bluuebunny/crossref_metadata_2025 huggingface dataset:
Substitution Effect for Br on the Lithium Ion Conductivity of Lithium Indium Bromide
Authors: Tomita Yasumasa , Nishiyama Hiroo , Kobayashi Kenkichiro , Kohno Yoshiumi , Maeda Yasuhisa , Yamada Koji
Published: March 2009

Li3InBr6-yXy (X=F, I) was synthesized and the substitution effect on ionic conductivity was investigated. Li3InBr6-yFy was single phase at y {less than or equal to} 3. The lattice constants were decreased with F content. The conductivity of Li3InBr6-yFy was decreased with y and electrochemical stability was improved by the substitution. The conductivity in Li3InBr6-yIy(y {less than or equal to} 3) was changed with y and Li3InBr3I3 showed the highest value in these compounds to be 3 ×10-3 Scm-1 at 333 K. 7Li NMR spectra in Li3InBr6-yIy was sharp and it was confirmed the diffusion of Li ion was fast at room temperature.
Li-ion Rechargeable Batteries Based on LiFePO4: A comparative Study on the Nanostructured Composite Positive Electrode With Two Different Carbon Coating
Authors: Kumar Arun , Thomas Reji , Karan Naba K. , Tomar Maharaj S. , Katiyar Ram S.
Published: March 2009

Nanostructured Carbon-LiFePO4 composite cathode materials were prepared with conventional solid-state route. The orthorhombic olivine structure without any impurity was obtained at 650{degree sign}C. The average LiFePO4 particle sizes were ~80 nm and were coated with residual carbon. The cyclic voltammograms showed only a pair of peaks corresponding to the anodic and cathodic reactions. The irreversible capacity loss in the first cycle was 5 mAh/gm, and the Coulombic efficiency was 97%. The first discharge capacity was 157 mAh/g, equivalent to 93% of the theoretical capacity (Fe2+/Fe3+ redox efficiency). Capacity retention after 80 cycles was ~98% and hence insignificant capacity fading.
Ammonia-treated Titania as an Anode Material of Lithium-ion Battery with High-rate Capability
Authors: Tanaike Osamu , Kiyono Hajime , Shimada Shiro , Toyoda Masahiro , Tsumura Tomoki
Published: March 2009

Titania nanofiber was attempted to be partly nitrided by direct heat-treatment in ammonia gas flow at 800~1000{degree sign}C, in order to add the high electron conductive property of titanium nitride into titania to make titanium compounds having both lithium insertion ability and high electron conductivity in one particle. The resulted compounds from the fiber showed a good rate-capability of reversible lithium insertion even without any addition of conductive-support material, such as carbon black.
Interpenetrating Networks Based on Poly(trimethylene Carbonate) and Poly(ethylene oxide) Blends Doped With Lithium Salts
Authors: Barbosa Paula , Rodrigues Luísa , Silva Manuela , Smith Michael
Published: March 2009

Solid polymer electrolytes based on poly(trimethylene carbonate) and poly(ethylene oxide) interpenetrating networks doped with lithium hexafluoroantimonate have been prepared and characterized by measurements of ionic conductivity, cyclic voltammetry, differential scanning calorimetry and thermogravimetry. Electrolytes with lithium salt compositions of n between 5 and 15 (where n represents the total number of cation-coordinating units per lithium ion) and a host polymer component of -(O=COCH2CH2CH2O)n- units contributing between 5 and 15 wt% of the electrolyte formulation, were prepared by co-dissolution in acetonitrile. The solvent casting technique was used to produce flexible, transparent and free-standing films.
Carbon-vanadium Nitride Composite for Electrode with High-rate Capability
Authors: Tsumura Tomoki , Kiyo Tateki , Toyoda Masahiro , Tanaike Osamu
Published: March 2009

Carbon vanadium nitride composite was prepared as an active material in lithium ion battery with high-rate capability through carbothermal reduction of fibrous NH4+ intercalated vanadium xerogel at above 1000 oC under nitrogen gas flow. Carbon-vanadium nitride composite prepared showed reversible electrochemical lithium insertion/extraction in 1M LiBF4 EC/DEC electrolyte, discharge capacity down to 0 V being 240, 180, and 125 mAh g-1 at current density of 50, 100, and 1000 mA g-1 respectively.
The Change of the Lithium-Sulfur Cell Components Properties by its Cycling
Authors: Kolostnitsyn Vladimir , Kuzmina Elena , Karaseva Elena Vladimirovna , Mochalov Sergey Ernstovich
Published: March 2009

The changes to properties of lithium-sulphur cell components (electrolyte, sulphur and lithium electrodes) during cycling were studied by AC impedance spectroscopy. It was found that the changes to properties of these components vary depending on the state of charge. We believe that observed changes can be explained by formation of soluble lithium polysulfides and by the change of their concentration and composition during the cell cycling.
Polyethylene Oxide-Based Gel Membrane Electrolytes for Lithium Batteries
Authors: Luo Kan , Filler Robert , Mandal Braja K.
Published: March 2009

A new gel polymer electrolyte has been prepared by entrapping a sufficient amount of non-aqueous lithium salt solution into a cross-linked polyethylene oxide (PEO) matrix. The morphology of this electrolyte was studied by both DSC and scanning electron microscopy, which revealed no crystallinity from -100o to 120oC and nearly a pore-free surface. Cyclic voltammetry was performed to obtain the electrochemical stability of the gel electrolytes, while an ionic conductivity of 1.826×10-3 S/cm was observed by complex impedance measurement. The flexible and strong texture of the matrix showed acceptable mechanical properties suitable for fabrication of secondary lithium-ion batteries.
Electrochemical Properties of Helical Carbon Nanomaterials Formed on LiCoO2 by CVD Method
Authors: Uno Yusuke , Tsujikawa Tomonobu , Hirai Toshiro
Published: March 2009

We used chemical vapor deposition (CVD) to fabricate helical carbon nanomaterials (HCNs) on the surface of LiCoO2 particles and estimated their electrochemical properties. Through SEM measurements, we observed mainly four morphological types of HCNs. It was found that the electrochemical properties of cells with the HCNs were not as good as those of cells with acetylene black (AB).
Influence of Cathode Active Materials Obtained by a Wet-type Jet Mill on Lithium Cell Performance
Authors: Hirai Toshiro , Takahata Jun-ichi , Tsujikawa Tomonobu
Published: March 2009

We prepared slurries by dispersing LiMn2O4 and LiCoO2 into toluene or NaPO3 aqueous solution. The slurries were then milled with a high-pressure wet-type jet mill to form fine particles. In estimating the performance of Li cells containing the materials, we found that the cell capacity improved with a decrease in the materials' particle size. Maximum cell capacity was obtained using materials produced by milling NaPO3 slurry to reduce the particle diameter to 2-3 μm. We also found that the cell cycle life tended to increase with a decrease in the mean diameter of the material particles.
Fabrication of Size-controllable Flower-like TiO2 and its Photocatalytic Activity
Authors: Jitputti Jaturong , Pavasupree Sorapong , Suzuki Yoshikazu , Yoshikawa Susumu
Published: March 2009

Size-controllable flower-like titante superstructure was prepared by simple hydrothermal method from amorphous TiO2 sphere precursor without any template. By changing concentration of electrolyte (KCl), the size of amorphous TiO2 sphere precursor could be controlled. N2-sorption analysis, scanning electron microscopy (SEM), and X-ray diffraction (XRD) observation of as-prepared samples revealed the formation of titanate nanosheet structure with high surface area of 350.7 m2g-1. Upon thermal treatment at 500 oC, the titanate nanosheets were converted into anatase TiO2 with deformation of their structures. The as-prepared flower-like titanate showed high photocatalytic activity for H2 evolution from water splitting reaction. Moreover, the sample heat treated at 500 oC exhibit higher photocatalytic activity than that of commercial TiO2 anatase powder (ST-01).
Hybrid Bulk Heterojunction Solar Cells with Anatase Titanium Dioxide Nanotube Arrays from Liquid Phase Deposition by Using ZnO Template
Authors: Rattanavoravipa Thitima , Sagawa Takashi , Yoshikawa Susumu
Published: March 2009

We demonstrated preparation of vertically nanotube arrays of TiO2 through the liquid phase deposition method by using ZnO template and application of such arrays as electrode for hybrid solar cell. XRD, EDX and SEM measurements enabled to confirm the successful formation of the TiO2 nanotube arrays. Hybrid solar cells based on TiO2 nanotube arrays spin-coated with the mixture of P3HT and PCBM were fabricated. Surface modification of the TiO2 with N719 dye remarkably enhanced the conversion efficiencies of the solar cells owning to better interfacial contact between the active layer of the polymers and the electrode of TiO2 nanotube surface.
Silicon Nanostructures or Photocatalytic and Photovoltaic Application by Chronoamperometric Conditioning
Authors: Lublow Michael , Lewerenz Hans J.
Published: March 2009

Silicon nanostructures on Si(111) substrates were prepared by photoelectrochemical dissolution in diluted ammonium fluoride containing solutions and under optical real-time control by Brewster-angle reflectometry. Subsequent Pt-electrodepostion resulted in formation of local Schottky-barriers and surface passivation by an ultra-thin SiO2 film. Efficiencies of the monolithic system for photoelectrochemical solar energy conversion and for photoelectrocatalytic evolution of hydrogen were investigated in dependence of the preceding surface preparation. Smooth nanotopographies on n-type Si(111), consisting of recurrent structures with 2nm average height, showed highest device performance while an increasing aspect ratio of the structures reduced the efficiency. As possible cause, lower densities of Pt-contacts on stronger corrugated surfaces were observed. Comparable results were obtained for p-type Si(111) in corresponding experiments for hydrogen reduction.
Energy-Storable Dye-Sensitized Solar Cells with Tungsten Oxide Charge-Storage Electrode
Authors: Saito Yosuke , Uchida Satoshi , Kubo Takaya , Segawa Hiroshi
Published: March 2009

A photo-electrochemical rechargeable solar cell with an inorganic charge-storage material as a third electrode was investigated. The energy-storable function was based on the redox reactions in dye-sensitized solar cells and the charge-storage electrode. In this study, tungsten oxide was used as the charge-storage material. Depending on the structure and morphology of the tungsten oxide, the charge-storage properties were improved.
Formation of Self Ordered TiO2 Nanotubes by Electrochemical Anodization of Titanium in 2-Propanol / NH4F
Authors: Bayoumi Hassan Fathy M. , Nanjo Hiroshi , Tetsuka Hiroyuki , Kanakubo Mitsuhiro , Aizawa Takafumi , Nishioka Masateru , Ebina Takeo
Published: March 2009

In the present work we report that TiO2 nanotubes (TiNT) can be formed by electrochemical anodization of titanium in an 2-propanol/water + 0.14 M NH4F. The effects of water contents, time of anodization and the potential on the growth behavior of the TiNT were studied. The optimum solvent composition water / 2-propanol was found 16 vol% water. At this % the reaction between solvated electrons and hydrogen ions, which was considered as a possible rate determine step, is kinetically controlled. The titania nanotubes obtained under the optimum conditions have heights up to 1800 nm and inner diameters around 90 nm. Increasing the potential beyond 20 V did not show better nanotubes. This was attributed to the fast reactions under the high field led to disordering equilibrium of the controlling reactions.
Physical and Photocatalytic Properties of TiO2 Nanostructures Fabricated by Means of Glancing Angle Deposition
Authors: Pihosh Yuriy , Turkevych Ivan , Ye Jinhua , Goto Masahiro , Kasahara Akira , Tosa Masahiro
Published: March 2009

Structural, optical and photocatalytic properties of various TiO2 nanostructures prepared by glancing angle deposition (GLAD) and by electrochemical anodic oxidation of Ti were studied. The TiO2 nanorods were prepared on unheated glass substrates by reactive sputtering of Ti in a mixture of Ar and O2 gases in a glancing angle deposition (GLAD) regime. The crystal structure of the TiO2 nanorods was characterized by X-ray diffraction (XRD) and the obtained spectra showed that both anatase and rutile phases are present in the GLAD deposited nanorods with the ratio which corresponds to the ratio of Ar and O2 in the working gas. In addition, TiO2 nanostructures were fabricated by electrochemical anodic oxidation of Ti films and Ti nanorods prepared by GLAD in the oxygen free atmosphere at 0.1 Pa of Ar.
Anodic Oxidation of Titanium Nanorods
Authors: Turkevych Ivan , Pihosh Yuriy , Wang Zhong-Sheng , Hara Koujirou , Kondo Michio
Published: March 2009

Anodic oxidation of Ti nanorods prepared by glancing angle deposition has been used for the fabrication of brush-type nanostructures of TiO2. During the anodization process, small TiO2 nanotubes grew on the walls of Ti nanorods until all Ti was converted to the oxide. As a result we obtained highly porous material that consists of TiO2 nanotubes arranged in shells around central oxide cores, which replaced former Ti nanorods. The combination of glancing angle deposition and anodization techniques creates unique possibilities for the fabrication of TiO2 nanostructures with a hierarchical ordering.
Highly Uniform Aluminum Oxy-hydroxide Nanofiber from Porous Anodic Alumina
Authors: Jha Himendra , Kikuchi Tatsuya , Sakairi Masaotoshi , Takahashi Hideaki
Published: March 2009

A simple and effective method for the synthesis of aluminum oxy-hydroxide nanofiber is demonstrated. In this method, porous anodic oxide film of aluminum (porous anodic alumina) is used to synthesize the nanofibers, where it acts both as a precursor as well as the template. Initially, the porous oxide film is hydrothermally treated for the formation of hydroxide (boehmite or pseudoboehmite) inside the oxide pores, and then the porous oxide is selectively etched from the film, using tri-sodium citrate solution, leaving the hydroxide intact. The method results in highly uniform aluminum oxy-hydroxide nanofibers. The size (diameter) of the nanofiber was controlled by controlling the size of the pores in the anodic oxide film.
New Oxygen Reduction Electrocatalysts Based on Oxide Nanosheet Materials
Authors: Saito Morihiro , Akeboshi Yuya , Ohno Naotaka , Kuwano Jun , Shiroishi Hidenobu , Uchimoto Yoshiharu
Published: March 2009

Three types of titania nanosheet-based materials, a H3O+-exchanged rolled nanosheet (nanotube) (H3O+-NT(Ti)), layered titanate (H3O+-RG(Ti)), and restacked titania nanosheets (H3O+-RE(Ti)) were synthesized by soft chemical methods, and their oxygen reduction reaction (ORR) activities were examined by semi-steady-state voltammetry with a rotating ring-disc electrode at 70{degree sign}C in 0.05 M H2SO4. All the samples showed similar onset potentials (Eon) of the ORR current, ~ 0.50 vs. reversible hydrogen electrode, while the efficiencies (Eff4) of the 4-electron reduction of oxygen depended on their nanostructures, i.e. the stacking morphology of nanosheets, specific surface area and kinds of inserted cation between the nanosheets. Both H3O+-RG(Ti) and H3O+-RE(Ti) samples showed higher Eff4 values as compared with Cs+-form layered titanate (Cs+-RG(Ti)) and the H+-form restacked titania nanosheets (H+-RE(Ti)). This reveals that the H3O+ions and the number of the active sites for ORR are related to the ORR activity. The H3O+-RE(Ti) exhibited the best Eff4 value (> 90%), which is comparable to that of a conventional 20 mass% Pt/C catalyst. The effects on the ORR activity are also observed in alkaline (0.1 M KOH) aqueous solution, i.e. the H3O+-RE(Ti) exhibited the best Eon (~0.8 V) and Eff4 values (> 90%).
Sonoelectrochemical Deposition of Functional Composite Layers
Authors: Schneider Oliver , Martens Sladjana , Argirusis Christos
Published: March 2009

Ultrasound was applied for the electrodeposition of metal/ceramic and metal/metal composites. Ni/ceria composites were deposited from Watts and sulfamate based electrolytes containing dispersed ceria using ultrasonic irradiation for the deagglomeration of oxide particles. The electrochemical deposition of silver at the tip of an ultrasonic horn probe using pulsed ultrasound was explored for its potential to electrodeposit Ni/Ag composites. First results are presented. Sonoelectrochemical processes were in part monitored in-situ by the electrochemical quartz crystal microbalance technique. Compositions of the electrodeposits were analyzed by energy dispersive spectroscopy and in part by electron probe microanalysis.
Effect of Silicotungstic Acid on Properties of Pulse Electrodeposited Zinc Selenide Films
Authors: Murali K. R. , Dhanapandiyan S. , Manoharan C.
Published: March 2009

Zinc selenide(ZnSe) thin films were pulse deposited for the first time using polycyclic acid. The films exhibited hexagonal structure. The band gap of the films varied in the range of 2.7 - 3.1 eV as the concentration of silicotungstic acid increased. Atomic force microscopy indicated grain size decreased from 60 - 15 nm after addition of silicotungstic acid. Laser Raman spectrum exhibited LO phonons corresponding to ZnSe. Photoluminescence spectra peaks at 675 nm. As the concentration of silicotungstic acid increases, the PL emission peak shifts to shorter wavelenghths.
Ultrasmooth Gold as a Top Metal Electrode for Molecular Electronic Devices
Authors: Coll Mariona , Hacker Christina A. , Miller Lauren H. , Hines Daniel R. , Williams Ellen D. , Richter Curt A.
Published: March 2009

In the emerging area of molecular electronics, fabrication of reliable metallic contacts remains one of the most critical challenges. Nanotransfer printing (nTP) is an attractive low-cost non-destructive technique to provide contact to organic monolayers. This work introduces the use of ultrasmooth gold on polymeric substrates, fabricated by using an nTP-based method, as a novel means to form metal-molecule-silicon molecular electronic test structures. We have used self-assembly to fabricate high-quality COOH-terminated alkanethiols on ultrasmooth gold. Covalent bonding to the H-Si(111) substrate was achieved through the application of moderate pressure and temperature. Because of the critical role of molecular conformation on electrical properties, infrared spectroscopy was used to explore the influence of these two parameters (P,T) on molecular ordering. Moderate conditions effectively fabricate high-quality reproducible molecular electronic test structures preserving molecular conformation with molecules bonded to both electrodes. This work proves a useful strategy for the development of hybrid nanoelectronic devices.
Arrayed Si/SiGe Nanowire Heterostructure Formation via Au-catalyzed Wet Chemical Etching Method
Authors: Wang Xiaodong , Pey K.L. , Choi W.K. , Ho C.K.F. , Fitzgerald Eugene A. , Antoniadis D.
Published: March 2009

Aligned Si/SiGe nanowire heterostructures have been formed using Au-assisted top-down chemical etching method combined with nanosphere lithography. Since the nanowires are formed from the as-grown films, the heterostructures along the axial axis of the formed nanowires, i.e. axial heterostructures, are replica of the grown layered film structure. Thus SiGe nanowire heterostructures can be readily formed along the axis using an as-grown heterostructured film. By applying a nanosphere lithography technique, the space, diameter, and density of the nanowires can be controlled and readily formed at specifically defined area. Because of the flexibility and simplicity of this method, nanowires with embedded junctions of different doping characteristics and Si/Ge concentrations can be fabricated easily. Si and its Ge alloy nanowires and one dimensional heterostructures formed using this method may have great potential for vertical logic, photovoltaic and memory device applications.
Luminescent Properties of CdSe Quantum Dots Subjected to MBE GaN Growth Temperatures
Authors: Hodge Michael D. , Pagan Jennifer , Burkhart Casey , Patel Kinnari , Stokes E. B.
Published: March 2009

CdSe semiconductor quantum dots have received an enormous amount of attention due to their intense luminescent properties in the middle of the visible spectrum, By attempting to emulate the quantum confinement properties of the successful GaN/InGaN blue light emitting diode (LED), an efficient inorganic LED in the deep green spectral region could theoretically be achieved by incorporating CdSe quantum dots within the active region. The semiconductor growth process would expose the quantum dots to temperatures at a minimum of 600{degree sign}C. This paper reports on a series of anneal experiments to determine the luminescent properties of colloidal CdSe quantum dots on GaN that were annealed at 350{degree sign}C and 620{degree sign}C. The experiment took place in a MBE chamber under high vacuum loaded with quantum dot samples to simulate the environment to simulate the environment of epitaxial growth. We report on the quantum dots subsequent luminescence and a resulting blue shift in peak emission.
Kinetics Study of Ozone Gas Enhanced Passivation of Pure Iron
Authors: Nanjo Hiroshi , Suzuki Yasunori , Hayasaka Junko , Bayoumi Hassan Fathy M. , Ishikawa Ikuo , Kanakubo Mitsuhiro , Aizawa Takafumi , Aida Tsutomu , Onagawa Jun
Published: March 2009

Passive film was exposed by ozone gas to study the applicability of improving the surface structure such as atomically flat terrace. Because water and/or other minor species were contained in the passive oxide film, it is expected that ozone gas oxidized some of them and help the reconstruction of passive film toward stable crystal phase of oxides. The thickness increased remarkably by passivation at 800 mV (Ag/AgCl), but increased slightly in ozone gas and decreased in air due to reconstruction after rapid growth of oxides by the passivation at 800 mV. The thickness decreased by passivation at -350 mV, but increased apparently by ozone exposure. The widest terrace width was obtained by passivation at 800 mV and the subsequent ozone gas exposure. The terrace width with atomic scale flatness correlated with the corrosion resistance except for the increase in oxides film thickness.
Origin of Nanobubble - Formation of Stable Vacancy in Electrolyte Solution
Authors: Aogaki Ryoichi , Miura Makoto , Oshikiri Yoshinobu
Published: March 2009

As an elementary structure of nanobubbles, vacancy, i.e., a kind of vacuum void stably exists in a liquid electrolyte solution, which is composed of an inner wall negatively charged by anion and a positively charged ionic atmosphere (R. Aogaki, Electrochemistry 76, 458 (2008)). As a result, a strong repulsing pressure induced by the attraction of the ionic atmosphere is balanced with the action of surface tension. Coalescence of vacancies guarantees the same structure as vacancy, so that the internal pressure of nano-bubbles is kept low, almost equal to the atmospheric pressure. At the same time, the variation in the chemical potential of the homogeneous formation of nano-bubbles is calculated, and it is shown that after passing a critical state corresponding to a radius of 1 nm, nanobubbles are stably created.
Cu Filling Characteristics in Through-Si Via Holes by Electroless Plating with Addition of Inhibitors
Authors: Inoue Fumihiro , Koyanagi Mitsumasa , Fukushima Takafumi , Yamamoto Kazuhiro , Tanaka S. , Wang Zenglin , Shingubara Shoso
Published: March 2009

In order to realize low resistance through-Si via (TSV) electrodes, Cu electroplating is one of the most promising methods. However, with an increase of the aspect ratio of TSV, a formation of conductive seed layer prior to Cu electroplating is becoming more and more difficult. We propose an alternative approach using the electroless plating of Cu, which utilize displacement plating without catalyst. This method is effective for fabricating a low resistance TSV when combined with a barrier layer which is composed of tungsten (W). We found that an addition of Cl ions drastically suppressed the pinch-off at the entrance of the TSV, and it enabled conformal Cu deposition for high aspect ratio TSVs.
Shape Evolution of Electrodeposited Bumps with Shallow and Deep Cavity
Authors: Kondo K. , Suzuki Yushi , Saito Takeyasu , Okamoto Naoki
Published: March 2009

For aspect ratio of 0.25, the initial bump shape is flat for the 0 rpm rotating disk electrode. The bump shapes have humps on the upper stream sides for the 10 and 20 rpm. The hump on the upper stream side shifts to the down stream side for the 100 rpm. The vortices form both at the cathode and photoresist corners on the upper and lower sides. The upper stream side has humps both for the 10 and 20 rpm and the hump shifts to the down stream side at 100 rpm. For aspect ratio of 3.3, the cross section of the initial bumps became flat for all the rotating disk electrode rotation speeds of 0, 10, 20 and 100 rpm. Two vortices were generated at all the rotation speeds. The vortices did not reach the cathode. The bump cross section became flat because the transport is controlled by diffusion.
Application of Pourbaix Diagrams to the Selective Etching of Thin Metal Layers
Authors: Leibovitz Jacques
Published: March 2009

The highest density of interconnection in electronic packaging is obtained with solder bumps built over the Al pads on integrated circuit chips. A thin metal layer called under-bump metallization (UBM) mediates the attachment of the solder bumps to the Al pad. The UBM consists of a number of thin metal sub-layers. One example consists of Cr/NiV/Au. The UBM is patterned by consecutive selective etching of the sub-layers through a patterned photo-resist. During the development of the etching process, the consecutive etching of the Au and NiV sub-layers yielded a bottom Cr sub-layer damaged by inter-granular corrosion. However, of a layer composed of only Cr/NiV (no Au), the selective etching of the NiV sub-layer left the Cr sub-layer undamaged. With an understanding of the sub-layers structures and the help of Pourbaix diagrams, the problem was solved.
Change in the Film Properties According to the Various Electroplating Conditions
Authors: Kim Myung Jun , Cho Sung Ki , Kim Jae Jeong
Published: March 2009

The film properties of metal lines are a matter of grave concern as the metal line shrank. To improve the electromigration resistance and resistivity, many variables should be changed such as mean current density, addition of additives, and electroplating modes. The mean current density affects the overpotential which was main factor of nucleation. To obtain the better film properties, pulse and pulse-revere plating were applied. The peak intensity ratio increased through surface relaxation during off-time and film roughness slightly decreased by high incident potential. And the dissolution affects the film characteristics in pulse-reverse plating even pulse-reverse plating could apply high incident potential. The anodic process decreased the film roughness by selective dissolution at protrusions, however it could reduce the peak intensity ratio. Through pulse and pulse-reverse plating, the film properties were changed and improved in the aspect of resistivity and peak intensity ratio.
Optimization of Pd Activation on Ta Substrate for Cu Electroless Deposition Using Electrochemical Method
Authors: Lim Taeho , Koo Hyo-Chol , Kim Jae Jeong
Published: March 2009

Ta is widely used as both a diffusion barrier layer and adhesion layer between Cu interconnects and dielectric materials. Because Ta has no catalytic activity on Cu electroless deposition, it needs an activation before the Cu electroless deposition. This study focused on the oxidation of several reducing agents on Pd particles formed on Ta surface. By an electrochemical analysis, it was observed that the higher Pd nuclei density showed the higher oxidation current, and the position of the peak current shifted more negatively with the higher Pd nuclei density. Using this electrochemical method, the optimization of Pd activation was achieved, and it was successful on the formation of thin Cu seed layer by Cu electroless deposition.
Nanoscopic Evaluation of Metals Diffused into the Surface Layer
Authors: Yamamoto Shin-ichi , Yamada Hirofumi
Published: March 2009

In this study, we developed a magnetic-force-controlled atomic force microscopy (MFC-AFM) system that can be controlled by adjusting the magnetic force from an external magnetic field. In the method using this system, the stiffness of the surface of a sample is measured while a vibrating probe, to which force is applied from an external magnetic field, scans the surface. By fabricating a cantilever with a magnet and using diamond as the probe material, the measurement of hard samples becomes possible. We also succeeded in imaging the difference in stiffness between a Ni material diffused over a Au electrode and a Au material.
Inflammation-induced, 3′UTR-dependent translational inhibition of Hsp70 mRNA impairs intestinal homeostasis
Authors: Hu Shien , Zhu Xiaorong , Triggs Joseph R. , Tao Yun , Wang Yunwei , Lichtenstein Lev , Bissonnette Marc , Musch Mark W. , Chang Eugene B.
Published: March 2009

Although the inducible heat shock protein 70 (Hsp70) is essential for maintaining intestinal homeostasis in colitis, it is translationally downregulated in inflamed colonic mucosa, paradoxically rendering the gut more susceptible to injury. We examined the basis for this process by analyzing the role of untranslated regions (UTR) of Hsp70 mRNA in inflammation-associated downregulation in vitro and in vivo. Using luciferase-reporter assays in young adult mouse intestinal epithelial cells, we determined that cytokine-induced translational inhibition of Hsp70 mRNA was mediated by the 3′UTR, but not 5′UTR. In vivo, dextran sodium sulfate (DSS) colitis was induced in wild-type (WT) and villin-promoter regulated “UTR-less” Hsp70 transgenic (TG) mice, the latter exhibiting intestinal epithelial-specific transgene expression. Progressive downregulation of colonic Hsp70 protein expression was observed in WT, but not in TG, mice with increasing severity of mucosal inflammation, confirming the essential role of the 3′UTR in mediating inflammation-associated downregulation of Hsp70. Hsp70 TG mice demonstrated significantly lower endoscopic and histological inflammation scores in DSS-induced colitis than WT. In conclusion, downregulation of Hsp70 expression in inflamed mucosa is mediated by translational inhibition requiring the 3′UTR, resulting in increased mucosal injury. By forcing intestinal epithelial-specific Hsp70 expression in vivo, the severity of experimentally induced colitis was significantly reduced.
Differential expression and regulation of ADAM17 and TIMP3 in acute inflamed intestinal epithelia
Authors: Cesaro Annabelle , Abakar-Mahamat Abakar , Brest Patrick , Lassalle Sandra , Selva Eric , Filippi Jérôme , Hébuterne Xavier , Hugot Jean-Pierre , Doglio Alain , Galland Franck , Naquet Philippe , Vouret-Craviari Valérie , Mograbi Baharia , Hofman Paul M.
Published: March 2009

The acute phase of Crohn's disease (CD) is characterized by a large afflux of polymorphonuclear leukocytes (PMNL) into the mucosa and by the release of TNF-α. Conversion of inactive TNF-α into an active form requires the cleavage of a transmembrane TNF-α precursor by the TNF-α-converting enzyme (ADAM17), a protease mainly regulated by the tissue inhibitor of metalloproteinase 3 (TIMP3). The aim of the present study was to investigate in an in vitro model of PMNL transepithelial migration and in the intestinal mucosa of patients with CD the expression and regulation of ADAM17 and TIMP3 in intestinal epithelial cells (IEC). ADAM17 and TIMP3 expression was analyzed by Western blotting, RT-PCR, confocal microscopy, and immunohistochemistry by using the T84 model and digestive biopsies. ADAM17 expression in IEC was increased at a posttranscriptional level during the early phase (from 2 to 4 h) of PMNL transepithelial migration whereas TIMP3 was only increased 24 h later. TNF-α induced an early upregulation of ADAM17 in T84 cells, whereas PMNL adhesion, H2O2, or epithelial tight junction opening alone did not affect the amount of ADAM17. Immunohistochemistry of intestinal biopsies revealed that strong expression of ADAM17 was associated with a high activity of CD. In contrast, TIMP3 was very poorly expressed in these biopsies. ADAM17 and TIMP3 profiling did not correlated with the NOD2/CARD15 status. The ADAM17 activity was higher both in the early phase of PMNL transepithelial migration and in active CD. These results showed early posttranscriptional upregulation of ADAM17 in IEC linked to PMNL transepithelial migration and a high activity of CD.
Activation of NF-κB is a critical element in the antiapoptotic effect of anesthetic preconditioning
Authors: Lu Xiyuan , Liu Hong , Wang Lianguo , Schaefer Saul
Published: March 2009

Anesthetic preconditioning (APC), defined as brief exposure to inhalational anesthetics before cardiac ischemia-reperfusion (I/R), limits injury in both animal models and in humans. APC can result in the production of reactive oxygen species (ROS), and prior work has shown that APC can modify activation of NF-κB during I/R, with consequent reduction in the expression of inflammatory mediators. However, the role of NF-κB activation before I/R is unknown. Therefore, these experiments tested the hypothesis that APC-induced ROS results in activation of NF-κB before I/R, with consequent increased expression of antiapoptotic proteins such as Bcl-2 and decreased apoptosis. Experiments utilized an established perfused heart rat model of sevoflurane APC and I/R. The role of NF-κB was defined by a novel method of transient inhibition of the regulatory kinase IKK using the reversible inhibitor SC-514. In addition to functional measures of left ventricular developed and end-diastolic pressure, phosphorylation of IκBα and activation of NF-κB were measured along with cytosolic protein content of Bcl-2, release of cytochrome c, and degradation of caspase-3. APC resulted in ROS-dependent phosphorylation of IκBα and activation of NF-κB before I/R. APC also increased the expression of Bcl-2 before I/R. In addition to functional protection following I/R, APC resulted in lower release of cytochrome c and caspase-3 degradation. These protective effects of APC were abolished by transient inhibition of IκBα phosphorylation and NF-κB activation by SC-514 followed by washout. ROS-dependent activation of NF-κB by APC before I/R is a critical element in the protective effect of APC. APC reduces apoptosis and functional impairment by increasing Bcl-2 expression before I/R. Interventions that increase NF-κB activation before I/R should protect hearts from I/R injury.
Simulated microgravity-induced aortic remodeling
Authors: Tuday Eric C. , Nyhan Daniel , Shoukas Artin A. , Berkowitz Dan E.
Published: March 2009

We have previously shown that microgravity and simulated microgravity induce an increase in human and rat aortic stiffness. We attempted to elucidate the mechanism(s) responsible for this increase in stiffness. We hypothesize that an alteration in vessel wall collagen or elastin content or in extracellular matrix (ECM) cross-linking either individually or in a combination is responsible for the increased vessel stiffness. Rats underwent hindlimb unweighting (HLU) for a period of 7 days to simulate microgravity. The contribution of ECM cross-linking to the vessel wall stiffness was evaluated by measuring aortic pulse wave velocity following inhibition of the cross-linking enzymes lysyl oxidase (LOX) and transglutaminase (tTG) and the nonenzymatic advanced glycation end product cross-linking pathway during HLU. Aortic collagen and elastin content was quantified using established colorimetric assays. Collagen subtype composition was determined via immunofluorescent staining. The increase in aortic pulse wave velocity after HLU was significantly attenuated in the LOX and tTG inhibition groups compared with saline (1.13 ± 0.11 vs. 3.00 ± 0.15 m/s, LOX vs. saline, P < 0.001; 1.16 ± 0.25 vs. 3.00 ± 0.15 m/s, tTG vs. saline, P < 0.001). Hydroxyproline content, a measure of collagen content, was increased in all groups after HLU (2.01 ± 0.62 vs. 3.69 ± 0.68% dry weight, non-HLU vs. HLU, P = 0.009). Collagen subtype composition and aortic elastin content were not altered by HLU. Together, these data indicate that HLU-induced increases in aortic stiffness are due to both increased aortic collagen content and enzyme cross-linking activity.
Effects of stent sizing on endothelial and vessel wall stress: potential mechanisms for in-stent restenosis
Authors: Chen Henry Y. , Hermiller James , Sinha Anjan K. , Sturek Michael , Zhu Luoding , Kassab Ghassan S.
Published: March 2009

Stent sizing and apposition have been shown to be important determinants of clinical outcome. This study evaluates the mechanical effects of undersizing and oversizing of stents on endothelial wall shear stress (WSS) and vessel wall stress to determine a possible biomechanical mechanism of in-stent restenosis and thrombosis. Three-dimensional computational models of stents, artery, and internal fluid were created in a computer-assisted design package, meshed, and solved in finite element and computational fluid dynamic packages. The simulation results show that the effects of various degrees of undersizing on WSS, WSS gradient, and oscillatory shear index were highly nonlinear. As the degree of undersizing increased, the heterogeneity of WSS became smaller. The WSS distribution for the 20% undersizing was smooth and uniform, whereas the 5% case was very heterogeneous. The combination of lower WSS and higher WSS gradient and oscillatory shear index in the 5% undersized case may induce neointimal hyperplasia or thrombosis. Additionally, the oversizing simulation results show that the maximum intramural wall stress of the 20% oversizing case is significantly larger than the maximum stress for the 10% and zero oversizing cases. Edge stress concentration was observed, consistent with the restenosis typically observed in this region. This study demonstrates that proper sizing of stent is important for reducing the hemodynamic and mechanical disturbances to the vessel wall. Furthermore, the present findings may be used to improve stent design to reduce endothelial flow disturbances and intramural wall stress concentrations.
SR-BI Selective Lipid Uptake
Authors: de Beer Maria C. , Webb Nancy R. , Whitaker Nathan L. , Wroblewski Joanne M. , Jahangiri Anisa , van der Westhuyzen Deneys R. , de Beer Frederick C.
Published: March 2009

Objective—

The purpose of this study was to investigate the interaction of SAA and SR-BI in remodeling of acute phase HDL (AP HDL).

Methods and Results—

We used SAA and SR-BI adenoviral vector expression models to study the interaction between these entities. SR-BI processing of mouse AP HDL generated progressively smaller discreet HDL particles with distinct apolipoprotein compositions. SR-BI actions segregated apolipoproteins with the smallest particles containing only apoA-I. Larger remnants contained apoA-I, apoA-II, and SAA. Small apoA-I only particles failed to associate with preformed HDL, whereas larger remnants readily did. The presence of SAA on SR-BI-processed HDL particles propelled apoA-I to a small lipid-poor form and accelerated apoA-I catabolism.

Conclusions—

Data indicate that after core and surface HDL lipid perturbation by SR-BI, SAA propels apoA-I to a small lipid-poor form while accelerating HDL metabolism.
Chylomicronemia With a Mutant GPIHBP1 (Q115P) That Cannot Bind Lipoprotein Lipase
Authors: Beigneux Anne P. , Franssen Remco , Bensadoun André , Gin Peter , Melford Kristan , Peter Jorge , Walzem Rosemary L. , Weinstein Michael M. , Davies Brandon S.J. , Kuivenhoven Jan A. , Kastelein John J.P. , Fong Loren G. , Dallinga-Thie Geesje M. , Young Stephen G.
Published: March 2009

Objective—

GPIHBP1 is an endothelial cell protein that binds lipoprotein lipase (LPL) and chylomicrons. Because GPIHBP1 deficiency causes chylomicronemia in mice, we sought to determine whether some cases of chylomicronemia in humans could be attributable to defective
GPIHBP1
proteins.

Methods and Results—

Patients with severe hypertriglyceridemia (n=60, with plasma triglycerides above the 95th percentile for age and gender) were screened for mutations in
GPIHBP1
. A homozygous
GPIHBP1
mutation (c.344A>C) that changed a highly conserved glutamine at residue 115 to a proline (p.Q115P) was identified in a 33-year-old male with lifelong chylomicronemia. The patient had failure-to-thrive as a child but had no history of pancreatitis. He had no mutations in
LPL
,
APOA5
, or
APOC2
. The Q115P substitution did not affect the ability of GPIHBP1 to reach the cell surface. However, unlike wild-type GPIHBP1, GPIHBP1-Q115P lacked the ability to bind LPL or chylomicrons (
d
< 1.006 g/mL lipoproteins from
Gpihbp1
−/−
mice). Mouse GPIHBP1 with the corresponding mutation (Q114P) also could not bind LPL.

Conclusions—

A homozygous missense mutation in
GPIHBP1
(Q115P) was identified in a patient with chylomicronemia. The mutation eliminated the ability of GPIHBP1 to bind LPL and chylomicrons, strongly suggesting that it caused the patient’s chylomicronemia.
Diffusion Spectrum MRI Tractography Reveals the Presence of a Complex Network of Residual Myofibers in Infarcted Myocardium
Authors: Sosnovik David E. , Wang Ruopeng , Dai Guangping , Wang Teresa , Aikawa Elena , Novikov Mikhael , Rosenzweig Anthony , Gilbert Richard J. , Wedeen Van J.
Published: March 2009

Background—

Changes in myocardial microstructure are important components of the tissue response to infarction but are difficult to resolve with current imaging techniques. A novel technique, diffusion spectrum MRI tractography (DSI tractography), was thus used to image myofiber architecture in normal and infarcted myocardium. Unlike diffusion tensor imaging, DSI tractography resolves multiple myofiber populations per voxel, thus generating accurate 3D tractograms, which we present in the myocardium for the first time.

Methods and Results—

DSI tractography was performed at 4.7 T in excised rat hearts 3 weeks after left coronary artery ligation (n=4) and in 4 age-matched controls. Fiber architecture in the control hearts varied smoothly from endocardium to epicardium, producing a symmetrical array of crossing helical structures in which orthogonal myofibers were separated by fibers with intermediate helix angles. Fiber architecture in the infarcted hearts was severely perturbed. The infarct boundary in all cases was highly irregular and punctuated repeatedly by residual myofibers extending from within the infarct to the border zones. In all infarcts, longitudinal myofibers extending toward the basal-anterior wall and transversely oriented myofibers extending toward the septum lay in direct contact with each other, forming nodes of orthogonal myofiber intersection or contact.

Conclusions—

DSI tractography resolves 3D myofiber architecture and reveals a complex network of orthogonal myofibers within infarcted myocardium. Meshlike networks of orthogonal myofibers in infarcted myocardium may resist mechanical remodeling but also probably increase the risk for lethal reentrant arrhythmias. DSI tractography thus provides a new and important readout of tissue injury after myocardial infarction.
Acquisition of Brain Na Sensitivity Contributes to Salt-Induced Sympathoexcitation and Cardiac Dysfunction in Mice With Pressure Overload
Authors: Ito Koji , Hirooka Yoshitaka , Sunagawa Kenji
Published: March 2009

In animal models of salt-sensitive hypertension, high salt augments sympathetic outflow via central mechanisms. It is not known, however, whether pressure overload affects salt sensitivity, thereby modifying central sympathetic outflow and cardiac function. We induced left ventricular hypertrophy with aortic banding in mice. Four weeks after aortic banding (AB-4), the left ventricle wall thickness was increased without changing the percentage fractional shortening. AB-4 mice were then fed either a high-salt (8%) diet or regular-salt diet for additional 4 weeks. Cardiac dysfunction, wall thickness, and 24-hour urinary catecholamine excretion were increased with high-salt diet compared with regular-salt diet. We then examined brain Na sensitivity. Intracerebroventricular infusion of high-Na (0.2 mol/L) artificial cerebrospinal fluid into AB-4 mice and mice Sham-4 increased urinary catecholamine excretion, arterial pressure, and heart rate more in AB-4 mice than in Sham-4 mice. Intracerebroventricular infusion of an epithelial Na channel blocker (benzamil) into mice with high-salt diet significantly decreased urinary catecholamine excretion and improved cardiac function. Infusion of either an angiotensin II type 1 receptor blocker or a Rho-kinase inhibitor also attenuated the salt-induced sympathetic hyperactivation and cardiac dysfunction in mice with high-salt diet. The levels of angiotensin II type 1 receptor and phosphorylated moesin, a substrate of Rho-kinase, were significantly greater in AB-4 mice than in Sham-4 mice. These results suggest that mice with pressure overload acquire brain Na sensitivity because of the activation of epithelial Na channel via Rho-kinase and angiotensin II, and this mechanism contributes to salt-induced sympathetic hyperactivation, further pressure overload, and cardiac dysfunction.
Inducible Expression of Active Protein Phosphatase-1 Inhibitor-1 Enhances Basal Cardiac Function and Protects Against Ischemia/Reperfusion Injury
Authors: Nicolaou Persoulla , Rodriguez Patricia , Ren Xiaoping , Zhou Xiaoyang , Qian Jiang , Sadayappan Sakthivel , Mitton Bryan , Pathak Anand , Robbins Jeffrey , Hajjar Roger J. , Jones Keith , Kranias Evangelia G.
Published: March 2009

Ischemic heart disease, which remains the leading cause of morbidity and mortality in the Western world, is invariably characterized by impaired cardiac function and disturbed Ca
2+
homeostasis. Because enhanced inhibitor-1 (I-1) activity has been suggested to preserve Ca
2+
cycling, we sought to define whether increases in I-1 activity in the adult heart may ameliorate contractile dysfunction and cellular injury in the face of an ischemic insult. To this end, we generated an inducible transgenic mouse model that enabled temporally controlled expression of active I-1 (T35D). Active I-1 expression in the adult heart elicited significant enhancement of contractile function, associated with preferential phospholamban phosphorylation and enhanced sarcoplasmic reticulum Ca
2+
-transport. Further phosphoproteomic analysis revealed alterations in proteins associated with energy production and protein synthesis, possibly to support the increased metabolic demands of the hyperdynamic hearts. Importantly, on ischemia/reperfusion-induced injury, active I-1 expression augmented contractile function and recovery. Further examination revealed that the infarct region and apoptotic as well as necrotic injuries were significantly attenuated by enhanced I-1 activity. These cardioprotective effects were associated with suppression of the endoplasmic reticulum stress response. The present findings indicate that increased I-1 activity in the adult heart enhances Ca
2+
cycling and improves mechanical recovery, as well as cell survival after an ischemic insult, suggesting that active I-1 may represent a potential therapeutic strategy in myocardial infarction.