bluuebunny/crossref_metadata_2025 huggingface dataset:
Eye stalks or no eye stalks: A structural comparison of pupal development in the stalk‐eyed fly cyrtodiopsis and in drosophila
Authors: Buschbeck Elke K. , Roosevelt Jessica L. , Hoy Ronald R.
Published: August 2002

After emergence from the puparium, stalk‐eyed flies of the family Diopsidae rapidly expand their head capsule so that the eyes and optic lobes are displaced at the ends of stalks that extend from the central head. Because the expansion takes place in only 15 minutes, we are especially interested in ontogenetic modifications that may facilitate such a rapid and dramatic change. To examine the pupal development of the brain, we used Bodian staining in the stalk‐eyed fly, Cyrtodiopsis whitei and compared it with development in the fruit fly, Drosophila melanogaster, which serves as a “typical” dipteran example without eye stalks. Early in pupal development, the neuropil organization of the two species is fairly similar. In both species, columns are present in the outer medulla and giant fibers are discernible in the lobula plate. In contrast to D. melanogaster, C. whitei shows a small, neck‐like constriction between the optic lobes and the rest of the brain. By 20% of pupal development, the divergence is more apparent, and by 30%, the future eye stalk and optic nerve of C. whitei has started to form. During the remaining 70% of development, the initially thick optic nerve narrows, and becomes gradually elongated, eventually coiling and folding throughout the short eye stalk. Similarly, the cuticle of the surrounding region becomes constricted, slightly elongated, and gradually appears more and more densely corrugated, like an accordion bellows. However, except for the formation of the optic nerve, the dense aggregation of cuticle around it, and a shift in orientation of the neuropils, the developmental programs of the two species are remarkably similar. This suggests that only a few aspects of development have been modified during the course of evolution to generate the stalk‐eyed phenotype. At eclosion, the imago of C. whitei goes through a pumping process to inflate the eye stalks to their full length. Measurements of the diameter of the optic nerve before and after the expansion reveal only a small decrease. We propose that the cuticular folding of the eye stalk as well as the coiling of the optic nerve prepare the pupa well for the rapid and dramatic eye‐stalk inflation after eclosion. J. Comp. Neurol. 433:486–498, 2001. © 2001 Wiley‐Liss, Inc.
Comparison of sensory and sympathetic innervation of the dura mater and posterior longitudinal ligament in the cervical spine after removal of the stellate ganglion
Authors: Yamada Hitoshi , Honda Takashi , Yaginuma Hiroyuki , Kikuchi Shinichi , Sugiura Yasuo
Published: August 2002

Although cervical spinal tissues are rich in sensory and sympathetic fibers, which play a significant role in clinical phenomena, there is little information available regarding their anatomical characteristics. In this study, we compared the innervation of the cervical dura mater and the posterior longitudinal ligament (PLL) to that after removal of the stellate ganglion to determine whether the anatomical background plays a significant role in clinical manifestations. Immunoreactivities for calcitonin gene‐related peptide (CGRP) and substance P (SP) were used as sensory markers, and immunoreactivity for neuropeptide Y (NPY) was used as a sympathetic marker. Sensory fibers in the cervical dura mater were distributed within each cervical segment, but those in the PLL extended beyond the segmental borders. A dense sensory fiber network forming a single layer was seen at the intervertebral disc region in the cervical PLL, whereas sympathetic fibers in this region were sparsely distributed. Sympathetic fibers were distributed not only around the vascular wall but also in the region independent from vessels, and some occasionally ran together with sensory fibers in both the dura mater and the PLL. Removal of the stellate ganglion had little effect on the distribution of sensory fibers but denervated the sympathetic fiber networks in the region independent from vessels of the upper ipsilateral cervical PLL. In conclusion, the cervical dura mater and the PLL have different sensory and sympathetic innervations. Sympathetic fibers pass through the stellate ganglion to project to the region independent from vessels in the upper cervical PLL. Clinical symptoms may be attributed to this characteristic innervation of the cervical spine. J. Comp. Neurol. 434:86–100, 2001. © 2001 Wiley‐Liss, Inc.
Early efferent innervation of the zebrafish lateral line
Authors: Bricaud Olivier , Chaar Vicky , Dambly‐Chaudière Christine , Ghysen Alain
Published: August 2002

We examined the efferent innervation of the lateral line in zebrafish larvae. Three efferent nuclei were previously reported for the posterior line, two in the hindbrain and one in the ventral hypothalamus. Here we show that the same three nuclei innervate the anterior line as well. The rhombencephalic neurons innervate either the anterior or the posterior line. The diencephalic neurons seem to innervate both lines as well as the ear. The diencephalic efferents are labeled by anti‐tyrosine hydroxylase antibodies and probably use dopamine as a transmitter. They are among the very first catecholaminergic neurons to differentiate in the brain and extend branches into the lateral line system almost as soon as the latter forms. We discuss possible functions of the rhombencephalic and diencephalic efferents. J. Comp. Neurol. 434:253–261, 2001. © 2001 Wiley‐Liss, Inc.
Synaptic patterns of thalamocortical afferents in mouse barrels at postnatal day 11
Authors: Lev Dmitri L. , Weinfeld Elizabeth , White Edward L.
Published: August 2002

This study focuses on the synaptic output patterns of thalamocortical axons in mouse barrel cortex at postnatal day (P) 11. Axons were labeled by biotinylated dextran amine transported anterogradely following injection in vivo into the ventrobasal thalamus. Labeled axons in the posteromedial barrel subfield were examined by light and electron microscopy and then reconstructed in three dimensions to assess the spatial distribution of their synapses. Thalamocortical axons form asymmetrical synapses, both at varicosities and along cylindrical portions of the axons; usually, only one synapse occurs per site, contrasting with the case in the adult, in which multiple synapses are typical. At P11, varicosities without synapses are common. As in adult barrels, approximately 80% of synapses formed by thalamocortical axons are with dendritic spines; 20% are with dendritic shafts. The similarity in the distribution of thalamocortical synapses onto spines vs. dendrites in developing and mature barrels indicates that adult synaptic patterns already are specified at a very early stage of thalamocortical synaptogenesis. J. Comp. Neurol. 442:63–77, 2002. ©2002 Wiley‐Liss, Inc.
Enkephalinergic control of the secretory activity of neurons producing stereoisomers of crustacean hyperglycemic hormone in the eyestalk of the crayfish Orconectes limosus
Authors: Ollivaux Céline , Dircksen Heinrich , Toullec Jean‐Yves , Soyez Daniel
Published: August 2002

A subgroup of neurons in the classical X‐organ‐sinus gland neuroendocrine system of the crayfish (Orconectes limosus) eyestalk produces two chiral forms of the crustacean hyperglycemic hormone (CHH) in two different types of neurons: CHH in ∼22 cells and D‐Phe3 CHH in eight cells. Previous reports have demonstrated that release of CHH from the sinus gland is inhibited by enkephalins. Here, we have addressed the questions of 1) whether this inhibition affects one or both types of CHH neurons, 2) where the site of enkephalinergic control of CHH and/or D‐Phe3 CHH is, and 3) whether the inhibitory effect is due to direct or indirect interactions of enkephalinergic neurons with CHH cells. In vitro incubations of neurosecretory complexes followed by immunoassays of CHH isoforms indicated that both methionine‐ and leucine‐enkephalins inhibit release of the two CHH isoforms from crayfish eyestalks, by a receptor‐mediated process. Whole‐mount double‐ or triple‐immunofluorescence labelings combined with confocal microscopy revealed enkephalin immunostaining in all neuropils of the eyestalk, except in the sinus gland. Virtual thin confocal sections showed many close appositions between terminals of enkephalinergic neurons and dendritic arborizations of specific CHH‐immunoreactive cells in the medulla terminalis neuropil. This provides the first evidence for direct inputs from enkephalinergic neurons into dendrites of both CHH cell types, which suggests that enkephalins inhibit release of both CHH isoforms via synaptic contacts. J. Comp. Neurol. 444:1–9, 2002. © 2002 Wiley‐Liss, Inc.
Comparison of three second‐order accurate reconstruction schemes for 2D Euler and Navier–Stokes compressible flows on unstructured grids
Authors: Marques N. P. C. , Pereira J. C. F.
Published: August 2002

This paper reports an intercomparison of three second‐order accurate reconstruction schemes to predict 2D steady‐state compressible Euler and Navier–Stokes flows on unstructured meshes. The schemes comprise one monotone slope limiter (Barth and Jespersen, A1AA Paper 89‐0366, 1989) and two approximately monotone methods: the slope limiter due to Venkatakrishnan and a data‐dependent weighting least‐squares procedure (Gooch, Journal of Computational Physics, 1997; 133:6–17). In addition to the 1D scalar wave problem, comparisons were performed under two inviscid test cases: a supersonic 10° ramp and a supersonic bump; and two viscous laminar compressible flow cases: the Blasius boundary layer and a double‐throated nozzle. The data‐dependent oscillatory behaviour is found to be dependent on a user‐supplied constant. The three schemes are compared in terms of accuracy and computational efficiency. The results show that the data‐dependent procedure always returns a numerical steady‐state solution, more accurate than the ones returned by the slope limiters. Its use for Navier–Stokes flow calculations is recommended. Copyright © 2001 John Wiley & Sons, Ltd.
On the discretization of problems involving periodic planar tilings
Authors: Bénard André , Diaz Alejandro R.
Published: August 2002

Features related to the discretization of problems characterized by simple periodic tilings using cells of various shapes are discussed. Various cell geometries that tile the plane periodically are considered. Equivalent problems are identified, where the discretization can take place on a parallelogram, regardless of the shape of the original cell. These equivalent problems also suggest a numbering of the equations that results in matrices with interesting and useful properties. Copyright © 2001 John Wiley & Sons, Ltd.
Numerical simulation of transient free surface flow with moving contact lines
Authors: Powell C. A. , Savage M. D.
Published: August 2002

A Lagrangian finite element algorithm is described for solving two‐dimensional, time‐dependent free surface flows, in which moving contact lines are simulated by allowing local slip and the use of a ‘Tanner Law’. The method is implemented using structured meshes, which are locally refined in the contact line regions, and periodic remeshing to control element distortion. The benchmark problem of capillary motion between parallel horizontal plates is solved to illustrate the accuracy of the method and its applicability to flows of engineering relevance. Copyright © 2001 John Wiley & Sons, Ltd.
Identification of evolutionary sequential systems—part 2: genetic simulation experiments
Authors: Baron Claude , Geffroy Jean‐Claude , Zamilpa César
Published: August 2002

In a preceding paper we have presented a unified view of the identification methods dedicated to adaptive sequential systems. In this paper, we develop the resolution technique based on genetic simulation. We analyse the various parameters of such an approach, then, we propose a tool intended to demonstrate the interest of this new approach, and finally we present some differential identification experiments conducted with this tool. Copyright © 2001 John Wiley & Sons, Ltd.
Adaptive data refinement in the spectral stochastic finite element method
Authors: Ghanem R. , Pellissetti M.
Published: August 2002

One version of the stochastic finite element method involves representing the solution with respect to a basis in the space of random variables and evaluating the co‐ordinates of the solution with respect to this basis by relying on Hilbert space projections. The approach results in an explicit dependence of the solution on certain statistics of the data. The error in evaluating these statistics, which is directly related to the amount of available data, can be propagated into errors in computing probabilistic measures of the solution. This provides the possibility of controlling the approximation error, due to limitations in the data, in probabilistic statements regarding the performance of the system under consideration. In addition to this error associated with data resolution, is added the more traditional error, associated with mesh resolution. This latter also contributes to polluting the estimated probabilities associated with the problem. The present paper will develop the above concepts and indicate how they can be coupled in order to yield a more meaningful and useful measure of approximation error in a given problem. Copyright © 2002 John Wiley & Sons, Ltd.
Finite and infinite elements for a simple problem in quantum mechanics
Authors: Bettess Peter , Abram Richard A.
Published: August 2002

Finite element and infinite element models are used to predict the behaviour of a simple example problem in quantum mechanics, that of a linear harmonic oscillator. It is shown that good agreement with the analytical solution is obtained and that the infinite elements give a significant improvement in accuracy at virtually no cost. It is concluded that finite and infinite elements models are a promising method for quantum mechanics problems. Copyright © 2002 John Wiley & Sons, Ltd.
A Quantization Property for Moving Line Vortices
Authors: Lin Fang‐Hua , Rivière Tristan
Published: August 2002

We prove that if the energy of a time‐evolving three‐dimensional Ginzburg‐Landau configuration is small enough on a given parabolic ball, then no line vortex passes through the ball of half‐radius. © 2001 John Wiley & Sons, Inc.
Algorithmic support for model transformation in object‐oriented software development
Authors: Schönberger Siegfried , Keller Rudolf K. , Khriss Ismail
Published: August 2002

Current methods for object‐oriented software development provide notation for the specification of models, yet do not sufficiently relate the different model types to each other, nor do they provide support for transformations from one model type to another. This makes transformations a manual activity, which increases the risk of inconsistencies among models and may lead to a loss of information. We have developed and implemented an algorithm supporting one of the transitions from analysis to design, the transformation of scenario models into behavior models. This algorithm supports the Unified Modelling Language (UML), mapping the UML's collaboration diagrams into state transition diagrams. We believe that CASE tools implementing such algorithms will be highly beneficial in object‐oriented software development. In this paper, we provide an overview of our algorithm and discuss all its major steps. The algorithm is detailed in semi‐formal English and illustrated with a number of examples. Furthermore, the algorithm is assessed from different perspectives, such as scope and role in the overall development process, issues in the design of the algorithm, complexity, implementation and experimentation, and related work. Copyright © 2001 John Wiley & Sons, Ltd.
Does expressed emotion predict behaviour therapy outcome at follow‐up for obsessive‐compulsive disorder and agoraphobia?
Authors: Steketee Gail , Chambless Dianne L.
Published: August 2002

The relationship of expressed emotion (EE) to outcome of behaviour therapy at 1‐year follow‐up was examined in a sample of patients with obsessive‐compulsive disorder (OCD) or panic disorder with agoraphobia (PDA). Included were 54 subjects who were reliably changed after outpatient treatment via in vivo exposure (plus response prevention for OCD). Perhaps because few clients relapsed (11%), EE variables assessed by the Camberwell Family Interview and perceived criticism ratings, although successful in predicting drop‐out and posttest outcome in this sample, were not significantly related to regression during the follow‐up period. The sole exception, critical comments from the CFI, predicted worsened social adjustment at follow‐up, but only for PDA patients. The experience of stressful life events did not interact with EE variables to predict outcome. Copyright © 2001 John Wiley & Sons, Ltd.
A‐map representations and asymptotically almost periodic responses
Authors: Sandberg Irwin W.
Published: August 2002

It was recently shown that for each member G of a large class of causal time‐invariant non‐linear input–output maps, with inputs and outputs defined on the non‐negative integers, there is a functional A on the input set such that (Gs) (k) has the representation A(Fks) for all k and each input s, in which Fk is a simple linear map that does not depend on G. In this paper, we consider non‐linear maps G that have such ‘A‐map representations’. We observe that these Gs have extensions to a domain of inputs defined on the set of all integers. We show that these extensions possess some interesting properties including a certain important uniqueness property. As an application, we show that under the (very often satisfied) conditions of time invariance, causality, and approximately finite memory, and under typically mild boundedness and continuity conditions, the response of G to a discrete‐time asymptotically almost periodic input is an output that is always an asymptotically almost periodic function, and that the almost periodic part of the output is independent of the transient part of the input. We also give corresponding results for a continuous‐time case. Copyright © 2001 John Wiley & Sons, Ltd.
Z+fading memory and extensions of input–output maps
Authors: Sandberg Irwin W.
Published: August 2002

An Erratum for this article has been published in theInternational Journal of Circuit Theory and Applications 30(4) 2002, 179.

Much is known about time‐invariant non‐linear systems with inputs and outputs defined onZ+that possess approximately‐finite memory. For example, under mild additional conditions, they can be approximated arbitrarily well by the maps of certain interesting simple structures. An important fact that gives meaning to results concerning such systems is that the approximately‐finite‐memory condition is known to be often met. Here we consider the known proposition that if a causal time‐invariant discrete‐time input–output mapHhas fading memory on a set of bounded functions defined on all of the integersZ, thenHcan be approximated arbitrarily well by a finite Volterra series operator. We show that in a certain sense, involving the existence of extensions of system maps, this result too has wide applicability. Copyright © 2001 John Wiley & Sons, Ltd.
Small‐signal analysis of interleaved dual boost converter
Authors: Veerachary Mummadi , Senjyu Tomonobu , Uezato Katsumi
Published: August 2002

This paper presents a systematic development of steady‐state, small‐signal models of interleaved dual boost converter operating in a continuous current mode. These models are derived by employing the well‐known signal flow graph method. This signal flow graph approach provides a means to directly translate the switching converter into its equivalent graphic model, from which a complete behaviour of the converter can easily be studied. Steady‐state performance, small‐signal characteristic transfer functions are derived using Mason's gain formula. The bode plots of audiosusceptibility, input impedance, output impedance, and control‐to‐output transfer functions are determined and illustrated using MATLAB for different values of load resistances, duty ratios. Small‐signal frequency responses obtained from the signal flow graph method are validated with PSPICE simulator results. To validate the signal flow graph modelling equations, sample steady‐state experimental results are provided. Copyright © 2001 John Wiley & Sons, Ltd.
Human immunodeficiency virus envelope‐dependent cell‐cell fusion: A quantitative fluorescence cytometric assay
Authors: Huerta Leonor , Lamoyi Edmundo , Báez‐Saldaña Armida , Larralde Carlos
Published: August 2002

Background

In vitro fusion of transfected cells expressing the human immunodeficiency virus (HIV) envelope proteins gp120/gp41, with target cells expressing CD4, and a suitable chemokine coreceptor is used widely to investigate the mechanisms of molecular recognition and membrane fusion involved in the entry of the HIV genome into cells and in syncytia formation.

Methods

We developed an assay that uses two different fluorescent lipophilic probes to single label each reacting cell population and flow cytometry to quantify the extent of cellular fusion after coculture.

Results

Fused cells are detected as double‐fluorescent particles in this assay, therefore permitting measurement of their proportion in the total cell population. The time course and extent of HIV‐glycoprotein–related cellular fusion, the optimal cell ratio, the size and cell composition of the fusion products, and the inhibition of fusion caused by soluble CD4 and anti‐CXCR4 antibody 12G5 were determined. The assay was applied to measure fusion between gp120/gp41 and CD4‐expressing cells growing as monolayers (HeLa/CHO fusion), as well as to suspension lymphocyte cultures (Jurkat/Jurkat fusion).

Conclusions

The method's simple technical and minimal cell‐invasive procedures, as well as its non‐ambiguous automatic numerical quantification should be useful for the study of factors influencing cell‐cell fusion. Cytometry 47:100–106, 2002. © 2002 Wiley‐Liss, Inc.
Detection of localized caspase activity in early apoptotic cells by laser scanning cytometry
Authors: Telford William G. , Komoriya Akira , Packard Beverly Z.
Published: August 2002

Background

Caspase activation is a critical early step in the onset of apoptosis. Cell‐permeable fluorogenic caspase substrates have proven valuable in detecting caspase activation by flow cytometry. Nevertheless, detection of early low‐level caspase activation has been difficult using conventional area or peak fluorescence analysis by flow cytometry, despite the apparent presence of these cells as observed by microscopy. We describe a method utilizing maximum fluorescence pixel analysis by laser scanning cytometry (LSC) to detect early apoptotic cells.

Methods

The PhiPhiLux‐G1D2 caspase 3/7 substrate was used in combination with DNA dye exclusion and annexin V binding to identify several stages of apoptosis in EL4 murine thymoma cells by both traditional flow and LSC. LSC analysis of maximum pixel brightness in individual cells demonstrated an intermediate caspase‐low subpopulation not detectable by flow or LSC integral analysis. LSC analysis of caspase activity was then carried out using the larger UMR‐106 rat osteosarcoma cell line to determine if this apparent early caspase activity could be correlated with localized, punctate caspase activity observed by microscopy.

Results

The caspase‐low subpopulation found in apoptotic EL4 cells was also observable in UMR‐106 cells. Relocation to cells with low fluorescence due to caspase activity and subsequent examination by microscopy demonstrated that these latter cells indeed show punctate, highly localized caspase activation foci that might represent an early stage in caspase activation.

Conclusions

Cells with low‐level, localized caspase expression can be detected using maximum pixel analysis by LSC. This methodology allows an early step of apoptotic activation to be resolved for further analysis. Cytometry 47:81–88, 2002. © 2002 Wiley‐Liss, Inc.
Preoperative prediction of postoperative edema and effusion in pediatric cardiac surgery by altered antigen expression patterns on granulocytes and monocytes
Authors: Tárnok Attila , Bocsi József , Pipek Michal , Osmancik Pavel , Valet Günter , Schneider Peter , Hambsch Jörg
Published: August 2002

Postoperative edema and effusion (POEE) following cardiopulmonary bypass (CPB) surgery in children retards recovery and may aggravate postpericardiotomy (PPS), capillary leak syndrome (CLS), or multiorgan failure (MOF). Compared with complication‐free children, POEE affected children have different preoperative serum levels of circulating cytokines and adhesion molecules. These levels may be used preoperatively to assess POEE, but their determination is time consuming, costly, and a substantial blood volume is required. Altered serum levels of cytokines and adhesion molecules also may be reflected in altered antigen expression on circulating blood leukocytes. The predictive potential of flow cytometric (FCM) leukocyte immunophenotyping was explored as a sensitive and fast method that required small blood samples. Blood samples taken 24 h preoperatively from 49 patients (3–18 years old) were stained with monoclonal antibodies for adhesion molecules (ICAM‐1, LFA‐1, Mac‐1) or constitutive/activation markers (CD4, CD14, CD16, CD25, CD54, CD69, HLA‐DR) and measured on a microbead calibrated FCM. Neutrophils, monocytes, and eosinophils from POEE patients express higher preoperative levels of LFA‐1, monocytes, HLA‐DR, and other activation markers (all P < 0.03). Over 89% of the patients were classified correctly by using two discriminant analysis methods (sensitivity, >76%; specificity, >86%; positive prediction, >80%; negative prediction, >83%). Granulocytes and monocytes of postoperative POEE patients exhibit significant preoperative immune activation, suggesting an increased risk for patients with atopic/allergic predisposition. Surgical trauma and CPB cause additional immune activation, leading to POEE by a summative response. Most patients at risk for POEE can be identified preoperatively by using data pattern analysis on FCM‐derived parameters. Cytometry (Comm. Clin. Cytometry) 46:247–253, 2001. © 2001 Wiley‐Liss, Inc.
Enumeration of CD34+ cells in cord blood: A variation on a single‐platform flow cytometric method based on the ISHAGE gating strategy
Authors: Brocklebank Anne M. , Sparrow Rosemary L.
Published: August 2002

Single‐platform flow cytometric absolute cell counting protocols provide increased robustness for CD34+ cell enumeration by limiting potential sources of imprecision. However, samples with any cellular fragmentation or debris, such as cord blood samples, provide challenges for these assays. We describe a simple, robust absolute CD34+ cell counting protocol, suitable for cord blood, using TRUCOUNT™ absolute count tubes (BD Biosciences, San Jose, CA) and a modified ISHAGE (International Society for Hematotherapy and Graft Engineering) gating strategy. An advantage of TRUCOUNT tubes is that each tube is supplied with a known number of lyophilized fluorescent beads. The method includes no‐wash fixative‐free ammonium chloride red blood cell lysis and the viability dye, 7‐amino actinomycin D, to exclude dead cells. The threshold was set on CD45 expression in the FL1 channel and an exclusion gate in the forward scatter channel reduced debris. No manual adjustment of the gating regions was required, even for samples in less than optimal condition. Comparison of the TRUCOUNT‐ISHAGE protocol with the original dual‐platform ISHAGE assay (n = 30) and the single‐platform ISHAGE protocol using Flow‐Count™ Fluorospheres (Beckman Coulter, Fullerton, CA; n = 22) showed high correlation (R2 = 0.949 and 0.989, respectively) and no significant difference or bias for samples ranging from 22 to 600 CD34+ cells per microliter. Results are presented that demonstrate the detrimental effect of a fixative‐containing lysis reagent when used in a lyse‐and‐wash procedure. The TRUCOUNT‐ISHAGE protocol combines the attributes of TRUCOUNT tubes and the ISHAGE gating strategy to provide a single‐platform protocol capable of achieving readily standardization of CD34+ cell enumeration. Cytometry (Comm. Clin. Cytometry) 46:254–261, 2001. © 2001 Wiley‐Liss, Inc.
Simulation and analysis of Awerbuch–Peleg and GSM schemes for location tracking of mobile users
Authors: Weerakoon Ishan P. , Sidhu Deepinder P.
Published: August 2002

Mobile users are increasingly demanding full access to networked communications while they are on the move. Several studies have shown that the overhead incurred by the network to keep track of the current location of mobile users is considerably high. The methods currently used for location tracking incur heavy unnecessary costs by requiring that users update locations in their home networks after each move regardless of the distance at which the move occurs, and that all search attempts for a mobile user are first routed to that user's home network. The Awerbuch–Peleg scheme presents a formal model for location tracking which attempts to minimize the cost of local operations—both move and find operations—through the construction of a regional hierarchy. In this paper we present a performance evaluation of the Awerbuch–Peleg scheme. We also compare its performance to that of the GSM‐based location tracking scheme. It is found that the Awerbuch–Peleg scheme in general results in higher costs than the GSM scheme. The reason for this is found to be some unexpected properties of the read and write sets which are key components of the Awerbuch–Peleg scheme. Copyright © 2001 John Wiley & Sons, Ltd.
A method of accurate determination of azimuthal distribution of received RF power
Authors: Alexandridis A. A. , Dangakis K. , Kostarakis P. , Lazarakis F.
Published: August 2002

In this paper, we introduce a method for the determination of directional distribution of received RF power, with angular resolution independent of receiving antenna radiation pattern. The proposed method is based on a series of measurements taken while rotating, at fixed predefined steps, a usual directional antenna of known radiation pattern on the azimuthal plain. It is proved that the resolution accuracy of the measurement method depends only on the angular step of the antenna rotation and it is independent of the antenna beamwidth. As a result of this feature, the proposed method allows the determination of the RF power angular distribution with fine resolution using a directional antenna of much wider beamwidth for the measurements. Copyright © 2001 John Wiley & Sons, Ltd.
Modem‐based communications using synchronized chaos
Authors: Carrasco R. , Pointon C.
Published: August 2002

This paper considers the use of chaotic dynamics to enhance or add value to telecommunications systems. An application in the form of secure communications, with particular emphasis on mobile radio systems is investigated. Standard continuous time descriptions of the Lorenz and Chua chaotic attractors are transformed into the discrete time domain and used in the design of a secure chaotic modem which includes the digital modulation schemes: quadrature phase shift keying (QPSK) and π/4‐QPSK with square‐root raised cosine pulse shaping filters. The results of analytical computer simulations show that the performance of both modem systems over limited bandwidth additive white Gaussian noise (AWGN), and Rayleigh and Rician fading channels induces no degradation in the bit error probability. Finally, in order to demonstrate that the chaotic modem offers a degree of robustness to eavesdropping, a reconstruction model is derived and applied to the communication scheme. It is shown that, due to inaccurate information surrounding the state of the system, a reconstruction of the system was not possible. Copyright © 2001 John Wiley & Sons, Ltd.
Myofibroblastoma of the male breast: A diagnostic problem on fine‐needle aspiration cytology
Authors: Powari Manish , Srinivasan Radhika , Radotra Bishan D.
Published: August 2002

Myofibroblastoma is an uncommon neoplasm of the male breast. Herein, we describe the cytologic features seen in the fine‐needle aspirate of a 45‐year‐old man. The smears were cellular with intimate association of tumor cells with extracellular matrix material. The cells were spindle to polygonal and were without significant atypia. Numerous mast cells were observed. Nuclear grooving was present only occasionally, although this was conspicuous histologically. The presence of hyaline bands in between tumor cells, another interesting feature, was appreciated retrospectively. This neoplasm was initially misinterpreted as a malignant soft tissue tumor. Awareness of the cytologic features coupled with mammography should prevent a misdiagnosis of this tumor. Diagn. Cytopathol. 2002;26:290–293. © 2002 Wiley‐Liss, Inc.
Aspiration cytodiagnosis of amyloid from vitreous fluid
Authors: Gupta Raj K. , Wakefield John , Halliwell T. , Foo K. , Lallu Sharda , Naran Sarla , Fauck Robert
Published: August 2002

Amyloidosis of the vitreous body is a rare disorder that causes progressive visual loss. In this report, a 36‐yr‐old female with familial amyloidosis is described in whom a progressive reduction of vision in both eyes over the last 4 yr was ascribed to vitreous opacities due to amyloid. A left pars plana vitrectomy was performed and an aspirated sample of the vitreous on cytologic examination showed vitreous strands admixed with abundant dense, pink, globular material which was intensely positive on Congo red staining and exhibited yellowish‐green birefringence indicative of amyloid. This was further confirmed ultrastructurally, which showed the classical appearance of amyloid fibrils. The case is of interest not only in view of the rarity of the condition but also in view of the fact that as far as we are aware the cytodiagnosis of amyloid from an aspirate sample from the vitreous has not been previously described in the literature. Diagn. Cytopathol. 2002;26:294–296. © 2002 Wiley‐Liss, Inc.
Diagnosis of melanoma aspirates on ThinPrep®: The University of Michigan experience
Authors: Barkan Güliz Akdas , Rubin Mark A. , Michael Claire W.
Published: August 2002

The purpose of this study was to compare the cytologic features of melanoma fine‐needle aspirates (FNAs) prepared by ThinPrep® (TP) with those in conventional smears (CS) and to identify any diagnostic pitfalls. Fifty‐one aspirates diagnosed as melanoma were obtained, 36 of which were prepared by both TP and CS. The preparations were evaluated for cellularity, cell aggregates, cellular appearance, melanin pigment, cytoplasmic, and nuclear features. Categorical data were analyzed by the chi‐square test and continuous data by the Wilcoxin‐signed rank test. Correlation was determined by Spearman's test for bivariate correlations (rho). Good correlation between the two methods was identified for the following features: cellularity, cell type, bi/multinucleated cells, cytoplasmic features, NC ratio, and presence of macronucleoli. TP exhibits coarser chromatin compared to CS (P = 0.005). Six of 36 CS contained large cellular groups; none of the TP contained them (P = 0.018). Twenty‐five of 36 CS contained intranuclear inclusions as opposed to 12/36 TP (P < 0.001). The number of inclusions was significantly reduced on TP. The amount of intracellular melanin was the same with both techniques. Background melanin was markedly reduced on TP except when either trapped by fibrin or attached to cellular clusters (P = 0.006). Background blood was also markedly reduced on TP (P < 0.005). In summary, the cytological features of TP and CS for FNA evaluation of melanoma correlate well; however, one needs to be aware of the cytologic alterations introduced by TP. TP is a sufficient preparation method in the diagnosis of melanoma FNA aspirates when performed by clinicians. It is also a useful adjunct in bloody or low‐cellular aspirates, where it tends to reduce the background blood and concentrate the cells. Diagn. Cytopathol. 2002;26:334–339. © 2002 Wiley‐Liss, Inc.
Adenocarcinoma in colonic brushing cytology: High‐grade dysplasia as a diagnostic pitfall
Authors: Yu Gordon H. , Nayar Ritu , Furth Emma E.
Published: August 2002

Cytologic evaluation of brushing specimens obtained from the colon may be useful in the diagnosis of neoplastic and inflammatory lesions, as previous studies have reported favorable sensitivity and specificity figures for this procedure. In this study, we report our experience with 80 colonic brushings examined over a 5‐yr period. Thirty cases received an atypical or malignant cytologic diagnosis. Nineteen of 20 cases diagnosed cytologically as adenocarcinoma revealed adenocarcinoma on biopsy; one case showed only adenomatous epithelium on biopsy and subsequent resection. Cases diagnosed cytologically as “atypical” or “adenomatous” showed adenocarcinoma, adenoma, and inflammatory conditions upon biopsy.

Slides from 30 atypical/malignant cases were retrospectively reviewed for a number of cytomorphologic features and were correlated with the histologic diagnosis. Cases from histologically confirmed adenocarcinoma tended to show greater degrees of altered nuclear polarity, nuclear pleomorphism, membrane irregularities, and chromatin pattern alterations than those from histologically proven adenomatous or inflammatory lesions. The most likely cause of a false‐positive diagnosis in this setting is sampling of an adenoma with high‐grade dysplasia which fails to meet histologic criteria for adenocarcinoma (invasion of the underlying muscularis mucosae). Thus, in the second part of the study, we examined histologic sections from surgically excised adenomas to determine the frequency with which profound nuclear atypia is at least focally present, potentially resulting in a false‐positive cytology diagnosis upon brushing. Slides from 51 cases were reviewed; cytologic atypia beyond that typically observed in adenomas was not observed in 43% of cases. However, profound nuclear atypia was present in 6% of cases; cytologic evaluation of a brushing specimen from these lesions may have resulted in a false‐positive diagnosis of adenocarcinoma, despite the histologic diagnosis of adenoma with severe dysplasia. The remaining cases demonstrated intermediate degrees of atypia. These findings serve to quantitate the frequency with which cytohistologic discrepancies might be expected for mass lesions of the colon. Diagn. Cytopathol. 24:364–368, 2001. © 2001 Wiley‐Liss, Inc.
Absence of SV‐40 large T antigen (Tag) in malignant mesothelioma effusions: An immunocytochemical study
Authors: Simsir Aylin , Fetsch Patricia , Bedrossian Carlos W.M. , Ioffe Olga B. , Abati Andrea
Published: August 2002

Simian Virus 40 (SV 40) was recently implicated in the pathogenesis of malignant mesothelioma. The oncogenic capacity of SV‐40 is a function of a nuclear protein, the large T antigen (Tag). SV‐40 Tag DNA sequences are detected by the polymerase chain reaction in 40–80% of malignant mesothelial proliferations. However, the role of immunohistochemistry (IHC) in demonstrating the nuclear localization of Tag is controversial. We sought to determine the clinical utility of SV‐40 Tag IHC in pleural effusion cytology as an ancillary tool in the cytologic diagnosis of malignant mesothelioma (MM). Formalin‐fixed, paraffin‐embedded cell block sections from 100 pleural effusions (32 MMs, 25 benign reactive, 43 metastatic adenocarcinomas) were immunostained for the SV‐40 anti‐Tag, using two primary monoclonal SV‐40 Tag antibodies: clone Pab 416 and clone Pab 101. Despite strong and consistent immunoreactivity in positive controls, no nuclear immunostaining was observed in any case. We believe the small sample size in cytology cell block sections, the low viral copy number in infected cells, and the effect of formalin fixation may have resulted in absence of immunoreactivity. The role of SV‐40 Tag IHC in diagnostic cytopathology remains unclear unless further studies reliably show its detection. Diagn. Cytopathol. 25:203–207, 2001. © 2001 Wiley‐Liss, Inc.
Lobular carcinoma with cytoplasmic granules
Authors: Vdovenko Alexandre , Bass Randall , Tauchi‐Nishi Pamela , Namiki Thomas
Published: August 2002

We report on a case of invasive lobular carcinoma of the breast with a previously undescribed cytologic feature. Diff‐Quik‐stained cytologic preparations showed uniform single cells with prominent coarse cytoplasmic granules. Ultrastructurally, the granules showed features suggestive of autophagosomes and/or degenerative mitochondria. The cytologic differential diagnosis included granulocytic sarcoma, metastatic melanoma, extramedullary hematopoiesis, large granulocytic leukemia/lymphoma, and mast‐cell tumor. Adjunctive studies were helpful in the diagnosis of carcinoma. Histologic study of the mastectomy specimen showed classic type of invasive lobular carcinoma. Diagn. Cytopathol. 25:253–257, 2001. © 2001 Wiley‐Liss, Inc.
Specialized preparative devices are not needed for liquid‐based, thin‐layer cytology: An alternate manual method using a metastable alcoholic gel
Authors: Maksem John A. , Weidmann James
Published: August 2002

The blending and use of a metastable alcoholic gel is described. The gel creates durable, uniform suspensions of cells and small aggregates of cells. It allows the random, uniform transfer of virtually any liquid‐fixed cytology specimens to a glass slide without the use of specialized devices, proprietary disposables, or adhesive‐coated glass slides. The method is inexpensive and can be performed in a timely fashion, not impacting laboratory turnaround times or requiring the specimen to be processed by other laboratories. It empowers cytology laboratories of any size or level of complexity to make slides from readily available commercial cytology fixatives. It allows the total contents of liquid‐based cytology specimen vials to be examined, providing a “cytological method” for quality assuring liquid‐based cytology samples. Diagn. Cytopathol. 25:262–264, 2001. © 2001 Wiley‐Liss, Inc.
Metastatic metaplastic carcinoma of the breast (MCB): An uncharacteristic pattern of presentation with clinicopathologic correlation
Authors: Catroppo James F. , Lara Jonathan F.
Published: August 2002

Metaplastic carcinoma of the breast (MCB) is a well recognized but uncommon aberrant manifestation of poorly differentiated invasive carcinoma containing both epithelial (ductal) and mesenchymal elements as well as a transitional form between them. This heterogeneous tumor characteristically contains ductal carcinoma cells mixed with areas of diverse morphologic phenotype displaying spindle, squamous, chondroid, or osseous differentiation. Some studies have suggested that certain types of metaplastic carcinoma have a more favorable prognosis as compared with others. We describe a case involving a 67‐yr‐old woman who presented with metastatic nodules in the lungs and a vague but recent history of breast cancer. The case highlights a subtype of MCB with a predominant spindle cell component metastatic to the lung. Fine‐needle aspiration biopsy (FNAB) smears of the nodules revealed a bland, spindle cell, mesenchymal proliferation with minimal evidence of an epithelial component. A second primary was clinically excluded and a request for review of the original slides identified a metaplastic component to the original tumor with a histologic and immunohistochemical profile identical to the metastatic tumor, confirming origin from the breast. Metaplastic carcinomas of the breast commonly bypass axillary lymph nodes and present as distant metastases. FNAB diagnosis of metaplastic carcinoma of the breast is quite difficult at the primary site and poses a formidable diagnostic challenge at a metastatic site, especially when the dominant pattern is not of the usual type. The literature is reviewed, confirming the rarity of such a presentation and the novelty of this case. Confirmation by FNAB is also quite difficult but may become more commonplace as a trend toward minimal intervention continues to gain popularity. This case emphasizes the importance of recognizing and reporting metaplastic elements in primary breast tumors, as well as the value of direct morphologic comparison of cytologic material from FNABs with archival histologic material. In such situations, the importance of complete and accurate clinicopathologic information is underscored. Diagn. Cytopathol. 25:285–291, 2001. © 2001 Wiley‐Liss, Inc.
Adenosine and synaptic plasticity
Authors: de Mendonça Alexandre , Ribeiro Joachim A.
Published: August 2002

Adenosine modulates long‐term synaptic plasticity. Application of adenosine A1 receptor agonists attenuates long‐term potentiation (LTP) in the hippocampus. Endogenous adenosine exerts a tonic inhibitory effect on LTP, since A1 receptor antagonists consistently facilitate LTP. Adenosine also modulates the reciprocal phenomenon of synaptic plasticity, long‐term depression (LTD), and depotentiation in a way that depends on the specific induction protocol. Application of adenosine A2A receptor agonists can facilitate LTP, but the role of endogenous adenosine mediated through A2A receptors in the modulation of synaptic plasticity is still the subject of controversy. The effects of adenosine on synaptic plasticity mediated through A3 receptors have been described. In accordance with the notion that synaptic plasticity is the basis for learning and memory in different brain areas, adenosine correspondingly modulates behavior in various learning and memory paradigms. The effects of adenosine on synaptic plasticity should be relevant for the enhancement of intellectual performance related to caffeine intake. Adenosinergic compounds might prove helpful in the treatment of memory disorders. Drug Dev. Res. 52:283–290, 2001. © 2001 Wiley‐Liss, Inc.
Pyrazolo[4,3‐e]1,2,4‐triazolo[1,5‐c]pyrimidine derivatives as adenosine receptor ligands: A starting point for searching A2B adenosine receptor antagonists
Authors: Baraldi Pier Giovanni , Cacciari Barbara , Romagnoli Romeo , Klotz Karl‐Norbert , Spalluto Giampiero , Varani Katia , Gessi Stefania , Merighi Stefania , Borea Pier Andrea
Published: August 2002

A series of novel pyrazolo[4,3‐e]1,2,4‐triazolo[1,5‐c]pyrimidine substituted at N8 pyrazole nitrogen and at the 5‐amino group was synthesized and their affinities to all four cloned human adenosine receptor subtypes were evaluated by competition binding assays using [3H]‐DPCPX (A1 and A2B), [3H]‐SCH 58261 (A2A), and [3H]‐MRE3008‐F20 (A3) as radioligands. In particular, the structural requirements necessary for adenosine A2B receptor recognition were investigated. These preliminary results confirm that the free amino group at the 5‐position confers better A2B affinity, while the effect of the chain at nitrogen pyrazole nucleus, the 8‐position, seems to be preferred with respect to the corresponding N7 regioisomers. The introduction of an aminoacyl chain at the 5‐amino group produces better selectivity for A2B receptors vs. A2A, but the compounds still remain more potent for A1 and a significant decrease (about 5‐fold) of affinity at A2B receptors was observed. Surprisingly, with these polar chains a good affinity at human A3 adenosine receptors was also detected. The most interesting compounds in binding studies proved to be potent antagonists (nM range) in functional assays, measuring the inhibition of cAMP production induced by 100 nM NECA. Drug Dev. Res. 53:225–235, 2001. © 2001 Wiley‐Liss, Inc.