Degradation modelling

Since it is easier to control and change the conditions of carotenoid studies carried out in model systems, information on degradation kinetics (reaction order model, degradation rate, and activation energy) and products formed are often derived from such studies. 

B. Modeling Degradation, Erosion, and Drug Release Kinetics... 

I can thank just a few of my colleagues and students who helped develop the case studies in this book. John Yecko and William Roy of the Illinois State Geological Survey first modeled degradation of the injection wells at Marshall, Illinois. Rachida Bouhlila provided analyses of the brines at Sebkhat El Melah, Tunisia. 

Next, we tried model degradation by using esterase from microbes. As shown in Fig. 12, the major products under this condition were butylmonosuccinate and butyldisuccinate. This shows that the degradation in early stage is carried out by extracellular enzymes like esterase. 

On the basis of this anti-proteolytic effect of sialic acids, a hypothetical model435 for the role of sialidase in clostridial infections is shown in Scheme 4. It is considered that the bacterial enzyme releases sialic acids from cell-surface glycoproteins of the infected tissue, which thereafter can be readily attacked by proteases. This cooperation between sialidase and protease may support the spreading of the bacteria. Acylneuraminate pyruvate-lyase, also shown in this model, degrades sialic acids for energy supply, and growth, of the bacteria. 

One conclusion from Fig. 15.3 is that our idea to use easily measurable parameters to predict in-situ degradation rates is not principally wrong. However, this survey has demonstrated that existing methods applied in the field studies do not provide a quantitative approach to model degradation rates. One of the major reasons that our attempt failed is the lack of reliable data. Most data sets were incomplete with respect to the relevant redox chemical parameters. In some cases not even the pH was specified... 

Modelling degradation of bioresorbable polymeric medical devices... 

Pan, J., 2015. Modelling Degradation of Bioresorbable Polymeric Medical Devices. Elsevier. 

A series of reduced models are produced based on the activity index and MORA. More specifically, 19, 23, and 37% of the elements are eliminated to generate three reduced models. The accuracy of the reduced models degrades as more elements are eliminated however, even after removing 37% of the elements the reduced model retains only the most important elements to predict the system response with... 

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