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The SH3 domain of p56lck binds to proline-rich sequences in the cytoplasmic domain of CD2.
CD2, a cell surface glycoprotein expressed on T cells and natural killer cells, can couple to signaling pathways that result in T cell proliferation. An Src-like protein tyrosine kinase, p56lck, coprecipitates with CD2, and perturbation of CD2 by monoclonal antibodies results in an increase in the activity of p56lck, suggesting that an interaction with p56lck contributes to CD2-mediated signaling. Herein, we investigate the mechanism by which CD2 associates with p56lck. We demonstrate that CD2 and p56lck associate when coexpressed in nonlymphoid cells, that this association requires the cytoplasmic domain of CD2, and that the SH3 domain of p56lck mediates its interactions with CD2. Using truncation mutants of CD2, we identify two regions in the cytoplasmic domain of CD2 involved in binding p56lck. Each region contains a proline-rich sequence that, in the form of a synthetic peptide, directly binds p56lck. Thus, proline-rich sequences in the cytoplasmic domain of CD2 allow this transmembrane receptor to bind to the SH3 domain of p56lck
Frame Analysis: Studentsâ Construction of Involvement and Noninvolvement in the College Classroom
Frames and frame analysis examines the individualâs constructions of reality instead of societyâs social constructions. The aim of this qualitative study is to explore college studentsâ (N = 434) construction of involvement and noninvolvement in the classroom from a frame analysis perspective. Six themes emerged from studentsâ descriptions of their perceptions of self and other studentsâ in-class involvement (e.g., active involvement), and eight themes emerged from descriptions of self and other studentsâ in-class noninvolvement (e.g., student passivity). Overall, students are likely to perceive themselves as involved and other students as noninvolved, even when the classroom behaviors are similar (e.g., listening, taking notes)
Observation of quantum-Hall effect in gated epitaxial graphene grown on SiC (0001)
Epitaxial graphene films were formed on the Si-face of semi-insulating 4H-SiC
substrates by a high temperature sublimation process. A high-k gate stack on
epitaxial graphene is realized by inserting a fully oxidized nanometer thin
aluminum film as a seeding layer followed by an atomic-layer deposition
process. The electrical properties of epitaxial graphene films are sustained
after gate stack formation without significant degradation. At low
temperatures, the quantum-Hall effect in Hall resistance is observed along with
pronounced Shubnikov-de Hass oscillations in diagonal magneto-resistance of
gated epitaxial graphene on SiC (0001).Comment: 2 new references adde
Solutions of Higher Dimensional Gauss-Bonnet FRW Cosmology
We examine the effect on cosmological evolution of adding a Gauss-Bonnet term
to the standard Einstein-Hilbert action for a (1 + 3)+ d dimensional
Friedman-Robertson-Walker (FRW) metric. By assuming that the additional
dimensions compactify as a power law as the usual 3 spatial dimensions expand,
we solve the resulting dynamical equations and find that the solution may be of
either de Sitter or Kasner form depending upon whether the Gauss-Bonnet term or
the Einstein term dominates.Comment: 10 pages, references added/corrected, accepted for publication in
General Relativity and Gravitatio
General Relativity as Classical Limit of Evolutionary Quantum Gravity
We analyze the dynamics of the gravitational field when the covariance is
restricted to a synchronous gauge. In the spirit of the Noether theorem, we
determine the conservation law associated to the Lagrangian invariance and we
outline that a non-vanishing behavior of the Hamiltonian comes out. We then
interpret such resulting non-zero ``energy'' of the gravitational field in
terms of a dust fluid. This new matter contribution is co-moving to the slicing
and it accounts for the ``materialization'' of a synchronous reference from the
corresponding gauge condition. Further, we analyze the quantum dynamics of a
generic inhomogeneous Universe as described by this evolutionary scheme,
asymptotically to the singularity. We show how the phenomenology of such a
model overlaps the corresponding Wheeler-DeWitt picture. Finally, we study the
possibility of a Schr\"odinger dynamics of the gravitational field as a
consequence of the correspondence inferred between the ensemble dynamics of
stochastic systems and the WKB limit of their quantum evolution. We demonstrate
that the time dependence of the ensemble distribution is associated with the
first order correction in to the WKB expansion of the energy spectrum.Comment: 23 pages, to appear on Class. Quant. Gra
Semiclassical States in Quantum Cosmology: Bianchi I Coherent States
We study coherent states for Bianchi type I cosmological models, as examples
of semiclassical states for time-reparametrization invariant systems. This
simple model allows us to study explicitly the relationship between exact
semiclassical states in the kinematical Hilbert space and corresponding ones in
the physical Hilbert space, which we construct here using the group averaging
technique. We find that it is possible to construct good semiclassical physical
states by such a procedure in this model; we also discuss the sense in which
the original kinematical states may be a good approximation to the physical
ones, and the situations in which this is the case. In addition, these models
can be deparametrized in a natural way, and we study the effect of time
evolution on an "intrinsic" coherent state in the reduced phase space, in order
to estimate the time for this state to spread significantly.Comment: 21 pages, 1 figure; Version to be published in CQG; The discussion
has been slightly reorganized, two references added, and some typos correcte
Engagement of CD4 and CD8 expressed on immature thymocytes induces activation of intracellular tyrosine phosphorylation pathways.
Quantum Gravitational Corrections to the Real Klein-Gordon Field in the Presence of a Minimal Length
The (D+1)-dimensional -two-parameter Lorentz-covariant
deformed algebra introduced by Quesne and Tkachuk [C. Quesne and V. M. Tkachuk,
J. Phys. A: Math. Gen. \textbf {39}, 10909 (2006).], leads to a nonzero minimal
uncertainty in position (minimal length). The Klein-Gordon equation in a
(3+1)-dimensional space-time described by Quesne-Tkachuk Lorentz-covariant
deformed algebra is studied in the case where up to first order
over deformation parameter . It is shown that the modified Klein-Gordon
equation which contains fourth-order derivative of the wave function describes
two massive particles with different masses. We have shown that physically
acceptable mass states can only exist for which
leads to an isotropic minimal length in the interval . Finally, we have shown that the above estimation of
minimal length is in good agreement with the results obtained in previous
investigations.Comment: 10 pages, no figur
Patient Race/Ethnicity and Patient-Physician Race/Ethnicity Concordance in the Management of Cardiovascular Disease Risk Factors for Patients With Diabetes
OBJECTIVE Patient-physician race/ethnicity concordance can improve care for minority patients. However, its effect on cardiovascular disease (CVD) care and prevention is unknown. We examined associations of patient race/ethnicity and patient-physician race/ethnicity concordance on CVD risk factor levels and appropriate modification of treatment in response to high risk factor values (treatment intensification) in a large cohort of diabetic patients. RESEARCH DESIGN AND METHODS The study population included 108,555 adult diabetic patients in Kaiser Permanente Northern California in 2005. Probit models assessed the effect of patient race/ethnicity on risk factor control and treatment intensification after adjusting for patient and physician-level characteristics. RESULTS African American patients were less likely than whites to have A1C <8.0% (64 vs. 69%, P < 0.0001), LDL cholesterol <100 mg/dl (40 vs. 47%, P < 0.0001), and systolic blood pressure (SBP) <140 mmHg (70 vs. 78%, P < 0.0001). Hispanic patients were less likely than whites to have A1C <8% (62 vs. 69%, P < 0.0001). African American patients were less likely than whites to have A1C treatment intensification (73 vs. 77%, P < 0.0001; odds ratio [OR] 0.8 [95% CI 0.7-0.9]) but more likely to receive treatment intensification for SBP (78 vs. 71%, P < 0.0001; 1.5 [1.3-1.7]). Hispanic patients were more likely to have LDL cholesterol treatment intensification (47 vs. 45%, P < 0.05; 1.1 [1.0-1.2]). Patient-physician race/ethnicity concordance was not significantly associated with risk factor control or treatment intensification. CONCLUSIONS Patient race/ethnicity is associated with risk factor control and treatment intensification, but patient-physician race/ethnicity concordance was not. Further research should investigate other potential drivers of disparities in CVD care
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