Impaired protein synthesis (PS) occurs in skeletal muscle during acute starvation. Even though it is well established that uraemic metabolic acidosis (MA) stimulates protein degradation (PD) and is a major contributor to skeletal muscle wasting in chronic renal failure, the accompanying effects of MA on PS are much less clear. Previous work has shown that, in cultured L6 skeletal muscle cells, PD and leucine oxidation are stimulated by acid. The aim of the present study was to determine whether acid (like acute starvation) can also inhibit PS. PS (¹⁴C-phenylalanine incorporation) was measured in L6 cells in MEM + 2% serum at acid pH (7.1) or control pH (7.5). After 24 h, acid inhibited PS (7.7 ± 0.2 vs. 8.9 ± 0.1 nmol Phe/4 h/35-mm culture well in controls, p = 0.01) and this was maintained at 72 h. In vitro this could arise because acid only inhibits the rapid PS occurring in dividing cells. However, when division was abolished with 10^–5 mol/l cytosine arabinoside, PS inhibition by acid still occurred (6.9 ± 0.1 vs. 8.3 ± 0.2 at control pH, p < 0.05). Acid also had no effect on the specific radioactivity of cellular phenylalanine, suggesting that the impaired PS was not a consequence of inadequate labelling of this pool. Elevated PD and impaired PS together led to loss of 7% of the total protein in only 28 h (–21 ± 3 µg/well, p = 0.004). This combination of impaired PS with increased PD and increased leucine oxidation in response to acid resembles the response of skeletal muscle to acute starvation. These superficial similarities between the starvation state and MA suggest that fundamental metabolic signals may occur which are common to both states.

In this work we describe thickness measurements from oxide layers on uranium and tantalum using Energy Dispersive Spectroscopy (EDS) combined with Oxford Instruments software calculating the layer thickness from measured X-ray intensities. A comparison of the oxide distribution is shown between (1) a user standardised system with an older SDD detector and INCA ThinFilmID and (2) the latest large area SDD detector and the AZtec LayerProbe software using built in standards (i.e. standardless analysis). As system (2) contains significantly improved routines for standardless analysis and better integration with the X-ray acquisition software it reduces the analysis time significantly over system (1).There is general agreement that the presence of the oxide film on uranium metal mediates its interaction with hydrogen [1] . Consequently, models of the initial stages of the uranium-hydrogen reaction have been developed in terms of the hydrogen transport properties and thickness distribution of this surface o x i d e [2] . For the purposes of validation or quantification of such models, therefore, it is essential to have a good understanding of the way in which oxide films grow on this metal (as a function of oxidising conditions) and how the mean oxide thickness (and later thickness distribution) depends on both oxidising conditions and exposure time.A Tantalum pentoxide standard BCR  261T certified by the Institute for Reference Materials and Measurements (IRMM) was used to provide a oxide thickness reference to test both the user standardised system running ThinFilmID and the AZtec LayerProbe system using built-in standards. Ta2O5 was chosen over other metal oxides as it is available commercially as a well characterised heavy element oxide standard. Composition and estimated thickness values for the tantalum pentoxide and uranium dioxide samples were entered into the ThinFilmID and LayerProbe set-up files and using this data the optimum analysis conditions were deduced from calculations of the relative statistical variation at different beam voltages (kV) [3] . The intensity of the Oxygen line O-Kα at 0.52eV was used to calculate the oxide thickness.On both systems measurement of the Si Κα signal at 1.740 keV from a bulk pure element standard of Si was used as a reference to normalise the X-ray count from the thin film samples and obtain measurements independent of beam current. For INCA ThinFilmID accuracy was improved by taking additional measurements on standards, again referenced to a measurement on the pure Si standard at the same beam energy. For AZtec LayerProbe, the factory default calibration was used. The results of the thickness measurements on the Ta 2 O 5 standard (Table 1) show that system (1) and system (2) give essentially the same results which validates the improvements made to standardless analysis accuracy in AZtec LayerProbe Our comparative study shows AZtec LayerProbe as a viable technique to measure the 1836

We report experiments in which powder-diffraction data were recorded from polycrystalline vanadium foils, shock-compressed to pressures in the range of 10–70 GPa. Anisotropic strain in the compressed material is inferred from the asymmetry of Debye-Scherrer diffraction images and used to infer residual strain and yield strength (residual von Mises stress) of the vanadium sample material. We find residual anisotropic strain corresponding to yield strength in the range of 1.2 GPa–1.8 GPa for shock pressures below 30 GPa, but significantly less anisotropy of strain in the range of shock pressures above this. This is in contrast to our simulations of the experimental data using a multi-scale crystal plasticity strength model, where a significant yield strength persists up to the highest pressures we access in the experiment. Possible mechanisms that could contribute to the dynamic response of vanadium that we observe for shock pressures ≥30 GPa are discussed.

We report the measurements of in situ Debye–Scherrer x-ray diffraction from copper foils shock compressed at the Orion laser facility to pressure in the range of 10–40 GPa. Our objective was to record distortion (variation of scattering angle at peak intensity, 2θ, with azimuthal position, φ, around the diffraction ring) of the Debye–Scherrer rings. We intended to measure the anisotropy of elastic strain and infer the effective strength of copper at a high strain rate. However, our measured diffraction data from all crystallographic reflection planes considered together are not consistent with a simple model that assumes homogeneous elastic strain. Consideration of both the β-fiber metallurgical texture of the rolled copper foil that we used as the sample material and the measured diffraction linewidths provides an empirical understanding of the data. We extend our understanding by using a Taylor-type, single-crystal plasticity model in which the total strain of each grain is assumed to be identical to that of the whole sample. This model reproduces many features of our experimental data and points to the importance of accounting for the plastic anisotropy of single-crystal grains, which can, in turn, lead to inter-grain elastic strain inhomogeneity and complex distortions of the diffraction rings.

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