Maps of residual bathymetry in the ocean basins around the African continent reveal a broad bathymetric swell in the southeastern Atlantic Ocean with an amplitude of about 500m. We propose that this region of anomalously shallow bathymetry, together with the contiguous eastern and southern African plateaus, form a superswell which we refer to as the African superswell. The origin of the African superswell is uncertain. However, rifting and volcanism in eastern Africa, as well as heat flow measurements in southern Africa and the southeastern Atlantic Ocean, suggest that the superswell may be attributed, at least in part, to heating of the lithosphere.

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Nitric oxide (NO.) sensors were prepared using o-phenylenediamine (o-PD) and Nafion to modify the surface of 30 microns diameter carbon fiber electrodes. These electrodes were compared with nickel porphyrin-type NO. sensors that have already been described. High-speed chronoamperometry, amperometry, and differential pulse voltammetry were used to compare the performance of sensors modified with various combinations of Nafion, o-PD, or nickel(II) meso-tetrakis(3-methoxy-4-hydroxyphenyl) porphyrin (Ni-TMPP), in order to determine which electrodes had the most sensitivity and selectivity for NO. Our findings showed that electrodes treated with Nafion first, followed by o-PD, were very sensitive to NO., with a detection limit of 35 +/- 7 nM. In addition, o-PD electrodes were also very selective against ascorbate (> 600:1), dopamine (> 300:1), and nitrite (> 900:1). Moreover, in the range of 0-6 microM NO., o-PD electrodes displayed excellent linearity (R2 > or = 0.997). In contrast, Ni-TMPP electrodes (with Nafion) had significantly poorer detection limits (76 +/- 12 nM) and were less selective against dopamine (< 5:1) and nitrite (< 200:1). Ni-TMPP electrodes were also less linear than o-PD electrodes (R2 > or = 0.911). Finally, we tested the in vitro and in vivo performance of the o-PD electrode in terms of its ability to detect NO. release from isolated rat renal arterioles and to measure NO. diffusion in the extracellular space of the rat brain.

The FlyAtlas resource contains data on the expression of the genes of Drosophila melanogaster in different tissues (currently 25—17 adult and 8 larval) obtained by hybridization of messenger RNA to Affymetrix Drosophila Genome 2 microarrays. The microarray probe sets cover 13 250 Drosophila genes, detecting 12 533 in an unambiguous manner. The data underlying the original web application (http://flyatlas.org) have been restructured into a relational database and a Java servlet written to provide a new web interface, FlyAtlas 2 (http://flyatlas.gla.ac.uk/), which allows several additional queries. Users can retrieve data for individual genes or for groups of genes belonging to the same or related ontological categories. Assistance in selecting valid search terms is provided by an Ajax ‘autosuggest’ facility that polls the database as the user types. Searches can also focus on particular tissues, and data can be retrieved for the most highly expressed genes, for genes of a particular category with above-average expression or for genes with the greatest difference in expression between the larval and adult stages. A novel facility allows the database to be queried with a specific gene to find other genes with a similar pattern of expression across the different tissues.

Pseudovoltammetry was used to evaluate the actual Pb complexation occurring in natural water samples of varying oxygen and sulfide concentration. In pseudovoltammetry, the potential at which metal-ligand complexes are broken up to form the metal amalgam is used to determine the complexes' thermodynamic stability constants (KTHERM; corrected for metal and ligand side reaction coefficients) via the Nernst expression. This methodology removes the need for any metal additions and for subsequent modeling using fitting criteria, which provide only conditional stability constant data (KCOND). Using known organic ligands, a chelate scale ranging from log KTHERM = 4 to log KTHERM = 20 was developed as a template for comparison with samples collected from two stations of different salinities and at several depths in the Chesapeake Bay. These samples were observed to contain up to five different ligand compounds of unknown structural composition (log KTHERM > 8) with the strongest ligand fraction exceeding log KTHERM > 39 (the maximum observable thermodynamic stability constant due to the reduction of Na+). One possible explanation for the observed complexation is the existence of lead sulfide clusters. This was supported by laboratory experiments using electrochemistry and ICR-FTMS, which confirmed the formation of electrochemically inert multinuclear clusters with high stability constants (e.g., M3S3, log KTHERM = 62.9). However, in all field samples, (sub)nanomolar levels of acid-leachable sulfide were recovered at pH 5.0-6.2, which could be attributed to dissociation of lead sulfide complexes with moderate acidity. Recovery of sulfide increased from < 10% of the total dissolved Pb concentration (Pbdiss) in surface waters to 100% of the Pbdiss in the sulfide-rich bottom waters at the higher salinity location.