University of Rennes

About: University of Rennes is a education organization based out in Rennes, France. It is known for research contribution in the topics: Population & Catalysis. The organization has 18404 authors who have published 40374 publications receiving 995327 citations.

Two-Dimensional Halide Perovskites Incorporating Straight Chain Symmetric Diammonium Ions, (NH3CmH2mNH3)(CH3NH3)n−1PbnI3n+1 (m = 4–9; n = 1–4)

Abstract: Low-dimensional halide perovskites have recently attracted intense interest as alternatives to the three-dimensional (3D) perovskites because of their greater tunability and higher environmental stability Herein, we present the new homologous 2D series (NH3CmH2mNH3)(CH3NH3)n−1PbnI3n+1 (m = 4–9; n = 1–4), where m represents the carbon-chain number and n equals layer-thickness number Multilayer (n > 1) 2D perovskites incorporating diammonium cations were successfully synthesized by the solid-state grinding method for m = 4 and 6 and by the solution method for m = 7–9 Structural characterization by single-crystal X-ray diffraction for the m = 8 and m = 9 series (n = 1–4) reveals that these compounds adopt the Cc space group for even n members and Pc for odd n members The optical bandgaps are 215 eV for two-layer (n = 2), 201 eV for three-layer (n = 3), and 190 eV for four-layer (n = 4) The materials exhibit excellent solution processability, and casting thin-films of the n = 3 members was successfull

The concept of mechanism from a realist approach: a scoping review to facilitate its operationalization in public health program evaluation

Abstract: Background: Public health interventions are complex by nature, and their evaluation requires unpacking their intervention logic and their interactions with open social systems. By focusing on the interrelationships between context, mechanism, and outcome, Pawson and Tilley's realist approach appears a promising innovation for public health-related evaluation works. However, and as expected of any methodological innovation, this approach is being constructed gradually by answering the multiple challenges to its operationalization that fall in its path. One of these challenges, users of this approach agree on, is the necessity of clarifying its key concept of mechanism. Method: We first collected the definitions of mechanism from published works of Pawson and colleagues. Secondly, a scoping review was conducted to identify the ones quoted by users of the realist approach for evaluating public health interventions (1997–2012). We then appraised the clarity and precision of this concept against the three dimensions defined by Daigneault and Jacobs " term, sense and referent. " Results: Of the 2344 documents identified in the scoping review, 49 documents were included. Term: Users of the realist approach use adjectives qualifying the term mechanism that were not specifically endorsed by Pawson and colleagues. Sense: None of the attributes stated by Pawson and colleagues has been listed in all of the documents analyzed, and some contributions clarified its attributes. Referent: The concept of mechanism within a realist approach can be ascribed to theory-based evaluation, complex social interventions, and critical realism. Conclusion: This review led us to reconsider the concept of mechanism within the realist approach by confronting the theoretical stance of its proponents to the practical one of its users. This resulted in a clearer, more precise definition of the concept of mechanism which may in turn trigger further improvements in the way the realist approach is applied in evaluative practice in public health and potentially beyond. A mechanism is hidden but real, is an element of reasoning and reactions of agents in regard to the resources available in a given context to bring about changes through the implementation of an intervention, and evolves within an open space-time and social system of relationships.

A Graph-Type Extension of Farrell Technical Efficiency Measure

Abstract: We have two goals we wish to accomplish in this article. The first is the development of a framework for measuring efficiency in the full input–output space. This approach introduces a graph-type extension of the Farrell measure of technical efficiency. The second is the introduction of a weighting scheme for inputs and outputs, taking account of the particularity of the market summarized by input and output prices.

The NLRP3 inflammasome is activated by nanoparticles through ATP, ADP and adenosine

Abstract: The NLR pyrin domain containing 3 (NLRP3) inflammasome is a major component of the innate immune system, but its mechanism of activation by a wide range of molecules remains largely unknown. Widely used nano-sized inorganic metal oxides such as silica dioxide (nano-SiO2) and titanium dioxide (nano-TiO2) activate the NLRP3 inflammasome in macrophages similarly to silica or asbestos micro-sized particles. By investigating towards the molecular mechanisms of inflammasome activation in response to nanoparticles, we show here that active adenosine triphosphate (ATP) release and subsequent ATP, adenosine diphosphate (ADP) and adenosine receptor signalling are required for inflammasome activation. Nano-SiO2 or nano-TiO2 caused a significant increase in P2Y1, P2Y2, A2A and/or A2B receptor expression, whereas the P2X7 receptor was downregulated. Interestingly, IL-1β secretion in response to nanoparticles is increased by enhanced ATP and ADP hydrolysis, whereas it is decreased by adenosine degradation or selective A2A or A2B receptor inhibition. Downstream of these receptors, our results show that nanoparticles activate the NLRP3 inflammasome via activation of PLC-InsP3 and/or inhibition of adenylate cyclase (ADCY)-cAMP pathways. Finally, a high dose of adenosine triggers inflammasome activation and IL-1β secretion through adenosine cellular uptake by nucleotide transporters and by its subsequent transformation in ATP by adenosine kinase. In summary, we show for the first time that extracellular adenosine activates the NLRP3 inflammasome by two ways: by interacting with adenosine receptors at nanomolar/micromolar concentrations and through cellular uptake by equilibrative nucleoside transporters at millimolar concentrations. These findings provide new molecular insights on the mechanisms of NLRP3 inflammasome activation and new therapeutic strategies to control inflammation.