bluuebunny/crossref_metadata_2025 huggingface dataset:
The myosin power stroke
Authors: Tyska Matthew J. , Warshaw David M.
Published: August 2002

Optical trapping technology now allows investigators in the motility field to measure the forces generated by single motor molecules. A handful of research groups have exploited this approach to further develop our understanding of the actin‐based motor, myosin, an ATPase that is capable of converting chemical energy into mechanical work during a cyclical interaction with filamentous actin. In this regard, myosin‐II from muscle is the most well‐characterized myosin superfamily member. By combining the data obtained from optical trap assays with that from ensemble biochemical and mechanical assays, this review discusses the fundamental properties of the myosin‐II power stroke and, perhaps more significantly, how these properties are governed by this molecule's atomic structure and the biochemical transitions that define its catalytic cycle. Cell Motil. Cytoskeleton 51:1–15, 2002. © 2002 Wiley‐Liss, Inc.
Introduction to Floquet theory: The calculation of spinning sideband intensities in magic‐angle spinning NMR
Authors: Bain Alex D. , Dumont R. S.
Published: August 2002

In magic‐angle spinning, the Hamiltonian of the system changes periodically with time, so the spectrum shows sidebands at multiples of the rotor frequency. This changing Hamiltonian (and hence, the changing Liouvillian) complicates the simulation of the line shape considerably. A simple case is that of a spin‐½ with an anisotropic chemical shift, spinning at the magic angle. Perhaps the most famous solutions to this problem of calculating spinning sideband intensities are those of Herzfeld and Berger and Maricq and Waugh, but there are many alternatives. Floquet theory is a very powerful approach, which we describe here. We illustrate the theory by explicit calculation of the sideband patterns. Floquet theory works by expanding the periodic (due to sample spinning) Hamiltonian into a Fourier series. The time‐independent Fourier components become the blocks in a much larger, time‐independent, effective Hamiltonian. The same can be done with the Liouvillian superoperator. The effective Hamiltonian (or Liouvillian) can then be treated using familiar methods used for time‐independent problems. The considerable increase in size of the problem is normally anathema, and it offers no particular benefit in the specific case treated here. The power of the method is its generality. Regardless of the complexity of the time dependence of the Hamiltonian, the Floquet approach is the same. Therefore, learning how to calculate sideband intensities in this way gives us the tools to solve much more difficult problems. © 2001 John Wiley & Sons, Inc. Concepts Magn Reson 13: 159–170, 2001
Histopathology and MIB‐1 labeling index predicted recurrence of meningiomas
Authors: Ho Donald Ming‐Tak , Hsu Chih‐Yi , Ting Ling‐Tan , Chiang Hung
Published: August 2002

BACKGROUND

Although various histopathologic features have been associated with aggressive behavior or recurrence of meningiomas, there is little agreement about which features are the most important and in what combination. The objective of this study was to formulate diagnostic criteria for atypical meningioma.

METHODS

Eighty‐three patients with meningiomas who underwent macroscopic total resection and had been followed until they developed recurrent disease or for at least 10 years were studied. Thirteen histopathologic parameters that related to recurrence of the tumor were evaluated in each patient. All possible combinations of histologic parameters that were related significantly to recurrence were used to formulate scoring models. The model that included the fewest parameters and that could distinguish tumor recurrence best within 10 years was chosen as the final model.

RESULTS

The final model included three parameters: loss of architecture, mitoses ≥ 1.5/mm2, and necrosis. Of the 52 tumors with a score < 2 (0 or 1 of the 3 parameters), all except 1 tumor did not recur within 10 years, and they were all considered benign meningiomas. Of the 31 tumors with a score ≥ 2 (2 or 3 of the 3 parameters), 94% recurred within 10 years (76% recurred within 5 years), and they were considered atypical meningiomas. The estimated 5‐year and 10‐year recurrence rates for the benign meningiomas were 0.0% and 1.9%, respectively, for benign meningiomas and 71.0% and 93.5%, respectively, for atypical meningiomas (P < 0.001). The estimated 5‐year and 10‐year mortality rates also were significantly different (0.0% and 0.0% vs. 22.1% and 26.7%, respectively; P < 0.001). The MIB‐1 labeling index (LI) for the entire group studied ranged from 0.4 to 33.5 (mean LI, 8.4). Fifty‐two tumors with an LI of < 10 did not recur within 10 years. Of the 31 tumors with an LI ≥ 10, 97% recurred (71% within 5 years).

CONCLUSIONS

Histopathology and MIB‐1 LI were able to predict clinical outcomes of patients with meningioma. The authors propose that atypical meningioma may be diagnosed when two of the following three criteria are present: loss of architecture, mitoses ≥ 1.5/mm2, and necrosis. Cancer 2002;94:1538–47. © 2002 American Cancer Society.

DOI 10.1002/cncr.10351
HER‐2/neuoverexpression in patients with radically resected nonsmall cell lung carcinoma
Authors: Selvaggi Giovanni , Scagliotti Giorgio V. , Torri Valter , Novello Silvia , Leonardo Eugenio , Cappia Susanna , Mossetti Claudio , Ardissone Francesco , Lausi Paolo , Borasio Piero
Published: August 2002

BACKGROUND

Using immunohistochemistry, the authors prospectively investigated the expression of HER‐2/neuprotein in radically resected specimens of nonsmall cell lung carcinoma (NSCLC) and evaluated its impact on long‐term prognosis.

METHODS

Between January 1991 and February 1992, surgical specimens from 130 consecutive patients who underwent radical resection for NSCLC (60 squamous cell carcinoma, 48 adenocarcinoma cases, and 22 large cell carcinomas) and that were staged (according to the TNM staging system) pathologically as Stage I (41 cases [ 32%]), Stage II (37 cases [28%]), and Stage IIIA (52 cases [40%]) were investigated for the expression of HER‐2/neuusing an avidin‐biotin complex immunohistochemical technique. A semiquantitative four‐stage grading system was used (0%, 1–5%, 6–20%, and > 20% positive cells) and an average number of 1500 cells/section was considered. Data were correlated with clinical and pathologic variables.

RESULTS

Normal bronchial tissue was found to be completely negative for HER‐2/neuexpression whereas 21 of the 130 tumor specimens (16%) were positive (range 1–> 20%). HER‐2/neupositivity did not appear to differ significantly among pathologic stages and histotypes. Using a predetermined cutoff value of 5% positive cells, 15 tumor specimens (12%) were found to be above this value. The median survival time (85 weeks vs. 179 weeks) and overall survival rate were significantly lower in patients with > 5% HER‐2/neu‐positive tumors (hazard ratio for the group with > 5% positive cells: 2.94, 95% confidence interval, 1.62–5.34;P< 0.0004). On multivariate analysis, HER‐2/neuand extent of tumor emerged as independent factors for disease‐related mortality.

CONCLUSIONS

In NSCLC, the negative impact of HER‐2/neuoverexpression on survival was maintained in the long‐term follow‐up of radically resected patients. HER‐2/neuoverexpression may be a valuable prognostic factor as well as a potential target for biologic therapies. Cancer 2002;94:2669–74. © 2002 American Cancer Society.

DOI 10.1002/cncr.10531
Liposomal daunorubicin (DaunoXome) plus dexamethasone for patients with multiple myeloma
Authors: Mohrbacher Ann F. , Gregory Stephanie A. , Gabriel Don A. , Rusk Jason M. , Giles Francis J.
Published: August 2002

BACKGROUND

Liposomal daunorubicin is an effective cytotoxic agent in patients with Kaposi sarcoma and hematologic malignancies. Anthracycline‐based chemotherapy regimens, such as vincristine/doxorubicin/dexamethasone (VAD), are standard in the treatment of patients with multiple myeloma (MM). Cardiotoxicity remains a limiting factor in dose escalation of anthracyclines, and multidrug resistance (MDR) develops rapidly on exposure to anthracyclines. Liposomal daunorubicin was designed in an attempt to overcome MDR and to reduce anthracycline‐related toxicities. Thus, an open‐label, Phase II clinical study was conducted by the International Oncology Study Group to assess the efficacy and safety of intravenous liposomal daunorubicin at a dose of 100 mg/m2 given every 3 weeks for a maximum of 6 cycles in patients with recently diagnosed MM (n = 4 patients) or recurrent/refractory MM (n = 37 patients).

METHODS

Liposomal daunorubicin was administered as a single agent for the initial two cycles of therapy, and dexamethasone was added to all subsequent cycles. The primary study end point was response rates. Thirty‐eight patients were treated, 35 of whom were evaluable for response.

RESULTS

A partial response was achieved in six patients (17%), including one patient with disease that previously was refractory to VAD therapy. Stable disease was observed in 22 patients (63%). The principal toxicity was myelosuppression. Grade 3 or 4 hematologic toxicities included granulocytopenia (26%), anemia (Grade 3 only; 11%), thrombocytopenia (11%), and febrile neutropenia (13%). The median survival in 35 patients with recurrent disease was 7.6 months.

CONCLUSIONS

Liposomal daunorubicin had activity in this population of poor‐risk patients that was comparable to the activity of standard regimens. Further studies of this agent in combination with other anti‐MM agents are warranted. Cancer 2002;94:2645–52. © 2002 American Cancer Society.

DOI 10.1002/cncr.10561
Decreasing incidence rates of primary central nervous system lymphoma
Authors: Kadan‐Lottick Nina S. , Skluzacek Maria C. , Gurney James G.
Published: August 2002

BACKGROUND

Incidence rates of primary central nervous system lymphomas (PCNSL) in the U.S. were reported to have increased dramatically during the 1980s and early 1990s. Recent reports portray a continuation of this trend. With potential etiologic factors related to immunosuppression changing, the authors hypothesized that the incidence of PCNSL would be stabilizing.

METHODS

The authors analyzed age specific, gender specific, and race specific PCNSL incidence rates from 1973–1998 using data from the Surveillance, Epidemiology, and End Results (SEER) program. To estimate the impact of the acquired immunodeficiency syndrome (AIDS) and organ transplantation on PCNSL trends, the authors evaluated incidence data from the Centers for Disease Control and Prevention HIV [human immunodeficiency virus]/AIDS Surveillance Report, and the United Network for Organ Sharing.

RESULTS

PCNSL incidence rates decreased from a peak of 10.2 per 1 million person‐years in 1995 to 5.1 per 1 million person‐years in 1998, a decrease that was largely attributable to a decrease in the incidence of the disease in males age ≤ 59 years. The annual rate among those age ≥ 60 years essentially has remained unchanged since 1994, at approximately 16 per 1 million person‐years. Since the early 1980s, regardless of age, PCNSL incidence rates were higher in males than in females, and higher in blacks than in whites. Concordant with PCNSL trends, AIDS rates have decreased since their peak in 1993. However, the rate of solid organ transplantations has increased steadily since 1990.

CONCLUSIONS

In contrast to recent reports of a progressively increasing incidence, the authors found that PCNSL rates have been decreasing in the majority of demographic groups in the U.S since the mid‐1990s. A notable exception was observed in the highest PCNSL risk group, those age ≥ 60 years. Cancer 2002;95:193–202. © 2002 American Cancer Society.

DOI 10.1002/cncr.10643
Seasonal changes in the densities of α2‐noradrenergic receptors are inversely related to changes in testosterone and the volumes of song control nuclei in male European starlings
Authors: Riters Lauren V. , Eens Marcel , Pinxten Rianne , Ball Gregory F.
Published: August 2002

The functions of song and the contextual cues that elicit song change seasonally in parallel with testosterone (T) concentrations in male European starlings. T is high in spring when at least one function of male song is that of immediate mate attraction, and low outside the context of breeding, when starlings primarily use song for dominance or flock maintenance. Several brain nuclei that control song contain high densities of α2‐adrenergic receptors. T can regulate the density of α2‐adrenergic receptors in the avian brain, indicating that the density of α2‐adrenergic receptors within the song system might change seasonally. Although the function of seasonal brain variation is not entirely clear, in many songbirds the volumes of song nuclei are largest when T is high and males sing most. Male starlings, however, sing both when T is high and when T is low. Therefore, exploring seasonal changes in T and the volumes of song nuclei could provide insight into the function of these changes. The present study was performed to explore the relationships among T, the volumes of song nuclei, and the densities of α2‐adrenergic receptors within the song system of male starlings. Song nuclei (the high vocal center [HVc], robust nucleus of the archistriatum [RA], and Area X) were largest, T was highest, and the density of α2‐adrenergic receptors (within HVc and RA) was lowest during the breeding season. The reverse pattern was observed outside of the breeding season. These results suggest that changes in T, volumes of song nuclei, and α2‐receptor densities might regulate seasonal changes in song behavior or the context that will elicit song in male starlings. J. Comp. Neurol. 444:63–74, 2002. © 2002 Wiley‐Liss, Inc.
CART peptide‐immunoreactive projection from the nucleus accumbens targets substantia nigra pars reticulata neurons in the rat
Authors: Dallvechia‐Adams Stephanie , Smith Yoland , Kuhar Michael J.
Published: August 2002

Cocaine and amphetamine regulated transcript (CART) was originally identified as a mRNA which increases in the striatum after acute cocaine or amphetamine administration in rats. In addition, intra‐ventral tegmental (VTA) area injections of CART peptides produce psychostimulant‐like behavioral effects. CART peptide immunoreactivity (CARTir) has been localized in discrete nuclei throughout the brain, and, within the striatum, it is located only ventrally in a subpopulation of medium spiny projection neurons in the shell and core of the nucleus accumbens. To better understand the potential role of CART peptides in the mechanism of action of psychomotor stimulants, we analyzed the distribution and synaptic connectivity of CARTir terminals in the ventral midbrain. CARTir terminal‐like varicosities were located throughout the rostrocaudal extent of the substantia nigra (SN), VTA, and retrorubral field (RRF). They were particularly abundant in the dorsomedial SN where they overlapped with non‐dopaminergic substantia nigra pars reticulata (SNr) neurons and proximal dendrites of dopaminergic substantia nigra pars compacta (SNc) neurons. CARTir terminals were also in register with dopaminergic perikarya in the ventromedial part of the rostral SNc. In many instances, CARTir terminals ensheathed dendrites of SNr neurons. To characterize the postsynaptic targets and potential sources of CARTir terminals in the SN, electron microscopic observations were conducted. Ninety percent of the CARTir terminals examined displayed the ultrastructural features of boutons of striatal origin and 80% of them formed symmetric synapses with distal dendrites of SNr neurons. To further elucidate the source of CARTir terminals in the SN, unilateral excitotoxic lesions directed to the core of the nucleus accumbens (Acc) were produced; this led to a dramatic, almost complete loss of CARTir terminal staining in the ipsilateral SN, whereas the density of CARTir terminals was relatively unchanged in the VTA. In conclusion, this study demonstrates the presence of CART peptides in a direct pathway from the accumbens to the SNr, thus illustrating a unique feature of CART peptides in that they delineate a specific anatomical circuit of the basal ganglia. J. Comp. Neurol. 434:29–39, 2001. © 2001 Wiley‐Liss, Inc.
Transcriptional profiling reveals strict boundaries between hippocampal subregions
Authors: Zhao Xinyu , Lein Edward S. , He Aiqing , Smith Stanley C. , Aston Christopher , Gage Fred H.
Published: August 2002

The hippocampus consists of distinct anatomic regions that have been demonstrated to have different biological functions. To explore the molecular differences between hippocampal subregions, we performed transcriptional profiling analysis by using DNA microarray technology. The cRNA derived from the CA1, CA3, and dentate gyrus regions of the hippocampus and from spinal cord was hybridized to Affymetrix high‐density oligo arrays. This systematic approach revealed sets of genes that were expressed specifically in subregions of the hippocampus corresponding to predefined cytoarchitectural boundaries, which could be confirmed by in situ hybridization and Real Time quantitative polymerase chain reaction. The relative enrichment and absence of genes in the hippocampal subregions support the conclusion that there is a molecular basis for the previously defined anatomic subregions of the hippocampus and also reveal genes that could be important in defining the unique functions of the hippocampal subfields. J. Comp. Neurol. 441:187–196, 2001. © 2001 Wiley‐Liss, Inc.
Commissurally projecting inhibitory interneurons of the rat hippocampal dentate gyrus: A colocalization study of neuronal markers and the retrograde tracer fluoro‐gold
Authors: Zappone Colin A. , Sloviter Robert S.
Published: August 2002

Improved methods for detecting neuronal markers and the retrograde tracer Fluoro‐Gold (FG) were used to identify commissurally projecting neurons of the rat hippocampus. In addition to the dentate hilar mossy cells and CA3 pyramidal cells shown previously to transport retrograde tracers after injection into the dorsal hippocampus, FG‐positive interneurons of the dentate granule cell layer and hilus were detected in numbers greater than previously reported. FG labeling of interneurons was variable among animals, but was as high as 96% of hilar somatostatin‐positive interneurons, 84% of parvalbumin‐positive cells of the granule cell layer and hilus combined, and 33% of hilar calretinin‐positive cells. By comparison, interneurons of the dentate molecular layer and all hippocampal subregions were conspicuously FG‐negative. Whereas hilar mossy cells and CA3 pyramidal cells were FG‐labeled throughout the longitudinal axis, FG‐positive interneurons exhibited a relatively homotopic distribution. “Control” injections of FG into the neocortex, septum, and ventral hippocampus demonstrated that the homotopic labeling of dentate interneurons was injection site‐specific, and that the CA1‐CA3 interneurons unlabeled by contralateral hippocampal FG injection were nonetheless able to transport FG from the septum. These data suggest a hippocampal organizing principle according to which virtually all commissurally projecting hippocampal neurons share the property of being monosynaptic targets of dentate granule cells. Because granule cells innervate their exclusively ipsilateral target cells in a highly lamellar pattern, these results suggest that focal granule cell excitation may result in commissural inhibition of the corresponding “twin” granule cell lamella, thereby lateralizing and amplifying the influence of the initiating discharge. J. Comp. Neurol. 441:324–344, 2001. © 2001 Wiley‐Liss, Inc.
The concept of correlated colour temperature revisited
Authors: Borbély Ákos , Sámson Árpád , Schanda János
Published: August 2002

Correlated colour temperature is a one‐dimensional description of the colour of near‐white light sources. The concept relates the numerical value to a visual observation of smallest colour difference between the chromaticity of the test source and of a point lying on the Planckian locus. In practice, chromaticity difference on a uniform chromaticity scale diagram is used. Since the introduction of the CIELUV and CIELAB spaces, it has been questioned whether the calculations should be done on the traditional u,v diagram, or by using a more equidistant colour space. Based on our visual experiments, we can state that the u,v diagram‐based calculation is adequate to describe the correlated colour temperature of a source. The individual scatter of observations is so large that a visual definition has no practical reality. Thus, we recommend changing the definition of correlated colour temperature from a visual definition to a mathematical one and dropping any reference to visual investigations. © 2001 John Wiley & Sons, Inc. Col Res Appl, 26, 450–457, 2001
A distributed implementation of a virtual machine for Java
Authors: Aridor Yariv , Factor Michael , Teperman Avi
Published: August 2002

The cluster virtual machine (VM) for Java provides a single system image of a traditional Java Virtual Machine (JVM) while executing in a distributed fashion on the nodes of a cluster. The cluster VM for Java virtualizes the cluster, supporting any pure Java application without requiring that application be tailored specifically for it. The aim of our cluster VM is to obtain improved scalability for a class of Java Server Applications by distributing the application's work among the cluster's computing resources. The implementation of the cluster VM for Java is based on a novel object model which distinguishes between an application's view of an object (e.g. every object is a unique data structure) and its implementation (e.g. objects may have consistent replications on different nodes). This enables us to exploit knowledge on the use of individual objects to improve performance (e.g. using object replications to increase locality of access to objects).

We have already completed a prototype that runs pure Java applications on a cluster of NT workstations connected by a Myrinet fast switch. The prototype provides a single system image to applications, distributing the application's threads and objects over the cluster. We used the cluster VM to run, without change, arealJava Server Application containing over 10 Kloc

Kloc means Kilo lines of code—used to describe the size of applications in terms of source lines count.

for the source code and achieved high scalability for it on a cluster. We also achieved linear speedup for another application with a large number of independent threads. This paper discusses the architecture and implementation of the cluster VM. It focuses on achieving a single system image for a traditional JVM on a cluster while describing, in short, how we aim to obtain scalability. Copyright © 2001 John Wiley & Sons, Ltd.
Java for high‐performance network‐based computing: a survey
Authors: Lobosco M. , Amorim C. , Loques O.
Published: August 2002

There has been an increasing research interest in extending the use of Java towards high‐performance demanding applications such as scalable Web servers, distributed multimedia applications, and large‐scale scientific applications. However, extending Java to a multicomputer environment and improving the low performance of current Java implementations pose great challenges to both the systems developer and application designer. In this survey, we describe and classify 14 relevant proposals and environments that tackle Java's performance bottlenecks in order to make the language an effective option for high‐performance network‐based computing. We further survey significant performance issues while exposing the potential benefits and limitations of current solutions in such a way that a framework for future research efforts can be established. Most of the proposed solutions can be classified according to some combination of three basic parameters: the model adopted for inter‐process communication, language extensions, and the implementation strategy. In addition, where appropriate to each individual proposal, we examine other relevant issues, such as interoperability, portability, and garbage collection. Copyright © 2002 John Wiley & Sons, Ltd.
Effects of population density on the spread of disease
Authors: Tarwater Patrick M. , Martin Clyde F.
Published: August 2002

The effect of population density on the epidemic outbreak of measles or measles‐like infectious diseases was evaluated. Using average‐number contacts with susceptible individuals per infectious individual as a measure of population density, an analytical model for the distribution of the nonstationary stochastic process of susceptible contact is presented. A 5‐dimensional lattice simulation model of disease spread was used to evaluate the effects of four different population densities. A zero‐inflated Poisson probability model was used to quantify the nonstationarity of the contact rate in the stochastic epidemic process. Analysis of the simulation results identified a decrease in a susceptible contact rate from four to three, resulted in a dramatic effect on the distribution of contacts over time, the magnitude of the outbreak, and, ultimately, the spread of disease. © 2001 John Wiley & Sons, Inc.
The evolution of an evidence‐based programme for problem drinking: treatment components
Authors: Long C. G. , Kidger T. , Hollin C. R.
Published: August 2002

The development and evaluation of an evidence‐based treatment for problem drinking is described. In addition to a clear description of the treatment programme, emphasis is placed on the management of change within mental health settings, treatment integrity and an ongoing process of audit and evaluation. Implications for future service development are discussed. Copyright © 2001 John Wiley & Sons, Ltd.
A systematic procedure for synthesizing two‐terminal devices with polynomial non‐linearity
Authors: Zhong Guo‐Qun , Ko King‐Tim , Man Kim‐Fung , Tang Kit‐Sang
Published: August 2002

In this paper, a systematic procedure for synthesizing two‐terminal devices with polynomial non‐linearity is proposed. A two‐terminal, or one‐port, device with an arbitrary polynomial non‐linearity can be designed using the proposed procedure in a step‐by‐step systematic manner. A variety of driving‐point characteristics of two‐terminal devices with synthesized polynomial non‐linearity, both numerically calculated and experimentally measured, are demonstrated. Copyright © 2001 John Wiley & Sons, Ltd.
CNN applications from the hardware point of view: video sequence segmentation
Authors: Kananen Asko , Paasio Ari , Laiho Mika , Halonen Kari
Published: August 2002

In this paper, the problems present in hardware implementations of cellular non‐linear network (CNN) type parallel processors are discussed. Instead of designing a multipurpose processor, or even a full image size application specific parallel processor, we suggest a division of the processing task into categories depending on the cell dynamics and on the spread of the influence of a cell. In this way, drastic savings can be achieved in silicon size and in processing speed. As an example, we use a CNN algorithm that was designed for video image segmentation for object‐based compression of video signal. We start with discussion of the problems related to implementation of the algorithm with current multipurpose processors. We then introduce hardware structures that can be used in obtaining certain functionalities. In the same section, we also deal with the division of the processing task. We also compare the introduced hardware solution for the algorithm with multipurpose processor structures in silicon size, power consumption and in processing speed. Copyright © 2002 John Wiley & Sons, Ltd.
Template design methods for binary stable cellular neural networks
Authors: Gilli Marco , Paolo Civalleri Pier
Published: August 2002

Stable cellular neural networks with binary outputs implement a non‐linear mapping between sets of input and output images. Such a mapping is studied in detail. We prove two theorems: the first one yields a sufficient condition in order that the non‐linear mapping be well‐defined; the second one yields a condition, that allows to describe the mapping through a simple algorithm based on the sign of the initial derivatives. Then we enunciate two additional theorems and two corollaries, that identify the class of templates satisfying the above condition: such a class is shown to be rather large and include, as particular cases, the monotonic templates, and several kinds of non‐monotonic templates. Finally,a rigorous design procedure is proposed. Copyright © 2002 John Wiley & Sons, Ltd.
A cellular neural network based optical range finder
Authors: Zanela Andrea , Taraglio Sergio
Published: August 2002

An optical range finder based on the CNN paradigm is presented. It exploits a variational formulation of the stereo‐vision problem. The device characteristics are assessed and some experiments are presented relative to two robotic tasks: the self‐localization of an autonomous vehicle and an obstacle detection system. Copyright © 2002 John Wiley & Sons, Ltd.
A CNN framework for modeling parallel processing in a mammalian retina
Authors: Bálya Dávid , Roska Botond , Roska Tamás , Werblin Frank S.
Published: August 2002

We present here a simple multi‐layer cellular neural/non‐linear network (CNN) model of the mammalian retina, capable of implementation on CNN Universal Machine (CNN‐UM) chips. The basis of the model is a simple multi‐layer cellular neural/non‐linear Network (IEEE Trans. Circuits Systems1988;35:1257;IEEE Trans. Circuits Systems1993;40:147). The characterization of the elements in the CNN model is based on anatomical and physiological studies performed in the rabbit retina. The living mammalian retina represents the visual world in a set of about a dozen different ‘feature detecting’ parallel representations (Nature2001;410:583–587). Our CNN model is capable of reproducing qualitatively the same full set of space–time patterns as the living retina in response to a flashed square. The modelling framework can then be used to predict the set of retinal responses to more complex patterns and is also applicable to studies of the other biological sensory systems. The work represents a major step forward in the complexity and programmability of retinal models. Copyright © 2002 John Wiley & Sons, Ltd.
T‐cell subset counting and the fight against AIDS: Reflections over a 20‐year struggle
Authors: Mandy Francis , Nicholson Jan , Autran Brigitte , Janossy George
Published: August 2002

The story of T‐lymphocyte subset immunophenotyping technology is reviewed on the occasion of the 20th anniversary of CD4 T‐cell enumeration. Over time, immunophenotyping has evolved into precise, reliable, but complicated and expensive technology requiring fresh blood samples. The gating technologies that were universally adapted for clinical flow cytometry for the past decade relied on rapidly deteriorating morphological scatter characteristics of leukocytes. This special issue dedicated to CD4 T‐cell enumeration features most of the available new options that will have a significant impact on how this technology will be implemented within the first decade of the 21st century. In a series of original publications, including the new NIH guideline for T‐cell subset enumeration, contemporary gating protocols that use immunologically logical parameters are presented as part of the more reliable and affordable immunophenotyping alternative. Some of the improvements addressed here include the costs of the assays and the capacity to monitor interlaboratory and intralaboratory performances. It is clear that an effective attack on the human immunodeficiency virus (HIV) epidemic has to embrace resource‐poor regions. Reducing the cost of the assay while improving reliability and durability is a move in the right direction. Cytometry (Clin. Cytometry) 50:39–45, 2002. © 2002 Wiley‐Liss, Inc.
Reducing cell loss in banyan based ATM switching fabrics
Authors: Al‐Mouhamed M. , Kaleemuddin M. , Youssef H.
Published: August 2002

In this paper, we propose a new technique for reducing cell loss in multi‐banyan‐based ATM switching fabrics. We propose a switch architecture that uses incremental path reservation based on previously established connections. Path reservation is carried out sequentially within each banyan but multiple banyan planes can be concurrently reserved. We use a conflict resolution approach according to which banyans make concurrent reservation offers of conflict‐free paths to head of the line cells waiting in input buffers. A reservation offer from a given banyan is allocated to the cell whose source‐to‐destination path uses the largest number of partially allocated switching elements which are shared with previously reserved paths. Paths are incrementallyclusteredwithin each banyan. This approach leaves the largest number of free switching elements for subsequent reservations which has the effect of reducing the potential of future conflicts and improves throughput. We present a pipelined switch architecture based on the above concept ofpath‐clusteringwhich we callpath‐clustering banyan switching fabric(PCBSF). An efficient hardware that implements PCBSF is presented together with its theoretical basis. The performance and robustness of PCBSF are evaluated under simulateduniform trafficandATM traffic. We also compare the cell loss rate of PCBSF to that of other pipelined banyan switches by varying the switch size, input buffer size, and traffic pattern. Copyright © 2001 John Wiley & Sons, Ltd.
Buffer management and scheduling schemes for TCP/IP over ATM‐GFR
Authors: Wu Dapeng , Chao H. Jonathan
Published: August 2002

Today ATM technology is facing challenges from integrated service IP, IP switching, gigabit IP router and gigabit ethernet. Although ATM is approved by ITU‐T as the standard technology in B‐ISDN, its survivability is still in question. Since ATM‐UBR (unspecified bit rate) provides no service guarantee and ATM‐ABR (available bit rate) is still unattainable for most users, many existing users have little or no incentives to migrate to ATM technology. The guaranteed frame rate (GFR) service is introduced to deal with this dilemma. The GFR can guarantee the minimum cell rate (MCR) with fair access to excess bandwidth. This paper studies various schemes to support the GFR. We have studied different discarding and scheduling schemes, and compared their throughput and fairness when TCP/IP traffic is carried. Through simulations, it is shown that only per‐VC queueing with weighted round robin (WRR) can guarantee minimum cell rate. Among all the schemes that have been explored, we recommend dynamic threshold–early packet discard (DT–EPD) integrated with MCR+ (a WRR variant) to support the GFR service. Copyright © 2001 John Wiley & Sons, Ltd.
Application of a new explicit‐rate ABR traffic controller
Authors: Lu Jun , Mir Nader F.
Published: August 2002

In broadband integrated communication systems, the classical method of max–min fair‐rate allocation for traffic control does not support the weighted‐rate guarantee. The weighted‐rate guarantee is necessary for available‐bit rate (ABR) service models. This fact motivates that the weighted max–min (WMM) fair‐rate allocation for the ABR traffic is widely studied. However, the combination of close‐loop feedback control with WMM algorithm has not appeared in the previous research. In this paper, a practical WMM fair‐rate allocation model is proposed. This scheduling scheme combines and integrates the congestion avoidance using proportional control (CAPC) and the weighted max–min fair‐rate allocation. This model is designed to achieve higher utilization and also bounded delay for ABR traffic flow control. In the system under analysis, the performance of this new weighted traffic scheduler is evaluated. The system presented in this paper is also compared with WMM and CAPC methods. Copyright © 2001 John Wiley & Sons, Ltd.
Linear and non‐linear space diversity combining algorithms over fading channels in TDMA systems
Authors: Benson M. , Carrasco R. A.
Published: August 2002

This paper investigates the performances of various adaptive algorithms for space diversity combining in time division multiple access (TDMA) digital cellular mobile radio systems. Two linear adaptive algorithms are investigated, the least mean square (LMS) and the square root Kalman (SRK) algorithm. These algorithms are based on the minimization of the mean‐square error. However, the optimal performance can only be obtained using algorithms satisfying the minimum bit error rate (BER) criterion. This criterion can be satisfied using non‐linear signal processing techniques such as artificial neural networks. An artificial neural network combiner model is developed, based on the recurrent neural network (RNN) structure, trained using the real‐time recurrent learning (RTRL) algorithm. It is shown that, for channels characterized by Rician fading, the artificial neural network combiners based on the RNN structure are able to provide significant improvements in the BER performance in comparison with the linear techniques. In particular, improvements are evident in time‐varying channels dominated by inter‐symbol interference. Copyright © 2001 John Wiley & Sons, Ltd.
Performance analysis of Robust WDM fast circuit‐switched networks with token passing in control channel
Authors: Abd‐Elmalak Samir A. , Vaishnav Chintan , Jayasumana Anura P.
Published: August 2002

WDM networks depend on predetermined, fixed wavelength channels, requiring highly stable lasers and tunable filters. Robust WDM networks, based on dynamically selected wavelengths, relax manufacturing and operating wavelength tolerance requirements leading to low‐cost implementations. A node dynamically selects a currently unused wavelength for communication, and uses it for a limited period of time for communication with a destination, thus allowing the network to tolerate wavelength variation with time. A performance model is presented for Robust WDM networks in which the right to establish WDM connections is arbitrated periodically by a control channel based on token passing. Comparison with simulation results indicates the model's ability to predict the network performance accurately. Copyright © 2002 John Wiley & Sons, Ltd.
Myxopapillary ependymoma: Cytomorphologic characteristics and differential diagnosis
Authors: Kulesza Peter , Tihan Tarik , Ali Syed Z.
Published: August 2002

Myxopapillary ependymoma (ME) is a rare tumor with a predilection for sacrococcygeal area of adults. We present the cytomorphology of one such case in a 21‐yr‐old man, diagnosed by fine‐needle aspiration (FNA). The tumor disclosed biphasic morphology with nests and aggregates of epithelioid malignant cells as well as branching cords of myxohyaline material. Most noticeable was the presence of distinct hyaline globules surrounded by neoplastic cells. The differential diagnosis of ME includes chordoma, adenoid cystic carcinoma, mucinous adenocarcinoma, and germ cell tumor. An accurate preoperative diagnosis of ME on FNA can be achieved based on its distinctive cytomorphologic features. Diagn. Cytopathol. 2002;26:247–250. © 2002 Wiley‐Liss, Inc.
Adenosine deaminase‐deficient mice as models for adenosine‐mediated lung inflammation and damage
Authors: Blackburn Michael R. , Zhong Hongyan
Published: August 2002

Adenosine has been implicated to play a role in the inflammatory lung disease, asthma; however, there are few in vivo model systems with which to study the role of adenosine in aspects of this disease. We recently generated mice deficient in the purine catabolic enzyme adenosine deaminase (ADA) that controls the levels of adenosine in tissues and cells. Results presented here demonstrate that elevated adenosine levels in ADA‐deficient mice result in abnormal lung development and the promotion of lung inflammation and damage. ADA‐deficient mice exhibit alveolar defects that are overcome by biochemically restoring ADA enzymatic activity to these animals. In addition, lowering ADA substrates in the lung using enzyme therapy reverses lung eosinophilia and mucus production. These results suggest that elevated adenosine, and perhaps abnormal adenosine signaling, are implicated in abnormal lung development and lung inflammation and damage in ADA‐deficient mice. These mice will therefore serve as useful in vivo models in which to study the role of purinergic signaling in aspects of lung development and disease. Drug Dev. Res. 52:416–423, 2001. © 2001 Wiley‐Liss, Inc.
P2X7 nucleotide receptor: Modulation of LPS‐induced macrophage signaling and mediator production
Authors: Watters Jyoti J. , Sommer Julie A. , Fisette Philip L. , Pfeiffer Zachary A. , Aga Mini , Prabhu Usha , Guerra Alma N. , Denlinger Loren C. , Bertics Paul J.
Published: August 2002

During infection or inflammation, high concentrations of extracellular nucleotides are released into the inflammatory microenvironment, supplying a source of ligand for purinergic receptors that are present on many immune cell types. The P2X7 receptor, a member of the P2X purinergic receptor family of ATP‐gated ion channels, is thought to play an important role in monocyte/macrophage activation. One factor that can powerfully activate macrophages is bacterial lipopolysaccharide (endotoxin, LPS) and although the mechanisms involved in this process are not well understood, it is clear that LPS activation of macrophages is central to the development of septic shock in response to Gram‐negative bacteria. Several lines of evidence have demonstrated strong modulatory effects of adenine nucleotides on the events associated with LPS stimulation of macrophages. Further, because the signal transduction cascades initiated in macrophages upon LPS exposure are similar to those resulting from P2X7 receptor stimulation, and because antagonism of the P2X7 receptor can attenuate LPS‐stimulated signaling events and mediator release, the P2X7 receptor has been implicated in the control of macrophage responses to LPS. In addition, our laboratory has identified a consensus LPS‐binding motif at the extreme carboxyl terminus of the P2X7 receptor, further supporting the potential for a direct interaction between LPS and this purinergic receptor. In this review, we discuss potential regulatory domains and structural features of the P2X7 receptor and outline some of the signal transduction pathways activated by P2X7 receptor agonists. Moreover, we present evidence supporting a critical role for the P2X7 receptor in modulating or mediating some of the biological effects of LPS in macrophages. Drug Dev. Res. 53:91–104, 2001. © 2001 Wiley‐Liss, Inc.
Customer participation in creating site brand loyalty
Authors: Holland Jonna , Baker Stacey Menzel
Published: August 2002

This article explores the development of an e-business marketing model that capitalizes on customer participation and the likely consequences of such efforts, principally site brand loyalty. A conceptual model illustrates how consumers’ goals in visiting a website (task or experiential) affect their propensity to be site brand loyal and how characteristics of the site, including personalization and community, are related to brand loyalty. The model also shows that creating site brand loyalty leads to predictable affective, cognitive, and behavioral outcomes from customers, such as repeat visits to and patronage of the site, fewer intentions to defect to competitors, and more favorable attitudes toward the site. Case studies of corporate websites provide empirical evidence to support the model. The paper concludes by suggesting that customer participation in the e-business model fundamentally changes the way brands are developed. That is, producers no longer create an image for a brand and pass it on to the consumer; instead, the producer and consumer are interactively creating the e-business brand.
Cell proliferation during blastema formation in the regenerating teleost fin
Authors: Santos‐Ruiz Leonor , Santamaría Jesús A. , Ruiz‐Sánchez Josefa , Becerra José
Published: August 2002

Epimorphic regeneration in teleost fins occurs through the establishment of a balanced growth state in which a blastema gives rise to all the mesenchymal cells, whereas definite areas of the epidermis proliferate leading to its extension, thus, allowing the enlargement of the whole structure. This type of regeneration involves specific mechanisms that temporally and spatially regulate cell proliferation. To understand how the blastema is formed and how this growth situation is set up, we investigated cell proliferation patterns in the regenerating fin of the goldfishCarassius auratusfrom the time of amputation to that of blastema formation by using proliferating cell nuclear antigen immunostaining and bromodeoxyuridine labeling. Wound closure and apical epidermal cap formation took place by epidermal migration and re‐arrangement, without the contribution of cell proliferation. As soon as the apical cap had formed, the epidermis started to proliferate at its lateral surfaces, in which all layers maintained cycling for the duration of the studied process. The distal epidermal cap, on the contrary, presented very few cycling cells, and its cytoarchitecture was indicative of continuous remodeling due to ray growth. The basal layer of this epidermal cap showed a typical morphology and remained nonproliferative whilst in contact with the proliferating blastema. Proliferation in the mesenchymal compartment of the ray started far from the amputation plane. Subsequently, cycling cells approached that location, until they formed the blastema in contact with the apical epidermal cap. Differences observed between the epidermis and mesenchyma, regarding activation of the cell cycle and the establishment of proliferative patterns, suggest that differential mechanisms regulate cell proliferation in each of these compartments during the initial stages of regeneration. © 2002 Wiley‐Liss, Inc.
Regulation of Epha4 expression in paraxial and lateral plate mesoderm by ectoderm‐derived signals
Authors: Schmidt Corina , Christ Bodo , Maden Malcolm , Brand‐Saberi Beate , Patel Ketan
Published: August 2002

Somitogenesis in all vertebrates involves a mesenchymal to epithelial transition of segmental plate cells. Such a transition involves cells altering their morphology and their adhesive properties. The Eph family of receptor tyrosine kinases has been postulated to regulate cytoskeletal organization. In this study, we show that a receptor belonging to this family, EphA4, is expressed in the segmental plate in a region where cells are undergoing changes in cell shape as a prelude to epithelialization. We have identified the ectoderm covering the somites and the midline ectoderm as sources of signals capable of inducing EphA4. Loss of EphA4 results in cells of irregular morphology and somites fail to form. We also show that when somites fail to develop, expression of EphA4 in the lateral plate is also lost. We suggest that signaling occurs between the somites and the lateral plate mesoderm and provide evidence that retinoic acid is involved in this communication. © 2001 Wiley‐Liss, Inc.