23 research outputs found

    Investigating the thermal stability of 1-3 piezoelectric composite transducers by varying the thermal conductivity and glass transition temperature of the polymeric filler material

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    The thermal behaviour of a number of 1-3 piezoelectric composite transducers is discussed. In particular, devices manufactured from a polymer filler with a relatively high glass to rubber transition temperature (T-g), and from polymer systems with increased thermal conductivity, are evaluated. The mechanical properties of the various filler materials were obtained via ultrasonic measurements, with the thermal properties extracted using dynamic mechanical thermal analysis (dmta), differential scanning calorimetry (dsc) and laserflash studies. A range of ultrasonic transducers were then constructed and their thermal stability studied using a combination of impedance analysis and laser surface displacement measurement

    Knowledge gaps that hamper prevention and control of Mycobacterium avium subspecies paratuberculosis infection

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    In the last decades, many regional and country‐wide control programmes for Johne's disease (JD) were developed due to associated economic losses, or because of a possible association with Crohn's disease. These control programmes were often not successful, partly because management protocols were not followed, including the introduction of infected replacement cattle, because tests to identify infected animals were unreliable, and uptake by farmers was not high enough because of a perceived low return on investment. In the absence of a cure or effective commercial vaccines, control of JD is currently primarily based on herd management strategies to avoid infection of cattle and restrict within‐farm and farm‐to‐farm transmission. Although JD control programmes have been implemented in most developed countries, lessons learned from JD prevention and control programmes are underreported. Also, JD control programmes are typically evaluated in a limited number of herds and the duration of the study is less than 5 year, making it difficult to adequately assess the efficacy of control programmes. In this manuscript, we identify the most important gaps in knowledge hampering JD prevention and control programmes, including vaccination and diagnostics. Secondly, we discuss directions that research should take to address those knowledge gaps.http://wileyonlinelibrary.com/journal/tbed2019-05-01hj2018Veterinary Tropical Disease

    Ruth Gipps: Anti-Modernism, Nationalism and Difference in English Music

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    Signaling through the mammalian target of rapamycin complex 1 (mTORC1) is positively regulated by amino acids and insulin. PRAS40 associates with mTORC1 (which contains raptor) but not mTORC2. PRAS40 interacts with raptor, and this requires an intact TOR-signaling (TOS) motif in PRAS40. Like TOS motif-containing proteins such as eIF4E-binding protein 1 (4E-BP1), PRAS40 is a substrate for phosphorylation by mTORC1. Consistent with this, starvation of cells of amino acids or treatment with rapamycin alters the phosphorylation of PRAS40. PRAS40 binds 14-3-3 proteins, and this requires both amino acids and insulin. Binding of PRAS40 to 14-3-3 proteins is inhibited by TSC1/2 (negative regulators of mTORC1) and stimulated by Rheb in a rapamycin-sensitive manner. This confirms that PRAS40 is a target for regulation by mTORC1. Small interfering RNA-mediated knockdown of PRAS40 impairs both the amino acid- and insulin-stimulated phosphorylation of 4E-BP1 and the phosphorylation of S6. However, this has no effect on the phosphorylation of Akt or TSC2 (an Akt substrate). These data place PRAS40 downstream of mTORC1 but upstream of its effectors, such as S6K1 and 4E-BP1

    Efficacy of novel lipid-formulated whole bacterial cell vaccines against Mycobacterium avium subsp paratuberculosis in sheep

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    Mycobacterium avium subsp. paratuberculosis [MAP], the Causative agent of enteric Johne's disease, incurs significant economic losses to the livestock industry. Prophylactic vaccination can be employed as a control means, however mineral oil-based vaccines Currently in practice have limited efficacy, produce strong antibody responses that confound serological diagnostic testing, and cause severe injection site reactions. In the present study, the safety and efficacy of a commercial mineral oil-adjuvanted vaccine (Gudair (TM)) was compared with novel parenteral-route vaccines in sheep: these comprised live or heat-killed (HK) whole cell preparations of MAP strain 316F, formulated into a food-grade lipid vaccine delivery matrix. Subcutaneous administration of lipid-formulated live or I HK 316F-induced significantly fewer adverse injection site reactions than Gudair (TM); adverse injection site reactions were eliminated altogether by intraperitoneal (i.p.) injection of lipid-formulated live 316F Injections of lipid-formulated 316F-induced significant peripheral blood cell-mediated immune (CMI) responses in the absence of antibody, while Gudair (TM)-induced strong antibody and CMI reactivity. Vaccinated and non-vaccinated control sheep were challenged via oral inoculation of a virulent MAP isolate, and disease progress was monitored for 16 months, followed by necropsy. All vaccine regimes reduced the overall pathological grading of biopsied intestinal tract (IT) tissues; among these, only Gudair (TM) promoted a significant reduction in the incidence of histopathological IT lesions, while only i.p. injection of lipid-formulated live 316F significantly reduced the incidence of gross IT lesions. All lipid-formulated vaccines (but not Gudair (TM)) significantly reduced the incidence of bacteriological culture-confirmed MAP infection. This study identifies a new vaccination strategy against Johne's disease in sheep using conventional MAP vaccine strains formulated in a metabolisable lipid delivery matrix. (C) 2008 Published by Elsevier Ltd

    Immunological and molecular characterization of susceptibility in relationship to bacterial strain differences in Mycobacterium avium subsp paratuberculosis infection in the red deer (Cervus elaphus)

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    Johne's disease (JD) infection, caused by Mycobacterium avium subsp. paratuberculosis, represents a major disease problem in farmed ruminants. Although JD has been well characterized in cattle and sheep, little is known of the infection dynamics or immunological response in deer. In this study, typing of M. avium subsp. paratuberculosis isolates from intestinal lymphatic tissues from 74 JD-infected animals showed that clinical isolates of M. avium subsp. paratuberculosis from New Zealand farmed red deer were exclusively of the bovine strain genotype. The susceptibility of deer to M. avium subsp. paratuberculosis was further investigated by experimental oral-route infection studies using defined isolates of virulent bovine and ovine M. avium subsp. paratuberculosis strains. Oral inoculation with high (109 CFU/animal) or medium (107 CFU/animal) doses of the bovine strain of M. avium subsp. paratuberculosis established 100% infection rates, compared to 69% infection following inoculation with a medium dose of the ovine strain. The high susceptibility of deer to the bovine strain of M. avium subsp. paratuberculosis was confirmed by a 50% infection rate following experimental inoculation with a low dose of bacteria (103 CFU/animal). This study is the first to report experimental M. avium subsp. paratuberculosis infection in red deer, and it outlines the strong infectivity of bovine-strain M. avium subsp. paratuberculosis isolates for cervines
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