Radiative Muon Capture on Hydrogen and the Induced Pseudoscalar Coupling

The first measurement of the elementary process $\mu^- p \rightarrow \nu_{\mu} n \gamma$ is reported. A photon pair spectrometer was used to measure the partial branching ratio ($2.10 \pm 0.22) \times 10^{-8}$ for photons of k > 60 MeV. The value of the weak pseudoscalar coupling constant determined from the partial branching ratio is $g_p(q^{2}=-0.88m_{\mu}^2) = (9.8 \pm 0.7 \pm 0.3) \cdot g_a(0)$, where the first error is the quadrature sum of statistical and systematic uncertainties and the second error is due to the uncertainty in $\lambda_{op}$, the decay rate of the ortho to para $p \mu p$ molecule. This value of g_p is $\sim$1.5 times the prediction of PCAC and pion-pole dominance.Comment: 13 pages, RevTeX type, 3 figures (encapsulated postscript), submitted to Phys. Rev. Let

Bacillus anthracis Lethal Toxin Disrupts TCR Signaling in CD1d-Restricted NKT Cells Leading to Functional Anergy

Exogenous CD1d-binding glycolipid (α-Galactosylceramide, α-GC) stimulates TCR signaling and activation of type-1 natural killer–like T (NKT) cells. Activated NKT cells play a central role in the regulation of adaptive and protective immune responses against pathogens and tumors. In the present study, we tested the effect of Bacillus anthracis lethal toxin (LT) on NKT cells both in vivo and in vitro. LT is a binary toxin known to suppress host immune responses during anthrax disease and intoxicates cells by protective antigen (PA)-mediated intracellular delivery of lethal factor (LF), a potent metalloprotease. We observed that NKT cells expressed anthrax toxin receptors (CMG-2 and TEM-8) and bound more PA than other immune cell types. A sub-lethal dose of LT administered in vivo in C57BL/6 mice decreased expression of the activation receptor NKG2D by NKT cells but not by NK cells. The in vivo administration of LT led to decreased TCR-induced cytokine secretion but did not affect TCR expression. Further analysis revealed LT-dependent inhibition of TCR-stimulated MAP kinase signaling in NKT cells attributable to LT cleavage of the MAP kinase kinase MEK-2. We propose that Bacillus anthracis–derived LT causes a novel form of functional anergy in NKT cells and therefore has potential for contributing to immune evasion by the pathogen

Work satisfaction of professional nurses in South Africa: a comparative analysis of the public and private sectors

<p>Abstract</p> <p>Background</p> <p>Work satisfaction of nurses is important, as there is sufficient empirical evidence to show that it tends to affect individual, organizational and greater health and social outcomes. Although there have been several studies of job satisfaction among nurses in South Africa, these are limited because they relate to studies of individual organizations or regions, use small samples or are dated. This paper presents a national study that compares and contrasts satisfaction levels of nurses in both public and private sectors.</p> <p>Methods</p> <p>This was a cross-sectional survey of professional nurses conducted throughout South Africa using a pretested and self-administered questionnaire. Univariate and bivariate statistical models were used to evaluate levels of satisfaction with various facets of work and to elicit the differences in satisfaction levels between different groups of nurses. A total of 569 professional nurses participated in the study.</p> <p>Results</p> <p>Private-sector nurses were generally satisfied, while public-sector nurses were generally dissatisfied. Public-sector nurses were most dissatisfied with their pay, the workload and the resources available to them. They were satisfied only with the social context of the work. Private-sector nurses were dissatisfied only with their pay and career development opportunities. Professional nurses in the more rural provinces, those intending to change sectors and those more likely not to be in their current positions within the next five years were also more likely to be dissatisfied with all facets of their work.</p> <p>Conclusion</p> <p>This study highlighted the overall dissatisfaction among South African nurses and confirmed the disparity between the levels of job satisfaction between the public and private sectors. Health managers should address those factors that affect job satisfaction, and therefore retention, of nurses in South Africa. Improving the work environment so that it provides a context congruent with the aspirations and values systems of nurses is more likely to increase the satisfaction of nurses and consequently have a positive effect on individual, organizational and health outcomes.</p

"The post-antibiotic apocalypse" and the "war on superbugs": catastrophe discourse in microbiology, its rhetorical form and political function

Discourses evoking an antibiotic apocalypse and a war on superbugs are emerging just at a time when so-called "catastrophe discourses" are undergoing critical and reflexive scrutiny in the context of global warming and climate change. This article combines insights from social science research into climate change discourses with applied metaphor research based on recent advances in cognitive linguistics, especially with relation to "discourse metaphors." It traces the emergence of a new apocalyptic discourse in microbiology and health care, examines its rhetorical and political function and discusses its advantages and disadvantages. It contains a reply by the author of the central discourse metaphor, "the post-antibiotic apocalypse," examined in the article

Human C. difficile toxin–specific memory B cell repertoires encode poorly neutralizing antibodies

Clostridioides difficile is a leading cause of nosocomial infection responsible for significant morbidity and mortality with limited options for therapy. Secreted C. difficile toxin B (TcdB) is a major contributor to disease pathology, and select TcdB-specific Abs may protect against disease recurrence. However, the high frequency of recurrence suggests that the memory B cell response, essential for new Ab production following C. difficile reexposure, is insufficient. We therefore isolated TcdB-specific memory B cells from individuals with a history of C. difficile infection and performed single-cell deep sequencing of their Ab genes. Herein, we report that TcdB-specific memory B cell–encoded antibodies showed somatic hypermutation but displayed limited isotype class switch. Memory B cell–encoded mAb generated from the gene sequences revealed low to moderate affinity for TcdB and a limited ability to neutralize TcdB. These findings indicate that memory B cells are an important factor in C. difficile disease recurrence