bluuebunny/crossref_metadata_2025 huggingface dataset:
ChemInform Abstract: Novel Selective Biocatalytic Deacylation Studies on Key Precursors for Bicyclonucleosides
Authors: Prasad Ashok K. , Singh Sunil K. , Kalra Neerja , Singhal Nidhi , Wengel Jesper , Parmar Virinder S.
Published: March 2008

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: 2′‐Deoxy‐4′‐C‐ethynyl‐2‐fluoroadenosine: A Nucleoside Reverse Transcriptase Inhibitor with Highly Potent Activity Against Wide Spectrum of HIV‐1 Strains, Favorable Toxic Profiles, and Stability in Plasma
Authors: Ohrui Hiroshi , Kohgo Satoru , Hayakawa Hiroyuki , Kodama Eiichi , Matsuoka Masao , Nakata Tomohiro , Mitsuya Hiroaki
Published: March 2008

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Design, Synthesis, and Antitumor Activity of 4′‐Thionucleosides as Potent and Selective Agonists at the Human A3 Adenosine Receptor
Authors: Jeong Lak Shin , et al. et al.
Published: March 2008

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Design and Synthesis of Highly Potent Vitamin D Receptor Antagonists Based on the Structural Development of Vitamin D3‐26,23‐Lactone
Authors: Saito Nozomi , Kittaka Atsushi
Published: March 2008

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Synthesis of Supramolecular Boron Complexes and Their Molecular Recognition
Authors: Kameta Naohiro , Hiratani Kazuhisa
Published: March 2008

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Isoflavones—Biochemistry, Pharmacology and Therapeutic Use
Authors: Albulescu Mariana , Popovici Marinela
Published: March 2008

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Modern Methods of in situ Solid‐State NMR Spectroscopy in Heterogeneous Catalysis
Authors: Hunger Michael
Published: March 2008

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
Retrograde analyses of spinothalamic projections in the macaque monkey: Input to the ventral lateral nucleus
Authors: Craig A.D. (Bud)
Published: March 2008

The distribution of retrogradely labeled spinothalamic tract (STT) neurons was analyzed in monkeys following variously sized injections of cholera toxin subunit B (CTb) in order to determine whether different STT termination sites receive input from different sets of STT cells. This report focuses on STT input to the ventral lateral nucleus (VL), where prior anterograde tracing studies identified dense or moderately dense STT terminations. Large and very large injections in VL produced large numbers of labeled cells predominantly in laminae V and VII (more than half as many as from massive injections in the entire thalamus). Medium‐sized and small injections in VL labeled STT cells almost exclusively in laminae V and VII, in segments consistent with the coarse mediolateral VL topography; few or no cells were labeled in lamina I. All injections labeled the deep cerebellar nuclei (see accompanying article: Evrard and Craig,2008). Notably, even the most anterior injection in VL that produced dense pallidal labeling still labeled both STT and deep cerebellar cells. These observations indicate that VL receives STT input originating from laminae V and VII neurons that may be coextensive with its cerebellothalamic input. These findings support the role of laminae V and VII STT cells in sensorimotor integration and suggest a significant ongoing influence on both motor and premotor thalamocortical function. Together with the preceding observations of selective STT projections to other thalamic regions, these results provide compelling evidence that the primate STT consists of anatomically and functionally differentiable components. J. Comp. Neurol. 508:315–328, 2008. © 2008 Wiley‐Liss, Inc.
Numerical treatment of microwave guiding problems using the interfered waves model (IWM)
Authors: Elkaramany E. , El‐Hadeed F. G. A.
Published: March 2008

This paper presents a two‐dimensional frequency domain model for analyzing resonant structures. In this model, the transverse waves in the waveguide cross‐section at any point are simulated by superposition of two waves in two perpendicular directions. The relationships between the physical wave parameters and the model parameters are derived. Results for cutoff wave numbers of homogeneous arbitrarily shaped cylindrical waveguides are given to test the validity of the model. These results are compared with available analytical solutions and results given by other published methods. The model proves to give good treatment for boundary conditions and accurate results with smaller matrix size in comparison with other numerical methods. Copyright © 2008 John Wiley & Sons, Ltd.
Geometry and analysis of spin equations
Authors: Fan Huijun , Jarvis Tyler J. , Ruan Yongbin
Published: March 2008

We introduce W‐spin structures on a Riemann surface Σ and give a precise definition to the corresponding W‐spin equations for any quasi‐homogeneous polynomial W. Then we construct examples of nonzero solutions of spin equations in the presence of Ramond marked points. The main result of the paper is a compactness theorem for the moduli space of the solutions of W‐spin equations when W = W(x1, …, xt) is a nondegenerate, quasi‐homogeneous polynomial with fractional degrees (or weights) qi < ½ for all i. In particular, the compactness theorem holds for the superpotentials E6, E7, E8 or An − 1, Dn + 1 for n ≥ 3. © 2008 Wiley Periodicals, Inc.
“Could this happen to me?”: Threat‐related state orientation increases position identification with victims of random, “senseless” violence
Authors: van Zomeren Martijn , Lodewijkx Hein F. M.
Published: March 2008

Two experiments examined the role of threat‐related action‐state orientation in how observers become psychologically involved with victims of violence. Observing incidents of random, “senseless” violence is uniquely threatening to observers because they violate just world beliefs and appear like they could happen to anyone. Because stronger threat‐related state‐oriented individuals are less effective in down‐regulating such threats to the self, they should perceive stronger self‐concerned position identification (i.e., “this could happen to me”) when confronted with random, “senseless” violence. In contrast, no such effects should occur for observers' person identification (i.e., their other‐concerned empathy for the victim). The results of two experiments supported these ideas and ruled out potential alternative explanations based on individuals' just world beliefs, need for cognition, and their attribution strategies. We discuss the importance of threat‐related self‐regulation processes with regard to self‐ and other‐concerned mechanisms through which observers come to care for victims of violence. Copyright © 2008 John Wiley & Sons, Ltd.
Iron ladies, men of steel: The effects of gender stereotyping on the perception of male and female candidates are moderated by prototypicality
Authors: Lammers Joris , Gordijn Ernestine H. , Otten Sabine
Published: March 2008

Women remain a minority in politics. In nearly all countries, including parliamentary democracies, women are still underrepresented in national parliament and other representative institutions. Research has argued that there is a bias against women in elections. Here we study the process behind this phenomenon by investigating the effect of a candidate's gender and gender prototypicality on judgment of the suitability of this candidate in elections. The first experiment shows that when voters think topics that stereotypically demand male characteristics (e.g., competitiveness) are important, they prefer male candidates, while they prefer female candidates when topics that stereotypically demand female characteristics (e.g., pro‐sociability) are important. Experiment 2 replicates this and shows that this effect is fully reversed for counterprototypical (i.e., in physical appearance) candidates. This supports a stereotyping as prediction account, and has important theoretical and practical implications. Copyright © 2008 John Wiley & Sons, Ltd.
Enhancement of power system performance by LFC analysis of hydro power plants using QFT
Authors: Khodabakhshian A.
Published: March 2008

The paper presents a unified approach for the design of the decentralized PID load frequency controller, based on the Quantitative Feedback Theory (QFT). This method not only handles the parametric uncertainty in power systems, but also covers a wide range of load changes. The proposed controller design is simple and effective. The digital simulation results on a multimachine power system example with different operating conditions show that the performance of the controller is robust and effectively improves the dynamical stability of power system. Copyright © 2008 John Wiley & Sons, Ltd.
A circuit based method for multiarea transmission networks loss allocation
Authors: Kazemi Ahad , Jadid Shahram , Andami Hooman
Published: March 2008

This paper deals with the problem of transmission loss allocation in very large networks with multiple interconnected regions or countries. The main objective is to propose a method in order to identify the amount of losses that each participant in the market causes on all system areas. Transmission pricing of cross‐border trades is often difficult since individual countries may use incompatible internal transmission pricing regimes, and they are usually unwilling to disclose any sensitive information about their own systems.

This paper presents a new methodology based on the loss formula concept for allocating electric losses to generators and loads, participating in multiple interconnected energy markets. The only data required are the power flows and characteristics of tie‐lines and PV Ward equivalent model of area networks from border nodes point of view. No information is required about individual loads, generations, or detailed internal networks. The methodology is illustrated on the IEEE 118 node network which is divided into three areas, each with a different internal transmission pricing methodology. The proposed methodology is shown to be simple, transparent and very fast, and it can deal effectively with multiple pricing regimes. Copyright © 2008 John Wiley & Sons, Ltd.
Temperature distribution in ONAN power transformer windings with finite element method
Authors: Taghikhani M. A. , Gholami A.
Published: March 2008

Since large power transformers belong to the most valuable assets in electrical power networks, it is suitable to pay higher attention to these operating resources. Thermal impact leads not only to long‐term oil/paper‐insulation degradation; it is also a limiting factor for the transformer operation. Therefore, the knowledge of the temperature, especially the hot‐spot temperature (HST), is of high interest. The calculation of current thermal stress helps to avoid unexpected outages. This paper presents the temperature distribution in windings of the oil power transformers. In this paper, energy (thermal) equation is solved until temperature is obtained. Oil in the transformer is assumed nearly incompressible and oil parameters such as thermal conductivity, special heat, viscosity, and density vary with temperature. For numerical solution of above equation, finite element method is used. The selected models for simulation are 300 KVA and 22.5 MVA ONAN transformers. Copyright © 2008 John Wiley & Sons, Ltd.
Lifestyle regularity and cyclothymic symptomatology
Authors: Shen Gail H. C. , Sylvia Louisa G. , Alloy Lauren B. , Barrett Fred , Kohner Melissa , Iacoviello Brian , Mills Ana
Published: March 2008

The social zeitgeber theory emphasizes the importance that social rhythm regularity may play in promoting internal synchronization of circadian rhythms in individuals with or at risk for bipolar spectrum disorders. This study examined the relationship of lifestyle regularity, affective symptomatology, and sleep in 71 individuals exhibiting cyclothymic mood and behavior patterns. Participants were randomly assigned to either an experimental group in which they were encouraged to regulate their daily routines or to a control group. Participants in the experimental group were able to successfully regulate their daily schedules. Although relationships between regularity and severity of depressive symptoms, across‐day variances in mood and behavior, and sleep duration were identified during baseline, increased lifestyle regularity did not differentially result in changes in these variables. © 2008 Wiley Periodicals, Inc. J Clin Psychol 64: 1–19, 2008.
Atmospheric moisture budget over Antarctica and the Southern Ocean based on the ERA‐40 reanalysis
Authors: Tietäväinen Hanna , Vihma Timo
Published: March 2008

The atmospheric moisture budget over Antarctica and the Southern Ocean was analysed for the period 1979–2001 on the basis of the ERA‐40 reanalysis of the European Centre for Medium‐Range Weather Forecasts. Meridional transport by transient eddies makes the largest contribution to the southward water vapour transport. The mean meridional circulation contributes to the northward transport in the Antarctic coastal areas, but this effect is compensated by the southward transport by stationary eddies. The convergence of meridional water vapour transport is at its largest at 64–68°S, while the convergence of zonal transport is regionally important in areas of high cyclolysis. Inter‐annual variations in water vapour transport are related to the southern annular mode (SAM). The eastward transport has a significant (95% confidence level) positive correlation with the SAM index, while the northward transport has a significant negative correlation with SAM near 60°S. Hydrological balance is well‐achieved in the ERA‐40 reanalysis: the difference between the water vapour flux convergence (based on analysis) and the net precipitation (precipitation minus evaporation, based on 24‐h forecasts) is only 13 mm yr−1 (3%) over the Southern Ocean and − 8 mm yr−1 (5%) over the continental ice sheet. Over the open ocean, the analysis methodology favours the accuracy of the flux convergence. For the whole study region, the annual mean flux convergence exceeded net precipitation by 11 mm yr−1 (3%). The ERA‐40 result for the mean precipitation over the Antarctic continental ice sheet in 1979–2001 is 177 ± 8 mm yr−1, while previous estimates range from 173 to 215 mm yr−1. For the period 1979–2001, the ERA‐40 data do not show any statistically significant trend in precipitation over the Antarctic grounded ice sheet and ice shelves. From the ERA‐40 data, the annual average net evaporation (evaporation minus condensation) is positive over the whole continent. Copyright © 2008 Royal Meteorological Society
Enhanced OCT imaging of embryonic tissue with optical clearing
Authors: Larina I V , Carbajal E F , Tuchin V V , Dickinson M E , Larin K V
Published: March 2008

Optical coherence tomography (OCT) holds great promise as a routine research tool for 3-D analysis of mammalian embryos. However, despite the depth penetration afforded by this imaging modality, light attenuation in tissues imposes limitations. Here we studied the optical clearing effect of different concentrations of glycerol in mouse embryos. Depth- and time-resolved profiles for OCT signal enhancement are presented. We found that application of 50% glycerol resulted in 51.5±12.5% improvement of the OCT signal, while 25% glycerol enhanced the OCT signal by 25.2±7.3% at the depth of about 200 to 500 μm, and the glycerol permeability rate was estimated as 26.7±6 μm/min. These results demonstrate that embryonic imaging is improved by application of glycerol as optical clearing agent.
Characterizing Biodegradation of PLA and PLA‐g‐AA/Starch Films Using a Phosphate‐Solubilizing Bacillus Species
Authors: Wu Chin‐San
Published: March 2008

The use of PLA and PLA‐g‐AA/starch as materials for the controlled release of encapsulated PSB was evaluated. The results showed that the bacterium degraded both the PLA and the PLA‐g‐AA/starch composite films, resulting in cell release. Severe disruption of the film structure occurred after incubation for 60–90 d. The PLA‐g‐AA/starch (20 wt.‐%) films were more biodegradable than those made of PLA and also suffered a more pronounced decrease in molecular weight and intrinsic viscosity. Although blending of starch appeared to enhance the biodegradability of the PLA films, the pattern of degradation was quite similar for both types of films. The rate of cell release depends on the biodegradability of the film.

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In Situ Mineralization of Hydroxyapatite on Electrospun Chitosan‐Based Nanofibrous Scaffolds
Authors: Yang Dongzhi , Jin Yu , Zhou Yingshan , Ma Guiping , Chen Xiangmei , Lu Fengmin , Nie Jun
Published: March 2008

A biocomposite of hydroxyapatite (HAp) with electrospun nanofibrous scaffolds was prepared by using chitosan/polyvinyl alcohol (CS/PVA) and N‐carboxyethyl chitosan/PVA (CECS/PVA) electrospun membranes as organic matrix, and HAp was formed in supersaturated CaCl2 and KH2PO4 solution. The influences of carboxylic acid groups in CECS/PVA fibrous scaffold and polyanionic additive poly(acrylic acid) (PAA) in the incubation solution on the crystal distribution of the HAp were investigated. Field‐emission scanning electron microscopy (FE‐SEM), energy‐dispersive spectroscopy (EDS), wide‐angle X‐ray diffraction (WAXD), and Fourier transform infrared (FTIR) were used to characterize the morphology and structure of the deposited mineral phase on the scaffolds. It was found that addition of PAA to the mineral solution and use of matrix with carboxylic acid groups promoted mineral growth and distribution of HAp. MTT testing and SEM imaging from mouse fibroblast (L929) cell culture revealed the attachment and growth of mouse fibroblast on the surface of biocomposite scaffold, and that the cell morphology and viability were satisfactory for the composite to be used in bioapplications.

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Separation of Parent Homopolymers from Diblock Copolymers by Liquid Chromatography under Limiting Conditions Desorption, 1 ‐ Principle of the Method
Authors: Berek Dušan
Published: March 2008

A novel group of liquid chromatographic methods was developed, namely liquid chromatography under limiting conditions of enthalpic interactions (LC LC). LC LC utilizes the difference in the elution rates of the slow, pore permeating small solvent molecules and the fast traveling pore excluded macromolecules. The appropriately chosen small molecules create a barrier, which selectively promotes enthalpic interactions of one kind of polymer chains within the chromatographic system and thus blocks their fast elution. The non‐interacting polymer chains elute rapidly. Two different barriers enable simultaneous separation of both parent homopolymers from a diblock copolymer.

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Mesoscopic Patterning in Evaporated Polymer Solutions: Poly(ethylene glycol) and Room‐Temperature‐Vulcanized Polyorganosilanes/‐siloxanes Promote Formation of Honeycomb Structures
Authors: Bormashenko Edward , Malkin Alexander , Musin Albina , Bormashenko Yelena , Whyman Gene , Litvak Natalya , Barkay Zahava , Machavariani Vladimir
Published: March 2008

Patterning in evaporated polymer solutions based on amorphous polymers and chlorinated solvents has been investigated. Bilayered films patterned on two scales, i.e., 50 and 5 µm, are obtained. The addition of polyorganosilane/‐siloxane to solutions destroys the large‐scale pattern. Poly(ethylene glycol) promotes the formation of more dense close‐packed structures on the mesoscopic scale (≈5 µm). Short‐range and mesoscopic (liquid‐like) ordering of the honeycomb structures on the characteristic scale of 5 µm is revealed with the statistical analysis of SEM images. Physical mechanisms responsible for patterning are discussed.

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Controlled/“Living” Radical Polymerization of Methyl Methacrylate Catalyzed by Cobalt Acetate
Authors: Huang Zhong‐Xi , Zhang Yong‐Ming , Li Hong , Liu Yan‐Gang
Published: March 2008

Using cobalt acetate as a catalyst, the controlled/“living” polymerization of MMA was carried out. PMMA with a predicted molecular weight and a low polydispersity $(\overline M _{\rm w} /\overline M _{\rm n} = 1.26)$ was obtained. Using the obtained PMMA as a macroinitiator, a chain extension reaction was carried out. This increased the molecular weight of PMMA from 23 600 to 36 100, in good agreement with the predicted value, and the polydispersity index became lower $(\overline M _{\rm w} /\overline M _{\rm n} = 1.22)$. This indicated the “living” character of the polymerization. Bulk polymerization of styrene catalyzed by cobalt acetate using the obtained polystyrene as a macroinitiator yielded well‐defined PS‐b‐PMMA.

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Facile Preparation of Branched Phosphazene‐Containing Nanotubes via an in situ Template Approach
Authors: Fu Jianwei , Huang Xiaobin , Huang Yawen , Zhu Lu , Zhu Yan , Tang Xiaozhen
Published: March 2008

Based on an in situ template method, branched phosphazene‐containing nanotubes were synthesized via a controlled two‐step adding technique of acid acceptors. Structural and morphological characterizations of the as‐synthesized products were performed by SEM, TEM, EDX and FTIR. The results showed that the branched nanotubes were had inner and outer diameters of 8 and 50–150 nm, respectively. In addition, a formation mechanism for the nanostructures was proposed.

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Influence of Interfacial Properties on Crack Propagation in Fiber‐Reinforced Polymer Matrix Composites
Authors: Sun Lili , Jia Yuxi , Ma Fengde , Zhao Jiang , Han Charles C.
Published: March 2008

Dynamic crack propagation routes in composites were investigated using numerical methods. The interfacial strength was characterized by means of the interfacial nodal constrained failure. Five different micro‐damage modes around a broken fiber and the corresponding stress/strain curves were obtained with the interfacial strength increasing. It was proved that the shear stress concentration region appears to be different as the interface varying from weak to strong and that the recovery of fiber load‐supporting with a strong interface is better than that with a weak interface. Experimental work has been done and the available results agree well with corresponding simulation results.

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Exploring Actuation and Mechanotransduction Properties of Polymer Brushes
Authors: Comrie Jean E. , Huck Wilhelm T. S.
Published: March 2008

Soft nanotechnology requires new approaches and materials to efficiently convert chemical energy into mechanical motion and vice versa. A number of key design parameters, such as responsiveness to external stimuli, directionality of response through alignment, transduction via surface stresses or changes in ionic conductivity can be found in polymer brushes and several recent examples of actuation and transduction in polymer brushes will be explored.

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Macromol. Rapid Commun. 5/2008
Authors: Gin Douglas L. , Bara Jason E. , Noble Richard D. , Elliott Brian J.
Published: March 2008

Cover: The cover picture shows how cross‐linked polymers containing uniform, aqueous pores with diameters of ≤1.2 nm can be made by the radical photopolymerization of self‐organized lyotropic liquid crystal (LLC) (i.e., surfactant) monomer assemblies. Depending on the shape of the LLC monomers and their packing preferences, cross‐linked networks with ordered 1‐D cylindrical or 3‐D interconnected pore systems can be generated. The resulting nanostructured polymer films are able to perform enhanced gas and liquid separations via control of the solubility‐diffusivity characteristics of the substrate molecules passing through them, or via molecular size‐exclusion through the nanopores. Further details can be found in the article by D. L. Gin,* J. E. Bara, R. D. Noble, and B. J. Elliott on page 367.
Comparative analysis of hydrogen bonding with participation of the nitrogen, oxygen and sulfur atoms in the 2(2′‐heteroaryl)pyrroles and their trifluoroacetyl derivatives based on the 1H, 13C, 15N spectroscopy and DFT calculations
Authors: Afonin Andrei V. , Vashchenko Alexander V. , Ushakov Igor A. , Zorina Nadezhda V. , Schmidt Elena Yu.
Published: March 2008

The NHċbondX (X = N,O,S) intramolecular hydrogen bond in the series of 2(2′‐heteroaryl)pyrroles and their trifluoroacetyl derivatives is examined by the 1H, 13C, 15N spectroscopy and density functional theory (DFT) calculations. The influence of the hydrogen bond on coupling and shielding constants is considered. It is shown that the NHċbondN intramolecular hydrogen bond causes a larger increase in the absolute size of the 1J(N,H) coupling constant and a larger deshielding of the bridge proton than the NHċbondO hydrogen bond. The effect of the NHċbondS interaction on the 1J(N,H) coupling constant and the shielding of the bridge proton is small. The NMR parameter changes in the series of the 2(2′‐heteroaryl)pyrroles due to NHċbondX hydrogen bond and the series of the 1‐vinyl‐2‐(2′‐heteroaryl)‐pyrroles due to CHċbondX hydrogen bond have the same order. The proximity of the nitrogen, oxygen or sulfur lone pair to the FċbondH hydrogen bridge quenches the trans‐hydrogen bond spin–spin couplings 1hJ(F,H‐1) and 2hJ(F,N). Copyright © 2008 John Wiley & Sons, Ltd.
Diastereomeric difference of inclusion modes between (−)‐epicatechin gallate, (−)‐epigallocatechin gallate and (+)‐gallocatechin gallate, with β‐cyclodextrin in aqueous solvent
Authors: Ishizu Takashi , Kajitani Shinya , Tsutsumi Hiroyuki , Yamamoto Hideji , Harano Kazunobu
Published: March 2008

Inclusion complexes of (−)‐epicatechin gallate (ECg) as well as (+)‐gallocatechin gallate (GCg) and β‐cyclodextrin (β‐CD) in an aqueous solution were investigated using several NMR techniques and a computational method. ECg and EGCg formed a 1:1 complex with β‐CD, in which the A ring and a portion of the C ring were included from the wide secondary hydroxyl group side of the β‐CD cavity, and the B and B′ rings were left outside the cavity. GCg formed a 1:2 complex with β‐CD, in which the A and B rings of GCg were included by two molecules of β‐CD. The difference between the two modes of inclusion of the 1:1 complex of ECg, EGCg·β‐CD and the 1:2 complex of GCg·β‐CD might have resulted from the size of the space between the B and B′ rings in aqueous solution. As a result of nueclear Overhauser effect (NOE) experiments, GCg was considered to have a large enough space between the B and B′ rings to include the B ring in the β‐CD cavity; on the other hand, ECg and EGCg have no such large space. Copyright © 2008 John Wiley & Sons, Ltd.
Copolymerization of 2‐Acrylamido‐2‐methyl‐1‐propanesulfonic Acid and 1‐Vinylimidazole in Inverse Miniemulsion
Authors: Wiechers Susann , Schmidt‐Naake Gudrun
Published: March 2008

The copolymerization behavior of the acidic monomer 2‐acrylamido‐2‐methyl‐1‐propanesulfonic acid (APSA) and 1‐vinylimidazole in inverse miniemulsion was studied under various conditions. Initially, different surfactants and surfactant concentrations were investigated. After determining a suitable composition of the miniemulsion, changes in the reaction behavior under different pH values and monomer feed compositions were studied. The highest polymerization rates could be produced under neutral conditions over all monomer feed ratios. The addition of acid or base to change the pH value of the monomer mixture also has influence on the polymers obtained. The thermal stability, rheological stiffness and intrinsic viscosity increase when Na‐APSA is incorporated.

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Chain Length Distributions of Polyolefins Made in Stopped‐Flow Reactors for Non‐Instantaneous Site Activation
Authors: Soares João B. P. , Hamielec A. E.
Published: March 2008

We developed an analytical solution to describe how the chain length distribution (CLD) of polymers made with coordination polymerization catalysts vary as a function of time for very short polymerizations considering non‐instantaneous site activation. This solution is an extension of our previous analytical expression for instantaneous site activation. We validated the analytical solution with dynamic Monte Carlo simulation and obtained excellent agreement. Simulation results indicate that, unless the catalyst activation rate is much lower than the propagation rate, it will have only a minor effect on the initial shape of the CLD of polymers made in stopped‐flow reactors (SFR). We also show how incorrect polymerization kinetic parameters may be estimated when assuming instantaneous site activation when this hypothesis is not applicable to the polymerization data under investigation.

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Continuous Soluble Ziegler‐Natta Ethylene Polymerizations in Reactor Trains, 2 – Estimation of Kinetic Parameters from Industrial Data
Authors: Embiruçu Marcelo , Prata Diego Martinez , Lima Enrique Luis , Pinto José Carlos
Published: March 2008

We show that it is possible to estimate kinetic parameters for complex mechanistic polymerization models from available industrial data. A methodology is developed for efficient handling and reconciliation of industrial data and is then applied to allow estimation of kinetic parameters for industrial ethylene polymerizations performed in reactor trains using soluble Ziegler‐Natta catalysts. The parameter estimation procedure is formulated as a nonlinear optimization procedure subject to hard and soft model and process constraints. Parameter estimates obtained for the catalyst system allow a very good description of actual industrial data used during the estimation process and also allow very good prediction of process performance when completely new operating conditions are considered. It is concluded that complex phenomenological models can be successfully fitted to actual industrial processes without the need to carry out extensive experimental tests in the laboratory.

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Continuous Soluble Ziegler‐Natta Ethylene Polymerizations in Reactor Trains, 3 – Influence of Operating Conditions upon Process Performance
Authors: Embiruçu Marcelo , Pontes Karen , Lima Enrique Luis , Pinto José Carlos
Published: March 2008

The behavior of continuous solution ethylene/but‐1‐ene polymerizations through Ziegler‐Natta catalysts is analyzed, based on a previously developed mathematical model. In order to do that, dynamic simulations are carried out and process responses are analyzed as functions of process operating policies and flowsheet configuration, at conditions that resemble the actual operation of industrial sites. It is shown that system responses are highly nonlinear and very sensitive to disturbances of the operating conditions and that catalyst decay is of fundamental importance for proper understanding of process behavior. Results indicate that mixing conditions inside the reactor vessels exert a significant impact upon the final polymer quality and can be manipulated for in‐line control of final resin properties. Finally, it is shown that the development of feed policies, based on the use of lateral feed streams, allows the simultaneous control of melt flow index, stress exponent and polymer density of the final polymer resin.

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Critical branching processes in neural networks
Authors: Levina Anna , Herrmann J. Michael , Denker Manfred
Published: March 2008

Self‐organized criticality generates complex behavior in systems of simple elements. It is observed in various biological neural systems and has been analyzed in simplified model systems. Branching processes often considered to be a mean‐field approximation to the dynamics of critical systems. Here we study the validity of such an approximation for the case of a neural network. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Coupled nonlinear effects in modeling field emission from CNTs
Authors: Melnik R.V.N. , Mahapatra D. Roy , Sinha N. , Yeow J.T.W.
Published: March 2008

Field emission from carbon nanotubes (CNTs) is a complex process involving a range of physical effects and phenomena. In this paper, we systematically develop a multiphysics model to describe this process. We integrate the model numerically to estimate the output current from a CNT based field emission device. Numerical simulations have been able to capture the transients in current as observed in actual experiments. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Interior point methods for linear complementarity problems
Authors: Potra Florian A.
Published: March 2008

A short survey of interior point methods for linear complementarity problems with emphasis on algorithms that have both polynomial complexity and superlinear convergence is presented. Some recent results obtained by the author and his collaborators are briefly summarized and several directions of future research are proposed. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Optimal control of robots under stochastic uncertainty: robust feedback control
Authors: Schacher Michael
Published: March 2008

The most important aspect in the optimal control and design of manipulators is the determination of the basic movement, i.e. the calculation of the optimal trajectory on which the robot has to move. Having an optimal reference trajectory and an optimal open‐loop control, there is the need of control corrections by applying a certain feedback control. Different attempts exist for this.

In this article a method will be shown which is based on classical control theory, that works with cost functions being minimized. The aim is to take into account stochastic parameter variations in order to obtain robust optimal feedback controls. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Applications of homogenization techniques to the electrical conduction in biological tissues
Authors: Amar Micol , Andreucci Daniele , Bisegna Paolo , Gianni Roberto
Published: March 2008

We study a family of problems set in a finely mixed periodic medium, modelling electrical conduction in biological tissues. We prove a unified derivation of these different schemes from the Maxwell equations in the quasi‐stationary approximation and we investigate the behaviour of the corresponding macroscopic models. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Surface integral methods for high‐frequency electromagnetic scattering
Authors: Ganesh M. , Hawkins S. C.
Published: March 2008

Surface integral equation based methods are advantageous for simulation of electromagnetic waves scattered by three dimensional obstacles, because they efficiently reduce the dimension of the problem and are robust for high‐frequency problems. However, the cost of setting up the associated discretized dense linear systems is prohibitive due to evaluation of highly oscillatory magnetic and electric dipole surface integral operators using standard cubatures. The computational complexity of evaluating such integrals depends on the incident wave frequency, and the size and shape of the obstacles. In this work we discuss a surface integral reformulation of the scattering problem that involves evaluation of surface integrals with a highly oscillatory physical density, and discuss methods for efficient evaluation of such integrals for a class of smooth three dimensional scatterers whose diameter is a large multiple of the incident wavelength. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
On wear pattern generation in elastic systems
Authors: Hoffmann Norbert
Published: March 2008

In systems with moving contacts spatially periodic wear patterns may appear on the contact partners surfaces. There is agreement that the patterns are related to structural resonances. Using a simple model with a moving point contact and an idealized wear model the present work reviews some of the present understanding of wear‐pattern generation. Then the effect of randomly specified relative velocities on the wavelength selection process is investigated. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Evaluating drug toxicity signals: is a hierarchical classification of evidence useful or a hindrance?
Authors: van Staa T. P. , Smeeth L. , Persson I. , Parkinson J. , Leufkens H. G. M.
Published: March 2008

Purpose

Only randomized clinical trials (RCTs) are deemed suitable to determine causality, as epidemiological studies are considered not ‘robust’. The objective of this study was to evaluate whether causality should remain the only consideration with drug toxicity signals. Cyclooxygenase‐2 (Cox‐2) inhibitors provided an example.

Methods

Our study population included patients aged 40+ years prescribed Cox‐2 inhibitors in the General Practice Research Database (GPRD) (N = 150 000). We estimated the risks of upper gastrointestinal (GI) events and myocardial infarction (MI). Attributable risks were estimated using simulation methodology based on various hypothetical scenarios.

Results

The risk–benefit profile was strongly related to the rate of GI events. With a RCT incidence, the GI benefits would exceed MI risks. With a ‘real‐life’ GI incidence, the benefits did not exceed the risks substantially. The onset and offset of drug effects also predicted the magnitude of both risks and benefits. If risks and benefits occurred in different sub‐groups, the risk–benefit profile varied substantially. Also, it was found that any restriction of use to patients at high risk of drug toxicity may not improve the risk–benefit profile when this restriction affected patients who would benefit most.

Conclusions

We conclude that rigid classification of evidence is not appropriate in the monitoring of risks and benefits and all valid study evidence—not only that derived from a RCT— needs to be included. The first priority should be to consider the potential impact of a drug toxicity signal. Copyright © 2008 John Wiley & Sons, Ltd.
Current Distribution on the Substrate in a Vacuum Arc Deposition Setup
Authors: Baranov Oleg , Romanov Maxim
Published: March 2008

The effect of a magnetic field generated by a planar magnetron on the ion current distribution on the substrate has been investigated as a function of the substrate voltage and gas pressure for two configurations of the magnetic field. The probe and the substrate were biased by negative potentials of −60 to −280 V with respect to the grounded anode, in order to collect the saturated ion current and investigate the influence of the magnetron magnetic field on the distribution of the ion flux of the vacuum arc source. It was shown that the planar magnetron placed under the substrate strongly affects the ion current and ion current distribution near the substrate. For a broad pressure range, the maximum ion flux collected by the probe increased by 40%, while the net ion current to the substrate increased by 20%. We have demonstrated that the ion current increased by 18%, and maximum ion current density increased by 40%. The results were explained in terms of the plasma flux interaction with the magnetic field of the magnetron. The setup may be suitable for controlling ion flux density on large substrates.

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Mechanical and thermal behaviour of flexible food packaging polymeric films materials under high pressure/temperature treatments
Authors: Galotto M J , Ulloa P.A , Hernández D. , Fernández‐Martín F. , Gavara R. , Guarda A.
Published: March 2008

The effect of high‐pressure processing on mechanical and thermal properties of four complex packaging materials (polyethylene/ethylene vinyl alcohol/ polyethylene: PE/EVOH/PE; metallized polyester/polyethylene: PETmet/PE; polyester/polyethylene: PET/PE; polypropylene SiOx recovered: PPSiOx) was studied. Pouches of the different materials containing distilled water or olive oil as food simulants, as well as empty ones, were subjected to 400  MPa for 30  min, at temperatures of 20 or 60°C. Delamination and wrinkling were a general consequence of the high‐pressure processing of multilayer polymeric systems. However, no significant changes were observed regarding the mechanical properties of PE containing laminates after pressurization. PPSiOx underwent significant modifications as SiOx completely broke down. Neither thermal property was affected by pressure, as it was the processing temperature that induced tempering effects on the crystallization behaviour of polymeric components. Only PE/EVOH/PE, when in contact with water as a simulant, presented a decrease in the melting point temperature. Copyright © 2008 John Wiley & Sons, Ltd.
Validation of a mixed‐layer closure. II: Observational tests
Authors: Lilly Douglas K.
Published: March 2008

Data from the DYCOMS2 observational campaign are used to test a mixed‐layer entrainment model presented previously by the author. The model is extended to include the effects of drizzle precipitation and radiative warming from the surface. The most consistent results are obtained under the assumption that the mixed‐layer top is unsaturated, that is, the cloud top is below the top of the turbulent flow. With this assumption, the predicted entrainment rates lie near those obtained by Faloona et al., and are well correlated with them, but are sensitive to the evaluation of temperature and moisture jumps and other parameters. The predicted entrainment rates are substantially smaller than those observed by Gerber et al., and are not correlated with them.

Drizzle precipitation, as evaluated by VanZanten et al., reduces entrainment rates due to evaporative cooling below cloud base. This effect appears to improve the comparisons with observations. Tests of the robustness of the model calculations show mostly encouraging results. The effect of surface radiation into cloud base is found to be almost negligible. A new criterion for cloud‐top entrainment instability, based on the entrainment closure, indicates stability for most observed conditions. The homogeneity of the DYCOMS2 data is beneficial for obtaining reliable measures of entrainment, but limits the ability to test closure predictions over a wide range of conditions.

Use of this model for parametrization of marine stratiform cloud layers in large‐scale or climate prediction models is considered plausible with limitations. Copyright © 2008 Royal Meteorological Society
Validation of a mixed‐layer closure. I: theoretical tests
Authors: Lilly Douglas K. , Stevens Bjorn
Published: March 2008

A flux closure formula introduced earlier for predicting entrainment into a mixed layer is tested through analytic solution of the kinetic energy equation and through large‐eddy simulation. For this purpose, the closure formulation and the simulation model are applied to the ‘smoke cloud’ mixed layer, that includes both radiative cooling at the cloud top and surface heating or cooling at the surface, but without the effects of latent heat. The unique aspect of the closure, height weighting of the integral of buoyancy flux, is found to be directly related to the ratio of coefficients of the dissipation and diffusion terms of the energy equation.

The simulation results indicate that the previous expression for predicting the entrainment flux is about 10% too small. Results of analytic solutions of the energy equation and the simulations are in general agreement. Disagreements are believed to be due to approximations in the energy equation and possible imperfections in the simulation model.

A special issue investigated is the condition for decoupling of energy by surface radiative cooling. The maximum negative buoyancy flux before decoupling predicted by the flux closure and by the energy equation differ by almost a factor of 2, but it is not clear which is better. Copyright © 2008 Royal Meteorological Society
A numerical study of three catastrophic precipitating events over southern France. I: Numerical framework and synoptic ingredients
Authors: Nuissier O. , Ducrocq V. , Ricard D. , Lebeaupin C. , Anquetin S.
Published: March 2008

This study examines the simulation of three torrential rain events observed on 13–14 October 1995 (the Cévennes case), 12–13 November 1999 (the Aude case) and 8–9 September 2002 (the Gard case) over the southeastern part of France using the Meso‐NH non‐hydrostatic mesoscale numerical model. These cases were associated with extreme Heavy Precipitation Events (HPEs) with significant precipitation amounts exceeding 500 mm in less than 24 hours. Several sets of numerical experiments were performed with 10 km and 2.5 km horizontal resolutions. In part I of this study, special attention is paid to the experimental design for obtaining realistic simulations of HPEs with the Meso‐NH model, as well as the evolution of the synoptic patterns in which the rainfall events are embedded.

The best 2.5 km numerical simulations show the ability of the Meso‐NH model to reproduce significant quasi‐stationary rainfall events. Moreover, the model fairly reproduces the low‐level mesoscale environments associated with the three HPEs. The HPEs formed in a slow‐evolving synoptic environment favourable for the development of convective systems (diffluent upper‐level southerly flow, PV anomalies, etc.). At lower levels, a southerly to easterly moderate to intense flow provided conditionally unstable and moist air as it moved over the relatively warm Mediterranean Sea, typical for this time of the year (late summer and autumn). The two extreme cases (Gard and Aude) differ from the more classical event (Cévennes) in terms of larger low‐level moisture fluxes. Weaker values of conditional convective instability, as in the Aude case, is counterbalanced by a stronger warm and moist low‐level jet. The mesoscale triggering and/or sustaining ingredients for deep convection and the physical mechanisms leading to the stationarity of these rainfall events are presented and discussed in a companion paper. Copyright © 2008 Royal Meteorological Society