32 research outputs found

    Hydrogen and Muonium behaviour in diamond

    Get PDF
    This work is aimed at the understanding of the dynamical behavior of hydrogen in diamond. The investigation was carried out using Transverse Field muon Spin Rotation (TF-SR) and the Longitudinal Field muon Spin Relaxation (LF-SR) techniques. The chemical analogy between hydrogen (p+e-) and muonium (u+e-) enabled the study of the indirect dynamical behavior of hydrogen in diamond. The TF-SR and LF-SR measurements were carried out in an isotopically pure 13C diamond in the temperature ranges 11 mK - 320 K and 10 K - 400 K, respectively. In the TF-SR results, the Prompt Absolute Fraction (PAF) of both diamagnetic and the paramagnetic states are temperature independent. The spin relaxation rate for the state is non-zero and temperature independent, while that of the Mux state is non-zero and temperature dependent. The behavior of indicates that the u+d is immobile, while that of MuT indicates the mobility in diamond. The LF-SR results provide hop rate and associated nuclear hyperfine interaction parameters of the Mut state in diamond.PhysicsM.Sc. (Physics

    Comparison of Two Methods for Noninvasive Determination of Stroke Volume During Orthostatic Challenge

    Get PDF
    Background: The real time, beat-by-beat, non-invasive determination of stroke volume (SV) is an important parameter in many aerospace related physiologic protocols. In this study, we compared simultaneous estimates of SV calculated from peripheral pulse waveforms with a more conventional non-invasive technique. Methods: Using a prospective, randomized blinded protocol, ten males and nine females completed 12-mm tilt table protocols. The relative change (%(Delta)) in beat-to-beat SV was estimated non-invasively from changes in pulse waveforms measured by application of infrared finger photoplethysmography (IFP) with a Portapres(Registered TradeMark) blood pressure monitoring device and by thoracic impedance cardiography (TIC). The %(Delta) SV values were calculated from continuous SV measurements in the supine posture and over the first 10 s (T1), second 10 s (T2), and 3.5 minutes (T3) of 80deg head-up tilt (HUT). Results: The average %(Delta) SV measured by IFP at T1 (-11.7 +/- 3.7 %) was statistically less (P or = 0.322) than the average %(Delta) SV measured by TIC at T2 (-21.8 +/- 2.5 %), and T3 (-22.6 +/- 2.9 %). Correlation coefficients (r(sup 2)) between IFP and TIC were 0.117 (T1), 0.387 (T2), and 0.7 18 (T3). Conclusion: IFP provides beat-to-beat (real time) assessment of %(Delta) SV after 20 sec of transition to an orthostatic challenge that is comparable to the commonly accepted TIC. Our data support the notion that IFP technology which has flown during space missions can be used to accurately assess physiological status and countermeasure effectiveness for orth static problems that may arise in astronauts after space flight. While the peripherally measured IFP response is slightly delayed, the ease of implementing this monitor in the field is advantageous

    Community-based antiretroviral therapy versus standard clinic-based services for HIV in South Africa and Uganda (DO ART): a randomised trial

    Get PDF
    Background: Community-based delivery of antiretroviral therapy (ART) for HIV, including ART initiation, clinical and laboratory monitoring, and refills, could reduce barriers to treatment and improve viral suppression, reducing the gap in access to care for individuals who have detectable HIV viral load, including men who are less likely than women to be virally suppressed. We aimed to test the effect of community-based ART delivery on viral suppression among people living with HIV not on ART. / Methods: We did a household-randomised, unblinded trial (DO ART) of delivery of ART in the community compared with the clinic in rural and peri-urban settings in KwaZulu-Natal, South Africa and the Sheema District, Uganda. After community-based HIV testing, people living with HIV were randomly assigned (1:1:1) with mobile phone software to community-based ART initiation with quarterly monitoring and ART refills through mobile vans; ART initiation at the clinic followed by mobile van monitoring and refills (hybrid approach); or standard clinic ART initiation and refills. The primary outcome was HIV viral suppression at 12 months. If the difference in viral suppression was not superior between study groups, an a-priori test for non-inferiority was done to test for a relative risk (RR) of more than 0·95. The cost per person virally suppressed was a co-primary outcome of the study. This study is registered with ClinicalTrials.gov, NCT02929992. / Findings: Between May 26, 2016, and March 28, 2019, of 2479 assessed for eligibility, 1315 people living with HIV and not on ART with detectable viral load at baseline were randomly assigned; 666 (51%) were men. Retention at the month 12 visit was 95% (n=1253). At 12 months, community-based ART increased viral suppression compared with the clinic group (306 [74%] vs 269 [63%], RR 1·18, 95% CI 1·07–1·29; psuperiority=0·0005) and the hybrid approach was non-inferior (282 [68%] vs 269 [63%], RR 1·08, 0·98–1·19; pnon-inferiority=0·0049). Community-based ART increased viral suppression among men (73%, RR 1·34, 95% CI 1·16–1·55; psuperiority<0·0001) as did the hybrid approach (66%, RR 1·19, 1·02–1·40; psuperiority=0·026), compared with clinic-based ART (54%). Viral suppression was similar for men (n=156 [73%]) and women (n=150 [75%]) in the community-based ART group. With efficient scale-up, community-based ART could cost US$275–452 per person reaching viral suppression. Community-based ART was considered safe, with few adverse events. / Interpretation: In high and medium HIV prevalence settings in South Africa and Uganda, community-based delivery of ART significantly increased viral suppression compared with clinic-based ART, particularly among men, eliminating disparities in viral suppression by gender. Community-based ART should be implemented and evaluated in different contexts for people with detectable viral load. / Funding: The Bill & Melinda Gates Foundation; the University of Washington and Fred Hutch Center for AIDS Research; the Wellcome Trust; the University of Washington Royalty Research Fund; and the University of Washington King K Holmes Endowed Professorship in STDs and AIDS

    Training a Continent: A Process Evaluation of Virtual Training on Infection Prevention and Control in Africa During COVID-19.

    Get PDF
    BACKGROUND: Strengthening infection prevention and control (IPC) capacity was identified as a key intervention to prepare African Union member states to curb the COVID-19 pandemic. As part of the Africa Taskforce for Coronavirus, which helped implement the Africa Joint Continental Strategy for COVID-19 Outbreak response, the IPC Technical Working Group (IPC TWG) was convened to coordinate the development of IPC core components for preparedness, response, and recovery from COVID-19. As part of the IPC TWG's work, the Africa Centres for Disease Control and Prevention, in collaboration with the Infection Control Africa Network, delivered virtual IPC training sessions targeted to African Union member states. We aimed to undertake a process evaluation of this training to inform and improve both ongoing and future programming. METHODS: The scope of the evaluation was agreed upon through discussion with the training organizers and advisory members and a design workshop. A mixed-methods approach was used; data collection was partly prospective and partly retrospective due to the rapid start of some of the training activities. Existing available data included: usage analytics, the content of questions posed during the webinar and community of practice, and participant feedback survey results. In addition, in-depth qualitative interviews were conducted with a sample of webinar participants. RESULTS: The rapid development of this training was efficient and responsive. The training reached more than 3,000 participants across the 2 rounds, but the numbers varied substantially by location. Participants engaged well during the question period during each webinar, but the asynchronous community of practice was less utilized during the evaluation time frame. Many participants appreciated the African focus of the webinars and gave positive feedback on the practical and context-specific content. CONCLUSIONS: The move toward online training provides an important opportunity to improve IPC across the African continent

    Response to the Novel Corona Virus (COVID-19) Pandemic Across Africa: Successes, Challenges, and Implications for the Future

    Get PDF
    Background: The COVID-19 pandemic has already claimed considerable lives. There are major concerns in Africa due to existing high prevalence rates for both infectious and non-infectious diseases and limited resources in terms of personnel, beds and equipment. Alongside this, concerns that lockdown and other measures will have on prevention and management of other infectious diseases and non-communicable diseases (NCDs). NCDs are an increasing issue with rising morbidity and mortality rates. The World Health Organization (WHO) warns that a lack of nets and treatment could result in up to 18 million additional cases of malaria and up to 30,000 additional deaths in sub-Saharan Africa. Objective: Document current prevalence and mortality rates from COVID-19 alongside economic and other measures to reduce its spread and impact across Africa. In addition, suggested ways forward among all key stakeholder groups. Our Approach: Contextualise the findings from a wide range of publications including internet-based publications coupled with input from senior-level personnel. Ongoing Activities: Prevalence and mortality rates are currently lower in Africa than among several Western countries and the USA. This could be due to a number of factors including early instigation of lockdown and border closures, the younger age of the population, lack of robust reporting systems and as yet unidentified genetic and other factors. Innovation is accelerating to address concerns with available equipment. There are ongoing steps to address the level of misinformation and its consequences including fines. There are also ongoing initiatives across Africa to start addressing the unintended consequences of COVID-19 activities including lockdown measures and their impact on NCDs including the likely rise in mental health disorders, exacerbated by increasing stigma associated with COVID-19. Strategies include extending prescription lengths, telemedicine and encouraging vaccination. However, these need to be accelerated to prevent increased morbidity and mortality. Conclusion: There are multiple activities across Africa to reduce the spread of COVID-19 and address misinformation, which can have catastrophic consequences, assisted by the WHO and others, which appear to be working in a number of countries. Research is ongoing to clarify the unintended consequences given ongoing concerns to guide future activities. Countries are learning from each other

    Examining oral pre-exposure prophylaxis (PrEP) literacy among participants in an HIV vaccine trial preparedness cohort study

    Get PDF
    Background: PrEP literacy is influenced by many factors including the types of information available and how it is interpreted. The level of PrEP literacy may influence acceptability and uptake. Methods: We conducted 25 in-depth interviews in a HIV vaccine trial preparedness cohort study. We explored what participants knew about PrEP, sources of PrEP knowledge and how much they know about PrEP. We used the framework approach to generate themes for analysis guided by the Social Ecological Model and examined levels of PrEP literacy using the individual and interpersonal constructs of the SEM. Results: We found that PrEP awareness is strongly influenced by external factors such as social media and how much participants know about HIV treatment and prevention in the local community. However, while participants highlighted the importance of the internet/social media as a source of information about PrEP they talked of low PrEP literacy in their communities. Participants indicated that their own knowledge came as a result of joining the HIV vaccine trial preparedness study. However, some expressed doubts about the effectiveness of the drug and worried about side effects. Participants commented that at the community level PrEP was associated with being sexually active, because it was used to prevent the sexual transmission of HIV. As a result, some participants commented that one could feel judged by the health workers for asking for PrEP at health facilities in the community. Conclusion: The information collected in this study provided an understanding of the different layers of influence around individuals that are important to address to improve PrEP acceptability and uptake. Our findings can inform strategies to address the barriers to PrEP uptake, particularly at structural and community levels. Trial registration: https://clinicaltrials.gov/ct2/show/NCT04066881

    Language endangerment and language documentation in Africa

    Get PDF
    Non peer reviewe

    Examining oral pre-exposure prophylaxis (PrEP) literacy among participants in an HIV vaccine trial preparedness cohort study

    Get PDF
    Background PrEP literacy is influenced by many factors including the types of information available and how it is interpreted. The level of PrEP literacy may influence acceptability and uptake. Methods We conducted 25 in-depth interviews in a HIV vaccine trial preparedness cohort study. We explored what participants knew about PrEP, sources of PrEP knowledge and how much they know about PrEP. We used the framework approach to generate themes for analysis guided by the Social Ecological Model and examined levels of PrEP literacy using the individual and interpersonal constructs of the SEM. Results We found that PrEP awareness is strongly influenced by external factors such as social media and how much participants know about HIV treatment and prevention in the local community. However, while participants highlighted the importance of the internet/social media as a source of information about PrEP they talked of low PrEP literacy in their communities. Participants indicated that their own knowledge came as a result of joining the HIV vaccine trial preparedness study. However, some expressed doubts about the effectiveness of the drug and worried about side effects. Participants commented that at the community level PrEP was associated with being sexually active, because it was used to prevent the sexual transmission of HIV. As a result, some participants commented that one could feel judged by the health workers for asking for PrEP at health facilities in the community. Conclusion The information collected in this study provided an understanding of the different layers of influence around individuals that are important to address to improve PrEP acceptability and uptake. Our findings can inform strategies to address the barriers to PrEP uptake, particularly at structural and community levels. Trial registration https://clinicaltrials.gov/ct2/show/NCT0406688

    Examining oral pre-exposure prophylaxis (PrEP) literacy among participants in an HIV vaccine trial preparedness cohort study

    Get PDF
    Background: PrEP literacy is influenced by many factors including the types of information available and how it is interpreted. The level of PrEP literacy may influence acceptability and uptake. Methods: We conducted 25 in-depth interviews in a HIV vaccine trial preparedness cohort study. We explored what participants knew about PrEP, sources of PrEP knowledge and how much they know about PrEP. We used the framework approach to generate themes for analysis guided by the Social Ecological Model and examined levels of PrEP literacy using the individual and interpersonal constructs of the SEM. Results: We found that PrEP awareness is strongly influenced by external factors such as social media and how much participants know about HIV treatment and prevention in the local community. However, while participants highlighted the importance of the internet/social media as a source of information about PrEP they talked of low PrEP literacy in their communities. Participants indicated that their own knowledge came as a result of joining the HIV vaccine trial preparedness study. However, some expressed doubts about the effectiveness of the drug and worried about side effects. Participants commented that at the community level PrEP was associated with being sexually active, because it was used to prevent the sexual transmission of HIV. As a result, some participants commented that one could feel judged by the health workers for asking for PrEP at health facilities in the community. Conclusion: The information collected in this study provided an understanding of the different layers of influence around individuals that are important to address to improve PrEP acceptability and uptake. Our findings can inform strategies to address the barriers to PrEP uptake, particularly at structural and community levels. Trial registration: https://clinicaltrials.gov/ct2/show/NCT0406688

    Independent and combined effects of improved water, sanitation, and hygiene, and improved complementary feeding, on child stunting and anaemia in rural Zimbabwe: a cluster-randomised trial.

    Get PDF
    BACKGROUND: Child stunting reduces survival and impairs neurodevelopment. We tested the independent and combined effects of improved water, sanitation, and hygiene (WASH), and improved infant and young child feeding (IYCF) on stunting and anaemia in in Zimbabwe. METHODS: We did a cluster-randomised, community-based, 2 × 2 factorial trial in two rural districts in Zimbabwe. Clusters were defined as the catchment area of between one and four village health workers employed by the Zimbabwe Ministry of Health and Child Care. Women were eligible for inclusion if they permanently lived in clusters and were confirmed pregnant. Clusters were randomly assigned (1:1:1:1) to standard of care (52 clusters), IYCF (20 g of a small-quantity lipid-based nutrient supplement per day from age 6 to 18 months plus complementary feeding counselling; 53 clusters), WASH (construction of a ventilated improved pit latrine, provision of two handwashing stations, liquid soap, chlorine, and play space plus hygiene counselling; 53 clusters), or IYCF plus WASH (53 clusters). A constrained randomisation technique was used to achieve balance across the groups for 14 variables related to geography, demography, water access, and community-level sanitation coverage. Masking of participants and fieldworkers was not possible. The primary outcomes were infant length-for-age Z score and haemoglobin concentrations at 18 months of age among children born to mothers who were HIV negative during pregnancy. These outcomes were analysed in the intention-to-treat population. We estimated the effects of the interventions by comparing the two IYCF groups with the two non-IYCF groups and the two WASH groups with the two non-WASH groups, except for outcomes that had an important statistical interaction between the interventions. This trial is registered with ClinicalTrials.gov, number NCT01824940. FINDINGS: Between Nov 22, 2012, and March 27, 2015, 5280 pregnant women were enrolled from 211 clusters. 3686 children born to HIV-negative mothers were assessed at age 18 months (884 in the standard of care group from 52 clusters, 893 in the IYCF group from 53 clusters, 918 in the WASH group from 53 clusters, and 991 in the IYCF plus WASH group from 51 clusters). In the IYCF intervention groups, the mean length-for-age Z score was 0·16 (95% CI 0·08-0·23) higher and the mean haemoglobin concentration was 2·03 g/L (1·28-2·79) higher than those in the non-IYCF intervention groups. The IYCF intervention reduced the number of stunted children from 620 (35%) of 1792 to 514 (27%) of 1879, and the number of children with anaemia from 245 (13·9%) of 1759 to 193 (10·5%) of 1845. The WASH intervention had no effect on either primary outcome. Neither intervention reduced the prevalence of diarrhoea at 12 or 18 months. No trial-related serious adverse events, and only three trial-related adverse events, were reported. INTERPRETATION: Household-level elementary WASH interventions implemented in rural areas in low-income countries are unlikely to reduce stunting or anaemia and might not reduce diarrhoea. Implementation of these WASH interventions in combination with IYCF interventions is unlikely to reduce stunting or anaemia more than implementation of IYCF alone. FUNDING: Bill & Melinda Gates Foundation, UK Department for International Development, Wellcome Trust, Swiss Development Cooperation, UNICEF, and US National Institutes of Health.The SHINE trial is funded by the Bill & Melinda Gates Foundation (OPP1021542 and OPP113707); UK Department for International Development; Wellcome Trust, UK (093768/Z/10/Z, 108065/Z/15/Z and 203905/Z/16/Z); Swiss Agency for Development and Cooperation; US National Institutes of Health (2R01HD060338-06); and UNICEF (PCA-2017-0002)
    corecore