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Objectives: Comparison of coronary artery stent assessment with cardiac CT angiography (cCTA) using traditional filtered back projection (FBP) and sinogram affirmed iterative reconstruction (SAFIRE), in both full- and half-radiation dose image data.Methods: Dual-source cCTA studies of 37 implanted stents were reconstructed at full- and half-radiation dose with FBP and SAFIRE. Half-dose data were based on projections from one DSCT detector. In-stent noise, signal-to-noise ratio (SNR), and stent-lumen attenuation increase ratio (SAIR) were measured and image quality graded. Stent volumes were measured to gauge severity of beam hardening artefacts.Results: Full-dose SAFIRE reconstructions were superior to full-dose FBP vis-à-vis in-stent noise (21.2 ± 6.6 vs. 35.7 ± 17.5; P < 0.05), SNR (22.1 ± 8.6 vs. 14.3 ± 6.7; P < 0.05), SAIR (19.6 ± 17.6 vs. 33.4 ± 20.4%; P < 0.05), and image quality (4.2 ± 0.86 vs. 3.5 ± 1.0; P < 0.05). Stent volumes were lower measured with SAFIRE (119.9 ± 53.7 vs. 129.8 ± 65.0 mm(3); P > 0.05). Comparing half-dose SAFIRE with full-dose FBP, in-stent noise (26.7 ± 13.0 vs. 35.7 ± 17.5; P < 0.05) and SNR (18.2 ± 6.9 vs. 14.3 ± 6.7; P < 0.05) improved significantly. SAIR (31.6 ± 24.3 vs. 33.4 ± 20.4%; P > 0.05), stent volume (129.6 ± 57.3 vs. 129.8 ± 65.0 mm(3); P > 0.05), and image quality (3.5 ± 1.0 vs. 3.7 ± 1.1; P > 0.05) did not differ. Radiation dose decreased from 8.7 ± 5.2 to 4.3 ± 2.6 mSv.Conclusions: Iterative reconstruction significantly improves imaging of coronary artery stents by CT compared with FBP, even with half-radiation-dose data. [ABSTRACT FROM AUTHOR]

(1) In 1981 and 1982 male and female reproductive success of mainland and near- and distant-island populations of Centrosema virginianum and Opuntia stricta growing on two island and one mainland beach communities on the western coast of Florida were compared. (2) Pollen dispersal to neighbouring plants (which was used as an estimate of male reproductive success) was significantly reduced in both island populations of Centrosema relative to the mainland population. Pollen dispersal of Opuntia was significantly lower at the far island than at the near island. (3) Female reproductive success (estimated by fruit set) was significantly lower in Centrosema on the distant island than on the near island or mainland during 1981. Fruit set in Opuntia did not differ between the near and far island however, seeds per fruit were significantly lower on the far island both years. (4) Field experiments indicated significant pollinator limitation of fruit set for Centrosema growing on the far island in 1981, but not in 1982. On the far island in 1983, there was no significant difference in the number of seeds per fruit in naturally-pollinated and hand-crossed Opuntia flowers. (5) The differences between island and mainland pollinator communities and reproductive success that were found in plant communities separated by less than 10 km of water, suggest that pollinator limitation may be an important selective force on plant communities of distant, oceanic islands. [ABSTRACT FROM AUTHOR]

The decomposition of Malachite Green, CI Basic Green 4, by carbon arc light source has been studied in aqueous solution and on sulfoethyl and carboxymethyl ethers of cellulose. A mechanism for the photochemical decomposition has been proposed for both the solution and cellulose substrates. The decomposition products isolated from the aqueous solution studies included benzaphenone, 4-methylaminobenzophenone, 4-dimethylaminobenzophenone and p-dimethylaminophenol. Evidence for the formation of both ketones was also found in cellulose substrate reaction products. Chromatographic, infrared and mass spectra analyses were used to identify the decomposition products. The fact that the decomposition products were similar from both the solution and fiber substrate studies is taken as evidence for an analogous decomposition mechanism leading to their formation. The pKa of the anionic dye site on the fiber substrate directly influenced the fading rate of Malachite Green. [ABSTRACT FROM AUTHOR]