bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis and Redox Behaviour of the Chalcogenocarbonyl Dianions [(E)C(PPh2S)2]2−: Formation and Structures of Chalcogen–Chalcogen Bonded Dimers and a Novel Selone
Authors: Konu Jari , Chivers Tristram , Tuononen Heikki M. 
Published: September 2010

AbstractThe lithium salts of the chalcogenocarbonyl dianions [(E)C(PPh2S)2]2− (E=S (4 b), Se (4 c)) were produced through the reactions between Li2[C(PPh2S)2] and elemental chalcogens in the presence of tetramethylethylenediamine (TMEDA). The solid‐state structure of {[Li(TMEDA)]2[(Se)C(PPh2S)2]}—[{Li(TMEDA)}24 c]—was shown to be bicyclic with the Li+ cations bis‐S,Se‐chelated by the dianionic ligand. One‐electron oxidation of the dianions 4 b and 4 c with iodine afforded the diamagnetic complexes {[Li(TMEDA)]2[(SPh2P)2CEEC(PPh2S)2]} ([Li(TMEDA)]27 b (E=S), [Li(TMEDA)]27 c (E=Se)), which are formally dimers of the radical anions [(E)C(PPh2S)2]−. (E=S (5 b), Se (5 c)) with elongated central EE bonds. Two‐electron oxidation of the selenium‐containing dianion 4 c with I2 yielded the LiI adduct of a neutral selone {[Li(TMEDA)][I(Se)C(PPh2S)2]}—[{LiI(TMEDA)}6 c]—whereas the analogous reaction with 4 b resulted in the formation of 7 b followed by protonation to give {[Li(TMEDA)][(SPh2P)2CSS(H)C(PPh2S)2]}—[Li(TMEDA)]8 b. Attempts to identify the transient radicals 5 b and 5 c by EPR spectroscopy in conjunction with DFT calculations of the electronic structures of these paramagnetic species and their dimers are also described. The crystal structures of [{Li(TMEDA)}24 c], [{LiI(TMEDA)}6 c]⋅C7H8, [Li(TMEDA)]27 b⋅(CH2Cl2)0.33, [Li(THF)2]27 b, [Li(TMEDA)]27 c, [Li(TMEDA)]8 b⋅(CH2Cl2)2 and [Li([12]crown‐4)2]8 b were determined and salient structural features are discussed.
A Rationale of the Baeyer–Villiger Oxidation of Cyclohexanone to ε‐Caprolactone with Hydrogen Peroxide: Unprecedented Evidence for a Radical Mechanism Controlling Reactivity
Authors: Cavani Fabrizio , Raabova Katerina , Bigi Franca , Quarantelli Carla 
Published: September 2010

AbstractWe demonstrate, for the first time, in the Baeyer–Villiger oxidation of cyclohexanone with aqueous hydrogen peroxide under conditions aimed at obtaining ε‐caprolactone, that a thermally activated radical reaction leads to the concurrent formation of adipic acid, even when a stoichiometric amount of the oxidant is used. In fact, ε‐caprolactone is the primary reaction product, but it is more reactive than cyclohexanone, and quickly undergoes consecutive transformations. When titanium silicalite‐1 (TS‐1) is used as a catalyst, the high concentration of hydroxy radicals within its pores accelerates the reaction rates, and the consecutive formation of adipic acid (and of lighter diacids as well) becomes largely kinetically preferred. The proper choice of the solvent, which also may act as a radical scavenger, both without catalyst and with TS‐1, is a powerful tool for controlling the rates of the various reactions involved.
Biosorption Kinetics and Isotherm Studies of Cd(II) by Dried Enteromorpha compressa Macroalgae Cells from Aqueous Solutions
Authors: Sahmurova Aida , Türkmenler Harun , Özbaş Emine Elmaslar 
Published: September 2010

AbstractFor the first time ever, Enteromorpha compressa macroalgae (ECM), which is commonly found in Turkey, has been used as biosorbent by us. This study aims to investigate the biosorption of Cd2+ from aqueous solutions in a batch system by using an alga of ECM in different concentrations, pH levels, agitation rates (90–150 rpm), and contact periods. The maximum biosorption capacity of the ECM was found to be 9.50 mg/g at pH 6, Cd2+ initial concentration of 10 mg/L and agitation rate 150 rpm. Cadmium removal efficiency was about 95%. The experimental isotherm data were analyzed using the Langmuir and Freundlich equations. Isotherm parameters for both equations were determined and discussed. The stated biosorption mechanism is explained by the Freundlich isotherm (r2 = 0.998) theory. Two simplified kinetic models including a pseudo‐first‐ and second‐order equation were selected to follow the biosorption process. Kinetic parameters; rate constants, equilibrium adsorption capacities and related correlation coefficients, for each kinetic model were calculated and discussed. It was shown that the biosorption of cadmium onto ECM could be described by the pseudo‐second‐order equation (r2 > 0.99).
Scalability of pseudospectral methods for geodynamo simulations
Authors: Davies Christopher J. , Gubbins David , Jimack Peter K. 
Published: September 2010

AbstractThe problem of understanding how Earth's magnetic field is generated is one of the foremost challenges in modern science. It is believed to be generated by a dynamo process, where the complex motions of an electrically conducting fluid provide the inductive action to sustain the field against the effects of dissipation. Current dynamo simulations, based on the numerical approximation to the governing equations of magnetohydrodynamics, cannot reach the very rapid rotation rates and low viscosities (i.e. low Ekman number) of Earth due to limitations in available computing power. Using a pseudospectral method, the most widely used method for simulating the geodynamo, computational requirements needed to run simulations in an ‘Earth‐like’ parameter regime are explored theoretically by approximating operation counts, memory requirements and communication costs in the asymptotic limit of large problem size. Theoretical scalings are tested using numerical calculations. For asymptotically large problems the spherical transform is shown to be the limiting step within the pseudospectral method; memory requirements and communication costs are asymptotically negligible. Another limitation comes from the parallel implementation, however, this is unlikely to be threatened soon and we conclude that the pseudospectral method will remain competitive for the next decade. Extrapolating numerical results based upon the code analysis shows that simulating a problem characterizing the Earth with Ekman number E = 10−9 would require at least 13 000 days per magnetic diffusion time with 54 000 available processors, a formidable computational challenge. At E = 10−8 an allocation of around 350 million CPU hours would compute a single diffusion time, many more CPU hours than are available in current supercomputing allocations but potentially reachable in the next decade. Exploration of the 10−6⩽E⩽10−7 regime could be performed at the present time using a substantial share of national supercomputing facilities or a dedicated cluster. Copyright © 2010 John Wiley & Sons, Ltd.
Mindfulness‐based stress reduction (MBSR) and distress in a community‐based sample
Authors: Evans Susan , Ferrando Stephen , Carr Corey , Haglin Dean 
Published: September 2010

AbstractBackground: Numerous studies have found Mindfulness‐based stress reduction (MBSR) to be useful for a wide range of problems including anxiety, pain and coping with a medical illness. The primary goal of this study was to evaluate the effectiveness of an 8‐week MBSR programme in relieving distress in a community based sample.Methods: Subjects (n = 14) were participants in the MBSR programme at a major academic medical center and completed the Profile of Mood States (POMS) and the Mindful Attention Awareness Scale (MAAS) prior to starting the class and at the end of the 8‐week course. Means and standard deviations were computed for the pre‐and post‐POMS total and subscale measures and the MAAS. Wilcoxon Signed Ranks Test was conducted. Results: There were significant reductions on multiple dimensions of distress on the POMS as well as a significant increase in mindful awareness as measured by the MAAS.Conclusion: These results suggest that MBSR appears to be associated with a reduction of distress and increased awareness of everyday life experiences in a sample of residents living in a large urban community. Copyright © 2010 John Wiley & Sons, Ltd.Key Practitioner Message:• Mindfulness‐based stress reduction (MBSR) appears to be an acceptable modality for mild to moderate psychological distress in a community sample.• Mindfulness training is associated with reduction in psychological distress.• Mindful Attention Awareness scale scores improved following an 8‐week MBSR course.
Synthesis and Characterization of Some Carbon Based Nanostructures
Authors: Ciupina V. , Sullivan J. , Saied S. , Vladoiu R. , Prodan G. , Oancea‐Stanescu I.M. , Mandes A. , Contulov M. , Dinca V. , Prodan M. , Manole D. 
Published: September 2010

AbstractCarbon thin films were synthesized using the original Thermionic Vacuum Arc (TVA) method. Mechanical properties were investigated using Micro Materials NanoTest 500 instrument using a NT Berkovich indenter. XPS provides a quantitative analysis of the surface composition and X‐ray generated Auger electron spectroscopy (XAES) performed by Thermoelectron ESCALAB 250 revealed information about the sp3:sp2 ratio of the carbon bondings. Structure and morphology was studied by Transmission Electron Microscope CM120ST, providing information on the grain size distribution of the crystalline diamond structures (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Intracerebral estrogen provision increases cytogenesis and neurogenesis in the injured zebra finch brain
Authors: Walters Bradley J. , Alexiades Nikita G. , Saldanha Colin J. 
Published: September 2010

AbstractTo determine whether or not local, injury‐induced aromatization and/or estrogen provision can affect cyto‐ or neuro‐genesis following mechanical brain damage, two groups of adult male zebra finches sustained bilateral penetrating brain injuries. The first received contralateral injections of vehicle or the aromatase inhibitor fadrozole. The second group received contalateral injections of fadrozole, or fadrozole with 17β‐estradiol. Subsequent to injury, birds were injected with the thymidine analog 5‐bromo‐2′‐deoxyuridine (BrdU). Two weeks following injury, the birds were perfused, and coronal sections were labeled using antibodies against BrdU and the neuronal proteins HuC/HuD. In a double blind fashion, BrdU positive cells and BrdU/Hu double‐labeled cells in the subventricular zone (SVZ) and at the injury site (INJ) were imaged and sampled. The average numbers of cells per image were compared across brain regions and treatments using repeated measures ANOVAs and, where applicable, post‐hoc, pairwise comparisons. Fadrozole administration had no detectable effect on cytogenesis or neurogenesis, however, fadrozole coupled with estradiol significantly increased both measures. The dorsal SVZ had the greatest proportion of new cells that differentiated into neurons, though the highest numbers of BrdU labeled and BrdU, Hu double‐labeled cells were detected at the INJ. In the adult zebra finch brain, local estradiol provision can increase cytogenesis and neurogenesis, however, whether or not endogenous glial aromatization is sufficient to similarly affect these processes remains to be seen. © 2010 Wiley Periodicals, Inc. Develop Neurobiol 71: 170‐181, 2011
4d vs. 5d – Reactivity and Fate of Terminal Nitrido Complexes of Rhodium and Iridium
Authors: Schöffel Julia , Šušnjar Nevena , Nückel Stefan , Sieh Daniel , Burger Peter 
Published: September 2010

AbstractThe stability of (pyridinediimine)rhodium– and ‐iridium–azido complexes was studied by a combination of thermoanalytical methods (DTG/MS and DSC) and DFT calculations. On a preparative scale, the isolation and X‐ray crystallographic characterization of the thermolysis products confirmed intramolecular C–H activation processes with concomitant reorganisation of C–C, C–N, N–H and Ir–N bonds to yield tuck‐in complexes with a different constitution of the ligand framework for the Rh and Ir products. The tentatively formed (Rh) or initially present (Ir) nitrido unit was converted into either an amine (Rh) or amido (Ir) moiety. Furthermore, the dimerization of the nitrido complexes to the corresponding dinitrogen compounds, i.e. 2 LnM≡N → LnM–N2–MLn, was investigated. Experimental evidence for the relevance of this step was provided by the isolation and X‐ray crystallographic characterization of a related dinuclear N2‐bridged (pyridinediimine)dirhodium complex. DFT calculations revealed that the formation of dinitrogen complexes is thermodynamically strongly favourable and evidenced that the previous isolation of a terminal iridium–nitrido complex was possible due to a high barrier for the dimerization process and a sizeable barrier for the intramolecular C–H activation step.
Trans octadecenoic fatty acid (TFA) isomers in German foods and bakery goods
Authors: Fritsche Jan , Petersen Katharina D. , Jahreis Gerhard 
Published: September 2010

AbstractIn the present study, 122 food samples from the German food market were analysed for their C18:1 trans fatty acid (TFA) content and profile. A particular focus of the survey were baked and fried foods. TFA analysis was performed by means of silver ion SPE (Ag+‐SPE) in combination with high‐resolution GC (HRGC‐FID). Overall, 51 bakery product samples were analysed of which 25 samples were prepacked bakery products purchased from local retail stores and 26 samples of unpacked bakery products purchased from local bakery shops. In addition, 14 French fries samples obtained from small local fast food restaurants as well as from internationally operating fast food chains, 27 potato and tortillas chips, 15 instant soups as well as 15 dry culinary sauces were analysed. The highest amounts of C18:1 TFA isomers were found in deep‐fried bakery products. Prepacked branded cookies and biscuits on the other hand contained only negligible C18:1 TFA amounts. Regarding their C18:1 trans isomer profile most deep‐fried bakery products exhibited a Gaussian‐distributed isomer profile. The analysed prepacked croissants, cookies and biscuits contained predominantly ruminant TFA (TFA) as suggested by the presence of vaccenic acid (C18:1 trans 11), which was the major C18:1 TFA isomer in these products. All non‐bakery samples (n = 71) contained less than 3 g C18:1 TFA per 100 g fat. In conclusion, TFA still occur in considerable amounts in a few German food products, especially in some deep‐fried bakery products (‘Berliner’ type of doughnuts).Practical applications: Trans fatty acids, in particular the trans octadecenoic fatty acid isomers (C18:1), are generally considered from the nutritional point of view as undesirable food components due to their negative health effects. Tremendous efforts have been made by major food processors in order to decrease or even eliminate the presence of TFA in some foodstuffs (e.g. in margarines in European countries). However, some food processors of other food sectors are still applying oils and fats containing partially hydrogenated vegetable oils, whereas others within the same food category have already switched their processing conditions and/or raw materials towards TFA alternatives. Therefore, actual TFA data of foodstuffs determined by means of state‐of‐the‐art analytical procedures (Ag+‐SPE in combination with GC‐FID) is necessary to detect areas of further improvement in the food supply chain and to provide data for an update of dietary TFA intake.
An Efficient Synthesis of 7‐(Arylmethyl)‐3‐tert‐butyl‐1‐phenyl‐6,7‐dihydro‐1H,4H‐pyrazolo[3,4‐d][1,3]oxazines
Authors: Abonia Rodrigo , Castillo Juan , Insuasty Braulio , Quiroga Jairo , Nogueras Manuel , Cobo Justo 
Published: September 2010

AbstractAn efficient and three‐step procedure for the synthesis of novel 6,7‐dihydro‐1H,4H‐pyrazolo[3,4‐d][1,3]oxazine derivatives in good to excellent yields by treatment of pyrazolamines with aqueous formaldehyde in the presence of acetic acid is provided. The reactions proceeded through an intramolecular etherification process by dehydration of a 1,5‐diol intermediate formed in the course of the reaction and promoted by acid media.
A Xanthene–Benzimidazole Receptor with Multiple H‐Bond Donors for Carboxylic Acids
Authors: Muñiz Francisco M. , Alcázar Victoria , Sanz Francisca , Simón Luis , Fuentes de Arriba Ángel L. , Raposo César , Morán Joaquín R. 
Published: September 2010

AbstractThe combination of two benzimidazole moieties with a spacer formed by a leucine unit and a xanthene skeleton provides an efficient receptor for neutral guests with oxygen atoms such as sulfoxides, ketones, or alcohols. 1H NMR and UV spectroscopic techniques have been used to evaluate its binding ability. These experiments indicated the largest association constants for carboxylic acids and different binding stoichiometries. The structures of these different complexes were studied both in solution and in the solid state. Fluorescence of anthracenecarboxylic acid is strongly quenched in the presence of receptor 1, and therefore, this system could be used to sense the presence of stronger carboxylic acids and anions like chloride.
Asymmetric Synthesis of O‐Protected Acyloins Using Enoate Reductases: Stereochemical Control through Protecting Group Modification
Authors: Winkler Christoph K. , Stueckler Clemens , Mueller Nicole J. , Pressnitz Desiree , Faber Kurt 
Published: September 2010

AbstractO‐Protected cyclic acyloins were obtained in nonracemic form through asymmetric bioreduction of α,β‐unsaturated alkoxy ketones by using 11 different enoate reductases from the “Old Yellow Enzyme” family. The stereochemical outcome of the biotransformation could be switched by variation of the O‐protecting group or by the ring size of the substrate, which allows access to both stereoisomers in up to >97 % ee Whereas α‐alkoxy enones were readily accepted as substrates, β‐analogs were not converted. Overall, α‐alkoxy enones represent a novel type of substrate for flavin‐dependent ene‐reductases.
Regiocontrolled Synthesis of Ring‐Fused Thieno[2,3‐c]pyrazoles through 1,3‐Dipolar Cycloaddition of Nitrile Imines with Sulfur‐Based Acetylenes
Authors: Chandanshive Jay Zumbar , Bonini Bianca Flavia , Gentili Denis , Fochi Mariafrancesca , Bernardi Luca , Franchini Mauro Comes 
Published: September 2010

Abstract1,3‐Dipolar cycloadditions of C‐carboxymethyl‐N‐arylnitrile imines with substituted acetylenes bearing thiol or sulfone groups were studied. The sulfur controls the regiochemistry of the reaction, and this protocol was applied to the synthesis of ring‐fused thieno[2,3‐c]pyrazoles.
A multivariate approach to the analysis of air quality in a high environmental risk area
Authors: Pollice Alessio , Jona Lasinio Giovanna 
Published: September 2010

AbstractThis study analyzes air quality data in the Taranto municipal area. This is a high environmental risk region being characterized by the massive presence of industrial sites with elevated environmental impact activities. We focus on three pollutants formed by combustion processes and related to meteorological conditions, namely particulate matter, sulphur dioxide, and nitrogen dioxide. Preliminary analysis involved addressing several data problems. First of all an imputation technique was considered to cope with the large number of missing data. Missing data imputation was addressed by a leave‐one‐out procedure based on the recursive Bayesian estimation and prediction of spatial linear mixed effects (LME) models enriched by a time‐recursive prior structure. Secondly, a unique daily weather database at the city level was obtained combining data from three stations, characterized by gaps and unreliable measurements. Spatio‐temporal modeling of the multivariate normalized daily pollution data was then performed within a Bayesian hierarchical framework, including time varying weather covariates and a semi‐parametric spatial covariance structure. Daily estimates of the pollutants' concentration surfaces allow us to identify areas of higher concentration (hot spots), possibly related to specific anthropic activities. Copyright © 2010 John Wiley & Sons, Ltd.
Efficient immune‐GA method for DNOs in sizing and placement of distributed generation units
Authors: Soroudi Alireza , Ehsan Mehdi 
Published: September 2010

AbstractThis paper proposes a hybrid heuristic optimization method based on genetic algorithm and immune systems to maximize the benefits of Distribution Network Operators (DNOs) accrued due to sizing and placement of Distributed Generation (DG) units in distribution networks. The effects of DG units in reducing the reinforcement costs and active power losses of distribution network have been investigated. In the presented method, the integration of DG units in distribution network is done considering both technical and economical aspects. The strength of the proposed method is evaluated by applying it on a small and a realistic large scale distribution network and the results are compared with analytical classic and other heuristic methods and discussed. Copyright © 2010 John Wiley & Sons, Ltd.
A multivariate forecasting method for short‐term load using chaotic features and RBF neural network
Authors: Liu Yuming , Lei Shaolan , Sun Caixin , Zhou Quan , Ren Haijun 
Published: September 2010

AbstractThis paper presents a multivariate forecasting method for electric short‐term load using chaos theory and radial basis function (RBF) neural networks. To apply the method, the largest Lyapunov exponent and correlation dimension are firstly calculated which show the electric load series is essentially a chaotic time series. Then, a multivariate chaotic prediction method is proposed taking historical load and temperature into account. Phase space reconstruction of a univariate time series is extended to construct a multivariate time series. Delay time and embedding dimension of the historical load series and temperature series are determined by mutual information and minimal forecasting error, respectively. Finally, a three‐layer RBF neural network is employed to forecast the load of one day ahead and one week ahead. Real load data of Chongqing Power Grid are tested. Daily and weekly forecasting results show that the proposed multivariate approach improves the accuracy of forecasting significantly comparing with the univariate methods. Discussion of forecasting error and future work are also presented. As an efficient and effective alternative for STLF, the chaos theory based multivariate forecasting is feasible for potential application. Copyright © 2010 John Wiley & Sons, Ltd.
Impact of power factor regulation on small‐signal stability of power distribution systems with distributed synchronous generators
Authors: Salim R. H. , Kuiava R. , Ramos R. A. , Bretas N. G. 
Published: September 2010

AbstractDistributed generation (DG) usage is increasing nowadays, specially in the wider sense of microgrids. Its technical impacts and restrictions are still under study, and in several aspects are kept almost untouched. One of these aspects is the small‐signal stability of distribution systems in the presence of distributed synchronous generators (DSG). This paper deals with such problem, presenting a comprehensive small‐signal stability study of a system under the specified conditions. The study considers two types of excitation control for synchronous generators: voltage and power factor. The focus, however, is on the latter, since it is the most widely used in distributed generators connected to distribution grids. Thus, a comparative analysis between these two control strategies is performed, allowing the investigation of their effects on the small‐signal stability of a power distribution system (PDS). This comparative analysis is performed with respect to the characteristics of its electromechanical oscillation modes (EOM) under several DG penetration levels. Copyright © 2010 John Wiley & Sons, Ltd.