Erythropoietin release from baboom renal allografts treated with subcellular kidney cell fractions

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Disorder Induced Effects on the Critical Current Density of Iron Pnictide BaFe_1.8 Co_0.2 As_2 single crystals

Investigating the role of disorder in superconductors is an essential part of characterizing the fundamental superconducting properties as well as assessing potential applications of the material. In most cases, the information available on the defect matrix is poor, making such studies difficult, but the situation can be improved by introducing defects in a controlled way, as provided by neutron irradiation. In this work, we analyze the effects of neutron irradiation on a Ba(Fe$_{1-x}$Co$_x$)$_2$As$_2$ single crystal. We mainly concentrate on the magnetic properties which were determined by magnetometry. Introducing disorder by neutron irradiation leads to significant effects on both the reversible and the irreversible magnetic properties, such as the transition temperature, the upper critical field, the anisotropy, and the critical current density. The results are discussed in detail by comparing them with the properties in the unirradiated state.Comment: accepted for Ph

From Metastable to Coherent Sets – time-discretization schemes

Given a time-dependent stochastic process with trajectories x(t) in a space \Omega, there may be sets such that the corresponding trajectories only very rarely cross the boundaries of these sets. We can analyze such a process in terms of metastability or coherence. Metastable sets M are defined in space M \subset \Omega, coherent sets M(t) \subset \Omega are defined in space and time. Hence, if we extend the space \Omega by the time-variable t, coherent sets are metastable sets in \Omega \times [0,\infty). This relation can be exploited, because there already exist spectral algorithms for the identification of metastable sets. In this article we show that these well-established spectral algorithms (like PCCA+) also identify coherent sets of non-autonomous dynamical systems. For the identification of coherent sets, one has to compute a discretization (a matrix T) of the transfer operator of the process using a space-time-discretization scheme. The article gives an overview about different time-discretization schemes and shows their applicability in two different fields of application

Consequences of the peculiar intrinsic properties of MgB2 on its macroscopic current flow

The influence of two important features of magnesium diboride on the macroscopic transport properties of polycrystalline MgB2 is discussed in the framework of a percolation model. While two band superconductivity does not have significant consequences in the field and temperature range of possible power applications, the opposite is true for the anisotropy of the upper critical field. The field dependence of the critical current densities strongly increases and the macroscopic supercurrents disappear well below the apparent upper critical field. The common scaling laws for the field dependence of the volume pinning force are altered and Kramer's plot is no longer linear, although grain boundary pinning dominates in nearly all polycrystalline MgB2 conductors. In contrast to the conventional superconductors NbTi and Nb3Sn, a significant critical current anisotropy can be induced by the preparation technique of MgB2 tapes

Flux pinning in two-dimensional high temperature superconductors

Various types of high temperature superconducting single crystals (TI-2223, Bi-2212, and Y-123 with oxygen contents between 6.4 and 6.64) were investigated by SQUID magnetometry. Both materials show very {open_quotes}low{close_quotes} lying irreversibility lines (Hllc), which follow an exponential law-and rise rapidly below T/T{sub c}=0.5. High critical current P densities are found only at low temperatures, e.g. J{sub c} is about 2.7{circ}10{sup 10}Am{sup -2} at 1 T and 5 K in TI-2223. A comparison of the condensation energy provided by different types of defects with the thermal energy gives evidence for pinning of individual pancakes by the as-grown defect structure

Correlation of tissue-typing tests in baboon renal allotransplants

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Mixed state properties of superconducting MgB2 single crystals

We report on measurements of the magnetic moment in superconducting MgB2 single crystals. We find \mu_0H_{c2}^c(0) = 3.2 T, \mu_0H_{c2}^{ab}(0) = 14.5 T, \gamma = 4.6, \mu_0H_c(0) = 0.28 T, and \kappa(T_c) = 4.7. The standard Ginzburg-Landau and London model relations lead to a consistent data set and indicate that MgB2 is a clean limit superconductor of intermediate coupling strength with very pronounced anisotropy effects