Добірка наукової літератури з теми "Cellular tests"
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Статті в журналах з теми "Cellular tests":
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Vaganov, A. A., A. S. Timonin, and I. I. Sidelnikov. "Hydraulic tests of cellular packing." Chemical and Petroleum Engineering 46, no. 11-12 (March 2011): 699–702. http://dx.doi.org/10.1007/s10556-011-9405-2.
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Chirumbolo, Salvatore. "Immunotherapy in allergy and cellular tests." Human Vaccines & Immunotherapeutics 10, no. 6 (May 2, 2014): 1595–610. http://dx.doi.org/10.4161/hv.28592.
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Ariza, Adriana, Maria Montanez, Tahia Fernandez, James Perkins, and Cristobalina Mayorga. "Cellular Tests for the Evaluation of Drug Hypersensitivity." Current Pharmaceutical Design 22, no. 45 (January 17, 2017): 6773–83. http://dx.doi.org/10.2174/1381612822666161107165917.
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Sanz, Maria, Pedro Gamboa, and A. De Weck. "Cellular Tests in the Diagnosis of Drug Hypersensitivity." Current Pharmaceutical Design 14, no. 27 (September 1, 2008): 2803–8. http://dx.doi.org/10.2174/138161208786369722.
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Dowling, V. P., and K. G. Martin. "Radiant Panel Fire Tests on Cellular Plastics Insulation." Journal of Thermal Insulation 8, no. 4 (April 1985): 314–38. http://dx.doi.org/10.1177/109719638500800407.
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Vaganov, A. A., and A. S. Timonin. "Heat- and mass-transfer tests of cellular packing." Chemical and Petroleum Engineering 46, no. 11-12 (March 2011): 686–91. http://dx.doi.org/10.1007/s10556-011-9402-5.
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Bathgate, AJ, JN Plevris, MM Dollinger, and PC Hayes. "Skin tests predict acute cellular rejection in liver transplantation." Gastroenterology 114 (April 1998): A1209. http://dx.doi.org/10.1016/s0016-5085(98)84907-x.
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Bathgate, A. J., J. N. Plevris, M. M. Dollinger, and P. C. Hayes. "SKIN TESTS PREDICT ACUTE CELLULAR REJECTION IN LIVER TRANSPLANTATION." Transplantation 67, no. 7 (April 1999): S260. http://dx.doi.org/10.1097/00007890-199904150-01038.
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Sabovljev, S. A., W. A. Cramp, P. D. Lewis, G. Harris, KeithE Halnan, and J. Lambert. "USE OF RAPID TESTS OF CELLULAR RADIOSENSITIVITY IN RADIOTHERAPEUTIC PRACTICE." Lancet 326, no. 8458 (October 1985): 787. http://dx.doi.org/10.1016/s0140-6736(85)90674-9.
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Buyuktiryaki, Betul, and Alexandra F. Santos. "Food allergy severity predictions based on cellular in vitro tests." Expert Review of Molecular Diagnostics 20, no. 7 (July 2, 2020): 679–91. http://dx.doi.org/10.1080/14737159.2020.1782192.
Дисертації з теми "Cellular tests":
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Zhang, Ganggang. "Tests des composés de nacre sur l'activité des ostéoblastes et leur identification." Thesis, Université de Lorraine, 2017. http://www.theses.fr/2017LORR0051/document.
Анотація:
Avec de nombreuses qualités exceptionnelles (biocompatible et ostéogénique), la nacre représente un biomatériau naturel comme substitut osseux. Mais les composés ostéogéniques dans la nacre ne sont pas encore connus. Nos travaux visent à l’identification des composés ostéogéniques de la nacre. L’ESM (éthanol soluble matrix) est un extrait de la nacre qui est démontré ostéogénique. A partir d’ESM, nous avons essayé plusieurs approches pour cibler et identifier ces composés. Grâce au couplage des cellules MC3T3-E1 et d’ostéoblastes humains arthrosiques, nous avons démontré que la partie cationique d’ESM est ostéogénique, sans interaction avec la partie anionique. Le calcium joue un rôle dans l’activité ostéogénique d’ESM. Ensuite, nous avons créé une lignée cellulaire exprimant de manière stable un plasmide contenant un gène rapporteur ostéogénique (ATDC5 pMetLuc2 ColX promoteur). Grâce à cette lignée, nous avons découvert que les lipides et les sucres présents dans l’ESM ont un effet ostéogénique. Les peptides précipités par TCA sont aussi démontrés ostéogéniques, et ont conduit à leur identification partielle par LC-MS. Ces résultats nous permettent d’avancer plus loin et plus rapidement vers l’identification des composés ostéogéniques de la nacre et vers les applications de la nacre en orthopédie cliniqueWith many exceptional qualities (biocompatible and osteogenic), nacre represents a natural biomaterial as a bone substitute. However, the osteogenic compounds in nacre are not yet known. Our work aims at the identification of the osteogenic compounds in nacre. The ESM (soluble ethanol matrix) is an extract of nacre that is shown to be osteogenic. From the ESM, we have tried several approaches to target and identify these compounds. Thanks to the coupling of MC3T3-E1 cells and the human osteoarthritis osteoblasts, we demonstrated that the cationic part of the ESM is osteogenic, without interaction with the anionic part. Calcium plays a role in the osteogenic activity of the ESM. Then, we created a cell line stably expressing a plasmid containing an osteogenic reporter gene (ATDC5 pMetLuc2 ColX promoter). Thanks to this cell line, we found out that the lipids and sugars in the ESM have an osteogenic effect. The peptides precipitated by TCA are also demonstrated to be osteogenic, which have led to their partial identification by LC-MS. These results allow us to move farther and faster towards the identification of osteogenic compounds in nacre and the applications of nacre in clinical orthopaedics
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Barbier, Lucie. "Study of cellular mechanisms allowing dendritic cell migration in restricted spaces." Thesis, université Paris-Saclay, 2020. http://www.theses.fr/2020UPASL028.
Анотація:
En cas d'infection, les cellules dendritiques matures (CDm) migrent des tissus périphériques vers les ganglions lymphatiques où ils déclenchent la réponse immunitaire adaptative. Ce déplacement impose une série de contraintes physiques sur les CDm. Au niveau cellulaire, la migration des CDm repose sur la contractilité du cytosquelette d’actine et de myosine. Toutefois, la réponse mécanique spécifique qui permet aux CDm d'adapter leur mode de migration aux contraintes physiques n'a pas été entièrement caractérisée. Dans ce travail, nous avons combiné une série d'approches, des outils microfluidiques aux modèles ex vivo, pour disséquer les réarrangements du cytosquelette nécessaires à l’adaptation du mode de migration des cellules dendritiques aux propriétés physiques de leur microenvironnement. Nous avons montré que les CDm sont capables de maintenir une vitesse constante tout en migrant à différents niveaux de confinement. Cela révèle la capacité des CDm à adapter leur mode de migration en réponse aux changements dans la géométrie de leur microenvironnement. Au niveau cellulaire, le confinement dans les microcanaux induit un remodelage rapide et spécifique du cytosquelette d’actine et de myosine. Il est essentiel à la plasticité migratoire des CDm et optimise le déplacement de ces cellules dans des environnements 3D complexes. Ces travaux conduisent à une meilleure compréhension des mécanismes permettant aux CDm d’adapter leur motilité face à des structures tissulaires spécifiques. Ils permettront de mieux appréhender le contrôle de la migration des leucocytes dans des espaces confinés et pouvoir ainsi la moduler avec précision afin de favoriser ou de prévenir les réponses immunitaireUpon infection, mature dendritic cells (mDCs) migrate from peripheral tissue to lymph nodes and initiate the adaptive immune response. This fast and tightly regulated process imposes a series of physical constraints and is tuned by different microenvironmental factors, such as the physical properties of the tissue. Mechanistically, mDCs migration relies on actomyosin flow and contractility, which are dependent on non‐muscular Myosin IIA activity. However, the specific mechanoresponse that allows mDCs to adapt their migration machinery to irregular 3D landscapes has not been fully characterized. In this work, we combined a series of approaches, from micro‐fabricated devices to ex vivo skin models, to dissect the cytoskeleton rearrangements used by mDCs to overcome the physical barriers imposed by the tissue. We have shown mDCs are able to maintain a constant speed while migrating at different levels of confinement. This reveals the extreme capacity of mDCs to adapt their migration machinery in response to changes in the geometry of their microenvironment. At the cellular level, confinement in microchannels induces a fast and specific actomyosin remodelling in mDCs. This reveals a complete actomyosin rearrangement triggered by confinement, which is essential for mDCs migratory plasticity that allows these cells to move in intricate 3D geometries. The full understanding of how mDCs and other leukocytes adapt their motility to specific tissue structures will provide better knowledge on how cell migration is controlled in confined spaces and new insight to finely tune their migration to promote or prevent immune responses
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Hansson, Helene. "Methodological aspects on anti-nuclear antibody determination in canine autoimmunity and in vitro studies of antigen-specific cellular responses /." Uppsala : Swedish Univ. of Agricultural Sciences (Sveriges lantbruksuniv.), 1999. http://epsilon.slu.se/avh/1999/91-576-5439-5.pdf.
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Görge, Julie. "Immunodiagnostic par agglutination magnétique." Phd thesis, Université Pierre et Marie Curie - Paris VI, 2011. http://pastel.archives-ouvertes.fr/pastel-00610317.
Анотація:
Les tests de diagnostic ont pour but de détecter et de quantifier un ou plusieurs analytes en milieu complexe. Depuis les années 80, leur évolution s'est concentrée sur la détection de très faibles quantités d'analytes. Actuellement, cette ligne directrice subsiste mais en parallèle les développements se portent sur de nouveaux objectifs comme la mise au point de tests simples, rapides, transportables et sensibles afin de répondre au mieux aux attentes des nouveaux marchés : le point of care et les pays émergents. Au cours de ce travail, nous nous sommes confrontés à ces nouvelles problématiques. Nous avons choisi d'améliorer la sensibilité du test d'agglutination magnétique précédemment développé au laboratoire en raison de sa simplicité (test homogène) et de sa rapidité (manipulation de billes magnétiques). Nous avons montré que deux paramètres conditionnaient le seuil de détection de ce test à savoir le bruit (variabilité du signal sans antigène) et le signal émis par les billes. Le premier facteur dépend principalement du nombre de billes et le deuxième nous a amené à travailler avec de grandes billes nécessitant une nouvelle méthode de détection, la cytométrie en flux. Le gain en sensibilité n'a pas été clairement démontré en raison de la très faible réactivité des billes utilisées (500 fois moins réactives que les billes "habituelles"). Une chose est sûre, de grandes billes améliorent le signal, la cinétique et la thermodynamique au détriment d'une plus faible mobilité des objets sous champ. Sous couvert d'une bonne réactivité, nous nous sommes aperçus que la première étape de notre test d'agglutination devenait thermodynamiquement et cinétiquement limitante aux faibles concentrations en analyte. Dans le cadre du projet européen DetectHIV, nous avons essayé d'une part de franchir ces barrières à travers un système microfluidique et d'autre part de mettre au point un test complètement intégré. De nouvelles technologies ont vu le jour à l'EPFL (plug magnétique) et à DTU (cytométrie sur puce). Le système développé par l'EPFL est thermodynamiquement favorable, valide l'idée de préconcentration mais nécessiterait un nouveau dimensionnement fluidique pour réellement supplanter les tests en volume. L'intégration, quant à elle, a permis d'acquérir un certain savoir faire dans le domaine de la microfluidique, d'identifier les verrous technologiques et de développer un nouveau mode de circulation des fluides. Pour conclure, ce travail a permis de cerner l'évolution possible des tests d'agglutination magnétique. La sensibilité du test originel c'est-à-dire en volume couplé à une détection turbidimétrique est fixée par le bruit de l'appareil de mesure. Ce paramètre étant peu optimisable, seule une augmentation de la taille des billes permettrait d'augmenter significativement la sensibilité du test (un facteur 10 en théorie). Au delà, une détection individuelle des objets via la cytométrie est nécessaire. D'une part, elle permet de travailler avec de gros objets afin d'amplifier grandement le signal et d'autre part, elle permet de s'affranchir du bruit de l'appareil de mesure. Le bruit mesuré est uniquement dû à la comptabilisation des populations, bruit inhérent au test de diagnostic. Avec cette configuration, un gain de sensibilité passe par une diminution du non-spécifique (relatif au comptage des populations) et par une augmentation de la réactivité des "grosses" billes. En dessous de la dizaine de femtomoles, la formation de complexe n'est plus assurée et devient longue, un changement de format fluidique est alors nécessaire. Le nouveau format fluidique testé, la microfluidique, s'avère très prometteur à condition d'intégrer une méthode de détection (cytométrique ou autre) et d'augmenter les débits.
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Delompre, Thomas. "Compréhension des mécanismes de perception sensorielle de compléments nutritionnels sous différentes formulations." Thesis, Bourgogne Franche-Comté, 2021. http://www.theses.fr/2021UBFCK038.
Анотація:
La prise de compléments nutritionnels est utile lorsque l’alimentation quotidienne ne suffit plus à couvrir les besoins de l’organisme en nutriments et en énergie. Les ingrédients actifs de ces produits sont principalement des vitamines, des minéraux, des éléments traces, des extraits de plantes. Le mode d’administration par voie orale est largement plébiscité par les consommateurs, c’est pourquoi les produits sont commercialisés sous forme de comprimés effervescents, à croquer, sous forme de poudres et comprimés à mettre en bouche ou sous formes gélifiées. Outre leur efficacité sur le plan nutritionnel, ces produits doivent satisfaire le consommateur sur le plan organoleptique. Cependant, ces compléments nutritionnels sont souvent décrits avec des défauts de goûts non identifiés qui limitent leur acceptabilité.La caractérisation sensorielle de ces « mauvais goûts », l’identification des composés impliqués et la compréhension des mécanismes à l’origine de leur détection sont un véritable challenge pour les industries concernées. Dans ce travail, une méthodologie basée sur des approches sensorielles et cellulaires a été mise en œuvre afin d’améliorer les connaissances sur la perception des « mauvais goûts » des compléments nutritionnels et mettre en évidence des pistes envisageables pour de nouvelles stratégies de masquage.Pour la caractérisation et la quantification des « mauvais goût », les profils sensoriels de différentes gammes et formes de compléments nutritionnels ont été déterminés par des panels de dégustateurs. Un protocole d’analyse sensorielle adapté à la forme galénique évalué (effervescente ou orodispersible) a permis d’identifier et de quantifier certaines perceptions négatives. Les résultats obtenus démontrent en autre la présence d’une amertume prononcée pour de nombreux compléments nutritionnels, qui pourraient contribuer de manière récurrente à leur « mauvais goût ». Une analyse sensorielle de ces mêmes compléments nutritionnels dans des conditions avec et sans blocage du flux rétronasal a révélé des interactions perceptives positives et/ou négatives entre molécules aromatiques et sapides, dont l’origine bien que discutée reste à démontrer.La corrélation entre les profils sensoriels et les compositions nutritives des compléments nutritionnels a révélé que certains composés actifs comme des vitamines pouvaient être responsable de cette amertume. L’être humain possède 25 structures moléculaires spécialisées dans la reconnaissance des molécules amères que l’on appelle des TAS2Rs. L’utilisation d’un protocole d’expérimentation fonctionnelle in vitro a montré que quatre composés vitaminiques étaient capables d’activer un ou plusieurs TAS2R(s). Parallèlement, nous avons complété cette expérimentation fonctionnelle par des mesures psychométriques de seuil de détection à l’amertume chez l’humain. La comparaison des jeux de données sensoriels et cellulaires a révélé l’impact de la physiologie orale et de l’intégration centrale de l’information sur la perception d’un stimulus gustatif. Les résultats obtenus ont démontré que la combinaison d’une approche cellulaire et sensorielle semblait être une méthode alternative efficace pour évaluer la contribution d’un ou plusieurs composés aux perceptions sensorielles négatives des compléments nutritionnelsTaking nutritional supplements is recommended when a normal diet is no sufficient to maintain a good nutritional status. The active ingredients of these products are mainly vitamins, minerals, trace elements and plant extracts. The oral method of administration is widely preferred by consumers, therefore the products are marketed as effervescent tablets, chewable, orodispersible powders and tablets or gelled forms. In addition to their nutritional effectiveness, these products must meet consumer’s expectations as “taste” or “flavor”. However, these nutritional supplements are often described with not identified taste defects, which limit their acceptability.The sensory characterization of these “off-tastes”, the involved compounds identification and the understanding of the mechanisms at the origin of their detection are a real challenge for industry concerned. In this work, a methodology based on sensory and cellular approaches has been implemented in order to improve knowledge on the perception of nutritional supplements “off-tastes” and to highlight possible options for new masking strategies.For the “off-tastes” characterization and quantification, the sensory profiles of different ranges and forms of nutritional supplements were determined by panels of tasters. A sensory analysis protocol adapted to the galenic form evaluated (effervescent or orodispersible) allows to identify and quantify some negative perceptions. The results obtained also demonstrated the presence of a slightly strong bitterness for many nutritional supplements, which could recurrently contribute to their "off-taste". A sensory analysis of these same nutritional supplements with and without retronasal flow blockage conditions revealed positive and/or negative perceptual interactions between aromatic and sapid molecules whose origin remains to be demonstrated.The correlation between sensory profiles and nutritional supplements compositions revealed that some active ingredients such as vitamins could be involved in their bitterness. In humans, bitter substances are detected in the mouth by 25 bitter taste receptors called TAS2Rs. In vitro functional experimental protocol showed that four vitamin compounds were able to activate one or more TAS2R(s). In parallel, we completed this functional experiment with psychometric measurements of the human bitter detection threshold. Comparison of sensory and cellular data revealed the importance of oral physiology and information central integration on the taste stimulus perception. The results obtained demonstrated that the combination of a cellular and sensory approach seemed to be an effective alternative method to evaluate the real contribution of one or more compounds to the negative sensory perceptions of nutritional supplements
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Lay, Russo Nadège. "Différenciation des cellules souches embryonnaires murines et des cellules souches pluripotentes induites humaines en cellules dendritiques : cellules d'intérêt pour les tests de toxicologie." Nice, 2012. http://www.theses.fr/2012NICE4077.
Анотація:
Le septième amendement à la directive cosmétique européenne impose un abandon des tests sur les animaux pour mesurer l’effet allergène ou irritant de certains composés utilisés en cosmétique. La réponse aux allergènes dans le modèle animal regroupe cinq aspects différents, mais dans les tests in vitro chaque aspect est étudié séparément. Parmi les tests de toxicité qui sont envisagés in vitre, les cellules dendritiques (cellules présentatrices de l’antigène) apparaissent come les cellules de choix pour étudier un de ces aspects. Cependant aujourd’hui il est difficile d’obtenir une source fiable et robuste de cellules dendritiques permettant de mettre au point un test réglementaire. Le but de mon projet de thèse a été de proposer un modèle alternatif à ces tests sur les animaux. Pour cela nous avons mis en place les conditions permettant de générer des cellules dendritiques à partir de cellules souches. Pour cela nous disposons de deux sources de cellules souches : les cellules souches embryonnaires murines (mES) et les cellules humaines pluripotentes induites (cellules hiPS). Les hiPS sont des cellules reprogrammées en cellules ayant toutes les caractéristiques des cellules embryonnaires sans que celles-ci ne posent de problèmes éthiques. Ces deux types de cellules souches devaient permettre de disposer d’une source inépuisable et abondante de cellules dendritiques, cellules de choix pour les tests de toxicité in vitro. Nous avons mis au point un protocole permettant de générer et purifier une population de cellules dendritiques à partir de cellules souches embryonnaires de souris. Ces cellules ont été caractérisées par l’expression de marqueurs tels que CD45, CD209, CD86, MHC II, CD14, CD205, CD11c, et par l’étude de marqueurs de surface tels que CD45, CD86. Enfin, nous avons réalisé des tests fonctionnels comme des expériences d’endocytose du dextran-FITC et de réponse de cette population cellulaire à des modèles allergènes de références telles que MCI/MI ou le TNBS. Nous avons ensuite essayé de générer des cellules « dendritiques-like » à partir de cellules iPS humaines en nous basant sur l’expression de marqueurs tels que CD45, CD34, CD1a, CD1c, CD14, CD209, CD207, CD86 et HLA-DR. Plusieurs protocoles ont été envisagés. Toutefois, les cellules « dendritiques-like » obtenues représentent un faible pourcentage des cellules différenciées et le protocole est en cours d’optimisation. De plus en plus de tests utilisent les kératinocytes pour évaluer un autre aspect de la réponse aux allergènes. Nous nous sommes donc intéressés aussi à ces cellules et nous présenterons les premières étapes de différenciation des hiPS qui devraient permettre de générer les kératinocytesThe seventh amendment in the European cosmetic directive imposes an abandonment of the tests on animals to measure the allergenic or irritant effects of some compounds used in cosmetic. The allergenic response in animals ‘models includes five aspects but in the in vitro test each aspect is studied separately. Among the in vitro tests of toxicity which are envisaged, dendritic cells, which are antigen presenting cells, were revealed as cells of choice for study one of these aspects. However today it is difficult to obtain a reliable and strong source of dendritic cells allowing working out a reglementary test. The aim of my thesis project was to propose an alternative model in these tests on animals. For it we set up the conditions allowing generating dendritic cells derived of stern cells. For it we have two sources of stem cells (hiPS) which having all the characteristics of the embryonic stem cells without raise ethical problems. These two types of cells allowed having an inexhaustible and plentiful source of dendritic cells. We set up one protocol allowing generating and purifying a population of dendritic cells from mouse embryonic stem cells. Cells were characterized by gene expression like CD45, CD86. Furthermore we realized as functional test that consists to measure the dextran-FICT endocytosis and the answer of this cellular population to allergenic reference molecules such as MCI/MI or TNBS. We also tried to generate “dendritic-like” cells from human iPS based to expression of specifics markers as CD45, CD34, CD1a, CD14, CD209, CD207, CD86 and HLA-DR. Several protocols were envisaged. However dendritic-like cells obtained represent a low percentage of differentiated cells and the protocol is in the course of optimization. Increasingly tests use keratinocytes cells for evaluate another aspect of allergenic response. So we were interesting also to these cells and we will present first steps differentiation of hiPS that will allow generating keratinocytes
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Santos, Paulo Miguel Trindade. "Estratégias para melhoramento das propriedades mecânicas de compósitos baseados em cortiça aglomerada." Master's thesis, Universidade de Aveiro, 2016. http://hdl.handle.net/10773/22346.
Анотація:
Mestrado em Engenharia MecânicaThe use of cork material has been quickly spreading over the last years due to more care taken to environmental issues. The scrap coming from the production of traditional wine stopper or from the production of other cork products is generally triturated and agglomerated. The so-called agglomerated cork material has been finding a wide range of applications, being a good thermal and acoustic insulator, vibration and impact absorber. Nevertheless, scientific literature has been addressing agglomerated cork in a very general way and defining density and grain size as the two main defining parameters. Many studies that used agglomerated cork, failed to specify the parameters that were used in its production. This dissertation aims to show that, apart from density and grain size, there are other parameters, such as binder type or its quantity, may also have a very significant effect on the mechanical properties of cork in agglomerated form. To this end, the whole production process is detailed and a campaign of static and dynamic tests is carried out. Another goal of this dissertation was to determine the influence of the incorporation of nanomaterials, namely graphene and graphene oxide, as reinforcement on the agglomerated cork. With that goal, a second experimental campaign was planned and carried out. Consisting of quasi-static compression tests and burn tests. With the results obtain it was possible to conclude, that by altering the production parameters of the agglomerated cork it is possible to change its properties, to meet the requirements of the intended application.
Devido a uma maior preocupação ambiental, produtos à base de cortiça têm ganho relevo nas mais diversas áreas. As sobras da produção de rolhas e outros produtos de cortiça são geralmente triturados e aglomerados. O produto resultante é denominado cortiça aglomerada, sendo este um material com grande variedade de aplicações. A cortiça aglomerada é um bom isolante térmico e acústico, tendo ainda boa capacidade de absorver vibrações e energia de impactos. Todavia, a literatura científica tem apresentado a cortiça aglomerada de modo muito genérico e pouco especifico, definindo a densidade e o tamanho do grão utilizado na produção do aglomerado, como os dois principais parâmetros que influenciam as propriedades da cortiça aglomerada. Muitos estudos efetuados, que recorreram a cortiça aglomerada, são vagos nas informações que fornecem sobre o aglomerado de cortiça utilizado, ou mesmo em alguns casos estas informações encontram-se omissas. É o objetivo desta dissertação, demonstrar que existem outros parâmetros que influenciam as propriedades mecânicas da cortiça aglomerada e quantificar a sua influência. Para o efeito, uma campanha experimental com base em testes de compressão quase-estáticos e testes dinâmicos foi planeada e executada. Ainda como objetivo desta dissertação, foi estudar a influência da incorporação de nano materiais, nomeadamente grafeno e óxido de grafeno, como reforço na cortiça aglomerada. Com esse objetivo, uma segunda campanha experimental foi planeada e executada. Com o estudo dos dados obtidos foi possível provar que alterando os parâmetros de produção da cortiça aglomerada, é possível adequar as suas propriedades à aplicação a que destina.
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Coulomb, L'Hermine Aurore. "Rôle physiologique des chimiokines : l'exemple de SDF-1 et de la fractalkine." Paris 11, 1999. http://www.theses.fr/1999PA11T031.
Анотація:
L'expression et le rôle des chimiokines dans l'organisation et le développement du système immunitaire à l'état basal sont très peu connus. Pour aborder cette question, l'expression tissulaire des chimiokines dans différents organes à l'état normal a été étudiée. Tout d'abord, l'expression de la chimiokine SDF-1 au cours du développement embryonnaire et fœtal chez l'homme a été analysée. SDF-1 est exprimé par les cellules du mésoderme de la splahchnopleure intraembryonnaire et par toutes les cellules mésothéliales chez le foetus. Dans les tissus périphériques foetaux, SDF-1 est fortement exprimé par la plupart des cellules épithéliales. Dans le foie fœtal, les hépatocytes n'expriment pas SDF-1 alors qu'il est fortement exprimé par les cellules épithéliales biliaires des plaques ductales et des canaux biliaires intrahépatiques. Les précurseurs B, exprimant VpréB, sont essentiellement localisés autour des espaces portes en contact étroit avec les cellules épithéliales de la plaque ductale. Ces résultats suggèrent que SDF1 est impliqué dans le développement de la lymphopoïèse B précoce chez l 'embryon et que les cellules épithéliales de la plaque ductale jouent pour la lymphopoïèse B du foie fœtal un rôle comparable à celui des cellules épithéliales de la bourse de Fabricius chez les oiseaux pour la lymphopoïèse B, ou à celui des cellules épithéliales thymiques pour la lymphopoïèse T. Nous avons ensuite étudié l'expression de la chimiokine fractalkine dans les tissus périphériques et les organes lymphoïdes des sujets adultes ainsi que l’expression et la fonction de son récepteur CX3CR1 par les différentes populations lymphocytaires T. Nous avons montré que CX3CR1 est exprimé par les cellules CD4+ mémoires activées et qu’il est fonctionnel sur ces cellules. Dans les tissus périphériques, la chimiokine fractalkine est exprimée par les cellules endothéliales. Dans les ganglions, la fractalkine est exprimée par les cellules endothéliales des veinules post-capillaire (HEV), par les cellules dendritiques, par les cellules folliculaires dendritiques et par de lymphocytes des follicules lymphoïdes. Dans le thymus, la fractalkine est exprimée par le cellules endothéliales sous capsulaires. Ces résultats suggèrent que les lymphocytes T CD4+ qui ont été activés dans les zones T, expriment CX3CR1 et migrent sous l'effet de la fractalkine soit dans les tissus périphériques, soit dans les centres germinatifs. Dans ce dernier site, l'interaction entre la fractalkine et son récepteur pourrait favoriser les contacts entre les cellules folliculaires dendritiques, les lymphocytes B et les lymphocytes T activés. Ainsi, il apparaît que certaines chimiokines sont exprimées constitutivement dans de nombreux tissus. Au cours du développement, ces chimiokines peuvent jouer un rôle dans la migration et la maturation de certaines populations cellulaires. Chez l'adulte, ces chimiokines contribuent à la surveillance immunologique exercée par les lymphocytes « sentinelles », et à l'organisation fonctionnelle des tissus lymphoïdes.
9
Stoian, Alina. "Modélisation et simulation de l'atmosphère d'une enceinte membranaire pour des tests de toxicité." Thesis, Montpellier 2, 2012. http://www.theses.fr/2012MON20026.
Анотація:
Un problème fondamental pendant l'évaluation in vitro de la toxicité de composés organiques volatils (COVs) est le manque de connaissance de l'évolution de la concentration des COVs à laquelle les systèmes vivants sont exposés au cours des études expérimentales. Ce travail présente un nouveau dispositif expérimental conçu pour étudier l'exposition des systèmes vivants aux COVs. Le dispositif est formé de deux compartiments séparés par une membrane hydrophobe poreuse et permet des durées relativement longues de manipulations sans restreindre la respiration cellulaire. Une modélisation théorique qui couple la conservation de masse et du moment entre les différentes phases et la respiration des cellules hybridomes (ATCC CRL-1606) au sein du dispositif a été développée. Le modèle permet de prédire l'évolution de la concentration des COVs, de l'oxygène et du dioxyde de carbone dans le dispositif. Les résultats simulés pour le transfert des COVs ont revélé une bonne concordance avec les résultats expérimentaux et ont montré que le type de membrane et son diamètre, le coefficient de partage des COVs et la hauteur de la phase liquide ont une influence significative sur l'évolution de la concentration de ceux-ci dans la phase liquide. Néanmoins la disponibilité de l'oxygène au niveau des cellules dépend principalement de la densité cellulaire initiale, de la vitesse spécifique de consommation de ce gaz et de la hauteur du liquide alors que les paramètres liés à la membrane ont une influence sur le contrôle du pHA major problem during in vitro evaluation of the toxicity of volatile organic compounds (VOC) is the lack of knowledge of the evolution of the concentration of such compounds during the course of experimental studies with living systems. This work presents the design of a novel experimental device for the study of cell culture exposure to VOCs. The device is made of two compartments separated by a porous hydrophobic membrane and allows relatively long durations of handling without restricting cellular breathing. A theoretical modeling which couples mass and moment conservation between the different phases inside the device with the breathing kinetics of hybridoma cells (ATCC CRL-1606) was developed. The model allows predicting the evolution of the concentration of the VOCs, the oxygen and the carbon dioxide inside the device. The simulations of the mass transfer of the VOCs simulated presented a good agreement with experiments and showed that the type of membrane and its diameter, the VOCs partition coefficient and the height of the liquid phase have a significant influence on the evolution of their concentration in the liquid phase. Nevertheless, the availability of oxygen for the cells depends mainly on the initial cellular density, the specific kinetics of consumption of this gas and on the height of the liquid phase, whereas the parameters related to membrane have an influence on the control of the pH
10
Al-Dafafea, Taher. "Analyses expérimentale et numérique du comportement de poutres à ouvertures d'âmes raidies." Thesis, Université Clermont Auvergne (2017-2020), 2018. http://www.theses.fr/2018CLFAC024/document.
Анотація:
La présente thèse vise à caractériser le comportement mécanique à la ruine de poutres métalliques avec ouvertures, de formes et de tailles variables, renforcées ou non par raidisseurs. L’étude s’intéresse à des poutres de dimensions réalistes et s’appuie sur une combinaison de différentes approches : essais, modèles éléments finis et modèles analytiques. Les raidisseurs sont généralement utilisés pour corriger certaines faiblesses au niveau du comportement mécanique autour des ouvertures. Autour des ouvertures rectangulaires, ces raidisseurs, disposés verticalement ou horizontalement, ont fait l’objet de peu d’études scientifiques publiées. Généralement, le comportement des poutres à ouvertures d’âmes est considéré comme étant similaire à celui d’une poutre échelle (ou poutre Vierendeel) chargée aux noeuds. Cette hypothèse permet de considérer que les membrures de l’ouverture sont soumises à un moment fléchissant local bi-triangulaire sur la longueur de l’ouverture. Cependant, la distribution du moment fléchissant, et de ses contraintes axiales, le long d’une membrure peut s’avérer être plus complexe et dépend de la forme de l’ouverture (rectangulaire, hexagonale, circulaire, sinusoïdale ou quelconque), de la position de l’ouverture le long de la poutre et enfin, du type de chargement (concentré ou uniformément réparti). Plusieurs études numériques et expérimentales ont déjà été menées sur les poutres à ouvertures d’âmes et ont permis de développer différentes approches analytiques en vue de décrire leurs comportements. Cependant, ces modèles montrent certaines imprécisions ou insuffisances pour différents types et dimensions d’ouvertures notamment les ouvertures rectangulaires. Les travaux présentés dans cette thèse font le point sur les principaux modèles existants de calcul de résistance des poutres avec ouvertures d’âmes. Ils présentent notamment leurs avantages et limites. Pour conforter les descriptions basées sur les analyses bibliographiques, une campagne expérimentale est réalisée pour valider un modèle éléments finis développé dans le cadre de l’étude. Les essais s’appuient sur des tronçons de poutres de dimensions réalistes avec différentes configurations d’ouvertures isolées renforcées ou non par des raidisseurs. Les mesures autour de l’ouverture utilisent des jauges de déformation pour analyser le profil des contraintes et son évolution, au cours du chargement, dans différentes sections critiques. Les essais sont menés jusqu’à la ruine qui s’est développée généralement par une combinaison de comportement élasto-plastique et d’instabilité locale autour des ouvertures. Certaines ruines se sont produites par rupture en traction-cisaillement de l’acier dans des zones critiques. Les analyses numériques et expérimentales ont permis d’étudier l’influence de différentes conditions sur la distribution des contraintes, notamment axiales, au sein d’une membrure d’ouverture, en vue d’évaluer son potentiel de voilement local qui reste un phénomène complexe à appréhender. Elles ont permis aussi de comprendre le fonctionnement mécanique des ouvertures renforcées par des raidisseurs de différentes dimensions et positions. L’étude paramétrique menée, en utilisant le modèle éléments finis validé par essai, a permis d’évaluer la pertinence des hypothèses retenues dans les approches analytiques existantes. Ces analyses ont permis aussi de proposer un modèle analytique tenant compte du comportement d’ouvertures isolées avec ou sans raidisseursThe present thesis aims to characterize the mechanical behavior to failure of steel beams with openings, with variable shapes and sizes, reinforced or not by stiffeners. The study considers beams of realistic dimensions and combines different approaches: tests, finite element models and analytical models. The stiffeners are generally used to improve some weaknesses in the mechanical behavior around the openings. Around rectangular openings, these stiffeners, in vertical or horizontal arrangements, have been the subject of limited number of scientific publications. In general, the behavior of beams with web openings is considered similar to that of Vierendeel beams with loads applied at the nodes. This hypothesis allows to consider that each frame around the opening is characterized by a bi-triangular local bending moment along the frame elements. In fact, the bending moment distribution, and their resultant axial stresses, along a frame can be more complex and depends on the shape of the opening (rectangular, hexagonal, circular, sinusoidal or any), the position of the opening along the beam and finally, the type of loading (concentrated or uniformly distributed). Several numerical and experimental studies have been conducted on the beams with web openings and different analytical approaches have been developed to describe and predict the behavior of these beams. However, these models show some inaccuracies or inadequacies depending on the types and dimensions of openings including rectangular openings. The work presented in this thesis examines the main existing models predicting the resistance for beams with web openings. It shows their advantages and limits based on the existing but limited results. To obtain additional and specific results to be used in the comparisons and to validate a finite element model developed within the framework of the study, an experimental campaign is carried out. The tests are focused on beams of real dimensions with different configurations of isolated openings reinforced or not by stiffeners. The measurements around the opening use strain gauges to analyze the stress profile and its evolution, during loading, in different critical sections. The tests are carried out until failure generally characterized by a combination of elastic-plastic behavior and local instability around openings. Some final failures occurred by tensile-shear fracture of steel in some critical zones. Numerical and experimental analyzes are performed to study the influence of various conditions on the stresses distributions, in particular axial stresses, within the frames around the openings. The stress distribution is mainly observed to evaluate the local buckling potential that remains a complex phenomenon difficult to predict. The results are also analyzed to understand the mechanical behavior of the openings reinforced by stiffeners of different dimensions and positions. The parametric study conducted using the validated finite element model allows evaluating the relevance of the assumptions considered in the existing analytical approaches. These analyzes made it possible to propose an analytical model taking into-account the behavior of isolated openings with or without stiffeners
Книги з теми "Cellular tests":
1
Stanley, Lesley A. Molecular and cellular toxicology: An introduction. Chichester, West Sussex, UK: John Wiley & Sons Inc., 2014.
2
Kajastila, Riitta. Fire tests on coverings with a substrate of cellular plastics. Espoo: Technical Research Centre of Finland, 1989.
3
International, Conference on Labeled Antibodies (8th 1985 Tokyo Japan). Cellular, molecular, and genetic approaches to immunodiagnosis and immunotherapy. Basel: Karger, 1987.
4
Verhoeven, G., and U. F. Habenicht, eds. Molecular and Cellular Endocrinology of the Testis. Berlin, Heidelberg: Springer Berlin Heidelberg, 1994. http://dx.doi.org/10.1007/978-3-662-22189-1.
5
European Workshop on Molecularand Cellular Endocrinology of the Testis (4th 1986 Capri, Italy). Molecular and cellular endocrinology of the testis: Proceedings of the IV European Workshop on Molecular and Cellular Endocrinology of the Testis, Capri, Italy, 9-12April 1986. Edited by Stefanini Mario 1918-. Amsterdam: Excerpta Medica, 1986.
6
European Workshop on Molecular and Cellular Endocrinology of the Testis. (4th 1986 Capri, Italy). Molecular and cellular endocrinology of the testis: Proceedings of the IV European Workshop on Molecular and Cellular Endocrinology of the Testis, Capri, Italy, 9-12 April 1986. Edited by Stefanini Mario 1916-. Amsterdam: Excerpta Medica, 1986.
7
European Workshop on Molecular and Cellular Endocrinology of the Testis (11th 2000 Saint-Malo, France). Testis, epididymis, and technologies in the year 2000: 11th European Workshop on Molecular and Cellular Endocrinology of the Testis. Edited by Jégou B. 1951-, Pineau C. 1960-, Sáez J. M, and Ernst Schering Research Foundation. Berlin: Springer, 2000.
8
Esposito, Franco. Testa alta, due piedi: Storie di calciomercato : quando non c'erano i procuratori e i cellulari non erano i telefonini. Roma: Absolutely free, 2011.
9
Bain, Barbara J. Blood cells: A practical guide. Philadelphia, Pa: J.B. Lippincott Co., 1989.
10
Bain, Barbara J. Blood cells: A practical guide. 3rd ed. Oxford: Blackwell Science, 2002.
Частини книг з теми "Cellular tests":
1
Abbott, J. G. "Standard Laboratory Tests: How Meaningful are they in Assessing Fire Performance of Insulation Materials?" In Fire and Cellular Polymers, 199–218. Dordrecht: Springer Netherlands, 1986. http://dx.doi.org/10.1007/978-94-009-3443-6_13.
2
Price, Karen. "Cellular Immune Response in Delayed-Type Hypersensitivity Tests." In Immunotoxicology Strategies for Pharmaceutical Safety Assessment, 87–101. Hoboken, NJ, USA: John Wiley & Sons, Inc., 2008. http://dx.doi.org/10.1002/9780470386385.ch8.
3
Tao, X. F., G. K. Schleyer, and Y. Y. Zhao. "Indentation Tests on Al Matrix Syntactic Foams." In IUTAM Symposium on Mechanical Properties of Cellular Materials, 97–104. Dordrecht: Springer Netherlands, 2009. http://dx.doi.org/10.1007/978-1-4020-9404-0_11.
4
McHughen, Alan, Mark Jordan, and Sandra McSheffrey. "Two Years of Transgenic Flax Field Tests: What do They Tell Us?" In Progress in Plant Cellular and Molecular Biology, 207–12. Dordrecht: Springer Netherlands, 1990. http://dx.doi.org/10.1007/978-94-009-2103-0_31.
5
Serra, Roberto, Marco Villani, and Annamaria Colacci. "A cellular automata model for the simulation of in vitro carcinogenesis tests." In Theory and Practical Issues on Cellular Automata, 135–43. London: Springer London, 2001. http://dx.doi.org/10.1007/978-1-4471-0709-5_16.
6
Ezekowitz, Michael D., Edward L. Snyder, Christopher Pope, Patricia Ferri, and Eileen O. Smith. "The use of Indium-111 Platelet Scintigraphy in Man: Comparisions with in Vitro Tests and in Vivo Platelet Function — A Five — Year Experience." In Radiolabeled Cellular Blood Elements, 177–99. Boston, MA: Springer US, 1985. http://dx.doi.org/10.1007/978-1-4684-4922-8_10.
7
Karmakar, Sandip, Debdeep Mukhopadhyay, and Dipanwita Roy Chowdhury. "d-Monomial Tests of Nonlinear Cellular Automata for Cryptographic Design." In Lecture Notes in Computer Science, 261–70. Berlin, Heidelberg: Springer Berlin Heidelberg, 2010. http://dx.doi.org/10.1007/978-3-642-15979-4_28.
8
Sbaytri, Youssef, and Saiida Lazaar. "A Lightweight Cellular Automata-Based Cryptosystem Evaluated with NIST Statistical Tests." In Advances in Intelligent Systems and Computing, 21–29. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-36674-2_3.
9
Roberts, Lee K., and Douglas B. Learn. "Sunscreen SPF Values and Immune Protection Levels Are Equivalent When Tests Are Conducted by Appropriate Methods and Procedures." In Sunscreen Photobiology: Molecular, Cellular and Physiological Aspects, 127–55. Berlin, Heidelberg: Springer Berlin Heidelberg, 1997. http://dx.doi.org/10.1007/978-3-662-10135-3_8.
10
Galindo-Serrano, Ana, Berna Sayrac, Sana Ben Jemaa, Janne Riihijärvi, and Petri Mähönen. "Cellular Coverage Optimization: A Radio Environment Map for Minimization of Drive Tests." In Cognitive Communication and Cooperative HetNet Coexistence, 211–36. Cham: Springer International Publishing, 2014. http://dx.doi.org/10.1007/978-3-319-01402-9_10.
Тези доповідей конференцій з теми "Cellular tests":
1
Hassan, Mohd R., F. Scarpa, N. A. Mohammed, and Y. Ancrenaz. "Conventional and Auxetic SMA Cellular Structures." In ASME 2005 International Mechanical Engineering Congress and Exposition. ASMEDC, 2005. http://dx.doi.org/10.1115/imece2005-81075.
Анотація:
This work illustrates the manufacturing and tensile testing of a novel concept of honeycomb structures with hexagonal and auxetic (negative Poisson’s ratio) topology, made of shape memory alloy (SMA) core material. The honeycombs are manufactured using Nitinol ribbons having 6.40 mm of width and 0.2 mm of thickness. The ribbons were inserted in a special dye using cyanoacrilate to bond the longitudinal strips of the unit cells. The ribbons were subjected to tensile test at room temperature (martensite finish) and austenite finish temperature. Tensile tests at room temperature were performed on the honeycomb. The stress-strain curve obtained from the test on a single ribbon at room temperature was then used to develop nonlinear Finite Element beam elements using a commercial code. The beam elements were then used to model the honeycomb samples under tensile loading. Good agreement is observed between numerical nonlinear simulations and the experimental results.
2
Kishimoto, Satoshi, Kimiyoshi Naito, Toru Shimizu, and Fuxing Yin. "Mechanical Properties of Closed Cellular Materials Containing Polymer." In ASME 2009 Conference on Smart Materials, Adaptive Structures and Intelligent Systems. ASMEDC, 2009. http://dx.doi.org/10.1115/smasis2009-1273.
Анотація:
Cellular materials have unique thermal, acoustic, damping and energy absorbing properties that can be combined with their structural efficiency. Therefore, many kinds of cellular materials have been developed and tested as energy absorbing and damping materials. Particularly, closed cellular materials are thought to have many favorable properties and applications. In this study, a metallic closed cellular materials containing polymer was fabricated by the penetrating polymer into metal foam. The aluminum and stainless steel foams were selected for the metal foam and epoxy resin and polyurethane resin were selected for the penetrated polymer. The mechanical and damping properties of this material were measured. The results of the compressive tests show that this material has different stress-strain curves among the specimens that include different materials in the cells. Also, These results show that this material has high-energy absorption. The internal friction of this material was measured and the result shows that the internal friction of this material is larger than that of pure aluminum closed cellular material without any polymer and change with increasing of temperature.
3
Kishimoto, Satoshi, Kimiyoshi Naito, Toru Shimizu, and Fuxing Yin. "Mechanical Properties of Metallic Cellular Materials With Polymer." In ASME 2010 Conference on Smart Materials, Adaptive Structures and Intelligent Systems. ASMEDC, 2010. http://dx.doi.org/10.1115/smasis2010-3725.
Анотація:
A metallic cellular materials containing polymer was fabricated by the penetrating polymer into metal foam. The aluminum and stainless steel foams were selected for the metal foam and epoxy resin and polyurethane resin were selected for the penetrated polymer. The mechanical, damping shock absorbing properties of this material were measured. The results of the compressive tests show that this material has different stress-strain curves among the specimens that include different materials in the cells. Also, these results show that this material has high-energy absorption. The internal friction of this material was measured and the result shows that the internal friction of this material is larger than that of pure aluminum closed cellular material without any polymer and change with increasing of temperature. The shock absorbability of this material is larger than that of polymer and smaller than that of metallic cellular material.
4
Plourde, B. D., J. P. Abraham, G. S. Mowry, and W. J. Minkowycz. "Wind-Tunnel Tests of Vertical-Axis Wind Turbine Blades." In ASME 2011 5th International Conference on Energy Sustainability. ASMEDC, 2011. http://dx.doi.org/10.1115/es2011-54604.
Анотація:
An ongoing research project is investigating the potential of locating vertical-axis wind turbines (WT) on remote, off-grid cellular communication towers. The goal of the WT is to provide local power generation to meet the electrical needs of the tower. While vertical-axis devices are less efficient than their more traditional horizontal-axis counterparts, they provide a number of practical advantages which make them a suitable choice for the present situation. First, the direction of their axis is aligned with the existing tower and its rotation does not interfere with the tower structure. Second, vertical-axis devices are much less susceptible to the direction of wind and they do not require control-systems to ensure they are oriented correctly. Third, vertical-axis turbines have very low start-up wind speeds so that they generate power over a wide range of speeds. Fourth, since vertical-axis turbines rotate at a slower speed compared with horizontal counterparts, they impart a lessened vibration load to the tower. These facts, collectively, make the vertical-axis turbine suitable for the proposed application. The design process involved a detailed initial design of the turbine blade using computational methods. Next, a trio of designs was evaluated experimentally in a large, low-speed wind tunnel. The wind tunnel is operated by the University of Minnesota’s St. Anthony Falls Fluid Laboratory. The tunnel possesses two testing sections. The larger section was sufficient to test a full-size turbine blade. Accounting was taken of the blockage effect following the tests. The experiments were completed on (1) a solid-wing design (unvented), (2) a slotted-wing design (vented), and (3) a capped-and-slotted design (capped). Conditions spanned a wide range of wind speeds (4.5–11.5 m/s). The turbines were connected to electronics which simulated a range of electrical loads. The tested range was selected to span the expected range of resistances which will be found in practice. It was discovered that over a range of these wind speeds and electrical resistances, slots located on the wings result in a slight improvement in power generation. On the other hand, the slotted-and-capped design provided very large increases in performance (approximately 200–300% compared with the unvented version). This large improvement has justified commercialization of the product for use in powering remote, off-grid cellular communication towers.
5
Uddin, Md Salah, Jaehyung Ju, and Nandika D’Souza. "An Experimental Study on the Mode I Fracture Behavior of Hexagonal Honeycombs." In ASME 2013 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/imece2013-64914.
Анотація:
Cellular materials have a high strength-to-weight ratio, which is good for lightweight structural applications. In order to accelerate the commercial use of cellular materials in the structural applications, a well understanding of fracture behavior of cellular materials is required in terms of structural integrity. The objective of the study is to develop a predictive model on fracture behavior of orthotropic cellular polymers, prepared from an additive manufacturing method, under the mode-I macroscopic loading. The constituent material’s fracture properties are obtained from the three-point bending test of samples with a notched crack. Using the base material’s properties, a model on fracture toughness of hexagonal honeycombs with a varying cell angle is developed using a linear elastic fracture mechanics (LEFM) model of a cell wall material. Numerical and experimental tests will follow to validate the model.
6
Casas, Pedro, Martin Varela, Pierdomenico Fiadino, Mirko Schiavone, Helena Rivas, and Raimund Schatz. "On the analysis of QoE in cellular networks: From subjective tests to large-scale traffic measurements." In 2015 International Wireless Communications and Mobile Computing Conference (IWCMC). IEEE, 2015. http://dx.doi.org/10.1109/iwcmc.2015.7289054.
7
Wang, Jun, and Rahul Rai. "Classification of Bio-Inspired Periodic Cubic Cellular Materials Based on Compressive Deformation Behaviors of 3D Printed Parts and FE Simulations." In ASME 2016 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/detc2016-59729.
Анотація:
Bio-inspired materials have shown to have outstanding mechanical properties over man-made materials and are becoming of increasing interest in many fields of practical applications. Additionally, recent advances in materials and fabrication technologies allow for the design and fabrication of micro- and nano-scale structures to serve as cellular units in macro-scale materials. The mechanical behaviors of cellular solids, including stiffness and strength, can be tuned by simply tailoring the underlying geometry of the structure. In this paper the answer to the following research question is investigated: Can seemingly different bio-inspired geometries of cellular solids result in similar mechanical behaviors? Specifically, the effects of geometry on the compressive deformation responses of multiple bio-inspired periodic cubic cellular structures at macro scale are investigated both through physical tests and FE simulations of 3D printed specimens. The paper outlines standardization of specimens and tests for such a study. Additionally, a $1 recognizer based classification process is used on curves representing compressive deformation behaviors of different bio-inspired geometries to cluster them into same group.
8
Abraham, John, Brian Plourde, Greg Mowry, and Ephraim Sparrow. "Experimental Test of Multi-Stage Vertical-Axis Turbines for Cellular Communication Applications." In ASME 2012 6th International Conference on Energy Sustainability collocated with the ASME 2012 10th International Conference on Fuel Cell Science, Engineering and Technology. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/es2012-91025.
Анотація:
A multi-year research program has generated a working prototype for a vertical-axis wind turbine that is capable of powering cellular communication equipment. The turbine is designed to be affixed to already existing communication towers and thereby has a reduced cost of installation. The turbine is driven by air drag forces rather than by lift. It has a number of novel features including venting slots that are created to reduce the thrust loading on the communication tower. In addition, contoured caps are affixed to the upper and lower edges of the turbine blades to increase power production. As previously mentioned, the turbine design itself is a drag-based concept rather than the more typical lift-driven devices. The advantages of the drag-based design are: 1. lower startup wind speed, 2. slower rotation and a lessened vibrational load on the tower, 3. less sensitive to wind direction, and 4. it can be aligned with the tower. The design of the device was carried out through a combination of numerical simulation and experimentation. The simulations have evolved from preliminary two-dimensional calculations to a fully three dimensional, unsteady, computational fluid dynamic analysis. Simultaneously, the experiments have included both in-field and wind-tunnel tests of various stages of the turbine design. An outcome of the effort is a third-generation working vertical-axis wind turbine (VAWT) that is currently being evaluated with in-field tests. The results of the tests are positive and confirm the expectations that were developed during the product design phase. The turbine, which can be constructed with various rotor stages, has the capability of producing approximately 2–3 kW of power in wind-speed environments of 12–16 m/s. These power production levels are greatly in excess of that required to fully power the electronics equipment on a typical cellular communication tower. Unfortunately, subsequent tests showed that the turbine production dropped approximately sevenfold. The cause of the decrease in performance was friction in the mechanical components which coupled the rotating shaft to the support structure. This recognition reinforces the importance of low-resistance mechanical design for VAWTs. Another aspect of the turbine design is the specialized electronics which allow the electronics to adapt to local wind speeds and consequently increase the efficiency of the power production.
9
Hinnerichs, Terry, William Scherzinger, Mike Nielsen, Tom Carne, Eric Stasiunas, and Wei-Yang Lu. "Validation of a New Aluminum Honeycomb Crush Model With Dynamic Impact Tests." In ASME 2007 International Mechanical Engineering Congress and Exposition. ASMEDC, 2007. http://dx.doi.org/10.1115/imece2007-41905.
Анотація:
This paper describes a process for validating a new constitutive model for large, high strain-rate deformation of aluminum honeycomb, called the Honeycomb Crush Model (HCM). This model has 6 yield surfaces that are coupled to account for the orthotropic behavior of the cellular honeycomb being crushed on-axis and off-axis. The HCM has been implemented in the transient dynamic Presto finite element code for dynamic impact simulations. The HCM constitutive parameters were identified based on Presto finite element models that were used to simulate uniaxial and biaxial crush tests of 38 lb/ft3 aluminum honeycomb and reported in an earlier paper. This paper focuses on validating the HCM in the Presto code for application to impact situations that have honeycomb crush velocities up to 85 ft/sec. Also, a new approach for incorporating rate sensitivity into the model is described. A two-stage energy absorber with integrated aluminum honeycomb is described as the configuration for dynamic impact validation experiments. The test parameters and finite element model will be described along with the uncertainty quantification that was done and propagated through the model. Finally, correlation of model predictions and test results will be presented using an energy based validation metric.
10
Hinnerichs, Terry, Michael Neilsen, and Wei-Yang Lu. "A New Aluminum Honeycomb Constitutive Model for Impact Analyses." In ASME 2004 International Mechanical Engineering Congress and Exposition. ASMEDC, 2004. http://dx.doi.org/10.1115/imece2004-60751.
Анотація:
A new constitutive model for large deformation of aluminum honeycomb has been developed. This model has six yield surfaces that are coupled to account for the orthotropic behavior of the cellular honeycomb being crushed on-axis and off-axis. Model parameters have been identified to fit uniaxial and biaxial crush test data for high density (38 lb/ft3) aluminum honeycomb. The honeycomb model was implemented in the transient dynamic Presto finite element code for dynamic impact simulations. In order to extract useful constitutive-parameter information from crush tests, each test configuration and process is simulated with a Presto finite element model to analyze the non-uniform strain/crush behavior within the test samples. Results from the suite of honeycomb crush tests that were used to calibrate the new honeycomb model are shown. Also, the honeycomb model’s predictions are compared with test data and with the older Orthotropic Crush Model predictions.
Звіти організацій з теми "Cellular tests":
1
Krogmeier, J., and Darcy Bullock. Statewide Wireless Communications Project, Volume 1: Communication Field Tests for Satellite, Cellular, and Spread Spectrum Radio. West Lafayette, IN: Purdue University, 2008. http://dx.doi.org/10.5703/1288284314218.
2
Bercovier, Herve, Raul Barletta, and Shlomo Sela. Characterization and Immunogenicity of Mycobacterium paratuberculosis Secreted and Cellular Proteins. United States Department of Agriculture, January 1996. http://dx.doi.org/10.32747/1996.7573078.bard.
Анотація:
Our long-term goal is to develop an efficient acellular vaccine against paratuberculosis based on protein antigen(s). A prerequisite to achieve this goal is to analyze and characterize Mycobacterium paratuberculosis (Mpt) secreted and cellular proteins eliciting a protective immune response. In the context of this general objective, we proposed to identify, clone, produce, and characterize: the Mpt 85B antigen and other Mpt immunoreactive secreted proteins, the Mpt L7/L12 ribosomal protein and other immunoreactive cellular proteins, Mpt protein determinants involved in invasion of epithelial cells, and Mpt protein antigens specifically expressed in macrophages. Paratuberculosis is still a very serious problem in Israel and in the USA. In the USA, a recent survey evaluated that 21.6% of the dairy herd were infected with Mpt resulting in 200-250 million dollars in annual losses. Very little is known on the virulence factors and on protective antigens of Mpt. At present, the only means of controlling this disease are culling or vaccination. The current vaccines do not allow a clear differentiation between infected and vaccinated animals. Our long-term goal is to develop an efficient acellular paratuberculosis vaccine based on Mpt protein antigen(s) compatible with diagnostic tests. To achieve this goal it is necessary to analyze and characterize secreted and cellular proteins candidate for such a vaccine. Representative Mpt libraries (shuttle plasmid and phage) were constructed and used to study Mpt genes and gene products described below and will be made available to other research groups. In addition, two approaches were performed which did not yield the expected results. Mav or Mpt DNA genes that confer upon Msg or E. coli the ability to invade and/or survive within HEp-2 cells were not identified. Likewise, we were unable to characterize the 34-39 kDa induced secreted proteins induced by stress factors due to technical difficulties inherent to the complexity of the media needed to support substantial M. pt growth. We identified, isolated, sequenced five Mpt proteins and expressed four of them as recombinant proteins that allowed the study of their immunological properties in sensitized mice. The AphC protein, found to be up regulated by low iron environment, and the SOD protein are both involved in protecting mycobacteria against damage and killing by reactive oxygen (Sod) and nitrogen (AhpC) intermediates, the main bactericidal mechanisms of phagocytic cells. SOD and L7/L12 ribosomal proteins are structural proteins constitutively expressed. 85B and CFP20 are both secreted proteins. SOD, L7/L12, 85B and CFP20 were shown to induce a Th1 response in immunized mice whereas AphC was shown by others to have a similar activity. These proteins did not interfere with the DTH reaction of naturally infected cows. Cellular immunity provides protection in mycobacterial infections, therefore molecules inducing cellular immunity and preferentially a Th1 pathway will be the best candidate for the development of an acellular vaccine. The proteins characterized in this grant that induce a cell-mediated immunity and seem compatible with diagnostic tests, are good candidates for the construction of a future acellular vaccine.
3
Eldar, Avigdor, and Donald L. Evans. Streptococcus iniae Infections in Trout and Tilapia: Host-Pathogen Interactions, the Immune Response Toward the Pathogen and Vaccine Formulation. United States Department of Agriculture, December 2000. http://dx.doi.org/10.32747/2000.7575286.bard.
Анотація:
In Israel and in the U.S., Streptococcus iniae is responsible for considerable losses in various fish species. Poor understanding of its virulence factors and limited know-how-to of vaccine formulation and administration are the main reasons for the limited efficacy of vaccines. Our strategy was that in order to Improve control measures, both aspects should be equally addressed. Our proposal included the following objectives: (i) construction of host-pathogen interaction models; (ii) characterization of virulence factors and immunodominant antigens, with assessment of their relative importance in terms of protection and (iii) genetic identification of virulence factors and genes, with evaluation of the protective effect of recombinant proteins. We have shown that two different serotypes are involved. Their capsular polysaccharides (CPS) were characterized, and proved to play an important role in immune evasion and in other consequences of the infection. This is an innovative finding in fish bacteriology and resembles what, in other fields, has become apparent in the recent years: S. iniae alters surface antigens. By so doing, the pathogen escapes immune destruction. Immunological assays (agar-gel immunodiffusion and antibody titers) confirmed that only limited cross recognition between the two types occurs and that capsular polysaccharides are immunodominant. Vaccination with purified CPS (as an acellular vaccine) results in protection. In vitro and ex-vivo models have allowed us to unravel additional insights of the host-pathogen interactions. S. iniae 173 (type II) produced DNA fragmentation of TMB-8 cells characteristic of cellular necrosis; the same isolate also prevented the development of apoptosis in NCC. This was determined by finding reduced expression of phosphotidylserine (PS) on the outer membrane leaflet of NCC. NCC treated with this isolate had very high levels of cellular necrosis compared to all other isolates. This cellular pathology was confirmed by observing reduced DNA laddering in these same treated cells. Transmission EM also showed characteristic necrotic cellular changes in treated cells. To determine if the (in vitro) PCD/apoptosis protective effects of #173 correlated with any in vivo activity, tilapia were injected IV with #173 and #164 (an Israeli type I strain). Following injection, purified NCC were tested (in vitro) for cytotoxicity against HL-60 target cells. Four significant observations were made : (i) fish injected with #173 had 100-400% increased cytotoxicity compared to #164 (ii) in vivo activation occurred within 5 minutes of injection; (iii) activation occurred only within the peripheral blood compartment; and (iv) the isolate that protected NCC from apoptosis in vitro caused in vivo activation of cytotoxicity. The levels of in vivo cytotoxicity responses are associated with certain pathogens (pathogen associated molecular patterns/PAMP) and with the tissue of origin of NCC. NCC from different tissue (i.e. PBL, anterior kidney, spleen) exist in different states of differentiation. Random amplified polymorphic DNA (RAPD) analysis revealed the "adaptation" of the bacterium to the vaccinated environment, suggesting a "Darwinian-like" evolution of any bacterium. Due to the selective pressure which has occurred in the vaccinated environment, type II strains, able to evade the protective response elicited by the vaccine, have evolved from type I strains. The increased virulence through the appropriation of a novel antigenic composition conforms with pathogenic mechanisms described for other streptococci. Vaccine efficacy was improved: water-in-oil formulations were found effective in inducing protection that lasted for a period of (at least) 6 months. Protection was evaluated by functional tests - the protective effect, and immunological parameters - elicitation of T- and B-cells proliferation. Vaccinated fish were found to be resistant to the disease for (at least) six months; protection was accompanied by activation of the cellular and the humoral branches.
4
Johra, Hicham. Project CleanTechBlock 2 Thermal conductivity measurement of cellular glass samples. Department of the Built Environment, Aalborg University, January 2019. http://dx.doi.org/10.54337/aau307323438.
Анотація:
The goal of the project CleanTechBlock 2 is to develop and test a durable and sustainable construction wall element which complies with the building regulations of 2020, and has a certain aesthetics attractiveness. The CleanTechBlock (CTB) prefabricated elements consist of cellular glass insulation blocks mounted in between two layers of brick masonry [1] [2]. The aim of this technical document is to report the results of the different experimental investigations performed on the CTB and other commercial cellular glass samples to determined their thermal conductivity. These experimental investigations have been carried out at the Laboratory of Building Energy and Indoor Environment at the Department of Civil Engineering of Aalborg University (Denmark).
5
Martinho, Diogo, Hugo Sarmento, Ana Faria, Hadi Nobari, and Adam Field. Oral branched chain amino acids supplementation in trained participants: a systematic review. INPLASY - International Platform of Registered Systematic Review and Meta-analysis Protocols, April 2022. http://dx.doi.org/10.37766/inplasy2022.4.0014.
Анотація:
Review question / Objective: The present review following PICO criteria: (1) population – athletes or participants described with experience in sport; (2) intervention – oral branched chain amino acids (BCAAs) supplementation; (3) outcomes – indicators of performance, body composition, recovery, hormonal response or cellular signalling; (4) comparator – control group or placebo, and; (5) output – pre-and post-test changes. Exclusion criteria were: (1) studies that described participants as healthy or active; (2) articles classified as letter to editor or review, and; (3) BCAAs supplementation by infusion or combined with other substances. Condition being studied: The condition to be studied is the ingestion of branched chain amino acids in participants with training experience (participants involved in organized sports or with training experience). Note, the participants classified as active or healthy were not included in this review.
6
Hansen, Peter J., and Amir Arav. Embryo transfer as a tool for improving fertility of heat-stressed dairy cattle. United States Department of Agriculture, September 2007. http://dx.doi.org/10.32747/2007.7587730.bard.
Анотація:
The overall objective of the current proposal is to develop procedures to improve the pregnancy rate achieved following transfer of fresh or cryopreserved embryos produced in the laboratory into heat-stress recipients. The overall hypothesis is that pregnancy rate in heat-stressed lactating cows can be improved by use of embryo transfer and that additional gains in pregnancy rate can be achieved through development of procedures to cryopreserve embryos, select embryos most likely to establish and maintain pregnancy after transfer, and to enhance embryo competence for post-transfer survival through manipulation of culture conditions. The original specific objectives were to 1) optimize procedures for cryopreservation (Israel/US), 2) develop procedures for identifying embryos with the greatest potential for development and survival using the remote monitoring system called EmbryoGuard (Israel), 3) perform field trials to test the efficacy of cryopreservation and the EmbryoGuard selection system for improving pregnancy rates in heat-stressed, lactating cows (US/Israel), 4) test whether selection of fresh or frozen-thawed blastocysts based on measurement of group II caspase activity is an effective means of increasing survival after cryopreservation and post-transfer pregnancy rate (US), and 5) identify genes in blastocysts induced by insulin-like growth factor-1 (IGF-1) (US). In addition to these objectives, additional work was carried out to determine additional cellular determinants of embryonic resistance to heat shock. There were several major achievements. Results of one experiment indicated that survival of embryos to freezing could be improved by treating embryos with cytochalasin B to disrupt the cytoskeleton. An additional improvement in the efficacy of embryo transfer for achieving pregnancy in heat-stressed cows follows from the finding that IGF-1 can improve post-transfer survival of in vitro produced embryos in the summer but not winter. Expression of several genes in the blastocyst was regulated by IGF-1 including IGF binding protein-3, desmocollin II, Na/K ATPase, Bax, heat shock protein 70 and IGF-1 receptor. These genes are likely candidates 1) for developing assays for selection of embryos for transfer and 2) as marker genes for improving culture conditions for embryo production. The fact that IGF-1 improved survival of embryos in heat-stressed recipients only is consistent with the hypothesis that IGF-1 confers cellular thermotolerance to bovine embryos. Other experiments confirmed this action of IGF-1. One action of IGF-1, the ability to block heat-shock induced apoptosis, was shown to be mediated through activation of the phosphatidylinositol 3-kinase pathway. Other cellular determinants of resistance of embryos to elevated temperature were identified including redox status of the embryo and the ceramide signaling pathway. Developmental changes in embryonic apoptosis responses in response to heat shock were described and found to include alterations in the capacity of the embryo to undergo caspase-9 and caspase-3 activation as well as events downstream from caspase-3 activation. With the exception of IGF-1, other possible treatments to improve pregnancy rate to embryo transfer were not effective including selection of embryos for caspase activity, treatment of recipients with GnRH.and bilateral transfer of twin embryos. In conclusion, accomplishments achieved during the grant period have resulted in methods for improving post-transfer survival of in vitro produced embryos transferred into heat-stressed cows and have lead to additional avenues for research to increase embryo resistance to elevated temperature and improve survival to cryopreservation. In addition, embryo transfer of vitrified IVF embryos increased significantly the pregnancy rate in repeated breeder cows.
7
Lapidot, Moshe, and Vitaly Citovsky. molecular mechanism for the Tomato yellow leaf curl virus resistance at the ty-5 locus. United States Department of Agriculture, January 2016. http://dx.doi.org/10.32747/2016.7604274.bard.
Анотація:
Tomato yellow leaf curl virus (TYLCV) is a major pathogen of tomato that causes extensive crop loss worldwide, including the US and Israel. Genetic resistance in the host plant is considered highly effective in the defense against viral infection in the field. Thus, the best way to reduce yield losses due to TYLCV is by breeding tomatoes resistant or tolerant to the virus. To date, only six major TYLCV-resistance loci, termed Ty-1 to Ty-6, have been characterized and mapped to the tomato genome. Among tomato TYLCV-resistant lines containing these loci, we have identified a major recessive quantitative trait locus (QTL) that was mapped to chromosome 4 and designated ty-5. Recently, we identified the gene responsible for the TYLCV resistance at the ty-5 locus as the tomato homolog of the gene encoding messenger RNA surveillance factor Pelota (Pelo). A single amino acid change in the protein is responsible for the resistant phenotype. Pelo is known to participate in the ribosome-recycling phase of protein biosynthesis. Our hypothesis was that the resistant allele of Pelo is a “loss-of-function” mutant, and inhibits or slows-down ribosome recycling. This will negatively affect viral (as well as host-plant) protein synthesis, which may result in slower infection progression. Hence we have proposed the following research objectives: Aim 1: The effect of Pelota on translation of TYLCV proteins: The goal of this objective is to test the effect Pelota may or may not have upon translation of TYLCV proteins following infection of a resistant host. Aim 2: Identify and characterize Pelota cellular localization and interaction with TYLCV proteins: The goal of this objective is to characterize the cellular localization of both Pelota alleles, the TYLCV-resistant and the susceptible allele, to see whether this localization changes following TYLCV infection, and to find out which TYLCV protein interacts with Pelota. Our results demonstrate that upon TYLCV-infection the resistant allele of pelota has a negative effect on viral replication and RNA transcription. It is also shown that pelota interacts with the viral C1 protein, which is the only viral protein essential for TYLCV replication. Following subcellular localization of C1 and Pelota it was found that both protein localize to the same subcellular compartments. This research is innovative and potentially transformative because the role of Peloin plant virus resistance is novel, and understanding its mechanism will lay the foundation for designing new antiviral protection strategies that target translation of viral proteins. BARD Report - Project 4953 Page 2
8
Hansen, Peter J., Zvi Roth, and Jeremy J. Block. Improving oocyte competence in dairy cows exposed to heat stress. United States Department of Agriculture, January 2014. http://dx.doi.org/10.32747/2014.7598163.bard.
Анотація:
Original Objectives. The overall goal is to develop methods to increase pregnancy rate in lactating dairy cows exposed to heat stress through methods that minimize damage to the oocyte and embryo caused by heat stress. Objectives were as follows: (1) examine the protective effects of melatonin on developmental competence of oocytes exposed to elevated temperature in vitro; (2) test whether melatonin feeding can improve developmental competence of oocytes in vivo and, if so, whether effects are limited to the summer or also occur in the absence of heat stress; and (3) evaluate the effectiveness of improving fertility by facilitating follicular turnover in the summer and winter. Revised Objectives. (1) Examine protective effects of melatonin and follicular fluid on developmental competence of oocytes exposed to elevated temperature in vitro; (2) examine the protective effects of melatonin on developmental competence of embryos exposed to elevated temperature in vitro; (3) evaluate effectiveness of improving fertility by administering human chorionicgonadotropin (hCG) to increase circulating concentrations of progesterone and evaluate whether response to hCG depends upon genotype for four mutations reported to be related to cow fertility; and (4) identify genes with allelic variants that increase resistance of embryos to heat shock. Background. The overall hypothesis is that pregnancy success is reduced by heat stress because of damage to the oocyte and cleavage-stage embryo mediated by reactive oxygen species (ROS), and that fertility can be improved by provision of antioxidants or by removing follicles containing oocytes damaged by heat stress. During the study, additional evidence from the literature indicated the potential importance of treatment with chorionicgonadotropin to increase fertility of heat- stressed cows and results from other studies in our laboratories implicated genotype as an important determinant of cow fertility. Thus, the project was expanded to evaluate hCG treatment and to identify whether fertility response to hCG depended upon single nucleotide polymorphisms (SNP) in genes implicated as important for cow fertility. We also evaluated whether a SNP in a gene important for cellular resistance to heat stress (HSPA1L, a member of the heat shock protein 70 family) is important for embryonic resistance to elevated temperature. Major conclusions, solutions & achievements. Results confirmed that elevated temperature increases ROS production by the oocyte and embryo and that melatonin decreases ROS. Melatonin reduced, but did not completely block, damaging effects of heat shock on the oocyte and had no effect on development of the embryo. Melatonin was protective to the oocyte at 0.1-1 μM, a concentration too high to be achieved in cows. It was concluded that melatonin is unlikely to be a useful molecule for increasing fertility of heat-stressed cows. Treatment with hCG at day 5 after breeding increased first-service pregnancy rate for primiparous cows but not for multiparous cows. Thus, hCG could be useful for increasing fertility in first-parity cows. The effectiveness of hCG depended upon genotype for a SNP in COQ9, a gene encoding for a mitochondrial-function protein. This result points the way to future efforts to use genetic information to identify populations of cows for which hormone treatments will be effective or ineffective. The SNP in HSPA1L was related to embryonic survival after heat shock. Perhaps, genetic selection for mutations that increase cellular resistance to heat shock could be employed to reduce effects of heat stress on fertility. Implications, both scientific and agricultural. This project has resulted in abandonment of one possible approach to improve fertility of the heat-stressed cow (melatonin therapy) while also leading to a method for improving fertility of primiparous cows exposed to heat stress (hCG treatment) that can be implemented on farms today. Genetic studies have pointed the way to using genetic information to 1) tailor hormonal treatments to cow populations likely to respond favorably and 2) select animals whose embryos have superior resistance to elevated body temperatures.
9
Epel, Bernard, and Roger Beachy. Mechanisms of intra- and intercellular targeting and movement of tobacco mosaic virus. United States Department of Agriculture, November 2005. http://dx.doi.org/10.32747/2005.7695874.bard.
Анотація:
To cause disease, plant viruses must replicate and spread locally and systemically within the host. Cell-to-cell virus spread is mediated by virus-encoded movement proteins (MPs), which modify the structure and function of plasmodesmata (Pd), trans-wall co-axial membranous tunnels that interconnect the cytoplasm of neighboring cells. Tobacco mosaic virus (TMV) employ a single MP for cell- cell spread and for which CP is not required. The PIs, Beachy (USA) and Epel (Israel) and co-workers, developed new tools and approaches for study of the mechanism of spread of TMV that lead to a partial identification and molecular characterization of the cellular machinery involved in the trafficking process. Original research objectives: Based on our data and those of others, we proposed a working model of plant viral spread. Our model stated that MPᵀᴹⱽ, an integral ER membrane protein with its C-terminus exposed to the cytoplasm (Reichel and Beachy, 1998), alters the Pd SEL, causes the Pd cytoplasmic annulus to dilate (Wolf et al., 1989), allowing ER to glide through Pd and that this gliding is cytoskeleton mediated. The model claimed that in absence of MP, the ER in Pd (the desmotubule) is stationary, i.e. does not move through the Pd. Based on this model we designed a series of experiments to test the following questions: -Does MP potentiate ER movement through the Pd? - In the presence of MP, is there communication between adjacent cells via ER lumen? -Does MP potentiate the movement of cytoskeletal elements cell to cell? -Is MP required for cell-to-cell movement of ER membranes between cells in sink tissue? -Is the binding in situ of MP to RNA specific to vRNA sequences or is it nonspecific as measured in vitro? And if specific: -What sequences of RNA are involved in binding to MP? And finally, what host proteins are associated with MP during intracellular targeting to various subcellular targets and what if any post-translational modifications occur to MP, other than phosphorylation (Kawakami et al., 1999)? Major conclusions, solutions and achievements. A new quantitative tool was developed to measure the "coefficient of conductivity" of Pd to cytoplasmic soluble proteins. Employing this tool, we measured changes in Pd conductivity in epidermal cells of sink and source leaves of wild-type and transgenic Nicotiana benthamiana (N. benthamiana) plants expressing MPᵀᴹⱽ incubated both in dark and light and at 16 and 25 ᵒC (Liarzi and Epel, 2005 (appendix 1). To test our model we measured the effect of the presence of MP on cell-to-cell spread of a cytoplasmic fluorescent probe, of two ER intrinsic membrane protein-probes and two ER lumen protein-probes fused to GFP. The effect of a mutant virus that is incapable of cell-to-cell spread on the spread of these probes was also determined. Our data shows that MP reduces SEL for cytoplasmic molecules, dilates the desmotubule allowing cell-cell diffusion of proteins via the desmotubule lumen and reduces the rate of spread of the ER membrane probes. Replicase was shown to enhance cell-cell spread. The data are not in support of the proposed model and have led us to propose a new model for virus cell-cell spread: this model proposes that MP, an integral ER membrane protein, forms a MP:vRNAER complex and that this ER-membrane complex diffuses in the lipid milieu of the ER into the desmotubule (the ER within the Pd), and spreads cell to cell by simple diffusion in the ER/desmotubule membrane; the driving force for spread is the chemical potential gradient between an infected cell and contingent non-infected neighbors. Our data also suggests that the virus replicase has a function in altering the Pd conductivity. Transgenic plant lines that express the MP gene of the Cg tobamovirus fused to YFP under the control the ecdysone receptor and methoxyfenocide ligand were generated by the Beachy group and the expression pattern and the timing and targeting patterns were determined. A vector expressing this MPs was also developed for use by the Epel lab . The transgenic lines are being used to identify and isolate host genes that are required for cell-to-cell movement of TMV/tobamoviruses. This line is now being grown and to be employed in proteomic studies which will commence November 2005. T-DNA insertion mutagenesis is being developed to identify and isolate host genes required for cell-to-cell movement of TMV.
10
Manulis, Shulamit, Christine D. Smart, Isaac Barash, Guido Sessa, and Harvey C. Hoch. Molecular Interactions of Clavibacter michiganensis subsp. michiganensis with Tomato. United States Department of Agriculture, January 2011. http://dx.doi.org/10.32747/2011.7697113.bard.
Анотація:
Clavibacter michiganensis subsp. michiganensis (Cmm), the causal agent of bacterial wilt and canker of tomato, is the most destructive bacterial disease of tomato causing substantial economic losses in Israel, the U.S.A. and worldwide. The molecular strategies that allow Cmm, a Gram-positive bacterium, to develop a successful infection in tomato plants are largely unknown. The goal of the project was to elucidate the molecular interactions between Cmmand tomato. The first objective was to analyze gene expression profiles of susceptible tomato plants infected with pathogenic and endophytic Cmmstrains. Microarray analysis identified 122 genes that were differentially expressed during early stages of infection. Cmm activated typical basal defense responses in the host including induction of defense-related genes, production of scavenging of free oxygen radicals, enhanced protein turnover and hormone synthesis. Proteomic investigation of the Cmm-tomato interaction was performed with Multi-Dimensional Protein Identification Technology (MudPIT) and mass spectroscopy. A wide range of enzymes secreted by Cmm382, including cell-wall degrading enzymes and a large group of serine proteases from different families were identified in the xylem sap of infected tomato. Based on proteomic results, the expression pattern of selected bacterial virulence genes and plant defense genes were examined by qRT-PCR. Expression of the plasmid-borne cellulase (celA), serine protease (pat-1) and serine proteases residing on the chp/tomA pathogenicity island (chpCandppaA), were significantly induced within 96 hr after inoculation. Transcription of chromosomal genes involved in cell wall degradation (i.e., pelA1, celB, xysA and xysB) was also induced in early infection stages. The second objective was to identify by VIGS technology host genes affecting Cmm multiplication and appearance of disease symptoms in plant. VIGS screening showed that out of 160 tomato genes, which could be involved in defense-related signaling, suppression of 14 genes led to increase host susceptibility. Noteworthy are the genes Snakin-2 (inhibitor of Cmm growth) and extensin-like protein (ELP) involved in cell wall fortification. To further test the significance of Snakin -2 and ELP in resistance towards Cmm, transgenic tomato plants over-expressing the two genes were generated. These plants showed partial resistance to Cmm resulting in a significant delay of the wilt symptoms and reduction in size of canker lesion compared to control. Furthermore, colonization of the transgenic plants was significantly lower. The third objective was to assess the involvement of ethylene (ET), jasmonate (JA) and salicylic acid (SA) in Cmm infection. Microarray and proteomic studies showed the induction of enzymes involved in ET and JA biosynthesis. Cmm promoted ET production 8 days after inoculation and SIACO, a key enzyme of ET biosynthesis, was upregulated. Inoculation of the tomato mutants Never ripe (Nr) impaired in ET perception and transgenic plants with reduced ET synthesis significantly delayed wilt symptoms as compared to the wild-type plants. The retarded wilting in Nr plants was shown to be a specific effect of ET insensitivity and was not due to altered expression of defense related genes, reduced bacterial population or decrease in ethylene biosynthesis . In contrast, infection of various tomato mutants impaired in JA biosynthesis (e.g., def1, acx1) and JA insensitive mutant (jai1) yielded unequivocal results. The fourth objective was to determine the role of cell wall degrading enzymes produced by Cmm in xylem colonization and symptoms development. A significance increase (2 to 7 fold) in expression of cellulases (CelA, CelB), pectate lyases (PelA1, PelA2), polygalacturonase and xylanases (XylA, XylB) was detected by qRT-PCR and by proteomic analysis of the xylem sap. However, with the exception of CelA, whose inactivation led to reduced wilt symptoms, inactivation of any of the other cell wall degrading enzymes did not lead to reduced virulence. Results achieved emphasized the complexity involved in Cmm-tomato interactions. Nevertheless they provide the basis for additional research which will unravel the mechanism of Cmm pathogenicity and formulating disease control measures.