Vietnam Journal of Science and Technology
Tạp chí của Bộ Khoa học và Công nghệ
Structure, aboveground biomass and biodiversity of selected natural forest states in the ecological restoration zone of the Hon Ba Natural Reserve
The ecological restoration zone of Hon Ba Nature Reserve covers approximately 9,553.5 hectares and comprises a variety of characteristic evergreen broadleaf forest states. A field survey was conducted using temporary standard plots (1,000 m2, 33.3x30.0 m) established in typical forest states of the study area to determine several forest characteristics, including forest structure, biomass, and biodiversity. The results indicated that the distribution of trees by diameter class (n/D1.3) and height class (n/Hvn) was similar among forest states, exhibiting a concentration in small diameter and height classes. Standing volume ranged from 36.7 to 221.7 m³/ha, while biomass ranged from 30.16 to 247.54 tonnes/ha. The total number of forest tree species observed in the forest states ranged from 12 to 36, of which 6 to 10 species had high ecological significance. The study area exhibited a notable decline in stand density, volume, species richness, and biodiversity index in comparison to general regional levels. This suggests that the study area has confronted considerable challenges pertaining to forest restoration and development, particularly with regard to the recovery rates of forest states distributed within the ecological restoration zone.
Hoàng Thanh Sơn, Lương Văn Dũng, Nguyễn Văn Tuấn
Sustainability evaluation of an integrated ecological system for dragon fruit cultivation using emergy accounting
This study aims to evaluate the sustainability of an integrated ecological system for dragon fruit cultivation by farming households. A closed ecological system based on material and energy circulation was proposed and implemented for dragon fruit farming households, utilising waste from dragon fruit biomass combined with livestock waste to generate valuable new products. In addition, emergy accounting analysis was applied for sustainability evaluation of an integrated ecological system. The results show that the emergy yield ratio (EYR) of the system is 0.99, indicating that no free environmental resource can be obtained for each unit of input invested in the integrated system. The emergy loading ratio (ELR) of the system is 0.35, which indicates a relatively low environmental loading, with renewable inputs outweighing non-renewable ones. Furthermore, the environmental sustainability index (EmSI) of the integrated system is 2.8, which is higher than that of conventional agricultural systems.
Thi Thien Kim Ho, Thanh Hung Nguyen, Thanh Hai Le, Thi Hieu Tran, Thi Phuong Thao Nguyen, Trung Kien Tran*
Development of an in vitro regeneration system for genetic transformation in peanut variety L27 (Arachis hypogaea L.)
Arachis hypogaea L. has high nutritional value for human health; however, its proteins are highly allergenic, and the levels of essential sulfur-containing amino acids are relatively low. Moreover, peanut yield and nutritional value are adversely affected by abiotic stresses, including drought, extreme temperatures, salinity, flooding, and elevated CO2 concentrations. This study aimed to develop an efficient regeneration system for Agrobacterium-mediated genetic transformation to enhance stress tolerance and improve seed quality in peanuts. The results indicated that the most effective seed sterilisation was achieved using 0.1% mercury(II) chloride (HgCl2) for a total of 9 minutes (5 minutes for the first treatment and 4 minutes for the second treatment). The optimal shoot tip regeneration was observed at 1.5 mg/l benzylaminopurine (BAP), while cotyledon axil explants showed the best response at 2.0 mg/l BAP. Multiple shoot induction from cotyledon axil explants was most successful with a combination of 2.0 mg/l BAP and 0.7 mg/l α-naphthaleneacetic acid (α-NAA), producing an average of 4.43 shoots per explant. In contrast, apical shoot tips did not induce multiple shoot formation. The highest rooting efficiency was achieved with 0.7 mg/l α-NAA, resulting in an average of 8.32 roots per shoot. Kanamycin selection was effective at 75 mg/l during shoot regeneration and 50 mg/l during rooting.
Effect of transplanting density and chemical fertiliser application rate on the growth and yield of Huong Thanh 10 rice variety in Thanh Hoa province
This study aimed to determine appropriate transplanting densities and chemical fertiliser rates for the Huong Thanh 10 rice variety in Thanh Hoa province. The experiment was conducted during the Spring and Summer crops of 2024 using a split-plot design with three replications. The main plot factor was the fertiliser rate per hectare with N:P2O5:K2O ratios. In the Spring crop, the treatments were P1: 80:70:60 kg/ha, P2: 90:80:70 kg/ha, P3: 100:90:80 kg/ha, and P4:110:100:90 kg/ha. In the Summer crop, the treatments were P1: 70:60:50 kg/ha, P2: 80:70:60 kg/ha, P3: 90:80:70 kg/ha, and P4: 100:90:80 kg/ha. The subplot factor was transplanting density: M1: 30 hills/m², M2: 40 hills/m², and M3: 50 hills/m². The results showed that growth duration, maximum number of tillers, number of filled grains per panicle, and 1,000-grain weight were the highest at a transplanting density of 30 hills/m² with fertiliser treatment P3. The highest actual yield was recorded in the M2P3 treatment, reaching 6.8 tonnes/ha in the Spring crop and 4.6 tonnes/ha in the Summer crop. This corresponded to a transplanting density of 40 hills/m² and fertiliser rates of 100 kg N + 90 kg P2O5 + 80 kg K2O per hectare in the Spring crop, and 90 kg N + 80 kg P2O5 + 70 kg K2O per hectare in the Summer crop.
Adherence to HIV pre-exposure prophylaxis among men who have sex with men in Thanh Hoa province
Objectives: To describe adherence to HIV pre-exposure prophylaxis among men who have sex with men (MSM) in Thanh Hoa province in 2024. Methods: A cross-sectional study was conducted among 374 men aged 16 years and older who had sex with men and were using HIV pre-exposure prophylaxis (PrEP) services from April 2024 to June 2024. Results showed that 21.2% of MSM had used PrEP for 12 months or longer. Among them, 87.2% of MSM used PrEP in combination with condom use during sexual intercourse; 2.9% of MSM reported forgetting to take their PrEP medication in the past month. Among those who missed doses, 81.8% forgot to take their medication for 1- 7 days, and 18.2% for more than 7 days. Common reminder methods included setting alarms (90.9%) and scheduling medication times (72.7%). When experiencing side effects, 91.4% of MSM reported them to PrEP clinic staff. Conclusions: Adherence-related practices still require strengthening in some areas. Therefore, communication interventions should be strengthened to ensure sustainable PrEP use among MSM.
Assess the effectiveness of the “Neonatal resuscitation” training programme at hospitals in Ha Nam province
This study aimed to evaluate the effectiveness of the “Neonatal resuscitation” training programme at hospitals in Ha Nam province (before the administrative merger), focusing on the improvement of healthcare professionals’ knowledge and practical skills and the reduction in neonatal morbidity and mortality rates. A before-and-after in terventional study was conducted on 317 neonates (≤30 days old) in critical condition who were treated at hospitals in Ha Nam province from June 2023 to June 2024. Additionally, 116 healthcare professionals (including doctors, nurses, and midwives) participated in the training programme and were assessed after training during the same period. After the training programme, the rates of neonatal deterioration and mortality decreased (from 2.3 to 0.9% and from 0.7 to 0.6%, respectively), along with a marked reduction in referrals to the National Children’s Hospital (from 16.9 to 8.2%). Although theoretical knowledge among healthcare professionals improved, further enhancement of practical skills is needed. The “Neonatal resuscitation” training programme proved effective in improving the quality of neonatal care in Ha Nam province. However, continued training programmes and regular supervision are essential to ensure sustainable improvement in healthcare professionals’ practical skills.
Thi Quynh Nga Nguyen, Thi Nga Phan, Thi Hoa Quach, Lan Huong Chu, Thi Huyen Trang Vuong, Thi Hong Le, Huy Phu Nguyen
Evaluation of cervical lymph node metastasis in tonsil cancer at Cho Ray Hospital (2019-2024)
Objective: To evaluate the rate of cervical lymph node metastasis in tonsil cancer at Cho Ray Hospital from 2019 to 2024. Subjects and methods: Patients who were diagnosed with tonsil cancer through pathological examination and treated at the Department of Otorhinolaryngology, Cho Ray Hospital, from June 2019 to June 2024 were included in the study. Results and discussion: The majority of patients were aged between 40 and 60 years (70.8%). The maleto-female ratio was 3.8/1. The most common functional symptom was pain at the tumour site (66.7%), followed by dysphagia and cervical lymphadenopathy, which accounted for 50.0 and 33.3%, respectively. Tumours were located on the right side in 54.2% of cases and on the left side in the remaining patients. The disease was associated with risk factors including alcohol consumption, smoking, and betel chewing. Pathological results indicated that squamous cell carcinoma of the tonsil was typically localised to one side. Regarding lymph node metastasis, our study showed that 70.8% of patients presented with cervical lymph node metastasis, whereas 29.2% had no metastatic lymph nodes. Conclusion: Tumours were predominantly staged as T1 and T2 (87.5%). The rate of lymph node metastasis was 40% in T1, 75% in T2, and 100% in T3, suggesting a greater incidence of metastasis in advanced stages.
Electrochemical detection of chloramphenicol residues in milk samples using a working electrode modified with Fe3O4 superparamagnetic nanoparticles
Antibiotic residues in food, particularly in agricultural and aquaculture products, have become a serious issue requiring effective solutions in Vietnam. This problem is largely attributed to the excessive use of antibiotics in livestock farming, which not only poses risks to public health but also negatively affects the reputation and commercial value of exported products. In this context, electrochemical sensors have been recognised as a potential technological solution due to their advantages, including simple fabrication, low analytical cost, quick response, and high sensitivity and selectivity. In this study, Fe3O4 superparamagnetic nanoparticles, characterised by high electron conductivity, low toxicity, good biocompatibility, and strong adsorption capacity for organic compounds such as antibiotics, were used to modify the working electrode of commercial C110 electrochemical sensors (Metrohm, Switzerland) in order to enhance the electrochemical signal and improve sensor sensitivity. The results showed that the electrochemical sensor detected chloramphenicol (CAP) in phosphate buffer solution (PBS) with a low limit of detection (LOD) of 0.06 μM, a relative standard deviation (RSD) of below 5%, and a recovery rate of 94.77%. The sensor was applied for the rapid determination of CAP residues in milk samples at a concentration of 1 μM, achieving recovery rates of 95-109% and a relative standard deviation of 2.14%. These promising findings serve as a foundation for further research to develop label-free, portable electrochemical sensors for on-site analysis, contributing to food safety monitoring and the protection of consumer health in Vietnam.
Van Dinh Tran, Van Khanh Nguyen, Truong An Nguyen,Doan Phuc Le, Thi Minh Hong Nguyen*
Preparation of a hydroxyapatite-supported titanium oxide via the hydrothermal method for photocatalytic degradation of textile dyes
In this study, the HAP-based adsorbent and photocatalytic materials, including hydroxyapatite synthesised from Ca(NO3)2 and NH4H2PO4 precursors and titanium oxide-immobilised HAP (TiO2/HAP) derived from TiCl3, were produced using a hydrothermal method. The obtained materials were characterised by several techniques: X-ray diffraction, scanning electron microscopy coupled with energy dispersive X-ray analysis (SEM/EDX), and surface charge determination via zeta potential measurements. The adsorption and photocatalytic performances of the materials were evaluated through degradation experiments of methylene blue (MB), alizarin yellow G (AYG), and indigo dye (XHT - textile dye collected from household-scale traditional weaving villages), with dye concentrations before and after treatment determined by UV-Vis spectrophotometry. Characterisation results indicated that titanium oxide was successfully immobilised and uniformly dispersed within the HAP matrix, and the particles exhibited good stability in the dispersion medium. The TiO2/HAP composite exhibited photocatalytic oxidation and degradation efficiencies exceeding 90% for all tested dyes after three hours of UV irradiation. This highlights the potential application of TiO2/HAP composite materials in the photocatalytic treatment of dye pollutants.
Hoang Minh Luong, Thi Hang Pham, Xuan Hoan Nguyen*
Synthesis and characterisation of PbO2-SnO2 composite on a stainless steel substrate
A PbO2-SnO2 composite was successfully synthesised by cyclic voltammetry (CV) on stainless steel (SS) substrate in an electrolyte containing 0.5 M Pb(NO3)2, 0.1 M HNO3, 0.05 M Cu(NO3)2, 0.1 M C2H6O2, and SnO2 with concentrations ranging from 500 to 2500 mg/l. This composite exhibited the best electrochemical properties when the SnO2 concentration in the solution was 1500 mg/l. The surface morphology and elemental composition of the composite were determined by scanning electron microscopy (SEM), X-ray diffraction (XRD), and energy-dispersive X-ray spectroscopy (EDX). The electrochemical properties of the SS/PbO2-SnO2 electrode were investigated in 0.5 M H2SO4 using CV and potentiodynamic polarisation I-E methods. The obtained SS/PbO2-SnO2 composite electrode was used as an anode for the electrochemical removal of methyl orange (MO) from aqueous solution under suitable conditions with different treatment times. The removal efficiency of MO was high, exceeding 90% after 30 minutes of treatment. The kinetics of MO removal followed a first-order reaction model with a linearity of R2=0.9736.
Research on the in vitro propagation of Dendrobium moschatum Buch.-Ham. ex Sw.
To determine the optimal culture conditions for the in vitro propagation of Dendrobium moschatum Buch.-Ham. ex Sw., a rare orchid species facing a high risk of extinction, the study evaluated the effects of plant growth regulators (GA3, BAP, TDZ, NAA) and activated charcoal on key developmental stages, including seed germination, shoot regeneration, and root induction prior to plantlet formation. All experiments were conducted under laboratory conditions. The results showed that Murashige & Skoog (MS) medium, supplemented with 3% sucrose and 5 g/l agar and adjusted to pH 5.8±0.1, produced the highest germination rate (89.67%). During the shoot regeneration stage, 3.0 mg/l BAP significantly promoted shoot formation, producing 4.25 shoots per explant. During the rooting stage, medium supplemented with 0.2 mg/l NAA and 2.0 g/l activated charcoal resulted in the highest rooting efficiency. The findings contribute to the optimisation of the in vitro propagation protocol for Dendrobium moschatum and support the conservation and development of this valuable orchid genetic resource.
Phuong Thu Pham2*, Thi Tuyet Nhung Nguyen, Thi Thu Hien Phan, Thi Thuong Vu
Quality control standards for stem cell culture and stem cell banking
Establishing quality control standards in stem cell culture facilities and stem cell banks plays a pivotal role in ensuring the safety, efficacy, and clinical applicability of stem cell-based therapies. This regulatory framework requires strict criteria, including cell origin, biological characteristics, purity, viability, differentiation potential, genomic stability, periodic quality assessments, and complete documentation for traceability. Stem cell culture facilities and stem cell banks must comply with Good Manufacturing Practice (GMP) and Good Tissue Practice (GTP) to minimise contamination risks and maintain optimal culture conditions. Additionally, biomedical ethics, donor screening procedures, and compliance with international regulatory standards (FDA, EMA) are essential for guaranteeing the quality of stem cell products. This article presents detailed quality control standards for stem cell culture and banking. Particular emphasis is placed on basic standards concerning facilities, cell authentication, cell counting and viability assessment, and microbiological safety evaluation.
Phuoc Vinh Nguyen, Thi Kim Ly Bui, Van Kien Vu
Effect of glycidyl methacrylate compatibiliser and montmorillonite reinforcement on the properties and morphology of PBAT/PLA blends
A polymer blend based on polybutylene adipate terephthalate and polylactic acid (PBAT/PLA) with enhanced mechanical properties was successfully fabricated by melt mixing in a twin-screw extruder using glycidyl methacrylate (GMA) as a compatibiliser and montmorillonite clay (MMT) as a reinforcement. The properties of the blend were characterised by a series of methods including ATR-FTIR spectroscopy, thermogravimetric analysis (TGA), scanning electron microscopy (SEM), and mechanical testing. The results showed that the PBAT/PLA blend with a weight ratio of 40/60 exhibited optimal mechanical properties. In addition, the GMA-based compatibiliser increased the compatibility of the PBAT/PLA blend through reactions between epoxy groups and the terminal COOH and OH groups of the polymer chains. The study also confirmed that the combined use of a GMA-based compatibiliser and clay improved the mechanical strength, thermal stability and structural stability of the materials. The PBAT/PLA/compatibiliser/clay blend with a mass ratio of 40/60/10/20 exhibited a tensile strength of 30.06 MPa, an elongation at break of 70.38%, and a tensile modulus of 1568 MPa. These results indicate significant potential for the production of environmentally friendly packaging and disposable food containers.
Thi Nguyet Anh Tuong*, Huong Thi Hoang, Hoang Linh Doan, Tien Dat Nguyen, Thi Thao Nghiem, Ngoc Diep Nguyen, Thao Yen Linh Dang, Van Huong Doan, Xuan Quang Chu
Effects of drying method on chemical composition and physicochemical properties of Spirulina platensis
The drying method affects the physical state, structure and chemical composition of Spirulina platensis, particularly its colour-related compounds exhibiting antioxidant activity. This study provides guidance on using drying methods to enhance the value chain of Spirulina. The results of the study demonstrated that the chemical composition and other physicochemical properties of Spirulina platensis were the least affected by freeze-drying at 30oC, followed by heat pump drying at 50oC, whereas hot-air drying at 50oC had the greatest impact. Within the scope of the study, hot-air-dried Spirulina platensis exhibited the highest peroxide value and the fastest sedimentation rate in water. Among the used methods in this study, freeze-drying is the most suitable method to retain secondary metabolites such as phycocyanin in Spirulina platensis. However, heat pump drying can be effectively used as an alternative to freeze-drying to reduce production costs while maintaining the application value of Spirulina platensis, provided that antioxidant activity is not the primary concern compared with colour or nutritional value.
Determination of methanol in gasoline using liquid-liquid extraction and gas chromatography-flame ionisation detector (GC-FID)
The concentration of methanol in gasoline was determined using liquid-liquid extraction and gas chromatographyflame ionisation detector (GC-FID). Methanol was transferred into the aqueous phase by liquid-liquid extraction before being separated on a Restek Rtx-Wax column and detected using a flame ionisation detector (FID). Gas chromatographic conditions, including column temperature programme, split ratio, and carrier gas flow rate, were investigated and selected to meet the requirement for methanol analysis. The methanol concentration in gasoline showed good linearity over the range of 3.96-7920 mg/l, with R²>0.99. The method detection limit (MDL) and method quantification limit (MQL) were 1.49 and 4.96 mg/l, respectively. The method precision, expressed as RSD, ranged from 1,49 to 4,96. The extraction recovery of methanol in gasoline ranged from 92.4 to 98.6%. The results indicated that the developed method meets accuracy requirements and is suitable for the determination of methanol in gasoline samples.
Thi Huong Thao Hoang*, Thi Phuong Thao Mai, Ngoc Hai Khuat
Chế tạo và nghiên cứu tính chất quang của vật liệu MgGa2O4 pha tạp Cr3+
Far-red light-emitting diodes (LEDs) have attracted increasing attention due to their positive effects on plant growth. When plants are exposed to far-red light, phytochrome far-red (PFR) absorbs the radiation and is converted into phytochrome red (PR), thereby stimulating plant growth. In this study, a far-red-emitting MgGa2O4:Cr³⁺ phosphor was synthesised using a thermal diffusion method. X-ray diffraction (XRD) analysis confirmed that at a calcination temperature of 1400°C, the material forms a single phase with good crystalline quality. Field-emission scanning electron microscopy (FESEM) images showed that the material possesses relatively large grains, ranging from 1 to 3 μm in size. Photoluminescence excitation (PLE) spectra revealed strong visible-light absorption, with two prominent peaks at approximately 415 and 574 nm. When excited at 415 nm, the material exhibited intense red emission, peaking at 707 nm, corresponding to the ²E→4A2 transition. Furthermore, an LED experiment using this material in combination with a 430 nm LED chip was successfully conducted. These findings indicate that Cr³⁺-doped MgGa2O4 is a promising candidate for far-red light-emitting LEDs in agricultural lighting applications.
Anh Tuyet Nguyen, Hong Dang Vu, Viet Hung Tran, Thi Hao Dung Duong, Mai Chi Ngo, Van Quang Nguyen*
Innovation of the pocket attachment sewing process through research, design, and fabrication of a semi-automatic jig-fixture-template system for the Juki AMS-221EN/2516 programmable sewing machine
Pocket facing attachment in veston/jacket production is commonly performed on single-needle sewing machines. During sewing, operators must manually fold and continuously hold the facing edge to ensure stitch-line accuracy, while retrieving and arranging semi-finished parts after sewing. These manual operations increase the sewing cycle time and lead to quality variation. This study proposes an innovative pocket-facing sewing process on the Juki AMS-221EN/2516 programmable sewing machine using a semi-automatic jig-fixture-template system. The system integrates a pneumatic edge-folding and clamping mechanism controlled by a PLC using a cycle-state control scheme synchronised with the sewing motion, and automatically retrieves and arranges semi-finished parts after sewing; consequently, interlocks are clearly managed and operational reliability is improved under repeated operation. Production trials were conducted 30 times over 30 days (4 hours per trial; n=30 for each method). Results show that the mean cycle time decreased from 11.9±0.7 s/part to 8.3±0.5 s/part (-30.3%; Welch’s t-test, p<0.001), corresponding to an output increase from 1212 to 1739 parts per 4 hours (+43.5%). The topstitch line became more stable and less dependent on operator skill due to the elimination of manual edge holding.
Xuan Hiep Hoang, Sy An Nguyen*, Van Lam Nguyen, Xuan Chu Do, Thi Hoan Duong
The impact of irrigation water quality on soil properties in vegetable-growing areas of Gia Lam, Hanoi
The research was conducted through pot experiments in a greenhouse combined with random sampling in the Cau Bay river irrigation area to compare soil characteristics before and after three experimental seasons using different types of water: treated domestic wastewater, Cau Bay river water, and well water supplemented with chemical fertilisers for several leafy vegetables grown on Red river alluvial soil in Gia Lam (Hanoi). The results showed that irrigation with wastewater and Cau Bay river water increased soil nitrogen (N), phosphorus (P), and organic matter contents. Soil pH, moisture, and nutrient levels were all improved compared with well water irrigation. However, with regular irrigation using Cau Bay river water, the accumulated N and P content in the soil was 1.4 to 1.5 times higher than with well water irrigation. This poses a potential risk of nitrate accumulation in soil and vegetables if nutrient balance among irrigation water, soil, and fertilisers is not adequately controlled.
Assessment of the penetration resistance of sand materials for aircraft protection fortifications
Constructing field fortifications using local materials to protect aircraft from sharp penetrating objects is a common practice when rapidly deploying protective structures at aircraft aprons. This approach offers several advantages of high flexibility, mobility, ease of construction, and cost-effectiveness compared to other aircraft protective structural solutions. This article focuses on numerical simulations using Abaqus to analyse the penetration capability of steel penetrators when coral sand from the East Sea of Vietnam and red sand from the Phan Thiet area are used as filling materials. The numerical simulation results indicate that coral sand from the offshore islands of Vietnam exhibits higher penetration resistance than Phan Thiet red sand, which has a smaller grain size modulus. The penetration depths of the penetrator in red sand and coral sand are 0.70 m and 0.495 m, respectively, corresponding to calculated penetration resistance coefficients (Kx) of 69.3.10-7 and 49.0.10-7, respectively. These findings provide an initial basis for the design and application of field fortification structures for aircraft protection using local materials.
Van Hieu Nguyen, Duy Khanh Duong*, Xuan Bang Nguyen
Research and design of a calibration and verification system for tape measures and rulers with a measurement range of up to 30 metres
To meet the demand for calibrating large-length measuring instruments, such as tape measures, rulers, and laser distance meters, in the construction, transportation, and industrial sectors, the research team has designed a calibration system with a measuring range of up to 30 metres using a laser interferometer derived from the primary length standard. Based on the research and analysis of standard systems currently in use at national metrology institutes around the world, the study proposes a system structure, operating principle, and design aligned with the technical, economic, and infrastructural conditions in Vietnam. Also, the system ensures feasibility, efficiency, and high applicability in practical use. The system includes a laser interferometer, a camera, mechanical components, and instruments for measuring environmental conditions and material temperature. This system ensures metrological traceability for large-length measuring instruments, including tape measures, line scales, and laser distance meters, while also meeting the growing practical demands of modern manufacturing and construction industries.
Xuan Dat Tran, Cong Dung Tong*, Xuan Dung Le, Nam Anh Tran, Khanh Phan Vu
Research and safety evaluation of the Bacillus subtilis Eramic 26 strain for application in probiotic production
This study evaluated the safety of the Bacillus subtilis Eramic 26 strain through assessments of antibacterial activity, hemolytic potential, cytotoxicity, and virulence/antibiotic resistance gene analysis, following the Generally Recognised As Safe (GRAS) guidelines of the U.S. Food and Drug Administration (FDA) and the European Food Safety Authority (EFSA). Antibacterial activity was tested against five indicator bacterial strains: Escherichia coli, Salmonella typhimurium, Enterococcus faecium, Staphylococcus aureus, and Shigella flexneri. Cytotoxicity was evaluated using two cell lines: human HT-29 and Vero. The results showed that B. subtilis Eramic 26 did not inhibit the tested bacterial strains and did not exhibit cytotoxic effects in either the HT-29 or Vero cell line. Genomic analysis revealed the presence of antibiotic resistance genes such as fosB, satA, and ydhE/norM, as well as mutations in gyrA and gyrB; however, all were located on the chromosome and not associated with mobile genetic elements. The strain harboured bacteriocin-encoding genes, including bacilysin and subtilosin, which enhance competitive fitness.Overall, the findings indicate that B. subtilis Eramic 26 is a safe bacterial strain with strong potential for applicationin probiotic production.
Thi Thuy Linh Doan, Gia Bach Dao, Thi Thuy Ngan Luu, Ba Binh Ngo
Gia Bach Dao, Thi Thanh Hoa Hoang, Thi Hoi Le*
Investigation of the chemical composition, antimicrobial and antioxidant activities of cashew nut testa extracts (Anacardium occidentale L.)
The cashew nut testa (Anacardium occidentale L.) is an agricultural byproduct with great potential, containing numerous natural compounds with significant biological activities. This study investigates the chemical composition, antimicrobial properties, and antioxidant capacity of the ethyl acetate extract derived from cashew nut testa. Qualitative analysis revealed the presence of compounds such as polyphenols, flavonoids, coumarins, and tannins, while alkaloids and saponins were not detected. The total polyphenol and catechin contents, along with their derivatives, were 566.50±0.76 mg GAE/g and 517.50 mg/g, respectively, with catechin (247.21 mg/g) being the predominant compound, followed by epigallocatechin gallate (166.27 mg/g) and epicatechin (94.49 mg/g). The extract exhibited strong antimicrobial activity, particularly against Staphylococcus aureus (21.00±0.50 mm) and Candida albicans (11.33±0.58 mm). Furthermore, the extract demonstrated remarkable antioxidant activity, with an IC50 value of 10.05±0.06 μg/ml, which was lower than that of vitamin C (11.62±0.18 μg/ml). These findings suggest that the ethyl acetate extract from cashew nut testa is a promising raw material with potential applications in pharmaceuticals and functional foods.
Thi Dung Nguyen, Van Toan Nguyen, Hai Son Pham, Le Kha Tu Bui, Thi Lieu Nguyen, Bao Thinh Bui*
Căn nguyên vi khuẩn trong dịch tỵ hầu ở bệnh nhân viêm phổi thùy tại Bệnh viện Nhi Trung ương từ tháng 3/2023 đến tháng 2/2024
Lobar pneumonia is a severe and rapid-onset pulmonary disease in children. Identifying bacterial pathogens by taking samples at the lesion site is challenging. This study aims to investigate bacterial pathogens in nasopharyngeal samples from children with lobar pneumonia, to determine co-infection rates and risk factors for typical bacterial coinfection caused by M. pneumoniae. The results showed that the positive rate in children was 555/835 (66.5%) using the multiplex real-time polymerase chain reaction (PCR) on nasopharyngeal samples, with Mycoplasma pneumoniae, Haemophilus influenzae, Streptococcus pneumoniae accounting for 32.1, 28.1, and 21.9%, respectively. However, the positive rate of nasopharyngeal culture was only 272/835 (32.6%), with H. influenzae (17.5%), M. catarrhalis (7.9%), and S. pneumoniae (7.4%). These findings suggest that multiplex real-time PCR has over 80% sensitivity and specificity compared to culture. M. pneumoniae was detected in 223/835 cases (26.7%), mainly in children aged 2-5 years. The rate of typical bacterial co-infection was 39/223 (17.5%). There was no difference between mono-infection and co-infection groups in children with lobar pneumonia caused by M. pneumoniae concerning demographic and clinical characteristics.
Thi Mai Nguyen*, Thanh Tu Tran, Thi Thuy Duong, Ngoc Van Nguyen, Thi Thu Hang Nguyen, Duc Anh Vu, Huy Khanh Nguyen
Prevalence of sarcopenia among outpatients with chronic obstructive pulmonary disease at Nghe An Lung Hospital in 2024
Objectives: This study aimed to determine the prevalence of sarcopenia among outpatients with chronic obstructive pulmonary disease (COPD) at Nghe An Lung Hospital in 2024. Subjects and methods: A cross-sectional descriptive study was conducted among 399 outpatients with COPD at Nghe An Lung Hospital in 2024. The skeletal muscle mass index (SMI) was measured using the Inbody 770 device. Sarcopenia was classified into four categories: normal, pre-sarcopenia, moderate sarcopenia, and severe sarcopenia, according to the 2019 diagnostic criteria of the Asian Working Group for Sarcopenia (AWGS). Results: The results showed that 38.1% of the study participants had normal SMI, while 52.1% were diagnosed with pre-sarcopenia. The overall prevalence of sarcopenia among the study population was 9.8%. Sarcopenia prevalence increased with the severity of airway obstruction. According to the Global Initiative for Chronic Obstructive Lung Disease (GOLD) classification, sarcopenia prevalence was 7.0% in stages 1-2 and 18.5% in stage 4. Group E patients had the highest prevalence (11.8%), while groups A and B showed a prevalence of 8.3%. Conclusions: The prevalence of sarcopenia was 9.8%. The prevalence was higher in females than males (10.5 and 9.6%, respectively; p>0.05). The prevalence was also higher in the group aged over 60 years than in those under 60 years (10.3 and 7.9%, respectively; p>0.05). In addition, the prevalence increased progressively with disease severity and the degree of airway obstruction (p<0.05).
Optimisation of infrared radiation-assisted heat pump drying for Pangasius krempfi
Pangasius krempfi is a high-value aquatic species; however, traditional drying methods such as sun drying and conventional kiln drying present several limitations, including extended drying time, inconsistent product quality, and limited process control. This study aimed to optimise the drying process of P. krempfi using a hybrid drying technology combining a heat pump and infrared radiation. The experimental design followed response surface methodology (RSM) with four independent variables: drying temperature (40-60°C), air velocity (1-3 m/s), material thickness (1-2 cm), and sorbitol concentration (5-25%). Evaluation criteria included drying time, rehydration rate, sensory score, and water activity. Experimental data were analysed using second-order regression and analysis of variance (ANOVA). The results indicate that drying temperature and sorbitol concentration had a significant impact on product quality parameters (p<0.01). The optimal conditions were determined as a drying temperature of 60°C, an air velocity of 1.4 m/s, a sample thickness of 1.0 cm, and a sorbitol concentration of 5%, yielding a drying time of 5.2 h, a rehydration rate of 63%, a sensory score of 18.34/20, and a water activity of 0.57. These findings contribute to strengthening the scientific basis for the adoption of combined drying technologies in the processing of P. krempfi and similar aquatic products.
Thai Ha Hoang*, Xuan Cuong Dang, Thanh Dat Le, Hoang Thai Doan, Duy Thuan Tran, Thuy Nga Nguyen, Dinh Toan Anh Tran
Synthesis of iron nanomaterials using Terminalia catappa L. leaf extract and their application in stimulating maize seed germination
Green chemistry-based synthesis of nanomaterials has emerged as a promising approach due to its environmental friendliness and high potential for sustainable agricultural applications. In this study, Terminalia catappa L. leaf extract was employed as a biological reducing agent to convert ferric ions (Fe3+) into metallic iron (Feo), thereby synthesising iron nanoparticles. The extract was obtained by ultrasonic-assisted extraction using 70% ethanol, with total polyphenol and flavonoid contents of 85.12±0.97 mg GAE/g DW and 104.6±8.72 mg QE/g DW, respectively. The effects of Fe3+ precursor concentration, reaction temperature, and reaction time on nanoparticle synthesis were investigated and optimised based on experiments evaluating the germination-stimulating effects on maize seeds. The structural and morphological characteristics of the synthesised material were analysed using XRD, FTIR, and SEM techniques. The results revealed a distinct diffraction peak of Feo at 2θ=45.7o, with particle sizes ranging from 20 to 100 nm and an average size of ∼80 nm. The green-synthesised iron nanoparticles exhibited a notable stimulatory effect on seed germination, suggesting their potential as a bioactive nanomaterial for stimulating plant growth.
Van Minh Dao, Thi Viet Quynh Nguyen, Thi Van Anh Phan*
Thi Hong Phuong Nguyen, Hoai Phuong Nguyen
Differences in the success rate of the surgical creation of vascular access for hemodialysis in patients with and without diabetes
The most preferred vascular access method for hemodialysis in patients with end-stage renal disease is the autologous arteriovenous fistula (AVF). However, a significant percentage of AVF fails to support dialysis therapy due to a lack of adequate maturity. Among all the factors, the presence of diabetes has been identified by some authors to be one of the risk factors for vascular access failure; however, some other authors found no such association. Therefore, this study aimed to evaluate the correlation between diabetes and the success rate of AVF. Among the 125 patients included in the study, 75 were female (60%), a total of 151 autologous arteriovenous fistulas were performed. Among the patients, 22 underwent surgery twice at two different sites (17.6%), and 2 patients underwent surgery three times at three different sites (1.6%). Early fistula occlusion and failure to mature occurred in 34 out of 151 cases (22.5%). Among these, 54 of 67 patients with diabetes (80.6%) and 63 of 84 patients without diabetes (75%) had successful fistula maturation and were able to undergo hemodialysis. The difference was not statistically significant. Diabetic vasculopathy, particularly in patients with end-stage chronic kidney disease, presents a number of specific problems, the most important of which appears to be arterial calcification and stiffening.
Tetrahydrocurcumin (THC) is 1.7-bis(4-hydroxy-3-methoxyphenyl)-heptane-3.5-dione with the empirical formula C21H24O6 and a molecular weight 372 g/mol, and is a bioactive beta-diketone compound. It can be isolated from turmeric (Curcuma longa L.) or semi-synthesised from curcumin. THC could inhibit lipid peroxidation in erythrocyte membranes induced by tert-butyl hydroperoxide, showing a greater effect than curcumin, as well as ameliorate oxidative stress-induced renal injury. In addition, THC possesses anti-inflammatory, antioxidant, and anti-aging activities. In this article, THC was semi-synthesised from curcumin using two methods. In the first approach, curcumin was acetylated with acetic anhydride in pyridine to afford curcumin acetyl (1) to form THC-acetyl (2) via the catalytic hydrogenation using 10% Pd/C in EtOH at room temperature, followed by deacetylation with NaOH 8% at pH 9 to yield THC (3). In the second method, catalytic hydrogenation in the presence of 10% Pd/C in solvent or EtOH/NaOH (solid), or EtOH/NH4OH 25% at room temperature to obtain THC (3) in good yields. The structures of the compounds were confirmed by nuclear magnetic resonance (NMR) and liquid chromatography-electrospray ionisation mass spectrometry (LC-ESI-MS).
Thanh Ha Tran, Thi Phuong Le, Hai Long Pham, Thi Ha Nguyen*
Study on antibacterial and anti-inflammatory activities of the total aqueous extract from Oxalis corniculata L.
Oxalis corniculata L. is a medicinal plant traditionally used for its antibacterial, anti-inflammatory, and wound-healing properties. However, studies on the pharmacological effects of O. corniculata L. remain limited in Vietnam. This study aimed to evaluate the antibacterial and anti-inflammatory activities of the total aqueous extract (TAE) from O. corniculata L.. The antibacterial activity was determined using the agar diffusion method against Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa. The anti-inflammatory activity was assessed in mice using the carrageenan-induced paw edema model. The results showed that TAE exhibited antibacterial activity against S. aureus (11 mm inhibition zone) at a concentration of 300 mg/ml but showed no significant activity against E. coli and P. aeruginosa. In the paw edema model, 1000 mg/kg of TAE reduced paw swelling comparable to ibuprofen (7.5 mg/kg) from day 1 to day 6, while 500 mg/kg showed similar effects on days 1, 2, and 4. These findings suggest the potential application of O. corniculata L. in pharmaceutical research and development.
Thi Be Nguyen, Thi Thanh Thao Dao, Van Vien Doan*
The relationship between depression, anxiety, stress, sleep disorders, and eating disorders among medical students at Thai Binh University of Medicine and Pharmacy
Objectives: To analyse the relationships between depression, anxiety, stress, sleep disorders, and eating disorders among first-year students at Thai Binh University of Medicine and Pharmacy in 2024 and 2025. Methods: A cross-sectional study was conducted among 394 students. The EAT-26, PSQI, and DASS-21 scales were used for accumulating data among the students. Results: Overweight and obese students were more likely to have eating disorders than non-overweight students (OR=3.21; 95% CI: 1.27-8.08). Mental health was associated with eating disorders. Specifically, students with symptoms of depression were 2.43 times more likely to have eating disorders than those without symptoms of depression, students with symptoms of anxiety had higher odds of eating disorders than those without anxiety (OR=2.29, 95% CI: 1.15-4.55), students experiencing stress had a 2.45-fold higher risk of eating disorders compared with stress-free students. In addition, sleep quality was also associated with eating, students with poor sleep quality had 2.83 times higher odds of eating disorders than those with good sleep quality. Conclusions: The presence, along with the severity of these factors, contributed to an increased risk of eating disorders.
Quang Minh Tran, Manh Duy Phung, Khanh Ly Nguyen, An Tuan Nguyen, Phuong Anh Chu, Duc Thai Nguyen, Samath Sony, Phong Tuc Vu*