bluuebunny/crossref_metadata_2025_split huggingface dataset:
A variational approach to optimal control problems for elastic body motions
Authors: Kostin G. , Saurin V. 
Published: August 2008

AbstractThe initial‐boundary problem for the linear theory of elasticity is considered. Based on the method of integrodifferential relations a new dynamical variational principle in which displacement, stress, and momentum functions are varied is proposed and discussed. To minimize the nonnegative functional under initial, boundary, and partial differential constraints arising in this approach a regular algorithm for approximation of the unknown functions is worked out. The algorithm gives us the possibility to estimate explicitly the local and integral quality of obtained numerical solutions. An effective numerical method for the optimization problems of controlled motions of elastic bodies with quadratic objective functionals is developed. As example, the 3D problems of optimal longitudinal motions of a rectilinear elastic prism with a quadratic cross section are considered for the terminal total mechanical energy to be minimized. The numerical results and their error estimates are presented and discussed. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
An application of parabolic H‐measures
Authors: Antonić Nenad , Lazar Martin 
Published: August 2008

AbstractA new, parabolic variant of H‐measures, as well as its application to the advection‐diffusion equation is presented. By the means of localisation property, the strong compactness for gradients of solutions is obtained in the case of variable coefficients. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
DNA supercoiling modeling of nucleosome and viral spooling
Authors: Maggioni Francesca , Ricca Renzo L. 
Published: August 2008

AbstractNew kinematic equations are used to model DNA supercoiling. These equations govern the simultaneous production of multiple folding and coiling of a filament in space by diffeomorphism of a reference curve. Here we show how to use these equations to model regions of highly localized filament coiling, where mechanisms of proteic coding or viral spooling are important. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
On the interconnection structures of discretized port Hamiltonian systems
Authors: Eberard D. , Maschke B.M. , van der Schaft A.J. 
Published: August 2008

AbstractFor numerical simulation and control design purposes, a mixed‐finite element method [3] preserving the port Hamiltonian structure of the system has been developed [2]. This method was successfully applied for 1D systems. In this paper, we shall suggest some generalization of this result to higher dimensional spatial domain (3D) using Whitney forms as Galerkin base. The discretization procedure is illustrated on Maxwell's equations. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Verifying all eigenpairs in symmetric positive definite generalized eigenvalue problem
Authors: Miyajima Shinya , Ogita Takeshi , Oishi Shin'ichi 
Published: August 2008

AbstractA fast method for enclosing all eigenpairs in symmetric positive definite generalized eigenvalue problem is proposed. Firstly theorems on verifying all eigenvalues are presented. Next a theorem on verifying all eigenvectors is presented. The proposed method is developed based on these theorems. Numerical results are presented showing the efficiency of the proposed method. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Fractional amplitude and phase dynamics in super‐diffusive reaction–diffusion systems
Authors: Nec Y. , Nepomnyashchy A.A. , Golovin A.A. 
Published: August 2008

AbstractStudy of weakly non‐linear dynamics of a reaction–super‐diffusion system near a Hopf bifurcation by means of fractional analogues of complex Ginzburg‐Landau and Kuramoto‐Sivashinsky equations is presented. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Error estimates for an Euler implicit‐mixed finite element scheme for reactive transport in saturated/unsaturated soil
Authors: Radu Florin A. , Pop Iuliu S. , Attinger Sabine , Knabner Peter 
Published: August 2008

AbstractWe present convergence results for a fully discrete scheme based on the mixed finite element (MFE) method and an one‐step Euler implicit (EI) method for simulating reactive solute transport in saturated/unsaturated soil. The results considered the low regularity of the solution of the degenerate parabolic equation describing the water flow in porous media. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Modelling of tear propagation in soft hydrated biological tissue
Authors: Rempler Hans‐Uwe , Ehlers Wolfgang 
Published: August 2008

AbstractWe present a method for the numerical simulation of tear propagations in soft hydrated biological tissues. The tissue is modelled using the Theory of Porous Media (TPM) which allows the description of multi‐component continua with internal interaction. For the numerical treatment of the tearing mechanism, the Extended Finite Element Method (XFEM) is applied. Discontinuities resulting from the tearing are numerically described by a vector level‐set function. Volume changes due to the tear propagation are taken into account with a formulation of internal fluid flow towards the additional volume. Therein, fluid flow is regarded as an internal Neumann boundary. A numerical example shows the pressure development and fluid flow during a mode 1 tearing experiment. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A mixed finite element formulation for piezoelectric shells
Authors: Schulz Katrin , Klinkel Sven 
Published: August 2008

AbstractA finite element formulation to analyze piezoelectric shell problems is presented. A reference surface of the shell is modelled with a four node element. Each node possesses six mechanical degrees of freedom, three displacements and three rotations, and one electric degree of freedom, which is the difference of the electric potential in thickness direction. The formulation is based on the mixed field variational principle of Hu‐Washizu. The independent fields are displacements u, electric potential φ, strains E, electric field E, stresses S and dielectric displacements D. The mixed formulation allows an interpolation of the strains and the electric field in thickness direction. Accordingly a three‐dimensional material law is incorporated in the variational formulation. It is remarked that no simplification regarding the constitutive law is assumed. The formulation allows the consideration of arbitrary constitutive relations. The normal zero stress condition and the normal zero dielectric displacement condition are enforced by the independent stress and dielectric displacement fields. They are defined as zero in thickness direction. The present shell element fulfills the important patch tests: the in‐plane, bending and shear test. Some numerical examples demonstrate the applicability of the present piezoelectric shell element. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Accelerating the coarse time‐stepper for a lattice Boltzmann model
Authors: Vandekerckhove Christophe , Roose Dirk 
Published: August 2008

AbstractThe equation‐free framework for multiscale computing is built around the central idea of a coarse time‐stepper, which is an approximate time integrator for the macroscopic variables when only a microscopic simulator is available. In a previous paper, we studied the accuracy and stability of the coarse time‐stepper when the microscopic simulator is a lattice Boltzmann model for one‐dimensional diffusion. In this paper, we rely on these results to show how the coarse time‐stepper can be accelerated using the recently proposed teleprojective method or the multistep state extrapolation method. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A variational formulation of nonlocalmaterials withmicrostructure based on dual macro‐ and micro‐balances
Authors: Welschinger Fabian , Zimmermann Dominik , Miehe Christian 
Published: August 2008

AbstractWe investigate a variational setting of nonlocal materials with microstructure and outline aspects of its numerical implementation. Thereby, the current state of the evolving microstructure is described by independent global degrees in addition to the macroscopic displacement field, so‐called order parameters. Focussing on standard‐dissipative materials, the constitutive response is governed by two fundamental functions for the energy storage and the dissipation. Based on these functions, a global dissipation postulate is introduced. Its exploitation constitutes a global variation formulation of nonlocal materials, which can be related to a minimization principle. Following this methodology, we end up with coupled macro‐ and microscopic field equations and corresponding boundary conditions. On the numerical side, we consider the weak counterpart of these coupled field equations and obtain after linearization a fully coupled system for increments of the displacement and the order parameters. Due to the underlying variational structure, this system of equations is symmetric. In order to show the capability of the proposed setting, we specify the above outlined scenario to a model problem of isotropic damage mechanics. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
DNS of laminar separation nubble flows with free‐stream fluctuations
Authors: Wissink Jan G. , Rodi Wolfgang 
Published: August 2008

AbstractA series of Direct Numerical Simulations (DNS) of Laminar Separation Bubble (LSB) flow in the presence of external disturbances has been performed. In all simulations, the primary mechanism for the transition to turbulence was found to be a two‐dimensional Kelvin‐Helmholtz (KH) instability of the separated shear layer that was triggered by the external fluctuation(s). The KH instability caused the shear layer to roll up. Inside the rolled up shear layer, entrained disturbances triggered elliptic instabilities which led to a rapid transition to fully three‐dimensional (3D) turbulence. In the simulations with inflow oscillations the streamwise variation of the location of transition was found to decrease with the amplitude of the inflow oscillation. In the simulations with free‐stream turbulence the size of the separation bubble – measured by the shape factor – was found to drastically decrease with increasing free‐stream turbulence level. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Synthesis and properties of new derivatives of poly[9‐(2,3‐epoxypropyl)carbazole]
Authors: Malinauskas Tadas , Vilionskiene Ingrida , Grazulevicius Juozas V , Getautis Vytautas , Reina Jose A , Sidaravicius Jonas 
Published: August 2008

AbstractBACKGROUND: Carbazole derivatives are well known to exhibit interesting electro‐ and photo‐active properties due to their hole‐transporting ability, strong absorption in the ultraviolet spectral region and blue‐light emission. One of the most widely studied materials among carbazole‐containing oligomers is poly[9‐(2,3‐epoxypropyl)carbazole] (PEPK). The main field of application of this oligomer is electrophotographic microfilming. It is also used for the manufacture of multicolour slides and in the photothermoplastic recording of information. Unfortunately, due to its high ionization potential, which reaches 5.86 eV, the possibilities of application of this compound in optoelectronic devices are rather limited.RESULTS: PEPK‐based charge transporting oligomers, incorporating hydrazone moieties, are reported. The oligomers were prepared by chemical modification of PEPK. The materials obtained were examined using various techniques including differential scanning calorimetry and ultraviolet, infrared and NMR spectroscopy. Electron photoemission spectra of layers of the synthesized oligomers showed ionization potentials (Ip) in the range 5.4–5.5 eV.CONCLUSION: The synthesized oligomers possess a larger π‐conjugated system and show ionization potentials of ca 5.4 eV. Therefore, they are more suitable for use in optoelectronic devices with quicker photoresponse than unmodified PEPK. Copyright © 2008 Society of Chemical Industry
Nonionic detergent phase extraction for the proteomic analysis of heart membrane proteins using label‐free LC‐MS
Authors: Donoghue Pamela M. , Hughes Chris , Vissers Johannes P. C. , Langridge James I. , Dunn Michael J. 
Published: August 2008

AbstractHeart diseases resulting in heart failure are among the leading causes of morbidity and mortality in the Western world and can result from either systemic disease (e.g., hypertensive heart disease, ischemic heart disease) or specific heart muscle disease (e.g., dilated cardiomyopathy/DCM). Subproteome analysis of such disease subsets affords a reduction in sample complexity, potentially revealing biomarkers of cardiac failure that would otherwise remain undiscovered in proteome wide studies. Label‐free nanoscale LC‐MS has been applied in this study to validate a Triton X‐114‐based phase enrichment method for cardiac membrane proteins. Annotation of the subcellular location combined with GRAVY score analysis indicates a clear separation between soluble and membrane‐bound proteins with an enrichment of over 62% for this protein subset. LC‐MS allowed confident identification and annotation of hydrophobic proteins in this control sample pilot study and demonstrates the power of the proposed technique to extract integral membrane‐bound proteins. This approach should be applicable to a wider scale study of disease‐associated changes in the cardiac membrane subproteome.
Adapting the stretched sample method from tissue profiling to imaging
Authors: Zimmerman Tyler A. , Monroe Eric B. , Sweedler Jonathan V. 
Published: August 2008

AbstractThe characterization and localization of peptides and proteins in tissues provides information that aids in understanding their function and in characterizing disease states. Over the past decades, the use of MS for the profiling and imaging of biological compounds from tissues has evolved into a powerful modality to accomplish these studies. One recently described sampling approach, the stretched sample method (Monroe, E. B. et al.., Anal. Chem. 2006, 78, 6826–6832), places a tissue section onto an array of glass beads embedded on a Parafilm M membrane. When the membrane is stretched, it separates the tissue section into thousands of cell‐sized pieces for tissue profiling by MALDI‐MS. The physical separation between beads eliminates analyte redistribution during matrix application and allows long analyte extraction periods without loss of spatial resolution. Here, we enhance this sampling approach by introducing algorithms that enable the reconstruction of ion images from these stretched samples. As the first step, a sample‐tailored data acquisition method is devised to obtain mass spectra exclusively from the beads, thereby reducing the time, instrument resources, and data handling required for such MS imaging (MSI) experiments. Next, an image reconstruction algorithm matches data acquired from the stretched sample to the initial bead locations. The efficacy of this method is demonstrated using peptide‐coated beads with known peptide distributions and appears well‐suited to the MSI of heterogeneous tissue samples.
Effect of Plasma Exposure on the Chemistry and Morphology of Aerosol‐Assisted, Plasma‐Deposited Coatings
Authors: Twomey Barry , Rahman Mahfujur , Byrne Gerry , Hynes Alan , O'Hare Lesley‐Ann , O'Neill Liam , Dowling Denis 
Published: August 2008

AbstractThis study reports on the effect on the morphology and chemistry of atmospheric pressure plasma deposited nm‐thick coatings (21 ± 3 nm) as the level of exposure to the plasma is systematically altered. Coatings were deposited by directly injecting hexamethyldisiloxane, polydimethylsiloxane or tetramethyldisiloxane liquid precursors through a nebulizer into a helium/oxygen atmospheric pressure plasma. An increase in the level of the precursor was found to be associated with a decrease in the concentration of methyl functional groups in the coating and to an increase of the SiO crosslinking, as demonstrated using surface energy and XPS analysis. This resulted in an increase in the coating refractive index, and in a reduction of the number of surface particulates, as well as of surface roughness.magnified image
Unmethylated E‐Cadherin gene expression is significantly associated with metastatic human prostate cancer cells in bone
Authors: Saha Baisakhi , Kaur Pavinder , Tsao‐Wei Denice , Naritoku Wesley Y. , Groshen Susan , Datar Ram H. , Jones Lawrence W. , Imam S. Ashraf 
Published: August 2008

AbstractBACKGROUNDThe concurrent determination of methylation status of E‐cadherin gene and E‐cadherin protein expression remains scant in metastatic prostate cancer cells in bone, the most prevalent site for metastatic growth. Therefore, the study was undertaken to ascertain the methylation status of E‐cadherin gene, a most frequent and known epigenetic mechanism of its regulation, and the protein expression in prostate tissue biopsy specimen.METHODSThe methylation of E‐cadherin gene was determined by methylation specific‐PCR and the protein expression by immunohistochemical method in the consecutive sections of each prostate tissue biopsy specimen.RESULTSThe unmethylated E‐cadherin gene and homogeneous E‐cadherin protein expression was significantly associated with BPH as compared to the primary prostate carcinoma (Fisher's Exact P < 0.001). A significant association was observed between the concurrent methylated gene and markedly reduced expression of the protein in the primary prostate cancer cells as compared to the BPH cells, suggesting methylation‐dependent regulation of the gene expression in these cases. In contrast to the primary cancer, a highly significant increase in the frequency of metastatic prostate cancer cells in bone exhibited the concurrent expression of unmethylated gene and homogeneous protein (Fisher's Exact P < 0.001).CONCLUSIONSThe study clearly demonstrated a significant association of the concurrent expression of unmethylated E‐cadherin gene and E‐cadherin protein with metastatic prostate cancer cells in bone, and that its expression may have a role in the intercellular adhesion in the formation of metastatic lesions in bone. Prostate 68: 1681–1688, 2008. © 2008 Wiley‐Liss, Inc.
Neonicotinoids—from zero to hero in insecticide chemistry
Authors: Jeschke Peter , Nauen Ralf 
Published: August 2008

AbstractIn recent years, neonicotinoids have been the fastest‐growing class of insecticides in modern crop protection, with widespread use against a broad spectrum of sucking and certain chewing pests. As potent agonists, they act selectively on insect nicotinic acetylcholine receptors, their molecular target site. The discovery of neonicotinoids can be considered as a milestone in insecticide research and facilitates greatly the understanding of the functional properties of insect nicotinic acetylcholine receptors. Because of the relatively low risk for non‐target organisms and environment, the high target specificity of neonicotinoid insecticides and their versatility in application methods, this important class has to be maintained globally for integrated pest management strategies and insect resistance management programmes. This review comprehensively describes particularly the origin, structure and bonding as well as associated properties of neonicotinoid insecticides. Copyright © 2008 Society of Chemical Industry
Is thermal conductivity time‐dependent?
Authors: Hüttner Bernd 
Published: August 2008

AbstractThe question whether thermal conductivity may be time dependent on short time scales is investigated and answered in the affirmative. For this purpose, we make use of a classical relation between the Brownian mean displacement and the thermal conductivity. Interestingly, the transition from the time dependent regime to stationary behaviour is in the vicinity of Allen's temperature relaxation time. Calculation of the electronic temperature, when the new time dependent thermal conductivity is used, shows an improvement in the results derived by means of the two‐temperature model. Furthermore, the Wiedemann–Franz law is not valid in the time regime investigated. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Semiconducting P3HT microstructures: fibres and tubes obtained from macroporous silicon template
Authors: Palacios R. , Formentín P. , Trifonov T. , Estrada M. , Alcubilla R. , Pallarés J. , Marsal L. F. 
Published: August 2008

AbstractMicrotubes and microfibres composed of poly(3‐hexylthiophene) (P3HT) were fabricated by melt‐assisted templates using ordered macroporous silicon. We have studied the influence of the pore depth and the template type on the microstructure fabrication, where the templates were membranes or structures opened only at one end. Current– voltage (I–V) measurements demostrated that the resistivity of these P3HT microstructures was in the same order as that of homogeneous films, which allows them to be used in electronic devices. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A Combined Virtual Screening 2D and 3D QSAR Methodology for the Selection of New Anticonvulsant Candidates from a Natural Product Library
Authors: Gavernet Luciana , Talevi Alan , Castro Eduardo A. , Bruno‐Blanch Luis E. 
Published: August 2008

AbstractA virtual screening methodology combining a discriminant function (df) based on Dragon 2D‐descriptors, general ADME filters, and a pharmacophore identified through superposition of rigid analogs was applied in order to identify new anticonvulsant agents among 10 903 natural products. Fifty‐six compounds were selected from the application of this df, Lipinski's rule‐of‐five and other criteria for prediction of oral bioavailability, and the optimal value of log P for a compound to diffuse passively through the blood–brain barrier. Seven of these compounds were removed because they did not belong to descriptor space defined by the training set. The remaining 49 compounds were fitted to the pharmacophore structural constrains, selecting 7 structures with RMS distance value below 0.2. Systematic conformational analysis was performed to find the global minimum conformation, using the PM3 base included in Hyperchem 6.03. The global minimum conformations were further refined at a 6‐31G** level with Gaussian 03. Restricted optimization was then performed to determine the energy difference between the energy minimum conformation and the active conformation defined by the pharmacophore, retaining those structures whose energy differences were below 7 kcal/mol. Four new potential anticonvulsants which fulfill the df and the pharmacophore requisites were selected. One of these structures, 2‐(4,6‐dimethyl‐1‐benzofuran‐3‐yl)acetic acid, was acquired and assayed in the MES and Rotorod tests, confirming anticonvulsant activity in mice at 30 and 100 mg/kg (0.5 and 4 h, i.p.) and absence of neurotoxicity at the tested doses.