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From the practical viewpoint, enzyme-like synthetic catalysts, or syn-zymes, need not be specific for a given reactant structure. In nature enzymes distinguish among closely related molecules and transform only the substrate for which it is specific. Mixtures of molecules may not be involved in the industrial reaction to be catalyzed. Reaction specificity is, of course, a requirement. A synthetic hydrolase should not catalyze other reactions such as decarboxylation. Enzymes bring about rate enhancements of 10 -lO. A synzyme could be of great practical importance with far less efficiency than the natural enzyme if it is cheap and stable. In other words, a near miss in an attempt to mimic enzymes could be a fabulous success. [Pg.198]

As in the above example in which the wine quality is a somewhat ill-defined concept subject to individual taste, many classification schemes are often heavily biased by the viewpoint of the researcher (and this can influence the performance). Unsupervised learning (e.g. Ritter et al., 1992) largely avoids this bias but at the cost of often less powerful methods and the missing interpretation of the arising classes, where often it is not obvious what these classes represent. [Pg.160]

From a physicochemical viewpoint, those are indeed missing from the Ti-Al reaction couple. This is due mainly to large rates of their consumption in the formation of the TiAl3 layer, not simply to small rates of diffusion in their bulks. [Pg.144]

Now, for this purpose consider Eq. (153), where the direct damping y° is missing, from the viewpoint of classical statistical mechanics dealing with the theory of Brownian motion. First, this leads us to remove the trace over the basis related to the H-bond bridge slow mode in Eq. (153). [Pg.302]

These two examples emphasize the importance of maintaining a broad viewpoint in searching in order to avoid missing possibly important borderline periodicals. Many subjects are not exclusively the province of sharply defined fields. [Pg.96]

Artifacts due to immediate contacts of frontier cluster anions with positive PCs of the surrounding can be reduced if one substitutes these PCs with bare model potential cations (pseudopotential, PP), taken without basis functions. This helps to restore the repulsion between electron shells of anions of the cluster and cations of the environment, an interaction that is missing in a cluster embedding based in merely a PC array. Less efficient from the computational viewpoint is the brute force alternative where positive PCs at the cluster borders are replaced by all-electron (AE) cations in the latter case, one is forced to use formal (nominal) charges of the environmental ions and, as a rule, the QM cluster model is non-stoichiometric. [Pg.373]

The very extensive problems of the pollution of the hydrosphere by organic substances have been elaborated from different aspects in books, for example [24-29] and in numerous papers. Not all organic pollutants of the environment are considered here. For example, organic dyestuffs are missing, and so are the chlorinated dioxins and related derivatives [35] which are so topical from the environmental viewpoint [30-34], the chemical transformations of organic pollutants of the hydrosphere [36] whose importance is illustrated by few examples only from the field of photochemical transformations of pesticides, asbestos in waters [37] and other important groups of organic pollutants of the hydrosphere. [Pg.111]

Ti-awx-resveratrol is an especially important polyphenol derivative in wine from the viewpoint of anticancer effects. The chemical stracture of this compound resembles the hormone estradiol (Fig. 2.18). The substance in fact binds to estrogen receptors, it is sometimes called a phytoestrogen ( 3.24). However, resveratrol is much more important than its minor estrogen activity would make it appear. A very intensely studied— and also hotly debated—recent question is about the enhancement of the activity of an enzyme called sirtuirr Some researchers think that resveratrol increases this activity and helps preserve healthy cell functions. Some in vitro studies support this theory, but human clinical tests are still missing. Trans-... [Pg.67]

Accident statistics will be useful in identifying uncontrolled risks as they will present- if properly analysed from a causal viewpoint-data indicative of where control action should have been taken to prevent recurrence. Ideally, an analysis of all injury, damage and near-miss accidents should be undertaken, so that underlying trends may be highlighted and effective control action - both organisational and physical in nature - taken. [Pg.161]

Niels Bohr in Copenhagen stated from a theoretical viewpoint that Urbain s celtium could not be element 72. As the missing metal belongs to group 4 it should... [Pg.527]

When excellence in safety is measured by zero failures, a self-limiting organizational viewpoint and very dangerous employee belief is created Ifsafety means no incidents, then anything that I do that doesn t result in an incident or get me hurt, must be safe. When this occurs, risk will be overlooked, complacency will set in, an important and healthy degree of vulnerability of risk will be lost, and organizations will be surprised by an incident that occurs out of nowhere. This will often sound like I can t believe that experienced, well-trained employee did that, or, How did we miss that . [Pg.25]

A different viewpoint was expressed by Mothes (1966a,b) Secondary plant substances are not essential to the existence of plants. Therefore, they can (may) be missing from individual members of a related group (of plants). They are not an inherent taxonomic characteristic. ... [Pg.6]

When, many years ago, 1 turned to the study of gnosticism I found that the viewpoints... which 1 had acquired in the school of Heidegger, enabled me to see aspects of gnostic thought that had been missed before. ... [Pg.14]


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See also in sourсe #XX -- [ Pg.230 , Pg.244 , Pg.245 , Pg.246 , Pg.247 , Pg.248 ]




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