INDEX lability

The partition index (IR, which will be discussed in details below) of Cd, Cu, Cr, Ni and Zn in both soils rapidly increased from time zero (calculated value) to one day and further to one year. This was especially true for Cr, Cu and to some extent Ni and Cd (Table 6.5). This result indicates that added trace metals are initially and rapidly transferred from the labile EXC fraction into the more stable fractions. Furthermore, IR of trace metals in native arid soils incubated under the saturated paste regime decreased at the end of year. This indicates mobilization of trace elements in these soils as saturation (Table 6.5). Also, it can be seen that IR decreased, for any given time, with an increase of the loading level (Table 6.5, Fig. 6.5). This means that higher additions of soluble metals result in higher metal content in the labile fractions and lower metal binding intensity in soils. 

The lability of thieno[3,4-6]thiophene (3) and other iso-annelated systems, such as benzo[c]thiophene and benzole] furan, may be due to the strain effect (Mills-Nixon effect see also Zwanenburg et alP and references therein) in the condensed five-membered ring. The stability of the iso-annelated dithienothiophenes 7—9 is noteworthy. Simple LCAO MO method calculations on benzo[c]thiophene indicate that its instability is due to low specific delocalization energy and high free valence index at position 1. 

Protein hydrolysis in 6N HCl and subsequent analysis to determine amino acids (except tryptophan, which is acid labile) chemically present is a first step in protein quality evaluation. The chemical score and the EAA index represent attempts to use this information to chemically estimate nutritional quality of protein their obvious limitation is their disregard for amino acid availability. The chemical score is obtained by evaluating the percent of the limiting amino acid in comparison to that amino acid in whole egg protein ). The EAA index is the geometric mean of the ratios of each of the essential amino acids to those amino acids occurring in whole egg (4). 

Dinitrodiglycol exists in two crystalline forms—a stable form melting at a temperature of +2°C and a labile one whose melting point is —10.9°C (thus resembling nitroglycerine). At 20°C it is an oily liquid of density 1.385 g/cm3, boiling and simultaneously decomposing at 160°C. Its refractive index is 1.4517 (at 20°C). 

The Ji-complexes formed between chromium(O), vanadium(O) or other transition metals, and mono- or poly-fluorobenzene show extreme sensitivity to heat and are explosive [1,2], Hexafluorobenzenenickel(O) exploded at 70°C [3], and presence of two or more fluorine substituents leads to unstable, very explosive chromium(O) complexes [1]. Apparently, the aryl fluorine atoms are quite labile, and on decomposition M—F bonds are formed very exothermically. Laboratory workers should be wary of such behaviour in any haloarenemetal Ji-complex of this type [1]. However, in later work, no indications of explosivity, or indeed of any complex formation, were seen [4]. Individually indexed compounds are ... 

There have been some attempts to find chemical or physical correlates of short-term consumption that can be used as indices of biological lability (Amon et al., 2001). For example, there is indication that bioavailability (i.e., in terms of milligrams bacterial biomass per milligrams of DOC consumed) is correlated to the elemental composition in terms of C, N, H, and O, to the aliphatic contents, and to the overall degree of reduction of the DOM (Sun et al., 1997 Hopkinson et al., 1998 Hunt et al., 1999). However, there is still no general index that is applicable to all different aquatic systems, and it is unlikely that a single index will be able to account for variation in the multiple factors that simultaneously determine DOM... 

Ferrichrome iron transport in the enteric bacteria affords an experimentally feasible model for mechanistic studies. The ligand is rugged and can be labeled to high specific activity by microwave discharge activation of tritium gas. The labile ferric ion can be replaced with chromium to yield the kinetically stable isostructural chromic complex, chromichrome (61). Assuming this analog has the transport properties of the iron complex, its 3H counts would be an index of the behavior of... 

The measurement of lipid hydroperoxides in biological samples is frequently used as an index of lipid peroxidation. In practice such measurements are complicated by the lability of these compounds in the presence of metal ions, and thiols and by the metabolism of hydroperoxides by peroxidases such as glutathione peroxidase and the glutathione 5-transferases. 

Benzyloxy(cyano)carbene would be expected to be electrophilic by virtue of the calculated selectivity index, Wp -HjOccN 111- This has not yet been experimentally proved as 3-bcnzyloxy-3-cyano-3//-diazirine is rather labile and cannot be isolated if it is synthesized by the substitution of chlorine by a cyano group in 3-benzyloxy-3-chloro-3if-diazirine consequently, this substitution reaction is carried out in the presence of an alkene, hence, preparing 1-benzyloxy-cyclopropane-l-carbonitrile derivatives. However, the cyanide ion present in the system induces the polymerization of electrophilic alkenes, such as acrylonitrile or methyl acrylate. 

The lability to alkali " seems to be another reasonable index useful in the classification of dextrins. 

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