bluuebunny/crossref_metadata_2025 huggingface dataset:
Occupational coke oven emissions exposure and risk of abnormal liver function: modifications of body mass index and hepatitis virus infection
Authors: Hu Y , Chen B , Qian J , Jin L , Jin T , Lu D
Published: September 2009

Objectives

Occupational coke oven emissions (COEs) have been considered an important health issue. However, there are no conclusive data on human hepatic injury due to COE exposure. The association of COE exposure with liver function was explored and the effects of modification of potential non-occupational factors were assessed.

Methods

705 coke oven workers and 247 referents were investigated. Individual cumulative COE exposure was quantitatively estimated. Serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), γ-glutamyl transferase, alkaline phosphatase, hepatitis B surface antigen and anti-hepatitis C antibody were measured.

Results

Among those with high COE exposure, the adjusted ORs of abnormal ALT and AST were 5.23 (95% CI 2.66 to 10.27) and 1.95 (95% CI 1.18 to 3.52), respectively. Overweight individuals (body mass index (BMI) ≥25 kg/m2) with high COE exposure had elevated risks of abnormal ALT (adjusted OR 23.93, 95% CI 8.73 to 65.62) and AST (adjusted OR 5.18, 95% CI 2.32 to 11.58). Risk of liver damage in hepatitis B virus- or hepatitis C virus-positive individuals with COE exposure was also elevated.

Conclusions

Long-term exposure to COE increases the risk of liver dysfunction, which is more prominent among those with higher BMI and hepatitis virus infection. The risk assessment of liver damage associated with COE exposure should take BMI and hepatitis virus infection into consideration.
Variable Natural Mortality Rates Inflate Variance of Recruitments Estimated from Virtual Population Analysis (VPA)
Authors: Lapointe Michael F. , Peterman Randall M. , Rothschild Brian J.
Published: September 2009

We used a simulation model to determine whether estimates offish recruitment obtained from virtual population analysis (VPA) (1) have the correct interannual variability and (2) yield high statistical power (>0.8) when correlated with an environmental factor, given that the "true" instantaneous adult natural mortality rate (M) likely varies over time but a constant M is used in VPA (MVPA). Under such circumstances, VPA exaggerates variability in recruitment, which reduces the probability of correctly detecting environmental correlates with recruitment. The magnitude of these effects increases with increases in (1) the absolute value of the true mean M, (2) the variation in M over time, (3) the relative error in MVPA, and (4) the magnitude of MVPA relative to FL (instantaneous terminal fishing mortality rate) and decreases with increases in magnitude of the true variation of recruitment or the true correlation with the environmental factor (all else being equal). This bias is not large under most conditions, but it is likely to be more important in short-lived, high-M species than the similar but counteracting bias caused by aging errors. Sensitivity analyses can demonstrate how various MVPA values affect conclusions about environmental correlates with recruitment.
Bias in Hydroacoustic Estimates of Fish Abundance due to Acoustic Shadowing: Evidence from Day–Night Surveys of Vertically Migrating Fish
Authors: Appenzeller A. R. , Leggett W. C.
Published: September 2009

We investigated the hypothesis that fish schooling behavior leads to underestimation of fish abundance when assessed by acoustic methods. Current methods for acoustic quantification of fish abundance rely on the assumption that fish biomass and numerical fish abundance are linearly related to acoustic scattering under all natural fish densities. However, cage experiments as well as field observations have indicated that acoustic shadowing effects occur at very dense and large aggregations of fish. Acoustic surveys of the pelagic fish community of Lake Memphremagog, Quebec, were conducted when fish were aggregated and dispersed. These differences in aggregation were related to diel responses to light levels. We found that estimates of fish abundance, as measured by echo integration, were consistently and significantly lower when fish were aggregated in dense schools. This bias was not due to diel changes in average echo level per fish, which exhibited no relationship to diel changes in vertical and hortizontal distributions. We conclude that the reduced abundance estimates obtained when fish were aggregated resulted from acoustic shadowing. Our data suggest that this bias may be as large as 50%.
Alteration of Reproductive Steroids of Male Winter Flounder (Pleuronectes americanus) Chronically Exposed to Low Levels of Crude Oil in Sediments
Authors: Truscott Beryl , Idler David R. , Fletcher Garth L.
Published: September 2009

When male winter flounder (Pleuronectes americanus) were held in seawater for 4 mo exposed to sand treated with five low levels of crude oil, there was a significant reduction in testosterone and 11-ketotesterone glucuronides in blood plasma. At the two higher levels of oil the concentrations of plasma glucuronides were similar but very significantly lower than in the controls or the three lower levels of oil. For both androgens the ratio of glucuronides to free steroids declined in a stepwise fashion. Free testosterone and 11-ketotestosterone plasma levels were not affected significantly by any concentration of oil in sediment. Liver weights as a percentage of body weight were significantly increased at the two highest levels of oil in the sediments, but neither body weights nor testes weights were altered by exposure to oil. It has been suggested that androgen glucuronides can function as pheromones in some fish and this is one potentially deleterious effect of exposure to oil.
MONOTONIC ABSTRACTION: ON EFFICIENT VERIFICATION OF PARAMETERIZED SYSTEMS
Authors: ABDULLA PAROSH AZIZ , DELZANNO GIORGIO , HENDA NOOMENE BEN , REZINE AHMED
Published: September 2009

We introduce the simple and efficient method of monotonic abstraction to prove safety properties for parameterized systems with linear topologies. A process in the system is a finite-state automaton, where the transitions are guarded by both local and global conditions. Processes may communicate via broadcast, rendez-vous and shared variables over finite domains. The method of monotonic abstraction derives an over-approximation of the induced transition system that allows the use of a simple class of regular expressions as a symbolic representation. Compared to traditional regular model checking methods, the analysis does not require the manipulation of transducers, and hence its simplicity and efficiency. We have implemented a prototype that works well on several mutual exclusion algorithms and cache coherence protocols.
THE LENGTH OF SUBSET REACHABILITY IN NONDETERMINISTIC AUTOMATA
Authors: MARTYUGIN PAVEL
Published: September 2009

We study subset reachability in nondeterministic finite automata and look for bounds of the length of the shortest reaching words for automata with a fixed number of states. We obtain such bounds for nondeterministic automata over 2-letter, 3-letter and arbitrary alphabets.a
ON UNIFORMLY RECURRENT MORPHIC SEQUENCES
Authors: NICOLAS FRANCOIS , PRITYKIN YURI
Published: September 2009

A pure morphic sequence is a right-infinite, symbolic sequence obtained by iterating a letter-to-word substitution. For instance, the Fibonacci sequence and the Thue–Morse sequence, which play an important role in theoretical computer science, are pure morphic. Define a coding as a letter-to-letter substitution. The image of a pure morphic sequence under a coding is called a morphic sequence.

A sequence x is called uniformly recurrent if for each finite subword u of x there exists an integer l such that u occurs in every l-length subword of x.

The paper mainly focuses on the problem of deciding whether a given morphic sequence is uniformly recurrent. Although the status of the problem remains open, we show some evidence for its decidability: in particular, we prove that it can be solved in polynomial time on pure morphic sequences and on automatic sequences.

In addition, we prove that the complexity of every uniformly recurrent, morphic sequence has at most linear growth: here, complexity is understood as the function that maps each positive integer n to the number of distinct n-length subwords occurring in the sequence.
QUASICLASSICAL FOURIER PATH INTEGRAL QUANTUM CORRECTION TERMS TO THE KINETIC ENERGY OF INTERACTING QUANTUM MANY-BODY SYSTEMS
Authors: GERNOTH K. A.
Published: September 2009

A quasiclassical expression for the kinetic energy of interacting quantum many-body systems is derived from the full quantum expression for the kinetic energy as derived by means of the Fourier path integral representation of the canonical many-body density matrix of such systems. This quasiclassical form of the kinetic energy may be cast in the shape of thermodynamic expectation values w.r.t. to the classical Boltzmann distribution of the many-body system, which involves only the many-body interaction in contrast to the full Fourier path integral quantum distribution, which carries contributions also from the many-body kinetic energy operator. The quasiclassical quantum correction terms to the classical Boltzmann equipartition value are valid when the product of temperature and particle mass is large and then lead to significant technical simplifications and increase of speed of Monte Carlo computations of the quantum kinetic energy. The formal findings are tested numerically in quantum Fourier path integral versus classical Monte Carlo simulations.
CHAOTIC MODES IN SCALE FREE OPINION NETWORKS
Authors: KUSMARTSEV FEO V. , KÜRTEN KARL E.
Published: September 2009

In this paper, we investigate processes associated with formation of public opinion in varies directed random, scale free and small-world social networks. The important factor of the opinion formation is the existence of contrarians which were discovered by Granovetter in various social psychology experiments1,2,3 long ago and later introduced in sociophysics by Galam.4 When the density of contrarians increases the system behavior drastically changes at some critical value. At high density of contrarians the system can never arrive to a consensus state and periodically oscillates with different periods depending on specific structure of the network. At small density of the contrarians the behavior is manifold. It depends primary on the initial state of the system. If initially the majority of the population agrees with each other a state of stable majority may be easily reached. However when originally the population is divided in nearly equal parts consensus can never be reached. We model the emergence of collective decision making by considering N interacting agents, whose opinions are described by two state Ising spin variable associated with YES and NO. We show that the dynamical behaviors are very sensitive not only to the density of the contrarians but also to the network topology. We find that a phase of social chaos may arise in various dynamical processes of opinion formation in many realistic models. We compare the prediction of the theory with data describing the dynamics of the average opinion of the USA population collected on a day-by-day basis by varies media sources during the last six month before the final Obama-McCain election. The qualitative ouctome is in reasonable agreement with the prediction of our theory. In fact, the analyses of these data made within the paradigm of our theory indicates that even in this campaign there were chaotic elements where the public opinion migrated in an unpredictable chaotic way. The existence of such a phase of social chaos reflects a main feature of the human being associated with some doubts and uncertainty and especially associated with contrarians which undoubtly exist in any society.
DECONFINEMENT AND QUANTUM LIQUID CRYSTALLINE STATES OF DIPOLAR FERMIONS IN OPTICAL LATTICES
Authors: CARR SAM T. , QUINTANILLA JORGE , BETOURAS JOSEPH J.
Published: September 2009

We describe a simple model of fermions in quasi-one dimension that features interaction-induced deconfinement (a phase transition where the effective dimensionality of the system increases as interactions are turned on) and which can be realised using dipolar fermions in an optical lattice1. The model provides a relisation of a "soft quantum matter" phase diagram of strongly-correlated fermions, featuring meta-nematic, smectic and crystalline states, in addition to the normal Fermi liquid. In this paper we review the model and discuss in detail the mechanism behind each of these transitions on the basis of bosonization and detailed analysis of the RPA susceptibility.
FLUID HELIUM-4 IN THERMAL EQUILIBRIUM
Authors: GERNOTH K. A. , RISTIG M. L.
Published: September 2009

The microscopic quantum structure of fluid 4 He may be clearly revealed by a proper decomposition of its spatial correlations into quantum statistical components and direct quantum correlations. This decomposition permits to elucidate the competition between the short-ranged statistical (or particle exchange) correlations and the quantum correlations brought about by the existing strong interparticle repulsion at short relative particle-particle distances. The appropriate method of choice is provided by correlated density-matrix (CDM) theory. It does not only permit a detailed formal analysis of this competition but also allows for a quantitative numerical computation of correlation functions, structure functions, and momentum and energy distributions. The theoretical CDM results for 4 He are, so far as possible, compared with results from path-integral Monte Carlo (PIMC) calculations and with available experimental results. Reported are CDM results on relevant structure functions, correlation functions in coordinate space, kinetic energy distributions, and gross quantitities such as the exchange energy for fluid 4 He . The calculations are performed for normal helium at various temperatures in the range T BE = 2.17 K ≤ T < 14 K .
TOPOLOGICAL ASPECTS OF THE SPECIFIC HEAT
Authors: SARRIS C. M. , PROTO A. N.
Published: September 2009

We describe how the specific heat of a quantum system is related to a positive definite metric defined on the generalized phase space in which the dynamics and thermodynamics of the system take place. This relationship is given through the components of a second-rank covariant metric tensor, enhancing a topological nature of the specific heat. We also present two examples where it can be seen how the uncertainty principle imposes strong constraints on the values achieved by the specific heat showing its inherent quantum nature.
EFFECTS OF ELECTRON-ELECTRON INTERACTIONS IN TWO DIMENSIONS
Authors: KRAVCHENKO S. V.
Published: September 2009

Strong electron-electron interactions in dilute two-dimensional electron systems in silicon lead to Pauli spin susceptibility growing critically at low electron densities. This effect originates from renormalization of the effective mass rather than the g-factor. The relative mass enhancement is system- and disorder-independent, which suggests that it is determined by electron-electron interactions only.
TALKING BREATHER QUBITS
Authors: FUJII TOSHIYUKI , NISHIDA MUNEHIRO , TANDA SATOSHI , HATAKENAKA NORIYUKI
Published: September 2009

Breather is an elementary excitation regarded as a bound state of a fluxon and an antifluxon in a long Josephson junction. In quantum-mechanical regime, the breather energy is quantized so that the breather can be considered as an artificial moving atom. We propose a new type of fluxon qubit that is constructed by quantum-mechanical superposition of the breather's states. We describe quantum logic gates of breather qubit required for constructing quantum computer. In addition, our qubit can move in the system so that transfer of quntum information is possible between mobile qubits as well as stationary qubits. Our talking qubits support the global information sharing in quantum information networks.
FORMULATING JOSEPHSON EFFECTS AND VORTICES BY REFORMULATED MAXWELL EQUATIONS
Authors: XIAO JIANHUA
Published: September 2009

Maxwell equations are not logical consistent. This problem is caused by the implication that the divergence and the curl of a vector are not related. Based on Chen's S - R decomposition of a rank-two tensor, this logical un-consistency is discarded and, as a consequence, the classical Maxwell equations are reformulated to deduce London equations. From boundary field point, the relations between Josephson current and outside magnetic field are established, which shows that the Josephson current is produced by vortices of boundary magnetic field. From local field point, the first London equation corresponds to the local average rotation of electric field and the second London equation corresponds to the local average rotation of magnetic field. The relation between the Josephson effects and vortices of electromagnetic fields is discussed.
FREE AND INDUCED VORTICES MOTION IN THE JOSEPHSON JUNCTION COUPLED WITH WAVEGUIDE
Authors: MALISHEVSKII A. S. , SILIN V. P. , URYUPIN S. A. , USPENSKII S. G.
Published: September 2009

A model for the analytic description of vortices in a system consisting of a long Josephson junction and a waveguide is formulated. For this system all types of elementary vortices and its chains are listed. The allowed range of velocities of an elementary vortex is found. It is established that a free vortex can be a fast one which moves with velocity much greater than the Swihart velocity of Josephson junction. The effect of the waveguide on the induced vortices motion is studied. It is shown that fast vortex can be generated by relatively small values of bias current density. The effect of vortex Cherenkov losses on the bias current is described.
NONDEGENERATE PARAMETRIC AMPLIFICATION IN SUPERLATTICES AND THE LIMITS OF STRONG AND WEAK DISSIPATION
Authors: HYART TIMO , ALEKSEEV KIRILL N.
Published: September 2009

We develop a semiclassical theory of the nondegenerate parametric amplification in a single miniband of superlattice. We present the formulas describing absorption and gain of signal and idler fields in superlattice and analyze the limiting cases of strong and weak dissipation. We show how the well-known Manley-Rowe relations arise in the tight-binding lattice in the weak dissipation limit. Our results can be applied to an amplification of THz signals in semiconductor superlattices and a control of nonlinear transport of cold atoms in optical lattices.
MAGNETIC RELAXATION OF SUPERCONDUCTING QUANTUM DOT AND TUNNELING OF ELECTRON IN A MAGNETIC FIELD
Authors: GULEVICH D. R. , KUSMARTSEV F. V.
Published: September 2009

Quantum tunneling of vortices had been found to be an important novel phenomena for description of low temperature creep in high temperature superconductors (HTSCs). We speculate that quantum tunneling may be also exhibited in mesoscopic superconductors due to vortices trapped by the Bean-Livingston barrier. The London approximation and method of images is used to estimate the shape of the potential well in superconducting HTSC quantum dot. To calculate the escape rate we use the instanton technique. We model the vortex by a quantum particle tunneling from a two-dimensional ground state under magnetic field applied in the transverse direction. The resulting decay rates obtained by the instanton approach and conventional WKB are compared revealing complete coincidence with each other.
THEORETICAL BACKGROUNDS OF NONLINEAR THz SPECTROSCOPY OF SEMICONDUCTOR SUPERLATTICES
Authors: SHOROKHOV ALEXEY V. , ALEKSEEV KIRILL N.
Published: September 2009

We consider terahertz absorption and gain in a single miniband of semiconductor superlattice subject to a bichromatic electric field in the most general case of commensurate frequencies of the probe and pump fields. Using an exact solution of Boltzmann transport equation, we show that in the small-signal limit the formulas for absorption always contain two distinct terms related to the parametric and incoherent interactions of miniband electrons with the alternating pump field. It provides a theoretical background for a control of THz gain without switching to the negative differential conductivity state. For pedagogical reasons we present derivations of formulas in detail.
SOME PECULIARITIES OF USING OF DIELECTRIC RESONATORS IN MICROWAVE SURFACE IMPEDANCE MEASUREMENTS
Authors: NURGALIEV T.
Published: September 2009

A simple equivalent circuit of the dielectric resonator technique, using for measurement of the surface resistance of the samples of non-standard dimensions, was considered and analyzed. It was shown that the coefficient (the geometry factor) relating the surface resistance of the sample to the quality factor may be different in the cases when the inductive resistance (caused by the external inductance) of the sample exceeds significantly its active resistance and when these resistances are of the same order. It was shown too, that an anomaly in the RS versus T dependence (i.e., a decreasing of the surface resistance with increase of the temperature) is possible in double layer structures with thin superconductor and metal films.
ELECTROSTATIC FIELD IN SUPERCONDUCTORS III: THERMODYNAMIC APPROACH
Authors: KOLÁČEK JAN , LIPAVSKÝ PAVEL
Published: September 2009

In the diamagnetic Meissner state, the superconductor is in the equilibrium. The non-zero electrostatic field thus represents a minimum of the free energy. The thermodynamical formulation of the scalar potential allows us to include forces corresponding to the free energy of condensation – the so called pairing forces.
A GENERATING FUNCTION APPROACH TO THE SURFACE AREAS OF SOME INTERCONNECTION NETWORKS
Authors: CHENG EDDIE , QIU KE , SHEN ZHIZHANG
Published: September 2009

An important and interesting parameter of an interconnection network is the number of vertices of a specific distance from a specific vertex. This is known as the surface area or the Whitney number of the second kind. In this paper, we give explicit formulas for the surface areas of the (n, k)-star graphs and the arrangement graphs via the generating function technique. As a direct consequence, these formulas will also provide such explicit formulas for the star graphs, the alternating group graphs and the split-stars since these graphs are related to the (n, k)-star graphs and the arrangement graphs. In addition, we derive the average distances for these graphs.
FAULT-TOLERANT HAMILTONIAN LACEABILITY AND FAULT-TOLERANT CONDITIONAL HAMILTONIAN FOR BIPARTITE HYPERCUBE-LIKE NETWORKS
Authors: LIN CHENG-KUAN , HO TUNG-YANG , TAN JIMMY J. M. , HSU LIH-HSING
Published: September 2009

A bipartite graph G is hamiltonian laceable if there is a hamiltonian path between any two vertices of G from distinct vertex bipartite sets. A bipartite graph G is k-edge fault-tolerant hamiltonian laceable if G - F is hamiltonian laceable for every F ⊆ E(G) with |F| ≤ k. A graph G is k-edge fault-tolerant conditional hamiltonian if G - F is hamiltonian for every F ⊆ E(G) with |F| ≤ k and δ(G - F) ≥ 2. Let G0 = (V0, E0) and G1 = (V1, E1) be two disjoint graphs with |V0| = |V1|. Let Er = {(v,ɸ(v)) | v ϵ V0,ɸ(v) ϵ V1, and ɸ: V0 → V1 is a bijection}. Let G = G0 ⊕ G1 = (V0 ⋃ V1, E0 ⋃ E1 ⋃ Er). The set of n-dimensional hypercube-like graphHn is defined recursively as (a) H1 = K2, K2 is the complete graph with two vertices, and (b) if G0 and G1 are in Hn, then G = G0 ⊕ G1 is in Hn+1. Let Bn be the set of graphs G where G is bipartite and G ϵ Hn. In this paper, we show that every graph in Bn is (n - 2)-edge fault-tolerant hamiltonian laceable if n ≥ 2 and every graph in Bn is (2n - 5)-edge fault-tolerant conditional hamiltonian if n ≥ 3.
Modulation of Mixed Conductivity in Nanocrystalline Electrolytes by Heterogeneous Doping
Authors: Litzelman Scott , Tuller Harry L.
Published: September 2009

Over the past decade, the most commonly studied nanocrystalline electroceramic system has been cerium oxide. Ionic conduction is traditionally introduced into this system via homogeneous doping, though the maximum conductivity is limited by carrier mobility at high doping levels. In this work, heterogeneous doping is explored as a potential means for enhanced ionic conductivity. Nanocrystalline CeO2 thin films were deposited by pulsed laser deposition and modified by in-diffusion of Ni and Gd along columnar grain boundaries. To separate the ionic and electronic contributions to the conductivity, electron-blocking microelectrodes, consisting of dense yttria-stabilized zirconia and porous Pt layers, were fabricated on the microscale. After in-diffusion, both the ionic and electronic partial conductivities decreased relative to the as-deposited state. This result is analyzed in terms of the grain boundary chemistry and space charge potential, as well as segregation of acceptor impurities within the ceria thin films.
In Situ Synchrotron X-ray Spectroscopy of Lanthanum Manganite Solid Oxide Fuel Cell Electrodes
Authors: Chang Kee-Chul , Yildiz Bilge , Myers Deborah J. , Carter John D. , You Hoydoo
Published: September 2009

We investigated the underlying physical and chemical causes of the improvement of electrochemical activity of the cathode in solid oxide fuel cells (SOFC) under long term cathodic or anodic polarization, termed 'current conditioning', through in situ X-ray absorption spectroscopy (XAS). The electrodes were powder La0.8Sr0.2MnO3 (LSM) made with spray pyrolysis and thin films of LSM and La0.8Ca0.2MnO3 (LCM) grown by pulsed laser deposition (PLD), all on single crystal Yttria stablized Zirconia (YSZ) substrates. Changes in the XAS of the Mn K, La L3 as well as the Sr K edge for LSM during current conditioning were studied. Our results shows no significant oxidation state changes for the Mn, but instead suggests that the redistribution of cation concentration profiles inside the pervoskite electrode may be the important factor in current conditioning.
Nonlinear Analysis of the Oxygen Surface Reaction and Thermodynamic Behavior of La1-xSrxCoO3-δ
Authors: DeMartini Andrew T. , Unemoto Atsushi , Kawada Tatsuya , Adler Stuart
Published: September 2009

Oxygen exchange on thin films of La1-xSrxCoO3-δ (LSC) was studied at high temperature using linear and nonlinear electrochemical impedance spectroscopy (EIS and NLEIS). Both the chemical capacitance and nonlinear kinetics suggest that the thermodynamic characteristics of the films are shifted from that of freestanding bulk LSC of the same cation composition. For La0.6Sr0.4CoO3-δ (LSC-64), the film thermodynamics appears to vary with fabrication technique and conditions. For La0.8Sr0.2CoO3-δ (LSC-82), our preliminary results suggest that thermodynamics governing the surface and bulk differ, possibly due to segregation of cations at the electrode surface. All results appear to be explainable under the assumption that oxygen reduction at the surface is limited by dissociative adsorption.
Investigation of Phase & Strain Distributions Inside of Solid Oxide Fuel Cells
Authors: Liu Di-Jia , Almer Jon
Published: September 2009

A microfocused, high energy wide angle X-ray diffraction method with micron-level spatial resolution was developed to investigate phase and strain distributions of individual components inside of planar solid oxide fuel cells (SOFCs). Examples were given for the study of a commercial SOFC sample deactivated after direct contact with the high temperature stainless steel current collector under typical operating conditions.
High Performance Ceria/Bismuth Oxide Bilayered Electrolyte IT-SOFC
Authors: Ahn Jin Soo , Camaratta Matthew , Lee Kang Taek , Yoon Hee Sung , Lee Byung Wook , Wachsman E. D.
Published: September 2009

This study examines the incremental improvement in SOFC performance comprised of components prepared from a wide range of techniques-from pressed anodes to tape-cast anodes, from GDC single-layer electrolytes to ESB/GDC bilayer, and from LSCF-GDC composite cathodes to optimized BRO7-ESB composites. GDC single-layer electrolyte based SOFCs were prepared from two different fabrications and exhibit maximum power densities ranging from 338 to 407 mW/cm2, at 650 {degree sign}C. At each fabrication stage, an ESB layer was applied to form a bilayer electrolyte. ESB was deposited by screen printing and drop coating. The result confirms that depending on a fabrication route the bilayer electrolyte can reduce the total ASR 33~48 % and increase the maximum power density 51~74 %. Using a combination of the materials and fabrication routes, a maximum power density of 808 mW/cm2 and 0.133 total cell ASR was achieved at 650 {degree sign}C for a bilayer cell.
Improvement of Micro Tubular SOFCs using Multi-Layered Electrolyte
Authors: Suzuki Toshio , Funahashi Yoshihiro , Yamaguchi Toshiaki , Fujishuro Yoshinobu , Awano Masanobu
Published: September 2009

Fabrication technology of multi-layered electrolyte for micro tubular SOFCs has been developed. Sc2O3 stabilized ZrO2(ScSZ) and Gd2O3-doped CeO2 (GDC) was selected for the electrolyte materials and a GDC-ScSZ-GDC multi-layered electrolyte was successfully prepared using multiple dip coating and co-firing technique. The thickness of each layer for the electrolyte was about 3, 3, and 12 micron, respectively. The cell performance test showed the open circuit voltage (OCV) of over 1 V at 600oC or higher, while a SOFC with 10 micron thick GDC electrolyte showed the OCV of 0.78 V at 600oC. The cell performance of 0.35 Wcm-2 @ 0.7 V was obtained at the operating temperature of 650 oC.
Fabrication and Characterization of Ni-Doped Ceria Anode-Supported Cells Using Lanthanum Gallate-Based Electrolyte
Authors: Yoshida Hiroyuki , Inagaki Toru , Hashino Koji , Kawano Mitsunobu , Nagahara Hideyuki , Ijichi Hiroshi
Published: September 2009

Two improvements were made on the fabrication process of anode-supported cells using lanthanum gallate-based electrolyte (LSGM). One is a sintering process, anode-substrate and interlayer were co-sintered first, and then the electrolyte was screen-printed and sintered. Another one is that double-doped ceria with La and Sm was used as the interlayer. The diffusion of Ni into LSGM was avoided even after sintering of the electrolyte at 1400ºC by applying their improvements. The cell was fabricated by co-sintering of NiO-Ce0.8Sm0.2O1.9 anode-substrate and Ce0.57Sm0.14La0.19O2-δ interlayer at 1500ºC followed by the sintering of LSGM at 1400ºC, the open circuit voltage and the maximum power density of the cell were 0.768 V and 0.20 W/cm2, respectively.
Carbon Deposition and Electrochemical Reaction of Anode for SOFC in Methane Containing Atmosphere
Authors: Yashiro Keiji , Takase Mitsunari , Sato Kazuhisa , Kawada Tatsuya , Mizusaki Junichiro
Published: September 2009

To investigate carbon deposition on Ni anode for solid oxide fuel cells, in situ microscopic observation was performed, Carbon deposition and oxidation was successfully observed by in situ Raman microscopy combined with electrochemical setup. It is generally believed that carbon deposition is determined by steam / carbon ratio. But in reality, in the case of methane-steam system, even when steam / carbon ratio exceeds carbon deposition limit, carbon is not deposited, unless methane is completely equilibrated with steam. Not only S/C but gas equilibration process should be taken into account to control the carbon deposition.
Distribution of Carbon Deposition and Proton Conductor in Nickel/Yittria-Stablized Zirconia Anode Infiltrated by Proton Conductor of SrZr0.95Y0.05O3-α after Power Generation in Dry Methane Fuel
Authors: Jin Yongcheng , Yasutake Hiroyuki , Yamahara Keij , Ihara Manabu
Published: September 2009

Distribution of carbon deposition on the cross-section of an Ni/YSZ anode after an accelerated degradation test in dry methane was analyzed using SEM-EDS. The area near the anode-surface side was favored for carbon deposition than that near the electrolyte side, suggesting that the electrochemically produced H2O and oxygen coverage around the TPB near the anode-surface side were insufficient for carbon removal reaction. To enhance the reaction of these two species, a proton-conductor of SrZr0.95Y0.05O3-α(SZY) was used to modify the Ni/YSZ anode structure by the infiltration method. The Ni/YSZ infiltrated with SZY anode(Ni/YSZ-SZY) showed a unique structure in which the distribution of SZY was mainly localized near the anode-surface side. In conclusion, structural modification of the Ni/YSZ anode by the addition of the proton-conductor SZY improved the operational stability of the anode in dry methane.
Experimental Characterization of Thin-film Ceria Solid Oxide Fuel Cell Anodes
Authors: DeCaluwe Steven C. , Sukeshini A. Mary , Jackson Gregory S.
Published: September 2009

This study presents an experimental effort to elucidate the role of CeO2-x in composite SOFC anodes, by characterizing electrochemical oxidation of small fuel molecules (H2, CO) on thin-film ceria anodes. Thin ceria films were sputter-deposited onto thick YSZ-electrolyte-supported button cells with high-surface-area, porous LSM/YSZ cathodes. The mixed ionic-electronic conductivity of ceria provides multiple reaction pathways for electrochemical oxidation and electrochemical characterization of the ceria films over a range of gas compositions at temperatures from 650 to 850 {degree sign}C provide a basis for elucidating the importance of competing mechanisms for fuel oxidation on the ceria. Analysis of the experiment results provides a basis for formulating a micro-kinetic mechanism for the oxidation of small fuel species on ceria anodes which can be the implemented in SOFC modeling efforts for optimizing ceria-based composite anodes.
Electrical Conductivity and Thermoelectric Power of La2-xSrxNiO4+δ
Authors: Nakamura Takashi , Yashiro Keiji , Sato Kazuhisa , Mizusaki Junichiro
Published: September 2009

Electrical conductivity, Seebeck coefficient, and nonstoichiometric oxygen content of La2-xSrxNiO4+δ (x = 0, 0.2, 0.4) were measured as a function of Sr content, temperature, and oxygen partial pressure. At above around 873 K, mobility of hole decrease as temperature increase. The temperature dependence of hole mobility indicate large polaron conduction. The relationship between Seebeck coefficient and electrical conductivity is explained by metal like band conduction model. The behavior of electrical conductivity and Seebeck coefficient strongly suggests that electron (hole) is itinerant in La2-xSrxNiO4+δ at high temperatures.
Composite Ceramic Membranes for Oxygen Separation in Carbon Capture and Storage Systems
Authors: Druce John W. , Kilner John
Published: September 2009

CGO-LSCF composite membranes have been characterised with a view to applications in oxygen separators for oxyfueled boilers in Carbon Capture and Storage (CCS) systems. Although commonly believed to be chemically stable together, evidence is presented that an interdiffusion reaction occurs on sintering at 1250ºC for 4 hours. Isotopic oxygen exchange measurements show that this does not appear to have any detrimental effect on the oxygen exchange properties. Similarly, electrical conductivity was also measured, and no detrimental effect was observed for these properties.
Performance of Thermally Modified, Potentiometric Gas Sensor Array in Gas Mixtures
Authors: Blackburn Bryan M. , Wachsman E. D.
Published: September 2009

Gas sensors are needed to monitor emissions in combustion exhausts and industrial processes due to health, environmental, and economic concerns. In order to achieve improved device performance, we have shown that a single device with multiple sensing electrodes locally heated to different temperatures can significantly improve selectivity and sensitivity. A first- and second-generation gas sensor array have been demonstrated for both indirect and direct detection of individual NO and NO2 concentrations. In this study, the effects of ambient temperature, gas flow rates, and local electrode temperature on the sensor signal are examined. The gas sensor array was also tested using various gas mixtures of O2, NO, NO2, CO, and CO2. Temperature programmed reaction (TPR), temperature programmed desorption (TPD), XPS, and DRIFTS results from other experiments will be reviewed to explain some of the results.
Advances in Rapid Prototyping for Solid State Ionics
Authors: Blackburn Bryan M. , Camaratta Matthew , Wachsman E. D.
Published: September 2009

Scientists and engineers often need to consider several material or design properties with regard to solid-state ionics. However, most techniques for fabricating devices or scientific samples have several drawbacks. These include, but are not limited to, material incompatibility, lack of fine-line resolution, or expensive/time consuming when considering iterative design processes. This work involves the development of materials for use with a new type of rapid-prototype platform (nScrypt, Inc). The ultimate goal is to produce multiple design schemes for various devices (e.g., fuel cells and gas sensors) which will allow for quick analysis and engineering turnaround for improved performance.
Triazole-based Electrolytes for Fuel Cell Applications: Material Properties and Proton Transfer Capabilities
Authors: Maalouf Manale , Ghassemi Hossein , Lee Choong-Gon , Zawodzinski Thomas
Published: September 2009

4,5-Dicyano-1H-[1,2,3]-Triazole (DCTz) exhibits a very low proton affinity. This makes it a possible water replacement for proton transport in high temperature polymer electrolyte membranes. A detailed investigation is carried out to define various physical properties as well as the proton transfer characteristics of DCTz. Thermogravimetric analysis showed that DCTz as well as DCTz salts are thermally stable at high temperature (> 100{degree sign}C). 1H NMR spectra reveal proton exchange in DCTz solutions. The NMR spectroscopy reveals the dependence of proton transport on concentration, temperature and the presence of excess protons added as acid dopants.
Rare Earth Phosphate Glass and Glass-Ceramic Proton Conductors
Authors: Ray Hannah L. , De Jonghe Lutgard , Wang Ruigang
Published: September 2009

The structure and conductivity of cerium and lanthanum phosphate glasses and glass-ceramics were investigated. The effects of varying the metal to phosphate ratio in the glasses, doping LaP3O9 glasses with Ce, and recrystallization of CeP3O9 glasses, on the glasses' microstructure and total conductivity were investigated using XRD, SEM, and AC impedance techniques. Strong increases in conductivity occurred when the glasses were recrystallized: the conductivity of a cerium metaphosphate glass increased conductivity after recrystallization from 10-7.5 S/cm to 10-6 S/cm at 400{degree sign}C.
Synthesis and Proton Transport Property of Poly(aspartic acid) Thin Film on MgO(100) Substrate
Authors: Nagao Yuki , Ando Mariko , Maekawa Hideki , Chang Chih Hao , Iguchi Fumitada , Sata Noriko
Published: September 2009

An enhancement in proton conductivity for poly(aspartic acid)/sodium polyaspartate (P-Asp) by synthesizing thin film on MgO substrate was investigated. The average degrees of polymerization and molecular weight were ~70 and ~9400, respectively. The degree of protonation in the carboxylic acid groups was 10 %. The proton conductivities of the pelletized P-Asp and thin film were 6.4 x 10-4 and 3.4 x 10-3 S cm-1, respectively, under a relative humidity of 70 % and 298 K. The proton conductivity of the thin film was found to be five times higher than that of the pelletized P-Asp. The activation energy for the proton conduction of the pelletized P-Asp was 0.89 eV. The activation energy of P-Asp thin film was smaller than that of the pelletized sample. Application of this phenomenon may lead to a new method for producing highly proton-conductive material.
New Developments in Conducting Polymers Based on Commercial Gelatin
Authors: Silva Manuela , Barbosa Paula , Rodrigues Luísa
Published: September 2009

Nowadays electrochromic materials have been attracting much interest in controllable light-reflective or light-transmissive devices for optical information and storage. These devices have potential use in various applications such automotive industry (rear-view mirrors and visors) and architecture ("smart-windows" for vehicles and buildings) [1]. In this work a new kind of conducting materials produced by solvent-casting technique with commercial gelatin, doped with lithium perchlorate (LiClO4) are reported. Recent attention has been focused on the use of natural polymers due to their biodegrability, low production cost and good physical and chemical properties. The characterization of the electrolytes prepared will be made with data obtained by thermal analysis and studies of ionic conductivity. Electrolyte samples were obtained as transparent, amorphous films and at room temperature the highest conductivity was observed with the gelatin 5% LiClO4 EC + PC composition (2.04x10-9 ohm-1cm-1).
Electrochemical Properties of Composite Solid Electrolytes LiClO4 - MgO
Authors: Ulihin Artem S. , Uvarov Nikolai F.
Published: September 2009

Composite solid electrolytes (CSE) in the system LiClO4-MgO with highly-dispersed magnesium oxide (with the specific surface area of 220 m2/g) were synthesized and their electrical properties were investigated. The concentration dependence of conductivity has a maximum of 10-2 S/cm at 200оС at 80-90 m/o (40-50 v/o) MgO. Similar behavior is typical for CSE where the conductivity occurs via ionic salt / oxide interface regions. Comparison of ac-conductivities and volt-ampere dependences measured in dry and humid atmospheres suggests that the conductivity is governed by lithium cations.
The Barrier Formation Mechanism on SrTiO3 for High-Temperature Photo-Electronic Devices
Authors: Horikiri Fumimasa , Ichikawa Tomoyuki , Sato Kazuhisa , Yashiro Keiji , Kawada Tatsuya , Mizusaki Junichiro
Published: September 2009

Investigation was made on the interface characteristics between various metal electrodes and SrTiO3 single crystals at high-temperatures. The interfaces showed the non-linear current-voltage characteristics, which was caused by the Schottky barrier formed at the interface. The estimated Schottky barrier heights were approximately 1.5 eV, which were almost independent of the work function of electrode metal. These results indicated that the barrier formation obeys the diffusion mechanism for the Bardeen limit at high-temperature.
Tissue-specific PAI-1 gene expression and glycosylation pattern in insulin-resistant old rats
Authors: Serrano R. , Barrenetxe J. , Orbe J. , Rodríguez J. A. , Gallardo N. , Martínez C. , Andrés A. , Páramo J. A.
Published: September 2009

Increased levels of plasminogen activator inhibitor-1 (PAI-1) have been associated with obesity, aging, insulin resistance, and type 2 diabetes, conditions that contribute to increased cardiovascular risk. PAI-1 is expressed in a variety of tissues, but the cellular origin of plasma PAI-1 is unknown. To link insulin resistance, aging, and cardiovascular disease, we examined the expression and glycosylation pattern of PAI-1 in liver and white adipose tissue (WAT) from adult (3 mo) and insulin-resistant old (24 mo) Wistar rats. Glycosylated PAI-1 protein was also purified by affinity chromatography from endothelial culture supernatans to analyze its inhibitory activity. We also analyzed the contribution of adipocytes and stromal vascular cells from WAT to PAI-1 levels with aging. Aging caused a significant increase of PAI-1 mRNA ( P < 0.001) in WAT that was predominantly due to the adipocytes and not to stroma-vascular cells, while there was no modification in liver from aged rats. Moreover, PAI-1 expression increased during preadipocyte differentiation ( P < 0.001). Furthermore, we found a tissue-dependent PAI-1 glycosylation pattern: adipose tissue only expresses the glycosylated PAI-1 form, whereas the liver mainly expresses the nonglycosylated form. Finally, we also found evidences suggesting that the glycosylated PAI-1 form shows higher inhibitory activity than the nonglycosylated. Our data suggest that WAT may be a major source of the elevated plasma levels of PAI-1 in insulin-resistant old rats. Additionally, the high degree of PAI-1 glycosylation and activity, together with the significant increase in visceral fat in old rats, may well contribute to an increased cardiovascular risk associated with insulin-resistant states.
Preclinical Profile of a Potent γ-Secretase Inhibitor Targeting Notch Signaling with In vivo Efficacy and Pharmacodynamic Properties
Authors: Luistro Leopoldo , He Wei , Smith Melissa , Packman Kathryn , Vilenchik Maria , Carvajal Daisy , Roberts John , Cai James , Berkofsky-Fessler Windy , Hilton Holly , Linn Michael , Flohr Alexander , Jakob-Røtne Roland , Jacobsen Helmut , Glenn Kelli , Heimbrook David , Boylan John F.
Published: September 2009

Notch signaling is an area of great interest in oncology. RO4929097 is a potent and selective inhibitor of γ-secretase, producing inhibitory activity of Notch signaling in tumor cells. The RO4929097 IC50 in cell-free and cellular assays is in the low nanomolar range with >100-fold selectivity with respect to 75 other proteins of various types (receptors, ion channels, and enzymes). RO4929097 inhibits Notch processing in tumor cells as measured by the reduction of intracellular Notch expression by Western blot. This leads to reduced expression of the Notch transcriptional target gene Hes1. RO4929097 does not block tumor cell proliferation or induce apoptosis but instead produces a less transformed, flattened, slower-growing phenotype. RO4929097 is active following oral dosing. Antitumor activity was shown in 7 of 8 xenografts tested on an intermittent or daily schedule in the absence of body weight loss or Notch-related toxicities. Importantly, efficacy is maintained after dosing is terminated. Angiogenesis reverse transcription-PCR array data show reduced expression of several key angiogenic genes. In addition, comparative microarray analysis suggests tumor cell differentiation as an additional mode of action. These preclinical results support evaluation of RO4929097 in clinical studies using an intermittent dosing schedule. A multicenter phase I dose escalation study in oncology is under way. [Cancer Res 2009;69(19):7672–80]
Aberrant Methylation ofAPC, MGMT, RASSF2A, andWif-1Genes in Plasma as a Biomarker for Early Detection of Colorectal Cancer
Authors: Lee Bo Bin , Lee Eun Ju , Jung Eun Hyun , Chun Ho-Kyung , Chang Dong Kyoung , Song Sang Yong , Park Joobae , Kim Duk-Hwan
Published: September 2009

Purpose: To identify epigenetic molecular makers in plasma for the early detection of colorectal cancer.

Experimental Design: We retrospectively analyzed the methylation status of 10 genes in fresh-frozen tissues and corresponding plasma samples from 243 patients with stage I and II sporadic colorectal cancer, 276 healthy individuals, and plasma from 64 colorectal adenoma patients using methylation-specific PCR. The methylation score (Mscore) was used to find molecular markers with high sensitivity and specificity.

Results: Of the 243 colorectal cancer tissues, methylation was detected in 18% for p14, 34% for p16, 27% for APC, 34% for DAPK, 32% for HLTF, 21% for hMLH1, 39% for MGMT, 24% for RARβ2, 58% for RASSF2A, and 74% for Wif-1. Receiver operator characteristic curve analysis in plasma from 243 patients with cancer and 276 healthy individuals showed that the M score of any single gene had a sensitivity of <40% after controlling for age, sex, and tumor location. The specificity of the M score was not different between multigene and single gene analyses, but the sensitivity of the M score was significantly increased by multigene analysis. For all patients, the M score in a model including APC, MGMT, RASSF2A, and Wif-1 genes had a sensitivity of 86.5% and a specificity of 92.1% when 1.6 was used as a cutoff. In this model, the M score had a positive predictive value of 90.6% and a negative predictive value of 88.8%.

Conclusion: The present study suggests that tumor-specific methylation of APC, MGMT, RASSF2A, and Wif-1 genes might be a valuable biomarker in plasma for the early detection of colorectal cancer. (Clin Cancer Res 2009;15(19):6185–91)