Risk of damage and desiccation cracking of construction materials based on raw earth

Nowadays, structures are mainly constructed using natural aggregates as sand and gravels. In the future, we would increasingly have to consider replacing them by more abundant and ecological natural materials such as raw earth. However, despite its many qualities (low gray energy, thermal and hygrometric isolation), this eco-material has some defects: cracking by desiccation. The later prevent its widespread diffusion. This study aims to understand the mechanisms of appearance and propagation of cracks in order to try to either prevent or repair it. To carry out this study, digital image correlation technique is used. It consists in performing free desiccation tests to follow the initiation and propagation of cracks, from the beginning of homogeneous strain until the appearance of discontinuity, in order to determine the strains tensor in the massif. In order to understand the origin of cracking, desiccation is studied for different boundary conditions and according to different intrinsic characteristics of the material

Transradial approach for diagnostic cerebral angiograms in the elderly: a comparative observational study

Introduction: The transradial approach (TRA) reduces mortality, morbidity, access site complications, hospital cost, and length of stay while maximizing patient satisfaction. We aimed to assess the technical success and safety of TRA for elderly patients (aged ≥75 years). Methods: A retrospective chart review and comparative analysis was performed for elderly patients undergoing a diagnostic cerebral angiogram performed via TRA versus transfemoral approach (TFA). Also, a second comparative analysis was performed among the TRA cohort between elderly patients and their younger counterparts. Results: Comparative analysis in the elderly (TRA vs TFA) showed no significant differences for contrast dose per vessel, fluoroscopy time per vessel, procedure duration, conversion rate, and access site complications. Radiation exposure per vessel was significantly lower in the elderly TRA group. The second comparison (TRA in elderly vs TRA in the young) showed no significant differences for contrast dose per vessel, radiation exposure per vessel, procedure duration, access site complication, and conversation rate. A trend for prolonged fluoroscopy time per vessel was observed in the elderly TRA group. Conclusion/Discussion: TRA is a technically feasible and safe option for diagnostic neurointerventional procedures in the elderly. Our small elderly cohort was not powered enough to show a significant difference in terms of access site complications between TRA and TFA

How does study quality affect the results of a diagnostic meta-analysis?

Background: The use of systematic literature review to inform evidence based practice in diagnostics is rapidly expanding. Although the primary diagnostic literature is extensive, studies are often of low methodological quality or poorly reported. There has been no rigorously evaluated, evidence based tool to assess the methodological quality of diagnostic studies. The primary objective of this study was to determine the extent to which variations in the quality of primary studies impact the results of a diagnostic meta-analysis and whether this differs with diagnostic test type. A secondary objective was to contribute to the evaluation of QUADAS, an evidence-based tool for the assessment of quality in diagnostic accuracy studies. Methods: This study was conducted as part of large systematic review of tests used in the diagnosis and further investigation of urinary tract infection (UTI) in children. All studies included in this review were assessed using QUADAS, an evidence-based tool for the assessment of quality in systematic reviews of diagnostic accuracy studies. The impact of individual components of QUADAS on a summary measure of diagnostic accuracy was investigated using regression analysis. The review divided the diagnosis and further investigation of UTI into the following three clinical stages: diagnosis of UTI, localisation of infection, and further investigation of the UTI. Each stage used different types of diagnostic test, which were considered to involve different quality concerns. Results: Many of the studies included in our review were poorly reported. The proportion of QUADAS items fulfilled was similar for studies in different sections of the review. However, as might be expected, the individual items fulfilled differed between the three clinical stages. Regression analysis found that different items showed a strong association with test performance for the different tests evaluated. These differences were observed both within and between the three clinical stages assessed by the review. The results of regression analyses were also affected by whether or not a weighting (by sample size) was applied. Our analysis was severely limited by the completeness of reporting and the differences between the index tests evaluated and the reference standards used to confirm diagnoses in the primary studies. Few tests were evaluated by sufficient studies to allow meaningful use of meta-analytic pooling and investigation of heterogeneity. This meant that further analysis to investigate heterogeneity could only be undertaken using a subset of studies, and that the findings are open to various interpretations. Conclusion: Further work is needed to investigate the influence of methodological quality on the results of diagnostic meta-analyses. Large data sets of well-reported primary studies are needed to address this question. Without significant improvements in the completeness of reporting of primary studies, progress in this area will be limited

Characterization of greater middle eastern genetic variation for enhanced disease gene discovery

The Greater Middle East (GME) has been a central hub of human migration and population admixture. The tradition of consanguinity, variably practiced in the Persian Gulf region, North Africa, and Central Asia1-3, has resulted in an elevated burden of recessive disease4. Here we generated a whole-exome GME variome from 1,111 unrelated subjects. We detected substantial diversity and admixture in continental and subregional populations, corresponding to several ancient founder populations with little evidence of bottlenecks. Measured consanguinity rates were an order of magnitude above those in other sampled populations, and the GME population exhibited an increased burden of runs of homozygosity (ROHs) but showed no evidence for reduced burden of deleterious variation due to classically theorized ‘genetic purging’. Applying this database to unsolved recessive conditions in the GME population reduced the number of potential disease-causing variants by four- to sevenfold. These results show variegated genetic architecture in GME populations and support future human genetic discoveries in Mendelian and population genetics

Erratum to: 36th International Symposium on Intensive Care and Emergency Medicine

[This corrects the article DOI: 10.1186/s13054-016-1208-6.]

Optimisation of Perioperative Cardiovascular Management to Improve Surgical Outcome II (OPTIMISE II) trial: study protocol for a multicentre international trial of cardiac output-guided fluid therapy with low-dose inotrope infusion compared with usual care in patients undergoing major elective gastrointestinal surgery.

INTRODUCTION: Postoperative morbidity and mortality in older patients with comorbidities undergoing gastrointestinal surgery are a major burden on healthcare systems. Infections after surgery are common in such patients, prolonging hospitalisation and reducing postoperative short-term and long-term survival. Optimal management of perioperative intravenous fluids and inotropic drugs may reduce infection rates and improve outcomes from surgery. Previous small trials of cardiac-output-guided haemodynamic therapy algorithms suggested a modest reduction in postoperative morbidity. A large definitive trial is needed to confirm or refute this and inform widespread clinical practice. METHODS: The Optimisation of Perioperative Cardiovascular Management to Improve Surgical Outcome II (OPTIMISE II) trial is a multicentre, international, parallel group, open, randomised controlled trial. 2502 high-risk patients undergoing major elective gastrointestinal surgery will be randomly allocated in a 1:1 ratio using minimisation to minimally invasive cardiac output monitoring to guide protocolised administration of intravenous fluid combined with low-dose inotrope infusion, or usual care. The trial intervention will be carried out during and for 4 hours after surgery. The primary outcome is postoperative infection of Clavien-Dindo grade II or higher within 30 days of randomisation. Participants and those delivering the intervention will not be blinded to treatment allocation; however, outcome assessors will be blinded when feasible. Participant recruitment started in January 2017 and is scheduled to last 3 years, within 50 hospitals worldwide. ETHICS/DISSEMINATION: The OPTIMISE II trial has been approved by the UK National Research Ethics Service and has been approved by responsible ethics committees in all participating countries. The findings will be disseminated through publication in a widely accessible peer-reviewed scientific journal. TRIAL REGISTRATION NUMBER: ISRCTN39653756.The OPTIMISE II trial is supported by Edwards Lifesciences (Irvine, CA) and the UK National Institute for Health Research through RMP’s NIHR Professorship

Nurses' perceptions of aids and obstacles to the provision of optimal end of life care in ICU

Contains fulltext : 172380.pdf (publisher's version ) (Open Access

Contribution to the study of clay desiccation : simultaneous analysis of strain and stress fields

La terre crue, matériau utilisé dans la construction depuis des millénaires, présente actuellement une alternative intéressante aux matériaux onéreux et énergivores. Dans les conditions climatiques et économiques actuelles, ce matériau connaît un regain d’intérêt tant pour ses caractéristiques écologiques que pour ses propriétés thermo-hygroscopiques très performantes. Néanmoins, le matériau « terre crue » présente une vulnérabilité liée à la fissuration due aux déformations de retrait provoquées par la dessiccation. L’objectif de ce travail de thèse est de contribuer à une meilleure compréhension des mécanismes d’apparition et de propagation des fissures dans les matériaux argileux sous sollicitations hydriques. Dans ce contexte, une étude expérimentale et phénoménologique du retrait libre d’une part, du retrait empêché d’autre part est réalisée, afin de caractériser les déformations de retrait et l’amorce de la fissuration, en relation avec l’état de contrainte interne généré par dessiccation dans les sols argileux. Ceci a nécessité le développement d’un dispositif expérimental prototype adapté à la dessiccation des sols argileux et appelé DIC-CRT (Digital Image Correlation - Clay Ring Test). Il combine trois techniques expérimentales : la corrélation d’images numériques (DIC) l’essai de retrait empêché à l’anneau (CRT) ; la tensiométrie pour le suivi de la succion durant le processus de dessiccation. Différentes conditions aux limites, géométriques (forme et épaisseur des éprouvettes…), mécaniques (rugosité du support, retrait empêché...) et hydriques (hygrométrie ambiante) sont prospectées. Des paramètres pertinents pour quantifier les efforts internes et l'intensité des fissures dans les matériaux sont identifiés. Par ailleurs, l’effet de renforts à base de fibres végétales sur la cinétique de déformations, l’amorce et l’intensité de la fissuration sont prospectés.Raw earth, a material that has been used in construction for thousands of years, currently provides an interesting alternative to expensive and power-consuming materials. The current climatic and economic conditions have led to a renewed interest in this material, both for its ecological characteristics and for its high-performance thermo-hygroscopic properties. Nevertheless, the "raw earth" material presents a vulnerability related to cracking due to shrinkage strains induced by desiccation. The aim of this thesis research is to contribute to a better insight into crack appearance and propagation mechanisms in clayey materials subjected to hydric solicitations. In this context, an experimental and phenomenological study of both free desiccation and retained desiccation is carried out in order to characterize the shrinkage strains and the crack initiation, related to the internal stresses state induced by desiccation in clayey soils. Therefore, a prototype experimental device adapted to the desiccation of clayey soils and called DIC-CRT (Digital Image Correlation - Clay Ring Test), is developed. It combines three experimental techniques: Digital Image Correlation (DIC), Clay Ring Test (CRT); and tensiometry to measure suction during the drying process. Several boundary conditions, geometrical (specimen shape and thickness...), mechanical (support roughness, restrained shrinkage...) and hydric (ambient humidity) are prospected. Relevant parameters to quantify the internal stresses and the cracks intensity in the materials are defined. In addition, the effect of plant-based reinforcements on deformation kinetics, crack initiation and intensity are prospected

Contribution à l'étude de la dessiccation des argiles : analyse simultanée des champs de déformation et de contrainte

Raw earth, a material that has been used in construction for thousands of years, currently provides an interesting alternative to expensive and power-consuming materials. The current climatic and economic conditions have led to a renewed interest in this material, both for its ecological characteristics and for its high-performance thermo-hygroscopic properties. Nevertheless, the "raw earth" material presents a vulnerability related to cracking due to shrinkage strains induced by desiccation. The aim of this thesis research is to contribute to a better insight into crack appearance and propagation mechanisms in clayey materials subjected to hydric solicitations. In this context, an experimental and phenomenological study of both free desiccation and retained desiccation is carried out in order to characterize the shrinkage strains and the crack initiation, related to the internal stresses state induced by desiccation in clayey soils. Therefore, a prototype experimental device adapted to the desiccation of clayey soils and called DIC-CRT (Digital Image Correlation - Clay Ring Test), is developed. It combines three experimental techniques: Digital Image Correlation (DIC), Clay Ring Test (CRT); and tensiometry to measure suction during the drying process. Several boundary conditions, geometrical (specimen shape and thickness...), mechanical (support roughness, restrained shrinkage...) and hydric (ambient humidity) are prospected. Relevant parameters to quantify the internal stresses and the cracks intensity in the materials are defined. In addition, the effect of plant-based reinforcements on deformation kinetics, crack initiation and intensity are prospected.La terre crue, matériau utilisé dans la construction depuis des millénaires, présente actuellement une alternative intéressante aux matériaux onéreux et énergivores. Dans les conditions climatiques et économiques actuelles, ce matériau connaît un regain d’intérêt tant pour ses caractéristiques écologiques que pour ses propriétés thermo-hygroscopiques très performantes. Néanmoins, le matériau « terre crue » présente une vulnérabilité liée à la fissuration due aux déformations de retrait provoquées par la dessiccation. L’objectif de ce travail de thèse est de contribuer à une meilleure compréhension des mécanismes d’apparition et de propagation des fissures dans les matériaux argileux sous sollicitations hydriques. Dans ce contexte, une étude expérimentale et phénoménologique du retrait libre d’une part, du retrait empêché d’autre part est réalisée, afin de caractériser les déformations de retrait et l’amorce de la fissuration, en relation avec l’état de contrainte interne généré par dessiccation dans les sols argileux. Ceci a nécessité le développement d’un dispositif expérimental prototype adapté à la dessiccation des sols argileux et appelé DIC-CRT (Digital Image Correlation - Clay Ring Test). Il combine trois techniques expérimentales : la corrélation d’images numériques (DIC) l’essai de retrait empêché à l’anneau (CRT) ; la tensiométrie pour le suivi de la succion durant le processus de dessiccation. Différentes conditions aux limites, géométriques (forme et épaisseur des éprouvettes…), mécaniques (rugosité du support, retrait empêché...) et hydriques (hygrométrie ambiante) sont prospectées. Des paramètres pertinents pour quantifier les efforts internes et l'intensité des fissures dans les matériaux sont identifiés. Par ailleurs, l’effet de renforts à base de fibres végétales sur la cinétique de déformations, l’amorce et l’intensité de la fissuration sont prospectés