bluuebunny/crossref_metadata_2025_split huggingface dataset:
Estimation of Ion‐Pairing Constants in Plasticized Poly(vinyl chloride) Membranes Using Segmented Sandwich Membranes Technique
Authors: Egorov Vladimir V. , Lyaskovski Peter L. , Il'inchik Irina V. , Soroka Vera V. , Nazarov Valentine A. 
Published: July 2009

AbstractSegmented sandwich membrane method was used to determine ion‐pairing constants for four cationic sites: tris‐(2,3,4‐dodecyloxy)benzenetrimethylammonium, tris‐(2,3,4‐dodecyloxy)benzenedimethyloctylammonium, tris‐(2,3,4‐dodecyloxy)benzenemethyldioctylammonium, and dimethyldioctadecylammonium with chloride, bromide, nitrate, benzene sulfonate, trichloroacetate, thiocyanate, perchlorate and picrate, as well as ion‐pairing constants for two anionic sites: tetraphenylborate and tris‐(2,3,4‐octyloxy)benzenesulfonate with dimedrol, quinine, anapriline, and amantadine cations in poly(vinyl chloride) membranes plasticized with 2‐nitrophenyl octyl ether. Ion association constants of anions with quaternary ammonium sites regularly increase from picrate to chloride along with reduction of the anion radius and with improvement of site exchanger center steric accessibility. Ion association constants of amine cations with tris‐(2,3,4‐octyloxy)benzenesulfonate are several orders higher than those with tetraphenylborate and regularly increase from tertiary amine to primary one.
Non‐Gaussian state space models in decomposition of ice core time series in long and short time‐scales
Authors: Bojarova Jelena , Sundberg Rolf 
Published: July 2009

AbstractStatistical modelling of six time series of geological ice core chemical data from Greenland is discussed. We decompose the total variation into long time‐scale (trend) and short time‐scale variations (fluctuations around the trend), and a pure noise component. Too heavy tails of the short‐term variation makes a standard time‐invariant linear Gaussian model inadequate. We try non‐Gaussian state space models, which can be efficiently approximated by time‐dependent Gaussian models. In essence, these time‐dependent Gaussian models result in a local smoothing, in contrast to the global smoothing provided by the time‐invariant model. To describe the mechanism of this local smoothing, we utilise the concept of a local variance function derived from a heavy‐tailed density. The time‐dependent error variance expresses the uncertainty about the dynamical development of the model state, and it controls the influence of observations on the estimates of the model state components. The great advantage of the derived time‐dependent Gaussian model is that the Kalman filter and the Kalman smoother can be used as efficient computational tools for performing the variation decomposition. One of the main objectives of the study is to investigate how the distributional assumption on the model error component of the short time‐scale variation affects the decomposition. Copyright © 2009 John Wiley & Sons, Ltd.
Experimental study on earthquake‐induced pounding between structural elements made of different building materials
Authors: Jankowski Robert 
Published: July 2009

AbstractThe phenomenon of earthquake‐induced structural pounding has attracted the researchers' attention for several years now. The aim of this paper is to show the results of two experiments concerning interactions between elements made of different building materials, such as steel, concrete, timber and ceramic. The first experiment was conducted by dropping balls from different height levels onto a rigid surface, whereas the second one was focused on pounding‐involved response of two tower models excited on a shaking table. The results of the impact experiment show that the value of the coefficient of restitution depends substantially on the prior‐impact velocity as well as on the material used. Based on these results, the appropriate formulations have been suggested to be applied in the numerical simulations. The results of the shaking table tests show a considerable influence of the material used for colliding elements on the behaviour of structures during earthquakes. Copyright © 2009 John Wiley & Sons, Ltd.
Analysis of the behaviour of the structural concrete after the fire at the Windsor Building in Madrid
Authors: Menéndez E. , Vega L. 
Published: July 2009

AbstractThe analysis of the concrete subjected to high temperatures is usually undertaken by means of tests specifically designed and carried out in the laboratory, or by using theoretical approaches using standardized curves for theoretical fires.An analysis by different techniques has been carried out on structural concrete to real fire of Windsor Building in Madrid, which was severally damaged by a fire in 2005. These techniques are X‐ray diffraction, differential thermal and thermogravimetric analysis and backscattered electron microscopy with dispersive X‐ray microanalysis. Samples of the concrete were taken from different floors in the building and analyses were carried out at different depths starting from the surface exposed to the fire itself. The analysis allows the damaged area to be limited as well as situating the 500∘C isotherm in the concrete element.In accordance with the results obtained, the damage is limited to just a few centimeters from the surface exposed to the fire itself, in spite of its prolonged exposure to the fire. This would justify that the concrete has demonstrated a suitable resistant behaviour. Likewise, it can be deduced from the results obtained that the fire, to which the concrete was subjected, can be qualified as severe.Also, these results can confirm that the calculation hypothesis in the project is correct in relation to the fire resistance exigencies of the concrete. Copyright © 2009 John Wiley & Sons, Ltd.
3D tangentially injected swirling recirculating flow in a nozzle with a slotted‐tube—Effects of groove parameters
Authors: Guo Hui‐Fen , Chen Zhi‐Yong , Yu Chong‐Wen 
Published: July 2009

AbstractA numerical prediction for 3D swirling recirculating flow in an air‐jet spinning nozzle with a slotted‐tube is carried out with the realizable k–ε turbulence model. The effects of the groove parameters on the flow and yarn properties are investigated. The simulation results show that some factors, such as reverse flow upstream of the injector, vortex breakdown downstream of the injector, corner recirculation zone (CRZ) behind the step and vortex ring in the groove caused by the groove geometric variation, are significantly related to fluid flow, and consequently to yarn properties. With increasing groove height, the length of the CRZ increases, while the initial vortex ring in the groove decreases and a same direction rotating vortex forms in the bottom of the groove. Similarly, as the groove width increases, the extent of both vortex breakdown in downstream of the injectors and the vortex ring in the groove increases slightly, whereas the CRZ lengths in stream‐wise direction decrease. Some factors, such as the negative tangential velocities, the size of the vortex rings in the grooves and the CRZ, are constant for nozzles with different groove lengths. Copyright © 2009 John Wiley & Sons, Ltd.
The Nanocrystalline Nickel with Catalytic Properties on Methanol Oxidation in Alkaline Medium
Authors: Tehrani R. M. A. , Ab Ghani S. 
Published: July 2009

AbstractThe hexagonal closed packed (hcp) nanocrystalline nickel (Ni), with an average diameter of 9.7 ± 2.27 nm was deposited uniformly on composite graphite (CG) by the rapid scanning (6,500 mVs–1) voltammetry technique. The hcp‐nano Ni‐modified CG electrode was investigated for the catalytic oxidation of methanol in alkaline medium through the formation of NiOOH. A high anodic current was obtained at peak potential of +570 mV vs Ag/AgCl. Both the scan rate and the methanol concentration affected the oxidation of methanol. The results showed that catalytic activity had increased with decrease in Ni particle diameter. It was also shown that the hcp‐nano Ni/CG modified electrode was the most efficient catalyst in the oxidation of methanol.
Testing a Vapour‐fed PBI‐based Direct Ethanol Fuel Cell
Authors: Lobato J. , Cañizares P. , Rodrigo M. A. , Linares J. J. 
Published: July 2009

AbstractThis work is focused on the application and performance of a high temperature PBI‐based direct ethanol fuel cell, studying the influence of some operating variables such as the temperature, ethanol concentration and oxygen partial pressure. An increase in the temperature resulted in an improvement of the cell performance due to the enhanced electrodic kinetic and electrolyte conductivity. An ethanol/water weight ratio between 0.25 and 0.5 was found to be suitable for providing both enough water and fuel availability to make the ethanol oxidation possible. Measurements of the ethanol crossover at different temperatures and concentrations were carried out. An intermittent lifetime test showed that the cell, after several hours, was able to reach stability. Moreover, its performance was completely reversible with no perceptible losses for 7 days. Finally, tests using bio‐ethanol as fuel were performed, with no significant power losses. This final feature is of special interest from a practical ‘green' point of view.
Long Term Testing in Continuous Mode of HT‐PEMFC Based H3PO4/PBI Celtec‐P MEAs for μ‐CHP Applications
Authors: Moçotéguy Ph. , Ludwig B. , Scholta J. , Barrera R. , Ginocchio S. 
Published: July 2009

AbstractSingle cell and 500 We stack integrating Celtec P1000 MEAs were operated in continuous mode at 0.4 A cm–2 and 160 °C, under simulated reformate and air. Single cell's ohmic resistivity was almost unaffected by 1,100 h of ageing but the cell progressively switched from a cathodic to an anodic mass transfer limited operation. The stack was operated for 658 h, exhibiting the same behaviour and an additional increase in cell voltage distribution heterogeneity. CO2 proved to have negligible effect on performances but performance losses induced by ageing are doubled in the presence of CO. Post‐testing experiments revealed that anode electrochemical active area was dramatically decreased and that platinum content was also decreased. Finally, results showed that a convenient shut‐down procedure could prevent or limit degradations associated with storage.
Determination of the Potentiostatic Stability of PEMFC Electro Catalysts at Elevated Temperatures
Authors: Dam V. A. T. , Jayasayee K. , de Bruijn F. A. 
Published: July 2009

AbstractThe electrochemical stability of platinum on carbon catalyst (Hispec™ 4000, Johnson Matthey) has been investigated predominantly at constant potentials ranging from 0.95 to 1.25 V at elevated temperatures. By combining a quartz crystal microbalance (QCM) with electrochemical techniques, dynamic insight is obtained on the oxidation and corrosion of both platinum and carbon during potentiostatic hold. From the cyclic voltammetry (CV) data, it can be concluded that at all conditions, the platinum surface area decreases when Pt on carbon catalysts are exposed to a constant potential of 1.05 to 1.25 V. Under the applied conditions, this loss of surface area is primarily caused by the dissolution of platinum.Both the QCM as well as on‐line electrochemical mass spectrometry (OLEMS) experiments show that the corrosion of carbon is catalysed by the presence of platinum at 80 °C, as long as the platinum surface is not passivated by an oxide layer.
Microstructure and Microfabrication Considerations for Self‐Supported On‐Chip Ultra‐Thin Micro‐Solid Oxide Fuel Cell Membranes
Authors: Lai B.‐K. , Xiong H. , Tsuchiya M. , Johnson A. C. , Ramanathan S. 
Published: July 2009

AbstractLa0.6Sr0.4Co0.8Fe0.2O3 – δ (LSCF) has been sputtered on bare Si and Si3N4 and yttria‐stabilised zirconia (YSZ) thin films to investigate annealing temperature‐ and thickness‐dependent microstructure and functional properties, as well as their implications for designing failure‐resistant micro‐solid oxide fuel cell (μSOFC) membranes. The LSCF thin films crystallise in the 400–450 °C range; however, after annealing in the 600–700 °C range, cracks are observed. The formation of cracks is also thickness‐dependent. High electrical conductivity, ∼520 Scm–1 at 600 °C, and low activation energy, ∼0.13 eV, in the 400–600 °C range, are still maintained for LSCF films as thin as 27 nm. Based on these studies, a strong correlation between microstructure and electrical conductivity has been observed and an annealing temperature‐thickness design space that is complementary to temperature‐stress design space has been proposed for designing reliable membranes using sputtered LSCF thin films. Microfabrication approaches that maintain the highest possible surface and interface quality of heterostructured membranes have been carefully examined. By taking advantage of the microstructure, microfabrication and geometrical structural considerations, we were able to successfully fabricate large‐area, self‐supported membranes. These results are also relevant to conventional or grid‐supported SOFC membranes using ultrathin nanocrystalline cathodes and μSOFCs using cathode thin films other than LSCF.
The value of mortgage prepayment and default options
Authors: Chen Yong , Connolly Michael , Tang Wenjin , Su Tie 
Published: July 2009

AbstractWe use an implicit alternating direction numerical procedure to estimate the value of a fixed‐rate mortgage (FRM) with embedded default and prepayment options. The value of FRMs depends on interest rates, the house value, and mortgage maturity. Our numerical results suggest that the joint option value of prepayment and default is considerably high, even at loan origination. We extend the model to include prepayment penalties in FRM valuation. © 2009 Wiley Periodicals, Inc. Jrl Fut Mark 29:840–861, 2009
An explicitly solvable multi‐scale stochastic volatility model: Option pricing and calibration problems
Authors: Fatone Lorella , Mariani Francesca , Recchioni Maria Cristina , Zirilli Francesco 
Published: July 2009

AbstractWe introduce an explicitly solvable multiscale stochastic volatility model that generalizes the Heston model. The model describes the dynamics of an asset price and of its two stochastic variances using a system of three Ito stochastic differential equations. The two stochastic variances vary on two distinct time scales and can be regarded as auxiliary variables introduced to model the dynamics of the asset price. Under some assumptions, the transition probability density function of the stochastic process solution of the model is represented as a one‐dimensional integral of an explicitly known integrand. In this sense the model is explicitly solvable. We consider the risk‐neutral measure associated with the proposed multiscale stochastic volatility model and derive formulae to price European vanilla options (call and put) in the multiscale stochastic volatility model considered. We use the thus‐obtained option price formulae to study the calibration problem, that is to study the values of the model parameters, the correlation coefficients of the Wiener processes defining the model, and the initial stochastic variances implied by the “observed” option prices using both synthetic and real data. In the analysis of real data, we use the S&P 500 index and to the prices of the corresponding options in the year 2005. The web site http://www.econ.univpm.it/recchioni/finance/w7 contains some auxiliary material including some animations that helps the understanding of this article. A more general reference to the work of the authors and their coauthors in mathematical finance is the web site http://www.econ.univpm.it/recchioni/finance. © 2009 Wiley Periodicals, Inc. Jrl Fut Mark 29:862–893, 2009
Identifying the molecular signature of the interstitial deletion 7q subgroup of uterine leiomyomata using a paired analysis
Authors: Hodge Jennelle C. , Park Peter J. , Dreyfuss Jonathan M. , Assil‐Kishawi Iman , Somasundaram Priya , Semere Luwam G. , Quade Bradley J. , Lynch Allison M. , Stewart Elizabeth A. , Morton Cynthia C. 
Published: July 2009

AbstractUterine leiomyomata (UL), the most common neoplasm in reproductive‐age women, have recurrent cytogenetic abnormalities including interstitial deletion of 7q. To develop a molecular signature, matched del(7q) and non‐del(7q) tumors identified by FISH or karyotyping from 11 women were profiled with expression arrays. Our analysis using paired t tests demonstrates this matched design is critical to eliminate the confounding effects of genotype and environment that underlie patient variation. A gene list ordered by genome‐wide significance showed enrichment for the 7q22 target region. Modification of the gene list by weighting each sample for percent of del(7q) cells to account for the mosaic nature of these tumors further enhanced the frequency of 7q22 genes. Pathway analysis revealed two of the 19 significant functional networks were associated with development and the most represented pathway was protein ubiquitination, which can influence tumor development by stabilizing oncoproteins and destabilizing tumor suppressor proteins. Array CGH (aCGH) studies determined the only consistent genomic imbalance was deletion of 9.5 megabases from 7q22‐7q31.1. Combining the aCGH data with the del(7q) UL mosaicism‐weighted expression analysis resulted in a list of genes that are commonly deleted and whose copy number is correlated with significantly decreased expression. These genes include the proliferation inhibitor HPB1, the loss of expression of which has been associated with invasive breast cancer, as well as the mitosis integrity‐maintenance tumor suppressor RINT1. This study provides a molecular signature of the del(7q) UL subgroup and will serve as a platform for future studies of tumor pathogenesis. © 2009 Wiley‐Liss, Inc.
Colocalization of somatic and meiotic double strand breaks near the Myc oncogene on mouse chromosome 15
Authors: Ng Siemon H. , Maas Sarah A. , Petkov Petko M. , Mills Kevin D. , Paigen Kenneth 
Published: July 2009

AbstractBoth somatic and meiotic recombinations involve the repair of DNA double strand breaks (DSBs) that occur at preferred locations in the genome. Improper repair of DSBs during either mitosis or meiosis can lead to mutations, chromosomal aberration such as translocations, cancer, and/or cell death. Currently, no model exists that explains the locations of either spontaneous somatic DSBs or programmed meiotic DSBs or relates them to each other. One common class of tumorigenic translocations arising from DSBs is chromosomal rearrangements near the Myc oncogene. Myc translocations have been associated with Burkitt lymphoma in humans, plasmacytoma in mice, and immunocytoma in rats. Comparing the locations of somatic and meiotic DSBs near the mouse Myc oncogene, we demonstrated that the placement of these DSBs is not random and that both events clustered in the same short discrete region of the genome. Our work shows that both somatic and meiotic DSBs tend to occur in proximity to each other within the Myc region, suggesting that they share common originating features. It is likely that some regions of the genome are more susceptible to both somatic and meiotic DSBs, and the locations of meiotic hotspots may be an indicator of genomic regions more susceptible to DNA damage. © 2009 Wiley‐Liss, Inc.
Are there any more ovarian tumor suppressor genes? A new perspective using ultra high‐resolution copy number and loss of heterozygosity analysis
Authors: Gorringe Kylie L. , Ramakrishna Manasa , Williams Louise H. , Sridhar Anita , Boyle Samantha E. , Bearfoot Jennifer L. , Li Jason , Anglesio Michael S. , Campbell Ian G. 
Published: July 2009

AbstractOvarian cancer is characterized by complex genetic alterations, including copy number loss and copy number‐neutral loss of heterozygosity (LOH). These alterations are assumed to represent the “second hit” of the underlying tumor suppressor gene (TSG), however, relative to the number of LOH hotspots reported, few ovarian TSGs have been identified. We conducted a high‐resolution LOH analysis using SNP arrays (500K and SNP6.0) of 106 primary ovarian tumors of various histological subtypes together with matching normal DNA. LOH was detected in at least 35% of samples on chromosomes 17, 19p, 22q, Xp, 13q, 8p, 6q, 4q, 5q, 1p, 16q, and 9q with a median minimal region of overlap of only 300 kb. Subtype‐specific differences in LOH frequency were noted, particularly for mucinous cases. We also identified 192 somatic homozygous deletions (HDs). Recurrent HDs targeted known TSGs such as CDKN2A (eight samples), RB1 (five samples), and PTEN (three samples). Additional recurrent HDs targeted 16 candidate TSGs near minimal regions of LOH on chromosomes 17, 13, 8p, 5q, and X. Given the importance of HDs in inactivating known genes, these candidates are highly likely to be ovarian TSGs. Our data suggest that the poor success of previous LOH studies was due to the inability of previous technology to resolve complex genomic alterations and distinguish true LOH from allelic imbalance. This study shows that recurrent regions of LOH and HD frequently align with known TSGs suggesting that LOH analysis remains a valid approach to discovering new candidates. © 2009 Wiley‐Liss, Inc.
Pathological amygdala activation during working memory performance: Evidence for a pathophysiological trait marker in bipolar affective disorder
Authors: Gruber Oliver , Tost Heike , Henseler Ilona , Schmael Christine , Scherk Harald , Ende Gabriele , Ruf Matthias , Falkai Peter , Rietschel Marcella 
Published: July 2009

AbstractRecent evidence suggests that deficits of working memory may be a promising neurocognitive endophenotype of bipolar affective disorder. However, little is known about the neurobiological correlates of these deficits. The aim of this study was to determine possible pathophysiological trait markers of bipolar disorder in neural circuits involved in working memory. Functional magnetic resonance imaging was performed in 18 euthymic bipolar patients and 18 matched healthy volunteers using two circuit‐specific experimental tasks established by prior systematic neuroimaging studies of working memory. Both euthymic bipolar patients and healthy controls showed working memory‐related brain activations that were highly consistent with findings from previous comparable neuroimaging studies in healthy subjects. While these patterns of brain activation were completely preserved in the bipolar patients, only the patients exhibited activation of the right amygdala during the articulatory rehearsal task. In the same task, functional activation in right frontal and intraparietal cortex and in the right cerebellum was significantly enhanced in the patients. These findings indicate that the right amygdala is pathologically activated in euthymic bipolar patients during performance of a circuit‐specific working memory task (articulatory rehearsal). This pathophysiological abnormality appears to be a trait marker in bipolar disorders that can be observed even in the euthymic state and that seems to be largely independent of task performance and medication. Hum Brain Mapp, 2010. © 2009 Wiley‐Liss, Inc.