bluuebunny/crossref_metadata_2025_split huggingface dataset:
Characterization of polyaniline via pyrolysis mass spectrometry
Authors: Hacaloglu Jale , Argin Emir , Kücükyavuz Zühal 
Published: December 2007

AbstractIn this work, direct insertion probe pyrolysis mass spectrometry technique was applied to investigate the thermal and the structural characteristics of electrochemically prepared HCl and HNO3‐doped polyaniline (PANI) films. It has been determined that the thermal degradation of both samples showed three main thermal degradation stages. The first stage around 50–60°C was associated with evolution of solvent and low‐molecular‐weight species adsorbed on the polymer, the second stage just above 150°C was attributed to evolution of dopant‐based products, and the final degradation stage at moderate and elevated temperatures was associated with evolution of degradation products of the polymer. Chlorination and nitrolysis of aniline during the electrochemical polymerization were detected. Extent of substitution increased as the electrolysis period was increased. Furthermore, for the HNO3‐doped PANI, the evolution of CO2 at elevated temperatures confirmed oxidation of the polymer film during electrolysis. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Preparation and characterization of high‐impact polystyrene using different types of polybutadiene
Authors: Coutinho F. M. B. , Costa M. P. M. , Guimarães M. J. O. C. , Soares B. G. 
Published: December 2007

AbstractThe mechanical, morphological, and rheological properties of polymer blends based on polystyrene (PS) and three different types of polybutadiene (PB) were studied. The polymer blends containing 20% of PB were processed in a Haake mixer at 180°C and 60 rpm for 6 min. The materials exhibited impact strength superior to that of the PS. An increase was observed in the impact strength of 138, 208, and 823%, when low‐cis polybutadiene (PBl), high‐cis polybutadiene (PBh), and styrene–butadiene block copolymer (PBco), were respectively used. The materials presented dispersed morphology with polybutadiene domains, with sizes inferior to 1 μm, randomly distributed in the PS matrix. The viscous and storage moduli increased as the applied frequency increased. The flow activation energy, calculated by Arrhenius equation, varied from 34 to 71 kJ/mol. In the rheological experiments all polymer blends presented pseudoplastic behavior, showing decreasing viscosities as the shear rate increased. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Compatibilization efficiency of styrene‐butadiene block copolymers as a function of their block number
Authors: Vranješ Nina , Lednický František , Kotek Jiří , Baldrian Josef , Rek Vesna , Fortelný Ivan , Horák Zdeněk 
Published: December 2007

AbstractEffect of block number in linear styrene‐butadiene (SB) block copolymers (BCs) on their compatibilization efficiency in blending polystyrene (PS) with polybutadiene (PB) was studied. Di‐, tri‐, or pentablocks of SB copolymers as well as their combinations were blended with the mentioned homopolymers; supramolecular structure determined by small angle X‐ray scattering method (SAXS), morphology using scanning electron microscopy (SEM) combined with image analysis (IA), and stress transfer characteristics of the blends were chosen as criteria of compatibilization efficiency of the copolymers used. It was proved that the addition of SB BCs led to remarkably finer phase structure and substantially higher toughness of PS/PB blends. Triblock copolymer showed to be the compatibilizer with higher efficiency than diblock, pentablock, and the di/triblock copolymer mixture. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Thermal stability and decomposition mechanism of poly(p‐acryloyloxybenzoic acid and poly (p‐methacryloyloxybenzoic acid) and their graft copolymers with polypropylene, Part II
Authors: Çetin S. , Tinçer T. 
Published: December 2007

AbstractThermal stability and decomposition mechanism of poly(p‐acryloyloxybenzoic) acid (PABA), p‐methacryloyloxybenzoic acid (PMBA), and their graft coproducts of PP were studied by differential scanning calorimetry, direct pyrolysis mass spectrometry, and TG/IR system, combined thermogravimetric analyzer, and FTIR spectrometer. The homopolymers and corresponding grafts were found to be stable in nitrogen atmosphere but started to decompose under atmospheric conditions when heated above 230°C. PABA and PAPA‐g‐PP showed a better thermal stability compared to the other polymer. The degradation proceeded predominantly by decomposition of side groups giving phenol, benzoic acid, hydroxybenzoic acid, carboxylic and carbonyl groups, and by decomposition of phenol into cyclodiene mainly. It was also seen that the degradation path did not greatly changed whether the PABA or PMBA were homopolymers or grafted onto PP but the induction temperature of grafted polymers was seen at some 10–20°C higher. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Chemoenzymatic synthesis, characterization, and controlled release of functional polymeric prodrugs with acyclovir as pendant
Authors: Li Xia , Wu Qi , Zhang Fu , Lin Xian‐Fu 
Published: December 2007

AbstractAn efficient protocol for the synthesis of functional polymeric prodrugs of acyclovir with variable copolymer composition and potential liver‐targeting delivery was achieved by combining enzymatic selective synthesis of polymerizable acyclovir derivatives with radical copolymerization of properly selected comonomers. Vinyl D‐galactose ester (VAG), acrylic acid (AA), and methyl methacrylate (MMA) were chosen as comonomers and three novel polymeric prodrugs with acyclovir as pendant were synthesized using 2,2′‐azo‐bis‐iso‐butyronitrile (AIBN) as initiator in N,N‐dimethylformamide (DMF). The resulting polymers were characterized by FTIR, NMR, and GPC. The influence of the concentration of initiator and the molar ratio of comonomers on the polymerization was investigated. In vitro drug release studies showed that acyclovir could be released from poly(2‐N‐vinylsebacyl‐acyclovir‐co‐methyl methacrylate) (poly(VSA‐co‐MMA)), and the total released acyclovir after 7 days in buffer solution at pH 1.2 and 7.4 was ∼ 35% and 29%, respectively. Also, homopolymers of vinyl acyclovir derivatives with high drug payload (>50 wt %) were obtained and characterized by the same methods. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Studies of adsorption of alkaline trypsin by poly(methacrylic acid) brushes on chitosan membranes
Authors: Bayramoğlu Gülay , Erdogan Hakan , Arica M. Yakup 
Published: December 2007

AbstractPoly(methacrylic acid)‐grafted chitosan membranes (chitosan‐g‐poly(MAA)) were prepared in two sequential steps: in the first step, chitosan membranes were prepared by phase‐inversion technique and then epichlorohydrin was used as crosslinking agent to increase its chemical stability in acidic media; in the second step, the graftcopolymerization of methacrylic acid onto the chitosan membranes was initiated by ammonium persulfate (APS) under nitrogen atmosphere. The chitosan‐g‐poly(MAA) membranes were first used as an ion‐exchange support for adsorption of trypsin from aqueous solution. The influence of pH, equilibrium time, ionic strength, and initial trypsin concentration on the adsorption capacity of the chitosan‐g‐poly(MAA) membranes have been investigated in a batch system. Maximum trypsin adsorption onto chitosan‐g‐poly(MAA) membrane was found to be 92.86 mg mL−1 at pH 7.0. The experimental equilibrium data obtained for trypsin adsorption onto chitosan‐g‐poly(MAA) membranes fitted well to the Langmuir isotherm model. The adsorption data was analyzed using the first‐ and second‐order kinetic models, and the experimental data was well described by the second‐order equation. More than 97% of the adsorbed trypsin was desorbed using glutamic acid solution (0.5M, pH 4.0). In addition, the chitosan‐g‐ poly(MAA) membrane prepared in this work showed promising potential for various biotechnological applications. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Differential expression of CYP6A5 and CYP6A5v2 in pyrethroid‐resistant house flies, Musca domestica
Authors: Zhu Fang , Liu Nannan 
Published: December 2007

AbstractTwo cytochrome P450 alleles, CYP6A5 and CYP6A5v2, were isolated from a pyrethroid‐resistant house fly stain, ALHF. The two alleles shared 98% similarity in amino acid sequence. To understand the importance of these two alleles in resistance and examine the expression profile of the two alleles between resistant and susceptible strains, quantitative real‐time PCR (qRT‐PCR) was performed and compared with the Northern blot analysis. We found that qRT‐PCR was an efficient method to characterize the expression profiles between these two sequence‐closely‐related P450 genes between resistant and susceptible houses flies. One of them, CYP6A5v2, was constitutively overexpressed in ALHF house flies compared with susceptible house fly strains. Moreover, this gene was predominately expressed in the abdominal tissues of ALHF, in which the primary detoxification organs of insects are located. However, there was no significant difference in the expression of CYP6A5 between ALHF and susceptible house flies. The genetic linkage analysis was conducted to determine the possible link between the constitutively overexpressed CYP6A5v2 and insecticide resistance. CYP6A5v2 was mapped on autosome 5, which is correlated with the linkage of resistance in ALHF. Taken together, the study suggests the importance of CYP6A5v2 in increasing metabolic detoxification of insecticides in ALHF. The distinct expression of CYP6A5 and CYP6A5v2 in resistant and susceptible house flies implies the functional difference of theses two genes in house flies and suggests that they are two recently diverged P450 genes presented in a single organism. Arch. Insect Biochem. Physiol. 2007. © 2007 Wiley‐Liss, Inc.
cDNA cloning, characterization, and developmental expression of the 20S proteasome α5 subunit in the Mediterranean fruit fly Ceratitis capitata
Authors: Verras Meletios , Gourzi Polyxeni , Kalosaka Katerina , Zacharopoulou Antigone , Mintzas Anastassios C. 
Published: December 2007

AbstractIn the present study, we report the cDNA cloning, characterization, and developmental expression of the 20S proteasome α5 subunit from the Mediterranean fruit fly Ceratitis capitata (medfly). Using an RT‐PCR fragment that corresponds to the amino‐terminal region of the Drosophila melanogaster 20S proteasome α5 subunit, we isolated a 987‐bp cDNA that encodes the complete coding region of the medfly ortholog, which was named CcPSMA5. CcPSMA5 consists of 241 amino acids and has a predicted molecular weight of 26.4 kDa and pI 4.75. Comparison of the CcPSMA5 amino acid sequence with the sequences of all known 20S proteasome α5 subunits from different organisms indicated that the medfly 20S proteasome α5 subunit has the strongest homology to that of Drosophila. In situ hybridization showed that the CcPSMA5 gene is mapped in the region 44B of chromosome 4. Northern blot hybridization analysis showed that the CcPSMA5 mRNA has a size of approximately 1.2 kb. High levels of the CcPSMA5 mRNA were detected in freshly laid eggs, indicating that they were maternally deposited. The mRNA expression pattern during medfly development suggests that the CcPSMA5 gene is upregulated before mid‐embryogenesis and at the onset of metamorphosis. Arch. Insect Biochem. Physiol. © 2007 Wiley‐Liss, Inc.
Novel cytochrome P450s, CYP6BB1 and CYP6P10, from the salt marsh mosquito Aedes sollicitans (Walker) (Diptera: Culicidae)
Authors: Huang Shaoming , Sun Debin , Brattsten L. B. 
Published: December 2007

AbstractBased on the conserved heme‐binding region and the charge pair consensus of insect cytochrome P450s, two novel full‐length P450 cDNAs, CYP6BB1 and CYP6P10, were cloned from the salt marsh mosquito Aedes sollicitans (Walker). CYP6BB1 and CYP6P10 had open reading frames of 1,518 and 1,521 nucleotides encoding 506 and 507 amino acid residue proteins, respectively. Several alleles with amino acid substitutions were found both in CYP6BB1 and CYP6P10. The deduced proteins are typical microsomal P450s sharing signature sequences with other insect CYP6 P450s. Sequence analysis showed that both CYP6BB1 and CYP6P10 shared highest sequence identities with P450 CYP6P4, 56% and 65%, respectively. Phylogenetic analysis showed both CYP6BB1 and CYP6P10 were grouped into the clade containing several P450s from subfamily CYP6P. Real‐time RT‐PCR analysis showed CYP6BB1 but not CYP6P10 transcription in females was significantly increased 24 h after a blood meal. Neither CYP6BB1 nor CYP6P10 were life stage or gender specific. Protein expression experiments are needed to determine the functions of these proteins. Arch. Insect Biochem. Physiol. 2007. © 2007 Wiley‐Liss, Inc.
Arthritogenic antibodies specific for a major type II collagen triple‐helical epitope bind and destabilize cartilage independent of inflammation
Authors: Nandakumar Kutty Selva , Bajtner Estelle , Hill Leigh , Böhm Beate , Rowley Merrill J. , Burkhardt Harald , Holmdahl Rikard 
Published: December 2007

AbstractObjectiveTo investigate the significance and pathogenic potential of a highly conserved major type II collagen triple‐helical epitope–specific antibody (U1; amino acids 494–504) in vivo and in vitro in patients with early rheumatoid arthritis (RA) and in experimental animal models of collagen‐induced arthritis (CIA).MethodsU1‐specific antibodies in sera from patients with early RA (with or without joint erosions) were analyzed. Disease progression in the CIA models in mice and rats with anti‐U1 antibodies was compared. The pathogenicity of binding of monoclonal antibodies (mAb) UL1 and CIIF4 to the U1 epitope and the F4 epitope (aa 926–936), respectively, was compared in vivo and on chondrocyte cultures and preformed cartilage in vitro, using Fourier transform infrared microspectroscopy analysis. In addition, UL1‐induced proteoglycan depletion in vivo in the presence and absence of the complement factor C5 was analyzed.ResultsIncreased levels of U1 antibodies were observed in patients with early RA, especially in association with joint erosions. A significant correlation of U1‐specific antibodies with disease progression was found in rats and mice with CIA. UL1 mAb induced, whereas CIIF4 mAb inhibited, the progression of arthritis. Similarly, UL1, but not CIIF4, impaired matrix synthesis on chondrocyte cultures and adversely affected preformed cartilage. Furthermore, UL1 induced significant proteoglycan depletion in vivo 3 days after injection, even in the absence of C5.ConclusionAntibody epitope specificity contributes significantly to the development of arthritis, and the early pathogenic events operate independent of inflammation both in vitro and in vivo.
Abnormal tumor necrosis factor receptor I cell surface expression and NF‐κB activation in tumor necrosis factor receptor–associated periodic syndrome
Authors: Nedjai Belinda , Hitman Graham A. , Yousaf Nasim , Chernajovsky Yuti , Stjernberg‐Salmela Susanna , Pettersson Tom , Ranki Annamari , Hawkins Philip N. , Arkwright Peter D. , McDermott Michael F. , Turner Mark D. 
Published: December 2007

AbstractObjectiveTumor necrosis factor receptor–associated periodic syndrome (TRAPS) is an autosomal‐dominant autoinflammatory condition caused by mutations in the TNFRSF1A gene. The cellular mechanisms by which mutations in this gene trigger inflammation are currently unclear. Because NF‐κB is the major intracellular signaling component inducing secretion of proinflammatory cytokines, we sought to determine whether differences in the clinical phenotype of patients with TRAPS may be attributable to variable effects of TNFRSF1A mutations on TNFRI expression, localization, or NF‐κB activity.MethodsPeripheral blood mononuclear cells were obtained from patients (following informed consent), and cellular nuclear and cytosolic fractions were generated by subcellular fractionation. Localization of IκBα and NF‐κB was determined by Western blotting of the resultant fractions. NF‐κB subunit activity was determined by enzyme‐linked immunosorbent assay analysis and confirmed by electrophoretic mobility shift assay. Subcellular localization of TNFRI was determined by immunofluorescence confocal microscopy or by immunoblotting following affinity isolation of plasma membrane by subcellular fractionation.ResultsCells from patients with the fully penetrant C73R mutation had marked activation of the proinflammatory p65 subunit of NF‐κB. In contrast, cells from patients with the low‐penetrant R92Q mutation displayed high levels of DNA binding by the p50 subunit, an interaction previously linked to repression of inflammation. Interestingly, although cells from patients with the C73R mutation have no TNFRI shedding defect, there was nonetheless an unusually high concentration of functional TNFRI at the plasma membrane.ConclusionHigh levels of TNFRI at the cell surface in patients with the C73R mutation hypersensitizes cells to stimulation by TNF, leading to increased NF‐κB p65 subunit activation and an exaggerated proinflammatory response.
A biomarker‐based mathematical model to predict bone‐forming potency of human synovial and periosteal mesenchymal stem cells
Authors: De Bari Cosimo , Dell'Accio Francesco , Karystinou Alexandra , Guillot Pascale V. , Fisk Nicholas M. , Jones Elena A. , McGonagle Dennis , Khan Ilyas M. , Archer Charles W. , Mitsiadis Thimios A. , Donaldson Ana Nora , Luyten Frank P. , Pitzalis Costantino 
Published: December 2007

AbstractObjectiveTo develop a biomarker‐based model to predict osteogenic potency of human mesenchymal stem cells (MSCs) from synovial membrane and periosteum.MethodsMSC populations were derived from adult synovium and periosteum. Phenotype analysis was performed by fluorescence‐activated cell sorting and real‐time reverse transcriptase–polymerase chain reaction (RT‐PCR). Telomere lengths were determined by Southern blot analysis. In vitro osteogenesis was assessed quantitatively by measurements of alkaline phosphatase activity and calcium deposits. To investigate bone formation in vivo, MSCs were seeded onto osteoinductive scaffolds and implanted subcutaneously in nude mice. Bone was assessed by histology, and the human origin investigated by in situ hybridization for human Alu genomic repeats. Quantitation was achieved by histomorphometry and real‐time RT‐PCR for human osteocalcin. Analysis at the single‐cell level was performed with clonal populations obtained by limiting dilution. Multiple regressions were used to explore the incremental predictive value of the markers.ResultsPeriosteal MSCs had significantly greater osteogenic potency than did synovial MSCs inherent to the single cell. Bone was largely of human origin in vivo. Within the same tissue type, there was variability between different donors. To identify predictors of osteogenic potency, we measured the expression levels of osteoblast lineage genes in synovial and periosteal clonal MSCs prior to osteogenic treatment. We identified biomarkers that correlated with osteogenic outcome and developed a mathematical model based on type I collagen and osteoprotegerin expression that predicts the bone‐forming potency of MSC preparations, independent of donor‐related variables and tissue source.ConclusionOur findings indicate that our quality‐control mathematical model estimates the bone‐forming potency of MSC preparations for bone repair.
Comparison of the clinical efficacy and safety of subcutaneous versus oral administration of methotrexate in patients with active rheumatoid arthritis: Results of a six‐month, multicenter, randomized, double‐blind, controlled, phase IV trial
Authors: Braun J. , Kästner P. , Flaxenberg P. , Währisch J. , Hanke P. , Demary W. , von Hinüber U. , Rockwitz K. , Heitz W. , Pichlmeier U. , Guimbal‐Schmolck C. , Brandt A. ,   MC‐MTX.6/RH Study Group
Published: December 2007

AbstractObjectiveTo compare the efficacy and safety of subcutaneous (SC) versus oral administration of methotrexate (MTX) in patients with active rheumatoid arthritis (RA).MethodsMTX‐naive patients with active RA (Disease Activity Score in 28 joints ≥4) were eligible for the study if they had not previously taken biologic agents and had not taken disease‐modifying antirheumatic drugs for 2 weeks prior to randomization. Patients were randomly assigned to receive 15 mg/week of MTX either orally (2 7.5‐mg tablets plus a dummy prefilled syringe; n = 187 patients) or SC (prefilled syringe containing 10 mg/ml plus 2 dummy tablets; n = 188 patients) for 24 weeks. At week 16, patients who did not meet the American College of Rheumatology criteria for 20% improvement (ACR20) were switched from 15 mg of oral MTX to 15 mg of SC MTX and from 15 mg of SC MTX to 20 mg of SC MTX for the remaining 8 weeks, still in a blinded manner. The primary outcome was an ACR20 response at 24 weeks.ResultsAt week 24, significantly more patients treated with SC MTX than with oral MTX showed ACR20 (78% versus 70%) and ACR70 (41% versus 33%) responses. Patients with a disease duration ≥12 months had even higher ACR20 response rates (89% for SC administration and 63% for oral). In 52 of the ACR20 nonresponders (14%), treatment was switched at week 16. Changing from oral to SC MTX and from 15 mg to 20 mg of SC MTX resulted in 30% and 23% ACR20 response rates, respectively, in these patients. MTX was well tolerated. The rate of adverse events was similar in all groups.ConclusionThis 6‐month prospective, randomized, controlled trial is the first to examine oral versus SC administration of MTX. We found that SC administration was significantly more effective than oral administration of the same MTX dosage. There was no difference in tolerability.
T cell dependence of chronic destructive murine arthritis induced by repeated local activation of toll‐like receptor–driven pathways: Crucial role of both interleukin‐1β and interleukin‐17
Authors: Joosten Leo A. B. , Abdollahi‐Roodsaz Shahla , Heuvelmans‐Jacobs Marleen , Helsen Monique M. A. , van den Bersselaar Liduine A. M. , Oppers‐Walgreen Birgitte , Koenders Marije I. , van den Berg Wim B. 
Published: December 2007

AbstractObjectiveThe pathogenesis of rheumatoid arthritis is often linked to bacterial infections. The present study was undertaken to develop a mouse model of chronic destructive arthritis induced by repeated intraarticular (IA) exposure to bacterial cell wall fragments and to investigate the cytokine dependence of this model.MethodsMice that were deficient in various cytokines were injected IA with cell wall fragments of Streptococcus pyogenes on days 0, 7, 14, and 21. The development of chronic destructive arthritis was compared between groups of mice lacking different cytokines, to assess which cytokines were crucial for development of chronic destructive arthritis.ResultsRepeated exposure of a joint to S pyogenes cell wall fragments resulted in the development of chronic destructive arthritis. In mice deficient in recombination‐activating gene 2, streptococcal cell wall (SCW)–directed T cell reactivity was found and chronic arthritis did not develop, implicating T cells in the generation of chronic SCW‐induced arthritis. Interleukin‐17 (IL‐17) receptor–deficient mice showed a reduction of joint destruction in the chronic stage, implicating a detrimental role of the recently discovered IL‐17–producing T helper cells (Th17 cells). IL‐23 expression was apparent during the late stages of arthritis. Joint swelling was no longer dependent on tumor necrosis factor α (TNFα) after the last flare, and pronounced cartilage damage was found after 28 days in TNFα‐deficient mice. In contrast, IL‐1β–deficient mice were fully protected against joint swelling and cartilage and bone destruction during the late stages of disease.ConclusionThese findings indicate that the TNFα dependence of arthritis is lost during the erosive stage, when Th17 cells become crucial. IL‐1β dependence remains strong, consistent with its pivotal role in the generation of Th17 cells.