Microwave graph analogs for the voltage drop in three-terminal devices with orthogonal, unitary, and symplectic symmetry.

Transmission measurements through three-port microwave graphs are performed, in analogy to three-terminal voltage drop devices with orthogonal, unitary, and symplectic symmetry. The terminal used as a probe is symmetrically located between two chaotic subgraphs, and each graph is connected to one port, the input and the output, respectively. The analysis of the experimental data clearly exhibits the weak localization and antilocalization phenomena. We find a good agreement with theoretical predictions, provided that the effects of dissipation and imperfect coupling to the ports are taken into account.

Short term inhalation toxicity of a liquid aerosol of glutaraldehyde-coated CdS/Cd(OH)2 core shell quantum dots in rats.

Quantum dots exhibit extraordinary optical and mechanical properties, and the number of their applications is increasing. In order to investigate a possible effect of coating on the inhalation toxicity of previously tested non-coated CdS/Cd(OH)2 quantum dots and translocation of these very small particles from the lungs, rats were exposed to coated quantum dots or CdCl2 aerosol (since Cd(2+) was present as impurity), 6h/d for 5 consecutive days. Cd content was determined in organs and excreta after the end of exposure and three weeks thereafter. Toxicity was determined by examination of broncho-alveolar lavage fluid and microscopic evaluation of the entire respiratory tract. There was no evidence for translocation of particles from the respiratory tract. Evidence of a minimal inflammatory process was observed by examination of broncho-alveolar lavage fluid. Microscopically, minimal to mild epithelial alteration was seen in the larynx. The effects observed with coated quantum dots, non-coated quantum dots and CdCl2 were comparable, indicating that quantum dots elicited no significant effects beyond the toxicity of the Cd(2+) ion itself. Compared to other compounds with larger particle size tested at similarly low concentrations, quantum dots caused much less pronounced toxicological effects. Therefore, the present data show that small particle sizes with corresponding high surfaces are not the only factor triggering the toxic response or translocation.

Biodiversity of Asterina species on Neotropical host plants: new species and records from Panama.

Two new species of the genus Asterina are described from living leaves collected in provinces Chiriquí and Bocas del Toro in western Panama. Asterina alloplecti on Alloplectus ichtyoderma (Gesneriaceae) differs from other Asterina on Gesneriaceae by its stalked appressoria and host relationship. Asterina compsoneurae on Compsoneura sprucei (Myristicaceae) can be distinguished from other members of Asterina on Myristicaceae by its larger ascomata, larger, prominently spinose ascospores and host relationship. New records for Panama are Asterina corallopoda from a new host plant species (Solanum trizygum, Solanaceae), A. diplopoda, A. ekmanii from a new host plant species (Gonzalagunia rudis, Rubiaceae), A. siphocampyli from a new host plant genus and species (Burmeistera vulgaris, Campanulaceae) and A. styracina from a new host-plant species (Styrax argenteus, Styracaceae). This study increases the number of species of Asterina known for Panama from 12 to 19 and the number of Asterinaceae from 14 to 21. Asterina corallopoda, A. diplopoda, A. ekmanii, A. siphocampyli and A. styracina are illustrated for the first time. A phylogeny inferred from the analysis of LSU rDNA sequences of species of Asterina is presented. The diversity and host-plant patterns of known Neotropical species of Asterina are discussed.