Relations entre la microstructure 3D et les propriétés mécaniques dans des réfractaires électrofondus à très haute teneur en zircone

National audienceLe THTZ (réfractaire électrofondu à Très Haute Teneur en Zircone) est un matériau utilisé pour la construction de fours verriers. Il est composé d'un squelette dendritique de zircone imprégné de phase vitreuse. L'objectif de l'étude est d'étudier l'influence de la composition sur les propriétés des phases, la topologie microstructurale et les propriétés mécaniques du THTZ. Les microstructures 3D ont été investiguées par tomographie X à l'ESRF (synchrotron de Grenoble). Les clichés obtenus ont donné lieu à des analyses d'images permettant de caractériser la topologie microstructurale des différents matériaux. Une relation entre la vitesse d'attaque par l'acide fluorhydrique (HF) et la densité de surface a été identifiée. Parallèlement, des calculs par éléments finis tridimensionnels, réalisées à partir de volumes élémentaires représentatifs de la microstructure réelle, ont permis d'estimer l'influence de la morphologie sur les propriétés mécaniques macroscopiques

Frozen section analysis and sentinel lymph node biopsy in well differentiated thyroid cancer

BACKGROUND: The aim of this study is to prospectively review the role of sentinel lymph node (SLN) biopsy in the management of well differentiated thyroid carcinoma (WDTC), and to determine the efficacy of intraoperative frozen section analysis at detecting SLN metastasis and central compartment involvement. METHODS: The SLN biopsy protocol using 1% methylene blue was performed in 300 patients undergoing thyroidectomy for WDTC. A limited pretracheal central compartment neck dissection (CCND) was performed on all patients. Lymph nodes staining blue were considered as SLN’s. Both frozen and permanent section analyses were performed. RESULTS: SLN’s with metastasis were found in 14.3% (43/300) of cases. Of this, 11% (33/300) were positive on intraoperative frozen section analysis. Frozen section results failed in predicting central compartment involvement in 15 cases (5%) whereas central neck compartment involvement was missed in 5 cases (1.7%) when based on permanent section results. On frozen section analysis, the sensitivity, specificity, positive predictive value and negative predictive value (95% CI) of our SLN biopsy technique aiming to remove all disease from the central compartment was 68.8% (53.6-80.9), 100% (98.1-100), 100% (87.0-100) and 94.4% (90.7-96.7) respectively with P < 0.0001. On permanent section analysis, the values were 89.6% (76.6-96.1), 100% (98.1-100), 100% (89.8-100), and 98.1% (95.3-99.3) with P < 0.0001. CONCLUSION: This data series demonstrates that patients with WDTC have positive SLN’s in 14.3% of cases. Moreover, when the SLN’s are negative for metastasis on frozen section, the central compartment was disease-free in 94.4% of cases. Finally, this study shows that 23.3% of positive SLN’s were false negatives on intraoperative frozen section. According to this data, SLN involvement is an accurate predictor of central compartment metastasis, however surgeons should use caution when relying on intraoperative frozen section to determine whether to perform a CCND

Combined transcriptomic-(1)H NMR metabonomic study reveals yhat monoethylhexyl phthalate stimulates adipogenesis and glyceroneogenesis in human adipocytes

Adipose tissue is a major storage site for lipophilic environmental contaminants. The environmental metabolic disruptor hypothesis postulates that some pollutants can promote obesity or metabolic disorders by activating nuclear receptors involved in the control of energetic homeostasis. In this context, monoethylhexyl phthalate (MEHP) is of particular concern since it was shown to activate the peroxisome proliferator-activated receptor γ (PPARγ) in 3T3-L1 murine preadipocytes. In the present work, we used an untargeted, combined transcriptomic-(1)H NMR-based metabonomic approach to describe the overall effect of MEHP on primary cultures of human subcutaneous adipocytes differentiated in vitro. MEHP stimulated rapidly and selectively the expression of genes involved in glyceroneogenesis, enhanced the expression of the cytosolic phosphoenolpyruvate carboxykinase, and reduced fatty acid release. These results demonstrate that MEHP increased glyceroneogenesis and fatty acid reesterification in human adipocytes. A longer treatment with MEHP induced the expression of genes involved in triglycerides uptake, synthesis, and storage; decreased intracellular lactate, glutamine, and other amino acids; increased aspartate and NAD, and resulted in a global increase in triglycerides. Altogether, these results indicate that MEHP promoted the differentiation of human preadipocytes to adipocytes. These mechanisms might contribute to the suspected obesogenic effect of MEHP

Clinical and Histopathological Features of Thyroid Cancer with TERT Promoter Molecular Alterations in Isolation Versus with Concurrent Molecular Alterations: A Multicenter Retrospective Study

Background/Objectives Molecular testing of thyroid nodules enables the detection of genetic alterations, which can help assess the risk of malignancy and tumor behavior. While telomerase reverse transcriptase (TERTp) mutations are known to be associated with aggressive disease, their exact prognostic significance when occurring alone or with other molecular alterations remains underreported. Methods This study examined patients with thyroid cancer treated at two tertiary care hospitals from 2017 to 2024. We compared tumor behavior in patients with TERTp molecular alterations occurring alone and with concurrent molecular alterations. Aggressive histologic subtypes were defined as tall-cell, hobnail, and columnar variants of papillary carcinoma, as well as poorly differentiated and anaplastic carcinoma. High-risk disease was defined according to the 2015 ATA guidelines as gross extrathyroidal extension, lymph node metastasis >3 cm, postoperative elevated serum thyroglobulin, distant metastases, and/or positive resection margins. Statistical analysis was performed to assess differences between groups. Results 30 patients with TERTp-positive thyroid malignancies were included. TERTp/BRAF V600E was the most prevalent mutation combination (n = 13, 43.3%), followed by TERTp alone (n = 8, 26.7%) and TERTp/RAS (n = 7, 23.4%). TERTp/EIF1AX/GNAS and TERTp/EIF1AX/PIK3CA were the least common combinations (n = 1, 3.3% each). Nodules with TERTp and concurrent mutations were significantly more likely to be classified as high-risk (p = 0.006) and were more frequently associated with aggressive histologic subtypes (p = 0.003) compared to those with TERTp mutations alone, which tended to exhibit more benign behavior. Conclusions Thyroid carcinomas harboring both TERTp and concurrent molecular alterations are associated with more aggressive features and a higher likelihood of being classified as high-risk. In contrast, TERTp mutations occurring alone do not confer an elevated risk

Carbon balance components of a black locust-based agroforestry site under Mediterranean climate

Agroforestry systems (AFS) can provide many services, among which sequestering atmospheric carbon (C) dioxide (CO2) into both tree biomass and soil organic matter for mitigating climate warming. Such high performances were documented in several studies, but data are still scarse for covering the broad range of agrosystems – climate combinations. More particularly, data of the different C stocks and fluxes among the different components of the AFS needs to be documented for robust estimates of C sink strength. This study aims at providing values of C stocks and fluxes of a black locust (Robinia pseudoacacia L.)-based agroforestry site in Mauguio, Southern France. The different compartments of the AFS were investigated: the black locust rows, the herbaceous strip planted of various grassland species along the trees and the intercropping, constituted by a rotation cereals/legumes. The crop rotations comprised durum wheat, barley, chickpea and pea, but we presented the data for the barley planting year in 2021. A forest plantation and a pure crop planting systems were also studied as control modalities. The three planting systems were repeated in three independent blocks. Aboveground tree biomass growth was estimated for the agroforestry and the forestry plots from allometric models. Black locust litter fall was quantified also in the agroforestry and forestry plots. For each planting systems, root biomasses, root C contents and root growth were estimated . Aboveground herbaceous biomasses and C contents were also measured in 1m2 squared plots at different seasons. Soil microbial biomass and soil CO2 efflux were measured in all components and planting systems. All data currently under processing will be normalized per area unit. The effect of the planting system was assessed in order to determine the added value of the agroforestry system with respect to the pure planting systems

Opening Computational Neuroscience to a Wider Audience: Virtual Escape Room for Kids

As researchers it is vital that we increase the accessibility, transparency, diversity, and inclusivity of our work. One-way Neuromatch has championed this is by having outreach sessions for children (8+) to explain computational-neuroscience concepts. For the 2022 Neuromatch conference we designed an online escape room with the two goals 1) to show who is a neuroscience researcher and what they do and 2) to explain a research topic. To show who/what is a researcher, the escape room began with a video describing the day-to-day life of a researcher. The subsequent videos discussed how mathematics and neuroscience are combined to model decision-making. We framed the videos around the question “Will I walk or bike to school?” to describe the concepts of the drift-diffusion equation and how its application. At the end of each video there was a multiple-choice question, a correct response gave clues to the next image and a letter for the keyword needed to complete the escape room. The escape room was translated into six languages: Arabic, Chinese, French, English, Hebrew and Spanish. The materials have been made open access and can be easily adapted to create content to communicate other scientific research questions to a broad audience

Carglumic acid: an additional therapy in the treatment of organic acidurias with hyperammonemia?

<p>Abstract</p> <p>Background</p> <p>Hyperammonemia in patients with methylmalonic aciduria (MMA) and propionic aciduria (PA) is caused by accumulation of propionyl-CoA which decreases the synthesis of N-acetyl-glutamate, the natural activator of carbamyl phosphate synthetase 1. A treatment approach with carglumic acid, the structural analogue of N-acetyl-glutamate, has been proposed to decrease high ammonia levels encountered in MMA and PA crises.</p> <p>Case presentation</p> <p>We described two patients (one with MMA and one with PA) with hyperammonemia at diagnosis. Carglumic acid, when associated with standard treatment of organic acidurias, may be helpful in normalizing the ammonia level.</p> <p>Conclusion</p> <p>Even though the usual treatment which decreases toxic metabolites remains the standard, carglumic acid could be helpful in lowering plasma ammonia levels over 400 micromol/L more rapidly.</p