1,345 research outputs found

    A homoleptic phosphine adduct of Tl(I)

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    A homoleptic phosphine adduct of thallium(I) supported by a tris(phosphino)borate ligand has been isolated and structurally characterized

    Amino acid changes in the spike protein of feline coronavirus correlate with systemic spread of virus from the intestine and not with feline infectious peritonitis

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    Recent evidence suggests that a mutation in the spike protein gene of feline coronavirus (FCoV), which results in an amino acid change from methionine to leucine at position 1058, may be associated with feline infectious peritonitis (FIP). Tissue and faecal samples collected post mortem from cats diagnosed with or without FIP were subjected to RNA extraction and quantitative reverse-transcriptase polymerase chain reaction (qRT-PCR) to detect FCoV RNA. In cats with FIP, 95% of tissue, and 81% of faecal samples were PCR-positive, as opposed to 22% of tissue, and 60% of faecal samples in cats without FIP. Relative FCoV copy numbers were significantly higher in the cats with FIP, both in tissues (P < 0.001) and faeces (P = 0.02). PCR-positive samples underwent pyrosequencing encompassing position 1058 of the FCoV spike protein. This identified a methionine codon at position 1058, consistent with the shedding of an enteric form of FCoV, in 77% of the faecal samples from cats with FIP, and in 100% of the samples from cats without FIP. In contrast, 91% of the tissue samples from cats with FIP and 89% from cats without FIP had a leucine codon at position 1058, consistent with a systemic form of FCoV. These results suggest that the methionine to leucine substitution at position 1058 in the FCoV spike protein is indicative of systemic spread of FCoV from the intestine, rather than a virus with the potential to cause FIP

    The NCBO OBOF to OWL Mapping

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    Two of the most significant formats for biomedical ontologies are the Open Biomedical Ontologies Format (OBOF) and the Web Ontology Language (OWL). To make it possible to translate ontologies between these two representation formats, the National Center for Biomedical Ontology (NCBO) has developed a mapping between the OBOF and OWL formats as well as inter-conversion software. The goal was to allow the sharing of tools, ontologies, and associated data between the OBOF and Semantic Web communities.&#xd;&#xa;&#xd;&#xa;OBOF does not have a formal grammar, so the NCBO had to capture its intended semantics to map it to OWL.&#xd;&#xa;&#xd;&#xa;This official NCBO mapping was used to make all OBO Foundry ontologies available in OWL. &#xd;&#xa;&#xd;&#xa;Availability: This mapping functionality can be embedded into OBO-Edit and Prote&#x301;ge&#x301;-OWL ontology editors. This software is available at: http://bioontology.org/wiki/index.php/OboInOwl:Main_Pag

    Combining uretdione and disulfide reversibly degradable polyurethanes : route to alternating block copolymers

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    Uretdione (temperature and catalyst controlled) and disulphide (REDOX controlled) functionalised polyurethanes have been described and the reversibility of these bonds tested. The polymers have been synthesised with reversible covalent groups present throughout their backbone, developing routes to reversibly degradable polyurethanes. These materials degrade and reheal in response to different external stimuli, which supplies a proof of concept for controlling the molecular weight, and therefore, the physical properties of a polyurethane. Further, a unique route to an alternating block copolymer is also discussed that utilises a mixture of disulphide and uretdione functionalised polymers as the reagents to form a thiourethane. The dramatically reduced safety hazards of dealing with the functionalised polymers, in comparison to the free isocyanate and thiols, could be of great interest to industrial application for current drives towards safer routes to polyurethanes

    Association of the tumour necrosis factor alpha -308 but not the interleukin 10 -627 promoter polymorphism with genetic susceptibility to primary sclerosing cholangitis

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    BACKGROUND AND AIMS Primary sclerosing cholangitis (PSC) is a chronic cholestatic liver disease of unknown aetiology. Abnormalities in immune regulation and genetic associations suggest that PSC is an immune mediated disease. Several polymorphisms within the tumour necrosis factor α (TNF-α) and interleukin 10 (IL-10) promoter genes have been described which influence expression of these cytokines. This study examines the possible association between polymorphisms at the −308 and −627 positions in the TNF-α and IL-10 promoter genes, respectively, and susceptibility to PSC. METHODS TNF-α −308 genotypes were studied by polymerase chain reaction (PCR) in 160 PSC patients from Norway and the UK compared with 145 ethnically matched controls. IL-10 −627 genotypes were studied by PCR in 90 PSC patients compared with 84 ethnically matched controls. RESULTS A total of 16% of Norwegian PSC patients and 12% of British PSC patients were homozygous for the TNF2 allele compared with 3% and 6% of respective controls. The TNF2 allele was present in 60% of PSC patients versus 30% of controls (ORcombined data=3.2 (95% confidence intervals (CI) 1.8–4.5); pcorr=10−5). The association between the TNF2 allele and susceptibility to PSC was independent of the presence of concurrent inflammatory bowel disease (IBD) in the PSC patients; 61% of PSC patients without IBD had TNF2 compared with 30% of controls (ORcombined data=3.2 (95% CI 1.2–9.0); pcorr=0.006 ). There was no difference in the −627 IL-10 polymorphism distributions between patients and controls in either population. The increase in TNF2 allele in PSC patients only occurs in the presence of DRB1*0301 (DR3) and B8. In the combined population data, DRB1*0301 showed a stronger association with susceptibility to PSC than both the TNF2 and B8 alleles (ORcombined data=3.8, pcorr=10−6 v ORcombined data=3.2, pcorr=10−5 vORcombined data =3.41, pcorr=10−4, respectively). CONCLUSIONS This study identified a significant association between possession of the TNF2 allele, a G→A substitution at position −308 in the TNF-α promoter, and susceptibility to PSC. This association was secondary to the association of PSC with the A1-B8-DRB1*0301-DQA1*0501-DQB1*0201 haplotype. No association was found between the IL-10 −627 promoter polymorphism and PSC

    Electronic Structures of Nitridomanganese(V) Complexes

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    The single-crystal polarized absorption and circular dichroism spectra of the nitridomanganese(V) complexes (salen)Mn⋮N (1), (1S,2S-(−)-saldpen)Mn⋮N (2), and (1R,2R-(+)-saldpen)Mn⋮N (3) have been measured [salen = N,N‘-ethylenebis(salicylideneaminato) dianion, 1S,2S-(−)-saldpen = N,N‘-(1S,2S-(−)-diphenyl)ethylenebis(salicylideneaminato) dianion, and 1R,2R-(+)-saldpen = N,N‘-(1R,2R-(+)-diphenyl)ethylenebis(salicylideneaminato) dianion]. As revealed by X-ray crystal structure analyses, these molecules have a distorted square-pyramidal geometry with a short Mn⋮N bond distance (1.52(3) Å for 2). The Cs compounds have a low-spin^ 1A‘[a‘(x^2 − y^2)]^2 ground state. The lowest absorption system (∼600 nm) consists of two components that are separated by approximately 4000 cm^(-1); these are assigned to ^1A‘ → ^1A‘[a‘(x^2 − y^2)a‘(yz)] (14 900 cm^(-1)) and ^1A‘ → ^1A‘‘[a‘(x^2 − y^2)a‘‘(xz)] (18 900 cm^(-1)) transitions

    The Implementation and Validation of a Virtual Environment for Training Powered Wheelchair Manoeuvres

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    This work has been submitted to the IEEE for possible publication. Copyright may be transferred without notice, after which this version may no longer be accessible.Navigating a powered wheelchair and avoiding collisions is often a daunting task for new wheelchair users. It takes time and practice to gain the coordination needed to become a competent driver and this can be even more of a challenge for someone with a disability. We present a cost-effective virtual reality (VR) application that takes advantage of consumer level VR hardware. The system can be easily deployed in an assessment centre or for home use, and does not depend on a specialized high-end virtual environment such as a Powerwall or CAVE. This paper reviews previous work that has used virtual environments technology for training tasks, particularly wheelchair simulation. We then describe the implementation of our own system and the first validation study carried out using thirty three able bodied volunteers. The study results indicate that at a significance level of 5% then there is an improvement in driving skills from the use of our VR system. We thus have the potential to develop the competency of a wheelchair user whilst avoiding the risks inherent to training in the real world. However, the occurrence of cybersickness is a particular problem in this application that will need to be addressed

    The effects of land use disturbance vary with trophic position in littoral cichlid fish communities from Lake Tanganyika

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    1. Impacts of anthropogenic disturbance are especially severe in freshwater ecosystems. In particular, land use disturbance can lead to increased levels of pollution, including elevated nutrient and sediment loads whose negative impacts range from the community to the individual level. However, few studies have investigated if these impacts are uniform across species represented by multiple trophic levels. To address this knowledge gap, we focused on Lake Tanganyika cichlid fishes, which comprise hundreds of species representing a wide range of feeding strategies. Cichlids are at their most diverse within the near‐shore environment; however, land use disturbance of this environment has led to decreasing diversity, particularly in herbivores. We therefore tested if there is a uniform effect of pollution across species and trophic groups within the hyper‐diverse rocky shore cichlid fish community. 2. We selected three sites with differing levels of human impact along the Tanzanian coastline and 10 cichlid species, comprising varying taxonomic and trophic groups, common to these sites. Nitrogen and carbon stable isotope values for 528 samples were generated and analysed using generalised linear mixed models. We also estimated stomach contents including sediment proportions. 3. Our study highlights that multiple sources of pollution are having differing effects across species within a diverse fish community. We found that nitrogen stable isotope values were significantly higher at the most disturbed (urbanised) site for benthic feeding species, whereas there was no difference in these isotopes between sites for the water column feeding trophic group. Stomach contents revealed that the elevated δ15N values were unlikely to have been caused by differences in diet between sites. However, at the most disturbed site, higher proportions of sediment were present in most herbivores, irrespective of foraging behaviour. 4. It is likely that anthropogenic nitrogen loading is the cause of higher nitrogen stable isotope values since there was no evidence of species shifting trophic levels between sites. Results support our previous study showing herbivore species to be most affected by human disturbance and make the link to pollution much more explicit. As lower diversity of consumers can negatively affect ecosystem processes such as stability, alleviating environmental impact through sewage treatment and afforestation programmes should continue to be a global priority for the conservation of aquatic ecosystems, as well as human health

    Design considerations for a background limited 350 micron pixel array using lumped element superconducting microresonators

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    Future submillimeter telescopes will demand arrays with ~ 10^6 pixels to fill the focal plane. MAKO is a 350 µm camera being developed to demonstrate the use of superconducting microresonators to meet the high multiplexing factors required for scaling to large-format arrays while offering background-limited single-pixel sensitivity. Candidate pixel designs must simultaneously meet many requirements. To achieve the desired noise equivalent powers it must efficiently absorb radiation, feature a high responsivity, and exhibit low intrinsic device noise. Additionally, the use of high resonator quality factors of order ~ 10^5 and resonant frequencies of order f_(res) ≈ 100 MHz are desirable in order to reduce the per-pixel bandwidth to a minimum set by telescope scan speeds. This allows a maximum number of pixels to be multiplexed in a fixed electronic bandwidth. Here we present measurement results of the first MAKO prototype array which meets these design requirements while demonstrating sufficient sensitivity for background-limited operation at ground-based, far-infrared telescopes
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