Effect of Saline Concentrations on Biological Nitrification in Batch Reactor

Young Joon Lee, Nguyen Viet Hoang, Nguyen Hong Khanh, Pham Tuan Linh, Gi Youn Kim 조선대학교 기초과학연구원 2011 조선자연과학논문집 Vol.4 No.2

Pham Tuan Linh2 and Gi Youn Kim This study was carried out on 4 batch reactors to determine the specific ammonium oxidizing rate (SAOR), specific nitrate forming rate (SNFR) and inhibitory degree of nitrifying activities with saline concentrations. Under salt free condition ammonia was consumed during the reaction period within 200 min. When the salt level increased to 10, 20 and 30 g NaClL-1 in reactor, ammonia depletion took 250, 300 and above 350 min, respectively. During concentration above 10 g NaClL-1, there was nitrite accumulation. Also, at 30 g NaClL-1 ammonia did not depleted and NO2 --N accumulated until the final reaction. Nitrate formation rates decreased with increasing salt concentration. SAOR and SNFR showed a decreasing trend as salinity concentrations were increased. The SAOR was reduced from 0.2 to 0.08 mg NH4+-N g-1VSS day-1 as the salt concentration increased from 0 to 30 g NaCLL-1. Similarly, the SNFR decreased from 0.26 kg NO3--N kg-1VSS day-1 at saline free to 0.1 kg NO3--N kg-1VSS day-1 at saline 30 g L-1. A severe inhibition of nitrifiers activity was observed at increased salt concentrations. The inhibition ratio of specific ammonium oxidation rates were 17, 47 and 60% on the reactor of 10, 20 and 30 g NaClL-1 added, respectively. The inhibition ratio of specific nitrate forming rates also were inhibited 30, 53 and 62% on the reactor of 10, 20 and 30 g NaClL-1 added, respectively. As the salinity concentrations increased from 0 to 30 mg NaClL-1, the average MLSS concentration increased from 1,245 to 1,735 mgL-1. The SS concentration of supernatant in reactor which settled about 30 minutes was not severely difference between concentration of salt free reactor and one of those high salt contained reactors

Development of a Strong Anaerobic Reporter System Based Halotag Protein for Screening Strong Novel Promoters in Hexanoic Acid-producing Clostridium sp. JS66

Linh NGUYEN KHANH,Ki-Yeon KIM,Youngsoon UM 한국생물공학회 2021 한국생물공학회 학술대회 Vol.2021 No.4

Anaplasma marginale and A. platys Characterized from Dairy and Indigenous Cattle and Dogs in Northern Vietnam

Nguyen Thi Hong Chien,Thi Lan Nguyen,Khanh Linh Bui,Tho Van Nguyen,Thanh Hoa Le 대한기생충학ㆍ열대의학회 2019 The Korean Journal of Parasitology Vol.57 No.1

Anaplasma marginale and A. platys were detected and characterized (16S rDNA sequence analysis) from dairy and indigenous cattle, and the latter in domestic dogs in Vietnam. A phylogenetic tree was inferred from 26 representative strains/species of Anaplasma spp. including 10 new sequences from Vietnam. Seven of our Vietnamese sequences fell into the clade of A. marginale and 3 into A. platys, with strong nodal support of 99 and 90%, respectively. Low genetic distances (0.2-0.4%) within each species supported the identification. Anaplasma platys is able to infect humans. Our discovery of this species in cattle and domestic dogs raises considerable concern about zoonotic transmission in Viet- nam. Further systematic investigations are needed to gain data for Anaplasma spp. and members of Anaplasmataceae in animal hosts, vectors and humans across Vietnam.

X-ray absorption spectroscopies of Mg-Al-Ni hydrotalcite like compound for explaining the generation of surface acid sites

Hong Khanh Dieu Nguyen,Toan Dang Nguyen,Dung Ngoc Hoang,Duc Sy Dao,Thao Tien Nguyen,Limphirat Wanwisa,Lan Linh Hoang 한국화학공학회 2017 Korean Journal of Chemical Engineering Vol.34 No.2

Hydrotalcite-like compound containing metal cations such as Mg2+, Al3+ and Ni2+ was characterized using Ni K-edge EXAFS and in situ Ni K-edge XANES techniques for clarifying its bonding environment around Ni2+ sites and structure changes during calcination from room temperature to 550 oC, respectively. At the fixed molar ratio of Mg/Ni/Al of 2/1/1, the results obtained from EXAFS analysis showed a slight blue shift before and after the calcination at 550 oC and a reduction in white line peak; the best fits of the two samples revealed tiny change in coordination number about 7 for Ni-O path but considerable difference for Ni-Mg(Al) path from about 4.5 to 9.5, confirming a modification from brucite like to mixed oxide structure. On the other hand, bond distances of the Ni-O and Ni-Mg paths nearly fixed at about 2.06 Å to 3.0 Å reflected stability of the cationic bond order on each plane, but partial collapse and decomposition of the interlayer formed by water molecules and anion CO3 2− after the calcination. Linear combination fit extracted from the in situ Ni K-edge XANES also confirmed the changes along with the calcination such as slow and fast decreases of brucite fraction at 150 oC and 330 oC, respectively, in corresponding to the mixed oxide fraction increases. The achieved bonding structures were also applied to explain acid-base occurrence of the hydrotalcite-like material, especially the acid sites generated by different static charges along with the bonds. The explanation was illustrated by NH3-TPD method.

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.

The Impact of Extrinsic Work Factors on Job Satisfaction and Organizational Commitment at Higher Education Institutions in Vietnam

Phuong Ngoc Duy NGUYEN,Linh Le Khanh NGUYEN,Dong Nguyen Thanh LE 한국유통과학회 2021 The Journal of Asian Finance, Economics and Busine Vol.8 No.8

The purpose of this study is to explore the link between job satisfaction and organizational commitment at higher education institutions (HEIs) in emerging countries such as Vietnam and to determine extrinsic work factors that influence job satisfaction. Higher education is critical for socio-economic growth and the overall development of each country. Hence, an understanding of what motivates employees’ actions and attitudes should be obtained before determining the extent of employee satisfaction. The conceptual model was developed by incorporating job satisfaction-related variables, their relationships, and the impact of job satisfaction on organizational commitment. An empirical study was conducted on a study sample of public and private universities, with 316 academics and non-academic employees surveyed. The current study employed the partial least squares structural equation modeling to test the proposed hypotheses. The results reveal a positive and significant relationship between job satisfaction and organizational commitment. The findings confirm that extrinsic work factors (job itself, supervision, working conditions, payment, and reward and recognition) have a positive and significant relationship with job satisfaction. Furthermore, the study indicates that employees at HEIs who have a high level of ability utilization and supervisor support are more likely to be satisfied with their jobs.

Vingroup: The Rising Dragon That Put Vietnam on the Global Map

Giap Vu Nam Duong,Hoang Khanh Linh,정경화,Nguyen Khanh Linh,Nguyen Phuong Hoa,Phan Hai Dang,Thai Thi Phuong Nga Academy of Asian Business (AAB) 2022 Academy of Asian Business Review Vol.8 No.1

Vingroup JSC (formerly Technocom) was founded in Ukraine in 1993 as an instant noodle factory. Since then, the Group has expanded into many other industries, placing tourism and hospitality as their first stepping-stone, then venturing into retail, real estate, education, and recently shifting towards a promising industrial and technology industry. Vingroup has now become the largest conglomerate in Vietnam in terms of market capitalization (VnExpress International, 2019). Having established a solid foundation in the Vietnamese market, Vingroup is eyeing the new promising yet challenging international market, with its competitive advantage in industrials and technology. Standing at a crucial juncture in its ascent, the conglomerate must implement a comprehensive and long-term strategy to reach its next milestone. In 2016, Vingroup primarily focused on four main business segments, encompassing property, hospitality - entertainment, consumer retail, and social infrastructure services. Over the course of two decades, Vinpearl and Vincom have grown into the market-leading hospitality and shopping malls brand in Vietnam. The brands’ establishment coincided with the flourishing economy of the country in the early 2000s, therefore, quickly achieved market dominance. Having such favorable conditions, the Group continued its expansion and investment in other backboned industries, which has reaped correspondingly fruitful results. The key success factors of Vingroup lies in an entrepreneurial mindset, speed, perfectionism and discipline, and last but not least, the national spirit. These traits have allowed the Group to unleash its potential capabilities and go beyond all boundaries. Both small-and-medium-sized companies and big firms can take Vingroup as a lesson for their strategy and corporate culture so that they can lead successful and sustainable growth in today’s competitive market.

Trends in Second-Hand Tobacco Smoke Exposure Levels at Home among Viet Nam School Children Aged 13-15 and Associated Factors

Nguyen, Tuan Lam,Pham, Thi Quynh Nga,Hoang, Van Minh,Kim, Bao Giang,Phan, Thi Hai,Doan, Thu Huyen,Nguyen, Thuy Linh,Duong, Khanh Van,Luong, Ngoc Khue Asian Pacific Journal of Cancer Prevention 2016 Asian Pacific journal of cancer prevention Vol.17 No.no.sup1

Second-hand tobacco smoke (SHS) exposure at home, especially among children, is a serious issue in Viet Nam. During the past decade, much effort has been taken for tobacco control in the country, including various prgorammes aiming to reduce SHS exposure among adults and children. This article analysed trends and factors associated with SHS exposure at home among school children aged 13-15 in Viet Nam, using the Global Youth Tobacco Surveys conducted in 2007 and 2014. Descriptive and inferential statistical methods with logistic regression were applied. Overall, there was a significant reduction in the level of exposure, from 58.5% (95%CI: 57.6-59.3) in 2007 to 47.1% (95%CI: 45.4-48.8) in 2014. Of the associated factors, having one or both parents smoking was significantly associated with the highest odds of SHS exposure at home (OR=5.0; 95%CI: 4.2-6.1). Conversely, having a mother with a college or higher education level was found to be a protective factor (OR=0.5; 95%CI: 0.3-0.8).

Understanding the COVID-19 Infodemic: Analyzing User-Generated Online Information During a COVID-19 Outbreak in Vietnam

Ha-Linh Quach,Thai Quang Pham,Ngoc-Anh Hoang,Dinh Cong Phung,Viet-Cuong Nguyen,Son Hong Le,Thanh Cong Le,Dang Hai Le,Anh Duc Dang,Duong Nhu Tran,Nghia Duy Ngu,Florian Vogt,Cong-Khanh Nguyen 대한의료정보학회 2022 Healthcare Informatics Research Vol.28 No.4

Objectives: Online misinformation has reached unprecedented levels during the coronavirus disease 2019 (COVID-19) pandemic. This study analyzed the magnitude and sentiment dynamics of misinformation and unverified information about public health interventions during a COVID-19 outbreak in Da Nang, Vietnam, between July and September 2020. Methods: We analyzed user-generated online information about five public health interventions during the Da Nang outbreak. We compared the volume, source, sentiment polarity, and engagements of online posts before, during, and after the outbreak using negative binomial and logistic regression, and assessed the content validity of the 500 most influential posts. Results: Most of the 54,528 online posts included were generated during the outbreak (n = 46,035; 84.42%) and by online newspapers (n = 32,034; 58.75%). Among the 500 most influential posts, 316 (63.20%) contained genuine information, 10 (2.00%) contained misinformation, 152 (30.40%) were non-factual opinions, and 22 (4.40%) contained unverifiable information. All misinformation posts were made during the outbreak, mostly on social media, and were predominantly negative. Higher levels of engagement were observed for information that was unverifiable (incidence relative risk [IRR] = 2.83; 95% confidence interval [CI], 1.33–0.62), posted during the outbreak (before: IRR = 0.15; 95% CI, 0.07–0.35; after: IRR = 0.46; 95% CI, 0.34-0.63), and with negative sentiment (IRR = 1.84; 95% CI, 1.23–2.75). Negatively toned posts were more likely to be misinformation (odds ratio [OR] = 9.59; 95% CI, 1.20–76.70) or unverified (OR = 5.03; 95% CI, 1.66–15.24). Conclusions: Misinformation and unverified information during the outbreak showed clustering, with social media being particularly affected. This indepth assessment demonstrates the value of analyzing online “infodemics” to inform public health responses.

Orodispersible film incorporating nanoparticulate loratadine for an enhanced oral bioavailability

Van Nguyen Khanh,Dang Thu Kim,Vu Linh Thi Dieu,Ha Nhan Thi,Truong Hieu Duy,Tran Tuan Hiep 한국약제학회 2023 Journal of Pharmaceutical Investigation Vol.53 No.3

Purpose Loratadine (LOR), a commonly prescribed antihistamine, has low water solubility but high permeability. In this study, an orodispersible film incorporating the nanoparticulate loratadine was prepared to enhance the oral bioavailability of a poorly water-soluble drug. Methods Nanoparticulate loratadine was formulated using the antisolvent precipitation method and optimized by a singlefactor design based on the particle size and polydispersity index. The optimal formulation was spray-dried and characterized by powder X-ray diffraction and differential scanning calorimetry. Nanoparticulate loratadine was loaded into an orodispersible film using a solvent casting method. Results In the dissolution tests, the nanoparticulate loratadine-loaded orodispersible film exhibited a 6.5-fold higher dissolution rate than the pure loratadine-loaded film and a similar dissolution rate compared to the commercialized orodispersible tablet, Loratadine SPM. In pharmacokinetic studies conducted on rats, the maximum concentration (Cmax) and area under the curve of the plasma concentration–time profile from 0 to 24 h (AUC 0-24 h) of the nanoparticulate loratadine-loaded orodispersible film significantly increased 1.8-fold and 5.8-fold, respectively. The elimination half-life (t1//2) increased 5.1-fold compared to the loratadine-loaded counterpart. Conclusion These results suggest the potential of orodispersible films to improve the oral bioavailability of poorly watersoluble drugs and promote compliance in pediatric and geriatric patients.