bluuebunny/crossref_metadata_2025_split huggingface dataset:
Mise au point et caracterisation de mousses syntactiques
Authors: Lelu André , Fonblanc Gilles , Besson Jean‐Marc , Filliatre Claude , Daviaud Raymond 
Published: March 2011

AbstractSyntactic foams are manufactured to provide buoyancy to submarine devices. Last investigations were realized to study new syntactic foams which can be employed until six thousand meters deep. The syntactic materials made by S.N.P.E. are used mainly to buoy submarine devices and so, have to withstand very high pressures. So their components have to be made of high performance elements, thus, we employ epoxy matrices who possess low viscosity for wetting and casting easier. Fillers are glass microspheres, the average diameter of which are in the range of 50 to 100 μm. In order to use syntactic materials for this application the thermal and mechanical behaviour of some syntactic foams was characterized. We show some results of the syntactic foams. An other group of tests has been done in order to study the damage of the materials during an increase of the hydrostatic pressure. These tests have been conducted in a qualitative way in order to show the different eventual damage mechanisms. Also in the future syntactic materials have common interests with structural composite materials, hence we can assess their importance in the future, particularly in submarine projects.
Vieillissement hygrothermique de composites a matrice psp etude cinetique, spectroscopique et mecanique
Authors: Guetta B. , Bunsell A. R. 
Published: March 2011

AbstractThe objective of this study was the evaluation of the chemical structure and mechanical characteristics of composites in a poly(styrylpyridine) matrix, hygrothermically aged (from rel. humidity of 0% at the immersion at 40, 70 and 90°C), and some of them treated during the absorption at temp, cycles of 150 and 250°C. The following results were obtained: 1) The mechanism of absorption follows several irreversible steps during which hydrolysis of the resin takes place, as shown by IR and NMR spectroscopy. 2) A long term degradation of the material takes place at temp, cycles of 250°C. 3) A decrease in the mechanical characteristics of saturated materials was observed at 250°C.
Etude rar D.S.C. de la cristallisation non isotherme de matrices PA66 en presence de fibres de verre
Authors: Chabert Bernard , Chauchard Jacques , Cinquin Jacques 
Published: March 2011

AbstractNon isothermal crystallization of Polyamide 66 is studied by differential scanning calorimetry (DSC). OZAWA's theory has been successfully applied to the crystallization of the polymer with or without nucleating agents.Whith glass fibers, a non‐appreciable alteration of the crystalline structure has been noticed, but the over‐all speed of crystallization is essentially due to the role of glass fibers as nucléation agents (phase of germination). At the end of the transformation process, fibers constrict the expansion of the sphérolites and clearly decrease the over‐all speed of crystallization.
Endommagement par EAU D'UN composite epoxy‐microbulles de verre
Authors: Lataillade J. L. , Aragao E. , Hosten B. , Karaouzéne F. , Fonblanc G. , Derouault J. , Gruége F. , Daviaud R. , Filliatre C. 
Published: March 2011

AbstractHydrothermal effects on a composite material made of an epoxy resin and glass microspheres are investigated by means of infrared spectroscopy, ultrasonic techniques, and toughness measurements.It is shown that there exists a critical value of the relative weight amount beyond which the toughness increases‐due to the plastification of the matrix ‐ and above which it decreases because of a degradation of the interface. This value is reached for a duration at which a second site for the water in the matrix itself appears.
Modelisation de la reaction chimique de durcissement d'un systeme epoxy
Authors: Ancelle J. , Attias A. J. , Bloch B. , Lauprêctre F. , Monnerie L. 
Published: March 2011

AbstractChemical, as well as spectroscopical methods, were used to try to describe, as quantitatively as possible, the different kinds of chemical bonds constituting the network of a cured epoxy matrix, the tgmda/ DDS system. The chemical approach consisted, on the one hand, in synthesizing model compounds; on the other hand, model reactions from diepoxy and amino compounds were followed by chemical, chromatographical and spectroscopical analysis, in order to correlate structure of the products with reactivity of the starting molecules. Spectroscopical method, which was found most useful for this resin system, is solid state 13C CP/MAS NMR spectroscopy. As the spectra were not directly interpretable, because consisting largely of broad, bad‐resolved peaks, the aliphatic carbon region was decomposed into elementary lines. Structural assignments of the latter were made by using the solution state 13C NMR data of model compounds. On account of the anticipated mechanisms, 85 % of the aliphatic carbons could be identified and quantified.
Mise en evidence des phenomenes de gelification dans les systemes dgeba et TGMDA‐DDS par chromatography gazeuse inverse et methodes rheologique et de viscosimetrie
Authors: Grenier‐Loustalot Marie‐Florence , Mouline Ghita , Grenier Philippe , Serrano Daniel , Harran Daniel , Horny Patrick 
Published: March 2011

AbstractWe have used three physicochemical methods, reverse phase gas chromatography, Calvet microcalorimetry and rheology to examine the kinetics of isothermal cross‐linking in the polycondensation of epoxy‐prepolymers with aromatic amines.Gas chromatography results further define those obtained with gel time meter and rheological methods, and furnish not only a “gel point” but also a “gelling zone” for the two systems investigated.
Etude d'une resine epoxy chargee avec un noir de carbone
Authors: Fourche G. , Lafeychine L. , Carmona F. 
Published: March 2011

AbstractWe studied the electrical conductivity σ and the glass transition temperature Tg of an epoxy resin filled with a carbon black. It could be shown that σ and Tg depend on the volume concentration of carbon black and that the concentration dependence of Tg is sensitive to the thermal conditions of polymerization.
Influence des substituants du cycle benzenique sur la reactivite et les chemins reactionnels des monomeres C6H5‐N(EPOXY)2 avec des amines aromatiques
Authors: Grenier‐Loustalot Marie‐Florence , Orozco Laurence , Grenier Philippe 
Published: March 2011

AbstractThe course of model reactions of resins containing N‐(epoxy)2 groups with an aromatic amine was followed by measurements and high resolution 13C NMR spectroscopy in the liquid state. A reaction mechanism and a kinetic model are proposed according to the structure of the resins.
The patients' perception of prodromal symptoms before the initial diagnosis of Parkinson's disease
Authors: Gaenslen Alexandra , Swid Irene , Liepelt‐Scarfone Inga , Godau Jana , Berg Daniela 
Published: March 2011

AbstractBackground:Before the occurrence of motor symptoms permits the clinical diagnosis of Parkinson's disease (PD), about or even more than 50% of the dopaminergic neurons of the substantia nigra have degenerated. This time be called the prodromal phase of PD.Objective:To evaluate the time span from onset of first prodromal symptoms to the initial diagnosis of PD as well as the order of symptom occurrence.Methods:Retrospective study of 93 consecutively interviewed PD patients without dementia and 93 sex and age matched controls free of neurodegenerative disorders. A standardized in‐house telephone worksheet assessing 19 nonmotor and six early motor signs was used.Results:A total of 98.8% of all patients interviewed reported to have experienced prodromal symptoms prior to receiving the initial diagnosis of PD. Patients noticed an average of 7.6 different symptoms during this time interval. The mean time span between the recalled onset of any one symptom and PD diagnosis was 10.2 years. In both groups, the course of prodromal sign onset was associated with early neuropathological disease stages proposed by Braak.Outlook:These retrospectively gathered data confirm the existence of a long prodromal phase for PD that is consistent with neuropathological staging. A standardized questionnaire assessing such early symptoms may be helpful in identifying subjects at high risk for PD while they are still in the prodromal phase of the disorder. © 2011 Movement Disorder Society
Meta‐analysis of the comparative efficacy and safety of adjuvant treatment to levodopa in later Parkinson's disease
Authors: Stowe Rebecca , Ives Natalie , Clarke Carl E. , Handley Kelly , Furmston Alexandra , Deane Katherine , van Hilten J.J. , Wheatley Keith , Gray Richard 
Published: March 2011

AbstractBackground:Levodopa initially provides good symptomatic control of the symptoms of Parkinson's disease, but motor complications often develop after long‐term use. Other classes of antiparkinsonian drugs including dopamine agonists, catechol‐O‐methyl transferase inhibitors, or monoamine oxidase type B inhibitors are then added as adjuvant therapy. It is unclear whether one class of drug is more effective than another. This meta‐analysis evaluates the comparative benefits and risks of these agents as adjuvant treatment in Parkinson's disease patients with motor complications.Methods:A systematic review of the literature from 1966 to the end of June 2010 was conducted to identify randomized trials involving a dopamine agonist, catechol‐O‐methyl transferase inhibitor, or monoamine oxidase type B inhibitor versus placebo, as adjuvant to levodopa therapy.Results:Forty‐five trials involving nearly 9,000 participants were included. The meta‐analysis confirms reports from individual trials that compared with placebo, adjuvant therapy significantly reduces patient off‐time and levodopa dose, with improved symptom severity scores (e.g., Unified Parkinson's Disease Rating Scale). However, dyskinesia and numerous other side effects are increased with adjuvant therapy. Few randomized comparisons between drugs have been undertaken, but indirect comparisons suggest that dopamine agonist therapy may be more effective than catechol‐O‐methyl transferase inhibitor and monoamine oxidase type B inhibitor therapy, which have comparable efficacy. No differences between drugs within each class were observed other than the catechol‐O‐methyl transferase inhibitor tolcapone appearing more efficacious than entacapone.Discussion:This meta‐analysis highlights the need for direct head‐to‐head randomized trials to assess the impact of adjuvant therapy on patient‐rated quality of life and health economic outcomes. © 2011 Movement Disorder Society
Comparative neuropsychological profile of pathological gambling, hypersexuality, and compulsive eating in Parkinson's disease
Authors: Vitale Carmine , Santangelo Gabriella , Trojano Luigi , Verde Francesca , Rocco Mariangela , Grossi Dario , Barone Paolo 
Published: March 2011

AbstractBackground: Impulse control disorders (ICDs), in particular pathological gambling, hypersexuality, and compulsive eating, are being increasingly identified in Parkinson's disease (PD) patients. Pathological gambling has been associated with frontal/executive dysfunctions, whereas hypersexuality and compulsive eating, and their relation with cognitive dysfunctions, have not been investigated in PD.Methods: We investigated cognitive correlates underpinning pathological gambling, hypersexuality, and compulsive eating in PD. PD outpatients were screened for pathological gambling, hypersexuality, and compulsive eating. Based on clinical criteria, we identified 13 patients with hypersexuality, 12 with compulsive eating, 14 with pathological gambling, and 10 with multiple ICDs. Fourteen PD patients matched for age and education without ICDs served as controls. Clinical features and neuropsychiatric and neuropsychological functioning were assessed in the 5 groups.Results: Demographic, clinical, neuropsychiatric, and neurological aspects did not differ among groups. All 4 groups of ICD patients were impaired on tasks exploring spatial‐planning and set‐shifting tasks compared with the controls. The main difference among patients with pathological gambling, hypersexuality, and compulsive eating was that patients with hypersexuality were more impaired on the Stroop test than patients with pathological gambling. Individuals with hypersexuality, compulsive eating, and multiple ICDs performed worse on verbal learning and memory tests than did patients with pathological gambling.Discussion: ICDs are associated with impaired cognitive functions; the severity of impairment decreased in the order multiple ICDs and hypersexuality > compulsive eating > pathological gambling. Our findings support the idea that hypersexuality is associated with prefrontal and memory dysfunctions, whereas pathological gambling seems to be related only to frontal dysfunction. © 2011 Movement Disorder Society
An item response analysis of the motor and behavioral subscales of the unified Huntington's disease rating scale in huntington disease gene expansion carriers
Authors: Vaccarino Anthony L. , Anderson Karen , Borowsky Beth , Duff Kevin , Giuliano Joseph , Guttman Mark , Ho Aileen K. , Orth Michael , Paulsen Jane S. , Sills Terrence , van Kammen Daniel P. , Evans Kenneth R. ,   PREDICT‐HD and REGISTRY Investigators Coordinators
Published: March 2011

AbstractAlthough the Unified Huntington's Disease Rating Scale (UHDRS) is widely used in the assessment of Huntington disease (HD), the ability of individual items to discriminate individual differences in motor or behavioral manifestations has not been extensively studied in HD gene expansion carriers without a motor‐defined clinical diagnosis (ie, prodromal‐HD or prHD). To elucidate the relationship between scores on individual motor and behavioral UHDRS items and total score for each subscale, a nonparametric item response analysis was performed on retrospective data from 2 multicenter longitudinal studies. Motor and behavioral assessments were supplied for 737 prHD individuals with data from 2114 visits (PREDICT‐HD) and 686 HD individuals with data from 1482 visits (REGISTRY). Option characteristic curves were generated for UHDRS subscale items in relation to their subscale score. In prHD, overall severity of motor signs was low, and participants had scores of 2 or above on very few items. In HD, motor items that assessed ocular pursuit, saccade initiation, finger tapping, tandem walking, and to a lesser extent, saccade velocity, dysarthria, tongue protrusion, pronation/supination, Luria, bradykinesia, choreas, gait, and balance on the retropulsion test were found to discriminate individual differences across a broad range of motor severity. In prHD, depressed mood, anxiety, and irritable behavior demonstrated good discriminative properties. In HD, depressed mood demonstrated a good relationship with the overall behavioral score. These data suggest that at least some UHDRS items appear to have utility across a broad range of severity, although many items demonstrate problematic features. © 2011 Movement Disorder Society
Illusory misidentifications and cortical hypometabolism in Parkinson's disease
Authors: Ishioka Toshiyuki , Hirayama Kazumi , Hosokai Yoshiyuki , Takeda Atsushi , Suzuki Kyoko , Nishio Yoshiyuki , Sawada Yoichi , Takahashi Shoki , Fukuda Hiroshi , Itoyama Yasuto , Mori Etsuro 
Published: March 2011

AbstractIdiopathic Parkinson's disease (PD) is associated with documented impairments in various visual functions. However, there have been only a limited number of studies that have reported on the brain regions responsible for impairment of visual recognition in PD. In our study, we evaluated the performance of PD patients and 24 healthy controls on the Poppelreuter‐type overlapping figure identification test to investigate the impairment of visual recognition. We also measured the PD patients' resting cerebral glucose metabolism using 18F‐fluorodeoxyglucose positron emission tomography and investigated the relationship between the impairment of visual recognition and cortical hypometabolism. The PD patients had substantial and frequent illusory responses in the overlapping figure identification test, and their illusory misidentifications were correlated with hypometabolism in the visual cortices, including the right inferior temporal gyrus and the bilateral temporo‐parieto‐occipital junction. These findings suggest that PD patients have impaired visual recognition characterized by illusory misidentifications of visual stimuli, which could be attributed to dysfunction of the visual cortices. © 2011 Movement Disorder Society
MRI with zero echo time: Hard versus sweep pulse excitation
Authors: Weiger Markus , Pruessmann Klaas P. , Hennel Franciszek 
Published: March 2011

AbstractZero echo time can be obtained in MRI by performing radiofrequency (RF) excitation as well as acquisition in the presence of a constant gradient applied for purely frequency‐encoded, radial centre‐out k‐space encoding. In this approach, the spatially nonselective excitation must uniformly cover the full frequency bandwidth spanned by the readout gradient. This can be accomplished either by short, hard RF pulses or by pulses with a frequency sweep as used in the SWIFT (Sweep imaging with Fourier transform) method for improved performance at limited RF amplitudes. In this work, the two options are compared with respect to T2 sensitivity, signal‐to‐noise ratio (SNR), and SNR efficiency. In particular, the SNR implications of sweep excitation and of initial or periodical acquisition gaps required for transmit‐receive switching are investigated. It was found by simulations and experiments that, whereas equivalent in terms of T2 sensitivity, the two techniques differ in SNR performance. With ideal, ungapped simultaneous excitation and acquisition, the sweep approach would yield higher SNR throughout due to larger feasible flip angles. However, acquisition gapping is found to take a significant SNR toll related to a reduced acquisition duty cycle, rendering hard pulse excitation superior for sufficient RF amplitude and also in the short‐T2 limit. Magn Reson Med, 2011. © 2011 Wiley‐Liss, Inc.
Real‐time motion and B0 corrected single voxel spectroscopy using volumetric navigators
Authors: Hess Aaron T. , Dylan Tisdall M. , Andronesi Ovidiu C. , Meintjes Ernesta M. , van der Kouwe André J. W. 
Published: March 2011

AbstractIn population groups where head pose cannot be assumed to be constant during a magnetic resonance spectroscopy examination or in difficult‐to‐shim regions of the brain, real‐time volume of interest, frequency, and shim optimization may be necessary. We investigate the effect of pose change on the B0 homogeneity of a (2 cm)3 volume and observe typical first‐order shim changes of 1 μT/m per 1° rotation (chin down to up) in four different volumes of interest in a single volunteer. An echo planar imaging volume navigator was constructed to measure and apply in real‐time within each pulse repetition time: volume of interest positioning, frequency adjustment, and first‐order shim adjustment. This volume navigator is demonstrated in six healthy volunteers and achieved a mean linewidth of 4.4 Hz, similar to that obtained by manual shim adjustment of 4.9 Hz. Furthermore, this linewidth is maintained by the volume navigator at 4.9 Hz in the presence of pose change. By comparison, a mean linewidth of 7.5 Hz was observed, when no correction was applied. Magn Reson Med, 2011. © 2011 Wiley‐Liss, Inc.
Design and evaluation of an RF front‐end for 9.4 T human MRI
Authors: Shajan G. , Hoffmann Jens , Budde Juliane , Adriany Gregor , Ugurbil Kamil , Pohmann Rolf 
Published: March 2011

AbstractAt the field strength of 9.4 T, the highest field currently available for human MRI, the wavelength of the MR signals is significantly shorter than the size of the examined structures. Even more than at 7 T, constructive and destructive interferences cause strong inhomogeneities of the B1 field produced by a volume coil, causing shading over large parts of the image. Specialized radio frequency hardware and B1 management methods are required to obtain high‐quality images that take full advantage of the high field strength. Here, the design and characteristics of a radio frequency front‐end especially developed for proton imaging at 9.4 T are presented. In addition to a 16‐channel transceiver array coil, capable of volume transmit mode and independent signal reception, it consists of custom built low noise preamplifiers and TR switches. Destructive interference patterns were eliminated, in virtually the entire brain, using a simple in situ radio frequency phase shimming technique. After mapping the B profile of each transmit channel, a numerical algorithm was used to calculate the appropriate transmit phase offsets needed to obtain a homogeneous excitation field over a user defined region. Between two and three phase settings are necessary to obtain homogeneous images over the entire brain. Magn Reson Med, 2011. &&copy; 2011 Wiley‐Liss, Inc.
Ultrasound‐guided steroid injection to treat mild ulnar neuropathy at the elbow
Authors: Rampen Anneke J.J. , Wirtz Paul W. , Tavy Denes L.J. 
Published: March 2011

AbstractThere exists no “gold standard” in the treatment of ulnar neuropathy at the elbow (UNE). We treated 7 patients with mild UNE using a local steroid injection with ultrasonographic monitoring. At clinical follow‐up after 6 weeks, 4 patients had improved, 2 were stable, and 1 reported an increase in symptoms. Ultrasound‐guided steroid injection in mild UNE is safe and could be effective. Further investigation is needed to prove its efficacy. Muscle Nerve 44: 128–130, 2011.
Long‐term hepatic outcomes in survivors of stage 4S and 4 neuroblastoma in infancy
Authors: French Amy E. , Irwin Meredith S. , Navarro Oscar M. , Greenberg Mark , Nathan Paul C. 
Published: March 2011

AbstractBackgroundInfants with stage 4 and 4S neuroblastoma (NB) have a superior prognosis to older children. However, they often require intensive therapy including abdominal radiation. We aimed to investigate the long‐term hepatic outcomes in infants with stage 4S and 4 NB.MethodsWe reviewed the charts of 38 infants diagnosed with stage 4S and 4 NB between 1984 and 2002. We included only those with available follow‐up 5 years following diagnosis. We assessed hepatic imaging and function (transaminases, bilirubin, alkaline phosphatase) at all available time points from diagnosis. Abnormalities present at more than 5 years from diagnosis were considered persistent late changes.ResultsWe identified 15 stage 4S and 12 stage 4 patients. Twelve of 15 stage 4S patients had hepatic involvement at diagnosis, 8 of whom required abdominal radiation. Five of eight demonstrated late imaging changes. Two of four with hepatic metastases but no radiation demonstrated late imaging changes. The late imaging changes resolved over time and without intervention in 3/7 survivors. The persistent lesions included liver fibrosis (1) and focal nodular hyperplasia (FNH) (3). Five of 12 stage 4 NB patients had hepatic involvement at diagnosis; none required radiation or had late hepatic imaging changes.ConclusionsIn stage 4S NB, adverse hepatic effects are infrequent, may resolve over time, and occur with or without radiation. FNH should be considered in those with persistent late imaging changes. Adverse hepatic outcomes after liver involvement or radiation in infants with stage 4 NB rarely occur. Pediatr Blood Cancer 2012; 58: 283–288. © 2011 Wiley Periodicals, Inc.