Alkalinity correlation with

A similar activation of urea hydrolysis is seen when pH measurements are made in the cytosensor and the rate of alkalinization correlated with urease activity, as shown in the figure on the opposite page. This also differs from previous investigations, because acid is constantly added to the organisms, and inactivation of the mechanism for enhancement of urease activity does not occur. There is approximately a 40-fold activation of urease activity as the pH falls to below 4.0. At higher pH, in the small volume of the chamber, urease activity is able to elevate chamber pH very rapidly hence, urease activity is only transient. At a pH of 3.0, the level of acid is sufficient to require significant levels of urease activity to attempt to elevate pH. These... 

Hammen equation A correlation between the structure and reactivity in the side chain derivatives of aromatic compounds. Its derivation follows from many comparisons between rate constants for various reactions and the equilibrium constants for other reactions, or other functions of molecules which can be measured (e g. the i.r. carbonyl group stretching frequency). For example the dissociation constants of a series of para substituted (O2N —, MeO —, Cl —, etc.) benzoic acids correlate with the rate constant k for the alkaline hydrolysis of para substituted benzyl chlorides. If log Kq is plotted against log k, the data fall on a straight line. Similar results are obtained for meta substituted derivatives but not for orthosubstituted derivatives. 

It was found (32) that in the acid range (pH 4—6) the alkyl group does not influence the rate of decomposition, which is similar for all xanthates. In the alkaline range the rates are markedly influenced by the substitutional group, and the rates could be correlated with the Taft polar substituent constants estabhshed for the various groups. 

The alkaline and rare-earth metals, and positive actinide ions, generally have greater affinity for —0 groups as electron donors. Many transition metals complex preferentially with enoHc —0 and some nitrogen functions. PolarizabiUty of the donor atoms correlates with stabiUty of complexes of the heavier transition metals and the more noble metal ions. 

Correlations with o in carboxylic acid derivative reactions have been most successful for variations in the acyl portion, R in RCOX. Variation in the alkyl portion of esters, R in RCOOR, has not led to many good correlations, although use of relative rates of alkaline and acidic reactions, as in the defining relation, can generate linear correlations. The failure to achieve satisfactory correlations with cr for such substrates may be a consequence of the different steric effects of substituents in the acyl and alkyl locations. It has been shown that solvolysis rates of some acetates are related to the pA", of the leaving group, that is, of the parent alcohol. The pK of alcohols has been correlated with but this relationship... 

Table 3 shows that the distribution of alkaline batteries correlates with the statistics of per-capita income. Zn-carbon batteries can be afforded more easily, alkaline batteries cost at least twice as much. However, the electronic "push" for high-quality batteries with good continuous load per-... 

Total alkalinity is generally the most relevant alkalinity test, especially in FT boilers where the FW has a low silica content. Testing for T alkalinity provides the best correlation with pH, corrosion inhibition, and tendencies for carryover. 

The influence that variations of temperature and levels of atmospheric CO2 and O2 have on chemical weathering are more subtle. Temperature appears to have a direct effect on weathering rate (White and Blum, 1995). The silica concentration of rivers (Meybeck, 1979, 1987) and the alkalinity of ground waters in carbonate terrains (Harmon et al., 1975) are both positively correlated with temperature variations. It is not clear, however, whether temperature-related variations in weathering rates are largely due to variations in vegetational activity that parallel temperature variations. 

In the bile-duct-ligated rat, hepatic mitochondrial lipid peroxides are increased and correlate with serum levels of alkaline phosphatase, bilirubin and alanine aminotransferase (Sokol et al., 1991). Dietary vitamin E deficiency resulted in relatively higher lipid peroxide and bilirubin... 

Elevated alkaline phosphatase is nonspecific and may correlate with liver or bone disease it tends to be elevated in biliary tract disease. 

Badawy et al. (2002) reported that in near neutral and alkaline soils, representative alluvial, desertic and calcareous soils of Egypt, lead activity ranged from 10 677 to 10 4 83 M, and was negatively correlated with soil and soil solution pH. It could be predicted in soil solution from the equation log (Pb2+) = 9.9-2pH. In German noncontaminated soil with 2.3% CaC03 and soil pH 8.5, Zn, Cu and Cd are 1.87, 0.66, and 0.20 pM/L in soil solution, respectively (Helal et al., 1996). 

Prolonged residence in the intestine or urinary bladder lumen could allow time for significant reaction with tissue components however, N-glucuronyloxy-AAF was only weakly carcinogenic at local subcutaneous sites of application (89). Enzymatic deacetylation to N-glucuronyloxy-AF has been detected in hepatic tissue but this activity in different species does not correlate with their relative susceptibility to AAF hepatocarcinogenesis (94). On the other hand, the alkaline pH-induced conversion to a reactive derivative may play an important role in urinary bladder carcinogenesis (87) by AAF and other arylamides in those species or individuals where normal urine pH is alkaline (e.g. normal rabbit urine pH is 8.5-9.0). 

Yanovskaya and coworkers55 have reported rate constants for the alkaline hydrolysis of ethyl lruns,trans-4 -substi tuted 5-phenyl-2,4-pentadienoates in 60% aqueous dioxan giving the values X, log t, H, -2.60 Cl, -2.23 Br, -2.31 N02, -1.83 OMe, -2.61 NMe2, —3.00. Correlation with the CR equation gave as the best regression equation ... 

Biltz-Zen trend have been discussed and represented as a function of a charge transfer atomic parameter which correlates with Pauling s electronegativity. This approach has been successfully employed for groups of binary alloys formed by the alkaline earths and the divalent rare earth elements. 

A comprehensive review of work on the absorption of carbon dioxide by alkaline solutions has been carried out by Danckwerts and Siiarma(43) who applied results of research to the design of industrial scale equipment. Subsequently, Sahay and Sharma(44) showed that the mass transfer coefficient may be correlated with the gas and liquid rates and the gas and liquid compositions by ... 

Response of cane to CMU is variable and may possibly be correlated with the amount of rainfall or soil pH. In the dry (30 to 40 inches of rainfall) alkaline (pH 8) areas of Puerto Rico, where sugar cane is irrigated, damage to cane has... 

Modifications of the arylamino moiety profoundly influence the rate of hydrolysis. Thus, the hydrolysis of N- ace ty 1 -4-am i no be n zo i c acid was ca. 1000-fold slower than that of acetanilide [66]. Sorci and Macalady [67] investigated the influence of ring substitution on the hydrolysis of para-substituted acetanilides (4.104) in alkaline solution and in soil bacteria. No correlation was found between alkaline and biotic hydrolysis, which appeared to be controlled by different physicochemical properties. Bacterial hydrolysis was best correlated with the Van der Waals radius of the substituent, whereas chemical hydrolysis was correlated with the Hammett constant characterizing the electron-withdrawing capacity of the substituent. Other studies confirmed that a correspondence between bacterial and mammalian esterases... 

A comparison of the kinetics of alkaline hydrolysis of methyl, isopropyl and butyl acetates in propan-2-ol-water and t-butanol-water has revealed that the observed effects correlate with solvent structure. ... 

Solvent effects have been investigated in isatin (193) hydrolysis. Results from ethanol-water and acetonitrile-water mixtures revealed that for alkaline hydrolysis log k was correlated with the reciprocal of the dielectric constant. A tetrahedral intermediate (194) is involved, which breaks down to yield the ring-opened amino acid (195). A comparison has been made of the lability of isatin (193) towards diethyl-amine and hydroxide ion, the latter showing the greater effect. ... 

Sr 10-100 ppm 100-5000 ppm In alkaline feldspars of pegmatites. In other occurrences. Marked correlation with Na in comagmatic series (Steele and Smith, 1982). 

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