35,463 research outputs found
No association of CTLA-4 polymorphisms with susceptibility to Behcet disease
Background: Cytotoxic T lymphocyte-associated antigen 4 (CTLA-4) is a key negative regulator of T lymphocytes and has been shown to be associated with a number of autoimmune diseases. The present study was performed to assess the association between CTLA-4 polymorphisms and Behcet disease (BD) in Chinese patients. Methods: Two hundred and twenty-eight BD patients and 207 controls were analysed for four single nucleotide polymorphisms (SNPs) (21661A/G, 2318C/T, + 49G/A and CT60G/A) in the CTLA-4 gene by PCR-restriction fragment length polymorphism (RFLP) analysis. The association between SNP +49A/G and BD in Chinese population as well as other ethnic groups was analysed by meta-analysis. Results: No association could be detected between CTLA-4 SNPs or haplotypes and BD. Also, no association was observed between CTLA-4 polymorphisms and BD subgroups, stratified by clinical features. A meta-analysis showed that there was no heterogeneity between studies (p = 0.60, I-2 = 0%) and that CTLA-4 SNP + 49 was not associated with BD (overall effect: Z = 0.26, p = 0.79). Conclusion: This study and a meta-analysis failed to demonstrate any association between the tested CTLA-4 polymorphisms and B
Coherent control of plasma dynamics
Coherent control of a system involves steering an interaction to a final
coherent state by controlling the phase of an applied field. Plasmas support
coherent wave structures that can be generated by intense laser fields. Here,
we demonstrate the coherent control of plasma dynamics in a laser wakefield
electron acceleration experiment. A genetic algorithm is implemented using a
deformable mirror with the electron beam signal as feedback, which allows a
heuristic search for the optimal wavefront under laser-plasma conditions that
is not known a priori. We are able to improve both the electron beam charge and
angular distribution by an order of magnitude. These improvements do not simply
correlate with having the `best' focal spot, since the highest quality vacuum
focal spot produces a greatly inferior electron beam, but instead correspond to
the particular laser phase that steers the plasma wave to a final state with
optimal accelerating fields
On Singularity Formation of a Nonlinear Nonlocal System
We investigate the singularity formation of a nonlinear nonlocal system. This
nonlocal system is a simplified one-dimensional system of the 3D model that was
recently proposed by Hou and Lei in [13] for axisymmetric 3D incompressible
Navier-Stokes equations with swirl. The main difference between the 3D model of
Hou and Lei and the reformulated 3D Navier-Stokes equations is that the
convection term is neglected in the 3D model. In the nonlocal system we
consider in this paper, we replace the Riesz operator in the 3D model by the
Hilbert transform. One of the main results of this paper is that we prove
rigorously the finite time singularity formation of the nonlocal system for a
large class of smooth initial data with finite energy. We also prove the global
regularity for a class of smooth initial data. Numerical results will be
presented to demonstrate the asymptotically self-similar blow-up of the
solution. The blowup rate of the self-similar singularity of the nonlocal
system is similar to that of the 3D model.Comment: 28 pages, 9 figure
Swift, XMM-Newton, and NuSTAR observations of PSR J2032+4127/MT91 213
We report our recent Swift, NuSTAR, and XMM-Newton X-ray and Lijiang optical
observations on PSR J2032+4127/MT91 213, the gamma-ray binary candidate with a
period of 45-50 years. The coming periastron of the system was predicted to be
in November 2017, around which high-energy flares from keV to TeV are expected.
Recent studies with Chandra and Swift X-ray observations taken in 2015/16
showed that its X-ray emission has been brighter by a factors of ~10 than that
before 2013, probably revealing some on-going activities between the pulsar
wind and the stellar wind. Our new Swift/XRT lightcurve shows no strong
evidence of a single vigorous brightening trend, but rather several strong
X-ray flares on weekly to monthly timescales with a slowly brightening
baseline, namely the low state. The NuSTAR and XMM-Newton observations taken
during the flaring and the low states, respectively, show a denser environment
and a softer power-law index during the flaring state, implying that the pulsar
wind interacted with stronger stellar winds of the companion to produce the
flares. These precursors would be crucial in studying the predicted giant
outburst from this extreme gamma-ray binary during the periastron passage in
late 2017.Comment: 6 pages, including 3 figures and 2 tables. Accepted for publication
in Ap
Charged Higgs Boson Pairs at the LHC
We compute the cross section for pair production of charged Higgs bosons at
the LHC and compare the three production mechanisms. The bottom-parton
scattering process is computed to NLO, and the validity of the bottom-parton
approach is established in detail. The light-flavor Drell-Yan cross section is
evaluated at NLO as well. The gluon fusion process through a one-loop amplitude
is then compared with these two results. We show how a complete sample of
events could look, in terms of total cross sections and distributions of the
heavy final states.Comment: 15 pages with 8 figure
Note on the Algebra of Screening Currents for the Quantum Deformed W-Algebra
With slight modifications in the zero modes contributions, the positive and
negative screening currents for the quantum deformed W-algebra W_{q,p}(g) can
be put together to form a single algebra which can be regarded as an elliptic
deformation of the universal enveloping algebra of \hat{g}, where g is any
classical simply-laced Lie algebra.Comment: LaTeX file, 9 pages. Errors in Serre relation corrected. Two
references to Awata,H. et al adde
Necessary and sufficient conditions for local creation of quantum discord
We show that a local channel cannot create quantum discord (QD) for zero QD
states of size if and only if either it is a completely decohering
channel or it is a nontrivial isotropic channel. For the qubit case this
propertiy is additionally characteristic to the completely decohering channel
or the commutativity-preserving unital channel. In particular, the exact forms
of the completely decohering channel and the commutativity-preserving unital
qubit channel are proposed. Consequently, our results confirm and improve the
conjecture proposed by X. Hu et al. for the case of and improve the
result proposed by A. Streltsov et al. for the qubit case. Furthermore, it is
shown that a local channel nullifies QD in any state if and only if it is a
completely decohering channel. Based on our results, some protocols of quantum
information processing issues associated with QD, especially for the qubit
case, would be experimentally accessible.Comment: 8 page
Soliton Solutions on Noncommutative Orbifold $ T^2/Z_4
In this paper, we explicitly construct a series of projectors on integral
noncommutative orbifold by extended constrution. They include
integration of two arbitary functions with symmetry. Our expressions
possess manifest symmetry. It is proved that the expression include all
projectors with minimal trace and in their standard expansions, the eigen value
functions of coefficient operators are continuous with respect to the arguments
and . Based on the integral expression, we alternately show the
derivative expression in terms of the similar kernal to the integral one.Since
projectors correspond to soliton solutions of the field theory on the
noncommutative orbifold, we thus present a series of corresponding solitons.Comment: 18 pages, no figure; referrences adde
Thermonuclear Ti-42(p, gamma)V-43 rate in type-I x-ray bursts
The thermonuclear rate of the Ti-42(p, gamma)V-43 reaction has been reevaluated based on a recent precise proton separation energy measurement of S-p(V-43) = 83 +/- 43 keV. The astrophysical impact of our new rates has been investigated through one-zone postprocessing type-I x-ray burst calculations. It shows that the new experimental value of S-p significantly affects the yields of species for A approximate to 40-45. As well, the precision of the recent experimental S-p value constrains these yields to better than a factor of 3.Peer reviewedFinal Accepted Versio
Modalities for Imaging of Prostate Cancer
Prostate cancer is the second most common cause of cancer deaths among males in the United States. Prostate screening by digital rectal examination and prostate-specific
antigen has shifted the diagnosis of prostate cancer to lower grade, organ confined
disease, adding to overdetection and overtreatment of prostate cancer. The new challenge
is in differentiating clinically relevant tumors from ones that may otherwise never have
become evident if not for screening. The rapid evolution of imaging modalities and the
synthesis of anatomic, functional, and molecular data allow for improved detection and
characterization of prostate cancer. However, the appropriate use of imaging is difficult
to define, as many controversial studies regarding each of the modalities and their utilities
can be found in the literature. Clinical practice patterns have been slow to adopt many of
these advances as a result. This review discusses the more established imaging
techniques, including Ultrasonography, Magnetic Resonance Imaging, MR Spectroscopy,
Computed Tomography, and Positron Emission Tomography. We also review several
promising techniques on the horizon, including Dynamic Contrast-Enhanced MRI,
Diffuse-Weighted Imaging, Superparamagnetic Nanoparticles, and Radionuclide
Scintigraphy
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