bluuebunny/crossref_metadata_2025_split huggingface dataset:
First‐principles calculations of the stability and electronic properties of the PbTiO3 (110) polar surface
Authors: Zhang Guo‐Xu , Xie Ying , Yu Hai‐Tao , Fu Hong‐Gang 
Published: December 2008

AbstractThe structural and electronic properties of five terminations of cubic lead titanate (PbTiO3) (110) polar surface were investigated by first‐principles total‐energy calculations using a periodic slab model. On the PbTiO termination, an anomalous filling of conduction band was observed, whereas on the O2 termination, two surface oxygen atoms formed a peroxo group, demonstrating that the electronic structures of the two stoichiometric terminations undergo significant changes with respect to bulk materials. However, for the three nonstoichiometric TiO‐, Pb‐, and O‐terminated surfaces, their electronic structures are very similar to bulk. Charge redistribution results for the five terminations confirmed that electronic structure and surface composition changes are responsible for their polarity compensation. However, which mechanism actually dominates the stabilization process depends upon energetic considerations. A thermodynamic stability diagram suggested that the two stoichiometric terminations are unstable; however, the three nonstoichiometric terminations can be stabilized in some given regions. Furthermore, this study indicates that the very different stabilities and surface states filling behaviors of the PbTiO3 (110) polar surface with respect to SrTiO3 and BaTiO3 ones seem to originate from the partially covalent characteristics of PbO pairs. © 2008 Wiley Periodicals, Inc. J Comput Chem 2009
Numerical examination of the extended phase‐space volume‐preserving integrator by the Nosé‐Hoover molecular dynamics equations
Authors: Queyroy Séverine , Nakamura Haruki , Fukuda Ikuo 
Published: December 2008

AbstractThis article illustrates practical applications to molecular dynamics simulations of the recently developed numerical integrators [Phys Rev E 2006, 73, 026703] for ordinary differential equations. This method consists of extending any set of ordinary differential equations in order to define a time invariant function, and then use the techniques of divergence‐free solvable decomposition and symmetric composition to obtain volume‐preserving integrators in the extended phase space. Here, we have developed the technique by constructing multiple extended‐variable formalism in order to enhance the handling in actual simulation, and by constituting higher order integrators to obtain further accuracies. Using these integrators, we perform constant temperature molecular dynamics simulations of liquid water, liquid argon and peptide in liquid water droplet. The temperature control is obtained through an extended version of the Nosé‐Hoover equations. Analyzing the effects of the simulation conditions including time step length, initial values, boundary conditions, and equation parameters, we investigate local accuracy, global accuracy, computational cost, and sensitivity along with the sampling validity. According to the results of these simulations, we show that the volume‐preserving integrators developed by the current method are more effective than traditional integrators that lack the volume‐preserving property. © 2008 Wiley Periodicals, Inc. J Comput Chem, 2009
Multiple Markov transition matrix method: Obtaining the stationary probability distribution from multiple simulations
Authors: Sakuraba Shun , Kitao Akio 
Published: December 2008

AbstractWe herein propose the multiple Markov transition matrix method (MMMM), an algorithm by which to estimate the stationary probability distribution from independent multiple molecular dynamics simulations with different Hamiltonians. Applications to the potential of mean force calculation in combination with the umbrella sampling method are presented. First, the performance of the MMMM is examined in the case of butane. Compared with the weighted histogram analysis method (WHAM), the MMMM has an advantage with respect to the reasonable evaluation of the stationary probability distribution even from nonequilibrium trajectories. This method is then applied to Met‐enkephalin nonequilibrium simulation. © 2008 Wiley Periodicals, Inc. J Comput Chem, 2009
Overexpression of ΔNp63 in a human nasopharyngeal carcinoma cell line downregulates CKIs and enhances cell proliferation
Authors: Chiang Chi‐Tai , Chu Wing‐Keung , Chow Shu‐Er , Chen Jan‐Kan 
Published: December 2008

Abstractp63 belongs to a member of the tumor suppressor protein p53 family. Due to alternative promoter usage, two types of p63 proteins are produced. The ΔNp63 isoform lacks the N‐terminal transactivation domain and is thought to antagonize TAp63 and p53 in target gene regulation. ΔNp63 has been found to be overexpressed in numerous human squamous cell carcinomas, including nasopharyngeal carcinoma (NPC). However, the role of ΔNp63 overexpression in NPC pathogenesis has not been clear. In this study, we use a ΔNp63 overexpressing human NPC cell line (NPC‐076) to explore the possible roles of ΔNp63 in cell proliferation and cell‐cycle regulation. We found that the proliferation of NPC‐076 cell is greatly suppressed when the overexpressed ΔNp63 is silenced by specific ΔNp63 siRNA. Further studies show that ΔNp63 silencing results in the upregulation of CKIs, including p27kip1 and p57kip2 in both mRNA and protein levels. Cell‐cycle analysis shows that ΔNp63 silencing also results in an increased G1 phase cell and apoptotic cell population. Our findings indicate that ΔNp63 plays important roles in the regulation of NPC‐076 cell‐cycle progression, and may play a role in the maintenance of NPC‐076 tumor cell phenotype. J. Cell. Physiol. 219: 117–122, 2009. © 2008 Wiley‐Liss, Inc.
A novel role of ERK5 in integrin‐mediated cell adhesion and motility in cancer cells via Fak signaling
Authors: Sawhney Rajinder S. , Liu Wensheng , Brattain Michael G. 
Published: December 2008

AbstractIn metastatic cancer, high expression levels of vitronectin (VN) receptors (integrins), FAK, and ERK5 are reported. We hypothesized that integrin‐mediated ERK5 activation via FAK may play a pivotal role in cell adhesion, motility, and metastasis. ERK5 and FAK phosphorylation when metastatic MDA‐MB‐231 and PC‐3 cells were plated on VN was enhanced. Further experiments showed co‐immunoprecipitation of integrins β1, αVβ3, or αVβ5 with ERK5 and FAK. To gain better insight into the mechanism of ERK5, FAK, and VN receptors in cell adhesion and motility, we performed loss‐of‐function experiments using integrin blocking antibodies, and specific mutants of FAK and ERK5. Ectopic expression of dominant negative ERK5/AEF decreased ERK5 and FAK (Y397) phosphorylation, cell adhesion, and haptotactic motility (micromotion) on VN. Additionally, DN FAK expression attenuated ERK5 phosphorylation, cell adhesion, and motility. This study documents the novel finding that in breast and prostate cancer cells, ERK5 is a critical target of FAK in cell adhesion signaling. Using different cancer cells, our experiments unveil a novel mechanism by which VN receptors and FAK could promote cancer metastasis via ERK5 activation. J. Cell. Physiol. 219: 152–161, 2009. © 2008 Wiley‐Liss, Inc.
Molecular genetics of ameloblast cell lineage
Authors: Bei Marianna 
Published: December 2008

AbstractLate tooth morphogenesis is characterized by a series of events that determine crown morphogenesis and the histodifferentiation of epithelial cells into enamel‐secreting ameloblasts and of mesenchymal cells into dentin‐secreting odontoblasts. Functional ameloblasts are tall, columnar, polarized cells that synthesize and secrete a number of enamel‐specific proteins. After depositing the full thickness of enamel matrix, ameloblasts shrink in size and regulate enamel maturation. Amelogenesis imperfecta (AI) is a heterogeneous group of inherited defects in enamel formation. Clinically, AI presents as a spectrum of enamel malformations that are categorized as hypoplastic, hypocalcified, or hypomaturation types, based upon the thickness and hardness of the enamel. The different types of AI are inherited, either as X‐linked, autosomal‐dominant, or autosomal‐recessive traits. Recently, several gene mutations have been identified to cause the subtypes of AI. How these genes, however, coordinate their function to control amelogenesis is not understood. In this review, we discuss the role of genes that play definitive role on the determination of ameloblast cell fate and life cycle based on studies in transgenic animals. J. Exp. Zool. (Mol. Dev. Evol.) 312B:437–444, 2009. © 2008 Wiley‐Liss, Inc.
Positional dependence of FDTD mode detection in photonic crystal systems
Authors: Stark G. A. , Mishrikey M. , Robin F. , Jaeckel H. , Hafner C. , Vahldieck R. , Erni D. 
Published: December 2008

AbstractWe have developed an algorithm for evaluating the accuracy and reliability of photonic crystal (PhC) simulations, and used it to analyze the influence of excitation and detector placement in finite‐difference time‐domain algorithm (FDTD) simulations of two canonical PhC systems. In order to perform this computationally expensive analysis, we evaluated the use of filter diagonalization as an alternative to the Fourier Transform for mode detection, and developed a parallelization algorithm to take advantage of the inherent concurrency in simulating periodic systems. A map of locations where mode detection fails was generated, and we show that this is equivalent to a map of the node densities of the system. In addition to the expected high nodal densities at the symmetry areas of each system, we find more difficult to characterize patterns of high nodal density for the higher‐order modes. Based on the observed behavior we are able to provide concrete rules to optimize the detection and excitation of modes in FDTD simulations of PhC systems. Although PhCs were studied, the presented strategies and results apply to the much broader class of all computational time‐domain problems where Bloch–Floquet boundary conditions are used. Copyright © 2008 John Wiley & Sons, Ltd.
Halide‐ion‐assisted increase of surface‐enhanced hyper‐Raman scattering: a clear observation of the chemical effect
Authors: Palonpon Almar , Ichimura Taro , Verma Prabhat , Inouye Yasushi , Kawata Satoshi 
Published: December 2008

AbstractWe show that the increase of surface‐enhanced hyper‐Raman scattering (SEHRS) intensity of organic dye molecules adsorbed on single silver (Ag) colloid aggregate in the presence of halide ions is a direct evidence of the chemical effect in the enhancement mechanism. Time‐dependent SEHRS measurements before and after adding halide ions enabled us to distinctly observe the chemical effect. The presence of the halide ions results to a more stable chemical interaction between metal and dye molecule, making it more resistant against photodegradation effects. This study can contribute in elucidating the chemical effect mechanism and aid in the development of SEHRS as a useful spectroscopic tool. Copyright © 2008 John Wiley & Sons, Ltd.
Evaluating the guest experience at theme parks: an empirical investigation of key attributes
Authors: Milman Ady 
Published: December 2008

AbstractThe study identified and documented a consumer‐oriented attribute inventory for evaluating theme parks. Data were collected from 608 Central Florida residents, domestic and international tourists who identified and ranked the level of importance of 41 attributes and park characteristics when visiting a typical theme park. Further analysis of the data using factor analysis identified seven key constructs that summarised important areas of concern when consumers evaluate theme parks. The majority of these factors were related to guest experiences such as (i) entertainment variety and quality; (ii) courtesy, cleanliness, safety and security; (iii) food variety and value for money; (iv) quality of theming and design; (v) availability and variety of family‐oriented activities; (vi) quality and variety of rides and attractions; and (vii) pricing and value for money. Implications for theme park owners, operators and marketing executives were discussed in light of the increasing demand for distinctive guest experiences while visiting theme parks. Copyright © 2008 John Wiley & Sons, Ltd.
Structure and Properties of Mono‐, Di‐, Tri‐ and Multiblock Segmented Copolymers with Diamide Hard Segments
Authors: Arun Araichimani , Dullaert Konraad , Gaymans Reinoud J. 
Published: December 2008

AbstractWell‐defined segmented block copolymers were studied as the number and position of hard segments in the chain was varied. The hard segments were diamides of uniform length (A), and the synthesized copolymers were mono‐, di‐, tri‐ or multiblock using the soft segment (B), poly(tetramethylene oxide), with a molecular weight of 2 900 g mol−1 and extended with terephthalate groups to reach a maximum of 20 000 g mol−1. The diamide segments in the chain displayed very high crystallinities and a ribbon‐like structure with high aspect ratio. The copolymer without hard segments was a semi‐solid. For the materials with one diamide unit in the chain, the modulus was high but the yield and fracture strengths low. When two or more diamide units were used, both the modulus and values for the yield and fracture strengths were high.magnified image
Fluorescence Investigations of Oxygen‐Doped Simple Amine Compared with Fluorescent PAMAM Dendrimer
Authors: Chu Chih‐Chien , Imae Toyoko 
Published: December 2008

AbstractBlue emission of oxygen‐doped tertiary amine (triethylamine), a key unit of fluorescent poly(amido amine) dendrimer, was demonstrated. It was found that the fluorescence intensity could be further enhanced if the tertiary amines locate densely in the dendrimer interior as the branching sites. Moreover, a solvatochromic phenol blue, instead of oxygen, is able to induce the blue fluorescence of the tertiary amino‐branching sites based on a guaranteed host‐guest complexation of phenol blue molecules and dendrimer interior.magnified image
Co‐Continuous Polymeric Nanostructures via Simple Melt Mixing of PS/PMMA
Authors: Pu Gongwei , Luo Yingwu , Lou Qianchuan , Li Bogeng 
Published: December 2008

AbstractBlends of polystyrene/poly(methyl methacrylate) (PS/PMMA) (30/70) prepared by simple melt mixing form a droplet (PS) in‐matrix (PMMA) morphology. It is found that addition of a carefully designed copolymer PS‐b‐P(S‐ran‐MMA) (SSM) compatibilizer could convert the morphology into a co‐continuous system. Indeed, the continuity of the dispersed PS phase increased with an increase in PS‐b‐P(S‐ran‐MMA) content, and a fully co‐continuous morphology (continuity = 100%) was obtained at 20% SSM fraction with a characteristic size of 100 nm.magnified image
Cross‐Linking and Degradation Properties of Plasma Enhanced Chemical Vapor Deposited Poly(2‐hydroxyethyl methacrylate)
Authors: Pfluger Courtney A. , Carrier Rebecca L. , Sun Bing , Ziemer Katherine S. , Burkey Daniel D. 
Published: December 2008

AbstractPlasma Enhanced Chemical Vapor Deposition (PECVD) of poly‐2‐hydroxyethyl methacrylate (pHEMA) biocompatible, biodegradable polymer films were produced alone and cross‐linked with ethylene glycol diacrylate (EGDA). Degree of cross‐linking was controlled via manipulation of the EGDA flow rate, which influenced the amount of swelling and the extent of degradation of the films in an aqueous solution over time. Noncross‐linked pHEMA films swelled 10% more than cross‐linked films after 24 h of incubation in an aqueous environment. Increasing degree of film cross‐linking decreased degradation over time. Thus, PECVD pHEMA films with variable cross‐linking properties enable tuning of gel formation and degradation properties, making these films useful in a variety of biologically significant applications.magnified image
FEM analysis of localized deformation behaviour in pseudoelastic NiTi shape memory alloys
Authors: Wang X.M. , Lu Z.Z. , Yue Z.F. , Deng C.H. 
Published: December 2008

AbstractThis paper takes into account the localized deformation behaviour of a pseudoelastic NiTi shape memory alloy with finite element method. A three‐dimensional micromechanical model has been developed, in which the difference between the elastic properties of austenite and martensite is considered. The model is implemented as User MATerial subroutine (UMAT) into ABAQUS. Then, a polycrystalline NiTi shape memory alloy with [1 1 1] texture under tensile loading is simulated. The main features of the propagation of the deformation band reported in literatures are captured in the simulation. It is also shown that the initiation and propagation of the deformation bands are strongly affected by the geometry of the specimens.
Entwicklung des Reibnietens als neues Fügeverfahren für Kunststoff und Leichtbaulegierungen
Authors: Amancio‐Filho S. T. , dos Santos J. F. 
Published: December 2008

AbstractDie steigenden Forderungen nach Umweltverträglichkeit, Kosteneinsparung, und hochleistungsfähigen Endprodukten hat Wissenschaftler und Ingenieure veranlasst neue Materialien und Technologien zu entwickeln. Daraus resultierten beispielsweise die Polymer‐Metall Hybridstrukturen. Diese werden insbesondere in Transport‐ und moderner Bauindustrie angewandt. Geeignete herkömmliche Fügeverfahren dafür (Kleben und mechanische Fügeverfahren) sind üblicherweise entweder teuer, weisen limitierte Festigkeit und Anwendbarkeit auf oder sind nicht umweltfreundlich. Die im Rahmen dieser Arbeit behandelte neue Reibnieten („FricRiveting”︁) Methode für Polymer‐Metall Mischverbindungen wurde hierfür als alternative, zuverlässige, umweltfreundliche, und potenziell kostengünstige Punktverbindungstechnik entwickelt, beschrieben und nachgewiesen. In der einfachsten Variante des Reibnietens dringt eine in Rotation versetzte zylinderförmige metallische Niete in die Oberfläche eines oder mehrerer Kunststoff‐Grundwerkstoffe ein. Aufgrund der hohen Rotation bzw. des hohen Axialdruckes wird Reibungswärme erzeugt. Mit Erreichen einer vorprogrammierten Zeit erhöht sich die Prozesstemperatur signifikant. Dadurch wird die Spitze der Niete plastifiziert; in diesem Moment wird die Rotation verzögert und der Axialdruck in die Fügepartner erhöht. Als Folge verformt sich die Nietenpitze entsprechend des Druckverhältnisses. Nach der Abkühlungsphase wird die verformte Nietspitze formschlüssig im Kunststoff verankert. Die in dieser Arbeit vorgeschlagenen Theorien, und Mechanismen wurden bei Verbindungen von Polyetherimid (PEI) und Aluminium 2024‐T351 (Al‐Cu‐Mg Legierung) nachgewiesen. Punkt‐ und Überlappverbindungen mit hohem Festigkeits‐Wirkungsgrad unter Raumtemperatur (der Zugfestigkeit‐ Wirkungsgrad betrug bis zu ca. 97 % der Nietfestigkeit und der Scherzugfestigkeit‐Wirkungsgrad betrug bis zu ca. 70 % der Kunststofffestigkeit) wurden reibgenietet. Zum Schluss wurden die Gefügeänderung und mikrostrukturellen Eigenschaften dieser reibgenieteten Verbindungen beschrieben. Die im Laufe dieser Arbeit entstandenen wissenschaftlichen bzw. technischen Ergebnisse beweisen die Durchführbarkeit des Reibnietens. Als Ergebnis dieser Arbeit kann das Reibnieten als potenzielle zuverlässige, einfache, kostengünstige, und umweltfreundliche Fügetechnik für Polymer‐Metall Verbindungen vorgeschlagen werden.
Carbonated hydroxyapatite nanopowders for preparation of bioresorbable materials
Authors: Kovaleva E. S. , Shabanov M. P. , Putlayev V. I. , Filippov Ya. Yu. , Tretyakov Y. D. , Ivanov V. K. 
Published: December 2008

AbstractIncorporation of carbonate ions to the crystal structure of carbonated hydroxyapatite (CHAp) leads to the formation of point defects (vacancies) in Ca‐ and OH‐sublattices as well as to microstrains revealed in CHAp nanocrystals. Various techniques, such as XRD, FTIR, TEM, FESEM/EDX, TG/DTA, AES (ICP), wet chemical analysis, Ca‐ionometry, microvolumetric analysis of evolved CO2, BET adsorption, were applied to determine an efficiency of carbonate substitution, and to quantify the elemental composition, as well as to characterize the structure of the carbonated hydroxyapatite and the site(s) of carbonate substitution. It was shown that there is insignificant incorporation of Na into the crystal structure of HAp. Over the range of 0–4 % wt. (x<0.25), the substitution of OH‐ by CO32‐ takes place leading to A‐Type of CHAp, further increase of CO32‐‐content enhances PO43‐‐substitution giving AB‐type of CHAp. According to in vitro test, the bioactivity of the samples is increasing with the growth of carbonate content due to accumulation of the defects in CHAp nanocrystals.
On the impact of managerial bonus systems on firm profit and market competition: the cases of pure profit, sales, market share and relative profits compared
Authors: Jansen Thijs , van Lier Arie , van Witteloostuijn Arjen 
Published: December 2008

AbstractBy designing remuneration schemes based on a bonus rewarding specific firm‐level outcomes, the owners/shareholders of a firm can manipulate the behavior of their managers. In practice, different bonus anchors take center stage: some are profit‐based, others use sales as the key yardstick and still different ones focus on relative performance vis‐à‐vis a peer group. In this paper, we focus on the impact of remuneration schemes on firm‐level profitability. The profit effect is investigated for (all possible combinations of) four bonus systems using delegation games. In the context of a linear Cournot model for two or three firms, we model a two‐ or three‐stage decision structure where, in the first stage (or first two stages), an owner decides on the bonus system for his manager and where, in the final stage, the manager takes the daily output decision for her firm. It appears that the bonus system based on relative (profits) performance is superior throughout. Copyright © 2008 John Wiley & Sons, Ltd.
Wave propagation velocity under a vertically vibrated surface foundation
Authors: Ahn Jaehun , Biscontin Giovanna , Roësset Jose M. 
Published: December 2008

AbstractThe ultimate objective of the research conducted by the authors is to explore the feasibility of determining reliable in situ values of soil modulus as a function of strain. In field experiments, an excitation is applied on the ground surface using large‐scale shakers, and the response of the soil deposit is recorded through receivers embedded in the soil. The focus of this paper is on the simulation and observation of signals that would be recorded at the receiver locations under idealized conditions to provide guidelines on the interpretation of the field measurements. Discrete models are used to reproduce one‐dimensional and three‐dimensional geometries. When the first times of arrival are detected by receivers under the vertical impulse, they coincide with the arrival of the P wave; therefore related to the constrained modulus of the material. If one considers, on the other hand, phase differences between the motions at two receivers, the picture is far more complicated and one would obtain propagation velocities, function of frequency and measuring location, which do not correspond to either the constrained modulus or Young's modulus. It is necessary then to conduct more rigorous and complicated analyses in order to interpret the data. This paper discusses and illustrates these points. Copyright © 2008 John Wiley & Sons, Ltd.