bluuebunny/crossref_metadata_2025_split huggingface dataset:
Novel homoplasmic mutation in the mitochondrial tRNATyr gene associated with atypical mitochondrial cytopathy presenting with focal segmental glomerulosclerosis
Authors: Scaglia Fernando , Vogel Hannes , Hawkins Edith P. , Vladutiu Georgirene D. , Liu Ling‐Ling , Wong Lee‐Jun C. 
Published: October 2003

AbstractWe report a 9‐year‐old girl with a mitochondrial cytopathy preceded by steroid‐resistant focal segmental glomerulosclerosis (FSGS). The proband presented at the age of 2 years with steroid‐resistant nephrotic syndrome caused by FSGS. Her renal function progressively deteriorated and a dilated cardiomyopathy developed at the age of 7 years. A skeletal muscle biopsy showed a combined respiratory chain (RC) defect and a partial deficiency of coenzyme Q10. A novel mutation in the evolutionary highly conserved region of the mitochondrial tRNATyr gene was found in homoplasmic state in skeletal muscle, blood, and renal tissue. The mutation was also found in homoplasmic state in her mildly symptomatic mother. No other maternal family members were available for testing. The present case of mitochondrial cytopathy initially presenting with steroid‐resistant nephrotic syndrome, unusual biochemical and renal findings associated with a novel tRNA point mutation suggests that steroid‐resistant FSGS can predate other features of mitochondrial disease for a prolonged period of time and that the progressive glomerulopathy associated with combined mitochondrial RC defects is genetically heterogeneous. © 2003 Wiley‐Liss, Inc.
Stress development in drying fibers and spheres
Authors: Lei Herong , Francis Lorraine F. , Gerberich William W. , Scriven L. E. 
Published: October 2003

AbstractStress development during drying is a critical factor that affects the final structure and properties of a coated fiber or spherical product. Stress development during drying of the coating is due to nonuniform shrinkage and physical constraints. In this study, a large deformation elasto‐viscoplastic model is developed to predict stress development in drying fibers and spheres after the coatings solidify. From the model, stress evolution in the drying fibers/spheres can be predicted by a partial differential equation of diffusion in one dimension, a first‐order partial differential equation of pressure distribution, and two ordinary differential equations on local evolution of the stress‐free state. The system of equations is solved by the Galerkin/finite element method in the one dimensional axial/spherical symmetric coatings. Solutions show changes in solvent concentration and viscous stress as the coating dries. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 3934–3944, 2003
Deformation, yield and fracture of elastomer‐modified polypropylene
Authors: Zebarjad S. M. , Bagheri R. , Reihani S. M. Seyed , Lazzeri A. 
Published: October 2003

AbstractIn recent decades, great attention has been devoted to the toughening of isotactic poly(propylene) (PP) with elastomers such as ethylene–propylene rubber (EPR). The most important reasons for this interest are the moderate cost and favorable properties of PP. This article is focused on the role of EPR in the deformation and fracture mechanism of PP/EPR blends with different volume fractions of elastomer phase. Differential scanning calorimetry (DSC), tensile tests, and microscopy techniques were used in this study. The fracture mechanism of isotactic PP toughened by EPR (PP/EPR) has also been studied by three point bending (3‐PB) and four point bending (4‐PB) tests. Rubber particle cavitation appears to be the main mechanism of microvoid formation, although some matrix/particle debonding was observed. The investigation of the toughening mechanism shows that a wide damage zone spreads in front of the pre‐crack. Optical microscopy (OM) illustrates that, in pure PP, crazing is the only fracture mechanism, and no evidence of shear yielding is found, while in PP blends craze‐like features associated with shear yielding are observed, which have been identified as high shear localized dilatational bands. This type of deformation pattern supports a model previously proposed by Lazzeri1 to explain the interparticle distance effect on the basis of the stabilization effect on dilatational band propagation exerted by stretched rubber particles. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 3767–3779, 2003
Silicone elastomers for electronic applications. II. Effects of noncrosslinked materials
Authors: Andersson L. H. U. , Johander P. , Hjertberg T. 
Published: October 2003

AbstractWe performed applied functional tests to examine how the noncrosslinked fraction of a cured silicone elastomer affected the performance of electrical devices and the solderability and adhesion on gold‐plated printed circuit boards. To obtain information about the spreading tendencies of commercial silicone elastomers, and to complement the function tests, we conducted so‐called creep tests to examine the migration and spreading of the noncrosslinked fraction. The electrical tests, performed with both reference oligomers and cured commercial poly(dimethyl siloxane)s, showed that failure occurred even at very low silicone contamination levels. The solderability and adhesion, however, were not affected by the presence of poly(dimethyl siloxane)s, especially not the reference solutions, which consisted mainly of volatile siloxanes. The creep tests, performed on commercial silicone elastomers, indicated that the noncrosslinked, nonvolatile part had to be taken into account in a discussion of silicone contamination. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 3780–3789, 2003
Preparation and properties of water‐resistant soy dreg/benzyl konjac glucomannan composite plastics
Authors: Chen Yun , Zhang Lina , Lu Yongshang , Ye Changsheng , Du Libo 
Published: October 2003

AbstractABTSRACT:Biodegradable plastics based on soy dreg (SD) were prepared with glycerol as a plasticizer via compression molding at 110–160°C. The effects of the glycerol content and molding temperature on the processability and mechanical properties were investigated. For enhanced water resistivity of the SD plastics, thermoplastic benzyl konjac glucomannan (B‐KGM) films were covered on SD sheets in a lamination compression process, and SD/B‐KGM (SB) composite sheets were obtained. The structure and properties of the SB sheets were studied with Fourier transform infrared spectroscopy, dynamic mechanical thermal analysis (DMTA), scanning electron microscopy, and tensile testing. The results indicated that the tensile strength of the SB sheets was enhanced to 13.2 MPa in the dry state and to 11.4 MPa in the wet state. The water resistivity of the SB sheets with B‐KGM covers increased from 0.03 to 0.86 with an increase in the B‐KGM thickness from 0 to 35 μm. The multipeaks of a tan δ relaxation that appeared in the DMTA spectra for SB series sheets were due to multicomponents such as soy protein, cellulose, polysaccharide, and B‐KGM. The tan δ transition temperature and the decomposition temperature of cellulose in SB sheets were higher than those in SD sheets without B‐KGM covers. This work provided a simple way of improving the compression‐molding processability and water resistivity of SD plastics for practical applications. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 3790–3796, 2003
Cure modification of natural rubber containing benzothiazole accelerators by some modified thiocarbamyl sulfenamides
Authors: Datta R. N. , Debnath S. C. , Noordermeer J. W. M. 
Published: October 2003

AbstractThe effects of N‐cyclopentamethylene thiocarbamyl‐N′‐(cyclohexyl,thiocyclohexyl)sulfenamide (CPCTS) and N‐oxydiethylene thiocarbamyl‐N′‐(cyclohexyl,thiocyclohexyl)sulfenamide (ODCTS) as cure modifiers on the vulcanization of natural rubber (NR) containing benzothiazole accelerators were studied. CPCTS and ODCTS were used separately with 2‐mercaptobenzothiazole and N‐oxydiethylene benzothiazole sulfenamide to determine their effects on these accelerators. CPCTS and ODCTS retarded the accelerators. Enhanced activity was found with respect to the torque, scorch, modulus, and tensile strength and was believed to be due to the formation of different intermediate components during the early stage of the vulcanization of NR. Reactions likely responsible for acceleration and retardation were explored. CPCTS and ODCTS provided better cure retardation than N‐cyclohexyl thiophthalimide. The chemical characterization of the NR vulcanizates correlated with the physical properties obtained at 140°C. Stocks containing CPCTS or ODCTS produced mostly monosulfide linkages, which were affected when N‐cyclohexyl thiophthalimide was used. This provided information concerning the heat‐resistance properties of the vulcanizates. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 3835–3847, 2003
Interfacial tension measurements and evidence of order in high‐density polyethylene melts
Authors: Chan Colleen C. V. , Elliott Janet A. W. , Williams Michael C. 
Published: October 2003

AbstractPolyethylene (PE) is a widely used product commercially. However, our knowledge is incomplete about the properties of high‐density polyethylene (HDPE) at temperatures above its melting point, where solid crystals disappear. Recently, there has been increasing evidence from rheological, differential scanning calorimetry, and NMR studies that suggests the presence of microstructural order in the bulk of PE melts. In this study, the interfacial tension of HDPE melts in contact with silicone oil was measured with a spinning drop tensiometer in the same temperature range in which phase transitions have been observed in the bulk HDPE. Anomalous temperature dependence of interfacial tension was found between 200 and 230°C. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 4061–4067, 2003
Synthesis, characterization, and blood compatibility of copolymers of polyamidoamines and n‐vinylpyrrolidone
Authors: Kumar Dey Ratan , Ray Alok R. 
Published: October 2003

AbstractTwo new polyamidoamines derived from piperazine (Pip)/cyclohexylamine (CHA) and N,N′‐methylene bisacrylamide (MBA) were synthesized and subsequently copolymerized with N‐vinylpyrrolidone (NVP) under suitable reaction conditions to yield the respective copolymers (Pip–MBA–NVP and CHA–MBA–NVP). The synthesized materials were characterized by spectroscopic techniques. The material surface characteristics were checked by contact angle measurement, and the data established the relative hydrophilic characteristics of the synthesized copolymers with respect to the control poly(N‐vinylpyrrolidone). A thrombus‐formation study indicated less (<1.2 mg) clot formation on the heparinized material surfaces within a 30‐min contact time with the acid citrate dextrose human blood. The percentage of hemolysis of the blood by the materials was also less than 5%. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 4068–4074, 2003
New method of dyeing keratin fibers using poly(ethylene imine) and its coloring mechanism
Authors: Kuzuhara A. , Hori T. 
Published: October 2003

AbstractTo improve the colorability of keratin fibers at lower temperatures, we developed a novel coloring method using poly(ethylene imine) (PEI) as a counterion reagent (human hair was treated beforehand with a PEI solution and then was colored with an acid dye). As a result of this new method, the coloring and color fastness to shampooing clearly improved with respect to the usual method. Next, to study the coloring mechanism with PEI, we investigated the penetration of PEI and Orange II into bleached human hair by optical microscopy. The results showed that the penetration of PEI and Orange II into bleached human hair increased with an increasing PEI treatment time and with a decreasing PEI molecular weight. With these experiments, we demonstrated that PEI, which penetrated the cortex region, exerted counterionization on Orange II, thereby increasing the penetration of Orange II into bleached human hair. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 3806–3810, 2003
Study on the synthesis, characterization, and sorption of some metal ions on gelatin‐ and acrylamide‐based hydrogels
Authors: Chauhan Ghanshyam S. , Kumar Suresh , Kumari Anita , Sharma Rakesh 
Published: October 2003

AbstractGraft copolymers and networks of gelatin were synthesized with three acrylamides (acrylamide, 2‐acrylamido‐2‐methyl‐1‐propanesulfonic acid, and N‐iso‐propylacrylamide) by using a redox initiator system consisting of ammonium peroxysulfate–ferrous ammonium sulfate in either the absence or the presence of a crosslinker (N,N‐methylene bisacrylamide) at two temperatures. Characterization of synthesized polymers was studied by FTIR and thermal studies to investigate evidence of grafting or interpenetrating network formation and to investigate the effect of reaction conditions and crosslinker concentration on the properties of synthesized polymers. Detailed investigation into water‐uptake properties of these hydrogels was carried out as a function of time, temperature, and pH. The inherent properties of the monomer incorporated onto gelatin collectively act as determinant of the water‐absorption behavior of the hydrogels. Sorption of Fe+2, Cr+6, and Cu+2 ions from their aqueous solutions was also studied on select hydrogels, where it was observed that metal ions are sorbed by effective partitioning between hydrogels and solution phase and apart from the nature of metal ions, and structural aspects of hydrogels also determine the quantum of metal ion uptake. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 3856–3871, 2003
Synthesis of trimellitic anhydride microcapsule toner by liquid‐phase separation
Authors: Teshima Katsuya 
Published: October 2003

AbstractA microcapsule toner containing trimellitic anhydride for use as a foam inhibitor in printing applications was synthesized by liquid‐phase separation in organic solvents. It is possible to determine materials appropriate for the microencapsulation of trimellitic anhydride from solubility parameters calculated on the basis of the molecular structures of raw material candidates. Considering solubility parameters of various polymers, the polyethylene/methacrylic acid copolymer was selected for the microcapsule wall material. In addition, two kinds of solvents, toluene [solvent (a)] and isoparaffin [solvent (b)], were employed. It was necessary for the microcapsule materials to meet the following conditions: (1) the wall material must completely dissolve in solvent (a); (2) the core material must disperse well, but not dissolve in solvent (a); and (3) the wall and core materials must not dissolve in solvent (b). By using mixtures of either lecithin and basic barium petronate or lecithin and basic calcium petronate as charge control agents, the trimellitic anhydride microcapsules could be charged either positively and negatively, respectively. The microcapsule toner fabricated in this method was successfully applied in commercial printing machines, where it inhibited foaming effectively enough to satisfy product requirements in the printing industry. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 3822–3826, 2003
Elucidation of the miniemulsion stabilization mechanism and polymerization kinetics
Authors: Anderson Christopher D. , Sudol E. David , El‐Aasser Mohamed S. 
Published: October 2003

AbstractStyrene/hexadecane miniemulsions were polymerized at 50°C using a redox initiator. The miniemulsions and their corresponding latexes were characterized in terms of size, polymerization rate, and surface properties. The resulting data were analyzed to elucidate the miniemulsion stabilization and polymerization mechanisms. It was found that the free surfactant concentration exceeded the critical micelle concentration when large amounts of surfactant (60 mM sodium lauryl sulfate) were used, resulting in simultaneous micellar and droplet nucleation. Most surfactant was on the surface of the droplets (85%) or particles (95%). The fractional surface coverage was proportional to the surfactant concentration to the 0.55 power. Using a particle diameter equation, the number of particles was calculated to be proportional to the surfactant concentration to the 1.35 power. Through direct particle size measurements, a power of 1.38 was confirmed. The rate of polymerization was determined by reaction calorimetry to be proportional to the number of particles to the 0.59 power, in contrast to classical Smith–Ewart kinetics for conventional emulsions (1.0 power). The average number of radicals per particle was estimated from the rate and number data, and varied with the particle diameter to the 0.97 power. The observed kinetic dependencies were validated through an extension of Smith–Ewart theory. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 3987–3993, 2003
Natural abundance 15n solid‐state nmr study of nylon‐6 in blends
Authors: Tavares Maria Inês B. , De Souza Cláudia M. G. 
Published: October 2003

AbstractNatural abundance solid‐state nuclear magnetic resonance spectroscopy (NMR) of nitrogen‐15 (15N) was applied to investigate the films of nylon‐6 and their blends with poly(propylene oxide) (PPO). The NMR 15N results allowed us to identify the crystalline forms present in these blends and also confirmed the previous NMR results obtained by 13C‐NMR study. From all NMR data the antiplasticization phenomena and plasticization effects caused by PPO content, in the blends were characterized. The polyoxide action is a function of its proportion. However, because the samples were prepared by solution casting, the residual solvent action cannot be ignored. The 15N chemical shift changes were influenced by both PPO and residual solvent. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 3872–3875, 2003
Iodine doping of poly(3‐undecylbithiophene) and its composites with polystyrene using supercritical carbon dioxide
Authors: Abbett Kimberly F. , Teja Amyn S. , Kowalik Janusz , Tolbert Laren 
Published: October 2003

AbstractPartially doped conductive poly(3‐undecylbithiophene) and its composites with porous, crosslinked polystyrene were chemically doped with iodine using supercritical carbon dioxide to transport iodine to the conductive regions of the composite. The amount of iodine incorporated into the composite increased from 9.3 wt % at ambient conditions without carbon dioxide to 21.4 wt % in the presence of supercritical carbon dioxide. The conductivity of the composite increased by up to two orders of magnitude with iodine doping using supercritical carbon dioxide. The highest conductivity was obtained in samples treated at moderate temperatures and pressures (313 K and 20.7 MPa). © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 3876–3881, 2003
Thermoreversible gelation of nitrocellulose solutions
Authors: Mao Ching‐Feng , Chen Cheng‐Ho 
Published: October 2003

AbstractThermoreversible gelation of concentrated solutions of nitrocellulose was examined. The sol–gel transition diagrams were established using the ball‐drop method. The critical gel concentrations (Cgel), defined as the lowest concentration for gelation to occur, are approximately proportional to the reciprocal of the molecular weight of nitrocellulose. In addition, the values of Cgel[η] lie in the concentrated regime where entanglement effects are present. These facts suggest that the entanglement of polymer chains is a necessary condition for the formation of nitrocellulose gels. Moreover, the association of polymer segments is identified as another factor affecting the gel stability. This is evidenced by both the enhancement of the gel stability in poor solvents and the large enthalpy of mixing at low temperatures. Because of the presence of the association, the number of polymer chains in a junction point is larger than two, which is the value predicted by assuming entanglements as the only factor responsible for gelation. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 4000–4008, 2003
New route to the preparation of carboxymethylchitosan hydrogels
Authors: Janvikul Wanida , Thavornyutikarn Boonlom 
Published: October 2003

AbstractA new method to prepare CM–chitosan hydrogels was introduced with the use of steam. The procedure was simple and economical, with no toxic chemicals involved. The steam‐induced crosslinking of CM–chitosan sodium salt involved the –NH2 and –COONa groups, forming amide linkages (–CONH–), evidently supported by FTIR spectroscopy and other techniques. The hydrogels instantly imbibed a great deal of water. The degree of swelling (DS) of the hydrogels was found to be up to 36, depending on the harshness of steaming conditions used. Likewise, the coloration of the samples increased from light beige to brown with increasing temperature and duration of steam exposure. The overall efficiency of the steam method for the crosslinking of CM–chitosan sodium salt was quite high. The percentage weight loss was found to be less than 10 to obtain hydrogels with DS values around 20. No weight loss in the dry weight of the fractionated hydrogels was observed when the samples were steamed at 115°C or higher for 15 min or longer. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 4016–4020, 2003
Preparation of epoxy resin/silica hybrid composites for epoxy molding compounds
Authors: Liu Ying‐Ling , Lin Yu‐Lo , Chen Chih‐Ping , Jeng Ru‐Jong 
Published: October 2003

AbstractPhenolic novolac/silica and cresol novolac epoxy/silica hybrids were prepared through in situ sol‐gel reaction of tetraethoxysilane (TEOS). The formed hybrids were utilized as a curing agent and an epoxy resin in epoxy curing compositions, respectively. Via the two‐step preparation route, the resulting epoxy resin/silica hybrid nanocomposites exhibited good thermal stability, high glass transition temperatures, and low coefficients of thermal expansion. High condensation degree of the condensed silica was observed with a high content of siloxane bridges, p > 85%, measured by 29Si NMR. The two‐step route also provides feasibility of preparation of epoxy resin/silica hybrid nanocomposites compatible with the current processes of manufacturing of epoxy molding compounds. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 4047–4053, 2003
Thermal characterizations of semi‐interpenetrating polymer networks composed of poly(ethylene oxide) and poly(N‐isopropylacrylamide)
Authors: Kim Seon Jeong , Lee Chang Kee , Lee Young Moo , Lee Kyu Back , Park Yong Doo , Kim Sun I. 
Published: October 2003

AbstractPoly(N‐isopropylacrylamide) (PNIPAAm)/poly(ethylene oxide) (PEO) semi‐interpenetrating polymer networks (semi‐IPNs) synthesized by radical polymerization of N‐isopropylacrylamide (NIPAAm) in the presence of PEO. The thermal characterizations of the semi‐IPNs were investigated by differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and dielectric analysis (DEA). The melting temperature (Tm) of semi‐IPNs appeared at around 60°C using DSC. DEA was employed to ascertain the glass transition temperature (Tg) and determine the activation energy (Ea) of semi‐IPNs. From the results of DEA, semi‐IPNs exhibited one Tg indicating the presence of phase separation in the semi‐IPN, and Tgs of semi‐IPNs were observed with increasing PNIPAAm content. The thermal decomposition of semi‐IPNa was investigated using TGA and appeared at around 370°C. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 3922–3927, 2003