Ampicillin adsorption onto amine-functionalized magnetic graphene oxide: synthesis, characterization and removal mechanism

Hoang Thu Ha,Tran Dinh Minh,Ha Minh Nguyet,Ajit Kumar Sharma 한국화학공학회 2021 Korean Journal of Chemical Engineering Vol.38 No.1

There are various chemical, physical and biological methods that have been applied to remove antibiotic residuals from aqueous environment. We investigated the removal of ampicillin (AMP) by a novel nanometer-size Fe3O4/graphene oxide/aminopropyltrimethoxysilane (FGOA). Based on the sol-gel method, the graphene oxide (GO) was first modified by aminopropyltrimethoxysilane (APTMS) to form GOA material containing both acidic and basic surface functional groups. The nanomagnetic iron oxide was then decorated to the GOA surface at various weight ratios by ultra-sonication in ethanol, resulting in different FGOA samples. The as-synthesized FGOA had single-layer structure and parallel array-like well-distributed Fe3O4. In laboratory-scale, the AMP treatment efficiency by FGOA with the ratio of Fe3O4 :GOA as 1 : 5 ratio reached the highest value around 94% within 100 min and only lost 1% after five regeneration cycles. The maximum adsorption capacity of FGOA was 294mg g1, significantly much higher than the previously published materials applied to AMP uptake. Interestingly, the optimum pH of FGOA ranged extensively from 4 to 9, revealing high application potential to real wastewater without any pH adjustment. The reasonable mechanism might be mainly attributed to electrostatic attraction, hydrophilic, and π-π interaction.

Personality, Behavior, and Performance of Platform Workers: Evidence from Vietnam

Nguyet Nguyen,Thi Hoang Ha Tran The International Academy of Global Business and T 2023 The International Academy of Global Business and T Vol.19 No.5

Purpose - Based on personality - job fit theory (Kristof-Brown, 2006) and social exchange theory (Blau, 2017) we explaine evidence of the relationship between proactive personality, proactive feedback seeking behavior, and the job performance of platform workers. We also examine the moderating role of perceived organizational support in relationship between proactive personality and feedback seeking behavior and job autonomy as a moderating role between the proactive feedback seeking behavior and job performance of platform workers. Design/Methodology/Approach - This study follows structural equation modeling following a partial least square method on a sample group of 171 platform workers selected by convenient random sampling techniques and analyzed by SmarlPLS 4.0 to test research hypotheses. Findings - Research findings show that proactive personality plays an important role in promoting proactive behavior seeking feedback and job performance, and affirms the positive moderating role of perceived platform support between feedback seeking behavior and proactive personality. The study also confirmed that proactive feedback seeking behavior has a direct and indirect impact on the performance of platform workers, and this relationship is further strengthened in conditions of highly autonomous work. Research Implications - Some implications of human resource management on digital labor platforms are also proposed to improve the efficiency of human resource management.

Phylogenetic implication of seed coat sculpturing in subtribe Agrimoniinae (Rosaceae)

정경숙,Nguyet Hoang,Wayne Elisens,오병운 한국식물분류학회 2012 식물 분류학회지 Vol.42 No.4

Seed morphology in the subtribe Agrimoniinae (Rosaceae) was examined using scanning electron microscopy to identify distinct characters and evaluate their evolution in a phylogenetic framework for five genera in the subtribe: Agrimonia L., Aremonia Neck. ex Nestl., Hagenia J.F. Gmel., Leucosidea Eckl. & Zeyh., and Spenceria Trimen. All genera have one or two mature achenes in a fruiting hypanthium. In the seed coats, the cell shape, size, wall features, and sculpturing vary across genera. Of most significance is the presence of papillae structures in both Agrimonia and Aremonia. Through the mapping of papillae features onto phylogenetic trees, either one or two changes in seed coats are hypothesized. The phylogenetic tree inferred from four nuclear and six chloroplast regions of sequence data suggests that at least two steps of papillae sculpturing on seed coats are required. On the other hand, in the phylogenetic tree of a low-copy nuclear gene, one independent evolutionary step is postulated to explain the current character states. In the latter hypothesis, the seed coat sculpturing also supports a monophyletic relationship for cosmopolitan Agrimonia and European endemic Aremonia. The seed coat sculpturing provides valuable information for inferring phylogenetic relationships at the generic level in the subtribe Agrimoniinae.

Camellia tuyenquangensis (Theaceae), a new species from Vietnam

Ninh Nguyet Hai Le,Chiyomi Uematsu,Hironori Katayama,Lieu Thi Nguyen,Ninh Tran,Dung Van Luong,Son Thanh Hoang 한국식물분류학회 2017 식물 분류학회지 Vol.47 No.2

Camellia tuyenquangensis (Theaceae), a new yellow species of camellia from the Chiem Hoa district of the Tuyen Quang province in Vietnam, is described and illustrated. Camellia tuyenquangensis is similar to Camellia luongii but different from the latter species in several morphological features: leaves oblong-ovate to narrow elliptic; flowers 1–2; bracteoles glabrous on both sides; sepal margins ciliate; style cleft one half of the length. The morphological data provisionally support its placement in Camellia sect. Chrysantha Chang.

Crowdshippers’ intentions to continue participating in last-mile delivery: A study in Vietnam

Nguyen Nguyet,Tran Thi Hoang Ha,Luu Thi Thuy Duong,Vu Tuan Duong 한국해운물류학회 2023 The Asian journal of shipping and Logistics Vol.39 No.3

The growth of last-mile delivery in developing countries is featuring the important contribution of crowdshippers. Therefore, exploring the factors affecting the intentions to stay in jobs of the crowdshippers is of great significance to maintain and sustainably develop the last-mile delivery service. Based on the Social Exchange Theory, we hypothesize that benefits (economic benefits, professional reputation, and job autonomy) and costs (risks and stress at work) have an effect on crowdshippers’ intentions to continue participating in last-mile delivery service in Vietnam. We also look for differences in motivations to stay in job between full-time and part-time workers. Survey data from 428 crowdshippers were analyzed using SmartPLS. The research findings indicate that economic benefits and work autonomy (benefits) have positive influences on intention to continue participating in crowd logistics, while risks and job stress (cost) have negative effects on the intention of crowsdhippers to continue their work. In addition, research findings also uncover that differences in motivation (perception of benefits and costs) to stay in job between full-time and part-time workers also affect their intentions. Although reputation did not show a significant impact on the crowdshippers’ intentions to continue participating in crowd logistics, it was discovered that reputation has a positive effect on full-time crowdshippers’ intentions to continue working. Based on the findings of this study, we recommend that businesses increase benefits and reduce costs in job to sustain and increase the continued participation in last-mile delivery.

Investigation on optical absorption of neutral bis(1,3-diisopropyl imidazoline-2,4,5-trithione) platinum(II) complexes: A density functional theory approach

( Luong Xuan Hoang ),( Nguyet Pham ),이승걸 한국공업화학회 2022 한국공업화학회 연구논문 초록집 Vol.2022 No.-

Improvement of Anthocyanin Encapsulation Efficiency into Yeast Cell by Plasmolysis, Ethanol, and Anthocyanin Concentration Using Response Surface Methodology

( Lieu My Dong ),( Hoang Thi Thuy Hang ),( Nguyen Huyen Nguyet Tran ),( Dang Thi Kim Thuy ) 한국미생물 · 생명공학회 2020 한국미생물·생명공학회지 Vol.48 No.3

Anthocyanins are antioxidant compounds susceptible to environmental factors. Anthocyanin encapsulation into yeast cells is a viable solution to overcome this problem. In this study, the optimal factors for anthocyanin encapsulation were investigated, including anthocyanin concentration, plasmolysis contraction agent, and ethanol concentration, and response surface methodology was evaluated, for the first time. Anthocyanin from Hibiscus sabdariffa L. flowers was encapsulated into Saccharomyces cerevisiae using plasmolysis contraction agent (B: 3%-20% w/v), ethanol concentration (C: 3%-20% v/v), and anthocyanin concentration (A: 0.15-0.45 g/ml). The encapsulation yield and anthocyanin loss rate were determined using a spectrometer (520 nm), and color stability evaluation of the capsules was performed at 80℃ for 30 min. The results of the study showed that these factors have a significant impact on the encapsulation of anthocyanin, in which ethanol agents have the highest encapsulation yield compared to other factors in the study. Statistical analysis shows that the independent variables (A, B, C), their squares (A², B², C²), and the interaction between B and C have a significant effect on the encapsulation yield. The optimized factors were anthocyanin, 0.25 g/ml; NaCl, 9.5% (w/v); and ethanol, 11% (v/v) with an encapsulation yield of 36.56% ± 0.55% and anthocyanin loss rate of 15.15% ± 0.98%; This is consistent with the expected encapsulation yield of 35.46% and loss rate of 13.2%.

Does Financial Integration Matter for Financial Development? Evidence from the East Asian and Pacific Region

Farhad Taghizadeh-Hesary,Nguyet Thi Minh Phi,Hanh Hoang Thi Hong,Vu Tuan Chu 세종대학교 경제통합연구소 2019 Journal of Economic Integration Vol.34 No.4

This paper assesses the impact of financial integration on financial development and establishes thresholds for materializing gains of financial advances from financial globalization using a sample of 34 countries from the East Asian and Pacific region. Following the approaches of Kose et al. (2011) and Asongu and De Moor (2016), we test non-linearity within the financial openness and financial development nexus through semi-parametric ordinary least-squares regression, and then, we develop threshold dynamics models. According to our findings, the effect of financial integration on financial development significantly changes across different financial inflows. When using external debt as a proxy for financial openness, there exists a robust significant inverted U-shaped relationship between financial integration and financial development. The empirical findings also suggest that the financial integration-development nexus is contingent on the level of trade openness, national income, and institutional quality. The results are robust to different measures of financial development and integration, the inclusion of other determinants of financial development, and considerations of endogeneity.

GPCRs GPCRs and G Proteins: Emerging Molecular Targets for Cancer Chemoprevention

HA Ji Hee,JAYARAMAN Muralidharan,HOANG Nguyet N,DHANASEKARAN Danny N. 大韓藥學會 2011 大韓藥學會 總會 및 學術大會 Vol.2011 No.2

Metagenomic analysis of bacterial community structure and diversity of lignocellulolytic bacteria in Vietnamese native goat rumen

Do, Thi Huyen,Dao, Trong Khoa,Nguyen, Khanh Hoang Viet,Le, Ngoc Giang,Nguyen, Thi Mai Phuong,Le, Tung Lam,Phung, Thu Nguyet,Straalen, Nico M. van,Roelofs, Dick,Truong, Nam Hai Asian Australasian Association of Animal Productio 2018 Animal Bioscience Vol.31 No.5

Objective: In a previous study, analysis of Illumina sequenced metagenomic DNA data of bacteria in Vietnamese goats' rumen showed a high diversity of putative lignocellulolytic genes. In this study, taxonomy speculation of microbial community and lignocellulolytic bacteria population in the rumen was conducted to elucidate a role of bacterial structure for effective degradation of plant materials. Methods: The metagenomic data had been subjected into Basic Local Alignment Search Tool (BLASTX) algorithm and the National Center for Biotechnology Information non-redundant sequence database. Here the BLASTX hits were further processed by the Metagenome Analyzer program to statistically analyze the abundance of taxa. Results: Microbial community in the rumen is defined by dominance of Bacteroidetes compared to Firmicutes. The ratio of Firmicutes versus Bacteroidetes was 0.36:1. An abundance of Synergistetes was uniquely identified in the goat microbiome may be formed by host genotype. With regard to bacterial lignocellulose degraders, the ratio of lignocellulolytic genes affiliated with Firmicutes compared to the genes linked to Bacteroidetes was 0.11:1, in which the genes encoding putative hemicellulases, carbohydrate esterases, polysaccharide lyases originated from Bacteroidetes were 14 to 20 times higher than from Firmicutes. Firmicutes seem to possess more cellulose hydrolysis capacity showing a Firmicutes/Bacteroidetes ratio of 0.35:1. Analysis of lignocellulolytic potential degraders shows that four species belonged to Bacteroidetes phylum, while two species belonged to Firmicutes phylum harbouring at least 12 different catalytic domains for all lignocellulose pretreatment, cellulose, as well as hemicellulose saccharification. Conclusion: Based on these findings, we speculate that increasing the members of Bacteroidetes to keep a low ratio of Firmicutes versus Bacteroidetes in goat rumen has resulted most likely in an increased lignocellulose digestion.