1,112 research outputs found

    Immunosuppression and HCV recurrence after liver transplantation

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    SummaryHCV related liver disease is the most common indication for liver transplantation. Recurrence of HCV infection is universal and has a substantial impact on patient and graft survival. Immunosuppression is a major factor responsible for the accelerated recurrence and compressed natural history of recurrent HCV infection. Accumulating experience has provided data to support certain strategies for immunosuppressive regimens.From the available evidence, more severe recurrence results from repeated bolus corticosteroid therapy and anti-lymphocyte antibodies used to treat rejection. Low dose and slow tapering of steroids are better than high dose maintenance and/or rapid tapering. Recent meta-analyses favour steroid-free regimens but these are complicated to interpret as the absence of steroids may simply represent less immunopotency.There is no difference in HCV recurrence between tacrolimus and cyclosporine regimens, but tacrolimus increases graft and patient survival in HCV transplanted patients. There may be a beneficial effect of maintenance azathioprine given for 6months or longer. There is no conclusive evidence for benefit of mycophenolate and interleukin-2 receptor blockers. Few data are available for mTOR inhibitors. Better evidence is needed to establish the optimal immunosuppressive regimen for HCV recipients and more randomized trials should be performed

    Recombinants between Deformed wing virus and Varroa destructor virus-1 may prevail in Varroa destructor-infested honeybee colonies

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    We have used high-throughput Illumina sequencing to identify novel recombinants between deformed wing virus (DWV) and Varroa destructor virus-1 (VDV-1), which accumulate to higher levels than DWV in both honeybees and Varroa destructor mites. The recombinants, VDV-1VVD and VDV-1DVD, exhibit crossovers between the 5’-untranslated region (5’-UTR), and/or the regions encoding the structural (capsid) and non-structural viral proteins. This implies the genomes are modular and that each region may evolve independently, as demonstrated in human enteroviruses. Individual honeybee pupae were infected with a mixture of observed recombinants and DWV. The strong correlation between VDV-1DVD levels in honeybee pupae and the associated mites was observed, suggesting that this recombinant, with a DWV-derived 5’-UTR and non-structural protein region flanking VDV- 1-derived capsid encoding region, is better adapted to transmission between V. destructor and honeybees than the parental DWV or a recombinant bearing the VDV-1-derived 5’-UTR (VDV-1VVD)

    Characteristic Relations for Quantum Matrices

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    General algebraic properties of the algebras of vector fields over quantum linear groups GLq(N)GL_q(N) and SLq(N)SL_q(N) are studied. These quantum algebras appears to be quite similar to the classical matrix algebra. In particular, quantum analogues of the characteristic polynomial and characteristic identity are obtained for them. The qq-analogues of the Newton relations connecting two different generating sets of central elements of these algebras (the determinant-like and the trace-like ones) are derived. This allows one to express the qq-determinant of quantized vector fields in terms of their qq-traces.Comment: 11 pages, latex, an important reference [16] added

    Use Of Metal Bellows Noncontacting Seal And Guidelines For Steam Applications.

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    LecturePg. 21-28Steam turbines are used throughout the process industries and provide a reliable means of driving pumps, compressors; and other rotating equipment. Carbon rings are currently the most common way . of seali g these turbines. Although simple in design, the sealmg capability of these devices is very low. This results in high steam losses, lower efficiency, and decreased equipment reliability. This paper discusses the design and testing of a new noncontacting seal for operation in steam turbines. This seal was desi ned to improve turbine efficiency �and equipment reliability. Details from three field applications are discussed. Guidelines for installation and operation of steam turbine seals are also discussed, based on experience in the laboratory and field applications

    Combinatorial Hopf algebras and Towers of Algebras

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    Bergeron and Li have introduced a set of axioms which guarantee that the Grothendieck groups of a tower of algebras n0An\bigoplus_{n\ge0}A_n can be endowed with the structure of graded dual Hopf algebras. Hivert and Nzeutzhap, and independently Lam and Shimozono constructed dual graded graphs from primitive elements in Hopf algebras. In this paper we apply the composition of these constructions to towers of algebras. We show that if a tower n0An\bigoplus_{n\ge0}A_n gives rise to graded dual Hopf algebras then we must have dim(An)=rnn!\dim(A_n)=r^nn! where r=dim(A1)r = \dim(A_1).Comment: 7 page

    Fermionic Coset, Critical Level W^(2)_4-Algebra and Higher Spins

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    The fermionic coset is a limit of the pure spinor formulation of the AdS5xS5 sigma model as well as a limit of a nonlinear topological A-model, introduced by Berkovits. We study the latter, especially its symmetries, and map them to higher spin algebras. We show the following. The linear A-model possesses affine \AKMSA{pgl}{4}{4}_0 symmetry at critical level and its \AKMSA{psl}{4}{4}_0 current-current perturbation is the nonlinear model. We find that the perturbation preserves W4(2)\mathcal{W}^{(2)}_4-algebra symmetry at critical level. There is a topological algebra associated to \AKMSA{pgl}{4}{4}_0 with the properties that the perturbation is BRST-exact. Further, the BRST-cohomology contains world-sheet supersymmetric symplectic fermions and the non-trivial generators of the W4(2)\mathcal{W}^{(2)}_4-algebra. The Zhu functor maps the linear model to a higher spin theory. We analyze its \SLSA{psl}{4}{4} action and find finite dimensional short multiplets.Comment: 25 page

    Effects of donor/recipient human leukocyte antigen mismatch on human cytomegalovirus replication following liver transplantation.

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    Background Natural immunity against cytomegalovirus (CMV) can control virus replication after solid organ transplantation; however, it is not known which components of the adaptive immune system mediate this protection. We investigated whether this protection requires human leukocyte antigen (HLA) matching between donor and recipient by exploiting the fact that, unlike transplantation of other solid organs, liver transplantation does not require HLA matching, but some donor and recipient pairs may nevertheless be matched by chance. Methods To further investigate this immune control, we determined whether chance HLA matching between donor (D) and recipient (R) in liver transplants affected a range of viral replication parameters. Results In total, 274 liver transplant recipients were stratified according to matches at the HLA A, HLA B, and HLA DR loci. The incidence of CMV viremia, kinetics of replication, and peak viral load were similar between the HLA matched and mismatched patients in the D+/R+ and D−/R+ transplant groups. D+/R− transplants with 1 or 2 mismatches at the HLA DR locus had a higher incidence of CMV viremia >3000 genomes/mL blood compared to patients matched at this locus (78% vs. 17%; P = 0.01). Evidence was seen that matching at the HLA A locus had a small effect on peak viral loads in D+/R− patients, with median peak loads of 3540 and 14,706 genomes/mL in the 0 and combined (1 and 2) mismatch groups, respectively (P = 0.03). Conclusion Overall, our data indicate that, in the setting of liver transplantation, prevention of CMV infection and control of CMV replication by adaptive immunity is minimally influenced by HLA matching of the donor and recipient. Our data raise questions about immune control of CMV in the liver and also about the cells in which the virus is amplified to give rise to CMV viremia

    q-Analogue of Am1An1Amn1A_{m-1}\oplus A_{n-1}\subset A_{mn-1}

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    A natural embedding Am1An1Amn1A_{m-1}\oplus A_{n-1}\subset A_{mn-1} for the corresponding quantum algebras is constructed through the appropriate comultiplication on the generators of each of the Am1A_{m-1} and An1A_{n-1} algebras. The above embedding is proved in their qq-boson realization by means of the isomorphism between the Aq\mathcal{A}_q^{-} (mn)nAq\sim {\otimes} ^n \mathcal{A}_q^{-}(m)mAq\sim {\otimes}^m\mathcal{A}_q^{-}(n) algebras.Comment: 11 pages, no figures. In memory of professor R. P. Rousse

    Role of 1q21 in multiple myeloma: From pathogenesis to possible therapeutic targets

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    Multiple myeloma (MM) is characterized by an accumulation of malignant plasma cells (PCs) in the bone marrow (BM). The amplification of 1q21 is one of the most common cytogenetic abnormalities occurring in around 40% of de novo patients and 70% of relapsed/refractory MM. Patients with this unfavorable cytogenetic abnormality are considered to be high risk with a poor response to standard therapies. The gene(s) driving amplification of the 1q21 amplicon has not been fully studied. A number of clear candidates are under investigation, and some of them (IL6R, ILF2, MCL-1, CKS1B and BCL9) have been recently proposed to be potential drivers of this region. However, much remains to be learned about the biology of the genes driving the disease progression in MM patients with 1q21 amp. Understanding the mechanisms of these genes is important for the development of effective targeted therapeutic approaches to treat these patients for whom effective therapies are currently lacking. In this paper, we review the current knowledge about the pathological features, the mechanism of 1q21 amplification, and the signal pathway of the most relevant candidate genes that have been suggested as possible therapeutic targets for the 1q21 amplicon
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