Determination of precipitate strengthening in Al-Cu alloys through micropillar compression: Experiments and multiscale simulations

Al-Cu alloys are efficiently strengthened by different types of precipitates: Guinier-Preston zones, θ\u27\u27 (Al3Cu) and θ\u27 (Al2Cu). The contribution of each type of precipitate to the strengthening of the alloy was determined by means of a high-throughput strategy based on micropillar compression. To this end, an Al-4 wt.% Cu alloy was manufactured by casting, following by several homogenization heat treatments at high temperature. The alloy was aged at 23ºC and 180ºC for different times to produce different precipitate structures [1]. Micropillars were machined using a focus ion beam in grains oriented for single and multiple slip and compressed at ambient temperature. The critical resolved shear stress was determined as a function of the applied strain for micropillars with different sizes oriented for single slip to assess the size effect. It was found that the properties of the bulk crystals could be obtained by testing square micropillars with cross-section \u3e 5 x 5 µm2. In addition, the precipitate type and spatial distribution as well as the mechanisms of dislocation/precipitate interaction were studied in the transmission electron microscope from lamella extracted from the deformed micropillars. It was found that Guinier-Preston zones and small θ\u27\u27 precipitates (\u3c 50 nm) were sheared by dislocations while dislocations formed Orowan loops around large θ\u27 precipitates. Afterwards, the effect of latent hardening for the different types of precipitates was studied by compression of micropillars oriented for double slip (coplanar and non-coplanar) as well as for multiple slip. In parallel, the critical resolved shear stress in the overaged Al-Cu alloys containing large θ\u27 precipitates was simulated by means of dislocation dynamics simulations using the discrete-continuous method in combination with a fast Fourier transform solver to compute the mechanical fields [2]. Simulations took into account the effect of precipitate shape, orientation and volume fraction as well the elastic mismatch between the matrix and the precipitate, the stress-free transformation strain around the precipitate and the dislocation character as well as dislocation cross-slip. In addition, the results of the micropillar compression tests were used to calibrate the latent hardening parameters of a crystal plasticity model, so they can be used to predict the mechanical behavior of polycrystals by means of computational homogenization. Overall, the results of this investigation show how micropillar compression can be used as a high-throughput technique to obtain the bulk properties of precipitation-strengthened alloys as well as to validate the results of simulation strategies at lower length scales (dislocation dynamics) and to provide input information for simulations at larger length scales (computational homogenization of polycrystals). [1] A. Rodríguez-Veiga, B. Bellón, I. Papadimitriou, G. Esteban-Manzanares, I. Sabirov, J. LLorca. A multidisciplinary approach to study precipitation kinetics and hardening in an Al-4wt.%Cu alloy. Journal of Alloys and Compounds, 757, 504-519, 2018. [2] R. Santos-Güemes, G. Esteban-Manzanares, I. Papadimitriou, J. Segurado, L. Capolungo, J. LLorca. Discrete dislocation dynamics simulations of dislocation- θ’ precipitate interaction in Al-Cu alloys. Journal of the Mechanics and Physics of Solids, 118, 228-244, 2018

Qualitative evaluation of a complex intervention to implement health promotion activities according to healthcare attendees and health professionals: EIRA study (phase II)

Objective: To evaluate the implementation and development of a complex intervention on health promotion and changes in health-promoting behaviours in primary healthcare according to healthcare attendees and health professionals. Design: Descriptive qualitative evaluation research conducted with 94 informants. Data collection techniques consisted of 14 semistructured individual interviews, 9 discussion groups, 1 triangular group and 6 documents. Three analysts carried out a thematic content analysis with the support of Atlas.ti software. This evaluation was modelled on Proctor and colleagues’ concept of outcomes for implementation research. Setting: 7 primary care centres from seven Spanish regions: Andalusia, Aragon, Balearic Islands, Basque Country, Castilla-La Mancha, Castilla-Leon and Catalonia. Participants: The study population were healthcare attendees (theoretical sampling) and health professionals (opportunistic sampling) who had participated in the exploratory trial of the EIRA intervention (2015). Results: Healthcare attendees and professionals had a positive perception of the study. Healthcare attendees even reported that they would recommend participation to family and friends. Health professionals became aware of the significance of the motivational interview, especially for health promotion, and emphasised social prescribing of physical activity. They also put forward recommendations to improve recruitment, screening and retention of participants. Healthcare attendees modified behaviours and health professionals modified working practices. To achieve sustainability, health professionals believe that it is crucial to adapt agendas and involve all the staff. Conclusions: The discourses of all stakeholders on the intervention must be taken into consideration for the successful, setting-specific implementation of adequate, acceptable, equitable and sustainable strategies aimed at health promotion and well-being

Qualitative evaluation of a complex intervention to implement health promotion activities according to healthcare attendees and health professionals : EIRA study (phase II)

Altres ajuts: This project has been funded by the Carlos III Health Institute (Ministry of Economy and Competitiveness, Spain) through the Network for Prevention and Health Promotion in Primary Care (redIAPP, RD12/0005/0001; RD16/0007/0001) and by European Union European Regional Development Fund (ERDF) funds (European Regional Development Fund).Objective To evaluate the implementation and development of a complex intervention on health promotion and changes in health-promoting behaviours in primary healthcare according to healthcare attendees and health professionals. Design Descriptive qualitative evaluation research conducted with 94 informants. Data collection techniques consisted of 14 semistructured individual interviews, 9 discussion groups, 1 triangular group and 6 documents. Three analysts carried out a thematic content analysis with the support of Atlas.ti software. This evaluation was modelled on Proctor and colleagues' concept of outcomes for implementation research. Setting 7 primary care centres from seven Spanish regions: Andalusia, Aragon, Balearic Islands, Basque Country, Castilla-La Mancha, Castilla-Leon and Catalonia. Participants The study population were healthcare attendees (theoretical sampling) and health professionals (opportunistic sampling) who had participated in the exploratory trial of the EIRA intervention (2015). Results Healthcare attendees and professionals had a positive perception of the study. Healthcare attendees even reported that they would recommend participation to family and friends. Health professionals became aware of the significance of the motivational interview, especially for health promotion, and emphasised social prescribing of physical activity. They also put forward recommendations to improve recruitment, screening and retention of participants. Healthcare attendees modified behaviours and health professionals modified working practices. To achieve sustainability, health professionals believe that it is crucial to adapt agendas and involve all the staff. Conclusions The discourses of all stakeholders on the intervention must be taken into consideration for the successful, setting-specific implementation of adequate, acceptable, equitable and sustainable strategies aimed at health promotion and well-being

Expression of endoglin isoforms in the myeloid lineage and their role during aging and macrophage polarization

20 p.-6 fig.-3 fig. supl.-2 tab. supl.Endoglin plays a crucial role in pathophysiological processes such as hereditary hemorrhagic telangiectasia (HHT), preeclampsia and cancer. Endoglin expression is upregulated during the monocyte-to-macrophage transition, but little is known about its regulation and function in these immune cells. Two different alternatively spliced isoforms of endoglin have been reported, L-endoglin and S-endoglin. Although L-endoglin is the predominant variant, here, we found that there was an increased expression of the S-endoglin isoform during senescence of the myeloid lineage in human and murine models. We performed a stable isotope labelling of amino acids in cell culture (SILAC) analysis of both L-endoglin and S-endoglin transfectants in the human promonocytic cell line U937. Analysis of differentially expressed protein clusters allowed the identification of cellular activities affected during aging. S-endoglin expression led to decreased cellular proliferation and a decreased survival response to granulocyte-macrophage colony-stimulating factor (GM-CSF)-induced apoptosis, as well as increased oxidative stress. Gene expression and functional studies suggested that there was a non-redundant role for each endoglin isoform in monocyte biology. In addition, we found that S-endoglin impairs the monocytic differentiation into the pro-inflammatory M1 phenotype and contributes to the compromised status of macrophage functions during aging.This study was supported by grants from Ministerio de Economía y Competitividad of Spain [grant number SAF2010-19222 to C.B.]; and Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER) (to C.B.). CIBERER is an initiative of the Instituto de Salud Carlos III (ISCIII) of Spain supported by FEDER funds. M.A. was supported by a fellowship from Ministerio de Ciencia e Innovación [grant number BES-2008-003888].Peer reviewe