A clinical audit of the utilisation of red cell products in elective total hip replacement surgery

Background. Previous studies have documented a marked variation in transfusion practice for total hip replacement (THR)  surgery. Objective. To audit red cell product utilisation for THR at two Western Cape tertiary referral hospitals (HY and HG).  Methods. The folders of 207 consecutive patients undergoing elective THR surgery from January 2013 to December 2013 were  reviewed. Information relating to age, sex, clinical observations, indications for surgery, pre- and postoperative  haemoglobin (Hb) values, comorbidities, length of hospital stay and transfusion history was recorded.Results. The transfusion rate at HY (41.6%) was significantly higher than that at HG (10.0%). The mean postoperative Hb in the transfused patients at HG was 8.3 g/dL v. 9.1 g/dL at HY. Females had a significantly higher transfusion rate (33.0%) than males (15.0%) (p<0.05), and the mean age of transfused patients was significantly greater than that of untransfused patients  (p<0.005). Although patients with comorbidities had a higher transfusion rate than those without, this did not reach statistical  significance. Of 120 patients with complete data, 113 (94.2%) had a blood bank order, of which the vast majority, 102/113  (90.3%), were group-and-screen (G&S) requests; 29/113 (25.7%) were converted to a full crossmatch.Conclusions. Overall, the transfusion rate for both hospitals was 25.8%, which is well within published rates. A guideline Hb trigger of 8.0 g/dL is recommended as per published guidelines, with the caveat that the clinical judgement of the attending clinician whether a transfusion is indicated is paramount. Causes of preoperative anaemia should be investigated and treated. Routine cross-matching preoperatively is unnecessary, and a G&S order is sufficient

Chlamydia trachomatis Biovar L2 Infection in Women in South Africa

We detected Chlamydia trachomatis biovar L2 in vaginal swab specimens of 7 women with vaginal discharge in South Africa. Whole-genome sequencing directly from clinical specimens identified a closely related cluster of strains. The clinical role of this infection in the context of syndromic management should be clarified

Myositis associated with localized lipodystrophy: an unrecognized condition?

Lipodystrophies represent a heterogeneous group of diseases characterized by altered body fat repartition and often metabolic alterations. Here we illustrate a 20 year old male with myositis in association with localized lipodystrophy. Immunohistochemical stainings revealed a regular pattern of dystrophin, dysferlin, sarcoglycans, and theletonin. Furtermore, there was no evidence of Lamin A/C deficiency. A nearly identical clinical and histological picture has been described in three patients up to now. Although it is difficult to speculate on a causative pathophysiological mechanism at this time, it is possible that this association represents an unrecognized condition

On special quadratic birational transformations of a projective space into a hypersurface

We study transformations as in the title with emphasis on those having smooth connected base locus, called "special". In particular, we classify all special quadratic birational maps into a quadric hypersurface whose inverse is given by quadratic forms by showing that there are only four examples having general hyperplane sections of Severi varieties as base loci.Comment: Accepted for publication in Rendiconti del Circolo Matematico di Palerm

Autonomous decision-making against induced seismicity in deep fluid injections

The rise in the frequency of anthropogenic earthquakes due to deep fluid injections is posing serious economic, societal, and legal challenges to geo-energy and waste-disposal projects. We propose an actuarial approach to mitigate this risk, first by defining an autonomous decision-making process based on an adaptive traffic light system (ATLS) to stop risky injections, and second by quantifying a "cost of public safety" based on the probability of an injection-well being abandoned. The ATLS underlying statistical model is first confirmed to be representative of injection-induced seismicity, with examples taken from past reservoir stimulation experiments (mostly from Enhanced Geothermal Systems, EGS). Then the decision strategy is formalized: Being integrable, the model yields a closed-form ATLS solution that maps a risk-based safety standard or norm to an earthquake magnitude not to exceed during stimulation. Finally, the EGS levelized cost of electricity (LCOE) is reformulated in terms of null expectation, with the cost of abandoned injection-well implemented. We find that the price increase to mitigate the increased seismic risk in populated areas can counterbalance the heat credit. However this "public safety cost" disappears if buildings are based on earthquake-resistant designs or if a more relaxed risk safety standard or norm is chosen.Comment: 8 pages, 4 figures, conference (International Symposium on Energy Geotechnics, 26-28 September 2018, Lausanne, Switzerland

A weak characterization of slow variables in stochastic dynamical systems

We present a novel characterization of slow variables for continuous Markov processes that provably preserve the slow timescales. These slow variables are known as reaction coordinates in molecular dynamical applications, where they play a key role in system analysis and coarse graining. The defining characteristics of these slow variables is that they parametrize a so-called transition manifold, a low-dimensional manifold in a certain density function space that emerges with progressive equilibration of the system's fast variables. The existence of said manifold was previously predicted for certain classes of metastable and slow-fast systems. However, in the original work, the existence of the manifold hinges on the pointwise convergence of the system's transition density functions towards it. We show in this work that a convergence in average with respect to the system's stationary measure is sufficient to yield reaction coordinates with the same key qualities. This allows one to accurately predict the timescale preservation in systems where the old theory is not applicable or would give overly pessimistic results. Moreover, the new characterization is still constructive, in that it allows for the algorithmic identification of a good slow variable. The improved characterization, the error prediction and the variable construction are demonstrated by a small metastable system

Precision Measurement of the Newtonian Gravitational Constant Using Cold Atoms

About 300 experiments have tried to determine the value of the Newtonian gravitational constant, G, so far, but large discrepancies in the results have made it impossible to know its value precisely. The weakness of the gravitational interaction and the impossibility of shielding the effects of gravity make it very difficult to measure G while keeping systematic effects under control. Most previous experiments performed were based on the torsion pendulum or torsion balance scheme as in the experiment by Cavendish in 1798, and in all cases macroscopic masses were used. Here we report the precise determination of G using laser-cooled atoms and quantum interferometry. We obtain the value G=6.67191(99) x 10^(-11) m^3 kg^(-1) s^(-2) with a relative uncertainty of 150 parts per million (the combined standard uncertainty is given in parentheses). Our value differs by 1.5 combined standard deviations from the current recommended value of the Committee on Data for Science and Technology. A conceptually different experiment such as ours helps to identify the systematic errors that have proved elusive in previous experiments, thus improving the confidence in the value of G. There is no definitive relationship between G and the other fundamental constants, and there is no theoretical prediction for its value, against which to test experimental results. Improving the precision with which we know G has not only a pure metrological interest, but is also important because of the key role that G has in theories of gravitation, cosmology, particle physics and astrophysics and in geophysical models.Comment: 3 figures, 1 tabl

Ambient PM2.5 Exposure Up-regulates the Expression of Costimulatory Receptors on Circulating Monocytes in Diabetic Individuals

BACKGROUND: Exposure of humans to air pollutants such as ozone and particulate matter (PM) may result in airway and systemic inflammation and altered immune function. One putative mechanism may be through modification of cell-surface costimulatory molecules. OBJECTIVES: We examined whether changes in expression of costimulatory molecules on circulating cells are associated with ambient levels of fine PM [aerodynamic diameter ≤ 2.5 μm (PM2.5)] in a susceptible population of diabetic individuals. METHODS: Twenty subjects were studied for 4 consecutive days. Daily measurements of PM2.5 and meteorologic data were acquired on the rooftop of the exam site. Circulating cell-surface markers that mediate innate immune and inflammatory responses were assessed by flow cytometry on each day. Sensitivity analysis was conducted on glutathione S-transferase M1 (GSTM1) genotype, body mass index, and glycosylated hemoglobin A1c (HbA1c) levels to determine their role as effect modifiers. Data were analyzed using random effects models adjusting for season, weekday, and meteorology. RESULTS: We found significantly increased monocyte expression (mean fluorescent intensity) of CD80, CD40, CD86, HLA-DR, and CD23 per 10-μg/m3 increase in PM2.5 at 2- to 4-day lag times after exposure. These findings were significantly higher in obese individuals, in individuals with HbA1c > 7%, and in participants who were GSTM1 null. CONCLUSIONS: Exposure to PM2.5 can enhance antigen-presenting cell phenotypes on circulating cells, which may have consequences in the development of allergic or autoimmune diseases. These effects are amplified in diabetic individuals with characteristics that are associated with insulin resistance or with oxidative stress

Complete analysis of the B-cell response to a protein antigen, from in vivo germinal centre formation to 3-D modelling of affinity maturation

Somatic hypermutation of immunoglobulin variable region genes occurs within germinal centres (GCs) and is the process responsible for affinity maturation of antibodies during an immune response. Previous studies have focused almost exclusively on the immune response to haptens, which may be unrepresentative of epitopes on protein antigens. In this study, we have exploited a model system that uses transgenic B and CD4<sup>+</sup> T cells specific for hen egg lysozyme (HEL) and a chicken ovalbumin peptide, respectively, to investigate a tightly synchronized immune response to protein antigens of widely differing affinities, thus allowing us to track many facets of the development of an antibody response at the antigen-specific B cell level in an integrated system <i>in</i> <i>vivo</i>. Somatic hypermutation of immunoglobulin variable genes was analysed in clones of transgenic B cells proliferating in individual GCs in response to HEL or the cross-reactive low-affinity antigen, duck egg lysozyme (DEL). Molecular modelling of the antibody–antigen interface demonstrates that recurring mutations in the antigen-binding site, selected in GCs, enhance interactions of the antibody with DEL. The effects of these mutations on affinity maturation are demonstrated by a shift of transgenic serum antibodies towards higher affinity for DEL in DEL-cOVA immunized mice. The results show that B cells with high affinity antigen receptors can revise their specificity by somatic hypermutation and antigen selection in response to a low-affinity, cross-reactive antigen. These observations shed further light on the nature of the immune response to pathogens and autoimmunity and demonstrate the utility of this novel model for studies of the mechanisms of somatic hypermutation

Psychosocial, Behavioural and Health System Barriers to Delivery and Uptake of Intermittent Preventive Treatment of Malaria in Pregnancy in Tanzania - Viewpoints of Service Providers in Mkuranga and Mufindi Districts.

Intermittent preventive treatment of malaria in pregnancy (IPTp) using sulphurdoxine-pyrimethamine (SP) is one of key malaria control strategies in Africa. Yet, IPTp coverage rates across Africa are still low due to several demand and supply constraints. Many countries implement the IPTp-SP strategy at antenatal care (ANC) clinics. This paper reports from a study on the knowledge and experience of health workers (HWs) at ANC clinics regarding psychosocial, behavioural and health system barriers to IPTp-SP delivery and uptake in Tanzania. Data were collected through questionnaire-based interviews with 78 HWs at 28 ANC clinics supplemented with informal discussions with current and recent ANC users in Mkuranga and Mufindi districts. Qualitative data were analysed using a qualitative content analysis approach. Quantitative data derived from interviews with HWs were analysed using non-parametric statistical analysis. The majority of interviewed HWs were aware of the IPTp-SP strategy's existence and of the recommended one month spacing of administration of SP doses. Some HWs were unsure of that it is not recommended to administer IPTp-SP and ferrous/folic acid concurrently. Others were administering three doses of SP per client following instruction from a non-governmental agency while believing that this was in conflict with national guidelines. About half of HWs did not find it appropriate for the government to recommend private ANC providers to provide IPTp-SP free of charge since doing so forces private providers to recover the costs elsewhere. HWs noted that pregnant women often register at clinics late and some do not comply with the regularity of appointments for revisits, hence miss IPTp and other ANC services. HWs also noted some amplified rumours among clients regarding health risks and treatment failures of SP used during pregnancy, and together with clients' disappointment with waiting times and the sharing of cups at ANC clinics for SP, limit the uptake of IPTp-doses. HWs still question SP's treatment advantages and are confused about policy ambiguity on the recommended number of IPTp-SP doses and other IPTp-SP related guidelines. IPTp-SP uptake is further constrained by pregnant women's perceived health risks of taking SP and of poor service quality