Phytoplankton composition in intensive shrimp ponds in Bac Lieu province, Vietnam

Algal overgrowth in shrimp culture ponds can affect the quality of the aquatic environment, thereby adversely affecting the shrimp and causing economic losses. The objective of this study was to evaluate the variation in phytoplankton composition in intensive shrimp ponds in Bac Lieu province, Vietnam. Phytoplankton samples were collected in three black tiger shrimp (Penaeus monodon) ponds and three whiteleg shrimp (Litopenaeus vannamei) ponds. The collected data were analyzed using SPSS and canonical correlation analysis softwares. In total, 75 species of phytoplankton were recorded in black tiger shrimp ponds and 64 species in whiteleg shrimp ponds. Diatoms had the highest species diversity with 29–30 species (39%–47%), followed by green algae with 9–19 species (14%–25%); species numbers of other phyla varied from 5–12 (8%–16%). The total number of phytoplankton species throughout the study varied from 34–50 species. Algal density was relatively high and ranged from 497,091–2,229,500 ind./L and 1,301,134–2,237,758 ind./L in black tiger shrimp and whiteleg shrimp ponds, respectively. The diatom density tended to increase during the final stage of the production cycle in black tiger shrimp ponds. Blue-green algae and dinoflagellates also increased in abundance at the end of the cycle, which can affect shrimp growth. Diatoms were significantly positively correlated with pH, salinity, total ammonia nitrogen, and nitrate (NO3–) concentrations (p < 0.05). Blue-green algae and dinoflagellates were positively correlated with salinity, phosphate (PO43–), and NO3–. Algal species diversity was lower in the whiteleg shrimp ponds than in the black tiger shrimp ponds. Several dominant algal genera were recorded in the shrimp ponds, including Nannochloropsis, Gyrosigma, Chaetoceros, Alexandrium, and Microcystis. The results of this study provide basic data for further investigations, and they contribute to the management of algae in brackish-water shrimp ponds

ADULT LEARNERS’ CHARACTERISTICS: TEACHERS’ PERCEPTION AND CORRESPONDING INSTRUCTIONAL STRATEGIES - A CASE IN A POLITICAL ACADEMY IN VIETNAM

Gaining an insightful understanding of what types of characteristics adult learners are and what instructional strategies would be appropriate for them in order to help foster their learning, this quantitative study, in a context of a political academy in Vietnam, was employed to achieve such aims. A survey questionnaire was used to collect data from 46 politics lecturers. The findings showed that the teacher participants appreciated their adult learners’ understanding of why they must learn further (M=4.33) and rich living experiences (M=4.30). Besides, the lecturers were highly perceived to be in charge of encouraging their adult learners to keep involved in their learning process (M=4.54). The study also provided its readers with several implications for fostering their understanding of adult learners, their characteristics, and their needs as well.  Article visualizations

KHẢ NĂNG SỬ DỤNG BÃ MÍA TRONG SẢN XUẤT CHẤT BÉO TỪ NẤM MEN YARROWIA LIPOLYTICA PO1G

Nghiên cứu này nhằm khảo sát khả năng sử dụng bã mía để nuôi cấy nấm men Yarrowia lipolytica Po1g nhằm thu được chất béo. Sau khi được xử lí sơ bộ, bã mía được chuyển hóa thành đường bằng phương pháp thủy phân với H2SO4 loãng ở nồng độ (1 - 4%), nhiệt độ (60 - 120°C), và thời gian (1- 8 giờ). Kết quả cho thấy nồng độ đường tổng tăng tỉ lệ thuận với nồng độ acid, thời gian, và nhiệt độ thủy phân. Nồng độ đường tổng cao nhất thu được khi bã mía được thủy phân bằng H2SO4 3% ở 90oC trong 6 giờ và với tỉ lệ bã mía và dung dịch acid là 1/25 g/mL. Quá trình nuôi cấy nấm men Y. lipolytica Po1g cho thấy sản phẩm thủy phân bã mía đã khử độc cho kết quả tăng trưởng sinh khối là cao nhất (12.07 g/L) so với D-glucose (10.3 g/L) và D-xylose (8.45 g/L). Hàm lượng chất béo cao nhất thu được khi nấm men được nuôi cấy trong bã mía thủy phân có nồng độ đường tổng 30 g/L là 46.7%

Adsorptive Removal of Rhodamine B Using Novel Adsorbent-Based Surfactant-Modified Alpha Alumina Nanoparticles

The objective of the present study is to investigate removal of cationic dye, rhodamine B (RhB), in water environment using a high-performance absorbent based on metal oxide nanomaterials toward green chemistry. The adsorption of sodium dodecyl sulfate (SDS) onto synthesized alpha alumina (α-Al2O3) material (M0) at different ionic strengths under low pH was studied to fabricate a new adsorbent as SDS-modified α-Al2O3 material (M1). The RhB removal using M1 was much higher than M0 under the same experimental conditions. The optimal conditions for RhB removal using M1 were found to be contact time 30 min, pH 4, and adsorbent dosage 5 mg/mL. The maximum RhB removal using M1 achieved 100%, and adsorption amount reached 52.0 mg/g. Adsorption isotherms of RhB onto M1 were well fitted by the two-step adsorption model. The electrostatic attraction between positive RhB molecules and negatively charged M1 surface controlled the adsorption that was evaluated by the surface charge change with zeta potential and adsorption isotherms. Very high RhB removal of greater than 98% after four regenerations of M1 and the maximum removal for all actual textile wastewater samples demonstrate that SDS-modified nano α-Al2O3 is a high-performance and reusable material for RhB removal from wastewater

High Prevalence of Infection Among School-Aged Children in Ho Chi Minh City, VietNam.

OBJECTIVES: There is no study on Helicobacter pylori (H. pylori) infection in pupils of Ho Chi Minh city (HCMC), the most overcrowded city in Vietnam. Therefore, the aim of this study was to estimate the prevalence of H. pylori and its geographical spread among school-aged children. METHODS: A school-based cross-sectional study was conducted among 1854 pupils across 24 districts of HCMC in 2019. Multiple-stage sampling method was used to enroll pupils. We built a four-points index for geographical division based on population density and employees density to evaluate the link between H. pylori and crowded level. Stool samples were analyzed by monoclonal enzyme-immunoassay stool antigen-test to assess the infection status. Logistic regression was performed to assess possible factors related to H. pylori infection. RESULTS: The overall prevalence of H. pylori was 87.7%. There was a linear increasing trend in the infection rate (p < 0.001) across the 4-points index of HCMC and this trend maintained within both age and gender subgroups (p = 0.02). CONCLUSION: Prevalence of H. pylori was high and it increased with population density or employees density. Therefore, it is crucial to plan and implement the reduction of H. pylori infection programs by targeting the highly concentrated population areas of HCMC

A real-world cohort study of first-line afatinib in patients with EGFR-mutant advanced non-small cell lung cancer in Vietnam

Abstract Background This study aimed to evaluate the efficacy and side effects of first-line afatinib treatment in a real-world setting in Vietnam. Methods This retrospective study was conducted across nine hospitals in Vietnam. Advanced epidermal growth factor receptor (EGFR)-mutant non-small cell lung cancer (NSCLC) patients who received afatinib as first-line therapy between April 2018 and June 2022 were included, and patient medical records were reviewed. Key outcomes were overall response rate (ORR), time-to-treatment failure (TTF), and tolerability. Results A total of 343 patients on first-line afatinib were eligible for the study. EGFR exon 19 deletion (Del19) alone was detected in 46.9% of patients, L858R mutation alone in 26.3%, and other uncommon EGFR mutations, including compound mutations, in 26.8%. Patients with brain metastases at baseline were 25.4%. Patients who received 40 mg, 30 mg, and 20 mg as starting doses of afatinib were 58.6%, 39.9%, and 1.5%, respectively. The ORR was 78.1% in the overall population, 82.6% in the Del19 mutation subgroup, 73.3% in the L858R mutation subgroup, and 75.0% in the uncommon mutation subgroup (p > 0.05). The univariate and multivariate analyses indicate that the ORR increased when the starting dose was 40 mg compared to starting doses below 40 mg (83.9% vs. 74.3%, p = 0.034). The median TTF (mTTF) was 16.7 months (CI 95%: 14.8–18.5) in all patients, with a median follow-up time of 26.2 months. The mTTF was longer in patients in the common EGFR mutation subgroup (Del19/L858R) than in those in the uncommon mutation subgroup (17.5 vs. 13.8 months, p = 0.045) and in those without versus with brain metastases at baseline (17.5 vs. 15.1 months, p = 0.049). There were no significant differences in the mTTF between subgroups based on the starting dose of 40 mg and  0.05). The most common treatment-related adverse events (any grade/grade ≥ 3) were diarrhea (55.4%/3.5%), rash (51.9%/3.2%), paronychia (35.3%/5.0%), and stomatitis (22.2%/1.2%). Conclusions Afatinib demonstrated clinical effectiveness and good tolerability in Vietnamese EGFR-mutant NSCLC patients. In our real-world setting, administering a starting dose below 40 mg might result in a reduction in ORR; however, it might not have a significant impact on TTF

An observational study of breakthrough SARS-CoV-2 Delta variant infections among vaccinated healthcare workers in Vietnam

Background Data on breakthrough SARS-CoV-2 Delta variant infections in vaccinated individuals are limited. Methods We studied breakthrough infections among Oxford-AstraZeneca vaccinated healthcare workers in an infectious diseases hospital in Vietnam. We collected demographic and clinical data alongside serial PCR testing, measurement of SARS-CoV-2 antibodies, and viral whole-genome sequencing. Findings Between 11th–25th June 2021 (7-8 weeks after the second dose), 69 staff tested positive for SARS-CoV-2. 62 participated in the study. Most were asymptomatic or mildly symptomatic and all recovered. Twenty-two complete-genome sequences were obtained; all were Delta variant and were phylogenetically distinct from contemporary viruses obtained from the community or from hospital patients admitted prior to the outbreak. Viral loads inferred from Ct values were 251 times higher than in cases infected with the original strain in March/April 2020. Median time from diagnosis to negative PCR was 21 days (range 8–33). Neutralizing antibodies (expressed as percentage of inhibition) measured after the second vaccine dose, or at diagnosis, were lower in cases than in uninfected, fully vaccinated controls (median (IQR): 69.4 (50.7-89.1) vs. 91.3 (79.6-94.9), p=0.005 and 59.4 (32.5-73.1) vs. 91.1 (77.3-94.2), p=0.043). There was no correlation between vaccine-induced neutralizing antibody levels and peak viral loads or the development of symptoms. Interpretation Breakthrough Delta variant infections following Oxford-AstraZeneca vaccination may cause asymptomatic or mild disease, but are associated with high viral loads, prolonged PCR positivity and low levels of vaccine-induced neutralizing antibodies. Epidemiological and sequence data suggested ongoing transmission had occurred between fully vaccinated individuals