bluuebunny/crossref_metadata_2025_split huggingface dataset:
A new polymerization method and kinetics for acrylamide: Aqueous two‐phase polymerization
Authors: Guorong Shan , Zhihai Cao 
Published: October 2008

AbstractThe concept of aqueous two‐phase polymerization and a new polymerization method for the preparation of water‐soluble polymers are presented. The phase diagram of poly(acrylamide) (PAAm)‐poly (ethylene glycol) (PEG)‐water two‐phase system was measured by the gel permeation chromatography (GPC). The aqueous two‐phase of PAAm‐PEG‐water system can be easily formed. The critical concentration of phase separation was affected by the molecular weight of PEG. The aqueous two‐phase polymerization of acrylamide (AAm) has been successfully carried out in the presence of PEG by using ammonium persulfate (APS) as the initiator. The polymerization behaviors with varying concentration of AAm, initiator and PEG, the polymerization temperature, the molecular weight of PEG, and emulsifier types were investigated. The activation energy of aqueous two‐phase polymerization of AAm was 132.3 kJ/mol. The relationship of initial polymerization rate (Rp0) with APS and AAm concentrations was Rp0 ∝ [APS]0.72 [AAm]1.28. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Crystallization behavior and mechanical properties of crosslinked plasticized poly(L‐lactic acid)
Authors: Jia Zhiyuan , Zhang Kunyu , Tan Juanjuan , Han Changyu , Dong Lisong , Yang Yuming 
Published: October 2008

AbstractEnhancing the stability of plasticized poly(L‐lactic acid) (PLLA) with poly (ethylene glycol) (PEG) is necessary for its practical application. In this study, plasticized PLLA (PLLA/PEG 80/20 wt/wt) was crosslinked under γ‐ray (Co60) in the presence of triallyl isocyanurate (TAIC) as crosslinking agent. FTIR analysis revealed that PLLA, PEG, and TAIC formed a cocrosslinking structure. Crystallization behavior and mechanical properties of the crosslinked plasticized PLLA were investigated by differential scanning calorimetry (DSC), wide‐angle X‐ray diffraction (WAXD), scanning electron microscopy (SEM), and tensile tests. Experimental results indicated that the crystallization behaviors of both PEG and PLLA in the blends were restrained after irradiation. The melting peak of PEG in the crystallized samples disappeared at a low irradiation doses about 10 kGy. Although PLLA still owned the behavior of crystallize, its cold crystallization temperature and glass transition temperature shifted to higher temperature. Mechanical properties of the plasticized PLLA were strengthened through crosslinking. Both yield strength and elastic modulus of the samples increased after crosslinking. Elongation at break of the crosslinked plasticized PLLA decreased with the increase of crosslinking density but remained a high value over 200%. SEM images of fracture surfaces confirmed that the ductile fracture behavior of plasticized PLLA was kept after suitable crosslinking. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Preparation and thermal characterization of poly(ethylene oxide)/griseofulvin solid dispersions for biomedical applications
Authors: Stachurek Iwona , Pielichowski Krzysztof 
Published: October 2008

AbstractIn this work, a series of poly(ethylene oxide)/griseofulvin (PEO/gris) solid dispersions has been prepared and characterized by PLM, FTIR, DSC, and MT‐DSC. It has been found that the crystalline phase morphology depends strongly on the PEO molecular weight and, in the PEO/gris systems, griseofulvin molecules stay in amorphous phase of PEO, which enhances the solubility of a drug and increases its biological access. For PEO‐drug systems containing 5, 10, and 15% gris, FTIR bands due to stretching vibrations of the OH groups were found at 3436, 3436, and 3413 cm−1, respectively, whereby for pure PEO 3400, they were located at 3513 cm−1—the observed shift proves the existence of hydrogen bonds between PEO and griseofulvin. The presence of griseofulvin caused lowering of the systems' melting temperature in the whole concentration range and, as evidenced by MT‐DSC results, recrystallization of PEO in the PEO/griseofulvin systems during melting does occur. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Thermal and crystallinity property studies of poly (L‐lactic acid) blended with oligomers of 3‐hydroxybutyrate or dendrimers of hydroxyalkanoic acids
Authors: Ni Chengyang , Luo Rongcong , Xu Kaitian , Chen Guo‐Qiang 
Published: October 2008

AbstractPoly (L‐lactic acid) (PLA) is a biodegradable polymer with slow crystallization rate. Oligomers of 3‐hydroxybutyrate (OHB) and dendrimers of hydroxyalkanoic acids with different molecular weights were blended with PLA in a hope to improve the crystallization ability and thermal stability of PLA, respectively. Four thermally‐degraded PHB products oligomers termed OHB‐1, OHB‐2, OHB‐3, and OHB‐4 with various number average molecular weights (Mn) of 4000, 7400, 14,000, and 83,000, respectively, were blended with PLA. The lower cold‐crystallization temperature (Tcc) and higher heat of cold crystallization (ΔHcc) for blend of PLA/OHB‐1 suggested that thermally‐degraded OHB‐1 formed suitable crystal size during the cooling process and then acted as nucleation agents for PLA in the subsequent heating process. On the other hand, for the blending systems of PLA/dendrimers of hydroxyalkanoic acids, no obvious change on the thermal properties was observed compared with pure PLA except an improved PLA thermal stability possibly resulted from the crosslinking effects of the dendrimers © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Dielectric properties of exfoliated graphite reinforced flouroelastomer composites
Authors: Xu Deng , Sridhar V. , Mahapatra S. P. , Kim Jin Kuk 
Published: October 2008

AbstractDielectric relaxation behavior of nano graphite reinforced flouroelastomer composites has been studied as a function of variation in filler in the frequency range of 0.01–105Hz. The effect of variation in filler loadings on the complex and real parts of impedance was distinctly visible which has been explained on the basis of interfacial polarization of fillers in a heterogeneous medium and relaxation dynamics of polymer chains in the vicinity of fillers. The electric modulus formalism has been utilized to further investigate the conductivity and relaxation phenomenon. The frequency dependence of AC conductivity has been investigated by using Percolation theory. The phenomenon of percolation in the composites has been discussed based on the measured changes in electric conductivity and morphology of composites at different concentrations of the filler. The percolation threshold as studied by DC conductivity occurred in the vicinity of 2.5–3.5 phr of filler loading. Scanning electron microscope microphotographs showed agglomeration of the filler above this concentration and formation of a continuous network structure. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Photocrosslinkable phosphorus containing homo‐ and copolyesters: Synthesis, characterization, and photosensitive properties
Authors: Kaniappan K. , Murugavel S. C. 
Published: October 2008

AbstractA new series of homo‐ and copolyphosphoramide esters containing pendant chlorine group was synthesized from dihydroxy chalcones, N‐(4‐chlorophenyl)phosphoramidic dichloride, and terephthaloyl chloride by interfacial polycondensation technique. The diol monomers were prepared by condensing 4‐hydroxy benzaldehyde and 3‐methoxy‐4‐hydroxybenzaldehyde with 4‐hydroxy acetophenone. The synthesized monomers and polymers were characterized by UV, IR and 1H, 13C, and 31PNMR spectroscopic techniques. Molecular weight of the polymers was determined by gel permeation chromatography. The thermal properties of the polymers were studied by thermogravimetric analysis and differential scanning calorimetry under nitrogen atmosphere. The photo‐crosslinking ability of the polymers in various solvents was observed with UV spectrophotometer. The photocrosslinking proceeds via 2π +2π cycloaddition reaction of α, β‐unsaturated carbonyl group. The comparison study on the rate of photocrosslinking of homo and copolymers was also carried out. The chemical and physical properties of these polyesters are compared with those of the unsubstituted polyesters and the results are discussed herein. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Study of the effect of PEG length in Uni‐HEUR thickener behavior
Authors: Barmar Mohammad 
Published: October 2008

AbstractFour new models of Uni‐HEUR associative thickener were designed and synthesized using various molecular weights of poly(ethylene glycol) (PEG) as hydrophilic segments. The PEG chain ends were capped with octadecyl isocyanate as hydrophobic segments. The structure of the prepared Uni‐HEUR thickeners was confirmed by infrared spectroscopy. The steady shear viscosity measurements of aqueous solution of HEUR models showed that the relative size of hydrophilic segments to hydrophobic segments is very important. Oscillatory measurements confirmed the steady shear viscosity results. It is found, there is an optimum relative size of hydrophilic segments to hydrophobic segments to achieve the thickener with a good performance. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Glucocorticoid‐induced bone loss in mice can be reversed by the actions of parathyroid hormone and risedronate on different pathways for bone formation and mineralization
Authors: Yao Wei , Cheng Zhiqiang , Pham Aaron , Busse Cheryl , Zimmermann Elizabeth A. , Ritchie Robert O. , Lane Nancy E. 
Published: October 2008

AbstractObjectiveGlucocorticoid excess decreases bone mineralization and microarchitecture and leads to reduced bone strength. Both anabolic (parathyroid hormone [PTH]) and antiresorptive agents are used to prevent and treat glucocorticoid‐induced bone loss, yet these bone‐active agents alter bone turnover by very different mechanisms. This study was undertaken to determine how PTH and risedronate alter bone quality following glucocorticoid excess.MethodsFive‐month‐old male Swiss‐Webster mice were treated with the glucocorticoid prednisolone (5 mg/kg in a 60‐day slow‐release pellet) or placebo. From day 28 to day 56, 2 groups of glucocorticoid‐treated animals received either PTH (5 μg/kg) or risedronate (5 μg/kg) 5 times per week. Bone quality and quantity were measured using x‐ray tomography for the degree of bone mineralization, microfocal computed tomography for bone microarchitecture, compression testing for trabecular bone strength, and biochemistry and histomorphometry for bone turnover. In addition, real‐time polymerase chain reaction (PCR) and immunohistochemistry were performed to monitor the expression of several key genes regulating Wnt signaling (bone formation) and mineralization.ResultsCompared with placebo, glucocorticoid treatment decreased trabecular bone volume (bone volume/total volume [BV/TV]) and serum osteocalcin, but increased serum CTX and osteoclast surface, with a peak at day 28. Glucocorticoids plus PTH increased BV/TV, and glucocorticoids plus risedronate restored BV/TV to placebo levels after 28 days. The average degree of bone mineralization was decreased after glucocorticoid treatment (−27%), but was restored to placebo levels after treatment with glucocorticoids plus risedronate or glucocorticoids plus PTH. On day 56, RT‐PCR revealed that expression of genes that inhibit bone mineralization (Dmp1 and Phex) was increased by continuous exposure to glucocorticoids and glucocorticoids plus PTH and decreased by glucocorticoids plus risedronate, compared with placebo. Wnt signaling antagonists Dkk‐1, Sost, and Wif1 were up‐regulated by glucocorticoid treatment but down‐regulated after glucocorticoid plus PTH treatment. Immunohistochemistry of bone sections showed that glucocorticoids increased N‐terminal Dmp‐1 staining while PTH treatment increased both N‐ and C‐terminal Dmp‐1 staining around osteocytes.ConclusionOur findings indicate that both PTH and risedronate improve bone mass, degree of bone mineralization, and bone strength in glucocorticoid‐treated mice, and that PTH increases bone formation while risedronate reverses the deterioration of bone mineralization.
Noninvasive imaging of macrophages in rheumatoid synovitis using 11C‐(R)‐PK11195 and positron emission tomography
Authors: van der Laken Conny J. , Elzinga Ernst H. , Kropholler Mark A. , Molthoff Carla F. M. , van der Heijden Joost W. , Maruyama Kaoru , Boellaard Ronald , Dijkmans Ben A. C. , Lammertsma Adriaan A. , Voskuyl Alexandre E. 
Published: October 2008

AbstractObjectiveNoninvasive imaging by positron emission tomography (PET) of macrophages in inflamed joints of patients with rheumatoid arthritis (RA) may allow early detection of disease activity. We undertook this study to investigate whether rheumatoid synovitis can be visualized by PET using the tracer 11C‐(R)‐PK11195, which binds to peripheral benzodiazepine receptors (PBRs) on macrophages.MethodsKnee joints of 11 RA patients with active arthritis of at least 1 knee joint were imaged with 11C‐(R)‐PK11195 PET. Tissue uptake of 11C‐(R)‐PK11195 was quantified. PET was followed by arthroscopy of the most inflamed knee joint of each RA patient. Synovial tissue samples were subjected to immunohistochemical staining.Results11C‐(R)‐PK11195 uptake on the PET scans was significantly higher in severely inflamed joints than in joints with moderate or mild signs of inflammation. In addition, tracer uptake in contralateral uninflamed knee joints of RA patients was significantly higher than in uninflamed joints of control patients without inflammatory joint disease, suggesting the presence of subclinical disease activity. PET tracer uptake in joints correlated significantly with PBR staining in the sublining of synovial tissue. PBR staining correlated significantly with CD68 staining of macrophages.Conclusion11C‐(R)‐PK11195 PET imaging allows noninvasive in vivo imaging of macrophages in rheumatoid synovitis and possibly even in subclinical synovitis. Noninvasive visualization of macrophages may be useful both for detecting early synovitis and for monitoring synovitis activity during treatment.
The molecular signature of oxidative metabolism and the mode of macrophage activation determine the shift from acute to chronic disease in experimental arthritis: Critical role of interleukin‐12p40
Authors: Takahashi Nozomi , de Jager Victor C. L. , Glück Anton , Letzkus Martin , Hartmann Nicole , Staedtler Frank , Ribeiro‐Dias Fatima , Heuvelmans‐Jacobs Marleen , van den Berg Wim B. , Joosten Leo A. B. 
Published: October 2008

AbstractObjectiveRepeated injection of streptococcal cell wall (SCW) fragments results in chronic arthritis in mice. The objective of this study was to identify genes and pathways that determine disease progression based on gene expression profiling in this model.MethodsChronic arthritis was induced in mice by 4 injections of SCW fragments. RNA samples were isolated from synovial tissue obtained at various time points and were analyzed using mouse genome array and quantitative reverse transcription–polymerase chain reaction techniques. The functional role of potential key genes was evaluated in mice with specific gene deletions.ResultsGene expression analyses revealed a shift in molecular signature. In contrast to an up‐regulation of the inflammatory response pathway, the pathways involved in oxidative metabolism were significantly down‐regulated during the chronic phase of arthritis. Since oxidative metabolism determines the mode of macrophage activation, we investigated phenotype switching in macrophages. Markers of alternatively activated macrophages, such as arginase 1, were at maximal levels during acute inflammation. In contrast, induction of markers of classically activated macrophages (M1), such as interleukin‐1β (IL‐1β) and inducible nitric oxide synthase (iNOS), was relatively low during the acute phase of disease, but highly increased toward the chronic phase. M1 polarization during the chronic phase was accompanied by a Th1 signature, characterized by IL‐12p40, IL‐12p35, and interferon‐γ. However, the absence of IL‐12p40, but not IL‐12p35, significantly inhibited the chronic phase of arthritis and was marked by a reduction in IL‐17 and iNOS levels, as well as restored expression of oxidative metabolism genes.ConclusionM1 polarization accompanied by a decline in oxidative metabolism determine the chronic phase of arthritis. IL‐12p40, most likely acting through the IL‐23/IL‐17 axis, plays a critical role in this process.
Illness perceptions in patients with fibromyalgia and their relationship to quality of life and catastrophizing
Authors: van Wilgen C. Paul , van Ittersum Miriam W. , Kaptein Ad A. , van Wijhe Marten 
Published: October 2008

AbstractObjectiveIn the last decade, illness perceptions have been identified as important in the treatment of fibromyalgia (FM). The aim of the present study was to examine illness perceptions and use of the revised Illness Perception Questionnaire in patients with FM (IPQ‐R‐FM) and their relationship to quality of life and catastrophizing.MethodsA domain with specific causal attributions related to FM was added to the IPQ‐R‐FM. The psychometric properties of the IPQ‐R‐FM dimensions and attribution scales were examined. The causal domain, in which patients describe the most important perceived causes for their FM, was analyzed. To analyze the relationship with quality of life and catastrophizing, the Fibromyalgia Impact Questionnaire and the Pain Catastrophizing Scale were used.ResultsFifty‐one outpatients completed the questionnaires on 2 occasions, 3 weeks apart. FM was considered to be chronic and to have serious consequences; patients perceived little personal control and did not expect medical treatment to be effective. The psychometric properties of the IPQ‐R‐FM were found to be adequate. Patients most frequently attributed the causes of FM to an external somatic source (58%). Quality of life was related to experiencing more consequences attributable to FM. Catastrophizing was related to a limited understanding of the symptoms of FM, the more cyclical nature of FM, and an emotional representation.ConclusionThe IPQ‐R‐FM is a useful tool to assess illness perceptions in patients with FM. Illness perceptions are related to quality of life and catastrophizing; therefore, it seems important to assess and integrate illness perceptions into the management of patients with FM.
Reliability and validity of the myositis disease activity assessment tool
Authors: Sultan Shabina M. , Allen Elizabeth , Oddis Chester V. , Kiely Patrick , Cooper Robert G. , Lundberg Ingrid E. , Vencovsky Jiri , Isenberg David A. 
Published: October 2008

AbstractObjectiveTo test the interrater reliability and validity of the Myositis Disease Activity Assessment Tool, which consists of the Myositis Intention‐to‐Treat Activity Index and the Myositis Disease Activity Assessment Visual Analog Scales.MethodsTwo phases of the study were conducted to assess the reliability and validity of the tool, which was modified following the first phase. In the first phase of the reliability study, 123 adult myositis patients were evaluated in 7 centers, and in the second phase 40 patients were evaluated in 2 centers. The validity study included 294 patients in 5 centers in the first phase and 65 patients in 3 centers in the second phase. The interrater reliability was assessed using intraclass correlation coefficients. The criterion validity was calculated using sensitivity, specificity, and positive predictive value (PPV) of a grade of A in any system. Spearman's rank correlation coefficient was used to measure the convergent validity of cross‐sectional scores between the 2 instruments.ResultsThere was a 2:1 ratio of female to male patients. There was no significant difference in mean age at diagnosis (46.3 versus 46.8 years) and mean disease duration (7.7 versus 10 years) between the 2 groups recruited for the different phases of the study. There was an improvement in interrater reliability in the second phase of the study. There was a significant improvement in the validity of the assessment tool following modification of the tool. The sensitivity, specificity, and PPV of a grade of A in any system improved from 86%, 92%, and 67% in the first phase to 96%, 94%, and 83%, respectively, in the second phase. Convergent validity between the 2 activity tools showed good correlation, ranging from 0.8 to 0.94, for the individual organ systems.ConclusionThis is the first major attempt to assess the reliability and validity of a disease activity index in myositis. Our findings indicate that, following within‐study modification, the tool appears to be a reliable and valid instrument to assess myositis disease activity.
Certolizumab pegol plus methotrexate is significantly more effective than placebo plus methotrexate in active rheumatoid arthritis: Findings of a fifty‐two–week, phase III, multicenter, randomized, double‐blind, placebo‐controlled, parallel‐group study
Authors: Keystone Edward , Heijde Désireé Van Der , Mason David , Landewé Robert , Vollenhoven Ronald Van , Combe Bernard , Emery Paul , Strand Vibeke , Mease Philip , Desai Chintu , Pavelka Karel 
Published: October 2008

AbstractObjectiveTo evaluate the efficacy and safety of 2 dosage regimens of lyophilized certolizumab pegol (a novel PEGylated anti–tumor necrosis factor agent) as adjunctive therapy to methotrexate (MTX) in patients with active rheumatoid arthritis (RA) with an inadequate response to MTX therapy alone.MethodsIn this 52‐week, phase III, multicenter, randomized, double‐blind, placebo‐controlled, parallel‐group trial, 982 patients were randomized 2:2:1 to receive treatment with subcutaneous certolizumab pegol at an initial dosage of 400 mg given at weeks 0, 2, and 4, with a subsequent dosage of 200 mg or 400 mg given every 2 weeks, plus MTX, or placebo plus MTX. Co‐primary end points were the response rate at week 24 according to the American College of Rheumatology 20% criteria for improvement (ACR20) and the mean change from baseline in the modified total Sharp score at week 52.ResultsAt week 24, ACR20 response rates using nonresponder imputation for the certolizumab pegol 200‐mg and 400‐mg groups were 58.8% and 60.8%, respectively, as compared with 13.6% for the placebo group. Differences in ACR20 response rates versus placebo were significant at week 1 and were sustained to week 52 (P < 0.001). At week 52, mean radiographic progression from baseline was reduced in patients treated with certolizumab pegol 200 mg (0.4 Sharp units) or 400 mg (0.2 Sharp units) as compared with that in placebo‐treated patients (2.8 Sharp units) (P < 0.001 by rank analysis). Improvements in all ACR core set of disease activity measures, including physical function, were observed by week 1 with both certolizumab pegol dosage regimens. Most adverse events were mild or moderate.ConclusionTreatment with certolizumab pegol 200 or 400 mg plus MTX resulted in a rapid and sustained reduction in RA signs and symptoms, inhibited the progression of structural joint damage, and improved physical function as compared with placebo plus MTX treatment in RA patients with an incomplete response to MTX.