224 research outputs found
Hard choices: Ethical challenges in phase 1 of COVID-19 vaccine roll-out in South Africa
Access to COVID-19 vaccines has raised concerns globally. Despite calls for solidarity and social justice during the pandemic, vaccine nationalism, stockpiling of limited vaccine supplies by high-income countries and profit-driven strategies of global pharmaceutical manufacturers have brought into sharp focus global health inequities and the plight of low- and middle-income countries (LMICs) as they wait in line for restricted tranches of vaccines. Even in high-income countries that received vaccine supplies first, vaccine roll-out globally has been fraught with logistic and ethical challenges. South Africa (SA) is no exception. Flawed global institutional strategies for vaccine distribution and delivery have undermined public procurement platforms, leaving LMICs facing disproportionate shortages necessitating strict criteria for vaccine prioritisation. In anticipation of our first consignment of vaccines, deliberations around phase 1 roll-out were intense and contentious. Although the first phase focuses on healthcare personnel (HCP), the devil is in the detail. Navigating the granularity of prioritising different categories of risk in healthcare sectors in SA is complicated by definitions of risk in personal and occupational contexts. The inequitable public-private divide that characterises the SA health system adds another layer of complexity. Unlike other therapeutic or preventive interventions that are procured independently by the private health sector, COVID-19 vaccine procurement is currently limited to the SA government only, leaving HCP in the private sector dependent on central government allocation. Fair distribution among tertiary, secondary and primary levels of care is another consideration. Taking all these complexities into account, procedural and substantive ethical principles supporting a prioritisation approach are outlined. Within the constraints of suboptimal global health governance, LMICs must optimise progressive distribution of scarce vaccines to HCP at highest risk
Erratic dislocations within funnel defects in AlN templates for AlGaN epitaxial layer growth
Advances in childhood immunisation in South Africa: where to now? Programme managers’ views and evidence from systematic reviews.
Background: The Expanded Programme on Immunisation (EPI) is one of the most powerful and cost-effective
public health programmes to improve child survival. We assessed challenges and enablers for the programme in
South Africa, as we approach the 2015 deadline for the Millennium Development Goals.
Methods: Between September 2009 and September 2010 we requested national and provincial EPI managers in
South Africa to identify key challenges facing EPI, and to propose appropriate solutions. We collated their responses
and searched for systematic reviews on the effectiveness of the proposed solutions; in the Health Systems Evidence, Cochrane Library, and PubMed electronic databases. We screened the search outputs, selected systematic reviews, extracted data, and assessed the quality of included reviews (using AMSTAR) and the quality of the evidence (using GRADE) in duplicate; resolving disagreements by discussion and consensus.
Results: Challenges identified by EPI managers were linked to healthcare workers (insufficient knowledge of vaccines and immunisation), the public (anti-immunisation rumours and reluctance from parents), and health system (insufficient financial and human resources). Strategies proposed by managers to overcome the challenges include training, supervision, and audit and feedback; strengthening advocacy and social mobilisation; and sustainable EPI funding schemes, respectively. The findings from reliable systematic reviews indicate that interactive educational meetings, audit and feedback, and supportive supervision improve healthcare worker performance. Structured and interactive communication tools probably increase parents’ understanding of immunisation; and reminders and recall, use of community health workers, conditional cash transfers, and mass media interventions probably increase immunisation coverage. Finally, a national social health insurance scheme is a potential EPI financing mechanism; however, given the absence of high-quality evidence of effects, its implementation should be pilot-tested and the impacts and costs rigorously monitored.
Conclusion: In line with the Millennium Development Goals, we have to ensure that our children’s right to health,
development and survival is respected, protected and promoted. EPI is central to this vision. We found numerous
promising strategies for improving EPI performance in South Africa. However, their implementation would need to
be tailored to local circumstances and accompanied by high-quality monitoring and evaluation. The strength of our
approach comes from having a strong framework for interventions before looking for systematic reviews. Without a
framework, we would have been driven by what reviews have been done and what is easily researchable; rather
than the values and preferences of key immunisation stakeholders
The negotiation and co-construction of meaning and understanding within a postgraduate online learning community
There is an increasing development of courses and course components taught through teaching and learning dialogues online yet there is little secure knowledge regarding the educational quality and outcomes of these dialogues. Drawing on contemporary socio-cultural research, this paper adapts a well-established analytical framework (see Mercer, 1995) that has been developed to understand face to face educational dialogues to the new context of asynchronous electronic conferencing. The work reported is derived from an in-depth case study of a tutorial group of 11 students enrolled on a course within the Open University's MA in Open and Distance Learning. The course was taught on-line to an international cohort of students from wide-ranging academic backgrounds. The analyses of electronic conference archives presented here focus on understanding the students’ on-line collaborative work and the ways in which they constructed meaning, negotiated shared understanding and supported each other in the process of learning at a distance. The implications of the findings for educational practice are considered
Modulation of the silica sol-gel composition for the promotion of direct electron transfer to encapsulated cytochrome
The direct electron transfer between indium-tin oxide electrodes (ITO) and cytochrome c encapsulated in different sol-gel silica networks was studied. Cyt c@silica modified electrodes were synthesized by a two-step encapsulation method mixing a phosphate buffer solution with dissolved cytochrome c and a silica sol prepared by the alcohol-free sol-gel route. These modified electrodes were characterized by cyclic voltammetry, UV-vis spectroscopy, and in situ UV-vis spectroelectrochemistry. The electrochemical response of encapsulated protein is influenced by the terminal groups of the silica pores. Cyt c does not present electrochemical response in conventional silica (hydroxyl terminated) or phenyl terminated silica. Direct electron transfer to encapsulated cytochrome c and ITO electrodes only takes place when the protein is encapsulated in methyl modified silica networks.We gratefully acknowledge Jesus Yanez and Prof. Jose Miguel Martin-Martinez from the Laboratory of Adhesion and Adhesives (University of Alicante) for their assistance in the measurements of contact angle. We also acknowledge the Financial support from the Spanish Ministerio de Economia y Competitividad and FEDER y Ciencia (MAT2010-15273), Generalitat Valenciana (PROMETEO2013/038), and the Fundacion Ramon Areces (CIVP16A1821). Alonso Gamero-Quijano is grateful to Generalitat Valenciana (Santiago Grisolia Program) for the funding of his research fellowship.Gamero-Quijano, A.; Huerta, F.; Morallón, E.; Montilla, F. (2014). Modulation of the silica sol-gel composition for the promotion of direct electron transfer to encapsulated cytochrome. Langmuir. 30(34):10531-10538. https://doi.org/10.1021/la5023517S1053110538303
Optimización del tratamiento farmacológico en pacientes con disfunción sistólica severa del ventrículo izquierdo en una unidad de insuficiencia cardiaca: implicaciones en la indicación de un desfibrilador automático implantable en prevención primaria y factores predictores de ausencia de remodelado reverso del ventrículo izquierdo
Distance education is going through a paradigm shift from the second to the third generation. In the first generation (correspondence education) teachers were craftsmen who coupled traditional learning materials to self-made personalised lessons that they mailed to their students at a distance. In the second generation new,
pedagogically enhanced materials were designed and developed via an industrial model specifically for distance education, but the accent remained on a traditional learning paradigm. In the third generation
personal, competence based, interactive materials for learning communities are being designed and developed.
This chapter first outlines the haracteristics of the first two generations. It then presents a framework for the design, development and delivery of distance education study materials according to the industrial approach. It concludes with a look at how this will change as we go to the third generation. In another chapter
(Valcke, Kirschner & Bos) an environment for this new paradigm is worked out
COMPASS identifies T-cell subsets correlated with clinical outcomes.
Advances in flow cytometry and other single-cell technologies have enabled high-dimensional, high-throughput measurements of individual cells as well as the interrogation of cell population heterogeneity. However, in many instances, computational tools to analyze the wealth of data generated by these technologies are lacking. Here, we present a computational framework for unbiased combinatorial polyfunctionality analysis of antigen-specific T-cell subsets (COMPASS). COMPASS uses a Bayesian hierarchical framework to model all observed cell subsets and select those most likely to have antigen-specific responses. Cell-subset responses are quantified by posterior probabilities, and human subject-level responses are quantified by two summary statistics that describe the quality of an individual's polyfunctional response and can be correlated directly with clinical outcome. Using three clinical data sets of cytokine production, we demonstrate how COMPASS improves characterization of antigen-specific T cells and reveals cellular 'correlates of protection/immunity' in the RV144 HIV vaccine efficacy trial that are missed by other methods. COMPASS is available as open-source software
A blood RNA signature for tuberculosis disease risk: a prospective cohort study.
BACKGROUND: Identification of blood biomarkers that prospectively predict progression of Mycobacterium tuberculosis infection to tuberculosis disease might lead to interventions that combat the tuberculosis epidemic. We aimed to assess whether global gene expression measured in whole blood of healthy people allowed identification of prospective signatures of risk of active tuberculosis disease. METHODS: In this prospective cohort study, we followed up healthy, South African adolescents aged 12-18 years from the adolescent cohort study (ACS) who were infected with M tuberculosis for 2 years. We collected blood samples from study participants every 6 months and monitored the adolescents for progression to tuberculosis disease. A prospective signature of risk was derived from whole blood RNA sequencing data by comparing participants who developed active tuberculosis disease (progressors) with those who remained healthy (matched controls). After adaptation to multiplex quantitative real-time PCR (qRT-PCR), the signature was used to predict tuberculosis disease in untouched adolescent samples and in samples from independent cohorts of South African and Gambian adult progressors and controls. Participants of the independent cohorts were household contacts of adults with active pulmonary tuberculosis disease. FINDINGS: Between July 6, 2005, and April 23, 2007, we enrolled 6363 participants from the ACS study and 4466 from independent South African and Gambian cohorts. 46 progressors and 107 matched controls were identified in the ACS cohort. A 16 gene signature of risk was identified. The signature predicted tuberculosis progression with a sensitivity of 66·1% (95% CI 63·2-68·9) and a specificity of 80·6% (79·2-82·0) in the 12 months preceding tuberculosis diagnosis. The risk signature was validated in an untouched group of adolescents (p=0·018 for RNA sequencing and p=0·0095 for qRT-PCR) and in the independent South African and Gambian cohorts (p values <0·0001 by qRT-PCR) with a sensitivity of 53·7% (42·6-64·3) and a specificity of 82·8% (76·7-86) in the 12 months preceding tuberculosis. INTERPRETATION: The whole blood tuberculosis risk signature prospectively identified people at risk of developing active tuberculosis, opening the possibility for targeted intervention to prevent the disease. FUNDING: Bill & Melinda Gates Foundation, the National Institutes of Health, Aeras, the European Union, and the South African Medical Research Council
High-Resolution Electron Microscopy of Semiconductor Heterostructures and Nanostructures
This chapter briefly describes the fundamentals of high-resolution electron microscopy techniques. In particular, the Peak Pairs approach for strain mapping with atomic column resolution, and a quantitative procedure to extract atomic column compositional information from Z-contrast high-resolution images are presented. It also reviews the structural, compositional, and strain results obtained by conventional and advanced transmission electron microscopy methods on a number of III–V semiconductor nanostructures and heterostructures
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