136 research outputs found

    Morphodynamic modeling and causes of closure of My A inlet

    Get PDF
    Morphodynamics and sediment transport of the My A inlet in the low flow season are modeled using Delft3D. The simulation model takes into account the forcing of waves, tides and river flows. Model outputs of sediment transport and morphological changes of allow analysing the mechanism and cause of inlet closure. The analysis shows that longshore sediment is accreted on the northern side of the inlet both on the ebb tidal delta and along the north coast, but onshore sediment transport by wave reworking is the main process to close the inlet

    HYDROGEN DEFECTS ON THE SURFACE OF LEAD-FREE FERROELECTRIC Na0.5_{0.5}Bi0.5_{0.5}TiO3_3 MATERIALS

    Get PDF
    Hydrogen atomic chemisorption and adsorption at all possible vacancy sites on the surface of perovskite Na0.5Bi0.5TiO3 (110) were explored using calculations from density functional theory. Our calculations reveal that a pristine Na0.5Bi0.5TiO3 (110) surface can exhibit direct and indirect transitions characterized by optical bandgaps of 2.68 eV and 2.75 eV, respectively. The density of states of the Na0.5Bi0.5TiO3 (110) surface indicates predominant electron transitions from O-2p valence bands to Ti-3d and Bi-6p conduction bands in the low-energy range. Hydrogen substitution at vacancies can induce magnetism, whereas hydrogen adsorption enhances both the magnetism and conductivity of the surface system. In particular, the charge density reveals electron transfer between cations and hydrogen atoms, providing insight into the variations in hydrogen bonding properties in these surface systems. These observations expand our understanding of hydrogen chemisorption and adsorption on defect sites, providing a novel avenue for investigating and potentially developing environmentally friendly multiferroic materials for advanced electronic devices

    All-dielectric Metamaterial for Electromagnetically-induced Transparency in Optical Region

    Get PDF
    Metamaterial (MM) is emerging as a promising approach to manipulate electromagnetic waves, spanning from radio frequency to the optical region. In this paper, we employ an effect called electromagnetically-induced transparency (EIT) in all-dielectric MM structures to create a narrow transparent window in opaque broadband of the optical region (580-670 nm). Using dielectric materials instead of metals can mitigate the large non-radiative ohmic loss on the metal surface. The unit-cell of MM consists of Silicon (Si) bars on Silicon dioxide (SiO2_{2}) substrate, in which two bars are directed horizontally and one bar is directed vertically. By changing the relative position and dimension of the Si bars, the EIT effect could be achieved. The optical properties of the proposed MM are investigated numerically using the finite difference method with commercial software Computer Simulation Technology (CST). Then, characteristic parameters of MM exhibiting EIT effect (EIT-MM), including Q-factor, group delay, are calculated to evaluate the applicability of EIT-MM to sensing and light confinement

    Effects of medicinal plants mixture on growth performance, nutrient digestibility, blood profiles, and fecal microbiota in growing pigs.

    Get PDF
    peer reviewed[en] BACKGROUND AND AIM: Alternative natural materials to antibiotics for improving digestive health and growth performance are needed due to strengthening regulations related to the use of antibiotic growth promoters. The study aimed to evaluate the effects of medicinal plants mixture (60% Bidens pilosa L., 15% Urena lobata L., 15% Pseuderanthemum palatiferum, 5% Ramulus cinnamomi, and 5% Star anise) as alternative growth promotors on animal health, nutrient digestibility, blood parameters, and growth performance of growing pigs. MATERIALS AND METHODS: The study was conducted, from April 2020 to June 2020, at a private pig production farm located in Cam Giang district Hai Duong Province, Vietnam. Forty-eight 10-week-old crossbred (♂Duroc×♀ [Landrace×Yorkshire]) pigs, average initial body weight 30.3±1.42 kg, were randomly allocated to four dietary groups, three replicate pens per experimental group, with 4 pigs/pen. For 7 weeks, the pigs were fed a basal diet supplemented with the mixture at levels of 0, 20, 40, and 60 g/kg of feed. RESULTS: Final body weight, average daily gain, average daily feed intake, and feed conversion ratio, as well as apparent total tract digestibility of dry matter, organic matter, crude protein, ether extract, and gross energy were not significantly influenced by the diets (p>0.05). Inclusion of the plant mixture decreased significantly red blood cell count, blood cholesterol, urea nitrogen, and low-density lipoprotein (LDL) concentrations (p<0.05) compared with the control diet. No diet effect was observed on fecal Escherichia coli, Salmonella spp., Clostridium spp., and total bacteria counts. CONCLUSION: The incorporation of the plant mixture into the diet of growing pigs reduced serum cholesterol, LDL, and urea concentrations with no adverse effect on performance and nutrient digestibility.2. Zero hunge

    Ecological and behavioural risk factors of scrub typhus in central Vietnam: a case‑control study

    Get PDF
    Background: The risk factors for scrub typhus in Vietnam remain unknown. Scrub typhus caused by Orientia tsutsugamushi often presents as an undifferentiated febrile illness and remains under appreciated due to the limited availability of diagnostic tests. This tropical rickettsial illness is increasingly recognized as an important cause of non-malaria acute undifferentiated fever in Asia. This study aimed to investigate behavioural and ecological related risk factors of scrub typhus to prevent this potentially life-threatening disease in Vietnam. Methods: We conducted a clinical hospital-based active surveillance study, and a retrospective residence-enrolment date-age-matched case-control study in Khanh Hoa province, Vietnam, from August 2018 to March 2020. Clinical examinations, polymerase chain reaction and enzyme-linked immunosorbent assay IgM tests were applied to define cases and controls. All enrolled participants filled out a questionnaire including demographic socio-economic status, personal behaviors/protective equipment, habitat connections, land use, and possible exposure to the vector. Multivariable conditional logistic regression was used to define the scrub typhus associated risk factors. Results: We identified 44 confirmed cases and matched them with 152 controls. Among cases and controls, the largest age group was the 41-50 years old and males accounted for 61.4% and 42.8%, respectively. There were similarities in demographic characteristics between the two groups, with the exception of occupation. Several factors were significantly associated with acquisition of scrub typhus, including sitting/laying directly on household floor [adjusted OR (aOR) = 4.9, 95% CI: 1.6-15.1, P = 0.006], household with poor sanitation/conditions (aOR = 7.9, 95% CI: 1.9-32.9, P = 0.005), workplace environment with risk (aOR = 3.0, 95% CI: 1.2-7.6, P = 0.020), always observing mice around home (aOR = 3.7, 95% CI: 1.4-9.9, P = 0.008), and use of personal protective equipment in the field (aOR = 0.4, 95% CI: 0.1-1.1, P = 0.076). Conclusions: Ecological and household hygiene-related factors were more associated with scrub typhus infection,than individual-level exposure activities in the hyper-endemic area. These findings support local education and allow people to protect themselves from scrub typhus, especially in areas with limitations in diagnostic capacit

    Extraction of anthocyanins from Butterfly pea (Clitoria ternatea L. Flowers) in Southern Vietnam: Response surface modeling for optimization of the operation conditions

    Get PDF
    In this paper, the Response Surface Methodology (RSM), in conjunction with Central Composite Design (CCD), was used to optimize the extraction of anthocyanins from Butterfly pea (Clitoria ternatea L.Flowers) cultivated in Southern Vietnam. The effect of extraction temperatures of solvent ethanol (50-70 °C), duration of extraction (40-50 min) and solid-liquid ratios (20:1-30:1) was measured as independent variables on the total extraction anthocyanins in the response function. The highest anthocyanin content of 132.756 mg/L of butterfly pea anthocyanin was collected at the solid liquid ratio of 23:1, extraction time of 46 min, and temperature 60.6°C. Butterfly pea anthocyanins yield detailed significant correlation with high F values, low P values (<0.0001), and desirable determination coefficient (R2 = 0.9994)

    The Association of Cytokines with Severe Dengue in Children

    Get PDF
    Background: Dengue virus infection is a major public health problem. A hypothesis put forward for severe dengue is the cytokine storm, a sudden increase in cytokines that induces vascular permeability. Previous studies and our recent meta-analysis showed that IL-6, IL-8, IFNγ, TNFα, VEGF-A and VCAM-1 are associated with dengue shock syndrome. Therefore, in this study we aim to validate the association of these cytokines with severe dengue. Methods & Findings: In a hospital based-case control study in Vietnam, children with dengue fever, other febrile illness and healthy controls were recruited. Dengue virus infection was confirmed by several diagnostic tests. Multiplex immunoassay using Luminex technology was used to measure cytokines simultaneously. A positive association with dengue shock syndrome was found for VCAM-1, whereas a negative association was found for IFNγ. Furthermore, multivariate logistic analysis also showed that VCAM-1 and IFNγ were independently correlated with dengue shock syndrome. Conclusion: IFNγ and VCAM-1 were associated with dengue shock syndrome, although their role in the severe dengue pathogenesis remains unclear. Additional studies are required to shed further light on the function of these cytokines in severe dengue

    Criteria of “persistent vomiting” in the WHO 2009 warning signs for dengue case classification

    Get PDF
    Introduction: Dengue is a viral disease that spreads rapidly in the tropic and subtropic regions of the world and causes 22,000 deaths annually. In 2009, the World Health Organization (WHO) released a new classification of dengue infections, which divided them into three categories: dengue without warning sign (D), dengue with warning sign (DWS), and severe dengue (SD). However, researchers have been using different criteria to define persistent vomiting; therefore, we aimed to evaluate the ability of the number of vomiting times in early prediction of SD development among D/DWS patients. Method: A hospital-based cohort study was conducted in Ben Tre-south of Vietnam. We enrolled confirmed dengue patients with D and DWS at admission. The final classification was determined on the discharged day for every patient based on the classification of WHO 2009 without using vomiting symptom, using the receiver operating characteristic (ROC) curve to evaluate the ability of the number of vomiting times in early prediction of SD development among D/DWS patients. Result: The prevalence of vomiting symptom was higher in SD group than D/DWS group (92 versus 46 %, p = 0.006), and the median of the number of vomiting times was higher in SD group than D/DWS group (2.5 versus 0, p = 0.001). To distinguish SD from D/DWS, the ROC curve of the number of vomiting episodes showed that the area under the curve was 0.77; with the cut point of two, the sensitivity and specificity were 92 and 52 %, respectively. Conclusion: The number of vomiting times could be a good clinical sign which can early predict SD from the group of D/DWS. We suggest the definition of persistent vomiting should be vomiting two times or more per day

    Awareness and preparedness of healthcare workers against the first wave of the COVID-19 pandemic: A cross-sectional survey across 57 countries.

    Get PDF
    BACKGROUND: Since the COVID-19 pandemic began, there have been concerns related to the preparedness of healthcare workers (HCWs). This study aimed to describe the level of awareness and preparedness of hospital HCWs at the time of the first wave. METHODS: This multinational, multicenter, cross-sectional survey was conducted among hospital HCWs from February to May 2020. We used a hierarchical logistic regression multivariate analysis to adjust the influence of variables based on awareness and preparedness. We then used association rule mining to identify relationships between HCW confidence in handling suspected COVID-19 patients and prior COVID-19 case-management training. RESULTS: We surveyed 24,653 HCWs from 371 hospitals across 57 countries and received 17,302 responses from 70.2% HCWs overall. The median COVID-19 preparedness score was 11.0 (interquartile range [IQR] = 6.0-14.0) and the median awareness score was 29.6 (IQR = 26.6-32.6). HCWs at COVID-19 designated facilities with previous outbreak experience, or HCWs who were trained for dealing with the SARS-CoV-2 outbreak, had significantly higher levels of preparedness and awareness (p<0.001). Association rule mining suggests that nurses and doctors who had a 'great-extent-of-confidence' in handling suspected COVID-19 patients had participated in COVID-19 training courses. Male participants (mean difference = 0.34; 95% CI = 0.22, 0.46; p<0.001) and nurses (mean difference = 0.67; 95% CI = 0.53, 0.81; p<0.001) had higher preparedness scores compared to women participants and doctors. INTERPRETATION: There was an unsurprising high level of awareness and preparedness among HCWs who participated in COVID-19 training courses. However, disparity existed along the lines of gender and type of HCW. It is unknown whether the difference in COVID-19 preparedness that we detected early in the pandemic may have translated into disproportionate SARS-CoV-2 burden of disease by gender or HCW type

    Quantifying antimicrobial access and usage for paediatric diarrhoeal disease in an urban community setting in Asia.

    Get PDF
    OBJECTIVES: Antimicrobial-resistant infections are a major global health issue. Ease of antimicrobial access in developing countries is proposed to be a key driver of the antimicrobial resistance (AMR) epidemic despite a lack of community antimicrobial usage data. METHODS: Using a mixed-methods approach (geospatial mapping, simulated clients, healthcare utilization, longitudinal cohort) we assessed antimicrobial access in the community and quantified antimicrobial usage for childhood diarrhoea in an urban Vietnamese setting. RESULTS: The study area had a pharmacy density of 15.7 pharmacies/km2 (a pharmacy for every 1316 people). Using a simulated client method at pharmacies within the area, we found that 8% (3/37) and 22% (8/37) of outlets sold antimicrobials for paediatric watery and mucoid diarrhoea, respectively. However, despite ease of pharmacy access, the majority of caregivers would choose to take their child to a healthcare facility, with 81% (319/396) and 88% (347/396) of responders selecting a specialized hospital as one of their top three preferences when seeking treatment for watery and mucoid diarrhoea, respectively. We calculated that at least 19% (2688/14427) of diarrhoea episodes in those aged 1 to <5 years would receive an antimicrobial annually; however, antimicrobial usage was almost 10 times greater in hospitals than in the community. CONCLUSIONS: Our data question the impact of community antimicrobial usage on AMR and highlight the need for better education and guidelines for all professionals with the authority to prescribe antimicrobials
    corecore