Unit 731 and moral repair.

Unit 731, a biological warfare research organisation that operated under the authority of the Imperial Japanese Army in the 1930s and 1940s, conducted brutal experiments on thousands of unconsenting subjects. Because of the US interest in the data from these experiments, the perpetrators were not prosecuted and the atrocities are still relatively undiscussed. What counts as meaningful moral repair in this case-what should perpetrators and collaborator communities do decades later? We argue for three non-ideal but realistic forms of moral repair: (1) a national policy in Japan against human experimentation without appropriate informed and voluntary consent; (2) the establishment of a memorial to the victims of Unit 731; and (3) US disclosure about its use of Unit 731 data and an apology for failing to hold the perpetrators accountable.

Enhancing autonomy in paid surrogacy.

The gestational surrogate--and her economic and educational vulnerability in particular--is the focus of many of the most persistent worries about paid surrogacy. Those who employ her, and those who broker and organize her services, usually have an advantage over her in resources and information. That asymmetry exposes her to the possibility of exploitation and abuse. Accordingly, some argue for banning paid surrogacy. Others defend legal permission on grounds of surrogate autonomy, but often retain concerns about the surrogate. In response to the dilemma of a ban versus bald permission, we propose a 'soft law' approach: states should require several hours of education of surrogates--education aimed at informing and enhancing surrogate autonomy.

A difference-matrix metaheuristic for intensity map segmentation in step-and-shoot IMRT delivery.

At an intermediate stage of radiation treatment planning for IMRT, most commercial treatment planning systems for IMRT generate intensity maps that describe the grid of beamlet intensities for each beam angle. Intensity map segmentation of the matrix of individual beamlet intensities into a set of MLC apertures and corresponding intensities is then required in order to produce an actual radiation delivery plan for clinical use. Mathematically, this is a very difficult combinatorial optimization problem, especially when mechanical limitations of the MLC lead to many constraints on aperture shape, and setup times for apertures make the number of apertures an important factor in overall treatment time. We have developed, implemented and tested on clinical cases a metaheuristic (that is, a method that provides a framework to guide the repeated application of another heuristic) that efficiently generates very high-quality (low aperture number) segmentations. Our computational results demonstrate that the number of beam apertures and monitor units in the treatment plans resulting from our approach is significantly smaller than the corresponding values for treatment plans generated by the heuristics embedded in a widely use commercial system. We also contrast the excellent results of our fast and robust metaheuristic with results from an 'exact' method, branch-and-cut, which attempts to construct optimal solutions, but, within clinically acceptable time limits, generally fails to produce good solutions, especially for intensity maps with more than five intensity levels. Finally, we show that in no instance is there a clinically significant change of quality associated with our more efficient plans.