Gamma irradiation effect on photocatalytic properties of Cu and Sr ions codoped PbS.

Gamma-irradiation effects on photocatalytic action of PbS nanocrystallites codoped with Cu and Sr ions were performed for organic dye degradation. The physical and chemical characterizations of these nanocrystallites were examined employing X-ray diffraction, Raman, and field emission electron microscopic analysis. The optical bandgaps of gamma-irradiated PbS with co-dopants have shifted from 1.95 eV (pristine PbS) to 2.45 eV in the visible spectrum. Under direct sunlight, the photocatalytic action of these compounds against methylene blue (MB) was investigated. Observations indicated that gamma-irradiated Pb(0.98)Cu0.01Sr0.01S nanocrystallite sample exhibits a higher photocatalytic degradation activity of 74.02% in 160 min and stability of 69.4% after three cycles, suggesting that gamma irradiation could potentially influence organic MB degradation. This is due to combined action of high-energy gamma irradiation (at an optimzed dose), which causes sulphur vacancies, and defects created by dopant ions, which alter the crystal structure by inducing strain in the crystal lattice, hence altering the crystallinity of PbS.

Global Gene Expression Analysis in PKCα-/- Mouse Skin Reveals Structural Changes in the Dermis and Defective Wound Granulation Tissue.

The skin's mechanical integrity is maintained by an organized and robust dermal extracellular matrix (ECM). Resistance to mechanical disruption hinges primarily on homeostasis of the dermal collagen fibril architecture, which is regulated, at least in part, by members of the small leucine-rich proteoglycan (SLRP) family. Here we present data linking protein kinase C alpha (PKCα) to the regulated expression of multiple ECM components including SLRPs. Global microarray profiling reveals deficiencies in ECM gene expression in PKCα-/- skin correlating with abnormal collagen fibril morphology, disorganized dermal architecture, and reduced skin strength. Detailed analysis of the skin and wounds from wild-type and PKCα-/- mice reveals a failure to upregulate collagen and other ECM components in response to injury, resulting in delayed granulation tissue deposition in PKCα-/- wounds. Thus, our data reveal a previously unappreciated role for PKCα in the regulation of ECM structure and deposition during skin wound healing.