A Dual-phasic Carbon Composite Cathode for Lithium-Oxygen Batteries

( Pham Thi Thu Hien ),김영수,이종원,박민식 한국공업화학회 2019 한국공업화학회 연구논문 초록집 Vol.2019 No.1

Lithium-oxygen batteries have been attracting a lot of interest due to their extremely huge theoretical capacity. Lithium ion from the anode is combined with reduced oxygen and form lithium peroxide (Li₂O₂) at the cathode during the discharge. Li₂O₂ is stored there and later convert back to lithium ion and oxygen during the charge. Therefore, the cathode should have large surface area to provide abundant reaction sites and large volume to accommodate as much Li₂O₂ as possible. It also should be porous for oxygen transport facilitation and good at electric conductivity. Herein, we propose a dual-phasic carbon composite that exploits the synergy between metal-organic frameworks (MOFs) and carbon nanotubes (CNTs). The dual-phasic nanoarchitecture incorporates the advantages of both components: MOF-C provides a large surface area and a large pore volume for Li₂O₂ storage, and CNTs provide facile pathways for electron and O₂ transport as well as additional spaces for Li₂O₂ storage.

Dynamic Spectrum Access for Cognitive UAV Networks: A Review

Thi Thu Hien Pham,Sungrae Cho(조성래) 한국통신학회 2023 한국통신학회 학술대회논문집 Vol.2023 No.6

Impacts of Urban Land Cover Change on Land Surface Temperature Distribution in Ho Chi Minh City, Vietnam

Le, Thi Thu Ha,Nguyen, Van Trung,Pham, Thi Lan,Tong, Thi Huyen Ai,La, Phu Hien 한국측량학회 2021 한국측량학회지 Vol.39 No.2

A Laboratory-Scale Study of the Applicability of a Halophilic Sediment Bioelectrochemical System for in situ Reclamation of Water and Sediment in Brackish Aquaculture Ponds: Establishment, Bacterial Community and Performance Evaluation

( Hai The Pham ),( Hien Thi Tran ),( Linh Thuy Vu ),( Hien The Dang ),( Thuy Thu Thi Nguyen ),( Thu Ha Thi Dang ),( Mai Thanh Thi Nguyen ),( Huy Quang Nguyen ),( Byung Hong Kim ) 한국미생물·생명공학회 2019 Journal of microbiology and biotechnology Vol.29 No.7

In this study, we investigated the potential of using sediment bioelectrochemical systems (SBESs) for in situ treatment of the water and sediment in brackish aquaculture ponds polluted with uneaten feed. An SBES integrated into a laboratory-scale tank simulating a brackish aquaculture pond was established. This test tank and the control (not containing the SBES) were fed with shrimp feed in a scheme that mimics a situation where 50% of feed is uneaten. After the SBES was inoculated with microbial sources from actual shrimp pond sediments, electricity generation was well observed from the first experimental week, indicating successful enrichment of electrochemically active bacteria in the test tank sediment. The electricity generation became steady after 3 weeks of operation, with an average current density of 2.3 mA/㎡ anode surface and an average power density of 0.05 mW/㎡ anode surface. The SBES removed 20-30% more COD of the tank water, compared to the control. After 1 year, the SBES also reduced the amount of sediment in the tank by 40% and thus could remove approximately 40% more COD and approximately 52% more nitrogen from the sediment, compared to the control. Insignificant amounts of nitrite and nitrate were detected, suggesting complete removal of nitrogen by the system. PCR-DGGE-based analyses revealed the dominant presence of Methylophilus rhizosphaerae, Desulfatitalea tepidiphila and Thiothrix eikelboomii, which have not been found in bioelectrochemical systems before, in the bacterial community in the sediment of the SBES-containing tank. The results of this research demonstrate the potential application of SBESs in helping to reduce water pollution threats, fish and shrimp disease risks, and thus farmers’ losses.

Proposal for the development of a national open access database in Vietnam and comparison with other Asian countries’ national literature databases

Loc My Thi Nguyen,Tien-Trung Nguyen,Thanh Thi Nghiem,Hien Thu Thi Le,Thao Phuong Thi Trinh,Thuan Van Pham,Thanh Chi Nguyen,Linh Khanh Hoang,Trung Tran 한국과학학술지편집인협의회 2020 Science Editing Vol.7 No.1

In the context of the need to ensure appropriate signalling of the publication of high-quality, international-calibre publications in Vietnam, as well as new policies to improve the quality and effectiveness of scientific research in Vietnam, it is practical to investigate the possibility of developing a national open access database (NOAD). This study aims to answer the question of whether it is necessary to establish a NOAD in Vietnam. We used document analysis to evaluate issues related to NOADs. The results of this study show the complexity, lack of consistency, and difficulty in obtaining practical statistics and assessing research and scientific records in Vietnam today. Furthermore, the findings of this study imply that it is necessary to establish a NOAD of scientific research in Vietnam. The information in this report can be used to develop a NOAD for Vietnam in particular, and for any country that lacks one in general.

Culture, Leadership Practices and Organizational Commitment at Commercial Banks in Vietnam

DUONG, Thi Thu,NGUYEN, Thi Thuy Hanh,PHAM, Hien Korea Institute for ASEAN Studies 2021 Suvannabhumi Vol.13 No.1

This study attempted to investigate the effects of collectivism as an individual cultural value and leadership practices on employees' organizational commitment of six commercial banks in Vietnam. The study used collectivism and the implementation of five leadership practices as the independent variables, the three components of organizational commitment as the dependent variables and employees' personal factors served as controlling variables. The study utilized a quantitative method of research with questionnaires as the main data collection instrument. The findings of the study have revealed that the individual cultural value of collectivism positively, but to a marginal degree, affected the level of employees' organizational commitment. Among five leadership practices, only the implementation of encourage the heart, positively, but to a marginal degree, influenced employees' affective and normative commitment. The leadership practice of challenge the process had a negative impact on the employees' affective commitment. The personal factors of employees did not have an impact on organizational commitment. The findings and conclusions of this study may be used by the leaders to create the favorable working environment, improve the relationship between leaders and followers and to increase organizational commitment.

Culture, Leadership Practices and Organizational Commitment at Commercial Banks in Vietnam

( Duong Thi Thu ),( Nguyen Thi Thuy Hanh ),( Pham Hien ) 부산외국어대학교 아세안연구원(구 부산외국어대학교 동남아지역원) 2021 Suvannabhumi Vol.13 No.1

This study attempted to investigate the effects of collectivism as an individual cultural value and leadership practices on employees’ organizational commitment of six commercial banks in Vietnam. The study used collectivism and the implementation of five leadership practices as the independent variables, the three components of organizational commitment as the dependent variables and employees’ personal factors served as controlling variables. The study utilized a quantitative method of research with questionnaires as the main data collection instrument. The findings of the study have revealed that the individual cultural value of collectivism positively, but to a marginal degree, affected the level of employees’ organizational commitment. Among five leadership practices, only the implementation of encourage the heart, positively, but to a marginal degree, influenced employees’ affective and normative commitment. The leadership practice of challenge the process had a negative impact on the employees’ affective commitment. The personal factors of employees did not have an impact on organizational commitment. The findings and conclusions of this study may be used by the leaders to create the favorable working environment, improve the relationship between leaders and followers and to increase organizational commitment.

Alpha-Glucosidase Inhibitory Activity of Saponins Isolated from Vernonia gratiosa Hance

Cong Pham Van,Anh Hoang Le Tuan,Vinh Le Ba,Han Yoo Kyong,Trung Nguyen Quang,Minh Bui Quang,Duc Ngo Viet,Ngoc Tran Minh,Hien Nguyen Thi Thu,Manh Hoang Duc,Lien Le Thi,Lee Ki Yong 한국미생물·생명공학회 2023 Journal of microbiology and biotechnology Vol.33 No.6

Species belonging to the Vernonia (Asteraceae), the largest genus in the tribe Vernonieae (consisting of about 1,000 species), are widely used in food and medicine. These plants are rich sources of bioactive sesquiterpene lactones and steroid saponins, likely including many as yet undiscovered chemical components. A phytochemical investigation resulted in the separation of three new stigmastane-type steroidal saponins (1 – 3), designated as vernogratiosides A–C, from whole plants of V. gratiosa. Their structures were elucidated based on infrared spectroscopy  (IR), one-dimensional (1D) and two-dimensional nuclear magnetic resonance (2D NMR), high-resolution electrospray ionization mass spectrometry (HR-ESI-MS), and electronic circular dichroism analyses (ECD), as well as chemical reactivity. Molecular docking analysis of representative saponins with αglucosidase inhibitory activity was performed. Additionally, the intended substances were tested for their ability to inhibit α-glucosidase activity in a laboratory setting. The results suggested that stigmastane-type steroidal saponins from V. gratiosa are promising candidate antidiabetic agents.

Characterizations of hyaluronate-based terpolymeric hydrogel synthesized via free radical polymerization mechanism for biomedical applications

Das, Dipankar,Pham, Thi Thu Hien,Noh, Insup Elsevier 2018 Colloids and surfaces. B, Biointerfaces Vol.170 No.-

<P><B>Abstract</B></P> <P>In the present study, a novel terpolymeric hydrogel was developed using sodium hyaluronate (HA), 2-hydroxyethyl acrylate (2-HEA), and poly(ethylene glycol) diacrylate (PEGDA) via free radical polymerization for biomedical applications. To achieve elasticity, swelling ability, porous architecture and sufficient gel strength, hyaluronate was chemically modified by grafting and crosslinking methods using 2-HEA and PEGDA, respectively. The structure and compositions of the fabricated terpolymer (HA-g-p(2-HEA)-x-PEGDA) were verified by FTIR, <SUP>1</SUP>H HR-MAS-NMR, and TGA analyses. The surface morphology and cross-section of the hydrogel was detected by SEM analysis. The gel nature of terpolymer in aqueous medium at 37 °C was confirmed from swelling study, and rheological experiment. Non-cytotoxicity and biocompatibility of the HA-g-p(2-HEA)-x-PEGDA hydrogel were ascertained by <I>in vitro</I> mouse osteoblastic cells (MC3T3) proliferation, and viability studies. Hematoxylin and eosin Y, and Masson’s trichrome stainings were performed to show tissue regeneration ability on the prepared hydrogel. <I>In vitro</I> release results of proangiogenic drug-dimethyloxalylglycine (DMOG), and antibiotics-tetracycline (TCN) showed sustained release behaviour from the prepared hydrogel under different pHs at 37 °C. The mathematical models fitted data imply that both DMOG and TCN release follow first order kinetics, while, the release mechanism is primarily controlled by diffusion as well as erosion process. Finally, the novel biocompatible HA-g-p(2-HEA)-x-PEGDA gel, which showed sustained drugs release, and regeneration ability of extracellular matrix and collagen, could be employed in biomedical applications, especially, for the delivery of DMOG/TCN, and in tissue engineering.</P> <P><B>Highlights</B></P> <P> <UL> <LI> A hyaluronate based terpolymeric hydrogel was developed by radical polymerization. </LI> <LI> The hydrogel is biocompatible and releases DMOG, and TCN drugs in a controlled way. </LI> <LI> Extracellular matrix, and collagen were developed after 3 weeks in the gel matrix. </LI> <LI> The synthesized hydrogel could be used for small defect in bone tissue engineering. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Fabrication of alginate-based stimuli-responsive, non-cytotoxic, terpolymric semi-IPN hydrogel as a carrier for controlled release of bovine albumin serum and 5-amino salicylic acid

Das, Dipankar,Pham, Hien Thi Thu,Lee, Seongho,Noh, Insup Elsevier 2019 Materials science & engineering. C, Materials for Vol.98 No.-

<P><B>Abstract</B></P> <P>Herein, we report a functionalized alginate(Alg)-based terpolymeric semi-interpenetrating (semi-IPN) hydrogel, synthesized via free radical polymerization for the delivery of bovine albumin serum (BSA) and 5-amino salicylic acid (5-ASA). To improve mechanical properties, and to modulate surface morphology of Alg, 2-hydroxyethyl acrylate (HEA) was grafted on alginate and then crosslinked using poly(ethylene glycol) diacrylate (PEGDA). The probable structure and compositions of the synthesized semi-IPN terpolymer were identified by FTIR, <SUP>1</SUP>H-HR-MAS NMR, and TGA analyses. Achievement of equilibrium swelling state (ESS) and higher elastic modulus values confirmed terpolymer gel formation in aqueous media. Differences in the ESS of the prepared gel at pH 2.5 and 7.4 signify its stimuli-responsive behaviour. The influence of PEGDA on swelling, mechanical properties, surface morphology, cell viability and proliferation, and BSA and 5-ASA delivery were characterized. SEM images show that higher % PEGDA resulted in smaller sized pores in the gel network. Texture analyses demonstrate that hardness, adhesiveness and chewiness of the gel were enhanced at higher PEGDA concentrations. Increases in PEGDA concentration also induced increases in osteoblastic cell viability and higher rates of cell proliferation compared with gels containing lower concentrations of PEGDA. The release results indicate that the gels containing higher concentrations of PEGDA more sustainably release BSA and 5-ASA at 5 days and 30 h, respectively. The experimental data revealed that the synthesized terpolymeric semi-IPN hydrogel may have useful biomedical applications, especially as a carrier of protein (BSA), or 5-ASA (a therapeutic option for conditions of the colon such as Crohn's Disease and Ulcerative Colitis).</P> <P><B>Highlights</B></P> <P> <UL> <LI> Alginate-based terpolymeric semi-IPN gel was synthesized and analysed by controlling concentration of poly(ethylene glycol) diacrylate. </LI> <LI> Higher concentration of poly(ethylene glycol) diacrylate showed better biocompatibility. </LI> <LI> In vitro cell study showed osteoblastic cell survival and proliferation. </LI> <LI> The hydrogel releases bovine serum albumin and 5-amino salicylic acid in a sustain way. </LI> </UL> </P>