bluuebunny/crossref_metadata_2025_split huggingface dataset:
A‐map representations and asymptotically almost periodic responses
Authors: Sandberg Irwin W. 
Published: August 2002

AbstractIt 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

AbstractAn 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

AbstractThis 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

AbstractBackgroundIn 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.MethodsWe 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.ResultsFused 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).ConclusionsThe 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

AbstractBackgroundCaspase 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.MethodsThe 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.ResultsThe 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.ConclusionsCells 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

AbstractPostoperative 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

AbstractSingle‐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

AbstractMobile 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

AbstractIn 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

AbstractThis 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

AbstractMyofibroblastoma 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

AbstractAmyloidosis 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

AbstractThe 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

AbstractCytologic 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

AbstractSimian 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.