bluuebunny/crossref_metadata_2025 huggingface dataset:
Creation of Stabilized Electrochromic Materials by Taking Advantage of Azulene Skeletons
Authors: Ito Shunji , Morita Noboru
Published: July 2009

The 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

Acetals 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

The 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

In 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

Micropipette 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

Ion 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

Cyclic 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

A 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

Water 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

An 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

We 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

Incremental 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

While 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

Lithium 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

We 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

Screening 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

The 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

An 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.
An efficient synthesis of α‐Amino phosphonates using silica sulfuric acid as a heterogeneous catalyst
Authors: Maghsoodlou Malek Taher , Khorassani Sayyed Mostafa Habibi , Hazeri Nourollah , Rostamizadeh Mohsen , Sajadikhah Seyed Sajad , Shahkarami Zahra , Maleki Nariman
Published: July 2009

α‐Amino phosphonates were obtained in a one‐pot, simple, and efficient method from the reaction between aldehyde, aniline, trialkyl phosphite, and silica sulfuric acid as a catalyst in acetonitrile at room temperature. © 2009 Wiley Periodicals, Inc. Heteroatom Chem 20:316–318, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20543
Axonal sodium channel distribution shapes the depolarized action potential threshold of dentate granule neurons
Authors: Kress Geraldine J. , Dowling Margaret J. , Eisenman Lawrence N. , Mennerick Steven
Published: July 2009

Intrinsic excitability is a key feature dictating neuronal response to synaptic input. Here we investigate the recent observation that dentate granule neurons exhibit a more depolarized voltage threshold for action potential initiation than CA3 pyramidal neurons. We find no evidence that tonic GABA currents, leak or voltage‐gated potassium conductances, or the expression of sodium channel isoform differences can explain this depolarized threshold. Axonal initial segment voltage‐gated sodium channels, which are dominated by the NaV1.6 isoform in both cell types, distribute more proximally and exhibit lower overall density in granule neurons than in CA3 neurons. To test possible contributions of sodium channel distributions to voltage threshold and to test whether morphological differences participate, we performed simulations of dentate granule neurons and of CA3 pyramidal neurons. These simulations revealed that cell morphology and sodium channel distribution combine to yield the characteristic granule neuron action potential upswing and voltage threshold. Proximal axon sodium channel distribution strongly contributes to the higher voltage threshold of dentate granule neurons for two reasons. First, action potential initiation closer to the somatodendritic current sink causes the threshold of the initiating axon compartment to rise. Second, the proximity of the action potential initiation site to the recording site causes somatic recordings to more faithfully reflect the depolarized threshold of the axon than in cells like CA3 neurons, with distally initiating action potentials. Our results suggest that the proximal location of axon sodium channels in dentate granule neurons contributes to the intrinsic excitability differences between DG and CA3 neurons and may participate in the low‐pass filtering function of dentate granule neurons. © 2009 Wiley‐Liss, Inc.
Blockade of insulin‐like growth factor‐I has complex effects on structural plasticity in the hippocampus
Authors: Glasper Erica R. , Llorens‐Martin Maria V. , Leuner Benedetta , Gould Elizabeth , Trejo Jose L.
Published: July 2009

Physical exercise enhances adult neurogenesis in the hippocampus. Running induces the uptake of blood insulin‐like growth factor‐I (IGF‐I) into the brain. A causal link between these two phenomena has been reported; running‐induced increases in adult neurogenesis can be blocked by peripheral infusion of anti‐IGF‐I. Running also alters other aspects of hippocampal structure, including dendritic spine density. It remains unclear, however, whether these effects are also mediated through an IGF‐I mechanism. To examine this possibility, we blocked peripheral IGF‐I and examined adult neurogenesis and dendritic spine density in treadmill running mice. Two weeks of running resulted in an increase in cell proliferation in the dentate gyrus (DG) as well as an increase in dendritic spine density on DG granule cells and basal dendrites of CA1 pyramidal neurons, while having no effect on apical or basal dendritic spine density of CA3 pyramidal neurons. IGF‐I blockade reduced cell proliferation in both sedentary and running mice, but by contrast, this treatment had no effect on granule cell or CA3 pyramidal cell dendritic spine density in sedentary or running mice. However, IGF‐I antibody treatment seemed to prevent the running‐induced increase in spine density on basal dendrites of CA1 pyramidal cells. These results suggest that IGF‐I exerts a complex influence over hippocampal structure and that its effects are not restricted to those induced by running. © 2009 Wiley‐Liss, Inc.
Mammalian polyamine metabolism and function
Authors: Pegg Anthony E.
Published: July 2009

Polyamines are ubiquitous small basic molecules that play multiple essential roles in mammalian physiology. Their cellular content is highly regulated and there is convincing evidence that altered metabolism is involvement in many disease states. Drugs altering polyamine levels may therefore have a variety of important targets. This review will summarize the current state of understanding of polyamine metabolism and function, the regulation of polyamine content, and heritable pathological conditions that may be derived from altered polyamine metabolism. © 2009 IUBMB IUBMB Life 61(9): 880–894, 2009
Long‐run relations in European electricity prices
Authors: Bosco Bruno , Parisio Lucia , Pelagatti Matteo , Baldi Fabio
Published: July 2009

This paper analyses the interdependencies existing in wholesale electricity prices in six major European countries. The results of a robust multivariate long‐run dynamic analysis reveal the presence of four highly integrated central European markets (France, Germany, the Netherlands and Austria). The trend shared by these four electricity markets appears to be common also to gas prices, but not to oil prices. The existence of a common long‐term dynamics among electricity prices and between electricity prices and gas prices can be explained by the similarity of the market design across Europe and by the same marginal generation technology. Since standard unit root and cointegration tests are not robust to the peculiar characteristics of electricity prices time series, we also develop a battery of robust inference procedures that should assure the reliability of our results. Copyright © 2009 John Wiley & Sons, Ltd.
Forecast encompassing tests and probability forecasts
Authors: Clements Michael P. , Harvey David I.
Published: July 2009

We consider tests of forecast encompassing for probability forecasts, for both quadratic and logarithmic scoring rules. We propose test statistics for the null of forecast encompassing, present the limiting distributions of the test statistics, and investigate the impact of estimating the forecasting models' parameters on these distributions. The small‐sample performance is investigated, in terms of small numbers of forecasts and model estimation sample sizes. We show the usefulness of the tests for the evaluation of recession probability forecasts from logit models with different leading indicators as explanatory variables, and for evaluating survey‐based probability forecasts. Copyright © 2009 John Wiley & Sons, Ltd.
Effects of resveratrol analogs on steroidogenesis and mitochondrial function in rat Leydig cells in vitro
Authors: Svechnikov Konstantin , Spatafora Carmela , Svechnikova Irina , Tringali Corrado , Söder Olle
Published: July 2009

Resveratrol and its analogs are considered to be a promising drug candidate for treatment of cancer and different age‐associated diseases. In the present study we have investigated the effects of resveratrol and its synthetic analogs on steroidogenesis and mitochondrial function in primary cultures of rat Leydig cells. Our findings indicate that resveratrol and its analogs structure‐dependently attenuated hCG‐activated steroidogenesis in Leydig cells through suppression of the expression of steroidogenic acute regulatory protein and cytochrome P450c17. 3,5‐Diacetyl resveratrol was observed to modulate mitochondrial function in Leydig cells, suppressing polarization of inner mitochondrial membrane, and 3,4,4′‐trimethoxystilbene stimulated the overall activity of intracellular reductases involved in the reduction of WST‐1 to formazan. Thus, the inhibitory actions of resveratrol analogs on steroidogenesis in Leydig cells indicate novel mechanisms of action of these compounds, which may be of potential therapeutic interest, where suppression of androgen action is needed. Copyright © 2009 John Wiley & Sons, Ltd.
Minireview: does in‐vitro testing of oximes help predict their in‐vivo action after paraoxon exposure?
Authors: Lorke D. E. , Petroianu G. A.
Published: July 2009

K‐oximes have recently been developed in the search for efficacious broad‐band reactivators of acetylcholinesterase (AChE) inhibited by organophosphorus compounds (OPC). Before clinical use, their toxicity and efficacy need to be assessed, and there is clear demand for simple in vitro tests that can predict in vivo performance. This article summarizes our in vitro data obtained for conventional and experimental oximes in human and rat blood exposed to the OPC paraoxon and correlates them with our in vivo results. The intrinsic AChE inhibitory activity of oximes, as reflected by their in vitro IC50, is strongly correlated with their LD50 (rat): oximes with a high IC50 (K‐27, K‐48, pralidoxime and obidoxime) also show a high LD50 and are thus relatively non‐toxic, whereas oximes K‐105, K‐108 and K‐113 have a low IC50, a low LD50 and are far more toxic. The IC50 is also correlated with the in vivo capacity to protect from paraoxon‐induced mortality: oximes with a higher IC50 reduce the relative risk of death more. In contrast, the protective ability as assessed in vitro by the slope of the IC50 shift (tanα), is not correlated with in vivo protection from paraoxon‐induced mortality: the best in vivo protectors (K‐27 and K‐48) show a much lower tanα value (around 2) than K‐110 and K‐113 (tanα around 10), which hardly reduce the relative risk of death after paraoxon exposure. The partition coefficient logP of the individual oximes is inversely correlated with their IC50 and with their LD50 and is therefore an indicator of toxicity: strongly hydrophilic oximes tend to be less toxic than less hydrophilic ones. These data highlight the good predictive value of in vitro IC50 testing for in vivo toxicity and the limited practical significance of in vitro assessment of protective potency. Copyright © 2009 John Wiley & Sons, Ltd.
Targeted optical injection of gold nanoparticles into single mammalian cells
Authors: McDougall Craig , Stevenson David J. , Brown Christian T. A. , Gunn‐Moore Frank , Dholakia Kishan
Published: July 2009

We present an all optical technique for the targeted delivery of single 100 nm diameter gold nanoparticles into a specified region of the interior of an individual mammalian cell through a combination of optical tweezing and optical injection. The internalisation of the nanoparticle is verified by confocal laser scanning microscopy and confocal laser scanning reflectance microscopy. This represents the first time that nano sized particles have been tweezed and optically injected into mammalian cells using only light, and provides a novel methodology for internalising nanosphere based biosensors within specific intracellular regions of a mammalian cell. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Graph‐theoretical identification of dissociation pathways on free energy landscapes of biomolecular interaction
Authors: Wang Ling , Stumm Boris , Helms Volkhard
Published: July 2009

Biomolecular association and dissociation reactions take place on complicated interaction free energy landscapes that are still very hard to characterize computationally. For large enough distances, though, it often suffices to consider the six relative translational and rotational degrees of freedom of the two particles treated as rigid bodies. Here, we computed the six‐dimensional free energy surface of a dimer of water‐soluble alpha‐helices by scanning these six degrees of freedom in about one million grid points. In each point, the relative free energy difference was computed as the sum of the polar and nonpolar solvation free energies of the helix dimer and of the intermolecular coulombic interaction energy. The Dijkstra graph algorithm was then applied to search for the lowest cost dissociation pathways based on a weighted, directed graph, where the vertices represent the grid points, the edges connect the grid points and their neighbors, and the weights are the reaction costs between adjacent pairs of grid points. As an example, the configuration of the bound state was chosen as the source node, and the eight corners of the translational cube were chosen as the destination nodes. With the strong electrostatic interaction of the two helices giving rise to a clearly funnel‐shaped energy landscape, the eight lowest‐energy cost pathways coming from different orientations converge into a well‐defined pathway for association. We believe that the methodology presented here will prove useful for identifying low‐energy association and dissociation pathways in future studies of complicated free energy landscapes for biomolecular interaction. © 2009 Wiley Periodicals, Inc. J Comput Chem, 2010
On the use of symmetry in the ab initio quantum mechanical simulation of nanotubes and related materials
Authors: Noel Yves , D'arco Philippe , Demichelis Raffaella , Zicovich‐Wilson Claudio M. , Dovesi Roberto
Published: July 2009

Nanotubes can be characterized by a very high point symmetry, comparable or even larger than the one of the most symmetric crystalline systems (cubic, 48 point symmetry operators). For example, N = 2n rototranslation symmetry operators connect the atoms of the (n,0) nanotubes. This symmetry is fully exploited in the CRYSTAL code. As a result, ab initio quantum mechanical large basis set calculations of carbon nanotubes containing more than 150 atoms in the unit cell become very cheap, because the irreducible part of the unit cell reduces to two atoms only. The nanotube symmetry is exploited at three levels in the present implementation. First, for the automatic generation of the nanotube structure (and then of the input file for the SCF calculation) starting from a two‐dimensional structure (in the specific case, graphene). Second, the nanotube symmetry is used for the calculation of the mono‐ and bi‐electronic integrals that enter into the Fock (Kohn‐Sham) matrix definition. Only the irreducible wedge of the Fock matrix is computed, with a saving factor close to N. Finally, the symmetry is exploited for the diagonalization, where each irreducible representation is separately treated. When M atomic orbitals per carbon atom are used, the diagonalization computing time is close to Nt, where t is the time required for the diagonalization of each 2M × 2M matrix. The efficiency and accuracy of the computational scheme is documented. © 2009 Wiley Periodicals, Inc. J Comput Chem, 2010
Theoretical study on nonlinear optical properties of the Li+[calix[4]pyrrole]Li−dimer, trimer and its polymer with diffuse excess electrons
Authors: Yu Guang Tao , Chen Wei , Gu Feng Long , Aoki Yuriko
Published: July 2009

The static (hyper)polarizabilities of the dimer and trimer with diffuse excess electrons, [Li+[calix[4]pyrrole]Li−]n, are firstly investigated by the DFT(B3LYP) method in detail. For the dimer and trimer, a Li atom inside each calix[4]pyrrole unit is ionized to form a diffuse excess electron. The results show that the dimer and trimer containing two and three excess electrons, respectively, have very large first hyperpolarizablities as 2.3 × 104 and 4.0 × 104 au, which are 30 and 40 times larger than that of the corresponding [calix[4]pyrrole]n (n = 2, 3) without Li atom. Also, β values of dimer and trimer are twice and four times as large as that of monomer containing one excess electron. Obviously, not only excess electron but also the number of excess electron plays an important role in increasing the first hyperpolarizability. Moreover, the (hyper)polarizabilities of the [Li+[calix[4]pyrrole]Li−]n polymer are investigated at ab initio level by using the elongation finite‐field (elongation FF) method. All the oligomers of the [Li+[calix[4]pyrrole]Li−]n with many excess electrons exhibit very large first hyperpolarizability and large second hyperpolarizability. The present investigation shows that by introducing several and more excess electrons into the nonlinear optical (NLO) materials will be an important strategy for improving their NLO properties, which will be helpful for design of NLO materials. © 2009 Wiley Periodicals, Inc. J Comput Chem, 2010
Osteology of the Graveldiver Scytalina cerdale (Perciformes: Zoarcoidei: Scytalinidae)
Authors: Hilton Eric J.
Published: July 2009

The Graveldiver, Scytalina cerdale, is a small, poorly known burrowing fish from the intertidal and subtidal zones of the west coast of North America, ranging from south‐central California to Alaska. This is the sole member of the family Scytalinidae, which is included in the Zoarcoidei. Although it was described over 120 years ago, it is rare in natural history collections and its anatomy is only imperfectly known. This article describes and illustrates the skeletal anatomy of S. cerdale based on newly prepared cleared and stained specimens. Many points of its anatomy are clarified or corrected (e.g., presence of the intercalars and ribs, in contrast to their reported absence) or described for the first time (e.g., structure of its gill‐arches). Previous hypotheses of its systematic placement within the Zoarcoidei are discussed. On the basis of preliminary comparisons, S. cerdale may have phylogenetic affinity with at least some members of the family Stichaeidae (e.g., Xiphister). However, further study is needed on the anatomy and inter‐relationships of the families of the Zoarcoidei before any conclusions can be made. J. Morphol., 2009. © 2009 Wiley‐Liss, Inc.
Cervids with different vocal behavior demonstrate different viscoelastic properties of their vocal folds
Authors: Riede Tobias , Lingle Susan , Hunter Eric J. , Titze Ingo R.
Published: July 2009

The authors test the hypothesis that vocal fold morphology and biomechanical properties covary with species‐specific vocal function. They investigate mule deer (Odocoileus hemionus) vocal folds, building on, and extending data on a related cervid, the Rocky Mountain elk (Cervus elaphus nelsoni). The mule deer, in contrast to the elk, is a species with relatively little vocal activity in adult animals. Mule deer and elk vocal folds show the typical three components of the mammalian vocal fold (epithelium, lamina propria and thyroarytenoid muscle). The vocal fold epithelium and the lamina propria were investigated in two sets of tensile tests. First, creep rupture tests demonstrated that ultimate stress in mule deer lamina propria is of the same magnitude as in elk. Second, cyclic loading tests revealed similar elastic moduli for the vocal fold epithelium in mule deer and elk. The elastic modulus of the lamina propria is also similar between the two species in the low‐strain region, but differs at strains larger than 0.3. Sex differences in the stress–strain response, which have been reported for elk and human vocal folds, were not found for mule deer vocal folds. The laminae propriae in mule deer and elk vocal folds are comparatively large. In general, a thick and uniformly stiff lamina propria does not self‐oscillate well, even when high subglottic pressure is applied. If the less stiff vocal fold seen in elk is associated with a differentiated lamina propria it would allow the vocal fold to vibrate at high tension and high subglottic pressure. The results of this study support the hypothesis that viscoelastic properties of vocal folds varies with function and vocal behavior. J. Morphol., 2010. © 2009 Wiley‐Liss, Inc.
Overexpression of the PDZ1 domain of PSD‐95 diminishes ischemic brain injury via inhibition of the GluR6·PSD‐95·MLK3 pathway
Authors: Hu Shu‐Qun , Zhu Jie , Pei Dong‐Sheng , Zong Yan‐Yan , Yan Jing‐Zhi , Hou Xiao‐Yu , Zhang Guang‐Yi
Published: July 2009

Recent studies have shown that kainate (KA) receptors are involved in neuronal cell death induced by seizure, which is mediated by the GluR6·PSD‐95·MLK3 signaling module and subsequent JNK activation. In our previous studies, we demonstrated the neuroprotective role of a GluR6 c‐terminus containing peptide against KA or cerebral ischemia‐induced excitotoxicity in vitro and in vivo. Here, we first report that overexpression of the PDZ1 domain of PSD‐95 protein exerts a protective role against neuronal death induced by cerebral ischemia‐reperfusion in vivo and can prevent neuronal cell death induced by oxygen‐glucose deprivation. Further studies show that overexpression of PDZ1 can perturb the interaction of GluR6 with PSD‐95 and suppress the assembly of the GluR6·PSD‐95·MLK3 signaling module and therefore inhibit JNK activation. Thus, it not only inhibits phosphorylation of c‐Jun and down‐regulates Fas ligand expression but also inhibits phosphorylation of 14‐3‐3 and decreases Bax translocation to mitochondria, decreases the release of cytochrome c, and decreases caspase‐3 activation. Overall, the essential role of the PDZ1 domain of PSD‐95 in apoptotic cell death in neurons provides an experimental foundation for gene therapy of neurodegenerative diseases with overexpression of the PDZ1 domain. © 2009 Wiley‐Liss, Inc.
Tissue neogenesis and STRO‐1 expression in immature and mature articular cartilage
Authors: Otsuki Shuhei , Grogan Shawn P. , Miyaki Shigeru , Kinoshita Mitsuo , Asahara Hiroshi , Lotz Martin K.
Published: July 2009

This study determined the potential for neotissue formation and the role of STRO‐1+ cells in immature versus mature articular cartilage. Cartilage explants from immature and mature bovine knee joints were cultured for up to 12 weeks and stained with safranin‐O, for type II collagen and STRO‐1. Bovine chondrocyte pellet cultures and murine knee joints at the age of 2 weeks and 3 months, and surgically injured cartilage, were analyzed for changes in STRO‐1 expression patterns. Results show that immature explants contained more STRO‐1+ cells than mature explants. After 8 weeks in culture, immature explants showed STRO‐1+ cell proliferation and newly formed tissue, which contained glycosaminoglycan and type II collagen. Mature cartilage explants showed only minimal cell expansion and neotissue formation. Pellet cultures with chondrocytes from immature cartilage showed increased glycosaminoglycan synthesis and STRO‐1+ staining, as compared to pellets with mature chondrocytes. The frequency of STRO‐1+ cells in murine knee joints significantly declined with joint maturation. Following surgical injury, immature explants had higher potential for tissue repair than mature explants. In conclusion, these findings suggest that the high percentage of STRO‐1+ cells in immature cartilage changes with joint maturation. STRO‐1+ cells have the potential to form new cartilage spontaneously and after tissue injury. © 2009 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 28:96–102, 2010