Most of the normal human airway is lined by a pseudostratified epithelium of ciliated cells, secretory cells and 6-30% basal cells, the proportion of which varies along
the proximal-distal axis. Epithelial abnormalities range from hypoplasia (failure to differentiate) to basal-and goblet-cell hyperplasia, squamous-and Fer-1 cell line goblet-cell metaplasia, dysplasia and malignant transformation. Mesenchymal alterations include thickening of the basal lamina, smooth muscle hyperplasia, fibrosis and inflammatory cell accumulation. Paradoxically, given the prevalence and importance of airway remodeling in lung disease, its etiology is poorly understood. This is due, in part, to a lack of basic knowledge of the mechanisms that regulate the differentiation, maintenance
and repair of the airway epithelium. Specifically, selleck inhibitor little is known about the proliferation and differentiation of basal cells, a multipotent stem cell population of the pseudostratified airway epithelium. This Perspective summarizes what we know, and what we need to know, about airway basal cells to evaluate their contributions to normal and abnormal airway remodeling. We contend that exploiting well-described model systems using both human airway epithelial cells and the pseudostratified epithelium of the genetically tractable mouse trachea will enable crucial discoveries regarding the pathogenesis of airway disease.”
“An environmental-friendly approach called high-shear mechanical milling was developed to de-crosslink ground tire rubber (GTR) and waste crosslinked polyethylene (XLPE). The realization of partial devulcanization of GTR and de-crosslinking of XLPE were confirmed by gel fraction measurements. Fourier transform ALK inhibitor cancer infrared spectral studies revealed that a new peak at 1723.3 cm(-1) corresponds to the carbonyl group (-C=O) absorption was appeared after milling. The rheological properties showed that the XLPE/GTR blends represent lower apparent viscosity after mechanical milling, which means that the milled blends
are easy to process. Thermoplastic vulcanizates (TPVs) could be prepared with these partially de-crosslinked XLPE/GTR composite powders through dynamic vulcanization. The mechanical properties of the XLPE/GTR composites increased with increasing cycles of milling. The raw XLPE/GTR blends could not be processed to a continuous sheet. After 20 cycles of milling, the tensile strength and elongation at break of XLPE/GTR (50/50) composites increased to 6.0 MPa and 185.3%, respectively. The tensile strength and elongation at break of the composites have been further improved to 9.1 MPa and 201.2% after dynamic vulcanization, respectively. Re-processability study confirmed the good thermoplastic processability of the TPVs prepared. (C) 2011 Wiley Periodicals, Inc.