bluuebunny/crossref_metadata_2025 huggingface dataset:
Capacitance Extraction
Authors: Yu Wenjian , Wang Zeyi
Published: April 2005

With the advances in integrated circuit (IC) technology, the effects of electromagnetic coupling among the metal interconnect lines have greatly influenced circuit performance in both VLSI circuits and microwave ICs. Therefore, the modeling and accurate extraction of interconnect capacitance has become a subject of advanced research in these fields. In this article, the fundamental theory, contemporary methodology, and algorithms of capacitance extraction are presented. First, the electrostatic basis of the capacitor is introduced and the capacitance for a multiconductor system is defined. Then, the practical methodologies of capacitance extraction for VLSI interconnects are presented, ranging from 1D, 2D, 2.5D to 3D methods and including the technique used for the task of current full‐chip extraction. Various numerical techniques of 3D capacitance extraction are discussed, some of which represent the frontier of this research field. For 3D capacitance extraction, the state of the art in fast boundary‐element methods and semianalytical approaches are surveyed, with a fairly complete list of references. Finally, some future tends on capacitance extraction are discussed.
Monolithic Antennas
Authors: Rydberg Anders , Öjefors Erik
Published: April 2005

The design of monolithic antennas for manufacturing using primarily silicon‐based technologies is presented in this article, with emphasis on space‐efficient, low‐gain antennas suitable for integration in active‐device processes. Different micromachining methods for improving the performance of the integrated antennas are considered.
Active Filters: Tools and Techniques for Active Filter Design
Authors: Billonnet Laurent , Jarry Bernard , Barelaud Bruno
Published: April 2005

In this article, we first discuss the use of CAD tools for microwave and RF filter design. We emphasize that, without any strong microwave design background and experience, optimization tools unavoidably lead to nonreproducible solutions. We then show the necessary implementation of analytical procedures to set and verify some essential characteristics of low‐noise active devices, with the examples of electrical stability criteria and noise performance calculation, prediction, and optimization. Section 2 deals with the description of tools and techniques for filter improvements. We begin with an extended consideration of compensation techniques based on response selectivity and circuit dimensions improvement. The technique is illustrated with the design of a one‐pole interdigital filter and a two‐pole coplanar filter whose response and size have been improved using this approach. We then generalise the principle to the active‐impedance profile (AIP ) technique, which is illustrated with the application to multistandard and pseudomultipole filters. Finally, novel approaches and new technologies for new microwave and RF communications needs are detailed. We confront GaAs processes to silicon‐based technologies in terms of processes themselves, and in terms of CAD tools, component implementation, compactness, relative size, and cost with two basic circuit examples. Migration to silicon‐based processes also involves novel implementation approaches, including differential circuits. This last approach is illustrated with experimental results.
Analytical and Adaptive Modeling of Nonlinear High Power Amplifiers
Authors: Ibnkahla Mohamed
Published: April 2005

High‐power amplifiers are used in modern communication systems for their high‐power efficiency. However, these amplifiers have generally nonlinear characteristics, leading to signal distortion and adjacent channel interference. We review the most popular analytical models for these nonlinear characteristics. A special focus is given to adaptive models—mainly neural network approaches—which have emerged as efficient tools for the modeling, identification, and characterization of nonlinear amplifiers.
Effect of metal salt of ethylene/methacrylic acid copolymer on electron beam crosslinking of low density polyethylene
Authors: Ali Z. I. , Legocka I.
Published: April 2005

A thermoplastic resin based on ethylene/methacrylic acid copolymer (EMA) was used as a modifier for different low density polyethylene (LDPE) batches under the effect of electron beam irradiation. The EMA resin was used in the zinc metal form at a constant ratio of 9 wt% in all preparations. The effect of EMA resin as a crosslinking agent was characterized by percentage gel fraction, tensile mechanical, and differential scanning calorimetry (DSC). In this study, the maximum gel content (Gmax) and gelling dose (Dgel) parameters were determined by applying the familiar Charlesby–Pinner relationship. The results showed that the gel content for all investigated samples gradually increases with increasing irradiation dose. The modified LDPE batches with EMA show higher gel content than unmodified ones at any irradiation dose. Also, the gel content of all LDPE composites decreases as a result of post‐storage effect. The mechanical properties (tensile strength and elongation at break) exhibit significant change as a result of irradiation and blending the LDPE batch with EMA. The level of change in mechanical properties seems to be more pronounced for EMA‐modified LDPE batches. © 2005 Wiley Periodicals, Inc. Adv Polym Techn 24:103–113, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/adv.20034
Improvement of paper strength with starch modified clay
Authors: Yan Zegui , Liu Qiujuan , Deng Yulin , Ragauskas Arthur
Published: April 2005

In order to improve the strength properties of high filler filled papers, a new technique of coating starch on the clay surface was developed. The stability of the coated starch and its effects on paper properties were studied. It was found that the starch coated on the clay surface swelled in water. This swelled starch film on the filler surface contributes significantly to the filler–filler bonding. The strength properties of handsheets made from starch coated clay, even with unmodified corn starch, could be increased by more than 15% versus those from the traditional method of adding cationic or amphoteric potato starch directly to 50% bleached softwood pulp/50% bleached hardwood pulp. This research suggests that the starch coated filler can be used to make high filler content paper products. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 44–50, 2005
Dose‐independent pharmacokinetics of torasemide after intravenous and oral administration to rats
Authors: Lee Dae Y. , Kim Ji Y. , Kim Yu C. , Kwon Jong W. , Kim Won B. , Lee Myung G.
Published: April 2005

After intravenous (at doses of 1, 2, 5, and 10 mg/kg) and oral (at doses of 1, 5, and 10 mg/kg) administration of torasemide, the pharmacokinetic parameters were dose‐independent. Hence, the extent of absolute oral bioavailability (F) was also independent of oral doses; the values were 95.6, 98.8, and 97.3% for oral doses of 1, 5, and 10 mg/kg, respectively. The high F values indicated that the first‐pass (gastric, intestinal, and hepatic) effects of torasemide in rats could be almost negligible. After intravenous administration, the total body clearances of torasemide were extensively slower than the reported cardiac output in rats and hepatic extraction ratio was only 3–4% suggesting almost negligible first‐pass effects of torasemide in the heart, lung, and liver in rats. Based on in vitro rat tissue homogenate studies, the tissues studied also showed negligible metabolic activities for torasemide. Equilibrium of torasemide between plasma and blood cells of rat blood reached fast and plasma‐to‐blood cells concentration ratio was independent of initial blood concentrations of torasemide, 1, 5, and 10 µg/ml; the mean value was 0.279. Protein binding of torasemide to fresh rat plasma was 93.9±1.53% using an equilibrium dialysis technique. Copyright © 2005 John Wiley & Sons, Ltd.
Adsorption of poly(ethylene glycol)‐modified ribonuclease A to a poly(lactide‐co‐glycolide) surface
Authors: Daly Susan M. , Przybycien Todd M. , Tilton Robert D.
Published: April 2005

Protein adsorption is a source of variability in the release profiles of therapeutic proteins from biodegradable microspheres. We employ optical reflectometry and total internal reflection fluorescence to explore the extent and kinetics of ribonuclease A (RNase A) adsorption to spin‐cast films of poly(lactide‐co‐glycolide) (PLG) and, in particular, to determine how covalent grafting of polyethylene glycol (PEG) to RNase A affects adsorption. Adsorption kinetics on PLG surfaces are surface‐limited for RNase A but transport‐limited for unconjugated PEG homopolymers and for PEG‐modified RNase A, indicating that PEG anchors the conjugates to the surface during the transport‐limited regime. PEG modification of RNase A decreases the total number of adsorbed molecules per unit area but increases the areal surface coverage because the grafted PEG chains exclude additional surface area. Total internal reflection fluorescence‐based exchange measurements show that there is no exchange between adsorbed and solution‐phase protein molecules. This indicates an unusually tenacious adsorption. Streaming current measurements indicate that the ζ potential of the PLG surface becomes increasingly negative as the film is exposed to water for several weeks, as expected. Aging of the PLG surface results in increased adsorption of unmodified RNase A but decreased adsorption of unconjugated PEG homopolymers and of PEG–RNase A conjugates, relative to the extent of adsorption on freshly prepared PLG surfaces. Adsorption results correlate well with an increase in the rate, total extent and preservation of bioactivity of RNase A released from PLG microspheres for the PEG‐modified version of RNase A. © 2005 Wiley Periodicals, Inc.
Are business students buying it? A theoretical framework for measuring attitudes toward the legitimacy of environmental sustainability
Authors: Thomas Tom E.
Published: April 2005

Environmental sustainability has begun to penetrate the business school curriculum. Whether it ultimately becomes a key component of managerial decision‐making models will depend upon whether it is perceived as legitimate within the context of profit‐making enterprises. This paper draws upon the cognitive psychology and organizational legitimacy literatures to develop a conceptual framework for operationalizing perceived legitimacy. This framework can be used to develop survey instruments and simulations that evaluate the effectiveness of various pedagogical approaches to integrating sustainability into business school curricula. Copyright © 2005 John Wiley & Sons, Ltd and ERP Environment.
‘Education for sustainability’ in the business studies curriculum: a call for a critical agenda
Authors: Springett Delyse
Published: April 2005

The critical theorization of education for sustainability developed from the earlier political conception of ‘education for the environment’. This critical perspective underpins the theory of education for sustainability that the paper introduces, and informs the goals, structure and content of the post‐graduate course that it describes. It is posited that education for sustainability challenges the ‘rationality’ of the capitalist paradigm of production and consumption, thereby providing a challenge for the tertiary curriculum in general and for the business curriculum in particular. A ‘window’ is provided on the way in which theory drives the narrative of sustainability in the course, ‘Business and Sustainability’, and a brief overview of the course introduces the pedagogical approach based in action methods as well as insights from student self‐reflection and course evaluation. Copyright © 2005 John Wiley & Sons, Ltd and ERP Environment.
Ring‐Closing Olefin Metathesis on Ruthenium Carbene Complexes: Model DFT Study of Stereochemistry
Authors: Vyboishchikov Sergei F. , Thiel Walter
Published: April 2005

Ring‐closing metathesis (RCM) is the key step in a recently reported synthesis of salicylihalamide and related model compounds. Experimentally, the stereochemistry of the resulting cycloolefin (cis/trans) depends strongly on the substituents that are present in the diene substrate. To gain insight into the factors that govern the observed stereochemistry, density functional theory (DFT) calculations have been carried out for a simplified dichloro(2‐propylidene)(imidazole‐2‐ylidene)ruthenium catalystI, as well as for the real catalystIIwith two mesityl substituents on the imidazole ring. Four model substrates are considered, which are closely related to the systems studied experimentally, and in each case, two pathways A and B are possible since the RCM reaction can be initiated by coordination of either of the two diene double bonds to the metal center. The first metathesis yields a carbene intermediate, which can then undergo a second metathesis by ring closure, metallacycle formation, and metallacycle cleavage to give the final cycloolefin complex. According to the DFT calculations, the stereochemistry is always determined in the second metathesis reaction, but the rate‐determining step may be different for different catalysts, substrates, and pathways. The ancillary N‐heterocyclic carbene ligand lies in the Ru‐Cl‐Cl plane in the simplified catalystI, but is perpendicular to it in the real catalystII, and this affects the relative energies of the relevant intermediates and transition states. Likewise, the introduction of methyl substituents in the diene substrates influences these relative energies appreciably. Good agreement with the experimentally observed stereochemistry is only found when using the real catalystIIand the largest model substrates in the DFT calculations.
The Experiences of Sleep Disruption in Families of Technology‐dependent Children Living at Home
Authors: Heaton Janet , Noyes Jane , Sloper Patricia , Shah Robina
Published: April 2005

This paper examines the sleep disruption experienced by 36 families of technology‐dependent children living at home in the United Kingdom. The paper begins with an overview of the qualitative study in which parents' experiences of sleep disruption emerged as a major theme. We then describe the nature of and reasons for the sleep disruption, the help families received with care overnight, and the effects of sleep disruption on parents in particular. This is followed by discussion of the implications of the findings for policy and practice as well as future research.
Synthesis and Crystal Structure of (Sb2Te2)[AlCl4], a Compound Containing a Heteroatomic Polymeric Cation (Sb2Te2+)n.
Authors: Beck Johannes , Schlueter Stefan
Published: April 2005

For Abstract see ChemInform Abstract in Full Text.
Synthesis, Structural and Magnetic Characterization of a New Scheelite Related Compound: Eu2Mo3O12.
Authors: Boulahya Khalid , Parras Marina , Gonzalez‐Calbet Jose M.
Published: April 2005

For Abstract see ChemInform Abstract in Full Text.
Oxidation of CO by SO2: A Theoretical Study
Authors: Bacskay George B. , Mackie John C.
Published: April 2005

For Abstract see ChemInform Abstract in Full Text.
Spiro‐heterocycles from Substituted Pyridines, Pyrans and Thiopyrans.
Authors: Padmavathi Venkatapuram , Reddy Boggu Jagan Mohan , Reddy Boreddy Chandra Obula , Padmaja Adivireddy
Published: April 2005

For Abstract see ChemInform Abstract in Full Text.
Highly Efficient Beckmann Rearrangement and Dehydration of Oximes.
Authors: Li Dongmei , Shi Feng , Guo Shu , Deng Youquan
Published: April 2005

For Abstract see ChemInform Abstract in Full Text.
Ytterbium(III) Triflate‐Catalyzed Conversion of Carbonyl Compounds into 1,3‐Oxathiolanes in Ionic Liquids.
Authors: Kumar Anil , Jain Nidhi , Rana Sandeep , Chauhan Shive M. S.
Published: April 2005

For Abstract see ChemInform Abstract in Full Text.
Oxidative Cleavage of C—Si Bonds in Polyhydroxylated Silacyclopentanes.
Authors: Landais Yannick , Mahieux Cedrick
Published: April 2005

For Abstract see ChemInform Abstract in Full Text.
The First Example of Magnesium Carbenoid 1,3‐CH Insertion Reaction: A Novel Method for Synthesis of Cyclopropanes from 1‐Chloroalkyl Phenyl Sulfoxides in High Yields.
Authors: Satoh Tsuyoshi , Musashi Jun , Kondo Atsushi
Published: April 2005

For Abstract see ChemInform Abstract in Full Text.
Ring Expansion‐Annulation Strategy for the Synthesis of Substituted Azulenes and Oligoazulenes. Part 2. Synthesis of Azulenyl Halides, Sulfonates, and Azulenylmetal Compounds and Their Application in Transition‐Metal‐Mediated Coupling Reactions.
Authors: Crombie Aimee L. , Kane John L. Jr. , Shea Kevin M. , Danheiser Rick L.
Published: April 2005

For Abstract see ChemInform Abstract in Full Text.
A Convenient and Efficient Route for the Allylation of Aromatic Amines and α‐Aryl Aldehydes with Alkynes in the Presence of a Pd(0)/PhCOOH Combined Catalyst System.
Authors: Patil Nitin T. , Wu Huanyou , Kadota Isao , Yamamoto Yoshinori
Published: April 2005

For Abstract see ChemInform Abstract in Full Text.
Rhenium Complex‐Catalyzed Allylation of Aldehydes with Allyltributylstannane.
Authors: Nishiyama Yutaka , Kakushou Fujio , Sonoda Noboru
Published: April 2005

For Abstract see ChemInform Abstract in Full Text.
Stereoselective Enol Tosylation: Preparation of Trisubstituted α,β‐Unsaturated Esters.
Authors: Baxter Jenny M. , Steinhuebel Dietrich , Palucki Michael , Davies Ian W.
Published: April 2005

For Abstract see ChemInform Abstract in Full Text.
Regiospecific Topochemical Reactions Controlled by Trifluoromethyl Directing Groups.
Authors: Liu Jin , Boarman Kelly Jo
Published: April 2005

For Abstract see ChemInform Abstract in Full Text.
Synthesis of Butyrolactones by Nickel‐Catalyzed Reductive Cyanation of Alkynols in Water.
Authors: Garcia Gutierrez Jose Luis , Jimenez‐Cruz Federico , Espinosa Noe Rosas
Published: April 2005

For Abstract see ChemInform Abstract in Full Text.
Efficient Synthesis of Novel Polyfunctionalized 4,5′‐Bithiazol‐4′‐ol Derivatives.
Authors: Arcadi Antonio , Attanasi Orazio A. , Filippone Paolino , Perrulli Francesca R. , Rossi Elisabetta , Santeusanio Stefania
Published: April 2005

For Abstract see ChemInform Abstract in Full Text.
Synthesis of 4‐Heteroaryl‐Substituted Coumarins by Suzuki Cross‐Coupling Reactions.
Authors: Beletskaya Irina P. , Ganina Olga G. , Tsvetkov Alexey V. , Fedorov Alexey Yu. , Finet Jean‐Pierre
Published: April 2005

For Abstract see ChemInform Abstract in Full Text.
Alkyl Heterocycles in Heterocyclic Synthesis. Part 2. Novel Synthesis of Isoquinoline, Thiazolopyridine, and Thieno[2,3‐b]pyridine Derivatives.
Authors: Elmaati Tarek M. Abu
Published: April 2005

For Abstract see ChemInform Abstract in Full Text.
Pyrrolodiazines. Part 6. Palladium‐Catalyzed Arylation, Heteroarylation, and Amination of 3,4‐Dihydropyrrolo[1,2‐a]pyrazines.
Authors: Castellote Isabel , Vaquero Juan J. , Fernandez‐Gadea Javier , Alvarez‐Builla Julio
Published: April 2005

For Abstract see ChemInform Abstract in Full Text.
A Convenient Route to Imino Sugars and Analogues of Siastatin B (X).
Authors: Birch Nicola J. , Parsons Phillip J. , Scopes David I. C.
Published: April 2005

For Abstract see ChemInform Abstract in Full Text.
An Anionic Polycondensation Strategy for the Synthesis of Dibenzoxanthenones: Progress Toward the Synthesis of Hypoxyxylerone.
Authors: Chevenier Emmanuel , Lucatelli Christophe , Pandya Urvish , Wang Wei , Gimbert Yves , Greene Andrew E.
Published: April 2005

For Abstract see ChemInform Abstract in Full Text.
Synthesis and Melanin Biosynthesis Inhibitory Activity of (.+‐.)‐Terrein Produced by Penicillium sp. 20135.
Authors: Lee Sangku , Kim Won‐Gon , Kim Eungsoo , Ryoo In‐Ja , Lee Hyeong Kyu , Kim Jae Nyoung , Jung Sang‐Hun , Yoo Ick‐Dong
Published: April 2005

For Abstract see ChemInform Abstract in Full Text.
Synthesis and Schistosomicidal Activity of New Substituted Thioxo‐Imidazolidine Compounds.
Authors: Pitta I. R. , et al. et al.
Published: April 2005

For Abstract see ChemInform Abstract in Full Text.
Low‐Temperature Synthesis of Nanocrystalline Niobium Nitride via a Benzene‐Thermal Route.
Authors: Ma Jianhua , Du Yihong , Qian Yitai
Published: April 2005

For Abstract see ChemInform Abstract in Full Text.
Molecular Design of Synthetic Receptors with Dynamic, Imprinting, and Allosteric Functions
Authors: Shinkai Seiji , Takeuchi Masayuki
Published: April 2005

For Abstract see ChemInform Abstract in Full Text.
Silylhydroxylamines: Synthesis, Isomerization, and Quantum Chemical Calculations
Authors: Ebker Christina , Diedrich Friedhelm , Schmatz Stefan , Klingebiel Uwe
Published: April 2005

For Abstract see ChemInform Abstract in Full Text.
Polyfunctionalized Tetrathiafulvalenes for Advanced Materials
Authors: Gorgues A.
Published: April 2005

For Abstract see ChemInform Abstract in Full Text.
Molecular Complexes of Water‐Soluble Porphyrins
Authors: Kano Koji
Published: April 2005

For Abstract see ChemInform Abstract in Full Text.
Recent Developments of Acid—Base Catalysis in Organic Chemistry
Authors: Figueras Francois
Published: April 2005

For Abstract see ChemInform Abstract in Full Text.
Structure, Orientation, and Conformational Changes in Transmembrane Domains of Multidrug Transporters
Authors: Vigano Catherine , Manciu Liliana , Ruysschaert Jean‐Marie
Published: April 2005

For Abstract see ChemInform Abstract in Full Text.
Optical Microscopy Studies of Dynamics within Individual Polymer‐Dispersed Liquid Crystal Droplets
Authors: Higgins Daniel A. , Hall Jeffrey E. , Xie Aifang
Published: April 2005

For Abstract see ChemInform Abstract in Full Text.
Hyperolactone C: Determination of its absolute configuration by comparison of experimental and calculated CD spectra
Authors: Schühly Wolfgang , Crockett Sara L. , Fabian Walter M.F.
Published: April 2005

A detailed conformational analysis of hyperolactone C diastereomers and enantiomers ((5R,9R),(5S,9S) and (5S,9R),(5R,9S)) was done with molecular mechanics and density functional theory methods. Time‐dependent density functional theory (B3PW91/TZVP) was used to calculate electronic transition energies (UV/vis spectra) and rotational strengths of the respective conformations. The effect of solvation (acetonitrile solution) on excitation energies and electronic circular dichroism was approximated by the polarizable continuum model. By comparison of the simulated CD spectrum with that measured for hyperolactone C isolated from Hypericum lloydii, its absolute configuration can be assigned as (5S,9S). Chirality 17:250–256, 2005. © 2005 Wiley‐Liss, Inc.
Studying the emerging global brain: Analyzing and visualizing the impact of co‐authorship teams
Authors: Börner Katy , Dall'Asta Luca , Ke Weimao , Vespignani Alessandro
Published: April 2005

This article introduces a suite of approaches and measures to study the impact of co‐authorship teams based on the number of publications and their citations on a local and global scale. In particular, we present a novel weighted graph representation that encodes coupled author‐paper networks as a weighted co‐authorship graph. This weighted graph representation is applied to a dataset that captures the emergence of a new field of science and comprises 614 articles published by 1036 unique authors between 1974 and 2004. To characterize the properties and evolution of this field, we first use four different measures of centrality to identify the impact of authors. A global statistical analysis is performed to characterize the distribution of paper production and paper citations and its correlation with the co‐authorship team size. The size of co‐authorship clusters over time is examined. Finally, a novel local, author‐centered measure based on entropy is applied to determine the global evolution of the field and the identification of the contribution of a single author's impact across all of its co‐authorship relations. A visualization of the growth of the weighted co‐author network, and the results obtained from the statistical analysis indicate a drift toward a more cooperative, global collaboration process as the main drive in the production of scientific knowledge. © 2005 Wiley Periodicals, Inc. Complexity 10: 57–67, 2005
Influence of preparation conditions on the properties of Eudragit microspheres produced by a double emulsion method
Authors: Sipos Péter , Csóka Ildikó , Srčič Stane , Pintye‐Hódi Klára , Erős István
Published: April 2005

The aim of the present work was to study the preparation and characteristics of sustained‐release microspheres. As a model drug, sodium diclofenac was encapsulated in microspheres of the polymer Eudragit RS by using a double emulsion–solvent evaporation method. Investigations were carried out on the effects of the preparation method, the rate of the first step of emulsification, and the phase volume and composition (drug and additives) on the physical parameters of the product: its drug encapsulation, and the drug release. We evaluated the resulting microsphere structure [by differential scanning calorimetry (DSC)], the particle size, the surface area (by scanning electron microscopy), the entrapment and encapsulation efficiency (applying a novel method, energy‐dispersive x‐ray fluorescence analysis), the viscosity of the primary emulsion, and the organic solvent residue (by gas chromatography). We also evaluated and compared the samples by means of the kinetic data relating to drug release. The particle size could be decreased to one third by increasing the external aqueous phase ratio. In the first step of emulsification, elevation of the stirring rate led to microspheres with unfavorable characteristics. Increase of the active agent content and the plasticizer concentration had opposite effects. We applied a covalently not bound plasticizer, which was shown to influence the structure of the microspheres considerably. Drug Dev. Res. 64:41–54, 2005. © 2005 Wiley‐Liss, Inc.
Physicochemical Properties of Oosporein, the Major Secreted Metabolite of the Entomopathogenic Fungus Beauveria brongniartii
Authors: Seger Christoph , Erlebach Daniela , Stuppner Hermann , Griesser Ulrich J. , Strasser Hermann
Published: April 2005

Oosporein (1) is the major secondary metabolite excreted by Beauveria brongniartii (Sacc.) Petch (Ascomycota: Clavicipitaceae), an entomopathogenic fungus infesting the larvae of Melolontha melolontha L. (Coleoptera: Scarabaeidae; common European cockchafer). Physicochemical parameters were established to allow a better understanding of the spatiotemporal distribution of this marker substance in the environment. i) The dependence of the oosporein solubility (Cs) from proton concentration and temperature was assessed. Oosporein is a rather strong organic acid. The basal solubility of oosporein (C in aqueous citrate/HCl buffer at pH 1.23) was found to be 24.8±0.3 μM. The pKa of the first deprotonation step was determined to be 2.42±0.02. A nonlinear van't Hoff equation was established for the temperature dependency of the oosporein solubility (lnCs=a+bT−1+clnT, with a=−123.3, b=2678.9, and c=19.5). ii) A second and third deprotonation step was found in Britton–Robinson‐buffered aqueous solution. The associated pKa values were determined as 6.79±0.08 and 9.19±0.03. iii) The stability of oosporein at different pH values and temperatures was addressed. Oosporein degraded quickly under moderate alkaline conditions and with increased temperatures. The half‐life dropped below 20 h at pH≥8.0 and T≥43°. The analysis of the Arrhenius plot allowed to calculate the activation energies (Ea) as 102±17 (pH 6), 100±5 (pH 8), and 91±6 kJ/mol (pH 10). iiii) The octanol/water partition coefficient (PO) and its pH dependence were also determined. The distribution coefficient (DO) for oosporein at pH 1.2 was found to be 53.7±4.1 (logDO=1.73±0.03). The partition coefficient PO for undissociated oosporein was calculated as 56.6 (logPO=1.75). From the physicochemical properties, it can be concluded that oosporein can hardly be adsorbed by organisms.
Potential Anti‐Inflammatory Activities of Bractelactone and other Compounds Isolated from Fissistigma bracteolatum
Authors: Lan Yu‐Hsuan , Chia Yi‐Chen , Chang Fang‐Rong , Hwang Tsong‐Long , Liaw Chih‐Chaung , Wu Yang‐Chang
Published: April 2005

From the stems of Fissistigma bracteolatum, a novel natural product with an unprecedented skeleton, bractelactone (1), was isolated, together with four known compounds: piperolactam A (2), aristololactam BIII (3), aristololactam BII (4), and fissilandione (5). The structure of 1 was established on the basis of spectroscopic data as (3Z)‐6,7‐dihydroxy‐4‐methoxy‐3‐(phenylmethylidene)‐5‐(3‐phenylpropanoyl)‐1‐benzofuran‐2(3H)‐one. This compound may be derived from a hybrid of a chalcone and a cinnamic acid, or from a degradation product of a dichalcone. Compounds 1, 2, and 5 showed inhibitory effects on NO generation by RAW264.7 macrophages in response to lipopolysaccharide. Compounds 2 and 5 showed inhibitory effects on formyl‐L‐methionyl‐L‐leucyl‐L‐phenylalanine (fMLP)‐induced superoxide anion (O$\rm{_{2}^{{^\cdot} -}}$) generation in human neutrophils.
Sediment delivery from agricultural land to rivers via subsurface drainage
Authors: Chapman A. S. , Foster I. D. L. , Lees J. A. , Hodgkinson R. A.
Published: April 2005

Diffuse sources of sediment and sediment‐associated nutrients are of increasing environmental concern because of their impacts on receiving water courses. The aim of the research reported here was to monitor the outflow from four field (land) drains at two farms in the English Midlands in order to estimate the quantity of sediment delivered to the local rivers and the most likely sources and processes involved. A multiparameter sediment unmixing model was employed, using environmental magnetic, geochemical and radionuclide tracers in order to determine the most likely origin of sediments transported through the drains. Results demonstrated that there was a generally linear relationship between drainflow sediment loss and drainflow volume and that the majority (>70%) of the sediment exported from the drains was derived from topsoil. Macropore flow through heavily cracked soils is supported by the data to be the most likely means of sediment delivery to the drains. In one catchment, drains contributed over 50% of the annual sediment budget. Spatial and temporal variations in the sources of sediment reaching one drain outlet were investigated in detail. A link between soil moisture deficit (SMD) and the frequency of high‐intensity rainfall events was used to explain the appearance and persistence of a new sediment source in this drain after October 1998. It is concluded that field drains have the potential to be significant conduits of sediment and agrochemicals in a wide variety of environments in the UK. It is also suggested that this potential may increase if projected climate change leads to more intense rainfall events and increases in SMD across a greater area of the UK. Copyright © 2005 John Wiley & Sons, Ltd.
Retracted and replaced: A modelling study of hyporheic exchange pattern and the sequence, size, and spacing of stream bedforms in mountain stream networks, Oregon, USA
Authors: Gooseff Michael N. , Anderson Justin K. , Wondzell Steven M. , LaNier Justin , Haggerty Roy
Published: April 2005

This article has been retracted and replaced. See Retraction and Replacement Notice DOI: 10.1002/hyp.6350

Studies of hyporheic exchange flows have identified physical features of channels that control exchange flow at the channel unit scale, namely slope breaks in the longitudinal profile of streams that generate subsurface head distributions. We recently completed a field study that suggested channel unit spacing in stream longitudinal profiles can be used to predict the spacing between zones of upwelling (flux of hyporheic water into the stream) and downwelling (flux of stream water into the hyporheic zone) in the beds of mountain streams. Here, we use two‐dimensional groundwater flow and particle tracking models to simulate vertical and longitudinal hyporheic exchange along the longitudinal axis of stream flow in second‐, third‐, and fourth‐order mountain stream reaches. Modelling allowed us to (1) represent visually the effect that the shape of the longitudinal profile has on the flow net beneath streambeds; (2) isolate channel unit sequence and spacing as individual factors controlling the depth that stream water penetrates the hyporheic zone and the length of upwelling and downwelling zones; (3) evaluate the degree to which the effects of regular patterns in bedform size and sequence are masked by irregularities in real streams. We simulated hyporheic exchange in two sets of idealized stream reaches and one set of observed stream reaches. Idealized profiles were constructed using regression equations relating channel form to basin area. The size and length of channel units (step size, pool length, etc.) increased with increasing stream order. Simulations of hyporheic exchange flows in these reaches suggested that upwelling lengths increased (from 2·7 m to 7·6 m), and downwelling lengths increased (from 2·9 m to 6·0 m) with increase in stream order from second to fourth order. Step spacing in the idealized reaches increased from 5·3 m to 13·7 m as stream size increased from second to fourth order. Simulated upwelling lengths increased from 4·3 m in second‐order streams to 9·7 m in fourth‐order streams with a POOL–RIFFLE–STEP channel unit sequence, and increased from 2·5 m to 6·1 m from second‐ to fourth‐order streams with a POOL–STEP–RIFFLE channel unit sequence. Downwelling lengths also increased with stream order in these idealized channels. Our results suggest that channel unit spacing, size, and sequence are all important in determining hyporheic exchange patterns of upwelling and downwelling. Though irregularities in the size and spacing of bedforms caused flow nets to be much more complex in surveyed stream reaches than in idealized stream reaches, similar trends emerged relating the average geomorphic wavelength to the average hyporheic wavelength in both surveyed and idealized reaches. Copyright © 2005 John Wiley & Sons, Ltd.
Content‐aware full search scheme for motion estimation
Authors: Huang Shih‐Yu
Published: April 2005

Taking into consideration computational complexity and design regularity, this article proposes a content‐aware full search (CAFS) block matching scheme for motion estimation. Full search (FS) is widely employed in hardware design of block matching because of its regular data flow. But the huge computational complexity of FS makes it infeasible especially in low‐power environments. To reduce the required computational complexity, CAFS using a content‐aware computation allocation mechanism dynamically distributes computation to blocks with distinct motion content based on center‐biased distribution characteristics of motion vectors. Because all operations of CAFS can be performed by a series of ±2 FSs, the hardware of CAFS can be easily extended by the design of FS. Experimental results indicates that CAFS can achieve about 0.5–1.4 dB quality improvement over original FS in football and table tennis sequences under the same computation. © 2005 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 14, 246–252, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ima.20028
Holographic digital Fourier microscopy for selective imaging of biological tissue
Authors: Alexandrov Sergey A. , Meredith P. , McIntyre T. J. , Zvyagin A. V.
Published: April 2005

We present an application of digital Fourier holography for selective imaging of scatterers with different sizes in turbid media such as biological tissues. A combination of Fourier holography and high‐resolution digital recording, digital Fourier microscopy (DFM) permits crucial flexibility in applying filtering to highlight scatterers of interest in the tissue. The high‐resolution digital hologram is a result of the collation of Fourier holographic frames to form a large‐size composite hologram. It is expected that DFM has an improved signal‐to‐noise ratio as compared to conventional direct digital imaging, e.g., phase microscopy, as applied to imaging of small‐size objects. The demonstration of the Fourier filtering capacity of DFM using a biological phantom represents the main focus of this article. © 2005 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 14, 253–258, 2004; Published online inWiley InterScience (www.interscience.wiley.com). DOI 10.1002/ima.20031
An accurate relativistic universal Gaussian basis set for hydrogen through Nobelium without variational prolapse and to be used with both uniform sphere and Gaussian nucleus models
Authors: Haiduke Roberto L. A. , de Macedo Luiz G. M. , da Silva Albérico B. F.
Published: April 2005

An accurate relativistic universal Gaussian basis set (RUGBS) from H through No without variational prolapse has been developed by employing the Generator Coordinate Dirac–Fock (GCDF) method. The behavior of our RUGBS was tested with two nuclear models: (1) the finite nucleus of uniform proton‐charge distribution, and (2) the finite nucleus with a Gaussian proton‐charge distribution. The largest error between our Dirac–Fock–Coulomb total energy values and those calculated numerically is 8.8 mHartree for the No atom. © 2005 Wiley Periodicals, Inc. J Comput Chem 26: 932–940, 2005
Prediction of numbing and effortful avoidance in female rape survivors with chronic PTSD
Authors: Feuer Catherine A. , Nishith Pallavi , Resick Patricia
Published: April 2005

The purpose of the present study was to investigate the relationships among numbing, arousal, intrusion, and avoidance in a sample of 272 female rape survivors. Multiple regression analyses were conducted to test a theoretical model, which posits that hyperarousal and numbing are functionally related mechanisms and intrusions and avoidance are functionally related. Results supported the hypothesis that arousal explained the majority of the variance in numbing beyond that explained by avoidance and intrusion. In addition, intrusive symptoms explained the majority of the variance in effortful avoidance beyond that explained by numbing and arousal. The findings suggest that numbing and effortful avoidance may be separate mechanisms associated with symptoms of arousal and intrusion, respectively.
Synthesis and Hydrolysis of α,ω‐Perfluoroalkyl‐Functionalized Derivatives of Poly(ethylene oxide)
Authors: Amado Elkin , Kressler Jörg
Published: April 2005

Summary: Two series of novel α,ω‐perfluoroalkyl terminated esters of poly(ethylene oxide) (PEO) (RF‐PEO) having the general structure CmF2m+1COO(CH2CH2O)nOCCmF2m+1, with m = 1,2,3,4 or 5 have been synthesized. The influences of the PEO molar mass, the length of the perfluoroalkyl group (RF) and temperature on the cleavage of the ester bridge in aqueous solution and the effect of the hydrolysis process on the size of aggregates formed in water were studied. According to 1H and 19F NMR measurements the degree of functionalization obtained (up to 96 mol‐%) increases with the decrease in the length of the RF group. All of the derivatives showed ester cleavage in water in short time scales. The rates of hydrolysis of the ester bridge in aqueous solution were determined from pH‐measurements. It was verified that the rate law for hydrolysis corresponds to a pseudo‐first order type. The hydrolysis kinetic constant k increased with a decrease in the length of the RF group ranging from 0.2 × 10−3 s−1 for the longest RF group (C5F11) up to 1.2 × 10−2 s−1 for the shortest RF group (CF3). The value of k depended almost exclusively on the length of the perfluoroalkyl chain and was independent of the length of the PEO backbone (1 000 or 2 000 g · mol−1), as long as no additional phenomenon such as phase separation was present. It was also found that the change in the value of k with temperature followed a non‐Arrhenius pattern and there was an evident relationship between the non‐linearity in the ln k vs. 1/T relation with increasing temperatures and the occurrence of a macroscopic phase separation of LCST type. Dynamic light scattering measurements showed the coexistence of unimers with associated species with apparent hydrodynamic radii (Rh) of approximately 20–45 nm for all samples in aqueous solutions. These species might correspond to aggregates of a few micelles. For some samples also larger aggregates were found with Rh in the 100–500 nm range, which might be attributed to clusters of micelles.

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Higher‐order harmonic transmission‐line RF coil design for MR applications
Authors: Zhang Xiaoliang , Zhu Xiao‐Hong , Chen Wei
Published: April 2005

A novel concept based on the use of higher‐order harmonic resonances in a transmission‐line resonator is introduced for the design of high‐frequency RF coils at high and ultrahigh fields, where conventional RF coil designs present difficulties and limitations. To demonstrate this concept, we successfully designed and fabricated a 400‐MHz RF coil for rat imaging using a second‐harmonic resonant microstrip transmission line. This coil has a high Q‐factor, reduces coil–cable interactions without the use of a matching balun, and has a broad range for tuning the coil's resonant frequency at the loaded condition. This work demonstrates that the use of higher‐order harmonics in a transmission‐line resonator provides an alternative, efficient approach to the design of large and high‐frequency RF coils. Magn Reson Med 53:1234–1239, 2005. © 2005 Wiley‐Liss, Inc.
Confidence mapping in diffusion tensor magnetic resonance imaging tractography using a bootstrap approach
Authors: Jones Derek K. , Pierpaoli Carlo
Published: April 2005

The bootstrap technique is an extremely powerful nonparametric statistical procedure for determining the uncertainty in a given statistic. However, its use in diffusion tensor MRI tractography remains virtually unexplored. This work shows how the bootstrap can be used to assign confidence to results obtained with deterministic tracking algorithms. By invoking the concept of a “tract‐propagator,” it also underlines the important effect of local fiber architecture or architectural milieu on tracking reproducibility. Finally, the practical advantages and limitations of the technique are discussed. Not only does the bootstrap allow any deterministic tractography algorithm to be used in a probabilistic fashion, but also its model‐free inclusion of all sources of variability (including those that cannot be modeled) means that it provides the most realistic approach to probabilistic tractography. Magn Reson Med 53:1143–1149, 2005. Published 2005 Wiley‐Liss, Inc.
A nonoverlapping domain decomposition method for variational inequalities derived from free boundary problems
Authors: Jiang Bin , Bruch John C. , Sloss James M.
Published: April 2005

The article proposes a nonoverlapping domain decomposition method for variational inequalities derived from free boundary problems. The free boundary value problem is broken up into two problems on nonoverlapping regions. In one region the problem is treated as a partial differential equation, while in the second region that contains the free boundary part, a variational inequality is considered. By solving these two related problems successively, we have shown that the successive solutions converge to the solution of the original problem. Application to a free surface seepage problem is given. © 2005 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq, 2006
Steric and electronic substituent effects in hydrolysis and aminolysis of 4‐alkyl‐4‐methyl‐2‐aryl‐4,5‐dihydro‐1,3‐oxazol‐5‐ones
Authors: Sedlák Miloš , Keder Roman , Skála Pavel , Hanusek Jiří
Published: April 2005

The kinetics and mechanism of the acid‐catalysed hydrolysis of substituted 4‐alkyl‐4‐methyl‐2‐aryl‐4,5‐dihydro‐1,3‐oxazol‐5‐ones to the corresponding 2‐alkyl‐2‐benzoylaminopropanoic acids were studied. The Taft correlation of rate constants of the acid‐catalysed hydrolysis with alkyl substitution at the 4‐position of the 1,3‐oxazol‐5‐one ring is non‐linear. In the Hammett correlation, the value of ρ decreases with increasing steric demand of the alkyl substituent. With the 4‐isopropyl and tert‐butyl derivatives, ρ = − 0.63 and − 0.32, respectively. The protonated 4‐isopropyl and tert‐butyl derivatives undergo nucleophilic attack by water at the carbonyl carbon atom at the 5‐position of the 1,3‐oxazol‐5‐one ring to the extents of ca 70% and 60%, respectively. Another reaction path consists in nucleophilic attack by water at the 2‐position of the 1,3‐oxazol‐5‐one ring. The reaction kinetics of aminolyses of substituted 4‐isopropyl‐4‐methyl‐2‐phenyl‐1,3‐oxazol‐5(4H)‐ones (1a, 1b, 1f) giving substituted N‐{1,2‐dimethyl‐1‐[(propylamino)carbonyl]‐propyl}benzamides (3a, 3b, 3f, 4a) was studied in aqueous propylamine buffers. In the case of the aminolysis of 1a and 1b with propylamine, the rate‐limiting step consists in the decomposition of the intermediate In± catalysed by both the acidic and the basic buffer components. The base‐catalysed route is four times faster in both cases. In the case of the aminolysis of 1f with propylamine and that of 1a with ethylenediamine, the rate‐limiting step is the formation of the intermediate In±, the subsequent reaction step being accelerated by substitution and/or intramolecular catalysis. Copyright © 2005 John Wiley & Sons, Ltd.
Dipole moments of polyenic oligomeric systems. Part II—molecular organic wire resistivities: polyacetylenes, allenes and polyynes
Authors: Morales Raul G. E. , González‐Rojas Claudio
Published: April 2005

Polyacetylenic, allenic and polyynic molecular wire series, containing electron‐donor (D) and electron‐acceptor (A) groups as two terminal units of the oligomeric bridge (D–wire–A), can be well described by means of a one‐dimensional conduction model, which considers a scattering process of electrons through the charge‐transfer conduction bridge. The conduction constants (γi) of the oligomeric structures of the three molecular series under study were determined from the functional dependence between the dipole moment of the oligomers (μn) and the π‐molecular orbital bridge length (L). According to our one‐dimensional molecular organic wire model:

where μo is the dipolar moment of the first compound of the oligomeric series without a bridge unit (n = 0) and μ∞ is a limit value for L → ∞. By means of the Landauer theoretical expression for the conductance of a metallic one‐dimensional conductor and our molecular wire conduction constants (γi), we determined the intrinsic resistivities associated with the molecular resistances of these oligomeric wires. Using this approach we determined, for the first time, the linear and non‐linear contributions to the net molecular resistivity. The order of magnitudes of the linear resistivities determined in these oligomeric systems agrees very well with the expected results of experimental measurements for macroscopic wires. Copyright © 2005 John Wiley & Sons, Ltd.
End‐grafting copolymers of styrene and 4‐vinylpyridine on an interacting solid surface
Authors: Chen Zhijun , Cai Jie , Zhang Leyang , Liu Yun , Jiang Xiqun , Yang Changzheng
Published: April 2005

Copolymers of styrene and 4‐vinylpyridine with a styrene fraction f varying from 1 to 0 were grafted onto a silicon substrate in the melt. The grafting reaction and the stability of the grafted chains were investigated by Fourier transform infrared and X‐ray photoelectron spectroscopy. The thickness and surface morphology of the grafted copolymer layers were characterized with ellipsometry and atomic force microscopy (AFM). The copolymer chains were successfully grafted to the surface of the silicon substrate by a reaction between the hydroxyl groups of the nitroxide moiety at the end of the copolymers and the silanol groups on the surface of the silicon wafer. A measurement of the thickness of the grafted copolymer layers showed that the ratio of grafted‐layer thickness to the unperturbed chain radius of gyration decreased with the increasing fraction of 4‐vinylpyridine in the copolymer; this indicated that the grafted layer was strongly attracted to the substrate. In addition, an accelerated grafting process was observed at grafting times ranging from 48 to 72 h for pure poly(4‐vinylpyridine) and copolymers with f values of 0.3 and 0.5. AFM observation revealed that the grafted layers densely and homogeneously covered the silicon substrate. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 1332‐1343, 2005