bluuebunny/crossref_metadata_2025_split huggingface dataset:
Micropatterning and Impedance Characterization of an Electrically Percolating Layer‐by‐Layer Assembly
Authors: Everett W. Neil , Jan C. Jason , Sue H.‐J. , Grunlan Jaime C. 
Published: March 2007

AbstractMicropatterned layer‐by‐layer (LbL) assemblies were studied as a potential platform for sensor applications by performing impedance characterization throughout a range of electrolyte concentrations. Conductive LbL thin films were prepared with carbon black nanoparticles dispersed in the polymer matrix to provide an electrically conductive network. LbL assemblies were micropatterned using a photolithographic lift‐off method, and a test circuit was constructed as multiple interdigitating coplanar electrodes. Impedance spectra were collected between 104 and 106 Hz within a flow cell containing NaCl solutions ranging from 0.001–1.0 M. These preliminary results demonstrate the ability to pattern conductive LbL composites and underscore the potential utility and shortcomings of their use in sensor applications.
Simultaneous Determination of Ascorbic Acid and Uric Acid by Using a PVC/TTF‐TCNQ Composite Electrode as Detector in a FIA System
Authors: Cano Manuel , Palenzuela Beatriz , Ávila J. Luis , Rodríguez‐Amaro Rafael 
Published: March 2007

AbstractA PVC/TTF‐TCNQ composite electrode has been employed as detector in a flow injection system. The proposed method allows the simultaneous detection of ascorbic acid (AA) and uric acid (UA) in mixtures by using a FIA system in a simple manner, without pre‐treatment or modified electrode. This method is based on the amperometric determination of (a) ascorbic acid at 0.15 V and (b) both analytes at 0.35 V, being the response linear in the range 1×10−2–4×10−4 M for both analytes with detection limits (S/N=3) of 1.2×10−4 M and 8.1×10−5 M for AA and UA, respectively.
Clinical mitochondrial dysfunction in uninfected children born to HIV‐infected mothers following perinatal exposure to nucleoside analogues
Authors: Benhammou Valérie , Tardieu Marc , Warszawski Josiane , Rustin Pierre , Blanche Stéphane ,   on behalf of the French Perinatal Cohort
Published: March 2007

AbstractClinical and biological observations of mitochondrial dysfunction in children exposed to zidovudine (azidothymidine, AZT) during the perinatal period rapidly followed similar observations in animal experiments. To date, two different disorders have been identified. The first, asymptomatic hyperlactatemia, is observed during treatment in one third of exposed newborns, and is reversible with treatment cessation. In rare cases, it is associated with symptomatic acidosis. Regression may be slow, taking up to several months after the end of the treatment. The long‐term clinical consequences of this biochemical disturbance are unknown. The second disorder involves severe neurological symptoms, which become clinically detectable during the first 2 years of life. These symptoms are associated with a series of biochemical and ultrastructural changes consistent with persistent mitochondrial dysfunction. This latter phenomenon is rare, and affects only 0.3–0.5% of exposed children in the French pediatric cohort, in which observations continue. Despite initial controversy, several similar observations in other cohorts have since confirmed its occurrence. The pathophysiology of these two mitochondrial dysfunctions may differ. Continued efforts to identify and understand clinical mitochondrial toxicities are essential, given the intensification and diversification of perinatal prophylaxis strategies, and the number of pregnant women potentially involved. Environ. Mol. Mutagen. © 2007 Wiley‐Liss, Inc.
The meta‐analysis of the Italian studies on short‐term effects of air pollution (MISA): old and new issues on the interpretation of the statistical evidences
Authors: Bellini Pierantonio , Baccini Michela , Biggeri Annibale , Terracini Benedetto 
Published: March 2007

AbstractThe second meta‐analysis of the Italian studies on short‐term health effects of air pollution, known as MISA‐2, was based on daily time series of indicators of both pollution and of health outcomes. It covered 15 cities during 1996–2002 for a total population of approximately nine millions. Health outcomes included mortality for natural causes, for respiratory diseases and for cardiovascular conditions, as well as hospital admissions for respiratory, cardiac and cerebrovascular diseases. Pollutants considered in univariate analyses were sulphur dioxide (SO2), nitrogen oxide (NO2), carbon monoxide (CO), suspended particulate matter (SPM) measuring less than 10 µm diameter (PM10) and ozone (O3, limited to the summer period). Results, including risk estimates, have been largely confirmatory of findings obtained in previous large meta‐analytic studies carried out in North America and in Europe. A full report in Italian is available. The present contribution summarises the results of MISA‐2 and addresses three major issues regarding their interpretation: robustness of the causal inferential process, the role of specific air pollutants and the reliability of risk estimates. The former issue is stressed according to Bradford Hill's criteria and the conclusion is reached that at least for the association of air pollution with an increase in mortality the evidence for causality is strong. Assessing the role of each air pollutant is problematic: there is some evidence that the effects of PM10 are partly confounded by other pollutants, but PM10 may not be the best indicator of the role of air SPM (routine measures of PM2.5 have not been introduced in Italy). As for risk estimates, the per cent increase in risk of mortality for unit increase in PM10 concentration, measured in MISA‐2, is remarkably similar to estimates in other studies and there is indication for linearity of the dose–response relationship. Copyright © 2007 John Wiley & Sons, Ltd.
The establishment and degeneration of a temporary creek system in response to managed coastal realignment: The Wash, UK
Authors: Symonds Andrew M. , Collins Michael B. 
Published: March 2007

AbstractThe present investigation examines the growth and decay of an ephemeral creek system produced in response to a managed realignment at Freiston Shore, The Wash. In addition, the natural and anthropogenically enhanced developments of the creek system are compared.The creation of a managed realignment caused sheetflow to occur on the adjacent intertidal zone, approaching and throughout the period of low water, during spring tides. The resultant creek development led to annual headward (landward) extension rates of up to 400 m yr−1, over 20 times greater than those taking place during natural conditions. Rapid development of the creek system continued for 2 years, following initiation of the managed realignment. Over the succeeding 12 months, the creek system degenerated; it silted up and reverted to a similar pattern to its original geometry, prior to the managed realignment. Siltation of the creek system coincided with the cessation of sheetflow from the managed realignment. The natural creeks connected to the breaches in the embankment (as part of the scheme) became enlarged sufficiently to accommodate the increased flow produced by the drainage of the managed realignment site, without overbank flow occurring. The natural and anthropogenically enhanced developments of the creek system were similar to those described in the fluvial models described by Schumm et al. (1987): expansion by headward growth, followed by the extension of rapidly growing, long creeks, with tributaries added to fill the drainage network. Copyright © 2007 John Wiley & Sons, Ltd.
Rockglacier activity studies on a regional scale: comparison of geomorphological mapping and photogrammetric monitoring
Authors: Roer Isabelle , Nyenhuis Michael 
Published: March 2007

AbstractIn their spatial distribution as well as in their different states of activity, rockglaciers imply important information on former and recent permafrost conditions. Two different methods were applied in one study area (Turtmann Valley, Swiss Alps) in order to compare their suitability in assessing rockglacier activity. The comparison of geomorphological mapping and photogrammetric monitoring demonstrated a good accordance, especially on a regional scale. On a local scale, some differences in delimitation of the landforms as well as in the degree of activity were found. One reason for the observed differences is the qualitative character of geomorphological mapping resulting from the variable suitability of single parameters and combinations thereof in the determination of rockglacier activity.Based on these results, geomorphological mapping of rockglaciers can be improved by data from photogrammetric monitoring. Therefore, at best the two methods are combined when analysing former and present permafrost distribution. Copyright © 2007 John Wiley & Sons, Ltd.
Significance of geomorphological and subsurface drainage controls on failures of peat‐covered hillslopes triggered by extreme rainfall
Authors: Dykes Alan P. , Warburton Jeff 
Published: March 2007

AbstractOn 19 September 2003, 40 landslides of 140–18 000 m3 volume occurred within 2·5 km2 on the slopes of Dooncarton Mountain (Republic of Ireland) during a storm that may have exceeded 90 mm within 90 minutes. The landslides were investigated to determine the reasons for such a high density of slope failures. All of the landslides were surveyed within four months, and nine of them were investigated in detail. The six largest landslides, all peat failures, accounted for 57% of the more than 100 000 m3 of material displaced during the event. A consistent sequence of superficial materials was found on the failed hillslopes, including an extensive iron pan at the base of a buried soil horizon 0·3 m below the base of the peat. Morphologically, almost all of the landslides occurred on steep planar slopes or around sharp convexities, with the latter failures developing retrogressively upslope. The only significant relationship found from analysis of 371 subsurface pipes and 142 seepage cracks (defined here as contiguous fissures conducting concentrated subsurface flow) across all the failures was that the thinner the peat cover, the deeper the pipes and seepage cracks occurred below the base of peat. It is concluded that most of the landslides were probably caused by a combination of excess water pressures in the buried soil horizon and the thinner overburden of peat or peaty soil associated with the steeper slope segments. Pipes and seepage cracks formed on the iron pan probably existed prior to the failure event and may have contributed to the high water pressures as rainwater inputs exceeded their discharge capacities. One large peat slide was probably triggered by excess water pressures developed within and between artificial tine cuts. The properties of the blanket peat were generally of little consequence in the occurrence of the landslides, but relict desiccation cracks and other structural weaknesses through the peat mass were probably highly significant. Although several aspects of the peat failures correspond to previously published examples, the context of these failures in terms of the topography and upland catena is distinctive. Copyright © 2007 John Wiley & Sons, Ltd.
Evaluation of the constitutive parameters of a multiconductor transmission line model aimed at the representation of inductor windings at high frequencies
Authors: Brandão Faria J. A. 
Published: March 2007

AbstractThis paper is the first part of a work dedicated to the analysis and computation of the electric and magnetic behavior of inductor windings (e.g., power transformer windings) operating at high‐frequency regimes; a recognized key issue for very fast transient overvoltage studies. Here, the inductor winding, containing a total number of N turns, is modeled as a system of N‐coupled parallel conductors resembling a uniform inhomogeneous multiconductor transmission‐line structure (MTL) where proximity effects cannot be neglected. The characterization of the winding's equivalent MTL structure requires the specification and evaluation of its constitutive parameters, namely, the per‐unit‐length (PUL) capacitance and inductance matrices, and also the PUL resistance and conductance matrices, the latter two associated with losses. Close proximity between inductor turns together with the consideration of dielectric‐coated turns prevents the utilization of closed‐form expressions for the evaluation of most of the inductor constitutive parameters. Here we employ a harmonic expansion method (HEM) primarily aimed at the construction of the capacitance matrix from where the inductance and conductance matrices can be derived. A new theory based on Dubanton's approach but taking into account proximity effects related to eddy currents in the inductor core is also proposed and developed. This research paper provides, in a tutorial fashion, a comprehensive explanation of the details and approximations involved in the evaluation of the constitutive parameters of the MTL structure under analysis––an aspect that unfortunately is lightly tackled or even ill‐treated in the literature of winding models. Copyright © 2007 John Wiley & Sons, Ltd.
Determination of volatile organic compounds in English vineyard grape juices by immersion stir bar sorptive extraction–gas chromatography/mass spectrometry
Authors: Caven‐Quantrill Darren J. , Buglass Alan J. 
Published: March 2007

AbstractImmersion stir bar sorptive extraction–gas chromatography–mass spectrometry was used to analyse the volatile organic components of English vineyard grape juices. Four juices, Huxelrebe, Ortega, Schönburger and Siegerrebe, of the 2004 season, were from a commercial vineyard. The fifth, Madeleine Angevine 7672, of the 2000 vintage, was from a private vineyard. Madeleine Angevine juice exhibited the greatest number (113) of identified volatile components, followed by Siegerrebe, Huxelrebe, Schönburger and Ortega, with 78, 74, 70 and 69, respectively. Many compounds are common to all five varieties and very few of the more concentrated components are unique to a particular variety, except (E)‐anethole, estragole and methyl salicylate, which were unique to Madeleine Angevine, for these particular vintages. Of the compounds that are common to more than two varieties, Madeleine Angevine had the highest levels of (E)‐ethyl cinnamate, hexanol, (E)‐2‐hexenol, hotrienol, limonene and (E)‐methyl cinnamate. Siegerrebe had the highest concentrations of β‐citronellol, diendiol‐I, geraniol, dihydromethyl jasmonate, linalool (32 000 ng/l), (Z)‐ and (E)‐linalool oxide (both furanoid and pyranoid forms) and α‐terpineol. This variety also had high levels of 1‐hexanol, (E)‐2‐hexenal and (E)‐2‐hexenol. Huxelrebe had the highest concentrations of (E)‐2‐hexenal and (E)‐theaspirane; Schönburger had the highest levels of (Z)‐3‐hexenol, nerol and nerol oxide; and Ortega had the highest concentrations of β‐damascone and β‐damascenone. Copyright © 2007 John Wiley & Sons, Ltd.
A new approach to studying sponge cake aroma after storage in treated paper and plastic packaging by direct gas chromatography–olfactometry (D‐GC–O)
Authors: Dury‐Brun Cécile , Fournier Nicole , Pernin Karine , Guichard Elisabeth , Voilley Andrée 
Published: March 2007

AbstractThe objective of this study was to use D‐GC–O to compare the global odour of a sponge cake flavoured with either a ‘viennoiserie’ aromatic note or a simplified mixture of aroma compounds (used for physicochemical studies), then stored in a glass packaging (inert and impermeable) or in pouches made with treated papers or with plastic packaging, in accelerated ageing conditions (high temperature and relative humidity gradient). After 1 week of storage, the flavoured sponge cake headspace was SPME‐extracted directly into the packaging and analysed by D‐GC–O. The sponge cake global odour was better retained if plastic film rather than treated‐papers was used, for both flavourings. Changes in the relative proportions of aroma compounds in the sponge cake during storage modified the perceived global odour. This was due to their modified retention in the sponge cake and to their transfer through the packaging. SPME coupled to D‐GC–O was confirmed to be a rapid and sensitive method for comparing the aroma compound barrier properties of various packaging films with flavouring mixtures at concentrations close to reality. Copyright © 2007 John Wiley & Sons, Ltd.
Chemical composition and antimicrobial activity of essential oil of Ferula szovitsiana D.C.
Authors: Dehghan Gholamreza , Solaimanian Roya , Shahverdi Ahmad R. , Amin Gholamreza , Abdollahi Mohammad , Shafiee Abbas 
Published: March 2007

AbstractThe chemical composition of the essential oils obtained from stem/leaves and flowers/fruits of Ferula szovitsiana (Umbelliferae) were analysed by GC and GC–MS. The composition of the oils samples from stem/leaves and flower/fruits were compared: 51 and 47 compounds were identified in the essential oils of stem/leaves and flowers/fruits, representing 97.7% and 95.9% of the total oils, respectively. Both essential oils were rich in monoterpenes (66.7% and 62.1%, respectively) with neryl acetate as major component (33.0% and 41.5%, respectively). Other abundant compounds for stem/leaves oil were β‐caryophyllene (8.9%), α‐pinene (8.0%), β‐pinene (6.7%), bicyclogermacrene (4.5%), caryophyllene oxide (4.1%), limonene (4.6%) and α‐terpineol (3.2%). These values for flowers/fruits oil were bicyclogermacrene (9.0%), α‐pinene (5.5%), β‐pinene (3.9%), γ‐cadinene (3.5%), and calarene (3.2%). Furthermore, the oils were tested against Gram‐positive, Gram‐negative bacteria and two pathogenic fungi. It was found that oil from F. szovitsiana represents the most potent antimicrobial candidates with MIC of 1.25 mg/disk for Bacillus subtilis. Copyright © 2007 John Wiley & Sons, Ltd.
A modification of the artificial compressibility algorithm with improved convergence characteristics
Authors: Muldoon Frank , Acharya Sumanta 
Published: March 2007

AbstractThe artificial compressibility algorithm has a significant drawback in the difficulty of choosing the artificial compressibility parameter, improper choice of which leads either to slow convergence or divergence. A simple modification of the equation for pressure in the artificial compressibility algorithm which removes the difficulty of choosing the artificial compressibility parameter is proposed. It is shown that the choice of the relaxation parameters for the new algorithm is relatively straightforward, and that the same values can be used to provide robust convergence for a range of application problems. This new algorithm is easily parallelized making it suitable for computations such as direct numerical simulation (DNS) which require the use of distributed memory machines. Two key benchmark problems are studied in evaluating the new algorithm: DNS of a fully developed turbulent channel flow, and DNS of a driven‐cavity flow, using both explicit and implicit time integration schemes. The new algorithm is also validated for a more complex flow configuration of turbulent flow over a backward‐facing step, and the computed results are shown to be in good agreement with experimental data and previous DNS work. Copyright © 2007 John Wiley & Sons, Ltd.
Developing implicit pressure‐weighted upwinding scheme to calculate steady and unsteady flows on unstructured grids
Authors: Darbandi M. , Vakilipour S. 
Published: March 2007

AbstractThe finite‐volume methods normally utilize either simple or complicated mathematical expressions to interpolate the fluxes at the cell faces of their unstructured volumes. Alternatively, we benefit from the advantages of both finite‐volume and finite‐element methods and estimate the advection terms on the cell faces using an inclusive pressure‐weighted upwinding scheme extended on unstructured grids. The present pressure‐based method treats the steady and unsteady flows on a collocated grid arrangement. However, to avoid a non‐physical spurious pressure field pattern, two mass flux per volume expressions are derived at the cell interfaces. The dual advantages of using an unstructured‐based discretization and a pressure‐weighted upwinding scheme result in obtaining high accurate solutions with noticeable progress in the performance of the primitive method extended on the structured grids. The accuracy and performance of the extended formulations are demonstrated by solving different standard and benchmark problems. The results show that there are excellent agreements with both benchmark and analytical solutions as well as experimental data. Copyright © 2007 John Wiley & Sons, Ltd.
Adapting simulation codes to compute unstable solutions and bifurcation behaviour
Authors: Grande Beau B. , Tavener Simon J. , Thomas James W. 
Published: March 2007

AbstractSimulation codes for solving large systems of ordinary differential equations suffer from the disadvantage that bifurcation‐theoretic results about the underlying dynamical system cannot be obtained from them easily, if at all. Bifurcation behaviour typically can be inferred only after significant computational effort, and even then the exact location and nature of the bifurcation cannot always be determined definitively. By incorporating relatively minor changes to an existing simulation code for the Taylor–Couette problem, specifically, by implementing the Newton–Picard method, we have developed a computational structure that enables us to overcome some of the inherent limitations of the simulation code and begin to perform bifurcation‐theoretic tasks. While a complete bifurcation picture was not developed, three distinct solution branches of the Taylor–Couette problem were analysed. These branches exhibit a wide variety of behaviours, including Hopf bifurcation points, symmetry‐breaking bifurcation points, turning points and bifurcation to motion on a torus. Unstable equilibrium and time‐periodic solutions were also computed. Copyright © 2007 John Wiley & Sons, Ltd.
Simulations of the turbulent channel flow at Reτ = 180 with projection‐based finite element variational multiscale methods
Authors: John Volker , Roland Michael 
Published: March 2007

AbstractProjection‐based variational multiscale (VMS) methods, within the framework of an inf–sup stable second order finite element method for the Navier–Stokes equations, are studied in simulations of the turbulent channel flow problem at Reτ = 180. For comparison, the Smagorinsky large eddy simulation (LES) model with van Driest damping is included into the study. The simulations are performed on very coarse grids. The VMS methods give often considerably better results. For second order statistics, however, the differences to the reference values are sometimes rather large. The dependency of the results on parameters in the eddy viscosity model is much weaker for the VMS methods than for the Smagorinsky LES model with van Driest damping. It is shown that one uniform refinement of the coarse grids allows an underresolved direct numerical simulations (DNS). Copyright © 2007 John Wiley & Sons, Ltd.