The Distribution of Information through Online Meeting after COVID-19: Examining the Effect of Past Behavior

Van Hao HOANG(Van Hao HOANG ),Van Vien VU(Van Vien VU ),Quang Truong NGO(Quang Truong NGO ) 한국유통과학회 2023 유통과학연구 Vol.21 No.8

Purpose: Online meeting is chosen instead of face-to-face conferences as a solution that ensures both effectiveness and legality during times of strong epidemic outbreaks. In the current period, managers can have different types of meeting options for information distribution. This study has examined the effect of past behavior on the managers’ intention of organizing online meetings. Research design, data and methodology: Data were collected from a survey with 475 managers and put into SmartPLS 4.0 for analysis. Partial least squares structural equation modeling (PLS-SEM) was employed to test relationships in the research model. Results: The findings indicated that past behavior plays the most critical role in explaining the organizing online meeting intention of managers, followed by attitude and subjective norms. Meanwhile, the perceived behavioral control factor has absolutely no effect on intention in the context of this study. Notably, attitude and subjective norms also remarkably mediated the impact of past behavior on managers’ intention. Conclusions: This study has added to the understanding of the meeting organization behavior of managers. Even if the epidemic is under control, the administrators should still organize some meetings in the form of online because it will affect the social perceptions of future behavior and behavioral intention.

Effects of Media on the Callogenensis and Cell Mass Production in Cell Cultures of Panax vietnamensis

Hoang Van Luong,Nguyen Van Long,Vu Binh Duong,Nguyen Linh Toan,Nguyen Van Minh,Le Bach Quang,Nam Hyuck Kim,Sang Yo Byun 한국생물공학회 2009 KSBB Journal Vol.24 No.2

This study was initiated to investigate the impacts of media types and other components on the callogenensis and cell mass production of Panax vietnamensis in the first step of the cell biomass procedure. Four media were checked: Murashige-Skoog (MS), White, Gamborg and Nitch-All. All the four media were shown potential media for Panax vietnamensis callogenensis and cell mass production, in which the MS medium showed the best results: the successful callogenensis ratio and cell mass formation were 30% and 62,93 ± 3,63 mg (DW) respectively, the Nitch medium showed the lowest results: the successful callogenensis ratio and cell mass formation were 15% and 27,10 ± 2,24 mg (DW) respectively. The results showed that the MS medium is the most suitable medium for Panax vietnamensis callogenensis and cell mass production.

Excellent detection of H₂S gas at ppb concentrations using ZnFe₂O₄ nanofibers loaded with reduced graphene oxide

Van Hoang, Nguyen,Hung, Chu Manh,Hoa, Nguyen Duc,Van Duy, Nguyen,Park, Inkyu,Van Hieu, Nguyen Elsevier Sequoia 2019 Sensors and actuators. B Chemical Vol.282 No.-

<P><B>Abstract</B></P> <P>Cost-effective fabrication of sensors and detection of ultralow concentrations of toxic gases are important concerns for environmental monitoring. In this study, the reduced graphene oxide (RGO)-loaded ZnFe<SUB>2</SUB>O<SUB>4</SUB> nanofibers (ZFO-NFs) were fabricated by facile on-chip electrospinning method and subsequent heat treatment. The multi-porous NFs with single-phase cubic spinel structure and typical spider-net morphology were directly assembled on Pt-interdigitated electrodes. The diameters of the RGO-loaded ZFO-NFs were approximately 50–100 nm with many nanograins. The responses to H<SUB>2</SUB>S gas showed a bell-shaped behaviour with respect to RGO contents and annealing temperatures. The optimal values of the RGO contents and the annealing temperatures were found to be about 1.0 wt% and 600 °C, respectively. The response of the RGO-loaded ZnFe<SUB>2</SUB>O<SUB>4</SUB> NFs to 1 ppm H<SUB>2</SUB>S gas was as high as 147 at 350°C while their cross-gas responses to SO<SUB>2</SUB> (10 ppm), NH<SUB>3</SUB> (100 ppm), H<SUB>2</SUB> (250 ppm), C<SUB>3</SUB>H<SUB>6</SUB>O (1000 ppm), and C<SUB>2</SUB>H<SUB>5</SUB>OH (1000 ppm) were rather low (1.8−5.6). The high sensor response was attributed to formation of a heterojunction between RGO and ZnFe<SUB>2</SUB>O<SUB>4</SUB> and due to the fact that NFs consisted of many nanograins which resulted in multi-porous structure and formation of potential barriers at grain boundaries.</P> <P><B>Highlights</B></P> <P> <UL> <LI> rGO-loaded ZnFe<SUB>2</SUB>O<SUB>4</SUB> nanofibers have simply prepared by electrospinning. </LI> <LI> rGO-loaded ZnFe<SUB>2</SUB>O<SUB>4</SUB> nanofiber sensors can detect H<SUB>2</SUB>S gas down to ppb level. </LI> <LI> The loading rGO can result in an enhancement of H<SUB>2</SUB>S gas ensing performance. </LI> </UL> </P>

Discovery of Conformationally Restricted Human Glutaminyl Cyclase Inhibitors as Potent Anti-Alzheimer’s Agents by Structure-Based Design

Hoang, Van-Hai,Ngo, Van T. H.,Cui, Minghua,Manh, Nguyen Van,Tran, Phuong-Thao,Ann, Jihyae,Ha, Hee-Jin,Kim, Hee,Choi, Kwanghyun,Kim, Young-Ho,Chang, Hyerim,Macalino, Stephani Joy Y.,Lee, Jiyoun,Choi, S American Chemical Society 2019 Journal of medicinal chemistry Vol.62 No.17

<P>Alzheimer’s disease (AD) is an incurable, progressive neurodegenerative disease whose pathogenesis cannot be defined by one single element but consists of various factors; thus, there is a call for alternative approaches to tackle the multifaceted aspects of AD. Among the potential alternative targets, we aim to focus on glutaminyl cyclase (QC), which reduces the toxic pyroform of β-amyloid in the brains of AD patients. On the basis of a putative active conformation of the prototype inhibitor <B>1</B>, a series of N-substituted thiourea, urea, and α-substituted amide derivatives were developed. The structure-activity relationship analyses indicated that conformationally restrained inhibitors demonstrated much improved QC inhibition in vitro compared to nonrestricted analogues, and several selected compounds demonstrated desirable therapeutic activity in an AD mouse model. The conformational analysis of a representative inhibitor indicated that the inhibitor appeared to maintain the Z-E conformation at the active site, as it is critical for its potent activity.</P> [FIG OMISSION]</BR>

Enhancing Removal of Acid Orange II by Heterogeneous Catalytic Ozonation Using ZnO Nanoparticles-Modified Fly Ash Composite

Hoang Van Hung,Chu Thi Hong Huyen,Nguyen Thi Dong,Nguyen Thi Hong Vien,Nguyen Thu Huyen,Luu Thi Cuc,Van Huu Tap,Nguyen Hoang,Duong Dinh Tuan,Nguyen Van Huu Luong 한국화학공학회 2024 Korean Journal of Chemical Engineering Vol.41 No.5

In this study, heterogeneous catalytic ozonation using fl y ash (FA) modifi ed ZnO nanoparticles to the decolorization of acid orange II (AOII) was studied. The combination of ZnO and fl y ash via an incipient wetness impregnation method to form ZOFA composites created a synergistic eff ect that led to effi cient catalytic ozonation activity towards AOII degradation and decolorization compared with individual ozonation processes. From the experimental results, ZOFA composite with the optimal weight ratio between ZnO NPs and FA was 20 wt% (denoted as ZOFA-20) that exhibited outstanding catalytic ozonation activity. Moreover, through other investigations including initial pH conditions and catalyst dosage, AOII could be eff ectively and optimally eliminated by 0.5 g of ZOFA-20 with an initial pH value of 11. The corresponding k value was measured as 0.248 min −1 with a maximum TOC removal content of 77.27%. Besides, ZOFA-20 could show high catalytic ozonation activity even at highly concentrated AOII concentrations while it could also retain its excellent stability and reusability over 5 continuous AOII removal cycles. From the experimental and electron paramagnetic resonance (EPR) results, hydroxyl radical ( · OH) was the main active species during the catalytic ozonation of AOII. The present study provides a promising approach to prepare novel composite-based fl y ash that would be applicable for removing azo dye and other dye pollutants in water via a catalytic ozonation strategy.

Consumer Behavior towards E-Commerce in the Post-COVID-19 Pandemic: Implications for Relationship Marketing and Environment

Hoang Linh DANG(Hoang Linh DANG),Nguyen Van BAO(Nguyen Van BAO),Yooncheong CHO(Yooncheong CHO) 한국유통과학회 2023 Asian Journal of Business Environment (AJBE) Vol.13 No.1

Purpose: The purpose of this research paper is to explore what factors that affect customer purchase decisions in the online environment, particularly after the COVID-19 pandemic in the case of Vietnamese customers. Research Design, Data and Methodology: To clarify which factor has the most significant impacts on online purchasing decision-making process, this study proposed a research model including factors such as customer trust, proposensity to trust, system assurance, the quality of website design, attitude, and customer satisfaction. This study collected the data via online survey. Data analysis was conducted by AMOS 25.0 using the Structural Equation Modeling (SEM) method. Result: The results of this study shows that the purchase decisions were positively affected by customers’ attitude, satisfaction, trust, and the quality of websites design. Additionally, factors such as perceived size and reputation and system assurance, have impacts on buyers’ trust, while the propensity to trust has no significant impact. Conclusion: This study provides managerial implications. The results provide which factors should be improved to foster trust, attitude, customer satisfaction, and purchase decision in the online environment. The results also provide managerial implication on marketing strategies how to enhance better relationships with customers and to consider environmental issues in the era of post COVID-19.

Effects of Media on the Callogenensis and Cell Mass Production in Cell Cultures of Panax vietnamensis

Luong, Hoang Van,Long, Nguyen Van,Duong, Vu Binh,Toan, Nguyen Linh,Minh, Nguyen Van,Quang, Le Bach,Kim, Nam-Hyuck,Byun, Sang-Yo The Korean Society for Biotechnology and Bioengine 2009 KSBB Journal Vol.7 No.4

This study was initiated to investigate the impacts of media types and other components on the callogenensis and cell mass production of Panax vietnamensis in the first step of the cell biomass procedure. Four media were checked: Murashige-Skoog (MS), White, Gamborg and Nitch-AII. All the four media were shown potential media for Panax vietnamensis callogenensis and cell mass production, in which the MS medium showed the best results: the successful callogenensis ratio and cell mass formation were 30% and 62,93 ${\pm}$ 3,63 mg (DW) respectively, the Nitch medium showed the lowest results: the successful callogenensis ratio and cell mass formation were 15% and 27,10 ${\pm}$ 2,24 mg (DW) respectively. The results showed that the MS medium is the most suitable medium for Panax vietnamensis callogenensis and cell mass production.

Effective Elimination of Charge-associated Toxicity of Low Generation Polyamidoamine Dendrimer Eases Drug Delivery of Oxaliplatin

Vo Minh Hoang Do,Long Giang Bach,Diem-Huong Nguyen Tran,Van Du Cao,Thi Nhu Quynh Nguyen,Duc Thuan Hoang,Van Cuong Ngo,Dai Hai Nguyen,Thai Thanh Hoang Thi 한국생물공학회 2020 Biotechnology and Bioprocess Engineering Vol.25 No.2

Polyamidoamine (PAMAM) dendrimer is emerging as an effective nanocarrier for delivering anticancer drugs. Still, unmodified PAMAM dendrimer is hardly used in vivo because of unsatisfied drug release, high tendency of interfering with cellular membranes, and rapid clearance by reticuloendothelial system. In this study, low generation polyamidoamine (PAMAM) dendrimer G3.0 is developed and surface modified with methoxypolyethylene glycol (PAMAM G3.0-mPEG) to overcome its limitations. Specifically, PAMAM G3.0 conjugated with mPEG at different ratios are investigated to effectively eliminate its charge-associated toxicity, in which PAMAM G3.0-mPEG- 8 is chosen for oxaliplatin (OX) loading. Results reveal that OX-loaded PAMAM G3.0-mPEG-8 has desirable size, good entrapment efficiency, and sustained release with minimum drug leakage. In addition, Resazurin assay indicates that the toxicity of loaded OX is reduced as compared to free drug but still maintain substantially anticancer activity on HeLa cells, suggesting the potential application of PAMAM G3.0-mPEG-8 for OX delivery in cancer therapy.

Factors Affecting Night-Time Economic Development: Research in Hanoi, Vietnam

Ngoc Son NGUYEN(Ngoc Son NGUYEN ),Vu Hiep HOANG(Vu Hiep HOANG ),Quoc Dung NGO(Quoc Dung NGO ),Van Hoa HOANG(Van Hoa HOANG ) 한국유통과학회 2023 Asian Journal of Business Environment (AJBE) Vol.13 No.2

Purpose: The purpose of the study is to explore the factors which influence the night-time economic development in Hanoi, Vietnam. The results can help policymakers achieve a scientific basis to plan the development of night-time economy in Hanoi. Research design, data and methodology: The research model is developed from literature review with 7 independent variables, including natural conditions and resources, infrastructure, safety, environmental issues, promotion and international integration, development of sharing economy, and institution and policy. This model is then adjusted by exploratory factors analysis to have 4 new variables: Institution and environment, Infrastructure and safety, Promotion and sharing, and Nature and resources. The model is regressed based on the data of 463 observations of night-time economy in Hanoi, Vietnam. Results: Consistent with the current literature addressing night-time economy, the results show positive impacts of all of the independent variables studied. Conclusions: It is recommended for the local authorities to strengthen advertising and promoting investment for NTE development in Hanoi city and also enhance the role of state management in NTE activities by raising awareness of the state management apparatus towards a more open-minded multi-dimensional view of the NTE, developing the NTE to overcome the barrier of thinking “if it cannot be managed, it is forbidden” in state management agencies, and defining responsibilities and authority among state management agencies in the management of NTE activities and strengthening decentralization and decentralization of powers for localities in the management and development of NTE.

Automatic Calibration of Camera and LRF based on Morphological Pattern and Optimal Angular Back-projection Error

Van-Dung Hoang,조강현 제어·로봇·시스템학회 2015 International Journal of Control, Automation, and Vol.13 No.6

Nowadays, integration systems based on cameras and LRFs have been applied in many researches on robotics, such as autonomous navigation vehicles, and intelligent transportation systems. The systems using multiple sensors usually require extracting the relative information of sensors posed, which support for processing. Therefore, the task of calibration of cameras and laser devices is very important. This paper presents an automatic calibration method for determining the relative position and direction of a camera with respect to a laser rangefinder. The calibration method makes use of depth discontinuities of calibration patterns, which emphasizes laser range-beams supporting easy automatic estimation of the occurred position of laser scans on the calibration pattern. The laser range scans are also used for estimating corresponding depth image points from the camera. Finally, the relative parameters between the camera and the laser device are discovered using the set of depth point correspondences of the LRF and the camera. This paper also presents new criterion for evaluating the error of extrinsic parameters estimation based on optimal error of angular deviation between the projection and back-projection of 3D corresponding points. The evaluation results demonstrate outperformance of this method.