Since their discovery by Mandelbrot (The Fractal Geometry of Nature, Freeman, New York, 1977), fractals have experienced considerable success in quantifying the complex structure exhibited by many natural patterns and have captured the imaginations of scientists and artists alike. With ever-widening appeal, they have been referred to both as ‘‘fingerprints of nature’’ (Nature 399 (1999) 422) an...

Infrared internal reflection spectroscopy (IRS) was used to investigate chemical changes of enamel surface during in vitro remineralization. Specimens were demineralized and exposed either to calcium phosphate-fluoride solutions or to acidulated fluorophosphate. The former showed amorphous phosphate remineralization, and the latter showed surface precipitate interpreted to be calcium fluoride. ...

a Center of Plant, Soil Interaction and Natural Resources Biotechnology, Scientific and Biotechnological Bioresource Nucleus (BIOREN-UFRO), Avenida Francisco Salazar 01145, Universidad de La Frontera, Temuco, Chile b Laboratoire Sol et Environnement (LSE), Université de Loraine, Vandoeurve les Nancy cedex, France c UMR Université Paris VI et XII-CNRS-INRA-IRD), Campus AgroParisTech, Thiverval-G...

Analysis of substances involved in light-emitting reactions among bioluminescent coelenterates has revealed a pronounced uniformity in the structural features of initial reactants, i.e., "luciferins" and photo-protein chromophores, as well as the light-emitter product. This product is structurally identical among the different classes of coelenterates: Hydrozoa (the jellyfish, Aequorea), Anthoz...

During the last 50 years, formation of the highly chromogenic copper cuprizone complex has been exploited for spectrophotometric determinations of copper although the precise chemical nature of the resulting species has never been ascertained; we eventually show here, in contrast to current opinion, that copper cuprizone is a copper(III)complex.

The work reported here is a continuation of earlier investigations on the chemical nature of two bactericidal substances, gramicidin and tyrocidine, isolated from cultures of Bacillus brevis (1-3). Christensen, Edwards, and Piersma are at the same time submitting a report of work which has been carried on independently in their laboratory (4). Tyrocidine hydrochloride and gramicidin are both co...