Quantification of cardiac structure and function using transthoracic echocardiography in term women with HIV

Introduction: In South Africa, up to 30% of pregnant women are human immunodeficiency virus (HIV) positive and morbidity and mortality is high in this group. HIV positive men and women may have multiple cardiovascular comorbidities, which include systolic dysfunction that may progress to heart failure secondary to dilated cardiomyopathy. However the concurrent effect of pregnancy and HIV infection on haemodynamics has not been extensively researched. The aims of this study were to quantify haemodynamics using transthoracic echocardiography (TTE) in term pregnant women with HIV on antiretroviral (ARV) treatment and compare the data with term healthy women in the same population. Method: After ethics approval and written consent, 30 consecutive term HIV positive women and 40 healthy term pregnant women were recruited. HIV positive women had a CD4 count greater than 200 and were either on Highly Active Anti-Retroviral Therapy (HAART) or single drug management. Results: Haemodynamic assessment was possible in all patients and women in the two groups were similar in age, and body mass index. Mean CD4 count was 452 ± 187.8 and duration of therapy was 15.9 ± 22.4 months. Compared with healthy pregnant women, women with HIV have systolic changes exhibited by reductions in left ventricle (LV) septal and right ventricle (RV) systolic myocardial velocities as well as increased LV end-diastolic (ED) areas and diastolic changes of increased RV isovolumetric (IV) relaxation and reduced RV e′ diastolic myocardial velocities. These changes occur in the presence of a reduced LV mass. Pericardial effusions occurred more frequently and are of a larger size in women with HIV. These findings suggest subclinical impairment of systolic function in the LV as well as subclinical impairment of both systolic and diastolic function in the RV. Discussion: Transthoracic echocardiography can quantify cardiac function in healthy pregnant women and in pregnant women with HIV and is acceptable to the patients. HIV positive pregnant women at term on anti-retroviral therapy have hearts that have subclinical systolic dysfunction in the presence of decreased LV mass and increased end-diastolic areas. This may represent a failure to compensate for the increased haemodynamic demands of pregnancy and may be as a result of the direct effects of HIV itself or due to anti-retroviral drugs

Carbon dioxide: making the right connection

Carbon dioxide has been used in anaesthesia since the late 1920s, principally to stimulate breathing after a period of hyperventilation in the era before routine use of capnography. The authors’ tertiary academic hospital still has the infrastructure for pipeline delivery of carbon dioxide. A case is reported of accidental administration of carbon dioxide to a patient under anaesthesia, who was found to have end-tidal carbon dioxide (EtCO2) concentrations of greater than 25 kPa immediately after induction. This was confirmed on arterial blood-gas analysis. After successful resuscitation using an alternative oxygen source, it was discovered that the high concentrations were due to misconnection of gas pipelines during the refurbishment of a theatre. This highlights safety issues concerning pipeline provision of carbon dioxide, and that it is of utmost importance to confirm correct gas connections and supply before a new theatre is commissioned.Keywords: anaesthesia equipment, capnography, hypercarbia, medical erro

Immersion freezing of supercooled water drops containing glassy volcanic ash particles

AbstractThe freezing temperatures of hundreds of water drops with radii 20–50μm containing known average concentrations of suspended, mostly micron- to submicron-sized, volcanic ash particles composed of SiO2-rich glass were recorded using optical microscopy. As expected, the ash suppresses supercooling, and in contrast to earlier studies of much larger ash particles, the median freezing temperature clearly scales with the available ash surface area per drop. The heterogeneous nucleation rate coefficient per unit mass of ash (jm) increases exponentially with decreasing temperature (T) (increasing supercooling) with a possible change in the slope of a plot of logjm against T at T=245±1K. Although uncertainties in the ash surface area limit quantitative comparisons, we conclude that volcanic glass is a less effective ice-nucleating agent than feldspar crystals and more similar to other minerals previously studied

Starvation Resistance is Associated with Developmentally Specified Changes in Sleep, Feeding and Metabolic Rate

Food shortage represents a primary challenge to survival, and animals have adapted diverse developmental, physiological and behavioral strategies to survive when food becomes unavailable. Starvation resistance is strongly influenced by ecological and evolutionary history, yet the genetic basis for the evolution of starvation resistance remains poorly understood. The fruit fly Drosophila melanogaster provides a powerful model for leveraging experimental evolution to investigate traits associated with starvation resistance. While control populations only live a few days without food, selection for starvation resistance results in populations that can survive weeks. We have previously shown that selection for starvation resistance results in increased sleep and reduced feeding in adult flies. Here, we investigate the ontogeny of starvation resistance-associated behavioral and metabolic phenotypes in these experimentally selected flies. We found that selection for starvation resistance resulted in delayed development and a reduction in metabolic rate in larvae that persisted into adulthood, suggesting that these traits may allow for the accumulation of energy stores and an increase in body size within these selected populations. In addition, we found that larval sleep was largely unaffected by starvation selection and that feeding increased during the late larval stages, suggesting that experimental evolution for starvation resistance produces developmentally specified changes in behavioral regulation. Together, these findings reveal a critical role for development in the evolution of starvation resistance and indicate that selection can selectively influence behavior during defined developmental time points

Light-Induced Atomic Desorption for loading a Sodium Magneto-Optical Trap

We report studies of photon-stimulated desorption (PSD), also known as light-induced atomic desorption(LIAD), of sodium atoms from a vacuum cell glass surface used for loading a magneto-optical trap (MOT). Fluorescence detection was used to record the trapped atom number and the desorption rate. We observed a steep wavelength dependence of the desorption process above 2.6 eV photon energy, a result significant for estimations of sodium vapor density in the lunar atmosphere. Our data fit well to a simple model for the loading of the MOT dependent only on the sodium desorption rate and residual gas density. Up to 3.7x10^7 Na atoms were confined under ultra-high vacuum conditions, creating promising loading conditions for a vapor cell based atomic Bose-Einstein condensate of sodium.Comment: Sodium LIAD loaded MOT, 7 pages, 5 figures. Revised submitted manuscript with minor corrections, new data presented, Fig.5 change

Does a powerlifting inspired exercise programme better compliment pain education compared to bodyweight exercise for people with chronic low back pain? A multicentre, single-blind, randomised controlled trial

Background Contemporary management of chronic low back pain involves combined exercise and pain education. Currently, there is a gap in the literature for whether any exercise mode better pairs with pain education. The purpose of this study was to compare general callisthenic exercise with a powerlifting style programme, both paired with consistent pain education, for chronic low back pain. We hypothesised powerlifting style training may better compliment the messages of pain education. Methods An 8-week single-blind randomised controlled trial was conducted comparing bodyweight exercise (n  =  32) with powerlifting (n  =  32) paired with the same education, for people with chronic low back pain. Exercise sessions were one-on-one and lasted 60-min, with the last 5–15 min comprising pain education. Pain, disability, fear, catastrophizing, self-efficacy, anxiety, and depression were measured at baseline, 8-weeks, 3-months, and 6-months. Results No significant between-group differences were observed for pain (p≥0.40), or disability (p≥0.45) at any time-point. Within-group differences were significantly improved for pain (p ≤ 0.04) and disability (p ≤ 0.04) at all time-points for both groups, except 6-month disability in the bodyweight group (p  =  0.1). Behavioural measures explained 39–60% of the variance in changes in pain and disability at each time-point, with fear and self-efficacy emerging as significant in these models (p ≤ 0.001) Conclusions Both powerlifting and bodyweight exercise were safe and beneficial when paired with pain education for chronic low back pain, with reductions in pain and disability associated with improved fear and self-efficacy. This study provides opportunity for practitioners to no longer be constrained by systematic approaches to chronic low back pain

Wake up and smell the bloody Eucalyptus!! Using pluralistic pedagogical approaches to decolonise curricula and advance botanical awareness in first-year undergraduate biology

The weaving of Aboriginal and/or Torres Strait Islander knowledges into higher education curricula is a priority of Universities Australia and remains an ethical obligation for all educators to right the wrongs of the past and make noise to fill the ‘Great Australian Silence’ (W.E.H. Stanner’s 1968 Boyer Lectures). To do so in a culturally respectful way necessitates both co-design and decolonisation of oppressive/restrictive western scientific frameworks. Alternative ways of acquiring and holding knowledge do exist! Similarly, as Biology educators, we must address the ‘Botanical silence’ in Science curricula, where animals are generally prioritised at the expense of plants. This is a symptom of Plant Blindness - a term coined to encapsulate the tendency to ignore plants in our everyday lives (Wandersee & Shussler, 1999). As educators, we have a duty to address this organismal bias. In response, we have conceived a new Practical, ‘Bulu – shadow of a tree’, whose content sits in the shadows cast by the behemoth of western science (e.g., Indigenous knowledges, plants, sensorial experiences, Indigenous Cultural and Intellectual Property (ICIP)). We highlight the constraints of western knowledge acquisition by exploring subjective, botanical, sensory experiences (smell, touch, and taste) that create deep, personalized, place-based memories for students, spawning familiarity and belonging. This outdoors Practical class requires deep observation of plant morphology as we expose the hidden beauty of plants - leaf aromas. We use native plant species, focusing on Eucalyptus spp., to instigate a series of self-reflections to explore the role of subjectivity in Science (Botany) and intellectual property of researchers and their discoveries. Can we objectively describe smells as a means of sharing knowledge? If not, should we abandon our senses and limit our own knowledge acquisition to methodologies sanctioned by colonialist frameworks; frameworks historically used to control First Nations knowledge? Who benefits from the Eucalyptus industry? We will detail how we have employed olfactory pedagogies to enhance place-based learning methodologies thereby initiating conversations, creating campus belonging and stimulating critical reflections on a range of ethical, methodological, and legal (ICIP) aspects of native plants, their products, and derived industries. REFERENCE Wandersee, J., & Schussler, E. (1999). Preventing Plant Blindness. The American Biology Teacher, 61, 82-86. https://doi.org/10.2307/4450624

Securing tropical forest carbon: the contribution of protected areas to REDD

Forest loss and degradation in the tropics contribute 6-17% of all greenhouse gas emissions. Protected areas cover 217.2 million ha (19.6%) of the world's humid tropical forests and contain c. 70.3 petagrams of carbon (Pg C) in biomass and soil to 1 m depth. Between 2000 and 2005, we estimate that 1.75 million ha of forest were lost from protected areas in humid tropical forests, causing the emission of 0.25-0.33 Pg C. Protected areas lost about half as much carbon as the same area of unprotected forest. We estimate that the reduction of these carbon emissions from ongoing deforestation in protected sites in humid tropical forests could be valued at USD 6,200-7,400 million depending on the land use after clearance. This is >1.5 times the estimated spending on protected area management in these regions. Improving management of protected areas to retain forest cover better may be an important, although certainly not sufficient, component of an overall strategy for reducing emissions from deforestation and forest degradation (REDD

On Infrared Excesses Associated With Li-Rich K Giants

Infrared (IR) excesses around K-type red giants (RGs) have previously been discovered using IRAS data, and past studies have suggested a link between RGs with overabundant Li and IR excesses, implying the ejection of circumstellar shells or disks. We revisit the question of IR excesses around RGs using higher spatial resolution IR data, primarily from WISE. Our goal was to elucidate the link between three unusual RG properties: fast rotation, enriched Li, and IR excess. We have 316 targets thought to be K giants, about 40% of which we take to be Li-rich. In 24 cases with previous detections of IR excess at low spatial resolution, we believe that source confusion is playing a role, in that either (a) the source that is bright in the optical is not responsible for the IR flux, or (b) there is more than one source responsible for the IR flux as measured in IRAS. We looked for IR excesses in the remaining sources, identifying 28 that have significant IR excesses by ~20 um (with possible excesses for 2 additional sources). There appears to be an intriguing correlation in that the largest IR excesses are all in Li-rich K giants, though very few Li-rich K giants have IR excesses (large or small). These largest IR excesses also tend to be found in the fastest rotators. There is no correlation of IR excess with the carbon isotopic ratio, 12C/13C. IR excesses by 20 um, though relatively rare, are at least twice as common among our sample of Li-rich K giants. If dust shell production is a common by-product of Li enrichment mechanisms, these observations suggest that the IR excess stage is very short-lived, which is supported by theoretical calculations. Conversely, the Li-enrichment mechanism may only occasionally produce dust, and an additional parameter (e.g., rotation) may control whether or not a shell is ejected.Comment: 73 pages, 21 figures (some of which substantially degraded to meet arXiv file size requirements), accepted to AJ. Full table 1 (and full-res figures) available upon request to the autho