bluuebunny/crossref_metadata_2025 huggingface dataset:
Surface Functionalization of Polypropylene Film via UV‐Induced Photografting of N‐Vinylpyrrolidone/Maleic Anhydride Binary Monomers
Authors: Xing Chang‐Min , Deng Jian‐Ping , Yang Wan‐Tai
Published: May 2005

Summary: A polymeric surface with desirable wettability and versatile reactivity was facilely fabricated by UV‐induced surface photografting of N‐vinylpyrrolidone (NVP)/maleic anhydride (MAn) binary monomers, with polypropylene (PP) film as a model substrate. It was found that the photografting process of NVP/MAn is much faster than that of individual NVP or MAn; both the grafting efficiency (Eg) and grafting yield (Yg) reach a maximum at around 1:1 molar feed ratio of NVP to MAn. These results indicate that the electron donor‐acceptor monomers can synergistically promote surface photografting by a known charge‐transfer‐complex (CTC) mechanism. Moreover, the grafted NVP and MAn units cooperatively enhance the surface hydrophilicity; the water contact angle of the modified surface drastically decreases from the original 99.4° to less than 36° within 30 s of irradiation time. Subsequently, we demonstrated that the surface‐grafted succinic anhydride groups could readily perform a variety of organic reactions such as acidic/alkaline hydrolysis and esterification, which is expected to facilitate further surface functionalizations. Besides, the complexing reaction of surface pyrrolidone groups with iodine was investigated, which was followed by UV‐vis spectroscopy. The antimicrobial activity against Escherichia coli, Staphylococcus aureus and Candida albicans show that this unique iodine‐complexated surface has desirable antimicrobial property.

Surface photografting of NVP/MAn and post reactions of surface‐grafted anhydride groups and pyrrolidone groups.

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Surface photografting of NVP/MAn and post reactions of surface‐grafted anhydride groups and pyrrolidone groups.
Assessing shared understanding of economic exchange among children and adults
Authors: Gianinno Lawrence , Crittenden Victoria L.
Published: May 2005

Research into children's understanding of economic exchanges has been conducted within two major purviews. Psychologists and sociologists have examined children's understanding via age‐related developmental theories, and economists have focused upon measures of economic literacy. Anthropologists and sociologists have included noneconomic factors in examining the economic‐exchange practices of adults, but the role of such social or moral influences has not been examined within the context of children as consumers. With the use of this research foundation, the current research is one of the first reported attempts to include children and adults in the same study to determine if there is a shared understanding of economic exchanges. As such, the role of noneconomic factors as a part of the everyday economic‐exchange behavior of children was also examined. Study findings suggest that past research has underestimated children's understanding of the economic world, as the current research found that children, ages 7–12 years, exhibited many of the same facets of intuitive economic understanding as adults from their own community group. The findings also suggested that the influence of noneconomic variables becomes greater as children grow into adulthood. © 2005 Wiley Periodicals, Inc.
The interaction of retail density and music tempo: Effects on shopper responses
Authors: Eroglu Sevgin A. , Machleit Karen A. , Chebat Jean‐Charles
Published: May 2005

Research examining the effects of store environment on shoppers has found that a number of atmospheric cues have significant effects on shoppers' cognitive, affective, and behavioral responses. To date, retail atmospheric cues have been studied in isolation, instead of simultaneously, like they occur in the retail setting. This study examines the interactive effects of two atmospheric cues—retail density and music tempo—and their impact on shopper responses within a real shopping environment. Based on the schema incongruity model, it is found that shopper hedonic and utilitarian evaluations of the shopping experience are highest under conditions of slow music/high density and fast music/low density. Significant main effects of music tempo are found for behavioral responses such as approach/avoidance tendency and extent of browsing behavior. The results underscore the need to examine interactive effects of atmospheric cues to better understand the impact of the store environment on shoppers. © 2005 Wiley Periodicals, Inc.
Understanding the mechanism and determinants of compromise effects
Authors: Sheng Shibin , Parker Andrew M. , Nakamoto Kent
Published: May 2005

In this article, compromise effects are distinguished theoretically from attraction effects, which have received more research attention in the past. This article proposes and tests expected‐loss minimization under decision uncertainty as the underlying mechanism to explain compromise effects. Next, it examines the effects of a consumer's familiarity with the product and attribute‐importance structure on compromise effects. The empirical results demonstrate the negative influences of familiarity and asymmetry of attribute importance on compromise effects, as well as the mediating effect of attribute importance on the familiarity–compromise‐effect relationship. Further research directions are also discussed. © 2005 Wiley Periodicals, Inc.
Clay Functionalization and Organization for Delamination of the Silicate Tactoids in Poly(L‐lactide) Matrix
Authors: Chen Guang‐Xin , Yoon Jin‐San
Published: May 2005

Summary: Three kinds of organoclay, i.e., Cloisite15A® (C15A), Cloisite20A® (C20A), and Cloisite30B® (C30B) were modified with silane to prepare twice functionalized organoclay (TFC). The pristine Cloisite® clays and the TFC were melt compounded with poly(L‐lactide) (PLLA) and morphology of the composites was observed to elucidate the effects of the d001 gallery distance, the epoxy content of TFC, and the compatibility between the organic ammonium surfactant and PLLA on the degree of exfoliation of the clay layers.

Plots of ITFC/ICloisite versus epoxy content for PLLA composites with (a) Cloisite15A® (C15A), (b) Cloisite20A® (C20A), (c) Cloisite30B® (C30B).

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Plots of ITFC/ICloisite versus epoxy content for PLLA composites with (a) Cloisite15A® (C15A), (b) Cloisite20A® (C20A), (c) Cloisite30B® (C30B).
Controlling the Deintercalation in Hydrogenated Nitrile Rubber (HNBR)/Organo‐Montmorillonite Nanocomposites by Curing with Peroxide
Authors: Gatos Konstantinos G. , Százdi László , Pukánszky Béla , Karger‐Kocsis József
Published: May 2005

Summary: The effect of peroxide vulcanization on organoclay dispersion in hydrogenated nitrile rubber (HNBR)/organo‐montmorillonite (organo‐MMT) nanocomposites was investigated. Three types of organoclays were tested, one containing a primary amine and two bearing quaternary intercalants. In contrast to sulfur vulcanization, which in combination with primary amine intercalants produced a confined/deintercalated clay structure, the peroxide curing yielded well‐ordered intercalated nanocomposites. The tensile mechanical performance and oxygen permeability of the HNBR nanocomposites were determined.

Oxygen permeability coefficient ratio for the different HNBR films tested at 0 and 60% relative humidity (i.e., dry and wet conditions, respectively).

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Oxygen permeability coefficient ratio for the different HNBR films tested at 0 and 60% relative humidity (i.e., dry and wet conditions, respectively).
Phase Separation and Organisation of Colloidal Spheres Suspended in Sheared Lyotropic Liquid‐Crystalline Polymers
Authors: Zhang Shanju , Terentjev Eugene M. , Donald Athene M.
Published: May 2005

Summary: Organisation behaviours of spherical particles suspended in sheared, lyotropic, liquid‐crystalline polymer solutions have been investigated using polarizing optical microscopy. We find that in a nematic phase the particles phase separate and adopt anisotropic chain‐like structures along the director. An earring defect is observed around a single particle whereas a cross or strings defect between neighbouring particles is found to serve as a repulsive barrier to prevent the particles from contacting each other. A theoretical analysis is presented to explain this new phenomenon.

An optical micrograph of 0.01 wt.‐% glass spheres suspended in a nematic solution of 40 wt.‐% ethyl cellulose in chloroform under an external shear force.

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An optical micrograph of 0.01 wt.‐% glass spheres suspended in a nematic solution of 40 wt.‐% ethyl cellulose in chloroform under an external shear force.
In vitro characterization of an Fe8 cluster as potential MRI contrast agent
Authors: Rodríguez Elisenda , Roig Anna , Molins Elies , Arús Carles , Quintero María Rosa , Cabañas Miquel E. , Cerdán Sebastián , Lopez‐Larrubia Pilar , Sanfeliu Coral
Published: May 2005

The complex [(tacn)6Fe8(µ3‐O)2(µ2‐OH)12]Br8·9H2O (Fe8) was evaluated in vitro as a new kind of possible MRI contrast agent. Relaxivities were measured at 1.41 and 9.4 T for Fe8 and commercial Gd‐DTPA dissolved in PBS. There was significant difference for r1 and r2 values between Fe8 and Gd‐DTPA at high field (9.4 T) and for r1 at low field (1.4 T) (p<0.05). Phantom studies with T1‐weighted MRI at 9.4 T suggest T1 contrast potential for Fe8. That is, up to 5.2 times higher intensity enhancement with respect to that of equimolar Gd‐DTPA was obtained with an Fe8 concentration, referred to the whole molecule, of 0.2 mM, for which no toxicity on C6 cells could be detected. No toxic effects on cultured C6 cells were observed up to a concentration of 1 mM Fe8. Copyright © 2005 John Wiley & Sons, Ltd.
Interior numerical approximation of boundary value problems with a distributional data
Authors: Babuška Ivo , Nistor Victor
Published: May 2005

We study the approximation properties of a harmonic function u ∈ H1−k(Ω), k > 0, on a relatively compact subset A of Ω, using the generalized finite element method (GFEM). If Ω = 𝒪, for a smooth, bounded domain 𝒪, we obtain that the GFEM‐approximation uS ∈ S of u satisfies ‖u − uS‖ ≤ Chγ‖u‖, where h is the typical size of the “elements” defining the GFEM‐space S and γ ≥ 0 is such that the local approximation spaces contain all polynomials of degree k + γ. The main technical ingredient is an extension of the classical super‐approximation results of Nitsche and Schatz (Applicable Analysis 2 (1972), 161–168; Math Comput 28 (1974), 937–958). In addition to the usual “energy” Sobolev spaces H1(𝒪), we need also the duals of the Sobolev spaces Hm(𝒪), m ∈ ℤ+. © 2005 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq, 2006
Least‐squares finite element method on adaptive grid for PDEs with shocks
Authors: Xue Jiaxing , Liao Guojun
Published: May 2005

We apply the least‐squares finite element method with adaptive grid to nonlinear time‐dependent PDEs with shocks. The least‐squares finite element method is also used in applying the deformation method to generate the adaptive moving grids. The effectiveness of this method is demonstrated by solving a Burgers' equation with shocks. Computational results on uniform grids and adaptive grids are compared for the purpose of evaluation. The results show that the adaptive grids can capture the shock more sharply with significantly less computational time. For moving shock, the adaptive grid moves correctly with the shock. © 2005 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq, 2006
Numerical solution to the optimal birth feedback control of a population dynamics: viscosity solution approach
Authors: Guo Bao‐Zhu , Sun Bing
Published: May 2005

This paper is concerned with the optimal birth control of a McKendrick‐type age‐structured population dynamic system. We use the dynamic programming approach in our investigation. The Hamilton–Jacobi–Bellman equation satisfied by the value function is derived. It is shown that the value function is the viscosity solution of the Hamilton–Jacobi–Bellman equation. The optimal birth feedback control is found explicitly through the value function. A finite difference scheme is designed to obtain the numerical solution of the optimal birth feedback control. The validity of the optimality of the obtained control is verified numerically by comparing with different controls under the same constraint. All the data utilized in the computation are taken from the census of the population of China in 1989. Copyright © 2005 John Wiley & Sons, Ltd.
Organic light‐emitting devices having chemically‐doped arylamine oligomer as a hole injection layer
Authors: Ito Takayuki , Asaka Jiro , Dao Kinh Luan Thanh , Kido Junji
Published: May 2005

A soluble and thermally stable arylamine oligomer containing difluorenyl groups was prepared and applied to organic light‐emitting devices (OLEDs) as a hole injection layer. The oligomer layer was doped with a Lewis acid and formed by spin coating from the dichloroethane solution. The OLED with a structure of indium tin oxide (ITO)/Lewis‐acid‐doped arylamine oligomer/N,N′‐dinaphthyl‐N,N′‐diphenyl bendizine (α‐NPD)/tris(8‐quinolinolato)aluminum(III) (Alq3)/LiF/Al showed lower drive voltages and higher power efficiencies, compared with the devices without the hole injection oligomer layer. Copyright © 2005 John Wiley & Sons, Ltd.
Distinct endoplasmic reticulum stress responses are triggered during human liver transplantation
Authors: Emadali Anouk , Nguyên Duc Thang , Rochon Caroline , Tzimas Georges N , Metrakos Peter P , Chevet Eric
Published: May 2005

Injury due to cold ischaemia‐reperfusion (IR) represents a major cause of primary graft non‐function following human liver transplantation. This major cellular response translates into a dramatic decrease in intracellular ATP concentration during the ischaemic phase, thus sensitizing cells to reperfusion shock. We postulated that IR‐induced cellular damage might cause alterations of the secretory pathway, particularly at the level of endoplasmic reticulum (ER) function. Under these circumstances, the ER triggers an adaptive response named the ‘unfolded protein response’ (UPR). In this study, we show that the expression of BiP, CHOP/GADD153 and GADD34, known to be induced specifically upon ER stress, are differentially affected upon IR, thus suggesting that distinct ER stress responses are activated during each phase of transplantation. With an approach combining semi‐quantitative RT‐PCR and immunoblotting using phospho‐specific antibodies, we show that the IRE‐1 pathway is activated upon early ischaemia and, in a second phase, upon early reperfusion. This occurs through the atypical splicing of XBP‐1 mRNA, its translation into a transcriptionally active XBP‐1 protein and the subsequent increase in EDEM mRNA expression, and may also contribute to the observed reperfusion‐induced activation of MAPK/SAPK. In contrast, we demonstrate that the PERK pathway, leading to inhibition of cap‐dependent translation, is mainly activated upon reperfusion, as shown by PERK and eIF2α phosphorylation. PERK activation is detected restrictively in sinusoidal endothelial cells and could contribute to the exaggerated sensivity of this liver cell type to IR injury. These results correlate well with the observed defect in protein secretion and suggest that the biphasic ER stress response may influence liver secretory functions and, as a consequence, condition liver transplantation outcomes. Copyright © 2005 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Algorithms to identify colonic ischemia, complications of constipation and irritable bowel syndrome in medical claims data: development and validation
Authors: Sands Bruce E. , Duh Mei‐Sheng , Cali Clorinda , Ajene Anuli , Bohn Rhonda L. , Miller David , Cole J. Alexander , Cook Suzanne F. , Walker Alexander M.
Published: May 2005

Purpose

A challenge in the use of insurance claims databases for epidemiologic research is accurate identification and verification of medical conditions. This report describes the development and validation of claims‐based algorithms to identify colonic ischemia, hospitalized complications of constipation, and irritable bowel syndrome (IBS).

Methods

From the research claims databases of a large healthcare company, we selected at random 120 potential cases of IBS and 59 potential cases each of colonic ischemia and hospitalized complications of constipation. We sought the written medical records and were able to abstract 107, 57, and 51 records, respectively. We established a ‘true’ case status for each subject by applying standard clinical criteria to the available chart data. Comparing the insurance claims histories to the assigned case status, we iteratively developed, tested, and refined claims‐based algorithms that would capture the diagnoses obtained from the medical records. We set goals of high specificity for colonic ischemia and hospitalized complications of constipation, and high sensitivity for IBS.

Results

The resulting algorithms substantially improved on the accuracy achievable from a naïve acceptance of the diagnostic codes attached to insurance claims. The specificities for colonic ischemia and serious complications of constipation were 87.2 and 92.7%, respectively, and the sensitivity for IBS was 98.9%.

Conclusions

U.S. commercial insurance claims data appear to be usable for the study of colonic ischemia, IBS, and serious complications of constipation. Copyright © 2005 John Wiley & Sons, Ltd.
Proteomic profiling of facial development in chick embryos
Authors: Mangum Jonathan E. , Farlie Peter G. , Hubbard Michael J.
Published: May 2005

Craniofacial disorders are associated with one‐third of human birth defects but the underlying molecular and cellular causes remain poorly understood. Proteomics seems well‐placed to benefit this medically important area but the scarcity of embryonic tissues poses a major challenge. In this study, we applied a microsample proteomics strategy to investigate the first branchial arch, an embryonic structure crucial for facial development, and found that proteome analysis is both practicable and informative despite the scarcity of tissue. Exploiting the embryonic chick as a tractable source of accurately staged tissue, we developed a sequential extraction procedure to interface with one‐dimensional polyacrylamide gel electrophoresis (1‐D PAGE) and 2‐D PAGE. In 2‐D gels, about 8% of the visible proteome changed between embryonic days 3 and 5, and the identities determined for 21 proteins accorded with the rapid growth during this period. These results led to the first molecular identification of chicken alpha‐fetoprotein, and an unusual localisation of vimentin to endoderm. With over 470 protein spots accessible, this comparative proteomics approach has good prospects for providing new markers, functional hypotheses and genes to target in functional tests. A broader value of extending these approaches to facial development in other species and to other areas in embryology can be anticipated.
Preparation of protein extracts from recalcitrant plant tissues: An evaluation of different methods for two‐dimensional gel electrophoresis analysis
Authors: Carpentier Sebastien Christian , Witters Erwin , Laukens Kris , Deckers Peter , Swennen Rony , Panis Bart
Published: May 2005

This study focuses on the specific problems of protein extraction from recalcitrant plant tissues and evaluates several methods to bypass them. Sample preparation is a critical step in a two‐dimensional gel electrophoresis proteome approach and is absolutely essential for good results. We evaluated four methods: the classical trichloroacetic acid (TCA)/acetone precipitation, TCA/acetone precipitation and fractionation, an alternative based on fractionation and without precipitation, and phenol extraction methanol/ammonium acetate precipitation. We optimized the phenol extraction protocol for small amounts of tissue, which is essential when the study material is limited. The protocol was optimized for banana (Musa spp.) and was subsequently applied to two other plant species: apple (Malus domestica L.) and potato (Solanum tuberosum L.). Banana (Musa spp.) is a good representative of a “difficult” plant species since it contains many interfering metabolites. Only classical TCA/acetone precipitation and phenol extraction methods proved useful as standard methods. Both methods are associated with a minor but reproducible loss of proteins. Every extraction method and the subsequent analytical procedure have their physicochemical limitations; both methods should be investigated before selecting an appropriate protocol. The study, which is presented in this paper, is useful for guiding the experimental setup of many other nonmodel species, containing various interfering elements.
Holistic differential analysis of embryo‐induced alterations in the proteome of bovine endometrium in the preattachment period
Authors: Berendt Frank J. , Fröhlich Thomas , Schmidt Susanne E. M. , Reichenbach Horst‐Dieter , Wolf Eckhard , Arnold Georg J.
Published: May 2005

During the peri‐implantation period, molecular signaling between embryo and endometrium (layer of tissue lining the uterus lumen) is supposed to be crucial for the maintenance of pregnancy. To investigate embryo‐induced alterations in the proteome of bovine endometrium in the preattachment period (day 18), we used monozygotic cattle twins (generated by embryo splitting) as a model eliminating genetic variability as a source for proteome differences. One of the twins was pregnant after the transfer of two in vitro produced blastocysts, while the corresponding twin received a sham‐transfer and served as a nonpregnant control. The two‐dimensional fluorescence difference gel electrophoresis (2‐D DIGE) analysis of the endometrium samples of three twin pairs (pregnant/nonpregnant) revealed four proteins with significantly higher abundance (p < 10−9) in each sample derived from the pregnant animals: Rho GDP dissociation inhibitor beta; 20 alpha‐hydroxysteroid dehydrogenase (20 alpha‐HSD); soluble NADP+‐dependent isocitrate dehydrogenase 1; and acyl‐CoA‐binding protein. To verify the accuracy of the 2‐D DIGE quantification, the abundances of 20 alpha‐HSD were quantified by a targeted cleavable isotope‐coded affinity tag (ICAT) approach. The mass spectrometry‐based ICAT quantification matched perfectly the results obtained by 2‐D DIGE quantification, demonstrating the accuracy of our data. These results demonstrate that our model (monozygotic twins) in combination with the appropriate analytical tools is particularly suitable for the detection of the proteins involved in the embryo–maternal interactions.
Proteome profile of human urine with two‐dimensional liquid phase fractionation
Authors: Soldi Monica , Sarto Cecilia , Valsecchi Cristina , Magni Fulvio , Proserpio Vanessa , Ticozzi Davide , Mocarelli Paolo
Published: May 2005

Two‐dimensional liquid chromatography separation (2‐DL), based on chromatofocusing for first dimension and hydrophobicity for second, can be used as a complementary method to two‐dimensional gel electrophoresis (2‐DE). A platform now available, ProteomeLab PF 2D provided by Beckman Coulter, (Fullerton, CA, USA), assembles these methods in automation. This system was applied to resolve large numbers of urine proteins. Reproducibility and sensitivity in protein resolution were evaluated in this study using urines collected from male blood donors. About 1000 peaks were detected at a pH range of 4.0–8.5 by applying 1 mg of proteins. Furthermore, the same fractions showing peaks with high absorbance intensities in second dimension were collected and subjected to matrix‐assisted laser desorption/ionization‐time of flight/mass spectrometry analysis for identification. The results showed that the 2‐DL provides high reproducibility of two‐dimensional protein map, and lends fractions to subsequent mass spectrometry analysis without the further need for extraction or solubilization of samples as required for spots excised from 2‐DE gels. In addition, this system also allows to separate particularly proteins with 40–9 kDa molecular weight.
Glycoproteomics of N‐glycosylation by in‐gel deglycosylation and matrix‐assisted laser desorption/ionisation‐time of flight mass spectrometry mapping: Application to congenital disorders of glycosylation
Authors: Šagi Dijana , Kienz Petra , Denecke Jonas , Marquardt Thorsten , Peter‐Katalinić Jasna
Published: May 2005

A general strategy for the structural evaluation of N‐glycosylation, a common post‐translational protein modification, is presented. The methods for the release of N‐linked glycans from the gel‐separated proteins, their isolation, purification and matrix‐assisted laser desorption/ionisation‐mass spectrometry (MALDI‐MS) analysis of their mixtures were optimised. Since many glycoproteins are available only at low quantities from sodium dodecyl sulphate‐polyacrylamide gel electrophoresis or two‐dimensional gels, high attention was paid to obtain N‐glycan mixtures representing their actual composition in human plasma by in‐gel deglycosylation. The relative sensitivity of solid MALDI matrices for MS analysis of acidic N‐glycans was compared. The most favourable results for native acidic N‐glycans were obtained with 2,4,6‐trihydroxyacetophenone monohydrate/diammoniumcitrate as a matrix. This matrix provided good results for both neutral and acidic mixtures as well as for methylated N‐glycans. In the second part of this paper the potential of such an optimised MS strategy alone or in combination with high pH anion‐exchange chromatography profiling for the clinical diagnosis of congenital disorders of glycosylation is presented.
Substituent effects in 13C NMR spectra. Part II—Alicyclic rigid systems
Authors: Oszczapowicz Janusz , Oszczapowicz Irena
Published: May 2005

It 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

No 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

2,3,4,5,6‐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

Cytochrome 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

Onion 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

Propargyl 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

A 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

Midwest 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

This 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

Grouting 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

Orthogonal 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

The 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

Nanopores 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

Anisotropic 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

The 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

The 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

The 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

In 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

We 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

Position‐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)