Solar Disinfection of MODS Mycobacterial Cultures in Resource-Poor Settings

INTRODUCTION: Safe disposal of TB culture material in which the infectious burden of clinical samples has been greatly amplified is an important challenge in resource-limited settings. The bactericidal capacity of solar cookers has been demonstrated previously for conventional bacteria and contaminated clinical waste. We investigated the use of a simple solar cooker for the sterilization of mycobacterial broth cultures from the microscopic observation drug susceptibility assay (MODS). METHODS: Simulated TB culture materials were prepared by inoculating 24-well MODS plates with 500 microL of a known concentration of Mycobacterium bovis BCG. In a series of experiments, samples were simultaneously placed inside a box-type solar cooker and control box and removed at timepoints between 15 minutes and 6 hours. Quantitative cultures were performed using retrieved samples to determine sterilization effect. RESULTS: All cultures from the control box were positive at or within 1-4 logs of inoculation concentration. Simulated culture plates at concentrations from 10(3) colony-forming-units (CFU)/ml to 10(7) CFU/ml were completely sterilized after only one hour of cooker exposure, at temperatures between 50-102 degrees C. At 10(9) CFU/ml (far in excess of diagnostic cultures), it was only possible to recover mycobacterial growth in plates removed after 15 minutes. By 30 minutes all plates were effectively sterilized. DISCUSSION: Solar disinfection provides a very effective, safe and low-cost alternative to conventional equipment used for disposal of mycobacterial culture material. Effect of climatic conditions and optimal operating procedure remain to be defined

Mortality in paediatric burns victims: A retrospective review from 2009 to 2012 in a single centre

Background. Childhood mortality is high in low- and middle-income countries. Burns are one of the five leading causes of childhood injury mortality in South Africa (SA). While there is an abundance of literature on burns in the developed world, there are far fewer publications dealing with childhood mortality related to burns in Africa and SA.Objective. To describe the mortality of children admitted to a dedicated paediatric burns unit, and investigate factors contributing to reducing mortality.Methods. A retrospective review was performed of patients admitted to the Johnson & Johnson Paediatric Burns Unit, Chris Hani Baragwanath Academic Hospital, Johannesburg, SA, between May 2009 and April 2012.Results. During the study period, 1 372 patients aged ≤10 years were admitted to the unit. There were 1 089 admissions to the general ward and 283 admissions to the paediatric burns intensive care unit (PBICU). The overall mortality rate was 7.9% and the rate for children admitted to the PBICU 29.3%; 90.8% of deaths occurred in children aged ≤5 years. Of children admitted with an inhalational injury, 89.5% died. No child with a burn injury >60% of total body surface area (TBSA) survived.Conclusions. Our overall mortality rate was 7.9%, and the rate declined significantly over the 3-year study period from 11.7% to 5.1%. Age ≤5 years, the presence of inhalational injury, burn injury >30% of TBSA and admission to the PBICU were significant risk factors for mortality

A Two-sided Loop X-Ray Solar Coronal Jet Driven by a Minifilament Eruption

Most of the commonly discussed solar coronal jets are the type that consist of a single spire extending approximately vertically from near the solar surface into the corona. Recent research supports that eruption of a miniature filament (minifilament) drives many such single-spire jets and concurrently generates a miniflare at the eruption site. A different type of coronal jet, identified in X-ray images during the Yohkoh era, are two-sided loop jets, which extend from a central excitation location in opposite directions, along low-lying coronal loops that are more-or-less horizontal to the surface. We observe such a two-sided loop jet from the edge of active region (AR) 12473, using data from Hinode X-Ray Telescope (XRT) and Extreme Ultraviolet Imaging Spectrometer (EIS), and from Solar Dynamics Observatory's (SDO) Atmospheric Imaging Assembly (AIA) and Helioseismic and Magnetic Imager (HMI). Similar to single-spire jets, this two-sided loop jet results from eruption of a minifilament, which accelerates to over 140 km s−1 before abruptly stopping after striking an overlying nearly horizontal-loop field at ~30,000 km in altitude and producing the two-sided loop jet. An analysis of EIS raster scans shows that a hot brightening, consistent with a small flare, develops in the aftermath of the eruption, and that Doppler motions (~40 km s−1) occur near the jet formation region. As with many single-spire jets, the magnetic trigger here is apparently flux cancelation, which occurs at a rate of ~4 × 1018 Mx hr−1, broadly similar to the rates observed in some single-spire quiet-Sun and AR jets. An apparent increase in the (line-of-sight) flux occurs within minutes of the onset of the minifilament eruption, consistent with the apparent increase being due to a rapid reconfiguration of low-lying fields during and soon after the minifilament-eruption onset

UBC-Nepal Expedition: Acute alterations in sympathetic nervous activity do not influence brachial artery endothelial function at sea-level and high-altitude.

Evidence indicates that increases in sympathetic nervous activity (SNA), and acclimatization to high-altitude (HA), may reduce endothelial function as assessed by brachial artery flow-mediated dilatation (FMD); however, it is unclear whether such changes in FMD are due to direct vascular constraint, or consequential altered hemodynamics (e.g. shear stress) associated with increased SNA as a consequence of exposure to HA. We hypothesized that: 1) at rest, SNA would be elevated and FMD would be reduced at HA compared to sea-level (SL); and 2) at SL and HA, FMD would be reduced when SNA was acutely increased, and elevated when SNA was acutely decreased. Using a novel, randomized experimental design, brachial artery FMD was assessed at SL (344m) and HA (5050m) in 14 participants during mild lower-body negative pressure (LBNP; -10 mmHg) and lower-body positive pressure (LBPP; +10 mmHg). Blood pressure (finger photoplethysmography), heart rate (electrodcardiogram), oxygen saturation (pulse oximetry), and brachial artery blood flow and shear rate (Duplex ultrasound) were recorded during LBNP, control, and LBPP trials. Muscle SNA was recorded (via microneurography) in a subset of participants (n=5). Our findings were: 1) at rest, SNA was elevated (P<0.01), and absolute FMD was reduced (P=0.024), but relative FMD remained unaltered (P=0.061), at HA compared to SL, and 2) despite significantly altering SNA with LBNP (+60.3±25.5%) and LBPP (-37.2±12.7%) (P<0.01), FMD was unaltered at SL (P=0.448), and HA (P=0.537). These data indicate that acute and mild changes in SNA do not directly influence brachial artery FMD at SL or HA

UBC-Nepal Expedition: Acute alterations in sympathetic nervous activity do not influence brachial artery endothelial function at sea-level and high-altitude.

Evidence indicates that increases in sympathetic nervous activity (SNA), and acclimatization to high-altitude (HA), may reduce endothelial function as assessed by brachial artery flow-mediated dilatation (FMD); however, it is unclear whether such changes in FMD are due to direct vascular constraint, or consequential altered hemodynamics (e.g. shear stress) associated with increased SNA as a consequence of exposure to HA. We hypothesized that: 1) at rest, SNA would be elevated and FMD would be reduced at HA compared to sea-level (SL); and 2) at SL and HA, FMD would be reduced when SNA was acutely increased, and elevated when SNA was acutely decreased. Using a novel, randomized experimental design, brachial artery FMD was assessed at SL (344m) and HA (5050m) in 14 participants during mild lower-body negative pressure (LBNP; -10 mmHg) and lower-body positive pressure (LBPP; +10 mmHg). Blood pressure (finger photoplethysmography), heart rate (electrodcardiogram), oxygen saturation (pulse oximetry), and brachial artery blood flow and shear rate (Duplex ultrasound) were recorded during LBNP, control, and LBPP trials. Muscle SNA was recorded (via microneurography) in a subset of participants (n=5). Our findings were: 1) at rest, SNA was elevated (P<0.01), and absolute FMD was reduced (P=0.024), but relative FMD remained unaltered (P=0.061), at HA compared to SL, and 2) despite significantly altering SNA with LBNP (+60.3±25.5%) and LBPP (-37.2±12.7%) (P<0.01), FMD was unaltered at SL (P=0.448), and HA (P=0.537). These data indicate that acute and mild changes in SNA do not directly influence brachial artery FMD at SL or HA

T-cell subpopulations αβ and γδ in cord blood of very preterm infants : The influence of intrauterine infection

Open Access: This article is distributed under the terms of the Creative Commons Attribution License which permits any use, distribution, and reproduction in any medium, provided the original author(s) and the source are creditedPreterm infants are very susceptible to infections. Immune response mechanisms in this group of patients and factors that influence cord blood mononuclear cell populations remain poorly understood and are considered insufficient. However, competent immune functions of the cord blood mononuclear cells are also described. The aim of this work was to evaluate the T-cell population (CD3+) with its subpopulations bearing T-cell receptor (TCR) αβ or TCR γδ in the cord blood of preterm infants born before 32 weeks of gestation by mothers with or without an intrauterine infection. Being a pilot study, it also aimed at feasibility check and assessment of an expected effect size. The cord blood samples of 46 infants age were subjected to direct immunofluorescent staining with monoclonal antibodies and then analyzed by flow cytometry. The percentage of CD3+ cells in neonates born by mothers with diagnosis of intrauterine infection was significantly lower than in neonates born by mothers without infection (p = 0.005; Mann-Whitney U test). The number of cells did not differ between groups. Infection present in the mother did not have an influence on the TCR αβ or TCR γδ subpopulations. Our study contributes to a better understanding of preterm infants' immune mechanisms, and sets the stage for further investigations.Peer reviewedFinal Published versio

Observation of An Evolving Magnetic Flux Rope Prior To and During A Solar Eruption

Explosive energy release is a common phenomenon occurring in magnetized plasma systems ranging from laboratories, Earth's magnetosphere, the solar corona and astrophysical environments. Its physical explanation is usually attributed to magnetic reconnection in a thin current sheet. Here we report the important role of magnetic flux rope structure, a volumetric current channel, in producing explosive events. The flux rope is observed as a hot channel prior to and during a solar eruption from the Atmospheric Imaging Assembly (AIA) telescope on board the Solar Dynamic Observatory (SDO). It initially appears as a twisted and writhed sigmoidal structure with a temperature as high as 10 MK and then transforms toward a semi-circular shape during a slow rise phase, which is followed by fast acceleration and onset of a flare. The observations suggest that the instability of the magnetic flux rope trigger the eruption, thus making a major addition to the traditional magnetic-reconnection paradigm.Comment: 13 pages, 3 figure