Origin of the Study

Rev..1988, 88, 563. A very detailed paper from the main originator of the studies of relativistic effects in chemistry. There are 428 references ... 

We will not attempt to credit the originators of the study of difference spectra, but will simply suggest that the work of Bastian (1949), Hiskey (1949), and Chance (1952) has played a major role in the popularization of the technique among chemists and biochemists. It was first applied to a... 

The origin of the study of animal reasoning is found in Wolfgang Kohler s The mentality of apes (Kohler 1925). Chimpanzees were observed to solve novel problems after exposure to the individual elements necessary for a solution. For example, exposure to boxes, and learning that one could pile them and stand on them, was later used to reach a suspended banana though the chimpanzee had never been taught to pile boxes as a way to reach food. An early recognition of individual... 

Detailed analyses of the above experiments suggest that the apparent steps in k E) may not arise from quantized transition state energy levels [110.111]. Transition state models used to interpret the ketene and acetaldehyde dissociation experiments are not consistent with the results of high-level ab initio calculations [110.111]. The steps observed for NO2 dissociation may originate from the opening of electronically excited dissociation chaimels [107.108]. It is also of interest that RRKM-like steps in k E) are not found from detailed quantum dynamical calculations of unimolecular dissociation [91.101.102.112]. More studies are needed of unimolecular reactions near tln-eshold to detennine whether tiiere are actual quantized transition states and steps in k E) and, if not, what is the origin of the apparent steps in the above measurements of k E). 

Reference [73] presents the first line-integral study between two excited states, namely, between the second and the third states in this series of states. Here, like before, the calculations are done for a fixed value of ri (results are reported for ri = 1.251 A) but in contrast to the previous study the origin of the system of coordinates is located at the point of this particulai conical intersection, that is, the (2,3) conical intersection. Accordingly, the two polar coordinates (adiabatic coupling term i.e. X(p (— C,2 c>(,2/ )) again employing chain rules for the transformation... 

Mechanistic studies have tried to unravel the origin of the special effect of water. Some authors erroneously have held aggregation phenomena responsible for the observed acceleration, whereas others have hinted at effects due to the internal pressure. However, detailed studies have identified two other effects that govern the rate of Diels-Alder reactions in water. 

Biosynthetic studies using acetate (Ac), propionate (Pr), and butyrate (Bu) revealed the polyketide nature of aurodox which has the composition Pr(Ac)g for the goldinamine skeleton C-7 to C-25 and the composition Bu(Ac) for the C-27 to C-39 carbon chain of goldinonic acid. In contrast to the methyl branch at C-8, those at C-19 and C-21 are methionine-derived as are all remaining methyl groups (52,53). The biogenetic origin of the pyridone moiety is not clear. 

The overall biosynthetic pathway to the tetracychnes has been reviewed (74). Studies (75—78) utilising labeled acetate and malonate and nmr analysis of the isolated oxytetracycline (2), have demonstrated the exclusive malonate origin of the tetracycline carbon skeleton, the carboxamide substituent, and the folding mode of the polyketide chain. Feeding experiments using [1- 02] acetate and analysis of the nmr isotope shift effects, led to the location of... 

The carbonated beverage has its origin in the study of mineral waters in Europe in the sixteenth century. In the late eighteenth century, artificial mineral waters were investigated for their medicinal properties both in Europe and America. The first commercial artificial mineral water was manufactured in Europe during the 1780s and in America in the early 1800s. 

The analysis indicated that the conformance problems associated with the hub design had a cost of failure of more than 30%. This would represent at the annual production quantity required and target selling price, a loss to the business of several million pounds. As a result of the study the business had further detailed discussions with their suppliers and not surprisingly it turned out that the supplier would only be prepared to stand by its original quotation provided the tolerances on the hub, discussed above, were opened up considerably (more than 50%). Subsequently, this result supported the adoption of another more capable design scheme. 

For copolymerizations between non protie monomers solvent effects are less marked. Indeed, early work concluded that the reactivity ratios in copolymerizations involving only non-protic monomers (eg. S, MMA, AN, VAe, etc.) should show no solvent dependence.100101 More recent studies on these and other systems (e.g. AN-S,102-105 E-VAc,106 MAN-S,107 MMA-S,10s "° MMA-VAc1" ) indicate small yet significant solvent effects (some recent data for AN-S copolymerization are shown in Table 8.5). However, the origin of the solvent effect in these cases is not clear. There have been various attempts to rationalize solvent effects on copolymerization by establishing correlations between radical reactivity and various solvent and monomer properties.71,72 97 99 None has been entirely successful. 

In the time and space available to me, I shall largely confine my comments to the origin of the chemical studies on this remarkable element. In so doing I shall include quotations from my Journal in order to help capture some of the flavor of this pioneering work. 

The difference in sulfonation behavior between a-olefins (AO) and internal olefins (IO) has been a longstanding problem [14] and the literature is replete with earlier explanations [14,15] and practical solutions [16-20] to the problem of IO sulfonation. In their studies of IO sulfonation chemistry, Stapersma and colleagues [4], Radici et al. [21], Yoshimura et al. [22,23], and Roberts and Jackson [24] identified the origins of the poor sulfonatability of IO, and the process modifications required to produce good-quality IO sulfonate. 

A chemist is studying the mechanism of the following hydrolysis reaction of the organic ester methyl acetate CH.COOCI I, + H,0 - CH,COOH + CH,OH. The question arises whether the O atom in the product methanol comes from the methyl acetate or from the water. Propose an experiment using isotopes that would allow the chemist to determine the origin of the oxygen atom. 

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