bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis of oligo‐ortho‐azomethinephenol and its oligomer–metal complexes: Characterization and application as anti‐microbial agents
Authors: Kaya Ismet , Vilayetoğlu Adalet R. , Topak Hasan 
Published: October 2002

AbstractThe oxidative polycondensation reaction conditions and optimum parameters of o‐phenylazomethinephenol (PAP) with oxygen (air) and NaOCl were determined in an aqueous alkaline solution at 60–98°C. The properties of oligo‐o‐phenylazomethinephenol (OPAP) were studied by chemical and spectra analyses. PAP was converted to dimers and trimers (25–60%) by oxidation in an aqueous alkaline medium. The number average molecular weight (Mn), mass average molecular weight (Mw), and polydispersity index (PDI) values were 1180 g mol−1, 1930 g mol−1, and 1.64, respectively. According to these values, 20–33% of PAP turned into OPAP. During the polycondensation reaction, a part of the azomethine (CHN) groups oxidized to carboxylic (COOH) group. Thus, a water‐soluble fraction of OPAP was incorporated in the carboxylic (COOH); (2–20%) group. Also, the structure and properties of oligomer–metal complexes of OPAP with Cu(II), Ni(II), Zn(II), and Co(II) were studied. Antimicrobial activites of the oligomer and its oligomer–metal complexes were tested against B. cereus, L. monocytogenes, B. megaterium, B. subtilis, E. coli, Str. thermophilus, M. smegmatis, B. brevis, E. aeroginesa, P. vulgaris, M. luteus, S. aureus, and B. jeoreseens. Also, according to differential thermal analysis and thermogravimetric analysis, OPAP and its oligomer–metal complexes were stable throughout to temperature and thermo‐oxidative decomposition. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 2004–2013, 2002
High styrene–rubber ionomers, an alternative to thermoplastic elastomers
Authors: Samuel Jacob , Xavier Thommachan , Kurian Thomas 
Published: October 2002

AbstractHigh styrene rubber ionomers were prepared by sulfonating styrene–butadiene rubber of high styrene content (high styrene rubber) in 1,2‐dichloroethane using acetyl sulfate reagent, followed by neutralization of the precursor acids using methanolic zinc acetate. The ionomers were characterized using X‐ray fluorescence spectroscopy, Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance spectroscopy (NMR), dynamic mechanical analysis (DMA), and also by the evaluation of mechanical properties. The FTIR studies of the ionomer reveal that the sulfonate groups are attached to the benzene ring. The NMR spectra give credence to this observation. Results of DMA show an ionic transition (Ti) in addition to glass–rubber transition (Tg). Incorporation of ionic groups results in improved mechanical properties as well as retention of properties after three cycles of processing. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 2294–2300, 2002
Synthesis and characterization of alternating copolymer from carbon dioxide and propylene oxide
Authors: Wang S. J. , Du L. C. , Zhao X. S. , Meng Y. Z. , Tjong S. C. 
Published: October 2002

AbstractHigh yield and pure zinc glutarate catalysts used for copolymerization of carbon dioxide and propylene oxide have been synthesized in different solvents by ultrasonic methodology. For the purposes of comparison, low‐yield zinc glutarates were also synthesized via mechanical stirring method with other synthetic conditions remaining unchanged. Fourier Transform Infrared Spectroscopy and wide‐angle X‐ray diffraction techniques confirmed the presence of high‐quality zinc glutarate catalysts. Accordingly, poly(propylene carbonate) (PPC) can be synthesized from carbon dioxide and propylene oxide using the zinc glutarate catalysts. It was confirmed that the as‐prepared PPC had an alternating copolymer structure together with high molecular weight. The thermal and mechanical properties of the obtained PPC copolymer were determined by means of differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and tensile test. DSC and TGA results showed that the PPC copolymer exhibited high glass transition temperature (39.39°C) and decomposition temperature (278°C) when compared to their corresponding values reported in the literature. Tensile test showed that the PPC film exhibited superior mechanical strength. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 2327–2334, 2002
Surface modification of PET films by pulsed argon plasma
Authors: Inagaki N. , Tasaka S. , Narushima K. , Kobayashi H. 
Published: October 2002

AbstractThe rf power was modulated (discharge on‐time of 10 μs and discharge off‐time of 50–500 μs), for pulsed argon (Ar) and oxygen (O2) plasmas used to irradiate PET film surfaces to modify the film surfaces. From data regarding the contact angle for the modified PET film surfaces and chemical analyses with XPS, effects of the rf power modulation on the surface modification are discussed. The pulsed Ar and O2 plasmas are effective in modification of the PET film surface. There is no difference in the contact angle between the pulsed plasma and the continuous plasma. Furthermore, the pulsed Ar plasma is advantageous in formation of hydroxyl groups on the PET film surfaces. The rf power modulation has a possibility to modify into peculiar surfaces. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 2845–2852, 2002
A comprehensive investigation of the origins of surface roughness and haze in polyethylene blown films
Authors: Sukhadia Ashish M. , Rohlfing David C. , Johnson Matthew B. , Wilkes Garth L. 
Published: October 2002

AbstractIn an earlier publication we showed that the optical haze properties of blown and cast polyethylene (PE) films were adversely affected (i.e., haze increased) as a result of enhanced surface roughness caused by the formation of distinct optically anisotropic “spherulitic‐like” superstructures. In this report we have found that for a very wide variety of PE blown films, the total haze percent exhibited a complex parabolic relationship with the logarithm of the recoverable shear strain parameter, γ∞. At low values of γ∞, superstructures were developed (as discussed in our previous report) that increased surface roughness and hence total haze. As γ∞ increased, such superstructures were either significantly diminished in size or altogether absent, giving rise instead to an oriented, row‐nucleated, stacked lamella texture that decreased surface roughness and hence total haze. However, at even higher γ∞ values, representing highly melt elastic behavior, fine‐scale surface roughness due to high melt elastic instabilities was induced, thereby increasing surface roughness and consequently total haze as well. It was demonstrated in this work that two PE resins could exhibit the same level of total haze as a consequence of two completely different mechanisms or origins. Furthermore, we believe that this is the first time that both very low and very high melt elasticity have been shown as primary causative factors in yielding high haze in PE blown films, albeit for fundamentally very different reasons. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 2396–2411, 2002
Effects of chemical structure changes on curing reactions and thermal properties of cyanate ester‐cured rigid‐rod epoxy resins
Authors: Su W‐F. A. , Chuang Chih‐Min 
Published: October 2002

AbstractHow chemical structure changes affect the curing reactions and thermal properties of 2,2′‐bis(4‐cyanatophenyl) propane (cyanate ester) cured rigid‐rod epoxy resins has been studied for biphenol and tetramethyl biphenol epoxies. The formation of an oxazolidinone ring is the dominant curing reaction for biphenol epoxy, whereas the formation of a cyanurate ring is the dominant curing reaction for tetramethyl biphenol epoxy, due to the bulky methyl substitutions on the biphenol chain. The crosslinkable cyanurate structure has a higher thermal stability than that of the linear oxazolidinone structure, giving the cyanate ester cured tetramethyl biphenol epoxy resin (molar equivalent) a higher glass transition temperature (260 vs. 218°C) and thermal decomposition temperature (366 vs. 312°C) than that of cyanate ester cured biphenol epoxy resin. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 2419–2422, 2002
Gas diffusion and dielectric studies of polystyrene‐fullerene compositions
Authors: Polotskaya G. A. , Gladchenko S. V. , Zgonnik V. N. 
Published: October 2002

AbstractPolystyrene‐fullerene compositions containing up to 0.45 mol % (3 wt %) fullerene C60 were investigated. It was established that the addition of fullerene to polystyrene (PS) leads to an increase of molecular packing density and so influences the transport of small molecules through the polymer films. Gas diffusion through films of PS‐fullerene compositions is slower than through PS films, and gas separating properties of compositions are higher. Dielectric studies showed that the fullerene is distributed as clusters in the polymer matrix of solid composition prepared from a toluene solution of PS and fullerene. Heating without air to the temperature higher than PS glass transition leads to increasing relaxation time of α‐transition in PS of compositions containing >0.15 mol % (1 wt %) fullerene. This effect is caused by rather strong interaction of PS chains via fullerene molecules entered into the PS‐fullerene complex. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 2946–2951, 2002
Thermogravimetric analysis of methyl methacrylate‐graft‐natural rubber
Authors: Peng Zheng , Li Si‐Dong , Huang Mao‐Fang , Xu Kui , Wang Chen , Li Pu‐Wang , Chen Xiao‐Guang 
Published: October 2002

AbstractThe thermal degradations of methyl methacrylate‐graft‐natural rubber (MG) at different heating rates (B) in nitrogen were studied by thermogravimetric analysis. The results indicate that the thermal degradation of MG in nitrogen is a one‐step reaction. The degradation temperatures increase along with the increment of heating rates. The temperature of initial degradation (T0) is 0.448B + 362.4°C, the temperature at maximum degradation rate, that is, the peak temperature on a differential thermogravimetric curve (Tp) is 0.545B + 380.7°C, and the temperature of final degradation (Tf) is 0.476B + 409.4°C. The degradation rate at Tp is not affected by B, and its average value is 48.9%; the degradation rate at Tf is not affected by B either, and its average value is 99.3%. The reaction order (n) is 2.1 and is not affected by B. The reaction activation energy (E) and the frequency factor (A) increase along with B, and the apparent reaction activation energy (E0) is 254.6 kJ/mol. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 2952–2955, 2002
Suppression of the melanogenic potential of migrating neural crest‐derived cells by the branchial arches
Authors: Jacobs‐Cohen Rae J. , Wade Paul R. , Gershon Michael D. 
Published: October 2002

AbstractThe development of melanocytes from neural crest‐derived precursors that migrate along the dorsolateral pathway has been attributed to the selection of this route by cells that are fate‐restricted to the melanocyte lineage. Alternatively, melanocytes could arise from nonspecified cells that develop in response to signals encountered while these cells migrate, or at their final destinations. In most animals, the bowel, which is colonized by crest‐derived cells that migrate through the caudal branchial arches, contains no melanocytes; however, the enteric microenvironment does not prevent melanocytes from developing from crest‐derived precursors placed experimentally into the bowel wall. To test the hypothesis that the branchial arches remove the melanogenic potential from the crest‐derived population that colonizes the gut, the Silky fowl (in which the viscera are pigmented) was studied. Sources of crest included Silky fowl and quail vagal and truncal neural folds/tubes, which were cultured or explanted to chorioallantoic membranes alone or together with branchial arches or limb buds from Silky fowl, White Leghorn, or quail embryos. Crest and mesenchyme‐derived cells were distinguished by using the quail nuclear marker. Melanocytes developed from Silky fowl and quail crest‐derived cells. Melanocyte development from both sources was inhibited by quail and White Leghorn branchial arches (and limb buds), but melanocyte development was unaffected by branchial arch (and limb buds) from Silky fowl. These observations suggest that a factor(s) that is normally expressed in the branchial arches, and is lacking in animals with the Silky mutation, prevents cells with a melanogenic potential from colonizing the bowel. Anat Rec 268:16–26, 2002. © 2002 Wiley‐Liss, Inc.
Heterogeneity of chondroitin sulfate glycosaminoglycan localization during early development of the striped bass (Morone saxatilis)
Authors: Capehart Anthony A. , Scemama Jean‐Luc , Singhas Charles A. , Cox Sarah 
Published: October 2002

AbstractRecent studies have suggested important functions for proteoglycan‐associated chondroitin sulfate glycosaminoglycans (GAGs) during embryonic and larval development in numerous organisms, including the teleost. Little is known, however, about the specific distribution of different chondroitin sulfate GAGs during early development. The present study utilized immunohistochemistry to localize chondroitin sulfate GAG antigens during development of the striped bass (Morone saxatilis). Immunoreagents utilized were monoclonal antibodies (MAbs) TC2, d1C4, and CS‐56, which recognize, respectively, native epitopes on glycosaminoglycan chains enriched in chondroitin‐4‐, chondroitin‐6‐, and both chondroitin‐4‐ and ‐6‐sulfate. Little or no immunoreactivity was observed in gastrulating embryos at 18 hr postfertilization with any MAb tested. By 24 hr (8 somites), the CS‐56 epitope was localized around the notochord. At hatching (48 hr) and early larval (72 hr) stages, d1C4 and CS‐56 antigens codistributed in some sites (e.g., the notochord and myosepta), but a striking heterogeneity of chondroitin sulfate GAG localization was observed in other developing tissues, including the eye and specific subsets of basement membrane. At these latter time points, TC2 reacted primarily with the extracellular matrix of the developing heart, particularly the ventricular and conotruncal segments. Heterogeneous patterning of these chondroitin sulfate GAG epitopes suggests dynamic regulation of proteoglycan function during critical morphogenetic events in early development of the striped bass. Anat Rec 268:47–58, 2002. © 2002 Wiley‐Liss, Inc.
Satellite remote sensing and archaeology: a comparative study of satellite imagery of the environs of Figsbury Ring, Wiltshire
Authors: Fowler Martin J. F. 
Published: October 2002

AbstractThe abilities of three satellite remote sensed image products (low spatial resolution LANDSAT Thematic Mapper (TM); medium resolution SPOT Panchromatic; high resolution KVR‐1000) to detect archaeological features in the environs of the Iron Age hillfort at Figsbury Ring, Wiltshire, have been evaluated. Given prior knowledge of their locations, relatively large features together and those possessing a strong linear nature could be detected on the LANDSAT TM multispectral and SPOT Panchromatic image products. Near‐infrared TM imagery showed promise for the detection of smaller features as a result of differences in vegetation cover, but was constrained by its low spatial resolution. High resolution Russian KVR‐1000 imagery was found to be capable of detecting both upstanding and ploughed‐out archaeological features without the need for prior knowledge of ground truth.It is concluded that satellite imagery, although not a substitute for conventional aerial photography, represents a complementary source of information when prospecting for archaeological features. In a regional context, low resolution multispectral imagery can be used for the prospection for areas of high archaeological potential through the use of image processing and modelling techniques and, together with medium resolution imagery can be used to prepare base maps of regions for which up to date mapping is not available. High‐resolution imagery, together with conventional aerial photographs, can be used subsequently to detect and map archaeological features. Copyright © 2002 John Wiley & Sons, Ltd.
T cell autoimmunity to histones and nucleosomes is a latent property of the normal immune system
Authors: Andreassen Kristin , Bendiksen Signy , Kjeldsen Elisabeth , Van Ghelue Marijke , Moens Ugo , Arnesen Egil , Rekvig Ole Petter 
Published: October 2002

AbstractObjectiveInvestigators in this study undertook to determine whether in vitro antigen‐responsive immune (polyomavirus T antigen [T‐ag]– specific) and autoimmune (histone‐specific) T cells from normal individuals share structural and genetic characteristics with those from patients with systemic lupus erythematosus (SLE).MethodsHistone‐specific T cells were generated by stimulation of peripheral blood mononuclear cells (PBMCs) with nucleosome–T‐ag complexes and were subsequently maintained by pure histones. T‐ag–specific T cell clones were initiated and maintained by T‐ag. The frequencies of circulating histone‐ and T‐ag–specific T cells were determined in healthy individuals and in SLE patients by limiting dilution of PBMCs. T cell receptor (TCR) gene usage and variable‐region structures were determined by complementary DNA sequencing. These sequences were compared between T‐ag– and histone‐specific T cells and between normal individuals and SLE patients for each specificity.ResultsIndividual in vitro–expanded histone‐ and T‐ag–specific T cells from normal individuals displayed identical TCR Vα and/or Vβ chain third complementarity‐determining region (CDR3) sequences, indicating that they were clonally expanded in vivo. The frequencies of in vitro antigen‐responsive T‐ag– or histone‐specific T cells from normal individuals were similar to those from SLE patients. Although heterogeneous for variable‐region structure and gene usage, histone‐specific T cells from healthy individuals and SLE patients selected aspartic and/or glutamic acids at positions 99 and/or 100 of the Vβ CDR3 sequence.ConclusionAutoimmune T cells from healthy individuals can be activated by nucleosome– T‐ag complexes and maintained by histones in vitro. Such T cells possessed TCR structures similar to those from SLE patients, demonstrating that T cell autoimmunity to nucleosomes may be a latent property of the normal immune system.
Hydroxychloroquine concentration–response relationships in patients with rheumatoid arthritis
Authors: Munster Tino , Gibbs John P. , Shen Danny , Baethge Bruce A. , Botstein Gary R. , Caldwell Jacques , Dietz Fredrick , Ettlinger Robert , Golden Harvey E. , Lindsley Herbert , McLaughlin George E. , Moreland Larry W. , Roberts W. Neal , Rooney Theodore W. , Rothschild Bruce , Sack Marshall , Sebba Anthony I. , Weisman Michael , Welch Kathryn E. , Yocum David , Furst Daniel E. 
Published: October 2002

AbstractObjectiveA dose–response relationship for hydroxychloroquine (HCQ), in terms of the proportion of patients achieving the Paulus 20% criteria for improvement, had previously been observed in patients with rheumatoid arthritis (RA) receiving a 6‐week loading regimen of 400, 800, or 1,200 mg HCQ daily. This present retrospective analysis was performed to investigate possible relationships between the blood HCQ and HCQ‐metabolite concentrations and measures of efficacy and toxicity. In addition, we sought to ascertain whether further investigation of HCQ/HCQ‐metabolite levels might lead to testing of one of these substances as a new antirheumatic drug.MethodsPatients with active RA (n = 212) began a 6‐week, double‐blind trial comparing 3 different doses of HCQ at 400, 800, or 1,200 mg/day, followed by 18 weeks of open‐label HCQ treatment at 400 mg/day. Patients were repeatedly evaluated for treatment efficacy and toxicity. Blood samples were available from 123 patients for analysis of HCQ, desethylhydroxychloroquine (DHCQ), desethylchloroquine (DCQ), and bisdesethylchloroquine (BDCQ) levels using high‐performance liquid chromatography. Achievement of the modified Paulus 20% improvement criteria for response in RA was used as the primary efficacy parameter. Spontaneously reported adverse events were categorized and analyzed as toxicity outcome variables. The relationship between response (efficacy and toxicity) and drug levels was evaluated using logistic regression analysis.ResultsThe subset of patients with blood concentration data was equivalent to the larger study population in all demographic and outcome characteristics. The mean HCQ, DHCQ, and DCQ elimination half‐lives were 123, 161, and 180 hours, respectively. There was a positive correlation between the Paulus 20% improvement criteria response and blood DHCQ concentrations during weeks 1–6 (P < 0.001). A potential relationship between ocular adverse events and BDCQ levels was found (P = 0.036). Logistic regression analysis of adverse events data showed that adverse gastrointestinal events were associated with higher HCQ levels (P = 0.001–0.021) during weeks 1, 2, and 3.ConclusionThere is a weak, but predictable, relationship between blood DHCQ concentrations and efficacy of treatment with HCQ. In addition, there is an association between gastrointestinal adverse events and elevated blood HCQ concentrations. Further investigation of these relationships is warranted to see if DHCQ may be introduced as a new antirheumatic drug.
Necessary role of phosphatidylinositol 3‐kinase in transforming growth factor β–mediated activation of Akt in normal and rheumatoid arthritis synovial fibroblasts
Authors: Kim Giok , Jun Jae‐Bum , Elkon Keith B. 
Published: October 2002

AbstractObjectiveRheumatoid arthritis is a disease that, pathologically, is characterized by the progressive growth and invasion of the synovial pannus into the surrounding cartilage and bone. Many cytokines, including transforming growth factor β1 (TGFβ1), have been implicated in this process, but their mode of action is incompletely understood. The goal of the present study was to better understand the downstream signaling pathways of TGFβ in fibroblasts.MethodsThe role of phosphatidylinositol 3‐kinase (PI 3‐kinase) was determined by chemical inhibition with LY294002 or wortmannin. Activation of protein kinase B (Akt), c‐Jun N‐terminal kinases (JNKs), and extracellular signal–regulated kinases (ERKs) was evaluated by Western blot analysis using phospho‐specific antibodies.ResultsExposure of fibroblasts to TGFβ rapidly induced activation of a kinase, Akt, that is known to inhibit apoptosis by a variety of pathways. Activation of Akt was blocked by the specific PI 3‐kinase inhibitor, LY294002, indicating that TGFβ‐mediated phosphorylation of Akt was dependent on PI 3‐kinase activation. This activation pathway was relatively selective for Akt, since inhibition of PI 3‐kinase failed to substantially modify activation of ERKs or JNKs in synovial fibroblasts. Inhibition of the PI 3‐kinase/Akt pathway resulted in impaired proliferation of synovial fibroblasts and partial attenuation of the protective effect of TGFβ on Fas‐mediated apoptosis.ConclusionTGFβ exerts its growth and antiapoptotic effects on fibroblasts, at least in part, by activation of the PI 3‐kinase/Akt pathway.