bluuebunny/crossref_metadata_2025_split huggingface dataset:
Rational design of a fusion partner for membrane protein expression in E. coli
Authors: Luo Jianying , Choulet Julie , Samuelson James C. 
Published: June 2009

AbstractWe have designed a novel protein fusion partner (P8CBD) to utilize the co‐translational SRP pathway in order to target heterologous proteins to the E. coli inner membrane. SRP‐dependence was demonstrated by analyzing the membrane translocation of P8CBD‐PhoA fusion proteins in wt and SRP‐ffh77 mutant cells. We also demonstrate that the P8CBD N‐terminal fusion partner promotes over‐expression of a Thermotoga maritima polytopic membrane protein by replacement of the native signal anchor sequence. Furthermore, the yeast mitochondrial inner membrane protein Oxa1p was expressed as a P8CBD fusion and shown to function within the E. coli inner membrane. In this example, the mitochondrial targeting peptide was replaced by P8CBD. Several practical features were incorporated into the P8CBD expression system to aid in protein detection, purification, and optional in vitro processing by enterokinase. The basis of membrane protein over‐expression toxicity is discussed and solutions to this problem are presented. We anticipate that this optimized expression system will aid in the isolation and study of various recombinant forms of membrane‐associated protein.
An application of spatially autoregressive models to the study of US county mortality rates
Authors: Sparks Patrice Johnelle , Sparks Corey S. 
Published: June 2009

AbstractCounty mortality rates in the US tend to be associated with social and economic resources of counties and the unequal distribution of these resources across space. The processes that generate these social and economic inequalities are often tied to geographical location. In this paper, we present an application of spatially autoregressive models of US county mortality rates that control for the social and economic conditions that often influence mortality rates and the effects of spatial structure of counties in the US. We suggest that arguments are missing from the social science and demographic literatures to offer possible explanations for the spatial patterning of county mortality rates and ecological correlates of these rates at the county level. We find that, after controlling for spatial structure in the data, several key social variables become insignificant in the analysis. We suggest that spatial statistical models are valuable tools in the social and behavioural sciences but that the use of these methods needs to be well grounded in considerations about the spatial process inherent to the outcome studied, and the applications of these methods should not be used solely for post hoc statistical correction. Copyright © 2009 John Wiley & Sons, Ltd.
Novel red phosphor of Eu3+, Bi3+ coactivated double tungstates
Authors: Wang Zhengliang , Liang Hongbin , Wang Qin , Chen Minghong , Gong Menglian , Su Qiang 
Published: June 2009

AbstractEu3+, Bi3+ coactivated double‐tungstate phosphors were prepared by the solid‐state reaction technique, and their photoluminescent properties were investigated. No concentration quenching of Eu3+ was observed in the series samples of NaLa1–x (WO4)2:x Eu3+. With the introducing of Bi3+ions, the intensities of the excitation and emission of these phosphors were increased. The phosphor NaEu0.70(WO4)2:0.30Bi3+ showed a broadened excitation band around 400 nm and intensely red emissions under ∼400 nm light excitation, with the CIE chromaticity coordinates (x = 0.66, y = 0.34). Hence, the novel phosphor NaEu0.70(WO4)2:0.30Bi3+ may find application in the fabrication of near‐UV InGaN‐based LEDs. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Influence of addition of Al2O3 on physical, structural, acoustical and in‐vitro bioactive properties of phosphate glasses
Authors: Manupriya  , Thind K. S. , Singh K. , Sharma G. , Rajendran V. 
Published: June 2009

AbstractFour different formulations of phosphate glasses in the system P2O5–CaO–Na2O–Al2O3 were developed. The elastic moduli have been obtained using the known method at room temperature. Their physicochemical and structural evolution was analyzed during in‐vitro degradation in SBF (simulating body fluid) at 37 °C after 30 days. The results showed that the weight loss of the glass is greatly reduced with the incorporation of only 3 mol% of Al2O3 in P2O5–CaO–Na2O glass composition. Fourier transform infrared (FTIR) spectroscopy performed on glasses before and after dipping in SBF showed calcium phosphate glasses in the system P2O5–CaO–Na2O reinforced with Al2O3 offer an interesting option for slowly resorbable materials as compared to other calcium phosphate glasses with high degradation velocity. The chemical formulation of these glasses allows the synthesis of materials with a controlled solubility. However, the substitution of Al2O3 ≥ 5 mol% negatively affects the bioactivity of the P2O5–CaO–Na2O glasses. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Electron emission from nanometric apertures in CNTs‐based field emission triode structures on silicon substrates
Authors: Koohsorkhi Javad , Mohajerzadeh Shamsoddin 
Published: June 2009

AbstractIn this paper, we report a simple analytical model for carbon nanotube (CNT) based electron emitters and triode field emission devices on silicon substrates. Carbon nano‐tubes have been grown in a direct current plasma enhanced chemical vapour deposition (dc PECVD) reactor from Ni catalyst islands. CNTs are electrically isolated by a TiO2 film and a chromium layer acts as the metal gate. The effects of the surrounding gate as well as the current–voltage behavior are investigated. To verify the experimental results of this structure a theoretical model is developed, using the Fowler–Nordheim tunneling effect combined with the electrodynamics theory. With certain simplifying assumptions, we replace the complex structure of triode devices with a simple structure which arrives at a closed formulation to predict field emission properties. Field enhancement factor is an important factor that depends on the CNT shape, gate opening and the applied voltage. In our fabrication process, the gate opening diameter can be of the order of the CNT diameter. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Studies on organic light‐emitting diodes based on rubrene‐doped zinc quinolate
Authors: Saxena Kanchan , Mehta Dalip Singh , Rai Virender Kumar , Srivastava Ritu , Chauhan Gayatri , Kamalasanan M. N. , Jain V. K. 
Published: June 2009

AbstractWe report on the fabrication and performance of organic light‐emitting diodes (OLEDs) employing rubrene‐doped metal chelate namely, zinc quinolate (Znq2) as emissive layer. Different OLED architectures were carried out to improve the device performance by doping varying concentrations (by wt%) of rubrene dye into Znq2 host. Enhanced electroluminescence (EL) intensity was achieved using oxygen‐plasma‐treated indium tin oxide as anode, N,N′‐di‐1‐naphthyl‐N,N′‐diphenyl‐1,1′‐biphenyl‐4,4′diamine (α‐NPD) as hole‐transport layer, 10 weight percent rubrene‐doped Znq2 as emission layer, Znq2 as electron‐transport layer, LiF as electron‐injection layer and aluminum as cathode. It has been demonstrated that by using Znq2 as electron‐transport layer and host for dopant (rubrene) is the most suitable device structure for achieving low drive voltage and high efficiency. Electroluminescence spectra of rubrene‐doped OLED devices were also studied. The EL spectral peak was found to be shifted to 565 nm and spectral full‐width at half maximum (FWHM) of rubrene‐doped device was found to be 58 nm, while it was 95 nm in the case of a pure Znq2‐based OLED device. No further significant changes in EL spectra, such as, spectral broadening, narrowing or peak shifting were observed on changing the concentration of the rubrene dye. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Reliability aspects of SiC Schottky diodes
Authors: Holz Matthias , Hilsenbeck Jochen , Rupp Roland 
Published: June 2009

AbstractIn recent years, silicon carbide (SiC) high‐voltage power devices have gained an ever‐increasing market share. The fast development of new device concepts and technologies, e.g. for SiC Schottky diodes, has led to devices with superior switching behaviour, which renders SiC power devices especially favourable for high‐frequency applications. As of today, SiC devices enter various fields like, e.g. server power supplies, solar inverters, and drives. These applications pose quite different requirements not only on the electrical properties, but also on the long‐term reliability of the devices. In this paper, we describe in detail how Infineon's SiC Schottky diodes excel the reliability requirements. We point out how material properties, device design and packaging technology affect the overall device reliability and how they can be optimized. In addition, we describe measurement results after stress tests that go far beyond standard stress tests according to JEDEC. E.g., we show that SiC devices can safely be operated at high voltage slopes of 120 V/ns. In addition, we show that the use of high performance die attach further improves the device properties and reliability. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Lattice dynamics and thermal properties of SrHfO3 by first‐principles calculations
Authors: Murata Hidenobu , Yamamoto Tomoyuki , Moriwake Hiroki , Tanaka Isao 
Published: June 2009

AbstractFirst‐principles lattice dynamics calculations are systematically made on four polymorphs of SrHfO3. The hierarchy of the total energy at the ground state is Pm$ \bar 3 $m > I4/mcm > Cmcm > Pnma, which agrees with the sequence of iterative transitions with temperature as reported by experiments. Three structures, Pm$ \bar 3 $m, I4/mcm and Cmcm, are found to be dynamically unstable at the ground state. A soft mode of phonons appears in I4/mcm and Cmcm at the Γ‐point. The atomic displacements for the soft mode are analogous to those of the R25 mode of Pm$ \bar 3 $m, which is related to the rotation of the HfO6 octahedron. Pnma phase shows lowest energy and it is the only dynamically stable structure among the four phases. The volume expansion coefficient, bulk modulus and heat capacity are computed within quasi‐harmonic approximations using the vibrational density of states. They are compared to experimental data. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
NEXAFS studies of copper phthaloyanine on Ge(001)‐2 × 1 and Ge(111)‐c(2 × 8) surfaces
Authors: Holland B. N. , Peltekis N. , Farrelly T. , Wilks R. G. , Gavrila G. , Zahn D. R. T. , McGuinness C. , McGovern I. T. 
Published: June 2009

AbstractA comparative investigation of the molecular orientation of copper phthalocyanine on the surfaces of Ge(001)‐2 × 1 and Ge(111)‐c(2 × 8) is presented. As a first step, intrinsic NEXAFS spectra are established through a combination of the computational technique of DFT and an experiment of a well ordered monolayer film on the weakly interacting highly oriented pyrolytic graphite substrate. This reveals σ * intensity in the usual π* region, which is excluded in subsequent analysis of the orientation of molecules. At monolayer coverage the molecules lie close to parallel to the substrate, whereas in a thin film they tend towards perpendicular to the substrate. On the more weakly interacting Ge(111) surface the orientation is more extremal for both monolayer and thin film, indicating possible contributions from both disorder and an adsorption‐related extrinsic effect on Ge(001). (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Flexomagnetoelectric effect in bismuth ferrite
Authors: Zvezdin Anatoly K. , Pyatakov Alexander P. 
Published: June 2009

AbstractThere is a profound analogy between the inhomogeneous magnetoelectric effect in multiferroics and the flexoelectric effect in liquid crystals. This similarity gives rise to the flexomagnetoelectric polarization induced by spin modulation. The theoretical estimations of flexomagnetoelectric polarization agree with the value of jumps of magnetoelectric dependences (∼20 μC/m2) observed at spin cycloid suppression in a critical magnetic field of 200 kOe. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Defects in zinc doped silicon studied on base of X‐ray diffuse scattering analysis
Authors: Privezentsev Vladimir 
Published: June 2009

AbstractIn the this work are presented results of investigation of the defects in n‐Si<Zn> crystal lattices by the X‐ray diffractometry method at triplet‐crystal combination mode. Experimental n‐Si<Zn> samples were made by a high‐temperature diffusion annealing of Zn with subsequent quenching. After analysis of diffusion scattering it was established, that crystal lattice Si<Zn> contains plenty defects of micron sizes. There are revealed likewise small‐scale defects with sizes nearby 50 nm. The type of them is admittedly chaotically distributed dislocations, but part of them may be connected with spherical clusters or dislocation loops. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Preface: Phys. Status Solidi C 6/7
Authors: Nassiopoulou Androula , Canham Leigh , Sailor Michael , Schmuki Patrik 
Published: June 2009

AbstractDear reader of these proceedings,We hope you find this collection of papers interesting and useful for your research. These are the submit‐ted papers that were accepted for publication at PSST 2008, the 6th International Conference on Porous Semi‐conductor Science & Technology held at Sa Coma, Mallorca, Spain from 10–14 March 2008. A full collection of extended abstracts is also available in hardback (ISBN 978‐84‐608‐0720‐9) and via www.upv.es/psst‐2008.This biennial scientific forum focuses entirely on porous semiconductors, and as one of its traditions, has been held in varying locations across Spain since being initiated in 1998.Technical programmeThe conference was preceded by a series of short courses, given by the four conference chairs, which covered most of the current and emerging topics of this scientific field:Semiconductor electrochemistryChemical and biological sensingMedical and nutritional applicationsElectronics and micromachiningThere were then technical sessions on:Semiconductor anodizationPore initiation control and patterningSemiconductor and metal nanocompositesPhotonics and energy applicationsMesoporous titania and zinc oxideMEMS and advanced electronicsLuminescence and energy transferNanocrystal suspensions and bioimagingChemical and biological sensingManipulation of surface chemistryBiointerfaces: Proteins, cells, bacteria and virusesMedical therapeutics and treatmentsAdvanced characterizationMicrofluidics and separationsThe two evening poster sessions had over 100 contributions and were the focus of many discussions and debate.Social programmeBoth the local organizers and chairs cherish the biennial PSST friendly ambiance maintained over a dec‐ade to date. This year was no exception and the delegates were brought together socially via a mid‐week ex‐cursion to Palma de Mallorca and by a very memorable conference dinner and disco.AcknowledgementsWe would like to thank all delegates for their contributions, and once again apologize for the long time it took us as Guest Editors to complete the refereeing process. Special thanks go to our sponsors and the fantastic team of local organ‐izers led by Eugenia Matveeva. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Electronic spectrum of 2‐pyridone+: Ab initio and time‐dependent density functional calculations
Authors: Hammoutène D. , Hochlaf M. , Ciofini I. , Adamo C. 
Published: June 2009

AbstractIn a comparative study, the doublet and quartet electronic states of the 2‐pyridone+ cation are calculated using the PBE0/6‐311+G(d,p) technique and the CASSCF and MRCI(+Q) methods in connection with the cc‐pVDZ and cc‐pVTZ Dunning's basis sets. Our data show that TD‐DFT describes quite well the vertical excitation energies of these electronic states, whereas, multiconfiguration methods should be used for the investigation of the fragmentation and the dynamics of this molecular species. This is related to the change of the nature of the wavefunction of these electronic states along the corresponding reactive coordinates not accounted for by TD‐DFT methods. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2010
Obtaining positions and widths of scattering resonances from a complex multiconfigurational self‐consistent field state using the M1 method
Authors: Samanta Kousik , Yeager Danny L. 
Published: June 2009

AbstractWe present a complex multiconfigurational self‐consistent field (CMCSCF)‐based approach to investigate electron‐atom scattering resonances. It is made possible by the use of second quantization algebra adapted for biorthogonal spin orbitals, which has been applied to develop a quadratically convergent CMCSCF method. To control the convergence to the correct CMCSCF stationary point, a modified step‐length control algorithm is introduced. Convergence to a tolerance of 1.0 × 10−10 a.u. for the energy gradient is found to be typically within 10 iterations or less. A method involving the first block of the M matrix defined in the multiconfigurational spin tensor electron propagator method (MCSTEP) based on the CMCSCF reference state has been implemented to investigate 2P Be− shape resonances. The position and width of these resonances have been calculated for different complete active space choices. The wide distribution of the position and width of the resonance reported in the literature is explained by the existence of two distinct resonances which are close in energy. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2010
Cluster nature of the solvent features of single‐wall carbon nanohorns
Authors: Torrens Francisco , Castellano Gloria 
Published: June 2009

AbstractThe existence of single‐wall carbon nanotubes (SWNTs) in organic solvents, in the form of clusters, is discussed. A theory is developed based on a bundlet model for clusters, describing the distribution function of clusters by size. The phenomena have a unified explanation in the bundlet model of clusters, in accordance with which the free energy of an SWNT, involved in a cluster, is combined from two components: a volume one, proportional to the number of molecules n in a cluster, and a surface one proportional to n1/2. The bundlet model for clusters enables describing the distribution function of SWNT clusters by size. The droplet model is formally analogous to the one for fullerene clusters. From purely geometrical differences, the models predict different behaviors. Single‐wall carbon nanocones (SWNCs) of various disclinations are investigated via energetic and structural analyses. Several SWNC's terminations are studied, which are different among each other because of the type of closing structure and the arrangement of them. The SWNC packing efficiencies, and interaction‐energy parameters, are intermediate between the ones of fullerene and SWNT clusters; an in‐between behavior is expected. However, SWNC properties are calculated closer to those of fullerene and more distant from those of SWNT. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2010
Explicit solvation effects on the conventional resonance model for protonated imine, carbonyl, and thiocarbonyl compounds
Authors: Braïda Benoît , Hiberty Philippe C. 
Published: June 2009

AbstractThe conventional resonance model describes carbonyls, imines, and thiocarbonyls, as well as their protonated analogues, by a superposition of two valence bond structures. Ab initio Breathing‐Orbital Valence Bond computations on formaldehyde, formimine, and thioformaldehyde as well as their protonated forms are performed to directly quantify the weights of their valence bond structures. Following a gas phase study that showed that protonation significantly increases the weight of the carbenic form relative to the π polar‐covalent bonded form (Braida, et al., Org Lett, 2008, 10, 1951), the present work estimates the influence of a polar protic solvent, modelized by water. Solvation effects are modeled explicitly by performing VB calculations on supersystems made of the organic substrate surrounded by four water molecules. It is shown that protonation significantly increases the polarity of the CX π bond in all three cases (X = O, NH, S) in solvated phase, in line with the known acceleration of nucleophilic additions on these compounds by acidic catalysis. Moreover, solvation significantly enhances the polarity of the CX π bond in the protonated forms of formaldehyde and thioformaldehyde, but has practically no effect on the CX π bond of protonated formimine. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2010
Computational study of the molecular mechanisms of caffeine action: Caffeine complexes with adenosine receptors
Authors: Poltev V. I. , Rodríguez E. , Grokhlina T. I. , Deriabina A. , Gonzalez E. 
Published: June 2009

AbstractTo understand the molecular basis of the principal biological action of the caffeine (CAF), the molecular mechanics calculations of possible complexes between CAF and the fragments of human A1adenosine receptor were performed. The fragments were selected after considerations of the CAF molecular structure and its possible interactions, as well as after an analysis of the extensive bibliography on the structure, biological role, site‐directed mutagenesis, and the modeling of the adenosine receptors. The minimum energy configurations of these complexes were obtained using two different computer programs with different force fields. The most favorable configurations correspond to the formation of two hydrogen bonds between the CAF molecule and hydrophilic amino acid residues of the fragments of transmembrane domains of the receptor. These configurations are supposed to contribute to CAF blocking of the adenosine receptors. They will be used later for the construction of model CAF complexes with two transmembrane domains simultaneously. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2010
CASSCF/CASPT2 analysis of the fragmentation of H2 on a Pd4 cluster
Authors: Barone Giampaolo , Duca Dario , Ferrante Francesco , La Manna Gianfranco 
Published: June 2009

AbstractTwo reactive pathways are described for the dissociative adsorption of a hydrogen molecule on a Pd4 pyramidal cluster, by using DFT/B3LYP and CASSCF/CASPT2 computational methods. Because of the different spin multiplicities of the cluster in the initial and final states, the reaction proceeds through a spin multiplicity change, which occurs close to the transition states. The activation energy values are very similar when the DFT method is used, whereas the CASPT2 calculations predict that the concerted mechanism is disfavored. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2010
A theoretical study of the rotational structure of the ϵ(0,0) band of NO
Authors: Velasco A. M. , Lavín C. , Martin I. , Vega M. V. , Pitarch‐Ruiz J. , Sánchez‐Marín J. 
Published: June 2009

AbstractThis study has been focused on the ϵ(0,0) band of the nitric oxide molecule, associated with the absorption electronic transition D2Σ+←X 2Π, in the energetic vacuum ultraviolet region. A temperature of 295 K has been considered. The Molecular Quantum Defect Orbital (MQDO) methodology, with which reliable spectroscopic data have been reached in the γ(0,0), δ(0,0), and δ(1,0) bands of the same molecule, has also been used for these calculations. We hope that the present results might be of straightforward use in atmospheric and interstellar chemistry. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2010