bluuebunny/crossref_metadata_2025_split huggingface dataset:
Substituent effects in 13C NMR spectra. Part II—Alicyclic rigid systems
Authors: Oszczapowicz Janusz , Oszczapowicz Irena 
Published: May 2005

AbstractIt is shown that the 13C NMR chemical shifts of the α‐, β‐ and γ‐carbon atoms in various subtituted polycycloalkanes yield correlations of very good quality with the sets of substituent X increments common for all of them. For the β‐carbon atoms the slope of the correlation line depends on the angle between the XCα and CαCβ bonds, whereas for the γ‐carbon atoms it depends on the dihedral angle of the XCα and CβCγ bonds. The differences between the slopes of correlation lines provide satisfactory explanation for differences in the values of increments for the same sets of substituent in individual types of polycycloalkanes. Copyright © 2005 John Wiley & Sons, Ltd.
Computational study of the process of polymer swelling in organic solvents
Authors: Makitra R. , Midyana H. , Prystansky R. , Vasyutin Ya. , Bazylyak L. 
Published: May 2005

AbstractNo satisfactory quantitative relationships exist between polymer swelling parameters and some distinct physical‐chemical parameters of organic solvents producing this swelling. Such relationships can only be obtained by means of linear multiparameter equations, which take into account the energy needed for cavity formation in solvents and also solvation effects. The advantages of such an approach are supported by examples of the generalization of experimental data for the swelling of many polymers and coals. Copyright © 2005 John Wiley & Sons, Ltd.
Synthesis, isolation, and thermal behavior of polybutadiene grafted with poly(2,3,4,5,6‐pentafluorostyrene)
Authors: Paz‐Pazos Marta , Pugh Coleen 
Published: May 2005

Abstract2,3,4,5,6‐Pentafluorostyrene (PFS) was copolymerized with polybutadiene (PB) in tetrahydrofuran using benzoyl peroxide as the initiator at 50, 60, and 80 °C. The copolymerizations follow typical radical polymerization kinetics and behavior. The grafting parameters were evaluated as a function of monomer conversion, initiator concentration, and/or temperature by gel permeation chromatography of directly injected copolymerization mixtures. The grafting efficiencies and grafting ratios are most consistent with a system that terminates by combination and whose graft sites are generated by hydrogen abstraction of allylic radicals by primary initiator radicals. Pure graft copolymers were isolated by extracting unreacted PB into hexanes and PPFS homopolymer into acetone. The similarity of the glass transition temperatures of the PPFS grafts and the corresponding extracted PPFS homopolymers confirms that their lengths are approximately equal. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 2874–2891, 2005
Re‐examination of inhibitor resistance conferred by Qo‐site mutations in cytochrome b using yeast as a model system
Authors: Fisher Nicholas , Meunier Brigitte 
Published: May 2005

AbstractCytochrome b from yeast (Saccharomyces cerevisiae Meyer ex Hansen) provides a convenient model system for the study of Qo‐site inhibitor (QoI) resistance mutations from a variety of organisms. QoI resistance mutations from fungal plant pathogens (G143A and F129L), malaria agent Plasmodium sp (Y279C/S), and Pneumocystis carinii (L275F), an opportunistic pathogenic fungus of man, were introduced into yeast cytochrome b and their effect on the binding of a variety of natural (myxothiazol and stigmatellin) and synthetic (atovaquone, azoxystrobin and pyraclostrobin) inhibitors to the bc1 complex monitored. L275S (from a myxothiazol‐resistant yeast) was also re‐examined. Stigmatellin binding was relatively unaffected by the introduction of these mutations. Significant increases in resistance were observed for the strobilurin‐class inhibitors myxothiazol, azoxystrobin and pyraclostrobin, with the largest increase in resistance conferred by G143A. In contrast, atovaquone binding was most effected by Y279C/S and L275S. Notably, F129L, G143A and L275S had a minor effect on bc1 activity, and so are unlikely to confer significant fitness penalties in vivo. These data are discussed in the light of the atomic structures for myxothiazol‐ and azoxystrobin‐inhibited bovine bc1 which have recently become available. We propose that QoI resistance due to G143A arises from steric hindrance between the inhibitor and cytochrome b, whereas the mechanism of resistance for the other mutations is due to an increase in binding energy between the protein and inhibitor molecule. Site‐directed mutagenesis was also used to model selected regions of the mammalian Qo site in yeast cytochrome b in order to further understand the differential efficacy of these QoI in the mammalian and pathogen bc1 complexes. Copyright © 2005 Society of Chemical Industry
Resistance of Thrips tabaci to pyrethroid and organophosphorus insecticides in Ontario, Canada
Authors: MacIntyre Allen Jennifer K , Scott‐Dupree Cynthia D , Tolman Jeff H , Ron Harris C 
Published: May 2005

AbstractOnion thrips, Thrips tabaci Lindeman, were collected from commercial onion fields in 2001, 2002 and 2003 to assess resistance to lambda‐cyhalothrin, deltamethrin and diazinon. In 2001, six of eight adult populations were resistant to lambda‐cyhalothrin, with resistance ratios (RR) ranging from 2 to 13.1 and four of these were also resistant to deltamethrin, with RR ranging from 19.3 to 120. Three of four adult populations were resistant to diazinon with RR ranging from 2.5 to 165.8. In 2002, four of seven nymphal populations and three of six adult populations were resistant to deltamethrin, with RR ranging from 4.3 to 72.5 and 9.4 to 839.2, respectively. Only one of six nymphal populations and one of five adult populations were resistant to diazinon, with RR of 5.6 and 2.3, respectively. In 2003 diagnostic dose bioassays, 15 of 16 onion thrips populations were resistant to lambda‐cyhalothrin and all were resistant to deltamethrin. Eight of the 16 were resistant to diazinon. These results indicate that insecticide resistance is widespread in onion thrips in commercial onion fields in Ontario. Copyright © 2005 Society of Chemical Industry
The potential efficiency of irrigation management and propargyl bromide in controlling three soil pests: Tylenchulus semipenetrans, Fusarium oxysporum and Echinochloa crus‐galli
Authors: Allaire Suzanne E , Yates Scott R , Zhang Ping , Ernst Fred F 
Published: May 2005

AbstractPropargyl bromide (3‐bromopropyne, 3BP) is a potential alternative for methyl bromide. Little information is available about its efficiency in controlling pests. The purpose of this paper is to estimate the 3BP dose required for killing three pests and to compare the efficiency of water management approaches to that of fumigation. The pests, Fusarium oxysporum Schlecht (fungus), Echinochloa crus‐galli (L) Beauv (grass) and Tylenchulus semipenetrans Cobb (nematode) were exposed to different 3BP concentrations in a sandy loam at 30 °C in a closed system. The lethal dose for killing 90% of the population (LD90) was calculated from the total applied mass, and varied from 0.3 µg g−1 soil for the nematode, 3 µg g−1 for the grass, and 9 µg g−1 for the fungus. The concentration–time index for killing 90% of the population (CT90) was 11 µg g−1 h for the nematode, 112 µg g−1 h for the grass and 345 µg g−1 h for the fungus. 3BP seems as efficient as other fumigant alternatives in controlling these pests. Using an open system, it was shown that the volume of soil in which the pests were controlled varied for different irrigation managements. Even 96 h after fumigation (with a concentration 10 times higher than would potentially be applied in the field), more than 20% of the soil volume had not reached the fungus and grass CT90 of the non‐irrigated soil. The soil underneath the furrow and the bed reached CT90 only slowly in all irrigated treatments even though techniques for increasing efficiency were used (tarping, surface sealing with water and high application rate). Copyright © 2005 Society of Chemical Industry
Synthesis, crystal structure and biological activity of aryl [(N,N′‐diacyl‐N′‐tert‐butylhydrazino)thio]methylcarbamates
Authors: Shang Jian , Wang Qing Min , Huang Run Qiu , Mao Chun Hui , Chen Li , Bi Fu Chun , Song Hai Bin 
Published: May 2005

AbstractA series of novel aryl [(N,N′‐diacyl‐N′‐tert‐butylhydrazino)thio]methylcarbamates were synthesized by the reaction of aryl (chlorothio)methylcarbamates with N,N′‐diacyl‐N‐tert‐butylhydrazines in the presence of sodium hydride. X‐Ray single crystal diffraction of 2‐isobutylphenyl [(N,N′‐dibenzoyl‐N′‐tert‐butylhydrazino)thio]methylcarbamate demonstrated the presence of NSN bonding. All of the compounds exhibited excellent larvicidal activities. Toxicity assays indicated that the products had knockdown activities of aryl methylcarbamates at higher concentrations and insect growth regulator activities of diacylhydrazines at lower concentrations. Copyright © 2005 Society of Chemical Industry
Differential response of Amaranthus tuberculatus (Moq ex DC) JD Sauer to glyphosate
Authors: Zelaya Ian A , Owen Micheal DK 
Published: May 2005

AbstractMidwest USA farmers have reported inconsistent control of Amaranthus tuberculatus (= rudis) (Moq ex DC) JD Sauer by glyphosate in glyphosate‐resistant crops. The potential of selection for decreased A tuberculatus sensitivity to glyphosate was therefore investigated in a reportedly resistant Everly, IA population (P0–EV). Evaluation of six A tuberculatus populations from the Midwest USA estimated a seedling baseline sensitivity of 2.15 mM glyphosate. Based on these results, three generations of divergent recurrent selection were implemented on P0–EV to isolate resistant and susceptible populations. A seedling assay was developed to screen large amounts of seeds and thus expedite the selection process. Whole‐plant and seedling rate responses of P0–EV and a known pristine A tuberculatus population from Paint Creek, OH (P0–WT) identified no significant difference in response to glyphosate; however, greater phenotypic variance was ostensibly evident in P0–EV. The first recurrent generation selected for resistance at 3.2 mM glyphosate (RS1–R) had a 5.9‐ and 1.7‐fold resistance increase at the seedling and whole‐plant levels, respectively, compared with the susceptible generation selected at 32 µM glyphosate. After three cycles of recurrent selection, 14.6‐fold difference in resistance at the seedling level and 3.1‐fold difference at the whole‐plant level were observed when comparing the populations selected for resistance (RS3–R) and susceptibility (RS3–S). Overall, recurrent selection increased the frequency of resistant individuals and decreased the variability to glyphosate at the population level. Nevertheless, variability for glyphosate resistance was still evident in RS3–R. Results herein suggested that A tuberculatus is inherently variable to glyphosate and that selection decreased the sensitivity to glyphosate. We purport that evolved glyphosate resistance in A tuberculatus may require multiple cycles of selection under field conditions. Historic estimated use of glyphosate alludes to the evolution of tolerant weed populations. Copyright © 2005 Society of Chemical Industry
Innovative strategies for seismic retrofitting of steel and composite structures
Authors: Di Sarno L , Elnashai A S 
Published: May 2005

AbstractThis paper reviews briefly traditional rehabilitation methods and provides a detailed discussion of design issues along with the advantages and the disadvantages of innovative strategies for seismic retrofitting of steel and composite structures. Special emphasis is placed on base isolation and supplemental damping devices. The viability and cost‐effectiveness of these strategies are assessed on the basis of multiple limit states within the framework of performance‐based design. A number of parameters which govern the selection of the intervention devices are investigated.
Grouting of cracks in concrete dams: numerical modelling and structural behaviour
Authors: Javanmardi Farrokh , Léger Pierre 
Published: May 2005

AbstractGrouting is often considered to reinstate water tightness and displacement continuity in cracked concrete dams. Grouting alters the state of stress, deformation, and the strength of a dam in many ways. The state of stress prior to grouting is altered by the injection pressure that often increases the crack opening. This new state of stress will be ‘locked‐in’ as the grout sets. Excessive injection pressure may also induce hydro‐fracturing. Obviously, composite action of structurally repaired cracks will be fully effective only for incremental load applications occurring after the completion of the grouting programme.The state‐of‐practice concerning structural response of cracked dams during and after grout injection is reviewed in this paper. The existing methods for structural analysis of dam rehabilitation by crack grouting, and the required modifications for modelling the hardened grout in the repaired dam are discussed. State‐of‐the‐art techniques using contact elements are defined (i) to model the hardened grout in cracks of repaired dam; and (ii) to investigate the structural response of the rehabilitated dam to subsequent loading conditions. A 90 m high‐gravity dam is considered in comparative analyses for numerical simulations of the incidence of grouting on the structural responses of cracked dams.
Immunoassays in a porous silicon interferometric biosensor combined with sensitive signal processing
Authors: Tinsley‐Bown A. , Smith R. G. , Hayward S. , Anderson M. H. , Koker L. , Green A. , Torrens R. , Wilkinson A.‐S. , Perkins E. A. , Squirrell D. J. , Nicklin S. , Hutchinson A. , Simons A. J. , Cox T. I. 
Published: May 2005

AbstractOrthogonal subspace signal processing algorithms (OSPA) have been developed to extract the optical thickness of a porous silicon layer to within one part in 105 from its reflectivity spectrum. This is equivalent to a limit of detection (LOD) of ∼40 pm change in optical thickness for a 3 µm thick layer, or an LOD of 1/2000 of a monolayer coverage with antibodies, of molecular weight 160 k Daltons, within a layer with pores of 100 nm diameter. A large molecule {horseradish peroxidase (HRP), MWt 40 kDa} has been detected at a concentration of 1 µg/ml by measuring its direct binding to anti‐HRP antibodies immobilised within a porous silicon layer. A competitive assay has been demonstrated for the detection of a small molecule {2, 4, 6 trinitrotoluene (TNT), MWt 227 Da} at 10 µg/ml. The projected LODs for HRP and TNT by these assays are 50 ng/ml and 1 µg/ml respectively. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Chemical modification of silicon surfaces for biological applications
Authors: Schwartz Michael P. , Cunin Frédérique , Cheung Ronnie W. , Sailor Michael J. 
Published: May 2005

AbstractThe attachment of poly(ethylene glycol) to porous Si surfaces via Si–C bonds using simple chemical techniques and commercially available starting materials is described. Poly(ethylene glycol) (PEG) is often used to prevent nonspecific binding for a variety of biological applications. The covalent attachment of a short‐chain PEG linker leads to a hydrophilic surface that is capable of admitting sucrose and bovine serum albumin (BSA) while leaving an acid terminus that can be used for further biological modification. Response of the linker‐modified porous Si surface to introduction of sucrose in aqueous solutions is assessed. This PEG linking chemistry should also be a generally useful biological attachment scheme that can be applied to crystalline silicon surfaces. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Investigation of p‐type macroporous silicon formation
Authors: Lévy‐Clément C. , Lust S. , Mamor M. , Rappich J. , Dittrich Th. 
Published: May 2005

AbstractNanopores and macropores can be formed electrochemically on p‐type silicon depending on the silicon resistivity and composition of the electrolyte. In order to understand if the structural dimensionality of the porous p‐type Si, either nanopore or macropore formation, depends on the electrochemical process at the Si/electrolyte interface, in situ pulsed surface photovoltage (SPV) and photoluminescence (PL) measurements have been undertaken. The SPV and PL studies have been made as a function of the applied current density as well as the electrolyte composition (aqueous or in presence of organic solvent) and the silicon doping density. Main results show that the Si surface is well passivated with preferential formation of ionic species and the Si band bending is around 100 mV, during porous Si formation. It varies slightly with the doping density, but is not affected by the composition of the electrolyte (HF/water and HF/organic solvent). This demonstrates that the chemistry of the electrolyte plays a major role in the formation of macroporous and nanoporous Si, but has still to be determined. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Silicon based optical devices – photonic applications of anisotropically nanostructured silicon
Authors: Diener J. , Künzner N. , Gross E. , Kovalev D. , Fujii M. 
Published: May 2005

AbstractAnisotropic nanostructuring of bulk silicon (Si) wafers leads to a significant in‐plane optical anisotropy of single porous silicon (PSi) layers. Additionally a variation of the etching current in time allows a controlled modification of the porosity along the growth direction and therefore a three‐dimensional variation of the refractive index (in‐plane and in‐depth). This technique can be important for photonic applications since it is the basis of a development of a variety of novel, polarization‐sensitive, silicon‐based optical devices: retarders, dichroic Bragg reflectors, dichroic microcavities and planar Si‐based polarizers. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Wedge‐shaped layers from porous silicon: the basics of laterally graded interference filters
Authors: Bohn H. G. , Marso M. 
Published: May 2005

AbstractThe process of making laterally graded interference filters has been reanalyzed. A simple and consistent picture arises if one applies a constant electric field perpendicular to the etch current instead of a constant current. The system is quantitatively modeled by means of a pure ohmic equivalent circuit model. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Pore formation on p‐type InP(100)
Authors: Schlierf U. , Lockwood D. J. , Graham M. J. , Schmuki P. 
Published: May 2005

AbstractThe present work deals with anodization processes of p‐type InP(100) in different halogenic acids. The morphology of the attack depends strongly on the electrochemical conditions and the type of anion present in the electrolyte. Only electropolishing was observed in HCl while the formation of a porous oxide layer was obtained in HF. In HBr, however, pore growth into the bulk material can be achieved. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Role of microstructure and layer thickness in porous silicon conductometric gas sensors
Authors: Gaburro Z. , Oton C. J. , Ghulinyan M. , Pancheri L. , Pavesi L. , Capuj N. 
Published: May 2005

AbstractThe electrical injection in porous silicon fabricated with heavily doped p‐type silicon is very sensitive to NO2. The known effect is an injection increase associated to NO2. We show experimentally a strong correlation between two structural properties and the sensitivity of electrical injection to NO2. The first property is the microstructure, i.e. the pore morphology at nm scale. A structure with straight, elongated pores shows large sensitivity, as opposed to a branching structure. The second property is the layer thickness, which determines the sign of the effect of NO2. If the thickness is sufficiently low – of the order of few µm – the injection in presence of NO2 decreases, instead of increasing. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Force modulation microscopy of multilayered porous silicon samples
Authors: Sbrana F. , Ghulinyan M. , Pavesi L. 
Published: May 2005

AbstractIn this paper we report on Force Modulation Microscopy (FMM) study and force‐distance curve analysis of porous silicon layers grown on silicon. The characterization has been carried out on the cross section of porous silicon. The FMM images allowed us to investigate the morphological thickness of the layers through local elasticity differences resolving both between porous silicon layers of different porosities and between porous silicon and silicon itself. Force‐distance curves showed different adhesion behaviour: porous silicon is more hydrophobic than bulk silicon in cross sectional view. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A new method for luminescent porous silicon formation: reaction‐induced vapor‐phase stain etch
Authors: de Vasconcelos Elder A. , da Silva E. F. , dos Santos B. E. C. A. , de Azevedo W. M. , Freire J. A. K. 
Published: May 2005

AbstractWe report a new method to form reproducible luminescent porous silicon layers in p‐type and n‐type substrates of low and high resisivity, with minimum apparatus and maximum simplicity. No equipment, formation of electrical contacts, illumination or addition of surfactants is needed. The porous silicon layer is formed by exposing the Si surface to the vapor generated by a dissolution reaction of a metal or Si in a HF/HNO3 mixture. The PL spectra of the layers have peaks located from 1.85 eV to 2.1 eV. The current–voltage characteristics of Al/PS/p‐Si/Al devices formed on these layers are rectifying and follow an exponential dependence at low forward bias and a power law at high forward bias. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Maskless patterning of various kinds of metals onto porous silicon
Authors: Sasano J. , Schmuki P. , Sakka T. , Ogata Y. H. 
Published: May 2005

AbstractPosition‐selective electrodeposition of various kinds of metals onto porous silicon (PS) with laser illumination is investigated. Maskless patterning of not only Ni, Fe, and Zn, less noble metals, but also Cu, a noble metal, was achieved by suppressing the immersion plating with chloride ions. The photo‐electrochemical behavior for each solution is compared. Similar results were obtained, especially in the cases of the less noble metals, indicating that the band structures of PS are in the similar condition. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A novel process for the preparation of thick porous silicon layers with very high porosity
Authors: Feyh A. , Laermer F. , Kronmüller S. , Mokwa W. 
Published: May 2005

AbstractA novel process for the preparation of thick porous silicon layers having very high porosities is proposed. Starting with thick layers of intermediate porosity the porosity is further increased in an additional step. This is done by means of controlled partial oxidation of the silicon skeleton followed by selective removal of the oxide film in an HF vapor phase etching process. Due to this, porosities beyond 90% are accessible since any further liquid phase contact is avoided and therefore no additional drying steps are necessary. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Electron beam irradiation of porous silicon for application in micromachining and sensing
Authors: Borini S. , Rocchia M. , Rossi A. M. , Boarino L. , Amato G. 
Published: May 2005

AbstractWe have studied the effect of the electron beam (EB) irradiation on porous silicon (PS), in order to find new possibilities for the local modification of the material at the submicrometer scale. The interaction between the accelerated electrons and PS has been investigated by means of two main techniques: infrared spectroscopy and profilometric measurements. All the results show that a strong increase of reactivity is induced on PS surface under exposure to the EB, due to the hydrogen desorption provoked by the incident electrons. We demonstrate that this phenomenon can be exploited for both the lateral structuring and the local functionalization of PS, at the submicrometer scale, depending on the different treatments applied to the samples after the EB bombardment. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)