71 research outputs found

    Influence of biofertilizer produced using drumstick (Moringa oleifera L.) unused parts on the growth performance of two leafy vegetables

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    The non-edible parts of Moringa oleifera, such as stems, branches or leaf petioles, have often been discarded while the leaves are consumed as a vegetable or are used to produce organic fertilizer. This study aimed to determine the optimal conditions for producing Moringa organic fertilizer (MOF) from previously unused parts and to compare these fertilizers with cow manure and bio-organic fertilizer. Seventy kilograms of the unused Moringa parts were blended with fifty kilograms of manure, 0.2 kilogram of Trichoderma-based product and two kilograms of superphosphate. The mixture was incubated at different intervals, including 5, 7 or 9 weeks. Next, the effects of MOF on the growth, yield, ascorbic acid content and Brix of lettuce and mustard spinach were also determined and compared with other organic fertilizers (cow manure and bio-organic fertilizer). Results of the study revealed that 25 tons per ha of MOF were significantly superior to those treated with cow manure and bio-organic fertilizer in the case of vegetable yields. Further, 7 weeks of MOF incubation was found suitable to produce an optimal yield during the various incubation period. These results suggested that the Moringa non-edible parts can make organic fertilizer and enhance growth, yield, and leafy vegetable production

    Mineralogical characteristics of graphite ore from Bao Ha deposit, Lao Cai Province and proposing a wise use

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    Graphite, especially, high quality graphite can be used in many industrial applications including metallurgy, batteries, fuel cells, and refractories. In 2011, Vietnam Ministry of Natural Resources and Environment issued a mineral exploration license to explore Bao Ha graphite deposit, Bao Yen district, Lao Cai Province. The studied samples were taken from 3 drill holes of the Bao Ha largest ore body. Different methods including light microscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), and carbon and sulfur analyzer were performed to identify its lithological and mineralogical characteristics as well as graphite quality, then propose a wise use of the resource. The Bao Ha graphite is characterized as disseminated flake graphite in massive form, which developed in the sillimanite schist and quartz-biotite schist of the Ngoi Chi formation. Graphite flakes occur as distorted clusters of flaky plates/flakes within 50÷500 mm, which is the medium size in comparison with the general grain size of graphite flake. Graphite particle makes up 33÷43% by volume and graphitic content (Cg) makes up 10.0÷11.7 wt.%. Impurities include mainly quartz, biotite, and feldspar (combining of K-feldspar and anorthite, the primary ore) or kaolinite (the weathered ore). This graphite ore should be refined to reach an ore concentration of at least 90% Cg for domestic industries of metallurgy, batteries, thermal materials, and refractories as well as for exports.ReferencesAsbury Carbons, 2015. Natural graphite - Introduction to natural graphite. http://asbury.com/technical-presentations-papers/materials-in-depth/natural-graphite/(Accessed on April 26, 2015). Bergmann J., Friedel P., Kleeberg R., 1998. BGMN - a new fundamental parameters based Rietveld program for laboratory X-ray sources, its use in quantitative analysis and structure investigations. CPD Newsletter 20, 5-8. Bien Xuan Thanh (Editor), 2014. Exploration of graphite deposit in Bao Ha area, Bao Ha community, Bao Yen district, Lao Cai province. Report. Song Da Lao Cai Mining Joint Stock Company. Cameron E., 1960. Graphite: Industrial Minerals and Rocks. Seeley W. Mudd Series, AIME (Chapter 20). European Commission, 2010. Report lists 14 critical mineral raw materials. http://europa.eu/rapid/press-release_MEMO-10-263_en.htm?locale=en. (Accessed on April 26, 2015). Garnier V., Giuliani G., Ohnenstetter D., Fallick A.E., Dubessy J., Banks D., Vinh H.Q., Lhomme T., Maluski H., Pêcher A., Bakhsh K.A., Long P.V., Trinh, P.T., Schwarz D., 2008. Marble-hosted ruby deposits from Central and Southeast Asia: Towards a new genetic model. Ore Geology Reviews, 34, 169-191. Hoang Thai Son (Editor), 1997. Geological and Mineral Resources Map of Vietnam at 1:50,000 scale, sheets Doan Hung - Yen Binh. General Department of Geology and Minerals of Vietnam. Hoang Thai Son, Pham Ngoc Thach, Nguyen The Trung, Chu Hong Phong, Nguyen Ngoc Dung, Pham Xuan Doanh, 2000. Disscussion about metamorphism facies of Song Hong Series. Proceedings. General Department of Geology and Minerals of Vietnam. Industrial Minerals, 2011. Supply Situation Report: Graphite demand soars above precrisis levels. http://www.indmin.com/Print.aspx?ArticleId=2797590 (Accessed on April 04, 2011). Industrial Minerals, 2012. The Natural Graphite Report 2012-Data, analysis and forecast for the next five years. http://www.indmin.com/downloads/reports/graphite2012.pdf. Kleeberg R., Ufer K., Bergmann, 2005. The Quantification of Disordered Clay Minerals by the Rietveld Method - Some Practical Aspects. Presentation at the 42nd Annual Meeting of the Clay Minerals Society, June 11-15, 2005, Burlington/Vermont. Lu X. and Forssberg E., 2001. Flotation selectivity and upgrading of Woxna fine graphite concentrate. Mineral Engineering, 14(l l), 1541-1543. Lu X. and Forssberg E., 2002. Preparation of high-purity and low-sulphur graphite from Woxna fine graphite concentrate by alkali roasting. Minerals Engineering. 15(10), 755-757. Luu Huu Hung (Editor), 2001. Evaluation on graphite of Bao Ha area, Bao Yen, Lao Cai. Report. General Department of Geology and Minerals of Vietnam. Ministry of Industry and Trade, 2016. Circular - amending and supplementing a number of articles of the Minister of Industry and Trade’s circular no. 41/2012/TT-BCT of December 21, 2012, providing the export of minerals (July 05, 2016). https://thuvienphapluat.vn/van-ban/Xuat-nhap-khau/Thong-tu-12-2016-TT-BCT-sua-doi-41-2012-TT-BCT-xuat-khau-khoang-san-316914.aspx Mitchell C.J., 1993. Industrial Minerals Laboratory Manual - Flake Graphite. Technical Report. British Geological Survey. Nguyen Vinh, Phan Truong Thi, 1973. Distribution of contact and dynamic metamorphic rocks in Yen Bai - Nghia Lo area. Journal of Sciences and Techniques of Mining and Geology (ISSN: 1859-1469), 22, 1-13. Hanoi University of Mining and Geology. Northern Graphite Corporation, 2015. Bissett Creek Project. http://northerngraphite.com/bissett-creek-project/ Accessed on April 30, 2015. Persistence Market Research, 2015. Global market study on graphite: Battery segment to witness highest growth by 2020. http://www.persistencemarketresearch.com/market-research/graphite-market.asp. Pham Van Long, Hoang Quang Vinh, Garnier V., Giuliani G., Ohnenstetter D., Lhomme T., Schwarz D., Fallick A., Dubessy J., Phan Trong Trinh, 2004. Gem corundum deposits in Vietnam. Journal of Gemmology, 29(3), 129-147. Pierson H.O., 1993. Handbook of carbon, graphite, diamond and fullerenes - Properties, Processing and Applications. Noyes Publications. Plumbago Co., 2013. What is graphite. http://www.plumbagographite.com/graphite-story/what-is-graphite. (Accessed on April 26, 2015). Rodas M., Luque F.J., Barrenechea J.F., Fernández-Caliani J.C., Miras A., Fernández Rodríguez C., 2000. Graphite occurrences in the Low-Pressure/High-Temperature metamorphic belt of the Sierra de Aracena (Southern Iberian Massif). Mineralogical Magazine, 64, 801-814. Simandl G.J., Paradis S., Valiquette G., Jacob H.L., 1995. Crystalline graphite deposits, classification and economic potential. Proceedings of 28th Forum on the Geology of Industrial Minerals, Marinsburg, West Virginia, May 3-8, 1992, 168-174. Simandl G.J., Paradis S., Akam C., 2015. Graphite deposit types, their origin, and economic significance. In: Simandl G.J. and Neetz M., (Eds.), Symposium on Strategic and Critical Materials Proceedings, November 13-14, 2015, Victoria, British Columbia, British Columbia Ministry of Energy and Mines, British Columbia Geological Survey Paper 2015-3, 163-171. Tran Thi Hien, Vu Tan Co, Chu Van Hoan, Vu Van Ha, Bui Van Ngu, Nguyen Duc Minh, Nguyen Bao Linh, Tran Duc Dung, 2008. Study about mineral processing technology for graphite ore from Nam Thi mine - Lao Cai province. Report. National Institute of Mining - Metallurgy Science and Technology, Vietnam. Tran Van Tri, Vu Khuc (Editors), 2001. Geology and Earth Resources of Vietnam. General Department of Geology and Minerals of Vietnam. Publishing House for Science and Technology, 645p. Tran Xuyen (Editor), 1988. Geological and Mineral Resources Map of Vietnam at 1:200,000 scale, sheets Bac Quang - Ma Quan. Map explanation. General Department of Geology and Minerals of Vietnam. U.S Geological Survey, 2007. 2007 Minerals Yearbook - Graphite. U.S Geological Survey, 10. U.S Geological Survey, 2012. Mineral commodity summaries 2012. U.S Geological Survey, 68-69. U.S Geological Survey, 2017. Mineral commodity summaries 2017. U.S Geological Survey, 74-75. Ufer K., Stanjek H., Roth G., Dohrmann R., Kleeberg R., Kaufhold S., 2008. Quantitative phase analysis of bentonites by the Rietveld method. Clay Mineral 56(2), 272-282. http://dx.doi.org/10.1346/CCMN.2008.0560210. Volkova S.A., Il’icheva O.M., Kuznetsov O.B., 2011. X-ray study of the graphite-bearing rocks from the Pestpaksha ore occurrence and structural features of graphite. Lithology and Mineral Resources, 46(4), 363-368. Vietnam Standards and Quality Institute, 1989. TCVN 4688:1989 Graphite concentrate - Marks and technical requirements.

    Factors Affecting Successful Quality Assurance Implementation in Vietnamese Higher Education: A Qualitative Study

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    Quality assurance and accreditation was officially introduced into the higher education system in Vietnam over ten years ago. It is evident that quality assurance has resulted in positive impacts on university management, teaching, learning and research activities. This paper aims to explore factors that aid the successful implementation of higher education quality assurance and accreditation in Vietnam. Through semi-structured interviews with 32 participants, this study identified a number of factors that contributed to quality assurance processes, including awareness of the importance of quality assurance, better institutional manager leadership, support of university lecturers, staff, and students, and the vital responsibility of internal quality assurance staff. These confirm that internal stakeholders play an important role in undertaking quality assurance programmes and activities

    BIẾN ĐỘNG GIÁ ĐẤT Ở TẠI KHU VỰC TRUNG TÂM VÀ VEN ĐÔ THÀNH PHỐ HUẾ

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    This paper aims to identify the fluctuation of residential land prices in the central and peri-urban areas of Hue City by collecting the state and market prices from 2018 to 2022. Our result indicated that the state land price has adjusted many times but is still low, the price of central areas fluctuated between 1 and 15 million VND/m2, while in the peri-urban areas, it altered between 0.41 and 6.24 million VND/m2. The market’s land price ranged from 9–75 million VND/m2 in central and peri-urban areas from 5 to 55 million VND/m2. There were numerous fluctuations in the period 2018 - 2022 due to the Covid-19 epidemic, increased bank interest rates, and alterations in administrative boundaries. The residential land prices of peri-urban exhibited an upward trend from 2018 to 2021 but declined in 2022 compared to the central area. Peri-urban areas experienced more pronounced fluctuations in prices compared to central areas, with the difference in land prices between the market and state still notably high. In particular, there were substantial differences in the land prices located in the second, third, and fourth positions. Simultaneously, the research has put forward several solutions aimed at determining residential land prices regulated by the state to align more closely with market prices.Bài báo này nhằm xác định  sự biến động giá đất ở tại khu vực trung tâm và ven đô thành phố Huế thông qua việc thu thập dữ liệu về giá đất ở của nhà nước và thị trường trong giai đoạn 2018–2022. Kết quả nghiên cứu cho thấy, giá đất ở nhà nước tại cả hai khu vực đều được điều chỉnh nhiều lần nhưng vẫn còn thấp với khu vực trung tâm từ 1,49–15 triệu đồng/m2 và khu vực ven đô từ 0,41–6,24 triệu đồng/m2. Giá đất ở thị trường dao động từ 9–75 triệu đồng/m2 khu vực trung tâm và khu vực ven đô từ 5–55 triệu đồng/m2. Trong giai đoạn 2018–2022 đã xảy ra nhiều biến động do dịch Covid - 19, gia tăng lãi suất ngân hàng, thay đổi địa giới hành. Giá đất ở khu vực ven đô có xu hướng tăng trong giai đoạn 2018–2021 và giảm vào năm 2022 so với khu vực trung tâm. Tỷ lệ chênh lệch giữa giá đất ở của thị trường và nhà nước còn ở mức cao với chênh lệch cao hơn tại khu vực ven đô, đặc biệt mức chênh lệch cao xuất hiện  tại các vị trí 2, 3 và 4 . Đồng thời, nghiên cứu đã đưa ra được một số giải pháp nhằm xác định giá đất ở do nhà nước quy định tiệm cận giá đất ở thị trường. 

    Liver Involvement Associated with Dengue Infection in Adults in Vietnam

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    Globally, the number of adults hospitalized with dengue has increased markedly in recent years. It has been suggested that hepatic dysfunction is more significant in this group than among children. We describe the spectrum and evolution of disease manifestations among 644 adults with dengue who were prospectively recruited on admission to a major infectious disease hospital in southern Vietnam and compare them with a group of patients with similar illnesses not caused by dengue. Transaminase levels increased in virtually all dengue patients and correlated with other markers of disease severity. However, peak enzyme values usually occurred later than other complications. Clinically severe liver involvement was infrequent and idiosyncratic, but usually resulted in severe bleeding. Chronic co-infection with hepatitis B was associated with modestly but significantly increased levels of alanine aminotransferase, but did not otherwise impact the clinical picture

    ẢNH HƯỞNG CỦA MỘT SỐ YẾU TỐ ĐẾN QUÁ TRÌNH CHẾ TẠO NANO BẠC SỬ DỤNG DỊCH CHIẾT LÁ VỐI LÀM TÁC NHÂN KHỬ

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    In this study, we use the aqueous extract of Robusta plant leaves as a reducing agent and alginate as a surfactant to synthesize silver nanoparticles from silver nitrate (AgNO3). The influence of extraction time and the solid-liquid ratio, the concentration of AgNO3, the volume ratio between silver nitrate solution and the extract of Robusta leaves, and the reaction time on the synthesis were investigated. The optimal conditions are as follows: 15 g of leaves/200 mL, silver nitrate concentration 4 mM, Vextract/VAgNO3 4:100, 1% sodium alginate solution, and reaction time 45 minutes. The obtained solution of silver nanoparticles has a yellow-brown color. The TEM, XRD, and FT-IR measurements of the samples show that the silver nanoparticles have been successfully synthesized. The particles are spherical with an even size and 19.0-26.6 nm in diameter.Trong nghiên cứu này, chúng tôi trình bày phương pháp điều chế dung dịch nano bạc (Ag) từ bạc nitrate (AgNO3) sử dụng dịch chiết lá vối làm tác nhân khử và alginate là chất hoạt động bề mặt. Chúng tôi khảo sát ảnh hưởng của nồng độ AgNO3, tỷ lệ thể tích giữa AgNO3 và dịch chiết lá vối và thời gian phản ứng đến quá trình tạo nano Ag. Điều kiện tối ưu để tổng hợp nano Ag sử dụng dịch chiết lá vối gồm nồng độ AgNO3 4 mM, tỷ lệ thể tích Vdịch chiết /VAgNO3 = 4:100, nồng độ alginate 1%, thời gian phản ứng 45 phút tại nhiệt độ phòng. Dung dịch nano Ag thu được có màu vàng nâu đồng nhất. Kết quả đo TEM, SEM, XRD và FT-IR của các mẫu cho thấy nano Ag đã được tổng hợp thành công; hạt nano có dạng hình cầu, cấu trúc đồng đều với kích thước hạt khoảng 19,0–26,6 nm

    Evaluation of the Luminex xTAG Respiratory Viral Panel FAST v2 assay for detection of multiple respiratory viral pathogens in nasal and throat swabs in Vietnam.

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    BACKGROUND: Acute respiratory infections (ARI) are among the leading causes of hospitalization in children ≤5 years old. Rapid diagnostics of viral pathogens is essential to avoid unnecessary antibiotic treatment, thereby slowing down antibiotic-resistance. We evaluated the diagnostic performance of the Luminex xTAG Respiratory Viral Panel FAST v2 against viral specific PCR as reference assays for ARI in Vietnam. METHODS: Four hundred and forty two nose and throat swabs were collected in viral transport medium, and were tested with Luminex xTAG Respiratory Viral Panel FAST v2. Multiplex RT-PCR and single RT-PCR were used as references.    Results: Overall, viral pathogens were detected in a total count of 270/294 (91.8%, 95% CI 88.1-94.7) by the Luminex among reference assays, whilst 112/6336 (1.8%, 95% CI, 1.4-2.1) of pathogens were detected by the Luminex, but not by reference assays. Frequency of pathogens detected by Luminex and reference assays was 379 and 292, respectively. The diagnostic yield was 66.7% (295/442, 95%CI 62.1-71.1%) for the Luminex assay and 54.1% (239/442, 95% CI, 49.3-58.8%) for reference assays. The Luminex kit had higher yields for all viruses except influenza B virus, respiratory syncytial virus, and human bocavirus. High agreements between both methods [mean (range): 0.91 (0.83-1.00)] were found for 10/15 viral agents. CONCLUSIONS: The Luminex assay is a high throughput multiplex platform for rapid detection of common viral pathogens causing ARI. Although the current high cost may prevent Luminex assays from being widely used, especially in limited resource settings where ARI are felt most, its introduction in clinical diagnostics may help reduce unnecessary use of antibiotic prescription

    Toxoplasma gondii contamination in fresh vegetables destined for human and livestock consumption in Thua Thien Hue, Vietnam

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    Toxoplasmosis caused by Toxoplasma gondii is an important zoonosis that shows severe symptoms in immunocompromised patients. High seroprevalences of toxoplasmosis were found in cats, humans, and pigs in traditional farms in Thua Thien Hue province. The main sources of infections remain unknown, thus making toxoplasmosis neglected and uncontrollable in this region. This study aimed to determine T. gondii contamination in vegetables used for human and livestock consumption and its spatial distribution in Thua Thien Hue rural areas. A cross-sectional study was conducted to investigate T. gondii contamination in vegetables grown in households in three different geographic regions. The pathogen DNA was detected from vegetable samples using a primer pair that is highly specific for the 529-bp repetitive element found in T. gondii genome. In this study, 55 out of 221 (24.9%) vegetable samples were positive for T. gondii using PCR. Factors, including location, presence of fence in the garden, owning cats, and treatment of feed for cats, were not significantly associated with T. gondii contamination in vegetables according to the logistic regression. However, vegetables collected in households that have no fence for vegetable gardens, own cats, and feed cats raw or undercooked foods tend to be more heavily contaminated than others. Furthermore, a wide distribution of infected vegetables was observed in all investigated districts, showing a high infection pressure in these residential areas. This is the first report of vegetables contaminated with T. gondii in Vietnam, which reveals an overlooked health risk for humans and animals

    The Effectiveness of Narrow Band Uvb (Nb-Uvb) In the Treatment of Pityriasis Lichenoides Chronica (PLC) In Vietnam

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    AIM: This prospective clinical study presents the experiences with NB-UVB monotherapy in the treatment of PLC on Vietnamese patients. METHODS: We enrolled at National Hospital of Dermatology and Venereology (NHDV), Vietnam, 29 PLC patients with generalised disease involving at least 60% of the total body surface (based on Nine’s Rule) and/or failed to respond to other modalities of treatment. Patients were treated with NB-UVB followed the guideline of the psoriatic treatment of AAD-2010, three times weekly. RESULTS: A complete response (CR) was seen in 24 out of 29 PLC patients (82.8%) with a mean cumulative dose of 9760.5 mJ/cm2 after a mean treatment period of 4.6 weeks (13.8 ± 7.4 exposures). Mild side effects were observed: 69% erythema minimum, 55.2% irritation related to dry skin. No severe side effects were seen during the study. No relapses occurred in 24 CR patients within a mean period of 3 months after the last treatment. CONCLUSION: NB-UVB therapy is an effective and safe option for the treatment and management of PLC

    The influence of human genetic variation on early transcriptional responses and protective immunity following immunization with Rotarix vaccine in infants in Ho Chi Minh City in Vietnam : a study protocol for an open single-arm interventional trial [awaiting peer review]

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    Background: Rotavirus (RoV) remains the leading cause of acute gastroenteritis in infants and children aged under five years in both high- and low-middle-income countries (LMICs). In LMICs, RoV infections are associated with substantial mortality. Two RoV vaccines (Rotarix and Rotateq) are widely available for use in infants, both of which have been shown to be highly efficacious in Europe and North America. However, for unknown reasons, these RoV vaccines have markedly lower efficacy in LMICs. We hypothesize that poor RoV vaccine efficacy across in certain regions may be associated with genetic heritability or gene expression in the human host. Methods/design: We designed an open-label single-arm interventional trial with the Rotarix RoV vaccine to identify genetic and transcriptomic markers associated with generating a protective immune response against RoV. Overall, 1,000 infants will be recruited prior to Expanded Program on Immunization (EPI) vaccinations at two months of age and vaccinated with oral Rotarix vaccine at two and three months, after which the infants will be followed-up for diarrheal disease until 18 months of age. Blood sampling for genetics, transcriptomics, and immunological analysis will be conducted before each Rotarix vaccination, 2-3 days post-vaccination, and at each follow-up visit (i.e. 6, 12 and 18 months of age). Stool samples will be collected during each diarrheal episode to identify RoV infection. The primary outcome will be Rotarix vaccine failure events (i.e. symptomatic RoV infection despite vaccination), secondary outcomes will be antibody responses and genotypic characterization of the infection virus in Rotarix failure events. Discussion: This study will be the largest and best powered study of its kind to be conducted to date in infants, and will be critical for our understanding of RoV immunity, human genetics in the Vietnam population, and mechanisms determining RoV vaccine-mediated protection. Registration: ClinicalTrials.gov, ID: NCT03587389. Registered on 16 July 2018
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