bluuebunny/crossref_metadata_2025 huggingface dataset:
Oxidized States of Methoxy-sexithiophene Derivative with Ferrocenyl Groups
Authors: Sato Masa-aki , Fukui Kazuhiko
Published: June 2006

Methoxy-sexithiophene derivative with two ferrocenyl terminal groups was prepared as a model compound for molecular wires. The oxidation process and the oxidized states of the model compound were investigated by cyclic voltammetry, coulometry, and electronic absorption spectroscopy. The first oxidation occurs in a ferrocene moiety, terminal, and the resultant oxidized species strongly interacts not only with the methoxy-sexithiophene moiety, but also with the other ferrocene.
Synthesis and Kaleidoscopic Reactivities of Bis(tritolylgermyl)bis(dimethylphenylphosphine)platinum(II)
Authors: Usui Yoko , Fukushima Takashi , Nanjo Masato , Mochida Kunio , Akasaka Kuniyoshi , Kudo Takako , Komiya Sanshiro
Published: June 2006

A series of tritolylgermylplatinum complexes Pt(GeAr3)2(PMe2Ph)2 (Ar = o-tol, m-tol, and p-tol) were prepared and kaleidoscopic reactivities were observed by only changing the substituents at the germyl tolyl groups: (1) cis–trans isomerization at platinum, (2) C–H bond activation of ortho methyl group, and (3) reductive elimination at Pt giving Ge–Ge bond.
Biotechnology and the WTO: A Review of some Selective Issues
Authors: Horng Der-Chin
Published: June 2006

Biotechnology and the WTO have increasingly intersected following the growth of biotech trade. The regulatory challenge of biotechnology is a current subject of debate in the WTO. Biotechnology highlights emerging tensions between the effectiveness of the WTO law on biotech issues and the public health and the non-trade issues of biotech trade. Based on legal analysis, this paper reviews the policy issues caused by biotechnology and its implications on the organization and also considers the kind of policy options needed to achieve an appropriate balance between biotech interests and WTO discipline.
Raumverhalten auf dem Papier: Der Untergang eines komplexen Zeichensystems dargestellt an Briefstellern des 19. und des 20. Jahrhunderts
Authors: Ehlers Klaas-Hinrich
Published: June 2006

In the 19
Tagungsbericht zur 4. Tagung deutschsprachiger Akademiewörterbücher vom 9.–12. September 2003 in Göttingen
Authors: Katzmann Andrea
Published: June 2006

Vom 9. bis zum 12. September 2003 fand in Göttingen die
Patterns of Nucleotide Polymorphism Distinguish Temperate and Tropical Wild Isolates of Caenorhabditis briggsae
Authors: Cutter Asher D , Félix Marie-Anne , Barrière Antoine , Charlesworth Deborah
Published: June 2006

Caenorhabditis briggsae provides a natural comparison species for the model nematode C. elegans, given their similar morphology, life history, and hermaphroditic mode of reproduction. Despite C. briggsae boasting a published genome sequence and establishing Caenorhabditis as a model genus for genetics and development, little is known about genetic variation across the geographic range of this species. In this study, we greatly expand the collection of natural isolates and characterize patterns of nucleotide variation for six loci in 63 strains from three continents. The pattern of polymorphisms reveals differentiation between C. briggsae strains found in temperate localities in the northern hemisphere from those sampled near the Tropic of Cancer, with diversity within the tropical region comparable to what is found for C. elegans in Europe. As in C. elegans, linkage disequilibrium is pervasive, although recombination is evident among some variant sites, indicating that outcrossing has occurred at a low rate in the history of the sample. In contrast to C. elegans, temperate regions harbor extremely little variation, perhaps reflecting colonization and recent expansion of C. briggsae into northern latitudes. We discuss these findings in relation to their implications for selection, demographic history, and the persistence of self-fertilization.
Camptothecin induces the transit of FasL trimers to the cell surface in apoptotic HEp-2 cells
Authors: Meza-Lamas Esteban , Bollain-Y-Goytia Juan-José , Ramírez-Sandoval Roxana , Sánchez-Rodríguez Sergio , López-Robles Erendira , Avalos-Díaz Esperanza , Herrera-Esparza Rafael
Published: June 2006

Fas ligand (L) is a membrane protein from the tumor necrosis factor (TNF) family. It induces apoptosis upon contact with its Fas/CD95/APO1 receptor. Trimerization of FasL on the surface of effector cells is essential in the binding of the Fas trimer of the target cells. The receptor then recruits an adaptor and caspase-like proteins which lead apoptosis. This paper reports on the fate of FasL in HEp-2 cells committed to apoptosis by induction with campthotecin. Our main results demonstrated that in non-apoptotic cells, FasL aggregates in the cytoplasm forming trimers of 120 kDa. Apoptosis increases the trimeric FasL species, but also induces its dissociation into monomers of 35 kDa. In conclusion, camptothecin appears to perturb the Fas and FasL segregation in the cytoplasm by promoting the transit of FasL to the cell surface, thus fostering a process of autocrine or paracrine apoptosis. FasL is trimerized prior to Fas/FasL complex formation, and after apoptosis, FasL undergoes an intense turnover.
Water‐induced rearrangement of Ca(OH)2 (0001) surfaces reacted with SO2
Authors: Bausach M. , Pera‐Titus M. , Fite C. , Cunill F. , Izquierdo J.‐F. , Tejero J. , Iborra M.
Published: June 2006

AFM imaging and EDS microanalyses provide evidence of the reorganization of single‐crystal Ca(OH)2 (0001) surfaces attacked by SO2 at low temperature when exposed to water vapor in such a way that larger product features are formed from the aggregation of smaller ones. This product rearrangement induced by water vapor might provide a new accessible Ca(OH)2 surface for further reaction with SO2, which might account for the general observation reported in the literature that water vapor exerts a substantial influence on the ability of commercial hydrated lime to retain SO2 in flue gas desulfurization (FGD) technologies. A reaction mechanism consistent with the experimental observations and with its kinetic implications is discussed. © 2006 American Institute of Chemical Engineers AIChE J, 2006
Cross‐genus adoption of a marmoset (Callithrix jacchus) by wild capuchin monkeys (Cebus libidinosus): case report
Authors: Izar Patrícia , Verderane Michele P. , Visalberghi Elisabetta , Ottoni Eduardo B. , Gomes De Oliveira Marino , Shirley Jeanne , Fragaszy Dorothy
Published: June 2006

We report a case of interspecies adoption of an infant marmoset (Callithrix jacchus) by wild capuchin monkeys (Cebus libidinosus). The marmoset was an infant when it was first observed in the capuchin group on 3 March 2004. Since it first appeared it has been observed informally and frequently. In January 2005 systematic observations were made of the marmoset and a capuchin of similar age. Throughout its period of adoption the marmoset appeared to be socially integrated into the group, benefiting from nurturant behaviors exhibited by two successive adoptive “mothers” and pronounced tolerance from all members of the group. This case highlights the flexibility of both Callithrix and Cebus in accommodating variable social behaviors and other characteristics (including size) of social partners. Am. J. Primatol. 68:692–700, 2006. © 2006 Wiley‐Liss, Inc.
Curing behavior, mechanical properties, intermolecular interaction, and morphology of silicone/polypyrrole/polymer electrolyte composites
Authors: Chiu Hsien‐Tang , Wu Jyh‐Horng
Published: June 2006

The curing behavior, mechanical properties, intermolecular interaction, and morphology of silicone, polypyrrole, and polymer electrolyte composites were studied. A rigid‐body pendulum rheometer was used to determine the curing behavior of silicone/PEL blends. The polymer structure was evaluated using FTIR and Differential Scanning Calorimetery. The mechanical properties, including stress, strain, and hardness, were measured using a material testing system. The morphology of the composites was measured using scanning electron micrographs. The intermolecular interaction of the composites was measurement using dynamic mechanical analysis. The results show that the curing reaction rate is fast upon addition of 10 wt % of polymer electrolyte for silicone. The linear molecular structure of the polymer electrolyte was wound around the silicone polymer network structure forming a semi‐interpenetrating network. The intermolecular interaction was influenced by the composites, and the Ppy film effect on the surface of SP10 blends is more uniform than that of silicone. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 2754–2764, 2006
Phase interactions and structure evolution of heterophasic ethylene–propylene copolymers as a function of system composition
Authors: Doshev P. , Lohse G. , Henning S. , Krumova M. , Heuvelsland A. , Michler G. , Radusch H.‐J.
Published: June 2006

Heterophasic copolymers comprised of polypropylene (PP) matrix and ethylene–propylene copolymer (EPC) dispersed phase were investigated with respect to the dispersed phase composition, i.e., ethylene/propylene ratio. The rheological properties, morphology, as well as thermal and mechanical relaxation behavior were studied to describe the structure evolution and phase interactions between the components of the PP copolymers. Decrease of the ethylene content of the EPC leads to a higher matrix‐dispersed phase compatibility, as evaluated by the shift of the glass transition temperatures of EPC and PP towards each other. At ethylene content of EPC of 17 wt %, the glass transition temperatures of the both phases merged into a joint relaxation. The effect of the EPC composition on the internal structure of the dispersed domains and on the morphology development of the heterophasic copolymers was demonstrated. Decreasing ethylene content was found to induce a refinement of the dispersed phase with several orders of magnitude down to 0.18 μm for propylene‐rich EPC. Optical microscopy observations showed that the dispersed propylene‐rich phase is preferably rejected at the interlamellar regions of the spherulites and/or at the interspherulitic regions, while the ethylene‐rich domains are engulfed within the PP spherulites. Both of these processes impose an additional energetic barrier and influence the spherulite growth rate of the heterophasic materials. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 2825–2837, 2006
The rheological behavior of EPDM Nordel IP and POE engage produced by CGC and INSITE™ technology
Authors: Qiye Wu , Peng Li , Jingxia Mu , Na Zhang , Peng An , Jingan Wu
Published: June 2006

The rheological behavior of EPDM Nordel and POE Engage produced by CGC and INSITE™ technology are studied with double capillary rheometer of constant speed type. It is indicated that the melt viscosity of EPDM Nordel IP 3745P is higher and the nonlinear fluidity is stronger compared with Nordel IP 3722P, because the molecular weight of Nordel IP 3745P is higher and the MWD is narrow. We compare the melt viscosity of POE Engage GPE8003 with that of Engage GPE8150, and indicate that the influence of temperature on viscosity of Engage GPE8003 is obvious and the influence of shear rate on viscosity of Engage GPE8150 is stronger, which was related to the octene percent in material. The melt slide at wall and the extrusion pressure vibration occurred with EPDM Nordel IP 3745P. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 2847–2853, 2006
Rheological kinetics of acrylonitrile/amino ethyl‐2‐methyl propenoate copolymer solutions in dimethyl sulfoxide
Authors: Hou Chen , Qu Rongjun , Ji Chunnuan , Ying Liang
Published: June 2006

Viscosity behavior of dimethyl sulfoxide solutions of acrylonitrile (AN)/amino ethyl‐2‐methyl propenoate (AEMP) copolymer was discussed. Rheological kinetics of the solutions was studied in contrast. It is shown that the solutions behave the same as Newtonian flow as the rotor speed goes beyond 12 rpm. With an increase of temperature, the apparent viscosity of AN/AEMP copolymer solutions shows a trend of decrease. The changes of the apparent flow activation energy of solutions calculated by Arrhenius equation become less prominent along with the changes of the molecular weight of AN/AEMP copolymers. The apparent flow activation energy of the copolymer solutions increases continuously with an increase of copolymer concentration. The viscosity of copolymer solutions decreases continuously as the concentrations of KCl and NaCl up to 0.02 mol L−1, and then it increases. the apparent flow‐activation energy of AN/AEMP copolymer solutions shows an obvious trend of decrease with addition of alkali salts and the changes of the apparent flow‐activation energy of solutions containing NaCl are more prominent than those of solutions containing KCl. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 2972–2976, 2006
Effect of talc on the properties of polypropylene/ethylene/propylene/diene terpolymer blends
Authors: Öksüz Mustafa , Eroglu Mehmet , Yıldırım Hüseyin
Published: June 2006

In the present study, the effect of talc content on the mechanical, thermal, and microstructural properties of the isotactic polypropylene (i‐PP) and elastomeric ethylene/propylene/diene terpolymer (EPDM) blends were investigated. In the experimental study, five different talc concentrations, 3, 6, 9, 12, and 15 wt %, were added to i‐PP/EPDM (88/12) blends to produce ternary composites. The mechanical properties such as yield and tensile strengths, elongation at break, elasticity modulus, izod impact strength for notch tip radius of 1 mm, and hardness with and without heat treatments and thermal properties, such as melt flow index (MFI), of the ternary composites have been investigated. The annealing heat treatment was carried out at 100°C for holding time of 75 h. From the tensile test results, an increased trend for the yield and tensile strengths and elasticity modulus was seen for lower talc contents, while elongation at break showed a sharp decrease with the addition of talc. In the case of MFI, talc addition decreased the MFI of i‐PP/EPDM blends. It was concluded that, taking into consideration, mechanical properties and annealing heat treatment, heat treatment has much more effect on higher yield and tensile strengths, elongation at break, elasticity modulus, impact strength, and hardness. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 3033–3039, 2006
Thermoplastic vulcanizates based on epoxidized natural rubber/polypropylene blends: Effect of epoxide levels in ENR molecules
Authors: Nakason Charoen , Wannavilai Puripong , Kaesaman Azizon
Published: June 2006

Epoxidized natural rubbers (ENR) with various levels of epoxide groups were prepared. Thermoplastic vulcanizates based on 75/25 ENRs/PP blends with Ph‐PP compatibilizer were later prepared by dynamic vulcanization using sulfur curing system. Influence of various levels of epoxide groups on rheological, mechanical morphological properties, and swelling resistance of the TPVs was investigated. It was found that the mixing torque, apparent shear stress, apparent shear viscosity, tensile strength, and hardness properties increased with increasing levels of epoxide groups in the ENR molecules. This may be attributed to increasing level of chemical interaction between the methylol groups of the Ph‐PP molecules and polar functional groups of the ENR molecules. Also, the PP segments in the Ph‐PP molecules are capable of compatibilizing with the PP molecules used as a blend composition. In SEM micrographs, we observed finer dispersion of vulcanized rubber domains as increasing levels of epoxide contents. This corresponds to increasing trend of strength and hardness properties of the TPVs. An increasing trend of tension set and a decreasing trend of elongation at break were observed as increasing levels of epoxide groups in the ENR molecules. This is because of higher rigidity of the vulcanized ENR phase with higher epoxide groups. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 3046–3052, 2006
Dynamic interfacial tension between a thermotropic liquid‐crystalline polymer and a flexible polymer
Authors: Yu Ruobing , Yu Wei , Zhou Chixing , Feng J. J.
Published: June 2006

When a short fiber of a thermotropic liquid‐crystalline polymer retracts in a quiescent, flexible polymer matrix, the polydomain texture inside the fiber evolves simultaneously. We have demonstrated experimentally that the two processes are coupled. The dynamic interfacial tension, determined from the retraction of the short fiber, decreases with time. On the other hand, we have determined the aspect ratio of the polydomains inside the fiber through the power spectra of two‐dimensional discrete Fourier transformations of polarized optical microscopy images. The polydomains are initially elongated and aligned with the fiber axis. As the fiber retracts into a spherical drop, the polydomains first retract into a circular shape and then are squeezed into elongated shapes perpendicular to the original fiber axis. An exponential function correlates the evolution of the dynamic interfacial tension with that of the aspect ratio of the textures. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 3114–3120, 2006
Towards the algorithmic treatment of 3D strong discontinuities
Authors: Mergheim J. , Kuhl E. , Steinmann P.
Published: June 2006

A geometrically non‐linear finite element framework for the modelling of propagating discontinuities in three‐dimensional continua is presented. By doubling the degrees of freedom in the discontinuous elements, the algorithm allows for arbitrary discontinuities which are not restricted to inter‐element boundaries. The deformation field is interpolated independently on both sides of the discontinuity. In contrast to the X‐FEM, the suggested approach thus relies exclusively on displacement degrees of freedom. On the discontinuity surface, the jump in the deformation is related to the cohesive tractions to account for smooth crack opening. Computational difficulties characteristic of three‐dimensional crack propagation are addressed. The performance of the method is elaborated by means of a homogeneous three‐dimensional tension problem and by means of the classical peel test. Copyright © 2006 John Wiley & Sons, Ltd.
Role for retinoid signaling in left–right asymmetric digestive organ morphogenesis
Authors: Lipscomb Kristen , Schmitt Christopher , Sablyak Amanda , Yoder Jeffrey A. , Nascone‐Yoder Nanette
Published: June 2006

The looping events that establish left–right asymmetries in the vertebrate gut tube are poorly understood. Retinoic acid signaling is known to impact left–right development in multiple embryonic contexts, although its role in asymmetric digestive organ morphogenesis is unknown. Here, we show that the genes for retinaldehyde dehydrogenase (RALDH2) and a retinoic acid hydroxylase (CYP26A1) are expressed in complementary patterns in the Xenopus gut during looping. A late‐stage chemical genetic assessment reveals that agonists and antagonists of retinoid signaling generate abnormal gut looping topologies, digestive organ heterotaxias, and intestinal malrotations. Accessory organ deformities commonly associated with intestinal malrotation in humans, such as annular pancreas, pancreas divisum, and extrahepatic biliary tree malformations, are also induced by distinct retinoid receptor agonists. Thus, late‐stage retinoic acid signaling is likely to play a critical role in asymmetric gut tube morphogenesis and may underlie the etiology of several clinically relevant defects in the digestive system. Developmental Dynamics 235:2266–2275, 2006. © 2006 Wiley‐Liss, Inc.
Optimal network configuration of FRIENDS taking power supply reliability into account
Authors: Nara Koichi , Satoh Taiji , Mishima Yuji
Published: June 2006

FRIENDS (Flexible, Reliable and Intelligent ENergy Delivery System) is a new concept for a future power delivery system in which so‐called QCC (Quality Control Center) plays an important role to realize the customized power quality services and to connect a large number of distributed generators to distribution systems. In FRIENDS, QCCs are connected as a network through distribution cables to realize a reliable power supply. In this paper, a method to find the optimal network configuration of FRIENDS is proposed. The method can minimize the sum of facility installation cost and operational cost (distribution loss) under the constraint that the expected power interruption cost is less than a predetermined endurable value. The solution algorithm is based on tabu search, and employs a sensitivity analysis to select efficient facilities to be installed or to eliminate constraint violations. In the algorithm, single and double faults of power distribution system are taken into account to calculate the power supply reliability or expected power interruption cost. Several numerical real‐world examples are shown to demonstrate the validity of the algorithm. © 2006 Wiley Periodicals, Inc. Electr Eng Jpn, 156(3): 32–40, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20264
Generator control based on equilibrium point analysis of standard one‐machine infinite‐bus system model: Comparison with PSS
Authors: Kawamoto Shunji , Zhang Jian , Yamamoto Hiroyoshi , Fujimoto Koji
Published: June 2006

We have recently proposed a new controller based on equilibrium point analysis for power system models. In this paper, first the Japanese standard one‐machine infinite‐bus system model is formulated, and the equilibrium points are analyzed. Next, complementary control inputs for AVR and GOV with limiters of the system model are determined on the basis of the analysis. Finally, it is shown that the unstable equilibrium point is eliminated by adding the proposed inputs, and then the critical clearing time can be improved in comparison with PSS of the standard model. © 2006 Wiley Periodicals, Inc. Electr Eng Jpn, 156(3): 16–23, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20359
Discussion on classification of impulsive EM noises emitted from power apparatus
Authors: Nakata Syo , Hirata Akimasa , Kawasaki Zen‐Ichiro
Published: June 2006

This paper proposes an automatic classification system for impulsive electromagnetic (EM) noises. The classification is based on the frequency spectrum of EM waves emitted from partial discharges in power apparatus. This concept is validated by confirming the reproducibility of waveforms of EM waves. In order to clarify the effectiveness of our proposal, six defects are considered: a needle‐plane electrode, a strain insulator, a pin‐type insulator, FDF (Forced Draft Fan), CBP (Condensate Booster Pump), and COOL‐P (Cooling Water Pump). Neural networks are used to classify the frequency spectrum of EM waves. As a main result, these sources are well classified with a recognition rate of 80% or better. This is supported by treating 1000 EM pulses. © 2006 Wiley Periodicals, Inc. Electr Eng Jpn, 156(3): 1– 8, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20378
A novel optical receiver structure combining wavelength conversion and homodyne detection
Authors: Conesa J. , Comellas J. , Zaragoza A. , Junyent G.
Published: June 2006

A new optical receiver scheme which combines wavelength conversion and homodyne detection is proposed and its performance is analysed by means of simulation. The main advantage of the proposed structure stems from the use of the same laser source for both, the wavelength conversion and the homodyne detection blocks, avoiding the use of any optical phase‐locking loop. Results obtained show an improvement of the main performance parameters when compared with typical direct detection or homodyne receivers. Copyright © 2006 AEIT.
New super‐orthogonal space‐time trellis codes with 32QAM and two transmit antennas for five bits per signalling interval
Authors: Sterian Corneliu Eugen D. , Linga Srujan , Singh Harvinder , Pätzold Matthias
Published: June 2006

In this paper, we focus on the design of super‐orthogonal space‐time (ST) trellis codes with a 32‐point quadrature amplitude modulation (QAM) signal constellation, allowing wireless communication with a data rate of 5 bits per signalling interval. Considering a mobile wireless communications system with two transmit antennas, we form a four‐dimensional (4D) signal constellation as a Cartesian product of two 2D rectangular signal sets. The first antenna transmits a 4D point as two concatenated 2D points in two consecutive baud intervals. The 2D symbols transmitted by the second antenna are not independent, but so chosen as to form, together with the symbols transmitted by the first antenna, the entries of a 2 × 2 orthogonal matrix. For a rectangular constellation, as much as four sets of 2 × 2 orthogonal matrices can be built. To obtain a higher data rate, the union of two of them is used to construct a super‐orthogonal signal set. With 2 × 2 orthogonal matrices, we then label the state transitions of a trellis diagram describing the operation of the encoder. For the performance analysis, two different channel models are employed. The first channel model is based on the assumption that the paths between different pairs of transmit–receive antennas are uncorrelated, while the second model takes into account the effect of spatial antenna correlation at both the base station (BS) and at the mobile station (MS). The analysis of the frame‐error rate (FER) and the bit‐error rate (BER) demonstrates the excellent performance of the proposed high data rate super‐orthogonal ST trellis code. Copyright © 2006 AEIT.
Finite volume adaptive solutions using SIMPLE as smoother
Authors: Syrakos Alexandros , Goulas Apostolos
Published: June 2006

This paper describes a new multilevel procedure that can solve the discrete Navier–Stokes system arising from finite volume discretizations on composite grids, which may consist of more than one level. SIMPLE is used and tested as the smoother, but the multilevel procedure is such that it does not exclude the use of other smoothers. Local refinement is guided by a criterion based on an estimate of the truncation error. The numerical experiments presented test not only the behaviour of the multilevel algebraic solver, but also the efficiency of local refinement based on this particular criterion. Copyright © 2006 John Wiley & Sons, Ltd.
A new modification of the immersed‐boundary method for simulating flows with complex moving boundaries
Authors: Deng Jian , Shao Xue‐Ming , Ren An‐Lu
Published: June 2006

In this paper, a new immersed‐boundary method for simulating flows over complex immersed, moving boundaries is presented. The flow is computed on a fixed Cartesian mesh and the solid boundaries are allowed to move freely through the mesh. The present method is based on a finite‐difference approach on a staggered mesh together with a fractional‐step method. It must be noted that the immersed boundary is generally not coincident with the position of the solution variables on the grid, therefore, an appropriate strategy is needed to construct a relationship between the curved boundary and the grid points nearby. Furthermore, a momentum forcing is added on the body boundaries and also inside the body to satisfy the no‐slip boundary condition. The immersed boundary is represented by a series of interfacial markers, and the markers are also used as Lagrangian forcing points. A linear interpolation is then used to scale the Lagrangian forcing from the interfacial markers to the corresponding grid points nearby. This treatment of the immersed‐boundary is used to simulate several problems, which have been validated with previous experimental results in the open literature, verifying the accuracy of the present method. Copyright © 2006 John Wiley & Sons, Ltd.
Tracking accuracy of a semi‐Lagrangian method for advection–dispersion modelling in rivers
Authors: Néelz S. , Wallis S. G.
Published: June 2006

There is an increasing need to improve the computational efficiency of river water quality models because: (1) Monte‐Carlo‐type multi‐simulation methods, that return solutions with statistical distributions or confidence intervals, are becoming the norm, and (2) the systems modelled are increasingly large and complex. So far, most models are based on Eulerian numerical schemes for advection, but these do not meet the requirement of efficiency, being restricted to Courant numbers below unity. The alternative of using semi‐Lagrangian methods, consisting of modelling advection by the method of characteristics, is free from any inherent Courant number restriction. However, it is subject to errors of tracking that result in potential phase errors in the solutions. The aim of this article is primarily to understand and estimate these tracking errors, assuming the use of a cell‐based backward method of characteristics, and considering conditions that would prevail in practical applications in rivers. This is achieved separately for non‐uniform flows and unsteady flows, either via theoretical considerations or using numerical experiments. The main conclusion is that, tracking errors are expected to be negligible in practical applications in both unsteady flows and non‐uniform flows. Also, a very significant computational time saving compared to Eulerian schemes is achievable. Copyright © 2006 John Wiley & Sons, Ltd.
A combined pFFT‐multipole tree code, unsteady panel method with vortex particle wakes
Authors: Willis David J. , Peraire Jaime , White Jacob K.
Published: June 2006

Potential flow solvers for 3‐D aerodynamic flows are commonly used in industrial applications. Two main difficulties preventing the even more widespread use of these codes are the limitations on the number of discretization elements and the user expertise and effort required to specify the wake location. In the paper we present an automatic wake generation strategy for a potential flow solver, and accelerate the method using a pFFT‐Fast Multipole Tree algorithm. The combined method can be used to simulate both steady and unsteady flows. The steady state solution is achieved by running an unsteady flow simulation until it reaches a steady state. Computation results are given to demonstrate that the method is fast enough to automatically simulate entire heaving and flapping wing crafts in under and hour on a desktop computer. Copyright © 2006 John Wiley & Sons, Ltd.
An eigenvector‐based linear reconstruction scheme for the shallow‐water equations on two‐dimensional unstructured meshes
Authors: Frazão Sandra Soares , Guinot Vincent
Published: June 2006

This paper presents a new approach to MUSCL reconstruction for solving the shallow‐water equations on two‐dimensional unstructured meshes. The approach takes advantage of the particular structure of the shallow‐water equations. Indeed, their hyperbolic nature allows the flow variables to be expressed as a linear combination of the eigenvectors of the system. The particularity of the shallow‐water equations is that the coefficients of this combination only depend upon the water depth. Reconstructing only the water depth with second‐order accuracy and using only a first‐order reconstruction for the flow velocity proves to be as accurate as the classical MUSCL approach. The method also appears to be more robust in cases with very strong depth gradients such as the propagation of a wave on a dry bed. Since only one reconstruction is needed (against three reconstructions in the MUSCL approach) the EVR method is shown to be 1.4–5 times as fast as the classical MUSCL scheme, depending on the computational application. Copyright © 2006 John Wiley & Sons, Ltd.
Application of Chimera grid to modelling cell motion and aggregation in a narrow tube
Authors: Chung B. , Johnson P. C. , Popel A. S.
Published: June 2006

A computational scheme using the Chimera grid method is presented for simulation of three‐dimensional motion and aggregation of two red blood cells (RBCs) in a narrow tube. The cells are modelled as rigid ellipsoidal particles; the computational scheme is applicable to deformable fluid‐filled particles. Attractive energy between two RBCs is modelled by a depletion interaction theory and used for simulating aggregation of two cells. Through the simulation, we show that the Chimera grid method is applicable to the simulation of three‐dimensional motion and aggregation of multiple RBCs in a microvessel and microvascular network. Copyright © 2006 John Wiley & Sons, Ltd.
Compressible flow equations based on moving coordinates determined by the wave speed
Authors: Chen Zheng , Gao Bo , Wu Zi‐Niu
Published: June 2006

In this paper, we consider moving coordinates with a speed determined by the wave speed. This allows us to move the coordinates at the speed of contact discontinuities, expansion fans, or other wave structures. While recognizing that the Lagrangian coordinates, which can well resolve the sliplines, behave badly for expansion waves, we demonstrate that a coordinate system moving at the characteristic speed of the expansion fan behaves much better for expansion waves. Moreover, the new coordinate system allows one to well capture the shock wave, the slipline and the expansion waves at the same time. Copyright © 2006 John Wiley & Sons, Ltd.
Lattice Boltzmann‐based single‐phase method for free surface tracking of droplet motions
Authors: Xing Xiu Qing , Butler David Lee , Yang Chun
Published: June 2006

A 2D single‐phase free surface tracking model, based on the lattice Boltzmann method (LBM) is developed for simulating droplet motion. In contrast to the conventional multi‐phase models, it is not necessary to simulate the motion of the gas phase using this 2D single‐phase algorithm, and thus improves the computational efficiency without sacrificing the underlying physics. A method for special treatment of the relevant boundary conditions in the single‐phase algorithm is proposed and also validated. Numerical simulations are carried out for the motion of a free falling droplet with or without considering gravity and droplet spreading under gravity. The simulations of the LBM are found to be consistent with the results obtained from commercial computational fluid dynamics (CFD) software Fluent. Copyright © 2006 John Wiley & Sons, Ltd.
Antibiotic prophylaxis in chemotherapy‐induced neutropenia: time to reconsider
Authors: Lo Nangi , Cullen Michael
Published: June 2006

The use of antibiotic prophylaxis in neutropenic patients remains controversial. The main arguments against prophylaxis are the lack of survival benefit and the risk of inducing antibiotic resistance. At present, clinical guidelines advise against routine use of antibiotic prophylaxis and current practice is to commence broad‐spectrum antibiotics at the onset of fever in the neutropenic patient. However hospitalization, investigations and treatment all impact on resources as well as affecting patient quality of life, often resulting in chemotherapy delays and dose reductions. The benefits of prophylactic antibiotics have been emphasized by two major double‐blind, placebo controlled trials with levofloxacin with very significant reductions in all infection‐related events. Furthermore, the meta‐analysis confirms a survival advantage and this is greatest with the use of fluoroquinolones. These benefits must be weighed against the problem of emerging antibiotic resistance. It has been shown that antibiotic prophylaxis does induce resistant organisms, but some studies have shown that the impact on clinical outcomes may not be as great as expected. Current evidence supports antibiotic prophylaxis with fluoroquinolones in acute leukaemia and high‐dose chemotherapy patients, commencing at the same time as chemotherapy. Febrile episodes are much commoner with the first cycle in patients with solid tumours or lymphoma having moderately myelosuppressive chemotherapy, and these patients should be offered prophylaxis for at least the first cycle of chemotherapy. Further work is ongoing to facilitate the selection of patients with the greatest chance of benefit so that prophylaxis can be used efficiently. Copyright © 2006 John Wiley & Sons, Ltd.
Theoretical, spectroscopic, and mechanistic studies on transition‐metal dinitrogen complexes: Implications to reactivity and relevance to the nitrogenase problem
Authors: Studt Felix , Tuczek Felix
Published: June 2006

Dinitrogen complexes of transition metals exhibit different binding geometries of N2 (end‐on terminal, end‐on bridging, side‐on bridging, side‐on end‐on bridging), which are investigated by spectroscopy and DFT calculations, analyzing their electronic structure and reactivity. For comparison, a bis(μ‐nitrido) complex, where the NN bond has been split, has been studied as well. Most of these systems are highly covalent, and have strong metal–nitrogen bonds. In the present review, particular emphasis is put on a consideration of the activation of the coordinated dinitrogen ligand, making it susceptible to protonation, reactions with electrophiles or cleavage. In this context, theoretical, structural, and spectroscopic data giving informations on the amount of charge on the N2 unit are presented. The orbital interactions leading to a charge transfer from the metals to the dinitrogen ligand and the charge distribution within the coordinated N2 group are analyzed. Correlations between the binding mode and the observed reactivity of N2 are discussed. © 2006 Wiley Periodicals, Inc. J Comput Chem 27: 1278–1291, 2006
Whole‐body T1 mapping improves the definition of adipose tissue: Consequences for automated image analysis
Authors: Kullberg Joel , Angelhed Jan‐Erik , Lönn Lars , Brandberg John , Ahlström Håkan , Frimmel Hans , Johansson Lars
Published: June 2006

Purpose

To determine whether a whole‐body T1‐mapping acquisition method improves the definition of adipose tissue (AT) and simplifies automated AT segmentation compared to an image‐based method.

Materials and Methods

The study included 10 subjects. Two whole‐body volumes were acquired from each subject using two different flip angles. Whole‐body T1 maps were calculated from each pair of whole‐body volumes. AT was automatically segmented from the T1 maps and from the original image slices. The results were evaluated using manually segmented slices as reference.

Results

The T1‐mapping method segmented more of the reference AT than the image‐based method, with mean values (standard deviations (SDs)) of 87.7(5.1)% and 81.1(5.2)%, respectively. Compared to the image‐based method, the T1‐mapping method gives better histogram separation of AT in whole‐body volumes. The suggested method also provides an output with smaller in‐slice AT intensity variations.

Conclusion

The T1‐mapping method improves the definition of AT. T1‐based analysis is superior to analysis based on the original images, and allows fully automated and accurate whole‐body AT segmentation. J. Magn. Reson. Imaging 2006. © 2006 Wiley‐Liss, Inc.
Study on the toxic mechanism of prion protein peptide 106–126 in neuronal and non neuronal cells
Authors: Dupiereux Ingrid , Zorzi Willy , Rachidi Walid , Zorzi Danièle , Pierard Olivier , Lhereux Bernard , Heinen Ernst , Elmoualij Benaïssa
Published: June 2006

A synthetic peptide corresponding to the 106–126 amyloidogenic region of the cellular human prion protein (PrPc) is useful for in vitro study of prion‐induced neuronal cell death. The aim of the present work was to examine the implication of the cellular prion protein in the toxicity mechanism induced by PrP 106–126. The effect of PrP 106–126 was investigated both on human neuroblastoma SH‐SY5Y cells and on SH‐SY5Y overexpressing murine cellular prions (wtPrP). We show by metabolic assay tests and ATP assays that PrPc expression does not modulate the toxicity of the prion peptide. Moreover, we investigated the effect of this peptide on an established non neuronal model, rabbit kidney epithelial A74 cells that express a doxycycline‐inducible murine PrPc gene. We show for the first time that the prion peptide 106–126 does not exert any toxic effect on this cell line in the presence or absence of doxycycline. Our results show that the PrP 106–126‐induced cell alteration is independent of PrPc expression. Rather, it seems to act via an interaction with lipidic components of the plasma membrane as strengthened by our results showing the differential susceptibility of neuronal and non neuronal cell lines that significantly differ by their membrane fatty acid composition. © 2006 Wiley‐Liss, Inc.
Sugar and acid concentrations in 98 grape cultivars analyzed by principal component analysis
Authors: Liu Huai‐Feng , Wu Ben‐Hong , Fan Pei‐Ge , Li Shao‐Hua , Li Lian‐Sheng
Published: June 2006

A total of 98 grape cultivars were studied for content and composition of organic acids and sugars in grape juice during two consecutive years. Glucose and fructose were the predominant sugars in grape berries and ranged from 45.86 to 122.89 mg mL−1, and 47.64 to 131.04 mg mL−1, respectively, in two years. Sucrose was present at trace amounts in most cultivars, but two cultivars of hybrids between Vitis labrusca and V. vinifera contained large amounts of sucrose. Tartaric acid content in berries, varying from 1.57 to 9.09 and 1.54 to 9.05 mg mL−1, respectively, in two years, was significantly higher than malic acid, which ranged from 0.38 to 6.05 and 0.36 to 7.06 mg mL−1, respectively, in two years. Moreover, significantly higher total soluble sugars and fructose and lower total acids and malic acid were found in cultivars from hybrids between V. labrusca and V. vinifera than those in V. vinifera cultivars, and wine grapes had higher total sugars and acids than table grapes from V. vinifera. Principal component analysis (PCA) indicated that genotypic correlations among sugar and acid contents were stable and the first three PCs accounted for about 82% of total variance in both years. PC1 was highly connected with glucose and fructose contents, and sucrose was an important contributor to the variance for PC2, as well as for PC3. PC2 and PC3 were highly connected also with organic acids, but the contributor to variance differed from one year to the next. Tartaric acid was the main contributor to variance in 2003, and malic acid was important in 2004 for PC2 and PC3. In a scatter plot of the score values of all genotypes projected to the PC1 and PC2 plane, three groups of cultivars tend to cluster based on their genetic background or purpose of use. The cultivars of hybrid V. labrusca and V. vinifera were represented by high sugars, especially sucrose, and low acids. Among the cultivars of V. vinifera, wine grapes were found in general to have more sugars and acids than table grapes. The composition of sugars was stable in grape berries between the two years, while acids were sensitive to climate changes. Finally, the different responses of malic and tartaric acids to climate change is discussed. Copyright © 2006 Society of Chemical Industry
Effect of drying conditions on bioactive compounds and antioxidant activity of broccoli (Brassica oleracea L.)
Authors: Mrkìc Vlatka , Cocci Emiliano , Rosa Marco Dalla , Sacchetti Giampiero
Published: June 2006

The effect of air‐drying parameters on antioxidant activity and changes in antioxidant compounds of broccoli (Brassica oleracea L.) were studied. Broccoli samples were dried to 70 g kg−1 moisture content using temperatures ranging from 50 to 100 °C and air flow‐rates from 1.20 to 2.25 m s−1, resulting in drying times from 25 to 90 min. Temperature, owing to its positive effect on the oxidation kinetics, was negatively correlated with ascorbic acid and free and total polyphenol contents but not with kaempferol, even though the sample dried at the highest temperature showed the lowest kaempferol content. The air flow‐rate was positively correlated with the total (TPP) and free (FPP) polyphenol contents because it led to a reduction in the drying time. No correlation was found between air flow‐rate and kaempferol content. Air flow‐rate and temperature positively affected the antioxidant activity by reducing the drying time. High‐temperature, short‐time processes maximised the antioxidant activity of broccoli owing to the negative effect of drying time on antioxidant activity. The antioxidant activity of broccoli was positively and significantly correlated with the FPP content but not with TPP and kaempferol. The evaluation of hydroxymethylfurfural content as an indicator of the occurrence of a Maillard reaction in dried broccoli did not support the hypothesis of a contribution of MRPs to the antioxidant activity of dried broccoli. Copyright © 2006 Society of Chemical Industry
Discrete duality finite volume schemes for Leray−Lions−type elliptic problems on general 2D meshes
Authors: Andreianov Boris , Boyer Franck , Hubert Florence
Published: June 2006

Discrete duality finite volume schemes on general meshes, introduced by Hermeline and Domelevo and Omnès for the Laplace equation, are proposed for nonlinear diffusion problems in 2D with nonhomogeneous Dirichlet boundary condition. This approach allows the discretization of non linear fluxes in such a way that the discrete operator inherits the key properties of the continuous one. Furthermore, it is well adapted to very general meshes including the case of nonconformal locally refined meshes. We show that the approximate solution exists and is unique, which is not obvious since the scheme is nonlinear. We prove that, for general W−1,p′(Ω) source term and W1‐(1/p),p(∂Ω) boundary data, the approximate solution and its discrete gradient converge strongly towards the exact solution and its gradient, respectively, in appropriate Lebesgue spaces. Finally, error estimates are given in the case where the solution is assumed to be in W2,p(Ω). Numerical examples are given, including those on locally refined meshes. © 2006 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq, 2007
Structural characterization and mass transfer properties of polyurethane block copolymer: influence of mixed soft segment block and crystal melting temperature
Authors: Mondal Subrata , Hu JinLian
Published: June 2006

An attempt has been made to investigate the influence of mixed soft segment on structure and mass transfer properties of segmented polyurethane (SPU). For this purpose polyurethane block copolymer containing soft segment such as polycaprolactone glycol (number‐average molecular weight 3000, PCL 3000), PCL 3000–polypropylene glycol (number‐average molecular weight 3000, PPG 3000), PCL 3000–polytetramethylene glycol (number‐average molecular weight 2900, PTMG 2900), PPG 3000–PTMG 2900, were synthesized using a two‐step or three‐step synthesis process. All the SPUs were modified with the hydrophilic segment, i.e. diol‐terminated poly(ethylene oxide) (number‐average molecular weight 3400, PEG 3400). Fourier‐transform infrared, wide‐angle X‐ray diffraction, differential scanning calorimetry, and dynamic mechanical thermal analysis were used to characterize the polyurethanes. The mass transfer properties were measured by equilibrium sorption and water vapor permeability measurements. Mixed blocks loosen the inter‐chain interaction due to phase mixing which decreases the crystallization of the soft segment in the resulting SPU. The crystallinity of mixed polyol block SPU increases when both polyols are crystallizable in the pure state. Highest loss tan δ value was observed for the sample containing PTMG 2900–PPG 3000 mixed soft segment due to their flexible and phase mixed structure which increases the chain mobility; this sample performed best among all four SPUs in equilibrium water sorption as well as water vapor permeability owing to their loose and nearly amorphous structure. Soft segment crystal melting further enhances the water vapor permeability significantly, which would make the membrane suitable for breathable textiles, packaging and medical applications. Copyright © 2006 Society of Chemical Industry