283 research outputs found
Engineering and Assessing Cardiac Tissue Complexity
Cardiac tissue engineering is very much in a current focus of regenerative medicine research as it represents a promising strategy for cardiac disease modelling, cardiotoxicity testing and cardiovascular repair. Advances in this field over the last two decades have enabled the generation of human engineered cardiac tissue constructs with progressively increased functional capabilities. However, reproducing tissue-like properties is still a pending issue, as constructs generated to date remain immature relative to native adult heart. Moreover, there is a high degree of heterogeneity in the methodologies used to assess the functionality and cardiac maturation state of engineered cardiac tissue constructs, which further complicates the comparison of constructs generated in different ways. Here, we present an overview of the general approaches developed to generate functional cardiac tissues, discussing the different cell sources, biomaterials, and types of engineering strategies utilized to date. Moreover, we discuss the main functional assays used to evaluate the cardiac maturation state of the constructs, both at the cellular and the tissue levels. We trust that researchers interested in developing engineered cardiac tissue constructs will find the information reviewed here useful. Furthermore, we believe that providing a unified framework for comparison will further the development of human engineered cardiac tissue constructs displaying the specific properties best suited for each particular application
Phase formation processes and synthesis of solid solutions in Ca-R-Nb-M-O systems
During the study of the phase formation process in Ca-R-Nb-M-O systems (R=La, Bi, M=Mo, W), an attempt was made to obtain single-phase compounds of CaRNbMO8 composition by the standard ceramic technique. In addition, samples based on LaNbO4, CaWO4, BiNbO4 were also synthesized by the standard ceramic technique. The phase composition of the samples was studied by XRD analysis. The electrical conductivity of the obtained solid solutions and potential composite materials was investigated by impedance spectroscopy
The Dipion Mass Spectrum In e+e- Annihilation and tau Decay: A Dynamical (rho0, omega, phi) Mixing Approach
We readdress the problem of finding a simultaneous description of the pion
form factor data in e+e- annihilations and in tau decays. For this purpose, we
work in the framework of the Hidden Local Symmetry (HLS) Lagrangian and modify
the vector meson mass term by including the pion and kaon loop contributions.
This leads us to define the physical rho, omega and phi fields as linear
combinations of their ideal partners, with coefficients being meromorphic
functions of s, the square of the 4--momentum flowing into the vector meson
lines. This allows us to define a dynamical, i.e. s-dependent, vector meson
mixing scheme. The model is overconstrained by extending the framework in order
to include the description of all meson radiative (V P gamma and P gamma gamma
couplings) and leptonic (Ve+e- couplings) decays and also the isospin breaking
(omega/ phi --> pi+ pi-) decay modes. The model provides a simultaneous,
consistent and good description of the e+e- and tau dipion spectra. The
expression for pion form factor in the latter case is derived from those in the
former case by switching off the isospin breaking effects specific to e+e- and
switching on those for tau decays. Besides, the model also provides a good
account of all decay modes of the form V P gamma, Pgamma gamma as well as the
isospin breaking decay modes. It leads us to propose new reference values for
the rho^0 --> e+ e- and omega --> pi+ pi- partial widths which are part of our
description of the pion form factor. Other topics (phi --> K anti K, the rho
meson mass and width parameters) are briefly discussed. Therefore, we confirm
the 3.3 sigma discrepancy between the theoretical estimate of a_mu based on
e+e- and its direct BNL measurement.Comment: 71 pages, 8 figures. Accepted by EPJ C. Version 3: correct minor
typos, minor changes spread out into the text. Extension of Sections 12.2 and
12.3.5 and introduction of the new Appendix
Pion and Vector Meson Form Factors in the Kuperstein-Sonnenschein holographic model
We study phenomenological aspects of the holographic model of chiral symmetry
breaking recently introduced by Kuperstein and Sonnenschein (KS). As a first
step, we calculate the spectrum of vector and axial-vector mesons in the KS
model. We numerically compute various coupling constants of the mesons and
pions. Our analysis indicates that vector meson dominance is realized in this
model. The pion, vector meson and axial-vector meson form factors are obtained
and studied in detail. We find good agreement with QCD results. In particular,
the pion form factor closely matches available experimental data.Comment: v1: 27 pages, 9 figures, 4 tables; v2: minor changes, added more
general discussion of vector meson dominance; v3: minor changes and
additions, version accepted for publication in JHE
Vaginal and abdominal birth in attempts of independent labor in women with a scar on the uterus after a cesarean section
The aim of this study - was to assess the course and outcome of labor in pregnant women with a single uterine scar during trial of vaginal labor after CS.Цель исследования - оценить течение и исход родов у женщин с рубцом на матке после кесарева сечения (КС) при попытке вагинальных родо
Strange Quark Contributions to Parity-Violating Asymmetries in the Backward Angle G0 Electron Scattering Experiment
We have measured parity-violating asymmetries in elastic electron-proton and
quasi-elastic electron-deuteron scattering at Q^2 = 0.22 and 0.63 GeV^2. They
are sensitive to strange quark contributions to currents in the nucleon, and to
the nucleon axial current. The results indicate strange quark contributions of
< 10% of the charge and magnetic nucleon form factors at these four-momentum
transfers. We also present the first measurement of anapole moment effects in
the axial current at these four-momentum transfers.Comment: 5 pages, 2 figures, changed references, typo, and conten
Nuclear transparency and effective kaon-nucleon cross section from the A(e, e'K+) reaction
We have determined the transparency of the nuclear medium to kaons from
measurements on C, Cu, and Au targets.
The measurements were performed at the Jefferson Laboratory and span a range in
four-momentum-transfer squared Q=1.1 -- 3.0 GeV. The nuclear
transparency was defined as the ratio of measured kaon electroproduction cross
sections with respect to deuterium, (). We further
extracted the atomic number () dependence of the transparency as
parametrized by and, within a simple model assumption,
the in-medium effective kaon-nucleon cross sections. The effective cross
sections extracted from the electroproduction data are found to be smaller than
the free cross sections determined from kaon-nucleon scattering experiments,
and the parameter was found to be significantly larger than those
obtained from kaon-nucleus scattering. We have included similar comparisons
between pion- and proton-nucleon effective cross sections as determined from
electron scattering experiments, and pion-nucleus and proton-nucleus scattering
data.Comment: 7 pages, 5 figure
Spatial contrast sensitivity in adolescents with autism spectrum disorders
Adolescents with autism spectrum disorders (ASD) and typically developing (TD) controls underwent a rigorous psychophysical assessment that measured contrast sensitivity to seven spatial frequencies (0.5-20 cycles/degree). A contrast sensitivity function (CSF) was then fitted for each participant, from which four measures were obtained: visual acuity, peak spatial frequency, peak contrast sensitivity, and contrast sensitivity at a low spatial frequency. There were no group differences on any of the four CSF measures, indicating no differential spatial frequency processing in ASD. Although it has been suggested that detail-oriented visual perception in individuals with ASD may be a result of differential sensitivities to low versus high spatial frequencies, the current study finds no evidence to support this hypothesis
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