bluuebunny/crossref_metadata_2025_split huggingface dataset:
Gait analysis in patients with Parkinson's disease and motor fluctuations: Influence of levodopa and comparison with other measures of motor function
Authors: O'Sullivan John D. , Said Catherine M. , Dillon Louise C. , Hoffman Marion , Hughes Andrew J. 
Published: May 2005

AbstractAlthough clinical rating scales and simple timed tests of motor function are widely used to assess motor response to therapy, gait analysis may provide an alternative measure of this response. We studied 15 patients with PD complicated by motor fluctuations, first to determine changes in temporal and spatial gait parameters following levodopa, secondly to assess the stability of repeated gait measures and timed tests in “off” and “on” states, and thirdly to determine the use of gait analysis in the assessment of the dopaminergic response. Gait analysis (velocity, stride length, cadence, and double limb support), clinical rating scales (modified Webster scale and Hoehn and Yahr stage), and timed tests of motor function (hand tapping and stand‐walk‐sit time) were performed before (“off”) and after (“on”) a levodopa challenge. Stride length and gait velocity increased following medication whereas cadence and double limb support did not. Most gait measures and the stand‐walk‐sit time were stable over three consecutive trials in both “off” and “on” states. Of the gait measures, only cadence in the “off” state changed significantly whereas the tapping count improved with repeated trials in both “off” and “on” states. Changes in stride length, gait velocity, and tapping count following levodopa correlated with changes in clinical rating scales following treatment. Measurement of gait parameters provides a reliable, objective alternative to rating scales and timed tests in assessing the dopaminergic response in patients with PD and motor fluctuations.
Treatment of tremor in Parkinson's disease by subthalamic nucleus stimulation
Authors: Krack P. , Benazzouz Abdelhamid , Pollak Pierre , Limousin Patricia , Piallat Brigitte , Hoffmann Dominique , Xie Jing , Benabid Alim‐Louis 
Published: May 2005

AbstractThe recent resurgent interest in functional surgery for the treatment of Parkinson's disease (PD) has focused on the effects on akinesia and levodopa‐induced dyskinesia. Stimulation of the subthalamic nucleus (STN) improves akinesia and rigidity but its effects on tremor have not been studied. The objective of this study was to assess the efficacy of STN stimulation on tremor in patients with the complete parkinsonian triad with motor fluctuations. Of 27 consecutive patients with STN stimulation (26 bilateral), 15 exhibited tremor rated at least 2/4 according to item 20 (rest tremor) of the Unified Parkinson's Disease Rating Scale (UPDRS) in at least one limb. The mean preoperative tremor score was 11.3 ± 5.6 in off‐drug and 1.2 ± 2.4 in on‐drug conditions. The postoperative tremor scores at the last follow up (from 1–12 months) were 2.2 ± 2.2 off‐drug/on‐stimulation and 0.2 ± 0.4 on‐drug/on‐stimulation. Both rest and action tremors were improved in all patients. The UPDRS tremor score was reduced by 80%, rigidity score by 65%, and akinesia score by 51% on average. For the three symptoms, the stimulation effect was close to that induced before surgery by a suprathreshold dose of levodopa given in the morning. STN stimulation can be considered an interesting alternative to thalamic or internal pallidal surgery even in PD patients with severe high‐amplitude tremor. In keeping with electrophysiological data in monkeys rendered parkinsonian by MPTP injections, our results emphasize the importance of the oscillation of a neuronal loop involving the STN in the pathophysiology of parkinsonian tremor.
Neurophysiological abnormalities in the westphal variant of Huntington's disease
Authors: Töpper Rudolf , Schwarz Michael , Lange Herwig W. , Hefter Harald , Noth Johannes 
Published: May 2005

AbstractThe Westphal variant of Huntington's disease (HD) is a distinct clinical entity of HD characterized by a rigid‐hypokinetic syndrome and is often associated with a juvenile onset of disease. Definite genetic differences between the subtypes of HD have not been delineated so far. Here we present the results of a battery of neurophysiological tests including somatosensory‐evoked potentials, blink reflexes, longlatency reflexes, and measurement of saccadic velocities in a Westphal HD patient. Although quantitative assessment of his motor performance showed a severe hypokinetic syndrome resembling Parkinson's disease, the results of somatosensoryevoked potentials and blink reflexes were indistinguishable from results obtained in hyperkinetic HD patients. Longlatency reflexes, however, which are typically absent in hyperkinetic HD patients, were retained in this patient. It is concluded that neurophysiology in HD patients is not a mere reflection of the patient's symptomatology but can give insight into the underlying pathophysiological process.
Tardive blepharospasm
Authors: Sachdev Perminder 
Published: May 2005

AbstractI report on five patients with tardive blepharospasm seen in a movement disorders clinic, out of 25 tardive dystonia patients. They were young (aged 25–50 yrs); four were men and three had a schizophrenic disorder. The onset was gradual while on maintenance neuroleptics in four and on withdrawal in the fifth. There were no significant antecedent events precipitating the disorder. The disorder was bilateral but asymmetric in two cases. Dyskinetic blinking was often an initial feature and tended to persist after the resolution of the blepharospasm. Orolingual dyskinesia was present in one case and tardive akathisia in two other cases. The symptoms fluctuated in severity with a number of exacerbating and relieving factors. Reduction of neuroleptic dose led to improvement with complete reversal in one of two patients who could be withdrawn off neuroleptic medication. These reports suggest that TB, although uncommon, can be a disabling disorder that may improve considerably with the cessation or dose reduction of the neuroleptic drugs. Its treatment and longitudinal course should be further examined.
Gait in patients with cerebellar ataxia
Authors: Palliyath Sarala , Hallett Mark , Thomas Sherry L. , Lebiedowska Maria K. 
Published: May 2005

AbstractThe gait pattern in 10 patients with cerebellar degenerations was studied and the results were compared with 10 matched normal subjects, seeking the principal patterns in this disorder. Gait at natural speed was studied in a biomechanics laboratory using a video‐based kinematic data acquisition system for measuring body movements. Patients showed a reduced step and stride length with a trend to reduced cadence. Heel off time, toe off time, and time of peak flexion of the knee in swing were all delayed. Range of motion of ankle, knee, and hip were all reduced, but only ankle range of motion reached significance. Multijoint coordination was impaired, as indicated by a relatively greater delay of plantar flexion of the ankle compared with flexion of the knee and a relatively late knee flexion compared with hip flexion at the onset of swing. The patients also showed increased variability of almost all measures. Although some of the deviations from normal were simply the result of slowness of walking, the gait pattern of patients with cerebellar degeneration shows incoordination similar to that previously described for their multijoint limb motion.
EPR study of bridgehead‐substituted bicyclo [2.2.2]oct‐1‐yl and triptycyl radicals
Authors: Binmore Gavin T. , Walton John C. , Adcock William , Clark Christopher I. , Kristic Alexander R. 
Published: May 2005

Abstract4‐Substituted bicyclo [2.2.2] oct‐1‐yl radicals were generated by bromine atom abstraction from the corresponding 1‐bromobicyclo [2.2.2] octanes and observed in solution by EPR spectroscopy. A tendency towards lower a(Hβ) and a(Hγ) values for inductively electron‐withdrawing substituents such as OMe and F and towards higher values for electron‐releasing groups such as Me3Ge and Me3Sn was observed. For a series of bridgehead radicals, the hfs of β‐hydrogens showed a monotonic increase as the extent of flattening at the bridgehead increased. The EPR data indicated that 4‐substitutents exercised a significant effect at the radical centre, mainly by a through‐bond mechanism. 10‐Substituted triptycl radicals were generated in a similar way but showed no hfs from magnetic nuclei of the substituents. Thus, the triptycyl cage transmitted spin density much less effectively than the bicyclo [2.2.2] octyl cage. Bicyclo [2.2.2] oct‐1‐yl and adamant‐1‐yl radicals added to benzene, tert‐butylbenzene and 1,3‐di‐tert‐butylbenzene to give cyclohexadienyl radicals which were characterized by EPR spectroscopy. Triptycyl radicals and strained bridgehead radicals such as cubyl and bicyclo [1.1.1] pent‐1‐yl gave no detectable cyclohexadienyl radicals under similar conditions. Both bicyclo [2.2.2] oct‐1‐yl and adamant‐1‐yl radicals generated in tert‐butylbenzene showed exclusive meta addition with formation of the corresponding 1‐polycyclo‐3‐tert‐butylcyclohexadienyl radical.
ESR and ENDOR study on the radical ions of two non—alternant hydrocarbons: 1,3,5,7‐tetra‐tert‐butyl‐s‐indacene and 2,7‐di‐tert‐butyldicyclopenta [a,e] cyclooctene
Authors: Bachmann Rainer , Gerson Fabian , Gescheidt Georg , Hafner Klaus 
Published: May 2005

AbstractThe radical anions and radical cations of two alkyl‐substituted non‐alternant hydrocarbons, 1,3,5,7‐tetra‐tert‐butyl‐s‐indacene and 2,7‐di‐tert‐butyldicyclopenta [a,e] cyclooctene, were characterized by their proton coupling constants with the use of ESR and, in part, ENDOR spectroscopy. Considering the unusual electronic structures of the π‐systems in question, these values agree fairly well with those predicted by simple MO theory. Also reported are the proton hyperfine data for the radical ions of the likewise alkyl‐substituted non‐alternant 8,16‐diisopropyl‐s‐indaceno [1,2,3‐cd:5,6,7‐c′ d′] diphenalene.
EPR study of alkali metal atoms in hydrocarbon matrices
Authors: Jones Ruth , Howard J. Anthony , Joly Helen A. , Edwards Peter P. , Singer Richard J. 
Published: May 2005

AbstractA rotating cryostat was used to trap the Group 1 metal atoms in adamantane and cyclohexane matrices at 77 K. Electron paramagnetic resonance spectra of matrix‐isolated atoms were obtained in adamantane at X‐ and Q‐band frequencies. The magnetic parameters were calculated from exact solutions of the Breit‐Rabi equation and compared with values in the gas phase and in rare gas matrices. The EPR spectra show no evidence for g and/or hyperfine anisotropy. Consequently, there is no evidence for the dipolar state of these atoms. Furthermore, trimers, pentamers and/or septamers are not formed from Rb and Cs under experimental conditions that have led to the formation of Li3, Li5, Na3 and K7. Group 1 atoms in a solid cyclohexane matrix give only colloidal metal particles with an average diameter of less than 102 Å.
Evaluation of nitroxides for the study of myocardial metabolism and oxygenation
Authors: Kuppusamy Periannan , Wang Penghai , Zweier Jay L. 
Published: May 2005

AbstractElectron paramagnetic resonance spectroscopy at the L‐band (1.2 GHz) was used to investigate the redox metabolism and oxygenation within ischemic rat hearts loaded with a variety of six‐ and five‐membered carbocyclic nitroxide spin labels. Both cardiopleged and non‐cardiopleged hearts were studied at room temperature and at physiological temperatures. The results indicate that nitroxides that have greater intracellular partitioning are reduced faster than those that are extracellular. In addition, the six‐membered rings are metabolized much faster than the five‐membered rings. Increased nitroxide radical metabolism was observed in non‐cardiopleged compared with cardiopleged hearts. The oxygen utilization in the ischemic hearts was studied by using the oxygen‐dependent broadening of the nitroxide signals that occurs due to Heisenberg spin exchange. These structurally different nitroxides were evaluated for their sensitivity and suitability as probes of myocardial redox metabolism and oxygenation in the heart.
Spin trapping chemistry of acyl radicals
Authors: Janzen Edward G. , Davis Edward R. , DuBose Coit M. 
Published: May 2005

AbstractThe EPR spectra of a variety of different acyl radical adducts of PBN (C‐phenyl N‐tert‐butyl nitrone) and MNP (2‐methyl‐2‐nitrosopropane) were measured and their hyperfine splitting constants determined. Included are benzoyl, acetyl and other alkylacyl, alkoxyacyl, aminoacyl and alkylaminoacyl adducts. All examples gave relatively large β‐hydrogen hyperfine splittings ranging from 2.71 to 5.93 G in the PBN spin adducts. Long‐range hyperfine splitting was found to both nitrogen and amino‐hydrogen atoms in the aminoacyl adducts, indicating specific preferred conformations of the spin adducts. The MNP adducts have the well known 7‐8 G nitrogen hyperfine splitting with little else. The existence of hydrogen atom abstraction from benzaldehyde by nitroxides was established, indicating that nitroxides cannot be considered as inert reagents when sent to probe systems containing aldehydes. For example, the EPR signal due to a nitronyl nitroxide was rapidly quenched in the presence of benzaldehyde in benzene. Also, a surprising increase in intensity of benzoyl PBN adduct was noted after photolysis when the light was turned off. Double acyl adduct formation is proposed.
Rubber‐modified epoxies: III. Influence of the rubber molecular weight on the phase separation process
Authors: Chen Dong , Pascault Jean Pierre , Sautereau Henry , Ruseckaite Roxane A. , Williams Roberto J. J. 
Published: May 2005

AbstractThe effect of varying the rubber molecular weight on the reaction induced phase separation taking place in rubber‐modified epoxies is reported. Three butadiene–acrylonitrile copolymers with number‐average molecular weights of 2030, 3600 and 6050 g mol−1 were used. The thermosetting polymer was an epoxy based on diglycidylether of bisphenol‐A cured with a cycloaliphatic diamine. Increasing the rubber molecular weight showed the following effects: (i) a decrease in the conversion at the cloud point; (ii) a corresponding decrease in the viscosity at the cloud point; (iii) a primary morphology of a low concentration of particles with a large size; (iv) a more complete segregation of the rubber from the matrix leading to a smaller decrease of the glass transition temperature of the system; (v) a decrease in the toughening. The Flory–Huggins lattice model may be used as a simple approximation to describe the phase separation process when varying the rubber molecular weight.
Rubber‐modified epoxies: IV. Role of chain ends on the morphologies and properties
Authors: Chen Dong , Pascault Jean Pierre , Sautereau Henry 
Published: May 2005

AbstractFour reactive liquid rubbers with different end‐groups but the same main chain (carboxyl‐, epoxy‐, amino‐terminated and non‐functional butadiene–acrylonitrile random copolymers) were employed in the same epoxy system, the diglycidyl ether of bisphenol A and 4,4′‐diamino‐3,3′‐dimethyldicyclohexyl methane cured at 50°C. The effects of the end‐groups of the liquid rubber on the morphology, phase compositions, sub‐structure inside the particles, interface between the phases and the mechanical properties were determined. The effects were related to the reactivity and the miscibility of the additive.
DSC studies on states of water in crosslinked poly(methyl methacrylate‐co‐n‐vinyl‐2‐pyrrolidone) hydrogels
Authors: Ahmad Mansor B. , Huglin Malcolm B. 
Published: May 2005

AbstractMixtures of methyl methacrylate (MMA) with N‐vinyl‐2‐pyrrolidone (VP) of various composition in the presence of fixed concentration of ethylene glycol dimethacrylate (EDMA) have been copolymerized to 100% conversion by γ‐irradiation. The resultant solid xerogels were swollen in water to yield hydrogels of equilibrium water contents ranging from 15 to 76wt%. The state of water in the poly(MMA‐co‐VP) hydrogels has been studied by differential scanning calorimetry (DSC) and the percentages of free freezing, freezable bound and nonfreezing water were found to vary with the xerogel composition, i.e. the degree of hydration of the hydrogels. At low equilibrium swelling, most of the water exists as a non‐freezing type, whereas at higher equilibrium swelling the majority of water exists as free freezing water. The maximum number of non‐freezing water molecules per VP unit in the hydrogel is about 7.5.
DSC analysis of ethylene/1‐butene copolymers obtained with different ziegler–natta catalysts
Authors: Bruni Cosimo , Pracella Mariano , Masi Francesco , Menconi Francesco , Ciardelli Francesco 
Published: May 2005

AbstractThe crystallization and melting behaviour of two sets of ethylene/1‐butene copolymers have been analysed by DSC. The samples, with comonomer content in the range from 0 to 21.5 mol%, were obtained by industrial processes using both Mg/Ti‐based catalyst systems. The composition dependences of melting and crystallization temperatures were found to be strictly affected by the catalyst type. Moreover, logarithmic plots of the melting and crystallization enthalpy as a function of the ethylene content (mol%) in the copolymers fitted linear relationships whose slopes have been related to the critical sequence length of crystallizable ethylene units, depending on the catalytic system. These results are compared with those reported in the literature for ethylene/1‐butene copolymers synthesized by other catalysts and are accounted for by a different distribution of the comonomer units in the macromolecules of the two sets of samples.
Molecular motions in poly(vinyl acetate) revisited. A thermally stimulated current study
Authors: Dias Ana B. , Correia Natália T. , Moura‐Ramos Joaquim J. , Fernandes Anabela C. 
Published: May 2005

AbstractThe dipolar relaxation mechanisms in poly(vinyl acetate) have been studied in detail using the technique of thermally stimulated currents. The papers published in the literature about this subject are very contradictory, particularly with respect to the assignment of the observed discharges to the corresponding motions at the molecular level. This work aims at clarifying these problems. We detected and characterised three different relaxation mechanisms: (1) a low temperature one (around −140°C) which was attributed to local internal rotations in the acetate side‐groups; (2) a relaxation whose maximum occurs at 42°C, which corresponds to the glass transition relaxation, and shows a compensation behaviour; (3) an upper glass transition relaxation whose maximum appears at 87°C and was attributed to a liquid‐liquid transition. These assignments have been made on the basis of the analysis of the behaviour of the samples when submitted to different thermal and electrical treatments.
Kinetic behaviour of adsorption of gelatin at solid–liquid interface
Authors: Bajpai A. K. 
Published: May 2005

AbstractThe kinetics of adsorption of gelatin from its aqueous solution on to silica has been studied at room temperature. The adsorption isotherms were found to be of the Langmuir type. From the adsorption isotherms, the adsorption coefficient, surface coverage and rate constants for adsorption and desorption were evaluated. The rate of adsorption was found to be maximum at the isoelectric point of gelatin and decreased with increase in pH of the adsorption medium. The increased ionic strength of the medium also caused an increase in the rate and amount of adsorption.
Effect of accelerated aging on the properties of some writing paper sheets
Authors: El‐Din Nabil M. Safy , Fahmy A. M. 
Published: May 2005

AbstractWriting papers made from kraft softwood pulp and bagasse dissolving pulp were subjected to thermal aging for different time intervals (24, 48, 72, 96 and 120h) and the resulting changes in their chemical, physical and submicroscopic properties were investigated. The crystallinity changes in these pulps during thermal aging were studied by X‐ray diffractograms. The carboxyl content of the kraft softwood pulp increased with time of thermal aging up to 96h and then decreased with increasing aging time, while the carboxyl content of bagasse dissolving pulp increased during thermal aging up to 72h and then decreased after this time. The crystallinity of kraft softwood pulp increased gradually during thermal aging. However, in the case of bagasse dissolving pulp the crystallinity increased up to 72h and then decreased. All pulps were characterized by a reduction in the degree of whiteness and chain depolymerization during the time of thermal aging.
Morphology of fibers from poly(phenylene sulfide) and its liquid crystallinity
Authors: Xiao Weiwei , Xu Xi 
Published: May 2005

AbstractFresh poly(phenylene sulfide) (PPS) fibers have pleated surface morphology and banded texture. These structural features are similar to those of poly(phenylene terephthalamide) fiber (Kevlar), whereas some unique morphologies were observed for the long‐term stored PPS fibers, which have not been found with liquid crystalline polymer fibers including Kevlar. The long‐term stored PPS fibers show a decreased Tg and a decreased onset temperature of melting, compared with their fresh counterparts, which is attributed to stress relaxation and resulting disorientation in the amorphous region of the fibers. Combination of the observed typical morphologies with polarized optical microscopy and X‐ray diffraction analysis suggests that PPS possesses liquid crystalline nature.
Investigation of the molecular transport of aliphatic and aromatic esters into engineering polymer membranes
Authors: Aminabhavi Tejraj M. , Munnolli Ravindra S. 
Published: May 2005

AbstractMolecular transport as manifested by sorption and diffusion of organic esters into engineering polymer membranes, viz. nitrile butadiene rubber, styrene butadiene rubber, ethylene propylene diene terpolymer, neoprene and natural rubber, has been investigated in the temperature range 25–60°C by the sorption gravimetric technique. The sorption equilibrium for ethylene propylene diene terpolymer was lower than those of the other polymers with all the liquids. Diffusion and permeation coefficients were obtained for the polymer‐solvent systems and these follow Arrhenius type behaviour in the temperature range investigated.
Copolymerization of zinc acrylate with acrylonitrile initiated by As2S3–styrene complex
Authors: Agrawal B. P. , Srivastava A. K. 
Published: May 2005

AbstractRadical copolymerization of zinc acrylate (ZnA2) with acrylonitrile (AN), initiated by As2S3–styrene complex(I), in dimethyl Sulphoxide (DMSO) at 90 ± 0.1°C for 1.0h under inert atmosphere, yields non‐alternating copolymers. The kinetic expression is Rp ∝ [I]0.33 [ZnA2]0.25 [AN]0.44, i.e. the system follows non‐ideal kinetics, which is due to primary radical termination as well as degradative chain transfer reactions. The values for activation energy (E) and k2p/kt are 128kJ mol−1 and 8.57 × 10−7 litre mol−1 s−1, respectively. Thermal stability, solubility in different solvents, and IR and NMR spectra have been evaluated.