bluuebunny/crossref_metadata_2025_split huggingface dataset:
Tribological properties of SiO2 nanoparticle filled–phthalazine ether sulfone/phthalazine ether ketone (50/50 mol %) copolymer composites
Authors: Shao Xin , Tian Jun , Liu Weimin , Xue Qunji , Ma Chunlin 
Published: October 2002

AbstractSiO2 nanoparticle filled–poly(phthalazine ether sulfone ketone) (PPESK) composites with various filler volume fractions were made by heating compression molding. The tribological behavior of the PPESK composites was investigated using a block‐on‐ring test rig by sliding PPESK‐based composite blocks against a mild carbon steel ring. The morphologies of the worn composite surfaces, wear debris, and the transferred films formed on the counterpart steel surface were examined with a scanning electron microscope, whereas the chemical state of the Fe element in the transfer film was analyzed with X‐ray photoelectron spectroscopy. In addition, IR spectra were taken to characterize the structure of wear debris and PPESK composites. It was found that SiO2 nanoparticle filled–PPESK composites exhibit good wear resistance and friction‐reduction behavior. The friction and wear behavior of the composites was improved at a volume fraction between 4.2 and 14.5 vol % of the filler SiO2. The results based on combined SEM, XPS, and IR techniques indicate that SiO2 nanoparticle filled–PPESK composite is characterized by slight scuffing in dry sliding against steel and polishing action between composite surface and that of the countpart ring, whereas unfilled PPESK is characterized by severe plastic deformation and adhesion wear. In the former case a thin, but not complete, transfer film was formed on the surface of the counterpart steel, whereas in the latter case, a thick and lumpy transfer film was formed on the counterpart steel surface. This accounts for the different friction and wear behavior of unfilled PPESK and SiO2 nanoparticle filled–PPESK composites. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 2136–2144, 2002
Rheological behavior of N,N‐dimethyl acrylamide–acrylamido methylpropane sulphonate copolymer
Authors: Sabhapondit Anupom , Sarmah Anujjal , Borthakur Arun , Haque Inamul 
Published: October 2002

AbstractCopolymer of N,N‐dimethylacrylamide (NNDAM) and sodium 2‐acrylamido‐2‐methylpropanesulfonate (NaAMPS) have been prepared by free‐radical copolymerization and characterized with the help of molecular weight, molecular weight distribution, intrinsic viscosity, and monomer ratio in the copolymer. The solution behavior of a copolymer containing 26.62 wt % NaAMPS is studied in different solvents, namely, water (W), dimethyl sulfoxide (DMSO), ethylene glycol (EG), and ethanol (EtOH). The reduced viscosity of the copolymer is highly dependent on the ionic strength of the copolymer solution. The reduced viscosity decreases as a function of solvent selection in the order W > DMSO > EtOH > EG. The shapes of the ηsp / C vs. C plots indicate the polyelectrolyte behavior of the copolymer, except for the case of EG solutions, where nonpolyelectrolyte behavior is observed. However, at a certain degree of ionization attained by adding W as cosolvent, the copolymer begins to demonstrate polyelectrolyte behavior. For this copolymer, there exists a minimum concentration of brine (NaCl, CaCl2, etc.) above which solution viscosity is not further reduced. The copolymer solution behaves as a power law fluid, and exhibits time‐dependent thixotropic behavior. The copolymer cannot regain its solution viscosity when allowed to shear at a constant rate for long period of time. The reduced viscosities of copolymer solutions increase with increasing temperature in W and DMSO, yet decreases with increasing temperature in EG. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 1521–1529, 2002
Preparation of ultrahigh molecular weight syndiotactic poly(vinyl alcohol) microfibrillar fibers by low‐temperature solution polymerization of vinyl pivalate in tertiary butyl alcohol and saponification
Authors: Lyoo Won Seok , Kim Sam Soo , Ghim Han Do , Kim Jae Pil , Lee Sang‐Seob 
Published: October 2002

AbstractVinyl pivalate (VPi) was solution polymerized in tertiary butyl alcohol (TBA) and in dimethyl sulfoxide (DMSO) with a low chain transfer constant using a low temperature initiator, 2,2′‐azobis(2,4‐ dimethylvaleronitrile) (ADMVN). The effects of polymerization temperature and initiator concentration were investigated in terms of polymerization behavior and molecular structures of poly(vinyl pivalate) (PVPi) and its saponification product poly(vinyl alcohol) (PVA). TBA was absolutely superior to DMSO in increasing the syndiotacticity and molecular weight of PVA. In contrast, TBA was inferior to DMSO in causing conversion to polymer, indicating that the initiation rate of VPi production in TBA was lower than that in DMSO. These effects could be explained by a kinetic order of ADMVN concentration, calculated by the initial rate method. Low‐temperature solution polymerization of VPi in TBA or DMSO by adopting ADMVN proved to be successful in obtaining PVA of ultrahigh molecular weight [maximum number‐average degree of polymerization (Pn): 13,500–17,000] and of high yield (ultimate conversion of VPi into PVPi: 55–83%). In the case of bulk polymerization of VPi at the same conditions, maximum Pn and conversion were 14,500–17,500 and 22–36%, respectively. The Pn and syndiotactic diad content were much higher and the degree of branching was lower with PVA prepared from PVPi polymerized at lower temperatures in TBA. Moreover, PVA from the TBA system was fibrous, with a high degree of orientation of the crystallites, indicating the syndiotactic nature of TBA polymerization. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 1992–2003, 2002
The effect of epoxy excess on the kinetics of an epoxy–anhydride system
Authors: Mauri A. N. , Riccardi C. C. 
Published: October 2002

AbstractThe uncatalyzed cure of a commercial tetrafunctional epoxy monomer TGDDM (N,N,N′,N′‐tetraglycidyl‐4,4′‐diaminodiphenylmethane) with hexahydrophthalic anhydride (HHPA), using variable stoichiometric ratios is reported. The reaction was followed by differential scanning calorimetry (DSC). Two kinds of experiments were performed: (1) fresh samples were run at several heating rates, and (2) samples, precured a certain time in an oil bath at constant temperature (i.e., 80 to 120°C), were run at 10°C/min. Two peaks were observed in the case of the epoxy excess but only one for the stoichiometric formulation: the peak at low temperature was attributed to the epoxy copolymerization with the anhydride while the peak at high temperature was attributed to the epoxy homopolymerization. The catalytic effect of the OH groups present in the epoxy monomer on the copolymerization reaction was demonstrated by the decrease in the activation energy of the propagation step when increasing the epoxy excess. There is a catalytic effect of the copolymerization product on the homopolymerization reaction. Our simplest model, proposed previously for a catalyzed epoxy/anhydride system [J. Polym. Sci. Part B: Polym. Phys. Ed., 37, 2799 (1999)], can be used to fit both isothermal and dynamical kinetic data. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 2342–2349, 2002
Properties of rubbery polymers for the recovery of hydrogen sulfide from gasification gases
Authors: Wilks Broderick , Rezac Mary E. 
Published: October 2002

AbstractPolydimethyl siloxane (PDMS) and two polyether‐polyamide copolymers (trade name Pebax) were evaluated for their ability to transport and separate gasification gases. Specifically, the permeabilities of hydrogen, carbon monoxide, carbon dioxide, and hydrogen sulfide were evaluated at temperatures up to 200°C. The permeabilities of all gases were approximately ten times faster through the PDMS than the Pebax materials. The permeabilities through all materials at all temperatures evaluated were H2S > CO2 > H2 > CO. As the temperature increased, the permeabilities of all gases increased through the Pebax. Conversely, for PDMS, hydrogen and carbon monoxide permeabilites increased with temperature while those of H2S and CO2 decreased. The H2S/H2 selectivities ranges from 1.2 (PDMS at 200°C) to 10.3 (Pebax 2533 at 35°C). The activation energies for permeation of these polymer/penetrant pairs are reported. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 2436–2444, 2002
Influences of nonionic poly(ethylene glycol) polymer PEG on electrokinetic and rheological properties of bentonite suspensions
Authors: Ece Ö. I. , Alemdar A. , Güngör N. , Hayashi S. 
Published: October 2002

AbstractThe determination of the electrokinetic properties of colloidal systems is very important for the chracterization of these systems. Colloidal systems have high adsorption performance due to the carrying of negative charges and the colloid structure. The control of the electrokinetic properties of the bentonite–water system are important not only from a technological point view; they are also important from a scientific point of view. Knowing the electrokinetic and rheological properties of bentonite minerals is important for the estimation of the behavior of clays under various environmental conditions. The purpose of this study was to interpret the effect of the nonionic poly(ethylene glycol) (PEG) polymer on electrokinetic and rheological properties. Zeta potential and viscosity measurements were done as a function of PEG molecular weights (400, 3000, and 8000) and their concentrations (2.5 × 10−5 to 1.25 × 10−2 mol/L). We interpreted the experimental data, taking into account these two parameters. X‐ray diffaction studies were done together with the electrokinetic and rheological measurements. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 341–346, 2002
Histochemical and ultrastructural studies of cartilage resorption and acid phosphatase activity during antler growth in fallow deer (Dama dama)
Authors: Szuwart Thomas , Kierdorf Horst , Kierdorf Uwe , Clemen Günter 
Published: October 2002

AbstractCartilage resorption in forming primary fallow deer antlers was studied by histochemistry and electron microscopy. A high activity of tartrate‐resistant acid phosphatase (TRAP), a histochemical marker of skeletal resorbing cells, was first detected in cells located in the mesenchymal tissue separating the columns of hypertrophic cartilage. No cartilage resorption was observed in this region. Intense TRAP staining occurred in large multinucleated cells (identified as inactive osteoclasts) as well as in smaller cells (regarded as mononuclear osteoclast progenitors). On the basis of these findings it was concluded that this was the region where osteoclasts differentiated from progenitor cells. Further proximally, the mineralized cartilage was eroded by active osteoclasts that were located in Howship's lacunae and exhibited an intense TRAP staining. Electron microscopy showed that the cells identified as inactive osteoclasts lacked a polarized organization. In contrast, the active osteoclasts in the zone of cartilage resorption exhibited a typical polarized organization: the nuclei congregated near the basolateral cell surface, and there was a zone of deep membrane infoldings (ruffled border) surrounded by a clear zone at the apical cell pole adjacent to the resorption surface of the mineralized cartilage. The multinucleated cartilage‐resorbing cells of the forming antler thus exhibited the typical histochemical and morphological features of active mammalian osteoclasts. Low levels of TRAP activity were also observed in hypertrophic chondrocytes; however, the specificity and potential significance of this staining remain to be elucidated. Anat Rec 268:66–72, 2002. © 2002 Wiley‐Liss, Inc.
Geoarchaeology of the Milfield Basin, northern England; towards an integrated archaeological prospection, research and management framework
Authors: Passmore David G. , Waddington Clive , Houghton Stephen J. 
Published: October 2002

AbstractThis paper presents the results of geoarchaeological investigations undertaken on the valley floor of the Milfield Basin in Northumberland, northern England. The area has a regionally and nationally important archaeological record, including a series of major neolithic and Anglian settlements, but has hitherto lacked archaeological assessment and management guidelines appropriate to the wide range of late‐glacial and post‐glacial environmental settings in the basin. This project has used geomorphological techniques to delimit and classify a total of nine valley floor landform elements in terms of their geomorphology and their known and potential archaeological and palaeoenvironmental associations.Terraced glaciodeltaic and glaciofluvial sand and gravel landforms comprise the oldest landform elements described here and have formed the primary regional focus for prehistoric and early historic settlement and associated subsistence and ritual activity. These landforms have experienced little post‐glacial geomorphological activity, but their multiperiod archaeological landscapes lie beneath a shallow soil cover and are vulnerable to land‐use activities that disturb terrace soils and underlying sediments. A second group of landform elements are of Holocene age and include localized surface peats, alluvial fans, colluvial deposits and extensive deposits of terraced alluvium. Archaeological landscapes in these environments may lie buried intact and unrecorded beneath protective covers of sediment although locally they may have been subject to erosion and reworking by fluvial and slope processes. Holocene alluviation may account, at least in part, for the paucity of recorded archaeology in these parts of the basin. However, peat and organic‐rich sedimentary sequences identified here (including four 14C dated peat sequences) offer an opportunity to elucidate the environmental context and land‐use histories of local prehistoric and early historic communities in the basin, and hence also should be regarded as an archaeological resource.Discussion of landform elements and their archaeological associations is followed by a brief outline of evaluation criteria developed with the aim of ensuring effective long‐term management of archaeological and palaeoenvironmental resources. It is concluded that geoarchaeological analysis of landform elements may be considered central to development of frameworks intended to underpin future programmes of archaeological research and the development of cultural resource management and evaluation strategies. Copyright © 2002 John Wiley & Sons, Ltd.
Angiostatin gene transfer as an effective treatment strategy in murine collagen‐induced arthritis
Authors: Kim Jong‐Mook , Ho Seong‐Hyun , Park Eun‐Jin , Hahn Woong , Cho Hongchan , Jeong Jae‐Gyun , Lee Yun‐Woo , Kim Sunyoung 
Published: October 2002

AbstractObjectiveTo determine the efficacy of local therapy with human angiostatin gene in murine collagen‐induced arthritis (CIA).MethodsDBA/1 mice were immunized with bovine type II collagen. Before the onset of arthritis, NIH3T3 fibroblasts, transduced with angiostatin‐expressing retroviral vectors or control vectors, were transplanted into the knee cavity. The incidence of arthritis in the knee joints was evaluated histologically based on pannus formation and cartilage destruction. Paws were evaluated macroscopically for redness, swelling, and deformities and immunologically for levels of interleukin‐1β. Angiogenesis in paws and knee joints was studied by immunohistochemistry using anti‐CD31 antibody and measurement of von Willebrand factor levels.ResultsPannus formation and cartilage erosion were dramatically reduced in knees transplanted with angiostatin‐expressing cells. In addition, the onset of CIA in the ipsilateral paws below the knees injected with the angiostatin gene was significantly prevented. Furthermore, angiostatin gene transfer inhibited arthritis‐associated angiogenesis.ConclusionLocal production of angiostatin in the knee was able to prevent the onset of CIA not only in the knee injected with genetically engineered cells, but also in the uninjected ipsilateral paw. This suggests that transfer of the angiostatin gene, and potentially also its protein, may provide a new, effective approach to the treatment of rheumatoid arthritis.
Cyclosporine inhibition of vascular endothelial growth factor production in rheumatoid synovial fibroblasts
Authors: Cho Mi‐La , Cho Chul‐Soo , Min So‐Youn , Kim Seung‐Hoon , Lee Shin‐Seok , Kim Wan‐Uk , Min Do‐June , Min Jun‐Ki , Youn Jeehee , Hwang Sue‐Yun , Park Sung‐Hwan , Kim Ho‐Youn 
Published: October 2002

AbstractObjectiveTo determine the antiangiogenic effect of cyclosporin A (CSA) in rheumatoid arthritis (RA).MethodsWe investigated the effect of CSA on the production of vascular endothelial growth factor (VEGF) by rheumatoid synovial fibroblasts. Fibroblast‐like synoviocytes (FLS) were prepared from the synovial tissues of RA patients, and cultured in the presence of CSA. The production of VEGF by FLS was measured in culture supernatants by enzyme‐linked immunosorbent assay. The VEGF messenger RNA (mRNA) expression and activator protein 1 (AP‐1) binding activity for VEGF transcription were determined by polymerase chain reaction and electrophoretic mobility shift assay, respectively.ResultsCSA dose‐dependently inhibited both constitutive and transforming growth factor β‐induced VEGF production at the protein and mRNA levels. The suppressive action of CSA on VEGF synthesis was calcineurin dependent, as evidenced by a comparable inhibition by FK‐506. Agonists of cAMP, 3‐isobutyl‐1‐methylxanthine and N‐2‐O‐dibutyryl‐cAMP, mimicked the effect of CSA on VEGF production, while a cAMP antagonist, 2′,3′‐dideoxyadenosine, abrogated the effect of CSA. A gel mobility shift assay showed that the inhibitory effect of CSA was associated with decreased AP‐1 binding activity to the VEGF promoter, in a cAMP‐dependent manner.ConclusionCSA may exert an antiangiogenic effect by inhibiting AP‐1‐mediated VEGF expression in rheumatoid synovial fibroblasts.
Viral interleukin‐10 gene inhibition of inflammation, osteoclastogenesis, and bone resorption in response to titanium particles
Authors: Carmody Emily E. , Schwarz Edward M. , Puzas J. Edward , Rosier Randy N. , O'Keefe Regis J. 
Published: October 2002

AbstractObjectiveTo evaluate the potential of viral interleukin‐10 (vIL‐10) gene therapy as an approach to prevent wear debris–induced inflammation, osteoclastogenesis, and bone resorption as it relates to periprosthetic osteolysis in patients with total joint replacements.MethodsReplication‐defective adenovirus vectors expressing vIL‐10 (AdvIL‐10) or LacZ (AdLacZ) target genes were used to transduce fibroblast‐like synoviocytes (FLS) in vitro, and the effects of these cells on wear debris–induced proinflammatory cytokine production and receptor activator of nuclear factor κB ligand + macrophage colony‐stimulating factor splenocyte osteoclastogenesis were assessed by enzyme‐linked immunosorbent assay and tartrate‐resistant acid phosphatase assay. The effects of AdvIL‐10 administration on wear debris–induced osteolysis in vivo were analyzed using the mouse calvaria model, in which AdLacZ was used as the control.ResultsIn the presence of AdLacZ‐infected FLS, titanium particle–stimulated macrophages exhibited a marked increase in secretion of tumor necrosis factor α (TNFα) (6.5‐fold), IL‐6 (13‐fold), and IL‐1 (5‐fold). Coculture with AdvIL‐10–transduced FLS suppressed cytokine secretion to basal levels, while addition of an anti–IL‐10 neutralizing antibody completely blocked this effect. The vIL‐10–transduced FLS also inhibited osteoclastogenesis 10‐fold in an anti–IL‐10–sensitive manner. In vivo, titanium implantation resulted in a 2‐fold increase in osteoclasts (P < 0.05) and in a 2‐fold increase in sagittal suture area (P < 0.05). This increase over control levels was completely blocked in mice receiving intraperitoneal injections of AdvIL‐10, all of whom had measurable serum vIL‐10 levels for the duration of the experiment. Immunohistochemistry demonstrated reduced cyclooxygenase 2 and TNFα expression in AdvIL‐10–infected animals.ConclusionThis study demonstrates that gene delivery of vIL‐10 inhibits 3 processes critically involved in periprosthetic osteolysis: 1) wear debris–induced proinflammatory cytokine production, 2) osteoclastogenesis, and 3) osteolysis.
Fcγ receptor gene polymorphisms in Japanese patients with systemic lupus erythematosus: Contribution of FCGR2B to genetic susceptibility
Authors: Kyogoku Chieko , Dijstelbloem Hilde M. , Tsuchiya Naoyuki , Hatta Yoko , Kato Hitoshi , Yamaguchi Akihiro , Fukazawa Toru , Jansen Marc D. , Hashimoto Hiroshi , van de Winkel Jan G. J. , Kallenberg Cees G. M. , Tokunaga Katsushi 
Published: October 2002

AbstractObjectiveHuman low‐affinity Fcγ receptors (FcγR) constitute a clustered gene family located on chromosome 1q23, that consists of FcγRIIA, IIB, IIC, IIIA, and IIIB genes. FcγRIIB is unique in its ability to transmit inhibitory signals, and recent animal studies demonstrated a role for FcγRIIB deficiency in the development of autoimmunity. Genetic variants of FcγRIIA, IIIA, and IIIB and their association with systemic lupus erythematosus (SLE) have been extensively studied in various populations, but the results were inconsistent. To examine the possibility that another susceptibility gene of primary significance exists within the FcγR region, we screened for polymorphisms of the human FCGR2B gene, and examined whether these polymorphisms are associated with SLE.MethodsVariation screening of FCGR2B was performed by direct sequencing and polymerase chain reaction (PCR)‐single‐strand conformation polymorphism methods using complementary DNA samples. Genotyping of the detected polymorphism was done using genomic DNA, with a specific genotyping system based on nested PCR and hybridization probing. Association with SLE was analyzed in 193 Japanese patients with SLE and 303 healthy individuals. In addition, the same groups of patients and controls were genotyped for the previously known polymorphisms of FCGR2A, FCGR3A, and FCGR3B.ResultsWe detected a single‐nucleotide polymorphism in FCGR2B, (c.695T>C), coding for a nonsynonymous substitution, Ile232Thr (I232T), within the transmembrane domain. The frequency of the 232T/T genotype was significantly increased in SLE patients compared with healthy individuals. When the same patients and controls were also genotyped for FCGR2A‐131R/H, FCGR3A‐176V/F, and FCGR3B‐NA1/2 polymorphisms, FCGR3A‐176F/F showed significant association. Two‐locus analyses suggested that both FCGR2B and FCGR3A may contribute to SLE susceptibility, while the previously reported association of FCGR3B was considered to be secondary and derived from strong linkage disequilibrium with FCGR2B.ConclusionThese results demonstrate the association of a new polymorphism of FCGR2B (I232T) with susceptibility to SLE in the Japanese.