Abstract: Đinh lăng (Polyscias fruticosa (L.) Harms) thuộc họ Araliaceae, được trồng rộng rãi khắp Việt Nam và thường được dùng trong một số bài thuốc dân gian nhằm tăng cường sức khỏe cho con người. Thành phần dược liệu chính trong cây đinh lăng là các hợp chất saponin triterpenoid. Mặc dù đã có một số nghiên cứu tách chiết saponin từ lá, rễ cây đinh lăng và đánh giá tác dụng sinh học, tuy nhiên hiệu suất tách chiết phụ thuộc nhiều vào phương pháp và nguồn vật liệu. Trong nghiên cứu này, chúng tôi tiến hành khảo sát một số yếu tố như phương pháp chiết, nồng độ, tỉ lệ dung môi, thời gian và nhiệt độ ảnh hưởng đến hiệu quả tách chiết saponin tổng số từ lá cây đinh lăng thu thập tại tỉnh Thái Nguyên và đánh giá khả năng chống oxy hoá trong dịch chiết thu được. Kết quả cho thấy, điều kiện tách chiết tối ưu là sử dụng dung môi methanol, tỉ lệ nguyên liệu/dung môi là 1:12, tách chiết trong vòng 4 giờ tại nhiệt độ 70℃ bằng phương pháp khuấy trộn gia nhiệt. Dịch chiết lá được xác định bằng phương pháp quang phổ, hàm lượng saponin là 8,12 ± 0,59 mg/ml có khả năng kháng oxy hóa cao, giá trị IC50 của dịch chiết saponin đạt 17,14 μg/ml.

Abstract: The purpose

Abstract: To investigate the feasibility of establishing hospital-based antimicrobial stewardship (AMS) programmes comprising action-planning, educational interventions and data feedback in two provincial-level hospitals in Viet Nam. Design and setting This was an implementation research using participatory action process and existing resources from the Duke Antimicrobial Stewardship Outreach Network with local adjustments. A national stakeholder meeting and Strengths-Weaknesses-Opportunities-Threats (SWOT) analysis were conducted to identify gaps and potential interventions. Participants Hospital AMS staff implemented activities throughout the study phases. Routinely collected patient data were analysed to support planning, implementation and evaluation. Interventions Hospitals were considered as a complex adaptive system and leveraged their unique characteristics and interconnections to develop 1-year plans containing core interventions (data use, educational training, prospective audit with feedback (PAF) and evaluations). Outcome measures We assessed feasibility using outputs from stakeholder meeting, SWOT analysis, baseline data, planning process and implementation. Results The stakeholder meeting identified three gaps for AMS at national level: supportive policies, AMS training and core competencies and collaboration. At the hospitals, AMS programmes took 1 year for planning due to lack of hospital-specific procedures and relevant staff competencies. Baseline data (January–December 2019) showed variations in antibiotic consumption: 951 days of therapy (DOT) per 1000 days present in the control and 496 in the intervention wards in hospital 1, and 737 and 714 in hospital 2, respectively. During 1-year implementation, clinical pharmacists audited 1890 antibiotic prescriptions in hospital 1 (June 2020–May 2021) and 1628 in hospital 2 (July 2020–July 2021), and will continue PAF in their daily work. Conclusion Our data confirmed the need to contextualise AMS programmes in low-income and middle-income countries (LMICs) and demonstrated the usefulness of implementation research design in assessing programme feasibility. Developing staff competencies, using local data to stimulate actions and integrating programme activities in routine hospital work are key to success in LMICs.

Abstract: This paper presents some results of rainfall forecast in the monsoon onset period in South Vietnam, with the use of ensemble Kalman filter to assimilate observation data into the initial field of the model. The study of rainfall forecasts are experimented at the time of Southern monsoon outbreaks for 3 years (2005, 2008 and 2009), corresponding to 18 cases. In each case, there are five trials, including satellite wind data assimilation, upper-air sounding data assimilation, mixed data (satellite wind+upper-air sounding data) assimilation and two controlled trials (one single predictive test and one multi-physical ensemble prediction), which is equivalent to 85 forecasts for one trial. Based on the statistical evaluation of 36 samples (18 meteorological stations and 18 trials), the results show that Kalman filter assimilates satellite wind data to forecast well rainfall at 48 hours and 72 hours ranges. With 24 hour forecasting period, upper-air sounding data assimilation and mixed data assimilation experiments predicted better rainfall than non-assimilation tests. The results of the assessment based on the phase prediction indicators also show that the ensemble Kalman filter assimilating satellite wind data and mixed data sets improve the rain forecasting capability of the model at 48 hours and 72 hour ranges, while the upper-air sounding data assimilation test produces satisfactory results at the 72 hour forecast range, and the multi-physical ensemble test predicted good rainfall at 24 hour and 48 hour forecasts. The results of this research initially lead to a new research approach, Kalman Filter Application that assimilates the existing observation data into input data of the model that can improve the quality of rainfall forecast in Southern Vietnam and overall country in general.References Bui Minh Tuan, Nguyen Minh Truong, 2013. 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Abstract: Nghiên cứu được thực hiện nhằm mục đích sử dụng mùn cưa gỗ keo lá tràm (Acacia auriculiformis A. Cunn) để trồng nấm Vân chi (Trametes versicolor (L.) Lioud (1920)) từ nguồn nguyên liệu có sẵn tại A Lưới và so sánh giữa 2 địa điểm trồng là A Lưới và thành phố Huế. Thí nghiệm được bố trí gồm 4 công thức và tại 2 địa điểm A Lưới và thành phố Huế, trên hai loại mùn cưa gỗ cao su và mùn cưa gỗ keo lá tràm. Kết quả cho thấy thời gian sinh trưởng, phát triển trên mùn cưa gỗ keo lá tràm rút ngắn hơn so với trên nguyên liệu mùn cưa gỗ cao su khoảng 3 - 4 ngày. Trồng tại A Lưới, nấm vân chi cho kích thước về chiều dài và đường kính quả thể lớn hơn lần lượt là 1,01 - 1,06 cm, và 0,93 - 1,51 cm so với trồng tại thành phố Huế nên năng suất cao hơn từ 2,46 - 3,47 gam/kg nguyên và hiệu quả kinh tế cao hơn, dao động từ 2.776.000 - 3.968.000 đồng. Hàm lượng Pb và Cd trong mùn cưa gỗ keo đạt lần lượt là 41,21 mg/kg và 1,42 mg/kg, hàm lượng Pb trong quả thể nấm vân chi dao động từ 0,010 - 0,013 mg/kg và hàm lượng Cd dao động từ 0,040 - 0,052 mg/kg. Như vậy, nấm vân chi trồng tại A Lưới sinh trưởng phát triển và cho năng suất cao hơn so với trồng tại thành phố Huế và trồng trên nguyên liệu mùn cưa gỗ keo lá tràm cũng cho kết quả về sinh trường và năng suất tương tự với mùn cưa gỗ cao su. Kết quả phân tích hàm lượng kim loại nặng (Pb và Cd) trong nguyên liệu mùn cưa gỗ cao su và mùn cưa gỗ keo lá tràm cũng như trong quả thể nấm vân chi đều nằm trong ngưỡng an toàn cho phép.

Abstract: The Covid-19 pandemic has impacted foreign language education in general and assessment practices in particular. Many changes have been implemented regarding the mode of language testing and assessment when conventional face-to-face examinations cannot be applied. One radical change is the emergence and acceptance of online at-home assessments. The University of Languages and International Studies, Vietnam National University (VNU-ULIS), has followed this trend with numerous online testing and assessment activities during the 2021-2022 period. These activities assess learners' language learning progress and proficiency via different tests. To evaluate the strengths and weaknesses of online testing and assessment during the period, the researchers surveyed more than one hundred test administrators and examiners on their opinions and experiences in virtual exams. The participants shared valuable information on their experiences with the online system and their beliefs on the advantages and drawbacks of online at-home assessments. As a result, the research project can develop and later expand its sample as well as utilize other data collection methods to gain multi-dimensional information.

Abstract: This paper presents the results of research on the adsorption capacity of La3+ ions from aqueous solution of nanotube-type halloysite. The influence of operational conditions such as contact time, initial concentration of La3+, initial pH of solution, halloysite mass and temperature on the adsorption of La3+ had also been examined. The results show that the optimal efficiency and adsorption capacity of La3+ reached 90.19% and 3.76 mg/g in the suitable conditions: haloysite mass 0.6 g/50 mL solution, initial La3+ ion concentration 50 mg/L, pH 5.8, contact time 60 minutes at room temperature (25oC). The adsorption isotherm was studied based on both Langmuir and Freundlich models. The adsorption kinetics were studied by both pseudo-first-order and pseudo-second-order kinetic models. These results open up prospects for the application of haloysite clay minerals to remove and recover La in polluted water.