bluuebunny/crossref_metadata_2025_split huggingface dataset:
Quantitative phosphoproteomics of transforming growth factor‐β signaling in colon cancer cells
Authors: Ali Naveid A. , Molloy Mark P. 
Published: June 2011

AbstractThe transforming growth factor‐β (TGF‐β) signaling pathway progresses through a series of protein phosphorylation regulated steps. Smad4 is a key mediator of the classical TGF‐β signaling pathway; however, reports suggest that TGF‐β can activate other cellular pathways independent of Smad4. By investigating the TGF‐β‐regulated phosphoproteome, we aimed to uncover new functions controlled by TGF‐β. We applied titanium dioxide to enrich phosphopeptides from stable isotope labeling with amino acids in cell culture (SILAC)‐labeled SW480 cells stably expressing Smad4 and profiled them by mass spectrometry. TGF‐β stimulation for 30 min resulted in the induction of 17 phosphopeptides and the repression of 8 from a total of 149 unique phosphopeptides. Proteins previously not known to be phosphorylated by TGF‐β including programmed cell death protein 4, nuclear ubiquitous casein and cyclin‐dependent kinases substrate, hepatoma‐derived growth factor and cell division kinases amongst others were induced following TGF‐β stimulation, while the phosphorylation of TRAF2 and NCK‐interacting protein kinase are examples of proteins whose phosphorylation status was repressed. This phosphoproteomic screen has identified new TGF‐β‐modulated phosphorylation responses in colon carcinoma cells.
A new terpyridine tethered polythiophene: Electrosynthesis and characterization
Authors: Manca Paola , Pilo Maria I. , Casu Giovanni , Gladiali Serafino , Sanna Gavino , Scanu Roberta , Spano Nadia , Zucca Antonio , Zanardi Chiara , Bagnis Diego , Valentini Luca 
Published: June 2011

AbstractA novel polythiophene bearing a pendant terpyridine moiety has been synthesized by electrochemical polymerization of a new thiophene monomer, namely 4′‐(2,2′:5′,2″‐terthien‐3′‐ethynyl)‐2,2′:6′,2″‐terpyridine (TAT). The insertion of a conjugated ethynyl spacer between the terthiophene and the terpyridine fragments provides for an effective extension of the delocalization of electrons within the structural unit and the polymer as a whole. The synthesis and characterization of the relevant monomer, the electrosynthesis of the corresponding polymer and its electrochemical, UV–visible spectroelectrochemical and IR characterization are described. Finally, a comparison between the electrochemical, spectroscopic, and spectroelectrochemical properties of PTAT and the analogue, saturated‐spacer PTTT (TTT = 4′‐[(2,2′:5′,2″‐terthien‐3′‐yl)methoxy]‐2,2′:6′,2″‐terpyridine) polymer is discussed. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011
Preparation of novel suspensions of ZnO/living block copolymer latex nanoparticles via pickering emulsion polymerization and their long term stability
Authors: Chou I‐Chen , Lee Chia‐Fen , Chiu Wen‐Yen 
Published: June 2011

AbstractIn this work, we present the first Pickering emulsion polymerization with a controlled/living character. Pickering emulsion polymerization in the presence of a novel suspension of zinc oxide/poly(sodium 4‐styrenesulfonate) (ZnO/PSS−) nanocomposite particles was applied to prepare ZnO/living block copolymer latexes. In the emulsion system, 1,1‐diphenylethene (DPE)‐controlled radical polymerization of poly(methyl methacrylate)‐b‐poly(butyl acrylate) (PMMA‐b‐PBA) was proceeded in oil phase. The nanocomposite particles of ZnO/PSS− with an average diameter of 20 nm and negatively charged zeta potential around −30 mV were synthesized via hydrothermal method then served as an effective emulsion stabilizer at the oil/water interface. Living polymerization was carried out using DPE‐capped PMMA as the macroinitiator and PMMA‐b‐PBA block copolymer latex was successfully prepared with coverage of ZnO/PSS− nanoparticles. Narrow size distributions of the droplets as well as latex particles were obtained, and the livingness of block copolymers was comparable to that of emulsions stabilized by conventional surfactants. The controlled/living character in Pickering emulsion polymerization was slightly influenced by the amount of PSS− immobilized into the ZnO/PSS− nanoparticles, whereas it was significantly influenced by the weight ratios between ZnO/PSS− and oil phase. The Pickering latexes showed excellent long term stability against either coalescence or sedimentation over several months. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011
Optimization of the shape memory effect in shape memory polymers
Authors: Sun L. , Huang W. M. , Wang C. C. , Zhao Y. , Ding Z. , Purnawali H. 
Published: June 2011

AbstractIn this article, we show that given a thermoresponsive shape memory polymer, it is possible to alter a number of its properties, such as the recovery temperature, shape fixity ratio, maximum recovery stress, and final recovery stress (and even a right combination of some of them, e.g., the maximum recovery stress and final recovery stress), simply by means of selecting the programming temperature to achieve optimized performance. Some concerns for the implementation in real engineering practice are also discussed. Although the focus is on the case of a fixed maximum strain in programming, alternative programming approaches can be investigated in a similar way for optimized performance as well. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011
Quantitation of protein–protein interactions by thermal stability shift analysis
Authors: Layton Curtis J. , Hellinga Homme W. 
Published: June 2011

AbstractThermal stability shift analysis is a powerful method for examining binding interactions in proteins. We demonstrate that under certain circumstances, protein–protein interactions can be quantitated by monitoring shifts in thermal stability using thermodynamic models and data analysis methods presented in this work. This method relies on the determination of protein stabilities from thermal unfolding experiments using fluorescent dyes such as SYPRO Orange that report on protein denaturation. Data collection is rapid and straightforward using readily available real‐time polymerase chain reaction instrumentation. We present an approach for the analysis of the unfolding transitions corresponding to each partner to extract the affinity of the interaction between the proteins. This method does not require the construction of a titration series that brackets the dissociation constant. In thermal shift experiments, protein stability data are obtained at different temperatures according to the affinity‐ and concentration‐dependent shifts in unfolding transition midpoints. Treatment of the temperature dependence of affinity is, therefore, intrinsic to this method and is developed in this study. We used the interaction between maltose‐binding protein (MBP) and a thermostable synthetic ankyrin repeat protein (Off7) as an experimental test case because their unfolding transitions overlap minimally. We found that MBP is significantly stabilized by Off7. High experimental throughput is enabled by sample parallelization, and the ability to extract quantitative binding information at a single partner concentration. In a single experiment, we were able to quantify the affinities of a series of alanine mutants, covering a wide range of affinities (∼ 100 nM to ∼ 100 μM).
Penicillin‐binding protein 5 can form a homo‐oligomeric complex in the inner membrane of Escherichia coli
Authors: Skoog Karl , Bruzell Filippa Stenberg , Ducroux Aurélie , Hellberg Mårten , Johansson Henrik , Lehtiö Janne , Högbom Martin , Daley Daniel O. 
Published: June 2011

AbstractPenicillin‐binding protein 5 (PBP5) is a DD‐carboxypeptidase, which cleaves the terminal D‐alanine from the muramyl pentapeptide in the peptidoglycan layer of Escherichia coli and other bacteria. In doing so, it varies the substrates for transpeptidation and plays a key role in maintaining cell shape. In this study, we have analyzed the oligomeric state of PBP5 in detergent and in its native environment, the inner membrane. Both approaches indicate that PBP5 exists as a homo‐oligomeric complex, most likely as a homo‐dimer. As the crystal structure of the soluble domain of PBP5 (i.e., lacking the membrane anchor) shows a monomer, we used our experimental data to generate a model of the homo‐dimer. This model extends our understanding of PBP5 function as it suggests how PBP5 can interact with the peptidoglycan layer. It suggests that the stem domains interact and the catalytic domains have freedom to move from the position observed in the crystal structure. This would allow the catalytic domain to have access to pentapeptides at different distances from the membrane.
Quantum gravity, flavour vacua and supersymmetry
Authors: Mavromatos N.E. 
Published: June 2011

AbstractI review a novel and non‐perturbative way of breaking Supersymmetry in the flavour sector of electrically neutral particles, as a result of flavour mixing in the presence of stringy quantum gravity space‐time foam backgrounds that violate Lorentz and CPT symmetries. In these models, part of the mixing may itself be induced dynamically by the interactions of the flavoured particles with the space‐time foam.
Composite photonic crystal cavities of macro porous silicon and lead sulfide thin films
Authors: Gutman Nadav , Osherov Anna , Golan Yuval , Sa'ar Amir 
Published: June 2011

AbstractWe report on the design and demonstration of novel photonic crystal (PC) cavities. The cavity active region is made of a macro‐porous silicon infiltrated with optically active lead sulfide thin films (emitting at a wavelength of about ∼2.9 µm), while the surrounding silicon PC acts as a mirror that confines the infrared light. The luminescence spectrum of the composite PC cavity presents a set of resonant frequencies associated with the cavity modes that overlap with the photonic stopbands of the host silicon PC.
Dislocations and stacking faults in hexagonal GaN
Authors: Batyrev I. G. , Sarney W. L. , Zheleva T. S. , Nguyen C. , Rice B. M. , Jones K. A. 
Published: June 2011

AbstractWe present experimental and theoretical results on extended defects of hexagonal GaN grown by metal organic vapour deposition (MOCVD). Transmission electron microscopy (TEM) measurements indicate the presence of 3 nm wide type I1 stacking faults (SFs) related to the MOCVD growth, and 2–4 nm SFs of unidentified type related to the ion implantation. We simulated infinite SFs of different types I1, I2 and I3. First principles calculations were used to model Shockley partial dislocations, the core structure of the dislocations and intrinsic SFs. We estimate defect level positions and the formation energy of the infinite SFs. We also present results of the calculations and available experimental data on finite size SFs bounded by partial dislocations in wurtzite GaN. Calculation of the infinite SFs revealed shallow levels, but no deep levels. In the SFs bound by dislocations there are deep filled levels in the range of 0.4–0.8 eV from the valence band maximum (VBM) located at the atoms of the 90° dislocations. We also calculated the segregation of the C, n‐dopant, Si or O and the p‐dopant, Mg, to the dislocations and SFs. The effect of the segregation is found to be stronger for the SFs with partials. The results of the calculations are correlated with the experimental data on GaN obtained from high resolution TEM and Hall measurements. We suggest mechanisms of the formation of the SFs I1 and I2 after ion implantation and high temperature anneal and explain the difficulties of p‐type doping with the formation of the extended defects.
Synthesis and optical properties of Mn doped ZnO thin films
Authors: Chvostová Dagmar , Dejneka Alexandr , Hubička Zdeněk , Churpita Alexander , Bykov Pavlo , Jastrabík Lubomír , Trepakov Vladimir A. 
Published: June 2011

AbstractStudy of optical and electrical properties of Mn doped ZnO films deposited by atmospheric barrier torch discharge technique on SiO2 substrates is reported for a wide range of Mn concentration (0.2–20 at.%). It was found that the growth of all Mn‐doped ZnO films contains secondary Mn2O3 phase even for the lowest manganese concentration (0.2%). When Mn concentration is in the range 0.2–4%, this secondary Mn2O3 phase does not conspicuously affect Raman spectra of ZnO evidencing that Mn is mostly incorporated into the ZnO host matrix. Increase of Mn concentration (8–20%) is accompanied by formation of Mn2O3 clusters manifesting itself in the appearance of a corresponding mode in the Raman spectra. These clusters influence dramatically optical and electrical properties of the films. The Mn “solubility limit” for the films growth technique used is determined to be near 8%.
A study of intermixing in perovskite superlattices by simulation‐supported cs‐corrected HAADF‐STEM
Authors: Hillebrand Reinald , Pippel Eckhard , Hesse Dietrich , Vrejoiu Ionela 
Published: June 2011

AbstractIn this paper, we present and interpret high‐angle annular dark field scanning transmission electron microscopy (HAADF‐STEM) images of La0.7Sr0.3MnO3/SrRuO3 superlattices. The images were taken in a probe‐corrected (cs = 0) FEI microscope at 300 kV. We developed a simulation‐based technique to evaluate possible intermixing at the interfaces via Z‐contrast. The experimental and simulated image intensities across the interfaces are directly compared, where the gradients in the models are systematically varied. Different gradients in different sub‐lattices at the interfaces can clearly be distinguished by a best fit criterion.magnified imageColoured HAADF‐STEM image (V = 300 kV, cs = 0) of a La0.7Sr0.3MnO3/SrRuO3 layer structure.
Increasing the extraction efficiency of blue light emitting diodes via laser patterned Ga‐polar p‐GaN surface
Authors: Zuo Zhiyuan , Liu Duo , Zhang Baitao , He Jingliang , Liu Hong , Xu Xiangang 
Published: June 2011

AbstractWe report here the laser patterned Ga‐polar p‐GaN surface to improve the light extraction efficiency of GaN based blue light emitting diodes (LEDs) by using a pulsed UV laser in combination with a mirror scanner. The patterns created on p‐GaN are confirmed to be suitable for light extraction and a 34.9% enhancement of the electroluminescent (EL) emission intensity has been obtained. Detailed discussions on the effects of laser on LEDs and the angular dependence of the emission profile are also provided. This method could be extended to other III–V LEDs and LEDs on SiC for fabricating highly efficient LEDs.magnified image
The schematic of laser fabrication equipment, SEM image of patterned p‐GaN surface and guided‐modes extraction photograph of patterned GaN epilayer.
Traveling dipole domains in AlGaN/GaN heterostructures and the direct generation of millimeter‐wave oscillations
Authors: Yoder P. D. , Sridharan Sriraaman , Graham Samuel , Shen S.‐C. , Ryou J.‐H. , Dupuis R. D. 
Published: June 2011

AbstractA new paradigm is presented for the direct generation of self‐sustaining millimeter‐wave oscillations, based on the piezo‐ and ferroelectric properties of wurtzite III‐nitride materials. In contrast to Gunn diodes which exploit a bulk‐like active region, periodic oscillation is achieved in the proposed structures through the creation, propagation and collection of traveling dipole domains supported by fixed polarization charge and the associated two‐dimensional electron gas along the plane of a polar heterojunction. State‐of‐the‐art numerical simulation based on the synchronous full‐band ensemble Monte Carlo method is applied to study induced oscillations in a simple triode structure commonly used for AlGaN/GaN high electron mobility transistors. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Effects of annealing on 320 nm cathodoluminescence from hexagonal boron nitride powders
Authors: Hara Kazuhiko , Liu Xin , Yamauchi Manabu , Kawanishi Yasumasa , Kominami Hiroko , Nakanishi Yoichiro 
Published: June 2011

AbstractThe effect of annealing in various atmospheres (N2, H2, NH3 O2 and vacuum) on the 320 nm emission bands of hexagonal boron nitride (h‐BN) powders has been investigated by cathodoluminescence (CL). The CL intensity was decreased by annealing in the N2, H2and NH3 atmospheres at 1200 °C, with H2and NH3 having more effect than N2. On the other hand, the annealing in the O2 atmosphere increased the CL intensity remarkably at annealing temperatures higher than 800 °C. These results suggest that the oxygen located near the particle surface is related to the enhancement of the 320 nm bands in h‐BN. The highest CL intensity, which was obtained at an annealing temperature of 900 °C, reached to about one third of that measured for ZnS:Cu,Al phosphor under the same measurement conditions. The investigation of the powder annealed at higher temperatures in a vacuum indicated that the luminescent centers responsible for these emission bands are thermally stable up to about 1300 °C (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Vibrational Raman spectra of CdSx Se1‐x magic‐size nanocrystals
Authors: Dzhagan Volodymyr , Mel'nik Nikolai , Rayevska Olexandra , Grozdyuk Galyna , Strelchuk Viktor , Plyashechnik Olga , Kuchmii Stepan , Valakh Mykhailo 
Published: June 2011

AbstractResonant Raman scattering spectra of ultrasmall (<2 nm) magic‐size nanocrystals (NCs) are reported. The spectra of CdS and CdSx Se1‐x NCs, resonantly excited with 325 nm and 442 nm laser lines, correspondingly, reveal broad features in the range of bulk optical phonons. The relatively large width, ∼50 cm‐1, and downward shift, ∼20 cm‐1, of the Raman bands with respect to the longitudinal optical phonon in bulk crystals and large NCs are discussed based on the breaking of the translational symmetry and bond distortion in these ultrasmall NCs. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Composition dependence of unipolar resistance switching in TaOx thin films
Authors: Kurnia F. , Hadiyawarman  , Jung C. U. , Jung Ranju , Liu Chunli 
Published: June 2011

AbstractAmorphous TaOx thin films were deposited at different temperatures, and the resistance switching properties of the Pt/TaOx/Pt structure were investigated. X‐ray photoelectron spectroscopy showed that the amount of Ta2O5 in the film decreased and the content of Ta suboxides increased substantially when the growth temperature was increased. Unipolar resistance switching near the anode was stable only for TaOx film grown at room temperature. The experimental results revealed the critical effect of the film composition on the resistance switching behavior of TaOx films. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Review of cytomegalovirus shedding in bodily fluids and relevance to congenital cytomegalovirus infection
Authors: Cannon Michael J. , Hyde Terri B. , Schmid D. Scott 
Published: June 2011

SUMMARYCongenital cytomegalovirus (CMV) infections are a leading cause of sensorineural hearing loss (SNHL) and neurological impairment. Congenital transmission of CMV can occur with maternal primary infection, reactivation, or reinfection during pregnancy. We reviewed studies of CMV shedding in bodily fluids (defined as CMV detected by culture or CMV DNA detected by polymerase chain reaction). Following diagnosis at birth, children with congenital CMV infection exhibited the highest prevalences of CMV shedding (median = 80%, number of sample population prevalences [N] = 6) and duration of shedding, with a steep decline by age five. Healthy children attending day care shed more frequently (median = 23%, N = 24) than healthy children not attending day care (median = 12%, N = 11). Peak shedding prevalences in children occurred at 1–2 years of age, confirming that young children are the key transmission risk for pregnant women. CMV shedding among children was more prevalent in urine specimens than in oral secretions (median prevalence difference = 11.5%, N = 12). Adults with risk factors such as STD clinic attendance had higher shedding prevalences (median = 22%, N = 20) than adults without risk factors (median = 7%, N = 44). In adults with risk factors, CMV was shed more frequently in urine; in adults without risk factors genital shedding was most common. The prevalence of CMV shedding in nine sample populations of pregnant women increased with advancing gestation. In seven sample populations of children with congenital CMV infection, higher viral load at birth was consistently associated with an elevated risk of SNHL. Higher CMV viral load at birth also consistently correlated with the presence of symptoms of congenital CMV at birth. Published 2011. This article is a US Government work and is in the public domain in the USA.
A method for visualization of surface texture anisotropy in different scales of observation
Authors: Berglund J. , Wiklund D. , Rosén B.‐G. 
Published: June 2011

AbstractAnisotropy of functional surfaces can in many practical cases significantly influence the surface function. Tribological contacts in sheet forming and engine applications are good examples. This article introduces and exemplifies a method for visualization of anisotropy. In a single graph, surface texture properties related to the anisotropy as a function of scale are plotted. The anisotropy graph can be used to explain anisotropy properties of a studied surface such as texture direction and texture strength at different scales of observation. Examples of milled steel surfaces and a textured steel sheet surface are presented to support the proposed methodology. Different aspects of the studied surfaces could clearly be seen at different scales. Future steps to improve filtering techniques and an introduction of length‐scale analysis are discussed. SCANNING 33: 325–331, 2011. © 2011 Wiley Periodicals, Inc.
Discrimination of surface wear on obsidian tools using LSCM and RelA: pilot study results (area‐scale analysis of obsidian tool surfaces)
Authors: Stemp W. James , Chung Steven 
Published: June 2011

AbstractThis pilot study tests the reliability of laser scanning confocal microscopy (LSCM) to quantitatively measure wear on experimental obsidian tools. To our knowledge, this is the first use of confocal microscopy to study wear on stone flakes made from an amorphous silicate like obsidian. Three‐dimensional surface roughness or texture area scans on three obsidian flakes used on different contact materials (hide, shell, wood) were documented using the LSCM to determine whether the worn surfaces could be discriminated using area‐scale analysis, specifically relative area (RelA). When coupled with the F‐test, this scale‐sensitive fractal analysis could not only discriminate the used from unused surfaces on individual tools, but was also capable of discriminating the wear histories of tools used on different contact materials. Results indicate that such discriminations occur at different scales. Confidence levels for the discriminations at different scales were established using the F‐test (mean square ratios or MSRs). In instances where discrimination of surface roughness or texture was not possible above the established confidence level based on MSRs, photomicrographs and RelA assisted in hypothesizing why this was so. SCANNING 33: 279–293, 2011. © 2011 Wiley Periodicals, Inc.