169 research outputs found

    Two-Loop Polarization Contributions to Radiative-Recoil Corrections to Hyperfine Splitting in Muonium

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    We calculate radiative-recoil corrections of order α2(Zα)(m/M)EF\alpha^2(Z\alpha)(m/M)E_F to hyperfine splitting in muonium generated by the diagrams with electron and muon polarization loops. These corrections are enhanced by the large logarithm of the electron-muon mass ratio. The leading logarithm cubed and logarithm squared contributions were obtained a long time ago. The single-logarithmic and nonlogarithmic contributions calculated here improve the theory of hyperfine splitting, and affect the value of the electron-muon mass ratio extracted from the experimental data on the muonium hyperfine splitting.Comment: 15 pages, 11 figure

    Transactivation of EGFR by LPS induces COX-2 expression in enterocytes

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    Necrotizing enterocolitis (NEC) is the leading cause of gastrointestinal morbidity and mortality in preterm infants. NEC is characterized by an exaggerated inflammatory response to bacterial flora leading to bowel necrosis. Bacterial lipopolysaccharide (LPS) mediates inflammation through TLR4 activation and is a key molecule in the pathogenesis of NEC. However, LPS also induces cyclooxygenase-2 (COX-2), which promotes intestinal barrier restitution through stimulation of intestinal cell survival, proliferation, and migration. Epidermal growth factor receptor (EGFR) activation prevents experimental NEC and may play a critical role in LPS-stimulated COX-2 production. We hypothesized that EGFR is required for LPS induction of COX-2 expression. Our data show that inhibiting EGFR kinase activity blocks LPS-induced COX-2 expression in small intestinal epithelial cells. LPS induction of COX-2 requires Src-family kinase signaling while LPS transactivation of EGFR requires matrix metalloprotease (MMP) activity. EGFR tyrosine kinase inhibitors block LPS stimulation of mitogen-activated protein kinase ERK, suggesting an important role of the MAPK/ERK pathway in EGFR-mediated COX-2 expression. LPS stimulates proliferation of IEC-6 cells, but this stimulation is inhibited with either the EGFR kinase inhibitor AG1478, or the selective COX-2 inhibitor Celecoxib. Taken together, these data show that EGFR plays an important role in LPS-induction of COX-2 expression in enterocytes, which may be one mechanism for EGF in inhibition of NEC

    Evaluation of Staphylococcus aureus Nasal Carriage Screening before Vascular Surgery

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    INTRODUCTION: Staphylococcus aureus is the most important pathogen in the development of surgical site infections (SSI). Patients who carry S. aureus in the nose are at increased risk for the development of SSI in cardiothoracic and orthopedic surgery. In these populations it has been shown that the risk for SSI can be substantially reduced by eradicating S. aureus carriage. For vascular surgery the relation between nasal carriage and surgical site infections has not been clearly investigated. For this reason we performed this study to analyze the relation between S. aureus nasal carriage and SSI in our vascular surgery population. METHODS: A prospective cohort study was undertaken, including all patients undergoing vascular surgery between January first 2010 and December 31th 2010. Before surgery patients were screened for S. aureus nasal carriage using a PCR technique. The presence of SSI was recorded based on criteria of the CDC. RESULTS: Screening was performed in 224. Of those, 55 (24.5%) were positive, 159 (71.0%) were negative and 10 (4.5%) were inconclusive. In the screened vascular population 4 S. aureus SSI occurred in the 55 carriers compared with 6 in 159 non-carriers (p=0.24). A stratified analysis revealed a 10-fold increased risk in nasal carriers undergoing central reconstruction surgery (3 S. aureus SSI in 20 procedures versus 1 in 65 procedures in non-carriers, p=0.039). DISCUSSION: In patients undergoing central reconstruction surgery nasals carriers are at increased risk for the development of S. aureus SSI. These patients will probably benefit from perioperative treatment to eradicate nasal carriage

    Occupational exposure to gases/fumes and mineral dust affect DNA methylation levels of genes regulating expression

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    Many workers are daily exposed to occupational agents like gases/fumes, mineral dust or biological dust, which could induce adverse health effects. Epigenetic mechanisms, such as DNA methylation, have been suggested to play a role. We therefore aimed to identify differentially methylated regions (DMRs) upon occupational exposures in never-smokers and investigated if these DMRs associated with gene expression levels. To determine the effects of occupational exposures independent of smoking, 903 never-smokers of the LifeLines cohort study were included. We performed three genome-wide methylation analyses (Illumina 450 K), one per occupational exposure being gases/fumes, mineral dust and biological dust, using robust linear regression adjusted for appropriate confounders. DMRs were identified using comb-p in Python. Results were validated in the Rotterdam Study (233 never-smokers) and methylation-expression associations were assessed using Biobank-based Integrative Omics Study data (n = 2802). Of the total 21 significant DMRs, 14 DMRs were associated with gases/fumes and 7 with mineral dust. Three of these DMRs were associated with both exposures (RPLP1 and LINC02169 (2x)) and 11 DMRs were located within transcript start sites of gene expression regulating genes. We replicated two DMRs with gases/fumes (VTRNA2-1 and GNAS) and one with mineral dust (CCDC144NL). In addition, nine gases/fumes DMRs and six mineral dust DMRs significantly associated with gene expression levels. Our data suggest that occupational exposures may induce differential methylation of gene expression regulating genes and thereby may induce adverse health effects. Given the millions of workers that are exposed daily to occupational exposures, further studies on this epigenetic mechanism and health outcomes are warranted

    Psychometric properties of the mock interview rating scale for schizophrenia and other serious mental illnesses

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    BackgroundOver the past 10 years, job interview training has emerged as an area of study among adults with schizophrenia and other serious mental illnesses who face significant challenges when navigating job interviews. The field of mental health services research has limited access to assessments of job interview skills with rigorously evaluated psychometric properties.ObjectiveWe sought to evaluate the initial psychometric properties of a measure assessing job interview skills via role-play performance.MethodsAs part of a randomized controlled trial, 90 adults with schizophrenia or other serious mental illnesses completed a job interview role-play assessment with eight items (and scored using anchors) called the mock interview rating scale (MIRS). A classical test theory analysis was conducted including confirmatory factor analyses, Rasch model analysis and calibration, and differential item functioning; along with inter-rater, internal consistency, and test-retest reliabilities. Pearson correlations were used to evaluate construct, convergent, divergent, criterion, and predictive validity by correlating the MIRS with demographic, clinical, cognitive, work history measures, and employment outcomes.ResultsOur analyses resulted in the removal of a single item (sounding honest) and yielded a unidimensional total score measurement with support for its inter-rater reliability, internal consistency, and test-retest reliability. There was initial support for the construct, convergent, criterion, and predictive validities of the MIRS, as it correlated with measures of social competence, neurocognition, valuing job interview training, and employment outcomes. Meanwhile, the lack of correlations with race, physical health, and substance abuse lent support for divergent validity.ConclusionThis study presents initial evidence that the seven-item version of the MIRS has acceptable psychometric properties supporting its use to assess job interview skills reliably and validly among adults with schizophrenia and other serious mental illnesses.Clinical Trial RegistrationNCT03049813

    Theory of Light Hydrogenlike Atoms

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    The present status and recent developments in the theory of light hydrogenic atoms, electronic and muonic, are extensively reviewed. The discussion is based on the quantum field theoretical approach to loosely bound composite systems. The basics of the quantum field theoretical approach, which provide the framework needed for a systematic derivation of all higher order corrections to the energy levels, are briefly discussed. The main physical ideas behind the derivation of all binding, recoil, radiative, radiative-recoil, and nonelectromagnetic spin-dependent and spin-independent corrections to energy levels of hydrogenic atoms are discussed and, wherever possible, the fundamental elements of the derivations of these corrections are provided. The emphasis is on new theoretical results which were not available in earlier reviews. An up-to-date set of all theoretical contributions to the energy levels is contained in the paper. The status of modern theory is tested by comparing the theoretical results for the energy levels with the most precise experimental results for the Lamb shifts and gross structure intervals in hydrogen, deuterium, and helium ion He+He^+, and with the experimental data on the hyperfine splitting in muonium, hydrogen and deuterium.Comment: 230 pages, 106 figures, 24 tables. Discussion of muonic hydrogen is added, list of references expanded, some minor corrections and amendment

    Psychometric properties of the mock interview rating scale for autistic transition-age youth

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    BackgroundEmployment is a major contributor to quality of life. However, autistic people are often unemployed and underemployed. One potential barrier to employment is the job interview. However, the availability of psychometrically-evaluated assessments of job interviewing skills is limited for autism services providers and researchers.ObjectiveWe analyzed the psychometric properties of the Mock Interview Rating Scale that was adapted for research with autistic transition-age youth (A-MIRS; a comprehensive assessment of video-recorded job interview role-play scenarios using anchor-based ratings for 14 scripted job scenarios).MethodsEighty-five transition-age youth with autism completed one of two randomized controlled trials to test the effectiveness of two interventions focused on job interview skills. All participants completed a single job interview role-play at pre-test that was scored by raters using the A-MIRS. We analyzed the structure of the A-MIRS using classical test theory, which involved conducting both exploratory and confirmatory factor analyzes, Rasch model analysis and calibration techniques. We then assessed internal consistency, inter-rater reliability, and test–retest reliability. Pearson correlations were used to assess the A-MIRS’ construct, convergent, divergent, criterion, and predictive validities by comparing it to demographic, clinical, cognitive, work history measures, and employment outcomes.ResultsResults revealed an 11-item unidimensional construct with strong internal consistency, inter-rater reliability, and test–retest reliability. Construct [pragmatic social skills (r = 0.61, p < 0.001), self-reported interview skills (r = 0.34, p = 0.001)], divergent [e.g., age (r = −0.13, p = 0.26), race (r = 0.02, p = 0.87)], and predictive validities [competitive employment (r = 0.31, p = 0.03)] received initial support via study correlations, while convergent [e.g., intrinsic motivation (r = 0.32, p = 0.007), job interview anxiety (r = −0.19, p = 0.08)] and criterion [e.g., prior employment (r = 0.22, p = 0.046), current employment (r = 0.21, p = 0.054)] validities were limited.ConclusionThe psychometric properties of the 11-item A-MIRS ranged from strong-to-acceptable, indicating it may have utility as a reliable and valid method for assessing the job interview skills of autistic transition-age youth
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