A Selected Ion Flow Tube Study of the Reactions of Several Cations with the Group 6B Hexafluorides SF6, SeF6, and TeF6

The first investigation of the ion chemistry of SeF$_6$ and TeF$_6$ is presented. Using a selected ion flow tube, the thermal rate coefficients and ion product distributions have been determined at 300 K for the reactions of fourteen atomic and molecular cations, namely H$_3$O$^+$, CF$_3^+$, CF$^+$, CF$_2^+$, H$_2$O$^+$, N$_2$O$^+$, O$^+$, CO$_2^+$, CO$^+$, N$^+$, N$_2^+$, Ar$^+$, F$^+$ and Ne$^+$ (in order of increasing recombination energy), with SeF$_6$ and TeF$_6$. The results are compared with those from the reactions of these ions with SF$_6$, for which the reactions with CF$^+$, CF$_2^+$, N$_2$O$^+$ and F$^+$ are reported for the first time. Several distinct processes are observed amongst the large number of reactions studied, including dissociative charge transfer, and F$^-$, F, F$_2^-$ and F$_2$ abstraction from the neutral reactant molecule to the reagent ion. The dissociative charge transfer channels are discussed in relation to vacuum ultraviolet photoelectron and threshold photoelectron-photoion coincidence spectra of XF$_6$ (X = S, Se, and Te). For reagent ions whose recombination energies lie between the first dissociative ionisation limit, XF$_6$ $\rightarrow$ XF$_5^+$ + F + e$^-$, and the onset of ionisation of the XF$_6$ molecule, the results suggest that if dissociative charge transfer occurs, it proceeds via an intimate encounter. For those reagent ions whose recombination energies are greater than the onset of ionisation, long-range electron transfer may occur depending on whether certain physical factors apply, for example non-zero Franck-Condon overlap. From the reaction kinetics, limits for the heats of formation of SeF$_4$, SeF$_5$, TeF$_4$ and TeF$_5$ at 298 K have been obtained; $\Delta_f$H$^o$(SeF$_4$) < -369 kJ mol$^{-1}$, $\Delta_f$H$^o$(SeF$_5$) < -621 kJ mol$^{-1}$, $\Delta_f$H$^o$(TeF$_4$) > -570 kJ mol$^{-1}$, and $\Delta_f$H$^o$(TeF$_5$) < -822 kJ mol$^{-1}$

Report on Phase Two: The readiness to practise of NQSWs.

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Epidemiology of Injury in Women’s Super League Football: A Cohort Study

Introduction: The epidemiology of injury in male professional football has been well documented (Ekstrand, Hägglund, & Waldén, 2011) and used as a basis to understand injury trends for a number of years. The prevalence and incidence of injuries occurring in women’s super league football is unknown. The aim of this study is to estimate the prevalence and incidence of injury in an English Super League Women’s Football squad. Methods: Following ethical approval from Leeds Beckett University, players (n = 25) signed to a Women’s Super League Football club provided written informed consent to complete a self-administered injury survey. Measures of exposure, injury and performance over a 12-month period was gathered

The evolution of gregariousness in parasitoid wasps

Data are assembled on the clutch-size strategies adopted by extant species of parasitoid wasp. These data are used to reconstruct the history of clutch-size evolution in the group using a series of plausible evolutionary assumptions. Extant families are either entirely solitary, both solitary and gregarious, or else clutch size is unknown. Parsimony analysis suggests that the ancestors of most families were solitary, a result which is robust to different phylogenetic relationships and likely data inadequacies. This implies that solitariness was ubiquitous throughout the initial radiation of the group, and that transitions to gregariousness have subsequently occurred a minimum of 43 times in several, but not all lineages. Current data suggest that species-rich and small-bodied lineages are more likely to have evolved gregariousness, and contain more species with small gregarious brood sizes. I discuss the implications of these data for clutch-size theory

Detection of neopterin in the urine of captive and wild platyrrhines

Background: Non-invasive biomarkers can facilitate health assessments in wild primate populations by reducing the need for direct access to animals. Neopterin is a biomarker that is a product of the cell-mediated immune response, with high levels being indicative of poor survival expectations in some cases. The measurement of urinary neopterin concentration (UNC) has been validated as a method for monitoring cell-mediated immune system activation in multiple catarrhine species, but to date there is no study testing its utility in the urine of platyrrhine species. In this study, we collected urine samples across three platyrrhine families including small captive populations of Leontopithecus rosalia and Pithecia pithecia, and larger wild populations of Leontocebus weddelli, Saguinus imperator, Alouatta seniculus, and Plecturocebus toppini, to evaluate a commercial enzyme-linked immunosorbent assay (ELISA) for the measurement of urinary neopterin in platyrrhines. Results: Our results revealed measured UNC fell within the sensitivity range of the assay in all urine samples collected from captive and wild platyrrhine study species via commercial ELISA, and results from several dilutions met expectations. We found significant differences in the mean UNC across all study species. Most notably, we observed higher UNC in the wild population of L. weddelli which is known to have two filarial nematode infections compared to S. imperator, which only have one. Conclusion: Our study confirms that neopterin is measurable via commercial ELISA in urine collected from captive and wild individuals of six genera of platyrrhines across three different families. These findings promote the future utility of UNC as a promising biomarker for field primatologists conducting research in Latin America to non-invasively evaluate cell-mediated immune system activation from urine

Intestinal epithelial cells: at the interface of the microbiota and mucosal immunity.

The intestinal epithelium forms a barrier between the microbiota and the rest of the body. In addition, beyond acting as a physical barrier, the function of intestinal epithelial cells (IECs) in sensing and responding to microbial signals is increasingly appreciated and likely has numerous implications for the vast network of immune cells within and below the intestinal epithelium. IECs also respond to factors produced by immune cells, and these can regulate IEC barrier function, proliferation and differentiation, as well as influence the composition of the microbiota. The mechanisms involved in IEC-microbe-immune interactions, however, are not fully characterized. In this review, we explore the ability of IECs to direct intestinal homeostasis by orchestrating communication between intestinal microbes and mucosal innate and adaptive immune cells during physiological and inflammatory conditions. We focus primarily on the most recent findings and call attention to the numerous remaining unknowns regarding the complex crosstalk between IECs, the microbiota and intestinal immune cells

Validity of Arm-to-Arm BIA Devices Compared to DXA for Estimating %fat in College Men and Women

International Journal of Exercise Science 10(7): 977-988, 2017. Bioelectric impedance analysis (BIA) devices are commonly used to estimate percent body fat (%fat), although validation of their accuracy varies widely. The purpose of this study was to assess the validity of four commonly used BIA devices compared to dual-energy X-ray absorptiometry (DXA). College-aged men (n = 29, age = 19.7 ± 1.2 y, weight = 76.9 ± 12.5 kg) and women (n = 31, age = 20.5 ± 0.8 y, weight = 61.5 ± 9.2 kg) were evaluated for %fat using four single-frequency (50 mHz) BIA devices and DXA. A gender x device repeated measures ANOVA indicated some less expensive BIA devices produced %fat values that were not significantly different from DXA. A thumb-to-thumb BIA device produced the closest values in men (21.9 ± 6.6%) and women (32.1 ± 5.3%) compared to DXA (20.6 ± 6.1% and 30.3 ± 5.4%, respectively). The two more expensive BIA devices significantly underestimated in men (14.7 ± 5.8% and 17.0 ± 5.6%) and women (23.3 ± 4.2% and 23.3 ± 4.2%) compared to DXA. Interclass correlation coefficients with DXA were higher for the more expensive devices in men (ICC = 0.899 and 0.958) than the less expensive devices (ICC = 0.681 and 0.730). In women, all BIA devices showed moderate correlations with DXA (ICC = 0.537 to 0.658). Despite the convenience of simple BIA devices, their use in estimating body composition in young men and women might be questionable due to large variations in the differences between DXA and each device in this stud

An Analysis of an Alternate-Year Walleye Fry Stocking Program in the Cedar River in Iowa

Year-class analysis of walleye, Stizostedion v. vitreum (Mitchill), taken by anglers in a portion of the Cedar River in Iowa indicated that alternate-year stocking of 3,500 fry per mile of river did not influence year-class abundance. Despite the short duration of the project, 1951-1958, a reasonably direct relationship between spring floods and spring air temperatures and year-class abundance was evident. Disparity in year-class abundance between samples taken 5 miles apart and within 3 months of each other, but by different methods (angling and chemical kill), indicates either a sampling selectivity or a relative discreteness or stability of portions of an assumed homogeneous population of river walleyes, or both