186 research outputs found

    Adding Value to Grasslands Through Certified Organic Beef Production

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    New demands are being made for safe beef from low input production systems (low input of energy, pesticides, other chemically synthesised products and hormones and GM free) by the main retailers and consumers (Howard, 2004). These present an opportunity for adding value to grazing production systems and to reinforce relationships among farmers, agro-industrialists, exporters and consumers and to show advantages of positive externalities of grasslands (Meister, 2001)

    Finite-temperature relativistic Landau problem and the relativistic quantum Hall effect

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    This paper presents a study of the free energy and particle density of the relativistic Landau problem, and their relevance to the quantum Hall effect. We study first the zero temperature Casimir energy and fermion number for Dirac fields in a 2+1-dimensional Minkowski space-time, in the presence of a uniform magnetic field perpendicular to the spatial manifold. Then, we go to the finite-temperature problem, with a chemical potential, introduced as a uniform zero component of the gauge potential. By performing a Lorentz boost, we obtain Hall's conductivity in the case of crossed electric and magnetic fields.Comment: Final version, to appear in Journal of Physics A: Mathematical and Genera

    Closure of an iatrogenic tracheo-esophageal fistula with bronchoscopic gluing in a mechanically ventilated adult patient

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    Management of acquired nonmalignant tracheo-esophageal fistula (TEF) in mechanically ventilated patients is controversial. Surgical correction is often contraindicated because the high operative risk and spontaneous closure is unlikely due to the positive pressure ventilation. We present a case of successful closure of an iatrogenic TEF in a mechanically ventilated patient with bronchoscopic application of fibrin glue. The technique may be proposed in high-risk patients as either an alternative to surgery or as a first-line attempt before surgical correction

    Bronze and Iron Age salt production on the Italian Tyrrhenian coast:An overview

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    A synthesis of the current knowledge of the so-called Italian giacimenti a olle d’impasto rossiccio (reddish jar potsherd deposits) is presented. These sites are common along the Tyrrhenian side of Central Italy and are usually interpreted as salt-production sites, because of parallels with similar European specialised sites. In the latter, salt was obtained by boiling a brine in special disposable pottery, a technique known as briquetage. However, the analogies are not straightforward and alternative hypotheses, e.g. fish-processing, and a more complex intertwined economy have also been put forward. To solve the interpretation issues, we advocate to use a multidisciplinary approach involving quantification of the ceramics encountered, establishment of their morphological and functional typologies, and physico/chemical analyses to identify their use

    A hepatitis C avidity test for determining recent and past infections in both plasma and dried blood spots

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    DBS testing has been used successfully to detect HCV antibody positive individuals. Determining how long someone has been infected is important for surveillance initiatives. Antibody avidity is a method that can be used to calculate recency of infection. A HCV avidity assay was evaluated for both plasma and DBS. Study design: To measure antibody avidity a commercial HCV ELISA was modified using 7 M urea. The plasma samples were split into: group 1 (recently infected N = 19), group 2 (chronic carrier N = 300) and group 3 (resolved infection N = 82). Mock DBS made from group 1 (N = 12), group 2 (N = 50), group 3 (N = 25) and two seroconverter panels were evaluated. 133 DBS taken from patients known to have a resolved infection or be a chronic carrier were also tested. The avidity assay cut-off was set at AI ≀ 30 for a recent infection. Using sequential samples the assay could detect a recent infection in the first 4–5 months from the point of infection. Most of the false positive results (AI < 30 among cases known not to have had recent infection) were detected among known resolved infections, in both the plasma and DBS; as a result, a testing algorithm has been designed incorporating both PCR and two dilution factors. The sensitivity and specificity of the assay on plasma was 100% and 99.3%, respectively, while DBS had 100% sensitivity and 98.3% specificity. The HCV avidity assay can be used to distinguish between chronic and recent infection using either plasma or DBS as the sample type

    The Intracellular DNA Sensor IFI16 Gene Acts as Restriction Factor for Human Cytomegalovirus Replication

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    Human interferon (IFN)-inducible IFI16 protein, an innate immune sensor of intracellular DNA, modulates various cell functions, however, its role in regulating virus growth remains unresolved. Here, we adopt two approaches to investigate whether IFI16 exerts pro- and/or anti-viral actions. First, the IFI16 gene was silenced using specific small interfering RNAs (siRNA) in human embryo lung fibroblasts (HELF) and replication of DNA and RNA viruses evaluated. IFI16-knockdown resulted in enhanced replication of Herpesviruses, in particular, Human Cytomegalovirus (HCMV). Consistent with this, HELF transduction with a dominant negative form of IFI16 lacking the PYRIN domain (PYD) enhanced the replication of HCMV. Second, HCMV replication was compared between HELFs overexpressing either the IFI16 gene or the LacZ gene. IFI16 overexpression decreased both virus yield and viral DNA copy number. Early and late, but not immediate-early, mRNAs and proteins were strongly down-regulated, thus IFI16 may exert its antiviral effect by impairing viral DNA synthesis. Constructs with the luciferase reporter gene driven by deleted or site-specific mutated forms of the HCMV DNA polymerase (UL54) promoter demonstrated that the inverted repeat element 1 (IR-1), located between βˆ’54 and βˆ’43 relative to the transcription start site, is the target of IFI16 suppression. Indeed, electrophoretic mobility shift assays and chromatin immunoprecipitation demonstrated that suppression of the UL54 promoter is mediated by IFI16-induced blocking of Sp1-like factors. Consistent with these results, deletion of the putative Sp1 responsive element from the HCMV UL44 promoter also relieved IFI16 suppression. Together, these data implicate IFI16 as a novel restriction factor against HCMV replication and provide new insight into the physiological functions of the IFN-inducible gene IFI16 as a viral restriction factor

    Sequential mutations associated with adaptation of human cytomegalovirus to growth in cell culture

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    Mutations that occurred during adaptation of human cytomegalovirus to cell culture were monitored by isolating four strains from clinical samples, passaging them in various cell types and sequencing ten complete virus genomes from the final passages. Mutational dynamics were assessed by targeted sequencing of intermediate passages and the original clinical samples. Gene RL13 and the UL128 locus (UL128L, consisting of genes UL128, UL130 and UL131A) mutated in all strains. Mutations in RL13 occurred in fibroblast, epithelial and endothelial cells, whereas those in UL128L were limited to fibroblasts and detected later than those in RL13. In addition, a region containing genes UL145, UL144, UL142, UL141 and UL140 mutated in three strains. All strains exhibited numerous mutations in other regions of the genome, with a preponderance in parts of the inverted repeats. An investigation was carried out on the kinetic growth yields of viruses derived from selected passages that were predominantly non-mutated in RL13 and UL128L (RL13+UL128L+), or that were largely mutated in RL13 (RL13βˆ’UL128L+) or both RL13 and UL128L (RL13βˆ’UL128Lβˆ’). RL13βˆ’UL128Lβˆ’ viruses produced greater yields of infectious progeny than RL13βˆ’UL128L+ viruses, and RL13βˆ’UL128L+ viruses produced greater yields than RL13+UL128L+ viruses. These results suggest strongly that RL13 and UL128L exert at least partially independent suppressive effects on growth in fibroblasts. As all isolates proved genetically unstable in all cell types tested, caution is advised in choosing and monitoring strains for experimental studies of vulnerable functions, particularly those involved in cell tropism, immune evasion or growth temperance

    Detection of a Single Identical Cytomegalovirus (CMV) Strain in Recently Seroconverted Young Women

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    Infection with multiple CMV strains is common in immunocompromised hosts, but its occurrence in normal hosts has not been well-studied.We analyzed CMV strains longitudinally in women who acquired CMV while enrolled in a CMV glycoprotein B (gB) vaccine trial. Sequencing of four variable genes was performed in samples collected from seroconversion and up to 34 months thereafter.199 cultured isolates from 53 women and 65 original fluids from a subset of 19 women were sequenced. 51 women were infected with one strain each without evidence for genetic drift; only two women shed multiple strains. Genetic variability among strains increased with the number of sequenced genetic loci. Nevertheless, 13 of 53 women proved to be infected with an identical CMV strain based on sequencing at all four variable genes. CMV vaccine did not alter the degree of genetic diversity amongst strains.Primary CMV infection in healthy women nearly always involves shedding of one strain that remains stable over time. Immunization with CMVgB-1 vaccine strain is not selective against specific strains. Although 75% of women harbored their unique strain, or a strain shared with only one other woman, 25% shared a single common strain, suggesting that this predominant strain with a particular combination of genetic loci is advantageous in this large urban area
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