bluuebunny/crossref_metadata_2025 huggingface dataset:
Pulse generator based on commercially available digital circuitry
Authors: Chang K. C. , Mias C.
Published: March 2007

The circuitry of a low cost pulse generator based on a commercially available digital integrated circuit is presented. The circuit produces ‘rectangular’ pulses of amplitude 0.77 V and width 362 ps at half amplitude, and 0.688 V peak‐to‐peak monocycle pulses with a −10 dB bandwidth of 1.2787 GHz (0.1191 to −1.3978 GHz). © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 1422–1427, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22425
Dual‐frequency antenna for RFID tags with complementary characteristic
Authors: Kuo Jieh‐Sen , Wang Jyun‐Jie , Huang Chih‐Yu
Published: March 2007

A novel dual‐frequency Radio Frequency Identification (RFID) antenna with complementary operation mechanisms (two different operation mechanisms: near field and far field operation) is proposed. The proposed antenna is obtained by printing a rectangular‐spiral‐shaped and a meander‐shaped line, which is placed above on a rectangular microwave substrate as a RFID tag's antenna where its ground plane is at the bottom of substrate. The proposed antenna is fed by a 50 Ω microstrip line printed on the same substrate, and the antenna's two resonant frequencies can be excited with good impedance matching. Closer to omni‐directional radiation patterns and the lower cross‐polarization levels (at least 25‐dB) are also obtained. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 1396–1398, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI.10.1002/mop.22426
Left‐handed microstrip lines with multiple complementary split‐ring and spiral resonators
Authors: Crnojević‐Bengin V. , Radonić V. , Jokanović B.
Published: March 2007

Negative‐permeability sub‐wavelength particles, namely split‐ring resonators and spiral resonators, are compared and their performances analyzed for a different number of concentric rings and spiral turns, respectively. Left‐handed lines are designed, fabricated, and measured that use multiple complementary split‐ring and spiral resonators. More compact structures are obtained, with improved characteristics. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 1391–1395, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI.10.1002/mop.22427
Design of a compact rectangular mono‐cone antenna for UWB applications
Authors: Choi Il H. , Choi Sang S. , Park Jong K. , Song Hyo W. , An Hee S.
Published: March 2007

In this articel, we have designed, fabricated, and measured a compact rectangular mono‐cone antenna for UWB applications. The measured bandwidth is 8.2 GHz from 2.8 GHz to 11 GHz for S11< −10 dB. The path loss S11and phase were measured and discussed. The radiation patterns and antenna gain across the frequency bands are also presented. From the measured results, the proposed antenna shows a good characteristic (almost linear phase, omni‐directional pattern, and very low gain variation). © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 1320–1323, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22430
A hybrid FDTD/UTD radiowave propagation modeling: Application to indoor channel simulations
Authors: Reynaud Sébastien , Vauzelle Rodolphe , Reineix Alain , Guiffaut Christophe
Published: March 2007

Classical theories such as the uniform theory of diffraction use analytical expressions for diffraction coefficients. These methods are convenient for canonical problems and objects much greater than the wavelength and enable to rise in frequency. For more complex and smaller scattering structures, rigorous methods as the finite difference time domain method is more suited. In this article, we present a new look on radiowave propagation prediction, combining the advantages of these two complementary methods. This article presents several studies aiming to evaluate the validity domain of this hybrid method in terms of far‐field propagation conditions. Finally, an application to indoor channel modeling is presented. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 1312–1320, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22431
Design of a V‐shaped surface‐mounted monopole array antenna for DCS/PCS operations
Authors: Floc'h Jean‐Marie , Rmili Hatem
Published: March 2007

In this paper, a surface‐mountable, reconfigurable monopole antenna was designed for array antenna operations in the DCS‐1800 and PCS‐1900 bands. First, the elementary structure was obtained by folding a metallic strip into a V‐shape, and then soldered to a 50‐Ω microstrip feed line printed on a metallized substrate. For the optimized structure, an impedance bandwidth of 22.7%, corresponding to the frequency range 1560–1960 MHz, was obtained. Measured radiation patterns are similar to that of a monopole antenna, and the maximum measured gain is about 1.8 dBi at 1.6 GHz. Next, this elementary antenna was used for realization of both linear‐ and planar‐array antennas. The linear‐array shows a dual and wideband behavior with good impedance matching and asymmetric radiation patterns, whereas the planar‐array presents a unique resonant band with moderate adaptation and symmetric radiation patterns. The measured gain for the two arrays is about 5 dBi. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 1486–1491, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI.10.1002/mop.22437
Remote optically controllable antenna array using a single optical fiber for RoF reception
Authors: Ritosa P. , Vidmar M.
Published: March 2007

A novel technique for remote antenna array steering and control using a single optical fiber is described. The system is designed to be combined with radio‐over‐fiber (RoF) transmission of medium range (10–30 km) on standard G.652 optical fiber using standard optical components. System characteristics and performance are presented. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 1349–1353, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22444
Doppler‐invariant pulse compression for targets moving in an arbitrary direction
Authors: Yang J. , Sarkar T. K.
Published: March 2007

It can be shown that a hyperbolic frequency‐modulated waveform is Doppler‐invariant only when the Doppler factor is a constant number, i.e., the target has a constant velocity and along the direction from the radar to the target. If the target moves in an arbitrary direction, the degradation of the pulse compression caused by the mismatch between the reflected signal and the matched filter may still exist. In this paper, we demonstrate that the Doppler effect caused by the moving target in an arbitrary direction can be approximated by a target with an initial velocity and a constant acceleration along the direction from the radar to the target, which results in a frequency shift in the reflected waveform. Therefore, a bank of matched filters with preselected values of frequency shifts can be utilized to compensate for the Doppler effect. Numerical examples, with target moving in an arbitrary direction, are presented to illustrate this effect, which has been successfully compensated by shifting the frequency response of the matched filter. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 1449–1453, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI.10.1002/mop.22454
Wideband microstrip‐fed planar monopole antenna
Authors: Tseng Ching‐Fang , Huang Cheng‐Liang
Published: March 2007

The design of a multiband planar monopole antenna with a RF/battery shielding metal case is described. The prototype of the proposed antenna with 0.8 mm in height and 50 mm in length has been fabricated. The proposed antenna exhibits sufficient bandwidth of 915 MHz (1525–2440 MHz) with a voltage standing wave ratio (VSWR) lower than 2:1, which covers global positioning system (1575.42 MHz), digital communication system (1710–1880 MHz), personal communication service (1850–1990 MHz), universal mobile telecommunications system (1920–2170 MHz), and International Mobile Telecommunications‐2000 (1900–2025 MHz) bands. At the upper band, the measured impedance bandwidth (2:1 VSWR) of the designed antenna is about 770 (4310–5080 MHz) MHz. This antenna could be applicable for the mobile communication systems. Details of the proposed antenna design and the experimental results are presented and discussed. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 1377–1383, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI.10.1002/mop.22458
Novel distributed circuit model for transition between coplanar waveguide and microstrip by using the generalized telegrapher equation method
Authors: Hong Jing‐song , Zhang Guang‐Ming , Wang Bing‐Zhong
Published: March 2007

In this article, a novel distributed circuit model of coplanar waveguide to microstrip (CPW‐M) transition is presented by using generalized telegrapher equation. In comparison with conventional nonuniform transmission line equation, the generalized telegrapher equation has two additional terms, dependent series voltage and shunt current sources, which represent local radiation effect from discontinuities of the nonuniform transmission line itself. Based on the full‐wave numerical results, the distributed circuit parameters can be extracted by using the generalized telegrapher equation. Since the generalized telegrapher equation coefficients are determined by dynamic numerical methods and the coefficients are invariant with the line excitation and load, the equation is dynamical rather TEM. The numerical experiments show that the novel distributed circuit model for this CPW‐M transition can have broadband characteristics. As a preparatory experiment, an improved CAD method using this model is utilized to model different structures of CPW‐M transition. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 1323–1328, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22461
A coupling element‐based quad‐band antenna structure for mobile terminals
Authors: Villanen Juha , Icheln Clemens , Vainikainen Pertti
Published: March 2007

A novel internal coupling element‐based antenna structure for quad‐band mobile terminals is presented. The antenna structure comprises of two nonresonant coupling elements, a multi‐resonant matching circuitry, and the chassis of the mobile terminal. The coupling elements occupy an extremely low volume of only 0.7 cm3, and they have a very low profile of only 4 mm. Despite of the low volume and low profile of the antenna structure, it can fulfill the bandwidth requirements of the GSM850/900 and GSM1800/PCS1900 systems with sufficiently high efficiency, thus making it a promising antenna candidate for future mobile terminals. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 1277–1282, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22463
Dual bandstop resonator using combined split ring resonator and defected ground structure
Authors: Safwat Amr M. E. , Tretyakov Sergei , Räisänen Antti
Published: March 2007

Defected ground structure and split ring resonator are combined to form a compact dual bandstop filter or a dual pole bandstop filter. An equivalent circuit model is developed for the proposed structure and it agrees very well with EM simulation. A dual bandstop resonator was fabricated. Measurements and theoretical predictions are in a very good agreement. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 1249–1253, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22464
Ultra wideband folded rectangular monopole
Authors: Thomas K. George , Lenin N.
Published: March 2007

This article describes a folded planar rectangular monopole antenna, which has reasonably low profile and extremely wide impedance bandwidth. A simple formula is also suggested to determine the frequency of the operation of planar structures, in general. Details of the experimental and simulation results for the proposed antenna are examined and analyzed. Impedance characteristics of simple folded and planar configurations of varied dimensions are presented. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 1497–1500, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI.10.1002/mop.22466
Analyzing longitudinal‐mode of single‐frequency ring fiber laser
Authors: Wang T. S. , Guo Y. B. , Wang K.
Published: March 2007

To realize single‐frequency of the fiber laser, a ring configuration is devised. The single‐frequency operation is realized at 1549.63 nm by using a fiber Bragg grating (FBG) as wavelength‐selective element and a unpumped 1.5 m‐long erbium‐doped fiber, which can produce standing‐wave saturation effects in the cavity. A measurement method based on fiber‐coupling scanning Fabry–Perot (F‐P) interferometer at 1.55 μm is designed. The laser longitudinal‐mode spacing is 11.1 MHz. The single‐frequency is observed by the interferometer with free spectrum range (FSR) of 7.5 GHz. The longitudinal‐mode fabric is analyzed by the interferometer with FSR of 1.5 GHz. As the cavity length increases, the longitudinal‐mode spacing changes to 3.7 MHz. The structures of longitudinal‐modes under different cavity lengths are compared. The longitudinal‐mode linewidth of 20 MHz is measured. Experimental results show that single‐frequency of the fiber laser can be approved accurately, and the effectiveness of the method, which can analyze longitudinal‐mode of the fiber laser with scanning Fabry–Perot (F‐P) interferometer, is improved. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 1494–1497, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI.10.1002/mop.22467
Design of a UWB planar 180° hybrid exploiting microstrip‐slot transitions
Authors: Abbosh A. M. , Bialkowski M. E.
Published: March 2007

The article describes the design of a planar 180° hybrid with an ultra wideband (UWB) performance. The device employs two substrates with a common ground plane and various microstrip‐slot transitions to achieve in‐phase and out‐of‐phase signal division over an ultra wide frequency range. At the initial stage, simple design guidelines are used but the final dimensions are determined using a full‐wave analysis and design software package. The simulated and measured results of the proposed device reveal a well balanced power split accompanied by a very good approximation of ideal 180° and 0° differential phase shift across the band 3.1 to more than 11 GHz. Also low insertion losses, good return loss at all of the four ports, high isolation between the input ports and fine isolation between output ports are noted across this frequency band. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 1343–1346, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22472
Neural models for the V‐shaped conductor‐backed coplanar waveguides
Authors: Guney Kerim , Yildiz Celal , Kaya Sabri , Turkmen Mustafa
Published: March 2007

Neural models based on the artificial neural networks (ANNs) for computing the effective permittivities and characteristic impedances of V‐shaped conductor‐backed coplanar waveguides are presented. The proposed neural models can also be used for calculating the characteristic parameters of conductor‐backed coplanar waveguides. Six learning algorithms, Levenberg–Marquardt, bayesian regularization, quasi–Newton, scaled conjugate gradient, conjugate gradient of Fletcher‐Reeves, and resilient propagation, are used to train the ANNs. The neural results are in very good agreement with the results available in the literature. When the performances of neural models are compared with each other, the best result is obtained from the ANNs trained by the LM algorithm. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 1294–1299, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22473
Investigation of the performance of L‐band EDFAS with single forward pumping schemes
Authors: Liang Tsair‐Chun , Huang Hsi‐Shan
Published: March 2007

In this article, the authors investigate and compare the gain and noise figure of various 1480‐nm pumping erbium‐doped fiber amplifier configurations to amplify 32 digital wavelength division multiplexing channel signals operated in the long‐wavelength band of 1570–1610 nm. It was found that the two‐stage designs are better than one‐stage design to offer the higher output power and gain with moderate low noise figure in single forward pumping scheme. Especially, the two‐stage double‐pass configuration, Type A, provides gain enhancement more than about 5.4 dB without paying any noise penalty. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 1259–1261, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22475
Solid‐state 13C NMR and quantum chemical investigation of metal diene complexes
Authors: Ma Zhiru , Facelli Julio C. , Pugmire Ronald J. , Dunn Brian C. , Turpin Gregory C. , Eyring Edward M. , Ernst Richard D.
Published: March 2007

This paper presents novel measurements and calculations of the olefinic 13C chemical shift tensor principal values in several metal diene complexes. The experimental values and the calculations show shifts as large as 70 ppm with respect to the values in the parent olefinic compounds. These shifts are highly anisotropic, with the largest ones observed in the less shielded principal components and the smallest ones in the most shielded principal components of the tensor. The orientations of the principal components of the tensors remain, within 10°, at their directions in ethylene and other olefinic compounds. The calculations, performed using the GIAO method and the LanDZ pseudopotential basis set, show good agreement with the experiments, and were used to establish definite evidence for the existence of a Cl‐bridge structure in the bicyclo[2.2.1]hepta‐2,5‐diene (BCHD)dichlororuthenium(II) polymer. Copyright © 2007 John Wiley & Sons, Ltd.
Two‐dimensional spectroscopy with parallel acquisition of 1HX and 19FX correlations
Authors: Kupče Eriks , Cheatham Steve , Freeman Ray
Published: March 2007

Two‐dimensional NMR spectra correlating both 1H and 19F nuclei with either 13C or 15N, are recorded at the same time, using a 600‐MHz broadband radio frequency probe feeding independent 1H and 19F receiver channels. This technique, known as parallel acquisition NMR spectroscopy (PANSY), speeds up multidimensional NMR and is compatible with other fast‐acquisition schemes. The method is illustrated with single‐bond (HSQC) and multiple‐bond (HMBC) experiments on 2‐bromophenyl‐3‐trifluoromethyl‐5‐methylpyrazole, giving simultaneous 1HX and 19FX correlation spectra (X = 13 C or 15N). Copyright © 2007 John Wiley & Sons, Ltd.
Machiavelli, marketing and management: ends and means in public affairs
Authors: Harris Phillip
Published: March 2007

Niccolo Machiavelli is introduced and used as a guide to some of the key issues facing modern business and government. Machiavelli's morality and philosophy is explored and reflected upon. Insights into the realities of power and decision making are used to reflect on the emergence of the modern public affairs industry. Key lessons are suggested for success.

Copyright © 2007 John Wiley & Sons, Ltd.
Lobbying and the 2006 U.S. midterm elections
Authors: McGrath Conor
Published: March 2007

Lobbyists are inextricably intertwined with the electoral process in the United States, but rarely have they ever featured so prominently in an election year as in 2006. The midterm elections came at the end of a year in which the political news was often dominated by stories of lobbying scandal, most notably that involving Jack Abramoff. Lobbying was an important issue in many peoples' voting decisions, and moreover one of the immediate outcomes of the election was a raft of lobbying reform measures both in Congress and in the individual states. As one commentator put it: ‘For lobbyists, 2006 rolled by like a late‐night B movie where the earthquake wipes out the villagers who refused to heed the warning signs’ (Divis, 2006). This article reviews some of the most substantial lobbying scandals which emerged during 2006, considers how lobbying and lobbyists fared during the election campaigns, and analyses the various reforms which have recently been considered and implemented, before briefly examining how lobbyists will impact upon the 2008 election races.

Copyright © 2007 John Wiley & Sons, Ltd.
Analysis of heterogeneity by sedimentation transport: Concentration and pressure effects
Authors: Atkinson Carole M. L. , Dietz Roy
Published: March 2007

A new approach to the pressure dependence of sedimentation was applied to polystyrene in cyclohexane under conditions, below the theta‐temperature, where the concentration dependence is small. An expression for the distribution of sedimentation coefficient was derived, and used to find molecular weight distributions of standard samples; comparisons were made with molecular weight distributions found independently.
Factors affecting the elimination of hydrogen fluoride from a vinylidene fluoride/hexafluoropropene/tetrafluoroethylene terpolymer
Authors: Wright W. W.
Published: March 2007

The evolution of hydrogen fluoride from a vinylidene fluoride/hexafluoro‐propene/tetrafluoroethylene elastomer has been studied over the temperature range 200–275 °C in air. The rate of evolution is affected by the diamine curing agent, the carbon black filler and the acid acceptor used and their effects are interrelated. The acid acceptor also influences the crosslink density attained in the curing process. It was found that some metallic hydroxides and carbonates, in whose presence an acceptable level of crosslinking was achieved, were some 50 to 100 times more efficient than the magnesium oxide normally used in reducing the rate of hydrogen fluoride evolution.
Kinetic study of the formation of 1,1‐Diphenyl ethylene dimer dianions
Authors: Adams David J. , Clifton James , Gordon Manfred , Iguchi M.
Published: March 2007

The reaction between styrene or a styrene derivative and an alkali metal is the first stage in the synthesis of regular copolymers. The kinetics of the reaction of 1,1‐diphenyl ethylene in tetrahydrofuran at a sodium metal surface has been studied using a rotating sodium disc. It has been established that the reaction is transport controlled and first order in 1,1‐diphenyl ethylene concentration.
Correlation between morphology and stress—strain properties of three block copolymers i. stress‐softening effect
Authors: Pedemonte Enrico , Turturro Antonio , Dondero Giovanni
Published: March 2007

The stress‐softening effect, which comes out when SBS three block copolymers are stretched, is taken into consideration and the conclusion is reached that it is due to a disruption of the polystyrene continuous phase, according to the hypothesis of other authors. This conclusion is supported by two kinds of experiments performed on samples having a well known and simple morphology. First of all by stress‐strain measurements on specimens previously swollen: it can be seen that the stress‐softening effect disappears as soon as the structure of the material is completely modified by the treatment. Secondly by the direct observation at the electron microscope of the structure after the deformation. This shows how the original continuous and regular polystyrene rods of the “single crystal” assume a string of pearl structure which finally is irreversibly disrupted.
Experiences with the method of trimethylsilylation for the study of soluble silicates
Authors: Glasser Lesley S. Dent , Sharma Santosh K.
Published: March 2007

It is possible to prepare organic derivatives of silicate groups in which each terminal oxygen is blocked by a trimethylsilyl group. This can provide a route for the preparation of new polymers. It can also provide information about the structure of the original silicate group, provided that this is faithfully reflected in the structure of the derivative. This will be true only if the silicate groups do not undergo any polymerisation, depolymerisation or rearrangement while the derivatives are being formed.

The method has previously been successfully applied to a wide variety of silicates; this paper describes, in particular, attempts to apply it to the study of sodium silicates. An assessment is given of the difficulties involved and of the utility of the method for this type of study.
Titration curves of p‐hydroxybenzoic acid/formaldehyde/p‐bromophenol copolymers
Authors: Chatterjee S. K. , Dattagupta N.
Published: March 2007

Copolymers obtained by the condensation of p‐hydroxybenzoic acid, p‐bromophenol, and formaldehyde showed characteristic titration curves in non‐aqueous media. The titration curves indicated a series of breaks which bear integral relations to each other. These features have been interpreted in terms of homoconjugation, intramolecular hydrogen bond formation, and composition of the copolymers.
Phosphorescence from commercial polyolefins and polyamides: Effects of thermal and photochemical oxidation
Authors: Allen N. S. , Homer J. , McKellar J. F. , Phillips G. O.
Published: March 2007

A study of the phosphorescence emission from the commercial polyolefins, polyethylene, polypropylene and poly‐4‐methylpentene‐1 and the polyamides, nylon 6/6, 6, 11 and 12 is presented and the origin of the emission discussed. Impurity centres in the polymer are responsible for the emission, being present either as groups directly attached to the polymer backbone or as discrete molecules within the polymer matrix. These impurities can play an important part in the thermal and photochemical oxidation of the polymer. Therefore, changes in the phosphorescence spectra can provide valuable information on the mechanisms of both degradation processes.
Crosslinking of latex polymers
Authors: Yeliseeva Valentina I.
Published: March 2007

The physicomechanical properties and processes of thermal crosslinking of latex acrylic polymer films containing functional groups of different chemical nature were studied. Improvement of properties characteristic of latex copolymers containing methylolamide groups is explained by orientated location of hydrophilic groups on the surface of latex particles during emulsion copolymerisation, that, in its turn, leads to a more ordered arrangement of macrochains. An optimum content of methylolamide groups as regards crosslinking processes was established and explained by steric location of these groups on the surfaces of latex particles. A similar optimum is not observed for crosslinking by watersoluble resin of latex copolymers containing groups of hydrophobic glycidylmethacrylate.
Luminescence studies of polymer behaviour
Authors: North Alastair M.
Published: March 2007

Luminescence techniques can be used to study polymer systems both as an analytical tool and as a means of studying molecular behaviour. In the latter context, some very interesting information may be obtained on a variety of molecular and energy transport processes. Measurements of luminescence intensity and quenching can be used to observe electronic energy transfer processes (both along polymer chains and from polymer chains to additive molecules). These have a technical importance in that they are the photophysical processes which precede the chemical phenomena important in photodegradation or photostabilisation of polymers. The basic criteria for energy transfer are introduced and examples are given of “down‐chain” energy migration coefficients for a number of polymers. Studies of the depolarisation of luminescence can be used as a measurement of rotation in the electronic excited state of the photoactive group. Fluorescence depolarisation is introduced and examples are given of processes with nanosecond relaxation times. The concept of phosphorescence depolarisation is also mentioned, and the first use of this to study processes with millisecond relaxation times is illustrated.
Self‐association in {2‐[3,4‐alkylenedioxy‐5‐(3‐pyridyl)]‐thienyl}alkanols: an NMR, IR, and single‐crystal X‐ray study
Authors: Lomas John S. , Cordier Christine , Adenier Alain , Maurel François , Vaissermann Jacqueline
Published: March 2007

syn‐2,2,4,4‐Tetramethyl‐3‐{2‐[3,4‐alkylenedioxy‐5‐(3‐pyridyl)]thienyl}pentan‐3‐ols self‐associate both in the solid state and in solution. Single‐crystal X‐ray diffraction study of the 3,4‐ethylenedioxythiophene (EDOT) derivative shows that it exists as a centrosymmetric head‐to‐tail, syn dimer in the solid state. The IR spectra of the solids display only a broad OH absorption around 3300 cm−1, corresponding to a hydrogen‐bonded species. 1H Nuclear Overhauser Effect Spectroscopy (NOESY) NMR experiments in benzene reveal interactions between the tert‐butyl groups and the H2 and H6 protons of the pyridyl group. Two approaches have been used to determine association constants of the EDOT derivative by NMR titration, based on the concentration dependence of (i) the syn/anti ratio and (ii) the OH proton shift of the syn rotamer. Reasonably concordant results are obtained from 298 to 323 K (3.6 and 3.9 M−1, respectively, at 298 K). Similar values are obtained from the syn OH proton shift variation for the 3,4‐methylenedioxythiophene (MDOT) derivative. Concentration‐dependent variation of the anti OH proton shift in the latter suggests that the anti isomer associates in the form of an open, singly hydrogen‐bonded dimer, with a much smaller association constant than the syn rotamer. Self‐association constants for 3‐pyridyl‐EDOT‐alkanols with smaller substituents vary by a factor of 4 from (i‐Pr)2 up to (CD3)2, while the hetero‐association constants for the same compounds with pyridine vary slightly less. Copyright © 2007 John Wiley & Sons, Ltd.
Growth deceleration of children on inhaled corticosteroids is compensated for after the first 12 months of treatment
Authors: Anthracopoulos Michael B. , Papadimitriou Anastasios , Panagiotakos Demosthenes B. , Syridou Garyfalia , Giannakopoulou Eleni , Fretzayas Andrew , Nicolaidou Polyxeni , Priftis Kostas N.
Published: March 2007

Timing and duration of linear growth suppression in children on long‐term inhaled corticosteroids (ICS) are not entirely clear; we undertook a “pragmatic” study to determine growth of asthmatic children on long‐term ICS managed by a flexible dosing step‐down approach. Standard deviation scores of height (HSDS), height velocity (HVSDS), and body mass index (BMISDS) of pre‐pubertal asthmatic children on maintenance therapy with either budesonide (BUD) or fluticasone propionate (FP) were calculated in a prospective open‐label non‐randomized study. Outcomes were recorded at initiation of ICS, 6, 12, 24, and 36 months, as applicable, and 6 months after ICS treatment discontinuation. Three hundred twenty‐two children on BUD and 319 on FP were enrolled after the completion of 6‐month treatment. The median (range) daily dose at initiation was 400 mcg (400–1,200) and 200 mcg (200–500), the final maintenance 200 mcg (200–400) and 100 mcg (100–200), respectively. In the first 6–12 months, a decrease in HSDS of approximately 18% below baseline values was noted (P < 0.01) that was restored to almost baseline average levels by 24 months, and slightly increased to above baseline during the third year. HVSDS showed a linear increase in both treatment arms (P < 0.01). No differences were found between the two treatment arms regarding HSDS, HVSDS, and BMISDS at any time point over the course of the study. In conclusion, growth deceleration of asthmatic children on maintenance ICS is compensated for after the first 12 months of treatment. This effect does not differ between BUD and FP treatment, despite some variation in the pattern of linear growth. Pediatr Pulmonol. 2007; 42:465–470. © 2007 Wiley‐Liss, Inc.
A small chimeric promoter for high prostate‐specific transgene expression from adenoviral vectors
Authors: Kraaij Robert , van der Weel Laura , de Ridder Corrina M.A. , van der Korput Hetty A.G.M. , Zweistra Joke L.M. , van Rijswijk Angélique L.C.T. , Bangma Chris H. , Trapman Jan
Published: March 2007

BACKGROUND

Specificity of transgene expression is important for safety during gene therapeutical applications. For prostate cancer, transcriptional targeting has been applied but was hampered by loss of specificity and low activity. We constructed a small chimeric promoter for high and prostate‐specific transgene expression from adenoviral vectors.

METHODS

A chimeric promoter, composed of the prostate‐specific antigen (PSA) enhancer and the rat probasin promoter, was cloned into an adenoviral vector and its activity was compared to vectors containing conventional prostate‐specific promoters and the constitutive Cytomegalovirus (CMV) promoter in in vitro and in vivo prostate cancer models.

RESULTS

The chimeric PSA‐probasin promoter was the most active prostate‐specific promoter reaching up to 20% of CMV promoter activity while maintaining prostate‐specificity.

CONCLUSIONS

The chimeric PSA‐probasin promoter is a small promoter that can be utilized in viral vectors for high prostate‐specific transgene expression. Prostate 67: 829–839, 2007. © 2007 Wiley‐Liss, Inc.
Mass spectrometric identification of the trypsin cleavage pathway in lysyl‐proline containing oligotuftsin peptides
Authors: Manea Marilena , Mező Gábor , Hudecz Ferenc , Przybylski Michael
Published: March 2007

Trypsin cleaves specifically peptide bonds at the C‐terminal side of lysine and arginine residues, except for ‐Arg‐Pro‐ and ‐Lys‐Pro‐ bonds which are normally resistant to proteolysis. Here we report evidence for a ‐Lys‐Pro‐ tryptic cleavage in modified oligotuftsin derivatives, Ac‐[TKPKG]4‐NH2) (1), using high‐resolution mass spectrometry and HPLC as primary methods for analysis of proteolytic reactions. The proteolytic susceptibility of ‐Lys‐Pro‐ bonds was strongly dependent on flanking residues, and the flexibility of the peptide backbone might be a prerequisite for this unusual cleavage. While ‐Lys‐Gly‐ bonds in 1 were rapidly cleaved, the modification of these Lys residues by the attachment of a ß‐amyloid(4–10) epitope to yield ‐Lys(X)‐Gly derivatives prevented cleavage of this bond, and provided trypsin cleavage of ‐Lys‐Pro‐ bonds, the pathway of this degradation being independent on the type of Lys‐Nε‐side chains (acetyl group, amino acid, peptide). Substitution of the Lys residues by Ala at the P′2 positions decreased the tryptic cleavage, while replacement of the bulky side chain of Thr at the P2 positions strongly increased the cleavage of ‐Lys‐Pro‐ bonds. Circular dichroism (CD) data of the modified oligotuftsin derivatives are in accord with enhanced flexibility of the peptide backbone, as a prerequisite for increased susceptibility to cleavage of ‐Lys‐Pro‐ bonds. These results obtained of oligotuftsin derivatives might have implications for the proteolytic degradation of target peptides that require specific conformational preconditions. Copyright © 2007 European Peptide Society and John Wiley & Sons, Ltd.
Induction of macrophage migration through lactose‐insensitive receptor by elastin‐derived nonapeptides and their analog
Authors: Maeda Iori , Mizoiri Noriaki , Briones Maria Portia P. , Okamoto Kouji
Published: March 2007

Elastin, one of the extracellular matrix components, is present in tissues requiring extensibility and resilience such as the aorta, lungs, ligaments and skin. Degradation of elastin is observed in diseases such as atherosclerosis, emphysema and metastasis. It has been suggested that degraded elastin‐derived peptides interact with a variety of cell types and are involved in development of diseases. Two nonapeptides, Ala‐Gly‐Val‐Pro‐Gly‐Leu‐Gly‐Val‐Gly (AGVPGFGVG) and Ala‐Gly‐Val‐Pro‐Gly‐Phe‐Gly‐Val‐Gly (AGVPGFGVG), exist in hydrophobic regions of elastin. In this paper, we characterized these elastin‐derived nonapeptides by macrophage migration assay. Both nonapeptides induced a maximal migration at 10−8 M and elicited the same degree of responsiveness. To investigate the role of the sixth residue of the nonapeptides, seven analog peptides in which Leu or Phe is substituted by Ile, Val, Ala, Gly, Pro, Lys or Glu were synthesized and their macrophage migration activity tested. Among the nonapeptide analogs, only Ala‐Gly‐Val‐Pro‐Gly‐Ile‐Gly‐Val‐Gly induced the migration of macrophages at the optimal concentration of 10−9 M and its responsiveness was the same as that of parent nonapeptide AGVPGFGVG. Results of the deactivation tests and the effect of lactose on macrophage migration showed that a lactose‐insensitive receptor which mainly recognizes Ala‐Gly‐Val‐Pro‐Gly‐Ile‐Gly‐Val‐Gly is presumably present on the membrane of macrophages in addition to the elastin‐binding protein (EBP) sensitive to lactose. These results suggest that Leu, Phe and Ile residues at the sixth position of elastin‐derived nonapeptides are crucial for inducing macrophage migration and in particular, Ile residue is important for the recognition by receptor insensitive to lactose. Copyright © 2007 European Peptide Society and John Wiley & Sons, Ltd.
The solution structure of horseshoe crab antimicrobial peptide tachystatin B with an inhibitory cystine‐knot motif
Authors: Fujitani Naoki , Kouno Takahide , Nakahara Taku , Takaya Kenji , Osaki Tsukasa , Kawabata Shun‐ichiro , Mizuguchi Mineyuki , Aizawa Tomoyasu , Demura Makoto , Nishimura Shin‐Ichiro , Kawano Keiichi
Published: March 2007

Tachystatin B is an antimicrobial and a chitin‐binding peptide isolated from the Japanese horseshoe crab (Tachypleus tridentatus) consisting of two isopeptides called tachystatin B1 and B2. We have determined their solution structures using NMR experiments and distance geometry calculations. The 20 best converged structures of tachystatin B1 and B2 exhibited root mean square deviations of 0.46 and 0.49 Å, respectively, for the backbone atoms in Cys4‐Arg40. Both structures have identical conformations, and they contain a short antiparallel β‐sheet with an inhibitory cystine‐knot (ICK) motif that is distributed widely in the antagonists for voltage‐gated ion channels, although tachystatin B does not have neurotoxic activity. The structural homology search provided several peptides with structures similar to that of tachystatin B. However, most of them have the advanced functions such as insecticidal activity, suggesting that tachystatin B may be a kind of ancestor of antimicrobial peptide in the molecular evolutionary history. Tachystatin B also displays a significant structural similarity to tachystatin A, which is member of the tachystatin family. The structural comparison of both tachystatins indicated that Tyr14 and Arg17 in the long loop between the first and second strands might be the essential residues for binding to chitin. Copyright © 2007 European Peptide Society and John Wiley & Sons, Ltd.
A novel approach for simultaneous determination of 2‐mercaptobenzimidazole and derivatives of 2‐thiouracil in animal tissue by gas chromatography/mass spectrometry
Authors: Liu Yuan , Zou Qiong‐Hui , Xie Meng‐Xia , Han Jie
Published: March 2007

A novel approach for determination of 2‐mercaptobenzimidazole (MBI) and other thyreostatic residues in animal tissues by gas chromatography/mass spectrometry (GC/MS) in selected ion monitoring mode was developed. The analytes in animal tissues (including hypothyroid, pork muscle and beef samples) were extracted by acetonitrile, and then purified by a matrix solid‐phase dispersion (MSPD) procedure after the extraction residues had been dissolved in water. The thyreostatic residues were derivatized by pentafluorobenzyl bromide (PFBBr) under strong basic conditions and then N‐methyl‐N‐(trimethylsilyl)trifluoroacetamide (MSTFA) before GC/MS analysis. Different kinds of solid supports with various polarities for the MSPD procedure were investigated, and it was found that silica gel was suitable for the purpose. The average recoveries of the thyreostatic drugs in animal tissues ranged from 71.5–96.9% with the relative standard deviations below 10%. By using the developed method, the limits of detection were 10 µg/kg for MBI; 5 µg/kg for 6‐phenyl‐2‐thiouracil; and 2 µg/kg for 2‐thiouracil, 6‐methyl‐2‐thiouracil and 6‐propyl‐2‐thiouracil. The stability of the thyreostatic drugs in spiked animal tissues was tested, and the results showed that the thyreostatic drugs did not decompose within 3 months if the sample was stored in darkness below −20°C. Copyright © 2007 John Wiley & Sons, Ltd.
MSE with mass defect filtering for in vitro and in vivo metabolite identification
Authors: Bateman Kevin P. , Castro‐Perez Jose , Wrona Mark , Shockcor John P. , Yu Kate , Oballa Renata , Nicoll‐Griffith Deborah A.
Published: March 2007

Metabolite identification studies involve the detection and structural characterization of the biotransformation products of drug candidates. These experiments are necessary throughout the drug discovery and development process. The use of high‐resolution chromatography and high‐resolution mass spectrometry together with data processing using mass defect filtering is described for in vitro and in vivo metabolite identification studies. Data collection was done using UPLC™ coupled with an orthogonal hybrid quadrupole time‐of‐flight mass spectrometer. This experimental approach enabled the use of MSE data collection (where E represents collision energy) which has previously been shown to be a powerful approach for metabolite identification studies. Post‐acquisition processing with a prototype mass defect filtering program was used to eliminate endogenous interferences in the study samples, greatly enhancing the discovery of metabolites. The ease of this approach is illustrated by results showing the detection and structural characterization of metabolites in plasma from a preclinical rat pharmacokinetic study. Copyright © 2007 John Wiley & Sons, Ltd.
Immobilized polysaccharide derivatives: chiral packing materials for efficient HPLC resolution
Authors: Ikai Tomoyuki , Yamamoto Chiyo , Kamigaito Masami , Okamoto Yoshio
Published: March 2007

Polysaccharide‐based chiral packing materials (CPMs) for high‐performance liquid chromatography have frequently been used not only to determine the enantiomeric excess of chiral compounds but also to preparatively resolve a wide range of racemates. However, these CPMs can be used with only a limited number of solvents as mobile phases because some organic solvents, such as tetrahydrofuran, chloroform, and so on, dissolve or swell the polysaccharide derivatives coated on a support, e.g., silica gel, and destroy their packed columns. The limitation of mobile phase selection is sometimes a serious problem for the efficient analytical and preparative resolution of enantiomers. This defect can be resolved by the immobilization of the polysaccharide derivatives onto silica gel. Efficient immobilizations have been attained through the radical copolymerization of the polysaccharide derivatives bearing small amounts of polymerizable residues and also through the polycondensation of the polysaccharide derivatives containing a few percent of 3‐(triethoxysilyl)propyl residue. © 2007 The Japan Chemical Journal Forum and Wiley Periodicals, Inc. Chem Rec 7: 91–103; 2007: Published online in Wiley InterScience (www.interscience.wiley.com) DOI 10.1002/tcr.20107
7. Sorting out genital ulceration
Authors: Sonnex Chris
Published: March 2007

Genital herpes is the commonest cause of genital ulceration in the UK, but other, less common causes, such as syphilis or fixed drug eruption, should be excluded. Dr Sonnex provides an overview of genital ulceration relevant to primary care and outlines approaches to management. Copyright © 2007 Wiley Interface Ltd
Determination of solid fat index by fourier transform infrared spectroscopy
Authors: van de Voort F. R. , Memon K. P. , Sedman J. , Ismail A. A.
Published: March 2007

A unique and rapid Fourier transform infrared (FTIR) spectroscopic method for the determination of solid fat index (SFI) of fats and oils was developed, which is capable of predicting the SFI profile of a sample in approximately two minutes, without the need for tempering. Hydrogenated soybean oil samples (n=72), pre‐analyzed for SFI by dilatometry, were melted and their FTIR spectra acquired using a 25 μm NaCl transmission flow cell maintained at 80°C. Approximately half the samples were used for calibration, with the balance used as validation samples. Partial least squares (PLS) calibrations were developed from selected spectral regions that are associated with thecis, trans, ester linkage and fingerprint regions of the spectrum and related to the dilatometric SFI values obtained at 50, 70, 80, and 92°F. The calibrations were initially optimized and cross‐validated by using the “leave one out” approach, with the accuracy and reproducibility of the calibration models assessed by predicting the validation samples. The overall cross validation accuracy of the PLS calibration models was in the order of ±0.71 SFI units over the four temperatures. Week‐to‐week validation accuracy and reproducibility was determined to be ±0.60 and ±0.38 SFI units, respectively, the reproducibility being within the specifications associated with the dilatometric reference method. To facilitate routine “on‐line” FTIR analyses, a Visual Basic program was written to drive the spectrometer, prompt the user to load the sample, calculate, and print the SFI values determined from the PLS calibrations. As structured, the FTIR method has the potential to serve as a viable substitute for the traditional dilatometric SFI method, with the elimination of the tempering step reducing analysis time from hours to minutes. The FTIR approach should also be applicable to the determination of solid fat content if calibrated against solids data obtained by nuclear magnetic resonance.
Cessation of polyunsaturated fatty acid formation in four selected filamentous fungi when grown on plant oils
Authors: Kendrick Andrew , Ratledge Colin
Published: March 2007

Four fungi,Conidiobolus nanodes, Entomophthora exitalis, Mortierella isabellina, andMucor circinelloides, were grown on various oils (triolein, sesame, safflower, linseed, and oil fromM. isabellina) and produced lipids in which the fatty acids were predominantly the same as those of the original staring substrate. Only in the first two cases was there evidence of a small amount of chain elongation and of fatty acid desaturation taking place. The extent of this was only about 10% of that seen in glucose‐grown cells. The apparent repression of the fatty acid desaturases and elongases was not reversed by growing cells on glucose and oils as mixed substrates—the fatty acid profiles were the same as when the fungi had grown in oils alone. Neither was the cessation of polyunsaturated fatty acid synthesis due to the presence of nonoil components (NOC) in the oil. Only the NOC from sesame oil affected one single conversion, that of 20∶3n‐3 to 20∶4n–6. We conclude that fatty acid desaturase and elongase systems are repressed either partially or completely in a filamentous fungi grown on triacylglycerol oils.