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Oxidation-reduction potential Because of the interest in bacterial corrosion under anaerobic conditions, the oxidation-reduction situation in the soil was suggested as an indication of expected corrosion rates. The work of Starkey and Wight , McVey , and others led to the development and testing of the so-called redox probe. The probe with platinum electrodes and copper sulphate reference cells has been described as difficult to clean. Hence, results are difficult to reproduce. At the present time this procedure does not seem adapted to use in field tests. Of more importance is the fact that the data obtained by the redox method simply indicate anaerobic situations in the soil. Such data would be effective in predicting anaerobic corrosion by sulphate-reducing bacteria, but would fail to give any information regarding other types of corrosion. 

Some cyclopropylcarboxylic acids, namely 14 [125] and 15 [46] could be coupled to bicyclopropyl compounds, others led to allylic compounds via ring opening of an intermediate carbenium ion (see chap. 7). Tertiary alkanoates yield predominantly non-Kolbe products (see chap. 8). 

I have noted that NPPB is structurally related to loop diuretics of the furosemide (Fig. 2) type. These latter compounds bind to the Na 2CNK -cotransporter [16] and inhibit NaCl reabsorption in the TAL segment and NaCl secretion in epithelia such as the colonic crypt cell and rectal gland of Squalus acanthias [15]. We were able to show that only minor modification of the NPPB molecule on one side and of furosemide on the other led to compounds with altered selectivities [70,91-93]. One prototype of an intermediate blocker, i.e., a substance blocking both Na 2Cl K -cotransport and CP-channels, is torasemide (Fig. 2). Hence we have performed a systematic study in order to define the constraints defining the effectiveness of this class of substances [91]. 

FVP of the aza-bicyclic sulfone 236 at 700°C and 8xl0 2mbar resulted in 3//-pyrrolizin-3-one 237 <2004TL3889>. At same temperature and lower pressure, that is, 4 x 10-2 mbar, the same sulfone affords a mixture of 237 and vinyl pyrrole 238 in 44% and 27% yield, respectively. The latter was the only product obtained when the thermolysis of 236 was performed in a sealed tube in sulfolane. This result and others led Pinho e Melo et al. <2005JOC6629> to suggest the plausible eight-step mechanism shown in Scheme 61. 

For over 2,000 years, alchemy was the only chemistry studied. Alchemy was the predecessor of modern chemistry and contributed to the slow growth of what we know about the Earth s chemical elements. For example, the alchemists interest in a common treatment for all diseases led to the scientific basis for the art of modern medicine. In particular, the alchemist/ physician Paracelsus (1493-1541) introduced a new era of medicine known as iatrochemistry, which is chemistry applied to medicine. In addition, alchemists elementary understanding of how different substances react with each other led to the concepts of atoms and their interactions to form compounds. 

Cerium was the first rare-earth element discovered, and its discovery came in 1803 by Jons Jakob Berzelius in Vienna. Johann Gadohn (1760—1852) also studied some minerals that were different from others known at that time. Because they were different from the common earth elements but were all very similar to each other, he named them rare-earth elements. However, he was unable to separate or identify them. In the 1800s only two rare-earths were known. At that time, they were known as yttria and ceria. Carl Gustav Mosander (1797—1858) and several other scientists attempted to separate the impurities in these two elements. In 1839 Mosander treated cerium nitrate with dilute nitric acid, which yielded a new rare-earth oxide he called lanthanum. Mosander is credited with its discovery. This caused a change in the periodic table because the separation produced two new elements. Mosander s method for separating rare-earths from a common mineral or from each other led other chemists to use... 

Hamilton Wright, appointed U.S. opium commissioner in 1908 and vigorous opponent of use of opium. His efforts and those of many others led to passage of the Harrison Narcotics Act, which allowed use of narcotics for legitimate medical purposes only and greatly reduced abuse of opium products in the United States. 

The knowledge that it could be solidified, acquired by the academicians of Petersburg in 1750, was the first moans to remove the notion of its semi-metallic nature, and inquiries to which the announcement of the fact gave rise in tho hands of Pallas, Hutchins, Bieker, Blagden, and several others, led the way to Its recognition as a true metal, and elementery body. 

I he observations of Lavoisier, Proust, and others led John Dalton (1766— 1 1844), a self-educated English schoolteacher, to reintroduce the atomic ideas of Democritus. In 1803, Dalton wrote a series of postulates—claims he... 

Resolution of the anomalies between our analytical results and others led us to the postulate that these slope sediments contained organic matter which had not only been deposited in the marine organic realm but had also originated there. (Most previous analyses reported in the literature were on organic matter either from the terrestrial organic realm or from zones where there was admixing.)... 

Two modes of dimerization of the 2-alkyl-6-methyl-4//-l,3-thiazine-4-one (249) have been observed (83CC56). One mode gave the linearly combined dimer 250, and the other led to a spiro compound (251). The structure of one of the spiro compounds was confirmed by X-ray crystallography (Scheme 101). The reactions occurred when the 2-alkyl group was methyl, ethyl, or n-propyl, but not when it was isopropyl. 4-Acyloxy-and 4-p-tosyloxy-l,3-thiazine-6-ones (253) have been prepared by acylation and sulfonylation starting from thiazine-4,6-diones (252), in a solvent, at temperatures from room temperature to reflux (Scheme 102) (79KGS44). 

Ancient cultures thought there were only a handful of elements that made up all the matter in the world. The idea that these few elements could be mixed into any material led to the development of alchemy. Part scientists and part philosophers, alchemists searched for a way to turn common metal into gold. Their experiments paved the way for true chemists research in the seventeenth and eighteenth centuries. Experiments by Robert Boyle, Antoine Laurent de Lavoisier, John Dalton, and others led to new... 

A very useful identification tool is the combination of GC and thin-layer chromatography (TLC). The first work on combined GC-TLC appears to have been by Janak [59]. The GC column effluent is split into two streams, one of which enters the detector and the other, led via a heated conduit, impinges on the chromatographic thin layer carried by a moving plate. The GC fractions sampled in this way are subsequently developed and the TLC spots detected in the usual manner. The result is a kind of two-dimensional thin-... 

Isopropyl derivatives were introduced by Pettitt and Stouffer [287] and later studied by other workers [288]. They are prepared by reaction with 2-bromopropane in the presence of sodium hydride in dimethyl sulphoxide. The reaction scheme and the preparation procedure were given in Chapter 4 (see p. 64). Except for Arg, all amino acids under study provided the expected derivatives. The hydroxyl group of Hypro was, however, not protected. The derivatives were found to be stable for a reasonable period of time and were analysed on 3% of OV-17. The extension of this promising one-step method to all protein amino acids did not fulfill expectations, however [288]. Some amino acids (Gly, Gin, Asp and Asn) did not provide detectable derivatives and the others led to multiple peaks. Moreover, significant amounts of by-products were produced, which may interfere. Arg provided a single peak, the mass spectrum of which was identical with that of Orn both derivatives resulted from lactam formation. Isoprop derivatives of 23 common amino acids were separated on 5% of-Carbowax 20M on silanized Chromosorb G with temperature programming (50-240°C). 

The first transuranic element was produced in 1940. Neptunium (Z = 93) results from the capture of a neutron by U, followed by beta decay. Subsequent work by the American chemist Glenn Seaborg and others led to the production of plutonium (Z = 94) and heavier elements. In recent years, nuclides with Z as high as 116 have been made, but in tiny quantities. These nuclides have very short half-lives. 

These investors and others sponsored and supported a number of proxy resolutions on disclosure of climate change risk, some of which resulted in direct votes of shareholders while others led to negotiated agreements to meet the general terms of the resolution. 

A comparison of the secondary structure of this enzyme with others led to the conclusion that this oxynitrilase belongs to the family of the a, /3-hydrolase fold enzymes [74 - 76] (Fig. 3). 

Above the need—as alchemists saw it— to conceal their arts from all but each other led to a weird literature in which fantastic creatures were used as symbols only intelligible to the initiated. In this manuscript of 1572 a dragon resuscitated after death stands for one specific process. 

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