Physicochemical factor

Physticochemical coiiatrainla Further constraints can be imposed on the atoms and bonds of the reaction center, such as those physicochemical factors calculated by the PETRA package (see Section 7.1). For example, the partial charges calculated by the PEOE method can be used to extract the chemically feasible reaction from the two conceivable ones as illustrated in Figure 10.3-11. 

Due to the combining effects of hydrodynamic and physicochemical factors, the study of cake structure and resistance is extremely complex, and any mathematical description based on theoretical considerations is at best only descriptive. 

The influence of physicochemical factors is closely related to surface phenomena at the solid-liquid boundary. It is especially manifested by the presence of small particles in the suspension. Large particle sizes result in an increase in the relative influence of hydrodynamic factors, while smaller sizes contribute to a more dramatic influence from physicochemical factors. No reliable methods exist to predict when the influence of physicochemical factors may be neglected. However, as a general rule, for rough evaluations their influence may be assumed to be most pronounced in the particle size range of 15-20 tm. 

Surging and Carryover and Steam-Water Interface Physicochemical Factors... 

Such a model should be as simple as possible, without however missing any of the underlying thermodynamic and physicochemical factors which cause electrochemical promotion. In particular it will be shown that even the use of Langmuir-type adsorption isotherms, appropriately modified due to the application of potential (or equivalently by the presense of promoters) suffice to describe all the experimentally observed rules G1 to G7 as well as practically all other observations regarding electrochemical promotion including the effect of potential on heats of adsorption as well as on kinetics and reaction orders. 

Rosenqvist, I. T. (1962). The influence of physicochemical factors upon the mechanical properties of clays. Proc. 9th Nat. Conf. on Clays and Clay Minerals, pp. 12-27. 

New experimental techniqnes for the direct measurement of interparticle forces are now available and can be nsed to nnderstand the physicochemical factors that control adhesion, coating phenomena, tribology, and others. 

Commercial program packages that either propose phenomenological models or fit a given model to data are easily available such equations, along with the found coefficients can be entered into program TESTFIT. It is strictly forbidden to associate the found coefficients with physicochemical factors unless there is a theoretical basis for a particular model. 

When bacteria or almost any organism are exposed to high temperatures, the synthesis of a set of HSPs encoded by heat shock genes is rapidly and transiently induced this reaction has been designated as the heat shock response. Later, it was foimd that most heat shock genes are not only induced by heat, but by many other stress regimens (Table 1). The stress factors have been classified into three groups physicochemical factors, metabolically harmful substances and complex metaboHc processes. Therefore, the heat shock is often called the stress shock to comply with these observations. 

Regulation of the overall flux through a pathway is important to ensure an appropriate supply, when required, of the products of that pathway. Regulation is achieved by control of one or more key reactions in the pathway, catalyzed by regulatory enzymes. The physicochemical factors that control the rate of an... 

D. Physicochemical Factors Affecting Structure-Permeability Relationships... 

K0/w as measured in the rat intestine [15,16], As with other examples that are available, as K0/w increases, the rate of absorption increases. One very extensive study [17-19] has examined in depth the physicochemical factors governing nonelectrolyte permeability for several hundred compounds. This study employed an in vitro preparation of rabbit gallbladder, an organ whose mucosal surface is lined by epithelial cells. The... 

J. W. Poole, G. Owen, J. Silverio, J. N. Freyhot, and S. B. Roseman, Physicochemical factors influencing the absorption of the anhydrous and trihydrate forms of ampicillin, Curr. Ther. Res., 10, 292-303 (1968). 

MJ Clarke, MJ Tobyn, TN Staniforth. Physicochemical factors governing the performance of nedocromil sodium as a dry powder aerosol. J Pharm Sci 89(9) 11601-1169, 2000. 

S. Feldman, Physicochemical factors influencing drug absorption from the intramuscular site, Bull. Parenter. Drug. Assoc., 28, 53-63 (1974). 

B. Physicochemical Factors Influencing Oral Sustained-Release Dosage Form Design... 

RD Schoenwald, HS Huang. (1983). Corneal penetration behavior of beta-blocking agents. I Physicochemical factors. J Pharm Sci 72 1266-1272. 

In reviewing the pH-partition hypothesis, it is apparent that it is an oversimplification of a very complex process. It does not consider one of the critical physicochemical factors, solubility. Low aqueous solubility is often the cause of the low bioavailability. To address this issue, Dressman et al. [28] developed an absorption potential concept that takes into account not only the partition coefficient but also solubility and dose. Using a dimensional analysis approach, the following simple equation was proposed ... 

SCHOENWALD, R. D. AND HuANG, H.-S., Comeal penetration behavior of beta-blocking agents I Physicochemical factors., J. Pharm. Sci.,... 

Bioavailability of soil-sorbed organic chemicals depends on a variety of physicochemical factors as well as the characteristics of microorganisms involved. Although many studies have provided insight to our understanding of the bioavailability issue, simple correlations have not been found between bioavailability and physicochemical properties of sorbed chemicals or sorbents, nor microbial characteristics. 

Selenium metabolism and degradation are significantly modified by interaction with heavy metals, agricultural chemicals, microorganisms, and a variety of physicochemical factors. 

KEYWORDS heavy metal, physicochemical factors, soil, rice, bio-accumulation coefficient, Zhejiang... 

Physicochemical factors influencing rice s BAC of heavy metals... 

In summary, the bioavailability and observed toxicity of synthetic pyrethroids in sediment-water systems is influenced by a number of physicochemical factors, including the quantity and type of organic and inorganic matter in sediment and in water, as well as by temperature. The use of equilibrium partitioning calculations can be a useful tool for estimating the dissolved and potentially bioavailable fraction of pyrethroids. 

The article Caffeine in coffee its removal why and how by K. Ramalakshmi and B. Raghavan in Critical Reviews in Food Science and Nutrition, 1999, 39, 441 provides an in-depth survey of the physicochemical factors underlying decaffeination of coffee with supercritical CO2. 

Our current, broader picture of the physicochemical factors governing the chemical behaviour of ORMOSIL reveals that chemical modification of the soRcage does indeed alter the chemical properties of the entrapped dopant.11 Learning to master this interaction for different... 

Many of the nonactive, ingredient-related physicochemical factors that influence irritation (tonicity, pH, and particle size, for example) also act to determine blood compatibility. But the chemical features of a drug entity itself, its molecular size and reactivity, can also be of primary importance. 

Kerberle, H. (1971). Physicochemical factors of drugs affecting absorption, distribution and excretion. Acta Pharmacol. Toxicol. 29 (Suppl 3) 30-47. 

The interfacial microenvironment around a microbial community, that is the sum of the physical, chemical, and biological parameters which affect a microorganism, determines whether a particular microorganism will survive and/or metabolize. The occurrence and abundance of microorganisms in an environment are determined by nutrient availability, and various physicochemical factors such as pH, redox potential, temperature, and solid phase texture and moisture. Because a limitation imposed by any one of these factors can inhibit biodegradation, the cause of the persistence of a pollutant is sometimes difficult to pinpoint. The summary follows [39,92,94,97,109,110,172,173,176,189,190, 195,248-252,256-300]. 

Kimura T, Sudo K, Kanzaki Y, Miki K, Takeichi Y, Kurosaki Y, Nakayama T (1994) Drug absorption from large intestine physicochemical factors governing drug absorption. Biol Pharm Bull 17 327-333... 

---