Aureol

The rupture process of a soap film is of some interest. In the case of a film spanning a frame, as in Fig. XIV-15, it is known that rupture tends to originate at the margin, as shown in the classic studies of Mysels [207, 211]. Rupture away from a border may occur spontaneously but is usually studied by using a spark [212] as a trigger (a-radia-tion will also initiate rupture [213]). An aureole or ridge of accumulated material may be seen on the rim of the growing hole [212, 214] (see also Refs. 215, 216). Theoretical analysis has been in the form of nucleation [217, 218] or thin-film instability [219]. 

Figure 5.8 Heavily pitted surface of a mild steel cooling water return line. Note the deep localized metal loss surrounded by aureoles of rust. Pitting is common when oxygen concentration varies greatly over time.

Pit interiors are characteristically smooth and distinctly hemispherical, but become rougher on less-noble alloys. Pits tend to cluster together, overlapping to form irregularly dimpled surfaces. Frequently, a lightly etched aureole surrounds the pit clusters. These etched areas are often produced by shallow corrosion beneath deposit and slime masses that covered the sulfate reducers in service (Figs. 6.3 and 6.4A and B). 

Hayashi, H. (1961) Mineralogical study on alteration products from altered aureole of some Kuroko deposits. J. Mineral Soc. Japan, 5, 101-125 (in Japanese). 

Aureolic acid group of antibiotics We have given below an extended summary of the work done with this group of antibiotics, because we have been actively involved in understanding the mode of action of these DNA-binding antibiotics. The summary also illustrates the model example of how different biophysical and biochemical approaches were undertaken to characterize the association of these drugs with chromosomal DNA and the sequential effect of this binding upon the chromatin structure. 

Greenwood H. J. (1967). Wollastonite Stability in H2O-CO2 mixtures and occurrence in a contact metamorphic aureole near Salmo, British Columbia, Canada. Amer. Mineral, 52 1669-1680. 

Fig. 1. Regional geology surrounding the Morila Au Mine, southern Mali. The deposit is hosted by immature Birimian metasediments and is proximal to a large composite post-Eburnean D2 pluton (Doubalkoro) and within a localized low-P contact aureole.

Because the isotopic composition of igneous rocks is quite different from those of sedimentary rocks, studies of the isotope variations in the vicinity of an intrusive contact offer the possibihty of investigating the role of fluids interacting with rocks around cooling plutons. Two types of aureole can be distinguished (Nabelek 1991)... 

Georg RB, Reynolds BC, Frank M, Halhday AN (2006) Mechanisms controlhng the silicon isotopic compositions of river water. Earth Planetary Sci Lett 249 290-306 Gerdes ML, Baumgartner LP, Person M, Rumble D (1995) One- and two-dimensional models of fluid flow and stable isotope exchange at an outcrop in the Adamello contact aureole, Southern Alps, Italy. Am Miner 80 1004-1019... 

Taylor BE, Bucher-Nurminen K (1986) Oxygen and carbon isotope and cation geochemistry of metasomatic carbonates and fluids - Bergell aureole, Northern Italy, Geochim Cosmochim Acta 50 1267-1279... 

Teng FZ, McDonough WF, Rudnick RL, Wing BA (2007) Limited lithium isotopic fractionation during progressive metamorphic dehydration in metapelites a case study from the Onawa contact aureole, Maine, Chem Geol 239 1-12... 

To date, few carbohydrate interactions with DNA have involved interactions within the major groove. Among the classes of compounds known to exhibit DNA binding are enediyne antibiotics, anthracydines, pluramycins, indolocar-bazoles, and aureolic acids. Of the limited number of carbohydrates known for DNA binding, only a select few have displayed major groove contacts. These... 

The present contribution centers on stereoselective syntheses of mono- and in particular oligo-saccharides of the 2-deoxy- and the 2,6-dideoxy series as well as some branched-chain species. These are the principal sugar portions in a large number of important natural glycosides, such as the cardiac glycosides (3), the orthosomy-cins (D, the tetronic acids (5), the aureolic acids (6, see below), and the anthracyclines (2, see below), to name just a few. 

A further natural product inhibitor is mithramydn A, a structurally complex anticancer antibiotic. Mithramycin A is a member of a group of aureolic add-type polyketides that are produced by the soil bacterium Streptomyces argillaceus [94]. 

Giere, R. Williams, C. T. 1992. REE-bearing minerals in a Ti-rich vein from the Adamello contact aureole (Italy). Contributions to Mineralogy and Petrology, 112, 83-100. 

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