Estudios de corrosión sobre estructuras de Titanio poroso obtenidas mediante diferentes técnicas de fabricación

Se realizarán estudios comparativos de potential libre y curvas potenciodinamicas sobre estructuras porosas de Titanio fabricadas mediante la técnica de sinterización (space Holder) y mediante técnicas de manufactura aditiva (3D tinta) También se evaluará el efecto de introducir una capa bioactiva de titanato de sodio sobre estructuras porosasIncomin

Corrosion studies on porous titanium structures obtained through different manufacturing techniques

Through the years, the medicine has been modernized to reach today a complex science complying diagnosis, treatments and prevention of illness. This project is focused on the orthopedic surgery and more particularly on medical implants. Medical implants are medical devices which are incorporated in the human body in order to support or replace a missing biological structure. The human body is fragile, and it is necessary to pay attention to the biocompatibility of the medical implants in order to avoid contamination or poisoning. This is why medical implants are mostly made, nowadays, in biocompatible materials such as ceramics, polymers or specific metal alloys as titanium alloys or Nickel alloys. These materials present good corrosion resistance or even are completely inert towards the human body. This project will be focused on titanium orthopedic implants. Titanium and its alloys present interesting properties as a high strength to density ratio, a good corrosion resistance due to the combination of the different surface-formed oxide layers and offer an excellent biocompatibility. This unique combination of properties makes them ideal materials for medical implants. However, titanium implants present issues regarding long-term performances due to a mismatch in mechanical properties between the implant and natural bone. These differences can enhance stress shielding effect. To avoid this mismatch, the solution is to adjust the mechanical properties of titanium so that they are as similar as possible to those of bone. This is achieved by the introduction of a sufficient amount of porosity. Indeed, by controlling the porosity, it is possible to tailor the mechanical properties of a solid material. In order to confer a superior bone-bonding property to titanium implants, attempts have been made to coat their surfaces with a thin layer of bone-bonding ceramic, such assodium titanate, by the means of chemical and heat treatments To avoid infection, caused by the introduction of a foreign body in human body, silver ions, known for their antibacterial activity, may be incorporated to the medical implant. Beside silver ions, Gallium ions also present good antibacterial activity but they're mostly known for their impact on bone resorption. The aim of this study is to produce comparative studies of corrosion resistance with different samples of titanium implants. Will be studied the impact of the heat treatment and the introduction of the antibacterial ions on the electrochemical behavior.Incomin

Le Chemin de l’Univers.

Le « Chemin de l’Univers » est une exposition permanente composée de 27 panneaux / posters qui présenteront différents objets observés et/ou détectés dans l’Univers. Ces objets seront décrits successivement, selon leur distance croissante par rapport à la Terre. Les panneaux seront installés sur la commune de La Couyère (Ille-et-Vilaine, France)

Endocarditis Due to Neisseria bacilliformis in a Patient with a Bicuspid Aortic Valve ▿

We report a case of endocarditis due to the rod-shaped Neisseria species Neisseria bacilliformis. The phenotypic characterization of this recently characterized bacteria is difficult, and the identification requires the sequencing of the 16S rRNA gene. The resolution of the disease was complete after appropriate antibiotic therapy, and surgery was not required

Towards Human in the Loop Analysis of Complex Point Clouds: Advanced Visualizations, Quantifications, and Communication Features in Virtual Reality

International audienceMultiple fields in biological and medical research produce large amounts of point cloud data with high dimensionality and complexity. In addition, a large set of experiments generate point clouds, including segmented medical data or single-molecule localization microscopy. In the latter, individual molecules are observed within their natural cellular environment. Analyzing this type of experimental data is a complex task and presents unique challenges, where providing extra physical dimensions for visualization and analysis could be beneficial. Furthermore, whether highly noisy data comes from single-molecule recordings or segmented medical data, the necessity to guide analysis with user intervention creates both an ergonomic challenge to facilitate this interaction and a computational challenge to provide fluid interactions as information is being processed. Several applications, including our software DIVA for image stack and our platform Genuage for point clouds, have leveraged Virtual Reality (VR) to visualize and interact with data in 3D. While the visualization aspects can be made compatible with different types of data, quantifications, on the other hand, are far from being standard. In addition, complex analysis can require significant computational resources, making the real-time VR experience uncomfortable. Moreover, visualization software is mainly designed to represent a set of data points but lacks flexibility in manipulating and analyzing the data. This paper introduces new libraries to enhance the interaction and human-in-theloop analysis of point cloud data in virtual reality and integrate them into the open-source platform Genuage. We first detail a new toolbox of communication tools that enhance user experience and improve flexibility. Then, we introduce a mapping toolbox allowing the representation of physical properties in space overlaid on a 3D mesh while maintaining a point cloud dedicated shader. We introduce later a new and programmable video capture tool in VR and desktop modes for intuitive data dissemination. Finally, we highlight the protocols that allow simultaneous analysis and fluid manipulation of data with a high refres

Risques climatiques et développement durable

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New Approach to Accelerated Image Annotation by Leveraging Virtual Reality and Cloud Computing

International audienceThree-dimensional imaging is at the core of medical imaging and is becoming a standard in biological research. As a result, there is an increasing need to visualize, analyze and interact with data in a natural three-dimensional context. By combining stereoscopy and motion tracking, commercial virtual reality (VR) headsets provide a solution to this critical visualization challenge by allowing users to view volumetric image stacks in a highly intuitive fashion. While optimizing the visualization and interaction process in VR remains an active topic, one of the most pressing issue is how to utilize VR for annotation and analysis of data. Annotating data is often a required step for training machine learning algorithms. For example, enhancing the ability to annotate complex three-dimensional data in biological research as newly acquired data may come in limited quantities. Similarly, medical data annotation is often time-consuming and requires expert knowledge to identify structures of interest correctly. Moreover, simultaneous data analysis and visualization in VR is computationally demanding. Here, we introduce a new procedure to visualize, interact, annotate and analyze data by combining VR with cloud computing. VR is leveraged to provide natural interactions with volumetric representations of experimental imaging data. In parallel, cloud computing performs costly computations to accelerate the data annotation with minimal input required from the user. We demonstrate multiple proof-of-concept applications of our approach on volumetric fluorescent microscopy images of mouse neurons and tumor or organ annotations in medical images

Breast carcinomas with osteoclast-like giant cells: a comprehensive clinico-pathological and molecular portrait and evidence of RANK-L expression

International audienceBreast carcinomas (BC) with osteoclast-like giant cells (OGC) are rare. Despite their distinct stromal features, their molecular characteristics remain unknown. Here, we report comprehensive clinico-pathological and molecular findings for 27 patients diagnosed with BC-OGC at Institut Curie between 2000 and 2021. Seventeen (63%) cases were invasive carcinomas of no special type (IC NST) with OGC (OGC-IC NST), four (15%) were mixed or multifocal cases with and without OGC (OGC-Mixed), and six (22%) were metaplastic carcinomas with OGC (OGC-MC). All OGC-IC NST and OGC-Mixed cases were ER+ HER2− tumors (most being luminal A based on transcriptomic subtyping, when available), while all OGC-MC were triple-negative. The median age at diagnosis was 46, 45 and 62 years for OGC-IC NST, OGC-Mixed and OGC-MC, respectively. Three patients developed distant metastases (one OGC-IC NST, two OGC-Mixed), one of whom died of metastatic disease (OGC-Mixed), and one other patient died of locally advanced disease (OGC-MC). Histopathological evaluation comparing 13 OGC-IC NST and 19 control IC NST without OGC confirmed that OGC-IC NST showed significantly higher density of vessels (by CD34 immunohistochemistry (IHC)), iron deposits (Perls stain), and CD68 and CD163-positive cell infiltrates. Genomic findings for nine OGC-IC NST and four OGC-MC were consistent with the underlying histologic subtype, including activating alterations of the PI3K/AKT/mTOR pathway in 7/13 cases. Using RNA-seq data, differential gene expression analysis between OGC-IC NST (n = 7) and control IC NST without OGC (n = 7) revealed significant overexpression of TNFSF11 (RANK-L), TNFRSF11A (RANK), CSF1 (M-CSF), CSF1R, and genes encoding osteoclastic enzymes (MMP9, ACP5, CTSK, CTSB) in OGC-IC NST, while OPG (osteoprotegerin) was underexpressed. We also confirmed for the first time RANK-L expression in BC with OGC by IHC (seen in 15 out of 16 cases, and only in 2 of 16 controls without OGC). These findings could offer a rationale for further investigating RANK-L as a therapeutic target in BC with OGC

Microsatellite instability detection in breast cancer using drop-off droplet digital PCR

International audienceThe use of conventional methods (immunohistochemistry, pentaplex PCR) for detecting microsatellite instability (MSI), a predictive biomarker of immunotherapy efficacy, is debated for cancers with low MSI prevalence, such as breast cancer (BC). We developed two multiplex drop-off droplet digital PCR (ddPCR) assays targeting four microsatellites, initially identified from public BC whole-genome sequencing dataset. Performances of the assays were investigated and 352 tumor DNA and 28 circulating cell-free DNA from BC patients, with unknown MSI status were blindly screened. Cross-validation of ddPCR MSI status with other MSI detection methods was performed. We then monitored circulating tumor DNA (ctDNA) dynamics before and during pembrolizumab immunotherapy in one patient with MSI-high (MSI-H) metastatic BC. The assays showed high analytical specificity and sensitivity (limit of detection = 0.16%). Among N = 380 samples, seven (1.8%) were found as MSI-H by ddPCR with six of them confirmed by next-generation sequencing (NGS). Specificity was 100% in N = 133 microsatellite stable BC submitted to NGS. In the patient with MSI-H metastatic BC, ctDNA monitoring revealed an early decrease of microsatellite mutant allelic frequencies during immunotherapy. These results demonstrated MSI detection by ddPCR, a non-invasive, fast and cost-effective approach, allowing for large pre-screening of BC patients who may benefit from immunotherapy

PLK1 inhibition exhibits strong anti-tumoral activity in CCND1-driven breast cancer metastases with acquired palbociclib resistance

International audienceA significant proportion of patients with oestrogen receptor (ER) positive breast cancers (BC) develop resistance to endocrine treatments (ET) and relapse with metastatic disease. Here we perform whole exome sequencing and gene expression analysis of matched primary breast tumours and bone metastasis-derived patient-derived xenografts (PDX). Tran-scriptomic analyses reveal enrichment of the G2/M checkpoint and up-regulation of Polo-like kinase 1 (PLK1) in PDX. PLK1 inhibition results in tumour shrinkage in highly proliferating CCND1-driven PDX, including different RB-positive PDX with acquired palbociclib resistance. Mechanistic studies in endocrine resistant cell lines, suggest an ER-independent function of PLK1 in regulating cell proliferation. Finally, in two independent clinical cohorts of ER positive BC, we find a strong association between high expression of PLK1 and a shorter metastases-free survival and poor response to anastrozole. In conclusion, our findings support clinical development of PLK1 inhibitors in patients with advanced CCND1-driven BC, including patients progressing on palbociclib treatment