32 research outputs found

    Innate Immune Response to Rift Valley Fever Virus in Goats

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    Rift Valley fever (RVF), a re-emerging mosquito-borne disease of ruminants and man, was endemic in Africa but spread to Saudi Arabia and Yemen, meaning it could spread even further. Little is known about innate and cell-mediated immunity to RVF virus (RVFV) in ruminants, which is knowledge required for adequate vaccine trials. We therefore studied these aspects in experimentally infected goats. We also compared RVFV grown in an insect cell-line and that grown in a mammalian cell-line for differences in the course of infection. Goats developed viremia one day post infection (DPI), which lasted three to four days and some goats had transient fever coinciding with peak viremia. Up to 4% of peripheral blood mononuclear cells (PBMCs) were positive for RVFV. Monocytes and dendritic cells in PBMCs declined possibly from being directly infected with virus as suggested by in vitro exposure. Infected goats produced serum IFN-γ, IL-12 and other proinflammatory cytokines but not IFN-α. Despite the lack of IFN-α, innate immunity via the IL-12 to IFN-γ circuit possibly contributed to early protection against RVFV since neutralising antibodies were detected after viremia had cleared. The course of infection with insect cell-derived RVFV (IN-RVFV) appeared to be different from mammalian cell-derived RVFV (MAM-RVFV), with the former attaining peak viremia faster, inducing fever and profoundly affecting specific immune cell subpopulations. This indicated possible differences in infections of ruminants acquired from mosquito bites relative to those due to contact with infectious material from other animals. These differences need to be considered when testing RVF vaccines in laboratory settings

    Influence of elevated radiative lifetime on efficiency of CdSe/CdTe Type II colloidal quantum dot based solar cells

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    Colloidal quantum dots (CQDs) are promising materials for solar cells because their optoelectronic properties are easily adjusted by control of their size, structure and composition. We present calculations of the band gap and radiative lifetime for varying core diameter and shell thickness of CdSe/CdTe core/shell Type II CQDs using a combination of single particle (2,6)-band k·pk·p and many-electron configuration interaction (CI) Hamiltonians. These calculations are validated by comparison with experimental absorption spectra and photoluminescence decay data. The results are then incorporated into a model of photovoltaic efficiency which demonstrates how the overall performance of a solar cell based on Type II CQDs is affected by changes in the core/shell geometry. The largest effect on photovoltaic efficiency is found to be due to the longer radiative lifetime produced by increasing the shell thickness

    Supercritical CO2 Extraction as an Effective Pretreatment Step for Wax Extraction in a Miscanthus Biorefinery

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    The use of supercritical carbon dioxide (scCO2) to extract valuable lipophilic compounds from miscanthus was investigated and subsequent enzymatic saccharification was carried out to determine the impact of scCO2 extraction on downstream processing of miscanthus. Two miscanthus genotypes (Miscanthus x. giganteus and Miscanthus sinensis) were investigated and characterized. A diverse range of molecules were detected including long-chain hydrocarbons, fatty acids, n-policosanols, aldehydes, wax esters, sterols and steroid ketones. Quantification data indicates that there is a considerable difference among each species in the quantities of specific compounds. The waxes also exhibited significant differences in melting temperature, thus illustrating the opportunity for utilization in various applications. In addition to the isolation of valuable chemical compounds, the scCO2 pretreatment also had a beneficial effect on the downstream processing of the biomass. The total sugars released after saccharification was found to increase by around 20% when coupled with scCO2 extraction, as compared to untreated samples.</p

    Past changes in the vertical distribution of ozone: Part 1: Measurement techniques, uncertainties and availability

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    Peak stratospheric chlorofluorocarbon (CFC) and other ozone depleting substance (ODS) concentrations were reached in the mid- to late 1990s. Detection and attribution of the expected recovery of the stratospheric ozone layer in an atmosphere with reduced ODSs as well as efforts to understand the evolution of stratospheric ozone in the presence of increasing greenhouse gases are key current research topics. These require a critical examination of the ozone changes with an accurate knowledge of the spatial (geographical and vertical) and temporal ozone response. For such an examination, it is vital that the quality of the measurements used be as high as possible and measurement uncertainties well quantified. In preparation for the 2014 United Nations Environment Programme (UNEP)/World Meteorological Organization (WMO) Scientific Assessment of Ozone Depletion, the SPARC/IO3C/IGACO-O3/NDACC (SI2N) Initiative was designed to study and document changes in the global ozone profile distribution. This requires assessing long-term ozone profile data sets in regards to measurement stability and uncertainty characteristics. The ultimate goal is to establish suitability for estimating long-term ozone trends to contribute to ozone recovery studies. Some of the data sets have been improved as part of this initiative with updated versions now available. This summary presents an overview of stratospheric ozone profile measurement data sets (ground and satellite based) available for ozone recovery studies. Here we document measurement techniques, spatial and temporal coverage, vertical resolution, native units and measurement uncertainties. In addition, the latest data versions are briefly described (including data version updates as well as detailing multiple retrievals when available for a given satellite instrument). Archive location information for each data set is also given.ISSN:1867-1381ISSN:1867-854

    As fotografias de "anjos" no Brasil do século XIX

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    This paper examines the photographs of dead children taken in SĂŁo Paulo in the\ud 19th century, as a means to understand the sensibilities in relation to death at the time as well\ud as certain changes that occurred in this domain. The analytical strategy adopted by the author\ud focuses on the identification, in the photographic material, of the elements that constituted the\ud practices and representations relating to deceased children, the origins of which are far older\ud than the practice of photographing angels. Likewise, he looks into the elements associated\ud with the changes that took place in this sphere during the second half of the 19th century,\ud which he believes accompanied and fostered not only the advent but also the extinction of\ud this custo
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