Equilibrium biological activity

Note the table gives the quantity of oxygen dissolved in sea-water at dirferent temperatures and chlorinities when in equilibrium with a normal atmosphere saturated with water vapour, li thus represents the condition approached by the surface water when biological activity is not excessive. 

Equilibrium, Structural and Biological Activity Studies on [Organotin(IV)]" Complexes... 

The aim of the present work is to survey the results obtained by means of different equilibrium and structural measurements on the complexes formed with the various organotin(IV) cations. The biological activities of parent organotin(IV) and some of the complexes in object are also discussed. In the rest of the chapter, complexes of the organotin(IV) cations will be discussed — in most cases — in the following order ... 

The soil may represent a thin film on the surface of the Earth, but the importance of soils in global biogeochemical cycles arises from their role as the interface between the Earth, its atmosphere, and the biosphere. All terrestrial biological activity is founded upon soil productivity, and the weathering of rocks that helps to maintain atmospheric equilibrium occurs within soils. Soils provide the foundation for key aspects of global biogeochemical cycles. 

On the analogy of the physicochemical relation, one was led to define a biological Hammett equation which related the equilibrium constant of the drug-receptor complex to the electronic a parameters of the substituents (e.g. chlorine, bromine, methyl, ethyl, hydroxyl, carboxyl, acetyl, etc.) of the drug molecule. Since the equilibrium constant of a drug-receptor complex is reflected by the biological activity, this led to the first extrathermodynamic relationship in QS AR ... 

The assessment of reaction kinetics by means of batch tests may be strongly affected by dye adsorption on the biophase and supports. The relevance of the adsorption phenomena of dyes on biophase has been addressed in studies regarding free cells [41], granular support biofilm [24], entrapped cells [11, 18], anaerobic sludge [10,24,31,34] and biological activated carbon (BAC) [42,45,47,48]. They have pointed out that the kinetics may be overestimated if the assessment of the adsorption contribution to the dye removal is not taken into account. Under batch conditions, the dye is fastly split between the liquid phase and the biophase, resulting in a sharp reduction of the dye concentration in the liquid phase until adsorption equilibrium is approached. The rate of dye adsorption must be estimated and ruled out in the kinetic assessment. 

Fig. 11.7 Equilibrium assay using immbolized mouse IgG antigen capturing anti mouse antibody from solution. The dynamic range is 300 1, showing 16% biological activity and an affinity of...

The subsurface generally is an open system. The presence of CO and other gases in the atmosphere affects the partial pressure of gas constiments in the subsurface. For example, carbonate mineral dissolution in a system open to atmospheric COj does not achieve equilibrium. However, higher local subsurface CO concentrations can originate from biological activity and other oxidation processes. 

Table 8.24 lists the main redox exchanges mediated by biological activity and their equilibrium constants at pH = 7. 

Figure 8.29 Sequence of redox equilibria mediated by biologic activity. From W. Stumm and J. J. Morgan (1981), Aquatic Chemistry, copyright 1981 by John Wiley and Sons. Reprinted by permission of John Wiley Sons. The various equilibrium constants are listed in table 8.24.

The solubility of oxygen in rivers and streams depends on various factors, such as temperature, salt concentration, depth, and biological activity. Its solubility equilibrium is 02(g) 02(aq). Compare the dissolved oxygen concentration at 1.0 atm total pressure (0.21 atm partial pressure) with its concentration for pure oxygen at 1.0 atm. 

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