Search Results (22)

The present study deals with the fabrication of activated carbon from longan peels (LPAC) using a phosphoric acid (H₃PO₄) activation method and an evaluation of LPAC’s capability for the adsorption of Reactive Black 5 (RB5) dye from aqueous solutions. The synthesized LPAC was characterized using XRD, SEM, FT-IR, and EDX, confirming a porous, carbon-rich structure with the dominant elemental composition of carbon (85.21%) and oxygen (12.43%), and a surface area of 1202.38 m²/g. Batch adsorption experiments revealed that optimal performance was achieved at pH 3.0, with equilibrium reached after 240 min. The experimental data were well fitted to the Elovich model p, suggesting a heterogeneous adsorption process with diffusion limitations. The intraparticle diffusion model further supported a multi-stage mechanism involving both film diffusion and intraparticle transport. Isotherm studies conducted at varying temperatures (293–323 K) showed a maximum adsorption capacity exceeding 370 mg/g. The adsorption data fit best with the Freundlich (R² = 0.962) and Temkin (R² = 0.970) models, indicating multilayer adsorption on a heterogeneous surface. Thermodynamic analysis revealed that the adsorption process was spontaneous and endothermic, with ΔG° values ranging from −23.15 to −26.88 kJ/mol, ΔH° = 14.23 kJ/mol, and ΔS° = 0.127 kJ/mol×K, consistent with physisorption as the dominant mechanism. Predictive modeling using an artificial neural network (ANN) achieved superior accuracy (R² = 0.989 for RRE; R² = 0.991 for q) compared to multiple linear regression (MLR). Calculation from ANN indicated that pH and contact time were the most influential factors for RB5 removal efficiency, while initial dye concentration and temperature were most critical for adsorption capacity. Furthermore, LPAC demonstrated excellent reusability, retaining over 83% removal efficiency after five adsorption–desorption cycles. These findings confirm that LPAC is an efficient and renewable adsorbent for the treatment of RB5 dye in wastewater treatment applications. Full article

Small wind turbines operating in low wind speed regions have not had any significant success. In addition, small wind speed regions occupy a large area of the world, so they represent a potential area for installing small wind turbines in the future. In this paper, a method to design an efficient airfoil for small wind turbines in low wind speed conditions using XFLR5 and CFD simulations is implemented. Because the impact of the airflow on the blade surface under low Re number conditions can change suddenly for small geometries, designing the airfoil shape to optimize the aerodynamic performance is essential. The tuning of the key geometric parameters using inversion techniques for better aerodynamic performance is presented in this study. A two-dimensional model was used to consider the airflow on the airfoil surface with differences in the angle of attack. The original S1010 airfoil was used to design a new airfoil for increasing the aerodynamic efficiency by using V6.57 XFLR5 software. Subsequently, the new VAST-EPU-S1010 airfoil model was adjusted to the maximum thickness and the maximum thickness position. It was simulated in low wind speed conditions of 4–6 m/s by a computational fluid dynamics simulation. The lift coefficient, drag coefficient, and C_L/C_D coefficient ratio were evaluated under the effect of the angle of attack and the maximum thickness by using the k-ε model. The simulation results show that the VAST-EPU-S1010 airfoil achieved the greatest aerodynamic efficiency at an angle of attack of 3°, a maximum thickness of 8%, and a maximum thickness position of 20.32%. The maximum value of C_L/C_D of the new airfoil at 6 m/s was higher than at 4 m/s by about 6.25%. Full article

This study investigated the use of chicken egg white (CEW) waste immobilized on weak acidic nanofiber membranes for removing the anionic acid orange 7 (AO7) dye in batch and continuous flow modes. Different experiments were conducted to evaluate the effectiveness of CEW-modified nanofiber membranes for AO7 removal, focusing on CEW immobilization conditions, adsorption kinetics, and thermodynamics. The CEW-modified nanofiber membrane (namely NM-COOH-CEW) exhibited a maximum AO7 adsorption capacity of 589.11 mg/g within approximately 30 min. The Freundlich isotherm model best represented the equilibrium adsorption data, while the adsorption kinetics followed a pseudo-second-order rate model. Breakthrough curve analysis using the Thomas model and the bed depth service time (BDST) model showed that the BDST model accurately described the curve, with an error percentage under 5%. To investigate AO7 elution efficiency, different concentrations of organic solvents or salts were tested as eluents. The NM-COOH-CEW nanofiber membrane exhibited promising performance as an effective adsorbent for removing AO7 dye from contaminated water. Full article

COVID-19 significantly disrupted tuberculosis (TB) services in Vietnam. In response, the National TB Program (NTP) integrated TB screening using mobile chest X-rays into COVID-19 vaccination events. This prospective cohort study evaluated the integrated model’s yield, treatment outcomes, and costs. We further fitted regressions to identify risk factors and conduct interrupted time-series analyses in the study area, Vietnam’s eight economic regions, and at the national level. At 115 events, we conducted 48,758 X-ray screens and detected 174 individuals with TB. We linked 89.7% to care, while 92.9% successfully completed treatment. The mean costs per person diagnosed with TB was $547. TB risk factors included male sex (aOR = 6.44, p < 0.001), age of 45–59 years (aOR = 1.81, p = 0.006) and ≥60 years (aOR = 1.99, p = 0.002), a history of TB (aOR = 7.96, p < 0.001), prior exposure to TB (aOR = 3.90, p = 0.001), and symptomatic presentation (aOR = 2.75, p < 0.001). There was a significant decline in TB notifications during the Delta wave and significant increases immediately after lockdowns were lifted (IRR(γ₁) = 5.00; 95%CI: (2.86, 8.73); p < 0.001) with a continuous upward trend thereafter (IRR(γ₂) = 1.39; 95%CI: (1.22, 1.38); p < 0.001). Similar patterns were observed at the national level and in all regions but the northeast region. The NTP’s swift actions and policy decisions ensured continuity of care and led to the rapid recovery of TB notifications, which may serve as blueprint for future pandemics. Full article

This study aimed to assess the effects of hexavalent chromium on zebrafish (Danio rerio) embryo development. The zebrafish embryos were treated with solutions containing chromium at different concentrations (0.1, 1, 3.125, 6.25, 12.5, 50, and 100 µg/mL). The development of zebrafish embryos was estimated by the determination of survival rate, heart rate, and the measurement of larvae body length. Real time RT-PCR and Western blot were performed to assess the expression of apoptosis- and antioxidant-related genes. The results showed that the reduced survival rate of zebrafish embryos and larvae was associated with an increase in chromium concentration. The exposure of higher concentrations resulted in a decrease in body length of zebrafish larvae. In addition, a marked increase in heart rate was observed in the zebrafish larvae under chromium treatment, especially at high concentrations. The real-time RT-PCR analysis showed that the transcript expressions for cell-cycle-related genes (cdk4 and cdk6) and antioxidant-related genes (sod1 and sod2) were downregulated in the zebrafish embryos treated with chromium. Western blot analysis revealed the upregulation of Caspase 3 and Bax, while a downregulation was observed in Bcl2. These results indicated that hexavalent chromium induced changes in zebrafish embryo development by altering apoptosis- and antioxidant-related genes. Full article

Removing antibiotics from water is critical to prevent the emergence and spread of antibiotic resistance, protect ecosystems, and maintain the effectiveness of these vital medications. The combination of ozone and electrocoagulation in wastewater treatment provides enhanced removal of contaminants, improved disinfection efficiency, and increased overall treatment effectiveness. In this work, the removal of sulfamethoxazole (SMX) from an aqueous solution using an ozone–electrocoagulation (O–EC) system was optimized and modeled. The experiments were designed according to the central composite design. The parameters, including current density, reaction time, pH, and ozone dose affecting the SMX removal efficiency of the OEC system, were optimized using a response surface methodology. The results show that the removal process was accurately predicted by the quadric model. The numerical optimization results show that the optimum conditions were a current density of 33.2 A/m², a time of 37.8 min, pH of 8.4, and an ozone dose of 0.7 g/h. Under these conditions, the removal efficiency reached 99.65%. A three-layer artificial neural network (ANN) with logsig-purelin transfer functions was used to model the removal process. The data predicted by the ANN model matched well to the experimental data. The calculation of the relative importance showed that pH was the most influential factor, followed by current density, ozone dose, and time. The kinetics of the SMX removal process followed the first-order kinetic model with a rate constant of 0.12 (min⁻¹). The removal mechanism involves various processes such as oxidation and reduction on the surface of electrodes, the reaction between ozone and ferrous ions, degradation of SMX molecules, formation of flocs, and adsorption of species on the flocs. The results obtained in this work indicate that the O–EC system is a potential approach for the removal of antibiotics from water. Full article

Research has shown that natural disasters can be prevented or mitigated effectively through education which provides knowledge and skills for the young generation to protect themselves and act to protect the community. The current study investigated the level of natural-disaster-prevention literacy and analyzed its predictors among high school students in Vietnam. This study adopted a cross-sectional school-based design, using an online survey. There were 807 students from seven public schools participating in this study. The results show that the natural-disaster-prevention knowledge, perception, skills, and overall literacy are above average, with knowledge having the highest score. Significant differences exist in natural-disaster-prevention literacy and its components by gender, grade, location, and residence. Age, location, residence, knowledge, and perception can predict participants’ skills of natural-disaster prevention. This study highlights the necessity of teaching natural-disaster prevention in schools, across grades, and focusing on providing the students with the knowledge and perception needed to improve their natural-disaster-prevention skills. This will contribute to helping the country meet the goal of education for sustainable development. Full article

Background and Objectives: To determine the antibiotic resistance rate of H. pylori among patients with peptic ulcer. Materials and Methods: A cross-sectional monocentric study was conducted from January to December 2021 among patients aged from 16 years with gastrointestinal symptoms and esophagogastroduodenoscopy. Gastric mucosa biopsies were collected at the edges of the ulcer or at lesion sites for H. pylori culture. Five antibiotics (amoxicillin (AMX), clarithromycin (CLR), metronidazole (MTZ), levofloxacin (LEV), and tetracycline (TET)) were selected for antibiotic susceptibility testing. Results: One hundred and twenty-five patients were included, and the sex ratio was 0.6. Their mean age was 47.3 ± 14.2 years. All of the participants had gastritis, and 24.0% had duodenitis. A total of 21.6% of patients had a duodenal ulcer, and 12.8% had an antral ulcer. A total of 40 specimens have grown in H. pylori culture. The proportion of resistance to AMX, CLR, MTZ, LEV, and TET was 27.5%, 50%, 67.5%, 35%, and 5%, respectively. The proportion of multidrug resistance was 22.5%. The proportion of double resistance to AMX + CLR was 20.0%, AMX + MTZ was 15.0%, AMX + LEV was 2.5%, CLR + MTZ was 32.5%, and TET + MTZ was 5.0%. Conclusions: Our research results show that the treatment with MTX-TET or LVX-AMOX has the highest sensitivity rate. Therefore, practitioners should refer to these regimes to eradicate H. pylori in patients with gastric and duodenal ulcers. The reports on H. pylori eradication from different geographic areas show heterogeneous results. Therefore, continuous monitoring of antibiotic resistance of H. pylori in each population is very important. Having evidence helps clinicians to treat patients most effectively, reduce treatment costs, and limit the rate of antibiotic resistance. Full article

Bank stability is a goal that bank managers aim for in addition to the goal of maximizing shareholder value. To achieve this goal, commercial banks have applied various solutions, including corporate governance because corporate governance plays an important role in the business activities of an enterprise in general as well as in that of a commercial bank in particular. The purpose of this paper is to investigate the impact of corporate governance on the stabilities of Vietnamese commercial banks in the period from 2009 to 2020. Using hand-collected data from 25 commercial banks in Vietnam, by system GMM estimation and the Bayesian Mixed-Effects approach, the paper identifies the characteristics of corporate governance affecting bank stability. Board size, women board members, and board members’ education have a positive impact, and dependent board and foreign board members have a negative impact on bank stability. Our findings show important evidence for an emerging country, such as Vietnam. From the empirical results, the authors suggest several recommendations to maintain and enhance bank stability in the future time. Full article

Determination of the dynamics between microalgae and bacteria in pig farming biogas digestate is vital for a consistent and reliable application towards sustainable wastewater treatment and biofuel production. This study assesses the reliability of using physicochemical parameters as indicators for the rapid evaluation of microalgal bacterial dynamics in real digestate under impacts of light, nutrient loads, and N:P ratios. The relationship between variation profiles of nutrients, biomass and physicochemical properties in each experiment was analyzed. High light and high nutrient load enhanced biomass growth and nutrient removal rate. Ammonium addition (high N:P ratio) elevated NH₃ level which inhibited the growth of microalgae, subsequently reducing the biomass growth and nutrient removal. Low N:P ratio triggered the accumulation of phosphorus and the growth of chlorophyll-a but exerted little influence on treatment. Variation profiles of dissolved oxygen, nutrient and biomass were highly consistent in every experiment allowing us to identify the shift from microalgal to bacterial predomination under unfavorable conditions including low light intensity and high N:P ratio. Strong linear correlation was also found between total nitrogen removal and electrical conductivity (R² = 0.9754). The results show the great potential of rapid evaluation of microalgal bacterial dynamics for large scale system optimization and modelling. Full article

We investigated changes in some laboratory indices and the liver histology of chronic hepatitis patients who were exposed to dioxin. In 2014, we collected liver biopsy samples for histopathological examination from 33 chronic hepatitis patients living around the Da Nang Airbase, which is a dioxin-contaminated area due to the herbicide spraying in Vietnam. Dioxin exposure was measured by its levels in the blood. METAVIR classification was used to clarify the liver fibrosis stage. Laboratory tests included ten biochemical and six hematological indices that were measured in the blood. A regression linear model and binary logistic regression were used for data analysis. The observed alterations in the liver at the histological level mainly comprised hydropic degenerative hepatocytes, lymphocytes and polynuclear leukocytes surrounding the liver cells and granular and lipoic degeneration. In addition, increased TCDD levels were associated with increasing aminotransferase (AST), alanine aminotransferase, protein and total bilirubin levels and liver fibrosis stage. Similarly, increased TEQ-PCDD/Fs levels were associated with higher levels of AST and protein and liver fibrosis stage. In conclusion, dioxin exposure altered the liver histology and increased some biochemical marker indices and the liver fibrosis stage of chronic hepatitis patients living in dioxin-contaminated areas in Da Nang, Vietnam. Full article

Imidacloprid, acephate, and carbaryl are common insecticides that are extensively used in planting mango, a well-known fruit in Vietnam, to ease mango hopper issues. The accurate detection of pesticide residues is critical for mango export to meet quality criteria. This study developed a novel SERS platform by using polydimethylsiloxane (PDMS) to simulate the rose petal structure incorporated with a silver coating layer and silver nanoparticles (AgNPs) to detect imidacloprid, acephate, and carbaryl in mango fruits. In this paper, the rose petal PDMS/Ag-AgNPs replica was considered the most efficient substrate for SERS measurement with an EF of 4.7 × 10⁷. The Raman spectra of the three insecticides obtained from the PDMS/Ag-AgNPs substrate were clearly observed with their characteristic peaks of 1105 cm⁻¹ for imidacloprid, 1083 cm⁻¹, and 1579 cm⁻¹ for acephate, and 727 cm⁻¹ and 1378 cm⁻¹ for carbaryl. The application of PDMS/Ag-AgNPs substrate in quantitative analysis of the three pesticides in mango fruit was evaluated. As a result, the limit of detection was 0.02 mg/kg for imidacloprid, 5 × 10⁻⁵ mg/kg for acephate, and 5 × 10⁻³ mg/kg for carbaryl. The SERS result also revealed that the pesticide residues in the mango sample were within an acceptable limit. This suggested the possibility of the rose petal PDMS/Ag-AgNPs replica for rapid quantification of pesticide residues not only in mango fruit but also in many other agricultural products. Full article

In Vietnam, data on the risk factors for diarrhea at the community level remain sparse. This study aimed to provide an overview of diarrheal diseases in an agricultural community in Vietnam, targeting all age groups. Specifically, we investigated the incidence of diarrheal disease at the community level and described the potential risk factors associated with diarrheal diseases. In this prospective cohort study, a total of 1508 residents were enrolled during the 54-week study period in northern Vietnam. The observed diarrheal incidence per person-year was 0.51 episodes. For children aged <5 years, the incidence per person-year was 0.81 episodes. Unexpectedly, the frequency of diarrhea was significantly higher among participants who used tap water for drinking than among participants who used rainwater. Participants who used a flush toilet had less frequent diarrhea than those who used a pit latrine. The potential risk factors for diarrhea included the source of water used in daily life, drinking water, and type of toilet. However, the direct reason for the association between potential risk factors and diarrhea was not clear. The infection routes of diarrheal pathogens in the environment remain to be investigated at this study site. Full article

Nanosized multi-drug delivery systems provide synergistic effects between drugs and bioactive compounds, resulting in increased overall efficiency and restricted side effects compared to conventional single-drug chemotherapy. In this study, we develop an amphiphilic heparin-poloxamer P403 (HP403) nanogel that could effectively co-load curcuminoid (Cur) and cisplatin hydrate (CisOH) (HP403@CisOH@Cur) via two loading mechanisms. The HP403 nanogels and HP403@CisOH@Cur nanogels were closely analyzed with ¹H-NMR spectroscopy, FT-IR spectroscopy, TEM, and DLS, exhibiting high stability in spherical forms. In drug release profiles, accelerated behavior of Cur and CisOH at pH 5.5 compared with neutral pH was observed, suggesting effective delivery of the compounds in tumor sites. In vitro studies showed high antitumor activity of HP403@CisOH@Cur nanogels, while in vivo assays showed that the dual-drug platform prolonged the survival time of mice and prevented tail necrosis. In summary, HP403@CisOH@Cur offers an intriguing strategy to achieve the cisplatin and curcumin synergistic effect in a well-designed delivery platform that increases antitumor effectiveness and overcomes undesired consequences caused by cisplatin in breast cancer treatment. Full article

An online cross-sectional survey using a “snowball” sampling method was carried out to assess the adherence to COVID-19 preventive measures among dental care workers (DCWs) during the pandemic. Six questions concerning the COVID-19 preventive guidelines issued by the Vietnam Ministry of Health were used to evaluate DCWs’ adherence to preventive measures at dental care clinics. The quality of life of DCWs was assessed using the WHO-5 questionnaire and was defined as low if the total score was less than 13 points. Factors relating to adherence to COVID-19 prevention measures of DCWs were determined by multivariate linear regression analysis. In total, 514 DCWs completed the questionnaire. A total of 37% DCWs rated their quality of life as low. Regression analysis suggested that older age, a better quality of life, living in an urban area, and training on COVID-19 prevention were associated with better adherence to COVID-19 preventive measures, while being a dentist and lack of personal protective equipment was associated with less adherence to COVID-19 preventive measures. The pandemic had a significant negative impact on the physical and mental health of DCWs. Therefore, specific national guidelines for the prevention and control of the spread of COVID-19 in dental facilities should be issued. Full article