bluuebunny/crossref_metadata_2025_split huggingface dataset:
Modulation of the oncogenic potential of β‐catenin by the subcellular distribution of plakoglobin
Authors: Li Laiji , Chapman Kimberly , Hu Xiuying , Wong Annissa , Pasdar Manijeh 
Published: April 2007

AbstractPlakoglobin (Pg) and β‐catenin are homologous proteins that function in cell–cell adhesion and signaling. The cadherin‐associated form of these proteins mediates adhesion, whereas the cytosolic/nuclear form has a signaling role. Despite their interactions with common cellular partners, β‐catenin has a well‐documented oncogenic potential while Pg has a less characterized tumor suppressor activity. We showed previously that Pg overexpression in Pg‐deficient SCC9 cells (SCC9‐Pg‐WT) induced Bcl‐2 expression and inhibited apoptosis. To assess the exact role of Pg in Bcl‐2 expression, we generated and characterized SCC9 transfectants expressing Pg with a restricted cytoplasmic (Pg‐NES) or nuclear (Pg‐NLS) distribution. We show that Bcl‐2 was expressed regardless of Pg localization, although its level was substantially lower in SCC9‐Pg‐NLS cells. Bcl‐2 expression coincided with increased nuclear β‐catenin levels (Pg‐NES) or a decrease in the level of total and nuclear β‐catenin associated with N‐cadherin and α‐catenin (Pg‐WT and ‐NLS) cells. Bcl‐2 expression also was induced in SCC9 cells overexpressing β‐catenin. In contrast, SCC9 cells expressing mutant Pg proteins, unable to interact with N‐cadherin and α‐catenin, had noticeably lower Bcl‐2 levels. Our data suggest that Bcl‐2 expression is induced by β‐catenin and modulated by Pg. We show that the inhibition of β‐catenin‐dependent TCF transactivation had no effect on Bcl‐2 levels, suggesting that induction of Bcl‐2 expression by β‐catenin and its modulation by Pg may involve factors other than, or in addition, to, TCF. These results provide a possible mechanism for the tumor suppressor activity of Pg via its role as a regulator of the oncogenic potential β‐catenin. © 2007 Wiley‐Liss, Inc.
Persisting hyperekplexia after idiopathic, self‐limiting brainstem encephalopathy
Authors: van de Warrenburg Bart P.C. , Cordivari Carla , Brown Peter , Bhatia Kailash P. 
Published: April 2007

AbstractSymptomatic hyperekplexia is a relatively rare entity, but has been documented in various, mostly brainstem diseases. We report the clinical and neurophysiologic vignette of a patient with a self‐limiting, possibly inflammatory brainstem encephalopathy. Trismus was the presenting feature, but she later developed hyperekplexia. Although most brainstem features resolved spontaneously, the hyperekplexia has persisted. © 2007 Movement Disorder Society
Crystallinity of Linear Low Density Polyethylene and of Blends with High Density Polyethylene
Authors: Edward Graham H. 
Published: April 2007

AbstractBlends of linear low density and high density polyethylene are examined by x‐ray diffraction and differential scanning calorimetry in order to characterise the crystalline morphology and to investigate the compatibility of the polymers. The polymers are found to form a co‐crystalline phase under a variety of conditions, and can thus be regarded as compatible. The lamellar distributions obtained from the differential scanning calorimetry melting thermograms are found to be dominated by the presence of the high density polyethylene, and this is attributed to the higher mobility of the high density molecules. The lattice parameters of the crystalline phases are found to increase with increasing side branch content.
Ultrasonic Study of Molecular Association of Polyethylenoxide Aqueous Solutions (A Method to Determine Molecular Weight)
Authors: Hassun Subhi Kemal , Al‐Madfai Suham H. F. , Al‐Jarrah Mustafa M. F. 
Published: April 2007

AbstractUltrasonic velocity and isoentropic compressibility measurements are reported on aqueous solutions of polyethylenoxide of different molecular weights and different concentrations using pulsed ultrasonic apparatus operating at 2 MHz and 310 K. The data obtained as a function of concentration indicate the magnitude of the contribution due to relaxation of the backbone of the ethylene group. The results show a linear increase of density, velocity and viscosity values with increasing molecular weight and concentration of PEO. In contrast, the isoentropic compressibility decreases with increasing of molecular weight and concentration of PEO. A mathematical equation correlating isoentropic compressibility and molecular weight of the polymer is suggested. This was applied to the calculation of the molecular weight of unknown samples of PEO from their measured isoentropic compressibility; the results obtained agreed well with those obtained from osmometry.
Thermal Degradation of Polystyrene
Authors: Guaita Marino 
Published: April 2007

AbstractThe thermal degradation of polystyrene in the absence of oxygen is examined, at temperatures above or below 300°C. The decrease in degree of polymerisation occurring either with negligible volatilisation at lower temperatures, or with evolution of low molecular weight products at higher temperatures, is simulated by Monte‐Carlo procedures. The results suggest that below 300°C, scission of the polymer chains is random, and involves also a minor fraction of some abnormal, as yet unidentified, structures. Above 300°C, an extensive intermolecular transfer process seems to be the main cause of the decrease in degree of polymerisation, whereas an overall depolymerisation of 100 structural units at each chain scission is the source of volatilisation.
Some Effects of Structure, Composition and Cure on the Water Absorption and Glass Transition Temperature of Amine‐cured Epoxies
Authors: Johncock Peter , Tudgey Graham F. 
Published: April 2007

AbstractThe effect of structure, composition, and cure on the water absorption and Tg of amine‐cured epoxies was investigated. Water absorption is considered to depend on the polar group concentration and type, and on the amount of free volume in the polymer network. The contribution of polar groups in terms of their hydrogen bonding capabilities is reflected by the effect of meta (with respect to the diglycidylamino group) chloro, bromo, and methyl substituents on the water absorption of bis[N,N‐bis(2,3‐epoxypropyl)‐4‐aminophenyl]methane cured with 4,4′‐diaminodiphenylsulphone. The observed water absorptions are in line with the expected electronic effects of the substituents on the basicity of the amine group. Substituents in the ortho position adversely affect the hydrogen bonding capability of the amine group and limit the extent of reaction by steric interference. Examination of four O‐glycidyl systems (Epon 825, Epon 1153/114, Epon 1031, and Dow XD‐7342) cured with 4,4′‐diaminodiphenylsulphone has revealed quite a good linear relationship between the equilibrium water absorption and Tg for a particular hardener concentration irrespective of the epoxy compound employed. Networks ranged from those of low Tg (110°C) and water absorption (1.3%) to those of high values (300°C and 6.1%) for these parameters. Differences in slope for low (50‐65%) and high (100%) stoichiometric amounts of hardener are attributed to differences in the relative importance of OH/epoxy and NH2 or NH/epoxy reactions. The theoretical polar group concentrations and polar group type are much the same for these different systems and thus, free volume is considered to be a function of Tg and to play an important part in determining the level of water absorption.
Network Polymers Based on Epoxy Oligomers and Dicyandiamide
Authors: Markevitch Mikhail A. , Irzhak Vadim I. 
Published: April 2007

AbstractThe formation of network polymers by curing epoxy oligomers with dicyandiamide was investigated. The oligomers had the structureIt was shown that the reaction between hydroxyl and epoxy groups is important in this process. The strength‐deformation properties of the network polymers obtained were studied. Calculations of elastic active network chains were carried out by the method of branching processes. Good agreement was obtained between calculated and experimental data.
13C Nuclear Magnetic Resonance Studies of Phenol‐Formaldehyde Resins and Related Model Compounds 2 ‐ Analysis of Sequence Structure in Resins
Authors: Pethrick Richard A. , Thomson Barry 
Published: April 2007

AbstractThe paper reports 13C nuclear magnetic resonance spectra of novolac resins and the variation of the composition of the reaction mixture during the in situ preparation of resin. It is observed that in the initial stages of the reaction ortho substitution occurs; however the hemiacetal rather than the methylol derivative is observed. These methylol substituted intermediates are highly unstable and a better appreciation of the relative rates of structure formation can be obtained from an analysis of the methylene bridge region, para‐para Bridges are the first to appear, the next are the ortho‐para and finally the ortho‐ortho linkages are observed. Analysis of the relative intensities of ortho and para bridge carbon atoms allows identification of the isomeric composition of the final resin. The proportion of each isomer depends on the catalyst used in synthesis of the resin.
Application of thermal methods in the characterisation of poly(urethane‐urea)s formed by reaction injection moulding
Authors: Ryan Anthony J. , Stanford John L. , Still Richard H. 
Published: April 2007

AbstractDifferential scanning calorimetry (DSC) and dynamic mechanical thermal analysis (DMTA) have been used in conjunction with tensile testing and transmission electron microscopy (TEM) to characterise novel segmented poly(urethane‐urea) (PUU) network materials formed by reaction injection moulding (RIM).Materials were based on a modified liquid 4,4′‐diphenylmethane diisocyanate and a polyether triol in admixture with one of three hindered aromatic diamines: 3,5‐diethyltoluene diamine (DETDA); methylene‐bis‐2,6‐diisopropylaniline (MMIPA); methylene‐bis‐(2‐methyl‐6‐isopropylaniline) (MMIPA).The materials ranged from tough translucent elastomers to opaque brittle plastics depending on the chemical nature and weight fraction of the hard segments (HS). DSC and DMTA studies showed the PUU materials to be phase‐separated; this was confirmed by TEM and tensile testing. The soft‐segment glass transition temperatures (DSC and DMTA) were independent of composition but varied with diamine structure. Hard‐segment glass transition temperatures could only be evaluated by DMTA and no evidence of crystallinity was found by thermal methods or by wide angle x‐ray diffraction. Heat capacity measurements and DMTA suggested that some degree of phase mixing had occurred, to a greater extent in the DETDA and MDIPA systems.Phase inversion was observed by DMTA and confirmed at ∼55% hard‐segment content for DETDA systems by tensile testing.
Generational consciousness and retirement communities
Authors: McHugh Kevin E. 
Published: April 2007

AbstractTime and collective historical experience loom large in the formation of generations. I argue that spatial proximity cements generational consciousness among seniors in Arizona retirement communities who identify themselves as members of the Second World War generation. The argument twins Karl Mannheim's social‐historical conception of generations and Hannah Arendt's political philosophy which underscores the space of appearance in the public realm in identity formation. It is through congregating, interacting and conversing on a daily basis that seniors in retirement enclaves affirm and reaffirm who they are, both to themselves and outsiders. I draw upon a suite of Arizona case studies, 1988–2000, in revealing ‘voices’ for a slice of the Second World War generation. Discussions revolving around family, community and national life reveal beliefs and values coalescing around four themes: (1) splendid isolation; (2) dissolution of values; (3) absence of children; and (4) fraying the social compact. The space of appearance within retirement enclaves engenders a strong sense of collective identity and belonging in ageing and, simultaneously, leads to questions about implications and consequences of intergenerational separation. I conclude with a poignant multigenerational experience as suggestive of the potency of intergenerational contact and exchange. Copyright © 2007 John Wiley & Sons, Ltd.
Low temperature growth of ZnO thin film by metalorganic chemical vapor deposition
Authors: Kim Dong Chan , Kong Bo Hyun , Cho Hyung Koun , Lee Jeong Yong , Park Dong Jun 
Published: April 2007

AbstractPolycrystalline ZnO thin films with a preferred orientation were successfully grown by metal organic chemical vapor deposition at temperatures ≤300 °C. By injecting additional Ar gas through a by‐pass line, good quality ZnO films were grown at low temperature. The ZnO films grown at substrate temperatures <200 °C showed a porous microstructure whereas a dense undoped ZnO film showing a high conductivity and no Zn phases was grown at 210 °C. The ZnO film grown at low temperatures by MOCVD showed improved emission properties compared with the films grown by sputtering. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Optical characterization of Zn0.97Mn0.03Se/ZnSe0.92Te0.08 type II multiple‐quantum‐well structures
Authors: Lin D. Y. , Shiu J. J. , Wu J. D. , Yang C. S. , Chou W. C. 
Published: April 2007

AbstractThe optical characterization of type II Zn0.97Mn0.03Se/ZnSe0.92Te0.08 multiple‐quantum‐well structures have been studied using photoluminescence (PL), temperature‐dependent PL, polarized PL, power‐dependent PL, and photoreflectance (PR) in this study. The PL data reveal that the band alignment of the ZnMnSe/ZnSeTe system is type II. Comparing with the theoretical calculation based on the Schrodinger equation, the valence band offset is estimated to be 0.6 eV. From the power‐dependent PL spectra, it is observed that the peak position of PL spectra shows a blueshift under different excitation power. The blueshift can be interpreted in terms of the band‐bending effect due to spatially photoexcited carriers in a type II alignment. The thermal activation energy (EA) for quenching the PL intensity was determined from tem‐ perature‐dependent PL spectra. The thermal activation energy was found to decrease as the thickness of ZnMnSe and ZnSeTe layers decreased. The polarized PL spectra exhibit a large in‐plane polarization with the polarization degree up to 50%. The polarization does not depend on the excitation intensity as well as temperature. The large polarization is an inherent orientation of the interface chemical bonds. The higher transition features observed in PR spectra show a blueshift with the similar trend observed in the PL spectra as decreasing the thickness of ZnSeTe layer. This result provides a consistent evidence for the assumption that square‐like well shapes were built in the ZnSeTe layers. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Optical and photoelectrical properties of CdSxSe1–xfilms produced by screen‐printing technology
Authors: Tivanov M. , Ostretsov E. , Drozdov N. , Survilo L. , Fedotov A. , Trofimov Yu. , Mazanik A. 
Published: April 2007

AbstractIn this paper the optical and photoelectrical properties of CdSxSe1–xfilms prepared using the screen‐printing and sintering technique, were studied. CdCl2was used both as a sintering flux and as a doping agent. CuCl was also used as a doping agent. The temperatures and times of preparation varied in the range of 500–600 °C and 5–60 min, respectively. The as‐prepared films were characterized by the scanning electron microscopy, micro‐probe X‐Ray analysis, photoluminescence and photoconductance methods. Our investigations have shown that photoresponse of the CdSxSe1–xfilms prepared by a screen‐printing method can be suitable for the production of large‐area photosensitive devices. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Large‐Scale, Hot‐Filament‐Assisted Synthesis of Tungsten Oxide and Related Transition Metal Oxide Nanowires
Authors: Thangala Jyothish , Vaddiraju Sreeram , Bogale Rahel , Thurman Ryan , Powers Trevor , Deb Biswapriya , Sunkara Mahendra K. 
Published: April 2007

AbstractA scalable and versatile method for the large‐scale synthesis of tungsten trioxide nanowires and their arrays on a variety of substrates, including amorphous quartz and fluorinated tin oxide, is reported. The synthesis involves the chemical‐vapor transport of metal oxide vapor‐phase species using air or oxygen flow over hot filaments onto substrates kept at a distance. The results show that the density of the nanowires can be varied from 106–1010 cm−2 by varying the substrate temperature. The diameter of the nanowires ranges from 100–20 nm. The results also show that variations in oxygen flow and substrate temperature affect the nanowire morphology from straight to bundled to branched nanowires. A thermodynamic model is proposed to show that the condensation of WO2 species primarily accounts for the nucleation and subsequent growth of the nanowires, which supports the hypothesis that the nucleation of nanowires occurs through condensation of suboxide WO2 vapor‐phase species. This is in contrast to the expected WO3 vapor‐phase species condensation into WO3 solid phase for nanoparticle formation. The as‐synthesized nanowires are shown to form stable dispersions compared to nanoparticles in various organic and inorganic solvents.
Structural vibrations and noise reduction by piezoelectric active control
Authors: Ghiringhelli G. L. 
Published: April 2007

AbstractThe present work describes a numerical procedure for the design of a piezoelectric active control system capable of reducing the acoustic emission from forced structural elements. The characterisation of the actively controlled structure is carried out through an integrated electro‐elastic Finite Element (FE) approach. Because of the possibility of using piezoelectric layers as self‐sensing actuators, a simple and effective collocated control technique is employed; within this framework different control laws are allowed by the use of external electric circuits implementing appropriate measurement conditioning. The acoustic pressure field around the vibrating structure is simulated by using a boundary elements method interfaced to the FE structural model through mobility matrices.
Fault tolerant structural control systems for civil engineering applications
Authors: Battaini M. , Dyke S. J. 
Published: April 2007

AbstractThe objective of this work is to experimentally examine some practical issues relating to the reliability and performance of active structural control systems. Using the newly constructed shaking table in the Department of Structural Mechanics at the University of Pavia, experiments were conducted employing an actively controlled, three story test structure. A DC‐motor based active mass driver system was used as the active control device. An H2/LQG controller based on acceleration feedback is applied to the system. The first objective of this work is to demonstrate the efficacy of the acceleration feedback control strategy. Next, two experiments are conducted with the goal of investigating fault tolerant control system design. In the first case, the occurence of a sensor failure is simulated experimentally, and the resulting controlled performance and robustness characteristics are assessed. The second set of tests is to evaluate the ability of the controller to reduce the structural responses when reduced information is available for control action determination. Both of these issues are important practical concerns in the design and implementation of a structural control system.
Experimental study of active control using neural networks
Authors: Chen H. M. , Qi G. Z. , Yang J. C. S. , Amini F. 
Published: April 2007

AbstractSignificant progress has been achieved in the active control of civil engineering structures in recent years. Although many control algorithms has been proposed, only few experiments in active structural control have been performed. In this paper, active structural control experiments were carried out using a scaled model structure simulating a three‐story steel frame building. The model was subjected to a base motion on a shake table. A neural network based controller was implemented to control the response of the structure. This trained neural controller was implemented to control the response of the structure. It is experimentally verified that the neural network is able to generalized to new inputs, i.e. a properly trained neural network is capable of providing sensible outputs when presented with input data that has never been used during training. Results from this experimental study indicate great promise for the control of civil engineering structures under dynamic loadings using the artificial neural network controller.
Nonlinear decentralized active tendon control of cable‐stayed bridges
Authors: Magaña M. E. , Rodellar J. 
Published: April 2007

AbstractA nonlinear decentralized active tendon controller that substantially reduces the magnitude of the vibrations of a segment of a cable‐stayed bridge induced by a seismic excitation is presented in this paper. The model used to represent the dynamic behaviour of the bridge takes into account the inherent nonlinearities due to the stay cables geometry. This is in contrast with traditional models used by previous designers of active controllers of cable‐stayed bridges, who assumed completely linear models. The proposed controller is comprised of a linear and a nonlinear part. Its performance is verified via digital computer simulation.
Input‐signal characterization for shaking‐tables
Authors: Casciati F. , Faravelli L. , Petrini L. 
Published: April 2007

AbstractA large worldwide earthquake data‐bank is available for numerical and experimental response analyses of base‐excited structural systems. Most of these accelerograms are stored in their uncorrected form and this is appropriate and convenient since they must be differently processed for different engineering applications. Record processing is a necessary step toward the use of recorded data in numerical simulations: it deletes spurious low and high frequency content, introduced in detection, acquisition, storage and digitalization of the signal. Moving from numerical to experimental analyses, the testing machine acts as a filter and, hence, the processing could be no longer required. The paper tries to investigate this aspect.
Controlled structural systems: Design and reliability
Authors: Battaini M. 
Published: April 2007

AbstractThis paper is an extended summary of the dissertation presented by the author for the Ph.D degree in civil engineering at the University of Pavia.The aim of the dissertation is the design and the experimental validation of an active control scheme, the simulation of possible real operating problems (such as sensor failures) and the reliability assessment of the active control system. The goal is to identify and discuss a scenario of possible problems the designer will meet in implementing an active control scheme.The work consists of a preliminary theoretical part, necessary for the implementation of the active control system, an experimental activity on a suitably scaled structural model and a reliability analysis of the adopted active control system.