bluuebunny/crossref_metadata_2025_split huggingface dataset:
An inviscid regularization for the surface quasi‐geostrophic equation
Authors: Khouider Boualem , Titi Edriss S. 
Published: August 2007

AbstractInspired by recent developments in Berdina‐like models for turbulence, we propose an inviscid regularization for the surface quasi‐geostrophic (SQG) equations. We are particularly interested in the celebrated question of blowup in finite time of the solution gradient of the SQG equations. The new regularization yields a necessary and sufficient condition, satisfied by the regularized solution, when a regularization parameter α tends to 0 for the solution of the original SQG equations to develop a singularity in finite time. As opposed to the commonly used viscous regularization, the inviscid equations derived here conserve a modified energy. Therefore, the new regularization provides an attractive numerical procedure for finite‐time blowup testing. In particular, we prove that, if the initial condition is smooth, then the regularized solution remains as smooth as the initial data for all times. © 2007 Wiley Periodicals, Inc.
On the initial‐boundary value problem of the incompressible viscoelastic fluid system
Authors: Lin Fanghua , Zhang Ping 
Published: August 2007

AbstractIn this paper, we shall establish the local well‐posedness of the initial‐boundary value problem of the viscoelastic fluid system of the Oldroyd model. We shall also prove that the local solutions can be extended globally and that the global solutions decay exponentially fast as time goes to infinity provided that the initial data are sufficiently close to the equilibrium state. © 2007 Wiley Periodicals, Inc.
gLite Job Provenance—a job‐centric view
Authors: Křenek Aleš , Sitera Jiří , Matyska Luděk , Dvořák František , Mulač Miloš , Ruda Miroslav , Salvet Zdeněk 
Published: August 2007

AbstractJob Provenance (JP), part of the gLite Grid middleware, is a service that keeps long‐term trace on completed computations for further reference. It is a job‐centric service, keeping records about job life cycle, its environment, inputs/outputs, user parameters, and annotations. During the first provenance challenge, we explored the relation between a specific job‐centric Grid‐oriented provenance and a more general data provenance approach. The challenge represents a use case which emphasizes fields that were not priorities in the original JP design. However, we proved that the design is sufficiently general to cope with this mode of use. We also identified several areas where it is feasible to extend the current implementation. Copyright © 2007 John Wiley & Sons, Ltd.
Structural Integration of Tellurium Oxide into Mixed‐Network‐Former Glasses: Connectivity Distribution in the System NaPO3–TeO2
Authors: Rinke Matthias T. , Zhang Long , Eckert Hellmut 
Published: August 2007

AbstractSodium phosphate tellurite glasses in the system (NaPO3)x(TeO2)1−x were prepared and structurally characterized by thermal analysis, vibrational spectroscopy, X‐ray photoelectron spectroscopy (XPS) and a variety of complementary solid‐state nuclear magnetic resonance (NMR) techniques. Unlike the situation in other mixed‐network‐former glasses, the interaction between the two network formers tellurium oxide and phosphorus oxide produces no new structural units, and no sharing of the network modifier Na2O takes place. The glass structure can be regarded as a network of interlinked metaphosphate‐type P(2) tetrahedral and TeO4/2 antiprismatic units. The combined interpretation of the O 1s XPS data and the 31P solid‐state NMR spectra presents clear quantitative evidence for a nonstatistical connectivity distribution. Rather, the formation of homoatomic POP and TeOTe linkages is favored over mixed POTe connectivities. As a consequence of this chemical segregation effect, the spatial sodium distribution is not random, as also indicated by a detailed analysis of 31P/23Na rotational echo double‐resonance (REDOR) experiments.
Incompleteness of bifurcation diagram in predicting the behaviour of Ćuk converter in discontinuous conduction mode
Authors: Basak Biswarup , Parui Sukanya 
Published: August 2007

AbstractThe bifurcation phenomena have been studied in current mode‐controlled Ćuk converter considering continuous conduction as well as discontinuous conduction mode of operation. Some peculiarities have been observed in discontinuous conduction mode, which indicate some incompleteness of the bifurcation diagrams in providing details of the system behaviour. Copyright © 2007 John Wiley & Sons, Ltd.
Diphthalocyaninatolanthanum as a New Phthalocyaninato‐Dianion Donor for the Synthesis of Heteroleptic Triple‐Decker Rare Earth Element Crown‐Phthalocyaninato Complexes
Authors: Martynov Alexander G. , Zubareva Olga V. , Gorbunova Yulia G. , Sakharov Sergey G. , Nefedov Sergey E. , Dolgushin Fedor M. , Tsivadze Aslan Yu. 
Published: August 2007

AbstractA novel synthetic approach towards heteroleptic triple‐decker crown‐phthalocyaninato complexes [(15C5)4Pc]M[(15C5)4Pc]M(Pc) and (Pc)M[(15C5)4Pc]M(Pc) [where (15C5)4Pc2– = 2,3,9,10,16,17,24,25‐tetrakis(15‐crown‐5)phthalocyaninato dianion; Pc2– = phthalocyaninato dianion; M = Sm, Tb, Dy, Tm and Y] has been developed. It utilises the application of diphthalocyaninatolanthanum, La(Pc)2, as a new source of the phthalocyaninato dianion instead of well known Li2(Pc). In contrast to the highly hygroscopic Li2(Pc), La(Pc)2 is quite air‐stable and its use allowed a significant decrease in reaction times. All the synthesised complexes were characterised by UV/Vis and 1H NMR spectroscopy as well as MALDI TOF mass spectrometry. The X‐ray structure of heteroleptic triple‐decker crown‐phthalocyaninato (Pc)Sm[(15C5)4Pc]Sm(Pc) was determined. These new heteroleptic phthalocyaninato complexes are interesting because of their potential as components in new supramolecular materials. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Size‐Controlled Water‐Soluble Ag Nanoparticles
Authors: Domínguez‐Vera José M. , Gálvez Natividad , Sánchez Purificación , Mota Antonio J. , Trasobares Susana , Hernández Juan C. , Calvino Jose J. 
Published: August 2007

AbstractAg nanoparticles of two different sizes (1 and 4 nm) were prepared within an apoferritin cavity by using an Ag+‐loaded apoferritin as a nanoconfined environment for their construction. The initial amount of Ag+ ions injected in the apoferritin cavity dictates the size of the final Ag particles. The protein shell prevents bulk aggregation of the metal particles, which renders them water soluble and extremely stable.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Remarkable Functions of Long‐Chain Alkyl Groups in Halogen‐Bridged Nickel(III) Nanowire Complexes
Authors: Ohtsu Hideki , Takaishi Shinya , Imamura Keita , Ishii Ayumi , Tanaka Koji , Hasegawa Miki , Yamashita Masahiro 
Published: August 2007

AbstractThe long‐chain alkyl groups of new bidentate ligands make it possible to generate nickel MX–chain complexes exhibiting the shortest NiIII–NiIII distance among all MX–chain compounds reported. Dissolution in organic solvents occurs without dissociation of the MX–chain units, and the successful fabrication of thin films is reported. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
In Pursuit ofcis,cis,cis‐Cyclonona‐2,5,8‐triene‐1,4,7‐trione – An Adventure in Medium‐Sized Ring Chemistry
Authors: Pleschke Axel , Geier Jens , Keller Manfred , Wörth Jürgen , Knothe Lothar , Prinzbach Horst 
Published: August 2007

AbstractAttempts to synthesize the long soughtafter tris‐π‐homobenzenecis,cis,cis‐2,5,8‐cyclononatriene‐1,4,7‐trione, via the newly prepared cyclononane‐1,4,7‐trione (C9H6O3), through base‐catalysed threefold HBr elimination from an efficiently prepared and stereochemically uniform tribromo derivative, failed due to typical medium‐ring complications, transannular reactions and an exceptional ease of polymerization. In the cations generated in the vapour phase through electron‐impact ionization (MS), the threefold elimination of (H)Br, competing with the elimination of CO, led to C9H7O3+ions, whereas the impressively neat anionic three‐step fragmentation pathway resulted in C9H6O3–ion(s). Whilst the compositions of these bromine‐free ions, which were in part computationally approached {B3LYP/6‐31+G(d,p)}, and their assignments appeared compatible with the protonated and anionic target molecules, their true natures remain open. X‐ray structural analyses for several (bridged) nine‐membered ring compounds are provided. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Organocatalytic Asymmetric Mannich Reactions: New Methodology, Catalyst Design, and Synthetic Applications
Authors: Ting Amal , Schaus Scott E. 
Published: August 2007

AbstractThe direct, asymmetric Mannich reaction catalyzed by small organic molecules offers a facile route to optically active α‐ or β‐amino acid derivatives and 1,2‐ and γ‐amino alcohols. One‐pot reactions of unmodified carbonyl donors with preformed or in situ generated imines can be stereochemically controlled with Organic catalysts such as proline, chiral pyrrolidines, chiral Brønsted acids, and Cinchona alkaloids. The generated Mannich adducts can be further functionalized towards a variety of bioactive molecules. In this Microreview, recent contributions are discussed to present the methodology and synthetic advantages achieved so far in the asymmetric Mannich reaction. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Redox Behavior of Anthocyanins Present in Vitis vinifera L.
Authors: Janeiro Patricia , Brett Ana Maria Oliveira 
Published: August 2007

AbstractVoltammetric techniques were employed to study the electrochemical behavior of several anthocyanins. The redox behavior of anthocyanins with the same basic structure, the influence of glycosylation on the redox behavior of anthocyanins derived from different anthocyanidins, and the influence of methoxylation were investigated. The anthocyanins used in this study were malvidin‐3‐O‐glucoside chloride, malvidin‐3,5‐di‐O‐glucoside chloride, cyanidin‐3‐O‐glucoside chloride, cyanidin‐3,5‐di‐O‐glucoside chloride, peonidin‐3‐O‐glucoside chloride, delphinidin‐3‐O‐glucoside chloride and the anthocyanidin petunidin chloride, all of them present in Vitis vinifera L. All hydroxyl groups of the anthocyanins can be electrochemically oxidized and the anthocyanins studied revealed a complex and pH dependent oxidation process, with the occurrence of adsorption and of oxidation products blocking the electrode surface.
Electrochemical Genoassay Design for Allele‐Specific Detection of Toll‐Like Receptor‐2 Gene Polymorphism
Authors: Kara Pinar , Cavdar Seda , Berdeli Afig , Ozsoz Mehmet 
Published: August 2007

AbstractAn allele‐specific voltammetric genoassay for the detection of allele‐specific toll‐like receptor‐2 gene arg753gln polymorphism (TLR‐2) from polymerase chain reaction (PCR) amplified real samples was described in this study. Meldola blue (MDB), an intercalator molecule, was used as hybridization label. The wild‐type and mutant type oligonucleotide probes were immobilized onto disposable graphite electrode surfaces by covalent attachment method. The extent of hybridization between probe and target sequences was determined by using differential pulse voltammetry (DPV). As a result of the interaction between MDB and DNA at electrode surface, the MDB signal observed from probe sequence before hybridization and after hybridization with MM sequence is lower than that observed after hybridization with complementary sequence. The differences between the MDB reduction peaks obtained from probe modified, hybrid modified and MM modified electrode were used to detect TLR‐2 from PCR amplified real samples. The discrimination of homozygous and heterozygous alleles was also established by comparing the peak currents of MDB reduction signals. Numerous factors affecting the target hybridization and indicator binding reactions are optimized to maximize the sensitivity.
Chitosan Incorporating Cetyltrimethylammonium Bromide Modified Glassy Carbon Electrode for Simultaneous Determination of Ascorbic Acid and Dopamine
Authors: Zou Xuelian , Luo Liqiang , Ding Yaping , Wu Qingsheng 
Published: August 2007

AbstractSimultaneous determination of a neurotransmitter, dopamine (DA), and ascorbic acid (AA) is achieved at neutral pH on a chitosan incorporating cetyltrimethylammonium bromide (CTAB) modified glassy carbon (GC) electrode. Differential pulse voltammetry (DPV) technique was used to investigate the electrochemical response of DA and AA at a glassy carbon electrode modified with chitosan incorporating CTAB. An optimum 6.0 mmol L−1 of CTAB together with 0.5 wt% of chitosan was used to improve the resolution and the determination sensitivity. In 0.1 mol L−1 aqueous phosphate buffer solution of pH 6.8, the chitosan‐CTAB modified electrode showed a good electrocatalytic response towards DA and AA. The anodic peak potential of DA shifted positively, while that of AA shifted negatively. Thus, the difference of the anodic peaks of DA and AA reached 0.23 V, which was enough to separate the two anodic peaks very well. The presented method herein could be applied to the direct simultaneous determination of DA and AA without prior treatment. The anodic peak currents (Ipa) of DPV are proportional to DA in the concentration range of 8 μM to 1000 μM, to that of AA 10 μM to 2000 μM, with correlation coefficients of 0.9930 and 0.9945, respectively. The linear range is much wider than previously reported.
Electrochemical Biosensors for Pollutants in the Environment
Authors: Badihi‐Mossberg Michal , Buchner Virginia , Rishpon Judith 
Published: August 2007

AbstractThis article reviews recent advances in electrochemical biosensing and detection of environmental pollutants. Electrochemical biosensors offer precision, sensitivity, rapidity, and ease of operation for on‐site environmental analysis. An electrochemical biosensor is an analytical device in which a specific biological recognition element (bioreceptor) is integrated within or intimately associated with an electrode (transducer) that converts the recognition event to a measurable electrical signal for the purpose of detecting a target compound (analyte) in solution. This approach not only provides the means for on‐site analysis but also removes the time delay and sample alteration that can occur during transport to a centralized laboratory. We first address the basic principles of merging of electrochemistry and biology into a biosensing system, and then we discuss various environmental monitoring strategies involving this technology.
Identification of Earth Pigments by Applying Hierarchical Cluster Analysis to Solid State Voltammetry. Application to Severely Damaged Frescoes
Authors: Doménech Antonio , Doménech‐Carbó María Teresa , Edwards Howell G. M. 
Published: August 2007

AbstractMultivariate chemometric methods are applied for identifying earth pigments from square‐wave voltammetric measurements performed at pigment‐modified paraffin‐impregnated graphite electrodes allowing for a separation between hematite‐based earths, French ochres, Spanish ochres, siennas, umbers and green earths. This methodology is applied to the identification of the pigments in samples from the ceiling frescoes of Antonio Palomino (dated 1707) in the vaulted nave of the Sant Joan del Mercat church in Valencia (Spain). These frescoes suffered considerable damage by fire during the Spanish Civil War in 1936, resulting in severe chemical and chromatic alterations. Electrochemical data, supported by scanning electron microscopy/energy dispersive X‐ray microanalysis and Raman spectroscopy, indicate that thermal stress induced the transformation of goethite‐based yellow ochres into hematite and magnetite.
An Ionic‐Liquid Based Probe for the Sequential Preconcentration from Headspace and Direct Voltammetric Detection of Phenols in Wastewaters
Authors: Toniolo Rosanna , Pizzariello Andrea , Susmel Sabina , Dossi Nicolò , Doherty Andrew P. , Bontempelli Gino 
Published: August 2007

AbstractA conveniently assembled probe is here proposed for the electrochemical detection of the phenol index (total volatile phenols) in wastewaters, which exploits some advantageous properties of ionic liquids (ILs), such as their negligible vapor pressure, good electrical conductivity and ability to dissolve a wide range of organic and inorganic compounds. It consists of three Pt wires piercing through a Teflon rod, whose exposed end is coated with an adhesive film of ionic liquid which assured the necessary ionic conductivity between the electrodes while displaying concomitantly good solvent properties. The electrode assembly was exposed to the headspace in equilibrium with wastewater samples for controlled times, until a convenient preconcentration of volatile phenols was achieved. At the end of this step, voltammetric detection was directly performed in situ. The performance of this device was assayed in both phenol synthetic samples and in real wastewaters, after that the preconcentration step was optimized with regard to the effect of pH of the sample, preconcentration time, sample and probe temperature and nature of IL. Voltammetric responses characterized by good repeatability (±4%) were recorded, whose height and area depended linearly on the phenol concentration over a wide range (ca. 3 orders of magnitude). The detection limit, estimated for a signal‐to‐noise ratio of 3 (2 μM at 20 °C and 0.2 μM at 80 °C), was lower than the limit set by the European Community for phenols in wastewaters (ca. 5 μM). The results found in real samples were in acceptable agreement with those obtained by the 4‐aminoantipyrine colorimetric approach which is recommended as the standard method.
Relationship between drought and solar irradiation variables
Authors: Sirdas Sevinc , Sahin Ahmet Duran 
Published: August 2007

AbstractDrought prediction for in many regions of the world has critical importance for strategic planning agriculture and water management. The occurrence of droughts cannot be predicted with certainty and thus must be treated as random variables. It is the main purpose of this paper to develop a new concept of drought features assessments based on triple drought related hydrometeorological and meteorological variables, namely, rainfall, solar irradiation and sunshine duration. Equal standard rainfall lines are drawn as a map with two reference variables as solar irradiation and sunshine duration. These are referred to as the triple graphical method (TGM) approach. It furnishes rich features of drought behaviour variation based on the rainfall, solar irradiation and sunshine duration. This analysis and the solar irradiation estimation method are applied to seven climatologically different stations in the Republic of Turkey for the monthly data period 1982–1991. The linear relations between drought and the variables of the Angström equation are found between 55% and 94% without Trabzon. Drought and Angström equation parameters are estimated by the proposed methodology. Relations between monthly drought and Angström equation variables are presented by the triple solar‐drought graphical method. TGM provides information about the drought occurrences for different combinations of solar irradiation and sunshine duration. TGM graphs help to identify not only precipitation surplus (wet spells) or deficits (dry spells droughts) but also their variations with two more meteorological variables as solar irradiation and sunshine duration. Copyright © 2007 John Wiley & Sons, Ltd.
The cold regions hydrological model: a platform for basing process representation and model structure on physical evidence
Authors: Pomeroy J. W. , Gray D. M. , Brown T. , Hedstrom N. R. , Quinton W. L. , Granger R. J. , Carey S. K. 
Published: August 2007

AbstractAfter a programme of integrated field and modelling research, hydrological processes of considerable uncertainty such as snow redistribution by wind, snow interception, sublimation, snowmelt, infiltration into frozen soils, hillslope water movement over permafrost, actual evaporation, and radiation exchange to complex surfaces have been described using physically based algorithms. The cold regions hydrological model (CRHM) platform, a flexible object‐oriented modelling system was devised to incorporate these algorithms and others and to connect them for purposes of simulating the cold regions hydrological cycle over small to medium sized basins. Landscape elements in CRHM can be linked episodically in process‐specific cascades via blowing snow transport, overland flow, organic layer subsurface flow, mineral interflow, groundwater flow, and streamflow. CRHM has a simple user interface but no provision for calibration; parameters and model structure are selected based on the understanding of the hydrological system; as such the model can be used both for prediction and for diagnosis of the adequacy of hydrological understanding. The model is described and demonstrated in basins from the semi‐arid prairie to boreal forest, mountain and muskeg regions of Canada where traditional hydrological models have great difficulty in describing hydrological phenomena. Some success is shown in simulating various elements of the hydrological cycle without calibration; this is encouraging for predicting hydrology in ungauged basins. Copyright © 2007 John Wiley & Sons, Ltd.
Modelling enhanced infiltration of snowmelt ions into frozen soil
Authors: Lilbæk Gro , Pomeroy John W. 
Published: August 2007

AbstractA model is proposed in which the cumulative load of an ion infiltrating into frozen unsaturated soil can be estimated as a function of meltwater ion concentration and infiltration rate. Assumptions of the model are that the meltwater solution released to the soil surface is conservative, fully mixed within each time step, and that mass and energy are conserved. Infiltration and meltwater concentration are estimated using relationships developed by Gray and Stein respectively. The model suggests that the relationship between ion concentration and volume of infiltration is non‐linear with a positive covariance. Infiltration of snowmelt ions is therefore a function of the products of the mean concentration in the meltwater and the cumulative volume of water that infiltrates, plus the covariance between instantaneous values of ion concentration and infiltration rate. This covariance effect is termed enhanced infiltration. Meteorological observations and soil parameters from four sites in western Canada were used to assess the sensitivity of the model to conditions at a prairie site, a boreal forest site, a mountain forest site, and a shrub tundra site. Model results showed the greatest cumulative infiltration of ion load for the Prairie site; the general ranking was Prairie > Mountain Forest > Boreal Forest > Tundra. However, the greatest impact of enhanced infiltration was found for the Tundra site. At this site, enhanced infiltration caused up to 50% more ion load to infiltrate within the initial third of the melt period compared to infiltration estimates not accounting for this effect. Over the whole melt period, enhanced infiltration caused 55–160% more ion load to infiltrate than estimates based solely on the mean depth of infiltration and ion concentration. Sensitivity analysis showed that enhanced infiltration varies most strongly with initial snow water equivalent, average melt rate over the whole melt period, and snowpack ion elution concentration factor (CF). Copyright © 2007 John Wiley & Sons, Ltd.