Characterization of Photo-Crosslinked Methacrylated Type I Collagen as a Platform to Investigate the Lymphatic Endothelial Cell Response.

Despite chronic fibrosis occurring in many pathological conditions, few in vitro studies examine how fibrosis impacts lymphatic endothelial cell (LEC) behavior. This study examined stiffening profiles of PhotoCol-commercially available methacrylated type I collagen-photo-crosslinked with the photoinitiators: Lithium phenyl-2,4,6-trimethylbenzoylphosphinate (LAP), Irgacure 2959 (IRG), and Ruthenium/Sodium Persulfate (Ru/SPS) prior to evaluating PhotoCol permeability and LEC response to PhotoCol at stiffnesses representing normal and fibrotic tissues. Ru/SPS produced the highest stiffness (~6 kilopascal (kPa)) for photo-crosslinked PhotoCol, but stiffness did not change with burst light exposures (30 and 90 s).

Convergent Evolution of Pregnancy in Vertebrates.

Viviparity (live birth) represents a significant evolutionary innovation that has emerged in hundreds of lineages of invertebrate and vertebrate animals. The evolution of this trait from the ancestral state of egg laying has involved complex morphological, behavioral, physiological, and genetic changes, which enable internal development of embryos within the female reproductive tract. Comparable changes have also occurred in oviparous, brooding species that carry developing embryos in locations other than the female reproductive tract.

The logic of conventional and reversed Bateman gradients.

The Bateman gradient is a central concept in sexual selection theory that relates reproductive success to mate number, with important consequences for sex-specific selection. The conventional expectation is that Bateman gradients are steeper in males than females, implying that males benefit more from multiple mating than females do. This claim is supported by much empirical evidence as well as mathematical modelling.