bluuebunny/crossref_metadata_2025_split huggingface dataset:
Creation of Stabilized Electrochromic Materials by Taking Advantage of Azulene Skeletons
Authors: Ito Shunji , Morita Noboru 
Published: July 2009

AbstractThe preparative scope of the new structural principle of utilization of azulene skeletons as redox‐active chromophores for the production of stabilized electrochromic materials is demonstrated in several examples. The structural principle takes advantage both of the cyanine‐type polymethine dyes and of the violene‐type redox systems. Appropriate combination of cyanine and/or violene substructures will produce at least one cyanine‐type structure in the reduced or oxidized form through an overall two‐electron transfer, although some will produce a cross‐conjugated cyanine‐type structure. Hünig's violene–cyanine hybrid structures, utilizing the bis(enediyne) system, afford electrochromic materials that exhibit strong absorptions in the near‐infrared region in the dianionic state. Cyanine–cyanine hybrid structures, consisting of pairs of cyanine units, show two‐step color changes based on single electron transfer in each step. Combinations of the cyanine and/or the violene substructures permit the design of novel stabilized electrochromic systems, including polyelectrochromic systems. The flexibility of the structural principle is demonstrated by the violene–violene hybrid, violene–cyanine–cyanine hybrid, violene‐cyanine‐violene hybrid, andviolene‐violene‐violene hybrid structures. New examples of the violene‐like redox system with inverse electron demand are provided by 6‐aminoazulene derivatives. The liquid‐crystalline properties of the redox‐active columnar mesogen are revealed by several azulene‐substituted electrochromic materials.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
Selective Cyclodimerization and Cyclotrimerization of Acetals Bearing Electron‐Withdrawing Groups Catalyzed by Lewis Acids
Authors: Maeda Sayuki , Obora Yasushi , Ishii Yasutaka 
Published: July 2009

AbstractAcetals like 3,3‐diethoxypropionate bearing electron‐withdrawing groups were found to undergo cyclodimerization and cyclotrimerization in the presence of Lewis acids to give coumalates and 1,3,5‐trisubstituted benzenes. The selectivity of these products depended on the Lewis acids employed. For instance, ethyl coumalate was obtained from ethyl 3,3‐diethoxypropionate in high selectivity under the influence of d‐block Lewis acids like FeCl3, whereas triethyl 1,3,5‐benzenetricarboxylate was obtained in preference to ethyl coumalate under the influence of lanthanoid Lewis acids like GdCl3. Various coumalates were synthesized by the FeCl3‐catalyzed cross‐cyclodimerization of acetals with active methylene compounds. From 4,4‐dimethoxy‐2‐butanone, however, 1,3,5‐triacetylbenzene, which is difficult to prepare regioselectively by conventional methods, was formed in quantitative yield under the influence of AlCl3. This reaction would provide a very convenient route to 1,3,5‐triacetylbenzene. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
Synthesis and Hormonal Activity of the (25S)‐Cholesten‐26‐oic Acids – Potent Ligands for the DAF‐12 Receptor in Caenorhabditis elegans (Eur. J. Org. Chem. 22/2009)
Authors: Martin René , Entchev Eugeni V. , Däbritz Frank , Kurzchalia Teymuras V. , Knölker Hans‐Joachim 
Published: July 2009

AbstractThe cover picture shows the bioactivity for rescue of diapause in daf‐9(dh6) mutant worms using (25S)‐Δ7‐dafachronic acid (structure, bottom left). The fluorescence label (represented by purple spots) marks the daf‐9(dh6); dhEx24 mutant worms that develop into adults without the requirement of exogenous hormonally active steroidal acid. The daf‐9(dh6) mutant worms (no fluorescence, at the bottom) can develop into adults by using (25S)‐Δ7‐dafachronic acid at concentrations down to 10 nM (top right). Details are discussed in the article by H.‐J. Knölker et al. on p. 3703 ff.
FTIR‐ATR Study of Water Uptake and Diffusion Through Ion‐Selective Membranes Based on Plasticized Poly(vinyl chloride)
Authors: Lindfors Tom , Sundfors Fredrik , Höfler Lajos , Gyurcsányi Róbert E. 
Published: July 2009

AbstractIn this paper, the water uptake and diffusion of water through ion‐selective membranes based on plasticized poly(vinyl chloride) (PVC) have been studied by FTIR‐ATR spectroscopy. The diffusion of water was modeled by the finite‐difference method and the obtained diffusion coefficients are reported for membranes plasticized with bis(2‐ethylhexyl) sebacate (DOS) and 2‐nitrophenyl octyl ether (oNPOE). The influence of various common membrane additives such as lipophilic salts and ionophores on the water uptake was also determined through representative membrane formulations (potassium tetrakis[3,5‐bis(trifluoromethyl)phenyl]borate (KTFPB) and/or calcium ionophore IV (ETH 5234)). The best fits of the time dependent water concentration changes in the membrane upon water uptake were obtained with a model consisting of two diffusion coefficients describing fast (ca. 1.5×10−7 cm2 s−1) and slow (ca. 9.5×10−9 cm2 s−1) diffusion of water in the PVC membranes. In contrast to the water uptake of the membranes, the diffusion rates were found to be practically independent of the membrane composition. It is shown that KTFPB and ETH 5234 decrease the water uptake whereas it is facilitated by a higher plasticizer content of the membrane. Monomeric, dimeric, clustered and bulk water could be distinguished by deconvolution of the FTIR‐ATR spectra, which is important for understanding the water uptake mechanism.
Solid Contact Micropipette Ion Selective Electrode II: Potassium Electrode for SECM and In Vivo Applications
Authors: Gyetvai Gergely , Nagy Lívia , Ivaska Ari , Hernadi István , Nagy Géza 
Published: July 2009

AbstractMicropipette ion selective electrodes are very small, but fragile, short‐life time sensors with very high resistance. Their high resistance is a draw back considering application in scanning electrochemical microscopy (SECM) and in life sciences. New, low resistance potassium micropipette electrodes were prepared, and applied. The electrode contains solid internal contact made of a carbon fiber lowered down all the way close to the orifice of the micropipette. The internal contact potential was kept constant by applying a doped, electrochemically prepared PEDOT coating on the fiber surface. The electrode performed well in in vivo experiments both in plant and animal tissue without capacitance neutralization and in SECM.
Fast Response, Noninvasive, Potentiometric Microelectrodes Resolve Single Potassium Channel Activity in the Diffusive Boundary Layer of a Single Cell
Authors: Messerli Mark A. , Collis Leon P. , Smith Peter J. S. 
Published: July 2009

AbstractIon transport across the plasma membrane of cells involves an inevitable chemical modification of the solutions on both sides. Noninvasive, real‐time detection of these subtle ionic signatures is most easily achieved in the extracellular diffusive boundary layer with electrochemical detection. In order to perform these measurements near single cells it is critical to use a device that enables high spatial and temporal resolution. While ion‐selective microelectrodes (ISMs) provide the high spatial resolution, they give rise to orders of magnitude increase in the time constant and response time of the microsensors when compared to larger sensors. By constructing and using fast response ISMs biological events as brief as 10 ms have been resolved. The signal‐to‐noise ratio is enhanced with self‐referencing and signal processing techniques, enabling long‐term monitoring of small magnitude, steady ion gradients and rapid ionic transients that reflect the physiological and metabolic activity of single cells.
Amperometric Ion‐Selective Electrode for Alkali Metal Cations Based on a Room‐Temperature Ionic Liquid Membrane
Authors: Langmaier Jan , Trojánek Antonín , Samec Zdenĕk 
Published: July 2009

AbstractCyclic voltammetry is used to study the transfer of a series of cations and anions across a room‐temperature ionic liquid membrane composed of tridodecylmethylammonium cation and tetrakis[3,5‐bis(trifluoromethyl) phenyl]borate anion. It is shown that the addition of water‐soluble crown ether (e.g. 18‐crown‐6) to the aqueous phase makes it possible to distinguish the voltammetric responses of alkali and alkaline earth metal cations. The determination of low concentrations of K+ (0.05–0.3 mM) in the presence of an excess of Mg2+ (1 mM) in water is demonstrated as a model application of an amperometric ion‐selective electrode for K+.
Determination of Calcium with Ion‐Selective Electrode in Black Liquor from a Kraft Pulping Process
Authors: Granholm Kim , Ek Paul , Sokalski Tomasz , Harju Leo , Bobacka Johan , Ivaska Ari 
Published: July 2009

AbstractA solid‐contact Ca2+‐selective electrode was used to study speciation of calcium in black liquor. During extended time of operation the standard potential was found to change, but the sensitivity of the electrode, and the selectivity coefficients remained unchanged. Laser ablation inductively coupled plasma mass spectrometry (LA‐ICP‐MS) measurements showed sodium sorption to the electrode membrane during the measurement in black liquor. Linearization of the complexometric titration curves were used to determine the concentrations of Ca2+, CaOH+ as well as weak and strong calcium complexes. With inductively coupled plasma optical emission spectrometry (ICP‐OES), similar total calcium concentrations were obtained as by the EDTA titration.
Water Transport in Poly(n‐butyl acrylate) Ion‐Selective Membranes
Authors: Appiah‐Kusi Charles , Kew Simon J. , Hall Elizabeth 
Published: July 2009

AbstractWater transport across poly(n‐butyl acrylate) membranes is a critical process in the mechanism of operation for the ion‐selective layers used in the construction of electrodes that detect ionic species. We report the results from a hologram‐membrane composite which was used to characterize the rate of water transport through the ion‐selective membrane. A diffusion coefficient, Dapp≈10−6 cm2 s−1 was estimated from holographic data and confirmed by FTIR data. An osmotic pressure driven mechanism was rejected and Case II diffusion of water vapor was indicated, suggesting low condensation within the membrane itself. FTIR spectroscopy was also used to characterize the water species at an interface with the membrane revealing composition‐dependent water transport equilibria.
Inducing Sensitivity to Heavy Metal Ions in Polypyrrole Modified by Azamacrocyclic Ligands
Authors: Pawłowski Paweł , Maksymiuk Krzysztof , Tamanini Emiliano , Watkinson Michael , Michalska Agata , Hall Elizabeth A. H. 
Published: July 2009

AbstractAn azamacrocyle doped polypyrrole is considered as a material showing heavy metal cation sensitivity and examples with Ni2+, Zn2+, and Cu2+ cations are tested. Heavy metal ion binding agent: 1,4,8,11‐tetraazacyclotetradecane (cyclam) or its derivatives were introduced into a conducting polymer film in different ways: i) neutral cyclam was incorporated by polymerization from 1,4,8,11‐tetraazacyclotetradecane containing solution, ii) 1,4,8,11‐tetraazacyclotetradecane‐1,4,8,11‐tetraacetate anions (TETA) were introduced, acting as co‐dopant ions in chloride containing solutions, iii) polymerization was carried out from solution containing pyrrole and a composite of pyrrole with Ni(II) cyclam derivative complex: N‐(4‐amino‐6‐(1,3,5,8,12‐pentaazacyclotetradecan‐3‐yl)‐1,3,5‐triazin‐2‐yl)‐1H‐pyrrole‐2‐carboxamide nickel(II) perchlorate (ET679). In KCl and NiCl2 solutions the freshly obtained oxidized polypyrrole layers modified by cyclam or TETA anions exhibited typical anion exchanging properties as confirmed in voltammetric and potentiometric experiments. Potentiometric cationic sensitivity and selectivity towards nickel ions was induced after conditioning or polarization in alkaline (NaOH or KOH) media and Ni2+ solution; this was accompanied by Ni(II) retention in the polymer film. Similar cationic sensitivity was observed also for polypyrrole with cyclam in case of Zn2+ and Cu2+ ions.
Multivariate log‐skew‐elliptical distributions with applications to precipitation data
Authors: Marchenko Yulia V. , Genton Marc G. 
Published: July 2009

AbstractWe introduce a family of multivariate log‐skew‐elliptical distributions, extending the list of multivariate distributions with positive support. We investigate their probabilistic properties such as stochastic representations, marginal and conditional distributions, and existence of moments, as well as inferential properties. We demonstrate, for example, that as for the log‐t distribution, the positive moments of the log‐skew‐t distribution do not exist. Our emphasis is on two special cases, the log‐skew‐normal and log‐skew‐t distributions, which we use to analyze US national (univariate) and regional (multivariate) monthly precipitation data. Copyright © 2009 John Wiley & Sons, Ltd.
Incremental dynamic analysis for estimating seismic performance sensitivity and uncertainty
Authors: Vamvatsikos Dimitrios , Fragiadakis Michalis 
Published: July 2009

AbstractIncremental dynamic analysis (IDA) is presented as a powerful tool to evaluate the variability in the seismic demand and capacity of non‐deterministic structural models, building upon existing methodologies of Monte Carlo simulation and approximate moment‐estimation. A nine‐story steel moment‐resisting frame is used as a testbed, employing parameterized moment‐rotation relationships with non‐deterministic quadrilinear backbones for the beam plastic‐hinges. The uncertain properties of the backbones include the yield moment, the post‐yield hardening ratio, the end‐of‐hardening rotation, the slope of the descending branch, the residual moment capacity and the ultimate rotation reached. IDA is employed to accurately assess the seismic performance of the model for any combination of the parameters by performing multiple nonlinear timehistory analyses for a suite of ground motion records. Sensitivity analyses on both the IDA and the static pushover level reveal the yield moment and the two rotational‐ductility parameters to be the most influential for the frame behavior. To propagate the parametric uncertainty to the actual seismic performance we employ (a) Monte Carlo simulation with latin hypercube sampling, (b) point‐estimate and (c) first‐order second‐moment techniques, thus offering competing methods that represent different compromises between speed and accuracy. The final results provide firm ground for challenging current assumptions in seismic guidelines on using a median‐parameter model to estimate the median seismic performance and employing the well‐known square‐root‐sum‐of‐squares rule to combine aleatory randomness and epistemic uncertainty. Copyright © 2009 John Wiley & Sons, Ltd.
Post‐earthquake bridge repair cost and repair time estimation methodology
Authors: Mackie Kevin R. , Wong John‐Michael , Stojadinović Božidar 
Published: July 2009

AbstractWhile structural engineers have traditionally focused on individual components (bridges, for example) of transportation networks for design, retrofit, and analysis, it has become increasingly apparent that the economic costs to society after extreme earthquake events are caused at least as much from indirect costs as direct costs due to individual structures. This paper describes an improved methodology for developing probabilistic estimates of repair costs and repair times that can be used for evaluating the performance of new bridge design options and existing bridges in preparation for the next major earthquake. The proposed approach in this paper is an improvement on previous bridge loss modeling studies—it is based on the local linearization of the dependence between repair quantities and damage states so that the resulting model follows a linear relationship between damage states and repair points. The methodology uses the concept of performance groups (PGs) that account for damage and repair of individual bridge components and subassemblies. The method is validated using two simple examples that compare the proposed method to simulation and previous methods based on loss models using a power–law relationship between repair quantities and damage. In addition, an illustration of the method is provided for a complete study on the performance of a common five‐span overpass bridge structure in California. Intensity‐dependent repair cost ratios (RCRs) and repair times are calculated using the proposed approach, as well as plots that show the disaggregation of repair cost by repair quantity and by PG. This provides the decision maker with a higher fidelity of data when evaluating the contribution of different bridge components to the performance of the bridge system, where performance is evaluated in terms of repair costs and repair times rather than traditional engineering quantities such as displacements and stresses. Copyright © 2009 John Wiley & Sons, Ltd.
Cost‐effective Synthesis of α‐LiAlO2 Powders for Molten Carbonate Fuel Cell Matrices
Authors: Choi H.‐J. , Lee J.‐J. , Hyun S.‐H. , Lim H.‐C. 
Published: July 2009

AbstractLithium aluminate (α‐/β‐LiAlO2) particles were fabricated using three methods. The first method used organic glycerin and triethylene glycol which functioned as a catalyst for fabrication of α‐LiAlO2 particles with Al(OH)3 and LiOH·H2O as the starting materials. As a result of the heat‐treatment of the starting materials, α‐/β‐LiAlO2 particles could be obtained. The amount of α‐LiAlO2 particles in α‐/β‐LiAlO2 increased slightly as more organics were added. Additionally, when synthesised α‐/β‐LiAlO2 particles were heat‐treated in a CO2 gas flow, β‐LiAlO2 was partially transformed to α‐LiAlO2. In the second method, molten salts (Li2/Na2/K2CO3) were used as a catalyst to fabricate α‐LiAlO2 as a major phase, however, this method requires a washing process which can produce unexpected impurities. In the third method, pure α‐LiAlO2 was obtained by heat‐treatment of cheap sources such as Li2CO3 and Al(OH)3 at 600–800 °C. The mean particle size (604 nm–11.85 μm) and the specific surface area (3.22–11.4 m2 g–1) of α‐LiAlO2 were suitable for reinforcing the matrix and tape casting. Lastly, this study examined the effect of CO2 for the synthesising of α‐LiAlO2 particles.
Trinomial or binomial: Accelerating American put option price on trees
Authors: Chan Jiun Hong , Joshi Mark , Tang Robert , Yang Chao 
Published: July 2009

AbstractWe investigate the pricing performance of eight trinomial trees and one binomial tree, which was found to be most effective in an earlier study, under 20 different implementation methodologies for pricing American put options. We conclude that the binomial tree, the Tian third‐order moment‐matching tree with truncation, Richardson extrapolation, and smoothing, performs better than the trinomial trees. © 2009 Wiley Periodicals, Inc. Jrl Fut Mark 29:826–839, 2009
Genomic aberrations in 80 cases of primary glioblastoma multiforme: Pathogenetic heterogeneity and putative cytogenetic pathways
Authors: Dahlback Hanne‐Sofie S. , Brandal Petter , Meling Torstein R. , Gorunova Ludmila , Scheie David , Heim Sverre 
Published: July 2009

AbstractScreening the whole glioblastoma multiforme (GBM) genome for aberrations is a good starting point when looking for molecular markers that could potentially stratify patients according to prognosis and optimal treatment. We investigated 80 primary untreated GBM using both G‐banding analysis and high‐resolution comparative genomic hybridization (HR‐CGH). Abnormal karyotypes were found in 83% of the tumors. The most common numerical chromosome aberrations were +7, −10, −13, −14, −15, +20, and −22. Structural abnormalities most commonly involved chromosomes 1 and 3, and the short arm of chromosome 9. HR‐CGH verified these findings and revealed additional frequent losses at 1p34‐36, 6q22‐27, and 19q12‐13 and gains of 3q26 and 12q13‐15. Although most karyotypes and gain/loss patterns were complex, there was also a distinct subset of tumors displaying simple karyotypic changes only. There was a statistically significant association between trisomy 7 and monosomy 10, and also between +7/−10 as putative primary aberrations and secondary losses of 1p, 9p, 13q, and 22q. The low number of tumors in the rarer histological tumor subgroups precludes definite conclusions, but there did not seem to be any clear‐cut cytogenetic‐pathological correlations, perhaps with the exception of ring chromosomes in giant cell glioblastomas. Our findings demonstrate that although GBM is a pathogenetically very heterogeneous group of diseases, distinct genomic aberration patterns exist. © 2009 Wiley‐Liss, Inc.
Alpine tectono‐metamorphic history of the continental units from Vardar zone: the Kopaonik Metamorphic Complex (Dinaric‐Hellenic belt, Serbia)
Authors: Zelic Mario , Levi Nicola , Malasoma Alessandro , Marroni Michele , Pandolfi Luca , Trivic Branislav 
Published: July 2009

AbstractThe easternmost zone of the Dinaric‐Hellenic belt is represented by the Vardar Zone, in which the Kopaonik Metamorphic Complex (KMC) is regarded as the lowermost unit. This complex is topped by the unmetamorphosed Brzece unit and is intruded by the Oligocene Kopaonik Intrusive complex. The KMC is characterized by a stratigraphy that includes metapelites and meta‐carbonates of Late Triassic age, associated with metabasites. It is characterized by a complex deformation history that comprises four phases: D1 to D4. The D1 phase structures occur only as relict structures, whereas the D2 phase structures are represented by isoclinal F2 folds, associated with a well‐developed S2 foliation. The estimated P‐T conditions for the D1 and D2 metamorphism are consistent with the upper greenschist facies. The D3 phase is characterized by west‐verging thrusts associated with upright folds. In contrast, the D4 phase is characterized by open folds (F4) associated with low‐angle normal faults. The D1 and D2 deformation phases developed during the shortening related to continental collision, whereas the subsequent D3 and D4 phases can be related to the progressive exhumation of the KMC. The D4 phase probably developed during extensional tectonics during and after emplacement of the Kopaonik Intrusive Complex. The data show that the continental units belonging to the Vardar zone had a long‐lived deformation history that was more complex that previously thought. Copyright © 2009 John Wiley & Sons, Ltd.
Optimal diffusion MRI acquisition for fiber orientation density estimation: An analytic approach
Authors: White Nathan S. , Dale Anders M. 
Published: July 2009

AbstractAn important challenge in the design of diffusion MRI experiments is how to optimize statistical efficiency, i.e., the accuracy with which parameters can be estimated from the diffusion data in a given amount of imaging time. In model‐based spherical deconvolution analysis, the quantity of interest is the fiber orientation density (FOD). Here, we demonstrate how the spherical harmonics (SH) can be used to form an explicit analytic expression for the efficiency of the minimum variance (maximally efficient) linear unbiased estimator of the FOD. Using this expression, we calculate optimal b‐values for maximum FOD estimation efficiency with SH expansion orders of L = 2, 4, 6, and 8 to be approximately b = 1,500, 3,000, 4,600, and 6,200 s/mm2, respectively. However, the arrangement of diffusion directions and scanner‐specific hardware limitations also play a role in determining the realizable efficiency of the FOD estimator that can be achieved in practice. We show how some commonly used methods for selecting diffusion directions are sometimes inefficient, and propose a new method for selecting diffusion directions in MRI based on maximizing the statistical efficiency. We further demonstrate how scanner‐specific hardware limitations generally lead to optimal b‐values that are slightly lower than the ideal b‐values. In summary, the analytic expression for the statistical efficiency of the unbiased FOD estimator provides important insight into the fundamental tradeoff between angular resolution, b‐value, and FOD estimation accuracy. Hum Brain Mapp, 2009. © 2009 Wiley‐Liss, Inc.