Chemical diversity of essential oils of rhizomes of six species of Zingiberaceae family

In this study, the essential oils from the rhizomes of six species belonging to the Zingiberaceae family, including Zingiber zerumbet, Curcuma pierreana, Globba macrocarpa, Alpinia conchigera, Stahlianthus campanulatus and Amomum sp., collected in Binh Chau-Phuoc Buu Nature Reserve were isolated using hydrodistillation, and their constituents were identified via Gas Chromatography-Mass Spectrometry. A total of 91 constituents have been identified from essential oils. These compounds were classified into 4 clusters by Agglomerative Hierarchical Clustering (AHC) and Principal Component Analysis (PCA) analysis. The principal constituents of the essential oils isolated from four species, C. pierreana, S. campanulatus, A. conchigera, and Z. zerumbet contained camphene (18.82%), α-copaene (11.75%), p-xylene (21.86%), and α-santalene (17.91%), which were significantly different from those in previous reports. Furthermore, this study revealed the chemical constituents of essential oils of G. macrocarpa and Amomum sp. for the first time. Accordingly, artemisia triene (22.21%), β-pinene (13.57%), 4,6,8-trimethylazulene (11.1%), 2-tert-butylquinoline (9.86%), β-patchoulene (7.06%), α-elemene (6.93%), and β-ocimene (6.0%) were the major compounds in essential oils of G. macrocarpa rhizomes whereas the oil of Amomum sp. was found to be rich in 2-carene (21.82%), fenchyl acetate (14.26%), 3-carene (8.28%), bornyl acetate (7.7%), and D-limonene (7.13%)

THE RELATIONSHIPS BETWEEN STUDENTS’ SELF-CONFIDENCE AND THEIR ENGLISH-SPEAKING PERFORMANCE: A CASE STUDY OF ENGLISH-MAJORED STUDENTS AT A PRIVATE UNIVERSITY IN VIETNAM

This research aimed to discover the relationships between students' self-confidence and their English-speaking performance. In our research, self-confidence was divided into three components which are affective confidence, behavioral confidence, and cognitive confidence. In addition, speaking performance included eight components which are vocabulary, grammar, pronunciation, fluency, coherence, comprehension, task, and content. A sample of 150 English-majored students at a university in Vietnam was surveyed in this study by using a convenience sampling technique, and then conducting semi-structured interviews to seek for qualitative information from 10 participants out of 150. The result from our study showed that there are significant relationships between the two variables. The more confident the students are, the more accomplished they would be in the presenting procedure since they have superior cognition and understand how to modify their learning methods to build a comprehensive individual in learning English language. We expect that these findings can help students adjust their learning methods to improve their self-confidence as well as English speaking performance and by that way, universities can add more speaking-related subjects so that students can have more opportunities to speak and learn more speaking skills.  Article visualizations

Risk Factors for Human Infection with Avian Influenza A H5N1, Vietnam, 2004

TOC Summary: Risk factors include direct or household contact with sick or dead poultry and absence of an indoor water source

SECURE PERFORMANCE ANALYSIS OF ADAPTIVE ENERGY HARVESTING ENABLED RELAYING NETWORKS

In this paper, the impact of the jamming signal on the secrecy performance of Energy Harvesting (EH) enabled dual-hop amplify-and-forward relaying network is investigated. First, the security outage probability analysis is studied for conventional networks under a single passive eavesdropper attack. Then, the outage performance analysis in two cases regarding energy harvesting is investigated. Moreover, the proposed work enhances Physical Layer (PHY) security performance of two-hop relaying model using Cooperative Jamming Dual-Hop Techniques (CJDH). For this purpose, new closed-form expressions are derived for the outage probability of CJDH model in the presence of interference over Rayleigh fading channels. A power allocation optimization problem for energy harvesting protocol is formulated and solved for enhancing the system security. The derived analytical formulas herein are supported by numerical and simulation results to clarify the main contributions of the paper

A multi locus sequence analysis scheme for phylogeny of the Bacillus subtilis species complex and its advantages over 16S rRNA genes

A multi locus sequence analysis (MLSA approach) was studied on the Bacillus genus, or the Bacillus subtilis species complex for specific, including 08 strains from four species (B. subtilis, B. pumilus, B. licheniformis and B. amyloliquefaciens) were provided by Biotechnology Center of Ho Chi Minh City. The research was based on sequences of 16S rRNA genes, the concatenation of five protein-coding housekeeping genes: glpF, pta, purH, pycA, and rpoD. After PCR amplification and sequencing the phylogenetic tree of 16S rRNA sequences, concatenate sequences (as well as the phylogenetic tree of each housekeeping gene) are constructed for comparison and discussion. The aim of this study is reach for better resolution and differentiation of strains and species within the B. subtilis species and to determine whether MLSA scheme show advantages in 16S rRNA gene-based studies

Targeted sequencing from cerebrospinal fluid for rapid identification of drug-resistant tuberculous meningitis

Mortality from tuberculous meningitis (TBM) remains around 30%, with most deaths occurring within 2 months of starting treatment. Mortality from drug-resistant strains is higher still, making early detection of drug resistance (DR) essential. Targeted next-generation sequencing (tNGS) produces high read depths, allowing the detection of DR-associated alleles with low frequencies. We applied Deeplex Myc-TB-a tNGS assay-to cerebrospinal fluid (CSF) samples from 72 adults with microbiologically confirmed TBM and compared its genomic drug susceptibility predictions to a composite reference standard of phenotypic susceptibility testing (pDST) and whole genome sequencing, as well as to clinical outcomes. Deeplex detected Mycobacterium tuberculosis complex DNA in 24/72 (33.3%) CSF samples and generated full DR reports for 22/24 (91.7%). The read depth generated by Deeplex correlated with semi-quantitative results from MTB/RIF Xpert. Alleles with <20% frequency were seen at canonical loci associated with first-line DR. Disregarding these low-frequency alleles, Deeplex had 100% concordance with the composite reference standard for all drugs except pyrazinamide and streptomycin. Three patients had positive CSF cultures after 30 days of treatment; reference tests and Deeplex identified isoniazid resistance in two, and Deeplex alone identified low-frequency rifampin resistance alleles in one. Five patients died, of whom one had pDST-identified pyrazinamide resistance. tNGS on CSF can rapidly and accurately detect drug-resistant TBM, but its application is limited to those with higher bacterial loads. In those with lower bacterial burdens, alternative approaches need to be developed for both diagnosis and resistance detection

Rifampicin resistant 'Mycobacterium tuberculosis' in Vietnam, 2020–2022

Objective: We conducted a descriptive analysis of multi-drug resistant tuberculosis (MDR-TB) in Vietnam’s two largest cities, Hanoi and Ho Chi Minh city. Methods: All patients with rifampicin resistant tuberculosis were recruited from Hanoi and surrounding provinces between 2020 and 2022. Additional patients were recruited from Ho Chi Minh city over the same time period. Demographic data were recorded from all patients, and samples collected, cultured, whole genome sequenced and analysed for drug resistance mutations. Genomic susceptibility predictions were made on the basis of the World Health Organization’s catalogue of mutations in Mycobacterium tuberculosis associated with drug resistance, version 2. Comparisons were made against phenotypic drug susceptibility test results where these were available. Multivariable logistic regression was used to assess risk factors for previous episodes of tuberculosis. Results: 233/265 sequenced isolates were of sufficient quality for analysis, 146 (63 %) from Ho Chi Minh City and 87 (37 %) from Hanoi. 198 (85 %) were lineage 2, 20 (9 %) were lineage 4, and 15 (6 %) were lineage 1. 17/211 (8 %) for whom HIV status was known were infected, and 109/214 (51 %) patients had had a previous episode of tuberculosis. The main risk factor for a previous episode was HIV infection (odds ratio 5.1 (95 % confidence interval 1.3–20.0); p = 0.021). Sensitivity for predicting first-line drug resistance from whole genome sequencing data was over 90 %, with the exception of pyrazinamide (85 %). For moxifloxacin and amikacin it was 50 % or less. Among rifampicin-resistant isolates, prevalence of resistance to each non-first-line drug was < 20 %. Conclusions: Drug resistance among most MDR-TB strains in Vietnam’s two largest cities is confined largely to first-line drugs. Living with HIV is the main risk factor among patients with MDR-TB for having had a previous episode of tuberculosis

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

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

The influence of human genetic variation on early transcriptional responses and protective immunity following immunization with Rotarix vaccine in infants in Ho Chi Minh City in Vietnam : a study protocol for an open single-arm interventional trial [awaiting peer review]

Background: Rotavirus (RoV) remains the leading cause of acute gastroenteritis in infants and children aged under five years in both high- and low-middle-income countries (LMICs). In LMICs, RoV infections are associated with substantial mortality. Two RoV vaccines (Rotarix and Rotateq) are widely available for use in infants, both of which have been shown to be highly efficacious in Europe and North America. However, for unknown reasons, these RoV vaccines have markedly lower efficacy in LMICs. We hypothesize that poor RoV vaccine efficacy across in certain regions may be associated with genetic heritability or gene expression in the human host. Methods/design: We designed an open-label single-arm interventional trial with the Rotarix RoV vaccine to identify genetic and transcriptomic markers associated with generating a protective immune response against RoV. Overall, 1,000 infants will be recruited prior to Expanded Program on Immunization (EPI) vaccinations at two months of age and vaccinated with oral Rotarix vaccine at two and three months, after which the infants will be followed-up for diarrheal disease until 18 months of age. Blood sampling for genetics, transcriptomics, and immunological analysis will be conducted before each Rotarix vaccination, 2-3 days post-vaccination, and at each follow-up visit (i.e. 6, 12 and 18 months of age). Stool samples will be collected during each diarrheal episode to identify RoV infection. The primary outcome will be Rotarix vaccine failure events (i.e. symptomatic RoV infection despite vaccination), secondary outcomes will be antibody responses and genotypic characterization of the infection virus in Rotarix failure events. Discussion: This study will be the largest and best powered study of its kind to be conducted to date in infants, and will be critical for our understanding of RoV immunity, human genetics in the Vietnam population, and mechanisms determining RoV vaccine-mediated protection. Registration: ClinicalTrials.gov, ID: NCT03587389. Registered on 16 July 2018

Safety and efficacy of fluoxetine on functional outcome after acute stroke (AFFINITY): a randomised, double-blind, placebo-controlled trial

Background 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. Methods 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. Findings 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. Interpretation 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