BISMUTH FILM ELECTRODE FOR MEASUREMENT OF TRACE LEAD BY ADSORPTIVE STRIPPING VOLTAMMETRY WITH CALCEIN BLUE

Joint Research on Environmental Science and Technology for the Eart

Results of magnetotelluric survey for studying geothermal system in the Bang area, Quang Binh province

This paper presents the first results from the application of magnetotelluric method (MT) using the new equipment MTU 2000 (Canada) and analysis software to investigate the structure of geothermal area around the Bang hot water source (Quang Binh province). Results of data analysis by MT 1D and 2D models to a depth of 20 km show low resistivity zone in the southwest of Bang hot water (100°C) and allow for interpreting the structural elements of athehydro- geothermal system. This includes a very low resistivity layer at depth of 2 km suggesting a clay cap (heat resistive shield), a relatively low resistivity zone at depth ≥ 2 km reflecting  fractured rocks containing geothermal fluid and hot steam. A lower resistivity body at depth of 12-14 km located about 1.5 km from the hot water source indicates the existence of a heat source or a hot mass of intrusive magma., commonly thought to be sources of typical hydro- geothermal systems potential for energy exploitation. The obtained results not only provide new information for better understanding geothermal resource in the surveyed area, but also point out the methods and technology needed to improve the effectiveness for assessing potential of geothermal resources elsewhere in Vietnam.ReferencesBản đồ Địa chất và khoáng sản Việt Nam tỷ lệ 1:1.000.000. Cục Địa chất và Khoáng sản Việt Nam xuất bản 2004. Lưu trữ Địa chất. Cumming W., 2009: Geothermal resource conceptual models using surface exploration data. In: proceedings, 34th workshop on geothermal reservoir engineering, Stanford University. Data Processing User guide. Phoenix Geophysic Ltd. 2005, 201p. Di Pippo R., 2012: Geothermal Power plant. Principles, applications, case studies. 3rd edition. Elseverdirect, 579p. Doan Van Tuyen, Tran Anh Vu, Nguyen Thi Kim Thuong, 2014: Geochemical Characteristics of Geothermal Hot Water Sources on the Territory of Vietnam. Proceeding, Thirty-Eighth Workshop on Geothermal Reservoir Engineering Stanford University, Stanford, California, February 24-26, 2014 SGP-TR-202. Duchkov A.D., Nguyen Trong Yem, Dinh Van Toan, and Trinh Viet Bac, 1992: First estimations of heat flow in northern Vietnam. Soviet Geology and Geophysics, Vol. 33, No. 5, pp 92-96. Flynn T., Quy H. H., 1997: Assessment of the geothermal resources of Socialist Republic of Vietnam. Geothermal resources Council Transactions, vol.21, 341-345. IGA report, 2013: Geothermal Exploration best practices: A Guide to resource data collection, analysis, and presentation for Geothermal projects. He Lijuan, 1999: Analysis of heat flow along a transect across the South China Sea. Geothermal Training Programme, Reports 1999, Number 5, 125-140. Hoang Huu Quy, 1998: Overview of the Geothermal potential of Vietnam. Geothermics, Vol.27, n.1, 109-115. Koenig J. et al., 1981: Evaluation of the potential for Geothermal Energy Resources in the SR of Vietnam. Berkeley, CA. Kulinich G.G., Zabolotnikov A.A, Markov Yu., 1989: Cenozoic evalution of the Earth crust and orogeny in South- Eastern Asia (Tiếng Nga). MTU2000: User guide. Phoenix Geophysic Ltd. 2000, 36p. Munoz Gerard, 2014: Exploring for Geothermal Resources with Electromagnetic Methods. Surv Geophys (2014) 35:101-122, Springer, DOI 10.1007/s10712-013-9236-0. Pellerin et al., Johnston M, Hohmann W., 1996: A numerical evaluation of electromagnetic methods in geothermal exploration. Geophysics 61(1996):121-130. Thomas Mathews, et al., 2008: Study on the sozio-economic framework for the use Geothermal energy in Vietnam. Proceedings of the 8th Asian Geothermal Symposium, Hanoi. Trần Huyên, Trương Minh, Nguyễn Tiến Bào, 1999: Về chế độ địa nhiệt ở các bể trầm tích thềm lục địa Việt Nam. Tạp chí Kinh tế Địa chất và Nguyên liệu khoáng. Cục Địa chất và Khoáng sản Việt Nam. Số 18 tháng 2 năm 1999, tr.16-25. Võ Công Nghiệp (chủ biên), 1998: Danh bạ các nguồn nước khoáng và nước nóng Việt Nam. Cục Địa chất và Khoáng sản Việt Nam. Hà Nội, 300tr. Zhdanov M., 2009: Geophysical Electromagnetic Theory and Methods. Methods in Geochemistry and Geophysics, Volume 43. ISSN: 0076-6895 Elsevier, 831pp. WinGLink User guide. Geosystem 200, 182p. www.geosystem.net.

Micronutrient Deficits Are Still Public Health Issues among Women and Young Children in Vietnam

Background: The 2000 Vietnamese National Nutrition Survey showed that the population’s dietary intake had improved since 1987. However, inequalities were found in food consumption between socioeconomic groups. As no national data exist on the prevalence of micronutrient deficiencies, a survey was conducted in 2010 to assess the micronutrient status of randomly selected 1526 women of reproductive age and 586 children aged 6–75 mo. Principal Findings: In women, according to international thresholds, prevalence of zinc deficiency (ZnD, 67.262.6%) and vitamin B12 deficiency (11.761.7%) represented public health problems, whereas prevalence of anemia (11.661.0%) and iron deficiency (ID, 13.761.1%) were considered low, and folate (,3%) and vitamin A (VAD,,2%) deficiencies were considered negligible. However, many women had marginal folate (25.1%) and vitamin A status (13.6%). Moreover, overweight (BMI$23 kg/m 2 for Asian population) or underweight occurred in 20 % of women respectively highlighting the double burden of malnutrition. In children, a similar pattern was observed for ZnD (51.963.5%), anemia (9.161.4%) and ID (12.961.5%) whereas prevalence of marginal vitamin A status was also high (47.362.2%). There was a significant effect of age on anemia and ID prevalence, with the youngest age group (6–17 mo) having the highest risk for anemia, ID, ZnD and marginal vitamin A status as compared to other groups. Moreover, the poorest groups of population had a higher risk for zinc, anemia and ID

Safety and efficacy of fluoxetine on functional outcome after acute stroke (AFFINITY): a randomised, double-blind, placebo-controlled trial

Background Trials of fluoxetine for recovery after stroke report conflicting results. The Assessment oF FluoxetINe In sTroke recoverY (AFFINITY) trial aimed to show if daily oral fluoxetine for 6 months after stroke improves functional outcome in an ethnically diverse population. Methods AFFINITY was a randomised, parallel-group, double-blind, placebo-controlled trial done in 43 hospital stroke units in Australia (n=29), New Zealand (four), and Vietnam (ten). Eligible patients were adults (aged ≥18 years) with a clinical diagnosis of acute stroke in the previous 2–15 days, brain imaging consistent with ischaemic or haemorrhagic stroke, and a persisting neurological deficit that produced a modified Rankin Scale (mRS) score of 1 or more. Patients were randomly assigned 1:1 via a web-based system using a minimisation algorithm to once daily, oral fluoxetine 20 mg capsules or matching placebo for 6 months. Patients, carers, investigators, and outcome assessors were masked to the treatment allocation. The primary outcome was functional status, measured by the mRS, at 6 months. The primary analysis was an ordinal logistic regression of the mRS at 6 months, adjusted for minimisation variables. Primary and safety analyses were done according to the patient's treatment allocation. The trial is registered with the Australian New Zealand Clinical Trials Registry, ACTRN12611000774921. Findings Between Jan 11, 2013, and June 30, 2019, 1280 patients were recruited in Australia (n=532), New Zealand (n=42), and Vietnam (n=706), of whom 642 were randomly assigned to fluoxetine and 638 were randomly assigned to placebo. Mean duration of trial treatment was 167 days (SD 48·1). At 6 months, mRS data were available in 624 (97%) patients in the fluoxetine group and 632 (99%) in the placebo group. The distribution of mRS categories was similar in the fluoxetine and placebo groups (adjusted common odds ratio 0·94, 95% CI 0·76–1·15; p=0·53). Compared with patients in the placebo group, patients in the fluoxetine group had more falls (20 [3%] vs seven [1%]; p=0·018), bone fractures (19 [3%] vs six [1%]; p=0·014), and epileptic seizures (ten [2%] vs two [<1%]; p=0·038) at 6 months. Interpretation Oral fluoxetine 20 mg daily for 6 months after acute stroke did not improve functional outcome and increased the risk of falls, bone fractures, and epileptic seizures. These results do not support the use of fluoxetine to improve functional outcome after stroke

Effects of Green Supply Chain Management Practices on Sustainability Performance: A Systematic Literature Review and Directions for Future Research

In the context that the world is increasingly paying attention to sustainable development, green supply chain management becomes the optimal solution to help balance the three effects of sustainability: economic, environmental, and social. This paper provides a research overview of sustainability performance and green supply chain management practices. Thence, the authors propose a research model on the impact of green supply chain management on the sustainability performance of small and medium enterprises in Vietnam. Keywords:Green Supply Chain Management (GSCM), sustainability performance, Small and Medium Enterprises. DOI: 10.7176/JESD/13-10-01 Publication date:May 31st 202

Simultaneous determination of chloramphenicol and tinidazole by electrochemical analysis using MnO2/electrochemically reduced graphene oxide modified electrode

Manganese (IV) oxide/electrochemically reduced graphene oxide (MnO2/ErGO) composite was synthesized in an oxidation-reduction process followed by electrochemical reduction. The obtained materials were characterized with X-ray diffraction (XRD), electrochemical impedance spectroscopy (EIS), and scanning electron microscopy (SEM) with energy-dispersive X-ray mapping (EDX mapping). The electrochemical reduction of a manganese dioxide/GO film pre-cast on a glassy carbon electrode to rGO was performed by using the chronoamperometric method for preparing the MnO2/ErGO modified electrode. The obtained modified electrode was employed to simultaneously determine chloramphenicol (CAP) and tinidazole (TNZ) with linear sweep adsorptive cathodic stripping voltammetry (LS-AdCSV). The effect of experimental parameters, e.g., potential and time of accumulation, pH of the buffered solutions, and the potential sweep rate on the response, was examined. Under the optimal conditions, the modified electrode shows a wide linear response for the concentration of CAP and TNZ in the range of 0.1–20 μM with a detection limit of 0.58 and 0.33 μM. The practicability of the developed sensor was explored by detecting CAP and TNZ individually or simultaneously in honey, eye drops, and tablet samples with satisfactory results

An overview of northern Vietnam deep crustal structures from integrated geophysical observations

Multiple geophysical datasets from northern Vietnam were examined and reanalyzed to explore detailed structures within the deep crust and their relationship to major tectonic fault systems in this region. Deep seismic data using explosions were collected and examined to crustal structure in northern Vietnam. Based on the determined depths of seismic boundaries, we verified crustal densities by gravity inversion model of Bouguer anomalies. Then, refer to those verified crustal densities; crustal interface boundaries along selected profiles in northern Vietnam were inverted by fitting its gravity anomalies. Integration results reveal significant lateral variations in the depth of the Moho discontinuity. The Moho depth increases from coastal to mountainous areas, and increases more rapidly towards the northwest. The rapid thickening of the crust can be considered as the southeastern extension of the eastern Tibetan along the eastern Himalayan syntaxis. We deduce that these variations are controlled by the main tectonic faults in northern Vietnam. Furthermore, although the Red River fault zone is considered as a boundary between two regional crustal blocks, however, no remarkable differences in crustal density and Moho depth were obtained by our analysis. A comparison of previous magnetotelluric studies and heat-flow observations indicates that the low resistivity of the uppermost mantle beneath the Hanoi basin region is well correlated with the location of a high heat-flow anomaly. The high heat-flow and thin crust determined in this study is suggestive of a recent rifting process of the opening of the South China Sea

Deep Inferior Epigastric Perforator Flap for Immediate Breast Reconstruction following Mastectomy in Breast Cancer Patients: An Initial Experience in Vietnam

Background. Breast reconstruction in breast cancer patients is an optional surgery that improves the quality of life while preserving the efficacy of chemotherapy and radiotherapy. Deep inferior epigastric perforator (DIEP) flap is a new but reliable and safe technique for autologous breast reconstruction. After mastectomy, immediate reconstruction is the preferred method because of its aesthetic result and convenience. This study is aimed at summarizing our experience in DIEP flap for immediate breast reconstruction. Methods. A prospective study was performed on 30 breast cancer patients who underwent intermediate breast reconstruction for DIEP flap after mastectomy from June 2019 to June 2021 in Hanoi Medical University Hospital. Clinicopathology characteristics, tumor stage, treatment, and complications were evaluated. Result. The mean age of patients was 44.9 (range: 29-73 years). 86.7% of patients were in stages I and II. Five patients (16.7%) received neoadjuvant chemotherapy. 20 patients (66.7%) underwent nipple-sparing mastectomy (NSM) procedures. The mean operating time was 341 minutes. The mean time to receive chemotherapy was 34.68 days. The mean number of perforators was 1.30. The overall flap success rate was 90%. Twelve patients (40%) experienced complications. Four patients (13.3%) returned to the operating room due to venous congestions. Two patients (6.67%) had complete flap loss. Other complication: fat necrosis (6.7%), seroma (13.3%), partial flap loss (3.3%), abdominal wound dehiscence (6.7%), pneumonia (3.3%), and pulmonary embolism (6.7%). After one-month postoperation, 88.9% of patients were satisfied with their breasts, and 74.07% were satisfied with the operation. Conclusion. DIEP flap is a new but reliable and safe technique for autologous breast reconstruction. Though patients opting for breast reconstruction still have a low risk of complication and reconstruction failure, this procedure should be used more frequently in appropriate patients to improve their quality of life