3,127 research outputs found

    Earnings and wealth inequality and income taxation: quantifying the tradeoffs of switching to a proportional income tax in the U.S.

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    This paper quantifies the steady-state aggregate, distributional, and mobility effects of switching the U.S. to a proportional income tax system.Income tax

    Pharmacological and Clinical Importance of Integrin Antagonists in Treatment of Cancer

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    Integrins are heterodimeric molecules that are composed of 18 α -subunits and 8 β -subunits. They exist in 24 distinctive shapes based on combination of these sub-units and are mainly responsible for the adhesion of extracellular matrix (ECM) and immunoglobulin family molecules. Integrins mediate adhesion of epithelial cells to the basement membrane and also help in the migration, proliferation and survival of tumor cells. Studies also reveal that certain integrins act as markers for tumor cells and they also assist in both tumor progression and apoptosis. Studies reveal that unligated integrins in association with caspase 8 result in inhibition of ECM adhesion might result and integrin mediated death (IMD) on the other hand integrins in association with oncogenes or receptor tyrosine kinases can result in enhanced tumorigenesis. Among several types of integrins, αvβ 3 and α 5 β 1 have gained importance in anti-angiogenesis studie

    Inferring biomarkers for Mycobacterium avium subsp. paratuberculosis infection and disease progression in cattle using experimental data

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    Available diagnostic assays for Mycobacterium avium subsp. paratuberculosis (MAP) have poor sensitivities and cannot detect early stages of infection, therefore, there is need to find new diagnostic markers for early infection detection and disease stages. We analyzed longitudinal IFN-γ, ELISA-antibody and fecal shedding experimental sensitivity scores for MAP infection detection and disease progression. We used both statistical methods and dynamic mathematical models to (i) evaluate the empirical assays (ii) infer and explain biological mechanisms that affect the time evolution of the biomarkers, and (iii) predict disease stages of 57 animals that were naturally infected with MAP. This analysis confirms that the fecal test is the best marker for disease progression and illustrates that Th1/Th2 (IFN-γ/ELISA antibodies) assays are important for infection detection, but cannot reliably predict persistent infections. Our results show that the theoretical simulated macrophage-based assay is a potential good diagnostic marker for MAP persistent infections and predictor of disease specific stages. We therefore recommend specifically designed experiments to test the use of a based assay in the diagnosis of MAP infections

    Phase--coherence Effects in Antidot Lattices: A Semiclassical Approach to Bulk Conductivity

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    We derive semiclassical expressions for the Kubo conductivity tensor. Within our approach the oscillatory parts of the diagonal and Hall conductivity are given as sums over contributions from classical periodic orbits in close relation to Gutzwiller's trace formula for the density of states. Taking into account the effects of weak disorder and temperature we reproduce recently observed anomalous phase coherence oscillations in the conductivity of large antidot arrays.Comment: 11 pages, 2 figures available under request, RevTe

    Pharmacological and Clinical Importance of Integrin Antagonists in Treatment of Cancer

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    Integrins are heterodimeric molecules that are composed of 18 \ud α\ud -subunits and 8 \ud β\ud -subunits. They exist in 24\ud distinctive shapes based on combination of these sub-units and are mainly responsible for the adhesion of\ud extracellular matrix (ECM) and immunoglobulin family molecules. Integrins mediate adhesion of epithelial cells to the\ud basement membrane and also help in the migration, proliferation and survival of tumor cells. Studies also reveal that\ud certain integrins act as markers for tumor cells and they also assist in both tumor progression and apoptosis. Studies\ud reveal that unligated integrins in association with caspase 8 result in inhibition of ECM adhesion might result and\ud integrin mediated death (IMD) on the other hand integrins in association with oncogenes or receptor tyrosine kinases\ud can result in enhanced tumorigenesis. Among several types of integrins, \ud αvβ\ud 3 and \ud α\ud 5\ud β\ud 1 \ud have gained importance in\ud anti-angiogenesis studie

    Induction of B Cell Responses upon Experimental Infection of Neonatal Calves with Mycobacterium avium subsp. paratuberculosis

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    The objective of this study was to determine if experimental infection of neonatal calves with Mycobacterium avium subsp. paratuberculosis would invoke changes in the percentages of total B cells in the peripheral blood mononuclear cell population and of subpopulations of B cells as determined by CD5, CD25, and CD45RO markers during a 12-month period. Experimental infection groups included control (noninfected), oral (infected with M. avium subsp. paratuberculosis strain K-10), oral/DXM (pretreatment with dexamethasone before oral inoculation), i.p. (intraperitoneal inoculation), and oral/M (oral inoculation with mucosal scrapings from a cow with clinical disease) groups. Over the course of the study, the percentages of total B cells in nonstimulated and antigen-stimulated cell cultures increased for oral and i.p. group calves, with the highest percentages noted at 3 and 6 months. Oral/M group calves had increased percentages of activated B cells, as determined by CD5dim and CD5bright markers, at 9 and 12 months. Experimental infection by all methods resulted in increased expression of CD25 and CD45RO B cells early in the study, but the most significant results were observed at 12 months for oral/DXM and oral/M group calves. Immunoblot analyses with a whole-cell sonicate of M. avium subsp. paratuberculosis demonstrated the most reactivity with sera from i.p. group calves and the least reactivity with sera from oral group calves. Further evidence of M. avium subsp. paratuberculosis-specific antibody responses in the i.p. group calves was demonstrated using the ethanol vortex enzyme-linked immunosorbent assay (EvELISA) method. In summary, an induction of B cell responses was noted after experimental infection with M. avium subsp. paratuberculosis, with differences in responses noted according to the method of experimental inoculation

    Characterization of the second- and third-order nonlinear optical susceptibilities of monolayer MoS2_2 using multiphoton microscopy

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    We report second- and third-harmonic generation in monolayer MoS2_\mathrm{2} as a tool for imaging and accurately characterizing the material's nonlinear optical properties under 1560 nm excitation. Using a surface nonlinear optics treatment, we derive expressions relating experimental measurements to second- and third-order nonlinear sheet susceptibility magnitudes, obtaining values of χs(2)=2.0×1020|\chi_s^{(2)}|=2.0\times10^{-20} m2^2 V1^{-1} and for the first time for monolayer MoS2_\mathrm{2}, χs(3)=1.7×1028|\chi_s^{(3)}|=1.7\times10^{-28} m3^3 V2^{-2}. These sheet susceptibilities correspond to effective bulk nonlinear susceptibility values of χb(2)=2.9×1011|\chi_{b}^{(2)}|=2.9\times10^{-11} m V1^{-1} and χb(3)=2.4×1019|\chi_{b}^{(3)}|=2.4\times10^{-19} m2^2 V2^{-2}, accounting for the sheet thickness. Experimental comparisons between MoS2_\mathrm{2} and graphene are also performed, demonstrating \sim3.4 times stronger third-order sheet nonlinearity in monolayer MoS2_\mathrm{2}, highlighting the material's potential for nonlinear photonics in the telecommunications C band.Comment: Accepted by 2D Materials, 28th Oct 201

    Characterization of Ethanol Extracted Cell Wall Components of Mycobacterium avium Subsp. paratuberculosis

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    Antigens extracted using ethanol (EtOH) and incorporated in the EtOH vortex ELISA (EVELISA) test have previously shown high specificity and sensitivity for detecting Mycobacterium avium subspecies paratuberculosis (Map) and M. bovis infections in cattle. The objective of this study is to define the components present in the EtOH extract. We show that this extract is composed of lipid, carbohydrate, and proteins on the surface of the bacilli, and that EtOH removes the outer layer structure of Map which comprise these elements. To identify proteins, polyclonal antibodies to the EtOH prep were produced and used to screen a Map genomic expression library. Seven overlapping clones were identified with a single open reading frame, MAP_0585, common to all. MAP_0585, which encodes a hypothetical protein, was recombinantly produced and used to demonstrate strong reactivity in sera from hyperimmunized rabbits, but this protein is not strongly immunogenic in cattle with Johne’s disease. A panel of monoclonal antibodies was used to determine the presence of additional proteins in the EtOH extract. These antibodies demonstrated that a well-known antigen, termed MPB83, is present in M. bovis EtOH extracts and a fatty acid desaturase (MAP_2698c) is present in Map EtOH extracts, while lipoarabinomannan was common to both. The lipid and carbohydrate components of the extract were analyzed using thin layer chromatography and lectin binding, respectively. Lectin biding and protease treatment of the EtOH extract suggest the antigenic component is carbohydrate and not protein. These results give further insight into this important antigen prep for detecting mycobacterial diseases of cattle
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