Description: Article describing the discovery of Vanadium and tracing the footsteps of the discoverers.

Description: Article describing Eugène Demarcay and his discovery of europium. The authors toured Paris, France, in search of locations important to Demarcay, providing the reader with maps and historical information regarding the sites.

Description: In this article, the authors report the effects of microwave irradiation on both unpurified and purified iron-catalyzed high-pressure disproportionation (HiPco)-grown single-walled carbon nanotubes (SWNTs) in ultrahigh vacuum. Under microwave irradiation, the authors observe that unpurified HiPco SWNTs quickly reach temperatures of approximately 1850 ºC. As a result, H2, H2O, CO, CO2, and CH4 gases are observed, and the Fe catalyst nanoparticles melt and coalesce into larger crystallites approximately four times their original diameter. In contrast, carbon black and purified HiPco SWNTs heat up to temperatures of 500-650 ºC. The authors propose that the significant heating of unpurified HiPco SWNTs is due to the Fe catalysts.

Description: In this article, the authors study the statistical properties of time distribution of seismicity in California by means of a new method of analysis, the diffusion entropy. The authors find that the distribution of time intervals between a large earthquake (the main shock of a given seismic sequence) and the next one does not obey Poisson statistics, as assumed by the current models. The authors prove that this distribution is an inverse power law with an exponent μ = 2.06 ± 0.01. The authors propose the long-range model, reproducing the main properties of the diffusion entropy and describing the seismic triggering mechanisms induced by large earthquakes.

Description: This article discusses symplastic continuity between companion cells and the translocation stream. Substantial symplastic continuity appears to exist between companion cells (CCs) and sieve elements of the phloem, which suggests that small solutes within the CC are subject to indiscriminate long-distance transport via the translocation stream. To test this hypothesis, the distributions of exotic and endogenous solutes synthesized in the CCs of minor veins were studied. Octopine, a charged molecule derived from arginine and pyruvate, was efficiently transported through the phloem but was also transferred in substantial amounts to the apoplast, and presumably other non-phloem compartments. The disaccharide galactinol also accumulated in non-phloem compartments, but long-distance transport was limited. Conversely, sucrose, raffinose, and especially stachyose demonstrated reduced accumulation and efficient transport out of the leaf. The authors conclude that small metabolites in the cytosol of CCs do enter the translocation stream indiscriminately but are also subject to distributive forces, such as nonselective and carrier-mediated membrane transport and symplastic dispersal, that may effectively clear a compound from the phloem or retain it for long-distance transport. A model is proposed in which the transport or oligosaccharides is an adaptive strategy to improve photoassimilate retention, and consequently translocation efficiency, the phloem.