bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis and Characterization of Bis(dithiolene) Tungsten(VI), ‐(V), and ‐(IV) Complexes and Their Reactivities in Coupled Electron–Proton Transfer: A New Series of Active Site Models of Tungstoenzymes
Authors: Sugimoto Hideki , Tarumizu Makoto , Miyake Hiroyuki , Tsukube Hiroshi 
Published: August 2007

AbstractNew tungsten(VI), ‐(V), and ‐(IV) complexes containing 3,6‐dichloro‐1,2‐benzenedithiolate (bdtCl2), (Et4N)2[WVIO2(bdtCl2)2] {(Et4N)2[1]}, (Et4N)[WVO(bdtCl2)2] {(Et4N)[2]}, and (Et4N)2[WIVO(bdtCl2)2] {(Et4N)2[3]} were synthesized and characterized as active site models of tungstoenzymes.(Et4N)2[1] was prepared in high yield by the reaction of WO2Cl2 with 2bdtCl2 at low temperature, and its crystal structure was determined. Isomerization between octahedral structures (Δ and Λ forms) of the tungsten center of(Bu4N)2[1] was characterized by variable‐temperature 1H NMR (VT 1H NMR) spectral analysis, which offers the first example of six‐coordinate bis(dithiolene) tungsten(VI) complexes. The isomerization of the molybdenum center of (Bu4N)2[MoVIO2(bdtCl2)2] {(Bu4N)2[4]} was similarly characterized. A comparison of their activation energies indicated that the tungsten center underwent slower isomerization than that of the molybdenum one. (Et4N)2[1] underwent an irreversible reduction at –2.1 V vs. SCE in CH3CN by a coupled electron–proton transfer (CEPT) process to yield(Et4N)2[3], while (Et4N)2[3] underwent an irreversible oxidation by a CEPT process at –0.27 V in the presence of 2 equiv. of Et4NOH in CH3CN to yield (Et4N)2[1]. (Et4N)[2] disproportionated into 0.5 equiv. of (Et4N)2[1] and 0.5 equiv. of (Et4N)2[3] when treated with 1 equiv. of Et4NOH in CH3CN.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Determination of Traces of Cobalt in Zinc Matrix by Catalytic Adsorptive Stripping Voltammetry at Bismuth Film Electrode
Authors: Korolczuk Mieczyslaw , Grabarczyk Małgorzata , Moroziewicz Aleksandra 
Published: August 2007

AbstractAn catalytic adsorptive stripping voltammetric procedure for the determination of cobalt in a zinc matrix at an in situ plated bismuth film electrode was described. The procedure exploits the enhancement effect of a cobalt peak observed in the system Co(II)–dimethylglyoxime–piperazine‐1,4‐bis(2‐ethanesulfonic acid)–cetyltrimethylammonium bromide. Using optimized conditions, in a solution containing 0.01 mol L−1 Zn(II) the calibration plot for Co(II) following accumulation time of 120 s was linear from 2×10−10 to 5×10−8 mol L−1. The detection limit (based on 3σ criterion) for Co(II) of 6×10−11 mol L−1 was achieved. The proposed procedure was applied for Co(II) determination in zinc reagent for analysis and in tap water.
The Effect of the Closely‐Spaced Working and Auxiliary Electrodes on the Performance of Electrochemical Oxygen Sensor
Authors: Wu Jian , Ye Zunzhong , Ying Yibin , Ji Feng 
Published: August 2007

AbstractIn this paper the influence of the electrochemical reaction at the auxiliary electrode of oxygen microsensors on the sensor performance was investigated. When the auxiliary electrode is closely spaced to the working electrode, the redox cycling of O2/H2O takes place in an electrochemical oxygen sensor. This cycling alters the oxygen distribution around the working electrode and therefore affects the measured cathodic current passing through the working electrode. Calibrations have to be taken out to determine the real O2/H2O cycling effects. Furthermore, this redox cycling also provides the possibility to enhance the sensitivity of the electrochemical oxygen microsensor. Experimental results indicate that the sensitivity of the oxygen sensor is enhanced 3.0 times with the on‐chip 10 μm spaced interdigitated auxiliary electrode.
Work‐related physical activity and the risk of dementia and Alzheimer's disease
Authors: Rovio Suvi , Kåreholt Ingemar , Viitanen Matti , Winblad Bengt , Tuomilehto Jaakko , Soininen Hilkka , Nissinen Aulikki , Kivipelto Miia 
Published: August 2007

AbstractBackgroundLeisure‐time physical activity has been related with a reduced risk of dementia and Alzheimer's disease (AD). The effects of occupational and commuting physical activity (physical activity at work and on the way to work) on cognitive health are still unclear. This study aimed to clarify the association between work‐related physical activity and dementia/AD.MethodsParticipants of the Cardiovascular Risk Factors, Aging, and Dementia (CAIDE) study were derived from random, population‐based samples previously studied in a survey carried out in 1972, 1977, 1982, or 1987. After an average follow‐up of 21 years, 1449 individuals (73%) aged 65 to 79 years participated in the re‐examination in 1998.ResultsNeither occupational [Odds Ratio (OR) 1.45; 95% Confidence Intervals (CI) 0.66–3.17] nor commuting physical activity (OR 0.46; 95% CI 0.10–2.17) were associated with the risk of dementia or AD after adjustments for age, sex, education, follow‐up time, locomotor symptoms, main occupation during life, income at midlife, leisure‐time physical activity, other subtype of work‐related physical activity, ApoE genotype, vascular disorders and the smoking status. There were also no interactions between work‐related physical activity and the ApoE ε4 genotype, leisure‐time physical activity or sex.ConclusionsIn this study, work‐related physical activity was not found to be sufficient to protect against dementia and AD later in life. The lack of effect might be partly due to a residual confounding. Nevertheless, physical activity during leisure‐time may be beneficial even for people who are physically active at work or when commuting. Copyright © 2007 John Wiley & Sons, Ltd.
A mass‐balance approach to estimate in‐stream processes in a large river
Authors: Teissier Samuel , Sauvage Sabine , Vervier Philippe , Garabétian Frédéric , Sánchez‐Pérez José‐Miguel 
Published: August 2007

AbstractA mass‐balance approach was used to estimate in‐stream processes related to inorganic nitrogen species (NH4+, NO2− and NO3−) in a large river characterized by highly variable hydrological conditions, the Garonne River (south‐west France). Studies were conducted in two consecutive reaches of 30 km located downstream of the Toulouse agglomeration (population 760 000, seventh order), impacted by modification of discharge regime and high nitrogen concentrations. The mass‐balance was calculated by two methods: the first is based on a variable residence time (VRT) simulated by a one‐dimensional (1‐D) hydraulic model; the second is a based on a calculation using constant residence time (CRT) evaluated according to hydrographic peaks. In the context of the study, removal of dissolved inorganic nitrogen (DIN) for a reach of 30 km is underestimated by 11% with the CRT method. In sub‐reaches, the discrepancy between the two methods led to a 50% overestimation of DIN removal in the upper reach (13 km) and a 43% underestimation in the lower reach (17 km) using the CRT method. The study highlights the importance of residence time determination when using modelling approaches in the assessment of whole stream processes in short‐duration mass‐balance for a large river under variable hydrological conditions. Copyright © 2007 John Wiley & Sons, Ltd.
An integrated framework of lake‐stream connectivity for a semi‐arid, subarctic environment
Authors: Woo Ming‐ko , Mielko Corrinne 
Published: August 2007

AbstractLake‐stream networks dominate the semi‐arid, subarctic Precambrian shield. Such a network consists of a number of lake basin elements linked to each other by surface channels. To investigate the processes causing seasonal severance of flow connection in the lake‐stream system, a chain of lakes in northern Canada was studied in 2004. Water balance shows that rapid and substantial runoff from the local basin slopes during the snowmelt period led to a rise of lake levels above their outlet elevations to generate outflow. Continued summer evaporation caused draw down of lake storage below the outflow thresholds, represented by the lake outlet elevations. Outflow ceased and the lakes became disconnected. Summer rainfall in a semi‐arid environment was insufficient to overcome storage deficit to re‐establish flow connectivity among all lakes. For the drainage system as a whole, streamflow interruption or continuity depends on the linkage of its lake‐stream sub‐units. The principle of fill and spill governs runoff generation and flow connection between the lake elements. This principle is applied to a conceptual model of flow along a chain of lakes, taking account of (1) antecedent storage in individual lakes, (2) their storage change calculated through water balance and (3) the thresholds to be exceeded for outflows to occur. Copyright © 2007 John Wiley & Sons, Ltd.
A simple heat‐conduction method for simulating the frost‐table depth in hydrological models
Authors: Hayashi Masaki , Goeller Neil , Quinton William L. , Wright Nicole 
Published: August 2007

AbstractHillslope runoff in permafrost regions covered by organic soil is strongly influenced by subsurface flow in the active layer, as well as surface flow where the active layer is very shallow. Flow rates in the organic‐rich active layer are strongly dependent on the depth to the thawing front (i.e. frost table) and the corresponding soil hydraulic conductivity at that depth. Therefore, hydrological models for permafrost terrains need to simulate the thawing of the active layer accurately. In order to simulate the downward movement of the frost table, a simple heat‐conduction model was proposed and compared to field data from a wet, organic‐covered watershed in a discontinuous permafrost region of Canada. Ground heat flux was measured simultaneously using the calorimetric, gradient, and flux‐plate methods to increase the confidence in data sets. The majority (>86%) of ground heat flux was used to melt the ice in frozen soil, and the soil temperature had a linear profile from the ground surface to the frost table when averaged over several days. Assuming a linear temperature profile, the proposed method calculates the daily rate of thawing from ground surface temperature and bulk thermal conductivity, where the latter is essentially determined by soil water content. Simulated depths to the frost table during three thaw seasons (2003–2005) matched closely with the observed data for two contrasting ground‐cover types with distinctly different thaw rates. The method can be easily implemented in hydrological models, and will provide a useful tool for simulating hillslope drainage in organic‐covered permafrost terrains, and for evaluating the effects of topography and land cover on the temporal and seasonal variability of the frost table. Copyright © 2007 John Wiley & Sons, Ltd.
Characterization of the interplay between the main factors contributing to lipoplex‐mediated transfection in cell cultures
Authors: Boktov Julia , Hirsch‐Lerner Danielle , Barenholz Yechezkel 
Published: August 2007

AbstractTransfection efficiency of lipoplex‐mediated gene delivery is multifactorial. However, the mode of interaction between the factors which affect transfection is not fully understood. To help fill this deficiency we evaluated the effect of the interplay between several variables that affect transfection efficiency in cell cultures. For this, we applied the Analysis of Variance Model with Fixed Effects and Repeated Measures to assess the data. The variables studied include: two different genes, Luc, and human growth hormone (hGH), in three different plasmids (two of which contain the luciferase (Luc) gene, but different promoter‐enhancer regions (CMV and H19) and one plasmid coding hGH with a S16 promoter); three topoisoforms of pDNA (supercoiled (SC), open circular (OC), and closed circular (CC)); three cationic lipid compositions, all based on the monocationic lipid DOTAP (100% DOTAP, DOTAP/DOPE 1 : 1, and DOTAP/cholesterol 1 : 1, all ratios are mole ratios); two DNA−/L+ charge ratios (0.2 and 0.5); and two cell lines (NIH 3T3 and MBT‐2). Our statistical analysis confirmed that the cell type, the gene used for transfection, the promoter type, the type of helper lipid, and DNA−/DOTAP+ charge ratio, all affect transfection efficiency in a statistically significant manner. The most efficient lipoplex formulation in both cell lines was that based on DOTAP (without helper lipid), having CC plasmid DNA. We suggest that for obtaining the most transfection‐efficient lipoplex one should select the best topoisoform of pDNA for each particular cell type, and complex it with cationic liposomes having optimal lipid composition. Copyright © 2007 John Wiley & Sons, Ltd.
Continuum modeling of large networks
Authors: Chong Edwin K. P. , Estep Donald , Hannig Jan 
Published: August 2007

AbstractThis paper is concerned with the modeling and simulation of extremely large networks. We derive a time‐dependent diffusion–convection partial differential equation, the solution of which captures the global characteristics of a stochastic network model. Continuum modeling provides a powerful way to deal with the number of components in large networks and opens up the use of highly sophisticated mathematical tools such as adaptive finite element methods. This, in turn, makes it possible to carry out—with reasonable computational burden even for very large systems—network performance evaluation and prototyping, network design, systematic parameter studies, and optimization of network characteristics. Copyright © 2007 John Wiley & Sons, Ltd.
Hydrometeorological analysis of northwestern Turkey with links to climate change
Authors: Aksoy Hafzullah , Unal N. Erdem , Alexandrov Vesselin , Dakova Snejana , Yoon Jaeyoung 
Published: August 2007

AbstractPrecipitation, air temperature, and streamflow data from the European part of Turkey are analysed by means of a set of tests available in the hydrometeorological literature. Structural characteristics such as randomness, jump, trend, and a best‐fit probability distribution function are determined. Concluding remarks related to the structural characteristics of hydrometeorological data state that no significant trend and jump exist in the time series, and the best‐fit probability distribution function is the gamma for the streamflow data. Climate change scenarios based on ECHAM4 as well as HadCM2 and HadCM3 global circulation models are developed for the region, and projections are made for the 21st century. Projections made by climate change scenarios signal higher air temperature and lower precipitation in the 21st century and warn for severe extremes, higher maxima and lower minima, both in time and space. Copyright © 2007 Royal Meteorological Society
Variability and trends in indices of quality‐controlled daily temperature extremes in Uruguay
Authors: Rusticucci Matilde , Renom Madeleine 
Published: August 2007

AbstractA database of daily extreme temperature was created for as many stations as possible for Uruguay, as far back as possible. This is the first attempt to gather all the different data sources together, perform a quality control and homogeneity assessment. We work with seven stations; it should be taken into account that Uruguay is a small country (around 177 000 km2) and this represents most of the available data. There are three old series with starting dates in 1930, and four that start around 1950. From this database, a set of four extreme temperature indices was constructed for the oldest five stations, warm days (TX90), cold days (TX10), warm nights (TN90) and cold nights (TN10).The index TN10 shows the largest significant negative trend for the period 1960–2002, while TN90 shows a positive but not significant trend for this period indicating a strong warming of nighttime temperature. A spectral analysis was performed using the multi taper methods (MTM) to the de‐trended annual, summer Dec–Feb (DJF) and winter Jun–Aug (JJA) indices time‐series. This analysis shows that on inter‐annual timescales, the most significant range of frequencies is from 2 to 2.5 years and from 3 to 6 years. Low frequencies of variability were detected when the MTM was applied to de‐trended smoothed annual time‐series, around the range of frequencies of 15–25 years for almost all the indices analysed. Links with global sea surface temperature (SST) were studied for two stations (Paysandu and Rocha), and it was found that the indices showed largest correlations with SST anomalies in the Pacific Ocean. We detected changes in the response of the TN10 index for Rocha station when the series was split up into two different periods (1942–1976 and 1977–2005). Copyright © 2007 Royal Meteorological Society
A Raman spectroscopic study of the uranyl carbonate rutherfordine
Authors: Frost Ray L. , Čejka Jiří 
Published: August 2007

AbstractThe molecular structure of the uranyl mineral rutherfordine has been investigated by the measurement of its Raman spectra at 298 and 77 K and complemented with infrared spectra. The infrared spectra of the (CO3)2− units in the anti‐symmetric stretching region show complexity with three sets of carbonate bands observed. This, combined with the observation of multiple bands in the (CO3)2− bending region in both Raman and IR spectra, suggests that both monodentate and bidentate (CO3)2− units are present in the structure in accordance with the X‐ray crystallographic studies. Complexity is also observed in the IR spectra of (UO2)2+ anti‐symmetric stretching region and is attributed to non‐identical UO bonds. Both Raman and infrared spectra of the rutherfordine show the presence of both water and hydroxyl units in the structure, as evidenced by IR bands at 3562 and 3465 cm−1 (OH) and 3343, 3185 and 2980 cm−1 (H2O). Raman spectra show the presence of four sharp bands at 3511, 3460, 3329 and 3151 cm−1. Copyright © 2007 John Wiley & Sons, Ltd.
Raman spectroscopic studies of the corrosion of model iron electrodes in sodium chloride solution
Authors: Larroumet Damien , Greenfield David , Akid Robert , Yarwood Jack 
Published: August 2007

AbstractWe have explored the un‐enhanced Raman spectra of both single and twin electrodes in 3.5% NaCl solution (at ambient temperatures) over a range of applied potentials (between 20 and 200 mV) and times (between 0 and 5 h). Under these conditions, we observed the initial formation of ‘green rust’ (hydroxychlorides and/or hydroxycarbonates), followed by the formation of magnetite (Fe3O4) and then a mixture of the α‐ and γ‐FeOOH (goethite and lepidocrocite, respectively). These data are consistent with a model for corrosion during which the initially formed magnetite is either covered, or replaced, by layers of the FeOOH oxidation products. Fitting of the data as a function of time and potential shows that, although the product range is independent of potential, the relative kinetics of formation of magnetite and its subsequent conversion to the γ‐FeOOH were potential and time dependent. Analysis by mapping of the dry corroded surface showed a variety of species, including green rust, some Fe(OH)3, as well as the γ‐FeOOH, and possibly some β‐FeOOH. But no surface magnetite was found, indicating that this material had been either covered up or converted to FeOOH. We noted several complications during this work, including the interference of resonance effects (on the Raman intensities) and the heterogeneity of the corrosion process (and hence distribution of species on the corroded surface). However, we believe that the use of un‐enhanced Raman methods has led to conclusions more likely to be relevant to ‘real’ corrosion processes. Copyright © 2007 John Wiley & Sons, Ltd.
Radio‐guided surgery in neuroendocrine tumors
Authors: Gulec Seza A , Baum Richard 
Published: August 2007

AbstractThe majority of Neuroendocrine tumors (NET) express somatostatin (SS) receptors, and thus can be successfully targeted with radiolabeled SS analogs in vivo. Somatostatin receptor scintigraphy (SRS) with 111In‐DTPA Octreotide is the main imaging technique for evaluation of NETs. Radio‐guided surgery for NETs, therefore, primarily utilizes 111In‐DTPA Octreotide tumor localization mechanism and kinetics. Somatostatin analog radiopharmacy continues to evolve to include the development of more selective and higher affinity analogs and PET tracers. These changes are expected to open new venues for radio‐guided surgery technology. J. Surg. Oncol. 2007;96:309–315. © 2007 Wiley‐Liss, Inc.
Radioimmunoguided surgery (RIGS), PET/CT image‐guided surgery, and fluorescence image‐guided surgery: Past, present, and future
Authors: Sun Duxin , Bloomston Mark , Hinkle George , Al‐Saif Osama Habib , Hall Nathan C. , Povoski Stephen P. , Arnold Mark W. , Martin Edward W. 
Published: August 2007

Abstract125I‐labeled anti‐TAG‐72 antibodies were applied in radioimmunoguided surgery (RIGS) to remove gross and occult tumors. It is challenging to handle 125I‐labeled materials. PET/CT image‐guided surgery utilizes 18FDG to monitor the biochemical activity of the tumor and to integrate pre‐ and postoperative imaging for complete tumor removal. PET/CT image‐guided surgery only detects later stage disease. Fluorescence image‐guided surgery using anti‐TAG‐72 antibodies may provide opportunities for intraoperative cancer detection of both gross and occult tumors. J. Surg. Oncol. 2007;96:297–308. © 2007 Wiley‐Liss, Inc.
The formation of the tourist's loyalty to the tourism distribution channel: how does it affect price discounts?
Authors: Campo Sara , Yagüe Maria Jesús 
Published: August 2007

AbstractGiven that distribution agents who wish to maximize long‐term business profits should not only attract new consumers but also keep them loyal, this study analyses the variables that determine the consumer's loyalty to distribution agents for tourism. Although retailers in the service industry employ price discounts on products to motivate short‐term sales, they often establish promotional policies without considering their effect on the long‐term business results. This paper presents an empirical study of the effect of price promotions on tourists who travelled with a package tour. The results indicate that price discounts do not erode consumer loyalty directly, and that the key to obtaining loyal consumers is to offer package tours that customers perceive as providing high‐quality service. Copyright © 2007 John Wiley & Sons, Ltd.
Community development using a sustainable tourism strategy: a case study of the Jordan River Valley touristway
Authors: Shunnaq Mohammed , Schwab William A. , Reid Margaret F. 
Published: August 2007

AbstractThis paper presents the results of a 10‐year collaboration among Yarmouk University, the University of Arkansas and the Jordanian government to develop a sustainable tourism strategy against the backdrop of political and economic uncertainty. It reports our efforts to develop a touristway through the Jordan River Valley that integrates the valley's heritage, archeology, and Christian and Islamic religious sites. It also analyses our community development work in Umm Qais, the touristway's northern anchor, and how our plan contributes to Northern Jordan's economic development. We conclude with a discussion of the specific insights gained from our experiences that may serve others addressing similar issues. Copyright © 2007 John Wiley & Sons, Ltd.