bluuebunny/crossref_metadata_2025 huggingface dataset:
Testing the role of solvent surface tension in protein ionization by electrospray
Authors: Šamalikova Maria , Grandori Rita
Published: February 2005

This work was aimed at probing the influence of solvent surface tension on protein ionization by electrospray. In particular, we were interested in testing the previously suggested hypothesis that the charge‐state distributions (CSDs) of proteins in electrospray ionization mass spectrometry (ESI‐MS) are controlled by the surface tension of the least volatile solvent component. In the attempt to minimize uncontrolled conformational effects, we used acid‐sensitive proteins (cytochrome c and myoglobin) at low pH or highly stable proteins (ubiquitin and lysozyme) in the presence of low concentrations of organic solvents. A first set of experiments compared the effect of 1‐ and 2‐propanol. These two alcohols have similar chemico‐physical properties but values of vapor pressure below and above that of water, respectively. Both compounds have much lower surface tension than water. The solvents employed allowed testing of the influence of surface tension on protein spectra obtained from similarly denaturing solutions. The compared solvent conditions gave rise to very similar spectra for each tested protein. We then investigated the effect of the addition of dimethyl sulfoxide to acid‐unfolded proteins. We observed enhanced ionization in the presence of acetic or formic acid, consistent with the previously described supercharging effect, but almost no shift of the CSD in the presence of HCl. Finally, we analyzed thermally denatured cytochrome c, to obtain reference spectra of the unfolded protein in high‐surface‐tension solutions. Also in this case, the CSD of the unfolded protein was shifted towards lower m/z values relative to low‐surface‐tension systems. In contrast to the other results reported here, this effect is consistent with an influence of solvent surface tension on CSD. The magnitude of the effect, however, is much smaller than predicted by the Rayleigh equation. The results presented here are not easy to reconcile with the hypothesis that the maximum charge state exhibited by proteins in ESI‐MS reflects the Rayleigh‐limit charge of the precursor droplet. The data are discussed with reference to models for the mechanism of electrospray ionization. Copyright © 2005 John Wiley & Sons, Ltd.
Analysis of amphetamines and fentanyls by atmospheric pressure desorption/ionization on silicon mass spectrometry and matrix‐assisted laser desorption/ionization mass spectrometry and its application to forensic analysis of drug seizures
Authors: Pihlainen Katja , Grigoras Kestutis , Franssila Sami , Ketola Raimo , Kotiaho Tapio , Kostiainen Risto
Published: February 2005

The suitability of atmospheric pressure desorption/ionization on silicon mass spectrometry (AP‐DIOS‐MS) and matrix‐assisted laser desorption ionization mass spectrometry (AP‐MALDI‐MS) for the identification of amphetamines and fentanyls in forensic samples was studied. With both ionization techniques, the mass spectra recorded showed abundant protonated molecules, and the background did not disturb the analysis. The use of tandem mass spectrometry (MS/MS) allowed unambiguous identification of the amphetamines and fentanyls. AP‐DIOS‐MS/MS and AP‐MALDI‐MS/MS were also successfully applied to the identification of authentic compounds from drug seizures. Common diluents and tablet materials did not disturb the analysis and compounds were unequivocally identified. The limits of detection (LODs) for amphetamines and fentanyls with AP‐DIOS‐MS/MS were 1–3 pmol, indicating excellent sensitivity of the method. The LODs with AP‐MALDI‐MS/MS were about 5–10 times higher. Copyright © 2005 John Wiley & Sons, Ltd.
A novel rearrangement in electrospray ionization multistage tandem mass spectrometry of amino acid ester cyclohexyl phosphoramidates of AZT
Authors: Chen Yi , Yin Yingwu , Sun Xiaobin , Liu Xiaohong , Wang Haiyan , Zhao Yufen
Published: February 2005

Several amino acid ester cyclohexyl phosphoramidates of AZT as anti‐HIV prodrugs were synthesized and investigated by electrospray ionization tandem mass spectrometry (ESI‐MSn). A novel methoxy group migration from the carbonyl group to the phosphoryl group was observed in ESI‐MS2. This migration is believed to be a general pathway for ions with a methyl ester moiety at the γ‐position to a phosphoric acid moiety, which is assisted with metal ions such as Li+, Na+ and K+. Coordination between metal ions with both the carbonyl oxygen and phosphoryl oxygen might be a key factor responsible for this migration. Copyright © 2005 John Wiley & Sons, Ltd.
Wavenumber‐resolved interaction‐induced Raman scattering by a gaseous atomic mixture
Authors: Dixneuf S. , Chrysos M. , Rachet F.
Published: February 2005

A preliminary joint experimental and theoretical study of the depolarized, I||(ν), binary interaction‐induced Raman scattering profile by a gaseous atomic mixture is reported for the first time. An absolute‐unit calibration of the recorded scattering cross‐sections of the mixture permitted a straightforward comparison of the data with cross‐sections obtained with quantum mechanics. As a working system the Ne–Ar mixture was chosen, for which modern interatomic potential and incremental anistropy models are available for all the atomic pairs involved. Copyright © 2005 John Wiley & Sons, Ltd.
Theoretical introduction to nanoCARS: a local probing of nanocomposite materials with spectral profiles of coherent anti‐Stokes Raman scattering
Authors: Zheltikov A. M.
Published: February 2005

A theoretical introduction to coherent anti‐Stokes Raman scattering (CARS) as a local probe for nanocomposite materials is given. The interference nature of CARS spectra and the high spatial resolution make this non‐linear process an ideal local probe for the metrology of nanostructures and nanocomposites (nanoCARS). Local field enhancement of CARS in nanostructures allows the creation of efficient nanoCARS sensors. Copyright © 2005 John Wiley & Sons, Ltd.
Experimental demonstration of nanoCARS: coherent anti‐Stokes Raman scattering in mesoporous silica aerogels infiltrated with condensed‐ and gas‐phase Raman‐active materials
Authors: Konorov S. O. , Mitrokhin V. P. , Smirnova I. V. , Sidorov‐Biryukov D. A. , Fedotov A. B. , Zheltikov A. M.
Published: February 2005

Coherent anti‐Stokes Raman scattering (CARS) is shown to allow the reliable detection of Raman‐active modes of gas‐phase molecular nitrogen, and also toluene molecules in the condensed and gas phases infiltrated into mesoporous silica aerogels. We experimentally demonstrate a nanoscale extension of CARS methodology, referred to as nanoCARS, adapting CARS for local probing of nanostructures and nanocomposite materials, and also for the sensing of Raman‐active species in the liquid and gas phases in a nanocomposite host. Copyright © 2005 John Wiley & Sons, Ltd.
Collisional line broadening in the atmosphere of light particles: problems and solutions in the framework of semiclassical treatment
Authors: Buldyreva J. , Ivanov S. V. , Nguyen L.
Published: February 2005

For the case of perturbation by light particles, the computation of spectral line parameters by traditional semiclassical approaches reveals the problem of translational energy conservation. The rototranslational energy balance is, however, easily maintained within classical molecular dynamics. The line broadening of two ‘problematic’ systems, C2H2–He and CO2–He, is addressed from these two different points of view. In the framework of a traditional semiclassical approach, the non‐validity of the translational energy conservation hypothesis leads to a significant overestimation of the linebroadening for both systems. This overestimation is, however, substantially reduced for the ensemble of C2H2–He and CO2–He linewidths when a non‐perturbative completely classical method is employed. Used with caution, this latter approach therefore seems thus to be more appropriate for linewidth computations in the case of molecular systems of the type ‘heavy radiator + light perturber’. Copyright © 2005 John Wiley & Sons, Ltd.
Accurate pair‐anisotropy models out of a set of input experimental moments via a novel non‐linear inversion method
Authors: Chrysos M. , Dixneuf S.
Published: February 2005

We report a useful multiparameter Newton–Raphson method, yielding accurate pair‐anisotropy models from a set of low‐order experimental spectral moments. The method is applied to the depolarized binary collision‐induced scattering spectrum of argon. Its reliability is established through comparison between the (Ar)2 experimental spectrum, previously recorded by our group over a broad wavenumber domain, and quantum‐mechanical profiles whose inputs are various pair‐anisotropy models. Copyright © 2005 John Wiley & Sons, Ltd.
Four‐photon coherent spectroscopy of orientational motion of H2O molecules in liquid water
Authors: Bunkin A. F. , Nurmatov A. A. , Pershin S. M. , Vigasin A. A.
Published: February 2005

The unexpectedly narrow structure of Rayleigh wing spectra from 5 to 50 cm−1 was detected using four‐photon coherent laser spectroscopy. The observed features were compared with the IR water vapor absorption (from the HITRAN database) and with the spontaneous Raman spectrum in the vapor phase. The fairly good resemblance between our recorded four‐photon spectrum and the pure rotational spectra of H2O molecules in the gas phase allows the suggestion that a discernible proportion of water molecules may exhibit virtually free rotation in the liquid phase. Copyright © 2005 John Wiley & Sons, Ltd.
Characterization of nonlinear optical superlattices by means of ω‐k spectroscopy
Authors: Kitaeva G. Kh. , Tishkova V. V. , Penin A. N.
Published: February 2005

A method for measuring the spatial profiles of the second‐order non‐linear susceptibility χ(2)(z) in the bulk of periodically poled crystals and other structures was developed. The method is based on the general relation between the Fourier harmonics of χ(2)(z) and the parametric signal lineshape in the ω− k space which is governed by the dependence of the output signal intensity on the phase mismatch. The special cases of non‐linear interferometers, periodically poled crystals with stepwise or smoothed space χ(2)(z) profiles and Fibonacci‐type non‐linear superlattices were considered. Experimental schemes based on spontaneous parametric down‐conversion and the second harmonic generation were compared and discussed. Copyright © 2005 John Wiley & Sons, Ltd.
Single‐shot high‐resolution dual‐broadband CARS interferometric lineshape spectroscopy
Authors: Vereschagin K. A. , Smirnov V. V. , Stel'makh O. M. , Fabelinsky V. I. , Clauss W. , Klimenko D. N. , Oschwald M. , Vereschagin A. K.
Published: February 2005

A high‐resolution spectroscopic method that allows single‐shot spectra of Raman‐active molecular transitions in non‐stationary media to be obtained with a resolution of ∼0.1 cm−1 was developed. The method is based on application of a Fabry–Pérot interferometer to spectral analysis of the CARS signal from Raman transitions with further detection of an interference pattern by a two‐dimensional photo‐matrix. The implementation of a dual‐broadband (DBB) CARS configuration for effective spectral averaging over pump and Stokes laser spectra together with angular averaging of CARS intensities along the complete circumference of Fabry–Pérot interference patterns leads to a significant improvement of interferogram quality, so that nearly all of the single‐shot interference patterns obtained for Q‐branch lines of the hydrogen molecule in a gas probe volume became suitable for linewidth measurements. Copyright © 2005 John Wiley & Sons, Ltd.
Improved species concentration measurements using a species‐specific weighting procedure on rotational CARS spectra
Authors: Vestin Fredrik , Afzelius Mikael , Bengtsson Per‐Erik
Published: February 2005

Rotational coherent anti‐Stokes Raman spectroscopy (CARS) is used for measurements of temperatures and relative species concentrations. The evaluation of a rotational CARS spectrum is normally performed using a least‐squares fitting algorithm to find the best‐fit theoretical spectrum in a library of spectra calculated at different temperatures and relative concentrations. A general problem is that species with weak spectral features have a minor influence on the results in the standard evaluation procedure. A species‐specific weighting (SSW) procedure enhancing the influence of weak spectral features in the spectral fitting algorithm has therefore been developed. The SSW procedure was tested on the evaluation of low concentrations of O2 in mixtures with N2, and it is shown that both the accuracy and precision of single‐shot spectra concentration measurements are improved by use of the SSW evaluation procedure. Also, a comparison with previously used weighting procedures shows that this approach is superior. The application of the technique to oxygen concentration measurements in the product gas of a fuel‐lean flame is demonstrated. In addition, a test was made using the developed weighting procedure for thermometry, by applying spectral weighting to the rotational spectrum originating from the first thermally excited vibrational state. The precision of the temperature measurements was then slightly improved. Copyright © 2005 John Wiley & Sons, Ltd.
Phase‐matched coherent anti‐Stokes Raman scattering in isolated air‐guided modes of hollow photonic‐crystal fibers
Authors: Konorov S. O. , Fedotov A. B. , Serebryannikov E. E. , Mitrokhin V. P. , Sidorov‐Biryukov D. A. , Zheltikov A. M.
Published: February 2005

Hollow‐core photonic‐crystal fibers with a specially designed dispersion profile offer unique phase‐matching solutions for gas‐phase coherent anti‐Stokes Raman scattering (CARS) in isolated guided modes with a transverse radius of only a few micrometers. Efficient single‐mode CARS tuned to a Raman resonance with 2331 cm−1 Q‐branch vibrations of molecular nitrogen filling the hollow core of the photonic crystal fiber is demonstrated using the second‐harmonic output of a Q‐switched Nd:YAG laser and wavelength‐tunable dye‐laser radiation as pump fields. Copyright © 2005 John Wiley & Sons, Ltd.
Non‐linear Raman spectroscopy 75 years after the Nobel Prize for the discovery of Raman scattering and 40 years after the first CARS experiments
Authors: Zheltikov A. M. , Radi P.
Published: February 2005

We give a brief overview of the Proceedings of the European Conference on Non‐linear Optical Spectroscopy (ECONOS2004), held at the University of Erlangen, Germany, 4–6 April 2004. Conceptual and technical advances in non‐linear Raman techniques and interesting research results and engineering applications reported in this issue are in many ways representative of the state of the art in the field of non‐linear Raman spectroscopy 75 years after the Nobel Prize for the discovery of Raman scattering and 40 years after the first experiments on coherent anti‐Stokes Raman scattering (CARS), providing, at the same time, new and interesting perspectives on recent trends in this field. Copyright © 2005 John Wiley & Sons, Ltd.
Pathophysiology of spastic paresis. I: Paresis and soft tissue changes
Authors: Gracies Jean‐Michel
Published: February 2005

Spastic paresis follows chronic disruption of the central execution of volitional command. Motor function in patients with spastic paresis is subjected over time to three fundamental insults, of which the last two are avoidable: (1) the neural insult itself, which causes paresis, i.e., reduced voluntary motor unit recruitment; (2) the relative immobilization of the paretic body part, commonly imposed by the current care environment, which causes adaptive shortening of the muscles left in a shortened position and joint contracture; and (3) the chronic disuse of the paretic body part, which is typically self‐imposed in most patients. Chronic disuse causes plastic rearrangements in the higher centers that further reduce the ability to voluntarily recruit motor units, i.e., that aggravate baseline paresis. Part I of this review focuses on the pathophysiology of the first two factors causing motor impairment in spastic paresis: the vicious cycle of paresis–disuse–paresis and the contracture in soft tissues. Muscle Nerve, 2005
Pathophysiology of spastic paresis. II: Emergence of muscle overactivity
Authors: Gracies Jean‐Michel
Published: February 2005

In the subacute and chronic stages of spastic paresis, stretch‐sensitive (spastic) muscle overactivity emerges as a third fundamental mechanism of motor impairment, along with paresis and soft tissue contracture. Part II of this review primarily addresses the pathophysiology of the various forms of spastic overactivity. It is argued that muscle contracture is one of the factors that cause excessive responsiveness to stretch, which in turn aggravates contracture. Excessive responsiveness to stretch also impedes voluntary motor neuron recruitment, a concept termed stretch‐sensitive paresis. None of the three mechanisms of impairment (paresis, contracture, and spastic overactivity) is symmetrically distributed between agonists and antagonists, which generates torque imbalance around joints and limb deformities. Thus, each may be best treated focally on an individual muscle‐by‐muscle basis. Intensive motor training of the less overactive muscles should disrupt the cycle of paresis–disuse–paresis, and concomitant use of aggressive stretch and focal weakening agents in their more overactive and shortened antagonists should break the cycle of overactivity–contracture–overactivity. Muscle Nerve, 2005
Insight into the flow‐condition‐based interpolation finite element approach: solution of steady‐state advection–diffusion problems
Authors: Kohno Haruhiko , Bathe Klaus Jürgen
Published: February 2005

The flow‐condition‐based interpolation (FCBI) finite element approach is studied in the solution of advection–diffusion problems. Two FCBI procedures are developed and tested with the original FCBI method: in the first scheme, a general solution of the advection–diffusion equation is embedded into the interpolation, and in the second scheme, the link‐cutting bubbles approach is used in the interpolation. In both procedures, as in the original FCBI method, no artificial parameters are included to reach stability for high Péclet number flows. The procedures have been implemented for two‐dimensional analysis and the results of some test problems are presented. These results indicate good stability and accuracy characteristics and the potential of the FCBI solution approach. Copyright © 2005 John Wiley & Sons, Ltd.
Identifikation von Materialparametern für ein elasto‐plastisches Materialmodell für Fichtenholz
Authors: Fleischmann Martin , Eberhardsteiner Josef , Mang Herbert A.
Published: February 2005

Auf der Basis von biaxialen Experimenten behandelt dieser Beitrag die Identifikation von ausgewählten makroskopischen Materialparametern für ein orthotropes Einflächen‐Plastizitätsmodells für Fichtenholz. Das Hauptaugenmerk liegt in der Bestimmung der initialen Fließfläche sowie der Erfassung des Einflusses wesentlicher Holzmerkmale auf die Festigkeitseigenschaften. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Macromechanical characteristics deduced from tests on glass/epoxy composites with optical methods
Authors: Haasemann Georg , Thielsch Karin , Ulbricht Volker
Published: February 2005

Experimental results are required to verify the simulation results obtained by the homogenisation procedure of a biaxial weftknitted fabric reinforced composite with the Binary Model [1]. Tensile, bending and shear tests were performed to investigate and validate the elastic macro‐mechanical behaviour of the composite material. Beside other methods an optical whole‐field measuring system was used to estimate the deformation in all tests. Additionally, natural frequencies and the appropriate mode shapes of plates were used to get the elements of the compliance matrix. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Identification of Microstructural Components of Bitumen by Means of Atomic Force Microscopy (AFM)
Authors: Jäger Andreas , Lackner Roman , Eisenmenger‐Sittner Christoph , Blab Ronald
Published: February 2005

Accounting for the large variation of asphalt mixes, resulting from variations of constituents and composition, and from the allowance of additives, a multiscale model for asphalt is currently developed at the Christian Doppler Laboratory for “Performance‐based optimization of flexible road pavements”. The multiscale concept allows to relate macroscopic material properties of asphalt to phenomena and material properties of finer scales of observation. Starting with the characterization of the finest scale, i.e., the bitumen‐scale, Atomic Force Microscopy (AFM) is employed. Depending on the mode of measurement (tapping versus pulsed‐force mode), the AFM provides insight into the surface topography or stiffness and adhesion properties of bitumen. The obtained results will serve as input for upscaling in the context of the multiscale model in order to obtain the homogenized material behavior of bitumen at the next‐higher scale, i.e., the mastic‐scale. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Experimental Investigations on Polymeric Foams
Authors: Klar Oliver , Ehlers Wolfgang
Published: February 2005

The knowledge of the material behaviour of polymeric foams and their experimental investigation is the starting point for the structure of the chosen constitutive equations and for the following identification of the material constants therein. Especially for the parameter identification, it is necessary to make an adequate set of experimental data available.

In this regard, it is important that the experiments make the different kinds of material behaviour visible like elastic, plastic or viscous material properties. For this reason, the foam is observed under uniaxial tension and compression and under simple shear tests combined with different deformation states in axial direction. Unfortunately, due to different reasons, e.g., the foam must be sticked on the fastener to realize the tests mentioned above, it is very difficult to initialize a homogenous deformation state in the specimen. Therefore, the experiments are recorded with a standard digital camcorder to get local information of the deformation state by tracking single points with algorithms of the digital image processing. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Wavelet transformation in damage identification by dynamic tests
Authors: Knitter‐Piatkowska Anna , Garstecki Andrzej
Published: February 2005

The paper presents the problem of damage detection basing on the phenomenon of reflection and diffraction of waves at damage boundaries. Elastic waves in plate structures are considered. Damage is modeled as stiffness reduction at a small domain. One‐dimensional discrete signals, representing the velocity or acceleration measured at specified time and plate sections are analyzed using wavelet transform. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
An experimental validation of the Stochastic Subspace Identification
Authors: Kompalka A. S. , Reese S.
Published: February 2005

In this contribution we derive and experimentally validate the Stochastic Subspace Identification. Additionally we compare the results with an updated finite element model. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Extreme roll motions of ships
Authors: Kreuzer Edwin , Mestrom Rob , Pick Marc‐Andre
Published: February 2005

The ship capsizing problem is one of the major challenges in naval architecture. The criterion of the International Maritime Organization (IMO) regarding capsize stability is still not including dynamic loads. Existing mathematical models of ships taking into account all degrees of freedom as well as fluid–structure–interaction can hardly be used for stability analysis with common methods from nonlinear dynamics theory due to their complexity. For the development of new better suited models a test environment has been created. A first prototype for an experimental capsize analysis is presented in this paper. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Damage identification by wavelet transformation of data measured in thermal processes
Authors: Pozorski Zbigniew , Ziopaja Krzysztof
Published: February 2005

Damage detection by the analysis of steady‐state or transient thermal response of a structure is studied. 2D‐wavelet transform is employed. Measurement noise in temperature field is accounted for. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Parameter–identification of macroscopic material models based on virtual testing of given material mesostructures
Authors: Rieger Andreas , Miehe Christian
Published: February 2005

For many heterogeneous materials such as composites and polycrystals, the material modeling for the constituents on a representative mesoscale can be considered as known, including concrete values of their inherent material parameters. Typical examples are isotropic elastic–plastic models for the constituents of composites or anisotropic crystal–plasticity models for the grains of polycrystals. This knowledge can be exploited with regard to the modeling of the homogenized macroscopic response. In particular, parameters in macroscopic models may be identified by virtual experiments provided by a computational deformation–driving of representative mesostructures. This paper outlines the general concept for the parameter–identification of macroscopic materialmodels based on the virtual testing of given material mesostructures. The virtual test data are obtained in the form of multi–dimensional stress–strain paths by applying different deformation gradients to a given mesostructure. After specifying a corresponding macroscopic material model covering the observed effects on the macroscale, the material parameters are identified by a least–square–type optimization procedure that optimizes the macroscopic material parameters. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Three‐dimensional boundary layer on wind turbine blades
Authors: Dumitrescu Horia , Cardos Vladimir
Published: February 2005

This paper describes a three‐dimensional analysis of the laminar boundary layer that develops on the blades of an horizontalaxis wind turbine. The main aim was to investigate a fundamental phenomenon: the effect of rotation on the blade boundary layer of a wind turbine in conjunction with the widely observed phenomenon of stall‐delay. The separation position in retarded flows with pressure gradients is calculated and compared for the rotation and non‐rotation cases. It is concluded that the stall is linearly postponed due to the Coriolis force and the separation point is delayed as a result of increasing rotation speed or decreasing blade spanwise position. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Initial Opening of a Compressor Valve
Authors: Flade Georg , Will Gotthard , Steinrück Herbert
Published: February 2005

The initial opening of a compressor valve is investigated. The motion of the valve plate is essentially determined by the pressure distribution in the valve gap. Since the initial gap is extremly narrow a conventional CFD solution fails. Therefore the initial stages of the opening process are modelled by using an asymptotic expansion with respect to a small asepct ratio of the valve gap. The purpose of the analysis is to provide an initial condition for a CFD simulation of the valve dynamics. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Capillary driven Oscillations of a Free Liquid Interface under Non‐Isothermal Conditions
Authors: Gerstmann Jens , Michaelis Mark , Dreyer Michael
Published: February 2005

In this study the reorientation behavior of a free liquid interface in a partly filled right circular cylinder upon a step reduction in gravity is investigated experimentally. The experiments focus on the investigation of non‐isothermal boundary conditions on the liquid reorientation. The situation is similar to a spacecraft which enters a ballistic flight after the end of thrust. Heat flux between the liquid propellant and the tank wall occurs and influences the behavior of the liquid reorientation. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Some methods of the control of the separation region behind a backward facing step
Authors: Jaňour Z. , Jonáš P.
Published: February 2005

Preliminary experimental study was made on the prospects to affect the separation behind a backward facing step by means of suction or blowing through a gap at the foot of the step on one wall of the straight channel with rectangular cross section. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
First Order LSFEM for Fluid‐Structure Problems
Authors: Kayser‐Herold Oliver , Matthies Hermann G.
Published: February 2005

The Least‐Squares Finite Element Method (LSFEM) is an interesting alternative to the standard variational principles, which are used to solve partial differential equations. Advantages of the LSFEM are its robustness and the resulting symmetric positive definite matrices, which allow the use of robust iterative solvers like the CG method. In this paper we consider the application of the LSFEM for Fluid‐Structure Interaction (FSI) problems. Our model uses the LSFEM for the discretisation of the instationary incompressible Navier‐Stokes equations, which is coupled with a standard Galerkin FEM model for a linear elastic structure. The results for a simple model problem agree well with results obtained by other authors with different numerical schemes. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
On Transonic Marginal Separation
Authors: Kluwick Alfred , Streibl Bernhard
Published: February 2005

Laminar boundary‐layer separation near the leading edge of a thin airfoil is one of the principal factors that limits the lift force acting on the airfoil. Marginal separation, in particular, denotes the onset of separation which is accompanied by the formation of a short separation bubble. Using asymptotic analysis this effect is studied in the limit of high Reynolds number and for transonic external flow conditions. It is assumed that the fluid under consideration is a perfect gas and the airfoil surface is taken to be thermally insulated. Results to be presented include the analytical investigation of the emerging three layer structure, the associated transonic far field and the calculation of representative wall shear stress distributions. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Shock boundary layer interactions in dense gases
Authors: Kluwick Alfred , Wrabel Marcus
Published: February 2005

The concept of triple deck theory is applied to study laminar interacting boundary layers of dense gases in external purely supersonic flow. An impinging shock is generated at distances which are large compared to the upper deck thickness. As predicted by weakly nonlinear theory such a discontinuity may disintegrate into a sonic shock and an associated wave fan depending on its amplitude and the magnitude of the so called fundamental derivative. Incoming and outgoing waves are computed analytically by means of the method of multiple scales taking into account that mutual interaction effects between them are restricted to the linear upper deck region. The lower deck problem is solved numerically. The results show that it is possible to reduce the size of the separation bubble or even to avoid the occurrence of flow separation by choosing an optimal thermodynamic state. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Simulation of granular flow in silos
Authors: Leppert Caroline , Dinkler Dieter
Published: February 2005

A numerical model for granular flow is introduced in the light of the discharging of silos. To represent the dynamic and partly structure‐damaging processes during emptying, the granular material is treated as a fluid. Therefore, the Navier‐Stokes equations can be used to describe the flow. A discretisation scheme with space‐time finite elements is applied to both structure and fluid to allow a monolithic coupling of both continua [3]. Therefore, an investigation into the interaction between granular material and walls is possible.

The main part of this paper is the presentation of a constitutive model for granular media, which combines the non‐Newtonian fluid properties with the solid behaviour at rest. Bagnold [1] formulates first experimentally based relations for granular flows. Besides a number of phenomenological models, constitutive relations exist, that are derived from kinetic theory [2]. The extension of these fluid properties to the constitutive models in soil mechanics allows the description of granular flows in transition. Selected results show the influence of compressibility and inner friction to discharging phenomena. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The Trailing Edge Problem For Mixed Convection Flow Past a Horizontal Plate
Authors: Savic Ljubomir , Steinrück Herbert
Published: February 2005

The influence of buoyancy onto the boundary‐layer flow past a horizontal plate aligned parallel to a uniform free stream is characterized by the buoyancy parameter K = Gr/Re5/2 where Gr and Re are the Grashof and Reynolds number, respectively. An asymptotiy analysis of the complete flow field including potential flow, boundary layer, wake and interaction region is given for small buoyancy parameters and large Reynolds numbers in the distinguished limit KRe1/4 = O(1). (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Shear stress analysis in axially symmetric flow using the Padé approximation technique
Authors: Spillane Sandra , Redmond Brendan
Published: February 2005

This paper evaluates the shear stress on the surface of a circular cylinder in axially symmetric flow within the boundary layer. An extended solution is obtained by established techniques, e.g. asymptotic series or Pohlhausen method. A Padé approximation technique is applied to the extended solution obtained. The region of validity of the solution is extended and the results are then compared and examined against known approximate Pohlhausen and series solutions. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Mathematical modelling of compressible viscous fluid flow in a male rotor‐housing gap of screw machines
Authors: Vimmr Jan
Published: February 2005

This contribution is devoted to the mathematical modelling of a compressible viscous fluid flow through a 2‐D model of the male rotor‐housing gap in screw machines. Numerical solution of the nonlinear conservative system of the compressible Navier‐Stokes equations is obtained by means of the cell‐centred finite volume formulation of the explicit two‐step TVD MacCormack scheme proposed by Causon on a structured quadrilateral grid using the own developed numerical code. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Instationäre Strömung in einer Halbkugel
Authors: Wünsch Olaf
Published: February 2005

Es geht um die Strömung in einer mit Flüssigkeit gefüllten Halbkugel, die um eine Achse Drehschwingungen ausführt. Im Fall eines newtonschen Fluids werden interessante Strömungsformen in der Meridianebene beobachtet, die sich mit klassischen Theorien nicht erklären lassen. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Effects of the compatibilizer PE‐g‐GMA on the mechanical, thermal and morphological properties of virgin and reprocessed LDPE/corn starch blends
Authors: Pedroso A. G. , Rosa D. S.
Published: February 2005

The effects of the compatibilizer polyethylene grafted with glycidyl methacrylate (PE‐g‐GMA) on the properties of low‐density polyethylene (LDPE) (virgin and reprocessed)/corn starch blends were studied. LDPE (virgin and reprocessed)/corn starch blends containing 30, 40 and 50 wt% starch, with or without compatibilizer, were prepared by extrusion and characterized by the melt flow index (MFI), tensile test, dynamic mechanical analysis (DMTA) and light microscopy. The addition of starch to LDPE reduced the MFI values, the tensile strength and the elongation at break, whereas the modulus increased. The decreases in the MFI and tensile properties were most evident when 40 and 50 wt% starch were added. Blends containing 3 wt% PE‐g‐GMA had higher tensile strength values and lower MFI values than blends without compatibilizer. Light microscopy showed that increasing the starch content resulted in a continuous phase of starch. Copyright © 2005 John Wiley & Sons, Ltd.
Comparative study on the enzymatic polymerization of N‐substituted aniline derivatives
Authors: Nabid Mohammad Reza , Entezami Ali Akbar
Published: February 2005

A series of water‐soluble N‐substituted poly(alkylanilines) (PNAAs) have been enzymatically synthesized with a variety of groups, from methyl to n‐butyl, such as poly(N‐methylaniline), poly(N‐ethylaniline), poly(N‐butylaniline) and poly(N‐phenylethanolamine). The syntheses were made in the presence of poly(4‐sodium styrene sulfonate) (SPS) as a template and horseradish peroxidase (HRP) as a catalyst. The size and type of the groups have a great effect on the properties of the final polymers. UV‐vis spectroscopy and cyclic voltammetry measurements confirmed that for enzymatically synthesized PNAAs/SPS complexes, the electroactivity increased with the bulkiness of the substituents. These polymers have been studied in the doped and undoped states by FT‐IR and UV‐vis spectroscopy. Also these polymers show multiple and reversible optical transitions that can be ascribed to the formation of polaron and bipolaron states. Copyright © 2005 John Wiley & Sons, Ltd.
Diffusion and permeability of aldehydes into blends of natural rubber and chemically modified low molecular weight natural rubber
Authors: Akinlabi A. K. , Okieimen F. E. , Aigbodion A. I.
Published: February 2005

Low molecular weight natural rubber (LMWNR) obtained from natural rubber (NR) by depolymerization of natural rubber latex (NRL) was modified by epoxidation to 35% epoxide level to yield epoxidized low molecular weight natural rubber (ELMWNR). The ELMWNR was in turn modified in a solution of thioglycollic acid (TGA) (0.5 mol phr) to yield a product of 20% conversion of its initial LMWNR epoxide. Blends of NR with LMWNR, ELMWNR and epoxidized low molecular weight natural rubber thioglycollic acid (ELWMNR‐TGA) adduct were made. The mixes were vulcanized at 150°C for 20 min before determining the system parameters (n and k), the sorption (S), diffusion (D) and permeability (P) of the vulcanizates in acetaldehyde and formaldehyde solutions at three different temperatures (25, 40 and 60°C) for a period of 90 days. The sorption, diffusion and permeability of the vulcanizates were found to be temperature dependent. The vulcanizates containing ELMWNR were found not to be easily penetrated by both acetaldehyde and formaldehyde when compared with base mix A that is vulcanizates with only NR. The reaction system was found not to be spontaneous but dependent on the activation energies. Copyright © 2005 John Wiley & Sons, Ltd.
Frontal polymerization of acrylic monomers for the consolidation of stone
Authors: Vicini Silvia , Mariani Alberto , Princi Elisabetta , Bidali Simone , Pincin Silvia , Fiori Stefano , Pedemonte Enrico , Brunetti Antonio
Published: February 2005

Polymeric products are largely used for consolidation of stone in the field of cultural heritage. Nevertheless, the main problem of polymeric compounds is related to their macromolecular nature, it being difficult for a polymer to penetrate inside the pores which may have a very small diameter. These considerations are the starting points for in situ polymerization. According to this technique, not the pre‐formed polymer, but the monomer is introduced into the stone and it is polymerized in situ in a subsequent step.

Frontal polymerization (FP) is a particular technique in which the heat released by the exothermal reaction of monomer to polymer conversion is exploited to promote the formation of a hot traveling front able to propagate and self‐sustain the reaction.

In the present work, FP is performed inside the pores of the stone and the results lead to the conclusion that the hot front is still active in the presence of an inorganic material which dissipates partially the heat released during the polymerization. In addition some recent applications of FP are discussed in comparison with the traditional polymerization for the in situ consolidation and protection of stones. Copyright © 2005 John Wiley & Sons, Ltd.
Characterization of dendritic cells in differentiated thyroid cancer
Authors: Tsuge Kaori , Takeda Hiroaki , Kawada Sumio , Maeda Kunihiko , Yamakawa Mitsunori
Published: February 2005

In this study, the types and localization pattern of dendritic cells (DCs), the expression of chemokines on carcinoma cells and of the relevant receptors on DCs, and the adhesion molecules expressed on vascular endothelial cells and DCs were examined in thyroid carcinomas. Papillary carcinoma had a higher frequency of CD1a+ immature DCs than other thyroid tumours. Macrophage inflammatory protein (MIP)‐3α was expressed strongly on the majority of papillary carcinoma cells and weakly on a minority of follicular carcinoma cells. DCs positive for chemokine receptor‐6 (CCR‐6) were densely accumulated in papillary carcinoma. DC‐SIGN+ DCs were accumulated in papillary carcinoma but rarely in follicular carcinoma. A binding assay for DC‐SIGN‐mediated adhesion of isolated DCs revealed significant inhibition of DC adhesion to papillary carcinoma tissues by neutralizing antibodies against intercellular adhesion molecule‐2 or DC‐SIGN. These results clearly indicated marked differences between papillary carcinoma and follicular carcinoma in the accumulation of immature DCs, in MIP‐3α expression on carcinoma cells, and in the frequency of CCR‐6+ DCs and DC‐SIGN+ DCs. Copyright © 2005 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Elevated nuclear maspin expression is associated with microsatellite instability and high tumour grade in colorectal cancer
Authors: Bettstetter Marcus , Woenckhaus Matthias , Wild Peter J , Rümmele Petra , Blaszyk Hagen , Hartmann Arndt , Hofstädter Ferdinand , Dietmaier Wolfgang
Published: February 2005

Maspin, a member of the serpin family, has been reported to suppress metastasis and angiogenesis in breast and prostate cancers. Overexpression of maspin was associated with adverse prognostic features in several other tumours. In this study, expression of maspin was analysed in 41 colorectal carcinomas with high‐frequency microsatellite instability (MSI‐H) and 159 microsatellite stable colorectal cancers (MSS/MSI‐L) by immunohistochemistry (IHC) and partly by relative quantitative real‐time RT‐PCR and western blot analyses. Significant upregulation of maspin expression was found in MSI‐H tumours compared to both MSS/MSI‐L tumours and matched benign colonic mucosa. Increased maspin expression was also found in three MSI‐H colon cancer cell lines, but not in three MSS colon cancer cell lines by RT‐PCR and western blot analyses. Regulation of maspin expression depended on promoter methylation as tissue specimens and cell lines expressing maspin showed unmethylated maspin promoters, whereas promoter hypermethylation was found in specimens with loss of maspin expression. Intense nuclear maspin immunostaining was seen specifically in MSI‐H tumours (p = 0.013), de‐differentiated tumours (p = 0.006), and at the invasion front. These findings provide new insights into the role of maspin in colorectal cancer progression and may be useful for diagnosis and treatment strategies. Copyright © 2005 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Frequency of BRAF T1796A mutation in papillary thyroid carcinoma relates to age of patient at diagnosis and not to radiation exposure
Authors: Powell Ned , Jeremiah Steve , Morishita Mariko , Dudley Ed , Bethel Jackie , Bogdanova Tetyana , Tronko Mykola , Thomas Gerry
Published: February 2005

In this study, the frequency of BRAF mutation was investigated in a series of 67 cases of papillary thyroid cancer (PTC) in patients from Ukraine. Thirty‐two patients were aged 30 years or older at the time of diagnosis and 35 were under 16. Tumour was microdissected from paraffin wax‐embedded sections, DNA extracted, and the presence of the BRAF T1796A mutation demonstrated by two different methods: PCR followed by restriction enzyme digestion or primer extension assay and detection using MALDI‐TOF mass spectrometry. Eighteen (58%) of the adult cases, but only one of the 35 cases aged less than 16 harboured a BRAF T1796A mutation. There was complete agreement between the two methods used, suggesting that the MALDI‐TOF assay is a robust alternative to conventional mutation analysis. RET rearrangement was also examined in the young cohort. The overall frequency of RET rearrangement was 45.7%. Eight of the younger group of patients were born after 1 December 1986 and were therefore not exposed to radioiodine in fallout from Chernobyl. None of the PTCs from these eight patients were positive for BRAF mutation. The frequency of RET rearrangement was 44% in the 27 cases exposed to radiation and 50% in the eight not exposed. These results suggest that the different molecular biological profiles observed are associated with the age of the patient at diagnosis with PTC, rather than being associated with radiation exposure. Copyright © 2005 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Morphology profiles obtained by reaction‐induced phase separation in epoxy/polysulfone/poly(ether imide) systems
Authors: Giannotti MI , Mondragon I , Galante MJ , Oyanguren PA
Published: February 2005

The reaction‐induced phase separation in epoxy/aromatic diamine formulations simultaneously modified with two immiscible thermoplastics (TPs), poly(ether imide) (PEI) and polysulfone (PSF), has been studied. The epoxy monomer was based on the diglycidyl ether of bisphenol A (DGEBA) and the aromatic diamine was 4,4′‐methylenebis(3‐chloro 2,6‐diethylaniline) (MCDEA). Phase‐separation conversions are reported for various PSF/PEI proportions for blends containing 10 wt% total TP. On the basis of phase‐separation results, a conversion–composition phase diagram at 200 °C was compiled. This diagram was used to design particular cure cycles in order to generate different morphologies during the phase‐separation process. It was found that, depending on the PSF/PEI ratio employed, a particulate or a morphology characterized by a distribution of irregular PEI‐rich domains dispersed in an epoxy‐rich phase was obtained for initially miscible blends. Scanning electron microscopy (SEM) characterization revealed that the PEI‐rich phase exhibits a phase‐inverted structure and the epoxy‐rich matrix presents a bimodal size distribution of TP‐rich particles. For PSF/PEI ratios near the miscibility limit, slight temperature change result in morphology profiles. Copyright © 2005 Society of Chemical Industry
Investigation on the effect of the presence of hyperbranched polymers on thermal and mechanical properties of an epoxy UV‐cured system
Authors: Sangermano Marco , Malucelli Giulio , Bongiovanni Roberta , Priola Aldo , Harden Adrian
Published: February 2005

The use of hydroxyl‐functionalized hyperbranched polymers (HBPs) (Boltorn® H20, H30 and H40) was investigated with respect to a UV‐cured epoxy system. Their presence induced an increase of the final epoxy conversion, which was interpreted on the basis of a chain‐transfer reaction. A decrease of the Tg values in the photocured films was observed when the amount of HBP additive in the photocurable formulation was increased. When the amount of HBP in the photocurable resin was increased, the density of photocured films increased, indicating a decrease on the free volume. Moreover, a clear increase in toughness was observed and attributed to the plasticization effect induced by the presence of HBP. This effect is particularly interesting for epoxy thermosets, which are characterized by good mechanical properties, although they are brittle and fragile. By increasing the toughness properties of these photocured resins it may be possible to broad their applications. Copyright © 2005 Society of Chemical Industry