289 research outputs found

    Direct, on-the-fly calculation of unresolved resonance region cross sections in Monte Carlo simulations

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    The theory, implementation, and testing of a method for on-the-fly unresolved resonance region cross section calculations in continuous-energy Monte Carlo neutron transport codes are presented. With this method, each time that a cross section value is needed within the simulation, a realization of unresolved resonance parameters is generated about the desired energy and temperature-dependent single-level Breit-Wigner resonance cross sections are computed directly via use of the analytical ψ − χ Doppler integrals. Results indicate that, in room-temperature simulations of a system that is known to be highly sensitive to the effects of resonance structure in unresolved region cross sections, the on-the-fly treatment produces results that are in excellent agreement with those produced with the well-established probability table method. Additionally, similar agreement is observed between results obtained from the on-the-fly and probability table methods for another intermediate spectrum system at temperatures of 293.6 K and 2500 K. With relatively tight statistical uncertainties at the ∼ 10 pcm level, all on-the-fly and probability table keff eigenvalues agree to within 2σ. Also, we use the on-the-fly approach to show that accounting for the resonance structure of competitive reaction cross sections can have non-negligible effects for intermediate/fast spectrum systems. Biases of up to 90 pcm are observed. Finally, the consequences of the on-the-fly method with respect to simulation runtime and memory requirements are briefly discussed.United States. Department of Energy (Consortium for Advanced Simulation of Light Water Reactors. Contract DE-AC05-00OR22725

    Nuclease Modulates Biofilm Formation in Community-Associated Methicillin-Resistant Staphylococcus aureus

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    Community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) is an emerging contributor to biofilm-related infections. We recently reported that strains lacking sigma factor B (sigB) in the USA300 lineage of CA-MRSA are unable to develop a biofilm. Interestingly, when spent media from a USA300 sigB mutant was incubated with other S. aureus strains, biofilm formation was inhibited. Following fractionation and mass spectrometry analysis, the major anti-biofilm factor identified in the spent media was secreted thermonuclease (Nuc). Considering reports that extracellular DNA (eDNA) is an important component of the biofilm matrix, we investigated the regulation and role of Nuc in USA300. The expression of the nuc gene was increased in a sigB mutant, repressed by glucose supplementation, and was unaffected by the agr quorum-sensing system. A FRET assay for Nuc activity was developed and confirmed the regulatory results. A USA300 nuc mutant was constructed and displayed an enhanced biofilm-forming capacity, and the nuc mutant also accumulated more high molecular weight eDNA than the WT and regulatory mutant strains. Inactivation of nuc in the USA300 sigB mutant background partially repaired the sigB biofilm-negative phenotype, suggesting that nuc expression contributes to the inability of the mutant to form biofilm. To test the generality of the nuc mutant biofilm phenotypes, the mutation was introduced into other S. aureus genetic backgrounds and similar increases in biofilm formation were observed. Finally, using multiple S. aureus strains and regulatory mutants, an inverse correlation between Nuc activity and biofilm formation was demonstrated. Altogether, our findings confirm the important role for eDNA in the S. aureus biofilm matrix and indicates Nuc is a regulator of biofilm formation

    Net neutrality discourses: comparing advocacy and regulatory arguments in the United States and the United Kingdom

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    Telecommunications policy issues rarely make news, much less mobilize thousands of people. Yet this has been occurring in the United States around efforts to introduce "Net neutrality" regulation. A similar grassroots mobilization has not developed in the United Kingdom or elsewhere in Europe. We develop a comparative analysis of U.S. and UK Net neutrality debates with an eye toward identifying the arguments for and against regulation, how those arguments differ between the countries, and what the implications of those differences are for the Internet. Drawing on mass media, advocacy, and regulatory discourses, we find that local regulatory precedents as well as cultural factors contribute to both agenda setting and framing of Net neutrality. The differences between national discourses provide a way to understand both the structural differences between regulatory cultures and the substantive differences between policy interpretations, both of which must be reconciled for the Internet to continue to thrive as a global medium

    Net neutrality discourses: comparing advocacy and regulatory arguments in the United States and the United Kingdom

    Get PDF
    Telecommunications policy issues rarely make news, much less mobilize thousands of people. Yet this has been occurring in the United States around efforts to introduce "Net neutrality" regulation. A similar grassroots mobilization has not developed in the United Kingdom or elsewhere in Europe. We develop a comparative analysis of U.S. and UK Net neutrality debates with an eye toward identifying the arguments for and against regulation, how those arguments differ between the countries, and what the implications of those differences are for the Internet. Drawing on mass media, advocacy, and regulatory discourses, we find that local regulatory precedents as well as cultural factors contribute to both agenda setting and framing of Net neutrality. The differences between national discourses provide a way to understand both the structural differences between regulatory cultures and the substantive differences between policy interpretations, both of which must be reconciled for the Internet to continue to thrive as a global medium

    Plasmid-based transient human stromal cell-derived factor-1 gene transfer improves cardiac function in chronic heart failure

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    We previously demonstrated that transient stromal cell-derived factor-1 alpha (SDF-1) improved cardiac function when delivered via cell therapy in ischemic cardiomyopathy at a time remote from acute myocardial infarction (MI) rats. We hypothesized that non-viral gene transfer of naked plasmid DNA-expressing hSDF-1 could similarly improve cardiac function. To optimize plasmid delivery, we tested SDF-1 and luciferase plasmids driven by the cytomegalovirus (CMV) promoter with (pCMVe) or without (pCMV) translational enhancers or α myosin heavy chain (pMHC) promoter in a rodent model of heart failure. In vivo expression of pCMVe was 10-fold greater than pCMV and pMHC expression and continued over 30 days. We directly injected rat hearts with SDF-1 plasmid 1 month after MI and assessed heart function. At 4 weeks after plasmid injection, we observed a 35.97 and 32.65% decline in fractional shortening (FS) in control (saline) animals and pMHC-hSDF1 animals, respectively, which was sustained to 8 weeks. In contrast, we observed a significant 24.97% increase in animals injected with the pCMVe-hSDF1 vector. Immunohistochemistry of cardiac tissue revealed a significant increase in vessel density in the hSDF-1-treated animals compared with control animals. Increasing SDF-1 expression promoted angiogenesis and improved cardiac function in rats with ischemic heart failure along with evidence of scar remodeling with a trend toward decreased myocardial fibrosis. These data demonstrate that stand-alone non-viral hSDF-1 gene transfer is a strategy for improving cardiac function in ischemic cardiomyopathy

    Perception and Impact of COVID-19 Pandemic in Psoriasis Patients: Data from the German PsoBest and the CoronaBest Registries

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    María José Valencia López,1,* Brigitte Stephan,1,* Anna Meineke,1 Sandra Wolf,1 Diamant Thaci,2 Ulrich Mrowietz,3 Valerie Andrees,1 Stephan Jeff Rustenbach,1 Kristian Reich,1 Linus Thalmann,1 Henriette Bogena,1 Petra Staubach,4 Ralph Michael von Kiedrowski,5 Matthias Augustin1 1Institute for Health Services Research in Dermatology and Nursing (IVDP), University Medical Center Hamburg-Eppendorf (UKE), Hamburg, Germany; 2Institute and Comprehensive Center for Inflammation Medicine, University of Lübeck, Lübeck, Germany; 3Psoriasis-Center, Department of Dermatology, University Medical Center Schleswig-Holstein, Kiel, Germany; 4Department of Dermatology and Allergy, University Medical Center Mainz, Mainz, Germany; 5Dermatological Practice Selters, Selters, Germany*These authors contributed equally to this workCorrespondence: Matthias Augustin, Institute for Health Services Research in Dermatology and Nursing (IVDP), University Medical Center Hamburg-Eppendorf (UKE), Martinistraße 52, Hamburg, 20246, Germany, Tel +49 040 7410 55428, Fax +49 040 7410 55348, Email [email protected]: Limited data are available characterizing the impact of the SARS-CoV-2 pandemic on psoriasis care for patients in Germany.Objective: To analyze patient perception and impact of the pandemic on well-being and psoriasis management of German patients with moderate-to-severe psoriasis or psoriasis arthritis under systemic therapies.Methods: The CoronaBest registry captures events of SARS-CoV-2 infections and analyzes the impact of the pandemic on patients with psoriasis or psoriasis arthritis. In June 2020, and independently in February 2022, patients with psoriasis or psoriasis arthritis received a standardized questionnaire for current treatment, protective measures, well-being, and individual risks for COVID-19, among others.Results: Included were 4,194 patients in 2020 (mean age of 47.7 years and 41.8% women) and 4,818 patients in 2022 (mean age of 56.4 and 42.9% women). Treatment discontinuations were observed in 2.7% and 1.7% of patients in 2020 and 2022, respectively. In the vast majority of the cases (> 92%), no additional measures were taken concerning the management of psoriasis treatments in either 2020 or 2022. Those patients with changes reported most frequently: telephone calls instead of face-to-face visits (80.2%, in 2020 vs 40.5% in 2022) or more frequent controls (27.1%, 2020 vs 22.0%, 2022). A majority (66.7%, 2020, and 70.6%, 2022) did not perceive the virus as a considerable threat. The proportion of patients feeling well informed about COVID-19 by physicians increased from 42.6% in 2020 to 51.8% in 2022. About 81.1% of patients in 2020 and 67.5% in 2022 stated that their overall personal condition was not affected due to the pandemic. Physicians attributed no special risk of contracting SARS-CoV-2 in most of the patients.Conclusion: A high rate of systemic treatment persistence and awareness of risks and protective measures indicate that health care for psoriasis largely followed current national and international recommendations during the COVID-19 pandemic.Keywords: psoriasis, COVID-19, SARS-CoV-2, pandemic, patient perception, risk factor

    Direct Determination of Absolute Molecular Stereochemistry in Gas Phase by Coulomb Explosion Imaging

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    Bijvoet’s method, which makes use of anomalous x-ray diffraction or dispersion, is the standard means of directly determining the absolute (stereochemical) configuration of molecules, but it requires crystalline samples and often proves challenging in structures exclusively comprising light atoms. Herein, we demonstrate a mass spectrometry approach that directly images the absolute configuration of individual molecules in the gas phase by cold target recoil ion momentum spectroscopy after laser ionization–induced Coulomb explosion. This technique is applied to the prototypical chiral molecule bromochlorofluoromethane and the isotopically chiral methane derivative bromodichloromethane

    Clinical Utilization Pattern of Liquid Biopsies (LB) to Detect Actionable Driver Mutations, Guide Treatment Decisions and Monitor Disease Burden During Treatment of 33 Metastatic Colorectal Cancer (mCRC) Patients (pts) at a Fox Chase Cancer Center GI Oncology Subspecialty Clinic

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    Background: Liquid biopsy (LB) captures dynamic genomic alterations (alts) across metastatic colorectal cancer (mCRC) therapy and may complement tissue biopsy (TB). We sought to describe the utility of LB and better understand mCRC biology during therapy.Methods: Thirty-three patients (pts) with mCRC underwent LB. We used permutation-based t-tests to assess associations between alts, and clinical variables and used Kendall's tau to measure correlations.Results: Of 33 pts, 15 were women; 22 had colon, and the rest rectal cancer. Pts received a median of two lines of therapy before LB. Nineteen pts had limited testing on TB (RAS/RAF/TP53/APC), 11 extended NGS, and 3 no TB. Maxpct and alts correlated with CEA (p < 0.001, respectively). In 3/5 pts with serial LB, CEA correlated with maxpct trend, and CT tumor burden. In 6 pts, mutant RAS was seen in LB and not TB; 5/6 had received anti-EGFR therapy prior to LB, suggesting RAS alts developed post-therapy. In two pts RAS-mutated by TB, no RAS alts were detected on LB; these pts had low disease burden on CT at time of LB that also did not reveal APC or TP53 alts. In six patients who were KRAS wt based on TB, post anti-EGFR LB revealed subclonal KRAS mutations, likely a treatment effect. The median number of alts was higher post anti-EGFR LB (n = 12) vs. anti-EGFR naïve LB (n = 22) (9.5 vs. 5.5, p = 0.059) but not statistically significant. More alts were also noted in post anti-EGFR therapy LB vs. KRAS wt anti-EGFR-naïve LB (n = 6) (9.5 vs. 5) among patients with KRAS wild-type tumors, although the difference was not significant (p = 0.182).Conclusions: LB across mCRC therapy detects driver mutations, monitors disease burden, and identifies sub-clonal alts that reflect drug resistance, tumor evolution, and heterogeneity. Interpretation of LB results is impacted by clinical context

    Transcriptional regulation of the cinnamyl alcohol dehydrogenase gene from sweetpotato in response to plant developmental stage and environmental stress

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    Cinnamyl alcohol dehydrogenase (CAD) is a key enzyme in the biosynthesis of lignin. We have isolated full length of a cDNA encoding CAD (IbCAD1) that was previously identified as the most abundant gene in an EST library of sweetpotato suspension cells. Phylogenetic analysis revealed that IbCAD1 belongs to the family of defense-related CADs. High levels of IbCAD1 mRNA were found in the roots of sweetpotato, but not in the leaves and petioles. The IbCAD1 gene transcripts were highly induced by cold, wounding, and reactive oxygen species. Analyses of transcriptional regulation of the IbCAD1 gene in transgenic tobacco plants carrying the IbCAD1 promoter–GUS revealed that IbCAD1 promoter expression was strong in the roots, but barely detectable in the cotyledons. IbCAD1 promoter activity increased with increasing root age, and strong promoter expression was observed in the lateral root emergence sites and in root tips. Weak GUS expression was observed in lignified tissues of vascular system of mature leaves and stems. IbCAD1 promoter activity was strongly induced in response to the biotic and abiotic stresses, with the strongest inducer being wounding, and was also induced by salicylic acid (SA) and jasmonic acid (JA) as well as by abscisic acid (ABA) and 6-benzylaminopurine. Taken together, our data suggest that IbCAD1 can be involved in JA- and SA-mediated wounding response and ABA-mediated cold response, respectively. The IbCAD1 gene may play a role in the resistance mechanism to biotic and abiotic stresses as well as in tissue-specific developmental lignification
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