Scattering of high-energy positrons from protons

Positron and electron beams from the Stanford Mark III linear accelerator have been used to investigate the importance of two-photon exchanges in electron scattering from the proton. The scattering cross sections for positrons and electrons have been compared at 200 and 300 MeV for q^2 (the square of the four-momentum transfer) from 0.3 to 5.2 F^-2. The results show no evidence of anomalous two-photon effects and verify the correctness of the first Born approximation form factor analysis to within a few percent or better for this range of q^2. The variation of the cross sections with q^2 has also been measured with high accuracy. The specific ionizations of 300-MeV positrons and electrons in hydrogen at one atmosphere have been compared in the course of the experiment, and found to be equal to within ±0.3%

Scattering of 300-MeV positrons from cobalt and bismuth

Positrons and electrons from the Stanford Mark III linear accelerator have been scattered from cobalt and bismuth at 300 MeV. The ratio R, equal to (σ--σ+)/(σ-+σ+), has been measured at a number of angles from 10° to 45° for cobalt and from 5° to 45° for bismuth. Two experiments are reported: a high-percision experiment with poor energy resolution, suitable for measuring the small values of R found at small angles, where inelastic scattering is not important; and an experiment with somewhat lower precision but better energy resolution, suitable for measuring the larger values of R found at angles where inelastic scattering must be taken into account. The elastic scattering data are in good agreement with phase-shift calculations of Herman, Clark, and Ravenhall, who used nuclear charge distributions which fit earlier electron scattering data. The inelastic data, for which no reliable predictions exist, indicate that Rinelastic is generally smaller than Relastic. This suggests that the inelastic scattering is better described by the first Born approximation, in which R=0, than is the elastic scattering

Responsiveness of PROMIS® to change in chronic obstructive pulmonary disease.

BackgroundChronic obstructive pulmonary disease (COPD) is a progressive chronic disease characterized by airflow obstruction that leads to shortness of breath and substantial negative impacts on health-related quality of life (HRQL). The course of COPD includes periodic acute exacerbations that require changes in treatment and/or hospitalizations. This study was designed to examine the responsiveness of Patient-Reported Outcomes Measurement Information System® (PROMIS®) measures to changes associated with COPD exacerbation recovery.MethodsA longitudinal analysis using mixed-effects models was conducted of people who were enrolled while stable (n = 100) and those who experienced an acute exacerbation (n = 85). PROMIS (physical function, pain interference, pain behavior, fatigue, anxiety, depression, anger, social roles, discretionary social activities, Global Health, dyspnea severity and dyspnea functional limitations) and COPD-targeted HRQL measures were completed at baseline and at 12 weeks.ResultsWe administered PROMIS measures using computer adaptive testing (CAT), followed by administration of any remaining short form (SF) items that had not yet been administered by CAT. Examination of the difference between group differences from baseline to 12 weeks in the stable and exacerbation groups revealed that the exacerbation group changed (improved) significantly more than the stable group in anxiety (p < .001 to p < .01; f2 effect size [ES] = 0.023/0.021), fatigue (p < .0001; ES = 0.036/0.047) and social roles (p < .001 to p < .05; ES = 0.035/0.024). All effect sizes were small in magnitude and smaller than hypothesized. Depression was also statistically significant (p < .05, SF only) but the ES was trivial. For all other PROMIS domains, the differences were not significant and ES were trivial.ConclusionsThis longitudinal study provides some support for the validity of the PROMIS fatigue, anxiety, and social roles domains in COPD, but further evaluation of responsiveness is warranted

The consequences of early childhood growth failure over the life course:

This paper examines the impact over the life course of early childhood growth failure as measured by achieved height at 36 months. It uses data collected on individuals who participated in a nutritional supplementation trial between 1969 and 1977 in rural Guatemala and who were subsequently reinterviewed between 2002 and 2004. It finds that individuals who did not suffer growth failure in the first three years of life complete more schooling, score higher on tests of cognitive skill in adulthood, have better outcomes in the marriage market, earn higher wages and are more likely to be employed in higher-paying skilled labor and white-collar jobs, are less likely to live in poor households, and, for women, fewer pregnancies and smaller risk of miscarriages and stillbirths. Growth failure has adverse impacts on body size and several dimensions of physical fitness in adulthood but does not have marked effects on risk indicators of cardiovascular and related chronic diseases. These results provide a powerful rationale for investments that reduce early-life growth failure.Chronic disease, early life growth failure, fertility, Human capital, Poverty, Undernutrition, Wages,

Dynamic Fracture and Crack Arrest Toughness Evaluation of High-Performance Steel Used in Highway Bridges

Impact energy tests are an efficient method of verifying adequate toughness of steel prior to it being put into service. Based on a multitude of historical correlations between impact energy and fracture toughness, minimum impact energy requirements that correspond to desired levels of fracture toughness are prescribed by steel bridge design specifications. Research characterizing the fracture behavior of grade 485 and 690 (70 and 100) high-performance steel utilized impact, fracture toughness, and crack arrest testing to verify adequate performance for bridge applications. Fracture toughness results from both quasi-static and dynamic stress intensity rate tests were analyzed using the most recently adopted master curve methodology. Both impact and fracture toughness tests indicated performance significantly greater than the minimum required by material specifications. Even at the AASHTO Zone III service temperature, which is significantly colder than prescribed test temperatures, minimum average impact energy requirements were greatly exceeded. All master curve reference temperatures, both for quasi-static and dynamic loading rates, were found to be colder than the Zone III minimum service temperature. Three correlations between impact energy and fracture toughness were evaluated and found to estimate reference temperatures that are conservative by 12 to 50 °C (22 to 90 °F) on average for the grades and specimen types tested. The evaluation of two reference temperature shifts intended to account for the loading rate was also performed and the results are discussed

Structural correlates of antimicrobial efficacy in IL-8 and related human kinocidins

AbstractChemokines are small (8–12 kDa) effector proteins that potentiate leukocyte chemonavigation. Beyond this role, certain chemokines have direct antimicrobial activity against human pathogenic organisms; such molecules are termed kinocidins. The current investigation was designed to explore the structure–activity basis for direct microbicidal activity of kinocidins. Amino acid sequence and 3-dimensional analyses demonstrated these molecules to contain iterations of the conserved γ-core motif found in broad classes of classical antimicrobial peptides. Representative CXC, CC and C cysteine-motif-group kinocidins were tested for antimicrobial activity versus human pathogenic bacteria and fungi. Results demonstrate that these molecules exert direct antimicrobial activity in vitro, including antibacterial activity of native IL-8 and MCP-1, and microbicidal activity of native IL-8. To define molecular determinants governing its antimicrobial activities, the IL-8 γ-core (IL-8γ) and α-helical (IL-8α) motifs were compared to native IL-8 for antimicrobial efficacy in vitro. Microbicidal activity recapitulating that of native IL-8 localized to the autonomous IL-8α motif in vitro, and demonstrated durable microbicidal activity in human blood and blood matrices ex vivo. These results offer new insights into the modular architecture, context-related deployment and function, and evolution of host defense molecules containing γ-core motifs and microbicidal helices associated with antimicrobial activity

Pterodactyl: Trade Study for an Integrated Control System Design of a Mechanically Deployable Entry Vehicle

This paper presents the trade study method used to evaluate and downselect from a set of guidance and control (G&C) system designs for a mechanically Deployable Entry Vehicle (DEV). The Pterodactyl project was prompted by the challenge to develop an effective G&C system for a vehicle without a backshell, which is the case for DEVs. For the DEV, the project assumed a specific aeroshell geometry pertaining to an Adaptable, Deployable Entry and Placement Technology (ADEPT) vehicle, which was successfully developed by NASAs Space Technology Mission Directorate (STMD) prior to this study. The Pterodactyl project designed three different entry G&C systems for precision targeting. This paper details the Figures of Merit (FOMs) and metrics used during the course of the projects G&C system assessment. The relative importance of the FOMs was determined from the Analytic Hierarchy Process (AHP), which was used to develop weights that were combined with quantitative design metrics and engineering judgement to rank the G&C systems against one another. This systematic method takes into consideration the projects input while simultaneously reducing unintentional judgement bias and ultimately was used to select a single G&C design for the project to pursue in the next design phase

Chemoproteomics reveals Toll-like receptor fatty acylation

Partial funding for Open Access provided by The Ohio State University Open Access Fund.Background: Palmitoylation is a 16-carbon lipid post-translational modification that increases protein hydrophobicity. This form of protein fatty acylation is emerging as a critical regulatory modification for multiple aspects of cellular interactions and signaling. Despite recent advances in the development of chemical tools for the rapid identification and visualization of palmitoylated proteins, the palmitoyl proteome has not been fully defined. Here we sought to identify and compare the palmitoylated proteins in murine fibroblasts and dendritic cells. Results: A total of 563 putative palmitoylation substrates were identified, more than 200 of which have not been previously suggested to be palmitoylated in past proteomic studies. Here we validate the palmitoylation of several new proteins including Toll-like receptors (TLRs) 2, 5 and 10, CD80, CD86, and NEDD4. Palmitoylation of TLR2, which was uniquely identified in dendritic cells, was mapped to a transmembrane domain-proximal cysteine. Inhibition of TLR2 S-palmitoylation pharmacologically or by cysteine mutagenesis led to decreased cell surface expression and a decreased inflammatory response to microbial ligands. Conclusions: This work identifies many fatty acylated proteins involved in fundamental cellular processes as well as cell type-specific functions, highlighting the value of examining the palmitoyl proteomes of multiple cell types. Spalmitoylation of TLR2 is a previously unknown immunoregulatory mechanism that represents an entirely novel avenue for modulation of TLR2 inflammatory activity.This work was supported by funding from the NIH/NIAID (grant R00AI095348 to J.S.Y.), the NIH/NIGMS (R01GM087544 to HCH), and the Ohio State University Public Health Preparedness for Infectious Diseases (PHPID) program. NMC is supported by the Ohio State University Systems and Integrative Biology Training Program (NIH/NIGMS grant T32GM068412). BWZ is a fellow of the National Science Foundation Graduate Research Fellowship Program (DGE-0937362)