bluuebunny/crossref_metadata_2025_split huggingface dataset:
Seizure exacerbation associated with inhibition of progesterone metabolism
Authors: Herzog Andrew G. , Frye Cheryl A. 
Published: February 2003

AbstractThe reduced progesterone metabolite tetrahydroprogesterone is a potent positive modulator of GABAA chloride conductance that exerts powerful neuroinhibitiory and antiseizure effects in animal models. Cyclic natural progesterone use may lessen seizure frequency in women with catamenial seizure exacerbation. We report a case in which efficacy was eliminated during concomitant treatment with a reductase inhibitor. The observation suggests that a reduced metabolite, rather than progesterone itself, was responsible for improved seizure control. Ann Neurol 2003;53:390–391
Hippocampal sclerosis is a progressive disorder: A longitudinal volumetric MRI study
Authors: Fuerst Darren , Shah Jagdish , Shah Aashit , Watson Craig 
Published: February 2003

AbstractTwelve patients with refractory temporal lobe epilepsy and unilateral hippocampal sclerosis had repeat volumetric magnetic resonance imaging scans after a mean of 3.4 years to determine whether progressive hippocampal volume loss occurred. Seizure‐free patients showed no change in hippocampal volume. Patients with continuing seizures had a decline in ipsilateral hippocampal volume that correlated with seizure frequency. Patients with medically refractory temporal lobe epilepsy and unilateral hippocampal sclerosis have progressive hippocampal atrophy. Ann Neurol 2003;53:413–416
Outcome in psychogenic nonepileptic seizures: 1 to 10‐year follow‐up in 164 patients
Authors: Reuber Markus , Pukrop Ralf , Bauer Jürgen , Helmstaedter Christoph , Tessendorf Natalie , Elger Christian Erich 
Published: February 2003

AbstractOur knowledge of longer term outcome in psychogenic nonepileptic seizures (PNESs) patients is limited; we know less still about factors predicting prognosis. This study was intended to describe outcome in a large cohort and to identify predictive clinical and psychological factors to generate new ideas for treatment. One hundred sixty‐four adult patients with PNESs (66.7%) responded to outcome, personality, and psychosymptomatology questionnaires (Dimensional Assessment of Personality Pathology–Basic Questionnaire [DAPP‐BQ], Dissociative Experiences Scale, and Screening Test for Somatoform Symptoms) a mean of 11.9 years after manifestation and 4.1 years after diagnosis of PNES. Additional clinical data were retrieved from hospital records. The responses showed that 71.2% of patients continued to have seizures and 56.4% were dependent on social security. Dependence increased with follow‐up. Outcome was better in patients with greater educational attainments, younger onset and diagnosis, attacks with less dramatic features, fewer additional somatoform complaints, and lower dissociation scores. Better outcome was associated with lower scores of the higher order personality dimensions “inhibitedness,” “emotional dysregulation,” and “compulsivity” but not “dissocial behavior” (DAPP‐BQ). Outcome in PNESs is poor but variable. Clinical and personality factors can be used to provide an individualized prognosis. By generating a patient‐specific profile, they show particular maladaptive traits or tendencies that can identify goals for psychological therapy.
Free radical Co‐ and terpolymerization of styrene, hydrogenated cardanyl acrylate, and cardanyl acetate
Authors: Nguyen Le Huong , Koerner Hilmar , Lederer Klaus 
Published: February 2003

AbstractHydrogenated cardanyl acrylate (HCA) and cardanyl acetate (CACE) were synthesized from cardanol. The copolymerizations of HCA, CACE, and styrene (S) with methyl ethyl ketone peroxide (MEKP) and cobalt salt as the initiator were studied by FTIR. Based on FTIR results the reactivity ratios of the three copolymerization systems S–HCA, S–CACE, and HCA–CACE were determined by three different methods (Mayo‐Lewis, Fineman‐Ross, and Kelen‐Tüdos). Results obtained from the three methods are in good agreement. Instantaneous compositions and composition shift as a function of conversion is calculated for the S–HCA–CACE system with different feed compositions. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 1399–1409, 2003
Analysis of water trees in power cable polymeric insulation
Authors: Shuvalov M. , Mavrin M. , Ovsienko V. , Romashkin A. 
Published: February 2003

AbstractThis article deals with the basic mechanism of aging, that is water treeing (WT), that takes place in polymer‐insulated power cables. WT was studied by means of computer‐aided video‐enhanced microscopy, microspectrophotometry, and micromanipulation. The microdiagnostics procedure was used for cables operating in a wet environment. A phenomenological WT model aimed at estimating the residual lifetime, which considers WT as a diffusion‐with‐reaction process, was developed. The theoretical calculations were in reasonable agreement with the experimental data. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 1543–1549, 2003
Curing reaction of molybdenum–phenolic resins
Authors: Hua Youqing , Zhang Zhengxi , Qin Qian 
Published: February 2003

AbstractThe curing behavior and curing reaction kinetics of novel molybdenum–phenolic resins were studied with differential scanning calorimetry and thermogravimetry methods, the thermal degradation properties of the cured products were studied with thermogravimetry, and the mechanism of the curing reaction was investigated with Fourier transform infrared. When the mixing ratio of the molybdenum–phenolic resin (with 12% molybdenum) to the curing agent was 100/10 (w/w), the curing temperature and activation energy were at a minimum, the thermal degradation stability of the cured product was optimal, and the temperature corresponding to the maximum extent of curing was 200°C. The curing mechanism was similar to that of conventional phenolic systems. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 1410–1415, 2003
High polarization levels in poly(vinylidene fluoride–trifluoroethylene) ferroelectric thin films doped with diethyl phthalate
Authors: Xu Haisheng , Ni Suolong , Yang Changzheng 
Published: February 2003

AbstractWith a spin‐coating technique, ferroelectric thin films of poly(vinylidene fluoride–trifluoroethylene) copolymer [P(VDF–TrFE; with a content (mol %) ratio of 68/32 vinylidene fluoride/trifluoroethylene] were fabricated on silicon wafers covered with platinum and were doped with a nucleation agent, diethyl phthalate (DEP). The remnant polarization of copolymer thin films increased 70% after doping with DEP, and the coercive field was reduced, which is highly desirable in bistable memory devices. The dielectric constant of thin films also increased after doping. However, the effect of doping on the ferroelectric response was not remarkable in freestanding copolymer films. The results demonstrated that the ferroelectric dipole orientation in P(VDF–TrFE) thin films was significantly enhanced by the presence of DEP because the crystallinity of thin films decreased after doping, as revealed by X‐ray results. The dopant DEP acted as both a nucleation agent during the crystallization process and a plasticizer in the noncrystalline regions, which greatly enhanced the dipole orientation. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 1416–1419, 2003
Synthesis and properties of graft oxidation starch sizing agent
Authors: Zhang Xiaodong , Li Wenying Liuxin 
Published: February 2003

AbstractIn this article, a graft, oxidation starch sizing agent was synthesized and its structure and surface morphology were analyzed by infrared (IR) spectroscopy and scanning electron microscopy (SEM). The results show that the synthesized graft oxidation starch has good gelatinizing ability, good film properties, good desizing ability, and lower hygroscopic properties. The sized yarns (T/C65/35, 13.5tex), sized with graft oxidation starch and emulsive copolymer size EM, exhibit good tensile strength and elongation at break, good abrasion resistance, and lower counts of fluff when poly (vinyl alcohol) (PVA) is substituted by ≤ 80% with graft oxidation starch. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 1563–1566, 2003
Mechanical characterization of polypropylene–wood flour composites
Authors: Nuñez Adrián J. , Sturm Pablo C. , Kenny José M. , Aranguren M. I. , Marcovich Norma E. , Reboredo María M. 
Published: February 2003

AbstractThe mechanical performance of different wood flour/polypropylene (PP) composites with interface modifications was compared. Wood flour was incorporated into the matrix after esterification with maleic anhydride (MAN) or without any modification but with the addition of a compatibilizing agent [maleic anhydride–polypropylene copolymer (PPMAN)] to modify the polymer–filler interaction. Composites were prepared by injection molding with different concentrations of wood flour. Mechanical properties (except Young's modulus) were not improved either by the wood flour chemical modification or by the use of PPMAN. However, both compatibilization methods were successful in improving the dispersion of the wood flour in the PP matrix. Creep behavior of composite samples was improved by the addition of PPMAN, whereas the composites prepared from MAN‐treated wood flour showed larger deformations than composites made with untreated particles. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 1420–1428, 2003
Novel block ionomers. III. Mechanical and rheological properties
Authors: Fang Zheng , Wang Shanfeng , Wang Shi Quing , Kennedy Joseph P. 
Published: February 2003

AbstractSelect rheological (dynamic viscoelastic) and mechanical properties of novel block cationomers and anionomers and their blends have been investigated. The block ionomers were linear di‐ and triblocks, and symmetric three‐arm stars comprising hydrophobic polyisobutylene (PIB) blocks attached to ionized poly(methacrylic acid) (PMAA−X+, where X+ = Na+, Zn2+) and poly[2‐(dimethylamino)ethyl methacrylate] (PDMAEMA+I−) blocks. The specific structures investigated were the well‐defined diblocks PIB‐b‐PMAA− and PIB‐b‐PDMAEMA+ and their blends, the triblocks PMAA−‐b‐PIB‐b‐PMAA− and PDMAEMA+‐b‐PIB‐b‐PDMAEMA+ and their blends, and the three‐arm star anionomer Φ(PIB‐b‐PMAA−)3. For comparison, the properties of the precursor PIBs and unionized blocks have also been studied. Hydrogen bonding between the carboxyl groups of the PMAA blocks in PIB‐b‐PMAA diblocks leads to inverse micelles. Neutralization of the PMAA by Zn(AcO)2 and quaternization of the PDMAEMA segments by CH3I in the triblock copolymers and star copolymers yielded ionic domains, which self‐assemble and produce physical networks held together by coulumbic interaction. The physical/chemical characteristics of the domains control the viscoelastic behavior and mechanical properties of these block ionomers. The mechanical properties of the various block ionomers were significantly enhanced relative to the precursors, and they were thermally stable below the transition temperature. Further, the thermomechanical properties of these novel materials were satisfactory even above 200°C. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 1516–1525, 2003
Mechanical and rheological properties of the maleated polypropylene–layered silicate nanocomposites with different morphology
Authors: Koo Chong Min , Kim Mi Jung , Choi Min Ho , Kim Sang Ouk , Chung In Jae 
Published: February 2003

AbstractThree types of maleated polypropylene–layered silicate nanocomposites with different dispersion states of layered silicate (deintercalated, intercalated, and exfoliated states) are prepared from two kinds of polypropylenes with different molecular weights, organically modified layered silicate and pristine montmorillonite to investigate the effect of the final morphology of the nanocomposite on the rheological and mechanical properties. Maleated polypropylene with high molecular weight intercalates slowly and the other with low molecular weight exfoliates fast into the organophilic layered silicates. Rheological properties such as oscillatory storage modulus, nonterminal behavior, and relative viscosity has close relationship with the dispersion state of layered silicates. The exfoliated nanocomposite shows the largest increase and the deintercalated nanocomposite shows almost no change in relative shear and complex viscosities with the clay content. The exfoliated nanocomposite shows the largest drop in complex viscosity due to shear alignment of clay layers in the shear flow. In addition, the final dispersion state of layered silicates intimately relates to the mechanical property. The dynamic storage moduli of nanocomposites show the same behavior as the relative shear and complex viscosities. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 1526–1535, 2003
Characterization of graft polymerization of fluoroalkyl methacrylate onto PDMS hollow‐fiber membranes and their permselectivity for volatile organic compounds
Authors: Mishima S. , Nakagawa T. 
Published: February 2003

AbstractPolydimethylsiloxane (PDMS) hollow‐fiber membranes grafted with 1H,1H,9H‐hexadecafluorononyl methacrylate (HDFNMA), which is a fluoroalkyl methacrylate, using a 60Co irradiation source, were characterized and applied to pervaporation. The PDMS hollow‐fiber membranes were filled with N2 gas and sealed. The membranes and the HDFNMA solution were then irradiated simultaneously. In the HDFNMA solution, graft polymerization was performed. The degree of grafting of the outside surface of the hollow fiber was greater than that in the inside surface of the hollow fiber. In the grafted PDMS hollow‐fiber membranes, the best separation performance was shown due to the introduced hydrophobic polymer, poly(HDFNMA). The grafted membrane had a microphase‐separated structure, that is, a separated structure of PDMS and graft‐polymerized HDFNMA. The permeability of molecules in the poly(HDFNMA) phase was so low that the diffusion of molecules was prevented in the active layer with many poly(HDFNMA) domains, as the feed solution was introduced through the inside of the hollow fibers and the outside was vacuumed. As the feed solution was introduced through the outside of the hollow fibers and the inside was vacuumed, the diffusion of molecules was not prevented in the active layer with few poly(HDFNMA) domains. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 1573–1580, 2003
Continuous polymerization of lactam–lactone block copolymers in a twin‐screw extruder
Authors: Kim Byong Jun , White James L. 
Published: February 2003

AbstractContinuous copolymerizations of ϵ‐caprolactone with ϵ‐caprolactam and ω‐lauryl lactam were carried out in a modular intermeshing corotating twin‐screw extruder. Sodium hydride (initiator) and N‐acetyl caprolactam (coinitiator) were used to synthesize lactam–lactone copolymers in a twin‐screw extruder. We consider the variables of feeding order and feed rate of comonomers on the reactive extrusion of lactam–lactone copolymers. It was observed that simultaneous feeding of both monomers with initiator and coinitiator in the first hopper produced a mixture of homopolymers. When we fed the lactam into the first hopper and caprolactone sequentially into the second hopper, we obtained the lactam–caprolactone block copolymers. However, when we fed caprolactone first into the first hopper and the lactam into the second hopper, the extruded product was a mixture of poly(ϵ‐caprolactone) and lactam monomer. We synthesized high molecular weight copolymers of poly(caprolactam‐b‐caprolactone) and poly(lauryl lactam‐b‐caprolactone) with different block lengths by sequential feeding of monomers. The block length of the block copolymer could be adjusted by controlling the feed rate of each monomer during reactive extrusion. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 1429–1437, 2003
Model for the viscoelastic and viscoplastic responses of semicrystalline polymers
Authors: Drozdov Aleksey D. , deClaville Christiansen Jesper 
Published: February 2003

AbstractConstitutive equations are derived for the time‐dependent behavior of semicrystalline polymers at isothermal loading with small strains. A semicrystalline polymer at temperatures above the glass‐transition point for its amorphous phase is thought of as a network of macromolecules bridged by junctions (physical crosslinks, entanglements, and crystalline lamellae) that can slide with respect to their reference positions in the bulk material under straining. The network is assumed to be highly inhomogeneous, and it is modeled as an ensemble of mesoregions (MRs) with various strengths of interchain interaction. Two types of MRs are distinguished: passive, where these interactions prevent detachment of strands from junctions; and active, where active strands separate from junctions and dangling strands merge with the network at random times as they are thermally agitated. The viscoelastic response of a semicrystalline polymer reflects reformation of strands in active MRs, whereas its viscoplastic behavior is associated with sliding of junctions. Stress–strain relations for uniaxial deformation are developed by using the laws of thermodynamics. Adjustable parameters in the constitutive equations are found by fitting experimental data for isotactic polypropylene in a tensile test with a constant strain rate and in tensile relaxation tests at various strains. Fair agreement is demonstrated between the observations and the results of numerical simulation. It is revealed that the viscoplastic flow of junctions strongly affects the rearrangement process in active MRs, whose rate reaches a threshold value in the vicinity of the apparent yield point. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 1438–1450, 2003
Crosslinked poly(ethylene oxide) hydrogels
Authors: Emami Shahriar Hojjati , Salovey R. 
Published: February 2003

AbstractPoly(ethylene oxide) with a molecular weight of 2,000,000 was crosslinked by a difunctional peroxide in the molten state. We determined the molecular weight between crosslinks by swelling the samples with deionized water and by indentation and dynamic mechanical analysis. Results were compared with the calculated optimum molecular weight between crosslinks. Fair agreement was obtained between the experimental methods. However, the efficiency of peroxide‐induced crosslinking was very low. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 1451–1455, 2003
Immobilization of horseradish peroxidase on chitosan for use in nonaqueous media
Authors: Bindhu L. V. , Abraham Emilia T. 
Published: February 2003

AbstractChitosan, a natural polysaccharide, was used for the covalent immobilization of horseradish peroxidase, an enzyme of high synthetic utility, with the carbodiimide method. Of the enzyme, 62% was immobilized on chitosan when 1‐ethyl‐3‐(3‐dimethylaminopropyl carbodiimide) was used as the peptide coupling agent. The influence of different parameters, such as the enzyme concentration, carbodiimide concentration, and incubation period, on the activity retention of the immobilized enzyme was investigated. Kinetic studies using horseradish peroxidase immobilized on chitosan revealed the effects of several parameters, such as the substrate hydrophilicity and hydrophobicity, the solubility of substrates in the medium, the solvent hydrophobicity, and the support aquaphilicity, on the catalytic activity of the immobilized enzyme in nonaqueous media. General rules for the optimization of solvents for nonaqueous enzymology based on the partitioning of the solvent were not applicable for the immobilized horseradish peroxidase. The catalytic efficiency was greatest when o‐phenylene diamine was used as the substrate and least when guaiacol was used. The aquaphilicity of the support played an important role in the kinetics of the immobilized horseradish peroxidase in water‐miscible solvents. The results were promising for the future development of chitosan‐immobilized enzymes for use in organic media. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 1456–1464, 2003
Semiquantitative analysis of the thermal degradation of polypropylene
Authors: Ishikawa Tomoyuki , Ohkawa Tomohiro , Suzuki Masaaki , Tsuchiya Toshiaki , Takeda Kunihiko 
Published: February 2003

AbstractThe pyrolysis product distributions of polypropylene (PP) were observed, and the experimental data were semiquantitatively analyzed by computer simulation with the Molic mouse method. Studies by many researchers on PP decomposition and experimental results achieved in this study were examined. The product distributions were classified into three types of hydrocarbon products: 3n, 3n + 1, and 3n + 2 (n = monomer unit). The ratio showed the characteristic tendency, and the thermal degradation of PP appeared to include very complicated scission paths. The Molic mouse method, which was applied to the analysis of the thermal rearrangement and decomposition of poly(phenylene ether), was used to simulate the experimental results. After several steps by which the proper model was constructed, the scission probabilities to generate 2 × 3n, 3n + 1 and 3n + 2, 3n and 3n + 1, 3n and 3n + 2, C9, and C15 hydrocarbons were successfully calculated to be 0.25, 0.67, 0.47, 0.35, 1.0, and 0.33, respectively. This meant that the scission process of PP was very simple except for the C9 and C15 generation paths, for which the cyclic compounds were stable intermediates. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 1465–1472, 2003
Synthesis and crystallization behavior of nylon 12,14. I. Preparation and melting behavior
Authors: Li Yongjin , Zhang Guosheng , Yan Deyue 
Published: February 2003

AbstractA long‐alkane‐segment semicrystalline polyamide based on 1,12‐diaminododecane and 1,12‐dodecanedicarboxylic acid was synthesized and characterized. The polymer was prepared by melt polycondensation. The molecular weight of the material ranged from 20,000 to 40,000 g/mol, depending on the polymerization conditions. The resulting product was characterized by means of elemental analysis, infrared spectrometry, 1H‐ and 13C‐NMR, intrinsic viscosity, differential scanning calorimetry (DSC), thermogravimetric analysis, dynamic mechanical analysis, and wide‐angle X‐ray diffraction (WAXD). Some mechanical properties were measured. In addition, the thermal behavior of nylon 12,14 was systematically investigated with DSC and variable‐temperature WAXD. Double endotherms were observed during the melting of the polymer, which might have originated from the melt and recrystallization processes of nylon 12,14 on heating. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 1581–1589, 2003
Hydrophobic cotton fabric coated by a thin nanoparticulate plasma film
Authors: Zhang Jing , France Paul , Radomyselskiy Arseni , Datta Saswati , Zhao Jiangang , van Ooij William 
Published: February 2003

AbstractThe audio frequency (AC) plasma of some kind of fluorocarbon chemical was applied to deposit a nanoparticulate hydrophobic film onto a cotton fabric surface. The measurement of the video contact angle showed that the superhydrophobicity of the cotton fabric was obtained with a treatment of only 30 s. The softness, water retention, moisture regain, color retention, abrasion, friction, and permeability were thoroughly investigated by a standard method that compared the fabric with a commercial Scotchgard‐protector‐sprayed cotton fabric. The results showed that the textile performances of the plasma‐coated fabric were superior to those of Scotchgard‐sprayed samples, except for the moisture regain, which was almost the same. A post‐treatment at a high temperature was conducive to increasing the hydrophobicity and the recovery of the water repellency of the plasma‐coated fabric after it was washed. Atomic force microscopy images and time‐of‐flight secondary‐ion mass spectra of plasma thin films on silicon wafers indicated that some physical and chemical changes took place during the post‐treatment process. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 1473–1481, 2003