4,739 research outputs found
Ballistic Thermal Transistor of Dielectric Four-terminal Nanostructures
We report a theoretical model for a thermal transistor in dielectric
four-terminal nanostructures based on mesoscopic ballistic phonon transport, in
which a steady thermal flow condition of system is obtained to set up the
temperature field effect of gate. In the environment, thermal flow shows the
transisting behaviors at low temperatures: saturation, asymmetry, and
rectification. The phenomena can be explained reasonably by the nonlinear
variation of the temperature dependence of propagating phonon modes in
terminals. The results suggest the possibility of the novel nano-thermal
transistor fabrication
Variation of Mycobacterium tuberculosis antigen-specific IFN-γ and IL-17 responses in healthy tuberculin skin test (TST)-positive human subjects.
ObjectiveTo determine the variation of IFN-γ and IL-17 responses to M. tuberculosis antigens in healthy TST+ humans.MethodsWe isolated peripheral blood mononuclear cells from 21 TST+ healthy adults, stimulated them with phytohemagglutinin (PHA), PPD, Ag85B, ESAT-6, and live M. bovis BCG, and assayed IFN-γ and IL-17 secretion by ELISA in supernatants after 24 or 72 hours of incubation respectively.ResultsAs in other studies, we found a wide range of IFN-γ responses to M. tuberculosis antigens; the variation significantly exceeded that observed in the same donors to the polyclonal T cell stimulus, phytohemagglutinin (PHA). In addition, we assayed IL-17 secretion in response to the same stimuli, and found less subject-to-subject variation. Analysis of the ratio of IFN-γ to IL-17 secretion on a subject-to-subject basis also revealed a wide range, with the majority of results distributed in a narrow range, and a minority with extreme results all of which were greater than that in the majority of subjects. The data suggest that study of exceptional responses to M. tuberculosis antigens may reveal immunologic correlates with specific outcomes of M. tuberculosis infection.ConclusionVariation of IFNγ and IFN-γ/IL-17 responses to mycobacterial antigens exceeds that of responses to the polyclonal stimulus, PHA, in TST positive healthy humans. This indicates a quantitative spectrum of human immune responses to infection with M. tuberculosis. Since the outcome of human infection with M. tuberculosis varies greatly, systematic study of multiple immune responses to multiple antigens is likely to reveal correlations between selected immune responses and the outcomes of infection
Fast primal-dual algorithms via dynamics for linearly constrained convex optimization problems
By time discretization of a primal-dual dynamical system, we propose an
inexact primal-dual algorithm, linked to the Nesterov's acceleration scheme,
for the linear equality constrained convex optimization problem. We also
consider an inexact linearized primal-dual algorithm for the composite problem
with linear constrains. Under suitable conditions, we show that these
algorithms enjoy fast convergence properties. Finally, we study the convergence
properties of the primal-dual dynamical system to better understand the
accelerated schemes of the proposed algorithms. We also report numerical
experiments to demonstrate the effectiveness of the proposed algorithms
Fast convergence of primal-dual dynamics and algorithms with time scaling for linear equality constrained convex optimization problems
We propose a primal-dual dynamic with time scaling for a linear equality
constrained convex optimization problem, which consists of a second-order ODE
for the primal variable and a first-order ODE for the dual variable. Without
assuming strong convexity, we prove its fast convergence property and show that
the obtained fast convergence property is preserved under a small perturbation.
We also develop an inexact primal-dual algorithm derived by a time
discretization, and derive the fast convergence property matching that of the
underlying dynamic. Finally, we give numerical experiments to illustrate the
validity of the proposed algorithm
Violations of the weak cosmic censorship conjecture in the higher dimensional black holes with pressure
We adopt the energy momentum relation of charged particles to study the
thermodynamics laws and weak cosmic censorship conjecture of -dimensional
AdS black holes in different phase spaces by considering charged
particle absorption. In the normal phase space, it turns out that the laws of
thermodynamic and the weak cosmic censorship conjecture are valid. In the
extended phase space, though the first law of thermodynamics is valid, the
second law of thermodynamics is invalid. More interestingly, the weak cosmic
censorship conjecture is shown to be violated only in higher-dimensional
near-extremal AdS black holes. In addition, the magnitudes of the
violations for both the second law and weak cosmic censorship conjecture are
dependent on the charge , constant scalar curvature , AdS radius
, dimension parameters , and their variations.Comment: Accepted by Eur. Phys. J.
Cloning and selection of reference genes for gene expression studies in Ananas comosus
Full length mRNA sequences of Ac-β-actin and Ac-gapdh, and partial mRNA sequences of Ac-18SrRNA and Ac-ubiquitin were cloned from pineapple in this study. The four genes were tested as housekeeping genes in three experimental sets. GeNorm and NormFinder analysis revealed that β-actin was the most appropriate reference gene for qPCR analysis of callus under induction conditions and in different tissue types, meanwhile, 18SrRNA was the most stable reference gene during organ development. Gapdh was the most unstable gene in all tested experimental sets. Transcript level analysis result of AcSERK1 in stressed callus normalized by β-actin and 18SrRNA further confirmed that reference genes selected in this study were suitable for transcript level analysis of pineapple. The expression pattern of AcSERK1 during somatic embryogenesis normalized by β-actin coincided with the cytological features of calluses during somatic embryogenesis. These results will enable more accurate and reliable normalization of qPCR results for transcription analysis in pineapple. Keywords: Reference genes, qPCR, pineapple, geNorm, NormFinder African Journal of Biotechnology Vol. 11(29), pp. 7424-7433, 10 April, 201
Study of pentaquark system in the Chiral Quark Model
With the discovery of some hidden-charm pentaquark resonances by the LHCb
Collaboration, investigations of pentaquark states containing heavy quarks have
aroused the interest of theorists. We study herein ( or
, or ) pentaquark system, in the framework of the chiral quark
model. In consequence, some charmed and bottomed pentaquarks are considered to
exist by five-body dynamical calculations. In the charm sector,
and are
possible candidates of and , respectively.
Besides, two high-spin states, and
, are also found in the energy region of GeV. In the bottom sector, ,
could be candidates of
and , respectively. And
and are found in the energy region of GeV. and are expected as
compact states, while , , and
are expected as molecular states.Comment: 11 pages, 1 figur
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