2,451 research outputs found
Cardiac stem cells: A promising treatment option for heart failure.
Cardiovascular diseases are the most common cause of death in the world. The development of heart failure is mainly due to the loss of cardiomyocytes following myocardial infarction and the absence of endogenous myocardial repair. Numerous studies have focused on cardiac stem cells (CSCs) due to their therapeutic benefit, particularly in the treatment of heart failure. It has previously been demonstrated that CSCs are able to promote the regeneration of cardiomyocytes in animals following myocardial infarction. However, the underlying mechanism(s) remain unclear. This review mainly discusses the cardioprotective effect of CSCs and the effect of CSCs on the function of cardiomyocytes, and compares the efficacies of CSCs from rats, mice and humans, thereby contributing to an improved understanding of CSCs as a promising treatment option for heart failure
Development of long range cation order and its impact on dielectric properties in Pb(Mg1/3Nb2/3)O3 based relaxor ferroelectrics
As the prototype of relaxor ferroelectrics, Pb(Mg1/3Nb2/3)O3 (PMN) has been extensively investigated for several decades. There are two types of microscopic features in PMN: cation order and electric dipole order. The development of long range cation order in PMN has proved to be challenging and the relationship between these two types of order is still open for debate. In this work, different kinds of cations and/or defects were introduced into Pb(Mg1/3Nb2/3)O3 to develop long range cation order. The impact of the enhanced cation order on the dielectric properties of Pb(Mg1/3Nb2/3)O3-based ceramics was systematically investigated. Ceramic samples were prepared via the columbite method to ensure phase purity. High temperature thermal treatments were used to manipulate the degree of cation order of the material. Dielectric and ferroelectric properties, including relative permittivity, thermal depolarization current and polarization vs. electric field hysteresis, were measured. It was shown that the cation order in these relaxor ceramics was significantly enhanced. However, different dielectric and ferroelectric properties were observed in these perovskite materials. The difference was interpreted in terms of size/charge mismatch of two B-site sublattices and size/charge difference between them. The electric field--temperature phase diagrams of PMN-based ceramics and PMN single crystals were also constructed based on electric field-induced phase transitions
A Stochastic Frontier Model for Discrete Ordinal Outcomes: A Health Production Function
The stochastic frontier model used for continuous dependent variables is extended to accommodate output measured as a discrete ordinal outcome variable. Conditional on the inefficiency error, the assumptions of the ordered probit model are adopted for the log of output. Bayesian estimation utilizing a Gibbs sampler with data augmentation is applied to a convenient re-parameterisation of the model. Using panel data from an Australian longitudinal survey, demographic and socioeconomic characteristics are specified as inputs to health production, whereas production efficiency is made dependent on lifestyle factors. Posterior summary statistics are obtained for selected health status probabilities, efficiencies, and marginal effects.Bayesian estimation, Gibbs sampling, ordered probit, production efficiency.
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