bluuebunny/crossref_metadata_2025 huggingface dataset:
Performance evaluation of traffic models wherein two streams of nonrandom calls each having different multi‐slot call size are offered
Authors: Hayashi Zenji
Published: December 2002

With the sophisticated and diversified use of communications traffic, there has arisen a need for traffic evaluation of a model in which various nonrandom calls occur at different rates. From such a viewpoint, multitraffic evaluation is proposed. This is a method in which nonrandom calls are approximated by two Poisson call processes with different sizes, and the system is evaluated by a traffic model. This paper improves the conventional multitraffic evaluation and proposes a method that can evaluate a nonrandom mixed model with two kind of calls at different rates. The major points of improvement are as follows. (1) In the conventional method, only the properties of the calls immediately before call arrival are considered, while the proposed method considers the properties of the call to be evaluated immediately before arrival and the properties of other calls at arbitrary times. (2) The specification of various parameters in the multitraffic evaluation as well as the approximation accuracy are analyzed, and an adequate method of calculation is proposed. (3) It is shown that the approximation accuracy may be degraded, if based only on those two approaches, when there exist calls with a large variation coefficient. A means of remedy for such a situation is also presented. © 2002 Wiley Periodicals, Inc. Electron Comm Jpn Pt 2, 86(1): 47–63, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjb.10112
A sequence walking system for genome analysis
Authors: Miura Teruhisa , Takase Toshirou , Ishida Toru
Published: December 2002

With the development of the human genome analysis project, it is becoming possible to utilize large‐scale genome sequence data. One genome analysis method based on large‐scale sequence data is genome sequence walking. Applying sequence walking to the segment sequence database, it is possible to estimate the whole sequence of the gene to which the query sequence belongs by using the gene segment. By sequence walking, the researcher can estimate the genome sequence without going through biological experiments. This saves time and expense in sequence determination. Sequence walking has been performed using the well‐known BLAST. BLAST, however, is a tool based on similarity search, and is not adequate in sequence walking in which the same gene segments are connected, both from the viewpoint of efficiency and from the viewpoint of accuracy. In this study, it is shown that genome sequence walking is not a problem of similarity search, but is a string matching problem permitting error. A system dedicated to sequence walking is constructed by improving the string matching algorithm, which is more suited to sequence walking. The result has been publicized on the WWW. The proposed sequence walking system can realize sequence walking that is faster and more accurate than the conventional sequence walking by BLAST, thus reducing the burden on the researcher. © 2002 Wiley Periodicals, Inc. Electron Comm Jpn Pt 2, 86(1): 64–72, 2003; Published online in Wiley Interscience (www.interscience.wiley.com). DOI 10.1002/ecjb.10113
Design and realization of intelligent training system SmartTrainer
Authors: Jin Lai , Hayashi Yusuke , Ikeda Mitsuru , Mizoguchi Riichiro , Ohta Mamoru , Takaoka Yoshiyuki
Published: December 2002

Recently, demand for in‐house training systems has grown but the methodology remains unclear, and in most cases, development is left to individual experts. The authors proposed the intelligent training system SmartTrainer, with methodology being expressed in terms of ontology. SmartTrainer is a system that supports education and training of operators for service restoration after an accident at a power distribution substation; the cycle of training → knowledge acquisition → training is repeated through flexible use of a simulator. SmartTrainer provides teaching materials including operation‐related problem series (backbone stream), and teaching actions adjusted to the learner's response (rib stream). Rib stream is activated according to the learner's error pattern, while execution of teaching actions is controlled depending on the learner's data (e.g., learning history, enthusiasm). © 2002 Wiley Periodicals, Inc. Electron Comm Jpn Pt 2, 86(1): 73–83, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjb.10114
The effect of injection seeding on terahertz parametric oscillation
Authors: Imai Kazuhiro , Sugawara Satoshi , Shikata Junichi , Kawase Kodo , Minamide Hiroaki , Ito Hiromasa
Published: December 2002

We report on the use of injection seeding to narrow the terahertz‐wave linewidths of terahertz parametric light sources [a terahertz parametric generator (TPG) and a terahertz parametric oscillator (TPO)] using a LiNbO3 crystal and a Nd:YAG laser (wavelength 1.06 µm) as a pump light source. In this technique, the light of a Yb:fiber laser (wavelength 1.07 µm) operating in CW mode is injected into the LiNbO3 crystal, which brings about the narrowing of the terahertz‐wave spectral line. Our experiments confirm that injection seeding into the TPG not only narrows the terahertz‐wave spectral line but also greatly improves the input‐output characteristics. When we injection‐seeded a TPO pumped by light from a Nd:YAG laser with a single‐longitudinal‐mode spectrum, we obtained a 200‐MHz spectral line width, which approaches the Fourier‐transform limit. That is, our spectral linewidth was limited by the resolution of the measurement system. © 2002 Wiley Periodicals, Inc. Electron Comm Jpn Pt 2, 86(1): 26–35, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjb.1115
Actuator characteristic and electrode of multilayer piezoelectric ceramics
Authors: Terada Jiro
Published: December 2002

The topic of this research is the investigation of Ag‐Pd internal electrodes used to interconnect layers of multilayer actuator stacks. The layers are made of the piezoelectric ceramic material Pb(Zn1/3Nb2/3)0.125−Ti0.49Zr0.385O3 + MnO2 1.0 mass % + Al2O3 0.5 mass % (hereafter referred to as PZNTZ). It is found that when PZNTZ is added to the Ag‐Pd mixing powder in amounts greater than 0.1 mass %, the peeling strength of the electrodes is improved. The data reported here indicate that the addition of this material does not lead to large changes in the electrode resistance, and hence does not compromise its function. Two explanations are offered as to why the addition of PZNTZ produces this effect: first, it decreases the wetting of the electrode at the boundary between electrode and piezoelectric material; and second, it decreases the fluidity of the electrode material in the horizontal (surface) direction that accompanies shrinkage during sintering. When Ag‐Pd with PZNTZ added is used to make electrodes for the internal connections of a tuning fork consisting of multilayer piezoelectric ceramic material, and the tuning fork is driven under conditions that cause it to vibrate at the large amplitude of 25 µm, the tuning fork exhibits markedly superior linearity characteristics, including minimal changes in its resonance frequency. © 2002 Wiley Periodicals, Inc. Electron Comm Jpn Pt 2, 86(1): 36–46, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjb.1116
On the evaluation of performance of digital watermarking in the frequency domain
Authors: Ejima Masataka , Miyazaki Akio
Published: December 2002

With recent advances in digital technologies, it is now possible to access digital content and create copies easily. As a result, unauthorized copies are taken and the protection of copyright has become a problem. One of the solutions is electronic watermarking, for which various approaches have been proposed. However, since a method of evaluating the robustness of electronic watermarking methods has not been established, it is difficult to discuss superiority among the methods. In this paper, a method for evaluation of electronic watermarking methods using the frequency domain based on the operator representation of the image processing is proposed. By means of the proposed method, electronic watermarking schemes using discrete wavelet transform and discrete cosine transform are evaluated and the effectiveness of the proposed method is confirmed. © 2002 Wiley Periodicals, Inc. Electron Comm Jpn Pt 3, 86(4): 38–47, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjc.10013
Optimum design of multistage synchronous sampling rate converter
Authors: Asai Takahiro
Published: December 2002

This paper studies the optimum design of a multistage synchronous rate converter consisting of cascaded interpolation circuits by the window method. Two design approaches are proposed. One is a “simple design method” with a good perspective but a limited applicable range. The other is a “general‐purpose design method” that can be applied widely. In this paper, the former is mainly used. The signals are assumed to have a flat spectrum. As the cumulative product rule of the conversion error, the power sum is assumed. By providing the signal bandwidth, required conversion error, and total interpolation rate, optimum values are derived for the half width of the window in each stage and the interpolation rate that minimizes the number of multiplications and the interpolation coefficients. In the range where the “simple design method” is valid (where the signal bandwidth is relatively narrow), the optimum conditions for the number of calculations and for the total number of interpolation coefficients are the same. Then, the dependence of the number of calculations and the total number of interpolation coefficients as well as of the total interpolation rate and the total number of interpolation coefficients is found. A design example is presented. It is shown that highly accurate rate conversion is possible with few calculations. Further, according to the “general‐purpose design method,” it is possible to treat signals with a broad bandwidth (such as 0.92ϕ). © 2002 Wiley Periodicals, Inc. Electron Comm Jpn Pt 3, 86(4): 26–37, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjc.10015
Variable rate MPSK coded modulation using convolutional codes over modules
Authors: Konishi Tatsumi , Yokoyama Mitsuo , Uehara Hideyuki , Ito Hiro
Published: December 2002

This paper proposes variable rate MPSK coded modulation systems using convolutional codes over modules. First, we introduce the definition of the convolutional codes over modules and we illustrate the variable rate coded modulation systems. Next, we show that we can produce the best code for the minimum Hamming distance at any practicable rate, but we cannot get the best code for the minimum free Euclidean distance at any rate in the system. Moreover, we examine the performance in AWGN channels and in Rayleigh fading channels, and we present some properties of our systems. © 2002 Wiley Periodicals, Inc. Electron Comm Jpn Pt 3, 86(4): 20–25, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjc.10049
Robustness investigation of DCT digital watermark for printing and scanning
Authors: Mizumoto Tadashi , Matsui Kineo
Published: December 2002

This paper reports the effect of printing and scanning on digital watermarks for a hard copy image and investigates the necessary conditions for the watermark to be robust against the printing and scanning process. The effect of the printing and scanning process on the image content is presented first, and that on the Discrete Cosine Transform (DCT) domain is discussed next. Thus, we have necessary conditions for the watermark to be robust and present a sufficient condition to construct robust watermarking. It is realized by decreasing mutual interference between the embedded elements. This will enable us to make image content common to both the electrical nets and the physical nets. © 2002 Wiley Periodicals, Inc. Electron Comm Jpn Pt 3, 86(4): 11–19, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjc.10059
Realization of geometric illusions using a lateral‐inhibitive shifting model and intrinsic geometry of subjective visual space
Authors: Chao Jinhui , Miyata Yasuhito , Yoshida Shin'ichi , Suzuki Masaki , Kishigami Touru
Published: December 2002

A lateral‐inhibitive shifting model is proposed as a computational model of geometric illusions. This model is used to implement typical geometric illusions on a computer. Furthermore, this shifting model is used to naturally derive the Riemann metric and the Gaussian curvature distribution in the visual space as the psychological features for describing an optical illusion. ©2002 Wiley Periodicals, Inc. Electron Comm Jpn Pt 3, 86(4): 1–10, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjc.10060
Convolutional codes over rings for Rayleigh fading channels
Authors: Konishi Tatsumi , Yokoyama Mitsuo , Uehara Hideyuki , Ito Hiro
Published: December 2002

This paper presents a discussion on the convolutional codes over an integer residue ring ZM which are useful for MPSK coded modulation scheme in Rayleigh fading channels. When codes are constructed in Rayleigh fading channels, the most important criterion is the minimum Hamming distance of the codes. Hence, in this paper, a method is proposed to simply derive the convolutional codes over a ring with the largest minimum Hamming distance by using the nature of the ring. Further, the performance of the new codes derived by the proposed method is evaluated by theoretical analysis and simulation. It is shown that the derived codes have excellent performance in fast Rayleigh fading channels. Also, the performance of the codes is investigated in simple Viterbi decoding with the symbol distance expressed with one bit used in place of the Euclidean distance, in order to reduce the complexity of computation of Viterbi decoding. © 2002 Wiley Periodicals, Inc. Electron Comm Jpn Pt 3, 86(4): 48–54, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjc.1144
Method for solving nonlinear goal programming tasks with interval coefficients using GA
Authors: Taguchi Takeaki , Yokota Takao , Gen Mitsuo
Published: December 2002

In this study, the authors proposed a solution for directly using genetic algorithms without linear conversion for solving nonlinear goal programming problems involving interval coefficients. The proposed technique involves directly computing left‐side interval numbers in the goal constraint equation from the genetic algorithm solution and comparing their size with those of the right‐side numbers, for obtaining new difference variables. These difference variables vary depending on the goal type; they are defined using weights which express interval order evaluation criteria. In addition, as an example of application field for this method, the authors studied a large‐scale problem for optimal design of system reliability involving interval coefficients, in order to clarify localization of this method. © 2002 Wiley Periodicals, Inc. Electron Comm Jpn Pt 3, 86(4): 55–65, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjc.1145
Full motion compensation on subband domain
Authors: Ohta Mutsumi
Published: December 2002

This paper discusses motion compensation on the subband domain. A rigorous mathematical formula is derived that presents how the motion compensation on the full band signal can be expressed on the subband representation. In this way, it is found that the cross‐term filter must be introduced and the motion compensation concept, which have not been discussed, must be extended. This result is confirmed with video signal. It is found that MC similar to that on the full band can be carried out on the subband. The present research is expected to contribute to improvement of the efficiency of the layered video coding scheme. © 2002 Wiley Periodicals, Inc. Electron Comm Jpn Pt 3, 86(4): 66–74, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjc.1146
Performance evaluation of chip‐synchronous, code‐asynchronous optical CDMA systems for indoor infrared wireless communications with diffuse link
Authors: Satoh Takaaki , Hashimoto Takeshi
Published: December 2002

The transmission efficiency of optical CDMA is inferior to that of optical CSMA/CA, but it has the advantage of realizing indoor infrared wireless communication systems that are robust to sharp changes of the environment. However, intersymbol interference can easily be introduced into the indoor communication system by diffuse reflection, and its effect on optical CDMA systems may become a problem. In this paper, the bit error rate of optical CDMA using on‐off‐keying (OOK) and pulse position modulation (PPM) for optical orthogonal code and prime code is analyzed and the effects of intersymbol interference (ISI) produced by diffuse reflection links are investigated. © 2002 Wiley Periodicals, Inc. Electron Comm Jpn Pt 3, 86(4): 75–88, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjc.1147
Designing linear phase FIR digital filters with flat passband and equiripple stopband characteristics
Authors: Aikawa Naoyuki , Sato Masamitsu
Published: December 2002

It is known that linear phase FIR digital filters fall into four types considering the symmetry of impulse response. For example, filters of type 2 can be used at the time of partitioning and reconstruction of signals in multirate signal processing, and other types have similar special applications. Moreover, the linear phase FIR digital filters with flat passband and equiripple stopband characteristics are very important filters in practice because they have better time domain characteristics and less ringing than Chebyshev filters with equiripple stopband and passband characteristics. However, conventional design methods are restricted to type 1. In this paper, we therefore propose a method of design of linear phase FIR digital filters with flat passband and equiripple stopband characteristics for all four types. The proposed function is composed of two functions, one with a flat characteristic in the passband and the second with equiripple characteristics in the stopband. The latter function is obtained by using the well‐known Remez algorithm only for the stopband. © 2002 Wiley Periodicals, Inc. Electron Comm Jpn Pt 3, 86(4): 89–95, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjc.1148
The green polder model: institutionalizing multi‐stakeholder processes in strategic environmental decision‐making
Authors: Glasbergen Pieter
Published: December 2002

In many societies we observe a search for new institutional arrangements for dealing with strategic environmental issues. This paper discusses one of the first attempts to give environmental and nature conservation groups, alongside other public interest groups, a formal place in an early stage of political decision‐making. This so‐called green polder model is derived from experiences in the Dutch socio‐economic policy field and represents elements of a new political theory. The present author recognizes three alternatives in the debate about the green polder model. He analyzes two cases, which fit into the dominant pragmatic model. We can learn from the case studies about the scope, problems and opportunities of institutionalized multi‐stakeholder arrangements in environmental policy‐making. Copyright © 2002 John Wiley & Sons, Ltd. and ERP Environment.
The use of eco‐labels: a review of the literature
Authors: Galarraga Gallastegui Ibon
Published: December 2002

Labelling programs seek first to encourage a move towards more environmentally friendly consumption patterns, and second to induce productive structures, governments and other agents to increase the environmental standards of the products and services in the economy. This paper is devoted to revising the relevant literature on the issue. We divide the topic into three areas: (i) the study of demand, where most of the information available on the demand for labelled goods is presented; (ii) the study of supply, devoted to the analysis and summary of the information available in the literature and finally (iii) the market and trade impacts of labelling programmes, where the research carried out so far is carefully presented. The paper reveals the lack of proper and conclusive research to date, as well as the complexity of the topic of research. Copyright © 2002 John Wiley & Sons, Ltd. and ERP Environment.
IPPC and intensive pig production in England and Wales: compliance costs, emission abatement and affordability
Authors: Pellini Tiago , Morris Joe
Published: December 2002

EU Directive 96/61/EC on Integrated Pollution Prevention and Control (IPPC), for the first time, applies comprehensive environmental regulation to the intensive livestock sector. In this context, this paper assesses the impact of IPPC on the environmental and financial performance of intensive pig installations, using three case studies in England and Wales. Particular attention is paid to the impact of ‘best available techniques’ (BAT) and standard conditions of the permit on capital and operating costs, and on commercial viability. Key environmental and economic performance indicators are used to compare ‘with’ and ‘without’ IPPC situations.

The case studies confirm that IPPC will have greatest impact on animal housing and waste management systems. There are risks, however, that BAT prescriptions may not ensure a completely integrated approach to environmental protection throughout the whole production process. Furthermore, given the current depressed state of the sector, IPPC compliance could threaten the viability of existing production units. IPPC could, however, drive innovation and structural change in the pig industry. Copyright © 2002 John Wiley & Sons, Ltd. and ERP Environment.
Macrocyclic Melamine‐Based Ligand Complexes as Building Blocks for the Metal‐Directed Synthesis of Heterometallic Di‐ and Trinuclear Compounds
Authors: Comba Peter , Lampeka Yaroslaw D. , Lötzbeyer Lutz , Prikhod'ko Alexander I.
Published: December 2002

Heterodi‐ and heterotrimetallic NiII/CuII, Ni2II/CuII and NiII/Cu2II complexes of bis‐ and tris‐macrocyclic ligands, linked by a 1,3,5‐triazine spacer group, are obtained as products of copper(II)‐ or nickel(II)‐assisted condensations of the open‐chain tetraamine complexes [M2(2,3,2‐tet)]2+ [2,3,2‐tet= bis‐N,N′‐(2‐aminoethyl)propane‐1,3‐diamine, M2 = NiII or CuII] with formaldehyde and the monomacrocyclic ligand complexes [M1(L1)]2+, where L1 is a cyclam‐type macrocycle with a pendent melamine group (M1 = CuII or NiII). The spectroscopic (UV/Vis and EPR) and electrochemical properties of the oligonuclear heterometallic compounds in comparison with those of the homometallic analogues indicate small, but significant, intramolecular metal‐metal interactions. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
Vanadium‐Bromoperoxidase‐Mimicking Systems: Direct Evidence of a Hypobromite‐Like Vanadium Intermediate
Authors: Bortolini Olga , Carraro Mauro , Conte Valeria , Moro Stefano
Published: December 2002

Here we report a direct observation, by electrospray ionization mass spectrometry, of the intermediate [VO(OH2)(OH)(OBr)]+, which may be involved in the catalytic cycle of the V‐HalPO enzymes. Ab initio calculations also support the stability of such a species. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
Syntheses and Molecular Structures of Metallasiloxanes Containing Zn3O4 and Zn6Si6O10 Cores
Authors: Merz Klaus , Hu Huai‐Ming , Rell Stefan , Driess Matthias
Published: December 2002

The trinuclear zinc siloxane [(MeZn)2Zn(OSiPh3)4] (1) and the first novel siloxane‐bridged hexanuclear dimer [{Me(THF)Zn}2OZn(OSiR2)(R1)]2 (R = Ph, R1 = OSiR2OSiR2O) (2) are accessible by Brønsted acid/base reaction of triorganosilanols with the zinc base ZnMe2. Both compounds were characterised by NMR spectroscopy and a single‐crystal X‐ray structure analysis. The X‐ray structures of the reported complexes are discussed. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
Molecular Tectonics: Design of 1‐D Coordination Networks Based on Pyrene‐Bearing Pyrazolyl Units
Authors: Jouaiti Abdelaziz , Hosseini Mir Wais , Kyritsakas Nathalie
Published: December 2002

The synthesis of a new ligand based on a pyrene backbone bearing four pyrazolyl units is reported. Whereas this compound forms a discrete exo‐binuclear complex with palladium, in the presence of silver a 1‐D coordination network is obtained and structurally characterised in the solid state by X‐ray diffraction method. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
Symmetric Tetraalkynyldisilanes
Authors: Ackerhans Carsten , Roesky Herbert W. , Vidovic Denis , Magull Jörg
Published: December 2002

The reaction of the tetrachlorodisilane R2Si2Cl4 (1) [R = CH(SiMe3)2] with the lithium salt R*C≡CLi of the parent alkyne results in the replacement of the chlorine atoms with alkynyl groups to yield the product R2Si2(C≡CR*)4 [R* = Ph (2), tBu (3), SiMe3 (4), n‐C3H7 (5)]. Compounds 2 and 3 were characterized by X‐ray structural analysis. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
Preparation of the First Complexes of Bidentate Sulfimides; the X‐ray Crystal Structures of [PdBr2{1,4‐(PhS{NH})2C6H4}]2, [PdCl2{1,2‐(PhS{NH})(PhS)C6H4}] and trans‐[PdCl2{1,2‐(PhS{NH})(PhS)C6H4}PPh3]
Authors: Elsegood Mark R. J. , Holmes Kathryn E. , Kelly Paul F. , MacLean Elizabeth J. , Parr Jonathon , Stonehouse Julia M.
Published: December 2002

Reaction of [PPh4]2[Pd2X6] (where X = Cl, Br or I) with 1,4‐(PhS{NH})2C6H4 (1) in dichloromethane results in the formation of [Pd{1,4‐(PhS{NH})2C6H4}X2]2 (2). X‐ray crystallography (performed using a synchrotron source) confirms that in the case where X = Br (2a) both the bis‐sulfimides act as bridging ligands through N−Pd bonds producing an 18‐membered ring system linking the four sulfur atoms into an almost perfect square. Changing the reaction solvent to methanol/dichloromethane results in the formation of a polymeric material. Reaction of [PdCl2(PhCN)2] with 1,2‐(PhS{NH})(PhS)C6H4 (3) results in the formation of [PdCl2{1,2‐(PhS{NH})(PhS)C6H4}] (4) in which 3 acts as a bidentate ligand, bound by N−Pd and S−Pd bonds to form a unique MSCCSN metallacycle. The Pd−S bond is broken upon reaction with one equivalent of PPh3, generating trans‐[PdCl2{1,2‐(PhS{NH})(PhS)C6H4}PPh3] (5); further reaction with PPh3 results in complete removal of 3 from the system and formation of trans‐[PdCl2(PPh3)2]. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
Supramolecular Organisation of Polymeric Coordination Chains into a Three‐Dimensional Network with Nanosized Channels that Clathrate Large Organic Molecules
Authors: Zhang Xian‐Ming , Tong Ming‐Liang , Gong Meng‐Lian , Chen Xiao‐Ming
Published: December 2002

Hydrothermal treatment of a mixture of [Zn(MeCO2)2]·H2O, terephthalic acid, and 2,2′‐bipyridine resulted in a coordination polymer [Zn(bpy)(tp)](bpy) (1; bpy = 2,2′‐bipyridine, H2tp = terephthalic acid) which crystallizes in the monoclinic space group C2/c, Mr = 541.85, a = 15.388(11), b = 21.963(11), c = 7.670(8) Å, β = 112.82(2)°, V = 2387(3) Å3, Z = 4, Dc = 1.506 g·cm−3. An X‐ray single‐crystal structural analysis reveals that 1 is a three‐dimensional network with nanosized channels constructed from one‐dimensional coordination chains via C−H···O hydrogen bonds and aromatic intercalations. TGA and XRPD showed that the porous network of 1 is very stable while the guest 2,2′‐bipyridine molecules in the channels are removable. Compound 1 shows a strong ligand‐centred emission at room temperature in the solid state. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
Fluorinated 1,3λ4δ2,2,4‐Benzodithiadiazines − A Synthetic, Structural and Theoretical Study
Authors: Makarov Alexander Yu. , Bagryanskaya Irina Yu. , Blockhuys Frank , Alsenoy Christian Van , Gatilov Yuri V. , Knyazev Vladimir V. , Maksimov Alexander M. , Mikhalina Tatiana V. , Platonov Vyacheslav E. , Shakirov Makhmut M. , Zibarev Andrey V.
Published: December 2002

The series of title compounds has been prepared through both electrophilic (C6HnF5−n−N=S=N−SiMe3 + SCl2) and nucleophilic (C6HF4−S−N=S=N−SiMe3 + CsF) intramolecular ortho‐cyclisation reactions, and the former route seems to be the more effective. High regioselectivity of the ring‐closing procedures is observed in both cases. The compounds were characterised by X‐ray crystallography and multinuclear (1H, 13C, 15N and 19F) NMR spectroscopy. In accordance with GIAO calculations, 15N{1H} experiments and the effects observed on complete substitution of hydrogen by fluorine, the high‐field signal in the 15N NMR spectra can be assigned to N‐4 and the low‐field signal to N‐2. In the crystal, 5,6,7‐trifluoro‐ (5) and 5,6,8‐trifluoro‐1,3λ4δ2,2,4‐benzodithiadiazine (6) are planar, whereas the 6,8‐difluoro derivative 3 is bent along the S1···N4 line by 8.3°. According to NICS calculations the heterocycle moiety in this compound class is antiaromatic while the carbocycle is aromatic. The fluorine substituents increase the aromaticity − and in some cases (especially when a fluorine atom is present in the 8‐position) the antiaromaticity − of the corresponding rings. The ortho‐fluoro‐containing starting material C6HnF5−n−N=S=N−SiMe3 (n = 2: 10) cyclises to the fluorinated 2,1,3‐benzothiadiazole 27 upon treatment with CsF instead of SCl2. For starting compound 6‐HC6F4−S−N=S=N−SiMe3 (14) the planar (Z,E) configuration features a short intramolecular H···N contact, as evidenced by X‐ray diffraction. Both the reaction pathways mentioned are also discussed. (© Wiley‐VCH Verlag GmbH, 69451 Weinheim, Germany, 2003)
Synthesis, Structural Study, and In Vitro Trypanocidal and Antitumour Activities of Tetrakis(3‐methoxypropyl)tin and (3‐Methoxypropyl)tin Chlorides
Authors: Lébl Tomáš , Smička Aleš , Brus Jiří , Bruhn Clemens
Published: December 2002

A set of four water‐soluble (3‐methoxypropyl)stannanes of general formula (CH3OCH2CH2CH2)xSnCl4−x, where x = 4 (1), x = 3 (2), x = 2 (3), and x = 1 (4), was prepared. For 3 and 4, which were isolated in the crystalline state, it was shown by X‐ray diffraction that the tin atom is coordinated in distorted octahedral and trigonal‐bipyramidal geometries, respectively (i.e., the oxygen atoms of the 3‐methoxypropyl groups were coordinated to the central tin atom in both cases, forming chelates). For all compounds, structures in CDCl3 and [D6]DMSO solutions were proposed on the basis of their 13C and 119Sn NMR spectra. In CDCl3 solution, the degree of donor‐acceptor bonding between the central tin atom and oxygen atom of the 3‐methoxypropyl substituent was evaluated on the basis of 17O NMR chemical shifts and 3,6J(1H,119Sn) long‐range coupling constants. Compounds 2 and 3 exhibited promising in vitro antitumour and trypanocidal activities. (© Wiley‐VCH Verlag GmbH, 69451 Weinheim, Germany, 2003)
Synthesis, Crystal Structure, and Photophysical and Magnetic Properties of Dimeric and Polymeric Lanthanide Complexes with Benzoic Acid and Its Derivatives
Authors: Lam Alex Wai‐Hing , Wong Wing‐Tak , Gao Song , Wen Gehui , Zhang Xi‐Xiang
Published: December 2002

A new family of lanthanide carboxylate complexes with benzoic acid and its derivatives was synthesised and characterised. The structures of the complexes were established by X‐ray crystallography, which revealed that various chelating modes of the carboxylate ligands are present on the metal ion, resulting in the formation of dimeric and polymeric skeletons. The photophysical properties of the Eu and Tb complexes were studied: the complexes exhibited sensitised luminescence in the visible spectral region, but the luminescence intensities and lifetimes were very sensitive to quenching by the OH groups of methanol molecules. The solid‐state magnetic properties of the Gd and Tb complexes demonstrated the presence of weak antiferromagnetic exchange interactions at very low temperatures, caused by interaction between the neighbouring ions along the chain. (© Wiley‐VCH Verlag GmbH, 69451 Weinheim, Germany, 2003)
Anionic Cyclopentadienyl C60 Complexes of Molybdenum and Tungsten; The Strange Case of Iron
Authors: Thompson David M. , Jones Marni , Baird Michael C.
Published: December 2002

Thermal and photochemical reactions of the carbonylate salts A[(η5‐C5H5)Fe(CO)2], A[(η5‐C5H5)Mo(CO)3] and A[(η5‐C5H5)W(CO)3] (A = Na, PPN) in THF with C60 result in all cases in electron transfer to give [C60]− and the transient 17‐electron, metal‐centered radicals CpFe(CO)2, CpMo(CO)3 and CpW(CO)3, respectively. Subsequent self‐coupling of the three metal‐centred radicals then results in the formation of the metal‐metal bonded dimers [CpFe(CO)2]2, [CpMo(CO)3]2 and [CpW(CO)3]2. In contrast, while the mixture of Na[C60] and [CpFe(CO)2]2 does not react further under photochemical conditions, photolysis of mixtures of Na[C60] and both [CpMo(CO)3]2 and [CpW(CO)3]2 ultimately results in complete homolysis of the dimers and regeneration of the corresponding metal‐centered radicals, which then combine with the [C60]− remaining in solution to form the η2‐C60 complexes A[CpMo(CO)2(η2‐C60] and A[CpW(CO)2(η2‐C60]. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
Adsorptive Stripping Voltammetric Detection of Single‐Stranded DNA at Electrochemically Modified Glassy Carbon Electrode
Authors: Wang Huai‐Sheng , Ju Huang‐Xian , Chen Hong‐Yuan
Published: December 2002

Electrochemically modified glassy carbon electrode (GCE) was used to study the electrochemical oxidation and detection of denatured single‐stranded (ss) DNA by means of adsorptive stripping voltammetry. The modification of GCE, by electrochemical oxidation at +1.75 V (vs.SCE) for 10 min and cyclic sweep between +0.3 V and −1.3 V for 20 cycles in pH 5.0 phosphate buffer, results in 100‐fold improvement in sensitivity for ssDNA detection. We speculated that the modified GCE has a high affinity to single‐stranded DNA through hydrogen bond (specific static adsorption). Single‐stranded DNA can accumulate at the GCE surface at open circuit and produce a well‐defined oxidation peak corresponding to the guanine residues at about +0.80 V in pH 5.0 phosphate buffer, while the native DNA gives no signal under the same condition. The peak currents are proportional to the ssDNA concentration in the range of 0–18.0 μg mL−1. The detection limit of denatured ssDNA is ca. 0.2 μg mL−1 when the accumulation time is 8 min at open circuit. The accumulation mechanism of ssDNA on the modified GCE was discussed.
Iodide‐Selective Electrode Based on Copper Phthalocyanine
Authors: Shahrokhian Saeed , Taghani Abdollah , Moattar Fereidoon
Published: December 2002

Copper phthalocyanine was used as ion carrier for preparing polymeric membrane selective sensor for detection of iodide. The electrode was prepared by incorporating the ionophore into plasticized poly(vinyl chloride) (PVC) membrane, coated on the surface of graphite electrode. This novel electrode shows high selectivity for iodide with respect to many common inorganic and organic anions. The effects of membrane composition, pH and the influence of lipophilic cationic and anionic additives and also nature of plasticizer on the response characteristics of the electrode were investigated. A calibration plot with near‐Nernestian slope for iodide was observed over a wide linear range of five decades of concentration (5×10−6−1×10−1 M). The electrode has a fast response time, and micro‐molar detection limit (ca. 1×10−6 M iodide) and could be used over a wide pH range of 3.0–8.0. Application of the electrode to the potentiometric titration of iodide ion with silver nitrate is reported. This sensor is used for determination of the minute amounts of iodide in lake water samples.
Square‐Wave Voltammetry of Quasi‐Reversible CE Reactions at Spherical Microelectrodes
Authors: Garay Fernando , Lovrić Milivoj
Published: December 2002

A mathematical model for the CE mechanism in which the chemical together with the electrochemical reactions are quasi‐reversible at the surface of spherical macro and micro‐electrodes is presented for the case of square‐wave voltammetry. The analysis of voltammometric responses considers the influence of rate and equilibrium constants, together with the electrode radius, and their dependence on the square‐wave frequency (f). Both kinetics and the sphericity effect act synergistically on the electrochemical response. Also, the apparent electrode sphericity and the reversibility of the chemical as well as the electrochemical reactions are jointly affected by the variation of f. Disregarding the sphericity contribution in the calculation of kinetic parameters at a microelectrode may introduce errors even higher than one order of magnitude. The model allows the analysis of a more realistic and complex electrochemical system that requires not only the dependence of experimental responses on f, but also their fit with theoretical voltammograms, in order to provide some useful mechanistic information. Finally, concentration profiles are also studied to realize how the chemical contribution is buffering the absences of oxidized species at the electrode surface, and how those profiles are modified for the case of spherical macro and micro‐electrodes.
Electrical Control of Urease Activity Immobilized to the Conducting Polymer on the Carbon Felt Electrode
Authors: Uchiyama Shunichi , Kobayashi Masanao , Hasebe Yasushi
Published: December 2002

The activity of urease varies by its redox reaction. Active urease has an SH group that is essential to exhibit its activity, however, oxidation agents such as quinone compounds can oxidize the SH group in urease and a S–S bond is produced, resulting in the loss of enzyme activity. The reduction potential of cystine was almost the same as that of the recovery of urease activity. In this work, it has been found that the SH group of urease can be oxidized by not only chemical reaction but also by the direct electrode oxidation of urease and the produced S–S bond can be reduced to SH group by chemical and electrode reactions, and the original enzyme activity is recovered. This research shows that the regulation of urease activity is easily possible by changing the electrode potential of the porous carbon felt immobilized urease. The variation of urease activity was monitored by ammonia or carbon dioxide electrode equipped with the urease immobilized carbon felt, and the ammonia or carbon oxide generated from urea can transfer through the carbon felt to reach the each gas permeable membrane. The combination of gas electrode with porous conducting material such as carbon can supply the novel device for the electrochemical investigation of enzyme activity.
Study on the Electrochemical Behavior of Melatonin with an Activated Electrode
Authors: Xiao‐Ping Wu , Lan Zhang , Wen‐Rong Liao , Jian‐Ping Duan , Hong‐Qing Chen , Guo‐Nan Chen
Published: December 2002

It was found that melatonin could be incorporated and accumulated on the surface of the glassy carbon electrode which was activated electrochemically by pretreatment in sodium hydroxide solution by means of cycling the potential well into the positive limit of the solvent. In Britton‐Robinson buffer solution (pH 6.7), melatonin gave a sensitive oxidation wave at a potential of +0.65 V (vs.Ag/AgCl) by using Osteryoung square‐wave stripping voltammetry (OSWSV). The oxidation process has been shown to be irreversible and adsorption‐controlled at this electrode by means of cyclic voltammetry and linear sweep voltammetry. A chronocoulometric characterization of the adsorption characteristics of melatonin at this electrode is also presented. The factors affecting the peak current were optimized, and the dependence of peak currents on the concentration of melatonin was found to be linear in the range 8.0×10−7−1.0×10−5 mol L−1. A detection limit of 5.0×10−8 mol L−1 was obtained (signal‐to‐noise ratio of 3). This method was applied to the assay of melatonin in tablets and capsules with good recoveries (98–100%).
Rapid Detection of Vanillin in Alcoholic Beverages Using Stabilized Polymerized Lipid Film Based Biosensors
Authors: Nikolelis Dimitrios P. , Theoharis George
Published: December 2002

This work reports a technique for the rapid detection of vanillin in alcoholic beverages using stabilized lipid membrane based biosensors. Microporous filters composed of glass fibers (nominal pore sizes 0.7 and 1.0 μm) were used as supports for the polymerization of the lipid film and stabilization of these devices. The lipid film is formed on the filter by polymerization prior its use. Methacrylic acid was the functional monomer, ethylene glycol dimethacrylate was the crosslinker and 2,2′‐azobis‐(2‐methylpropionitrile) was the initiator. The response towards vanillin of the present stabilized lipid membrane biosensors composed of phosphatidylcholine was investigated. The stabilized lipid membranes provided artificial ion gating events in the form of transient signals and can be used again after storage in air. This has allowed the practical use of the technique for chemical sensing based on lipid film for the rapid detection of vanillin in wines and alcoholic beverages.
Cyclodextrin Modified Carbon Paste Based Electrodes as Sensors for the Determination of Carcinogenic Polycyclic Aromatic Amines
Authors: Ferancová Adriana , Korgová Elena , Labuda Ján , Zima Jiří , Barek Jiří
Published: December 2002

Voltammetric properties and possibility of the determination of carcinogenic aminoderivatives of polycyclic aromatic hydrocarbons, namely 1‐ and 2‐aminonaphthalene and 2‐aminobiphenyl, have been investigated. Carbon paste electrodes (CPE) modified with monomeric α‐, β‐ or γ‐cyclodextrin and carbon‐based screen‐printed electrodes (SPE) surface‐modified with a thin film of β‐cyclodextrin (β‐CDP) or carboxymethylated β‐cyclodextrin (β‐CDPA) condensation polymer were used for that purpose as simple electrochemical biosensors. Analytical procedure for the DPV determination of tested amines using these biosensors was proposed. Linear calibration plots within the concentration range of 2×10−8 – 2×10−7 mol dm−3 and 2×10−7–1×10−6 mol dm−3 with limits of quantification of the order of 10−9 mol dm−3 were obtained for the modified CPE and modified SPE.
Catalysis‐Electrochemical Detection of Horseradish Peroxidase at Zeptomole Level in Capillary Zone Electrophoresis
Authors: He Zhihui , Wang Haiyan , Sun Xuemei , Jin Wenrui
Published: December 2002

Capillary zone electrophoresis with catalysis‐electrochemical detection has been developed and applied to determining horseradish peroxidase (HRP) at zeptomole levels. In this method, an on‐line enzyme catalysis reactor with a reaction capillary was designed. Isoenzymes of HRP were separated by capillary zone electrophoresis, and then they catalyzed the enzyme substrate 3,3′,5,5′‐tetramethylbenzide (TMB(Red)) and H2O2 in the reaction capillary. The reaction product, TMB(Ox), could be determined using amperometric detection on a carbon fiber microdisk bundle electrode at the outlet of the reaction capillary. Because of enzyme amplification, a significant amount of TMB(Ox) could be produced for detection. Therefore, the limit of detection (LOD) of HRP is very low. The optimum conditions of the method are 1.5×10−2 mol/L borate (pH 7.4) for the run buffer, 2×10−3 mol/L for the concentration of H2O2, 2×10−4 mol/L TMB(Red)+2.0×10−2 mol/L citrate‐phosphate (pH 5.0) for the substrate solution, 40 cm for the liquid pressure height, 20 kV for the separation voltage, 100 mV for the detection potential. HRP could be measured with a detection limit of 4.8×10−12 mol/L or 47.5 zmol (S/N=3). The linear range is from 2.40×10−11 to 2.40×10−8 mol/L. Using this method, commercial HRP was measured at zeptomole within ten minutes.
Label‐Free and Label Based Electrochemical Detection of Hybridization by Using Methylene Blue and Peptide Nucleic Acid Probes at Chitosan Modified Carbon Paste Electrodes
Authors: Kara Pinar , Kerman Kagan , Ozkan Dilsat , Meric Burcu , Erdem Arzum , Nielsen Peter E. , Ozsoz Mehmet
Published: December 2002

A chitosan modified carbon paste electrode (ChiCPE) based DNA biosensor for the recognition of calf thymus double stranded DNA (dsDNA), single stranded DNA (ssDNA) and hybridization detection between complementary DNA oligonucleotides is presented. DNA and oligonucleotides were electrostatically attached by using chitosan onto CPE. The amino groups of chitosan formed a strong complex with the phosphate backbone of DNA. The immobilized probe could selectively hybridize with the target DNA to form hybrid on the CPE surface. The detection of hybridization was observed by using the label‐free and label based protocols. The oxidation signals of guanine and adenine greatly decreased when a hybrid was formed on the ChiCPE surface. The changes in the peak currents of methylene blue (MB), an electroactive label, were observed upon hybridization of probe with target. The signals of MB were investigated at dsDNA modified ChiCPE and ssDNA modified ChiCPE and the increased peak currents were observed, in respect to the order of electrodes. The hybridization of peptide nucleic acid (PNA) probes with the DNA target sequences at ChiCPE was also investigated. Performance characteristics of the sensor were described, along with future prospects.
Differential Pulse Voltammetric Simultaneous Determination of Four Anti‐Inflammatory Drugs by Using Soft Modelling
Authors: Reguera Celia , Ortiz M. Cruz , Arcos M. Julia
Published: December 2002

An application of a partial least squares calibration method for the simultaneous voltammetric determination of indomethacin, acemethacin, piroxicam and tenoxicam is suggested. It was shown that it is possible to resolve complex mixtures of analytes even when they have strongly overlapped signals. In order to check the proposed method, statistical analysis of the results was performed by mean of hypothesis tests. The method developed was applied to the electrochemical reduction region of four anti‐inflammatory drugs and allowed the drugs to be quantified at concentrations between 0.52 and 4.09 μg mL−1 for acemethacin, 0.44 and 3.50 μg mL−1 for indomethacin, 0.43 and 3.40 μg mL−1 for piroxicam, and 0.42 and 3.30 μg mL−1 for tenoxicam with good results. The average absolute value of relative errors was 2.25%, 4.31%, 1.68% and 2.49%, respectively.
A Study on Operational Parameters for Advanced Use of Bismuth Film Electrode in Anodic Stripping Voltammetry
Authors: Hočevar Samo B. , Ogorevc Božidar , Wang Joseph , Pihlar Boris
Published: December 2002

A study is presented on the characterization, evaluation and optimization of several key operational parameters for a reliable and effective use of a bismuth film electrode (BiFE) as an advanced replacement of the mercury film electrode in anodic stripping voltammetric measurements of trace heavy metals. Applying in situ preparation of the BiFE and employing lead(II) and cadmium(II) as model analyte ions, key parameters including bismuth precursor salt and substrate surface (platinum, gold, glassy carbon, carbon paste, carbon fiber) for bismuth plating, concentration as well as cationic and anionic composition of the measurement solution, solution pH and temperature, potential interferents, and stripping modes were carefully examined for their effects in the preconcentration and stripping steps. Parameters such as substrate surface (except platinum), precursor salt, solution matrix and temperature showed no or little impact on the BiFE performance in stripping analysis. On the other hand, the BiFE performance was found to be dependent on the solution pH (with maximum efficiency in the range of 4 to 5), on the stripping mode (with square‐wave voltammetry as the best choice) and to a certain degree on the presence of surface active substances. The results revealed that the non‐toxic solid‐state BiFE is applicable under a wide variety of conditions which proves it highly suitable for practical work in environmental trace heavy metal analysis.