bluuebunny/crossref_metadata_2025 huggingface dataset:
Modeling Based on Markov Chains for the Evolution of Pitting Corrosion in Buried Pipelines Carrying Gas
Authors: Bolaños Rodríguez Ernesto , González Islas Juan Carlos , Vega Cano Gaby Yolanda , Flores García Ernesto
Published: October 2011

A stochastic model based on Markov Chains is presented for predicting the time evolution of the pit depth distributions, as manifestation of the corrosion experienced by pipelines carrying gas. The results obtained allow estimating the lifetime of pipelines in service, thereby achieving optimize time and maintenance costs.
Sol-Gel Routes to Replace Chromate Based Treatments for Protection Against Zinc Corrosion
Authors: Meiffren Vincent , Lenormand Pascal , Ansart Florence , Manov Stephan
Published: October 2011

Regarding the environmental consciousness and requirements relative to industrial processes, researchers and end users have to move to more green surface treatments. That is why, the use of toxic compounds such as chromates must be strictly prohibited. So, in order to replace this element preserving an efficient protection against corrosion of metals, a new route using sol-gel process clearly appears as a promising alternative method. In this paper, we investigated three different sol-gel systems in various media (alcohol and/or water) and compared their efficiency in terms of protection against corrosion and environmentally friendliness. Thus, industrial normalized corrosion test and electrochemical analyses such as polarisation curves and EIS measurements were carried out in order to both evaluate and discuss coatings behaviour in corrosive environment.
Metal-Oxides Hole Injection/Extraction Layer in Organic Semiconductor Devices
Authors: Gao Irfan , Gao Yongli
Published: October 2011

We have investigated the counter intuitive phenomenon of inserting a metal oxide layer to improve hole injection or extraction in organic semiconductor devices using ultraviolet photoemission, x-ray photoemission, and inverse photoemission spectroscopy (UPS, XPS and IPES). We observed that metal oxides such as MoOx substantially increase the workfunction. The increase lifts up the highest occupied molecular orbital (HOMO) of the hole transport layer, therefore reduces the energy barrier between the HOMO and the Fermi level. The uplift creates an interface band bending region that results in a steering electric field that encourages the collection of holes at the anode. We have also investigated the effects of ambient and O2 exposure of MoOx. We observe that while most of the electronic energy levels of the oxide remain largely intact, the workfunction reduction is substantial. The effect of annealing MoOx thin films in air will also be discussed.
Catalytic CO Oxidation over Pt Nanoparticles Prepared from the Polyol Reduction Method Supported on Yttria-Stabilized Zirconia
Authors: Isaifan Rima , Dole Holly , Obeid Emil , Lizarraga Leonardo , Baranova Elena A. , Vernoux Philippe
Published: October 2011

Pt nanoparticles were synthesized using a polyol process with ethylene glycol as a reducing agent. Nanoparticles of three average sizes were synthesized (3.8, 2.8 and 1.7 nm) and were deposited on Yttria-Stabilized Zirconia (YSZ), carbon black and γ-Al2O3 resulting in 1 wt. % of Pt on each support. In addition, the conventional wet impregnation method was used to disperse Pt on YSZ. Pt nanoparticles were characterized using transmission electron microscopy and X-ray diffraction. The catalytic activity of all these catalysts was investigated for carbon monoxide oxidationin the temperature range of 25-250 °C. It has been found that Pt/YSZ catalysts prepared by the polyol process presented the highest catalytic performances is spite of the low specific surface area compared to carbon and γ-Al2O3 supports. These performances can be explained based on metal/support interactions effect generated between Pt and YSZ or self-induced electrochemical promotion.
Voltammetric Peak Enhancement of Cefpirome in Cetyltrimethylammonium Bromide
Authors: Jain Rajeev , Lal Vikas , Radhapyari Keisham
Published: October 2011

The objective of the present work is to develop a voltammetric method for the determination of cefpirome in bulk and pharmaceutical formulations and it also deals with the beneficial use of surfactants in the catalysis of electrode reactions. The voltammetric behaviour of cefpirome in Britton Robinson buffer solutions over the pH range 2.0-12.0 using differential pulse voltammetry and cyclic voltammetry has been studied in surfactant media. In the entire pH range a well defined cathodic and anodic peak were observed in cyclic voltammetry. Number of electron transferred in the reduction process was calculated and the reduction mechanism has been postulated on the basis of controlled potential electrolysis and coulometry. The proposed differential pulse voltammetric method allows quantitation over the range 1.0 mgmL-1 and 62 mgmL-1 with detection limit of 1.2 mgmL-1 respectively. The analysis of cefpirome in pharmaceutical formulation exhibited the mean recoveries of 99.7% for the reduction peak.
Investigation of Carbon Supported Pt and PtCo Electrocatalysts by Low-Energy Ion Scattering and X-ray Photoelectron Spectroscopy: Influence of the Surface Characteristics on Performance and Degradation
Authors: Stassi Alessandro , Gatto Irene , Monforte Giuseppe , Passalacqua Enza , Antonucci Vincenzo , Aricò Antonino Salvatore
Published: October 2011

An investigation of the behaviour of carbon-supported Pt and PtCo cathode electro-catalysts was carried out to evaluate their performance and resistance to degradation. Nanosized Pt and PtCo catalysts with similar crystallite size (2.7-2.9 nm) were prepared by using a colloidal route. The surface properties were investigated by X-ray photoelectron spectroscopy (XPS) and low-energy ion scattering spectroscopy (LE-ISS). The formation of a Pt skin layer on the surface of the alloy electro-catalyst was obtained by using a pre-leaching procedure. As result, a significant surface Pt enrichment was observed for the leached Pt-Co electrocatalyst. This characteristic appeared to influence catalysts' performance and degradation. Accelerated tests (electrochemical cycling) at 130 °C in a pressurised PEMFC showed a better stability for the PtCo alloy as compared to Pt. Furthermore, better performance was obtained at high temperatures for the pre-leached PtCo/C as compared to the Pt/C cathode catalyst.
In Situ 3D Imaging and Characterization of Nano-Structures with X-ray Nano-CT Technique
Authors: Wang Yuxin , Chen Yu-chen Karen , Chiu Wilson K.
Published: October 2011

High-resolution x-ray microscopy and nano-CT provides a new approach to non-invasively and non-destructively study nano-structures in situ and in operando. Combined with tunable synchrotron x-ray sources, the elemental and certain chemical compositions can also be mapped dynamically in 3D. These capabilities are valuable for studying electrochemical systems, particularly those involving electrochemical reactions with porous structures at tens of nm to micron scale. The paper gives an introduction of this technique with several examples.
Quantitative Online Detection of Volatile and Non-Volatile Methanol Electrooxidation Products by Combined Electron Impact Mass Spectrometry and Electrospray Ionization Mass Spectrometry
Authors: Zhao Wei , Jusys Zenonas , Behm Rolf Juergen
Published: October 2011

Combination of electron impact ionization (EI-MS) and electrospray ionization mass spectrometry (ESI-MS) allowed us for simultaneous quantitative online detection of both volatile (carbon dioxide) and non-volatile (formic acid and formaldehyde) reaction products during continuous methanol electrooxidation. The overall reaction rate was monitored via the Faradaic current, carbon dioxide formation was followed mass spectrometrically (electron impact mass spectrometry) via a membrane inlet system in a thin-layer flow-cell, while formaldehyde and formic acid were detected by ESI-MS after the online derivatization-extraction-separation procedure described previously (W. Zhao et al., Anal. Chem. 82, 2472 (2010)).
Synthesis and Preparation of Composite Membranes for Direct Methanol Fuel Cells from Poly(Ether Ketone Quinolines)-Poly(Ether Ether Ketone) Blend and Nafion with Non- and Surface Coated Silicotungstic Acid
Authors: Sutrisno Joko , Pramudya Irawan , Fuchs Alan
Published: October 2011

Poly(ether ketone quinoline) has been synthesized as a composite membrane matrix and has a molecular weight of ~40,000. Composite membranes for direct methanol fuel cells (DMFCs) have been prepared from sulfonated poly(ether ketone quinoline) (SPEEK)-poly(ether ether ketone)(SPEKQ) blend and Nafion with non- and surface coated silicotungstic acid (SiWA). The Nafion/surface coated SiWA composite membranes have excellent potential to be used in DMFCs with a high methanol feed concentration. The surface coated SiWA particles may protect the SiWA particles from "washing out" with water from the feed and suppress methanol crossover. The composite membrane of SPEEK-SPEKQ/SiWA yields a highly porous uniform composite membrane. At a constant feed flow rate, the peak power and current density range increase with respect to the methanol concentration for a Nafion/surface coated SiWA membrane electrode assembly. Peak power of 50mW was achieved for the SPEEK-SPEKQ/SiWA composite membrane.
A Transmission Electron Microscopy Study of Degradation Mechanisms in a Tin-Carbon Fibre Composite Anode for Rechargeable Lithium-Ion Batteries
Authors: Shafiei Mehdi , Alpas Ahmet
Published: October 2011

Electrochemical degradation mechanisms of an Sn-carbon fibre composite anode, fabricated by electrodepositing an ultrafine grain (350 nm) Sn coating on a carbon fibre paper (CFP) and tested in a Li-ion cell, were studied. Using a current density of 1.50 mA cm-2, a reversible planar capacity of 2.96 mAh cm-2 and a capacity retention of 50% after twenty cycles were measured. TEM studies showed that lithiation/ delithiation was not uniform along the diameter of the carbon fibres. Additionally, the lithiation/ delithiation of the Sn coating gradually transformed the initial Sn grains with a (200) orientation to 4 nm-size Sn nanoclusters with a (220) orientation. This created a mixture of nanoparticles with different sizes (4-100 nm) and orientations embedded in an amorphous matrix that filled the micro-pores between the carbon fibres. Thus, the short-range electronic connection in the composite anode was undermined, and a reduction in the cell's capacity occurred.
Voltammetric Study of Fluorenone Complexation by Lewis Acids in an Ionic Liquid
Authors: Cheek Graham T.
Published: October 2011

The complexation of fluorenone by various Lewis acid triflates has been investigated in the ionic liquid 1-butyl-1-methylpyrrolidinium trifluoromethansulfonate (BMPY TfO). Addition of Yb(TfO)3, La(TfO)3, and Sc(TfO)3 produce an approximately 400 mV positive potential shift in the initial fluorenone reduction process. This process occurs as two merged peaks, probably due to fluorenone complexes having varying numbers of triflate ligands. By contrast, Hf(TfO)4 produces a single reduction peak shifted by +1.0 V from uncomplexed fluorenone.
Effect of Nickel Oxide Synthesis Conditions on its Electrochemical Behavior in Alkaline Media
Authors: Spinner Neil , Mustain William E.
Published: October 2011

Nickel oxide (NiO) was synthesized using three different aqueous-phase precipitation methods, and connections were made between physical and electrochemical properties. Room temperature NaOH-precipitated NiO showed the highest electrocatalytic activity for the methanol oxidation reaction and stability among those synthesized. Microcracking and electrode disintegration was associated with the gamma-NiOOH/alpha-Ni(OH)2 redox couple in combination with the oxygen evolution reaction. Carbonate electrolytes have potential as a superior reaction medium to hydroxide, evidenced by 3-4 times higher average current densities and 85% lower charge transfer resistances. In addition, its moderate alkalinity limits electrode and membrane deterioration.
Effect of Atomic Hydrogen in SiNx Films for Gate Dielectric of Silicon-Based TFTs Fabricated at a Low-Temperature(≤150 °) by Cat-CVD
Authors: Keum Ki-Su , Lee Kyoung-Min , Hwang Jae-Dam , No Kil-Sun , Hong Wan-Shick
Published: October 2011

We studied the effect of in-situ hydrogen annealing on dielectric SiNx films at a low-temperature (150 oC) by Cat-CVD. The in-situ hydrogen annealing was performed without a vacuum breaking. After in-situ annealing, furnace annealing was performed for 2hours below 150 oC. The C-V, and I-V characteristics were measured by MIS structure. The high hydrogen ratio sample showed better dielectric properties improvement by annealing. SiNx films dielectric properties were extremely improved by in-situ hydrogen annealing and furnace annealing. Breakdown field was 6 MV/cm. C-V hysteresis window was reduced from 15 V to 1 V. The on/off ratio of TFT was 105. The Mobility was 0.23. We successfully fabricated dielectric SiNx films at the low temperature, and also a-Si TFTs at the same temperature by Cat-CVD.
(Invited) Characterization and Metrology of Nanoclusters-Based Nanostructures
Authors: Pareige Philippe , Roussel M. , Lardé Rodrigue , Pratibha-Nalini R. , Gourbilleau Fabrice , Talbot Etienne
Published: October 2011

Silicon nanoclusters have attracted much interest during the past few years due to their optical and electrical properties (light emission, carrier storage...). These properties are strongly dependent on structural characteristics of nanoclusters (Si-nanoclusters size, distribution, surrounding matrix composition, interface nature...). Thus it is essential to provide characterization procedures which fully describe such systems. Unfortunately, conventional analysis methods such as HRTEM, EFTEM or X-ray diffraction often encounter severe difficulties to measure these parameters. In the present study, Atom Probe Tomography (APT) has been used to investigate structural properties of silicon nanoclusters embedded in silica. We studied SiOx/SiO2 MLs which are composed of 4 nm thick SiOx layers and 4nm thick SiO2 layers containing Si-ncs. Bulk silicon dioxide doped with Erbium and containing Si-ncs dedicated to light amplification has also been studied. We compare data provided by HRTEM, APT and previous studies found in the literature.
Interaction of Nimodipine with DNA Investigated by Electrochemical Methods
Authors: Fang Lei , Wang Wei , He Ping , Du Licheng , Yuan Yanhong
Published: October 2011

The electrochemical behavior of nimodipine and the interaction between nimodipine and calf thymus DNA were investigated by cyclic voltammetry and differential pulse voltammetry. It was shown that nimodipine exhibited an irreversible electrochemical process in 0.50 M ammonia buffer (pH 8.8) at glassy carbon electrode. The anode peak current decreased with increasing concentration of calf thymus DNA and the formal potential shifted negatively, indicating that the interaction between nimodipine and calf thymus DNA was mainly via electrostatic mode and formed a non-electroactive supramolecular compound. The molar binding ratio and association constant of nimodipine with calf thymus DNA were calculated to be 2 and 9.8 × 106, respectively.
Development of Diagnostic Criteria of Rejection Crises in Liver Transplantation by Redox Potential Measurements
Authors: Khubutiya Mogely S. , Goldin Mark M. , Evseev Anatoly K. , Zhao Alexei V. , Salienko Anastasia A.
Published: October 2011

Monitoring of blood serum redox potential (RP) in patients with liver transplants was performed in the course of postoperative treatment. It was observed that abrupt RP shifts of over 25 mV corresponded to the onset of a rejection crisis or other dysfunction of the transplant in the patient. A statistically significant sample of 31 patients with liver transplants was examined, with false positive and false negative results not observed.
Catalytic Activity of TiO2 Nanotubes Modified with Carbon and Pt Nanoparticles for Detection of Dopamine
Authors: Mahshid Sara , Mahshid Sahar S. , Ghahremaninezhad Ahmad , Askari Masoud , Dolati Abolghasem , Yang Lixia , Luo Shenglian , Cai Qingyun
Published: October 2011

Catalytic activity of carbon/Pt nanoparticles modified TiO2 nanotubes electrode was studied by using dopamine contained solutions. The TiO2 nanotubes electrode was prepared using anodizing method in aqueous solution. The electrochemical pulse method was then applied for electrodeposition of Pt nanoparticles onto the TiO2 nanotubes. Further modification was achieved by decomposition of polyethylene glycol in a tube furnace to have a carbon/Pt nanoparticles modified TiO2 nanotubes electrode. The final modified electrode could successfully detect the electro-oxidation of dopamine in a 1mM contained solution using cyclic voltametry method. Also, a high sensitivity towards the oxidation of dopamine in a phosphate buffer solution (pH 7.00) was achieved using the carbon/Pt TiO2 nanotubes electrode. The electro-oxidation currents of dopamine were linearly related to the concentration in range of 1.0×10−6 to 3.5×10−5M. Furthermore, the modified electrode could directly distinguish the oxidation response of dopamine, ascorbic acid and uric acid in their simulations presence.
Electrochemical Features of LiFePO4 Nanoparticles Obtained by Grinding Ingot Synthesized in the Molten State
Authors: Zaghib Karim , Charest Patrick , Dontigny Martin , Guerfi Abdelbast , Trottier J. , Mauger Alain , Julien Christian M.
Published: October 2011

LiFePO4 nano-particles have been prepared by grinding ingot synthesized in the molten state. Formatting 25-nanometer particles was obtained by subsequent jet and wet milling. These primary particles tend to segregate to form secondary particles of size ∼100 nm, for which surface effects become increasingly important. Study of the electrochemical properties of Li//LiFePO4 cells showed that the cell performance appeared to be strongly dependant of the synthetic route used. The best electrode material formed by wet milling followed by 2 wt.% carbon coating delivered discharge capacity of 157 mAh g-1 at C/10 rate without capacity fading after 60 cycles.
Nano-Crystalline TiO2 as Intercalation Electrodes for Li Batteries
Authors: Chiu Kuo-Feng , Lin K. M. , Chen Cheng-Lun , Lin C.C. , Leu Hoang-Jyh
Published: October 2011

Nano-crystalline TiO2 thin films have been fabricated by direct-current sputter deposition. The crystalline TiO2 films are deposited without thermal annealing. The crystal structures, morphologies and electrochemical performances of the fabricated TiO2 electrodes toward lithium have been systematically investigated. By controlling the total deposition pressures and O2 partial pressures, anatase-phase TiO2 electrodes with granular grains and spindle-like grains can be fabricated. The TiO2 electrode exhibits with granular morphology shows short discharge plateau and lower capacity, whereas the spindle-like TiO2 electrode shows a long flat plateau at ~1.7 V with a reversible capacity around 400 mAhg-1 (3.0-0.0 V v.s. Li/Li+ at 0.2 C). The results have demonstrated that the nano-structured spindle-like TiO2 can be used as safe and high capacity electrodes for lithium ion thin film batteries.
Electrochemical Performance of Carbon-Coated HQ-LiFePO4 Cathode
Authors: Ramanathan Mayandi , Ben Mayza Aadil , Ha Seonbaek , Ramani Vijay , Prakash Jai , Zaghib Karim
Published: October 2011

The carbon-coated LiFePO4 Li-ion cathode material was studied for its electrochemical performance. This electrode exhibited a reversible capacity corresponding to more than 86% of the theoretical capacity, when cycled between 2.5V and 4.0V. The positive electrode material displayed excellent capacity retention for prolonged cycling periods and also showed high rate capability upto 5C discharge rates. High power obtained at high discharge rates were attributed to the effects of electronic conductivity improvement enabled by carbon-coating of LiFePO4. Carbon-coating of the electrode was observed as capacitance component in the electrochemical impedance spectra (EIS). Hybrid pulse power characterization (HPPC) tests were also performed on commercial 18650 size cells, using carbon-coated LiFePO4 electrode, to observe the suitability of the positive electrode to HEV applications.
Nano- and Microstructure Design by Mechanochemical Approach of Ceramic Ionic Composites on the Base of SSZ
Authors: Zyryanov Vladimir V. , Uvarov Nikolai F. , Ulihin Artem S.
Published: October 2011

Two series of Sc-stabilized zirconia nanostructured ceramic composites were prepared from mechanochemical origin nanopowders. The first series was obtained by reaction sintering, and the second one by conventional sintering of ceramic powders prepared mechanical activation route. Ceramic samples were studied by complex impedance method and characterized by XRD, SEM with EDX microanalysis. Dense nanostructured ceramics with high conductivity at operation temperature for IT SOFC 900-1000 K were obtained by sintering at 1673 K. The ceramic composites contain mainly cubic phase with minor tetragonal and monoclinic phases. The ordered cracking of grains near the surface with a size of blocks ~20 nm was observed. Cracking near surface and nanostructuring both results from relaxation of mechanical strains related to misfit in volume transformations under cooling of cubic matrix and embedded tetra/monoclinic nanograins. Nano- and microstructure design of composites by mechanochemical ceramic method may become a promising approach in solid state ionics.
Electrocatalytic Activity of Non-Stoichiometric Perovskites toward Oxygen Reduction Reaction in Alkaline Electrolytes
Authors: Yuan Xiao-Zi , Li Xiaoxia , Qu Wei , Ivey Douglas G. , Wang Haijiang
Published: October 2011

Perovskite LaxCa0.4MnO3 (x = 0.4, 0.5, 0.6) powder was prepared through a sol-gel method and characterized by X-ray diffraction (XRD), a gas adsorption technique (BET) and transmission electron microscopy (TEM). The electrocatalytic properties of LaxCa0.4MnO3/C composites towards the oxygen reduction reaction (ORR) were studied using rotating ring-disk electrode (RRDE) techniques and Koutecky-Levich theory in both 1 M and 6 M KOH electrolytes. The results show better ORR activities for non-stoichiometric perovskites than that for stoichiometric La0.6Ca0.4MnO3. The overall electron transfer numbers for these LaxCa0.4MnO3 composites are in the range of 3.2-3.7, and with decreasing values of x the electron transfer number increases and accordingly H2O2 production decreases. These results suggest that the existence of a Mn reduction/oxidation pair in Ca-doped nonstoichiometric perovskites could activate the ORR reaction sites, resulting in improved catalytic activity.
Electrospun Micrometer-Sized Sulfur Fibers as an Active Material for Lithium Batteries
Authors: Tsutsumi Hiromori , Sunada Kazuki
Published: October 2011

We prepared micrometer-sized sulfur fibers by melt-electrospinning technique. The typical average size of the spun fibers was 17.8 μm in diameter. The XRD pattern of the as-spun sulfur fibers suggests that their crystal structure is polymeric sulfur. The polymeric sulfur structure of the fibers left at room temperature for 24 h changed to orthorhombic α-S8 structure. The coating process of the spun sulfur fibers with poly(pyrrole), PPy, was performed through oxidative coupling reaction of pyrrole by iodine. Coating of the sulfur fibers with PPy enhanced their electrochemical responses. The capacity of the PPy-coated spun sulfur fiber electrode in the lithium-sulfur test cell was 570 Ah kg-1 under constant current discharge condition (0.045C).
Synthesis and Characterization of Carbon Nanotube Electrodes Grown by Thermal Chemical Vapor Deposition
Authors: Smart Christopher J. , Pearce Matthew A. , Oh Scott P. , Hudson Reuben , Alles Alexander , Kaur Saranjit , Belli Stuart L.
Published: October 2011

We have developed a method for the growth of electrically conductive nanotubes directly on a wire electrode. The nanotube layer is deposited by thermal CVD on a nickel or cobalt catalyst layer on gold or copper wires. The nanotubes can be subsequently decorated with a variety of metals by electroplating. Metal deposits are observed to be selective for the ends of nanotubes or for defect sites. The nanotube films have been characterized by SEM, elemental analysis, and Raman spectroscopy.
Elastic Characteristics of Nanocomposites Based on Multiwalled Carbon Nanotubes and Polypropylene
Authors: Onanko Anatoliy P. , Lyashenko Oleg , Onanko Y. A.
Published: October 2011

The carbon nanotubes and polypropylene total deformation consists of elastic and inelastic constituents ε∑ = εE + εIE. Inelastic deformation εIE is conditioned motion of dislocations. Elastic deformation εE takes a place "instantly". The absolute value of the elastic module E, elasticity limit σE, inelasticity limit σ0.2, ultimate stress limit σS of the composites carbon nanotubes 5% + polypropylene, carbon nanotubes 0,5% + polypropylene, carbon nanotubes 0,1% + polypropylene were determined.
The Role that Internal Metals Play in Endohedral Metallofullerenes
Authors: Lu Xing , Lian Y. , Nikawa Hidefumi , Mizorogi Naomi , Slanina Z. , Akasaka Takeshi , Nagase Shigeru
Published: October 2011

Position and motion of the internal metals in endohedral metallofullerenes show significant influences, via strong metal-cage interactions, on the structures and properties, especially the chemical reactivity, on the whole molecules. First, the cages structures of the resulting endohedrals are evidently dictated by the encapsulated metallic species, even when only one metal is inside (e.g. Yb@C2n). Then, the motional behavior of the internal cluster is sometimes highly temperature sensitive, and it is effective enough to alter the whole molecular symmetry (e.g. Sc2C2@C80). Moreover, the encapsulated metals can also differentiate the chemical reactivity of cage carbons (e.g. Y@C82), while the paramagnetic species always tend to pursue a close-shell electronic configuration whenever possible (e.g. La@C2n). Finally, the [5,5]-carbons in non-IPR metallofullerenes are effectively stabilized by the internal metals via strong coordination which can be probed by exohedral modification (e.g. La2@C72).
(Invited) Toxicity Studies on Carbon Nanotubes: State of the Art
Authors: Kolosnjaj Jelena , Szwarc Henri , Moussa Fathi
Published: October 2011

The growing use of carbon nanotubes (CNTs) and their mass production have raised questions about their safety and environmental impact. Studies evaluating the toxicity of CNTs have begun about a decade ago and their results are controversial, both in vitro and in vivo. This is due to several parameters, namely structure, size distribution, surface area, surface defects and charge, agglomeration state and purity. Available data clearly shows that nanotubes may be internalized into cells, where they can possibly have harmful effects. Moreover, when nanotubes reach living organisms, they can, under some conditions, induce inflammatory and granulomatous reactions. Here we have gathered and compared the results of some toxicity studies that have been performed up to date, in order to give an overview of the current knowledge.
Proton Diffusion in Anhydrous Nafion-Blend Membrane for High Temperature PEFCs
Authors: Tanaka Yoshinori , Kim Je-Deok , Tateyama Yoshitaka , Inoue Junichi , Kojima Natsuko , Jimura Keiko , Hayashi Shigenobu , Jun Mun-Suk , Mori Toshiyuki , Ohono Takahisa
Published: October 2011

Proton diffusion in an anhydrous membrane, perfluorosulfonic acid (Nafion)-1,2,3-triazole blend membrane, was examined by Car-Parrinello molecular dynamics. In the model blend membrane, alternative roles of water by 1H-1,2,3-triazole were observed. Cluster structure of 1H-1,2,3-triazole in the model was different from that of calculated bulk state. Quasi-two-dimensional hydrogen chains in the bulk transformed to organic three-dimensional in our model. Along the multiple hydrogen chains, Grotthuss type hydrogen hopping occurred. Calculated self diffusion coefficients of hydrogen in the model blend membrane were faster than that of the bulk and the values were comparable with that of bulk water.
Capacitance Properties of Natural Mineral Covellite in Strong Alkaline Solution
Authors: Stević Zoran , Rajčić-Vujasinović Mirjana M. , Bugarinović Sanja
Published: October 2011

Electrochemical characteristics of copper sulfides are of importance because of their possible application as an active material in solar cells. Also, investigation of behavior of copper sulfide minerals during their anodic polarization and modeling of these reactions suggest that the equivalent electrical circuit must contain very high capacitances, indicating a possibility of using copper sulfide minerals for electrochemical supercapacitor electrodes.
Fast Lithium-Ion Conducting Garnet-Like Electrolytes for Potential Application in Lithium Ion Batteries
Authors: Narayanan Sumaletha , Thangadurai Venkataraman
Published: October 2011

In this paper, we report the effect of Y-doping for Nb in the garnet-like Li5La3Nb2O12 on Li-ion conductivity. The phase formation, microstructure and electrical conductivity studies were done using powder X-ray diffraction (PXRD), scanning electron microscopy (SEM), 7Li nuclear magnetic resonance (Li-NMR) and AC impedance spectroscopy. The formation of cubic garnet-like structure was observed for x up to 0.25 and additional impurity peaks were observed above x = 0.25 in Li5La3Nb2-xYxO12-δ. 7Li MAS NMR exhibits a single peak close to a chemical shift value of 0 ppm with respect to LiCl which could be due to the fast conduction of Li ions. Lithium ion conductivity of 1.34 x 10-5 and 1.44 x 10-5 Scm-1 was observed for x = 0.05 and 0.1 members, respectively at 23 °C in air.
A Multi-Scale Electrochemical and Thermal Model of a LiFePO4 Battery
Authors: Hellwig Christian , Sörgel Seniz , Bessler Wolfgang G.
Published: October 2011

Modeling and simulation of lithium batteries is becoming of in-creasing importance both for improving the fundamental under-standing of electrochemical processes and for developing battery management systems for practical applications. We present a 1D+1D+1D multi-scale electrochemical and thermal model of a lithium-ion battery with lithium iron phosphate (LiFePO4, LFP) positive electrode material. The model uses a hierarchical repre-sentation of spatial scales: On the nanoscopic level, diffusive transport takes place in the active material particles. On the micro-scopic level, multi-component mass and charge transport as well as heat production is described in a single repeat unit (anode, separa-tor, cathode, current collectors). On the macroscopic scale, the model describes heat transport in the radial direction of a cylindri-cal cell. Molar enthalpies and entropies are incorporated as func-tion of state of charge (SOC) for reliable simulation of heat pro-duction. The model is validated using experimentally-determined discharge curves over a wide range of discharge currents.
Highly Flexible Temperature Tolerant Anhydrous Nafion-1,2,3-Triazole Blend Membranes Synthesized by Autoclave Solution Processing
Authors: Kim Je-Deok , Jun Mun-Suk , Nishimura Chikashi , Choi Young-Woo
Published: October 2011

This paper was investigated for the properties of Nafion-1,2,3-triazole blend membranes by room temperature (RT) and autoclave (AC) solution processing with different weight percent. Both blend membranes were very flexible, transparent, and homogeneous. To get the high proton conductivity, it was required an AC solution processing at the temperature of 200oC. The conductivity of the blend membranes using AC was one order higher than that of RT solution processing. The elementary analysis of the blend membrane using AC solution processing showed higher hydrogen concentration than that of RT solution processing. 1H NMR of the blend solution using AC solution processing showed the chemical shifts of not only Nafion solution and 1,2,3-triazole but also new products. The Nafion-1,2,3-triazole blend membranes showed a thermal stability up to 200oC from cycle properties by differential scanning calorimetry (DSC).
Using Artificial Neural Networks to Predict Direct Solar Irradiation
Authors: Mubiru James
Published: October 2011

This paper explores the possibility of developing a prediction model using artificial neural networks (ANNs), which could be used to estimate monthly average daily direct solar radiation for locations in Uganda. Direct solar radiation is a component of the global solar radiation and is quite significant in the performance assessment of various solar energy applications. Results from the paper have shown good agreement between the estimated and measured values of direct solar irradiation. A correlation coefficient of 0.998 was obtained with mean bias error of 0.005 MJ/m2 and root mean square error of 0.197 MJ/m2. The comparison between the ANN and empirical model emphasized the superiority of the proposed ANN prediction model. The application of the proposed ANN model can be extended to other locations with similar climate and terrain.
E‐Cadherin/β‐Catenin Complex and the Epithelial Barrier
Authors: Tian Xinrui , Liu Zhuola , Niu Bo , Zhang Jianlin , Tan Thian Kui , Lee So Ra , Zhao Ye , Harris David C. H. , Zheng Guoping
Published: October 2011

E‐Cadherin/β‐catenin complex plays an important role in maintaining epithelial integrity and disrupting this complex affect not only the adhesive repertoire of a cell, but also the Wnt‐signaling pathway. Aberrant expression of the complex is associated with a wide variety of human malignancies and disorders of fibrosis resulting from epithelial‐mesenchymal transition. These associations provide insights into the complexity that is likely responsible for the fibrosis/tumor suppressive action of E‐cadherin/β‐catenin.
Behavioral Differentiation and Ovarian Development of Unmated Gynes, Queens, and Workers ofEctatomma vizottoiAlmeida 1987 (Formicidae, Ectatomminae)
Authors: Vieira Alexsandro Santana , Fernandes Wedson Desidério , Antonialli-Junior William Fernando
Published: October 2011

Behavioral differentiation and ovarian development of unmated gynes, queens, and workers ofEctatomma vizottoiwere investigated in laboratory conditions. Forty-one behavioral acts were identified and quantified for workers, 19 for queens and 24 for unmated gynes, for an overall species repertoire of 42 different behavioral acts. Ovipositing reproductive eggs was an exclusive task of the queen, whereas workers showed 15 caste-specific behaviors. The most important (frequent) behaviors for the queens were brood care, immobility, and reproduction, and for workers were immobility, grooming/interaction, brood care, and foraging. Unmated gynes (not winged) primarily showed immobility, brood care, grooming/interaction, and foraging. Analysis of ovarian development showed that unmated gynes had little-developed ovarioles, in contrast to queens. Queens and unmated gynes showed a clear behavioral differentiation, in which queens played the role of reproducers and unmated gynes performed activities belonging to the worker repertoire. Despite the presence of several breeding queens in the colony, functional monogyny was the rule.
Antioxidant and Anti-Inflammatory Effects of Exercise in Diabetic Patients
Authors: Golbidi Saeid , Badran Mohammad , Laher Ismail
Published: October 2011

Diabetes is a chronic metabolic disease which is characterized by absolute or relative deficiencies in insulin secretion and/or insulin action. The key roles of oxidative stress and inflammation in the progression of vascular complications of this disease are well recognized. Accumulating epidemiologic evidence confirms that physical inactivity is an independent risk factor for insulin resistance and type II diabetes. This paper briefly reviews the pathophysiological pathways associated with oxidative stress and inflammation in diabetes mellitus and then discusses the impact of exercise on these systems. In this regard, we discuss exercise induced activation of cellular antioxidant systems through “nuclear factor erythroid 2-related factor.” We also discuss anti-inflammatory myokines, which are produced and released by contracting muscle fibers. Antiapoptotic, anti-inflammatory and chaperon effects of exercise-induced heat shock proteins are also reviewed.
Gene Expression Profiling in Multiple Myeloma—Reporting of Entities, Risk, and Targets in Clinical Routine
Authors: Meißner Tobias , Seckinger Anja , Rème Thierry , Hielscher Thomas , Möhler Thomas , Neben Kai , Goldschmidt Hartmut , Klein Bernard , Hose Dirk
Published: October 2011

Purpose: Multiple myeloma is an incurable malignant plasma cell disease characterized by survival ranging from several months to more than 15 years. Assessment of risk and underlying molecular heterogeneity can be excellently done by gene expression profiling (GEP), but its way into clinical routine is hampered by the lack of an appropriate reporting tool and the integration with other prognostic factors into a single “meta” risk stratification.

Experimental Design: The GEP-report (GEP-R) was built as an open-source software developed in R for gene expression reporting in clinical practice using Affymetrix microarrays. GEP-R processes new samples by applying a documentation-by-value strategy to the raw data to be able to assign thresholds and grouping algorithms defined on a reference cohort of 262 patients with multiple myeloma. Furthermore, we integrated expression-based and conventional prognostic factors within one risk stratification (HM-metascore).

Results: The GEP-R comprises (i) quality control, (ii) sample identity control, (iii) biologic classification, (iv) risk stratification, and (v) assessment of target genes. The resulting HM-metascore is defined as the sum over the weighted factors gene expression–based risk-assessment (UAMS-, IFM-score), proliferation, International Staging System (ISS) stage, t(4;14), and expression of prognostic target genes (AURKA, IGF1R) for which clinical grade inhibitors exist. The HM-score delineates three significantly different groups of 13.1%, 72.1%, and 14.7% of patients with a 6-year survival rate of 89.3%, 60.6%, and 18.6%, respectively.

Conclusion: GEP reporting allows prospective assessment of risk and target gene expression and integration of current prognostic factors in clinical routine, being customizable about novel parameters or other cancer entities. Clin Cancer Res; 17(23); 7240–7. ©2011 AACR.
Isolated Low Levels of High-Density Lipoprotein Cholesterol Are Associated With an Increased Risk of Coronary Heart Disease
Authors: Huxley Rachel R. , Barzi Federica , Lam Tai Hing , Czernichow Sebastien , Fang Xianghua , Welborn Tim , Shaw Jonathan , Ueshima Hirotsugu , Zimmet Paul , Jee Sun Ha , Patel Jeetesh V. , Caterson Ian , Perkovic Vlado , Woodward Mark ,   for the Asia Pacific Cohort Studies Collaboration and the Obesity in Asia Collaboration
Published: October 2011

Background—

Previous studies have suggested that there is a novel dyslipidemic profile consisting of isolated low high-density lipoprotein cholesterol (HDL-C) level that is associated with increased risk of coronary heart disease, and that this trait may be especially prevalent in Asian populations.

Methods and Results—

Individual participant data from 220 060 participants (87% Asian) in 37 studies from the Asia-Pacific region were included. Low HDL-C (HDL <1.03 mmol/L in men and <1.30 mmol/L in women) was seen among 33.1% (95% confidence interval [CI], 32.9–33.3) of Asians versus 27.0% (95% CI, 26.5–27.5) of non-Asians (
P
<0.001). The prevalence of low HDL-C in the absence of other lipid abnormalities (isolated low HDL-C) was higher in Asians compared with non-Asians: 22.4% (95% CI, 22.2–22.5) versus 14.5% (95% CI, 14.1–14.9), respectively (
P
<0.001). During 6.8 years of follow-up, there were 574 coronary heart disease and 739 stroke events. There was an inverse relationship between low HDL-C with coronary heart disease in all individuals (hazard ratio, 1.57; 95% CI, 1.31–1.87). In Asians, isolated low levels of HDL-C were as strongly associated with coronary heart disease risk as low levels of HDL-C combined with other lipid abnormalities (hazard ratio, 1.67 [95% CI, 1.27–2.19] versus 1.63 [95% CI, 1.24–2.15], respectively). There was no association between low HDL-C and stroke risk in this population (hazard ratio, 0.95 [95% CI, 0.78 to 1.17] with nonisolated low HDL-C and 0.81 [95% CI, 0.67–1.00] with isolated low HDL-C).

Conclusion—

Isolated low HDL-C is a novel lipid phenotype that appears to be more prevalent among Asian populations, in whom it is associated with increased coronary risk. Further investigation into this type of dyslipidemia is warranted.
Biomarkers of Left Ventricular Hypertrophy and Remodeling in Blacks
Authors: Coutinho Thais , Al-Omari Malik , Mosley Thomas H. , Kullo Iftikhar J.
Published: October 2011

Left ventricular (LV) hypertrophy, a marker for adverse cardiovascular events, is more common in blacks than in non-Hispanic whites. Mechanisms leading to LV hypertrophy and mediating its clinical sequelae in blacks are not fully understood. We investigated the associations of 39 candidate biomarkers in distinct biological pathways with LV mass and geometry in blacks. Participants included 1193 blacks (63±9 years of age; 72% women; 78% hypertensive) belonging to hypertensive sibships. LV mass was measured by transthoracic echocardiography and indexed to height.
2.7
LV geometry was categorized as normal, concentric remodeling, concentric hypertrophy, and eccentric hypertrophy. Generalized estimating equations were used to assess associations of the 39 biomarkers with LV mass index after adjustment for age, sex, and conventional risk factors. After adjustment for potential confounders, log-transformed levels of the following biomarkers were independently associated with LV mass index: N-terminal pro-brain natriuretic peptide (β±SE=0.07±0.01 pg/mL;
P
<0.0001), mid-regional pro-atrial natriuretic peptide (β±SE=0.08±0.02 pmol/L;
P
<0.0001), mid-regional pro-adrenomedullin (β±SE=0.09±0.03 nmol/L;
P
=0.0006), C-terminal pro-endothelin (β± SE=0.05±0.02 pmol/L;
P
=0.0009), and osteoprotegerin (β±SE=0.07±0.02 pg/mL;
P
=0.0005) (β is for 1 log increase in biomarker level). The associations of these biomarkers with LV mass index were mainly due to their association with eccentric hypertrophy. Higher circulating levels of natriuretic peptides, adrenomedullin, endothelin, and osteoprotegerin were associated with increased LV mass index, providing insights into the pathophysiology of LV hypertrophy in blacks.
Predictability Associated with Nonlinear Regimes in an Atmospheric Model
Authors: Peters John M. , Kravtsov Sergey , Schwartz Nicholas T.
Published: October 2011

Atmospheric regimes are midlatitude flow patterns that persist for periods of time exceeding a few days. Here, the authors analyzed the output of an idealized atmospheric model (QG3) to examine the relationship between regimes and predictability.

The regimes were defined as the regions of the QG3 phase subspace characterized by excess persistence probability relative to a benchmark linear empirical model (EMR) for geographically two-dimensional and then zonally averaged flow patterns. The regimes identified correspond to the opposite phases of the Arctic Oscillation (AO+ and AO−) and to a more regional pattern reflecting the positive phase of the North Atlantic Oscillation (NAO+).

For all of these phase-space regime regions, the leading modes of the QG3 state vector decay to climatology at a slower rate than predicted by the EMR, which contributes to the maintenance of non-Gaussian regime anomalies. Predictable regimes are connected to “regime precursor” regions of the phase space, from which trajectories flow into regime regions following mean phase-space velocities. Packets of trajectories originating from these regions are characterized by anomalously low spreading rates due to a combination of low local stochastic diffusivity and convergence of the nonlinear component of mean phase-space velocities along the trajectory pathways. While unpredictable regimes do have precursor regions, trajectories emanating from these regions are characterized by relatively high spreading rates.

The predictable regimes AO+ and AO− are insensitive to the metric used to identify the regimes; however, the unpredictable regime NAO+ in the 2D space is not directly associated with its zonal-metric counterpart.
On the Relationship between Thermodynamic Structure and Cloud Top, and Its Climate Significance in the Arctic
Authors: Sedlar Joseph , Shupe Matthew D. , Tjernström Michael
Published: October 2011

Cloud and thermodynamic characteristics from three Arctic observation sites are investigated to understand the collocation between low-level clouds and temperature inversions. A regime where cloud top was 100–200 m above the inversion base [cloud inside inversion (CII)] was frequently observed at central Arctic Ocean sites, while observations from Barrow, Alaska, indicate that cloud tops were more frequently constrained to inversion base height [cloud capped by inversion (CCI)]. Cloud base and top heights were lower, and temperature inversions were also stronger and deeper, during CII cases. Both cloud regimes were often decoupled from the surface except for CCI over Barrow. In-cloud lapse rates differ and suggest increased cloud-mixing potential for CII cases.

Specific humidity inversions were collocated with temperature inversions for more than 60% of the CCI and more than 85% of the CII regimes. Horizontal advection of heat and moisture is hypothesized as an important process controlling thermodynamic structure and efficiency of cloud-generated motions. The portion of CII clouds above the inversion contains cloud radar signatures consistent with cloud droplets. The authors test the longwave radiative impact of cloud liquid above the inversion through hypothetical liquid water distributions. Optically thin CII clouds alter the effective cloud emission temperature and can lead to an increase in surface flux on the order of 1.5 W m−2 relative to the same cloud but whose top does not extend above the inversion base. The top of atmosphere impact is even larger, increasing outgoing longwave radiation up to 10 W m−2. These results suggest a potentially significant longwave radiative forcing via simple liquid redistributions for a distinctly dominant cloud regime over sea ice.