phuong PHAM,Thi Thanh BUI,Nhat Minh TRAN,Tri An HUYNH,Nam Phong NGUYEN 한국유통과학회 2022 유통과학연구 Vol.20 No.2

Purpose: This study aims to identify factors affecting the adoption of e-commerce by household businesses in Vietnam s food and beverage industry. Research design, data and methodology: The integrated TAM and TOE frameworks and ten hypotheses were developed to test the relationship between relevant factors. A cross-sectional survey was conducted to collect valid data from 992 respondents who run F&B household businesses in Vietnam. Results: The empirical research results confirm all proposed hypotheses that e-commerce adoption is affected by the perceived usefulness, the perceived ease of use, vendor support partners, social expectancy, competitive pressure, subjective norm, and household resources. Meanwhile, technical readiness, environment readiness, and organization readiness are intermediate variables that influence the implementation of e-commerce in food and beverage distribution. Conclusions: The findings suggest effective orientations to foster the food and beverage e-trading practice for household businesses in developing countries. Accordingly, to encourage private household businesses to adopt e-commerce, it is necessary to focus on improving business resources, technology readiness, environment readiness, and organization readiness through raising awareness of usefulness, benefits, perceived ease of use, and increased support of vendor partners. Future research can focus on improving the efficiency of e-commerce applications in F&B distribution for both household businesses and larger-scale enterprises.

Enhanced electrosorption of NaCl and nickel(II) in capacitive deionization by CO2 activation coconut-shell activated carbon

Huynh Le Thanh Nguyen,Tran Thanh Nhut,Ho Thi Thanh Nguyen,Le Xuan Hoa,Le Viet Hai,Nguyen Thai Hoang 한국탄소학회 2022 Carbon Letters Vol.32 No.6

Enhancing the capacitive deionization performance requires the inner structure expansion of porous activated carbon to facilitate the charge storage and electrolyte penetration. This work aimed to modify the porosity of coconut-shell activated carbon (AC) through CO2 activation at high temperature. The electrochemical performance of CO2-activated AC electrodes was evaluated by cyclic voltammetry, charge/discharge test and electrochemical impedance spectroscopy, which exhibited that AC-800 had the superior performance with the highest capacitance of 112 F/g at the rate of 0.1 A/g and could operate for up to 4000 cycles. Furthermore, in the capacitive deionization, AC-800 showed salt removal of 9.15 mg/g with a high absorption rate of 2.8 mg/g min and Ni(II) removal of 5.32 mg/g with a rate close to 1 mg/g.min. The results promote the potential application of CO2-activated AC for desalination as well as Ni-removal through capacitance deionization (CDI) technology.

Development of label-free electrochemical lactose biosensor based on graphene/poly(1,5-diaminonaphthalene) film

Binh Hai Nguyen,Binh Thanh Nguyen,Hanh Van Vu,Chuc Van Nguyen,Dzung Tuan Nguyen,Loc Thai Nguyen,Thu Thi Vu,Lam Dai Tran 한국물리학회 2016 Current Applied Physics Vol.16 No.2

In this work, a lactose biosensor was developed by co-immobilizing b-galactosidase (b-Gal) and glucose oxidase (GOx) on microelectrodes pre-modified with Pt/graphene/P(1,5-DAN) for estimation of lactose in dairy products to prevent lactose intolerance. The Pt microelectrode was modified with graphene and 1,5-polydiaminonaphthalene film. Graphene was synthesized by chemical vapor deposition on copper tape and manually transferred to the electrode surface. Polymeric P(1,5-DAN) was grafted on top of the graphene film by electropolymerization. Modified surface of the electrode was characterized by Raman spectra analysis, FE-SEM, AFM and cyclic voltammetry. The results indicated that deposition graphene film on electrode surface induced considerable enhancement in current signal, over 20 times as high as the uncoated electrode surface. The developed sensor was successfully used to determine lactose in model samples with sensitivity, correlation coefficient (R2) and limit of detection (LOD) estimated to be 1.33 mA/(mgml1), 0.995 and 1.3 mg/ml, respectively. The combined graphene and conductive P(1,5-DAN) could serve as a novel sensing platform on electrochemical sensors with superior sensitivity.