bluuebunny/crossref_metadata_2025_split huggingface dataset:
Isothermal and Non‐Isothermal Crystallization Kinetics and Morphology of Poly(trimethylene terephthalate)/Multiwalled Carbon Nanotube Composites
Authors: Gupta Anju , Choudhary Veena 
Published: March 2010

AbstractSummary: Multiwalled carbon nanotubes (MWCNTs) synthesized using chemical vapor deposition method were dispersed in poly(trimethylene terephthalate) (PTT, Mv = 88,000) by melt compounding technique using DMS microcompounder. The nanocomposites consisting of varying amounts of MWCNTs were characterized by differential scanning calorimetry (DSC), wide‐angle X‐ray diffraction (WAXD), Raman spectroscopy, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The effect of carbon nanotubes on the crystallization behavior (under isothermal and non isothermal crystallization conditions) of PTT was studied using DSC. The presence of carbon nanotubes didn't show any significant effect on crystallization temperature of PTT matrix under non‐isothermal conditions. Crystallization studies under isothermal conditions were carried out at different temperatures i.e 185, 190, 195 and 200 °C. Complete crystallization was observed within 60 sec at 185 °C whereas at 200 °C, longer time was required for complete crystallization. Crystal growth was also investigated using hot stage polarizing microscope (PLM). The effect of annealing time at 200 °C was investigated in the presence as well as in the absence of varying amounts of MWCNTs. Spherulitic growth was seen and the spherulite size in all the samples increased with annealing time. Morphological characterization using SEM and TEM showed a uniform dispersion of MWCNTs and poor compatibility with PTT matrix.
Rheological Study Bringing New Insights into PET/PC Reactive Blends
Authors: Pereira Patrícia S.C. , Mendes Luis C. , Ramos Valéria D. 
Published: March 2010

AbstractSummary: Extruded poly(ethylene terephthalate)/polycarbonate (PET/PC) blends, with/without cobalt catalyst and at different polymer ratios, were prepared. Rheological behaviour was discussed in terms of storage (G′) and loss (G″) moduli, loss tangent (Tan δ) and viscosity (η). Both G′ and G″ increased as a function of frequency for all blends. PET was the matrix in the blends with 80 and 50 wt% of polyester but in the PC rich‐blend an inversion was observed. In all cases, lower Tan δ values were achieved at high frequencies. The viscosity behaviour showed a catalyst dependency. PET dictated the rheological properties of the blends without catalyst whereas PC governed blends with catalyst. Alcoholysis and acidolysis reactions plus a transesterification reaction occurred on the interface was dependent on the matrix component. These reactions seem to occur at higher extent in blends in which PET is the matrix but the inverse happened in the PC rich‐blend.
Structure and Properties of Multilayered PET/PC Composites
Authors: Adhikari Rameshwar , Seydewitz Volker , Löschner Katrin , Michler Goerg H. , Hiltner Anne , Baer Eric 
Published: March 2010

AbstractSummary: With the aid of layer multiplying coextrusion techniques, polymer composites comprising up to thousand of uniform and alternating layers polyethylene terephthalate (PET) and polycarbonate (PC) were produced. Morphology and micromechanical deformation processes in these composites were investigated by means of transmission electron microscopy (TEM) and atomic force microscopy (AFM). In particular, the effect of thickness of individual layers on the large strain deformation micromechanisms was analyzed. On decreasing the thickness of individual polymer layers, a transition in deformation mechanism from two‐component behaviour (i.e. the localization of shear bands in individual layer) to one‐component‐like behaviour (with the shear bands passing unhindered through different layers) was observed at the layer thickness of ca. 1 µm. On further decreasing the layer thickness below 100 nm, the composites exhibited homogeneous plastic deformation (i.e. no localization of deformation). In contrast to pure PET, even after long annealing, the composites showed tough behaviour during tensile loading.
Dielectric Relaxation Phenomena and Electric Properties of Conductive Composite Polyurethane/Polyaniline Films
Authors: Bouanga C. Vanga , Fatyeyeva K. , Baillif P.‐Y. , Khaokong C. , Pilard J.‐F. , Tabellout M. 
Published: March 2010

AbstractSummary: Composite polyurethane/polyaniline (PU/PANI) films have been chemically prepared by oxidative in‐situ polymerization of aniline inside the previously swelled PU film. Swelling kinetic studies have shown that for PU films the swelling degree of aniline is 25 wt.%. The dielectric and electrical properties of the composite films were measured using dielectric relaxation spectroscopy and four‐probe method. Dielectric measurements as a function of temperature and frequency revealed the presence of a relaxation process for the composite PU/PANI‐HCl film. This relaxation was explained in terms of interfacial polarization due to the double‐layered structure of the composite film. The activation energy values found by dielectric and electrical measurements are close and this result confirms the conducting character of the PANI containing layer.
Corrosion behaviour of stainless steels after low temperature thermochemical treatment
Authors: Spies H.‐J. , Eckstein Ch. , Biermann H. , Franke A. 
Published: March 2010

AbstractThe corrosion behaviour of nitrided, carburised and nitrocarburised samples of the steels X2CrNiMo17‐12‐2 (AISI 316L) and X2CrNiMoN22‐5‐3 (UNS 31803) was tested with electrochemical methods. Generally the current density potential curves of the samples are highly sensitive on the chromium depletion of the matrix due to the precipitation of chromium nitrides at the grain boundaries. It was observed that in this case, especially in 0.05M sulphuric acid, the passive current density in the complete range of the current density potential curve increases considerably. A criterion derived for the beginning of the decomposition of the expanded austenite allows the determination of its stability in dependence on the treatment temperature and time. The expanded carbon austenite has a higher thermal stability compared to the expanded nitrogen austenite. By controlled sequential removal of the samples surfaces the corrosion behaviour into the depth of the surface layers was investigated.Das Korrosionsverhalten nitrierter, carburierter und nitrocarburierter Proben der Stähle X2CrNiMo17‐12‐2 (AISI 316L) und X2CrNiMoN22‐5‐3 (UNS 31803) wurde mit elektrochemischen Methoden untersucht. Die Stromdichte‐Potenzial‐Kurven reagierten sehr empfindlich auf eine Chromverarmung der Matrix durch die Ausscheidung von Chromnitriden an Korngrenzen. Es wurde beobachtet, dass sich besonders bei den in 0,05M Schwefelsäure aufgenommenen Stromdichte‐Potenzial‐Kurven die Passivstromdichte im gesamten Bereich deutlich erhöhte. Ein daraus abgeleitetes Kriterium für den beginnenden Zerfall des expandierten Austenites ermöglicht eine Beschreibung seiner Stabilität in Abhängigkeit von den Behandlungsbedingungen. Der expandierte Kohlenstoffaustenit besitzt eine höhere thermische Stabilität als der expandierte Stickstoffaustenit. Durch kontrollierte Schichtabträge wurde das Korrosionsverhalten der Randschicht mit wachsendem Oberflächenabstand untersucht.
Sythhesis of coral‐like and spherical nanoparticles of barium titanate using factorial and Taguchi experimental design
Authors: Edrissi M. , Hosseinabadi H. Arabian 
Published: March 2010

AbstractHigh purity barium titanate (BaTiO3) nanoparticle and its coral like architectures were synthesized in a laboratory scale from BaO and TiCl4 by microwave hydrothermal processing using a mixture of 0.1:2 volume ratio of Triethanalamine and distilled deionized water. The products were characterized by XRD, LLS, SEM and wet chemical analysis. The size of barium titanate particles was in the range of 5–25 nm with average particle size of 15.5 nm. The two dimensional coral – like product had the diameter of (3–18 nm and length of 140–420 nm). The experiments were designed to fulfill the 23 factorial and L4 Taguchi designs. Data analysis was performed using MINITAB software.
KRAS mutant lung cancer cells are differentially responsive to MEK inhibitor due to AKT or STAT3 activation: Implication for combinatorial approach
Authors: Yoon Young‐Kwang , Kim Hwang‐Phill , Han Sae‐Won , Oh Do Youn , Im Seock‐Ah , Bang Yung‐Jue , Kim Tae‐You 
Published: March 2010

AbstractKRAS is frequently mutated in nonsmall cell lung cancer (NSCLC), resulting in the activation of the MAPK/ERK kinase (MEK)/ERK pathway. High‐throughput mutation profile has shown that lung cancer frequently harbors comutation of cancer‐related genes. Therefore, given that cancer cells have multiple genetic alterations, combinatorial therapeutic strategy is demanded for effective cancer therapy. To address this, we first characterized MEK dependence in four NSCLC cells. Two cells (H358, A549) carried KRAS mutation only, and the other two (H23, H157) harbored comutation of KRAS/PTEN. H358 cells with KRAS mutation only were sensitive to MEK inhibition. However, the other KRAS mutant A549 cells were resistant to MEK inhibition. Previously, we have shown that dual inhibition of EGFR and MEK signaling shows a synergistic effect on KRAS mutant gastric cancer cells by suppressing compensatory activation of AKT. Here we also observed that this combination was effective in KRAS mutant A549 cells. However, the combination was ineffective in H23 and 157 cells with comutation of KRAS/PTEN. Compared to KRAS mutant/PTEN wild‐type cells, signal transducer and activator of transcription 3 (STAT3) was significantly activated following MEK inhibition in KRAS/PTEN comutant cells. Combined STAT3 inhibition by a JAK2 inhibitor or gene knockdown with MEK inhibition blocked STAT3 activation, synergistically suppressed cell growth, and induced apoptosis in comutant cells. Taken together, our study provides molecular insights that help explain the heterogeneous response to MEK inhibition in KRAS mutant lung cancers, and presents a rationale for the clinical investigation of combination of MEK and EGFR inhibitor or MEK and JAK2 inhibitor depending on PTEN status. © 2010 Wiley‐Liss, Inc.
Stimulators of AMP‐activated kinase (AMPK) inhibit seawater‐ but not cAMP‐induced oocyte maturation in a marine worm: Implications for interactions between cAMP and AMPK signaling
Authors: Stricker Stephen A. , Swiderek Lee , Nguyen Thanh 
Published: March 2010

AbstractPrevious studies have shown that elevations in intraoocytic cAMP prevent mammalian oocytes from maturing, whereas cAMP degradation allows these oocytes to begin maturation, as evidenced by the onset of oocyte nuclear disassembly (=“germinal vesicle breakdown”, GVBD). Moreover, such cAMP degradation not only reduces cAMP levels but also generates AMP, which in turn can stimulate AMP‐activated kinase (AMPK), a well‐documented inducer of GVBD in mice. Alternatively, in some marine invertebrates, intraoocytic cAMP triggers, rather than blocks, GVBD, and whether AMPK up‐ or downregulates maturation in these species has not been tested. Thus, AMPK was monitored in the nemertean worm Cerebratulus during GVBD stimulated by seawater (SW) or cAMP elevators. In oocytes lacking surrounding follicle cells, AMPK activity was initially elevated in immature oocytes but subsequently reduced during SW‐ or cAMP‐induced GVBD, given that the catalytic α‐subunit of AMPK in maturing oocytes displayed a decreased stimulatory phosphorylation at T172 and an increased inhibitory phosphorylation at S485/491. Accordingly, AMPK‐mediated phosphorylation of acetyl‐CoA carboxylase, a known target of active AMPK, also declined during maturation. Moreover, treatments with either ice‐cold calcium‐free seawater (CaFSW) or AMPK agonists dissolved in SW maintained AMPK activity and inhibited GVBD. Conversely, adding cAMP elevators to CaFSW‐ or SW‐solutions of AMPK activators restored GVBD while promoting S485/491 phosphorylation and AMPK deactivation. Collectively, such findings not only demonstrate for the first time that intraoocytic AMPK can block GVBD in the absence of surrounding follicle cells, but these results also provide evidence for a novel GVBD‐regulating mechanism involving AMPK deactivation by cAMP‐mediated S485/491 phosphorylation. Mol. Reprod. Dev. 77: 497–510, 2010. © 2010 Wiley‐Liss, Inc.
A note on the online nature of the railway delay management problem
Authors: Kliewer Natalia , Suhl Leena 
Published: March 2010

AbstractUnavoidable disruptions induce the necessity of delay management in timetable‐driven passenger rail traffic. Minimizing the negative consequences of delays becomes one of the most relevant challenges for the economic success, as it directly affects the timeliness of passengers, which is a core indicator of customer satisfaction. In this article, we evaluate and compare various delay management strategies in a passenger railway network. A simulator has been implemented to generate delays and perform operations control decisions to resolve connection conflicts induced through passenger connections involving delayed trains. We compare dispatching strategies based on mathematical optimization with simple rule‐based strategies. Simulation runs with a timetable from the long‐distance passenger traffic of German Railways show that, due to the online nature of this decision problem, a simple waiting time rule strategy can outperform a strategy where the operations are reoptimized online after each disruption. © 2010 Wiley Periodicals, Inc. NETWORKS, 2011
Experimental study of speed up techniques for timetable information systems
Authors: Bauer Reinhard , Delling Daniel , Wagner Dorothea 
Published: March 2010

AbstractIn recent years, many speed up techniques for DIJKSTRA Algorithm have been developed. Unfortunately, research mainly focused on road networks although fast algorithms are also needed for other applications like timetable information systems. Even worse, the adaption of recently developed techniques to graphs deriving from timetable information problems is often more complicated than expected. In this work, we check whether results from road networks are transferable to timetable information systems. To this end, we present an extensive experimental study of the most prominent speed up techniques on inputs deriving from different applications. It turns out that recently developed techniques are much slower on graphs derived from timetable information problems than on road networks. In addition, we gain interesting insights into the behavior of speed up techniques in general. © 2010 Wiley Periodicals, Inc. NETWORKS, 2011
An advanced boundary element method for solving 2D and 3D static problems in Mindlin's strain‐gradient theory of elasticity
Authors: Karlis G. F. , Charalambopoulos A. , Polyzos D. 
Published: March 2010

AbstractAn advanced boundary element method (BEM) for solving two‐ (2D) and three‐dimensional (3D) problems in materials with microstructural effects is presented. The analysis is performed in the context of Mindlin's Form‐II gradient elastic theory. The fundamental solution of the equilibrium partial differential equation is explicitly derived. The integral representation of the problem, consisting of two boundary integral equations, one for displacements and the other for its normal derivative, is developed. The global boundary of the analyzed domain is discretized into quadratic line and quadrilateral elements for 2D and 3D problems, respectively. Representative 2D and 3D numerical examples are presented to illustrate the method, demonstrate its accuracy and efficiency and assess the gradient effect on the response. The importance of satisfying the correct boundary conditions in gradient elastic problems is illustrated with the solution of simple 2D problems. Copyright © 2010 John Wiley & Sons, Ltd.
Differential proteomic analysis using iTRAQ reveals changes in thylakoids associated with Photosystem II‐acquired thermotolerance in Synechocystis sp. PCC 6803
Authors: Rowland John G. , Simon William J. , Nishiyama Yoshitaka , Slabas Antoni R. 
Published: March 2010

AbstractGrowth temperature has a marked influence on the thermotolerance of photosystem II (PSII), which is the most heat‐sensitive component of photosynthesis. Using Synechocystis sp. PCC 6803 we have established that thylakoids isolated from cells grown at 38°C have a greater degree of thermotolerance than those isolated from cells grown at 25°C. Reconstitution experiments using Triton X‐100 protein extracts of these thylakoids added to Triton‐treated thylakoid membranes further indicated that the 38°C Triton extract contains proteins that are directly capable of enhancing PSII thermotolerance. We have used 4‐plex iTRAQ, extensive off‐line fractionation and sample re‐injection to comprehensively identify the differences between these two preparations that may be responsible for the observed effects on PSII thermotolerance. This has resulted in the reproducible identification of 168 proteins out of a total of 385 distinct proteins. Our results have identified 15 proteins whose levels are increased in extracts that result in increased thermotolerance of PSII and 33 proteins whose levels decrease. Notably, components of the cytochrome b6/f and NADH dehydrogenase complexes, crucial components in electron transport, are approximately twofold more abundant in 38°C thylakoid extracts. The possible biological importance of these changes is discussed.
Polymethine cyanine dyes in β‐cyclodextrin solution: multiple equilibria and chemical oxidation
Authors: Barros Teresa C. , Toma Sergio H. , Toma Henrique E. , Bastos Erick L. , Baptista Mauricio S. 
Published: March 2010

AbstractAbsorption and fluorescence spectroscopy, electrochemical techniques, and semiempirical calculations were employed to characterize the multiple complexation equilibria between two polymethine cyanine dyes (IR‐786 and Indocyanine green‐ICG, S) and β‐cyclodextrin (β‐CD, L), as well as the chemical reactivity of the complexed and uncomplexed species against the oxidizing agents hypochlorite (HC) and hydrogen peroxide (HP). IR‐786 dimerization is favored with the increase in β‐CD concentration in the form of (SL)2 complexes. In the case of ICG, free dimers (D) and SL complexes are favored. Both IR‐786 and ICG react and discolor in the presence of HC and HP. For IR‐786, the reaction with HP and HC proceeds with observed rate constants of 10−3 and 0.28 s−1 and second‐order rate constants (k2) of ∼10−3 and 104 M−1s−1, respectively. The intermediate species observed in the bleaching reactions of IR‐786 and ICG were shown, by cyclic voltammetry and VIS absorption, to result from one electron oxidation. IR‐786 complexed with β‐CD is protected against bleaching in the presence of HP and HC by factors of 20 and 4, respectively. This protection was not observed in ICG complexes. Superdelocalizability profile of both dyes and frontier orbital analysis indicates that β‐CD does not protect ICG from oxidation by HP or HC, whereas the 2:2 IR‐786/β‐Cd complex is able to avoid the oxidation of IR‐786. We concluded that the decrease in the chemical reactivity of the dyes against oxidant agents in the presence of β‐CD is due to the formation of (SL)2 complexes. Copyright © 2010 John Wiley & Sons, Ltd.
Factors correlated with fatigue in breast cancer survivors undergoing a rehabilitation course, Denmark, 2002–2005
Authors: Schultz Simon Lawaetz , Dalton Susanne Oksbjerg , Christensen Jane , Carlsen Kathrine , Ross Lone , Johansen Christoffer 
Published: March 2010

AbstractObjective: The aim of this prospective cohort study was to identify factors associated with fatigue in women with breast cancer who attended a 6‐day rehabilitation course. Furthermore, to investigate level of fatigue 1 year after the rehabilitation course, after accounting for baseline fatigue levels. Methods: Between 2002 and 2005 we included 775 women with breast cancer and measured fatigue, emotional functioning and insomnia using the EORTC subscales and sociodemographics from a baseline questionnaire prior to participation in the rehabilitation course. Information on disease‐specific and treatment factors was obtained from a nationwide clinical database. From the 12‐month follow‐up questionnaire we obtained level of fatigue. We estimated the influence of factors on the relative risk for a 10‐points increase in fatigue score in generalised linear models. For the analysis of fatigue at 12 months follow‐up we added fatigue level at baseline and relapse since baseline. Results: Higher tumour grade and insomnia predicted higher levels of fatigue, whereas better emotional functioning was associated with lower levels. After 12 months of follow‐up fatigue levels were associated with level at baseline and with emotional functioning, insomnia, relapse and being on sick leave or unemployed. Emotional level, insomnia and high grade were associated with level of fatigue. After 1 year, a high level at baseline, insomnia and low emotional functioning was associated with greater fatigue. Conclusions: These longitudinal results support that cancer‐related fatigue can be a persistent phenomenon and that focus on psychological distress and sleeping problems might be beneficial in these women. Copyright © 2010 John Wiley & Sons, Ltd.
Ku86 is important for TrkA overexpression‐induced breast cancer cell invasion
Authors: Lagadec Chann , Romon Rodrigue , Tastet Christophe , Meignan Samuel , Com Emmanuelle , Page Adeline , Bidaux Gabriel , Hondermarck Hubert , Le Bourhis Xuefen 
Published: March 2010

AbstractPurpose: We have recently shown that breast tumors express high levels of TrkA compared with normal breast tissues, with TrkA overexpression enhancing breast cancer cell invasion in vitro and metastasis in animal models. In this study, we tried to identify molecules involved in TrkA overexpression‐mediated biological effects in breast cancer cells.Experimental design: We used a proteomic‐based approach to identify proteins involved in TrkA overexpression‐stimulated invasion of MDA‐MB‐231 breast cancer cells. Proteins from control and TrkA overexpressing cells were separated using a cup‐loading two‐dimensional electrophoresis system before MALDI and LC‐MS/MS mass spectrometry analysis.Results: Among several putative regulated proteins, Ku86 was found increased in TrkA overexpressing cells. Moreover, Ku86 was co‐immunoprecipitated with TrkA, suggesting the interaction of these two proteins in TrkA overexpressing cells. Interestingly, inhibition with small‐interfering RNA and neutralizing antibodies showed that Ku86 was required for TrkA‐stimulated cell invasion.Conclusions and clinical relevance: These data allowed the identification of Ku86 as a new player involved in metastasis in breast cancer cells. Our findings suggest that TrkA and its down stream signaling pathways should be regarded as potential new targets for the development of future breast cancer therapy.