Biological transfer models

All of the many biological transfer processes combine to determine a net surface resistance to transfer. Empirical relationships can be used to infer stomatal resistance from data on photosynthetically active radiation, water stress, temperature, atmospheric humidity and carbon dioxide levels. The resulting net surface resistance has been coupled with mathematical descriptions of aerodynamic and boundary-layer resistances in a "big leaf" model derived on the basis of agricultural and forest meteorology literature (4). At present, the big-leaf model is relatively coarse, permitting application only to areas dominated by maize, soybeans, grass, deciduous trees, and conifers. 

Shilov, A. E., and Shteinman, A. A., 1999, Oxygen atom transfer into C6H bond in biological and model chemical systems, mechanistic aspects, Acc. Chem. Res. 32 763n771. 

Data from multi-filter, moderate bandwidth instruments are often post-processed in combination with radiative transfer modeling, which allows the reconstruction of the full solar spectrum. In a second step, the calculated solar spectrum can be weighted with any biological weighting function, i.e. for determination of erythemal doses [19]. 

Several models have been developed in the last decade aimed at describing the emission of volatile organic compounds (VOCs) from indoor materials. These models may be broadly distinguished with respect to their conceptual background (physical-mass transfer models and/or empirical-statistical models) as well as their ability to describe different emission profiles. Physical models are models based on principles of physics and chemistry, whereas the empirical models do not necessarily require fundamental knowledge of the underlying physical, chemical and/or biological mechanisms. Many models used in the indoor air quality field in practice are hybrid models, in which aspects of both physical and empirical approaches are combined. 

The electron transfer model presented here recalls the process of charge transport in semiconductors that is, a conduction band is populated by a thermalized electron, which then moves freely through the semiconductor via wavelike k states. While the possibility of semiconductorlike electron transfer in biological systems was first raised many years ago by DeVault and Chance [93], it has never been found experimentally in fact, there was reasonable skepticism that nature would choose such a mechanism in natural biological systems [84]. The density matrix method allows one to construct a model in which the conditions for such a process can be clarified and investigated in a detailed way. 

The remarkable biological transfer of a methyl group from one metal to another in ACS catalysis has been modeled using a monomeric Ni complex, [ (tmc)]" ". ... 

The construction of energy-transfer model systems by use of noncovalently linked donor-acceptor pairing is also of great interest in that it helps the understanding of biological photochemical behavior. In 1990, Hamilton and coworkers presented the first example of noncovalently linked donor-... 

Pennes Bioheat Transfer Model. It is known that one of the primary functions of blood flow in a biological system is its ability to heat or cool the tissue, depending on the relative local tissue temperature. The existence of a temperature difference between the blood and tissue is taken as evidence of its function to remove or release heat. On the basis of this speculation, Pennes [Pennes, 1948] proposed his famous bioheat transfer model, which is called Pennes bioheat equation. Pennes suggested that the effect of blood flow in the tissue be modeled as as heat source or sink term added to the traditional heat conduction equation. The Pennes bioheat equation is given by... 

Biological proton transfers models are generally based on the expression of the rate constant given by the classical formulation of transition state theory (TST) ... 

The aim of this section is to introduce methods used in the applications described in the following sections and, more generally, to help the non-specialist reader to understand the literature about biological proton transfer models. 

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