Substance structure

Common Name Zearalanol, tetrahydro F.E.S. (fermentation estrogenic substance) Structural Formula ... 

Further characteristic assignments of substance structures to wavelength ranges that are absorbable are to be found in the specialist literature [2, 11-14]. The publications of the research groups of Fassler [15,16] and Oelkrug [17-19] reveal that the sorbent can exert a considerable additional effect. 

S is the entropic factor, which depends on Eb and the chemical substance structure ... 

Thermodynamically unstable substances (structure below) that serve as enzymatic reaction intermediates and are typically formed by carboxylation carboxyl group transfer) of a sulfhydryl group on a cysteinyl residue of an enzyme. 

Figure 9.10 (a) Schematic soil humic acid structure proposed by Schulten and Schnitzer (1997). Note that the symbols stand for a linkages in the macromolecules to more of the same types of structure. (b) Schematic seawater humic substances structure proposed by Zafiriou et al. (1984). (c) Schematic black carbon structure proposed by Sergides et al. (1987). 

Davies, G., and E. Ghabbour, Eds., Humic Substances Structures, Properties and Uses, Royal Society of Chemistry, Cambridge, UK, 1998. 

Liu, C., and Huang, P. M. (2001). The influence of catechol humification on surface properties of metal oxides. In Humic Substances Structure, Models and Functions, Ghabbour, E. A. and Davies, G, eds., Royal Society of Chemistry, Cambridge, UK, pp. 253-270. 

Senesi, N., and Steelink, C. (1989). Application of ESR spectroscopy to the study of humic substance structure. In Humic Substances II. In Search of Structure, Hayes, M. B. H., MacCarthy, R, Malcolm, R., and Swift, R., eds., John Wiley Sons, New York, pp. 373 107. 

Three different viewpoints on the humic substances structural conformation are actually reported in the literature. One suggests that HS are macromolecular and assume random coil conformations in solution (Swift, 1999) a second proposes that HS are molecular associations of relatively small molecules held together by weak interaction forces, thus forming a supramolecular structure (Piccolo and Conte, 1999) a third considers that HS are in solution as micelles or pseudomicellar structures (Wershaw, 1999). Viewpoints two and three could be broadly considered to be under the same umbrella (Clapp and Hayes, 1999). 

These include mannitol and sorbitol which act mainly in the proximal tubules to prevent reabsorption of water. These polyhydric alcohols cannot be absorbed and therefore bind a corresponding volume of water. Since body cells lack transport mechanisms for these substances (structure on p.175), they also cannot be absorbed through the intestinal epithelium and thus need to be given by intravenous infusion. The result of osmotic diuresis is a large volume of dilute urine, as in decompensated diabetes melli-tus. Osmotic diuretics are indicated in the prophylaxis of renal hypovolemic failure, the mobilization of brain edema, and the treatment of acute glaucoma attacks (p. 346). 

Leenheer, J.A., Organic substance structures that facilitate contaminant transport and transformations in aquatic sediments, in Humics and Soils, vol. 1 of Organic Substances and Sediments in Water series, Lewis Publishers, Chelsea, CA, 1991. 

In some liquids, a deviation (Fig. 5.27) occurs from the straight-line log D versus 1/r plots expected on the basis of the empirical exponential law for the diffusion coefficient (Eq. 5.55). An example of such a deviating liquid electrolyte is molten ZnCl2, but in the case of this substance, structural changes have been noted with increasing temperature. This seems to be a reasonable explanation for the deviation from the straight-line log D versus 1/Tplot. 

In 2009, there were two ways to access from a client version installed on a computer or via web access. The client version is being phased out as the web version is being developed. Both versions have the same functionality. Advantages of SciFinder include the ability to combine answer sets and the ability to see all the substances linked to an abstract in a grid layout. Clicking on a substance structure or registry number allows the user to modify the structure for future searches or to explore reactions. SciFinder also provides access to the full text of the article through the ChemPort Connection. This allows the user to directly access the article when permissions for access are enabled or to purchase the article when they are not enabled. 

Kramer R. W., Kujawinski E. B., ZangX., Green-Church K. B., Jones R. B., Freitas M. A., and Hatcher P. G. (2001) Studies of the structure of humic substances by electrospray ionization coupled to a quadrupole-time of flight (QQ-TOF) mass spectrometer. In Humic Substances Structures, Models and Functions (eds. E. A. Ghabbour and G. Davies). The Royal Society of Chemistry, Cambridge, England, pp. 95-107. 

Erau9ois R. (1990) Marine sedimentary humic substances structure, genesis, and properties. Rev. Aquat. Sci. 3, 41 -80. 

Carotenoid-like Compounds. Synthetic procedures for construction of the rings of ionones and other substances structurally related to carotenoids, and other procedures for the preparation and transformations of such compounds, may be useful in the carotenoid field. Thus reaction between the phenyl sulphide (143) and the... 

It is usually desirable to fractionate aquatic humic substances by only one interaction mechanism operating at a time. Unfortunately, the complexity of aquatic humic substance structures and properties usually causes multiple... 

The X-ray diffractometry technique obtains information on substance structure at the atomic level. This technique allows measurement of both crystalline and noncrystalline materials. The analysis is nondestructive in nature and handles samples in the form of powders, solids, and liquids. The X-ray diffraction of a single crystal is employed for the determination of the absolute chemical structure. Powder diffraction is used for fingerprint purposes. Polymorphism may be identified by diffraction patterns with d-spacing that has... 

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