Activity in water

This PAG contains 1—2% sulfate as soluble calcium sulfate. Sulfate has been found to make PAG products unstable precipitate forms in less than one week at 50°G. Sulfate, however, has also been seen to increase PAG activity in water clarification and is thus intentionally added in one preparation (24). Precipitated calcium sulfate creates a sludge disposal problem. Typical Al content as AI2O2 of PAG products made from alum is 6 —8%. 

Itai, C. Vaadia, Y. (1971). Cytokinin activity in water-stressed shoots. Plant Physiology, 47, 87-90. 

Murray CN, Kautsky H, Hoppenheit M, et al. 1978. Actinide activities in water entering the northern North Sea. Nature 276 225-230. 

Bare CuOx-supported nanostructures showed some activity in H 2 production from methanol-water mixture under UV-visible irradiation [180]. Ni is also used as a dopant, and small amounts (1 wt.%) of this element in mesoporous titania guarantee good activity in water-methanol mixtures under UV-visible light [181]. Indium-tantalum oxide Ni-doped materials also provided photocatalysts with promising efficiencies for direct water splitting [182]. TiOz nanotubes doped with Ir and Co nanopartides were effective for visible light water splitting even in the absence of... 

S. Kobayashi, S. Nagayama, T. Busujima, Lewis Acid Catalysts Stable in Water. Correlation between Catalytic Activity in Water and Hydrolysis Constants and Exchange Rate Constants for Substitution of Inner-Sphere Water Ligands J. Am. Chern. Soc 1998, 120, 8287-8288. 

Unlike the problems associated with measuring alpha and beta activity in water in the field, the properties of gamma radiation allow it to be measured relatively well in water samples in the field. The standard instrumentation used to measure gamma radiation from water samples in the field is a sodium iodide (Nal) scintillator. 

Comparable to the influence of such structural well-defined macrocycles, cell-free extracts55 as well as antibodies309,310 also show strong catalytic effects. Hence, the use of organic compounds, which are able to form micelles, being active in water and easy to handle could lead to new insights and unexpected results for catalytic Diels-Alder... 

Photodegradation. Schaefer and Dupras (39) reported that emulsifiable formulations of methoprene at 0.1 ppm in water showed a rapid photodissipation in sunlight, whereas the commercial, microencapsulated formulation remained biologically active in water for several days under similar conditions. Aqueous solutions of methoprene undergo very rapid (t, <1 hr) photoequilibration to a mixture (,ui l) of 2E, 4E 2Z, 4E isomers (26, 39). 

The study was an attempt to correlate polymer structure to its activity in water treatment applications. Copolymers of acrylic acid with N-(hydroxyraethyl)-, N-(2-hydroxyethy1)-, and N-(2-hydroxypropyl) acrylamide were prepared. 

The copolymers in this study were all in a 3 1 mole ratio of acrylic acid with N-(hydroxyalkyl)acrylamide. Different mole ratios and other molecular weight ranges may have different testing results. However, by continuing this kind of systematic study, we may be able to understand more about the relationship between polymer structure and its activity in water treatment. Hopefully, it can facilitate in choosing or synthesizing a specific polymer for the desired application. 

Lipases exhibit high catalytic activity in water, an even higher activity in a two-phase system, such as water/water-immiscible organic solvent, and in water-immiscible organic solvents of low water content86-88,90. This allows for the attainment of favorable equilibria in asymmetric hydrolysis and esterification reactions catalyzed by lipases. They are used to their greatest... 

Subtilisin generally shows poor transesterification activity in water-free ionic liquids, but Shah and Gupta [73] studied various approaches to maintaining its activity. The best results-up to 10000 times increase in the initial rate N-acetyl-phenylalanine ethyl ester in [BMIm] [PF6]-were obtained by precipitating and washing with 1-propanol. 

Undoubtedly, while the direct method is more relevant, because the analyte activity in water plasma is actually measured, the reporting on blood sodium, potassium and chloride in terms of concentration in plasma is preferred by medical professionals, whatever method of measurement is used. This is justified by the fact that before ISEs had been invented, sodium, potassium and chloride were all determined by indirect methods, with flame emission spectroscopy (FES) for Na+ and K+, and coulometry for Cl. ... 

Conventional wisdom says that enzymes are active in water and in water only, just as in nature according to these ideas, enzymes immediately deactivate in organic solvents. This picture is wrong for several reasons ... 

Enzymatic transesterifications in organic solvents follow Michaelis-Menten kinetics, and in quite a few cases, the values of v/Ku roughly correlate with the solvent s hydrophobicity (Zaks, 1988a). The dependence of the catalytic activity of the enzyme in organic media on the pH of the aqueous solution from which it was recovered is bell-shaped, with the maximum coinciding with the pH optimum of the enzymatic activity in water. 

Vives-Rego, J., G. Billen, A. Fontigny, and M. Somville. 1985. Free and attached proteolytic activity in water environments. Marine Ecology Progress Series 21 245-249. 

Humic substances are abundant in DOM as well as POM, but the role of phenol oxidases in DOM metabolism has been little studied (Munster and De Haan, 1998). Foreman (1999) found that phenol oxidase activity in water from five contrasting Michigan streams was correlated with phenol concentration and that bacterial production in systems with significant humic DOC input was stimulated by the addition of phenols, suggesting that phenols may be an important growth substrate for some bacterial guilds. 

Ans. The order of catalytic activity in water is the same as the order of acidity. In anhydrous ammonia, a stronger base than water (i.e., a more efficient proton acceptor), all three acids are strong. 

Fernandez A, Lassaletta G, Jimenez VM, Justo A, Gonzalez-Elipe AR, Herrmann JM, Tahiri H, Ait-Ichou Y. Preparation and characterization of Ti02 photocalysts supported on various rigid supports (glass, quartz and stainless steel). Comparative studies of photocatalytic activity in water purification. Appl Catal B Environ 1995 7 49-63. 

The conventional Grignard reaction (Fig. 2, route I) would generate both a stoichiometric amount of halide waste and a stoichiometric amount of metal waste. It also requires multistep synthesis of the halides. On the other hand, an alternative Grignard-type reaction via catalytic C-H activation in water (Fig. 2, route II) would preclude the use of flammable organic solvents and also avoid the wasteful process of drying them. Obviously, it would provide a cleaner solution for organic synthesis and provide a theoretical 100% atom-efficiency. 

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