Kinetic simulations of X-B and O-X-B mode conversion

We have performed fully-kinetic simulations of X-B and O-X-B mode conversion in one and two dimensional setups using the PIC code EPOCH. We have recovered the linear dispersion relation for electron Bernstein waves by employing relatively low amplitude incoming waves. The setups presented here can be used to study non-linear regimes of X-B and O-X-B mode conversion.Comment: 4 pages, 3 figure

A 10-year analysis of organ donor referrals to a South African tertiary public sector hospital

Background. South Africa (SA) has one of the lowest deceased organ donor rates in the world (1.4 donors per million population), with thousands of patients awaiting solid-organ transplantation. In order to improve access to transplantation we have to clearly define the reasons for the low deceased donation rate, specific to the population we serve.Objectives. Review of actual donor statistics highlights our successes, yet is not able to contextualise the factors responsible for the unsuccessful conversion of referred organ donors to actual organ donors. In an attempt to identify key factors preventing referred donors from becoming actual donors, we analysed the donor referral patterns at our institution over a 10-year period.Methods. This was a retrospective descriptive study of consecutive deceased donor referrals at Groote Schuur Hospital, Cape Town, SA (from January 2007 to December 2016), utilising a regional donor referral registry. Qualitative and quantitative data were collected and presented as descriptive statistics and temporal trends.Results. Over the 10-year study period, 861 possible organ donors were referred, with a steady increase in the number of referrals over time. Of the referrals, 514 (59.7%) were eligible for donation of at least one solid organ. Of the 508 families that were approached for consent to donation, 342 declined consent for a variety of reasons, resulting in a consent rate of 32.7%. Ultimately, at least one solid organ was obtained from 159 of the 166 consented donors. Despite the increasing number of possible and eligible donors, a statistically significant decline in consent rate was observed over time (ptrend=0.023). Furthermore, increasing trends in medical (as opposed to trauma) (ptrend<0.001) and extended criteria (as opposed to standard criteria) donor referrals (ptrend<0.001) were observed over the 10-year study period.Conclusions. Donor referral patterns have changed over time, with a notable increase in medical and extended criteria donors. Despite the increase in possible and eligible donors, the consent rate has declined. Further qualitative and quantitative research studies are required to understand and address this trend.

Transplant Unit, Division of General Surgery, Department of Surgery, Faculty of Health Sciences, University of Cape Town, South Africa

Organ and tissue donation depends on non-transplant clinicians to identify and timeously refer potential donors and to counsel families compassionately about the prognosis at end of life. Organ donation referral is often felt to be beyond the capacity of district-level hospital services. In this case series, we report on four referrals from a geographically remote, public sector district-level hospital, and review the identification, referral and consent process of potential donors after brain death, and also donors after circulatory death. For the one successfully consented donor we report on the donor work-up and management, and the outcome of the organ recovery and organ allocation process

Access to chloroquine in patients with rheumatic and musculoskeletal diseases attending rheumatology outpatient clinics during the COVID-19 pandemic

Herbal medicines made from the bark of the Cinchona tree, and later quinine, have been widely used for centuries to treat medical conditions such as tropical malaria. More recently, chloroquine (CQ) and its synthetic derivatives have been used as antimalarials and to treat systemic lupus erythematosus, rheumatoid arthritis, and in the past 14 months or so, COVID-19 pneumonia. Anecdotal evidence and the erratic covering through social media of its potential efficacy in the treatment of COVID-19 pneumonia have resulted in the widespread off-label use of CQ in South Africa and worldwide. This study aimed to show that access to CQ as a chronic medication for rheumatic and musculoskeletal diseases was limited during the COVID-19 pandemic, and that this resulted in an increased incidence of flares in these patients, affecting their morbidity and potentially leading to mortality

The diagnostic accuracy of integrated positron emission tomography/computed tomography in the evaluation of pulmonary mass lesions in a tuberculosis-endemic area

Background. Integrated positron emission tomography/computed tomography (PET-CT) is a well-validated modality for assessing pulmonary mass lesions and specifically for estimating risk of malignancy. Tuberculosis (TB) is known to cause false-positive PET-CT findings.Objective. To investigate the utility of PET-CT in the evaluation of pulmonary mass lesions and nodules in a high TB prevalence setting.Methods. All patients referred for the evaluation of a solitary pulmonary nodule or mass and who underwent PET-CT scanning over a 3-year period were included. The PET-CT findings, including maximum standardised uptake value (SUVmax), were compared with the gold standard (tissue or microbiological diagnosis). The sensitivity, specificity, positive and negative predictive values and diagnostic accuracy for malignant disease were calculated according to the SUVmax cut-off of 2.5 and a proposed cut-off obtained from a receiver operating characteristic (ROC) curve.Results. Forty-nine patients (mean (standard deviation) age 60.1 (10.2) years; 29 males) were included, of whom 30 had malignancy. Using an SUVmax cut-off of 2.5, PET-CT had a sensitivity, specificity, positive and negative predictive value and diagnostic accuracy for malignancy of 93.3%, 36.8%, 70.0%, 77.8% and 71.4%, respectively. After a ROC curve analysis, a suggested SUVmax cut-off of 5.0 improved the specificity to 78.9% and the diagnostic accuracy to 86.7%, with a small reduction in sensitivity to 90.0%.Conclusions. The diagnostic accuracy of PET-CT in the evaluation of pulmonary mass lesions using the conventional SUVmax cut-off of 2.5 was reduced in a TB-endemic area. An SUVmax cut-off of 5.0 has a higher specificity and diagnostic accuracy for malignancy, with a comparable sensitivity

A meta-analysis of the efficacy of preoperative surgical safety checklists to improve perioperative outcomes

Background. Meta-analyses of the implementation of a surgical safety checklist (SSC) in observational studies have shown a significant decrease in mortality and surgical complications.Objective. To determine the efficacy of the SSC using data from randomised controlled trials (RCTs).Methods. This meta-analysis followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines and was registered with PROSPERO (CRD42015017546). A comprehensive search of six databases was conducted using the OvidSP search engine.Results. Four hundred and sixty-four citations revealed three eligible trials conducted in tertiary hospitals and a community hospital, with a total of 6 060 patients. All trials had allocation concealment bias and a lack of blinding of participants and personnel. A single trial that contributed 5 295 of the 6 060 patients to the meta-analysis had no detection, attrition or reporting biases. The SSC was associated with significantly decreased mortality (risk ratio (RR) 0.59, 95% confidence interval (CI) 0.42 - 0.85; p=0.0004; I2=0%) and surgical complications (RR 0.64, 95% CI 0.57 - 0.71; p<0.00001; I2=0%). The efficacy of the SSC on specific surgical complications was as follows: respiratory complications RR 0.59, 95% CI 0.21 - 1.70; p=0.33, cardiac complications RR 0.74, 95% CI 0.28 - 1.95; p=0.54, infectious complications RR 0.61, 95% CI 0.29 - 1.27; p=0.18, and perioperative bleeding RR 0.36, 95% CI 0.23 - 0.56; p<0.00001.Conclusions. There is sufficient RCT evidence to suggest that SSCs decrease hospital mortality and surgical outcomes in tertiary and community hospitals. However, randomised evidence of the efficacy of the SSC at rural hospital level is absent

Chronic and structural poverty in South Africa: Challenges for action and research

Ten years after liberation, the persistence of poverty is one of the most important and urgent problems facing South Africa. This paper reflects on some of the findings based on research undertaken as part of the participation of the Programme for Land and Agrarian Studies (PLAAS) at the University of the Western Cape in the work of the Chronic Poverty Research Centre (CPRC), situates it within the broader literature on poverty in South Africa, and considers some emergent challenges. Although PLAAS’s survey, being only the first wave of a panel study, does not yet cast light on short term poverty dynamics, it illuminates key aspects of the structural conditions that underpin long-term poverty: the close interactions between asset poverty, employment-vulnerability and subjection to unequal social power relations. Coming to grips with these dynamics requires going beyond the limitations of conventional ‘sustainable livelihoods’ analyses; and functionalist analyses of South African labour markets. The paper argues for a re-engagement with the traditions of critical sociology, anthropology and the theoretical conventions that allow a closer exploration of the political economy of chronic poverty at micro and macro level

Mycobiome Profiles in Breast Milk from Healthy Women Depend on Mode of Delivery, Geographic Location, and Interaction with Bacteria

Recent studies report the presence of fungal species in breast milk of healthy mothers, suggesting a potential role in infant mycobiome development. In the present work, we aimed to determine whether the healthy human breast milk mycobiota is influenced by geographical location and mode of delivery, as well as to investigate its interaction with bacterial profiles in the same samples. A total of 80 mature breast milk samples from 4 different countries were analyzed by Illumina sequencing of the internal transcribed spacer 1 (ITS1) region, joining the 18S and 5.8S regions of the fungal rRNA region. Basidiomycota and Ascomycota were found to be the dominant phyla, with Malassezia and Davidiella being the most prevalent genera across countries. A core formed by Malassezia, Davidiella, Sistotrema, and Penicillium was shared in the milk samples from the different origins, although specific shifts in mycobiome composition were associated with geographic location and delivery mode. The presence of fungi in the breast milk samples was further confirmed by culture and isolate characterization, and fungal loads were estimated by quantitative PCR (qPCR) targeting the fungal ITS1 region. Cooccurrence network analysis of bacteria and fungi showed complex interactions that were influenced by geographical location, mode of delivery, maternal age, and pregestational body mass index. The presence of a breast milk mycobiome was confirmed in all samples analyzed, regardless of the geographic origin.IMPORTANCE During recent years, human breast milk has been documented as a potential source of bacteria for the newborn. Recently, we have reported the presence of fungi in breast milk from healthy mothers. It is well known that environmental and perinatal factors can affect milk bacteria; however, the impact on milk fungi is still unknown. The current report describes fungal communities (mycobiota) in breast milk samples across different geographic locations and the influence of the mode of delivery. We also provide novel insights on bacterium-fungus interactions, taking into account environmental and perinatal factors. We identified a core of four genera shared across locations, consisting of Malassezia, Davidiella, Sistotrema, and Penicillium, which have been reported to be present in the infant gut. Our data confirm the presence of fungi in breast milk across continents and support the potential role of breast milk in the initial seeding of fungal species in the infant gut

Point-of-Care Ultrasound for Tuberculosis Management in Sub-Saharan Africa-A Balanced SWOT Analysis.

Point-of-care ultrasound (POCUS) is an increasingly accessible skill, allowing for the decentralization of its use to non-specialist healthcare workers to guide routine clinical decision making. The advent of ultrasound-on-a-chip has transformed the technology into a portable mobile health device. Due to its high sensitivity to detect small consolidations, pleural effusions and sub pleural nodules, POCUS has recently been proposed as a sputum-free likely triage tool for tuberculosis (TB). To make an objective assessment of the potential and limitations of POCUS in routine TB management, we present a Strengths, Weaknesses, Opportunities & Threats (SWOT) analysis based on a review of the relevant literature and focusing on Sub-Saharan Africa (SSA). We idenitified numerous strengths and opportunities of POCUS for TB management e.g.; accessible, affordable, easy to use & maintain, expedited diagnosis, extra-pulmonary TB detection, safer pleural/pericardial puncture, use in children/pregnant women/PLHIV, targeted screening of TB contacts, monitoring TB sequelae, and creating AI decision support. Weaknesses and external threats such as operator dependency, lack of visualization of central lung pathology, poor specificity, lack of impact assessments and data from Sub-Saharan Africa must be taken into consideration to ensure that the potential of the technology can be fully realized in research as in practice