Journal articles: 'Mécanique du contact – Localisation'

1

Scheibert, Julien, Georges Debrégeas, and Alexis Prevost. "Mécanique du contact rugueux et perception tactile." Reflets de la physique, no. 16 (October 2009): 17–19. http://dx.doi.org/10.1051/refdp/2009018.

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Alart, Par P. "Méthode de Newton généralisée en mécanique du contact." Journal de Mathématiques Pures et Appliquées 76, no. 1 (January 1997): 83–108. http://dx.doi.org/10.1016/s0021-7824(97)89946-1.

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Olive, F., A. Waintal, J. L. Buévoz, and J. C. Reynaud. "Mesure de profils sans contact mécanique par interférométrie acoustique." Journal de Physique III 2, no. 10 (October 1992): 1957–66. http://dx.doi.org/10.1051/jp3:1992217.

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Frossard, Etienne. "La mécanique dissipative des géo-matériaux granulaires et ses applications pratiques en Génie Civil." Revue Française de Géotechnique, no. 167 (2021): 2. http://dx.doi.org/10.1051/geotech/2021007.

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L’article, résultant d’un travail de long terme sur la physique des géo-matériaux granulaires et la pratique du génie civil de grandes infrastructures, synthétise une vision nouvelle du comportement mécanique de ces matériaux, à partir d’approches dissipatives micromécaniques originales. Après le contexte et les hypothèses-clé, il présente les aspects essentiels des structures dissipatives induites par la friction de contact élémentaire, associée à des spécificités de mécanique statistique dans ces matériaux en mouvement quasi-statique, et leur expression multi-échelle par des relations tensorielles fortes : les équations de la dissipation d’énergie résultant de la friction. Sur cette base, est ensuite établi un large ensemble de propriétés pratiques d’usage général en génie civil, incluant : le critère de rupture, le couplage résistance au cisaillement/variations de volume, la compaction cyclique, l’équilibre géostatique « au repos »… Bien que l’essentiel de l’article soit focalisé sur les caractères induits par la friction de contact, une dernière section présente d’autres propriétés-clé induites par la rupture des granulats, autre processus dissipatif après la friction de contact. Ces propriétés incluent des incidences explicites sur les effets d’échelle dans le comportement structural d’ouvrages, vérifiées sur de grands ouvrages.

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Brocato, Maurizio, Alain Ehrlacher, and Philippe Tamagny. "Description eulerienne de la mécanique d'un front de discontinuité avec apparition d'une localisation de la déformation." Comptes Rendus de l'Académie des Sciences - Series IIB - Mechanics-Physics-Astronomy 326, no. 11 (November 1998): 693–98. http://dx.doi.org/10.1016/s1251-8069(98)80001-8.

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Gourlay, Christopher M., Somboon Otarawanna, B. Meylan, and Arne K. Dahle. "Reynolds’ Dilatancy and Shear Bands in Semi-Solid Alloys." Solid State Phenomena 141-143 (July 2008): 337–42. http://dx.doi.org/10.4028/www.scientific.net/ssp.141-143.337.

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This paper studies the conditions under which strain localisation occurs in partially solid alloys and compares localisation in rheology experiments with features in the industrial processes of Thixomolding® and high pressure die casting (HPDC). To study the fundamentals of localisation, vane rheometry, modified to measure volumetric changes, is used to shear magnesium alloy AZ91 during solidification. Deformation is found to readily localise when the initial microstructure consists of an assembly of crystals in contact. It is shown that such microstructures expand as they are sheared due to Reynolds’ dilatancy, and that localisation takes the form of dilatant shear bands. A study of microstructural features in industrial castings demonstrates that similar dilatant shear bands can form during Thixomoulding® and HPDC.

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Lowell, J. "Constraints on contact charging of insulators. I. Spatial localisation of insulator states." Journal of Physics D: Applied Physics 19, no. 1 (January 14, 1986): 95–104. http://dx.doi.org/10.1088/0022-3727/19/1/014.

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Pomeau, Yves. "Représentation de la ligne de contact mobile dans les équations de la mécanique des fluides." Comptes Rendus de l'Académie des Sciences - Series IIB - Mechanics 328, no. 5 (May 2000): 411–16. http://dx.doi.org/10.1016/s1620-7742(00)00043-x.

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Cherpi, M., A. Delage, T. Paul, and M. Renard. "Nociception in the Skin: nociceptors are no longer the only actors." Douleur et Analgésie 32, no. 4 (December 2019): 217–20. http://dx.doi.org/10.3166/dea-2020-0081.

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Les nocicepteurs à terminaisons libres ont longtemps été considérés comme les seuls senseurs nociceptifs dans la peau. Abdo et al. réévaluent le rôle des cellules de Schwann (CSs), cellules gliales de soutien du système nerveux périphérique, dans la perception de la douleur chez la souris. Après observation de la morphologie et de la localisation des CSs et des fibres nociceptives dans la peau, les chercheurs s’intéressent à leur relation fonctionnelle. Ils génèrent des souris exprimant des canaux ioniques photosensibles à la surface des CSs. Cela leur permet de les stimuler spécifiquement (par optogénétique) tout en mesurant la réponse électrique du nerf palmaire. En combinant l’excitation ou l’inhibition des CSs avec des tests comportementaux, ils mesurent la capacité des CSs à sensibiliser les souris à la douleur thermique et mécanique. Enfin, des CSs sont isolées pour évaluer leur capacité à répondre à un stimulus mécanique. Les observations par microscopie électronique et à fluorescence révèlent que les nocicepteurs se trouvent entourés par le cytoplasme des CSs dans le derme et accolés à ces dernières dans l’épiderme. Ce complexe glioneural se ramifie au niveau subépidermal. Les chercheurs décident ainsi d’appeler ces cellules gliales « cellules de Schwann nociceptives » (CSn). Leur stimulation par optogénétique révèle une augmentation de l’activité électrique des fibres nociceptives, des comportements « de douleur » chez la souris, et augmente la sensibilité des souris aux stimuli douloureux mécaniques et thermiques. L’inhibition via optogénétique des CSn diminue leur sensibilité aux stimuli mécaniques mais ne modifie pas leur sensibilité aux stimuli thermiques. L’enregistrement unicellulaire des CSn révèle qu’elles sont hautement sensibles aux stimuli mécaniques. Les auteurs de cette étude ont découvert un nouveau type de cellule de Schwann nociceptive jouant un rôle important dans la genèse et modulation de la nociception cutanée.

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Gerges, Tony, Philippe Lombard, Bruno Allard, and Michel Cabrera. "Attirer l’étudiant vers l’électronique à l’aide de la plastronique 3D et de la fabrication additive." J3eA 21 (2022): 2047. http://dx.doi.org/10.1051/j3ea/20222047.

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L’enseignement de l’électronique se heurte à un manque d’appétence de la part des étudiants. Ouvrir le champ technologique vers la fabrication additive et la plastronique est de nature à solliciter de nouveau l’intérêt des étu-diants. Malheureusement il est délicat de donner un premier exemple pertinent qui confirme l’intérêt et mette les diffé-rents cours en perspective, car la plastronique balaie des connaissances allant des matériaux, à la chimie, la plasturgie, la conception mécanique 3D, etc. L’article présente un mini-projet sur la réalisation d’un dispositif plastronique à l’aide de la fabrication additive et de la métallisation autocatalytique, comme premier contact des étudiants avec les aspects tech-nologiques. Il s’agit de fabriquer une maquette de camion imprimée en 3D, qui embarque sur sa surface non plane un circuit électronique typique. Tout d’abord le schéma électronique et la conception mécanique sont réalisés et assemblés. L’objet est ensuite imprimé et les pistes sont métallisées. La maquette du camion est obtenue après le brasage des com-posants. Cette maquette vise à provoquer un questionnement de la part de l’étudiant et lui permettre de mieux position-ner le contenu des cours et travaux pratiques d’une formation spécialisée en plastronique.

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Yang, Jingyuan, Huayu Duan, Linxiao Li, Edward Stewart, Junhui Huang, and Roger Dixon. "1D CNN Based Detection and Localisation of Defective Droppers in Railway Catenary." Applied Sciences 13, no. 11 (June 4, 2023): 6819. http://dx.doi.org/10.3390/app13116819.

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Defective droppers pose a significant threat to the performance of the contact between the train pantograph and railway catenary. In this paper, the impact of damaged droppers on the performance of pantograph–catenary interaction behaviour is analysed, and the impact of varying degrees of damage to each dropper is labelled. To improve the classification accuracy when both the damage degree and position are considered, a model integrating multiple 1D CNNs is proposed. Approaches including randomly searching the optimal hyper-parameters and K-fold cross-validation are used to prevent overfitting and to ensure model performance regardless of the training data subset selected. Compared with a conventional 1D CNN, the classification performance of the integrated method is demonstrated using the metrics accuracy, F1-score, precision and recall. It is concluded that, through the use of the integrated 1D CNN, damaged droppers can be detected and localised based on the pantograph–catenary contact force. Hence, intelligent catenary inspection can be enhanced.

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Andreades, Christos, Gian Piero Malfense Fierro, and Michele Meo. "A nonlinear ultrasonic modulation approach for the detection and localisation of contact defects." Mechanical Systems and Signal Processing 162 (January 2022): 108088. http://dx.doi.org/10.1016/j.ymssp.2021.108088.

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Geoffroy, B., F. Bialota, J. P. Bossy, M. Ravallec, F. D'Amico, and Dominique Cuisance. "Les chimiorécepteurs de l'aile chez Glossina pallidipes (Diptera : Glossinidae) et Stomoxys nigra (Diptera : Muscidae)." Revue d’élevage et de médecine vétérinaire des pays tropicaux 49, no. 2 (February 1, 1996): 141–48. http://dx.doi.org/10.19182/remvt.9532.

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Une étude comparative des organes sensoriels de l'aile, plus particulièrement les chimiorécepteurs, de deux vecteurs de trypanosomoses, Glossina pallidipes Austen, 1903 (transmission cyclique) et Stomoxys nigra Macquart, 1850 (transmission mécanique) a été menée. Leur morphologie, leur localisation et leur rôle sont analysés en fonction du sexe et des variations inter-spécifiques. Une comparaison est faite avec d'autres espèces de glossines et avec Musca domestica. Globalement et par section respective, G. pallidipes possède plus de chimiorécepteurs (mâle : 138,26; femelle : 135,33) que S. nigra (mâle : 89,85; femelle : 95,68) mais moins que G. m. morsitans (mâle : 173,17; femelle : 168), G. m. submorsitans (mâle : 169,29; femelle : 169,52) ou G. austeni (mâle : 160,58; femelle : 156,47). Les écarts d'effectifs des chimiorécepteurs entre mâles et femelles chez une même espèce ne sont pas significatifs. Chez S. nigra, la section E est mieux fournie en chimiorécepteurs chez les deux sexes et les sections A et F en sont dépourvues. En outre, la répartition des soies le long de la nervure costale se limite aux sections B, C, D et E, tandis qu'elle s'observe sur toute la longueur de l'aile chez les glossines. Le rôle possible des chimiorécepteurs est abordé.

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Le Gall, Michel, Charles Dubernard, and Camille Philip-Alliez. "L’imagerie numérique : outil de la gestion thérapeutique des dents incluses." Revue d'Orthopédie Dento-Faciale 55, no. 1 (February 2021): 105–47. http://dx.doi.org/10.1051/odf/2021008.

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Le traitement avec dégagement chirurgical et mise en place orthodontique de canines incluses étant complexe, la décision thérapeutique finale doit s’appuyer sur une concertation pluridisciplinaire impliquant l’orthodontiste et le praticien responsable de l’acte chirurgical. Pour améliorer le pronostic et réduire les échecs et ré-interventions, une appréciation initiale précise de la localisation de la dent, de la présence de résorption initiale, de la direction de traction et de l’ancrage nécessaire, est indispensable. Lorsque l’imagerie conventionnelle ne fournit pas toutes les informations souhaitées, une analyse tridimensionnelle peut être recommandée afin de mieux localiser une dent incluse et mieux visualiser les structures associées. La sensibilité diagnostique de la radiologie conventionnelle étant peu élevée pour la détection de résorptions des dents adjacentes, le scanner augmente celle-ci de 50% en moyenne. Le cone beam peut être proposéafin d’améliorer la prise en charge du patient en se substituant au scanner plus irradiant. L’imagerie médicale en reconstruction 3D est non seulement une aide pour l’orthodontiste de façon à visualiser et mettre en place la mécanique la plus adaptée compte tenu du contexte mais sert aussi au praticien qui va réaliser l’acte de façon à optimiser sa procédure de dégagement (respect des structures environnantes) pour le bien du patient.

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Cheng, Zhuang, Jianfeng Wang, and Wei Li. "Exploring the micromechanical behaviour of sand-rubber mixtures using X-ray micro-tomography." EPJ Web of Conferences 249 (2021): 11009. http://dx.doi.org/10.1051/epjconf/202124911009.

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The micromechanical behaviour of sand-rubber mixtures (SRMs) under monotonic triaxial shear were investigated using X-ray micro-tomography. The localisation of sand particle rotations that occurred in a pure sand sample under shear was inhibited in the sand mixed with 30% rubber grains by mass. Meanwhile, the SRMs exhibited an evolution of sand-sand contact coordination number that is not negatively correlated with sample porosity, dramatically different from that was observed in pure sands. Substantially increasing anisotropy degree of sand-rubber contacts compared with minor changes of sandsand contact fabric was observed, implying the increasingly important role of sand-rubber contacts in the transmission of deviatoric loads as the shear of SRMs progressed.

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Marettová, E., and M. Maretta. "Localisation of S100 Protein and Acetylated Tubulin in Sheep Pancreas." Folia Veterinaria 65, no. 2 (June 1, 2021): 9–16. http://dx.doi.org/10.2478/fv-2021-0012.

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Abstract The pancreas plays a critical role in the control of nutritional homeostasis. It consists of two major parts, the exocrine pancreas, and the endocrine pancreas. In the present study S100 protein and acetylated α-tubulin were used to identify positive structures in both the exocrine and endocrine part of the ovine pancreas. In the exocrine part of the pancreas, a positive reaction to S100 protein was confined to centroacinar cells, intercalated, and intralobular ducts cells. In addition, the S100 protein was localized in the Schwann cells of nerve fibres. On the pancreatic islets, the S100 protein has been observed in Schwann cells of nerve axons, where they form a fine envelope that invests the islet surface. Inside the pancreatic islets, the Schwann cells positive for S100 protein envelope the endocrine cells of the islets. The difference in positivity of the S100 protein was found in relation to the endocrine cells. The relationship between endocrine cell positivity and positive exocrine duct cells was discussed. Acetylated α-tubulin (AT) was restricted to axons of the nerve fibres and was located within the connective tissue accompanying intralobular and inter-lobular ducts, and between secretory acini in close contact with secretory cells.

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Fleming, T. P., D. R. Garrod, and A. J. Elsmore. "Desmosome biogenesis in the mouse preimplantation embryo." Development 112, no. 2 (June 1, 1991): 527–39. http://dx.doi.org/10.1242/dev.112.2.527.

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The molecular processes underlying the formation of the first desmosomes in the mouse early embryo have been examined by immunocytochemical and biochemical techniques using antibody probes recognising desmosomal proteins 1 and 2 (dp1 + 2, desmoplakins), dp3 (plakoglobin), desmosomal glycoprotein 1 (dg1, desmoglein) and dg2 + 3 (desmocollins). Immunofluorescence labelling of staged intact embryos and synchronised cell clusters indicates that dp1 + 2, dg1 and dg2 + 3 are first detectable on the lateral membrane contact sites between trophectoderm cells in early cavitating blastocysts, coincident with the onset of desmosome formation as seen in ultrastructural preparations. Membrane localisation of these antigens is predominantly punctate in appearance, occurs after division to the 32-cell stage and appears to be coincident with blastocoele formation since non-cavitated embryos/cell clusters of equivalent age/cell cycle are usually unlabelled. In contrast, dp3 is first detectable at the 32-cell stage at all internal membrane contact sites (including those with inner cell mass cells) in a continuous linear pattern, and appears in both cavitated and non-cavitated specimens. Subsequently during blastocyst expansion, dp3 localisation becomes punctate and restricted to trophectodermal membranes. Immunoprecipitation of desmosomal antigens following metabolic labelling indicates that synthesis of dp3 is underway from at least compaction in the 8-cell embryo, while dp1 + 2 synthesis is first evident in 16-cell morulae. Synthesis of dg1 and dg2 + 3 is not detectable until the early blastocyst stage. These results suggest that desmosome biogenesis in the preimplantation embryo might be regulated by transcription or translation of desmosomal glycoproteins and by maturational changes in the trophectoderm layer associated with blastocoele formation. The earlier expression and wider distribution of dp3 at cell contact areas may reflect non-desmosomal sites (eg, adherens junctions) for this protein and a possible role for dp3 in the development of intercellular junctions.

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Kolářová, Iva, and Andrea Valigurová. "Hide-and-Seek: A Game Played between Parasitic Protists and Their Hosts." Microorganisms 9, no. 12 (November 25, 2021): 2434. http://dx.doi.org/10.3390/microorganisms9122434.

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After invading the host organism, a battle occurs between the parasitic protists and the host’s immune system, the result of which determines not only whether and how well the host survives and recovers, but also the fate of the parasite itself. The exact weaponry of this battle depends, among others, on the parasite localisation. While some parasitic protists do not invade the host cell at all (extracellular parasites), others have developed successful intracellular lifestyles (intracellular parasites) or attack only the surface of the host cell (epicellular parasites). Epicellular and intracellular protist parasites have developed various mechanisms to hijack host cell functions to escape cellular defences and immune responses, and, finally, to gain access to host nutrients. They use various evasion tactics to secure the tight contact with the host cell and the direct nutrient supply. This review focuses on the adaptations and evasion strategies of parasitic protists on the example of two very successful parasites of medical significance, Cryptosporidium and Leishmania, while discussing different localisation (epicellular vs. intracellular) with respect to the host cell.

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Seno and Aliabadi. "Impact Localisation in Composite Plates of Different Stiffness Impactors under Simulated Environmental and Operational Conditions." Sensors 19, no. 17 (August 22, 2019): 3659. http://dx.doi.org/10.3390/s19173659.

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A parametric investigation of the effect of impactor stiffness as well as environmental and operational conditions on impact contact behaviour and the subsequently generated lamb waves in composite structures is presented. It is shown that differing impactor stiffness generates the most significant changes in contact area and lamb wave characteristics (waveform, frequency, and amplitude). A novel impact localisation method was developed based on the above observations that allows for variations due to differences in impactor stiffness based on modifications of the reference database method and the Akaike Information Criterion (AIC) time of arrival (ToA) picker. The proposed method was compared against a benchmark method based on artificial neural networks (ANNS) and the normalised smoothed envelope threshold (NSET) ToA extraction method. The results indicate that the proposed method had comparable accuracy to the benchmark method for hard impacts under various environmental and operational conditions when trained only using a single hard impact case. However, when tested with soft impacts, the benchmark method had very low accuracy, whilst the proposed method was able to maintain its accuracy at an acceptable level. Thus, the proposed method is capable of detecting the location of impacts of varying stiffness under various environmental and operational conditions using data from only a single impact case, which brings it closer to the application of data driven impact detection systems in real life structures.

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Papavassiliou, Athanasios G. "Localisation of DNA-protein contact points by DMS resistance of complexes resolved in gel retardation assays." Nucleic Acids Research 21, no. 3 (1993): 757–58. http://dx.doi.org/10.1093/nar/21.3.757.

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Owusu, Edward, Asuamah Adade-Yeboah, Kweku Rockson, Solomon Ali Dansieh, and Samuel Kyei Adoma. "Language Use in the Multilingual Classroom Settings of West Africa: A Review of Selected Literature." World Journal of English Language 12, no. 1 (March 24, 2022): 399. http://dx.doi.org/10.5430/wjel.v12n1p399.

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Linguistically, most Africans are multilingual entities. Extremely, the seventeen (17) West African states display this feature. Thus, in a typical L2 classroom in Africa, the learner is likely to come into contact with several languages. These languages are mostly the official languages(s), the second or third language(s), the international language, and the indigenous languages spoken by both the learners and the teachers. Sometimes, the official language(s) is/are selected indigenous languages (for example, Igbo, Yoruba, and Hausa, in the case of Nigeria). In some cases, the second language is the international language used for official engagements and international discourse. In Western Africa, Ghana is one such country that uses English as both the official and international language. When learners from diverse sociocultural backgrounds are exposed to several languages in a particular classroom setting, a lot of processes emerge. One of such processes is nativisation or indigenisation or localisation of the formal classroom language. This is the process where language learners use the formal classroom language in a manner that suits their communicative needs. This paper is a review of selected empirical studies on the use of language in the multilingual classrooms of selected African countries. The cases and papers were purposively sampled from five West African states of Cameroon, Ghana, Guinea-Bissau, Niger, and Nigeria. This paper argues that language contact processes such as localisation, pidginization, and creolization are not aberrant forms per se; and since they serve the informal linguistic needs of multilingual second language learners, they should be given a place in language use.

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Kallaev, T. N., and N. O. Kallaev. "Biomechanical substantiation of compression osteosynthesis in near- and intra-articular fractures." N.N. Priorov Journal of Traumatology and Orthopedics 9, no. 1 (February 2, 2022): 44–48. http://dx.doi.org/10.17816/vto97106.

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Dynamic compressive osteosynthesis using elaborated special device was performed in 182 patients with peri- and intraarticular fractures of various localisation. The biomechanical background of that osteosynthesis was presented on the models of intraarticular fractures. Dosed compression osteosynthesis provides gentle compression on the fragmets taking into account biological resorption in the site of fragments contact till the time of fracture healing. Fixation stability allows to combine the immobilization and rehabilitation periods that decreases the terms of motion restoration in joint, the risk of contracture formation and development of deforming arthrosis. Good and satisfactory anatomical and functional results were achieved in 96.2% of patients

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Chen, Long, Yat Sze Choy, Tian Gang Wang, and Yan Kei Chiang. "Fault detection of wheel in wheel/rail system using kurtosis beamforming method." Structural Health Monitoring 19, no. 2 (June 14, 2019): 495–509. http://dx.doi.org/10.1177/1475921719855444.

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Fault detection systems are typically applied in the railway industry to examine the structural health status of the wheel/rail system. We herein propose a time-domain kurtosis beamforming technique using an array of microphones for the fault identification and localisation of the wheel/rail system under an environment with high background noise. As an acoustics-based noncontact diagnosis method, this technique overcomes the challenge of the contact between the sensors and examined structures, and it is more applicable for impulsive signals of broadband nature, such as impact noise generated from faults on the wheel surface. Moreover, the application of kurtosis enables the identification and localisation at low signal-to-noise ratio. Under such circumstance, the impulsive signals generated by faults were totally merged in rolling noise and background noise. Meanwhile, different types of faults on the wheels could be identified and localised by observing the kurtosis value on the beamforming sound map. The effectiveness of the proposed method to diagnose the type of wheel fault with low signal-to-noise ratio and moving source has been validated experimentally. This method may provide a useful tool for the routine maintenance of trains.

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Clayton, Lesley, Siân V. Stinchcombe, and Martin H. Johnson. "Cell surface localisation and stability of uvomorulin during early mouse development." Zygote 1, no. 4 (November 1993): 333–44. http://dx.doi.org/10.1017/s0967199400001660.

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We have examined immunocytochemically the subcellular distribution of the cell adhesion molecule uvomorulin in cleavage stage mouse embryos using conventional and confocal microscopy, under a range of detergent extraction and fixation regimes. Only traces of uvomorulin were detectable on the surface of unfertilised oocytes, whereas between 6 and 11 h after activation detergent-resistant surface expression was evident. This shift correlates with previously demonstrated changes in the pattern of synthesis and accumulation of uvomorulin from precursor state in unfertilised oocytes to mature protein after fertilisation. Embryos at subsequent stages up to the 8-cell stage exhibited a uniform distribution of uvomorulin on free surfaces and its concentration in regions of contact between blastomeres. At the 8-cell stage, during compaction, there was increased intercellular adhesion with concomitant accumulation of uvomorulin at intercellular contacts, whilst free surface uvomorulin was reduced and became relatively more susceptible to detergent extraction. When compact 8-cell embryos were decompacted in calcium-free medium, uvomorulin at contacts decreased while free surface and cytoplasmic staining increased. Blastomeres disaggregated from 4- and 8-cell embryos showed traces or ‘footprints’ of anti-uvomorulin staining in regions previously in apposition. These footprints disappeared over 45–60 min, during which time uvomorulin distribution became uniform. Possible mechanisms underlying the rearrangements which take place both at fertilisation and during compaction and experimental decompaction are discussed.

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Petitprez, Matthieu, and Katia Mocellin. "Numerical Study of a Crimped Assembly Mechanical Strength." Key Engineering Materials 554-557 (June 2013): 1037–44. http://dx.doi.org/10.4028/www.scientific.net/kem.554-557.1037.

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Electrical contact crimping is a mechanical fastening process commonly used in aeronautical and aero spatial applications. In order to ensure the perfect electrical conduction and acceptable mechanical properties, the assembly have to fullfil some drastic holding force criteria. This outfit is directly dependent on the indentation depth at the end of crimping. The feedback generally reveals that an over crimping will lead to the cable breakage whereas an under crimping will be characterized by the cable sliding into the contact during pulling. The optimal behavior is a combinaison of both phenomena : the cable must become thinner before slipping into the contact. Numerical simulation is an efficient tool to limit the tedious experimental tests. It is the main topic of our work. This paper deals with prediction of the failure type and the force level required to tear out a contact crimped on multistrand cable for different indentation depths. The determination of optimal crimping condition is determined. In order to simulate the contact tensile test, crimping simulation has to be performed. The first step is then to be able to simulate accurately the crimping stage by using appropriate behavior laws and realistic conditions. One difficulty is linked to the small size of our objects. The first one is a 19 strands cable, in which each strand is about 0.15 mm diameter. The second sample is a 1 mm diameter cylindrical copper contact measuring 7 mm long. Adapted testing devices are described. Geometries and mechanical fields are obtained and then exported in the mechanical holding model to ensure realistic prediction [1]. Impact of crimping conditions on the pulling results is discussed. Pulling simulation results are compared to experimental values. The prediction of breakage mechanisms is also studied. Keywords: Crimping process, mechanical fastening operation, finite element computations, mechanical strength, breakout force, tensile test. [1] Fayolle, S., 2008, Etude de la modélisation de la pose et de la tenue mécanique des assemblages par déformation plastique : application au rivetage auto poinçonneur, Thèse de l'Ecole des Mines de Paris.

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Gospodinova, Klimentina D., Adriana D. Angelova, Malena Y. Gergovska, and Daniela T. Grozeva. "Allergic Contact Dermatitis to Acrylates: A Study Among Manicurists and Clients." Journal of Biomedical and Clinical Research 16, no. 2 (November 1, 2023): 186–93. http://dx.doi.org/10.2478/jbcr-2023-0025.

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Summary The study aimеd to investigate the association between the professional environment and hypersensitivity reactions to various contact allergens, features of the clinical course, and types of allergic contact dermatitis (ACD) in 34 manicurists and ten service users. The analysis was based on the data on length of professional experience, localisation of rashes, clinical diagnoses and allergens, and the cause of positive reactions in epicutaneous testing. Pathological skin changes most often affected the upper limbs (hands, palms, fingers). As a diagnosis, the frequency of ACD was the highest – 79.4%, followed by that of dyshidrotic eczema (DE) – 17.6%, which also determines the highest percentage of dermatitis on the upper limbs (97%). Of the patients, 47.1% had a history of the disease for up to one year. For manicurists, the results of patch tests with the specialised MH-1000 series showed the highest frequency of positive reactions to 2-Hydroxyethyl methacrylate (2-HEMA) and 2-Hydroxypropyl methacrylate (2-HPMA) – 88.88% each, Ethylene glycol dimethacrylate (EGDMA) – 83.33% and 2-Hydroxyethyl acrylate (2-HEA) – 61.11%. After combining data for manicurists and clients, correlation analysis found a significant effect on the development of ACD to 2-HPMA (p=0.003) and EGDMA (p=0.005), as well as for hand dermatitis to 2-HEMA (p=0.05) and 2-HEA (p=0.044).

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Poon, C. E., M. Day, and C. R. Murphy. "305. OPPOSING ROLES FOR MUCINS 13 AND 15 IN EARLY PREGNANCY." Reproduction, Fertility and Development 22, no. 9 (2010): 105. http://dx.doi.org/10.1071/srb10abs305.

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Successful pregnancy is dependent on the cumulation of numerous changes in both the uterine luminal epithelium (ULE) and the invading blastocyst prior to implantation. The apical surface of the ULE constitutes the first point of contact with the blastocyst; thus forming an important player in the implantation event. A constituent of this surface comprises the Mucin family of proteins, which is suggested to play an important role in implantation. Prior studies have found that some Mucins form an anti-adhesive surface on the uterine epithelium to prevent implantation of the blastocyst. The formation of this anti-adhesive surface relates to their large extracellular domains which act to ‘mask’ adhesive receptors present on the ULE from interaction with corresponding ligands present on the blastocyst surface. This process of contact inhibition has been termed ‘steric hindrance’. This study examined the localisation of previously uncharacterised Mucins 13 and 15 in the uterus and blastocyst during early pregnancy to investigate their role in the implantation event. Western blotting, cell fractionation and immunofluorescence techniques were utilised in this study. It was found that Mucin 13 localised to the apical cell surface of the ULE at time of implantation while conversely Mucin 15 was lost from the apical cell surface. In the blastocyst, both proteins were localised to the trophoblast cells and the inner cell mass, with Mucin 15 additionally present in the zona pellucida. Further, the changes in localisation of these proteins in the ULE corresponded to changes in their glycosylation profiles from pre-implantation to time of implantation. These results demonstrate that Mucins 13 and 15 participate in contrasting roles in implantation. Mucin 13 may promote adhesion between the uterus and blastocyst to facilitate implantation while Mucin 15 may prevent adhesion through the mechanism of steric hindrance, given its absence from the apical cell surface at time of implantation.

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Avery, James, Brett Packham, Hwan Koo, Ben Hanson, and David Holder. "Self-Abrading Servo Electrode Helmet for Electrical Impedance Tomography." Sensors 20, no. 24 (December 9, 2020): 7058. http://dx.doi.org/10.3390/s20247058.

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Electrical Impedance Tomography (EIT) is a medical imaging technique which has the potential to reduce time to treatment in acute stroke by rapidly differentiating between ischaemic and haemorrhagic stroke. The potential of these methods has been demonstrated in simulation and phantoms, it has not yet successfully translated to clinical studies, due to high sensitivity to errors in scalp electrode mislocation and poor electrode-skin contact. To overcome these limitations, a novel electrode helmet was designed, bearing 32 independently controlled self-abrading electrodes. The contact impedance was reduced through rotation on an abrasive electrode on the scalp using a combined impedance, rotation and position feedback loop. Potentiometers within each unit measure the electrode tip displacement within 0.1 mm from the rigid helmet body. Characterisation experiments on a large-scale test rig demonstrated that approximately 20 kPa applied pressure and 5 rotations was necessary to achieve the target 5 kΩ contact impedance at 20 Hz. This performance was then replicated in a simplified self-contained unit where spring loaded electrodes are rotated by servo motors. Finally, a 32-channel helmet and controller which sequentially minimised contact impedance and simultaneously located each electrode was built which reduced the electrode application and localisation time to less than five minutes. The results demonstrated the potential of this approach to rapidly apply electrodes in an acute setting, removing a significant barrier for imaging acute stroke with EIT.

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HAMLAT, Smail. "Apport de la mécanique du contact pneu-chaussée dans la prédiction de l'évolution de la texture de surface d'un revêtement routier." Revue Européenne de Génie Civil 10, no. 8 (September 2006): 1010. http://dx.doi.org/10.1080/17747120.2006.9692890.

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Alart, Pierre. "Critères d’injectivité et de surjectivité pour certaines applications de $\mathbb {R}^n$ dans lui-même ; application à la mécanique du contact." ESAIM: Mathematical Modelling and Numerical Analysis 27, no. 2 (1993): 203–22. http://dx.doi.org/10.1051/m2an/1993270202031.

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L. Wong, R. N. Deo, S. Rathnayaka, B. Shannon, C. S. Zhang, J. Kodikara, W. K. Chiu, and H. Widyastuti. "Leak Detection and Quantification of Leak Size along Water Pipe using Optical Fibre Sensors Package." Electronic Journal of Structural Engineering 18, no. 1 (January 1, 2018): 47–53. http://dx.doi.org/10.56748/ejse.182281.

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Water pipeline condition monitoring is a challenging task that requires in-depth research and investigation. Leakages in pipelines can waste large quantities of water daily and affect the quality of the water supply. Detection, quantification, and accurate localisation of leaks can significantly improve the service delivered. In this context, a ‘contact-less’ optical fibre sensor package was developed with the ability to measure pressure and detect vibration in pipe. This study provides a description of the developed sensor and presents the findings from a set of experiments with the sensor package deployed inside a pressurised pipe. Results indicate that the proposed sensing strategy for leak detection and quantification is robust and promising.

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Lorenzini, Marta, Wansoo Kim, Elena De Momi, and Arash Ajoudani. "An Online Method to Detect and Locate an External Load on the Human Body with Applications in Ergonomics Assessment." Sensors 20, no. 16 (August 10, 2020): 4471. http://dx.doi.org/10.3390/s20164471.

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In this work, we propose an online method to detect and approximately locate an external load induced on the body of a person interacting with the environment. The method is based on a torque equilibrium condition on the human sagittal plane, which takes into account a reduced-complexity model of the whole-body centre of pressure (CoP) along with the measured one, and the vertical component of the ground reaction forces (vGRFs). The latter is combined with a statistical analysis approach to improve the localisation accuracy, (which is subject to uncertainties) to the extent of the industrial applications we target. The proposed technique eliminates the assumption of known contact position of an external load on the human limbs, allowing a more flexible online body-state tracking. The accuracy of the proposed method is first evaluated via a simulation study in which various contact points on different body postures are considered. Next, experiments on human subjects with three different contact locations applied to the human body are presented, revealing the validity of the proposed methodology. Lastly, its benefit in the estimation of human dynamic states is demonstrated. These results add another layer to the online human ergonomics assessment framework developed in our laboratory, extending it to more realistic and varying interaction conditions.

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Smith, D. Fitzroy. "Case report – Carcinoid Syndrome: Two case reports from Reserve Unit." Journal of The Royal Naval Medical Service 97, no. 2 (June 2011): 66–71. http://dx.doi.org/10.1136/jrnms-97-66.

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AbstractCarcinoid tumours are uncommon and carcinoid syndrome is likely to be encountered only occasionally during a clinical career outside the Neuro-endocrine and related specialties. Two cases of carcinoid syndrome are described in Royal Naval Reserve (RNR) personnel presenting simultaneously in the same unit. Both had long histories and, despite early contact with medical staff, had for some time been dismissed as having trivial complaints. Both have responded well to treatment, though neither has been able to have curative surgery. The current methods of diagnosis which allow much earlier identification and localisation of these tumours are discussed. We also review the management options now available which will control disease and allow the patient to pursue their chosen career, be it military or civil.

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Rafiee, A., M. Vinches, and C. Bohatier. "Comportement mécanique d’un massif rocheux fracturé considéré comme un assemblage d’éléments discrets : exemple d’une modélisation par la méthode Non-Smooth Contact Dynamics." Revue Française de Géotechnique, no. 128 (2009): 27–34. http://dx.doi.org/10.1051/geotech/2009128027.

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Biermans, W., I. Bernaert, M. De Bie, B. Nijs, and W. Jacob. "Ultrastructural localisation of creatine kinase activity in the contact sites between inner and outer mitochondrial membranes of rat myocardium." Biochimica et Biophysica Acta (BBA) - Bioenergetics 974, no. 1 (April 1989): 74–80. http://dx.doi.org/10.1016/s0005-2728(89)80167-7.

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Pedersen, Hanne Skovsgaard, Henrik Callesen, Peter Løvendahl, Fenghua Chen, Jens Randel Nyengaard, Nanett Kvist Nikolaisen, Peter Holm, and Poul Hyttel. "Ultrastructure and mitochondrial numbers in pre- and postpubertal pig oocytes." Reproduction, Fertility and Development 28, no. 5 (2016): 586. http://dx.doi.org/10.1071/rd14220.

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Prepubertal pig oocytes are associated with lower developmental competence. The aim of this experiment was to conduct an exhaustive survey of oocyte ultrastructure and to use a design-unbiased stereological approach to quantify the numerical density and total number of mitochondria in oocytes with different diameters from pre- and postpubertal pigs. The ultrastructure of smaller prepubertal immature oocytes indicated active cells in close contact with cumulus cells. The postpubertal oocytes were more quiescent cell types. The small prepubertal oocytes had a lower total mitochondrial number, but no differences were observed in mitochondrial densities between groups. Mature postpubertal oocytes adhered to the following characteristics: presence of metaphase II, lack of contact between cumulus cells and oocyte, absence of rough endoplasmic reticulum and Golgi complexes, peripheral location of cortical granules and central localisation of mitochondria, vesicles and lipid droplets. Prepubertal oocytes displayed more variation. The ultrastructure of large pre- and postpubertal oocytes was compatible with higher developmental competence, whereas that of smaller prepubertal oocytes could explain their reduced capacity. The higher number of mitochondria in large pre- and postpubertal oocytes could have an influence on oocyte competence, by increasing the pool of mitochondria available for early embryonic development.

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Sincock, P. M., S. Fitter, R. G. Parton, M. C. Berndt, J. R. Gamble, and L. K. Ashman. "PETA-3/CD151, a member of the transmembrane 4 superfamily, is localised to the plasma membrane and endocytic system of endothelial cells, associates with multiple integrins and modulates cell function." Journal of Cell Science 112, no. 6 (March 15, 1999): 833–44. http://dx.doi.org/10.1242/jcs.112.6.833.

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The Transmembrane 4 Superfamily member, PETA-3/CD151, is ubiquitously expressed by endothelial cells in vivo. In cultured human umbilical vein endothelial cells PETA-3 is present on the plasma membrane and predominantly localises to regions of cell-cell contact. Additionally, this protein is abundant within an intracellular compartment which accounts for up to 66% of the total PETA-3 expressed. Intracellular PETA-3 showed colocalisation with transferrin receptor and CD63 suggesting an endosomal/lysosomal localisation which was supported by immuno-electronmicroscopy studies. Co-immunoprecipitation experiments investigating possible interactions of PETA-3 with other molecules demonstrated associations with several integrin chains including beta1, beta3, beta4, (alpha)2, (alpha)3, (alpha)5, (alpha)6 and provide the first report of Transmembrane 4 Superfamily association with the (alpha)6beta4 integrin. Using 2-colour confocal microscopy, we demonstrated similar localisation of PETA-3 and integrin chains within cytoplasmic vesicles and endothelial cell junctions. In order to assess the functional implications of PETA-3/integrin associations, the effect of anti-PETA-3 antibodies on endothelial function was examined. Anti-PETA-3 mAb inhibited endothelial cell migration and modulated in vitro angiogenesis, but had no detectable effect on neutrophil transendothelial migration. The broad range of integrin associations and the presence of PETA-3 with integrins both on the plasma membrane and within intracellular vesicles, suggests a primary role for PETA-3 in regulating integrin trafficking and/or function.

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Weryszko-Chmielewska, Elżbieta, and Mirosława Chwil. "Localisation of furanocoumarins in the tissues and on the surface of shoots of Heracleum sosnowskyi." Botany 95, no. 11 (November 2017): 1057–70. http://dx.doi.org/10.1139/cjb-2017-0043.

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Heracleum sosnowskyi Manden. was introduced in Poland as a fodder plant. Currently, it is regarded as an invasive plant posing a health hazard to humans and animals and a threat to native flora. The aim of the study was to localise furanocoumarins in the stem and leaf tissues. The investigations were carried out using light, fluorescence, and scanning electron microscopy as well as histochemical assays. The epidermis of the analysed organs bears live, non-capitate hairs with variable length, which contain lipids, essential oils, polysaccharides, tannins, and furanocoumarins. The observations performed with scanning electron microscopy revealed the presence of a foamy substance and furanocoumarin crystals on the surface of the trichomes and other epidermal cells, as well as in the parenchyma cells. Characteristic furanocoumarin autofluorescence was present in the epidermis and on its surface, as well as in the subepidermal parenchyma. Secondary fluorescence was emitted by furanocoumarins in different leaf petiole tissues: psoralen, bergapten, and xanthotoxin. We have detected for the first time the presence of furanocoumarins in different tissues of leaves in H. sosnowskyi. Furanocoumarins were also abundantly present on the epidermal surface of cells. This explains why the contact with the plant is dangerous to humans and results in development of photodermatoses.

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39

Chadfeau, Calypso, Sayed Hashim Mohseni, Safiullah Omary, Vincent Steiner, Essia Belhaj, Christophe Fond, and Françoise Feugeas. "Influence d’un bioadjuvant sur l’adhésion du ciment sur parois coffrantes et évaluation de l’effet de la rugosité des parois coffrantes." Matériaux & Techniques 108, no. 3 (2020): 301. http://dx.doi.org/10.1051/mattech/2020031.

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L’objectif de ce travail est de comprendre comment l’adhésion entre le ciment et le coffrage est influencée par la morphologie de la surface du coffrage et l’ajout d’un bioadjuvant. L’ancrage mécanique de la pâte cimentaire est en effet lié à la rugosité de surface du coffrage. Une procédure de caractérisation morphologique des surfaces en contact, coffrage et ciment, est développée par microscopie interférométrique. Elle permet de retenir une échelle d’observation pour laquelle les valeurs des paramètres d’états de surface Sa, Sq, Sdr, Vvc et Vvv, sont représentatifs de la morphologie de surface. Trois états de surface de coffrage différents sont obtenus par polissage et sont caractérisés à l’échelle d’observation. Les paramètres de surfaces sont corrélés avec les performances au décoffrage pour ces trois états de surface. L’action d’un bioadjuvant sur les phénomènes d’adhésion tant au niveau des efforts de décoffrage que de la qualité de parement est évaluée pour trois taux d’incorporation de bioadjuvant. Les résultats mettent en évidence qu’un degré de polissage spécifique combiné à l’utilisation d’un taux de bioadjuvant minimum dans la pâte cimentaire permettent d’atteindre des performances au décoffrage équivalentes à celles obtenues avec un agent décoffrant classique.

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40

Jumpee, Chayanit, Chanakarn Onnomdee, Putthiporn Charoenphun, Phiphat Phruksarojanakun, and Krisanat Chuamsaamarkkee. "Radiation safety aspects of 90Y bremsstrahlung radiation produced from radiation shielding apparatus using the Monte Carlo simulation." Nuclear Technology and Radiation Protection 36, no. 3 (2021): 255–60. http://dx.doi.org/10.2298/ntrp2103255j.

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Selective internal radiation therapy using an 90Y labelled microsphere is increasingly used to treat hepatocellular carcinoma. Based on its properties, 90Y can produce bremsstrahlung radiation which is essential for post-treatment localisation and dosimetry. However, bremsstrahlung radiation could lead to an increase of radiation exposure of radiation workers. The aim of this work was to determine the 90Y bremsstrahlung radiation produced from the polymethyl methacrylate radiation shielding apparatus using the Monte Carlo simulation. A scintillation detector with a 137Cs standard source was used to validate the Monte Carlo simulation. After validation, the 90Y bremsstrahlung photons spectrum produced from the radiation shielding apparatus was simulated. The radiation equivalent dose rates to the head, neck, body, lower extremities at a distance of 30 centimeters, and finger (contact with the knob) were estimated to be 4.9 ? 0.6, 6.2 ? 0.1, 18.9 ? 0.4, 13.1 ? 0.6, and 3900 ? 50 ?Svh?1, respectively. The corresponding annual doses exceeded the limit when radiation workers performed 2631, 1563, 769, and 515 cases per year with contact the knob 3, 5, 10, and 15 minutes per case, respectively. The simulation result showed that radiation exposure of radiation workers and the number of selective internal radiation therapy procedures performed should be considered.

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Kozłowski, M., J. Wilczak, T. Motyl, and M. Gajewska. "Role of extracellular matrix and prolactin in functional differentiation of bovine BME-UV1 mammary epithelial cells." Polish Journal of Veterinary Sciences 14, no. 3 (September 1, 2011): 433–42. http://dx.doi.org/10.2478/v10181-011-0064-1.

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Role of extracellular matrix and prolactin in functional differentiation of bovine BME-UV1 mammary epithelial cells Interactions between extracellular matrix (ECM) and epithelial cells are necessary for proper organisation and function of the epithelium. In the present study we show that bovine mammary epithelial cell line BME-UV1 cultured on ECM components, commercially available as Matrigel™, constitutes a good model for studying mechanisms controlling functional differentiation of the bovine mammary gland. In contact with Matrigel BME-UV1 cells induce apicobasal polarity, and within 16 days form three dimensional (3D) acinar structures with a centrally localized hollow lumen, which structurally resemble mammary alveoli present in the functionally active mammary gland. We have shown that the 3D culture system enables a high expression and proper localisation of integrin receptors and tight junction proteins in BME-UV1 cells to be induced. This effect was not obtained in cells grown in the classical 2D culture system on plastic. Moreover, ECM highly stimulated the synthesis of one of the major milk proteins, β-casein, even in the absence of prolactin. Our results show that contact with ECM plays an important role in the lactogenic activity of bovine MECs, however, prolactin is necessary for the efficient secretion of milk proteins.

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Untergehrer, G., D. Jordan, E. F. Kochs, and G. Schneider. "Source localisation of contact heat evoked potentials (CHEP) indicates different effects of propofol and remifentanil on cerebral processing of painful stimuli." European Journal of Anaesthesiology 28 (June 2011): 3–4. http://dx.doi.org/10.1097/00003643-201106001-00010.

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Mege, R. M., D. Goudou, C. Diaz, M. Nicolet, L. Garcia, G. Geraud, and F. Rieger. "N-cadherin and N-CAM in myoblast fusion: compared localisation and effect of blockade by peptides and antibodies." Journal of Cell Science 103, no. 4 (December 1, 1992): 897–906. http://dx.doi.org/10.1242/jcs.103.4.897.

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The expression and distribution of two cell adhesion molecules, N-cadherin and N-CAM, at the surface of cultured leg muscle cells from 11-day-old chicken embryos were studied and compared. N-cadherin, which was expressed by fusing myoblasts, was down-regulated on old myotubes while N-CAM was still present. Both molecules, as viewed by confocal microscopy, appeared to have coaccumulated at the areas of contact between fusing myoblasts. However, immunogold electron microscopy did not reveal significant colocalization of N-cadherin and N-CAM, and their segregation after antibody-induced patching suggested the absence of direct interactions between N-cadherin and N-CAM. The role of the Ca2+ dependent cell adhesion molecule N-cadherin in myogenesis was investigated. Myoblast fusion was inhibited (1) with a synthetic peptide containing the H-A-V sequence and (2) with a monoclonal anti-N-cadherin antibody, demonstrating that N-cadherin-mediated cell adhesion is required for myoblast fusion. Under the same conditions no effect of anti-N-CAM antibodies was observed. Taken together these observations suggest that N-cadherin, acting independently from N-CAM, is a major cell adhesion molecule involved in embryonic myoblast fusion in vitro.

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Fleming, T. P., M. Hay, Q. Javed, and S. Citi. "Localisation of tight junction protein cingulin is temporally and spatially regulated during early mouse development." Development 117, no. 3 (March 1, 1993): 1135–44. http://dx.doi.org/10.1242/dev.117.3.1135.

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The molecular maturation of the tight junction in the mouse early embryo has been investigated by monitoring the distribution of cingulin, a 140 × 10(3) M(r) peripheral (cytoplasmic) membrane constituent of the junction, at different stages of development and in different experimental situations. Although tight junction formation does not begin until compaction at the 8-cell stage, cingulin is detectable in oocytes and all stages of cleavage, a factor consistent with our biochemical analysis of cingulin expression (Javed et al., 1992, Development 117, 1145–1151). Using synchronised egg and embryo stages and isolated cell clusters, we have identified three sites where cingulin is localised, the cytocortex, punctate cytoplasmic foci and tight junctions themselves. Cytocortical cingulin is present at the cumulus-oocyte contact site (both cell types), in unfertilised and fertilised eggs and in cleavage stages up to 16-cell morulae, particularly at microvillous domains on the embryo outer surface (eg. apical poles at compaction). Embryo manipulation experiments indicate that cortical cingulin is labile and dependent upon cell interactions and therefore is not merely an inheritance from the egg. Cingulin cytoplasmic foci are evident only in outer cells (prospective trophectoderm) from the 32-cell stage, just prior to cavitation, and decline from approx. 8 hours after cavitation has initiated. The appearance of these foci is insensitive to cycloheximide treatment and they colocalise with apically derived endocytic vesicles visualised by FITC-dextran, indicating that the foci represent the degradation of cytocortical cingulin by endocytic turnover. Cingulin is detectable at the tight junction site between blastomeres usually from the 16-cell stage, although earlier assembly occurs in a minority (up to 20%) of specimens. Cingulin assembly at the tight junction is sensitive to cycloheximide and is identifiable approx. 10 hours after cell adhesion is initiated and ZO-1 protein assembles. Collectively, our results indicate that (i) cingulin from nonjunctional sites does not contribute to tight junction assembly and (ii) the molecular maturation of the junction appears to occur progressively over at least two cell cycles.

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Marot, Didier, Bikram Oli, Rachel Gelet, and Fateh Bendahmane. "Nouveau dispositif pour l’étude de la suffusion suivant différents états mécaniques." Revue Française de Géotechnique, no. 178 (2024): 3. http://dx.doi.org/10.1051/geotech/2024006.

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Les instabilités et les ruptures que peuvent subir les digues et les barrages en remblais sont très majoritairement dues aux processus d’érosion externe (surverse) et d’érosion interne (renard hydraulique, érosion régressive, érosion de contact ou suffusion). Cette étude porte sur la suffusion qui peut mobiliser la fraction fine de sols pulvérulents ou faiblement cohésifs. Ce processus complexe combine trois mécanismes : le détachement, le transport et l’éventuelle filtration des particules fines. De nombreux critères ont été proposés dans littérature, pour caractériser la susceptibilité à la suffusion, en considérant uniquement la distribution granulométrique et éventuellement la densité du sol. Toutefois, plusieurs études ont montré que l’initiation et le développement de la suffusion dépendent aussi du chemin de chargement hydraulique. Par ailleurs, chacun des trois mécanismes susmentionnés dépend du chargement mécanique subi par le sol. Dans ce contexte, un dispositif expérimental a été développé afin de caractériser la sensibilité vis-à-vis de la suffusion, de quatre sols pulvérulents à distribution lacunaire (composé de sable et de gravier), en contrôlant l’état mécanique et le chemin de chargement hydraulique. Les essais sont réalisés à l’aide du banc triaxial dédié qui permet d’appliquer à l’échantillon (diamètre : 100 mm ; hauteur : 200 mm) un écoulement vertical descendant. La charge hydraulique appliquée est augmentée automatiquement, par faibles incréments et suivant le même chemin pour tous les essais. Les échantillons sont tous consolidés sous une même contrainte effective moyenne, mais la valeur du déviateur de contrainte est propre à chaque essai. Enfin des essais sont menés en conditions œdométriques. L’interprétation des évolutions de conductivité hydraulique et de taux d’érosion permet tout d’abord d’identifier 4 étapes successives : initiation, filtration, débourrage et état permanent caractérisant la fin du processus de suffusion. Chacune de ces étapes est ensuite étudiée à l’aide de différentes méthodes interprétatives. À la fin de chaque essai, les échantillons sont découpés en 4 couches afin de mesurer les évolutions de distribution granulométrique. Les résultats obtenus soulignent la présence d’écoulements préférentiels circonférentiels pour l’essai réalisé en conditions œdométriques, ce qui conduit à une légère surestimation de la sensibilité à la suffusion. En conditions triaxiales, l’influence sur la suffusion du déviateur de contrainte apparaît limitée, notamment en regard de l’influence du pourcentage de sable. Enfin la confrontation de ces résultats montre que contrairement à l’approche énergétique, l’approche en conductivité hydraulique ne permet pas de détecter toutes les étapes pour tous les essais.

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Turlapati, Sri Harsha, Dino Accoto, and Domenico Campolo. "Haptic Manipulation of 3D Scans for Geometric Feature Enhancement." Sensors 21, no. 8 (April 12, 2021): 2716. http://dx.doi.org/10.3390/s21082716.

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Localisation of geometric features like holes, edges, slots, etc. is vital to robotic planning in industrial automation settings. Low-cost 3D scanners are crucial in terms of improving accessibility, but pose a practical challenge to feature localisation because of poorer resolution and consequently affect robotic planning. In this work, we address the possibility of enhancing the quality of a 3D scan by a manual ’touch-up’ of task-relevant features, to ensure their automatic detection prior to automation. We propose a framework whereby the operator (i) has access to both the actual work-piece and its 3D scan; (ii) evaluates the missing salient features from the scan; (iii) uses a haptic stylus to physically interact with the actual work-piece, around such specific features; (iv) interactively updates the scan using the position and force information from the haptic stylus. The contribution of this work is the use of haptic mismatch for geometric update. Specifically, the geometry from the 3D scan is used to predict haptic feedback at a point on the work-piece surface. The haptic mismatch is derived as a measure of error between this prediction and the real interaction forces from physical contact at that point on the work-piece. The geometric update is driven until the haptic mismatch is minimised. Convergence of the proposed algorithm is first numerically verified on an analytical surface with simulated physical interaction. Error analysis of the surface position and orientations were also plotted. Experiments were conducted using a motion capture system providing sub-mm accuracy in position and a 6 axis F/T sensor. Missing features are successfully detected after the update of the scan using the proposed method in an experiment.

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Stranieri, Angelica, Monica Probo, Maria C. Pisu, Alberto Fioletti, Sara Meazzi, Maria E. Gelain, Federico Bonsembiante, Stefania Lauzi, and Saverio Paltrinieri. "Preliminary investigation on feline coronavirus presence in the reproductive tract of the tom cat as a potential route of viral transmission." Journal of Feline Medicine and Surgery 22, no. 2 (March 22, 2019): 178–85. http://dx.doi.org/10.1177/1098612x19837114.

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Objectives Feline infectious peritonitis (FIP) is an immune-mediated disease initiated by feline coronavirus (FCoV) infection. To date, the only proven route of transmission is the faecal–oral route, but a possible localisation of FCoV in the reproductive tract of tom cats is of concern, owing to the involvement of the male reproductive tract during FIP and to the presence of reproduction disorders in FCoV-endemic feline catteries. The aim of the study was to investigate the presence and localisation of FCoV in semen and/or in the reproductive tract of tom cats, and its possible association with seroconversion and viraemic phase. Methods Blood, serum, semen and/or testicle samples were obtained from 46 tom cats. Serology was performed on 38 serum samples, nested reverse transcriptase PCR (nRT-PCR) and reverse transcriptase quantitative PCR (RT-qPCR) were performed on 39 blood samples and on 17 semen samples, and histology, immunohistochemistry and nRT-PCR were performed on 39 testicles. Results Twenty-four of 38 serum samples were positive on serology. Semen samples were negative on RT-PCR and RT-qPCR for FCoV, while all blood samples were negative at both molecular methods, except for one sample positive at RT-qPCR with a very low viral load. All testicles were negative at immunohistochemistry, while six were positive at nRT-PCR for FCoV. Serology and blood PCR results suggest that the virus was present in the environment, stimulating transient seroconversion. FCoV seems not to localise in the semen of tom cats, making the venereal route as a way of transmission unlikely. Although viral RNA was found in some testicles, it could not be correlated with the viraemic phase. Conclusions and relevance In the light of these preliminary results, artificial insemination appears safer than natural mating as it eliminates the direct contact between animals, thus diminishing the probability of faecal–oral FCoV transmission.

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48

Zhang, Yi, Sébastien Gilbert, and Dominique Regallet. "Essais et analyses géotechniques sur les argiles plastiques du Sparnacien du Bassin parisien." Revue Française de Géotechnique, no. 170 (2022): 5. http://dx.doi.org/10.1051/geotech/2021030.

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Les argiles plastiques d’âge Sparnacien (Yprésien – Eocène inférieur) présentent un enjeu géotechnique majeur pour le projet Grand Paris Express, un des plus grands projets de métro en cours de construction en Europe. Ces argiles plastiques se trouvent souvent à grande profondeur. Elles sont connues comme imperméables, normalement consolidées ou surconsolidées, gonflantes en affleurement. Cependant, leurs caractéristiques mécaniques sont peu connues, et leur mécanisme de gonflement est complexe car il dépend des caractéristiques physico-chimiques des minéraux constituant ces argiles, ainsi que de leurs états mécaniques et hydriques. Quelques retours d’expériences, parfois accidentels, ont montré des déformations importantes de cette couche géologique, avec la présence locale de poches de sables ou de lithofaciès sableux. Afin de dimensionner correctement les ouvrages en contact avec cette couche, de nombreux essais in situ et en laboratoire ont été réalisés pour mieux appréhender le comportement de ces argiles plastiques. Cet article présente d’abord le contexte géologique et la synthèse des essais sur 3 zones représentatives sur les lignes 14 et 15, à savoir : le Coteau d’Issy à Issy-Les-Moulineaux (L15 Sud-Ouest), la vallée de la Bièvre à la Maison Blanche dans Paris 13e arrondissement (L14 Sud) et la vallée et les plateaux de la Marne à Saint-Maur et Créteil (L15 Sud-Est). Des analyses géotechniques des essais ont été ensuite effectuées zone par zone afin de mieux connaître les comportements mécanique et hydrique, ainsi que la variabilité spatiale, de ces argiles plastiques.

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Pountney, D., G. Trugnan, M. Bourgeois, and C. Beaumont. "The identification of ferritin in the nucleus of K562 cells, and investigation of a possible role in the transcriptional regulation of adult beta-globin gene expression." Journal of Cell Science 112, no. 6 (March 15, 1999): 825–31. http://dx.doi.org/10.1242/jcs.112.6.825.

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We studied the subcellular distribution of ferritin in K562 cells by immunofluorescence techniques and have made a reappraisal of a direct binding interaction between ferritin and the proximal promoter region of the human beta-globin gene, as previously mentioned in the literature. Confocal microscopy indicates that ferritin, the iron-storage protein, is present in the nucleus of K562 cells, in addition to its expected cytoplasmic localisation. The stain distribution suggests that it is not directly associated with the nuclear matrix. Using a gel mobility shift assay, a protein that cross-reacts with monoclonal ferritin antibodies competitively binds to a double-stranded oligonucleotide spanning the region situated 150 base pairs upstream from the beta-globin transcription start site. Despite this antibody cross-reactivity, the protein is unlike cytosolic ferritin as it appears to be highly sensitive to both temperature and freeze-thaw cycles, and UV-crosslinking experiments indicate that the molecular mass of the protein factor lies between 90 and 100 kDa. In conclusion, while the intranuclear location of ferritin is described in the present study, ferritin is not in direct contact with the beta-globin promoter region.

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Ahmad, Usama Sharif, Jutamas Uttagomol, and Hong Wan. "The Regulation of the Hippo Pathway by Intercellular Junction Proteins." Life 12, no. 11 (November 5, 2022): 1792. http://dx.doi.org/10.3390/life12111792.

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The Hippo pathway is an evolutionarily conserved pathway that serves to promote cell death and differentiation while inhibiting cellular proliferation across species. The downstream effectors of this pathway, yes-associated protein (YAP) and transcriptional co-activator with PDZ-binding motif (TAZ), are considered vital in promoting the output of the Hippo pathway, with activation of upstream kinases negatively regulating YAP/TAZ activity. The upstream regulation of the Hippo pathway is not entirely understood on a molecular level. However, several studies have shown that numerous cellular and non-cellular mechanisms such as cell polarity, contact inhibition, soluble factors, mechanical forces, and metabolism can convey external stimuli to the intracellular kinase cascade, promoting the activation of key components of the Hippo pathway and therefore regulating the subcellular localisation and protein activity of YAP/TAZ. This review will summarise what we have learnt about the role of intercellular junction-associated proteins in the activation of this pathway, including adherens junctions and tight junctions, and in particular our latest findings about the desmosomal components, including desmoglein-3 (DSG3), in the regulation of YAP signalling, phosphorylation, and subcellular translocation.

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Journal articles on the topic 'Mécanique du contact – Localisation'

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