Xirp Proteins Mark Injured Skeletal Muscle in Zebrafish

Myocellular regeneration in vertebrates involves the proliferation of activated progenitor or dedifferentiated myogenic cells that have the potential to replenish lost tissue. In comparison little is known about cellular repair mechanisms within myocellular tissue in response to small injuries caused by biomechanical or cellular stress. Using a microarray analysis for genes upregulated upon myocellular injury, we identified zebrafish Xin-actin-binding repeat-containing protein1 (Xirp1) as a marker for wounded skeletal muscle cells. By combining laser-induced micro-injury with proliferation analyses, we found that Xirp1 and Xirp2a localize to nascent myofibrils within wounded skeletal muscle cells and that the repair of injuries does not involve cell proliferation or Pax7+ cells. Through the use of Xirp1 and Xirp2a as markers, myocellular injury can now be detected, even though functional studies indicate that these proteins are not essential in this process. Previous work in chicken has implicated Xirps in cardiac looping morphogenesis. However, we found that zebrafish cardiac morphogenesis is normal in the absence of Xirp expression, and animals deficient for cardiac Xirp expression are adult viable. Although the functional involvement of Xirps in developmental and repair processes currently remains enigmatic, our findings demonstrate that skeletal muscle harbours a rapid, cell-proliferation-independent response to injury which has now become accessible to detailed molecular and cellular characterizations

CORE PHOTOELECTRON-SPECTRA OF NARROW-BAND METALLIC MATERIALS

Complex core level structure is encountered in the photoelectron spectra of a wide range of narrow-band metallic oxides. The examples cited include cases where the metal atom is in an integral, formal oxidation state. The observations lend support to the view that multi-peak structure in the core photoelectron spectra of the cubic tungsten bronzes should be interpreted in terms of final-state effects rather than valence localisation in the neutral system. © 1980

A comparison of measured fission gas releases for Windscale AGR fuel irradiated above 18 GWd/tU with those predicted using the computer code MINIPAT D

2.00SIGLELD:9091.0F(ND-R--803(W)) / BLDSC - British Library Document Supply CentreGBUnited Kingdo

A Photoelectron Spectroscopy Study of Stoichiometric and Reduced Anatase TiO2 (101) Surfaces: The Effect of Subsurface Defects on Water Adsorption at Near-Ambient Pressures

X-ray photoelectron (XPS) experiments at normal and grazing emission are performed, demonstrating the labile nature of the anatase TiO₂(101) surface after argon cluster ion sputtering and the propensity of oxygen vacancies to migrate subsurface at room temperature. Near-ambient XPS (NAP-XPS) shows that molecular water adsorbs on the anatase TiO₂(101) surface at pressures of 0.6 mbar and above, at room temperature, in a mixed molecular and dissociated state. Water adsorbs in a similar fashion on both sputtered and stoichiometric surfaces and reaches a saturation point between 0.6 and 1.8 mbar at room temperature. This means there is little difference in reactivity with regards to water adsorption on both sputtered and stoichiometric surfaces, giving credence to the theory that anatase has superior photocatalytic activity over rutile due to the tendency of oxygen vacancies to lie subsurface, therefore being able to contribute to photocatalysis without being quenched by adsorbates