bluuebunny/crossref_metadata_2025 huggingface dataset:
Design for Optimized Electromechanical Transduction in Ionic Polymer Transducers Fabricated With Architecturally Controlled Ionomers
Authors: Duncan Andrew J. , Long Timothy E. , Leo Donald J.
Published: February 2010

Ionic polymer transducers (IPT) are devices composed of ionomeric membranes, high surface area electrodes, and ion-conducting electrolytes that are capable of electromechanical transduction. This study aims to optimize the interactions between all three of these components to design a high performance IPT with novel ionomers. Equivalent circuit modeling of impedance data allowed for estimations of IPT capacitance due to changes in the compositions of the electrodes. Various methods for control of electrolyte uptake resulted in a range of ionic conductivity when combined with novel ionomers that vary in polymer backbone architecture and charge content. Although the ionic liquid was found to dominate the magnitude of the conductivity, the pathway for uptake was significant in determination of the overall maximum values. Combination of these optimized parameters for capacitance and ionic conductivity identified design criteria for potentially high performance IPTs to investigate the benefits of these novel ionomers in electroactive devices.
Yaw Angle and Speed Control of Underwater Vehicle Propelled by Ionic Polymer Metal Composite (IPMC) Actuator
Authors: Gutta Shivakanth , Yim Woosoon , Trabia Mohamed B.
Published: February 2010

In this paper, a closed-loop feedback controller is developed for the underwater vehicle propelled by ionic polymer metal composite (IPMC) actuator. The dynamics of the underwater vehicle with IPMC actuator are modeled using the large deflection beam model and hydrodynamic forces due to its interaction with the surrounding water. The hydrodynamic force coefficients are identified based on the results of extensive computational fluid dynamics (CFD) simulations. The path of the vehicle is controlled by simultaneously controlling the yaw angle and speed of the vehicle using the proportional controllers. Simulation data is utilized to find the relation between control input parameters namely, amplitude and bias of the voltage applied to the IPMC, and yaw angle and speed of the vehicle. In the simulations, frequency of the control input is assumed to be fixed. Simulation results show that the proposed controller can be effectively used to steer the under water vehicles propelled by IPMC.
Enhanced Piezoelectric Impedance Approach for Damage Detection With Circuitry Integration
Authors: Wang X. , Tang J.
Published: February 2010

Piezoelectric impedance-based damage detection approach has been recognized to be sensitive to small-sized damage, as the impedance information can be measured at relatively high frequency range. To enhance this approach, recently an innovative scheme is developed by integrating the inductive circuitry serially with the piezoelectric transducer. With the resonant effect due to such inductive circuitry integration, the measurement amplitude is greatly amplified. It has been identified that the change of admittance measurement before and after damage occurrence is increased by an order-of-magnitude, which yields much increased detection sensitivity. In this research, we first attempt to enhance this inductive circuitry scheme by integrating the negative capacitance element. With the peak magnitude of the curve of the admittance change remaining high, the magnitude of the admittance change away from the resonances is greatly increased, which means the amplification effect of the inductive circuitry becomes effective in a wider frequency range. Then we make further improvement by connecting the resistor (used to facilitate the admittance measurement) parallel with the inductor. This results in the amplification of the voltage across the resistor, and thus further increases the signal-to-ratio of admittance measurement. Extensive numerical and experimental studies are carried out to demonstrate the effectiveness of the proposed enhancements.
Hierarchical Self-Assembly of Tryptic Peptides From Wheat Gluten
Authors: Athamneh Ahmad , Barone Justin
Published: February 2010

We have prepared nanocomposites in one step by hydrolyzing wheat gluten (WG) with trypsin and then drying the solution. Some tryptic peptides from WG can self-assemble into fibrous structures under benign conditions (37 °C, pH 8) to form a reinforcing phase while the balance do not to form the matrix phase. Here we describe the characterization of the self-assembled fibers, which were hierarchically structured and showed organization from the nanometer to the micrometer scale. The basic building block of the fiber was a stack of beta–sheets. Scanning and transmission electron micrographs showed large fibers about 10–15 μm in diameter with left-handed helical configuration and appeared to be bundles of 10–20 nm diameter fibrils. Preliminary investigation suggested that the elastic modulus of the WG-based fibers was 0.16 ± 0.03 GPa, consistent with reported values for natural protein fibers. Fourier transform infrared spectroscopy, X-ray diffraction, and thioflavin-T binding assay indicated that the framework of the fibrils was composed of cross-beta structures, where beta-strands ran perpendicular to the fiber axis.
Growth Control and Properties of Fullerene Nanofibers
Authors: Miyazawa Kun’ichi , Hotta Kayoko , Kato Ryoei , Fujii Jun , Kizuka Tokushi
Published: February 2010

Fullerene nanofibers are the fine needle-like crystals composed of fullerene molecules and can be synthesized in a solution at ambient temperature and atmosphere. The growth control of the fullerene nanofibers are necessary in order to apply them for practical uses. We have developed a method to synthesize short fullerene nanowhiskers with a uniform length suitable for the electrodes in solar cells and fuel cells. This paper reports the synthesis of C60 nanofibers, including their properties and application.
Finite Element Martensite Ratio Derivation on NiTi via Measurable Criteria of Strain Rate
Authors: Amini Abbas , Mehdigholi Hamid , Elahinia Mohammad
Published: February 2010

The shape memory alloys (SMAs) and smart composites have a large use in high and low level industry, while a lot of research is being done in this field. The existence of smart composite structures is because of the advance mechanical benefits of the above materials. This work refers to dynamic and quasi static nonlinear explanation of these materials. After mathematical model consideration on the rate of strain, a model which is about martensite ratio of NiTi has been presented. This work has been done because of the high sensitivity of these materials to strain rate and use of visual and measurable engineering criteria to access other variables. As the martensite ratio is not engineering measurable amount, it needs to have macro scale property to measure this important nano scale criteria. Relative experiments are done to show the rate dependency of NiTi.
Smart Materials, Characteristics, Applications and Modeling
Authors: Amini Abbas , Mehdigholi Hamid , Elahinia Mohammad
Published: February 2010

This paper reviews the research results, characteristics, modeling and recent developments of smart materials specially shape memory alloys and smart composites. This field even involves smart fluids and it opens a new era to find new smart materials for eliminating their flaws by combination with other advanced materials. The purpose of this paper is showing the current research coordinate. These issues help to have a technological reference for these materials. At the end, there is specific attention to Nitinols and by experiments is shown that Oliver-Pharr formulation does not cover these material behaviors. These experiments cover some important aspects of Nitinols which have not been considered by current researches.
Size Effect on the Phase Transformation of In-21at%Tl Nanowires
Authors: Phillips Francis R. , Zheng Hongxing , Lagoudas Dimitris C. , Karaman Ibrahim
Published: February 2010

In this work, the interaction between the size effect and the thermomechanically induced phase transformation for SMAs composed of Indium-Thallium (InTl) is analyzed. An In-21at%Tl alloy is first fabricated, from which In-21at%Tl nanowires are subsequently produced. Using the mechanical pressure injection system, the bulk alloy is pressed into pores of an Anodized Aluminum Oxide (AAO) template to fabricate the nanowires. The diameter of these nanowires can be altered by changing the anodization parameters of the AAO templates (≈20nm–750nm). The critical diameter for which nanowires show a similar phase transformation behavior to the bulk alloy is experimentally determined to lie between 280nm and 750nm.
Modeling Smart Materials Using Hysteretic Recurrent Neural Networks
Authors: Veeramani Arun , Crews John , Buckner Gregory D.
Published: February 2010

This paper describes a novel approach to modeling hysteresis using a Hysteretic Recurrent Neural Network (HRNN). The HRNN utilizes weighted recurrent neurons, each composed of conjoined sigmoid activation functions to capture the directional dependencies typical of hysteretic smart materials (piezoelectrics, ferromagnetic, shape memory alloys, etc.) Network weights are included on the output layer to facilitate training and provide statistical model information such as phase fraction probabilities. This paper demonstrates HRNN-based modeling of two- and three-phase transformations in hysteretic materials (shape memory alloys) with experimental validation. A two-phase network is constructed to model the displacement characteristics of a shape memory alloy (SMA) wire under constant stress. To capture the more general thermo-mechanical behavior of SMAs, a three-phase HRNN model (which accounts for detwinned Martensite, twinned Martensite, and Austensite phases) is developed and experimentally validated. The HRNN modeling approach described in this paper readily lends itself to other hysteretic materials and may be used for developing real-time control algorithms.
CASCADE PROCESS MODELING WITH MECHANISM-BASED HIERARCHICAL NEURAL NETWORKS
Authors: CONG QIUMEI , YU WEN , CHAI TIANYOU
Published: February 2010

Cascade process, such as wastewater treatment plant, includes many nonlinear sub-systems and many variables. When the number of sub-systems is big, the input-output relation in the first block and the last block cannot represent the whole process. In this paper we use two techniques to overcome the above problem. Firstly we propose a new neural model: hierarchical neural networks to identify the cascade process; then we use serial structural mechanism model based on the physical equations to connect with neural model. A stable learning algorithm and theoretical analysis are given. Finally, this method is used to model a wastewater treatment plant. Real operational data of wastewater treatment plant is applied to illustrate the modeling approach.
ENERGY CONTENTS OF GRAVITATIONAL WAVES IN TELEPARALLEL GRAVITY
Authors: SHARIF M. , TAJ SUMAIRA
Published: February 2010

The conserved quantities, that are, gravitational energy–momentum and its relevant quantities are investigated for cylindrical and spherical gravitational waves in the framework of teleparallel equivalent of General Relativity using the Hamiltonian approach. For both cylindrical and spherical gravitational waves, we obtain definite energy and constant momentum. The constant momentum shows consistency with the results available in General Relativity and teleparallel gravity. The angular momentum for cylindrical and spherical gravitational waves also turn out to be constant. Further, we evaluate their gravitational energy–momentum fluxes and gravitational pressure.
CALCULATION OF ENTROPY FOR SOME COUPLED OSCILLATORS BY USING THE GENERALIZED HELLMANN–FEYNMAN THEOREM
Authors: FAN HONG-YI , XU XUE-XIANG , HU LI-YUN
Published: February 2010

The entropies of several typical coupled bosonic oscillators are calculated by virtue of the generalized Hellmann–Feynman theorem (GHFT). The relation between GHFT and entropy-variation is construct by using von Neumann entropy, which provides us with a new approach for deriving entropy of some complicated systems.
DATABASE CLASSIFICATION BY INTEGRATING A CASE-BASED REASONING AND SUPPORT VECTOR MACHINE FOR INDUCTION
Authors: WANG YEN-WEN , CHANG PEI-CHANN , FAN CHIN-YUAN , HUANG CHIUNG-HUA
Published: February 2010

Database classification suffers from two common problems, i.e., the high dimensionality and nonstationary variations within the large historic data. This paper presents a hybrid classification model by integrating a case-based reasoning technique, a Support Vector Machine (SVM), and Genetic Algorithms to construct a decision-making system for data classification in various database applications. The model is mainly based on the concept that the historic database can be transformed into a smaller case-base together with a group of SVM models. As a result, the model can more accurately respond to the current data under classifying from the inductions by these SVM models generated from these smaller case bases. Hit rate is applied as a performance measure and the effectiveness of our proposed model is demonstrated by experimentally compared with other approaches on different database classification applications. The average hit rate of our proposed model is the highest among others.
INFLUENCE OF HELIUM SURFACE ON PHOTODETACHMENT OF NEGATIVE IONS
Authors: YANG GUANGCAN , YANG NINGYU , RUI KUIKUI
Published: February 2010

The photodetachment of H - on the surface of helium is investigated by quantum and semiclassical Green function approaches. It is found that a new sinusoidal oscillation is introduced in the photodetachment cross-section because of the existence of helium surface. Both quantum and semiclassical approaches give similar results but with minor difference when the photon energy is higher than the surface potential. The new oscillation is formed due to transmissions and reflections of the photodetached electronic waves on helium surface. It provides a simple system to test quantum reflection.
NANOCOMPOSITE Al2O3–Y2O3 FILMS ON CARBON STEEL
Authors: LI FANG , YAO MINGMING , PENG XUELEI
Published: February 2010

The nanocomposite Al 2 O 3– Y 2 O 3 films were prepared on the surface of carbon steel by an electrochemical process and a sintering process. High-resolution field emission scanning electron microscopy (FE-SEM) and X-ray photoelectron spectroscopy (XPS) were used to characterize the films, indicating that the films have nanostructures and the deposited alumina layers have a composition close to the stoichiometry of Al 2 O 3. SEM and mass gain measurement are adopted to study the oxidation resistance of films on carbon steel. It is proved that this kind of film is effective in protecting the substrate from oxidation. The mechanisms accounting for such effects have been discussed.
Very Low Ohmic Contact Resistance through an AlGaN Etch-Stop in Nitrogen-Polar GaN-Based High Electron Mobility Transistors
Authors: Brown Nidhi , Keller Stacia , Mishra Umesh K.
Published: February 2010

Ultra-low ohmic contact resistance of 0.1 Ω mm has been obtained as a step towards a deep-recess structure using N-polar GaN-based high electron mobility transistors (HEMTs). An AlGaN etchstop layer was investigated to obtain smooth and reliable gate recess. However due to reverse polarization, AlGaN results in a polarization-induced Schottky barrier which prevents ohmic contact to the channel through the etchstop. In this work, we have proposed a novel methodology to contact the two-dimensional electron gas (2DEG) by etching through the GaN cap and the AlGaN etchstop to eliminate the barrier and angular-evaporation of metals to achieve side-alloying resulting in very low ohmic contact resistance of 0.1 Ω mm achieved to N-polar GaN 2DEG. This result is state-of-the-art for alloyed contacts achieved to GaN-based 2DEG.
Comparison of Power Density Characteristics among Disk and Plate Shaped Piezoelectric Devices
Authors: Ural Seyit O. , Zhuang Yuan , Tuncdemir Safakcan , Uchino Kenji
Published: February 2010

High power density piezoelectric devices are required for smaller actuators and transformers. These devices are expected to perform similar to, or better than their larger scaled counterparts. Despite the superiority over their electromagnetic conjugates, piezoelectric devices are still limited in the amount of power they can handle. Commercial materials can carry vibration velocities up to 0.5 m/s (measured for a rectangular plate), which translates roughly into 25 W/cm3 power density. In this work, we examined the effect of shape and aspect ratio to the power density of two common actuator shapes, k
31 type rectangular plates and k

p
type disks. Results demonstrate that the power density of disks can be an order of magnitude higher than plates. While the power density is 10 times higher, the equivalent resistance of a disk shaped resonator is 10 times lower, making it a better candidate to match low output impedances, needed for high power transformers. Disks also show higher mechanical quality factors when considering a fixed output power per volume as a criterion. The results of this study validate the use of disk shaped actuators for high power density applications including as transducers and step down transformers.
Double Photonic Quasi-Crystal Structure Effect on GaN-Based Vertical-Injection Light-Emitting Diodes
Authors: Huang Hung-Wen , Lin Chung-Hsiang , Huang Zhi-Kai , Lee Kang-Yuan , Yu Chang-Chin , Kuo Hao-Chung
Published: February 2010

GaN-based thin-film vertical-injection light-emitting diodes (VLEDs) with a double 12-fold photonic quasi-crystal (PQC) structure formed using nanoimprint lithography (NIL) and inductively coupled plasma reactive-ion etching (ICP-RIE) are fabricated and presented. At a driving current of 20 mA and with a chip size of 350 ×350 µm2, our thin-film LED with a double-12-fold-PQC structure gave a light output power of 40.5 mW, which is an increase of 77% when compared with the output power of a VLED without a PQC structure at a peak wavelength of 460 nm. In addition, the corresponding light radiation patterns show a narrow beam shape due to the strong guided light extraction on the n-GaN surface and the reflected light effect of the PQC structure formed in the vertical direction on the p-GaN surface.
Fast Computational Integral Imaging Reconstruction Method Using a Fractional Delay Filter
Authors: Yoo Hoon , Shin Dong-Hak
Published: February 2010

In this paper, we propose a fast method for computational integral imaging reconstruction (CIIR) in computational integral imaging (CInIm). The previous CIIR method requires a very high computational cost to reconstruct a volumetric image from elemental images. To overcome this problem, we introduce a fast technique that reduces the computational cost markedly in comparison with the previous method. The proposed method employs a fractional delay (FD) filter in place of the magnification of elemental images. Then, the FD-filtered elemental images are superimposed on each other. We calculate the numbers of pixels that are considered in our CIIR method and in the previous one. On the basis of this, the proposed method can be a fast process because the number of pixels from our method is much less than that of pixels from the previous one. To show the usefulness of the proposed method, we carry out preliminary experiments and present the results in terms of computational cost and visual quality.
Design of Broadband Visible or Near-Infrared Antireflection Coating Based on Vibrating Search Approach
Authors: Liou Yeuh-Yeong , Huang Wen-Ben , Wang Shau-Kuei , Liu Wen-Long , Jaing Cheng-Chung
Published: February 2010

In this study, we present a numerical design approach, based on a vibrating search algorithm, to design a very low-loss normal-incidence broadband visible (vis) or near-infrared (NIR) antireflection (AR) coating. The vibrating search method involves the vibration adjustment and vibration-eliminating operations, which are utilized successively to improve the AR performance and simplify the design structure. Not only is the design algorithm very simple, the resultant broadband AR performance is also relatively good. The mean spectral reflectances of the AR coating designs in the visible region, 400–750 nm, and in the NIR region, 800–1600 nm, for a two-material multilayer system and obtained by the vibrating search method, can be reduced below 0.040 and 0.064%, respectively.
Optimal Charge of a Photocathode Gun for a Compact X-ray Free-Electron Laser
Authors: Lee Tae-Yeon , Chae Moon Sik , Ko In Soo
Published: February 2010

For a photocathode gun, the optimal charge per gun pulse is derived to give the theoretically allowed smallest saturation length of the X-ray free-electron laser based on the self amplified spontaneous emission scheme. The derivation is approximate, but the result is practically independent of specific machine design. The objective is to contribute to the study of a compact X-ray free-electron laser.
Domain Wall Dynamics under an In-Plane Rotating Magnetic Field in a Nanowire with Perpendicular Magnetic Anisotropy
Authors: Lee Sung Chul , Cho Young Jin , Pi Ung Hwan , Bae Ji Young , Heo Jinseong , Seo Sunae , Shin Jae Kwang , Lee Taek Dong
Published: February 2010

As an alternative to current or static magnetic field driven domain wall (DW) motion, we studied the dynamics of DW motion under an in-plane rotating magnetic field (IRMF) in a metallic nanowire with a perpendicular magnetic anisotropy. An equation describing the DW motion was obtained with a one-dimensional analytical model based on a collective coordinate approach. The DW velocity can easily be controlled up to hundreds of meters per second by varying the IRMF amplitude and frequency. The validity of the equation for DW motion was confirmed with micromagnetic simulations.
Single-Phase Drive Linear Ultrasonic Motor with Perpendicular Electrode Vibrator
Authors: Hsiao Shih-Wei , Tsai Mi-Ching
Published: February 2010

Unlike most ultrasonic motor designs, in this study, we employ a pair of perpendicular electrodes to energize a piezoelectric vibrator, in which the angle between the direction of polarization and the electric field is purposely set at neither 0 nor 90° so that both the longitudinal and shear effects of the vibrator can be generated simultaneously by a single-phase voltage source. Such a vibrator can generate oblique line trajectories on the contact surface to push a slider for movement, while its moving direction can be easily controlled by switching the excitation sequence of the pair of perpendicular electrodes. In this study, the finite element analysis method was first employed to simulate the oscillatory behavior of the vibrator and then simulation results were verified by single-point, noncontact measurement on the surface of the vibrator. The newly designed linear ultrasonic motor, which can offer identical performance in both forward and backward motions, can maintain its attractive characteristics of simple structure, quiet operation, and single-phase drive. A prototype of the single-phase drive linear ultrasonic motor was fabricated to confirm the feasibility of the proposed vibrator design. The illustrated bidirectional linear ultrasonic motor is shown to be capable of generating a sliding velocity of 84.2 mm/s and a sliding force of 1.79 N.
Dual-Gate Field-Effect Transistor Hydrogen Gas Sensor with Thermal Compensation
Authors: Tsukada Keiji , Kariya Masatoshi , Yamaguchi Tomiharu , Kiwa Toshihiko , Yamada Hironobu , Maehara Tsuneyoshi , Yamamoto Tadayoshi , Kunitsugu Shinsuke
Published: February 2010

We developed a dual-gate field-effect transistor (FET) hydrogen gas sensor for application to hydrogen vehicles. The dual-gate FET hydrogen sensor was integrated with a Pt-gate FET to detect hydrogen and a Ti-gate FET as the reference sensor in the same Si chip. The Ti-FET had the same structure as the Pt-FET except for the gate metal. The Pt-FET showed a good response to hydrogen gas above 10 ppm in air, while the Ti-FET did not show any response to hydrogen gas. The differential output voltage between the Pt-FET and the Ti-FET was stable in the temperature range from room temperature to 80 °C because of the same temperature dependence of the current–voltage (I–V) characteristics. In addition, the temperature of the integrated hydrogen sensor was controlled by an integrated system consisting of a heater and a thermometer at any given temperature under severe weather conditions.
Numerical Analysis of Vacancy Transport by Residual Stress in Electromigration on LSI Interconnects
Authors: Nemoto Takenao , Jr. Toshimitsu A. Yokobori, , Murakawa Tsutomu , Miura Hideo
Published: February 2010

The Li multiplication method for the driving force induced particle migration equation was proposed to solve numerically the stress and electric fields induced vacancy migration equation. On the basis of this method, vacancy migration behaviors were found to be predicted under the competitive relationship between stress and electric field. When a residual stress is dominant, vacancies concentrate around the maximum hydrostatic stress region, such as elastic–plastic boundary. On the other hand, when the electric field is dominant, vacancies do not concentrate around the maximum hydrostatic stress region, but move from the cathode end to the anode end. An in situ observation of electromigration on AlCuSi interconnect was conducted to verify the simulation results. A void nucleated and grew at the tip of a notch on an AlCuSi line without passivation film, while many voids appeared and grew in cathode side in a line with passivation film. Greater hydrostatic stress gradient is considered to occur in the line without passivation film, owing to a small scale of yielding, and this leads to concentrate void formation at the tip of the notch. These results indicate that numerical analysis of electromigration is valid to represent the experimental result. Based on results mentioned above, various failure modes in interconnects cased by electromigration are predictable by the proposed Li multiplication method.
Multilayered Three-Dimensional Structures of Ag Nanoparticles in Anodic Porous Alumina
Authors: Kondo Toshiaki , Nishio Kazuyuki , Masuda Hideki
Published: February 2010

Multilayered three-dimensional (3D) structures composed of orderly arranged Ag nanoparticles in an anodic alumina matrix were fabricated. The repeated anodization of Al and the subsequent electrochemical deposition of Ag generated the multilayered structure of Ag nanoparticles. The size of the gaps between Ag particles could be controlled precisely by changing the anodization time after the electrochemical deposition of Ag. The obtained 3D composites exhibited characteristic optical properties originating from the localized surface plasmon (LSP) of the Ag nanoparticles.
Comparison of Surface Modifications by Wet and Dry Methods on Indium Tin Oxide Using Self-Assembled Monolayers
Authors: Jee Seung Hyun , Kim Soo Ho , Park Hoon , Kim Dong-Joo , Yoon Young Soo
Published: February 2010

We developed a self-assembled monolayer (SAM) surface modification of an indium tin oxide (ITO; SnO2–In2O3) by a dry method for ink-jet printing processes and compared this with the SAM surface modifications by wet and dry methods. We focused on an analysis of the work function increase and changes in chemical bonding at the ITO surface interface with the SAM. In addition, we demonstrated that the causes of the work function increase of the ITO were the binding energy changes of the oxygen atoms on the ITO surface and an improvement in the hole injection from the ITO with the SAM to an organic layer in the organic device. The SAM surface modification decreased the threshold voltage and increased the current density in the organic device. These changes were due to the energy barrier caused by the work function difference being removed at the interface between the ITO with a high work function (5.3 to 5.5 eV) and the organic layer. Additionally, it was observed that the current density and luminance characteristics of the device were improved by the SAM surface modification. There was less organic solvent contamination at the interface between the ITO and the SAM by the dry method because no organic solvent was used.
Switching Characteristics of Silica Nanoparticle-Doped Dual-Mode Liquid Crystal Device
Authors: Huang Chi-Yen , Lai Chien-Cheng , Huang Yi-Jen , Chen Jian-Hong
Published: February 2010

We investigate the switching characteristics of a silica nanoparticle-doped dual-mode liquid crystal (LC) display. In the multistable mode, aggregated silica networks impede the relaxation of LCs and increase the response time of the cell. A low-frequency AC pulse voltage rotates LCs and breaks aggregated silica networks. The breaking of silica networks accelerates the relaxation of LCs and hence decreases the response time of the cell. The low-frequency AC pulse voltage gives the cell a fast response time of ∼23 ms, which is ∼4% of our previous result.
Constant-Pressure Molecular-Dynamics Study of Carbon Nanotubes and Electronic Structure of New Phases
Authors: Sakurai Masahiro , Saito Susumu
Published: February 2010

The pressure-induced structural phase transition of carbon nanotubes is studied using the constant-pressure tight-binding molecular-dynamics method. We find that an interesting sp2–sp3 hybrid structure, which is considered as a graphitic nanoribbon solid, is obtained from the nanotube solid composed of armchair nanotubes. The sp3-rich phase with anisotropic atomic network is also obtained at elevated pressure and is predicted to have high hardness which is comparable to that of cubic diamond. In contrast, the bundle composed of both armchair and chiral nanotubes transforms into amorphous diamond phase at high pressure. From the electronic-structure study in the framework of the density-functional theory, the nanoribbon solid phase obtained is found to be metallic.
Surface Potential Investigation of Carbon Nanotube Field-Effect Transistor by Point-by-Point Atomic Force Microscope Potentiometry
Authors: Miyato Yuji , Kobayashi Kei , Matsushige Kazumi , Yamada Hirofumi
Published: February 2010

We measured the local surface potential of a carbon nanotube field-effect transistor (CN-FET) by atomic force microscope potentiometry using the point-by-point contact method. When a bias voltage was applied to the nanotube, local variation in the surface potential reflecting the relative Fermi level was measured along the nanotube. Moreover, we observed that the potential barrier height at the source contact was changed upon application of positive gate voltages. This result suggests that the field-effect in the measured CN-FET was caused by modulation of the Schottky barrier at the source contact.
Photocurrents in Carbon Nanotubes with Various Diameters under High-Intensity Laser Irradiation
Authors: Konabe Satoru , Yamamoto Takahiro , Watanabe Kazuyuki
Published: February 2010

The photocurrents of carbon nanotubes (CNTs) under high-intensity laser irradiation are studied theoretically. Photocurrents of E
11 excitons dissociated by the Auger recombination process are calculated for zigzag CNTs with various diameters. The photocurrents due to dissociated excitons emerge at the threshold laser-intensity and the threshold decreases as the CNT diameters increase. Furthermore, the photocurrents become larger for larger diameter CNTs.
Electric and Mass Transport of a Suspended Multiwall Carbon Nanotube Studied by In situ Transmission Electron Microscopy
Authors: Suzuki Yasunobu , Asaka Koji , Nakahara Hitoshi , Saito Yahachi
Published: February 2010

A single multiwall carbon nanotube was bridged between platinum and indium–gallium (In–Ga) alloy electrodes in a transmission electron microscope, and electric resistances between the electrodes at various bridge lengths were measured in situ with the imaging of the structural dynamics of the nanotube. The intrinsic resistivity of the nanotube and the contact resistances between the nanotube and the electrodes were analyzed, and the resistivity of the nanotube was estimated to be 3.8 ×10-4 Ω cm. At a high current exceeding about 120 µA with the In–Ga alloy electrode being positively biased, the alloy material migrated along the nanotube surface toward the counter electrode.
Defective Carbon Nanotube for Use as a Thermal Rectifier
Authors: Takahashi Koji , Inoue Masato , Ito Yohei
Published: February 2010

We investigated the thermal properties of a single-walled carbon nanotube with vacancy defects to determine its applicability to solid-state thermal rectification. Nonequilibrium molecular dynamics simulation of a nanotube with randomly located defects only along half the length revealed asymmetric heat conduction at room temperature. The direction of rectification is in good agreement with that obtained in a past experiment in which C9H16Pt was asymmetrically deposited on a nanotube, as far as the local deposition is supposed to cause defects in the nanotube lattice. The mechanism underlying the current thermal rectification effect is discussed considering the temperature dependence of the local thermal conductivity and the phonon filtering effect. The calculated phonon density of states shows larger overlapping when heat flows from the defective part to the pristine part and intermediate-frequency phonons are mainly responsible for rectification.
Detection of extracellular glucose by GLUT2 contributes to hypothalamic control of food intake
Authors: Stolarczyk Emilie , Guissard Christophe , Michau Aurélien , Even Patrick C. , Grosfeld Alexandra , Serradas Patricia , Lorsignol Anne , Pénicaud Luc , Brot-Laroche Edith , Leturque Armelle , Le Gall Maude
Published: February 2010

The sugar transporter GLUT2, present in several tissues of the gut-brain axis, has been reported to be involved in the control of food intake. GLUT2 is a sugar transporter sustaining energy production in the cell, but it can also function as a receptor for extracellular glucose. A glucose-signaling pathway is indeed triggered, independently of glucose metabolism, through its large cytoplasmic loop domain. However, the contribution of the receptor function over the transporter function of GLUT2 in the control of food intake remains to be determined. Thus, we generated transgenic mice that express a GLUT2-loop domain, blocking the detection of glucose but leaving GLUT2-dependent glucose transport unaffected. Inhibiting GLUT2-mediated glucose detection augmented daily food intake by a mechanism that increased the meal size but not the number of meals. Peripheral hormones (ghrelin, insulin, leptin) were unaffected, leading to a focus on central aspects of feeding behavior. We found defects in c-Fos activation by glucose in the arcuate nucleus and changes in the amounts of TRH and orexin neuropeptide mRNA, which are relevant to poorly controlled meal size. Our data provide evidence that glucose detection by GLUT2 contributes to the control of food intake by the hypothalamus. The sugar transporter receptor, i.e., “transceptor” GLUT2, may constitute a drug target to treat eating disorders and associated metabolic diseases, particularly by modulating its receptor function without affecting vital sugar provision by its transporter function.
The Effect of Calcipotriol on the Expression of HumanβDefensin-2 and LL-37 in Cultured Human Keratinocytes
Authors: Kim Beom Joon , Rho Yong Kwan , Lee Hye In , Jeong Mi Sook , Li Kapsok , Seo Seong Jun , Kim Myeung Nam , Hong Chang Kwun
Published: February 2010

Background. Vitamin D has been reported to regulate innate immunity by controlling the expression of antimicrobial peptides (AMPs).Objective. We investigated the effect of calcipotriol on the expression of AMPs in human cultured keratinocytes.Methods. Keratinocytes were treated with lipopolysaccharide (LPS), TNF-α, Calcipotriol and irradiated with UVB, cultured, and harvested. To assess the expression of human beta defensin-2 and LL-37 in the control group, not exposed to any stimulants, the experimental group was treated with LPS, TNF-α, or UVB, and another group was treated again with calcipotriol; reverse transcriptase-polymerase chain reaction, Western blotting, and immunohistochemical staining were performed.Results. In the experimental group treated with LPS, UVB irradiation, and TNF-α, the expression ofβ-defensin and LL-37 was increased more than in the control group and then decreased in the experimental group treated with calcipotriol.Conclusions. Calcipotriol suppressed HBD-2 and LL-37, which were stimulated by UVB, LPS, and TNF-α.
Tree Mortality following Prescribed Fire and a Storm Surge Event in Slash Pine (Pinus elliottiivar.densa) Forests in the Florida Keys, USA
Authors: Sah Jay P. , Ross Michael S. , Snyder James R. , Ogurcak Danielle E.
Published: February 2010

In fire-dependent forests, managers are interested in predicting the consequences of prescribed burning on postfire tree mortality. We examined the effects of prescribed fire on tree mortality in Florida Keys pine forests, using a factorial design with understory type, season, and year of burn as factors. We also used logistic regression to model the effects of burn season, fire severity, and tree dimensions on individual tree mortality. Despite limited statistical power due to problems in carrying out the full suite of planned experimental burns, associations with tree and fire variables were observed. Post-fire pine tree mortality was negatively correlated with tree size and positively correlated with char height and percent crown scorch. Unlike post-fire mortality, tree mortality associated with storm surge from Hurricane Wilma was greater in the large size classes. Due to their influence on population structure and fuel dynamics, the size-selective mortality patterns following fire and storm surge have practical importance for using fire as a management tool in Florida Keys pinelands in the future, particularly when the threats to their continued existence from tropical storms and sea level rise are expected to increase.
Strong Convergence Theorems for Equilibrium Problems and Fixed Point Problems in Hilbert Spaces
Authors: Peng Jian-Wen , Wang Yan
Published: February 2010

We introduce an Ishikawa iterative scheme by the viscosity approximate method for finding a common element of the set of solutions of an equilibrium problem and the set of fixed points of a nonexpansive mapping in Hilbert space. Then, we prove some strong convergence theorems which extend and generalize S. Takahashi and W. Takahashi′s results (2007).
A Novel Negative Fe-Deficiency-Responsive Element and a TGGCA-Type-Like FeRE Control the Expression ofFTR1inChlamydomonas reinhardtii
Authors: Fei Xiaowen , Eriksson Mats , Li Yajun , Deng Xiaodong
Published: February 2010

We have reported three Fe-deficiency-responsive elements (FEREs),FOX1, ATX1,andFEA1, all of which are positive regulatory elements in response to iron deficiency inChlamydomonas reinhardtii. Here we describeFTR1, another iron regulated gene and mutational analysis of its promoter. Our results reveal that the FeREs ofFTR1distinguish itself from other iron response elements by containing bothnegativeandpositiveregulatory regions. InFTR1, the−291/−236 region from the transcriptional start site is necessary and sufficient for Fe-deficiency-inducible expression. This region contains two positive FeREs with a TGGCA-like core sequence: the FtrFeRE1 (ATGCAGGCT) at−287/−279 and the FtrFeRE2 (AAGCGATTGCCAGAGCGC) at−253/−236. Furthermore, we identified a novel FERE, FtrFeRE3 (AGTAACTGTTAAGCC) localized at−319/−292, which negatively influences the expression ofFTR1.
Protein Kinase Cι Is Required for Pancreatic Cancer Cell Transformed Growth and Tumorigenesis
Authors: Scotti Michele L. , Bamlet William R. , Smyrk Thomas C. , Fields Alan P. , Murray Nicole R.
Published: February 2010

Pancreatic cancer is the fourth leading cause of cancer deaths in the United States, with an overall 5-year survival rate of <5%. Pancreatic ductal adenocarcinoma (PDAC), the most common form of pancreatic cancer, is highly resistant to conventional chemotherapies, underscoring the critical need for new molecular targets for pancreatic cancer chemotherapy. The KRAS proto-oncogene is mutated in >90% of PDAC. Protein kinase Cι (PKCι) is required for the oncogenic Ras–mediated transformed growth of lung cancer and intestinal epithelial cells. However, little is known about the role of PKCι in pancreatic cancer. In this study, we evaluated the expression of PKCι in human pancreatic cancer and the requirement for PKCι for the transformed growth and tumorigenicity of PDAC cells. We find that PKCι is significantly overexpressed in human pancreatic cancer, and high PKCι expression correlates with poor patient survival. Inhibition of PKCι expression blocks PDAC cell transformed growth in vitro and tumorigenicity in vivo. Inhibition of PKCι expression in pancreatic tumors also significantly reduces tumor angiogenesis and metastasis. Analysis of downstream PKCι effectors implicates the Rac1-MEK/ERK1/2 signaling axis in PKCι-mediated transformed growth and cellular invasion. Taken together, our data show a required role for PKCι in the transformed growth of pancreatic cancer cells and reveal a novel role for PKCι in pancreatic cancer cell metastasis and angiogenesis in vivo. Our results strongly indicate that PKCι will be an effective target for pancreatic cancer therapy. Cancer Res; 70(5); 2064–74
The First-in-Human Study of the Hydrogen Sulfate (Hyd-Sulfate) Capsule of the MEK1/2 Inhibitor AZD6244 (ARRY-142886): A Phase I Open-Label Multicenter Trial in Patients with Advanced Cancer
Authors: Banerji Udai , Camidge D. Ross , Verheul Henk M.W. , Agarwal Roshan , Sarker Debashis , Kaye Stan B. , Desar Ingrid M.E. , Timmer-Bonte Johanna N.H. , Eckhardt S. Gail , Lewis Karl D. , Brown Kathryn H. , Cantarini Mireille V. , Morris Clive , George Sarah M.A. , Smith Paul D. , van Herpen Carla M.L.
Published: February 2010

Purpose: In part A, the aim was to define the maximum tolerated dose (MTD) of the hydrogen sulfate (Hyd-Sulfate) oral capsule formulation of the mitogen-activated protein kinase kinase inhibitor AZD6244 (ARRY-142886). In part B, the aim was to compare the pharmacokinetic profile of the new Hyd-Sulfate capsule with the initial AZD6244 free-base suspension and further characterize the pharmacodynamic profile and efficacy of the new formulation.

Experimental Design: In part A, 30 patients received escalating doses of AZD6244 Hyd-Sulfate twice daily. In part B, 29 patients were randomized to a single dose of the Hyd-Sulfate capsule or free-base suspension, followed by a washout, then a single dose of the alternative formulation. Patients received the Hyd-Sulfate capsule twice daily at MTD of part A thereafter.

Results: The MTD of the Hyd-Sulfate capsule was 75 mg twice daily. Dose limiting toxicities were Common Terminology Criteria for Adverse Events grade 3 acneiform rash and pleural effusion. Fatigue (65.7%) and acneiform dermatitis (60.0%) were the most frequent adverse events at the MTD. Based on area under curve0-24, exposure of the 75 mg Hyd-Sulfate capsule relative to the 100 mg free-base suspension was 197% (90% confidence interval, 161-242%). Pharmacodynamic analysis showed that inhibition of 12-O-tetradecanoylphorbol-13-acetate–induced extracellular signal-regulated kinase phosphorylation in peripheral blood lymphocytes was related to plasma concentrations of AZD6244, with an estimated IC50 of 352 ng/mL and maximum inhibition (Emax) of ∼91%, showing target inhibition. A patient with metastatic melanoma bearing a V600E BRAF mutation achieved a complete response persisting after 15 months of therapy.

Conclusions: The AZD6244 Hyd-Sulfate capsule formulation has shown a favorable toxicity, pharmacokinetic, and pharmacodynamic profile, and is being taken forward in ongoing clinical trials. Clin Cancer Res; 16(5); 1613–23
Nonsense-Mediated RNA Decay Regulation by Cellular Stress: Implications for Tumorigenesis
Authors: Gardner Lawrence B.
Published: February 2010

Nonsense-mediated RNA decay (NMD) has long been viewed as an important constitutive mechanism to rapidly eliminate mutated mRNAs. More recently, it has been appreciated that NMD also degrades multiple nonmutated transcripts and that NMD can be regulated by wide variety of cellular stresses. Many of the stresses that inhibit NMD, including cellular hypoxia and amino acid deprivation, are experienced in cells exposed to hostile microenvironments, and several NMD-targeted transcripts promote cellular adaptation in response to these environmental stresses. Because adaptation to the microenvironment is crucial in tumorigenesis, and because NMD targets many mutated tumor suppressor gene transcripts, the regulation of NMD may have particularly important implications in cancer. This review briefly outlines the mechanisms by which transcripts are identified and targeted by NMD and reviews the evidence showing that NMD is a regulated process that can dynamically alter gene expression. Although much of the focus in NMD research has been in identifying the proteins that play a role in NMD and identifying NMD-targeted transcripts, recent data about the potential functional significance of NMD regulation, including the stabilization of alternatively spliced mRNA isoforms, the validation of mRNAs as bona fide NMD targets, and the role of NMD in tumorigenesis, are explored. Mol Cancer Res; 8(3); 295–308
The Trauma of Truth Telling: Effects of Witnessing in the Rwandan Gacaca Courts on Psychological Health
Authors: Brounéus Karen
Published: February 2010

Truth telling has come to play a pivotal role in postconflict reconciliation processes around the world. A common claim is that truth telling is healing and will lead to reconciliation. The present study applies recent psychological research to this issue by examining whether witnessing in the gacaca, the Rwandan village tribunals for truth and reconciliation after the 1994 genocide, was beneficial for psychological health. The results from the multistage, stratified cluster random survey of 1,200 Rwandans demonstrate that gacaca witnesses suffer from higher levels of depression and PTSD than do nonwitnesses, also when controlling for important predictors of psychological ill health. Furthermore, longer exposure to truth telling has not lowered the levels of psychological ill health, nor has the prevalence of depression and PTSD decreased over time. This study strongly challenges the claim that truth telling is healing and presents a novel understanding of the complexity of truth-telling processes in postconflict peace building.
An Exploratory Study of the Characteristics of Men Known to Commit Prisoner-on-Prisoner Sexual Violence
Authors: Morash Merry , Seok Jin Jeong  , Zang Nancy L.
Published: February 2010

For one state correctional system, 1998 through 2006, 121 perpetrators were compared with 121 nonperpetrators. Sexual abuse victimization as a child, a life sentence, and adult sexual assault convictions predicted men’s unwanted sexual touching of other men. History of juvenile robbery and adult sexual assault convictions, more years in prison, and youth characterized men who threatened, attempted, or achieved sexual penetration with another inmate. Individual predispositions appear to be relevant to understanding prison sexual violence and should be examined along with contextual influences. Findings suggest needed areas of future research and have implications for preventing sexual violence in prisons.