231 research outputs found
Cardiomyocyte ionic currents in intact young and aged murine Pgc-1β-/- atrial preparations.
INTRODUCTION: Recent studies reported that energetically deficient murine Pgc-1β-/- hearts replicate age-dependent atrial arrhythmic phenotypes associated with their corresponding clinical conditions, implicating action potential (AP) conduction slowing consequent upon reduced AP upstroke rates. MATERIALS AND METHODS: We tested a hypothesis implicating Na+ current alterations as a mechanism underlying these electrophysiological phenotypes. We applied loose patch-clamp techniques to intact young and aged, WT and Pgc-1β-/-, atrial cardiomyocyte preparations preserving their in vivo extracellular and intracellular conditions. RESULTS AND DISCUSSION: Depolarising steps activated typical voltage-dependent activating and inactivating inward (Na+) currents whose amplitude increased or decreased with the amplitudes of the activating, or preceding inactivating, steps. Maximum values of peak Na+ current were independently influenced by genotype but not age or interacting effects of genotype and age on two-way ANOVA. Neither genotype, nor age, whether independently or interactively, influenced voltages at half-maximal current, or steepness factors, for current activation and inactivation, or time constants for recovery from inactivation following repolarisation. In contrast, delayed outward (K+) currents showed similar activation and rectification properties through all experimental groups. These findings directly demonstrate and implicate reduced Na+ in contrast to unchanged K+ current, as a mechanism for slowed conduction causing atrial arrhythmogenicity in Pgc-1β-/- hearts
Measurement of proton electromagnetic form factors in in the energy region 2.00-3.08 GeV
The process of is studied at 22 center-of-mass
energy points () from 2.00 to 3.08 GeV, exploiting 688.5~pb of
data collected with the BESIII detector operating at the BEPCII collider. The
Born cross section~() of is
measured with the energy-scan technique and it is found to be consistent with
previously published data, but with much improved accuracy. In addition, the
electromagnetic form-factor ratio () and the value of the
effective (), electric () and magnetic () form
factors are measured by studying the helicity angle of the proton at 16
center-of-mass energy points. and are determined with
high accuracy, providing uncertainties comparable to data in the space-like
region, and is measured for the first time. We reach unprecedented
accuracy, and precision results in the time-like region provide information to
improve our understanding of the proton inner structure and to test theoretical
models which depend on non-perturbative Quantum Chromodynamics
Search for the decay
We search for radiative decays into a weakly interacting neutral
particle, namely an invisible particle, using the produced through the
process in a data sample of
decays collected by the BESIII detector
at BEPCII. No significant signal is observed. Using a modified frequentist
method, upper limits on the branching fractions are set under different
assumptions of invisible particle masses up to 1.2 . The upper limit corresponding to an invisible particle with zero mass
is 7.0 at the 90\% confidence level
Precise Measurements of Branching Fractions for Meson Decays to Two Pseudoscalar Mesons
We measure the branching fractions for seven two-body decays to
pseudo-scalar mesons, by analyzing data collected at
GeV with the BESIII detector at the BEPCII collider. The branching fractions
are determined to be ,
,
,
,
,
,
,
where the first uncertainties are statistical, the second are systematic, and
the third are from external input branching fraction of the normalization mode
. Precision of our measurements is significantly improved
compared with that of the current world average values
Newly defined ATP-binding cassette subfamily B member 5 positive dermal mesenchymal stem cells promote healing of chronic iron-overload wounds via secretion of interleukin-1 receptor antagonist
In this study, we report the beneficial effects of a newly identified dermal cell subpopulation expressing the ATP‐binding cassette subfamily B member 5 (ABCB5) for the therapy of nonhealing wounds. Local administration of dermal ABCB5+‐derived mesenchymal stem cells (MSCs) attenuated macrophage‐dominated inflammation and thereby accelerated healing of full‐thickness excisional wounds in the iron‐overload mouse model mimicking the nonhealing state of human venous leg ulcers. The observed beneficial effects were due to interleukin‐1 receptor antagonist (IL‐1RA) secreted by ABCB5+‐derived MSCs, which dampened inflammation and shifted the prevalence of unrestrained proinflammatory M1 macrophages toward repair promoting anti‐inflammatory M2 macrophages at the wound site. The beneficial anti‐inflammatory effect of IL‐1RA released from ABCB5+‐derived MSCs on human wound macrophages was conserved in humanized NOD‐scid IL2rγ null mice. In conclusion, human dermal ABCB5+ cells represent a novel, easily accessible, and marker‐enriched source of MSCs, which holds substantial promise to successfully treat chronic nonhealing wounds in humans
Synthesis and characterization of CuO nanowires by a simple wet chemical method
We report a successful synthesis of copper oxide nanowires with an average diameter of 90 nm and lengths of several micrometers by using a simple and inexpensive wet chemical method. The CuO nanowires prepared via this method are advantageous for industrial applications which require mass production and low thermal budget technique. It is found that the concentration and the quantity of precursors are the critical factors for obtaining the desired one-dimensional morphology. Field emission scanning electron microscopy images indicate the influence of thioglycerol on the dispersity of the prepared CuO nanowires possibly due to the stabilization effect of the surface caused by the organic molecule thioglycerol. The Fourier transform infrared spectrum analysis, energy dispersive X-ray analysis, X-ray diffraction analysis, and X-ray photoemission spectrum analysis confirm clearly the formation of a pure phase high-quality CuO with monoclinic crystal structure
Observation of a structure in at from 2.05 to 3.08 GeV
The process has been studied for the
first time in detail using data sample collected with the BESIII detector at
the BEPCII collider at center of mass energies from 2.05 to 3.08 GeV. A
resonance with quantum numbers is observed with mass =
(2177.5 4.8 (stat) 19.5 (syst)) MeV/ and
width = (149.0 15.6 (stat) 8.9 (syst)) MeV with a
statistical significance larger than 10. The observed structure could
be identified with the , then the ratio of partial width between
the by BESIII and by BABAR is
( = 0.23 0.10 (stat) 0.18 (syst),
which is smaller than the prediction of the hybrid models by
several orders of magnitude
Measurements of the absolute branching fractions of decays
Based on 2.93~fb collision data taken at center-of-mass
energy of 3.773 GeV by the BESIII detector, we report the measurements of the
absolute branching fractions of , , , , , ,
, , and . The decays , , , , and are observed for the
first time. The branching fractions of the decays , , ,
and are measured with improved precision compared
to the world-average values.Comment: 11 pages, 5 figure
Model-independent determination of the relative strong-phase difference between and and its impact on the measurement of the CKM angle
Crucial inputs for a variety of -violation studies can be determined
through the analysis of pairs of quantum-entangled neutral mesons, which
are produced in the decay of the resonance. The relative
strong-phase parameters between and in the decays
are studied using 2.93~ of
annihilation data delivered by the BEPCII collider and collected by
the BESIII detector at a center-of-mass energy of 3.773 GeV. Results are
presented in regions of the phase space of the decay. These are the most
precise measurements to date of the strong-phase parameters in decays. Using these parameters, the associated uncertainty
on the Cabibbo-Kobayashi-Maskawa angle is expected to be
between and , for an analysis using the decay
, , where
represents a superposition of and states. This is a factor of
three smaller than that achievable with previous measurements. Furthermore,
these results provide valuable input for charm-mixing studies, other
measurements of violation, and the measurement of strong-phase parameters
for other -decay modes.Comment: 34 pages, 10 figure
Search for the semileptonic decay
Using of annihilation data collected at a
center-of-mass energy GeV with the BESIII detector operating
at the BEPCII collider, we search for the semileptonic decays into a
axial-vector meson for the first time. No significant signal
is observed for either charge combination. The upper limits on the product
branching fractions are and at the 90\% confidence level.Comment: 9 pages, 3 figure
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