bluuebunny/crossref_metadata_2025 huggingface dataset:
Fast gas chromatography–negative‐ion chemical ionization mass spectrometry with microscale volume sample preparation for the determination of benzodiazepines and α‐hydroxy metabolites, zaleplon and zopiclone in whole blood
Authors: Gunnar Teemu , Ariniemi Kari , Lillsunde Pirjo
Published: April 2006

Fast gas chromatography/negative‐ion chemical ionization mass spectrometric (GC/NICI‐MS) assay combined with rapid and nonlaborious sample preparation is presented for the simultaneous determination of benzodiazepines and α‐hydroxy metabolites, zaleplon and zopiclone in whole blood. The compounds were extracted from 100 µl of whole blood by simultaneous multitube, microscale liquid‐liquid extraction (LLE) and derivatized by N‐methyl‐N‐(tert‐butyldimethylsilyl)trifluoroacetamide (MTBSTFA), without the need for the time‐consuming concentration stage. In the analytical separation, various parameters of fast GC/NICI‐MS were applied, e.g. the use of hydrogen as a GC carrier gas, a high carrier gas velocity, a small film thickness of the analytical column, fast MS data acquisition, fast temperature ramping, and high initial and final temperatures of GC column. Sensitive identification, screening and quantitation of 18 compounds of interest were achieved in chromatographic separation in only 4.40 min. Accurate and reproducible results were obtained by using five different and carefully selected deuterated analogues on the basis of the chemical properties of the target analytes. Nevertheless, for α‐OH‐midazolam, and for bromazepam and flunitrazepam at low concentrations, the results can be considered only semiquantitative on the basis of the validation data. The extraction efficiencies ranged from 74.3 to 105.7% and the limits of quantitation (LOQ) from 1 to 100 ng ml−1. Rapid sample preparation and fast chromatographic separation allowed cost‐efficient, reliable and high sample‐throughput analyses with a low amount of manual work. The method was fully validated and accredited according to EN ISO/IEC 17025 standards and is applicable for sensitive, reliable and quantitative determination of benzodiazepines, zaleplon and zopiclone, e.g. in clinical and forensic toxicology. Copyright © 2006 John Wiley & Sons, Ltd.
Non‐enzymatic model glycation reactions — a comprehensive study of the reactivity of a modified arginine with aldehydic and diketonic dicarbonyl compounds by electrospray mass spectrometry
Authors: Saraiva Marco A. , Borges Carlos M. , Florêncio M. Helena
Published: April 2006

Non‐enzymatic glycation (Maillard reaction) of long‐lived proteins is a major contributor to the pathology of diabetes, and possibly aging and Alzheimer's disease. Among the amino residues in proteins arginine plays an important role, and its modification by sugar moieties generates the so‐called advanced glycation end products (AGEs). Moreover, α‐dicarbonyl compounds have been found as the main participants in those modifications.

Four α‐dicarbonyl compounds, aldehydic and ketonic, were reacted with the modified amino acid Nα ‐acetyl‐L‐arginine (AcArg), in an attempt to establish structure/activity relationships for the reactivity of α‐dicarbonyls with the amine compound. Electrospray ionization mass spectrometry (ESI‐MS), combined with tandem mass spectrometry (MS/MS), was used to identify and characterize reagents, intermediates and reaction products. The fragmentation patterns of precursor ions showed similarities in all reaction systems studied, in which fragmentation of the amino acid residue prevails, especially for the dehydrated and/or multiple dehydrated precursor ions. For the non‐hydrated ion species, fragmentation of the arginyl guanidino group was mainly observed. Specific information regarding the nature of the ions formed, in which the dicarbonyl electrophile character played an important role, was obtained. As an example, singly and doubly hydrated acetyl‐argpyrimidine ions were detected for the methylglyoxal reaction only. For symmetrical dicarbonyls, glyoxal and diacetyl, the importance of steric contributions with respect to the energetic ones is discussed. Furthermore, the dehydrated acetyl‐tetrahydropyrimidine ions for methylglyoxal and phenylglyoxal reactions revealed fragment ion compositions including the protonated molecules of acetyl‐argpyrimidine, ‐hydroimidazolone and ‐5‐methylimidazolone. An explanation for the acetyl‐argpyrimidine formation from the acetyl‐hydroimidazolone formation reaction is proposed. Aspects such as the amount of acetyl‐hydroimidazolone formed, the response of the hydration equilibria of the dicarbonyl forms to the new unhydrated dicarbonyls introduced by the reversal of the acetyl‐hydroimidazolone formation reaction and the stability of the dicarbonyl intermediate involved in the acetyl‐argpyrimidine formation are proposed, as being responsible to control the formation of acetyl‐argpyrimidine. Copyright © 2006 John Wiley & Sons, Ltd.
Reducing runoff by managing crop location at the catchment level, considering agronomic constraints at farm level
Authors: Joannon A. , Souchère V. , Martin P. , Papy F.
Published: April 2006

Runoff and erosion cause frequent damage through muddy floods in the loess belt of Northern Europe. One possibility for reducing damage is to lower runoff on agricultural land by spatially alternating different crops at the catchment level. But crop location results from decisions taken at the farm level. This study aimed to assess the existing leeway to modify crop location in the farms of a catchment, in order to reduce runoff at the catchment's outlet. The case study was the Bourville catchment (1086 ha), cultivated by 28 farmers and located in Pays de Caux, France. First, crop location rules in the 14 main farms of the catchment were analysed on the basis of surveys carried out with farmers, distinguishing spatial constraints from temporal ones. These rules made it possible to simulate crop location on each farm territory for the 2001–2002 crop year. Each field of the catchment was classified depending on whether one or several crops could be sown, taking into account both field history and farmer decision rules. Then two extreme scenarios of crop location in the Bourville catchment were built. Runoff simulation at the outlet with the STREAM model showed that runoff could be reduced while sticking to current farmer decision rules in terms of crop location. Depending on rainfall event characteristics, runoff reduction varied between 13·5 per cent and 4·5 per cent. Copyright © 2006 John Wiley & Sons, Ltd.
Thermophysical Properties and Molecular Relaxations in Cured Epoxy Resin + PEO Blends: Observations on Factors Controlling Miscibility
Authors: Kalogeras Ioannis M. , Vassilikou‐Dova Aglaia , Christakis Iraklis , Pietkiewicz Dorota , Brostow Witold
Published: April 2006

Summary: Thermophysical properties and molecular relaxations in aromatic amine‐cured diglycidyl ether of bisphenol‐A (DGEBA) epoxy oligomer and poly(ethylene oxide) (PEO) mixtures were determined by DSC and dielectric techniques (TSC, DRS). The binary blends were judged to be fully miscible in the amorphous state (wPEO < 40 wt.‐%), as evidenced by the single composition‐dependent glass transition temperatures Tgs. In the amorphous blends, negative deviations of dielectric/thermal Tg‐estimates from the linear mixing rule or the behavior predicted by the Fox equation reveal weaker intermolecular interactions, compared to strong self‐association of hydroxyls in the cured thermoset. Morphological changes in PEO‐rich blends (wPEO ≥ 40 wt.‐%) are in accordance with their complicated interface structure, previously reported to consist of amorphous PEO regions, branched epoxy resin chains and an imperfect epoxy resin network located between PEO lamellae. In these blends, PEO crystallites exert steric hindrances in the amorphous regions, causing strong Tg upshifts. Changes in the relaxation dynamics of glyceryl segments (e.g., in the activation energy barrier and relaxation strength) are in accordance with the idea that the close matching between the molecular polarities of PEO, epoxy resin and the cure agent significantly contributes to the observed miscibility.

Plots of transition temperatures as function of blend composition.

magnified image

Plots of transition temperatures as function of blend composition.
From the Micro‐ to the Macro‐: Managing the Conservation of the Warship, Vasa
Authors: Hocker Emma
Published: April 2006

Sweden's famous warship, Vasa, sank on her maiden voyage in August 1628, and remained on the bottom of Stockholm harbour for 333 years. Raised in 1961, she became the first large‐scale wooden object to be treated with polyethylene glycol (PEG). In the summer of 2000 a number of acidic salt precipitations were noticed on the surface of the ship and on wooden artefacts in the storerooms. An international research project has been established to look into the causes of this problem and suggest possible re‐treatments. Meanwhile projects are underway to monitor movements in the ship, to build a better support system, and to replace the thousands of iron bolts holding the structure together, while a sophisticated new climate system has recently been installed in the museum.
The Effects of UV Laser Radiation as Sterilizer for Cultural Heritage
Authors: Belloni Fabio , Nassisi Vincenzo , Alifano Pietro , Monaco Caterina , Panzanaro Santina
Published: April 2006

This work reports on a novel sterilization technique for bacteria which may be involved in deterioration of cellulose‐based antiquities (paper, textile and wood). The bacterium we processed, a Nonomuraea sp. strain, was a mycelial microorganism belonging to the Actinomycetes group. This group includes many microorganisms that are able to attack cellulose and/or lignin. Escherichia coli was used as a reference microorganism. The UV source used as sterilizer was an excimer laser operating at 308 nm, 1 Hz. We demonstrated that, under different experimental conditions, the sterilization process was effective just after few seconds. For laser irradiation at 80 mJ/cm2 per pulse, survival rate decreased of three orders of magnitude just after 75 s. The measurement of the absorption cross section for 308 nm photons on Nonomuraea sp. cells was also carried out.
Biodeterioration of Paper: A SEM Study of Fungal Spoilage Reproduced Under Controlled Conditions
Authors: Pinzari Flavia , Pasquariello Giovanna , De Mico Antonella
Published: April 2006

Biodeterioration phenomena represent a complex of physical and chemical alteration processes in various materials, such as those constituting the objects that represent our cultural heritage. The biodegradation of paper is conditioned by several variables such as the materials from which cellulose is obtained, the manufacturing processes employed, the occurrence of other affecting substances such as lignin or metallic compounds, and by the environmental conditions in which papers are conserved. In this study, biodeterioration of paper was artificially induced in order to evaluate the role of a range of chemical and physical variables on damage caused by cellulolytic fungi. A variable pressure SEM instrument was used to characterise paper samples with different fibre origins, and alterations obtained in vitro. Two fungal strains, Aspergillus terreus Thom and Chaetomium globosum Kunze, which are cellulolytic species frequently associated with paper spoilage, were used to produce stains with characteristics close to those observable on art objects made from paper. The stains obtained on the different samples of paper were compared at both low and high magnification, in order to visualize the macro‐ and microscopic characteristics of paper fibres, inorganic constituents, impurities, and the deteriorating agents related to the spoiled areas. During this survey it was observed that single paper characteristics can strongly influence the intensity and the results of the fungal action. For example, the activity of a fungal strain on paper grades containing fibres of the same origin, but with different sizing, led to the formation of profoundly different stains and alterations. Moreover fungal structures, analysed by low vacuum SEM, in areas on paper corresponding to the stains appeared in different physiological states suggesting an important effect of paper constituents on fungal growth and their sporulating ability.
Durability of Protective Polymers: The Effect of UV and Thermal Ageing
Authors: Poli T. , Toniolo L. , Sansonetti A.
Published: April 2006

This paper aimed at studying thermal contribution to the UV ageing process, trying to understand which decisive changes reduce the protective effectiveness of polymer coatings. In this paper the effects on the shielding efficacy of different protective polymers, applied on different low porosity stones have been studied, comparing ageing of a 1000 h simulated solar UV radiation with thermal ageing at about 50 °C, which is the temperature usually reached in UV chambers. The aim of the study has been the evaluation of a possible thermal contribution: the testing methods have been suggested by UNI‐Normal Italian protocol and include capillary water absorption, static contact angles and colour variation measurements. A reduction in protective efficacy has been highlighted, probably due to both oxidation and a surface rearrangement of the polymeric material; in most cases chemical degradation of the macromolecules did not occur.
Efficient DNA Extraction and Amplification of Samples from the Archeological Site of Pompei (Italy)
Authors: Ranalli Giancarlo , Belli Claudia , Lustrato Giuseppe , Meloscia Antonia , Orsini Massimiliano
Published: April 2006

Due to their growth and metabolism, microorganisms can cause severe damage to Cultural Heritage, through mechanical and chemical processes. In this paper we used molecular approaches to study bacterial communities on samples from the archeological site of Pompei (Italy). In particular four DNA extraction methods without prior cultivation of the microflora were compared. In terms of efficiency, the DNA extraction method based on the Tri‐Reagent™ kit gave the best results. All extraction protocols coupled with 16S rDNA fragments PCR amplification were satisfactory; but the best results were obtained by Klentaq DNA LA Polymerase™; this enzyme can be considered an effective tool for amplification of DNA from Cultural Heritage and possibly other environmental samples.
Cover Picture: Macromol. Symp. 238/2006
Authors: Shashoua Yvonne
Published: April 2006

Cover: The 2nd AIV International workshop “Science, Technology and Cultural Heritage” took place in Catania (Italy) between 9th and 11th November 2005. The aims of the workshop were to discuss the state of the art of natural sciences in cultural heritage, to create interdisciplinary collaborations between scientists working in the field of cultural heritage and between scientists and other cultural heritage professionals, such as conservators and curators. One of the main themes of the workshop was the study of macromolecules and their degradation. Macromolecules in cultural heritage occur either as original constituents of works of art or as conservation treatments including consolidants and protective coatings. Both natural and synthetic macromolecules undergo degradation with time and use. As an example, the picture shows a pair of natural rubber shooting gloves from the Danish Defence Museum in Copenhagen. The two gloves are a pair and both date from the 1948, but the right hand glove is highly oxidized due to exposure to ultraviolet light during use, while the left hand glove was rarely used and was not exposed to degradation factors since the soldier was right handed (picture kindly provided by Dr. Yvonne Shashoua).
The 8π‐problem for radially symmetric solutions of a chemotaxis model in the plane
Authors: Biler Piotr , Karch Grzegorz , Laurençot Philippe , Nadzieja Tadeusz
Published: April 2006

The existence, uniqueness and large time behaviour of radially symmetric solutions to a chemotaxis system in the plane ℝ2 are studied either for the critical value of the mass equal to 8π or in the subcritical case. Copyright © 2006 John Wiley & Sons, Ltd.
Regularity in Sobolev spaces of steady flows of fluids with shear‐dependent viscosity
Authors: Ebmeyer Carsten
Published: April 2006

The system

is considered on a bounded three‐dimensional domain under no‐stick boundary value conditions, where S has p‐structure for some p<2 and D(u) is the symmetrized gradient of u. Various regularity results for the velocity u and the pressure π in fractional order Sobolev and Nikolskii spaces are obtained. Copyright © 2006 John Wiley & Sons, Ltd.
Dispersion and attenuation characteristics of asymmetric multiconductor lines in suspended substrate structure using full‐wave modal analysis
Authors: Srivastava Kumar Vaibhav , Awasthi Seema , Biswas Animesh
Published: April 2006

The dispersion characteristics of asymmetric multiconductor lines in shielded suspended substrate (SSS) are evaluated using hybrid‐mode formulation. The numerical procedure, based on full‐wave modal analysis, is formulated to compute all the frequency‐dependent normal‐mode parameters for asymmetric multiconductor lines in a suspended substrate structure. The numerical results include the propagation constants, modal characteristic impedances, and attenuation constant. The perturbation formula has been used for the calculation of conductor and dielectric losses in the suspended substrate structure. Conductor loss is computed for the finite thickness using the perturbation theory and a comparison plot is provided to validate results. Dispersion characteristic of asymmetric three and four coupled microstrip lines in SSS are presented first time in this paper. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 1305–1310, 2006; Published online in Wiley Inter‐Science (www.interscience.wiley.com). DOI 10.1002/mop.21615
Shaped‐reflector antenna designs using particle swarm optimization: An example of a direct‐broadcast satellite antenna
Authors: Xu Shenheng , Rahmat‐Samii Yahya , Gies Dennis
Published: April 2006

A novel shaped‐reflector antenna synthesis technique based on the particle swarm optimization (PSO) algorithm is presented. The reflector surface is expanded using the modified Jacobi polynomials, and the expansion coefficients and other antenna parameters compose a solution space to be explored by PSO in a global stochastic evolutionary manner. The conventional weighted aggregation (CWA) method is utilized when multiple objectives are considered. The validity of this technique is verified by an example application, a shaped‐reflector antenna for simultaneous reception from multiple satellites for direct‐broadcast satellite (DBS) services. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 1341–1347, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21618
Backward‐wave directional coupler with complete coupling and broadband using conventional microstrip and 1D mushroom structure
Authors: Lee Jae‐Gon , Lee Jeong‐Hae
Published: April 2006

A new type of backward‐wave coupled‐line directional coupler with complete coupling and broadband, which is composed of a conventional microstrip and a 1D mushroom structure, is proposed. The 1D mushroom structure is employed for a double negative (DNG) transmission line. The coupler exhibits unusual characteristics such as complex propagation. The complex propagation constant of the coupled mode enables strong coupling due to exponential field decay. The performance of the proposed coupler is verified by c‐ and π‐mode analysis, full‐wave simulation, and measurement. The measured coupling level of −0.5 dB with 3‐dB fractional bandwidth of 35% and high directivity of 30 dB is achieved. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 1293–1296, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21622
Simple models for predicting transmission properties of photonic crystal fibers
Authors: Albandakji Rachad , Safaai‐Jazi Ahmad , Stolen Roger
Published: April 2006

Simple, fast, and efficient 1D models for evaluating the transmission properties of photonic crystal fibers are proposed. Using these models, axial propagation constant, chromatic dispersion, effective area, and leakage loss can be predicted with a reasonable accuracy but much faster than often time‐consuming 2D analytical and numerical techniques and with much less computational resources. It is shown that the results are in good agreement with the published data available in the literature. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 1286–1290, 2006; Published online in Wiley InterScience (www. interscience.wiley.com). DOI 10.1002/mop.21624
Planar compact, broad‐stopband elliptic‐function lowpass filters using high‐permittivity ceramic substrate
Authors: Chen Yuan‐Bin , Huang Cheng‐Liang , Lin Shih‐Hung
Published: April 2006

The miniaturization of hairpin lowpass filters by employing two high‐permittivity ceramic substrates (with respective dielectric constants of 9.7 and 22.6) are investigated. Microwave dielectric ceramics with high permittivity are commonly applied in several microwave communication components. With the advantages of compact size, high‐permittivity ceramics can be used as the substrate for low‐pass filters. Moreover, the fundamental characteristics of newly developed compact stepped‐impedance hairpin resonators with parallel coupled lines have also been described and applied to the design of lowpass filters. In this paper, the designed multiple cascaded stepped‐impedance hairpin resonators structures are simulated using an IE3D simulator. The responses of the fabricated filters using Al2O3 (εr = 9.7, Q × f = 350,000 GHz) and 0.2 Ca0.6La0.26TiO3–0.8Mg0.95Co0.05TiO3 (εr = 22.6, Q × f = 57,000 GHz) ceramic substrates are designed at a cutoff frequency of 1.8 GHz. This compact, low‐loss, sharp cutoff‐frequency response, and broad‐stopband lowpass filter should be useful in many wireless communication systems. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 1432–1436, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21635
A modified dual‐band microstrip monopole antenna
Authors: Lu Lu , Coetzee Jacob Carl
Published: April 2006

A modified microstrip‐fed planar monopole antenna with an open‐circuited coupled line is presented in this paper. The operational bandwidth of the proposed antenna covers the 2.4‐GHz ISM band (2.42–2.48 GHz) and the 5‐GHz WLAN band (5–6 GHz). The radiating elements occupy a small area of 23 × 8 mm2. The finite‐difference time‐domain (FDTD) method is used to predict the input impedance of the antenna. The calculated return loss shows very good agreement with the measured data. Reasonable antenna gain is observed across the operating band. The measured radiation patterns are similar to those of a simple monopole antenna. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 1401–1403, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21636
Tunable fiber laser based fiber Bragg grating strain sensor demodulation system with enhanced resolution by digital signal processing
Authors: Yun Binfeng , Wang Yiping , Li Anmin , Cui Yiping
Published: April 2006

A fiber Bragg grating strain sensor demodulation system based on the wavelength‐tunable fiber‐ring laser (WTFRL) is developed. The finite impulse response (FIR) digital filter and the centriod detection algorithm (CDA) are implemented to reduce the system noises and to improve the resolution of the Bragg wavelength‐shifts detection. The experiments show that with this signal processing technique, the resolution of the fiber Bragg grating (FBG) strain sensor is 1.39 με, which is much better than the resolution (10.1 με) of the direct peak‐detection method. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 1391–1393, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21638
Scalable distributed‐capacitance model for silicon on‐chip spiral inductors
Authors: Huang Fengyi , Lu Jingxue , Jiang Nan
Published: April 2006

We present physics‐based modeling for silicon on‐chip spiral inductors, taking into account the coupling capacitance between metal spirals. The coupling capacitance Cp is calculated using a distributed‐capacitance model based on finite‐element analysis. As demonstrated for a series of inductors with the number of turns ranging from 2.5 to 6.5 fabricated in a 0.18‐μm CMOS technology, the current model provides simulation results for the quality factor Q, the S‐parameter, and the self‐resonance frequency fSR that are in good agreement with the measurements without any fitting parameters. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 1423–1427, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21642
Genetic algorithm demodulation technique for fibre Bragg gratings resonant cavity
Authors: André P. S. , Pellegrino Lara P. , Teixeira A. L. , Nogueira R. N. , Lima M. M. , Monteiro P.
Published: April 2006

We present a demodulation technique to synthesise the physical parameters of an optical fibre Bragg grating (FBG) resonant cavity. The demodulation is achieved through a genetic algorithm (GA). The estimated parameters allow us to simulate the cavity amplitude response, arriving at an accurate response when compared to the experimental results. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 1415–1417, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21644
Novel distortion resilient OSNR monitoring technique based on evaluation of asynchronous histograms
Authors: Luís R. , Teixeira A. , André P. , Monteiro P.
Published: April 2006

This paper presents a novel technique to evaluate OSNR using asynchronous histograms. The technique is based on a comparison between a numerically estimated asynchronous histogram of the signal to be measured and the monitored signal. Experimental validation of proposed technique is presented. Measurement errors below 1 dB are achieved for OSNR values below 32 dB. The proposed technique is also validated for cases where the monitored signal presents significant dispersion‐induced distortion, without presenting significant loss of accuracy. The principal limitations of the proposed technique are also investigated. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 1369–1372, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21648
A subsystem embedded microstrip antenna structure for satellite radio applications
Authors: Chou Hsi‐Tseng , Hsu Chieh‐Sheng
Published: April 2006

A microstrip antenna structure with RF components embedded inside the structure is proposed for satellite radio applications. The space to embed the RF components is created by a metal cavity inside the substrate of the antenna structure. With the increasing use of MMIC techniques, the thickness of the substrate will be sufficient to accommodate the RF components. Hence, the structure has the advantages of a compact subsystem and a small overall system thickness, which may increase a variety of applicable areas. Numerical studies and experimental examinations are performed to validate the performance of the antenna. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 1350–1354, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21650
Compact diplexer and its implementation for wireless communication systems
Authors: Lee Byoung Hwa
Published: April 2006

A new compact and effective lumped‐element diplexer structure targeted for low‐temperature co‐fired ceramic (LTCC) implementation is proposed that can exhibit high levels of isolation between the low‐pass and high‐pass filters. Design equation formulations that take into account the isolation between two filters are presented. As an example, a diplexer for a dual‐mode portable telephone for 900‐MHz digital cellular and 1.9‐GHz personal communication systems is designed and fabricated. According to the measured results, insertion losses within the passbands of low‐pass and high‐pass filters are both less than 0.5 dB. Minimum 20‐dB rejection of low‐pass filter at the passband of high‐pass filter is achieved, and vice versa. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 1413–1415, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21652
Tapered CPW‐fed printed monopole antenna
Authors: Liang Xian‐Ling , Zhong Shun‐Shi , Wang Wei
Published: April 2006

A compact coplanar rectangular monopole antenna fed by a tapered coplanar waveguide (CPW) feeder in the middle of a trapeziform ground plane is introduced. By using the tapered CPW feeder, the impedance bandwidth of the antenna is enhanced by a factor of about 1.7 compared with a 50Ω CPW feeder. The measured ratio impedance bandwidth reaches about 10.7:1, covering frequencies from 0.76 to 8.15 GHz. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 1411–1413, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21653
A design of a microstrip electromagnetic dual‐band bandgap (DB‐EBG) structure
Authors: Çakir Gonca , Sevgi Levent
Published: April 2006

The design, simulation, and experimentation steps of a novel low‐cost, small‐size microstrip electromagnetic dual‐band bandgap (DB‐EBG) structure is presented. The numerical simulations are performed via an in‐house‐prepared 3D finite‐difference time‐domain (FDTD) package and the experiments are carried out using an Agilent‐8714 ES network analyzer. The simulations and measurements confirm that the dual‐stopband characteristics can be controlled via the stub parameters. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 1405–1408, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21655
Wideband EMC chip antenna for WLAN/WiMAX operation in the sliding mobile phone
Authors: Lin Chun‐I , Wong Kin‐Lu , Yeh Shih‐Huang
Published: April 2006

A wideband electromagnetic‐compatible (EMC) chip antenna for application in the sliding mobile phone for WLAN/WiMAX dual‐network operation is presented. The proposed EMC antenna is easily fabricated by mounting a metal pattern onto a foam base of 30 × 6 × 6 mm3. The metal pattern comprises a radiating portion and a vertical ground plane. The radiating portion further consists of a shorted driven strip and a shorted parasitic strip, both of them together generating a wide bandwidth for 2.4‐GHz WLAN operation (2400–2484 MHz) and 2.5‐GHz WiMAX operation (2500–2690 MHz). The vertical ground plane functions as an effective shielding wall and allows the antenna to be in direct contact with nearby electronic components or conducting elements. Small variations on the performances of the proposed antenna for the sliding mobile phone in the slid‐open (talk) and standby conditions are also obtained. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 1362–1366, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21657
A strip loaded dielectric resonator antenna for circular polarisation
Authors: Praveen Kumar A. V. , Hamsakutty V. , Yohannan Jaimon , Mathew K. T.
Published: April 2006

The paper presents an experimental investigation of a cylindrical dielectric resonator antenna (DRA) with a conducting strip loaded on its top surface enabling circular polarisation. A simple 50Ω microstrip transmission line excites the antenna. The reflection, polarisation, and radiation characteristics of the antenna are studied. The antenna exhibits circular polarisation with an axial ratio (AR) < 3 dB over a bandwidth of 3.14% and a beam width of 60°. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 1354–1356, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21660
Tunable side‐polished optical fiber filter using the thermo‐sensitive characteristics of the polymer dispersed liquid crystal
Authors: Lee Cherl‐Hee , Lee Nam‐Kwon , Song Jae‐Won
Published: April 2006

The tunable property of a side‐polished optical fiber filter developed using a polymer dispersed liquid crystal (PDLC) is investigated. The thermo‐sensitive characteristic of the PDLC provides the new type of tunable side‐polished optical fiber filter with a desirable free spectral range (FSR) and eliminates the influence of the high refractive index of indium tin oxide (ITO). As a result, the resonance wavelength of the side‐polished fiber filter is tuned at a rate of −0.015 nm/mW. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 1229–1230, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21662
Three‐antenna MIMO system for WLAN operation in a PDA phone
Authors: Wong Kin‐Lu , Chang Chih‐Hua , Chen Brian , Yang Sam
Published: April 2006

A multiple input multiple output (MIMO) system using three EMC (electromagnetic compatible) chip antennas in a personal digital assistant (PDA) phone is demonstrated. The three EMC chip antennas are mounted at three corners of the system ground plane of the PDA phone and all generate a wide bandwidth covering the wireless local area network (WLAN) operation in the 2.4‐GHz band (2400–2484 MHz). By adding a T‐shaped shorted strip in the proposed MIMO antenna system, large improvements in the isolation (S12, S13, and S23 all less than −20 dB) between any two antennas of the MIMO system are achieved. Detailed effects of the T‐shaped shorted strip on the isolation improvement in the proposed MIMO antenna system are analyzed. Radiation characteristics of the three antennas are also studied. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 1238–1242, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21665
Leaf‐shaped monopole antenna with extremely wide bandwidth
Authors: Bai Xiao‐Feng , Zhong Shun‐Shi , Liang Xian‐Ling
Published: April 2006

A leaf‐shaped monopole antenna with an extremely wide bandwidth is introduced. The antenna is composed of a leaf‐shaped metal sheet with three circular holes vertically mounted on the ground plate covered by a dielectric layer. Its measured −10‐dB return‐loss frequency range is from 1.3 to 29.7 GHz with ratio bandwidth of about 22:1. This antenna provides bandwidth covering the L, C, X, and Ku bands and exhibits a nearly omnidirectional radiation pattern with a simple structure, which is suitable for various military and commercial ultra‐wideband applications. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 1247–1250, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21668
A novel dual‐frequency dual‐polarized stacked patch microstrip array feed for remote sensing reflector antennas
Authors: Kona Keerti S. , Manteghi Majid , Rahmat‐Samii Yahya
Published: April 2006

This paper presents the design and implementation of a dual‐frequency dual‐linear polarized stacked patch array feed with a novel probe‐feeding architecture for future spaceborne synthetic aperture radar (SAR) applications. To facilitate measurements of soil moisture from space, a large aperture antenna of 30 m operating in VHF (137.5 MHz) and UHF (435 MHz) frequencies is desirable. An array feed that synthesizes a rectangular effective aperture on the 30‐m reflector is proposed in order to obtain matched beams at the VHF and UHF frequencies. We focus on the layout, design, and prototype performance of the stacked‐patch microstrip array designed for scaled operating frequencies of 1.13 GHz (lower patch) and 3.57 GHz (upper patch). The study is also aimed at analyzing the performance of the array in combination with a 3.65‐m reflector. Our test results demonstrate a good correlation between the measurements and simulations from finite‐difference time domain (FDTD) and reflector analysis codes, thus validating the design for use in SAR for soil‐moisture applications. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 1250–1258, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21669
Compact broadband gap‐coupled shorted square microstrip antennas
Authors: Deshmukh Amit A. , Kumar Girish
Published: April 2006

Various suspended compact and broadband gap‐coupled variations of edge center‐shorted and corner‐shorted square microstrip antennas, are proposed. These configurations give larger bandwidth with a smaller total patch size as compared to square microstrip antennas. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 1261–1265, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21671
Investigation on spectra of prism‐coupled microdisk resonator
Authors: Yi Fei , Jin Xiaofeng , Zheng Shilie , Zhang Xianmin
Published: April 2006

A prism‐coupled microdisk‐resonator‐based optical filter with the FSR of 15.8 GHz andQvalue of 5.7 × 104is proposed. The theory of the filtering characteristics due to multiloop interference and its dependence on the coupling coefficient is presented. Influence of factors such as the prism‐cavity gap size, the receiving angle, and the receiving position on theQvalue and the resonant frequencies of the spectrum are investigated. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 1265–1269, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21672
Fabrication and measurement of miniaturized Z‐shaped corrugated‐type patch antenna for WLAN
Authors: Lee Won‐Jong , Go Min‐Ho , Kim Yong‐Kyun , Park Hyo‐Dal
Published: April 2006

This paper presents the characteristics of the miniaturized Z‐shaped meander‐type antenna realized for 5.25‐GHz wireless LAN systems. The proposed antenna consists of the modified meander line, corrugated shape, and shorting pin with coaxial feeding on the two‐layered (air and FR4) substrate, which forms the letter “Z.” This proposed antenna has equivalent performance with about 44.87% of size reduction with respect to conventional antennas. Its maximum measured impedance bandwidth (−10‐dB below) is approximately 300 MHz (5.05–5.35 GHz) or 5.76%, which meets to the bandwidth requirement of WLAN (5.15–5.35 GHz) systems. Details of the proposed antenna are described and experimental results of constructed prototypes also are presented. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 1269–1271, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21673
Broadband and high‐gain printed antennas constructed from Fabry–Perot resonator structure using EBG or FSS cover
Authors: Ge Zhi‐Chen , Zhang Wen‐Xun , Liu Zhen‐Guo , Gu Ying‐Ying
Published: April 2006

Fabry–Perot resonators with EBG or FSS cover are introduced to enhance the gain of printed antenna. Based on a systematic comparison study, two kinds of optimization designs are proposed for enhancing the gain and reducing the backward radiation. The validation of the simulated and experimental results confirms that the expected performance is met. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 1272–1274, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21674
Fabrication and measurement of modified spiral‐patch antenna for use as a triple‐band (2.4GHz/5GHz) antenna
Authors: Yoon JoongHan
Published: April 2006

This paper describes the design, fabrication, and measurement of a modified spiral‐patch antenna with a shorting pin. The prototype consists of a modified spiral model and was made using the shorting‐pin method. The prototype of the proposed antenna was designed to achieve triple‐band operation at the 2.4‐ and 5‐GHz bands. To obtain a sufficient bandwidth, a foam layer was inserted between the ground plane and the substrate. This is a microstrip antenna for IEEE 802.11a/b WLAN application. The simulated and measured results for the impedance bandwidth, radiation pattern, and gain are presented and discussed herein. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 1275–1279, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21675
Dual‐linearly‐polarized microstrip array based on composite right/left‐handed transmission line
Authors: Jianfang Zhu Qi Zhu , Wei Lu , Lei Wu , Shanjia Xu
Published: April 2006

A novel dual‐linearly‐polarized microstrip antenna array with series‐feeding configuration is presented. Dual‐linear polarization is excited by upper side‐feeding and lower aperture‐coupled feeding. Meanwhile, the series‐feeding configuration is realized by a composite right/left‐handed transmission line. Compared with the traditional parallel and series‐fed configuration, this array is of simple structure, small area, and high efficiency. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 1366–1369, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21678
Complete assignments of 1H and 13C NMR spectra of leucanthoside A, a new triterpenoid saponin from Cephalaria leucantha L.
Authors: Gođevac D. , Mandić B. , Vajs V. , Menković N. , Macura S. , Milosavljević S.
Published: April 2006

Leucanthoside A, a new allose‐containing triterpenoid saponin (1), was isolated from the aerial parts of Cephalaria leucantha L. Its structure was determined by electrospray ionization mass spectrometry and NMR spectroscopy. Complete assignments of the 1H and 13C NMR chemical shifts were achieved by two‐dimensional NMR experiments: DQF‐COSY, NOESY, TOCSY, HSQC, DINE‐HSQC, HMBC, 13C‐1H 2D‐J‐resolved spectroscopy, and 1,1‐ADEQUATE. Copyright © 2006 John Wiley & Sons, Ltd.
Explicit and semi‐implicit CBS procedures for incompressible viscous flows
Authors: Massarotti N. , Arpino F. , Lewis R. W. , Nithiarasu P.
Published: April 2006

This paper presents a numerical comparison of two different numerical procedures based on the characteristic‐based split (CBS) algorithm for the solution of incompressible flows. The first procedure is based on the original semi‐implicit version of the CBS, introduced in the early days of the scheme development. The second was proposed more recently in order to have a fully explicit version of the scheme, and is based on the introduction of an artificial compressibility type of formulation. The interest in fully explicit schemes has increased because of the easy and efficient parallelization. The main differences between the two versions of the schemes are highlighted in this work, and a numerical comparison is presented on the basis of several benchmark solutions. Both steady and unsteady flows are considered. With the explicit version of the scheme a dual time stepping procedure is needed to recover unsteady solutions. Copyright © 2006 John Wiley & Sons, Ltd.
Efficient explicit time stepping for the eXtended Finite Element Method (X‐FEM)
Authors: Menouillard T. , Réthoré J. , Combescure A. , Bung H.
Published: April 2006

This paper focuses on the introduction of a lumped mass matrix for enriched elements, which enables one to use a pure explicit formulation in X‐FEM applications. A proof of stability for the 1D and 2D cases is given. We show that if one uses this technique, the critical time step does not tend to zero as the support of the discontinuity reaches the boundaries of the elements. We also show that the X‐FEM element's critical time step is of the same order as that of the corresponding element without extended degrees of freedom. Copyright © 2006 John Wiley & Sons, Ltd.
Suppression of human selenium‐binding protein 1 is a late event in colorectal carcinogenesis and is associated with poor survival
Authors: Kim Hyunki , Kang Hyun Ju , You Kwon Tae , Kim Se Hoon , Lee Kang Young , Kim Tae Il , Kim Chul , Song Si Young , Kim Hye‐Jung , Lee Cheolju , Kim Hoguen
Published: April 2006

The purpose of this study was to analyze altered protein expression in cancer tissues and determine its relationship to prognosis in colorectal carcinomas. We performed proteomic expression analysis on 14 colorectal carcinomas and matched nontumorous colonic mucosa by 2‐DE and MALDI‐TOF‐MS. Comparative analysis of the respective spot patterns on 2‐DE showed 14 spots that were markedly changed in the colorectal carcinomas. Among them, selenium‐binding protein 1 (SELENBP1) was markedly decreased in 12 (85%) carcinomas. The reduced expression of SELENBP1 was further supported by Western blot analysis and immunohistochemistry. Suppression of SELENBP1 was further analyzed in another eight‐paired adenomas and carcinomas from the same patients using Western blot analysis and immunohistochemistry, and revealed that one adenoma and seven carcinomas exhibited markedly reduced SELENBP1 expression. Patients with low levels of SELENBP1 expression had significantly lower overall survival rates (72 vs. 85%, p = 0.021) among the 240 stages II and III colorectal carcinomas by using tissue microarray analysis. Our findings indicate that suppression of SELENBP1 is a frequent and late event in colorectal carcinogenesis, and may contribute to the rapid progression of colorectal carcinoma.
Poly(dimethylsiloxane)‐based polymer organogelators with L‐lysine derivatives as a organogelation‐causing segment
Authors: Suzuki Masahiro , Owa Sanae , Shirai Hirofusa , Hanabusa Kenji
Published: April 2006

New poly(dimethylsiloxane)‐based polymer organogelators with L‐lysine derivatives were synthesized on the basis of synthetically simple procedure, and their organogelation abilities were investigated. These polymer organogelators have a good organogelation ability and form organogels in many organic solvents. In the organogels, polymer gelators constructed a mesoporous structure with a pore size of about 1 μm formed by entanglement of the self‐assembled nanofibers. The L‐lysine derivatives in the polymer gelators functioned as a gelation‐causing segment and the organogelation was induced by self‐assembly of the L‐lysine segments through a hydrogen bonding interaction. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 3817–3824, 2006
Eu2+, Eu3+ and Sm3+ emission in SrAl12O19 phosphors prepared via combustion synthesis
Authors: Singh Vijay , Zhu Jun‐Jie , Natarajan V.
Published: April 2006

Strontium hexa‐aluminate phosphors activated with Eu3+ and Sm3+ ions were produced at low temperatures (500 °C) by the combustion of corresponding metal nitrate–urea mixtures over a period of 5 min. Powder X‐ray diffraction characterization and photoluminescence studies of these samples were carried out. It was found that co‐doping of Sm3+ ions helps in the partial reduction of Eu3+ ions to Eu2+ ions in SrAl12O19. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Fluorescence spectroscopic study of the phase transformation of γ‐Al2O3 at high temperatures
Authors: Luo Meng‐Fei , Fang Ping , He Mai , Xie Yun‐Long
Published: April 2006

The phase transformation of γ‐Al2O3 at high temperatures was characterized using X‐ray diffraction (XRD) and fluorescence techniques. The results of a comparative fluorescence spectroscopic study of commercial and pure Al2O3 show that with laser excitation at 632.8 and 514.5 nm the absorption bands at 683.8 and 686.7 nm (R‐line luminescence) are attributed to the presence of Cr3+ ions in octahedral coordination in a θ‐Al2O3 environment. The other two bands at 692.8 and 694.4 nm (R2 and R1 lines) are attributed to Cr3+ fluorescence in an α‐Al2O3 environment. Compared with XRD measurements, fluorescence spectroscopy has a higher sensitivity for identification of phase transformations in θ‐Al2O3 and α‐Al2O3. According to the different absorptions of Al2O3 with two laser excitations, the laser excitation at 514.5 nm is found to be more sensitive at the surface region while the laser excitation at 632.8 nm supplies information about the bulk. The fluorescence spectra together with UV–visible diffuse reflectance spectra and XRD patterns indicate that the γ‐Al2O3 starts transforming to θ‐Al2O3 and α‐Al2O3 simultaneously at 800 °C. However, the θ‐Al2O3 and α‐Al2O3 compositions of the surface region and the bulk are different. The α‐Al2O3 content at the surface region is higher than that in the bulk. The γ‐Al2O3 sample transforms to α‐Al2O3 completely at 1250 °C. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)