Improvement to Defect Detection by Ultrasonic Data Processing: The DTVG Method

In the case of coarse grained austenitic stainless steel, an important diminution in the defect detection possibilities is noted. The wave amplitude is attenuated and can also be deviated, according to the importance of anisotropy and/or heterogeneity

Development of a New Method for the Inspection of a 3D Volume of Ultrasonic Data

NDT technologies by ultrasounds are in constant progress. The advance is considerable for sensors and acquisition systems. The means for data processing follow this evolution. In order to meet the demand for processing very high volumes of data, we propose in this paper a method of volume automatic thresholding. The application concerns the testing of austenitic steel or else, for the nuclear industry. The thresholding techniques from the image histogram are inadequate as the ultrasonic image histogram is unimodal. The study of the image with the cooccurrence matrix which is a two dimensionnal histogram allows to clearly show the noise-defect transition. Several authors have elaborated on thresholding techniques of an image from the cooccurrence matrix. These vary according to the type of exploited image [1–2]. We showed the good results of thresholding by cooccurrence matrix on images with a defect. We develop in this paper a two-part study. Firstly, after a brief account of the matrix exploitation, we show the limits of this method in bearing simulated images. We then describe the chosen approach to extend the method to the volume thresholding problem. We give results from a data volume obtained on austenitic steel testing

Modelling of ultrasound transmission through a solid-liquid interface comprising a network of gas pockets

International audienceUltrasonic inspection of sodium-cooled fast reactor requires a good acoustic coupling between the transducer and the liquid sodium. Ultrasonic transmission through a solid surface in contact with liquid sodium can be complex due to the presence of microscopic gas pockets entrapped by the surface roughness. Experiments are run using substrates with controlled roughness consisting of a network of holes and a modeling approach is then developed. In this model, a gas pocket stiffness at a partially solid-liquid interface is defined. This stiffness is then used to calculate the transmission coefficient of ultrasound at the entire interface. The gas pocket stiffness has a static, as well as an inertial component, which depends on the ultrasonic frequency and the radiative mass

Optimal co-occurrence matrix for automatic segmentation of ultrasonic images

This paper introduces a new method of segmentation using automatic thresholding adapted to the NDT ultrasonic images . This study is based on image analysis through co-occurrence matrixes . It shows an optimization of the r and 0 parameters of the co-occurrence matrix enabling to define more acurately the border between noise and defect echoes . The segmentation is obtained by automatically taking into account a threshold derived from a determination curve calculated front the co-occurrence matrix . This curve, called Average Product of Variances Measure, is an analysis of the distribution of the matrix coefficients . The results show behaviors of the co-occurrence matrixes and of the threshold selection curves that justify perfectly the analysis performed on the characteristics of the image .Cet article présente une nouvelle méthode de segmentation par seuillage automatique, adaptée aux images obtenues en contrôle non destructif par ultrasons. Cette étude est fondée sur l'analyse d'image par matrice de co-occurrence. On présente une optimisation des paramètres r et Θ de la matrice de co-occurrence permettant de mieux définir la frontière qui sépare le bruit des échos de défauts. La segmentation s'obtient par la prise en compte automatique d'un seuil issu d'une courbe de détermination calculée à partir de la matrice de co-occurrenc

Safe lipid nanocapsule-based gel technology to target lymph nodes and combat mediastinal metastases from an orthotopic non-small-cell lung cancer model in SCID-CB17 mice

The purpose of this study is the assessment of gel technology based on a lauroyl derivative of gemcitabine encapsulated in lipid nanocapsules delivered subcutaneously or intravenously after dilution to target lymph nodes, induce less systemic toxicity and combat mediastinal metastases from an orthotopic model of human, squamous, non-small-cell lung cancer Ma44-3 cells implanted in severe combined immunodeficiency mice. The gel technology mainly targeted lymph nodes as revealed by the biodistribution study. Moreover, the gel technology induced no significant myelosuppression (platelet count) in comparison with the control saline group, unlike the conventional intravenous gemcitabine hydrochloride treated group (P < 0.05). Besides, the gel technology, delivered subcutaneously twice a week, was able to combat locally mediastinal metastases from the orthotopic lung tumor and to significantly delay death (P < 0.05) as was the diluted gel technology delivered intravenously three times a week

Protection from ultraviolet damage and photocarcinogenesis by vitamin d compounds

© Springer Nature Switzerland AG 2020. Exposure of skin cells to UV radiation results in DNA damage, which if inadequately repaired, may cause mutations. UV-induced DNA damage and reactive oxygen and nitrogen species also cause local and systemic suppression of the adaptive immune system. Together, these changes underpin the development of skin tumours. The hormone derived from vitamin D, calcitriol (1,25-dihydroxyvitamin D3) and other related compounds, working via the vitamin D receptor and at least in part through endoplasmic reticulum protein 57 (ERp57), reduce cyclobutane pyrimidine dimers and oxidative DNA damage in keratinocytes and other skin cell types after UV. Calcitriol and related compounds enhance DNA repair in keratinocytes, in part through decreased reactive oxygen species, increased p53 expression and/or activation, increased repair proteins and increased energy availability in the cell when calcitriol is present after UV exposure. There is mitochondrial damage in keratinocytes after UV. In the presence of calcitriol, but not vehicle, glycolysis is increased after UV, along with increased energy-conserving autophagy and changes consistent with enhanced mitophagy. Reduced DNA damage and reduced ROS/RNS should help reduce UV-induced immune suppression. Reduced UV immune suppression is observed after topical treatment with calcitriol and related compounds in hairless mice. These protective effects of calcitriol and related compounds presumably contribute to the observed reduction in skin tumour formation in mice after chronic exposure to UV followed by topical post-irradiation treatment with calcitriol and some, though not all, related compounds

Novel Gemcitabine Conjugated Albumin Nanoparticles: a Potential Strategy to Enhance Drug Efficacy in Pancreatic Cancer Treatment

Purpose: The present study reports a novel conjugate of gemcitabine (GEM) with bovine serum albumin (BSA) and thereof nanoparticles (GEM-BSA NPs) to potentiate the therapeutic efficacy by altering physicochemical properties, improving cellular uptake and stability of GEM. Methods: The synthesized GEM-BSA conjugate was extensively characterized by NMR, FTIR, MALDI-TOF and elemental analysis. Conjugation mediated changes in structural conformation and physicochemical properties were analysed by fluorescence, Raman and CD spectroscopy, DSC and contact angle analysis. Further, BSA nanoparticles were developed from BSA-GEM conjugate and extensively evaluated against in-vitro pancreatic cancer cell lines to explore cellular uptake pathways and therapeutic efficacy. Results: Various characterization techniques confirmed covalent conjugation of GEM with BSA. GEM-BSA conjugate was then transformed into NPs via high pressure homogenization technique with particle size 147.2 ± 7.3, PDI 0.16 ± 0.06 and ZP -19.2 ± 1.4. The morphological analysis by SEM and AFM revealed the formation of smooth surface spherical nanoparticles. Cellular uptake studies in MIA PaCa-2 (GEM sensitive) and PANC-1 (GEM resistant) pancreatic cell lines confirmed energy dependent clathrin internalization/endocytosis as a primary mechanism of NPs uptake. In-vitro cytotoxicity studies confirmed the hNTs independent transport of GEM in MIA PaCa-2 and PANC-1 cells. Moreover, DNA damage and annexin-V assay revealed significantly higher apoptosis level in case of cells treated with GEM-BSA NPs as compared to free GEM. Conclusions: GEM-BSA NPs were found to potentiate the therapeutic efficacy by altering physicochemical properties, improving cellular uptake and stability of GEM and thus demonstrated promising therapeutic potential over free drug

Energy Conscious Building Design for the Humid Subtropical Climate of Southern China

The present research concerns automatic control of the mechanical quality of a weld on a circumferential component. A method of image processing is developed that searches for the limits of the weld melted zone for each angular position, so as to extract the evolution in terms of the main geometric characteristics of the zone (penetration depth, etc...). It is an image segmentation operation since it achieves the extraction of useful elements for interpretation