Expression of The αβ T-Cell Receptor Is Necessary for The Generation of The Thymic Medulla

The architecture of the thymus of mice that congenitally fail to express the αβ T-cell receptor (TCRαβ) has been examined by immunohistology. In these mice, a defined mutation was introduced into the TCRc gene by homologous recombination. By using antibodies specific for cortical or medullary epithelium and for major histocompatibility complex antigens, the network of cortical epithelium in these mice was shown to be essentially unaltered in comparison with that of normal mice. In contrast, the thymic medulla was considerably reduced in size. This analysis shows that expression of the αβ TCR but not the γδ TCR is obligatory for establishing the thymic medulla and suggests that the growth of medullary epithelial cells may require contact with TCRαβ-expressing cells

Entrances and exits: changing perceptions of primary teaching as a career for men

Original article can be found at: http://www.informaworld.com/smpp/title~content=t713640830~db=all Copyright Informa / Taylor and Francis. DOI: 10.1080/03004430802352087The number of men in teaching has always been small, particularly in early childhood, but those that do come into teaching usually do so for the same reasons as women, namely enjoyment of working with children, of wanting to teach and wanting to make a difference to children's lives. However, in two separate studies, the authors have shown that on beginning teacher training in 1998, and at the point of leaving the profession in 2005, men and women tend to emphasise different concerns. This article will explore those differences and seek possible explanations for how men's views of teaching might be changing over time.Peer reviewe

Comparing the health and welfare of refugees and non-refugees at the outset of the COVID-19 pandemic: the results of a community needs assessment.

Refugees are a vulnerable population who experience significant health disparities. They may also be at disproportionately high risk of adverse outcomes due to the COVID-19 pandemic. This paper presents the results of a community needs assessment to investigate the impact of the pandemic on health and welfare in a refugee relocation community in the United States. A multilingual data collection team made up of refugees surveyed 179 participants (128 refugees vs. 51 non-refugees). Only 55.9% of refugee respondents said they would be able to provide enough food for their family this week, compared with 84.0% of non-refugees (p \u3c 0.01), and this difference was even greater for food next week (29.4% vs. 76.0%, p \u3c 0.01). A non-significantly smaller proportion of refugees reported knowing where to go if they were sick (69.1% vs. 81.6%, χ2 = 2.8, p = 0.10), and being able to get the medicine they need (75.0% vs. 87.8%, p = 0.07), while significantly fewer refugees reported feeling safe at home (72.8 vs. 87.8%, χ2 = 4.5, p = 0.04). Overall, refugees fared worse on nearly every measure. These findings should motivate further observational research and inform clinicians about the significant disparities in social determinants of health that refugees may experience during the pandemic

Optimizing parameters of an open-source airway segmentation algorithm using different CT images.

Background: Computed tomography (CT) helps physicians locate and diagnose pathological conditions. In some conditions, having an airway segmentation method which facilitates reconstruction of the airway from chest CT images can help hugely in the assessment of lung diseases. Many efforts have been made to develop airway segmentation algorithms, but methods are usually not optimized to be reliable across different CT scan parameters. Methods: In this paper, we present a simple and reliable semi-automatic algorithm which can segment tracheal and bronchial anatomy using the open-source 3D Slicer platform. The method is based on a region growing approach where trachea, right and left bronchi are cropped and segmented independently using three different thresholds. The algorithm and its parameters have been optimized to be efficient across different CT scan acquisition parameters. The performance of the proposed method has been evaluated on EXACT’09 cases and local clinical cases as well as on a breathing pig lung phantom using multiple scans and changing parameters. In particular, to investigate multiple scan parameters reconstruction kernel, radiation dose and slice thickness have been considered. Volume, branch count, branch length and leakage presence have been evaluated. A new method for leakage evaluation has been developed and correlation between segmentation metrics and CT acquisition parameters has been considered. Results: All the considered cases have been segmented successfully with good results in terms of leakage presence. Results on clinical data are comparable to other teams’ methods, as obtained by evaluation against the EXACT09 challenge, whereas results obtained from the phantom prove the reliability of the method across multiple CT platforms and acquisition parameters. As expected, slice thickness is the parameter affecting the results the most, whereas reconstruction kernel and radiation dose seem not to particularly affect airway segmentation. Conclusion: The system represents the first open-source airway segmentation platform. The quantitative evaluation approach presented represents the first repeatable system evaluation tool for like-for-like comparison between different airway segmentation platforms. Results suggest that the algorithm can be considered stable across multiple CT platforms and acquisition parameters and can be considered as a starting point for the development of a complete airway segmentation algorithm

Determination of a suitable low-dose abdominopelvic CT protocol using model-based iterative reconstruction through cadaveric study.

Introduction: Cadaveric studies provide a means of safely assessing new technologies and optimizing scanning prior to clinical validation. Reducing radiation exposure in a clinical setting can entail incremental dose reductions to avoid missing important clinical findings. The use of cadavers allows assessment of the impact of more substantial dose reductions on image quality. Our aim was to identify a suitable low‐dose abdominopelvic CT protocol for subsequent clinical validation. Methods: Five human cadavers were scanned at one conventional dose and three low‐dose settings. All scans were reconstructed using three different reconstruction algorithms: filtered back projection (FBP), hybrid iterative reconstruction (60% FBP and 40% adaptive statistical iterative reconstruction (ASIR40)), and model‐based iterative reconstruction (MBIR). Two readers rated the image quality both quantitatively and qualitatively. Results: Model‐based iterative reconstruction images had significantly better objective image noise and higher qualitative scores compared with both FBP and ASIR40 images at all dose levels. The greatest absolute noise reduction, between MBIR and FBP, of 34.3 HU (equating to a 68% reduction) was at the lowest dose level. MBIR reduced image noise and improved image quality even in CT images acquired with a mean radiation dose reduction of 62% compared with conventional dose studies reconstructed with ASIR40, with lower levels of objective image noise, superior diagnostic acceptability and contrast resolution, and comparable subjective image noise and streak artefact scores. Conclusion: This cadaveric study demonstrates that MBIR reduces image noise and improves image quality in abdominopelvic CT images acquired with dose reductions of up to 62%

Wet scavenging of soluble gases in DC3 deep convective storms using WRF-Chem simulations and aircraft observations

We examine wet scavenging of soluble trace gases in storms observed during the Deep Convective Clouds and Chemistry (DC3) field campaign. We conduct high-resolution simulations with the Weather Research and Forecasting model with Chemistry (WRF-Chem) of a severe storm in Oklahoma. The model represents well the storm location, size, and structure as compared with Next Generation Weather Radar reflectivity, and simulated CO transport is consistent with aircraft observations. Scavenging efficiencies (SEs) between inflow and outflow of soluble species are calculated from aircraft measurements and model simulations. Using a simple wet scavenging scheme, we simulate the SE of each soluble species within the error bars of the observations. The simulated SEs of all species except nitric acid (HNO_3) are highly sensitive to the values specified for the fractions retained in ice when cloud water freezes. To reproduce the observations, we must assume zero ice retention for formaldehyde (CH_2O) and hydrogen peroxide (H_2O_2) and complete retention for methyl hydrogen peroxide (CH_3OOH) and sulfur dioxide (SO_2), likely to compensate for the lack of aqueous chemistry in the model. We then compare scavenging efficiencies among storms that formed in Alabama and northeast Colorado and the Oklahoma storm. Significant differences in SEs are seen among storms and species. More scavenging of HNO_3 and less removal of CH_3OOH are seen in storms with higher maximum flash rates, an indication of more graupel mass. Graupel is associated with mixed-phase scavenging and lightning production of nitrogen oxides (NO_x), processes that may explain the observed differences in HNO_3 and CH_3OOH scavenging

Childhood bruising distribution observed from eight mechanisms of unintentional injury

Objective To inform the assessment of described mechanisms of bruising in children. Design Prospective cross-sectional study. Setting The emergency department, and children in the local community. Patients Children aged 0–13 years with bruises from unintentional injuries. Exclusions: bleeding disorder, medication affecting coagulation or child protection concerns. Interventions Injury incidents were categorised into one of eight causal mechanisms (fall from<1 m, 1–2 m, fall from standing height or less and hitting an object during fall, stairs or impact, crush, sports or motor vehicle collision). Main outcome measures Location, number and mechanism of bruising for each injury mechanism. Results 372 children had 559 injury incidents, resulting in 693 bruises; 85.2% of children were walking independently, with impact injuries and fall from standing height (including hitting an object) being the predominant mechanisms. A single bruise was observed in 81.7% of all incidents. Stair falls resulted in ≥3 bruises only with falls involving ≥10 steps (6/16). Bruising was rarely observed on the buttocks, upper arm, back of legs or feet. No bruises were seen in this dataset on ears, neck or genitalia. Petechial bruising was only noted in 1/293 unintentional incidents, involving a high-impact injury in a school-aged child. Conclusion These findings have the potential to aid an assessment of the plausibility of the explanation given for a child with bruising. Certain bruise distributions were rarely observed, namely multiple bruises from a single mechanism, petechiae and bruising to the ears, neck or genitalia

Benefits, Barriers and Enablers of Breastfeeding: Factor Analysis of Population Perceptions in Western Australia

Objective: The objective of this study was to investigate knowledge and community perceptions of breastfeeding in Western Australia using a factor analysis approach. Methods: Data were pooled from five Nutrition Monitoring Survey Series which included information on breastfeeding from 4,802 Western Australian adults aged 18–64 years. Tetrachoric factor analysis was conducted for data reduction and significant associations identified using logistic, ordinal and poisson regression analyses. Results: Four factors were derived for benefits (it’s natural, good nutrition, good for the baby, and convenience), barriers (breastfeeding problems, poor community acceptability, having to go back to work, and inconvenience) and for enablers (breastfeeding education, community support, family support and not having to work).As assessed by standardized odds ratios the most important covariates across benefit factors were: importance of breastfeeding (ORs range from 1.22–1.44),female gender (ORs range from 0.80 to 1.46), being able to give a time for how long a baby should be breastfed (ORs range from 0.96 to 1.27) and education (less than high school to university completion) (ORs range from 0.95 to 1.23); the most important covariate across barrier factors was being able to give a time for how long a baby should be breastfed (ORs range from 0.89 to 1.93); and the most important covariates across all enabling factors were education (ORs range from 1.14 to1.32) and being able to give a time for how long a baby should be breastfed (ORs range from 1.17 to 1.42).Conclusions: Being female, rating breastfeeding as important, believing that babies should be breastfed for a period of time and education accounted for most of the statistically significant associations. The differences between male and female perceptions require investigation particularly in relation to returning to work