3D Finite Element Simulations of strip lines of a YBCO/Au Fault Current Limiter

Geometrical aspects of the design of fault current limiters (FCL) have a great impact on their performance. Recently, the University of Geneva have presented optimized geometries obtained by splitting the FCL into many small dissipative lengths in order to distribute the power along the device. We have performed 3D finite element method (FEM) simulations for studying the behavior of strip lines of a YBCO/Au FCL in AC nominal use (sinusoidal current at industrial frequency) up to 3 Ic. Particular attention has been paid to the mesh, due to the very large involved aspect ratios. The numerical results show a concentration of the electric field in the sharp corners. This results in very large power dissipation, which has been experimentally confirmed by wafer cracks during over-Ic tests. A new geometry, taking into account the length of the connecting path and the corner optimization, has been proposed. Finally, simulations coupling electromagnetic and thermal equations show the behavior of the device when a default occurs on the electrical network. This work is supported by the Swiss National Science Foundation through the National Center of Competence in Research “Materials with Novel Electronic Properties – MaNEP

Bologna guidelines for diagnosis and management of adhesive small bowel obstruction (ASBO) : 2017 update of the evidence-based guidelines from the world society of emergency surgery ASBO working group

Background: Adhesive small bowel obstruction (ASBO) is a common surgical emergency, causing high morbidity and even some mortality. The adhesions causing such bowel obstructions are typically the footprints of previous abdominal surgical procedures. The present paper presents a revised version of the Bologna guidelines to evidence-based diagnosis and treatment of ASBO. The working group has added paragraphs on prevention of ASBO and special patient groups. Methods: The guideline was written under the auspices of the World Society of Emergency Surgery by the ASBO working group. A systematic literature search was performed prior to the update of the guidelines to identify relevant new papers on epidemiology, diagnosis, and treatment of ASBO. Literature was critically appraised according to an evidence-based guideline development method. Final recommendations were approved by the workgroup, taking into account the level of evidence of the conclusion. Recommendations: Adhesion formation might be reduced by minimally invasive surgical techniques and the use of adhesion barriers. Non-operative treatment is effective in most patients with ASBO. Contraindications for non-operative treatment include peritonitis, strangulation, and ischemia. When the adhesive etiology of obstruction is unsure, or when contraindications for non-operative management might be present, CT is the diagnostic technique of choice. The principles of non-operative treatment are nil per os, naso-gastric, or long-tube decompression, and intravenous supplementation with fluids and electrolytes. When operative treatment is required, a laparoscopic approach may be beneficial for selected cases of simple ASBO. Younger patients have a higher lifetime risk for recurrent ASBO and might therefore benefit from application of adhesion barriers as both primary and secondary prevention. Discussion: This guideline presents recommendations that can be used by surgeons who treat patients with ASBO. Scientific evidence for some aspects of ASBO management is scarce, in particular aspects relating to special patient groups. Results of a randomized trial of laparoscopic versus open surgery for ASBO are awaited.Peer reviewe

Genetic Evidence Implicates the Immune System and Cholesterol Metabolism in the Aetiology of Alzheimer's Disease

Background 1Late Onset Alzheimer's disease (LOAD) is the leading cause of dementia. Recent large genome-wide association studies (GWAS) identified the first strongly supported LOAD susceptibility genes since the discovery of the involvement of APOE in the early 1990s. We have now exploited these GWAS datasets to uncover key LOAD pathophysiological processes. Methodology We applied a recently developed tool for mining GWAS data for biologically meaningful information to a LOAD GWAS dataset. The principal findings were then tested in an independent GWAS dataset. Principal Findings We found a significant overrepresentation of association signals in pathways related to cholesterol metabolism and the immune response in both of the two largest genome-wide association studies for LOAD. Significance Processes related to cholesterol metabolism and the innate immune response have previously been implicated by pathological and epidemiological studies of Alzheimer's disease, but it has been unclear whether those findings reflected primary aetiological events or consequences of the disease process. Our independent evidence from two large studies now demonstrates that these processes are aetiologically relevant, and suggests that they may be suitable targets for novel and existing therapeutic approaches

Analysis of shared heritability in common disorders of the brain

ience, this issue p. eaap8757 Structured Abstract INTRODUCTION Brain disorders may exhibit shared symptoms and substantial epidemiological comorbidity, inciting debate about their etiologic overlap. However, detailed study of phenotypes with different ages of onset, severity, and presentation poses a considerable challenge. Recently developed heritability methods allow us to accurately measure correlation of genome-wide common variant risk between two phenotypes from pools of different individuals and assess how connected they, or at least their genetic risks, are on the genomic level. We used genome-wide association data for 265,218 patients and 784,643 control participants, as well as 17 phenotypes from a total of 1,191,588 individuals, to quantify the degree of overlap for genetic risk factors of 25 common brain disorders. RATIONALE Over the past century, the classification of brain disorders has evolved to reflect the medical and scientific communities' assessments of the presumed root causes of clinical phenomena such as behavioral change, loss of motor function, or alterations of consciousness. Directly observable phenomena (such as the presence of emboli, protein tangles, or unusual electrical activity patterns) generally define and separate neurological disorders from psychiatric disorders. Understanding the genetic underpinnings and categorical distinctions for brain disorders and related phenotypes may inform the search for their biological mechanisms. RESULTS Common variant risk for psychiatric disorders was shown to correlate significantly, especially among attention deficit hyperactivity disorder (ADHD), bipolar disorder, major depressive disorder (MDD), and schizophrenia. By contrast, neurological disorders appear more distinct from one another and from the psychiatric disorders, except for migraine, which was significantly correlated to ADHD, MDD, and Tourette syndrome. We demonstrate that, in the general population, the personality trait neuroticism is significantly correlated with almost every psychiatric disorder and migraine. We also identify significant genetic sharing between disorders and early life cognitive measures (e.g., years of education and college attainment) in the general population, demonstrating positive correlation with several psychiatric disorders (e.g., anorexia nervosa and bipolar disorder) and negative correlation with several neurological phenotypes (e.g., Alzheimer's disease and ischemic stroke), even though the latter are considered to result from specific processes that occur later in life. Extensive simulations were also performed to inform how statistical power, diagnostic misclassification, and phenotypic heterogeneity influence genetic correlations. CONCLUSION The high degree of genetic correlation among many of the psychiatric disorders adds further evidence that their current clinical boundaries do not reflect distinct underlying pathogenic processes, at least on the genetic level. This suggests a deeply interconnected nature for psychiatric disorders, in contrast to neurological disorders, and underscores the need to refine psychiatric diagnostics. Genetically informed analyses may provide important "scaffolding" to support such restructuring of psychiatric nosology, which likely requires incorporating many levels of information. By contrast, we find limited evidence for widespread common genetic risk sharing among neurological disorders or across neurological and psychiatric disorders. We show that both psychiatric and neurological disorders have robust correlations with cognitive and personality measures. Further study is needed to evaluate whether overlapping genetic contributions to psychiatric pathology may influence treatment choices. Ultimately, such developments may pave the way toward reduced heterogeneity and improved diagnosis and treatment of psychiatric disorders

Impact of opioid-free analgesia on pain severity and patient satisfaction after discharge from surgery: multispecialty, prospective cohort study in 25 countries

Background: Balancing opioid stewardship and the need for adequate analgesia following discharge after surgery is challenging. This study aimed to compare the outcomes for patients discharged with opioid versus opioid-free analgesia after common surgical procedures.Methods: This international, multicentre, prospective cohort study collected data from patients undergoing common acute and elective general surgical, urological, gynaecological, and orthopaedic procedures. The primary outcomes were patient-reported time in severe pain measured on a numerical analogue scale from 0 to 100% and patient-reported satisfaction with pain relief during the first week following discharge. Data were collected by in-hospital chart review and patient telephone interview 1 week after discharge.Results: The study recruited 4273 patients from 144 centres in 25 countries; 1311 patients (30.7%) were prescribed opioid analgesia at discharge. Patients reported being in severe pain for 10 (i.q.r. 1-30)% of the first week after discharge and rated satisfaction with analgesia as 90 (i.q.r. 80-100) of 100. After adjustment for confounders, opioid analgesia on discharge was independently associated with increased pain severity (risk ratio 1.52, 95% c.i. 1.31 to 1.76; P < 0.001) and re-presentation to healthcare providers owing to side-effects of medication (OR 2.38, 95% c.i. 1.36 to 4.17; P = 0.004), but not with satisfaction with analgesia (beta coefficient 0.92, 95% c.i. -1.52 to 3.36; P = 0.468) compared with opioid-free analgesia. Although opioid prescribing varied greatly between high-income and low- and middle-income countries, patient-reported outcomes did not.Conclusion: Opioid analgesia prescription on surgical discharge is associated with a higher risk of re-presentation owing to side-effects of medication and increased patient-reported pain, but not with changes in patient-reported satisfaction. Opioid-free discharge analgesia should be adopted routinely

Correction: genetic evidence implicates the immune system and cholesterol metabolism in the aetiology of Alzheimer's disease.

[This corrects the article on p. e13950 in vol. 5.]. Background: Late Onset Alzheimer's disease (LOAD) is the leading cause of dementia. Recent large genome-wide association studies (GWAS) identified the first strongly supported LOAD susceptibility genes since the discovery of the involvement of APOE in the early 1990s. We have now exploited these GWAS datasets to uncover key LOAD pathophysiological processes. Methodology: We applied a recently developed tool for mining GWAS data for biologically meaningful information to a LOAD GWAS dataset. The principal findings were then tested in an independent GWAS dataset. Principal Findings: We found a significant overrepresentation of association signals in pathways related to cholesterol metabolism and the immune response in both of the two largest genome-wide association studies for LOAD. Significance: Processes related to cholesterol metabolism and the innate immune response have previously been implicated by pathological and epidemiological studies of Alzheimer's disease, but it has been unclear whether those findings reflected primary aetiological events or consequences of the disease process. Our independent evidence from two large studies now demonstrates that these processes are aetiologically relevant, and suggests that they may be suitable targets for novel and existing therapeutic approaches

Modélisation de matériaux supraconducteurs : application à un limiteur de courant

This thesis is focused on the modelling of superconducting materials, and in particular, hightemperature superconducting materials. This work is divided in two parts: first, the dynamic magnetic field mapping obtained by measurements is used in order to reconstruct the dynamic current distribution inside a tape assuming a model describing its global behavior. In the second part, superconductors in over-critical regime have been both electrically and thermally modelized with a finite element method. Calculations have been applied on a current limiter and compared to a constructed and measured device at the University of Geneva. The first chapter is an introduction to high-temperature superconducting materials, where the main superconducting physical properties used are presented. Next, we introduce the different existing models which can be used for describing the behavior of a superconducting tape. With the help of the Bean model, a novel method to evaluate the current distribution in a mono-filamentary superconducting tape from surface magnetic field measurements is proposed. The obtained results are compared with more precise, but more complex, methods like finite element modeling, which will be used for the second part of this work. The last part is focused on the modelization of superconducting material in overcritical regime. To achieve this goal, we need to introduce a different expression than the usual Ec(J/Jc)^n power-law for describing the electric behavior of the material in a much wider current range covering over-critical excursion. The original proposition we made is able to fit the measurements made on YBCO tapes, allowing to describe the transition from the superconducting to the normal state. Then, to taking into account the thermal phenomena, the temperature dependence of the electrical parameters has been introduced in order to solve a coupled electromagnetic and thermal problem: solving a time step of the electromagnetic part leads to the knowledge of the local losses. These losses are injected inside the thermal part. The resulting temperature computation is used to modify the electrical parameters for the next time step. Finally, this method has been applied in order to simulate a superconducting current limiter. The global behavior of the device can be reproduced by the implemented numerical model, which also allows the study of the local variables, like current density distribution or temperature profile. The obtained results can be used to optimize a device according to specific criteria. In particular, we have proposed geometric modifications for avoiding possible local thermal runaway, which can lead to the destruction of the device. This proposition has beeing inspired the new design, which is now tested.L'objectif principal de cette thèse est la modélisation de matériaux supraconducteurs, et plus particulièrement, de ceux dits à haute température critique. Ce travail est divisé en deux parties distinctes : dans un premier temps, nous nous intéressons à la reconstruction de la distribution dynamique du courant dans la section d'un ruban supraconducteur à l'aide d'un modèle décrivant son comportement global. Ensuite, nous nous focalisons sur la modélisation électromagnétique et thermique par éléments finis des supraconducteurs en régime sur-critique, c'est à dire au-delà du courant critique Ic. Une introduction à la supraconductivité est faite dans le premier chapitre de ce travail, présentant les propriétés physiques principales que possède un matériau supraconducteur. Ensuite, nous décrirons les différents modèles existants permettant de décrire le comportement d'un échantillon supraconducteur. En se basant sur le modèle de Bean, nous proposons une nouvelle méthode permettant d'évaluer la distribution du courant dans la section d'un ruban monofilamentaire à partir de la mesure du profil magnétique à sa surface. Les résultats obtenus sont comparés avec ceux données par une modélisation certes plus précise, mais aussi plus complexe : l'utilisation de la méthode des éléments finis. Cette dernière sera largement utilisée dans la seconde partie de ce travail, qui traite de la modélisation de matériaux en régime sur-critique. Ceci nécessite d'introduire une formulation différente de l'habituelle loi de puissance Ec(J/Jc)^n pour décrire le comportement électrique du matériau dans une plage de courant plus importante, incluant les régimes sur-critiques. Pour cela, nous proposons une méthode originale, permettant d'approcher des mesures effectuées sur des échantillons d'YBCO et autorisant la description de la transition de l'état supraconducteur vers l'état normal. La dépendance en température a aussi été introduite afin d'étudier les phénomènes thermiques qui se produisent. Il est ainsi possible de résoudre de manière couplée les équations électromagnétiques et thermiques du problème : la résolution d'un pas de temps électromagnétique conduit à la connaissance des pertes locale. Ces pertes sont injectées dans le modèle thermique, et permet de calculer l'augmentation de température correspondante. Ce résultat est alors utilisé pour modifier les paramètres électriques en vue de la résolution du prochain pas de temps. Finalement, cette méthode a été utilisée afin de simuler le comportement d'un limiteur de courant supraconducteur. Le comportement global du système peut être reproduit par le modèle numérique implémenté, autorisant ainsi l'étude des variables locales, telles que la densité de courant ou le profil de température. Les résultats obtenus peuvent être utilisés afin d'optimiser les performances du dispositif selon des critères spécifiques. C'est ainsi que nous avons proposé une modification de la géométrie permettant d'éviter un possible emballement thermique qui pourrait conduire à la destruction du système. Sur la base de cette proposition, des modifications ont été apportées au design du dispositif, et sont actuellement testées

Observations ichtyologiques effectuées en 1979

During 1979, some «rare» fishes were observed in la Rochelle, Fouras, Arcachon and Lorient, and along the coasts of Charente-Maritime, especially Chlamydoselachus anguineus, Pseudotriakis microdon, Somniosus microcephalus, Raniceps raninus, Zenopsis conchifer, Xiphias glaclius, Pholis gurmellus, Centrolophus niger and Solea senegalensis.En 1979, nous avons noté un certain nombre d'observations ichtyologiques, recueillies soit dans les pêches débarquées dans les ports de la Rochelle, Fouras, Arcachon et Lorient, soit à la côte en échouage ou en pêche à pied. Parmi, nous avons remarqué plus particulièrement les espèces suivantes : Chlamycloselachus anguineus, Pseudotriakis microdon, Somniosus microcephalus, Raniceps raninus, Zenopsis conchifer, Xiphias gladius, Pholis gunnellus, Centrolophus niger et Solea senegalensis

Computer Modeling of YBCO Fault Current Limiter Strips Lines in Over-Critical Regime With Temperature Dependent Parameters

We present the results of an advanced numerical model for fault current limiter (FCL) based on HTS thin films in which both thermal and electromagnetic aspects are taken into account. This model allows simulating the behavior of FCL in the over-critical current regime and we used it for studying strip lines of a YBCO/Au FCL on sapphire substrate. The electromagnetic and thermal equations have been implemented in finite-element method (FEM) software in order to obtain a model for investigating the comportment of the superconductor when the current exceeds $I_{c}$ . In particular, materials equations have been implemented in order to simulate the electrical behavior of superconducting devices with strong over-critical currents. We report results of simulations in voltage source mode where currents largely exceed $I_{c}$ . The global behavior of the FCL is compared with measurements, showing a good agreement. The use of FEM simulations offers the advantage to give access to local variables such as current density or temperature. Studies with this model can replace expensive experiments where very high current density might damage or destroy the FCL device