Search Results (125)

Background: Community-acquired pneumonia (CAP) is the leading cause of death in infants aged 1–59 months. Concurrent with this, there is a need to prescribe antibiotics wisely in Vietnam due to concerns with rising antimicrobial resistance (AMR). Consequently, an urgent need has arisen to treat patients according to agreed guidelines. The aim of this study was to investigate the current management of infants under five years old with CAP in Vietnam as well as identify possible obstacles to adhering to national guidelines. Methods: A mixed-method approach was used incorporating both quantitative and qualitative data analysis in a leading hospital in Vietnam, which influences others. Data from 108 pediatric patient records were collected and analyzed. Subsequently, in-depth interviews were conducted with pediatric doctors treating these patients to ascertain possible reasons for non-adherence to guidelines. Results: The mean age of children diagnosed with CAP was 27.94 ± 12.99 months, with 82.4% having non-severe CAP, and 41.7% of children had previously used antibiotics before hospitalization. The median length of hospital stay was 7 days. All children were prescribed antibiotics, 91.4% of children received these initially intravenously, with third-generation cephalosporins being the most (91.7%) commonly prescribed. Cefoperazone/sulbactam was the most frequently prescribed (48.2%) antibiotic. However, on 96.1% of occasions cefoperazone/sulbactam was given at higher doses than the label instructions. Overall, 73.3% of antibiotics prescribed were “Watch” antibiotics. In addition, the proportion of initial antibiotic regimens that were consistent with current national guidelines was only 4.63%. Conclusions: There were considerable concerns with low adherence rates to current guidelines alongside high rates of prescribing of injectable third-generation cephalosporins due to various internal and external barriers. Antimicrobial stewardship programs with updated national guidelines are urgently needed in Vietnamese hospitals to treat CAP in children as part of ongoing measures to reduce increasing AMR rates. Such activities should also help improve antibiotic use in the community following improved education of trainee ambulatory care physicians regarding appropriate management of children with CAP. Full article

The mud crab (Scylla paramamosain), also known as the mangrove crab, thrives in shallow mangrove forests, subtidal zones, and muddy intertidal habitats. It is a highly valuable species in the mangroves and estuaries of tropical regions and is in high demand in Vietnam’s coastal markets. This study provides a comprehensive analysis of the key factors influencing consumer behavior and purchasing decisions regarding mud crabs in Vietnam’s three largest cities: Can Tho City, Ho Chi Minh City, and Hanoi Capital. To achieve this, the research employs rigorous analytical methods, including Cronbach’s alpha reliability test, principal component analysis, and multivariate regression analysis, to identify the primary determinants of consumer behavior and purchasing preferences for fresh mud crabs. The multiple regression analysis reveals two key factors that significantly influence consumer choices: nutritional knowledge and convenience awareness. Most of consumers perceive fresh mud crabs as superior in quality, expecting them to offer greater freshness; higher levels of protein, amino acids, and minerals; as well as excellent flesh texture and enhanced palatability. Based on these findings, two strategic directions are proposed for the sustainable development of Vietnam’s crab industry: (1) improving the nutritional quality of crab products to align with consumer expectations for health benefits and (2) enhancing the distribution network and diversifying product offerings to improve accessibility and convenience for consumers. Full article

Single-use plastics (SUPs) are deeply embedded in everyday consumption in rapidly developing Asian cities, yet their widespread use contributes to marine debris, microplastic pollution, and health risks. This study aimed to inform evidence-based policymaking to mitigate marine plastic pollution in the ASEAN+3 region. Stratified random sampling surveys (n = 1492) were conducted both face to face and online across five representative cities between September 2022 and February 2023. We quantified and compared the consumption and disposal patterns across nine SUP categories, assessed demographic influences, evaluated the impact of COVID-19, and derived insights for targeted policy interventions. Non-parametric tests were used to evaluate the differences. The results reveal significant inter-city variation: Shanghai and Harbin reported high overall SUP use despite a lower consumption of plastic shopping bags; Hanoi and Depok showed lower overall use but distinct preferences for plastic shopping bags and party cups; and Phnom Penh had the highest consumption of plastic shopping bags, bottles, and straws. Plastic shopping bags were the most used item in all cities (18–34 bags per week), with no significant differences between urban and rural areas, ages, or genders. In contrast, urban residents reported a higher use of plastic takeout containers, cutlery, coffee cups, and party cups. The COVID-19 pandemic notably reshaped SUP consumption patterns. Additionally, over half of SUPs were disposed of without proper separation. These findings underscore the need for flexible, phased, and context-specific interventions to support a resilient circular economy. Full article

Electrical discharge machining represents a non-conventional machining process, specifically designed for the effective fabrication of materials that are difficult to machine and for components with complex geometries. Many studies have been carried out that combine electrical discharge machining with the ultrasonic vibration of electrodes. Nevertheless, most of these investigations have concentrated on the processing of hole or cavity components. This document presents an experimental study focused on the design of an electrode holder for ultrasonic vibration electrical discharge machining, focusing on the machining of cylindrical surfaces. This study involved a two-stage design process for the electrode holder, aimed at determining the optimal length to achieve the maximal material removal rate and to ensure surface roughness. The novel aspect of this study is that it is the first to be published on the use of ultrasonic vibration in the electrical discharge machining process for processing cylindrical surfaces. Furthermore, splitting the electrode holder design process into two stages (theoretical calculation and experimental determination) made it possible to identify an electrode holder design for ultrasonic vibration electrical discharge machining that increased the MRR by 35.5% while maintaining SR values that were similar to those produced during the electrical discharge machining without ultrasonic vibration. Full article

This study explores the integration of a custom-designed pneumatic spring into a car-seat cushion and its interaction with a simplified human body model using the Finite Element Method (FEM). A 3D half-symmetry FEM framework, developed from experimental data, ensured computational efficiency and convergence. This research bridged experimental and numerical approaches by analyzing the contact pressure distributions between a seat cushion and a volunteer with representative biometric characteristics. The model incorporated two material groups: (1) human body components (bones and muscles) and (2) seat cushion materials (polyurethane foam, latex, and fabric tape). Mechanical properties were obtained from both the literature and experiments, and simulations were conducted using MSC.Marc software under realistic boundary and initial conditions. The simulation results exhibited strong agreement with experimental data, validating the model’s reliability in predicting contact pressure distribution and optimizing seat cushion designs. Contrary to the conventional notion that uniformly distributed contact pressure inherently enhances comfort, this study emphasizes that the precise localization of pressure plays a crucial role in static and long-term seating ergonomics. Both experimental and simulation results demonstrated that modulating the pneumatic spring’s internal pressure from 0 kPa to 25 kPa altered peak contact pressure by approximately 3.5 kPa (around 20%), significantly influencing pressure redistribution and mitigating high-pressure zones. By validating this FEM-based approach, this study reduces dependence on physical prototyping, lowering design costs, and accelerating the development of ergonomically optimized seating solutions. The findings contribute to a deeper understanding of human–seat interactions, offering a foundation for next-generation automotive seating innovations that enhance comfort, fatigue reduction, and adaptive pressure control. Full article

The HIV epidemic remains a major public health issue globally and in Vietnam. This study assesses changes in HIV/AIDS-related mortality rates over time in Lang Son Province, Vietnam, from 2005–2018. We performed a descriptive epidemiological study using a population-based mortality registration system to examine HIV/AIDS-related mortality. HIV/AIDS-related mortality was converted to a crude and adjusted rate per 100,000 person-years using the World Health Organization’s standard population for 2000–2025. The mortality rate ratio and 95% confidence interval were estimated to examine the province’s time trend from 2005 to 2018. The adjusted mortality rate for HIV/AIDS in Lang Son Province was 12.3 and 2.4 per 100,000 for men and women, respectively, with a male-to-female ratio of 5.1. The province experienced a 94% reduction in HIV/AIDS-related deaths between 2005 and 2018. The mortality rate ratio for 2018 compared to 2005 was lower for men (0.056, 95% CI: 0.029, 0.110) than for women (0.080, 95% CI: 0.019, 0.338). The findings show a gradual decline in HIV/AIDS-related mortality rates in Lang Son Province, Vietnam. However, significant gender disparities in mortality remain a major concern, and HIV remains a significant burden. This highlights the urgency for major efforts to prevent HIV transmission and address these disparities to effectively end the HIV epidemic in Lang Son and throughout Vietnam. Full article

Hanoi is the capital of Vietnam, with a total area of 3359.82 km² and a population of about 8.4 million people. This is one of the most developed cities in Vietnam, with an urbanization rate of 60%. In this study, we investigated how developed and urbanized areas may influence lichen diversity in Hanoi. The lichen community from Hanoi was studied using three tree stands from each of five landscapes: natural vegetation, industrial parks, urban and rural areas, and roadsides. Lichen species and their cover abundance were recorded on tree trunks at heights from 30 to 150 cm above ground in ten host trees that were randomly selected for each replication. Sixty-seven lichen species, from sixteen families and eight orders, were recorded. Results showed urbanization and the development of industrial parks and transportation altered species composition, evidenced by a reduced number of lichen species. Natural forests sustained the highest lichen diversity measured. These results suggest that a greater diversity of lichen can be preserved in natural forests, if that natural vegetation is effectively managed and conserved. Full article

The burden of herpes zoster (HZ) is recognized worldwide; however, there is seemingly limited information on incidence and vaccination practices in Southeast Asia (SEA). A scientific workshop was held by the Zoster Experts’ Network to exchange and consolidate insights on the burden of HZ and the patient pathway in SEA. The workshop included practicing clinical experts and public health specialists/epidemiologists from Indonesia, Malaysia, the Philippines, Thailand, and Vietnam. It aimed to identify gaps in the literature, outline patient pathways, and evaluate HZ vaccine recommendations among these countries. Consensus was identified on the substantial lack of epidemiological data on HZ in SEA and the need to investigate the impact of age, immunocompromising conditions, and comorbidities on the incidence and severity of HZ in the region. However, available data in SEA did indicate a rising disease and socioeconomic burden of HZ, with concerns that current treatment strategies for HZ are suboptimal. The HZ patient pathways generated by the experts highlighted common themes and differences between the five countries. Furthermore, the experts highlighted the lack of awareness of HZ and its impact on patients’ quality of life, among patients and healthcare professionals. Evaluation of the current local HZ vaccine recommendations further showed differences in age and the inclusion of at-risk populations between countries. The workshop outcomes emphasize the need for further HZ surveillance in SEA. Efforts to align and address leakage within the patient pathway and raise awareness on the impact of HZ should be prioritized. Awareness initiatives and alignment on vaccine recommendations are also needed. Full article

The temperature estimation within asphalt concrete (AC) overlaid on cement-stabilized bases (CSB) is necessary for pavement analysis and design. However, the impact of different CSB gradations and rubberized CSB on AC temperature has not been thoroughly investigated. This study aims to clarify this effect by examining two types of CSB with nominal particle aggregate sizes of 25 mm and 31.5 mm, as well as the substitution of 5%, 10%, and 20% graded aggregates with rubber aggregates (RA) in CSB Dmax 25 using Ansys-based numerical simulations. The modelling also investigated 11 scenarios with different AC thicknesses (h_AC) ranging from 6 to 26 cm. The results indicated that CSB Dmax 31.5 reduced the daily maximum temperature fluctuation at the bottom of the AC (∆T_bottomAC) by approximately 8% compared to CSB Dmax 25. The inclusion of 5% RA in CSB Dmax 25 decreased ∆T_bottomAC by up to 20%. Additionally, the rubberized CSB increased the maximum temperature gradient between the top and bottom of the AC (ΔT_maxAC) by 9.5% with 5% RA and a 6 cm AC thickness; however, this increase was insignificant when h_AC exceeded 12 cm. This study also proposed the use of artificial neural network (ANN) models to predict the AC’s temperature distribution based on depth, the time of day, surface paving temperatures, and h_AC. The proposed ANN model demonstrated high accuracy (R² = 0.996 and MSE = 0.000685),which was confirmed by the numerical simulations, with an acceptable RMSE ranging from 0.28 °C to 0.67 °C. Full article

When optimizing a mechanical device, the symmetry principle provides important guidance. Minimum gearbox mass and maximum gearbox efficiency are two single objectives that need to be achieved when designing a gearbox, and they are not compatible. In order to address the multi-objective optimization (MOO) problem with the above single targets involved in building a two-stage helical gearbox with second-stage double gear sets, this work presents a novel application of the multi-criteria decision-making (MCDM) method. This study’s objective is to identify the best primary design elements that will increase the gearbox efficiency while lowering the gearbox mass. To carry this out, three main design parameters were selected: the first stage’s gear ratio and the first and second stages’ coefficients of wheel face width (CWFW). Furthermore, a study focusing on two distinct goals was carried out: the lowest possible gearbox mass and the highest possible gearbox efficiency. Furthermore, the two stages of the MOO problem are phase 1 and phase 2, respectively. Phase 2 solves the single-objective optimization issue to minimize the difference between variable levels and the MOO problem to determine the optimal primary design factors. To solve the MOO problem, the EAMR (Evaluation by an Area-based Method of Ranking) method was also chosen. The following are important features of this study: First, a MCDM method (EAMR technique) was successfully applied to solve a MOO problem for the first time. Secondly, this work explored the power losses during idle motion to calculate the efficiency of a two-stage helical gearbox with second-stage double gear sets. This study’s findings were used to identify the optimal values for three important design variables to design a two-stage helical gearbox with second-stage double gear sets. Full article

This paper provides a novel application of the multi-criteria decision-making (MCDM) method to the multi-objective optimization problem (MOOP) of creating a two-stage helical gearbox (TSHG) with second-stage double gear sets (SDGSs). The aim of the study is to determine the optimum major design components for enhancing the gearbox efficiency while reducing the gearbox volume. In this work, three primary design parameters are chosen to accomplish this: the gear ratio of the first stage and the coefficients of the wheel face width (CWFW) of the first and second stages. Additionally, the study is conducted with two distinct objectives in mind: the lowest gearbox volume and the maximum gearbox efficiency. Moreover, phase 1 and phase 2, respectively, are the two stages of the MOOP. Phase 2 handles the MOOP to identify the ideal primary design factors as well as the single-objective optimization problem to minimize the difference between the variable levels. Additionally, the Multi-Attributive Ideal–Real Comparative Analysis (MAIRCA) approach is selected to deal with the MOOP. The results of the study are utilized to determine the ideal values for three crucial design parameters in order to create a TSHG with SDGSs. Full article

In order to address the Multi-Objective Optimization Problem (MOOP) in building a two-stage helical gearbox, this work presents a novel application of the Multi-Criterion Decision-Making (MCDM) method. The aim of the study is to determine the optimal primary design factors that will increase gearbox efficiency while decreasing gearbox volume. Three main design parameters were chosen for assessment in this work: the first stage’s gear ratio, and the first and second stages’ Coefficients of Wheel Face Width (CWFW). In addition, the MOOP is divided into two phases: phase 1 solves the single-objective optimization problem to reduce the gap between variable levels, and phase 2 solves the MOOP to determine the optimal primary design factors. Furthermore, the Entropy approach was picked to compute the weight criteria, and the MARCOS method was chosen as an MCDM method to handle the multi-objective optimization issue. The following are important characteristics of the study: Firstly, the MCDM method (MARCOS technique) was successfully applied to solve a MOOP for the first time. Secondly, this work has looked into power losses during idle motion to calculate the efficiency of a two-stage helical gearbox. The results of the study were used in the design of a two-stage helical gearbox in order to identify the optimal values for three important design parameters. Full article

The multi-criteria decision-making (MCDM) method was applied in a novel way in this study to the multi-objective optimization problem (MOOP) of designing a two-stage helical gearbox with double gear-sets in the second stage. Finding the best fundamental components to increase gearbox efficiency and decrease gearbox cross-section area was the aim of this study. Three main design factors were chosen for investigation in this work: the first stage gear ratio and the first and second stage coefficients of wheel face width (CWFW). Phase 1 solves the single-objective optimization problem to reduce the gap between variable levels, and phase 2 solves the MOOP to determine the optimal critical design factors. This additionally splits the MOOP into two phases. Additionally, the TOPSIS method was used as an MCDM approach to address the multi-objective optimization issue, and the entropy approach was used to compute the weight criteria. In this study, gearbox efficiency is calculated by considering power losses during idle motion. The multi-objective optimization of a helical gearbox with second stage double gear-sets is addressed using the TOPSIS technique for the first time. Full article

This paper provides a novel application of a multi-criterion decision-making (MCDM) method to the multi-objective optimization problem of designing a two-stage helical gearbox. This study’s goal is to identify the ideal primary design elements that increase gearbox efficiency while reducing the gearbox cross-section area. In this work, three primary design parameters were selected for investigation: the gear ratio of the first stage and the coefficients of wheel face width (CWFW) of the first and second stages. The multi-objective optimization problem was further split into two phases: phase 1 solved the single-objective optimization problem of minimizing the gap between the variable levels, and phase 2 solved the multi-objective optimization issue of identifying the ideal key design factors. Moreover, the multi-objective optimization problem was handled by the SAW method as an MCDM approach, and the weight criteria were computed using the entropy approach. This study’s significant characteristics are as follows: First, a multi-objective optimization problem was successfully solved using the MCDM approach (SAW technique) for the first time. Second, the power losses in idle motion were investigated in this work in order to determine the efficiency of a two-stage helical gearbox. From this study’s findings, the ideal values for three major design parameters can be determined for the design of a two-stage helical gearbox. Full article

One of the largest issues facing countries, particularly emerging nations with high population, production, and consumption growth, is an inadequate waste management system (WMS). This paper analyzes the development of the waste management systems of nine capital cities in the Association of Southeast Asian Nations (ASEAN) region by using a recently developed approach, the Waste Management System–Development Stage Concept. This concept comprises five development stages and various components, including Collection and Transport, Waste Disposal, Energy Recovery, Waste Recycling, and Waste Prevention and Reuse. The findings indicate that in terms of waste collection, waste disposal, and energy recovery, Singapore is at a higher development stage (Stage 5) and is more advanced than other ASEAN cities. For most of the components, Bangkok, Jakarta, Kuala Lumpur, and Manila fall into stages 2 to 4, whereas the early development stages 1 to 3 are present in Bandar Seri Begawan, Hanoi, Phnom Penh, and Vientiane. The results will be used to determine the next steps in developing the WMSs, including the introduction of separate collection for recycling or the installation of a waste-to-energy plant. The environmental impact of each measure will be later assessed using the LCA approach, and the most effective measures shall be identified in future studies. Full article