bluuebunny/crossref_metadata_2025 huggingface dataset:
Radiosynthesis of 3-{[4-(4-[18F]fluorobenzyl)]piperazin-1-yl}methyl-1H-pyrrolo[2,3-b]pyridine: A potential dopamine D4 receptor imaging agent
Authors: Hai-Bin Tian , Duan-Zhi Yin , Jun-Ling Li , Lan Zhang , Cun-Fu Zhang , Yong-Xian Wang , Wei Zhou
Published: December 2003

The dopamine D4 receptor (D4R) is expressed in low density in various extrastriatal brain regions. This receptor subtype is discussed in relation to the pathophysiology and treatment of schizophrenia but to date no selective positron emission tomography (PET) ligand is available to study its distribution in vivo . The 7-azaindole derivative 3-{[4-(4-iodophenyl)piperazin-1-yl]-methyl}-1H-pyrrolo[2,3-b]pyridine (L-750,667) is a novel, high-affinity (K
i=0.51nM) and selective D4R ligand. L-750,667 analogue 3-{[4-(4-[18F]fluorobenzyl)]piperazin-1-yl}methyl-1H-pyrrolo[2,3-b]-pyridine was prepared by reacting 3-(piperazin-1-yl)-methyl-1H-pyrrolo[2,3-b]pyridine with 4-[18F]fluorobenzaldehyde, which was labeled with no carrier added [18F]fluoride. The radiochemical yield of 3-{[4-(4-[18F]fluorobenzyl)]piperazin-1-yl}methyl-1H-pyrrolo[2,3-b]pyridine was 12.0 at end of synthesis (EOS), and the synthesis time was 73min. The labeled benzaldehydes may be useful precursors for the radiosyntheses of other complex radiotracers for PET.
Biosorption of americium-241 by Candida sp.
Authors: Luo Shunzhong , Liu Ning , Yang Yuanyou , Zhang Taiming , Jin Jiannan , Liao Jiali
Published: December 2003

As an important radioisotope in nuclear industry and other fields, americium-241 is one of the most serious contamination concerns duo to its high toxicity and long half-life. In this experiment, the biosorption of 241Am from solution by Candida sp., and the effects of various experimental conditions on the adsorption were investigated. The preliminary results showed that the adsorption of 241Am by Candida sp. was efficient. 241Am could be removed by Candida sp. of 0.82g/L (dry weight) from 241Am solutions of 5.6-111MBq/L (44.3-877.2μg/L)(C
0), with maximum adsorption rate (R) of 98 and maximum adsorption capacities (W) of 63.5MBq/g biomass (dry weight) (501.8μg/g). The biosorption equilibrium was achieved within 4 hour and the optimum pH was pH=2. No significant differences on 241Am adsorption were observed at 10°C–45°C, or in solutions containing Au3+ or Ag+, even 1500 times or 4500 times above the 241Am concentration, respectively. The relationship between concentrations and adsorption capacities of 241Am indicated the biosorption process should be described by a Langmuir adsorption isotherm.
Determination of uranium(IV) hydrolysis constants and solubility product of UO2·xH2O
Authors: Fujiwara Kenso , Yamana Hajimu , Fujii Toshiyuki , Moriyama Hirotake
Published: December 2003

The hydrolysis constants of tetravalent uranium were determined by a solvent extraction method using thenoyltrifluoroacetone(TTA) and233U. The distribution ratio of U(IV) was measured as a function of the pHcvalue in the aqueous phase atI=0.1, 0.5 and 1.0, and was analyzed to obtain the hydrolysis constants (βm) of U(OH)m(4-m)+at the standard state (I=0). By taking the specific ion interaction theory (SIT) for ionic strength corrections, the hydrolysis constants atI=0 were determined to beβ1°=13.71±0.31,β2°=26.12±0.21 andβ3°=36.85±0.36, together with the ion interaction coefficients of UOH3+, U(OH)22+and U(OH)3+. The solubility product (Ksp) for the reaction of UO2·xH2O=U4++4OH-+ (x-2)H2O was also calculated to be logKsp° =-53.93±0.20 by considering the hydrolysis constants.
Disequilibria in the disintegration series of U and Th and chemical parameters in thermal spring waters from the Tatun volcanic area (Taiwan)
Authors: Lin Chun-Chih , Chu Tieh-Chi , Huang Yu-Fen
Published: December 2003

The activity concentrations of238U,234U,230Th,226Ra,232Th, and228Th in thermal spring waters in the Tatun volcanic area were determined. Parameters including acidity, Cl-and {SO42-concentrations in spring waters at the sampling sites have been investigated to allow interpretation of the migration of the radionuclides, and to elucidate the influence of these parameters on the variations of radionuclide contents. Radioactive disequilibria were found in uranium and thorium series in thermal spring waters. The contents of uranium and thorium decreased with increasing pH. The ratios of230Th/234U,226Ra/230Th and228Th/232Th show significant disequilibria. The226Ra/230Th ratio (0.60–34.8) decreased with the Cl-or {SO42-concentration. All228Th/232Th ratios (1.01–9.49) deviated from unity due to the co-precipitation of228Ra with barium and lead sulfate.
Direct labeling studies of octapeptides with rhenium-188
Authors: Faintuch B. L. , Pereira N. P. S. , Faintuch S. , Muramoto E. , Silva C. P. G.
Published: December 2003

The somatostatin octapeptide lanreotide and octreotide were labeled with rhenium-188 by direct method. The optimization of the labeling, the in vitro stability of the complexes and the biodistribution were evaluated. Labeling efficiency was generally greater than 95. The best time for reaction was 2hours. 188Re-lanreotide gave better radiochemical yields than 188Re-octreotide, and it was stable for a longer time (24 vs. 4 hours), but the mass of lanreotide had to be larger than that for octreotide (350 vs. 250μg), and the required ratio between mass of stannous chloride and peptide was also greater for lanreotide. Use of tartrate/phthalate buffer with 188Re-octreotide gave better radiochemical results and showed more labeling stability than the use of acetate/acetic acid buffer. The results of Cys challenge for 188Re-peptides revealed higher chelation strength for 188Re-octreotide than for 188Re-lanreotide for concentrations of cysteine below 1mM. For a concentration of cysteine of 100mM the rate of transchelation of 188Re to cysteine was the same for both peptides. The CD50 value for 188Re-octreotide was 10mM of cysteine and for 188Re-lanreotide, it was 55mM.188Re-labeled peptides were distributed in the gastrointestinal tract or in the kidneys and rapid blood clearance was observed in the first hour. Results indicated that the products can be obtained with high radiochemical purity, appropriate for in vivo studies to assess their efficacy in radioimmunotherapy.
Speciation of uranium(VI) at the solid/solution interface: sorption modeling on zirconium silicate and zirconium oxide
Authors: Lomenech C. , Drot R. , Simoni E.
Published: December 2003

In the field of nuclear waste storage, knowledge of the sorption behavior of radionuclides onto mineral surfaces is of fundamental importance in order to evaluate environmental impacts. We have studied uranyl ion sorption mechanisms onto zirconium silicate and zirconium oxide with a double approach, coupling both macroscopic and structural investigations. The spectroscopic results, reported in a previous paper, allowed a complete determination of the different species involved in the studied sorption reactions. This paper presents the results of the macroscopic part of the study. Surface characterizations of the solids were first carried out: determination of the pH of the point of zero charge, of the surface site densities and of the surface acidity constants. The experimental retention data were then interpreted in terms of a constant capacitance model using the FITEQL code. Results from structural investigation were used to constrain the modeling. This coupled approach led to accurate reactions stoichiometry and associated sorption constants values, since they were determined with respect to different experimental results, both macroscopic and microscopic.
On the study of Th(IV)-humic acid interactions by competition sorption studies with silica and determination of global interaction constants
Authors: Reiller Pascal , Moulin Valérie , Casanova Florence , Dautel Christian
Published: December 2003

The influence of humic acids (HA) on the retention of thorium (IV) onto the surface of silica colloids is investigated. Thorium is considered as an analogue of tetravalent actinides (U, Np, Pu), except for the fact that it has no f electrons. Silica (SiO2) is chosen as a model surface because it is a component of many minerals and because of its weak HA sorption properties. Retention experiments are performed by batch procedure at constant ionic strength (I = 0.1M NaClO4), at various pH (2 to 9) and HA concentrations (1–100mg/L). The sorption of Th(IV) onto colloidal amorphous silica is characterised using a surface complexation model. The ternary system (i.e. HA-Th-Silica) clearly shows the influence of HA on Th(IV) retention. This can lead to a strong reduction of the amount of Th(IV) sorbed onto silica in the presence of HA compared to silica colloids without HA, due to a predominant part of thorium present in solution as humic complexes. In a pH range where no organic coating onto silica occurs, there is a competitive reaction between Th(IV) sorption onto the silica surface and onto HA reactive functional groups. In this case, Schubert´s method is applied to obtain a global interaction constant for the Th(IV)-HA system. The large interaction constant values indicate a strong affinity of HA for Th(IV).
Structural characterization of a ternary Fe(III)-U(VI)-citrate complex
Authors: Dodge Cleveland J. , Francis Arokiasamy J.
Published: December 2003

Citric acid, a naturally occurring hydroxycarboxylic acid, forms bidentate, tridentate, dinuclear, or polymeric species, depending on the metal. In the presence of iron and uranium a ternary Fe: U: citric acid complex is formed. We determined the molecular structure of the ternary complex in both the aqueous and solid phase. Fourier transform infrared spectroscopy (FTIR) showed the presence of uni- and bi-dentate bonding of the citric acid to the metals, and the involvement of the α-hydroxyl group. Analysis of molecular fragments generated from time-of-flight secondary ion mass spectroscopy (TOF-SIMS) confirmed the bonding of terminal carboxylate groups of citric acid to uranium and iron. Extended X-ray absorption fine structure (EXAFS) analysis revealed the dinuclear nature of the Fe bonding to citrate and mononuclear uranium species with citrate. Coordination of a sodium atom to the iron was also noted. The proposed empirical formula for the complex is [NaFe2(μ-O)(μ-citrato)(OH)2(H2O)(C6H4O7)bis(UO2)(C6H5O7)]7-. The structure consists of a dinuclear ferric ion core coordinated through an oxy (μ-O) and a carboxylate (μ-citrato) group of citric acid. The mononuclear uranyl ions are coordinated in bidentate fashion to the central carboxylate groups of citric acid and tridentate coordinated to citric acid.
Ortsaufgelöste Laser-Doppler-Geschwindigkeitsprofilmessung von Grenzschichtströmungen (Spatial-resolved Laser Doppler Velocity Profile Measurement of Boundary Layer Flows)
Authors: Czarske J. , Büttner L. , Razik T. , Müller H.
Published: December 2003

Die Erfassung von Scherströmungen erfordert Geschwindigkeitsmessverfahren mit hoher Ortsauflösung. Laser-Doppler-Sensoren eignen sich dafür aufgrund des präzisen, berührungslosen Messprinzips. Die Ortsauflösung ist aber in der Regel durch die Größe des Messvolumens auf typisch 50 μm begrenzt. In diesem Aufsatz wird auf ein neuartiges Messprinzip eingegangen, das eine ortsaufgelöste Geschwindigkeitsmessung innerhalb des Messvolumens ermöglicht. Die Ortsauflösung ist nur durch die Signalqualität begrenzt. Erreicht wurde eine Ortsauflösung von ca. 1,6 μm. Steile Scherschichten können erfasst werden. Die Anwendungen des Laser-Doppler-Geschwindigkeitsprofilsensors liegen z.B. in der Messung von Grenzschichtströmungen sowie von Rohrströmungen.
Optische Verarbeitung von interferometrischen Streifenbildern und die Fehlererkennung durch Wavelet-Filterung (Optical Processing of Interferometric Fringes and Detection of Faults by Wavelet Filtering)
Authors: Kallmeyer F. , Wernicke G. , Krüger S. , Gruber H. , Osten W. , Kayser D.
Published: December 2003

Das Erkennen und Klassifizieren von Fehlern ist eine wichtige Aufgabe der optischen zerstörungsfreien Materialprüfung in der industriellen Qualitätskontrolle. Eine Vielzahl von Daten über Fehler im Material sind in interferometrischen Streifenmustern enthalten. Diese Daten müssen für die weitere Auswertung reduziert werden. Eine Möglichkeit der Datenreduktion ist durch die Wavelet-Transformation gegeben. Fehler in interferometrischen Streifenmustern sollen durch Wavelet-Filter erkannt, lokalisiert und klassifiziert werden. Wavelet-Funktionen sind sowohl im Ortsraum als auch im Frequenzraum lokalisiert und eignen sich deshalb zur Extraktion von Merkmalen ohne Verlust der räumlichen Zuordnung. Eine Klassifizierung der Interferogramme ist möglich, da die Fehlerklassen charakteristische Eigenschaften haben, die mit bestimmten Klassen von Wavelet-Filtern erkannt werden können.
Laser-Speckle-Dehnungsmessung und deren Anwendung in der Materialwissenschaft (Laser Speckle Strain Measurement and its Application in Material Science)
Authors: Thurner T. , Schneider S. C. , Zagar B. G.
Published: December 2003

In diesem Artikel werden Prinzip, Aufbau und Einsatzmöglichkeiten sowie ausgewählte Messergebnisse für zwei auf Laser-Speckle-Verfahren beruhende Sensorsysteme erläutert und gegenübergestellt. Der grundsätzliche Unterschied zwischen den Systemen besteht in der optischen Anordnung. Im ersten System werden zwei kleine, mit Laserlicht beleuchtete Oberflächenbereiche maßstabsgetreu auf eine Kamera mit genau definierter Geometrie (CCD) abgebildet und deren belastungsbedingte Verschiebung mit hoher Auflösung ermittelt. Der Laser übernimmt dabei die Funktion der Erzeugung eines kontrastreichen Musters, welches charakteristisch für die betrachteten Oberflächenbereiche der Probe ist (Fingerabdruck der Oberfläche). Die Differenz der beiden Verschiebungswerte, bezogen auf die durch den Abstand der beobachteten Bereiche definierte Basislänge, ergibt die gesuchte Dehnung der Probe. Da die Auflösung des Systems mit zunehmender Basislänge besser wird und das Messprinzip aber über eben diese Basislänge mittelt und viele Anwender einen Sensor benötigen, der die Messgröße ortsmäßig auflösen kann, wurde ein in dieser Hinsicht verbessertes Verfahren basierend auf einer Idee von Yamaguchi entwickelt. In diesem Artikel werden Eigenschaften und Anwendungsmöglichkeiten beider Systeme gegenübergestellt und diskutiert.
Vergleichbarkeit von Verfahren zur Messung der elektromagnetischen Störfeldstärke (Comparability of Disturbance Field Strength Measurement Methods)
Authors: Kappel U.
Published: December 2003

Zur Bewertung der elektromagnetischen Störaussendung elektrischer Geräte werden neben dem derzeit in den einschlägigen Normen vorgesehenen Freifeldmessverfahren in näherer Zukunft weitere Messmethoden den Weg in die Normung finden. Da in letzter Konsequenz alle Messverfahren der Überprüfung des im EMV-Gesetz definierten Schutzziels der Begrenzung der Aussendung dienen müssen, ist es notwendig, ein Verfahren zur Bewertung der Messmethoden hinsichtlich dieser Aufgabenstellung zu entwickeln. In diesem Beitrag werden zwei solcher Verfahren vorgestellt, verglichen und letztlich die Entscheidung für eines der Verfahren gefällt. Besondere Berücksichtigung findet dabei die Modellierung der Prüflinge, da ihre Abstrahlcharakteristik die Ergebnisse der Messungen massiv beeinflusst.
EMV-Ringvergleich der DATech/RegTP/PTB – Ergebnisse, Erkenntnisse und Schlussfolgerungen (EMC-Intercomparison by DATech/RegTP/PTB – Results, Findings and Conclusions)
Authors: Spitzer M. , Münter K. , Pape R. , Glimm J. , Dallwitz L.
Published: December 2003

Mit dem von der DATech in den Jahren 2000/2001 durchgeführten Ringvergleich aller ca. 100 in Deutschland akkreditierten EMV-Laboratorien wurden für Emissionsmessungen, Störspannungsmessungen auf Leitungen sowie für Messungen der Störfestigkeit gegenüber elektromagnetischen Feldern routinemäßige Ergebnisse für ein neutrales Probegerät erzeugt. Aufgrund deren relativer Abweichungen wird eine Einschätzung der EMV-Mess- und -prüfqualität in Deutschland ermöglicht mit dem Ziel, die Resultate aller Laboratorien einander anzugleichen.
Deflektometrie zur Qualitätsprüfung spiegelnd reflektierender Oberflächen (Deflectometry for Quality Control of Specular Surfaces)
Authors: Kammel Sören
Published: December 2003

Defekte auf glänzend lackierten Oberflächen wie z.B. Karosserieteilensind für den menschlichen Betrachter leichter wahrzunehmen — und damit störender — als auf diffus reflektierenden Oberflächen. Aus diesem Grund werden für Werkstücke, deren visuelle Erscheinung relevant für ihre Verwendung ist, besonders empfindliche Messverfahren benötigt. Deflektometrische Messverfahren ahmen die menschliche Wahrnehmung nach, indem sie das zu vermessende Objekt als Spiegel einsetzen, dessen Abbildungseigenschaften die Bestimmung der gewünschten Oberflächenfunktion erlauben. Sie erreichen eine wesentlich höhere Empfindlichkeit als Triangulationsverfahren.
Schnell-Heizapparatur für die strahlenchemische Modifizierung von Polymerfolien im Schmelzezustand (A High Speed Heater for a Radiation-induced Chemical Modification of Melted Polymer Foils)
Authors: Jenschke Wolfgang , Dorschner Helmut , Arnold Dietrich , Stephan Michael , Brünig Harald
Published: December 2003

In der vorliegenden Arbeit wird eine Heizapparatur vorgestellt, mit der dünne Polymerfolien in sehr kurzer Zeit aufgeschmolzen und während einer anschließenden Elektronenbestrahlung auf vorbestimmter Temperatur gehalten werden können. Hierzu wird die Konstruktion der Apparatur sowie die zugehörige Gerätetechnik vorgestellt, das Regelverhalten diskutiert und einige Testergebnisse von Aufschmelzvorgängen gezeigt. Ein weiterer Schwerpunkt sind Untersuchungen zum Einfluss der Bestrahlungsparameter auf das Regelverhalten der Apparatur während der Elektronenbestrahlung.
Resonance characteristics of whispering gallery modes in parallel‐plates‐type cylindrical dielectric resonators
Authors: Akay M. Fatih , Prokopenko Yuriy , Kharkovsky Sergey
Published: December 2003

In this paper, the results of analytical and numerical investigation of whispering gallery modes (WGMs) in parallel‐plates‐type cylindrical anisotropic and isotropic dielectric resonators are presented. The dependence of the WGMs' resonant frequency, Q‐factor, and energy‐filling factor upon resonator parameters for the wide range of the azimuthal index has been studied numerically. The optimization of resonator parameters for sensing applications is discussed. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 40: 96–101, 2004; Published online in Wiley Interscience (www.interscience.wiley.com). DOI 10.1002/mop.11296
A 2‐pole CPW resonator BPF with attenuation poles using point‐coupled λ/4 resonators
Authors: Wada Kouji , Tatsumi Makoto , Kamiyama Tomohide , Hashimoto Osamu , Harada Hiroshi
Published: December 2003

The aim of this study is to examine a coplanar bandpass filter (BPF) with attenuation poles using point‐coupled λ/4 resonators. The first part of this paper describes the resonance characteristics of the λ/4 resonators with chosen excitation methods. Secondly, the design of the BPF with attenuation poles using the λ/4 resonators is carried out based on general filter theory with narrowband approximation. A comparison between theory and experiment is also performed. It is confirmed that the method presented is useful for improving the BPF's skirt characteristics using λ/4 resonators. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 40: 101–107, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11297
Efficient and low‐noise gain‐flattened double‐pass L‐band erbium‐doped fiber amplifier
Authors: Harun S. W. , Ahmad H.
Published: December 2003

A new double‐pass long‐wavelength‐band erbium‐doped fiber amplifier with enhanced noise figure characteristics is demonstrated by adding a short length of forward pumped erbium‐doped fiber (EDF) in front of the double‐pass amplifier. By adding 7 m of EDF, the amplifier achieves a flat‐gain output at about 34.2 dB with a gain variation of less than 1.3 dB at the wavelength region 1568–1598 nm. The corresponding noise figures vary from 5.0 to 5.7 dB, which is improved by 1.7 to 7.5 dB over the flat‐gain region, as compared to that of the conventional double‐pass amplifier. This new amplifier with high gain and low noise figure can be useful as an inline amplifier in a wavelength division multiplexing transmission system. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 40: 112–114, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11300
Low‐frequency fast inhomogeneous plane‐wave algorithm (LF‐FIPWA)
Authors: Jiang L.J. , Chew W.C.
Published: December 2003

A new method, the low‐frequency fast inhomogeneous plane‐wave algorithm (LF‐FIPWA) is presented to extend the traditional multilevel fast multipole algorithm (MLFMA) and fast inhomogeneous plane‐wave algorithm (FIPWA) seamlessly into the low‐frequency range. It uses evanescent‐wave extrapolation and translation techniques to overcome the low‐frequency breakdown problem. The accuracy can be well controlled over a broad frequency range. Numerical examples show the effectiveness of this new algorithm. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 40: 117–122, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11302
Modeling of optical link for OCDMA‐based cascaded optical networks
Authors: Reddy Y. Bhanuprakash , Alphones Arokiaswami
Published: December 2003

In cascaded optical networks, the BER performance of optical CDMA (OCDMA) signals has been evaluated. In order to simulate the optical link, the optical source, receiver, and fiber channel are modeled as lowpass filters by using Butterworth/Chebyshev approximations. Bipolar codes are used for spreading, and at the chip rate of 8 Gc/s, multi‐user interference (MUI) and distortion introduced by the optical link are found to be insignificant. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 40: 122–124, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11303
A novel method to optimize optical‐fiber Raman amplifiers using equally spaced low‐power laser diode pumps
Authors: Zhou Junhe , Chen Jianping , Li Xinwan
Published: December 2003

This paper proposes a novel, less expensive optical‐fiber Raman amplifier, which employs equally spaced low‐power laser diodes as pumps. The genetic algorithm (GA) is modified to optimize the configuration of the pumps. Simulation results show that, for operation in the bandwidth from 1530 to 1610 nm, the amplifier provides a gain profile of small in‐band ripple and sharp out‐of‐band roll off. About 20% of pump power can be saved. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 40: 124–127, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11304
Design and experimental results of bilateral interdigital coplanar delay line for MMICs
Authors: Yoon Hargsoon , Abraham Jose K. , Varadan Vijay K.
Published: December 2003

The design and development of a bilateral interdigital coplanar waveguide (Bi‐CPW) delay line that can be used as a passive device in MMICs is presented in this paper. This Bi‐CPW design is analyzed using the conformal mapping method and realized via an RF‐CMOS‐compatible fabrication process using high‐k dielectric thin film. The Bi‐CPW design shows 180° phase delay at 10 GHz for a 2.8‐mm transmission line. It is shown that a conventional coupler can be implemented in a few mm2 area without any lumped element. The measured results show the potential for monolithic integration of conventional couplers using Bi‐CPW phase delay line. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 40: 127–130, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11305
Patch‐antenna efficiency based on Wheeler cap and measured Q factor
Authors: García‐García Quiterio
Published: December 2003

A new method to determine antenna efficiency, based on the Wheeler cap technique, is presented. It uses the ratio between measured Q factors of the shielded and free‐space antenna impedances as a measure of radiation efficiency. The measured reflection coefficient of the antenna is fitted to an analytical function from which the unloaded Q can be determined. The method is particularized to microstrip patch antennas and is illustrated with simulated and measured results. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 40: 132–142, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11307
Compact spurious free CPW bandpass filters based on electromagnetic bandgap structures
Authors: Martin F. , Bonache J. , Gil I. , Falcone F. , Lopetegi T. , Laso M. A. G. , Sorolla M.
Published: December 2003

In this paper, coplanar waveguide (CPW) bandpass filters based on capacitively coupled resonators and periodic perturbation in slot width are proposed. Due to periodicity, the structure behaves as a reflector in a certain frequency band and harmonic suppression is achieved. Slot‐width modulation has been implemented through the approximation of the ground planes to the conductor strip at periodic locations. The equivalent capacitance of the line is thus enhanced, with the result of a significant slow‐wave effect. In comparison to a conventional design, the fabricated prototype is 1.4 times smaller and exhibits significant rejection of frequency parasitics. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 40: 146–148, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11309
An asymmetrical feed arrangement for improved impedance bandwidth of planar monopole antennas
Authors: Ammann M. J. , Chen Zhi Ning
Published: December 2003

The use of an asymmetrical feed probe is shown to significantly increase the impedance bandwidth of a square planar monopole antenna. The feed probe is offset from the center of the planar element. The optimum location of the feed probe is shown to increase the impedance bandwidth by a factor of 3.4. The effect of the asymmetry on radiation patterns is also shown. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 40: 156–158, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11313
Characteristics of a compact microstrip antenna
Authors: Gupta Vibha R. , Gupta Nisha
Published: December 2003

The characteristics of a bow‐shaped microstrip patch antenna are analyzed and compared with a conventional rectangular microstrip antenna. The various parameters such as return loss, gain, and VSWR are determined and compared. It is found that the center frequency of the bow‐shaped antenna is lower by about 12.82% than that of the conventional rectangular microstrip antenna. This implies that the size of the patch needs to be reduced in order to maintain the same resonant frequency. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 40: 158–160, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11314
Conjugation symmetry in linear electromagnetism in extension of materials with negative real permittivity and permeability scalars
Authors: Lakhtakia Akhlesh
Published: December 2003

If all space is occupied by a linear bianisotropic material—whether homogeneous or not—then the concurrent replacements of the permittivity and the impermeability tensors by the negatives of their respective complex conjugates and of the magneto‐electric tensors by their respective complex conjugates (in the Boys–Post representation) imply the conjugation of both E and H, in the absence of externally impressed sources. This conjugation symmetry in linear electromagnetism has observable consequences when the linear bianisotropic material occupies a bounded region. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 40: 160–161, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11315
Six‐port reflectometer based on four 0°/180° microstrip ring couplers
Authors: Mohra Ashraf S.
Published: December 2003

A six‐port reflectometer constructed from a 0°/180° microstrip‐ring coupler is presented. Three different constructions are given with their optimum positions of the q‐point. One of these constructions is realized on an RT/Duroid 5880 at 3 GHz. Good agreement with the measurements obtained using a vector network analyzer is found. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 40: 167–170, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11318
A compact integrated band‐pass filter on a low‐dielectric constant polyimide dry film
Authors: Lim Ohk‐Kun , Lee Joon‐Ik , Kim Yong‐Jun , Park Jae‐Yeong
Published: December 2003

A new compact integrated tapped‐line combline filter, with metal‐insulator‐metal (MIM)‐type capacitive loads, is designed and fabricated using newly proposed micromachining techniques that employ a polyimide dry film as a dielectric layer. For increased uniformity of thickness, a dry‐film fabrication process is developed. The presented filter is realized with a relatively small size, 3.68 by 4.53 mm, on a polyimide dry film and shows up to 50% size reduction as compared with a general quarter‐wavelength filter. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 40: 177–179, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11321
Chorioangioma and its severe infantile sequelae: case report
Authors: Maymon Ron , Hermann Gratiana , Reish Orit , Herman Arie , Strauss Simon , Sherman Dan , Heyman Eli
Published: December 2003

Objective

This case report describes a rare clinical presentation of chorioangioma diagnosed prenatally because of raised‐maternal serum (MS) alpha‐fetoprotein.

Methods

A thirty‐year‐old woman gravida 2, para 1 was referred to the ultrasound unit at 18 weeks of gestation because of abnormal MS triple‐test results. This included AFP level of 14.9 MoM; hCG of 3.42 MoM and uE3 of 1.01 MoM. A detailed anomaly scan revealed a singleton fetus with no sonographically detectable malformations and normal amniotic fluid.

The placenta was posterior. A well‐circumscribed, rounded, predominantly hypoechoic lesion near the chorionic surface measuring 5 × 5 cm and protruding into the amniotic cavity was detected. Color Doppler sonogram showed no blood flow within the mass, but clear fetal waveforms in its periphery were demonstrated, and the diagnosis of chorioangioma was made. The pregnancy was followed uneventfully until 35 weeks of gestation when polyhydramnios and severe fetal cardiomegaly developed. Labor was therefore induced.

Results

A euploid female, who had multiple diffuse cutaneous and liver angiomatosis was born. She died at the age of one month because of cardiac failure and infection.

Conclusions

The present case alerts to the interrelationship between placental and fetal angiomas. This may lead to severe infantile sequelae because of similar lesions. Copyright © 2003 John Wiley & Sons, Ltd.
Congenital cystic adenomatoid malformation: accuracy of prenatal diagnosis, prevalence and outcome in a general population
Authors: Gornall A. S. , Budd J. L. S. , Draper E. S. , Konje J. C. , Kurinczuk J. J.
Published: December 2003

Objectives

Most available data regarding accuracy of prenatal diagnosis, prevalence and outcome of congenital cystic adenomatoid malformation (CCAM) are derived largely from tertiary referral centres and may not reflect general population rates. We aimed to describe the accuracy of prenatal diagnosis, ascertain the population prevalence and post‐natal outcome for cases of suspected CCAM.

Methods

Retrospective collection of prenatal and paediatric data for cases of suspected CCAM notified to the Trent Congenital Anomalies Register 1997 to 2001.

Results

Thirty‐seven cases of CCAM were suspected prenatally. Twenty‐one cases were confirmed post‐natally as having a CCAM (positive predictive value 57%). Eighteen of the 21 cases were delivered at term as live births, 15 of which have undergone successful surgery to date. Thirteen of the 37 cases had apparently resolved by delivery. Three further cases were subsequently found to be cases of lung sequestration or lobar emphysema. Five cases of CCAM were detected after delivery (sensitivity of prenatal detection 81%). The population prevalence at delivery was 9.0 per 1 00 000 total births. Five confirmed cases of CCAM developed hydrops, three required in utero intervention and delivered as live births at term, one was terminated and one died in utero. The overall mortality in the confirmed cases of CCAM was 23% of which the majority were terminations of pregnancy.

Conclusions

Problems of diagnostic accuracy and apparent resolution of CCAM render counselling difficult, although our data suggest that the prognosis is better than others have reported. Confirmation of the diagnosis in the neonatal period is vital in order to obtain the true population prevalence figures and to interpret outcome data. Copyright © 2003 John Wiley & Sons, Ltd.
Living with achondroplasia: attitudes toward population screening and correlation with quality of life
Authors: Gollust Sarah E. , Thompson Richard E. , Gooding Holly C. , Biesecker Barbara B.
Published: December 2003

Objectives

Since the discovery of the gene that causes achondroplasia, population‐wide prenatal screening for this condition has become a possibility. This study sought to assess attitudes toward screening for achondroplasia and correlation with quality of life in a population of individuals affected with achondroplasia and first‐degree relatives.

Methods

Surveys were collected from 189 individuals affected with achondroplasia and 136 average‐statured first‐degree relatives.

Results

While 87% of all respondents would support the use of prenatal screening by affected parents at risk of having a fetus with the homozygous, lethal form of achondroplasia, 29% would support general population prenatal screening for achondroplasia. Attitudes supporting general population screening were more likely to be held by those people with less education, who were affected with achondroplasia, who supported abortion, and who believed that achondroplasia is a serious condition without any accompanying advantages (p < 0.01). Those respondents who felt positively toward offering the prenatal test for individuals at risk for homozygous achondroplasia were more likely to have lower mean quality of life scores and to support abortion in general (p < 0.05).

Conclusion

These data suggest that opinions about prenatal screening are heterogeneous within this study population and are related to individuals' experiences and perceptions of the condition. Future research is needed to assess attitudes toward population screening and quality of life in communities of individuals affected with genetic conditions, both to support policy decisions and to inform the education and counseling provided in the prenatal setting. Copyright © 2003 John Wiley & Sons, Ltd.
Psychotropic drugs and fatal pulmonary embolism
Authors: Parkin Lianne , Skegg David C. G. , Herbison G. Peter , Paul Charlotte
Published: December 2003

Purpose

To examine the association between the use of psychotropic drugs and fatal pulmonary embolism.

Methods

We conducted a national case‐control study of fatal pulmonary embolism. Cases were 75 New Zealand men and women aged 15–59 years who died between 1 January 1990 and 31 December 1998, where the underlying cause of death was certified as codes 415.1, 451 or 453 of the International Classification of Diseases (9th Revision). Four controls, matched for sex and age, were selected from the general practice to which each case had belonged. Information was abstracted from the records of general practitioners, family planning clinics and psychiatric services. Odds ratios and 95% confidence intervals (95% CI) were estimated using conditional logistic regression. The key analyses were restricted to cases (n = 62) and controls (n = 243) without major risk factors for venous thromboembolism.

Results

Compared to non‐use, the adjusted odds ratio for current use of antipsychotic drugs was 13.3 (95% CI: 2.3–76.3). Low potency antipsychotics appeared to carry the highest risk (odds ratio: 20.8 [95% CI: 1.7–259.0]). The main drug involved was thioridazine. The odds ratio for current use of antidepressants was also increased, at 4.9 (95% CI: 1.1–22.5).

Conclusions

Our results for conventional antipsychotics are consistent with previous studies of non‐fatal venous thromboembolism. The finding for antidepressants needs to be replicated in other studies. Copyright © 2003 John Wiley & Sons, Ltd.
Risk assessment of drugs, biologics and therapeutic devices: present and future issues
Authors: Strom B. L.
Published: December 2003

Purpose

The current US system for detecting adverse effects of therapeutics (drugs, devices and biological products) is suboptimal. This report presents the results of an expert workshop on assessing therapeutic risks. This is the second of five workshops coordinated by the Centers for Education and Research on Therapeutics (CERTs) to address the management of therapeutic risks relative to potential benefits.

Methods

The workshop included academic, industry, government and constituency‐based leaders. The focus was on the postapproval phase and procedures in the US, but relevant international issues and attendees were included.

Results

Substantial deficiencies in the current US system for risk assessment were delineated. Improving the system will involve research into methods to improve risk assessment, enhancement and consolidation of data‐handling systems, education of healthcare workers, allocation of financial resources and building of constituencies.

Conclusions

We need leadership on multiple levels for global coordination of risk assessment. We can then begin to fill gaps and produce benefits for industry, health authorities, government agencies, healthcare providers, and most important, the public. Copyright © 2003 John Wiley & Sons, Ltd.
A population‐based study of drug use in the very old living in a rural district of Sweden, with focus on cardiovascular drug consumption: comparison with an urban cohort
Authors: Klarin Inga , Fastbom Johan , Wimo Anders
Published: December 2003

Purpose

To describe drug use among the elderly, with focus on cardiovascular drugs and regional differences.

Methods

Cross‐sectional data from a Swedish population‐based study on ageing and dementia were used. In rural Nordanstig, drug‐use data for 918 participants, 75 years and older (N1), were collected during the period 1995–1998. The data for 335 participants, 84 years and older (N84+), were compared with 418 subjects of the same age group in urban Kungsholmen (K5), data collected 1997–1998.

Results

Over 90% of the participants were using drugs regularly or ‘as needed’. The most common were cardiovascular drugs, nervous system drugs and drugs for the alimentary tract and metabolism. Polypharmacy (five drugs or more) was common, especially among the oldest, 46% (N84+) and 50% (K5). ACE‐inhibitors were used by only 24% of the N1 participants with heart failure. Significantly fewer of cognitively impaired participants were treated with ACE‐inhibitors (OR: 0.44) and beta‐blockers (OR: 0.50). Significant regional differences among the oldest old were found, with more cardiovascular (OR: 2.72) and less antithrombotic drugs (OR: 0.43) in the rural 84+ group.

Conclusions

The extensive drug consumption, high prevalence of polypharmacy and regional differences stress the need for rigorous monitoring of drug use in the elderly. The data also indicate undertreatment of some cardiovascular diseases in the elderly with cognitive impairment. Copyright © 2003 John Wiley & Sons, Ltd.
Local ionization energy and local polarizability
Authors: Jin Ping , Murray Jane S. , Politzer Peter
Published: December 2003

We investigate relationships between molecular polarizability α, volume V, ionization energy I, and average local ionization energy I(). The last of these is a measure of the energy required to remove an electron from any point in the space of an atom or molecule. Molecular polarizability shows a good direct correlation with volume, which can be improved to a minor extent by including an inverse dependence on I and more so by using I() averaged over the surface of the molecule, IS,ave. The pattern of I() on a molecular surface, IS(), exhibits significant variability, and it is shown through a series of examples that this can be related to the electronic structure of the molecule and to local polarizability. Thus, IS() will provide a means of assessing the transferability of regional (e.g., group/bond) polarizabilities from one molecule to another. © 2003 Wiley Periodicals, Inc. Int J Quantum Chem, 2004
CATIVIC: Parametric quantum chemistry package for catalytic reactions: I
Authors: Ruette F. , Sánchez M. , Martorell G. , González C. , Añez R. , Sierraalta A. , Rincón L. , Mendoza C.
Published: December 2003

A quantum chemistry package for catalytic reactions, referred to as CATIVIC and based on simulation techniques of parametric Hamiltonians, is presented. We describe in detail the computational procedures for modeling adsorption on a catalytic substrate, especially the parameterization scheme using examples of atomic Al and AlX bonds (X = H, N, O, Si, Fe) for atomic and molecular parameters. The code features are illustrated with the adsorption of NO on models of ZSM‐5 zeolite doped with Fe. © 2003 Wiley Periodicals, Inc. Int J Quantum Chem, 2004
Ab initio study of dissolution reactions of five‐membered aluminosilicate framework rings
Authors: Xu Hua , Van Deventer J. S. J. , Roszak Szczepan , Leszczynski Jerzy
Published: December 2003

A theoretical study of five‐membered aluminosilicate framework rings and their dissolution products is presented as an approach to model the first step of stilbite geopolymerization in alkaline conditions. The molecular structures, charge distribution, thermodynamic properties, and vibrational spectra were studied for reactants and products of the dissolution process. The properties determined theoretically simulate satisfactorily the available experimental data, indicating that the chosen model of complexes is realistic. These results suggest that the short directional forces operating in minerals are important. The properties calculated for the restricted cluster are a reasonable first‐order representation of those found in the solid state. © 2003 Wiley Periodicals, Inc. Int J Quantum Chem, 2004
Extending the ONIOM integrated MO/MO approach to hydrogen bonding in biologic systems: Serine–water and threonine–water dimers
Authors: Hopkins Brian W. , Tschumper Gregory S.
Published: December 2003

A series of two‐layer ONIOM (MO:MO) methods have been systematically applied to two biologically important hydrogen‐bonded dimers. Single conformations of the serine–water dimer and of the threonine–water dimer were optimized with the MP2 technique and a DZP++ basis set. The counterpoise corrected and uncorrected dissociation energies of the dimers were then computed with RHF, B3LYP, MP2, and CCSD(T) electronic structure techniques with 3‐21G, 6‐31+G(d), and DZP++ basis sets as well as every possible two‐layer ONIOM permutation using either CCSD(T)/DZP++ or MP2/DZP++ as the high‐level method. To judge the performance of each technique, the data are compared to results obtained with the CCSD(T) method and a double‐zeta basis set with diffuse and polarization functions on all atoms [the largest basis set for which CCSD(T) computations were feasible]. MP2 theory reproduces the target CCSD(T) data extremely well. ONIOM schemes that employ model systems including the side‐chain and α‐carbon perform well, introducing errors of less than 0.21 kcal/mol. We observe that MP2:RHF approaches that use this large model system require almost the same CPU time as a B3LYP computation on the entire system but are far more accurate. Guidelines are presented for the application of two‐layer ONIOM methods to hydrogen bonding between similar functional groups in larger biologic systems. © 2003 Wiley Periodicals, Inc. Int J Quantum Chem, 2004
Intrinsic band gap shift in Ti silicalites modified by V ion implantation: Ab initio and density functional theory study
Authors: Zhanpeisov Nurbosyn U. , Kanazawa Yukiya , Yamashita Hiromi , Anpo Masakazu
Published: December 2003

Ab initio and density functional theory quantum chemical calculations show that both the tetrahedrally coordinated V ions and highly dispersed titanium oxide species in the V ion‐implanted Ti silicalites have the tendency to locate in next‐neighboring positions via the formation of a Ti–O–V linkage. The latter was found to play an important role in modifying the electronic nature of the Ti silicalite photocatalysts to enable the absorption band to shift to longer wavelength regions. © 2003 Wiley Periodicals, Inc. Int J Quantum Chem, 2004
Conformational conversion of the boat and chair structures of bicyclo[3.2.0]hept‐6‐ene
Authors: Qin Changyong , Davis Steven R.
Published: December 2003

The conversion between the chair and boat forms of bicyclo[3.2.0]hept‐6‐ene have been studied using ab initio calculations at the Hartree–Fock and MP2 levels using the 6‐31G(d,p) basis set with relative energies determined at the CCSD(T)/MP2 level. The transition state has been located and the activation barrier calculated to be 6.6 kcal/mol; and, the relative energies for the two conformers are close, with the boat form being 4 kcal/mol more stable. Transition‐state theory was used to evaluate the equilibrium thermodynamics. © 2003 Wiley Periodicals, Inc. Int J Quantum Chem, 2004
Computational study of the conformational interconversion of 5,5‐dimethyl‐1,2,3‐trithiacyclohexane (5,5‐dimethyl‐1,2,3‐trithiane)
Authors: Freeman Fillmore , Cha Chansa
Published: December 2003

Ab initio molecular orbital theory and density functional theory (DFT) with the 6‐31G(d), 6‐31G(d,p), 6‐31+G(d,p), and 6‐311+G(d,p) basis sets have been used to study the mechanism of conformational interconversion of 5,5‐dimethyl‐1,2,3‐trithiacyclohexane (5,5‐dimethyl‐1,2,3‐trithiane). The relative energies, enthalpies, entropies, free energies, and structural parameters of the chair, 1,4‐twist, and 2,5‐twist conformers, the 1,4‐boat transition state, and the 2,5‐boat transition state were calculated. B3LYP/6‐31+G(d,p) calculated the chair conformer of 5,5‐dimethyl‐1,2,3‐trithiane to be 8.38 and 8.72 kcal/mol, respectively, lower in energy than the 1,4‐twist and 2,5‐twist conformers. The energy differences (ΔE) between the chair conformer of 5,5‐dimethyl‐1,2,3‐trithiane and the 1,4‐boat transition state and the 2,5‐boat transition state were 8.95 and 11.46 kcal/mol, respectively. Intrinsic reaction coordinate [IRC, minimum energy path (MEP)] calculations were used to connect the transition state between the chair conformer and 2,5‐twist conformer. B3LYP/6‐31+G(d,p) calculated energy differences (ΔE) between the chair conformer and the transition state [TS‐1]‡ connecting the chair and 2,5‐twist conformers to be 14.23 kcal/mol. In the chair, 1,4‐twist, and 2,5‐twist conformers, the C4Heq bond is slightly longer than the C4Hax bond. The C5C8eq bond is longer than the C5C7ax bond in the chair and 1,4‐twist conformers. In the 1,4‐twist conformer, the S1S2 bond is longer than the S3S3 bond and the S1C6 bond is longer than the S3C4 bond. © 2003 Wiley Periodicals, Inc. Int J Quantum Chem, 2004
Electron transport throughout the DNA base pair
Authors: Yanov Ilya , Leszczynski Jerzy
Published: December 2003

We present here the results of a semiempirical nonequilibrium Green's function study of the electron transport properties of the adenine–thymine DNA base pair. Current‐voltage dependence I(V), conductance spectrum G(V), and transmission coefficients are calculated. The influence of the hydrogen bonds on the resistance of the base pair is discussed. The obtained results are compared with the data for the benzene‐1,4‐dithiolate molecule. It is shown that although the overall conductance of the DNA base pair is much smaller than in the case of benzene‐1,4‐dithiolate it exhibits significant conductance at small voltage biases that gives a natural way to construct wires, switches, and diodes using the single DNA molecule. © 2003 Wiley Periodicals, Inc. Int J Quantum Chem, 2004