1,032 research outputs found

    Two-Dimensional Bosonization from Variable Shifts in the Path Integral

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    A method to perform bosonization of a fermionic theory in (1+1) dimensions in a path integral framework is developed. The method relies exclusively on the path integral property of allowing variable shifts, and does not depend on the explicit form of Greens functions. Two examples, the Schwinger model and the massless Thirring model, are worked out.Comment: 4 page

    Radiative corrections to the Casimir energy and effective field theory

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    We discuss radiative corrections to the Casimir effect from an effective field theory point of view. It is an improvement and more complete version of a previous discussion by Kong and Ravndal. By writing down the most general effective Lagrangian respecting the symmetries and the boundary conditions, we are able to reproduce earlier results of Bordag, Robaschik and Wieczorek calculated in full QED. They obtained the correction E_0^(1) = \pi^2\alpha/2560mL^4 to the Casimir energy. We find that this leading correction is due to surface terms in the effective theory, which we attribute to having dominant fluctuations localized on the plates.Comment: 11 pages, revised version, Sec. 2 is rewritte

    A common missense variant in BRCA2 predisposes to early onset breast cancer

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    INTRODUCTION: Mutations in the BRCA2 gene are one of the two major causes of hereditary breast cancer. Protein-truncating mutations of BRCA2 are usually deleterious and increase the risk of breast cancer up to 80% over a lifetime. A few missense mutations in BRCA2 are believed to have a similarly high penetrance, apart from more common neutral polymorphisms. It is often difficult to classify a particular sequence variant as a mutation or a polymorphism. For a deleterious variant, one would expect a greater allele frequency in breast cancer cases than in ethnic-matched controls. In contrast, neutral polymorphic variants should be equally frequent in the two groups. METHODS: We genotyped 3,241 cases of breast cancer diagnosed at under 51 years of age, unselected for family history, from 18 hospitals throughout Poland and 2,791 ethnic-matched controls for a single BRCA2 C5972T variant. RESULTS: The variant was present in approximately 6% of the Polish population. In the study, 13 women (11 cases and two controls (OR = 4.7; p = 0.02)) were homozygous for the variant allele. The overall odds ratio for breast cancer in women with a single copy of the BRCA2 C5972T variant was 1.1 (p = 0.7); however, the effect was significant for patients diagnosed at or before age 40 (OR = 1.4; p = 0.04). We reviewed the association between the BRCA2 variant in different histologic subgroups and found the effect most pronounced in women who had ductal carcinoma in situ (DCIS) with micro-invasion (OR = 2.8; p < 0.0001). CONCLUSION: The BRCA2 C5972T allele is a common variant in Poland that increases the risk of DCIS with micro-invasion. The homozygous state is rare but increases the risk of breast cancer five-fold

    Design and Creative Methods as a Practice of Liminality in Community-Academic Research Projects

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    This paper aims to explore the types of spaces and experiences that are created by design and creative practices. More specifically, it focuses on how design and creative practices can engender transformations in the mindset, knowledge, emotions and social relations of people who participate in such practices. To do this, the paper investigates the concepts of liminality and liminal spaces, and the relationships between design/creative methods and liminal spaces using insights from four case studies. The results reveal that design and creative practices may create liminal spaces in many ways, such as neutralizing the working environments, encouraging people to experiment with new ideas and helping them express themselves more freely

    Evaluation of polygenic risk scores for breast and ovarian cancer risk prediction in BRCA1 and BRCA2 mutation carriers

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    Background: Genome-wide association studies (GWAS) have identified 94 common single-nucleotide polymorphisms (SNPs) associated with breast cancer (BC) risk and 18 associated with ovarian cancer (OC) risk. Several of these are also associated with risk of BC or OC for women who carry a pathogenic mutation in the high-risk BC and OC genes BRCA1 or BRCA2. The combined effects of these variants on BC or OC risk for BRCA1 and BRCA2 mutation carriers have not yet been assessed while their clinical management could benefit from improved personalized risk estimates. Methods: We constructed polygenic risk scores (PRS) using BC and OC susceptibility SNPs identified through population-based GWAS: for BC (overall, estrogen receptor [ER]-positive, and ER-negative) and for OC. Using data from 15 252 female BRCA1 and 8211 BRCA2 carriers, the association of each PRS with BC or OC risk was evaluated using a weighted cohort approach, with time to diagnosis as the outcome and estimation of the hazard ratios (HRs) per standard deviation increase in the PRS. Results: The PRS for ER-negative BC displayed the strongest association with BC risk in BRCA1 carriers (HR = 1.27, 95% confidence interval [CI] = 1.23 to 1.31, P = 8.2 x 10(53)). In BRCA2 carriers, the strongest association with BC risk was seen for the overall BC PRS (HR = 1.22, 95% CI = 1.17 to 1.28, P = 7.2 x 10(-20)). The OC PRS was strongly associated with OC risk for both BRCA1 and BRCA2 carriers. These translate to differences in absolute risks (more than 10% in each case) between the top and bottom deciles of the PRS distribution; for example, the OC risk was 6% by age 80 years for BRCA2 carriers at the 10th percentile of the OC PRS compared with 19% risk for those at the 90th percentile of PRS. Conclusions: BC and OC PRS are predictive of cancer risk in BRCA1 and BRCA2 carriers. Incorporation of the PRS into risk prediction models has promise to better inform decisions on cancer risk management

    Significance of Toll-like Receptors Expression in Tumor Growth and Spreading: A Short Review

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    Toll-like receptors (TLRs) are considered now as crucial sensors of innate immunity. Their role in the recognition of pathogens and the initiation of adaptive immune responses against them is well known. However, in last years TLRs have been identified on several tumor cells, including human malignancies. Their expression in cancer was found to be twofold: either promoting or inhibiting tumor progression. It was also demonstrated that several TLRs agonists, either natural or synthetic ones, may have beneficial effect on tumor-mediated disease, leading to potentiation of immune response to tumor-associated antigens. TLR-agonist linked tumor immunotherapy is still in nascent state, but growing rapidly, also in the area of common human malignancies. To date, the most promising and the most frequently studied interaction in tumor immunotherapy trials seems to be TLR9 and its synthetic agonists
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