bluuebunny/crossref_metadata_2025_split huggingface dataset:
Benchmark study on glyphosate‐resistant cropping systems in the United States. Part 5: Effects of glyphosate‐based weed management programs on farm‐level profitability
Authors: Weirich Jason W , Shaw David R , Owen Micheal DK , Dixon Philip M , Weller Stephen C , Young Bryan G , Wilson Robert G , Jordan David L 
Published: May 2011

AbstractBACKGROUND: Glyphosate‐resistant (GR) crops have changed the way growers manage weeds and implement control strategies. Since the introduction of GR crops, growers in many instances have relied on glyphosate almost exclusively to control a broad spectrum of weeds. This overreliance on glyphosate has resulted in the evolution of glyphosate resistance in some weed species. Growers and scientists are concerned about the sustainability of GR crops and glyphosate. When a grower is making decisions about weed control strategies, economic costs and benefits of the program are primary criteria for selection and implementation. Studies across six states were initiated in 2006 to compare the economics of using a weed resistance best management practice (BMP) system with a grower's standard production system.RESULTS: Resistance BMP systems recommended by university scientists were more costly but provided similar yields and economic returns. Rotation of GR crops resulted in a higher net return (maize and soybean) compared with continuous GR crop (cotton or soybean) or rotating a GR crop with a non‐GR crop (maize).CONCLUSION: Growers can implement weed resistance BMP systems with the confidence that their net returns will be equivalent in the short run, and, in the long term, resistance BMP systems will prevent or delay the evolution of GR weeds in their fields, resulting in substantial savings. Copyright © 2011 Society of Chemical Industry
Gene amplification and insecticide resistance
Authors: Bass Chris , Field Linda M 
Published: May 2011

AbstractPesticide resistance in arthropods has been shown to evolve by two main mechanisms, the enhanced production of metabolic enzymes, which bind to and/or detoxify the pesticide, and mutation of the target protein, which makes it less sensitive to the pesticide. One route that leads to enhanced metabolism is the duplication or amplification of the structural gene(s) encoding the detoxifying enzyme, and this has now been described for the three main families (esterases, glutathione S‐transferases and cytochrome P450 monooxygenases) implicated in resistance. More recently, a direct or indirect role for gene duplication or amplification has been described for target‐site resistance in several arthropod species. This mini‐review summarises the involvement of gene duplication/amplification in the insecticide/acaricide resistance of insect and mite pests and highlights recent developments in this area in relation to P450‐mediated and target‐site resistance. Copyright © 2011 Society of Chemical Industry
Cross‐resistance of horseweed (Conyza canadensis) populations with three different ALS mutations
Authors: Zheng Danman , Kruger Greg R , Singh Sukhvinder , Davis Vince M , Tranel Patrick J , Weller Stephen C , Johnson William G 
Published: May 2011

AbstractBACKGROUND: Horseweed is a weed commonly found in agronomic crops, waste areas and roadsides. Resistance to ALS‐inhibiting herbicides in horseweed was first reported in 1993 in a population from Israel. Resistance to ALS‐inhibiting herbicides in horseweed is now widespread, but, as of now, the resistance mechanism has not been reported.RESULTS: Two of three populations evaluated (P116 and P13) were found to be uniform for resistance (>98% of individuals survived 8.8 g AI ha−1 of cloransulam), whereas a third population, P525, contained about 85% resistant individuals. Cross‐resistance to cloransulam, chlorimuron, imazethapyr and bispyribac was observed in the P116 population. P525 and P13 were both sensitive to imazethapyr but resistant to chlorimuron, imazethapyr and bispyribac. Enzyme activity assays indicated that resistance in P13 was due to an altered target site. Southern blot analysis indicated that the ALS target site is encoded by a single copy gene. Overlapping ALS gene regions were amplified and sequenced from each population. Amino acid substitutions of Ser for Pro at position 197 (P197S) was detected from P13, Ala for Pro (P197A) was identified from P525 and substitution of Glu for Asp (D376E) at position 376 was found in P116. Molecular markers were developed to differentiate between wild‐type and resistant codons at positions 197 and 376 of horseweed ALS.CONCLUSION: Resistance to ALS‐inhibiting herbicides in horseweed is conferred by target‐site mutations that have also been identified in other weed species. Identification of the mutations within horseweed ALS gene sequence enables molecular assays for rapid detection and resistance diagnosis. Copyright © 2011 Society of Chemical Industry
Ultrathin metal oxidation for vacuum monitoring device applications
Authors: Mäder Sebastian , Haas Thomas , Kunze Ulrich , Doll Theodor 
Published: May 2011

AbstractThe oxide growth on thin metal films at room temperature has been investigated in terms of resistance change during oxidation. These data have been interpreted using the extended Cabrera–Mott theory of oxidation by Boggio. The resulting oxide thickness as well as the oxidation kinetics was found to depend on pressure. According to this dependence, oxidation of ultrathin metal films can be applied for monitoring the vacuum quality inside an evacuated environment. The performance of aluminum and copper sensing layers are compared with respect to sensor lifetime and response. Furthermore, the theoretically evaluated and resistively measured oxide thicknesses are verified by TEM studies.
Simple way of fabrication of Epoxy Novolak Resin optical waveguides on silicon substrate
Authors: Prajzler Vaclav , Lyutakov Oleksiy , Huttel Ivan , Barna Jiri , Spirkova Jarmila , Nekvindova Palva , Jerabek Vitezslav 
Published: May 2011

AbstractIn this paper we report about design, fabrication and properties of the polymer optical waveguides deposited on silica‐on‐silicon substrate. The design of the waveguides is based on a concept that geometric dimensions of the single mode polymer waveguide are determined by geometrical parameters of the silica layer. The design of the waveguides was schemed for 650 nm, 850 nm, 1310 nm and 1550 nm wavelength. The design of the presented planar waveguides was realized on the bases of modified dispersion equation while the ridge waveguides design was proposed following the Fischbeck concept. Both designs were refined applying RSoft software using beam propagation method. Proposed shapes of the waveguides were etched by standard photolithography process into the silica layers and polymer waveguide layers were subsequently deposited into the treated substrate by spin coating. Epoxy Novolak Resin was used as the waveguide core material and polymethylmethacrylate was used as a cover protection layer. Propagation optical loss measurements were done by using the cut‐back method. The best samples had optical losses lower than 1.5 dB/cm at 650 nm and 0.5 dB/cm at 1310 nm (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Detailed study of flat bands appearing in metallic photonic crystals
Authors: Vala Ali Soltani , Sedghi Aliasghar , Hosseini Naser , Kalafi Manouchehr 
Published: May 2011

AbstractIt has been difficult to compute the band structures of metallic photonic crystals for H‐polarization. The existence of surface plasmon modes is the major reason for difficulty due to the localized nature of these modes. In this study, by virtue of the efficiency of the newly developed Dirichlet‐to‐Neumann map method, we are able to investigate the details of the flat bands in a two dimensional square lattice with metallic cylinders. We have obtained fine band structure for H polarization around the flat band region which has not been reported to the best of our knowledge. Our numerical results show that for the frequency around the surface plasmon, the modes are highly localized at the interface of the cylindrical metallic rods and air background and also by approaching the modes to the surface plasmon frequency the localization length decreases and the number of field's nodes increases considerably. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Polarization of optical spectra in transparent conductive oxide β‐Ga2O3
Authors: Yamaga Mitsuo , Ishikawa Tatsuya , Yoshida Masashi , Hasegawa Takamasa , Villora Encarnacion G. , Shimamura Kiyoshi 
Published: May 2011

Abstractβ‐Ga2O3 single crystals have the band gap energy of 4.8 eV. Luminescence spectra in β‐Ga2O3 crystals excited above the band gap energy consist of UV and blue/green broad bands. Polarization of the optical absorption and luminescence spectra and decay curves of the luminescence observed in the temperature range from 14 to 300 K can identify the luminescent centres. The UV luminescent centre with a lifetime of 1.5 μs is assigned as self‐trapped exciton, consisting of self‐trapped hole in the form of GaO4 tetrahedral complex and bound electron. As the decay curves of the blue/green luminescence bands fit a power function of t‐n (n∼0.8), the luminescence occurs through recombination of donors and acceptors in the crystal. The donor is coincident with a conduction electron trapped at single or coupled oxygen vacancies in the crystal estimated from electron‐spin resonance (ESR) (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Electron injection into hole‐transporting layer from emitting layer in organic light emitting diodes
Authors: Tsuboi Taiju , Kishimoto Tadahi , Wako Kazuhiro , Matsuda Kuniharu , Iguchi Hirofumi 
Published: May 2011

AbstractOptical and electrical characteristics of organic light emitting diode devices with emitting layer of N,N′‐di(naphthalene‐1‐yl)‐N,N′‐diphenyl‐benzidine (NPB) doped with 0.2, 0.5, and 1.0% tris[1‐phenylisoquinolinato‐C2, N] iridium [Ir(piq)3] are presented. Tris(8‐hydroxyquinoline) aluminum (Alq3) and NPB were used as electron and hole transport layers, respectively. Emissions from Ir(piq)3 dopant and Alq3 have been observed in all the devices. No emission from NPB host was observed even in device with 0.2% dopant concentration. This is understood by the high HOMO gap (0.8 eV) between NPB and Alq3 and by the very small HOMO gap (0.1 eV) between Ir(piq)3 and Alq3, which do not lead to injection of electrons from Alq3 electron transport layer into NPB host in emitting layer but lead to direct injection of electrons from Alq3 into Ir(piq)3. It was found that the driving voltage, external quantum efficiency, and luminous efficiency increase with increasing dopant concentration, but power efficiency decrease. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Light‐sensitive organic recording media for 3D optical memory
Authors: Barachevsky V. A. , Krayushkin M. M. , Kyiko V. V. , Grebennikov E. P. 
Published: May 2011

AbstractThis paper presents own results in the field of organic recording media for bitwise working (WERM) and archival (WORM) optical memory. For the development of recording media for bitwise WERM optical memory thermally irreversible photochromic compounds from diarylethene, fulgimide classes manifesting reversible photoinduced valence are used. For making WORM optical memory chromons which form fluorescent products from nonluminescent compounds during irreversible photochemical reaction under laser UV irradiation are suggested. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Synthesis of poly(3, 4 ethylenedioxythiophene) nano structure using reverse microemulsion polymerization
Authors: Siju C. R. , Narasimha Rao K. , Ganesan R. , Gopal E. S. R. , Sindhu S. 
Published: May 2011

AbstractWe have synthesized Poly (3,4 ethylenedioxythiophene) (PEDOT) nanostructured powder through a hexane/water reverse microemulsion system using sodium bis(2‐ethylhexyl) sulfosuccinate (AOT) cylindrical micelles as the template and ferric chloride (FeCl3) as the oxidant. Infrared spectroscopic study revealed that the polymerization of ethylenedioxythiophene leads to formation of the polymer PEDOT. The morphology of particles were studied using scanning electron microscopy (SEM) which showed nanometer sized agglomerates. The electrical conductivity of the nanopowder pellets was ∼15 S/cm. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Transport and recombination of photo‐carriers under potential fluctuation in TiOx films prepared by rf magnetron sputtering method
Authors: Sakaguchi Koichi , Shimakawa K. , Hatanaka Y. 
Published: May 2011

AbstractResidual long‐term decays of photocurrent after stopping the irradiation of UV light have been reported in titanium oxide films. Excited electrons recombine with holes through the various routs. The photocurrent decay exhibits a stretched exponential form. It is shown in the case of argon environment that the recombination is dominated by the dispersive diffusion process of electrons. In the mixture of argon and oxygen gas environment, oxygens reacting with electrons near the surface dominate recombination processes. Origin of stretched‐exponential dynamics is discussed (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Investigations of the complex impedance of photovoltaic cells under illumination
Authors: Kancsar Erika , Drapalik Markus , Schmid Julian , Schlosser Viktor 
Published: May 2011

AbstractThe low pass characteristic of a photovoltaic device in the power converting voltage range was investigated by impedance spectroscopy and signal response measurements. For a c‐Si solar cell it was found that the bandwidth varies with bias voltage, illumination intensity and circuit termination. At low intensities or voltages below +0.15 V the bandwidth becomes less than 100 Hz when the cell was terminated with a high resistive load. As a consequence reliable data acquisition of the open circuit voltage transient for a fast intensity variation (≥100 mWcm–2/s) is limited to voltages above +0.35 V. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
An effective sensitivity analysis methodology for the reliability‐based structural optimization design to high temperature components
Authors: Zheng Mianbin , Chen Guohua 
Published: May 2011

AbstractMost of physical parameters of high temperature components are usually correlated with the temperature parameter, which makes the reliability‐based structural optimization design more complicated. So far, few efficient sensitivity analysis methods adapted to highly nonlinear performance function with correlated non‐normal variables have been invented. An effective simulation approach is presented to perform reliability sensitivity analysis with the aid of Cholesky factorization and curve fitting. Moreover, in order to improve the programming and computational efficiency, the mixed programming technique of Visual Basic and MATLAB was employed to develop a reliability sensitivity analysis program. The numerical case shows that the results are consistent with those from other traditional methods, and the engineering cases indicate that the proposed method can be effectively used in highly nonlinear function with correlated non‐normal parameters. Meanwhile, the results also demonstrate that the correlation coefficient parameter of high temperature components is very important in the reliability‐based structural optimization design; hence, this parameter should be fully taken into consideration to ensure that the analysis results are accurate and reasonable. Copyright © 2011 John Wiley & Sons, Ltd.
Various atomic charge calculation schemes of CoMFA on HIF‐1 inhibitors of moracin analogs
Authors: Madhavan Thirumurthy , Gadhe Changdev G. , Kothandan Gugan , Lee Kyeong , Cho Seung Joo 
Published: May 2011

AbstractSelection of appropriate partial charges in a molecule is crucial to derive good quantitative structure–activity relationship models. In this work, several partial atomic charges were assigned and tested in a comparative molecular field analysis (CoMFA) models. Many CoMFA models were generated for a series of hypoxia inducible factor 1 (HIF‐1) inhibitors using various partial atomic charges including charge equalization, Mülliken population analysis (MPA), natural population analysis, and electrostatic potential (ESP)‐derived charges. These atomic charges were investigated at various theoretical levels such as empirical, semiempirical, Hartree–Fock (HF), and density functional theory (DFT). Among them, Merz‐Singh‐Kollman (MK) ESP‐derived charges at the level of HF/6‐31G* gave the highest predictive q2 with experimental pIC50 values. With this charge scheme, a detailed analysis of CoMFA model was performed to understand the electrostatic interactions between ligand and receptor. More elaborate charge calculation schemes such as HF and DFT correlated more strongly with activity than empirical or semiempirical schemes. The choice of optimization methods was important. As geometries were fully optimized at the given levels of theory, the aligned structures were different. They differed considerably, especially for the flexible parts. This was likely the source of the substantial variation of q2 values, even when the same steric factor was considered without electrostatic parameters. ESP‐derived charges were most appropriate to describe CoMFA electrostatic interactions among MPA, NBA, and ESP charges. Overall q2 values vary considerably (0.8–0.5) depending on the charge schemes applied. The results demonstrate the need to consider more appropriate atomic charges rather than default CoMFA charges. © 2011 Wiley Periodicals, Inc. Int J Quantum Chem, 2012
Analytical arbitrary ℓ‐wave solutions of the manning–rosen potential in the tridiagonalization program
Authors: Zhang Min‐Cang , Huang‐Fu Guo‐Qing 
Published: May 2011

AbstractBy working in a complete square integrable basis that carries a tridiagonal matrix representation of the wave operator, the arbitrary ℓ‐wave solutions of the Schrödinger equation for the Manning–Rosen potential is investigated with an approximation of centrifugal term. The resulting three‐term recursion relation for the expansion coefficients of the wavefunction is presented. The bound‐state wavefunctions are expressed in terms of the Jocobi polynomial, and the discrete spectrum of the bound states is obtained by diagonalization of the recursion relation. © 2011 Wiley Periodicals, Inc. Int J Quantum Chem, 2012
Molecular dynamics study of aggregation of amyloidogenic peptides in explicit water
Authors: Magliano A. , Anselmi M. , Di Nola A. 
Published: May 2011

AbstractThe presence of amyloid fibrils is associated with a number of degenerative and serious human diseases. Nonetheless, the process of fibrillogenesis is still poorly understood. In this study, we present the results of a molecular dynamics investigation into the self‐aggregation of the amyloidogenic peptide FLVHSS, a six‐residue peptide belonging to the sequence of human islet amyloid polypeptide (hIAPP), capable of self‐association to form amyloid‐like fibrils. The simulations were performed at T = 300 K, using multiple replicas of FLVHSS monomer with random initial spatial distribution and orientation, in explicit water, set in a confined space volume (simulation box). Different simulations were carried out by varying initial atomic coordinates or initial atomic velocities and simulation box size. The formation of a unique aggregate (cluster) was observed within few nanoseconds from the beginning of all simulations. Structural analysis of the clusters clearly showed an elongated scalene ellipsoidal shape and a preferential parallel alignment of the peptides, roughly perpendicular to the main axis of the cluster and in extended conformation. The spatial arrangement of peptides in the simulated clusters appears to be similar to the spatial disposition of molecules in amyloid fibrils. An elongated scalene ellipsoidal shape was observed also in the final aggregate of the cluster growth simulation we also reported herein, indicating a tendency of cluster to grow along its major geometrical axis. © 2011 Wiley Periodicals, Inc. Int J Quantum Chem 112:1844–1851, 2012
Targeted Cell–Cell Interactions by DNA Nanoscaffold‐Templated Multivalent Bispecific Aptamers
Authors: Liu Xiaowei , Yan Hao , Liu Yan , Chang Yung 
Published: May 2011

AbstractCell–cell interactions are essential for multicellular organisms, playing important roles in their development, function, and immunity. Herein a bottom‐up strategy to construct self‐assembled DNA nanostructures is reported, consisting of multivalent, bispecific, cell‐targeting aptamers to specifically induce cell–cell interactions. Various DNA nanoscaffolds are rationally designed to assemble aptamers with different valencies and flexibilities, and their cellular binding capabilities are tested. Multivalent aptamers, assembled on more rigid scaffolds, display higher binding activities. Further, multivalent bispecific aptamer fusion molecules are constructed based on this configuration, and successfully link two types of cells. Using cell‐targeting aptamers, the presented strategy eliminates the need to chemically modify cell surfaces and offers excellent cell specificity, binding efficiency, and stability. This proof‐of‐concept study establishes that multivalent bispecific aptamers linked on DNA‐nanoscaffolds can mediate cellular engagement, which could lead to their use in directing or guiding cell–cell interactions in many biological events.
Tuning Stamp Surface Energy for Soft Lithography of Polar Molecules to Fabricate Bioactive Small‐Molecule Microarrays
Authors: Vaish Amit , Shuster Mitchell J. , Cheunkar Sarawut , Weiss Paul S. , Andrews Anne M. 
Published: May 2011

AbstractSoft‐lithography‐based techniques are widely used to fabricate microarrays. Here, the use of microcontact insertion printing is described, a soft‐lithography method specifically developed for patterning at the dilute scales necessary for highly selective biorecognition. By carefully tuning the polar surface energy of polymeric stamps, problems associated with patterning hydrophilic tether molecules inserted into hydrophilic host self‐assembled monolayers (SAMs) are surmounted. Both prefunctionalized tethers and on‐chip functionalization of SAMs patterned by microcontact insertion printing enable the fabrication of small‐molecule microarrays. Substrates patterned with the neurotransmitter precursor 5‐hydroxytryptophan selectively capture a number of different types of membrane‐associated receptor proteins, which are native binding partners evolved to recognize free serotonin. These advances provide new avenues for chemically patterning small molecules and fabricating small molecule microarrays with highly specific molecular recognition capabilities.
Synthesis of Ag2S–Ag Nanoprisms and Their Use as DNA Hybridization Probes
Authors: Liu Bing , Ma Zhanfang 
Published: May 2011

AbstractA simple synthetic route to prepare Ag2S–Ag nanoprisms consists of the facile addition of Na2S to a solution of triangular Ag nanoprisms. The resulting Ag2S–Ag nanoparticles are more stable in solution than the original Ag nanoprisms, and two surface plasmon resonance (SPR) bands of the original Ag nanoprisms still remain. In addition, the SPR bands of the Ag2S–Ag nanoprisms are tunable over a wide range. The Ag2S–Ag nanoprisms can be directly bioconjugated via well‐established stable Ag2S surface chemistry with readily available sulfur coupling agents. The nanoprisms are used in the hybridization of functionalized oligonucleotides, and show promise as probes for future biosensing applications.