Assessing composition gradients in multifilamentary superconductors by means of magnetometry methods

We present two magnetometry-based methods suitable for assessing gradients in the critical temperature and hence the composition of multifilamentary superconductors: AC magnetometry and Scanning Hall Probe Microscopy. The novelty of the former technique lies in the iterative evaluation procedure we developed, whereas the strength of the latter is the direct visualization of the temperature dependent penetration of a magnetic field into the superconductor. Using the example of a PIT Nb3Sn wire, we demonstrate the application of these techniques, and compare the respective results to each other and to EDX measurements of the Sn distribution within the sub-elements of the wire.Comment: 7 pages, 8 figures; broken hyperlinks are due to a problem with arXi

Effects of Neutron Irradiation on Pinning Force Scaling in State-of-the-Art Nb3Sn Wires

We present an extensive irradiation study involving five state-of-the-art Nb3Sn wires which were subjected to sequential neutron irradiation up to a fast neutron fluence of 1.6 * 10^22 m^-2 (E > 0.1 MeV). The volume pinning force of short wire samples was assessed in the temperature range from 4.2 to 15 K in applied fields of up to 7 T by means of SQUID magnetometry in the unirradiated state and after each irradiation step. Pinning force scaling computations revealed that the exponents in the pinning force function differ significantly from those expected for pure grain boundary pinning, and that fast neutron irradiation causes a substantial change in the functional dependence of the volume pinning force. A model is presented, which describes the pinning force function of irradiated wires using a two-component ansatz involving a point-pinning contribution stemming from radiation induced pinning centers. The dependence of this point-pinning contribution on fast neutron fluence appears to be a universal function for all examined wire types.Comment: 8 page

Gene identification for the cblD defect of vitamin B12 metabolism

Background Vitamin B12 (cobalamin) is an essential cofactor in several metabolic pathways. Intracellular conversion of cobalamin to its two coenzymes, adenosylcobalamin in mitochondria and methylcobalamin in the cytoplasm, is necessary for the homeostasis of methylmalonic acid and homocysteine. Nine defects of intracellular cobalamin metabolism have been defined by means of somatic complementation analysis. One of these defects, the cblD defect, can cause isolated methylmalonic aciduria, isolated homocystinuria, or both. Affected persons present with multisystem clinical abnormalities, including developmental, hematologic, neurologic, and metabolic findings. The gene responsible for the cblD defect has not been identified. Methods We studied seven patients with the cblD defect, and skin fibroblasts from each were investigated in cell culture. Microcell-mediated chromosome transfer and refined genetic mapping were used to localize the responsible gene. This gene was transfected into cblD fibroblasts to test for the rescue of adenosylcobalamin and methylcobalamin synthesis. Results The cblD gene was localized to human chromosome 2q23.2, and a candidate gene, designated MMADHC (methylmalonic aciduria, cblD type, and homocystinuria), was identified in this region. Transfection of wild-type MMADHC rescued the cellular phenotype, and the functional importance of mutant alleles was shown by means of transfection with mutant constructs. The predicted MMADHC protein has sequence homology with a bacterial ATP-binding cassette transporter and contains a putative cobalamin binding motif and a putative mitochondrial targeting sequence. Conclusions Mutations in a gene we designated MMADHC are responsible for the cblD defect in vitamin B12 metabolism. Various mutations are associated with each of the three biochemical phenotypes of the disorder

Hair cortisol concentrations in different breeds of cows: Comparison of hair from unshorn and previously shorn areas and from various regions of the body

The goals of this study were to investigate hair cortisol concentration (HCC) in seven different breeds of cows, to establish reference intervals for HCC in Brown Swiss cows and to compare cortisol concentrations of hair collected from four different areas of the body. Three groups of cows were used. Group 1 comprised 70 healthy cows representing four dairy breeds (Brown Swiss, Swiss Fleckvieh, Holstein Friesian, Water Buffalo) and three beef breeds (Raetian Grey, Limousin, Highland). Group 2 consisted of 60 healthy Brown Swiss cows in which two different hair samples were collected from the thoracic region to establish reference intervals; A samples consisted of hair that had grown for one month in a pre-clipped area, and B samples consisted of hair from a previously unshorn area. Group 3 comprised 21 healthy Brown Swiss cows, in which HCCs were measured in A and B samples from four different body regions (neck, shoulder, thorax, rump). Liquid chromatography tandem mass-spectrometry was used for cortisol measurement. In group 1, the highest HCCs were measured in Holstein Friesian cows at 1,75 pg/mg, which was significantly higher than those of the Brown Swiss, the Swiss Fleckvieh and the Water Buffalo cows. Hair cortisol concentration and daily milk yield of the 40 dairy cows were highly correlated (r = 0,57, P < 0,01). In group 2, the HCCs of 77 % of the A samples and 85 % of the B samp-les were below the laboratory's limit of quantification (LOQ) of 0,50 pg/mg and the results were expressed semiquantitatively as

Antibodies to Lipopolysaccharides after Immunization of Humans with the Rough Mutant Escherichia coli J5

To investigate whether immunization with Escherichia coli J5 boiled cells induces antibodies directed at deep core structures, antibodies against JS lipopolysaccharide (LPS), Re LPSt and Iipid A were measured in the serum of 70 volunteers before and 2 weeks after immunization. To improve the sensitivity and the specificity ofELISAt complexes of core LPS with high-density lipoproteins were used instead of free core LPS as antigens. A median three-fold increase in antibodies directed against J5 LPS was observed, but no significant increase in the antibodies against Re LPS or lipid A was found. Since JS antiserum did not react with several smooth LPS or with Re LPS and lipid At cross-reactivity could not be demonstrated. Thus, immunization of volunteers with E. coli J5 produced a modest specific antibody response against J5 LPS. The mechanism of protection previously observed with J5 antiserum remains unclea