High pH, 26,

In the crystallization of these hydrated salts from aqueous solutions it is essential that a low pH (high level of acidity) is maintained, otherwise hydrolysis occurs and yellow impurities contaminate the products. Similarly, if the salts are redissolved in water, the solutions turn yellow/brown. The hydrolytic processes are complicated, and, in the presence of anions with appreciable coordinating tendencies, are further confused by displacement of water from the coordination sphere of the iron. However, in aqueous solutions of salts such as the perchlorate the following equilibria are important ... 

Micro-organisms with resistance to environmental stresses such as solvents, extremes of pH, high salt concentration, and having broad temperature and dissolved oxygen optima are more suited to process applications. Improved process instrumentation and... 

Sodium hypochlorite is usually sold in solution in water, where it makes a greenish-yellow liquid. (It is too hygroscopic—it absorbs water from the air—to be used conveniently in solid form.) Household bleaches usually contain sodium hypochlorite in a 3 percent to 6 percent solution. Some sodium hydroxide (lye) is added to keep the pH high to avoid decomposition. If the solution is made more acidic, sodium hypochlorite will dissociate, producing chlorine gas and oxygen. 

Several active geothermal systems in Japanese Islands are associated with precious- and base-metal mineralization. Base metal mineralization takes place from hot springs containing high chloride concentration probably due to the contribution of seawater. Precious-metal mineralization occurs in the Osorezan hot springs which are characterized by neutral pH, high H2S concentration, and low salinity. These chemical features are similar to those of epithermal precious metal vein-type deposits in Japan. 

Since mild activation conditions appear to be important, a number of solution activation conditions were tested. PAMAM dendrimers are comprised of amide bonds, so the favorable conditions for refro-Michael addition reactions, (low pH, high temperature and the presence of water) may be able to cleave these bonds. Table 1 shows a series of reaction tests using various acid/solvent combinations to activate the dendrimer amide bonds. Characterization of the solution-activated catalysts with Atomic Absorption spectroscopy, FTIR spectroscopy and FTIR spectroscopy of adsorbed CO indicated that the solution activation generally resulted in Pt loss. Appropriate choice of solvent and acid, particularly EtOH/HOAc, minimized the leaching. FTIR spectra of these samples indicate that a substantial portion of the dendrimer amide bonds was removed by solution activation (note the small y-axis value in Figure 4 relative... 

That which we call a rose, by any other name would smell as sweet. The essence of the denatured state, in contrast, is rather more elusive. The difficulty stems, at least in part, from the wide variety of methods of inducing a protein to unfold. Some proteins appear to be natively unfolded that is, they remain unfolded in the cell under conditions in which they retain their biological activity (Plaxco and Gross, 1997 Wright and Dyson 1999 Dunker, 2002). Other proteins unfold only under the influence of changes in pH, high or low temperatures, or... 

Slater MD, Murphy CR. Co-expression of interleukin-6 and human growth hormone in apparently normal prostate biopsies that ultimately progress to prostate cancer using low pH, high temperature antigen retrieval. /. Mol. Histol. 2006 37 37-41. 

Reconnaissance studies have shown that surface waters originating from waste rock and tailings dumps are typically characterized by low pH, high sulfate levels and variable metal contents. Consequently, the aim of this study is to investigate the nature of ground water interactions with... 

Elution step Specific elution conditions (extreme pH. high salinity, organic solvents, etc.) lo dissociate the complex are usually required. 

Enzymes of the pepsin family rarely catalyze the hydrolysis of esters, with the exceptions of, for example, esters of L-/3-penicillactic acid and some sulfinic acid esters. Under suitable conditions, i. e., low pH, high enzyme concentration, and formation of an insoluble peptide, aspartic peptidases are able to catalyze the synthesis of peptides [71] [72],... 

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