bluuebunny/crossref_metadata_2025_split huggingface dataset:
Covalent bonding of azoles to quaternary protoberberine alkaloids
Authors: Grycová Lenka , Hulová Dagmar , Maier Lukáš , Standara Stanislav , Nečas Marek , Lemière Filip , Kareš Radovan , Dostál Jiří , Marek Radek 
Published: October 2008

AbstractAdducts of the quaternary protoberberine alkaloids (QPA) berberine, palmatine, and coptisine were prepared with nucleophiles derived from pyrrole, pyrazole, imidazole, and 1,2,4‐triazole. The products, 8‐substituted 7,8‐dihydroprotoberberines, were identified by mass spectrometry and 1D and 2D NMR spectroscopy, including 1H15N shift correlations at natural abundance. In addition, two adducts of QPA with chloroform and methanethiolate were characterized by using NMR data. Single‐crystal X‐ray structures of 8‐pyrrolyl‐7,8‐dihydroberberine, 8‐pyrazolyl‐7,8‐dihydroberberine, and 8‐imidazolyl‐7,8‐dihydroberberine are also presented. Copyright © 2008 John Wiley & Sons, Ltd.
Hydroacridines: part 29.15N NMR chemical shifts of 9‐substituted 1,2,3,4,5,6,7,8‐octahydroacridines and theirN‐oxides—Taft, Swain–Lupton, and other types of linear correlations
Authors: Potmischil Francisc , Marinescu Maria , Nicolescu Alina , Deleanu Călin , Hillebrand Mihaela 
Published: October 2008

AbstractThe15N NMR chemical shifts of 1,2,3,4,5,6,7,8‐octahydroacridine, 12 of its 9‐substituted derivatives, and of the correspondingN‐oxides were measured and examined in terms of the 9‐substituent effects and the effects ofN‐oxidation. For the 9‐substituent effects, good linear correlations were found with the Taft and Swain‐Lupton substituent constants, for both octahydroacridines and theirN‐oxides. The15N chemical shifts of both octahydroacridines and theirN‐oxides also correlate well, linearly with the13C chemical shifts of thepara‐carbons in analogously substituted benzene derivatives.Within the studied compounds, the magnitudes of theN‐oxidation effects range from − 16.4 to − 27.4 ppm (shielding), and also correlate linearly with the Taft and Swain–Lupton substituent constants, as well as with the bond orders of the N+O−bonds in the correspondingN‐oxides. Furthermore, a very good linear correlation is found between the15N chemical shifts of octahydroacridines and those of the correspondingN‐oxides. From the15N chemical shifts data, the Taft and Swain‐Lupton substituent constants for the diacetylamino group (NAc2) were evaluated in the present paper, as follows: σR= 0.07 and σI= 0.15;${{\cal R}} = 0.08$and${{\cal F}} = 0.20$. Copyright © 2008 John Wiley & Sons, Ltd.
Imaging the tissue distribution of glucose in livers using a PARACEST sensor
Authors: Ren Jimin , Trokowski Robert , Zhang Shanrong , Malloy Craig R. , Sherry A. Dean 
Published: October 2008

AbstractNoninvasive imaging of glucose in tissues could provide important insights about glucose gradients in tissue, the origins of gluconeogenesis, or perhaps differences in tissue glucose utilization in vivo. Direct spectral detection of glucose in vivo by 1H NMR is complicated by interfering signals from other metabolites and the much larger water signal. One potential way to overcome these problems is to use an exogenous glucose sensor that reports glucose concentrations indirectly through the water signal by chemical exchange saturation transfer (CEST). Such a method is demonstrated here in mouse liver perfused with a Eu3+‐based glucose sensor containing two phenylboronate moieties as the recognition site. Activation of the sensor by applying a frequency‐selective presaturation pulse at 42 ppm resulted in a 17% decrease in water signal in livers perfused with 10 mM sensor and 10 mM glucose compared with livers with the same amount of sensor but without glucose. It was shown that livers perfused with 5 mM sensor but no glucose can detect glucose exported from hepatocytes after hormonal stimulation of glycogenolysis. CEST images of livers perfused in the magnet responded to changes in glucose concentrations demonstrating that the method has potential for imaging the tissue distribution of glucose in vivo. Magn Reson Med 60:1047–1055, 2008. © 2008 Wiley‐Liss, Inc.
Fiber tracking of human brain using fourth‐order tensor and high angular resolution diffusion imaging
Authors: Jayachandra M.R. , Rehbein N. , Herweh C. , Heiland S. 
Published: October 2008

AbstractThe accuracy of fiber tracking on the basis of diffusion tensor magnetic resonance imaging (DTI) is affected by many parameters. To increase accuracy of the tracking algorithm, we introduce DTI with a fourth‐order tensor. Tensor elements comprise information obtained by high angular resolution diffusion imaging (HARDI). We further developed the flattened high rank tensor (FLAHRT) method and applied it to the measured fourth‐order tensor. We then compared FLAHRT with: 1) the standard tracking algorithm using a second‐order tensor; and 2) existing techniques involving the representation of conventional second‐order tensor components as a weighted average of fourth‐order tensor elements. Such techniques have been formulated in recent DT studies to link high‐rank to low‐rank Cartesian diffusion tensors (DTs). Diagonalization of the second‐order tensor decomposes the tensor into three eigenvalues and three eigenvectors, which in turn are used to describe the diffusivity profile of a particular voxel. Diagonalization after application of the FLAHRT method reveals six eigenvalues and six eigentensors, resulting in a more accurate description of the anisotropy. We performed fiber tracking based on the eigenvalues and eigentensors calculated with the FLAHRT and standard methods. We could show that the FLAHRT technique gives more consistent and more accurate results even with a data set acquired in 15 directions only. The decomposition of the fourth‐order tensor into six eigentensors has the potential to describe six different fiber orientations within a voxel. Magn Reson Med 60:1207–1217, 2008. © 2008 Wiley‐Liss, Inc.
Dual Simulated Childbirth Injuries Result in Slowed Recovery of Pudendal Nerve and Urethral Function
Authors: Jiang Hai‐Hong , Pan Hui Q. , Gustilo‐Ashby Marcus A. , Gill Bradley , Glaab Jonathan , Zaszczurynski Paul , Damaser Margot 
Published: October 2008

AbstractAimsPelvic floor muscle trauma and pudendal nerve injury have been implicated in stress urinary incontinence (SUI) development after childbirth. In this study, we investigated how combinations of these injuries affect recovery.MethodsSixty‐seven female Sprague‐Dawley rats underwent vaginal distension (VD), pudendal nerve crush (PNC), PNC and VD (PNC + VD), pudendal nerve transection (PNT), or served as unmanipulated controls. Four days, 3 weeks, or 6 weeks after injury, we simultaneously recorded pudendal nerve motor branch potentials (PNMBP), external urethral sphincter electromyography (EUS EMG), and transurethral bladder pressure under urethane anesthesia. The presence of a guarding reflex (increased frequency and amplitude of PNMBP or EUS EMG activity) during leak point pressure (LPP) testing was determined.ResultsControls consistently demonstrated a guarding reflex. Four days after VD, EUS EMG activity was eliminated, but PNMBP activity reflected the guarding reflex; EUS EMG activity recovered after 3 weeks. Four days after PNC, both EUS EMG and PNMBP activity were eliminated, but demonstrated significant recovery at 3 weeks. Four days after PNC + VD both EUS EMG and nerve activity were eliminated, and little recovery was observed after 3 weeks with significant recovery of the guarding reflex 6 weeks after injury. Little recovery was observed at all time points after PNT. LPP results mirrored the reduction in EUS EMG activity.ConclusionFunctional recovery occurs more slowly after PNC + VD than after either PNC or VD alone. Future work will be aimed at testing methods to facilitate neuroregeneration and recovery after this clinically relevant dual injury. Neurourol. Urodynam. 28:229–235, 2009. © 2008 Wiley‐Liss, Inc.
Analysis of the stator/rotor‐contact in a two stators hybrid transducer type ultrasonic motor
Authors: Weerayuth Nantawatana , Seemann Wolfgang 
Published: October 2008

AbstractThis paper presents the procedure to understand the contact mechanism of the hybrid transducer type piezoelectric ultrasonic motor with two stators by using finite element analysis. First, the vibration mode of a stator will be calculated and analyzed using the commercial finite element program package ANSYS. The computed resonance frequencies of the stator will be presented in the frequency domain, in term of input admittance analysis. After that the distribution of the elliptic path of motion of a particle on the stator surface area will be studied. Finally, the contact condition between the stator and the rotor will be addressed in the computation. The normal displacement, normal velocity and tangential velocity of a point on stator surface area will be calculated. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Geometrical shape comparison by size theory
Authors: Frosini Patrizio 
Published: October 2008

AbstractSize Theory allows us to compare shapes of topological spaces and manifolds with respect to properties described by real functions. The main tools used in Size Theory are some pseudo‐distances measuring the minimal changes of these real functions under the action of homeomorphisms. This method can be adapted to several different definitions of shape without changing its geometrical‐topological framework. Some new results about this approach to shape comparison are illustrated. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Fast numerical solution of Boltzmann equation
Authors: Ibraghimov Ilghiz 
Published: October 2008

AbstractIn this work a new method is proposed for the solution of a spatially inhomogeneous Boltzmann equation. The key idea is to approximate the velocity space with multilinear tensors. This approach allows to solve huge numerical challenges with millions of space discretisations with the complexity of Navies‐Stocks solvers. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
On inverse crack problems in elastostatics
Authors: Ikehata Masaru , Itou Hiromichi 
Published: October 2008

AbstractIn solid mechanics, nondestructive testing has been an important technique in gathering information about unknown cracks, or defects in material. From a mathematical point of view, this is described as an inverse problem of partial differential equations, that is, the problem is to extract information about the location and shape of an unknown crack from the surface displacement field and traction on the boundary of the elastic material. By using the enclosure method introduced by Prof. Ikehata we can derive the extraction formula of an unknown linear crack from a single set of measured boundary data. Then, we need to have precise properties of a solution of the corresponding boundary value problem; for instance, an expansion formula around the crack tip. In this paper we consider the inverse problem concentrating on this point. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A preliminary study of the effect of the external stream structure on turbulent spots generation during by‐pass transition
Authors: Jonáš Pavel , Elsner Witold , Mazur Oton , Uruba Václav , Wysocki Marian 
Published: October 2008

AbstractThe investigation of turbulent spots production rate and average length at various FST turbulence length scales is worked on both the Narasimha's concept of the intermittency and the wavelet transform. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Doubly nonlinear evolution equations with non‐monotone perturbations
Authors: Akagi Goro 
Published: October 2008

AbstractThe local (in time) existence of strong solutions to Cauchy problems for doubly nonlinear abstract evolution equations with non‐monotone perturbations in reflexive Banach spaces is proved under appropriate assumptions, which allow the case where solutions of the corresponding unperturbed problem may not be unique. To prove the existence, a couple of approximate problems are introduced and delicate limiting procedures are discussed by using various tools from convex analysis and the Kakutani‐Ky Fan fixed point theorem. Furthermore, an application of the preceding abstract theory to a nonlinear PDE is also given. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Numerical simulation of thermal hydraulics in an ADSS model
Authors: Prakash K. Arul , Kumar B. V. Rathish , Biswas G. 
Published: October 2008

AbstractAccelerator Driven Sub‐critical nuclear reactor Systems (ADSS) are envisaged to enhance neutronics of reactors as well as safety physics. The spallation target module is the most innovative and key component for an ADSS. A conjugate heat transfer analysis is accomplished to mimic the physical operating condition of an ADSS in a more realistic way. The conduction equation of the beam window is solved in conjunction with the energy equation using the paradigm of domain decomposition parallelization method and the temperature distribution along the beam window is found. Finally, the thermal and mechanical stresses along the radial direction on the beam window is determined using temperature and pressure values. The stress values are found to increase with increasing Reynolds number (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Two main utility‐sharing methods in joint businesses: A discussion
Authors: Amer Rafel , Carreras Francesc , Magaña Antonio 
Published: October 2008

AbstractWe compare two methods of sharing costs or profits among agents in cooperative games: the well–known proportional rule and the Shapley value. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
An adaptive level set method for shock‐driven fluid‐structure interaction
Authors: Deiterding Ralf 
Published: October 2008

AbstractThe fluid‐structure interaction simulation of shock‐ and detonation‐loaded structures requires numerical methods that can cope with large deformations as well as local topology changes. A robust, level‐set‐based shock‐capturing fluid solver is described that allows coupling to any solid mechanics solver. As computational example, the elastic response of a thin steel panel, modeled with both shell and beam theory, to a shock wave in air is considered. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Deformation of bilayer lipid membranes in bio‐inspired materials and systems
Authors: Vita Raffaella De , Stewart Iain W. , Leo Donald J. 
Published: October 2008

AbstractPlanar bilayer lipid membranes (BLMs) are currently employed to construct many bio‐inspired material systems and structures. In order to characterize the pressure effects on the equilibrium configurations of these biological membranes, a novel continuum model is proposed. The BLM is assumed to be a two‐layer Smectic A liquid crystal. The mean orientation of the amphiphilic molecules comprising the membrane is postulated to be perpendicular to the layers and each layer is idealized as a two dimensional liquid. Moreover, the BLM is modeled as a simply supported plate undergoing small deformations. It is subjected to a pressure load that acts perpendicularly to the layers. The equilibrium equations and boundary conditions are derived from the bulk elastic energy for Smectic A liquid crystals as described by de Gennes and Prost (1993) by using variational methods. The resulting fourth‐order linear partial differential equation is solved by employing cylindrical functions and the series solution is proved to be convergent. The solution is numerically computed for values of the model parameters that are reported in the literature. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Hammering of gear wheels
Authors: Eberhard Peter , Ziegler Pascal 
Published: October 2008

AbstractThe dynamic behavior of gear trains is very often dominated by a rattling motion of teeth within the backlash. Because of the excited noise it is often referred to as gear hammering. It mainly originates from high dynamic loads of gas forces and auxiliary devices that usually exceed the nominal torque by far. Of course, the knowledge of the resulting contact forces is very important for the design. Since measurement of contact forces is complicated and expensive, the precise simulation of contact forces and the arising dynamic behavior of the complete gear trains is very important. Typically, gear wheels are modelled as rigid bodies, coupled by spring‐damper combinations. In this paper we show that this assumption may not hold for impact‐like contacts as they often occur in gear trains and may even be wrong for very compliant gear bodies as they are often used in gear trains. We present very detailed finite element analyses for impacts in a gear pair of a real gear train and compare the results to a rigid body model. The differences emerge from dynamic gear body effects, and an elastic description of the gear wheels is necessary to precisely simulate gear forces. In order to be able to use a fully elastic approach to simulate the contacts between gear wheels, a modal approach with a collision detection and a local force description is used. This approach allows simulations nearly as precise as finite element simulations but with a simulation time of more than a factor 1000 faster. This allows the transient simulation of many contacts and many rotations using a fully elastic model. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Numerical approximation of solutions to nonlinear inverse problems arising in olfaction experimentation
Authors: French D.A. , Kleene S.J. 
Published: October 2008

AbstractIdentification of detailed features of neuronal systems is an important challenge in the biosciences today. An interdisciplinary research team has been working to determine the distributions of ligand gated ion channels in frog olfactory cilia which are long thin processes that extend from the olfactory receptor neurons. Experiments involving ligand diffusion are performed leading to current data dependent on time. Mathematical models of the experiment are derived and solved numerically to obtain estimates of the spatial distributions of the ion channels along the length of a cilium from the data. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Singular elliptic and parabolic problems and a class of free boundary problems
Authors: Guidotti Patrick 
Published: October 2008

AbstractIn this short contribution we report on some recently made progress in the analytical treatment of a class of Free Boundary Problems (FBPs) characterized by the initial onset of a phase. The analysis is motivated by a model problem arising in the description of case II diffusion in polymers. The main local well‐posedness and regularity theorem is obtained by means of fundamental results concerning the underlying singular elliptic and parabolic boundary value problems. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Resonance in viscous film flow over topography
Authors: Heining Christian , Wierschem Andreas , Bontozoglou Vasilis , Aksel Nuri , Uecker Hannes 
Published: October 2008

AbstractWe study viscous gravity‐driven films flowing over periodically undulated substrates. Linear analysis describes resonance in steady flow along small bottom corrugations for films of arbitrary thickness. Depending on the dimensionless film thickness we find different regimes for the resonance, which is associated with the interaction of the undulated film with capillary‐gravity waves traveling against the flow. Nonlinear terms produce higher harmonics resonance which in particular may lead to bistable resonance similar to that of the driven Duffing oscillator. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Selection of steady states in planar Darcy convection
Authors: Karasözen B. , Tsybulin V. G. 
Published: October 2008

AbstractThe planar natural convection of incompressible fluid in a porous medium is considered. We study selection of steady states under temperature perturbations on the boundary. A selection map is introduced to analyze the selection of steady state from a continuous family of equilibria which exists under zero boundary conditions. The results of finite‐difference modeling for the rectangular enclosure are presented. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The Euler‐Maupertuis principle of least action as variational inequality
Authors: Leine R. I. , Aeberhard U. 
Published: October 2008

AbstractStarting from Hamilton's Principle, the current paper discusses how we can derive the Euler‐Maupertuis Principle of Least Action in the context of non‐smooth dynamics. This variational principle allows us to directly obtain the space curve y (x) of a point‐mass in a potential field V (x, y) without referring to the temporal dynamics. This paper generalises the Euler‐Maupertuis Principle of Least Action to systems with impact by formulating the principle as a variational inequality. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A fully‐coupled nonlinear thermoelectromechanical model for piezolaminated smart structures
Authors: Lentzen Sven , Schmidt Rüdiger 
Published: October 2008

AbstractIn present engineering applications piezoelectric materials gain increasing importance in the development of smart structures; e.g., for shape and vibration control problems. Such structures exhibit a three‐way coupling effect between the mechanical, electrical and thermal quantities. In the majority of papers available in literature this coupling is taken into account only in the constitutive equations. It is however well known that truly coupled analysis should also be based on the interaction of the mechanical, thermal and electrostatic quantities in the field equations. Only in this way many physical effects can be taken into account; e.g., the strain rate dependant change of temperature due to mechanical loading. Furthermore most of the analyses conducted in this area are performed in the linear range of deformations assuming small strains, rotations and temperature changes. However smart technology is generally applied to thin walled structures and in many cases reported in literature the deflections are much larger than the thickness, which results into geometrically nonlinear behaviour, like e.g. the occurrence of stress stiffening which greatly affects the prediction of sensor voltage outputs. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
An approach to different voting rules from cooperative games with alternatives. Case study: the Catalonia Parliament
Authors: Carreras Francesc , Magaña Antonio 
Published: October 2008

AbstractWe apply simple games with alternatives to describe voting mechanisms used in parliamentary organizations. As a matter of example, we analyze the Catalonia Parliament. Special attention is paid to abstention, which is allowed in most voting rules but is not taken into account when a voting rule is modelled as a simple classical game. To measure the power of each voter in each game, the extended Shapley–Shubik index is considered. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Comparison of parallel eigensolvers for a discretized radiative transfer problem
Authors: Vasconcelos P. B. , Marques O. A. 
Published: October 2008

AbstractIn this work we consider the numerical computation of eigenpairs of integral operators associated to a radiative transfer problem. The target problem models the emission of photons in stellar atmospheres and is formulated in terms of a weakly singular Fredholm integral equation defined on a Banach space. We examine parallel, direct and iterative strategies for the eigensolution phase. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Shock‐capturing schemes: high accuracy versus total‐variation boundedness
Authors: Marquina Antonio , Serna Susana 
Published: October 2008

AbstractIn this reseach work we analyze the total variation growth of some high order accurate reconstruction procedures used for the design of shock capturing schemes. This study allows to measure how oscillatory a high order accurate method is in terms of the basic elementary function chosen to increase the order of accuracy. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)