Magneto-transport properties of monolayer borophene in perpendicular magnetic field: influence of electron-phonon interaction

The magneto-transport properties of a borophene monolayer in a perpendicular magnetic field B are studied via calculating the conductivity tensor and resistance under electron-optical phonon interaction by using the linear response theory. Numerical results are obtained and discussed for some specific parameters. The magnetic field-dependent longitudinal conductivity shows the magneto-phonon resonance effect that describes the transition of electrons between Landau levels by absorbing/emitting an optical phonon. The Hall conductivity increases first and then decreases with the magnetic field strength. Also, the longitudinal resistance increases significantly with increasing temperature, which shows the metal behaviour of the material. Practically, the observed magneto-phonon resonance can be applied to experimentally determine some material parameters, such as the distance between Landau levels and the optical phonon energy

Evaluation of Three Adolescent Sexual Health Programs in Ha Noi and Khanh Hoa Province, Vietnam

With an increase in sexual activity among young adults in Vietnam and associated risks, there is a need for evidence-based sexual health interventions. This evaluation of three sexual health programs based on the Protection Motivation Theory (PMT) was conducted in 12 communes in Ha Noi, Nha Trang City, and Ninh Hoa District. Inclusion criteria included unmarried youth 15–20 years residing in selected communes. Communes were randomly allocated to an intervention, and participants were randomly selected within each commune. The intervention programs included Vietnamese Focus on Kids (VFOK), the gender-based program Exploring the World of Adolescents (EWA), and EWA plus parental and health provider education (EWA+). Programs were delivered over a ten-week period in the communities by locally trained facilitators. The gender-based EWA program with parental involvement (EWA+) compared to VFOK showed significantly greater increase in knowledge. EWA+ in comparison to VFOK also showed significant decrease at immediate postintervention for intention to have sex. Sustained changes are observed in all three interventions for self-efficacy condom use, self-efficacy abstinence, response efficacy for condoms, extrinsic rewards, and perceived vulnerability for HIV. These findings suggest that theory-based community programs contribute to sustained changes in knowledge and attitudes regarding sexual risk among Vietnamese adolescents

Hydrogen Chemisorption on Doubly Vanadium Doped Aluminum Clusters

Producción CientíficaThe interaction of hydrogen with doubly vanadium doped aluminum clusters, AlnV2+ (n = 1–12), is studied experimentally by time-of-flight mass spectrometry and infrared multiple photon dissociation spectroscopy. The hydrogen binding geometry is inferred from comparison with infrared spectra predicted by density functional theory and shows that for the more reactive clusters the hydrogen adsorbs dissociatively. Three sizes, n = 4, 5 and 7, are remarkably unreactive compared to the other clusters. For larger sizes the reactivity decreases, a behavior that is similar to that of singly vanadium doped aluminum clusters, and that might be attributed to geometric and/or electronic shielding of the dopants. By examining the electronic structure of Al6V2+ and Al7V2+, interactions between the frontier orbitals of the clusters and those of H2 that explain the size-dependent reactivity are identified.Ministerio de Economía, Industria y Competitividad (Project RYC-2014-15261

Portable Rabies Virus Sequencing in Canine Rabies Endemic Countries Using the Oxford Nanopore MinION

As countries with endemic canine rabies progress towards elimination by 2030, it will become necessary to employ techniques to help plan, monitor, and confirm canine rabies elimination. Sequencing can provide critical information to inform control and vaccination strategies by identifying genetically distinct virus variants that may have different host reservoir species or geographic distributions. However, many rabies testing laboratories lack the resources or expertise for sequencing, especially in remote or rural areas where human rabies deaths are highest. We developed a low-cost, high throughput rabies virus sequencing method using the Oxford Nanopore MinION portable sequencer. A total of 259 sequences were generated from diverse rabies virus isolates in public health laboratories lacking rabies virus sequencing capacity in Guatemala, India, Kenya, and Vietnam. Phylogenetic analysis provided valuable insight into rabies virus diversity and distribution in these countries and identified a new rabies virus lineage in Kenya, the first published canine rabies virus sequence from Guatemala, evidence of rabies spread across an international border in Vietnam, and importation of a rabid dog into a state working to become rabies-free in India. Taken together, our evaluation highlights the MinION’s potential for low-cost, high volume sequencing of pathogens in locations with limited resources

Establishing and validating noninvasive prenatal testing procedure for fetal aneuploidies in Vietnam

Noninvasive prenatal testing (NIPT) for fetal aneuploidies has been widely adopted in developed countries. Despite the sharp decrease in the cost of massively parallel sequencing, the technical know-how and skilled personnel are still one of the major limiting factors for applying this technology to NIPT in low-income settings. Here, we present the establishment and validation of our NIPT procedure called triSure for detection of fetal aneuploidies.We established the triSure algorithm based on the difference in proportion of fetal and maternal fragments from the target chromosome to all chromosomes. Our algorithm was validated using a published data set and an in-house data set obtained from high-risk pregnant women in Vietnam who have undergone amniotic testing. Several other aneuploidy calling methods were also applied to the same data set to benchmark triSure performance.The triSure algorithm showed similar accuracy to size-based method when comparing them using published data set. Using our in-house data set from 130 consecutive samples, we showed that triSure correctly identified the most samples (overall sensitivity and specificity of 0.983 and 0.986, respectively) compared to other methods tested including count-based, sized-based, RAPIDR and NIPTeR.We have demonstrated that our triSure NIPT procedure can be applied to pregnant women in low-income settings such as Vietnam, providing low-risk screening option to reduce the need for invasive diagnostic tests

Tidal amplification and salt intrusion in the Mekong Delta driven by anthrogenic sediment starvation

Natural resources of the Mekong River are essential to livelihood of tens of millions of people. Previous studies highlighted that upstream hydro-infrastructure developments impact flow regime, sediment and nutrient transport, bed and bank stability, fish productivity, biodiversity and biology of the basin. Here, we show that tidal amplification and saline water intrusion in the Mekong Delta develop with alarming paces. While offshore M2 tidal amplitude increases by 1.2–2 mm yr−1 due to sea level rise, tidal amplitude within the delta is increasing by 2 cm yr−1 and salinity in the channels is increasing by 0.2–0.5 PSU yr−1. We relate these changes to 2–3 m bed level incisions in response to sediment starvation, caused by reduced upstream sediment supply and downstream sand mining, which seems to be four times more than previous estimates. The observed trends cannot be explained by deeper channels due to relative sea level rise; while climate change poses grave natural hazards in the coming decades, anthropogenic forces drive short-term trends that already outstrip climate change effects. Considering the detrimental trends identified, it is imperative that the Mekong basin governments converge to effective transboundary management of the natural resources, before irreversible damage is made to the Mekong and its population

Community-led HIV testing services including HIV self-testing and assisted partner notification services in Vietnam: lessons from a pilot study in a concentrated epidemic setting.

INTRODUCTION: The HIV epidemic in Vietnam is concentrated in key populations and their partners - people who inject drugs, men who have sex with men, sex workers and partners of people living with HIV. These groups have poor access to and uptake of conventional HIV testing services (HTS). To address this gap, lay provider- and self-testing and assisted partner notification (aPN) were introduced and delivered by the community. We explored the feasibility and effectiveness of implementing aPN as part of community testing services for key populations. METHODS: Lay provider testing and self-testing was started in January 2017, and targeted key populations and their partners. Since July 2017, aPN was introduced. HTS was offered at drop-in houses or coffee shops in Thai Nguyen and Can Tho provinces. All self-testing was assisted and observed by peer educators. Both in-person and social network methods were used to mobilize key populations to test for HIV and offer HTS to partners of people living with HIV. Client-level data, including demographic information and self-reported risk behaviour, were collected on site by peer educators. RESULTS: Between January 2017 and May 2018, 3978 persons from key populations were tested through community-led HTS; 66.7% were first-time testers. Of the 3978 clients, 3086 received HTS from a lay provider and 892 self-tested in the presence of a lay provider. Overall, 245 (6.2% of tested clients) had reactive results, 231 (94.3%) were confirmed to be HIV positive; 215/231 (93.1%) initiated antiretroviral therapy (ART). Of 231 adult HIV-positive clients, 186 (80.5%) were provided voluntary aPN, and 105 of their partners were contacted and received HTS. The ratio of partners who tested for HIV per index client was 0.56. Forty-four (41.9%) partners of index clients receiving HTS were diagnosed with HIV, 97.7% initiated ART during the study period. No social harm was identified or reported. CONCLUSIONS: Including aPN as part of community-led HTS for key populations and their partners is feasible and effective, particularly for reaching first-time testers and undiagnosed HIV clients. Scale-up of aPN within community-led HTS for key populations is essential for achieving the United Nations 90-90-90 targets in Vietnam