bluuebunny/crossref_metadata_2025_split huggingface dataset:
Spherical MgCl2 Supported Iron Catalyst for Ethylene Polymerization: Effect of the Preparation Procedure on Catalyst Activity and the Morphology of Polyethylene Particles
Authors: Huang Rubin , Liu Dongbing , Wang Shibo , Mao Bingquan 
Published: April 2004

AbstractSummary: A new procedure was developed to support [(ArNC(Me))2C5H3N]FeCl2 (Ar2,4,6‐trimethylphenyl) on spherical MgCl2 for ethylene polymerization. The resultant catalysts showed ten times higher activity of the corresponding catalyst in homogeneous catalysis. The morphologies of polyethylene particles strongly depended on supported catalyst preparation procedure and polymerization conditions. In addition, the GPC measurements showed bimodal polyethylene for the homogeneous polymerization while mono‐modal polyethylene of those supported catalysts.EDX Line Scan analysis of the catalyst SMSIC‐1 regarding the aluminium and iron distribution in the volume (25 kV accelerating voltage, magnification 1 500).imageEDX Line Scan analysis of the catalyst SMSIC‐1 regarding the aluminium and iron distribution in the volume (25 kV accelerating voltage, magnification 1 500).
Rhythmic movement disorder and cyclic alternating pattern during sleep: A video‐polysomnographic study in a 9‐year‐old boy
Authors: Manni Raffaele , Terzaghi Michele , Sartori Ivana , Veggiotti Pierangelo , Parrino Liborio 
Published: April 2004

AbstractWe report on polysomnographic findings in a 9‐year‐old boy affected by rhythmic movement disorder. The subject's rhythmic movements were found to be intimately linked to unstable nonrapid eye movement N‐REM sleep, as shown by their close association with the A phases of the cyclic alternating pattern. We examine the complex interactions between arousal mechanisms and rhythmic movements occurring during sleep. © 2004 Movement Disorder Society
Deficits in rapid adjustments of movements according to task constraints in Parkinson's disease
Authors: Tunik Eugene , Adamovich Sergei V. , Poizner Howard , Feldman Anatol G. 
Published: April 2004

AbstractThe role of the basal ganglia in the adaptive control of movement was investigated by unexpectedly perturbing movements in 8 patients with Parkinson's disease (PD) tested off medication and in 6 aged‐matched healthy subjects. Subjects performed two movement components simultaneously and without visual feedback: touching the nose with the finger while leaning the trunk forward. Subjects wore a harness connected to an electromagnet, which was attached to a wall. The trunk movement was mechanically blocked in randomly selected trials by engaging the electromagnet. While healthy subjects performed the task equally well in both conditions, PD subjects' hand movements significantly deteriorated in trunk‐perturbed compared to trunk‐free trials. Deteriorated hand movements were characterized by segmented hand paths, unsmooth velocity profiles, and prolonged movement times. This finding indicated that the relatively local trunk perturbation had a global effect on the hand movement of PD subjects, necessitating them to reinitiate, after some delay, their arm movement in perturbed trials. Thus, the basal ganglia may be a critical node in brain networks mediating the flexibility of responses to altered motor states. © 2004 Movement Disorder Society
Multiscale analysis of thermoregulation in the human microvascular system
Authors: Deuflhard Peter , Hochmuth Reinhard 
Published: April 2004

AbstractThe bio‐heat transfer equation is a macroscopic model for describing the heat transfer in microvascular tissue. So far the derivation of the Helmholtz term arising in the bio‐heat transfer equation is not completely satisfactory. Here we use homogenization techniques to show that this term may be understood as asymptotic result of boundary value problems which provide a microscopic description for microvascular tissue. An appropriate scaling of so‐called heat transfer coefficients in Robin boundary conditions on tissue–blood boundaries is seen to play the crucial role. In view of a future application of our new mathematical model for treatment planning in hyperthermia, we derive asymptotic estimates for the first‐order corrector. Copyright © 2004 John Wiley & Sons, Ltd.
Advances in loading techniques to design multifrequency monopole antennas
Authors: Soler J. , González F.J. , Puente C. , Anguera J. 
Published: April 2004

AbstractA top‐loading technique for monopole antennas which permits us to obtain a multiband performance from a wide set of antenna geometries is presented. Dual‐band and a triple‐band monopole antenna designs are described in detail, featuring both similar input impedances and radiation pattern across the different bands. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 41: 434–437, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20162
Visualization and tracking of an inflatable balloon catheter using SSFP in a flow phantom and in the heart and great vessels of patients
Authors: Miquel Marc E. , Hegde Sanjeet , Muthurangu Vivek , Corcoran Benjamin J. , Keevil Stephen F. , Hill Derek L.G. , Razavi Reza S. 
Published: April 2004

AbstractPassive catheter tracking involves direct interaction between the device and its surroundings, creating a local signal loss or enhancement of the image. Using only standard balloon catheters filled with CO2 and imaged with a steady‐state free precession sequence, it was possible to visualize and passively track catheters in a flow phantom and in the heart and great vessels of 20 patients without any additional image processing. The phantom work demonstrated that it was advantageous to sacrifice spatial resolution in order to increase temporal resolution. Frame rates greater than 10/sec were necessary for ease of catheter manipulation. Although only the tip of the catheter was visualized, this technique proved to be effective in patients undergoing cardiac catheterization. Magn Reson Med 51:988–995, 2004. © 2004 Wiley‐Liss, Inc.
Direct CSF injection of MnCl2 for dynamic manganese‐enhanced MRI
Authors: Liu Christina H. , D'Arceuil Helen E. , de Crespigny Alex J. 
Published: April 2004

AbstractMnCl2 was injected intrathecally through the cisterna magna in rats, allowing infusion of divalent manganese ions (Mn++) into the CSF space and thence into the brain, without breaking the blood–brain barrier (BBB). Mn++ uptake and washout dynamics in the brain were measured by serial T1‐weighted MRI and EPI T1 and T2 mapping for up to 3 weeks after injection. Observations within the first 6 hr after injection demonstrated anterograde and bilateral distribution of the Mn++ within the CSF space, from the olfactory bulb and frontal cortex to the brain stem. Enhancement increased in most brain areas up to 4 days after injection, and then slowly decreased. Relaxation maps at each time point demonstrated higher concentrations of Mn in basal ganglia. Residual concentrations were still observable after 3 weeks in all brain regions. With the use of MnCl2 calibration phantoms, the maximum Mn concentration in the brain was estimated to be approximately 27 ± 16 μM, corresponding to changes in relaxation rates of 0.49 ± 0.30 s−1 for R1 and 3.9 ± 2.4 s−1 for R2. For comparison, an intrathecal GdDTPA injection was performed. This injection showed different distribution dynamics: it remained chiefly within the CSF spaces, and was largely washed out after 1 day. This method shows promise as a means of supplying Mn++ uniformly to the whole brain for a variety of chronic functional activation studies. Magn Reson Med 51:978–987, 2004. © 2004 Wiley‐Liss, Inc.
Assessment of human pulmonary function using oxygen‐enhancedT1imaging in patients with cystic fibrosis
Authors: Jakob Peter M. , Wang Tungte , Schultz Georg , Hebestreit Helge , Hebestreit Alexandra , Hahn Dietbert 
Published: April 2004

AbstractIndirect qualitative MRI of pulmonary function is feasible using the paramagnetic effects of oxygen physically dissolved in blood. In this study, a more quantitative oxygen‐enhanced pulmonary function test based on the slope of a plot ofR1vs. oxygen concentration—the oxygen transfer function (OTF)—was developed and tested in a pool of five healthy volunteers and five patients with cystic fibrosis (CF). The lungT1relaxation rate,R1, under normoxic conditions (room air, 21% O2), and the response to various hyperoxic conditions (40%–100% O2) were studied. LungT1in healthy volunteers showed a relatively homogeneous distribution while they breathed room air, and a homogeneous decrease under hyperoxic conditions. LungT1in CF patients showed an inhomogeneous distribution while they breathed room air, and the observed lungT1decrease under hyperoxia depended on the actual state of the diseased lung tissue. In the selected group of CF patients, areas with reduced OTF also showed reduced perfusion, as confirmed by qualitative contrast‐enhanced MR pulmonary perfusion imaging. The results demonstrate that this completely noninvasive oxygen‐enhanced pulmonary function test has potential for clinical applications in the serial diagnosis of lung diseases such as CF. Magn Reson Med 51:1009–1016, 2004. © 2004 Wiley‐Liss, Inc.
Quantifying arbitrary magnetic susceptibility distributions with MR
Authors: Li Lin , Leigh John S. 
Published: April 2004

AbstractMagnetic susceptibility, as a physical property of materials, plays important roles in many physical, chemical, engineering, and medical applications. Its quantification becomes of significant interest when MRI becomes a commonly used technique in biomedical applications. A general method is presented here for quantifying arbitrary magnetic susceptibility distributions in a localized region on the basis of first principles of magnetic induction field distributions in space. A proof of the concept was demonstrated by computer simulations. The study establishes the methodological basis for quantitative magnetic susceptibility imaging with MR. Magn Reson Med 51:1077–1082, 2004. © 2004 Wiley‐Liss, Inc.
Human imaging of phosphorus in cortical and trabecular bone in vivo
Authors: Robson Matthew D. , Gatehouse Peter D. , Bydder Graeme M. , Neubauer Stefan 
Published: April 2004

AbstractPhosphorus was imaged in vivo in human cortical and trabecular bone and the T1 and T were measured. An ultrashort TE (UTE) pulse sequence (TE = 70 μm) was used with half pulse excitation and radial mapping of k‐space from the center out. T was measured using multiple echo times and T1 was measured both by saturation recovery and by a method using different RF pulse amplitudes. Seven normal subjects (32–85 years) were examined. Phosphorus was imaged, with a true in‐plane resolution of 2.9 × 2.9 mm and a signal‐to‐noise ratio (SNR) of 19:1, in both cortical and trabecular bone. The mean T value was 207 ± 12 μs, and the mean T1 value was 8.6 ± 3.0 sec. Images and measurements were obtained in realistic times on a clinical MR system. This may provide a new approach to characterizing disease of bone. Magn Reson Med 51:888–892, 2004. © 2004 Wiley‐Liss, Inc.
Selection of the optimum b factor for diffusion‐weighted magnetic resonance imaging assessment of ischemic stroke
Authors: Kingsley Peter B. , Monahan W. Gordon 
Published: April 2004

AbstractThe purpose of this study was to determine the diffusion sensitivity factor b that optimizes the contrast‐to‐noise ratio (CNR) for both diffusion‐weighted signal intensity and the apparent diffusion coefficient (ADCNR) when evaluating ischemic stroke by diffusion‐weighted MRI. The relative contrast, noise levels, CNR, and ADCNR were calculated for typical ADC values in human brain, 780 μm2/s in adults and 1200 μm2/s in neonates in normal tissue, 20–40% less in acute and subacute stroke, and 50% more in chronic stroke. The optimum b factor depends strongly on the ADC, whether TE is fixed or varies with the b factor, whether CNR or ADCNR is measured, and anisotropy. The optimum b factor in adults is 1000 s/mm2 in acute and chronic stroke, and 1200 s/mm2 in subacute stroke. The optimum values are about 200 s/mm2 lower in neonates than in adults. The CNR and ADCNR are within 10% of the optimum over at least a 2‐fold range of b factors, from 68–136% of the optimum b factor. If a single b factor is to be used for all situations, a diffusion b factor of 1000 s/mm2 is recommended. Magn Reson Med 51:996–1001, 2004. © 2004 Wiley‐Liss, Inc.
Magnetization tagging decay to measure long‐range 3He diffusion in healthy and emphysematous canine lungs
Authors: Woods Jason C. , Yablonskiy Dmitriy A. , Chino Kimiaki , Tanoli Tariq S.K. , Cooper Joel D. , Conradi Mark S. 
Published: April 2004

AbstractSpatial modulation (tagging) of the longitudinal magnetization allows diffusive displacements to be measured over times approximately as long as T1 and over correspondingly long distances. Magnetization tagging is used here with hyperpolarized 3He gas in canine lungs with unilateral elastase‐induced emphysema. A new scheme for analyzing images subsequent to tagging determines the spatially‐resolved fractional modulation and its decay rate, using a sliding window. The diffusivity so determined over seconds and centimeter lengths, Dsec, is smaller in all cases than the diffusivity measured over milliseconds and hundreds of microns, Dmsec (in healthy lungs, this ratio is about 0.1). While Dmsec is sensitive to lung microstructure on the alveolar level, Dsec reflects airway connectivity and provides new information on lung structure. The results show substantial increases in Dsec in the lungs of four dogs with clear evidence of emphysema. For these dogs, the fractional increase in long‐range diffusivity Dsec in the emphysematous lungs was greater than that in short‐range diffusivity Dmsec. Magn Reson Med 51:1002–1008, 2004. © 2004 Wiley‐Liss, Inc.
Improved route for the visualization of stem cells labeled with a Gd‐/Eu‐Chelate as dual (MRI and fluorescence) agent
Authors: Crich Simonetta Geninatti , Biancone Luigi , Cantaluppi Vincenzo , Duò Debora , Esposito G. , Russo Simona , Camussi Giovanni , Aime Silvio 
Published: April 2004

AbstractA simple labeling procedure of stem/progenitor cells based on the use of Gd‐HPDO3A and Eu‐HPDO3A, respectively, is described. The Gd‐chelate acts as T1‐agent for MRI visualization, whereas the corresponding Eu‐chelate acts as reporter in fluorescence microscopy. Owing to their substantial chemical equivalence, the two chelates are equally internalized in EPCs (endothelial progenitor cells), thus allowing their visualization by both techniques. The lanthanide chelates are entrapped in endosomic vesicles and the labeled cells retain biological activity with preservation of viability and pro‐angiogenesis capacity. Hyperintense spots in MR have been observed for Gd‐labeled EPCs injected under mice kidney capsule or grafted on a subcutaneous Matrigel plug up to 14 days after transplantation. Magn Reson Med 51:938–944, 2004. © 2004 Wiley‐Liss, Inc.
Quantitative t1ρ NMR spectroscopy of rat cerebral metabolites in vivo: Effects of global ischemia
Authors: Kettunen Mikko I. , Gröhn Olli H.J. , Kauppinen Risto A. 
Published: April 2004

AbstractThe NMR relaxation times (T1ρ, T2, and T1) of water, N‐acetylaspartate (NAA), creatine (Cr), choline‐containing compounds (Cho), and lactate (Lac) were quantified in rat brain at 4.7 T. In control animals, the cerebral T1ρ figures, as determined with a spin‐lock field of 1.0 G, were 575 ± 30 ms, 380 ± 19 ms, 705 ± 53 ms, and 90 ± 1 ms for NAA, Cr, Cho, and water, respectively. The T1ρ figures were 62–103% longer than their respective T2 values determined by a multiecho method. In global (ischemic) ischemia, T1ρ of NAA declined by 34%, that of Cr and Cho did not change, and that of water increased by 10%. The T1ρ of lactate in ischemic brain was 367 ± 44 ms. Similar patterns of changes were observed in the multiecho T2 of these cerebral metabolites. The T1 of water and NAA changed in a fashion similar to that of T1ρ and T2. These results show differential responses in metabolite and water T1ρ relaxation times following ischemia, and indicate that metabolite T1ρ and T2 relaxation times behave similarly in the ischemic brain. The contributions of dipolar and nondipolar effects on T1ρ relaxation in vivo are discussed in this work. Magn Reson Med 51:875–880, 2004. © 2004 Wiley‐Liss, Inc.
Is muscle spindle proprioceptive function spared in muscular dystrophies? A muscle tendon vibration study
Authors: Ribot‐Ciscar Edith , Tréfouret Sylvie , Aimonetti Jean‐Marc , Attarian Shahram , Pouget Jean , Roll Jean‐Pierre 
Published: April 2004

AbstractMuscular dystrophies (MDs) are characterized by the degeneration of skeletal muscle fibers. The aim of the present study was to determine whether the intrafusal fibers of muscle spindles are also affected in MD. The functional integrity of muscle spindles was tested by analyzing their involvement in the perception of body segment movements and in the control of posture. Twenty MD patients (4 with dystrophinopathy, 5 with myotonic dystrophies, 5 with fascioscapulohumeral MD, and 6 with limb‐girdle dystrophies) and 10 healthy subjects participated in the study. The MD patients perceived passive movements and experienced illusory movements similar to those perceived by healthy subjects in terms of their direction and velocity. Vibratory stimulation applied to the neck and ankle muscle tendons induced postural responses in MD patients with spatial and temporal characteristics similar to those produced by healthy subjects. These results suggest that the proprioceptive function of muscle spindles is spared in muscular dystrophies. Muscle Nerve 29: 861–866, 2004
Reliability of quantitative motor unit action potential parameters
Authors: Takehara Itaru , Chu Jennifer , Li Tung‐Chou , Schwartz Ira 
Published: April 2004

AbstractWe evaluated the test–retest reliability (reproducibility) of motor unit action potential (MUAP) parameters in multi‐MUAP analysis over time. Reproducibility studies are not available for needle quantitative electromyography (QEMG) performed by the same examiner. Fourteen consecutive individuals (10 men and 4 women) had repeat QEMG at 3 hours after the first examination, and seven (5 men and 2 women) had a repeat QEMG after 4–10 days. The intraclass correlation coefficient (ICC) was 87–97% with same‐day testing and 52–81% with different‐day testing. Size index and firing rate were the most reproducible, suggesting use in follow‐up multi‐MUAP studies. Muscle Nerve 30: 111–113, 2004
Painful peripheral neuropathy and its nonsurgical treatment
Authors: Wolfe Gil I. , Trivedi Jaya R. 
Published: April 2004

AbstractTreatment of neuropathic pain is the primary focus of management for many patients with painful peripheral neuropathy. Antidepressants and anticonvulsants are the two pharmacological classes most widely studied and represent first‐line agents in the management of neuropathic pain. The number of pharmacological agents that have demonstrated effectiveness for neuropathic pain continues to expand. In the current review, we summarize data from randomized, controlled pharmacological trials in painful peripheral neuropathies. Although neuropathic pain management remains challenging because the response to therapy varies considerably between patients, and pain relief is rarely complete, a majority of patients can benefit from monotherapy using a well‐chosen agent or polypharmacy that combines medications with different mechanisms of action. Muscle Nerve 30: 3–19, 2004
Whiplash: Pathophysiology, diagnosis, treatment, and prognosis
Authors: Rodriquez Arthur A. , Barr Karen P. , Burns Stephen P. 
Published: April 2004

AbstractWe have reviewed the literature relevant to pathophysiology, diagnosis, treatment, and prognosis of whiplash‐associated disorder (WAD) since 1995 and provided a brief summary of literature pertaining to forces action on the head and neck during a motor vehicle accident. The scope of the current review is confined to the Quebec guidelines for WAD grades 1–3 but excludes grade 4 (neck complaints and fracture or dislocation). After excluding papers without scientific data and single case reports or case series with fewer than 20 patients, articles were reviewed for methodological quality. The diagnosis remains clinical. No imaging, physiological, or psychological study provides specific diagnostic criteria. In the acute period up to 2 weeks, soft collars or rest and work‐leave do not shorten the duration of neck pain. Sick leave is reduced by high‐dose methylprednisolone given within 8 h of injury, but confirmatory studies examining the cost–benefit relationship are needed. In the first 6 months, active as opposed to passive treatment results in improved outcomes. Specific exercise strategies have not been studied. For those with symptoms lasting more than 6 months, percutaneous radio‐frequency neurotomy can provide pain relief for many months in those responding to blind local anesthetic facet blocks. Intra‐articular corticosteroids are ineffective. Uncontrolled trials suggest that multimodal rehabilitation programs result in improved overall function. The overall prognosis for recovery has varied considerably across studies. Such variability is likely due to differences in case identification methods and whether outcome is assessed in terms of symptoms or the receipt of financial compensation for injury. The impact on prognosis of both collision‐ and patient‐related factors is also reviewed. Muscle Nerve 29: 768–781, 2004
Cavitation of rubber particles in high‐impact polystyrene: Effects of crosslinking by γ‐irradiation
Authors: Bucknall C.B. , Soares V.L.P. 
Published: April 2004

AbstractTensile tests on high‐impact polystyrene (HIPS) show that a 60 Mrad dose of γ‐radiation raises the yield stress from 11.5 to 19.8 MPa, and the flow stress from 10.0 to 19.6 MPa, while reducing the elongation at break from 50 to 4%. Similar reductions in fracture resistance are observed in irradiated Charpy impact specimens. The Tg of the rubber phase shifts from −70 to −57 °C, and its estimated shear modulus increases from 0.1 to 0.5 MPa. It is concluded that the observed changes in mechanical properties are due almost entirely to crosslinking of the polybutadiene. This not only inhibits cavitation and fibrillation in the rubbery membranes of the “salami” particles, thereby delaying yield, but also makes the fibrillated membranes more resistant to further dilatation, so that rates of craze thickening in the polystyrene matrix are reduced. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 2168–2180, 2004