Retrieval of material properties of monolayer transition-metal dichalcogenides from magnetoexciton energy spectra

Reduced exciton mass, polarizability, and dielectric constant of the surrounding medium are essential properties for semiconduction materials, and they can be extracted recently from the magnetoexciton energies. However, the acceptable accuracy of the previously suggested method requires very high magnetic intensity. Therefore, in the present paper, we propose an alternative method of extracting these material properties from recently available experimental magnetoexciton s-state energies in monolayer transition-metal dichalcogenides (TMDCs). The method is based on the high sensitivity of exciton energies to the material parameters in the Rytova-Keldysh model. It allows us to vary the considered material parameters to get the best fit of the theoretical calculation to the experimental exciton energies for the $1s$, $2s$, and $3s$ states. This procedure gives values of the exciton reduced mass and 2D polarizability. Then, the experimental magnetoexciton spectra compared to the theoretical calculation gives also the average dielectric constant. Concrete applications are presented only for monolayers WSe$_2$ and WS$_2$ from the recently available experimental data. However, the presented approach is universal and can be applied to other monolayer TMDCs. The mentioned fitting procedure requires a fast and effective method of solving the Schr\"{o}dinger of an exciton in monolayer TMDCs with a magnetic field. Therefore, we also develop such a method in this study for highly accurate magnetoexciton energies.Comment: 8 pages, 4 figures, 4 table

Benefits and limitations of text messages to stimulate higher learning among community providers: participants’ views of an mHealth intervention to support continuing medical education in Vietnam

BACKGROUND: A randomized controlled trial was conducted in 2015 to evaluate a mobile continuing medical education (mCME) intervention that provided daily text messages to community-based physicians’ assistants (CBPAs) in Thai Nguyen Province, Vietnam. Although the intervention failed to improve medical knowledge over a 6-month period, a companion qualitative study provided insights on the views and experiences of intervention participants. METHODS: We conducted focus group discussions (FGDs) and in-depth interviews (IDIs) among participants randomized to receive text messages containing either simple medical facts or quiz questions. Trained interviewers collected data immediately following the conclusion of the trial in December 2015. Using semi-structured question guides, respondents were queried on their views of the intervention, positive and negative, and perceived impacts of the intervention. During analysis, after learning that the intervention had failed to increase knowledge among participants, we also examined reasons for lack of improvement in medical knowledge. All analyses were performed in NVivo using a thematic approach. RESULTS: A total of 70 CBPAs engaged in one of 8 FGDs or an IDI. One-half were men; average age among all respondents was 40 years. Most (81%) practiced in rural settings and most (51%) focused on general medicine. The mean length of work experience was 3 years. All respondents made positive comments about the intervention; convenience, relevance, and quick feedback (quiz format) were praised. Downsides encompassed lack of depth of information, weak interaction, technology challenges, and challenging/irrelevant messages. Respondents described perceived impacts encompassing increased motivation, knowledge, collegial discussions, Internet use to search for more information, and clinical skills. Overall, they expressed a desire for the intervention to continue and recommended expansion to other medical professionals. Overreliance on the text messages, lack of effective self-study, and technical/language-based barriers may be potential explanations for intervention failure. CONCLUSION: As a form of mCME, daily text messages were well-received by community-level health care providers in Vietnam. This mCME approach appears very promising in low-resource environments or where traditional forms of CME are impractical. Future models might consider enhancements to foster linkages to relevant medical materials, improve interaction with medical experts, and tailor medical content to the daily activities of medical staff

The CCR5 antagonist maraviroc exerts limited neuroprotection without improving neurofunctional outcome in experimental pneumococcal meningitis.

One-third of pneumococcal meningitis (PM) survivors suffer from neurological sequelae including learning disabilities and hearing loss due to excessive neuroinflammation. There is a lack of efficacious compounds for adjuvant therapy to control this long-term consequence of PM. One hallmark is the recruitment of leukocytes to the brain to combat the bacterial spread. However, this process induces excessive inflammation, causing neuronal injury. Maraviroc (MVC)-a CCR5 antagonist-was demonstrated to inhibit leukocyte recruitment and attenuate neuroinflammation in several inflammatory diseases. Here, we show that in vitro, MVC decreased nitric oxide production in astroglial cells upon pneumococcal stimulation. In vivo, infant Wistar rats were infected with 1 × 104 CFU/ml S. pneumoniae and randomized for treatment with ceftriaxone plus MVC (100 mg/kg) or ceftriaxone monotherapy. During the acute phase, neuroinflammation in the CSF was measured and histopathological analyses were performed to determine neuronal injury. Long-term neurofunctional outcome (learning/memory and hearing capacity) after PM was assessed. MVC treatment reduced hippocampal cell apoptosis but did not affect CSF neuroinflammation and the neurofunctional outcome after PM. We conclude that MVC treatment only exerted limited effect on the pathophysiology of PM and is, therefore, not sufficiently beneficial in this experimental paradigm of PM

The CIPAZ study protocol: an open label randomised controlled trial of azithromycin versus ciprofloxacin for the treatment of children hospitalised with dysentery in Ho Chi Minh City, Vietnam

Background: Diarrhoeal disease remains a common cause of illness and death in children <5 years of age. Faecal-oral infection by Shigella spp. causing bacillary dysentery is a leading cause of moderate-to-severe diarrhoea, particularly in low and middle-income countries. In Southeast Asia, S. sonnei predominates and infections are frequently resistant to first-line treatment with the fluoroquinolone, ciprofloxacin. While resistance to all antimicrobials is increasing, there may be theoretical and clinical benefits to prioritizing treatment of bacillary dysentery with the azalide, azithromycin. In this study we aim to measure the efficacy of treatment with azithromycin compared with ciprofloxacin, the current standard of care, for the treatment of children with bacillary dysentery. Methods and analysis: We will perform a multicentre, open-label, randomized controlled trial of two therapeutic options for the antimicrobial treatment of children hospitalised with dysentery. Children (6–60 months of age) presenting with symptoms and signs of dysentery at Children’s Hospital 2 in Ho Chi Minh City will be randomised (1:1) to treatment with either oral ciprofloxacin (15mg/kg/twice daily for 3 days, standard-of-care) or oral azithromycin (10mg/kg/daily for 3 days). The primary endpoint will be the proportion of treatment failure (defined by clinical and microbiological parameters) by day 28 (+3 days) and will be compared between study arms by logistic regression modelling using treatment allocation as the main variable. Ethics and dissemination: The study protocol (version 1.2 dated 27th December 2018) has been approved by the Oxford Tropical Research Ethics Committee (47–18) and the ethical review boards of Children's Hospital 2 (1341/NĐ2-CĐT). The study has also been approved by the Vietnamese Ministry of Health (5044/QĐ-BYT). Trial registration: Clinicaltrials.gov: NCT03854929 (February 26th 2019)

Assessing decentralised policy implementation in Vietnam : The case of land recovery and resettlement in the Vung Ang Economic Zone

From 2006 plans were implemented to create a deep-sea water port linked to an Economic Zone in the coastal Province of Ha Tinh, located in north central Vietnam. The multi-purpose Zone entitled ‘Vung Ang’, was to attract foreign investors, while the port would provide a link to nearby Laos and Thailand. The project obviously had large implications for the administrations at various levels of governance from Hanoi to the coastal communes and villages, but even more serious impacts on the people living in the affected areas. A large area of about 23,000 hectares was to be cleared, affecting the people of 9 communes, in some of which all inhabitants had to leave their houses and homesteads, to be relocated to completely new settlements about 10 miles inland. These tightly knit communities were not too happy with the prospect to leave their homes and land, the burial places of their ancestors, and the long term comforts of community support networks. While initial decision making process started at the highest levels of Vietnam Governance, the implementation of port and industrial park construction and the related relocation policy was delegated to Ha Tinh province, which is consistent with current decentralisation policies in Vietnam. Actual implementation was carried out by the affected District and Commune level officials – with support from the Communist Party led Mass Organisations – who were in charge of the planning and implementation of the relocation process. This entailed a complex and sensitive series of steps to inform affected households, prepare relocation areas and allocate compensation and alternative housing. This paper describes the implementation dynamics of relocation by depicting and assessing the roles of all stakeholders involved, including the impacts - for better or for worse – of the relocated households. It brings out the way local authorities dealt with affected people, including efforts linked to the ideal of grass-roots democracy. Key areas of contestation are uncovered, such as inadequate infrastructure and low compensation rates. The paper has a second objective to assess the degree to which decentralisation in Vietnam has been actually implemented, and how this affects policy making processes such as the Vung Ang port/industrial zone project. The paper concludes that the relocation policy was implemented in a fairly efficient and harmonious way – with a very intensive engagement of the entire provincial administrative machinery, but that it is too early to assess the livelihood opportunities of the relocated households