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The Keap1 protein (Kelch-like ECH-related protein 1) and the Nrf2 transcription factor (NF-E2-related factor 2) are important systems for maintaining homeostasis, redox, and metabolism. Based on the Keap1/Nrf2 pathway, the antioxidative mechanism of P. amarus extract (PAE) was predicted. In this paper, we evaluated the protective effects of PAE on the oxidative toxicity induced by sodium arsenite (NaAsO2) and hydrogen peroxide (H2O2) in zebrafish larvae. We first determined that the LC50 values for NaAsO2, H2O2, and PAE at 3.5 days postfertilization (dpf) were 1 mM, 3 mM, and 200 μg/mL, respectively. Then, to assess the antioxidant effects of P. amarus, 3.5 dpf zebrafish larvae were pretreated with PAE at concentrations of 0, 50, 75, and 100 μg/ml for 12 h, and then the PAE solution was replaced with 1 mM NaAsO2 or 3 mM H2O2 to assess challenge survival within 48 h. Interestingly, all three concentrations, 50, 75, and 100 μg/mL PAE, increased the survival rate of zebrafish larvae compared to those larvae exposed to only 1 mM NaAsO2. Similarly, PAE at concentrations of 75 and 100 μg/mL protected zebrafish larvae after exposure to 3 mM H2O2. Real-time qPCR analysis was performed after 3.5 dpf zebrafish larvae were exposed to 100 μg/mL PAE for 12 h to verify whether the increasing antioxidative activity is depended on the Nrf2 pathway. The expression of the Nrf2 target genes glutathione-S-transferase Pi 1 (gstp1) and peroxidase 1 (prdx1) was assessed using real-time qPCR. However, the expression of this gene was not significantly different between control larvae and PAE-treated larvae. Thus, PAE induces antioxidant activity in zebrafish in a Keap1/Nrf2-independent manner.

This global survey of vAh brought together scientists that study fish disease to evaluate the evolution, geographical distribution, phylogeny, and hosts of vAh and other Aeromonas sp. isolates. In addition to vAh isolates from China and the United States, four new vAh isolates were isolated from the lower Mekong River basin in Cambodia and Vietnam, indicating the significant threat of vAh to modern aquaculture and the need for improved biosecurity to prevent vAh spread.

In this study, TiO2 nanowires on TiO2 nanotubes arrays (TNWs/TNAs) and Au-decorated TNWs/TNAs nanostructures are designed and fabricated as a new type of photoanode for photoelectrochemical (PEC) water splitting. The TNWs/TNAs were fabricated on Ti folds by anodization using an aqueous NH4F/ethylene glycol solution, while Au nanoparticles (NPs) and Au nanorods (NRs) were synthesized by Turkevich methods. We studied the crystal structure, morphology, and PEC activity of four types of nanomaterial photoanodes, including TNWs/TNAs, Au NPs- TNWs/TNAs, Au NRs-TNWs/TNAs, and Au NPs-NRs-TNWs/TNAs. The TiO2 and Au-TiO2 samples exhibited pure anatase phase of TiO2 with (0 0 4), (1 0 1), and (1 0 5) preferred orientations, while Au-TiO2 presented a tiny XRD peak of Au (111) due to a small Au decorated content of 0.7 ± 0.2 at.%. In addition, the samples obtained a well-defined and uniformed structure of TNAs/TNWs; Au NPs (size of 19.0 ± 1.9 nm) and Au NRs (width of 14.8 ± 1.3 nm and length of 99.8 ± 15.1 nm) were primarily deposited on TNWs top layer; sharp Au/TiO2 interfaces were observed from HRTEM images. The photocurrent density (J) of the photoanode nanomaterials was in the range of 0.24–0.4 mA/cm2. Specifically, Au NPs-NRs- decorated TNWs/TNAs attained the highest J value of 0.4 mA/cm2 because the decoration of Au NPs and Au NRs mixture onto TNWs/TNAs improved the light harvesting capability and the light absorption in the visible-infrared region, enhanced photogenerated carriers’ density, and increased electrons’ injection efficiency via the localized surface plasmon resonance (LSPR) effect occurring at the Au nanostructures. Furthermore, amongst the investigated nanophotocatalysts, the Au NPs-NRs TNWs/TNAs exhibited the highest photocatalytic activity in the degradation of methylene blue with a high reaction rate constant of 0.7 ± 0.07 h−1, which was 2.5 times higher than that of the pristine TNWs/TNAs.

We studied the development and persistence of neutralizing antibodies against SARS-CoV-2 ancestral strain, and Delta and Omicron (BA.1 and BA.2) variants in Vietnamese healthcare workers (HCWs) up to 15 weeks after booster vaccination. We included 47 HCWs, including group 1 (G1, N = 21) and group 2 (G2; N = 26) without and with breakthrough Delta variant infection before booster immunization, respectively). The study participants had completed primary immunization with ChAdOx1-S and booster vaccination with BNT162b2. Neutralizing antibodies were measured using a surrogate virus neutralization assay. Of the 21 study participants in G1, neutralizing antibodies against ancestral strain, Delta variant, BA.1, and BA.2 were (almost) abolished at month 8 after the second dose, but all had detectable neutralizing antibodies to the study viruses at week 2 post booster dose. Of the 26 study participants in G2, neutralizing antibody levels to BA.1 and BA.2 were significantly higher than those to the corresponding viruses measured at week 2 post breakthrough infection and before the booster dose. At week 15 post booster vaccination, neutralizing antibodies to BA.1 and BA.2 dropped significantly, with more profound changes observed in those without breakthrough Delta variant infection. Booster vaccination enhanced neutralizing activities against ancestral strain and Delta variant compared with those induced by primary vaccination. These responses were maintained at high levels for at least 15 weeks. Our findings emphasize the importance of the first booster dose in producing cross-neutralizing antibodies against Omicron variant. A second booster to maintain long-term vaccine effectiveness against the currently circulating variants merits further research.

Highlights • Antimicrobial stewardship (AMS) in low- and middle-income settings has multiple players. • Leadership commitment greatly influences AMS implementation in hospitals. • Staff showed good perception of AMS but misperceptions on local resistance levels. • Guidelines on staffing and training standards are needed to support implementation. • More support is needed to promote active roles of pharmacists and microbiologists., Objectives This study aimed to analyse the current state of antimicrobial stewardship (AMS) in hospitals in Viet Nam, a lower-middle income country (LMIC), to identify factors determining success in AMS implementation and associated challenges to inform planning and design of future programmes. Methods We conducted a mixed-methods study in seven acute-care hospitals in the antimicrobial resistance (AMR) surveillance network in Viet Nam. Data collection included 7 focus group discussions, 40 in-depth interviews and a self-administered quantitative survey of staff on AMR and AMS programmes. We summarised qualitative data by reporting the most common themes according to the core AMS elements, and analysed quantitative data using proportions and a linear mixed-effects model. Results The findings reveal a complex picture of factors and actors involved in AMS implementation from the national level to the departmental and individual level within each hospital. The level of implementation varied, starting from the formation of an AMS committee, with or without active delivery of specific interventions. Development of treatment guidelines, pre-authorisation of antimicrobial drug classes, and post-prescription audit and feedback to doctors in selected clinical departments were the main interventions reported. A higher level of leadership support and commitment to AMS led to a higher level of engagement with AMS activities from the AMS team and effective collaboration between departments involved. Conclusion Establishing country-specific guidelines on AMS staffing and adapting standards for AMS education and training from international resources are needed to support capacity building to implement AMS programmes effectively in LMICs such as Viet Nam.

We studied the immunogenicity of the Oxford-AstraZeneca vaccine in health-care workers of a major infectious diseases hospital in Vietnam. We measured neutralizing antibodies before and 14 days after each dose, and at day 28 and month 3 after dose 1. A total of 554 workers (136 men and 418 women; age range, 22–71 years; median age, 36 years) participated with the study. Of the 144 participants selected for follow-up after dose 1, 104 and 94 gave blood for antibody measurement at weeks 6 and 8, and at month 3 after dose 1, respectively. The window time between the two doses was 6 weeks. At baseline, none had detectable neutralizing antibodies. After dose 1, the proportion of participants with detectable neutralizing antibodies increased from 27.3% (151 of 554) at day 14 to 78.0% (432 of 554) at day 28. Age correlated negatively with the development and the levels of neutralizing antibodies. However, at day 28, these differences were less profound, and women had a greater seroconversion rate and greater levels of neutralizing antibodies than men. After dose 2, these age and gender associations were not observable. In addition, the proportion of study participants with detectable neutralizing antibodies increased from 70.2% (73 of 104) before dose 2 (week 6, after dose 1) to 98.1% (102 of 104) 14 days later. At month 3, neutralizing antibodies decreased and 94.7% (89 of 94) of the study participants remained seropositive. The Oxford-AstraZeneca COVID-19 vaccine is immunogenic in Vietnamese health-care workers. These data are critical to informing the deployment of the COVID-19 vaccine in Vietnam and in Southeast Asia, where vaccination coverage remains inadequate.

The synergic effect using γ-irradiation in combination with hydrogen peroxide was applied for preparation of water-soluble and low molecular weight (Mw) β-glucan from yeast water-insoluble β-glucans. The structural characterization by gel permeation chromatography (GPC), Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) suggested that the γ-irradiation did not cause any change in basic structure of β-glucans, except for the reduction in degree of polymerization. The suitable degradation conditions were determined at 10% β-glucans in pH~9% and 1% hydrogen peroxide. The water-soluble oligoβ-glucan with Mw~15 kDa showed a significantly effect on the increase of body weight and survival rate of Penaeus monodon shrimps challenged with Vibrio parahaemolyticus and White spot syndrome virus (WSSV). The oral administration of 15 kDa-oligoβ-glucan with a daily dose of 1000 ppm strongly stimulated immune factors in tested shrimps such as phagocytosis activity (PA), phenoloxidase (PO) and superoxide dismutase (SOD). Furthermore, dietary of 1000 ppm 15 kDa-oligoβ-glucan also significantly up-regulated the gene expressions of lipopolysaccharide and β-1,3-glucan-binding protein (LGLP) and prophenoloxidase (proPO). The relative percent of survivals (RPS) of shrimps fed with 1000 ppm 15 kDa-oligoβ-glucan were 56.2% and 38.1% post the challenge with V. parahaemolyticus and WSSV, respectively. These results demonstrated that the water-soluble oligoβ-glucan with Mw~15 kDa prepared by synergic degradation method showed a very promising potential for application as a natural growth promotor and immunostimulant in shrimp culture.

We studied the immunogenicity of Oxford-AstraZeneca vaccine in Vietnamese healthcare workers. We collected blood samples before each dose, at 14 days after each dose, and month 1 and 3 after dose 1 from each participant alongside demographics data. We measured neutralizing antibodies using a surrogate virus neutralization assay. The 554 study participants (136 males and 418 females) were aged between 22-71 years (median: 36 years). 104 and 94 out of 144 selected participants were successfully followed up at 14 days after dose 2 and 3 months after dose 1, respectively. Neutralizing antibodies increased after each dose, with the sero-conversion rate reaching 98.1% (102/104) at 14 days after dose 2. At month 3 after dose 1, neutralizing antibody levels decreased, while 94.7% (89/94) of the study participants remained seropositive. Oxford-AstraZeneca COVID-19 vaccine is immunogenic in Vietnamese healthcare workers. The requirement for a third dose warrants further research.

Background: Data on breakthrough SARS-CoV-2 Delta variant infections are limited. Methods: We studied breakthrough infections among healthcare workers of a major infectious diseases hospital in Vietnam. We collected demographics, vaccination history and results of PCR diagnosis alongside clinical data. We measured SARS-CoV-2 (neutralizing) antibodies at diagnosis, and at week 1, 2 and 3 after diagnosis. We sequenced the viruses using ARTIC protocol. Findings: Between 11th–25th June 2021 (week 7–8 after dose 2), 69 healthcare workers were tested positive for SARS-CoV-2. 62 participated in the clinical study. 49 were (pre)symptomatic with one requiring oxygen supplementation. All recovered uneventfully. 23 complete-genome sequences were obtained. They all belonged to the Delta variant, and were phylogenetically distinct from the contemporary Delta variant sequences obtained from community transmission cases, suggestive of ongoing transmission between the workers. Viral loads of breakthrough Delta variant infection cases were 251 times higher than those of cases infected with old strains detected between March-April 2020. Time from diagnosis to PCR negative was 8–33 days (median: 21). Neutralizing antibody levels after vaccination and at diagnosis of the cases were lower than those in the matched uninfected controls. There was no correlation between vaccine-induced neutralizing antibody levels and viral loads or the development of symptoms. Interpretation: Breakthrough Delta variant infections are associated with high viral loads, prolonged PCR positivity, and low levels of vaccine-induced neutralizing antibodies, explaining the transmission between the vaccinated people. Physical distancing measures remain critical to reduce SARS-CoV-2 Delta variant transmission. Funding: Wellcome (106680/B/14/Z and 204904/Z/16/Z). Declaration of Interest: None to declare. Ethical Approval: The study was approved by the Institutional Review Board of HTD and the Oxford Tropical Research Ethics Committee, University of Oxford, UK.

ObjectivesTo investigate the feasibility of establishing hospital-based antimicrobial stewardship (AMS) programmes comprising action-planning, educational interventions and data feedback in two provincial-level hospitals in Viet Nam.Design and settingThis was an implementation research using participatory action process and existing resources from the Duke Antimicrobial Stewardship Outreach Network with local adjustments. A national stakeholder meeting and Strengths-Weaknesses-Opportunities-Threats (SWOT) analysis were conducted to identify gaps and potential interventions.ParticipantsHospital AMS staff implemented activities throughout the study phases. Routinely collected patient data were analysed to support planning, implementation and evaluation.InterventionsHospitals were considered as a complex adaptive system and leveraged their unique characteristics and interconnections to develop 1-year plans containing core interventions (data use, educational training, prospective audit with feedback (PAF) and evaluations).Outcome measuresWe assessed feasibility using outputs from stakeholder meeting, SWOT analysis, baseline data, planning process and implementation.ResultsThe stakeholder meeting identified three gaps for AMS at national level: supportive policies, AMS training and core competencies and collaboration. At the hospitals, AMS programmes took 1 year for planning due to lack of hospital-specific procedures and relevant staff competencies. Baseline data (January–December 2019) showed variations in antibiotic consumption: 951 days of therapy (DOT) per 1000 days present in the control and 496 in the intervention wards in hospital 1, and 737 and 714 in hospital 2, respectively. During 1-year implementation, clinical pharmacists audited 1890 antibiotic prescriptions in hospital 1 (June 2020–May 2021) and 1628 in hospital 2 (July 2020–July 2021), and will continue PAF in their daily work.ConclusionOur data confirmed the need to contextualise AMS programmes in low-income and middle-income countries (LMICs) and demonstrated the usefulness of implementation research design in assessing programme feasibility. Developing staff competencies, using local data to stimulate actions and integrating programme activities in routine hospital work are key to success in LMICs.

As of 13 July 2016, 13 countries have reported fetal Zika virus (ZIKV) infection. Here we report a case of fetal ZIKV infection that resulted from an infection originating in Vietnam.

In this study, silica was synthesized from rice husk ash (RHA-SiO2) by precipitation method. Graphene oxide (GO) was prepared by modified Hummers method. RHA-SiO2/GO nanocomposite was fabricated by in-situ one-step method using 3-Aminopropyltriethoxysilane (APS) as a coupling agent. The nanocomposite was characterized by using X-ray Fluorescence, X-ray diffraction, transmission electron microscopy, Fourier transform infrared spectroscopy, Raman spectroscopy, and Brunauer-Emmett-Teller (BET) specific surface area. The adsorption of RHA-SiO2/GO for Ni2+ ions from water was investigated and compared with the precursors. Ultraviolet–visible (UV-Vis) spectroscopy was used to quantify the amount of the initial and the residual Ni2+ concentration. The maximum adsorption capacity of the nanocomposite for Ni2+ calculated from Langmuir isotherm model, which was 256.4 mg/g. In addition, the adsorption data were well–fitted to the pseudo–second–order kinetic equation. Accordingly, this study demonstrated that RHA-SiO2/GO could be used as a highly efficient adsorbent for removal Ni2+ ions from aqueous solution.In this study, silica was synthesized from rice husk ash (RHA-SiO2) by precipitation method. Graphene oxide (GO) was prepared by modified Hummers method. RHA-SiO2/GO nanocomposite was fabricated by in-situ one-step method using 3-Aminopropyltriethoxysilane (APS) as a coupling agent. The nanocomposite was characterized by using X-ray Fluorescence, X-ray diffraction, transmission electron microscopy, Fourier transform infrared spectroscopy, Raman spectroscopy, and Brunauer-Emmett-Teller (BET) specific surface area. The adsorption of RHA-SiO2/GO for Ni2+ ions from water was investigated and compared with the precursors. Ultraviolet–visible (UV-Vis) spectroscopy was used to quantify the amount of the initial and the residual Ni2+ concentration. The maximum adsorption capacity of the nanocomposite for Ni2+ calculated from Langmuir isotherm model, which was 256.4 mg/g. In addition, the adsorption data were well–fitted to the pseudo–second–order kinetic equation. Accordingly, this study demonstrated that RHA-SiO...

There are four dengue virus serotypes, based on molecular analysis. Each serotype is divided to several different genotypes, such as there are 5 genotypes in dengue virus serotype 3 (DENV-3), in which genotype II was confirmed to be the main etiology cause the big dengue fever/dengue hemorrhagic fever outbreak in Vietnam 1998. Molecular epidemiological study was carried out on DENV-3, which causing dengue fever/dengue hemorrhagic fever in some epidemic areas with high morbidity and mortality from southern Vietnam in 2010. In this study, viral RNA of DENV-3 were extracted directly from dengue fever/dengue hemorrhagic fever patient sera, typing by RT-PCR (reverse transcriptase-polymerase chain reaction) with Lanciotti specific primers, sequencing the entire envelope (E) gene and comparative analysis with DENV-3 strain isolated from the big outbreak of dengue hemorrhagic fever in whole country in 1998. The phylogenetic analysis of DENV-3 from Vietnam as well as previously published strains, the results showed that: Vietnamese DENV-3 belong to genotype II among 5 genotypes classified for worldwide DENV-3 and have been closely related to Thailand isolates. Further researchs need to be carried out in order to confirm the evidence for local genetic evolution and conserved functional structure of E protein of DENV-3.