bluuebunny/crossref_metadata_2025 huggingface dataset:
Ethylene and 1‐hexene sorption in LLDPE under typical gas‐phase reactor conditions: Experiments
Authors: Novak Antonin , Bobak Marek , Kosek Juraj , Banaszak Brian J. , Lo Dennis , Widya Tomy , Harmon Ray W. , de Pablo Juan J.
Published: January 2006

The sorption of ethylene and 1‐hexene and their mixture in three poly(ethylene‐co‐1‐hexene) samples is measured gravimetrically at temperatures 70, 90, and 150°C and pressures 0–30 bar. Gravimetric sorption measurements are supplemented with microscopic observations of swelling of polyethylene particles caused by sorption and the extent of swelling is found to be significant. Experimental data are compared with predictions of PC‐SAFT (perturbed chain—‐statistical associating fluid theory) equation of state. Comparison of sorption data in semicrystalline polymer (measured at 70 and 90°C) and amorphous polymer (at 150°C) demonstrates the constraining effect of semicrystalline structure. Solubilities of penetrants in investigated samples are not observed to depend on the content of 1‐hexene in copolymers. The solubility of the mixture of ethylene and 1‐hexene is smaller than the sum of solubilities of individual components at 70 and 90°C. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 1124–1136, 2006
Influence of poly(ethylene glycol)‐containing additives on extrusion of ultrahigh molecular weight polyethylene/polypropylene blend
Authors: Xie Meiju , Liu Xiaolong , Li Huilin
Published: January 2006

The influence of poly(ethylene glycol) (PEG)‐containing additives on the extrusion behavior of ultrahigh molecular weight polyethylene/polypropylene (UHMWPE/PP) blend was studied. It was found that the addition of small amounts of PEG to UHMWPE/PP blend resulted in significant reduction of die pressure and melt viscosity, and obvious increase of the flow rate at a given die pressure, while PEG/diatomite binary additives enhanced the improvement in the processability of UHMWPE/PP blend. When pure HDPE was extruded with the die through which UHMWPE/PP/PEG blend was previously extruded, the extrusion pressure of HDPE increased with the extrusion time gradually. This meant that PEG might migrate to the die wall surface and coat it in the extrusion of UHMWPE/PP/PEG blend. FTIR spectra and SEM micrographs of the UHMWPE/PP/PEG extrudates indicated that PEG located not only at the surface but also in the interior of the extrudates. So, the external lubrication at the die wall, combined with the internal lubrication to induce interphase slippage of the blend, was proposed to be responsible for the reduction of die pressure and viscosity. In addition, an ultrahigh molecular weight polysiloxane and a fluoropolymer processing aid were used as processing aids in the extrusion of UHMWPE/PP as control, and the results showed that only minor reduction effects in die pressure and melt viscosity were achieved at their suggested loading level. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 1282–1288, 2006
New dinitroxide for stable free radical polymerization of styrene
Authors: Zhang Zhengbiao , Zhu Xiulin , Zhu Jian , Cheng Zhenping , Lu Jianmei
Published: January 2006

A new dinitroxide (1,4‐di (1‐oxy‐2,2,6,6‐tetramethyl‐1‐piperidin‐4‐yl)‐xylene) (DTPX) was synthesized and successfully used in stable free radical polymerization of styrene. The results of the polymerizations showed that the DTPX was a suitable mediating agent for stable free radical polymerization of styrene. However, it was found that the dinitroxide mediating process resulted in a higher level of decomposition of the internal bisalkoxyamine linkage in the polymer chain, which resulted in polymers possessing a terminal alkoxyamine and an adjacent hydroxylamine, and the decomposition became more obvious at high conversion through monitoring the change of molecular weights with the conversion by gel permeation chromatography and the polymer structure by 1H‐NMR. The reaction temperature showed obvious effects on the polymerization, and the polymerization of styrene at 110°C led to a better controlled polymerization than that at 125°C with narrower molecular weight distributions and slight decomposition of the nitroxide up to monomer conversions of 76.7%, however, the rate of the polymerization was decreased and an induction period appeared at 110°C. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 1137–1145,2006
Morphology and mechanical properties of blends of linear low density polyethylene and poly(ethene‐propene‐1‐butene)
Authors: Quental A. C. , Felisberti M. I.
Published: January 2006

Blends of linear low density polyethylene (LLDPE) and ethene‐propene‐1‐butene copolymer (t‐PP) were obtained through mechanical mixing using a single‐screw extruder with different compositions: 20, 40, 50, 60, and 80 wt % of t‐PP. For this, two types of polyethylene were used: 1‐hexene comonomer and 1‐octene comonomer based. The same blends were prepared in a batch mixer and the torque and temperature were analyzed. The torque showed a decrease with increasing t‐PP content, indicating better processability of the mixture in comparison with LLDPE. The morphology of the blends was analyzed by SEM and showed a composition dependence. The mechanical properties of the blends were evaluated by tensile tests. The results revealed that the best properties were obtained in a 20% t‐PP blend. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 1255–1261, 2006
Intermolecular interactions between bovine serum albumin and certain water‐soluble polymers at various temperatures
Authors: Kavlak Serap , Güner Ali
Published: January 2006

Viscometric behaviors of dextran (Dx), poly(N‐vinyl‐2‐pyrrolidone) (PVP), and poly(ethylene oxide) (PEO) with bovine serum albumin (BSA) in aqueous solutions have been studied at 25, 30, and 35°C. The reduced viscosity and intrinsic viscosity have been experimentally measured for the polymer/water and polymer/BSA/water systems by classical Huggins equation. Measurements of reduced viscosities of the Dx, PVP, and PEO in water have been calculated and all intrinsic viscosities of PEO([η]PEO) are larger than that of Dx([η]Dx), and PVP([η]PVP) in aqueous solutions, at all temperatures. The intrinsic viscosities of PVP, PEO, and Dx were found to be dependent on the concentration of BSA. The presence of BSA (0.05, 0.10, and 0.30 wt %) led to a decrease in the intrinsic viscosities of polymers, at 25, 30, and 35°C. The concentration difference of BSA (Δ[BSA]) is most effective in decreasing the intrinsic viscosities of Dx at 25°C and PEO at 30 and 35°C. In other words, Δ[η] (%) order followed as Dx > PEO > PVP at 25°C and PEO > Dx > PVP at 30 and 35°C. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 1554–1560, 2006
Characteristics of methacrylic acid‐grafted polyethylene films prepared by photografting in the presence of polyfunctional monomers
Authors: Kubota Hitoshi , Kojima Masako , Kuroda Shin‐ichi
Published: January 2006

Photografting of methacrylic acid (MAA) on low‐density polyethylene film (thickness = 30 μm), on which xanthone photoinitiator was coated earlier, in the presence of polyfunctional monomers such as N,N′‐methylenebisacrylamide, ethylene glycol dimethacrylate, and trimethylol propane triacrylate was examined at 60°C in water/acetone (3:1 v/v) mixture solvent. The photografting was retarded at the earlier stage of polymerization, and then accelerated when small amounts of the polyfunctional monomers (1–3 mol % of MAA monomer used) were added to the system. Addition of the polyfunctional monomers did not affect distribution of the grafted chains in the cross section of the resultant MAA‐grafted PE film, which was measured by electron probe microanalysis. The MAA‐grafted samples were subjected to adsorption of cupric ions at 25°C for 24 h in the system of pH = 5. The adsorption was considerably suppressed for the grafted samples prepared at the earlier stage of polymerization in the system with the polyfunctional monomers. The phenomenon was discussed in terms of the formation of crosslinked and branched structures in the MAA‐grafted chains depending on the polymerization stage in the system with polyfunctional monomers. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 1262–1268, 2006
Surface modification of monodisperse‐crosslinked polymeric microspheres using a redox initiation system
Authors: Jung Mi‐Ok , Ryu Jee‐Hyun , Park Jin‐Gyu , Jun Jung‐Bae , Suh Kyung‐Do
Published: January 2006

The surface modification of monodisperse‐crosslinked polymeric microspheres was carried out by introducing hydroxyl groups on the surface and utilizing the redox initiation system. The emulsions of the second monomer mixture were swollen into the monodisperse PS seed particles. The hydroxyl groups were introduced by hydrolysis of the acetate groups on the surface of microspheres. Ceric ammonium sulfate in sulfuric acid solution was employed to graft the acrylic monomer onto the polymeric microspheres. The surface characteristics of the surface‐modified particles were confirmed by FTIR, SEM, and TGA measurements. From the FE‐TEM image, a uniform coating layer was confirmed on the surface of microsphere. In DSC analysis, only an exothermal peak appeared when high content of DVB was used in the seeded polymerization, while, Tgs emerged after hydrolysis and graft polymerization using the low content of DVB in the second monomer. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 1349–1356, 2006
Acidic hydrolysis of a poly(vinyl acetate) matrix by the catalytic effect of Ag nanoparticles and the micellization of Ag‐metal‐containing polymer
Authors: Huang Chueh‐Jung , Shieu Fuh‐Sheng , Hsieh Wen‐Pin , Chang Teh‐Chou
Published: January 2006

In this study, we conveniently obtained Ag(0)–polymer nanocomposites by reacting AgNO3 with commercial poly(vinyl acetate) (PVAc) in the absence of a special reducing agent. The formation of Ag(0) metal was detected after formic acid (HCOOH) was added to a PVAc–AgNO3 complex system, and some of the acetate groups of the PVAc backbone were hydrolyzed to form hydroxyl groups (OH) under the catalytic effect of the reduced Ag(O) metal. Here, the structure of the partially hydrolyzed PVAc backbone was represented as PVOH‐PVAc. X‐ray diffraction spectra showed that the Ag(0) metal generated in this method was in the form of Ag crystals. The structure of the Ag(0)–polymer was analyzed by 1H‐NMR and 13C‐NMR spectroscopy. The micellization of the Ag(0)–polymer was also investigated by the addition of an inducing solvent to the formic acid solution of Ag(0)–polymer. The image showed that the morphology of the Ag micelles in the H2O‐induced solvent was a Ag corona with a Ag shell, and that in the p‐xylene induced solvent showed a Ag cluster core structure. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 1457–1464, 2006
Synthesis and characterization of reinforced acrylic‐based superabsorbents crosslinked with divinylbenzene
Authors: Huang Jian , Huang Zhi‐Ming , Bao Yong‐Zhong , Weng Zhi‐Xue
Published: January 2006

A series of superabsorbent polymers were synthesized by an inverse suspension polymerization, with potassium persulfate as the initiator, Span60 as the dispersant, and N,N′‐methylene bisacrylamide (BIS) and divinylbenzene (DVB) as multiple crosslinkers. The synthesis conditions, including the amount of dispersant, concentration of crosslinkers, oil‐to‐water phase ratio (O/W) of the polymerization system, total monomer concentration, and acrylamide (AM) content were studied. The results indicated that there were optima for the following properties: BIS crosslinker concentration (0.075 wt %), O/W (3 : 1), total monomer concentration (37.5 wt %), and AM content (5 wt %). In addition, the particle size had a significant influence on the absorption speed, and the absorption speed increased with decreasing particle size. In comparison with the conventional sample crosslinked only by BIS, the superabsorbent with the same particle size but crosslinked by multiple crosslinkers had the higher absorption rate because of surface crosslinking. It also showed that the salt resistance and antihydrolyzing property of the superabsorbent crosslinked by multiple crosslinkers (BIS and DVB) were enhanced, which was also attributed to surface crosslinking by DVB. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 1594–1600, 2006
Poly(silyl ester)s: A new route of synthesis via the condensation of Di‐tert‐butyl ester of dicarboxylic acid with dichlorosilane
Authors: Liu Zonglin , Han Nianfeng , Dong Jian
Published: January 2006

Poly(silyl ester)s were synthesized by a new route via the condensation of di‐tert‐butyl ester of dicarboxylic acid with dichlorosilane by the elimination of tert‐butyl chloride as a driving force. Three new poly(silyl ester)s with molecular weights typically ranging from 2000 to 5000 amu were produced by the condensation of di‐tert‐butyl adipate with 1,5‐dichloro‐1,1,5,5‐tetramethyl‐3,3‐diphenyl trisiloxane and di‐tert‐butyl fumarate with 1,5‐dichloro‐1,1,5,5‐tetramethyl‐3,3‐diphenyl trisiloxane or 1,3‐dichlorotetramethyl disiloxane. Each polymer was characterized with infrared, 1H‐NMR, and 13C‐NMR spectroscopy, gel permeation chromatography, differential scanning calorimetry, and thermogravimetric analysis. This new approach showed several advantages. First, it did not require a catalyst or solvent. Second, the tert‐butyl chloride byproduct was volatile and was easily eliminated. Third, there was no reaction between the growing poly(silyl ester)s and the condensation byproduct, tert‐butyl chloride. Fourth, the monomers could be readily purified. Finally, the polymerization could be performed at relatively low temperatures and in a short time. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 1378–1384, 2006
Photopolymerization of methyl methacrylate by 2,2′‐dithiodiethanol: Effect of reaction conditions
Authors: Baruah Smriti Rekha , Kakati Dilip Kumar
Published: January 2006

The photopolymerization of methyl methacrylate (MMA) through the use of a novel disulphide, 2,2′‐dithiodiethanol (DDE), was studied. This photoinitiator is of special interest because of its possible use in the synthesis of polyurethane macrophotoinitiator. The photopolymerization was carried out in the Heber multilamp photochemical reactor (COMPACT‐LP‐MP88) at 254 nm. The effects of reaction conditions on the polymerization of MMA were studied. It was observed that the percentage conversion and molecular weight increased with the increases of monomer concentration and reaction time. However, for the initiator to monomer molar ratio, there was a critical molar ratio for maximum conversion. The results suggested the living radical nature of the photoinitiator, which was further investigated by the preparation of block copolymer with acrylonitrile. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 1601–1606, 2006
Morphology and thermal behavior of MCPA6/SAN blends prepared by anionic ring‐opening polymerization of ϵ‐caprolactam
Authors: Hou Lianlong , Yang Guisheng
Published: January 2006

In this article, a series of blends of monomer casting polyamide 6 and styrene‐co‐acrylonitrile (MCPA6/SAN) were prepared by in situ anionic ring‐opening polymerization of ϵ‐caprolactam. Their morphology and thermal behaviors were investigated by means of scanning electron microscope, differential scanning calorimeter, and wide‐angle X‐ray diffraction (WAXD), respectively. The SAN phase had much finer domain in MCPA6/SAN than that in the PA6/SAN blends prepared by melt blending of PA6 and SAN. All the melting and crystallization parameters of MCPA6/SAN blends decreased gradually with the increase of SAN content, while the melting temperature was almost unchanged. These results were due to the hydrolysis reaction of SAN that occurred during the anionic polymerization of ϵ‐caprolactam. In addition, WAXD results showed that only α crystal forms existed in the MCPA6/SAN blends. In addition, the mechanical property of MCPA6 was improved obviously by incorporating a certain amount of SAN. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 1357–1363, 2006
Properties and preparation of compatibilized nylon 6 nanocomposites/ABS blends using functionalized metallocene polyolefin elastomer. I. Impact properties
Authors: Lai S.‐M. , Liao Y.‐C. , Chen T.‐W.
Published: January 2006

The impact behaviors of nanoclay‐filled nylon 6 (nano‐nylon 6) blended with poly(acrylonitrile–butadiene–styrene) terpolymers (ABS) prepared through a twin screw mixing process were investigated here using metallocene polyethylene grafted maleic anhydride (POE‐g‐MA) as a compatibilizer to enhance the interface interaction. No clear effect of compatibilizer on the dispersion of clay and crystalline structure of nano‐nylon 6 has been observed. In view of morphology and rheological behaviors, the effect of compatibilizer on the mechanical properties could be elucidated. It is found that impact strength increases with the addition of compatibilizer at various ABS compositions. Similar effects are also observed with decreasing test temperature at the nano‐nylon 6/ABS blend composition of 80/20. As for thermal properties, the heat distortion temperature shows a marginal decrease in the nano‐nylon 6/ABS blends. Rheological behavior indicates that increased viscosity is found for the investigated compatibilized systems. Through morphology observations, the etched ABS particle sizes tend to decrease with the addition of compatibilizer for the blends, but are larger with higher contents of ABS concentrations. Those observations account for impact behaviors of the investigated blends. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 1364–1371, 2006
Effect of elastomer type and functionality on the behavior of toughened polyamide nanocomposites
Authors: Kelnar I. , Kotek J. , Kaprálková L. , Hromádková J. , Kratochvíl J.
Published: January 2006

The only shortcoming of PA6‐based nanocomposites is low toughness, which is the same as that of the matrix. This work is focused on optimization of toughening these nanocomposites by introduction of small amounts of finely dispersed elastomers. A comparison of reactively compatibilized and analogous nonreactive elastomer‐containing nanocomposites indicates the best‐balanced mechanical behavior for polar nonreactive elastomers such as NBR and E‐MA. This is explained by a significant compatibilizing effect of clay. Besides the elastomer particle size and its properties, the clay localization and its degree of ordering in the interfacial region also significantly influenced mechanical properties of the system. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 1571–1576, 2006
Preparation and characterization of EVA–sisal fiber composites
Authors: Malunka M. E. , Luyt A. S. , Krump H.
Published: January 2006

In this work, composites of an EVA polymer matrix and short sisal fiber were characterized. The physical‐morphological as well as chemical interactions between EVA and sisal were investigated. When the samples were prepared in the presence of dicumyl peroxide, the results suggest that crosslinking of EVA as well as grafting between EVA and the sisal fibers took place. Morphological changes were studied by scanning electron microscopy (SEM). Results from Hg‐porosimetry, SEM, Fourier transform infrared spectroscopy, surface free energy, and gel content strongly indicate grafting of EVA onto sisal under the composite preparation conditions, even in the absence of peroxide. The grafting mechanism could not be confirmed from solid‐state 13C NMR analysis. The grafting had an impact on the thermal and mechanical properties of the composites, as determined by differential scanning calorimetry and tensile testing. Thermogravimetric analysis results show that the composites are more stable than both EVA and sisal fiber alone. The composite stability, however, decreases with increasing fiber content. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 1607–1617, 2006
A study of the synthesis, kinetics, and characterization of reactive graft copolymers of poly(vinyl imidazole) and cellulose for use as supports in enzyme immobilization and metal ion uptake
Authors: Chauhan Ghanshyam S. , Singh Baljit , Chauhan Sandeep , Dhiman Surya K. , Kumar Dinesh
Published: January 2006

In continuation to our earlier work to use bioresource for developing alternate materials for use at the interface of biotechnology and polymer science, we have utilized pine needles as a renewable stock of cellulose to synthesize graft copolymers of vinyl imidazole. Kinetics of N‐VIm by simultaneous γ‐irradiation method has been investigated as a function of total dose, monomer concentration, and amount of water. Effect of water–methanol solvent composition on graft yields and polymerization kinetics has also been studied at the optimum grafting conditions of the total dose and monomer concentration. Effect of some additives such as ZnCl2, Mohr salt, tetramethylethylene diamine, potassium persulfate, ammonium persulfate as grafting accelerators and promoters has also been studied. Graft copolymers have been characterized by elemental analysis, FTIR, and swelling studies. The graft copolymers have been used as supports for metal ions sorption, enzyme immobilization, and as potential biomimicking catalysts. Sorption behavior of Fe2+ ions and Cu2+ ions and the immobilization of bovine serum albumin and protease as a function of graft yield has been reported. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 1522–1530, 2006
Coagulation and sedimentation of bacteria using a highly biodegradable polymeric coagulant
Authors: Kawabata Nariyoshi , Fuse Tomoaki
Published: January 2006

Copolymer of acrylamide with N‐benzyl‐4‐vinylpyridinium chloride (PAAM‐co‐BVP) produced coagulation and sedimentation of Escherichia coli, Bacillus subtillus, Pseudomonas aeruginosa, and Staphylococcus aureus. Addition of more than 50 mg L−1 of PAAM‐co‐BVP produced bacterial flocks that precipitated at a rate of around 200 cm h−1. Supernatant population reduced in the range 1/30,000–1/25,000,000. Reduction of supernatant population was most effective when about 200 mg L−1 of PAAM‐co‐BVP was added. PAAM‐co‐BVP was highly biodegradable and the half‐life estimated was 2.4 days when treated with activated sludge. The ratio of biochemical oxygen demand for 5 days (BOD5) to total organic carbon (TOC) was 0.607. Coagulation and sedimentation of bacteria using PAAM‐co‐BVP is expected to improve the water disinfection processes by saving chlorine and other hazardous chemical fungicides and by reducing the formation of trihalomethanes and other toxic chemical materials. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 1618–1623, 2006
Poly(ε‐caprolactone)‐grafted acetylated anhydroglucose oligomer by ring‐opening polymerization—Synthesis and characterization
Authors: Gädda Thomas , Kylmä Janne , Tuominen Jukka , Mikkonen Hannu , Laine Aki , Peltonen Soili , Seppälä Jukka
Published: January 2006

A novel acetylated anhydroglucose oligomer (AGU‐oligomer), prepared by acid catalyzed transglycosidation of potato starch triacetate and ethylene glycol, was used as a multifunctional coinitiator for the ring‐opening polymerization of ε‐caprolactone (ε‐CL). The polymers were synthesized using different weight ratios of the starting materials and were characterized by NMR, SEC, and MALLS. The results confirmed the expected P(AGU/CL) polymer structure, namely a ‘comb‐like’ graft‐copolymer having the AGU oligomer as backbone with PCL grafts of variable chain lengths (LCL = 4–21). Thermal and mechanical properties of graft‐copolymers with different ε‐CL block lengths were examined. By changing the graft length, crystallinity was controlled and amorphous polymers were obtained with AGU‐oligomer contents higher than 50 wt %. The tensile properties varied with the composition and a copolymer having 40 wt % of AGU‐oligomer behaved like soft elastomer, showing high elongation at break. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 1633–1641, 2006
Comparison of propylene/ethylene copolymers prepared with different catalysts
Authors: Stephens C. H. , Poon B. C. , Ansems P. , Chum S. P. , Hiltner A. , Baer E.
Published: January 2006

This study compared a series of experimental propylene/ethylene copolymers synthesized by a transition metal‐based, postmetallocene catalyst (xP/E) with homogeneous propylene/ethylene copolymers synthesized by conventional metallocene catalysts (mP/E). The properties varied from thermoplastic to elastomeric over the broad composition range examined. Copolymers with up to 30 mol % ethylene were characterized by thermal analysis, density, atomic force microscopy, and stress–strain behavior. The xP/Es exhibited noticeably lower crystallinity than mP/Es for the same comonomer content. Correspondingly, an xP/E exhibited a lower melting point, lower glass transition temperature, lower modulus, and lower yield stress than an mP/E of the same comonomer content. The difference was magnified as the comonomer content increased. Homogeneous mP/Es exhibited space‐filling spherulites with sharp boundaries and uniform lamellar texture. Increasing comonomer content served to decrease spherulite size until spherulitic entities were no longer discernable. In contrast, axialites, rather than spherulites, described the irregular morphological entities observed in xP/Es. The lamellar texture was heterogeneous in terms of lamellar density and organization. At higher comonomer content, embryonic axialites were dispersed among individual randomly arrayed lamellae. These features were characteristic of a copolymer with heterogeneous chain composition. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 1651–1658, 2006
Thermogravimetric analysis of agricultural residues: Oxygen effect and environmental impact
Authors: Šimkovic Ivan , Csomorová Katarína
Published: January 2006

Agricultural by‐products (wheat straw, WS; sugar beet, SB; corn cobs, CC; rape extracted meal, REM; soya bean hulls, SBH; bagasse, B; almond shells, AS; and olive stones; OS) were analyzed by dynamic and isothermal thermogravimetry (TG) in inert and oxidative environment. The goal was to evaluate the effect of oxygen presence on thermolysis and to compare the environmental impact of individual samples. In the inert environment at 250°C, the sequence according to decreasing residue amount under dynamic conditions is B (95%) > CC > WS > SBH = AS > OS > REM > SB (80%). This represents the decreasing role of hemicellulose and pectin components on thermal stability of individual samples. At 500°C the order changed to: REM (35%) > OS > AS > SB > SBH > B > CC > WS (24%). The TG/derivative thermogravimetry (DTG) values determined in air atmosphere could not be used for determination of individual macromolecular components due to overlapping of DTG maxima. For most of the studied samples, the measured residues under dynamic conditions were greater in the inert than in the oxidative environment. According to the thermooxidation maxima, the maximal difference of measured residues on dynamic TG curves run in nitrogen and oxygen environments in the order of decreasing thermooxidation resistance: B (32%; 325°C) > AS (29%; 450°C) > OS (23%; 450°C) > SBH (20%; 475°C) > WS (21%; 300°C) > SB (13%; 325°C) > REM (15%; 500°C). This is due to the largest protein content of REM (29%) as well as pectin, hemicellulose, and lignin composition of samples. Under isothermal conditions the rate constants were determined by linear regression method and are considered as initial rate constants of material degradation. For inert conditions, the smallest rate constants and biggest activation energy (E*) were determined on CC. The values of the rate constants increase in the following order CC < WS < SBH < B < OS < AS < SB < REM. In general it can be concluded that the rate constant values measured in oxygen are greater than analogical values measured in nitrogen. The determined E* values in oxygen were greater for AS, WS, B, SBH, and OS than the analogical values determined in nitrogen. They were decreasing in the following order: AS > WS > B > SBH > OS. On CC, SB and REM, E* values were lower in comparison with the E* calculated for inert conditions. We assume that when the E* value decreased in the presence of oxygen and when simultaneously smaller residue was formed under dynamic conditions, then the material is more unsuitable as a fuel from environmental point of view. It is because more oxygen was consumed and more material was gasified than on samples with closer values in both environments. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 1318–1322, 2006
A microindentation study of polyethylene composites produced by hot compaction
Authors: Orench I. Puente , Calleja F. J. Balta , Hine P. J. , Ward I. M.
Published: January 2006

Microindentation measurements are reported on a range of single polymer polyethylene (PE) composites, which are produced by hot compaction of high modulus PE fibers. It is possible to measure two hardness values, parallel and perpendicular to the fiber direction respectively, from which the microindentation anisotropy is defined. The hardness values relate to the instantaneous elastic recovery of the fibers, and the results show that the microindentation measurement is deforming a material volume below the surface of the sheets comparable to the dimensions of the fibers. It appears that the microindentation anisotropy approaches a limiting value with increasing fiber orientation, i.e., as the Young's modulus of the fibers increases. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 1659–1663, 2006
Study on the electrodriven action of gelatin hydrogel in silicone oil
Authors: Liu Genqi , Zhao Xiaopeng
Published: January 2006

Action of gelatin hydrogel crosslinked with glutaraldehyde under dc electric field of high voltage was studied. The experimental results show that the hydrogel can be driven by dc electric field of high voltage in the medium of silicone oil, and the action of the hydrogel is composed of rotation and translation. There is a low critical applied voltage of 0.5 kV, below which the action of the hydrogel may not be observed. The motion velocity and angle of the rotation of gelatin hydrogel are influenced by the electric field intensity. Because silicone oil is very stable and hard to electrolyze in electric field, gas formation associated with the electrolysis of water, which is inevitable and disadvantageous in conventional system of electric‐stimulus‐response hydrogel, would not happen. Our work has provided a novel kind of electrodriven methods for hydrogels. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 1664–1667, 2006
Two invaders achieve higher densities in reserves
Authors: Klinger Terrie , Padilla Dianna K. , Britton‐Simmons Kevin
Published: January 2006

Invasive species threaten marine biodiversity on a global scale.

To test whether marine reserves provide resistance to invading species, the abundance of two conspicuous invaders, a seaweed and an oyster, were measured inside marine reserves and in comparable areas outside reserves in north‐western Washington State.

Densities of both invaders were significantly higher in marine reserves than in comparable unprotected areas outside reserves. Although the causal mechanisms have not yet been identified, differential rates of human harvest do not appear to be responsible for the patterns observed.

It is provisionally suggested that physical or biological aspects of the reserves themselves may directly or indirectly facilitate biological invasion.

Copyright © 2006 John Wiley & Sons, Ltd.
The impact of glycosylation on HLA–DR1–restricted T cell recognition of type II collagen in a mouse model
Authors: von Delwig Alexei , Altmann Daniel M. , Isaacs John D. , Harding Clifford V. , Holmdahl Rikard , McKie Norman , Robinson John H.
Published: January 2006

Objective

Type II collagen (CII) is a candidate autoantigen implicated in the pathogenesis of rheumatoid arthritis (RA). Posttranslational glycosylation of CII could alter intracellular antigen processing, leading to the development of autoimmune T cell responses. To address this possibility, we studied the intracellular processing of CII for presentation of the arthritogenic glycosylated epitope CII259–273 to CD4 T cells in macrophages from HLA–DR1–transgenic mice.

Methods

HLA–DR1–transgenic mice were generated on a class II major histocompatibility complex–deficient background, and T cell hybridomas specific for the glycosylated and nonglycosylated epitope CII259–273 were developed. Subcellular fractionation of macrophages was used to localize CII degradation to particular compartments and to identify the catalytic subtype of proteinases involved.

Results

We showed that the glycosylated CII259–273 epitope required more extensive processing than did the nonglycosylated form of the same epitope. Dense fractions containing lysosomes were primarily engaged in the processing of CII for antigen presentation, since these compartments contained 1) enzyme activity that generated antigenic CII fragments bearing the arthritogenic glycosylated epitope, 2) the antigenic CII fragments themselves, 3) CII peptide–receptive HLA–DR1 molecules, and 4) peptide/HLA–DR1 complexes that could directly activate T cell hybridomas. Degradation of CII by dense fractions occurred optimally at pH 4.5 and was abrogated by inhibitors of serine and cysteine proteinases.

Conclusion

Processing of the arthritogenic glycosylated CII259–273 epitope, which is implicated in the induction of autoimmune arthritis, is more stringently regulated than is processing of the nonglycosylated form of the same epitope. Mechanisms of intracellular processing of the glycosylated epitope may constitute novel therapeutic targets for the treatment of RA.
Prevention of spontaneous arthritis by inhibiting homeostatic expansion of autoreactive CD4+ T cells in the K/BxN mouse model
Authors: Jang Eunkyeong , Kim Hong Ro , Cho Sin Hye , Paik Doo‐Jin , Kim Jung Mogg , Lee Sang‐Koo , Youn Jeehee
Published: January 2006

Objective

K/BxN‐transgenic mice are a model of autoimmune arthritis, similar to rheumatoid arthritis. This study was undertaken to determine whether inhibition of lymphopenia‐provoked homeostatic expansion can prevent spontaneous development of disease in the K/BxN model.

Methods

To inhibit homeostatic expansion of autoreactive T cells, K/BxN mice with disease in the preclinical stage were adoptively transferred with CD4+ T cells purified from nontransgenic BxN or Thy1.1+ BxN mice. To observe the profile of proliferation of CD4+ T cells derived from the hosts, carboxyfluorescein diacetate succinimidyl ester–labeled autologous CD4+ T cells were cotransferred to K/BxN mice together with BxN CD4+ T cells. Disease onset and progression were scored, and the dynamics and phenotypes of recipient CD4+ T cells were determined by flow cytometry, before and after cell infusion.

Results

During the preclinical phase of disease, K/BxN mice exhibited CD4+ T lymphopenia, which was followed by a compensatory expansion of these cells during the early clinical phase. The majority of CD4+ T cells acquired a memory phenotype (CD44high,CD62Llow,CD25−), which is a hallmark of homeostatically expanding cells. Importantly, K/BxN mice subjected to syngeneic T cell transfer did not develop symptoms of arthritis and also possessed fewer transgenic T cell receptor–encoded Vβ6+,CD4+ T cells. This effect was associated with decreased proliferation of recipient‐derived CD4+ T cells but not with the function of CD25+ T regulatory cells present in donor cells.

Conclusion

These results provide the first evidence that lymphopenia‐associated homeostatic proliferation of autoreactive CD4+ T cells potentiates autoimmune arthritis, and that inhibition of this process protects mice from the development of this pathologic condition.
Treatment for rheumatoid arthritis and the risk of hospitalization for pneumonia: Associations with prednisone, disease‐modifying antirheumatic drugs, and anti–tumor necrosis factor therapy
Authors: Wolfe Frederick , Caplan Liron , Michaud Kaleb
Published: January 2006

Objective

Pneumonia is a major cause of mortality and morbidity in rheumatoid arthritis (RA). This study was undertaken to determine the rate and predictors of hospitalization for pneumonia and the extent to which specific RA treatments increase pneumonia risk.

Methods

RA patients (n = 16,788) were assessed semiannually for 3.5 years. Pneumonia was confirmed by medical records or detailed patient interview. Covariates included RA severity measures, diabetes, pulmonary disease, and myocardial infarction. Cox proportional hazards regression was used to determine the multivariable risk associated with RA treatments.

Results

After adjustment for covariates, prednisone use increased the risk of pneumonia hospitalization (hazard ratio [HR] 1.7 [95% confidence interval 1.5–2.0]), including a dose‐related increase in risk (≤5mg/day HR 1.4 [95% confidence interval 1.1–1.6], >5–10 mg/day HR 2.1 [95% confidence interval 1.7–2.7], >10 mg/day HR 2.3 [95% confidence interval 1.6–3.2]). Leflunomide also increased the risk (HR 1.2 [95% confidence interval 1.0–1.5]). HRs for etanercept (0.8 [95% confidence interval 0.6–110]) and sulfasalazine (0.7 [95% confidence interval 0.5–1.0]) did not reflect an increased risk of pneumonia. HRs for infliximab, adalimumab, and methotrexate were not significantly different from zero.

Conclusion

There is a dose‐related relationship between prednisone use and pneumonia risk in RA. No increase in risk was found for anti–tumor necrosis factor therapy or methotrexate. These data call into question the belief that low‐dose prednisone is safe. Because corticosteroid use is common in RA, the results of this study suggest that prednisone exposure may have important public health consequences.
The LUNDEX, a new index of drug efficacy in clinical practice: Results of a five‐year observational study of treatment with infliximab and etanercept among rheumatoid arthritis patients in southern Sweden
Authors: Kristensen Lars Erik , Saxne Tore , Geborek Pierre
Published: January 2006

Objective

To describe the use of the LUNDEX, a new index for comparing the long‐term efficacy and tolerability of biologic therapies in rheumatoid arthritis (RA) patients treated in clinical practice.

Methods

Patients (n = 949) with active RA that had not responded to at least 2 disease‐modifying antirheumatic drugs (DMARDs) including methotrexate, in whom biologic therapy was being initiated, were included in a structured clinical followup protocol. The protocol included collection of data on diagnosis, disease duration, previous and ongoing DMARD treatment, and dates on which biologic treatment was started and terminated. In addition, data on efficacy measures used for calculating validated response criteria, i.e., the European League Against Rheumatism and American College of Rheumatology response criteria, were collected at fixed time points. Data were prospectively registered from March 1999 through January 2004. The LUNDEX, a new index combining the proportion of patients fulfilling a selected response criteria set with the proportion of patients adhering to a particular therapy, was designed to compare the efficacy of the different therapies.

Results

Etanercept had higher overall LUNDEX values compared with infliximab, mostly because of a lower rate of adherence to therapy with infliximab. The relationship between the drugs was consistent irrespective of the response criteria used.

Conclusion

The LUNDEX is a valuable tool for evaluating drug efficacy in observational studies. It has the advantage of integrating clinical response as well as adherence to therapy in a composite value. Moreover, the LUNDEX has a practical and potentially universal application independent of diagnosis and response criteria.
Signaling pathways regulating intercellular adhesion molecule 1 expression by endothelin 1: Comparison with interleukin‐1β in normal and scleroderma dermal fibroblasts
Authors: Waters Charlotte E. , Shi‐Wen Xu , Denton Chris P. , Abraham David J. , Pearson Jeremy D.
Published: January 2006

Objective

Endothelin 1 (ET‐1) has been implicated in the pathogenesis of fibrotic and inflammatory diseases, including scleroderma. In addition to modulating vascular tone and extracellular matrix turnover, ET‐1 up‐regulates cell surface adhesion molecules including intercellular adhesion molecule 1 (ICAM‐1), which is key to cell–cell and cell–matrix adhesion and leukocyte infiltration. This study was undertaken to delineate the signal transduction pathways utilized by ET‐1 and compare them with those adopted by proinflammatory cytokine interleukin‐1β (IL‐1β) in normal and scleroderma dermal fibroblasts.

Methods

Protein expression induced by ET‐1 and IL‐1β on normal dermal fibroblasts, with or without signaling inhibitors, was detected by enzyme‐linked immunosorbent assay, while messenger RNA (mRNA) levels were analyzed by LightCycler polymerase chain reaction. Expression of protein kinase Cδ (PKCδ) and PKCϵ protein in normal dermal fibroblasts and scleroderma dermal fibroblasts was determined by Western blotting, and PKCϵ involvement in ET‐1 signaling was confirmed through transfection of an ICAM‐1 promoter construct into murine PKCϵ−/− fibroblasts. NF‐κB activation was confirmed via electrophoretic mobility supershift assay, and analysis of the ICAM‐1 promoter region was achieved via transfection of deletion constructs into human dermal fibroblasts.

Results

In normal dermal fibroblasts, ET‐1 induced ICAM‐1 mRNA and surface protein expression in a dose‐ and time‐dependent manner via both receptor subtypes, ETA and ETB; antagonism of both abolished the ET‐1 response. MEK was involved in the signaling cascade, but phosphatidylinositol 3‐kinase and p38 MAPK were not. Key to the cascade was activation of NF‐κB, achieved by ligation of either receptor subtype. PKCϵ activation led to downstream activation of MEK and, in part, NF‐κB. IL‐1β signaling required NF‐κB and MEK activation, along with activation of PKCδ. ET‐1 and IL‐1β each utilized the same ICAM‐1 promoter region and the same NF‐κB site at –157 bp. Responses to ET‐1 and IL‐1β differed in scleroderma dermal fibroblasts, with ET‐1 sensitivity decreasing and IL‐1β responses remaining intact. Expression of PKCϵ and PKCδ in scleroderma dermal fibroblasts was also altered.

Conclusion

The findings of this study indicate that differences in sensitivity to ET‐1 and IL‐1β in scleroderma dermal fibroblasts may be explained by altered expression of the PKC isoforms and cytokine receptors.
Risk genotypes in folate‐dependent enzymes and their association with methotrexate‐related side effects in rheumatoid arthritis
Authors: Weisman Michael H. , Furst Daniel E. , Park Grace S. , Kremer Joel M. , Smith Katie M. , Wallace Daniel J. , Caldwell Jacques R. , Dervieux Thierry
Published: January 2006

Objective

Methotrexate (MTX) is an antifolate agent that is often associated with toxicity. This study investigated whether risk genotypes for folate‐dependent enzymes are associated with the toxicity of MTX in patients with rheumatoid arthritis (RA).

Methods

Blood was collected for analysis in a muticenter, cross‐sectional study of RA patients who had been receiving MTX for at least 1 month prior to enrollment, and side effects occurring at the time of a single study visit were recorded. Low‐penetrance risk genotypes in methylenetetrahydrofolate reductase (MTHFR) 677TT, thymidylate synthase (TSER) *2/*2 (variable number of tandem repeats), amino imidazole ribonucleotide transformylase (ATIC) 347GG, and serine hydroxymethyltransferase (SHMT1) 1420CC were measured and summed to constitute the toxicogenetic index specific to each patient. Statistical analyses consisted of logistic regression models with clustered‐center effects, and associations with risk genotypes were expressed as adjusted odds ratios (ORs).

Results

Among 214 patients enrolled at 4 study sites, a total of 67 patients (31%) presented with a side effect (gastrointestinal event, headache, lethargy, alopecia, cough, or dyspnea). Risk genotypes associated with side effects in the central nervous system were MTHFR 677TT (OR 3.3, P < 0.01) and SHMT1 1420CC (OR 2.4, P < 0.05). ATIC 347GG was associated with gastrointestinal side effects (OR 3.0, P < 0.01), while TSER*2/*2 (OR 5.4, P < 0.01) and SHMT1 1420CC (OR 3.2, P < 0.01) were associated with alopecia. The toxicogenetic index ranged from 0 to 3 (median 1). An index of 3 was associated with an ∼7‐fold higher likelihood of having a side effect compared with an index of 0 (P < 0.01).

Conclusion

These data suggest that a composite index of the cumulative risk genotypes in folate‐dependent enzymes may be an effective means of profiling RA patients who develop side effects to MTX.
Reconstitution of peripheral blood B cells after depletion with rituximab in patients with rheumatoid arthritis
Authors: Leandro Maria J. , Cambridge Geraldine , Ehrenstein Michael R. , Edwards Jonathan C. W.
Published: January 2006

Objective

To study the quantitative and phenotypic reconstitution of peripheral blood B cells and its relationship to the dynamics of clinical response in patients with rheumatoid arthritis (RA) following B cell depletion with rituximab.

Methods

Twenty‐four patients with active RA treated with rituximab were studied. Flow cytometry with combinations of monoclonal antibodies to B cell and T cell subsets was used.

Results

The frequency and total number of CD19+ cells in the peripheral blood decreased a mean of 97% for more than 3 months in all but 1 patient following rituximab therapy. All B cell populations were depleted. More than 80% of residual B cells showed a memory or plasma cell precursor phenotype. B cell repopulation occurred a mean of 8 months after treatment and was dependent on the formation of naive B cells, which showed an increased expression of CD38 and CD5. During repopulation, increased numbers of circulating immature B cells, CD19+,IgD+,CD38high,CD10low,CD24high cells, were identified. Patients who experienced a relapse of RA on return of B cells tended to show repopulation with higher numbers of memory B cells. A small number of T cells and natural killer cells expressed low levels of CD20. These cells were depleted following rituximab therapy and returned to the circulation a mean of 5 months after treatment. No other significant changes were detected in the T cell populations studied.

Conclusion

Rituximab induced a profound depletion of all peripheral blood B cell populations in patients with RA. Repopulation occurred mainly with naive mature and immature B cells. Patients whose RA relapsed on return of B cells tended to show repopulation with higher numbers of memory B cells.