Nonspecific hydration

Nonspecific hydration, or hydration of the lattice without first-order phase transitions, also must be considered. Cox et al. [40] reported the moisture uptake profile of cromolyn sodium, and the related effects on the physical properties of this substance. Although up to nine molecules of water per molecule of cromolyn sodium are sorbed into the crystalline lattice at 90% relative humidity, the sorption profile does not show any sharp plateaus corresponding to fixed hydrates. Rather, the uptake profile exhibits a gradual increase in moisture content as relative humidity increases, which results in... 

Fig. 3.16. Hydration shell model (according to Modes et al, 1979a). Hydration of N-methyl-acetamide is shown. iV-Methylacetamide is represented by its cross section. The heavy line delineates the van der Waals contour the thin line surrounding the molecule indicates the boundary of the hydration shell. Two specifically bound water molecules and W2 are shown. Water molecules contained within the boundary contribute to specific and to nonspecific hydration (see text).

An (/ )-stereospecific amidase from B. imperiale B222 was used for the s3mthesis of (/ )-2-arylox3 ropionic acids (compounds with high herbicidal tivity [85]) in almost optically pure form (e.e. 86-95%). During hydrolysis of the corresponding racemic nitriles, the (5)-amides were recovered (e.e, 76-95%). In Fig. 30 only the e.e. values of the unsubstituted amide and acid products are shown. The racemic nitrile substrates were supposed to be quickly and nonselectively hydrated to the amides followed by a slow (/ )-stereospecific amidase reaction [86]. This was supported by the finding of a nonspecific hydration of racemic nitriles by the partially purified nitrile hydratase and an (i )-specific hydrolysis of racemic amides by the partially purified amidase [87]. 

Kinetic inhibitors for hydrate formation may also be effective in preventing scale deposition [1627]. This may be understood in terms of stereospecific and nonspecific mechanisms of scale inhibition. 

Where is the water located (i.e., adsorbed to the external surface of crystals, absorbed into crystals as specific or nonspecific water of hydration, absorbed into amorphous regions, condensed into pores, etc.) ... 

Soy Protein Concentrates. Both non-functional (low or no solubility) and functional (good solubility, emulsification capacity, and dispersibility) soy protein concentrates (70% protein, dry basis) are commercially available for use in meat products (2-4, 6, j), 15) Normally, a highly functional product with no harsh or bitter flavors is desirable. When used to replace lean meat, non-hydrated concentrate can be used at levels up to 6-7% in finished nonspecific emulsion meats Higher replacement levels or formulas with specific cost/nutrition requirements may use soy protein concentrate with a judicious amount of textured soy protein (6). Excellent yields, cost savings, texture, flavor and nutrient profiles are possible. However, most soy protein concentrates lack sufficient solubility or sufficiently low viscosities to be used in brines for absorption or injection into whole muscle tissue. When legal standards for protein content exist (13), more concentrate must be used to achieve legal minimums. Brine viscosities increase and uniform distribution of brine components throughout the specific whole muscle piece is restricted. Finished product appearance and flavor are easily compromised. Thus, use of soy protein concentrates in whole muscle applications is limited. 

Besides thick-layer DNA/GEC surface, a thin-layer DNA/GEC could be achieved by wet-adsorption of ss- and dsDNA and ODN onto a GEC transducer under static conditions [99,100]. In this case, the hydrated B-DNA form was stabilized over the GEC surface by weaker forces. Unlike the GEC surface modified by the thick DNA layer —produced in dry conditions—the thin-layer DNA/GEC surface required blocking treatment to avoid nonspecific... 

Uses Suppress/eluninate bacteriuria associated w/ chronic/recurrent UTI Action Converted to formaldehyde ammonia in acidic urine nonspecific bactericidal action Dose Adults. Hippurate 0.5-1 g bid. Mandelate 1 g qid PO pc hs Peds 6-12 y. Hippurate 25-50 mg/kg/d PO bid. Mandelate 50-75 mg/kg/d PO qid (take w/ food, ascorbic acid w/ adequate hydration) Caution [C, +] Contra Renal insuff, severe hepatic Dz, severe dehydration sulfonamide allergy Disp Tabs SE Rash, GI upset, dysuria, t LFTs EMS Monitor BP for hypovolemia and dehydration OD Sxs unknown symptomatic and supportive... 

KaoUn powder and other hydrated aluminum silicate clays, often combined with pectin (a complex carbohydrate), are the most widely used adsorbent powders (e.g., Kaopectate). Kaolin is a naturally occurring hydrated aluminum silicate that is prepared for medicinal use as a very finely divided powder. The rationale behind its use in acute nonspecific diarrhea stems from its ability to adsorb some of the bacterial toxins that often cause the condition. It is almost harmless and is effective in many cases of diarrhea if taken in large enough doses (2-10 g initially, followed by the same amount after every bowel movement). The adsorbents are generally safe, but they may interfere with the absorption of some drugs from the GI tract. 

Table 6.2 shows the detachment energy of one water molecule from a hydrated halide ion cluster [41]. The strength of the water-halide interactions is reduced as the ionic radius increases in the order of Fspecific adsorption in an electrochemical environment. It is clear that the nonspecific adsorption behavior of F is due to its strongly bound solvation shell. Due to... 

Drugs had long been seen as a means of normalizing consciousness when its perceptual, affective, or emotional balance was tipped in the direction of psychosis and/or disabling anxiety. But prior to 1955, most of the drugs that were tried were nonspecific brain depressants like chloral hydrate, bromine, and the barbiturate sedatives. By reducing the brain s activation level, these drugs reset all of the molecules of consciousness simultaneously and unselectively. 

Next comes a layer of nonspecifically adsorbed counterions with their hydration shell. Still, the permittivity is significantly reduced because the water molecules are not free to rotate. This layer specifies the outer Helmholtz plane. Finally there is the diffuse layer. A detailed discussion of the structure of the electric double layer at a metal surface is included in Ref. [65],... 

Free ions ions that are so well hydrated that they do not interact (except for nonspecific interactions). 

Bunton and coworkers80 also investigated salt and micellar effects on the hydration of 39 and 40 in aqueous HC1. In dilute HC1 ten different added salts produced positive, but relatively modest, effects on reaction rate. These almost nonspecific effects were attributed to the typical ability of strong electrolytes to increase medium acidity. At 1 M HCL, however, the effects were very small or slightly negative for 40. Since this is the region in which kjs-1 reaches a plateau, the result can be attributed to enhancement of the unproductive equilibrium discussed above. 

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