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      • KCI등재

        The Activation of Glycerol Dehydrogenase from Escherichia coli by ppGpp

        Huyen Nga Hoang,Thanh Tuyen Tran,Che-Hun Jung 대한화학회 2020 Bulletin of the Korean Chemical Society Vol.41 No.2

        Glycerol dehydrogenase (GldA) from Escherichia coli is a Zn2+-containing alcohol dehydrogenase which catalyzes the NAD+-dependent oxidation of glycerol to dihydroxyacetone. In this study, GldA has been cloned, over-expressed, and isolated by an affinity and an ion-exchange chromatography. GldA shows a strong intrinsic fluorescence at 320?nm, when excited at 280?nm. The fluorescence intensity decreases in the presence of NAD+, NADH, and dihydroxyacetone, the substrate and products for GldA, which allows us to determine the dissociation constants for those molecules as 110.6?±?5.0 ?M, 9,1?±?0.6 ?M, 33.3?±?2.3 mM, respectively. The dissociation constant for NAD+ was similar to the kinetic constant, KM. Guanosine-5?-diphosphate 3?-diphosphate (ppGpp), accumulated in E. coli when starved for amino acids, nutrients, and phosphate, serves as a global regulator in replication, transcription, and translation. In this study, the fluorescence intensity of GldA also decreases in the presence of ppGpp and the dissociation constant for ppGpp is calculated as 108.9?±?8.6 ?M. ppGpp increases GldA activity with the half maximal activation at 33.1?±?3.1 ?M. On the contrary, GTP and GDP inhibit GldA, with the inhibition constants of 16.1?±?1.1 mM and 10.6?±?0.3 mM, respectively. Tris(hydroxymethyl)aminomethane serves as a competitive inhibitor against glycerol. GTP and GDP also bind to GldA with the dissociation constants of 60.0?±?0.8 and 61.0?±?1.3 ?M, respectively. These results suggest that GTP and GDP bind to GldA as strongly as ppGpp but only ppGpp activates GldA. This study shows that ppGpp binds to GldA and activates its activity for the first time. It is also suggested that the strong intrinsic fluorescence of enzymes and their changes in the presence of various ligands can be utilized to measure the binding affinities for those ligands. The method described here is especially effective for bindings with the relatively lower affinities.

      • Access to Anti-smoking Information among School Children and its Potential Impact on Preventing Smoking Initiation: Results from the Global Youth Tobacco Use Survey (GYTS) 2014 in Viet Nam

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

        Scientific evidence on all aspects of smoking amongst youth is very important for designing appropriate interventions to reduce smoking among this vulnerable population. This paper describes current access to anti-smoking information among school children aged 13 to 15 years in Vietnam in 2014 and examines its potential impact on preventing smoking initiation. The data used in this paper were obtained from the 2014 Global Youth Tobacco Survey (GYTS) in Vietnam. Students were asked questions about their level of awareness of anti-smoking information from various sources in the past 30 days and about lessons in school regarding the dangers of tobacco use during the last 12 months. Those who have never smoked were asked "whether or not they thought about avoiding cigarettes because of health warnings on cigarette packages" and answers were analyzed in combination with data on access to anti-smoking information from other sources. The prevalence of exposure to antismoking campaigns was high among school children in Viet Nam: 55.3% of current smokers reported thoughts of smoking cessation because of health warnings on cigarette packages; 60.5% of never smokers avoided initiating smoking because of the same health warnings. The potential impact of graphic health warnings to prevent school-aged children from smoking initiation would be stronger if there was concurrent access to anti-smoking programs on the dangers of tobacco use in schools. However, school education for tobacco prevention and control has not been as strong as expected. A more comprehensive school curriculum on tobacco prevention and control is recommended to reinforce antismoking messages among school children.

      • Methodology for the Global Youth Tobacco Use Survey (GYST), Vietnam, 2014

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

        Viet Nam is a country with the highest rate of adult male smokers in the world. In 2010, the percentage of adult male smokers was 47.4%. Each year in Viet Nam, there are 40,000 lives lost from tobacco-related diseases. The Global Tobacco Youth Survey is an international standardized survey that has been conducted in more than 140 countries. To provide evidence for tobacco control, Viet Nam already conducted two rounds of GYTS in 2003 and 2007. The GYTS in 2014 is the survey's third iteration. This paper aims to document key methodological details and socio-demographic characteristics of the respondents included in the 2014 GYTS in Viet Nam. This survey followed international protocol and was conducted in 13 provinces representative of 6 geographical regions. A total of 3,430 school children, aged 13 to 15 years used a standardized answer sheet to answer 76 questions about seven tobacco-related topics, including prevalence of tobacco use, environmental tobacco smoke, access and availability, media and advertisement, cessation, knowledge and attitudes, tobacco-related school curriculum. This GYTS provides valid and reliable data for monitoring tobacco use among youth in Vietnam and is recommended to be regularly repeated.

      • Cigarette Smoking among Adolescents aged 13-15 in Viet Nam and Correlates of Current Cigarette Smoking: Results from GYTS 2014 Data

        Le, Thi Huong,Nga, Thi Thu Vu,Nguyen, Ngoc Dung,Le, Thi Thanh Xuan,Kim, Bao Giang,Phan, Thi Hai,Doan, Thu Huyen,Luong, Ngoc Khue,Nguyen, Tuan Lam,Hoang, Van Minh,Pham, Thi Quynh Nga Asian Pacific Journal of Cancer Prevention 2016 Asian Pacific journal of cancer prevention Vol.17 No.no.sup1

        The aim of this paper is to report the rate of current and ever cigarette smoking and explore correlates of current cigarette smoking among adolescents aged 13-15 in Viet Nam. This analysis was derived from GYTS survey, which comprised of 3,430 adolescents aged 13-15, conducted in 2014 in 13 cities and provinces of Viet Nam. We calculated the weighted rates of current and ever cigarette smoking and reported patterns of smoking behavior. We also performed logistic regression to explore correlates of current cigarette smoking behavior. The weighted rate of ever cigarette smoking was 9.5% (95% confidence interval (CI): 8.5 %-10.5%), in which the weighted rate among males (15.4%; 95% CI: 13.6%-17.0%) was higher than that among females (4.2%; 95% CI: 3.3%-5.1%). The weighted rate of current cigarette smoking was relatively low at 2.5% (95%CI: 2.0%-3.0%) with higher weighted rate among males (4.9%; 95% CI: 3.8%-5.9%) compared to the corresponding figure among females (0.2%; 95% CI: 0.0 %-0.5%). Current cigarette smoking was significantly higher among males than females, in students aged 15 versus 13 years old, and in students who had several or all close friends smoking and students with daily observation of smoking at school. For greater smoking reduction outcomes, we recommend that tobacco interventions for adolescents should consider targeting more male students at older ages, establish stricter adherence to school-based banning of cigarette smoking, engage both smoking and nonsmoking adolescents and empower adolescents to resist peer smoking influence as well as changing their norms or beliefs towards smoking benefits.

      • SCISCIESCOPUS

        Uptake of arsenic and heavy metals by native plants growing near Nui Phao multi-metal mine, northern Vietnam

        Ha, Nguyen Thi Hoang,Ha, Nguyen Thi,Nga, Tran Thi Huyen,Minh, Nguyen Ngoc,Anh, Bui Thi Kim,Hang, Nguyen Thi An,Duc, Nguyen Anh,Nhuan, Mai Trong,Kim, Kyoung-Woong Elsevier 2019 Applied geochemistry Vol.108 No.-

        <P><B>Abstract</B></P> <P>Phytoremediation is a plant-based, environment-friendly, and cost-effective technology that can be potentially used to remediate contaminated media. This study was conducted to evaluate the phytoextraction and phytostabilization potential, two common techniques of phytoremediation, of 21 plant species growing naturally at the largest tungsten (W) mine in Vietnam—the second largest production of W in the world. The average concentrations in different soil fractions were in the following order: residue > organically complexed, Fe- and Mn oxide-bound > carbonate bound > exchangeable. The total concentrations of arsenic (As), cadmium (Cd), copper (Cu), and zinc (Zn) in the soil varied by 34–3390, 4.87–81.6, 14.3–2080, and 21.9–370 mg/kg, respectively. The concentrations of As, Cd, Cu, and Zn in the shoots ranged 0.71–2400, 0.05–5.55, 4.81–249, and 13.3–380 mg/kg-DW, respectively. The concentrations of As and Cd in all soil samples and Cu in 70% of soil samples collected around the mine fluctuated within 2–227, 3–54, and up to 21-folds higher than the maximum allowable limit for agricultural soils in Vietnam (QCVN 03-MT:2015/BTNMT). The results indicated that hyperaccumulation levels (mg/kg-DW) were obtained for only As in <I>Pityrogramma calomelanos</I> (2400) and <I>Pteris vittata</I> L. (1860). Based on the recorded hyperaccumulation levels, translocation and accumulation factors, biomass, and fast growth of these plants, <I>P. calomelanos</I> and <I>P. vittata</I> were considered to be promising native plants for the phytoextraction of As contaminated soils. <I>Bidens pilosa</I> L. also has great potential for phytostabilization of mining soils contaminated with As and heavy metals.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Soils near multi-metal (W–F–Cu–Au–Bi) mine were contaminated with As, Cd, Cu. </LI> <LI> Arsenic in shoots were in order of Fern > Monocotyledonae > Dicotyledonae. </LI> <LI> <I>Pityrogramma calomelanos</I> and <I>Pteris vittata</I> L. suggested for phytoextraction of As. </LI> <LI> <I>Bidens pilosa</I> L. suggested for the phytostabilization of mining contaminated soils. </LI> </UL> </P>

      • 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).

      • Tobacco Access and Availability for Vietnamese School Children (aged 13-15): Results from the Global Youth Tobacco Use Survey (GYTS) 2014 in Viet Nam

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

        Efforts to reduce tobacco use among school children need to be based on understanding of access to cigarettes by these subjects because previous studies indicated that enforcement of laws for controlling tobacco sales seems to not affect teen/school children because they can obtain cigarettes from different sources. This paper aims to describe access to and availability of cigarettes among school students (aged 13-15 years old) according to the data from GYTS Vietnam 2014. In GYTS, a national school-based survey of students of grades 8-10, our findings showed that about 15% school children are current smokers who smoke at home, and that they could easily buy cigarettes from stores (63.2%), or someone else (27.8%), or street vendors (9%). Notably, over 85% of school children answered that they were not refused because of their age. This high percentage was nearly the same in the North (85.7%), the Centre (92.5%), and the South (89.7%) of Viet Nam. These findings show that it is quite easy for school children to obtain cigarettes and this is a crucial challenge for policy makers aiming to reduce tobacco use among youth in general and school-age students in particular.

      • Knowledge and Attitude Towards Tobacco Smoking among 13-15 Year-Old School Children in Viet Nam - Findings from GYTS 2014

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

        Studies have shown that smoking is a learnt behavior, often initiated during adolescence. This paper aims to describe tobacco-related knowledge, attitude and associations among school adolescents aged 13-15 with exposure to anti-smoking information. Using data from the Global Youth Tobacco Survey (GYTS) in Viet Nam, 2014, knowledge was measured through 4 questions about tobacco use, and attitude was assessed through 3 questions on personal, social and environmental aspects. Students giving most anti-tobacco responses to all questions were considered as having correct knowledge or appropriate attitude or both. Access to anti-smoking information was determined by exposure to any media messages on tobacco control during the past 30 days and teaching in school about the danger of tobacco use during the past 12 months. A substantial percentage of students thought that being near others who smoke might be harmful to them and smoking is harmful to health (89.4% and 89.6% respectively). However, only 46.4% reported that it is definitely difficult to quit smoking and 66.9% thought that smoking for only 1 or 2 years, once stopped, is harmful to health. Slightly more than half of the respondents reported appropriate attitude that young smokers have fewer friends than others and smoking makes them less attractive and less comfortable at social events. Noticing anti-smoking messages in the media together with having lessons in school about the dangers of tobacco substantially increased the likelihood of having correct knowledge, appropriate attitude and both. Despite relatively high awareness about smoking harms, effective educational communication is still highly needed to improve the level of comprehensive knowledge and an appropriate attitude regarding tobacco use.

      • Exposure to Tobacco Advertising and Promotion among School Children Aged 13-15 in Vietnam - an Overview from GYTS 2014

        Tran, Khanh Long,Phung, Xuan Son,Kim, Bao Giang,Phan, Thi Hai,Doan, Thi Thu Huyen,Luong, Ngoc Khue,Pham, Thi Quynh Nga,Nguyen, Tuan Lam,Hoang, Van Minh,Le, Thi Thanh Huong Asian Pacific Journal of Cancer Prevention 2016 Asian Pacific journal of cancer prevention Vol.17 No.no.sup1

        Evidence shows that tobacco advertising and promotion activities may increase tobacco consumption and usage, especially in youth. Despite the regulation on prohibiting advertisement of any tobacco product, tobacco advertisement and promotion activities are still common in Vietnam. This article presents current exposure to tobacco advertising and promotion (TAP) among school children aged 13 to 15 years in Vietnam in 2014 and potential influencing factors. Data from the Global Youth Tobacco Survey 2014 in Vietnam covering 3,430 school aged children were used. Both descriptive and analytical statistics were carried out with Stata 13 statistical software. Binary logistic regression was applied to explain the exposure to TAP among youth and examine relationships with individual factors. A significance level of p<0.05 and sampling weights were used in all of the computations. In the past 30 days, 48.6% of the students experienced exposure to at least 1 type of tobacco advertising or promotion. Wearing or otherwise using products related to tobacco was the most exposure TAP type reported by students (22.3%). The internet (22.1), points of sales (19.2) and social events (11.5) were three places that students aged 13-15 frequently were exposed to TAP. Binary logistic results showed that gender (female vs male) (OR = 0.61, 95%CI: 0.52 - 0.71), susceptibility to smoking (OR = 2.12, 95%CI: 1.53 - 2.92), closest friends' smoked (OR = 1.43, 95%CI: 1.2 - 1.7) and parents smoking status (OR = 2.83, 95%CI: 1.6 - 5.01) were significantly associated with TAP exposure among school-aged children. The research findings should contribute to effective implementation of measures for preventing and controlling tobacco use among students aged 13-15 in Viet Nam.

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