Chemical milling solution produces smooth surface finish on aluminum

Elementary sulfur mixed into a solution of caustic soda and salts produces an etchant which will chemically mill end-grain surfaces on aluminum plate. This composition results in the least amount of thickness variation and pitting

Bacillary angiomatosis in HIV-infected patients - An epidemiological and clinical study

Background: No data were available on the epidemiological and clinical characteristics of bacillary angiomatosis (BA) in Germany. Objective:To determine epidemiological and clinical data on HIV-associated BA. Methods: A chart review of all BA cases between 1990 and 1998 was performed in 23 German AIDS treatment units. Results: A total of 21 cases of BA was diagnosed. During th is period, the participating HIV centers treated about 17,000 HIV-infected patients. As a result, a BA prevalence of 1.2 cases/1,000 patients can be assumed. 19 BA were localized in the skin; in 5 cases bones and in 4 cases the liver were involved. Out of 20 patients who received antibiotic therapy, 13 had complete remission. The median time of duration up to complete remission was 32 days (9-82), During the follow-up of the 20 patients, 7 relapses were observed, Conclusion: BA is a rare HIV-associated disease with a prevalence of 1,2 cases/1,000 patients in the presented study. Copyright (C) 2000 S. Karger AG, Basel

Insect-Habitat Relationships in Intermittent Streams of Eastern South Dakota

Relationships between habitat and invertebrate community structure are an important aspect of bioassessment. Little effort has been made to address these relationships in intermittent streams. The objective of this effort was to examine relationships between habitat and insect community metrics in intermittent streams in Eastern South Dakota. Habitat parameters were measured at 21 sites August 2001 and April, June and August 2002. Aquatic insect samples were collected from all sites, August through October 2001 and April through September 2002. Spearman rank correlation analysis was performed on mean site values (n=21) for habitat and insect community metrics. Only significant correlations (p\u3c0.05) are reported here. Several invertebrate metrics were positively correlated with substrate, bank, and flow measurements. Percent Chironomidae and sprawlers were associated with percent unstable substrate (rho = 0.41 and 0.45, respectively) while percent Ephemeroptera plus Trichoptera were positively associated with fine gravel (rho = 0.47). Numbers of filterers were associated with greater bank erosion, undercut banks and stream flow (rho = 0.42, 0.60 and 0.90, respectively). In contrast, percent Diptera and Trichoptera and Ephemeroptera richness were negatively associated with emergent vegetation (rho = -0.46 to -0.50) and percent predators were negatively associated with stream flow and percent bank erosion (rho = -0.58, -0.73, respectively). These results demonstrate strong relationships between insect community composition, richness and guild metrics and habitat characteristics which may facilitate bioassessment of intermittent streams in Eastern South Dakota

Residual Symmetries in the Spectrum of Periodically Driven Alkali Rydberg States

We identify a fundamental structure in the spectrum of microwave driven alkali Rydberg states, which highlights the remnants of the Coulomb symmetry in the presence of a non-hydrogenic core. Core-induced corrections with respect to the hydrogen spectrum can be accounted for by a perturbative approach.Comment: 7 pages, 2 figures, to be published in Europhysics Letter