992 resultados para Generalized Functions


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Early pregnancy is characterized by complex interactions between blood vessels, leukocytes, and conceptus-derived trophoblasts within the gestational uterus. Uterine Natural Killer (uNK) cells become the most abundant leukocyte during decidualization and produce a wide array of angiogenic factors, yet little is known regarding their early pregnancy functions. To characterize the role(s) of uNK cells, whole mount in situ immunohistochemistry of live early implant sites was performed. A timecourse examination of murine early pregnancy (virgin, and gd4.5-9.5) implantation sites was performed. Comparison of Gd6.5, 8.5 and 9.5 implant sites from BALB/c+/+ controls (BALB/c) and BALB/c-Rag2-/-Il2rg-/- (alymphoid) identified anomalies that result from the absence of lymphocytes. In alymphoid decidua basalis, mesometrial angiogenesis was widespread but pruning of nascent vessels within alymphoid decidua basalis was deficient. As early gestation progressed, vessels of alymphoid decidua basalis showed no evidence for remodeling. Alymphoid implantation sites showed ~24h delay in uterine lumen closure and embryonic development. To determine if uNK cells would normalize the anomalies observed in alymphoid implantation sites, adoptive cell transfer of NK+ B- T- marrow to alymphoid mice was performed. All of the above anomalies were reversed by adoptive transfer of NK+B-T- marrow. My results suggest that uNK cells support vascular growth and development which ensures the decidua can support the growing conceptus early in pregnancy prior to formation and function of the placenta. Human decidual NK cells may fill similar roles and be important targets for strategies designed to correct intra-uterine growth restriction.

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We have evaluated the role played by BRCA1 in mediating the phenotypic response to a range of chemotherapeutic agents commonly used in cancer treatment. Here we provide evidence that BRCA1 functions as a differential mediator of chemotherapy-induced apoptosis. Specifically, we demonstrate that BRCA1 mediates sensitivity to apoptosis induced by antimicrotubule agents but conversely induces resistance to DNA-damaging agents. These data are supported by a variety of experimental models including cells with inducible expression of BRCA1, siRNA-mediated inactivation of endogenous BRCA1, and reconstitution of BRCA1-deficient cells with wild-type BRCA1. Most notably we demonstrate that BRCA1 induces a 10–1000-fold increase in resistance to a range of DNA-damaging agents, in particular those that give rise to double-strand breaks such as etoposide or bleomycin. In contrast, BRCA1 induces a >1000-fold increase in sensitivity to the spindle poisons, paclitaxel and vinorelbine. Fluorescence-activated cell sorter analysis demonstrated that BRCA1 mediates G2/M arrest in response to both antimicrotubule and DNA-damaging agents. However, poly(ADP-ribose) polymerase and caspase-3 cleavage assays indicate that the differential effect mediated by BRCA1 in response to these agents occurs through the inhibition or induction of apoptosis. Therefore, our data suggest that BRCA1 acts as a differential modulator of apoptosis depending on the nature of the cellular insult.

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The continuum distorted-wave eikonal-initial-state (CDW-EIS) theory of Crothers and McCann (Crothers DSF and McCann JF, 1983 J. Phys. B: At. Mol. Opt. Phys. 16 3229 ) used to describe ionization in ion-atom collisions is generalized (G) to GCDW-EIS, to incorporate the azimuthal ange dependence into the final-state wavefunction. This is accomplished by the analytic continuation of hydrogenic-like wavefunctions from below to above threshold, using parabolic coordinates and quantum numbers including magnetic quantum numbers, thus providing a more complete set of states. At impact energies lower than 25 ke V u^{-1}, the total CDW-EIS ionization cross section falls off, with decreasing energy, too quickly in comparison with experimental data by Crothers and McCann. The idea behind and motivation for the GCDW-EIS model is to improve the theory with respect to experiment, by including contributions from non-zero magnetic quantum numbers. We also therefore incidentally provide a new derivation of the theory of continuum distorted waves for zero magnetic quantum numbers while simultaneously generalizing it.

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A new approach to evaluating all multiple complex roots of analytical function f(z) confined to the specified rectangular domain of complex plane has been developed and implemented in Fortran code. Generally f (z), despite being holomorphic function, does not have a closed analytical form thereby inhibiting explicit evaluation of its derivatives. The latter constraint poses a major challenge to implementation of the robust numerical algorithm. This work is at the instrumental level and provides an enabling tool for solving a broad class of eigenvalue problems and polynomial approximations.

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The study of alternative combination rules in DS theory when evidence is in conflict has emerged again recently as an interesting topic, especially in data/information fusion applications. These studies have mainly focused on investigating which alternative would be appropriate for which conflicting situation, under the assumption that a conflict is identified. The issue of detection (or identification) of conflict among evidence has been ignored. In this paper, we formally define when two basic belief assignments are in conflict. This definition deploys quantitative measures of both the mass of the combined belief assigned to the emptyset before normalization and the distance between betting commitments of beliefs.We argue that only when both measures are high, it is safe to say the evidence is in conflict. This definition can be served as a prerequisite for selecting appropriate combination rules.