50 research outputs found

    Pressure induced softening of YB_6: pressure effect on the Ginzburg-Landau parameter \kappa=\lambda/\xi

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    Measurements of the transition temperature T_c, the second critical filed H_{c2} and the magnetic penetration depth \lambda under hydrostatic pressure (up to 9.2 kbar) in the YB_6 superconductor were carried out. A pronounced and {\it negative} pressure effects (PE) on T_c and H_{c2} with dT_c/dp=-0.0547(4) K/kbar and \mu_0dH_{c2}(0)/dp =-4.84(20) mT/kbar, and zero PE on \lambda(0) were observed. The PE on the coherence length d\xi(0)/dp=0.28(2) nm/kbar was calculated from the measured pressure dependence of H_{c2}(0). Together with the zero PE on the magnetic penetration depth \lambda(0), our results imply that the Ginzburg-Landau parameter \kappa(0)=\xi(0)/\lambda(0) depends on pressure and that pressure "softens" YB_6, e.g. moves it to the type-I direction.Comment: 4 pages, 2 figure

    The barocaloric effect: A Spin-off of the Discovery of High-Temperature Superconductivity

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    Some key results obtained in joint research projects with Alex M\"uller are summarized, concentrating on the invention of the barocaloric effect and its application for cooling as well as on important findings in the field of high-temperature superconductivity resulting from neutron scattering experiments.Comment: 26 pages, 9 figure

    Tricarbonyl M(I) (M = Re, 99mTc) complexes bearing acridine fluorophores : synthesis, characterization, DNA interaction studies and nuclear targeting

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    © The Royal Society of Chemistry 2010New pyrazolyl-diamine ligands with acridine derivatives at the 4-position of the pyrazolyl ring were synthesized and characterized (L1 and L2). Coordination towards the fac-[M(CO)3]+ (M = Re, 99mTc) led to complexes fac-[M(CO)3(κ3-L)] (L = L1: M = Re1, Tc1; L = L2: M = Re2, Tc2). The interaction of the novel pyrazolyl-diamine ligands (L1 and L2) and rhenium(I) complexes (Re1 and Re2) with calf thymus DNA (CT-DNA) was investigated by a variety of techniques, namely UV-visible , fluorescence spectroscopy and circular and linear dichroism . Compounds L1 and Re1 have moderate affinity to CT-DNA and bind to DNA by intercalation, while L2 and Re2 have a poor affinity for CT-DNA. Moreover, LD measurements showed that L1 and Re1 act as perfect intercalators . By confocal fluorescence microscopy we found that L1 and Re1 internalize and localize in the nucleus of B16F1 murine melanoma cells . The congener Tc1 complex also targets the cell nucleus exhibiting a time-dependent cellular uptake and a fast and high nuclear internalization (67.2% of activity after 30 min). Plasmid DNA studies have shown that Tc1 converts supercoiled (sc) puc19 DNA to the open circular (oc) form.Teresa Esteves and Sofia Gama thank the FCT for a doctoral and postdoctoral research grants (SFRH/BD/29154/2006 and SFRH/BPD/29564/2006, respectively). COST Action D39 is also acknowledge. The QITMS instrument was acquired with the support of the Programa Nacional de Reequipamento Científico (Contract>REDE/1503/REM/2005-ITN) of Fundação para a Ciência e a Tecnologia and is part of RNEM - Rede Nacional de Espectrometria de Massa

    The role of immune checkpoint inhibitors in clinical practice: an analysis of the treatment patterns, survival and toxicity rates by sex.

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    PURPOSE Our aim is to describe the role of immune checkpoint inhibitors (ICI) in clinical practice by providing the patient and tumor characteristics as well as survival and toxicity rates by sex. METHODS We used electronic health records to identify patients treated at the Cancer Center of the University Hospital Bern, Switzerland between January 1, 2017 and June 16, 2021. RESULTS We identified 5109 patients, 689 of whom (13.5%) received at least one dose of ICI. The fraction of patients who were prescribed ICI increased from 8.6% in 2017 to 22.9% in 2021. ICI represented 13.2% of the anticancer treatments in 2017 and increased to 28.2% in 2021. The majority of patients were male (68.7%), who were older than the female patients (median age 67 vs. 61 years). Over time, adjuvant and first line treatments increased for both sexes. Lung cancer and melanoma were the most common cancer types in males and females. The incidence of irAEs was higher among females (38.4% vs. 28.1%) and lead more often to treatment discontination in females than in males (21.1% vs. 16.8%). Independent of sex, the occurrence of irAEs was associated with greater median overall survival (OS, not reached vs. 1.1 years). Female patients had a longer median OS than males (1.9 vs. 1.5 years). CONCLUSIONS ICI play an increasingly important role in oncology. irAEs are more frequent in female patients and are associated with a longer OS. More research is needed to understand the association between patient sex and toxicity and survival

    A Comprehensive Workflow for General-Purpose Neural Modeling with Highly Configurable Neuromorphic Hardware Systems

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    In this paper we present a methodological framework that meets novel requirements emerging from upcoming types of accelerated and highly configurable neuromorphic hardware systems. We describe in detail a device with 45 million programmable and dynamic synapses that is currently under development, and we sketch the conceptual challenges that arise from taking this platform into operation. More specifically, we aim at the establishment of this neuromorphic system as a flexible and neuroscientifically valuable modeling tool that can be used by non-hardware-experts. We consider various functional aspects to be crucial for this purpose, and we introduce a consistent workflow with detailed descriptions of all involved modules that implement the suggested steps: The integration of the hardware interface into the simulator-independent model description language PyNN; a fully automated translation between the PyNN domain and appropriate hardware configurations; an executable specification of the future neuromorphic system that can be seamlessly integrated into this biology-to-hardware mapping process as a test bench for all software layers and possible hardware design modifications; an evaluation scheme that deploys models from a dedicated benchmark library, compares the results generated by virtual or prototype hardware devices with reference software simulations and analyzes the differences. The integration of these components into one hardware-software workflow provides an ecosystem for ongoing preparative studies that support the hardware design process and represents the basis for the maturity of the model-to-hardware mapping software. The functionality and flexibility of the latter is proven with a variety of experimental results

    Admixture of an s-wave component to the d-wave gap symmetry in high-temperature superconductors

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    Neutron crystal-field spectroscopy experiments in the Y- and La-type high-temperature superconductors HoBa2Cu3O6.56, HoBa2Cu4O8, and La1.81Sr0.15Ho0.04CuO4 are reviewed. By this bulk-sensitive technique, information on the gap function is obtained from the relaxation behavior of crystal-field transitions associated with the Ho3+ ions which sit as local probes close to the superconducting copper-oxide planes. The relaxation data exhibit a peculiar change from a convex to a concave shape between the superconducting transition temperature Tc and the pseudogap temperature T* which can only be modelled satisfactorily if the gap function of predominantly d-wave symmetry includes an s-wave component of the order of 20-25%, independent of the doping level. Moreover, our results are compatible with an unusual temperature dependence of the gap function in the pseudogap region (Tc<T<T*), i.e., a breakup of the Fermi surface into disconnected arcs.Comment: 14 pages, 3 figures, 1 table; accepted for publication in J. Supercond. Nov. Mag

    Supersymmetric Higgs Yukawa Couplings to Bottom Quarks at next-to-next-to-leading Order

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    The effective bottom Yukawa couplings are analyzed for the minimal supersymmetric extension of the Standard Model at two-loop accuracy within SUSY-QCD. They include the resummation of the dominant corrections for large values of tg(beta). In particular the two-loop SUSY-QCD corrections to the leading SUSY-QCD and top-induced SUSY-electroweak contributions are addressed. The residual theoretical uncertainties range at the per-cent level.Comment: 25 pages, 9 figures, added comments and references, typos corrected, results unchanged, published versio

    Guided assembly of nanoparticles on electrostatically charged nanocrystalline diamond thin films

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    We apply atomic force microscope for local electrostatic charging of oxygen-terminated nanocrystalline diamond (NCD) thin films deposited on silicon, to induce electrostatically driven self-assembly of colloidal alumina nanoparticles into micro-patterns. Considering possible capacitive, sp2 phase and spatial uniformity factors to charging, we employ films with sub-100 nm thickness and about 60% relative sp2 phase content, probe the spatial material uniformity by Raman and electron microscopy, and repeat experiments at various positions. We demonstrate that electrostatic potential contrast on the NCD films varies between 0.1 and 1.2 V and that the contrast of more than ±1 V (as detected by Kelvin force microscopy) is able to induce self-assembly of the nanoparticles via coulombic and polarization forces. This opens prospects for applications of diamond and its unique set of properties in self-assembly of nano-devices and nano-systems
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