Optimal treatment of cancer diseases

A new optimal control model of chemotherapeutic cancer treatment is presented including both the number of cancer cells and the level of toxicity as state variables. It is shown that under certain conditions, periodic drug administration is optimal. Although the model is highly stylized and too simple to describe realistic chemotherapeutic treatment patterns, it may be seen as a first step to prove that periodic treatment strategies are superior to therapies with monotonic decreasing or increasing dosage rates.     

COPPER INDUCED LIPID OXIDATION DURING SALTING OF COD (GADUS MORHUA L.)

Yellow/brown discoloration of the muscle surface was investigated in downgraded heavily salted cod fillets from a processing plant. The results showed that discolored areas were relatively evenly distributed on the muscle surface and that lipid oxidation correlated with the copper and not the iron content, in the muscle. A model system for studying lipid oxidation and yellow discoloration of salted cod muscle was established and used for investigating the effect of including transition metals in the process. The model system confirms that copper is particularly pro-oxidative. Of the redox states, the reduced form of copper was most potent. It appears that copper concentrates in the muscle during the brining. The results also indicate that copper induced lipid oxidation was increased by low pH of the fish muscle postmortem. The model system seems well suited for detailed studies of the salting process and may be useful for developing methods which can inhibit lipid oxidation in salted products.     

THE USE OF BAYESIAN BELIEF NETS IN SAFETY ASSESSMENT OF SOFTWARE BASED SYSTEMS

The paper describes an investigation of methods to perform a reliability and safety assessment of the software in programmable safety relevant systems. It emphasises in particular how disparate information sources and different quantitative and qualitative methods should be combined in such an assessment. It starts with a general discussion of rule based, probabilistic and expert judgement methods and their applicability on software reliability. Then a method for combining different evidences in a reliability and safety assessment is pinpointed, viz. the Bayesian Belief Net (BBN) methodology. It is also illustrated how this method may be applied for safety assessment of software.