582 research outputs found

    ASTP simulated lightning test report

    Get PDF
    A simulated lightning test was conducted on the backup spacecraft for the Apollo Soyuz Test Project mission (CSM-119) to determine the susceptibility of the Apollo spacecraft to damage from the indirect effects of lightning. It is demonstrated that induced lightning effects from low-level injected currents can be scaled linearly to those which are obtained in a full threat lightning stroke. Test results indicate that: (1) many of the power and signal critical circuits would fail if subjected to full-threat lightning, (2) pyrotechnic circuits are safe for full-threat lightning, and (3) common-mode voltages exceeded the failure criteria level for all but three of the circuits tested

    Impact of Gene-Gender Effects of Adrenergic Polymorphisms on Hypothalamic-Pituitary-Adrenal Axis Activity in Depressed Patients

    Get PDF
    Objective: There is overwhelming evidence that activation of the hypothalamic-pituitary-adrenal (HPA) system plays a major role in depression and cardiovascular disease in genetically susceptible individuals. We hypothesized that due to the multiple interactions between the sympathetic and the HPA systems via adrenoceptors, polymorphisms in these genes could have an impact on HPA axis activity in major depression. Methods: Using the dexamethasone/corticotrophin-releasing hormone (DEX/CRH) test, we investigated the association of alpha 2-adrenoceptor (ADRA2A -1291C -> G) and the beta 2-adrenoceptor gene (ADRB2 Arg16Gly) in 189 patients with major depression during the acute state of the disease and after remission. Results: Male ADRA2A -1291G allele homozygotes showed significant pretreatment HPA axis hyperactivity, with increased adrenocorticotropin (ACTH; F = 4.9, d.f. = 2, p = 0.009) and cortisol responses (F = 6.4, d.f. = 2, p = 0.003). In contrast, female ADRB2 Arg/Arg homozygotes had increased pretreatment ACTH (F = 7.17, d.f. = 2, p = 0.001) and cortisol (F = 8.95, d.f. = 2, p = 0.000) levels. Interestingly, in the respective genotypes, the stress hormones remained elevated in the second DEX/CRH test, despite a reduction in depressive symptoms. Conclusions: This study provides evidence that, depending on gender and polymorphisms, there is continuous HPA axis overdrive in a proportion of patients irrespective of the status of depression. Considering the importance of stress hormones for cardiovascular disorders, our data might suggest that these patients are at high risk of comorbidity between depression and cardiovascular disorders. Copyright (c) 2008 S. Karger AG, Base

    Conicoid Mirrors

    Get PDF
    The first order equation relating object and image location for a mirror of arbitrary conic-sectional shape is derived. It is also shown that the parabolic reflecting surface is the only one free of aberration and only in the limiting case of distant sources.Comment: 9 page

    Numerical computation of real or complex elliptic integrals

    Full text link
    Algorithms for numerical computation of symmetric elliptic integrals of all three kinds are improved in several ways and extended to complex values of the variables (with some restrictions in the case of the integral of the third kind). Numerical check values, consistency checks, and relations to Legendre's integrals and Bulirsch's integrals are included

    Activation of PKA leads to mesenchymal-to-epithelial transition and loss of tumor-initiating ability

    Get PDF
    The epithelial-to-mesenchymal transition enables carcinoma cells to acquire malignancy-associated traits and the properties of tumor-initiating cells (TICs). TICs have emerged in recent years as important targets for cancer therapy, owing to their ability to drive clinical relapse and enable metastasis. Here, we propose a strategy to eliminate mesenchymal TICs by inducing their conversion to more epithelial counterparts that have lost tumor-initiating ability. We report that increases in intracellular levels of the second messenger, adenosine 3',5'-monophosphate, and the subsequent activation of protein kinase A (PKA) induce a mesenchymal-to-epithelial transition (MET) in mesenchymal human mammary epithelial cells. PKA activation triggers epigenetic reprogramming of TICs by the histone demethylase PHF2, which promotes their differentiation and loss of tumor-initiating ability. This study provides proof-of-principle for inducing an MET as differentiation therapy for TICs and uncovers a role for PKA in enforcing and maintaining the epithelial state

    Assessing the energy implications of replacing car trips with bicycle trips in Sheffield, UK

    Get PDF
    A wide range of evidence supports policies which encourage people to cycle more and drive less, for health and environmental reasons. However, the likely energy implications of such a modal shift have remained relatively unexplored. In this paper we generate scenarios for increasing the cycling rate in Sheffield between 2010 and 2020. This is done through the novel application of a simple model, borrowed from population ecology. The analysis suggests that pro-cycling interventions result in energy savings through reduced consumption of fuel and cars, and energy costs through increased demand for food. The cumulative impact is a net reduction in primary energy consumption, the magnitude of which depends on a number of variables which are subject to uncertainty. Based on the evidence presented and analysed in this paper, we conclude that transport policy has a number of important energy implications, some of which remain unexplored. We therefore advocate the formation of closer links between energy policy and transport policy in academia and in practice; our approach provides a simple yet flexible framework for pursuing this aim in the context of modal shift

    The Awesome Power of Yeast Evolutionary Genetics: New Genome Sequences and Strain Resources for the Saccharomyces sensu stricto Genus

    Get PDF
    High-quality, well-annotated genome sequences and standardized laboratory strains fuel experimental and evolutionary research. We present improved genome sequences of three species of Saccharomyces sensu stricto yeasts: S. bayanus var. uvarum (CBS 7001), S. kudriavzevii (IFO 1802T and ZP 591), and S. mikatae (IFO 1815T), and describe their comparison to the genomes of S. cerevisiae and S. paradoxus. The new sequences, derived by assembling millions of short DNA sequence reads together with previously published Sanger shotgun reads, have vastly greater long-range continuity and far fewer gaps than the previously available genome sequences. New gene predictions defined a set of 5261 protein-coding orthologs across the five most commonly studied Saccharomyces yeasts, enabling a re-examination of the tempo and mode of yeast gene evolution and improved inferences of species-specific gains and losses. To facilitate experimental investigations, we generated genetically marked, stable haploid strains for all three of these Saccharomyces species. These nearly complete genome sequences and the collection of genetically marked strains provide a valuable toolset for comparative studies of gene function, metabolism, and evolution, and render Saccharomyces sensu stricto the most experimentally tractable model genus. These resources are freely available and accessible through www.SaccharomycesSensuStricto.org

    Extra patient movement during mammographic imaging : an experimental study

    Get PDF
    Objectives: To determine if movement external to the patient occurring during mammography may be a source of image blur. Methods: Four mammography machines with seven flexible and nine fixed paddles were evaluated. In the first stage, movement at the paddle was measured mechanically using two calibrated linear potentiometers. A deformable breast phantom was used to mimic a female breast. For each paddle, the movement in millimeters and change in compression force in Newton was recorded at 0.5 and 1 second intervals respectively for 40 seconds with the phantom in an initially compressed state under a load of 80N. In the second stage, clinical audit on 28 females was conducted on one mammography machine with the 18x24cm and 24x29cm flexible paddles. Results: Movement at the paddle followed an exponential decay with a settling period of approximately 40 seconds. The compression force readings for both fixed and flexible paddles decreased exponentially with time while fixed paddles have a larger drop in compression force than flexible paddles. There is a linear relationship between movement at the paddle and change in compression force. Conclusions: Movement measured at the paddle during an exposure can be represented by a second order system. The amount of extra-patient movement during the actual exposure can be estimated using the linear relationship between movement at the paddle and the change in compression force. Advances in knowledge: This research provides a possible explanation to mammography image blurring caused by extra patient movement and proposes a theoretical model to analyze the movement

    Photo-CIDNP in the reaction center of the diatom Cyclotella meneghiniana observed by 13C MAS NMR

    Get PDF
    Solid state NMR/Biophysical Organic Chemistr
    corecore