934 research outputs found

    Ultrahigh field MRI in clinical neuroimmunology: a potential contribution to improved diagnostics and personalised disease management

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    Conventional magnetic resonance imaging (MRI) at 1.5 Tesla (T) is limited by modest spatial resolution and signal-to-noise ratio (SNR), impeding the identification and classification of inflammatory central nervous system changes in current clinical practice. Gaining from enhanced susceptibility effects and improved SNR, ultrahigh field MRI at 7 T depicts inflammatory brain lesions in great detail. This review summarises recent reports on 7 T MRI in neuroinflammatory diseases and addresses the question as to whether ultrahigh field MRI may eventually improve clinical decision-making and personalised disease management

    High prevalence of vitamin D insufficiency in professional handball athletes

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    OBJECTIVES: Vitamin D affects multiple body functions through the regulation of gene expression. In sports medicine, its influence on musculoskeletal health and performance is of particular interest. Vitamin D insufficiency might decrease athletic performance and increase the risk of musculoskeletal injuries. Several studies have demonstrated vitamin D deficiency in professional athletes; however, the prevalence of vitamin D insufficiency in professional handball players is yet unknown. METHODS: The study was planned as a prospective, non-interventional study. We examined 70 male elite handball athletes (first league) in a pre-competition medical assessment in July. Age, height, weight, body mass index, 25-OH vitamin D, calcium, and parathyroid hormone were evaluated, and a sun exposure score was calculated. Players were then divided into two groups of vitamin D levels: insufficient (<30 ng/mL) and sufficient (≥30 ng/mL). RESULTS: The mean 25-OH vitamin D level of the 70 players was 33.5 ± 10.9 ng/mL (median 32.2, IQR 26.5-38.9 ng/mL). Thirty-nine (55.7%) had sufficient and 31 (44.3%) insufficient levels. Athletes with sufficient vitamin D levels had significantly lower parathyroid hormone levels than athletes with insufficiency (24.9 ± 12.1 vs. 33.5 ± 15.1 ng/mL, p = 0.02). All other parameters evaluated demonstrated no significant difference between the two groups. CONCLUSION: Vitamin D insufficiency is a common finding in professional handball athletes even in summer, which might negatively affect physical performance. Furthermore, it might lead to an increased risk of musculoskeletal injuries and infections. This should be evaluated in further studies

    Sesquiterpenes from the essential oil of Laurencia dendroidea (Ceramiales, Rhodophyta): isolation, biological activities and distribution among seaweeds

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    Two known sesquiterpenes (1R*,2S*,3R*,5S*,8S*,9R*)-2,3,5,9-tetramethyltricyclo[6.3.0.0(1,5)]undecan-2-ol and (1S*,2S*,3S*,5S*,8S*,9S*)-2,3,5,9-tetramethyltricyclo-[6.3.0.0(1,5)]undecan-2-ol were isolated for the first time from the essential oil of the red seaweed Laurencia dendroidea collected in the Brazilian coast. These compounds were not active against eight bacteria strains and the yeast Candida albicans, but showed some antioxidant activity. Both compounds were also found in other seaweed species showing that they are not exclusive taxonomic markers to the genus Laurencia.Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Ministério da SaúdeMinistério de Ciência e TecnologiaCNPq - INCT-Redoxom

    Monitoring of tritium purity during long-term circulation in the KATRIN test experiment LOOPINO using laser Raman spectroscopy

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    The gas circulation loop LOOPINO has been set up and commissioned at Tritium Laboratory Karlsruhe (TLK) to perform Raman measurements of circulating tritium mixtures under conditions similar to the inner loop system of the neutrino-mass experiment KATRIN, which is currently under construction. A custom-made interface is used to connect the tritium containing measurement cell, located inside a glove box, with the Raman setup standing on the outside. A tritium sample (purity > 95%, 20 kPa total pressure) was circulated in LOOPINO for more than three weeks with a total throughput of 770 g of tritium. Compositional changes in the sample and the formation of tritiated and deuterated methanes CT_(4-n)X_n (X=H,D; n=0,1) were observed. Both effects are caused by hydrogen isotope exchange reactions and gas-wall interactions, due to tritium {\beta} decay. A precision of 0.1% was achieved for the monitoring of the T_2 Q_1-branch, which fulfills the requirements for the KATRIN experiment and demonstrates the feasibility of high-precision Raman measurements with tritium inside a glove box

    Interface driven magnetoelectric effects in granular CrO2

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    Antiferromagnetic and magnetoelectric Cr2O3-surfaces strongly affect the electronic properties in half metallic CrO2. We show the presence of a Cr2O3 surface layer on CrO3 grains by high-resolution transmission electron microscopy. The effect of these surface layers is demonstrated by measurements of the temperature variation of the magnetoelectric susceptibility. A major observation is a sign change at about 100 K followed by a monotonic rise as a function of temperature. These electric field induced moments in CrO3 are correlated with the magnetoelectric susceptibility of pure Cr2O3. This study indicates that it is important to take into account the magnetoelectric character of thin surface layers of Cr2O3 in granular CrO2 for better understanding the transport mechanism in this system. The observation of a finite magnetoelectric susceptibility near room temperature may find utility in device applications.Comment: Figure 1 with strongly reduced resolutio

    Ionization dynamics in intense pulsed laser radiation. Effects of frequency chirping

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    Via a non-perturbative method we study the population dynamics and photoelectron spectra of Cs atoms subject to intense chirped laser pulses, with gaussian beams. We include above threshold ionization spectral peaks. The frequency of the laser is near resonance with the 6s-7p transition. Dominant couplings are included exactly, weaker ones accounted for perturbatively. We calculate the relevant transition matrix elements, including spin-orbit coupling. The pulse is taken to be a hyperbolic secant in time and the chirping a hyperbolic tangent. This choice allows the equations of motions for the probability amplitudes to be solved analytically as a series expansion in the variable u=(tanh(pi t/tau)+1)/2, where tau is a measure of the pulse length. We find that the chirping changes the ionization dynamics and the photoelectron spectra noticeably, especially for longer pulses of the order of 10^4 a.u. The peaks shift and change in height, and interference effects between the 7p levels are enhanced or diminished according to the amount of chirping and its sign. The integrated ionization probability is not strongly affected.Comment: Accepted by J. Phys. B; 18 pages, 17 figures. Latex, uses ioplppt.sty, iopl10.sty and psfig.st
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