bluuebunny/crossref_metadata_2025 huggingface dataset:
Assessment of the Neotropical dry forest refugia hypothesis in the light of palaeoecological data and vegetation model simulations
Authors: Mayle Francis E.
Published: September 2004

Seasonally dry tropical forests exhibit a markedly discontinuous, disjunct distribution pattern across South America. Previous botanical inventories have revealed that these dry forest areas exhibit close floristic links with one another, which has led to the hypothesis that they constitute modern‐day refugia, resulting from vicariance (i.e. fragmentation) of a formerly more widespread, continuous distribution during more arid climatic conditions associated with the Last Glacial Maximum (LGM). This paper examines the validity of this ‘dry forest refugia’ hypothesis in the light of previously published fossil pollen data and vegetation model simulations. The model simulations suggest that major dry forest areas, such as the Bolivian Chiquitano Dry Forest, are not Pleistocene refugia, but instead developed during the Holocene by population expansions from parts of southern Amazonia presently covered by evergreen rainforest. The limited pollen data available indicate that glacial‐age seasonally dry tropical forests, irrespective of their distribution, were floristically quite different from those of today, with key dry forest species, such as Anadenanthera, only appearing in the Holocene. I suggest that a more parsimonious explanation for the current biogeographic pattern of these South American dry forests is population migration (perhaps by long‐distance dispersal) since the LGM, rather than vicariance. Copyright © 2004 John Wiley & Sons, Ltd.
Vibrational spectral studies of (β‐alanine) β‐alaninium nitrate
Authors: Jinnah M. Mohamed Ali , Umadevi M. , Ramakrishnan V.
Published: September 2004

Laser Raman and infrared spectra of (β‐alanine) β‐alaninium nitrate were recorded and analyzed at room temperature. The proposed assignment of normal modes is based on group theoretical analysis. The hydrogen atom is shared by two amino acids, leading to switching of roles of the cation and zwitterion. The two alanine groups share one proton and become monoprotonated. The presence of an ionized carboxylic group and carbonyl was identified. The extensive hydrogen bonding in the crystal is responsible for the changes in the position and intensity of several bands. The nitrate anion fundamentals, however, continue to be degenerate. Copyright © 2004 John Wiley & Sons, Ltd.
Thermochemical properties from G3MP2B3 calculations, Set‐2: Free radicals with special consideration of CH2CHC•CH2, cyclo−•C5H5, •CH2OOH, HO•CO, and HC(O)O•
Authors: Janoschek R. , Rossi M. J.
Published: September 2004

After a set of 32 free radicals was presented (Int J Chem Kin 34, 550–560, 2002), an additional 60 free radicals (Set‐2) were studied and characterized by energy minimum structures, harmonic vibrational wave numbers ωe, moments of inertia IA, IB, and IC, heat capacities Cop(T), standard entropies So(T), thermal energy contents Ho(T) − Ho(0), and standard enthalpies of formation ΔfHo(T) at the G3MP2B3 level of theory. Thermodynamic functions at T = 298.15 K are presented and compared with recent experimental values where these are available. The mean absolute deviation between calculated and experimental ΔfHo(298.15) values by the previous set of 32 radicals is 3.91 kJ mol−1. For the sake of comparison, only 49 species out of the 60 radicals of Set‐2 are characterized by experimental enthalpies of formation, and the corresponding mean absolute deviation between calculated and experimental ΔfHo(298.15) values is 8.96 kJ mol−1. This situation is cause for demand of more and also more accurate experimental values. In addition to the above properties, parent molecules of a large set of the respective radicals are calculated to obtain bond dissociation energies Do(298.15). Radical stabilization owing to resonance is discussed using the complete sets of total atomic spin densities ρ as a support. In particular, a short review about recent developments of the first‐order Jahn–Teller radical c‐C5H5• is presented. In addition, radicals with negative bond energies are described, such as •CH2OOH where the reaction path to CH2O + HO• has been calculated, as well as radicals which have two different parent molecules, for example CNO•. For the reaction HO• + CO → H• + CO2, two reaction paths are characterized by a total of 14 stationary points where the intermediate radicals HO•CO and HC(O)O• are involved. © 2004 Wiley Periodicals, Inc. Int J Chem Kinet 36: 661–686, 2004
UV‐Curable Organic‐Inorganic Hybrid Film Coatings Based on Epoxidized Cyclohexene Derivatized Linseed Oil
Authors: Zou Kunrong , Soucek Mark D.
Published: September 2004

Summary: Organic‐inorganic hybrid films based on epoxidized cyclohexene derivatized linseed oil (ECLO) and tetraethylorthosilicate (TEOS) oligomers were prepared via a UV‐curing process. The kinetics of the hybrid materials were studied by photo‐differential scanning calorimetry (DSC). In addition to the kinetics, the tensile properties, pencil hardness, pull‐off adhesion, reverse impact resistance, solvent resistance and abrasion resistance of the hybrid coatings were evaluated. Both dynamic mechanical thermal analysis (DMTA) and thermogravimetric analysis (TGA) were used to investigate the viscoelastic and thermal properties of the hybrid films. The morphology of the hybrid film was characterized by atomic force microscopy (AFM). Based on the results from the aforementioned evaluation of the coatings, the hybrid films exhibited higher pencil hardness, tensile strength, tensile modulus, fracture toughness, abrasion resistance, cross‐link density and thermal stability compared to the ECLO organic film. The Photo‐DSC data showed that the photo‐curing speed of the hybrid materials increased with TEOS oligomers content. It was postulated that the TEOS oligomers were reactive diluents.

Structure of ECLO.

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Structure of ECLO.
Studies on Molecular Composites of Polyamide 6/Polyamide 66
Authors: Li Yulin , Yang Guisheng
Published: September 2004

Summary: A series of molecular composites of PA 6/PA 66 was synthesized via in situ polymerization. The impact resistance of PA 6 was improved dramatically by incorporating a minor amount of PA 66 (2–10 wt.‐%), without decreasing the tensile strength. Inserting PA 66 macromolecules at a molecular level into a PA 6 matrix may interfere with the arrangement of the hydrogen bonds of PA 6, in turn changing the crystalline structure and impeding the crystallization of PA 6.

SEM micrograph of the fractured surface of a PA 6/PA 66 composite containing 10 wt.‐% PA 66.

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SEM micrograph of the fractured surface of a PA 6/PA 66 composite containing 10 wt.‐% PA 66.
Simple Preparation of Sulfate Anion‐Doped Polyaniline‐Clay Nanocomposites by an Environmentally Friendly Mechanochemical Synthesis Route
Authors: Yoshimoto Shoji , Ohashi Fumihiko , Kameyama Tetsuya
Published: September 2004

Summary: Conducting polyaniline (PANI) and montmorillonite (MMT) nanocomposites were prepared from aniline sulfate and MMT by a mechanochemical synthesis route. X‐Ray diffraction analysis confirmed that, by controlling the aniline sulfate content, mechanochemical synthesis led to two types of different formations. After polymerization, the mechanochemical route synthesized much more PANI between the clay layers compared to a solution method. The electrical conductivities of the synthesized PANI‐MMT nanocomposites in pressed pellets ranged in the order of between 10−4 and 10−3 S · cm−1.

X‐ray powder diffraction patterns of the intercalation products prepared by grinding montmorillonite with various amounts of Ani‐SO4 in a mortar.

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X‐ray powder diffraction patterns of the intercalation products prepared by grinding montmorillonite with various amounts of Ani‐SO4 in a mortar.
Electron Transfer Reactions of Radical Anions with TEMPO: A Versatile Route for Transformation of Living Anionic Polymerization into Stable Radical‐Mediated Polymerization
Authors: Cianga Ioan , Senyo Takamichi , Ito Koichi , Yagci Yusuf
Published: September 2004

Summary: The possibility of transforming a living anionic polymerization into a stable radical‐mediated radical polymerization (SFRP) was demonstrated. For this purpose, 2,2,6,6‐tetramethylpiperidine‐N‐oxyl (TEMPO) alcoholate, formed by a one‐electron redox reaction between potassium naphthalene and TEMPO, was used to initiate the living anionic polymerization of ethylene oxide (EO). Poly(ethylene oxide) obtained in this way possessed TEMPO terminal units and was subsequently used as an initiator for the SFRP of styrene to give block copolymers.

A one‐electron redox reaction gives rise to TEMPO alcoholate, which is able to initiate the living anionic polymerization of ethylene oxide (EO).

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A one‐electron redox reaction gives rise to TEMPO alcoholate, which is able to initiate the living anionic polymerization of ethylene oxide (EO).
(Star PS)‐block‐(Linear PI)‐block‐(Star PS) Triblock Copolymers – Thermoplastic Elastomers with Complex Branched Architectures
Authors: Huang Tianzi , Knauss Daniel M.
Published: September 2004

Polystyrene‐block‐polyisoprene‐block‐polystyrene triblock copolymers were synthesized with star‐shaped branching in the polystyrene phase. The block copolymers were formed through sequential anionic polymerization by first synthesizing linear polystyrene, followed by star coupling using 4‐(chlorodimethylsilyl)styrene, then the polymerization of isoprene, followed by difunctional coupling with dichlorodimethylsilane. The polymerization was followed by gel permeation chromatography and the resulting copolymers were characterized by 1H NMR spectroscopy to examine the polyisoprene microstructure.
Synthesis of Poly(1,3‐cyclohexadiene) Containing Star‐Shaped Elastomers
Authors: Williamson D.T. , Long T.E.
Published: September 2004

The synthesis of high molecular weight star‐shaped polymers comprising poly(1,3‐cyclohexadiene‐block‐isoprene) diblock arms coupled to a divinyl benzene (DVB) core is reported. The number average molecular weights of the diblock arms were varied from 30000 to 50000 and the ratio of DVB to n‐butyllithium (nBuLi) was systematically varied from 3:1 to 12:1. Size exclusion chromatography coupled with light scattering detection was utilized to detect the formation of star‐shaped polymers and the presence of star‐star coupling. The molecular weight distribution (/) of the star polymers ranged from 1.25 to 1.50. The effect of poly(1,3‐cyclohexadiene) content on the mechanical properties of these novel elastomers is reported. The elastic modulus, elongation at break, and tensile strength of these elastomers were all found to be a function of the percentage of poly(1,3‐cyclohexadiene). The glass transition temperatures were determined using both differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA). Atomic force microscopy was performed in the tapping mode (TMAFM) to verify the presence of microphase separation.
Triblock and Radial Star‐Block Copolymers Comprised of Poly(ethoxyethyl glycidyl ether), Polyglycidol, Poly(propylene oxide) and Polystyrene Obtained by Anionic Polymerization Initiated by Cs Initiators
Authors: Dimitrov Ph. , Rangelov St. , Dworak A. , Haraguchi N. , Hirao A. , Tsvetanov Ch.B.
Published: September 2004

The anionic polymerization of ethoxyethyl glycidyl ether (EEGE) initiated by cesium alkoxide was studied. The ring‐opening polymerization of EEGE in the presence of cesium alkoxide of 1‐methoxy‐2‐ethanol does not involve any side reactions. The presence of an additional alcohol leads to a significant increase of the initiator efficiency.

Aqueous solutions of poly (ethoxyethyl glycidyl ether) (PEEGE) exhibit lower critical solution temperature (LCST), and the polymer solubility in water is extremely sensitive to its MW. Two novel types of block copolymers based on PEEGE were synthesized: triblock‐copolymers of ABA (A′:BA′) structure, where A is the PEEGE block, A′ polyglycidol (PG) and B the polypropylene oxide (PPO) block, and A2S (A′2S) and A4S (A′4S) heteroarm stars, where S is the polystyrene block.

The synthesis of the ABA block was performed by polymerization of EEGE initiated by bi‐functional PPO/Cesium alkoxide macroinitiator. The PEEGE blocks were converted into PG blocks by successful cleavage of the ethoxyethyl group.

Polystyrene/PEEGE and polystyrene/PG three‐ and five‐ heteroarm star copolymers were synthesized by a coupling reaction between well‐defined chain‐end‐functionalized polystyrenes carying dendritic benzyl bromide moieties with living anionic polymers of PEEGE with one cesium alkoxide terminal group. The coupling reaction proceeds quantitatively without any side reactions, and thus series of star‐branched polymers can be systematically synthesized. Polystyrenes with two or four PG arms have been obtained after the cleavage of the protecting group. The compact structure of these multi‐arm star polymers and their amphiphilic character leads to the formation of nanoparticles in aqueous solution with rather uniform size distribution and a mean diameter of 15 nm.
Telechelic Polyisobutenes with Asymmetrical Reactivity
Authors: Lange Arno , Rath Hans‐Peter , Lang Gabriele
Published: September 2004

3‐Chlorocyclopentene‐(1) has been used as initiator in the quasiliving cationic polymerization of isobutene. Polyisobutenes in the molecular weight range Mw = 300 ‐ 60000 Dalton with a molecular weight distribution MWD between 1.17 and 1.34 have been synthesized. The linear polymer was selectively hydrosilated on one or both ends. With a furan coupling agent, the PIB (polyisobutene) was dimerized, yielding polymers with a cyclopentene head‐ and tail group.
Amphiphilic Polymers Based on Poly(2‐oxazoline)s – From ABC‐Triblock Copolymers to Micellar Catalysis
Authors: Nuyken Oskar , Weberskirch Ralf , Bortenschlager Martin , Schönfelder Daniel
Published: September 2004

In this presentation we give an overview on our results in the field of poly(2‐oxazolines). By means of living cationic polymerization in combination with the initiation and termination method, functionalized poly(2‐oxazoline)s have been prepared, that were used as (i) macromonomers to form graft copolymers, (ii) lipopolymers to prepare stealth liposomes, (iii) ABC like polymers to form two compartment micellar networks and (iv) macroligand for micellar catalysis application. Within this report, we will discuss in detail the synthesis and characterization of various poly(2‐oxazoline)s for the above mentioned research areas.
Dual Reactivity of Magnesium Compounds as Initiators for Anionic and Cationic Polymerization
Authors: Arest‐Yakubovich Alexander , Nakhmanovich Boris , Zolotareva Irina , Yakimansky Alexander , Pakuro Natalia
Published: September 2004

Organomagnesium compounds are well known initiators of anionic polymerization of polar monomers. However, we have found recently that in the presence of compounds with labile halogen atoms, e.g., benzyl chloride, they are also active initiators of cationic polymerization of isobutylene and styrene in hydrocarbon media. The tentative scheme of cationic initiation is suggested assuming the formation of benzyl cation connected with Mg2Cl5− counter‐ion. The scheme is confirmed by quantum‐chemical calculations and 1H NMR analysis of polyisobutylene. On addition of a polar monomer, N,N‐dimethylacrylamide or 2‐vinylpyridine, to Bu2Mg‐BzCl‐isobutylene polymerizing mixture, the former readily polymerizes. The mixture of homopolymers rather than block copolymers is formed in this case, however, this fact proves the co‐existence of anionic and cationic centers in the system.
Templating Organosilicate Vitrification Using Unimolecular Self‐Organizing Polymers Prepared from Tandem Ring Opening and Atom Transfer Radical Polymerizations
Authors: Magbitang T. , Lee V.Y. , Connor E.F. , Sundberg L.K. , Kim H.‐C. , Volksen W. , Hawker C.J. , Miller R.D. , Hedrick J.L.
Published: September 2004

A unimolecular templating star‐shaped polymer with a compatibilizing outer corona, prepared by tandem ROP/ATRP procedures, was dispersed into a thermosetting organosilicate. The organic polymer was thermalized to leave behind its latent image in the matrix with a pore size that reflected the size of the polymer molecule, and provided the expected reduction in dielectric constant.
Detection of PEC elliptic cylinders by a memetic algorithm using real data
Authors: Caorsi S. , Massa A. , Pastorino M. , Randazzo A.
Published: September 2004

A global optimization procedure for the electromagnetic detection of perfectly conducting elliptic cylinders is proposed. The method is based on an analytical solution for the forward‐scattering computation. The problem is recast as an optimization problem by constructing a suitable functional, which is minimized by using an efficient memetic algorithm. The solution is validated by using real data obtained from a prototype of an imaging system based on the modulated scattering technique. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 43: 271–273, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20442
Time‐domain 3D electromagnetic model for hybrid and monolithic microwave and optoelectronic integrated circuits
Authors: Mohammadi F. A. , Yagoub M. C. E. , Raahemifar K.
Published: September 2004

This paper presents an accurate and robust 3D time‐domain electromagnetic model for hybrid and monolithic microwave and optoelectronic integrated circuits. The time‐domain model has been validated for different structures, such as metallic waveguides and planner lines under harmonic‐oscillation excitation. The simulation results demonstrate that this approach is suitable for modeling microwave components of integrated circuits. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 43: 276–280, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20444
Demonstration of reflection‐error reduction in antenna radiation patterns using spherical wave expansion
Authors: Koivisto Päivi
Published: September 2004

This paper demonstrates how the reflection error of a radiation pattern can be reduced by means of an optimised spherical wave expansion (SWE). Disturbed and undisturbed radiation patterns are measured with and without an aluminum mast near the measured antenna. The SWEs are calculated from each measurement with the optimal truncation indices determined by a method previously introduced by this author. The differences between the disturbed and undisturbed radiation patterns are calculated for measured and corresponding SWE values. The agreement of the SWE fields is better than that of the measured ones. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 43: 280–284, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20445
Design and implementation of a multiband planar antenna for cellular/PCS/IMT‐2000 base stations
Authors: Oh Kyungjin , Kim Bonjun , Choi Jaehoon
Published: September 2004

In this paper, a novel dual‐frequency wideband aperture‐stacked patch antenna for cellular/PCS/IMT‐2000 base stations is presented. It consists of single microstrip patch with notches along the radiating patch, two dielectric substrates, and foam material. By the proper choice of the resonant aperture size and height of the foam material, dual and wideband characteristics can be realized. The measured impedance bandwidth (1:1.5 VSWR) of the designed antenna at the lower band (860 MHz) reaches 77 MHz and covers the cellular CDMA band (824–894 MHz). The measured impedance bandwidth (1:1.5 VSWR) of the designed antenna at the upper band (1960 MHz) is about 550 MHz and covers both the PCS (1750–1870 MHz) and IMT‐2000 (1920–2170 MHz) bands. Good broadside radiation with high gain (6.92–7.92 dBi) characteristics are also observed. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 43: 284–286, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20446
On the multiplaten Z‐buffer algorithm for ray tracing in high‐frequency electromagnetic scattering computations
Authors: Zhou Yong , Ling Hao
Published: September 2004

A ray tracer based on the multiplaten Z‐buffer (MPZ) algorithm is implemented and its performance is evaluated against the binary space‐partition tree algorithm. Our results indicate that the computational complexity of the MPZ is independent of the number of facets, thus making it potentially attractive for targets described by a large number of facets. A multi‐aspect MPZ (MAMPZ) is also proposed to further enhance the speed performance of the MPZ algorithm. It is shown that by storing multi‐aspect Z‐buffers, it is possible to significantly accelerate the ray‐tracing time of the MPZ. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 43: 298–301, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20450
A compact low‐pass filter with ultra‐wide stopband
Authors: Kim Kyunghoon , Jung Jong‐Ho , Kee Chul‐Sik , Park Ikmo , Lim H.
Published: September 2004

This paper presents a compact microstrip low‐pass filter with ultra‐wide stopband and sharp cutoff frequency response. The conventional shunt open‐stub filter with a slot on the ground plane has a wide stopband at high frequency, and the coupled open‐stub microstrip filter has a sharp cutoff response at low frequency. The combination of these structures gives the filter the characteristics of an ultra‐wide stopband and a prominent cutoff sharpness. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 43: 303–306, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20452
Novel geometrical database model for line‐based GIS urban maps in 2D/2.5D ray‐tracing algorithms
Authors: Liu Haitao , Li Binhong , Qi Dongsheng
Published: September 2004

Conventional geometrical database models (GDMs) in ray tracing require vectorization of building information, thus cannot achieve datum‐extraction from line‐based GIS maps efficiently, in which the building layouts are mainly stored in scalar lines. A novel GDM with an improved algorithm in 2D/2.5D cases is proposed according to this kind of map. A comparison between the simulation and measurement results verifies the validity of the new model and method. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 43: 307–310, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20453
Circuit‐level simulation of W‐CDMA communication systems applied to the analysis of nonlinear distortion
Authors: Madero‐Ayora María J. , Reina‐Tosina Javier , Freire‐Pérez Ramón , Crespo‐Cadenas Carlos
Published: September 2004

Different circuit‐level approaches to analyze the effects of nonlinear distortion on coded division multiple access (CDMA) wireless communication systems are studied in order to predict spectral regrowth at the output of a nonlinear device. Measurements of a simple MESFET amplifier tested with a W‐CDMA waveform are satisfactorily compared with the simulated results. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 43: 310–314, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20454
A broadband high‐efficiency bow‐tie slot antenna for WLAN applications
Authors: Denidni Tayeb A. , Rao Qinjiang , Sebak Abdel R. , Talbi Larbi
Published: September 2004

A new broadband high‐efficiency bow‐tie slot antenna is proposed for wireless local area network (WLAN) applications in dual‐frequency bands (5.15–5.35 GHz and 5.728–5.825 GHz). To achieve this objective, the radiating slot is fed by a new feeding circuit by using a microstrip line with a strip fork tuning stub. By optimizing the parameters of the antenna structure, one can let the frequency band of the antenna meet and exceed the band requirements of WLAN applications, and the radiation efficiency can be up to more than 90% in the interested bands. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 43: 317–320, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20456
Gain enhancement by optimizing the interelement spacing in linear array antennas
Authors: Aerts W. , Vandenbosch G. A. E.
Published: September 2004

In this paper, an easy design method is introduced for the optimal linear array, that is, the array with the highest possible gain. This technique is only exact for isotropically radiating elements, but can easily be used for an array of any element type with a rotation‐symmetric radiation pattern. The quality of this approximation is discussed for an array of dipoles. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 43: 320–324, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20457
A simple temperature‐independent strain sensor using a fiber BRAGG grating
Authors: Zhao Zhiyong , Zhang Shuang , Yu Yongsen , Zhuo Zhongchang , Qian Ying , Cao Yinghui , Zhang Jian , Zheng Wei , Zhang Yushu
Published: September 2004

A novel temperature‐independent strain sensor based on a fiber Bragg grating is demonstrated. The front section of the fiber Bragg grating is fixed to a crystal plate, and the other section is linearly etched in HF acid. The reflected power of the grating varies linearly with strain and is insensitive to temperature variation. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 43: 324–326, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20458
A quadratic‐programming approach to the synthesis of multifrequency broadside antenna arrays
Authors: McNamara Derek A.
Published: September 2004

An array synthesis technique that straightforwardly extends an earlier quadratic‐programming based method to the case of multifrequency arrays is described. The method is applied to a specific multifrequency array example. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 43: 326–330, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20459
Low pass filter implementation with loaded coplanar strip‐lines over GaAs semi‐insulating substrates
Authors: Cantú H. I.
Published: September 2004

This paper reports the design, fabrication, and testing of novel low‐pass filters based on periodic capacitively loaded coplanar strip‐lines on GaAs substrates. The main feature of these filters is the simplicity of the fabrication process and the reduction of radiation losses and layout dimensions. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 43: 330–332, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20460
A novel method for switching and tuning of PBG structures
Authors: Wu Jack , Qiu S. N. , Qiu C. X. , Shih I.
Published: September 2004

Photonic band‐gap (PBG) structures are utilized in microwave components as filters to suppress unwanted signals. In this work, rectangular perforations were created in the ground plane of a microstrip line to construct a PBG structure. A gold‐coated alumina substrate was utilized to switch or tune the bandstop characteristics of this structure. It was demonstrated that the bandstop characteristics were switched off from −35 to −1 dB at 16 GHz. Tuning of the bandstop edge with a shift of 1.5 GHz was also shown. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 43: 334–337, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20462
On single‐mode transmission of variable ferrite polarizers in circular waveguide
Authors: Che Wenquan , Yung Edward K. N.
Published: September 2004

High‐order modes are a problem in the design of many ferrite devices. The characteristic equation for the modes in a ferrite variable polarizer, implemented in a dielectric‐filled circular waveguide, is obtained using the mode‐matching method. The conditions to guarantee single‐mode (TE11) operation are also determined. It is shown that when the ferrite thickness has been chosen as t = 0.0377λ0, the valid range of the dielectric thickness should be 0.01λ0 < d < 0.0146λ0 for single‐mode operation. It is shown that the dielectric ring filling can improve the figure of the merit and help to realize the single‐mode transmission in the device. Experimental results from a prototype polarizer are provided as verification of the analysis presented here. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 43: 348–353, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20466
Microwave imaging of two‐dimensional dielectric cylinders with a multiscaled frequency hopping approach
Authors: Thomas Vinu , Gopakumar C. , Lonappan Anil , Bindu G. , Hamsakutty V. , Mathew K.T.
Published: September 2004

A multiscaled multifrequency method for inverse profiling of 2D dielectric cylinders is presented. The inverse problem is solved at all frequency hops using a multiscale scheme: the problem is solved at a coarse resolution where it is more stable, and this solution is used as a starting estimate for solving the problem at progressively increasing scales. Multiscaling reduces the risk of the solution getting trapped in a local minimum with respect to the deterministic optimization method employed for the inverse‐scattering problem. Thus, better initial estimates are provided for the iterations at higher frequencies. Testing the strategy on synthetic multifrequency data provides promising results. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 43: 353–355, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20467
Translational Doppler detection using direct‐detect chirped amplitude‐modulated laser radar
Authors: Ruff W. , Aliberti K. , Giza M. , Potter W. , Redman B. , Stann B.
Published: September 2004

Translational Doppler detection using a direct‐detect, chirped, amplitude‐modulated LADAR is demonstrated. A nonoptically coherent system is utilized to lower the target‐induced Doppler shift to tens of Hz, as opposed to several hundreds of megahertz for a coherent LADAR design. The Doppler shift is imposed on both the laser carrier and the intensity modulation impressed on the laser carrier. The data indicate that the LADAR is able to measure the Doppler shift due to the translational motion of a moving target. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 43: 358–363, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20469
Cardiac and skeletal muscle involvement in myotonic dystrophy type 2 (DM2): A quantitative 31P‐MRS and MRI study
Authors: Schneider‐Gold Christiane , Beer Meinrad , Köstler Herbert , Buchner Stefan , Sandstede Jörn , Hahn Dietbert , Toyka Klaus V.
Published: September 2004

In myotonic dystrophy type 2 (DM2/PROMM), cardiac muscle involvement is usually more benign than in DM1, but clinically severe cardiomyopathy has been reported in some patients. Using a novel method of magnetic resonance spectroscopy (MRS), we examined the left ventricular myocardium and the left gastrocnemius muscle in 11 unselected DM2/PROMM patients without overt cardiac disease. Data on cardiac morphology and function were obtained by gradient echo two‐dimensional cine magnetic resonance imaging (MRI); no significant differences were found between DM2 patients and healthy controls, but using a median split approach older patients showed mildly increased left ventricular (LV) volumes, i.e., 59% increase of end‐systolic volume index (ESVI) and 35% increase of end‐diastolic volume index (EDVI), and an increase of LV mass (26%). On cardiac MRS, DM2/PROMM patients showed a reduction of phosphocreatine (PCr) and adenosine triphosphate (ATP) by 25 and 20% compared to matched healthy controls. No significant differences were found between younger and older patients. In skeletal muscle of the DM2 patients, no significant decrease of PCr and ATP concentrations was found. However, in older patients, who commonly show overt hip flexor muscle weakness, we observed reduced values for PCr and ATP. Our MRS and MRI findings reveal evidence for subclinical cardiomyopathy in DM2/PROMM patients without overt heart disease. Future prospective studies are needed to clarify the risk of developing overt cardiac disease in DM2 and to define prognostic factors. Muscle Nerve, 2004
Graph distance‐dependent labeling related to code assignment in computer networks
Authors: Jin Xiaohua Teresa , Yeh Roger K.
Published: September 2004

For nonnegative integers d1, d2, and L(d1, d2)‐labeling of a graph G, is a function f : V(G) → {0, 1, 2, …} such that |f(u) − f(v)| ≥ di whenever the distance between u and v is i in G, for i = 1, 2. The L(d1, d2)‐number of G, λ(G) is the smallest k such that there exists an L(d1, d2)‐labeling with the largest label k. These labelings have an application to a computer code assignment problem. The task is to assign integer “control codes” to a network of computer stations with distance restrictions, which allow d1 ≤ d2. In this article, we will study the labelings with (d1, d2) ∈ {(0, 1), (1, 1), (1, 2)}. © 2004 Wiley Periodicals, Inc. Naval Research Logistics, 2005
Augen auf beim Hürdenlauf — Projekt‐Risikomanagement im Rahmen der Einführung eines Gesamtbankeninformatiksystems am Beispiel der Bank Linth
Authors: Kessler Bernhard , Küttel Paolo
Published: September 2004

Mit der Informatik verbundene Risiken stellen einen bedeutenden Anteil des operativen Risikos einer Bank dar. Der technologische Forschritt, die wachsende IT‐Abhängigkeit des Bankgeschäfts sowie der zunehmende Trend zum Sourcing bedingen in der heutigen Zeit eine kontinuierliche Anpassung der bestehenden IT‐ und Kommunikationssysteme. Diesem Trend entsprechend wurden in der Schweiz, trotz der angespannten Situation in der Bankenbranche, im Jahr 2002 durchschnittlich 20 Prozent der Gesamtausgaben in die IT investiert [itopia, IT Cost Survey 2002/2003]. Immer öfter stellen große IT‐Projekte eine Herausforderung für die ganze Bank dar. So sind in IT‐Projekten interne Ressourcen neben dem Tagesgeschäft in erheblichem Maß gebunden. Darüber hinaus steigen Integrationsgrad und Verflechtungen der IT fortlaufend, womit die Interdependenzen zunehmen. Andererseits wächst aufgrund der steigenden Komplexität der Grad an isoliertem Fachwissen. Das Treffen von übergreifenden Entscheidungen wird immer schwieriger. Die erfolgreiche Durchführung von komplexen IT‐Projekten hat also für die Wettbewerbsfähigkeit und somit für die Zukunft einer Bank wesentliche strategische Bedeutung.
Methodological issues in a CMM Level 4 implementation
Authors: Antoniol Giuliano , Gradara Sara , Venturi Gabriele
Published: September 2004

The Capability Maturity Model (CMM) developed by the Software Engineering Institute is an improvement paradigm. It provides a framework for assessing the maturity of software processes on a five‐level scale and guidelines that help improve software process and artifact quality. Moving toward CMM Level 4 and Level 5 is a very demanding task even for large software companies already accustomed to the CMM and ISO certifications. It requires, for example, quality monitoring, control, feedback, and process optimization. In fact, going beyond CMM Level 3 requires a radical change in the way projects are carried out and managed. It involves quantitative and statistical techniques to control software processes and quality, and it entails substantial changes in the way the organization approaches software life cycle activities.

In this article, we describe the process changes, adaptation, integration, and tailoring, and we report lessons learned while preparing an Italian solution centre of EDS for the Level 4 internal assessment. The solution centre has about 350 people and carries out about 40 software development and maintenance projects each year. We describe how Level 4 Key Process Areas have been implemented, building a methodological framework, which leverages both existing available methodologies and practices already in place (e.g. derived form ISO compliance). We discuss how methodologies have been adapted to the company's internal and external situations and what are the underlining assumptions for the methodology adaptation. Furthermore, we discuss cultural and organizational changes required to obtain a CMM Level 4 certification. The steps and the process improvement we have carried out, and the challenges we have faced were most likely those with the highest risk and cost‐driving factor common to all organizations aiming at achieving CMM Level 4. Copyright © 2004 John Wiley & Sons, Ltd.
SPICE for small organisations
Authors: Tuffley Angela , Grove Bill , McNair Gary
Published: September 2004

There is a perception in small to medium software developers that international standards and process improvement models such as ISO/IEC 15504 are developed and are relevant only for large organisations. This paper discusses the results of a case study focusing on the conduct of a process improvement project in a small organisation, Mirrabooka Systems Pty Ltd. The project involved providing financial assistance, assessment services and process improvement mentoring to improve the capability of the organisation's software development processes. The activities centred around the provision of ISO/IEC 15504 conformant assessments, or more commonly known as SPICE Assessments, the results of which provided a basis for developing and implementing a process improvement programme for the organisation, which was implemented over a period of 18 months, and finally determining the improvements realised over that time frame. It discusses both the benefits and concerns Mirrabooka Systems Pty Ltd experienced by participating in the project and also demonstrates that ISO/IEC 15504 is not just suitable for large organisations but is also relevant and beneficial for small organisations. Copyright © 2004 John Wiley & Sons, Ltd.
An experience in using risk management in a software process improvement programme
Authors: Lassudrie Claire , Gullà‐Menez Gina
Published: September 2004

In the context of fierce competition in the field of Telecom Services, companies need to continuously improve their processes. To satisfy its business goals, centered on achieving enhanced customer satisfaction and greater competitiveness, France Telecom Research and Development (France Telecom R&D) set up a Software Process Improvement (SPI) programme in 1999. A risk management approach was used in this program to keep better control over its results.

This article describes the implementation of the Software Process Improvement Programme at France Telecom R&D, risk management implementation in the SPI programme and the results obtained from this approach. Copyright © 2004 John Wiley & Sons, Ltd.
Cortical dopamine D2receptors in type 1 and 2 alcoholics measured with human whole hemisphere autoradiography
Authors: Tupala Erkki , Hall Håkan , Halonen Pirjo , Tiihonen Jari
Published: September 2004

Alcoholism has been associated with lower density of striatal dopamine (DA) D2receptors, but there is much less data on cortical DA D2receptors. We evaluated the [125I]epidepride binding to DA D2receptors in Cloninger type 1 and 2 alcoholics and controls in frontal, temporal, and anterior cingulate cortices by using human postmortem whole hemispheric autoradiography, which provides high‐resolution images corresponding to positron emission tomographic (PET) studies. Type 1 alcoholics had lower and type 2 alcoholics had higher DA D2receptor density in all cortical areas compared to controls. Although the results did not reach statistical significance, the effect sizes were high. The DA D2receptor density in type 2 alcoholics decreased statistically significantly with age, and after correcting for age the binding values also fell below the level of controls. A statistically non‐significant tendency towards a decrease of cortical DA D2receptors was seen in controls, whereas in the type 1 alcoholic group no consistent correlation or even tendency towards increase with age was observed. Our results give preliminary evidence that DA D2receptors in cortical areas may be lower among both groups of alcoholics, but not necessarily of same magnitude as in subcortical structures. The rapid decline of cortical DA D2receptors among type 2 alcoholics may have some relevance to their antisociality, because this trait tends to diminish with age. The absence of correlation or even tendency towards increase of cortical DA D2receptors with age seen in type 1 alcoholics may give further evidence that they have a pre‐existing dopaminergic deficit. However, these results especially regarding aging effect must be considered as preliminary due to the different age‐range of type 2 alcoholics compared to two other groups. Synapse 54:129–137, 2004. © 2004 Wiley‐Liss, Inc.
Effects of birth insult and stress at adulthood on excitatory amino acid receptors in adult rat brain
Authors: El‐Khodor Bassem F. , Flores Gonzalo , Srivastava Lalit K. , Boksa Patricia
Published: September 2004

Birth complications involving fetal hypoxia and stress at adulthood, which are risk factors for schizophrenia, can produce alterations in subcortical dopamine (DA) function in rat models. As adults, rats born either by cesarean section (C‐section) or by C‐section with added global anoxia show increased stress‐induced DA release from nucleus accumbens and increased amphetamine‐induced locomotion, compared to vaginally born controls. Moreover, stress at adulthood interacts with these birth insults to modulate DA receptor and transporter levels. Glutamatergic transmission at the level of the nucleus accumbens, prefrontal cortex, and hippocampus are known to modulate subcortical DA activity. Thus, altered excitatory amino acid (EAA) function might contribute to the dopaminergic changes observed in rats after birth insult and/or stress at adulthood. To test this possibility, rats born vaginally, by C‐section, or by C‐section with 15 min of anoxia, were either repeatedly stressed (15 min of tail pinch daily for 5 days) at adulthood or received no stress, and levels of EAA receptor binding were measured by ligand autoradiography in limbic brain regions. As adults, rats born by C‐section showed increases in AMPA receptor binding in nucleus accumbens shell, NMDA receptor binding in cingulate cortex, and kainate receptor binding in the hippocampal CA1 region. Anoxic rats showed increases in CA1 kainate receptor and anterior olfactory NMDA receptor binding. Stress at adulthood increased AMPA receptor binding in several regions of prefrontal cortex and reduced NMDA receptor binding in infralimbic cortex and dentate gyrus, across all birth groups. Two instances of interactions between birth insult and stress at adulthood were observed. Stress reduced cingulate cortex NMDA receptor binding and increased olfactory tubercle kainate receptor binding only in C‐sectioned animals, but not in controls. The possibility that the observed EAA receptor changes contribute to dopaminergic dysfunction in these animal models is discussed, in light of known glutamate‐DA interactions. Synapse 54:138–146, 2004. © 2004 Wiley‐Liss, Inc.
L‐arginine increases dopamine transporter activity in rat striatum via a nitric oxide synthase‐dependent mechanism
Authors: Volz Trent J. , Schenk James O.
Published: September 2004

Literature reports suggest that nitric oxide (NO) participates in the regulation of dopaminergic neurotransmission, possibly through interaction with cysteine residues of the dopamine transporter (DAT). Rotating disk electrode voltammetry was used to measure dopamine (DA) transport in rat striatum to determine if 1) the nitric oxide synthase (NOS) substrate, L‐arginine (L‐Arg), could affect DAT activity; 2) L‐Arg‐dependent effects on DAT activity could be blocked by NOS and guanylate cyclase inhibitors, a NO scavenger, DA, and cocaine; 3) a NO donor could affect DAT activity; and 4) L‐Arg could protect the DAT from a sulfhydryl agent. L‐Arg increased DAT activity by increasing Vmax. NOS inhibitors (S‐ethylisothiourea and S‐isopropylisothiourea), a NO scavenger (2‐(4‐carboxyphenyl)‐4,4,5,5‐tetramethylimidazoline‐1‐oxyl‐3‐oxide), DA, and cocaine blocked the L‐Arg effect. The guanylate cyclase inhibitor, 1H‐(1,2,4)‐oxadiazolo[4,3a]quinoxalin‐1‐one, did not. The NO donor, S‐nitroso‐N‐acetylpenicillamine, decreased DAT activity and L‐Arg protected the DAT from the effects of the sulfhydryl agent N‐ethylmaleimide. These results suggest that L‐Arg, via NO, may play a role in regulating DAT activity in rat striatum by increasing the Vmax of DA transport. Furthermore, it is suggested that the effects of L‐Arg on DAT activity may be due to modification of the DAT itself, possibly via the NO‐mediated modification of DAT cysteine residues. Finally, NO produced from L‐Arg may affect the DAT differently than NO from NO donors. These results further the notion that dopaminergic neurotransmission may be regulated by changes in DAT activity caused by L‐Arg and NOS. Synapse 54:173–182, 2004. © 2004 Wiley‐Liss, Inc.
Schizosaccharomyces pombe ER oxidoreductin‐like proteins SpEro1a p and SpEro1b p
Authors: Kettner Karina , Blomberg Anders , Rödel Gerhard
Published: September 2004

Endoplasmic reticulum oxidoreductins (Ero proteins) are essential for oxidation of protein disulphide isomerase (Pdi), which introduces disulphide bonds in target proteins. Contrary to the situation in Saccharomyces cerevisiae, with a single Ero protein (Ero1p), the genomes of Schizosaccharomyces pombe and of humans encode two Ero‐like proteins. Here we show that both Sz. pombe proteins (SpEro1a p and SpEro1b p) are N‐glycosylated and firmly associated with membranes of the secretory pathway. Surprisingly, only expression of SpEro1b p completely restores growth of the temperature‐sensitive S. cerevisiae ero1‐1 mutant, whereas SpEro1a p only partially complements this mutation. Upon expression in S. cerevisiae wild‐type cells, SpEro1b p leads to a significantly increased resistance to reductive stress by dithiothreitol, whereas SpEro1a p has only a marginal effect. These data suggest that SpEro1b p is a functional homologue of the S. cerevisiae Ero1p. Copyright © 2004 John Wiley & Sons, Ltd.
Kluyveromyces lactis SSO1 and SEB1 genes are functional in Saccharomyces cerevisiae and enhance production of secreted proteins when overexpressed
Authors: Toikkanen Jaana H. , Sundqvist Lena , Keränen Sirkka
Published: September 2004

The SEB1/SBH1 and the SSO genes encode components of the protein secretory machinery functioning at the opposite ends, ER translocation and exocytosis, respectively, of the secretory pathway in Saccharomyces cerevisiae. Overexpression of these genes can rescue temperature‐sensitive (ts) growth defect of many sec mutants impaired in protein secretion. Furthermore, their overexpression in wild‐type yeast enhances production of secreted proteins in S. cerevisiae, which suggests that they may be rate‐limiting factors in this process. Here we report isolation of Kluyveromyces lactis homologues of these genes. KlSSO1 and KlSEB1 were isolated as clones capable of rescuing growth of ts sso2‐1 and seb1Δ seb2Δ sem1Δ strains, respectively, at the restrictive temperature. The encoded Kluyveromyces proteins are up to 70% identical with the S. cerevisiae homologues at the amino acid level and can functionally replace them. Interestingly, KlSSO1 and KlSEB1 show similar enhancing effect on production of a secreted protein as the SSO and SEB1 genes of S. cerevisiae when overexpressed. In accordance with the high homology level of the secretory pathway proteins in different yeast species, the polyclonal antibodies raised against S. cerevisiae Seb1p, Sso2p and Sec4p can detect homologous proteins in cell lysates of K. lactis and Pichia pastoris, the latter also in Candida utilis. The GenBank Accession Nos are AF307983 (K. lactis SSO1) and AF318314 (K. lactis SEB1). Copyright © 2004 John Wiley & Sons, Ltd.