Mehr Nutzen als Schaden?

Background: Clinical research involving human subjects must be ethically legitimatised by being scientifically valid, satisfying legal norms, and adhering to basic ethical requirements such as informed consent and appropriate risk-benefit ratios. Autonomous institutional review boards (IRB) support researchers in meeting these demands. Methods: We propose and test a systematic approach to the ethical analysis of risks and potential benefits in clinical research involving human subjects. The scheme was applied on all study protocols from the year 2006 presented to the IRB of our medical faculty. Results: 46?% of the 206 analyzed protocols promise some potential direct benefit to study participants. 12?% of the planned research projects offer the chance of benefit for future patients with the same demographic and clinical characteristics as the study participants (??group-benefit??). The reminder of the protocols (42?%) reveal potential benefit only for medicine and science through gaining knowledge of clinical, social, or scientific value. More than minimal risks for research participants were identified in about 53?% of the studies. Our ethical analysis and evaluation resulted in 33 out of 206 protocols (16?%) with an unfavourable and hardly justifiable risk-benefit ratio. Conclusion: The developed taxonomy together with our conceptual framework for comparing and balancing potential research benefit and harm can increase the transparency and facilitate the communication between researchers and IRB members. Clear guidance for the IRBs supports the standardisation and harmonisation of ethical review, advice, and approval procedures.     

Decision-making based on approximate and smoothed Pareto curves

We consider bicriteria optimization problems and investigate the relationship between two standard approaches to solving them: (i) computing the Pareto curve and (ii) the so-called decision maker’s approach in which both criteria are combined into a single (usually nonlinear) objective function. Previous work by Papadimitriou and Yannakakis showed how to efficiently approximate the Pareto curve for problems like Shortest Path, Spanning Tree, and Perfect Matching. We wish to determine for which classes of combined objective functions the approximate Pareto curve also yields an approximate solution to the decision maker’s problem. We show that an FPTAS for the Pareto curve also gives an FPTAS for the decision-maker’s problem if the combined objective function is growth bounded like a quasi-polynomial function. If the objective function, however, shows exponential growth then the decision-maker’s problem is NP-hard to approximate within any polynomial factor. In order to bypass these limitations of approximate decision making, we turn our attention to Pareto curves in the probabilistic framework of smoothed analysis. We show that in a smoothed model, we can efficiently generate the (complete and exact) Pareto curve with a small failure probability if there exists an algorithm for generating the Pareto curve whose worst-case running time is pseudopolynomial. This way, we can solve the decision-maker’s problem w.r.t. any non-decreasing objective function for randomly perturbed instances of, e.g. Shortest Path, Spanning Tree, and Perfect Matching.     

Synthese substituierter 1, 4-Divinylbenzole durch doppelte Heck-Reaktion mit Ethen unter Druck

Substituted 1,4-divinylbenzenes 3a – i were synthesized by twofold Heck coupling from the corresponding 1,4-dibromo) (electron withdrawing substituents) or 1,4-di-iododialkoxybenzenes 1a – i and ethene. Oligomerizations could be suppressed by increasing the pressure of ethene to 30 bar, simultaneously improving the yields of the title compounds.