https://tapchikhcnnd.com.vn/index.php/tckhcnnd/issue/feed 2025-05-09T14:58:59+00:00 TẠP CHÍ KHOA HỌC VÀ CÔNG NGHỆ NHIỆT ĐỚI tapchikhcnnd@vrtc.org.vn Open Journal Systems <p>Tạp ch&iacute; Khoa học v&agrave; C&ocirc;ng nghệ nhiệt đới (Tạp ch&iacute;) l&agrave; tạp ch&iacute; khoa học chuy&ecirc;n ng&agrave;nh (t&ecirc;n quốc tế l&agrave; Journal of Tropical Science and Engineering) do Trung t&acirc;m nhiệt đới Việt &ndash; Nga l&agrave; cơ quan chủ quản. Tạp ch&iacute; l&agrave; nơi c&ocirc;ng bố, giới thiệu c&aacute;c c&ocirc;ng tr&igrave;nh nghi&ecirc;n cứu khoa học trong lĩnh vực khoa học v&agrave; c&ocirc;ng nghệ nhiệt đới v&agrave; c&aacute;c ng&agrave;nh c&oacute; li&ecirc;n quan phục vụ nghi&ecirc;n cứu khoa học, chuyển giao c&ocirc;ng nghệ v&agrave; đ&agrave;o tạo c&aacute;n bộ. B&ecirc;n cạnh đ&oacute;, Tạp ch&iacute; c&ograve;n l&agrave; một k&ecirc;nh, một phương tiện hữu hiệu để quảng b&aacute; h&igrave;nh ảnh của Trung t&acirc;m Nhiệt đới Việt &ndash; Nga, một cơ quan nghi&ecirc;n cứu khoa học đa ng&agrave;nh, đa lĩnh vực c&oacute; sự hợp t&aacute;c với nước ngo&agrave;i.</p> https://tapchikhcnnd.com.vn/index.php/tckhcnnd/article/view/193 2025-05-08T14:04:45+00:00 Nguyễn Thị Thu Lý Trần Đình Phiên Nguyễn Thị Thu Nguyễn Đức Thắng

DETERMINATION OF DIOXIN/FURAN AND DL-PCB IN ANIMAL FEED USING GAS CHROMATOGRAPHY TRIPLE QUADRUPOLE MASS SPECTROMETRY (GC-MS/MS) This study presents a method for ultra-trace analysis of polychlorinated dibenzo-p-dioxin/dibenzofuran (PCDD/Fs) and dioxin-like polychlorinated biphenyls (dl-PCBs) in animal feed using gas chromatography triple quadrupole mass spectrometry (GC-MS/MS). The GC-MS/MS system has a good capability to separate the isomers of PCDD/F and dl-CB, with the overlap level of TCDD isomers not exceeding 30%, meeting the analytical requirements of US EPA Method 1613B and 16130. The linear range of the calibration curve is 0.05-40 pg/µL for TCCD/F, 0.25-200 pg/µL for PeCDD/F-HpCDD/F, 0.5-400 pg/µL for OCDD/F, and 0.2-2000 pg/µL for dl-PCB. The method demonstrated detection limits of 0.005-0.076 pg/g for PCDD/Fs and 0.025-0.050 pg/g for dl-PCBs. Samples analysis revealed that the total toxic equivalency (TEQ) of PCDD/Fs and dl-PCBs in animal feed samples ranged from 0.197 to 0.418 pg TEQ/g, which is below the maximum allowable limits set by the European Commission for animal feed. These findings validate the applicability of GC-MS/MS as a reliable confirmatory tool for qualitifying PCDD/Fs and dl-PCBs in complex feed matrices.

2025-05-08T00:00:00+00:00 Copyright (c) 2025 https://tapchikhcnnd.com.vn/index.php/tckhcnnd/article/view/194 2025-05-08T14:15:37+00:00 Lê Thị Lan Anh ZH.A. Kasyan E.A. Chumachkova I.N. Sharova A. M. Porshakov Võ Viết Cường Trịnh Văn Toàn Đào Nguyên Mạnh Bùi Thị Thanh Nga Đặng Thị Việt Hương Nguyễn Ngọc Tân Lê Văn Quang

SEROLOGICAL SURVEY OF DENGUE VIRUS, HANTAVIRUS AND CHIKUNGUNYA VIRUS ANTI ANTIBODIES IN RESIDENTS OF SOME DISTRICTS OF HA GIANG AND LAI CHAU PROVINCES Objectives: To assess the serological prevalence of Dengue virus, Hantavirus and Chikungunya virus in residents of some districts of Lai Chau and Ha Giang provinces. Research methods: Serum samples were collected from residents living in Lai Chau and Ha Giang, using ELISA method to detect and evaluate prevalence of viruses. Results: Among the 294 serum samples collected from Lai Chau and Ha Giang, there were 140 samples from Lai Chau, and 154 samples were from Ha Giang, in which more than half (56.46%) were female. Analysis of age characteristics of participants showed that the median age was 46.5 years, with 49.32% aged ≥ 45 years and 18-44 years age group accounts for 50.68%. Among the positive serum samples for the viruses, Lai Chau was 21.4% higher than Ha Giang (16.9%); The prevalence of each virus species showed that Dengue virus accounted for the highest rate of 11.2%, followed by Hantavirus accounts for 6.1%, and Chikungunya virus accounts for 1.7%. In addition, there were four cases of co-infection, including two cases of co-infection with Dengue virus and Hantavirus and two cases of Dengue virus and Chikungunya virus. The seropositivity note for Dengue virus in the 18-44 age group was 2.2 times higher than in the ≥ 45 age group. The seropositivity rate for Hantavirus in women was 3.9 times higher than in men. There was no relationship about seropositivity for Chikungunya virus and age or gender. Conclusions: The seroprevalence characteristics of the three viruses differed by area, gender, and age.

2025-05-08T00:00:00+00:00 Copyright (c) 2025 https://tapchikhcnnd.com.vn/index.php/tckhcnnd/article/view/195 2025-05-08T14:31:48+00:00 Vũ Thanh Tùng Trịnh Minh Việt Nguyễn Nhật Linh Đỗ Tuấn Mến Lê Thanh Hoàng Nguyễn Thị Thảo Lưu Minh Đức Nguyễn Thị Trung Trần Thanh Tuấn Nguyễn Mạnh Đạt Đỗ Thị Tuyên dttuyen@ibt.ac.vn

SCREENING OF LOVASTATIN PRODUCTION - AN HMG-CoA REDUCTASE INHIBITOR - BY Rhizopus sp. STRAINS ISOLATED IN VIETNAM In this study, several Rhizopus sp. strains isolated from Vietnamese yeast bread samples were screened for their ability to produce lovastatin, an inhibitor of HMG-CoA reductase, using thin-layer chromatography (TLC). A solvent system of dichloromethane and ethyl acetate (70:30, v/v) revealed that two strains, Rhizopus sp. BMM 313 and Rhizopus sp. 5280, produced lovastatin. This conclusion was supported by the alignment of their TLC bands with a lovastatin standard (Sigma), exhibiting a retention factor (Rr) value of 0.57. Based on colony morphology and microscopic characteristics observed via scanning electron microscopy (SEM), Rhizopus sp. 5280 was reclassified as R. microsporus 5280. High-performance liquid chromatography (HPLC) analysis demonstrated that R. microsporus 5280 achieved the highest lovastatin yield at 34.59 mg/L. To optimize lovastatin production and investigate other secondary metabolites with HMG-CoA reductase inhibitory activity, this strain will be further studied to refine growth conditions and medium composition.

2025-05-08T00:00:00+00:00 Copyright (c) 2025 https://tapchikhcnnd.com.vn/index.php/tckhcnnd/article/view/196 2025-05-08T14:45:17+00:00 Nguyễn Huy Hoàng Trần Danh Tiến Thịnh

EVALUATION OF THE EFFECTIVENESS OF HYPERBARIC OXYGEN THERAPY IN IMPROVING COGNITIVE FUNCTION IN PATIENTS WITH MILD AND MODERATE ALZHEIMER’S DISEASE Objective: To evaluate the effectiveness of hyperbaric oxygen therapy (HBOT) in improving cognitive function in patients with mild and moderate Alzheimer’s disease. Subjects and Methods: A randomized controlled clinical trial was conducted on 90 patients with mild to moderate Alzheimer’s disease, including 60 patients in the HBOT group and 30 patients in the control group who received Tanakan 40 mg. Cognitive function was assessed using the MMSE score before treatment and after 20, 40 and 60 sessions. The HBOT group underwent therapy in a hyperbaric oxygen chamber at a pressure of 2.0 ATA, for 60-70 minutes per session, with 5 sessions per week. Results: The study results indicate that the hyperbaric oxygen therapy group showed significant improvement in MMSE scores after 20 sessions of treatment and with optimal effects archieved after at least 40 sessions. The average MMSE score increased from 19.0 to 22.4 points. The proportion of patients classified at the mild stage increased from 48.3% to 82.5%, and 2.5% reached a normal cognitive level. In contrast, the Tanakan 40 mg group showed no statistically significant changes in MMSE scores (p>0.05) after 60 days of treatment. Conclusion: Hyperbaric oxygen therapy demonstrates superior effectiveness in improving cognitive function in patients with mild and moderate Alzheimer’s disease, particularly after 40 and 60 sessions of treatment. This method shows promise as a potential intervention for Alzheimer’s disease.

2025-05-08T00:00:00+00:00 Copyright (c) 2025 https://tapchikhcnnd.com.vn/index.php/tckhcnnd/article/view/197 2025-05-08T14:52:44+00:00 Nguyễn Trọng Hiệp Vũ Thị Minh Châu Lê Đức Mạnh Mai Quang Tuyến Nguyễn Đức Thịnh Trần Thị Lệ Thu Lê Minh Tuấn Nguyễn Ngọc Phương Nguyễn Lê Kim Phụng

MONITORING AND RISK ASSESSMENT OF POLYCYCLIC AROMATIC HYDROCARBON IN LOWER MEKONG BASIN SEDIMENTS A total of 61 sediment samples were collected from 22 locations along the Mekong River basin in Tien Giang, Ben Tre, Dong Thap and An Giang provinces. The correlation coefficient (R2) for each polycyclic aromatic hydrocarbon (PAH) was exceeded 0.995 with repeatability ranging from 5.7% to 12.5%, reproducibility from 9.4% to 12.8%, and process recovery rates between 82.8% and 114.6%. In addition, the detection limits of individual PAH ranged from 3.05 μg/kg to 37.8 μg/kg. The total content of 18 PAHs in sediment samples ranged from 27.6 µg/kg to 2,018 µg/kg, of which the majority were non-carcinogenic PAH (NCPAH) with concentrations of less than 622 µg/kg, while carcinogenic PAH (CPAH) accounted for a smaller proportion with concentrations under 572 μg/kg. The PAH4 group consisting of Benzo(a)pyrene, Benzo(a)anthracene, Benzo(b)fluoranthene, and Chrysene was deteted at low concentrations ranging from non-detectable levels to 560 μg/kg. Furthermore, the analysis at PAH composition in the sediment samples revealed that 2- to 3-ring aromatic PAHs were the most prevalent, constituting 46.22% of the total, followed by 4-ring aromatic PAHs at 31.4%. The environmental risk factor associated with PAH accumulation in the sediments was calculated to be below 0.75, indicating that the levels remain within the environmentally safe threshold.

2025-05-08T00:00:00+00:00 Copyright (c) 2025 https://tapchikhcnnd.com.vn/index.php/tckhcnnd/article/view/198 2025-05-08T15:04:56+00:00 Nguyễn Thị Mỹ Lệ Lê Việt Hoàng Nguyễn Duy Tới Đinh Mai Vân Đinh Thuý Hằng dthangimbt@gmail.com Nguyễn Thị Hải

APPLICATION OF BENEFICIAL BACTERIA TO IMPROVE AGRICULTURAL SOIL QUALITY Two bacterial strains, VK7 and SDT2.3, possess multiple biological activities beneficial to plants, including IAA production, siderophore synthesis, nitrogen fixation, EPS production, and phosphate solubilization. These strains are expected to have potential applications for improving agricultural soil quality. Based on comparisons of 16S rDNA sequences and rpoB gene sequences, these bacterial strains were identified as Bacillus velezensis VK7 and Ensifer sesbaniae SDT2.3. A bioformulation containing live cells of two strains VK7 and SDT2.3 was tested on degraded soil from a tea-cultivated farm with tomato plants under greenhouse conditions. After one crop season (4 months), soil properties improved significantly: total organic carbon increased by 16.51% and sand content in the soil mechanical composition rose by 120.11%. Enhanced soil quality was further evidenced by a 15.70% increase in green biomass (stem and leaf weight) compared to untreated control. Notably, the combined application of both bacterial strains reduced NPK fertilizer usage by 10% compared to conventional methods, with no adverse effects on plant growth or yield.

2025-05-08T00:00:00+00:00 Copyright (c) 2025 https://tapchikhcnnd.com.vn/index.php/tckhcnnd/article/view/202 2025-05-09T14:20:55+00:00 Nguyễn Khắc Thanh Trần Thị Minh Trang Phạm Hồng Thái Bùi Xuân Thành Phạm Thị Ngọc Mai

ADSORPTION CHARACTERISTICS OF NO3- ON AMINE GRAFTED ACTIVATED CARBON USING APTES In this study, activated carbon was amine-grafted with (3-Amineopropyl) triethoxysilane (APTES) for nitrate adsorption enhancement. Material characterizations by SEM, F-TIR, EDS, Zeta potential measurement, etc. demonstrated the successful amine graft on the activated carbon surface, leading to a charge reversal of the material surface from negative to positive and a superior increase in the NO3- adsorption capacity in comparison with that of bare activated carbon. At the optimal conditions: pH 7, adsorption time of 60 minutes, and adsorbent material of 0.05g, the maximum adsorption capacity of the modified material is relatively high, qmax = 55.21 mg/g. The adsorption of NO3- on the material followed the Langmuir isotherm model and pseudo-second-order kinetics, suggesting that the adsorption included both physical and chemical adsorption processes. When desorbed with 0.5M HCl as the eluting solution, the material could be reused at least 5 times with an adsorption efficiency of ~ 80%. The synthesized material was applied to remove NO3- in some lake water samples in Hanoi with a removal efficiency of ~ 95%.

2025-05-09T00:00:00+00:00 Copyright (c) 2025