3,651 research outputs found

    Skeletal muscle as a regulator of the longevity protein, Klotho

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    Klotho is a powerful longevity protein that has been linked to the prevention of muscle atrophy, osteopenia, and cardiovascular disease. Similar anti-aging effects have also been ascribed to exercise and physical activity. While an association between muscle function and Klotho expression has been previously suggested from longitudinal cohort studies, a direct relationship between circulating Klotho and skeletal muscle has not been investigated. In this paper, we present a review of the literature and preliminary evidence that, together, suggests Klotho expression may be modulated by skeletal muscle activity. Our pilot clinical findings performed in young and aged individuals suggest that circulating Klotho levels are upregulated in response to an acute exercise bout, but that the response may be dependent on fitness level. A similar upregulation of circulating Klotho is also observed in response to an acute exercise in young and old mice, suggesting that this may be a good model for mechanistically probing the role of physical activity on Klotho expression. Finally, we highlight overlapping signaling pathways that are modulated by both Klotho and skeletal muscle and propose potential mechanisms for cross-talk between the two. It is hoped that this review will stimulate further consideration of the relationship between skeletal muscle activity and Klotho expression, potentially leading to important insights into the well-documented systemic anti-aging effects of exercise. © 2014 Avin, Coen, Huang, Stolz, Sowa, Dubé, Goodpaster, O'Doherty and Ambrosio

    Vortices in polariton OPO superfluids

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    This chapter reviews the occurrence of quantised vortices in polariton fluids, primarily when polaritons are driven in the optical parametric oscillator (OPO) regime. We first review the OPO physics, together with both its analytical and numerical modelling, the latter being necessary for the description of finite size systems. Pattern formation is typical in systems driven away from equilibrium. Similarly, we find that uniform OPO solutions can be unstable to the spontaneous formation of quantised vortices. However, metastable vortices can only be injected externally into an otherwise stable symmetric state, and their persistence is due to the OPO superfluid properties. We discuss how the currents charactering an OPO play a crucial role in the occurrence and dynamics of both metastable and spontaneous vortices.Comment: 40 pages, 16 figure

    Phase Structure and Compactness

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    In order to study the influence of compactness on low-energy properties, we compare the phase structures of the compact and non-compact two-dimensional multi-frequency sine-Gordon models. It is shown that the high-energy scaling of the compact and non-compact models coincides, but their low-energy behaviors differ. The critical frequency β2=8π\beta^2 = 8\pi at which the sine-Gordon model undergoes a topological phase transition is found to be unaffected by the compactness of the field since it is determined by high-energy scaling laws. However, the compact two-frequency sine-Gordon model has first and second order phase transitions determined by the low-energy scaling: we show that these are absent in the non-compact model.Comment: 21 pages, 5 figures, minor changes, final version, accepted for publication in JHE

    Confucian Principles: A Study of Chinese Americans’ Interpersonal Relationships in Selected Children’s Picturebooks

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    [[abstract]]There has not been enough critical analysis of children’s literature by and about Chinese Americans, especially when compared to other minority groups in the United States. In particular, Chinese American historical books lack extensive analysis. It is important to reflect cultural accuracy in literature and to help children develop clear concepts of self and others by providing precise cultural and physical characteristics of people. While cultural authenticity allows children the opportunity to see a reflection of real experiences within a book instead of seeing stereotypes or misrepresentations, obtaining correct information about a certain time period can help children to see images of immigration accurately represented in literature. Using the Confucian delineation of interpersonal relationships as the major criterion of cultural authenticity, this article examines three currently available children’s picturebooks set in the historical period between 1848 and 1885. In addition to exploring how Chinese Americans’ interpersonal relationships are portrayed in these children’s historical books, this article argues for more proactive inclusion of the diversity in selection of picturebooks.[[notice]]補正完

    Sine-Gordon Model - Renormalization Group Solutions and Applications

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    The sine-Gordon model is discussed and analyzed within the framework of the renormalization group theory. A perturbative renormalization group procedure is carried out through a decomposition of the sine-Gordon field in slow and fast modes. An effective slow modes's theory is derived and re-scaled to obtain the model's flow equations. The resulting Kosterlitz-Thouless phase diagram is obtained and discussed in detail. The theory's gap is estimated in terms of the sine-Gordon model paramaters. The mapping between the sine-Gordon model and models for interacting electrons in one dimension, such as the g-ology model and Hubbard model, is discussed and the previous renormalization group results, obtained for the sine-Gordon model, are thus borrowed to describe different aspects of Luttinger liquid systems, such as the nature of its excitations and phase transitions. The calculations are carried out in a thorough and pedagogical manner, aiming the reader with no previous experience with the sine-Gordon model or the renormalization group approach.Comment: 44 pages, 7 figure

    NLO QCD Corrections to BcB_c-to-Charmonium Form Factors

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    The Bc(1S0)B_c(^1S_0) meson to S-wave Charmonia transition form factors are calculated in next-to-leading order(NLO) accuracy of Quantum Chromodynamics(QCD). Our results indicate that the higher order corrections to these form factors are remarkable, and hence are important to the phenomenological study of the corresponding processes. For the convenience of comparison and use, the relevant expressions in asymptotic form at the limit of mc0m_c\rightarrow0 for the radiative corrections are presented

    Evolution of a supergene that regulates a trans-species social polymorphism

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    Supergenes are clusters of linked genetic loci that jointly affect the expression of complex phenotypes, such as social organization. Little is known about the origin and evolution of these intriguing genomic elements. Here we analyse whole-genome sequences of males from native populations of six fire ant species and show that variation in social organization is under the control of a novel supergene haplotype (termed Sb), which evolved by sequential incorporation of three inversions spanning half of a 'social chromosome'. Two of the inversions interrupt protein-coding genes, resulting in the increased expression of one gene and modest truncation in the primary protein structure of another. All six socially polymorphic species studied harbour the same three inversions, with the single origin of the supergene in their common ancestor inferred by phylogenomic analyses to have occurred half a million years ago. The persistence of Sb along with the ancestral SB haplotype through multiple speciation events provides a striking example of a functionally important trans-species social polymorphism presumably maintained by balancing selection. We found that while recombination between the Sb and SB haplotypes is severely restricted in all species, a low level of gene flux between the haplotypes has occurred following the appearance of the inversions, potentially mitigating the evolutionary degeneration expected at genomic regions that cannot freely recombine. These results provide a detailed picture of the structural genomic innovations involved in the formation of a supergene controlling a complex social phenotype

    Tumour-derived alkaline phosphatase regulates tumour growth, epithelial plasticity and disease-free survival in metastatic prostate cancer

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    BACKGROUND: Recent evidence suggests that bone-related parameters are the main prognostic factors for overall survival in advanced prostate cancer (PCa), with elevated circulating levels of alkaline phosphatase (ALP) thought to reflect the dysregulated bone formation accompanying distant metastases. We have identified that PCa cells express ALPL, the gene that encodes for tissue nonspecific ALP, and hypothesised that tumour-derived ALPL may contribute to disease progression. METHODS: Functional effects of ALPL inhibition were investigated in metastatic PCa cell lines. ALPL gene expression was analysed from published PCa data sets, and correlated with disease-free survival and metastasis. RESULTS: ALPL expression was increased in PCa cells from metastatic sites. A reduction in tumour-derived ALPL expression or ALP activity increased cell death, mesenchymal-to-epithelial transition and reduced migration. Alkaline phosphatase activity was decreased by the EMT repressor Snail. In men with PCa, tumour-derived ALPL correlated with EMT markers, and high ALPL expression was associated with a significant reduction in disease-free survival. CONCLUSIONS: Our studies reveal the function of tumour-derived ALPL in regulating cell death and epithelial plasticity, and demonstrate a strong association between ALPL expression in PCa cells and metastasis or disease-free survival, thus identifying tumour-derived ALPL as a major contributor to the pathogenesis of PCa progression.British Journal of Cancer advance online publication, 22 December 2016; doi:10.1038/bjc.2016.402 www.bjcancer.com

    The Bulk Channel in Thermal Gauge Theories

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    We investigate the thermal correlator of the trace of the energy-momentum tensor in the SU(3) Yang-Mills theory. Our goal is to constrain the spectral function in that channel, whose low-frequency part determines the bulk viscosity. We focus on the thermal modification of the spectral function, ρ(ω,T)ρ(ω,0)\rho(\omega,T)-\rho(\omega,0). Using the operator-product expansion we give the high-frequency behavior of this difference in terms of thermodynamic potentials. We take into account the presence of an exact delta function located at the origin, which had been missed in previous analyses. We then combine the bulk sum rule and a Monte-Carlo evaluation of the Euclidean correlator to determine the intervals of frequency where the spectral density is enhanced or depleted by thermal effects. We find evidence that the thermal spectral density is non-zero for frequencies below the scalar glueball mass mm and is significantly depleted for mω3mm\lesssim\omega\lesssim 3m.Comment: (1+25) pages, 6 figure

    Science and technology parks as innovation intermediaries for green innovation

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    Author's accepted version (postprint).This is an Accepted Manuscript of an article published by Springer in Lecture Notes in Mechanical Engineering on 18/08/2020.Available online: https://link.springer.com/chapter/10.1007/978-3-030-48021-9_101This paper discusses how science and technology parks (STPs) act as intermediaries for projects regarding green innovation. The empirical evidence is gathered through a case study of the City of Knowledge in Panama. For the recent Panama channel’s expansion, local authorities faced the need to improve the water resource management to secure enough fresh water for the canal’s operation. We inductively analysed data from 24 interviews, documents and participant observer. Preliminary results show the intermediation of STPs in green innovation processes in three phases: a first intermediation process is the STP as a hub for knowledge generation, including training for entrepreneurship. A second stage of the park as an innovation intermediary regards to an arena for knowledge and technology transfer, including collaboration with universities. A third phase implies financing and brokerage of green innovation between local and global actors. Our results challenge the existing literature about STPs with a narrow focus on economic spillover effects, or as hubs for attracting and developing cutting-edge technological innovations.acceptedVersio
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