2,032 research outputs found
Investigation of three classes of composite materials for space vehicle application
Three classes of composite materials for space vehicle applicatio
A Myelin Proteolipid Protein-LacZ Fusion Protein Is Developmentally Regulated and Targeted to the Myelin Membrane in Transgenic Mice
Transgenic mice were generated with a fusion gene carrying a portion of the murine myelin proteolipid protein (PLP) gene, including the first intron, fused to the E. coli LacZ gene. Three transgenic lines were derived and all lines expressed the transgene in central nervous system white matter as measured by a histochemical assay for the detection of β-galactosidase activity. PLP-LacZ transgene expression was regulated in both a spatial and temporal manner, consistent with endogenous PLP expression. Moreover, the transgene was expressed specifically in oligodendrocytes from primary mixed glial cultures prepared from transgenic mouse brains and appeared to be developmentally regulated in vitro as well. Transgene expression occurred in embryos, presumably in pre- or nonmyelinating cells, rather extensively throughout the peripheral nervous system and within very discrete regions of the central nervous system. Surprisingly, beta-galactosidase activity was localized predominantly in the myelin in these transgenic animals, suggesting that the NH_2-terminal 13 amino acids of PLP, which were present in the PLP-LacZ gene product, were sufficient to target the protein to the myelin membrane. Thus, the first half of the PLP gene contains sequences sufficient to direct both spatial and temporal gene regulation and to encode amino acids important in targeting the protein to the myelin membrane
A study of low density, high strength, and high modulus whisker filament and laminar composites third quarterly progress report, 5 feb. - 5 may 1966
Isotopic provenancing of Pb in Mitrovica, northern Kosovo: source identification of chronic Pb enrichment in soils, house dust and scalp hair
Mitrovica, northern Kosovo, is the site of some of the highest Pb concentrations reported in human populations; exemplified by Pb concentrations in scalp hair of up to 130 μg g-1 and widely-publicized of Pb-related ill-health and mortality amongst internally displaced populations. High human Pb burdens are accompanied by elevated concentrations of potentially harmful elements (PHEs) in soils and house dust within the city, which has a long history of mining and metallurgy. In this study enrichment-levels for PHEs in soils are quantified and compared to environmental quality guidelines and a statistically-derived estimation of background concentration. In addition, Pb isotopes (207Pb/206Pb, 208Pb/206Pb) are used to characterise the isotopic signatures of potential point sources of Pb and a mixing model employed to quantify the contribution of sources to Pb present in soils, house dust, and the scalp hair of children and young people. Pb isotopic evidence suggests that Pb in surface soils and house-dust is predominantly sourced from historical deposition of Pb-containing aerosols from metal smelting, with lower contributions from wind-blown dispersal of metalliferous waste. Pb present in scalp hair is interpreted as the result of non-occupational exposure and the ingestion and/or inhalation of Pb-enriched surface soil and house dust. This study represents one of the very few instances where this type of geochemical tracing technique has been successfully applied to definitively identify the source of Pb present within biological samples. The results of this study are of particular relevance to environmental management and highlight the human health risk posed by the legacy of now inactive mining and metallurgy in addition to the challenge posed in mitigating the risk posed by diffuse soil pollution. © 2015 Elsevier Ltd
Recent changes in riparian and floodplain vegetation in England and Wales and its geomorphic implications
The use of geomorphological mapping and modelling for identifying land affected by metal contamination on river floodplains
Accountability in the NHS: the impact on cancer care.
Accountability of service delivery is becoming increasingly complex and never has this been more apparent than in the field of Oncology. Cancer care has an unrivalled level of complexity not only in the heterogeneity of management of the disease itself but increasingly in the myriad of service providers, specialities, policymakers and regulatory bodies overseeing its delivery. The stepwise series of changes to NHS structures over recent decades has had an enormous impact on our ability to answer key questions which lie at the heart of accountability: who is making the key decisions about changes to cancer care delivery? What are these reforms achieving? How can they be influenced? It is only through clear and transparent decision-making that we may have any hope of implementing, monitoring and influencing the effects of evidence-based change. However, with growing complexity of service structures and an increasing number of bodies developing ambitious and complex strategies, in a context of resource restraint and system pressures, it has become very difficult to answer these questions clearly. This increasing lack of clarity and transparency around such fundamental questions may mean that, despite there being such a pressing need and apparent desire for accountability in cancer care, paradoxically we may actually be deviating further and further away from this. Perhaps it is time for less complexity and for the decision-makers to get back to some fundamental principles which clinicians have embraced in evidence-based medicine: what is being done and by whom? Is this change beneficial and if not how can we influence change
Assessment of Metal Mining-Contaminated River Sediments in England and Wales
This report reviews how sediments and floodplain soils have been contaminated by abandoned metal mines and recommends what the Environment Agency should do about this issue
The s Process: Nuclear Physics, Stellar Models, Observations
Nucleosynthesis in the s process takes place in the He burning layers of low
mass AGB stars and during the He and C burning phases of massive stars. The s
process contributes about half of the element abundances between Cu and Bi in
solar system material. Depending on stellar mass and metallicity the resulting
s-abundance patterns exhibit characteristic features, which provide
comprehensive information for our understanding of the stellar life cycle and
for the chemical evolution of galaxies. The rapidly growing body of detailed
abundance observations, in particular for AGB and post-AGB stars, for objects
in binary systems, and for the very faint metal-poor population represents
exciting challenges and constraints for stellar model calculations. Based on
updated and improved nuclear physics data for the s-process reaction network,
current models are aiming at ab initio solution for the stellar physics related
to convection and mixing processes. Progress in the intimately related areas of
observations, nuclear and atomic physics, and stellar modeling is reviewed and
the corresponding interplay is illustrated by the general abundance patterns of
the elements beyond iron and by the effect of sensitive branching points along
the s-process path. The strong variations of the s-process efficiency with
metallicity bear also interesting consequences for Galactic chemical evolution.Comment: 53 pages, 20 figures, 3 tables; Reviews of Modern Physics, accepte
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