1,051 research outputs found
Computational analysis of third-grade liquid flow with cross diffusion effects: application to entropy modeling
The key goal of this current study is to analyze the entropy generation with cross diffusion effects. The third-grade type non-Newtonian fluid model is used in this study. The current flow problem is modelled with stretching plate. Modified Fourier heat flux is replaced the classical heat flux. The appropriate transformation is availed to convert the basic boundary layers equations into ODEs and then verified by homotopy algorithm. The consequences of various physical quantities on temperature, velocity, entropy and concentration profile are illustrated graphically
Tah1 helix-swap dimerization prevents mixed Hsp90 co-chaperone complexes
Specific co-chaperone adaptors facilitate the recruitment of client proteins to the Hsp90 system. Tah1 binds the C-terminal conserved MEEVD motif of Hsp90, thus linking an eclectic set of client proteins to the R2TP complex for their assembly and regulation by Hsp90. Rather than the normal complement of seven α-helices seen in other tetratricopeptide repeat (TPR) domains, Tah1 unusually consists of the first five only. Consequently, the methionine of the MEEVD peptide remains exposed to solvent when bound by Tah1. In solution Tah1 appears to be predominantly monomeric, and recent structures have failed to explain how Tah1 appears to prevent the formation of mixed TPR domain-containing complexes such as Cpr6-(Hsp90)2-Tah1. To understand this further, the crystal structure of Tah1 in complex with the MEEVD peptide of Hsp90 was determined, which shows a helix swap involving the fifth α-helix between two adjacently bound Tah1 molecules. Dimerization of Tah1 restores the normal binding environment of the bound Hsp90 methionine residue by reconstituting a TPR binding site similar to that in seven-helix-containing TPR domain proteins. Dimerization also explains how other monomeric TPR-domain proteins are excluded from forming inappropriate mixed co-chaperone complexes
Frozen and Invariant Quantum Discord under Local Dephasing Noise
In this chapter, we intend to explore and review some remarkable dynamical
properties of quantum discord under various different open quantum system
models. Specifically, our discussion will include several concepts connected to
the phenomena of time invariant and frozen quantum discord. Furthermore, we
will elaborate on the relation of these two phenomena to the non-Markovian
features of the open system dynamics and to the usage of dynamical decoupling
protocols.Comment: 29 pages, 8 figure
New Physics in b -> s mu+ mu-: CP-Conserving Observables
We perform a comprehensive study of the impact of new-physics operators with
different Lorentz structures on decays involving the b -> s mu+ mu- transition.
We examine the effects of new vector-axial vector (VA), scalar-pseudoscalar
(SP) and tensor (T) interactions on the differential branching ratios and
forward-backward asymmetries (A_{FB}'s) of Bsbar -> mu+ mu-, Bdbar -> Xs mu+
mu-, Bsbar -> mu+ mu- gamma, Bdbar -> Kbar mu+ mu-, and Bdbar -> K* mu+ mu-,
taking the new-physics couplings to be real. In Bdbar -> K* mu+ mu-, we further
explore the polarization fraction f_L, the angular asymmetry A_T^{(2)}, and the
longitudinal-transverse asymmetry A_{LT}. We identify the Lorentz structures
that would significantly impact these observables, providing analytical
arguments in terms of the contributions from the individual operators and their
interference terms. In particular, we show that while the new VA operators can
significantly enhance most of the asymmetries beyond the Standard Model
predictions, the SP and T operators can do this only for A_{FB} in Bdbar ->
Kbar mu+ mu-.Comment: 54 pages, JHEP format, 45 figures (included). 5/6/2013: typos in K*
mu mu angular coefficients corrected, typos in Eq. (D.12) corrected, added a
missing term in I3LT in Eq. (D.16). Numerical analysis unchange
Corporate Social Responsibility and Islamic Financial Institutions (IFIs): Management Perceptions from IFIs in Bahrain
Islamic finance is gaining greater attention in the finance industry, and this paper analyses how Islamic financial institutions (IFIs) are responding to the welfare needs of society. Using interview data with managers and content analysis of the disclosures, this study attempts to understand management perceptions of corporate social
responsibility (CSR) in IFIs. A thorough understanding of CSR by managers, as evident in the interviews, has not been translated fully into practice. The partial use of IFIs’ potential role in social welfare would add further challenges in the era of financialisation
An improved observable for the forward-backward asymmetry in B -> K* l+ l- and Bs -> phi l+ l-
We study the decay B -> K* l+ l- in the QCD factorization approach and
propose a new integrated observable whose dependence on the form factors is
almost negligible, consequently the non--perturbative error is significantly
reduced and indeed its overall theoretical error is dominated by perturbative
scale uncertainties. The new observable we propose is the ratio between the
integrated forward--backward asymmetry in the [4,6] GeV^2 and [1,4] GeV^2
dilepton invariant mass bins. This new observable is particularly interesting
because, when compared to the location of the zero of the FBA spectrum, it is
experimentally easier to measure and its theoretical uncertainties are almost
as small; moreover it displays a very strong dependence on the phase of the
Wilson coefficient C_10 that is otherwise only accessible through complicated
CP violating asymmetries. We illustrate the new physics sensitivity of this
observable within the context of few extensions of the Standard Model, namely
the SM with four generations, an MSSM with non--vanishing source of flavor
changing neutral currents in the down squark sector and a Z' model with tree
level flavor changing couplings.Comment: 19 pages, 7 figure
A New Era in the Quest for Dark Matter
There is a growing sense of `crisis' in the dark matter community, due to the
absence of evidence for the most popular candidates such as weakly interacting
massive particles, axions, and sterile neutrinos, despite the enormous effort
that has gone into searching for these particles. Here, we discuss what we have
learned about the nature of dark matter from past experiments, and the
implications for planned dark matter searches in the next decade. We argue that
diversifying the experimental effort, incorporating astronomical surveys and
gravitational wave observations, is our best hope to make progress on the dark
matter problem.Comment: Published in Nature, online on 04 Oct 2018. 13 pages, 1 figur
Structural basis for phosphorylation-dependent recruitment of tel2 to hsp90 by pih1
Client protein recruitment to the Hsp90 system depends on cochaperones that bind the client and Hsp90 simultaneously and facilitate their interaction. Hsp90 involvement in the assembly of snoRNPs, RNA polymerases, PI3-kinase-like kinases, and chromatin remodeling complexes depends on the TTT (Tel2-Tti1-Tti2), and R2TP complexes-consisting of the AAA-ATPases Rvb1 and Rvb2, Tah1 (Spagh/RPAP3 in metazoa), and Pih1 (Pih1D1 in humans)-that together provide the connection to Hsp90. The biochemistry underlying R2TP function is still poorly understood. Pih1 in particular, at the heart of the complex, has not been described at a structural level, nor have the multiple protein-protein interactions it mediates been characterized. Here we present a structural and biochemical analysis of Hsp90-Tah1-Pih1, Hsp90-Spagh, and Pih1D1-Tel2 complexes that reveal a domain in Pih1D1 specific for binding CK2 phosphorylation sites, and together define the structural basis by which the R2TP complex connects the Hsp90 chaperone system to the TTT complex
Significant ophthalmoarthropathy associated with ectodermal dysplasia in a child with Marshall-Stickler overlap: a case report
© 2008 Al Kaissi et al; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution Licens
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