bluuebunny/crossref_metadata_2025_split huggingface dataset:
Self‐assembly of ABA triblock copolymers based on functionalized polydimethylsiloxane and polymethyloxazoline
Authors: Theogarajan Luke , Li Hangsheng , Busse Karsten , Desai Salil , Kressler Jörg , Scholz Carmen 
Published: May 2010

AbstractThis study describes the responsive behavior of modified amphiphilic ABA triblock copolymers of polymethyloxazoline‐block‐poly(methylhydrosiloxane‐co‐dimethylsiloxane)‐block‐polymethyloxazoline (PMOX‐b‐P(MHS‐co‐DMS)‐b‐PMOX) when subjected to compression on the water surface or to ions in the water bulk phase. The hydrophobic middle block was functionalized with spacers bearing methyl 2‐hydroxybenzoate (Bz) or 18‐crown‐6 ether (Ce) groups. The behavior at the air–water interface was studied by measuring surface pressure versus mean molecular area (π–mmA) isotherms, and atomic force microscopy (AFM) was employed to investigate the morphology of Langmuir–Blodgett (LB) films after transfer to solid supports. Ion‐responsive self‐assembly was followed using light microscopy and can be understood on a molecular level by employing 1H NMR spectroscopy. The π‐mmA isotherm of PMOX‐b‐P(MHS‐co‐DMS)‐b‐PMOX‐44Bz at the air–water interface had an extended pseudo‐plateau at a surface pressure of ca 22 mN m−1 reflecting the coil to loop transformation of the hydrophobic middle block which was absent for the crown ether‐functionalized triblock copolymer. AFM images of LB films of PMOX‐b‐P(MHS‐co‐DMS)‐b‐PMOX‐44Bz showed dewetting effects of the polymer film after transfer to a silicon wafer. LB films of PMOX‐b‐P(MHS‐co‐DMS)‐b‐PMOX‐8Ce formed surface micelles having a size of ca 50–100 nm on the solid support. The ion sensitivities of the crown ether‐derivatized copolymers in solution were investigated by exposing polymeric vesicles to potassium, sodium and magnesium ions. Exposure to K+ and Na+ led to vesicle rupture and the formation of micro‐tubular structures, while Mg2+ had no effect on the vesicular structures as confirmed using light microscopy. Specific interactions between the crown ether‐derivatized polymer and ions were further elucidated from 1H NMR experiments that indicated that K+ coordinated with the crown ether causing the dense packing to subside and leading to solubilization of the polymer in water. Copyright © 2010 Society of Chemical Industry
Proteomic analysis of colonic mucosa in a rat model of irritable bowel syndrome
Authors: Ding Ying , Lu Bin , Chen Dongbo , Meng Lina , Shen Yan , Chen Shuo 
Published: May 2010

AbstractIrritable bowel syndrome (IBS) is one of the most common functional disorders of the gastrointestinal tract. It is characterized by abdominal pain and changes in bowel habits. Various studies have investigated the pathophysiologic processes underlying IBS, but the mechanism remains poorly understood. In the present study, we established an IBS model and identified differentially expressed proteins in colon tissue of IBS rats compared with healthy controls by 2‐D gel electrophoresis, MALDI‐TOF‐MS, and Western blot analysis. Our results showed that 13 of the 1396 protein spots on 2‐D gel were differently expressed between the IBS and control groups. Ontological analysis of these proteins revealed primary roles in catalytic activity (protein disulfide‐isomerase A3, glyoxalase I, cathepsin S, α‐enolase), structural support (cytokeratin 8), antioxidant activity (peroxiredoxin‐6), protein binding (transgelin, serpin peptidase inhibitor B5), and signal transduction (40S ribosomal protein SA). Protein disulfide‐isomerase A3 and cytokeratin 8 overexpression in IBS were confirmed by Western blot. The findings indicate that multiple proteins are involved in IBS processes that influence intestinal tract immunity, inflammation, and nerve regulation. Our study provides useful candidate genes and proteins for further investigation.
Identification of candidate nasopharyngeal carcinoma serum biomarkers by cancer cell secretome and tissue transcriptome analysis: Potential usage of cystatin A for predicting nodal stage and poor prognosis
Authors: Chang Kai‐Ping , Wu Chih‐Ching , Chen Hua‐Chien , Chen Shu‐Jen , Peng Pei‐Hua , Tsang Ngan‐Ming , Lee Li‐Yu , Liu Shiau‐Chin , Liang Ying , Lee Yun‐Shien , Hao Sheng‐Po , Chang Yu‐Sun , Yu Jau‐Song 
Published: May 2010

AbstractNasopharyngeal carcinoma (NPC) is usually diagnosed at advanced clinical stages, resulting in poor outcomes. To discover serum biomarkers for improved NPC diagnosis and/or management, we simultaneously analyzed the NPC cell secretome and tissue transcriptome to identify candidate genes/proteins that are highly upregulated in NPC tissues and also secreted/released from NPC cells. Among the 30 candidates identified, 11 proteins were chosen for further validation using the serum samples from NPC patients and healthy controls, including cystatin A, cathepsin B, manganese superoxide dismutase and matrix metalloproteinase 2. The results showed that serum levels of all the four proteins were indeed higher in NPC patients versus healthy controls and that the use of a three‐marker panel (cystatin A, manganese superoxide dismutase and matrix metalloproteinase 2) can contribute to a better NPC detection than each marker alone. In addition, a higher pretreated serum level of cystatin A was found to be associated with a higher nodal stage and poorer prognosis of NPC patients and cystatin A could modulate the migration and invasion of NPC cells in vitro. Altogether, our results indicate that analysis of both the cancer cell secretome and tissue transcriptome is a feasible strategy for efficient identification of novel NPC serum marker panel.
Performance of ZDOCK and ZRANK in CAPRI rounds 13–19
Authors: Hwang Howook , Vreven Thom , Pierce Brian G. , Hung Jui‐Hung , Weng Zhiping 
Published: May 2010

AbstractWe report the performance of the ZDOCK and ZRANK algorithms in CAPRI rounds 13–19 and introduce a novel measure atom contact frequency (ACF). To compute ACF, we identify the residues that most often make contact with the binding partner in the complete set of ZDOCK predictions for each target. We used ACF to predict the interface of the proteins, which, in combination with the biological data available in the literature, is a valuable addition to our docking pipeline. Furthermore, we incorporated a straightforward and efficient clustering algorithm with two purposes: (1) to determine clusters of similar docking poses (corresponding to energy funnels) and (2) to remove redundancies from the final set of predictions. With these new developments, we achieved at least one acceptable prediction for targets 29 and 36, at least one medium‐quality prediction for targets 41 and 42, and at least one high‐quality prediction for targets 37 and 40; thus, we succeeded for six out of a total of 12 targets. Proteins 2010. © 2010 Wiley‐Liss, Inc.
Simulations of laser diodes with nonpolar InGaN multi‐quantum‐wells
Authors: Li Z. Q. , Li Z. M. Simon , Piprek Joachim 
Published: May 2010

AbstractSimulations of the characteristics of laser diodes (LD) with non‐polar and InGaN multi‐quantum‐wells (MQW) have been conducted in multi‐dimensional drift‐diffusion model. The strain coefficients of the QWs of arbitrary crystal‐orientations are obtained by minimizing the total strain energy. Electronic structure and optical gain of non‐polar InGaN QWs are calculated by the 6x6 k.p theory. Finally by integrating the gain and effective mass models of non‐polar InGaN QW into our LASTIP software package, we simulated the performance of the laser diodes with non‐polar MQWs, and the results are compared with the experiments. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Modelling of cubic AlxGa1–xN/GaN resonant tunnel diode structures
Authors: Zainal N. , Walker P. , Kent A. J. 
Published: May 2010

AbstractThe current‐voltage characteristics of a cubic AlxGa1‐xN/GaN double‐barrier resonant tunnelling diode (DBRTD) have been calculated with the variation of band offset, well width, barrier composition and barrier thickness parameters. Using the ratio of the current magnitude at the resonant peak to the width of the resonance as a figure of merit for the device, the optimum barrier thickness for a given composition is determined. Finally, a promising cubic AlxGa1‐xN/GaN DBRTD structure with optimum parameters is proposed. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
In situ bow monitoring: towards uniform blue and green InGaN/GaN quantum well structures grown on 100 mm sapphire substrates by MOVPE
Authors: Cheng Kai , Degroote S. , Leys M. , Zhang L.Y. , Derluyn J. , Germain M. , Borghs G. 
Published: May 2010

AbstractIn this work, a home‐made curvature measurement tool is used to monitor the wafer bow evolution during epitaxy of blue‐green quantum well structures grown on 100 mm sapphire substrates. A single position detector is installed to real‐time record both the surface reflectance and the wafer bowing simultaneously. Due to the low thermal conductivity of sapphire, a very large wafer bow was observed during high temperature thermal annealing before growth. The large wafer bow may lead to non‐uniformity of both GaN buffer layers and InGaN/GaN multiple quantum wells (MQW). Careful temperature profile tuning and control of wafer bowing are critical to improve the layer uniformity. With the assistance of this in‐situ bow monitoring tool, uniform and high efficiency blue/green InGaN/GaN quantum well structures have been demonstrated on 100 mm sapphire substrates by Metal Organic Vapour Phase Epitaxy (MOVPE). The internal quantum efficiency (IQE) of the blue MQW structure is as high as 76%. This is deduced from temperature dependent (4 K‐300 K) and power dependent photoluminescence (PL) measurements. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
HVPE growth of a ‐plane GaN on a GaN template (110)Si substrate
Authors: Tanikawa Tomoyuki , Suzuki Noriyuki , Honda Yoshio , Yamaguchi Masahito , Sawaki Nobuhiko 
Published: May 2010

AbstractHVPE growth of a‐plane (11‐20)GaN was demonstrated. GaN growth was initiated from template GaN stripes, and each GaN stripes coalesced to get uniform crystal. At conventional growth temperature of 1000 °C, melt back etching was observed in GaN and surface morphology was poor. By lowering growth temperature to 870 °C, this phenomenon did not occur and morphology was also improved. NH3 flow rate was not effective on the morphology. RMS value was 0.78 nm to show the stability of the formation of surface. The dark spot density was as low as 107 cm‐2. We found that most of dislocations were attributed to the coalescence of template stripes. CL spectrum showed the strong DBE peak. DAP emission and yellow luminescence were much weaker than DBE peak. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Effective mass of InN estimated by Raman scattering
Authors: Kim Jung Gon , Kamei Yasuhito , Hasuike Noriyuki , Harima Hiroshi , Kisoda Kenji , Sasamoto Kouhei , Yamamoto Akio 
Published: May 2010

AbstractWe have estimated the longitudinal effective mass (m‖) of electron in n‐type InN films by Raman scattering. The samples were grown by MOVPE (metal organic vapor phase epitaxy) with free carrier concentration of n =6.7×1018‐9.9×1018 cm‐3 according to Hall measurement. A weak Raman signal observed at ∼430 cm‐1 at room temperature was sharpened and shifted to higher frequency toward the A1(TO)‐phonon mode at 447 cm‐1 with increasing n. This mode was assigned to the lower branch (L‐) of the longitudinal‐optic‐phonon‐plasmon‐coupled (LOPC) mode. The line shape was carefully analyzed by a semi‐classical line‐shape fitting analysis assuming deformation potential and electro‐optic coupling mechanisms for the light scattering process. A line‐shape fitting analysis was conducted by adjusting three major parameters; electron density, effective mass and plasmon damping rate. The analysis well reproduced values of electron density and mobility deduced by Hall measurement. Electron effective mass of m‖*/m0 = 0.05 (±0.01) was also obtained as the best‐fit parameter. The result agrees well with previous data obtained by other optical methods. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Hall mobilities in GaNxAs1‐x
Authors: Olea Javier , Yu Kin Man , Walukiewicz Wladek , Gonzalez‐Díaz Germán 
Published: May 2010

AbstractIn this work we report a systematic study of the electron and hole mobilities of GaNxAs1‐x alloys with different dopants (Zn, Te) and carrier concentrations (1017‐1019 cm‐3). We found a very slight reduction of the hole mobility in p‐GaNxAs1‐x compared to p‐GaAs, indicating that for small N contents (∼1.6%) the valence band is not affected by the N incorporation. In a striking contrast, incorporation of even small amounts of N leads to an abrupt reduction of the electron mobility in n‐GaNxAs1‐x. We further show that the processes that limit the mobility in GaNxAs1‐x can be explained by the band broadening and the random field scatterings. Considering these two scattering mechanisms we calculated the dependence of electron mobilities on electron concentration as well as on N composition in GaNxAs1‐x. The calculations agree reasonably well with experiment data of maximum electron mobilities with alloy composition. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The Boltzmann–Hamel equations for the optimal control of mechanical systems with nonholonomic constraints
Authors: Maruskin Jared M. , Bloch Anthony M. 
Published: May 2010

AbstractIn this paper, we generalize the Boltzmann–Hamel equations for nonholonomic mechanics to a form suited for the kinematic or dynamic optimal control of mechanical systems subject to nonholonomic constraints. In solving these equations one is able to eliminate the controls and compute the optimal trajectory from a set of coupled first‐order differential equations with boundary values. By using an appropriate choice of quasi‐velocities, one is able to reduce the required number of differential equations bymand 3mfor the kinematic and dynamic optimal control problems, respectively, wheremis the number of nonholonomic constraints. In particular we derive a set of differential equations that yields the optimal reorientation path of a free rigid body. In the special case of a sphere, we show that the optimal trajectory coincides with the cubic splines onSO(3). Copyright © 2010 John Wiley & Sons, Ltd.
Estimating channel‐forming discharge in urban watercourses
Authors: Annable W. K. , Lounder V. G. , Watson C. C. 
Published: May 2010

AbstractSeveral methods of estimating channel‐forming discharge were conducted on 12 quasi‐stable urban stream channels ranging from 9 to 99% urban land use to test their applicability in the urban condition. Bankfull stage was identified at a series of locations along each study reach and it was found that the most consistent observations of bankfull discharge occurred during flood conditions where bankfull stage was identified at the top of point bars along the convex arc of bends. The largest errors in estimation occurred at gauge stations where cross‐sectional geometry had been altered to conform to bridges or culverts rather than the channel morphology. Independent evaluations of channel forming discharge were conducted by 11 practitioners ranging from 10 years to 43 years of experience with similar findings and errors.Various methods of relating frequency return periods were evaluated using annual peak series discharge observations and continuous 15‐min systematic discharge records using partial duration series analysis. Bankfull discharge was observed to occur more than once a year in all of the urban streams studied and often averaged from 4 to 8 bankfull discharge or larger events per year. In one particular case in a single given year 18 events exceeding bankfull discharge were observed. No specific correlations were identified between frequency return periods and land use change. However, based upon the findings of this study, the applicability of employing annual series peak discharge data to evaluate bankfull frequency return in urban stream channels is highly discouraged. Copyright © 2010 John Wiley & Sons, Ltd.
ToF‐SIMS and principal component analysis: Effect of film thickness on crystal surfaces of polymers
Authors: Lau Yiu‐Ting R. , Weng Lu‐Tao , Ng Kai‐Mo , Chan Chi‐Ming 
Published: May 2010

AbstractThe effect of film thickness on the structural conformation of the surfaces of the amorphous state, edge‐on lamellae and flat‐on lamellae of a semiflexible polymer, poly(bisphenol‐A‐etheroctane), was investigated by time‐of‐flight secondary ion mass spectrometry (ToF‐SIMS) with the aid of principal component analysis (PCA). PCA results empirically indicate that a structurally regular polymer surface was obtained with the formation of the flat‐on lamellae from the amorphous state at a low degree of supercooling. A higher concentration of end group and cilium ion fragments, which are indicative of free chain ends, was observed on the edge‐on lamellar surfaces than on the amorphous and the flat‐on lamellar surfaces. This finding was attributed to the fact that the lateral surface of the edge‐on lamellae contains many growth fronts, leaving behind a large number of uncrystallized chain remnants on the surfaces. Structural disorder was facilitated on both edge‐on and flat‐on lamellar surfaces as the film thickness decreased. Hence, this PCA study offers new insights into the nonequilibrium nature of polymer crystals and the mechanism of polymer crystallization in thin and ultrathin films. Copyright © 2010 John Wiley & Sons, Ltd.
Femto‐ and attosecond electron dynamics in 5′‐Guanosine monophosphate interface as probed by resonant Auger spectroscopy
Authors: Ikeura‐Sekiguchi Hiromi , Sekiguchi Tetsuhiro 
Published: May 2010

AbstractTo help in our understanding of the electron transport properties of deoxyribonucleic acid (DNA), it is useful to study the interfacial interaction between each nucleotide building block of DNA. Electron transfer properties between phosphate groups in microcrystalline 5′‐Guanosin monophosphate (GMP) were probed using energy‐dependent resonant Auger spectroscopy. Results show that the phosphate group of GMP forms an extended state along the phosphate directions similar to the case of DNA phosphate backbones. Electron delocalization time of the phosphate groups in GMP is faster than those of DNA, as estimated using the core‐hole clock method. This suggests that interface between GMP phosphate groups would have the lowest tunneling barrier among DNA related systems. Although the π–π coupling of nucleobases is only recognized as charge‐transfer pathway in DNA and related systems, another conduction pathway through phosphate groups would be possible. Copyright © 2010 John Wiley & Sons, Ltd.
Influence of the ferroelectric polarization on the electronic structure of BaTiO3 thin films
Authors: Barrett N. , Rault J. , Krug I. , Vilquin B. , Niu G. , Gautier B. , Albertini D. , Lecoeur P. , Renault O. 
Published: May 2010

AbstractMicron scale ferroelectric (FE) domains have been written into a 20‐nm‐thick epitaxial thin film of BaTiO3 (001) [BTO(001)] on a Nb‐doped SrTiO3 substrate using a piezoforce microscope (PFM). The domain‐dependent electronic structure has been studied using fully energy‐filtered photoemission electron microscopy (PEEM) and synchrotron radiation. Shifts, induced by FE polarization, of up to 300 meV were observed in the work function of the sample. The surface is Ba‐O terminated. Polarization‐induced distortion of the electronic structure was observed in the valence band and on the Ba 3d, Ti 2p and O 1s core levels of BTO. Polarization‐dependent surface adsorption was observed. A simple electrostatic model based on net surface charge is not sufficient to explain the observed modifications in the electronic levels. Copyright © 2010 John Wiley & Sons, Ltd.
Developing ToF‐SIMS methods for investigating the degradation of plastic debris on beaches
Authors: Biesinger Mark C. , Corcoran Patricia L. , Walzak Mary Jane 
Published: May 2010

AbstractPlastic debris in the Earth's oceans and larger freshwater (FW) bodies presents a serious environmental threat to aquatic organisms. Degradation of plastic by mechanical erosion and chemical weathering is minimal in water. Once deposited on beaches, plastic fragments are exposed to UV radiation and physical processes controlled by winds, currents and waves. Recent work1 has indicated that saltwater (SW) beach plastics feature both mechanically and chemically weathered surface textures, wherein mechanically weakened fractures are the sites of granular oxidation textures. Analysis of lacustrine (FW) beach plastics is now ongoing, and shows similar textural effects of mechanical and chemical weathering.TOF‐SIMS, with its high spatial resolution and ability to detect molecular species, is ideally suited to explore chemical changes and oxidative processes occurring in these plastics. The method enables detection of low levels of absorbed species present in oxidized polymeric materials.2 TOF‐SIMS analysis is currently being conducted to investigate the oxidation process in polyethylene beach plastics from both SW (Kauai, HI, USA) and FW (Lake Huron, ON, Canada) beaches. Copyright © 2010 John Wiley & Sons, Ltd.
Development of chain‐folding of semicrystalline polymers in thin films: a combined ToF‐SIMS and PCA analysis
Authors: Lau Yiu‐Ting R. , Weng Lu‐Tao , Ng Kai‐Mo , Chan Chi‐Ming 
Published: May 2010

AbstractPoly(bisphenol‐A‐etheralkane), BA‐Cn(n, which is the number of aliphatic CH2 units, = 8 and 10), composed of rigid and flexible segments, is a semicrystalline polymer. In 50‐nm‐thick films, the polymers tend to develop flat‐on lamellae at the surfaces. Principal component analyses (PCAs) of the ion images were used to discriminate the conformation between the amorphous and flat‐on lamellar surfaces of the polymers. The changes of the surface structure were directly detected by time‐of‐flight secondary ion mass spectrometry chemical imaging when flat‐on lamellae were developed from the polymer melts. These structural changes were related to the lengths of the folded segments, which were strongly influenced by the crystallization temperature. The PCA loading analyses suggested that the length of the folded segments, which contained flexible and the rigid segments with an ether linkage, increased when the crystallization temperature decreased, suggesting the kinetic origin of polymer crystallization. Copyright © 2010 John Wiley & Sons, Ltd.
Surface and interface analysis of iodine‐doped pentacene structures for OTFTs
Authors: Jakabovič J. , Vincze A. , Kováč J. , Srnánek R. , Kováč J. , Dobročka E. , Donoval D. , Heinemeyer U. , Schreiber F. , Machovič V. , Uherek F. 
Published: May 2010

AbstractWe investigated the impact of iodine doping on structural properties of pentacene layers as a function of iodine concentration, which is controlled by the diffusion time. Furthermore, also the storing history of the samples is examined. We found that the iodine doping properties of pentacene samples strongly depend on the storing conditions (ambient atmosphere, time) before diffusion. We observed that the iodine diffusion process into pentacene layers is much faster for new recently prepared samples in contrast to old samples that were stored a few months at atmospheric ambient condition in the dark box before iodine diffusion. Copyright © 2010 John Wiley & Sons, Ltd.