Direct observation of individual hydrogen atoms at trapping sites in a ferritic steel.

The design of atomic-scale microstructural traps to limit the diffusion of hydrogen is one key strategy in the development of hydrogen-embrittlement-resistant materials. In the case of bearing steels, an effective trapping mechanism may be the incorporation of finely dispersed V-Mo-Nb carbides in a ferrite matrix. First, we charged a ferritic steel with deuterium by means of electrolytic loading to achieve a high hydrogen concentration. We then immobilized it in the microstructure with a cryogenic transfer protocol before atom probe tomography (APT) analysis. Using APT, we show trapping of hydrogen within the core of these carbides with quantitative composition profiles. Furthermore, with this method the experiment can be feasibly replicated in any APT-equipped laboratory by using a simple cold chain.

Quantification of oxide particle composition in model oxide dispersion strengthened steel alloys.

Oxide dispersion strengthened ferritic steels (ODS) are being considered for structural components of future designs of fission and fusion reactors because of their impressive high-temperature mechanical properties and resistance to radiation damage, both of which arise from the nanoscale oxide particles they contain. Because of the critical importance of these nanoscale phases, significant research activity has been dedicated to analysing their precise size, shape and composition (Odette et al., Annu. Rev. Mater. Res. 38 (2008) 471-503 [1]; Miller et al., Mater. Sci. Technol. 29(10) (2013) 1174-1178 [2]). As part of a project to develop new fuel cladding alloys in India, model ODS alloys have been produced with the compositions, Fe-0.3Y2O3, Fe-0.2Ti-0.3Y2O3 and Fe-14Cr-0.2Ti-0.3Y2O3. The oxide particles in these three model alloys have been studied by APT in their as-received state and following ion irradiation (as a proxy for neutron irradiation) at various temperatures. In order to adequately quantify the composition of the oxide clusters, several difficulties must be managed, including issues relating to the chemical identification (ranging and variable peak-overlaps); trajectory aberrations and chemical structure; and particle sizing. This paper presents how these issues can be addressed by the application of bespoke data analysis tools and correlative microscopy. A discussion follows concerning the achievable precision in these measurements, with reference to the fundamental limiting factors.

Ethical issues in haemophilia.

Ethical issues surrounding both the lack of global access to care as well as the implementation of advancing technologies, continue to challenge the international haemophilia community. Haemophilia is not given the priority it deserves in most developing countries. Given the heavy burdens of sickness and disease and severe resource constraints, it may not be possible to provide effective treatment to all who suffer from the various 'orphan' diseases. Nevertheless, through joint efforts, some package of effective interventions can be deployed for a significant number of those who are afflicted with 'orphan' diseases. With cost-effective utilization of limited resources, a national standard of care is possible and affordable. Gene-based diagnosis carries attendant ethical concerns whether for clinical testing or for research purposes, even as the list of its potential benefits to the haemophilia community grows rapidly. As large-scale genetic sequencing becomes quicker and cheaper, moving from the research to the clinic, we will face decisions about the implementation of prenatal, neonatal and other screening programs. Such debates will require input from not just the health care professionals but from all stakeholders in the haemophilia community. Finally, long-term therapeutic success gene transfer in small and large animal models raises the question of when and in which patient population the novel therapeutic approach should first be studied in humans with haemophilia. Although gene therapy represents a worthy goal, the central question for the haemophilia community should be whether it wishes to volunteer itself as a model for a much broader set of innovations.

Equipoise and international human-subjects research.

This paper examines the role of equipoise in evaluating international research. It distinguishes two possible formulations of the equipoise requirement that license very different evaluations of international research proposals. The interpretation that adopts a narrow criterion of similarity between clinical contexts has played an important role in one recent controversy, but it suffers from a number of problems. An alternative interpretation that adopts a broader criterion of similarity does a better job of avoiding both exploitation of the brute fact of social deprivation and the exploitation of needy populations for the benefit of more well-off populations. It also holds out the promise of reconciling the need to find interventions that can be employed in developing world contexts with the cluster of moral values that must constrain the way such research is carried out.

The independence of practical ethics.

After criticizing three common conceptions of the relationship between practical ethics and ethical theory, an alternative modeled on Aristotle's conception of the relationship between rhetoric and philosophical ethics is explored. This account is unique in that it neither denigrates the project of searching for an adequate comprehensive ethical theory nor subordinates practical ethics to that project. Because the purpose of practical ethics, on this view, is to secure the cooperation of other persons in a way that respects their status as free and equal, it seeks to influence the judgments of others by providing them with reasons that are accessible to their own understanding. On this account, the independence of practical ethics is rooted in an appreciation of the constraints that nonideal circumstances place on the role that the philosophically refined premises of moral theory can play in such public deliberations. Practical and philosophical ethics are united, not by shared theoretical frameworks or principles, but by the need to exercise intelligently the same intellectual and affective capacities. They are separated, not by the particularity or generality of their starting points, but by their responsiveness to the practical problem of facilitating sound normative deliberations among persons as we find them, under non-ideal circumstances.

The ambiguity and the exigency: clarifying 'standard of care' arguments in international research.

This paper examines the concept of a 'standard of care' as it has been used in recent arguments over the ethics of international human-subjects research. It argues that this concept is ambiguous along two different axes, with the result that there are at least four possible standard of care arguments that have not always been clearly distinguished. As a result, it has been difficult to assess the implications of opposing standard of care arguments, to recognize important differences in their supporting rationales, and even to locate the crux of the disagreement in some instances. The goal of the present discussion, therefore, is to disambiguate the concept of a 'standard of care' and to highlight the areas of genuine disagreement among different standards. In the end it is argued that one standard of care argument in particular is more complex than either its proponents or its critics may have recognized and that understanding this possibility opens up a potentially promising avenue of inquiry that remains to be carefully explored.

Amenable to reason: Aristotle's rhetoric and the moral psychology of practical ethics.

An Aristotelian conception of practical ethics can be derived from the account of practical reasoning that Aristotle articulates in is Rhetoric and this has important implications for the way we understand the nature and limits of practical ethics. an important feature of this conception of practical ethics is its responsiveness to the complex ways in which agents form and maintain moral commitments, and this has important implications for the debate concerning methods of ethics in applied ethics. In particular, this feature enables us to understand casuistry, narrative, and principlism as mutually supportive modes of moral inquiry, rather than divergent and mutually exclusive methods of ethics. As a result, an Aristotelian conception of practical ethics clears the conceptual common ground upon which practical ethicists can forge a stable and realistic self-understanding.