bluuebunny/crossref_metadata_2025_split huggingface dataset:
Experience‐dependent plasticity in the mushroom bodies of the solitary bee Osmia lignaria (Megachilidae)
Authors: Withers Ginger S. , Day Nancy F. , Talbot Emily F. , Dobson Heidi E.M. , Wallace Christopher S. 
Published: October 2007

AbstractAll members of the solitary bee species Osmia lignaria (the orchard bee) forage upon emergence from their natal nest cell. Conversely, in the honey bee, days‐to‐weeks of socially regulated behavioral development precede the onset of foraging. The social honey bee's behavioral transition to foraging is accompanied by neuroanatomical changes in the mushroom bodies, a region of the insect brain implicated in learning. If these changes were general adaptations to foraging, they should also occur in the solitary orchard bee. Using unbiased stereological methods, we estimated the volume of the major compartments of the mushroom bodies, the neuropil and Kenyon cell body region, in adult orchard bees. We compared the mushroom bodies of recently emerged bees with mature bees that had extensive foraging experience. To separate effects of general maturation from field foraging, some orchard bees were confined to a cage indoors. The mushroom body neuropil of experienced field foragers was significantly greater than that of both recently emerged and mature caged orchard bees, suggesting that, like the honey bee, this increase is driven by outdoor foraging experience. Unlike the honey bee, where increases in the ratio of neuropil to Kenyon cell region occur in the worker after emerging from the hive cell, the orchard bee emerged from the natal nest cell with a ratio that did not change with maturation and was comparable to honey‐bee foragers. These results suggest that a common developmental endpoint may be reached via different development paths in social and solitary species of foraging bees. © 2007 Wiley Periodicals, Inc. Develop Neurobiol, 2008
Relevant antibody subsets against MOG recognize conformational epitopes exclusively exposed in solid‐phase ELISA
Authors: Menge Til , von Büdingen Hans‐Christian , Lalive Patrice H , Genain Claude P 
Published: October 2007

AbstractA pathogenic role for circulating anti‐myelin antibodies is difficult to establish in multiple sclerosis (MS). Here, we unravel a broad heterogeneity within the anti‐myelin oligodendrocyte glycoprotein (MOG) antibodies in humans and non‐human primates, and demonstrate that detection of important epitopes of MOG within the pathogenic repertoire is exclusively dependent on presentation on a solid‐phase MOG conformer. Results of ELISA and those of a liquid‐phase assay were compared using a MOG protein with identical sequence but different conformations. We tested sera from 50 human subjects, plasma of Callithrix jacchus marmosets known to contain antibodies reactive to either conformational or linearized MOG, and monoclonal, conformation‐dependent anti‐MOG antibodies. We have found no antibody reactivity against the soluble MOG conformer in human serum, and show that this lack of detection is not due to technical artifacts. Rather, dominant epitopes of MOG are not displayed in soluble phase, as shown by a complete lack of binding of conformation‐dependent mAb. In MP4‐immune marmosets that exhibit demyelinating pathology due to spreading of antibody determinants to myelin‐embedded MOG, only ELISA can detect pathogenic circulating anti‐MOG antibodies. Thus, the accurate detection of important subsets of pathogenic anti‐MOG antibodies requires methods in which MOG is displayed similarly to its natural conformation in myelin.
Tetranuclear Complexes of PdII with Tridentate [C,N,O] and [O,N,O] Ligands: Synthesis, Reactivity and Structural Isomerism
Authors: Fernández Jesús J. , Fernández Alberto , Vázquez‐García Digna , López‐Torres Margarita , Suárez Antonio , Gómez‐Blanco Nina , Vila José M. 
Published: October 2007

AbstractTreatment of the Schiff base ligand 2,3,4‐(MeO)3C6H2C(H)=N[2‐(OH)‐5‐tBuC6H3] (a) with palladium(II) acetate in toluene gave the cyclometallated complex [Pd{2,3,4‐(MeO)3C6HC(H)=N(2‐O‐5‐tBuC6H3)}]4 (1a) with the tridentate ligand [C,N,O]. The complex showed a tetranuclear arrangement of the cyclometallated monomers with a P4O4 core. Reaction of 2,6‐(Me)2C6H3C(H)=N[2‐(OH)C6H4] (b) and 2,5‐(Me)2C6H3C(H)=N[2‐(OH)C6H4] (c) with palladium(II) acetate under similar conditions yielded the tetranuclear complexes [Pd{6‐Me‐2‐CH2C6H3C(H)=N(2‐OC6H4)}]4 (1b) and [Pd{5‐Me‐2‐CH2C6H3C(H)=N(2‐OC6H4)}]4 (1c), respectively, in which the tridentate [C,N,O] ligand is bound through the aliphatic methyl carbon. Treatment of 2,4‐(Me)2C6H3C(H)=N[2‐(OH)C6H4] (d) with palladium(II) acetate yielded a mixture of isomers, [Pd{4‐Me‐2‐CH2C6H3C(H)=N(2‐OC6H4)}]n[Pd{2,4‐(Me)2C6H2C(H)=N(2‐OC6H4)}]4–n (n = 0–4), also bearing a tetranuclear structure. However, thetetramer was assembled by two types of mononuclear Pd(ligand) building blocks: the ligand is coordinated through the aliphatic methyl carbon in one and through the aromatic ortho carbon in the other. The crystal structure of one such isomer confirmed the spectroscopic data. Treatment of 2‐(OH)‐4,6‐(MeO)2C6H2C(H)=N[2‐(OH)C6H4] (e) and 2‐(OH)C6H4C(H)=N[2‐(OH)C6H4] (f) with palladium(II) acetate yielded the tetranuclear complexes [Pd{2‐O‐4,6‐(MeO)2C6H2C(H)=N(2‐OC6H4)}]4 (1e) and [Pd{2‐OC6H4C(H)=N(2‐OC6H4)}]4 (1f), respectively, after double deprotonation of the ligand, which coordinates to the metal through the two phenoxy oxygen atoms and the imine nitrogen atom in these complexes. Reaction of compounds 1a–1f with tertiary phosphanes in acetone gave mono‐ and dinuclear complexes, after cleavage of the tetranuclear structure. In these complexes, the tertiary phosphane is bonded trans to the nitrogen atom. The crystal structures for 1a, 1c, 1e, 1d/1d′ are reported; they show the characteristic Pd4O4 core.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Reductive Nitrosation of Peptides Ligated to High‐Valent Metal Cations
Authors: Shamir Dror , Zilbermann Israel , Maimon Eric , Gellerman Gary , Cohen Haim , Meyerstein Dan 
Published: October 2007

AbstractNO reacts with MIII–(glycylglycylglycine), M = Fe; Ni and Cu, to form the terminal N‐nitrosated peptide complex. This reaction proceeds by a radical mechanism. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
From Central to Axial to Central Chirality: Enantioselective Construction of the trans‐4,5,9,10‐Tetrahydroxy‐9,10‐dihydrophenanthrene System
Authors: Stavrakov Georgi , Keller Manfred , Breit Bernhard 
Published: October 2007

AbstractEnantioselective synthesis of the core trans‐4,5,9,10‐tetrahydroxy‐9,10‐dihydrophenanthrene parent system of the antibiotics benanimicin, pradimicin and FD 594 has been accomplished. The synthesis employs a chiral tether approach and makes use of efficient central to axial to central chirality transfer. Key to success was an “imine‐directed” atropdiastereoselective Ullmann coupling under mild reaction conditions. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Electrocatalytic Reduction of Nitrite Ion on a Toluidine Blue Sol‐Gel Thin Film Electrode Derived from 3‐Aminopropyl Trimethoxy Silane
Authors: Thenmozhi K. , Narayanan S. Sriman 
Published: October 2007

AbstractAn organically modified sol‐gel electrode using 3‐aminopropyltrimethoxy silane for covalent immobilization of a redox mediator namely toluidine blue has been reported. Cyclic voltammetric characterization of the modified electrode in the potential range of 0.2 V to −0.6 V exhibited stable voltammetric behavior in aqueous supporting electrolyte with a formal potential of −0.265 V vs. SCE, corresponding to immobilized toluidine blue. The electrocatalytic activity of the modified electrode when tested towards nitrite ion exhibited a favorable response with the electrocatalytic reduction of nitrite occurring at a reduced potential of −0.34 V. A good linear working range from 2.94×10−6 M to 2.11×10−3 M with a detection limit of 1.76×10−6 M and quantification limit of 5.87×10−6 M was obtained for nitrite determination. The stable and quick response (4 s) of the modified electrode towards nitrite under hydrodynamic conditions shows the feasibility of using the present sensor in flow systems. Significant improvements in the operational stability by overcoming the leachability problem and repeatability with a relative standard deviation of 1.8% of the TB thin film sensor have been obtained by the strategy of immobilization of the mediator in the sol‐gel matrix.
Determination of Thallium in a Flow System by Anodic Stripping Voltammetry at a Bismuth Film Electrode
Authors: Korolczuk Mieczyslaw , Surmacz Weronika , Tyszczuk Katarzyna 
Published: October 2007

AbstractA procedure for trace thallium determination by anodic stripping voltammetry at a bismuth film electrode is presented. Measurements were performed in a flow system. The calibration graph was linear from 2×10−9 to 3×10−8 mol L−1 for an accumulation time of 300 s. A detection limit for Tl+ following deposition time of 300 s was 6×10−10 mol L−1. The relative standard deviation at Tl+ concentration 2×10−8 mol L−1 was 3.9%. For determination of thallium in complex matrices the procedure for elimination of interferences from foreign ions exploiting anion exchange resin was proposed. The procedure proposed was validated by analysis of rain water certified reference material.
Lab‐on‐a‐Chip Biosensor for Glucose Based on a Packed Immobilized Enzyme Reactor
Authors: Blanes Lucas , Mora Maria F. , do Lago Claudimir L. , Ayon Arturo , García Carlos D. 
Published: October 2007

AbstractIn this work, the development of a packed immobilized enzyme reactor (IMER) and its integration to a capillary electrophoresis microchip is described. The present microchip design differs from others, in the fact that the same design could be used with or without the particles and, just by changing the material used to pack the IMER, different analytes can be detected. The applied procedure involves the separation of the target analyte by capillary electrophoresis (CE), which is then coupled to a post‐column IMER that produces H2O2. The H2O2 produced is finally detected downstream at the surface of a working electrode. Glucose was detected above 100 μM by packing particles modified with glucose oxidase at the end of the separation channel. The analytical performance of the microchip‐CE has been demonstrated by performing the separation and detection of glucose and noradrenaline. Additions of fructose showed no effect on either the peak position or the peak magnitude of glucose. The microchip‐CE‐IMER was also used to quantify glucose in carbonated beverages with good agreement with other reports.
Voltammetric Behavior of the Alizarin Red S Interaction with DNA and Damage to DNA
Authors: Yang Zhou‐Sheng , Zhang Da‐Peng , Long Hai‐Yan , Zhao Guang‐Chao 
Published: October 2007

AbstractThe electrochemical behavior and the interaction of alizarin red S (ARS) with calf thymus DNA was investigated on a bare glassy carbon electrode (GCE) and DNA modified GCE (DNA/GCE), respectively. ARS showed a pair of redox peaks at −0.445 V and −0.414 V on a bare GCE. On addition of DNA into the ARS solution, the peak current of ARS decreased and the peak potential positively shifted, but without new redox peaks appeared. The ARS reduction peak current increased with immersion time on a DNA/GCE. The results showed that ARS could interact with DNA molecules by intercalative binding mode. The equilibrium constant, binding number and the ratio of binding constant for oxidized and reduced ARS forms were obtained. The DNA damage was directly detected by appearance of guanosine and adenosine bases oxidation signal. The influence of experimental conditions on DNA damage extent was discussed in detail.
Electrochemical Behavior and Multilayer Assembly Films with Fine Functional Activities of the Sandwich‐Type Polyoxometallate [Sb2W20Fe2O70(H2O)6]8−
Authors: Bi Li‐Hua , McCormac Timothy , Beloshapkin Sergey , Dempsey Eithne 
Published: October 2007

AbstractThe iron‐substituted sandwich‐type polyoxometalate (POM), comprised of the main group element Sb(III) as the central heteroatom, [Sb2W20Fe2O70(H2O)6]8− (Sb2W20Fe2), is one of the Krebs‐type derivatives. For the first time, the POMs' redox electrochemistry has been elucidated under acidic conditions employing cyclic voltammetry. It exhibited what is believed to be a bielectronic redox couple associated with the two Fe(III) centers followed by four‐electron and two‐electron redox processes, respectively, with these being attributed to redox processes of the tungsten‐oxo framework. The oxidized form of this POM was found to be stable from pH 1.5 to pH 6. Release of the iron centers from the complex, namely demetallization, was observed upon reduction of the Fe(III) sites at room temperature, with an influence of the solution pH being observed. Through the technique of layer‐by‐layer (LBL) assembly, the POM was successfully immobilized on both quartz and glassy carbon electrode (GCE) surfaces by alternate deposition with the polyelectrolyte poly(diallydimethylammonium chloride) (PDDA). Thus‐prepared multilayer films have been characterized by cyclic voltammetry (CV), UV‐vis spectroscopy (UV‐vis) and XPS. The electrocatalytic activities of the multilayer films containing Sb2W20Fe2 have been investigated towards the reduction of NO3− and IO3−. With an increase in the number of Sb2W20Fe2 monolayers within the assembly, the catalytic current towards the reduction of IO3− was enhanced.
High‐order ENO and WENO schemes for unstructured grids
Authors: Wolf W. R. , Azevedo J. L. F. 
Published: October 2007

AbstractThis work describes the implementation and analysis of high‐order accurate schemes applied to high‐speed flows on unstructured grids. The class of essentially non‐oscillatory schemes (ENO), that includes weighted ENO schemes (WENO), is discussed in the paper with regard to the implementation of third‐ and fourth‐order accurate methods. The entire reconstruction process of ENO and WENO schemes is described with emphasis on the stencil selection algorithms. The stencils can be composed by control volumes with any number of edges, e.g. triangles, quadrilaterals and hybrid meshes. In the paper, ENO and WENO schemes are implemented for the solution of the dimensionless, 2‐D Euler equations in a cell centred finite volume context. High‐order flux integration is achieved using Gaussian quadratures. An approximate Riemann solver is used to evaluate the fluxes on the interfaces of the control volumes and a TVD Runge–Kutta scheme provides the time integration of the equations. Such a coupling of all these numerical tools, together with the high‐order interpolation of primitive variables provided by ENO and WENO schemes, leads to the desired order of accuracy expected in the solutions. An adaptive mesh refinement technique provides better resolution in regions with strong flowfield gradients. Results for high‐speed flow simulations are presented with the objective of assessing the implemented capability. Copyright © 2007 John Wiley & Sons, Ltd.
The possible hydrologic effects of the proposed lignite open‐cast mining in Drama lignite field, Greece
Authors: Panilas Sotiris , Petalas Christos P. , Gemitzi Alexandra 
Published: October 2007

AbstractThe present study investigates the possible hydrologic effects of the proposed lignite open‐cast mining in Drama lignite field (north Greece). Recent years have seen a rapid increase in surface mining. This activity has generated a growing concern for the potential environmental impacts associated with large scale surface mining.In order to achieve a safe mine operation and allow extraction of lignite to considerable depths, extensive dewatering by pumping will be necessary, while at the same time it is desirable to avoid presence of overpumping conditions in the broader area. Based on stratigrafic, hydrologic and hydrogeologic data, a three‐dimensional finite difference model was developed in order to simulate the dewatering process of the western part of the lignite open‐cast mine in Drama and to predict both spatially and temporally the decline of ground water level down to the lignite surface. The dewatering of the part of the aquifer which underlies the mine area will influence the hydrological conditions of the broader region. The most important anticipated effects will be the abandonment of shallow wells as well as the decrease of ground water pumping rates of deep wells. Aquifer discharge towards the ditches of the study area will cease and there will be an inversion of ground water flow from the ditches towards the underlying aquifer. Dewatering activities will probably result in minor subsidence of the nearby peat deposits of Drama Philippi marshes. Moreover, sand pumping as well as the presence of gasses is likely to cause local subsidence phenomena, mainly in the pit slopes. Copyright © 2007 John Wiley & Sons, Ltd.
Aquifer interactions with a polluted mountain river of Nicaragua
Authors: Mendoza Jose Alfredo , Ulriksen Peter , Picado Francisco , Dahlin Torleif 
Published: October 2007

AbstractThe interactions between a stream and nearby shallow aquifers were investigated in a mountain basin being polluted by mercury released during mining in central Nicaragua. Hourly data series of water levels and temperatures were analysed using cross‐correlation. Resistivity imaging was used to map the subsurface and to complement the hydrological data interpretation. The results show the complex hydrogeological conditions that characterize the region, with weathering and fractured rock as main contributors to groundwater transport. The resistivity images suggest the presence of two vertical dykes perpendicular to the stream, and zones rich in clay. The data series indicate a rapid response from the aquifers to recharge events, followed by immediate discharge on a yearly basis. Furthermore, alternating periods of stream infiltration and aquifer discharge were identified. This work demonstrates that surface water pollution is a threat to groundwater quality in the area. Copyright © 2007 John Wiley & Sons, Ltd.
Internal testing of a numerical model of hillslope–channel coupling using laboratory flume experiments
Authors: Michaelides Katerina , Wainwright John 
Published: October 2007

AbstractThe numerical model COUP2D simulates the hydrological coupling between hillslopes and the river channel during a rainfall event. In order to test the numerical model, a 1:100 scaled laboratory flume which was modified to incorporate lateral hillslope elements, was used to run a series of experiments in which hillslope angle, channel angle, hillslope discharge and channel discharge were the varying parameters. Overall, there were 18 different experimental configurations with three replicates carried out for each condition, leading to a total of 54 experiments. These conditions were then used to parameterize and run COUP2D. Internal model outputs of flow depth and flow velocity at four cross‐sections in the channel were compared to the measurements made in the physical model for the same parameter conditions. Statistical comparisons of the measured and modelled data were carried out for each experiment and across all experiments, using two goodness‐of‐fit measures—root mean square error and Nash–Sutcliffe coefficient of efficiency—in order to assess the performance of the model over an entire simulation as well as over all the simulations. The main effects on the goodness‐of‐fit measures for flow depth of each experimental variable, as well as the interactions between variables, were evaluated using statistical modelling. The results show that the model captures flow‐depth variations in response to changing channel and hillslope parameters. Statistical modelling suggests that the main effects on model error are cross‐section position, channel angle and channel discharge. Significant interactions also occur between all the channel variables and between the channel variables and hillslope discharge. The results of the testing procedure have significant implications for the consideration of different model components and for the interaction between data‐ and model evaluation. Copyright © 2007 John Wiley & Sons, Ltd.
Fog interception by non‐vascular epiphytes in tropical montane cloud forests: dependencies on gauge type and meteorological conditions
Authors: Villegas Juan Camilo , Tobón Conrado , Breshears David D. 
Published: October 2007

AbstractPrecipitation is the most fundamental input of water for terrestrial ecosystems. Most precipitation inputs are vertical, via rain, but can be horizontal, via wind‐driven rain and snow, or, in some ecosystems such as tropical montane cloud forests (TMCFs), via fog interception. Fog interception can be particularly important in ecosystems where fog is frequently present and there are seasonal periods of lower rainfall. Epiphytes in trees are a major ecological component of TMCFs and are particularly dependent on fog interception during periods of lower rainfall because they lack access to soil water. But assessing fog interception by epiphytes remains problematic because: (i) a variety of field or laboratory methods have been used, yet comparisons of interception by epiphytes versus interception by various types of fog gauge are lacking; (ii) previous studies have not accounted for potential interactions between meteorological factors. We compared fog interception by epiphytes with two kinds of commonly used fog gauges and developed relations between fog interception and meteorological variables by conducting laboratory experiments that manipulated key fog characteristics and from field measurements of fog interception by epiphytes. Fog interception measured on epiphytes was correlated with that measured from fog gauges but was more than an order of magnitude smaller than the actual measurements from fog gauges, highlighting a key measurement issue. Our laboratory measurements spanned a broad range of liquid water content (LWC) values for fog and indicate how fog interception is sensitive to an interaction between wind speed and LWC. Based on our results, considered in concert with those from other studies, we hypothesize that fog interception is constrained when LWC is low or high, and that fog interception increases with wind speed for intermediate values of LWC—a net result of deposition, impaction, and evaporation processes—until interception begins to decrease with further increases in wind speed. Copyright © 2007 John Wiley & Sons, Ltd.