A Fortuitous Observation

The adsorption ratios, A = a/ observed thus far for atactic and isotactic systems indicate that self-association can occur in two ways either by expulsion of already-adsorbed molecules (i.e. in the cases that A is <1) or by addition of more adsorbed molecules (i.e. in the cases that A is > 1). Why this is so is not understood. It is curious to note, however, that the solvent in those P-L systems with A > 1 is in every case a cyclic aliphatic liquid, the ring structure of which contains no more than one atom that is not carbon (Nos. 1, 2, 14, and 15 Table 20), whereas none of the solvents in a P-L system with A < 1 is in this category. Because the number of a reported thus far are relatively few (Table 20), owing to the time-consuming procedure and the high technical skill required to obtain data via the protocol described by Guenet, it is not yet possible to adjudicate with certainty whether or not this cyclic vs acyclic differentiation is a real phenomenon or just a fortuitous observation. It does suggest the possibility, however, that the mode of adsorption in the case of cyclic aliphatic molecules may be qualitatively different from that for acyclic molecules. 

Seale-up of the apparatus is predieted to deerease the total number of attrition partieles and reduee the proportion of fines eontributed by impeller impaet relative to turbulent fluid erosion of parent partieles, but it was eon-eluded more work is still neeessary to quantify and experimentally eonfirm those aspeets. The implieation, however, is that mean erystal size inereases with seale up - a fortuitous result often observed in praetiee. 

Can a fortuitous combination of mechanisms (8.43) and (8.44A) account for the observed hydrogen-label distribution in the formation of semi-bullvalene from barrelene If so, how can you eliminate this possibility ... 

The examples found in the literature concern mostly oligopeptides, with the reactive N-terminal amino acid being Gly, His, or Arg. Interestingly, the former is particularly flexible, whereas His and Arg contain a basic side chain. Whether these are fortuitous observations or have general value remains to be seen. 

Whether or not the effect can be obtained for a particular element depends on a fortuitous combination of half-life and nuclear energy levels. While many elements have yielded such spectra, the system represented by iron-57 (natural abundance approximately 2%) is the easiest to observe, and excellent results are obtained even at room temperature—hence the interest in the method for studying iron compounds in art and archaeology. While most MES data have been collected with transmission geometry, which requires either thin samples or some sample preparation to achieve thinness, data collection by scattering allows one to achieve the same results with no sample preparation whatsoever—i.e., if the compound to be studied lies at or very near the surface of the material in which the compound occurs. For example, in a sample of a typical iron oxide, the analysis would pertain to a surface layer approximately 0.2 mm deep. 

Tricyclic antidepressants—so called because of the characteristic three-ring nucleus—have been used clinically for four decades (Figure 30-1). They closely resemble the phenothiazines chemically and, to a lesser extent, pharmacologically. Like the latter drugs, they were first thought to be useful as antihistamines with sedative properties and later as antipsychotics. The discovery of their antidepressant properties was a fortuitous clinical observation. Imipramine and amitriptyline are the prototypical drugs of the class as mixed norepinephrine and serotonin uptake inhibitors though they also have several other properties. 

Agreement with Raoult s Law is not a sufficient condition for ideality —though it is a necessary one (627). Occasionally a mixture capable of H bonding will form a pseudo-ideal system which obeys the equation. Pyridine-ethanol is an example (227) which must include H bonding, both in association of the alcohol and between the two components. The observed ideal behavior surely results from a fortuitous cancellation of effects. 

The activity of exogenous chemical substances on the human organism can be observed under various circumstances eth-nopharmacology, popular medicines, clinical observation of secondary effects or adverse events, fortuitous observation of activities of industrial chemical products, etc. As in all cases, the harvested information is observed directly in man, this approach presents a notable advantage. 

The theoretical linear dependence of a versus D2O/H2O for a two phases system, is only observed for the high water content samples. A large deviation drom the linearity occurs in the 9 % water content specimen. The two phase approximation is therefore less valid in this sample and the superposition which was observed may result from a fortuitous choice of multiplication constants. 

Taking the two carbonyl compounds in Fig. 1 as illustrative examples, HF calculations using smaller basis sets can actually give better agreement with experiment, especially for [Ni(CO)4] [77] where the 3-21G basis yields an Ni-C contact only 0.007 A shorter than observed. This is the result of a fortuitous cancellation of errors [78]. Configuration Interaction leads to a significant improvement for both molecules [76, 79-81]. 

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