bluuebunny/crossref_metadata_2025 huggingface dataset:
Progressive mitochondrial disease resulting from a novel missense mutation in the mitochondrial DNA ND3 gene
Authors: Taylor Robert W. , Singh‐Kler Rajinder , Hayes Christine M. , Smith Philip E.M. , Turnbull Douglass M.
Published: September 2002

We describe a 42‐year‐old man who presented with a progressive history of epilepsy, stroke‐like episodes, bilateral optic atrophy, and cognitive decline. Investigation of his muscle biopsy revealed a specific defect in complex I activity. Subsequent analysis of the mitochondrial genome identified a novel heteroplasmic T10191C mutation in the ND3 gene. The mutation was present at lower levels in blood from the patient and unaffected maternal relatives and is the first pathogenic mitochondrial DNA mutation in the ND3 gene to be described.
Synthesis and characterization of coordination compounds of organotin(IV) with nitrogen and sulfur donor ligands
Authors: Singh Har Lal , Varshney A. K.
Published: September 2002

The reactions of dimethyltin dichloride with nitrogen and sulfur donor ligands derived by condensation of S‐benzyldithiocarbazate with indol‐3‐carboxylaldehyde, thiophene‐2‐aldehyde and furfuraldehyde have been investigated in 1:1 and 1:2 molar ratios in anhydrous alcohol. These ligands act as mononegatively charged bidentate species and coordinate to the central tin(IV) atom through the thiosulfur by proton exchange with the azomethine nitrogen. The newly synthesized complexes have been characterized by elemental analysis, conductance measurements and molecular weight determinations. The mode of bonding and the geometry of the complexes have been suggested on the basis of infrared, electronic and 1H, 13C and 119Sn NMR spectroscopy, and probable structures have been assigned to these complexes. A few representative ligands and their tin(IV) complexes have also been screened for their antifungal and antibacterial activities and found to be quite active in this respect. Copyright © 2001 John Wiley & Sons, Ltd.
Arsenic concentrations and speciation in the tissues of ringed seals (Phoca hispida) from Pangnirtung, Canada
Authors: Ebisuda Ken‐ichi , Kunito Takashi , Kubota Reiji , Tanabe Shinsuke
Published: September 2002

Concentrations of total arsenic and arsenic compounds were determined in tissues of ringed seals (Phoca hispida) using hydride generation–atomic absorption spectrometry and high‐performance liquid chromatography–inductively coupled plasma mass spectrometry. Arsenic was accumulated at high concentrations in the blubber as lipid‐soluble arsenic compounds (arsenolipids). Arsenobetaine (AB) was the most predominant arsenical in the liver, kidney, muscle and gonad, accounting for about 70% of total arsenic in these tissues. Significant positive correlations were observed for AB concentrations among liver, kidney, muscle and gonad, suggesting that the distribution of AB among these tissues was at equilibrium. Concentrations of AB in the tissues were elevated up to 1–3 years of age, and then fell to a lower level. In contrast, dimethylarsinic acid concentration was significantly increased with age in the liver and kidney. Arsenocholine was also detected in the liver, kidney and gonad, but was not detected in the muscle. Among the arsenic compounds, only AB showed a considerable decrease of the concentration in the gastrointestinal contents with their passing through the gastrointestinal tract, which might indicate that the absorption rate of AB was higher than the absorption rates of other arsenic compounds in ringed seals. To our knowledge, this is the first report of arsenic speciation in several tissues and gastrointestinal contents in marine mammals. Copyright © 2002 John Wiley & Sons, Ltd.
Urinary arsenic species in an arsenic‐affected area of West Bengal, India
Authors: Tokunaga Hiroshi , Roychowdhury Tarit , Chandraskaran N. , Uchino Tadashi , Ando Masanori
Published: September 2002

Arsenic contamination of groundwater and associated medical problems have long been reported in the Mushidabad district, one of nine arsenic‐affected districts in West Bengal, India. In order to estimate people's total exposure to arsenic, we visited 12 arsenic‐affected families in that area during 4–7 December 2000 and collected seven tubewell waters used for drinking, cooking and other household purposes and 51 urine samples from those families. The arsenic concentrations in drinking water ranged from 2.7 to 170 ppb. Those families designated A–E, G–I and J took in arsenic concentrations of 72.6 ppb, 154 ppb and 170 ppb respectively. The concentrations of arsenite, arsenate, monomethylarsonic acid (MMA) and dimethylarsinic acid (DMA) in urine (corrected for creatinine level in the urine), obtained from 51 persons, ranged from 0 to 796.9 ppb (mg creatinine/ml urine)−1, from 0 to 1635.2 ppb (mg creatinine/ml urine)−1, from 2.1 to 411.0 ppb (mg creatinine/ml urine)−1 and from 8.3 to 2017.5 ppb (mg creatinine/ml urine)−1 respectively. The average concentration of total arsenic was 59.2 ppb (mg creatinine/ml urine)−1. On comparison of the ratios of (MMA + DMA) to total arsenic, the average proportion of (MMA + DMA) was 83.2%, but the proportions were 27.3% and 16.5% for two of the children (2 years old and 13 years old respectively). This result suggested that they might be damaged due to the methylating capacity. When estimating arsenic species in urine obtained from families A–E, G–I and J, these family members normally metabolized the inorganic arsenic to MMA and DMA and eliminated these as such in comparison with an intake of inorganic arsenic from the tubewell water. The arsenic species in urine from people having the same food and life habits showed the same profile in both men and women. There was a good correlation (p < 0.05) between the ages of 19 persons in families A–E and the values of (MMA + DMA) or total arsenic in urine. Copyright © 2002 John Wiley & Sons, Ltd.
Investigation on preparation and protein release of biodegradable polymer microspheres as drug‐delivery system
Authors: Zhou Shaobing , Deng Xianmo , Yuan Minglong , Li Xiaohong
Published: September 2002

Among the different approaches to achieve protein delivery, the use of polymers, especially biodegraded, holds great promise. This work aimed to study the preparation and protein release of a novel drug‐delivery system based on human serum albumin (HSA) encapsulated into biodegradable polymer microspheres. The microspheres containing HSA were elaborated by the solvent‐extraction method based on the formation of multiple w/o/w emulsion. The encapsulation efficiency (E.E.) of HSA was determined by the CBB method. Alginate/alginate and calcium chloride was added into an internal aqueous phase to investigate the protein loading efficiency, protein stability, and in vitro release profiles. Microspheres were characterized in terms of their morphology, size distribution, loading efficiency, and in vitro protein release. SDS–PAGE results showed that HSA kept its structural integrity during the encapsulation and release procedure. In vitro studies indicated that the microspheres with alginate added in the internal aqueous phase had a smaller extent of burst release. In conclusion, the work presents a new approach for macromolecular drugs (such as protein drugs, vaccines, and peptide drugs) delivery. © 2002 John Wiley & Sons, Inc. J Appl Polym Sci 84: 778–784, 2002; DOI 10.1002/app.10327
Structure‐property relationships of LLDPE—highly filled with aluminum hydroxide
Authors: Wang Genlin , Jiang Pingkai , Zhu Zikang , Yin Jie
Published: September 2002

The mechanical performance, rheological behavior, and phase morphology of linear low‐density polyethylene (LLDPE) highly loaded with aluminum hydroxide [Al(OH)3] were investigated. It was found that titanate surface‐active agent and ethylene‐vinyl acetate copolymer (EVA) improve the processing and ductile properties of the composite remarkably but are accompanied by the deterioration of the tensile strength. Addition of vinyl triethoxy silane (VTEO) and dicumyl peroxide (DCP) improves the tensile strength of the composite because of the silane crosslinking structure introduced. A synergistic effect of interface modifying and silane crosslinking method in improving mechanical performance of the composite is presented. Phase morphology of the LLDPE/Al(OH)3 composites was studied by means of scanning electron microscopy (SEM) technique. SEM micrographs indicate that a core‐shell type with Al(OH)3 as a core and EVA as a shell is formed in the composite. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 2485–2490, 2002
Synthesis, characterization, and properties of polychelates of poly(styrene sulfonic acid‐co‐maleic acid) with Co(II), Cu(II), Ni(II), and Zn(II)
Authors: Rivas B. L. , Seguel G. V. , Geckeler K. E.
Published: September 2002

Polymer metal complexes of poly(styrene sulfonic acid‐co‐maleic acid) and Cu(II), Ni(II), Co(II), and Zn(II) were synthesized. The magnetic, spectral, and thermal properties, as well as the electrical conductivities, of the chelates were investigated, and possible structures were assigned to the polychelates. Semiempirical calculations at the AM1 level were carried out on the geometrical arrangement of the polychelates. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 2546–2551, 2002
Thermal degradation of film cast from aqueous polyurethane dispersions
Authors: Lu M. G. , Lee J. Y. , Shim M. J. , Kim S. W.
Published: September 2002

In this paper, water‐dispersible polyurethanes based on isophorone diisocyanate and polytetramethylene glycol were synthesized, and their thermal degradation behavior under nitrogen and air was studied by thermogravimetric (TG) analysis. The influence of NCO/OH ratio and functional group concentration was discussed. The thermal decomposition kinetics under nonisothermal conditions was analyzed using Ozawa method. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 2552–2558, 2002
Morphology and thermal and mechanical properties of PBT/HIPS and PBT/HIPS‐g‐GMA blends
Authors: Yang Huili , Lai Mingfang , Liu Wanjun , Sun Chunrong , Liu Jiangjiang
Published: September 2002

The modification of high‐impact polystyrene (HIPS) was accomplished by melt‐grafting glycidyl methacrylate (GMA) on its molecular chains. Fourier transform infrared spectroscopy and electron spectroscopy for chemical analysis were used to characterize the formation of HIPS‐g‐GMA copolymers. The content of GMA in HIPS‐g‐GMA copolymer was determined by using the titration method. The effect of the concentrations of GMA and dicumyl peroxide on the degree of grafting was studied. A total of 1.9% of GMA can be grafted on HIPS. HIPS‐g‐GMA was used to prepare binary blends with poly(buthylene terephthalate) (PBT), and the evidence of reactions between the grafting copolymer and PBT in the blends was confirmed by scanning electron microscopy (SEM), dynamic mechanical analysis, and its mechanical properties. The SEM result showed that the domain size in PBT/HIPS‐g‐GMA blends was reduced significantly compared with that in PBT/HIPS blends; moreover, the improved strength was measured in PBT/HIPS‐g‐GMA blends and results from good interfacial adhesion. The reaction between ester groups of PBT and epoxy groups of HIPS‐g‐GMA can depress crystallinity and the crystal perfection of PBT. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 2600–2608, 2002
Model for thickness effect with impact testing of viscoelastic materials
Authors: Kim Ho Sung , Shafig Robert M.
Published: September 2002

Thickness effect on impact parameters is studied and a model is developed for flat‐ended drop weight impact testing of viscoelastic materials. The model represents a relationship of specimen thickness with impact force/stress and impact energy. A polymeric material, ethylene vinyl acetate (EVA), was used for experimental verification. Experimental results for a thickness range of 1–9 mm at impact energy levels of 0.42, 0.96, and 1.54 J have been found to be in reasonable agreement with predictions based on the model with some approximated parameters. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 1762–1767, 2001
Formulation and mechanical characterization of PVC plastisols based on low‐toxicity additives
Authors: Jimenez A. , Lopez J. , Iannoni A. , Kenny J. M.
Published: September 2002

New formulations of plastisols based on low‐toxicity plasticizers were proposed and characterized. Traditional phthalate plasticizers were replaced in the plastisols studied in this research by polymeric plasticizers (i.e., saturated polyesters), produced by the reaction of a diol and a carboxylic acid. The main drawback for the use of these plasticizers in formulations of PVC plastisols is a significant increase of the paste viscosity, which decreases their processability; thus, the use of additional additives to reduce viscosity is recommended. This study also includes the optimization of the processing conditions (cure temperature and time) of the proposed plastisols: complete cure was obtained at 140°C and 10 min. It is reported that the final properties of plastisols are very sensitive with respect to the processing conditions; in fact, insufficient plasticization or degradation can affect the material when processed out of the optimum conditions. The influence of the plasticizer concentration on mechanical and optical properties, such as tensile strength, hardness, brightness, and the like, is also reported. In summary, the proposed plastisols, with low‐toxicity plasticizers, offer a valid alternative to traditional PVC plastisols based on phthalate plasticizers. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 1881–1890, 2001
Junction properties of metal/polypyrrole Schottky barriers
Authors: Abthagir P. Syed , Saraswathi R.
Published: September 2002

Schottky barriers of the type Au/polypyrrole/Al (or In) were made in sandwich configuration. The conductivity of polypyrrole was tuned to be on the order of 10−3 ohm−1 cm−1 by its electrodeposition from a novel ambient temperature ternary eutectic melt consisting of acetamide, urea, and ammonium nitrate. The rectification characteristics were obtained from the current–voltage and capacitance–voltage measurements at room temperature. The analysis of data using thermionic emission theory gave improved values for the junction parameters of ideality factor, reverse saturation current, rectification ratio, and barrier potential when compared to the previously reported values for this polymer. Between Al and In metals used for the junction formation, the diode formed with Al metal is found to show better performance. The energy gap and work function of polypyrrole were also estimated. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2127–2135, 2001
Oriented crystallization in fiber formation: Inferences from the structure and properties of melt spun syndiotactic polypropylene filaments
Authors: Sura Ravi K. , Desai Prashant , Abhiraman A. S.
Published: September 2002

In processes, such as melt spinning, the crystallization behavior of syndiotactic polypropylene (sPP) is found to be substantially different from that of most other linear polymers. The anisotropic stress field in such processes leads invariably to extension as well as alignment (orientation) of the chains in the melt, both of which contribute usually to dramatic enhancement in the rate of crystallization. However, since the primary structure of the sPP chain in its most preferred crystal form is comprised of a “coiled helical,” (T2G2)2, sequence, stress‐induced chain extension can lead to conformational sequences that are not favorable for crystallization in this form. As a consequence, process conditions that generate higher stress levels can cause a diminution in the rate of crystallization of this polymer. Such conformation‐related aspects of oriented crystallization of sPP have been addressed through an analysis of the structure and properties of melt‐spun fibers, produced over a range of spinning speeds. The results serve to identify a refinement that is needed in current models of oriented crystallization and also a mechanism to promote the nucleation of crystallization of sPP. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2305–2317, 2001
Modification of bismaleimide resin by poly(ethylene phthalate‐co‐ethylene terephthalate), poly(ethylene phthalate‐co‐ethylene 4,4′‐biphenyl dicarboxylate), and poly(ethylene phthalate‐co‐ethylene 2,6‐naphthalene dicarboxylate)
Authors: Iijima Takao , Ono Hiroshi , Tomoi Masao
Published: September 2002

Aromatic polyesters were prepared and used to improve the brittleness of bismaleimide resin, composed of 4,4′‐bismaleimidodiphenyl methane and o,o′‐diallyl bisphenol A (Matrimid 5292 A/B resin). The aromatic polyesters included PEPT [poly(ethylene phthalate‐co‐ethylene terephthalate)], with 50 mol % of terephthalate, PEPB [poly(ethylene phthalate‐co‐ethylene 4,4′‐biphenyl dicarboxylate)], with 50 mol % of 4,4′‐biphenyl dicarboxylate, and PEPN [poly(ethylene phthalate‐co‐ethylene 2,6‐naphthalene dicarboxylate)], with 50 mol % 2,6‐naphthalene dicarboxylate unit. The polyesters were effective modifiers for improving the brittleness of the bismaleimide resin. For example, inclusion of 15 wt % PEPT (MW = 9300) led to a 75% increase in fracture toughness, with retention in flexural properties and a slight loss of the glass‐transition temperature, compared with the mechanical and thermal properties of the unmodified cured bismaleimide resin. Microstructures of the modified resins were examined by scanning electron microscopy and dynamic viscoelastic analysis. The toughening mechanism was assessed as it related to the morphological and dynamic viscoelastic behaviors of the modified bismaleimide resin system. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2352–2367, 2001
Comparative study of the tribological properties of polyamide 6 filled with molybdenum disulfide and liquid crystalline additives
Authors: Bermúdez M. D. , Carrión‐Vilches F. J. , Martínez‐Mateo I. , Martínez‐Nicolás G.
Published: September 2002

The effect of adding a 1 wt % proportion of thermotropic liquid crystals 4,4′‐dibutylazobenzene (LC1) and 4‐octyl, 4′‐cyanobiphenyl (LC2) on the tribological properties of polyamide 6 (PA 6) is compared with that of the addition of MoS2 in different concentrations (1 and 5 wt %). Friction and wear are determined in a pin‐on‐disk tribometer by using injection‐molded additivated nylon disks against steel or aluminum pins, below (25°C) and above (80°C) glass transition temperature. Polymeric blends are characterized by differential scanning calorimetry and by optical and scanning electron microscopy and microanalysis. Concentration of liquid crystalline additives is higher at the surface than in the bulk of PA 6 disks. Crystallinity degree of PA‐6 is not significantly changed by the presence of additives. Addition of 1 wt % LC1 improves processibility of PA 6 by increasing its melt flow rate. Cyanoderivative liquid crystal (LC2) shows the best wear‐reducing ability for PA 6/steel contacts at all temperatures. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2426–2432, 2001
Thermal, thermomechanical, and electrochemical characterization of the organic–inorganic hybrids poly(ethylene oxide) (PEO)–silica and PEO–silica–LiClO4
Authors: Kweon Jung‐Ohk , Noh Si‐Tae
Published: September 2002

To study the effect of the silica content on the properties of the salt‐free and salt‐added hybrids based on poly(ethylene oxide) (PEO) and silica, two series of hybrids, PEO–silica and PEO–silica–LiClO4 (O:Li, 9:1) hybrids were prepared via the in situ acid‐catalyzed sol–gel reactions of the precursors [i.e., PEO functionalized with triethoxysilane and tetraethyl orthosilicate (TEOS)]. The morphology of the hybrids was examined by scanning electron microscopy (SEM) of the fracture surfaces of the hybrid. The results indicated that the discontinuity develops with increasing the weight percent of silica in both hybrids. The differential scanning calorimetric (DSC) analysis indicated that effects of silica content on the glass transition temperatures (Tg) of the PEO phase were different in salt‐free and salt‐added hybrids. The Tg of PEO phase increased with increasing weight percent of silica in salt‐free hybrids, whereas the curve of Tg of PEO phase and silica content had a maximum at 35 wt % of silica content in salt‐added hybrids. For both salt‐free and salt‐added hybrids, peaks of the loss tangent, determined by dynamic mechanical analysis (DMA) were gradually broadened and lowered with increasing weight percent of silica. The storage modulus, E′, in the region above Tg increases with increasing silica content for both PEO–silica and PEO–silica–LiClO4 hybrids. In the conductivity and composition curves for PEO–silica–LiClO4 hybrids, the conductivity shows a maximum value of 3.7 × 10−6 S/cm, corresponding to the sample with a 35 wt % of silica. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2471–2479, 2001
Structure/rheological properties relations of crosslinked potato starch suspensions
Authors: Dubois I. , Picton L. , Muller G. , Audibert‐Hayet A. , Doublier J. L.
Published: September 2002

Some rheological properties of aqueous suspensions of crosslinked hydroxypropylated potato starches were investigated. The crosslinking was performed at a temperature above the gelatinization temperature and the degree of crosslinking varied between 0.05 and 0.75% wt. The samples were characterized by the swelling power Q and the average particle size D and observed by light microscopy and low‐temperature SEM. The swelling power decreases with the extent of crosslinking, whereas the average particle size increases. From these observations, the starch samples can be described as suspensions of deformable particles suspended in a continuous suspending medium constituted of polymer chains plus water. The rheological properties allow us to define different concentration regimes depending on the close packing of swollen particles at a concentration C*, which is close to 1/Q. In dilute conditions, that is, for C < C*, the viscosity is little influenced by the degree of crosslinking and, hence, by the particle size. Two domains can be defined: a “true dilute” one for C < 0.6C* and a semidilute one for C > 0.6C*, in which the viscosity rapidly increases with the concentration. Moreover, an apparent yield stress and elastic properties are observed in the concentrated regime, for C > C*. Two domains can be also defined: a first one for C < 2C*, in which the rheological characteristics sharply increase with the concentration, and a second one, a quasi‐plateau domain, for C > 2C*. The variations of these rheological properties suggest that the rigidity of the swollen particles can be considered, contrary to the viscosity in the true dilute regime. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2480–2489, 2001
Dynamic mechanical properties of polyimide/poly(silsesquioxane)‐like hybrid films
Authors: Tsai Mei‐Hui , Whang Wha‐Tzong
Published: September 2002

Polyimide/poly(silsesquioxane)‐like (PI/PSSQ‐like) films have three‐dimensional structure with linear PI blocks and a crosslinked PSSQ‐like structure. They have higher thermal stability and char yields than pure PI from 4,4′‐diaminodiphenyl ether and 3, 3′‐oxydiphthalic anhydride (ODPA). In a series of X‐PIS [PI modified with p‐aminophenyltrimethoxysilane (APTS), where X is the molecular weight of each PI block] hybrid films, decreasing the PI block chain length enhances the storage modulus, tensile modulus, and glass‐transition temperature (Tg) but reduces the α‐relaxation damping peak intensity, density, and elongation. The change in the former three properties may be caused by an increase in the crosslinking density and rigidity of the network structure. The changes in the next two properties are caused by an increase in the free volume or the PI interblock separation and decreases in the interblock PI chain interaction. The change in the last property (i.e., a decrease in elongation) is related to the increase in the rigidity of the network structure. The activation energy of the α transition depends on the chain length of the PI block. A maximum value is reached at the chain length of 10,000 because of two different factors: crosslinking density and free volume. In a series of X‐PIS‐y‐PTS [X‐PIS modified with phenyltrimethoxysilane (PTS), where y is the weight‐ratio percentage of PTS to APTS–polyamic acid] films with a constant PI block length, the storage modulus, tensile modulus, Tg, density, and α‐relaxation damping peak intensity decrease with the PTS content. This could be because of the increase of the PSSQ‐like domain size with the PTS content, which leads to the introduction of more free volume or interblock separation and to a decrease in the interblock chain interaction force. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2500–2516, 2001
Preparation and characterization of conducting polymer coating on ABS substrate
Authors: Patil R. C. , Aoyanagi T. , Nakayama M. , Ogura K.
Published: September 2002

Conducting polymer coatings on ABS were prepared by dipping them into m‐cresol solutions containing polyaniline (PANI), poly(o‐toluidine) (POT), and poly(o‐anisidine) (PoAN) protonated with dioctyl hydrogen phosphate (DiOHP) in the presence and absence of polystyrene (PS). The surface resistivity of ABS plates coated with DiOHP‐doped PANI in the presence and absence of PS were 5.3 × 107 and 3.0 × 105 Ω, respectively. The ABS plates coated with DiOHP‐doped PoAN and ‐doped POT showed higher resistivities (4.2 × 109 and 2.4 × 107 Ω, respectively) than that with DiOHP‐doped PANI. Although the conductivity of the coated ABS with DiOHP‐doped PANI was less in the presence of PS, the permanency and uniformity of the coating, which are very important for practical use, were much improved. Coatings and the coated ABS were characterized by X‐ray diffraction, TG/MS, SEM, and reduced viscosity measurements. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2661–2669, 2001
Rheological properties of syndiotacticity‐rich ultrahigh molecular weight poly(vinyl alcohol) dilute solution
Authors: Choi Jin Hyun , Lyoo Won Seok , Ko Sohk Won
Published: September 2002

Viscoelastic behavior of the dilute solution of ultrahigh molecular weight syndiotactic poly(vinyl alcohol) (UHMW s‐PVA)/dimethyl sulfoxide (DMSO)/water was investigated through rheological response. Below a critical temperature, the dynamic storage modulus (G′) of the solution became greater than the dynamic loss modulus (G″) and the viscoelastic exponent for G′ became smaller than that for G″ before macroscopic gelation, which indicates the evolution of viscoelastic solid properties at the sol state. Also, the loss tangent (tan δ) of the solution below the critical temperature increased with increasing frequency. Consequently, the dilute solution of UHMW s‐PVA/DMSO/water showed the rheological behaviors as can be observed in general chemical or physical gel systems below the critical temperature. These results suggest that solid‐like heterogeneity prevailed in the solution before macroscopic gelation with decreasing temperature. Such heterogeneity was considered as phase‐separated domains attributed to spinodal decomposition. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 569–576, 2001
Application of chemo‐rheology to establish a process window for a new solventless system to manufacture pre‐pregs and laminates for electronic applications
Authors: Dehnke L. M. , Permadi  , Castro J. M.
Published: September 2002

The most common commercial processes for manufacturing pre‐pregs for electronic applications use solvent‐based epoxy systems. Solvents are environmentally unfriendly and contribute to voids in the pre‐preg and laminate. Voids cause product variability, which is a major source of scrap in board shops. In this paper, we use chemo‐rheological and kinetic measurements to identify a potential epoxy‐based resin system for a solventless process that is based on injection pultrusion. Differential scanning calorimetry and rheological data show that the candidate system does not react appreciably without catalyst up to temperatures of 170 °C or with catalyst at temperatures <110 °C. The system solidifies at temperatures <105 °C. The overall viscosity of the resin system is dependent on the temperature, degree of cure, and filler content. Kinetic rate and viscosity rise expressions to be used in process modeling and optimization have been developed. A preliminary process window for the process is established. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 601–610, 2001
Immiscible ethylene vinyl acetate and nylon blends processed below nylon melting temperature
Authors: Tzur A. , Narkis M. , Siegmann A.
Published: September 2002

This article focuses on unique compounding and processing conditions at a temperature slightly below the melting temperature of the dispersed phase and well above the melting peak temperature of the matrix. Compounding and processing were carried out at the same temperature. Fibrillar morphologies were obtained by blending ethylene vinyl acetate (EVA) copolymer with nylon 6 (N6) and compounding and processing them slightly below the N6 melting temperature. A hot, soft‐solid particle drawing mechanism that operates in such processing conditions caused fibrillation of the N6 particles and formation of highly oriented fibril‐filled composites throughout the entire volume. Morphological observations were made in the core region. Enhancement of some mechanical properties and interesting morphological structures were found in some of the blends. The melt elasticity, which was measured by the die swell of the filaments, was maximum at a temperature slightly below the N6 melting temperature, which supported the concept of fibrillation by processing it slightly below the melting temperature of the dispersed phase. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 661–671, 2001
Copolymerization of ethylene and 1‐octene by homogeneous and different supported metallocenic catalysts
Authors: De Fátima Vieira Marques Maria , Conte Anunciata , De Resende Flávia C. , Gervasoni Chaves Érica
Published: September 2002

In this work, the performance of the homogeneous catalyst system based on Et(Flu)2ZrCl2/MAO was evaluated on the copolymerization of ethylene and 1‐octene. Characteristics of some of the produced polymers were also investigated. A study was performed to compare this system with that of Cp2ZrCl2/MAO. The influence of different support materials for the Cp2ZrCl2 was also evaluated, using silica, MgCl2, and the zeolite sodic mordenite NaM. An increase in activity was observed in relation to the comonomer addition for the two homogeneous catalysts. The copolymers produced by the Et(Flu)2ZrCl2/MAO system showed higher molecular weight and narrower molecular weight distribution. We verified that the catalyst supported on SiO2 was the most active one, although the copolymers produced with the catalyst supported on NaM showed higher molecular weight and lower molecular weight distribution. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 724–730, 2001
Effect of co‐promoter and secondary monomer on shrinkage control of unsaturated polyester (UP)/styrene (St)/low‐profile additive (LPA) systems cured at low temperatures
Authors: Cao Xia , Lee L. James
Published: September 2002

The shrinkage of unsaturated polyester (UP)/styrene (St) resins cured at low temperatures can be reduced by the presence of low‐profile additives (LPAs). It is believed that the reaction‐induced phase separation and the polymerization shrinkage in both the LPA‐rich and UP‐rich phases result in the formation of microvoids, which partially compensates the resin shrinkage. The relative reaction rate in the two phases plays an important role in shrinkage control. In this study, secondary monomers [such as divinylbenzene (DVB) and trimethylopropane trimethacrylate (TMPTMA)] and a co‐promoter, 2,4‐pentandione (2,4‐P), were added into the UP/St/LPA resin systems to investigate their effect on the shrinkage control of resins cured at low temperatures. Dilatometery results showed that the addition of both TMPTMA and 2,4‐P resulted in an earlier volume expansion during curing and better shrinkage control. The phase separation, reaction kinetics, and viscosity changes in the LPA‐rich and UP‐rich phases during curing were also investigated. The results confirmed that the increased reaction rate in the LPA‐rich phase led to an earlier formation of microvoids and, consequently, less volume shrinkage of the cured resin. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 738–749, 2001
Synthesis and melt spinning of fully aromatic thermotropic liquid crystalline copolyesters containing m‐hydroxybenzoic acid units
Authors: Yerli̇kaya Zekeri̇ya , Aksoy Serpi̇l , Bayramli Erdal
Published: September 2002

Fibers of fully aromatic thermotropic copolyesters based on p‐acetoxybenzoic acid (p‐ABA), hydroquinone diacetate (HQDA), terephthalic acid (TPA), and m‐acetoxybenzoic acid (m‐ABA) were prepared by a high‐temperature melt‐spinning technique. Two types of the copolyesters were prepared by a high‐temperature melt polycondensation reaction using 33 mol % of kink (m‐ABA) and 67 mol % linear monomer units (p‐ABA, TPA, HQDA), and characterized by differential scanning calorimetry (DSC), polarized optical microscopy, wide‐angle X‐ray diffraction (WAXD), and intrinsic viscosity measurements. The mechanical properties and the morphology of the fibers were also determined by tensile tester, WAXD, and scanning electron microscopy (SEM). The copolyesters exhibited phase‐separated nematic liquid crystalline morphology within a broad temperature range in an isotropic matrix. DSC analysis of the copolyesters revealed broad endotherms associated with the nematic phases. The melting and spinning temperatures were in a processable region. Fibers exhibit well‐developed fibrillar structure parallel to the fiber axis. The highly oriented morphology of the fibrils is slightly dependent on the type of the linear monomer. The strength and modulus values determined for the fibers that contain equal molar composition of the linear p‐ABA, HQDA/TPA units are comparable to other reported rigid systems containing fully aromatic species. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 2580–2587, 2002
Original histologic findings in arteries of the right ventricle papillary muscles in human hearts
Authors: Nerantzis Christos E. , Koutsaftis Philip N. , Marianou Soultana K. , Karakoukis Nikolaos G. , Cafiris Nikolaos A. , Kontogeorgos George
Published: September 2002

In this study we describe original histologic findings of the right ventricle papillary muscle (PM) arteries in people under 30 years old. We examined 666 samples taken from the tip, mid‐portion, and base of the PM in 56 males and 55 females, as well as samples from the rest of the right ventricle. The amount of smooth muscle cell (SMC) fibers in the tunica media (TM) led to their division into three groups: Group 1: 351 samples (53%); normal amount, normal lumen. The amount of SMCs increased from the tip (20%) to the base (48%). Group 2: 226 samples (34%); mild to moderately increased amount of SMCs, with narrowness, eccentric displacement, and uneven lumen shape. They decreased from the tip (42%) to the base (23%). Group 3: 89 samples (13%), with abundant SMCs that duplicated the arterial size, contrary to the other two groups. Their shape was round and their extremely narrow, centrally located lumen had a round or oval shape. These changes were restricted only to PM arteries and decreased from the tip (65%) to the mid‐portion (35%). This type of artery predominated compared to the other two groups, probably because of the narrow lumen. No inflammatory reaction or chronic ischemic changes were found in the PM and its arteries. The SMC changes in groups 2 and 3 were found in subjects older than 2 months. The above findings will provide anatomists, cardiologists, and physiologists with valuable knowledge. Anat Rec 266:146–151, 2002. © 2002 Wiley‐Liss, Inc.
Morphologic changes in the TMJ following splint wear
Authors: Sindelar Betty J. , Edwards Stan , Herring Susan W.
Published: September 2002

Intraoral splints are a commonly used dental treatment for a variety of conditions. Because such splints alter the condyle–disc–fossa relationship, they probably change the loading status of the temporomandibular joint (TMJ), including the TMJ disc. Collagen, a major constituent of the disc, acts to resist tensile loading, and it is presumed that the fiber orientations of the individual disc bands reflect their functional loading. Therefore, the purpose of this study was to examine effects of intraoral splint wear on TMJ morphology in general, and collagen orientation of the intra‐articular disc in particular. Young adult, female miniature pigs were divided into three groups: open‐bite splint, protrusive‐bite splint, and unsplinted control. Splints were worn for 2 months, after which the TMJ discs were harvested for histological examination and stereological analysis, and the skulls were cleaned. Although the splints had no effect on skull dimensions, changes were seen in the TMJs. The discs of the protrusively‐splinted group showed an increased thickness of the posterior band (P < 0.015) and minor changes in collagen orientation of the anterior band. The most striking change was the presence of a degenerative osseous defect on the medial side of the mandibular condyle in half of the splinted animals. These results indicate that prolonged splint wear can induce remodeling and even injury of TMJ tissues. Anat Rec 266:167–176, 2002. © 2002 Wiley‐Liss, Inc.
Bony orbital anatomy of the koala (Phascolarctos cinereus)
Authors: Kempster R.C. , Hirst L.W.
Published: September 2002

This is the first documented study of the anatomical details of the normal koala orbit. Baseline data are established which are necessary for understanding and treating ocular disease in the koala (Phascolarctos cinereus). The bony anatomy of the orbit of the koala was examined and described from animals that presented dead or had been euthanized for humane reasons. Dissections of the orbital cavity were performed under magnification, and descriptions of the orbital bones were from macerated skulls that had been boiled and cleaned. In general, the orbital bones of the koala, and their respective foramina, are consistent with those of other carnivorous polyprotodont and herbivorous diprotodont marsupials. Anat Rec 267:288–291, 2002. © 2002 Wiley‐Liss, Inc.
Development of a CENP‐A/CENP‐B–specific immune response in a patient with systemic sclerosis
Authors: Mahler Michael , Mierau Rudolf , Genth Ekkehard , Blüthner Martin
Published: September 2002

Antibodies directed against an epitope motif on CENP‐A have been shown to cross‐react with mimotopes on other autoantigens and on Epstein‐Barr nuclear antigen 1 (EBNA‐1), suggesting a molecular mimicry. We describe here the gradual development of an anticentromere immune response in a patient with systemic sclerosis, which started from an antihistone response and was not mediated by molecular mimicry. Via an epitope on histone H3, the antibody response spread to a homologous epitope in the H3 homology domain of CENP‐A. This was followed by an intramolecular epitope spreading to N‐terminal peptides of CENP‐A containing the known epitope motif G‐P‐X1‐R‐X2. From there it spread to corresponding epitopes on CENP‐B and to mimotopes of the major CENP‐A epitope motif on other autoantigens including EBNA‐1. Whether the D‐penicillamine treatment received by this patient was involved in the triggering of this cascade remains a matter of speculation.
Cyclooxygenase 2‐dependent prostaglandin E2 modulates cartilage proteoglycan degradation in human osteoarthritis explants
Authors: Hardy Medora M. , Seibert Karen , Manning Pamela T. , Currie Mark G. , Woerner B. Mark , Edwards Dorothy , Koki Alane , Tripp Catherine S.
Published: September 2002

Objective

To examine cyclooxygenase‐2 (COX‐2) enzyme expression, its regulation by interleukin‐1β (IL‐1β), and the role of prostaglandin E2 (PGE2) in proteoglycan degradation in human osteoarthritic (OA) cartilage.

Methods

Samples of human OA articular cartilage, meniscus, synovial membrane, and osteophytic fibrocartilage were obtained at knee arthroplasty and cultured ex vivo with or without IL‐1β and COX inhibitors. COX expression was evaluated by immunohistochemistry and Western blot analysis. The enzymatic activity of COX was measured by conversion of arachidonic acid to PGE2. Cartilage degradation was evaluated by measuring the accumulation of sulfated glycosaminoglycans in the medium.

Results

IL‐1β induced robust expression of COX‐2 and PGE2 in OA meniscus, synovial membrane, and osteophytic fibrocartilage explants, whereas low levels were produced in OA articular cartilage. IL‐1β also induced cartilage proteoglycan degradation in OA synovial membrane‐cartilage cocultures. Increased proteoglycan degradation corresponded to the induction of COX‐2 protein expression in, and PGE2 production from, the synovial membrane. Dexamethasone, neutralizing IL‐1β antibody, or the selective COX‐2 inhibitor, SC‐236, attenuated both the IL‐1β‐induced PGE2 production and cartilage proteoglycan degradation in these cocultures. The addition of PGE2 reversed the inhibition of proteoglycan degradation caused by SC‐236.

Conclusion

IL‐1β‐induced production of COX‐2 protein and PGE2 was low in OA articular cartilage compared with that in the other OA tissues examined. IL‐1β‐mediated degradation of cartilage proteoglycans in OA synovial membrane‐cartilage cocultures was blocked by the selective COX‐2 inhibitor, SC‐236, and the effect of SC‐236 was reversed by the addition of exogenous PGE2. Our data suggest that induction of synovial COX‐2‐produced PGE2 is one mechanism by which IL‐1β modulates cartilage proteoglycan degradation in OA.
Kinetics of bone protection by recombinant osteoprotegerin therapy in Lewis rats with adjuvant arthritis
Authors: Campagnuolo Giuseppe , Bolon Brad , Feige Ulrich
Published: September 2002

Objective

To assess the effect of different dosages and treatment schedules of osteoprotegerin (OPG) on joint preservation in an experimental model of adjuvant‐induced arthritis (AIA).

Methods

Male Lewis rats with AIA (6–8 per group) were treated with a subcutaneous bolus of recombinant human OPG according to one of the following schedules: daily OPG (an efficacious regimen) starting at disease onset (days 9–15), early intervention (days 9–11), delayed intervention (days 13–15), and extended therapy (days 9–22). Inflammation (hind paw swelling) was quantified throughout the clinical course; osteoporosis (bone mineral density [BMD], by quantitative dual x‐ray absorptiometry) and morphologic appraisals of inflammation, bone damage, intralesional osteoclasts (by semiquantitative histopathologic scoring), and integrity of the articular cartilage matrix (by retention of toluidine blue stain) were determined in histology sections of arthritic hind paws.

Results

OPG provided dose‐ and schedule‐dependent preservation of BMD and periarticular bone while essentially eliminating intralesional osteoclasts. Dosages ≥2.5 mg/kg/day preserved or enhanced BMD and prevented essentially all erosions. A dosage of 4 mg/kg/day protected joint integrity to a comparable degree when given for 7 (days 9–15) or 14 (days 9–22) consecutive days. At this dosage, early intervention (days 9–11) was twice as effective as delayed intervention (days 13–15) at preventing joint dissolution. Erosions and osteoclast scores were greatly decreased for 26 days (measured from the first treatment) after 7 or 14 daily doses of OPG (4 mg/kg/day). OPG treatment also prevented loss of cartilage matrix proteoglycans, an indirect consequence of protecting the subchondral bone. No OPG dosage or regimen alleviated weight loss, inflammation, or periosteal osteophyte production.

Conclusion

These data indicate that OPG preserves articular bone and (indirectly) articular cartilage in arthritic joints in a dose‐ and schedule‐dependent manner, halts bone erosion when given at any point during the course of arthritis, produces sustained antierosive activity after a short course, and is most effective when initiated early in the disease.
High levels of osteoprotegerin and soluble receptor activator of nuclear factor κB ligand in serum of rheumatoid arthritis patients and their normalization after anti–tumor necrosis factor α treatment
Authors: Ziolkowska Maria , Kurowska Mariola , Radzikowska Anna , Luszczykiewicz Grazyna , Wiland Piotr , Dziewczopolski Wojciech , Filipowicz‐Sosnowska Anna , Pazdur Jacek , Szechinski Jacek , Kowalczewski Jacek , Rell‐Bakalarska Maria , Maslinski Wlodzimierz
Published: September 2002

Objective

To test the hypotheses that 1) proinflammatory cytokines affect osteoprotegerin (OPG) and soluble receptor activator of nuclear factor κB ligand (sRANKL) production and therefore the OPG and sRANKL levels differ in rheumatoid arthritis (RA) patients in comparison with healthy individuals; and 2) anti–tumor necrosis factor α (anti–TNFα) therapy influences OPG and sRANKL levels.

Methods

Sera were obtained from healthy individuals or RA patients receiving the combination of infliximab and methotrexate. Peripheral blood mononuclear cells (PBMCs) and synovial fluid mononuclear cells (SFMCs) were isolated from RA patients. Fibroblast‐like synoviocytes (FLS) were isolated from synovial tissue obtained at total knee replacement in RA patients. Supernatants from cells stimulated with cytokines were collected after culture in vitro. Concentrations of OPG and sRANKL were determined by enzyme‐linked immunosorbent assays.

Results

A strong positive correlation between OPG concentration and age was observed in healthy individuals but not in RA patients. The OPG and sRANKL levels were higher in RA patients than in healthy controls. Cultured FLS spontaneously secreted much higher amounts of OPG than PBMCs or SFMCs. Proinflammatory cytokines enhanced OPG production. Anti‐TNFα treatment resulted in the normalization of serum OPG and sRANKL levels in RA patients without influencing the OPG:sRANKL ratio.

Conclusion

Although higher serum levels of OPG and sRANKL are present in RA patients than in healthy individuals, the ratio of OPG:sRANKL is similar. There is an age‐dependent increase of OPG but not sRANKL levels in healthy subjects. Anti‐TNFα treatment results in the normalization of elevated levels of OPG and sRANKL in RA patients.
Avascular necrosis of the femoral head in a patient with Fabry's disease: Identification of ceramide trihexoside in the bone by delayed‐extraction matrix‐assisted laser desorption ionization–time‐of‐flight mass spectrometry
Authors: Horiuchi Hiroshi , Saito Naoto , Kobayashi Seneki , Ota Hiroyoshi , Taketomi Tamotsu , Takaoka Kunio
Published: September 2002

Fabry's disease is a lipid storage disease caused by an X‐linked hereditary deficiency of α‐galactosidase. The enzymatic defect causes progressive deposition of ceramide trihexoside (CTH) in various tissues, leading to renal failure, premature myocardial infarction, and stroke, with a high rate of mortality in younger patients. Among the complications associated with Fabry's disease, a few cases involving avascular necrosis (AVN) of the femoral head have been reported. However, direct evidence of deposition of CTH in bone marrow in the femoral head has not been demonstrated. This report describes a 58‐year‐old man who underwent total hip arthroplasty for femoral head AVN associated with Fabry's disease. The accumulation of CTH was examined by chemical analysis of the sphingolipid extracted from the femoral head, using delayed‐extraction matrix‐assisted laser desorption ionization–time‐of‐flight mass spectrometry. This is the first report confirming the presence of CTH in the sphingolipid fraction from normal and necrotic bone of a patient with Fabry's disease.