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Amit, Vered y Anne-Hélène Kerbiriou. "De la migration de style de vie au mode de vie mobile". Anthropologie et Sociétés 44, n.º 2 (2020): 185. http://dx.doi.org/10.7202/1075685ar.
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Zhang, Qian. "Mongolie intérieure. Désertification, migration et transformation des modes de vie". Hommes & migrations, n.º 1284 (1 de marzo de 2010): 42–55. http://dx.doi.org/10.4000/hommesmigrations.1239.
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Rice, Scott A. y John P. Verboncoeur. "Migration of Multipactor Trajectories via Higher-Order Mode Perturbation". IEEE Transactions on Plasma Science 45, n.º 7 (julio de 2017): 1739–45. http://dx.doi.org/10.1109/tps.2017.2704522.
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Bagchi, Amrit, Bapi Sarker, Jialiang Zhang, Marcus Foston y Amit Pathak. "Fast yet force-effective mode of supracellular collective cell migration due to extracellular force transmission". PLOS Computational Biology 21, n.º 1 (9 de enero de 2025): e1012664. https://doi.org/10.1371/journal.pcbi.1012664.
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Cell collectives, like other motile entities, generate and use forces to move forward. Here, we ask whether environmental configurations alter this proportional force-speed relationship, since aligned extracellular matrix fibers are known to cause directed migration. We show that aligned fibers serve as active conduits for spatial propagation of cellular mechanotransduction through matrix exoskeleton, leading to efficient directed collective cell migration. Epithelial (MCF10A) cell clusters adhered to soft substrates with aligned collagen fibers (AF) migrate faster with much lesser traction forces, compared to random fibers (RF). Fiber alignment causes higher motility waves and transmission of normal stresses deeper into cell monolayer while minimizing shear stresses and increased cell-division based fluidization. By contrast, fiber randomization induces cellular jamming due to breakage in motility waves, disrupted transmission of normal stresses, and heightened shear driven flow. Using a novel motor-clutch model, we explain that such ‘force-effective’ fast migration phenotype occurs due to rapid stabilization of contractile forces at the migrating front, enabled by higher frictional forces arising from simultaneous compressive loading of parallel fiber-substrate connections. We also model ‘haptotaxis’ to show that increasing ligand connectivity (but not continuity) increases migration efficiency. According to our model, increased rate of front stabilization via higher resistance to substrate deformation is sufficient to capture ‘durotaxis’. Thus, our findings reveal a new paradigm wherein the rate of leading-edge stabilization determines the efficiency of supracellular collective cell migration.
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Kim, Seul-Ki, So Dam Jang, Hyunho Kim, Seok Chung, Jong Kook Park y Hyo-Jeong Kuh. "Phenotypic Heterogeneity and Plasticity of Cancer Cell Migration in a Pancreatic Tumor Three-Dimensional Culture Model". Cancers 12, n.º 5 (21 de mayo de 2020): 1305. http://dx.doi.org/10.3390/cancers12051305.
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Invasive cancer cell migration is a key feature of metastatic human pancreatic ductal adenocarcinoma (PDAC), yet the underlying mechanisms remain poorly understood. Here, we investigated modes of cancer cell invasion using two pancreatic cancer cell lines with differential epithelial–mesenchymal status, PANC-1 and BxPC-3, under 3D culture conditions. Multicellular tumor spheroids (TSs) were grown in a collagen matrix co-cultured with pancreatic stellate cells (PSCs) using microchannel chips. PANC-1 cells showed individual migration from TSs via invadopodium formation. BxPC-3 cells showed plasticity between collective and individual migration in either mesenchymal mode, with filopodium-like protrusions, or blebby amoeboid mode. These two cell lines showed significantly different patterns of extracellular matrix (ECM) remodeling, with MMP-dependent degradation in a limited area of ECM around invadopodia for PANC-1 cells, or MMP-independent extensive deformation of ECM for BxPC-3 cells. Cancer cell migration out of the collagen channel significantly increased by PSCs and directional cancer cell migration was mediated by fibronectin deposited by PSCs. Our results highlight the phenotypic heterogeneity and plasticity of PDAC cell migration and ECM remodeling under 3D culture conditions. This 3D co-culture model of pancreatic cancer cells and PSCs offers a useful tool for studying cancer cell migration and ECM remodeling to identify and develop potential molecular targets and anti-cancer agents against human PDAC.
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Zhao, Lijiao, Qiuting Shu, Hui Sun, Yunlong Ma, Dandan Kang, Yating Zhao, Jing Lu, Pei Gong, Fan Yang y Fang Wan. "1′H-Indole-3′-Carbonyl-Thiazole-4-Carboxylic Acid Methyl Ester Blocked Human Glioma Cell Invasion via Aryl Hydrocarbon Receptor’s Regulation of Cytoskeletal Contraction". BioMed Research International 2020 (5 de octubre de 2020): 1–14. http://dx.doi.org/10.1155/2020/2616930.
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Blocking glioma cell invasion has been challenging due to cancer cells that can swiftly switch their migration mode, and agents that can block more than one migration mode are sought after. We found that small molecule 2-(1H-indole-3-carbonyl)-thiazole-4-carboxylic acid methyl ester (ITE), an endogenous aryl hydrocarbon receptor (AHR) agonist, can block more than one mode of glioma cell migration, based on cultured cell behavior captured by videos. Data from wound-healing assays and mouse xenograft glioma models corroborated ITE’s migration-inhibiting effects while knocking down AHR by siRNA abolished these effects. To identify genes that mediated ITE-AHR’s effect, we first collected gene expression changes upon ITE treatment by RNA-seq, then compared them against literature reported migration-related genes in glioma and that were potentially regulated by AHR. MYH9, a component of nonmuscle myosin IIA (NMIIA), was confirmed to be reduced by ITE treatment. When MYH9 was overexpressed in the glioma cells, a good correlation was observed between the expression level and the cell migration ability, determined by wound-healing assay. Correspondingly, overexpression of MYH9 abrogated ITE’s migration-inhibiting effects, indicating that ITE-AHR inhibited cell migration via inhibiting MYH9 expression. MYH9 is essential for cell migration in 3D confined space and not a discovered target of AHR; the fact that ITE affects MYH9 via AHR opens a new research and development avenue.
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Vérollet, Christel, Shanti Souriant, Emilie Bonnaud, Paul Jolicoeur, Brigitte Raynaud-Messina, Cassandre Kinnaer, Isabelle Fourquaux et al. "HIV-1 reprograms the migration of macrophages". Blood 125, n.º 10 (5 de marzo de 2015): 1611–22. http://dx.doi.org/10.1182/blood-2014-08-596775.
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Key PointsHIV-1 Nef reprograms human macrophage migration favoring the mesenchymal mode, which translates in vivo to macrophage tissue accumulation. Nef enhances mesenchymal migration by influencing podosome organization and function via the phagocyte-specific kinase Hck and WASP.
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Dekel, Avishai, Nir Mandelker, Frederic Bournaud, Daniel Ceverino, Yicheng Guo y Joel Primack. "Clump survival and migration in VDI galaxies: an analytical model versus simulations and observations". Monthly Notices of the Royal Astronomical Society 511, n.º 1 (14 de enero de 2022): 316–40. http://dx.doi.org/10.1093/mnras/stab3810.
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ABSTRACT We address the nature of the giant clumps in high-z galaxies that undergo violent disc instability, distinguishing between long-lived and short-lived clumps. We study the evolution of long-lived clumps during migration through the disc via an analytical model tested by simulations and confront theory with CANDELS-HST observations. The clump ‘bathtub’ model, which considers gas and stellar gain and loss, involves four parameters: the accretion efficiency α, the star formation rate (SFR) efficiency ϵd, and the outflow mass-loading factors for gas and stars, η and ηs. The corresponding time-scales are comparable to the migration time, two-three orbital times. The accretion-rate dependence on clump mass, gas, and stars, allows an analytical solution involving exponential growing and decaying modes. For the fiducial parameter values there is a main evolution phase where the SFR and gas mass are constant and the stellar mass is rising linearly with time. This makes the inverse specific SFR an observable proxy for clump age. When η or ϵd are high, or α is low, the decaying mode induces a decline of SFR and gas mass till the migration ends. Later, the masses and SFR approach an hypothetical exponential growth with a constant specific SFR. The model matches simulations with different, moderate feedbacks, both in isolated and cosmological settings. The observed clumps agree with our predictions, indicating that the massive clumps are long-lived and migrating. A challenge is to model feedback that is non-disruptive in massive clumps but suppresses SFR to match the galactic stellar-to-halo mass ratio.
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Filippi, Marie-Dominique. "Neutrophil transendothelial migration: updates and new perspectives". Blood 133, n.º 20 (16 de mayo de 2019): 2149–58. http://dx.doi.org/10.1182/blood-2018-12-844605.
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Abstract Neutrophils represent the first line of cellular defense against invading microorganism by rapidly moving across the blood–endothelial cell (EC) barrier and exerting effector cell functions. The neutrophil recruitment cascade to inflamed tissues involves elements of neutrophil rolling, firm adhesion, and crawling onto the EC surface before extravasating by breaching the EC barrier. The interaction between neutrophils and ECs occurs via various adhesive modules and is a critical event determining the mode of neutrophil transmigration, either at the EC junction (paracellular) or directly through the EC body (transcellular). Once thought to be a homogenous entity, new evidence clearly points to the plasticity of neutrophil functions. This review will focus on recent advances in our understanding of the mechanism of the neutrophil transmigration process. It will discuss how neutrophil–EC interactions and the subsequent mode of diapedesis, junctional or nonjunctional, can be context dependent and how this plasticity may be exploited clinically.
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Amereh, Meitham, Henning Struchtrup y Ben Nadler. "Mathematical Modeling of Spherical Shell-Type Pattern of Tumor Invasion". Symmetry 15, n.º 2 (19 de enero de 2023): 283. http://dx.doi.org/10.3390/sym15020283.
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Cancer cell migration, as the principal element of tumor invasion, involves different cellular mechanisms. Various modes of cell migration including single and collective motions contribute to the invasion patterns. The competition between adhesive cell–cell and cell–matrix forces is a key factor that determines such patterns. In this paper, we study a distinct shell-type mode of tumor invasion observed in brain and breast tumors. In this mode, cells at the outer layer of the tumor collectively move away from the core and form a shell-type shape. Both the core and the shell sustain a sharp interface between cells and the surrounding matrix. To model the preserved interface, we adopted a Cahn–Hilliard-type free energy relation with the contribution of the interfacial stress. This nonconvex form of free energy allows for cells to remain together and preserve the tumor core via adhesive cell–cell forces while separating the core from the surrounding matrix across a continuous sharp interface. In addition, the motion of the shell was modeled using the chemotactic migration of cells in response to the gradient of nutrients. The associated fluxes of cells were implemented in a general form of balance law. A non-Michaelis–Menten kinetics model was adopted for the proliferation rate of cells. The flux of nutrients was also modeled using a simple diffusion equation. The comparison between the model predictions and experimental observations indicates the ability of the model to manifest the salient features of the invasion pattern.
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Park, Changhyun. "Market entry strategies in a high-tech successive generations market: a case study of three semiconductor firms with different entry modes". Journal of Business & Industrial Marketing 35, n.º 11 (1 de abril de 2020): 1751–66. http://dx.doi.org/10.1108/jbim-08-2019-0354.
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Purpose The purpose of this study is to explore market entry strategies in a high-tech successive generations (HTSGs) market, by investigating entry mode via entry timing and path differentiation and the performance outcomes of entry mode. Design/methodology/approach The methodology of building a theory from a longitudinal case study is adopted by using useful cases in a HTSGs market after constructing an integrated research framework to explore market entry mode. Different entry modes were investigated by studying entry timing and migration path of three firms’ case in logic semiconductor market. In addition, performance outcomes of different entry modes were measured and correlated with each other. Findings The results identified three major entry modes suitable for a HTSGs market. The three firms differentiated their entry modes by exploiting different entry timings from the earliest to the last and different migration paths including switching, leapfrogging and new entrance path to enter a market. First mover advantage also exists in a HTSGs market, and it was found uniquely that the financial performance denoted by entry mode outcomes was correlated with technological knowledge. Research limitations/implications This study extends the theory of extant entry strategy from general consumer or industrial market to HTSGs market, in which intense competition exits and technological innovation is important. Moreover, this study verified that the causality between early entry and positive performance was also effective in HTSGs market with a shorter duration of early entry advantage. Practical implications This study has managerial implications for firms to establish market entry strategy in HTSGs market and other markets. To become a product leader, a fast follower or a late follower, firms can differentiate their entry mode by adjusting the entry timing and migration path in the context of market and technology. Originality/value This study examined market entry strategies suitable for HTSGs market based on its unique characteristics and extended relevant theory into HTSGs market. Further, an integrated research framework, which explores the market entry mode, was constructed to facilitate further exploration of entry mode into other markets.
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Maheshwari, Gargi, H. Steven Wiley y Douglas A. Lauffenburger. "Autocrine epidermal growth factor signaling stimulates directionally persistent mammary epithelial cell migration". Journal of Cell Biology 155, n.º 7 (24 de diciembre de 2001): 1123–28. http://dx.doi.org/10.1083/jcb.200109060.
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Cell responses to soluble regulatory factors may be strongly influenced by the mode of presentation of the factor, as in matrix-bound versus diffusible modes. The possibly diverse effect of presenting a growth factor in autocrine as opposed to exogenous (or paracrine) mode is an especially important issue in cell biology. We demonstrate here that migration behavior of human mammary epithelial cells in response to stimulation by epidermal growth factor (EGF) is qualitatively different for EGF presented in exogenous (paracrine), autocrine, and intracrine modes. When EGF is added as an exogenous factor to the medium of cells that express EGF receptor (EGFR) but not EGF, cell migration speed increases while directional persistence decreases. When these EGFR-expressing cells are made to also express via retroviral transfection EGF in protease-cleaveable transmembrane form on the plasma membrane, migration speed similarly increases, but directional persistence increases as well. Addition of exogenous EGF to these cells abrogates their enhanced directional persistence, reducing their directionality to a level similar to wild-type cells. If the EGFR-expressing cells are instead transduced with a gene encoding EGF in a soluble form, migration speed and directional persistence were unaffected. Thus, autocrine presentation of EGF at the plasma membrane in a protease-cleavable form provides these cells with an enhanced ability to migrate persistently in a given direction, consistent with their increased capability for organizing into gland-like structures. In contrast, an exogenous/paracrine mode of EGF presentation generates a “scattering” response by the cells. These findings emphasize the functional importance of spatial restriction of EGFR signaling, and suggest critical implications for growth factor–based therapeutic treatments.
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Kistnareddy, Ashwiny O. "Elsewhere Home: Hospitality, Affect, and Language in Ying Chen’s Lettres Chinoises and Kim Thúy’s Vi". Quebec Studies 71, n.º 1 (1 de junio de 2021): 91–110. http://dx.doi.org/10.3828/qs.2021.8.
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Though Canada’s Multiculturalism Act (1971) enables migrants to enter the country and keep their values and cultures, in practice this can be a difficult process. This essay focuses on two narratives written by a Chinese Canadian immigrant, Ying Chen’s Lettres chinoises (1993), and a Vietnamese Québécois refugee, Kim Thúy’s Vi (2016), to highlight the ways in which immigrating into a new country can be a highly affective experience. Drawing on Jacques Derrida’s notion of hospitality, this essay examines the ways in which each writer foregrounds the issues faced by migrants and refugees as they negotiate life in a new society. The emotional and physical experience of being a stranger joining a host society are concomitant and equally problematic. Sara Ahmed’s work is equally significant as it focuses on strangers’ embodied experiences of migration in a host society. Ultimately, this essay examines migration as a transformative experience for protagonists as they come to terms with a new life in Québec. La loi du Multiculturalisme instaurée au Canada en 1971 permet aux migrants de maintenir leurs valeurs et leur mode de vie d’avant le processus migratoire. Or, en pratique, ceci n’est pas toujours vécu sans heurts. Dans la présente étude, nous aborderons deux récits migratoires: le roman Les lettres chinoises (1993) de la Sino-Canadienne, Ying Chen, et Vi (2016) de la Québécoise d’origine vietnamienne, Kim Thúy, afin de mettre en relief la notion de l’immigration comme une expérience affective. En puisant dans les théories de Jacques Derrida portant sur l’hospitalité, nous discuterons la manière dont chacune de ces écrivaines traite des problèmes auxquels font face leurs protagonistes immigrants dans une nouvelle société. De plus, les aspects physiques et émotionnels qu’engendrent l’aliénation demeurent cruciaux et ainsi, nous nous tournerons vers les théories de Sara Ahmed afin de mettre en évidence les perspectives affectives et corporelles de l’immigration lorsque immigrés et réfugiés tentent de s’adapter à leur nouvelle vie au Québec.
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Alfonso, Liudmila Morales y Liosday Landaburo Sánchez. "Migrantes y vida pública en Cuba". Regions and Cohesion 7, n.º 3 (1 de diciembre de 2017): 8–29. http://dx.doi.org/10.3167/reco.2017.070303.
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*Full article is in SpanishEnglish abstract:The article analyzes how the participation of migrants in Cuban public life has been reconfi gured, starting with the process of updating the economic, political and social model that began in 2008. This group, which had been excluded from national public life through an intersection of offi cial policies and discourses—which supported the viewpoint of migration without return, due to political causes, and an “us vs. them” opposition—now benefi ts from a Cuba that is more open to the world and consistent with transnational migration. Although the road to full citizenship continues to be full of obstacles, there are new opportunities for participation in public life, which the article measures from the integration of Cubans residing in Ecuador in the formal and informal economies to their maintenance of a migratory status in Cuba and the fl ow of information and communication with their native country.Spanish abstract:El artículo analiza cómo se reconfi gura la participación de los migrantes en la vida pública cubana, a partir del proceso de actualización del modelo económico, político y social que inició en 2008. Este grupo, que había sido excluido de la vida pública nacional por una conjunción entre políticas y discursos ofi ciales —que sustentó el imaginario de una migración sin retorno, por causas políticas, y de una oposición nosotros/ ellos— se benefi cia de una Cuba más abierta al mundo y consecuente con la migración transnacional. Aunque el camino hacia una ciudadanía plena continúe lleno de obstáculos, existen nuevas oportunidades de participación en la vida pública, que el artículo mide desde la inserción de cubanos residentes en Ecuador en la economía, formal e informal; el mantenimiento de un status migratorio en Cuba y el fl ujo de información y comunicación con su país natal.French abstract:L’article analyse la façon dont la participation des migrants à la vie publique cubaine est reconfi gurée, en commençant par la mise à jour du modèle économique, politique et social qui a débuté en 2008. Ce groupe, exclu de la vie publique nationale conjointement par les politiques et discours offi ciels - qui ont soutenu l’imaginaire d’une migration sans retour, en raison de causes politiques et d’une opposition nous / eux - bénéfi cie d’un Cuba plus ouvert au monde et compatible avec les migrations transnationales. Et bien que le chemin vers la pleine citoyenneté continue d’être semé d’obstacles, il existe de nouvelles possibilités de participation à la vie publique que l’article met en évidence, depuis l’insertion des Cubains résidant en Équateur dans l’économie, formelle et informelle ; le maintien d’un statut migratoire à Cuba et le fl ux d’informations et de communication avec leur pays natal.
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Krull, C. E., A. Collazo, S. E. Fraser y M. Bronner-Fraser. "Segmental migration of trunk neural crest: time-lapse analysis reveals a role for PNA-binding molecules". Development 121, n.º 11 (1 de noviembre de 1995): 3733–43. http://dx.doi.org/10.1242/dev.121.11.3733.
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Trunk neural crest cells migrate through the somites in a striking segmental fashion, entering the rostral but not caudal sclerotome, via cues intrinsic to the somites. Attempts to define the molecular bases of these cues have been hampered by the lack of an accessible assay system. To examine trunk neural crest migration over time and to perturb candidate guiding molecules, we have developed a novel explant preparation. Here, we demonstrate that trunk regions of the chicken embryo, placed in explant culture, continue to develop apparently normally for 2 days. Neural crest cells, recognized by prelabeling with DiI or by poststaining with the HNK-1 antibody, migrate in the somites of the explants in their typical segmental pattern. Furthermore, this paradigm allows us to follow trunk neural crest migration in situ for the first time using low-light-level videomicroscopy. The trajectories of individual neural crest cells were often complex, with cells migrating in an episodic mode encompassing forward, backward and lateral movements. Frequently, neural crest cells migrated in close-knit groups of 2–4 cells, moving at mean rates of migration of 10–14 microns/hour. Treatment of the explants with the lectin peanut agglutinin (PNA) both slowed the rate and altered the pattern of neural crest migration. Neural crest cells entered both the rostral and caudal halves of the sclerotome with mean rates of migration ranging from 6 to 13 microns/hour. These results suggest that peanut agglutinin-binding molecules are required for the segmental patterning of trunk neural crest migration. Because this approach permits neural crest migration to be both observed and perturbed, it offers the promise of more direct assays of the factors that influence neural crest development.
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Ding, Mingye, Daqin Chen, Zhongyi Wan, Yang Zhou, Jiasong Zhong, Junhua Xi y Zhenguo Ji. "Achieving efficient Tb3+ dual-mode luminescence via Gd-sublattice-mediated energy migration in a NaGdF4 core–shell nanoarchitecture". Journal of Materials Chemistry C 3, n.º 21 (2015): 5372–76. http://dx.doi.org/10.1039/c5tc00881f.
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Efficient dual-mode luminescence from identical Tb3+ in single NaGdF4 nanoparticles has been successfully realized for the first time with the help of Gd-sublattice-mediated energy migration and core–shell engineering techniques.
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Rindlisbacher, Stefan y Olivier Hanse. "La « Nouvelle Droite » écologique au XXI e siècle : post-croissance, biorégionalisme et « réforme de la vie »". Allemagne d'aujourd'hui N° 245, n.º 3 (28 de septiembre de 2023): 117–28. http://dx.doi.org/10.3917/all.245.0117.
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Depuis 2008, la « Nouvelle Droite » autoproclamée autour du publiciste Götz Kubitschek tente de récupérer pour l’extrême droite la thématique de la protection de la nature et de l’environnement. Cet article analyse comment la stratégie mise en œuvre par la « Nouvelle Droite » d’un déplacement successif de discours a été utilisée en vue de réinterpréter la protection de la nature et de l’environnement comme une préoccupation conservatrice, de remettre en question la légitimité des partis et des mouvements de gauche en tant que porteurs de la politique écologique, et de faire accepter à la place la « Nouvelle Droite » comme mouvement écologique du XXI e siècle. La « Nouvelle Droite » visait à diffamer les stratégies de protection du climat de la gauche en les présentant comme des mesures technicisées, aliénées par la nature, tandis que ses propres avancées étaient présentées comme une approche « holistique », englobant l’homme, son environnement et la culture. En s’appuyant sur le fonds historique des écologistes de droite, ils ont placé la régulation de la population, des individus et de leurs corps au centre de leurs efforts. L’article montre d’une part comment la « Nouvelle Droite » a adapté les approches critiques du capitalisme et de la consommation du mouvement post-croissance et du biorégionalisme pour présenter la croissance démographique et la migration globale comme des problèmes environnementaux et pour revendiquer une société culturellement homogène. D’autre part, nous verrons comment ils ont propagé les pratiques sanitaires et corporelles du mouvement de « Lebensreform » [« réforme de la vie »], telles que l’agriculture biologique, la réforme alimentaire et le végétarisme, afin de mettre concrètement en œuvre un mode de vie plus naturel et à consommation réduite.
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Klaassen, M. "Metabolic constraints on long-distance migration in birds". Journal of Experimental Biology 199, n.º 1 (1 de enero de 1996): 57–64. http://dx.doi.org/10.1242/jeb.199.1.57.
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The flight range of migrating birds depends crucially on the amount of fuel stored by the bird prior to migration or taken up en route at stop-over sites. However, an increase in body mass is associated with an increase in energetic costs, counteracting the benefit of fuel stores. Water imbalance, occurring when water loss exceeds metabolic water production, may constitute another less well recognised problem limiting flight range. The main route of water loss during flight is via the lungs; the rate of loss depends on ambient temperature, relative humidity and ventilatory flow and increases with altitude. Metabolite production results in an increased plasma osmolality, also endangering the proper functioning of the organism during flight. Energetic constraints and water-balance problems may interact in determining several aspects of flight behaviour, such as altitude of flight, mode of flight, lap distance and stop-over duration. To circumvent energetic and water-balance problems, a bird could migrate in short hops instead of long leaps if crossing of large ecological barriers can be avoided. However, although necessitating larger fuel stores and being more expensive, migration by long leaps may sometimes be faster than by short hops. Time constraints are also an important factor in explaining why soaring, which conserves energy and water, occurs exclusively in very large species: small birds can soar at low speeds only. Good navigational skills involving accurate orientation and assessment of altitude and air and ground speed assist in avoiding physiological stress during migration.
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Zhu, Qi, Jianli Shao y Pei Wang. "The Interaction between He Bubble and Migrating Grain Boundary Induced by Shear Loading". Metals 12, n.º 12 (24 de noviembre de 2022): 2012. http://dx.doi.org/10.3390/met12122012.
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This work reveals the interaction mechanism between He bubble and grain boundary (GB) in bicrystal copper under shear loading via molecular dynamics simulations. The influences of He/vacancy ratio RHe/V, temperature T0, and bubble diameter D0 on the interaction mechanism are clarified. Specifically, two interaction modes, i.e., the GB traverses or is pinned on He bubble, are observed by changing the initial RHe/V, T0, and D0. As RHe/V increases, the influence of He bubble on GB migration shows a decrease–increase trend. Different He bubble evolutions are demonstrated by comparing their shapes, pressure, and volume. In the cases of low RHe/V, the medium temperatures (10–300 K) are found to accelerate the GB migration, but higher temperatures (600–900 K) will lead to the change in interaction mode and deteriorate the interaction process. Furthermore, a more noticeable bubble-drag effect on GB migration is observed in the samples with larger He bubble.
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Deleixhe, Martin. "Michael Walzer à l’épreuve de la Commission von der Leyen". Raisons politiques N° 94, n.º 2 (6 de junio de 2024): 39–60. http://dx.doi.org/10.3917/rai.094.0039.
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Lorsqu’en 2019, Ursula Von der Leyen dévoila au public la répartition des portefeuilles entre les différents commissaires européens, l’intitulé de l’un d’entre eux déclencha une vive controverse. Margaritas Schinas, le Vice-Président de la Commission, se voyait attribuer un éventail de compétences qui allaient de la sécurité intérieure à l’éducation en passant par la migration, regroupées sous l’appellation « Protection de notre mode de vie européen ». Dénoncée comme xénophobe par certains eurodéputés, cette dénomination a été défendue par la Commission comme la recherche d’un consensus normatif minimal garantissant la stabilité du projet d’intégration politique. Cet article suggère tout d’abord que la justification de la dénomination de ce portefeuille et de sa feuille de route politique ressemble à s’y méprendre aux arguments sur la justice migratoire développés par le philosophe Michael Walzer dans le second chapitre de Sphères de justice . Pour ce faire, il récapitule les différentes étapes de la controverse au cours desquelles s’est construit et affiné la parole publique de la Commission. Il confronte ensuite la théorie de la justice migratoire de Walzer au discours de légitimation des exclusions de migrants par la Commission pour mettre en évidence un impensé de l’approche walzérienne : le paradoxe de l’identité libérale. Dans un troisième temps, il interroge la légitimation de pratiques d’exclusion au sein d’une communauté politique post-nationale qui fait de principes universalistes le socle de son identité collective.
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Liskova, Veronika, Sona Hudecova, Lubomira Lencesova, Filippo Iuliano, Marta Sirova, Karol Ondrias, Silvia Pastorekova y Olga Krizanova. "Type 1 Sodium Calcium Exchanger Forms a Complex with Carbonic Anhydrase IX and Via Reverse Mode Activity Contributes to pH Control in Hypoxic Tumors". Cancers 11, n.º 8 (9 de agosto de 2019): 1139. http://dx.doi.org/10.3390/cancers11081139.
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Hypoxia and acidosis are among the key microenvironmental factors that contribute to cancer progression. We have explored a possibility that the type 1Na+/Ca2+ exchanger (NCX1) is involved in pH control in hypoxic tumors. We focused on changes in intracellular pH, co-localization of NCX1, carbonic anhydrase IX (CA IX), and sodium proton exchanger type 1 (NHE1) by proximity ligation assay, immunoprecipitation, spheroid formation assay and migration of cells due to treatment with KB-R7943, a selective inhibitor of the reverse-mode NCX1. In cancer cells exposed to hypoxia, reverse-mode NCX1 forms a membrane complex primarily with CA IX and also with NHE1. NCX1/CA IX/NHE1 assembly operates as a metabolon with a potent ability to extrude protons to the extracellular space and thereby facilitate acidosis. KB-R7943 prevents formation of this metabolon and reduces cell migration. Thus, we have shown that in hypoxic cancer cells, NCX1 operates in a reverse mode and participates in pH regulation in hypoxic tumors via cooperation with CAIX and NHE1.
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Serem, Jeptoo N., Stanley N. Wambugu, John K. Mwonjoria y Marion B. Warigia. "Anti-inflammatory Effects of Carissa spiranum Mediated via Attenuation of Leucocyte Migration". Journal of Phytopharmacology 13, n.º 3 (1 de junio de 2024): 230–34. http://dx.doi.org/10.31254/phyto.2024.13306.
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Inflammation is a physiological process vital for pathogen elimination and tissue repair. However, left untreated, it can cause undesirable effects. There are several methods for management of the condition, including traditional remedies from plant sources that are thought to have few deleterious effects on the body, as is the case with steroids and NSAIDs. One of the plants widely used is Carissa spiranum, though little has been done to determine the effects of purified extracts on the condition and their mode of action. The present study investigated the effects of purified plant extract and its flavonoid-rich fraction on inflammation and leukocyte migration in mice. Formalin and carrageenan were used as the phlogistic substances in inflammation induction and leukocyte migration, respectively. While diclofenac sodium and dexamethasone were used as standard drugs. The diameter of the paw edema induced in the left hind paw of mice was measured and quantified as the edema developed in mice, while the number of leucocytes in peritoneal fluid lavage after pretreatment with carrageenan and determined with improved Neubauer chamber was used in the determination of the extent of leucocyte migration. The extracts exhibited a significant (p < 0.05) reduction in paw edema diameter and delayed leucocyte migration compared to the vehicle. These observations suggest that the plant extracts may contain compounds that exert their anti-inflammatory effects via attenuation of leucocyte migration.
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Takashina, Nao. "On the spillover effect and optimal size of marine reserves for sustainable fishing yields". PeerJ 8 (25 de agosto de 2020): e9798. http://dx.doi.org/10.7717/peerj.9798.
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Marine reserves are an essential component of modern fishery management. Marine reserves, which represent a management tradeoff between harvesting and conservation, are fundamental to maintenance of fisheries. Finding optimal reserve sizes that improve fishing yields is not only of theoretical interest, but also of practical importance to facilitate decision making. Also, since the migratory behavior of some species influences the spillover effect of a marine reserve, this is a key consideration when assessing performance of marine reserves. The relationship between optimal reserve size and migration rate/mode has not been well studied, but it is fundamental to management success. Here, I investigate optimal reserve size and its management outcome with different levels of spillover via a simple two-patch mathematical model. In this model, one patch is open to fishing, and the other is closed. The two-patch model is aggregated by single-population dynamics when the migration rate is sufficiently larger than the growth rate of a target species. At this limit, I show that an optimal reserve size exists when pre-reserve fishing occurs at fishing mortality larger than fMSY, the fishing mortality at the maximum sustainable yield (MSY). Also, the fishing yield at an optimal reserve size becomes as large as MSY at the limit. Numerical simulations at various migration rates between the two patches suggest that the maximum harvest under management with a marine reserve is achieved at this limit. This contrasts with the conservation benefit which is maximized at an intermediate migration rate. Numerical simulations show that the above-mentioned condition for an optimal reserve size to exist derived from the aggregated model is necessary when the migration rate is not sufficiently large, and that a moderate migration rate is further necessary for an optimal reserve size to exist. However, high fishing mortality reduces this requirement.
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Kocan, Richard M. "Transmission models for the fish pathogen Ichthyophonus: synthesis of field observations and empirical studies". Canadian Journal of Fisheries and Aquatic Sciences 76, n.º 4 (abril de 2019): 636–42. http://dx.doi.org/10.1139/cjfas-2018-0166.
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Empirical studies have demonstrated that Ichthyophonus is transmitted among piscivores via consumption of infected prey; however, this unidirectional mode of transmission from small to large fish cannot sustain Ichthyophonus within a population. To circumvent this problem, Ichthyophonus evolved an infective waterborne cell that has been shown to infect both fresh- and saltwater fish. Successful transmission of Ichthyophonus via a waterborne stage is linked to the proximity of infected and susceptible individuals, a condition met when the two groups occupy the same habitat. It is posited that this occurs during annual inshore migrations when herring (Clupea spp.) enter areas occupied by infected demersal predators. A plausible transmission scenario is that during inshore excursions, planktivores are exposed to infective waterborne cells shed by demersal piscivores. Once planktivores are infected, the parasite is recycled when consumed by predators. This model is supported by reports of ichthyophoniasis increasing in herring populations at the time of inshore migration. The possible role of an intermediate host for Ichthyophonus, as well as evidence for a free-living stage in its life cycle, is presented.
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Liu, Linsheng, Zhen Deng, Guipeng Liu, Chongtao Kong, Hao Du, Ruolin Chen, Jianfeng Yan et al. "Low-Temperature Migration-Enhanced Epitaxial Growth of High-Quality (InAs)4(GaAs)3/Be-Doped InAlAs Quantum Wells for THz Applications". Crystals 14, n.º 5 (29 de abril de 2024): 421. http://dx.doi.org/10.3390/cryst14050421.
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This investigation explores the structural and electronic properties of low-temperature-grown (InAs)4(GaAs)3/Be-doped InAlAs and InGaAs/Be-doped InAlAs multiple quantum wells (MQWs), utilizing migration-enhanced epitaxy (MEE) and conventional molecular beam epitaxy (MBE) growth mode. Through comprehensive characterization methods including transmission electron microscopy (TEM), Raman spectroscopy, atomic force microscopy (AFM), pump–probe transient reflectivity, and Hall effect measurements, the study reveals significant distinctions between the two types of MQWs. The (InAs)4(GaAs)3/Be-doped InAlAs MQWs grown via the MEE mode exhibit enhanced periodicity and interface quality over the InGaAs/Be-InAlAs MQWs grown through the conventional molecule beam epitaxy (MBE) mode, as evidenced by TEM. The AFM results indicate lower surface roughness for the (InAs)4(GaAs)3/Be-doped InAlAs MQWs by using the MEE mode. Raman spectroscopy reveals weaker disorder-activated modes in the (InAs)4(GaAs)3/Be-doped InAlAs MQWs by using the MEE mode. This originates from utilizing the (InAs)4(GaAs)3 short period superlattices rather than InGaAs, which suppresses the arbitrary distribution of Ga and In atoms during the InGaAs growth. Furthermore, pump–probe transient reflectivity measurements show shorter carrier lifetimes in the (InAs)4(GaAs)3/Be-doped InAlAs MQWs, attributed to a higher density of antisite defects. It is noteworthy that room temperature Hall measurements imply that the mobility of (InAs)4(GaAs)3/Be-doped InAlAs MQWs grown at a low temperature of 250 °C via the MEE mode is superior to that of InGaAs/Be-doped InAlAs MQWs grown in the conventional MBE growth mode, reaching 2230 cm2/V.s. The reason for the higher mobility of (InAs)4(GaAs)3/Be-doped InAlAs MQWs is that this short-period superlattice structure can effectively suppress alloy scattering caused by the arbitrary distribution of In and Ga atoms during the growth process of the InGaAs ternary alloy. These results exhibit the promise of the MEE growth approach for growing high-performance MQWs for advanced optoelectronic applications, notably for high-speed optoelectronic devices like THz photoconductive antennas.
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Ferguson, Kristin M. "Responding to children’s street work with alternative income-generation strategies". International Social Work 49, n.º 6 (noviembre de 2006): 705–17. http://dx.doi.org/10.1177/0020872806069076.
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English Empirical precedents indicate the positive impact of income-generating initiatives on the lives of vulnerable populations around the world. However, there is limited research on such interventions with street-working children. A social development model is proposed for street-working children and their parents as a means to curb child street migration. French L'expérience confirme l'impact positif des initiatives de production de revenus sur la vie des populations vulnérables dans le monde. Toutefois, il existe peu de recherche concernant de telles initiatives auprès des enfants qui travaillent dans la rue. Cette recherche propose un modèle de développement social à l'intention des enfants qui font du travail de rue et de leurs parents afin de faire fléchir la migration des enfants vers la rue. Spanish Precedentes empíricos indican que las iniciativas que generan ingresos tienen un impacto positivo en las vidas de poblaciones vulnerables de todo el mundo. Sin embargo se ha hecho poca investigación sobre tales intervenciones con niños que trabajan en la calle. Se propone un modelo de desarrollo social para estos niños y sus padres, al objeto de disminuir la migración de niños a la calle.
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Tang, Sheau-Chung, Jiunn-Liang Ko, Chun-Te Lu, Pui-Ying Leong, Chu-Chyn Ou, Chih-Ting Hsu y Yu-Ping Hsiao. "Chloroquine alleviates the heat-induced to injure via autophagy and apoptosis mechanisms in skin cell and mouse models". PLOS ONE 17, n.º 8 (31 de agosto de 2022): e0272797. http://dx.doi.org/10.1371/journal.pone.0272797.
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Burns can cause cell death and irreversible tissue damage. We examined the pathway of human dermis fibroblasts cell death caused by skin burns and the roles of chloroquine in human skin keratinocytes HaCaT wound healing. Western blot assays were performed to assess expression of proteins associated with autophagy, apoptosis, and endoplasmic reticulum stress in skin cells following burns. Changes in apoptosis-related proteins were assessed using flow cytometry, and wound cell migration was examined using wound healing assays. The burn animal model was used to test whether chloroquine would promote wound healing. In human burned fibroblasts, expression of LC3B-II and Cleave-caspase-7 was increased, whereas expression of Beclin-1, p62, and Grp78 was decreased. Severe burn induced ER stress and ERK phosphorylation, but PD98059 or necrostatin-1 treatment cells did not affect expression of autophagy LC3B-II protein and can induce apoptosis. Even though added with TGF-β and FGF did not repair autophagy caused by burns. Suggesting that autophagy and apoptosis were involved in heat-injured mechanism. Recombinant Wnt3a protein can help restore expression of β-catenin which reduced following burns in keratinocytes. Wnt3a protein can promote migration of keratinocytes after burns. Interesting, chloroquine increased expression of LC3B-II protein and restored cell migration activity after 24 h of burns. Consistently, surgical dressing containing chloroquine promoted wound healing in a burn animal mode. Autophagy and Wnt/β-catenin is two signalling pathways that participate in cell repair and wound healing in human fibroblasts, keratinocytes. Surgical dressing containing chloroquine can recover wound healing in burned rats.
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Varsakelis, C. y M. V. Papalexandris. "Stability of wall bounded, shear flows of dense granular materials: the role of the Couette gap, the wall velocity and the initial concentration". Journal of Fluid Mechanics 791 (22 de febrero de 2016): 384–413. http://dx.doi.org/10.1017/jfm.2016.65.
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In this paper, the stability of a plane, unidirectional Couette flow of a dense granular material is investigated via the means of a normal mode stability analysis. Our studies are based on a continuum mechanical model for the flows of interest coupled with the constitutive expressions for the normal and the shear stresses of the granular material induced by the ${\it\mu}(I)$-rheology. According to our analysis, both the Couette gap and the wall velocity play a destabilizing role in the flows of interest as opposed to the initial concentration that acts as stabilizer. For sufficiently high Couette gaps and wall velocities, unstable modes are recovered. The predicted instability manifests itself through shear-induced dilatancy that, in turn, engenders particle migration and the formation of bulbs, similar to the ones that have been acquired through molecular dynamics simulations.
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Santelli, Emmanuelle. "Partir à Londres… pour favoriser l’insertion professionnelle en France". Enfances, Familles, Générations, n.º 19 (12 de marzo de 2014): 64–84. http://dx.doi.org/10.7202/1023771ar.
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Dans un contexte d’accroissement des migrations des Français vers Londres, cet article s’attache à comprendre les motivations de jeunes adultes français d’origine maghrébine qui entreprennent cette mobilité dans l’objectif de favoriser leur insertion professionnelle. Une partie de ces jeunes bénéficient en France d’un dispositif d’encouragement à la mobilité internationale. Initié par une mission locale qui accompagne ces jeunes tout au long de leur mobilité, ils sont accueillis par une structure française basée à Londres qui leur propose des annonces d’emploi et de logement. A partir de leur base de données, la première partie de l’article traite des caractéristiques des jeunes selon qu’ils partent dans le cadre d’un dispositif d’accompagnement à la mobilité, ou non. Les premiers subissent plus encore que les seconds une situation à l’égard de l’emploi marquée par la précarité. Ils ne se situent pas non plus au même stade de leur cycle de vie. Ensemble de résultats qui sont confortés et approfondis par l’analyse des entretiens biographiques réalisés avec des jeunes partis quelques mois à Londres. La seconde partie de l’article comporte trois sections reposant sur l’analyse du matériau qualitatif et permet d’aborder leurs motivations à partir, comment à travers cette expérience ils découvrent leur francité et un nouveau mode de vie. Procurant de nouvelles références, c’est tout le processus d’entrée dans la vie adulte qui s’en trouve affecté. Toutefois, cette mobilité est le plus souvent accomplie dans l’idée de favoriser leur insertion professionnelle en France. Loin d’engager une mobilité signe d’une prise de distance, elle marque au contraire leur souhait de partir « pour mieux revenir », car ils sont profondément attachés à leur région d’origine et aux liens familiaux.
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Pottapinjara, Vijay, M. S. Girishkumar, R. Murtugudde, K. Ashok y M. Ravichandran. "On the Relation between the Boreal Spring Position of the Atlantic Intertropical Convergence Zone and Atlantic Zonal Mode". Journal of Climate 32, n.º 15 (9 de julio de 2019): 4767–81. http://dx.doi.org/10.1175/jcli-d-18-0614.1.
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Abstract Previous studies have talked about the existence of a relation between the Atlantic meridional mode (AMM) and Atlantic zonal mode (AZM) via the meridional displacement of the intertropical convergence zone (ITCZ) in the Atlantic during boreal spring and the resulting cross-equatorial zonal winds. However, why the strong relation between the ITCZ (or AMM) and zonal winds does not translate into a strong relation between the ITCZ and AZM has not been explained. This question is addressed here, and it is found that there is a skewness in the relation between ITCZ and AZM: while a northward migration of ITCZ during spring in general leads to a cold AZM event in the ensuing summer, the southward migration of the ITCZ is less likely to lead to a warm event. This is contrary to what the previous studies imply. The skewness is attributed to the Atlantic seasonal cycle and to the strong seasonality of the AZM. All those cold AZM events preceded by a northward ITCZ movement during spring are found to strictly adhere to typical timings and evolution of the different Bjerknes feedback components involved. It is also observed that the causative mechanisms of warm events are more diverse than those of the cold events. These results can be expected to enhance our understanding of the AZM as well as that of chronic model biases and contribute to the predictability of the Indian summer monsoon through the links between the two as shown in our earlier studies.
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Blangy, Sylvie y Anna Deffner. "Impacts du développement minier sur les hommes et les caribous à Qamani’tuaq au Nunavut: approche participative". Études/Inuit/Studies 38, n.º 1-2 (25 de febrero de 2015): 239–65. http://dx.doi.org/10.7202/1028862ar.
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Au Canada, le développement minier pose de nombreux défis aux communautés autochtones qui y voient un véritable potentiel économique, mais aussi des risques pour leur mode de vie basé sur une économie mixte combinant économie salariale et activités de subsistance. Au Nunavut, la communauté de Qamani’tuaq (Baker Lake) se trouve confrontée aux impacts des activités de la mine d’or de Meadowbank et est actuellement en phase de négociations pour un deuxième projet minier, une mine d’uranium proposée par la compagnie Areva. Les connaissances encore fragmentaires des impacts miniers, surtout sur les plans social et culturel, permettent difficilement à la communauté de se positionner. Le bien-être des habitants ne dépend pas seulement d’un bien-être matériel mais aussi de l’accès au territoire et du maintien des activités de subsistance. Les résultats de notre étude, basée sur une approche participative, montrent que la mine de Meadowbank a déjà fortement affecté la communauté de Qamani’tuaq: exacerbation des problèmes sociaux, création de tensions familiales et accroissement des disparités salariales. Par ailleurs, les craintes quant aux impacts de nouvelles infrastructures, dont une deuxième route minière, sont nourries par l’expérience de la mine d’or en activité qui a des impacts majeurs sur l’environnement: retombée des poussières sur la végétation et déviation de la route de migration des caribous. Dans cet article, nous décrivons une nouvelle approche de recherche collaborative développée avec la communauté sur le long terme, lente, adaptée au rythme des événements miniers et reposant sur la participation d’assistantes de recherche inuit.
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Gupta, T. K. y A. C. Miller. "Improved stability of the ZnO varistor via donor and acceptor doping at the grain boundary". Journal of Materials Research 3, n.º 4 (agosto de 1988): 745–54. http://dx.doi.org/10.1557/jmr.1988.0745.
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The ZnO varistor degradation has been attributed to the field-assisted, temperature-activated diffusion of interstitial zinc in the depletion layer. To improve stability, one approach is to reduce the formation of interstitials, and then further, to prevent their migration through empty interstitial sites. Based on this concept, an amphoteric dopant, such as Na or K, has been incorporated in the ZnO varistor grain boundary wherein a dopant is substituted both in the lattice and in the interstitial sites. A grain boundary defect model has been developed for this dual mode of substitution, with the dopant acting as an acceptor at the lattice site and as a donor at the interstitial site. Under these conditions, and given a desired neutrality range, the concentration of zinc interstitial is indeed shown to be reduced and stability greatly improved. The experimental data presented here validate the grain boundary defect model presented in this and in an earlier paper [J. Mater. Sci. 20, 3487 (1985)].
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Caldwell, Kyle y John C. Berg. "Direct observation of nanoparticle migration in epoxy based fiber reinforced composites using fluorescence microscopy". Journal of Composite Materials 51, n.º 28 (17 de febrero de 2017): 3877–85. http://dx.doi.org/10.1177/0021998317694704.
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The preferential accumulation of nanoparticles at carbon fiber surfaces, induced by the addition of a thermoplastic “migrating agent” to an epoxy resin, was monitored via in situ fluorescence microscopy. (3-Glydidyloxypropyl)trimethoxysilane functionalized fluorescent silica nanoparticles (GFCSP) were synthesized by a modified Stöber method to track the spatiotemporal abundance of nanoparticles. Single carbon fibers were embedded in an uncured epoxy mixture consisting of tetraglycidyl-4,4-diaminodiphenylmethane and 4,4’-diamnodiphenyl sulfone, as well as thermoplastic migrating agent, poly(ether sulfone), and GFCSP. A heated microscope stage was used to monitor the fluorescence in the local vicinity of the fiber as the epoxy begins to cross-link and solidify upon heating. Our results show that the synthesized GFCSP accumulate at fiber surfaces only in the presence of poly(ether sulfone), as verified using scanning electron micrographs of Mode I fiber fracture surfaces.
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Zhang, Shen, Hui Dong, Lewis J. Rubin y Jason X. J. Yuan. "Upregulation of Na+/Ca2+ exchanger contributes to the enhanced Ca2+ entry in pulmonary artery smooth muscle cells from patients with idiopathic pulmonary arterial hypertension". American Journal of Physiology-Cell Physiology 292, n.º 6 (junio de 2007): C2297—C2305. http://dx.doi.org/10.1152/ajpcell.00383.2006.
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A rise in cytosolic Ca2+ concentration ([Ca2+]cyt) in pulmonary artery smooth muscle cells (PASMC) is a trigger for pulmonary vasoconstriction and a stimulus for PASMC proliferation and migration. Multiple mechanisms are involved in regulating [Ca2+]cyt in human PASMC. The resting [Ca2+]cyt and Ca2+ entry are both increased in PASMC from patients with idiopathic pulmonary arterial hypertension (IPAH), which is believed to be a critical mechanism for sustained pulmonary vasoconstriction and excessive pulmonary vascular remodeling in these patients. Here we report that protein expression of NCX1, an NCX family member of Na+/Ca2+ exchanger proteins is upregulated in PASMC from IPAH patients compared with PASMC from normal subjects and patients with other cardiopulmonary diseases. The Na+/Ca2+ exchanger operates in a forward (Ca2+ exit) and reverse (Ca2+ entry) mode. By activating the reverse mode of Na+/Ca2+ exchange, removal of extracellular Na+ caused a rapid increase in [Ca2+]cyt, which was significantly enhanced in IPAH PASMC compared with normal PASMC. Furthermore, passive depletion of intracellular Ca2+ stores using cyclopiazonic acid (10 μM) not only caused a rise in [Ca2+]cyt due to Ca2+ influx through store-operated Ca2+ channels but also mediated a rise in [Ca2+]cyt via the reverse mode of Na+/Ca2+ exchange. The upregulated NCX1 in IPAH PASMC led to an enhanced Ca2+ entry via the reverse mode of Na+/Ca2+ exchange, but did not accelerate Ca2+ extrusion via the forward mode of Na+/Ca2+ exchange. These observations indicate that the upregulated NCX1 and enhanced Ca2+ entry via the reverse mode of Na+/Ca2+ exchange are an additional mechanism responsible for the elevated [Ca2+]cyt in PASMC from IPAH patients.
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Zhang, Xiaoyu, Jianchun Fan, Fei Guo, Hailu Huang, Jun Xue, Xueliang Wu y Tian Li. "Effect of Kaempferol on the Biological Behavior of Human Colon Cancer via Regulating MMP1, MMP2, and MMP9". Journal of Oncology 2022 (13 de septiembre de 2022): 1–13. http://dx.doi.org/10.1155/2022/2841762.
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Kaempferol is a kind of flavonoid, which has a significant anticancer effect. MMPs were discovered with the function of cleaving the extracellular matrix. We utilized bioinformatics to analyze the association and bonding mode between the traditional Chinese medicine (TCM) monomer composition (i.e., kaempferol) and the target proteins. The purpose of our research was to verify the effect of kaempferol on the biological behavior of human colon cancer cells HCT116 and HT29 and the expression of matrix metalloproteinase (MMP) 1, 2, and 9 genes. We detected the changes in the biological behavior of colon cancer cells treated with kaempferol by CCK-8, wound healing assay, transwell migration/invasion assay, and flow cytometry. Meanwhile， we detected the expression difference of the target gene by qRT-PCR and western blot. Compared with the two control groups, the cell viability of the kaempferol group decreased, the rate of cell migration and the number of transmembrane cells in the kaempferol group decreased significantly, and the early apoptosis rate increased, the number of cells in the G1 phase increased and in the S phase decreased. The results of qRT-PCR and western blot showed that the expression of target genes MMP1, 2, and 9 in the kaempferol group was lower than that in the two control groups. Kaempferol can significantly inhibit the proliferation, invasion, and migration ability of colon cancer cells; induce their apoptosis; and block the cell cycle. Meanwhile, the expression of MMP1, 2, and 9 genes was downregulated, which verified the results of bioinformatic analysis.
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Chen, Jun, Zhiguang Duan, Yannan Liu, Rongzhan Fu y Chenhui Zhu. "Ginsenoside Rh4 Suppresses Metastasis of Esophageal Cancer and Expression of c-Myc via Targeting the Wnt/β-Catenin Signaling Pathway". Nutrients 14, n.º 15 (25 de julio de 2022): 3042. http://dx.doi.org/10.3390/nu14153042.
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The metastasis of esophageal squamous cell carcinoma (ESCC) is a leading cause of death worldwide, however, it has a poor prognosis. Ginsenoside Rh4 is a rare saponin that has been shown to have potential antitumor effectiveness in ESCC. However, the utility of Rh4 in ESCC metastasis and its undiscovered mode of action has not yet been explored. In this study, we found that Rh4 could inhibit ESCC metastasis by regulating the Wnt/β-catenin signaling pathway and the level of c-Myc, which is an important transcription factor in cancer. In in vitro experiments, Rh4 could inhibit the migration and invasion of ESCC cells without affecting cell viability. In in vivo experiments, Rh4 restrained ESCC metastasis to the lymph nodes and lungs via the suppression of epithelial-mesenchymal transition (EMT). The Wnt agonist HLY78 promoted EMT and migration of ESCC cells, whereas treatment of Rh4 can attenuate the promotion effect of HLY78. The siRNA knocking out c-Myc can also significantly reduce the expression of EMT-related marker proteins. This study illustrates a new concept for further research on the mechanism of Rh4 in ESCC.
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Becker, Bernhard P. y Holger Schüttrumpf. "An OpenMI module for the groundwater flow simulation programme Feflow". Journal of Hydroinformatics 13, n.º 1 (19 de marzo de 2010): 1–12. http://dx.doi.org/10.2166/hydro.2010.039.
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The OpenMI standard defines an interface that allows time-dependent models to exchange data at runtime. The migration of a flow simulation programme to OpenMI compliance usually requires changes in the source code or even a reorganisation of the programme sequence. Users of commercial flow simulation programmes depend on the software producer if they want to couple their models according to the OpenMI standard. We describe how we made the groundwater flow simulation programme Feflow OpenMI compliant without changing the source code: an OpenMI-compliant control application communicates with Feflow via remote procedure calls. A basic prerequisite for applying this method is an entry point into the flow simulation programme that allows to modify the model data during runtime and to implement the remote procedure calls. Feflow meets this requirement as it provides the interface manager (IFM). The mode of operation is explained with a simple test case including an inundation model and a Feflow groundwater model.
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Chen, Qiaoyu, Yongbin Jing, Jie Yin, Zheng Li, Wei Xiong, Ping Gong, Lu Zhang et al. "High Reflectivity and Thermal Conductivity Ag–Cu Multi-Material Structures Fabricated via Laser Powder Bed Fusion: Formation Mechanisms, Interfacial Characteristics, and Molten Pool Behavior". Micromachines 14, n.º 2 (31 de enero de 2023): 362. http://dx.doi.org/10.3390/mi14020362.
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Ag and Cu have different advantages and are widely used in key fields due to their typical highly electrical and thermal conductive (HETC) properties. Laser powder bed fusion (LPBF), an innovative technology for manufacturing metallic multi-material components with high accuracy, has expanded the application of Ag–Cu in emerging high-tech fields. In this study, the multi-material sandwich structures of Ag7.5Cu/Cu10Sn/Ag7.5Cu were printed using LPBF, and the formation mechanism, interface characteristics, and molten pool behavior of the Ag7.5Cu/Cu10Sn (A/C) and Cu10Sn/Ag7.5Cu (C/A) interfaces were studied to reveal the influence of different building strategies. At the A/C interface, pre-printed Ag7.5Cu promoted Marangoni turbulence at a relatively low energy density (EA/C = 125 J/mm3). Due to the recoil pressure, the molten pool at the A/C interface transformed from a stable keyhole mode to an unstable keyhole mode. These phenomena promoted the extensive migration of elements, forming a wider diffusion zone and reduced thermal cracking. At the C/A interface, the molten pool was rationed from the conduction mode with more pores to the transition mode with fewer defects due to the high energy density (EC/A = 187.5 J/mm3). This work offers a theoretical reference for the fabrication of HETC multi-material structures via LPBF under similar conditions.
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Ji, Yufan, Yuyang Song, Yiping Huang, Hao Zhu, Changhai Yue, Fujian Liu y Jing Zhao. "One-Step Synthesis of Ultrathin Zeolitic Imidazole Framework-8 (ZIF-8) Membrane on Unmodified Porous Support via Electrophoretic Deposition". Membranes 12, n.º 11 (28 de octubre de 2022): 1062. http://dx.doi.org/10.3390/membranes12111062.
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Metal–organic frameworks (MOFs) are regarded as the next-generation, disruptive membrane materials, yet the straightforward fabrication of ultrathin MOF membranes on an unmodified porous support remains a critical challenge. In this work, we proposed a facile, one-step electrophoretic deposition (EPD) method for the growth of ultrathin zeolitic imidazole framework-8 (ZIF-8) membranes on a bare porous support. The crystallinity, morphology and coverage of ZIF-8 particles on support surface can be optimized via regulating EPD parameters, yet it is still difficult to ensure the integrity of a ZIF-8 membrane with the constant voltage mode. In contrast, the constant current mode is more beneficial to the growth of a defect-free ZIF-8 membrane due to the steady migration rate of colloid particles toward the electrode. With a current of 0.65 mA/cm2 and deposition time of 60 min, a 300 nm thick ZIF-8 membrane was obtained, which exhibits a CO2 permeance of 334 GPU and a CO2/CH4 separation factor of 8.8, evidencing the defect-free structure.
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Ledieu, Lauriane, Ngoc-Nam Phuong, Bernard Flahaut, Pauline Radigois, Julya Papin, Cécile Le Guern, Batrice Béchet y Johnny Gasperi. "May a Former Municipal Landfill Contaminate Groundwater in Microplastics? First Investigations from the “Prairie de Mauves Site” (Nantes, France)". Microplastics 2, n.º 1 (6 de febrero de 2023): 93–106. http://dx.doi.org/10.3390/microplastics2010007.
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Municipal landfills receive a high amount of plastic waste and due to the occurring physical and biochemical degradation processes, could be significant sources of microplastics (MP). Evaluating the threat to groundwater through the transfer of MP via landfill leachates require more research. The former “Prairie de Mauves” landfill, operated from 1963 to 1987 by the municipality of Nantes (France), and located above the alluvial groundwater of the Loire River, represents a good candidate for such investigations. Leachates and groundwater were sampled along a transect line from upstream to downstream of the landfill, in March and June 2022. MP (>25 µm) were quantified and characterized using µFTIR imaging in transmission mode. MP were observed in every sample with concentrations ranging from 0.71 to 106.7 MP/L. Concentrations in the leachates and the alluvial groundwater illustrate a migration of MP. Twelve polymers were identified and polyethylene (PE) and polypropylene (PP) were predominant. After a conventional rainfall event (14.3 mm), higher concentrations, diversity, and size ranges of MP were observed. Water infiltration through the heterogeneous geological substratum therefore enhanced the migration of larger MP towards the alluvial groundwater of the Loire River.
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V. Sajitha, A. y A. C. Subhajini. "Dynamic VM Consolidation Enhancement for Designing and Evaluation of Energy Efficiency in Green Data Centers Using Regression Analysis". International Journal of Engineering & Technology 7, n.º 3.6 (4 de julio de 2018): 179. http://dx.doi.org/10.14419/ijet.v7i3.6.14966.
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Enhancement of dynamic Virtual Machines (VM) consolidation is an efficient means to improve the energy efficiency via effective resources utilization in Cloud data centers. In this paper, we propose an algorithm, Energy Conscious Greeny Cloud Dynamic Algorithm, which considers multiple factors such as CPU, memory and bandwidth utilization of the node for empowering VM consolidation by using regression analysis model. This algorithm is the combination of several adaptive algorithms such as EnCoReAn (UPReAn) for Predicting the Utility of a host), Overload and Under-load detection), VM Selection and Allocation algorithms, which helps to achieve live VM migration by switching-off unused servers to low-power mode (i.e., sleep or hibernation), thus saves energy and efficient resource utilization. This approach reduces the operational cost, computation time and increase the scalability. The experimental result proves that, the proposed algorithm attains significant percentage in reduction of energy consumption rather than existing VM consolidation strategies.
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Zhang, Shen, Jason X. J. Yuan, Kim E. Barrett y Hui Dong. "Role of Na+/Ca2+ exchange in regulating cytosolic Ca2+ in cultured human pulmonary artery smooth muscle cells". American Journal of Physiology-Cell Physiology 288, n.º 2 (febrero de 2005): C245—C252. http://dx.doi.org/10.1152/ajpcell.00411.2004.
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A rise in cytosolic Ca2+ concentration ([Ca2+]cyt) in pulmonary artery smooth muscle cells (PASMC) is an important stimulus for cell contraction, migration, and proliferation. Depletion of intracellular Ca2+ stores opens store-operated Ca2+ channels (SOC) and causes Ca2+ entry. Transient receptor potential (TRP) cation channels that are permeable to Na+ and Ca2+ are believed to form functional SOC. Because sarcolemmal Na+/Ca2+ exchanger has also been implicated in regulating [Ca2+]cyt, this study was designed to test the hypothesis that the Na+/Ca2+ exchanger (NCX) in cultured human PASMC is functionally involved in regulating [Ca2+]cyt by contributing to store depletion-mediated Ca2+ entry. RT-PCR and Western blot analyses revealed mRNA and protein expression for NCX1 and NCKX3 in cultured human PASMC. Removal of extracellular Na+, which switches the Na+/Ca2+ exchanger from the forward (Ca2+ exit) to reverse (Ca2+ entry) mode, significantly increased [Ca2+]cyt, whereas inhibition of the Na+/Ca2+ exchanger with KB-R7943 (10 μM) markedly attenuated the increase in [Ca2+]cyt via the reverse mode of Na+/Ca2+ exchange. Store depletion also induced a rise in [Ca2+]cyt via the reverse mode of Na+/Ca2+ exchange. Removal of extracellular Na+ or inhibition of the Na+/Ca2+ exchanger with KB-R7943 attenuated the store depletion-mediated Ca2+ entry. Furthermore, treatment of human PASMC with KB-R7943 also inhibited cell proliferation in the presence of serum and growth factors. These results suggest that NCX is functionally expressed in cultured human PASMC, that Ca2+ entry via the reverse mode of Na+/Ca2+ exchange contributes to store depletion-mediated increase in [Ca2+]cyt, and that blockade of the Na+/Ca2+ exchanger in its reverse mode may serve as a potential therapeutic approach for treatment of pulmonary hypertension.
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Hiram, Roddy, Edmond Rizcallah, Sofia Marouan, Chantal Sirois, Marco Sirois, Caroline Morin, Samuel Fortin y Eric Rousseau. "Resolvin E1 normalizes contractility, Ca2+ sensitivity and smooth muscle cell migration rate in TNF-α- and IL-6-pretreated human pulmonary arteries". American Journal of Physiology-Lung Cellular and Molecular Physiology 309, n.º 8 (15 de octubre de 2015): L776—L788. http://dx.doi.org/10.1152/ajplung.00177.2015.
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Pulmonary hypertension (PH) is a rare disease in which pathophysiology is characterized by an increase in proinflammatory mediators, chronic endothelial dysfunctions, and a high migration rate of smooth muscle cells (SMC). Over the course of the last decade, various treatments have been proposed to relax the pulmonary arteries, none of which have been effective in resolving PH. Our hypothesis is that artery-relaxing drugs are not the long-term solution, but rather the inhibition of tissue inflammation, which underlies human pulmonary artery (HPA) dysfunctions that lead to abnormal vasoconstriction. The goal of the present study was to assess the anti-inflammatory effects of resolvin E1 (RvE1) with concomitant effects on SMC migration and on HPA reactivity. The role and mode of action of RvE1 and its precursor, monoacylglyceride eicosapentaenoic acid were assessed on HPA under proinflammatory conditions, involving a combined pretreatment with 10 ng/ml TNF-α and 10 ng/ml IL-6. Our results show that TNF-α and IL-6 treatment induced hyperreactivity and Ca2+ hypersensitivity in response to pharmaco-mechanical stimuli, including 80 mM KCl, 1 μM phorbol 12–13-dibutyrate, and 30 nM U-46619. Furthermore, the proinflammatory treatment increased the migration rate of SMC isolated from HPA. The phosphorylation level of regulatory contractile proteins (CPI-17, MYPT-1), and proinflammatory signaling pathways (c-Fos, c-Jun, NF-κB) were also significantly increased compared with control conditions. Conversely, 300 nM RvE1 was able to normalize all of the above abnormal events triggered by proinflammation. In conclusion, RvE1 can resolve human arterial hyperreactivity via the resolution of inflammatory markers.
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Nouvel, Kevin. "La vie, mode d'esthétisation". Espaces Temps 55, n.º 1 (1994): 88–97. http://dx.doi.org/10.3406/espat.1994.3911.
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Szwec, Gérard. "La vie, mode d’emploi". Revue française de psychosomatique 61, n.º 1 (19 de octubre de 2022): 123–35. http://dx.doi.org/10.3917/rfps.061.0123.
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Szwec, Gérard. "La vie, mode d'emploi". Revue française de psychanalyse o 62, n.º 5 (1 de mayo de 1998): 1505–18. http://dx.doi.org/10.3917/rfp.g1998.62n5.1505.
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Résumé Selon l’auteur, le ratage du refoulement originaire a une place déterminante dans la genèse du fonctionnement opératoire. Chez le jeune enfant, la pensée opératoire est généralement associée à des conduites autocalmantes qui jouent unrôle dans le maintien hors psyché des représentations rejetées. A propos du collectif dans lequel s’intègre l’opératoire, l’auteur souligne que l’identification au meneur est absente.
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Wang, Luhong, Lixue Chen, Yichen Yao, Hongyan Shen y Youjun Xu. "A Mechanism Study on the (+)-ESI-TOF/HRMS Fragmentation of Some PPI Prazoles and Their Related Substances". Molecules 28, n.º 15 (3 de agosto de 2023): 5852. http://dx.doi.org/10.3390/molecules28155852.
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Fragmentation mechanisms of some prazoles and their related substances were newly investigated in this paper via positive mode ESI-TOF HRMS1 and HRMS2. Some novel fragmentation rules or ions were found or detected in the research. The pyridine and the benzoimidazole ring remained in most cases during the ionization, and heterolytic fragmentations often occurred near the -S(O)nCH2- linker to give the [1,3]-H migration ion or [1,7]-H migration ion rearranging across the benzoimdazole ring. Smiles rearrangement ionizations also frequently occurred, initiated by the attack of the lone pair electrons from the pyridine ring, and the sulfones gave special N-(2-benzoimdazolyl) pyridine ions (11b and 12c) by a direct extraction from SO2, and the thioethers gave similar framework ions (8c, 9c and 10c) via the rearrangement and a further homolytic cleavage of SH radicals. However, the sulfoxides were seldom detected in the corresponding Smiles rearrangement ions during our measurement, and the N′-oxides of the pyridines did not undergo the Smiles rearrangement ionization due to the absence of the lone pair electrons. The 5/6-membered chelating ions with Na+ or K+ were frequently detected as the molecular and further fragment ions. Some novel and interesting fragment ions containing bivalent (8b and 9b), tetravalent (4b, 5c and 6c) or hexavalent (15b and 16b) sulfurs were first reported here.
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Ifuku, M., K. Farber, Y. Okuno, Y. Yamakawa, T. Miyamoto, C. Nolte, V. F. Merrino et al. "Bradykinin-Induced Microglial Migration Mediated by B1-Bradykinin Receptors Depends on Ca2+ Influx via Reverse-Mode Activity of the Na+/Ca2+ Exchanger". Journal of Neuroscience 27, n.º 48 (28 de noviembre de 2007): 13065–73. http://dx.doi.org/10.1523/jneurosci.3467-07.2007.
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Shin, Hyeryun y Hideki Derek Kawai. "Sensitive timing of undifferentiation in oligodendrocyte progenitor cells and their enhanced maturation in primary visual cortex of binocularly enucleated mice". PLOS ONE 16, n.º 9 (17 de septiembre de 2021): e0257395. http://dx.doi.org/10.1371/journal.pone.0257395.
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Sensory experience modulates proliferation, differentiation, and migration of oligodendrocyte progenitor cells (OPCs). In the mouse primary visual cortex (V1), visual deprivation-dependent modulation of OPCs has not been demonstrated. Here, we demonstrate that undifferentiated OPCs developmentally peaked around postnatal day (P) 25, and binocular enucleation (BE) from the time of eye opening (P14-15) elevated symmetrically-divided undifferentiated OPCs in a reversible G0/G1 state even more at the bottom lamina of the cortex by reducing maturing oligodendrocyte (OL) lineage cells. Experiments using the sonic hedgehog (Shh) signaling inhibitor cyclopamine in vivo suggested that Shh signaling pathway was involved in the BE-induced undifferentiation process. The undifferentiated OPCs then differentiated within 5 days, independent of the experience, becoming mostly quiescent cells in control mice, while altering the mode of sister cell symmetry and forming quiescent as well as maturing cells in the enucleated mice. At P50, BE increased mature OLs via symmetric and asymmetric modes of cell segregation, resulting in more populated mature OLs at the bottom layer of the cortex. These data suggest that fourth postnatal week, corresponding to the early critical period of ocular dominance plasticity, is a developmentally sensitive period for OPC state changes. Overall, the visual loss promoted undifferentiation at the early period, but later increased the formation of mature OLs via a change in the mode of cell type symmetry at the bottom layer of mouse V1.
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Al Malik, Abd y Ayoko Mensah. "« La vie est une migration »". Africultures 68, n.º 3 (2006): 68. http://dx.doi.org/10.3917/afcul.068.0068.
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