Artículos de revistas: "Degraded adhesion"

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Nakagawa, Ichiro, Hiroaki Inaba, Taihei Yamamura, Takahiro Kato, Shinji Kawai, Takashi Ooshima y Atsuo Amano. "Invasion of Epithelial Cells and Proteolysis of Cellular Focal Adhesion Components by Distinct Types of Porphyromonas gingivalis Fimbriae". Infection and Immunity 74, n.º 7 (julio de 2006): 3773–82. http://dx.doi.org/10.1128/iai.01902-05.

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ABSTRACT Porphyromonas gingivalis fimbriae are classified into six types (types I to V and Ib) based on the fimA genes encoding FimA (a subunit of fimbriae), and they play a critical role in bacterial interactions with host tissues. In this study, we compared the efficiencies of P. gingivalis strains with distinct types of fimbriae for invasion of epithelial cells and for degradation of cellular focal adhesion components, paxillin, and focal adhesion kinase (FAK). Six representative strains with the different types of fimbriae were tested, and P. gingivalis with type II fimbriae (type II P. gingivalis) adhered to and invaded epithelial cells at significantly greater levels than the other strains. There were negligible differences in gingipain activities among the six strains; however, type II P. gingivalis apparently degraded intracellular paxillin in association with a loss of phosphorylation 30 min after infection. Degradation was blocked with cytochalasin D or in mutants with fimA disrupted. Paxillin was degraded by the mutant with Lys-gingipain disrupted, and this degradation was prevented by inhibition of Arg-gingipain activity by Nα-p-tosyl-l-lysine chloromethyl ketone. FAK was also degraded by type II P. gingivalis. Cellular focal adhesions with green fluorescent protein-paxillin macroaggregates were clearly destroyed, and this was associated with cellular morphological changes and microtubule disassembly. In an in vitro wound closure assay, type II P. gingivalis significantly inhibited cellular migration and proliferation compared to the cellular migration and proliferation observed with the other types. These results suggest that type II P. gingivalis efficiently invades epithelial cells and degrades focal adhesion components with Arg-gingipain, which results in cellular impairment during wound healing and periodontal tissue regeneration.

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Rajshankar, Dhaarmini, Gregory P. Downey y Christopher A. McCulloch. "IL‐1β enhances cell adhesion to degraded fibronectin". FASEB Journal 26, n.º 11 (24 de julio de 2012): 4429–44. http://dx.doi.org/10.1096/fj.12-207381.

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YAMADA, Tatsuhiko, Yanhong HU y Hirokuni ONO. "Condensation Reaction of Degraded Lignocellulose during Wood Liquefaction in the Presence of PolyhydricAlcohols". Journal of The Adhesion Society of Japan 37, n.º 12 (2001): 471–78. http://dx.doi.org/10.11618/adhesion.37.471.

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Tsai, S.-W., J.-F. Fang, C.-L. Yang, J.-H. Chen, L.-T. Su y S.-H. Jan. "Preparation and Evaluation of a Hyaluronate-Collagen Film for Preventing Post-Surgical Adhesion". Journal of International Medical Research 33, n.º 1 (febrero de 2005): 68–76. http://dx.doi.org/10.1177/147323000503300106.

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Post-surgical adhesion occurs when fibrous strands of scar tissue form, leading to the abnormal joining of anatomical structures. Patients undergoing abdominal surgery are at risk of the complications associated with intraperitoneal adhesions. Hyaluronic acid (HA) is a biocompatible, biodegradable and non-toxic natural polymer, which is gaining popularity as a barrier agent for preventing post-surgical adhesions. As HA is water-soluble and rapidly degraded in vivo, chemical modification is required to produce a non-soluble sheet that might be used to prevent tissue adhesion. We developed a range of biocompatible cross-linked HA-collagen composites and then evaluated them in a rat model of post-surgical adhesion. The results showed that cross-linked HA-collagen was almost totally resistant to hyaluronidase digestion. HA-collagen membranes induced minimal tissue reactions and were bioresorbed within 14 days post-surgery. These results suggest that cross-linked HA-collagen membrane may be a valuable anti-adhesion material to prevent post-surgical intraperitoneal adhesion.

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5

Carragher, Neil O., Bodo Levkau, Russell Ross y Elaine W. Raines. "Degraded Collagen Fragments Promote Rapid Disassembly of Smooth Muscle Focal Adhesions That Correlates with Cleavage of Pp125FAK, Paxillin, and Talin". Journal of Cell Biology 147, n.º 3 (1 de noviembre de 1999): 619–30. http://dx.doi.org/10.1083/jcb.147.3.619.

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Active matrix metalloproteinases and degraded collagen are observed in disease states, such as atherosclerosis. To examine whether degraded collagen fragments have distinct effects on vascular smooth muscle cells (SMC), collagenase-digested type I collagen was added to cultured human arterial SMC. After addition of collagen fragments, adherent SMC lose their focal adhesion structures and round up. Analysis of components of the focal adhesion complex demonstrates rapid cleavage of the focal adhesion kinase (pp125FAK), paxillin, and talin. Cleavage is suppressed by inhibitors of the proteolytic enzyme, calpain I. In vitro translated pp125FAK is a substrate for both calpain I– and II–mediated processing. Mapping of the proteolytic cleavage fragments of pp125FAK predicts a dissociation of the focal adhesion targeting (FAT) sequence and second proline-rich domain from the tyrosine kinase domain and integrin-binding sequence. Coimmunoprecipitation studies confirm that the ability of pp125FAK to associate with paxillin, vinculin, and p130cas is significantly reduced in SMC treated with degraded collagen fragments. Further, there is a significant reduction in the association of intact pp125FAK with the cytoskeletal fraction, while pp125FAK cleavage fragments appear in the cytoplasm in SMC treated with degraded collagen fragments. Integrin-blocking studies indicate that integrin-mediated signals are involved in degraded collagen induction of pp125FAK cleavage. Thus, collagen fragments induce distinct integrin signals that lead to initiation of calpain-mediated cleavage of pp125FAK, paxillin, and talin and dissolution of the focal adhesion complex.

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Leimgruber, Simon, Wolfgang Kern, Roman Hochenauer, Michael Melmer, Armin Holzner y Gregor Trimmel. "RUBBER–BRASS ADHESION LAYER ANALYSIS USING THE OLEFIN-METATHESIS METHOD". Rubber Chemistry and Technology 88, n.º 2 (1 de junio de 2015): 219–33. http://dx.doi.org/10.5254/rct.14.85946.

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ABSTRACT The investigation of the adhesion layer between rubber and brass-coated steel wires is a challenging task due to its strong bonding. We explore the possibilities of olefin-metathesis as a method to degrade the cross-linked rubber network without destroying the adhesion layer. Using a ruthenium catalyst and 1-octene as a co-reactant, different types of rubber—natural rubber, acrylonitrile–butadiene rubber, and styrene–butadiene rubber—can be degraded into soluble fragments. The uncovered adhesion layers can be subsequently analyzed with common analytical methods such as optical microscopy, focusvariation microscopy, and scanning electron microscopy. The revealed surface structures are discussed considering the observed pull-out forces. In a second series, the influence of common additives—cobalt salt, silica, and a resin system—on the metathesis reaction is investigated.

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Clark, S. K. "Loss of Adhesion of Cord-Rubber Composites in Aircraft Tires". Tire Science and Technology 14, n.º 1 (1 de enero de 1986): 33–43. http://dx.doi.org/10.2346/1.2148764.

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Abstract The degradation of adhesive strength between plies in aircraft tires was studied as a function of aging temperature, time, and environment. Adhesive strength degraded much faster than the cord tensile strength under the aging conditions used. Adhesive strength degraded faster in air than in nitrogen during the long-term aging. A 50% loss in adhesive strength is suggested as a reasonable critical value in determining tire life.

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8

Demetrescu, Ioana, D. Iordachescu, D. Ionita y Stef Manea. "Surface Analysis and Cell Biology Technique in Understanding Degradation of Natural Temporary Teeth Collected from an Area with High Pollution". Key Engineering Materials 396-398 (octubre de 2008): 35–38. http://dx.doi.org/10.4028/www.scientific.net/kem.396-398.35.

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The aim of this paper is to correlate surface features of degraded temporary teeth from area with high pollution with the cell adhesion and proliferation. Viability of gingival fibroblast (HGF-1, CRL-2014, American Type Culture Collection) was evaluated with a MTT (3-(4,5-dimetiltiazol-2-il)-2,5-difeniltetrazolium bromide ) test and the values are discussed for the most degraded temporary teeth in correlation with the change in surface morphology and hydrophilic/hydrophobic balance, taking into account that cell adhesion is related to a more hydrophilic character.

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9

MAlvezzi, M., B. Allotta y L. Pugi. "Feasibility of degraded adhesion tests in a locomotive roller rig". Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit 222, n.º 1 (enero de 2008): 27–43. http://dx.doi.org/10.1243/09544097jrrt108.

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10

Huang, Xuhui, Ciaron Hamilton, Zonglin Li, Lalita Udpa, Satish S. Udpa y Yiming Deng. "Capacitive imaging for adhesive bonds and quality evaluation". Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 378, n.º 2182 (14 de septiembre de 2020): 20190590. http://dx.doi.org/10.1098/rsta.2019.0590.

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Defective adhesive bonds pose significant threats towards structural integrity due to reduced joint strength. The nature of the adhesion of two solids remains poorly understood since the adhesion phenomenon is relevant to so many scientific and technological areas. A concept that has been gaining our attention from the perspective of non-destructive testing is the properties discontinuity of the adhesion. Discontinued properties depend significantly on the quality of the interface that is formed between adhesive and substrate. In this research, discontinued electrical properties at the interface are considered. The simplified model is free from multidisciplinary knowledge of chemistry, fracture mechanics, mechanics of materials, rheology and other subjects. From a practical standpoint, this emphasizes the need to establish a good relationship between electrical properties of adhesive bonds and corresponding measurements. Capacitive imaging (CI) is a technique where the dielectric property of an object is determined from external capacitance measurements. Thus, it is potentially promising since adhesive and substrate differ in terms of dielectric property. At the interface between adhesive and substrate, discontinuity of the dielectric properties causes abrupt changes in electric field spatial distribution and thus alters capacitance measurement by simulating defects in adhesive joints regarding permittivity uncertainties. Further understanding of the cause of degraded adhesion quality can be obtained. This article is part of the theme issue ‘Advanced electromagnetic non-destructive evaluation and smart monitoring’.

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11

Furuta, Nobumichi, Hiroki Takeuchi y Atsuo Amano. "Entry of Porphyromonas gingivalis Outer Membrane Vesicles into Epithelial Cells Causes Cellular Functional Impairment". Infection and Immunity 77, n.º 11 (8 de septiembre de 2009): 4761–70. http://dx.doi.org/10.1128/iai.00841-09.

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ABSTRACT Porphyromonas gingivalis, a periodontal pathogen, secretes outer membrane vesicles (MVs) that contain major virulence factors, including proteases termed gingipains (Arg-gingipain [Rgp] and Lys-gingipain [Kgp]). We recently showed that P. gingivalis MVs swiftly enter host epithelial cells via an endocytosis pathway and are finally sorted to lytic compartments. However, it remains unknown whether MV entry impairs cellular function. Herein, we analyzed cellular functional impairment following entry of P. gingivalis into epithelial cells, including HeLa and immortalized human gingival epithelial (IHGE) cells. After being taken up by endocytic vacuoles, MVs degraded the cellular transferrin receptor (TfR) and integrin-related signaling molecules, such as paxillin and focal adhesion kinase (FAK), which resulted in depletion of intracellular transferrin and inhibition of cellular migration. Few Rgp-null MVs entered the cells, and these negligibly degraded TfR, whereas paxillin and FAK degradation was significant. In contrast, Kgp-null MVs clearly entered the cells and degraded TfR, while they scarcely degraded paxillin and FAK. In addition, both wild-type and Kgp-null MVs significantly impaired cellular migration, whereas the effect of Rgp-null MVs was limited. Our findings suggest that, following entry of P. gingivalis MVs into host cells, MV-associated gingipains degrade cellular functional molecules such as TfR and paxillin/FAK, resulting in cellular impairment, indicating that P. gingivalis MVs are potent vehicles for transmission of virulence factors into host cells and are involved in the etiology of periodontitis.

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12

Meli, E., A. Ridolfi y A. Rindi. "An innovative degraded adhesion model for railway vehicles: development and experimental validation". Meccanica 49, n.º 4 (5 de diciembre de 2013): 919–37. http://dx.doi.org/10.1007/s11012-013-9839-z.

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13

Meli, E., L. Pugi y A. Ridolfi. "An innovative degraded adhesion model for multibody applications in the railway field". Multibody System Dynamics 32, n.º 2 (11 de octubre de 2013): 133–57. http://dx.doi.org/10.1007/s11044-013-9400-9.

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14

Asakura, S., R. W. Hurley, K. Skorstengaard, I. Ohkubo y D. F. Mosher. "Inhibition of cell adhesion by high molecular weight kininogen." Journal of Cell Biology 116, n.º 2 (15 de enero de 1992): 465–76. http://dx.doi.org/10.1083/jcb.116.2.465.

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An anti-cell adhesion globulin was purified from human plasma by heparin-affinity chromatography. The purified globulin inhibited spreading of osteosarcoma and melanoma cells on vitronectin, and of endothelial cells, platelets, and mononuclear blood cells on vitronectin or fibrinogen. It did not inhibit cell spreading on fibronectin. The protein had the strongest antiadhesive effect when preadsorbed onto the otherwise adhesive surfaces. Amino acid sequence analysis revealed that the globulin is cleaved (kinin-free) high molecular weight kininogen (HKa). Globulin fractions from normal plasma immunodepleted of high molecular weight kininogen (HK) or from an individual deficient of HK lacked adhesive activity. Uncleaved single-chain HK preadsorbed at neutral pH, HKa preadsorbed at pH greater than 8.0, and HKa degraded further to release its histidine-rich domain had little anti-adhesive activity. These results indicate that the cationic histidine-rich domain is critical for anti-adhesive activity and is somehow mobilized upon cleavage. Vitronectin was not displaced from the surface by HKa. Thus, cleavage of HK by kallikrein results in both release of bradykinin, a potent vasoactive and growth-promoting peptide, and formation of a potent anti-adhesive protein.

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15

Joo, Sung-Min, Young-Gon Kim, Young-Jin Kwak, Dong Jin Yoo, Chang-U. Jeong, Jeshin Park y Min-Suk Oh. "Enhanced Long-Term Reliability of Seal DeltaSpot Welded Dissimilar Joint between 6061 Aluminum Alloy and Galvannealed Steel via Excimer Laser Irradiation". Materials 14, n.º 22 (9 de noviembre de 2021): 6756. http://dx.doi.org/10.3390/ma14226756.

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Structural-adhesive-assisted DeltaSpot welding was used to improve the weldability and mechanical properties of dissimilar joints between 6061 aluminum alloy and galvannealed HSLA steel. Evaluation of the spot-weld-bonded surfaces from lap shear tests after long-term exposure to chloride and a humid atmosphere (5% NaCl, 35 °C) indicated that the long-term mechanical reliability of the dissimilar weld in a corrosive environment depends strongly on the adhesive–Al6061 alloy bond strength. Corrosive electrolyte infiltrated the epoxy-based adhesive/Al alloy interface, disrupting the chemical interactions and decreasing the adhesion via anodic undercutting of the Al alloy. Due to localized electrochemical galvanic reactions, the surrounding nugget matrix suffered accelerated anodic dissolution, resulting in an Al6061-T6 alloy plate with degraded adhesive strength and mechanical properties. KrF excimer laser irradiation of the Al alloy before adhesive bonding removed the weakly bonded native oxidic overlayers and altered the substrate topography. This afforded a low electrolyte permeability and prevented adhesive delamination, thereby enhancing the long-term stability of the chemical interactions between the adhesive and Al alloy substrate. The results demonstrate the application of excimer laser irradiation as a simple and environmentally friendly processing technology for robust adhesion and reliable bonding between 6061 aluminum alloy and galvannealed steel.

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16

Bosso, N., A. Gugliotta y N. Zampieri. "Strategies to simulate wheel–rail adhesion in degraded conditions using a roller-rig". Vehicle System Dynamics 53, n.º 5 (2 de diciembre de 2014): 619–34. http://dx.doi.org/10.1080/00423114.2014.981194.

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17

Meli, E. y A. Ridolfi. "An innovative wheel–rail contact model for railway vehicles under degraded adhesion conditions". Multibody System Dynamics 33, n.º 3 (7 de diciembre de 2013): 285–313. http://dx.doi.org/10.1007/s11044-013-9405-4.

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18

Shi, Xiangning, Qiuyan Cui, Yudong Zheng, Shuai Peng, Guojie Wang y Yajie Xie. "Effect of selective oxidation of bacterial cellulose on degradability in phosphate buffer solution and their affinity for epidermal cell attachment". RSC Adv. 4, n.º 105 (2014): 60749–56. http://dx.doi.org/10.1039/c4ra10226f.

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Oxidized bacterial cellulose showed the 3D nano-fibrils structure of BC. The mass loss and degradation rate of OBC were much higher than those of BC. When immersed in PBS, OBC degraded gradually. Cell-adhesion and proliferation studies revealed that OBC had excellent cellular affinity.

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19

Morita, Shinichiro, Toshitaka Takagi, Rie Abe, Hiroyuki Tsujimoto, Yuki Ozamoto, Hiroko Torii y Akeo Hagiwara. "Newly Developed Polyglycolic Acid Reinforcement Unified with Sodium Alginate to Prevent Adhesion". BioMed Research International 2018 (2018): 1–8. http://dx.doi.org/10.1155/2018/4515949.

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Polyglycolic acid (PGA) mesh fabric is widely used for reinforcing injured tissues during surgeries. However, PGA induces chronic inflammation and adhesion. The purpose of this study is to develop PGA reinforcement “without PGA-induced adhesion.” We developed a reinforcement fabric unified with PGA mesh and alginate foam. The antiadhesive effects of sodium alginate foam and calcium alginate foam were evaluated in rats. Sodium alginate foam unified with PGA mesh fabric exhibited strong effects that limit the extent and severity of adhesion, whereas calcium alginate foam unified with PGA mesh was less effective in preventing adhesion. In the sodium alginate group, fibroblasts and collagen fibers around implanted sites were sparse and the material degraded rapidly by macrophage ingestion. Fibroblasts and collagen fibers play a major role in adhesion formation and their excessive proliferation results in postoperative adhesion. Thus, inhibiting their increase is the key in preventing PGA-induced adhesion. The reinforcement that is composed of PGA mesh unified with sodium alginate foam strongly inhibited PGA-induced adhesion and showed excellent handling during surgery and could be easily applied with a one-step procedure.

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20

Omiya, Masaki, Hirotsugu Inoue, Kikuo Kishimoto, Masaaki Yanaka y Noritaka Ihashi. "UV-Irradiation Effects on Interfacial Strength between Thin Ceramic Film and Polymer Substrate". Key Engineering Materials 297-300 (noviembre de 2005): 2284–89. http://dx.doi.org/10.4028/www.scientific.net/kem.297-300.2284.

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This aim of this study is to investigate the effect of UV (Ultra Violet ray) irradiation on the interfacial adhesion strength between thin ceramic films and polymer substrate. Electric conductive films based on polymer substrates have attracted attention for use in flexible optoelectronic devices. It is well known that the mechanical properties of polymeric materials are degraded by UV irradiation. Therefore, it is considered that the UV irradiation also affects the interfacial adhesion strength between ceramic coating and polymer substrate. The interfacial adhesion strength was measured by Multi-stages peel test. The results show that the interfacial strength decreases with UV irradiation. However, if a filter layer is installed between ceramic and polymer substrate, the degradation ratio becomes small.

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Barski, Dimitri, Holger Gerullis, Thorsten Ecke, Gabriella Varga, Mihaly Boros, Isabel Pintelon, Jean-Pierre Timmermans y Thomas Otto. "Human Amniotic Membrane Is Not Suitable for the Grafting of Colon Lesions and Prevention of Adhesions in a Xenograft Rat Model". Surgical Innovation 24, n.º 4 (26 de mayo de 2017): 313–20. http://dx.doi.org/10.1177/1553350617709828.

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Introduction. New biological materials are needed for specific applications in reconstructive bowel surgery and for the prevention of adhesion formation. Amniotic membranes (AMs) are assumed to have a number of unique characteristics that enhance the ingrowth of the surrounding tissue. The aim of the present study was to provide proof of these qualities in a xenograft model. Materials and methods. A multilayer human AM (HAM) was applied to repair defined colon wall defects in Sprague-Dawley rats (n = 18). The control group was repaired with a suture (n = 6). The animals were killed humanely at 7, 21, and 42 days after implantation. Adhesions and perioperative complications were examined. Histological and immunohistological analyses were performed to assess a number of parameters, including degradation of the HAM, inflammation, graft rejection, and smooth muscle ingrowth. Results. Two rats in the treated group died. No other severe complications were observed. Adhesion formation was more prominently visible in the HAM group ( P < .05). The initially increased inflammation in the HAM group reduced over time but remained significantly increased ( P < .05). The HAM degraded over time and a subtle transient glomerulitis could be observed. Conclusion. HAMs were found to increase adhesion formation and were not suitable for bowel augmentation in the presented xenograft model.

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Zhang, Hui, Xin-Yuan Sun, Xue-Wu Chen y Jian-Ming Ouyang. "Degraded Porphyra yezoensis polysaccharide protects HK-2 cells and reduces nano-COM crystal toxicity, adhesion and endocytosis". Journal of Materials Chemistry B 8, n.º 32 (2020): 7233–52. http://dx.doi.org/10.1039/d0tb00360c.

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23

Pugi, Luca, Francesco Grasso, Marco Pratesi, Marco Cipriani y Argeo Bartolomei. "Design and preliminary performance evaluation of a four wheeled vehicle with degraded adhesion conditions". International Journal of Electric and Hybrid Vehicles 9, n.º 1 (2017): 1. http://dx.doi.org/10.1504/ijehv.2017.082812.

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Bartolomei, Argeo, Marco Cipriani, Marco Pratesi, Francesco Grasso y Luca Pugi. "Design and preliminary performance evaluation of a four wheeled vehicle with degraded adhesion conditions". International Journal of Electric and Hybrid Vehicles 9, n.º 1 (2017): 1. http://dx.doi.org/10.1504/ijehv.2017.10003707.

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25

Zhang, J., C. Q. Cui, T. B. Lim y E. T. Kang. "Surface Graft Copolymerization Enhanced Lamination of Poly(tetrafluoroethylene) Film to Copper and Epoxy-Based Print Circuit Board (PCB)". Journal of Electronic Packaging 121, n.º 4 (1 de diciembre de 1999): 291–96. http://dx.doi.org/10.1115/1.2793855.

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Lamination of poly(tetrafluoroethylene) (PTFE) film to a copper foil or to an epoxy-based print circuit board (PCB) Substrate (FR4®) was carried out. Lamination was achieved during surface graft copolymerization of glycidyl methacrylate (GMA) on an Ar plasma pretreated PTFE film at elevated temperature and in the presence of an epoxy resin adhesive. The plasma pretreatment introduces peroxides which are thermally degraded into free radicals to initiate the graft polymerization of GMA on the PTFE surface. The graft copolymerization with concurrent lamination is carried out in the complete absence of a polymerization initiator or system degassing. The modified surfaces and interfaces are characterized by X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM). The adhesion strength between the PTFE film and copper or the FR4® substrate was assessed by the T-peel strength test method. The adhesion strength was affected by plasma pretreatment time, as well as the grafting and curing temperature. The PTFE/GMA-epoxy resin/Cu and PTFE/GMA-epoxy resin/FR4 assemblies exhibit significant higher interfacial adhesion strengths compared to those assemblies in which only epoxy resin or GMA was used. They also exhibit better interfacial adhesion reliability. The PTFE/GMA-epoxy resin/Cu and PTFE/GMA-epoxy resin/FR4® joints delaminated by cohesive failure inside the bulk of PTFE film. The results suggest that the enhanced adhesion between the graft-modified PTFE film and copper or FR4® surfaces is attributable to the formation of covalent bonds between the tethered GMA graft chains on PTFE and the network of epoxy resin.

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Wang, Xuan, Hao Ding, Sijia Sun, Han Zhang, Run Zhou, Yangzi Li, Jie Wang y Weihua Ao. "Tunable Adhesive Self-Cleaning Coating with Superhydrophobicity and Photocatalytic Activity". Nanomaterials 11, n.º 6 (3 de junio de 2021): 1486. http://dx.doi.org/10.3390/nano11061486.

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Superhydrophobic coatings with intelligent properties have attracted much attention because of their wide application in many fields. However, there is a limited amount of literature on superhydrophobic coatings whose wettability and adhesion can be adjusted by UV irradiation and calcination at the same time. In this study, amorphous SiO2 microspheres (A-SiO2) and nano-TiO2 particles (N-TiO2) were used to fabricate A-SiO2/N-TiO2 composites by wet grinding, and then, they were modified with polydimethylsiloxane (PDMS) and sprayed onto substrate surfaces to obtain a tunable adhesive superhydrophobic A-SiO2/N-TiO2@PDMS coating. It is worth noting that the wettability and adhesion of the coating to water droplets could be adjusted by UV irradiation and calcination. The mechanisms of the aforementioned phenomena were studied. Moreover, methyl orange solution could be degraded by the coating due to its photocatalysis. The as-prepared coating had good adaptation to different substrates and outdoor environments. Moreover, the surfaces of these coatings exhibited the same liquid repellency towards different droplets. This research provides an environmental strategy to prepare advanced self-cleaning coatings.

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27

Hintermann, Edith, Susan Kinder Haake, Urs Christen, Andrew Sharabi y Vito Quaranta. "Discrete Proteolysis of Focal Contact and Adherens Junction Components in Porphyromonas gingivalis-Infected Oral Keratinocytes: a Strategy for Cell Adhesion and Migration Disabling". Infection and Immunity 70, n.º 10 (octubre de 2002): 5846–56. http://dx.doi.org/10.1128/iai.70.10.5846-5856.2002.

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ABSTRACT Adhesive interactions of cells are critical to tissue integrity. We show that infection with Porphyromonas gingivalis, a major pathogen in the periodontal disease periodontitis, interferes with both cell-matrix and cell-cell adhesion in the oral keratinocyte cell line HOK-16. Thus, infected cells showed reduced adhesion to extracellular matrix, changes in morphology from spread to rounded, and impaired motility on purified matrices in Transwell migration assays and scratch assays. Western blot analysis of P. gingivalis-challenged HOK-16 cells revealed proteolysis of focal contact components (e.g., focal adhesion kinase), adherens junction proteins (e.g., catenins), and adhesion signaling molecules (e.g., the tyrosine kinase SRC). Proteolysis was selective, since important components of adherens junctions (E-cadherin) or signaling molecules (extracellular signal-regulated kinases ERK1/2) were not degraded. The virulence factors gingipains, cysteine proteinases expressed by P. gingivalis, are likely responsible for this proteolytic attack, since they directly digested specific proteins in pull-down experiments, and their proteolytic activity was blocked by the cysteine proteinase inhibitor N-α-p-tosyl-l-lysine chloromethyl ketone and also by a caspase inhibitor. Proteolysis was strain dependent, such that ATCC 33277 and 381 had high proteolytic potential, whereas W50 showed almost no proteolytic activity. These findings may help explain the formation of gingival pockets between cementum and periodontal epithelium, a hallmark of periodontitis. Furthermore, they illustrate a new pathogenetic paradigm of infection whereby bacteria may disrupt the integrity of epithelia.

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Sarlin, Essi, Ari Rosling, Mari Honkanen, Mari Lindgren, Mira Juutilainen, Minna Poikelispää, Paavo Laihonen, Minnamari Vippola y Jyrki Vuorinen. "EFFECT OF ENVIRONMENT ON BROMOBUTYL RUBBER–STEEL ADHESION". Rubber Chemistry and Technology 93, n.º 2 (4 de octubre de 2019): 429–44. http://dx.doi.org/10.5254/rct.19.80455.

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ABSTRACT Optimizing the maintenance cycles of rubber-lined components is of great importance. Especially for the industry sectors operating under demanding conditions, challenges in the lifetime evaluation of rubber linings may cause apparent premature failures. Thus, understanding the effect of environmental factors on the performance and durability of rubber linings, as well as on the weakest links of the structure in certain environments, is essential. The performances of bromobutyl rubber and rubber–steel interfaces after exposure to different environments, namely, high temperature (95 °C), moisture (95% relative humidity and immersion), and sulfuric acid (solution with 75 g/L of acid) were investigated. The weakest link of the rubber–metal structure and, consequently, the location of the fracture were mostly within the adhesive layer or at the primer–metal interface. However, the most degraded component of the adhesive system depends on the aging environments.

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Streger, Sheryl H., Simon Vainberg, Hailiang Dong y Paul B. Hatzinger. "Enhancing Transport of Hydrogenophagaflava ENV735 for Bioaugmentation of Aquifers Contaminated with Methyl tert-Butyl Ether". Applied and Environmental Microbiology 68, n.º 11 (noviembre de 2002): 5571–79. http://dx.doi.org/10.1128/aem.68.11.5571-5579.2002.

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ABSTRACT The gasoline oxygenate methyl tert-butyl ether (MTBE) has become a widespread contaminant in groundwater throughout the United States. Bioaugmentation of aquifers with MTBE-degrading cultures may be necessary to enhance degradation of the oxygenate in some locations. However, poor cell transport has sometimes limited bioaugmentation efforts in the past. The objective of this study was to evaluate the transport characteristics of Hydrogenophaga flava ENV735, a pure culture capable of growth on MTBE, and to improve movement of the strain through aquifer solids. The wild-type culture moved only a few centimeters in columns of aquifer sediment. An adhesion-deficient variant (H. flava ENV735:24) of the wild-type strain that moved more readily through sediments was obtained by sequential passage of cells through columns of sterile sediment. Hydrophobic and electrostatic interaction chromatography revealed that the wild-type strain is much more hydrophobic than the adhesion-deficient variant. Electrophoretic mobility assays and transmission electron microscopy showed that the wild-type bacterium contains two distinct subpopulations, whereas the adhesion-deficient strain has only a single, homogeneous population. Both the wild-type strain and adhesion-deficient variant degraded MTBE, and both were identified by 16S rRNA analysis as pure cultures of H. flava. The effectiveness of surfactants for enhancing transport of the wild-type strain was also evaluated. Many of the surfactants tested were toxic to ENV735; however, one nonionic surfactant, Tween 20, enhanced cell transport in sand columns. Improving microbial transport may lead to a more effective bioaugmentation strategy for MTBE-contaminated sites where indigenous oxygenate degraders are absent.

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Chaires-Rosas, Casandra P., Xóchitl Ambriz, Juan J. Montesinos, Beatriz Hernández-Téllez, Gabriela Piñón-Zárate, Miguel Herrera-Enríquez, Érika Hernández-Estévez, Javier R. Ambrosio y Andrés Castell-Rodríguez. "Differential adhesion and fibrinolytic activity of mesenchymal stem cells from human bone marrow, placenta, and Wharton’s jelly cultured in a fibrin hydrogel". Journal of Tissue Engineering 10 (enero de 2019): 204173141984062. http://dx.doi.org/10.1177/2041731419840622.

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Mesenchymal stem cells isolated from different tissues should share associated markers and the capability to differentiate to mesodermal lineages. However, their behavior varies in specific microenvironments. Herein, adhesion and fibrinolytic activity of mesenchymal stem cells from placenta, bone marrow, and Wharton’s jelly were evaluated in fibrin hydrogels prepared with nonpurified blood plasma and compared with two-dimensional cultures. Despite the source, mesenchymal stem cells adhered through focal adhesions positive for vinculin and integrin αV in two dimensions, while focal adhesions could not be detected in fibrin hydrogels. Moreover, some cells could not spread and stay rounded. The proportions of elongated and round phenotypes varied, with placenta mesenchymal stem cells having the lowest percentage of elongated cells (~10%). Mesenchymal stem cells degraded fibrin at distinct rates, and placenta mesenchymal stem cells had the strongest fibrinolytic activity, which was achieved principally through the plasminogen–plasmin axis. These findings might have clinical implications in tissue engineering and wound healing therapy.

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Crescenzi, Francesco, Marcello Camilli, Eugenio Fascetti, Filippo Porcelli, Giulio Prosperi y Pasquale Sacceddu. "Microbial Degradation of Biosurfactant Dispersed Oil". International Oil Spill Conference Proceedings 1999, n.º 1 (1 de marzo de 1999): 1039–42. http://dx.doi.org/10.7901/2169-3358-1999-1-1039.

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ABSTRACT Biological degradation of a light crude dispersed in sea water by a surfactant produced by an hydrocarbon degrading microorganism has been monitored in laboratory tests. Oligotrophic natural sea water was used with no additions. Results showed that the oil dispersed by the biosurfactant was more easily degraded than chemically dispersed oil. In adhesion tests it has been found that the number of microbial cells adhering to a water/hexadecane interface increases in presence of the biosurfactant. It is suggested that the biodegradation enhancement may be linked to a promoting action carried by the biosurfactant on the adhesion of degrading microorganisms onto the surface of the oil.

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Culty, M., H. A. Nguyen y C. B. Underhill. "The hyaluronan receptor (CD44) participates in the uptake and degradation of hyaluronan." Journal of Cell Biology 116, n.º 4 (15 de febrero de 1992): 1055–62. http://dx.doi.org/10.1083/jcb.116.4.1055.

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The hyaluronan receptor belongs to the polymorphic family of CD44 glycoproteins, which have been implicated in a variety of cellular functions including adhesion to hyaluronan and collagen, the binding of lymphocytes to high endothelial cells during extravasation, and conferring metastatic potential to carcinoma cells. Here, we demonstrate that the receptor also participates in the uptake and degradation of hyaluronan by both transformed fibroblasts (SV-3T3 cells) and alveolar macrophages. These cells were incubated with isotopically labeled hyaluronan for various periods of time, and the extent of degradation was determined by either molecular-sieve chromatography or centrifugation through Centricon 30 microconcentrators. The macrophages degraded the hyaluronan at a faster rate than the SV-3T3 cells, which may reflect the fact that they contained a greater number of receptors. More importantly, in both cell types, the degradation of hyaluronan was specifically blocked by antibodies directed against the receptor. However, the receptor by itself did not have the ability to degrade hyaluronan, since preparations of SV-3T3 membranes containing the receptor did not break down hyaluronan. Subsequent experiments revealed that macrophages can internalize fluorescein-tagged hyaluronan, and this process was blocked by antibodies against the receptor. Furthermore, the subsequent degradation of hyaluronan was inhibited by agents that block the acidification of lysosomes (chloroquine and NH4Cl). Thus, the most likely explanation for these results is that the receptor mediates the uptake of hyaluronan into the cell where it can be degraded by acid hydrolases in lysosomes. The ability of cells expressing the receptor to degrade hyaluronan may be important during tissue morphogenesis and cell migration.

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Winters, KJ, PR Eisenberg, AS Jaffe y SA Santoro. "Dependence of plasmin-mediated degradation of platelet adhesive receptors on temperature and Ca2+". Blood 76, n.º 8 (15 de octubre de 1990): 1546–57. http://dx.doi.org/10.1182/blood.v76.8.1546.1546.

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Abstract The effects of activation of plasminogen by streptokinase and tissue- type-plasminogen activator on platelet activation and the membrane glycoproteins (GPs) that mediate platelet adhesion and aggregation are not yet fully defined. To clarify effects on platelets during activation of plasminogen in vitro, we used monoclonal antibodies (MoAbs), flow cytometry, and platelets surface-labeled with 125I to characterize changes in receptors for fibrinogen (GPIIb-IIIa), von Willebrand factor (GPIb), and collagen (GPIa-IIa). Activation of plasminogen in plasma with pharmacologic concentrations of plasminogen activators did not degrade GPIIb-IIIa or GPIb, and caused only a modest decrease in GPIa. In washed platelets GPIIb-IIIa was extensively degraded by plasmin at 37 degrees C in the absence of exogenous Ca2+, conditions that destabilize the IIb-IIIa complex. Degradation of GPIb in washed platelets displayed a similar although less-marked dependence on temperature and the absence of Ca2+. The binding of activation- specific MoAbs did not increase during activation of plasminogen in plasma. We conclude that during pharmacologic fibrinolysis, reported inhibition of platelet function in plasma is not due to degradation of platelet-adhesive receptors. In addition, platelet activation observed during thrombolytic therapy does not appear to be a direct consequence of plasminogen activation.

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34

Winters, KJ, PR Eisenberg, AS Jaffe y SA Santoro. "Dependence of plasmin-mediated degradation of platelet adhesive receptors on temperature and Ca2+". Blood 76, n.º 8 (15 de octubre de 1990): 1546–57. http://dx.doi.org/10.1182/blood.v76.8.1546.bloodjournal7681546.

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The effects of activation of plasminogen by streptokinase and tissue- type-plasminogen activator on platelet activation and the membrane glycoproteins (GPs) that mediate platelet adhesion and aggregation are not yet fully defined. To clarify effects on platelets during activation of plasminogen in vitro, we used monoclonal antibodies (MoAbs), flow cytometry, and platelets surface-labeled with 125I to characterize changes in receptors for fibrinogen (GPIIb-IIIa), von Willebrand factor (GPIb), and collagen (GPIa-IIa). Activation of plasminogen in plasma with pharmacologic concentrations of plasminogen activators did not degrade GPIIb-IIIa or GPIb, and caused only a modest decrease in GPIa. In washed platelets GPIIb-IIIa was extensively degraded by plasmin at 37 degrees C in the absence of exogenous Ca2+, conditions that destabilize the IIb-IIIa complex. Degradation of GPIb in washed platelets displayed a similar although less-marked dependence on temperature and the absence of Ca2+. The binding of activation- specific MoAbs did not increase during activation of plasminogen in plasma. We conclude that during pharmacologic fibrinolysis, reported inhibition of platelet function in plasma is not due to degradation of platelet-adhesive receptors. In addition, platelet activation observed during thrombolytic therapy does not appear to be a direct consequence of plasminogen activation.

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35

Cheng, Jie, Nanxuan Mei, Sulin Chen, Pengpeng Bai, Bin Shen, Jinshan Pan y Fan Zhang. "Interactions in Composite Film Formation of Mefp-1/graphene on Carbon Steel". Coatings 11, n.º 10 (27 de septiembre de 2021): 1161. http://dx.doi.org/10.3390/coatings11101161.

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Mefp-1 adhesive protein derived from marine blue mussels, together with the 2D material graphene, was used to build the green composite film with enhanced anti-corrosion property and mechanical strength. The corrosion inhibition of the composite film, formed by different methods, was evaluated by using electrochemical impedance spectroscopy. The non-degraded adhesion of the composite film to the carbon steel substrate was proved by nano-scratch tests. Infrared spectroscopy was utilized to investigate the film formation process and “three-body interactions” between Mefp-1, graphene and carbon steel surface. The results show that the Mefp-1 adsorbs on the carbon steel surface mainly through the covalent bond between catechols and Fe(III). Meanwhile, Mefp-1 can bond to non-adhesive graphene by forming hydrogen bonds and π−π interaction non-covalent bonds, which facilitate the formation of a robust Mefp-1/graphene composite film on the carbon steel surface.

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36

Wandscher, Vinícius Felipe, Luana Brondani, Gabriel Kalil Rocha Pereira y Renata Marques De Melo. "Effect of several repair techniques on the bond strength between composite resin and degraded Y-TZP ceramic". Brazilian Dental Science 21, n.º 4 (24 de octubre de 2018): 377. http://dx.doi.org/10.14295/bds.2018.v21i4.1596.

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Objective: To evaluate the bond strength of different repair treatments for composite resin to aged Y-TZP ceramics. Material and Methods: Zirconia blocks were cut into smaller specimens, sintered according to manufacturer’s recommendations (final dimensions of 4×4×3 mm), and randomly allocated into nine groups (n=15) according to the surface treatment and presence/absence of aging of the substrate (subjected to low-temperature degradation - LTD), as follows: without LTD (Control: without treatment; TBS: tribochemical silica coating + silane + adhesive); with LTD (Control-LTD: without treatment; TBS-LTD: TBS with hydrothermal degradation; MoS-LTD: Monobond S + adhesive; MoP-LTD: Monobond Plus + adhesive; MZP-LTD: Metal/Zirconia Primer + adhesive; USB-LTD: Single Bond Universal; AP-LTD: Alloy primer + adhesive). LTD was simulated in an autoclave (134 °C, 2 bar, 5 h). The ceramic blocks were embedded in PVC cylinders with a self-curing acrylic resin; each surface treatment protocol was performed; a composite resin cylinder (Æ: 3.25 mm and height: 3 mm) was then build-up using split metallic matrices. All the specimens were aged (thermocycling + storage in water for 90 days) and subjected to the shear bond strength test using a universal testing machine (1 mm/min). The failure mode was classified into four types: adhesive, composite resin cohesive fracture, ceramic cohesive fracture, and mixed. The bond strength values were subjected to Mann–Whitney test. Results: Only air-abraded samples (TBS and TBS–LTD) survived thermocycling. More than 80% of the samples of the other groups presented pre-test failures. TBS groups presented higher values of bond strength (3.94) compared to TBS-LTD (0.96). The predominant type of failure for the surviving samples were adhesive. Conclusion: Air particle abrasion is mandatory to improve the bond strength of the Y-TZP substrate; an aged substrate presents an even more unfavorable scenario for adhesion.Keywords Dental prosthesis repair; Hydrothermal degradation; Zirconia; Shear bond strength; Sandblasting.

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Jung, Ju-Young, Myung Hoon Kim, Hee Soo Moon y Jong Wan Park. "Electrochemical Characteristics of Si/Mo Multilayer Anode for Microbattery in MEMS". Materials Science Forum 486-487 (junio de 2005): 558–61. http://dx.doi.org/10.4028/www.scientific.net/msf.486-487.558.

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We have prepared the Si/Mo multilayer consisting of active/inactive material using rf/dc magnetron sputtering. The pre-treatment using an ECR plasma were introduced at current collector for the adhesion and removal of surface contamination. The structural and electrochemical characteristics of multilayers have been investigated. The multilayer nearly maintained more than 90 % of the initial capacity (2653 mAh/g) after 100 cycles whereas the Si thin film was gradually degraded after 40 cycles.

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38

Bhushan, Bharat, Michal Cichomski, Zhenhua Tao, Nang T. Tran, Todd Ethen, Chris Merton y Richard E. Jewett. "Nanotribological Characterization and Lubricant Degradation Studies of Metal-Film Magnetic Tapes Using Novel Lubricants". Journal of Tribology 129, n.º 3 (17 de enero de 2007): 621–27. http://dx.doi.org/10.1115/1.2736454.

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In order to improve the durability of metal-film magnetic tapes, novel lubricants, A20H, X-1P, and X, a modified phosphazene, were deposited on the tapes. The adhesion, friction, and wear of the unlubricated/lubricated tapes were investigated using an atomic force microscope (AFM). The degradation of the lubricants was studied using a mass spectrometer in high vacuum. The durability of various unlubricated/lubricated tapes was compared in ambient and in humid air. The AFM test results show that the A20H lubricated tape exhibited lower adhesion and friction than X-1P and X lubricated tapes. The lubricants were believed to be mainly degraded by tribochemical reaction and mechanical shear in high vacuum. In high humidity air, the various lubricated tapes exhibit higher friction than in ambient air. By comparing the tribological performances of the various lubricated tapes to metal particle (MP) tape, it was found that the lubricated metal-film tapes exhibit lower adhesion, friction, and wear than the MP tape.

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Kalamees, Targo, Simo Ilomets, Mattias Põldaru, Paul Klõseiko, Urve Kallavus, Margit Rosenberg y Karl Õiger. "Analysis of causes of the end of service life of a spray polyurethane foam and polyurea roof". E3S Web of Conferences 172 (2020): 15002. http://dx.doi.org/10.1051/e3sconf/202017215002.

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Spray polyurethane foam (SPF) roofs are widely used in North America. Much fewer usage examples and experience can be found in Northern European cold climatic conditions. This study analyses hygrothermal performance and the reasons for the roof’s degradation and end of service life of an SPF and polyurea roof. The service life of the roof is over and major reconstruction is needed eight year after construction. The current study uses field measurements included onsite temperature and humidity measurements and extensive surveying, the roof was opened from several locations and test samples were taken for laboratory tests. The influence of UV radiation on the loss of adhesion was tested. Solar radiation quickly degraded the top surface of the in-situ sprayed polyurethane foam insulation causing a weak connection between the foam layers. Due to mechanically damaged and UV degraded polyurea roofing, water has leaked into the SPF. The water inside or below the foam evaporated during sunny days and broke the adhesion of different foam layers. Larger foam blisters were observed on the upper part of the insulation caused by high water vapour pressure. This is considered the most realistic cause of separation of the SPF layers. The analyse of hygrothermal performance, service life, and durability prediction should be included into the design process, especially for structures with small or without long term performance experience.

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Conti, Roberto, Enrico Meli, Luca Pugi, Monica Malvezzi, Fabio Bartolini, Benedetto Allotta, Andrea Rindi y Paolo Toni. "A numerical model of a HIL scaled roller rig for simulation of wheel–rail degraded adhesion condition". Vehicle System Dynamics 50, n.º 5 (mayo de 2012): 775–804. http://dx.doi.org/10.1080/00423114.2011.640402.

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Allotta, B., E. Meli, A. Ridolfi y A. Rindi. "Development of an innovative wheel–rail contact model for the analysis of degraded adhesion in railway systems". Tribology International 69 (enero de 2014): 128–40. http://dx.doi.org/10.1016/j.triboint.2013.09.013.

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42

Meacci, Martina, Zhiyong Shi, Elisa Butini, Lorenzo Marini, Enrico Meli y Andrea Rindi. "A local degraded adhesion model for creep forces evaluation: An approximate approach to the tangential contact problem". Wear 440-441 (diciembre de 2019): 203084. http://dx.doi.org/10.1016/j.wear.2019.203084.

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43

Dalton, S. L., E. Scharf, R. Briesewitz, E. E. Marcantonio y R. K. Assoian. "Cell adhesion to extracellular matrix regulates the life cycle of integrins." Molecular Biology of the Cell 6, n.º 12 (diciembre de 1995): 1781–91. http://dx.doi.org/10.1091/mbc.6.12.1781.

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The expression of alpha 5 beta 1 integrin on the surface of fibroblasts requires adhesion to substratum. We have examined the basis for this adhesion-dependent surface expression by comparing the life cycle of integrins in parallel cultures of adherent and nonadherent cells. Results of biosynthetic labeling experiments in NRK fibroblasts showed that the synthesis and biosynthetic processing of the beta 1 integrin subunit proceed in the absence of cell attachment; however, when examining the behavior of preexisting cell surface integrins, we observed that the alpha beta 1 integrins are internalized and degraded when adhesion to substratum is blocked. A kinetic analysis of integrin internalization in cycloheximide-treated NRK cells showed that each of the fibroblast integrins we examined (in both the beta 1 and beta 3 families) are lost from the cell surface after detachment from substratum. Thus, the default integrin life cycle in fibroblasts involves continuous synthesis, processing, transport to the cell surface, and internalization/degradation. Interestingly, studies with NIH-3T3 cells expressing alpha 1 beta 1 integrin showed that the loss of cell-surface alpha 5 beta 1 integrin is blocked by adhesion of cells to dishes coated with type IV collagen (a ligand for alpha 1 beta 1 integrin) as well as fibronectin. Similarly, adhesion of these cells to dishes coated with type IV collagen stabilizes the surface expression of alpha 5 beta 1 as well as alpha 1 beta 1 integrin. We propose that the adhesion of fibroblasts to extracellular matrix protein alters the integrin life cycle and permits retention of these proteins at the cell surface where they can play important roles in transmitting adhesion-dependent signals.

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Harris, Elizabeth S. y W. James Nelson. "Adenomatous Polyposis Coli Regulates Endothelial Cell Migration Independent of Roles in β-Catenin Signaling and Cell–Cell Adhesion". Molecular Biology of the Cell 21, n.º 15 (agosto de 2010): 2611–23. http://dx.doi.org/10.1091/mbc.e10-03-0235.

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Adenomatous polyposis coli (APC), a tumor suppressor commonly mutated in cancer, is a cytoskeletal organizer for cell migration and a scaffold for GSK3β/CKI-mediated phosphorylation and degradation of the Wnt effector β-catenin. It remains unclear whether these different APC functions are coupled, or independently regulated and localized. In primary endothelial cells, we show that GSK3β/CKI-phosphorylated APC localizes to microtubule-dependent clusters at the tips of membrane extensions. Loss of GSK3β/CKI-phosphorylated APC from these clusters correlates with a decrease in cell migration. GSK3β/CKI-phosphorylated APC and β-catenin at clusters is degraded rapidly by the proteasome, but inhibition of GSK3β/CKI does not increase β-catenin–mediated transcription. GSK3β/CKI-phosphorylated and -nonphosphorylated APC also localize along adherens junctions, which requires actin and cell–cell adhesion. Significantly, inhibition of cell–cell adhesion results in loss of lateral membrane APC and a concomitant increase in GSK3β/CKI-phosphorylated APC in clusters. These results uncouple different APC functions and show that GSK3β/CKI phosphorylation regulates APC clusters and cell migration independently of cell–cell adhesion and β-catenin transcriptional activity.

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45

Hershkoviz, R., L. Preciado-Patt, O. Lider, M. Fridkin, J. Dastych, D. D. Metcalfe y Y. A. Mekori. "Extracellular matrix-anchored serum amyloid A preferentially induces mast cell adhesion". American Journal of Physiology-Cell Physiology 273, n.º 1 (1 de julio de 1997): C179—C187. http://dx.doi.org/10.1152/ajpcell.1997.273.1.c179.

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Mast cells are known to accumulate in various inflammatory processes, some of which are known to be associated with increased local and systemic levels of acute-phase reactants such as serum amyloid A (SAA) or with amyloid deposition. The mechanism(s) by which mast cells are recruited to these sites, however, has not been fully elucidated. It has recently been shown that SAA interacts with extracellular matrix (ECM) components and thereby acts as a chemoattractant and regulator of immune cell migration. On the basis of these observations, we examined the effect of SAA on mast cell adhesion to ECM, an essential step in cellular transmigration. We could first demonstrate strong specific binding of recombinant human SAA (rSAA) to murine mast cells using flow cytometry. Moreover, radiolabeled rSAA was found to bind, in a saturable manner, to mast cells, reaching a binding affinity of 10(-8) M. When immobilized by preincubation with ECM, SAA or its proteolytically degraded amyloid A fragment (amino acid residues 2-82), which contains RGD-related adhesion motif but not the COOH-terminal portion of SAA (amino acid residues 77-104), induced the adhesion of resting mast cells to ECM or laminin. SAA and AA, in soluble or immobilized forms, did not activate mast cells to release mediators. Mast cell adhesion to the immobilized ECM-SAA complex appeared to occur through an integrin recognition, inasmuch as adhesion was calcium dependent and could be blocked by an RGD-containing peptide or by anti-CD29 monoclonal antibody. Genistein also inhibited adhesion, indicating that tyrosine kinase activity was involved. These data suggest that SAA bound to ECM may serve as an important inducer of mast cell adhesion, thus regulating mast cell recruitment and accumulation at these sites, which in turn could potentiate further pathology.

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Xiong, Gang, Zhanping Zhang, Chen Zhang y Yuhong Qi. "SLAP@g-C3N4 Fluorescent Photocatalytic Composite Powders Enhance the Anti-Bacteria Adhesion Performance and Mechanism of Polydimethylsiloxane Coatings". Nanomaterials 12, n.º 17 (30 de agosto de 2022): 3005. http://dx.doi.org/10.3390/nano12173005.

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Fluorescent antifouling and photocatalytic antifouling technologies have shown potential in the field of marine antifouling. SLAP@g-C3N4/PDMS (SLAP@CN/PDMS) composite antifouling coatings were designed and prepared using g-C3N4, sky-blue long afterglow phosphor (SLAP), and polydimethylsiloxane (PDMS). The fluorescence emitted by SLAP under dark conditions was used to excite g-C3N4 for fluorescent photocatalysis and to prolong the photocatalytic activity of g-C3N4. Key data were collected by testing and characterization and are presented in this work. The results showed that g-C3N4 was successfully coated on the SLAP surface and formed a heterogeneous structure. After the composite powder was added to the PDMS coating, the coating maintained low surface energy but enhanced the surface roughness of the coating. The experimental results of degraded Rhodamine B (RhB) showed that SLAP prolonged the g-C3N4 photocatalytic activity time. The anti-marine bacterial adhesion performance of the coating was investigated by bacterial adhesion experiments. The results showed that SLAP@CN could effectively improve the anti-bacterial adhesion performance of PDMS coating, in which the anti-bacterial adhesion performance of SLAP@CN-2.5/PDMS was improved by nearly 19 times. This antifouling coating introduces fluorescent antifouling, photocatalytic antifouling, and fluorescence-driven photocatalytic antifouling based on the low surface energy antifouling of silicones and achieves “all-weather” fluorescent photocatalytic antifouling.

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47

Lillehoj, E. P., S. W. Hyun, B. T. Kim, X. G. Zhang, D. I. Lee, S. Rowland y K. C. Kim. "Muc1 mucins on the cell surface are adhesion sites forPseudomonas aeruginosa". American Journal of Physiology-Lung Cellular and Molecular Physiology 280, n.º 1 (1 de enero de 2001): L181—L187. http://dx.doi.org/10.1152/ajplung.2001.280.1.l181.

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Recently, we cloned and characterized a full-length cDNA of the hamster Muc1 gene, the expression of which appears to be associated with secretory cell differentiation (Park HR, Hyun SW, and Kim KC. Am J Respir Cell Mol Biol 15: 237–244, 1996). The role of Muc1 mucins in the airway, however, is unknown. In this study, we investigated whether cell surface mucins are adhesion sites for Pseudomonas aeruginosa. Chinese hamster ovary (CHO) cells not normally expressing Muc1 mucin were stably transfected with the hamster Muc1 cDNA, and binding to P. aeruginosa was examined. Our results showed that 1) stably transfected CHO cells expressed both Muc1 mRNA and Muc1 mucins based on Northern and Western blot analyses, 2) Muc1 mucins present on the cell surface were degraded by neutrophil elastase, and 3) expression of Muc1 mucins on the cell surface resulted in a significant increase in adhesion of P. aeruginosa that was completely abolished by either proteolytic cleavage with neutrophil elastase or deletion of the extracellular domain by mutation. We conclude that Muc1 mucins expressed on the surface of CHO cells serve as adhesion sites for P. aeruginosa, suggesting a possible role for these glycoproteins in the early stage of airway infection and providing a model system for studying epithelial cell responses to bacterial adhesion that leads to airway inflammation in general and cystic fibrosis in particular.

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48

Wang, Yang-Kao, Hsi-Hui Lin y Ming-Jer Tang. "Collagen gel overlay induces two phases of apoptosis in MDCK cells". American Journal of Physiology-Cell Physiology 280, n.º 6 (1 de junio de 2001): C1440—C1448. http://dx.doi.org/10.1152/ajpcell.2001.280.6.c1440.

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We previously demonstrated that collagen gel overlay induced cell remodeling to form lumen and apoptosis in Madin-Darby canine kidney cells. In the present study, we established that collagen gel overlay-induced apoptosis was initiated at areas exclusive of cell remodeling within 24 h (first phase) and extended into areas of cell remodeling within 48 h (second phase). Collagen gel overlay-induced apoptosis was accompanied by selective proteolysis of focal adhesion kinase (FAK), talin, p130cas, and c- src. Upon collagen gel overlay, FAK was initially degraded into a 90-kDa product during the first phase and subsequently into a 80-kDa product during the second phase. Collagen gel overlay-induced apoptosis of focal adhesion complex proteins and apoptosis of the first phase could be blocked only by a protease inhibitor cocktail. In addition, we found that both DEVD-fmk and ZVAD-fmk inhibited secondary proteolysis of FAK, but only ZVAD-fmk blocked collagen gel overlay-induced apoptosis of the second phase. Finally, collagen gel overlay-induced apoptosis and proteolysis of focal adhesion complex proteins were completely inhibited by the combination of protease inhibitor cocktail and ZVAD-fmk. Taken together, collagen gel overlay induces two phases of apoptosis; the first phase is dependent on proteolysis of focal adhesion complex proteins, and the second phase on activation of caspases.

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49

Bobo, S. N. "Fatigue Life of Aircraft Tires". Tire Science and Technology 16, n.º 4 (1 de octubre de 1988): 208–22. http://dx.doi.org/10.2346/1.2148807.

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Abstract A study was conducted to determine if a safe upper service limit can be set for aircraft tires, based on an operation profile of the aircraft using the tires. The study consisted of three parts: development of a tire heating model, experimental confirmation, and determination of tire degradation as a function of time at temperature. Three operational profiles were identified: long, intermediate, and short haul; these stressed tires in different ways. The mathematical model, which calculated temperature as a function of time for various axial and lateral forces at different speeds, was developed and confirmed by experiment. It predicted the time at temperature of the hottest part of a tire that is exposed to the operating environment of the profiles. The impact of heating was found from a determination of ply adhesion as a function of time at temperature. The end of tire life was judged to occur when ply adhesion was degraded by 50%.

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Tada, H., S. Sugawara, E. Nemoto, T. Imamura, J. Potempa, J. Travis, H. Shimauchi y H. Takada. "Proteolysis of ICAM-1 on Human Oral Epithelial Cells by Gingipains". Journal of Dental Research 82, n.º 10 (octubre de 2003): 796–801. http://dx.doi.org/10.1177/154405910308201007.

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Cysteine proteinases (gingipains) from Porphyromonas gingivalis are considered key virulence factors of severe periodontitis and host immune evasion. Since expression of intercellular adhesion molecule-1 (ICAM-1) on gingival epithelium is indispensable in polymorphonuclear leukocyte (PMN) migration at the site of periodontitis, we examined the effects of gingipains on the expression of ICAM-1 on human oral epithelial cell lines (KB and HSC-2) by flow cytometry and Western blotting. We found that three purified forms of gingipains efficiently reduced ICAM-1 expression on the cells in a time- and dose-dependent manner. Gingipains reduced the expression on fixed cells and degraded the ICAM-1 in the cell membranes, indicating that the reduction resulted from direct proteolysis. They then disturbed the ICAM-1-dependent adhesion of PMNs to the cells. These results indicate that gingipains cleave ICAM-1 on oral epithelial cells, consequently disrupting PMN-oral epithelial cell interaction, and are involved in immune evasion by the bacterium in periodontal tissues.

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