bluuebunny/crossref_metadata_2025 huggingface dataset:
The possibility of dowel removal by pulsed Nd:YAG laser irradiation
Authors: Takashina Masaaki , Ebihara Arata , Sunakawa Mitsuhiro , Anjo Tomoo , Takeda Atsushi , Suda Hideaki
Published: October 2002

Background and Objectives

Nd:YAG laser is one of the popularly used laser, in dentistry for treatment and technologic processing. Removal of dowel from root canal is very troublesome at endodontic retreatment. This study aimed to examine the possibility and efficiency of dowel removal from the root canal using the Nd:YAG laser in vitro.

Study Design/Materials and Methods

Irradiation time and energies required for complete removal of the dowel set in the root canal using the laser were measured. The dowel ablation was observed by contact microradiographs (CMRs). The surface of the root canal after lasing was observed by a scanning electron microscope (SEM).

Results

A significant difference existed in irradiation times and energies to remove dowels among various combinations of metal and cement (P < 0.05). The CMRs showed that both dowel and dentin were ablated, and the SEM observation demonstrated that root canal surface was melted.

Conclusions

The Nd:YAG laser irradiation could remove set dowels from the root canal. Lasers Surg. Med. 31:268–274, 2002. © 2002 Wiley‐Liss, Inc.
Alterations of the retinoblastoma‐related gene RB2/p130 in lung adenocarcinomas induced by N‐nitrosobis(2‐hydroxypropyl)amine in rats
Authors: Tsujiuchi Toshifumi , Sasaki Yasutaka , Konishi Yoichi , Tsutsumi Masahiro
Published: October 2002

Alteration of the retinoblastoma‐related gene RB2/p130 was investigated in lung adenocarcinomas induced by N‐nitrosobis(2‐hydroxypropyl)amine (BHP) in male Wistar rats. At 6 wk of age, 21 animals were given 2000 ppm of BHP in their drinking water for 12 wk and then maintained without further treatment until they were killed at the end of week 25. A total of 21 lung adenocarcinomas were obtained, and total RNAs were extracted from each for mutation analysis of RB2/p130 by the reverse transcription–polymerase chain reaction–single‐strand comformation polymorphism approach. No mutations were found in exons 19–22. However, examination of the expression of the RB2/p130 gene by Northern blot analysis showed mRNA levels to be significantly lower than those of normal lung tissues. Western blot analysis showed reduction of the pRb2/p130 protein in all of the adenocarcinomas examined. These results suggest that alteration of the RB2/p130 gene may play important roles in the development of lung adenocarcinomas induced by BHP in rats. © 2002 Wiley‐Liss, Inc.
The hyperkinetic abnormal movements scale: A tool for measuring levodopa‐induced abnormal movements in squirrel monkeys
Authors: Tan Louis C. , Protell Peter H. , Langston J. William , Togasaki Daniel M.
Published: October 2002

The Hyperkinetic Abnormal Movements Scale (HAMS) was developed based on extensive observation of normal and abnormal movements in squirrel monkeys. The observations of abnormal movements were performed using animals that had undergone prior lesioning with 1‐methyl‐4‐phenyl‐1,2,3,6‐tetrahydropyridine (MPTP) that subsequently developed levodopa‐induced abnormal movements. Specific and easily observable changes in behavior were used to delineate the boundaries between each rating level of the scale. The full spectrum of abnormal behavior at each rating level was then characterized for the squirrel monkey. Once the scale was fully developed and finalized, reliability testing revealed strong inter‐rater (r = 0.959) and intrarater reliability (r = 0.930 to 0.941). Novice raters were easily taught its use and subsequently could use the scale with strong inter‐rater reliability (R = 0.9057). In further studies of levodopa‐induced abnormal movements, the HAMS was demonstrated to be highly sensitive, highly specific, and valid, both internally and when compared with an objective measure of abnormal movements. Although the scale was developed in MPTP‐lesioned squirrel monkeys treated with levodopa, it might provide a framework for the standardized measurement of hyperkinetic abnormal movements in other primates and other experimental conditions. © 2002 Movement Disorder Society
Quasi‐static analysis of microstriplines with variable‐thickness substrates considering finite metallization thickness
Authors: Khoulji S. , Essaaidi M.
Published: October 2002

This Letter presents an extension of the method of lines (MOL) to the analysis of microstriplines with variable‐thickness substrates with the use of the quasi‐static approximation. Discretization lines of varying length, according to the layer thickness, are used. Only Laplace wave equation have to be solved. The numerical results presented here permit illustration of the effect of arbitrary curved interfaces on the considered structures. As an example, the characteristic impedance, the capacitance PUL, the inductance PUL, and the effective dielectric constant are computed as a function of different shape characteristics of these microstripline structures. The effect of metallization thickness is also included in the analysis. The results show good agreement with data available in the literature. © 2002 Wiley Periodicals, Inc. Microwave Opt Technol Lett 33: 19–22, 2002; DOI 10.1002/mop.10218
Coupling reduction between slanted shipboard antennas
Authors: Lee Sung‐Shin , Park Hae‐Sung , Bang Jin‐Gyu , Kim Hyo‐Tae
Published: October 2002

In this article, mitigation techniques for antenna coupling levels are introduced. Each antenna is slanted for the polarization mismatch. This reduces the coupling level between co‐frequency band antennas. Antenna radiation patterns are also considered as a parameter of antenna performances. In all, 30 antenna arrangements are analyzed. Each arrangement gives its coupling level and radiation pattern. With these parameters, one can be determine which arrangement is better from electromagnetic compatibility point of view. © 2002 Wiley Periodicals, Inc. Microwave Opt Technol Lett 33: 37–40, 2002
Measured equation of invariance based on wavelet transform technique
Authors: Lee Byungje , Harackiewicz Frances J. , Lee Jong‐Chul , Kim Jong‐Heon , Kim Nam‐Young
Published: October 2002

Wavelets have been applied in conjunction with the measured equation of invariance (MEI) to solve a two‐dimensional scattering problem. The MEI method with wavelet metrons is referred to as the wavelet MEI method. Haar wavelets are used as metrons. The proposed method leads to a significant savings in CPU time compared to the standard MEI method that does not use wavelets as metrons. © 2002 Wiley Periodicals, Inc. Microwave Opt Technol Lett 33: 47–49, 2002; DOI 10.1002/mop.10227
High performance double‐sided microstrip PBG filter
Authors: Akalin T. , Laso M. A. G. , Delos E. , Lopetegi T. , Vanbésien O. , Sorolla M. , Lippens D.
Published: October 2002

Microwave filters in microstrip technology have been designed by taking advantage of metal patterning of the front and back‐side planes. It is shown that such an approach with drilled holes in the ground plane for the high impedance sections permits one to alleviate some of the drawbacks associated with uniplanar impedance modulated filters with high geometric aspect ratios. Prototypes for the S and C‐bands were fabricated by conventional low‐cost printed circuit techniques and show improved performances in terms of rejection and bandwidth. © 2002 Wiley Periodicals, Inc. Microwave Opt Technol Lett 35: 90–93, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10525
Analysis of electromagnetic scattering from periodic structures by FEM truncated by anisotropic PML boundary condition
Authors: Cui Suomin , Weile Daniel S.
Published: October 2002

A method is presented for modeling open periodic structures by using the finite element method truncated by an anisotropic perfectly matched layer (PML). The method can be used to simulate periodic structures with inhomogeneous profile and arbitrary geometries. The PML is shown to be an effective method for mesh termination, even in the presence the grazing and evanescent fields generated by periodic structures. Numerical analysis is conducted for validation and to demonstrate the effectiveness of the proposed method. © 2002 Wiley Periodicals, Inc. Microwave Opt Technol Lett 35: 106–110, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10530
A simple method for the determination of noise coefficients P, R, and C by two port noise parameters
Authors: Chen Ping‐Yu , Lu Shey‐Shi , Wang Huei
Published: October 2002

In this paper, a simple method for the determination of noise coefficients P, R, and C by standard two‐port noise parameters, Fmin, RN and Γopt is presented. The relation between equivalent noise resistance RN and equivalent noise conductance gn has been derived, which greatly simplifies the extraction procedure. This method has been applied to the extraction of Kg/Kc/Kr and P/R/C from 0.15 μm InGaAs PHEMT's with three different sizes at two different biases. Excellent agreement between measured and calculated noise parameters has been found. The tendency of the extracted values with respect to device size and bias is also discussed. © 2002 Wiley Periodicals, Inc. Microwave Opt Technol Lett 35: 129–132, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10536
Experimental analysis of temporal variations in indoor radio channels at 1.8 GHz
Authors: Loredo Susana , Torres Rafael P.
Published: October 2002

This paper presents the results of a measurement campaign carried out with the aim of analysing the impact of people movement and activities on the indoor radio propagation channel at the frequency of 1.8 GHz. For that, the temporal variations of the channel between fixed terminals are measured in several propagation environments, in which usually different degrees of activity take place, allowing the definition of different canonical environments. From the measured data, the figures and statistical parameters that characterise each of the environments under study are extracted and analysed, in order to be able to associate the results obtained with the density of motion and extrapolate that information to other similar environments. The results can be useful for the design of new systems such as WPANs and for the development of a model that considers both the effects of spatial and temporal variations. © 2002 Wiley Periodicals, Inc. Microwave Opt Technol Lett 35: 132–137, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10537
Analytical method to compute metallic photonic band‐gap radar cross section
Authors: Collardey S. , Pouliguen P. , Mahdjoubi K. , Desclos L. , Tarot A.‐C.
Published: October 2002

The electromagnetic scattering by Metallic Photonic Band‐Gap materials, composed of cylindrical wires, is considered. A fast and accurate analytical method is proposed to compute the radar cross section of such structures with or without defects. Results are given and compared with success to those of numerical methods. © 2002 Wiley Periodicals, Inc. Microwave Opt Technol Lett 35: 145–150, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10542
Application of preconditioned Krylov subspace iterative FFT techniques to method of lines for analysis of the infinite plane metallic grating
Authors: Chen R. S. , Yung Edward K. N. , Yang A. H. , Chan C. H.
Published: October 2002

In this paper, both fast Fourier transformation (FFT) and preconditioned iterative solvers are introduced into method of lines (MOL) to further enhance the computational efficiency of this semi‐analytic method. Electromagnetic wave scattering by an infinite plane metallic grating is used as the examples to describe its implementation. For arbitrary incident wave, Helmholz equation and boundary condition are first transformed into new ones so that the impedance matrix elements is calculated by FFT technique. As a result, this Topelitz impedance matrix only requires O(N) memory storage for the Krylov subspace iterative‐FFT method to solve the current distribution involving the computational complexity O(N log N). The banded diagonal impedance matrix is selected as preconditioner to speed up the convergence rate of the Krylov subspace iterative algorithms. Our numerical results show that the preconditioned Krylov subspace iterative‐FFT method converges to accurate solution in much smaller CPU time. © 2002 Wiley Periodicals, Inc. Microwave Opt Technol Lett 35: 160–167, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10546
Determination of dielectric constant and loss‐tangent of substrate sheet using microstrip patch resonator
Authors: Verma A. K. , Nasimuddin
Published: October 2002

This paper presents a new microstrip rectangular patch resonator based method to determine the dielectric constant and the loss tangent of a dielectric material in sheet form. Using an improved form of the cavity model, called the modified Wolff model (MWM), the present method extracts these two parameters from the measured resonance frequency and Q‐factor. The MWM takes care of all kind of losses in the patch, resulting in accurate determination of the dielectric constant and loss tangent of the substrate. © 2002 Wiley Periodicals, Inc. Microwave Opt Technol Lett 35: 175–179, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10549
Efficient moment method solution for a shielded two arc type wires transmission line
Authors: Diveker E. , Levi S. , Matzner H. , Nissan H.
Published: October 2002

A transmission line based on two thin arc shaped conductors shielded by a circular conductor is solved efficiently by the moment method (MM). It is shown that two expansion functions are enough for an excellent convergence rate of the characteristic impedance. Design curves are given. © 2002 Wiley Periodicals, Inc. Microwave Opt Technol Lett 35: 195–198, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10555
Beamforming strategies for compact arrays in mobile terminals using the exact active element pattern method
Authors: Rogier Hendrik , De Zutter Daniël
Published: October 2002

Some beamforming strategies are presented for compact arrays in wireless systems. To rigorously account for mutual coupling, we rely on the exact active element pattern method. By considering a compact and low‐cost array operating in the HiperLAN band, it is shown that the proposed method allows null steering and beam steering. © 2002 Wiley Periodicals, Inc. Microwave Opt Technol Lett 35: 201–203, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10557
Reconstruction of non‐minimum phase function from only amplitude data
Authors: Koh Jinhwan , Cho Young‐ki , Sarkar Tapan K.
Published: October 2002

A procedure for a non‐minimum‐phase reconstruction from magnitude data alone is presented. A non‐minimum‐phase component is recovered, based on the fact that the auto‐correlation of the time domain sequence is equal to a discrete cosine transformation of the square of the magnitude response. An all‐pass filter is also utilized in order to reduce the optimization variables. Since a non‐minimum‐phase reconstruction does not have a unique solution, a causal time‐domain response is selected along with the smallest poles in magnitude. This theory is applied to antenna pattern synthesis and scattering parameters of microwave filters to illustrate the applicability of the proposed approach. © 2002 Wiley Periodicals, Inc. Microwave Opt Technol Lett 35: 212–216, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10560
PIFA‐monopole internal mobile phone antenna for GSM/DCS/PCS triple‐band operations
Authors: Yeh Shih‐Huang , Fang Chi‐Yin , Wong Kin‐Lu
Published: October 2002

A novel internal mobile phone antenna comprising a planar inverted‐F antenna (PIFA) and a low‐profile planar monopole, which are designed, respectively, for covering the DCS/PCS and GSM bands, is proposed in this paper. The PIFA and the planar monopole together occupy a compact volume of 6.8 × 7.0 × 34 mm3, and are suitable to be built‐in within the housing of a mobile phone. In addition, both the PIFA and the planar monopole have simple structures, which makes the proposed antenna easy to design and implement with a relaxed fabrication tolerance. A prototype of the proposed antenna was constructed and experimentally studied. © 2002 Wiley Periodicals, Inc. Microwave Opt Technol Lett 35: 217–219, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10561
Hybrid mode analysis of microstrip lines by the method of lines with pseudospectral discretization
Authors: Chen R. S. , Fan Z. H. , Yung Edward K. N. , Chan C. H.
Published: October 2002

In this paper, the method of lines (MoLs), which has been proved to be very efficient for calculating the characteristics of one‐dimensional and two‐dimensional planar microwave structures, is extended to nonequidistant discretization with pseudospectral technique. This pseudospectral MoLs is developed by combining pseudospectral technique and the MoLs, so that its solution is not only analytical along line direction, but also maintains high accuracy in discrete direction. A pseudospectral‐based discretization strategy, distribution of collocation nodes, global power series interpolation of differential quadrature, second‐order difference matrix, and decoupling of coupled ordinary differential equations are discussed in detail. The convergence behaviors are provided for line discretization, based on both the pseudospectral strategy and the second‐order finite difference (FD), respectively. The calculated results are compared with those published in the previous literature and our numerical results show that accuracy is improved with reduced computational effort for the analysis of microstrip lines. © 2002 Wiley Periodicals, Inc. Microwave Opt Technol Lett 35: 224–227, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10563
Isoquinoline alkaloids: a 15N NMR and x‐ray study. Part 2
Authors: Marek Radek , Marek Jaromír , Dostál Jiří , Táborská Eva , Slavík Jiří , Dommisse Roger
Published: October 2002

Continuing our systematic 15N NMR study of isoquinoline alkaloids, we report a contribution extending our previous paper. The 15N NMR chemical shifts and 15N,1H long‐range coupling pathways of tertiary and quaternary isoquinoline alkaloids of several constitutional types are presented. The selected compounds belong to the protoberberine, proaporphine, pavinane, rhoeadine and phtalideisoquinoline classes of alkaloids and were investigated by gradient‐selected inverse‐detected multiple bond correlation experiments (GHMBC and GSQMBC). In addition, x‐ray data and the principal geometric parameters of stylopine, mecambridine, norchelerythrine, isothebaine and mecambrine are reported and discussed. Copyright © 2002 John Wiley & Sons, Ltd.
Quantitative determination of aliphatic hydrocarbon compounds by 2D NMR
Authors: Koskela H. , Väänänen T.
Published: October 2002

Quantitative analysis of complex mixtures by NMR is often hampered by heavily overlapping signals in 1D 1H or 13C spectra. To resolve the overlap problem, we have been looking at the possibilities of using heteronuclear correlated 2D NMR methods for quantification. In this work, we applied 2D INEPT to analyze mixtures of tetradecane and squalane, which represent typical substructures of lube oil fractions. The factors affecting correlation peak volumes, namely the polarization transfer delays within pulse sequence, multiplicity of CHn group and the magnitude of 1J(C, H) couplings were taken into account by product operator formalism calculations. The results indicate that if absolute precision in quantification is not essential, the current approach can be used for the quantitative analysis of the molecular composition of complex mixtures when conventional 1D NMR methods fail. Copyright © 2002 John Wiley & Sons, Ltd.
Stimulation of the murine type II transforming growth factor‐β receptor promoter by the transcription factor Egr‐1
Authors: Wilder Phillip J. , Bernadt Cory T. , Kim Jae‐Hwan , Rizzino Angie
Published: October 2002

Previous studies have demonstrated that differentiation of murine embryonal carcinoma (EC) cells leads to the appearance of high affinity receptors for transforming growth factor‐β (TGF‐β). Subsequently, it was demonstrated that differentiation of F9 EC cells leads to increases in the transcription of the type II TGF‐β‐receptor gene (TβR‐II) and leads to significant increases in the steady‐state levels of TβR‐II mRNA. Analysis of the human TβR‐II promoter in F9‐differentiated cells identified several cis‐regulatory elements that influence the activity of the promoter, including a CRE/ATF site and a CCAAT box motif. In the work described in this report, we focused on the effect of the transcription factor Egr‐1 on the murine TβR‐II promoter. We have identified an Egr‐1 response‐element ∼150 bp upstream of the major transcription start site of the murine TβR‐II gene. We demonstrate by electrophoretic mobility shift analysis (EMSA) that this cis‐regulatory element binds Egr‐1, and we demonstrate that disruption of this site eliminates the response to Egr‐1. As part of this analysis, we also examined the effect of Egr‐1 on human TβR‐II promoter. In contrast to a previous report, which reported that Egr‐1 inhibits expression of human TβR‐II promoter/reporter gene constructs, we did not observe an inhibitory effect of Egr‐1 that was specific for the human TβR‐II promoter. Taken together, the findings described in this report identify important differences between the human and the murine TβR‐II promoter, and our findings identify an Egr‐1 cis‐regulatory element that is capable of stimulating the activity of the murine TβR‐II promoter. Mol. Reprod. Dev. 63: 282–290, 2002. © 2002 Wiley‐Liss, Inc.
Expression and characterization of functional recombinant bovine follicle‐stimulating hormone (boFSHα/β) produced in the milk of transgenic rabbits
Authors: Coulibaly S. , Besenfelder U. , Miller I. , Zinovieva N. , Lassnig C. , Kotler T. , Jameson J.L. , Gemeiner M. , Müller M. , Brem G.
Published: October 2002

Bovine follicle‐stimulating hormone (boFSH) is a heterodimeric glycoprotein that belongs to the pituitary gonadotropins. Bioactive FSH is composed of α and β subunits which require extensive N‐glycosylation and sialylation. The mammary gland of transgenic livestock is an attractive source for the synthesis of post‐translationally modified proteins. Two mammary gland‐specific gene constructs with the cDNA for the boFSH alpha (boFSHα) and beta (boFSHβ) subunits controlled by bovine alpha‐s1 casein regulatory sequences were co‐microinjected into fertilized rabbit oocytes. Two FSHα/FSHβ double transgenic rabbit lines were established. The transgene expression was strictly lactation and mammary gland specific. Protein analysis revealed the presence of the boFSH heterodimer in the milk of transgenic rabbits showing a molecular weight similar to that of purified pituitary gland derived boFSH (boFSH‐P). Subunit specific antibodies detected both polypeptides with the expected molecular sizes. Biochemical characterization demonstrated the expected isoelectric points of the recombinant boFSH. The presence of the post‐translationally added terminal sialic acid residues was indicated by wheat germ agglutinin (WGA) lectin Western blotting. The biological activity of the recombinant mammary gland produced boFSH was determined using a FSH‐dependent reporter cell line. The bioactivity of the recombinant boFSH was comparable to that of purified boFSH‐P. Mol. Reprod. Dev. 63: 300–308, 2002. © 2002 Wiley‐Liss, Inc.
Histone H1‐like protein and a testis‐specific variant in the reproductive tracts of Octopus vulgaris
Authors: Mennella Maria Rosaria Faraone , Farina Benedetta , Irace Maria Venezia , Cristo Carlo Di , Cosmo Anna Di
Published: October 2002

In this study, we have identified a 28‐kDa protein resembling the linker H1 in the testis and prostate of the reproductive system of Octopus vulgaris. This protein, OvH1, was partially purified by reverse phase high‐pressure liquid chromatography (HPLC) of the perchloric acid extract from testis nuclei. It showed electrophoretic mobility, CD spectrum and amino acid composition highly comparable with those of the mammalian histone. Moreover, it was microheterogeneous, as resulted from prostate and testis HPLC and mass spectrometry analyses. Such analysis showed that in testis there are two H1 subfractions, which do not appear in the prostate. Amino acid composition of the major testis specific variant (OvH1t) showed high similarity with rat testis specific H1t. The histone‐like nature of OvH1 was confirmed by its ability to bind DNA as tested both by circular dichroism and protection of the nucleic acid toward deoxyribonuclease I activity. The circular dichroism spectra of Octopus DNA in the absence and presence of increasing amounts of the protein showed a dose‐dependent effect, leading to a progressive compactness of the polynucleotide. OvH1/DNA complexes were also resistant to nuclease digestion. The presence of H1 in the testis and prostate of the reproductive system of Octopus is discussed in light of the fact that there is a similarity between its behavior and that of vertebrates. Mol. Reprod. Dev. 63: 355–365, 2002. © 2002 Wiley‐Liss, Inc.
High‐resolution, spin‐echo BOLD, and CBF fMRI at 4 and 7 T
Authors: Duong Timothy Q. , Yacoub Essa , Adriany Gregory , Hu Xiaoping , Ugurbil Kamil , Vaughan J. Thomas , Merkle Hellmut , Kim Seong‐Gi
Published: October 2002

With growing interest in noninvasive mapping of columnar organization and other small functional structures in the brain, achieving high spatial resolution and specificity in fMRI is of critical importance. We implemented a simple method for BOLD and perfusion fMRI with high spatial resolution and specificity. Increased spatial resolution was achieved by selectively exciting a slab of interest along the phase‐encoding direction for EPI, resulting in a reduced FOV and number of phase‐encoding steps. Improved spatial specificity was achieved by using SE EPI acquisition at high fields, where it is predominantly sensitive to signal changes in the microvasculature. Robust SE BOLD and perfusion fMRI were obtained with a nominal in‐plane resolution up to 0.5 × 0.5 mm2 at 7 and 4 Tesla, and were highly reproducible under repeated measures. This methodology enables high‐resolution and high‐specificity studies of functional topography in the millimeter to submillimeter spatial scales of the human brain. Magn Reson Med 48:589–593, 2002. © 2002 Wiley‐Liss, Inc.
Human erythrocyte ghosts: Exploring the origins of multiexponential water diffusion in a model biological tissue with magnetic resonance
Authors: Thelwall Peter E. , Grant Samuel C. , Stanisz Greg J. , Blackband Stephen J.
Published: October 2002

A tissue model composed of erythrocyte ghosts was developed to study the effects of compartmentation on the MR signal acquired from biological tissues. This simple and flexible model offers control over the biophysical parameters that contribute to multicomponent signals arising from cellular systems. Cell density, size, intra‐ and extracellular composition, and membrane permeability can be independently altered. The effects of cell density and cell size on water diffusion properties were assessed. The data demonstrate non‐monoexponential water diffusion in ghost cell suspensions of 17–67% cell density. Data were analysed with the widely employed two‐compartment (biexponential) model, and with a two‐compartment model that accounted for exchange between compartments. Water exchange between the intra‐ and extracellular compartments appeared to be significant over the range of diffusion times studied (7–35 ms). The biexponential fit to the ghost data appeared to be underparameterised as the ADCs and relative fractions of the fast and slow components were dependent on the experimental acquisition parameters, specifically the diffusion time. However, both analysis methods proved effective at tracking changes in the ghost model when it was perturbed. This was demonstrated with cell density variation, cell swelling and shrinkage experiments, and reduction of membrane water permeability using a water channel blocker (pCMBS). We anticipate that this model system could be used to investigate compartmental diffusion effects to simulate a range of pathologies, especially ischemic stroke. Magn Reson Med 48:649–657, 2002. © 2002 Wiley‐Liss, Inc.
Quadriplegic areflexic ICU illness: Selective thick filament loss and normal nerve histology
Authors: Sander Howard W. , Golden Marianna , Danon Moris J.
Published: October 2002

Areflexic quadriplegia that occurs in the intensive care unit (ICU) is commonly ascribed to critical illness polyneuropathy based upon electrophysiology or muscle light microscopy. However, electron microscopy often documents a selective thick filament loss myopathy. Eight ICU patients who developed areflexic quadriplegia underwent biopsy. Seven patients had received steroids, and 2 had also received paralytic agents. Electrodiagnostic studies revealed absent or low‐amplitude motor responses in 7. Sensory responses were normal in 5 of 6 and absent in 1. Initial electromyography revealed absent (n = 3), small (n = 3), or polyphasic (n = 1) motor unit potentials, and diffuse fibrillation potentials (n = 5). In all 8, light microscopy of muscle revealed numerous atrophic‐angulated fibers and corelike lesions, and electron microscopy revealed extensive thick filament loss. Morphology of sural and intramuscular nerves, and, in one autopsied case, of the obturator nerve and multiple nerve roots, was normal. Although clinical, electrodiagnostic, and light microscopic features mimicked denervating disease, muscle electron microscopy revealed thick filament loss, and nerve histology was normal. This suggests that areflexic ICU quadriplegia is a primary myopathy and not an axonal polyneuropathy. © 2002 Wiley Periodicals, Inc. Muscle Nerve 26: 499–505, 2002
Allotransplanted nerves regenerate inhibitory synapses on a crayfish muscle: Possible postsynaptic specification
Authors: Govind C.K. , Coulthard Rosalind , Pearce Joanne
Published: October 2002

Donor nerves of different origins, when transplanted onto a previously denervated adult crayfish abdominal superficial flexor muscle (SFM), regenerate excitatory synaptic connections. Here we report that an inhibitory axon in these nerves also regenerates synaptic connections based on observation of nerve terminals with irregular to elliptically shaped synaptic vesicles characteristic of the inhibitory axon in aldehyde fixed tissue. Inhibitory terminals were found at reinnervated sites in all 12 allotransplanted‐SFMs, underscoring the fact that the inhibitory axon regenerates just as reliably as the excitatory axons. At sites with degenerating nerve terminals and at sparsely reinnervated sites, we observe densely stained membranes, reminiscent of postsynaptic membranes, but occurring as paired, opposing membranes, extending between extracellular channels of the subsynaptic reticulum. These structures are not found at richly innervated sites in allotransplanted SFMs, in control SFMs, or at several other crustacean muscles. Although their identity is unknown, they are likely to be remnant postsynaptic membranes that become paired with collapse of degenerated nerve terminals of excitatory and inhibitory axons. Because these two axons have uniquely different receptor channels and intramembrane structure, their remnant postsynaptic membranes may therefore attract regenerating nerve terminals to form synaptic contacts selectively by excitatory or inhibitory axons, resulting in postsynaptic specification. © 2002 Wiley Periodicals, Inc. J Neurobiol 53: 80–89, 2002
Sobolev space preconditioning for Newton's method using domain decomposition
Authors: Axelsson O. , Faragó I. , Karátson J.
Published: October 2002

An inner–outer iteration is constructed for ill‐conditioned non‐linear elliptic boundary value problems, using a damped inexact Newton Method for the outer and a conjugate gradient method for the inner iteration. The focus is on efficient preconditioning for the inner iteration. Sobolev space background is used to construct preconditioners as discretizations of appropriately chosen piecewise constant coefficient elliptic operators. The combination of this theoretical approach with a suitable domain decomposition idea results in well‐structured preconditioners that are able to compensate for the sharp gradients of the coefficients. Furthermore, convergence estimates and mesh independence of the condition numbers are direct consequences of the method. Copyright © 2002 John Wiley & Sons, Ltd.
Discrete singular convolution and its application to the analysis of plates with internal supports. Part 2: Applications
Authors: Xiang Y. , Zhao Y. B. , Wei G. W.
Published: October 2002

Part 2 of this series of two papers presents the applications of the discrete singular convolution (DSC) algorithm. The main purpose of this paper is to explore the utility, test the accuracy and examine the convergence of the proposed approach for the vibration analysis of rectangular plates with internal supports. Both partial internal line supports and complex internal supports are considered for 21 square plates of various combinations of edge support conditions. The effects of different size, shape and topology of the internal supports and different boundary conditions on the vibration response of plates are investigated. The partial internal line supports may vary from a central point support to a full range of cross or diagonal line supports. Several closed‐loop supports, such as ring, square and rhombus, and their combinations are studied for complex internal supports. Convergence and comparison studies are carried out to establish the correctness and accuracy of the DSC algorithm. The DSC results are compared with those in the available literature obtained by using other methods. Numerical results indicate that the DSC algorithm exhibits controllable accuracy for plate analysis and shows excellent flexibility in handling complex geometries, boundary conditions and support conditions. Copyright © 2002 John Wiley & Sons, Ltd.
Numerical study of consistency of rate constitutive equations with elasticity at finite deformation
Authors: Lin Ruocheng
Published: October 2002

The present work is concerned with the numerical study of the elasticity consistency of the spatial rate equations using the conventional Oldroyd, Truesdell, Cotter–Rivlin, Jaumann and Green–Naghdi rates and the three novel co‐rotational ΩE‐ and Ω¯L‐based, logarithmic rates, and of the rotated material rate equation describing the relationship between the material time derivatives of the rotated Kirchhoff stress and material logarithmic strain. To this end, three integration procedures for updating stress are presented. The stress responses of several typical deformation processes are simulated. According to the numerical results we know that among the spatial rate equations only the logarithmic rate equation is consistent with elasticity under constant material parameters. Integrating the other spatial rate equations will provide path‐dependent stress response. These numerical conclusions support the arguments in H. Xiao et al. (Acta Mechanica 1999; 138:31–50). The reasons leading to elasticity inconsistency of spatial rate equations are analysed. If the material parameters are assumed to be strain‐dependent, the logarithmic rate equation loses also its elasticity‐consistent property. The numerical results prove also that the spatial logarithmic and rotated material rate equations are equivalent to each other. Copyright © 2002 John Wiley & Sons, Ltd.
Sensorless DC motor drive via optimal observer‐based servo control
Authors: Leephakpreeda Thananchai
Published: October 2002

This paper proposes an alternative design of a sensorless DC motor drive via optimal observer‐based servo control. Without the speed sensor, the extended Luenberger observer is implemented to estimate the rotor speed of the DC motor in the presence of the disturbance torque. With this knowledge of the speed estimated from the observer, the servo state‐feedback controller can drive such a rotor speed to follow the desired one. The stability and performance of the DC drive system can be guaranteed by the optimal control which minimizes the H2 norm of the closed‐loop feedback control and observer system. The simulation and experiment studies are demonstrated for the effectiveness of the proposed control methodology in a practical approach for the sensorless DC drive. Copyright © 2002 John Wiley & Sons, Ltd.
Gamma radiation induced graft copolymerization of acrylamide onto EPDM blended with PE
Authors: El‐Nesr E. M.
Published: October 2002

Gamma radiation induced grafting of acrylamide (AAm) onto vulcanized strips of EPDM and EPDM/PE blends has been carried out. The effects of different parameters on the graft yield have been investigated. These parameters include: radiation dose, monomer concentration, diluent composition and types of inhibitors. It has been found that water is the most appropriate solvent. The preswelling of crosslinked rubber samples in cyclohexane prior to grafting enhances the grafting and the addition of methanol to water as binary diluent in the ratio (1 : 1) decreases the graft yield. The presence of Mohr's salt and copper sulfate in the reaction mixture in the molar ratio (2.1 : 0.5) markedly increases the graft yield. Evidence of grafting have been conducted using thermal analysis as well as swelling measurements in water. Also, it has been found that the mechanical properties of the blends decrease at graft yield 13%. Copyright © 2002 John Wiley & Sons, Ltd.
Epoxy‐functionalized, low‐glass‐transition‐temperature latex. II. Interdiffusion versus crosslinking in the presence of a diamine
Authors: Tronc Frédéric , Chen Warner , Winnik Mitchell A. , Eckersley Sarah T. , Rose Gene D. , Weishuhn J. M. , Meunier D. M.
Published: October 2002

This article describes the results of experiments examining the competition between the polymer diffusion rate and the crosslinking rate in low‐glass‐transition‐temperature, epoxy‐containing latex films in the presence of a diamine. We examined films formed from donor‐ and acceptor‐labeled poly(butyl acrylate‐co‐methyl methacrylate‐co‐glycidyl methacrylate) copolymer latex and studied the influence of several parameters on the growth rate of gel content and the rate of polymer diffusion. These factors include the molecular weight of the latex polymer, the presence or absence of a diamine crosslinking agent, and the cure protocol. The results were compared to the predictions of a recent theory of the competition between crosslinking and polymer diffusion across interfaces. In the initially formed films, polymer diffusion occurs more rapidly than the chemical reaction rate. Therefore, these films fall into the fast‐diffusion category of this model. In our system (unlike in the model), the latex polymer has a broad distribution of molecular weights and a distribution of diffusivities. The shortest chains contribute to the early time diffusion that we measure. At later stages of our experiment, slower diffusing species contribute to the signal that we measure. The diffusion time decreases substantially, and we observe a crossover to a regime in which the chemical reaction dominates. The increases in chain branching and gel formation bring polymer diffusion to a halt. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 4098–4116, 2002
Fluoropolyethers end‐capped by polar functional groups. III. Kinetics of the reactions of hydroxy‐terminated fluoropolyethers and model fluorinated alcohols with cyclohexyl isocyanate catalyzed by organotin compounds
Authors: Mashlyakovskiy Leonid , Khomko Elena , Volynkina Natalya , Tonelli Claudio
Published: October 2002

The kinetics of the dibutyltin dilaurate (DBTDL)‐catalyzed urethane formation reactions of cyclohexyl isocyanate (CHI) with model monofunctional fluorinated alcohols and fluoropolyether diol Z‐DOL H‐1000 of various molecular weights (100–1084 g mol−1) in different solvents were studied. IR spectroscopy and chemical titration methods were used for measuring the rate of the total NCO disappearance at 30–60 °C. The effects of the reagents and DBTDL catalyst concentrations, the solvent and hydroxyl‐containing compound nature, and the temperature on the reaction rate and mechanism were investigated. Depending on the initial reagent concentration and solvent, the reactions could be well described by zero‐order, first‐order, second‐order, or more complex equations. The reaction mechanism, including the formation of intermediate ternary or binary complexes of reagents with the tin catalyst, could vary with the concentration and solvent and even during the reaction. The results were treated with a rate expression analogous to those used for enzymatic reactions. Under the explored conditions, the rate of the uncatalyzed reaction of fluorinated alcohols with CHI was negligible. Moreover, there was no allophanate formation, nor were there other side reactions, catalysis by urethane in the absence of DBTDL, or a synergetic effect in the presence of the tin catalyst. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 3771–3795, 2002
Synthesis and characterization of novel poly(vinyl chloride)‐based grafts: Poly(vinyl chloride‐co‐2‐chloropropene) fitted with multiple high‐glass‐transition‐temperature polyolefin branches
Authors: Pi Zhengjie , Kennedy Joseph P. , Summers James W.
Published: October 2002

The tertiary chlorine (Clt) content of vinyl chloride/2‐chloropropene copolymers [P(VC‐co‐2CP)] was determined by NMR spectroscopy. Copolymers containing 6.8–47.0 Clt's per P(VC‐co‐2CP) chain were used to initiate the cationic grafting of α‐methylstyrene, norbornadiene, indene, and norbornene with Et2AlCl under various conditions. Grafting was demonstrated by selective solvent extraction, and the effect of the experimental conditions on the grafting efficiency was examined. Select rheological and thermal characteristics of P(VC‐co‐2CP) grafts, including the glass‐transition temperature, heat deflection temperature, and discoloration upon heating, were studied. P(VC‐co‐2CP) carrying 7–11 poly(α‐methylstyrene) or polynorbornadiene branches per chain raised the glass‐transition temperature to, or above, that of a blend control. P(VC‐co‐2CP)s fitted with polyindene or polynorbornene branches were less effective in raising the mechanical properties. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 3644–3651, 2002
Radical telomerization of 1,3‐butadiene with perfluoroalkyl iodides in the presence of potassium carbonate
Authors: Lebreton Pierre , Ameduri Bruno , Boutevin Bernard , Cot Didier , Corpart Jean‐Marc
Published: October 2002

The radical telomerization of 1,3‐butadiene with perfluoroalkyl iodides (C6F13I or merely C8F17I) initiated by di‐tert‐butyl peroxide was studied in the presence of various amounts of potassium carbonate at 145 °C in acetonitrile. The influence of this salt on both the kinetics and the telomer characteristics (color, molar mass, and functionality) was established. First, the determination of the chain‐transfer constant of C8F17I led to a value (2.52) similar to that obtained under the same conditions without any K2CO3 (2.59). Second, 1,3‐butadiene conversion was much faster, and the molar mass/time profiles were also quite different, revealing the formation of high molar mass polymers at the end of conversion, which was not observed in previous studies without any K2CO3. Moreover, great improvements in the functionality of the fluorinated telomers were achieved (closer to unity). The products were also not as colored as before (black in the absence of K2CO3), and this allowed valuable application tests. With electronic microscopy, K2CO3 was shown to neutralize hydrogen iodide (HI) produced in the course of the reaction, which caused major drawbacks (e.g., low functionality and dark color). © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 3743–3756, 2002
Effect of the segmental mobility restriction on the thermoset chemical kinetics
Authors: Antonucci V. , Giordano M. , Nicolais L.
Published: October 2002

The cure kinetics of an epoxy–amine commercial thermoset system have been investigated with the isothermal differential scanning calorimetry technique. In particular, a kinetic study has been performed in the glass–transition zone, in which diffusion phenomena compete with the chemical transformations and the overall reaction rate is partially slowed by the reduced segmental chain mobility. A generalized form of the Vogel equation has been formulated to account for the effect of the increasing glass–transition temperature on the chain mobility and, therefore, on the overall reaction rate. The kinetic model has been expressed with two factors representing the chemical reaction rate and the segmental mobility reduction. As the main result, the activation energy relative to the diffusion phenomena has been found to be very low, having a value of 42.5 K ≈ 0.356 kJ/mol, which is compatible only with the small‐angle rotation of the reactive unit. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 3757–3770, 2002
Recurrent unilateral bacterial pneumonias and interstitial fibrosis associated with pulmonary vein atresia: Successful treatment with endovascular stent implantation
Authors: Sacco O. , Fregonese B. , Fregonese L. , Gambini C. , Pongiglione G. , Rossi G.A.
Published: October 2002

A variety of pulmonary vascular disorders, such as hemangiomatosis, telangectasia, and veno‐occlusive disease, may be involved in the pathogenesis of interstitial lung diseases. We describe the case of a girl with recurrent bacterial pneumonia and progressive interstitial fibrosis affecting the right lung. Morphologic evaluation of the lung biopsy showed structural changes of the vessel walls suggesting pulmonary hypertension. The echocardiogram showed the presence of centripetal blood flow in the right pulmonary artery from the periphery of the lung to the heart. A selective right angiography demonstrated the presence of pulmonary venous obstruction at the veno‐atrial junction, successfully treated by endovascular stent implantation during cardiac catheterization. Pediatr Pulmonol. 2002; 34:324–328. © 2002 Wiley‐Liss, Inc.
Gavaging the infant lung
Authors: Avital Avraham , Godfrey Simon , Bortz Raphael , Uwyyed Kamal , Springer Chaim
Published: October 2002

An 8‐month‐old female infant was hospitalized for persistent bilateral infiltrates, failure to thrive, and tachypnea. An extensive diagnostic workup was negative, except for strong oil‐red O staining of the white‐turbid bronchoalveolar lavage fluid and borderline esophageal pH monitoring. Conservative treatment failed, and she was scheduled for gastrostomy and Nissen‐fundoplication until the family physician found that the anxious mother was feeding the child forcibly, which caused chronic aspiration pneumonitis. The mother was given psychological support and was supervised, and the child recovered completely. Pediatr Pulmonol. 2002; 34:388–390. © 2002 Wiley‐Liss, Inc.