The role of shear in dissipative gravitational collapse

In this paper we investigate the physics of a radiating star undergoing dissipative collapse in the form of a radial heat flux. Our treatment clearly demonstrates how the presence of shear affects the collapse process; we are in a position to contrast the physical features of the collapsing sphere in the presence of shear with the shear-free case. By employing a causal heat transport equation of the Maxwell-Cattaneo form we show that the shear leads to an enhancement of the core temperature thus emphasizing that relaxational effects cannot be ignored when the star leaves hydrostatic equilibrium.Comment: 15 pages, To appear in Int. J. Mod. Phys.

Physiotherapists’ perception of a community-based primary healthcare clinical education approach to undergraduate learning

Background. South African health systems are challenged by numerous stressors, such as a lack of resources, staff shortages and overburdened public sector demands. This necessitates appropriately equipped and trained healthcare professionals to meet the demands of this system. Community-based primary healthcare (PHC) clinical education is an approach towards preparing health science students to meet these demands. Clinical education is the cornerstone of undergraduate training. Physiotherapists are among the healthcare professionals who require undergraduate training that drives competence for independent practice.Objective. To explore the perceptions and experiences of physiotherapists as clinical supervisors within a physiotherapy undergraduate programme that adopted a community-based PHC approach to clinical training.Methods. An explorative qualitative approach was used, with semi-structured interviews with 10 purposively selected physiotherapists supervising students on the newly introduced platform. Data were transcribed and analysed using content analysis.Results. Seven themes emerged from the data, which relate to curriculum redress, organisational factors, stakeholder dynamics, barriers and enablers to decentralised clinical training, perceived preparedness for practice and recommendations.Conclusions. As the need for an increasing number of health professionals is realised, more innovative methods for clinical education of undergraduate health science students are required. Community-based PHC training for physiotherapy students is one such approach and was generally perceived as a valuable framework to incorporate competencies required for practice as future independent practitioners. Furthermore, improved communication between students, clinicians and academic staff was seen as a recommendation to influence clinical education

The future cost of cancer in South Africa: An interdisciplinary cost management strategy

The exponential rise in cancer costs in South Africa (SA) was illustrated in a recent Sunday Times article entitled ‘The cost of cancer can be a debt sentence’.[1] Our minister of health talks of a ‘war’ against the high costs of cancer drugs, and epidemiologists project a sharply rising incidence. Eminent international medical journals, such as The Lancet, underline the fact that cancer cost is a growing international problem that confronts even the richest countries. Indeed, the question may be posed: if richer countries in the world are battling to cover the costs of cancer, what is the prognosis for SA

Management of HIV-associated cryptococcal disease in South Africa

In routine-care settings, the 10-week mortality associated with cryptococcal meningitis (CM) is high, even with prompt, appropriate antifungal treatment and correctly timed initiation of antiretroviral therapy (ART). While early diagnosis of HIV infection and initiation of ART prior to the development of AIDS is the most important way to reduce the incidence of CM, a cryptococcal antigenaemiascreen-and-treat intervention has the potential to reduce mortality by identifying patients prior to onset of CM. Antifungal treatment for HIV-associated CM is divided into three phases over a minimum period of 1 year: (i) a 2-week induction phase, including intravenous amphotericin B deoxycholate as a backbone; (ii) an 8-week consolidation phase with fluconazole 400 mg daily; and (iii) a maintenance phase with fluconazole 200 mg daily. Amphotericin B should be paired with another antifungal agent to maximise cerebrospinal fluid fungal clearance. World Health Organization guidelines emphasise that patients receiving amphotericin B-containing regimens should have access to a ‘minimum package of toxicity prevention, monitoring and management to minimise the serious amphotericin B-related toxicities particularly hypokalaemia and nephrotoxicity’. Raised intracranial pressure is a serious and often fatal complication of CM, which requires good pressure management with repeat lumbar punctures. ART should be initiated 4 - 6 weeks after starting antifungal therapy. In many cases, relapse CM among South African patients occurs because of suboptimal adherence to secondary prophylaxis with fluconazoleand/or the antifungal not being prescribed

Stereoselective synthesis towards unnatural proline-based amino acids

A catalytic diastereoselective Mannich reaction promoted by chiral bifunctional urea-type organocatalysts has been developed. Treatment of N-Boc-3-ketoproline with N-Boc-aldimines under mild conditions afforded the corresponding unnatural proline based amino acid derivatives with excellent diastereoselectivities (up to 99:1) and enantioselectivities (up to 97% ee). The relative configuration of the chiral reaction products was deduced by the comparsion of the experimentally observed ECD spectra to that obtained theorectically

Analysis of Dominant HIV Quasispecies Suggests Independent Viral Evolution Within Spinal Granulomas Coinfected with Mycobacterium tuberculosis and HIV-1 Subtype C

Extrapulmonary tuberculosis (TB) is a significant public health challenge in South Africa and worldwide, largely fuelled by the HIV epidemic. In spinal TB, Mycobacteria infect the spinal column without dissemination to the spinal cord. The immune microenvironment, target cell characteristics, and other evolutionary forces within granulomas during HIV/TB coinfection are poorly characterized. We investigated whether spinal TB granulomas represent a sequestered anatomical site where independent HIV evolution occurs, and assessed the role of macrophages as a target cell for both HIV and mycobacteria. RNA was extracted from plasma and granulomatous tissue from six antiretroviral-naive HIV-1/spinal TB-coinfected patients, RT-PCR amplified, and the C2-V5 env segment was cloned and sequenced. Analysis of genetic diversity, phylogeny and coalescence patterns was performed on clonal sequences. To investigate their role in HIV sequestration, macrophages and the HIV-1 p24 protein were immune localized and ultrastructural features were studied. Intercompartment diversity measurements and phylogenetic reconstruction revealed anatomically distinct monophyletic HIV-1 clusters in four of six patients. Genotypic CCR5-tropic variants were predominant (98.9%) with conservation of putative N-linked glycosylation sites in both compartments. CD68(+) reactivity was associated with higher tissue viral load (r = 1.0; p < 0.01) but not greater intrapatient diversity (r = 0.60; p > 0.05). Ultrastructural imaging revealed the presence of bacterial and virus-like particles within membrane-bound intracellular compartments of macrophages. Spinal tuberculosis granulomas may form anatomically discreet sites of divergent viral evolution. Macrophages in these granulomas harbored both pathogens, suggesting that they may facilitate the process of viral sequestration within this compartment

Acceptable care? Illness constructions, healthworlds, and accessible chronic treatment in South Africa

Achieving equitable access to health care is an important policy goal, with access influenced by affordability, availability, and acceptability of specific services. We explore patient narratives from a 5-year program of research on health care access to examine relationships between social constructions of illness and the acceptability of health services in the context of tuberculosis treatment and antiretroviral therapy in South Africa. Acceptability of services seems particularly important to the meanings patients attach to illness and care, whereas—conversely—these constructions appear to influence what constitutes acceptability and hence affect access to care. We highlight the underestimated role of individually, socially, and politically constructed healthworlds; traditional and biomedical beliefs; and social support networks. Suggested policy implications for improving acceptability and hence overall health care access include abandoning patronizing approaches to care and refocusing from treating “disease” to responding to “illness” by acknowledging and incorporating patients’ healthworlds in patient–provider interactions

Safe use of Sunitinib in metastatic non-clear cell renal cell cancer in the setting of human immunodeficiency virus

The introduction of targeted therapies has offered the promise of better survival outcomes for patients with metastatic renal cell carcinoma. Sunitinib malate, an oral, multitargeted tyrosine kinase inhibitor, is an important treatment option for patients with metastatic renal cell carcinoma. This case study explores the controversial use of sunitinib in a patient with a non-clear cell variant of renal cell carcinoma, also on treatment with combined antiretroviral treatment for a co-existing human immunodeficiency virus infection