Lattice strain measurements using synchrotron diffraction to calibrate a micromechanical modeling in a ferrite–cementite steel

In situ tensile tests were performed at room temperature on a ferrite–cementite steel specifically designed for this study. The evolution of the average stress in ferrite during loading was analyzed by X-ray diffraction.Lattice strain measurements were performed with synchrotron ring diffraction in both ferrite and cementite.These in situ tests were complemented by macroscopic tensile and reversible tensile-compression tests to study the Bauschinger effect. In order to reproduce stresses in ferrite and cementite particles,a recently developed micromechanical Internal Length Mean Field (ILMF) model based on a generalized self-consistent scheme is applied. In this designed ferrite–cementite steel,the third ‘‘phase’’of the model represents finite intermediate‘‘layers’’in ferrite due to large geometrically necessary dislocation (GND) densities around cementite particles. The assumed constant thickness of the layers is calibrated thanks to the obtained experimental data.The ILMF model is validated by realistic estimates of the Bauschinger stress and the large difference between mean stresses in ferrite and in cementite phases.This difference cannot be reproduced by classic two-phase homogenization schemes without intermediate GND layers

Multi Sensor Data Fusion Architectures for Air Traffic Control Applications

Nowadays, the radar is no longer the sole technology which is able to ensure the surveillance of air traffic. The extensive deployment of satellite systems and air-to-ground data links leads to the emergence of complementary means and techniques on which a great deal of research and experiments have been carried out over the past ten years. In such an environment, the sensor data processing, which is a key element in any Air Traffic Control (ATC) centre, has been continuously upgraded so as to follow the sensor technology evolution and in the meantime improves the quality in term of continuity, integrity and accuracy criteria. This book chapter proposes a comprehensive description of the state of art and the roadmap for the future of the multi sensor data fusion architectures and techniques in use in ATC centres. The first part of the chapter describes the background of ATC centres, while the second part of the chapter points out various data fusion techniques. Multi radar data processing architecture is analysed and a brief definition of internal core tracking algorithms is given as well as a comparative benchmark based on their respective advantages and drawbacks. The third part of the chapter focuses on the most recent evolution that leads from a Multi Radar Tracking System to a Multi Sensor Tracking System. The last part of the chapter deals with the sensor data processing that will be put in operation in the next ten years. The main challenge will be to provide the same level of services in both surface and air surveillance areas in order to offer: ⢠highly accurate air and surface situation awareness to air traffic controllers, ⢠situational awareness via Traffic Information System â Broadcast (TIS-B) services to pilots and vehicle drivers, and ⢠new air and surface safety, capacity and efficiency applications to airports and airlines

Air Traffic Control Tracking Systems Performance Impacts with New Surveillance Technology Sensors

Nowadays, the radar is no longer the only technology able to ensure the surveillance of air traffic. The extensive deployment of satellite systems and air-to-ground data links lead to the emergence of other means and techniques on which a great deal of research and experiments have been carried out over the past ten years. In such an environment, the sensor data processing, which is a key element of an Air Traffic Control center, has been continuously upgraded so as to follow the sensor technology evolution and, at the same time, ensure a more efficient tracking continuity, integrity and accuracy. In this book chapter we propose to measure the impacts of the use of these new technology sensors in the tracking systems currently used for Air Traffic Control applications. The first part of the chapter describes the background of new-technology sensors that are currently used by sensor data processing systems. In addition, a brief definition of internal core tracking algorithms used in sensor data processing components, is given as well as a comparison between their respective advantages and drawbacks. The second part of the chapter focuses on the Multi Sensor Tracking System performance requirements. Investigation regarding the use of Automatic Dependent Surveillance â Broadcast reports and/or with a multi radars configuration, are conducted. The third part deals with the impacts of the âvirtual radarâ or âradar-likeâ approaches that can be used with ADS-B sensors, on the multi sensor tracking system performance. The fourth and last part of the chapter discusses the impacts of sensor data processing performance on sub-sequent safety nets functions that are: ⢠Short term conflict alerts (STCA), ⢠Minimum Safe Altitude Warnings (MSAW), and ⢠Area Proximity Warnings (APW)

Vers une approche à champs moyens à longueurs internes validée par dynamique des champs de dislocations : application aux effets de taille de particules dures dans un matériau de type ferrite / carbures

Une approche à champs moyens à longueurs internes rend compte des effets de taille d’inclusions dures noyées dans une matrice ferritique. Une couche intermédiaire entre l’inclusion et la matrice reflète la présence de GND dues aux gradients de distorsion plastique. L’épaisseur de cette couche et ses effets sur l’écrouissage sont obtenus à l’aide d’une théorie mécanique des champs de dislocations basée sur l’incompatibilité de réseau et l’équation de transport des dislocations de Mura

Prognostic Significance of New Immunohistochemical Markers in Refractory Classical Hodgkin Lymphoma: A Study of 59 Cases

Although most classical Hodgkin lymphoma patients are cured, a significant minority fail after primary therapy and may die as result of their disease. To date, there is no consensus on biological markers that add value to usual parameters (which comprise the International Prognostic Score) used at diagnosis to predict outcome. We evaluated 59 patients (18 with primary refractory or early relapse disease and 41 responders) for bcl2, Ki67, CD20, TiA1 and c-kit expression by semi-quantitative immunohistochemical study and correlated the results with the response to treatment

Early acute microvascular kidney transplant rejection in the absence of anti-HLA antibodies is associated with preformed IgG antibodies against diverse glomerular endothelial cell antigens

International audienceBACKGROUND: Although anti-HLA antibodies (Abs) cause most antibody-mediated rejections of renal allografts, non-anti-HLA Abs have also been postulated to contribute. A better understanding of such Abs in rejection is needed.METHODS: We conducted a nationwide study to identify kidney transplant recipients without anti-HLA donor-specific Abs who experienced acute graft dysfunction within 3 months after transplantation and showed evidence of microvascular injury, called acute microvascular rejection (AMVR). We developed a crossmatch assay to assess serum reactivity to human microvascular endothelial cells, and used a combination of transcriptomic and proteomic approaches to identify non-HLA Abs.RESULTS: We identified a highly selected cohort of 38 patients with early acute AMVR. Biopsy specimens revealed intense microvascular inflammation and the presence of vasculitis (in 60.5%), interstitial hemorrhages (31.6%), or thrombotic microangiopathy (15.8%). Serum samples collected at the time of transplant showed that previously proposed anti-endothelial cell Abs-angiotensin type 1 receptor (AT1R), endothelin-1 type A and natural polyreactive Abs-did not increase significantly among patients with AMVR compared with a control group of stable kidney transplant recipients. However, 26% of the tested AMVR samples were positive for AT1R Abs when a threshold of 10 IU/ml was used. The crossmatch assay identified a common IgG response that was specifically directed against constitutively expressed antigens of microvascular glomerular cells in patients with AMVR. Transcriptomic and proteomic analyses identified new targets of non-HLA Abs, with little redundancy among individuals.CONCLUSIONS: Our findings indicate that preformed IgG Abs targeting non-HLA antigens expressed on glomerular endothelial cells are associated with early AMVR, and that cell-based assays are needed to improve risk assessments before transplant

Complement-activating donor-specific anti-HLA antibodies in solid organ transplantation: systematic review, meta-analysis, and critical appraisal.

peer reviewed[en] INTRODUCTION: Several studies have investigated the impact of circulating complement-activating anti-human leukocyte antigen donor-specific antibodies (anti-HLA DSAs) on organ transplant outcomes. However, a critical appraisal of these studies and a demonstration of the prognostic value of complement-activating status over anti-HLA DSA mean fluorescence intensity (MFI) level are lacking. METHODS: We conducted a systematic review, meta-analysis and critical appraisal evaluating the role of complement-activating anti-HLA DSAs on allograft outcomes in different solid organ transplants. We included studies through Medline, Cochrane, Scopus, and Embase since inception of databases till May 05, 2023. We evaluated allograft loss as the primary outcome, and allograft rejection as the secondary outcome. We used the Newcastle-Ottawa Scale and funnel plots to assess risk of bias and used bias adjustment methods when appropriate. We performed multiple subgroup analyses to account for sources of heterogeneity and studied the added value of complement assays over anti-HLA DSA MFI level. RESULTS: In total, 52 studies were included in the final meta-analysis (11,035 patients). Complement-activating anti-HLA DSAs were associated with an increased risk of allograft loss (HR 2.77; 95% CI 2.33-3.29, p<0.001; I²=46.2%), and allograft rejection (HR 4.98; 95% CI 2.96-8.36, p<0.01; I²=70.9%). These results remained significant after adjustment for potential sources of bias and across multiple subgroup analyses. After adjusting on pan-IgG anti-HLA DSA defined by the MFI levels, complement-activating anti-HLA DSAs were significantly and independently associated with an increased risk of allograft loss. DISCUSSION: We demonstrated in this systematic review, meta-analysis and critical appraisal the significant deleterious impact and the independent prognostic value of circulating complement-activating anti-HLA DSAs on solid organ transplant risk of allograft loss and rejection

Tobramycine et biofilm : une histoire revisitée

International audiencePseudomonas aeruginosa est un pathogène opportuniste de l'Homme, qui en mode de vie biofilm, entraîne des infections de type chronique principalement au niveau des systèmes respiratoire et urinaire. La tobramycine, un antibiotique de la famille des aminoglycosides, provoque en concentration subinhibitrice, une augmentation de la formation du biofilm. L'observation en microscopie confocale à balayage laser de l'effet d'une telle concentration sur P. aeruginosa montre une modification de l'architecture du biofilm, avec notamment une augmentation de la quantité d'ADN extracellulaire dans la matrice. Dans ce contexte l'objectif principal de ce travail est de comprendre les mécanismes moléculaires impliqués dans l'augmentation de biofilm chez P. aeruginosa en réponse à une concentration subinhibitrice de tobramycine. L'analyse globale du protéome par spectrométrie de masse en tandem (LTQ-Orbitrap) de P. aeruginosa cultivée en biofilm montre une dérégulation de la production de 174 protéines appartenant principalement aux classes fonctionnelles (PseudoCAP), « Facteurs sécrétés », « Facteurs impliqués dans la transcription, et le métabolisme des ARNs », et « Métabolismes (énergétique, carboné, acides aminés, nucléotides ». L'expression de différentes cibles, choisies dans chaque classe fonctionnelle, a été évaluée en RT-PCR quantitative, et différents essais phénotypiques pour conforter ces données ont été réalisés. De manière remarquable, en plus d'induire la biosynthèse des pompes à efflux impliquées dans la réponse aux aminoglycosides, les résultats montrent que la tobramycine induit chez P. aeruginosa cultivée en biofilm une augmentation de la production des molécules du quorum sensing (N-acyl-homosérine lactones et 2-alkyl-4-quinolones) et de l'expression de plusieurs petits ARNs non codants. L'ensemble de ces données suggère différents modes d'action moléculaires de la tobramycine qui pourrait contribuer à l'augmentation de la formation de biofilm chez P. aeruginosa

Antibody-mediated rejection in pediatric small bowel transplantation: Capillaritis is a major determinant of C4d positivity in intestinal transplant biopsies

The diagnostic criteria for antibody-mediated rejection (ABMR) after small bowel transplantation (SBT) are not clearly defined, although the presence of donor-specific antibodies (DSAs) has been reported to be deleterious for graft survival. We aimed to determine the incidence and prognostic value of DSAs and C4d in pediatric SBT and to identify the histopathologic features associated with C4d positivity. We studied all intestinal biopsies (IBx) obtained in the first year posttransplantation (N = 345) in a prospective cohort of 23 children. DSAs and their capacity to fix C1q were identified by using Luminex technology. Eighteen patients (78%) had DSAs, and 9 had the capacity to fix C1q. Seventy-eight IBx (22.6%) were C4d positive. The independent determinants of C4d positivity were capillaritis grades 2 and 3 (odds ratio [OR] 4.02, P = .047 and OR 5.17, P = .003, respectively), mucosal erosion/ulceration (OR 2.8, P = .019), lamina propria inflammation grades 1 and 2/3 (OR 1.95, P = .043 and OR 3.1, P = .016, respectively), and chorion edema (OR 2.16, P = .028). Complement-fixing DSAs and repeated C4d-positive IBx were associated with poor outcome (P = .021 and P = .001, respectively). Our results support that capillaritis should be considered as a feature of ABMR in SBT and identify C1q-fixing DSAs and repeated C4d positivity as potential markers of poor outcome