Culture conditions influence satellite cell activation and survival of single myofibers

Single myofiber isolation protocols allow to obtain an in vitro system in which the physical association between the myofiber and its stem cells, the satellite cells, is adequately preserved. This technique is an indispensable tool by which the muscle regeneration process can be recapitulated and studied in each specific phase, from satellite cell activation to proliferation, from differentiation to fusion. This study aims to clarify the effect of different culture conditions on single myofibers, their associated satellite cells, and the physiological behavior of the satellite cells upon long term culture. By direct observations of the cultures, we compared different experimental conditions and their effect on both satellite cell behavior and myofiber viability

Study of SiC fiber-matrix interaction in ultra-high temperature ceramics by transmission electron microscopy

In the last few years ISTEC activity has been focused on the development of toughened ultra-high temperature ceramics, in order to fill the gap of the low intrinsic fracture toughness of this class of materials. Toughness improvement from 3.5 to around 6 MPa.m1/2 has been achieved through the addition of SiC short fibers, by varying processing methods, sintering additives, thermal treatments and type of fiber. In turn, all these parameters affect fiber integrity and the matrix/fiber interface chemistry, ultimately affecting the mechanical properties. The aim of this study was to understand how the sintering additive or specific treatments on the fiber can control the interface fiber/matrix. Transmission electron microscopy was mainly used as fundamental technique for the characterization at nanoscale level of the fiber morphology and interface with the matrix. A comparison between the evolution of the Hi Nicalon fiber versus the Tyranno type in ZrB2 matrices is presented, evidencing that different thermal stability and chemical inertness may affect the local and global microstructure. Relevant mechanical properties are also reported and related to the microstructural feature