bluuebunny/crossref_metadata_2025_split huggingface dataset:
Asymmetrical segregation of chromosomes with a normal metaphase/anaphase checkpoint in polyploid megakaryocytes
Authors: Roy Lydia , Coullin Philippe , Vitrat Natacha , Hellio Raymond , Debili Najet , Weinstein Jasminder , Bernheim Alain , Vainchenker William 
Published: July 2002

Abstract
During differentiation, megakaryocytes increase ploidy through a process called endomitosis, whose mechanisms remain unknown. As it corresponds to abortive mitosis at anaphase and is associated with a multipolar spindle, investigation of chromosome segregation may help to better understand this cell-cycle abnormality. To examine this variation, a new method was developed to combine primed in situ labeling to label centromeres of one chromosome category and immunostaining of tubulin. Human megakaryocytes were obtained from normal bone marrow culture. By confocal microscopy, this study demonstrates an asymmetrical distribution of chromosomes (1 or 7) either between the spindle poles at anaphase stage of endomitosis and between the different lobes of interphase megakaryocyte nuclei. The metaphase/anaphase checkpoint appears normal on the evidence that under nocodazole treatment megakaryocytes progressively accumulate in pseudo-metaphase, without spontaneous escape from this blockage. Immunostaining of p55CDC/hCDC20 with similar kinetochore localization and dynamics as during normal mitosis confirms this result. HCdh1 was also expressed in megakaryocytes, and its main target, cyclin B1, was normally degraded at anaphase, suggesting that the hCdh1-anaphase–promoting complex checkpoint was also functional. This study found the explanation for these unexpected results of an asymmetrical segregation coupled to normal checkpoints by careful analysis of multipolar endomitotic spindles: whereas each aster is connected to more than one other aster, one chromosome may segregate symmetrically between 2 spindle poles and still show asymmetrical segregation when the entire complex spindle is considered.
Platelet/polymorphonuclear leukocyte adhesion: a new role for SRC kinases in Mac-1 adhesive function triggered by P-selectin
Authors: Piccardoni Paola , Sideri Rita , Manarini Stefano , Piccoli Antonio , Martelli Nicola , de Gaetano Giovanni , Cerletti Chiara , Evangelista Virgilio 
Published: July 2002

AbstractAdhesion of polymorphonuclear leukocytes (PMNLs) to activated platelets requires a P-selectin–triggered, tyrosine kinase–dependent adhesiveness of Mac-1 and is accompanied by tyrosine phosphorylation of a 110-kd protein (P-110) in PMNLs. Inhibitors of SRC tyrosine kinases were found to inhibit PMNL adhesion to activated platelets or to P-selectin expressing Chinese hamster ovary (CHO-P) cells and the tyrosine phosphorylation of P-110. Adhesion of PMNLs to activated platelets or to CHO-P cells stimulated activity of LYN and HCK. Monoclonal antibody blockade of P-selectin or β2-integrins reduced the activation of both kinases. In PMNLs either adherent to platelets or aggregated by P-selectin–IgG chimera, Mac-1 was rapidly redistributed to the Triton X-100–insoluble cytoskeletal fraction, and large clusters of Mac-1 colocalized with patches of F-actin at the sites of cell-cell contact. In PMNLs stimulated by P-selectin–IgG chimera, SRC kinase inhibition impaired Mac-1 clustering, F-actin accumulation, and CD18 redistribution to the cytoskeleton. Disruption of the actin filament network by cytochalasin D prevented PMNL-platelet adhesion and P-selectin–induced PMNL aggregation and impaired the clustering of Mac-1. In agreement with the requirement for the β2-integrin in the functional up-regulation of LYN and HCK, integrin blockade by monoclonal antibodies resulted in a complete inhibition of P-selectin–induced Mac-1 clustering and F-actin accumulation. Taken together, the results indicate that, after an initial P-selectin–triggered β2-integrin interaction with the ligand, SRC kinases are activated and allow the remodeling of cytoskeleton-integrin linkages and integrin clustering that finally strengthen cell-cell adhesion. This model highlights a new role for SRC kinases in a regulatory loop by which the Mac-1 promotes its own adhesive function.
Identification of a candidate human neurohematopoietic stem-cell population
Authors: Shih Chu-Chih , Weng Yehua , Mamelak Adam , LeBon Thomas , Hu Mickey C.-T. , Forman Stephen J. 
Published: July 2002

Abstract
It was recently reported that transplantation of clonally derived murine neurosphere cells into sublethally irradiated allogeneic hosts leads to a donor-derived hematopoietic reconstitution. The confirmation of the existence of a common neurohematopoietic stem cell in the human brain will have a significant effect on stem cell research and on clinical transplantation. Here, it is demonstrated that the human fetal brain contains separate but overlapping epidermal growth factor (EGF)–responsive and basic fibroblast growth factor (FGF-2)–responsive neural stem cells. The majority (&gt; 85%) of cells within these EGF- and/or FGF-2–generated neurospheres express characteristic neural stem/progenitor cell markers including nestin, EGF receptor, and FGF-2 receptor. These neural stem cells can be continuously passaged in vitro, and demonstrate a constant 20-fold expansion in every passage for up to the fifth passage (the longest period that has been carried out in the authors' laboratory). These neural stem cells are multipotential for neurons, astrocytes, and oligodendrocytes. After transplantation into SCID-hu mice, all neural stem cells, regardless of passages, culture conditions, and donors, are able to establish long-term hematopoietic reconstitution in the presence of an intact human bone marrow microenvironment.
Missense mutations in the β3 subunit have a different impact on the expression and function between αIIbβ3 and αvβ3
Authors: Tadokoro Seiji , Tomiyama Yoshiaki , Honda Shigenori , Kashiwagi Hirokazu , Kosugi Satoru , Shiraga Masamichi , Kiyoi Teruo , Kurata Yoshiyuki , Matsuzawa Yuji 
Published: July 2002

AbstractαIIbβ3 and αvβ3 belong to the β3integrin subfamily. Although the β3 subunit is a key regulator for the biosynthesis of β3 integrins, it remains obscure whether missense mutations in β3 may induce the same defects in both αIIbβ3 and αvβ3. In this study, it is revealed that thrombasthenic platelets with a His280Pro mutation in β3, which is prevalent in Japanese patients with Glanzmann thrombasthenia, did contain significant amounts of αvβ3 (about 50% of control) using sensitive enzyme-linked immunosorbent assay. Expression studies showed that the His280Proβ3 mutation impaired αIIbβ3 expression but not αvβ3 expression in 293 cells. To extend these findings, the effects of several β3 missense mutations leading to an impaired αIIbβ3expression on αvβ3 function as well as expression was examined: Leu117Trp, Ser162Leu, Arg216Gln, Cys374Tyr, and a newly created Arg216Gln/Leu292Ser mutation. Leu117Trp and Cys374Tyr β3 mutations did impair αvβ3 expression, while Ser162Leu, Arg216Gln, and Arg216Gln/Leu292Ser mutations did not. With regard to ligand binding function, Ser162Leu mutation induced especially distinct effects between 2 β3 integrins: it markedly impaired ligand binding to αIIbβ3 but not to αvβ3 at all. These data clearly demonstrate that the biosynthesis and the ligand binding function of αIIbβ3 and those of αvβ3 are regulated in part by different mechanisms. Present data would be a clue to elucidate the regulatory mechanism of expression and function of β3 integrins.
Conformal Antennas
Authors: Sengupta Dipak L. 
Published: November 2024

AbstractSpecifically, this article describes the following:The specific considerations that must be given to the performance of basic slot and microstrip or patch antenna elements when mounted on nonplanar conducting surfacesA selected number of conformal antennas: for example, microstrip conformal antennas and dielectric‐filled edge slot (DFES) antennasA class of wraparound antennas and antenna arraysCylindrical and spherical phased arrays used for omnidirectional and hemispherical coverage, respectively.
Electromagnetic Surface Waves
Authors: Wu Zhipeng 
Published: November 2024

AbstractIn this article, the electromagnetic surface waves propagating along an interface between two dielectric media or an interface between air and a multilayered structure in planar, cylindrical, and spherical geometries are introduced. Specific surface waves considered are (1) the Zenneck surface wave, (2) the surface wave on a conductor‐backed dielectric slab, (3) the radial cylindrical surface wave on a flat surface, (4) the axial cylindrical surface wave, (5) the surface wave on a dielectric‐coated conducting cylindrical, (6) Norton and trapped surface waves on flat ground interface, (7) surface‐wave propagation over an inhomogeneous flat surface, and (8) surface‐wave propagation over a spherical ground. Several examples are given to illustrate the propagation of surface waves in these geometric structures. The surface waves propagating along Earth's surface have been used for wireless communications and remote sensing. On the other hand, the surface waves on conductor‐backed dielectric slabs become a problem in microwave printed circuits and microstrip antenna systems. The understanding and control of surface waves are therefore important in radio systems.
Electromagnetic Waves in Ionosphere
Authors: Hunsucker Robert D. 
Published: November 2024

AbstractSince the existence of the ionosphere was confirmed in 1925 using radio techniques, we have gained a good understanding of the basic physics and morphology of the solar–terrestrial environment. In this article we summarize the basic physics of the ionosphere and of the interaction of radiowaves with the ionosphere. The fundamental mechanisms of the various radio propagation modes and the effects of solar radiation and noise are described for specific radio services. The principal radio techniques for probing the ionosphere and “frontiers of ionospheric research” are summarized. Three of the principal journals that publish research in the subject of this article areRadio ScienceandJournal of Geophysical Research-Space Physics(published by the American Geophysical Union) andTransactions of the IEEE Group on Antennas and Propagation(published by the Institute of Electrical and Electronic Engineers).
Radio Direction Finding
Authors: Johnson Richard L. , Hipp Jackie E. , Sherrill William M. 
Published: November 2024

AbstractRadio direction finding (DF) is a technique for estimating radiowave angle of arrival (AoA) and is based on prior knowledge of the antenna responses versus AoA.Traditional DF systems exploit rotating antennas or sampled antenna arrays for which the antenna response patterns are very carefully controlled to provide support for closed‐form DF solutions or for the development of steered beams. Sources contributing to DF errors include local scattering, instrumentation, and propagation. Some more recent DF systems exploit array calibration and digital beamforming techniques to provide reliable AoA estimates while accomodating local scattering. Both of these DF system categories are designed for operation against single component plane waves. More sophisticated DF systems now exploit sampled arrays and DF processing to decompose the complex wavefields created by multiple simultaneous signal components.
Packaging RF Devices and Modules
Authors: Lee Y. C. , Zhang Wenge , Su Bingzhi , Feng Zhiping , Gupta K. C. 
Published: November 2024

AbstractRF packaging technologies are advancing rapidly. This article provides basic knowledge to understand the technology advances. Most packaging issues common to those for microelectronics packaging will not be covered here, and they can be found in other articles. The following sections will focus on unique issues for RF packaging. Representative packages and assembly technologies will be reviewed. Critical consideration of RF performance and reliability will be introduced. The reliability section will cover both thermal management and mechanical integrity. A case study will be presented to illustrate a typical design procedure considering various factors. In addition, computer‐aided‐design (CAD) issues and advanced packaging concepts will be introduced, to understand future challenges.
MEI Method
Authors: Mei Kenneth K. 
Published: November 2024

AbstractThe basic principles of the measured equation of invariance (MEI) are presented. To apply the method, one needs to have fundamental knowledge of the finite difference and the integral representation of Maxwell's equations. The details of the formulas needed for solving specific problems are all contained in the cited references, so they are not included in this article. The purpose of this article is to inform the readers of the assumptions and reasoning of the method, the misgivings expressed by other researchers, what type of problems have already been solved by the method, and the latest developments in this method.
Magnetic Shielding
Authors: Fugate David W. , Young Frank S. 
Published: November 2024

Abstract

In traditional usage,
magnetic shielding
refers specifically to shields made of
magnetic
materials like iron and nickel. However, this article is more general because it covers not just traditional magnetic shielding but also shielding of alternating magnetic fields with conducting materials, such as copper and aluminum. In typical applications, shielding eliminates magnetic field interference with electron microscopes, computer displays (CRTs), sensitive electronics, or other devices affected by magnetic fields.
Generalized Scattering Matrix Technique
Authors: Monorchio Agostino , Mittra Raj , Manara Giuliano 
Published: November 2024

AbstractThe generalized scattering matrix (GSM) technique, which is a convenient method for analyzing complex microwave devices, consisting of separable and longitudinally uniform waveguiding structures, is presented in this article. GSM differs from the conventional scattering matrix used in circuit theory or microwave network theory in that it is extended to consider evanescent as well as propagating modes in each waveguide. Some numerical examples are provided to illustrate the importance of the inclusion of higher‐order modes for generating accurate solutions of waveguide discontinuity problems.
Magnetrons
Authors: Osepchuk John M. , Ruden Thomas E. 
Published: November 2024

AbstractThe magnetron has survived in an era when most electron tubes have been replaced by solid‐state devices in modern electronic systems.A wide spectrum of related devices are being developed for specialized applications. These include crossed‐field amplifiers, voltage‐tuned magnetrons, beacon magnetrons, and relativistic magnetrons. Applications range from the classical radar through industrial heating to microwave weapons.Future applications remain unpredictable, but many are being explored. Advances in computer modeling will eventually produce success.
Q‐Factor Measurements
Authors: Luiten Andre 
Published: November 2024

AbstractThis article presents a review of both traditional and modern methods ofQfactor measurement. Many of the techniques to be described were first developed in order to determine theQfactors of resonances falling in the microwave frequency domain.The article commences with a definition of theQfactor and a description of the experimental parameters that need to be measured so as to determine theQfactor of resonance. The various methods for measuring these parameters will then be outlined, including the particular advantages and disadvantages of a technique, the equipment required for the measurement, and its potential for accuracy. Finally, some of the latest developments in the field ofQmeasurement will be presented.
Six‐Port Networks
Authors: Xu Xinyu , Wu Ke , Bosisio Renato G. 
Published: November 2024

AbstractSoftware‐defined radio (SDR) has been identified as a potential method to enhance flexible wireless communication systems. The operation speed of an analog/digital converter (ADC) and processing ability of digital signal processing (DSP) chips are key factors in the development of SDR for useful commercial applications. More recent advances in semiconductor processing technology and the development of reconfigurable devices such as digital signal processors and field‐programmable gate arrays (FPGAs) reduce the development time of commercial products. SDR in conjunction with six‐port receivers has promising applications for use in wireless LANs, audio and television broadcasting, and interoperability between different radio services, as seen by new studies on the use of six‐port technology in various design aspects of a new SDR receiver. The objective is to realize an application of SDR to provide a multichannel, multimode wireless direct digital receiver.The combination of SDR and six‐port technology provides great flexibility in system configuration; significant reduction in hardware cost, particularly at millimeter‐wave frequencies; and potential for software reuse. The six‐port receiver approach offers wideband accommodation to ever‐changing communication specifications required in a SDR as much of its functionality is defined in software. Different types of six‐port circuits have been designed, with center frequencies at 2.4, 5.8, 24, and 28 GHz, operating over wide frequency bands. Some six‐port circuits are based on microstrip structures and are fabricated with hybrid microwave integrated circuit (MHMIC) or monolithic microwave integrated circuit (MMIC) technology at both microwave and millimeter‐wave frequencies. Other circuits use a novel substrate‐integrated waveguide (SIW) structure allowing integration of planar integrated circuit structure with waveguide structure. The performances of these six‐port circuits in digital receivers are reported in relation to signal modulation schemes, noise performance analysis calibration, and coding. Bit error rate simulation and measurement results obtained with demodulation algorithms are given for QPSK and QAM‐16 signals under a variety of operating conditions. Initial results show promising applications of six‐port technology for direct digital conversion demodulation reception, needed in future low‐cost SDR communication systems. Measurement and simulated demodulation results obtained with coding algorithms are also given.
Artificial Magnetic Conductor
Authors: Diaz Rodolfo E. , Clavijo Sergio A. 
Published: November 2024

AbstractThe artificial magnetic conductor (AMC) is a textured ground plane that presents a high impedance to incident waves and nearby horizontal antennas over a prescribed frequency range. In addition, it suppresses the propagation of both transverse electric (TE) and transverse magnetic (TM) surface waves, thus concentrating the radiation from a horizontal antenna into the upper half‐space. The resulting reduced backlobe and reduced mutual coupling to any other antennas on the same surface, combined with the high input impedance, make the AMC an ideal gain‐enhancing ground plane for ultrathin antennas. It is shown that these desirable features of are derived from the AMC's effective anisotropic magnetodielectric constitutive properties. Analysis and design approaches are given that enable the control of these properties according to the desired frequency and bandwidth of operation and the amount of surface‐wave suppression needed. Examples of the latest applications of AMC are given, as well as a brief history of its inception.
Magnetic Materials
Authors: van Dover Robert B. 
Published: November 2024

Abstract
Since the early part of the twentieth century, magnetic materials have been the subject of deep and broad research and development because of their economic and scientific importance, and much of our knowledge is mature. Nevertheless, startling discoveries continue to be made, such as the discovery of Nd–Fe–B permanent magnets and the “giant magneto‐resistance” effect in thin‐film multilayers.
Microstrip Lines
Authors: Ma Zhewang , Yamashita Eikichi , Atsuki Kazuhiko 
Published: November 2024

AbstractA microstrip line is a type of open planar transmission line that consists of a dielectric substrate medium with a ground plane on the lower side and a conducting strip on the upper side.Microstrip line is now one of the most widely used transmission lines for MICs. Active devices (diodes and transistors), lumped circuit elements (capacitors, resistors, inductors), dielectric resonators, and antennas can be easily incorporated into the circuit. Compared with the traditional bulky and heavy metallic waveguides and coaxial lines, the planar microstrip structures are smallsize, lightweight, easy for mass production, and inexpensive.
Microwave Mixers
Authors: Tahim R. S. 
Published: November 2024

AbstractThe frequency conversion function of a mixer plays a critical role in RF and microwave systems in determining their overall performance. For example, the quality of data transmission in the wireless communication systems and the identification of targets using radar and sensor systems are entirely dependent on the mixer performance in the receiver systems. The microwave/millimeter‐wave systems that operate at a number of frequency bands are susceptible to intermodulation frequency products generated in mixers. Spurious signals or distortion in mixers continues to be a problem in virtually all the RF and microwave systems. Therefore, mixers are frequently the dominant components in the receiver in establishing the system's distortion free performance. As a result, microwave and millimeter‐wave mixers have been the subject of continuous research and development for the past several decades and will continue to be the subject of future research in order to make the systems more efficient.
Microwave Receivers
Authors: Bao-Yen Tsui James 
Published: November 2024

Abstract
In this article, intercept microwave receivers will be the main subject because of their similarities in design goals. Intercept receivers are very useful in military applications. Used in electronic warfare (EW), they are often referred to as EW receivers.
This article includes description of a generic receiver, followed by a discussion of the important terminology and definitions used in receiver design.
Surface Acoustic Wave Filters
Authors: Hashimoto Ken-ya , Yamaguchi Masatsune 
Published: November 2024

AbstractCurrently, surface acoustic wave (SAW) filters are widely used in RF stages as well as IF stages of modern telecommunication systems. With successful research and development of SAW devices since the early 1960s, the growth of mobile phone markets has accelerated, with surprising advances in SAW device technologies since the early 1990s. This article discusses how the filtering function of SAW devices is realized using various SAW propagation phenomena, and reviews the performance of current commercial SAW filters. First, SAW transversal filters are discussed. Starting from a brief discussion of their fundamentals, we describe achievable performance, impact of the substrate selection and the most recent advances of this type of filter. Next, filters based on SAW resonators are discussed. After giving basic ideas of SAW resonators, it is shown how SAW resonator filters are composed and designed using SAW resonators.
Transverse Resonance Techniques
Authors: Sorrentino Roberto , Mongiardo Mauro 
Published: November 2024

Abstract
The transverse resonance technique in its various forms is presented and discussed, from the analytical solutions for inhomogeneously filled rectangular waveguides to the conventional approximate solution for transversely discontinuous waveguides (e.g., the ridge waveguide), to the generalized rigorous formulation for waveguide discontinuities and junctions.