bluuebunny/crossref_metadata_2025 huggingface dataset:
Expression of a novel alternatively spliced variant of NADP(H)‐dependent retinol dehydrogenase/reductase with deletion of exon 3 in cervical squamous carcinoma
Authors: Song Xu‐Hong , Liang Bin , Liu Ge‐Fei , Li Rui , Xie Jian‐Ping , Du Kun , Huang Dong‐Yang
Published: January 2007

NADP(H)‐dependent retinol dehydrogenase/reductase (NRDR) plays an important role in maintaining the homeostasis of retinoid. Aberrations in retinoid metabolism are considered as early events in carcinogenesis. We identified a novel alternatively spliced variant, NRDRB1, in HeLa cell and human cervical squamous carcinoma tissues, which is characterized by a complete deletion of exon 3. The latter resulted in changes in subcellular localization of NRDRB1 when compared with the peroxisomal localization of NRDR. To clarify the clinical significance of NRDRB1, we investigated its mRNA and protein expressions in normal cervical and cervical squamous carcinoma tissues, using RT‐PCR, quantitative real‐time PCR, Gateway expressing system, immunoprecipitation, immunoblotting, MALDI‐TOF mass spectrometry and immunohistochemistry. We detected NRDRB1 mRNA in 14 of 26 (53.9%) cervical cancer tissues, but in none of the 12 normal cervical tissues. NRDRB1 protein was expressed in NRDRB1 mRNA‐positive cases. While the full‐length NRDR mRNA was observed in both normal and neoplastic cervical tissues, its protein was only expressed in normal cervical epithelium. The results presented here provide evidence that metabolic disturbances of retinal and retinoic acid, due to abnormal splicing and functional disorder of NRDR, may be involved in cervical tumorigenesis. © 2007 Wiley‐Liss, Inc.
High grade cervical lesions are caused preferentially by non‐European variants of HPVs 16 and 18
Authors: Sichero Laura , Ferreira Silvaneide , Trottier Helen , Duarte‐Franco Eliane , Ferenczy Alex , Franco Eduardo Luis , Villa Luisa Lina
Published: January 2007

The intratypic variability of HPVs 16 and 18 has been extensively studied and has been used as an important tool in epidemiological studies of viral transmission, persistence and progression to clinically relevant cervical lesions. Infections by non‐European variants of HPVs 16 and 18 are associated with an increased risk for the development of high grade squamous intraepithelial lesions (HSIL). Our aim was to correlate the intratypic molecular variability of both HPV types and risk of persistent infection and lesion outcome in a cohort study conducted in Brazil. We characterized molecular variants of HPV types 16 and 18 by sequencing a fragment of the LCR, and of the E6 and L1 genes, for HPV‐16 variants only. For both types, European variants composed the most prevalent and diverse group. Persistent infections with HPV‐18 were associated with continuous detection of European variants. However, risk for simultaneous detection of HSIL and HPV DNA was higher in women harboring non‐European variants of HPV‐16. The same trend was observed with HSIL detected during follow‐up. Our study confirms the association between non‐European variants and risk of cervical neoplasia, and highlights the importance of their geographic distribution for cervical cancer risk assessment. © 2007 Wiley‐Liss, Inc.
Theoretical study and rate constant calculation for reaction of CF3CH2OH with OH
Authors: Wang Ying , Liu Jing‐Yao , Li Ze‐Sheng , Wang Li , Sun Chia‐Chung
Published: January 2007

The reaction mechanism of CF3CH2OH with OH is investigated theoretically and the rate constants are calculated by direct dynamics method. The potential energy surface (PES) information, which is necessary for dynamics calculation, is obtained at the B3LYP/6‐311G (d, p) level. The single‐point energy calculations are performed at the MC‐QCISD level using the B3LYP geometries. Complexes, with the energies being less than corresponding reactants and products, are found at the entrance and exit channels for methylene‐H‐abstraction channel, while for the hydroxyl‐H‐abstraction channel only entrance complex is located. By means of isodesmic reactions, the enthalpies of the formation for the species CF3CH2OH, CF3CHOH, and CF3CH2O are estimated at the MC‐QCISD//B3LYP/6‐311G (d, p) level of theory. The rate constants for two kinds of H‐abstraction channels are evaluated by canonical variational transition state theory with the small‐curvature tunneling correction (CVT/SCT) over a wide range of temperature 200–2000 K. The calculated results are in good agreement with the experimental values in the temperature region 250–430 K. The present results indicate that the two channels are competitive. Below 289 K, hydroxyl‐H‐abstraction channel has more contribution to the total rate constants than methylene‐H‐abstraction channel, while above 289 K, methylene‐H‐abstraction channel becomes more important and then becomes the major reaction channel. © 2007 Wiley Periodicals, Inc. J Comput Chem 28: 802–810, 2007
Generation of basis sets with high degree of fulfillment of the Hellmann‐Feynman theorem
Authors: Rico J. Fernández , López R. , Ema I. , Ramírez G.
Published: January 2007

A direct relationship is established between the degree of fulfillment of the Hellman‐Feynman (electrostatic) theorem, measured as the difference between energy derivatives and electrostatic forces, and the stability of the basis set, measured from the indices that characterize the distance of the space generated by the basis functions to the space of their derivatives with respect to the nuclear coordinates. On the basis of this relationship, a criterion for obtaining basis sets of moderate size with a high degree of fulfillment of the theorem is proposed. As an illustrative application, previously reported Slater basis sets are extended by using this criterion. The resulting augmented basis sets are tested on several molecules finding that the differences between energy gradient and electrostatic forces are reduced by at least one order of magnitude. © 2007 Wiley Periodicals, Inc. J Comput Chem 28: 748–758, 2007
The way of stabilizing non‐IPR fullerenes and structural elucidation of C54Cl8
Authors: Gao Xingfa , Zhao Yuliang
Published: January 2007

Recently, a new non‐IPR chlorofullerene C54Cl8 was isolated experimentally (Science 2004, 304, 699). To explore the ways to stabilize non‐IPR fullerenes, the authors studied all of the possible isomers of C54 fullerene and some of the C54Cl8 isomers at PM3, B3LYP/3‐21G, and B3LYP/6‐31G* levels. Combined with analysis of pentagon distributions, bond resonance energies, and steric strains, C54:540 with the least number of 5/5 bonds was determined to be the thermodynamically best isomer for the C54Cl8. Based on C54:540, the most probable structure of the experimental C54Cl8 was elucidated. The results suggested one of the necessary conditions of stabilizing non‐IPR fullerenes: chemical derivatizations of either endohedral complexation or exohedral addition need to sufficiently stabilize all of the kinetically unstable 5/5 bonds of the cages. © 2007 Wiley Periodicals, Inc. J Comput Chem 28: 795–801, 2007
Myoclonus–dystonia syndrome with severe depression is caused by an exon‐skipping mutation in the ε‐sarcoglycan gene
Authors: Misbahuddin Anjum , Placzek Mark , Lennox Graham , Taanman Jan‐Willem , Warner Thomas T.
Published: January 2007

We describe two affected individuals in a family with myoclonus–dystonia syndrome complicated with severe depression. One individual committed suicide. Molecular genetic analysis revealed a heterozygous point mutation in the ε‐sarcoglycan gene, which we show leads to skipping of exon 5. This report suggests that the psychiatric spectrum of MDS includes more severe depression. © 2006 Movement Disorder Society
Fatal encephalitis in a patient with refractory celiac disease presenting with myorhythmia and carpal spasm
Authors: Dimberg Elliot L. , Crowe Sheila E. , Trugman Joel M. , Swerdlow Russell H. , Lopes M. Beatriz , Bourne T. David , Burns Ted M.
Published: January 2007

We report the case of a woman with refractory celiac disease who developed abnormal spontaneous movements of the extremities and face consistent with myorhythmia. Investigation led to a diagnosis of encephalitis, confirmed by postmortem examination. The movements were likely caused by nonparaneoplastic encephalitis associated with refractory celiac disease. Etiologic and diagnostic considerations and treatment options are discussed. © 2006 Movement Disorder Society
Diagnostic indicators of restless legs syndrome in primary care consultations: The DESYR study
Authors: Crochard Anne , El Hasnaoui Abdelkader , Pouchain Denis , Huas Dominique , Arnulf Isabelle , Krieger Jean , Lainey Eric , Le Jeunne Philippe , Leger Damien , Schuck Stéphane , Texier Nathalie , Tison François , Montplaisir Jacques
Published: January 2007

The objective of this study is to determine whether spontaneous complaints about sleep or the legs could be used as potential indicators of restless legs syndrome (RLS) in primary care. A total of 351 general practitioners participated in the study. In a first historical patient identification phase, all patients with spontaneous complaints of sleep or leg symptoms over the previous year were identified. A control group without such complaints was identified. In a second prospective data collection phase, those who consulted a participating physician were interviewed to assess consensus diagnostic criteria of RLS. Severity was assessed with the International Restless Legs Syndrome Study Group severity rating scale. Of 1,405,823 patients consulting during the historical phase, a leg complaint was reported in 61,685 and a sleep complaint in 40,568. A total of 1,432 consulted during the prospective phase. A diagnosis of RLS was assigned to 42.6% of patients with leg complaints, 35.5% of those with sleep complaints, 54.9% of those with both complaints, and 12.9% of those with no complaints. Median RLS severity scores were 18.8 to 20.4. A total of 63.7% of patients were prescribed a venotonic, 43.7% a hypnotic, and 41.5% an anxiolytic. Complaints of sleep or leg symptoms are frequently associated with a diagnosis of RLS, and their presence should alert the physician to the possibility of a differential diagnosis of RLS. © 2006 Movement Disorder Society
Augmentation of restless legs syndrome with long‐term tramadol treatment
Authors: Vetrugno Roberto , La Morgia Chiara , D'Angelo Roberto , Loi Daniela , Provini Federica , Plazzi Giuseppe , Montagna Pasquale
Published: January 2007

Restless legs syndrome (RLS) augmentation, defined as a kind of suppression of the circadian rhythm of the disease in which sensory and motor symptoms appear earlier during the day (and over previously unaffected body parts), with a progressive phase advance until, backwards, the symptoms may cover the entire day, has been described only after treatment with dopaminergic drugs. We report clinical and polysomnographic accounts of a patient developing RLS augmentation after long‐term treatment with tramadol, an opioid agonist with selectivity for μ‐receptor and added norepinephrine and serotonin reuptake inhibition properties. Polysomnographic measures showed an improvement of RLS and a disappearance of diurnal sensory and motor RLS symptoms after tramadol was stopped. Our case confirms a recent retrospective report of augmentation of RLS after treatment with tramadol, and begs the question whether augmentation is truly restricted to dopaminergic drugs. © 2006 Movement Disorder Society
Exercise improves efficacy of levodopa in patients with Parkinson's disease
Authors: Muhlack Siegfried , Welnic Jacub , Woitalla Dirk , Müller Thomas
Published: January 2007

The objective was to investigate the impact of exercise on absorption and efficacy of levodopa (LD) in patients with Parkinson‘s disease (PD). A soluble, immediate release LD formulation was given followed by exercise near the aerobic limit on one day to PD patients, who underwent the same procedure only at rest on the second day. LD plasma behavior did not significantly differ between both conditions, but the motor response was significantly better 120 and 150 min after LD intake on the day with exercise than on the day with rest. Moderate exercise increases clinical efficacy of LD. © 2007 Movement Disorder Society
Triterpenoids from Eugenia grandis: structure elucidation by NMR spectroscopy
Authors: Manoharan Karuppiah Pillai , Song Fan Jing , Benny Tan Kwong Huat , Yang Daiwen
Published: January 2007

A new pentacyclic triterpenoid, 2α,3β‐dihydroxylup‐12‐en‐28‐oic acid (1) and a rarely encountered pentacyclic triterpenoid, 3β‐hydroxylup‐12‐en‐28‐oic acid (2), together with five known compounds, friedelin (3), 3β‐friedelinol (4), betulinic acid (5), oleanolic acid (6) and β‐sitosterol (7) were isolated from the chloroform extract of stem bark of Eugenia grandis (Syn: Syzygium grande). The structure and stereochemistry of the new compound (1) and the rarely encountered compound (2) were established by 1D and 2D NMR spectroscopic techniques. All the above isolated compounds from this plant are reported for the first time. Copyright © 2007 John Wiley & Sons, Ltd.
Joint pricing, assortment, and inventory decisions for a retailer's product line
Authors: Maddah Bacel , Bish Ebru K.
Published: January 2007

Consider a set of product variants that are differentiated by some secondary attributes such as flavor, color, or size. The retailer's problem is to jointly determine the set of variants to include in her product line (“assortment”), together with their prices and inventory levels, so as to maximize her expected profit. We model the consumer choice process using a multinomial logit choice model and consider a newsvendor type inventory setting. We derive the structure of the optimal assortment for some important special cases, including the case of horizontally differentiated items, and propose a dominance relationship for the general case that simplifies the search for an optimal assortment. We also discuss structural properties of the optimal prices. Finally, motivated by our analytical results, we propose a heuristic solution procedure, which is shown to be quite effective through a numerical study. © 2007 Wiley Periodicals, Inc. Naval Research Logistics, 2007
Construction of a bipotential for a multivalued constitutive law
Authors: de Saxcé G. , Buliga Marius , Vallée C. , Lerintiu C.
Published: January 2007

Bipotentials are non smooth mechanics tools, which allows modelling various non associative multivalued constitutive laws of dissipative materials (friction contact, soils, cyclic plasticity of metals, damage).

We answer the following question: given a graph M representing a material behaviour, is there a bipotential b for which M is the set of (x, y) such that b (x, y) = 〈x, y 〉? We state a simple necessary and sufficient condition for the existence of b. If it is fulfilled, we construct the bipotential. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Micromechanical strength analysis of fiber reinforced plastics
Authors: Ernst Gerald , Hühne Christian , Rolfes Raimund
Published: January 2007

Strength of an unidirectional lamina is computed with a representative volume element. An approximative “voxel” meshing method is used in conjunction with continuum damage mechanics to simulate crack growth in the RVE. Two material models for the nonlinear material behaviour of the epoxy resin are compared. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Unit‐cell simulations of damage and failure in PRMMCs
Authors: Ertürk Serkan , Reusch Frederik , Svendsen Bob
Published: January 2007

The purpose of this work is damage and failure modeling in multiphase metallic materials via unit‐cell simulations and homogenization methods. To this end, we investigate such behaviour in particle‐reinforced metal matrix composites (PRMMCs). Taking into account the processes of void nucleation (due, e.g., to particle debonding and/or cracking) and growth, we examine the effect of phase composition, particle sizes and distributions, as well as the nature of the particle/matrix interface, on damage and failure in the unit cell. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Numerical Simulation of Crack Growth
Authors: Hilgert Oliver , Schröder Jörg , Löblein Joachim
Published: January 2007

In recent years the X‐FEM based on the partition of unity method and the strong discontinuity approach (SDA) have shown to be powerful tools to model crack growth. Both methods model the crack surface by introducing additional d.o.f.. In the X‐FEM the nodes in the mesh around a crack are globally enhanced with new d.o.f. while in in the SDA the new d.o.f. are commonly introduced as internal ones. Thus the jump displacement fields are constant across elements. Therefore the d.o.f. can be condensed on element level which results in jumps in the displacement field at element edges. In this contribution the strong discontinuity approach is used approximating the displacement jump linearly across the crack length similar as e.g. in [3]. New additional nodes of the cracked elements that lie on the element edges are introduced but are not considered as internal nodes but remain global. Thus crack path continuity is automatically given. These global d.o.f. approximate the discontinuous part of the displacement field. The sum of the aforementioned part and the continuous displacement field represent the total displacement field including a possible jump. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Modelling of composite plates including damage
Authors: Kuczma Mieczysław , Kula Krzysztof
Published: January 2007

The paper is concerned with the modelling and numerical simulation of fibre‐composite plates in the nonlinear range due to large strains and damage. The layer‐wise approach is applied. Each layer is treated as elastic‐brittle and assumed to be orthotropic in the local material coordinate system. The appearance of damage is controlled according to the failure criteria [1,2,3,4]. When the failure condition is satisfied, the mechanical properties of the material are modified appropriately, depending on the type of damage (fibre breakage, matrix crack, fibre‐matrix shear). We have programmed the model as a user subroutine within the ABAQUS environment and carried out a number of numerical simulations. The obtained numerical results are compared with the experimental data available in the literature [3]. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
One fragmentation procedure for brittle material cracking
Authors: Reese S. H. , Wriggers P.
Published: January 2007

Realistic modeling of 3D fragmentation procedures with minimal incorporation of restrictions to the crack path is still a challenge in modern computational engineering simulations. The presented approach is used to model failure and cracking in concrete structures, applying an explicit finite element integration scheme. Within this model the Strong Discontinuity Approach (SDA) is used to handle the failure process until the material is fully damaged. At stage an adaptive refinement technique is incorporated in ordner to introduce real cracks which are suitable for DEM / FEM coupling or contact formulations. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
An Approach for Micromechanical Modelling of Damage Mechanisms
Authors: Timmel Mario , Kaliske Michael , Kolling Stefan
Published: January 2007

In the framework of numerical simulation of damaged materials, softening behaviour represents an important topic. Thereby, the decrease of stiffness is mainly caused by the evolution of microvoids. In contrast to the established phenomenological damage approaches, the explicit consideration of effects on the micro scale can lead to an improved approximation quality. In this work, we discuss an approach to describe microstructural evolution. Based on a two phase micro model representing the macroscopical material behaviour, the structural evolution on the micro scale will be modelled based on configurational forces. Besides some theoretical basics on configurational forces at two phase systems and the definition of suitable evolution laws, we present an application of this approach on void growth process in rubberlike material. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Longitudinal track‐structure interaction on railway bridges
Authors: Birk Carolin , Ruge Peter
Published: January 2007

In this paper, a computational model for the correct simulation of an arbitrary sequence of longitudinal loading cases on coupled track‐bridge systems is proposed. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Partially connected composite beams
Authors: Kuczma Mieczysław , Kuczma Bożena
Published: January 2007

Analytical solutions to some boundary value problems for a steel‐concrete composite beam with deformable shear connectors in the elastic range are presented. The obtained results show that the distribution of slip on the bond interface between the concrete slab and the steel girder is not a monotone function, even in the case of uniform loading on the composite beam. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Modelling of the frictional heating generated in rolling contact
Authors: Pauk Volodymyr , Zastrau Bernd W.
Published: January 2007

The transformation of the frictional energy into the heating is a problem of continued technical interest. This problem in the case of the pure sliding contact is widely discussed in many papers. In the case of rolling contact, the frictional heating is due to the slip between the rollers. Since the value of slip is unknown, the problem is more complicated, it becomes non‐linear. The paper presents a new mathematical model of the generation of the heat during the rolling problem. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
An efficient strategy to lifetime calculations of large structures
Authors: Rickelt Christian , Reese Stefanie
Published: January 2007

The objective of this contribution is to present two single aspects of our efficient strategy to life cycle calculations of large structures. According to the assumption that only some segments of a structure require a non‐linear analysis the entire system is strictly decomposed into linear and non‐linear subsystems. To increase the efficiency further the number of degrees‐offreedom of the linear parts are treated by model reduction techniques. Three different methods are depicted and compared. To simulate the growth of damage an isotropic continuum damage model for ductile damage phenomena of metals under consideration of large inelastic strains is presented. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A comparison of nonlinear beam finite element formulations
Authors: Sänger N. , Betsch P.
Published: January 2007

Two alternative nonlinear finite element formulations emanating from the Simo‐Reissner beam theory are considered. The orientation of the beam cross section is characterised by a director frame which can be either represented by means of rotational parameters or the direction cosine matrix. In the planar case the use of a single angle can be considered as the canonical formulation. The corresponding finite element approximation relies on the interpolation of the nodal angles. However, the extension of this approach to the three‐dimensional case is nontrivial and often leads to element formulations beeing not frame‐indifferent. On the other hand, the interpolation of the nodal direction cosines in general yields frame‐indifferent element formulations [1, 2]. The present talk focuses on a comparison of the two aforementioned finite element beam formulations for planar problems. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Remarks on a Least Squares Mixed Finite Element for Plane Elasticity
Authors: Schwarz Alexander , Schröder Jörg
Published: January 2007

The objective of this work is to discuss a least squares finite element method within plane elasticity problems. The L 2‐norm minimization of the residuals of the given first order system of differential equations leads to a functional, which is a two field formulation in the displacements and the stresses. The governing equations for the considered least squares mixed finite element are derived. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Determining Mechanical State of the Body – Multilayer Coating System
Authors: Shevchuk Victor A.
Published: January 2007

This paper suggests an effective approach, essentially simplifying determining mechanical state of bodies with thin multilayer coatings. It is based on the modeling of such coatings by thin shells with appropriate geometrico‐mechanical properties of a coating. In such an approach, the influence of thin coatings on the mechanical state of the body ‐ multilayer coating system is described by special generalized boundary conditions. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Study on the thermo‐mechanical behavior of superelastic NiTi wires
Authors: Vishnevsky Andrey , Lammering Rolf
Published: January 2007

The strong coupling of thermal and mechanical properties and the highly inhomogeneous strain distribution in tensiontests motivate for thorough investigations on NiTi shape memory alloys. For these tests a complex experimental set‐up has been developed which allows for the simultaneous measurement of stress, strain, and temperature with high spatial and temporal resolution. The experimental results show the influence of strain rate, number of cycles, and deformation level on the progress of stress induced phase transformation in the specimens. A critical evaluation of the experimental results in view of a potential constitutive modeling is given. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A constitutive model for polymers with a piecewise linear yield surface
Authors: Vogler M. , Kolling S. , Haufe A.
Published: January 2007

Reliable prediction of the behaviour of structures made from polymers, especially under high dynamic loading, is a topic under considerable investigation in engineering practice. A constitutive model is derived including important phenomena like necking, crazing and strain rate dependency. In particular, different yield surfaces in compression and tension are taken into account using a piecewise linear formulation. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Freie Zielanfahrt
Authors: Barthels Pierre , Wauer Jörg
Published: January 2007

Von “freier Zielanfahrt” spricht man in der Fördertechnik, wenn der Bewegungsablauf von Förder‐ und Hebezeugen (z.B. Gabelstapler) durch einen Menschen gesteuert wird und die Bewegung somit vorgegeben aber zufällig ist. Die hierbei auftretenden Transversalschwingungen der teleskopierbaren Segmente des Mastes reduzieren die Leistungsfähigkeit der Maschine und führen zu Sicherheitsproblemen. Dieser Beitrag befasst sich mit der Schwingungsunterdrückung bei solchen Systemen, wobei eine dem jeweiligen Systemzustand entsprechend geregelte Kraft auf das unterste Segment des Mastes aufgebracht wird. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
On modelling and analysis of gear drives with nonlinear couplings
Authors: Byrtus Miroslav , Zeman Vladimír
Published: January 2007

The paper deals with modelling of vibration of shaft systems with gears and rolling‐element bearings using the modal synthesis method with DOF number reduction. The influence of the nonlinear bearing and gearing contact forces with the possibility of the contact interruption is respected. The gear drive nonlinear vibrations caused by internal excitation generated in gear meshing, accompanied by impact and chaotic motions are studied. The theory is applied to a simple test‐gearbox. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Bi‐harmonically excited pendulum: shifted resonances and quenching the low frequency excitation
Authors: Fidlin A.
Published: January 2007

The effect of the harmonic high‐frequency vibration of the suspension point on a mathematical pendulum is well known [1]. It can be described as stiffening/softening or stabilization/destabilization of the up‐pointing and down‐pointing equilibriums for pure vertical or pure horizontal excitation. If the excitation is tilted the effect of biasing appears in addition [2]. The effects of bi‐harmonic excitation are more complex. Two of them are discussed in the recent paper. The first one occurs if one of the excitation frequencies is high and another one is low. Then the so called shifted or conjugated resonances can be observed [3]. The second one takes place if the two excitation frequencies are high but their difference is small (slowly modulated high‐frequency excitation according to [4]). It is shown that in that case it is possible to choose the bi‐harmonic excitation in order to quench the resonance of the pendulum without changing its basic frequency. The analysis is fulfilled both for the external and parametric excitations. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Neufassung und Anwendung einer nichtlinearen Seiltheorie
Authors: Heinen Anton , Thalheim Jens‐Uwe
Published: January 2007

Vorgestellt wird eine neugefasste, geometrisch nichtlineare Seiltheorie (siehe auch [1]), die der klassischen Theorie [2] mechanisch gleichwertig ist, aber einfachere Nichtlinearitäten aufweist und daher numerische Vorteile bietet. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Vibrations of linear structures with spatial local nonlinearities
Authors: Heuer Rudolf
Published: January 2007

Classical Modal Analysis can be applied to linear systems if the corresponding damping matrix is proportional to the mass or/and stiffness matrices. Otherwise, e.g., in case of structures with single external damping devices, an alternative or approximate solution procedure for determining the dynamic response has to be chosen, compare [1]–[3]. Vibration problems of linear structures with spatially localized nonlinearities are related to those non‐classically damped systems. Such systems are characterized by the fact that their nonlinear behavior is largely restricted to a limited number of single points in the structure. The objective of this paper is to present an approximate semi‐analytical procedure for analyzing the steady‐state harmonic response of those locally nonlinear structures, where special emphasis is laid on beams with single nonlinear devices. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Bifurcation Behavior of a 1DOF Sliding Friction Oscillator
Authors: Schwarzer Daniel , Hetzler Hartmut , Seemann Wolfgang
Published: January 2007

This article deals with different types of friction models and their influence on the behavior of a simple 1 degree‐of‐freedom (DOF) sliding friction oscillator which is in literature commonly referred to as “mass‐on‐a‐belt”‐oscillator. The examined friction characteristics are assumed to be proportional to the applied normal force and only dependend on the relative velocity between the mass and the belt. For an exponential and a generalized cubic friction characteristic, the linear stability of the steady‐state and the bifurcation behavior in the sliding domain are examined. It is shown that the resulting phase plots of the observed system are strongly dependent on the chosen friction characteristic. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Dynamics of an Euler Elastica Pipe with Internal Flow of Fluid
Authors: Stangl Michael , Irschik Hans
Published: January 2007

The equations of motion for a cantilever Euler elastica pipe are deduced applying a generalized set of Lagrange equations for non‐material volumes. Based on an exact planar nonlinear beam theory the strain energy for the pipe is derived. The classical Lagrange terms and the additional terms due to moving mass entering and exiting the system result in a set of nonlinear equations of motion for the cantilever pipe with internal flow. A possible dimensional reduction and comparison to existing works are performed. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Bifurcations of Stick‐Slip‐Separation Waves in a Brake‐like System
Authors: Steindl Alois
Published: January 2007

We consider a system composed of an elastic tube in frictional contact with a rotating rigid cylinder. At the contact surface several types of rotating slip‐stick and also slip‐stick‐separation waves with different wave numbers can be observed. In order to determine the stability of these travelling waves, we have to solve a non‐local eigenvalue problem. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Maximum friction law in plasticity
Authors: Alexandrov Sergei
Published: January 2007

The maximum friction law postulates that the friction stress is equal to the maximum possible shear stress admissible by the constitutive equations. The boundary value problems including the maximum friction stress as a boundary condition reveal special mathematical features which are of interest in the development of theories and models, numerical simulation and engineering applications. The present paper shortly reviews the singularity in velocity fields that can occur in the vicinity of maximum friction surfaces. A large class of rigid plastic (in a broad sense that the elastic portion of the strain rate tensor is neglected) is considered. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Identifikation von Materialparametern anhand inhomogener Versuche
Authors: Besdo D. , Hohl C. , Ihlemann J.
Published: January 2007

Für die Anwendung von Stoffgesetzen benötigt man einen sicheren Weg, um die im Stoffgesetz enthaltenen Parameter zu bestimmen. Dazu werden Messungen des entsprechenden Materials benötigt, die sicher und reproduzierbar durchgeführt werden können. Dabei kann es von Vorteil sein, nicht nur die üblichen homogenen Messmethoden zu verwenden, sondern diese Beschränkung für Versuche aufzugeben, die dafür klare Randbedingungen aufweisen und einfach zu messen sind. Es wird eine Methode aufgezeigt, mit der auch für solche Versuche Parameter identifiziert werden können, indem die kommerzielle FEM‐Software ABAQUS zur Simulation der (inhomogenen) Versuche benutzt wird. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Boundary element method for dynamic inelastic analysis
Authors: Czyż Tomasz , Fedelinski Piotr
Published: January 2007

The paper shows formulation and application of the boundary element method (BEM) for dynamic analysis of elastoplastic materials. The initial stress approach is used in the elastoplastic analysis. The mass matrices are computed by the dual reciprocity method (DRBEM). Displacements and stresses are computed by the iterative procedure in each time step. The time dependent problem is solved by the direct integration Houbolt method. The methods presented in the paper are applied to compute displacements and stresses in a crank loaded by dynamic forces. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
An Approach to the Modeling of Physical Ageing in Rubbery Polymers
Authors: Dal Hüsnü , Kaliske Michael
Published: January 2007

The oxidation reactions responsible for physical ageing are thermally activated processes and yield cross‐linking similar to the vulcanization process and chain‐scission reactions. Chain scission, is responsible for the relaxation behaviour under constant stretch, whereas cross‐linking is responsible for hardening of the material. The decrease in the stretch at break upon cross‐linking motivates the so called network alteration proposed in this contribution. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A generalized polyconvex hyperelastic model for anisotropic solids
Authors: Ehret Alexander E. , Itskov Mikhail
Published: January 2007

A generalized polyconvex hyperelastic model for anisotropic solids is presented. The strain energy function is formulated in terms of convex functions of generalized invariants and is given by a series with an arbitrary number of terms. The model addresses solids with orthotropic or transversely isotropic material symmetry as well as fiber‐reinforced materials. Special cases of the strain energy function suitable for anisotropic elastomers and soft biological tissues are proposed. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Non‐local modeling of thermomechanical localization in metals
Authors: Flatten Arnd , Klingbeil Dietmar , Svendsen Bob
Published: January 2007

The purpose of this work is to compare and contrast two different modeling approaches for high‐speed, dynamic loading of metals. A so‐called “local” model including hardening, strain‐rate hardening as well as temperature and ductile damage softening behaviour is extended by gradient plasticity. In particular, both models are compared in the context of their application to the modeling and simulation of dynamic shear‐banding in the alloy Inconel 718. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Multidimensional Tests of Superelastic, Polycristalline NiTi under Isothermal Conditions
Authors: Grabe Christian , Bruhns Otto T.
Published: January 2007

Different isothermal and non‐isothermal tension/torsion tests are conducted on hourglass‐shaped, superelastic NiTi specimens. A new measurement device based on inductive displacement transducers is presented allowing for a directly decoupled measurement of twist and elongation at the same measuring points within the gage length. Thus, not only measuring but also controlling the deformation of the specimen is possible. The specimen temperature is actively controlled to keep the temperature deviation as low as possible and to be able to react immediately to sudden changes in the temperature field due to latent heat generation/absorption during phase transitions. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Modellierung und Simulation thermomechanischer Kopplungsphänomene
Authors: Helm Dirk
Published: January 2007

MetallischeWerkstoffe zeigen insbesondere bei großen Deformationen und hohen Deformationsgeschwindigkeiten stark ausgeprägte thermomechanische Kopplungsphänomene. Zur Beschreibung dieser Kopplungsphänomene wird ein Materialmodell der finiten Thermoviskoplastizität vorgestellt. In dem Modell wird die Annahme verwendet, dass die viskoplastischen Deformationen isochor sind. Das entwickelte Modell ist in der Lage, die wesentlichen experimentellen Beobachtungen zu beschreiben. Zur numerischen Lösung thermomechanisch gekoppelter Anfangs–Randwertaufgaben wird die Methode der finiten Elemente verwendet. Die hierbei erforderliche numerische Integration der Konstitutivgleichungen erfolgt unter Verwendung eines in [5] entwickelten Integrationsoperators: Dieser Integrationsoperator besitzt die Eigenschaft, dass die Unimodularität der Integrationsvariablen für beliebige Zeitinkremente erhalten bleibt. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Adaptivity in the context of high speed cutting
Authors: Hortig Christian , Svendsen Bob
Published: January 2007

The purpose of this short work is the thermomechanical modeling of shear band and chip formation during high‐speed cutting. Shear bands develop in areas of maximal mechanical dissipation in which temperature‐dependent softening dominates strainand strain‐rate‐dependent hardening. In the simulations, the well‐known problem of the mesh‐dependence of the shear‐band development is addressed, involving both mesh size and mesh orientation. An example simulation is presented. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Inconsistencies in Plane‐strain Elasto‐plastic Rolling Simulations
Authors: Kainz Alexander , Krimpelstaetter Konrad , Zeman Klaus
Published: January 2007

Plane strain conditions are frequently used as model assumptions for the approximate calculation of flat rolling processes for sufficiently wide strips. This means that during the entire forming process, the strain rate in strip width direction (z‐direction) remains zero. In the case of elasto‐plastic material, the transitions from elastic to plastic states and vice versa are of particular interest. If we accept the flow rule of Levy‐Mises, the normal stress σzz equals the average value of the normal stresses σxx and σyy inside plastic domains. Using Hooke's law we obtain a different relation for σzz in elastic domains. At transition points from elastic to plastic domains and vice versa, above relations for σzz have to be fulfilled simultaneously. Generally, this yields a discontinuous behaviour of σzz at the transition points and consequently to discontinuities of the stress σyy as well as the strains εzz and εyy, provided a continuous behaviour of σxx in rolling direction is postulated. The resulting discontinuity of εzz indicates therefore an inconsistency of such a plane strain model. Some key aspects of the underlying theory and consequences of such model assumptions will be pointed out. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Analysis of stress and strain in tension cylindrical sample
Authors: Malag Leszek , Kukielka Leon
Published: January 2007

One of the basic engineering problem occurring during the numerical analysis is to define the function of yield stress of material in the real conditions of a technological process. These properties are necessary to calculate the deformation and the state of stress and strain in the surface layer of an object. An inappropriate selection of the mechanical properties of the material is the reason of the occurrence of errors in numerical calculations of a continuous object, considered as a boundary and initial problem. Scientific investigations are being conducted with the aim to develop a database concerning yield stresses for different metals, depends on complex conditions of thermo‐dynamical loads, e.g. temperature, the equivalent of the strain and the strain rate. The article presents a method of the determination of this dependence while using an experimental and numerical analysis. During the model investigations on the INSTRON testing machine, the force of elongation of the sample is measured and then calculations are made of the displacement of nodes of finite elements, plotted on outside surface of sample. The process is considered as a multi nonlinear problem. For this reason, an incremental method of motion and deformation of solid in an updated Lagrange formulation is used. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Modelling of composites with a space‐varying microstructure
Authors: Woźniak Cz. , Michalak B. , Woźniak M.
Published: January 2007

The object of analysis is a microheterogeneous rigid heat conductor with apparent properties smoothly varying along the preferred direction. The aim of this contribution is to formulate two macroscopic models of this conductor. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
When to start supplementary iron to prevent iron deficiency in early childhood in sub‐Saharan Africa setting
Authors: Rahimy Mohamed Cherif , Fanou Lionnelle , Somasse Yassinme Elysee , Gangbo Annick , Ahouignan Gilbert , Alihonou Eusebe
Published: January 2007

Background

To study the efficacy of oral ferrous fumarate, an inexpensive, readily available preparation on iron deficiency in infants in Africa.

Procedure

Four months old (group 1, n = 252) and 6–18 months old (group 2, n = 360) healthy infants attending four primary health care centers (PHC) for vaccination/well‐child visits in Benin were studied. Ninety‐six pregnant women (PW) over 36 weeks gestational age attending the same PHC during the study period were also studied. Infants were offered 2 months supplementation with oral powdered generic ferrous fumarate (GFF), that is, 5 mg/kg/day of elemental iron, given twice and were reevaluated 2 months later for hematological indices. The prevalence of anemia and iron deficiency among pregnant women was assessed using hematological indices and transferrin saturation.

Results

The prevalence of anemia was 42.0%, 61.9%, and 37.5% in groups 1, 2, and PW, respectively. All anemic PW were iron deficient. Hemoglobin level shifted towards high values after supplementation. In addition, 24 infants from group 1 whose mothers interrupted the treatment, showed a significant decrease in hemoglobin level values, and similar improvement after two additional months of supplementation.

Conclusion

Programs to prevent iron deficiency in Africa should utilize inexpensive preparations, start during pregnancy, continue in infants at 3 months of age and address problems of noncompliance. Pediatr Blood Cancer 2007;48:544–549. © 2007 Wiley‐Liss, Inc.
Incidence of childhood cancer in Switzerland: The Swiss childhood cancer registry
Authors: Michel G. , von der Weid N.X. , Zwahlen M. , Redmond S. , Strippoli M‐P.F. , Kuehni C.E. ,   For the Swiss Paediatric Oncology Group (SPOG)
Published: January 2007

Background

This report describes the incidence of childhood cancer in Switzerland, based on the data from the Swiss Childhood Cancer Registry (SCCR), a national hospital‐based cancer registry with very high coverage, founded in 1976 by the Swiss Paediatric Oncology Group (SPOG).

Procedure

Malignancies were coded according to the International Classification of Childhood Cancer (ICCC‐3). Incidence rates per 100,000 person‐years were calculated for all malignancies and groups of malignancies in Swiss residents less than 15 years of age for the decade 1995–2004.

Results

The SCCR annually registered on average 174 new cases of cancer in Swiss residents aged <15 years, with a median age at diagnosis of 5.6 years. The crude incidence of childhood cancer in children aged <15 years was 13.5, higher for boys (15.0 per 100,000) than for girls (12.1 per 100,000), and was nearly twice as high in the first 5 years of life (19.3 per 100,000) than in the age group 5 to 14 years (10.8 per 100,000).

Conclusion

Incidence of childhood cancers in the SCCR was similar to neighbouring countries and to data published by regional cancer registries in Switzerland for the same period, suggesting good completeness of registration. This makes the SCCR a valuable resource for national and international research on childhood cancer. Pediatr Blood Cancer 2008;50:46–51. © 2007 Wiley‐Liss, Inc.
Facile synthesis of poly(hydroxyethyl acrylate) by frontal free‐radical polymerization
Authors: Chen Su , Hu Ting , Tian Yuan , Chen Li , Pojman John A.
Published: January 2007

We report the first synthesis of poly(hydroxyethyl acrylate) (PHEA) without solvent by free‐radical frontal polymerization (FP) at ambient pressure. In a typical run, the appropriate amounts of reactant (hydroxyethyl acrylate) and initiator (1,1‐di(tert‐butylperoxy)‐3,3,5‐trimethylcyclohexane) (Luperox 231) were mixed together at ambient pressure. FP was initiated by heating the wall of the tube with a soldering iron, and the resultant hot fronts were allowed to self‐propagate throughout the reaction vessel. Once initiated, no further energy was required for polymerization to occur. To study the macrokinetics, we also produced PHEA frontally with ammonium persulfate as initiator and dimethyl sulfoxide as the solvent. The dependences of the front velocity and front temperature on the initiator concentration and reactant dilution were investigated. The front temperatures were between 124 and 157 °C, depending on the ammonium persulfate concentration. Thermogravimetric analysis indicates that PHEA prepared by FP with ammonium persulfate as initiator had higher thermal stability than solvent‐free frontally prepared PHEA with Luperox 231 as initiator. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 873–881, 2007