1,692 research outputs found
The factor VII activating protease G511E (Marburg) variant and cardiovascular risk
A previous study had shown a strong relationship between a variant in factor VII activating protease (FSAP G511E) and advanced carotid atheroma. In-vitro, the variant has reduced fibrinolytic but normal pro-coagulant activity, which may constitute a prothrombotic state. The current study has addressed risk for coronary heart disease in a prospective study of cardio vascular disorders (Northwick Park Heart Study II). An interactive effect upon risk was found between the 511E allele and elevated levels of cholesterol and triglyceride. Fibrinogen could substitute for triglyceride levels in this risk-interaction analysis. The findings support the proposal that the FSAP 511E allele exacerbates atherosclerosis or its clinical sequelae
Elastic constants of 3-, 4- and 6-connected chiral and anti-chiral honeycombs subject to uniaxial in-plane loading
Finite Element models are developed for the in-plane linear elastic constants of a family of honeycombs comprising arrays of cylinders connected by ligaments. Honeycombs having cylinders with 3, 4 and 6 ligaments attached to them are considered, with two possible configurations explored for each of the 3- (trichiral and anti-trichiral) and 4- (tetrachiral and anti-tetrachiral) connected systems. Honeycombs for each configuration have been manufactured using rapid prototyping and subsequently characterised for mechanical properties through in-plane uniaxial loading to verify the models. An interesting consequence of the family of 'chiral' honeycombs presented here is the ability to produce negative Poisson's ratio (auxetic) response. The deformation mechanisms responsible for auxetic functionality in such honeycombs are discussed
Shot noise of spin polarized electrons
The shot noise of spin polarized electrons is shown to be generically
dependent upon spin-flip processes. Such a situation represents perhaps the
simplest instance where the two-particle character of current fluctuations out
of equilibrium is explicit, leading to trinomial statistics of charge transfer
in a single channel model. We calculate the effect of spin-orbit coupling,
magnetic impurities, and precession in an external magnetic field on the noise
in the experimentally relevant cases of diffusive wires and lateral
semiconductor dots, finding dramatic enhancements of the Fano factor. The
possibility of using the shot noise to measure the spin-relaxation time in an
open mesoscopic system is raised.Comment: Published version. Minor clarifications and correction
Asymptotic Expansions for Stationary Distributions of Perturbed Semi-Markov Processes
New algorithms for computing of asymptotic expansions for stationary
distributions of nonlinearly perturbed semi-Markov processes are presented. The
algorithms are based on special techniques of sequential phase space reduction,
which can be applied to processes with asymptotically coupled and uncoupled
finite phase spaces.Comment: 83 page
Selenium poisoning in livestock: a review and progress
Selenium in certain soils may be taken up by plants in amounts to render them
toxic. Seleniferous forage can be found in most of the western states. Intoxication
of livestock by seleniferous plants has been classified as acute and chronic. Acute
poisoning results from consumption of plants having high levels of Se; chronic Se
poisoning has been described in two forms— alkali disease and blind staggers. Alkali
disease is said to result from the consumption of seleniferous grains and grasses,
and is manifest by loss of hair, lameness, and loss of weight. Blind staggers is slid
to result from the consumption of Se indicator plants and is manifest by wandering,
circling, loss of ability to swallow, and blindness. Some research casts doubt on the
above classification of Se poisoning. Research using pigs (Sus scrofa domesticus) indicates
that the source of Se does not alter the type of lesion or signs of poisoning
observed. There are data available that suggest that blind staggers is not related to
Se poisoning
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Surficial geology and performance assessment for a Radioactive Waste Management Facility at the Nevada Test Site
At the Nevada Test Site, one potentially disruptive scenario being evaluated for the Greater Confinement Disposal (GCD) Facility Performance Assessment is deep post-closure erosion that would expose buried radioactive waste to the accessible environment. The GCD Facility located at the Area 5 Radioactive Waste Management Site (RWMS) lies at the juncture of three alluvial fan systems. Geomorphic surface mapping in northern Frenchman Flat indicates that reaches of these fans where the RWMS is now located have been constructional since at least the middle Quaternary. Mapping indicates a regular sequence of prograding fans with entrenchment of the older fan surfaces near the mountain fronts and construction of progressively younger inset fans farther from the mountain fronts. At the facility, the oldest fan surfaces are of late Pleistocene and Holocene age. More recent geomorphic activity has been limited to erosion and deposition along small channels. Trench and pit wall mapping found maximum incision in the vicinity of the RWMS to be less than 1.5 m. Based on collected data, natural geomorphic processes are unlikely to result in erosion to a depth of more than approximately 2 m at the facility within the 10,000-year regulatory period
The opioid and related drug epidemics in rural Appalachia: A systematic review of populations affected, risk factors, and infectious diseases
Background/aims: To examine trends in rural Appalachian opioid and related drug epidemics during the past 10 years, including at-risk populations, substance use shifts and correlates, and associated infections. Methods: We conducted this review in accordance with the Preferred Reporting Items for Systematic Reviews (PRISMA) guidelines. Seven databases were searched for quantitative studies, published between January 2006 and December 2017, of drug use, drug-related mortality, or associated infections in rural Appalachia. Results: Drug-related deaths increased in study states, and a high incidence of polydrug toxicity was noted. Rural substance use was most common among young, white males, with low education levels. A history of depression/anxiety was common among study populations. Prescription opioids were most commonly used, often in conjunction with sedatives. Women emerged as a distinct user subpopulation, with different routes of drug use initiation and drug sources. Injection drug use was accompanied by risky injection behaviors and was associated with hepatitis C. Conclusions: This review can help to inform substance use intervention development and implementation in rural Appalachian populations. Those at highest risk are young, white males who often engage in polysubstance use and have a history of mental health issues. Differences in risk factors among other groups and characteristics of drug use in rural Appalachian populations that are conducive to human immunodeficiency virus (HIV) spread also warrant consideration
Modelling negative linear compressibility in tetragonal beam structures
Copyright © 2012 Elsevier. NOTICE: this is the author’s version of a work that was accepted for publication in Mechanics of Materials. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Mechanics of Materials, Volume 46 (2012), DOI: 10.1016/j.mechmat.2011.12.007Most materials compress axially in all directions when loaded hydrostatically. Contrary to this, some materials have been discovered that exhibit negative linear compressibility and, as such, expand along a specific axis or plane. This paper analyses a fundamental mechanism by using a combination of finite element simulations and analytical derivations to show that negative linear compressibility can be found in a body-centred or face-centred tetragonal network of nodes connected by a network of beams. The magnitude and direction of this behaviour depends on the cross geometry in the network
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