667 research outputs found

    Enhanced Thermoelectric Power and Electronic Correlations in RuSe2_2

    Full text link
    We report the electronic structure, electric and thermal transport properties of Ru1x_{1-x}Irx_{x}Se2_2 (x0.2x \leq 0.2). RuSe2_2 is a semiconductor that crystallizes in a cubic pyrite unit cell. The Seebeck coefficient of RuSe2_2 exceeds -200 μ\muV/K around 730 K. Ir substitution results in the suppression of the resistivity and the Seebeck coefficient, suggesting the removal of the peaks in density of states near the Fermi level. Ru0.8_{0.8}Ir0.2_{0.2}Se2_{2} shows a semiconductor-metal crossover at about 30 K. The magnetic field restores the semiconducting behavior. Our results indicate the importance of the electronic correlations in enhanced thermoelectricity of RuSb2_{2}.Comment: 6 pages, 4 figure

    Interplay between pulsations and mass loss in the blue supergiant 55 Cygnus = HD 198478

    Get PDF
    Blue supergiant stars are known to display photometric and spectroscopic variability that is suggested to be linked to stellar pulsations. Pulsational activity in massive stars strongly depends on the star's evolutionary stage and is assumed to be connected with mass-loss episodes, the appearance of macroturbulent line broadening, and the formation of clumps in the wind. To investigate a possible interplay between pulsations and mass-loss, we carried out an observational campaign of the supergiant 55 Cyg over a period of five years to search for photospheric activity and cyclic mass-loss variability in the stellar wind. We modeled the H, He I, Si II and Si III lines using the nonlocal thermal equilibrium atmosphere code FASTWIND and derived the photospheric and wind parameters. In addition, we searched for variability in the intensity and radial velocity of photospheric lines and performed a moment analysis of the line profiles to derive frequencies and amplitudes of the variations. The Halpha line varies with time in both intensity and shape, displaying various types of profiles: P Cygni, pure emission, almost complete absence, and double or multiple peaked. The star undergoes episodes of variable mass-loss rates that change by a factor of 1.7-2 on different timescales. We also observe changes in the ionization rate of Si II and determine a multiperiodic oscillation in the He I absorption lines, with periods ranging from a few hours to 22.5 days. We interpret the photospheric line variations in terms of oscillations in p-, g-, and strange modes. We suggest that these pulsations can lead to phases of enhanced mass loss. Furthermore, they can mislead the determination of the stellar rotation. We classify the star as a post-red supergiant, belonging to the group of alpha Cyg variables.Comment: 20 pages, 18 figures, 3 tables, accepted to Astronomy & Astrophysic

    Magnetic Determination of Hc2H_{c2} under Accurate Alignment in (TMTSF)2_2ClO4_4

    Full text link
    Cantilever magnetometry has been used to measure the upper critical magnetic field Hc2H_{c2} of the quasi-one dimensional molecular organic superconductor (TMTSF)2_2ClO4_4. From simultaneous resistivity and torque magnetization experiments conducted under precise field alignment, Hc2H_{c2} at low temperature is shown to reach 5T, nearly twice the Pauli paramagnetic limit imposed on spin singlet superconductors. These results constitute the first thermodynamic evidence for a large Hc2H_{c2} in this system and provide support for spin triplet pairing in this unconventional superconductorComment: Submitted July 1, 2003, Accepted December 9, 2003, Physical Review Letter

    Learning ability correlates with brain atrophy and disability progression in RRMS

    Get PDF
    Objective To assess the prognostic value of practice effect on Paced Auditory Serial Addition Test (PASAT) in multiple sclerosis. Methods We compared screening (day a '14) and baseline (day 0) PASAT scores of 1009 patients from the FTY720 Research Evaluating Effects of Daily Oral therapy in Multiple Sclerosis (FREEDOMS) trial. We grouped patients into high and low learners if their PASAT score change was above or below the median change in their screening PASAT quartile group. We used Wilcoxon test to compare baseline disease characteristics between high and low learners, and multiple regression models to assess the respective impact of learning ability, baseline normalised brain volume and treatment on brain volume loss and 6-month confirmed disability progression over 2 years. Results The mean PASAT score at screening was 45.38, increasing on average by 3.18 from day a '14 to day 0. High learners were younger (p=0.003), had lower Expanded Disability Status Scale score (p=0.031), higher brain volume (p<0.001) and lower T2 lesion volume (p=0.009) at baseline. Learning status was not significantly associated with disability progression (HR=0.953, p=0.779), when adjusting for baseline normalised brain volume, screening PASAT score and treatment arm. However, the effect of fingolimod on disability progression was more pronounced in high learners (HR=0.396, p<0.001) than in low learners (HR=0.798, p=0.351; p for interaction=0.05). Brain volume loss at month 24 tended to be higher in low learners (0.17%, p=0.058), after adjusting for the same covariates. Conclusions Short-term practice effects on PASAT are related to brain volume, disease severity and age and have clinically meaningful prognostic implications. High learners benefited more from fingolimod treatment

    Primary cultured fibroblasts derived from patients with chronic wounds: a methodology to produce human cell lines and test putative growth factor therapy such as GMCSF

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>Multiple physiologic impairments are responsible for chronic wounds. A cell line grown which retains its phenotype from patient wounds would provide means of testing new therapies. Clinical information on patients from whom cells were grown can provide insights into mechanisms of specific disease such as diabetes or biological processes such as aging.</p> <p>The objective of this study was 1) To culture human cells derived from patients with chronic wounds and to test the effects of putative therapies, Granulocyte-Macrophage Colony Stimulating Factor (GM-CSF) on these cells. 2) To describe a methodology to create fibroblast cell lines from patients with chronic wounds.</p> <p>Methods</p> <p>Patient biopsies were obtained from 3 distinct locations on venous ulcers. Fibroblasts derived from different wound locations were tested for their migration capacities without stimulators and in response to GM-CSF. Another portion of the patient biopsy was used to develop primary fibroblast cultures after rigorous passage and antimicrobial testing.</p> <p>Results</p> <p>Fibroblasts from the non-healing edge had almost no migration capacity, wound base fibroblasts were intermediate, and fibroblasts derived from the healing edge had a capacity to migrate similar to healthy, normal, primary dermal fibroblasts. Non-healing edge fibroblasts did not respond to GM-CSF. Six fibroblast cell lines are currently available at the National Institute on Aging (NIA) Cell Repository.</p> <p>Conclusion</p> <p>We conclude that primary cells from chronic ulcers can be established in culture and that they maintain their <it>in vivo </it>phenotype. These cells can be utilized for evaluating the effects of wound healing stimulators <it>in vitro</it>.</p

    Statin utilization and lipid goal attainment in high or very-high cardiovascular risk patients: Insights from Italian general practice

    Get PDF
    Background and aims: Statin utilization and lipid goal achievement were estimated in a large sample of Italian patients at high/very-high cardiovascular (CV) risk. Methods: Patients aged â¥18 years with a valid low-density lipoprotein cholesterol (LDL-C) measurement in 2015 were selected from the IMS Health Real World Data database; non-high-density lipoprotein cholesterol (non-HDL-C) was assessed in those with available total cholesterol measurements. Index dates were defined as the last valid lipid measurement in 2015. Patients were hierarchically classified into mutually exclusive risk categories: heterozygous familial hypercholesterolemia (primary and secondary prevention), atherosclerotic CV disease (including recent acute coronary syndrome [ACS], chronic coronary heart disease, stroke, and peripheral arterial disease), and diabetes mellitus (DM) alone. Statin and non-statin lipid-modifying therapy (LMT) use, and European Society of Cardiology (ESC)/European Atherosclerosis Society (EAS) guideline-recommended goal attainment, were assessed. Results: Among 66,158 patients meeting selection criteria, the overall rate of LMT prescriptions was 53.3%, including 7.7% on high-intensity statin therapy. Statin use was highest for recent ACS and lowest for DM alone. LDL-C goal attainment was 16.0% for <1.8 mmol/l and 45.0% for <2.5 mmol/l; 24.3% reached non-HDL-C <2.6 mmol/l and 52.2% were at <3.3 mmol/l. Goal achievement was greatest with high-intensity statin use. Conclusions: Statin use in this cohort was consistent with previous reports in Italian patients at high/very-high CV risk, and low relative to statin use in other European countries. The low rate of ESC/EAS lipid goal attainment observed was consistent with outcomes of other European studies

    Antibody response to SARS-CoV-2 vaccines in patients with relapsing multiple sclerosis treated with evobrutinib: A Bruton\u27s tyrosine kinase inhibitor

    Get PDF
    BACKGROUND: Evobrutinib is an oral, central nervous system (CNS)-penetrant and highly selective covalent Bruton\u27s tyrosine kinase inhibitor under clinical development for patients with relapsing multiple sclerosis (RMS). OBJECTIVE: To investigate the effect of evobrutinib on immune responses in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccinated patients with RMS from a Phase II trial (NCT02975349). METHODS: A RESULTS: In the vaccinated subgroup, mean/minimum evobrutinib exposure pre-vaccination was 105.2/88.7 weeks. In total, 43 of 45 patients developed/increased S1/S2 IgG antibody levels post-vaccination; one patient\u27s antibody response remained negative post-vaccination and the other had antibody levels above the upper limit of detection, both pre- and post-vaccination. Most patients ( CONCLUSION: These results suggest evobrutinib, an investigational drug with therapeutic potential for patients with RMS, acts as an immunomodulator, that is, it inhibits aberrant immune cell responses in patients with RMS, while responsiveness to foreig

    Determination of the target nucleosides for members of two families of 16S rRNA methyltransferases that confer resistance to partially overlapping groups of aminoglycoside antibiotics

    Get PDF
    The 16S ribosomal RNA methyltransferase enzymes that modify nucleosides in the drug binding site to provide self-resistance in aminoglycoside-producing micro-organisms have been proposed to comprise two distinct groups of S-adenosyl-l-methionine (SAM)-dependent RNA enzymes, namely the Kgm and Kam families. Here, the nucleoside methylation sites for three Kgm family methyltransferases, Sgm from Micromonospora zionensis, GrmA from Micromonospora echinospora and Krm from Frankia sp. Ccl3, were experimentally determined as G1405 by MALDI-ToF mass spectrometry. These results significantly extend the list of securely characterized G1405 modifying enzymes and experimentally validate their grouping into a single enzyme family. Heterologous expression of the KamB methyltransferase from Streptoalloteichus tenebrarius experimentally confirmed the requirement for an additional 60 amino acids on the deduced KamB N-terminus to produce an active methyltransferase acting at A1408, as previously suggested by an in silico analysis. Finally, the modifications at G1405 and A1408, were shown to confer partially overlapping but distinct resistance profiles in Escherichia coli. Collectively, these data provide a more secure and systematic basis for classification of new aminoglycoside resistance methyltransferases from producers and pathogenic bacteria on the basis of their sequences and resistance profiles

    The ACROSS study : Long-term efficacy of fingolimod in patients with relapsing-remitting multiple sclerosis

    Get PDF
    In chronic diseases such as multiple sclerosis requiring lifelong treatment, studies on long-term outcomes are important. To assess disability and magnetic resonance imaging-related outcomes in relapsing multiple sclerosis patients from a Phase 2 study of fingolimod 10 or more years after randomization and to compare outcomes in patients who had a higher fingolimod exposure versus those with a lower fingolimod exposure. ACROSS was a cross-sectional follow-up study of patients originally enrolled in a Phase 2 fingolimod proof-of-concept study (NCT00333138). Disability and magnetic resonance imaging-related outcomes were assessed in patients grouped according to fingolimod treatment duration, based on an arbitrary cut-off: ≥8 years (high exposure) and <8 years (low exposure). Overall, 175/281 (62%) patients participated in ACROSS; 104 (59%) of these were classified "high exposure." At 10 years, patients in the high-exposure group had smaller increases in Expanded Disability Status Scale (+0.55 vs. +1.21), and lower frequencies of disability progression (34.7% vs. 56.1%), wheelchair use (4.8% vs. 16.9%), or transition to secondary progressive multiple sclerosis (9.6% vs. 22.5%) than those in the low-exposure group. The high-exposure patients also had less progression in most magnetic resonance imaging-related outcomes. After 10 years of fingolimod treatment, disability progression was lower in the high-exposure group than in the low-exposure group
    corecore