Biological systems, effect

This interface is critically important in many applications, as well as in biological systems. For example, the movement of pollutants tln-ough the enviromnent involves a series of chemical reactions of aqueous groundwater solutions with mineral surfaces. Although the liquid-solid interface has been studied for many years, it is only recently that the tools have been developed for interrogating this interface at the atomic level. This interface is particularly complex, as the interactions of ions dissolved in solution with a surface are affected not only by the surface structure, but also by the solution chemistry and by the effects of the electrical double layer [31]. It has been found, for example, that some surface reconstructions present in UHV persist under solution, while others do not. 

In addition to the effect of biological variabihty in group response for a given exposure dose, the magnitude of the dose for any given individual also determines the severity of the toxic injury. In general, the considerations for dose—response relationship with respect to both the proportion of a population responding and the severity of the response are similar for local and systemic effects. However, if metabohc activation is a factor in toxicity, then a saturation level may be reached. 

Within a series with a fixed hydrophilic head group, detergency increases with increasing carbon chain length, reaches a maximum, and then decreases. This behavior frequentiy reflects a balance between increased surface activity of the monomer and decreased monomer concentration with increased surface activity. Similar effects are seen in surfactants in biological systems. 

Mechanism of action of nanosized (0.005 - 0.02 p.m) powders of ferromagnetics on biological systems is based on effect of magnetic fields created by ferromagnetic microcrystal assemblies and on specific action of every metal added which determined the field of practical application. 

The concentration of salt in physiological systems is on the order of 150 mM, which corresponds to approximately 350 water molecules for each cation-anion pair. Eor this reason, investigations of salt effects in biological systems using detailed atomic models and molecular dynamic simulations become rapidly prohibitive, and mean-field treatments based on continuum electrostatics are advantageous. Such approximations, which were pioneered by Debye and Huckel [11], are valid at moderately low ionic concentration when core-core interactions between the mobile ions can be neglected. Briefly, the spatial density throughout the solvent is assumed to depend only on the local electrostatic poten-... 

The treatment of electrostatics and dielectric effects in molecular mechanics calculations necessary for redox property calculations can be divided into two issues electronic polarization contributions to the dielectric response and reorientational polarization contributions to the dielectric response. Without reorientation, the electronic polarization contribution to e is 2 for the types of atoms found in biological systems. The reorientational contribution is due to the reorientation of polar groups by charges. In the protein, the reorientation is restricted by the bonding between the polar groups, whereas in water the reorientation is enhanced owing to cooperative effects of the freely rotating solvent molecules. 

It should be noted that compounds of this type " have been of interest as models for hydride transfer reductions in biological systems. Van Bergen and Kellogg state clearly their hope, if not expectation, that when ions such as H, Zn , Mg, etc. are com-plexed in the vicinity of the donor, beneficial catalytic effects might be forthcoming . ... 

The lipids found in biological systems are either hydrophobic (containing only nonpolar groups) or amphipathic, which means they possess both polar and nonpolar groups. The hydrophobic nature of lipid molecules allows membranes to act as effective barriers to more polar molecules. In this chapter, we discuss the chemical and physical properties of the various classes of lipid molecules. The following chapter considers membranes, whose properties depend intimately on their lipid constituents. 

A. SlOEL and H. SlOEL (eds.) Metal Ions in Biological Systems, Vol. 34, Mercury and its Effects on the Environment and Biology, Dekker, New York, 1997 604 pp. 

The similarity recognition hypothesis presented here would be applicable to the specific and precise discrimination in chemical and biological systems. It is hoped that this review will serve to stimulate further work on the physicochemical origin of the shape-similarity effect on specific molecular recognition, for example, work on weak interactions specific for the three-dimensional shape of interacting groups. 

Neumann, E. Principles of electric field effects in chemical and biological systems, in Topics in Bioelectrochemistry and Bioenergetics, Vol. 4, (ed.) Milazzo, G., New York, Wiley 1981... 

Statistics in general is a discipline dealing with ideas on description of data, implications of data (relation to general pharmacological models), and questions such as what effects are real and what effects are different Biological systems are variable. Moreover, often they are living. What this means is that they are collections of biochemical reactions going on in synchrony. Such systems will have an intrinsic variation in their output due to the variances in the... 

You should have predicted that the sterols are present in greatest quantity in biological systems. Your knowledge of biology should have enabled you to identify the steroid hormones as being present in lowest concentrations since hormone, in general, are effective at very low concentrations. 

In general, receptor theory uses indirect mathematical models to estimate descriptors of drug effect. These descriptors still must be used with the proviso that biological systems may still modify drug effect in a system-dependent manner and thus predictions of therapeutic effect must be made with caution across different systems. 

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