bluuebunny/crossref_metadata_2025 huggingface dataset:
Integration of Microcoil Magnetic Manipulation with High-Sensitivity Complementary Metal–Oxide–Semiconductor Photosensor Detection in Bio-Analyses
Authors: Chen Chih-Yang , Lin Chrong-Jung , King Ya-Chin
Published: April 2010

In this paper, an integration design including a microcoil device and a photodetector with analog-pulse output is proposed for the real-time control and monitoring of magnetic samples or beads of micrometer size. The microcoil array consisting of top metal layers in complementary metal–oxide–semiconductor (CMOS) integrated circuits can successfully manipulate and anchor the magnetic beads by a maximum of 9 G of electromagnetic field when driven by 10 mA. In addition, real-time detection of the location and size of the manipulated samples are demonstrated with an integrated pulse-frequency-modulation (PFM) photosensor array. On the basis of the light intensity received on the sensor plane underneath the microcoils, a bioreaction-induced self-luminance process with a minimal illumination of 5.77×10-5W/m2can be successfully identified. This integrated array realized by the CMOS process offers both manipulation and monitoring functions simultaneously, which allows for easier and low-cost parallel bioassay analysis on a single chip.
Actuation of Magnetic Beads on a Complementary Metal–Oxide–Semiconductor Chip for Biological Applications
Authors: Ishikawa Tomohiro , Kaneko Fumie , Johguchi Koh
Published: April 2010

Magnetic beads with a diameter of 2.8 µm are actuated on a standard complementary metal–oxide–semiconductor (CMOS) chip. The chip was fabricated using the 180 nm process and has two groups of parallel current paths in the top metal layer and the second top metal layer. These two are placed diagonally to each other. Suspended beads were applied onto the chip and a magnetic field that was induced by patterned currents manipulated beads successfully. To observe an effect induced by a thermal convection flow, several current patterns were tested and the actuation of beads was examined. The result suggests that the beads were mainly driven by the magnetic field and partially affected by a convex flow generated by the current on the paths.
Differential Light Addressable Potentiometric Sensor with Poly(vinyl chloride) and HfO2 Membranes for pH Sensors
Authors: Lue Cheng-En , Lai Chao-Sung , Wang Jer-Chyi , Wu Ching-Mie , Yang Chia-Ming
Published: April 2010

In this paper, a differential measurement setup for the light addressable potentiometric sensor (LAPS) is proposed. The LAPS with a HfO2 layer as the sensing membrane was used, and different weight percentages of DNP/(PVC+DNP) [DNP: dinonylphtalate, PVC: poly(vinyl chloride)] membrane were cast on the surface of HfO2-LAPS. The pH sensitivity can be decreased from 58.6 to 24.5 mV/pH by using 60 wt % PVC cocktail. Then, the pH sensitivity measured through a differential circuit was 30.1 mV/pH, showing high potential for replacing the function of a conventional reference electrode as an ion-sensitive field-effect transistor (ISFET)/reference field-effect transistor (REFET) pair. In addition, to confirm the output signal of the two substrate electrodes, a specific measurement setup was used.
Design and Fabrication of Complementary Metal–Oxide–Semiconductor Sensor Chip for Electrochemical Measurement
Authors: Yamazaki Tomoyuki , Ikeda Takaaki , Kano Yoshiko , Takao Hidekuni , Ishida Makoto , Sawada Kazuaki
Published: April 2010

An electrochemical sensor has been developed on a single chip in which potentiostat and sensor electrodes are integrated. Sensor chips were fabricated using 5.0 µm complementary metal–oxide–semiconductor (CMOS) technology. All processes including the CMOS process, postprocessing for fabricating sensor electrodes and passivation layers, and packaging were performed at Toyohashi University of Technology. The integration makes it possible to measure electrochemical signals without having to use a bulky external electrochemical system. The potential between the working electrode and the reference electrode was controlled using an on-chip potentiostat composed of CMOS transistors. The chip characteristics were verified by electrochemical measurement, namely, by cyclic voltammetry. Potassium ferricyanide solution was measured to obtain results that fit well to the theoretical formula. A clear proportional relationship between peak height and the concentration of the sample solution was obtained using the proposed sensor chip, and the dynamic range obtained was 0.10 to 8.0 mM.
A Real-Time Monitoring System Using a Multimodal Sensor with an Electrical Conductivity Sensor and a Temperature Sensor for Cow Health Control
Authors: Futagawa Masato , Iwasaki Taichi , Ishida Mitsuyoshi , Kamado Keita , Ishida Makoto , Sawada Kazuaki
Published: April 2010

A multimodal sensor composed of an electrical conductivity (EC) sensor and a temperature sensor on the same Si chip was successfully fabricated using compatible complementary metal oxide semiconductor (CMOS) technology. The EC sensor measured the electrical conductivity between Pt electrodes, and the temperature sensor measured the forward voltage of a p–n junction diode. We confirmed the output signal in a wide dynamic range of ECs. For real-time measurement in the rumen of cows, a wireless system was fabricated. The system included a sensor, a battery, an antenna, an analog signal-processing circuit board, an AC-to-DC converter board, and a receiver–transmitter board. We adjusted the wireless system design with focus on the measurement range to adapt the system to the rumen. Real-time and simultaneous measurements of EC and temperature in the rumen using the multimodal sensor unit were performed. The wireless system successfully received signals continuously, and enabled the measurement of the rumen conditions in real time.
Radio Frequency Identification Sensor Chips with Anticollision Algorithm for Simultaneous Detection of Multiple DNA Targets
Authors: Yazawa Yoshiaki , Oonishi Tadashi , Watanabe Kazuki , Nemoto Ryo , Shiratori Akiko
Published: April 2010

A newly developed DNA measurement method for multiple single nucleotide polymorphism (SNP) typing using a radio-frequency identification (RFID) sensor chip was demonstrated. The RFID sensor chip monolithically integrates a sensor, amplifier, analog-to-digital converter (ADC), and a passive wireless communication interface for receiving commands and transmitting data on a 2.5×2.5 mm2 silicon chip. For the simultaneous multitarget measurement, anticollision control and peak-power suppression are essential. To assign a unique identification number (UID) for the identification of multiple sensor chips, a reproducible random number generator circuit (RRG) was designed and installed on the chip. Peak-power consumption was reduced to 1018 µW by a clock gating of functional circuit blocks. Multiple SNP typing was carried out by simultaneously operating five RFID sensor chips (four with photosensors and one with a temperature sensor). The target DNA was captured on the sensor chips, and SNPs were detected by observing bioluminescence. Finally, the observed data were wirelessly transmitted to the reader.
Multichannel Biosensing and Stimulation LSI Chip Using 0.18 µm Complementary Metal–Oxide–Semiconductor Technology
Authors: Yamaguchi Masaya , Shimada Akiyoshi , Torimitsu Keiichi , Nakano Nobuhiko
Published: April 2010

We designed 8-channel preamplifiers and multisite stimulation circuits on a 2.5 ×1.4 mm2 chip using a 0.18 µm complementary metal–oxide–semiconductor (CMOS) process for a microelectrode array measurement system. The size of a 1-channel preamplifier including a DC store/adder circuit is 930 ×120 µm2. An 8-channel programmable stimulator was integrated on the same die. The preamplifier circuits can amplify a small neural signal with a low noise and a low power consumption (2 mW/ch) using a chopper operation. The stimulation circuits can apply a voltage of ±700 mV to any channel and with any timing using serial digital data control. The performance of the biphasic stimulation waveform generated by the designed LSI chip is the same as that generated with a conventional stimulation system. These functions were confirmed by connecting the LSI chip to a conventional measurement system. The system miniaturization achieved using the custom LSI chip will offer great advantages in terms of future brain machine interface applications.
Self-Spreading Supported Lipid Bilayer Passing through Single Nanogap Structure: Effect of Position of Dyes in Lipid Molecules
Authors: Kashimura Yoshiaki , Furukawa Kazuaki , Torimitsu Keiichi
Published: April 2010

We report the self-spreading behavior of single lipid bilayers containing 7-nitrobenz-2-oxa-1,3-diazol-4-yl (NBD) fluorophores on a patterned surface equipped with a single nanogap. We found that the behavior of the fluorophores around the nanogap depended on the position of the dyes in the lipid molecules. For acyl chain-labeled lipids, the fluorescence intensities decreased discontinuously before and after they passed through the nanogap, whereas little decrease was observed for a headgroup-labeled lipid. A possible mechanism can be explained in terms of the reorientation of dyes in a lipid bilayer. Acyl chain-labeled NBD fluorophores are known to loop back to a lipid–water interface in a lipid bilayer. Since this effect makes an effective size of the lipid molecule larger, dye molecules easily suffer from steric hindrance when they pass through a nanogap leading to the fluorescence intensity reduction.
Novel Si Nanodisk Fabricated by Biotemplate and Defect-Free Neutral Beam Etching for Solar Cell Application
Authors: Huang Chi-Hsien , Igarashi Makoto , Horita Susumu , Takeguchi Masaki , Uraoka Yukiharu , Fuyuki Takashi , Yamashita Ichiro , Samukawa Seiji
Published: April 2010

We have already developed a uniform silicon-based two-dimensional quantum dot superlattice (2D QDSL) (i.e., 2D array of Si nanodisks) on the x–y plane with high-density nanodisks (NDs) and controllable size and spacing between NDs. To integrate more nanodisks in the third dimension (z-axis), a new stacked nanodisk (S-ND) has been developed by using thin film deposition, bio-template and advanced alternate etching. The S-ND structure comprises of two NDs connected vertically by coupling a tunnel junction (TJ). The scanning transmission electron microscopy image clearly revealed the stacked structure. The quantum confinement of S-ND was confirmed by observing the Coulomb staircase at room temperature. Tunneling current could be controlled by changing TJ thickness. By simply changing the ND thickness, band gap energy (E
g) could be controlled. These characteristics of the quantum effect and E
g play important roles in QDSL solar cells.
Contrast Enhancement of Wavelength-Selective Detection of Mid-Infrared Using Localized Atmospheric-Pressure Plasma Treatment
Authors: Masuno Katsuya , Tashiro Kohji , Hori Masaru , Kumagai Shinya , Sasaki Minoru
Published: April 2010

A new processing method to enhance the signal contrast of a mid-infrared (MIR) detector integrated with a wavelength-selective function is studied. Using the hydrophilic characteristic of an IR absorber solution, an absorber material is selectively deposited onto a hydrophilically modified area over the hot junctions in the diaphragm of a thermopile detector. The hydrophilic modification of the chip-mounted detector is realized using localized atmospheric Ar + O2plasma treatment through a stencil mask. Using a thermograph, we measured thermal distributions over a previously fabricated detector, whose absorber material is deposited using a manual manipulator without a position-selective mechanism, and the newly fabricated detector for comparison. The newly fabricated detector exhibited a larger temperature difference between hot and cold junctions than that of the previous detector. The detector has an increased signal contrast of 100% from the baseline at the absorption peak.
Novel Design for Optical Scanner with Piezoelectric Film Deposited by Metal Organic Chemical Vapor Deposition
Authors: Matsuo Hirokazu , Kawai Yusuke , Esashi Masayoshi
Published: April 2010

A two-dimensional (2D) optical micro mirror scanner with piezoelectric film deposited by metal organic chemical vapor deposition (MOCVD) was designed, fabricated, and evaluated. The overall area of the device is 2.5×2.5 mm2 and the mirror diameter is 1 mm. A small footprint device compared with the mirror size was realized. The piezoelectric film was deposited using a semi-homemade MOCVD apparatus. The device was fabricated by a micro fabrication technique with simple three mask processes. The optical scanning angles of torsional and bending rotations are, respectively, 17 and 16° at 20 Vp–p with a 1.6-µm-thick lead zirconate titanate (PZT) film and a 20-µm-thick Si structure in atmospheric ambient. The resonant frequencies of torsional rotation mode and bending rotation mode are, respectively, 15 and 10 kHz. The laser beam scanning of an unclosed Lissajous figure can scan all the pixel points on a 2D image frame within a certain time interval. The small 2D scanner is expected to be suitable for the mass production of portable optical devices.
Plasma-Induced Deterioration of Mechanical Characteristics of Microcantilever
Authors: Tomura Maju , Huang Chi-Hsien , Yoshida Yusuke , Ono Takahito , Yamasaki Satoshi , Samukawa Seiji
Published: April 2010

We investigated the effects of the defects generated by plasma in a silicon (Si) microcantilever. The E' center density of the microcantilever was markedly increased after argon (Ar) plasma irradiation. On the other hand, the E' center density could be effectively suppressed when using Ar neutral beam (NB). The mechanical characteristics, including theQfactor and resonant frequency, of a microcantilever were markedly decreased by plasma irradiation, which revealed that plasma irradiation deteriorated the mechanical characteristics of the micro element. These results have a considerable impact on micro- and nano-electro-mechanical systems (MEMSs/NEMSs). On the other hand, for NB irradiation, both characteristics were basically unchanged after irradiation, which indicates that the NB process is an ultralow-damage process. Therefore, the NB process may have tremendous potential to play an important role in the micro- and nano-fabrication processes.
Electrical Detection of Propagating Spin Waves Controlled by a Local Magnetic Field Induced by a DC Current
Authors: Bai Lihui , Kohda Makoto , Nitta Junsaku
Published: April 2010

Propagation of spin waves was studied in electrical ways. Spin waves were excited locally in a permalloy strip by a microwave through a coplanar waveguide and were detected by an electrical technique based on spin rectification effect. By a local magnetic field induced by a DC current, the propagation of spin waves was suppressed in the permalloy strip. We demonstrated that spin wave excitation, manipulation and detection in permalloy strip are possible by electrical ways. And microwave leakage from the coplanar waveguide and local excitation of spin waves are discussed in this paper.
Spin–Orbit Interaction in an In0.53Ga0.47As/In0.7Ga0.3As Shallow Two-Dimensional Electron Gas Located 5 nm below InP Surface Barrier
Authors: Kohda Makoto , Shibata Toshiya , Nitta Junsaku
Published: April 2010

A two-dimensional electron gas (2DEG) formed near a semiconductor surface has an advantage for the injection and detection of electron spins to realize a spin field-effect transistor (spin FET). Here, we investigated the strength of spin–orbit interaction (SOI) in 26.5 nm In0.52Al0.48As and AlAs surface layer/5 nm InP/7.5 nm In0.53Ga0.47As/10 nm In0.7Ga0.3As 2DEGs. By the selective wet etching of In0.52Al0.48As and InP layers, we achieved a 5 nm InP/In0.53Ga0.47As/In0.7Ga0.3As 2DEG with a carrier density of 1.06×1012 cm-2. Magnetoconductance is measured to evaluate the strength of Rashba SOI by the quantum correction of the conductance in the ballistic regime developed by Golub. The Rashba SOI parameter α reaches 3.85×10-12 eV m, which yields a spin rotation angle of 2.34π within the elastic scattering length indicating a good candidate for the channel of a spin FET.
Advanced Macro-Model with Pulse-Width Dependent Switching Characteristic for Spin Transfer Torque Based Magnetic-Tunnel-Junction Elements
Authors: Kim Sojeong , Lee Seungjun , Shin Hyungsoon
Published: April 2010

In spin transfer torque (STT)-based magnetic tunnel junction (MTJ), the switching depends on the current pulse-width as well as the magnitude of the switching current. We present an advanced macro-model of an STT-MTJ for a circuit simulator such as HSPICE. The macro-model can simulate the dependence of switching behavior on current pulse-width in an STT-MTJ. An imaginary resistor–capacitor (RC) circuit is adopted to emulate complex timing behavior which cannot be described nicely by existing functions in HSPICE. Simulation results show the resistance–current (R–I) curve and timing behavior is in good agreement with the experimental data.
Silicon Nanowire Array Solar Cell Prepared by Metal-Induced Electroless Etching with a Novel Processing Technology
Authors: Um Han-Don , Jung Jin-Young , Seo Hong-Seok , Park Kwang-Tae , Jee Sang-Won , Moiz S. A. , Lee Jung-Ho
Published: April 2010

We inexpensively fabricated vertically aligned Si nanowire solar cells using metal-induced electroless etching and a novel doping technique. Co-doping of boron and phosphorus was achieved using a spin-on-doping method for the simultaneous formation of a front-side emitter and a back surface field in a one-step thermal cycle. Nickel electroless deposition was also performed in order to form a continuous metal grid electrode on top of an array of vertically aligned Si nanowires. A highly dense array of Si nanowires with low reflectivity was obtained using Ag nanoparticles of optimal size (60–90 nm). We also obtained an open circuit voltage of 544 mV, a short circuit current of 14.68 mA/cm2, and a cell conversion efficiency of 5.25% at 1.5AM illumination. The improved photovoltaic performance was believed to be the result of the excellent optical absorption of the Si nanowires and the improved electrical properties of the electroless deposited electrode.
Device and Circuit Codesign Strategy for Application to Low-Noise Amplifier Based on Silicon Nanowire Metal–Oxide–Semiconductor Field Effect Transistors
Authors: Cho Seongjae , Jhon Hee-Sauk , Lee Jung Hoon , Park Se Hwan , Shin Hyungcheol , Park Byung-Gook
Published: April 2010

In this study, a full-range approach from device level to circuit level design is performed for RF application of silicon nanowire (SNW) metal–oxide–semiconductor field effect transistors (MOSFETs). Both DC and AC analyses have been conducted to confirm the advantages of an SNW MOSFET over the conventional planar (CPL) MOSFET device having dimensional equivalence. Besides the intrinsic characteristic parameters, the extrinsic resistance and capacitance caused by wiring components are extracted from each device. On the basis of these intrinsic and extrinsic parameters, a multi-fingered 5.8 GHz low-noise amplifier (LNA) design adopting SNW MOSFETs has been achieved, which shows an improved gain of 17.5 dB and a noise figure of 3.1 dB over a CPL MOSFET LNA.
Hole Transport Mechanism in Silicon and Germanium Nanowire Field Effect Transistors
Authors: Minari Hideki , Mori Nobuya
Published: April 2010

Atomistic hole transport simulation based on nonequilibrium Green's function method and tight-binding approximation has been performed for silicon (Si) and germanium (Ge) p-type nanowire (NW) field-effect transistors (FETs) with the diameter ranging from 1.6 to 3 nm. Simulation results show that the drain current density increases with increasing NW diameter and the difference in the drain current between Si and Ge NW FETs becomes smaller with decreasing NW diameter.
Analytical Compact Model of Ballistic Cylindrical Nanowire Metal–Oxide–Semiconductor Field-Effect Transistor
Authors: Numata Tatsuhiro , Uno Shigeyasu , Nakazato Kazuo , Kamakura Yoshinari , Mori Nobuya
Published: April 2010

We propose a compact model of drain current in the ballistic mode in a cylindrical gate-all-around metal–oxide–semiconductor field-effect transistor (MOSFET). Wave functions of electrons in a channel are represented by a linear combination of wave functions in a cylindrical infinite quantum well. With these wave functions, the energy levels of electrons in a channel are analytically derived by approximately solving the Schrödinger equation. Drain current is obtained using a coupled equation of electron energy levels and a current equation for ballistic transport. Electron energy levels are compared with numerical simulation results. The electron energy levels obtained using our compact model demonstrate excellent agreement with numerical simulation results. With our compact model, surface potential, potential shape in the confinement plane, total charge density, electron energy level, and drain current are calculated self-consistently with only two fitting parameters and one transcendental equation.
Comparison of Series Resistance and Mobility Degradation Extracted from n- and p-Type Si-Nanowire Field Effect Transistors Using the Y-Function Technique
Authors: Baek Rock-Hyun , Baek Chang-Ki , Jung Sung-Woo , Yeoh Yun Young , Kim Dong-Won , Lee Jeong-Soo , Kim Dae M. , Jeong Yoon-Ha
Published: April 2010

The series resistance R
sd and the electron and hole mobilities, extracted from n- and p-type Si-nanowire field effect transitors (Si-NWFETs) using the Y-function technique are compared. Both n- and p-NWFETs show similar R
sd values but n-NWFETs have larger R
sd variation from device to device than p-NWFETs. Also, compared with n-NWFETs, p-NWFETs exhibit higher low-field mobility µ0 but severe mobility degradation, regardless of channel length in the high gate voltage V
gs region. With decreasing channel length and increasing lateral electric field for a given drain voltage, n-NWFETs exhibit low-field mobility (µ0) degradation resulting from the velocity saturation. In contrast, the hole mobility in p-NWFETs remains nearly constant and is consistant with its larger critical electric field, E
c.
Shape Effects on the Performance of Si and Ge Nanowire Field-Effect Transistors Based on Size Dependent Bandstructure
Authors: Koong Chee Shin , Samudra Ganesh , Liang Gengchiau
Published: April 2010

In this paper, we evaulated the shape and size effects of Si and Ge nanowire (NW) field-effect transistors (FETs) on device performance using sp3d5s*tight-binding (TB) model and semi-classical top-of-barrier ballistic transport model. Our simulation results show that smaller cross-sectional area is desirable for high frequency device applications and for larger ON-state currents, square cross-section may be desirable due to larger cross-sectional area and insulator capacitance. Furthermore, it is also observed that due to quantum effects, the gate capacitance to gate oxide capacitance (Cg/Cox) ratio for the small size NW FETs could be much less than one, rendering the classical assumptions and calculations invalid for nano scale FETs. In this sub-nano region, therefore, a new set of assumptions and calculations in terms of effective mass, bandgap, and one-dimensional density-of-states should be implemented as quantum effects start to play an important role in device performance.
Molecular Dynamics Simulation of Heat Transport in Silicon Nano-structures Covered with Oxide Films
Authors: Zushi Tomofumi , Kamakura Yoshinari , Taniguchi Kenji , Ohdomari Iwao , Watanabe Takanobu
Published: April 2010

We perform a series of molecular dynamics (MD) simulations to investigate the heat transport in Si nano-structures, while explicitly including oxide cover layers in the simulation system for the first time. The dependences of thermal diffusion velocity on the thicknesses of the SiO2 film and Si lattice are investigated. The results show that thermal diffusion velocity decreases with Si lattice thickness and does not depend on SiO2 film thickness.
Electron–Modulated-Acoustic-Phonon Interactions in a Coated Silicon Nanowire
Authors: Hattori Junichi , Uno Shigeyasu , Mori Nobuya , Nakazato Kazuo
Published: April 2010

Modulated acoustic phonons and their interactions with electrons in a coated cylindrical silicon nanowire (SiNW) are investigated theoretically. The impact of acoustic phonons on the interactions is encapsulated in the form factor. The form factor for a SiO2-coated SiNW is larger than that calculated using bulk phonons while that for a HfO2-coated SiNW is smaller, when the coating shell thickness is sufficiently large. This result can be qualitatively explained by the relationship of acoustic impedance between the nanowire core and shell. The form factor reduction directly weakens the interactions, and thereby provides higher electron mobility than that limited by bulk phonons.
Growth of Carbon Nanotubes on HfO2 towards Highly Sensitive Nano-Sensors
Authors: Uchino Takashi , Ayre Greg N. , Smith David C. , Hutchison John L. , Groot C. H. de , Ashburn Peter
Published: April 2010

Carbon nanotube (CNT) growth on HfO2 is reported for the first time. The process uses a combination of Ge and Fe nanoparticles and achieves an increase in CNT density from 0.15 to 6.2 µm length/µm2 compared with Fe nanoparticles alone. The synthesized CNTs are assessed by the fabrication of back-gate CNT field-effect transistors with Al source/drain contacts for nano-sensor applications. The devices exhibit excellent p-type behavior with an I
on/I
off ratio of 105 and a steep sub-threshold slope of 130 mV/dec.
First-Principles Calculations on Σ3 Grain Boundary Transition Metal Impurities in Multicrystalline Silicon
Authors: Suvitha Ambigapathy , Venkataramanan Natarajan Sathiyamoorthy , Sahara Ryoji , Mizuseki Hiroshi , Kawazoe Yoshiyuki
Published: April 2010

We have carried out a density functional theory study on the Σ3 (111) silicon grain boundary, and calculated the impurity effect of Ni, Fe, Cu, and Cr atoms doped near the grain boundary at both interstitial and substitutional sites. The segregation energy for the impurities follows the order of Fe greater than Cu, Ni, and Cr at the substitutional site and Cr greater than Cu, Fe, and Ni, at the interstitial site. The calculated values were positive, indicating that segregation is not favored in the Σ3 (111) grain boundaries. When the metal impurity is placed at the substitutional site, a new state in the fundamental gap was observed in the density of states, the band gap is reduced, which may have an effect on the solar cell performance. The calculated magnetic moments for the transition-metal-doped grain boundary show that they were quenched for Ni, Fe, and Cu point defects.
Selection of Material for the Back Electrodes of Thin-Film Solar Cells Using Polycrystalline Silicon Films Formed by Flash Lamp Annealing
Authors: Ohdaira Keisuke , Fujiwara Tomoko , Endo Yohei , Shiba Kazuhiro , Takemoto Hiroyuki , Matsumura Hideki
Published: April 2010

Flash lamp annealing (FLA), a rapid annealing technique with a millisecond-order duration, can form polycrystalline silicon (poly-Si) films of a few µm thickness on glass substrates by crystallizing precursor amorphous Si (a-Si) films without serious thermal damage to the substrates. We attempt to use several kinds of metal films for adhesion layers inserted between the Si films and the glass substrates to prevent Si film peeling during FLA. One of the requirements for the insertion metals is a melting point (T
melt) higher than 1414 °C, to which the metal films could be heated during the crystallization induced by FLA. Of the metal films attempted, only Cr films can prevent Si film peeling from soda lime glass substrates, which have a much larger thermal expansion coefficient than quartz, indicating the necessity of sufficient adhesiveness to glass and Si as well as of a high T
melt. Actual solar cell operation is demonstrated using a flash-lamp-crystallized poly-Si film as an absorber layer and a Cr film as a back electrode.
Epitaxial Growth and Photoresponse Properties of BaSi2 Layers toward Si-Based High-Efficiency Solar Cells
Authors: Matsumoto Yuta , Tsukada Dai , Sasaki Ryo , Takeishi Michitoshi , Saito Takanobu , Suemasu Takashi , Usami Noritaka , Sasase Masato
Published: April 2010

We have grown BaSi2 epitaxial films and polycrystalline films by molecular-beam epitaxy on Si(111) and on (111)-oriented 100-nm-thick polycrystalline Si layers fabricated by an aluminum-induced crystallization method on SiO2, respectively. Electron backscatter diffraction analysis was performed on the 200-nm-thick BaSi2 epitaxial film and the grain size of the film was found to be approximately 3–10 µm. Photocurrents were clearly observed for the BaSi2 (900 nm)/Si and BaSi2 (300 nm)/SiO2 samples for photons with energies greater than 1.25 eV at room temperature when bias voltage was applied between the 1.5-mm-spacing striped electrodes formed on the surface. The photoresponsivity of the samples increased sharply with increasing photon energy and attained its maximum at approximately 1.60 eV. From the temperature dependence of the photoresponsivity, the activation energies of the BaSi2 epitaxial films and polycrystalline films were estimated to be approximately 6 and 52 meV, respectively.
Improvements in Optoelectrical Properties of GaAsN by Controlling Step Density during Chemical Beam Epitaxy Growth
Authors: Suzuki Hidetoshi , Inagaki Makoto , Honda Takahiko , Ohshita Yoshio , Kojima Nobuaki , Yamaguchi Masafumi
Published: April 2010

Improvements in optoelectrical properties of GaAsN are demonstrated by chemical beam epitaxy (CBE) growth on high-step-density GaAs substrates. The step density at the growing surface is controlled using 2, 4, and 10° off GaAs(001) wafers as substrates. The number of carrier scattering centers induced by N (SC
N) in the grown GaAsN films is quantitatively evaluated from the temperature dependence of hole mobility and used as an indicator of film quality. In previous studies, SC
N increased with increasing N composition independently of the growth technique used. By CBE with high-step-density substrates, the reduction in SC
N is achieved. This method also improves the emission intensity of cathode luminescence.
High-Performance Transparent Conducting Ga-Doped ZnO Films Deposited by RF Magnetron Sputter Deposition
Authors: Kim Jun Kwan , Lee Jae Min , Lim Jung Wook , Kim Je Ha , Yun Sun Jin
Published: April 2010

Ga-doped zinc oxide (GZO) films were deposited using rf magnetron sputter deposition and a Ga2O3(5 wt %)-doped ZnO ceramic target under various deposition conditions. The effects of each deposition condition on the electrical, structural, and optical properties of the GZO films were investigated to obtain a transparent conducting oxide (TCO) with a high transmittance and a low resistivity for a-Si:H thin-film solar cells. Resistivity showed a strong dependence on working pressure and rf power. The lowest resistivity of 1.9×10-4 Ω·cm was obtained at an rf power density of 2.47 W/cm2. The highest figure of merit for the use of TCO was achieved in the 800-nm-thick GZO film [ρ=2.1×10-4 Ω·cm, average transmittance (400–800 nm) = 92.1%] deposited at 10 mTorr and an rf power density of 1.85 W/cm2. These results indicate that the high-performance TCO fabricated in this work is suitable for use as a transparent electrode layer for thin-film solar cells.
Modeling of Dye-Sensitized Solar Cells Based on TiO2 Electrode Structure Model
Authors: Onodera Mari , Ogiya Kei , Suzuki Ai , Tsuboi Hideyuki , Hatakeyama Nozomu , Endou Akira , Takaba Hiromitsu , Kubo Momoji , Miyamoto Akira
Published: April 2010

Our newly developed our original multi-scale simulator was applied to dye-sensitized solar cells (DSSC) to investigate the effect of the complex porous structure of a TiO2 electrode on cell performance. We simulated the current–voltage (I–V) characteristics for various models of porous structures of DSSCs including cis-di(thiocyanato)-bis(2,2'-bipyridyl-4,4'-dicarboxylic acid)-ruthenium(II) (N3 dye). The short-circuit current density increased with decreasing porosity, overlap ratio, and particle diameter. A DSSC system including TA–St–CA (C30H22N2O2) as a sensitizer was also investigated for comparison with the system with N3 dye. The dependence of the amount of dye adsorption on the I–V characteristics was evaluated. A linear relation between the short-circuit current density and the amount of dye adsorption was found. The obtained results indicate that our developed multi-scale simulator is a powerful tool for obtaining insights into the effect of properties in DSSCs and for optimizing the DSSC structure.
Acute inflammation reduces kisspeptin immunoreactivity at the arcuate nucleus and decreases responsiveness to kisspeptin independently of its anorectic effects
Authors: Castellano J. M. , Bentsen A. H. , Romero M. , Pineda R. , Ruiz-Pino F. , Garcia-Galiano D. , Sánchez-Garrido M. A. , Pinilla L. , Mikkelsen J. D. , Tena-Sempere M.
Published: April 2010

Severe inflammatory challenges are frequently coupled to decreased food intake and disruption of reproductive function, the latter via deregulation of different signaling pathways that impinge onto GnRH neurons. Recently, the hypothalamic Kiss1 system, a major gatekeeper of GnRH function, was suggested as potential target for transmitting immune-mediated repression of the gonadotropic axis during acute inflammation, and yet key facets of such a phenomenon remain ill defined. Using lipopolysaccharide S (LPS)-treated male rats as model of inflammation, we document herein the pattern of hypothalamic kisspeptin immunoreactivity (IR) and hormonal responses to kisspeptin during the acute inflammatory phase. LPS injections induced a dramatic but transient drop of serum LH and testosterone levels. Suppression of gonadotropic function was associated with a significant decrease in kisspeptin-IR in the arcuate nucleus (ARC) that was not observed under conditions of metabolic stress induced by 48-h fasting. In addition, absolute responses to kisspeptin-10 (Kp-10), in terms of LH and testosterone secretion, were significantly attenuated in LPS-treated males that also displayed a decrease in food intake and body weight. Yet pair-fed males did not show similar alterations in LH and testosterone secretory responses to Kp-10, whose magnitude was preserved, if not augmented, during food restriction. In summary, our data document the impact of acute inflammation on kisspeptin content at the ARC as key center for the neuroendocrine control of reproduction. Our results also suggest that suppressed gonadotropic function following inflammatory challenges might involve a reduction in absolute responsiveness to kisspeptin that is independent of the anorectic effects of inflammation.
Detection of Outliers and Patches in Bilinear Time Series Models
Authors: Chen Ping , Li Ling , Liu Ye , Lin Jin-Guan
Published: April 2010

We propose a Gibbs sampling algorithm to detect additive outliers and patches of outliers in bilinear time series models based on Bayesian view. We first derive the conditional posterior distributions, and then use the results of first Gibbs run to start the second adaptive Gibbs sampling. It is shown that our procedure could reduce possible effects on masking and swamping. At last, some simulations are performed to demonstrate the efficacy of detection and estimation by Monte Carlo methods.
Systemic Inflammation in Chronic Obstructive Pulmonary Disease: May Adipose Tissue Play a Role? Review of the Literature and Future Perspectives
Authors: Tkacova Ruzena
Published: April 2010

Chronic obstructive pulmonary disease (COPD) is a major cause of morbidity and mortality worldwide. Low-grade systemic inflammation is considered a hallmark of COPD that potentially links COPD to increased rate of systemic manifestations of the disease. Obesity with/without the metabolic syndrome and cachexia represent two poles of metabolic abnormalities that may relate to systemic inflammation. On one hand systemic inflammatory syndrome likely reflects inflammation in the lungs, i.e. results from lung-to plasma spillover of inflammatory mediators. On the other hand, obesity-related hypoxia results in local inflammatory response within adipose tissueper se, and may contribute to elevations in circulatory mediators by spillover from the adipose tissue to the systemic compartment. The extent to which systemic hypoxia contributes to the adipose tissue inflammation remains unknown. We assume that in patients with COPD and concurrent obesity at least three factors play a role in the systemic inflammatory syndrome: the severity of pulmonary impairment, the degree of obesity-related adipose tissue hypoxia, and the severity of systemic hypoxia due to reduced pulmonary functions. The present review summarizes the epidemiological and clinical evidence linking COPD to obesity, the role of adipose tissue as an endocrine organ, and the role of hypoxia in adipose tissue inflammation.
Modeling and Control of 2D Grasping under Rolling Contact Constraints between Arbitrary Shapes: A Riemannian-Geometry Approach
Authors: Arimoto Suguru , Yoshida Morio
Published: April 2010

Modeling, control, and stabilization of dynamics of two-dimensional object grasping by using a pair of multijoint robot fingers are investigated under rolling contact constraints and arbitrariness of the geometry of the object and fingertips. First, modeling of rolling motion between 2D rigid bodies with arbitrary shape is treated under the assumption that the two contour curves coincide at the contact point and share the same tangent. The rolling constraints induce the Euler equation of motion that is parameterized by a pair of arclength parameters and constrained onto the kernel space as an orthogonal complement to the image space spanned from all the constraint gradients. Furthermore, it is shown that all the Pfaffian forms of the rolling constraints are integrable in the sense of Frobenius and therefore the rolling contacts are regarded as a holonomic constraint. The Euler-Lagrange equation of motion of the overall fingers/object system is rederived together with a couple of first-order differential equations that express evolution of contact points in terms of quantities of the second fundamental form. A control signal called “blind grasping” is defined and shown to be effective in maintenance or stabilization of grasping without using the details of object shape and parameters or external sensing. An extension of the Dirichlet-Lagrange stability theorem to a system of DOF-redundancy under constraints is discussed by introducing a Morse-Bott function and deriving its Hessian, in a special case that the object to be grasped is a parallelepiped.
Fibroblast Growth Factor Receptor 3 Mutation Analysis on Voided Urine for Surveillance of Patients with Low-Grade Non-Muscle–Invasive Bladder Cancer
Authors: Zuiverloon Tahlita C.M. , van der Aa Madelon N.M. , van der Kwast Theo H. , Steyerberg Ewout W. , Lingsma Hester F. , Bangma Chris H. , Zwarthoff Ellen C.
Published: April 2010

Purpose: Mutations in the fibroblast growth factor receptor 3 (FGFR3) have been found in 70% of the low-grade non-muscle–invasive bladder cancer (NMI-BC) tumors. We aim to determine the potential of FGFR3 mutation analysis on voided urine to detect recurrences during surveillance of patients with low-grade NMI-BC.

Experimental Design: FGFR3 mutation status of the study inclusion tumor was determined from 200 low-grade NMI-BC patients. Patients with an FGFR3-mutant inclusion tumor were selected for analysis and monitored by cystoscopy, and voided urine samples were collected. FGFR3 mutation analysis was done on 463 prospectively collected urines. Sensitivity and predictive value of the assay were determined for detection of concomitant recurrences. Longitudinal and Cox time-to-event analyses were done to determine the predictive value for detection of future recurrences.

Results: Median follow-up was 3.5 years. The sensitivity of the assay for detection of concomitant recurrences was 26 of 45 (58%). Of the 105 positive urine samples, 85 (81%) were associated with a concomitant or a future recurrence. An FGFR3-positive urine was associated with a 3.8-fold (P < 0.0001) higher risk of having a recurrence in the Cox analysis. In contrast, only 41 of 358 (11%) FGFR3-negative urine samples were associated with a recurrence. Positive predictive value increased from 25% to 90% in patients having consecutive FGFR3-positive urine tests.

Conclusions: FGFR3 mutation analysis on voided urine is a simple and noninvasive diagnostic method for detection of recurrences during surveillance of patients presenting with a low-grade FGFR3-mutant NMI-BC tumor. Clin Cancer Res; 16(11); 3011–8. ©2010 AACR.
Telomere Maintenance and DNA Damage Responses during Lung Carcinogenesis
Authors: Lantuejoul Sylvie , Raynaud Christophe , Salameire Dimitri , Gazzeri Sylvie , Moro-Sibilot Denis , Soria Jean-Charles , Brambilla Christian , Brambilla Elizabeth
Published: April 2010

Purpose: Telomere shortening is an early event in bronchial carcinogenesis, preceding P53/Rb pathway inactivation and telomerase reactivation, and leading to DNA damage responses (DDR). As their inactivation in cancer increases genetic instability, our objective was to identify the chronology of telomere machinery critical events for malignant progression.

Experimental Design: We have evaluated telomere length by fluorescence in situ hybridization and analyzed DDR proteins p-CHK2, p-ATM, and p-H2AX, and telomeric maintenance proteins TRF1 and TRF2 expression by immunohistochemistry in normal bronchial/bronchiolar epithelium, and in 109 bronchial preneoplastic lesions, in comparison with 32 squamous invasive carcinoma (SCC), and in 27 atypical alveolar hyperplasia (AAH) in comparison with 6 adenocarcinoma in situ (AIS; formerly bronchiolo-alveolar carcinoma) and 24 invasive adenocarcinoma (ADC).

Results: Telomere length critically shortened at bronchial metaplasia stage to increase gradually from dysplasia to invasive SCC; in bronchiolo-alveolar lesions, telomere length decreased from normal to AIS and increased from stage I to II to stage III to IV ADC. Expression of TRF1 and TRF2 increased progressively from dysplasia to SCC and from AAH to invasive ADC. The expression of concomitant DDR proteins increased significantly from low- to high-grade dysplasia and from AAH to AIS and stage I to II ADC. P-CHK2 and p-H2AX expressions were highly correlated and both decreased, along with p-ATM, in SCC and advanced ADC.

Conclusion: Telomere attrition occurs at the earliest stage of lung carcinogenesis as an initiating event, preceding TRF1 and TRF2 overexpression for telomere stabilization. In contrast, dismiss of DDR, through p-H2AX and p-CHK2 downregulation, represents a late progressing event associated with SCC and ADC progression. Clin Cancer Res; 16(11); 2979–88. ©2010 AACR.
Genetic Variation in 3-Hydroxy-3-Methylglutaryl CoA Reductase Modifies the Chemopreventive Activity of Statins for Colorectal Cancer
Authors: Lipkin Steven M. , Chao Elizabeth C. , Moreno Victor , Rozek Laura S. , Rennert Hedy , Pinchev Mila , Dizon Diana , Rennert Gad , Kopelovich Levy , Gruber Stephen B.
Published: April 2010

Genetic variation in 3-hydroxy-3-methylglutaryl CoA reductase (HMGCR), the rate-limiting enzyme in cholesterol synthesis, modifies the effect of statins on serum cholesterol levels. Long-term use of statins is associated with a reduced risk of colorectal cancer (CRC) in some, but not all, studies. We genotyped variants in 40 candidate genes important for cholesterol synthesis and metabolism in a population-based case-control study of CRC involving 2,138 incident cases and 2,049 population-based controls. We identified a single-nucleotide polymorphism in the HMGCR gene that significantly modified the protective association between statins and CRC risk. Compared with nonusers, the unadjusted odds ratio of CRC among statin users with the A/A genotype of rs12654264 in HMGCR was 0.3 (95% confidence interval, 0.18-0.51) and among statin users with the T/T genotype was 0.66 (95% confidence interval, 0.41-1.06; P-interaction = 0.0012). This genetic variant (A/A genotype of rs12654264) also was associated with lower serum levels of low-density lipoprotein among all cases and controls. In colon cancer cell lines, the reduction in cholesterol levels after statin treatment was substantially stronger in cells carrying the A/A genotype, and this difference was related to alternative splicing involving the HMGCR statin-binding domain. We anticipate that these data may advance the development of personalized statin use for reducing the risk of cancer as well as cardiovascular disease among the approximately 25 million people currently using statins worldwide. Cancer Prev Res; 3(5); 597–603. ©2010 AACR.
Communicating Genetic and Genomic Information: Health Literacy and Numeracy Considerations
Authors: Lea D.H. , Kaphingst K.A. , Bowen D. , Lipkus I. , Hadley D.W.
Published: April 2010

Genomic research is transforming our understanding of the role of genes in health and disease. These advances, and their application to common diseases that affect large segments of the general population, suggest that researchers and practitioners in public health genomics will increasingly be called upon to translate genomic information to individuals with varying levels of health literacy and numeracy. This paper discusses the current state of research regarding public understanding of genetics and genomics, the influence of health literacy and numeracy on genetic communication, and behavioral responses to genetic and genomic information. The existing research suggests that members of the general public have some familiarity with genetic and genomic terms but have gaps in understanding of underlying concepts. Findings from the limited research base to date indicate that health literacy affects understanding of print and oral communications about genetic and genomic information. Numeracy is also likely to be an important predictor of being able to understand and apply this information, although little research has been conducted in this area to date. In addition, although some research has examined behavior change in response to the receipt of information about genetic risk for familial disorders and genomic susceptibility to common, complex diseases, the effects of health literacy and numeracy on these responses have not been examined. Potential areas in which additional research is needed are identified and practical suggestions for presenting numeric risk information are outlined. Public health genomics researchers and practitioners are uniquely positioned to engage in research that explores how different audiences react to and use genomic risk information.
Oxacillin Resistance of Staphylococcus aureus Isolated from the University Hospital of Botucatu Medical School in Brazil
Authors: Martins André , Pereira Valéria Cataneli , Cunha Maria de Lourdes R.S.
Published: April 2010

Background: Oxacillin is the main drug used for the treatment of Staphylococcus aureus infections. However, resistance of S. aureus to oxacillin has become a major problem over recent decades. The aim of this study was to determine oxacillin resistance in S. aureus isolates obtained from the University Hospital of the Botucatu Medical School, Universidade Estadual Paulista, Brazil. Materials and Methods: A total of 102 isolates collected between 2002 and 2006 were analyzed by detection of the mecA gene, cefoxitin and oxacillin disk diffusion methods, screening test on Mueller-Hinton agar and E-test. Results: Forty-six (45.1%) isolates were mecA positive. The oxacillin disk diffusion method showed 86.9% sensitivity and 91.1% specificity. The screening method and cefoxitin disk diffusion presented a similar sensitivity (91.3%) and the same specificity. The E-test showed 97.8% sensitivity and the same specificity as observed for the other methods. Conclusions: The E-test yielded the best results compared to the other methods.