39 research outputs found
Unusual behaviours and Impurity Effects in the Noncentrosymmetric Superconductor CePt3Si
We report a study in which the effect of defects/impurities, growth process,
off-stoichiometry, and presence of impurity phases on the superconducting
properties of noncentrosymmetric CePt3Si is analysed by means of the
temperature dependence of the magnetic penetration depth. We found that the
linear low-temperature response of the penetration depth -indicative of line
nodes in this material- is robust regarding sample quality, in contrast to what
is observed in unconventional centrosymmetric superconductors with line nodes.
We discuss evidence that the broadness of the superconducting transition may be
intrinsic, though not implying the existence of a second superconducting
transition. The superconducting transition temperature systematically occurs
around 0.75 K in our measurements, in agreement with resistivity and ac
magnetic susceptibility data but in conflict with specific heat, thermal
conductivity and NMR data in which Tc is about 0.5 K. Random defects do not
change the linear low-temperature dependence of the penetration depth in the
heavy-fermion CePt3Si with line nodes, as they do in unconventional
centrosymmetric superconductors with line nodes.Comment: To appear in New Journal of Physic
Correlation between maternal and neonatal blood Vitamin D level; A cross sectional study of 416 participants visiting a tertiary care hospital in Pakistan
In Pakistan there is limited evidence for the levels and relationship of 25 (OH) Vitamin D [25(OH)D] status in pregnant women and their newborns while the association between maternal 25(OH)D and newborn anthropometric measurements remains unexplored. Sociodemographic data was collected from 213 pregnant mothers during their visit to a tertiary care hospital at the time of childbirth. Anthropometric measurements were performed on all mothers and their newborns and blood samples collected from both for 25(OH)D levels. Participants were classified into two groups according to their 25(OH)D status: Sufficient (25(OH)D â„50nmol/l) and Deficient (25(OH)D 0.05). Our study shows a high prevalence of 25(OH)D deficiency in pregnant women and their newborns and a strong positive association between maternal and newborn 25(OH)D levels. Findings of this study indicate the importance of maintaining sufficient 25(OH)D levels during pregnancy
Genome sequence of the bioplastic-producing ââKnallgasââ bacterium Ralstonia eutropha H16
The H2-oxidizing lithoautotrophic bacterium Ralstonia eutropha H16 is a metabolically versatile organism capable of subsisting, in the absence of organic growth substrates, on H2 and CO2 as its sole sources of energy and carbon. R. eutropha H16 first attracted biotechnological interest nearly 50 years ago with the realization that the organismâs ability to produce and store large amounts of poly[R-(â)-3-hydroxybutyrate] and other polyesters could be harnessed to make biodegradable plastics. Here we report the complete genome sequence of the two chromosomes of R. eutropha H16. Together, chromosome 1 (4,052,032 base pairs (bp)) and chromosome 2 (2,912,490 bp) encode 6,116 putative genes. Analysis of the genome sequence offers the genetic basis for exploiting the biotechnological potential of this organism and provides insights into its remarkable metabolic versatility
Toolbox for visco-elastic material modeling of smart lightweight structures
More and more functionalities will soon be integrated into lightweight structures made of fiber reinforced polymers (FRP). This combines very different materials in minimum space. Consequently, thermo-mechanical risks are of vital concern. The complex stress situation requires a systematic and scalable toolbox of methodologies capable of keeping pace with the growing number and diversity in possible failure risks and sites. The paper reports the status of ongoing work on three expansions to an accelerated test methodology that allows determining the lifetime of FRP structures based on three types of tests: visco-elastic dynamic mechanical analysis, constant strain rate and fatigue tests. The expansions attempt to cover in addition i) various levels of moisture content within the polymer, ii) several laminate stack configurations, and iii) different loading situations including the mix of tension, bending, and shear