173 research outputs found
Finite flavour groups of fermions
We present an overview of the theory of finite groups, with regard to their
application as flavour symmetries in particle physics. In a general part, we
discuss useful theorems concerning group structure, conjugacy classes,
representations and character tables. In a specialized part, we attempt to give
a fairly comprehensive review of finite subgroups of SO(3) and SU(3), in which
we apply and illustrate the general theory. Moreover, we also provide a concise
description of the symmetric and alternating groups and comment on the
relationship between finite subgroups of U(3) and finite subgroups of SU(3).
Though in this review we give a detailed description of a wide range of finite
groups, the main focus is on the methods which allow the exploration of their
different aspects.Comment: 89 pages, 6 figures, some references added, rearrangement of part of
the material, section on SU(3) subgroups substantially extended, some minor
revisions. Version for publication in J. Phys. A. Table 12 corrected to match
eq.(256), table 14 and eq.(314) corrected to match the 2-dimensional irreps
defined on p.6
Remote magnetic versus manual catheters: evaluation of ablation effect in atrial fibrillation by myocardial marker levels
Background A remote magnetic navigation (MN) system is available for radiofrequency ablation of atrial fibrillation (AF), challenging the conventional manual ablation technique. The myocardial markers were measured to compare the effects of the two types of MN catheters with those of a manual-irrigated catheter in AF ablation. Methods AF patients underwent an ablation procedure using either a conventional manual-irrigated catheter (CIR, n=65) or an MN system utilizing either an irrigated (RMI, n=23) or non-irrigated catheter (RMN, n=26). Levels of troponin T (TnT) and the cardiac isoform of creatin kinase (CKMB) were measured before and after ablation. Results Mean procedure times and total ablation times were longer employing the remote magnetic system. In all groups, there were pronounced increases in markers of myocardial injury after ablation, demonstrating a significant correlation between total ablation time and post-ablation levels of TnT and CKMB (CIR r=0.61 and 0.53, p<0.001; RMI r=0.74 and 0.73, p<0.001; and RMN r=0.51 and 0.59, p<0.01). Time-corrected release of TnT was significantly higher in the CIR group than in the other groups. Of the patients, 59.6% were free from AF at follow-up (12.2± 5.4 months) and there were no differences in success rate between the three groups. Conclusions Remote magnetic catheters may create more discrete and predictable ablation lesions measured by myocardial enzymes and may require longer total ablation time to reach the procedural endpoints. Remote magnetic non-irrigated catheters do not appear to be inferior to magnetic irrigated catheters in terms of myocardial enzyme release and clinical outcome
Mayo Clinic consensus report on membranous nephropathy: proposal for a novel classification
Membranous nephropathy (MN) is a pattern of injury caused by autoantibodies binding to specific target antigens, with accumulation of immune complexes along the subepithelial region of glomerular basement membranes. The past 20 years have brought revolutionary advances in the understanding of MN, particularly via the discovery of novel target antigens and their respective autoantibodies. These discoveries have challenged the traditional classification of MN into primary and secondary forms. At least 14 target antigens have been identified, accounting for 80%-90% of cases of MN. Many of the forms of MN associated with these novel MN target antigens have distinctive clinical and pathologic phenotypes. The Mayo Clinic consensus report on MN proposes a 2-step classification of MN. The first step, when possible, is identification of the target antigen, based on a multistep algorithm and using a combination of serology, staining of the kidney biopsy tissue by immunofluorescence or immunohistochemistry, and/or mass spectrometry methodology. The second step is the search for a potential underlying disease or associated condition, which is particularly relevant when knowledge of the target antigen is available to direct it. The meeting acknowledges that the resources and equipment required to perform the proposed testing may not be generally available. However, the meeting consensus was that the time has come to adopt an antigen-based classification of MN because this approach will allow for accurate and specific MN diagnosis, with significant implications for patient management and targeted treatment
The Relative Influence of Competition and Prey Defenses on the Phenotypic Structure of Insectivorous Bat Ensembles in Southern Africa
Deterministic filters such as competition and prey defences should have a strong influence on the community structure of animals such as insectivorous bats that have life histories characterized by low fecundity, low predation risk, long life expectancy, and stable populations. We investigated the relative influence of these two deterministic filters on the phenotypic structure of insectivorous bat ensembles in southern Africa. We used null models to simulate the random phenotypic patterns expected in the absence of competition or prey defences and analysed the deviations of the observed phenotypic pattern from these expected random patterns. The phenotypic structure at local scales exhibited non-random patterns consistent with both competition and prey defense hypotheses. There was evidence that competition influenced body size distribution across ensembles. Competition also influenced wing and echolocation patterns in ensembles and in functional foraging groups with high species richness or abundance. At the same time, prey defense filters influenced echolocation patterns in two species-poor ensembles. Non-random patterns remained evident even after we removed the influence of body size from wing morphology and echolocation parameters taking phylogeny into account. However, abiotic filters such as geographic distribution ranges of small and large-bodied species, extinction risk, and the physics of flight and sound probably also interacted with biotic filters at local and/or regional scales to influence the community structure of sympatric bats in southern Africa. Future studies should investigate alternative parameters that define bat community structure such as diet and abundance to better determine the influence of competition and prey defences on the structure of insectivorous bat ensembles in southern Africa
Therapeutic targeting of cathepsin C::from pathophysiology to treatment
Cathepsin C (CatC) is a highly conserved tetrameric lysosomal cysteine dipeptidyl aminopeptidase. The best characterized physiological function of CatC is the activation of pro-inflammatory granule-associated serine proteases. These proteases are synthesized as inactive zymogens containing an N-terminal pro-dipeptide, which maintains the zymogen in its inactive conformation and prevents premature activation, which is potentially toxic to the cell. The activation of serine protease zymogens occurs through cleavage of the N-terminal dipeptide by CatC during cell maturation in the bone marrow. In vivo data suggest that pharmacological inhibition of pro-inflammatory serine proteases would suppress or attenuate deleterious effects of inflammatory/auto-immune disorders mediated by these proteases. The pathological deficiency in CatC is associated with Papillon-Lefèvre syndrome. The patients however do not present marked immunodeficiency despite the absence of active serine proteases in immune defense cells. Hence, the transitory pharmacological blockade of CatC activity in the precursor cells of the bone marrow may represent an attractive therapeutic strategy to regulate activity of serine proteases in inflammatory and immunologic conditions. A variety of CatC inhibitors have been developed both by pharmaceutical companies and academic investigators, some of which are currently being employed and evaluated in preclinical/clinical trials
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