bluuebunny/crossref_metadata_2025_split huggingface dataset:
The key Cl− ligand for metal‐to‐ligand charge transfer in mononuclear terpyridine ruthenium(II) and binuclear ruthenium(II) tetrapyridylpyrazine complexes
Authors: Yoshikawa N. , Yamabe S. , Kanehisa N. , Inoue T. , Takashima H. , Tsukahara K. 
Published: May 2011

Electronic structures of binuclear ruthenium complexes [Ru2(terpy)2(tppz)]4+ (1A) and [Ru2Cl2(L)2(tppz)]2+ {L = bpy (2A), phen (3A), and dpphen (4A)} were studied by density functional theory calculations. Abbreviations of the ligands (Ls) are bpy = 2,2′‐bipyridine, phen = 1,10‐phenanthroline, dpphen = 4,7‐diphenyl‐1,10‐phenanthroline, terpy = 2,2′:6′,2″‐terpyridine, and tppz = tetrakis(2‐pyridyl)pyrazine. Their mononuclear reference complexes [Ru(terpy)2]2+ (1B) and [RuClL(terpy)]+ {L = bpy (2B), phen (3B), and dpphen (4B)} were also examined. Geometries of these mononuclear and binuclear Ru(II) complexes were fully optimized. Their geometric parameters are in good agreement with the experimental data. The binuclear complexes were characterized by electrospray ionization mass spectrometry, UV–Vis spectroscopy, and cyclic voltammograms. Hexafluorophosphate salts of binuclear ruthenium complexes of 3A and 4A were newly prepared. The crystal structure of binuclear complex 1A(PF6)4 was also determined.Orbital interactions were analyzed to characterize the metal‐to‐ligand charge‐transfer (MLCT) states in these complexes. The Cl− ligand works to raise the orbital energy of the metal lone pair, which leads to the low MLCT state. Copyright © 2011 John Wiley & Sons, Ltd.
Effect of monomer water solubility on cationic microemulsion polymerization of three components (water, surfactant, and monomer)
Authors: Arellano Jesús , Flores Jorge , Zuluaga Fabio , Mendizábal Eduardo , Katime Issa 
Published: May 2011

AbstractHere, we present the oil/water (O/W) microemulsion polymerization in three‐component microemulsions of n‐butyl acrylate, ethyl acrylate, and methyl acrylate, monomers with similar chemical structures but different water solubilities using the cationic surfactant dodecyl trimethyl ammonium bromide. The effects of monomer water solubility, initiator type and initial monomer concentration on the polymerization kinetics were studied. Reaction rates were high with final conversions between 70 and 98% depending on the monomer and reaction conditions. The final latexes were bluish, with a particle size ranging between 20 and 50 nm and polymer with molar masses in the order of 106 g mol−1. Increasing monomer water solubility resulted in a slower reaction rate, larger particles and a lower number density of particles. A higher reaction rate, larger average particle size and higher particle number density were obtained by increasing the monomer concentration. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011
Synthesis, characterization, and rheological properties of multiarm stars with poly(glycidol) core and poly(methyl methacrylate) arms by AGET ATRP
Authors: Morell Mireia , Voit Brigitte , Ramis Xavier , Serra Àngels , Lederer Albena 
Published: May 2011

AbstractWell‐defined multiarm star block copolymers poly(glycidol)‐b‐poly(methyl methacrylate) (PGOHBr‐b‐PMMAx) with an average number of PMMA arms of 85, 55, and 45 have been prepared. The core‐first approach has been selected as the methodology using atom transfer radical polymerization (ATRP) of MMA from an activated hyperbranched poly(glycidol) as the core. These activated hyperbranched macroinitiators were prepared by esterification of hyperbranched poly(glycidol) (PGOH) with 2‐bromoisobutyryl bromide. The effect of monomer/initiator ratio, catalyst concentration, time, temperature, and solvent on the growing of the arms has been studied in detail in order to optimize the process and to diminish the radical‐radical coupling. The final products and intermediates were characterized by means of size exclusion chromatography (SEC), nuclear magnetic resonance (NMR) and Fourier transform‐infrared (FTIR) spectroscopy. The length of PMMA arms was determined by SEC after cleavage of ester bond linked to PGOH core. Glass transition temperature (Tg), thermal stability and rheological properties of the multiarm star copolymers were also studied. Finally, tapping mode atomic force microscopy (TMAFM) allowed the clear visualization of nano‐sized particles (80–200 nm) corresponding to individual star molecules. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011
Synthesis of pyrene end‐capped A6 dendrimer and star polymer with phosphazene core via “click chemistry”
Authors: Gorur Mesut , Yilmaz Faruk , Kilic Adem , Sahin Zeynep M. , Demirci Ali 
Published: May 2011

AbstractNovel hexa‐armed and pyrene (Pyr) end‐capped phosphazene dendrimer [N3P3‐(Pyr)6] and star polymer with poly(ε‐caprolactone) (PCL) arms [N3P3‐(PCL‐Pyr)6] were prepared via two series of reactions. In these series, core‐first approach was used starting from a hexa‐hydroxy functional phosphazene derivative (N3P3‐(OH)6). It was used as an initiator in the ring‐opening polymerization of ε‐caprolactone to prepare a hexa‐armed PCL star polymer (N3P3‐(PCL‐OH)6). Hydroxyl functionalities of N3P3‐(OH)6 and N3P3‐(PCL‐OH)6 were then successfully converted into bromide and azide, in turn. Further end‐group modifications of azide functional dendrimer precursor (N3P3‐(N3)6) and star polymer (N3P3‐(PCL‐N3)6) were achieved quantitatively via the Cu(I) catalyzed click reaction between azide functional groups and 1‐ethynyl pyrene in the final step. Moreover, the pyrene end‐capped phosphazene dendrimer and star polymer were used in noncovalent functionalization of multiwalled carbon nanotubes. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011
Influence of dc Pulsed Atmospheric Pressure Plasma Jet Processing Conditions on Polymer Activation
Authors: Dowling Denis P. , O'Neill Feidhlim T. , Langlais Simon J. , Law Victor J. 
Published: May 2011

AbstractPlasma treatments are widely used to activate polymer surfaces prior to adhesive bonding. This study investigates the influence of plasma treatment conditions on the surface activation of a range of polymers using the PlasmaTreat (Open Air) system. In this study the effect of dc pulse plasma cycle time, compressed air flow rate and the plasma jet nozzle to substrate distance on the plasma discharge was examined. The influence that the dc pulse plasma cycle time parameter has on the activation of polypropylene, polystyrene and polycarbonate was also investigated. The level of polymer surface activation was evaluated based on the change in water contact angle after plasma treatment. The polymer surface properties were also monitored using AFM and XPS measurements. The heating effect of the plasma was monitored using both infrared thermographic camera and thermocouple measurements. Plasma diagnostics measurements were obtained using the photo‐diode and optical emission spectroscopy techniques. From this study it was concluded that for the PlasmaTreat system the level of plasma activation was closely correlated with the dc pulsed plasma cycle time, which is a measure of the plasma intensity. For example, the more intense plasma obtained with shorter cycle times gave higher levels of polymer activation. The optimized pulsed plasma cycle times were found to be specific for a given polymer type and related to their thermal properties. The pulsed cycle times were also found to correlate with both the substrate and plasma gas temperatures. magnified image
The role of Pax2 in mouse prostate development
Authors: Xu Ben , Hariharan Arun , Rakshit Sabita , Dressler Gregory R. , Wellik Deneen M. 
Published: May 2011

AbstractBACKGROUNDLoss‐of‐function of Pax2 results in severe defects of the male reproductive system, and Pax2 expression is detected in mouse prostate lobes and human prostatic cancers. However, the role for Pax2 in prostate development remains poorly understood.METHODSThe expression of Pax2 was examined by in situ hybridization at various developmental stages. Urogenital sinuses were dissected out at E18.5 from mouse Pax2 mutants and controls, cultured in vitro or grafted under the renal capsule of CD1 nude mice. The expression of prostate developmental regulatory factors was analyzed by semi‐quantitative real‐time PCR or immuohistochemistry.RESULTSPax2 is expressed in the epithelial cells of prostate buds. Loss‐of‐function of Pax2 does not affect the initiation of prostatic buds, but in vitro culture assays show that the prostates of Pax2 mutants are hypomorphic and branching is severely disrupted compared to controls. RT‐PCR data from Pax2 mutant prostates demonstrate increased expression levels of dorsolateral prostate marker MSMB and ventral prostate marker SBP and dramatically reduced expression levels of anterior prostate marker TGM4.CONCLUSIONSPax2 is essential for mouse prostate development and regulates prostatic ductal growth, branching, and lobe‐specific identity. These findings are important for understanding the molecular regulatory mechanisms in prostate development. Prostate 72:217–224, 2012. © 2011 Wiley Periodicals, Inc.
Assessment of resistance risk in Spodoptera exigua (Hübner) (Lepidoptera: Noctuidae) to chlorantraniliprole
Authors: Lai Tiancai , Su Jianya 
Published: May 2011

AbstractBACKGROUND: Beet armyworm, Spodoptera exigua (Hübner) (Lepidoptera: Noctuidae), is a major pest of numerous cultivated crops. Chlorantraniliprole, the first commercialised ryanodine receptor insecticide from the anthranilic diamide class, has exceptional insecticidal activity on a range of lepidopteran pests. The aim of this study was to assess the resistance of S. exigua to chlorantraniliprole in the laboratory.RESULTS: A field‐collected population of S. exigua was selected after repeated exposure to chlorantraniliprole to determine the risk of resistance evolution. After 22 generations of selection, there was a 12.0‐fold increase in LC50. The realised heritability (h2) of resistance was estimated as 0.1082 by using threshold trait analysis. The projected rate of resistance evolution indicated that, if h2 = 0.1082 and 70% of the population was killed at each generation, then a tenfold increase in LC50 would be expected in 21.7 generations for chlorantraniliprole.CONCLUSION: These results show that the risk of resistance development to chlorantraniliprole exists in S. exigua after continuous application. Copyright © 2011 Society of Chemical Industry
The use of combined medications in the treatment of type 2 diabetes
Authors: Bailey Cliff , Wallymahmed Maureen , Brice Richard 
Published: May 2011

AbstractDiabetes is a complex disease and patients often require multiple therapies to control the condition. For some patients, the prospect of taking several different drugs can be daunting, especially if they are already taking medications for other conditions. This Expert Panel Discussion considers which patients could benefit from taking drugs in a combined formulation, at what stage combined formulations should be used and what combined formulations are available. Copyright © 2011 Wiley Interface Ltd
The current status of ultraviolet laser diodes
Authors: Yoshida Harumasa , Kuwabara Masakazu , Yamashita Yoji , Uchiyama Kazuya , Kan Hirofumi 
Published: May 2011

AbstractWe report on nitride laser diode lasing at short ultraviolet wavelengths. We first present room temperature operations of GaN/AlGaN multiple‐quantum‐well (MQW) laser diodes under pulsed current mode. Then we report on the results of thorough investigation of the device characteristics. The optical and temperature characteristics as well as the carrier recombination of the devices have been investigated. We lastly present the first demonstration of indium‐free nitride laser diode. The laser operation of the AlGaN MQW laser diodes open the door to laser operation at shorter ultraviolet wavelengths.
GaGdN/AlGaN multiple quantum disks grown by RF‐plasma‐assisted molecular‐beam epitaxy
Authors: Tambo H. , Hasegawa S. , Uenaka M. , Zhou Y. K. , Emura S. , Asahi H. 
Published: May 2011

AbstractIII–V‐based diluted magnetic semiconductor (DMS) GaGdN/AlGaN multiple quantum disks (MQDisks) were fabricated on Si (001) substrates with native silicon oxides by RF‐plasma‐assisted molecular‐beam epitaxy (RF‐MBE). It was found that the degree of the c‐axis orientation of GaGdN/AlGaN MQDisks and the Ga atomic configuration around Gd atom were improved due to the growth of AlGaN disks, comparing with the GaGdN nanorods grown without AlGaN disks. Additionally, GaGdN/AlGaN MQDisks showed larger saturation magnetisation than that of the GaGdN nanorods. With increasing the height of AlGaN disk, saturation magnetisation was increased.
Dielectric function of Al‐rich AlInN in the range 1–18 eV
Authors: Sakalauskas E. , Behmenburg H. , Schley P. , Gobsch G. , Giesen C. , Kalisch H. , Jansen R. H. , Heuken M. , Goldhahn R. 
Published: May 2011

AbstractThe ordinary dielectric function (DF) is presented for high quality Al‐rich Al1−xInxN alloy films pseudomorphically grown on GaN in the photon energy range 1–18 eV determined by spectroscopic ellipsometry at room temperature (synchrotron radiation – BESSY II). The (0001)‐oriented layers with In content of 14.3 and 15.4% were grown by metal‐organic vapour phase epitaxy on thick GaN buffers with sapphire substrates. The sharp onset of the imaginary part of the DF defines the direct absorption edge. In previous studies the DF of Al‐rich AlInN were investigated in the photon energy range 1–10 eV, and three high‐energy critical points (CPs) of the band structure (Van Hove singularities) were observed. The current study was performed in the extended photon energy range 10–18 eV and three CPs of the band structure at ∼10.6, ∼12.5 and ∼14.2 eV were detected. XRD measurements revealed the pseudomorphic growth of AlInN films and yielded the composition. Finally, the band gap value of 4.68 eV and high‐frequency dielectric constant value of 4.55 were evaluated for sample with 15.4% In content.
Growth of high‐quality InSb layer on (001) Si substrate with an initial intermediate‐layer of InAs quantum dots
Authors: Lim J. Y. , Song J. D. , Choi W. J. , Ahn J. P. , Yang H. S. 
Published: May 2011

AbstractIn this study, we have attempted a growth of InSb film on the cost‐effective, (001)‐Si substrate inserting a thin intermediate‐layer of InAs quantum dots (QDs) at the InSb/Si interface. Analysis of the interface region using transmission electron microscopy reveals that, during the subsequent InSb‐growth process, InAs QDs have disappeared leaving instead a thin interlayer of InAs. The resulting 2.8‐µm‐thick InSb film on (001) Si is found to have an electron mobility of 40 907 cm2/Vs at 300 K, which turned out to be the highest value for InSb with comparable thickness grown on Si substrate.
Optical and structural properties of silicon‐rich silicon oxide films: Comparison of ion implantation and molecular beam deposition methods
Authors: Nikitin Timur , Aitola Kerttu , Novikov Sergei , Räsänen Markku , Velagapudi Rama , Sainio Jani , Lahtinen Jouko , Mizohata Kenichiro , Ahlgren Tommy , Khriachtchev Leonid 
Published: May 2011

AbstractWe compare optical and structural properties of silicon‐rich silicon oxide (SiOx, x ∼ 1.8) films obtained by ion implantation and molecular beam deposition (MBD). Before annealing, amorphous clusters (≥2 nm) are present in the MBD samples whereas these are absent for ion implantation, and the absorption at 488 nm is much stronger for MBD. Upon annealing, the absorption coefficient increases for the implanted material but the opposite change occurs for MBD. For both preparation methods, annealing at ∼1100 °C produces silicon nanocrystals (Si‐nc) and enhances the 1.5‐eV photoluminescence (PL) whereas annealing at 1200 °C decreases the PL, especially for the implanted sample. The Si–SiO2 phase separation is not complete even after annealing at 1200 °C.
Magnetization reversal in Co‐base nanowire arrays
Authors: Vázquez Manuel , Vivas Laura G. 
Published: May 2011

AbstractThe magnetic behaviour of ordered arrays of magnetic nanowires is controlled by the combined action of anisotropy energy terms determined by geometrical shape, crystalline structure and magnetostriction, as well as by the magnetostatic interactions among them. A number of works have been reported on the role of magnetostatic interaction in arrays of nanowires, sometimes focusing on nanowires with vanishing crystalline and magnetostrictive energy terms. Here, in turn we are interested in Co‐base nanowires whose magnetocrystalline anisotropy plays a very important role. Arrays of Co‐base nanowires offer novel, sometimes unexpected behaviour that is not fully understood. Such results are connected to their magnetocrystalline anisotropy, and to their complex magnetization reversal mode. Arrays of Co and Co‐base nanowires have been fabricated by template‐assisted method, by electroplating into highly ordered self‐assembled pores of nanoporous alumina membranes. Their hcp or fcc crystal structure is confirmed to depend on length of nanowires as well as on the presence of selected elements in the composition. The magnetic behaviour of these arrays has been experimentally investigated as a function of (i) geometry (e.g. diameter and, particularly short length) and (ii) composition (e.g. adding Ni or Pd). A complementary study on its temperature dependence reveals the nature of the dominant anisotropy, while the angular dependence of hysteresis loops (e.g. coercivity and remanence) enables a deeper analysis of the magnetization reversal process. Micromagnetic reversal modes are reviewed and modelling and simulations procedures introduced. Complex rotational mechanisms are concluded to be responsible for the reversal process following micromagnetic modes distinct from those pure classically established.magnified image
SEM image of an array of Co‐base nanowires.
Study of edge termination structures for high power GaN Schottky diodes
Authors: Sundaramoorthy Vinoth Kumar , Nistor Iulian 
Published: May 2011

AbstractDifferent structures of field plate termination were analysed by numerical simulation to enhance the breakdown voltage of quasi‐vertical GaN Schottky diodes. A bevel shaped field plate achieved a maximum breakdown voltage of 1990 V for 1.5 µm thick oxide layer with 18 µm bevel width. Maximum breakdown voltage was achieved when the bevel angle is 5°. A fabrication friendly 4 step field plate structure achieved a breakdown voltage of 1650 V and 1970 V respectively, with oxide and silicon nitride passivation. The width and thickness of the first step were the most influential factors in deciding the maximum breakdown voltage. A multi‐step field plate structure, which is an emulation of bevel structure, achieved a breakdown voltage of 1600 V and 1850 V with oxide and silicon nitride passivation layers, respectively. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Theoretical simulations of radiative recombination time in polar InGaN quantum wells
Authors: Gladysiewicz M. , Kudrawiec R. , Syperek M. , Misiewicz J. , Siekacz M. , Cywinski G. , Skierbiszewski C. , Suski T. 
Published: May 2011

AbstractThe radiative recombination time (τr) was calculated for inhomogeneous polar InGaN QWs emitting in the green spectral range. These calculations were performed in the framework of a model where the τr is inversely proportional to the electron‐hole overlap integral. In order to simulate inhomogeneities in this model, it was assumed that the QW width, barrier widths and indium concentration vary with a Gaussian distribution where the nominal QW width, barrier widths and indium concentration correspond to the mean value in this distribution and their fluctuations correspond to the deviation from the main value. The τr was calculated for five thousands of randomly generated InGaN QWs and next the spectral map of PL decay was generated for the calculated τr which correspond to various QW regions. The obtained maps were compared with the measured maps of PL decay for InGaN QWs emitting in the green spectral range. It has been clearly shown that QW inhomogenities (i.e., QW width fluctuations and indium concentration fluctuations) lead to a spectral dispersion of the τr and the non‐exponential behavior of PL decay curves. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Optimization of recessed ohmic contacts for AlGaN/AlN/GaN heterostructures using C(V) characterization of MSHM structures
Authors: Fagerlind Martin , Rorsman Niklas 
Published: May 2011

AbstractRecess etching is used to reduce the resistance of ohmic contacts to an AlGaN/AlN/GaN heterostructure. The minimization of the resistance relies on exact etching of the barrier. For this purpose C(V) measurements of the etched contacts, before annealing, are used to characterize the effect of the recess etch. Using the C(V) measurements a Cl2/Ar based ICP/RIE etch recipe with a stabilized etch rate of approximately 3 Å/s is developed. By utilizing the recess etch the contact resistivity is reduced from the non etched 0.9 Ω · mm to 0.3 Ω · mm when approximately 2 nm remains of the barriers, while maintaining a low sheet resistance. The C(V) measurements make it possible to monitor sheet carrier density vs. etch depth. Furthermore, the C(V) measurement gives large‐area average values that is not easily obtained with AFM measurements (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Erbium doped silica‐hafnia glass ceramic waveguides
Authors: Berneschi Simone , Chiappini Andrea , Ferrari Maurizio , Pelli Stefano , Righini Giancarlo C. 
Published: May 2011

AbstractAim of this paper is to present a short review of the main results obtained in our laboratories on Er3+‐doped SiO2: HfO2 glass ceramic waveguides fabricated by sol–gel route and dip–coating technique, employing either top–down or bottom–up approach (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Light induced 2D chiral structure on the surface of azo‐polymer films
Authors: Kandjani Sohrab Ahmadi , Barille Regis , Nunzi Jean‐Michel , Kheradmand Reza , Tajalli H. 
Published: May 2011

AbstractIn this experimental work, we present a simple method for fabrication of 2D chiral structure on the surface of an azo‐polymer film. It has been shown that illuminating of an azo‐polymer film with a single uniform laser beam can create the surface relief pattern on the surface of the film. For different state of polarization different structures are obtained. Under ∼33° incidence angle and for 45° polarization direction, the formed structure is asymmetric, and it does not have a symmetry axis in the 2D plane. The AFM images of these patterns are not superimposable with their mirror images if we rotate the images in their planes. On the other hand, the mirror images of Fourier Transform of AFM images also are not coinciding with Fourier Transform of AFM images. Consequently, this structure is a 2D chiral structure. These patterns are shown the capability to rotate the polarization state of diffracted light in the transmission regime. The changes in the polarization state of light associate with the chirality of sample. This is a one‐step very simple and reversible method to fabricate 2D chiral systems (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)