bluuebunny/crossref_metadata_2025_split huggingface dataset:
Early‐onset Parkinson's disease caused by a compound heterozygous DJ‐1 mutation
Authors: Hague Stephen , Rogaeva Ekaterina , Hernandez Dena , Gulick Cindy , Singleton Amanda , Hanson Melissa , Johnson Janel , Weiser Roberto , Gallardo Marisol , Ravina Bernard , Gwinn‐Hardy Katrina , Crawley Anthony , St. George‐Hyslop Peter H. , Lang Anthony E. , Heutink Peter , Bonifati Vincenzo , Hardy John , Singleton Andrew 
Published: July 2003

AbstractMutations in DJ‐1 have been linked to an autosomal recessive form of early‐onset parkinsonism. To identify mutations causing Parkinson's disease (PD), we sequenced exons 1 through 7 of DJ‐1 in 107 early‐onset (age at diagnosis up to 50 years) PD subjects. One subject had a frameshift mutation in the first coding exon and an exon 7 splice mutation both predicted to result in a loss of functional protein. This subject was diagnosed with probable PD at age 24 years with asymmetric onset and an excellent response to levodopa therapy. Our observations suggest that sequence alterations in DJ‐1 are a rare cause of early‐onset PD.
Mechanical, morphological, and thermal properties of rigid polyurethane foams blown by distilled water
Authors: Seo W. J. , Jung H. C. , Hyun J. C. , Kim W. N. , Lee Y.‐B. , Choe K. H. , Kim S.‐B. 
Published: July 2003

AbstractRigid polyurethane foams (PUFs) were prepared from polymeric 4,4′‐diphenylmethane diisocyanate (PMDI), polyether polyol, 1,4‐butanediol, silicone surfactant, and distilled water. The properties of the synthesized PUF samples were investigated with differential scanning calorimetry, scanning electron microscopy, and a Universal testing machine. The density of the PUF was decreased from 173.7 to 41.7 kg/m3 with an increase in distilled water from 0.5 to 3.0 parts per hundred polyol by weight (php), respectively, with 0 php butanediol. The cell size of the PUF sample increased from 115 to 258 μm with an increase in distilled water from 0.5 to 3.0 php, respectively, with 10 php butanediol. From the results of the thermal analysis of the PUF sample, it was found that the glass‐transition temperatures of the PUF samples were increased from 49.5 to 80.8°C with an increase in distilled water from 0.5 to 3.0 php, respectively, with 0 php butanediol. The results of the investigation of the mechanical properties of the PUF samples showed that the mechanical strength of the PUF samples was increased with the distilled water at equal density. The surfactant effect on the properties of the PUF was studied, and it was observed that the cell size of the PUF samples decreased from 360 to 146 μm with an increase in surfactant from 0 to 0.33 php, respectively. However, the cell size did not change significantly when the surfactant exceeded 0.33 php. The increase of the mechanical strength from 0 to 0.33 php surfactant was attributed to the decrease of the cell size of the PUF samples, and the decrease of the mechanical strength with more than 0.33 php surfactant might be due to the plasticized effect of the PUF samples. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 12–21, 2003
Structural transitions in commercial cellulose systems
Authors: Khanchich O. A. , Loshadkin D. V. , Rozantsev E. G. 
Published: July 2003

AbstractThe problems of phase transitions in commercial cellulose systems during processing are considered. The formation of structures in regenerated cellulose from viscose solutions during precipitation in different regenerated baths and in highly concentrated solutions of cellulose in N‐methylmorpholin‐N‐oxide at different temperatures and shear deformations has been selected for this review. The difficulties in defining the type of structural ordering in these systems are demonstrated. Fractal analysis is used to study the structures. A close relationship between the characteristics of the structures and the fractal dimensions is elucidated. The prospects for the different methods of regulating structures in cellulose systems are discussed. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 22–32, 2003
Miscibility studies of sodium alginate/poly(vinyl alcohol) blend in water by viscosity, ultrasonic, and refractive index methods
Authors: Ravi Prakash S. D. , Ramakrishna H. V. , Rai S. K. , Rajulu A. Varada 
Published: July 2003

AbstractThe miscibility of a sodium alginate/poly(vinyl alcohol) blend in water was studied by viscosity, ultrasonic velocity, and refractive index techniques at 30, 40, and 50°C. Using the viscosity data, interaction parameters μ and α were computed. These values revealed that the blend is miscible when the sodium alginate content is more than 50% in the blend. This was further confirmed by ultrasonic and refractive index methods. It was further observed that the temperature has only a marginal effect on the miscibility of this blend. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 33–39, 2003
Chemical and electrochemical synthesis of conducting graft copolymer of vinyl acetate with pyrrole and studies of its gas and vapor sensing
Authors: Hosseini S. Hossein , Entezami Ali A. 
Published: July 2003

AbstractCopolymers in general exhibit physical and mechanical properties far different from those of homopolymers and different from those of blends of the same individual homopolymers. Pyrrole (Py) 3 was grafted onto a poly(vinyl acetate) (PVAc) backbone that contained the Py moiety within via chemical and electrochemical oxidative polymerization. Graft copolymer 4 was soluble with low Py amounts but became rapidly insoluble with increasing Py content due to the formation of long Py sequences. The maximum conductivity of films cast from the reaction mixture was 8.3 × 10−3 S/cm. The product 4 was characterized and studied in detail using elemental analysis, ATR, 1H‐NMR, UV‐visibility, gel permeation chromatography (GPC), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and scanning electron microscopy (SEM). Gas sensors based on conducting polymers that exhibit electrical conducting properties can be used as specific toxic gas and vapor detectors. We report here effects of conductance and mass changes onto a graft copolymer 4 after exposure to hydrogen halides, hydrogen cyanide, 1‐3‐5 trichloromethyl benzene (TCMB), methylbenzyl bromide (MBB), bromobenzyl cyanide (BBC), cyanogen chloride (CC), and cyanogen bromide (CB), using two techniques: a four‐point probe method and a X‐ray fluorescence (XRF) device, respectively. Increasing of ratio polypyrrole (PPy) in the graft copolymer 4 increase the sensing properties of this copolymer and decrease the solubility of it. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 40–48, 2003
Conducting polymer blends of polypyrrole with polyvinyl acetate, polystyrene, and polyvinyl chloride based toxic gas sensors
Authors: Hosseini S. Hossein , Entezami Ali A. 
Published: July 2003

AbstractBlends of the conducting polymer, polypyrrole (PPy), and in the insulating host polymers, polyvinyl acetate (PVAc), polystyrene (PS), and polyvinyl chloride (PVC) resin, have been prepared chemically. Threshold conductivities occur at about 5% for PPy in blends with host polymers. The characterizations of these blends were done by FTIR, UV‐visible, differential scanning calorimetric (DSC), scanning electron microscopy (SEM), and thermal gravimetric analysis (TGA). The products of the blends have electrical conductivity comparable to PPy and mechanical properties similar to hosting polymers. The response mechanism of the conducting blends to a selection of gases and vapors was investigated using two techniques, measurement of conductance and mass changes using a four‐point probe method, and a X‐ray fluorescence (XRF) device, respectively. These responses of blends to toxic gases and vapors are more well explained. Prepared films were exposed to hydrogen halides (HCl, HBr, and HI), hydrogen cyanide, halogens (Cl2, Br2, and I2), monochloroacetic acid (MCAA), 1‐3‐5 trichloromethyl benzene (TCMB), methylbenzyl bromide (MBB), bromoacetone (BA), and cyanogen bromide (CB). The changes of conductivity of polymers frequently observed are partly due to one stage in the two‐stage sorption, perhaps involving the swelling of the polymer, then diffusion gases into polymer chains. The swelling of polymers is a slow process, therefore, preswelled polymer films tend to decrease the response times of blends with respect to gases. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 49–62, 2003
Adsorption of copper on specifically modified polyamide sorbent
Authors: Godjevargova T. , Mihova S. 
Published: July 2003

AbstractA novel, specific sorbent based on polyamide covalently immobilized with dead yeast cells by glutaraldehyde was prepared and characterized. This sorbent exhibits a high capacity for metal complexation based on multifunctional groups of dead cells, as well as a good stability for reuse based on the crosslinking agent, glutaraldehyde. The Cu2+ sorption characteristics of the polyamide modified with immobilized dead cells were studied and compared to those of the polyamide chemically modified without cells. The adsorption capacity of specifically modified polyamide was about 19‐fold higher than the chemically modified polymer. The adsorption isotherms of Langmuir and Freundlich for the new specific sorbent were determined. The effect of pH, temperature and co‐ions (Zn2+, Pb2+, Co2+, Ca2+ and Mg2+) on the Cu2+ sorption capacity were studied. The effectiveness of heavy metal desorption and the coefficient of recovery of sorption ability were determined. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 80–85, 2003
Sorption characterization of poly(vinyl alcohol)/chitosan interpenetrating polymer network hydrogels
Authors: Kim Seon Jeong , Lee Ki Jung , Kim Sun I. , Lee Kyu Back , Park Yong Doo 
Published: July 2003

AbstractPoly(vinyl alcohol) (PVA)/chitosan interpenetrating polymer networks (IPN) were prepared by UV irradiation. The water sorption behavior of the IPNs was measured at various temperatures and humidity levels. The water uptake of IPN13 is greater than that of other IPNs. Vapor sorption behavior is more affected by the density of water vapor than by hydrophilic properties with increasing temperature. Equilibrium water uptake increases as humidity increases, and the increase is more noticeable at high humidity. The sorption system of all IPNs is a relaxation‐controlled mechanism at a relative humidity (RH) of 90%, but it is a Fickian diffusion‐controlled mechanism when the RH is below 50%. With an increase in humidity, the diffusion coefficients were found to increase due to greater penetration of water into the IPNs. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 86–90, 2003
Electrical response characterization of chitosan/polyacrylonitrile hydrogel in NaCl solutions
Authors: Kim Seon Jeong , Shin Su Ryon , Lee Jang Han , Lee Sang Hoon , Kim Sun I. 
Published: July 2003

AbstractA semi‐interpenetrating polymer network (semi‐IPN) hydrogel composed of chitosan and polyacrylonitrile (PAN) exhibited electrical‐sensitive behavior. The swelling behavior of the semi‐IPN was studied by immersion of the gels in aqueous NaCl solutions at various concentrations. The swelling ratio decreased with an increase in the concentration of the electrolyte solution. The stimulus response of the semi‐IPN hydrogel in electric fields was also investigated. When swollen, the semi‐IPN was placed between a pair of electrodes, and it exhibited bending behavior upon application of an electric field. The electro responsive behavior of the semi‐IPN was also affected by the electrolyte concentration of the external solution. The semi‐IPN also showed various degrees of increase in bending behavior depending on the electrical stimulus. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 91–96, 2003
Interrelation between dyeing and thermal properties of PET fibers
Authors: De Clerck K. , Rahier H. , Van Mele B. , Kiekens P. 
Published: July 2003

AbstractThe interrelation between dyeing and the thermal properties of micro and conventional poly(ethylene terephthalate) fibers is studied with conventional and modulated differential scanning calorimetry. X‐ray diffraction, density, and birefringence studies are used to confirm the obtained results. It is shown that three studied anthraquinone dyes, in contrast to three studied benzodifuranone dyes, act as plasticizers for the fibers. A comparison between fibers and partially crystallized bulk samples is made. The specific fiber morphology makes the fibers more susceptible to plasticization than are bulk samples. This ability of a dye to lower the glass transition of the fibers will influence the dye diffusion and this information is needed to optimize the dyeing process for a specific dye–fiber combination. Further, the presence of an anthraquinone dye in the fiber alters the melting endotherm by changing the stability of the original crystals. The onset of the melting and recrystallization process is lowered. Although still well above the dyeing temperature, this lowering may be critical for the dimensional stability of the fabrics during any subsequent high‐temperature process. A first investigation of the effect of variations in the thermal properties on the obtained color strength after dyeing is reported. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 105–114, 2003
Effects of vacuum ultraviolet on the structure and optical properties of poly(tetrafluoroethylene) films
Authors: Peng Guirong , Yang Dezhuang , Liu Jincheng , He Shiyu 
Published: July 2003

AbstractThe effects of vacuum ultraviolet (VUV) at wavelengths of 5–200 nm on the microscopic structure and optical properties of poly(tetrafluoroethylene) (PTFE) films were investigated. X‐ray photoelectron spectroscopy analysis showed that the C1s spectra changed from a single peak at 292.8 eV to multiplex peaks with binding energies of 284.6, 286.6, 288.6, 290.5, and 293.0 eV after VUV irradiation at 680 esh. With an increasing irradiation dose, the C1s peaks at 290.5 and 293.0 eV disappeared. After the PTFE film specimens irradiated at 1600 esh were sputtered with argon ions for 3 min, the C1s peaks at 290.5 and 293.0 eV appeared again, and the height of the peaks at 286.6 and 288.6 eV increased. The content of fluorine decreased after VUV irradiation. The content of fluorine in the film surface layer decreased significantly with the increase in the VUV intensity, but it did not change with the irradiation dose. Fourier transform infrared (FTIR) analysis results indicated that some conjugated bonds, such as FCCF, were formed during VUV irradiation, but no CH absorption bands were observed in the FTIR spectra; this indicated that the increase in the height of the C1s peak at 284.6 eV arose mainly from the carbon–carbon bonds, that is, from carbonification. The spectral transmittance of the PTFE film decreased gradually with an increasing VUV irradiation dose, and at a given dose, the lower the intensity was of the VUV irradiation, the greater the change was in the spectral transmittance. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 115–121, 2003
Graft copolymerization of acrylonitrile onto Cassia tora gum with ceric ammonium nitrate–nitric acid as a redox initiator
Authors: Sharma Brij Raj , Kumar Vineet , Soni P. L. 
Published: July 2003

AbstractThe graft copolymerization of acrylonitrile (AN) onto Cassia tora gum (CTG) was carried out in an aqueous medium with a ceric ammonium nitrate (CAN)–nitric acid initiation system. The percentage grafting and percentage grafting efficiency were determined as functions of the concentrations of CAN, nitric acid, AN, and CTG and the polymerization temperature and time. The results are discussed, and a reaction mechanism is proposed. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 129–136, 2003
Computer simulation method for calculating concentration profiles in polyurethane/polystyrene interpenetrating polymer network membranes
Authors: Siddaramaiah  , Kumar H. , Roopa S. , Kendagannaswamy B. K. , Aminabhavi T. M. 
Published: July 2003

AbstractInterpenetrating polymer networks (IPNs) of polyurethane (PU) and polystyrene (PS; 90/10 and 75/25) were synthesized by the condensation reaction of castor oil with methylene diisocyanate and styrene, with benzoyl peroxide as an initiator. The IPN membranes were characterized for physicomechanical, optical, and X‐ray diffraction properties. Computer‐simulated concentration profiles of aqueous salt solutions through PU/PS IPN membranes were generated with Fick's second‐order differential equation, and the results were examined in terms of diffusion anomalies. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 122–128, 2003
Soluble and crosslinked hydrophilic films based on compositions of poly(acrylic acid) and poly(2‐hydroxyethyl vinyl ether) for controlled drug release
Authors: Nurkeeva Z. S. , Mun G. A. , Khutoryanskiy V. V. , Bitekenova A. B. , Dzhusupbekova A. B. , Park K. 
Published: July 2003

AbstractSoluble and crosslinked films based on compositions of poly(acrylic acid) and poly(2‐hydroxyethyl vinyl ether) were prepared. Solubility, morphology, mechanical characteristics, and swelling properties of the films were investigated. Potential applications of the polymer complex films in controlled drug delivery were also examined. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 137–142, 2003
Characterization and application of polypropylene films modified with stimuli‐sensitive copolymers with an Ar‐plasma postpolymerization technique
Authors: Sugiyama Kazuo , Shiraishi Kohei , Sono Kazuro 
Published: July 2003

AbstractSurface‐modified polypropylene (PP) films with thermally and photochemically sensitive copolymers consisting of N‐(2‐hydroxypropyl)methacrylamide (HPMA) and 4‐(4‐methoxyphenylazo)phenyl methacrylate (MPAP), poly(HPMA‐co‐MPAP)‐g‐PP (abbreviated g‐PP) film, were prepared by graft copolymerization with an Ar‐plasma postpolymerization technique. The surfaces of the g‐PP films were characterized by means of X‐ray photoelectron spectroscopy; the percentage grafting of poly(HPMA‐co‐MPAP) with a number‐average molecular weight of 3.28 × 104 was 7.12%, and the molar ratio of HPMA–MPAH in the copolymer was 0.75:0.25. The stimuli‐sensitive adsorption of albumin and polystyrene microspheres on the g‐PP film was also measured. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 143–148, 2003
Preparation of ion‐exchange membranes by hydrolysis of radiation‐grafted polyethylene‐g‐polyacrylamide membranes
Authors: Gupta Bhuvanesh , Anjum Nishat 
Published: July 2003

AbstractPolyethylene‐g‐polyacrylamide membranes were prepared by graft polymerization of acrylamide onto polyethylene films using a preirradiation method. The ion‐exchange membranes were obtained by the hydrolysis of grafted films so as to transform amide groups into carboxyl groups. The fraction of amide groups transformed into carboxyl groups was limited to ∼0.5. The characterization and thermal behavior of membranes with different degrees of grafting were evaluated by FTIR, thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC) measurements. The heat of fusion and the crystallinity of polyethylene decreased considerably in the hydrolyzed membranes depending on the degree of grafting. It was found that the grafting of acrylamide led to the reduction in crystallinity due to disruption of the crystallites (crystal defects) and dilution of the inherent crystallinity (dilution effect). The contribution of the hydrolysis step to the crystallinity decrease was negligible. The thermal stability of the membranes as obtained from TGA showed considerable enhancement after hydrolysis. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 149–154, 2003
Introduction of molecular spacers between the crosslinks of a cellulose‐based superabsorbent hydrogel: Effects on the equilibrium sorption properties
Authors: Sannino A. , Maffezzoli A. , Nicolais L. 
Published: July 2003

AbstractThe possibility to modulate cellulose‐based hydrogel sorption properties through the insertion of molecular spacers between the crosslinks was investigated. Starting polymers were the sodium salt of carboxymethyl cellulose, a polyelectrolyte cellulose derivative, and hydroxyethyl cellulose, a nonpolyelectrolyte derivative. Poly(ethylene glycol) with various molecular weights was linked by its free ends at two divinyl sulfone (DVS) crosslinker molecules, to increase the average distance between two crosslinking sites and thus to act as a spacer. Both the effect of the concentration and the molecular weight of the spacer on the hydrogel final sorption properties in water and water solutions were investigated. The presence of the spacer allowed us also to perform hydrogel synthesis with higher concentrations of cellulose in the reactive mixture, and the effect of the polymer concentration in the batch was analyzed. Hydrogels obtained in the presence of spacers displayed significantly higher equilibrium sorption properties than those of the ones obtained without spacers. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 168–174, 2003
Morphology and mechanical properties of polypropylene and poly(ethylene‐co‐methyl acrylate) blends
Authors: Genovese A. , Shanks R. A. 
Published: July 2003

AbstractThe morphology and mechanical properties of isotactic polypropylene (iPP) and poly(ethylene‐co‐methyl acrylate) (EMA) blends were investigated. Various EMA copolymers with different methyl acrylate (MA) comonomer content were used. iPP and EMA formed immiscible blends over the composition range studied. The crystallization and melting reflected that of the individual components and the crystallinity was not greatly affected. The size of the iPP crystals was larger in the blends than those of pure iPP, indicating that EMA may have reduced the nucleation density of the iPP; however, the growth rate of the iPP crystals was found to remain constant. The tensile elongation at break was greatly increased by the presence of EMA, although the modulus remained approximately constant until the EMA composition was greater than 20%. EMA with a 9.0% MA content provided the optimum effect on the mechanical properties of the blends. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 175–185, 2003
Effect of high‐temperature annealing on the elastoplastic response of isotactic polypropylene in loading–unloading tests
Authors: Drozdov A. D. , de C. Christiansen J. 
Published: July 2003

AbstractA series of uniaxial tensile loading–unloading tests is performed on isotactic polypropylene at room temperature. Prior to mechanical testing, injection‐molded specimens are annealed for 24 h at temperatures T = 145, 150, 155, 158, 160, 163, and 165°C, which cover the entire region of high‐temperature annealing temperatures. A constitutive model is developed for the elastoplastic behavior of a semicrystalline polymer at small strains. The stress–strain relations are determined by six adjustable parameters that are found by matching observations in cyclic tests. Fair agreement is demonstrated between the experimental data and the results of numerical simulation. It is shown that all material constants are affected by the annealing temperature, which is explained by changes in the crystalline morphology driven by thermal treatment. Some of the adjustable parameters experience finite jumps in the vicinity of the critical temperature Tc = 159°C. These jumps are attributed to the α2 → α2′ phase transformation. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 186–196, 2003