Literatura académica sobre el tema "Integrin affinity"
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Artículos de revistas sobre el tema "Integrin affinity"
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Hughes, Paul E. y Martin Pfaff. "Integrin affinity modulation". Trends in Cell Biology 8, n.º 9 (septiembre de 1998): 359–64. http://dx.doi.org/10.1016/s0962-8924(98)01339-7.
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Li, Jing y Timothy A. Springer. "Energy landscape differences among integrins establish the framework for understanding activation". Journal of Cell Biology 217, n.º 1 (9 de noviembre de 2017): 397–412. http://dx.doi.org/10.1083/jcb.201701169.
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Why do integrins differ in basal activity, and how does affinity for soluble ligand correlate with cellular adhesiveness? We show that basal conformational equilibrium set points for integrin α4β1 are cell type specific and differ from integrin α5β1 when the two integrins are coexpressed on the same cell. Although α4β1 is easier to activate, its high-affinity state binds vascular cell adhesion molecule and fibronectin 100- to 1,000-fold more weakly than α5β1 binds fibronectin. Furthermore, the difference in affinity between the high- and low-affinity states is more compressed in α4β1 (600- to 800-fold) than in α5β1 (4,000- to 6,000-fold). α4β1 basal conformational equilibria differ among three cell types, define affinity for soluble ligand and readiness for priming, and may reflect differences in interactions with intracellular adaptors but do not predict cellular adhesiveness for immobilized ligand. The measurements here provide a necessary framework for understanding integrin activation in intact cells, including activation of integrin adhesiveness by application of tensile force by the cytoskeleton, across ligand–integrin–adaptor complexes.
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Liddington, R. C. y M. H. Ginsberg. "Integrin activation takes shape". Journal of Cell Biology 158, n.º 5 (2 de septiembre de 2002): 833–39. http://dx.doi.org/10.1083/jcb.200206011.
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Integrins are cell surface adhesion receptors that are essential for the development and function of multicellular animals. Here we summarize recent findings on the regulation of integrin affinity for ligand (activation), one mechanism by which cells modulate integrin function. The focus is on the structural basis of integrin activation, the role of the cytoplasmic domain in integrin affinity regulation, and potential mechanisms by which activation signals are propagated from integrin cytoplasmic domains to the extracellular ligand-binding domain.
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Dormond, Olivier, Lionel Ponsonnet, Meriem Hasmim, Alessandro Foletti y Curzio Rüegg. "Manganese-induced integrin affinity maturation promotes recruitment of αVβ3 integrin to focal adhesions in endothelial cells: evidence for a role of phosphatidylinositol 3-kinase and Src". Thrombosis and Haemostasis 92, n.º 07 (2004): 151–61. http://dx.doi.org/10.1160/th03-11-0728.
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SummaryIntegrin activity is controlled by changes in affinity (i.e. ligand binding) and avidity (i.e. receptor clustering). Little is known, however, about the effect of affinity maturation on integrin avidity and on the associated signaling pathways. To study the effect of affinity maturation on integrin avidity, we stimulated human umbilical vein endothelial cells (HUVEC) with MnCl2 to increase integrin affinity and monitored clustering of β1 and β3 integrins. In unstimulated HUVEC, β1 integrins were present in fibrillar adhesions, while αVβ3 was detected in peripheral focal adhesions. Clustered β1 and β3 integrins expressed high affinity/ligand-induced binding site (LIBS) epitopes. MnCl2-stimulation promoted focal adhesion and actin stress fiber formation at the basal surface of the cells, and strongly enhanced mAb LM609 staining and expression of β3 high affinity/LIBS epitopes at focal adhesions. MnCl2-induced αVβ3 clustering was blocked by a soluble RGD peptide, by wortmannin and LY294002, two parmacological inhibitors of phosphatidylinositol 3-kinase (PI 3-K), and by over-expressing a dominant negative PI 3-K mutant protein. Conversely, over-expression of active PI 3-K and pharmacological inhibiton of Src with PP2 and CGP77675, enhanced basal and manganese-induced αVβ3 clustering. Transient increased phosphorylation of protein kinase B/Akt, a direct target of PI 3K, occurred upon manganese stimulation. MnCl2 did not alter β1 integrin distribution or β1 high-affinity/LIBS epitope expression. Based on these results, we conclude that MnCl2-induced αVβ3 integrin affinity maturation stimulates focal adhesion and actin stress fiber formation, and promotes recruitment of high affinity αVβ3 to focal adhesions. Affinity-modulated αVβ3 clustering requires PI3-K signaling and is negatively regulate by Src.
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Yu, Tao, Xing Wu, Kiran B. Gupta y Dennis F. Kucik. "Affinity, lateral mobility, and clustering contribute independently to β2-integrin-mediated adhesion". American Journal of Physiology-Cell Physiology 299, n.º 2 (agosto de 2010): C399—C410. http://dx.doi.org/10.1152/ajpcell.00039.2009.
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Affinity changes and avidity modulation both contribute to activation of β2-integrin-mediated adhesion, an essential, early step in inflammation. Avidity modulation, defined as an increase in adhesiveness independent of integrin conformational changes, might be due to integrin clustering, motion, or both. Increased integrin diffusion upon leukocyte activation has been demonstrated, but whether it is proadhesive in itself, or just constitutes a mechanism for integrin clustering, remains unclear. To understand the proadhesive effects of integrin affinity changes, clustering, and motion, an experimental system was devised to separate them. Clustering and integrin motion together were induced by cytochalasin D (CD) without inducing high-affinity; integrin motion could then be frozen by fixation; and high affinity was induced independently by Mn2+. Adhesion was equivalent for fixed and unfixed cells except following pretreatment with CD or Mn2+, which increased adhesion for both. However, fixed cells were less adhesive than unfixed cells after CD, even though integrin clustering was similar. A simple explanation is that CD induces both clustering and integrin motion, fixation then stops motion on fixed cells, but integrins continue to diffuse on unfixed cells, increasing the kinetics of integrin/ICAM-1 interactions to enhance adhesion. Affinity changes are then independent of, and additive to, avidity effects.
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Helsten, Teresa L., Thomas A. Bunch, Hisashi Kato, Jun Yamanouchi, Sharon H. Choi, Alison L. Jannuzi, Chloe C. Féral, Mark H. Ginsberg, Danny L. Brower y Sanford J. Shattil. "Differences in Regulation ofDrosophilaand Vertebrate Integrin Affinity by Talin". Molecular Biology of the Cell 19, n.º 8 (agosto de 2008): 3589–98. http://dx.doi.org/10.1091/mbc.e08-01-0085.
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Integrin-mediated cell adhesion is essential for development of multicellular organisms. In worms, flies, and vertebrates, talin forms a physical link between integrin cytoplasmic domains and the actin cytoskeleton. Loss of either integrins or talin leads to similar phenotypes. In vertebrates, talin is also a key regulator of integrin affinity. We used a ligand-mimetic Fab fragment, TWOW-1, to assess talin's role in regulating Drosophila αPS2βPS affinity. Depletion of cellular metabolic energy reduced TWOW-1 binding, suggesting αPS2βPS affinity is an active process as it is for vertebrate integrins. In contrast to vertebrate integrins, neither talin knockdown by RNA interference nor talin head overexpression had a significant effect on TWOW-1 binding. Furthermore, replacement of the transmembrane or talin-binding cytoplasmic domains of αPS2βPS with those of human αIIbβ3 failed to enable talin regulation of TWOW-1 binding. However, substitution of the extracellular and transmembrane domains of αPS2βPS with those of αIIbβ3 resulted in a constitutively active integrin whose affinity was reduced by talin knockdown. Furthermore, wild-type αIIbβ3 was activated by overexpression of Drosophila talin head domain. Thus, despite evolutionary conservation of talin's integrin/cytoskeleton linkage function, talin is not sufficient to regulate Drosophila αPS2βPS affinity because of structural features inherent in the αPS2βPS extracellular and/or transmembrane domains.
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Tozer, Eileen Collins, Paul E. Hughes y Joseph C. Loftus. "Ligand binding and affinity modulation of integrins". Biochemistry and Cell Biology 74, n.º 6 (1 de diciembre de 1996): 785–98. http://dx.doi.org/10.1139/o96-085.
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Integrins are cell adhesion receptors that mediate cell–cell and cell–extracellular matrix interactions. The extracellular domains of these receptors possess binding sites for a diverse range of protein ligands. Ligand binding is divalent cation dependent and involves well-defined motifs in the ligand. Integrins can dynamically regulate their affinity for ligands (inside-out signaling). This ability to rapidly modulate their affinity state is key to their involvement in such processes as cell migration and platelet aggregation. This review will focus on two aspects of integrin function: first, on the molecular basis of ligand–integrin interactions and, second, on the underlying mechanisms controlling the affinity state of integrins for their ligands.Key words: integrins, ligand binding, affinity modulation.
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Dong, Xianchi, Bo Zhao, Fu-Yang Lin, Chafen Lu, Bruce N. Rogers y Timothy A. Springer. "High integrin αVβ6 affinity reached by hybrid domain deletion slows ligand-binding on-rate". Proceedings of the National Academy of Sciences 115, n.º 7 (29 de enero de 2018): E1429—E1436. http://dx.doi.org/10.1073/pnas.1718662115.
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The role of the hybrid domain in integrin affinity regulation is unknown, as is whether the kinetics of ligand binding is modulated by integrin affinity state. Here, we compare cell surface and soluble integrin αVβ6 truncation mutants for ligand-binding affinity, kinetics, and thermodynamics. Removal of the integrin transmembrane/cytoplasmic domains or lower legs has little effect on αVβ6 affinity, in contrast to β1 integrins. In integrin opening, rearrangement at the interface between the βI and hybrid domains is linked to remodeling at the ligand-binding site at the opposite end of the βI domain, which greatly increases in affinity in the open conformation. The larger size of the βI-hybrid interface in the closed state suggests that the hybrid domain stabilizes closing. In agreement, deletion of the hybrid domain raised affinity by 50-fold. Surface plasmon resonance and isothermal titration calorimetry gave similar results and the latter revealed tradeoffs between enthalpy and entropy not apparent from affinity. At extremely high affinity reached in Mn2+ with hybrid domain truncation, αVβ6 on-rate for both pro-TGF-β1 and fibronectin declined. The results suggest that the open conformation of αVβ6 has lower on-rate than the closed conformation, correlate with constriction of the ligand-binding pocket in open αVβ6 structures, and suggest that the extended-closed conformation is kinetically selected for ligand binding. Subsequent transition to the extended-open conformation is stabilized by its much higher affinity for ligand and would also be stabilized by force exerted across ligand-bound integrins by the actin cytoskeleton.
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Bialkowska, Katarzyna, Jun Qin y Edward F. Plow. "Phosphorylation of Kindlins and the Control of Integrin Function". Cells 10, n.º 4 (7 de abril de 2021): 825. http://dx.doi.org/10.3390/cells10040825.
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Integrins serve as conduits for the transmission of information between cells and their extracellular environment. Signaling across integrins is bidirectional, transducing both inside-out and outside-signaling. Integrin activation, a transition from a low affinity/avidity state to a high affinity/avidity state for cognate ligands, is an outcome of inside-signaling. Such activation is particularly important for the recognition of soluble ligands by blood cells but also influences cell-cell and cell-matrix interactions. Integrin activation depends on a complex series of interactions, which both accelerate and inhibit their interconversion from the low to the high affinity/avidity state. There are three components regarded as being most proximately involved in integrin activation: the integrin cytoplasmic tails, talins and kindlins. The participation of each of these molecules in integrin activation is highly regulated by post-translation modifications. The importance of targeted phosphorylation of integrin cytoplasmic tails and talins in integrin activation is well-established, but much less is known about the role of post-translational modification of kindlins. The kindlins, a three-member family of 4.1-ezrin-radixin-moesin (FERM)-domain proteins in mammals, bind directly to the cytoplasmic tails of integrin beta subunits. This commentary provides a synopsis of the emerging evidence for the role of kindlin phosphorylation in integrin regulation.
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Mahabeleshwar, Ganapati H., Juhua Chen, Weiyi Feng, Payaningal R. Somanath, Olga V. Razorenova y Tatiana V. Byzova. "Integrin affinity modulation in angiogenesis". Cell Cycle 7, n.º 3 (febrero de 2008): 335–47. http://dx.doi.org/10.4161/cc.7.3.5234.
Texto completoTesis sobre el tema "Integrin affinity"
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Buttery, Robert Christians. "Integrin affinity modulation and lung cancer". Thesis, University of Edinburgh, 2006. http://hdl.handle.net/1842/29025.
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Recent work has shown that the transmembrane protein CD98 is able to influence the affinity with which β1 integrins bind to extracellular ligands. The first part of this thesis presents confocal microscopy and co-immunoprecipitation experiments that confirm the physical juxtaposition of the two proteins within the cell membrane, suggesting a direct functional link between the two. It also demonstrated that cross-linking CD98 stimulates both phosphoinositide 3-kinase intracellular signalling and increased β1 integrin-dependent cellular adhesion. Because of the role of CD98 in integrin affinity modulation, the immunohistochemical expression of CD98 and its ligand, galectin-3, was studied in a variety of human ling diseases including lung cancers. The major finding of this work was a striking distinction between high expression of galectin-3 in non-small cell lung cancer and low expression in small cell lung cancer. This may hag significant implications for the differing clinical behaviours of these two groups of cancers. The final section of this thesis returns to describe experiments aimed at defining the molecular regulators of integrin affinity more clearly. A genetic screen of a cDNA library was undertaken to identify candidate genes coding for proteins able to rescue integrins from the low affinity state induced by the small signalling protein H-Ras. This identified a candidate cDNA 480, recognised to be part of a novel gene Nessie, which codes for a large protein with multiple transmembrane domains. Both 480 and Nessie appear to have the ability to rescue integrin affinity from H-Ras suppression.
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Elliott, Paul Anthony. "Integrin affinity modulation and survival signalling". Thesis, University of Edinburgh, 2008. http://hdl.handle.net/1842/4393.
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Integrins are heterodimeric transmembrane proteins that provide a bi-directional link between the cell’s internal biological mechanisms and the extracellular environment. During inside-out signalling, intracellular messages converge on the integrin cytoplasmic domain to induce a conformational change. This is transmitted to the extracellular domain where it results in an alteration in affinity for integrin ligands such as fibronectin and laminin. In this way the cell has developed the ability to modulate the critical functions of adhesion and cell movement. In outside-in signalling, the integrin performs a more complex function than simple adhesion; upon binding to ligand, the integrin extracellular domain undergoes a conformational change which is transmitted to the cytoplasmic domain. This alters the integrin’s cytoplasmic domain affinity for intracellular signalling proteins and results in the activation of intracellular second messenger pathways. In this way, the extracellular milieu is able to influence intracellular signalling including those involved in apoptosis. This thesis demonstrates data which provide original insights into bi-directional integrin signalling: Inside-out signalling: Constitutively active Notch1 increases β3-integrin affinity and abrogates Hras-mediated integrin suppression without increasing expression of β3- integrin. Dominant-Negative Rras blocks Notch-mediated integrin activation and Notch1-mediated reversal of Hras and Raf-mediated integrin suppression and this is independent of erk phosphorylation. Notch1 induces Rras activation. Functional adhesion assays confirm that Notch1IC increases K562 adhesion in a β1-integrin dependent manner and this is abrogated by Dominant-Negative Rras. This data supports a mechanism in which Notch1 increases integrin affinity via activation of Rras. Outside-in signalling: Evidence is presented demonstrating that extracellular matrix proteins, laminin and fibronectin, activate β1-integrins to protect SCLC cells against the apoptotic effects of etoposide and ionizing radiation via PI3Kinase activation. This occurs in two ways: 1) PI3Kinase-dependent β1-integrin signalling resulting in phosphorylation of Bad and reduced caspase-9 cleavage and 2) a β1-integrinmediated over-riding of etoposide and radiotherapy-induced cell cycle S phase delay and G2/M arrest. β1-integrin-mediated outside-in survival signalling was investigated further in the in vivo setting; MatrigelTM, a basement membrane product rich in extracellular matrix proteins, promoted SCLC xenograft survival and growth in a β1-integrin and tyrosine kinase-dependent manner. This data provides novel insights into the critical functions that integrins play in adhesion and survival signalling.
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Lad, Yatishkumar. "Integrin affinity modulation by Ras signalling molecules". Thesis, University of Edinburgh, 2002. http://hdl.handle.net/1842/24800.
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In this thesis I have sought to understand the mechanism by which H-Ras and its effectors modulate integrin affinity. H-Ras is a member of the Ras superfamily of small GTP binding proteins. Expression of the constitutively active variant of H-Ras (Ras G12V) within an integrin affinity reporter system (αβ-py cells) reduced integrin affinity (suppressed integrin). Ras effector mutants revealed that integrin suppression is mediated by Raf-dependent and Raf-independent signalling pathways. Raf-independent signalling pathways activated by Ral-GEFs and PI3-kinase were not recognisable for integrin suppression. An active variant of R-Ras (R-Ras G38V) reversed integrin suppression by both Raf-dependent and - independent pathways, indicating that these pathways may converge at a point proximal to the integrin. Raf initiates a protein signalling cascade leading to ERK activation that is responsible for many of the Ras/Raf-dependent biological functions. However, Raf-dependent integrin suppression was insensitive to MEK inhibition with the PD098059 compound. A novel Raf mutant (T481A) that fails to bind to MEK was also capable of mediating integrin suppression in the absence of ERK activation. Surprisingly, Raf-BxB T481A-mediated integrin suppression was sensitive to expression of MKP-1. Taken together it is proposed that Raf may mediate integrin suppression via a MEK-independent pathway that may utilise a member of the MAP kinase superfamily. In conclusion, integrin suppression by Ras is mediated by both Raf-independent and dependent pathways. Signalling by Raf may utilise components other than those present in the classical Ras to ERK protein cascade.
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Bernhagen, Dominik [Verfasser], Martin [Akademischer Betreuer] Möller y Peter [Akademischer Betreuer] Timmerman. "Bicyclic RGD peptides : Novel high-affinity ligands for selective integrin-binding and integrin-mediated cell adhesion / Dominik Bernhagen ; Martin Möller, Peter Timmerman". Aachen : Universitätsbibliothek der RWTH Aachen, 2019. http://d-nb.info/1215865511/34.
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Bernhagen, Dominik Verfasser], Martin [Akademischer Betreuer] [Möller y Peter [Akademischer Betreuer] Timmerman. "Bicyclic RGD peptides : Novel high-affinity ligands for selective integrin-binding and integrin-mediated cell adhesion / Dominik Bernhagen ; Martin Möller, Peter Timmerman". Aachen : Universitätsbibliothek der RWTH Aachen, 2019. http://d-nb.info/1215865511/34.
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SACCO, GIOVANNI. "DEVELOPMENT OF NOVEL STRATEGIES TO ENHANCE THE AFFINITY OF CYCLIC PEPTIDE LIGANDS FOR INTEGRIN RECEPTORS". Doctoral thesis, Università degli Studi di Milano, 2022. http://hdl.handle.net/2434/919134.
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The impact of monoclonal antibodies (mAbs) in current pharmaceutical research is due to their unique ability to bind biological targets with very high affinity. On the other hand, there is a considerable interest in the development of small molecule ligands with antibody-like affinities, which may overcome some limitations of mAbs.
This PhD work describes the development of general strategies to increase the binding affinity of peptide ligands bearing the Arg-Gly-Asp motif, i.e. the well-known recognition sequence of specific tumor-associated integrin receptors. In our first approach, we designed a bicyclic peptide bearing two RGD motifs that displayed an enhanced inhibition of ECM protein binding to integrin receptors αvβ3 and α5β1 and marked biological effects in U-373 MG glioblastoma cells.
Later on, we focused on the 2-hydroxybenzaldehyde tag (2HB), which can engage ϵ‐amino groups of Lys residues in stable imines. After investigating the 2HB installation to different types of reactive handles, we conjugated the 2HB tag to the N-side and on the C-side of a cyclic RGD peptide. The resulting conjugates have been investigated as novel αvβ3 integrin ligands and the nature of the ligand-protein interaction has been investigated performing in silico experiments. For both the 2HB-RGD conjugates, the biological results and the computational outcomes demonstrated to be coherent with each other, proving the feasibility of the reversible covalent engagement of Lys residues with the 2HB tag to enhance the affinity of a well-known small ligand.
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Pomies, Pascal. "Approche moléculaire de la régulation de l'adhérence cellulaire médiée par les intégrines". Université Joseph Fourier (Grenoble), 1995. http://www.theses.fr/1995GRE10011.
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A l'aide de cellules cho15b bloquees en prometaphase par du nocodazole, nous avons etudie la fonction du recepteur de la fibronectine exprime a la surface de cellules mitotiques. Une etude par cytometrie en flux a l'aide d'un anticorps dirige contre cette integrine, et des etudes de fixation de fibronectine radiomarquee sur la membrane cellulaire, montrent qu'un nombre constant d'integrines est exprime a la surface cellulaire au cours du cycle cellulaire. De plus, le recepteur de la fibronectine est toujours dans un etat de haute affinite pour son ligand soluble ou insoluble au cours de la mitose. Ces resultats indiquent que l'arrondissement des cellules observe durant la mitose ne resulte pas d'une parte de l'affinite du recepteur pour son ligand extracellulaire ; ce changement morphologique serait plutot la consequence d'une desorganisation des plaques d'adherence. A partir d'un lysat de cellules cho15b, nous avons mis au point un test in vitro afin d'etudier l'interaction de la fibronectine avec le recepteur de la fibronectine dans un environnement cytosolique. Dans ce test, l'interaction integrine/fibronectine necessite du calcium intracellulaire, la calmoduline, et une activite phosphatase. De plus, l'action d'inhibiteurs specifiques de phosphatases et l'inhibition de l'interaction integrine/fibronectine par un anticorps dirige contre la calcineurine, la phosphatase dependante du calcium et de la calmoduline, suggerent que la calcineurine permet l'interaction entre le recepteur de la fibronectine et son ligand. Des experiences de marquage metabolique montrent que l'integrine elle-meme n'est pas la cible d'une cascade de phosphorylation/dephosphorylation impliquant la calcineurine et modulant l'affinite de l'integrine. Ces resultats montrent qu'in vitro, un substrat de la calcineurine regule l'affinite du recepteur de la fibronectine en interagissant avec un effecteur non-identifie
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Robards, Brady. "Systems of Belonging: Identity, Integrity, and Affinity on Social Network Sites for Young People in Australia". Thesis, Griffith University, 2012. http://hdl.handle.net/10072/366078.
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Social network sites such as MySpace and Facebook play an important role in mediating the everyday social and cultural lives of many internet users. Young internet users were amongst the first to incorporate these sites into their everyday lives, and many young people continue to use them to connect and share with their networks, forging conventions and strategies for ‘being’ in online social spaces. For some of these young people, participation in these social spaces has become central for inclusion amongst peer groups. These sites offer a platform of mediated sociality that is distinct, while also manifesting
in forms of interaction that are familiar and embedded in the everyday, blurring distinctions between online and offline, and troubling notions of public and private.
Drawing on qualitative data collected between mid-2009 and late-2010, this thesis charts the role of the two most dominant social network sites, MySpace and Facebook, in the social lives of thirty-three young people in Australia. Fieldwork was conducted in two phases: first, through gaining access to the profiles of my participants, observing interactions and exchanges on these profiles, and analysing content; and second, drawing on these observations to frame semi-structured, in-depth, in-person interviews. At the centre of the analysis of my findings is a focus on questions of identity and self-presentation online, and how the performance of identity in online social spaces represents a reflexive ordering of self-narratives that manifest in a ‘digital trace’. I explore friending strategies, notions of integrity and authenticity, and challenge dominant conceptualisations of belonging that do not adequately encompass the systems of belonging made visible by my participants on social network sites.Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
School of Humanities
Arts, Education and Law
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Amaral, Rafael Costa. "Uma nova estratégia para o cálculo de afinidades eletrônicas". Universidade de São Paulo, 2015. http://www.teses.usp.br/teses/disponiveis/75/75134/tde-07052015-111204/.
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A afinidade eletrônica (AE) é uma importante propriedade de átomos e moléculas, sendo definida como a diferença de energia entre a espécie neutra e seu respectivo íon negativo. Uma vez que a AE é uma fração muito pequena da energia eletrônica total das espécies neutra e aniônica, é necessário que tais energias sejam determinadas com elevado grau de precisão. A receita utilizada para o cálculo teórico acurado da AE atômica e molecular baseia-se na escolha de um conjunto adequado de funções de base juntamente com o emprego de teorias com altos níveis de correlação eletrônica. Durante o cálculo, o mesmo conjunto de base é utilizado para descrever o elemento neutro e seu respectivo ânion. Geralmente, os conjuntos de base para descrever propriedades de ânions possuem seus expoentes otimizados em ambiente neutro, e sua difusibilidade é conferida pela adição de funções difusas para cada valor de momento angular, l. A ideia deste trabalho está no desenvolvimento de conjuntos de base otimizados exclusivamente em ambiente aniônico para cálculos precisos de afinidade eletrônica. Deste modo, foram escolhidos os átomos para serem estudados: B, C, O e F. Os conjuntos de base foram gerados pelo Método da Coordenada Geradora Hartree-Fock, empregando a técnica da Discretização Integral Polinomial para a solução das integrais do problema. Os conjuntos de base obtidos são compostos por (18s13p) primitivas que foram contraídos para [7s6p] via esquema de contração geral proposto por Raffenetti. Os conjuntos contraídos foram polarizados para 4d3f2g e 4d3f2g1h, sendo os expoentes otimizados em ambiente CISD através do método SIMPLEX. Avaliaram-se as funções de base no cálculo de afinidades eletrônicas, tendo seus resultados comparados aos obtidos utilizando as bases aug-cc-pVQZ e aug-cc-pV5Z. A análise dos resultados demonstrou que os conjuntos de base difusos, gerados neste trabalho, reproduzem de maneira satisfatória as afinidades eletrônicas em relação ao valor experimental. Os conjuntos difusos polarizados para 4d3f2g1h apresentaram eficiência superior aos conjuntos aug-cc-pVQZ e, em alguns casos, aos conjuntos aug-cc-pV5Z que são consideravelmente maiores.The electron affinity (EA) is an important property of atoms and molecules defined as the energy difference between the neutral species and its negative ion. Since the EA is a very small fraction of the total electronic energy of anionic and neutral species, one must determine these energies with high accuracy. The recipe used to calculate accurate atomic and molecular EAs is based on the choice of an adequate basis set and the use of high level of electron correlation calculations. In the computation of EAs, the same basis set is used to describe both neutral and negatively charged species. In general, the basis sets designed to describe anionic properties have their exponents optimized in neutral environment, and its diffuseness is acquired through the addition of diffuse functions for each angular momentum. The main idea of this work is to develop basis sets optimized exclusively in anionic environment that would be applied in accurate calculations of electron affinity. Thus, here follows the chosen atoms to be studied: B, C, O and F. The basis sets were generated by the Generator Coordinate Hartree-Fock Method through the Polynomial Integral Discretization Method. Basis sets were obtained containing (18s13p) primitives that were contracted to [7s6p] via Raffenetti\'s general contraction scheme. The contracted basis sets were polarized to 4d3f2g and 4d3f2g1h, and the exponents of polarization were optimized in a CISD environment through the Simplex algorithm. The basis sets quality was evaluated through the calculation of the electron affinities. The results were compared to those obtained by using the aug-cc-pVQZ and aug-cc-pV5Z basis-sets. The calculation showed that our diffuse basis sets reproduce satisfactorily the electron affinities when compared to the experimental data. The diffuse basis sets polarized to 4d3f2g1h showed to be more efficient than the aug-cc-pVQZ basis sets and in some cases also better than the aug-cc-pV5Z basis sets that are considerably larger.
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DiVietro, Jeffrey Anthony. "The role of chemokines and integrin affinity in leukocyte adhesion /". 2005. http://wwwlib.umi.com/dissertations/fullcit/3169703.
Texto completoLibros sobre el tema "Integrin affinity"
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Laidler-Kylander, Nathalie y Julia Shepard Stenzel. Brand IDEA: Managing Nonprofit Brands with Integrity, Democracy, and Affinity. Wiley & Sons, Incorporated, John, 2013.
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Laidler-Kylander, Nathalie y Julia Shepard Stenzel. Brand IDEA: Managing Nonprofit Brands with Integrity, Democracy, and Affinity. Wiley & Sons, Incorporated, John, 2013.
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Laidler-Kylander, Nathalie y Julia Shepard Stenzel. Brand IDEA: Managing Nonprofit Brands with Integrity, Democracy, and Affinity. Wiley & Sons, Incorporated, John, 2013.
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1964-, Stenzel Julia Shepard, ed. The brand IDEA: Managing nonprofit brands with integrity, democracy, and affinity. Jossey-Bass, 2014.
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Henning, C. Randall. Spain and Italy. Oxford University Press, 2017. http://dx.doi.org/10.1093/oso/9780198801801.003.0007.
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Spain and Italy posed threats to the integrity of the monetary union that were a magnitude greater than those posed by the previous crisis countries. Owing in part to actions by the European Central Bank, the program for Spain could be limited nominally to its banking system, while Italy could avoid a program altogether. The Spanish program’s institutional arrangement is best understood as a variation on, rather than a rejection of, the troika. It was linked to Spain’s commitment to fiscal austerity and structural reform, while the International Monetary Fund was involved in program design and monitoring. Political affinity between the governments of Spain and Germany and the economic size of Spain explain the choice of the institutional arrangement. Owing to Spain’s size, the IMF would have required adjustments in euro-area policies to which member states and the ECB were not willing to agree. Key member states were thus pivotal in defining the roles of the institutions.
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Roe, Simon, ed. Protein Purification Techniques. Oxford University Press, 2001. http://dx.doi.org/10.1093/oso/9780199636747.001.0001.
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Proteins are an integral part of molecular and cellular structure and function and are probably the most purified type of biological molecule. In order to elucidate the structure and function of any protein it is first necessary to purify it. Protein purification techniques have evolved over the past ten years with improvements in equipment control, automation, and separation materials, and the introduction of new techniques such as affinity membranes and expanded beds. These developments have reduced the workload involved in protein purification, but there is still a need to consider how unit operations linked together to form a purification strategy, which can be scaled up if necessary. The two Practical Approach books on protein purification have therefore been thoroughly updated and rewritten where necessary. The core of both books is the provision of detailed practical guidelines aimed particularly at laboratory scale purification. Information on scale-up considerations is given where appropriate. The books are not comprehensive but do cover the major laboratory techniques and common sources of protein. Protein Purification Techniques focuses on unit operations and analytical techniques. It starts with an overview of purification strategy and then covers initial extraction and clarification techniques. The rest of the book concentrates on different purification methods with the emphasis being on chromatography. The final chapter considers general scale-up considerations. Protein Purification Applications describes purification strategies from common sources: mammalian cell culture, microbial cell culture, milk, animal tissue, and plant tissue. It also includes chapters on purification of inclusion bodies, fusion proteins, and purification for crystallography. A purification strategy that can produce a highly pure single protein from a crude mixture of proteins, carbohydrates, lipids, and cell debris to is a work of art to be admired. These books (available individually or as a set)are designed to give the laboratory worker the information needed to undertake the challenge of designing such a strategy.
Capítulos de libros sobre el tema "Integrin affinity"
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"Electoral Integrity, Ethnic Affinity, and Religious Revival in Nigeria’s Party Turnover". En Contemporary Nigerian Politics, 148–78. Cambridge University Press, 2018. http://dx.doi.org/10.1017/9781108560467.005.
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Kim, Mi Gyung. "Chemical Laboratory and the Cosmic Space". En Space, 270–79. Oxford University Press, 2020. http://dx.doi.org/10.1093/oso/9780199914104.003.0011.
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Early modern chemistry configured the laboratory as a productive domain of useful material knowledge, which weakened its symbolic association with the cosmic space while strengthening its social status in the emergent civic order. The experimental production of vacuum by the Royal Society and the mathematical homogenization of space by Newton made chemistry an integral part of natural philosophy which in turn legitimized Anglican natural theology. The laboratory in Restoration England became the site of crafting a universal order. French representation of chemical reality in the affinity table during the Enlightenment projected, however, a disciplined material world a modern chemist could command, entirely dissociated from cosmic mystery.
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Coto, Kathryn. "Racebending Potter". En Harry Potter and the Other, editado por Sarah Park Dahlen y Ebony Elizabeth Thomas, 119–43. University Press of Mississippi, 2022. http://dx.doi.org/10.14325/mississippi/9781496840578.003.0007.
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This chapter looks at a specific type of resistant fan production—racebent Harry Potter fanart, which adds diversity to canon by reimagining canonically white characters as people of color—to explore how memory and the cultural process of remembering together via social media affinity spaces are integral to a critical, antiracist project realized through racebending fan artists' work. This chapter places fan voices in dialogue with the academic critique of race in Rowling's novels and film adaptations, and examines several fanart images that are drawings of imaginary photographs or photographic cosplay art and their metatexts—or hashtags and written commentary—to emphasize fanart's sophisticated, multi-layered intertextuality or metafictionality. This paper argues that despite its complexity as text, the visual medium gives racebent Potter fanart currency as an activist tool, connecting to both a larger antiracist activist tradition and a contemporary activist movement.
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Tenzer, Michael. "That’s All It Does". En Rethinking Reich, 303–22. Oxford University Press, 2019. http://dx.doi.org/10.1093/oso/9780190605285.003.0014.
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Though integral to his formation as a composer, Steve Reich’s studies of Balinese gamelan have been overlooked. In part this is because of a certain redundancy: features of Balinese overlap significantly with the West African music whose impact on Reich’s formative works of the 1970s has been amply demonstrated. These include predominance of percussion, repetitive cyclic structures, interlocking rhythms, systems of oral transmission, and the nonprofessional ethos of the performing ensemble’s interactive behaviors. But what of the features of the Balinese music Reich studied and did not assimilate? Among these are malleable tempo, extended and minimally repetitive cycles, and tonally hierarchic melodies rooted in Southeast Asian traditions of sung poetry. Their eschewal opens pathways for insight into Reich’s music, as well as his cultural subjectivity, in the process illuminating unsuspected aesthetic affinity between his detractors among “uptown” composition apologists of the time and traditional Balinese musicians.
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Manning, Jane. "HUGH WOOD (b. 1932)The Isles of Greece (2007)". En Vocal Repertoire for the Twenty-First Century, Volume 2, 232–35. Oxford University Press, 2021. http://dx.doi.org/10.1093/oso/9780199390960.003.0072.
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This chapter discusses British composer Hugh Wood’s The Isles of Greece (2007). This cycle, begun some years ago, has been heavily revised and gives a fascinating insight into the composer’s progression from post-Schoenbergian modernism into a new vein of sensuous, unabashed romanticism. Each song is distinct in style, but all bear evidence of Wood’s customary attributes of integrity, confident musicality, and refined aural and poetic sensibility. He admits to a deep and abiding affinity with Greece and has assembled an appetizing sequence of poems which convey the vibrant colours and mercurial emotions conjured up by that land. To do justice to the piece, the singer will need a reliable, polished technique. Although medium voice is stipulated, all except the first song are written in the bass clef, and a lightish baritone would seem to be ideal. Dynamic details are a crucial factor, and must be closely observed. Idiomatic piano writing, freely expressive and satisfyingly varied, makes a major contribution.
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Williams, Howard. "Firing the Imagination: Cremation in the Museum". En Archaeologists and the Dead. Oxford University Press, 2016. http://dx.doi.org/10.1093/oso/9780198753537.003.0022.
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The displays of articulated, unburned, and fleshed human remains in European museums are often claimed to fixate and simultaneously repulse the modern viewer, and provoke all manner of varied responses in between these extremes (Brooks and Rumsey 2007: 279–80). Unused to the sights (and smells) of corpses and skeletons, the modern visitor is certainly fascinated by the uncanny nature of the archaeological dead. While bearing the signs of transformation by time and treatment, they often retain an unsettling individual persona, regularly enhanced by being posed, re-clothed, and sometimes awarded facial reconstructions when selected for museum display (Swain 2002, 2007a; Wallace 2005). Seemingly denying and disrupting the passage of time and drawing the past into the present, these cadavers afford the illusion of sleeping persons suspended between animation and oblivion (see also Nordström this volume). Such ‘immortals’ can become emblematic of entire societies and periods in the human past and icons of archaeology itself as a discipline that deals with the traces of human mortality through time (Nordström 2007, this volume; Williams 2009). It is the strikingly ‘human’ and ‘whole’ cadavers that have provoked the strongest emotional responses from the public as well as securing direct spiritual connections for particular religious minority groups. Such is the case of the campaign by the British Order of Druids who focused their claim for reburial centred on the memorable and evocative skeleton of a Neolithic child ‘Charlie’ on display in the Keiller Museum at Avebury (see Giles and Williams this volume; Tatham this volume; Rathouse this volume). Such claims of affection and affinity are clearly predicated on the corporeal integrity and the emotive responses this integrity evokes for the viewer. While human remains provoke the most powerful emotive engagements with the archaeological dead, other strategies for displaying mortuary contexts, such as casts of human bone (Goodnow 2006a: 18–19) and artist’s reconstructions of funerals (Williams 2009; Giles this volume), can inspire strong reactions. The same also applies to dioramas with mannequins: their uncanny resemblances to living persons can create powerful imaginative and educational connections between visitors and past individuals and the societies they represent within the museum context.
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"Managing Centrarchid Fisheries in Rivers and Streams". En Managing Centrarchid Fisheries in Rivers and Streams, editado por Travis R. Ingram, Steven M. Sammons, Adam J. Kaeser, Rachel A. Katz y Sean C. Sterrett. American Fisheries Society, 2019. http://dx.doi.org/10.47886/9781934874523.ch11.
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<em>Abstract.</em>—Shoal Bass <em> Micropterus cataractae </em>are fluvial specialists endemic to the Apalachicola-Chattahoochee-Flint River Basin that are considered to be in decline throughout their native range. Effective conservation requires a comprehensive understanding of the migratory behavior and multi-scale habitat associations of Shoal Bass with riverine shoals, the critical mesohabitat upon which the species depends. We assessed movement patterns and habitat use of Shoal Bass using radio telemetry in the lower 24 km of Ichawaynochaway Creek, a 6th-order tributary of the Flint River and one of the few relatively undisturbed streams inhabited by this species. In general, Shoal Bass exhibited relatively low movement rates with increased movement in the spring, and no tagged Shoal Bass migrated from the creek into the Flint River during the study period. Most study fish preferred moderate depths (<2 m) and swift velocities during the year, and higher velocities in the winter, potentially reflecting seasonal changes in flow. These conditions were routinely satisfied through occupation of a 9-km reach with a network of large shoal complexes. Shoal Bass exhibited a distinct preference for close proximity to large shoals, and an affinity for greater depth variability associated with edge and boundary conditions within discrete shoal complexes. Despite previous studies that have documented high movement of this species in other systems, these findings suggest that the Ichawaynochaway Creek Shoal Bass population may be relatively sedentary and associate to specific areas that provide suitable habitat. This may have implications for assessing the integrity, distribution, and abundance of suitable Shoal Bass habitat in small karst limestone streams, designing projects for restoration or enhancement of existing habitat, and gauging the species vulnerability to threats such as habitat loss, introgression, and hybridization.
Actas de conferencias sobre el tema "Integrin affinity"
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Bayless, Kayla J. y George E. Davis. "AFFINITY OF OSTEOPONTIN FOR LEUKOCYTE INTEGRINS, EXTRACELLULAR MATRICES AND APOPTOTIC CELLS". En 3rd International Conference on Osteopontin and SIBLING (Small Integrin-Binding Ligand, N-linked Glycoprotein) Proteins, 2002. TheScientificWorld Ltd, 2002. http://dx.doi.org/10.1100/tsw.2002.235.
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Han, Zhihao, Shuaishuai Gong, Zhiyu Qian y Yueqing Gu. "Virtual screened peptides with high affinity to integrin α 5 β 1 for precise tumor identification and treatment". En Biophotonics and Immune Responses XV, editado por Wei R. Chen. SPIE, 2020. http://dx.doi.org/10.1117/12.2544502.
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Hsieh, Chia-Fen, Bo-Jui Chang, Chyi-Huey Pai, Hsuan-Yi Chen, Sien Chi, Long Hsu, Jin-Wu Tsai y Chi-Hung Lin. "Identification of stepped changes of binding affinity during interactions between the disintegrin rhodostomin and integrin α IIb β 3 in living cells using optical tweezers". En Optical Science and Technology, the SPIE 49th Annual Meeting, editado por Kishan Dholakia y Gabriel C. Spalding. SPIE, 2004. http://dx.doi.org/10.1117/12.558653.
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Song, Xiaoqi, Yukio Takahashi, Tohru Ihara y Weiming He. "Effects of the Size of Built-Up Layer on the Wear of Uncoated Cemented Carbide Tools in Dry Cutting of SUS304 Stainless Steel". En JSME 2020 Conference on Leading Edge Manufacturing/Materials and Processing. American Society of Mechanical Engineers, 2020. http://dx.doi.org/10.1115/lemp2020-8549.
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Abstract Built-up layer (BUL) formed on the tool rake face during cutting has the tool protective effect. As BUL can change the shape of tool resulting in variation of rake angle and edge radius during cutting, it also has significant influences on the cutting phenomena such as tool wear, cutting forces and surface integrity. SUS304 stainless steel is very difficult to cut, leading to the rapid tool wear and poor surface quality. It also has a high tendency to form BUL during cutting due to its high work hardening rate and high chemical affinity. To actively and purposely utilize BUL, the effects of the size of BUL on the wear of uncoated cemented carbide tools in dry cutting of SUS304 were investigated using experimental and analytical methods in this study. The cutting parameters were chosen to induce the stable BUL formation. After cutting, the worn cutting tools were analyzed using the laser confocal microscopy and scanning electron microscopy. It was confirmed that BUL can reduce the tool flank wear rate in the steady-state wear when its height is equal to or less than the uncut chip thickness. The results also showed that BUL formed at cutting speed 40 m/min can not only reduce the tool flank wear rate but also induce a significant improvement in cutting forces and surface integrity. Meanwhile, using the obtained experimental results and proposed model, simulation was conducted to evaluate the effects of the size of BUL on the tool flank wear formation. It was confirmed that BUL, especially when its height is close to the uncut chip thickness, which reduces the real rake angle to negative, can reduce the normal stress on the tool flank face and lead to a decrease in the tool flank wear rate.
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Morrissey, J. H., D. S. Fair y T. S. Edgington. "STRUCTURE AND PROPERTIES OF THE HUMAN TISSUE FACTOR APOPROTEIN". En XIth International Congress on Thrombosis and Haemostasis. Schattauer GmbH, 1987. http://dx.doi.org/10.1055/s-0038-1643738.
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Tissue factor (TF), an integral membrane glycoprotein, is an initiating molecule for the coagulation protease cascade. TF must reside in a phospholipid membrane for optimal activity where it functions as the receptor and essential allosteric activator for factor Vll/VIIa.TF apoprotein was purified from human brain and placenta using factor Vll-affinity chromatography or immunoaffinity chromatography with a mouse anti-TF monoclonal antibody. Both methods resulted in a homogeneous preparation consisting of a highly glycosylated 47 kDa heavy chain and a 12.5 kDa light chain.Removal of asparagine-linked carbohydrate chains with glycopeptidase F reduced the apparentmolecular weight of the heavy chain to 37 kDa but hadno effect on the mobility of the light chain in SDS gel electrophoresis. Electrophoretic analysis of theintact protein with and without reduction indicates that the light chain is disulfide-linked to the heavychain in about half of the TF molecules and is notessential for function.The majority of polyclonal andtwenty- nine monoclonal antibodies against purified TF strongly inhibit coagulation and in all cases aredirected against epitopes on the heavy chain alone. Functional regions of the TF heavy chain have been investigated using a library of twenty-nine monoclonalantibodies and a series of overlapping, synthetic oligopeptides based on sequence information obtained from cloning the cDNA for TF. Supported by NIH grantsHL-16411 and CA-41085.
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Belin, D., D. Baccino, A. Wohlwend, A. Estreicher, J. Hurate y J.-D. Vassalli. "A CELLULAR RECEPTOR FOR UROKINASE-TYPE PLASMINOGEN ACTIVATOR". En XIth International Congress on Thrombosis and Haemostasis. Schattauer GmbH, 1987. http://dx.doi.org/10.1055/s-0038-1642957.
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Recent cell biological and biochemical studies on the urokinase-type plasminogen activator (u-PA) have revealed an unsuspected property of this protein: it binds with high affinity and specificity to the plasma membrane of a number of cell types. Hence, while the interaction of tissue-type plasminogen activator (t-PA) with fibrin suggests a preferred role for this enzyme in the maintenance of fluidity of the extracellular milieu, the cellular binding of u-PA results in the focalisation of plasmin generation to the close environment of the cell surface; this appears as an optimal configuration if u-PA is to participate in the enzymatic events required for cell migration.The available information on the cellular binding of u-PA can be summarized as follows:1. Human monocytes-macrophages, monocyte-like cell lines, fibroblasts, and a variety of other cell lines all express u-PA binding sites. The number of u-PA binding sites on a given cell type may vary as a function of the functional state of the cells. In some cases all sites are occupied by “endogenous” u-PA.2. Binding does not require u-PA activity, and prou-PA binds with the same affinity as does the active enzyme.3. The Kd for u-PA binding is between 1 and 10×10-10 M. The binding site appears to be specific for u-PA.4. Binding requires the presence of the A chain of u-PA; the growth factor module of the A chain is involved in this interaction.5. Bound enzyme does not dissociate readily, nor is it rapidly endocytosed; most importantly, it retains catalytic activity.Studies in progress are aimed at further defining the u-PA determinants responsible for binding. In this context it is noteworthy that there is a tight species specificity of binding: human and murine u-PA, for instance, bind only to cells of the homologous species. Characterization of the u-PA binding site suggests that it is an integral membrane protein that includes at least one Mf 50.000 polypeptide chain.In addition to allowing for the peri-cellular focalisation of u-PA catalysed proteolysis, expression of the u-PA binding site provides a mecanism whereby one cell type can acquire membrane-bound u-PA activity following secretion of the (pro)enzyme by another cell population. A striking example of this is the binding of u-PA, synthesized by the epithelial layer of the male genital tract, to the head region of murine spermatozoa.
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Giancotti, F. G., L. R. Languino, A. Zanetti, G. Grignani, G. Tarone y E. Dejana. "PLATELETS EXPRESS A MEMBRANE PROTEIN COMPLEX IMMUNOLOGICALLY RELATED TO THE FIBROBLAST FIBRONECTIN RECEPTOR". En XIth International Congress on Thrombosis and Haemostasis. Schattauer GmbH, 1987. http://dx.doi.org/10.1055/s-0038-1643909.
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The heterodimer complex GpIIb-IIIa on human platelets can specifically bind fibronectin (FN) only when platelets are activated by thrombin. However unstimulated platelets can adhere and spread on a FN substratum. This suggests the existence of a second binding site for FN on the platelet surface that does not require activation for its expression. We have previously identified and characterized a membrane glycoprotein complex (Gp 150/135) that functions as fibronectin receptor (FN-R) in mouse fibroblast adhesion. To investigate whether this molecule was also present in platelets we have produced an affinity purified polyclonal antibodies monospecific for the lower subunit of the fibroblast FN-R. These antibodies specifically stained human and rat platelet surface as determined by fluorescence flow cytometric analysis and reacted with a component of 138 Kd m w in Western blot of platelet membranes. Experiments of differential extraction revealed that the 138 Kd component is an integral membrane protein. Moreover the antibodies precipitated the 138 Kd component together with a 160 Kd protein suggesting that the two molecules are associated in a supramolecular complex. A comparative analysis indicated that this protein complex is clearly distinct from the GpIIb-IIIa. In addition platelets from a thrombastenic patient reacted normally with 138 Kd but not with GpIIb-IIIa antibodies by Western blot analysis. These data indicate that normal human platelets express both GpIIb-IIIa and FN-R on their membrane and that these receptors are composed of structurally and antigenically distinct proteins.
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Mohite, Nikita, Sachin Biradar, Jyoti Shankar Jha, Sushil Mishra y Asim Tewari. "Development and Removal of Alpha-Case Layer From Heat Treated Titanium Alloys". En ASME 2017 Gas Turbine India Conference. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/gtindia2017-4894.
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The components of the aero engines such as fan blades are generally manufactured from Titanium alloy forgings. At the elevated temperatures, the affinity of Titanium towards oxygen is very high, which results in formation of oxide layer on surface known as alpha-case layer. This alpha-case is both hard and brittle in nature which results in localized micro failure during its application. This gives rise to a fatigue crack initiation zone and compromises the integrity of the component, causing it to fail. To investigate this, Titanium α-β (Ti 64), α (Sn) and β (Mo) alloys were heat treated at 1010°C for 30min, 60min, 90min and 120min followed by air cooling. Formation of alpha-case layer in Ti-6Al-4V, Ti-Sn and Ti-Mo increased from 120.5μm to 391.1μm, 128.77μm to 443.23μm, 105.75μm to 262.46μm at 30mins and 120mins respectively. Chemical treatment, cathodic de-oxygenation, surface coating and laser ablation methods are generally used to remove the alpha case. In the current study, acid pickling is used to remove the alpha case layer, as this process is simple and also easily applicable to any complex shape of the material. In this method, samples were dipped in the solution of HF (5%) and HNO3 (35%) at 80 °C for fixed time at fixed intervals to find the rate of alpha case removal. Micro indentation was carried out to obtain hardness profile from surface to bulk of heat treated specimen. The quantification of alpha case oxide layer from surface to bulk was done by EDS.
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Farooq, Khalid. "Varnish Removal and Control in Turbine Lubrication Systems". En ASME 2009 Power Conference. ASMEDC, 2009. http://dx.doi.org/10.1115/power2009-81173.
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Varnish deposits on metal surfaces in turbine lube system results in a number of adverse operational issues, especially the restriction and sticking of moving mechanical parts such as servo or directional control valves. The oil has limited solvency for the material, hence a typical turbine will have the majority of the material as deposits and a relatively small portion as suspended material in the oil phase in quasi-equilibrium with the deposits. The lube system needs to be cleaned by removing the suspended varnish precursors from the oil phase, which allows the deposits to re-entrain into the oil phase, until the majority of the transferable deposits from internal surfaces are removed and the oil carries no significant amount of the material to have any adverse effect. The methods used for the removal of varnish from turbine lube oil systems include chemical cleaning - flushing, and electrostatic charge induced agglomeration - retention and the adsorption of the oil suspended varnish on an adsorbent medium. The paper discusses an absorption based removal method that utilizes a fibrous medium that has pronounced affinity for the removal and retention of the varnish forming material from the oil and the deposits from surfaces that are in quasi-equilibrium with the varnish precursors in the oil. The filtration medium is composite cellulose with specially formulated, temperature cured binder resins. The absorptive medium that exhibits high structural and chemical integrity has been thoroughly tested on operating turbines, showing reduction in varnish levels from critical range to below normal range in a relatively short time. The experiences with the utilization of the absorptive medium in laboratory tests and in two operating turbines are presented.
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Morrissey, J. H., S. A. Gregory y T. S. Edgington. "DIFFERENTIAL EXPRESSION AND SUBCELLULAR LOCALIZATION OF TISSUE FACTORIN A CONSTITUTIVE VERSUS AN INDUCIBLE CELL TYPE". En XIth International Congress on Thrombosis and Haemostasis. Schattauer GmbH, 1987. http://dx.doi.org/10.1055/s-0038-1643739.
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Tissue factor (TF) is an integral membraneglycoprotein and receptor present on a variety of cells outside of the vasculature, but normally absent from intravascular cells. TF plays a central role in initiation of coagulation by rapidly binding and allosterically activating bound factor Vll/VIIa, which proteoly-tically activates coagulation factors IX and X. This protease cascade appears to play a role in the cellular inflammatory response, during which endothelial cells and monocytes/macrophages can be induced to express cell surface TF.Monocyte TF can be induced in response to endotoxin and also via direct interaction with activated T cells and by a specific lymphokine.We have developed a panel of polyclonaland twenty-nine high affinity monoclonal antibodies to human TF. The antibodies recognize TF epitopes under a broad range of conditions, some of which rapidly and efficiently neutralize <95% of TF activity isolated from brain, placenta and expressed bycultured cells. Using these antibodies in immunohistochemical assays, we haveobserved little or no TF antigen cytologically associated with resting monocytes, noTF activity, and following stimulation, the cytologic appearance of TF antigen parallels the acquisition of TF activity.Immunohistochemical staining of stimulated monocytesis diffuse, consistent with homogeneous cell-surface distribution of the TF molecule.In addition, the normal human fibroblastic cell lines GM1380 and GM1381, whichexpress TF const itutively, show a cytologically different and much more intense pattern of intracellular inclusions of TF. This is consistent with previous observationsthat lysed cells show about five-fold moreTF activity than do intact cells. These findings indicate the presence of an intracellular storage site for TF in some cell types, a pattern presently associated only with constitutive expression of this receptor protein. In addition, they confirm thatTF is induced in stimulated monocytes rather than translocation or modification. Supported by NIH grants HL-16411 and CA-41085.