Cellular dynamics method

Abstract. Electroanalytical methods are highly compatible with micro- and nano-machining technology and have the potential of invasive but non-destmctive cell analysis. In combination with optical probes and imaging techniques, electroanalytical methods show great potential for the development of multi-analyte detection systems to monitor in real-time cellular dynamics. 

Computational techniques are centrally important at every stage of investigation of nonlinear dynamical systems. We have reviewed the main theoretical and computational tools used in studying these problems among these are bifurcation and stability analysis, numerical techniques for the solution of ordinary differential equations and partial differential equations, continuation methods, coupled lattice and cellular automata methods for the simulation of spatiotemporal phenomena, geometric representations of phase space attractors, and the numerical analysis of experimental data through the reconstruction of phase portraits, including the calculation of correlation dimensions and Lyapunov exponents from the data. 

In spite of the success of CFD simulations for the multiphase turbulent fluid flow in stirred-tank bioreactors (see Section 3.4), their application to coupled material balance equations in case of more complicated reaction networks is still limited by the required computing power. Even in case of successful approaches for model reduction, the number of compounds necessary for reliable portrayal of cellular dynamics in response to spatial variation of extracellular compounds may be still too large. An interesting method to overcome these numerical difficulties is the general hybrid multizonal/CFD [27-36], which gave momentum to the application of CFD modeling for bioreactors. 

In the second section we present a brief overview of some currently used dynamic modeling methods before introducing cellular automata. After a brief history of this method we describe the ingredients that drive the dynamics exhibited by cellular automata. These include the platform on which cellular automata plays out its modeling, the state variables that define the ingredients, and the rules of movement that develop the dynamics. Each step in this section is accompanied by computer simulation programs carried on the CD in the back of the book. 

FRET is an extremely useful phenomenon when it comes to the analysis of molecular conformations and interactions. F or the analysis of interactions, in which two separate molecules are labeled with an appropriate pair of fluorophores, an interaction can be shown by observing FRET. Further, FRET can be used as a type of spectroscopic ruler to measure the closeness of interactions. Proteins, lipids, enzymes, DNA, and RNA can all be labeled and interactions documented. This general method can be applied not only to questions of cellular function like kinase dynamics [3] but also to disease pathways, for example, the APP-PS1 interaction that is important in Alzheimer s disease (AD) [4], Alternatively, two parts of a molecule of interest can be labeled with a donor and acceptor fluorophore. Using this technique, changes in protein conformation and differences between isoforms of proteins can be measured, as well as protein cleavage. 

Nevertheless most of the biophysical methods do not observe single molecules but a huge amount of players in a concentration range between 1014 and 1020 molecules/1 (corresponding to 100 pmol/1 to 1 mmol/1, which are reasonable concentrations in cellular systems). While the dynamics of the single reactants is stochastic the macroscopic readout of the measuring system normally can be described with ordinary differential equations. 

The aforementioned electrical potentials and the electrochemical events involved in the extra-cellular fluid dynamics caused by them around the tumor (viz. coronas) led Nordenstrom to propose the use of externally applied potential differences to cause changes that might lead to the destruction of the tumor, i.e., ECT of cancerous tissues. In 1978, he reported on the treatment of lung metastases in 20 patients by the method of ECT,10 based on earlier preliminary work on five patients. Since then, he has published very extensive studies on the electrochemical treatment (ECT) of tumors.12"18... 

ISO 6721-9 1997 Plastics - Determination of dynamic mechanical properties - Part 9 Tensile vibration - Sonic-pulse propagation method ISO 3385 1989 Flexible cellular polymeric materials - Determination of fatigue by constant-load pounding... 

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