1,113 research outputs found

    Brauer-Thrall for totally reflexive modules over local rings of higher dimension

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    Let RR be a commutative Noetherian local ring. Assume that RR has a pair {x,y}\{x,y\} of exact zerodivisors such that dimR/(x,y)2\dim R/(x,y)\ge2 and all totally reflexive R/(x)R/(x)-modules are free. We show that the first and second Brauer--Thrall type theorems hold for the category of totally reflexive RR-modules. More precisely, we prove that, for infinitely many integers nn, there exists an indecomposable totally reflexive RR-module of multiplicity nn. Moreover, if the residue field of RR is infinite, we prove that there exist infinitely many isomorphism classes of indecomposable totally reflexive RR-modules of multiplicity nn.Comment: to appear in Algebras and Representation Theor

    Whole genome sequence comparison of avian pathogenic Escherichia coli from acute and chronic salpingitis of egg laying hens.

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    BACKGROUND:Infection in the oviduct (salpingitis) is the most common bacterial infection in egg laying hens and is mainly caused by Escherichia coli. The disease is responsible for decreased animal welfare, considerable economic loss as well as a risk of horizontal and vertical transmission of pathogenic E. coli. The outcome of salpingitis may be either acute or chronic. It has not yet been clarified whether the pathological manifestation is a result of the characteristics of the E. coli or whether the manifestation is associated with host factors such as host immunity. RESULTS:From the core- and accessory genome analysis and comparison of 62 E. coli no genetic markers were found to be associated to either acute or chronic infection. Twenty of the 62 genomes harboured at least one antimicrobial resistance gene with resistance against sulfonamides being the most common. The increased serum survival and iron chelating genes iss and iroN were highly prevalent in genomes from both acute and chronic salpingitis. CONCLUSION:Our analysis revealed that no genetic markers could differentiate the E. coli isolated from acute versus chronic salpingitis in egg laying hens. The difference in pathological outcome may be related to other factors such as immunological status, genetics and health of the host. These data indicate that salpingitis is another manifestation of colibacillosis

    Decisions at the end of life: have we come of age?

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    Decision making is a complex process and it is particularly challenging to make decisions with, or for, patients who are near the end of their life. Some of those challenges will not be resolved - due to our human inability to foresee the future precisely and the human proclivity to change stated preferences when faced with reality. Other challenges of the decision-making process are manageable. This commentary offers a set of approaches which may lead to progress in this field

    Pancytopenia due to iron deficiency worsened by iron infusion: a case report

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    <p>Abstract</p> <p>Introduction</p> <p>Iron deficiency anemia is commonly associated with thrombocytosis, although thrombocytopenia has been reported in occasional patients with iron-deficiency anemia. Much less common is the development of thrombocytopenia following replenishment of iron stores.</p> <p>Case Presentation</p> <p>We present the unusual case of a 39 year old African American female Jehovah's Witness who presented with a 10 month history of menorrhagia and pancytopenia. Laboratory investigations confirmed a severe iron deficiency. Since blood transfusion was unacceptable to her, she was started on intravenous iron replacement therapy. This precipitated a sudden drop in both her platelet and white blood cell counts. Histopathological examination of the bone marrow revealed a hypercellular marrow with orderly trilineage hematopoiesis, iron deficiency anemia, granulocytic hyperplasia, and mild megakaryocytic hypoplasia. Both her white blood cell and platelet counts recovered uneventfully with continuing iron supplementation. The possible mechanism for this phenomenon is discussed in this report.</p> <p>Conclusion</p> <p>This case illustrates two rather uncommon associations of a very common problem. Severe iron deficiency anemia may be associated with pancytopenia and iron replacement may cause a transient decline in megakaryopoiesis and leukopoiesis. Severe iron deficiency should be added to the list of conditions leading to thrombocytopenia.</p

    Influenza nucleoprotein delivered with aluminium salts protects mice from an influenza virus that expresses an altered nucleoprotein sequence

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    Influenza virus poses a difficult challenge for protective immunity. This virus is adept at altering its surface proteins, the proteins that are the targets of neutralizing antibody. Consequently, each year a new vaccine must be developed to combat the current recirculating strains. A universal influenza vaccine that primes specific memory cells that recognise conserved parts of the virus could prove to be effective against both annual influenza variants and newly emergent potentially pandemic strains. Such a vaccine will have to contain a safe and effective adjuvant that can be used in individuals of all ages. We examine protection from viral challenge in mice vaccinated with the nucleoprotein from the PR8 strain of influenza A, a protein that is highly conserved across viral subtypes. Vaccination with nucleoprotein delivered with a universally used and safe adjuvant, composed of insoluble aluminium salts, provides protection against viruses that either express the same or an altered version of nucleoprotein. This protection correlated with the presence of nucleoprotein specific CD8 T cells in the lungs of infected animals at early time points after infection. In contrast, immunization with NP delivered with alum and the detoxified LPS adjuvant, monophosphoryl lipid A, provided some protection to the homologous viral strain but no protection against infection by influenza expressing a variant nucleoprotein. Together, these data point towards a vaccine solution for all influenza A subtypes

    Molecular cloning and transcriptional activity of a new Petunia calreticulin gene involved in pistil transmitting tract maturation, progamic phase, and double fertilization

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    Calreticulin (CRT) is a highly conserved and ubiquitously expressed Ca2+-binding protein in multicellular eukaryotes. As an endoplasmic reticulum-resident protein, CRT plays a key role in many cellular processes including Ca2+ storage and release, protein synthesis, and molecular chaperoning in both animals and plants. CRT has long been suggested to play a role in plant sexual reproduction. To begin to address this possibility, we cloned and characterized the full-length cDNA of a new CRT gene (PhCRT) from Petunia. The deduced amino acid sequence of PhCRT shares homology with other known plant CRTs, and phylogenetic analysis indicates that the PhCRT cDNA clone belongs to the CRT1/CRT2 subclass. Northern blot analysis and fluorescent in situ hybridization were used to assess PhCRT gene expression in different parts of the pistil before pollination, during subsequent stages of the progamic phase, and at fertilization. The highest level of PhCRT mRNA was detected in the stigma–style part of the unpollinated pistil 1 day before anthesis and during the early stage of the progamic phase, when pollen is germinated and tubes outgrow on the stigma. In the ovary, PhCRT mRNA was most abundant after pollination and reached maximum at the late stage of the progamic phase, when pollen tubes grow into the ovules and fertilization occurs. PhCRT mRNA transcripts were seen to accumulate predominantly in transmitting tract cells of maturing and receptive stigma, in germinated pollen/growing tubes, and at the micropylar region of the ovule, where the female gametophyte is located. From these results, we suggest that PhCRT gene expression is up-regulated during secretory activity of the pistil transmitting tract cells, pollen germination and outgrowth of the tubes, and then during gamete fusion and early embryogenesis

    Asteroseismology

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    Asteroseismology is the determination of the interior structures of stars by using their oscillations as seismic waves. Simple explanations of the astrophysical background and some basic theoretical considerations needed in this rapidly evolving field are followed by introductions to the most important concepts and methods on the basis of example. Previous and potential applications of asteroseismology are reviewed and future trends are attempted to be foreseen.Comment: 38 pages, 13 figures, to appear in: "Planets, Stars and Stellar Systems", eds. T. D. Oswalt et al., Springer Verla
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