bluuebunny/crossref_metadata_2025_split huggingface dataset:
Fast proton spectroscopic imaging with high signal‐to‐noise ratio: Spectroscopic RARE
Authors: Dreher Wolfgang , Leibfritz Dieter 
Published: August 2002

AbstractA new fast spectroscopic imaging (SI) method is presented which is based on spatial localization by the fast MRI method of rapid acquisition with relaxation enhancement (RARE) and encoding of the chemical shift information by shifting the position of a refocusing 180° pulse in a series of measurements. This method is termed spectroscopic RARE. In contrast to spectroscopic ultrafast low‐angle RARE (U‐FLARE), the formation of two echo families (odd and even) is suppressed by using a train of 180° RF pulses with an internal four‐step phase cycle. By this means a high signal‐to‐noise ratio (SNR) per unit measurement time is obtained, because the separation of odd and even echoes, as well as dummy echoes to stabilize the echo amplitudes, is not needed anymore. The method is of particular interest for detecting signals of coupled spins, as effective homonuclear decoupling can be achieved by use of constant evolution time chemical shift encoding. The pulse sequence was implemented on a 4.7 T imaging system, tested on phantoms, and applied to the healthy rat brain in vivo. Spectroscopic RARE is particularly useful if T ≪ T2, which is typically fulfilled for in vivo proton SI measurements at high magnetic field strength. Magn Reson Med 47:523–528, 2002. © 2002 Wiley‐Liss, Inc.
Signal‐to‐noise ratio and absorbed power as functions of main magnetic field strength, and definition of “90°” RF pulse for the head in the birdcage coil
Authors: Collins Christopher M. , Smith Michael B. 
Published: August 2002

AbstractCalculations of the RF magnetic (B1) field as a function of frequency between 64 and 345 MHz were performed for a head model in an idealized birdcage coil. Absorbed power (Pabs) and SNR were calculated at each frequency with three different methods of defining excitation pulse amplitude: maintaining 90° flip angle at the coil center (center α = π/2), maximizing FID amplitude (Max. AFID), and maximizing total signal amplitude in a reconstructed image (Max. Aimage). For center α = π/2 and Max. Aimage, SNR increases linearly with increasing field strength until 260 MHz, where it begins to increase at a greater rate. For these two methods, Pabs increases continually, but at a lower rate at higher field strengths. Above 215 MHz in MRI of the human head, the use of FID amplitude to set B1 excitation pulses may result in apparent decreases in SNR and power requirements with increasing static field strength. Magn Reson Med 45:684–691, 2001. © 2001 Wiley‐Liss, Inc.
Characterization and reduction of the transient response in steady‐state MR imaging
Authors: Hargreaves Brian A. , Vasanawala Shreyas S. , Pauly John M. , Nishimura Dwight G. 
Published: August 2002

AbstractRefocused steady‐state free precession (SSFP) imaging sequences have recently regained popularity as faster gradient hardware has allowed shorter repetition times, thereby reducing SSFP's sensitivity to off‐resonance effects. Although these sequences offer fast scanning with good signal‐to‐noise efficiency, the “transient response,” or time taken to reach a steady‐state, can be long compared with the total imaging time, particularly when using 2D sequences. This results in lost imaging time and has made SSFP difficult to use for real‐time and cardiac‐gated applications. A linear‐systems analysis of the steady‐state and transient response for general periodic sequences is shown. The analysis is applied to refocused‐SSFP sequences to generate a two‐stage method of “catalyzing,” or speeding up the progression to steady‐state by first scaling, then directing the magnetization. This catalyzing method is compared with previous methods in simulations and experimentally. Although the second stage of the method exhibits some sensitivity to B1 variations, our results show that the transient time can be significantly reduced, allowing imaging in a shorter total scan time. Magn Reson Med 46:149–158, 2001. © 2001 Wiley‐Liss, Inc.
Volumetric multishot echo‐planar spectroscopic imaging
Authors: Tyszka J. Michael , Mamelak Adam N. 
Published: August 2002

AbstractRapid volumetric magnetic resonance spectroscopic imaging (MRSI) is potentially of great relevance to the diagnosis and treatment of focal cerebral diseases such as cancer and epilepsy. A strategy for volumetric multishot echo‐planar spectroscopic imaging (MEPSI) is described which allows whole‐brain metabolite mapping in approximately 20 min. A multishot trajectory is used in both the spatial and temporal domains which reduces the accumulated phase during each echo train and tolerates conventional Fourier reconstruction without regridding. Also described is a generalized correction for phase discontinuities arising from the multishot acquisition of the time domain, which is independent of the spatial k‐space trajectory and is therefore also applicable to multishot spiral MRSI. Whole‐brain, lipid‐suppressed MEPSI data were acquired from five normal subjects. The mean signal‐to‐noise ratios (SNRs) (±SE) for the n‐acetylaspartate (NAA), choline (Cho), and creatine (Cr) maps across all subjects were 21.3 ± 1.8, 11.7 ± 0.6, and 9.2 ± 0.6, respectively, with a computed voxel size of 2.33 ml. Magn Reson Med 46:219–227, 2001. © 2001 Wiley‐Liss, Inc.
Transient forearm conduction block in the median nerve
Authors: Watson Bradley V. , Parkes Anthony W. , Brown John D. 
Published: August 2002

AbstractWe present two cases referred for electrophysiological confirmation of carpal tunnel syndrome (CTS). Initial nerve conduction studies were normal. Approximately 20 min into the examination, both patients developed sensory symptoms and weakness in the distal median nerve territory while the elbow was extended and forearm supinated. Further studies demonstrated complete conduction block across the forearm in the median motor and sensory nerve fibers. When measurable, conduction velocities remained normal or were modestly slow. Complete clinical and electrophysiological recovery occurred within 2 min following forearm pronation, suggesting that dysfunction was probably due to focal transient ischemia. Patients describing increased sensory symptoms during routine electrophysiological assessments for CTS should be investigated to rule out the possibility of a more proximal abnormality. © 2002 Wiley Periodicals, Inc. Muscle Nerve 25: 000–000, 2002
A small dose of the immunosuppressive agent FK506 (tacrolimus) protects peripheral nerve from ischemic fiber degeneration
Authors: Kihara Mikihiro , Kamijo Mikiko , Nakasaka Yoshikuni , Mitsui Yoshiyuki , Takahashi Mitsuo , Schmelzer James D. 
Published: August 2002

AbstractThe immunosuppressant agent FK506 (tacrolimus) has proven to be neuroprotective against brain ischemia, but there are no data on potential neuroprotective effects of FK506 in peripheral nerve ischemia. We examined the potential effects of two doses of FK506 in protecting peripheral nerve from ischemic fiber degeneration. Ischemia in the left sciatic nerve of the rat was produced by injecting 2 × 106 microspheres (14 μm) into the left femoral, hypogastric, and superior gluteal arteries in proportions of 47%, 37%, and 17%, respectively. After embolization, FK506 was injected into the left femoral, hypogastric, and superior gluteal arteries in doses of 9.4, 7.4, and 3.4 μg, respectively, for the high‐dose group and 4.7, 3.7, and 1.7 μg, respectively, for the low‐dose group. The control rats were injected with saline. FK506 treatment resulted in dramatic behavioral improvement in nerve function, in the number of functioning nerve fibers, and in the salvage of a majority of nerve fibers from ischemic fiber degeneration in a dose‐dependent fashion. These results suggest that a small dose of FK506 protects peripheral nerve from ischemic fiber degeneration and that it may have potential in the treatment of ischemic neuropathy. © 2001 John Wiley & Sons, Inc. Muscle Nerve 24: 1601–1606, 2001
Wave‐induced seepage flux into anisotropic seabeds
Authors: Jeng D. S. , Li L. , Barry D. A. 
Published: August 2002

AbstractConsiderable effort has been devoted to quantifying the wave‐induced soil response in a porous seabed in the last few decades. Most previous investigations have focused on the analysis of pore pressure and effective stresses within isotropic sediments, despite strong evidence of anisotropic soil behaviour reported in the literature. Furthermore, the seepage flux, which is important in the context of contaminant transport, has not been examined. In this paper, we focus on water wave‐driven seepage in anisotropic marine sediments of finite thickness. The numerical results predict that the effects of hydraulic anisotropy and anisotropic soil behaviour on the wave‐driven seepage in marine sediment are significant. Copyright © 2001 John Wiley & Sons, Ltd.
Data from frequency‐volume charts versus filling cystometric estimated capacities and prevalence of instability in men with lower urinary tract symptoms suggestive of benign prostatic hyperplasia
Authors: van Venrooij Ger E.P.M. , Eckhardt Mardy D. , Gisolf Karel W.H. , Boon Tom A. 
Published: August 2002

AbstractThe aim was to examine associations of filling cystometric estimated compliance, capacities, and prevalence of bladder instability with data from frequency‐volume charts in a well‐defined group of men with lower urinary tract symptoms (LUTS) suggestive of benign prostatic hyperplasia (BPH). Men with LUTS suggestive of BPH were included if they met the criteria of the International Consensus Committee on BPH, i.e., they voided more than 150 mL during uroflowmetry, their residual volume and prostate size were estimated, and they completed frequency‐volume charts correctly. From the frequency‐volume charts, voiding habits, and fluid intake in the daytime and at night were evaluated. Filling cystometric studies were performed in these men as well. Decreased compliance was an exceptional finding. Cystometric capacity and especially effective capacity (cystometric capacity minus residual volume) corresponded significantly with the maximum voided volume on the frequency‐volume charts. Effective capacity was almost twice as high as the average voided volume. Minimum voided volume on frequency‐volume charts was not related to filling cystometric data. The presence of instability in the supine or sitting position or in both positions was not significantly associated with smaller voided volumes, higher nocturia, or diuria. Filling cystometric capacities were strongly associated with maximal and mean voided volumes derived from frequency‐volume charts. The presence of detrusor instability during filling cystometry did not significantly affect voided volumes, diuria, or nocturia. Neurourol. Urodynam. 21:106–111, 2002. © 2002 Wiley‐Liss, Inc.
Low‐cost minimum‐time line‐broadcasting schemes in complete binary trees
Authors: Averbuch A. , Gaber I. , Roditty Y. 
Published: August 2002

AbstractBroadcasting is the process of transmitting a message from a member in a network (originator) to all other members. A line‐broadcasting scheme allows two members to communicate during one time unit as long as there is a path of lines between them and no link is used in more than one call between two members. Farley [3] showed an algorithm that accomplishes line broadcasting in any tree on n vertices in minimum time, which is ⌈log2 n⌉ time units. Since the structure of the tree is unknown in advance, the total number of communication link uses (cost) of his scheme is Θ (n − 1) ⌈log2 n⌉.In this paper, we present line‐broadcasting schemes for complete binary trees. The cost of the algorithms is linear in the number of vertices. This answers a question raised by Fujita and Farley [5]. © 2001 John Wiley & Sons, Inc.
An implicit boundary element solution with consistent linearization for free surface flows and non‐linear fluid–structure interaction of floating bodies
Authors: Donescu Pompiliu , Virgin Lawrence N. 
Published: August 2002

AbstractIn this work, a new comprehensive method has been developed which enables the solution of large, non‐linear motions of rigid bodies in a fluid with a free surface. The application of the modern Eulerian–Lagrangian approach has been translated into an implicit time‐integration formulation, a development which enables the use of larger time steps (where accuracy requirements allow it). Novel features of this project include: (1) an implicit formulation of the rigid‐body motion in a fluid with a free surface valid for both two or three dimensions and several moving bodies; (2) a complete formulation and solution of the initial conditions; (3) a fully consistent (exact) linearization for free surface flows valid for any boundary elements such that optimal convergence properties are obtained when using a Newton–Raphson solver. The proposed framework has been completed with details on implementation issues referring mainly to the computation of the complete initial conditions and the consistent linearization of the formulation for free surface flows.The second part of the paper demonstrates the mathematical and numerical formulation through numerical results simulating large free surface flows and non‐linear fluid structure interaction. The implicit formulation using a fully consistent linearization based on the boundary element method and the generalized trapezoidal rule has been applied to the solution of free surface flows for the evolution of a triangular wave, the generation of tsunamis and the propagation of a wave up to overturning. Fluid–structure interaction examples include the free and forced motion of a circular cylinder and the sway, heave and roll motion of a U‐shaped body in a tank with a flap wave generator. The presented examples demonstrate the applicability and performance of the implicit scheme with consistent linearization. Copyright © 2001 John Wiley & Sons. Ltd.
An improved partition of unity finite element model for diffraction problems
Authors: Ortiz P. , Sanchez E. 
Published: August 2002

AbstractThe partition of unity finite element method (PUFEM) is explored and improved to deal with practical diffraction problems efficiently. The use of plane waves as an external function space allows an efficient implementation of an approximate exterior non‐reflective boundary condition, improving the original proposed by Higdon for general diffraction problems. A ‘virtually’ analytical integration procedure is introduced for multi‐dimensional high‐frequency problems which exhibits a dramatic decrease in the number of operations for a given error compared with standard integration methods. Suitable conjugate gradient type solvers for the whole range of wavenumbers are used, including such cases in which PUFEM can produce nearly singular matrices caused by ‘round‐off’ limits. Copyright © 2001 John Wiley & Sons, Ltd.
The p‐version of the finite element method for three‐dimensional curved thin walled structures
Authors: Düster A. , Bröker H. , Rank E. 
Published: August 2002

AbstractIn this paper we present an implementation of a three‐dimensional p‐version for structural problems of solids with almost arbitrarily curved surfaces. Applying the blending function method, complex structures can often be modelled by a few p‐elements, being the basis for a higher order approximation. Numerical examples will demonstrate, that the p‐version with anisotropic Ansatz spaces allows to predict the structural behaviour of three‐dimensional plates and shells with approximately the same amount of degrees of freedom as in the two‐dimensional case, yet significantly more accurate due to the three‐dimensional model. Furthermore, it is advantageous to compute complex structures exclusively with three‐dimensional discretizations as no special elements are needed to model the transition from dimensionally reduced formulations like plates or shells to fully three‐dimensional solid elements. Using the p‐version with anisotropic Ansatz spaces the whole structure can be efficiently discretized with solid elements, even if the aspect ratio of the elements becomes very large. Copyright © 2001 John Wiley Sons, Ltd.
General theory of domain decomposition: Indirect methods
Authors: Herrera Ismael , Yates Robert , Diaz Martin 
Published: August 2002

AbstractAccording to a general theory of domain decomposition methods (DDM), recently proposed by Herrera, DDM may be classified into two broad categories: direct and indirect (or Trefftz‐Herrera methods). This article is devoted to formulate systematically indirect methods and apply them to differential equations in several dimensions. They have interest since they subsume some of the best‐known formulations of domain decomposition methods, such as those based on the application of Steklov‐Poincaré operators. Trefftz‐Herrera approach is based on a special kind of Green's formulas applicable to discontinuous functions, and one of their essential features is the use of weighting functions which yield information, about the sought solution, at the internal boundary of the domain decomposition exclusively. A special class of Sobolev spaces is introduced in which boundary value problems with prescribed jumps at the internal boundary are formulated. Green's formulas applicable in such Sobolev spaces, which contain discontinuous functions, are established and from them the general framework for indirect methods is derived. Guidelines for the construction of the special kind of test functions are then supplied and, as an illustration, the method is applied to elliptic problems in several dimensions. A nonstandard method of collocation is derived in this manner, which possesses significant advantages over more standard procedures. © 2002 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq 18: 296–322, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/num.10008
Effects of biologic and experiential conditions on the pattern of growth in weight of premature and full‐term infants
Authors: Pridham Karen F. , Brown Roger , Sondel Sherie , Clark Roseanne , Green Christopher 
Published: August 2002

AbstractIn this exploratory study we examined the contribution of biologic and experiential conditions to the pattern of growth in weight for premature and full‐term infants. The three components of the pattern were: (a) the infant's weight level; (b) the linear growth rate; and (c) the quadratic growth rate. Biologic conditions were maturity at birth and gender. Experiential conditions included variables in the mother's caregiving and the infant's feeding behavior, nutrient intake, and acuity of illness. At 1, 4, 8, and 12 months, premature infants (n = 61) weighed significantly less than full‐term infants (n = 53), but neither linear nor quadratic rates of weight gain were significantly different from the rates for the full‐term infants. Multilevel analytic models showed that female gender significantly affected weight level and linear and quadratic growth rates. Negative affect and behavior in both the mother and the infant significantly increased the linear rate of weight gain. The interaction of several experiential conditions with the two biologic conditions, birth maturity and gender, affected growth outcomes. Further exploration of the model with a larger sample is indicated to enable simultaneous testing of biologic and experiential conditions. © 2001 John Wiley & Sons, Inc. Res Nurs Health 24:283–297, 2001
Reconsideration of criteria for differentiating faunal assemblages accumulated by hyenas and hominids
Authors: Pickering Travis Rayne 
Published: August 2002

AbstractZooarchaeologists have established several criteria for differentiating hominid‐ and hyena‐derived faunal assemblages. In some cases, however, the patterns of skeletal part representation and bone surface modification on which these criteria are ultimately based have been observed in fossil bone assemblages of unknown origin, rather than in modern assemblages of known origin. When the proposed criteria are evaluated within an actualistic framework, only three are able to differentiate between hominid‐ and hyena‐created faunal assemblages. I suggest that only these three criteria—proportions of carnivores to ungulates in the assemblage, the preserved condition of long bone specimens (either as whole cylinders or as splintered shaft fragments), and the types of bone surface modifications—should be retained as important factors in a diagnosis of the ancient bone‐collector. The remaining four criteria—the relative proportion of horn pieces in the assemblage, the relative representation of podial bones, the relative representation of small and large bovid skeletal parts, and bovid mortality profiles—are not relevant or applicable to the problem of differentiating hominid‐ from hyena‐derived faunal assemblages. Copyright © 2002 John Wiley & Sons, Ltd.
Development of an efficient system for the separation of indole alkaloids by high performance liquid chromatography and its applications
Authors: Gerasimenko Irina , Sheludko Yuri , Unger Matthias , Stöckigt Joachim 
Published: August 2002

AbstractAn efficient system for the analysis of indole alkaloids by HPLC on a reversed‐phase column using an ion pair technique is described. The optimised chromatographic conditions allowed the successful separation of 22 standard monoterpenoid indole alkaloids (including some isomers) and tryptamine. The described HPLC system was applied to the analysis of alkaloids in intergeneric somatic hybrid cell cultures of Rauvolfia serpentina × Rhazya stricta. Copyright © 2001 John Wiley & Sons, Ltd.
Identification of the alkaloids of Galipea officinalis by gas chromatography–mass spectrometry
Authors: Jacquemond‐Collet Ingrid , Bessière Jean‐Marie , Hannedouche Sébastien , Bertrand Cédric , Fourasté Isabelle , Moulis Claude 
Published: August 2002

AbstractGalipea officinalis Hancock, a Venezuelan shrubby tree which is acclaimed in folk medicine for its many healing properties, is the only species of the genus to contain tetrahydroquinoline alkaloids. A GC‐MS method has been developed in order to analyse the essential oil, hexane and chloroform extracts of the trunk bark of this plant, without prior derivatisation of the alkaloidal components. A study of the MS fragmentation patterns of the components permitted the identification of five new minor quinoline alkaloids together with the known alkaloids. In addition, the method could also be used for the characterisation of alkaloids within the genus Galipea. Copyright © 2001 John Wiley & Sons, Ltd.
Non‐mosaic trisomy 20 presenting at 21 weeks' gestation as a thoraco‐abdominal mass
Authors: Driggers Rita W. , Bernstein Helene , Lantz Michael , Stetten Gail , Escallon Cathleen S. , Perlman Elizabeth , Blakemore Karin J. 
Published: August 2002

AbstractNon‐mosaic trisomy 20 is rare in fetuses surviving beyond the first trimester. We report a case of a fetus with non‐mosaic trisomy 20 in amniotic fluid cultures obtained during the prenatal evaluation of an unusual thoraco‐abdominal mass which was found at autopsy to be pulmonary sequestration. Gross inspection and autopsy of the fetus revealed multiple anomalies. Copyright © 2001 John Wiley & Sons, Ltd.