Готові списки джерел за темами / Communications cellules

Добірка наукової літератури з теми "Communications cellules"

Автор: Grafiati
Опубліковано: 7 вересня 2022

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Статті в журналах з теми "Communications cellules"

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Després, Merlin, and Simon Gaudin. "Le monoxyde d’azote: Une arme du système immunitaire pour brouiller les communications entre bactéries." médecine/sciences 36, no. 11 (November 2020): 1074–77. http://dx.doi.org/10.1051/medsci/2020214.

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Анотація:
Le dossier thématique suivant a été rédigé par les étudiantes et étudiants de Master 1 de Biologie de l’École Normale Supérieure de Lyon à l’issue de l’UE Microbiologie Moléculaire et Structurale (2019-2020). Le Master de Biologie de l’ENS de Lyon, cohabilité par l’université Claude Bernard Lyon 1, accueille chaque année environ 50 étudiants en M1 et en M2 et propose une formation de haut niveau à la recherche en biosciences. Chaque étudiant y construit son parcours à la carte, en choisissant ses options parmi un large panel de modules, favorisant ainsi une approche pluridisciplinaire des sciences du vivant, et ce en relation étroite avec les laboratoires de recherche du tissu local, national et international. En participant à diverses activités scientifiques connexes aux UE de leur formation, les étudiants préparent également l’obtention du Diplôme de l’ENS de Lyon, qui valide leur scolarité à l’ENS. La rédaction du présent dossier, qui vise à transmettre de façon claire les messages issus d’une sélection d’articles scientifiques publiés récemment dans le domaine de la microbiologie, constitue l’une de ces activités connexes proposées aux étudiants. Les bactéries peuvent vivre en communautés dont la structure est régulée par de nombreuses interactions abiotiques et biotiques. Les interactions biotiques reposent sur des communications inter-bactériennes qui participent à la mise en place de relations de collaboration, de compétition ou de prédation. Ces communautés bactériennes peuvent en outre être en interaction avec des hôtes animaux, dans le cas des bactéries du microbiote ou des bactéries pathogènes par exemple, ou avec des virus parasites, les bactériophages. Le présent dossier illustre quelques aspects nouveaux de cette communication bactérienne, et de la façon dont les interactions bactéries/hôte ou bactéries/phages peuvent impacter cette communication. Deux nouvelles s’attardent sur des découvertes récentes autour du quorum sensing, une modalité de communication bactérienne permettant l’expression coordonnée des gènes à l’échelle de la population, en fonction de la densité de la population. La nouvelle intitulée « Le monoxyde d’azote : une arme du système immunitaire pour brouiller les communications entre bactéries » illustre comment le quorum sensing chez Staphylococcus aureus, une bactérie opportuniste, peut être affecté par un médiateur du système immunitaire de la souris. La nouvelle intitulée « Un bactériophage exploite le système de communication de son hôte bactérien pour entrer en cycle lytique » montre une stratégie étonnante par laquelle le phage VP882 décrypte des signaux issus du quorum sensing de la bactérie qu’il infecte pour réguler son propre cycle de réplication. Au-delà du quorum sensing, deux nouvelles décrivent de nouvelles modalités de communication inter-bactérienne. La nouvelle intitulée « Les nanotubes bactériens, acteurs de la compétition entre Bacillus subtilis et Bacillus megaterium » met en lumière le rôle des nanotubes, des structures de communication intercellulaire insoupçonnées jusque récemment chez les bactéries. La nouvelle intitulée « La bactérie Vibrio cholerae lyse les bactéries environnantes et assimile leur ADN qu’elle intègre dans son propre génome » illustre comment un système de sécrétion, qui permet l’injection d’effecteurs bactériens dans des cellules cibles, peut être exploité pour faciliter les transferts horizontaux de gènes chez les bactéries. Enfin, pour élargir la réflexion au monde des virus eucaryotes, deux nouvelles montrent comment l’infection virale peut interférer avec la communication entre cellules eucaryotes, sur l’exemple de la communication s’effectuant par l’intermédiaire de vésicules extracellulaires. La nouvelle intitulée « La sécrétion de vésicules extracellulaires par les plaquettes activées à l’origine de la létalité de la dengue ? » discute des mécanismes par lesquels le virus de la dengue déclenche la sécrétion de vésicules extracellulaires par les plaquettes, et des conséquences que cela peut avoir sur l’inflammation et le déclenchement de chocs hémorragiques. La nouvelle intitulée « Le coccolithovirus et Emiliania huxleyi : le détournement viral des vésicules extracellulaires » montre enfin comment ce virus d’algue unicellulaire exploite la communication intercellulaire de son hôte pour augmenter son pouvoir de diffusion au sein de la population, et des conséquences écologiques et géochimiques que cela peut entraîner à grande échelle.
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JANIS, Pekka, Chia-Hao YU, Klaus DOPPLER, Cassio RIBEIRO, Carl WIJTING, Klaus HUGL, Olav TIRKKONEN, and Visa KOIVUNEN. "Device-to-Device Communication Underlaying Cellular Communications Systems." International Journal of Communications, Network and System Sciences 02, no. 03 (2009): 169–78. http://dx.doi.org/10.4236/ijcns.2009.23019.

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Y.S.V.Raman, Y. S. V. Raman, Dr S. Sri Gowri Dr S.Sri Gowri, and Dr B. Prabharkara Rao. "Performance Enhancement of Dynamic Channel Allocation in Cellular Communication System." Indian Journal of Applied Research 3, no. 7 (October 1, 2011): 322–25. http://dx.doi.org/10.15373/2249555x/july2013/99.

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M.P., Haripriya, and Venkadesh P. "Investigation Study on Secured Data Communication on 5G Cellular Networks." Journal of Advanced Research in Dynamical and Control Systems 11, no. 11-SPECIAL ISSUE (November 20, 2019): 323–30. http://dx.doi.org/10.5373/jardcs/v11sp11/20193038.

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Doh, Inshil, Jiyoung Lim, Shi Li, and Kijoon Chae. "Pairwise and group key setup mechanism for secure machine-to-machine communication." Computer Science and Information Systems 11, no. 3 (2014): 1071–90. http://dx.doi.org/10.2298/csis130922065d.

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Анотація:
In the ubiquitous environment, more and more devices are deployed in our daily life, and need to communicate with one another. M2M (Machine-to-Machine) communication is considered to be one of the major issues in future networks. M2M is expected to bring various benefits in wireless communications when it is interconnected with cellular networks. Considering the characteristics of cellular M2M networks, traditional security solutions are not proper to be applied to cellular M2M networks because the M2M network itself is vulnerable to various attacks. We consider security aspects for cellular M2M communications and propose a key management mechanism including the pairwise key and group key establishment. Our proposal could provide reliability and efficiency for the cellular M2M communication network in the secure manner.
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Combarnous, Yves, and Thi Mong Diep Nguyen. "Cell Communications among Microorganisms, Plants, and Animals: Origin, Evolution, and Interplays." International Journal of Molecular Sciences 21, no. 21 (October 28, 2020): 8052. http://dx.doi.org/10.3390/ijms21218052.

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Cellular communications play pivotal roles in multi-cellular species, but they do so also in uni-cellular species. Moreover, cells communicate with each other not only within the same individual, but also with cells in other individuals belonging to the same or other species. These communications occur between two unicellular species, two multicellular species, or between unicellular and multicellular species. The molecular mechanisms involved exhibit diversity and specificity, but they share common basic features, which allow common pathways of communication between different species, often phylogenetically very distant. These interactions are possible by the high degree of conservation of the basic molecular mechanisms of interaction of many ligand–receptor pairs in evolutionary remote species. These inter-species cellular communications played crucial roles during Evolution and must have been positively selected, particularly when collectively beneficial in hostile environments. It is likely that communications between cells did not arise after their emergence, but were part of the very nature of the first cells. Synchronization of populations of non-living protocells through chemical communications may have been a mandatory step towards their emergence as populations of living cells and explain the large commonality of cell communication mechanisms among microorganisms, plants, and animals.
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Armstrong, John. "Cellular communication." Nature 359, no. 6394 (October 1992): 441. http://dx.doi.org/10.1038/359441a0.

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Das, Sree Krishna, and Md Farhad Hossain. "A Distance Based Communication Mode Selection Mechanism for M2M Communications Over Cellular Networks." Wireless Personal Communications 115, no. 3 (October 7, 2020): 2501–14. http://dx.doi.org/10.1007/s11277-020-07693-5.

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Collins, Hugh. "Cellular radio communications." Facilities 3, no. 3 (March 1985): 10–14. http://dx.doi.org/10.1108/eb006332.

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Goodman, D. J. "Cellular packet communications." IEEE Transactions on Communications 38, no. 8 (1990): 1272–80. http://dx.doi.org/10.1109/26.58761.

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Більше джерел

Дисертації з теми "Communications cellules"

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Sigillo, Francesco. "Importance des cytokines dans les communications entre les cellules de Sertoli et les cellules germinales dans le testicule de rat." Lyon 1, 1999. http://www.theses.fr/1999LYO1T136.

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Mesnil, Marc. "Rôle possible des communications jonctionnelles intercellulaires dans la cancérogénèse." Lyon 1, 1989. http://www.theses.fr/1989LYO1T050.

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Houeto, Fabien. "Affectation de cellules à des commutateurs dans les réseaux de communications personnelles." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape7/PQDD_0017/MQ48857.pdf.

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Laffont, Benoit. "Étude du rôle extra-plaquettaire des microARN : implication des microparticules de plaquettes dans les communications intercellulaires." Doctoral thesis, Université Laval, 2015. http://hdl.handle.net/20.500.11794/26138.

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Анотація:
Tableau d’honneur de la Faculté des études supérieures et postdoctorales, 2015-2016
Les plaquettes sanguines contiennent une quantité abondante et diversifiée de microARN, qui sont de petits ARN non-codants d’une vingtaine de nucléotides de long capables de réguler l’expression des gènes de manière post-transcriptionnelle et séquence spécifique. Suite à leur activation, les plaquettes libèrent des microparticules (MPs), qui contiennent du matériel génétique issu de leur cellule d’origine et susceptible d’être transmis à une autre cellule afin d’y exécuter une fonction biologique. Durant mes travaux de thèse, j’ai étudié le rôle extra-plaquettaire des microARN et la capacité des MPs de plaquettes à participer aux communications intercellulaires. Les résultats que j’ai obtenus démontrent que les plaquettes activées à la thrombine libèrent la majorité de leur contenu en microARN dans les MPs, notamment miR-223. Les MPs sont internalisées par les cellules endothéliales HUVEC, et y délivrent leur contenu en miR-223. De plus, les MPs contiennent des complexes effecteurs Argonaute 2 (Ago2)•miR-223 fonctionnels et capables de réguler l’expression d’un gène rapporteur dans les cellules cibles endothéliales. Enfin, miR-223 provenant des MPs est capable de réguler l’expression de deux gènes endogènes prédits pour être ciblés par miR-223 et présents dans les HUVEC, à la fois au niveau de l’ARN messager (ARNm) et de la protéine. Dans une deuxième étude, j’ai démontré que ce phénomène n’est pas exclusif aux cellules endothéliales et qu’il peut également se produire avec les macrophages primaires humains. Les MPs sont effectivement internalisées par les macrophages et y délivrent leur contenu en miR-126-3p, qui y est fonctionnel et y régule l’expression d’un gène rapporteur et de gènes endogènes. De plus, l’internalisation des MPs induit une modification du transcriptome des macrophages receveurs, avec 66 microARN et 653 ARN codants ou non codants dont les profils d’expression sont modifiés. Ces changements sont accompagnés d’une diminution de la sécrétion de cytokines et de chimiokines, et d’une augmentation de la capacité de phagocytose par les macrophages. Mes travaux de doctorat démontrent que les microARN véhiculés par les MPs plaquettaires sont impliqués dans la reprogrammation de l’expression des gènes et des fonctions des cellules les internalisant, reflétant ainsi la complexité des communications intercellulaires.
Blood platelets contain an abundant and diverse array of microRNAs, which are small non-coding RNAs of ~20 nucleotides involved in post-transcriptional regulation of gene expression in a sequence-specific manner. Upon activation, platelets release microparticles (MPs) containing genetic materials from their parental cells that may be transferred to, and exert potent biological effects in, recipient cells. During my PhD thesis, I studied the extra-platelet role of microRNAs, and the ability of platelet-derived MPs to mediate cell-to-cell communications. The results that I obtained demonstrate that thrombin-activated platelets preferentially release their microRNA content in MPs, including miR-223. MPs can be internalized by human umbilical vein endothelial cells (HUVEC), to which they transfer their miR-223 content. Moreover, platelet MPs contain functional effector Argonaute 2 (Ago2)•miR-223 complexes that are capable of regulating expression of a reporter gene in recipient HUVEC. Finally, platelet MP-derived miR-223 could regulate expression of two endogenous genes in recipient HUVEC, both at the mRNA and protein levels. In a second study, I demonstrated that this process is not exclusive to endothelial cells, and could take place also in primary human macrophages. Following their internalization by macrophages, MPs deliver functional miR-126-3p, which regulated expression of both a reporter gene and endogenous genes. Furthermore, MP internalization modified the transcriptome of recipient macrophages, with 66 microRNAs and 464 coding and non-coding RNAs that are differentially expressed. These changes are associated with a reduced secretion of cytokines and chemokines, and a marked increase in the phagocytic capacity of macrophages. My doctoral work demonstrate that platelet-derived microRNAs transfered by MPs are involved in reprograming recipient cells’ gene expression and functions, which illustrate the growing complexity of cell-to-cell communications.
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BOURDON, VERONIQUE. "Etablissement et caracterisation d'une lignee de cellules de sertoli pour l'etude des communications intercellulaires dans le testicule." Nice, 1997. http://www.theses.fr/1997NICE5206.

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Анотація:
L'analyse de la fonction sertolienne se heurte a la complexite des interactions existantes dans le testicule et aux problemes lies aux cultures primaires. Pour la plupart d'entre elles, les lignees de cellules de sertoli sont issues d'animaux immatures et/ou ont un phenotype proche de cellules transformees. Nous avons utilise des familles de souris transgeniques exprimant l'antigene grand t du virus polyome (pylt). L'oncogene plt qui code pour pylt induit l'immortalisation cellulaire, les cellules se multiplient en culture et ont des caracteristiques de cellules normales et n'evoluent pas vers un phenotype de cellules transformees. Une lignee, 42gpa9, a ete etablie a partir de cellules de sertoli issues de testicules histologiquement et fonctionnellement normaux de males pylt adultes. Elle est maintenue en culture depuis trois ans. Les cellules possedent des caracteristiques de cellules normales : inhibition de contact, croissance sur support solide, cytosquelette d'actine organise en fibres de tension. Elles sont morphologiquement semblables aux cellules de sertoli et expriment de nombreux caracteres sertoliens (transferrine, sgp-2, scf, tpa) sans exprimer de marqueurs leydigiens ou germinaux (3-hsd, ldh-x). Les cellules de la lignee 42gpa9 ont conserve une intense activite phagocytosique et repondent a la fsh. Elles forment a confluence des complexes jonctionnels, comparables a ceux observes in vivo, composes de jonctions serrees et communicantes. In situ, les cellules de sertoli sont soumises a divers types de regulation (endocrine, et locales). La lignee 42gpa9 nous a servi de modele pour etudier deux formes de regulations locales, d'une part, l'influence de la phagocytose sur le systeme activateur du plasminogene sertolien et d'autre part d'apprehender le role des jonctions communicantes et de leurs proteines contitutives, les connexines, dans la communication cellule a cellule au sein de l'epithelium seminifere.
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Jaffredo, Manon. "Communications intercellulaires dynamiques au sein des îlots pancréatiques analysées par multi-electrode arrays : rôles physiologiques et applications biotechnologiques en diabétologie." Thesis, Bordeaux, 2021. http://www.theses.fr/2021BORD0120.

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Les îlots pancréatiques sont le principal capteur de glycémie et intègrent toutes les informations métaboliques et hormonales pour adapter en temps réel la sécrétion des hormones, telles que l'insuline par les cellules β majoritaires et le glucagon par les cellules α. Dans le diabète de type 1 (DT1) les cellules β sont détruites par réaction auto-immune et dans le DT2 la masse de cellules β, la fonction et le réseau intra-îlot sont altérés. La réactivité de ces micro-organes est due à leurs propriétés électriques, encodant rapidement l’information, et aux communications entre cellules β/β et β/non-β. Cependant des outils non-invasifs à haute résolution et long terme pour les analyser manquent. L’électrophysiologie extracellulaire par multi-electrode arrays (MEAs) le permet en mesurant des signaux cellulaires mais aussi multicellulaires (SPs) dus aux couplages entre cellules β. J’ai donc utilisé les MEAs (i) pour explorer la physiologie/physiopathologie des îlots et (ii) pour des applications en diabétologie. J’ai montré que la cinétique biphasique de la sécrétion d’insuline était encodée par les SPs avec des changements dynamiques de couplages entre cellules β. Une hormone intestinale importante (GLP-1) augmente la 2de phase alors que des conditions diabétiques (glucotoxicité) réduisent la 1re. La réponse aux nutriments requiert de plus la coopération avec les cellules α, car leur suppression (modèle inductible GluDTR) réduit l’activité basale et la 2de phase des cellules β en présence d’un mélange physiologique d’acides aminés. J’ai également caractérisé électrophysiologiquement les cellules β humaines dérivées de cellules souches pluripotentes induites (iPSC), déterminé leurs couplages, établi leur contrôle qualité et démontré l’impact fonctionnel d’une mutation d’intérêt (ZnT8) éditée par CRISPR/Cas9. Un contrôle qualité fonctionnel des îlots humains avant greffe chez des patients DT1 a également été réalisé et comparé aux résultats cliniques. Enfin, mes enregistrements de SPs analysées par microélectronique en temps réel ont permis de valider un modèle in silico de biocapteur dans un simulateur de référence de patients DT1. En conclusion, mes travaux montrent (i) l’importance des communications intra-îlots dans leur adaptation physiologique dynamique, (ii) et que l’exploitation des SPs ouvre des applications allant du pancréas artificiel à la thérapie cellulaire personnalisée
Pancreatic islets are the main sensor of glycaemia and they integrate all the metabolic and hormonal inputs to adapt in real time the secretion of hormones such as insulin by β cells and glucagon by α cells. In type 1 diabetes (T1D) β cells are destroyed by immune attack, and in T2D, β cell mass, function and the intra-islet network are altered. The islet micro-organs are highly reactive due to their electrical properties encoding rapid information and due to intercellular communications between β cells and β/non-β cells. Nevertheless, non-invasive, high resolution and long-term approaches for analysis are still lacking. Extracellular electrophysiology with multi-electrode arrays (MEAs) allows this analysis of islets by measuring both cellular as well as multicellular signals (SPs) due to β cell coupling. During my PhD, I used MEAs (i) to explore islet physiology/pathophysiology and (ii) for biotechnological applications in diabetology. I have shown that biphasic kinetics of insulin secretion are encoded by SPs through dynamic changes in β cell coupling. An important intestinal hormone (GLP-1) increases the 2nd phase of β-cell activity while diabetic conditions (glucotoxicity) reduce the 1st phase. Islet responses to nutrients also require α/β cell cooperation since α cell ablation in the inducible GluDTR mice model reduced both the basal and 2nd phase of β cell activity generated by glucose and a physiological mix of amino acids. I have also performed the electrophysiological characterization of human β cells derived from induced pluripotent stem cells (iPSC), determined their coupling, established their quality control and shown the functional impact of a mutation of interest (ZnT8) edited by CRISPR/Cas9. A functional quality control of human islets prior to transplantation in T1D patients was also performed for correlations with clinical data. Finally, my SP recordings analyzed in real time by microelectronics has contributed to validate an in silico model of biosensor in a FDA-approved simulator of T1D patients. In conclusion, my work demonstrates (i) the role of intra-islet communications in the dynamic physiological adaptation of these micro-organs, (ii) and that detailed characterization of SPs opens new applications from artificial pancreas to personalized cell therapy
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Milon, Marie-Anne. "Modélisation de cellules déphaseuses environnées : Application à l'analyse de réseaux réflecteurs imprimés." Rennes, INSA, 2001. http://www.theses.fr/2007ISAR0022.

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Анотація:
Le contexte dans lequel s'inscrit ce travail est celui des réseaux réflecteurs plans imprimés passifs au rayonnement directif et transversal. Ce travail de thèse s'attache à analyseret modeliser en détails le fonctionnement de cellules et de réseaux réflecteurs existants et propose de nouveaux outils pour investiguer les effets du couplage et ceux de la réflexion spéculaire sur le plande l'antenne. On propose ici d'appliquer la FDTD a la simulation de ces cellules élémentaires, en tenan compte de l'effet de leur environnement. Une nouvelle approche pour la modélisation des cellulesde réseau réflecteur est présentée et validée en particulier, cette approche permet de prendre en compte et de caractériser les effets liés à la réflexion spéculaire et au couplage mutuel. En outre, ce travail propose une amélioration de la rétro-simulation du réseau complet afin de mieux en estimer le rayonnement et prend désormais en compte l'illumination réelle de la source primaire utilisée
This study is focusing on flat passive microstrip reflectarrays with brodadside and directive radiation. This thesis is dedicated to both analyse and modelize the unitary cell behaviour of existing reflectarrays. New simulation tools are proposed to study mutual coupling and specualr reflection effects. The FDTD analysis of a unitary reflectarray cell is appllied to take into account environment effects. A new approcah to analyse reflectarray cell is presented and validated. This approach considers the actual mutual coupling for a realistic configuration with non identical cells and also characterise the specular reflection effect. Moreover , this work provides an improvement of the whole reflectarray simlulation, which accounts for the real illumination of the primary source
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Fauquier, Teddy. "LES CELLULES FOLLICULOSTELLAIRES : UNITES FONCTIONNELLES D'UNE VOIE DE COMMUNICATION A LONGUE DISTANCE DANS L'HYPOPHYSE ANTERIEURE." Phd thesis, Université Montpellier II - Sciences et Techniques du Languedoc, 2001. http://tel.archives-ouvertes.fr/tel-00770829.

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L'hypophyse antérieure assure une interface endocrine entre le cerveau et les organes périphériques. En effet, cette glande sécrète de manière pulsatile ses différentes hormones dans la circulation générale sous l'influence de facteurs hypothalamiques déversés épisodiquement dans le système porte de l'éminence médiane. Toutefois, l'influence hypothalamique ne saurait à elle seule expliquer l'harmonisation des sécrétions des cellules d'un même type endocrine, qui sont distribuées de manière hétérogène au sein du parenchyme. Il existe sans doute des mécanismes permettant de coordonner l'activité des cellules endocrines à l'échelle de la glande entière. Au cours de cette thèse, nous avons montré la présence d'un mécanisme de communication intra-hypophysaire permettant un transfert rapide d'information au sein d'un réseau de cellules non-endocrines, les cellules folliculostellaires (FS). Ce travail réalisé sur des tranches épaisses d'hypophyse de rat, modèle qui maintient intacte l'architecture cordonale du tissu, a permis de mettre en évidence l'excitabilité membranaire des cellules FS, propriété jusqu'alors inconnue. Cette excitabilité sert de base à l'initiation de vagues calciques, qui peuvent se propager rapidement via des jonctions gap à des régions éloignées de la glande. Nous avons également étudié la libération d'interleukine-6 (IL-6) par les cellules FS. Cette cytokine est connue pour stimuler l'ensemble des sécrétions hormonales hypophysaires. La production d'IL-6 est stimulée par le PACAP. Ce neuropeptide semble agir directement au niveau du gène, et son effet dépend de l'état des communications intercellulaires au sein du réseau. Les cellules FS pouvant répondre à des stimuli d'origine centrale et périphérique, ainsi que dialoguer avec les cellules endocrines, l'ensemble de ces résultats montre que le réseau de cellules FS pourrait fournir un mécanisme efficace qui coordonnerait le fonctionnement de la glande en fonction des différents états physiologiques
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Adane, Yacine. "Caractérisation inverse de sources pour l'évaluation de l'exposition humaine aux ondes électromagnétiques émises par les antennes de station de base." Paris 6, 2004. http://www.theses.fr/2004PA066348.

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Caicedo, Andrès. "Communication cellule-cellule : transfert de mitochondries provenant des cellules souches/stromales mesenchymateuses (CSM) vers des cellules cancereuses." Thesis, Montpellier 1, 2013. http://www.theses.fr/2013MON1T036.

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Au début de ma thèse, je me suis intéressé aux processus qui sous-tendent la communication cellulaire et plus spécifiquement les interactions cellule-cellule. Pourquoi une cellule établit-elle un contact spécifique avec une autre cellule ? Comment les cellules répondent-elles à cette interaction et quels en sont les effets ? J'ai utilisé comme modèle d'étude l'interaction entre les cellules souches/stromales mésenchymateuses (CSM) et des lignées de cancer du sein. L'objectif de mon travail a été d'analyser les mécanismes de ces interactions entre CSM et cellules cancéreuses et d'en évaluer les effets sur les fonctions des cellules cancéreuses. En effet, des mécanismes de recrutement des CSM aux sites tumoraux ont été décrits avec des effets sur la progression tumorale, ce qui ouvre par ailleurs des perspectives pour de nouvelles approches thérapeutiques. J'ai tout d'abord développé un système expérimental de microscopie confocale en temps réel pour observer le type d'interaction qui est produit entre les CSM humaines et les cellules de carcinomes mammaires MDA-MB-231 et MCF7. J'ai constaté la formation dynamique de structures tubulaires entre les deux types cellulaires et, de façon surprenante, le passage des mitochondries des CSM vers les cellules cancéreuses. En un deuxième temps, j'ai utilisé un système d'invasion dans une matrice 3D de collagène, que nous avons adapté à la coculture, afin d'observer les effets de l'interaction des MDA-MB-231 avec les CSM. En accord avec la littérature, nous avons constaté une augmentation du pouvoir invasif des cellules cancéreuses, effet qui pouvait être lié au transfert des mitochondries provenant des CSM. Pour répondre à cette question, j'ai mis au point un protocole pour transférer spécifiquement des mitochondries, isolées à partir de cellules, vers d'autres cellules. Ce protocole, exploité dans ce manuscrit pour le transfert de mitochondries de CSM vers les cellules cancéreuses MDA-MB-231, peut être transposé à d'autres types cellulaires et fait l'objet d'une demande de brevet. Nos données indiquent que l'acquisition de mitochondries de CSM par les cellules cancéreuses modifie leurs propriétés fonctionnelles et augmente leur capacité de prolifération et d'invasion. Concernant leur activité métabolique, on observe une augmentation de leur respiration mitochondriale et de leur production d'ATP. Nos données préliminaires suggèrent aussi une augmentation de l'expression transcriptionnelle d'enzymes impliquées dans la synthèse des lipides et l'oxydation des acides gras. Ces données, générées grâce au protocole de transfert artificiel de mitochondries mis au point, montrent pour la première fois que les mitochondries des CSM peuvent majorer certaines propriétés cellulaires liées à la progression tumorale, comme la prolifération et l'invasion, et contribuer à une reprogrammation métabolique des cellules cancéreuses. Elles s'intègrent au rôle proposé par la communauté scientifique pour les CSM dans le microenvironnement tumoral. La technique de transfert artificiel de mitochondries nous permettra de répondre à d'autres questions restées ouvertes, comme le rôle possible des mitochondries des CSM dans les résistances développées par les tumeurs vis-à-vis des agents anti-cancéreux. Le protocole de transfert de mitochondries développé au laboratoire constitue une technique de choix et offre de nombreux avantages comparativement à d'autres techniques comme la micro-injection et la génération des hybrides cytoplasmiques. Sa mise en œuvre est en effet simple et reproductible et permet de traiter une grande quantité de cellules. Cette méthode permet d'envisager de nombreuses perspectives et applications dans le domaine de la reprogrammation métabolique, comme par exemple de restaurer les capacités d'une cellule dysfonctionnelle par le transfert de mitochondries issues d'une cellule saine et « métaboliquement active »
At the beginning of my thesis, I was interested in the process involved in cell communication, more specifically in cell-to-cell interactions. Why does a cell specifically establish contacts with another one, how do cells respond to these interactions and what are the effects? As a model to answer these questions, I studied the interactions between MSCs and two breast cancer cell lines. The study of the communications between MSCs and tumor cells is an alternative to explore and understand tumor progression. MSC recruitment to the tumor is shown to favor the progression of the disease. The mechanisms of this dialogue are multiple and are the object of a great number of studies that aim at finding new therapeutic approaches. The objective of this work was to analyze the interactions between MSCs and cancer cells and evaluate the potential effects of this communication in tumor progression. First, I developed an experimental system of real time confocal microscopy in order to observe the interaction produced between MSCs and the breast carcinoma MDA-MB-231 and MCF-7 cells. I noticed the dynamic formation of tubular structures between the two different cell types and, surprisingly, the passage of mitochondria from MSCs to the cancer cells. Second, we used a 3D system of cell invasion in a collagen matrix, which we adapted for the coculture, in order to observe the effects of the interactions between the MDA-MB-231 and MSCs. In agreement with the literature, we observed an increase in the migratory potential of the cancer cells, an effect that could be linked to the transfer of mitochondria from MSCs to the cancer cells. To answer this question, I set up a protocol to specifically transfer to the cancer cells mitochondria isolated from the MSCs and test directly the functional consequences for the cancer cells. This protocol can be used to transfer mitochondria, not only from MSCs but also from other cells. This method is currently submitted to a patent process. Our results show that the transfer of MSC mitochondria to the cancer cells modifies cancer cells functional properties and increase their invasive and proliferative capacities. Concerning the metabolic activity, we noticed an increase in mitochondrial respiration and ATP production. We also observed an increase in the transcription level of enzymes related to the lipid synthesis and fatty acid oxidation. The results generated with this new protocol of mitochondria transfer show, for the first time, that mitochondria originating from MSCs can improve cellular capacities linked to the tumor progression. The role proposed by the scientific community for the interactions of MSCs with the tumor cells fits with the data generated in our work. Several questions remain open. In particular, could the transfer of mitochondria from MSCs to the cancer cells contribute to the acquisition of resistance to anti-cancer agents observed in patients? The protocol of transfer of mitochondria that we developed in the laboratory is a technique of choice and offers many advantages over other techniques such as microinjection and cytoplasmic hybrids; its implementation is simple and reproducible and can target large numbers of cells. This method opens numerous perspectives and potential applications such as the study of metabolic reprogramming. Thus, we could consider restoring the activity of dysfunctional cells by transferring mitochondria from “metabolically active” or healthy cells. In the long term, one of the applications could be transferring healthy or genetically modified mitochondria to zygotes carrying mitochondrial DNA mutations, in order to treat pathologies like infertility, neuro-degenerative diseases, cancer and premature aging
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Книги з теми "Communications cellules"

1

Combarnous, Yves. Biochimie des communications cellulaires: Hormones, neuromédiateurs, cytokines, facteurs de croissance. 2nd ed. Paris: Technique et Documentation-Lavoisier, 1996.

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2

Leibowitz, Dennis. The cellular communications industry. New York, N.Y. (140 Broadway, New York 10005): Donaldson, Lufkin & Jenrette, 1985.

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3

Amasino, Richard M., ed. Cellular Communication in Plants. Boston, MA: Springer US, 1993. http://dx.doi.org/10.1007/978-1-4757-9607-0.

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4

A, García-Martín Miguel, ed. The 3G multimedia subsystem (IMS): Merging the internet and the cellular worlds. Chichester, West Sussex: J. Wiley, 2004.

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5

Garrard, Garry A. Cellular communications: Worldwide market development. Boston, MA: Artech House, 1998.

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6

Pattan, Bruno. Satellite-based global cellular communications. New York: McGraw-Hill, 1998.

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7

Huang, Howard, Constantinos B. Papadias, and Sivarama Venkatesan. MIMO Communication for Cellular Networks. Boston, MA: Springer US, 2012. http://dx.doi.org/10.1007/978-0-387-77523-4.

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8

CDMA cellular mobile communications & network security. Upper Saddle River, NJ: Prentice Hall PTR, 1998.

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9

Ghorbanzadeh, Mo, Ahmed Abdelhadi, and Charles Clancy. Cellular Communications Systems in Congested Environments. Cham: Springer International Publishing, 2017. http://dx.doi.org/10.1007/978-3-319-46267-7.

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10

Washington (State). Dept. of Revenue. Cellular communications study: Report to the Legislature on taxation of cellular communications in Washington State. [Olympia, Wash.]: The Dept., 1993.

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Частини книг з теми "Communications cellules"

1

Tzianabos, Arthur O., and Lee M. Wetzler. "Cellular Communication." In Immunology, Infection, and Immunity, 343–69. Washington, DC, USA: ASM Press, 2015. http://dx.doi.org/10.1128/9781555816148.ch15.

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Sun, Xiaojuan. "Cellular Communication." In Encyclopedia of Systems Biology, 385–86. New York, NY: Springer New York, 2013. http://dx.doi.org/10.1007/978-1-4419-9863-7_548.

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3

Mämmelä, Aarne, and Risto Wichman. "Cellular Communications Channels." In Handbook of Computer Networks, 577–90. Hoboken, NJ, USA: John Wiley & Sons, Inc., 2011. http://dx.doi.org/10.1002/9781118256114.ch38.

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4

Jagoda, A., and M. de Villepin. "The Cellular Radiotelephone." In Mobile Communications, 79–103. Wiesbaden: Vieweg+Teubner Verlag, 1993. http://dx.doi.org/10.1007/978-3-322-99269-7_6.

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5

Ghosh, R. K. "Cellular Wireless Communication." In Wireless Networking and Mobile Data Management, 21–54. Singapore: Springer Singapore, 2017. http://dx.doi.org/10.1007/978-981-10-3941-6_2.

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6

Egan, Manus. "Cellular Telephones and Racal Vodafone." In Communications, 9–10. London: Macmillan Education UK, 1986. http://dx.doi.org/10.1007/978-1-349-07816-5_3.

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Sheikh, Asrar U. H. "Mobile Wireless Cellular Systems." In Wireless Communications, 549–641. Boston, MA: Springer US, 2004. http://dx.doi.org/10.1007/978-1-4419-9152-2_12.

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Alencar, Marcelo S., and Valdemar C. da Rocha. "Mobile Cellular Telephony." In Communication Systems, 257–81. Cham: Springer International Publishing, 2019. http://dx.doi.org/10.1007/978-3-030-25462-9_9.

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9

Raith, Krister, Erik Lissakers, Jan Uddenfeldt, and Jan Swerup. "Cellular For Personal Communications." In The Kluwer International Series in Engineering and Computer Science, 1–20. Boston, MA: Springer US, 1993. http://dx.doi.org/10.1007/978-1-4615-3162-3_1.

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Zhang, Hongliang, Lingyang Song, and Zhu Han. "UAV Assisted Cellular Communications." In Wireless Networks, 61–100. Cham: Springer International Publishing, 2019. http://dx.doi.org/10.1007/978-3-030-33039-2_3.

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Тези доповідей конференцій з теми "Communications cellules"

1

Wang, Yuhang, Zhiyong Chen, Yao Yao, Manyuan Shen, and Bin Xia. "Secure communications of cellular users in device-to-device communication underlaying cellular networks." In 2014 Sixth International Conference on Wireless Communications and Signal Processing (WCSP). IEEE, 2014. http://dx.doi.org/10.1109/wcsp.2014.6992171.

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Ronny Yongho Kim. "Snoop based group communication scheme in cellular Machine-to-Machine communications." In 2010 International Conference on Information and Communication Technology Convergence (ICTC). IEEE, 2010. http://dx.doi.org/10.1109/ictc.2010.5674824.

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Nematy, Hoda. "Secure Protocol for Four D2D Scenarios." In 2nd International Conference on Machine Learning &Trends (MLT 2021). AIRCC Publishing Corporation, 2021. http://dx.doi.org/10.5121/csit.2021.111102.

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In traditional cellular infrastructure, cellular devices communicate with each other directly even when they are close together. This strategy causes massive traffic to the cellular network therefore D2D communication has introduced to overcome this issue, bring more bandwidth and also higher rates to the cellular network. One of the major challenges for D2D Communication is to have one single secure protocol that can adapt in four D2D scenarios defined in references. These scenarios are Direct D2D and relaying D2D communication with and without cellular infrastructure. In this paper, we propose a Secure D2D protocol based on ARIADNE with TESLA. Also we use LTE-A AKA protocol for authentication and key agreement procedure between Source and Destination. Next, we adapt this scenario to be applicable in without cellular infrastructure ones. This protocol could be used in direct D2D also. Based on the results, our proposed protocol has a few computation overhead compare to recent works and have less communication overhead than SODE with preserve many security properties such as Authentication, Authorization, Confidentiality, Integrity, Secure Key Agreement, Secure Routing Transmission…. We check Authentication, Confidentiality, Reachability and Secure Key Agreement of the proposed protocol with ProVerif verification tools.
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Das, Sree Krishna, and Md Farhad Hossain. "A Location Aware Communication Mode Selection Mechanism for M2M Communications over Cellular Networks." In 2019 5th International Conference on Advances in Electrical Engineering (ICAEE). IEEE, 2019. http://dx.doi.org/10.1109/icaee48663.2019.8975497.

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Chen, Hualiang, Xingyu Deng, Mei Gao, Linna Yang, Lianhua Guo, and Ming Chi. "Location Related Communication Mode Selection and Spectrum Sharing for D2D Communications in Cellular Networks." In 2018 International Conference on Intelligent Transportation, Big Data & Smart City (ICITBS). IEEE, 2018. http://dx.doi.org/10.1109/icitbs.2018.00051.

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Roger, Sandra, Carmen Botella, Enrique E. Meza-Sãnchez, and Juan J. Pérez-Solano. "Communication cost of channel estimation interpolation for group-based vehicular communications in cellular networks." In EATIS 2020: 10th Euro American Conference on Telematics and Information Systems. New York, NY, USA: ACM, 2020. http://dx.doi.org/10.1145/3401895.3402065.

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7

Exell Enrique, Franklin J. "Secure communications using the mobile communications (cellular telephony)." In 2014 IEEE Fourth International Conference on Consumer Electronics - Berlin (ICCEBerlin). IEEE, 2014. http://dx.doi.org/10.1109/icce-berlin.2014.7034278.

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Kilic, Gokhan, and Tolga Girici. "Clustering in cellular M2M communications." In 2014 22nd Signal Processing and Communications Applications Conference (SIU). IEEE, 2014. http://dx.doi.org/10.1109/siu.2014.6830566.

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9

Azari, M. Mahdi, Giovanni Geraci, Adrian Garcia-Rodriguez, and Sofie Pollin. "Cellular UAV-to-UAV Communications." In 2019 IEEE 30th Annual International Symposium on Personal, Indoor and Mobile Radio Communications (PIMRC). IEEE, 2019. http://dx.doi.org/10.1109/pimrc.2019.8904448.

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Mueck, Markus Dominik, Ingolf Karls, Reza Arefi, Thomas Haustein, and Wilhelm Keusgen. "Licensed shared access for wave cellular broadband communications." In 2014 1st International Workshop on Cognitive Cellular Systems (CCS). IEEE, 2014. http://dx.doi.org/10.1109/ccs.2014.6933805.

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Звіти організацій з теми "Communications cellules"

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.

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2

Garrity, John, and Arndt Husar. Digital Connectivity and Low Earth Orbit Satellite: Constellations Opportunities for Asia and the Pacific. Asian Development Bank, April 2021. http://dx.doi.org/10.22617/wps210156-2.

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Satellite communication plays an important role in the global connectivity ecosystem. It connects rural and remote populations, provides backhaul connectivity to mobile cellular networks, and enables rapid communications for emergency and disaster responses. Low Earth orbit constellations may prove to be transformational to the connectivity landscape based on their global coverage and their suitability for areas not served by fiber optic cable networks. The Asian Development Bank’s developing member countries are well placed to benefit from this expansion of internet connectivity. It will be particularly valuable for small island developing states and landlocked developing countries with limited international bandwidth internet.
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3

Dickman, Martin B., and Oded Yarden. Modulation of the Redox Climate and Phosphatase Signaling in a Necrotroph: an Axis for Inter- and Intra-cellular Communication that Regulates Development and Pathogenicity. United States Department of Agriculture, August 2011. http://dx.doi.org/10.32747/2011.7697112.bard.

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The long-term goals of our research are to understand the regulation of sclerotial development and pathogenicity in S. sclerotiorum. The focus in this project is on the elucidation of the signaling events and environmental cues that contribute to broad pathogenic success of S. sclerotiorum. In this proposal, we have taken advantage of the recent conceptual (ROS/PPs signaling) and technical (genome sequence availability and gene inactivation possibilities) developments to address the following questions, as appear in our research goals stated below, specifically concerning the involvement of REDOX signaling and protein dephosphorylation in the regulation of hyphal/sclerotial development and pathogenicity of S. sclerotiorum. Our stated specific objectives were to progress our understanding of the following questions: (i) Which ROS species affect S. sclerotiorum development and pathogenicity? (ii) In what manner do PPs affect S. sclerotiorum development and pathogenicity? (iii) Are PPs affected by ROS production and does PP activity affect ROS production and SMK1? (iv) How does Sclerotinia modulate the redox environment in both host and pathogen? While addressing these questions, our main findings include the identification and characterization the NADPH oxidase (NOX) family in S. sclerotiorum. Silencing of Ssnox1 indicated a central role for this enzyme in both virulence and pathogenic (sclerotial) development, while inactivation of Ssnox2 resulted in limited sclerotial development but remained fully pathogenic. Interestingly, we found a consistent correlation with Ssnox1(involved with pathogenicity) and oxalate levels. This same observation was also noted with Sssod1. Thus, fungal enzymes involved in oxidative stress tolerance,when inactivated, also exhibit reduced OA levels. We have also shown that protein phosphatases (specifically PP2A and PTP1) are involved in morphogenesis and pathogenesis of S. sclerotiorum, demonstrating the regulatory role of these key proteins in the mentioned processes. While probing the redox environment and host-pathogen interactions we determined that oxalic acid is an elicitor of plant programmed cell death during S. sclerotiorum disease development and that oxalic acid suppresses host defense via manipulation of the host redox environment. During the course of this project we also contributed to the progress of understanding S. sclerotiorum function and the manipulation of this fungus by establishing an efficient gene replacement and direct hyphal transformation protocols in S. sclerotiorum. Lastly, both PIs were involved in thegenomic analysis of this necrotrophic fungal pathogen (along with Botrytis cinerea). Our results have been published in 11 papers (including joint papers and refereed reviews) and have set the basis for a continuum towards a better understanding and eventual control of this important pathogen (with implications to other fungal-host systems as well).
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4

El-Rayes, Khaled, and Ernest-John Ignacio. Evaluating the Benefits of Implementing Mobile Road Weather Information Sensors. Illinois Center for Transportation, February 2022. http://dx.doi.org/10.36501/0197-9191/22-004.

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State departments of transportation (DOTs) have traditionally utilized fixed road weather information sensors (RWIS) to improve road safety during inclement weather; enhance the management of labor, equipment, and materials for winter road maintenance; and reduce adverse environmental impacts from road maintenance activities. Despite the benefits of these fixed RWIS sites, their coverage and effectiveness are limited because of their stationary locations. To overcome these limitations, recent advances in mobile road weather information sensing technology and cellular communications have enabled the development of mobile RWIS that can be deployed on vehicles to expand the limited coverage of fixed RWIS networks. Combining mobile RWIS, fixed RWIS networks, automatic vehicle location, and maintenance decision support systems (MDSS) provide DOTs with accurate georeferenced road and weather information that can be used by DOTs to optimize winter road maintenance operations and deicer applications. This report presents the findings of a research project funded by the Illinois Department of Transportation to investigate the effectiveness of mobile RWIS and MDSS in improving winter maintenance operations. This project had the following three objectives. First, conduct a literature review to gather and analyze current practices and latest research studies on mobile RWIS and their use for collecting real-time winter roadway conditions to optimize winter maintenance operations. Second, perform interviews with other state DOTs to gather and analyze their experiences and best management practices for the deployment and use of mobile RWIS and MDSS. Third, develop recommendations for a pilot study to evaluate the deployment and performance of mobile RWIS and MDSS in order to determine their effectiveness, implementation requirements, software/technology needs, operational challenges, and life-cycle costs.
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5

Rafaeli, Ada, Russell Jurenka, and Chris Sander. Molecular characterisation of PBAN-receptors: a basis for the development and screening of antagonists against Pheromone biosynthesis in moth pest species. United States Department of Agriculture, January 2008. http://dx.doi.org/10.32747/2008.7695862.bard.

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The original objectives of the approved proposal included: (a) The determination of species- and tissue-specificity of the PBAN-R; (b) the elucidation of the role of juvenile hormone in gene regulation of the PBAN-R; (c) the identificationof the ligand binding domains in the PBAN-R and (d) the development of efficient screening assays in order to screen potential antagonists that will block the PBAN-R. Background to the topic: Moths constitute one of the major groups of pest insects in agriculture and their reproductive behavior is dependent on chemical communication. Sex-pheromone blends are utilised by a variety of moth species to attract conspecific mates. In most of the moth species sex-pheromone biosynthesis is under circadian control by the neurohormone, PBAN (pheromone-biosynthesis-activating neuropeptide). In order to devise ideal strategies for mating disruption/prevention, we proposed to study the interactions between PBAN and its membrane-bound receptor in order to devise potential antagonists. Major conclusions: Within the framework of the planned objectives we have confirmed the similarities between the two Helicoverpa species: armigera and zea. Receptor sequences of the two Helicoverpa spp. are 98% identical with most changes taking place in the C-terminal. Our findings indicate that PBAN or PBAN-like receptors are also present in the neural tissues and may represent a neurotransmitter-like function for PBAN-like peptides. Surprisingly the gene encoding the PBAN-receptor was also present in the male homologous tissue, but it is absent at the protein level. The presence of the receptor (at the gene- and protein-levels), and the subsequent pheromonotropic activity are age-dependent and up-regulated by Juvenile Hormone in pharate females but down-regulated by Juvenile Hormone in adult females. Lower levels of pheromonotropic activity were observed when challenged with pyrokinin-like peptides than with HezPBAN as ligand. A model of the 3D structure of the receptor was created using the X-ray structure of rhodopsin as a template after sequence alignment of the HezPBAN-R with several other GPCRs and computer simulated docking with the model predicted putative binding sites. Using in silico mutagenesis the predicted docking model was validated with experimental data obtained from expressed chimera receptors in Sf9 cells created by exchanging between the three extracellular loops of the HezPBAN-R and the Drosophila Pyrokinin-R (CG9918). The chimera receptors also indicated that the 3ʳᵈ extracellular loop is important for recognition of PBAN or Diapause hormone ligands. Implications: The project has successfully completed all the objectives and we are now in a position to be able to design and screen potential antagonists for pheromone production. The successful docking simulation-experiments encourage the use of in silico experiments for initial (high-throughput) screening of potential antagonists. However, the differential responses between the expressed receptor (Sf9 cells) and the endogenous receptor (pheromone glands) emphasize the importance of assaying lead compounds using several alternative bioassays (at the cellular, tissue and organism levels). The surprising discovery of the presence of the gene encoding the PBAN-R in the male homologous tissue, but its absence at the protein level, launches opportunities for studying molecular regulation pathways and the evolution of these GPCRs. Overall this research will advance research towards the goal of finding antagonists for this important class of receptors that might encompass a variety of essential insect functions.
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6

Epel, Bernard L., Roger N. Beachy, A. Katz, G. Kotlinzky, M. Erlanger, A. Yahalom, M. Erlanger, and J. Szecsi. Isolation and Characterization of Plasmodesmata Components by Association with Tobacco Mosaic Virus Movement Proteins Fused with the Green Fluorescent Protein from Aequorea victoria. United States Department of Agriculture, September 1999. http://dx.doi.org/10.32747/1999.7573996.bard.

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The coordination and regulation of growth and development in multicellular organisms is dependent, in part, on the controlled short and long-distance transport of signaling molecule: In plants, symplastic communication is provided by trans-wall co-axial membranous tunnels termed plasmodesmata (Pd). Plant viruses spread cell-to-cell by altering Pd. This movement scenario necessitates a targeting mechanism that delivers the virus to a Pd and a transport mechanism to move the virion or viral nucleic acid through the Pd channel. The identity of host proteins with which MP interacts, the mechanism of the targeting of the MP to the Pd and biochemical information on how Pd are alter are questions which have been dealt with during this BARD project. The research objectives of the two labs were to continue their biochemical, cellular and molecular studies of Pd composition and function by employing infectious modified clones of TMV in which MP is fused with GFP. We examined Pd composition, and studied the intra- and intercellular targeting mechanism of MP during the infection cycle. Most of the goals we set for ourselves were met. The Israeli PI and collaborators (Oparka et al., 1999) demonstrated that Pd permeability is under developmental control, that Pd in sink tissues indiscriminately traffic proteins of sizes of up to 50 kDa and that during the sink to source transition there is a substantial decrease in Pd permeability. It was shown that companion cells in source phloem tissue export proteins which traffic in phloem and which unload in sink tissue and move cell to cell. The TAU group employing MP:GFP as a fluorescence probe for optimized the procedure for Pd isolation. At least two proteins kinases found to be associated with Pd isolated from source leaves of N. benthamiana, one being a calcium dependent protein kinase. A number of proteins were microsequenced and identified. Polyclonal antibodies were generated against proteins in a purified Pd fraction. A T-7 phage display library was created and used to "biopan" for Pd genes using these antibodies. Selected isolates are being sequenced. The TAU group also examined whether the subcellular targeting of MP:GFP was dependent on processes that occurred only in the presence of the virus or whether targeting was a property indigenous to MP. Mutant non-functional movement proteins were also employed to study partial reactions. Subcellular targeting and movement were shown to be properties indigenous to MP and that these processes do not require other viral elements. The data also suggest post-translational modification of MP is required before the MP can move cell to cell. The USA group monitored the development of the infection and local movement of TMV in N. benthamiana, using viral constructs expressing GFP either fused to the MP of TMV or expressing GFP as a free protein. The fusion protein and/or the free GFP were expressed from either the movement protein subgenomic promoter or from the subgenomic promoter of the coat protein. Observations supported the hypothesis that expression from the cp sgp is regulated differently than expression from the mp sgp (Szecsi et al., 1999). Using immunocytochemistry and electron microscopy, it was determined that paired wall-appressed bodies behind the leading edge of the fluorescent ring induced by TMV-(mp)-MP:GFP contain MP:GFP and the viral replicase. These data suggest that viral spread may be a consequence of the replication process. Observation point out that expression of proteins from the mp sgp is temporary regulated, and degradation of the proteins occurs rapidly or more slowly, depending on protein stability. It is suggested that the MP contains an external degradation signal that contributes to rapid degradation of the protein even if expressed from the constitutive cp sgp. Experiments conducted to determine whether the degradation of GFP and MP:GFP was regulated at the protein or RNA level, indicated that regulation was at the protein level. RNA accumulation in infected protoplast was not always in correlation with protein accumulation, indicating that other mechanisms together with RNA production determine the final intensity and stability of the fluorescent proteins.
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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.

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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.
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