bluuebunny/crossref_metadata_2025_split huggingface dataset:
Three transmission‐line transformers for phase retrieval from scalar reflection coefficients
Authors: Attiya Ahmed M. 
Published: December 2003

AbstractIn 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

AbstractThis 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

AbstractIn 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

AbstractThe 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

AbstractA 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

AbstractA 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

AbstractIn 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

AbstractThis 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

AbstractMethods 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

AbstractIn 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

AbstractThis 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

AbstractGlyphosate 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

AbstractA 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

AbstractSince 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

AbstractA 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

AbstractUpon 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

AbstractCongenital 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

AbstractThe 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

AbstractThe 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

AbstractA 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

AbstractPost 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

AbstractThe 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.