This study demonstrates translocation of adventitial fibroblasts to neointima, their phenotypic modulation to myofibroblasts, and distinct characteristics of myofibroblasts within neointima after severe endoluminal coronary injury. These findings suggest the significance of vascular fibroblasts in the process of arterial repair.
This study demonstrates the involvement of the adventitia in the vascular repair process after medial injury. The hypercellularity of the adventitial layer, proliferation of fibroblasts, and modulation of their phenotype to myofibroblasts are associated with the development of the thickened adventitia. It is postulated that these phenomena affect vascular remodeling and may provide an important insight into the mechanisms of vascular disorders.
A research program is under way at the Idaho National Laboratory to assess the performance of solid-oxide cells operating in the steam electrolysis mode for hydrogen production over a temperature range of 800 to 900ºC. The research program includes both experimental and modeling activities. Selected results from both activities are presented in this paper. Experimental results were obtained from a ten-cell planar electrolysis stack, fabricated by Ceramatec 1 , Inc. The electrolysis cells are electrolyte-supported, with scandiastabilized zirconia electrolytes (~140 µm thick), nickel-cermet steam/hydrogen electrodes, and manganite air-side electrodes. The metallic interconnect plates are fabricated from ferritic stainless steel. The experiments were performed over a range of steam inlet mole fractions (0.1 -0.6), gas flow rates (1000 -4000 sccm), and current densities (0 to 0.38 A/cm 2 ). Hydrogen production rates up to 90 Normal liters per hour were demonstrated. Stack performance is shown to be dependent on inlet steam flow rate. A three-dimensional computational fluid dynamics (CFD) model was also created to model high-temperature steam electrolysis in a planar solid oxide electrolysis cell (SOEC). The model represents a single cell as it would exist in the experimental electrolysis stack. Mass, momentum, energy, and species conservation and transport are provided via the core features of the commercial CFD code FLUENT 1 . A solid-oxide fuel cell (SOFC) model adds the electrochemical reactions and loss mechanisms and computation of the electric field throughout the cell. The FLUENT SOFC user-defined subroutine was modified for this work to allow for operation in the SOEC mode. Model results provide detailed profiles of temperature, Nernst potential, operating potential, anode-side gas composition, cathode-side gas composition, current density and hydrogen production over a range of stack operating conditions. Mean model results are shown to compare favorably with the experimental results obtained from the ten-cell stack tested at INL.
Background-The importance of noncoding RNAs (ncRNA), especially microRNAs (miRNAs), for maintaining stability in the developing vertebrate heart has recently become apparent; however, there is little known about the expression pattern of ncRNA in the human heart with developmental anomalies. Methods and Results-We examined the expression of miRNAs and small nucleolar RNAs (snoRNAs) in right ventricular myocardium from 16 infants with nonsyndromic tetralogy of Fallot (TOF) without a 22q11.2 deletion, 3 fetal heart samples, and 8 normally developing infants. We found 61 miRNAs and 135 snoRNAs to be significantly changed in expression in myocardium from children with TOF compared with normally developing comparison subjects. The pattern of ncRNA expression in TOF myocardium had a surprising resemblance to expression patterns in fetal myocardium, especially for the snoRNAs. Potential targets of miRNAs with altered expression were enriched for gene networks of importance to cardiac development. We derived a list of 229 genes known to be critical to heart development and found 44 had significantly changed expression in TOF myocardium relative to normally developing myocardium. These 44 genes had significant negative correlation with 33 miRNAs, each of which also had significantly changed expression. The primary function of snoRNAs is targeting specific nucleotides of ribosomal RNAs and spliceosomal RNAs for biochemical modification. The targeted nucleotides of the differentially expressed snoRNAs were concentrated in the 28S and 18S ribosomal RNAs and 2 spliceosomal RNAs, U2 and U6. In addition, in myocardium from children with TOF, we observed splicing variants in 51% of genes that are critical for cardiac development. Taken together, these observations suggest a link between levels of snoRNA that target spliceosomal RNAs, spliceosomal function, and heart development. Conclusions-This is the first report characterizing ncRNA expression in a congenital heart defect. The striking shift in expression of ncRNAs reflects a fundamental change in cell biology, likely impacting expression, transcript splicing, and translation of developmentally important genes and possibly contributing to the cardiac defect. (Circ Cardiovasc Genet. 2012;5:279-286.)Key Words: tetralogy of Fallot Ⅲ cardiac development Ⅲ microRNA Ⅲ miRNA Ⅲ small nucleolar RNA Ⅲ snoRNA T he heart is the first major internal organ to form during embryogenesis, and it is critical for the viability of the embryo. A multitude of genes and genetic networks contribute to the spatial and temporal specification of cell lineage required for proper embryological heart formation. 1 Failure of proper cellular differentiation, migration, and apoptosis results in congenital heart defects (CHD), which are a major cause of childhood morbidity and mortality and remains a substantial challenge even in countries with advanced healthcare systems. The incidence of CHD is approximately 8 per 1000 live births, 2 making CHD the most common birth defect. Mendelian and chromosomal syndro...
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.