bluuebunny/crossref_metadata_2025 huggingface dataset:
Computation of accurate nodal derivatives of finite element solutions: the finite node displacement method
Authors: Ilinca F. , Pelletier D.
Published: January 2007

This paper presents a new method for extracting high‐accuracy nodal derivatives from finite element solutions. The approach involves imposing a finite displacement to individual mesh nodes, and solving a very small problem on the patch of surrounding elements, whose only unknown is the value of the solution at the displaced node. A finite difference between the original and perturbed values provides the directional derivative. Verification is shown for a one‐dimensional diffusion problem with exact nodal solution and for two‐dimensional scalar advective–diffusive problems. For internal nodes the method yields accuracy slightly superior to that of the superconvergent patch recovery (SPR) technique of Zienkiewicz and Zhu (ZZ). We also present a variant of the method to treat boundary nodes. In this case, the local discretization is enriched by inserting an additional mesh point very close to the boundary node of interest. We show that the new method gives normal derivatives at boundary points that are consistent with the so‐called ‘auxiliary fluxes’. The resulting nodal derivatives are much more accurate than those obtained by the ZZ SPR technique. Copyright © 2007 Crown in the right of Canada. Published by John Wiley & Sons, Ltd.
British attitudes on nuclear weapons
Authors: Byrom Andy
Published: January 2007

In an increasingly unstable world post‐911, the political landscape seems to be continually shifting, with many of the old certainties around combatants and how to wage war being subject to revision—not least the role of nuclear weapons in a post‐Cold War age. But have our attitudes towards the development and use of nuclear weapons fundamentally changed over the past 50 years? Andy Byrom, Associate Director at Ipsos MORI, examines data from the previous half‐century which lead to some surprising conclusions.

Copyright © 2007 John Wiley & Sons, Ltd.
Transparency in government communication
Authors: Fairbanks Jenille , Plowman Kenneth D. , Rawlins Brad L.
Published: January 2007

Basic to a successful democracy is the existence of a public informed about government actions. This requires government information to be open and accessible to the public. This study sought to understand how communicators in government value and practice transparency. Constant comparative thematic analysis of 18 semi‐structured interviews of government communicators revealed a transparency model for government communication. This paper outlines that model and identifies practices and structures that promote transparent communication practices.

Copyright © 2007 John Wiley & Sons, Ltd.
Characterisation and Modelling of Piezoceramic Actuator Hystereses
Authors: Bossong Heiko , Lentzen Sven , Schmidt Rüdiger
Published: January 2007

Piezoelectric ceramics are often used as actuators in smart structures technology. In the vast majority of papers dealing with this topic only linear constitutive relations are used. However, the electric field‐strain relations of such actuators show hysteretic behaviour, which means that the piezoelectric coupling coefficient is not constant.

In this study the hysteresis of a mechanically unconstrained actuator is obtained using the Michelson interferometry. The hysteretic behaviour is modelled by a Preisach model. Using these experimental data, for the modelling of an active structure with embedded piezoelectric actuators the actual coupling coefficient can then be determined with the help of the Preisach model. With this procedure the actuation strain of an embedded actuator, including the physical nonlinearities, can be calculated using the material characteristics obtained for an unconstrained actuator.

For an experimental validation of the method outlined above, a Lead Zirconate Titanate (PZT) actuator is characterised experimentally and then glued to a cantilever beam. Then, the tip displacement of the actuated beam is determined experimentally and simulated numerically using the above method. The experimental and numerical results agree reasonably well if the shear lag due to the bonding layer between the actuator and the structure is taken into consideration. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
3D Simulation of Point Defect Migration in Ferroelectrics
Authors: Goy Oliver , Mueller Ralf , Gross Dietmar
Published: January 2007

Electric fatigue in functional materials involves a set of phenomena which lead to the degradation of materials with an increasing number of electrical cycles. Ionic and electronic charge carriers, later 0 as point defects, interact with each other and with microstructural elements in the bulk and with interfaces, which can lead to degradation, or finally to mechanical damage and dissociation reactions, see e.g. [1].

With this in mind, efforts are made to calculate the fields caused by point defects to simulate their interaction as well as to verify the used material parameters. Here, a material with linear electro mechanical coupling is used. The applied methods are integral transforms (Radon Transform) and a combination of Difference Methods and a Fast Fourier Transform to obtain solutions in an infinite domain and under periodic boundary conditions, respectively. The point defect interaction is studied within the framework of material or configurational forces. These forces are used in combination with reasonable kinetic laws to simulate defect migration, cf. [2]. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A hybrid element formulation for electromechanical problems
Authors: Kurzhöfer Ingo , Schröder Jörg
Published: January 2007

The difficulty in the modeling of ferroelectric materials is the coverage of the complicated interactions between electrical and mechanical quantities on the macroscale, which are caused by switching processes on the microscale. In the present work we present an electric hybrid element formulation where the stresses and the electric fields are derived by constitutive relations as presented in [1]. Therefore the displacements, the electric potential and the electric displacements are approximated by bilinear ansatz functions. Applying a static condensation procedure we obtain a modified finite element formulation governed by the degrees of freedoms associated to the displacements and the electric potential. The anisotropic material behavior is modeled within a coordinate‐invariant formulation [6] for an assumed transversely isotropic material [4]. In this context a general return algorithm is applied to compute the remanent quantities at the actual timestep. Resulting hysteresis loops for the ferroelectric ceramics are presented. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
On Variational Based Scale‐Bridging of Inelastic Composites
Authors: Birkle Manuel , Gürses Ercan , Miehe Christian
Published: January 2007

The paper discusses formulations for the theoretical and numerical analysis of inelastic composites with scale separation. The basic underlying structure is a canonical variational setting in the fully nonlinear range based on incremental energy minimization. We focus on formulations of strain–driven homogenization for representative composite aggregates with emphasis on the development of canonical families of algorithms based on Lagrange and penalty functionals to cover alternative boundary constraints of (i.) linear deformations, (ii.) periodic deformations and (iii.) uniform tractions. As a key result, we present a compact matrix formulation for homogenization covering introduced alternative boundary constraints. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
From microscopic to macroscopic modelling of cellular materials
Authors: Chatzouridou Anthippi , Ebinger Tobias , Diebels Stefan
Published: January 2007

In the present contribution the modelling of foam‐like materials is discussed on different scales. Such materials can be foams, sponges, granular media or even hard biological tissues, and their common characteristic is that their macroscopic response is strongly influenced by the iteraction with the cellular microstructure. The individual cells start playing a role when their size becomes on the order of the macroscopic dimensions of the test specimen, leading to size effects, e. g. [1]. To investigate size effects on the macroscale an extended continuum approach is required taking into consideration the microstructural mechanism. Alternatively one can obtain a macroscopic description which includes the microstructural information using a numerical homogenisation procedure. In this way a connection between the discrete quantities of the microscale (e. g. forces) to quantities of an equivalent continuum (e. g. stresses) can be established. The purpose of this study is to investigate the relation between the above mentioned modelling approaches in terms of the involved parameters using procedures of parameter identification. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Homogenisation of elasto‐plastic open‐celled foams
Authors: Demiray S. , Becker W. , Hohe J.
Published: January 2007

The effective yield behaviour of open‐celled metal foams is studied by a micro‐mechanical model. As a surrogate model for the sponge‐like microstructure the simplified Kelvin foam is used. The yield loci in strain space and stress space are constructed by conducting numerical experiments. For the determination of the effective stresses a strain‐energy based homogenisation procedure is adopted. The numerical examples show that the initial yield surface in the normal strain space is similar to a polyhedron with sharp corners. The further evolution of the yield surface is characterized by kinematic and isotropic hardening effects. In addition, the stress yield surface may rotate under certain loading conditions. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
On the simulation of textile reinforced composites and structures
Authors: Haasemann Georg , Ulbricht Volker
Published: January 2007

This paper presents experimental and numerical methods to perform simulations of the mechanical behavior of textile reinforced composites and structures. The first aspect considered refers to the meso‐to‐macro transition in the framework of the finite element (FE) method. Regarding an effective modelling strategy the Binary Model is used to represent the discretized complex architecture of the composite. To simulate the local response and to compute the macroscopic stress and stiffness undergoing small strain a user routine is developed. The results are transfered to the macroscopic model during the solution process.

The second aspect concerns the configuration of the fiber orientation and textile shear deformation in complex structural components. To take these deformations which affect the macroscopic material properties into account they are regarded in a macroscopic FE model. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Fourier Series for Continua with Microstructure
Authors: Kaßbohm S. , Müller W. H. , Silber G. , Feßler R.
Published: January 2007

Based on the idea of the Cosserats at the beginning of the 20th century, Mindlin, Tiersten, Toupin, Rivlin, Green, Trostel et al. developed theories for generalized continua in the 1960s. Currently, such theories for continua with microstructure are extended in micromechanics, fluid mechanics, etc. by various scientists. All such theories follow the same purpose of a more precise material description embedded in a continuum theory. In the following article the well‐known Cosseratcontinuum is used for the calulation of strains and stresses in Representative Volume Elements (RVEs) with arbitrary stiffness distribution and periodic boundary conditions. Restricting the problem to small displacements and linear elasticity results in linear equations of motion, that can be solved iteratively by means of Fourier series. It is pointed out that other types of generalized continua can be analyzed in the same manner. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Investigation, Modelling and Analysis of stiffened GFRP‐Samples
Authors: Kreikemeier Janko , Berger Harald , Gröbel Karl‐Heinz , Gabbert Ulrich
Published: January 2007

Glasfibre structures feature high potentials for optimization and substitution of conventional materials like steel and aluminum and their alloys. The paper deals with the insertion of glasfibre trusses into thin glasfibre structures to reinforce them. The effective material properties of the glasfibre structures were estimated by experiments and simulations. Furthermore the Young's modulus of the trusses was obtained by bending tests and tension tests. A comparison between bending experiments and bending simulations is given. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Transversal walls versus vortex walls in magnetic nanowires
Authors: Kühn Katharina
Published: January 2007

In numeric simulations of magnetic nanowires several groups have observed two different types of reversal modes. It is suggested that the reversal mode corresponds to an energetically optimal domain wall profile. We investigate the energy minimisation problem in different regimes of thickness. When the radius goes to zero, the energy minimisation problem Γ‐converges to a reduced local one dimensional problem. Thus for small radii, minimisers of the energy functional are almost constant on the cross section. This is not the case for big radii. For radius to infinity, a class of magnetisations with a vortex has the optimal energy scaling. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
On Micromechanical Damage Modelling Of Fibre Reinforced Composites
Authors: Matzenmiller A. , Koester B.
Published: January 2007

The numerical analysis of engineering structures is usually based upon the assumption of a homogeneous as well as a continuous medium. Macroscopic homogeneity is maintained also for heterogeneous, fibre reinforced composite structures by replacing the inhomogeneous medium through a model of a mathematically homogenized material. The constitutive behaviour is then described in terms of volume averaged quantities that smear the heterogeneities of the microscale. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
On a Sachs bound for stress‐induced phase transformations in polycrystalline shape memory alloys
Authors: Schlömerkemper Anja
Published: January 2007

In earlier work [3], a Sachs and a Taylor bound on the transformation yield stress in shape memory polycrystals were derived in the context of a variational model. The aim of this article is to compare the Sachs with the Taylor bound for cubic‐toorthorhombic phase transformations under biaxial loading, where the material parameters are chosen explicitly (CuAlNi). It turns out that the gap between the two bounds can be quite large depending on the underlying texture and the loading direction. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
From particle dynamics to micropolar media: a localization study
Authors: Scholz B. , Ehlers W.
Published: January 2007

Granular materials show a complex stress‐strain behavior depending on the stress state and the load history. In case of biaxial tests and compaction loading situations, one furthermore observes localization effects, e. g., by the formation of shear bands. For the simulation of such a material behavior two different methods can be applied. Firstly, the microscopic model which means the direct modeling of the single material grains on the basis of the Molecular Dynamic methods. The second one is a macroscopic approach, whereby, the fundamental effect on the microscale, the rotations of the single grains, are considered by use of the micropolar or Cosserat theory. The intend of this contribution is to demonstrate that the Cosserat theory is a physical correct way for the description of granular materials. Therefore, it will be shown that in both methods the occurrence of localization zones (shear bands) is connected with the appearance of curvatures in the material combined with couple stresses, which indicates a Cosserat material. The required curvature and couple stress tensors are obtained in the macroscopic theory as a direct result of the computation, whereas by use of the microscopic theory the translations and rotations as well as contact forces are obtained as the direct result. Thus, homogenization methods basing on an appropriate Representative Elementary Volume (REV) are required. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Homogenization for rate‐independent systems
Authors: Timofte Aida , Mielke Alexander
Published: January 2007

This paper is devoted to the homogenization for a class of rate‐independent systems described by the energetic formulation. The associated nonlinear partial differential system has periodically oscillating coefficients, but has the form of a standard evolutionary variational inequality. Thus, the model applies to standard linearized elastoplasticity with hardening. Using the recently developed methods of two‐scale convergence, periodic unfolding and the new introduced one, periodic folding, we show that the homogenized problem can be represented as a two‐scale limit which is again an energetic formulation, but now involving the macroscopic variable in the physical domain as well as the microscopic variable in the periodicity cell. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Particle‐Laden Flow Simulation in a Cyclone Separator
Authors: Shalaby Hemdan , Wozniak Klaus , Wozniak Günter
Published: January 2007

The particle‐laden flow of a cyclone separator for industrial applications at a Reynolds number of Re = 140, 000 has been studied numerically. Due to the nature of cyclone flows, which exhibit highly curved streamlines and anisotropic turbulence, we used the advanced turbulence model Large Eddy Simulation (LES). Our LES reveals qualitative agreement with experimental data, but requires higher computer capacity and longer running times compared to other turbulence models. The results of the continuous phase flow computations were generated first and served as a basis for modeling the behavior of solid particles in the separator. Modeling of the solid particle motion in the cyclone was performed applying a one‐way coupling between the gas flow field and the particles. The cyclone separation efficiency and particle trajectories have been studied in detail. Separation efficiency results show satisfying agreement between LES data and experimental results. It turned out that the particle cut‐off diameter for a particle material density of 2500 kg/m3 is approximately 1.3 μm. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A numerical methods for 2‐D flow of flapping airfoil
Authors: Dumitrache Alexandru
Published: January 2007

To study the physics of the flow of flapping flight, a numerical model for the two‐dimensional flow around an airfoil undergoing prescribed oscillatory motions in a viscous flow is described. The model is used to examine the flow characteristics and power coefficients of a symmetric airfoil heaving sinusoidally over a range of frequencies and amplitudes. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Influence of eddies on heat transfer in Couette flow
Authors: Scholle M. , Aksel N.
Published: January 2007

Under creeping flow conditions, we consider the steady Couette flow of a Newtonian fluid between two plates, one of them planar, the other one with a sinusoidal profile. Recent analytical studies on the velocity field revealed the formation of kinematically induced eddies in the valleys of the plate topography and the influence of these eddies on drag force and flow rate. The influence of these eddies on the convective heat transfer is the subject of our paper. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Über die exzentrische Zylinderspaltströmung bei engen Spaltweiten
Authors: Stücke Peter , Schwarz Mike , Scurtu Nicoleta , Egbers Christoph
Published: January 2007

Es werden die Strömungsverhältnisse im Ringspalt zweier koaxial angeordneter Zylinder mit den Mitteln der Strömungsvisualisierung untersucht. Dabei wird der Übergangsbereich von laminarer Couette‐Strömung zu Taylor‐Wirbel‐Strömung bei konzentrischer und exzentrischer Anordnung der Zylinder und relativen Spaltweiten von unter 0.1 untersucht. Bei konzentrischer Zylinderanordnung kann die Stabilitätsgrenze der laminaren Couette‐Strömung für Reynolds‐Zahlen von 150 bis 400 bestätigt werden. Bei exzentrischer Anordnung der Zylinder ändern sich die Strömungsverhältnisse grundlegend. Mit zunehmender Exzentrizität verschiebt sich die Stabilitätsgrenze zu höheren Reynolds‐Zahlen. In Abhängigkeit von der Reynolds‐Zahl bilden sich Taylor‐Wirbel bei bestimmten Exzentrizitäten nur im konvergenten Teil des Spaltes. Der Bereich um die engste Spaltweite ist dann frei von Taylor‐Wirbeln. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Modelling of Newtonian and Non‐Newtonian Incompressible Fluid Flow
Authors: Vimmr Jan
Published: January 2007

This paper deals with numerical simulation of steady laminar incompressible Newtonian and non‐Newtonian fluid flow. The viscosity of non‐Newtonian fluid is modelled using the fluid power law. The mathematical model is described by the non‐linear conservative system of the incompressible Navier‐Stokes equations that is solved using the explicit two‐step MacCormack scheme with artificial viscosity together with the pseudo‐compressibility method. The spatial discretization is performed by the cell‐centred finite volume method on a structured quadrilateral grid. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Perceived disability, fatigue, pain and measured isometric muscle strength in patients with post‐polio symptoms
Authors: Lygren Hildegunn , Jones Kari , Grenstad Torunn , Dreyer Vibeke , Farbu Elisabeth , Rekand Tiina
Published: January 2007

Background and Purpose. Several years after the acute polio illness, patients may develop new post‐polio symptoms. The purpose of the present study was to evaluate patients with post‐polio symptoms with regard to perceived fatigue, functional ability, muscle strength, pain and with regard to measured physical fitness and isometric muscle strength. In addition, the relationship between the results of these subjective and objective measurements was investigated. Method. This was a prospective cross‐sectional study in which 32 patients with post‐polio symptoms were included. Main outcome measures were the Fatigue Severity Scale (FSS), the Disability Rating Index (DRI), pain intensity, pain distribution, self‐reported and measured muscle strength and oxygen uptake. Results. A marked reduction in isometric muscle strength compared to normal data, high scores in fatigue, widespread pain, low oxygen uptake and difficulties in performing some daily activities were found. Self‐reported general muscle strength, pain intensity and pain distribution correlated significantly with patients' perceived fatigue and function at the activity level. There was no significant correlation between self‐reported and measured results except for that found between isometric muscle strength in the legs and patients' perceived general muscle strength and oxygen uptake. Conclusions. Evaluation of pain intensity, pain distribution, perceived muscle strength, fatigue and ability to perform daily tasks reveals important aspects of health status in patients with post‐polio symptoms. Reduction in isometric muscle strength was not reflected in those tests or in reported symptoms, and should be monitored independently using a sensitive assessment tool. Accurate screening of isometric muscle strength in isolated muscle groups contributes to therapeutic management in making a functional diagnosis at the level of body function and structure when designing specific training programmes and in motivating patients. An evaluation combining self‐reports with sensitive muscle strength measures provide supplementary information and is appropriate for evaluating these patients in physiotherapy practice. Copyright © 2007 John Wiley & Sons, Ltd.
Architecture of cylinders with implications for materials with negative Poisson ratio
Authors: Pikhitsa Peter V.
Published: January 2007

It is known that auxetic properties (for example, negative Poisson ratios, that is, when a solid experiences lateral expansion under stretching instead of lateral contraction) start showing themselves in materials where there is a certain kind of geometrical orientational correlations between “rigid” constituents. Properly arranged orientational degrees of freedom of building blocks govern the characteristic distances in auxetic materials and thus determine the way in which the materials contract or expand. Very often the building blocks are filamentous. We suggest a way to arrange filamentous objects into highly interwoven regular structures which may exhibit auxetic properties with negative Poisson ratio. Our purely geometrical consideration can be extended to an irregular positional arrangement. This implies that a solid of sufficiently dense “random” arrangements of filaments (for example, “wool” of nanowires or of carbon nanotubes) may become auxetic. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Poisson's ratio of simple planar ‘isotropic’ solids in two dimensions
Authors: Tretiakov Konstantin V. , Wojciechowski Krzysztof W.
Published: January 2007

The influence of molecular geometry on the Poisson's ratio has been investigated for a few two‐dimensional (2D) hard body systems (hard discs, hard dimers, hard cyclic trimers, and hard cyclic hexamers) forming elastically isotropic solid phases. The Poisson's ratio of the studied periodic and aperiodic solids was determined by Monte Carlo simulations using the analysis of the box fluctuations in the constant pressure ensemble (NpT) with variable box shape. The results obtained for all the studied systems showed that the Poisson's ratio grows when the density is decreased. It has been also found that the Poisson's ratio decreases with increasing number of discs in the molecule and its value for hard trimers is negative near close packing. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Is there a ‘matrix suppression effect’ under fast‐atom bombardment liquid secondary ion mass spectrometry of ionic surfactants in glycerol?
Authors: Kosevich Marina V. , Chagovets Vitalij V. , Shelkovsky Vadim S. , Boryak Oleg A. , Orlov Vadim V. , Gomory Agnes , Vegh Peter
Published: January 2007

Some features of a ‘matrix suppression effect’ caused by ionic surface‐active compounds under fast‐atom bombardment (FAB) liquid secondary ion mass spectrometry (LSIMS) are being revised. It is shown that abundant transfer of the glycerol matrix molecules to the gas phase does occur under FAB‐LSIMS of ionic surfactants, contrary to popular belief. This process can be obscure because of the dependence of the charge state of the glycerol‐containing cluster ions on the type of ionic surfactant. It is revealed that, while glycerol matrix signals are really completely suppressed in the positive ion mass spectra of cationic surfactants (decamethoxinum, aethonium), abundant deprotonated glycerol and glycerol‐anion clusters are recorded in the negative ion mode. In the case of an anionic surfactant (sodium dodecyl sulfate), on the contrary, glycerol is completely suppressed in the negative ion mode, but is present in the protonated and cationized forms in the positive ion mass spectra. It is suggested that such patterns of positive and negative ion FAB‐LSIMS spectra of ionic surfactants solutions reflect the structure and composition of the electric double layer formed at the vacuum‐liquid interface by organic cations or anions and their counterions. Processes leading to the formation of the glycerol‐containing ions preferentially of positive or negative charge are discussed. The most obvious of them is efficient binding of glycerol to inorganic counterions of the salts Cl− or Na+, which is confirmed by data from quantum chemical calculations. The high content of the counterions and relatively small content of glycerol in the sputtered zone may be responsible for the charge‐selective suppression of neat glycerol clusters of opposite charge to the counterions. In the case of a mixture of cationic and anionic surfactants the substitution of inorganic counterions by organic ones was observed. The dependence of the exchange rate in the surface layer is not a linear function of the bulk solution concentration, and an effect of abrupt recharging of the surface can be registered. No both positively or negatively charged pure glycerol and glycerol‐inorganic counterion clusters are recorded for the mixture. Correlations between the mass spectrometric observations and some phenomena of surface and colloid chemistry and physics are discussed. Copyright © 2007 John Wiley & Sons, Ltd.
Oxygen‐18 measurement of Andalusian olive oils by continuous flow pyrolysis/isotope ratio mass spectrometry
Authors: Aramendía María A. , Marinas Alberto , Marinas José M. , Moreno José M. , Moalem Mustafa , Rallo Luis , Urbano Francisco J.
Published: January 2007

We report a method for the determination of δ18O isotopic abundance in olive oils. The results obtained by applying the method to various Andalusian oil samples obtained in the 2004/05 and 2005/06 seasons are discussed in relation to olive variety, geographical origin, climate and ripeness index. Application of the method to samples of assured varietal purity exposed the influence of olive variety and origin but not of the ripeness index. The δ18O values for the 2005/06 season are higher on average than those obtained in the colder 2004/05 season. Results obtained for samples of the Picual and Hojiblanca varieties in Córdoba and Málaga in the 2005/06 season suggest a correlation between enrichment in heavy isotopes and latitude whereas no clear‐cut effect of altitude was observed. Copyright © 2007 John Wiley & Sons, Ltd.
Making patient‐level estimates from medical encounter records using a multiplicity estimator
Authors: Burt Catharine W. , Hing Esther
Published: January 2007

The National Ambulatory Medical Care Survey (NAMCS) is a nationally representative survey of medical encounters in physician offices in the United States. Data from this survey and its counterpart in hospitals, the National Hospital Ambulatory Medical Care Survey (NHAMCS), have been used to investigate physician treatment and prescribing patterns. A limitation of these data, however, is that they represent visits rather than patients. Starting in 2001, the survey questionnaires began collecting information on the number of past visits the patient had to the sample provider during the one‐year period prior to the sampled visit. This information was used to estimate number of patients from the NAMCS and NHAMCS visit data using a multiplicity estimator. The resulting distribution of patients by the number of annual visits is similar to the distribution of persons in the U.S. making ambulatory care visits from a population‐based survey. This estimation technique may be useful in estimating patients with clinical characteristics that are difficult to collect from a population‐based survey. Published in 2007 by John Wiley & Sons, Ltd.
Screening for pre‐eclampsia and fetal growth restriction by uterine artery Doppler and PAPP‐A at 11–14 weeks' gestation
Authors: Pilalis A. , Souka A. P. , Antsaklis P. , Daskalakis G. , Papantoniou N. , Mesogitis S. , Antsaklis A.
Published: January 2007

Objective

To assess the role of maternal demographic characteristics, uterine artery Doppler velocimetry, maternal serum pregnancy‐associated plasma protein‐A (PAPP‐A) and their combination in screening for pre‐eclampsia and small‐for‐gestational age (SGA) fetuses at 11–14 weeks.

Methods

This was a prospective study of 878 consecutive women presenting for a routine prenatal ultrasound examination at 11–14 weeks. Pulsed wave Doppler was then used to obtain uterine artery flow velocity waveforms and the mean pulsatility index (PI) of the uterine arteries was calculated. Maternal serum samples for PAPP‐A were assayed. Along with maternal history, these measurements were compared in their ability to predict adverse outcome, defined as pre‐eclampsia and/or SGA and/or placental abruption.

Results

Mean uterine artery PI ≥ 95th centile and PAPP‐A ≤ 10th centile each predicted 23% of the women that developed pre‐eclampsia and 43% of cases of placental abruption. For SGA ≤ 5th centile, mean uterine artery PI ≥ 95th centile predicted 23% of cases and PAPP‐A ≤ 10th centile predicted 34%. Independent predictors for subsequent development of pre‐eclampsia were increased mean uterine artery PI ≥ 95th centile (OR, 2.76; 95% CI, 1.11–6.81) and maternal history of pre‐eclampsia/hypertension (OR, 50.54; 95% CI, 10.52–242.73). The predicting factors for SGA ≤ 5th centile were increased mean uterine artery PI ≥ 95th centile (OR, 2.0; 95% CI, 1.07–3.74) and low PAPP‐A (OR, 0.43; 95% CI, 0.20–0.93). Increased uterine artery PI was the only independent factor in the prediction of placental abruption (OR, 8.49; 95% CI, 2.78–25.94). The combination of uterine artery PI and maternal history of pre‐eclampsia/hypertension was better than was using uterine artery Doppler alone in predicting pre‐eclampsia. Similarly, for the prediction of SGA ≤ 5th centile, combining uterine artery Doppler and maternal serum PAPP‐A was better than was uterine artery Doppler alone. In both cases, the difference approached statistical significance.

Conclusions

The combination of maternal history with abnormal uterine artery Doppler and low PAPP‐A level at 11–14 weeks achieves better results than does either test alone in the prediction of pre‐eclampsia and SGA. Copyright © 2007 ISUOG. Published by John Wiley & Sons, Ltd.
Barley Protein Isolate: Thermal, Functional, Rheological, and Surface Properties
Authors: Mohamed Abdellatif , Hojilla‐Evangelista Mila P. , Peterson Steve C. , Biresaw Girma
Published: January 2007

Barley protein isolate (BPI) was extracted in 0.015 N NaOH in a 10:1 ratio solvent:flour and was precipitated by adjusting the pH to 4.5 and freeze‐dried. The thermal properties of BPI were determined using modulated differential scanning calorimetry (MDSC). BPI with 4% moisture content exhibited a glass transition (Tg) with 140 °C onset, 153 °C middle, and 165 °C end temperatures and a ΔCp of 0.454 J/g per °C. The high moisture content sample (50%) showed a Tg at 89, 91, or 94 °C and 0.067 ΔCp. Acetylation had no apparent effect on the foaming and emulsifying properties of protein from barley flour but exhibited the least‐stable foam among BPI samples. Foaming capacities of both barley protein isolates were ∼12% less than that of acid‐precipitated soy protein isolate reported in the literature. Acetylated BPI showed the highest surface hydrophobicity compared to the other samples. The surface‐tension test confirmed that unmodified and modified BPI possessed surface activity. BPI phosphorous oxycloride‐crosslinked was the most effective in lowering the surface tension of aqueous NaCl, while the crosslinked BPI was the least effective. The G′ value of BPI suspension was greater than G″ at all frequencies from 0.1 to 100 rad/s. The strain value at which linear behavior ceased and nonlinear behavior began ranged from 3 to 10%.
Thiazolidinediones exhibit different effects on preadipocytes isolated from rat mesenteric fat tissue and cell line 3T3‐L1 cells derived from mice
Authors: Mineo Hitoshi , Oda Chikako , Chiji Hideyuki , Kawada Teruo , Shimizu Kyoko , Taira Toshio
Published: January 2007

The effects of PPAR‐γ agonists, thiazolidinediones (TZDs), on preadipocytes isolated from rat mesenteric adipose tissue and murine cell line 3T3‐L1 were compared using an in vitro cell culture system. After each cell formed a confluent monolayer under appropriate medial conditions, pioglitazone or troglitazone was applied at 10 μM to each medium for cell maturation. We observed morphological changes in each cell, especially the accumulation of lipid droplets in the cytoplasm, during the culture periods. At the end of culture, DNA content, triglyceride (TG) content and glycerol‐3‐phosphate dehydrogenase (GPDH) activity were determined. Adiponectin concentrations in each culture medium were also measured during appropriate experimental periods. Application of TZDs increased the DNA content, TG accumulation and GPDH activity in the 3T3‐L1 cells but not in the mesenteric adipocytes. Although TG accumulation was unchanged, the number of lipid particles was decreased and the size of lipid particles in the mesenteric adipocytes was increased by TZD application. Although the TZDs increased adiponectin release from the 3T3‐L1 cells, adiponectin release from mesenteric adipocytes was suppressed (P < 0.05). Thus, the effects of TZDs differed between the primary culture of mesenteric adipose cells and the line cell culture of 3T3‐L1 cells. The source of adipocytes is an important factor in determining the action of TZDs in vitro, and particular attention should be paid when evaluating the effect of PPAR‐γ agonists on adipose tissues.
Induction of apoptosis in rat C6 glioma cells by panaxydol
Authors: Hai Jian , Lin Qi , Lu Yang , Zhang Hao , Yi Jing
Published: January 2007

Panaxydol is a naturally occurring non‐peptidyl small molecule isolated from the lipophilic fractions of Panax notoginseng, a well‐known Chinese traditional medicine. Previous studies have shown that panaxydol inhibited the growth of various kinds of malignant cell lines. To date, there has been no report concerning the effect of panaxydol on cell growth inhibition in glioma cells. In this paper, we examined panaxydol's antiproliferation and proapoptotic effects on rat C6 glioma cells and investigated its mechanism. Cell growth inhibition of panaxydol was determined by MTT reduction assay. Apoptosis of cells was measured by both Hoechst 33258 staining and Annexin V analysis. It was found that panaxydol markedly inhibited proliferation of C6 cells in a dose‐dependent manner with ID50 of 40 μM. The cell apoptosis was observed at 48 h in the presence of panaxydol. In concert with these findings, Western blot analysis showed a decreased expression of bcl‐2 and increased levels of Bax and caspase‐3 in C6 cells treated by panaxydol. In conclusion, panaxydol has profound effects on growth and apoptosis of C6 cells, suggesting that panaxydol may be a potential candidate for the treatment of malignant gliomas.
Antioxidant metabolism in Xenopus laevis embryos is affected by stratospheric balloon flight
Authors: Rizzo Angela M. , Rossi Federica , Zava Stefania , Montorfano Gigliola , Adorni Laura , Cotronei Vittorio , Zanini Alba , Berra Bruno
Published: January 2007

To test the effects of low levels of radiation from space on living organisms, we flew Xenopus laevis embryos at different stages of development on a stratospheric balloon (BI.R.BA mission). After recovery, different parameters were analyzed to assess the effects of flight, with particular regard to oxidative stress damage. Because of failed temperature control during flight, the flight shielded embryos (FC) could not be used for biochemical or morphological comparisons. In contrast, the incubation conditions (i.e. temperature, containers, volumes) for the flight embryos (F) were parallel to those for the ground controls. Mortality data show that younger embryos (16 h) flown on the balloon (F) are more sensitive to radiation exposure than older ones (40 h and 6 days). Exposure during flight lowered the antioxidant potential in all embryos, particularly older ones. These preliminary data demonstrate that flight on a stratospheric balloon might affect antioxidant metabolism, though it is not yet possible to correlate these results with low radiation exposure during flight.
Perception for ischemic pain shows similarities in adjustment disorder and major depression
Authors: Boettger M.K. , Bär K.J.
Published: January 2007

We recently described an increase of pain thresholds and tolerances for thermal and electrical pain in patients suffering from adjustment disorder (AD). Furthermore, we presented evidence that pain perception in major depressive disorder (MDD) depends on pain modality, with thresholds for ischemic pain being decreased compared to increased thermal and electrical pain thresholds.

Here, we investigated perception of experimentally induced ischemic pain in 15 patients suffering from AD (subtype with depressive symptoms) and controls matched for age and sex in order to examine whether a similar pattern of modality dependent pain perception can be established. Thresholds and tolerances were assessed on both sides of the body.

We found a significant decrease of ischemic pain thresholds in AD patients as compared to controls. Analogue findings have been reported for pain perception in MDD, therefore suggesting similarities with regards to pain perception in both disorders.

This adds weight to the assumption that depressive symptomatology might alter pain sensitivity in this subtype of AD since symptoms are milder, yet comparable to MDD.
A novel monoclonal antibody DC63 reveals that inhibitor 1 of protein phosphatase 2A is preferentially nuclearly localised in human brain
Authors: Kovacech Branislav , Kontsekova Eva , Zilka Norbert , Novak Pavol , Skrabana Rostislav , Filipcik Peter , Iqbal Khalid , Novak Michal
Published: January 2007

Abnormal phosphorylation of tau protein represents one of the major candidate pathological mechanisms leading to Alzheimer's disease (AD) and related tauopathies. Altered phosphorylation status of neuronal tau protein may result from upregulation of tau‐specific kinases or from inhibition of tau‐specific phosphatases. Increased expression of the protein inhibitor 1 of protein phosphatase 2A (I1PP2A) could therefore indirectly regulate the phosphorylation status of tau. As an important step towards elucidation of the role of I1PP2A in the physiology and pathology of tau phosphorylation, we developed a novel monoclonal antibody, DC63, which recognizes I1PP2A. Specificity of the antibody was examined by mass spectrometry and Western blot. This analysis supports the conclusion that the antibody does not recognize any of the other proteins of the 9‐member leucine‐rich acidic nuclear phosphoprotein family to which I1PP2A belongs. Immunoblot detection revealed that the inhibitor I1PP2A is expressed throughout the brain, including the hippocampus, temporal cortex, parietal cortex, subcortical nuclei and brain stem. The cerebellum displayed significantly higher levels of expression of I1PP2A than was seen elsewhere in the brain. Imunohistochemical analysis of normal human brain showed that I1PP2A is expressed in both neurons and glial cells and that the protein is preferentially localized to the nucleus. We conclude that the novel monoclonal antibody DC63 could be successfully employed as a mass spectrometry‐validated molecular probe that may be used for in vitro and in vivo qualitative and quantitative studies of physiological and pathological pathways involving I1PP2A.
The inhibitory binding site(s) of Zn2+ in cytochrome c oxidase
Authors: Francia Francesco , Giachini Lisa , Boscherini Federico , Venturoli Giovanni , Capitanio Giuseppe , Martino Pietro Luca , Papa Sergio
Published: January 2007

EXAFS identifies tetrahedral coordination site(s) for Zn2+ with two N‐histidine imidazoles, one N‐histidine imidazol or N‐lysine and one O–COOH (glutamate or aspartate), possibly located at the entry site of the proton conducting D pathway in the oxidase and involved in inhibition of the oxygen reduction catalysis and proton pumping by internally trapped zinc.
(+)‐Pinoresinol/(−)‐lariciresinol reductase from Linum perenne Himmelszelt involved in the biosynthesis of justicidin B
Authors: Hemmati Shiva , Schmidt Thomas J. , Fuss Elisabeth
Published: January 2007

A cDNA encoding a pinoresinol–lariciresinol reductase PLR (PLR‐Lp1) was isolated from a cell culture of Linum perenne Himmelszelt accumulating the arylnaphthalene lignan justicidin B. The recombinant PLR‐Lp1 prefers (+)‐pinoresinol in the first reaction step, but (−)‐lariciresinol in the second step. Therefore, it is the first PLR described with opposite enantiospecificity within the two reaction steps catalysed by PLRs. Hairy root lines transformed with an ihpRNAi construct to suppress plr gene expression show less mRNA accumulation for the plr‐Lp1 gene and PLR enzyme activity. Justicidin B accumulation was reduced down to 24% in comparison to control lines showing the involvement of PLR‐Lp1 in the biosynthesis of justicidin B.
Myosin 1E interacts with synaptojanin‐1 and dynamin and is involved in endocytosis
Authors: Krendel Mira , Osterweil Emily K. , Mooseker Mark S.
Published: January 2007

Myosin 1E is one of two “long‐tailed” human Class I myosins that contain an SH3 domain within the tail region. SH3 domains of yeast and amoeboid myosins I interact with activators of the Arp2/3 complex, an important regulator of actin polymerization. No binding partners for the SH3 domains of myosins I have been identified in higher eukaryotes. In the current study, we show that two proteins with prominent functions in endocytosis, synaptojanin‐1 and dynamin, bind to the SH3 domain of human Myo1E. Myosin 1E co‐localizes with clathrin‐ and dynamin‐containing puncta at the plasma membrane and this co‐localization requires an intact SH3 domain. Expression of Myo1E tail, which acts in a dominant‐negative manner, inhibits endocytosis of transferrin. Our findings suggest that myosin 1E may contribute to receptor‐mediated endocytosis.
MAPPIT analysis of TLR adaptor complexes
Authors: Ulrichts Peter , Peelman Frank , Beyaert Rudi , Tavernier Jan
Published: January 2007

Toll‐like receptors (TLRs) are crucial components of the innate immune system, coupling pathogen recognition to a cellular response. We used the MAPPIT mammalian two‐hybrid technique to investigate protein–protein interactions in the early steps in TLR signalling. A partial TLR‐adaptor interaction map was constructed confirming several known but also documenting novel interactions. We show that the TLR adaptor Mal is critical for linking Myeloid Differentiation primary response protein 88 (MyD88) to TLR2 and TLR4. Analysis of the contributions of the different sub‐domains of MyD88‐adaptor‐like protein (Mal) and MyD88 in adaptor homo‐ and hetero‐dimerisation provides an initial mechanistic insight in this bridging function of Mal.
A year in the life of an adolescent group
Authors: Akister Jane , Canever Nick
Published: January 2007

This paper describes experiences in starting and running a group for adolescents. It gives a brief review of the literature, describes our aims for the group, selection criteria, the initial sessions and how the group developed. It is particularly concerned to highlight the sorts of difficulties and dilemmas which face the leaders in starting and running a group. These problems include: (1) The composition of the group; (2) the structure of the meetings; (3) the style of leadership adopted; (4) the degree to which action techniques are used. In our out‐patient department adolescents were seen who seemed to need a “Social practice arena”. Adolescents whose responses were not grossly maladaptive and who needed a setting where they could experiment in peer relationship, air their views, and discuss issues such as difficulties with parents and where they would get feedback in these areas. The group discussed here was set up to try to meet these needs.
Mandalas and manipulators*
Authors: Allchin W.H.
Published: January 2007

The spirit of the times is characterized by widespread and various forms of violence and the increasing influence of the mass media, particularly TV. But it can be interpreted as part of a massive effort in Western culture, to explore and accept the hitherto unacceptable, namely the aggression and sexuality of human beings. However, the human psyche exhibits a capacity for creative orderliness as examplified by the mandalas. Examples are given from individual and group psychology of the activity of the archetypal patterns relevant to this development. The need to learn to work with this natural force is stressed, as well some consideration of ways in which conditions might be created to assist in its emergence.