522 research outputs found

    Neutralising antibody response in domestic cats immunised with a commercial feline immunodeficiency virus (FIV) vaccine

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    Across human and veterinary medicine, vaccines against only two retroviral infections have been brought to market successfully, the vaccines against feline leukaemia virus (FeLV) and feline immunodeficiency virus (FIV). FeLV vaccines have been a global success story, reducing virus prevalence in countries where uptake is high. In contrast, the more recent FIV vaccine was introduced in 2002 and the degree of protection afforded in the field remains to be established. However, given the similarities between FIV and HIV, field studies of FIV vaccine efficacy are likely to advise and inform the development of future approaches to HIV vaccination.<p></p> Here we assessed the neutralising antibody response induced by FIV vaccination against a panel of FIV isolates, by testing blood samples collected from client-owned vaccinated Australian cats. We examined the molecular and phenotypic properties of 24 envs isolated from one vaccinated cat that we speculated might have become infected following natural exposure to FIV. Cats vaccinated against FIV did not display broadly neutralising antibodies, suggesting that protection may not extend to some virulent recombinant strains of FIV circulating in Australia.<p></p&gt

    A method for atomic layer deposition of complex oxide thin films

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    Advanced technologies derive many of their capabilities from the advanced materials that they are made from. Complex oxides are a class of materials which are driving technological advancement in a host of di erent directions. These highly functional materials have a great variety of useful properties, which can be chosen and even engineered.Advanced materials require advanced deposition methods. Atomic layer deposition (ALD), a variant of chemical vapor deposition (CVD), is gaining more use in industry for its ability to provide ultra-high lm thickness resolution (down to 0.1 nm), capability to conformally coat three-dimensional structures, and its high uniformity across large surface areas. Additionally, ALD processes provide a possibility to improve economic and environmental viability of the process as compared to CVD by using and wasting less toxic reactants and expelling fewer nano-particulate byproducts.ALD processes are highly mature for many binary oxides commonly used in the semiconductor industries, however processes for depositing heavy metal oxides and complex oxides - oxides containing two or more separate metallic cations | are sorely lacking in literature.The primary focus of this work is the development of a process for depositing the complex perovskite oxide lead titanate (PbTiO3), an end group of the lead zirconate titanate family (PbZrxTi1-xO3), which has valuable technical applications as well as serves as a template for applying this research into other material systems.The author gratefully acknowledges the Army Research O ce (ARO) for their support of this project under the funding provided by Grant # W911NF-08-1-0067.M.S., Materials Science and Engineering -- Drexel University, 201

    From Opportunity to Necessity: Development of an Asynchronous Online Interprofessional Learning Experience

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    Incorporating interprofessional collaboration competencies into both undergraduate pre-licensure and graduate health science students poses challenges for academic health science centers. Certain student groups may have less opportunity to participate in interprofessional learning experiences due to demands of individual programs of study and conflicts in scheduling time with other disciplines. A group of interprofessional higher education faculty members created an innovative online asynchronous interprofessional experience with the primary goals of meeting accreditation standards for specific programs and providing interprofessional education (IPE) to students who were unable to participate in traditional face-to-face IPE experiences already established at the institution. This guide will highlight the process of design and development of the learning opportunity, from conception to implementation. The pilot of the asynchronous online IPE experience served as a model for the transition of the original in-person model to virtual IPE during the COVID-19 pandemic

    The tempo of cetacean cranial evolution

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    The evolution of cetaceans (whales and dolphins) represents one of the most extreme adaptive transitions known, from terrestrial mammals to a highly specialized aquatic radiation that includes the largest animals alive today. Many anatomical shifts in this transition involve the feeding, respiratory, and sensory structures of the cranium, which we quantified with a high-density, three-dimensional geometric morphometric analysis of 201 living and extinct cetacean species spanning the entirety of their ∼50-million-year evolutionary history. Our analyses demonstrate that cetacean suborders occupy distinct areas of cranial morphospace, with extinct, transitional taxa bridging the gap between archaeocetes (stem whales) and modern mysticetes (baleen whales) and odontocetes (toothed whales). This diversity was obtained through three key periods of rapid evolution: first, the initial evolution of archaeocetes in the early to mid-Eocene produced the highest evolutionary rates seen in cetaceans, concentrated in the maxilla, frontal, premaxilla, and nasal; second, the late Eocene divergence of the mysticetes and odontocetes drives a second peak in rates, with high rates and disparity sustained through the Oligocene; and third, the diversification of odontocetes, particularly sperm whales, in the Miocene (∼18-10 Mya) propels a final peak in the tempo of cetacean morphological evolution. Archaeocetes show the fastest evolutionary rates but the lowest disparity. Odontocetes exhibit the highest disparity, while mysticetes evolve at the slowest pace, particularly in the Neogene. Diet and echolocation have the strongest influence on cranial morphology, with habitat, size, dentition, and feeding method also significant factors impacting shape, disparity, and the pace of cetacean cranial evolution

    Too Little, Too Late: How the Tidal Evolution of Hot Jupiters affects Transit Surveys of Clusters

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    The tidal evolution of hot Jupiters may change the efficiency of transit surveys of stellar clusters. The orbital decay that hot Jupiters suffer may result in their destruction, leaving fewer transiting planets in older clusters. We calculate the impact tidal evolution has for different assumed stellar populations, including that of 47~Tuc, a globular cluster that was the focus of an intense HST search for transits. We find that in older clusters one expects to detect fewer transiting planets by a factor of two for surveys sensitive to Jupiter-like planets in orbits out to 0.5~AU, and up to a factor of 25 for surveys sensitive to Jupiter-like planets in orbits out to 0.08~AU. Additionally, tidal evolution affects the distribution of transiting planets as a function of semi-major axis, producing larger orbital period gaps for transiting planets as the age of the cluster increases. Tidal evolution can explain the lack of detected exoplanets in 47~Tuc without invoking other mechanisms. Four open clusters residing within the {\em Kepler} fields of view have ages that span 0.4-8~Gyr--if {\em Kepler} can observe a significant number of planets in these clusters, it will provide key tests for our tidal evolution hypothesis. Finally, our results suggest that observers wishing to discover transiting planets in clusters must have sufficient accuracy to detect lower mass planets, search larger numbers of cluster members, or have longer observation windows to be confident that a significant number of transits will occur for a population of stars.Comment: 23 pages including 6 figures, accepted to Ap

    The J-2X Oxidizer Turbopump - Design, Development, and Test

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    Pratt and Whitney Rocketdyne (PWR), a NASA subcontractor, is executing the Design, Development, Test, and Evaluation (DDT&E) of a liquid oxygen, liquid hydrogen two hundred ninety-four thousand pound thrust rocket engine initially intended for the Upper Stage (US) and Earth Departure Stage (EDS) of the Constellation Program Ares-I Crew Launch Vehicle (CLV). A key element of the design approach was to base the new J-2X engine on the heritage J-2S engine which was a design upgrade of the flight proven J-2 engine used to put American astronauts on the moon. This paper will discuss the design trades and analyses performed to achieve the required uprated Oxidizer Turbopump performance; structural margins and rotordynamic margins; incorporate updated materials and fabrication capability; and reflect lessons learned from legacy and existing Liquid Rocket Propulsion Engine turbomachinery. These engineering design, analysis, fabrication and assembly activities support the Oxidizer Turbopump readiness for J-2X engine test in 2011
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