CTU Journal of Science

Khung điểm Tạp chí Khoa học Đại học Cần Thơ năm 2025

Ngày 11/7/2025, Hội đồng Giáo sư Nhà nước đã ban hành Quyết định số 26/QĐ-HĐGSNN phê duyệt danh mục tạp chí khoa học được tính điểm của 28 Hội đồng Giáo sư ngành, liên ngành năm 2025. Theo đó, Tạp chí Khoa học Đại học Cần Thơ (https://ctujsvn.ctu.edu.vn/) được phê duyệt trong danh mục tạp chí khoa học được tính điểm của 20 Hội đồng Giáo sư ngành, liên ngành năm 2025. Trong đó, Tạp chí được 1 Hội đồng công nhận mới và 2 Hội đồng nâng điểm.

Brain tumor mri segmentation using an improved Res-UNet algorithm

Quy LaHoang, Dinh PhamToan*
Abstract | PDF (Tiếng Việt)
This paper presents a Res-UNet-based deep learning architecture that incorporates residual learning, an attention mechanism, and dilated convolutions to improve boundary preservation and feature representation in medical images. The model was trained and evaluated using an MRI dataset containing 3,929 images. Experimental results indicate that the proposed approach provides better segmentation performance compared with several existing methods, including traditional U-Net, Fuzzy C-Means (FCM), Attention U-Net, UNet++, SegNet, Swin-UNet, TransUNet, and nnUNet. The model achieved BF = 98.0%, SSIM = 99.2%, ACC = 99.7%, Dice coefficient = 86.6%, and IoU = 76.6%. Furthermore, tumor presence classification based on the generated segmentation labels reached an accuracy of 99.7% on the test set. These findings suggest that the proposed architecture is a promising approach for medical image analysis.

Pearson’s Chi-squared test for logistic regression model with covariates missing at random and application to the Titanic dataset

Ngo Thao Uyen, Duong Thi Tuyen, Tran Phuoc Loc*
Abstract | PDF (Tiếng Việt)
This study proposes a Pearson’s Chi-square (PCS) goodness-of-fit (GOF) test for a logistic regression model with covariates missing at random. A weighted test statistic (W-Pearson) is developed based on semiparametric inverse probability weighting (SIPW) to correct for bias induced by missing data and to provide a more reliable assessment of model adequacy compared to the complete case (CC) approach. Theoretical results show that the standardized test statistic is asymptotically normal. Simulation studies demonstrate that the W-Pearson test effectively controls type I error and achieves higher power than the C-Pearson test, particularly under high missing rates or model misspecification, while approaching the performance of the full-data Pearson test when no missingness is present. An application to the Titanic dataset indicates that the SIPW method improves estimation efficiency and model fit.

In vitro propagation of Clinacanthus nutans (Burm. f.) Lindau

Nguyen Van Ay, TRan Nguyen Phuong Nguyen, Le Thi My Hanh, Tran Ngoc Quy*
Abstract | PDF (Tiếng Việt)
The study was conducted to develop an efficient propagation protocol for the conservation and development of this valuable medicinal plant. The study consisted of three main objectives: evaluating the effect of Benzyl adenine BA on shoot induction, assessing the influence of α-Naphthalene acetic acid (NAA) combined with activated charcoal on root formation, and determining suitable substrates for ex vitro plantlets. Results indicated that MS medium supplemented with 0.5 - 0.75 mg/L BA combined with 0.05 mg/L NAA produced the highest shoot multiplication rate, with 3.78 - 4.00 shoots per explant after 8 weeks of culture. For rooting, MS medium supplemented with 0.5 mg/L NAA and 0 - 2 g/L activated charcoal achieved 100% rooting after 4 weeks. Acclimatized plantlets grown under greenhouse conditions exhibited a 93.33% survival rate, vigorous growth, and good adaptation. Hypothetically, one original explant can produce 5.200 - 7.600 plantlets within one year.

Morphological, anatomical and chemical composition of Sesuvium portulacastrum (L.) L. in selected coastal areas of Ca Mau

Phung Thi Hang*, Nguyen Thi Huyen Tran, Chung Thi Anh Linh, Nguyen Thi Tuyet Hue, Tran Ngoc Han, Le Phuoc Lam, Nguyen Nguyen Tran, Nguyen Vo Chau Ngan
Abstract | PDF (Tiếng Việt)
This study aimed to investigate the morphological, anatomical, and phytochemical characteristics of Sesuvium portulacastrum (L.) L. collected from several coastal sites in Ca Mau Province, Vietnam. Plant samples were collected from five sampling sites and evaluated using morphological, plant anatomical, powdered crude drug microscopic, and qualitative phytochemical analyses. The results revealed that S. portulacastrum possesses several adaptive characteristics to coastal environments, including succulent stems and leaves, a well-developed cuticle, abundant water-storage parenchyma, and a well-developed vascular system. Powder microscopy identified characteristic microscopic features, including starch grains, calcium oxalate crystals, stomata, and various types of vascular elements. Qualitative phytochemical screening confirmed the presence of several bioactive compounds, including flavonoids, phenolic compounds, tannins, coumarins, essential oils, and diterpenes. These findings provide valuable scientific data to support the sustainable utilization, conservation, and development of S. portulacastrum in the coastal regions of Vietnam.

Effects of Nutritional and Culture Conditions on Phosphate Solubilization by Enterobacter hormaechei GC1.3 Isolated from the Rhizosphere Soil of Wild Rice in Go Cong, Dong Thap Province

Nguyen Thi Hong Xuyen, Ton Nu Thanh Nhan, Phan Ngoc Nhu, Le Thi Tuyet Cam, Huynh Thi Nhu Huynh, Nguyen Thi Tuyet Nhung, Ky Thien, Do Tan Khang, Tran Thi Giang*
Abstract | PDF (Tiếng Việt)
This study evaluated the effects of nutritional and environmental culture conditions on the phosphate-solubilizing ability of Enterobacter hormaechei GC1.3 isolated from the rhizosphere soil of wild rice in Go Cong, Dong Thap Province, Vietnam. The strain was cultivated in NBRIP medium, and the effects of inorganic phosphate concentration, carbon sources, nitrogen sources, carbon-nitrogen combinations, insoluble phosphate forms (FePO₄ and AlPO₄), temperature, and cultivation conditions were investigated. The results showed that strain GC1.3 exhibited the highest phosphate-solubilizing activity in a medium containing 5 g/L Ca₃(PO₄)₂, 10 g/L glucose, and 0.1 g/L (NH₄)₂SO₄. The combination of glucose and (NH₄)₂SO₄ was identified as the optimal condition, yielding a maximum soluble phosphate concentration of 800.07 mg/L. The strain solubilized FePO₄ more effectively than AlPO₄, with the highest soluble phosphate concentration reaching 142.96 mg/L. Shaking cultivation at 25-30°C resulted in the greatest phosphate-solubilizing efficiency. These findings demonstrate the potential of E. hormaechei GC1.3 as a microbial inoculant for enhancing phosphorus availability and uptake in rice cultivation, reducing chemical fertilizer inputs, and supporting sustainable agricultural production.

Genetic diversity of Bagrid catfishes belonging to the Bagridae based on ISSR markers

Nguyen Tuyet Nga, Nguyen Pham Anh Thi, Nguyen Thi Pha*
Abstract | PDF (Tiếng Việt)
In recent years, natural catfish resources have shown a declining trend due to overexploitation and water pollution. The reduction in population size may affect the genetic diversity of these species. This study aimed to assess the genetic diversity of catfish species using ISSR (Inter-Simple Sequence Repeat) molecular markers. A total of 30 catfish samples were used in the study, collected from three provinces: An Giang, Can Tho, and Tay Ninh. Of the 14 primers evaluated, 6 primers were selected for the amplification of polymorphic DNA fragments. These primers generated a total of 104 bands ranging in size from 105 bp to 1750 bp, with PIC values ranging from 0.26 to 0.57. The UPGMA cluster analysis revealed that the catfish samples exhibited relatively high genetic similarity coefficients, ranging from 70% to 94%.

The double profit model: The law of large numbers and higher-order moments

Trinh Huu Nghiem*, Lam Hoang Chuong
Abstract | PDF (Tiếng Việt)
This paper investigates the asymptotic properties of the “double profit” model in probability theory under a generalized winning probability . Building upon the previously established Central Limit Theorem at the critical threshold , this study extends the analysis to establish the Law of Large Numbers for the case where  Crucially, the core scientific contribution of this work lies in explicitly determining and proving the limiting behavior of the sequence of higher-order moments of the return process given a sufficiently large number of trades. These findings complement and complete the quantitative description of the statistical fluctuations and dynamical structures inherent in the generalized double profit model.

Screening of vehicle systems for topical delivery of anthraquinones using Hansen solubility parameters and finite-dose skin permeation modeling

Vo Thanh Khang, Duong Nhut Phong, Nguyen Trong Tuan, Trieu Phu Hau, Nguyen Quoc Chau Thanh*
Abstract | PDF (Tiếng Việt)
A combined in silico approach using skin permeation simulation, Hansen solubility parameters, and Pareto optimization was used to screen excipient systems for topical anthraquinone formulations. Simulation results revealed five compounds, including rubiadin (highest permeation), morindone (earliest absorption onset), nordamnacanthal and damnacanthal (deeper viable-skin distribution), while lucidin showed the poorest transdermal permeation but the strongest stratum corneum retention. Among 7.200 excipient systems, poly(ethylene glycol)/poly(ethylene oxide): castor oil: dimethyl sulfoxide (60:20:20, w/w/w) exhibited optimal skin coMPatibility, while urea: benzyl benzoate: propylene carbonate (50:30:20, w/w/w) showed the highest coMPatibility with anthraquinones. Pareto analysis further identified poly(1-vinyl-2-pyrrolidone):benzyl benzoate:propylene carbonate (50:30:20, w/w/w) as a skin-coMPatible balanced system for the active ingredient. These findings offer a rational preformulation-oriented basis for excipient screening in topical anthraquinone systems.

Application of Dirichlet mixture distribution for clustering solar radiation day types

Tran Van Ly*, Nguyen Thi Hong Dan, Truong Thanh An, Vuong Thi My Tien, Le Dai Nghiep
Abstract | PDF (Tiếng Việt)
The article investigates the applicability of a Dirichlet mixture distribution model combined with the Stochastic Approximation Expectation Maximization algorithm (mixD-SAEM) for clustering daily solar radiation patterns based on the distribution of the clearness index. The performance of the proposed approach is evaluated and compared with two widely used clustering methods, namely k-means and hierarchical clustering. Experiments are conducted on two datasets: a high-frequency solar radiation dataset previously used in the literature and solar radiation datasets collected from two meteorological stations in the Mekong Delta region of Vietnam, where only nine observations are available per day. For the sparse datasets, histograms used in the clustering process are constructed from probability density functions estimated by kernel density estimation. Clustering performance is assessed using the Silhouette and Davies–Bouldin indices. The results indicate that the mixD-SAEM approach is capable of effectively identifying distinct daily solar radiation patterns, particularly when the discriminative information is embedded in the distributional shape of the data.

Changes in quality of life and associated factors after community-based McKenzie exercise rehabilitation in patients with chronic low back pain

Le Nguyen Tri Nhan*, Phan Duc Bang, Vo Duy Nhan, Ngoq Van Tan, Le Trong Tai
Abstract | PDF (Tiếng Việt)
This study aimed to analyze changes in quality of life and associated factors after community-based rehabilitation using McKenzie exercises in patients with chronic low back pain. This was an uncontrolled clinical intervention study with longitudinal follow-up of 87 patients at three time points: baseline, 1 month, and 3 months after intervention. Quality of life was assessed using the EQ-5D-5L. Linear mixed-effects models were used for data analysis. Compared with baseline, the EQ-5D-5L score increased by an average of 0.047 points after 1 month and 0.211 points after 3 months (p < 0.001). In the final multivariable model, higher VAS scores were associated with lower EQ-5D-5L scores (β = -0.0292; p < 0.001), whereas exercise adherence was associated with higher EQ-5D-5L scores (β = 0.1181; p < 0.001). These findings suggest that pain monitoring and support for exercise adherence should be integrated into community-based rehabilitation for chronic low back pain.

Isolation of protease-producing bacteria from human facial skin

Ngo Thi Thu Ngan, Biết, Le Thi Yen Nhi, Nguyen Thi Thanh Thanh, Le Thi Cam Van, Nguyen Thi Huynh Nhu, Luu Phuc Loi, Le Uyen Thanh, Tam Huynh*
Abstract | PDF (Tiếng Việt)
This study aimed to isolate and screen protease-producing bacterial strains from the facial sebum of healthy humans. From 30 samples collected across the forehead, cheeks, and chin, a total of 260 bacterial strains were isolated. Proteolytic activity was evaluated on Casein agar and Skim milk agar plates over a 72-hour incubation period. The results revealed 21 strains capable of protein degradation, among which strain M7 exhibited the highest activity, achieving zone of clearance diameters of 40.67 mm on Casein agar and 37.33 mm on Skim milk agar. Among the protease-producing strains, 8 strains displayed lipase activity and 6 strains showed amylase activity. Molecular identification using 16S rDNA sequencing revealed that strain M7 belongs to the genus Bacillus and is phylogenetically closely related to Bacillus albus, Bacillus paramycoides, and members of the Bacillus cereus group. In conclusion, the study successfully selected strain M7 for its outstanding protease activity, demonstrating that the human facial microbiota represents a potential source for exploiting extracellular enzyme-producing bacteria.

Selection and identification of salt-tolerant phosphate-solubilizing fungal strains from the rhizosphere soil of wild rice (Oryza rufipogon)

Duong Hoang Yen Nhi, Cao Man Quan, Vo Thi Ngoc Tho, Nguyen Thi Pha, Do Tan Khang, Truong Thi Bich Van, Bui Thanh Liem, Nguyen Pham Anh Thi, Nguyen Chanh Tin, Tran Thi Giang*
Abstract | PDF (Tiếng Việt)
Phosphorus is an essential element involved in many physiological and biochemical processes in plants; however, most phosphorus in soil exists in insoluble forms. Thirty-one phosphate-solubilizing fungal strains were isolated on NBRIP medium from the rhizosphere soil of wild rice (Oryza rufipogon) in Can Tho City in this study. Qualitative evaluation of phosphate-solubilizing ability showed PSI values ranging from 1.04 to 1.93. Based on quantitative analysis of soluble phosphorus, fungal strain OM9.2 exhibited the highest phosphate-solubilizing capacity, reaching 1,041.36 mg/L on day 10. Molecular identification using the ITS region revealed that strain OM9.2 showed the highest similarity to the Talaromyces genus in the NCBI database. In addition, strain OM9.2 demonstrated salt tolerance up to 6‰ NaCl. Notably, at 2‰ NaCl, this strain achieved the highest phosphate solubilization, exceeding 1300 mg/L on day 15.

Optimization of extraction conditions for total polyphenol content and evaluation of antioxidant activity from Houttuynia cordata Thunb. leaves

Le Thi Bach*, Nguyen Nha Uyen, Tran Trung Hung, Pham Quoc Nhien, Pham Thi Kim Phuong
Abstract | PDF (Tiếng Việt)
Optimization of total polyphenol extraction from Houttuynia cordata Thunb. leaves was carried out using response surface methodology (RSM) based on a Box-Behnken design, followed by evaluation of the antioxidant activity of the obtained extract. The optimal extraction conditions were 89.66% ethanol, a solvent-to-material ratio of 53.50 mL/g, a temperature of 54.62ºC, and an extraction time of 4.39 h. The predicted total polyphenol content (TPC) was 119.807 mg GAE/g extract, while experimental validation yielded 118.373 ± 0.250 mg GAE/g extract. The optimized extract exhibited antioxidant activity, with IC50 values of 113.73 ± 0.37 µg/mL for the DPPH assay and 21.39 ± 0.11 µg/mL for the ABTS•+ assay. The close agreement between the predicted and experimental TPC values confirms the reliability of the optimization model and and supports its application for efficient polyphenol extraction from Houttuynia cordata leaves.

Investigation of antibacterial activity and effects on beneficial gut microbiota of breadfruit (Artocarpus altilis (Park.) Forb.) leaf extracts

Huynh Thanh Duy*, Tran Le Viet Ha, Nguyen Thi Hong Hieu, To Lu Cuong, Chung Thi My Duyen, Truong Minh Nhut, Le Kieu An, Tran Nguyen Minh Duy
Abstract | PDF (Tiếng Việt)
Breadfruit (Artocarpus altilis, Moraceae) has been reported to possess antibacterial properties and protective effects on the gastrointestinal mucosa. This study aimed to evaluate phytochemical composition, cytotoxicity, and antibacterial activity against gastrointestinal pathogens of 96% ethanol and aqueous extracts from yellow fallen breadfruit leaves. Phytochemical screening revealed the presence of alkaloids, flavonoids, coumarins, phenols, tannins, triterpenoids, and free sugars in both extracts. Neither extract exhibited significant cytotoxicity, maintaining L929 cell viability above 85% after 48 hours (MTT assay). Using the agar disk diffusion method, the ethanol extract showed moderate activity against Helicobacter pylori (inhibition zones ranged 20.1 – 27.3 mm), whereas the aqueous extract was inactive at the tested concentrations. Both extracts showed no inhibitory effects against Salmonella typhimurium and Vibrio parahaemolyticus, and did not affect beneficial bacteria (Bacillus clausii and Lactobacillus acidophilus). However, the MIC of the ethanol extract was 50 mg/mL for H. pylori and V. parahaemolyticus, and 100 mg/mL for S. typhimurium. These findings suggest potential for supporting H. pylori management and showed no detectable cytotoxicity under the experimental conditions.

Green synthesis of Zr-MOF-NH₂ in water at room temperature toward stable pesticide delivery for brown planthopper control in rice

Nguyen Duy, Le Thi Ngoc Yen, Nguyen Le Thien Ly, Nguyen Thi Tuyet Nhung*
Abstract | PDF (Tiếng Việt)
This study develops an amine-functionalized zirconium metal–organic framework Zr-MOF-NH2 synthesized via a green process in water at room temperature, eliminating toxic solvents and hydrothermal conditions. The material shows high crystallinity, thermal stability, and a Brunauer–Emmett–Teller (BET) surface area of ~ 945 m²/g with hierarchical porosity (micropores and mesopores). Thiamethoxam was used as a model pollutant, and a maximum adsorption capacity of approximately 103 mg/g was achieved at 30°C in aqueous medium with a contact time of 150 minutes. Kinetic analysis indicates a multi-step mechanism dominated by intra-particle diffusion, while equilibrium fits the Freundlich model (R² = 0,993), suggesting multilayer adsorption on a heterogeneous surface. The main interaction is hydrogen bonding between –NH2 groups and nitro groups. With eco-friendly synthesis and high water stability, Zr-MOF-NH2 is promising for sustainable pesticide management and reducing environmental pollution in rice cultivation.

Enzymatic characteristics, antibiotic resistance, and biofilm-forming ability of Aeromonas spp. isolated from common carp (Cyprinus sp.) in hatcheries

Vo Thu Huong, Huynh Anh, Tran Thi Ngoc Anh, Pham Yen Nhi, Huynh Ngoc Thanh Tam, Tran Huu Hau*
Abstract | PDF (Tiếng Việt)
Aeromonas bacteria are recognized as one of the most common pathogens affecting freshwater fish. This study was conducted to isolate Aeromonas strains and evaluate several virulence-related characteristics, including extracellular enzyme production, hemolytic activity, and antibiotic susceptibility. Five Aeromonas strains were identified. All isolates exhibited proteolytic and gelatinolytic activities and biofilm formation, while 4/5 strains showed lipolytic and hemolytic activities. The isolates were resistant to at least 4 of the 16 antibiotics tested; notably, CFH17db.2 showed the highest multidrug resistance, being resistant to 10/16 antibiotics (MAR = 0.63). Resistance was observed against two antibiotic classes, aminoglycosides and carbapenems. High resistance rates were recorded for imipenem, meropenem, amikacin, gentamicin, and piperacillin/tazobactam, whereas most isolates remained susceptible to cefepime, cefotaxime, ceftazidime, and tetracycline. The findings indicate that Aeromonas strains isolated from diseased carp possess multidrug resistance, posing a potential risk to aquaculture.

Investigation of polyphenol and flavonoid contents, antioxidant and α-glucosidase inhibitory potentials of Longi tea (Camellia longii Orel & Luu)

Huynh Thanh Duy, Nguyen Thanh Triet, Hoang Le Minh, Lam Tuan Kiet, Tran Le Trung Nhan, Tran Van Chen*
Abstract | PDF (Tiếng Việt)
Camellia longii, an endemic species of Vietnam, remains poorly investigated in terms of its biological potential. This study aimed to evaluate the total phenolic content (TPC), total flavonoid content (TFC), antioxidant activity, and α-glucosidase inhibitory activity of leaf and flower extracts of C. longii. The extracts exhibited high TPC values ranging from 324.89 ± 6.74 to 482.00 ± 8.82 mg GAE/g extract and TFC values ranging from 42.31 ± 0.68 to 48.07 ± 1.80 mg QE/g extract. The extracts exhibited strong antioxidant activity, with DPPH radical-scavenging IC50 values ranging from 13.20 ± 0.35 to 17.91 ± 0.22 µg/mL and ABTS radical-scavenging IC50 values ranging from 54.12 ± 0.77 to 60.80 ± 1.74 µg/mL. In addition, the extracts exhibited potent α-glucosidase inhibitory activity, with IC50 values ranging from 29.80 ± 0.15 to 37.99 ± 0.24 µg/mL. These findings provide the first scientific evidence supporting the potential of C. longii as a promising natural source for the development of antioxidant and blood glucose-regulating products.

Procedure for processing and recovering experimental data of specific heat zeolite with the support of a large language model

Tran Thai Bao, Le Thi Thuy My, Mai Ngoc Qui, Pham Thi Bich Thao*, Nguyen Thanh Tien
Abstract | PDF (Tiếng Việt)
Missing values and anomalous measurements are common in experimental materials datasets and can compromise both statistical reliability and the preservation of underlying physical relationships. While numerous data recovery methods have been developed, their ability to maintain the physical consistency of experimental data remains insufficiently explored. This study proposes a large-language-model-assisted workflow for processing zeolite heat-capacity data, in which the model supports data inspection, anomaly detection, code generation, and result visualization. These findings demonstrate that linear interpolation is more suitable for recovering zeolite heat-capacity data when both data completeness and physical consistency are required. Furthermore, the proposed workflow highlights the potential of large language models as effective research assistants for semi-automated processing, analysis, and visualization of experimental materials data while maintaining human oversight in scientific interpretation.

Genetic engineering in Yarrowia lipolytica for overproducing gamma-glutamylcysteine

Dang Bao Ngoc, Le Le Thi Be Ba, Chau Thi Thuy Hang, Do Thi Hoang Diem*
Abstract | PDF (Tiếng Việt)
This study aimed to engineer the yeast Yarrowia lipolytica for the enhanced accumulation of the dipeptide γ-glutamylcysteine (γ-GC). The research methodology involved the disruption of the ylGSH2 gene, which encodes glutathione synthetase, to block the second step of the glutathione (GSH) synthesis pathway. Subsequently, the ylGSH1 gene was overexpressed in either single or double copies under the control of the constitutive pTEF promoter. The successful synthesis of γ-GC instead of GSH in the resulting mutant strains (RIY455 & RIY445) was confirmed through advanced analytical techniques, including NMR spectroscopy & LC-QTOF/MS analysis. Results indicated that the engineered strains achieved intracellular thiol content of approximately 102 nmol/mg protein, while the presence of γ-GC was confirmed by NMR and LC-QTOF/MS analyses. Furthermore, supplementation with the precursors cysteine & glutamate significantly improved yields, reaching a maximum of 239.9 nmol/mg protein in strain RIY445, representing a 177% increase. The findings conclude that inactivation of the ylGSH2 gene, which encodes glutathione synthetase, together with overexpression of the ylGSH1 gene (one or two copies), resulted in increased accumulation of intracellular γ-glutamylcysteine (γ-GC). This research provides a promising biotechnological framework for the efficient production of γ-GC, a compound of significant medical & nutritional interest.

A preliminary assessment of the distribution status of the Rusa unicolor in U Minh Ha National park, Ca Mau province

Tran Quoc Khai*, Ngo Khang Duy, Huynh Kiet Anh Tuan, Nguyen Hoai Linh, Duong Van Nha, Ngo Minh Sang, Nguyen Tan Truyen
Abstract | PDF (Tiếng Việt)
A preliminary assessment of the distribution status of the Rusa unicolor in U Minh Ha National Park, Ca Mau Province, was conducted using three principal survey methods: targeted camera trapping, direct observation, and nocturnal spotlight surveys. The results confirmed the continued presence of R. unicolor within U Minh Ha National Park, with the population estimated to comprise up to 700 individuals, primarily distributed within the Strict Protection Zone. The data obtained from this study provide a scientific basis for monitoring population dynamics and formulating effective conservation measures for R. unicolor in U Minh Ha National Park in the future.

Synthesis, characterization, and evaluation of methylene blue removal efficiency from aqueous solution using a composite adsorbent derived from coffee-ground-based activated carbon

Phan Tuan Kiet, Huynh Huu Khang, Le Thanh Phu, Ngo Truong Ngoc Mai, Dang Huynh Giao, Luong Huynh Vu Thanh*
Abstract | PDF (Tiếng Việt)
A bio-derived composite adsorbent (ACPU) was synthesized from activated carbon derived from spent coffee grounds, chitosan, PVA, and UPE using glutaraldehyde as a crosslinker. Characterization confirmed Schiff base (C=N) formation and a mesoporous structure 18,207 Å, 16,521 m2/g with a rough surface. Maximum methylene blue adsorption reached 149.57 mg/g at pH 8 (40 mg/L). The adsorption process followed the pseudo-second-order kinetic model and the Freundlich and Dubinin–Radushkevich isotherm models, indicating multilayer physisorption. Thermodynamic results revealed a spontaneous and exothermic process, highlighting ACPU as an efficient, low-cost adsorbent for dye wastewater treatment.

Investigation of the chemical composition and biological activities of extract from Mansoa alliacea

Huynh Mai, Lam Thu, Pham Bang, Nguyen My, Le Sieu, Mai Trang, Nguyen Quyen, Do Tan Khang, Tran Thanh Men*
Abstract | PDF (Tiếng Việt)
Mansoa alliacea, a plant species belonging to the Bignoniaceae family, possesses promising medicinal potential due to its rich content of highly bioactive compounds. However, studies on this species in Vietnam remain limited. This study was conducted to qualitatively identify phytochemical constituents, quantify several bioactive compounds, and evaluate the biological activities of ethanol extracts from garlic vine leaves and stems. The phytochemical screening results revealed the presence of various bioactive compound groups, including alkaloids, flavonoids, saponins, coumarins, phenolics, and tannins. Among them, the stem extract exhibited a significantly higher flavonoid content (224,0±3,00 mg QE/g extract) compared to the leaf extract. Regarding biological activities, the leaf extract demonstrated stronger antioxidant activity in both ABTS and DPPH assays, as well as greater anti-inflammatory, UV-B protective, and antibacterial activities than the stem extract. However, the stem extract showed superior total antioxidant capacity, ferric reducing power, and α-amylase inhibitory activity.

Effects of different growing substrates on the growth, development and yield of vegetable corn (Zea mays L.)

Vo Thi Phuong*, Nguyen Phuoc Thanh, Pham Thi Thanh Mai, Le Thi Kim Ngan
Abstract | PDF (Tiếng Việt)
This study evaluated the effects of different growing substrates on the growth, development and yield of vegetable corn (Zea mays L.), to identify the most suitable components for cultivation. The experiment was arranged in a completely randomized design with five growing treatments, including topsoil (control), a mixture of composted cattle manure and topsoil, composted rice straw and topsoil, coconut coir and topsoil, and a mixture of all these components. The results indicated that growing components significantly affected the growth, development and yield of Zea mays L. A mixture of components consisting of 50% well-rotted cow manure and 50% loam soil supported significantly higher yields of plant growth, biomass accumulation, and productivity. The findings provide a scientific basis for selecting appropriate growing substrates and contribute to improving the efficiency and sustainability of Zea mays L. production through the utilization of locally available organic materials

Rainfall analysis and forecasting in Da Lat using statistical and hybrid deep learning models

Van Thi Huynh Nhu, Than Thi Huong Mai, On Bich Gia Han, Tran Phuoc Loc*
Abstract | PDF (Tiếng Việt)
This study used monthly average rainfall data from the Da Lat meteorological station for the period January 2002 to December 2024 to analyze and forecast rainfall variability. Ten missing observations (3.62%) were imputed using linear interpolation after assessing the missing-data mechanism. Seven forecasting models were evaluated, including four standalone models (Holt–Winters, SARIMA, Prophet, and LSTM) and three residual-based hybrid models (SARIMA+LSTM, HW+LSTM, and Prophet+LSTM). The LSTM component was enhanced through an ensemble strategy with two random seeds, the incorporation of sinusoidal seasonal features (sine/cosine), and a 24-month lookback window. The results showed that the Prophet+LSTM hybrid model achieved the lowest MAE (61.84 mm) among the models considered. In addition, the residuals satisfied the assumptions of white noise and approximate normality, indicating adequate model performance. Forecast results from research models provide a scientific basis for water-resource management and disaster-risk mitigation in the Lam Vien Plateau region.

Morphological characteristics of Psyttalia mangiferae Long & Oanh (Braconidae: Hymenoptera) and its parasitic infestation rate on the fruit fly host Bactrocera spp. (Diptera: Tephritidae) causing damage to Taiwan guava in My Tho commune, Dong Thap province

Nguyen Cam Dao, Nguyen Thi Oanh*
Abstract | PDF (Tiếng Việt)
Psyttalia mangiferae Long & Oanh has been recorded as a parasite of the fruit fly Bactrocera spp., causing damage to Taiwanese guava fruit in Dong Thap province. The wasp's body is bright yellow, except in males, where the base of abdominal segments 2, 3, and 4 are yellowish-brown. On the fruit fly host, females had an average length of 4.36 ± 0.29 mm, while males were 3.99 ± 0.58 mm. Parasitic wasps usually appeared about 7 - 10 days later than adult Bactrocera spp.. From January to July, the density of flies was high, averaging 98 - 131 individuals/1 kg of guava fruit, and the number of parasitic wasps peaked at the end of March, affecting 49.8% of the fruit. From August to October, the density of flies decreased to 26 - 64 flies per kilogram of guava fruit, a period when parasitic wasps were not commonly observed. Temperature generally did not affect the appearance of parasitic wasps, while rainfall did have some influence.

Synthesis and investigation of the photoluminescence properties of Mn⁴⁺, Na⁺ co–doped LaAlO₃ phosphors

Nguyen Minh Thuan, Nguyen Thi Thuy An, Le Tran Ngoc Tran, Truong Thi Bach Yen, Nguyen Thi Kim Chi*
Abstract | PDF (Tiếng Việt)
LaAlO₃ phosphors co–doped with Mn⁴⁺ and Na⁺ were synthesized via the co–precipitation method. X–ray diffraction analysis revealed that the crystallinity of the investigated LaAlO₃ materials improved with increasing calcination temperature up to 1.200°C. Photoluminescence spectra showed an emission band at 660–750 nm upon 410 nm excitation, corresponding to the characteristic red emission of Mn⁴⁺ ions. The optimal doping concentration was determined to be 0.3 mol% Mn⁴⁺ and 0.5 mol% Na⁺. The presence of Na⁺ ions in the LaAlO₃ host lattice acted as a charge compensator, contributing to structural stabilization and enhancing the luminescence intensity by 38% compared with the singly doped Mn⁴⁺ sample.

Antifungal activity of soybean (Glycine max (L.) MERRILL) rhizosphere Bacillus strains against Aspergillus flavus, Aspergillus tubingensis, and Fusarium falciforme

Nguyen Thi Lien*, Huynh Phuong Thuy Linh, Truong Le Trung Nhan, Nguyen Tang Phu
Abstract | PDF (Tiếng Việt)
Soybean (Glycine max L.) seed yield and quality are frequently reduced by fungal diseases. This study evaluated the antifungal activity of four bacterial strains, Bacillus velezensis AG8.2, Bacillus thuringiensis AG9.2, Bacillus siamensis AG11.2, and Bacillus subtilis AG16.2, against Aspergillus tubingensis, Aspergillus flavus, and Fusarium falciforme. In dual-culture assays, mycelial growth inhibition ranged from 6.15 to 54.3% for A. tubingensis, from 0 to 34.2% for A. flavus, and from 21.2 to 51.8% for F. falciforme. Cell-free supernatants of the tested strains inhibited both mycelial growth and spore germination, with stronger effects observed during the spore germination stage. In addition, volatile organic compounds produced by the bacterial strains exhibited considerable antifungal activity, with greater efficacy against F. falciforme than against the two Aspergillus species. These findings demonstrate the potential of the tested Bacillus strains for development as biocontrol agents for sustainable management of soybean fungal diseases.

The chemical composition and potential applications of two brown algae species, Padina boryana and Padina australis, in supporting the treatment of diabetes and cancer

Nguyen Duy Tuan, Nguyen Cuong Quoc, Le Dang Quang, Tran Duy Khang, Tran Thanh Men, Tran Quang De*
Abstract | PDF (Tiếng Việt)
The study aims to identify the chemical composition and evaluate some biological activities of two brown algae species, Padina boryana and Padina australis. GC–MS (gas chromatography–mass spectrometry) analysis detected 24 compounds in P. boryana and 20 compounds in P. australis. Among them, pentadecane is the main component of P. boryana with a content of 14.52%, while ethyl oleate is predominant in P. australis, accounting for 67.09%. The results of α-glucosidase enzyme inhibition tests showed that the petroleum ether (PE) fraction of P. australis exhibited the strongest activity, with an IC₅₀ of 0.175±0.008 µg/mL. Cytotoxic activity was also examined on two cancer cell lines, HepG2 (liver cancer) and MCF-7 (breast cancer). For P. boryana, the PE fraction had IC₅₀ values of 156.20±7.94 µg/mL on HepG2 and 163.56±5.03 µg/mL on MCF-7. The PE fraction of P. australis demonstrated a stronger effect, with IC₅₀ values of 111.02±5.54 and 60.73±1.54 µg/mL, respectively. The initial data provided serve as a basis for isolating and further studying bioactive compounds from these two species of algae.

Optimality conditions for fuzzy optimal control problems of several dependent variables via granular derivatives

Le Thanh Tung*, Tran Thien Khai, Pham Le Bach Ngoc, Trinh Tung
Abstract | PDF (Tiếng Việt)
In this paper, we investigate the necessary and sufficient optimality conditions for the fuzzy optimal control problem with several dependent variables via granular derivatives. By using the directional derivative approach, we first examine the necessary optimality condition. Then, the sufficient condition is established under convex assumptions. To emphasize the significance of the sufficient condition, which has received limited attention in previous fuzzy control optimization studies, a detailed example is provided. Finally, an application model for the fuzzy tracking problem is presented.

A density functional theory investigation of the adsorption of carbon monoxide on ruthenium-cobalt alloy

Dang Long Quan*, Nguyen Thanh Giang, Nguyen Thi My Lam, Le Hoang Anh Quoc Thao Nhi, Le Thi Hong Dao, Nguyen Hai Dang
Abstract | PDF (Tiếng Việt)
In this study, density functional theory was used to investigate the adsorption of carbon monoxide on the surface of a ruthenium-cobalt alloy. Samples were simulated using VESTA software. VASP was used to optimize the structure and calculate the energy. In addition, the adsorption distance and the electronic interaction between carbon monoxide and a substrate were determined. The results identified the optimal adsorption location for CO on the RuCo surface. This research contributes to completing the overall picture of CO adsorption on the surface of catalysts used for direct methanol fuel cells.

Painlevé–Kuratowski convergence conditions for efficient solution sets in a blood glucose regulation model

Nguyen Huy Hoang, Vo Thanh Tai*
Abstract | PDF (Tiếng Việt)
This paper investigates Painlevé–Kuratowski convergence conditions for efficient solution sets of a blood glucose regulation model formulated as a multiobjective optimal control problem. The aim is to clarify the stability of insulin control strategies under small perturbations of the model data. The method is based on the equimeasurability of the admissible control set, a growth condition for the right-hand side of the state equation, local integral convergence of the data, and generalized convexity properties of the integrand objective function. The main results establish compactness, arcwise connectedness and convergence properties of the feasible solution sets. These properties are then used to derive sufficient conditions under which the efficient solution sets of perturbed problems converge, in the Painlevé–Kuratowski sense, to the efficient solution set of the limiting problem. The obtained results provide a mathematical basis for stability analysis in blood glucose regulation models.

Isolation and screening of Bacillus sp. producing protease and evaluation of the effects of pH and temperature on enzyme activity

Dinh Dinh Ngoc Bich, Tran Tran Huu Hau, Huynh Ngoc Thanh Tam*
Abstract | PDF (Tiếng Việt)
This study aimed to isolate and screen protease-producing Bacillus spp. from bread-processing wastewater collected in Can Tho City and to evaluate the effects of temperature and pH on protease activity. A total of 18 bacterial isolates were obtained, of which 16 were identified as members of the genus Bacillus based on morphological and biochemical characteristics. All isolates exhibited proteolytic activity, with hydrolysis zone diameters ranging from 12.00 to 17.10 mm and protease activities of 0.21 – 0.55 U/mL. The highest protease activities were recorded in isolates StNK1.1 (0.55 U/mL) and StCR3.3 (0.52 U/mL). Temperature affected both protein hydrolysis and protease activity, with optimal values observed between 40 and 45°C. Isolate StCR3.3 exhibited the largest hydrolysis zone (23.50 mm) and the highest protease activity (1.45 U/mL) at 45°C. Protease activity remained high within the pH range of 6 – 8. Based on 16S rRNA gene sequence analysis, isolate StCR3.3 was identified as a member of the genus Bacillus, indicating its potential for protease production and the biological treatment of protein-rich wastewater.