bluuebunny/crossref_metadata_2025 huggingface dataset:
Tortuosity of Binder-Free and Carbon-Free High Energy Density LiCoO2 Electrodes for Rechargeable Lithium-Ion Batteries
Authors: Cobb Corie Lynn , Bae Chang-Jun
Published: April 2014

Conventional electrodes, by volume, contain a large amount of electrochemically inactive material such as binder and carbon. This lowers the overall capacity of a battery and makes it difficult to realize high volumetric energy. Researchers have been actively pursuing methods which will enable the fabrication and full utilization of thick electrodes (≥200µm) with a minimal amount of inactive material. One approach which has emerged is to fabricate thick sintered electrode structures which are free of binder and carbon. However, these structures do not adhere to conventional assumptions about tortuosity. This paper aims to correlate John Newman’s macrohomogeneous porous electrode model to thick high energy density, carbon-free and binder-free sintered electrode samples fabricated at PARC. We examine how assumptions about tortuosity affect model predictions of capacity. Our efforts focus on understanding the model parameters which can be used in Newman’s existing model without modification to the underlying equations.
Simulation of Electrolyte Composition Effects on High Energy Lithium-Ion Cells
Authors: Spotnitz Robert , Gering Kevin L. , Hartridge Steve , Damblanc Gaetan
Published: April 2014

A physics-based simulation model is used to characterize the effect of different LiPF6-based electrolyte systems on discharge energy of a high energy cell design at temperatures of -25, 0, 25 and 50°C and rates of C/10, C/5, C/2, C, and 2C. At 0°C and above at discharge rates below C/5, the electrolyte has almost no effect. The electrolyte properties only become important at high discharge rates and especially at low temperatures. The conductivity and diffusivity are highly correlated, though the correlation becomes slightly weaker at low temperatures. At rates that severely reduce utilization of cell energy, the diffusivity becomes the key parameter to correlate with discharge energy, else the concentration conductivity correlates best.
The Effect of Linear Carbonates on HF Formation in LiPF6-based Electrolytes
Authors: Imholt Laura , Lux Simon Franz , Meyer Hinrich Wilhelm , Winter Martin , Kostecki Robert
Published: April 2014

The influence of the concentration of the linear carbonates in a LiPF6-based mixed organic carbonate electrolyte on the electrolyte degradation at elevated temperatures was investigated using a novel experimental set-up. The HF formation upon the salt decomposition at 60°C was monitored with spectroscopic ellipsometry by measuring the etching rate of a silicon dioxide thin-film in the electrolyte. The rate of the SiO2 film thickness decrease is proportional to the concentration of the linear carbonate solvent in the electrolyte.
(Invited) Wafer Scale Copper Direct Plating on Thin PVD RuTa Layers: A Route to Enable Filling 30 nm Features and Below
Authors: Armini Silvia , El-Mekki Zaid , Nagar Magi , Radisic Alex , Ruythooren W. , Vereecken Philippe M.
Published: April 2014

Among all the Ru-based substrates, mixed-phase RuTa liners grown by physical vapor deposition have been explored as potential directly-platable diffusion barrier candidates. In order to understand the full-wafer copper direct plating process that occurs on these liners, the effect of the applied waveform, electrical contacts and suppressor chemistry have been investigated. In order to enhance copper nucleation and wafer scale edge-to-center copper front propagation rate, a liner surface cleaning protocol is developed. The copper front propagation across the 300 mm wafer is reported as a function of the RuTa film thickness. An optimized copper direct plating process on RuTa layers as thin as 4 nm is integrated in 90 and 30 nm half pitch single and dual damascene structures. Results in terms of compatibility of the direct plated copper with the following chemical mechanical planarization step complemented with physical and electrical characterization data are reported. The direct filling of ~25 nm sacrificial fin structures is also investigated.
Electrodeposited Cu Film Morphology on Thin PVD Cu Seed Layers
Authors: Kelly James , Lin Xuan , Nogami Takeshi , van der Straten O. , Demarest James , Li Juntao , Murphy Richard , Zhang Xunyuan , Penny Christopher , Parks C. , DeHaven Patrick , Madan Anita , Edelstein Daniel
Published: April 2014

The electrodeposited Cu film morphology on thin physical vapor deposited (PVD) Cu seed for various conditions is discussed. Thinner PVD Cu seed on Ta yields isolated electrodeposited Cu particles, while smooth plated films are obtained for thicker seed. Changes in virgin makeup solution (VMS) concentrations have a limited impact on the morphology of Cu electrodeposited on thin Cu seed. Increased seed to plate queue time appears to lead to coarser, more isolated deposited Cu particles. A chemical vapor deposited (CVD) Co liner appears to improve the effective thickness of PVD Cu seed and hence the electrodeposited Cu film morphology for conditions considered in this study.
Investigation on Pad Surface Conditioner to Control Dishing Amount in Cu Damascene Process
Authors: Kim Jongwon , Kim Hojoong , Hong Seokji , Hwang Hasub
Published: April 2014

In the Cu damascene chemical mechanical planarization (CMP) process, dynamic interaction of wafer and pad surfaces is a mechanism of material removal to prepare flat layer on wafer surface. During the interaction, chemical and mechanical effects are working at the same time to get the desired surface. Because, polishing pad has elastic characteristic, pad asperity in contact with wafer surface might be deformed and chemically reacts only at pattern trench area where Cu is filled. Thus, a resulted phenomenon called ‘dishing’ occurs. To control Cu pattern dishing, in present study, we observed the dishing amount variation by modifying polishing pad surface which was dressed by pad conditioners in different design. It is resulted that the number of contact between pad asperity and wafer surface is a key factor to suppress dishing phenomenon during Cu damascene CMP process.
Improvement of Adhesion Strength of Electroless Barrier Layer and Its Application to TSV Process
Authors: Nishizawa Shoichiro , Inoue Fumihiro , Shimizu Tomohiro , Shingubara Shoso
Published: April 2014

The all-wet process for TSV-fill utilizing electroless barrier and seed technologies prior to electroplating of Cu is promising methods to realize low-cost and highly reliable Cu-filled TSVs for 3-D integration of Si. Although there have been numerous studies to form electroless barrier layers such as Co- and Ni- alloys, poor adhesion of these barrier layers have been a serious problem. In this study, we studied effect of various additives on the adhesion strength of electroplated CoWB film. It is shown that addition of saccharine, which has both sulfone- and amino- groups, significantly improved adhesion strength.
Low Temperature Wafer Bonding for 3D Applications
Authors: Burggraf Juergen , Bravin Julian , Wiesbauer Harald , Dragoi Viorel
Published: April 2014

Due to the high process temperature required for fusion bonding (e.g. ~1000°C) this process was not attractive for 3D applications. In the recent years low temperature fusion bonding processes were developed for addressing low temperature applications. A low temperature CMOS compatible fusion bonding process based on plasma activation of the substrate surfaces prior bonding was developed. The low temperature fusion bonding process was used in combination with standard thin wafer manufacturing processes in order to enable and demonstrate thin layer wafer bonding with subsequent multi-layer stacking capability. The process is compatible with the high cleanliness levels required by CMOS technology and can be used for various application scenarios involving through-silicon vias (TSV) technology.
Analysis of Cu(I) Complexes in Copper Sulfate Electroplating Solution by Using Reaction Kinetics with a Chelate Reagent
Authors: Noma Hiroaki , Koga Toshiaki , Hirakawa Chieko , Nonaka Kazuhiro , Shobu Kazuhisa , Kaibuki Tadahiro , Moriyama Syusaku
Published: April 2014

Analysis of Cu(I) in copper sulfate electroplating solutions was conducted by absorption of a chelate of Cu(I) with bathocuproinedisulfonic acid, disodium salt (BCS). The absorbance of the color reaction of Cu(I) increased quickly in a few minutes after mixing with the chelate reagent and subsequently continued to increase slowly. To analyze the reaction kinetics of the color reaction, we divided Cu(I) complexes into two groups, small complexes and large Cu(I)-PEG complexes, and assumed the reaction of each group of complexes and BCS is a first order reaction with a specific reaction rate constant. We simulated the absorption curve with a good correlation and obtained the concentrations and the time constants, inverse of rate constants, of small complexes and large Cu(I)-PEG complexes. These concentrations and time constants are important parameters to control plating solutions. The time constant of small complexes can be attributed to the variation of the proportions of these small complexes. The smaller time constant of Cu(I)-PEG complexes can be considered the larger size distribution of Cu(I)-PEG with different chain lengths. Using this analysis, we monitored the variation of Cu(I) concentration in production lines for one month and found the increase of small complexes during the resting state of the lines. This increase corresponded to the tendency of occurring of brightening troubles.
Cuprous Ion As An Accelerant of Copper Damascene Electrodeposition
Authors: Kondo Kazuo , Kouta Hamazaki , Yokoi Masayuki , Okamoto Naoki , Saito Takeyasu , Hayashi Taro
Published: April 2014

Free cuprous formed inside trench accelerates trench via bottom. A drastic increase in current has been measured with N2 bubbling by initially dissolving the copper of the trench bottom electrode. The current densities increase with the narrower trench bottom electrode width. With O2 bubbling, the currents show a very low value and no difference in the trench bottom electrode width. These drastic differences in current densities with the O2 gas concentration in the electrolyte must be caused by the cuprous complex formed in the trench of the trench bottom electrode. The cuprous complex is free and not adsorbed by the electrode. For the basic bath with only Cl-, the current shows a marked increase. Cl- is an important additive for the acceleration, and the acceleration must be related to the free cuprous complex and electron bridge formation of Cl-. The constant potential measurements without dissolving the copper electrode, also, show that the free cuprous complex formed through electrodeposition is the accelerant.
Effect of Basicity of Amino Group at Side Chain in Diallylamine-Type Copolymer Additive on Via-Filling by Copper Electrodeposition
Authors: Yamada Yasutaka , Kondo Kazuo , Takeuchi Minoru , Okamoto Naoki , Saito Takeyasu , Bunya Masaru , Yokoi Y.
Published: April 2014

We achieved the bottom-up via-filling by copper electrodeposition using a single diallylamine-type copolymer additive instead of the four types of additives, Suppressor Leveler Accelerator and Chloride ions. We newly synthesized and used four additives modified side chains to research more the function of this additive. We observed vias cross sections, performed an electrochemical analysis and conducted quartz crystal microbalance (QCM) measurements. By comparing the amino group at the end of the side chain with the one near the main chain, it was found the basicity of the latter is weak due to the neighboring group effect. However, when the distance between these two amino groups is long, the basicity of the amino group near the main chain is strong. The use of a polymer additive with a strong amino group near the main chain had the effect of suppressing the electrodeposition outside vias and achieving a good bottom-up filling.
Semiconductors for Photovoltaic Devices: Electrochemical Approaches Using Ionic Liquids
Authors: Dale Phillip J. , Malaquias João C. , Steichen Marc
Published: April 2014

Thin film photovoltaic devices offer similar power conversion efficiencies to polycrystalline silicon devices and consist of a p-n heterojunction. Electrodeposition allows the deposition of large area thin films with high material usage, low energy costs, and potentially at high speed. Therefore, can electrodeposition be used to grow high quality p-type compound semiconductors? Normally, a two-step approach of precursor formation by aqueous electrodeposition followed by annealing is taken. Aqueous electrodeposition has the disadvantage of a narrow electrochemical window and relatively low deposition temperatures. The narrow window hinders the electrodeposition of elements with negative reduction potentials. The direct deposition of semiconductors at low temperatures leads to deposits with deficient properties. Ionic liquids offer larger electrochemical windows and higher deposition temperatures. Their use in the direct preparation of p-type SnS and the electrodeposition of a Cu/In-Ga precursor for Cu(In,Ga)Se2 is explored. A future perspective of high-speed electrodeposition by designer ionic liquids is given.
PEM Electrolysis Simulation and Validation
Authors: Fritz David L , Mergel Jürgen , Stolten Detlef
Published: April 2014

To meet the ever-growing demand for polymer electrolyte membrane (PEM) electrolyzers to operate at higher current densities, higher pressures and higher temperatures, a zero dimensional simulation was developed to optimize operating conditions and cell geometries. The model presented was focused on capturing the performance of an electrolyzer operating at higher current densities ranging from 2-6 A/cm2. This entails focusing more on the mass transport and ohmic losses (both proton and electron transport) that dominate under these conditions. Removing a gas from the catalyst layer can be much easier than removing a liquid due to the lower densities and higher diffusivities, thus reducing the onset of mass transport losses. This is what allows the PEM electrolyzer to operate at high current densities when compared to PEM fuel cells, however, it prompts changes in how the mass transport losses should be accounted for. A design tool was developed to optimize operational and geometrical parameters of a PEM electrolyzer. Models with a strong focus on ohmic losses and prediction of membrane proton transport were combined to improve the prediction of the ohmic losses. These are particularly important when operating at high current densities due to the linear dependence ohmic losses have with current density. This model is then validated under various operating conditions. A separator plate/flow field design optimization was performed and conducted with the goal of maximizing the conductive contact areas.
Electrochemical Performance of Ultrafine Bubble Water
Authors: Ueda Yoshikatsu , Tokuda Yomei , Zushi Takahiro
Published: April 2014

The electrochemical performance of ultrafine bubble (UFB) water , is reported herein. Recently, UFB has found applications in various fields, However, the detailed mechanism underlying the performance of UFB is not known, although the relevance of ions (proton and hydroxide ion) in solution has been discussed. Therefore, we investigated UFB through electrochemical measurements. First, we conducted a preliminary experiment in an ultrafine bubble generator (BUVITAS HYK-32-D, KYOWA KISETSU) and a measuring device for the concentration of microparticles (NANOSIGHT LM-10, Quantum Design, Inc.) . We also measured the electrical conductivity (S230, Mettler Toledo) and pH (LAQUA F-73, Horiba co. Ltd.) and found that the amount of flowing gas and the gas species did not influence the UFB concentration.
Influence of the sp2 Content on Boron Doped Diamond Electrodes Applied in the Textile Dye Electrooxidation
Authors: Migliorini Fernanda Lanzoni , Alegre Marcela Dalprat , Alves Suellen Aparecida , Lanza Marcos Roberto Vasconcelos , Baldan Mauricio Ribeiro , Ferreira Neidenei Gomes
Published: April 2014

This work presents the production, and the characterization of Boron-doped diamond (BDD) films deposited on Titanium (Ti) substrate (BDD/Ti) with different sp2 contents. The electrooxidation of the dye Reactive Orange 16 (RO16) is studied systematically considering the sp2 bonds influence. The results for the dye electrochemical degradations were investigated by spectroscopic techniques UV/VIS analysis, Total Organic Carbon (TOC), and High Performance Liquid Chromatography (HPLC). The BDD electrode with the lowest percentage of CH4 showed the best efficiency for the aromaticity reduction, the reduction of solution color and in the analysis of the TOC. This performance was associated to its best diamond purity. This study also demonstrated that there is a compromise between the conductivity of the films and the increase of bonds sp2 type.
Effect of Cerium Doping on Morphology and Physical Properties of α-Fe2O3 Films Prepared by Hydrothermal Electrodeposition
Authors: Yilmaz Ceren , Unal Ugur
Published: April 2014

In this study, electrochemical growth of Ce-doped α-Fe2O3 films is reported. Electrodeposition at 75°C and also a combined hydrothermal-electrochemical method to obtain hematite are presented. Both acidic and neutral plating solutions were used for the depositions. Ferric oxyhydroxide is produced by electrodeposition at 75°C and converted to hematite phase after annealing. Hydrothermal-electrodeposition at 130°C results in formation of hematite phase directly. The effect of temperature, deposition solution and cerium ion amount on the morphology and physical properties of hematite films are characterized.
A Fluidised Cathode Process for the Electrochemical Reduction of Tungsten Oxide in A Molten LiCl-KCl Eutectic
Authors: Abdulaziz Rema , Brown Leon D , Inman Douglas , Simons Stefaan J. R. , Shearing Paul R , Brett Dan J. L.
Published: April 2014

The electrochemical reduction of metal oxides is important in the production of refractory metals. The conventional electroreduction routes have low efficiencies and limitations associated with oxide scaling on the surfaces of solid precursors, as well as issues related to effective electrolyte access. The ‘fluidised cathode’ process offers a promising substitute route to the direct electrochemical reduction. The process is demonstrated on a tungsten and LiCl-KCl model system. Cyclicvoltammetry was used to characterise the reduction electrochemistry and chronoamperometry showed the evolution of the electrodeposition process with time. The product samples were analysed using SEM and EDS. Preliminary particle coulometry measurements were also performed.
Nanoscale Electrochemical Processes On Cu(111) Surface Using Periodic DFT and Quantum/Classical Simulations
Authors: Sumer Aslihan , Losada Martin , Chaudhuri Santanu
Published: April 2014

In this work, we explored the energetic and configurational properties of molecular oxygen adsorption on Cu(111) in water using classical mechanics and electronic structure based computations. It has been found that the structure of the water network surrounding the oxygen at the electrolyte/metal interface can be determinant in the adsorption configuration of the molecule on the metal surface, instead of the energetic ordering of possible adsorption configurations. An external electric field applied to the H2O/Cu(111) models to simulate the electrode potentials of electrochemical nature of the system are shown to affect the orientations of water molecules, thus affect the configuration, energetics and rate of oxygen adsorption on Cu(111).
Electrocatalytic Oxygen Reduction and Water-Oxidation on Transition Metal Ion-Doped MnO2, RuO2 and IrO2 in Alkaline Aqueous Solutions
Authors: Jeevagan Arcokiam John , Suzuki Yukiko , Gunji Takao , Saravanan Govindachetty , Irii Yuta , Tsuda Takashi , Onobuchi Toshiaki , Kaneko Shingo , Kobayashi Genki , Matsumoto Futoshi
Published: April 2014

We have synthesized metal oxides (MnO2, RuO2, IrO2, and transition metal (Ru, Ir and Ni) ion-doped metal oxides) using a precipitation method and exhaustively examined their bifunctional electrocatalytic activities for the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) in alkaline solutions. X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) measurements were used to study the structure and electronic states of the catalysts. The XRD and XPS data confirmed the successive modification of the structure and electronic states on the catalyst surface by doping transition metal ions into MnO2, RuO2 and IrO2. The samples showed stable performance in terms of their overpotential. The MnO2-based metal oxide exhibited a relatively lower overpotential for ORR. Mn1-nRunOx, Ru1-nNinOx, and Ru1-nIrnOx were identified as preferable catalysts for OER. From the samples examined in this study, Mn1-nRunOx (n = 0.1, 0.2, 0.8) and Ru0.9Ni0.1Ox showed promise as bifunctional catalysts.
Direct Electrochemical Reduction of Hematite Pellets in Alkaline Solutions
Authors: Haarberg Geir Martin , Yuan Boyan
Published: April 2014

Our previous studies on the electrowinning of iron from hematite particles suspended in sodium hydroxide solutions demonstrated that iron was produced through a direct solid phase electrochemical reduction of the oxide particles. This suggests that the electro-deoxidation of a hematite powder pellet by the FFC type process should be possible in aqueous solutions at a low temperature. We investigated the electrochemical reduction of a solid hematite pellet cathode manufactured by conventional mechanical pressing followed by sintering process in concentrated sodium hydroxide solutions using a nickel inert anode at 110 °C. The experimental results indicated that hematite was reduced to iron metal. Propagation of the reduction reaction front through the oxide phase occurred at a high speed, and the rate-determining step was the diffusion of the oxygen ion through the shrinking cores of the oxide particle.
Tin Oxide and Nickel Ferrite Anodic Behavior in Molten Chlorides
Authors: Haarberg Geir Martin , Kvalheim Eirin , Martinéz Ana Maria
Published: April 2014

Inert oxygen evolving anodes are much desired to replace carbon anodes in proposed electrolysis processes in molten salt electrolytes containing dissolved oxides. Experiments were performed in molten CaCl2-NaCl-CaO at 650 oC and KCl-LiCl-LiO2 at 450 - 550 oC. The behaviour of nickel ferrite and tin oxide based anodes was studied by long time electrolysis. Voltammetry was used to study the electrochemical behaviour of dissolved oxide complexes.
Evaluation of MEAs Prepared by Pt/C Electrocatalysts with Improved Durability through the Heat Treatment
Authors: Zhao Xiaojing , Hayashi Akari , Noda Zhiyun , Sasaki Kazunari
Published: April 2014

With the aim of developing durable electrocatalysts for polymer electrolyte fuel cells, their durability with different carbon supports have been evaluated electrochemically in our study. During our previous investigation, we have found that graphitization of carbon surface through the heat treatment at appropriate temperature is a simple but useful technique to improve the durability of electrocatalysts. Especially, a catalyst made by heat treatment of Vulcan carbon at 1600 oC, Pt/GVC1600, has shown much more improved durability than one made without heat treatment, Pt/VC, in the half-cell evaluation. In this study, MEA with Pt/GVC1600 for the cathode was developed and evaluated. Initial performance of MEA was found to be almost the same between these two catalysts, but regarding to durability, Pt/GVC1600 showed much more improved durability than Pt/VC. Heat treatment of carbon supports at optimum temperature lead to increasing in durability not only in the half-cell but also in the full-cell.
Semiconducting Ta3N5-Polymer Nanohybrid that Photoelectrolyze Water
Authors: Skorupska Katarzyna , Giordano Cristina , Zoladek Sylwia , Zurowski Artur , Milke Betna , Gao Qingsheng S. , Ramirez-Caro Alejandra , Fiechter Sebastian , Lewerenz H. Joachim , Kulesza Pawel J.
Published: April 2014

The successful preparation of a nanohybrid electrode made from Ta3N5 nanoparticle powders interlinked by Nafion is described. The basic photoelectrochemical properties as anode for water photolysis are investigated and gas evolution as well as corrosion reactions are determined by differential electrochemical mass spectroscopy (DEMS) and X-ray photoelectron spectroscopy (XPS). The sample shows oxygen evolution but also photocorrosion, oxidation of the Ta3N5 nanoparticles via the O 1s line in XPS experiment. The photocorrosion reaction results in a core-shell structure consisting of a tantalum oxide shell and a tantalum nitride core as seen in XPS and x-ray diffraction.
(Invited) Enhancement of Photoelectrochemical Water Splitting and Solar Energy Induced Electroreduction of Carbon Dioxide through Utilization of Plasmonic and Electrocatalytic Metal Nanoparticles
Authors: Zoladek Sylwia , Solarska Renata , Skorupska Katarzyna , Rutkowska Iwona Agnieszka , Wadas Anna , Bienkowski Krzysztof , Lewerenz Joachim H. , Palys Barbara , Kulesza Pawel J.
Published: April 2014

In the present study, we utilize phosphomolybdate (PMo12O40
3-) modified gold nanoparticle (diameters, 30-40 nm) deposits on mesoporous tungsten oxide photoanodes to study plasmon-assisted photoelectrochemical water splitting. Such n-type semiconducting oxide as WO3 (band gap, 2.5 eV) suffers from inadequate solar light absorption and, therefore, there is a need to use of a thin plasmon active layer of nanostructured Au of proper architecture to enhance the interfacial light trapping and conversion. A remarkable increase in the solar energy conversion efficiency as well as in the photooxidation current (oxygen evolution) are believed to be induced by the plasmonic excitation of Au nanoparticles occurring within WO3 absorption range. The polyoxometallate (PMo12O40
3-) monolayer-type nanostructures may play electrocatalytic role, improve charge distribution, in addition to the stabilization effect. In the other study, the PMo12O40
3- modified Au nanoparticles, when deposited on step-bunched silicon Si(111) surface have also acted as electrocatalytic centers during photoelectrochemically induced reduction of carbon oxide (IV). The applicability of phosphomolybdate-protected gold nanoparticles to create porous matrix for photoelectrochemically assisted reduction of carbon dioxide is even more pronounced when the system is further decorated with copper. We also present the result of decorating multi-walled carbon nanotubes with gold and copper nanoparticles (by chemical reduction method and through electrodeposition) acting as catalytic systems active towards CO2 electroreduction under voltammetric conditions. Carbon nanotubes have been chemically modified here with surface oxygen complexes using HNO3 and H3PMo12O40 solutions.
Solar Water Splitting By Transition Metal Oxide – Silicon Photoanodes Prepared under Cathodic Electrochemical Conditions
Authors: Lublow Michael , Schedel-Niedrig Thomas , Fischer Anna
Published: April 2014

Photo-assisted water splitting represents a pivotal strategy for realization of the hydrogen economy of the future. In this approach, the preparation of stable and efficient photoanodes is challenging due to the susceptibility of sensitive semiconductors to photocorrosion. Here, we demonstrate a metalorganic electrochemical approach by which amorphous transition metal oxides are formed on silicon under cathodic electrochemical conditions. This approach makes anti-corrosive interlayers potentially superfluous and realizes an oxide-silicon heterostructure with enhanced activity for the light-induced oxygen evolution reaction in alkaline electrolytes. Exemplifying analysis of electronic and optical properties is provided for a nickel oxide / silicon heterojunction. Interface engineering is demonstrated by formation of nanoscopic Au-Si heterocontacts acting as rectifying nanoemitters for light-induced holes toward the electrocatalytic nickel oxide layer.
Titanium Oxide Electrodeposition on Diamond/Ti Electrodes with Different Boron Dopings
Authors: Couto Andrea Boldarini , Migliorini Fernanda Lanzoni , Baldan Mauricio Ribeiro , Ferreira Neidenei Gomes
Published: April 2014

The eletrodeposition of titanium oxide on semiconducting boron doped diamond grown on Ti substrate was investigated. Emphasis is given in the study of the influence of the doping level on BDD in the anodic hydrolysis of TiCl3 for obtaining TiO2/BDD composites. The BDD films as-grown were characterized by Raman Spectroscopy and the acceptor concentrations were evaluated around 1019 and 1021 boron atoms cm-3 for the electrode E1 and the electrode E2, respectively. Scanning electron microscopy showed that the deposits resulted in morphology composed of small grains distributed throughout the BDD surface for both electrodes. The influence of doping level showed that for E2 electrode, the deposits presented higher density with clusters at the grain faces and best uniformity of TiO2 on its surface than that for E1 electrode. This behavior may be associated to the better conductivity of the electrode E2 due to its higher boron content enhancing the titanium oxidation reaction. According the X-ray diffraction data, the rutile TiO2 crystallographic form was obtained for all the depositions.
Durability and Activity of Modified Nickel Anode for Alkaline Water Electrolysis
Authors: Ichikawa Hiroki , Matsuzawa Koichi , Kohno Yuji , Nagashima Ikuo , Sunada Yoshio , Nishiki Yoshinori , Manabe Akiyoshi , Mitsushima Shigenori
Published: April 2014

Alkaline water electrolysis (AWE) produces highly pure hydrogen with simple and less expensive configuration. Conventional anode is Ni based material, and it is stable in steady electrolysis; however it deteriorates in some cases with the fluctuation of electric power supply, for example where renewable energy such as wind or solar power. To improve durability under potential fluctuation, we have investigated the catalytic activity and durability of oxygen evolution reaction (OER) for three types of Ni based electrodes with and without pre-oxidation under potential cycling. Surface oxidized nickel anode was more stable than nickel anode, but it is less active than nickel in high current density region because of electronic resistance of surface oxide. Lithium doped surface oxide improved electronic conductivity, and it had the better activity and durability than those of both nickel and surface oxidized nickel.
Electrophoretic Deposition of Cobalt Ferrite and Platinum Cobalt Nanoparticles as Electrocatalysts
Authors: Tanakit Ryan , Luc Wesley , Talbot J. B.
Published: April 2014

Cobalt ferrite and platinum cobalt nanoparticles were deposited using electrophoretic deposition (EPD) from two different bath chemistries. The first bath contained 2 g/L particles suspended in 90 vol.% water and 10 vol.% isopropanol with 0.4 g/L hexadecyltrimethlyammonium bromide. The second bath contained 2 g/L particles suspended in 100 % ethanol. The deposits were tested for electrocatalytic properties for the oxidation of ammonium sulfite to ammonium sulfate. Linear sweep voltammetry showed that both EPD deposits of cobalt ferrite and platinum cobalt nanoparticles had electrocatalytic activity.
Electrophoretic Deposition of Quantum Dots for Photovoltaic Applications
Authors: Lee Seung Whan , Hlaing Htay , Kymissis Ioannis , Herman Irving P.
Published: April 2014

The electrophoretic deposition (EPD) of quantum dots (QDs) after ligand exchange is investigated, along with its use as one step in the formation of photovoltaic (PV) device structures. The ligands on CdSe QDs are exchanged to pyridine and these QDs are deposited by EPD in heterojunction PV structures, which are then tested.
Deposition of Vulcan XC-72 Coatings on Stainless Steel Bipolar Plates by Reverse Pulsed DC Voltage Electrophoretic Deposition (EPD) for Fuel Cell Applications
Authors: Pech-Rodríguez W. J. , González-Quijano D. , Vargas-Gutiérrez G. , Rodríguez-Varela F. J.
Published: April 2014

In this study, surface coatings of a mixture of Vulcan XC-72 and Polypyrrole (PPy), labeled as PPy-C, were deposited on stainless steel (SS) substrates by EPD under reverse pulsed DC voltage in order to study the corrosion protection. The Effect of applied voltages (50, 70, 90 and 120 V) and deposition time (2, 6, 10 and 15 min) on the film characteristics was evaluated. The coatings were analyzed by SEM, and the result showed that the amount of PPy electrodeposited and the morphology of the film depended on the conditions of deposition. Polarization curves were conducted in order to evaluate the corrosion resistance of the bipolar plates in 0.1 M H2SO4 at room temperature. The experimental results indicated that the PPy-C composites increased the corrosion potential of the SS and decreased the corrosion current density by one order of magnitude. The structure properties of the coatings were characterized by Fourier Transform Infrared Spectroscopy (FTIR), and the spectra shows the presence of characteristics absorption bands of PPy. These results indicated that EPD is a suitable technique to deposit polymer/carbon corrosion protection films for applications in fuel cell bipolar plates.
Wide pH Range Electroless Copper Deposition at Room Temperature EQCM and CV Study of Autocatalytic Copper(II) Reduction by Cobalt(II)-Pentaethylenehexamine Complexes
Authors: Norkus Eugenijus , Stankevičienė Ina , Tamašauskaitė-Tamašiūnaitė Loreta , Stalnionis Giedrius , Prušinskas Kestutis , Jagminienė Aldona
Published: April 2014

Co(II) complex with pentaethylenehexamine was found to be an effective reducing agent in the autocatalytic reduction of Cu(II) to metal (electroless copper plating). Cyclic voltammetry and electrochemical quartz crystal microgravimetry were used to study the autocatalytic Cu(II) reduction by Co(II) in pentaethylenehexamine solutions. Electroless copper plating was studied by measuring the instantaneous copper deposition rate, open-circuit potential and electrochemical parameters of the partial reactions. It was determined that the electrochemically active and easily oxidizable Co(II) complexes with pentaethylenehexamine are formed in a wide solution pH range, from acidic (pH 4.4) to alkaline (pH 9.5) medium. The maximum copper deposition rate at 20 oC was obtained at pH about 5 and is equal to 55.1 µg cm-2/2 min.
Electroless Co-B-P-W Deposition Using DMAB as Reducing Agent
Authors: Norkus Eugenijus , Jagminienė Aldona , Stankevičienė Ina , Tamašauskaitė-Tamašiūnaitė Loreta , Sukackienė Zita
Published: April 2014

Co-B-P-W alloy films were deposited by the electroless plating method on Cu foil and on Si wafer with a sputtered PVD TaN/Ta barrier and Cu seed substrate. The effects of concentration of the reactants and temperature on the deposition rate were investigated. By variation of electroless plating solution composition, Co-B-P-W coatings containing different amounts of boron, phosphorus and tungsten can be obtained under slightly acid conditions. Using operating conditions selected Co-B-P-W coatings containing 0.5-10.0 at. % W, 0.5-16.0 at. % B and 1.5-6.0 at. % P can be obtained. The induction period depends on solution composition, but can be effectively shortened by elevation of the temperature of working solution.
Formation of Titanium Dioxide Nanotube Arrays by Anodizing Ti6Al4V Alloy
Authors: Bölükoğlu Zeynep , Karakaya Ishak , Erdoğan Metehan
Published: April 2014

Titanium dioxide thin films of nanoporous structures have gained great interest due to their large surface area and high reactivity properties in their applications. One of the methods used to form titanium dioxide nanostructures is anodizing the surface of titanium in F- ion containing electrolytes. Effects of HF concentration (0.1 to 0.5 wt.%), anodizing potential (10 to 30 V) and time (30 to 180 minutes) on the titanium dioxide nanotube formation were investigated by anodically oxidizing Ti6Al4V alloy in this study. Scanning electron microscopy (SEM) images were used to determine the influences of different experimental conditions. In addition, photovoltaic effects from a well-defined cell were used to infer comparative information on the total surface area of nanotubes.
Pantoprazole decreases gastroesophageal muscle tone in newborn rats via rho-kinase inhibition
Authors: Welsh Christopher , Kasirer Moshe Yair , Pan Jingyi , Shifrin Yulia , Belik Jaques
Published: April 2014

Proton pump inhibitors reduce gastric acid secretion and are commonly utilized in the management of gastroesophageal reflux disease across all ages. Yet a decrease in lower esophageal sphincter tone has been reported in vitro in rats through an unknown mechanism; however, their effect on the gastroesophageal muscle tone early in life was never studied. Hypothesizing that proton pump inhibitors also reduce gastroesophageal muscle contraction in newborn and juvenile rats, we evaluated the in vitro effect of pantoprazole on gastric and lower esophageal sphincter muscle tissue. Electrical field stimulation and carbachol-induced force were significantly ( P < 0.01) reduced in the presence of pantoprazole, whereas the drug had no effect on the neuromuscular-dependent relaxation. When administered in vivo, pantoprazole (9 mg/kg) significantly ( P < 0.01) reduced gastric emptying time at both ages. To ascertain the signal transduction pathway responsible for the reduction in muscle contraction, we evaluated the tissue ROCK-2 and CPI-17 activity. Pantoprazole reduced myosin light chain phosphatase MYPT-1, but not CPI-17 phosphorylation of gastric and lower esophageal sphincter tissue, strongly suggesting that it is a ROCK-2 inhibitor. To the extent that these findings can be extrapolated to human neonates, the use of pantoprazole may impair gastric and lower sphincter muscle tone and thus paradoxically exacerbate esophageal reflux. Further studies addressing the effect of proton pump inhibitors on gastroesophageal muscle contraction are warranted to justify its therapeutic use in gastroesophageal reflux disease.
Fibroblast growth factor 15 deficiency impairs liver regeneration in mice
Authors: Kong Bo , Huang Jiansheng , Zhu Yan , Li Guodong , Williams Jessica , Shen Steven , Aleksunes Lauren M. , Richardson Jason R. , Apte Udayan , Rudnick David A. , Guo Grace L.
Published: April 2014

Fibroblast growth factor (FGF) 15 (human homolog, FGF19) is an endocrine FGF highly expressed in the small intestine of mice. Emerging evidence suggests that FGF15 is critical for regulating hepatic functions; however, the role of FGF15 in liver regeneration is unclear. This study assessed whether liver regeneration is altered in FGF15 knockout (KO) mice following 2/3 partial hepatectomy (PHx). The results showed that FGF15 KO mice had marked mortality, with the survival rate influenced by genetic background. Compared with wild-type mice, the KO mice displayed extensive liver necrosis and marked elevation of serum bile acids and bilirubin. Furthermore, hepatocyte proliferation was reduced in the KO mice because of impaired cell cycle progression. After PHx, the KO mice had weaker activation of signaling pathways that are important for liver regeneration, including signal transducer and activator of transcription 3, nuclear factor-κB, and mitogen-activated protein kinase. Examination of the KO mice at early time points after PHx revealed a reduced and/or delayed induction of immediate-early response genes, including growth-control transcription factors that are critical for liver regeneration. In conclusion, the results suggest that FGF15 deficiency severely impairs liver regeneration in mice after PHx. The underlying mechanism is likely the result of disrupted bile acid homeostasis and impaired priming of hepatocyte proliferation.
Glutamate formation via the leucine-to-glutamate pathway of rat pancreas
Authors: Schachter David , Buteau Jean
Published: April 2014

The leucine-to-glutamate (Leu→Glu) pathway, which metabolizes the carbon atoms of l-leucine to form l-glutamate, was studied by incubation of rat tissue segments with l-[U-14C]leucine and estimation of the [14C]glutamate formed. Metabolism of the leucine carbon chain occurs in most rat tissues, but maximal activity of the Leu→Glu pathway for glutamate formation is limited to the thoracic aorta and pancreas. In rat aorta, the Leu→Glu pathway functions to relax the underlying smooth muscle; its functions in the pancreas are unknown. This report characterizes the Leu→Glu pathway of rat pancreas and develops methods to examine its functions. Pancreatic segments effect net formation of glutamate on incubation with l-leucine, l-glutamine, or a mix of 18 other plasma amino acids at their concentrations in normal rat plasma. Glutamate formed from leucine remains mainly in the tissue, whereas that from glutamine enters the medium. The pancreatic Leu→Glu pathway uses the leucine carbons for net glutamate formation; the α-amino group is not used; the stoichiometry is as follows: 1 mol of leucine yields 2 mol of glutamate (2 leucine carbons per glutamate) plus 2 mol of CO2. Comparison of the Leu→Glu pathway in preparations of whole pancreatic segments, isolated acini, and islets of Langerhans localizes it in the acini; relatively high activity is found in cultures of the AR42J cell line and very little in the INS-1 832/13 cell line. Pancreatic tissue glutamate concentration is homeostatically regulated in the range of ∼1–3 μmol/g wet wt. l-Valine and leucine ethyl, benzyl, and tert-butyl esters inhibit the Leu→Glu pathway without decreasing tissue total glutamate.
Substance P is essential for maintaining gut muscle contractility: a novel role for coneurotransmission revealed by botulinum toxin
Authors: Li Cuiping , Micci Maria-Adelaide , Murthy Karnam S. , Pasricha Pankaj Jay
Published: April 2014

Substance P (SP) is commonly coexpressed with ACh in enteric motor neurons, and, according to the classical paradigm, both these neurotransmitters excite smooth muscle via parallel pathways. We hypothesized that, in addition, SP was responsible for maintaining the muscular responsiveness to ACh. We tested this hypothesis by using botulinum toxin (BoNT/A), a known blocker of vesicular release of neurotransmitters including ACh and neuropeptides. BoNT/A was injected into rat pyloric sphincter in different doses; as control we used boiled BoNT/A. At the desired time point, pylorus was dissected out and pyloric contractility was measured ex vivo in an organ bath and by measuring phosphorylation of myosin light chain 20 (MLC20). BoNT/A (10 IU) significantly reduced the response of pyloric muscle to exogenous ACh, an effect that was accompanied by reduced MLC20 phosphorylation in the muscle. Both effects were reversed by exogenous SP. CP-96345, a NK1 receptor antagonist, blocked the ability of exogenous SP to reverse the cholinergic hyporesponsiveness as well as the reduction in MLC20 phosphorylation induced by BoNT/A. In conclusion, we have identified a novel role for SP as a coneurotransmitter that appears to be important for the maintenance of muscular responsiveness to the principal excitatory neurotransmitter, ACh. These results also provide new insight into the effects of botulinum toxin on the enteric nervous system and gastrointestinal smooth muscle.
Small heat shock proteins translocate to the cytoskeleton in human skeletal muscle following eccentric exercise independently of phosphorylation
Authors: Frankenberg Noni T. , Lamb Graham D. , Overgaard Kristian , Murphy Robyn M. , Vissing Kristian
Published: April 2014

Small heat shock proteins (sHSPs) are a subgroup of the highly conserved family of HSPs that are stress inducible and confer resistance to cellular stress and injury. This study aimed to quantitatively examine whether type of contraction (concentric or eccentric) affects sHSPs, HSP27 and αB-crystallin, localization, and phosphorylation in human muscle. Vastus lateralis muscle biopsies from 11 healthy male volunteers were obtained pre- and 3 h, 24 h, and 7 days following concentric (CONC), eccentric (ECC1), and repeated bout eccentric (ECC2) exercise. No changes were apparent in a control group ( n = 5) who performed no exercise. Eccentric exercise induced muscle damage, as evidenced by increased muscle force loss, perceived muscle soreness, and elevated plasma creatine kinase and myoglobin levels. Total HSP27 and αB-crystallin amounts did not change following any type of exercise. Following eccentric exercise (ECC1 and ECC2) phosphorylation of HSP27 at serine 15 (pHSP27-Ser15) was increased approximately 3- to 6-fold at 3 h, and pαB-crystallin-Ser59 increased ∼10-fold at 3 h. Prior to exercise most of the sHSP and psHSP pools were present in the cytosolic compartment. Eccentric exercise resulted in partial redistribution of HSP27 (∼23%) from the cytosol to the cytoskeletal fraction (∼28% for pHSP27-Ser15 and ∼7% for pHSP27-Ser82), with subsequent full reversal within 24 h. αB-crystallin also showed partial redistribution from the cytosolic to cytoskeletal fraction (∼18% of total) 3 h post-ECC1, but not after ECC2. There was no redistribution or phosphorylation of sHSPs with CONC. Eccentric exercise results in increased sHSP phosphorylation and translocation to the cytoskeletal fraction, but the sHSP translocation is not dependent on their phosphorylation.
Soy-dairy protein blend and whey protein ingestion after resistance exercise increases amino acid transport and transporter expression in human skeletal muscle
Authors: Reidy P. T. , Walker D. K. , Dickinson J. M. , Gundermann D. M. , Drummond M. J. , Timmerman K. L. , Cope M. B. , Mukherjea R. , Jennings K. , Volpi E. , Rasmussen B. B.
Published: April 2014

Increasing amino acid availability (via infusion or ingestion) at rest or postexercise enhances amino acid transport into human skeletal muscle. It is unknown whether alterations in amino acid availability, from ingesting different dietary proteins, can enhance amino acid transport rates and amino acid transporter (AAT) mRNA expression. We hypothesized that the prolonged hyperaminoacidemia from ingesting a blend of proteins with different digestion rates postexercise would enhance amino acid transport into muscle and AAT expression compared with the ingestion of a rapidly digested protein. In a double-blind, randomized clinical trial, we studied 16 young adults at rest and after acute resistance exercise coupled with postexercise (1 h) ingestion of either a (soy-dairy) protein blend or whey protein. Phenylalanine net balance and transport rate into skeletal muscle were measured using stable isotopic methods in combination with femoral arteriovenous blood sampling and muscle biopsies obtained at rest and 3 and 5 h postexercise. Phenylalanine transport into muscle and mRNA expression of select AATs [system L amino acid transporter 1/solute-linked carrier (SLC) 7A5, CD98/SLC3A2, system A amino acid transporter 2/SLC38A2, proton-assisted amino acid transporter 1/SLC36A1, cationic amino acid transporter 1/SLC7A1] increased to a similar extent in both groups ( P < 0.05). However, the ingestion of the protein blend resulted in a prolonged and positive net phenylalanine balance during postexercise recovery compared with whey protein ( P < 0.05). Postexercise myofibrillar protein synthesis increased similarly between groups. We conclude that, while both protein sources enhanced postexercise AAT expression, transport into muscle, and myofibrillar protein synthesis, postexercise ingestion of a protein blend results in a slightly prolonged net amino acid balance across the leg compared with whey protein.