http://tvhdh.vnio.org.vn:8080/dspace/handle/123456789/19538 2026-09-16T05:51:09Z http://tvhdh.vnio.org.vn:8080/dspace/handle/123456789/21847 Title: The first report on the marine snail Phos senticosus (Linnaeus, 1758) causing a tetrodotoxin poisoning in Viet Nam Authors: Dao, Viet Ha; Le, Ho Khanh Hy; Pham, Xuan Ky; Nguyen, Phuong Anh; Phan, Bao Vy; Doan, Thi Thiet; Phan, Minh Thu; Nguyen, Ngoc Tung Abstract: Tetrodotoxin (TTX) and two of its derivatives were detected in two horseshoe crab specimens that were leftover poisonous food in Vietnam using hydrophilic interaction liquid chromatography linked to tandem mass spectrometry (HILICMS/MS) analysis. According to the results, TTX accounted for almost 90% of the total toxicity in both specimens (4.2 and 30.3 g g−1). This was followed by 4,9- anhydroTTX (anh-TTX) (2.8 and 17.1 g g−1) and 4-epimerTTX (4-TTX) (1.9 and 11.4 g g−1). By the phylogenetic analysis based on COXI, two specimens were subsequently identified to be Carcinoscopius rotundicauda, a horseshoe crab that is known to be found across Vietnam and occasionally regarded as local seafood in coastal regions. Together with its strong lethal potency, it was suggested that TTX was the source of food poisoning in Vietnam brought on by the consumption of C. rotundicauda. At 146.2 MU g−1, specimen 2′s toxicity was almost seven times greater than specimen 1′s (20.3 MU g−1). The fact that poisoning symptoms were only observed in those who consumed specimen 2 could be explained by individual differences in TTX toxicity in this horseshoe crab species. To the best of our knowledge, TTX caused by eating horseshoe crabs was originally reported in Vietnam. According to the study, TTX in horseshoe crabs poses a threat to seafood safety in Vietnam. 2025-01-01T00:00:00Z http://tvhdh.vnio.org.vn:8080/dspace/handle/123456789/21840 Title: Biodiversity of Tintinnids (Tintinnida) in Khanh Hoa - Binh Thuan waters. Authors: Nguyen, Thi Kieu; Phan, Tan Luom; Nguyen, Tam Vinh; Nguyen, Ngoc Lam; Joseph, P. Montoya; Doan, Nhu Hai Abstract: Tintinnidsarean important protozoan group in the aquatic food web and had been widely studied in various waters. There are about 1000 known species in the world. However, there have beenvery few taxonomic studies in Vietnam and therefore the number of Tintinnid taxa and their distribution are poorly known. Thepresent study documents 65 tintinnids species belonging to 30 genera and 13 families in samples collected from Khanh Hoa - Binh Thuan waters in 2016 and 2017. There were 17 new taxa records for Vietnam protozoan fauna, raising the number of tintinnids recorded in Vietnam to 125 taxa. Tintinnid assemblages in Khanh Hoa-Binh Thuan waters shared about 17 species with Ha Long Bay, 32 species with Con Co island and 26 species with coastal waters of South Vietnam. Analysis of species diversity shows that the Shannon diversity index H' varied from 1.5 to 2.6. Distribution of species numbers and diversity in the Khanh Hoa - Binh Thuan waters revealed possible combined effects of hydrographical activities (e.g. upwelling), Mekong river influent (e.g. salinity), and food available on tintinnid communities. 2017-01-01T00:00:00Z http://tvhdh.vnio.org.vn:8080/dspace/handle/123456789/21832 Title: Evaluation of bioactivities and formulation of face mask from Sargassum sp. extract. Authors: Dang, Diem Hong; Phan, Bao Vy; Ngo, Thi Hoai Thu; Tran, Xuan Khoi; Nguyen, Cam Ha; Luu, Thi Tam Abstract: Brown seaweeds, particularly Sargassum genus, contain large amount of polysaccharides, such as alginate and fucoidan, which are widely applied to related health care approaches. Obviously, this genus is a potential alternative resource for cosmetic industry with its extract gained a great deal of biochemical composition and bioactivity. This study showed that the protein, lipid, total carbohydrate, chlorophyll and carotenoid contents of Sargassum sp. which collected in Khanh Hoa, Vietnam were 10.45 ± 1.15%, 1.90 ± 0.12%, 50.55 ± 1.05%, 0.25 ± 0.03 mg/g and 0.104 ± 0.001 mg/g of dry weight (DW), respectively. The hot water extract of Sargassum sp. showed high free radical scavenging activity (85.82 ± 1.89% at 50 mg/mL), antibacterial activity with the range of minimal inhibitory concentrations (MIC) from 25–100 mg/mL and tyrosinase inhibitory activity (16.19 ± 1.05%, 22.94 ± 1.23%, 104.16 ± 4.15% at concentrations of 50, 100 and 200 mg/mL). The formula of face mask from 10% of Sargassum sp. extract gained antioxidant and tyrosinase inhibitory activity with 61.67 ± 0.06% and 29.064 ± 0.06%, respectively. This product was also evaluated for the physical properties included organoleptic (brown color with specific odor), pH, homogeneity, spread ability and irritation test. The bacterial criteria, heavy metal levels of face mask were also recognized to evaluate for safety of human health following Ministry of Health standard. 2018-01-01T00:00:00Z http://tvhdh.vnio.org.vn:8080/dspace/handle/123456789/21820 Title: Effect of temperature and light intensity on the growth of Eucheuma denticulatum seaweed branches from Van Phong Bay under laboratory conditions. Authors: Vu, Thi Mo; Le, Trong Nghia; Tran, Mai Duc; Le, Truong Trung Lien; Ho, Son Lam; Anuraj, Anirudhan Abstract: Establishing an initial source of tissue culture material is the first and most important step in the propagation process. To prepare for this stage, seaweed must be acclimatized in vitro for 4 to 8 weeks before sterilization. In this study, Eucheuma denticulatum seaweed branches were collected from seaweed farms operated by local households in Van Phong Bay, Dai Lanh commune, Khanh Hoa province, brought to the laboratory, and acclimatized in a controlled environment. Healthy branches with a glossy brown color were carefully selected, cut into 10–15 cm lengths, and fresh-weight 13–15 grams samples were tied to mesh frames and placed in glass tanks measuring 35 × 40 × 60 cm. Environmental factors such as temperature (22–30oC) and light intensity (40–200 µmol photons·m-2·s-1) were tested. The results showed that after six weeks of acclimation, E. denticulatum branches thrived best at 26oC, achieving a high survival rate of 73.33%, a fresh weight of 21.38 g, the highest cumulative growth rate of 1.12 %·day-1, and the lowest ice-ice disease prevalence at 1.11%. Similarly, after six weeks of acclimation, the branches showed optimal growth under specific light intensity conditions of 120 µmol photon·m-2·s-1, with a high survival rate of 77.78%, a fresh weight of 28.82 g, the highest cumulative growth rate of 1.77 %·day-1, and no occurrence of ice-ice disease. The E. denticulatum branches cultivated under optimal conditions are poised to serve as ideal raw materials for propagation through tissue culture techniques, paving the way for efficient production and the replacement of natural seaweed stocks. 2026-01-01T00:00:00Z http://tvhdh.vnio.org.vn:8080/dspace/handle/123456789/21819 Title: Intercomparison of statistical and machine-learning methods for sea-level trend estimation at the Hon Dau tide gauge (1960–2024). Authors: Vu, Duy Vinh; Sylvain, Ouillon; Dao, Dinh Cham; Nguyen, Thi Thu; Nguyen, Minh Hai; Trinh, Hoai Thu Abstract: This paper presents an intercomparison of statistical, machine-learning, and signal decomposition methods for estimating sea-level trends using the long-term tide-gauge record at Hon Dau tide gauge (northern Vietnam) during 1960–2024. Classical statistical approaches (Mann–Kendall, Ordinary Least Squares), machine-learning models (Random Forest, Support Vector Regression, Artificial Neural Network, Long Short-Term Memory), and signal decomposition techniques (Empirical Mode Decomposition, and Complete Ensemble Empirical Mode Decomposition with Adaptive Noise) were employed to assess linear, nonlinear, and multi-scale sea-level variations. The results indicate a stable diurnal tidal regime with pronounced seasonal modulation, with lowest water levels occurring in March (182.1 cm) and highest levels in October (208.9 cm). All methods consistently detect a statistically significant long-term rise in mean sea level of approximately 3.7–3.9 mm.yr⁻¹ (equivalent to about 25–27 cm over six decades). A higher rate of sea-level rise, on the order of 7–9 mm.yr⁻¹, is identified for the more recent period 2005–2024. Machine-learning and decomposition-based approaches provide complementary insights into nonlinear behavior and multi-scale oscillations associated with ENSO and monsoon variability, while classical statistical methods offer transparent baseline estimates of long-term change. Seasonal analyses further reveal stronger and more stable increases during the dry season and weaker, more variable trends during the wet monsoon. Overall, the consistency of trend estimates across multiple methods highlights the robustness of the observed sea-level rise and underscores the value of a multi-method framework for sea-level monitoring and climate adaptation studies in Vietnam. 2026-01-01T00:00:00Z