912 research outputs found

    Regulation of AE2-mediated Cl− Transport by Intracellular or by Extracellular pH Requires Highly Conserved Amino Acid Residues of the AE2 NH2-terminal Cytoplasmic Domain

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    We reported recently that regulation by intracellular pH (pHi) of the murine Cl−/HCO3− exchanger AE2 requires amino acid residues 310–347 of the polypeptide's NH2-terminal cytoplasmic domain. We have now identified individual amino acid residues within this region whose integrity is required for regulation of AE2 by pH. 36Cl− efflux from AE2-expressing Xenopus oocytes was monitored during variation of extracellular pH (pHo) with unclamped or clamped pHi, or during variation of pHi at constant pHo. Wild-type AE2–mediated 36Cl− efflux was profoundly inhibited by acid pHo, with a value of pHo(50) = 6.87 ± 0.05, and was stimulated up to 10-fold by the intracellular alkalinization produced by bath removal of the preequilibrated weak acid, butyrate. Systematic hexa-alanine [(A)6]bloc substitutions between aa 312–347 identified the greatest acid shift in pHo(50) value, ∼0.8 pH units in the mutant (A)6342–347, but only a modest acid-shift in the mutant (A)6336–341. Two of the six (A)6 mutants retained normal pHi sensitivity of 36Cl− efflux, whereas the (A)6 mutants 318–323, 336–341, and 342–347 were not stimulated by intracellular alkalinization. We further evaluated the highly conserved region between aa 336–347 by alanine scan and other mutagenesis of single residues. Significant changes in AE2 sensitivity to pHo and to pHi were found independently and in concert. The E346A mutation acid-shifted the pHo(50) value to the same extent whether pHi was unclamped or held constant during variation of pHo. Alanine substitution of the corresponding glutamate residues in the cytoplasmic domains of related AE anion exchanger polypeptides confirmed the general importance of these residues in regulation of anion exchange by pH. Conserved, individual amino acid residues of the AE2 cytoplasmic domain contribute to independent regulation of anion exchange activity by pHo as well as pHi

    On Power Suppressed Operators and Gauge Invariance in SCET

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    The form of collinear gauge invariance for power suppressed operators in the soft-collinear effective theory is discussed. Using a field redefinition we show that it is possible to make any power suppressed ultrasoft-collinear operators invariant under the original leading order gauge transformations. Our manipulations avoid gauge fixing. The Lagrangians to O(lambda^2) are given in terms of these new fields. We then give a simple procedure for constructing power suppressed soft-collinear operators in SCET_II by using an intermediate theory SCET_I.Comment: 15 pages, journal versio

    The nature of social dominance orientation: theorizing and measuring preferences for intergroup inequality using the new SDO₇ scale

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    A new conceptualization and measurement of social dominance orientation-individual differences in the preference for group based hierarchy and inequality-is introduced. In contrast to previous measures of social dominance orientation that were designed to be unidimensional, the new measure (SDO7) embeds theoretically grounded subdimensions of SDO-SDO-Dominance (SDO-D) and SDO-Egalitarianism (SDO-E). SDO-D constitutes a preference for systems of group-based dominance in which high status groups forcefully oppress lower status groups. SDO-E constitutes a preference for systems of group-based inequality that are maintained by an interrelated network of subtle hierarchy-enhancing ideologies and social policies. Confirmatory factor and criterion validity analyses confirmed that SDO-D and SDO-E are theoretically distinct and dissociate in terms of the intergroup outcomes they best predict. For the first time, distinct personality and individual difference bases of SDO-D and SDO-E are outlined. We clarify the construct validity of SDO by strictly assessing a preference for dominance hierarchies in general, removing a possible confound relating to support for hierarchy benefitting the ingroup. Consistent with this, results show that among members of a disadvantaged ethnic minority group (African Americans), endorsement of SDO7 is inversely related to ingroup identity. We further demonstrate these effects using nationally representative samples of U.S. Blacks and Whites, documenting the generalizability of these findings. Finally, we introduce and validate a brief 4-item measure of each dimension. This article importantly extends our theoretical understanding of one of the most generative constructs in social psychology, and introduces powerful new tools for its measurement

    Damping of Tensor Modes in Cosmology

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    An analytic formula is given for the traceless transverse part of the anisotropic stress tensor due to free streaming neutrinos, and used to derive an integro-differential equation for the propagation of cosmological gravitational waves. The solution shows that anisotropic stress reduces the squared amplitude by 35.6 % for wavelengths that enter the horizon during the radiation-dominated phase, independent of any cosmological parameters. This decreases the tensor temperature and polarization correlation functions for these wavelengths by the same amount. The effect is less for wavelengths that enter the horizon at later times. At the longest wavelengths the decrease in the tensor correlation functions due to neutrino free streaming ranges from 10.7% for ΩMh2=0.1\Omega_Mh^2=0.1 to 9.0% for ΩMh2=0.15\Omega_Mh^2=0.15. An Appendix gives a general proof that tensor as well as scalar modes satisfy a conservation law for perturbations outside the horizon, even when the anisotropic stress tensor is not negligible.Comment: 14 pages. The original version of this paper has been expanded to deal with perturbations of any wavelength. While for wavelengths short enough to enter the horizon during radiation dominance, temperature and polarization correlations are damped by 35.6%, at the longest wavelengths the damping is from 9.0% to 11%. An added Appendix gives a general proof that tensor as well as scalar modes satisfy a conservation law outside the horizon, even during neutrino decoupling. Some references are also adde

    Hard Scattering Factorization from Effective Field Theory

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    In this paper we show how gauge symmetries in an effective theory can be used to simplify proofs of factorization formulae in highly energetic hadronic processes. We use the soft-collinear effective theory, generalized to deal with back-to-back jets of collinear particles. Our proofs do not depend on the choice of a particular gauge, and the formalism is applicable to both exclusive and inclusive factorization. As examples we treat the pi-gamma form factor (gamma gamma* -> pi^0), light meson form factors (gamma* M -> M), as well as deep inelastic scattering (e- p -> e- X), Drell-Yan (p pbar -> X l+ l-), and deeply virtual Compton scattering (gamma* p -> gamma(*) p).Comment: 35 pages, 4 figures, typos corrected, journal versio

    Two-band second moment model and an interatomic potential for caesium

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    A semi-empirical formalism is presented for deriving interatomic potentials for materials such as caesium or cerium which exhibit volume collapse phase transitions. It is based on the Finnis-Sinclair second moment tight binding approach, but incorporates two independent bands on each atom. The potential is cast in a form suitable for large-scale molecular dynamics, the computational cost being the evaluation of short ranged pair potentials. Parameters for a model potential for caesium are derived and tested

    Testing factorization in B -> D(*)X decays

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    In QCD the amplitude for B0 -> D(*)+pi- factorizes in the large Nc limit or in the large energy limit Q >> Lambda_QCD where Q = {m_b, m_c, m_b-m_c}. Data also suggests factorization in exclusive processes B-> D* pi+ pi- pi- pi0 and B-> D* omega pi-, however by themselves neither large Nc nor large Q can account for this. Noting that the condition for large energy release in B0-> D+ pi- is enforced by the SV limit, m_b, m_c >> m_b-m_c >> Lambda, we propose that the combined large Nc and SV limits justify factorization in B -> D(*) X. This combined limit is tested with the inclusive decay spectrum measured by CLEO. We also give exact large Nc relations among isospin amplitudes for B -> D(*)X and B -> D(*) D-bar(*)X, which can be used to test factorization through exclusive or inclusive measurements. Predictions for the modes B-> D(*) pi pi, B-> D(*)K K-bar and B-> D(*) D-bar(*) K are discussed using available data.Comment: 15 pages, 3 included .eps figures, minor change

    Consistent Anisotropic Repulsions for Simple Molecules

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    We extract atom-atom potentials from the effective spherical potentials that suc cessfully model Hugoniot experiments on molecular fluids, e.g., O2O_2 and N2N_2. In the case of O2O_2 the resulting potentials compare very well with the atom-atom potentials used in studies of solid-state propertie s, while for N2N_2 they are considerably softer at short distances. Ground state (T=0K) and room temperatu re calculations performed with the new NNN-N potential resolve the previous discrepancy between experimental and theoretical results.Comment: RevTeX, 5 figure

    Randomized phase III trial of consolidation therapy with bortezomib–lenalidomide–Dexamethasone (VRd) vs bortezomib–dexamethasone (Vd) for patients with multiple myeloma who have completed a dexamethasone based induction regimen

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    Long-awaited results from the the Southwest Oncology Group (SWOG) trial comparing bortezomib–lenalidomide-dexamethasone (VRd) versus lenalidomide-dexamethasone (Rd) as induction treatment for previously untreated multiple myeloma (MM) patients were recently presented (S0777).1 Results justified the early adoption of VRd in the frontline setting over 5 years ago by the NCCN based on Level 2A evidence according to their guidelines.2 The randomized study E1A05 also sought to evaluate VRd superiority over a doublet (Vd), but in the consolidation setting. The trial was closed to enrollment prematurely due to slow accrual. Results reported here include 48 enrolled patients.This study was coordinated by the ECOG-ACRIN Cancer Research Group (Robert L Comis, MD, and Mitchell D Schnall, MD, PhD, Group Co-Chairs) and supported by the National Cancer Institute of the National Institutes of Health under award numbers: CA180820, CA180794, CA21115, CA23318, CA66636, CA180790, CA13650, CA189956, CA35412, CA15488, CA180799 and CA21076.http://www.sherpa.ac.uk/romeo/issn/2044-5385/am2016Medical Oncolog
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