A Prototype Apparatus for Determining Changes in the Electrical Conductivity of Production Run Carbon Fibers

During the production and processing of continuous lengths of carbon fibers (a tow), the conductivity along the length of the tow may vary significantly depending on the variation of the heat treatment temperature (HTT) and the resident furnace time. For PAN-type (polyacrylonitrile) fibers at HTT greater than 1000°C, a small change in HTT results in a large change in conductivity 03C3. For lower values of HTT, the corresponding change in σ can be quite small [1]

Alcohol-related brain damage in humans

Chronic excessive alcohol intoxications evoke cumulative damage to tissues and organs. We examined prefrontal cortex (Brodmann’s area (BA) 9) from 20 human alcoholics and 20 age, gender, and postmortem delay matched control subjects. H & E staining and light microscopy of prefrontal cortex tissue revealed a reduction in the levels of cytoskeleton surrounding the nuclei of cortical and subcortical neurons, and a disruption of subcortical neuron patterning in alcoholic subjects. BA 9 tissue homogenisation and one dimensional polyacrylamide gel electrophoresis (PAGE) proteomics of cytosolic proteins identified dramatic reductions in the protein levels of spectrin β II, and α- and β-tubulins in alcoholics, and these were validated and quantitated by Western blotting. We detected a significant increase in α-tubulin acetylation in alcoholics, a non-significant increase in isoaspartate protein damage, but a significant increase in protein isoaspartyl methyltransferase protein levels, the enzyme that triggers isoaspartate damage repair in vivo. There was also a significant reduction in proteasome activity in alcoholics. One dimensional PAGE of membrane-enriched fractions detected a reduction in β-spectrin protein levels, and a significant increase in transmembranous α3 (catalytic) subunit of the Na+,K+-ATPase in alcoholic subjects. However, control subjects retained stable oligomeric forms of α-subunit that were diminished in alcoholics. In alcoholics, significant loss of cytosolic α- and β-tubulins were also seen in caudate nucleus, hippocampus and cerebellum, but to different levels, indicative of brain regional susceptibility to alcohol-related damage. Collectively, these protein changes provide a molecular basis for some of the neuronal and behavioural abnormalities attributed to alcoholics

Influence du traitement thermique sur les propriétés de surface des fibres de carbone ex-mésophase

Les propriétés de surface de fibres de carbone préparées à partir d’un brai de pétrole à l’état de mésophase ont été étudiées en fonction de la température la plus haute de traitement thermique (HTT). La caractérisation des propriétés de surface a été réalisée par ESCA, ASA et chromatographie gazeuse inverse. Nos résultats montrent que la surface des fibres présente des plans de base ayant une tendance élevée aux interactions dispersives. Lorsque l’on passe de la température de carbonisation à la température de graphitisation, l’organisation en plans de base parallèles à la surface s’accroît et le nombre d’atomes de bordure émergents à la surface décroit avec HTT, ainsi que le nombre d’atomes d’oxygène qui leur sont liés. L’aptitude des fibres à échanger des actions spécifiques superficielles est proportionnelle à la teneur en atomes d’oxygène fixés à la surface. L’élévation de HTT diminue davantage le caractère acide que le caractère basique superficiel, enfin l’aptitude des surfaces de fibre de carbone à échanger des interactions dispersives ne doit pas être négligée lors de la caractérisation de l’adhésion fibre- matrice