41 research outputs found

    Engineering Valence Band Dispersion for High Mobility p-Type Semiconductors

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    The paucity of high performance transparent p-type semiconductors has been a stumbling block for the electronics industry for decades, effectively hindering the route to efficient transparent devices based on p–n junctions. Cu-based oxides and subsequently Cu-based oxychalcogenides have been heavily studied as affordable, earth-abundant p-type transparent semiconductors, where the mixing of the Cu 3d states with the chalcogenide 2p states at the top of the valence band encourages increased valence band dispersion. In this article, we extend this mixing concept further, by utilizing quantum chemistry techniques to investigate ternary copper phosphides as potential high mobility p-type materials. We use hybrid density functional theory to examine a family of phosphides, namely, MCuP (M = Mg, Ca, Sr, Ba) which all possess extremely disperse valence band maxima, comparable to the dispersion of excellent industry standard n-type transparent conducting oxides. As a proof of concept, we synthesized and characterized powders of CaCuP, showing that they display high levels of p-type conductivity, without any external acceptor dopant. Lastly, we discuss the role of Cu-coordination in promoting valence band dispersion and provide design principles for producing degenerate p-type materials

    Introduction of syphilis point-of-care tests, from pilot study to national programme implementation in Zambia: A qualitative study of healthcare workers' perspectives on testing, training and quality assurance

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    Syphilis affects 1.4 million pregnant women globally each year. Maternal syphilis causes congenital syphilis in over half of affected pregnancies, leading to early foetal loss, pregnancy complications, stillbirth and neonatal death. Syphilis is under-diagnosed in pregnant women. Point-of-care rapid syphilis tests (RST) allow for same-day treatment and address logistical barriers to testing encountered with standard Rapid Plasma Reagin testing. Recent literature emphasises successful introduction of new health technologies requires healthcare worker (HCW) acceptance, effective training, quality monitoring and robust health systems. Following a successful pilot, the Zambian Ministry of Health (MoH) adopted RST into policy, integrating them into prevention of mother-to-child transmission of HIV clinics in four underserved Zambian districts. We compare HCW experiences, including challenges encountered in scaling up from a highly supported NGO-led pilot to a large-scale MoH-led national programme. Questionnaires were administered through structured interviews of 16 HCWs in two pilot districts and 24 HCWs in two different rollout districts. Supplementary data were gathered via stakeholder interviews, clinic registers and supervisory visits. Using a conceptual framework adapted from health technology literature, we explored RST acceptance and usability. Quantitative data were analysed using descriptive statistics. Key themes in qualitative data were explored using template analysis. Overall, HCWs accepted RST as learnable, suitable, effective tools to improve antenatal services, which were usable in diverse clinical settings. Changes in training, supervision and quality monitoring models between pilot and rollout may have influenced rollout HCW acceptance and compromised testing quality. While quality monitoring was integrated into national policy and training, implementation was limited during rollout despite financial support and mentorship. We illustrate that new health technology pilot research can rapidly translate into policy change and scale-up. However, training, supervision and quality assurance models should be reviewed and strengthened as rollout of the Zambian RST programme continues. © 2015, Public Library of Science. All rights reserved. This is an open access article, free of all copyright, and may be freely reproduced, distributed, transmitted, modified, built upon, or otherwise used by anyone for any lawful purpose. The work is made available under the Creative Commons CC0 public domain dedication

    Models of care for patients with hypertension and diabetes in humanitarian crises: a systematic review.

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    Care for non-communicable diseases, including hypertension and diabetes (HTN/DM), is recognized as a growing challenge in humanitarian crises, particularly in low- and middle-income countries (LMICs) where most crises occur. There is little evidence to support humanitarian actors and governments in designing efficient, effective, and context-adapted models of care for HTN/DM in such settings. This article aimed to systematically review the evidence on models of care targeting people with HTN/DM affected by humanitarian crises in LMICs. A search of the MEDLINE, Embase, Global Health, Global Indexus Medicus, Web of Science, and EconLit bibliographic databases and grey literature sources was performed. Studies were selected that described models of care for HTN/DM in humanitarian crises in LMICs. We descriptively analysed and compared models of care using a conceptual framework and evaluated study quality using the Mixed Methods Appraisal Tool. We report our findings according to PRISMA guidelines. The search yielded 10 645 citations, of which 45 were eligible for this review. Quantitative methods were most commonly used (n = 34), with four qualitative, three mixed methods, and four descriptive reviews of specific care models were also included. Most studies detailed primary care facility-based services for HTN/DM, focusing on health system inputs. More limited references were made to community-based services. Health care workforce and treatment protocols were commonly described framework components, whereas few studies described patient centredness, quality of care, financing and governance, broader health policy, and sociocultural contexts. There were few programme evaluations or effectiveness studies, and only one study reported costs. Most studies were of low quality. We concluded that an increasing body of literature describing models of care for patients with HTN/DM in humanitarian crises demonstrated the development of context-adapted services but showed little evidence of impact. Our conceptual framework could be used for further research and development of NCD models of care

    Identification of novel bacteriophages with therapeutic potential targeting Enterococcus faecalis

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    The Gram-positive opportunistic pathogen Enterococcus faecalis is frequently responsible for nosocomial infections in humans and represents one of the most common bacteria isolated from recalcitrant endodontic (root canal) infections. E. faecalis is intrinsically resistant to several antibiotics routinely used in clinical settings (such as cephalosporins and aminoglycosides) and can acquire resistance to vancomycin (vancomycin resistant enterococci, VRE). The resistance of E. faecalis to several classes of antibiotics and its capacity to form biofilms cause serious therapeutic problems. In this paper, we report the isolation of several bacteriophages that target E. faecalis strains isolated from the oral cavity of patients suffering root-canal infections. All phages isolated were Siphoviridae with similar tail lengths (200-250 nm) and icosahedral heads. The genome sequences of three isolated phages were highly conserved with the exception of predicted tail protein genes that diverge in sequence, potentially reflecting host range. The properties of the phage with the broadest host-range (SHEF2), was further characterised. We showed that this phage requires interaction with components of the major and variant region Enterococcal polysaccharide antigen (Epa) to engage in lytic infection. Finally, we explored the therapeutic potential of this phage and showed that it can eradicate E. faecalis biofilms formed in vitro on a standard polystyrene surface but also on a cross-sectional tooth-slice model of endodontic infection. We also show that SHEF2 cleared a lethal infection of zebrafish when applied in the circulation. We therefore propose that the phage described in this study could be used to treat a broad range of antibiotic resistant E. faecalis infections

    Support for UNRWA's survival

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    The United Nations Relief and Works Agency for Palestine Refugees in the Near East (UNRWA) provides life-saving humanitarian aid for 5·4 million Palestine refugees now entering their eighth decade of statelessness and conflict. About a third of Palestine refugees still live in 58 recognised camps. UNRWA operates 702 schools and 144 health centres, some of which are affected by the ongoing humanitarian disasters in Syria and the Gaza Strip. It has dramatically reduced the prevalence of infectious diseases, mortality, and illiteracy. Its social services include rebuilding infrastructure and homes that have been destroyed by conflict and providing cash assistance and micro-finance loans for Palestinians whose rights are curtailed and who are denied the right of return to their homeland

    Characterisation and pure culture of putative health-associated oral bacterium BU063 (Tannerella sp. HOT-286) reveals presence of a potentially novel glycosylated S-layer

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    Tannerella HOT-286 (phylotype BU063) is a recently identified novel filamentous Gram-negative anaerobic oral bacterium cultured for the first time recently in co-culture with Propionibacterium acnes. In contrast to the related periodontal disease associated pathobiont Tannerella forsythia it is considered a putative health-associated bacterium. In this paper we identified that this organism could be grown in pure culture if N-acetyl muramic acid (NAM) was provided in the media, although surprisingly the genetic basis of this phenomenon is not likely to be due to a lack of NAM synthesis genes. During further microbiological investigations we showed for the first time that Tannerella HOT-286 possesses a prominent extracellular S-layer with a novel morphology putatively made up of two proteins modified with an unknown glycan. This data furthers our knowledge of this poorly understood organism and genus that is an important part of the oral and human microbiome

    Strengthening the primary care workforce to deliver high quality care for non-communicable diseases in refugee settings: lessons learnt from a UNHCR partnership

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    Non-communicable disease (NCD) prevention and care in humanitarian contexts has been a long-neglected issue. Health care systems in humanitarian settings have focused heavily on communicable diseases and immediate life-saving health needs. NCDs are a significant cause of morbidity and mortality in refugee settings, however in many situations NCD care is not well integrated into primary health care services. Increased risk of poorer outcomes from Covid 19 for people living with NCDs has heightened the urgency of responding to NCDs and shone a spotlight on their relative neglect in these settings. Partnering with the United Nations Refugee Agency (UNHCR) since 2014, Primary Care International (PCI) has provided clinical guidance and Training of Trainer (ToT) courses on NCDs to 649 health professionals working in primary care in refugee settings in 13 countries. Approximately 2,300 healthcare workers (HCW) have been reached through cascade trainings over the last six years. Our experience has shown that, despite fragile health services, high staff turnover and competing clinical priorities, it is possible to improve NCD knowledge, skills, and practice. ToT programmes are a feasible and practical format to deliver NCD training to mixed groups of healthcare workers (doctors, nurses, technical officers, pharmacy technicians and community health workers). Clinical guidance must be adapted to local settings whilst co-creating an enabling environment for health workers is essential to deliver accessible, high-quality continuity of care for NCDs. On-going support for non clinical systems change is equally critical for sustained impact. A shared responsibility for cascade training - and commitment from local health partners - is necessary to raise NCD awareness, influence local and national policy and to meet the UNHCR’s objective of facilitating access to integrated prevention and control of NCDs

    Magnetic properties of transition metal dimers probed by inelastic neutron scattering

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    The physical characterisation and understanding of molecular magnetic materials is one of the most important steps towards the integration of such systems in hybrid spintronic devices. Amongst the many characterisation techniques employed in such a task, Inelastic Neutron Scattering (INS) stands as one of the most powerful and sensitive tools to investigate their spin dynamics. Herein, the magnetic properties and spin dynamics of two dinuclear complexes, namely [(M(hfacac)2)2(bpym)] (where M = Ni2+, Co2+, abbreviated in the following as Ni2, Co2) are reported. These are model systems that could constitute fundamental units of future spintronic devices. By exploiting the highly sensitive IN5 Cold INS spectrometer, we are able to gain a deep insight into the spin dynamics of Ni2 and to fully obtain the microscopic spin Hamiltonian parameters; while for Co2, a multitude of INS transitions are observed demonstrating the complexity of the magnetic properties of octahedral cobalt-based systems
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