https://dthujs.vn/index.php/nsen Dong Thap University Journal of Science en-US Natural Sciences Issue https://dthujs.vn/index.php/nsen/article/view/2406 In this paper, we classify all indecomposable 8-dimensional solvable Lie algebras whose nilradical is the 7-dimensional Heisenberg algebra. Our method is based on the observation that any solvable Lie algebra can be viewed as an extension of its nilradical , namely, the maximal nilpotent ideal of . Using standard techniques from Lie theory, we begin with the 7-dimensional Heisenberg algebra and classify all 8-dimensional algebras that admit it as their nilradical. PhD. Thi Mong Tuyen Nguyen Sinh viên Quoc Thai Pham Sinh viên Phuoc Hieu Pham Sinh viên Pham Minh Tien Thieu Copyright (c) 2025 Dong Thap University Journal of Science https://creativecommons.org/licenses/by-nc/4.0 https://dthujs.vn/index.php/nsen/article/view/2672 Among different material families, oxide hydroxides have emerged as promising cadidates for different advanced applications. In this paper, the synthesis of Boehmite (g-AlOOH) powder via the hydrothermal technique and the influence of annealing temperature and duration on its crystal structure is reported. Different annealing temperatures (100, 200 and 300oC) and durations (1, 2, and 3 hours) were applied on synthesized AlOOH powder. The crystal structure and crystallite size of the samples were evaluatedvia X-ray diffraction patterns. The proportion of atoms in the powder sample was ascertained utilizing Energy Dispersive X-ray Spectroscopy. The sample's molecular compositionswere meticulously investigated using Fourier-transform infrared spectroscopy. Experimental results indicate that AlOOH generated via the hydrothermal technique exhibits crystallite sizes between 8.27 nm and 15.31 nm. The 300 °C samples have the highest particle size and minimal microstrain, signifying a solid crystal structure with few imperfections. Thi Hong Nhung Nguyen Nguyen Duy Nguyen Bao Quan Tran Bao Khang Thach Bich Diep T. Pham PhD Thanh Hoa Pham PhD Thi Kim Hang Pham Doctor Hai Dang Ngo Copyright (c) 2025 Dong Thap University Journal of Science https://creativecommons.org/licenses/by-nc/4.0 https://dthujs.vn/index.php/nsen/article/view/2665 This study was conducted to evaluate the effects of pasteurization temperature and holding time on the quality of red-flesh dragon fruit (Hylocereus polyrhizus) - strawberry (Fragaria × ananassa) juice. The juice was blended at a ratio of 7:3 (v/v), treated with pectinase enzyme, supplemented with sugar and ascorbic acid, and subsequently pasteurized at three temperature levels (80, 85, and 90 °C) for corresponding holding times (3, 5, and 7 minutes). The evaluated parameters included pasteurization unit (PU), inhibition efficiency against aerobic bacteria, yeasts, and molds, betacyanin and vitamin C content, as well as sensory quality. The results demonstrated that both pasteurization temperature and holding time had significant impacts on all examined criteria. Among the tested conditions, pasteurization at 85 °C for 5 minutes achieved a PU ≥ 5, ensured microbiological safety, and preserved the characteristic color, natural aroma, and high nutritional value of the product. Therefore, this condition was identified as optimal for producing red-flesh dragon fruit - strawberry juice with desirable sensory properties, high nutritional retention, and appropriate microbiological stability. Master Xuân Hồng Nguyễn Ths Phuong Linh Nguyen Thi Ngoc Thao Bui Ths Thi Hong Xuyen Nguyen Tan Kha Nguyen Hieu Ky Ngo Copyright (c) 2025 Dong Thap University Journal of Science https://creativecommons.org/licenses/by-nc/4.0 https://dthujs.vn/index.php/nsen/article/view/2670 This paper is devoted to the study of stable strong duality for composed convex optimization problems with composed constraints. To this end, we establish generalized Farkas-type results and provide characterizations for inequality systems involving composed convex functions under composed constraints. These results extend several existing results in convex and nonconvex programming. In particular, we introduce a sufficient condition ensuring generalized Farkas-type results in the composite setting. The obtained results are then applied to derive strong and stable strong duality for composed convex optimization problems with composed constraints, as well as optimality conditions for the aforementioned problem. As illustrations of the results, we present some consequences and applications to special cases. TS Hai Long Dang Hồng Mơ Trần Copyright (c) 2025 Dong Thap University Journal of Science https://creativecommons.org/licenses/by-nc/4.0 https://dthujs.vn/index.php/nsen/article/view/2613 This study presents the development of a multiplex PCR assay for the simultaneous detection of two major shrimp pathogens. In Vietnam, the co-culture of shrimp and fish in the same pond increases the risk of shrimp infection due to cross-contamination from fish waste, feed, and environmental sources, contributing to disease outbreaks and shrimp mortality rates exceeding 80%. This study aimed to detect Vibrio parahaemolyticus and Aeromonas veronii, two major etiological agents associated with Acute Hepatopancreatic Necrosis Disease (AHPND)/Early Mortality Syndrome (EMS) in Litopenaeus vannamei, using a multiplex polymerase chain reaction (PCR) technique. Two gene fragments, GSTT2 and pepO, were selected as species-specific molecular markers for V. parahaemolyticus and A. veronii, respectively. Multiplex PCR successfully amplified both target genes with clear and specific bands (236 bp for GSTT2, 520 bp for pepO) without cross-reactivity with other bacterial species. These results confirm the reliability and specificity of the method, offering a rapid and accurate diagnostic tool for bacterial diseases in shrimp farming, thereby contributing to improved disease management and sustainable aquaculture development in Vietnam. Thang-Loi Thi Ngo Kim-Ngan Ngoc Nguyen Lam-Ha Nguyen Lan-Anh Tran Dinh Đình Chương Phạm Copyright (c) 2025 Dong Thap University Journal of Science https://creativecommons.org/licenses/by-nc/4.0 https://dthujs.vn/index.php/nsen/article/view/2438 The paper shows experiments of 13 samples with three repeat times, indicating the effect of temperature and salinity in a Nitrogen-slurry ice solution on Purple-Spotted Bigeye (Priacanthus tayenus) protein rate. The result shows that the protein Quadratic model is significant with a p-value of less than 0.05. The temperature affects strongly the protein rate of the samples during preservation by the Nitrogen-slurry ice solution. The equation of protein related to temperature and salinity was Protein rate equals to -12,57 - 21,79xT + 1,15xS-4,57xTxS-6,65xTxT - 0,02xSxS (where T is Temperature, S is Salinity). The protein rate of the fish was kept at 19.9% during 07 days in storage solution with temperature of -1.5 oC and salinity of 25‰ (the fish was stored in normal ice 4 days onboard before keeping in the experiment solution). The experiment suggested that, after landing from fishing boats, the Purple-Spotted Bigeye (Priacanthus tayenus) can preserve in the Nitrogen-slurry ice of temperature range from -1.4 oC to -1.9 oC and salinity from 22‰ to 28‰ from in least 07 days to remain acceptable rate of protein. Xuan Hung Dinh Copyright (c) 2025 Dong Thap University Journal of Science https://creativecommons.org/licenses/by-nc/4.0 1 11 https://dthujs.vn/index.php/nsen/article/view/2885 In this paper, the Fenton-type oxidation of phenol over Mn-Fe/diatomite catalyst was studied. The Mn-Fe/diatomite composite was synthesised by using a hydrothermal process from a colloidal solution containing Mn(II), Fe(III), and diatomite. Under suitable synthesis conditions, the obtained Mn-Fe/diatomite contained 6.23% Fe and 0.10% Mn (by mass) with a specific surface area of ​​53.2 m2/g. Phenol conversion can reach 99% after 240 minutes of reaction on the Mn-Fe/diatomite catalyst (under the following conditions: phenol concentration 1 g/L; catalyst content 1 g/L; H2O2 content 6.5 g/L; reaction temperature 50°C). The bimetallic Mn-Fe/diatomite catalyst has lower oxidation activity than the monometallic Fe/diatomite catalyst but higher durability and reusability. PGS. TS Dinh Du Pham Thanh Danh Huỳnh Copyright (c) 2025 Dong Thap University Journal of Science https://creativecommons.org/licenses/by-nc/4.0 https://dthujs.vn/index.php/nsen/article/view/2473 This study was conducted to assess the diversity of vascular plants at the President Ho Chi Minh Memorial Area in Ca Mau Province, serving as a scientific basis for the effective exploitation, use, management, and conservation of plant resources in this area. The research results identified 145 species of vascular plants, belonging to 124 genera, and 64 families across four divisions: Ferns (Polypodiophyta), Cycads (Cycadophyta), Pines (Pinophyta), and Magnolias (Magnoliophyta). The life forms of the vascular flora here consist of 5 main groups (Phanerophytes - Ph, Chamaephytes - Ch, Hemicryptophytes - Hm, Cryptophytes - Cr, Therophytes - Th), with Biological Spectrum of the vascular flora 60.0 Ph + 7.59 Ch + 4.83 Hm + 9.65 Cr + 17.93 Th. The utility value of vascular plants was recorded across 10 usage groups, with 135 species used for medicinal purposes accounting for 93.10%, 108 species used for ornamental purposes accounting for 74.48%, edible plants ranking third with 50 species accounting for 34.48% and other uses. The flora in this area includes 3 species with conservation value, with 1 species is classified as Vulnerable (VU) assessed according to the Vietnam Red Data Book (2024), 1 species Vulnerable (VU) according to the Viet Nam Red List of Threatened Species (2024), 1 species listed in Decree 84/2021/ND-CP (2021). Thi Thanh Mai Pham Trong Duy Pham Phuc Thinh Huynh Copyright (c) 2026 Dong Thap University Journal of Science https://creativecommons.org/licenses/by-nc/4.0 https://dthujs.vn/index.php/nsen/article/view/2933 Oldenlandia corymbosa (family Rubiaceae) has been long used in traditional medicine for the treatment of various ailments such as fever, hepatitis, gastrointestinal disorders, cancer, and other inflammatory conditions. Numerous compounds isolated from this species have been reported to exhibit notable pharmacological activities, including anti-inflammatory, antioxidant, anticancer, immunomodulatory, and neuroprotective effects. In the present study, the antibacterial activity of different solvent fractions of O. corymbosa was evaluated to identify promising extracts for further phytochemical investigation. The ethyl acetate fraction showed the strongest inhibitions against Vibrio sp. and Aeromonas caviae, with particularly high inhibition against Vibrio sp. (86.78 ± 0.24 mm at 5.000 mg/mL). Chemical analysis of the ethyl acetate fraction was performed using silica gel column chromatography, and the chemical structures were elucidated by NMR spectroscopy through comparison with reference data, leading to the identification of three compounds: geniposide (1), rutin (2), and quercetin (3). These findings highlight the potential of O. corymbosa as a promising natural source of antibacterial agents. TS. Thi Bach Le Minh Nhut Nguyen Tan Tai Le TS Thi Thanh Xuan Le Tien Phong Nguyen Nguyen Hong Phuoc Le Hoang Phi Do Tran Nhat Anh Nguyen Thi Hoai Thu To Viiet Hoang Nguyen Van Dat Nguyen Copyright (c) 2026 Dong Thap University Journal of Science https://creativecommons.org/licenses/by-nc/4.0 1 10 https://dthujs.vn/index.php/nsen/article/view/2903 Muntingia calabura fruit contains numerous phytochemicals with medicinal value; however, its utilization remains limited due to rapid ripening and poor storability. Fermentation using Saccharomyces cerevisiae is considered a promising approach to extend shelf life and preserve bioactive compounds. This study aimed to evaluate the phytochemical composition and antioxidant activity of fermented extracts from ripe M. calabura fruits. Phytochemical screening, the Folin–Ciocalteu method (for total phenolic content), the aluminum chloride colorimetric method (for total flavonoid content), and the DPPH radical scavenging assay were employed. The fermented product exhibited 8% ethanol, 8.5° Brix, and pH 4.0. The phytochemical constituents detected included saponins, polyphenols, cardiac glycosides, triterpenoids, and alkaloids. The total phenolic content was 95.87 ± 2.00 mg GAE/g, the total flavonoid content was 6.96 ± 0.21 mg QE/g, and antioxidant activity was expressed by an IC₅₀ value of 203.9 ± 1.0 µg/mL. Fermentation of M. calabura fruit with S. cerevisiae effectively preserved, demonstrating strong potential for the development of natural fermented beverages and functional food products derived from this tropical fruit. Thi Bich Duong Thanh Than Nguyen Ngoc Chau Trinh Duy Tan Nguyen Trong Vi Nguyen Trung Kien Pham Kim Ngoc Tri Ngoc Trung Dung Huynh Copyright (c) 2026 Dong Thap University Journal of Science https://creativecommons.org/licenses/by-nc/4.0 1 10 https://dthujs.vn/index.php/nsen/article/view/3182 This paper investigates the effect of temperature on the structural formation of Ga₀.₂N₀.₈ semiconductor materials. Temperature ranges from 300 K to 20 K were studied using molecular dynamics (MD) simulation. Results obtained after cooling showed the formation of several face-centered cubic (FCC), hexagonal close-packed (HCP), body-centered cubic (BCC), and amorphous (Amor) structures. These results provide a theoretical basis for future experimental studies and guide the application of Ga–N in low-temperature electronic devices. Trong Dung Nguyen Thi Phuong Hoang Van Hoang Ong Thi Duyen Tran Copyright (c) 2026 Dong Thap University Journal of Science https://creativecommons.org/licenses/by-nc/4.0 1 11 https://dthujs.vn/index.php/nsen/article/view/3285 Salinity acts as a key abiotic stress that hampers seed germination and early seedling growth. This study examined how salinity affects germination and initial development in Pak Choi (Brassica rapa subsp. chinensis L.) at electrical conductivity (EC) levels from 0 up to 16 dS m⁻¹. We measured parameters like germination percentage (GP), germination index (GI), mean germination time (MGT), T₅₀, seedling vigor index (SVI), shoot and root lengths, fresh and dry biomass, plus dry weight-to-length ratios. At mild salinity (EC ≤ 4 dS m⁻¹), GP stayed high at 91.8%, and seedlings actually developed better - with fresh weight achieving a maximum of 51.30 mg at EC 4 dS m⁻¹ (almost twice the control's 22.88 mg) and SVI-shoot topping surpassing 250—suggesting a favorable response to low-level salt stress. Germination time-related indices increased progressively with EC, with T₅₀ rising from 12.38 h at EC 0 to 27.02 h at EC 16 dS m⁻¹. Seedling growth and vigor declined sharply at EC 10 dS m⁻¹, growth and vigor dropped off quickly: shoot length fell from 3.2 cm to just 0.72 cm at EC 16 dS m⁻¹. Shoots suffered more than roots, and higher salinity boosted dry weight-to-length ratios (from 0.60 to 1.51 mg cm⁻¹), pointing to a change toward denser biomass rather than longer growth. Thus, these findings provide quantitative salinity thresholds for Pak choi at the germination and early seedling stage, offering practical references for agronomic management in saline-affected areas and a basis for selecting salt-tolerant genotypes within the Brassicaceae family. Thi Dan Thi Nguyen The Khang Tran Minh Nhut Trinh Lee Thao vy Pham Quoc Nam Lam Nhat Nam Nguyen Agustian Auguste Musliar Kasim Copyright (c) 2026 Dong Thap University Journal of Science https://creativecommons.org/licenses/by-nc/4.0 1 15 https://dthujs.vn/index.php/nsen/article/view/3176 Ludwigia peruviana, a member of the family Onagraceae, has been reported to possess various biological activities; however, information on its antioxidant properties and phytochemical composition remains limited. This study aimed to investigate the phytochemical constituents and evaluate the antioxidant activity as well as the total phenolic and flavonoid contents of the ethanolic extract of L. peruviana. Aerial parts of L. peruviana were collected in Can Tho City, Viet Nam, between October and November 2024 and extracted by ultrasonic-assisted extraction using 99% ethanol. The phytochemical constituents were determined by employing standard qualitative chemical tests. Antioxidant activity was evaluated using the DPPH radical scavenging assay, while total phenolic content (TPC) and total flavonoid content (TFC) were determined by the Folin–Ciocalteu method and the aluminum chloride colorimetric assay, respectively. This study demonstrated the occurrence of various secondary metabolites, including phenolics, flavonoids, alkaloids, tanins, fixel oil, carotenoids, saponins and triterpenoids. The ethanolic extract exhibited weak DPPH radical-scavenging activity, with an IC₅₀ value of 229.96 µg/mL. The TPC and TFC were 125.81 ± 7.99 mg GAE/g extract and 39.20 ± 0.49 mg QE/g extract, respectively. To the best of our knowledge, this is the first report on phytochemical composition, DPPH radical scavenging activity and phenolic–flavonoid contents of L. peruviana. These findings provide a scientific basis for further phytochemical investigations and evaluation of other biological activities of this species. Ba Duy Tran Ngo Thanh Trung Pham Ngo Bao Ngoc Pham Tu Nguyen Nguyen Quoc An Duong Minh Nhan Le Tram, Thi Thu Nguyen Copyright (c) 2026 Dong Thap University Journal of Science https://creativecommons.org/licenses/by-nc/4.0 1 11 https://dthujs.vn/index.php/nsen/article/view/3329 β-Ga₂O₃ nanorods were synthesized via a hydrothermal method followed by post-annealing at 910 oC in air, where reaction time strongly influences nanorod morphology. Longer hydrothermal durations increase the length of the nanorods but also induce their aggregation, whereas a reaction time of 7.5 h yields an optimal balance between increased nanorod length and reduced aggregation. After calcination at 910 oC, GaOOH is fully converted to monoclinic β-Ga₂O₃, with FTIR confirming Ga–O formation and reduced hydroxyl groups. The GO/β-Ga₂O₃ sensor was then fabricated using β-Ga₂O₃ powder, exhibiting stable switching under 254 nm illumination, with a responsivity of 2.06×10⁻² A W⁻¹ and response times of 1.6/2.7 s at 10 V. These results highlight the potential of β-Ga₂O₃ nanorods for UV sensing applications. Minh Dat Duong Dinh My Duyen Mai Tien Luat Nguyen Quynh-Anh Hoang-Nguyen Huy Binh Do Copyright (c) 2026 Dong Thap University Journal of Science https://creativecommons.org/licenses/by-nc/4.0 1 13 https://dthujs.vn/index.php/nsen/article/view/3387 This study aimed to develop a beverage from Pouzolzia zeylanica extract mixed with passion fruit juice and to identify the most suitable formulation and pasteurization conditions within the tested range in terms of sensory quality, retention of bioactive compounds, and microbiological safety. A completely randomized design was used to evaluate the effects of mixing ratio, sugar addition, citric acid addition, and temperature-time pasteurization. Among the tested formulations, the beverage with an 8:2 (v/v) ratio of P. zeylanica extract to passion fruit juice, 18% sugar, and 0.03% citric acid was selected as the most suitable formulation. This formulation achieved the highest sensory acceptance while maintaining relatively high contents of anthocyanins (1.81 mg/L), total polyphenols (4.15 mg GAE/mL), and vitamin C (8.56 mg/100mL). Pasteurization at 65 °C for 10 mins (PU = 18.57 min) ensured microbiological safety for 15 days at 4 ± 2 °C while minimizing the degradation of heat-sensitive compounds. These findings provide a scientific basis for the development of a bioactive-rich beverage from locally available plant materials. Phuong Linh Doan Thi Ngoc Thao Bui Thi Ngoc Mi Huynh Xuan Hong Nguyen Thi Hong Xuyen Nguyen Copyright (c) 2026 Dong Thap University Journal of Science https://creativecommons.org/licenses/by-nc/4.0 1 14 https://dthujs.vn/index.php/nsen/article/view/3243 Electrical conductivity in graphene–polymer composites varies over many orders of magnitude because conductive pathways form only when graphene flakes become sufficiently connected. This study analyzes a literature-derived dataset of 486 graphene–polymer composite samples using Random Forest and Gradient Boosting models. The input descriptors were polymer matrix, filler type, processing route, system classification, and graphene loading. The conductivity target was expressed as log10 (s) to reduce its wide dynamic range. On the fixed test split, Gradient Boosting achieved the best performance, with R2=0.91, RMSE=1.36, and MAE=0.93 in log10 (s) space, compared with R2=0.84, RMSE=1.77 and MAE=1.45 for Random Forest. The results indicate that graphene loading alone does not explain conductivity variation across heterogeneous systems. Grouped feature-importance analysis showed that graphene loading (34.1%), system classification (32.6%), and processing route (20.8%) had the largest relative contributions to the model predictions, whereas polymer matrix (9.1%) and filler type (3.2%) showed lower grouped importance. These percentages represent model-based relative importance rather than causal physical contributions. Microstructural descriptors, including graphene aspect ratio, dispersion quality, and agglomeration state, were not consistently reported in the source literature and therefore, they were not included among the five model inputs; their absence remains an important source of predictive uncertainty. Overall, interpretable machine learning provides a useful framework for analysing conductivity trends in literature-derived datasets while making explicit the limitations of the available data. TS Khả Quang Quách TS Thi Ngoc Tu Le Thi Bach Yen Truong Thi Thanh Thu Tran Copyright (c) 2026 Dong Thap University Journal of Science https://creativecommons.org/licenses/by-nc/4.0 1 16