Speculations

The ability to bind zinc stoichiometrically at subnanomolar concentrations (Fig. 1) suggests that thionein may play a significant role in limiting the intracellular concentration of Zn and, hence, in modulating the activity of zinc-dependent processes. The measured binding constant of 7 x 10 allows the inference that all systems with more moderate affinity for zinc, i.e., 10 are potential targets for competition by thionein, among 

Acknowledgements. This work was supported by grants to J.H.R. Kagi from the Swiss National Science Foundation (grant 3100-31012.91), the Kanton Zurich, and the Bonizzi-Theler Stiftung. 

Ahmed S, Kozma R, Lee J, Monfries C, Harden N, Lim L (1991) The cysteine-rich domain of human proteins, neuronal chimaerin, protein kinase C and diacylglycerol kinase binds zinc. Biochem J 280 233-241 Andrews GK, Adamson ED, Gedamu L (1984) The ontogeny of expression of murine metallothionein comparison with the a-fetoprotein gene. Dev Biol 103 294-303 

Baleja JD, Marmorstein R, Harrison SC, Wagner G (1992) Solution structure of the DNA-binding domain of CD2-GAL4 from S. cerevisiae. Nature 356 450-453 

Berg JM (1989) DNA binding specificity of steroid receptors. Cell 57 1065-1068 Berg JM (1990) Zinc fingers and other metal-binding domains. J Biol Chem 265 6513-6516 

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While pressure melting may be important for snow and ice near 0°C, it is possible that even here an alternative explanation will prove important. Ice is a substance of unusual structural complexity, and it has been speculated that a liquidlike surface layer is present near the melting point [17,18] if this is correct, the low /t values observed at low sliding speeds near 0°C may be due to a peculiarity of the surface nature of ice rather than to pressure melting. 

As usual, things become more complicated when studied in detail. Note that for 0/W(l 10) 0 varies with 6 the situation is shown more fully in Fig. XVIII-15. The authors speculate that variations in Dq and E have to do with a p(2 x 1) structure at low oxygen coverage, with O atoms occupying alternate rows of W atoms, the empty rows becoming occupied above 0 = 0.5. The consequence is that O—O interactions shift from being mostly attractive to being in part repulsive. 

For a polyatomic, there are many questions on the role of the polyad number in energy flow from the molecule to the bath. Does polyad number conservation in the isolated molecule inlhbit energy flow to the batii Is polyad number breaking a facilitator or even a prerequisite for energy flow Finally, does the energy flow to the bath increase the polyad number breaking in the molecule One can only speculate until these questions become accessible to fiiture research. 

The view of this author is that knowledge of the internal molecular motions, perhaps as outlined in this chapter, is likely to be important in achieving successfiil control, in approaches that make use of coherent light sources and quantum mechanical coherence. However, at this point, opinions on these issues may not be much more than speculation. 

The pseudopotential is derived from an all-electron SIC-LDA atomic potential. The relaxation correction takes into account the relaxation of the electronic system upon the excitation of an electron [44]- The authors speculate that ... the ability of the SIRC potential to produce considerably better band structures than DFT-LDA may reflect an extra nonlocality in the SIRC pseudopotential, related to the nonlocality or orbital dependence in the SIC all-electron potential. In addition, it may mimic some of the energy and the non-local space dependence of the self-energy operator occurring in the GW approximation of the electronic many body problem [45]. 

It is an interesting speculation as to how much more difficult the isolation of these two elements might have been if the periodic classification had not provided us with a very good preview of their chemistries. 

When g = 1 the extensivity of the entropy can be used to derive the Boltzmann entropy equation 5 = fc In W in the microcanonical ensemble. When g 1, it is the odd property that the generalization of the entropy Sq is not extensive that leads to the peculiar form of the probability distribution. The non-extensivity of Sq has led to speculation that Tsallis statistics may be applicable to gravitational systems where interaction length scales comparable to the system size violate the assumptions underlying Gibbs-Boltzmann statistics. [4]... 

A porous medium may be regarded as a complex assembly of interconnected channels and, if each of these is regarded as a capillary Cube, one is led to speculate that a flux relation of the algebraic form (2.5) might be appropriate v en all the channels have diameters much smaller chan the mean... 

A proper resolution of Che status of Che stoichiometric relations in the theory of steady states of catalyst pellets would be very desirable. Stewart s argument and the other fragmentary results presently available suggest they may always be satisfied for a single reaction when the boundary conditions correspond Co a uniform environment with no mass transfer resistance at the surface, regardless of the number of substances in Che mixture, the shape of the pellet, or the particular flux model used. However, this is no more than informed and perhaps wishful speculation. 

Several alternative attempts have been made to quantify Lewis-acid Lewis-base interaction. In view of the HSAB theory, the applicability of a scale which describes Lewis acidity with only one parameter will be unavoidably restricted to a narrow range of struchirally related Lewis bases. The use of more than one parameter results in relationships with a more general validity ". However, a quantitative prediction of the gas-phase stabilities of Lewis-acid Lewis-base complexes is still difficult. Hence the interpretation, not to mention the prediction, of solvent effects on Lewis-add Lewis-base interactions remains largely speculative. 

The unexpected preference for the interfacial region at lower concentrations of benzene has prompted speculation. It has been demonstrated that aromatic compounds are capable of forming weak hydrogen bonds with water. This ability favours uptake in the aqueous interface over solubilisation in the interior. Alternatively, some authors have attributed the binding behaviour of benzene to its... 

This conclusion seems in coirflict with the outcome of the analysis using the pseudophase model. Here we do not speculate on the origins of this discrepancy. Instead, an extensive discussion is provided in Section 5.2.3. 

Whereas most chemists focused their attention on speculation about atoms and the question of atomic weights, the constant multiplicity in compounds occupied an increasingly central role. The new concept of substitution, i.e., the replacement of one element by another in a compound, started to make a major impact on chemistry in the 1840s. It was probably Dumas, who in the 1830s at the request of his father-in-law (who was the director of the famous Royal Sevres porcelain factory) resolved an event that upset a royal dinner party at the Tuil-... 

Synthesis It s difficult to find out how drug companies make their products (understandably ) so we can only speculate ... 

The method has not been studied extensively and is restricted to the preparation of alkyl-, aryl-, or alkoxy-substituted thiazoles mostly in 2-, 5-, or 2,5-positions. Yields ranged from 45 to 80%. Sometimes this method gives good results when the usual Hantzsch s synthesis fails. There has been very little speculation about the mechanism of this reaction. 

When the experiment was carried out in the fall of 1985 Kroto Curl and Smalley found that un der certain conditions a species with a molecular for mula of Ceo was present in amounts much greater than any other On speculating about what Ceo might be they concluded that its most likely structure is... 

Speculation about the stability of Ceo centered on the extent to which the aromaticity associated with its 20 benzene rings is degraded by their non planarity and the accompanying angle strain It is now clear that Ceo is a relatively reactive substance reacting with many substances toward which ben zene itself is inert Many of these reactions are char acterized by addition to buckminsterfullerene converting sp hybridized carbons to sp hybridized ones and reducing the overall strain... 

Once the broad outlines of DNA replication and protein biosynthesis were established scien tists speculated about how these outlines af fected various origins of life scenarios A key question concerned the fact that proteins are re quired for the synthesis of DNA yet the synthesis of these proteins is coded for by DNA Which came first DNA or proteins How could DNA store genetic infor mation if there were no enzymes to catalyze the polymerization of its nucleotide components How could there be proteins if there were no DNA to code for them ... 

Type V isotherms of water on carbon display a considerable variety of detail, as may be gathered from the representative examples collected in Fig. 5.14. Hysteresis is invariably present, but in some cases there are well defined loops (Fig. 5.14(b). (t ), (capillary-condensed water. Extreme low-pressure hysteresis, as in Fig. 5.14(c) is very probably due to penetration effects of the kind discussed in Chapter 4. 

The fluorescent emission for quinine at 450 nm can be induced using an excitation frequency of either 250 nm or 350 nm. The fluorescent quantum efficiency is known to be the same for either excitation wavelength, and the UV absorption spectrum shows that 250 is greater than 350- Nevertheless, fluorescent emission intensity is greater when using 350 nm as the excitation wavelength. Speculate on why this is the case. 

Other patents (81,82) coveted the preparation of cellulose solutions using NMMO and speculated about their use as dialysis membranes, food casings (sausage skins), fibers, films, paper coatings, and nonwoven binders. NMMO emerged as the best of the amine oxides, and its commercial potential was demonstrated by American Enka (83,84). Others (85) have studied the cellulose-NMMO system in depth one paper indicates that further strength increases can be obtained by adding ammonium chloride or calcium chloride to the dope (86). 

It has been shown that keratin [9008-18-8] and not ceUulose-type fibers, are dyed. It is speculated that a lead—sulfur—keratin complex is formed. The color penetrates the hair fiber to a limited extent, forming a ring around the outside edge and imparting a lifeless appearance. Once developed, the color cannot be removed. The shades are limited yeUows or light browns. Appealing mainly to men, the products are often called color restorers because of the... 

In 1966, the name was proposed (5) for receptors blocked by the at that time known antihistamines. It was also speculated that the other actions of histamine were likely to be mediated by other histamine receptors. The existence of the H2 receptor was accepted in 1972 (6) and the receptor was recognized in rat brain in 1983 (7). receptors in the brain appear to be involved in the feedback control of both histamine synthesis and release, whereas release of various other neurotransmitters, eg, serotinin (5-HT), dopamine, noradrenaline, and acetylcholine, is also modulated (8) (see Neuroregulators). 

Demonstrated reserve quantities are estabUshed by measurements including drillings surface sampling, etc. Inferred reserves are those derived from geological survey information, not by measurement of the extent of the particular reserve. Not included herein are identified marginal and speculative resources, such as the oil-field and geothermal brines and lithium-hearing clays. These latter reserves are speculative as to extent, not existence. Total undiscovered clays in the western United States are speculatively estimated at 15 x 10 t lithium (16). More detailed Hsts of reserves are also available (15,17). 

Informed opinion is a nonmathematical technique which is often called blue-sky estimating. The two terms are not necessarily synonymous. Informed opinion may be the consensus of people inside the company, along with or without outside opinions. Such a consensus can be broadened into the Delphi technique, which uses a sequential series of questioimaires submitted to a panel of experts who have Httie or no contact with each other. Blue-sky answers are akin to the informed opinion except that they usually consist of subjective speculation by experts in a confined one-day meeting in which each participant knows the views of the others. 

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