bluuebunny/crossref_metadata_2025_split huggingface dataset:
CAD of coaxially end‐fed waveguide phased‐array antennas
Authors: Galdi Vincenzo , Gerini Giampiero , Guglielmi Marco , Visser Huib J. , D'Agostino Francesco 
Published: October 2002

AbstractAn alternative configuration for an infinite coaxially end‐fed waveguide phased‐array antenna is explored. In the proposed configuration, the integration of the end‐fed launcher and the output waveguide, rather than the waveguide in itself, acts as a basic radiator. This allows the design of more compact antenna elements. In order to analyze and optimize the structure, an accurate full‐wave simulation tool based on the multimode admittance matrix representation is developed. Results are validated against state‐of‐the‐art commercial CAD software. Numerical simulations involving singly and doubly tuned configurations are presented and discussed to illustrate the potential convenience of the proposed configuration and of the CAD tool developed. © 2002 Wiley Periodicals, Inc. Microwave Opt Technol Lett 34: 276–281, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10437
A compact dual‐port, dual‐band planar microstrip antenna
Authors: Gadzina A. , Słobodzian P. 
Published: October 2002

AbstractA compact dual‐band, dual‐port planar microstrip antenna is described. Its main properties are wide bandwidth, high and constant gain at both frequency bands, and a simple planar structure, which results from etching all patches onto a common substrate. As an example of application an antenna for GSM900/1800 has been realized and described with measured data. © 2002 Wiley Periodicals, Inc. Microwave Opt Technol Lett 34: 302–305, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10443
Parallel FDTD analysis of active integrated antenna array
Authors: Chu Qing‐Xin , Chan Ka‐Fai , Chan Chi‐Hou 
Published: October 2002

AbstractThe active integrated antenna array given in [4] is simulated by use of a parallel FDTD algorithm to reduce the computational requirement. A four‐unit array with dual modes and dual frequencies is presented in this paper. © 2002 Wiley Periodicals, Inc. Microwave Opt Technol Lett 34: 317–319, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10447
Treatment of childhood acute lymphoblastic leukemia at a regional non‐academic center in Belarus
Authors: Chunikhovskiy Sergey P. , Zelterman Daniel , van Hoff Jack 
Published: October 2002

AbstractThe outlook for children with cancer is improving in the less privileged nations of the world. This report from Belarus is representative of results that can be achieved. Med Pediatr Oncol 2002;39:202–206. © 2002 Wiley‐Liss, Inc.
The first automated 470.59 MHz 19F NMR‐controlled titration: dissociation constants and ion‐specific chemical shifts of 2‐amino‐4‐fluoro 2‐methylpent‐4‐enoic acid
Authors: Uhlemann C. E. , Pfaff C. G. , Hägele G. , Laue K. W. , Lübke M. , Haufe G. 
Published: October 2002

Abstract2‐Amino‐4‐fluoro‐2‐methylpent‐4‐enoic acid, obtained as a 1 : 1 salt with trifluoro‐acetic acid, was characterized by 1H and 19F high‐resolution NMR spectroscopy. High‐precision potentiometry led to the dissociation constants pK = 1.879 and pK = 9.054. The first automated 470.59 MHz 19F NMR‐controlled titration yielded the dynamic chemical shift 〈δF〉 as a function of pcH or τ and the ion‐specific chemical shifts: δF(H2L+) = −94.81 ppm, δF(HL) = −94.21 ppm, δF(L−) = −92.45 ppm. The deprotonation gradients were found to be Δ1 = −0.60 ppm and Δ2 = −1.76 ppm. Copyright © 2002 John Wiley & Sons, Ltd.
Conformational analysis of some 1R,4S‐2‐arylidene‐p‐menthan‐3‐ones by 1H NMR spectroscopy and molecular simulation
Authors: Pivnenko Nikolay S. , Drushlyak Tatyana G. , Kutulya Lidiya A. , Vashchenko Valeriy V. , Doroshenko Andrey O. , Goodby John W. 
Published: October 2002

AbstractBased on 1H NMR spectral analysis combined with molecular simulation, conformational states of the cyclohexanone ring were studied for some 1R,4S‐2‐(4‐X‐benzylidene)‐p‐menthan‐3‐ones (X = COOCH3 or C6H5) in CDCl3 and C6D6. The co‐existence of chair conformers with an axial orientation of both alkyl substituents and twist‐boat forms was established for the compounds studied at room temperature (22–23° C). The substituent X does not influence appreciably the ratio of these conformers, but the fraction of twist‐boat forms increases noticeably in benzene solutions as compared with CDCl3 solutions. Rotameric states of the isopropyl fragment were also characterised for the compounds studied. Distinctions in conformational states for the 1R,4S‐2‐arylidene‐p‐menthan‐3‐ones and (−)‐menthone were revealed and are discussed. Copyright © 2002 John Wiley & Sons, Ltd.
Genetic basis of rett syndrome
Authors: Van den Veyver Ignatia B. , Zoghbi Huda Y. 
Published: October 2002

AbstractThe origin of Rett syndrome has long been debated, but several observations have suggested an X‐linked dominant inheritance pattern. We and others have pursued an exclusion‐mapping strategy using DNA from a small number of familial Rett syndrome cases. This work resulted in the narrowing of the region likely to harbor the mutated gene to Xq27.3‐Xqter. After systematic exclusion of several candidate genes, we discovered mutations in MECP2, the gene that encodes the transcriptional repressor, methyl‐CpG‐binding protein 2. Since then, nonsense, missense, or frameshift mutations have been found in at least 80% of girls affected with classic Rett syndrome. Sixty‐four percent of mutations are recurrent C > T transitions at eight CpG dinucleotides mutation hotspots, while the C‐terminal region of the gene is prone to recurrent multinucleotide deletions (11%). Most mutations are predicted to result in total or partial loss of function of MeCP2. There is no clear correlation between the type and position of the mutation and the phenotypic features of classic and variant Rett syndrome patients, and XCI appears to be a major determinant of phenotypic severity. Further research focuses on the pathogenic consequences of these mutations along the hypothesis of loss of transcriptional repression of a small number of genes that are essential for neuronal function in the maturing brain. MRDD Research Reviews 2002;8:82–86. © 2002 Wiley‐Liss, Inc.
Design of a SENSE‐optimized high‐sensitivity MRI receive coil for brain imaging
Authors: de Zwart Jacco A. , Ledden Patrick J. , Kellman Peter , van Gelderen Peter , Duyn Jeff H. 
Published: October 2002

AbstractAn 8‐channel receive‐only detector array was developed for SENSE MRI of human brain. The coil geometry was based on a gapped element design and used ultra‐high impedance preamplifiers for mutual decoupling of the elements. Computer simulations of the electric and magnetic fields showed that excellent signal‐to‐noise ratio (SNR) and SENSE performance could be achieved by placing the coil elements close to the head and maintaining a substantial gap between the elements. Measurements with a 1.5 T prototype coil showed a 2.7‐fold improvement of the SNR averaged over the brain compared to a conventional quadrature birdcage receive coil and an average geometrical noise amplification factor (g‐value) of 1.06 and 1.38 for rate‐2 and rate‐3 SENSE, respectively. Magn Reson Med 47:1218–1227, 2002. Published 2002 Wiley‐Liss, Inc.
On the timing characteristics of the apparent diffusion coefficient contrast in fMRI
Authors: Gangstead Stacey L. , Song Allen W. 
Published: October 2002

AbstractFor the past 10 years, functional MRI (fMRI) has seen rapid progress in both clinical and basic science research. Most of the imaging techniques are based on the blood oxygenation level‐dependent (BOLD) contrast which arises from the field perturbation of the paramagnetic deoxyhemoglobin due to the mismatch between the local oxygen demand and delivery. Because the changes of oxygenation level take place mostly in the veins, the dominant signal sources of the BOLD signal are intra‐ and extravascular proton pools of the veins. Perfusion imaging methods, developed parallel to the BOLD technique, seek to quantify the blood flow and perfusion. Recently, perfusion imaging using arterial spin tagging methods have been used to study brain function by investigating the changes of the blood flow and perfusion during brain activation, thereby generating an alternative contrast mechanism to the functional brain imaging. Since most of these methods require tagging pulse and wait time for blood to be delivered to the imaged slice, the temporal resolution may not be optimal. Dynamic intravoxel incoherent motion (IVIM) weighting schemes using apparent diffusion coefficient (ADC) contrast were suggested to image the relative changes of the in‐plane blood flow during brain function. In this report, it was demonstrated that, in addition to the spatial discrepancies of the activated areas, the time course based on the ADC contrast consistently precedes that from the BOLD contrast with timing offset on the order of 1 sec. Since arterial networks would have different spatial locations and preceding temporal characters, the findings in this report are indicative that the ADC contrast is sensitive to the arterial blood flow changes. Magn Reson Med 48:385–388, 2002. © 2002 Wiley‐Liss, Inc.
Characterization and reduction of gradient‐induced eddy currents in the RF shield of a TEM resonator
Authors: Alecci Marcello , Jezzard Peter 
Published: October 2002

AbstractRadiofrequency (RF) shields that surround MRI transmit/receive coils should provide effective RF screening, without introducing unwanted eddy currents induced by gradient switching. Results are presented from a detailed examination of an effective RF shield design for a prototype transverse electromagnetic (TEM) resonator suitable for use at 3 Tesla. It was found that effective RF shielding and low eddy current sensitivity could be achieved by axial segmentation (gap width = 2.4 mm) of a relatively thick (35 μm) copper shield, etched on a kapton polyimide substrate. This design has two main advantages: first, it makes the TEM less sensitive to the external environment and RF interference; and second, it makes the RF shield mechanically robust and easy to handle and assemble. Magn Reson Med 48:404–407, 2002. © 2002 Wiley‐Liss, Inc.
Macrophage apoptosis in rat skeletal muscle treated with bupivacaine hydrochloride: Possible role of MCP‐1
Authors: Horiguchi Taisuke , Shibata Masa‐Aki , Ito Yuko , Eid Nabil A.S. , Abe Muneaki , Otsuki Yoshinori 
Published: October 2002

AbstractThe fate of macrophages infiltrating damaged rat skeletal muscle fibers after intramuscular injection of the anesthetic bupivacaine hydrochloride (BPVC) and the possible roles of monocyte chemoattractant protein–1 (MCP‐1) were investigated. The number of macrophages reached a maximum level at 2 days after the injection and then gradually decreased. The number of apoptotic cells detected by terminal deoxynucleotidyl transferase–mediated dUTP nick‐end labeling (TUNEL) assay was elevated at 2–4 days and decreased thereafter. In serial sections, TUNEL‐positive cells were also immunopositive for RM‐4, an antibody specific for identification of macrophages. Electron microscopy further confirmed that it was the macrophages themselves that were undergoing apoptosis. As assessed by reverse transcriptase–polymerase chain reaction (RT‐PCR), high levels of MCP‐1 mRNA in BPVC‐treated muscles were observed and positively correlated with maximum macrophage infiltration. However, the levels of MCP‐1 mRNA returned to normal low values coincident with decrease of inflammation and healing of damaged muscle fiber. Local apoptosis of macrophages, under the control of MCP‐1, may be involved in healing of BPVC‐treated muscles. © 2002 Wiley Periodicals, Inc. Muscle Nerve 26: 79–86, 2002
A self‐adapting genetic algorithm for project scheduling under resource constraints
Authors: Hartmann Sönke 
Published: October 2002

AbstractThis papers deals with the classical resource‐constrained project scheduling problem (RCPSP). There, the activities of a project have to be scheduled subject to precedence and resource constraints. The objective is to minimize the makespan of the project. We propose a new heuristic called self‐adapting genetic algorithm to solve the RCPSP. The heuristic employs the well‐known activity list representation and considers two different decoding procedures. An additional gene in the representation determines which of the two decoding procedures is actually used to compute a schedule for an individual. This allows the genetic algorithm to adapt itself to the problem instance actually solved. That is, the genetic algorithm learns which of the alternative decoding procedures is the more successful one for this instance. In other words, not only the solution for the problem, but also the algorithm itself is subject to genetic optimization. Computational experiments show that the mechanism of self‐adaptation is capable to exploit the benefits of both decoding procedures. Moreover, the tests show that the proposed heuristic is among the best ones currently available for the RCPSP. © 2002 Wiley Periodicals, Inc. Naval Research Logistics 49: 433–448, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/nav.10029
Parallel NC‐algorithms for multifacility location problems with mutual communication and their applications
Authors: Averbakh Igor , Berman Oded 
Published: October 2002

AbstractThe generic problem studied is to locate p distinguishable facilities on a tree to satisfy upper‐bound constraints on distances between pairs of facilities, given that each facility must be located within its own feasible region, which is defined as a subtree of the tree. We present a parallel location scheme (PLS) for solving the problem that can be implemented as an NC‐algorithm. We also introduce parallel NC‐algorithms based on the PLS for the minimax versions of the problem, including the distance‐constrained p‐center problem with mutual communication. Combining the PLS and the improved Megiddo's parametric technique, we develop strongly polynomial serial algorithms for the minimax problems; the algorithms have the best complexities currently available in the literature. Efficient parallel algorithms are given for obtaining optimal regions of the facilities. © 2002 Wiley Periodicals, Inc.
A note on the traveling repairman problem
Authors: García Alfredo , Jodrá Pedro , Tejel Javier 
Published: October 2002

AbstractGiven a finite set of N nodes and the time required for traveling among nodes, in the traveling repairman problem, we seek a route that minimizes the sums of the delays for reaching each node. In this note, we present a linear algorithm for solving the traveling repairman problem when the underlying graph is a path, improving the Θ(N2) time and space complexity of the previously best algorithm for this problem. We also provide a linear algorithm for solving the walk problem with deadlines (WPD) on paths. © 2002 Wiley Periodicals, Inc.
Approximation algorithms for constructing wavelength routing networks
Authors: Hassin Refael , Levin Asaf 
Published: October 2002

AbstractConsider a requirement graph whose vertices represent customers and an edge represents the need to route a unit of flow between its end vertices along a single path. All these flows are to be routed simultaneously. A solution network consists of a (multi)graph on the same set of vertices, such that it is possible to route simultaneously all of the required flows in such a way that no edge is used more than K times. The SYNTHESIS OF WAVELENGTH ROUTING NETWORK (SWRN) problem is to compute a solution network of a minimum number of edges. This problem has significant importance in the world of fiber‐optic networks where a link can carry a limited amount of different wavelengths and one is interested in finding a minimum‐cost network such that all the requirements can be carried in the network without changing the wavelength of a path at any of its internal vertices. In this paper, we prove that the SWRN problem is NP‐hard for any constant K (K ≥ 2). Then, we assume that GR is a clique with n vertices and we find an “almost” optimal solution network for all values of K (K = o(n)) and present a Min{(K + 1)/2, 2 + 2/(K − 1)}‐approximation algorithm for the general case and a 2‐approximation algorithm for d‐regular graphs. © 2002 Wiley Periodicals, Inc.
Unified formulation of radiation conditions for the wave equation
Authors: Krenk Steen 
Published: October 2002

AbstractA family of radiation boundary conditions for the wave equation is derived by truncating a rational function approximation of the corresponding plane wave representation, and it is demonstrated how these boundary conditions can be formulated in terms of fictitious surface densities, governed by second‐order wave equations on the radiating surface. Several well‐established radiation boundary conditions appear as special cases, corresponding to different choices of the coefficients in the rational approximation. The relation between these choices is established, and an explicit formulation in terms of selected directions with ideal transmission is presented. A mechanical interpretation of the fictitious surface densities enables identification of suitable conditions at corners and boundaries of the radiating surface. Numerical examples illustrate excellent results with one or two fictitious layers with suitable corner and boundary conditions. Copyright © 2001 John Wiley & Sons, Ltd.
Two hybrid stress membrane finite element families with drilling rotations
Authors: Geyer Sannelie , Groenwold Albert A. 
Published: October 2002

AbstractTwo new assumed stress membrane finite element families with two translational and one rotational degree of freedom per node are presented. The families, denoted by 8β(M) and 8β(D), are rank sufficient and invariant, and are derived using a unified Hu–Washizu like variational formulation. A recent stress mode classification method is used to illustrate the construction of the stress interpolation matrices. In each family, a number of new formulations are derived. Numerical results are presented. Copyright © 2001 John Wiley & Sons, Ltd.
Shape optimization with hybrid‐Trefftz displacement elements
Authors: Teixeira de Freitas J. A. , Cismasiu I. 
Published: October 2002

AbstractThe displacement model of the hybrid‐Trefftz finite element formulation is applied to the shape optimization of linear elastostatic problems. The model is based on the direct approximation of the displacements in the domain of the element and of the tractions on its boundary. The independent description of the geometry is based on the parametric description of the shape of the element sides. The finite element solving system is symmetric and sparse. As the displacement approximation is extracted from the solution set of the governing differential equations, all structural matrices are defined by boundary integral expressions. The approximation bases are compact and naturally p‐hierarchical. High‐order approximations are implemented to obtain accurate solutions using coarse meshes of macro‐elements. The sensitivities are determined analytically and remeshing is not implemented during the optimization procedure because the elements are weakly sensitive to gross shape distortion. Numerical testing is based on a standard set of two‐dimensional linear elastostatic problems. Copyright © 2001 John Wiley & Sons, Ltd.
Hybrid time domain solvers for the Maxwell equations in 2D
Authors: Abenius Erik , Andersson Ulf , Edelvik Fredrik , Eriksson Lasse , Ledfelt Gunnar 
Published: October 2002

AbstractWe present a new approach to time domain hybrid schemes for the Maxwell equations. By combining the classical FD‐TD scheme with two unstructured solvers, one explicit finite volume solver and one implicit finite element solver, we achieve a very efficient and flexible second‐order scheme. The second‐order accuracy of the hybrid scheme is verified through convergence studies on perfectly conducting as well as dielectric and diamagnetic circular cylinders. The numerical results also show its superiority to the FD‐TD scheme. Copyright © 2002 John Wiley & Sons, Ltd.
Free vibration of sandwich plates with laminated faces
Authors: Yuan W. X. , Dawe D. J. 
Published: October 2002

AbstractDescription is given of the development of a spline finite strip method for predicting the natural frequencies and modes of conventional rectangular sandwich plates. The faceplates are treated as being classically thin and may be of composite laminated construction. The core is modelled as a three‐dimensional body. Finite strip stiffness and mass properties are based on a displacement field which represents eight fundamental through‐thickness displacements as a series of products of longitudinal B‐spline functions and crosswise Lagrangian or Hermitian polynominal shape functions. The solution procedure utilizes the efficient superstrip concept in conjunction with the extended Sturm sequence‐bisection approach. A variety of applications of the developed analysis capability is described which demonstrates the nature of the convergence of the finite strip predictions of natural frequencies and the close comparison of these predictions with available results in the literature, and also the use of the capability in parametric studies. Copyright © 2002 John Wiley & Sons, Ltd.
Stress analysis in continuous media with an edge dislocation by finite element dislocation model
Authors: Sasaki Kazuaki , Kishida Michiya , Ekida Yutaka 
Published: October 2002

AbstractIn this paper, a finite element dislocation model is proposed, based on well‐known mathematical dislocation model. As application examples, the stress distributions around an edge dislocation in infinite homogeneous and inhomogeneous regions are calculated and compared with the analytical results. The FEM results coincide well with the exact solutions. The results show an applicability and a usefulness of finite element dislocation model, and further, a possibility of analysing a dislocation problem in finite region with complicated shapes and boundary conditions. Copyright © 2002 John Wiley & Sons, Ltd.
Modelling friction near sharp edges using a Eulerian reference frame: application to aluminium extrusion
Authors: van Rens B. J. E. , Brekelmans W. A. M. , Baaijens F. P. T. 
Published: October 2002

AbstractWhen using a Eulerian finite element approach to model the material deformation that occurs in e.g. forming processes, the accurate capturing of friction is of crucial importance to the quality of the computational results. For the algorithm that incorporates the frictional phenomena into the system of equations, the direction of the contact surface normal in a node is an essential parameter. However, this normal is not uniquely defined in the nodes of a curved, discretized surface. Therefore, a substitute normal has to be reconstructed.The commonly used (averaging) methods to determine the normal are either mesh or geometry dependent which renders poor results on coarse meshes. Therefore, a new method is presented that reconstructs the direction of the normal from the flow field near the node. Comparing the flow fields on a coarse mesh with those obtained on a very fine mesh reveals that a more accurate solution field is obtained using the method introduced here. Copyright © 2002 John Wiley & Sons, Ltd.