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Статті в журналах з теми "Adhesive Interactions"
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Mercedes Pastor-Blas, M. M. "Compatibility Improvement between Chlorinated Thermoplastic Rubber and Polychloroprene Adhesive." Rubber Chemistry and Technology 82, no. 1 (March 1, 2009): 18–36. http://dx.doi.org/10.5254/1.3548238.
Повний текст джерелаАнотація:
Abstract Traditionally, it has been believed that there is an incompatibility between the chlorinated rubber surface and polychloroprene adhesives resulting in a lack of adhesion. However, in this study it has been shown that a polychloroprene adhesive (PCP30P) produces similar T-peel strength values when using a polyurethane (PU) adhesive in joints produced between a chlorinated thermoplastic SBS rubber and roughened leather. In both cases a cohesive failure mode within the rubber was obtained. This polychloroprene adhesive (PCP30P) contains a thermoreactive phenolic resin in its formulation. The nature of the resin greatly influences the viscoelastic properties of the polychloroprene adhesive. Thus, polychloroprene adhesive with no resin or with resins of a different nature do not produce suitable adhesive joints between the chlorinated rubber and the leather (Terpene phenolic resin (PCP30TP), a glycerol esther colofony resin (PCP30EC) and an aromatic hydrocarbon resin (PCP30AH) were studied). The interactions produced between the chlorinating agent and the adhesive were studied by ATR-IR on solid films of the polychloroprene adhesives and the tackifier resins previously immersed in the chlorinating solution (0.5 and 3 wt% TCI/MEK). All the polychloroprene adhesives were modified by the chlorinating agent, being capable of producing a good interaction with the chlorinated rubber surface at the interface. Therefore, the good performance of the PCP30P adhesive compared with the other polychloroprene adhesives has been ascribed to rheological behavior more similar to the PU adhesive assessed by DMTA. The PCP30P adhesive is the most elastic material among all the considered polychloroprene adhesives. This increased elasticity and better viscoelastic properties are imparted by the thermoreactive phenolic resin in its formulation.
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Feng, Chen, Fang Wang, Zheng Xu, Huilin Sui, Yong Fang, Xiaozhi Tang, and Xinchun Shen. "Characterization of Soybean Protein Adhesives Modified by Xanthan Gum." Coatings 8, no. 10 (September 26, 2018): 342. http://dx.doi.org/10.3390/coatings8100342.
Повний текст джерелаАнотація:
The aim of this study was to provide a basis for the preparation of medical adhesives from soybean protein sources. Soybean protein (SP) adhesives mixed with different concentrations of xanthan gum (XG) were prepared. Their adhesive features were evaluated by physicochemical parameters and an in vitro bone adhesion assay. The results showed that the maximal adhesion strength was achieved in 5% SP adhesive with 0.5% XG addition, which was 2.6-fold higher than the SP alone. The addition of XG significantly increased the hydrogen bond and viscosity, as well as increased the β-sheet content but decreased the α-helix content in the second structure of protein. X-ray diffraction data showed significant interactions between SP molecules and XG. Scanning electron microscopy observations showed that the surface of SP adhesive modified by XG was more viscous and compact, which were favorable for the adhesion between the adhesive and bone. In summary, XG modification caused an increase in the hydrogen bonding and zero-shear viscosity of SP adhesives, leading to a significant increase in the bond strength of SP adhesives onto porcine bones.
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Narayanan, Amal, Ali Dhinojwala, and Abraham Joy. "Design principles for creating synthetic underwater adhesives." Chemical Society Reviews 50, no. 23 (2021): 13321–45. http://dx.doi.org/10.1039/d1cs00316j.
Повний текст джерелаАнотація:
Water prevents adhesion by disrupting the interfacial interactions and weakening the cohesive network of the adhesive. This review summarizes the recent developments in the physical and chemical design principles of underwater adhesives.
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Taylor, James T., Rebekka Harting, Samer Shalaby, Charles M. Kenerley, Gerhard H. Braus, and Benjamin A. Horwitz. "Adhesion as a Focus in Trichoderma–Root Interactions." Journal of Fungi 8, no. 4 (April 6, 2022): 372. http://dx.doi.org/10.3390/jof8040372.
Повний текст джерелаАнотація:
Fungal spores, germlings, and mycelia adhere to substrates, including host tissues. The adhesive forces depend on the substrate and on the adhesins, the fungal cell surface proteins. Attachment is often a prerequisite for the invasion of the host, hence its importance. Adhesion visibly precedes colonization of root surfaces and outer cortex layers, but little is known about the molecular details. We propose that by starting from what is already known from other fungi, including yeast and other filamentous pathogens and symbionts, the mechanism and function of Trichoderma adhesion will become accessible. There is a sequence, and perhaps functional, homology to other rhizosphere-competent Sordariomycetes. Specifically, Verticillium dahliae is a soil-borne pathogen that establishes itself in the xylem and causes destructive wilt disease. Metarhizium species are best-known as insect pathogens with biocontrol potential, but they also colonize roots. Verticillium orthologs of the yeast Flo8 transcription factor, Som1, and several other relevant genes are already under study for their roles in adhesion. Metarhizium encodes relevant adhesins. Trichoderma virens encodes homologs of Som1, as well as adhesin candidates. These genes should provide exciting leads toward the first step in the establishment of beneficial interactions with roots in the rhizosphere.
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Klingelhofer, J., R. B. Troyanovsky, O. Y. Laur, and S. Troyanovsky. "Amino-terminal domain of classic cadherins determines the specificity of the adhesive interactions." Journal of Cell Science 113, no. 16 (August 15, 2000): 2829–36. http://dx.doi.org/10.1242/jcs.113.16.2829.
Повний текст джерелаАнотація:
Classic cadherins are transmembrane receptors involved in cell type-specific calcium-dependent intercellular adhesion. The specificity of adhesion is mediated by homophilic interactions between cadherins extending from opposing cell surfaces. In addition, classic cadherins can self-associate forming lateral dimers. Whereas it is widely excepted that lateral dimerization of cadherins is critical for adhesion, details of this process are not known. Yet, no evidence for physical association between different classic cadherins in cells expressing complex cadherin patterns has been reported. To study lateral and adhesive intercadherin interactions, we examined interactions between two classic cadherins, E- and P-cadherins, in epithelial A-431 cells co-producing both proteins. We showed that these cells exhibited heterocomplexes consisting of laterally assembled E- and P-cadherins. These complexes were formed by a mechanism involving Trp(156) of E-cadherin. Removal of calcium ions from the culture medium triggered a novel Trp(156)-independent type of lateral E-cadherin-P-cadherin association. Notably, an antiparallel (adhesive) mode of interaction between these cadherins was negligible. The specificity of adhesive interaction was localized to the amino-terminal (EC1) domain of both cadherins. Thus, EC1 domain of classic cadherins exposes two determinants responsible for nonspecific lateral and cadherin type-specific adhesive dimerization.
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Kan, Anton, Ilenne Del Valle, Tim Rudge, Fernán Federici, and Jim Haseloff. "Intercellular adhesion promotes clonal mixing in growing bacterial populations." Journal of The Royal Society Interface 15, no. 146 (September 2018): 20180406. http://dx.doi.org/10.1098/rsif.2018.0406.
Повний текст джерелаАнотація:
Dense bacterial communities, known as biofilms, can have functional spatial organization driven by self-organizing chemical and physical interactions between cells, and their environment. In this work, we investigated intercellular adhesion, a pervasive property of bacteria in biofilms, to identify effects on the internal structure of bacterial colonies. We expressed the self-recognizing ag43 adhesin protein in Escherichia coli to generate adhesion between cells, which caused aggregation in liquid culture and altered microcolony morphology on solid media. We combined the adhesive phenotype with an artificial colony patterning system based on plasmid segregation, which marked clonal lineage domains in colonies grown from single cells. Engineered E. coli were grown to colonies containing domains with varying adhesive properties, and investigated with microscopy, image processing and computational modelling techniques. We found that intercellular adhesion elongated the fractal-like boundary between cell lineages only when both domains within the colony were adhesive, by increasing the rotational motion during colony growth. Our work demonstrates that adhesive intercellular interactions can have significant effects on the spatial organization of bacterial populations, which can be exploited for biofilm engineering. Furthermore, our approach provides a robust platform to study the influence of intercellular interactions on spatial structure in bacterial populations.
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Wilson, James G. "Adhesive Interactions in Hemopoiesis." Acta Haematologica 97, no. 1-2 (1997): 6–12. http://dx.doi.org/10.1159/000203654.
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Rosenfeld, Stephen J., and Harvey R. Gralnick. "Adhesive Interactions in Hemostasis." Acta Haematologica 97, no. 1-2 (1997): 118–25. http://dx.doi.org/10.1159/000203667.
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Pradyawong, Sarocha, Guangyan Qi, Meng Zhang, Xiuzhi S. Sun, and Donghai Wang. "Effect of pH and pH-Shifting on Adhesion Performance and Properties of Lignin-Protein Adhesives." Transactions of the ASABE 64, no. 4 (2021): 1141–52. http://dx.doi.org/10.13031/trans.14465.
Повний текст джерелаАнотація:
HighlightsLignin improved the wet adhesion strength of soy protein adhesives when pH shifted from 8.5 to 4.5.Lignin increased the water resistance of soy protein adhesives from 5% to 40% at pH 12.Lignin improved the thermal resistance of soy protein adhesives.pH and pH-shifting treatments led to property changes of lignin, soy protein, and lignin-soy protein.Abstract. Concerns about public health and the environment have created strong interest in developing alternative green products. The focus of this research was to study the effect of lignin on soy protein (SP) adhesives under different pH and pH-shifting treatments. Additionally, this research was designed to understand the consequence of pH and pH-shifting treatments on the adhesion performance of SP and lignin-SP (LSP) adhesives as well as the characteristics, solubility, glue line patterns, and physiochemical properties. To study the aggregation, soluble, and denatured stages of protein, the protein solutions were adjusted to pH 4.5, 8.5, and 12, respectively. In addition, the study of pH-shifting treatments was performed at pH 8.5 and 12 to unfold and denature the protein, respectively. The protein structure was then refolded by adjusting the pH to 4.5 in adhesive slurries. The adhesives presented good adhesion performance under dry conditions with wood failure in most treatments, while satisfactory wet adhesion performance was obtained at pH 4.5, 8.5 to 4.5, and 12. Shifting the pH from 8.5 to 4.5 increased the lignin-protein interaction and provided the best improvement in adhesion performance. Lignin strengthened the protein structure, increased the water resistance, and improved the thermal stability of SP adhesives. At an extremely high pH, the water resistance of SP increased from 5% to 40% with the addition of lignin. Lignin showed great potential for increasing the wet strength of SP adhesives. The SP and LSP properties and adhesion performance could be adjusted and improved by pH and pH-shifting processes. Lignin-SP interactions, water resistance, and glue line pattern proved to be significant factors contributing to adhesion performance. Keywords: Adhesive, Lignin, Lignin-protein interactions, pH, pH-Shifting, Protein.
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Lipke, Peter N., Jason M. Rauceo, and Albertus Viljoen. "Cell–Cell Mating Interactions: Overview and Potential of Single-Cell Force Spectroscopy." International Journal of Molecular Sciences 23, no. 3 (January 20, 2022): 1110. http://dx.doi.org/10.3390/ijms23031110.
Повний текст джерелаАнотація:
It is an understatement that mating and DNA transfer are key events for living organisms. Among the traits needed to facilitate mating, cell adhesion between gametes is a universal requirement. Thus, there should be specific properties for the adhesion proteins involved in mating. Biochemical and biophysical studies have revealed structural information about mating adhesins, as well as their specificities and affinities, leading to some ideas about these specialized adhesion proteins. Recently, single-cell force spectroscopy (SCFS) has added important findings. In SCFS, mating cells are brought into contact in an atomic force microscope (AFM), and the adhesive forces are monitored through the course of mating. The results have shown some remarkable characteristics of mating adhesins and add knowledge about the design and evolution of mating adhesins.
Дисертації з теми "Adhesive Interactions"
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Ren, Dakai. "Moisture-Cure Polyurethane Wood Adhesives: Wood/Adhesive Interactions and Weather Durability." Diss., Virginia Tech, 2010. http://hdl.handle.net/10919/29866.
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This project addresses two main subjects of moisture-cure polyurethane (PUR) wood adhesives: wood/PUR interactions and structure-property behavior emphasizing on weather durability. For these purposes, one simplified model PUR (MPUR) and three more commercially significant PURs (CPURs) with different hard segment contents were prepared. Separately, an early side project involved the synthesis of a 13C and 15N double-labeled polymeric methylenebis(phenylisocyanate) (pMDI) resin; this was used for the solid-state NMR characterization of isocyanate cure chemistry in wood bondline.
MPUR and a CPUR were employed to investigate whether wood/adhesive interactions influence PUR properties. Wood interactions significantly altered PUR hard/soft domain size distribution (atomic force microscopy, AFM), thermal transition temperatures (dynamic mechanical analyses, DMA), and urethane/urea hydrogen bonds (Fourier transform infrared spectroscopy, FTIR).
The effects of hard segment content on properties of PUR prepolymers, and cured PURs (films and wood composites) were studied. Hard segment content largely influenced the PURs’ molecular weights, viscosity, penetration, thermal transitions, and hard segment hydrogen bonds, but only slightly altered the dry (unweathered) bondline toughness.
Three accelerated weathering procedures were developed to evaluate CPUR bondline weather durability through mode-I fracture testing. Both hard segment content and weathering conditions were found to significantly influence the bondline weather durability. Among these weathering procedures, only one (VPSS) was able to effectively distinguish weather durability of PUR adhesives, and therefore it was selected for detailed structure-weather durability studies. PUR weather durability was found to correlate with its moisture sensitivity and hard segment softening temperature; both were provided by water-submersion DMA. Much attention was directed to the investigation of weather-induced PUR molecular changes. FTIR studies provided evidences of post-cure, hydrolytic degradation, and variation of urethane/urea hydrogen bonds. DMA presented weathering effects on PUR thermal properties. Special efforts have been made to correlate these analytical results with PUR weather durability.
A 13C and 15N double-labeled pMDI resin was synthesized and used for solid-state NMR characterization of isocyanate cure chemistry in wood bondline, particularly to detect the evidence of urethane formation. Rotational echo double resonance (REDOR) NMR clearly revealed the formation of urethane linkages, but largely overestimated their content.Ph. D.
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Cavenagh, James Durrell. "Adhesive interactions of leukaemic cells with endothelium." Thesis, Imperial College London, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.244210.
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Di, Fino Alessio. "Comparative approach to barnacle adhesive-surface interactions." Thesis, University of Newcastle upon Tyne, 2015. http://hdl.handle.net/10443/2838.
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Barnacles are considered to be one of the major marine fouling organisms. Their settlement behaviour has been investigated using mainly Balanus amphitrite as a model organism. To better understand the mechanisms involved during the colonisation of surfaces by cypris larvae we have investigated another species, B. improvisus, which is reported to have different surface preferences compared to B. amphitrite. This study aims to unravel the effects of surface physicochemical cues, in particular surface free energy (SFE), surface charge and elastic modulus on the settlement of cyprids of both species. The use of well-defined surfaces under controlled conditions further facilitates comparison of the results with B. amphitrite. Furthermore, since this phase of presettlement behaviour is characterised by temporary adhesive (footprint) deposition, considered to be fundamental to surface exploration and surface discrimination by cyprids, some of the chemistries used for the settlement assays were used to investigate temporary adhesive-surface interactions. Cyprids were exposed to a series of model surfaces, namely self-assembled monolayers (SAMs) of alkanethiols with varying end-groups, homogenously applied to gold-coated polystyrene Petri dishes. The settlement response was significantly higher on negatively charged SAMs and lower on positively charged surfaces, while intermediate settlement occurred on neutral SAMs. Furthermore, no effects were observed when data were plotted against surface free energy after 48 hr of exposure. Temporary adhesive on SAMs was investigated using imaging ellipsometry and atomic force microscopy. Relatively thick footprints with low wetting were found on positively charged surfaces. Settlement of both species was also low on these surfaces. Footprints were thinner and spread more on hydrophobic surfaces. The adhesion force of temporary adhesive measured with functionalised AFM tips was higher on hydrophobic and negatively charged surfaces for both species. Furthermore, PDMS-based surfaces were prepared varying the elastic modulus, keeping constant other parameters, settlement behaviour and strength of adhesion of juveniles and adults were tested. We conclude that cyprid settlement behaviour of both species is influenced more by surface charge than SFE under controlled conditions. The temporary adhesives (footprints) of the two species had a stronger affinity for hydrophobic surfaces. Contrary ii to previous reports, therefore, the settlement preferences and adhesive secretion of these two species are similar. Elastic modulus influences settlement, juveniles and adults removal of both species, although B. improvisus is more sensitive if compared with B. amphitrite. This finding will be important for understanding the mechanism of surface selection by cyprids and for the development of future antifouling technologies.
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Liu, Haijing. "Wet adhesion properties of oilseed proteins stimulated by chemical and physical interactions and bonding." Diss., Kansas State University, 2017. http://hdl.handle.net/2097/35774.
Повний текст джерелаАнотація:
Doctor of PhilosophyDepartment of Grain Science and Industry
X. Susan Sun
The ecological and public health liabilities related with consuming petroleum resources have inspired the development of sustainable and environmental friendly materials. Plant protein, as a byproduct of oil extraction, has been identified as an economical biomaterial source and has previously demonstrated excellent potential for commercial use. Due to the intrinsic structure, protein-based materials are vulnerable to water and present relatively low wet mechanical properties. The purpose of this study focuses on increasing protein surface hydrophobicity through chemical modifications in order to improve wet mechanical strength. However, most of the water sensitive groups (WSG), such as amine, carboxyl, and hydroxyl groups, are also attributed to adhesion. Therefore, the goal of this research is to reduce water sensitive groups to an optimum level that the modified soy protein presents good wet adhesion and wet mechanical strength. In this research, we proposed two major approaches to reduce WSG: 1). By grafting hydrophobic chemicals onto the WSGs on protein surface; 2). By interacting hydrophobic chemicals with the WSGs. For grafting, undecylenic acid (UA), a castor oil derivative with 11-carbon chain with a carboxyl group at one end and naturally hydrophobic, was used. Carboxyl groups from UA reacted with amine groups from protein and converted amines into ester with hydrophobic chains grafting on protein surface. The successful grafting of UA onto soy protein isolate (SPI) was proved by both Infrared spectroscopy (IR) and ninhydrin test. Wood adhesive made from UA modified soy protein had reached the highest wet strength of 3.30 ± 0.24 MPa with fiber pulled out, which was 65% improvement than control soy protein. Grafting fatty acid chain was verified to improve soy protein water resistance. For interaction approach, soy oil with three fatty acid chains was used to modify soy protein. Soy oil was first modified into waterborne polyurethanes (WPU) to improve its compatibility and reactivity with aqueous protein. The main forces between WPU and protein were hydrogen bonding, hydrophobic interactions, and physical entanglement. Our results showed that WPU not only increased protein surface hydrophobicity with its fatty acid chains but also enhanced the three-dimensional network structure in WPU-SPI adhesives. WPU modification had increased wet adhesion strength up to 3.81 ± 0.34 MPa with fiber pulled out compared with 2.01 ± 0.46 MPa of SPI. Based on IR and thermal behavior changes observed by DSC, it was inferred that a new crosslinking network formed between WPU and SPI. To exam if the UA and WPU technologies developed using soy protein are suitable for other plant proteins, we selected camelina protein because camelina oil has superior functional properties for jet fuels and polymers. Like soy protein, camelina protein is also highly water sensitive. However, simply applied UA and WPU to camelina protein following the same methods used for soy proteins, we did not obtain the same good adhesion results compared to what we achieved with soy protein. After protein structure analysis, we realized that camelina protein is more compact in structure compared to soy protein that made it weak in both dry and wet adhesion strength. Therefore, for camelina protein, we unfolded its compact structure with Polymericamine epichlorohydrine (PAE) first to improve flexible chains with more adhesion groups for future reaction with UA or WPU. PAE with charged groups interacted camelina protein through electrostatic interaction and promoted protein unfolding to increase reactivity within protein subunits and between protein and wood cells. Therefore, the wet adhesion strength of camelina protein was improved from zero to 1.30 ± 0.23 MPa, which met the industrial standard for plywood adhesives in terms of adhesion strength. Then the wet adhesion strength of camelina protein was further improved after applying UA and WPU into the PAE modified camelina protein. In addition, we also found PAE unfolding significantly improved the dry adhesion strength of camelina protein from 2.39 ± 0.52 to 5.39 ± 0.50 MPa with 100% wood failure on two-layer wood test. Camelina meal which is even more economical than camelina protein was studied as wood adhesive. Through a combination of PAE and laccase modification method, the wet adhesion strength of camelina meal was improved as high as 1.04 ± 0.19MPa, which also met industrial standards for plywood adhesives. The results of this study had proven successful modification of oilseed protein to increase water resistance and wet mechanical strength. We have gained in-depth understanding of the relationship between protein structure and wet adhesion strength. The successful modification of plant proteins meeting the industrial needs for bio-adhesives will promote the development of eco-friendly and sustainable materials.
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Zhao, Boxin Pelton Robert H. "The interactions of pressure sensitive adhesive with paper surfaces." *McMaster only, 2004.
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Taubenberger, Anna Verena. "Quantifying adhesive interactions between cells and extracellular matrix by single-cell force spectroscopy." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2009. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-24758.
Повний текст джерелаАнотація:
Interactions of cells with their environment regulate important cellular functions and are required for the organization of cells into tissues and complex organisms. These interactions involve different types of adhesion receptors. Interactions with extracellular matrix (ECM) proteins are mainly mediated by the integrin family of adhesion molecules. Situations in which integrin-ECM interactions are deregulated cause diseases and play a crucial role in cancer cell invasion. Thus, the mechanisms underlying integrin-binding and regulation are of high interest, particularly at the molecular level. How can cell-ECM interactions be studied? While there are several methods to analyze cell adhesion, few provide quantitative data on adhesion forces. One group, single-cell force spectroscopy (SCFS), quantifies adhesion at the single-cell level and can therefore differentiate the adhesive properties of individual cells. One implementation of SCFS is based on atomic force microscopy (AFM); this technique has been employed in the presented work. Advantageously AFM-SCFS combines high temporal and spatial cell manipulation, the ability to measure a large range of adhesion forces and sufficiently high-force resolution to allow the study of single-molecule binding events in the context of a living cell. Since individual adhesion receptors can be analyzed within their physiological environment, AFM-SCFS is a powerful tool to study the mechanisms underlying integrin-regulation. The presented work is split into six chapters. Chapter one gives background information about cell-ECM interactions. In chapter two, different adhesion assays are compared and contrasted. The theoretical Bell-Evans model which is used to interpret integrin-mediated cell adhesion is discussed in chapter three. Thereafter, the three projects that form the core of the thesis are detailed in chapters four through six. In the first project (chapter 4), α2β1-integrin mediated cell adhesion to collagen type I, the most abundant structural protein in vertebrates, was quantified using CHO cells. Firstly, α2β1-collagen interactions were investigated at the single-molecule level. Dynamic force spectroscopy permitted calculation of bond specific parameters, such as the bond dissociation rate koff (1.3 ± 1.3 sec-1) and the barrier width xu (2.3 ± 0.3 Å). Next, α2β1-integrin mediated cell adhesion to collagen type I was monitored over contact times between 0 and 600 sec. Thereby the kinetics of α2β1-integrin mediated interactions was explored and insights into the underlying binding mechanisms were gained. In the second project (chapter five), effects of cryptic integrin binding sites within collagen type I exerted on pre-osteoblasts were investigated. Collagen type I matrices were thermally denatured which lead to exposure of cryptic RGD (Arg-Gly-Asp)-motifs. As a consequence pre-osteoblasts enhanced their adhesion to denatured collagen. Compared to native collagen type I, adhesion to denatured collagen was mediated by a different set of integrins, including αv- and α5β1-integrins. Cells grown on denatured collagen showed enhanced spreading and motility, which correlated with increased focal adhesion kinase phosphorylation levels. Moreover, osteogenic differentiation kinetics and differentiation potential were increased on denatured collagen. The findings of this project open new perspectives for optimization of tissue engineering substrates. In the third part (chapter six), the effect of the fusion protein BCR/ABL, a hallmark of chronic myeloid leukemia, on adhesion of myeloid progenitor cells was studied. Adhesion between BCR/ABL transformed progenitor cells to bone marrow derived stromal cells and to different ECM proteins was quantitatively compared to that of control cells. The tyrosine kinase activity of BCR/ABL enhanced cell adhesion, which was blocked by imatinib mesylate, a drug interfering with BCR/ABL activity. BCR/ABL-enhanced adhesion correlated with increased β1-integrin cell surface concentrations. Since adhesion of leukemic cells to the bone marrow compartment is critical for the development of drug resistance, the reported results may provide a basis for optimized target therapies. In the three described projects AFM-based SCFS was applied to investigate early steps of integrin-mediated adhesion at the molecular level. Taken together, the results demonstrate that AFM-SCFS is a versatile tool that permits monitoring of cell adhesion from single-molecule interactions to the formation of more complex adhesion sites at the force levelInteraktionen zwischen Zellen und ihrer Umgebung sind maßgeblich an der Regulierung zellulärer Funktionen beteiligt und daher notwendig für die Organisation von Zellen in Geweben und komplexen Organismen. Zellinteraktionen mit der extrazellulären Matrix (EZM) werden hauptsächlich durch Integrine vermittelt. Situationen, in denen Integrin- EZM Interaktionen verändert sind, können Krankheiten verursachen und spielen zudem eine wichtige Rolle bei der Invasion von Krebszellen. Daher besteht ein großes Interesse darin, die molekularen Mechanismen, die Integrin-EZM Interaktionen regulieren, besser zu verstehen. Wie können Zell-EZM Interaktionen untersucht werden? Obwohl es mehrere Methoden gibt, mit denen Zelladhäsion untersucht werden kann, sind die wenigsten dazu geeignet, Zelladhäsionskräfte zu quantifizieren. Einzelzellspektroskopie erfasst die Adhäsionskräfte einzelner Zellen quantitativ und ermöglicht dadurch eine differenzierte Betrachtung der Adhäsion individueller Zellen. Eine Variante der Einzelzellspektroskopie basiert auf der Rasterkraftmikroskopie (AFM); diese Technik wurde in der vorliegenden Arbeit verwendet. Ein Vorteil von AFM- Einzelzellspektroskopie besteht darin, dass Zellen mit hoher zeitlicher und räumlicher Präzision manipuliert werden können. Zelladhäsionskräfte können zudem über einen großen Kraftbereich hinweg untersucht werden. Dabei ermöglicht es die hohe Kraftauflösung, einzelne Integrin-Ligandenbindungen in lebenden Zellen zu untersuchen. Die vorliegende Arbeit gliedert sich in sechs Kapitel. Kapitel eins gibt Hintergrundinformationen über Zell-EZM Wechselwirkungen. In Kapitel zwei werden verschiedene Adhäsionsassays einander gegenüber gestellt. Das theoretische Bell-Evans Modell, mit dessen Hilfe die gewonnenen Daten interpretiert wurden, wird in Kapitel drei diskutiert. Im Anschluss werden drei Projekte, welche das Herzstück dieser Doktorarbeit bilden, in Kapiteln vier bis sechs näher ausgeführt. Im ersten Projekt (Kapitel vier) wurde die Adhäsion von α2β1-Integrin exprimierenden CHO Zellen zu Kollagen I, dem häufigsten strukturellen Protein in Wirbeltieren, quantitativ untersucht. Zunächst wurden α2β1-Kollagen-Interaktionen auf Einzelmolekülebene analysiert. Mithilfe der dynamischen Kraftspektroskopie wurden für diese Bindung Dissoziationsrate koff (1.3 ± 1.3 sec-1) und Potentialbarrierenbreite xu (2.3 ± 0.3 Å) bestimmt. Daraufhin wurde die α2β1-vermittelte Adhäsion über einen Zeitraum von zehn Minuten untersucht. Dadurch konnten Einblicke in die Kinetik von α2β1-integrin vermittelter Zelladhäsion sowie in die zugrunde liegenden Regulationsmechanismen gewonnen werden. Im zweiten Projekt (Kapitel fünf) wurde die Rolle von kryptischen Integrin-Bindungsstellen in Kollagen I untersucht. Die zuvor verwendeten Kollagenoberflächen wurden thermisch denaturiert, wodurch versteckte RGD (Arg-Gly-Asp)-Sequenzen freigelegt wurden. Die partielle Denaturierung hatte- verglichen mit nativem Kollagen I- eine erhöhte Adhäsion von Präosteoblasten (MC3T3-E1) zur Folge, was auf das Binden zusätzlicher Integrine zurückgeführt wurde. Im Unterschied zu nativem Kollagen wurde die Zelladhäsion zu denaturiertem Kollagen I u.a. durch αv- and α5β1-Integrine vermittelt. Präosteoblasten zeigten verstärktes Zellspreiten sowie höhere Motilität auf denaturiertem Kollagen I; zudem wurde ein erhöhtes Differenzierungpotential der Präosteoblasten festgestellt. Die in diesem Projekt erhaltenen Einblicke bilden eine hilfreiche Basis für die Entwicklung optimierter Oberflächen für diverse Zell- und Gewebekulturanwendungen. Im dritten Projekt (Kapitel sechs) wurde der Einfluss des Fusionproteins BCR/ABL, charakteristisch für chronische myeloische Leukämie, auf die Adhäsion von myeloischen Vorläuferzellen untersucht. Dazu wurde die Adhäsion von BCR/ABL transformierten Vorläuferzellen (32D Zellen) bzw. Kontrollzellen zu Stromazellen (M2-10B4) sowie verschiedenen EZM Proteinen untersucht. BCR/ABL erhöhte die Zelladhäsion der myeloischen Vorläuferzellen signifikant. Dieser Effekt wurde durch die Zugabe von Imatinib, welches die Tyrosinkinaseaktivität von BCR/ABL inhibiert, aufgehoben. Die BCR/ABL-verstärkte Zelladhäsion korrelierte mit erhöhten β1-Integrin-konzentrationen. Da die Adhäsion von Leukämiezellen im Knockenmark bekanntermaßen kritisch für die Entwicklung von Resistenzen gegenüber verschiedenen Wirkstoffen ist, könnten die Ergebnisse dieser Studie eine Grundlage für die Entwicklung optimierter Target-Therapien sein. In den drei beschriebenen Projekten wurde AFM Einzelzellspektroskopie verwendet, um Integrin- vermittelte Adhäsion auf molekularer Ebene zu untersuchen. Die Ergebnisse zeigen, dass AFM-Einzelzellspektroskopie ein vielseitiges Werkzeug darstellt, das überaus geeignet dazu ist, Zelladhäsion- ausgehend von Einzelmolekülinteraktionen bis hin zur Entstehung komplexerer Adhäsionsstellen- auf der Kraftebene zu verfolgen
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Choudhury, Devapriya. "Functional implications of macromolecular recognition : assembly of adhesive pili and enzyme substrate interactions /." Uppsala : Swedish Univ. of Agricultural Sciences (Sveriges lantbruksuniv.), 2001. http://epsilon.slu.se/avh/2001/91-576-5820-X.pdf.
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Tucker, David. "Assessing the cellular and adhesive interactions in in vitro models of mantle cell lymphoma." Thesis, University of Plymouth, 2017. http://hdl.handle.net/10026.1/10235.
Повний текст джерелаАнотація:
Mantle cell lymphoma (MCL) is a rare lymphoproliferative disorder (LPD) that has very poor survival. Like other LPDs, the neoplastic cells of MCL have an intimate dependence upon accessory cells within haematopoietic tissues. Understanding and exploiting the tissue-relationships of the mantle cells may therefore lead to further new approaches to treatment. This study work has set out to construct an in vitro system to model relevant aspects of the tissue-dependent behaviour of the neoplastic mantle cells, seeking to establish the link between in vitro behaviour and clinical phenotype, and establishing the feasibility of this system to study the effects of different therapeutic interventions. The first experimental chapter employs relevant mouse and human stromal models to mirror the tissue environment of MCL in vivo. Testing relevant agents, the work establishes that the system can identify different behaviour between indolent and aggressive forms of MCL, and demonstrates a particular importance for CD40 ligand both in the proliferation and survival of the neoplastic mantle cells, but shows also how these effects are modulated by the soluble factors interleukin-4 (IL-4) and the toll-like receptor-9 ligand (TLR9-L). The second experimental chapter examines the adhesion molecules expressed on MCL cells. Considerable variation in the level of expression is observed between cases, but overall the cases express particularly high levels of the integrin receptors LFA-1 (detected by alpha chain CD11a) and VLA-4 (detected by alpha chain CD49d). Cases also showed a significant difference in overall adhesion and chemokine-receptor expression between cases that had either a nodal or leukaemic clinical pattern, although no single adhesion molecule was characteristic of clinical phenotype. The final experimental chapter looked at 3-D culture of MCL. Within tissues MCL grows in a 3-D rather than 2-D matrix and it is recognised that cells employ different forms of adhesion and migration within the different spatial environments. This chapter establishes the feasibility of growing cells in 3-D systems and looks at optimal conditions to preserve and examine the cellular characteristics of cells within a 3-D environment. Overall, this thesis demonstrates the feasibility and pathobiological relevance of ex vivo culture of MCL cells giving insights into the factors that drive MCL survival and proliferation and the correlation between in vitro behaviour and clinical phenotype. It is proposed that this work can be expanded to examine therapeutic interventions in the disorder.
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Masek, Lisa Christina. "The study of adhesive interactions between haemopoietic progenitor cells and bone marrow sinusoidal endothelial cells." Thesis, University of Southampton, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.242854.
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Kryworuchko, Marko Andrii. "Regulation of CD44 and its adhesive interactions with the extracellular matrix component, hyaluronan, by cytokines in normal and transformed human B lymphocytes." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape8/PQDD_0015/NQ46528.pdf.
Повний текст джерелаКниги з теми "Adhesive Interactions"
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Yu, Jing. Adhesive Interactions of Mussel Foot Proteins. Cham: Springer International Publishing, 2014. http://dx.doi.org/10.1007/978-3-319-06031-6.
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Rovensky, Yury A. Adhesive Interactions in Normal and Transformed Cells. Totowa, NJ: Humana Press, 2011. http://dx.doi.org/10.1007/978-1-61779-304-2.
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service), SpringerLink (Online, ed. Adhesive Interactions in Normal and Transformed Cells. Totowa, NJ: Springer Science+Business Media, LLC, 2011.
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Edward, Bittar E., Garrod D. R, North Alison J, and Chidgey Martin A. J, eds. The adhesive interaction of cells. Stamford, Conn: JAI Press Inc., 1999.
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L, Gordon J., ed. Vascular endothelium: Interactions with circulating cells. Amsterdam: Elsevier, 1991.
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J, Nelson W., ed. Membrane protein-cytoskeleton interactions. San Diego: Academic Press, 1996.
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Russell, Stevenson Bruce, Gallin Warren J, and Paul David Louis, eds. Cell-cell interactions: A practical approach. Oxford: IRL Press at Oxford University Press, 1992.
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Whittard, John Edward. Heterocyclic interactions between families of cell-adhesion molecules. Manchester: University of Manchester, 1996.
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Bjerketorp, Joakim. Novel adhesive proteins of pathogenic Staphylococci and their interaction with host proteins. Uppsala: Swedish University of Agricultural Sciences, 2004.
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P, Fleming Tom, ed. Cell-cell interactions: A practical approach. 2nd ed. Oxford: Oxford University Press, 2002.
Знайти повний текст джерелаЧастини книг з теми "Adhesive Interactions"
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Rovensky, Yury A. "Intercellular Adhesive Interactions." In Adhesive Interactions in Normal and Transformed Cells, 185–211. Totowa, NJ: Humana Press, 2011. http://dx.doi.org/10.1007/978-1-61779-304-2_9.
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Dejana, Elisabetta, Lindsey Needham, and John Gordon. "Endothelial Cell Adhesive Interactions." In Endothelial Cell Dysfunctions, 153–68. Boston, MA: Springer US, 1992. http://dx.doi.org/10.1007/978-1-4899-0721-9_9.
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Frojmovic, M. M. "Platelet Biorheology: Adhesive Interactions in Flow." In Handbook of Platelet Physiology and Pharmacology, 315–41. Boston, MA: Springer US, 1999. http://dx.doi.org/10.1007/978-1-4615-5049-5_14.
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Smith, C. W., O. Abbassi, S. B. Shappell, D. C. Anderson, L. V. McIntire, and T. K. Kishimoto. "Adhesive Interactions of Neutrophils with Endothelial Cells." In Host Defense Dysfunction in Trauma, Shock and Sepsis, 431–36. Berlin, Heidelberg: Springer Berlin Heidelberg, 1993. http://dx.doi.org/10.1007/978-3-642-77405-8_50.
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Gordon, M. Y., D. Clarke, C. R. Dowding, and M. Siczkowski. "Adhesive Interactions in the Regulation of Haemopoiesis." In Modern Trends in Human Leukemia IX, 93–96. Berlin, Heidelberg: Springer Berlin Heidelberg, 1992. http://dx.doi.org/10.1007/978-3-642-76829-3_17.
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Rovensky, Yury A. "Introduction." In Adhesive Interactions in Normal and Transformed Cells, 1–5. Totowa, NJ: Humana Press, 2011. http://dx.doi.org/10.1007/978-1-61779-304-2_1.
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Rovensky, Yury A. "Conclusions." In Adhesive Interactions in Normal and Transformed Cells, 213–15. Totowa, NJ: Humana Press, 2011. http://dx.doi.org/10.1007/978-1-61779-304-2_10.
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Rovensky, Yury A. "The Extracellular Matrix." In Adhesive Interactions in Normal and Transformed Cells, 7–12. Totowa, NJ: Humana Press, 2011. http://dx.doi.org/10.1007/978-1-61779-304-2_2.
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Rovensky, Yury A. "Cytoskeleton." In Adhesive Interactions in Normal and Transformed Cells, 13–35. Totowa, NJ: Humana Press, 2011. http://dx.doi.org/10.1007/978-1-61779-304-2_3.
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Rovensky, Yury A. "Pseudopodia and Adhesion Structures." In Adhesive Interactions in Normal and Transformed Cells, 37–56. Totowa, NJ: Humana Press, 2011. http://dx.doi.org/10.1007/978-1-61779-304-2_4.
Повний текст джерелаТези доповідей конференцій з теми "Adhesive Interactions"
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King, Michael R. "Cell-Surface Adhesive Interactions in Microchannels and Microvessels." In ASME 2003 1st International Conference on Microchannels and Minichannels. ASMEDC, 2003. http://dx.doi.org/10.1115/icmm2003-1011.
Повний текст джерелаАнотація:
Adhesive interactions between white blood cells and the interior surface of the blood vessels they contact is important in inflammation and in the progression of heart disease. Parallel-plate microchannels have been useful in characterizing the strength of these interactions, in conditions that are much simplified over the complex environment these cells experience in the body. Recent computational and experimental work by several laboratories have attempted to bridge this gap between behavior observed in flow chamber experiments, and cell-surface interactions observed in the microvessels of anesthetized animals.
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Imai, Yohsuke, Hitoshi Kondo, Young Ho Kang, Takuji Ishikawa, Chwee Teck Lim, and Takami Yamaguchi. "A Numerical Model of Adhesion Property of Malaria Infected Red Blood Cells in Micro Scale Blood Flows." In ASME 2009 Summer Bioengineering Conference. American Society of Mechanical Engineers, 2009. http://dx.doi.org/10.1115/sbc2009-206456.
Повний текст джерелаАнотація:
Infection by malaria parasite changes mechanical properties of red blood cells (RBCs). Infected red blood cells (IRBCs) lose the deformability but also develop the ability to cytoadhere and rosetting. These outcomes can lead to microvascular blockage [1]. The stiffness of IRBCs [2] and its effects on the flow in micro channels [3] were studied with recent experimental techniques. The cytoadherence and rosetting properties of IRBCs have also been studied experimentally. The cytoadherence is mediated by the interaction of the parasite protein PfEMP1 with several endothelial adhesion molecules, such as CD36, intercellular adhesion molecule-1 (ICAM-1), P-selectin, and vascular cell adhesion molecule-1 (VCAM-1) [4]. In particular, the ligand-receptor interaction between PfEMP1 and CD36 shows tight adhesion [5]. Microvascular blockage may be a hemodynamic problem, involving the interactions between IRBCs, healthy RBCs (HRBCs) and endothelial cells (ECs) in flowing blood, but however experimental techniques have several limitations to this topic. First, it is still difficult to observe the RBC behavior interacting with many other cells even with the recent confocal microscopy. Second, the three-dimensional information on flow field is hardly obtained. Third, capillaries in human body are circular channels with complex geometry, but such complex channels cannot be created in micro scale. Instead, numerical modeling can overcome these problems. We presented a two-dimensional hemodynamic model involving adhesive interactions [6]. In this paper, we propose a three-dimensional model of the adhesive interactions for micro scale hemodynamics in malaria infection.
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Schoeller, Harry, Aaron Knobloch, Hua Xia, David Shaddock, Chris Kapusta, Kevin Durocher, and Jungyun Cho. "Adhesive Tiecoat/Polyimide Interactions in High Temperature Flex Packaging." In ASME 2007 InterPACK Conference collocated with the ASME/JSME 2007 Thermal Engineering Heat Transfer Summer Conference. ASMEDC, 2007. http://dx.doi.org/10.1115/ipack2007-33419.
Повний текст джерелаАнотація:
The high temperature reliability of flex-based Cu/tiecoat/polyimide structures was evaluated through finite element simulation and experimental approach. This study is part of an effort to characterize and optimize polyimide flex as a substrate material for electronics packages rated to greater than 204°C. The peel strength of several common adhesion metals (Ti, Cr, Ni, Cu) on Kapton E was quantified at room temperature and after high temperature storage in inert and highly oxidizing environments. These results were used in tandem with thermal-mechanical simulations to characterize the behavior of several tiecoat materials. Experimental results showed diminished peel strengths of both the Ti and Cr after a 100-hour 250°C heat treatment in air. However when annealed in an inert N2 environment at 250°C for 100 hours, Cr, Ni, and Ti retained their as-sputtered peel strength. Ni and Cu exhibited lower mechanical stresses in the simulation; however, their relatively low reactivity limits their adhesion strength at the interface in oxidizing environments. To further understand the origin of the thermal-mechanical stress, the effect of mismatched CTE was compared to mismatched elastic modulus. Both properties were found to contribute to stress generation; however elastic modulus mismatches had a much greater influence on the overall magnitude of the stress. Through experimentation and FEA analysis this study aims to develop a flexed-based high temperature packaging solution and to shed light onto high temperature tiecoat/polyimide interactions.
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KHAMMASSI10.12783/asc36/35835, SABRINE, and MOSTAPHA TARFAOUI. "ENHANCED FRACTURE TOUGHNESS OF ADHESIVE JOINTS WITH DOPING EPOXY BY GRAPHENE NANOPLATELETS." In Thirty-sixth Technical Conference. Destech Publications, Inc., 2021. http://dx.doi.org/10.12783/asc36/35835.
Повний текст джерелаАнотація:
It is necessary to enhance the mechanical properties of adhesives to replace conventional joint methods with adhesive bonding. Epoxy in its pure state often suffers catastrophic damage due to its obvious brittleness and low fracture toughness. In this study, the double cantilever beam (DCB - Mode I) was used to characterize the fracture toughness of graphene/DGEBA-epoxy nanocomposite adhesive in bonded aluminium alloy joints and bonded composite joints. Adhesives based on an epoxy adhesive DGEBA (Bisphenol A diglycidyl ether) reinforced with two percentages (1wt.% and 2wt.%) of graphene nanoplatelets (GNP) were prepared. In this study, one shows that the fracture toughness of adhesive nanocomposites was significantly better than neat epoxy-bonded adhesives. Both types of joints contain graphene resulting in increased fracture toughness. Therefore, the maximum fracture toughness was observed until the GNP reached 1wt.%, and then it began to decrease, but it is still higher than that of the pure adhesive joint. On the other hand, this work aims to determine the influence of interfacial interactions on the behavior of enhanced bonded joints and how graphene nanoplatelets can enhance the rigidity of the interface between the substrate and the adhesive. In addition, a numerical study using ABAQUS was performed and compared with the experiments performed on DCB. For the modeling of the damage in an assembly joint, the Cohesive Zone Model (CZM) was used for the fracture behavior of the adhesive.
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Bastida, E., and L. Almirall. "EFFECTS OF 13-H0DE AND HETEs ON TUMOR CELL/ENDOTHELIAL CELL INTERACTIONS." In XIth International Congress on Thrombosis and Haemostasis. Schattauer GmbH, 1987. http://dx.doi.org/10.1055/s-0038-1643947.
Повний текст джерелаАнотація:
We and others reported that endothelial cells (ECs) convert linoleic acid into 13-hydroxyoctadecadienoic acid (13-H0DE) under basal conditions, and arachidonic acid into 15-hydroxyeicosatet-raenoic acid (15-HETE) following stimulation (1,2). We also reported that lipoxygenase metabolism influenced platelet (PLT) interactions with ECs, tumor cells (TCs) and extracellular matrix (BM) (1,3,4). Thus, we performed studies to determine i) if TCs also produce 13-H0DE and HETEs, and ii) the effect of TC and EC 13-H0DE and HETEs synthesis on TC/EC adhesion. We measured i) the ratios of 13-H0DE:HETE in 5TC lines, under basal and stimulated conditions, in metastatic and non-metastatic TCs of the same cell line, and TCs treated with salicylate (SAL) or dipyridamole (DIP), and ii) their relationships with TC adhesion to ECs and BM. 13-H0DE and HETEs were assayed by HPLC. TC adhesion was assayed as the # radiolabelled TCs adherent to ECs or BM. cAMP was assayed by RIA. Under basal conditions, TCs produced 13-H0DE and HETEs, the intracellular ratio of which markedly affected their adhesivity; e.g. the least adhesive TC (U87MG glioblastoma) produced 21Xs more 13-H0DE than HETE’s, while a more adhesive TC (A549, adenocarcinoma) produced 4Xs more HETEs than 13-H0DE. Non-metastatic TCs preferentially produced 13-H0DE while metastatic TCs of the same cell line, produced HETEs. Stimulation of TCs or ECs decreased 13-H0DE, and increased HETE synthesis and TC/EC adhesion. Inhibiting intracellular 13-H0DE synthesis in either TCs or EC (SAL RX) enhanced TC/EC and TC/BM adhesion. Enhancing 13-H0DE synthesis by elevating cAMP (DIP RX) inhibited TC/EC and TC/BM adhesion. We conclude that 1) in vitro TCs produce 13-H0DE and HETEs, 2) the ratio of 13-H0DE:HETEs in TCs and ECs affects their adhesivity; and 3) the ratio of intracellular 13-H0DE:HETEs depends upon cAMP. This suggests that 13-H0DE:HETE ratios in TCs and ECs influence the adhesion process in the pathogenesis of thrombosis and metastasis in vivo. (1) Buchanan et al, JBC 30:1985. (2) Hopkins et al, JBC 29:1984. (3) Bastida et al, Int. J. Cane. 1987. (4) Buchanan et al, Prost. Leuk. Med., 1986.
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Nachman, R. L., R. L. Silverstein, and A. S. Asch. "THROMBOSPONDIN: CELL BIOLOGY OF AN ADHESIVE GLYCOPROTEIN." In XIth International Congress on Thrombosis and Haemostasis. Schattauer GmbH, 1987. http://dx.doi.org/10.1055/s-0038-1644653.
Повний текст джерелаАнотація:
Thrombospondin (TSP), a multifunctional 450 KD glycoprotein is a secretory product of thrombin stimulated platelets. It is a major component of the platelets alpha granule constituting approximately 3% of total platelet protein. Thrombospondin does not circulate in appreciable concentrations ∽0 100 ng/ml); however, the tissue distribution is broad. In addition to its expression on the membrane of activated platelets, the protein is synthesized by fibroblasts endothelial cells, glial cell smooth muscle cells alveolar pneumocytes mononuclear phagocytes and various tumor cells. TSP is a major constituent of the extracellular matrix and has been demonstrated in the vessel wall, basement membrane and glandular connective tissue. Fibroblasts, smooth muscle cells and endothelial cells in tissue culture incorporate TSP into the extracellular matrix. Matrix TSP is under cell-cycle regulatory control. Mesenchymal cells in the proliferative phase synthesize greater amounts of TSP than non growing cells. Platelet derived growth factor induces smooth muscle cell and glial cell synthesis of TSP. Atheromatous lesions contain increased amounts of TSP compared to normal vessels emphasizing the potential role of TSP in the interaction of proliferating cells with the matrix. TSP binds specifically, saturably, and reversibly to mouse peritoneal macrophages and to cells of the monocyte-like human cell line U937. Binding was time dependent and was optimal in the presence of both Ca++ and Mg++. PMA stimulated U937 cells and activated macrophages bound TSP to an equivalent extent as resting cells. The TSP binding site on the surface of U937 cells and peripheral blood monocytes mediates the adhesive interaction between these cells and thrombin-stimulated platelets. Using a sensitive rosetting assay we found that monocytes were not rosetted by resting platelets while >90% were rosetted by thrombin-stimulated platelets. Monoclonal and polyclonal anti-TSP antibodies markedly inhibited rosetting as did TSP itself. Antifibronectin or non-immune control antibodies did not inhibit rosetting, nor did fibronectin, fibrinogen, the fibronectinadhesion tetrapeptide arg-gly-asp-ser (RGDS), or heparin. The TSP membrane receptor, an 88 KD glycoprotein, formely known as GPIV has been identified in platelets, endothelial cells, monocytes and a variety of tumor cells. TSP may thus serve as a molecular bridge linking activated platelets with monocytes at sites of early vascular injury. Such interactions involving the TSP receptor complex may be of critical importance in the regulation of thrombosis and the initiation of atherosclerosis.
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Sarvestani, Alireza. "A Theoretical Analysis for the Effect of Substrate Elasticity on Cellular Adhesion." In ASME 2010 First Global Congress on NanoEngineering for Medicine and Biology. ASMEDC, 2010. http://dx.doi.org/10.1115/nemb2010-13311.
Повний текст джерелаАнотація:
Cell behavior is mediated by variety of physiochemical properties of extracellular matrix (ECM). Material composition, surface chemistry, roughness, and distribution pattern of cell adhesive proteins are among the ECM properties which are known to modulate various cellular physiological functions. Mechanical stiffness of ECM in particular is found to be a major regulator for multiple aspects of cellular function. Experiments show that cells in general, exhibit an apparent adhesion preference for stiffer substrates with a larger projected spread area with increasing the substrate stiffness. In addition, it seems that the effect of substrates elasticity is strongly coupled with adhesivity of the substrate; on relatively stiff substrates the spread area of the cells exhibits strong biphasic dependence to the changes in ligand density, whereas on soft substrates their limited spreading is much less sensitive to the density of surface ligands. This study aims to propose a theoretical basis for the interplay between substrate elasticity and cellular adhesion, using an equilibrium thermodynamic model. Within this framework, the equilibrium contact area is assumed to ensure minimization of the free energy contributed by interfacial adhesive and repulsive interactions between the membrane and substrate as well as the deformation of cell and substrate. Hence, this thermodynamic model overlooks the contribution of intracellular signaling or actively regulated cytoskeleton and assumes that cell adhesion is solely a result of the balance between the membrane-substrate repulsive potentials, stored elastic energy, binding enthalpy, and mixing entropy of mobile receptors. The predictions of this purely mechanistic model for cell adhesion qualitatively follow the experimental results featuring the variation of cell spread area on compliant bio-adhesive substrates. This suggests that the mechanistic pathways inherent to membrane-substrate interactions may be equally important as intracellular signaling pathways to mediate the cellular adhesion.
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Sarvestani, Alireza. "Kinetics of Membrane Spreading on Compliant Bio-Adhesive Substrates." In ASME 2010 First Global Congress on NanoEngineering for Medicine and Biology. ASMEDC, 2010. http://dx.doi.org/10.1115/nemb2010-13321.
Повний текст джерелаАнотація:
The contact formation between cell membrane and a bio-adhesive substrate is driven by binding between transmembrane mobile receptors (e.g., integrin) and complementary ligand molecules on the substrate (fibronectin, collagen, etc.) This short range specific adhesion is alleviated by a phalanx of interfacial non-specific forces. In addition to cell-substrate interfacial interactions, cell adhesion can be mediated by a wide range of substrate physiochemical properties. In particular, mechanical stiffness of the substrate has been recognized as one of the major regulators for bio-adhesion. Cells in general, exhibit an apparent adhesion preference for stiffer substrates and switch from a round to spread morphology as the substrate stiffness increases. Understanding the mechano-chemical pathways mediating the interplay between the substrate properties and cell behavior could be critical for effective performance of synthetic biomaterials in tissue engineering applications. In this study, we consider the effect of substrate elasticity on the dynamics of membrane spreading and growth of focal adhesion zone. The formation and growth of the focal adhesion points during the early stage of adhesion process is a result of spontaneous spreading of membrane on the substrate. This can be considered as a non-equilibrium kinetic process which is controlled by the diffusibility of receptor molecules. In order to study the effect of substrate elasticity on the kinetics of membrane-substrate association, receptors are assumed as ideal solute particles laterally diffusing within the plane of the membrane until they are stabilized through association with their complementary ligands which are immobilized on the surface of a compliant substrate. Considering different mechanical stiffness for the substrates, the displacement and speed of spreading at the edge of adhesion zone are predicted as a function of time. Results show that decreasing the stiffness of bio-adhesive substrates reduces the rate of membrane spreading, due to a weaker thermodynamic force which drives the membrane-substrate association. This mechanism restrains the growth of focal adhesion zones on compliant substrates and can be considered as a reason for smaller spread area of the cells after stabilization of adhesion.
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Wernik, Jacob M., and Shaker A. Meguid. "Multiscale Modeling of Nano-Reinforced Structural Adhesive Bonds." In ASME 2013 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/imece2013-64978.
Повний текст джерелаАнотація:
In this work, the mechanical properties of carbon nanotube reinforced structural adhesive bonds are investigated both theoretically and experimentally. The theoretical investigations employ a novel multiscale modeling technique that integrates governing atomistic constitutive laws in a continuum framework. This technique takes into account the discrete nature of the atomic interactions at the nanometer length scale and the interfacial characteristics of the nanotube and the surrounding polymer matrix. Appropriate formulations are developed to allow for the atomistic-based continuum modelling of nano-reinforced structural adhesive bonds on the basis of a nanoscale representative volume element that accounts for the nonlinear behaviour of its constituents; namely, the reinforcing carbon nanotube, the surrounding adhesive and their interface. This model is used to evaluate the constitutive response of carbon nanotubes with varied chiral indices. The newly developed representative volume element is then used with analytical micromechanical modeling techniques to investigate the homogeneous and dispersion of the reinforcing element into the adhesive considered upon the linear elastic properties.
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Larson, Lyndon, Yin Tang, Adriana Zambova, Cassandra Hale, Sushumna Iruvanti, Taryn Davis, Hai Longworth, and Richard Langlois. "Fundamental investigation of lid interactions with TIM1 and adhesive materials for advanced flip chip packaging." In 2015 IEEE 65th Electronic Components and Technology Conference (ECTC). IEEE, 2015. http://dx.doi.org/10.1109/ectc.2015.7159873.
Повний текст джерелаЗвіти організацій з теми "Adhesive Interactions"
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Frihart, Charles R. Adhesive interactions with wood. Madison, WI: U.S. Department of Agriculture, Forest Service, Forest Products Laboratory, 2004. http://dx.doi.org/10.2737/fpl-gtr-149.
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Lillard. Jr, James W. CXCL13-CXCR5 Interaction and Prostate Cancer Cell Firm Adhesion and Bone Metastasis. Fort Belvoir, VA: Defense Technical Information Center, September 2007. http://dx.doi.org/10.21236/ada484348.
Повний текст джерела
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Morrison, Mark, Joshuah Miron, Edward A. Bayer, and Raphael Lamed. Molecular Analysis of Cellulosome Organization in Ruminococcus Albus and Fibrobacter Intestinalis for Optimization of Fiber Digestibility in Ruminants. United States Department of Agriculture, March 2004. http://dx.doi.org/10.32747/2004.7586475.bard.
Повний текст джерелаАнотація:
Improving plant cell wall (fiber) degradation remains one of the highest priority research goals for all ruminant enterprises dependent on forages, hay, silage, or other fibrous byproducts as energy sources, because it governs the provision of energy-yielding nutrients to the host animal. Although the predominant species of microbes responsible for ruminal fiber degradation are culturable, the enzymology and genetics underpinning the process are poorly defined. In that context, there were two broad objectives for this proposal. The first objective was to identify the key cellulosomal components in Ruminococcus albus and to characterize their structural features as well as regulation of their expression, in response to polysaccharides and (or) P AA/PPA. The second objective was to evaluate the similarities in the structure and architecture of cellulosomal components between R. albus and other ruminal and non-ruminal cellulolytic bacteria. The cooperation among the investigators resulted in the identification of two glycoside hydrolases rate-limiting to cellulose degradation by Ruminococcus albus (Cel48A and CeI9B) and our demonstration that these enzymes possess a novel modular architecture specific to this bacterium (Devillard et al. 2004). We have now shown that the novel X-domains in Cel48A and Cel9B represent a new type of carbohydrate binding module, and the enzymes are not part of a ceiluiosome-like complex (CBM37, Xu et al. 2004). Both Cel48A and Cel9B are conditionally expressed in response to P AA/PPA, explaining why cellulose degradation in this bacterium is affected by the availability of these compounds, but additional studies have shown for the first time that neither PAA nor PPA influence xylan degradation by R. albus (Reveneau et al. 2003). Additionally, the R. albus genome sequencing project, led by the PI. Morrison, has supported our identification of many dockerin containing proteins. However, the identification of gene(s) encoding a scaffoldin has been more elusive, and recombinant proteins encoding candidate cohesin modules are now being used in Israel to verify the existence of dockerin-cohesin interactions and cellulosome production by R. albus. The Israeli partners have also conducted virtually all of the studies specific to the second Objective of the proposal. Comparative blotting studies have been conducted using specific antibodies prepare against purified recombinant cohesins and X-domains, derived from cellulosomal scaffoldins of R. flavefaciens 17, a Clostridium thermocellum mutant-preabsorbed antibody preparation, or against CbpC (fimbrial protein) of R. albus 8. The data also suggest that additional cellulolytic bacteria including Fibrobacter succinogenes S85, F. intestinalis DR7 and Butyrivibrio fibrisolvens Dl may also employ cellulosomal modules similar to those of R. flavefaciens 17. Collectively, our work during the grant period has shown that R. albus and other ruminal bacteria employ several novel mechanisms for their adhesion to plant surfaces, and produce both cellulosomal and non-cellulosomal forms of glycoside hydrolases underpinning plant fiber degradation. These improvements in our mechanistic understanding of bacterial adhesion and enzyme regulation now offers the potential to: i) optimize ruminal and hindgut conditions by dietary additives to maximize fiber degradation (e.g. by the addition of select enzymes or PAA/PPA); ii) identify plant-borne influences on adhesion and fiber-degradation, which might be overcome (or improved) by conventional breeding or transgenic plant technologies and; iii) engineer or select microbes with improved adhesion capabilities, cellulosome assembly and fiber degradation. The potential benefits associated with this research proposal are likely to be realized in the medium term (5-10 years).