Convergent structure and function of mycelial galleries in two unrelated Neotropical plant-ants.

The construction process and use of galleries by Azteca brevis (Myrmicinae: Dolichoderinae) inhabiting Tetrathylacium macrophyllum (Salicaceae) were compared with Allomerus decemarticulatus (Myrmicinae: Solenopsidini) galleries on Hirtella physophora (Chrysobalanaceae). Though the two ant species are phylogenetically distant, the gallery structure seems to be surprisingly similar and structurally convergent: both are pierced with numerous holes and both ant species use Chaetothyrialean fungi to strengthen the gallery walls. Al. decemarticulatus is known to use the galleries for prey capture and whether this is also the case for Az. brevis was tested in field experiments. We placed Atta workers as potential prey/threat on the galleries and recorded the behaviour of both ant species. We found considerable behavioural differences between them: Al. decemarticulatus was quicker and more efficient at capture than was Az. brevis. While most Atta workers were captured after the first 5 min by Al. decemarticulatus, significantly fewer were captured by Az. brevis even after 20 min. Moreover, the captured Atta were sometimes simply discarded and not taken to the nest by Az. brevis. As a consequence, the major function of the galleries built by Az. brevis may, therefore, be defense against intruders in contrast to Al. decemarticulatus which uses them mainly for prey capture. This may be due to a higher need for protein in Al. decemarticulatus compared to coccid-raising Az. brevis.

Structure, transport and photoconductance of PbS quantum dot monolayers functionalized with a copper phthalocyanine derivative.

We simultaneously surface-functionalize PbS nanocrystals with Cu 4,4',4'',4'''-tetraaminophthalocyanine and assemble this hybrid material into macroscopic monolayers. Electron microscopy and X-ray scattering reveal a granular mesocrystalline structure with strong coherence between the atomic lattice and the superlattice of nanocrystals within each domain. Terahertz spectroscopy and field-effect transistor measurements indicate efficient coupling of holes throughout the hybrid thin film, in conjunction with a pronounced photoresponse. We demonstrate the potential of this material for optoelectronic applications by fabricating a light-effect transistor.

Topical anesthesia of the eye as a diagnostic test.

We investigated whether ocular response to topical anesthetic could assist the physician in distinguishing between patients with simple corneal injury and those with iritis, conjunctivitis, or other causes of acute eye pain. Seventy-one patients who presented to the emergency department filled out visual analog pain scores (range, 0 to 10) before and after use of topical anesthetic (proparacaine 0.5%). Mean initial pain scores were higher (6.3 +/- 3.0 vs 4.8 +/- 2.8, P less than .05), final pain scores were lower (1.1 +/- 1.7 vs 3.5 +/- 2.5, P less than .001), and changes in scores were greater (5.2 +/- 3.0 vs 1.3 +/- 1.3, P less than .001) in patients who had simple corneal injury compared with those who had other causes of acute eye pain. By defining response to topical anesthetic as a reduction in pain score by more than 5 (on a scale of 1 to 10) or as a final pain score of less than 1, we found the sensitivity of this test for simple corneal injury to be 80% and the specificity to be 86%. This information is useful to physicians, either with or without a slitlamp, attempting to diagnose the cause of acute eye pain.