bluuebunny/crossref_metadata_2025_split huggingface dataset:
Lithiation of 2‐Aryl‐2‐(chloroaryl)‐1,3‐dioxolanes and Its Application in the Synthesis of New ortho‐Functionalized Benzophenone Derivatives
Authors: Lukács Gyula , Porcs‐Makkay Márta , Simig Gyula 
Published: September 2004

Abstract2‐Aryl‐2‐(chloroaryl)‐1,3‐dioxolanes 4 were lithiated ortho to the ketal group of the chloroaryl ring by treatment with butyllithium in THF between −78 and 0 °C. The site selectivity of some of the deprotonation reactions was rationalized by the long‐range effect of the 4‐chloro substituent. The lithio species thus generated were treated with various electrophiles to give ortho‐functionalized benzophenone derivatives. Intramolecular competition between the aryl rings was observed in the lithiation of 2‐(4‐chlorophenyl)‐2‐(4‐fluorophenyl)‐1,3‐dioxolane (4s). (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Titanium Carbide Thin‐Film Electrodes: Characterization and Evaluation as Working Electrodes
Authors: Lupu Alina , Compagnone Dario , Orlanducci Silvia , Terranova Maria Letizia , Magearu Vasile , Palleschi Giuseppe 
Published: September 2004

AbstractTitanium carbide (TiC) polycrystalline thin films, obtained by a hybrid chemical vapor deposition/powder flowing technique, were characterized and used to assemble working electrodes. The potential window and the electrochemistry of standard redox couples ([Ru(NH3)6]3+, [Fe(CN)6]3−) have been investigated in cyclic voltammetry, demonstrating a behavior similar to glassy carbon electrodes. The quinone (Q)/hydroquinone(H2Q) redox couple presented an interesting quasireversible behavior(Ep=0.07 mV) , confirmed also for other quinones.
Selective Detection of Dopamine and Its Metabolite, DOPAC, in the Presence of Ascorbic Acid Using Diamond Electrode Modified by the Polymer Film
Authors: Roy Protiva Rani , Saha Madhu Sudan , Okajima Takeyoshi , Park Soo‐Gil , Fujishima Akira , Ohsaka Takeo 
Published: September 2004

AbstractThe surface of boron‐doped diamond (BDD) electrode is modified by the polymer film for the first time. The cationic polymer film of N,N‐dimethylaniline (DMA) is electrochemically deposited on BDD electrode surface. This polymer (PDMA) film‐coated BDD electrode is used as a sensor which selectively detect dopamine (DA) in the presence of ascorbic acid (AA). This electrode also can detect both DA and its metabolite, 3,4‐dihydroxy phenyl acetic acid (DOPAC) in the presence of AA in the range of the physiological concentrations of these species. Favorable ionic interaction (i.e., electrostatic attraction) between the PDMA film and AA or DOPAC lowers their oxidation potentials and enhances the current response for AA and DOPAC compared to that at the bare electrode. The PDMA film also shows a hydrophobic interaction with DA and DOPAC. In cyclic voltammetric measurements, the PDMA film‐coated electrode can successfully separate the oxidation potentials for AA and DA coexisting in the same solution and the separation is about 200 mV. AA oxidizes at more negative potential than DA. In square‐wave voltammetry, the sensitivity of the PDMA film‐coated BDD electrode for DA in the presence of higher concentration of AA is higher than that of the PDMA film‐coated glassy carbon electrode. The hydrodynamic amperometric experiments confirm that the oxidation of AA is not affected by the oxidized product of DA and vice versa. So, unlike the bare electrode the catalytic oxidation of AA by the oxidized DA is eliminated at the PDMA film‐coated BDD electrode. The sensitivities of the modified electrode for AA, DA and DOPAC, which are present in the same solution with their physiological concentration ratios, are calculated to be 0.070, 0.363 and 0.084 μA μM−1, respectively. The modified electrode exhibits a stable and sensitive response to DA.
Biomimetic Electroreduction of O2 by Hemoglobin in a Surfactant Film: Preliminary Electrochemical Impedance Spectroscopy Insight
Authors: Mimica Danica , Ringuedé Armelle , Agurto Claudio , Bedioui Fethi , Zagal José 
Published: September 2004

AbstractWe report in this study on the direct electron transfer for hemoglobin (Hb) entrapped in cationic didodecyldimethylammonium bromide (DDAB) surfactant films cast on vitreous‐carbon electrodes, in neutral aqueous solution. This was achieved by using for the first time the electrochemical impedance spectroscopy (EIS) measurements. This allows providing further insights in the electrical properties of these biofilms. The electroassisted catalytic reduction of molecular oxygen by the entrapped Hb, in neutral aqueous solution was also investigated. A catalytic current was observed close to the Fe(III)/Fe(II) redox potential of the immobilized Hb, and the intensity of the voltammetric cathodic peak (measured by cyclic voltammetry) is directly proportional to oxygen partial pressure. The influence of oxygen partial pressure on the impedance response of the films was also analyzed. The obtained results emphasizes the fact that the total charge transfer resistance of the modified electrode decreases with increasing oxygen partial pressure. A preliminary explanation of such an observation is discussed.
Gold Nanoparticle‐Catalyzed Silver Electrodeposition on an Indium Tin Oxide Electrode and Its Application in DNA Hybridization Transduction
Authors: Lee Thomas Ming‐Hung , Cai Hong , Hsing I‐Ming 
Published: September 2004

AbstractIn this work, we report a simple, rapid and sensitive approach for the electrochemical gold nanoparticle‐based DNA detection with an electrocatalytic silver deposition process. The catalytic and preferential silver electrodeposition on gold nanoparticle surfaces using an indium tin oxide (ITO) electrode at certain potentials, without any chemical pretreatments of the electrode, is demonstrated. More importantly, the application of this methodology for hybridization transduction is explored. The ITO electrode surface is first coated with an electroconductive polymer, poly(2‐aminobenzoic acid), to enable the chemical attachment of avidin molecules for the subsequent probe immobilization. The hybridization of the target with the probe in turn permits the binding of the gold nanoparticle labels to the transducer surface via biotin‐streptavidin interaction. The amount of bound gold labels, which is proportional to the amount of the target, is determined by the electrocatalytic silver deposition process. A significant improvement of the signal‐to‐background ratio is achieved with this scheme compared to the conventional chemical hydroquinone‐based silver deposition process.
Organic Phase Cyclopentadienylnickelthiolate Sensor System for Electrochemical Determination of Sulfur Dioxide
Authors: Morrin Aoife , Moutloali Richard M. , Killard Anthony J. , Smyth Malcolm R. , Darkwa James , Iwuoha Emmanuel I. 
Published: September 2004

AbstractA series of cyclopentadienylnickelthiolate complexes, [Ni(PBu3)(η5‐C5H5)(SC6H4X‐4)] (X=F, Cl, Br, NH2), were shown to express stable reversible electrochemical properties even after formation of SO2 adducts in organic phase consisting of argon purged CH2Cl2/0.1 M [n‐Bu4N][BF4]. The formal potentials (E°′) values of the compounds ranged from 265 to 431 mV/Ag‐AgCl depending on the para substituent of the benzene thiolate ligand. Electrochemical, UV‐vis and 1H NMR spectroscopic analyses show that the formation of SO2 adducts causes the perturbation of the electronic density of the nickel metal center, indicated by shifts in the E°′ values of the NiII/III redox couple that is dependent on SO2 concentration. The detection limits of the resulting organic phase electrochemical gas sensor system was as low as 0.56 ppm SO2 for the fluoro complex, while the linear range was as high as 700–2000 ppm SO2 for the amino complex.
Tracking sediment redistribution in a small watershed: implications for agro‐landscape evolution
Authors: Polyakov V. O. , Nearing M. A. , Shipitalo M. J. 
Published: September 2004

AbstractA new, multi‐tracer method is used to track erosion, translocation, and redeposition of sediment in a small watershed, thus allowing for the ﬁrst time a complete, spatially distributed, sediment balance to be made as a function of landscape position. A 0·68 ha watershed near Coshocton, Ohio, USA was divided into six morphological units, each tagged with one of six rare earth element oxides. Sediment translocation was evaluated by collecting run‐off and by spatially sampling the soil surface. Average measured erosion rate was 6·1 t ha−1, but varied between 40·4 t ha−1 loss from the lower channels to 24·1 t ha−1 gain on the toeslope. With this technique it was possible for the ﬁrst time to itemize the sediment budget for landscape elements into three components: (1) the soil from the element that left the watershed with run‐off; (2) soil from the element that was redeposited on lower positions, with the spatial distribution of that deposition; and (3) soil originating from the upper positions and deposited on the element, with quantiﬁcation of relative source areas. The results are incongruous with the current morphology of the watershed, suggesting that diffusion‐type erosion must also play a major role in deﬁning the evolution of this landscape. Copyright © 2004 John Wiley & Sons, Ltd.
Soil creep and convex‐upward velocity profiles: theoretical and experimental investigation of disturbance‐driven sediment transport on hillslopes
Authors: Roering Joshua J. 
Published: September 2004

AbstractThe movement of unconsolidated materials near the Earth's surface is often driven by disturbances that occur at a range of spatial and temporal scales. The nature of these disturbances ranges from highly variable, such as tree turnover, to periodic and predictable, such as frost heave or creep. To explore the effect of probabilistic disturbances on surface processes, we formulated a granular creep model with analogy to rate process theory (RPT) used for chemical reactions. According to the theory, individual particles must be energized to a height greater than adjacent particles in order for grain dilation and transport to occur. The height of neighbouring particles (which is akin to activation energy in chemical reactions) varies with slope angle such that energy barriers get smaller in the downslope direction as slopes steepen. When slopes approach the friction‐limited angle of repose, the height of energy barriers approaches zero and grains ﬂow in the absence of disturbance. An exponential function is used to describe the probability distribution of particle excitation height although alternative distributions are possible. We tested model predictions of granular dynamics in an experimental sandpile. In the sandpile, acoustic energy serves as the disturbance agent such that grains dilate and shear in response. Particle velocities are controlled by the frequency of energy pulses that result in grain displacement. Using tracer particles, we observed a convex‐upward velocity proﬁle near the surface of the sandpile, consistent with predictions of our RPT‐based velocity model. In addition, we depth‐integrated the velocity model to predict how ﬂux rates vary with inclination of the sandpile and observed non‐linear ﬂux–gradient curves consistent with model predictions. By varying the acoustic energy level in the experimental sandpile, we documented changes in the rate of grain movement; similar changes in modelled velocities were achieved by varying the exponent of the particle excitation probability distribution. The general agreement between observed and modelled granular behaviour in our simple laboratory sandpile supports the utility of RPT‐based methods for modelling transport processes (e.g. soil creep, frost heave, and till deformation), thus enabling us to account for the probabilistic nature of disturbances that liberate sediment in natural landscapes. Copyright © 2004 John Wiley & Sons, Ltd.
Godunov‐type adaptive grid model of wave–current interaction at cuspate beaches
Authors: Rogers Benedict D. , Borthwick Alistair G. L. , Taylor Paul H. 
Published: September 2004

AbstractThis paper presents a second‐order accurate Godunov‐type numerical scheme for depth‐ and period‐averaged wave–current interaction. A flux Jacobian is derived for the wave conservation equations and its eigensystem determined, enabling Roe's approximate Riemann solver to be used to evaluate convective fluxes. Dynamically adaptive quadtree grids are used to focus on local hydrodynamic features, where sharp gradients occur in the flow variables. Adaptation criteria based on depth‐averaged vorticity, wave‐height gradient, wave steepness and the magnitude of velocity gradients are found to produce accurate solutions for nearshore circulation at a half‐sinusoidal beach. However, the simultaneous combination of two or more separate criteria produces numerical instability and interference unless all criteria are satisfied for mesh depletion. Simulations of wave–current interaction at a multi‐cusped beach match laboratory data from the United Kingdom Coastal Research Facility (UKCRF). A parameter study demonstrates the sensitivity of nearshore flow patterns to changes in relative cusp height, angle of wave incidence, bed roughness, offshore wave height and assumed turbulent eddy viscosity. Only a small deviation from normal wave incidence is required to initiate a meandering longshore current. Nearshore circulation patterns are highly dependent on the offshore wave height. Reduction of the assumed eddy viscosity parameter causes the primary circulation cells for normally incident waves to increase in strength whilst producing rip‐like currents cutting diagonally across the surf zone. Copyright © 2004 John Wiley & Sons, Ltd.
Transient free‐surface flow of a viscoelastic fluid in a narrow channel
Authors: Khayat Roger E. , Pan Runling 
Published: September 2004

AbstractThe interplay between inertia and elasticity is examined for transient free‐surface flow inside a narrow channel. The lubrication theory is extended for the flow of viscoelastic fluids of the Oldroyd‐B type (consisting of a Newtonian solvent and a polymeric solute). While the general formulation accounts for non‐linearities stemming from inertia effects in the momentum conservation equation, and the upper‐convected terms in the constitutive equation, only the front movement contributes to non‐linear coupling for a flow inside a straight channel. In this case, it is possible to implement a spectral representation in the depthwise direction for the velocity and stress. The evolution of the flow field is obtained locally, but the front movement is captured only in the mean sense. The influence of inertia, elasticity and viscosity ratio is examined for pressure‐induced flow. The front appears to progress monotonically with time. However, the velocity and stress exhibit typically a strong overshoot upon inception, accompanied by a plug‐flow behaviour in the channel core. The flow intensity eventually diminishes with time, tending asymptotically to Poiseuille conditions. For highly elastic liquids the front movement becomes oscillatory, experiencing strong deceleration periodically. A multiple‐scale solution is obtained for fluids with no inertia and small elasticity. Comparison with the exact (numerical) solution indicates a wide range of validity for the analytical result. Copyright © 2004 John Wiley & Sons, Ltd.
Application of combined immunofluorescence and fluorescence in situ hybridization on paraffin‐embedded sections to characterize T‐cell lymphoma with EBV‐infected B‐cell blasts
Authors: Temple Genevieve K. , Sales Mark , Kernohan Neil , Scott Fiona , Meiklejohn David , Pratt Norman 
Published: September 2004

AbstractCombined immunofluorescence (IF) and fluorescence in situ hybridization (FISH) on formalin‐fixed, paraffin‐embedded tissue sections were used to examine lymph node tissue from two patients diagnosed with T‐cell lymphoma with Epstein–Barr virus (EBV)–infected B‐cell blasts. The majority of cells within the samples comprised T‐cells staining positively for CD3. In addition, both patients had a population of large pleiomorphic cells that were positive for the B‐cell marker CD20 and for EBV LMP‐1. Standard PCR clonality testing of the nodes revealed both immunoglobulin heavy chain (IGH) and T‐cell receptor (TCR) clonal rearrangements in one patient, although in the other case monoclonality was demonstrated only for TCRG. Cytogenetics of cultured lymphocytes from nodal tissue revealed two apparently unrelated abnormal clones in both patients. Combined IF and FISH revealed that these phenomena reflected two abnormal populations of B‐ and T‐cells rather than reactive B‐cell hyperplasia or biphenotypic evolution from a common ancestral lymphoma. True B‐cell malignancy probably emerged within a preexisting but unrelated T‐cell lymphoma. This is the first study to relate the phenotype of the abnormal cells in such cases to specific clonal populations of cells, and it demonstrates a method that may easily be introduced into a diagnostic cytogenetics laboratory with access to standard pathology laboratory resources. © 2004 Wiley‐Liss, Inc.
Generation of a conditional allele of the CBP gene in mouse
Authors: Zhang Zuwen , Hofmann Clementine , Casanova Emilio , Schütz Günther , Lutz Beat 
Published: September 2004

AbstractCREB‐binding protein (CBP) is an important transcriptional cofactor for various intracellular signaling pathways, including Ca2+‐ and cAMP‐mediated gene activation. The loss of one CBP allele causes the human Rubinstein‐Taybi syndrome, which is characterized by mental retardation and other severe developmental defects. Deletion of both CBP alleles in the mouse leads to early embryonic lethality. To address the function of CBP in late embryogenesis and in adult physiology, a floxed CBP allele (CBPfl) was generated. Using the Cre/loxP recombination system, CBP function was disrupted in principal forebrain neurons by breeding with a transgenic CaMKIIα‐Cre mouse line to obtain CBPfl/fl;CaMKIIαCre mice. These mice contain CBPstop523 alleles specifically in principal forebrain neurons, presumably resulting in the production of a truncated CBP protein unable to interact with a number of transcription factors, including phosphorylated CREB. genesis 40:82–89, 2004. © 2004 Wiley‐Liss, Inc.
The Drosophila RNA‐binding protein Lark is required for the organization of the actin cytoskeleton and Hu‐li tai shao localization during oogenesis
Authors: McNeil Gerard P. , Smith Fiona , Galioto Robert 
Published: September 2004

AbstractElimination of maternal expression of the Drosophila RNA‐binding protein Lark results in female sterility. Here we show that this is due to a requirement during oogenesis. Developing oocytes from lark1 germline clones (GLCs) are often smaller than normal due to defects in nurse cell cytoplasmic “dumping.” Late‐stage egg chambers from lark1 GLCs contain low levels of cortical and ring canal associated actin and completely lack nurse cell cytoplasmic F‐actin bundles, suggesting the “dumping” phenotype is due to a defect in the actin cytoskeleton. Localization of Hu‐li tai shao (Hts) protein, a component of ring canals, is also disrupted in these mutants. In addition to the dumpless phenotype, we observed a buildup of late‐stage egg chambers, a phenotype that correlates with the decrease in egg‐laying observed in the mutants. We postulate that this phenotype is due to defects in the cytoskeletal integrity of eggs since retained and oviposited eggs are fragile and often deflated. These mutant phenotypes are likely due to disruption of an RNA‐binding function of Lark as similar phenotypes were observed in flies carrying specific RNA‐binding domain mutations. We propose that Lark functions during oogenesis as an RNA‐binding protein, regulating mRNAs required for nurse cell transport or apoptosis. genesis 40:90–100, 2004. © 2004 Wiley‐Liss, Inc.
RNAi‐mediated inhibition of gene function in the follicle cell layer of the Drosophila ovary
Authors: Zhu Xianjun , Stein David 
Published: September 2004

AbstractRNA‐mediated interference (RNAi) has been reported to be an effective reverse genetic approach for studying gene function in various organisms. To assess RNAi as a means of examining genes expressed in ovarian follicle cells for their involvement in embryonic dorsal–ventral patterning, we tested the ability of transgenically expressed double‐stranded RNA (dsRNA) directed against the dorsal group gene windbeutel to generate phenotypic effects in the progeny of expressing females. We observed that expression in follicle cells under the control of Gal4 transcribed from the strong and widely expressed alphaTub84B or Actin5C promoters led to efficient dorsalization of progeny embryos. Surprisingly, a variety of strongly expressed follicle cell‐specific Gal4 enhancer trap lines failed to elicit an RNAi phenotype in combination with the windbeutel‐specific dsRNA. These results stress the importance of careful choice of expression system and of conditions for use in transgenic RNAi‐mediated studies of gene function. genesis 40:101–108, 2004. © 2004 Wiley‐Liss, Inc.
Sedimentary evidence for the formation mechanism of the Armoy moraine and late Devensian glacial events in the north of Ireland
Authors: Knight Jasper 
Published: September 2004

AbstractThe internal sedimentology of the Armoy moraine, which marks a late Devensian (Weichselian) incursion of Scottish ice into the north of Ireland, is described from a temporary exposure near Armoy village. The exposure (up to 30 m long, 10 m high) comprises folded gravel beds, massive clay grading up to pebbly diamicton, massive gravel, overfolded and deformed sand, and a gravel and massive diamicton cover. These sediments overlie glacially smoothed basalt bedrock. The sediment succession records the interaction of near‐touching Scottish and Irish ice margins, and the formation, infilling and drainage of an ice‐supported proglacial lake. Scottish ice likely advanced into the north of Ireland by a short‐lived glacier surge during the Killard Point Stadial (coeval with Heinrich Event 1 at 14.514C ka BP), forming the Armoy moraine at its maximum extent. The presence of rafted sediment blocks within the moraine suggests ice‐marginal thrusting and deformation of proglacial sands, and syntectonic resedimentation into low points on the sediment surface. Asynchroneity between Scottish and Irish ice‐marginal fluctuations may reflect differing responses to climate forcing during the Killard Point Stadial, or the effects of local factors such as substrate type and basal ice thermal regime. Copyright © 2004 John Wiley & Sons, Ltd.
A rock avalanche deposit in Burtness Comb, Lake District, northwest England
Authors: Clark Richard , Wilson Peter 
Published: September 2004

AbstractA large tongue‐shaped accumulation of coarse rock debris in Burtness Comb, Lake District, northwest England, previously regarded as a glacial moraine or relict rock glacier, has been examined and is reinterpreted as the product of rock‐slope failure. The debris tongue has morphological similarities with landforms produced by rock avalanches. This is the first rock avalanche deposit to be reported from the Lake District. Schmidt hammer R‐values and morphological contrasts between the upper and lower parts of the debris imply that two stages of slope failure and downslope debris streaming occurred. In the absence of evidence for a Loch Lomond Stade (c. 12.9–11.5 cal. ka BP) glacier in Burtness Comb, the debris may have accumulated at any time since removal of the Dimlington Stade ice cover (c. 16.8 cal. ka BP) and is regarded as a form of paraglacial landscape response to the effects of glaciation. Copyright © 2004 John Wiley & Sons, Ltd.