Effect of Industrial Heat Treatment and Barrel Finishing on the Mechanical Performance of Ti6Al4V Processed by Selective Laser Melting

Additive manufacturing is now capable of delivering high-quality, complex-shaped metallic components. The titanium alloy Ti6Al4V is an example of a printable metal being broadly used for advanced structural applications. A sound characterization of static mechanical properties of additively manufactured material is crucial for its proper application, and here specifically for Ti6Al4V. This includes a complete understanding of the influence of postprocess treatment on the material behavior, which has not been reached yet. In the present paper, the postprocess effects of surface finish and heat treatment on the mechanical performance of Ti6Al4V after selective laser melting were investigated. Some samples were subjected to barrel finishing at two different intensities, while different sets of specimens underwent several thermal cycles. As a reference, a control group of specimens was included, which did not undergo any postprocessing. The treatments were selected to be effective and easy to perform, being suitable for real industrial applications. Tensile tests were performed on all the samples, to obtain yield stress, ultimate tensile strength and elongation at fracture. The area reduction of the barrel-finished samples, after being tested, was measured by using a 3D scanner, as a further indication of ductility. Experimental results are reported and discussed, highlighting the effect of postprocessing treatments on the mechanical response. We then propose the optimal postprocessing procedure to enhance ductility without compromising strength, for structures manufactured from Ti6Al4V with selective laser melting

Photon number statistics uncover the fluctuations in non-equilibrium lattice dynamics

Fluctuations of the atomic positions are at the core of a large class of unusual material properties ranging from quantum para-electricity to high temperature superconductivity. Their measurement in solids is the subject of an intense scientific debate focused on seeking a methodology capable of establishing a direct link between the variance of the atomic displacements and experimentally measurable observables. Here we address this issue by means of non-equilibrium optical experiments performed in shot-noise limited regime. The variance of the time dependent atomic positions and momenta is directly mapped into the quantum fluctuations of the photon number of the scattered probing light. A fully quantum description of the non-linear interaction between photonic and phononic fields is benchmarked by unveiling the squeezing of thermal phonons in $\alpha$-quartz.Comment: 7 pages (main text), 5 figures, 11 pages (supplementary information

Bioactive silicon nitride: A new therapeutic material for osteoarthropathy

While the reciprocity between bioceramics and living cells is complex, it is principally governed by the implant's surface chemistry. Consequently, a deeper understanding of the chemical interactions of bioceramics with living tissue could ultimately lead to new therapeutic strategies. However, the physical and chemical principles that govern these interactions remain unclear. The intricacies of this biological synergy are explored within this paper by examining the peculiar surface chemistry of a relatively new bioceramic, silicon nitride (Si3N4). Building upon prior research, this paper aims at obtaining new insights into the biological interactions between Si3N4 and living cells, as a consequence of the off-stoichiometric chemical nature of its surface at the nanometer scale. We show here yet unveiled details of surface chemistry and, based on these new data, formulate a model on how, ultimately, Si3N4 influences cellular signal transduction functions and differentiation mechanisms. In other words, we interpret its reciprocity with living cells in chemical terms. These new findings suggest that Si3N4 might provide unique new medicinal therapies and effective remedies for various bone or joint maladies and diseases

Raman Molecular Fingerprints of Rice Nutritional Quality and the Concept of Raman Barcode

The nutritional quality of rice is contingent on a wide spectrum of biochemical characteristics, which essentially depend on rice genome, but are also greatly affected by growing/environmental conditions and aging during storage. The genetic basis and related identification of genes have widely been studied and rationally linked to accumulation of micronutrients in grains. However, genetic classifications cannot catch quality fluctuations arising from interannual, environmental, and storage conditions. Here, we propose a quantitative spectroscopic approach to analyze rice nutritional quality based on Raman spectroscopy, and disclose analytical algorithms for the determination of: (i) amylopectin and amylose concentrations, (ii) aromatic amino acids, (iii) protein content and structure, and (iv) chemical residues. The proposed Raman algorithms directly link to the molecular composition of grains and allow fast/non-destructive determination of key nutritional parameters with minimal sample preparation. Building upon spectroscopic information at the molecular level, we newly propose to represent the nutritional quality of labeled rice products with a barcode specially tailored on the Raman spectrum. The Raman barcode, which can be stored in databases promptly consultable with barcode scanners, could be linked to diet applications (apps) to enable a rapid, factual, and unequivocal product identification based on direct molecular screening

Le projet symogih.org, un système modulaire de gestion de l'information historique

International audienceLe projet symogih.org a conçu une plateforme modulaire et ouverte pour héberger les informations géo-historiques. La plateforme, accessible par le web, permet aux chercheurs de partager leurs données et leurs textes dans un environnement collaboratif et de produire ainsi des données structurées concernant tous les champs historiques.La richesse et l'hétérogénéité de l'information partagée requiert un modèle générique de données qui a été conçu avec la méthode Merise et intégré dans une base de données relationnelles PostgreSQL à laquelle les utilisateurs se connectent par une application web. En parallèle, le projet symogih.org a déployé un environnement pour analyser, partager et publier des textes encodés en XML/TEI en utilisant la plateforme eXist-db. L'annotation sémantique des entités nommées et des unités de connaissance est accomplie en reliant les balises sémantiques définies en ligne avec la Text Encoding Initiative (TEI) aux ressources créées dans la base de données relationnelles.L'ensemble du système est interopérable et en cours d'alignement avec d'autres ressources du web des données et référentiels d'autorité. Une portion croissante des informations sont accessibles au format RDF par un point d'accès SPARQL par un point d'accès SPARQL, permettant une interrogation des données du projet symogih.org et, en même temps, de celles issues d'autres entrepôts du web des données

An Investigation into Quality of Care at the Time of Birth at Public and Private Sector Maternity Facilities in Uttar Pradesh, India

Background: Ensuring high quality care during labour and childbirth is important to eliminate preventable maternal deaths, neonatal deaths and intrapartum stillbirths. My PhD investigates quality of care (QoC) during normal labour and childbirth, and examines whether QoC is influenced by management practices at 26 public and private sector maternity facilities in Uttar Pradesh, India. Methods: First, I conducted clinical observations of labour and childbirth. I used descriptive statistics and multivariate analysis techniques to describe and compare differences in overall QoC, and quality for obstetric and neonatal care. Second, I used quantitative and qualitative methods to describe existing patterns of mistreatment encountered by women. Third, I described existing management practices using a separate survey dataset and linked both QoC and management datasets to examine the relationship between management practices and QoC. Results: QoC was found to be poor at both public and private sector facilities. The private sector outperformed public sector facilities for overall essential care at birth, and for both obstetric and newborn care. All women encountered at least one indicator of mistreatment. There were no significant differences between qualified and unqualified personnel for QoC and mistreatment levels. Qualitative results suggest that informal payments are widespread, maternity care pathways are non-functional, and there are poor hygiene standards. Lastly, I found that maternity facilities scored poorly on management best practices. Overall, I found no association between total management scores and QoC. Conclusions: The results of my PhD study indicate that in 2015, in maternity facilities of Uttar Pradesh, unqualified personnel provided the bulk of maternity care, adherence to evidencebased obstetric and neonatal care protocols was generally poor and all women encountered at least one practice of mistreatment. These results suggest the need to comprehensively measure and urgently improve QoC at the time of birth in Uttar Pradesh, India

Prevalence, associated factors and outcomes of pressure injuries in adult intensive care unit patients: the DecubICUs study

Funder: European Society of Intensive Care Medicine; doi: http://dx.doi.org/10.13039/501100013347Funder: Flemish Society for Critical Care NursesAbstract: Purpose: Intensive care unit (ICU) patients are particularly susceptible to developing pressure injuries. Epidemiologic data is however unavailable. We aimed to provide an international picture of the extent of pressure injuries and factors associated with ICU-acquired pressure injuries in adult ICU patients. Methods: International 1-day point-prevalence study; follow-up for outcome assessment until hospital discharge (maximum 12 weeks). Factors associated with ICU-acquired pressure injury and hospital mortality were assessed by generalised linear mixed-effects regression analysis. Results: Data from 13,254 patients in 1117 ICUs (90 countries) revealed 6747 pressure injuries; 3997 (59.2%) were ICU-acquired. Overall prevalence was 26.6% (95% confidence interval [CI] 25.9–27.3). ICU-acquired prevalence was 16.2% (95% CI 15.6–16.8). Sacrum (37%) and heels (19.5%) were most affected. Factors independently associated with ICU-acquired pressure injuries were older age, male sex, being underweight, emergency surgery, higher Simplified Acute Physiology Score II, Braden score 3 days, comorbidities (chronic obstructive pulmonary disease, immunodeficiency), organ support (renal replacement, mechanical ventilation on ICU admission), and being in a low or lower-middle income-economy. Gradually increasing associations with mortality were identified for increasing severity of pressure injury: stage I (odds ratio [OR] 1.5; 95% CI 1.2–1.8), stage II (OR 1.6; 95% CI 1.4–1.9), and stage III or worse (OR 2.8; 95% CI 2.3–3.3). Conclusion: Pressure injuries are common in adult ICU patients. ICU-acquired pressure injuries are associated with mainly intrinsic factors and mortality. Optimal care standards, increased awareness, appropriate resource allocation, and further research into optimal prevention are pivotal to tackle this important patient safety threat

Correction to: Prevalence, associated factors and outcomes of pressure injuries in adult intensive care unit patients: the DecubICUs study

The original version of this article unfortunately contained a mistake