bluuebunny/crossref_metadata_2025_split huggingface dataset:
Evidence for strength imbalances as a significant contributor to abnormal synergies in hemiparetic subjects
Authors: Lum Peter S. , Burgar Charles G. , Shor Peggy C. 
Published: January 2003

AbstractAbnormal synergies in the paretic shoulder and elbow of hemiparetic subjects were quantified during maximal voluntary contractions (MVCs) in 27 subjects with a history of stroke and 8 age‐matched control subjects. A six‐axis load cell allowed simultaneous measurement of the primary torque the subject was attempting to maximize and the secondary torques at other joint actions. For example, during MVC of shoulder flexion, shoulder flexion is the primary torque and the secondary torques are internal/external rotation, abduction/adduction, and elbow flexion/extension. In general, the stroke subjects had increased secondary torques compared to controls, resulting in abnormal joint torque coupling within the set consisting of elbow flexion, internal rotation, adduction, shoulder flexion. Unlike previous studies, abnormal secondary torques in several cases were due to strength imbalances, which occur when the strength deficit for a particular joint action is greater than the strength deficit in the opposite joint action. This hypothesis was supported by electromyographic recordings and by the finding that subjects with larger strength imbalances tended to produce larger secondary torques. Possible mechanisms and consequences for rehabilitative treatments are discussed. Muscle Nerve 27: 211–221, 2003
Endurance training alters the biophysical properties of hindlimb motoneurons in rats
Authors: Beaumont Eric , Gardiner Phillip F. 
Published: January 2003

AbstractThe purpose of the study was to determine the effect of daily endurance treadmill training (2 h/day, 30 m/min) on motoneuron biophysical properties. Electrophysiological properties of tibial motoneurons were measured in situ in anesthetized (ketamine/xylazine) control and trained rats using sharp glass microelectrodes. Motoneurons from trained rats had significantly hyperpolarized resting membrane potentials and spike trigger levels, and faster antidromic spike rise‐times. “Fast” motoneurons (after‐hyperpolarization half‐decay time <20 ms) in trained rats also had a significantly larger mean cell capacitance than those in control rats, suggesting that they were larger, although this had no effect on indices of excitability (rheobase, cell input resistance). Motoneurons are thus targets for activity‐induced adaptations, which may have clinical significance for the role of physical activity as a therapeutic modality in cases of neurological deficit. The specific adaptations noted, which reflect alterations in ionic conductances, may serve to offset decreases in membrane excitability that occur during sustained excitation. © 2003 Wiley Periodicals, Inc. Muscle Nerve 27: 228–236, 2003
Size of motor unit potential sample
Authors: Podnar Simon , Mrkaić Mićo 
Published: January 2003

AbstractIn quantitative electromyography (EMG), a sample size of 20 motor unit potentials (MUPs) is standard. The effect of increase in the number of MUPs above 20 is not known, although advanced MUP analysis techniques make such samples practical. In the present study, using multi‐MUP analysis, pools of 3,720 neuropathic and 2,526 control MUPs were obtained from external anal sphincter muscles. From each pool, 10,000 random samples of 5, 10, 15, 20, 30, 40, 50, and 100 MUPs were obtained by a computer. For each sample size, 95% normative limits for mean values, SDs, and “outliers,” and sensitivities were calculated for eight MUP parameters. As the magnitude of MUP samples increased, normative limits narrowed and sensitivities increased (at 5: 20–30%; at 20: 30–55%; at 100: 80–100%) for all statistics of all MUP parameters. Our results demonstrated a substantial increase in sensitivity by increasing the MUP sample to more than 20. This option deserves consideration in an attempt to improve the usefulness of quantitative EMG. Muscle Nerve 27: 196–201, 2003
Early prednisone treatment in Duchenne muscular dystrophy
Authors: Merlini Luciano , Cicognani Alessandro , Malaspina Elisabetta , Gennari Monia , Gnudi Saverio , Talim Beril , Franzoni Emilio 
Published: January 2003

AbstractThe purpose of this long‐term, open parallel‐group, double‐consent study of alternate‐day, low‐dose prednisone in 2–4‐year‐old patients with Duchenne muscular dystrophy (DMD) was to determine whether prednisone produces a beneficial effect when given earlier than usual. Muscle function was evaluated by timed tests, and muscle strength with a hand‐held myometer. After 55 months of treatment, the five patients (mean age 8.3 years) in the prednisone group were still able to get up from the floor, whereas two of the three in the control group had lost this ability. Side effects included a decline in growth rate in the prednisone‐treated patients and excessive weight gain in one control and three treated patients. Because steroids are effective in prolonging function, but not in recovering lost function, we propose that treatment be started with low‐dose prednisone in DMD patients as soon as the diagnosis is definite. Muscle Nerve 27: 222–227, 2003
Individual attributes versus composite scores of nerve conduction abnormality: Sensitivity, reproducibility, and concordance with impairment
Authors: Dyck Peter J. , Litchy William J. , Daube Jasper R. , Harper C. Michel , Dyck P. James B. , Davies Jenny , O'Brien Peter C. 
Published: January 2003

AbstractComposite scores may be more sensitive and reproducible than single attributes of nerve conduction for detection of peripheral neuropathy, but this requires validation in large patient cohorts. Also, the concordance of individual attributes versus composite scores with clinical measures of severity has not been tested. Here, we study these issues in prospectively studied cohorts: diabetic patients from Rochester, Minnesota (RDNS; n = 396); chronic inflammatory demyelinating polyneuropathy (CIDP) patients (n = 55); and multifocal motor neuropathy (MMN) patients (n = 18). With specificity fixed at the 97.5 percentile, we found that, in generalized polyneuropathies (diabetic and CIDP), composite scores (especially ones including conduction velocity, distal latencies, and F‐waves) of individual or multiple nerves tended to be more sensitive than individual attributes. By contrast, for multiple mononeuropathies, some individual attributes or composite scores of individual nerves were more sensitive than composite scores. In diabetic polyneuropathy, composite scores tended to be more reproducible than individual attributes of nerve conduction. Highly significant correlations were found between individual attributes or composite scores and neurologic impairment in diabetic polyneuropathy and in CIDP; in general, correlation coefficients were higher for composite scores. These correlations were higher for amplitudes than for conduction velocities or distal latencies. We conclude that, with the availability of microprocessors and normative databases, electromyographers may increasingly seek to express nerve conduction abnormality also as composite scores of individual or several nerves. Muscle Nerve 27: 202–210, 2003
Factors affecting the adsorption of ethoxylated nonyl phenol onto synthetic rubber
Authors: El‐Feky A. A. , Shalaby M. N. 
Published: January 2003

AbstractAdsorption of non‐ionic surfactant (ethoxylated nonyl phenol; ENP) from aqueous solution is studied at 30 °C using butyl rubber (II R) mixed with two types of carbon black: high abrasion furnace (HAF) and general purpose furnace (GPF) as fillers with different concentrations. The results indicate that butyl loaded with HAF is more efficient as adsorbent surface than that loaded with GPF irrespective of the carbon black concentration and the adsorption increases as the immersion time increases. The experimental data of adsorption isotherms could be fitted to the Langmuir equation below the critical micelle concentration (CMC) of ENP. Copyright © 2003 John Wiley & Sons, Ltd.
Morphology and properties of ternary polyamide 6/polyamide 66/elastomer blends
Authors: Tomova D. , Radusch H.‐J. 
Published: January 2003

AbstractThe aim of the work presented is to evaluate the mechanisms and phase interactions in ternary blends based on different polyamides and functionalised elastomers, and to establish a correlation between the morphology controlled by the specific binary interactions, and physical and technological properties, respectively.The properties of the ternary system polyamide 6/polyamide 66/ elastomer depend on the specific blend morphology which is determined mainly by the differences of the surface tension of the components. A phase‐in‐phase structure was observed by microscopic study (AFM) in the ternary polyamide 6/polyamide 66/elastomer blends with maleic anhydride grafted ethene‐octene copolymer, and a “quasi” phase‐in‐phase structure in blends with maleic anhydride grafted ethene‐propene‐diene copolymer as the elastomer phase. An incorporation of polyamide inside of the elastomer particles was observed in the first case due to the difunctionality of polyamide 66. This type of morphology causes an increased elongation at break and toughness of these blends.In comparison to the binary polyamide based blends the ternary blends show an increased elastic modulus, elongation at break and yield stress as well as a high impact strength at low temperatures up to −20 °C. Copyright © 2003 John Wiley & Sons, Ltd.
Catalysis of intumescent flame retardancy of polypropylene by metallic compounds
Authors: Lewin Menachem , Endo Makoto 
Published: January 2003

AbstractDivalent and multivalent metallic compounds catalyze the flame retardancy performance of intumescent systems based on ammonium polyphosphate (APP) and pentaerythritol (petol) in poly(propylene) (PP). The catalytic effect is shown by increases in the oxygen index (OI) and UL‐94 ratings. The effect is exerted by small concentrations of the metallic compounds in the range of 0.1–2.5 wt% of the compositions. The effect increases with the concentration of the catalyst until a maximum is reached. At higher concentrations of the catalyst a decrease in the flame retardancy parameters is observed, accompanied in several cases by a degradation and discoloration of the composition. The catalyst replaces melamine in intumescent systems. Catalytic effectiveness is defined and calculated for a number of compounds. Thermogravimetric parameters, such as initial decomposition temperature, temperature of the transition point and residue‐after‐transitions (RAT) change in parallel with the catalytic effect of the metal compound concentration. Metal compounds investigated include oxides, acetates, acetyl acetonates, borates and sulfates of Mn, Zn, Mg, Al, Ca, Ba, V, Co, Ni, Cu, Mo, Zr, and Cr. Mechanistic considerations on the activity of the catalysts are presented. Copyright © 2003 John Wiley & Sons, Ltd.
Synthesis of new chitosan derivatives and combination with biodegradable polymer
Authors: Omura Yoshihiko , Renbutsu Eiko , Morimoto Minoru , Saimoto Hiroyuki , Shigemasa Yoshihiro 
Published: January 2003

AbstractNew chitosan derivatives are synthesized by the reductive N‐alkylation reaction of chitosan with various aldehydes, such as 2,4‐dihydroxybenzaldehyde, cholesteryl 4‐formylbenzoate, and N‐dehydroabietyl‐4‐formylbenzamide. The palladium‐adsorption ability of the newly synthesized derivatives is found to be as good as that of chitosan. A blend of chitosan and other biodegradable polymers is also found to exhibit palladium‐adsorption ability. In comparison to the starting chitosan, the chitosan derivative having dehydroabietyl‐type side chains exhibited an improved solubility in methanol. The chitosan derivatives are successfully applied as plastic coating materials for electroless plating. Copyright © 2003 John Wiley & Sons, Ltd.
Regioselective synthesis and biological activity of oxidized chitosan derivatives
Authors: Terada Naofumi , Morimoto Minoru , Saimoto Hiroyuki , Okamoto Yoshiharu , Minami Saburo , Shigemasa Yoshihiro 
Published: January 2003

AbstractOxidized chitosan derivatives with various degrees of oxidation (DS, 0.1–1.0) were prepared by the treatment of chitosan with CrO3/aq HClO4 or by the oxidation of ­3‐O‐ and N‐protected chitosan with 30% aq H2O2/Na2WO4 followed by 3‐O‐ and N‐deprotection. The oxidized products were then N‐acetylated with Ac2O in order to improve their water‐solubility. Although the oxidized chitosan derivative of DS 0.28 and the degree of N‐acetylation of chitosan (DA) 38% was insoluble in the pH 3–8 region, that of DS 0.26 and DA 76% was soluble in the neutral pH range. The newly‐prepared acetylated and oxidized chitosan derivatives were found to suppress the chemiluminescence response of inflammatory cells such as canine polymorphonuclear cells (PMNs). Analysis by the surface plasmon resonance method revealed that the bind and release behavior of PMNs to acetylated oxidized chitosan derivatives was similar to that against carboxymethylated chitosan derivatives. The amount of water‐soluble chitosan derivative bound to cytokine IL‐8 was found to be affected by the structural and electronic features of the chitosan substituents in the chitosan chain. Copyright © 2003 John Wiley & Sons, Ltd.
A novel oligothiophene derivative as a hole‐transport with emitting material for OLED
Authors: Cho Jun‐Sang , Kojima Yojiro , Yamamoto Kimihisa 
Published: January 2003

AbstractA novel oligothiophene derivative containing the triphenylamine moiety with high glass transition temperature (Tg; 135 °C), 5,5′‐{bis[4‐di(4‐thiophenyl)amino]phenyl}‐2,2′‐bithiophene (TTPA‐dimer) was synthesized by the dimerization of tris[4‐(2‐thienyl)phenyl]amine (TTPA) with a palladium catalysis. Some types of electroluminescent (EL) devices that use the amorphous material for a hole‐ and an electron‐transporting with an emitting layer were fabricated. These devices emitted a bright green‐yellowish light (λemi; around 510 nm) with a small full width at half maximum (FWHM) rather than that of Alq3. The single layer EL device showed a maximum luminance of 221 cd/m2 at 8 V (0.06 lm/W at 100 cd/m2). On the other hand, the double layer (TTPA‐dimer/Alq3) EL device that used Alq3 as the electron transport material was increased up to 10830 cd/m2 at 12 V (0.89 lm/W at 300 cd/m2) and with a lower turn‐on voltage (3.2 V at 0.1 cd/m2) than other types of EL devices. Copyright © 2003 John Wiley & Sons, Ltd.
Synthesis and characterization of polyethylene‐g‐polystyrene as the compatibilizer for polypropylene/ Polystyrene blends
Authors: Kim J. , Kwak J. , Kim D. 
Published: January 2003

AbstractPolyethylene‐g‐polystyrene (PE‐g‐PS) was synthesized as a compatibilizer for polypropylene/polystyrene­(PP/PS) blends by the living radical polymerization of styrene with polyethylene‐co‐glycidylmethacrylate (PE‐co‐GMA). The compatibilizer effect of PE‐g‐PS on the morphology and thermal properties of PP/PS blends was investigated. The crystalline temperature of PP in PP/PS blends decreased with increasing PE‐g‐PS contents. Morphologies of PP/PE‐g‐PS/PS blends showed much better dispersion of each domain for higher PE‐g‐PS contents. The molecular weight of PS segment in PP/PE‐g‐PS/PS blend was increased by addition of styrene monomer during the post melt blending process where post living radical polymerization reaction proceeded. Copyright © 2003 John Wiley & Sons, Ltd.
Organic/Inorganic NLO materials based on reactive polyimides and a bulky alkoxysilane dye via sol/Gel process
Authors: Jeng Ru‐Jong , Hung Wei‐Yu , Chen Chih‐Ping , Hsiue Ging‐Ho 
Published: January 2003

AbstractA series of the organic–inorganic materials based on reactive polyimides and a bulky alkoxysilane dye (ASD) for second‐order nonlinear optics have been developed. Sol‐gel reaction of ASDs is utilized to grow a network in polymer matrices (composite) or to create inter‐polymer network among polyimide chains (hybrid). Moreover, a full interpenetrating polymer network (IPN) was formed through simultaneous free radical polymerization of a methacryloyl group containing polyimide, and sol‐gel process of ASDs. Scanning electron microscopy (SEM) results indicate that the inorganic networks are distributed uniformly throughout the polymer matrices on the molecular scale. The silica particle sizes are well under 1 µm based on AFM study. Second harmonic coefficients, d33 of 4.5 to 48.5 pm/V have been obtained for the optically clear poled/cured polyimide/ASD samples. Excellent temporal stability was obtained for these NLO materials at 100 °C. The dynamic thermal and temporal stabilities of the IPN system were much better than those of composite and hybrid systems. Copyright ­© 2003 John Wiley & Sons, Ltd.
Preparation and evaluation of a nanocomposite of polythiophene with Al2O3
Authors: Ballav Nirmalya , Biswas Mukul 
Published: January 2003

AbstractThe polymerization of thiophene (TP), in bulk and in solution in CHCl3 by FeCl3 resulted in the formation of a polymer which was characterized by FTIR as polythiophene (PTP). High yield was realized in the latter case. The polymerization of TP with FeCl3 and nanodimensional Al2O3 resulted in the formation of a nanocomposite which was partly dispersible in aqueous and non‐aqueous media. The dispersibility appeared to be higher when the polymerization was conducted in a suspension containing a higher amount of Al2O3. Scanning electron micrographs showed globular particles and the presence of clusters of composite particles. Transmission electron micrographic (TEM) analyses revealed the particle size of the composite to be in the range 22–74 nm. Thermal analyses (TG/DTA) revealed the outstanding stability of PTP–Al2O3 composites compared to that of PTP. The conductivity of PTP and of PTP–Al2O3 composite was of the order of 10−3 S cm−1 for samples doped with I2.© 2003 Society of Chemical Industry
Ultrasonic improvement of rheological and processing behaviour of LLDPE during extrusion
Authors: Guo Shaoyun , Li Yuntao , Chen Guangshun , Li Huilin 
Published: January 2003

AbstractThe effects of ultrasonic oscillations on die pressure, productivity of extrusion, melt viscosity and melt fracture of linear low density polyethylene (LLDPE) as well as their mechanism of action were studied in a special ultrasonic oscillation extrusion system developed in our Laboratory. The experimental results showed that, in the presence of ultrasonic oscillations, the melt fracture or surface distortion of LLDPE extrudate is inhibited or disappears. The surface appearance of the LLDPE extrudate was greatly improved. The productivity of LLDPE extrudate was increased in the presence of ultrasonic oscillations. The die pressure, melt viscosity and flow activation energy of LLDPE decreased with the rise in ultrasonic intensity. The shear sensitivity of LLDPE melt viscosity decreased due to the increase of its power law index in the presence of ultrasonic oscillations. Inducing ultrasonic oscillations into LLDPE melt greatly improved its processability. A possible mechanism for the improved processibility is proposed.© 2003 Society of Chemical Industry
Fireproofing of polyurethane elastomers by reactive organophosphonates
Authors: El Khatib Wassef , Youssef Boulos , Bunel Claude , Mortaigne Bruno 
Published: January 2003

AbstractPolyurethane elastomers were prepared with hydroxytelechelic polybutadiene (HTPB) as polyol, modified 4,4′‐diphenylmethane diisocyanate (modified MDI) as liquid polyisocyanate, and phosphonate diols as chain extenders and flame retardant compounds. These phosphonate diols were synthesized by radical thiol–ene addition of allyl or vinyl dialkyl phosphonate to 3‐mercapto‐1,2‐propanediol. For various percentages of phosphorus (0 to 3%, w/w), polyurethane elastomers remain stable up to 250 °C. The percentage of residual char at 600 °C increases with increasing phosphorus content. For the soft segments, no variation in the glass transition temperature (Tg) is observed as the percentage of P increases, whereas the Tg of hard segments increases. Above 0.5% phosphorus content, the limiting oxygen index (LOI) becomes higher than the percentage of oxygen in the air.© 2003 Society of Chemical Industry
Thermal analysis, glass transition temperature and rheological behaviour of emulsion copolymers of methyl methacrylate with styrene
Authors: Zhang Liucheng , Liu Guodong , Ji Rongqin , Yao Yanmei , Qu Xiongwei , Yang Liting , Gao Jungang 
Published: January 2003

AbstractPoly(MMA‐ran‐St) samples were synthesized under monomer‐starved conditions (drop feeding method) by emulsion copolymerization. Their thermostability was determined by thermogravimetric analysis. The glass transition temperature (Tg) of the copolymers was determined by differential scanning calorimetry (DSC) and torsional braid analysis (TBA). The results showed that the MMA–St copolymers exhibit an asymmetric Tg versus composition curve, which could not be interpreted by Johnston's equation, taking the different contributions of the diads to the Tg of the copolymer into consideration. A new sequence distribution equation taking into account the different contributions of the triads was proposed to predict the copolymer Tg. The new equation fitted the experimental data exactly. The Tg determined by torsional braid analysis (TBA) is higher than the one determined by DSC, but the difference is not constant. The rheological behaviour of the copolymers was also studied and TgTBA‐TgDSC increased with the increasing flow index of the copolymer.© 2003 Society of Chemical Industry
Preparation and blood compatibility of phosphorylcholine‐bonded O‐butyrylchitosan
Authors: Zhu Aiping , Shan Bing , Yuan Youling , Shen Jian 
Published: January 2003

Abstract2‐Methacryloyloxyethyl phosphorylcholine (MPCE) was synthesized using phosphorus trichloride, ethylene glycol, 2‐hydroxyethyl methacrylate and triethylamine, and then used in the preparation of O‐butyrylchitosan‐bonded MPCE (MPCE–BCS) by Michael addition of MPCE to amino groups of O‐butyrylchitosan. The structures of MPCE and MPCE–BCS were characterized by FTIR and 1H NMR. The blood‐compatibility of MPCE–BCS was evaluated by means of blood clotting and platelet adhesion assays. The blood‐clotting assay indicated that O‐butyrylchitosan was haemocompatible. Both the blood‐clotting assay and platelet adhesion assay confirmed that MPCE–BCS had excellent antithrombogenicity.© 2003 Society of Chemical Industry
Study by thermal analysis of composites prepared from silica gel, furfuryl alcohol and acetaldehyde
Authors: García Teresita de la C , Gómez Maria R , Martínez Ricardo , Alonso Cristina 
Published: January 2003

AbstractComposites from furfuryl alcohol, acetaldehyde and silica gel were prepared with trifluoracetic acid as a catalyst. The composites were studied by TGA and DSC. The TGA results showed three main losses of weight, the first of which was ascribed to water. The percentage of polymer in the composites reached a limit value, independently of the ratio of furfuryl alcohol/acetaldehyde used. The layer of polymer that covers the silica was not completely cross‐linked. The composites contain soluble oligomers with 97: M
n < 580 g mol−1, that could be extracted with THF. The soluble fraction of composites prepared from mixtures of furfurylic alcohol and acetaldehyde decreased as the proportion of the acetaldehyde increased. The DSC of the samples indicated a Tg between −8 and −15 °C that disappeared after an extraction with THF. The DSC of the oligomers removed showed a possible Tg at 13 °C and an exothermic peak between 70 and 170 °C which corresponded to an enthalpy of 326.1 J g−1.© 2003 Society of Chemical Industry