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.
A second cluster of COVID-19 cases imported from Europe occured in Vietnam from early March 2020. We describe 44 SARS-CoV-2 RT-PCR positive patients (cycle threshold value <30) admitted to the ...National Hospital for Tropical Diseases in Hanoi between March 6 and April 15 2020. Whole SARS-CoV-2 genomes from these patients were sequenced using Illumina Miseq and analysed for common genetic variants and relationships to local and globally circulating strains. Results showed that 32 cases were Vietnamese with a median age of 37 years (range 15-74 years), and 23 were male. Most cases were acquired outside Vietnam, mainly from the UK (n = 15), other European countries (n = 14), Russia (n = 6) and countries in Asia (n = 3). No cases had travelled from China. Forty-one cases had symptoms at admission, typically dry cough (n = 36), fever (n = 20), sore throat (n = 14) and diarrhoea (n = 12). Hospitalisation was long with a median of 25 days, most commonly from 20-29 days. All SARS-CoV-2 genomes were similar (92-100% sequence homology) to the reference sequence Wuhan_1 (NC_045512), and 32 strains belonged to the B.1.1 lineage. The three most common variants were linked, and included C3037T, C14408T (nsp12: P323L) and A23403G (S: D614G) mutations. This group of mutations often accompanied variant C241T (39/44 genomes) or GGG 28881..28883 AAC (33/44 genomes). The prevalence of the former reflected probable European origin of viruses, and the transition D614G was dominant in Vietnam. New variants were identified; however, none could be associated with disease severity.
In recent years, serosurveillance has gained momentum as a way of determining disease transmission and immunity in populations, particularly with respect to vaccine-preventable diseases. At the end ...of 2017, the Oxford University Clinical Research Unit and the National Institute of Hygiene and Epidemiology held a meeting in Vietnam with national policy makers, researchers, and international experts to discuss current seroepidemiologic projects in Vietnam and future needs and plans for nationwide serosurveillance. This report summarizes the meeting and the plans that were discussed to set up nationwide serosurveillance in Vietnam.
In this study, titanium (Ti) was used as an active dopant to incorporate into BiVO4 lattice using the hydrothermal method. The synthesized BiVO4 and Ti–BiVO4 with 1, 5 and 10 wt% of Ti dopants have ...been applied for photocatalytic decomposition of Tetracycline under visible light irradiation. The characterized results showed that this synthesized BiVO4 and Ti–BiVO4 materials existed in a form of spherical particles. The particle sizes of the Ti–BiVO4 were much bigger than that of the BiVO4. However, Ti dopants effectively enhanced visible light absorption, decreased band gap energy as well as prevented electron-hole recombination of the BiVO4 leading to increase in photocatalytic activities of the doped materials. The obtained results from photocatalytic experiments indicated that the 5Ti–BiVO4, whose weight ratio of Ti was 5%, was the best material for TC degradation (78.49%). Recycling tests were consecutively carried out in 4 runs to demonstrate the stability of the BiVO4 photocatalyst with 5 wt% of Ti dopant.
Abstract The first nationwide outbreak of COVID-19 in Vietnam started in late April 2021 and was caused almost exclusively by a single Delta lineage, AY.57. In early 2022, multiple Omicron variants ...co-circulated with Delta variants and quickly became dominant. The co-circulation of Delta and Omicron happened leading to possibility of co-infection and recombination events which can be revealed by viral genomic data. From January to October 2022, a total of 1028 viral RNA samples out of 4852 positive samples (Ct < 30) were sequenced by the long pooled amplicons method on Illumina platforms. All sequencing data was analysed by the workflow for SARS-CoV-2 on CLC genomics workbench and Illumina Dragen Covid application. Among those sequenced samples, we detected a case of Delta AY.57/Omicron BA.1 co-infection and two cases of infection with Delta AY.57/Omicron BA.2 recombinants which were nearly identical and had different epidemiological characteristics. Since the AY.57 lineage circulated almost exclusively in Vietnam, these results strongly suggest domestic events of co-infection and recombination. These findings highlight the strengths of genomic surveillance in monitoring the circulating variants in the community enabling rapid identification of viral changes that may affect viral properties and evolutionary events.
ABSTRACT This study was conducted to examine the effects of dietary replacement of fish meal (FM) by raw soybean residue (SR) and fermented soybean residue (FSR) on growth performance, biological ...parameters and nutrient apparent digestibility coefficients (ADCs) of red tilapia (Oreochromis sp.). FSR was obtained by fermenting SR with Bacillus subtilis V37. Five isonitrogenous and isoenergetic diets were formulated to replace 35% or 50% of FM by SR or FSR. The diets were denoted as follows: FMD, SR35D, FSR35D, SR50D, and FSR50D. The FMD (the reference diet) contained FM as a main source of dietary protein. A total of 300 fingerling red tilapia with an initial body weight (BW) of 13.7 g were randomly distributed into 15 tanks (20 fish/tank, 3 tanks/dietary treatment) and fed the experimental diets twice daily, for 8 weeks. Results showed that fish fed SR35D and SR50D had significantly lower final BW, weight gain (WG) and specific growth rate (SGR), but higher feed conversion ratio (FCR), than fish fed FMD (P < 0.05). Meanwhile, no significant differences in growth performance and feed utilization between the FSR35D and FMD groups were detected. Fish fed FSR-included diets showed significantly better growth performance and FCR than those fed SR-included diets (P < 0.05). Feeding the fish with SR35D and SR50D reduced digestive enzyme activity, bile juice secretion, and nutrient ADCs. These parameters of the experimental fish were markedly improved by feeding with FSR35D and FSR50D, and no statistical differences were observed between FSR35D-and FMD-fed fish. The results of the current study indicated that SR interfered with digestive enzyme activity, bile juice secretion, nutrient ADCs, and growth and feed performances. The enhancements of these parameters in fish fed FSR-included diets suggested that fermentation of SR with Bacillus subtilis V37 benefited digestive physiology, growth performance and feed utilization of red tilapia fed soybean protein-based diets.
Trials of fluoxetine for recovery after stroke report conflicting results. The Assessment oF FluoxetINe In sTroke recoverY (AFFINITY) trial aimed to show if daily oral fluoxetine for 6 months after ...stroke improves functional outcome in an ethnically diverse population.
AFFINITY was a randomised, parallel-group, double-blind, placebo-controlled trial done in 43 hospital stroke units in Australia (n=29), New Zealand (four), and Vietnam (ten). Eligible patients were adults (aged ≥18 years) with a clinical diagnosis of acute stroke in the previous 2–15 days, brain imaging consistent with ischaemic or haemorrhagic stroke, and a persisting neurological deficit that produced a modified Rankin Scale (mRS) score of 1 or more. Patients were randomly assigned 1:1 via a web-based system using a minimisation algorithm to once daily, oral fluoxetine 20 mg capsules or matching placebo for 6 months. Patients, carers, investigators, and outcome assessors were masked to the treatment allocation. The primary outcome was functional status, measured by the mRS, at 6 months. The primary analysis was an ordinal logistic regression of the mRS at 6 months, adjusted for minimisation variables. Primary and safety analyses were done according to the patient's treatment allocation. The trial is registered with the Australian New Zealand Clinical Trials Registry, ACTRN12611000774921.
Between Jan 11, 2013, and June 30, 2019, 1280 patients were recruited in Australia (n=532), New Zealand (n=42), and Vietnam (n=706), of whom 642 were randomly assigned to fluoxetine and 638 were randomly assigned to placebo. Mean duration of trial treatment was 167 days (SD 48·1). At 6 months, mRS data were available in 624 (97%) patients in the fluoxetine group and 632 (99%) in the placebo group. The distribution of mRS categories was similar in the fluoxetine and placebo groups (adjusted common odds ratio 0·94, 95% CI 0·76–1·15; p=0·53). Compared with patients in the placebo group, patients in the fluoxetine group had more falls (20 3% vs seven 1%; p=0·018), bone fractures (19 3% vs six 1%; p=0·014), and epileptic seizures (ten 2% vs two <1%; p=0·038) at 6 months.
Oral fluoxetine 20 mg daily for 6 months after acute stroke did not improve functional outcome and increased the risk of falls, bone fractures, and epileptic seizures. These results do not support the use of fluoxetine to improve functional outcome after stroke.
National Health and Medical Research Council of Australia.
•Plasma technology is introduced to synthesize Pt/WO3.•Pt nanocrystals are homogeneously distributed on the WO3 surface.•The Pt/WO3 nanohybrid processed high catalytic activity.•Dye-sensitized solar ...cells fabricated with Pt/WO3 shows 8.10% efficiency.
In this study, the synthesis of micro-wheels composed of self-assembled tungsten oxide nanorods supported platinum (WO3/Pt) by atmospheric plasma reduction and its application in a counter electrode (CE) for highly efficient dye-sensitized solar cells were discussed. To characterize the developed materials, we conducted SEM, TEM, EDS-TEM, XRD. Due to a large surface-active area of developed material and its support for Pt nanoparticles in diameters of 2–3 nm, the WO3/Pt electrode indicated as a greater electrochemical catalyst for the redox reaction than Pt and WO3 CEs. Thus, the power conversion efficiency for a device with WO3/Pt electrode is improved to 8.10%, compared to 4.36% for a device with WO3 electrode and 7.61% for a cell with a Pt electrode. This study also supplies a procedure for fabricating highly catalytic and low-price catalyst materials for CEs, which has a tremendous meaning for various applications of micro-wheels consisted of self-assembled WO3 nanorods integrated with platinum.
Interpreting point-of-care lung ultrasound (LUS) images from intensive care unit (ICU) patients can be challenging, especially in low- and middle- income countries (LMICs) where there is limited ...training available. Despite recent advances in the use of Artificial Intelligence (AI) to automate many ultrasound imaging analysis tasks, no AI-enabled LUS solutions have been proven to be clinically useful in ICUs, and specifically in LMICs. Therefore, we developed an AI solution that assists LUS practitioners and assessed its usefulness in a low resource ICU.
This was a three-phase prospective study. In the first phase, the performance of four different clinical user groups in interpreting LUS clips was assessed. In the second phase, the performance of 57 non-expert clinicians with and without the aid of a bespoke AI tool for LUS interpretation was assessed in retrospective offline clips. In the third phase, we conducted a prospective study in the ICU where 14 clinicians were asked to carry out LUS examinations in 7 patients with and without our AI tool and we interviewed the clinicians regarding the usability of the AI tool.
The average accuracy of beginners' LUS interpretation was 68.7% 95% CI 66.8-70.7% compared to 72.2% 95% CI 70.0-75.6% in intermediate, and 73.4% 95% CI 62.2-87.8% in advanced users. Experts had an average accuracy of 95.0% 95% CI 88.2-100.0%, which was significantly better than beginners, intermediate and advanced users (p < 0.001). When supported by our AI tool for interpreting retrospectively acquired clips, the non-expert clinicians improved their performance from an average of 68.9% 95% CI 65.6-73.9% to 82.9% 95% CI 79.1-86.7%, (p < 0.001). In prospective real-time testing, non-expert clinicians improved their baseline performance from 68.1% 95% CI 57.9-78.2% to 93.4% 95% CI 89.0-97.8%, (p < 0.001) when using our AI tool. The time-to-interpret clips improved from a median of 12.1 s (IQR 8.5-20.6) to 5.0 s (IQR 3.5-8.8), (p < 0.001) and clinicians' median confidence level improved from 3 out of 4 to 4 out of 4 when using our AI tool.
AI-assisted LUS can help non-expert clinicians in an LMIC ICU improve their performance in interpreting LUS features more accurately, more quickly and more confidently.
•Vitamin B6 and Mg were simultaneously determined by CE-C4D.•Vitamin B6 and Mg peaks were well separated within < 10 min.•A simple and reliable method was developed for pharmaceutical/nutraceutical ...samples.•Single-run CE-C4D analysis can replace HPLC and ICP-OES conventional methods.•Acceptable agreement between measured/label claim contents was achieved.
Vitamins and minerals are usually incorporated in pharmaceutical and nutraceutical products, but a simple, rapid, and inexpensive analytical method for their simultaneous determination is still lacking. In this study, we developed a quantification method for pyridoxine (vitamin B6) and magnesium (Mg) by using purpose-made capillary electrophoresis with capacitively coupled contactless conductivity detection (CE-C4D) instrument. Main analytical conditions include: fused silica capillary (total length 55 cm, effective length 40 cm, inner diameter 50 μm); background electrolyte consisted of 10 mM L-arginine/acetic acid (pH 5) with 20% acetonitrile; separation voltage + 20 kV; hydrodynamic injection (siphoning at 20 cm in 25 s). Detection limits of vitamin B6 and Mg were 1 and 0.1 mg/L, respectively. Good linearity (R2 > 0.999) was observed for vitamin B6 and Mg calibration curves over concentration ranges of 3–100 and 0.3–200 mg/L, respectively. The method was applied to analyze vitamin B6 and Mg in several pharmaceutical and nutraceutical samples. The analytical results obtained by our method were in good agreement with reference methods (i.e., HPLC for vitamin B6 and ICP-OES for Mg). High-efficient and low-cost CE-C4D method can accordingly serve as a promising tool for concurrent analysis of inorganic and organic species in pharmaceutical and nutraceutical analysis.
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