bluuebunny/crossref_metadata_2025 huggingface dataset:
Influence of mixing method on the cement temperature‐mixing time history and doughing time of three acrylic cements for vertebroplasty
Authors: Baroud G. , Samara M. , Steffen T.
Published: December 2003

Acrylic cements are increasingly being used to augment osteoporotic vertebrae in a procedure called vertebroplasty. Two significant factors that may complicate the use of acrylic cements are: (a) short handling time, which may result in insufficient filling of the vertebra; and (b) exothermic setting (curing) behavior, which may result in thermal damage of the surrounding tissue. It has been previously reported1 that mixing the cement components under oscillation, as compared to manual mixing, increases the handling time. More specifically, it seems that oscillatory mixing slows down the cement polymerization process and, consequently, widens the time window during which cement is injectable. However, the effect of oscillatory mixing on the exothermic setting behavior of cement undergoing polymerization has not been examined. In this study, the exothermic setting behavior of three commercially available acrylic cements— Antibiotic Simplex®, DP‐Pour&trade, and Vertebroplastic™—were examined for both manual and oscillatory mixing methods. For each combination of cement and mixing method, the parameters that were measured were the exothermic setting curve (and hence the cement setting temperature and setting time) and the cement doughing time. It was found that oscillatory mixing had no significant effect on any of these parameters. Based on the results of this study, it can be concluded that, for the tested cements, the setting process is a reaction‐controlled process rather than a diffusion‐controlled one. Clinically, this implies that oscillatory mixing may be used to increase the working period for acrylic cements without increasing the risk of thermal damage to surrounding tissue. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 68B: 112–116, 2004
Influence of oscillatory mixing on the injectability of three acrylic and two calcium‐phosphate bone cements for vertebroplasty
Authors: Baroud G. , Matsushita C. , Samara M. , Beckman L. , Steffen T.
Published: December 2003

Injecting acrylic and, increasingly, calcium‐phosphate cements into the porous bone structure is an emerging procedure, referred to as vertebroplasty, for the augmentation of osteoporotic vertebrae. Despite the benefits of vertebroplasty, it has limitations. The limitations of interest in this study are the injectability of bone cements and their mixing variability (i.e., low reproducibility of resulting viscosity). The objective of this study is to investigate the effect of oscillatory versus manual mixing on cement viscosity and mixing variability. Five cements are tested: (a) Vertebroplastic™, (b) DP‐Pour™, (c) Antibiotic Simplex®, (d) chronOS Inject™, and (e) Biopex™. Compared to manual mixing, oscillatory mixing significantly decreased the mean viscosity and the mixing variability, which was inferred from the coefficient of variation. For example, under oscillatory mixing, the viscosity and the variability for Vertebroplastic decreased to one‐third of the corresponding values for manual mixing. Similar results were obtained for the other cements. The decrease in viscosity is attributed to the pseudo‐plastic behavior of bone cements. The decrease in the variability of cement viscosity was attributed to greater dispersive mixing of the cement components under oscillatory mixing. The decrease in viscosity eases the injection by reducing the pressure required. The decrease in the variability of cement viscosity increases reproducibility of the cement injection. Oscillatory mixing appears to have the potential to contribute to improving vertebroplasty. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 68B: 105–111, 2004
Are primary cultures realistic models of prostate cancer?
Authors: Peehl Donna M.
Published: December 2003

Primary cultures fill a unique niche among the repertoire of in vitro model systems available to investigate the biology of the normal and malignant human prostate. This review summarizes some of the properties of primary cultures, with special emphasis on two questions: are primary cultures from adenocarcinomas really comprised of cancer rather than normal cells, and do primary cultures faithfully retain characteristics of cells of origin? © 2003 Wiley‐Liss, Inc.
Cholesterol and prostate cancer
Authors: Freeman Michael R. , Solomon Keith R.
Published: December 2003

Cholesterol is a neutral lipid that accumulates in liquid‐ordered, detergent‐resistant membrane domains called lipid rafts. Lipid rafts serve as membrane platforms for signal transduction mechanisms that mediate cell growth, survival, and a variety of other processes relevant to cancer. A number of studies, going back many years, demonstrate that cholesterol accumulates in solid tumors and that cholesterol homeostasis breaks down in the prostate with aging and with the transition to the malignant state. This review summarizes the established links between cholesterol and prostate cancer (PCa), with a focus on how accumulation of cholesterol within the lipid raft component of the plasma membrane may stimulate signaling pathways that promote progression to hormone refractory disease. We propose that increases in cholesterol in prostate tumor cell membranes, resulting from increases in circulating levels or from dysregulation of endogenous synthesis, results in the coalescence of raft domains. This would have the effect of sequestering positive regulators of oncogenic signaling within rafts, while maintaining negative regulators in the liquid‐disordered membrane fraction. This approach toward examining the function of lipid rafts in prostate cancer cells may provide insight into the role of circulating cholesterol in malignant growth and on the potential relationship between diet and aggressive disease. Large‐scale characterization of proteins that localize to cholesterol‐rich domains may help unveil signaling networks and pathways that will lead to identification of new biomarkers for disease progression and potentially to novel targets for therapeutic intervention. © 2003 Wiley‐Liss, Inc.
Independent sets and 2‐factors in edge‐chromatic‐critical graphs
Authors: Grünewald Stefan , Steffen Eckhard
Published: December 2003

In 1968, Vizing made the following two conjectures for graphs which are critical with respect to the chromatic index: (1) every critical graph has a 2‐factor, and (2) every independent vertex set in a critical graph contains at most half of the vertices. We prove both conjectures for critical graphs with many edges, and determine upper bounds for the size of independent vertex sets in those graphs. © 2003 Wiley Periodicals, Inc. J Graph Theory 45: 113–118, 2004
Weakening arcs in tournaments
Authors: Hanson Denis , Moon John W.
Published: December 2003

A weakening arc of an irreducible tournament is an arc whose reversal creates a reducible tournament. We consider properties of such arcs and derive recurrence relations for enumerating strong tournaments with no such arcs, one or more such arcs, and exactly one such arc. We also give some asymptotic results on the numbers of such tournaments, among other things. © 2003 Wiley Periodicals, Inc. J Graph Theory 45: 142–162, 2004
Toughness, minimum degree, and spanning cubic subgraphs
Authors: Bauer D. , Niessen T. , Schmeichel E.
Published: December 2003

Degree conditions on the vertices of a t‐tough graph G (1 ≤ t < 3) are presented which ensure the existence of a spanning cubic subgraph in G. These conditions are best possible to within a small additive constant for every fixed rational t ∈[1,4/3)∪[2,8/3). © 2003 Wiley Periodicals, Inc. J Graph Theory 45: 119–141, 2004
s‐Regular cubic graphs as coverings of the complete bipartite graph K3,3
Authors: Feng Yan‐Quan , Kwak Jin Ho
Published: December 2003

A graph is s‐regular if its automorphism group acts freely and transitively on the set of s‐arcs. An infinite family of cubic 1‐regular graphs was constructed in [10], as cyclic coverings of the three‐dimensional Hypercube. In this paper, we classify the s‐regular cyclic coverings of the complete bipartite graph K3,3 for each ≥ 1 whose fibre‐preserving automorphism subgroups act arc‐transitively. As a result, a new infinite family of cubic 1‐regular graphs is constructed. © 2003 Wiley Periodicals, Inc. J Graph Theory 45: 101–112, 2004
Characterization of graphs with hall number 2
Authors: Eslahchi Changiz , Johnson Matthew
Published: December 2003

Hall's condition is a simple requirement that a graph G and list assignment L must satisfy if G is to have a proper L‐colouring. The Hall number of G is the smallest integer m such that whenever the lists on the vertices each has size at least m and Hall's condition is satisfied a proper L‐colouring exists. Hilton and P.D. Johnson introduced the parameter and showed that a graph has Hall number 1 if and only if every block is a clique. In this paper we give a forbidden‐induced‐subgraph characterization of graphs with Hall number 2. © 2003 Wiley Periodicals, Inc. J Graph Theory 45: 81–100, 2004
Isoform‐specific knockout of FE65 leads to impaired learning and memory
Authors: Wang Baiping , Hu Qubai , Hearn Mark G. , Shimizu Kimiko , Ware Carol B. , Liggitt Dennis H. , Jin Lee‐Way , Cool Bethany H. , Storm Daniel R. , Martin George M.
Published: December 2003

FE65 is a multimodular adapter protein that is expressed predominantly in brain. Its C‐terminal phosphotyrosine interaction domain (PID) binds to the intracellular tail of the β‐amyloid precursor protein (βPP), a protein of central importance to the pathogenesis of dementias of the Alzheimer type. To study the physiological functions of FE65, we generated a line of FE65 knockout mice via gene targeting. By Western analysis with a panel of FE65‐specific antibodies, we demonstrate that the 97‐kDa full‐length FE65 (p97) was ablated in the mutant mice, and that a previously undescribed FE65 isoform with apparent molecular mass of 60 kDa (p60) was expressed in both wild‐type and mutant mice. p60 had a truncated N‐terminus and was likely to be generated through alternative translation. Expressions of the two isoforms appeared to be brain region distinct and age dependent. The p97FE65–/– mice were viable and showed no obvious physical impairments or histopathological abnormalities. However, p97FE65–/– and p97FE65+/– mice exhibited poorer performances than wild‐type mice on a passive avoidance task when tested at 14 months (P < .05). p97FE65–/– mice at 14 months also exhibited impaired hidden‐platform acquisition (P < .05) and a severe reversal‐learning deficit (P < .002) but normal visual‐platform acquisition in the Morris water maze tests. Probe trials confirmed impairments in p97FE65–/– mice in relearning of new spatial information, suggesting a hippocampus‐dependent memory‐extinction deficit. Reduced secretion of Aβ peptides was observed in primary neuronal cultures of hybrids of p97FE65–/–/βPP transgenic (Tg2576) mice. These studies suggest an important and novel function of FE65 in learning and memory. © 2003 Wiley‐Liss, Inc.
Genomic structure, cochlear expression, and mutation screening of KCNK6, a candidate gene for DFNA4
Authors: Mhatre Anand N. , Li Jiang , Chen Arthur F. , Yost C. Spencer , Smith Richard J.H. , Kindler Christoph H. , Lalwani Anil K.
Published: December 2003

KCNK6 encodes a tandem pore domain potassium channel, TWIK‐2, that maps to chromosome 19. Both STS and linkage maps established KCNK6 as a positional candidate gene for DFNA4, a form of autosomal dominant nonsyndromic hereditary hearing loss. Identification and characterization of Kcnk6 expression within the mammalian cochlea established the gene as a functional candidate for DFNA4. Identification of Twik‐2 expression in the mouse cochlea was initially established via RT‐PCR assay of cochlear RNA. Subsequent immunoblot analysis of cochlear homogenate yielded a distinct 35‐kDa band corresponding to the calculated molecular weight of the mouse Twik‐2. Immunohistochemical studies localized Twik‐2 expression in the cochlea predominantly within the stria vascularis. This vascular tissue borders the cochlear duct and is a critical regulator of potassium concentration in the endolymph. Genomic structure of TWIK‐2 was subsequently determined and shown to consist of three coding exons with splice acceptor and donor sites in accordance with the consensus GT‐AG rule. Two separate DFNA4 families were screened for KCNK6 sequence alterations. No mutations were found, thus excluding TWIK‐2 as the DFNA4 candidate disease gene. Nevertheless, expression of Twik‐2 within the stria vascularis suggests a potential role for this protein as one of the terminal components of the potassium ion‐recycling pathway that contributes toward its reabsorption into the endolymph. © 2003 Wiley‐Liss, Inc.
Design of a modified meander‐type microstrip patch antenna in the 5‐GHZ band
Authors: Yoon Joong‐Han , Jeong Gyey‐Teak , Kang Moon‐Kyou , Lee Hwa Choon , Kwak Kyung‐Sup
Published: December 2003

In this paper, the characteristics of a modified meander‐type antenna for broadband impedance bandwidth are investigated in the 5‐GHz band. The design is based on a modified meander‐line width in a finite‐sized ground with coaxial SMA feeding. The modified meander‐type microstrip patch antenna is able to achieve an impedance bandwidth of about 1.0 GHz or 17.5% for a VSWR of less than 2. Radiation patterns are broad across the pass band. The gain is measured 7.3–9.5 dBi. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 40: 181–183, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11322
Determination of complex permittivity with neural networks and FDTD modeling
Authors: Eves E. Eugene , Kopyt Paweł , Yakovlev Vadim V.
Published: December 2003

A simple novel cavity‐independent method of determination of dielectric properties of arbitrarily shaped materials is presented. Complex permittivity is reconstructed using a neural networking procedure matching the measured and FDTD‐modeled frequency characteristics of the reflection coefficient. High accuracy and practical suitability are demonstrated through numerical testing and determination of dielectric properties of fresh and saline water at 915 MHz. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 40: 183–188, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11323
Combline filters using periodically loaded resonators
Authors: Shen Guohua , Budimir Djuradj
Published: December 2003

In this paper, we present a novel combline filter using periodically loaded resonators. A resonator with a periodic N‐disk mounted onto its inner conductor is used as novel combline resonator. A significantly improvedQfactor is achieved within the same volume of the conventional combline resonator. An example of a two‐pole combline filter is designed. Simulation and experimental results are presented. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 40: 189–191, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11324
Analysis and determination of coupling efficiency and misalignment tolerances between a laser diode and a conically lensed fiber
Authors: Faidz A. R. , Mishra V. N.
Published: December 2003

In this paper, we present a simple analysis, utilising the ABCD transformation matrix method, to analyze and determine the coupling efficiency and misalignment tolerances between a laser diode and a conically lensed fibre. The calculated and measured results, that is, the coupling efficiencies and transverse misalignments, were compared for microlenses etched at 20, 30, and 40 min. The calculated results agree well with the measured values. The angular misalignments are also calculated to determine their tolerances. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 40: 191–195, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11325
Edge instability elimination of GaAs/ALGaAs MQW avalanche transit time oscillators by p+ substrate
Authors: Meng C. C.
Published: December 2003

The p+ substrate plays an important role on the edge stability of p+n multiquantum well avalanche transit time devices. The p+n multiquantum well avalanche transit time devices on n+ substrate easily burn out along the device edge at low breakdown current. The same structure on p+ substrate can have the desired band diagram on device edge to eliminate edge burn‐out and CW operation is thus achieved at 100.3 GHz. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 40: 196–197, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11326
Development of EQM (engineering qualified model) local oscillator for KA‐band satellite transponder
Authors: Ryu Keun‐Kwan , Lee Moon‐Que , Yom In‐Bok , Lee Seong‐Pal
Published: December 2003

A low‐phase‐noise engineering qualified model (EQM) local oscillator (LO) has been developed for a Ka‐band satellite transponder. A voltage controlled dielectric resonator oscillator (VCDRO) is designed using a high‐impedance inverter coupled with a dielectric resonator to improve the phase‐noise performances. This EQM LO was made as an environmental experiment for space application and applied to a Ka‐band satellite transponder of the EQM level. The LO has harmonic suppression characteristics above 53 dBc and output power of 14.0 dBm ± 0.17 dB over the temperature range of −15–+65°C. The phase noise characteristics are exhibited as −102.33 dBc/Hz at 10 KHz and −114.33 dBc/Hz at 100‐KHz offset frequencies, respectively. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 40: 198–200, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11327
3D‐FDTD‐PML analysis of left‐handed metamaterials
Authors: Correia Davi , Jin Jian‐Ming
Published: December 2003

The increasing interest in negative‐index metamaterials requires a formulation capable of a full analysis of wave propagation in such materials. Since two‐dimensional (2D) problems have been largely explored in the literature, the natural step is a three‐dimensional (3D) formulation of a metamaterial. In this work, we present a simulation of a left‐handed metamaterial using the finite‐difference time‐domain (FDTD) method in conjunction with perfectly matched layers (PMLs). First, we develop a PML to work with a Drude medium model. Then we apply our formulation to a 3D domain and compare our results with 2D problems. Finally, we simulate a dipole on the top of a metamaterial slab, presenting the field distribution in three different directions. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 40: 201–205, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11328
Proposed OCDMA encoders and decoders based on silica‐on‐silicon integrated optics
Authors: Zhang Jian‐Guo , Wen Yumei , Li Ping
Published: December 2003

A new scheme is proposed for fixed and tunable optical code‐division multiple‐access (OCDMA) encoders and decoders, which can be implemented by using silica‐on‐silicon integrated optics to achieve both low loss and compactness. The feasible architectures for OCDMA encoder/decoder are discussed, and the conceptual design is also presented. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 40: 205–209, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11329
Magnetic wall from slotted screens and a ground plane
Authors: Sauviac B. , Simovski C. R.
Published: December 2003

In this work we study the potential to decrease the resonant frequency of a high‐impedance surface (HIS) formed by a periodically slotted screen and a metal ground plane for the case in which the structure's horizontal period and vertical thickness are fixed. The slotted screens, whose slits are shaped as Jerusalem crosses (JCs) have been studied in the literature as uniplanar photonic band‐gap (PBG) structures for surface waves and as the HIS (when the ground plane is added). We modify the geometry of the slit for the fixed period and show that this leads to a certain decrease in the resonant frequency, which means that the proposed structure can be used as a magnetic wall at lower frequencies. Also, we show that our modification allows the structure thickness for a fixed grid period and resonant frequency to decrease by 30%. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 40: 209–211, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11330
Improved predistorter for GaAs FET power amplifier
Authors: Lo Wai Keung , Chan Wing Shing , Li Chung Wai
Published: December 2003

Linearization of the gate‐source capacitance in a GaAs FET, realized by using a varactor diode, tends to offer limited improvement. This paper presents a method to allow more flexibility due to the addition of a resistor in series with the linearizing varactor diode. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 40: 211–213, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11331
Using tunable coherent reflectometry to optimize ER‐doped L‐band amplifiers
Authors: Costa e Silva M. B. , von der Weid J. P. , Margulis W.
Published: December 2003

The use of tunable coherent reflectometry is an efficient technique to characterize doped‐fiber amplifiers. This technique is used to perform tests with EDF in the L band, thus permitting the determination of optimum length. The results confirm that some known structures increase the small‐signal gain by adding a seed signal in a single pump‐fiber amplifier. The analyzed fiber presented 23.5‐dB flat gain from 1570 to 1600 nm, which was obtained by introducing a flat ∼100% Bragg grating covering the C‐band before the Er‐doped fiber in a single pump/pass configuration. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 40: 213–216, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11332
Characterization and fabrication of InGaAsP/InP deep‐etched micro‐waveguides
Authors: Beaurain A. , Dupont S. , Li H. W. , Vilcot J. P. , Legrand C. , Harari J. , Constant M. , Decoster D.
Published: December 2003

InGaAsP/InP micro‐waveguides are fabricated by a deep (>3 μm) Reactive Ion Etching. The devices losses are measured by the Fabry–Perot technique for guide width contained between 10 μm and 0.5 μm. The measured losses range from 2 dB/mm to 14 dB/mm. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 40: 216–218, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11333
Ku‐band printed quadrifilar helical antenna with integrated feeding network
Authors: Letestu Y. , Sharaiha A.
Published: December 2003

This paper presents an integrally formed printed quadrifilar helical antenna (PQHA) and balun‐fed network combination for satellite communication systems in Ku‐band. At this frequency band, we demonstrate that the antenna can be simply realized and will demonstrate good radiation characteristics. Analysis of this antenna is achieved by the FDTD method. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 40: 219–221, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11334
A new reflection coefficient modulus method for broadband matching problems
Authors: Su Tao , Liang Changhong , Shi Yan
Published: December 2003

There are many engineering problems currently in practice in which the phase of reflection coefficient is unknown or varies. This paper presents a reflection coefficient theory for lossless broadband matching networks and describes its limitations and band inequalities. An example matching problem is given in the end of the paper. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 40: 221–224, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11335
Physical modeling of a novel barrier‐enhanced quantum‐well photodetector device for optical receivers
Authors: Tait Gregory B. , Nabet Bahram
Published: December 2003

A novel barrier‐enhanced InGaAs/InAlAs quantum‐well MSM photodetector with recessed electrodes is shown to be a promising high‐sensitivity, high‐speed device for optical receivers. Carrier transport simulations indicate very low, dark current at 10−6 A/m and electrical 3‐dB bandwidth at 50 GHz for a 1‐μm finger‐gap device. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 40: 224–227, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11336
Reducing the effects of ambient noise light in an indoor optical wireless system using polarizers
Authors: Lee Seong‐Ho
Published: December 2003

Two linear orthogonal polarizers are used to reduce the effects of ambient noise light in an indoor optical wireless receiver. Using a differential detector coupled with orthogonal polarizers, the interference arising from a fluorescent lamp driven by electronic ballasts is reduced by about 15 dB. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 40: 228–231, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11337
Three transmission‐line transformers for phase retrieval from scalar reflection coefficients
Authors: Attiya Ahmed M.
Published: December 2003

In this paper, a new approach to obtain the phase angle of an unknown complex load using scalar reflection coefficients is presented. This approach is based on measuring the scalar reflection coefficient using three different transmission‐line transformers. The relation between the two scalar reflection coefficients is presented as a nonlinear equation of the unknown phase angle. The value of the unknown phase angle represents a common root of these nonlinear phase equations. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 40: 231–235, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11338
Optimization of the current integration method for a front‐fed parabolic reflector antenna
Authors: D'Agostino F. , Gennarelli C. , Riccio G. , Savarese C.
Published: December 2003

This work centers on an optimization of the current integration method for determining the field radiated by a centered parabolic reflector fed at its focus. A nonredundant sampling representation of the physical optics (PO) current, induced on the main reflector by the electromagnetic field radiated from the primary field source, and an optimal sampling interpolation algorithm are developed to this end. Such an approach allows one to reduce the number of points where the knowledge of the current is required, so that the computation time decreases remarkably when the evaluation of the field radiated from the feed is burdensome. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 40: 235–239, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11339
Optimization of a small to‐can package electrical design for SFF/SFP optical transceiver modules
Authors: Lee Sang‐Hoon , Cho Yong‐Sang , Koo Bon‐Jo , Han Sang‐Kook
Published: December 2003

In this paper, we present an optimum TO‐38 package design for SFF/SFP optical transceiver modules in order to improve the 3‐dB bandwidth. The frequency response of the TO‐38 package is measured and compared to simulation where the 3‐dB‐bandwidth was 3.5 GHz. For a higher operating bandwidth (>15 GHz), new optimized physical geometries for the TO‐can package, such as bonding wires, leads, and material, are suggested. The optimal result of simulation shows that this TO‐can package can be used at a higher‐bit‐rate optical module of 10 Gb/s. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 40: 239–242, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11340
Low‐temperature solutions for UMTS base‐station receivers using superconducting and low‐noise active filtering techniques
Authors: Quintanel Sébastien , Billonnet Laurent , Jarry Bernard , Marcilhac Bruno , Mage Jean‐Claude
Published: December 2003

The different steps of a cryogenic low‐noise amplifier design are presented. The noise parameters of a HEMT transistor are measured and used to determinate the Pospieszalski noise model 1. This noise model is used for the design of a one‐stage LNA for which the matching circuits are realised with superconductor material for optimal noise performances. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 40: 242–245, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11341
Low backscattered dual‐polarised metallo‐dielectric structure based on Sierpinski carpet
Authors: Chandran Anupam R. , Mathew Thomaskutty , Aanandan C. K. , Mohanan P. , Vasudevan K.
Published: December 2003

A novel technique for backscattering reduction for both TE and TM polarisations, employing a metallo‐dielectric structure based on Sierpinski carpet fractal geometry, is reported. A reduction in backscattered power of ∼30 dB is obtained for normal incidence in the X‐band for the structure using the third iterated stage of the fractal geometry. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 40: 246–248, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11342
A compact novel slot‐loaded dual‐frequency H‐shaped antenna
Authors: Qi Dongsheng , Li Binhong , Zhang Yabin , Liu Haitao
Published: December 2003

A novel compact single‐layer dual‐frequency microstrip antenna which uses an H‐shaped geometry with two U‐shaped slots embedded near the radiation edges, is presented. By changing the design parameters, the lower and higher resonant frequencies can be controlled easily, and a range of frequency ratios (1.716–2.363) can be obtained in this design. For the two operating frequencies of the proposed antenna, the same polarization planes and broadside radiation patterns are achieved. Compared to the regular dual‐frequency patch antenna, this antenna can realize a significant size reduction. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 40: 248–250, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11343
An omnidirectional ADE reflector antenna
Authors: Bergmann José R. , Moreira Fernando J. S.
Published: December 2003

In this work, an axially‐displaced‐ellipse (ADE) dual‐reflector antenna for the achievement of an omnidirectional coverage is proposed. Its geometry is briefly presented and some relevant features are compared against previously suggested reflector antennas, designed for the same purpose. The present ADE configuration is capable of yielding the desired aperture illumination with relatively smaller reflector dimensions, thus providing a compact arrangement suited for use at base stations of point‐to‐multi‐point radio links. Numerical simulations are presented to illustrate the usefulness and advantages of the proposed reflector antenna. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 40: 250–254, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11344
Microwave monolithic phase shifter for optical transmission at 40 Gb/s
Authors: Bosse S. , Billonnet L. , Jarry B. , Jallageas H. , Blache F. , Mouzannar W.
Published: December 2003

This paper deals with a design technique for an integrated planar phase shifter on GaAs substrate at millimetre‐wave frequencies for optical transmission applications at 40 Gb/s. We numerically show how an amplifier can be adequately associated with a nonconstant magnitude phase shifter to avoid a magnitude modulation of the optical signal when tuning the phase shift. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 40: 254–258, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11345
Improvement of MMW irradiation uniformity in culture dishes for experiments on MMW biological effects
Authors: Zhao Jianxun
Published: December 2003

Methods to improve the uniformity of the millimeter‐wave (MMW) dose distribution on the cell monolayer in culture dishes are tested via experiments on MMW biological effects at the cellular level. Calculated using the finite‐difference time‐domain (FDTD) numerical technique, the MMW dose distribution, represented by the distribution of the MMW power density (PD) irradiated into cells and that of the MMW power absorption density (PAD) of cells, is analyzed for three culture dishes of different configurations. Results indicate that enlarging the culture dish diameter and reducing its bottom thickness are two effective methods to improve the MMW irradiation uniformity. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 40: 258–261, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11346
Offset stacked patches behavior in an array
Authors: Rajo‐Iglesias Eva , Vázquez‐Roy José‐Luis , Inclán‐Sánchez Luis , Segovia‐Vargas Daniel , González‐Posadas Vicente , Martín‐Pascual Carlos
Published: December 2003

In this paper, an experimental study of the behavior of offset stacked patches in an array is presented. The goal of this work is to prove that these asymmetrical patches are useful for improving E‐plane radiation pattern symmetry in stacked‐patch arrays. To this aim, an array of stacked patches whose upper layer can be moved along the E‐plane is manufactured. Measurements show the advantages of such arrays. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 40: 262–265, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11347
Mutual coupling effects between transmit and receive antennas mounted on rectangular structure using FDTD algorithm
Authors: Choi Dong‐Hyuk , Cho Young‐Il , Park Seong‐Ook , Lee Joo‐Gwang
Published: December 2003

This paper presents the radiation patterns of the monopole antenna mounted on the rectangular shaped structure and the coupling problem between transmit (Tx) and receiver (Rx) antennas obtained by using the FDTD method. A comparison of FDTD calculated results with the exact solution for cylindrical structure validates the accuracy of the algorithm. Using the developed FDTD code, the power radiated from the Tx port influences the Rx port at the nearby working frequency of 2 GHz. The magnitude of coupling effects in terms of scattering parameters has the highest value of about −40 dB within the 2–3.5‐GHz frequency range. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 40: 265–268, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11348
Negative ion electrospray mass spectrometry of aminomethylphosphonic acid and glyphosate: elucidation of fragmentation mechanisms by multistage mass spectrometry incorporating in‐source deuterium labelling
Authors: Goodwin Lee , Startin James R. , Goodall David M. , Keely Brendan J.
Published: December 2003

Glyphosate and its main metabolite, aminomethylphosphonic acid, introduced by direct infusion in 2H2O, appear in negative ion electrospray mass spectrometry (ES‐MS) as triply deuteriated [MH]− ions. Sites of deuterium residence and loss were established using the multistage (MSn) capabilites of an ion trap mass spectrometer to assist in the determination of fragmentation mechanisms. The study reveals specific mechanisms, common to each analyte, such as those involving a five‐membered transition state between the amine and phosphonate group, as well as analyte specific transitions. Copyright © 2003 John Wiley & Sons, Ltd.
Thermodynamic study of some chromium‐containing gaseous molecules by high‐temperature mass spectrometry
Authors: Lopatin S. I. , Shugurov S. M. , Semenov G. A.
Published: December 2003

A number of gaseous oxyacid salts have been identified by Knudsen effusion mass spectrometry, while vaporizing Cr2O3 and mixtures of Cr2O3+Nb2O5, Cr2O3+Ta2O5, Cr2O3+BaO, and Cr2O3+Mg2P2O7 from molybdenum and tungsten cells. The stabilities of the gaseous molecules CrMoO3, CrMoO4, CrMoO5, CrWO3, CrWO4, CrWO5, CrNbO3, CrTaO3, CrPO2, CrPO3, BaCrO2 and BaCrO3 were deduced from the measurements. The thermodynamic properties of this gaseous chromium‐containing species are summarized. Prediction is tentatively made of the stability of as‐yet unstudied gaseous molecules. Copyright © 2003 John Wiley & Sons, Ltd.
A study of ion suppression effects in electrospray ionization from mobile phase additives and solid‐phase extracts
Authors: Mallet Claude R. , Lu Ziling , Mazzeo Jeff R.
Published: December 2003

Since the wide adoption of liquid chromatography/tandem mass spectrometry (LC/MS/MS), the ion suppression/enhancement phenomenon is the latest barrier to high‐throughput analysis. This consequence of a nonoptimized analytical method can lead to adverse effects during quantitation (i.e. poor accuracy and precision). Previous papers have reported that ion suppression is a direct result of endogenous material present in biological samples. However, in the case of a solid‐phase liquid chromatography/tandem mass spectrometry (SPE/LC/MS/MS) system, the measured result is the combination of several operating conditions and parameters. Little has been done to effectively monitor and/or choose optimized conditions for the complete sequence of extraction, clean up, separation and analysis. This paper describes a simple setup for quantification of ion suppression/enhancement. Several mobile phase additives, ion‐pairing agents and SPE extracts were measured and compared against a standard reference. The results demonstrated that a clean up of plasma extracts based on ion exchange leads to minimal ion suppression/enhancement for the compounds that were investigated. Copyright © 2003 John Wiley & Sons, Ltd.
Electron and electrospray ionization mass spectrometry in the characterization of some 1‐allyl‐3‐phenylaziridines
Authors: Begala Michela , Forni Arrigo , Delogu Giovanna , Podda Gianni , Prati Fabio , Torre Giovanni , Tubaro Michela
Published: December 2003

A series of cis‐ and trans‐isomeric aziridines has been studied under electron impact (EI) and electrospray ionization (ESI) conditions. The fragmentation patterns of the examined compounds have been elucidated by means of sequential product ion fragmentation experiments (MSn) performed using an ion trap mass spectrometer. Particular attention has been paid to isomer characterization in these precursors of azetidinones, that in turn are precursors of new β‐lactam antibiotics. Copyright © 2003 John Wiley & Sons, Ltd.
Study of peptides containing modified lysine residues by tandem mass spectrometry: precursor ion scanning of hexanal‐modified peptides
Authors: Fenaille François , Tabet Jean‐Claude , Guy Philippe A.
Published: December 2003

Upon hexanal‐modification in the presence of NaCNBH3, the oxidized B chain of insulin becomes mono‐ and further dialkylated on both the N‐terminal and Lys29 residues. A pseudo‐MS3 study was performed with a triple‐quadrupole mass spectrometer on the different modified lysine‐containing species to gain further insights into the characteristic fragmentation pattern. These fragmentations, in good agreement with true MS3 measurements obtained using an ion trap mass spectrometer, highlighted characteristic monoalkylated lysine (immonium—NH3) and protonated modified caprolactam ions at m/z 168 and 213, respectively. In contrast, no fragment ion derived from a modified lysine residue (immonium or caprolactam) was observed when dialkylation occurs on Lys29. However, a fragment ion corresponding to a protonated dihexylamine was observed at m/z 186. This loss, characteristic of dialkylated lysine fragmentation, was also observed upon dialkylation of Nα‐acetyllysine with either hexanal or pentanal. On the other hand, acetylation and malondialdehyde‐modification of the Nα‐acetyllysine side chain led mainly to the corresponding modified (immonium—NH3) fragment ions at m/z 126 and 138, respectively. Finally, it was demonstrated that precursor ion scanning for both m/z 168 and 213 ions led to specific and sensitive identification of peptides containing hexanal‐modified lysine residues within an unfractionated tryptic digest of hexanal‐modified apomyoglobin. Thus, Lys42, Lys45, Lys62, Lys63, Lys77, Lys87, Lys96, Lys98, Lys145 and Lys147 were found to be modified upon reaction with hexanal. Copyright © 2003 John Wiley & Sons, Ltd.
Analysis of 21‐deoxycortisol, a marker of congenital adrenal hyperplasia, in blood by atmospheric pressure chemical ionization and electrospray ionization using multiple reaction monitoring
Authors: Cristoni Simone , Cuccato Debora , Sciannamblo Mariateresa , Bernardi Luigi Rossi , Biunno Ida , Gerthoux Piermario , Russo Gianni , Weber Giovanna , Mora Stefano
Published: December 2003

Congenital adrenal hyperplasia (CAH) is an autosomal recessive disorder mainly caused by 21‐hydroxylase deficit (21‐OHD). Deletions or mutations of the CYP21 gene induce the impairment of glucocorticoid and mineralcorticoid synthesis. 17‐Hydroxyprogesterone (17‐OHP) is the hormonal marker in patients, but not in the heterozygous subjects. Excess 17‐OHP is hydroxylated into 21‐deoxycortisol (21‐DF), and therefore 21‐DF can be used as a specific marker for diagnosis of heterozygous individuals. We report an analytical method for analysis of 21‐DF in blood samples using electrospray (ESI) and atmospheric pressure chemical ionization (APCI), showing that ESI is very sensitive for the analysis of this marker molecule. The multiple reaction monitoring (MRM) approach was used to increase the specificity and the sensitivity of the method. Copyright © 2003 John Wiley & Sons, Ltd.
Sensitive high‐performance liquid chromatography/mass spectrometry method for determination of steviol in rat plasma
Authors: Wang L. Z. , Goh B. C. , Fan L. , Lee H. S.
Published: December 2003

The main toxicological concern of stevioside, a highly potent sweetener from S. rebaudiana, is its main metabolite, steviol. To determine very low levels of steviol in in vivo experiments, a sensitive liquid chromatography/atmospheric pressure chemical ionization mass spectrometry (LC/APCI‐MS) method was developed for quantifying steviol in rat plasma after oral administration of a single dose of stevioside (0.5 g/kg). The sample preparation uses liquid‐liquid extraction with tert‐butyl methyl ether in an acidic environment. The retention time of steviol was 10.5 min. The assay was linear over the range 2–1000 ng/mL with a lower limit of detection of 1 ng/mL. The intra‐ and inter‐day precision were <5 and <7%, respectively, and the accuracy was in the range 95–108%. The steviol concentration profile in rat plasma was determined. Copyright © 2003 John Wiley & Sons, Ltd.
N‐t‐butyliodoacetamide and iodoacetanilide: two new cysteine alkylating reagents for relative quantitation of proteins
Authors: Pasquarello Carla , Sanchez Jean‐Charles , Hochstrasser Denis F. , Corthals Garry L.
Published: December 2003

The synthesis and application of two new alkylating reagents, N‐tert‐butyl‐2‐iodoacetamide (N‐t‐butyliodoacetamide) and 2‐iodo‐N‐phenylacetamide (iodoacetanilide), are described. N‐t‐Butyliodoacetamide and iodoacetanilide were synthesised to purity in their d0‐light and in their respective d9‐ and d5‐heavy forms. The newly synthesised reagents are covalently bound to peptides containing cysteines via an alkylation reaction. The mass differences of 5 and 9 Da avoid possible problems of overlapping isotope distribution. For each alkylated cysteine a peptide mass increases, respectively, by a multiple of 113 and 133 Da for the d0‐light form of N‐t‐butyliodoacetamide and iodoacetanilide. These reagents can therefore replace common alkylating reagents in existing proteomics‐based applications. Alkylated peptides increase in mass in the same mass range as amino acids and remain suitable for tandem mass spectrometry (MS/MS) data acquisition and analysis. The compounds are simple to use and derivatisation is based on widely applied alkylating procedures. Preliminary results show that these reagents can be applied for both protein quantitation and identification by peptide mass finger printing and/or MS/MS techniques. Using these chemicals and the suggested workflow enables the quantitative analysis of the whole protein sample and realises access to peptides that may contain potential post‐translational modifications. Other approaches that incorporate a matrix‐assisted laser desorption/ionisation (MALDI) interface prior to MS can take advantage of these chemicals, such as the molecular scanner. Copyright © 2003 John Wiley & Sons, Ltd.
Mass spectrometric studies of some novel sulfonamides
Authors: Haskins Charlotte M. , Haskins Neville J. , Knight David W.
Published: December 2003

A recent paper described the overall 5‐endo cyclisation of homoallylic sulfonamides to give pyrrolidines. This reaction was also used to prepare polycyclic systems. Mass spectrometric analysis using classical electron ionisation spectra and accurate mass measurement played a vital role in confirming the proposed structures for the products. These materials were not amenable to newer mass spectrometric methods and this study shows the continuing importance of older techniques. Copyright © 2003 John Wiley & Sons, Ltd.
Improved procedures for N‐terminal sulfonation of peptides for matrix‐assisted laser desorption/ionization post‐source decay peptide sequencing
Authors: Wang Dongxia , Kalb Suzanne R. , Cotter Robert J.
Published: December 2003

Post source decay (PSD) analysis of precursor ions generated from matrix‐assisted laser desorption/ionization time‐of‐flight (MALDI‐TOF) mass spectrometry is a powerful tool for amino acid sequencing and primary structure analysis of proteins. N‐Terminal sulfonation has become an effective derivatization strategy in facilitating de novo peptide sequencing by the formation of predominate y‐type ion series in MALDI PSD spectra. Recently, an effective and inexpensive N‐terminal derivatization method has been reported using 4‐sulfophenyl isothiocyanate (SPITC) as the derivatization reagent (J. Mass. Spectrom. 2003; 38: 373–377). In this paper, we report an improvement in the derivatization procedure with this reagent that involves replacing an organic co‐reagent with other chemicals and eliminating the use of organic solvent. The method is demonstrated on a model peptide and on tryptic digests of two proteins. The results indicate that the improved sulfonation reaction can be implemented with high efficiency under aqueous conditions and that the sensitivity of mass detection can be increased considerably. Copyright © 2003 John Wiley & Sons, Ltd.
Regioselective syntheses, structural characterization, and electron ionization mass spectrometric behavior of regioisomeric 2,3‐disubstituted 2‐imino‐1,3‐thiazolidin‐4‐ones
Authors: Klika Karel D. , Valtamo Pauliina , Janovec Ladislav , Suchár Gejza , Kristian Pavol , Imrich Ján , Kivelä Henri , Alföldi Juraj , Pihlaja Kalevi
Published: December 2003

The regioselective syntheses of 3‐alkyl(aryl)‐2‐(anthracen‐9′‐ylimino)‐1,3‐thiazolidin‐4‐ones (2) and 2‐alkyl(aryl)imino‐3‐(anthracen‐9′‐yl)‐1,3‐thiazolidin‐4‐ones (3) from N‐(anthracen‐9‐yl)‐N′‐alkyl(aryl)thioureas were accomplished effectively using methyl bromoacetate and bromoacetyl bromide, respectively. Detailed structural characteristics were confirmed mainly by NMR techniques. The mass spectrometric behavior of the resulting sets of compounds of known structures was shown to be characteristic for each set. Some interesting fragmentation pathways involving the transfer and rearrangements of various moieties were also revealed, as well as regioisomerization for particular substituent‐specific fragmentations. Copyright © 2003 John Wiley & Sons, Ltd.