bluuebunny/crossref_metadata_2025_split huggingface dataset:
Pair distribution function and pair potential of lattice model chains under theta conditions, 2. Theoretical approach
Authors: Olaj Oskar Friedrich 
Published: February 2006

AbstractA general expression for the pair potential U and the pair distribution function G for an isolated pair of coiled unbranched macromolecules is derived with special reference to the Θ‐state, using a sort of “square well” potential for the description of segment‐segment interaction. Contrary to former treatments allowance has been made for the fact that at least those segment‐segment interactions which are not of hard sphere character occur at a finite contact distance δ. The “contact sites”, i.e. the locations which–in order to produce this type of interaction–have to be occupied by segments of the second chain of the pair, are shown to obey a broader distribution around the center of gravity of the first chain than its segments themselves. As a consequence the hard sphere (repulsive) and the non‐hard sphere (for the Θ‐state necessarily attractive) interactions between the two chains show a different dependence on the distance R between the centers of mass of the two chains, leading to expressions for U and G—well consistent with numerical Monte Carlo estimates‐which have the general form

and

respectively, with a always exceeding a′ and for the Θ‐state A>A′. All these parameters are well defined in terms of the model used.
Processing and classification of protein mass spectra
Authors: Hilario Melanie , Kalousis Alexandros , Pellegrini Christian , Müller Markus 
Published: February 2006

AbstractAmong the many applications of mass spectrometry, biomarker pattern discovery from protein mass spectra has aroused considerable interest in the past few years. While research efforts have raised hopes of early and less invasive diagnosis, they have also brought to light the many issues to be tackled before mass‐spectra‐based proteomic patterns become routine clinical tools. Known issues cover the entire pipeline leading from sample collection through mass spectrometry analytics to biomarker pattern extraction, validation, and interpretation. This study focuses on the data‐analytical phase, which takes as input mass spectra of biological specimens and discovers patterns of peak masses and intensities that discriminate between different pathological states. We survey current work and investigate computational issues concerning the different stages of the knowledge discovery process: exploratory analysis, quality control, and diverse transforms of mass spectra, followed by further dimensionality reduction, classification, and model evaluation. We conclude after a brief discussion of the critical biomedical task of analyzing discovered discriminatory patterns to identify their component proteins as well as interpret and validate their biological implications. © 2006 Wiley Periodicals, Inc., Mass Spec Rev 25:409–449, 2006
Mass spectrometry and natural variations of iron isotopes
Authors: Dauphas Nicolas , Rouxel Olivier 
Published: February 2006

AbstractAn Erratum has been published for this article in Mass Spectrometry Reviews 25: 831–832, 2006.Although the processes that govern iron isotope variations in nature are just beginning to be understood, multiple studies attest of the virtue of this system to solve important problems in geosciences and biology. In this article, we review recent advances in the geochemistry, cosmochemistry, and biochemistry of iron isotopes. In Section 2, we briefly address the question of the nucleosynthesis of Fe isotopes. In Section 3, we describe the different methods for purifying Fe and analyzing its isotopic composition. The methods of SIMS, RIMS, and TIMS are presented but more weight is given to measurements by MC‐ICPMS. In Section 4, the isotope anomalies measured in extraterrestrial material are briefly discussed. In Section 5, we show how high temperature processes like evaporation, condensation, diffusion, reduction, and phase partitioning can affect Fe isotopic composition. In Section 6, the various low temperature processes causing Fe isotopic fractionation are presented. These involve aqueous and biologic systems. © 2006 Wiley Periodicals, Inc., Mass Spec Rev 25:515–550, 2006
Investigation of molecular interaction within biological macromolecular complexes by mass spectrometry
Authors: Akashi Satoko 
Published: February 2006

AbstractThe advent of electrospray ionization (ESI) and matrix‐assisted laser desorption ionization (MALDI) has accelerated structural studies of biological macromolecular complexes. At present, mass spectrometry can provide accurate mass values not only of individual biological macromolecules but also of their assemblies. Furthermore, it can also give information on the interface sites of the biological macromolecular complexes. The present article focuses on the role of mass spectrometry in the investigation of biological molecular interactions, such as protein–protein, protein–DNA, and protein–ligand interactions, which play essential roles in various biological events. © 2006 Wiley Periodicals, Inc.
Scattering of elastic waves in a perturbed isotropic half space with a free boundary. The limiting absorption principle
Authors: Dermenjian Yves , Guillot Jean‐Claude 
Published: February 2006

AbstractIn this article we consider the self‐adjoint operator governing the propagation of elastic waves in a perturbed isotropic half space with a free boundary condition. We prove the limiting absorption principle in appropriate Hilbert spaces for this operator. We also prove decreasing properties for the eigenfunctions associated with strictly positive eigenvalues of this operator.The proofs are based on the limiting absorption principle for the self‐adjoint operator governing the propagation of elastic waves in a homogeneous isotropic half space with a free boundary and on the so called division theorem for it. Both perturbations of R+2 ={(x1, x2) ϵ R2; x2 > 0} and R+2 = {(x1, x2, x3) ϵ R3; x3 > 0} are considered.
Uniqueness for structural phase transitions in shape memory alloys
Authors: Hoffmann K.‐H. , Songmu Zheng 
Published: February 2006

AbstractThe non‐linear coupled equations arising from alloy mechanism

have two important features: a may take negative values and c may be degenerate.The local existence has been proved in Reference 1, but the uniqueness was open. In this paper the uniqueness is proved. For a discussion of the physical model and for the justifications of the detailed technical assumptions to be made, we refer to Reference 1.
The optimization of directivity and signal‐to‐noise ratio of an arbitrary antenna array
Authors: Kirsch Andreas , Wilde Peter , Roach G.F. 
Published: February 2006

AbstractThe authors consider the optimization of the signal‐to‐noise ratio of an arbitrary cylindrical antenna array. Existence of an optimal solution and convergence of finite‐dimensional approximations is shown. The necessary optimality conditions are used to compute optimal solutions for some numerical examples.
CFD state‐of‐the art in the U.S.S.R.
Authors: Belotserkovskii O. M. 
Published: February 2006

AbstractThis survey paper is devoted to the description of numerical methods for modern problems of computational fluid dynamics (CFD). The problems of steady and unsteady aerodynamic flows, different transition turbulent regimes and motion around complex shape bodies (aircraft as a whole) are investigated. These approaches sharply reduce the level of demand on computer resources.
Generation, optimization and adaptation of multiblock grids around complex configurations in computational fluid dynamics
Authors: Jacquotte Olivier‐Pierre 
Published: February 2006

AbstractWe present a method that has been developed for the construction of grids suitable for a large class of Computational Fluid Dynamics (CFD) solvers. Three independent steps are considered: a multidomain generation, an optimization and an adaptation. The first step handles the complexity of the three‐dimensional domain to be meshed and is able to perform an algebraic construction of the grid points within a multidomain topology; any decomposition can be considered and analysed by the algorithm. The second step is able to optimize a mesh with respect to a quality measure defined in terms of cell deformation; a conjugate gradient algorithm drives the nodes up to an equilibrium position that realizes the minimum of a mesh energy quantity. The final step handles the physics of the problem and moves the nodes in order to refine the mesh where anything of interest takes place, while preserving its good metric quality. The three steps have been implemented independently and successfully, as shown by the examples presented.
Time marching integral equation method for unsteady transonic flows around airfoils
Authors: Su Jicaho 
Published: February 2006

AbstractA time marching integral equation method has been proposed here which does not have the limitation of the time linearized integral equation method in that the latter method can not satisfactorily simulate the shock wave motions. Firstly, a model problem–one dimensional initial and boundary value wave problem is treated to clarify the basic idea of the new method. Then the method is implemented for two dimensional unsteady transonic flow problems. The introduction of the concept of a quasi‐velocity‐potential simplifies the time marching integral equations and the treatment of trailing vortex sheet condition. The numerical calculations show that the method is reasonable and reliable.
Numerical simulation of three‐dimensional supersonic flow around aerodynamic configurations
Authors: Chushkin P. I. , Voskresensky G. P. 
Published: February 2006

AbstractThe present report deals with many applications of different numerical methods to calculations of three‐dimensional stationary supersonic flows around aerodynamic configurations. Both an inviscid non‐heat‐conducting perfect gas and a real high‐temperature gas with physical‐chemical processes are considered. The results of some investigations carried out during recent years in the U.S.S.R. are reviewed. A brief description of applicable numerical methods is presented. A number of results are discussed both for separate parts of a flying vehicle and for whole configurations. Some gasdynamic effects, and aerodynamic and thermal characteristics are analysed. Among the aerodynamic elements we consider pointed and blunted nose parts of configurations, air intakes, wing and stabilizers. Also more complicated cases are considered such as compound aerodynamic objects and configurations modelling different kinds of whole flying vehicles (missile, aircraft, spacecraft).
Improving the convergence rate of the Petrov‐Galerkin techniques for the solution of transonic and supersonic flows
Authors: Baumann C. E. , Storti M. A. , Idelsohn S. R. 
Published: February 2006

AbstractThis paper report progress on a technique to accelerate the convergence to steady solutions when the streamline‐upwind/Petrov‐Galerkin (SUPG) technique is used. Both the description of a SUPG formulation and the documentation of the development of a code for the finite element solution of transonic and supersonic flows are reported. The aim of this work is to present a formulation to be able to treat domains of any configuration and to use the appropriate physical boundary conditions, which are the major stumbling blocks of the finite difference schemes, together with an appropriate convergence rate to the steady solution.The implemented code has the following features: the Hughes' SUPG‐type formulation with an oscillation‐free shock‐capturing operator, adaptive refinement, explicit integration with local time‐step and hourglassing control. An automatic scheme for dealing with slip boundary conditions and a boundary‐augmented lumped mass matrix for speeding up convergence.It is shown that the velocities at which the error is absorbed in and ejected from the domain (that is damping and group velocities respectively) are strongly affected by the time step used, and that damping gives an O(N2) algorithm contrasting with the O(N) one given by absorption at the boundaries. Nonetheless, the absorbing effect is very low when very different eigenvalues are present, such as in the transonic case, because the stability condition imposes a too slow group velocity for the smaller eigenvalues. To overcome this drawback we present a new mass matrix that provides us with a scheme having the highest group velocity attainable in all the components.In Section 1 we will describe briefly the theoretical background of the SUPG formulation. In Section 2 it is described how the foregoing formulation was used in the finite element code and which are the appropriate boundary conditions to be used. Finally in Section 3 we will show some results obtained with this code.
Numerical simulation of the gas flow in a circuit‐breaker
Authors: Reggio M. , Trépanier J. Y. , Zhang H. , Camarero R. 
Published: February 2006

AbstractA computational methodology for the solution of unsteady two‐dimensional/axisymmetric Euler equations within geometries with moving boundaries is presented. The flow simulation is carried out by applying a finite‐volume method which makes use of a Lagrangian‐Eulerian version of Roe's approximate Riemann solver. The domain discretization is handled via unstructured triangular grids. Grid adaptation is applied on the basis of geometric and physical requirements. The importance of the implicit treatment of the space conservation laws, based on geometric analysis, is evoked. The procedure for reconstructing Roe's method for moving meshes is described and validated. Finally, the ability of the method for the prediction of the transient flow in a circuit‐breaker during its opening phase is illustrated.
Transient natural convection from a horizontal cylinder confined between vertical walls—a finite element solution
Authors: Sadeghipour M. Sadegh , Hannani S. Kazemzadeh 
Published: February 2006

AbstractA general finite element computer code is developed for transient two dimensional natural convection heat transfer in a laminar regime. This code is used to study heat transfer from a horizontal isothermal cylinder confined between two vertical adiabatic walls. Results are presented for Ra = 1000, Pr = 0.7, and for different wall spacing to cylinder diameter ratios. The time variations of the local and average Nusselt numbers along with some transient and steady state velocity and temperature fields are demonstrated. The steady state results predict the existence of an optimum wall distance for the maximum average Nusselt number. The steady state and the transient Nusselt numbers are compared with the available experimental or theoretical results for a few cases. Their agreement is very good.
Histological findings in Morton's metatarsalgia
Authors: Meachim G. , Abberton M. J. 
Published: February 2006

AbstractMORTON'S metatarsalgia is a distinctive clinical condition characterised by paroxysmal, lancinating pain in the forefoot in the region of the metatarso‐phalangeal joints. The sensation is often described as that of (walking on a hot pebble). It is worse on walking, and typically eased by rest and by taking off the shoe. Manipulating the foot also sometimes eases the pain: it can cause sudden relief, the pain being replaced by a dull burning sensation.
Metastasising gliomas in young subjects
Authors: Eade O. E. , Urich H. 
Published: February 2006

AbstractALTHOUGH formation of metastases via the cerebrospinal fluid (CSF) is well recognised with medulloblastomas, this mode of spread is rare amongst other intracranial tumours. Metastasis outside the central nervous system was, for many years, thought never to occur (Bailey and Cushing, 1926). Several cases have now been described and were reviewed by Glasauer and Yuan (1963); we are presenting a further series of five gliomas spreading through the cerebrospinal fluid, with distant metastases in two instances, in an attempt to define their histological features and other circumstances that favour this mode of spread.
Aspergillus fumigatus endocarditis of an aortic homo‐graft with aneurysm of the ascending aorta
Authors: Doshi Rasikbala 
Published: February 2006

AbstractFungal endocarditis is an uncommon complication of cardiac surgery. Candida endocarditis following open heart surgery was first reported by Koelle and Pastor (1956) and since then 24 cases have been recorded. Nineteen cases were reviewed by McConnell and Roberts (1967) and three cases of their own were added. Two more cases have been reported since, one by Newsome, Lea and Russell Rees (1967) and the other by Kahn, Kane and Dean (1968). The fungi isolated from these 24 cases were Candida albicans in 14, other Candida species in seven, Aspergillus in two and Paecilomyces in one (Uys et al., 1963). The first case of Aspergillus endocarditis following open heart surgery was reported by Newman and Cordell (1964). This paper presents a case of Aspergillus fumigatus endocarditis on an aortic valve homograft.
Simulation‐based design of sheet molding compound (SMC) compression molding
Authors: Twu Jun‐Tien , James Lee L. , Chen Shia‐Chung 
Published: February 2006

AbstractThe design of moding tool and molding cycle for sheet molding compounds (SMC) is often expensive and time consuming. Computer simulation of the compression molding proces is a desirable approach to reduce experimental prototypes. The focus of this work is to develop an automatic optimization scheme utilizing an earlier developed SMC plrocess simulation program which is capable of simulating material flow, heat trensfer, and curing. The proposed scheme reduces computing time by using approximate responses, instead of actual simulated responses, to perform the optimization. The automated optimization package minimizes user intervention during optimal design by creating an automatic link between the optimization and simulation routines. A 2‐level factorial design combined with regression analysis is adopted to gather and analyze computed information, and to serve as the approximation formula. Two examples are presented to test the applicability of the optimization scheme.
Random glass mat reinforced thermoplastic composities. Part VII: A statistical approach to strength
Authors: Bushko Wit C. , Stokes Vijay K. 
Published: February 2006

AbstractLarge macroscopic‐scale variations in the tensile moduli and tensile strengths are charcteristic of random glass mat composites (GMT). The large‐scale, point‐to‐point variations in the local stiffness is characterized by a probability density function that can be used to predict the stiffness of parts only in a statistical sense. Weibull statistics widely used for modeling the scatter in the strength of brittle materials cannot be applied to the large variations in the strength of GMTs: The macroscopic stress field in brittle materials is assumed to be deterministic, while the stress field in GMTs varies randomly on a macroscopic scale. A statistical approach for characterizing the strength of GMTs is developed by combining an empirically established strength‐modulus correlation with the statistical characterization of the tensile modulus.
Carbon fiber modified composites of tetrafluoroethylene‐ethylene copolymers
Authors: Kostov G. K. , Nikolov A. T. 
Published: February 2006

AbstractComposites based on tetrafluoroethylene‐ethylene copolymers with graphitized polyacrylonitrile fibers were developed. The effect of the fiber length and concentration on the properties of the compositions was studied. Thermoactivation of the fibers was carried out and its influence on the properties of the tetrafluorethylene‐ethylene compositions was studied. Graphitized fibers possessing the higest content of oxygen‐containing functional groups thermoacttivated at 1073 K for 30 min exerted the highest reinforcing effec (∼40%). The relation between fibers finished with γ‐aminopropltriethoxysilance and theproperties of the compositions obtained was also studied. A synergetic effect on the compositions mechanical and thermal properties was observed for the modified carbon fibers, whereas the other properties remained almost the same. The additional reinforcement of the carbon compositions modified with fiber monocrystals ofalkali titanates in concentrattions from 0.5 to 5.0 Wt% strengthens the tetrafluoroethylene‐ethylene polymer matrix by increasing the dynamic modulus, hardness, and thermoresistance of the composities.
Polymerization of bisdithiafulvenes with conjugated spacers using oxidative dimerization
Authors: Naka Kensuke , Inagi Shinsuke , Murachi Yuki , Chujo Yoshiki 
Published: February 2006

AbstractNovel vinylogous tetrathiafulvalene (TTF) containing polymers (13 and 14) were prepared by the oxidative dimerization polymerization of bisdithiafulvenes. The obtained polymers were soluble in common organic solvents such as CHCl3. The structures of the polymers were confirmed by 1H NMR and cyclic voltammetry analysis. The number‐average molecular weights of 13 and 14 were estimated from gel permeation chromatography to be 3600 and 3800, respectively. Through the introduction of phenylene or phenylene–vinylene spacers, distortion between dialkoxybenzene and vinylogous TTF units was effectively prevented according to ultraviolet–visible analysis. The polymers exhibited a strong electron‐donating property investigated by cyclic voltammetry analysis. Chemical doping by CF3SO3H gave doped polymers having a cationic radical and a dication of a vinylogous TTF unit. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 2027–2033, 2006
Gas solubility of carbon dioxide in poly(lactic acid) at high pressures
Authors: Oliveira N. S. , Dorgan J. , Coutinho J. A. P. , Ferreira A. , Daridon J. L. , Marrucho I. M. 
Published: February 2006

AbstractThe sorption of carbon dioxide in poly(lactic acid) (PLA) was studied by quartz crystal microbalance at high pressures. To address the effect of the D isomer present in the polymer on the gas sorption, measurements were performed in PLA with two different L:D contents, 80:20 and 98:2. New data for the solubility of carbon dioxide in PLA 80:20 and PLA 98:2 over a temperature range from 303.2 to 323.2 K and up to 5 MPa are presented. The results obtained were correlated with the dual‐mode sorption model and the Flory‐Huggins equation. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 1010–1019, 2006
Prediction of solvent diffusion coefficient in amorphous polymers based on an equation‐of‐state
Authors: Lv Hong‐Ling , Wang Bao‐Guo 
Published: February 2006

AbstractThis study develops a modified free‐volume model to predict solvent diffusion coefficients in amorphous polymers by combining the Vrentas–Duda model with the Simha–Somcynsky (S‐S) equation‐of‐state (EOS), and all the original parameters can be used in the modified model. The free volume of the polymer is estimated from the S‐S EOS together with the Williams‐Landel‐Ferry fractional free volume, and the complex process of determining polymer free‐volume parameters in the Vrentas–Duda model and measuring polymer viscoelasticity can be avoided. Moreover, the modified model includes the influence of not only temperature but also pressure on solvent diffusivity. Three common polymers and four solvents are employed to demonstrate the predictions of the modified model. The calculation results are generally consistent with the experimental values. It is reasonable to expect that the modified free‐volume model will become a useful tool in polymer process development. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 1000–1009, 2006