269 research outputs found
Pairing symmetry and properties of iron-based high temperature superconductors
Pairing symmetry is important to indentify the pairing mechanism. The
analysis becomes particularly timely and important for the newly discovered
iron-based multi-orbital superconductors. From group theory point of view we
classified all pairing matrices (in the orbital space) that carry irreducible
representations of the system. The quasiparticle gap falls into three
categories: full, nodal and gapless. The nodal-gap states show conventional
Volovik effect even for on-site pairing. The gapless states are odd in orbital
space, have a negative superfluid density and are therefore unstable. In
connection to experiments we proposed possible pairing states and implications
for the pairing mechanism.Comment: 4 pages, 1 table, 2 figures, polished versio
Challenges of information security incident learning: An industrial case study in a Chinese healthcare organization
Ghrelin Attenuates the Osteoblastic Differentiation of Vascular Smooth Muscle Cells through the ERK Pathway
Vascular calcification results from osteoblastic differentiation of vascular smooth muscle cells (VSMCs) and is a major risk factor for cardiovascular events. Ghrelin is a newly discovered bioactive peptide that acts as a natural endogenous ligand of the growth hormone secretagog receptor (GHSR). Several studies have identified the protective effects of ghrelin on the cardiovascular system, however research on the effects and mechanisms of ghrelin on vascular calcification is still quite rare. In this study, we determined the effect of ghrelin on osteoblastic differentiation of VSMCs and investigated the mechanism involved using the two universally accepted calcifying models of calcifying vascular smooth muscle cells (CVSMCs) and beta-glycerophosphate (beta-GP)-induced VSMCs. Our data demonstrated that ghrelin inhibits osteoblastic differentiation and mineralization of VSMCs due to decreased alkaline phosphatase (ALP) activity, Runx2 expression, bone morphogenetic protein-2 (BMP-2) expression and calcium content. Further study demonstrated that ghrelin exerted this suppression effect via an extracellular signal-related kinase (ERK)-dependent pathway and that the suppression effect of ghrelin was time dependent and dose dependent. Furthermore, inhibition of the growth hormone secretagog receptor (GHSR), the ghrelin receptor, by siRNA significantly reversed the activation of ERK by ghrelin. In conclusion, our study suggests that ghrelin may inhibit osteoblastic differentiation of VSMCs through the GHSR/ERK pathway
A Glutamic Acid-Rich Protein Identified in Verticillium dahliae from an Insertional Mutagenesis Affects Microsclerotial Formation and Pathogenicity
Verticillium dahliae Kleb. is a phytopathogenic fungus that causes wilt disease in a wide range of crops, including cotton. The life cycle of V. dahliae includes three vegetative phases: parasitic, saprophytic and dormant. The dormant microsclerotia are the primary infectious propagules, which germinate when they are stimulated by root exudates. In this study, we report the first application of Agrobacterium tumefaciens-mediated transformation (ATMT) for construction of insertional mutants from a virulent defoliating isolate of V. dahliae (V592). Changes in morphology, especially a lack of melanized microsclerotia or pigmentation traits, were observed in mutants. Together with the established laboratory unimpaired root dip-inoculation approach, we found insertional mutants to be affected in their pathogenicities in cotton. One of the genes tagged in a pathogenicity mutant encoded a glutamic acid-rich protein (VdGARP1), which shared no significant similarity to any known annotated gene. The vdgarp1 mutant showed vigorous mycelium growth with a significant delay in melanized microsclerotial formation. The expression of VdGARP1 in the wild type V529 was organ-specific and differentially regulated by different stress agencies and conditions, in addition to being stimulated by cotton root extract in liquid culture medium. Under extreme infertile nutrient conditions, VdGARP1 was not necessary for melanized microsclerotial formation. Taken together, our data suggest that VdGARP1 plays an important role in sensing infertile nutrient conditions in infected cells to promote a transfer from saprophytic to dormant microsclerotia for long-term survival. Overall, our findings indicate that insertional mutagenesis by ATMT is a valuable tool for the genome-wide analysis of gene function and identification of pathogenicity genes in this important cotton pathogen
Point contact Andreev reflection spectroscopy of NdFeAsO_0.85
The newly discovered oxypnictide family of superconductors show very high
critical temperatures of up to 55K. Whilst there is growing evidence that
suggests a nodal order parameter, point contact Andreev reflection spectroscopy
can provide crucial information such as the gap value and possibly the number
of energy gaps involved. For the oxygen deficient NdFeAsO0.85 with a Tc of
45.5K, we show that there is clearly a gap value at 4.2K that is of the order
of 7meV, consistent with previous studies on oxypnictides with lower Tc.
Additionally, taking the spectra as a function of gold tip contact pressure
reveals important changes in the spectra which may be indicative of more
complex physics underlying this structure.Comment: 11 pages, 3 figures. New references included, extra discussion. This
version is accepted in Superconductor Science and Technolog
Production of doubly-charged baryon in annihilation at energies from 2.3094 to 2.6464 GeV
The processes and
are studied for the first
time with of annihilation data collected with
the BESIII detector at center-of-mass energies from GeV to
GeV. No significant signal for the
process is observed and the upper limit of the Born cross section is estimated
at each energy point. For the process , a significant signal is observed at center-of-mass energies
near 2.6454 GeV and the corresponding Born cross section is reported.Comment: 10 pages, 4 figure
Measurement of the cross section of at center-of-mass energies between 3.510 and 4.843 GeV
Using collision data corresponding to a total integrated luminosity
of 12.9 collected with the BESIII detector at the BEPCII collider,
the exclusive Born cross sections and the effective form factors of the
reaction are measured via the single
baryon-tag method at 23 center-of-mass energies between 3.510 and 4.843 GeV.
Evidence for the decay is observed
with a significance of 4.5 by analyzing the measured cross sections
together with earlier BESIII results. For the other charmonium(-like) states
, , , , , and ,
no significant signal of their decay to is found. For these
states, upper limits of the products of the branching fraction and the
electronic partial width at the 90% confidence level are provided.Comment: 18 pages, 10 pages, 4 table
First Observation of a Three-Resonance Structure in {non-open} Charm Hadrons
We report the measurement of the cross sections for
{nOCH} (nOCH stands for non-open charm hadrons) with
improved precision at center-of-mass energies from 3.645 to 3.871 GeV. We
observe for the first time a three-resonance structure in the energy-dependent
lineshape of the cross sections, which are , and with significances of ,
, and , respectively. The is observed
for the first time. We found two solutions in analysis of the cross sections.
For solution I [solution II], we measure the mass, the total width and the
product of electronic width and nOCH decay branching fraction to be [] MeV/, [] MeV, and [] eV for the , respectively. In addition, we
measure the branching fractions {nOCH} for the first time, and {nOCH}. Moreover, we determine the open-charm (OC) branching fraction
{OC}, which supports the interpretation of as an OC pair molecular state, but contained a simple four-quark state
component. The first uncertainties are from fits to the cross sections, and the
second are systematic
Measurements of the branching fractions of the inclusive decays D0(D+)→π+π+π−X
Using eþe− annihilation data corresponding to an integrated luminosity of 2.93 fb−1 taken at a center-of mass energy of 3.773 GeV with the BESIII detector, we report the first measurements of the branching
fractions of the inclusive decays D0 → πþπþπ−X and Dþ → πþπþπ−X, where pions from K0
S decays have
been excluded from the πþπþπ− system and X denotes any possible particle combination. The branching
fractions of D0ðDþÞ → πþπþπ−X are determined to be BðD0 → πþπþπ−XÞ¼ð17.60 0.11 0.22Þ%
and BðDþ → πþπþπ−XÞ¼ð15.25 0.09 0.18Þ%, where the first uncertainties are statistical and the
second systematic
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