279 research outputs found

    Constructing Dirac linear fermions in terms of non-linear Heisenberg spinors

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    We show that the massive (or massless) neutrinos can be described as special states of Heisenberg nonlinear spinors. As a by-product of this decomposition a particularly attractive consequence appears: the possibility of relating the existence of only three species of mass-less neutrinos to such internal non-linear structure. At the same time it allows the possibility that neutrino oscillation can occurs even for massless neutrinos

    Mechanical Strength of 17 134 Model Proteins and Cysteine Slipknots

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    A new theoretical survey of proteins' resistance to constant speed stretching is performed for a set of 17 134 proteins as described by a structure-based model. The proteins selected have no gaps in their structure determination and consist of no more than 250 amino acids. Our previous studies have dealt with 7510 proteins of no more than 150 amino acids. The proteins are ranked according to the strength of the resistance. Most of the predicted top-strength proteins have not yet been studied experimentally. Architectures and folds which are likely to yield large forces are identified. New types of potent force clamps are discovered. They involve disulphide bridges and, in particular, cysteine slipknots. An effective energy parameter of the model is estimated by comparing the theoretical data on characteristic forces to the corresponding experimental values combined with an extrapolation of the theoretical data to the experimental pulling speeds. These studies provide guidance for future experiments on single molecule manipulation and should lead to selection of proteins for applications. A new class of proteins, involving cystein slipknots, is identified as one that is expected to lead to the strongest force clamps known. This class is characterized through molecular dynamics simulations.Comment: 40 pages, 13 PostScript figure

    What if cancer survival in Britain were the same as in Europe: how many deaths are avoidable?

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    OBJECTIVE: To estimate the number of deaths among cancer patients diagnosed in Great Britain that would be avoidable within 5 years of diagnosis if the mean (or highest) survival in Europe for patients diagnosed during 1985-1989, 1990-1994 and 1995-1999 were achieved. DESIGN: Five-year relative survival for cancers in Great Britain compared with that from other countries in the EUROCARE-2, -3 and -4 studies. Calculation of excess deaths (those more than expected from mortality in the general population) that would be avoidable among cancer patients in Britain if relative survival were the same as in Europe. SETTING: Great Britain (England, Wales, Scotland) and 13 other European countries. SUBJECTS: 2.8 million adults diagnosed in Britain with 1 of 39 cancers during 1985-1989 (followed up to 1994), 1990-1994 (followed up to 1999) and 1995-1999 (followed up to 2003). MAIN OUTCOME MEASURE: Annual number of avoidable deaths within 5 years of diagnosis. Percentage of the excess (cancer-related) deaths among cancer patients that would be avoidable. RESULTS: Compared with the mean European 5-year relative survival, the largest numbers of avoidable deaths for patients diagnosed during 1985-1989 were for cancers of the breast (about 18% of the excess mortality from this cancer, 7541 deaths), prostate (14%, 4285), colon (9%, 4090), stomach (8%, 3483) and lung (2%, 3548). For 1990-1994, the largest numbers of avoidable deaths were for cancers of the prostate (20%, 7335), breast (15%, 6165), colon (9%, 4376), stomach (9%, 3672), lung (2%, 3735) and kidney (22%, 2644). For 1995-1999, most of the avoidable deaths were for cancers of the prostate (17%, 5758), breast (15%, 5475), lung (3%, 4923), colon (10%, 4295), stomach (9%, 3137) and kidney (21%, 2686).Overall, some 6600-7500 premature deaths would have been avoided each year among cancer patients diagnosed in Britain during 1985-1999 if the mean survival in Europe had been achieved. This represents 6-7% of cancer-related mortality. Compared with the highest European survival, avoidable premature mortality among cancer patients fell from about 12 800 deaths a year (12.2% of cancer-related mortality) to about 11 400 deaths a year (10.6%) over the same period.A large component of the avoidable mortality is due to prostate cancer: excluding this cancer from comparison with the European mean survival reduces the annual number of avoidable deaths by 1000-1500, and the percentage of excess mortality by up to 1%. Compared with the highest survival, the annual number of avoidable deaths would be 1500-2000 fewer, and 1-2% lower as a percentage of excess mortality, but the overall trend in avoidable premature mortality among cancer patients would be similar, falling from 11.4% (1985-1989) to 10.3% (1990-1994) and 9.7% for those diagnosed during 1995-1999.For several cancers, survival in Britain was slightly higher than the mean survival in Europe; this represented some 110-180 premature deaths avoided each year during the period 1985-2003. CONCLUSIONS: Avoidable premature mortality among cancer patients diagnosed in Britain during 1985-1999 has represented 6-7% of cancer-related mortality compared with the mean survival in Europe. Compared with the highest levels of survival in Europe, the reduction from 12.2% to 10.6% of cancer-related mortality reflects small but steady progress over the period 1985-2003

    The role of tumour-derived iNOS in tumour progression and angiogenesis

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    BACKGROUND: Progressive tumour growth is dependent on the development of a functional tumour vasculature and highly regulated by growth factors and cytokines. Nitric oxide (NO) is a free radical, produced both by tumour and host cells, and functions as a signalling molecule downstream of several angiogenic factors. Both pro-and antitumourigenic properties have been attributed to NO. METHODS: The expression of the inducible isoform of NO synthase (iNOS) was knocked down in the C6 glioma cell line using constitutive expression of antisense RNA, and the effect of tumour-derived NO on tumour progression and angiogenesis was investigated. RESULTS: Tumours in which iNOS expression was decreased displayed significantly reduced growth rates compared with tumours derived from parental C6 cells. Quantitative non-invasive magnetic resonance imaging and fluorescence microscopy of tumour uptake of Hoechst 33342, and haematoxylin and eosin staining, revealed significantly impaired vascular development and function in antisense iNOS tumours compared with control in vivo, primarily associated with the more necrotic tumour core. Decreased iNOS expression had no effect on tumour VEGF expression. CONCLUSION: Nitric oxide derived from tumour iNOS is an important modulator of tumour progression and angiogenesis in C6 gliomas and further supports the therapeutic strategy of inhibiting iNOS for the treatment of cancer. British Journal of Cancer (2011) 104, 83-90. doi:10.1038/sj.bjc.6606034 www.bjcancer.com Published online 7 December 2010 (C) 2011 Cancer Research U

    ChemR23 Dampens Lung Inflammation and Enhances Anti-viral Immunity in a Mouse Model of Acute Viral Pneumonia

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    Viral diseases of the respiratory tract, which include influenza pandemic, children acute bronchiolitis, and viral pneumonia of the elderly, represent major health problems. Plasmacytoid dendritic cells play an important role in anti-viral immunity, and these cells were recently shown to express ChemR23, the receptor for the chemoattractant protein chemerin, which is expressed by epithelial cells in the lung. Our aim was to determine the role played by the chemerin/ChemR23 system in the physiopathology of viral pneumonia, using the pneumonia virus of mice (PVM) as a model. Wild-type and ChemR23 knock-out mice were infected by PVM and followed for functional and inflammatory parameters. ChemR23−/− mice displayed higher mortality/morbidity, alteration of lung function, delayed viral clearance and increased neutrophilic infiltration. We demonstrated in these mice a lower recruitment of plasmacytoid dendritic cells and a reduction in type I interferon production. The role of plasmacytoid dendritic cells was further addressed by performing depletion and adoptive transfer experiments as well as by the generation of chimeric mice, demonstrating two opposite effects of the chemerin/ChemR23 system. First, the ChemR23-dependent recruitment of plasmacytoid dendritic cells contributes to adaptive immune responses and viral clearance, but also enhances the inflammatory response. Second, increased morbidity/mortality in ChemR23−/− mice is not due to defective plasmacytoid dendritic cells recruitment, but rather to the loss of an anti-inflammatory pathway involving ChemR23 expressed by non-leukocytic cells. The chemerin/ChemR23 system plays important roles in the physiopathology of viral pneumonia, and might therefore be considered as a therapeutic target for anti-viral and anti-inflammatory therapies

    Exploiting antitumor immunity to overcome relapse and improve remission duration

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    Cancer survivors often relapse due to evolving drug-resistant clones and repopulating tumor stem cells. Our preclinical study demonstrated that terminal cancer patient’s lymphocytes can be converted from tolerant bystanders in vivo into effective cytotoxic T-lymphocytes in vitro killing patient’s own tumor cells containing drug-resistant clones and tumor stem cells. We designed a clinical trial combining peginterferon α-2b with imatinib for treatment of stage III/IV gastrointestinal stromal tumor (GIST) with the rational that peginterferon α-2b serves as danger signals to promote antitumor immunity while imatinib’s effective tumor killing undermines tumor-induced tolerance and supply tumor-specific antigens in vivo without leukopenia, thus allowing for proper dendritic cell and cytotoxic T-lymphocyte differentiation toward Th1 response. Interim analysis of eight patients demonstrated significant induction of IFN-γ-producing-CD8+, -CD4+, -NK cell, and IFN-γ-producing-tumor-infiltrating-lymphocytes, signifying significant Th1 response and NK cell activation. After a median follow-up of 3.6 years, complete response (CR) + partial response (PR) = 100%, overall survival = 100%, one patient died of unrelated illness while in remission, six of seven evaluable patients are either in continuing PR/CR (5 patients) or have progression-free survival (PFS, 1 patient) exceeding the upper limit of the 95% confidence level of the genotype-specific-PFS of the phase III imatinib-monotherapy (CALGB150105/SWOGS0033), demonstrating highly promising clinical outcomes. The current trial is closed in preparation for a larger future trial. We conclude that combination of targeted therapy and immunotherapy is safe and induced significant Th1 response and NK cell activation and demonstrated highly promising clinical efficacy in GIST, thus warranting development in other tumor types

    Contemporary management of cancer of the oral cavity

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    Oral cancer represents a common entity comprising a third of all head and neck malignant tumors. The options for curative treatment of oral cavity cancer have not changed significantly in the last three decades; however, the work up, the approach to surveillance, and the options for reconstruction have evolved significantly. Because of the profound functional and cosmetic importance of the oral cavity, management of oral cavity cancers requires a thorough understanding of disease progression, approaches to management and options for reconstruction. The purpose of this review is to discuss the most current management options for oral cavity cancers

    Pan-cancer analysis of whole genomes

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    Cancer is driven by genetic change, and the advent of massively parallel sequencing has enabled systematic documentation of this variation at the whole-genome scale(1-3). Here we report the integrative analysis of 2,658 whole-cancer genomes and their matching normal tissues across 38 tumour types from the Pan-Cancer Analysis of Whole Genomes (PCAWG) Consortium of the International Cancer Genome Consortium (ICGC) and The Cancer Genome Atlas (TCGA). We describe the generation of the PCAWG resource, facilitated by international data sharing using compute clouds. On average, cancer genomes contained 4-5 driver mutations when combining coding and non-coding genomic elements; however, in around 5% of cases no drivers were identified, suggesting that cancer driver discovery is not yet complete. Chromothripsis, in which many clustered structural variants arise in a single catastrophic event, is frequently an early event in tumour evolution; in acral melanoma, for example, these events precede most somatic point mutations and affect several cancer-associated genes simultaneously. Cancers with abnormal telomere maintenance often originate from tissues with low replicative activity and show several mechanisms of preventing telomere attrition to critical levels. Common and rare germline variants affect patterns of somatic mutation, including point mutations, structural variants and somatic retrotransposition. A collection of papers from the PCAWG Consortium describes non-coding mutations that drive cancer beyond those in the TERT promoter(4); identifies new signatures of mutational processes that cause base substitutions, small insertions and deletions and structural variation(5,6); analyses timings and patterns of tumour evolution(7); describes the diverse transcriptional consequences of somatic mutation on splicing, expression levels, fusion genes and promoter activity(8,9); and evaluates a range of more-specialized features of cancer genomes(8,10-18).Peer reviewe

    Corrigendum to "Search for flavour-changing neutral-current couplings between the top quark and the photon with the ATLAS detector at √s=13 TeV" (Physics Letters B, 842 (2023), 137379)

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    Gravitational Lensing from a Spacetime Perspective

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