University of Lorraine

About: University of Lorraine is a education organization based out in Nancy, France. It is known for research contribution in the topics: Population & Context (language use). The organization has 11942 authors who have published 25010 publications receiving 425227 citations. The organization is also known as: Lorraine University.

Transferability of interventions in health education: a review

Abstract: Health education interventions are generally complex. Their outcomes result from both the intervention itself and the context for which they are developed. Thus, when an intervention carried out in one context is reproduced in another, its transferability can be questionable. We performed a literature review to analyze the concept of transferability in the health education field. Articles included were published between 2000 and 2010 that addressed the notion of transferability of interventions in health education. Articles were analyzed using a standardized grid based on four items: 1) terminology used; 2) factors that influenced transferability; 3) capacity of the research and evaluation designs to assess transferability; and 4) tools and criteria available to assess transferability. 43 articles met the inclusion criteria. Only 13 of them used the exact term “transferability” and one article gave an explicit definition: the extent to which the measured effectiveness of an applicable intervention could be achieved in another setting. Moreover, this concept was neither clearly used nor distinguished from others, such as applicability. We highlight the levels of influence of transferability and their associated factors, as well as the limitations of research methods in their ability to produce transferable conclusions. We have tried to clarify the concept by defining it along three lines that may constitute areas for future research: factors influencing transferability, research methods to produce transferable data, and development of criteria to assess transferability. We conclude this review with three propositions: 1) a conceptual clarification of transferability, especially with reference to other terms used; 2) avenues for developing knowledge on this concept and analyzing the transferability of interventions; and 3) in relation to research, avenues for developing better evaluation methods for assessing the transferability of interventions.

Surface oxidation of tin chalcogenide nanocrystals revealed by 119Sn-Mössbauer spectroscopy.

Abstract: Narrow band gap tin(II) chalcogenide (SnS, SnSe, SnTe) nanocrystals are of high interest for optoelectronic applications such as thin film solar cells or photodetectors. However, charge transfer and charge transport processes strongly depend on nanocrystals' surface quality. Using (119)Sn-Mossbauer spectroscopy, which is the most sensitive tool for probing the Sn oxidation state, we show that SnS nanocrystals exhibit a Sn((IV))/Sn((II)) ratio of around 20:80 before and 40:60 after five minutes exposure to air. Regardless of the tin or sulfur precursors used, similar results are obtained using six different synthesis protocols. The Sn((IV)) content before air exposure arises from surface related SnS(2) and Sn(2)S(3) species as well as from surface Sn atoms bound to oleic acid ligands. The increase of the Sn((IV)) content upon air exposure results from surface oxidation. Full oxidation of the SnS nanocrystals without size change is achieved by annealing at 500 °C in air. With the goal to prevent surface oxidation, SnS nanocrystals are capped with a cadmium-phosphonate complex. A broad photoluminescence signal centered at 600 nm indicates successful capping, which however does not reduce the air sensitivity. Finally we demonstrate that SnSe nanocrystals exhibit a very similar behavior with a Sn((IV))/Sn((II)) ratio of 43:57 after air exposure. In the case of SnTe nanocrystals, the ratio of 55:45 is evidence of a more pronounced tendency for oxidation. These results demonstrate that prior to their use in optoelectronics further surface engineering of tin chalcogenide nanocrystals is required, which otherwise have to be stored and processed under inert atmosphere.