23 research outputs found
Albedo and laser threshold of a diffusive Raman gain medium
The diffuse reflectance (albedo) and transmittance of a Raman random gain
medium are calculated via semi-analytic two-stream equations with
power-dependent coefficients. The results show good agreement with the
experimental data for barium nitrate powder. Both the Raman albedo AR and Raman
transmittance TR diverge at a critical gain gc, interpreted as the threshold
for diffusive Raman laser generation. However, the ratio TR/AR approaches a
finite limiting value dependent on particle scattering albedo v and scattering
asymmetry g. The dependence of the generation threshold on the scattering
parameters is analysed and the feedback effect of Fresnel reflection at the
gain boundaries evaluated. The addition of external mirrors, particularly at
the pumped surface, significantly reduces the threshold gain.Comment: 15 pages, 8 figure
Simple analytic form of the relativistic Thomson scattering spectrum
2.00SIGLELD:9091.9F(CLM-R--220). / BLDSC - British Library Document Supply CentreGBUnited Kingdo
Effect of Graded Doses of Cholecystokinin Octapeptide (CCK 8) on Pancreatic Enzyme Secretion in Man
Flow simulations for a glow discharge laser
8.00Available from British Library Document Supply Centre- DSC:9091.9F(CLM-R--288) / BLDSC - British Library Document Supply CentreSIGLEGBUnited Kingdo
High power CO2 lasers
Available from British Library Document Supply Centre- DSC:9091.9F(CLM-P--847) / BLDSC - British Library Document Supply CentreSIGLEGBUnited Kingdo
Effect of Invivo Administration of An Antibody to Epidermal Growth-Factor On the Rapid Increase in Dna-Synthesis Induced by Partial-Hepatectomy in the Rat
Recent reports indicate that transforming growth factor alpha (TGF-alpha) is produced within the fiver and acts as the natural ligand of the epidermal growth factor (EGF) receptor causing the EGF receptor down regulation and the hepatocyte proliferation observed after partial hepatectomy. The reported phenomenon that an antibody to EGF inhibits the regenerative response to partial hepatectomy was therefore re-investigated. The IgG fraction of an anti-rat EGF antibody was injected intravenously at the time of partial hepatectomy, and its effects on regenerative DNA synthesis were compared with those of non-immune IgG. Injection of IgG reduced the DNA synthetic response to partial hepatectomy, assessed 24 hours after resection by H-3-thymidine incorporation, but the effects of normal and anti-EGF IgG were not statistically different, despite the presence of excess anti-EGF IgG in the circulation throughout the experimental period. However, anti-EGF IgG could completely block the proliferative response of hepatocytes in culture to EGF. These results support the suggestion that EGF is not the major mediator of hepatocyte DNA synthesis in the early stages of liver regeneration