bluuebunny/crossref_metadata_2025_split huggingface dataset:
Role of Polymorphisms in Adamantiades-Behçet’s Disease
Authors: KAKLAMANI VIRGINIA G. , SADIM MAUREEN , KOUMANTAKI YVONI , KAKLAMANIS PHEDON , PASCHE BORIS 
Published: December 2008

ObjectiveWe previously showed that Adamantiades-Behçet’s disease (A-BD) is associated with a lower incidence of malignancy compared with the general population. Transforming growth factor-β (TGF-β) has been shown to play a role in cartilage regeneration and is increased in patients with A-BD. We also found 2 functional polymorphisms of the TGF-β pathway, TGFBR1*6A and TGFB1*CC, that are associated with risk of malignancy. We tested whether incidence of these polymorphisms would differ in patients with A-BD compared with healthy controls of similar age and geographic location.MethodsWe performed a case-control study including 139 cases and 128 controls from Greece. Cases and controls were genotyped for TGFBR1*6A and TGFB1*CC.ResultsWe found that cases had lower incidence of TGFBR1*6A compared with controls (11.3% vs 13.3%, respectively). Also, the incidence of TGFB1*CC was lower in cases than controls (24.6% vs 27.0%, respectively). These differences were not statistically significant.ConclusionAlthough there is a suggestion that the lower incidence of TGFBR1*6A in A-BD patients may play a protective role against development of malignancy, larger studies would be needed to fully evaluate the role of TGF-β and its polymorphisms in A-BD.
Ribonucleotide Reductase: Recent Advances
Authors: Stubbe JoAnne , Cotruvo Joseph A 
Published: December 2008

AbstractRibonucleotide reductases (RNRs) catalyze the conversion of nucleotides to deoxynucleotides and play an essential role in nucleic acid metabolism in all organisms. RNRs have been divided into three classes. They share a structurally homologous subunit where the reduction occurs, with the chemistry being initiated by thiyl radical‐mediated abstraction of the nucleotide's 3′‐hydrogen atom. The classification of RNRs is based on the different strategies used to generate the transient thiyl radical. The class Ia and Ib RNRs use a diferric‐tyrosyl radical cofactor, the class II RNRs use adenosylcobalamin, and the class III RNRs use a glycyl radical generated by a [4Fe4S]1+cluster andS‐adenosylmethionine. This article focuses on the recent advances in our understanding of thein vitroandin vivomechanisms of formation of the metallocofactors in the class I RNRs inE. coliandS. cerevisiae. The discovery of a new class of RNR, class Ic, whose active cofactor is proposed to be an MnIVFeIIIcluster, and a summary of recent insights into the chemistry of the novel cofactor are also described. Finally, the current understanding of the unprecedented role of the metallocofactor in radical propagation over 35 Å in the class Ia—and presumably class Ib and Ic—RNRs is presented.
Acetylene Hydratase
Authors: Seiffert Grazyna B , Abt Dietmar , tenBrink Felix , Fischer David , Einsle Oliver , Kroneck Peter MH 
Published: December 2008

AbstractThe tungsten‐iron‐sulfur enzyme acetylene hydratase is a rather unique enzyme within the class of tungsten/molybdenum enzymes in the sense that it catalyzes a nonredox reaction, the addition of one molecule of water to the CC bond of acetylene to form acetaldehyde. Its crystal structure (1.26 Å) reveals a close to octahedral, or trigonalantiprismatic tungsten center, which binds a water molecule that gets activated by an adjacent aspartate residue such that it can attack an acetylene molecule bound in a distinct, hydrophobic pocket. This requires a strong shift of pKaof the aspartate, caused by a nearby low‐potential [4Fe–4S] cluster. To gain access to this novel W‐Asp‐active site, the protein evolved a new substrate channel distant from where it is found in other molybdenum and tungsten enzymes.
One‐Step Process for Creating Triple‐Shape Capability of AB Polymer Networks
Authors: Behl Marc , Bellin Ingo , Kelch Steffen , Wagermaier Wolfgang , Lendlein Andreas 
Published: December 2008

AbstractTriple‐shape polymers can move from a first shape (A) to a second shape (B) and from there to a third shape (C), where both shape changes are induced by temperature increases. This triple‐shape capability is obtained for multiphase polymer networks after application of a complex thermomechanical programming process, which consists of two steps; these steps create shapes (B) and (A), while shape (C) is defined by the covalent crosslinks of the polymer network. Here, the creation of the triple‐shape capability for an AB polymer network system by a simple one‐step process similar to a conventional dual‐shape programming process is reported. The polymer networks are based on poly(ε‐caprolactone) (PCL) and poly(cyclohexyl methacrylate); favorable compositions for obtaining a triple shape effect have a PCL content between 35 and 60 wt%. This finding substantially facilitates handling of the triple‐shape technology and is an important step toward the realization of potential applications in which more than one shape change is required.
Strategy for spatial simulation of co‐rotating vortices
Authors: Deniau H. , Nybelen L. 
Published: December 2008

AbstractThe present numerical study is motivated by the challenge to simulate the three‐dimensional spatial dynamics of a co‐rotating vortex system, through the development of an elliptic instability (C. R. Phys. 2005; 6(4–5):431–450) using a high‐order solver of the compressible Navier–Stokes equations. This phenomenon was studied previously only by temporal simulations. The interest of spatial simulation is first to analyse the effect of the axial velocity on the merging process, which are neglected with the temporal approach, and to study interaction with jet flows. The numerical problem is the choice of boundary conditions (BCs): for the inflow and outflow conditions as well as for the lateral BCs to represent a fluid at rest. Special attention will be paid to the latter because the difficulties come from the non‐zero circulation of the vortex system considered. The classic BCs of Poinsot and Lele (J. Comput. Phys. 1992; 101: 104–129) based on the characteristics wave approach have been modified to be more adapted to the physics considered here. This new BC is based on the assumption of an irrotational flow close to the borders (in order to determine the magnitude of the waves), as the vorticity field is concentrated on the computational domain centre where the vortex system is initially placed. After a validation of these improved BCs and of all numerical tools used such as selective artificial dissipation, two spatial simulations of the vortex breakdown phenomenon have allowed validating our solver for a three‐dimensional case by comparison with the results of Ruith et al. (J. Fluid Mech. 2003; 486:331–378). Thus, the merging process of equal co‐rotating vortices through the development of elliptic instability with axial velocity were simulated. Three vortex flow configurations were considered with different vortex systems and velocity peaks ratio (azimuthal and axial velocities).A numerical tool has been elaborated and validated for the simulation of spatial instability development in vortex flows. The first results show this ability, and the influence of the axial velocity on the dynamics of the instabilities. However, spatial simulations are limited by the computational resources (linked to the resolution and axial domain length to capture the merging process) and restricted to academic vortex flow configuration. Copyright © 2008 John Wiley & Sons, Ltd.
Thermodynamic consistent modelling of defects and microstructures in ferroelectrics
Authors: Müller Ralf , Schröder Jörg , Lupascu Doru C. 
Published: December 2008

AbstractThe paper describes the main phenomena associated with fatigue in ferroelectricmaterials due to defects and microstructural effects. An analysis the modelling on different length scales is presented. Starting from a thermodynamic analysis of the macroscopic material behavior other microscopic aspects are addressed. The introduction of an orientation distribution function allows for a computationally efficient extension of a single crystal model to realistic 3D structures. Additionally, the thermodynamic treatment of defects and domain wall motion is discussed to provide a better understanding of various micro‐mechanisms. It is explained by the concept of configurational/driving forces, how defects influence each other and how the mobility of domain walls is reduced in the presence of defects. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Computational modelling of microcracking effects in polycrystalline piezoelectric ceramics
Authors: Utzinger Johannes , Steinmann Paul , Menzel Andreas 
Published: December 2008

AbstractPiezoelectric ceramics nowadays are widely commercialised in various fields of engineering technology and related constitutive modelling approaches constitute an active field of research. The physical performance of these materials is often limited by fatigue effects, possibly in combination with micro‐cracking phenomena. In this contribution, such micro‐crackbased fatigue effects in ferroelectric materials are computationally investigated by applying a cohesive‐type approach embedded into a finite element context. The geometry or rather discretisation of a representative specimen elaborated in this work refers to a natural grain structure on the meso‐level. Accordingly, the overall response of the underlying grains is approximated by means of coupled continuum elements, while the grain boundaries are discretised with interface elements. Interfacial constitutive relations are chosen to reflect highcycle‐fatigue, which finally is demonstrated by a fatigue‐motivated benchmark‐type boundary value problem. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Constitutive Behaviour of Ferroelectric Piezoceramics: xperiments and Modeling
Authors: Kamlah Marc , Zhou Dayu , Laskewitz Bernd 
Published: December 2008

AbstractPiezoceramics are presently being used increasingly as sensors and actuators in a wide variety of electromechanical applications, for instance, piezoelectric fuel injectors in common rail diesel and gasoline engines. We will introduce the basic mesoscopic domain mechanisms typical of these materials and their relation to macroscopic hysteresis phenomena and piezoelectric properties. In the attempt to improve the performance and especially the reliability of the components, considerable efforts have been made in the development of predictive constitutive models for the coupled and non‐linear electromechanical behaviour of piezoceramics. The success of such constitutive models depends strongly on the availability of suitable measurements. Supported by DFG, fruitful experimental work has been carried out for a commercial soft PZT polycrystalline material (PIC151, PI Ceramic) under co‐axial, coupled electromechanical loading at room temperature. Furthermore, we will discuss a micromechanical finite element simulation of a ferroelectric volume element, where each grain exhibits single crystal behaviour for the switching of its domains. Next, we will turn to macroscopic constitutive modeling. We will present a phenomenological as well as a micromechanically based model. We will present the application of these models to the analysis of poling processes of piezoceramic devices. The main purpose of this publication is to give a summary and to guide the reader to original papers for detailed reports. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Thermomechanically coupled modelling of shape memory alloys in the framework of large strains
Authors: Christ Daniel , Reese Stefanie 
Published: December 2008

AbstractIn the present work we propose a new thermomechanically coupled material model for shape memory alloys (SMA) which includes the two main effects observed for these materials, pseudoelasticity and the shape memory effect. The constitutive equations are derived in the framework of large strains since the martensitic phase transformation involves inelastic deformations up to 10%, or even up to 20% if the plastic deformation after the phase transformation is taken into account. Therefore we apply a multiplicative split of the deformation gradient into elastic and inelastic parts, the latter concerning the martensitic phase transformation. An extended phase transformation function has been considered to include the tension‐compression asymmetry of textured SMA samples. In order to achieve a validation of the model by means of multiaxial experiments as well as to finally apply the concept in the simulation of complex structures, it is implemented into a finite element code. This implementation is based on an innovative integration scheme for the existing evolution equations and a monolithic solution algorithm for the coupled mechanical and thermal fields. The coupling effect is accurately investigated in several numerical examples including pseudoelasticity as well as the free and the suppressed shape memory effect. Finally, the model is used to simulate the pseudoelastic behaviour of an intracranial stent and the shape memory effect in a medical foot staple. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Thermodynamic multifield modeling and simulation of electromagnetic, thermoelastic, viscoplastic solids
Authors: Unger Jaan , Stiemer Marcus , Svendsen Bob , Blum Heribert 
Published: December 2008

AbstractThe purpose of this work is the formulation and application of a continuum thermodynamic approach to the phenomenological modeling of a class of engineering materials which can be formed using strong magnetic fields. This is carried out in the framework of a thermodynamic, internal‐variable‐based formulation in which the deformation, temperature and magnetic fields are in general coupled. This coupling takes the form of the Lorentz force as an additional production of momentum, and the electromotive power as an additional production of energy, in the material. The constitutive formulation is based on the exploitation of the Müller‐Liu entropy principle. The resulting reduced relations are then adapted to the case of electromagnetic forming. In this context, dimensional analysis shows that, over the relevant length‐ and timescales of engineering interest, and for the materials of interest (e.g., aluminum alloys, steels) the evolution of the magnetic field is diffusive in nature, and thermal conduction is negligible. Finally, the model implementation is discussed and applied to the 3D simulation of electromagnetic sheet metal forming. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Effective properties and size effects in filled polymers
Authors: Johlitz Michael , Steeb Holger , Jänicke Ralf , Diebels Stefan 
Published: December 2008

AbstractFilled polymers are of special interest according to their superior mechanical properties. Special attention is given to nano‐filled polymers where not only the volume fraction but also the internal surface has a significant contribution to the effective properties. In the present contribution the increase in stiffness with decreasing size of the fillers at constant volume fraction of the fillers is modelled by a phenomenological, i.e. continuum‐based, approach taking into account large deformations. The proposed multiphase model allows for a systematic investigation of increasing surface‐to‐volume ratio which becomes important for micro‐ and nanosized fillers. The numerical treatment of the proposed model is based on a coupled Galerkin finite element formulation. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Enhanced transthyretin tetramer stability following expression of an amyloid disease transsuppressor variant in mammalian cells
Authors: Kamata Masakazu , Susanto Melisa T. , Chen Irvin S. Y. 
Published: December 2008

AbstractBackgroundThe transthyretin (TTR) amyloidosis is an incurable fatal inherited disease that is characterized by progressive peripheral and autonomic neuropathy. It is caused by missense amyloidogenic mutations in the TTR gene that destabilize the native tetrameric state and lead to the cytotoxic misfolded monomeric state. One interesting variant (T119M) stabilizes heterotetramers with amyloidogenic TTR and, in the reported heterozygous individuals, protects the carriers from disease. In the present study, we characterize in vitro and in vivo the ectopic expression of the human T119M mutant, termed a transsuppressor for TTR amyloid disease.MethodsLentiviral vectors encoding wild or mutant forms of human TTR were constructed and transduced to the human hepatocellular carcinoma cell line, HepG2, or mice. Heterooligomerization between T119M TTR and amyloidogenic variants was analysed by immunoprecipitation following western blotting.ResultsT119M TTR was stably expressed in transduced HepG2 cells and was secreted as an oligomer that can interact with its native partner, retinol‐binding protein. Importantly, the T119M TTR formed secreted heterooligomers with amyloidogenic TTR variants, V30M, L55P and V122I, in HepG2 cells that were more stable than the homooligomers of the same amyloidogenic TTR variants. Human T119M TTR also formed heterooligomers with V30M TTR in transduced mice.ConclusionsThe results obtained in the present study demonstrate the stabilization of heterotetramers by T119M TTR in human cells and suggest that gene transfer of T119M TTR may have potential as a gene therapy for TTR amyloidosis. Copyright © 2008 John Wiley & Sons, Ltd.
Designed recombinant adenovirus type 5 vector induced envelope‐specific CD8+ cytotoxic T lymphocytes and cross‐reactive neutralizing antibodies against human immunodeficiency virus type 1
Authors: Ura Takehiro , Yoshida Atsushi , Xin Ke‐Qin , Yoshizaki Shinji , Yashima Sayaka , Abe Shinya , Mizuguchi Hiroyuki , Okuda Kenji 
Published: December 2008

AbstractBackgroundA monoclonal antibody (mAb) 2F5 binds to the membrane‐proximal external region (MPER) of the transmembrane subunit gp41 of human immunodeficiency virus type 1 (HIV‐1) is known to broadly neutralize HIV‐1 strains. The Adenovirus type 5 vector (Ad5) has been widely applied for HIV‐1 vaccine, and hexon hypervariable region 5 (HVR5) is exposed on viral surface and easily target host immune responses against Ad5.MethodsWe constructed a recombinant adenovirus type 5 vector (rAd5) with a 2F5‐binding epitope (ELDKWA) of MPER on Ad5‐HVR5. In addition, we developed rAd5 encoding the HIV‐1IIIB envelope (Env) gene for the induction of Env‐specific cellular immunity.ResultsThe virus titers of the constructed rAd5 were similar to that of the parental Ad5 vector. Furthermore, high‐dose immunization of rAd5 induced Env‐specific CD8+ cells and high levels of anti‐ELDKWA antibodies. Moreover, an in vitro HIV‐1 neutralization assay indicated that ELDKWA‐specific mAbs derived from rAd5‐immunized mice neutralized a wide range of HIV‐1 strains.ConclusionsThe present study outlines the development of an Ad5‐based HIV‐1 vaccine targeting the hypervariable regions of Ad5. The constructed rAd5 induced an HIV‐1‐specific cellular immune response and neutralizing antibodies against various strains of HIV‐1 simultaneously. Copyright © 2008 John Wiley & Sons, Ltd.
Nitric oxide synthase gene therapy enhances the toxicity of cisplatin in cancer cells
Authors: Adams Catherine , McCarthy Helen O. , Coulter Jonathan A. , Worthington Jenny , Murphy Claire , Robson Tracy , Hirst David G. 
Published: December 2008

AbstractBackgroundNitric oxide (NO·) derived from donor drugs has been shown to be an effective chemosensitizer in vitro. We investigated the combination of inducible nitric oxide synthase (iNOS) gene transfer, driven by a strong constitutive promoter (cytomegalovirus; CMV) with the DNA cross‐linking agent cisplatin in mouse and human tumour cell lines.MethodsProof of principal experiments were performed in the radiation‐induced fibrosarcoma‐1 (RIF‐1) murine cell line. Cells were transfected with constitutively expressed CMV/iNOS plasmid DNA using a cationic lipid vector, before exposure to cisplatin. In vivo efficacy was determined in an intradermal RIF‐1 tumour model, with intraperitoneal administration of cisplatin. Additionally, treatment potential was investigated in various human tumour cell lines including human prostate (DU145 and PC3) and human colon (HT29 and HCT116) cancer cell lines. Experimental endpoints were established using western blot, Greiss test, clonogenic assay and tumour growth delay.ResultsTransfection of RIF‐1 tumour cells in vitro with the CMV/iNOS significantly enhanced the cytotoxicity of cisplatin (0.2–1.0 µM). In vivo transfer of CMV/iNOS by direct injection into established RIF‐1 tumours caused a significant (p = 0.0027) delay in tumour growth. CMV/iNOS gene transfer in vitro resulted in the strong expression of iNOS DNA in all cell lines, and significantly increased levels of NO· in all cell lines except HCT116.ConclusionsSignificant chemosensitization of cisplatin cytotoxicity was observed in the presence of NO· derived from the overexpression iNOS. We conclude that p53 status of the various cell lines was unlikely to be responsible for cisplatin‐induced apoptosis. Copyright © 2008 John Wiley & Sons, Ltd.
Gas‐phase dissociation of ionic liquid aggregates studied by electrospray ionisation mass spectrometry and energy‐variable collision induced dissociation
Authors: Fernandes Ana M. , Coutinho João A. P. , Marrucho Isabel M. 
Published: December 2008

AbstractPositive singly charged ionic liquid aggregates [(Cnmim)m+1(BF4)m]+ (mim = 3‐methylimidazolium; n = 2, 4, 8 and 10) and [(C4mim)m+1(A)m]+ (A = Cl−, BF4−, PF6−, CF3SO3− and (CF3SO2)2N−) were investigated by electrospray ionisation mass spectrometry and energy‐variable collision induced dissociation. The electrospray ionisation mass spectra (ESI‐MS) showed the formation of an aggregate with extra stability for m = 4 for all the ionic liquids with the exception of [C4mim][CF3SO3]. ESI‐MS‐MS and breakdown curves of aggregate ions showed that their dissociation occurred by loss of neutral species ([Cnmim][A])a with a ≥ 1. Variable‐energy collision induced dissociation of each aggregate from m = 1 to m = 8 for all the ionic liquids studied enabled the determination of Ecm, 1/2 values, whose variation with m showed that the monomers were always kinetically much more stable than the larger aggregates, independently of the nature of cation and anion. The centre‐of‐mass energy values correlate well with literature data on ionic volumes and interaction and hydrogen bond energies. Copyright © 2008 John Wiley & Sons, Ltd.