1,489 research outputs found

    Procedure for the Alignment of an Ultrasonic Beam for Nondestructive Applications

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    Most of the nondestructive evaluation (NDE) work using ultrasonic waves generally involves detection and sizing of flaws (e.g., cracks, voids, etc.), and analysis of waves scattering from boundaries with different elastic properties inside a material. Alignment of the ultrasonic measuring system by maximizing the amplitude of the received signal is adequate for these measurements. For characterization of the material properties, one must determine the elastic constants of the material. If the material is anisotropic (e.g., composites), assuming orthorhombic symmetry, one needs a complete set of 9 elastic constants for the characterization.</p

    Understanding the culture of antimicrobial prescribing in agriculture: a qualitative study of UK pig veterinary surgeons

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    Objectives The use of antimicrobials in food-producing animals has been linked with the emergence of antimicrobial resistance in bacterial populations, with consequences for animal and public health. This study explored the underpinning drivers, motivators and reasoning behind prescribing decisions made by veterinary surgeons working in the UK pig industry. Methods A qualitative interview study was conducted with 21 veterinary surgeons purposively selected from all UK pig veterinary surgeons. Thematic analysis was used to analyse transcripts. Results Ensuring optimum pig health and welfare was described as a driver for antimicrobial use by many veterinary surgeons and was considered a professional and moral obligation. Veterinary surgeons also exhibited a strong sense of social responsibility over the need to ensure that antimicrobial use was responsible. A close relationship between management practices, health and economics was evident, with improvements in management commonly identified as being potential routes to reduce antimicrobial usage; however, these were not always considered economically viable. The relationship with clients was identified as being a source of professional stress for practitioners due to pressure from farmers requesting antimicrobial prescriptions, and concern over poor compliance of antimicrobial administration by some farmers. Conclusions The drivers behind prescribing decisions by veterinary surgeons were complex and diverse. A combination of education, improving communication between veterinary surgeons and farmers, and changes in regulations, in farm management and in consumer/retailer demands may all be needed to ensure that antimicrobial prescribing is optimal and to achieve significant reductions in use

    The Milliarcsecond Structure of Radio Galaxies and Quasars

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    Hybrid maps of the nuclei of radio galaxies and quasars show a variety of morphologies. Among compact sources, two structures are common: an asymmetric, “core-jet” morphology (eg, 3C 273), and an “equal double” morphology with two separated, similar components (eg, CTD 93). The nuclei of extended, double radio galaxies generally have a core-jet morphology with the jet directed toward one of the outer components

    p70 S6 kinase and actin dynamics: A perspective

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    p70 S6 kinase (p70S6K), a member of the AGC serine/threonine kinase family, was initially identified as a key player, together with its downstream effector S6, in the regulation of cellular growth and survival. The p70S6K protein has emerged in recent years as a multifunctional protein which also regulates the actin cytoskeleton and thus plays a role in cell migration. This new function is through two important activities of p70S6K, namely actin cross-linking and Rac1 and Cdc42 activation. The testis is critically dependent on an intricate balance of fundamental cellular processes such as adhesion, migration, and differentiation. It is increasingly evident that Rho GTPases and actin binding proteins play fundamental roles in regulating spermatogenesis within the testis. In this review, we will discuss current findings of p70S6K in the control of actin cytoskeleton dynamics. In addition, the potential role of p70S6K in spermatogenesis and testicular function will be highlighted

    Whole-genome sequencing to understand the genetic architecture of common gene expression and biomarker phenotypes.

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    Initial results from sequencing studies suggest that there are relatively few low-frequency (&lt;5%) variants associated with large effects on common phenotypes. We performed low-pass whole-genome sequencing in 680 individuals from the InCHIANTI study to test two primary hypotheses: (i) that sequencing would detect single low-frequency-large effect variants that explained similar amounts of phenotypic variance as single common variants, and (ii) that some common variant associations could be explained by low-frequency variants. We tested two sets of disease-related common phenotypes for which we had statistical power to detect large numbers of common variant-common phenotype associations-11 132 cis-gene expression traits in 450 individuals and 93 circulating biomarkers in all 680 individuals. From a total of 11 657 229 high-quality variants of which 6 129 221 and 5 528 008 were common and low frequency (&lt;5%), respectively, low frequency-large effect associations comprised 7% of detectable cis-gene expression traits [89 of 1314 cis-eQTLs at P &lt; 1 × 10(-06) (false discovery rate ∼5%)] and one of eight biomarker associations at P &lt; 8 × 10(-10). Very few (30 of 1232; 2%) common variant associations were fully explained by low-frequency variants. Our data show that whole-genome sequencing can identify low-frequency variants undetected by genotyping based approaches when sample sizes are sufficiently large to detect substantial numbers of common variant associations, and that common variant associations are rarely explained by single low-frequency variants of large effect

    Best practice guidelines for the molecular genetic diagnosis of maturity-onset diabetes of the young

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    Member of the EMQN MODY group: Gisela GasparAIMS/HYPOTHESIS: Mutations in the GCK and HNF1A genes are the most common cause of the monogenic forms of diabetes known as 'maturity-onset diabetes of the young'. GCK encodes the glucokinase enzyme, which acts as the pancreatic glucose sensor, and mutations result in stable, mild fasting hyperglycaemia. A progressive insulin secretory defect is seen in patients with mutations in the HNF1A and HNF4A genes encoding the transcription factors hepatocyte nuclear factor-1 alpha and -4 alpha. A molecular genetic diagnosis often changes management, since patients with GCK mutations rarely require pharmacological treatment and HNF1A/4A mutation carriers are sensitive to sulfonylureas. These monogenic forms of diabetes are often misdiagnosed as type 1 or 2 diabetes. Best practice guidelines for genetic testing were developed to guide testing and reporting of results

    Suppression of ABCE1-mediated mRNA translation limits N-MYC-driven cancer progression

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    The ability of the N-MYC transcription factor to drive cancer progression is well demonstrated in neuroblastoma, the most common extracranial pediatric solid tumor, where MYCN amplification heralds a poor prognosis, with only 11% of high-risk patients surviving past 5 years. However, decades of attempts of direct inhibition of N-MYC or its paralogues has led to the conclusion that this protein is “undruggable.” Therefore, targeting pathways upregulated by N-MYC signaling presents an alternative therapeutic approach. Here, we show that MYCN-amplified neuroblastomas are characterized by elevated rates of protein synthesis and that high expression of ABCE1, a translation factor directly upregulated by N-MYC, is itself a strong predictor of poor clinical outcome. Despite the potent ability of N-MYC in heightening protein synthesis and malignant characteristics in cancer cells, suppression of ABCE1 alone selectively negated this effect, returning the rate of translation to baseline levels and significantly reducing the growth, motility, and invasiveness of MYCN-amplified neuroblastoma cells and patient-derived xenograft tumors in vivo. The growth of nonmalignant cells or MYCN-nonamplified neuroblastoma cells remained unaffected by reduced ABCE1, supporting a therapeutic window associated with targeting ABCE1. Neuroblastoma cells with c-MYC overexpression also required ABCE1 to maintain cell proliferation and translation. Taken together, ABCE1-mediated translation constitutes a critical process in the progression of N-MYC-driven and c-MYC-driven cancers that warrants investigations into methods of its therapeutic inhibition

    Very Cold Gas and Dark Matter

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    We have recently proposed a new candidate for baryonic dark matter: very cold molecular gas, in near-isothermal equilibrium with the cosmic background radiation at 2.73 K. The cold gas, of quasi-primordial abundances, is condensed in a fractal structure, resembling the hierarchical structure of the detected interstellar medium. We present some perspectives of detecting this very cold gas, either directly or indirectly. The H2_2 molecule has an "ultrafine" structure, due to the interaction between the rotation-induced magnetic moment and the nuclear spins. But the lines fall in the km domain, and are very weak. The best opportunity might be the UV absorption of H2_2 in front of quasars. The unexpected cold dust component, revealed by the COBE/FIRAS submillimetric results, could also be due to this very cold H2_2 gas, through collision-induced radiation, or solid H2_2 grains or snowflakes. The γ\gamma-ray distribution, much more radially extended than the supernovae at the origin of cosmic rays acceleration, also points towards and extended gas distribution.Comment: 16 pages, Latex pages, crckapb macro, 3 postscript figures, uuencoded compressed tar file. To be published in the proceeedings of the "Dust-Morphology" conference, Johannesburg, 22-26 January, 1996, D. Block (ed.), (Kluwer Dordrecht

    Rapid isolation of mycoviral double-stranded RNA from Botrytis cinerea and Saccharomyces cerevisiae

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    <p>Abstract</p> <p>Background</p> <p>In most of the infected fungi, the mycoviruses are latent or cryptic, the infected fungus does not show disease symptoms, and it is phenotypically identical to a non-infected strain of the same species. Because of these properties, the initial stage in the search for fungi infected with mycoviruses is the detection of their viral genome, which in most of the described cases corresponds to double-stranded RNA (dsRNA). So to analyze a large number of fungal isolates it is necessary to have a simple and rapid method to detect dsRNA.</p> <p>Results</p> <p>A rapid method to isolate dsRNA from a virus-infected filamentous fungus, <it>Botrytis cinerea</it>, and from a killer strain of <it>Saccharomyces cerevisiae </it>using commercial minicolumns packed with CF11 cellulose was developed. In addition to being a rapid method, it allows to use small quantities of yeasts or mycelium as starting material, being obtained sufficient dsRNA quantity that can later be analyzed by agarose gel electrophoresis, treated with enzymes for its partial characterization, amplified by RT-PCR and cloned in appropriate vectors for further sequencing.</p> <p>Conclusions</p> <p>The method yields high quality dsRNA, free from DNA and ssRNA. The use of nucleases to degrade the DNA or the ssRNA is not required, and it can be used to isolate dsRNA from any type of fungi or any biological sample that contains dsRNA.</p

    CMB Telescopes and Optical Systems

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    The cosmic microwave background radiation (CMB) is now firmly established as a fundamental and essential probe of the geometry, constituents, and birth of the Universe. The CMB is a potent observable because it can be measured with precision and accuracy. Just as importantly, theoretical models of the Universe can predict the characteristics of the CMB to high accuracy, and those predictions can be directly compared to observations. There are multiple aspects associated with making a precise measurement. In this review, we focus on optical components for the instrumentation used to measure the CMB polarization and temperature anisotropy. We begin with an overview of general considerations for CMB observations and discuss common concepts used in the community. We next consider a variety of alternatives available for a designer of a CMB telescope. Our discussion is guided by the ground and balloon-based instruments that have been implemented over the years. In the same vein, we compare the arc-minute resolution Atacama Cosmology Telescope (ACT) and the South Pole Telescope (SPT). CMB interferometers are presented briefly. We conclude with a comparison of the four CMB satellites, Relikt, COBE, WMAP, and Planck, to demonstrate a remarkable evolution in design, sensitivity, resolution, and complexity over the past thirty years.Comment: To appear in: Planets, Stars and Stellar Systems (PSSS), Volume 1: Telescopes and Instrumentatio
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