bluuebunny/crossref_metadata_2025 huggingface dataset:
Miniemulsion polymerization of styrene with polymeric costabilizers
Authors: Chern Chorng‐Shyan , Lin Chi‐Han
Published: March 2004

The polymeric costabilizers poly(stearyl methacrylate‐co‐2‐hydroxyethylmethacrylate) (PSH) and poly(lauryl methacrylate‐co‐2‐hydroxyethylmethacrylate) (PLH), composed of a hydrophilic backbone and several hydrophobic alkyl (stearyl or lauryl) side chains, were prepared by the free‐radical copolymerization of stearyl methacrylate (SMA) or lauryl methacrylate (LMA) with 2‐hydroxyethylmethacrylate and evaluated in the miniemulsion polymerization of styrene (ST). For comparison, the reactive costabilizers SMA and LMA were also included in this work. The hydrophobicity of costabilizers in increasing order was PLH < PSH < LMA < SMA. Only a small amount of these comb‐like copolymers was capable of producing kinetically stable ST emulsion droplets. The more hydrophobic the costabilizer was, the more effective was the costabilizer in the retardation of Ostwald ripening. About 30–40% of the monomer droplets were successfully converted into latex particles during the polymerization. The degree of monomer droplet nucleation increased with increasing hydrophobicity of the costabilizer. The formation of particle nuclei in the continuous aqueous phase played a crucial role in the polymerization kinetics. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 1961–1969, 2004
Synthesis and characterization of polyurethane foam matrices for the support of granular adsorbent materials
Authors: Pinto Moisés L. , Pires João , Carvalho Ana P. , Bordado João C. M. , De Carvalho Manuela B.
Published: March 2004

Polyurethane foams with different formulations were synthesized and characterized for use as supporting matrices of granular solid adsorbents. The open cell content, specific gravity, thermal stability, and hydrophobicity were determined and related to the formulation composition. The synthesized foams had open cell contents of 88.1–98.5% and specific gravity values of 120–28 kg m−3. The thermal stability of the prepared foams was influenced mainly by the water content and the type of isocyanate used. The hydrophobicity was assessed by an analysis of the water adsorption isotherms determined on selected foams, and a correlation between these results and the formulation of the foams was attempted. Two types of activated carbons were supported in a polyurethane matrix. The adsorption characteristics evaluated before and after the supporting procedure, by nitrogen adsorption, revealed that there was only a moderate surface area reduction of 15–20%. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 2045–2053, 2004
Fiber formation and physical properties of chitosan fiber crosslinked by epichlorohydrin in a wet spinning system: The effect of the concentration of the crosslinking agent epichlorohydrin
Authors: Lee Shin‐Hee , Park Soo‐Young , Choi Jae‐Hong
Published: March 2004

The wet spinning of chitosan fibers was studied with 2% acetic acid as the solvent, 10% aqueous sodium hydroxide as the nonsolvent, and a 4% chitosan solution as the polymer. This article describes the crosslinking of the chitosan fibers. Epichlorohydrin (ECH) was selected as a convenient base‐catalyzed crosslinking agent. The coagulation and crosslinking of the chitosan fibers occurred simultaneously in the coagulation bath. In this study, we investigated the effect of the concentration of the crosslinking agent, ECH, in the spinning dope on the structural, thermal, morphological, and mechanical properties (e.g., the tenacity, elongation, and work of rupture) of chitosan fibers. The tenacity of the chitosan fibers, especially the wet tenacity, was improved by crosslinking. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 2054–2062, 2004
The role of additives in the manufacture of sheets of unsaturated polyester and postconsumer unsaturated polyester/glass fiber composites: Mechanical and dynamic mechanical properties
Authors: Pedroso A. G. , Rosa D. S. , Atvars T. D. Z.
Published: March 2004

The storage of postconsumer glass fiber reinforced unsaturated polyester composite impacts negatively on the environment because of the long lifetime and the volume/amount ratio of residuals, which are important aspects to be considered. Two types of additives were employed as an attempt to improve the mechanical properties of sheets manufactured with ground postconsumer glass fiber reinforced orthophthalic unsaturated polyester resin composite and virgin orthophthalic unsaturated polyester resin, a silane‐coupling agent and an organic dispersant. Flexural and impact tests, and dynamic mechanical analyses, demonstrated that the coupling agent increased the mechanical properties, while the dispersant decreased these properties, compared to material without either additive. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 1834–1839, 2004
Synthesis and degradation behavior of poly(propylene carbonate) derived from carbon dioxide and propylene oxide
Authors: Du L. C. , Meng Y. Z. , Wang S. J. , Tjong S. C.
Published: March 2004

High molecular weight and regular molecular structure poly(propylene carbonate) (PPC) was successfully synthesized from carbon dioxide and propylene oxide. The PPC copolymer structure was an exact alternating copolymer as evidenced by the 13C‐NMR technique. Degradative behavior of the PPC was conducted by soil burial and buffer solution immersion (pH = 6) tests, respectively. The results showed that the weight loss of soil buried in PPC films increased more slowly than that immersed in the buffer solution after 6‐month exposure. However, the weight loss of sample immersed in the buffer solution increased rapidly during the first 2 months and reached a value of 4.59%. Water sorption measurement also revealed that the PPC membranes immersed in buffer solution were more hydrophilic than those in soil burial tests. The degradation mechanism of PPC membranes was correlated with the sample morphologies, FTIR, and 1H‐NMR spectra. The SEM morphologies were consistent with the weight loss and water sorption measurements. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 1840–1846, 2004
1H‐ and 13C‐NMR analyses of aqueous polyamideamine–epichlorohydrin resin solutions
Authors: Obokata Takao , Isogai Akira
Published: March 2004

More accurate signal assignment for 1H‐ and 13C‐NMR spectra of aqueous solutions of polyamideamine‐epichlorohydrin (PAE) resin and its related compounds was achieved by using distortionless enhancement of polarization transfer (DEPT) and C‐H correlation spectroscopy (COSY) methods. On the basis of the assignment, we developed new methods to determine the content of four‐membered azetidinium ring (AZR) and number‐average degree of polymerization (DPn) of the repeating unit of PAE by using NMR. Degree of introduction of epichlorohydrin into polyamideamine chains at the initial stage was 75–80%, and the resultant AZR content per one repeating unit in the PAE sample prepared in this study was about 72%. DPn of the initial polyamideamine was 32, and this value decreased to about 18 during the PAE preparation process. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 1847–1854, 2004
Friction and wear studies on nylon‐6/SiO2 nanocomposites
Authors: García Monserrat , De Rooij Matthijn , Winnubst Louis , van Zyl Werner E. , Verweij Henk
Published: March 2004

Composites of nanometer‐sized silica (SiO2) filler incorporated in nylon‐6 polymer were prepared by compression molding. Their friction and wear properties were investigated on a pin on disk tribometer by running a flat pin of steel against a composite disc. The morphologies of the composites as well as of the wear track were observed by scanning electron microscopy (SEM). The addition of 2 wt % SiO2 resulted in a friction reduction (μ) from 0.5 to 0.18 when compared with neat nylon‐6. This low silica loading led to a reduction in wear rate by a factor of 140, whereas the influence of higher silica loadings was less pronounced. The smooth morphology obtained after the wear test indicated the negligible contribution to friction of the pin to the nanocomposite. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 1855–1862, 2004
Synthesis and chain extension of nitroxide‐terminated styrene–maleimide copolymers
Authors: Lokaj J. , Krakovský I. , Holler P. , Hanyková L.
Published: March 2004

Thermal radical copolymerization of styrene (S) and maleimide (MI) at 125°C in diglyme in the presence of 2,2,6,6‐tetramethylpiperidin‐1‐yloxyl radical (TEMPO) was studied. Mole fractions of maleimide in the feed, FMI, varied in the range 0.1–0.9. A quasiliving reaction process proceeded yielding copolymers with a low polydispersity (Mw/Mn = 1.17–1.41). The found azeotropic composition, (FMI)A = 0.46, did not differ substantially from that (0.5) in the conventional radical S‐MI copolymerization. At a higher conversion or MI content in the feed, deactivation of the copolymer chains occurred. The obtained TEMPO‐terminated S‐MI copolymers readily initiated polymerization of styrene; chain extension of the macroinitiators took place, giving poly(S‐co‐MI)‐block‐poly(S) diblock copolymers. The synthesized copolymers containing S and MI units were characterized by elemental analysis, NMR spectroscopy, size‐exclusion chromatography, and differential scanning calorimetry. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 1863–1868, 2004
Properties of a few aromatic poly(thioether ketones) as sulfur‐containing high‐performance polymers
Authors: Matsumura Sumiko , Kihara Nobuhiro , Takata Toshikazu
Published: March 2004

Several basic physical properties of poly(thioether ketones) (PTEKs) were studied in comparison with corresponding ether analogs, poly(ether ketones) (PEKs), and various typical engineering plastics. The water absorption of PTEK (0.13%) was lower than that of the corresponding PEK (0.16%), probably because of the hydrophobic nature of the sulfide group. The dielectric breakdown strengths of PTEK and PEK were much greater than that of commercially available polymers. PTEK had higher dielectric breakdown strength than PEK. Although the volume resistivity of PEK considerably decreased after water absorption, that of PTEK remained high even after water absorption. PTEK exhibited a remarkably high refractive index (nD23 1.66). α‐Transition corresponding to Tg was observed at a high temperature (PTEK‐1, 235°C; PTEK‐2, 269°C) in the dynamic mechanical analysis. Young's modulus and tensile strength of PTEK were comparable to those of commercial high‐performance polymers. PTEK also exhibited excellent flame resistance. Although the linear thermal expansion coefficient of PTEK was greater than that of PEEK, it was still within a practically acceptable level. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 1869–1874, 2004
Modeling of polyurethane foam formation
Authors: Tesser R. , Di Serio M. , Sclafani A. , Santacesaria E.
Published: March 2004

Polymeric foams are widely used both as structural and as thermal insulating material. Few detailed data about the process of foam growth are reported in the literature, especially for recently developed polyurethane formulations that involve the use of a volatile organic compound instead of the banned chlorofluorocarbons (CFCs). In this work, a dedicated device was realized that allows experimental data collection for polymeric foams growth in terms of temperature and density profiles. For modeling and simulation purposes, a model reported in the literature was modified by improving, in particular, the description of the vapor–liquid phase equilibrium for the system blowing agent/polymer mixture. Simulation of the collected experimental data was performed by this model after the determination of the kinetic parameters for the occurring reaction between polyol and isocyanate. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 1875–1886, 2004
Comparison between titanium tetrabutoxide and a new commercial titanium dioxide based catalyst used for the synthesis of poly(ethylene terephthalate)
Authors: Finelli Lara , Lorenzetti Cesare , Messori Massimo , Sisti Laura , Vannini Micaela
Published: March 2004

Titanium‐based catalysts for poly(alkylene terephthalate) synthesis have been known for many years. Up to now, organotitanate compounds are used as catalysts on an industrial scale only for the synthesis of poly(butylene terephthalate) (PBT), poly(trimethylene terephthalate) (PTT), and related copolyesters; for poly(ethylene terephthalate) (PET), synthesis antimony‐based catalysts are preferred. In fact, in this case, titanium is known to cause undesirable discoloration. In this article, a study of PET synthesis using different concentrations of a new titanium dioxide based catalyst (C‐94), commercially available from Acordis Industrial Fibers GmbH, is carried out and compared with the results obtained with titanium tetrabutoxide (TBT) catalyst in the same experimental conditions. The solid‐state properties and composition of C‐94 was investigated by thermogravimetric analysis (TGA) coupled with mass spectroscopy and by X‐ray powder diffraction (XRD). A characterization of the polymers prepared with C‐94 and TBT is also described. The results have shown that the use of C‐94 leads to more hydrolytically stable polymers, whereas no evidence of difference in the catalytic activity, carboxyl end‐groups concentration, diethylene glycol content, and thermal properties were revealed. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 1887–1892, 2004
Pectin and polyacrylamide composite hydrogels: Effect of pectin on structural and dynamic mechanical properties
Authors: Liu Linshu , Cooke Peter H. , Coffin David R. , Fishman Marshall L. , Hicks Kevin B.
Published: March 2004

Composite hydrogels of pectin and polyacrylamide were synthesized and evaluated by scanning electron microscopy, atomic force microscopy, light microscopy, and dynamic mechanical analysis. The crosslinking polymerization of acrylamide in pectin solution resulted in a composite having a macroporous pectin domain with an interstitial polyacrylamide domain. This composite had improved mechanical properties compared to those of either polymer alone, and it absorbed and retained more water than crosslinked polyacrylamide alone. Furthermore, crosslinking polymerization of acrylamide in an existing pectinate scaffold resulted in a double‐network architecture, where filamentous polyacrylamide networks penetrated through pores of the pectin scaffold. It was found that pectins dictated the features of microstructure in the composites through regulating the coordination of phase separation of the two components and water partition between the two phases. Results from this study highlight potential new uses of pectins in protecting the physical structure of environmentally sensitive polymers from mechanical damage related to freezing, lyophilization, and other conditions experienced during their use in biomedical and industrial products. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 1893–1901, 2004
Synthesis and characterization of statistical copolymers of styrene and 4‐(1‐hydroxyalkyl)styrene
Authors: Nasrullah J. Mohammed , Dhamodharan R.
Published: March 2004

A family of new polymers based on poly(4‐(1‐hydroxyalkyl)styrene), and its copolymers with styrene were synthesized and thoroughly characterized by 1H‐NMR, 13C‐NMR, FTIR, and UV spectroscopies. The chemical modification reactions of polystyrene (PS) was used as a novel method of performing the synthesis of poly(4‐(1‐hydroxyethyl‐co‐styrene)), poly(4‐(1‐hydroxypropyl‐co‐styrene)), poly(4‐(1‐hydroxybutyl‐co‐styrene)), and poly(4‐(1‐hydroxyphenylmethyl‐co‐styrene)). The novelty of this method lies in the incorporation of the desired mol % of the functional groups in polystyrene chain, to obtain random copolymers of desired composition. In preliminary testing/evaluation studies the utility and versatility of the new copolymers, which have the potential to be negative‐tone photoresist materials, were studied. Thus a few photoresist formulations based on poly(styrene‐co‐4‐(1‐hydroxyalkylstyrene)) were developed with 5 wt % of a photoacid generator. These studies suggested that the new copolymers synthesized by a simple and alternate method could have the same potential as a photoresist material when compared with the polymers synthesized by the polymerization of the corresponding functional monomer. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 1902–1914, 2004
Effect of degree of polymerization on gelation and flow processability of poly(vinyl chloride)
Authors: Fujiyama Mitsuyoshi , Kondou Manabu
Published: March 2004

The effect of degree of polymerization (DP) on the gelation and flow processability of poly(vinyl chloride) (PVC) was studied. Sheets with adjusted degree of gelation were prepared by rolling rigid pipe formulation suspension PVC compounds with DPs of 800, 1050 and 1300 by changing the milling temperature. Their degrees of gelation were measured with DSC and their capillary flow properties were measured with a capillary rheometer at 150, 170 and 190°C and the effect of DP on the relation between gelation and flow processabilities was studied. Because of the higher shearing heat during milling, the sample with the higher DP had a higher history temperature and thus tended to show a higher degree of gelation. The viscosity increased as the gelation increased. The dependency of viscosity on DP was higher at higher milling and extrusion temperatures and thus at a higher degree of gelation and a lower shear rate. This was assumed to be attributed to the more prominent uniform molecular flow as against the particle flow. The die swell increased with increasing the milling and extrusion temperatures and hence with increasing the gelation. A sample with a lower DP tended to show a larger die swell and this tendency was even more pronounced at the higher extrusion temperature. The melt fracture easily occurred when a sample with advanced gelation was extruded at low temperature. Whereas at low milling temperatures a sample with the lower DP showed a lower critical shear rate at onset of melt fracture, and thus easily generating melt fracture, at high milling temperatures it showed a higher critical shear rate and hence scarcely generated melt fracture. These experimental results were explained by the fact and concept that a sample with a lower DP shows a higher increase in the gelation during extrusion and/or the slighter feature of particle flow as against the uniform molecular flow at the same gelation level. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 1915–1938, 2004
Synthesis and characterization of polyacrylamidegrafted sodium alginate membranes for pervaporation separation of water + isopropanol mixtures
Authors: Toti Udaya S. , Aminabhavi Tejraj M.
Published: March 2004

Polyacrylamide‐grafted‐sodium alginate copolymers were prepared by persulfate‐induced radical polymerization by using polymer‐to‐monomer ratios of 2 : 1 and 1 : 1. Polymers were characterized by Fourier transform infrared spectroscopy, differential thermal analysis, and viscosity. Membranes were prepared from the polymers, crosslinked with glutaraldehyde, and used in the pervaporation separation of water + isopropanol mixtures at 30°C. Equilibrium swelling experiments were performed for mixtures containing 10 to 80 mass % of water in the feed. Both the grafted copolymer membranes were ruptured while separating 10 mass % of water in the feed mixture. However, beyond 20 mass % of water in the feed mixture, flux increased with increasing grafting ratio, while selectivity decreased. Pervaporation separation experiments were carried out at 30, 40, and 50°C for 20 mass % of water in the feed mixture. By increasing the temperature, flux increased, whereas selectivity decreased. Arrhenius activation parameters for pervaporation and diffusion decreased with increasing grafting ratio of the membranes. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 2030–2037, 2004
Effect of molecular weight on brittle‐to‐ductile transition temperature of polyetherimide
Authors: Sanner Mark A. , Haralur Gurulingamurthy , May Andy
Published: March 2004

The fracture and yield strength of polyetherimide was evaluated over a temperature range of 23 to 140°C for materials with number‐average (Mn) and weight‐average molecular weight (Mw) ranging from 15.6 to 22.8 and 36.6 to 52.3 kg/mol, respectively. The brittle‐to‐ductile transition temperature, where an equal probability exists that an impact will result in a brittle or ductile failure, was determined by evaluating the temperature at which fracture and yield strength are equal. The transition temperature decreased from 155 to 60°C with increasing molecular weight and provided a measure of relative ductility between material samples. As a case study, the practical impact strength of an injection‐molded food service tray was determined at 20°C and correlated with fracture strength as a function of molecular weight. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 1666–1671, 2004
Electrochemical polymerization of β‐naphthalene sulfonic acid
Authors: Li Enhua , Huang Zhimin , Shi Gaoquan , Qu Liangti , Zhang Jiaxin
Published: March 2004

β‐Naphthalene sulfonic acid (β‐NSA) has been electrochemically polymerized in a mixed electrolyte of boron trifluoride diethyl etherate (BFEE) solution mixed with a certain amount of trifluoroacetic acid (TFA) or concentrated sulfuric acid (SA). The poly(β‐naphthalene sulfonic acid) (PNSA) film prepared from the medium of BFEE+TFA was partly soluble in methanol. On the other hand, the polymer obtained from the system of BFEE+SA was soluble in water and general polar organic solvents such as methanol, alcohol, and acetone. The structure of PNSA was examined by infrared and UV spectra. Fluorescent spectral studies indicate that the polymer is a blue light emitter with fluorescence quantum efficiency of ∼ 4%. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 1939–1944, 2004
Gas phase polymerization of 1,3‐butadiene with supported neodymium‐based catalyst: Investigation of molecular weight
Authors: Ni Xufeng , Li Junfei , Zhang Yifeng , Shen Zhiquan
Published: March 2004

The gas phase polymerization of 1,3‐butadiene (Bd), with supported catalyst Nd(naph)3/Al2Et3Cl3/Al(i‐Bu)3 or/and Al(i‐Bu)2H, was investigated. The polymerization of Bd with neodymium‐based catalysts yielded cis‐1,4 (97.2–98.9%) polybutadiene with controllable molecular weight (MW varying from 40 to 80 × 104 g mol−1). The effects of reaction temperature, reaction time, Nd(naph)3/Al(i‐Bu)3 molar ratio, and cocatalyst component on the catalytic activity and molecular weight of polymers were examined. It was found that there are two kinds of active sites in the catalyst system, which mainly influenced the MW and molecular weight distribution of polybutadiene. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 1945–1949, 2004
Preparation and performance of aluminum borate whisker–reinforced epoxy composites. I. Effect of whiskers on processing, reactivity, and mechanical properties
Authors: Liang Guozheng , Hu Xiaolan
Published: March 2004

Aluminum borate (Al18B4O33) whisker–reinforced composites based on a epoxy resin, which was made up of a trifunctional epoxy resin, TDE 85, and methyl nadic anhydride (MNA), were prepared, and the effects of the whiskers on the processing, reactivity, and typical mechanical properties of the composites were investigated. Two coupling agents, aluminate (DL411A) and borate (BE4), were used to surface treat the whiskers. Results show that the addition of the whiskers does not change the reactivity of the matrix, while increasing the viscosity of the resin, but when the whisker content is less than 5 wt %, the increased viscosity does not obviously influence the processing characteristics of the resin. Mechanical properties are greatly dependent on the chemistry and concentration of the coupling agent for treating the whiskers. A good coupling agent, which has good interaction with the whiskers and the matrix, can effectively improve the compatibility between the whiskers and the matrix, and thus result in great improvement of mechanical properties. BE4 proved to be better than DL411A for treating the whiskers. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 1950–1954, 2004
Polymerization kinetics and thermal properties of dicyanate/clay nanocomposites
Authors: Kim Dae Su , Lee Kyung Min
Published: March 2004

The polymerization kinetics and thermal properties of dicyanate/clay nanocomposites were investigated. A type of organically modified clay was used as nanometer‐size fillers for the thermosetting dicyanate resin. Differential scanning calorimetry (DSC) was used to study the curing behavior of the dicyanate/clay nanocomposite systems. The polymerization rate of the nanocomposite systems increased with increasing clay content. An autocatalytic reaction mechanism could adequately describe the polymerization kinetics of the dicyanate/clay nanocomposite systems. The polymerization kinetic parameters were determined by fitting the DSC conversion data to the proposed kinetic equation. The glass‐transition temperature of the dicyanate/clay nanocomposites increased with increasing clay content. The thermal decomposition behavior of the dicyanate/clay nanocomposites was investigated by thermogravimetric analysis. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 1955–1960, 2004
Bacillus thuringiensis δ‐endotoxin binding to brush border membrane vesicles of rice stem borers
Authors: Alcantara Edwin P. , Aguda Remedios M. , Curtiss April , Dean Donald H. , Cohen Michael B.
Published: March 2004

The receptor binding step in the molecular mode of action of five δ‐endotoxins (Cry1Ab, Cry1Ac, Cry1C, Cry2A, and Cry9C) from Bacillus thuringiensis was examined to find toxins with different receptor sites in the midgut of the striped stem borer (SSB) Chilo suppressalis (Walker) and yellow stem borer (YSB) Scirpophaga incertulas (Walker) (Lepidoptera: Pyralidae). Homologous competition assays were used to estimate binding affinities (Kcom) of 125I‐labelled toxins to brush border membrane vesicles (BBMV). The SSB BBMV affinities in decreasing order was: Cry1Ab = Cry1Ac > Cry9C > Cry2A > Cry1C. In YSB, the order of decreasing affinities was: Cry1Ac > Cry1Ab > Cry9C = Cry2A > Cry1C. The number of binding sites (Bmax) estimated by homologous competition binding among the Cry toxins did not affect toxin binding affinity (Kcom) to both insect midgut BBMVs. Results of the heterologous competition binding assays suggest that Cry1Ab and Cry1Ac compete for the same binding sites in SSB and YSB. Other toxins bind with weak (Cry1C, Cry2A) or no affinity (Cry9C) to Cry1Ab and Cry1Ac binding sites in both species. Cry2A had the lowest toxicity to 10‐day‐old SSB and Cry1Ab and Cry1Ac were the most toxic. Taken together, the results of this study show that Cry1Ab or Cry1Ac could be combined with either Cry1C, Cry2A, or Cry9C for more durable resistance in transgenic rice. Cry1Ab should not be used together with Cry1Ac because a mutation in one receptor site could diminish binding of both toxins. Arch. Insect Biochem. Physiol. 55:169–177, 2004. © 2004 Wiley‐Liss, Inc.
The role of lipoxygenase products on the endocytosis of yolk proteins in insects: Participation of cAMP
Authors: Medeiros M.N. , Mendonça L.H. , Hunter A.L. , Paiva‐Silva G.O. , Mello F.G. , Henze I.P. , Masuda H. , Maya‐Monteiro C.M. , Machado E.A.
Published: March 2004

The participation of eicosanoids and second messengers in the regulation of endocytosis by the ovaries was investigated using the uptake of Rhodnius heme binding protein (RHBP) as an experimental model. The rate of RHBP uptake decreased up to 40% in the presence of BWA4C and NDGA, 5 and 12‐lipoxygenase inhibitors, respectively, suggesting the involvement of lipoxygenase products in endocytosis regulation. Addition of Leukotriene B4 (LTB4; one product of the 5 lipoxygenase pathway) increased in vitro the uptake of RHBP by 30%. The content of cAMP in the Rhodnius' ovaries were monitored after treatment with different eicosanoids and inhibitors of eicosanoids synthesis. The amount of cAMP decreased in the presence of indomethacin (by 50%), while treatment with PGE2 induced an increase of 85% of this messenger in the ovaries. The presence of LTB4 in the medium inhibited in 60% the content of cAMP in the ovaries, while BWA4C induced a 100% increase of this messenger in the ovaries. Addition of 1 μM DBcAMP in the medium resulted in a 30% decrease in the rate of RHBP uptake. Taken together, these data show that cyclooxygenase and lipoxygenase products participate in the control of protein internalization by modulation of cAMP levels. Arch. Insect Biochem. Physiol. 55:178–187, 2004. © 2004 Wiley‐Liss, Inc.
Expression and localization of the Spodoptera frugiperda allatotropin (Spofr‐AT) and allatostatin (Spofr‐AS) genes
Authors: Abdel‐latief Mohatmed , Meyering‐Vos Martina , Hoffmann Klaus H.
Published: March 2004

Manduca sexta allatotropin and allatostatin were the first corpora allata (CA) regulating neuropeptides identified from Lepidoptera. Recently, we cloned the allatotropin (Spofr‐AT) and the allatostatin (Spofr‐AS) genes from the fall armyworm Spodoptera frugiperda. Using one‐step RT‐PCR for semi‐quantification of the gene expression, we now demonstrate that three mRNA isoforms of the Spofr‐AT gene and the Spofr‐AS gene are expressed in brain, digestive tract, and reproductive organs of larvae, pupae, and adults in a time‐ and tissue‐specific manner. Expression rates in the brain and in various parts of the digestive tract prove the dual role of the peptides as brain/gut (neuro)peptides. The functional meaning of ovarian and testes expression of the genes is not yet clear, although myoregulatory properties of the peptides are probable. The tissue‐specific localization of the prohormone expression, as demonstrated by whole mount in situ hybridization, confirms the overall distribution of the prohormones as shown by RT‐PCR and supports the pleiotropic functions of the peptides. Arch. Insect Biochem. Physiol. 55:188–199, 2004. © 2004 Wiley‐Liss, Inc.
Isolation, characterization, and recombinant expression of multiple serpins from the cat flea, Ctenocephalides felis
Authors: Brandt K.S. , Silver G.M. , Becher A.M. , Gaines P.J. , Maddux J.D. , Jarvis E.E. , Wisnewski N.
Published: March 2004

Several clones encoding serine protease inhibitors were isolated from larval and adult flea cDNA expression libraries by immunoscreening and PCR amplification. Each cDNA contained an open reading frame encoding a protein of approximately 45 kDa, which had significant sequence similarity with the serpin family of serine protease inhibitors. The thirteen cDNA clones isolated to date encode serpin proteins, which share a primary structure that includes a nearly identical constant region of about 360 amino acids, followed by a C‐terminal variable region of about 40–60 amino acids. The variable C‐terminal sequences encode most of the reactive site loop (RSL) and are generated by mutually exclusive alternative exon splicing, which may confer unique protease selectivity to each serpin. Utilization of an alternative exon splicing mechanism has been verified by sequence analysis of a flea serpin genomic clone and adjacent genomic sequences. RNA expression patterns of the cloned genes have been examined by Northern blot analysis using variable region‐specific probes. Several putative serpins have been overexpressed using the cDNA clones in Escherichia coli and baculovirus expression systems. Two purified baculovirus‐expressed recombinant proteins have N‐terminal amino acid sequences identical to the respective purified native mature flea serpins indicating that appropriate N‐terminal processing occurred in the virus‐infected insect cells. Arch. Insect Biochem. Physiol. 55:200–214, 2004. © 2004 Wiley‐Liss, Inc.
Family study of fibromyalgia
Authors: Arnold Lesley M. , Hudson James I. , Hess Evelyn V. , Ware Avis E. , Fritz Deborah A. , Auchenbach Megan B. , Starck Linsey O. , Keck Paul E.
Published: March 2004

Objective

To assess for familial aggregation of fibromyalgia (FM) and measures of tenderness and pain, and for familial coaggregation of FM and major mood disorder (major depressive disorder or bipolar disorder).

Methods

Probands meeting the American College of Rheumatology criteria for FM and control probands with rheumatoid arthritis (RA) and no lifetime diagnosis of FM were recruited from consecutive referrals to 2 community‐based rheumatology practices. Probands were ages 40–55 years and had at least 1 first‐degree relative age 18 years or older who was available for interview and examination. All probands and interviewed relatives underwent a dolorimeter tender point examination and a structured clinical interview. Interviewed relatives were asked about first‐degree relatives who were not available for interview, using a structured family interview. Logistic and linear regression models, adjusting for the correlation of observation within families, were applied to study the aggregation and coaggregation effects.

Results

Information was collected for 533 relatives of 78 probands with FM and 272 relatives of 40 probands with RA. FM aggregated strongly in families: the odds ratio (OR) measuring the odds of FM in a relative of a proband with FM versus the odds of FM in a relative of a proband with RA was 8.5 (95% confidence interval [95% CI] 2.8–26, P = 0.0002). The number of tender points was significantly higher, and the total myalgic score was significantly lower in the relatives of probands with FM compared with the relatives of probands with RA. FM coaggregated significantly with major mood disorder: the OR measuring the odds of major mood disorder in a relative of a proband with FM versus the odds of major mood disorder in a relative of a proband with RA was 1.8 (95% CI 1.1–2.9, P = 0.013).

Conclusion

FM and reduced pressure pain thresholds aggregate in families, and FM coaggregates with major mood disorder in families. These findings have important clinical and theoretical implications, including the possibility that genetic factors are involved in the etiology of FM and in pain sensitivity. In addition, mood disorders and FM may share some of these inherited factors.
Increased serum matrix metalloproteinase 9 levels in systemic lupus erythematosus patients with neuropsychiatric manifestations and brain magnetic resonance imaging abnormalities
Authors: Ainiala Hanna , Hietaharju Aki , Dastidar Prasun , Loukkola Jukka , Lehtimäki Terho , Peltola Jukka , Korpela Markku , Heinonen Tomi , Nikkari Seppo T.
Published: March 2004

Objective

To evaluate whether serum matrix metalloproteinase 9 (MMP‐9) levels are associated with neuropsychiatric manifestations, particularly cognitive dysfunction, as evaluated by neuropsychological testing and brain magnetic resonance imaging (MRI) abnormalities in patients with systemic lupus erythematosus (SLE).

Methods

MMP‐9 determinations were made in 44 patients with SLE and 43 healthy controls who underwent a clinical neurologic and neuropsychological investigation in order to identify neuropsychiatric manifestations. Cerebral MRI scans with volumetric estimation of intracranial cerebrospinal fluid spaces, T1‐weighted lesions, and T2‐weighted lesions were performed for all subjects. SLE activity was assessed by the European Consensus Lupus Activity Measure (ECLAM) index, and accumulated neuropsychiatric abnormality was assessed by the Systemic Lupus International Collaborating Clinics (SLICC)/American College of Rheumatology damage index.

Results

No significant difference was found in serum MMP‐9 levels between the overall group of SLE patients and controls. However, SLE patients who had at least 1 neuropsychiatric manifestation (NPSLE patients) had significantly higher serum MMP‐9 concentrations than did SLE patients without neuropsychiatric syndromes (P = 0.009). Among patients with NPSLE, those with cognitive deficits had significantly higher concentrations of serum MMP‐9 than did those with normal cognitive function (P = 0.027). Furthermore, serum MMP‐9 levels had a significant positive correlation with the volumes of T1‐weighted and T2‐weighted lesions in the brain MRI (P = 0.031 and P = 0.015, respectively). The concentration of serum MMP‐9 correlated significantly with the SLICC index but not with the ECLAM index.

Conclusion

Elevated levels of serum MMP‐9 in patients with SLE may reflect neuropsychiatric involvement, particularly cognitive dysfunction. The serum MMP‐9 concentration may be associated with small‐ vessel cerebral vasculopathy and increased risk of cerebral ischemic events in patients with SLE.
Use of multispectral magnetic resonance imaging analysis to quantify erosive changes in the hands of patients with rheumatoid arthritis: Short‐term and long‐term longitudinal studies
Authors: Ostrowitzki Susanne , Rédei János , Lynch John A. , Carano Richard A. D. , Zaim Souhil , Miaux Yves , Genant Harry K.
Published: March 2004

Objective

Magnetic resonance imaging (MRI) has been shown to be more sensitive than radiography for detecting bone erosions in rheumatoid arthritis (RA). Semiquantitative scoring based on visual image assessment has been introduced. However, there is considerable interest in true quantitative measures, particularly in the context of clinical trials designed to show differences between treatment groups. This study was undertaken to investigate the use of a new quantitative approach, multispectral (MS) image analysis, for assessing erosive change.

Methods

T1‐weighted spin‐echo (SE) and fat‐suppressed gradient‐echo (GE) sequences of metacarpophalangeal joints of the dominant hand were acquired at various time points throughout a 2‐year period. MS analysis was applied to all images, resulting in segmentation into a generalized bone and a soft tissue class. Voxel changes from one to the other class identified apparent bone lesion volume change (ΔBLV). MR images were also visually scored for erosions (E score). All analyses were performed separately, on a per‐joint basis, for short‐term and long‐term data sets.

Results

Analysis of variance with adjustment for individual effect revealed similar results in the short‐term and the long‐term studies, using either GE or SE images for visual assessment. Patients with an increase in E score on visual assessment had a significantly higher ΔBLV than those without.

Conclusion

Temporal MS analysis of MRIs can be used to detect and quantify erosive changes in RA. This semiautomated method may be useful for demonstrating differences between treatment groups in clinical trials.
Cigarette smoking and the risk of systemic lupus erythematosus: A meta‐analysis
Authors: Costenbader Karen H. , Kim Daniel J. , Peerzada Jehanna , Lockman Shahin , Nobles‐Knight Dolores , Petri Michelle , Karlson Elizabeth W.
Published: March 2004

Objective

Existing studies present conflicting evidence for the role of cigarette smoking as a risk factor in the development of systemic lupus erythematosus (SLE). We performed an extensive search of the medical literature for all studies examining this relationship, and performed a meta‐analysis to arrive at a more precise estimate of effect.

Methods

We performed a computerized literature search for all studies (in all languages), using Medline and EMBASE (1966 to present) and the Cochrane Collaboration database, and completed hand searches of relevant bibliographies and abstracts of conference proceedings. Several investigators systematically extracted data from the relevant studies. Unpublished data were obtained from the author of one abstract. Studies were examined in aggregate for heterogeneity and publication bias. The relationships of current smoking and past smoking (prior to the onset of SLE) to development of SLE were analyzed separately.

Results

Fifty‐two studies were identified and chosen for detailed review. Of these, 9 (7 case–control and 2 cohort studies) were appropriate for inclusion in our meta‐analyses. For current smokers compared with nonsmokers, the odds ratio (OR) for development of SLE was significantly elevated (OR 1.50, 95% confidence interval [95% CI] 1.09–2.08). Former smokers, compared with nonsmokers, did not demonstrate an increased risk of SLE (OR 0.98, 95% CI 0.75–1.27). Several subgroups were also analyzed.

Conclusion

Our meta‐analysis of the 7 existing case–control and 2 cohort studies revealed a small but statistically significant association between current smoking and development of SLE. However, no association between past smoking and development of SLE was observed.
Sjögren's syndrome associated with systemic lupus erythematosus: Clinical and laboratory profiles and comparison with primary Sjögren's syndrome
Authors: Manoussakis Menelaos N. , Georgopoulou Chryssoula , Zintzaras Elias , Spyropoulou Marilyn , Stavropoulou Aikaterini , Skopouli Fotini N. , Moutsopoulos Haralampos M.
Published: March 2004

Objective.

To address the clinical, serologic, pathologic, and immunogenetic features of sicca syndrome that occurs in systemic lupus erythematosus (SLE), as well as its similarities to, and differences from, sicca syndrome that occurs in primary Sjögren's syndrome (SS).

Methods.

A cohort of 283 consecutive unselected SLE patients was evaluated for the presence of associated SS using the American–European classification criteria. Clinical and laboratory parameters in SLE patients with SS (SLE–SS) were compared with those in SLE patients without SS (SLE–no SS) and with a group of 86 unselected patients with primary SS.

Results.

SS was identified in 26 SLE patients (9.2%); the SS preceded the development of lupus in 18 of them (69.2%). Compared with the SLE–no SS group, patients with SLE–SS were significantly older, had a higher frequency of Raynaud's phenomenon, anti‐Ro/SSA, anti‐La/SSB, and rheumatoid factor, but had a significantly lower frequency of renal involvement, lymphadenopathy, and thrombocytopenia. Compared with the primary SS group, SLE–SS patients displayed a clinically similar sicca syndrome, but were significantly younger and had an increased frequency of perivascular infiltrates in the salivary glands associated with anticardiolipin antibodies in the serum. SLE–SS patients had a high frequency of the DRB1*0301 allele. This HLA profile distinguished the SLE–SS group from the SLE–no SS group, who had an increased frequency of DRB1*1501 and DQB1*0602 alleles, but was similar to the HLA profile of the primary SS group, who had an increased frequency of DRB1*0301.

Conclusion.

SLE–SS appears to constitute a subgroup of patients with distinct clinical, serologic, pathologic, and immunogenetic features, in whom SS is expressed as an overlapping entity and is largely similar to primary SS.
Is α‐actinin a target for pathogenic anti‐DNA antibodies in lupus nephritis?
Authors: Mason Lesley J. , Ravirajan Chelliah T. , Rahman Anisur , Putterman Chaim , Isenberg David A.
Published: March 2004

Objective

Following recent reports that pathogenic murine anti‐DNA antibodies bind to α‐actinin, it was obviously of interest to assess the ability of human pathogenic anti–double‐stranded DNA (anti‐dsDNA) antibodies to bind this antigen. Both human monoclonal anti‐DNA antibodies and antibodies affinity purified from the sera of patients with systemic lupus erythematosus (SLE) were investigated.

Methods

An enzyme‐linked immunosorbent assay was established to measure immunoglobulin binding to α‐actinin. Antibodies binding dsDNA were purified from the sera of SLE patients who either had active renal disease or had never had renal disease. Serum samples were selected at times when the patients' sera exhibited high IgG binding to dsDNA. The binding of supernatants from 3 high‐affinity human anti‐dsDNA IgG hybridomas (RH14, B3, and DIL‐6) and 7 human IgM anti‐DNA hybridomas was also investigated.

Results

A greater proportion of anti‐dsDNA IgG–binding antibodies purified from patients with renal disease bound to α‐actinin than did those purified from the sera of patients without renal disease. The specificity of binding to the 100‐kd α‐actinin molecule was confirmed by Western blotting. The pathogenic human antibodies RH14 and B3 bound strongly to α‐actinin, while nonpathogenic DIL‐6 bound very weakly. RT84, the IgM antibody that binds dsDNA with the highest affinity, exhibited the greatest binding to α‐actinin.

Conclusion

The results of our study support the findings of previous studies using murine anti‐DNA monoclonal antibodies, which suggest that pathogenic anti‐dsDNA antibodies cross‐react with α‐actinin.
In vivo imaging of experimental arthritis with near‐infrared fluorescence
Authors: Hansch Andreas , Frey Oliver , Sauner Dieter , Hilger Ingrid , Haas Michael , Malich Ansgar , Bräuer Rolf , Kaiser Werner A.
Published: March 2004

Objective

To visualize early experimental arthritis with near‐infrared fluorescence (NIRF) imaging in a murine model of antigen‐induced arthritis (AIA).

Methods

The target of NIRF was the F4/80 antigen present on the surface of macrophages infiltrating the inflamed synovial membrane. Imaging was performed using anti‐F4/80 monoclonal antibodies (mAb) labeled with Cy5.5 fluorochrome. On day 7 of AIA, 6 mice received an intravenous (IV) injection of labeled mAb; control AIA mice (n = 6) received an IV injection of Cy5.5‐labeled isotype control antibody. NIRF imaging was performed before injection (baseline) and until 72 hours thereafter. Histologic evaluation of arthritis severity and immunohistochemical assessment of F4/80 antigen density were also performed on day 7.

Results

NIRF imaging showed an accumulation of fluorochrome probes in the inflamed knee joints and, to a lesser extent, in the contralateral (nonarthritic) knee joints. The signal induced by mAb F4/80 was clearly higher than that generated by the isotype control. Accumulation of fluorochrome probes in the joints was confirmed histologically by confocal laser scanning microscopy.

Conclusion

The use of fluorochromes allows imaging of arthritis in the near‐infrared range. Accumulation in the contralateral, nonarthritic knee joints can be explained by the presence of sentinel macrophages in normal synovium or by a mild contralateral response due to systemic activation or neurogenic mechanisms.
Lack of response to anakinra in rheumatoid arthritis following failure of tumor necrosis factor α blockade
Authors: Buch Maya H. , Bingham Sarah J. , Seto Yohei , McGonagle Dennis , Bejarano Victoria , White Jo , Emery Paul
Published: March 2004

Objective.

In patients with rheumatoid arthritis (RA) treated with tumor necrosis factor α (TNFα)– blocking therapy, there is heterogeneity of response. This raises the possibility that in certain circumstances, cytokines such as interleukin‐1 (IL‐1) may dominate the drive toward joint inflammation. This study was undertaken to investigate whether blocking the action of IL‐1 with an IL‐1 receptor antagonist (IL‐1Ra) is efficacious in patients with disease that did not respond to TNFα blockade.

Methods.

We identified 26 RA patients whose disease had failed to respond to TNFα‐blocking therapy, defined as failure to achieve or sustain a 20% improvement in disease activity according to the criteria of the American College of Rheumatology (ACR20 response). These patients were then treated with anakinra (100 mg/day subcutaneously) for 12 weeks, and their levels of response were assessed.

Results.

After 3 months of anakinra therapy, only 2 of 26 patients (8%) achieved an ACR20 response; none achieved an ACR50 or ACR70 response. A rise in the mean C‐reactive protein level and an increase in the mean swollen joint count were noted during the study period.

Conclusion.

This study demonstrates that patients with disease that fails to respond to TNFα blockade also do not respond to IL‐1Ra. These data do not provide evidence of a dominant role for IL‐1 in patients who do not respond to TNFα blockade, but they do not exclude a role for other proinflammatory mediators.