bluuebunny/crossref_metadata_2025_split huggingface dataset:
Friction and wear mechanisms of PA66/PPS blend reinforced with carbon fiber
Authors: Chen Zhaobin , Liu Xujun , Lü Renguo , Li Tongsheng 
Published: March 2007

AbstractThe mechanical and tribological properties of carbon fiber (CF) reinforced polyamide 66 (PA66)/polyphenylene sulfide (PPS) blend composite were studied in this article. It was found that CF reinforcement greatly increases the mechanical properties of PA66/PPS blend. The friction coefficient of the sample decreases with the increase of CF content. When CF content is lower (below 30%), the wear resistance is deteriorated by the addition of CF. However, the loading of higher than 30% CF significantly improves the tribological properties of the blend. The lowest friction coefficient (0.31) and the wear volume (1.05 mm3) were obtained with the PA66/PPS blend containing 30% CF. The transfer film and the worn surface formed by sample during sliding were examined by scanning electron microscopy. The observations revealed that the friction coefficient of PA66/PPS/CF composite depends on the formation and development of a transfer film on the counterface. The abrasive wear caused by ruptured CFs (for lower CF content) and the load bearing ability of CFs (for higher CF content) are the major factors affecting the wear volume. In addition, the improvements of mechanical properties, thermal conductivity, and self‐lubrication of bulk CFs are also contributed to the wear behavior of PA66/PPS/CF composite. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007
Recoverable surface modification using dendritically fluorocarbon‐functionalized poly(methyl methacrylate)
Authors: Thompson Richard L. , Narrainen Amilcar Pillay , Eggleston Stuart M. , Ansari Imtiyaz A. , Hutchings Lian R. , Clarke Nigel 
Published: March 2007

AbstractDendritically fluorocarbon‐functionalized poly(methyl methacrylate) (PMMA) has been explored as a robust surface‐modifying additive in PMMA blends. These functionalized materials, denoted FxPMMAy, where x is the number of C8F17 fluorocarbon groups per dendron connected to a PMMA chain of y kg/mol, have been synthesized by living radical polymerization. These materials adsorb efficiently to the surfaces of their blends with unfunctionalized PMMA, resulting in increased hydrophobicity and lipophobicity. Contact‐angle goniometry has indicated a substantial reduction in the surface energy toward polytetrafluoroethylene‐like surface properties in the case of pure F4PMMA8.6 and substantial, but incomplete fluorocarbon surface coverage at a lower FxPMMAy concentration. The partial coverage has been confirmed by Rutherford backscattering and, together with the weak dependence of the surface modification on the FxPMMAy structure, indicates incomplete equilibrium of the surface adsorption. The modified surfaces are quite durable with respect to abrasion under water but are progressively eroded when the double‐wipe test is carried out with acetone. FxPMMAy, dispersed in the remaining film, acts as a reservoir of spare functional groups, from which the damaged surface may be replenished, leading to the recovery of the modified surface properties. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007
Poly(ϵ‐caprolactone)‐functionalized carbon nanofibers by surface‐initiated ring‐opening polymerization
Authors: Wang Kai , Li Wenwen , Gao Chao 
Published: March 2007

AbstractCarbon nanofibers (CNFs) were covalently functionalized with biodegradable poly(ϵ‐caprolactone) (PCL) by in situ ring‐opening polymerization (ROP) of ϵ‐caprolactone in the presence of stannous octoate. Surface oxidation treatment of the pristine CNFs afforded carboxylic CNFs (CNF‐COOH). Reaction of CNF‐COOH with excess thionyl chloride (SOCl2) and glycol produced hydroxyl‐functionalized CNFs (CNF‐OH). Using CNF‐OH as macroinitiator, PCL was covalently grafted from the surfaces of CNFs by ROP, in either the presence or absence of sacrificial initiator, butanol. The grafted PCL content was achieved as high as 64.2 wt %, and can be controlled to some extent by adjusting the feed ratio of monomer to CNF‐OH. The resulting products were characterized by FTIR, NMR, Raman spectroscopy, TGA, DSC, SEM, TEM, HRTEM, and XRD. Core–shell nanostructures were observed under HRTEM for the PCL‐functionalized CNFs because of the thorough grafting. The PCL‐grafted CNFs showed different melting and crystallization behaviors from the mechanical mixture of PCL and CNF‐OH. This approach to PCL‐functionalized CNFs opens an avenue for the synthesis, modification, and application of CNF‐based nanomaterials and biomaterials. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007
Free volume properties of thermoplastic polyurethane/polymethylmethacrylate blends: Evidence of interchain interaction
Authors: Patrício P. S. O. , Silva G. G. , Machado J. C. 
Published: March 2007

AbstractA polymer blend based on thermoplastic elastomeric polyurethane and polymethylmethacrylate (TPU/PMMA) has been studied by positron annihilation lifetime spectroscopy (PALS) and thermomechanical analysis. Thermomechanical analysis allowed the determination of two glass transitions for the blends in the overall range of compositions. The first one (Tg1) showed a constant value of −45°C for all blends, the same value of the pure TPU. The second glass transition (Tg2), which is associated with a PMMA rich phase, presented variations with composition. Tg2 showed minimum values for the blends in the 20–40 wt % TPU range, which indicates increase of interaction in this composition region. PALS systematic investigation allowed the determination of relative mean free volume fractions, fv/C, and binary interchain interaction parameters, β. These parameters exhibited a noticeable negative deviation from additivity in all range of composition and minima for the 20 wt % TPU blend. PALS results were interpreted as associated to a strong attractive interchain interaction between TPU and PMMA in the PMMA rich phase which contracts the free volume fraction of the blends. Moreover, the miscibility achieved in the PMMA rich phase would allow a good adhesion between this phase and the TPU phase, which was corroborated by scanning electron microscopy images. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007
Composites of polymeric gels and magnetic nanoparticles: Preparation and drug release behavior
Authors: François Nora J. , Allo Sabina , Jacobo Silvia E. , Daraio Marta E. 
Published: March 2007

AbstractThe article is concerned with the preparation of polymer–iron oxide nanocomposites and the study as drug‐delivery matrices under the influence of applied magnetic field. Biocompatible materials were prepared by incorporating an aqueous ferrofluid in poly(vinyl alcohol) and scleroglucan (SCL) hydrogels, loaded with theophylline as model drug for release studies. Thein vitrorelease profile was obtained using a flat Franz cell and the kinetic parameters were derived applying a semiempirical power law. A magnetic characterization of nanoparticles contained in the ferrofluid was performed by obtaining the magnetization curve. For both systems, the observed drug release profiles decreased when a uniform external magnetic field is applied suggesting they can be used as environmental responsive matrices for biomedical applications. Dynamic rheological measurements show that a higher storage modulus and a more compact structure are obtained by incorporating the ferrofluid into the hydrogels. These rheological results and environmental electron scanning microscopy micrographs point to an understanding of release behavior once the magnetic field is applied. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007
Physicochemical properties and fracture behavior of soy‐based resin
Authors: Shabeer A. , Sundararaman S. , Chandrashekhara K. , Dharani L. R. 
Published: March 2007

AbstractA soy‐based resin was prepared by the process of transesterfication and epoxidation of regular food‐grade soybean oil. The soy‐based resin was used as a reactive diluent and also as a replacement of bisA epoxy resin in an anhydride‐cured polymer. The curing efficiency of soy epoxy resin was studied using differential scanning calorimetry. Physicochemical properties and fracture behavior of soy‐based resin polymers were studied using dynamic mechanical analysis and fracture toughness measurements, respectively. Toughness measurements were carried out using the compact tension geometry following the principles of linear elastic fracture mechanics. Tests showed that the addition of soy‐based epoxy resin to the base epon resin improved the toughness of the blend. Morphology of the fractured specimens has been analyzed by scanning electron microscopy. The soy‐based resins hold great potential for environmentally friendly, renewable resource based, and low cost materials for structural applications. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007
Localization, quantification, and characterization of tuftelin in soft tissues
Authors: Leiser Yoav , Blumenfeld Anat , Haze Amir , Dafni Leah , Taylor Angela L. , Rosenfeld Eli , Fermon Eran , Gruenbaum‐Cohen Yael , Shay Boaz , Deutsch Dan 
Published: March 2007

AbstractTuftelin was initially found in the developing and mature extracellular enamel. Here we describe our novel discovery of tuftelin cellular distribution (protein and mRNA) in six soft tissues. The expression levels of tuftelin mRNA were significantly higher in mouse kidney and testis, in which oxygen levels are hovering closely to hypoxia under normal conditions. Anat Rec, 2007. © 2007 Wiley‐Liss, Inc.
High levels of inflammatory chemokines and cytokines in joint fluid and synovial tissue throughout the course of antibiotic‐refractory lyme arthritis
Authors: Shin Junghee J. , Glickstein Lisa J. , Steere Allen C. 
Published: March 2007

AbstractObjectiveTo investigate the possible role of chemokines and cytokines in the pathogenesis of Lyme arthritis.MethodsUsing cytometric bead array and flow cytometry techniques, chemokine and cytokine levels were determined in 65 synovial fluid (SF) samples and 7 synovial tissue (ST) samples from 17 patients with antibiotic‐responsive Lyme arthritis and 35 patients with antibiotic‐refractory Lyme arthritis seen during the past 18 years. In the ST samples, expression of chemokine receptors was measured using immunohistochemistry.ResultsBefore or during antibiotic therapy, when the majority of patients had positive polymerase chain reaction (PCR) results for Borrelia burgdorferi DNA, SF from patients with antibiotic‐refractory arthritis contained exceptionally high levels of Th1 chemoattractants and cytokines, particularly CXCL9 and interferon‐γ (IFNγ). Compared with the patients whose arthritis was responsive to antibiotic treatment, those with antibiotic‐refractory arthritis had significantly higher levels of CXCL9 and CXCL10 (both P ≤ 0.001) and CCL3, CCL4, CXCL8, IFNγ, tumor necrosis factor α, interleukin‐1β (IL‐1β), and IL‐6 (all P ≤ 0.01). During the post‐antibiotic period, when the results of PCR for B burgdorferi DNA in SF and ST were uniformly negative, patients with antibiotic‐refractory arthritis continued to exhibit high SF and ST levels of these chemokines and cytokines. In addition, synovial samples showed marked expression of the receptors for T cell or macrophage chemokines, CXCR3 and CCR5.ConclusionPatients with antibiotic‐refractory Lyme arthritis have high synovial fluid levels of proinflammatory chemokines and cytokines, especially CXCL9 and IFNγ, throughout the illness. Thus, even when antibiotic treatment reduces or completely clears the infection in these patients, the inflammatory response in synovium persists.
Interferon‐γ regulates susceptibility to collagen‐induced arthritis through suppression of interleukin‐17
Authors: Chu Cong‐Qiu , Swart David , Alcorn Dina , Tocker Joel , Elkon Keith B. 
Published: March 2007

AbstractObjectiveThe enhanced expression of experimental arthritis in the absence of interferon‐γ (IFNγ) suggests that IFNγ suppresses arthritis. Interleukin‐17 (IL‐17) is a pivotal T cell cytokine in arthritis, and in vitro studies have indicated that IFNγ suppresses IL‐17 production. We undertook this study to test the hypothesis that resistance to collagen‐induced arthritis (CIA) in C57BL/6 (B6) mice is regulated by IFNγ‐mediated suppression of IL‐17.MethodsWild‐type (WT) B6 mice, IFNγ‐knockout (KO) B6 mice, and DBA/1 mice were immunized with type II collagen (CII) in Freund's complete adjuvant (CFA). Lymphocytes from immunized mice were analyzed for cytokine production ex vivo by intracellular staining or restimulation with CII and enzyme‐linked immunosorbent assays. In vivo blockade of IL‐17 was achieved with an anti–IL‐17 monoclonal antibody (mAb).ResultsCII restimulation of T cells from CII/CFA‐immunized mice resulted in an ∼5‐fold increase in IL‐17 production in IFNγ‐KO B6 mice compared with WT B6 mice. Neutralization of IFNγ increased IL‐17 production in WT B6 mice, and neutralization of IL‐4 had a synergistic effect. Interestingly, the prototypical CIA‐susceptible strain DBA/1 also demonstrated a high IL‐17 and a low IFNγ cytokine profile compared with WT B6 mice. Administration of the anti–IL‐17 mAb attenuated arthritis in DBA/1 mice and almost completely prevented expression of arthritis in IFNγ‐KO B6 mice.ConclusionThese results indicate that sensitivity of IFNγ‐deficient B6 mice to CIA is associated with high IL‐17 production and that this cytokine is required for expression of arthritis in this strain.
Aberrant expression of BAFF by B lymphocytes infiltrating the salivary glands of patients with primary Sjögren's syndrome
Authors: Daridon Capucine , Devauchelle Valérie , Hutin Pascal , Berre Rozenn Le , Martins‐Carvalho Christine , Bendaoud Boutahar , Dueymes Maryvonne , Saraux Alain , Youinou Pierre , Pers Jacques‐Olivier 
Published: March 2007

AbstractObjectiveTo identify the cells that produce BAFF in the salivary glands of patients with primary Sjögren's syndrome (SS), and to analyze BAFF receptor expression by local T and B lymphocytes.MethodsWe used 3 methods to identify the source of BAFF: in situ hybridization of the transcripts for BAFF combined with staining of membrane markers, regular and real‐time reverse transcription–polymerase chain reaction (RT‐PCR) of cultured epithelial cells, and RT‐PCR of sorted single‐cell T and B lymphocytes eluted from salivary glands. Cells expressing TACI, BCMA, and B lymphocyte stimulator receptor 3 (BR‐3) were disclosed by combining each specific staining of the receptors with each specific staining of the cells. The function of BAFF generated by epithelial cells on B lymphocytes was determined in short‐term cocultures.ResultsTranscripts for BAFF were seen in epithelial cells and infiltrating T lymphocytes and, for the first time, were detected in local B cells. It is interesting that BR‐3 was present on these B cells but not on T cells. In contrast, TACI and, to a lesser degree, BCMA were observed on transitional B lymphocytes, whereas T lymphocytes were devoid of receptors for BAFF. Furthermore, this cytokine was shown to be functional, in that epithelial cell–bound BAFF extended the survival of normal B cells, but cell‐free BAFF released in the supernatants did not.ConclusionThese experiments establish that in primary SS, BAFF is produced not only by epithelial cells and T cells but also by B cells. The expression of receptors for BAFF would thus allow these receptors to participate in an autocrine pattern of self‐stimulation.
Arthritic pain is processed in brain areas concerned with emotions and fear
Authors: Kulkarni B. , Bentley D. E. , Elliott R. , Julyan P. J. , Boger E. , Watson A. , Boyle Y. , El‐Deredy W. , Jones A. K. P. 
Published: March 2007

AbstractObjectiveFunctional neuroimaging studies have shown that experimentally induced acute pain is processed within at least 2 parallel networks of brain structures collectively known as the pain matrix. The relevance of this finding to clinical pain is not known, because no direct comparisons of experimental and clinical pain have been performed in the same group of patients. The aim of this study was to compare directly the brain areas involved in processing arthritic pain and experimental pain in a group of patients with osteoarthritis (OA).MethodsTwelve patients with knee OA underwent positron emission tomography of the brain, using 18F‐fluorodeoxyglucose (FDG). Scanning was performed during 3 different pain states: arthritic knee pain, experimental knee pain, and pain‐free. Significant differences in the neuronal uptake of FDG between different pain states were investigated using statistical parametric mapping software.ResultsBoth pain conditions activated the pain matrix, but arthritic pain was associated with increased activity in the cingulate cortex, the thalamus, and the amygdala; these areas are involved in the processing of fear, emotions, and in aversive conditioning.ConclusionOur results suggest that studies of experimental pain provide a relevant but quantitatively incomplete picture of brain activity during arthritic pain. The search for new analgesics for arthritis that act on the brain should focus on drugs that modify this circuitry.
Selective therapeutic control of C5a and the terminal complement complex by anti‐C5 single‐chain Fv in an experimental model of antigen‐induced arthritis in rats
Authors: Fischetti Fabio , Durigutto Paolo , Macor Paolo , Marzari Roberto , Carretta Renzo , Tedesco Francesco 
Published: March 2007

AbstractObjectiveTo determine the role of the terminal complement complex (TCC) in the development of experimental antigen‐induced arthritis (AIA) and the therapeutic effects of human anti‐C5 single‐chain Fv (scFv).MethodsTwo different anti‐C5 scFv, one that inhibits both release of C5a and assembly of the TCC (TS‐A 12/22) and another that selectively blocks formation of the TCC (TS‐A 8), were injected at the onset of AIA. The effects of these scFv on disease severity were evaluated for up to 21 days and compared with the effects of injection of an unrelated scFv. AIA was also established in C6‐deficient and C6‐sufficient PVG rats to obtain further information on the role of the TCC in this model.ResultsTS‐A 12/22 and TS‐A 8 proved to be equally effective in reducing joint swelling, cell counts and tumor necrosis factor α levels in synovial lavage fluids, and the degree of histomorphologic changes compared with the effects of the unrelated scFv. TS‐A 12/22 and TS‐A 8 prevented the deposition of C9 but not that of C3, confirming the ability of the 2 scFv to neutralize C5. Administration of the 2 anti‐C5 scFv after AIA onset also reduced disease severity. In C6‐deficient rats with AIA, disease activity was reduced markedly compared with that in C6‐sufficient rats.ConclusionThese 2 human anti‐C5 scFv could represent potential therapeutic reagents to be used in patients with rheumatoid arthritis. In addition, the finding that TS‐A 8 was as effective as TS‐A 12/22 in reducing disease severity suggests that the TCC is mainly responsible for the joint inflammation and damage observed in AIA.
Light up‐regulated on B lymphocytes and monocytes in rheumatoid arthritis mediates cellular adhesion and metalloproteinase production by synoviocytes
Authors: Kang Young Mo , Kim So Young , Kang Jin Hee , Han Seung Woo , Nam Eon Jeong , Kyung Hee Soo , Park Jae Yong , Kim In San 
Published: March 2007

AbstractObjectiveTo study the expression of LIGHT (tumor necrosis factor superfamily 14) and herpesvirus entry mediator (HVEM; tumor necrosis factor receptor superfamily 14) in rheumatoid arthritis (RA) and to determine the regulatory role of LIGHT on the effector functions of fibroblast‐like synoviocytes (FLS).MethodsThe expression of LIGHT and HVEM was assessed by immunohistochemical staining of synovial tissue and by flow cytometric analysis of mononuclear cells. The presence of HVEM and lymphotoxin β receptor was measured by reverse transcriptase–polymerase chain reaction and by flow cytometry. The regulation of effector molecules, including matrix metalloproteinases (MMPs) and adhesion molecules, was evaluated. The adhesiveness of FLS was determined by adhesion assay.ResultsHVEM was detected in most cell types within rheumatoid synovial tissue, while only a few cells were positive for LIGHT. In RA patients, LIGHT expression was significantly up‐regulated only in CD20+ B cells and monocytes, whereas the mean fluorescence intensity of HVEM was down‐regulated in mononuclear cells. The stimulation of FLS with LIGHT resulted in the production of MMPs and the expression of adhesion molecules, which were efficiently inhibited by dexamethasone. LIGHT‐mediated up‐regulation of MMPs and intercellular adhesion molecule 1 was blocked by inhibitors of NF‐κB and JNK, whereas up‐regulation of vascular cell adhesion molecule 1 was blocked by inhibitors of phosphatidylinositol 3‐kinase, as well as NF‐κB.ConclusionThese data suggest that binding of LIGHT with its receptors may play a role in the progression of inflammation within rheumatoid synovium, especially by mediating the interactions between infiltrating inflammatory cells and stromal cells. These findings thus emphasize the relevance of LIGHT as a potential therapeutic target in RA.
Bone erosions and bone marrow edema as defined by magnetic resonance imaging reflect true bone marrow inflammation in rheumatoid arthritis
Authors: Jimenez‐Boj Esther , Nöbauer‐Huhmann Iris , Hanslik‐Schnabel Beatrice , Dorotka Ronald , Wanivenhaus Axel‐Hugo , Kainberger Franz , Trattnig Siegfried , Axmann Roland , Tsuji Wayne , Hermann Sonja , Smolen Josef , Schett Georg 
Published: March 2007

AbstractObjectiveTo investigate the pathologic nature of features termed “bone erosion” and “bone marrow edema” (also called “osteitis) on magnetic resonance imaging (MRI) scans of joints affected by rheumatoid arthritis (RA).MethodsRA patients scheduled for joint replacement surgery (metacarpophalangeal or proximal interphalangeal joints) underwent MRI on the day before surgery. The presence and localization of bone erosions and bone marrow edema as evidenced by MRI (MRI bone erosions and MRI bone marrow edema) were documented in each joint (n = 12 joints). After surgery, sequential sections from throughout the whole joint were analyzed histologically for bone marrow changes, and these results were correlated with the MRI findings.ResultsMRI bone erosion was recorded based on bone marrow inflammation adjacent to a site of cortical bone penetration. Inflammation was recorded based on either invading synovial tissue (pannus), formation of lymphocytic aggregates, or increased vascularity. Fat‐rich bone marrow was replaced by inflammatory tissue, increasing water content, which appears as bright signal enhancement on STIR MRI sequences. MRI bone marrow edema was recorded based on the finding of inflammatory infiltrates, which were less dense than those of MRI bone erosions and localized more centrally in the joint. These lesions were either isolated or found in contact with MRI bone erosions.ConclusionMRI bone erosions and MRI bone marrow edema are due to the formation of inflammatory infiltrates in the bone marrow of patients with RA. This emphasizes the value of MRI in sensitively detecting inflammatory tissue in the bone marrow and demonstrates that the inflammatory process extends to the bone marrow cavity, which is an additional target structure for antiinflammatory therapy.