Integrated modeling of friction stir welding of 6xxx series Al alloys: Process, microstructure and properties

International audienceCompared to most thermomechanical processing methods, friction stir welding (FSW) is a recent technique which has not yet reached full maturity. Nevertheless, owing to multiple intrinsic advantages, FSW has already replaced conventional welding methods in a variety of industrial applications especially for Al alloys. This provides the impetus for developing a methodology towards optimization, from process to performances, using the most advanced approach available in materials science and thermomechanics. The aim is to obtain a guidance both for process fine tuning and for alloy design. Integrated modeling constitutes a way to accelerate the insertion of the process, especially regarding difficult applications where for instance ductility, fracture toughness, fatigue and/or stress corrosion cracking are key issues. Hence, an integrated modeling framework devoted to the FSW of 6xxx series Al alloys has been established and applied to the 6005A and 6056 alloys. The suite of models involves an in-process temperature evolution model, a microstructure evolution model with an extension to heterogeneous precipitation, a microstructure based strength and strain hardening model, and a micro-mechanics based damage model. The presentation of each model is supplemented by the coverage of relevant recent literature. The "model chain" is assessed towards a wide range of experimental data. The final objective is to present routes for the optimization of the FSW process using both experiments and models. Now, this strategy goes well beyond the case of FSW, illustrating the potential of chain models to support a "material by design approach" from process to performances

In vitro establishment of Salvia hispanica L. plants and callus

El presente trabajo describe la optimización para el establecimiento y mantenimiento de plantas y callos deSalvia hispanica L. (Chia). El establecimiento de los cultivos in vitro se realizó a partir de secciones de tallos.Tanto el AIA como ANA indujeron el desarrollo de raíces adventicias utilizadas a diferentes concentracionessolas o en combinación con citoquininas en condiciones de luz u oscuridad. En oscuridad, la adición de 2,4-D (2.25 μM) indujo el desarrollo de tejido embriogénico, y en iluminación fue promovida la iniciación y elestablecimiento de callos con una alta tasa de crecimiento, los cuales, al principio, fueron verdes pero a lolargo del tiempo fueron perdiendo friabilidad. Por el contrario, cuando se subcultivaron en medio de cultivo MScon las combinaciones de reguladores de crecimiento NAA: kin (0.54 μM:0.46 μM) o Picloram (1.72 μM, 3.43μM) indujeron la formación de callos y mantuvieron su condición de friables por más de dos años. Fue posibledetectar la presencia de aceites esenciales en los callos pero los valores registrados fueron significativamentemenores que en las semillas.Fil: Marconi, Patricia L. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Ciencia y Tecnología Dr. César Milstein (CONICET); ArgentinaFil: López, María C. Instituto Nacional de Tecnología Industrial. INTI-Agroalimentos; ArgentinaFil: De Meester, Jürgen. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Ciencia y Tecnología Dr. César Milstein (CONICET); ArgentinaFil: Bovjin, Celia. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Ciencia y Tecnología Dr. César Milstein (CONICET); ArgentinaFil: Alvarez, María A. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Ciencia y Tecnología Dr. César Milstein (CONICET); Argentin

New primary renal diagnosis codes for the ERA-EDTA

The European Renal Association-European Dialysis and Transplant Association (ERA-EDTA) Registry has produced a new set of primary renal diagnosis (PRD) codes that are intended for use by affiliated registries. It is designed specifically for use in renal centres and registries but is aligned with international coding standards supported by the WHO (International Classification of Diseases) and the International Health Terminology Standards Development Organization (SNOMED Clinical Terms). It is available as supplementary material to this paper and free on the internet for non-commercial, clinical, quality improvement and research use, and by agreement with the ERA-EDTA Registry for use by commercial organizations. Conversion between the old and the new PRD codes is possible. The new codes are very flexible and will be actively managed to keep them up-to-date and to ensure that renal medicine can remain at the forefront of the electronic revolution in medicine, epidemiology research and the use of decision support systems to improve the care of patients

The need for additional care in patients with classical galactosaemia

Purpose: Classical galactosaemia is an inborn error of galactose metabolism which may lead to impairments in body functions and accordingly, need for additional care. The primary aim of this study was to establish the type and intensity of this additional care. Materials and methods: Patients with classical galactosaemia aged >/=2 years were evaluated with the Capacity Profile, a standardised method to classify additional care needs according to type and intensity. Based on a semi-structured interview, current impairments in five domains of body functions were determined. The intensity of additional care was assessed (from 0, usual care, to 5, total dependence). Results: Forty-four patients with classical galactosaemia, 18 males and 26 females (median age 15 years, range 2-49 years), were included. There was a wide spectrum of impairments in mental functions. Motor function impairments were present in four patients, and mild speech impairments in eight patients. Additional care for sensory functions was uncommon. All patients needed a diet, which care is scored in the physical health domain. Conclusions: Apart from the diet all patients need, classical galactosaemia leads to the need for additional care mainly in the domains of mental functions and speech and voice functions. Implications for rehabilitation The Capacity Profile is a useful tool to demonstrate additional care needs in classical galactosaemia. In classical galactosaemia additional care is mostly indicated by mental impairments and speech and voice functions. One-fifth of patients have impairment of speech and voice functions at time of the study, and half of all patients had received speech therapy in childhood. Over 70% of patients need additional care/help due to impairment of mental functions, ranging from coaching due to social vulnerability to full day care

A global agenda for advancing freshwater biodiversity research

Global freshwater biodiversity is declining dramatically, and meeting the challenges of this crisis requires bold goals and the mobilisation of substantial resources. While the reasons are varied, investments in both research and conservation of freshwater biodiversity lag far behind those in the terrestrial and marine realms. Inspired by a global consultation, we identify 15 pressing priority needs, grouped into five research areas, in an effort to support informed stewardship of freshwater biodiversity. The proposed agenda aims to advance freshwater biodiversity research globally as a critical step in improving coordinated actions towards its sustainable management and conservation

The inflammatory potential of diet is associated with the risk of age-related eye diseases

Background &amp; aims: Inflammation is involved in the pathogenesis of cataract, age-related macular degeneration (AMD), and possibly open-angle glaucoma (OAG). We assessed whether the inflammatory potential of diet (quantified using the dietary inflammatory index; DII) affects the incidence of these common blinding age-related eye diseases. Serum inflammation markers were investigated as possible mediators.Methods: Participants aged &gt;45 years were selected from the prospective, population-based Rotterdam Study. From 1991 onwards, every 4–5 years, participants underwent extensive eye examinations. At baseline, blood samples and dietary data (using food frequency questionnaires) were collected. The DII was adapted based on the data available. Of the 7436 participants free of eye diseases at baseline, 4036 developed incident eye diseases during follow-up (cataract = 2895, early-intermediate AMD = 891, late AMD = 81, OAG = 169). Results: The adapted DII (aDII) ranged from −4.26 (i.e., anti-inflammatory) to 4.53 (i.e., pro-inflammatory). A higher aDII was significantly associated with increased inflammation. A higher neutrophil-lymphocyte ratio (NLR) was associated with an increased risk of cataract and AMD. Additionally, complement component 3c (C3c) and systemic immune-inflammation index (SII) were associated with increased risks of cataract and late AMD, respectively. Every point increase in the aDII was associated with a 9% increased risk of cataract (Odds ratio [95% confidence interval]: 1.09 [1.04–1.14]). The NLR and C3c partly mediated this association. We also identified associations of the aDII with risk of AMD (early-intermediate AMD, OR [95% CI]: 1.11 [1.03–1.19]; late AMD, OR [95% CI]: 1.24 [1.02–1.53]). The NLR partly mediated these associations. The aDII was not associated with OAG. Conclusions: A pro-inflammatory diet was associated with increased risks of cataract and AMD. Particularly the NLR, a marker of subclinical inflammation, appears to be implicated. These findings are relevant for patients with AMD and substantiate the current recommendations to strive for a healthy lifestyle to prevent blindness.</p

Strong differences in the clonal variation of two Daphnia species from mountain lakes affected by overwintering strategy

<p>Abstract</p> <p>Background</p> <p>The population structure of cyclical parthenogens such as water fleas is strongly influenced by the frequency of alternations between sexual and asexual (parthenogenetic) reproduction, which may differ among populations and species. We studied genetic variation within six populations of two closely related species of water fleas of the genus <it>Daphnia </it>(Crustacea, Cladocera). <it>D. galeata </it>and <it>D. longispina </it>both occur in lakes in the Tatra Mountains (Central Europe), but their populations show distinct life history strategies in that region. In three studied lakes inhabited by <it>D. galeata</it>, daphnids overwinter under the ice as adult females. In contrast, in lakes inhabited by <it>D. longispina</it>, populations apparently disappear from the water column and overwinter as dormant eggs in lake sediments. We investigated to what extent these different strategies lead to differences in the clonal composition of late summer populations.</p> <p>Results</p> <p>Analysis of genetic variation at nine microsatellite loci revealed that clonal richness (expressed as the proportion of different multilocus genotypes, MLGs, in the whole analysed sample) consistently differed between the two studied species. In the three <it>D. longispina </it>populations, very high clonal richness was found (MLG/N ranging from 0.97 to 1.00), whereas in <it>D. galeata </it>it was much lower (0.05 to 0.50). The dominant MLGs in all <it>D. galeata </it>populations were heterozygous at five or more loci, suggesting that such individuals all represented the same clonal lineages rather than insufficiently resolved groups of different clones.</p> <p>Conclusions</p> <p>The low clonal diversities and significant deviations from Hardy-Weinberg equilibrium in <it>D. galeata </it>populations were likely a consequence of strong clonal erosion over extended periods of time (several years or even decades) and the limited influence of sexual reproduction. Our data reveal that populations of closely related <it>Daphnia </it>species living in relatively similar habitats (permanent, oligotrophic mountain lakes) within the same region may show strikingly different genetic structures, which most likely depend on their reproductive strategy during unfavourable periods. We assume that similar impacts of life history on population structures are also relevant for other cyclical parthenogen groups. In extreme cases, prolonged clonal erosion may result in the dominance of a single clone within a population, which might limit its microevolutionary potential if selection pressures suddenly change.</p

Uveal Melanoma Patients Have a Distinct Metabolic Phenotype in Peripheral Blood

Uveal melanomas (UM) are detected earlier. Consequently, tumors are smaller, allowing for novel eye-preserving treatments. This reduces tumor tissue available for genomic profiling. Additionally, these small tumors can be hard to differentiate from nevi, creating the need for minimally invasive detection and prognostication. Metabolites show promise as minimally invasive detection by resembling the biological phenotype. In this pilot study, we determined metabolite patterns in the peripheral blood of UM patients (n = 113) and controls (n = 46) using untargeted metabolomics. Using a random forest classifier (RFC) and leave-one-out cross-validation, we confirmed discriminatory metabolite patterns in UM patients compared to controls with an area under the curve of the receiver operating characteristic of 0.99 in both positive and negative ion modes. The RFC and leave-one-out cross-validation did not reveal discriminatory metabolite patterns in high-risk versus low-risk of metastasizing in UM patients. Ten-time repeated analyses of the RFC and LOOCV using 50% randomly distributed samples showed similar results for UM patients versus controls and prognostic groups. Pathway analysis using annotated metabolites indicated dysregulation of several processes associated with malignancies. Consequently, minimally invasive metabolomics could potentially allow for screening as it distinguishes metabolite patterns that are putatively associated with oncogenic processes in the peripheral blood plasma of UM patients from controls at the time of diagnosis.</p

Establecimiento in vitro de plantas y callos de Salvia hispanica L.

We have optimized the culture conditions for the initiation and maintenance of Salvia hispanica L. (Chia) plant and callus cultures. Stems section were the best explant source for starting in vitro cultures. Both IAA and NAA, at all the concentration tested with or without the addition of citokinines, have induced the development of adventitious roots both in darkness as in light. In darkness, 2,4-D (2.25 mM) has induced the development of S. hispanica embryogenic tissues and in light promoted the initiation and establishment of green, and fast-growing calli that lost their friability with time. When subcultured to MS culture media with NAA:kin (0.54 mM:0.46 mM) or Picloram (1.72 mM, 3.43 mM) as plant growth regulators, calli maintained friability for two years in culture. It was possible to detect fatty acid content in the calli obtained but the values remained significant lower than those of seeds. Key words: callus induction, chia, micropropagation, plant growth regulatorsEl presente trabajo describe la optimización para el establecimiento y mantenimiento de plantas y callos de Salvia hispanica L. (Chia). El establecimiento de los cultivos in vitro se realizó a partir de secciones de tallos. Tanto el AIA como ANA indujeron el desarrollo de raíces adventicias utilizadas a diferentes concentraciones solas o en combinación con citoquininas en condiciones de luz u oscuridad. En oscuridad, la adición de 2,4-D (2.25 mM) indujo el desarrollo de tejido embriogénico, y en iluminación fue promovida la iniciación y el establecimiento de callos con una alta tasa de crecimiento, los cuales, al principio, fueron verdes pero a lo largo del tiempo fueron perdiendo friabilidad. Por el contrario, cuando se subcultivaron en medio de cultivo MS con las combinaciones de reguladores de crecimiento NAA: kin (0.54 mM:0.46 mM) o Picloram (1.72 mM, 3.43 mM) indujeron la formación de callos y mantuvieron su condición de friables por más de dos años. Fue posible detectar la presencia de aceites esenciales en los callos pero los valores registrados fueron significativamente menores que en las semillas. Palabras clave: Chia, inducción de callos, micropropagación, reguladores de crecimient