bluuebunny/crossref_metadata_2025 huggingface dataset:
Large Magnetoresistance Switching Phenomena in Nanoconduction Path Formed with Dielectric Breakdown of SiO2 Multilayered with Ferromagnetic Film
Authors: Shiotani Yuichi , Shimomura Kohei , Shimizu Tomohiro , Shingubara Shoso
Published: June 2011

A large magnetoresistance exceeding 290% at room temperature was observed in a nanoconduction path (NCP) formed by dielectric breakdown of an SiO2 layer in contact with a ferromagnetic layer. Switching of the resistance between a low-resistance state (LRS) and a high-resistance state (HRS) occurred at magnetic fields of 0.2–0.6 T. The current–voltage characteristic of HRS showed a clear tunneling behavior, while that of LRS showed a weak nonlinearity. A set-up process with some amount of current stress was necessary to observe magnetoresistance switching. It is suggested that a nanogap is formed in a ferromagnetic NCP as a result of electromigration during the set-up process. The detailed mechanism has not yet been understood, however, magnetoresistance switching seems to be caused by a reproducible change of the nanogap distance concomitant with a switching of the magnetization of a ferromagnetic NCP.
Ferromagnetic MnAs Nanocluster Composites Position-Controlled on GaAs (111)B Substrates toward Lateral Magnetoresistive Devices
Authors: Komagata Keita , Hara Shinjiro , Ito Shingo , Fukui Takashi
Published: June 2011

The authors report on the ordered planar arrangements of ferromagnetic MnAs/AlGaAs nanocluster (NC) composites grown on partially SiO2-masked GaAs (111)B substrates by selective-area metal–organic vapor phase epitaxy for lateral magnetoresistive device applications. Each of the NCs in the composites has an elongated shape and a different size to control their magnetized directions and coercive forces. By designing and optimizing the initial SiO2-mask openings formed by electron beam lithography on the template wafers, we fabricate elongated NC composites with a spatial gap of 5 to 10 nm between two NCs and an elongated NC connected to a relatively large MnAs NC electrode. Cross-sectional lattice images taken with a transmission electron microscope show that the interfaces between MnAs and AlGaAs layers of the NCs are atomically abrupt. Magnetic force microscopy at room temperature reveals that the magnetized directions in each of the NC composites are rotated by around 180° when the applied direction of the external magnetic fields is rotated in the opposite direction.
Silicon Beam Microelectromechanical Systems Resonator with a Sliding Electrode
Authors: Oka Tomohiro , Ishino Takuya , Tanigawa Hiroshi , Suzuki Kenichiro
Published: June 2011

A silicon beam microelectromechanical systems (MEMS) resonator with a sliding driving electrode (DE) has been investigated. Although the narrow gap between a driving electrode and a resonant beam greatly improves the resonator performance, it has been difficult to fabricate the narrow gap owing to the process limitation. In this study, the gap is decreased by sliding the driving electrode after the resonator process is completed (postprocessed narrow gap formation). The effective gap length for a fabricated resonator was decreased to 0.84 µm after the pull-in, while the initial gap was 3.44 µm. After the pull-in, the fabricated resonator vibrated at the 899.5 kHz resonant frequency (the Q-factor of 6600). The resonant beam displacement amplitude increased 17.5 times compared with that for the as-fabricated (before the pull-in) resonator. In the electrical domain, the magnitude of the impedance largely decreased from ∼58 to 3.85 MΩ. The large phase transition, 50°, was also measured. From these results, largely improved resonator characteristics due to the narrow gap effect were confirmed. Moreover, the displacement amplitude ratio of the sliding DE to the resonant beam was found to be less than 4.5×10-5for the resonator after the pull-in. This implies that the vibration of the sliding DE could affect negligibly the overall beam resonator vibration.
Self-Aligned Formation of Nanoscale Phase Change Materials for Nonvolatile Memory Application
Authors: Lee Seung-Yun , Jung Soun , Yoon Sung-Min , Park Young Sam
Published: June 2011

We present a novel concept for the formation of active phase change regions in nonvolatile memory. Nanoscale phase change materials were prepared in a self-aligned manner by intermixing of two different components chosen from Ge, SiGe, Sb, and SbTe. The interdiffusion of Ge and Sb atoms increased gradually with increasing annealing temperature to 500 °C, whereas Ge, Sb, and Te atoms were completely mixed at 300 °C or higher. In addition, we found that Ge and Sb elements disappeared at 600 °C, exceeding the eutectic point (592 °C) of GeSb. Transmission electron microscopy revealed that a GeSb layer about 20 nm thick formed at the interface between the Ge and Sb layers. The memory devices fabricated based on the concept exhibited reduced programming currents, which is attributed to the small-sized phase change material made using the self-aligned formation.
Controllable Growth of Vertically Aligned Aluminum-Doped Zinc Oxide Nanorod Arrays by Sonicated Sol–Gel Immersion Method depending on Precursor Solution Volumes
Authors: Mamat Mohamad Hafiz , Khusaimi Zuraida , Zahidi Musa Mohamed , Bakar Suriani Abu , Siran Yosri Mohd , Rejab Syahril Anuar Md , Asis Ahmad Jaril , Tahiruddin Shawaluddin , Abdullah Saifollah , Mahmood Mohamad Rusop
Published: June 2011

Aluminium (Al)-doped zinc-oxide (ZnO) nanorod arrays have been successfully prepared using a novel and low-temperature sonicated sol–gel immersion method. The photoluminescence (PL) spectrum reveals the appearance of two emission peaks from the nanorod that are centred at 381 and 590 nm. The nanorod has a hexagonal structure with a flat-end facet, as observed using field-emission electron microscopy (FESEM). Interestingly, all samples have similar surface morphologies and diameter sizes of 40 to 150 nm after immersion in different precursor-solution volumes. The thickness-measurement results show that the thicknesses of the samples increase after immersion in higher precursor-solution volumes. We show for the first time that the growth of nanorod arrays along thec-axis can be controlled using different precursor volumes, and its growth mechanism is discussed. X-ray diffraction (XRD) spectra indicate that the prepared nanorods are ZnO with a hexagonal wurtzite structure that grows preferentially along thec-axis.
A Three-Dimensional Nanostructure Consisting of Hollow TiO2 Spheres Fabricated by Atomic Layer Deposition
Authors: Lee Wen-Jen , Hon Min-Hsiung , Chung Yi-Wen , Lee Jian-Hong
Published: June 2011

In this paper, a process for constructing three-dimensional (3D) nanostructure consisting of hollow TiO2 spheres on an indium tin oxide (ITO) coated glass substrate with easy and accurate shell-thickness controlled by template-assisted atomic layer deposition is reported. Additionally, the crystalline structure and optical properties of 3D hollow TiO2 sphere nanostructure have also been studied. Moreover, in order to measure the absorbance spectrum for a nanostructure accurately that a modification in measurement of absorbance spectrum is suggested.
Effect of Silicon Doping on the Photoluminescence and Photoreflectance Spectra of Catalyst-Free Molecular Beam Epitaxy–Vapor Liquid Solid Grown GaAs Nanowires on (111)Si Substrate
Authors: Suzuki Akio , Mori Takayuki , Fukuyama Atsuhiko , Ikari Tetsuo , Paek Ji-Hyun , Yamaguchi Masahito
Published: June 2011

The optical properties of catalyst-free GaAs nanowires (NWs) grown on a (111)Si substrate were investigated by low-temperature photoreflectance (PR) and photoluminescence (PL) techniques. Although the bandgap energy (E
g) of non-doped NWs agreed well with that of liquid-encapsulated Czochralski-grown semi-insulating bulk, a distinctive PL peak caused by a carbon acceptor to an unspecified donor recombination was observed. Because this recombination was also observed in the Si-doped NW sample, we concluded that a new type of donor was introduced during the NW growth processes. Owing to Si doping, the arsenic vacancy-Si acceptor complex was introduced in the NWs, which showed a broad but large PL band of approximately 1.4 eV. Another important finding was that E
g of the Si-doped NW sample was estimated to be 20 meV lower than that of the non-doped NW sample. This implies that the Si-related donor impurity band in NWs was caused by Si doping.
Upconversion Emission in Er and Cr Co-Doped KNbO3 Phosphors
Authors: Kim Tae-hong , Kim Dae-jin , Jang Woo-young , Moon Ayoung , Lim Ki-Soo , Lee Myeongkyu
Published: June 2011

Near-infrared to visible upconversion emission was observed with 980 nm excitation and analyzed in Er-doped and Er/Cr-codoped KNbO3 phosphors. In both systems, exciton emission appeared at 555 nm under 405 nm excitation. In the codoped phosphors, upconversion emissions in the green, red, and infrared region were observed from the 4S3/2 and 4F9/2 states of Er3+ ions and the 4T2 state of Cr3+ ions respectively. We explain the emissions by two-step absorption of Er ions and the energy transfer processes between Er ions, from Er to Cr ions, and from Cr to Er ions.
Method for Determining the Angle in Two Dimension Nanoscale: Pitch Grating
Authors: Pan Shan-Peng , Liu Tzong-Shi , Tasi Min-Ching , Liou Huay-Chung
Published: June 2011

A two-dimensional (2D) grating is useful for calibrating the accuracy of an electron microscope and atomic force microscope (AFM). An inter laboratory comparison has been carried out for measuring pitches and angles of 2D gratings with 292 and 1000 nm pitches using both AFM and an optical diffractometer (OD). The grating angle at the 292 nm pitch size was obtained at some of the laboratories by the conventional OD method. However, they could not measure the grating angle when the grating pitch was smaller than (λ/2) ×√2, where λ denotes the laser wavelength. We propose a diffraction angle rotation method of grating angle measurements. Using a precision rotary table along with diffractive light, we accurately measure a 2D grating angle for any pitch size larger than λ/2.
Study on Quartz Multitier Mold Fabrication Using Gray Scale Laser Beam Lithography
Authors: Youn Sung-Won , Park Sang-Cheon , Wang Qing , Suzuki Kenta , Hiroshima Hiroshi
Published: June 2011

Gray scale laser beam lithography (G-LBL) is an inexpensive, fast, and simple process for creating a multitier or near-continuous surface topography of microscale components. In this work, the combined use of the microfabrication processes of G-LBL (with a 375 nm diode laser) and reactive ion etching (RIE) was studied to fabricate multitier quartz molds. In the G-LBL process, both pixel pulse length and grayscale level in bitmap images were controlled under a fixed laser power of 10 mW to develop multitier features in an OFPR-800LB resist in a single writing step. By the subsequent CHF3 RIE process, the multitier features defined in the resist were transferred into the underlying quartz with a depth ratio of 1:2.2. Furthermore, the feasibility of the fabricated quartz molds was verified through the UV imprint experiments.
Fabrication Processes for Capacity-Equalized Mold with Fine Patterns
Authors: Suzuki Kenta , Youn Sung-Won , Wang Qing , Hiroshima Hiroshi , Nishioka Yasushiro
Published: June 2011

The variation of residual layer thickness (RLT) by the difference of pattern density is a difficult problem in UV nanoimprint lithography (NIL). A capacity-equalized mold was proposed to solve the problem, and the effectiveness of the concept was validated using a mold with various pattern sizes of hundreds of micrometers. However, the effectiveness should be evaluated at nanometer scales to prove the concept. Here the first challenge has been to fabricate and evaluate a two-step-depth mold with tens of nanometer patterns for the capacity-equalized mold. A two-step-depth mold with sub-100 nm patterns was fabricated by a combination of electron beam lithography and laser beam lithography. We succeeded in fabricating a two-step-structure with a width of around 40 nm, and the widths of the deeper grooves were found to have slightly increased during the second RIE process. The differences in widths were found to vary approximately from 10 to 30 nm. UV nanoimprint was carried out using the two-step-depth mold in order to examine its depth modulation, and to judge whether it could be applied to a NIL process, including a residual-layer-removal process. Fine patterns of 40 nm width were successfully transferred onto the underlying Si wafer from two-step-height resin patterns that were fabricated by UV nanoimprint.
Fabrication of Zero-Mode Waveguide by Ultraviolet Nanoimprint Lithography Lift-Off Process
Authors: Wada Junichi , Ryu Shou , Asano Yuji , Ueno Taro , Funatsu Takashi , Yukawa Takao , Mizuno Jun , Tanii Takashi
Published: June 2011

Zero-mode waveguides for single-molecule fluorescence imaging were fabricated using a simple desktop UV nanoimprint lithography system. An array of 30- to 150-nm-diameter nanoholes was successfully fabricated in an aluminum layer on a thin quartz plate by the single-step lift-off process using the UV-curable resist NIAC 707. Using the nanoholes, we performed real-time single-molecule fluorescence imaging to visualize the cochaperonin GroES binding with and dissociating from the chaperonin GroEL immobilized within the nanoholes. The demonstration revealed that the fluorescence from the GroES binding with the GroEL was three times stronger than the fluorescence from the GroES undergoing Brownian motion, and the real-time single-molecule fluorescence imaging was feasible using the zero-mode waveguide fabricated by the UV nanoimprint lithography lift-off process.
Effects of Granularity of Complementary Patterns in a Capacity-Equalized Mold Used for UV Nanoimprint Lithography
Authors: Wang Qing , Hiroshima Hiroshi , Youn Sung-Won , Suzuki Kenta
Published: June 2011

It is a key issue to obtain a uniform residual layer for a feature of non-uniform pattern densities when applying nanoimprint. To treat this issue, it is proposed to use a capacity-equalized mold, in which deeper complementary cavities are added to the original trench pattern areas in order to make a uniform pattern capacity per unit area throughout the entire mold of varying pattern densities, but without altering the original pattern layout. In this work, we introduced a new concept of granularity to characterize the denseness of complementary patterns. The effects of the granularity of patterns were investigated in a capacity-equalized mold whose corresponding original patterns have varying pattern densities. It was found that the residual layer thicknesses could hold the same values at the areas with different granularities of a capacity-equalized mold. To understand the granularity effects, anin-situresist filling process was studied using a video system. We found that the filling time of the complementary pattern in the capacity-equalized mold increased with increasing granularity. The bubbles trapped in complementary patterns mainly shrank along the directions of the lines, while their widths vertical to the directions of the lines remained almost unchanged until the end when the bubbles disappeared.
Effects of Resist Thickness and Viscoelasticity on the Cavity Filling Capability in Bilayer Thermal Embossing
Authors: Xu Yang , Tsumori Fujio , Toyooka Takuya , Kotera Hidetoshi , Miura Hideshi
Published: June 2011

Poly(methyl methacrylate) (PMMA) bilayer structures are employed as resists to investigate deformation of polymers by microthermal embossing. Owing to the dispersion of Fe3O4 particles in the upper layer, the distinct interface profiles of each layer resist can be observed by scanning electronic microscope (SEM). Deformation and replication fidelity are attributed to a variety of factors in the imprinting process. In particular, the thickness of each resist layer and the viscoelasticity of different molecular weight polymers play the most crucial roles among these factors. Based on experimental results, we improved the deformation models of imprinting for bilayer PMMA material and evaluated the models via specific parameters: the degree of deformation of the lower layer (D
L), the fraction of cavity filling of the lower layer (F
L), and variation in the fraction of the upper layer thickness (K

i
). The final pattern of the upper or lower layer may be implicated in micro electro mechanical systems (MEMS).
Continuous Concentration and Separation of Microparticles Using Dielectrophoretic Force in a V-Shaped Electrode Array
Authors: Hayashi Masahito , Kaneko Tomoyuki , Yasuda Kenji
Published: June 2011

We have proposed and developed the novel principle of a V-shaped electrode array in a microfluidic pathway for continuous concentration and separation of particles by dielectrophoretic (DEP) force. The advantage of V-shape microelectrode arrays with a microfluidic flow for cell separation is that whole particles are concentrated into the center of a micropathway independent of the difference in their dielectric constants in the X–Y plane, while the particles are split between the top or bottom of the micropathway in the Z-axis direction depending on the differences in their dielectric constants and the applied AC frequency. After the application of a sinusoidal AC voltage of 1 MHz and 20 Vpp, both polystyrene spheres and Bacillus subtilis spores were concentrated at the tip of the V-shaped electrode at the center of microfluidic flow in the X–Y plane independent of their dielectric constant differences. They were also split into two directions in the Z-axis, i.e., polystyrene spheres rose to the top, and spores went down to the bottom depending on their dielectric constant differences and were successfully separated in two layered downstreams. The results indicate the potential of V-shaped electrode arrays for simple continuous purification of mixed particles depending on their dielectric constants.
Improvement of Particle Alignment Control and Precise Image Acquisition for On-Chip High-Speed Imaging Cell Sorter
Authors: Hattori Akihiro , Kaneko Tomoyuki , Yasuda Kenji
Published: June 2011

We have developed a real-time imaging cell sorting system composed of a micrometer-sized gel-electrode-embedded microfluidic sorting chip and a real-time image analysis/recognition unit equipped with a high-speed camera and image processing circuits. For the microfluidic continuous cell sorting, we have examined the precise position and velocity control of flowing particles and the precise acquisition of microscopic images of flowing particles. The results showed that (1) hydrodynamic focusing can line up particles precisely within a range of 5 µm particle size distribution, (2) active air pressure-driven flow velocity control can create the flow in the microfluidic pathways up to 160 mm/s with 0.15 MPa air pressure maintaining linear correlation between air pressure and flow velocity, and (3) 1 µs flash illumination can prevent the blur even under 200 mm/s flow. Applying the above elements into the system, the recognition error of target particles was within 5% for 2 µm particles with 2.5 mm/s flow. The experimental results demonstrate the potential of the image index-based on-chip cell sorter for practical application.
Image-Based Identification of Single Neurons for Noninvasive Imaging Purification
Authors: Terazono Hideyuki , Hayashi Masahito , Kim Hyonchol , Hattori Akihiro , Kaneko Tomoyuki , Yasuda Kenji
Published: June 2011

A single-cell-based screening assay requires strict identification and isolation of particular target cells from a mixture of various kinds of cells. We have developed a visual-image-based on-chip microfluidic cell sorting method for the collection of neurons. One of the advantages of our method of purifying neurons is the direct monitoring and reorganization of neurons with specific image indexes, such as the cell size, shape, internal complexity, and spatial distribution of a fluorescent dye of a specific antibody marker by phase-contrast/fluorescence microscopy and image processing, which has not been realized using conventional diffraction-based cell sorting systems. First, we compared the differences of microscopic images (shapes) of neurons and glia cells, and found that only neurons have neurites extending from the cell body. We also found that the smooth surface shape indicates neurons, and the rough surface shape indicates glia cells. After picking the neuron cells manually chosen by observing their shapes as described above, we confirmed that the purified neurons can be cultivated and can keep their electrophysiological functions on the chip even after the purification procedure. The results indicate the potential of a nonlabel, noninvasive on-chip cell sorting procedure for neurons using micrograph images for an on-chip ultrahigh-speed camera-based imaging cell sorter.
Effect of Flow Rates on Generation of Monodisperse Clay–Poly(N-isopropylacrylamide) Embolic Microspheres Using Hydrodynamic Focusing Microfluidic Device
Authors: Han Kyungsup , Lee Sona , Seo Kyoung Duck , Choi Sung-Up , Lee Jonghwi , Lee Jaehwi , Kwak Byung Kook , Choi Hae-Jin , Kim Dong Sung
Published: June 2011

Vascular embolization is a minimally invasive nonsurgical technique obstructing a blood vessel by lodgment of embolic materials to treat cancers and vascular lesions. In this paper, we have carried out a parametric study of generation of monodisperse clay–poly(N-isopropylacrylamide) (clay–PNIPAAm) embolic microspheres of which size is comparable to a blood vessel (about 400 µm). To achieve monodisperse water-phase clay/NIPAAm microdroplets, we have designed and fabricated a poly(dimethylsiloxane) (PDMS) hydrodynamic focusing microfluidic device (HFMD) for the generation of microdroplets with the affinity of continuous oil-phase fluid to the hydrophobic PDMS taken into account. We have investigated the influence of process-related flow conditions on the microdroplet generation to determine a proper processing window for obtaining monodisperse microdroplets with the fabricated HFMD. A parametric study of generation of monodisperse microdroplets was carried out by changing volumetric flow rates of two immiscible fluids within the determined processing window. For the suggested condition, the fabricated clay–PNIPAAm microspheres of about 400 µm in diameter showed an extremely narrow size distribution with a coefficient of variation of 0.41%. We have also showed the floatability of the fabricated clay–PNIPAAm microspheres in saline and the smooth passage of the microspheres through a commercially available microcatheter asin vitrocharacterization for embolization.
Fabrication of a Flexible Array for Tactile Sensors with Microcantilevers and the Measurement of the Distribution of Normal and Shear Forces
Authors: Hirashima Daiki , Uematsu Tatsuya , Sohgawa Masayuki , Mito Wataru , Kanashima Takeshi , Okuyama Masanori , Noma Haruo
Published: June 2011

A Tactile sensor system consisting of elements with three microcantilevers embedded in a cylindrical elastomer has been fabricated by micro electromechanical systems (MEMS) technology. These sensor small size (3 ×4 mm2) chips are mounted on a flexible sheet, and thus the fabricated sensor array can be set even on a curved surface. In addition, the spacial distribution of normal and shear forces is obtained when two kinds of objects (an acrylic hemisphere and a brass cylinder) come in contact with the fabricated sensor shifted laterally. The distribution results appropriately reflect the surface shape of the object and give the behavior of the forces vector.
Field Emission Ion Source Using a Carbon Nanotube Array for Micro Time-of-Flight Mass Spectrometer
Authors: Han Kyusung , Lee Yuri , Jun Dohan , Lee Soonil , Jung Kwang Woo , Yang Sang Sik
Published: June 2011

In this paper, we present the fabrication and test of a carbon-nanotube (CNT)-based field emission ion source for a micro time-of-flight mass spectrometer (µ-TOF MS). The µ-TOF MS is composed of two parts, i.e., a field emission ion source and a mass analyzer. Molecules are ionized by the impact of electrons emitted from CNTs. We calculated the ion beam path using a commercial electrodynamics simulation tool (Simion ver. 7). The results of the ion beam path simulation show that the ions generated in the effective ionization region can pass only between the first acceleration electrode pair. We fabricated a CNT-based field emission ion source for the µ-TOF MS. The electron current of the field emitter and the ion current of the ion source were measured. Through the characteristic test of a field emission ion source, we confirmed that the fabricated ion source is feasible for the µ-TOF MS.
Flexible Polyimide Micropump Fabricated Using Hot Embossing
Authors: Komatsuzaki Hiroki , Suzuki Kenta , Liu Yingwei , Kosugi Tatsuya , Ikoma Ryuta , Youn Sung-Won , Takahashi Masaharu , Maeda Ryutaro , Nishioka Yasushiro
Published: June 2011

Micropumps are important components of advanced microfluidic systems. Here, polyimide (PI) as an advantageous structural material for flexible micropumps was focused on. This is because PI has many advantageous properties such as high thermal stability and superior mechanical strength. However, the difficulty in realizing an all-PI micropump lies in fabricating microstructures on PI film surfaces. In this paper, we present a novel all-PI micropump fabricated using hot embossing. The micropump had diffuser/nozzle valves and functioned by vibrating a 2-µm-thick PI diaphragm with alternating air pressures between 0 and 10 kPa at a frequency of 3 Hz. The height and diameter of the PI micropump chamber were 200 µm and 5 mm, respectively. The flow rate of water in the micropump was 34 µl/min. This micropump is suitable for flexible microfluidic systems.
Novel Fabrication Method of Microcoil Springs Using Laser-Scan Helical Patterning and Nickel Electroplating
Authors: Horiuchi Toshiyuki , Ishii Hidetoshi , Shinozaki Yasuhide , Ogawa Tetsuya , Kojima Kesao
Published: June 2011

A novel microcoil fabrication method was developed. In the past research, copper microcoils were fabricated by wet-etching copper pipes with helical resist patterns formed using laser-scan lithography. However, etched coil widths often locally fluctuated owing to the influence of the surface and backsurface conditions of the pipes, and it was difficult to consistently fabricate microcoils with homogeneous widths. For this reason, in the new method, microcoils are fabricated by nickel electroplating instead of etching. After forming helical patterns on a fine stainless-steel wire with a diameter of 80 µm, nickel was electroplated in the spaces of resist patterns. Because the adhesion of nickel to the stainless-steel wire was not very strong, helically electroplated nickel was tore off from the core wire, and the microcoil was fabricated when the wire was pulled and lengthened. Next, helical pattern widths and nickel coil widths were evaluated. The homogeneity and reproducibility of both widths were very good, and width variations of nickel microcoils were almost the same level as those of resist space patterns. This finding was considered to indicate that the width fluctuation occurring during the electroplating process was very small. The fabricated nickel coils showed almost linear spring characteristics when they were repeatedly compressed and released. The spring constant of the fabricated coil was approximately 0.16 N/mm. The new method and the fabricated nickel coils will be of practical use.
Convection-Based Tilt Sensor with Minimized Temperature Fluctuation
Authors: Choi Ju Chan , Kong Seong Ho
Published: June 2011

This paper presents a simple and novel method for minimizing the performance dependence of a convection-based tilt sensor on environmental temperature fluctuation. Previously reported convective tilt sensors show considerable fluctuation in output voltage because of various external thermal effects. Therefore, it is necessary to have a complex circuit to compensate the external temperature fluctuation or an additional cautious package to reduce the thermal effect. In this paper, a convective tilt sensor that inhibits the environmental thermal effect without an additional circuit or package is discussed. An integrated thin-film-based thermoelectric device is utilized not only for heating an encapsulated air medium with a symmetric temperature profile when it is balanced, but also for minimizing external thermal effects. The hot junction of the thermoelectric device operates as a heater and the cold one keeps the temperature difference between two junctions constant regardless of the external thermal environment. The proposed tilt sensor showed a fairly linear output voltage within the inclination range of ±90° on two axes and even exhibited a consistent output voltage under various external temperature conditions. The fluctuation rate of the proposed tilt sensor was kept within less than 2% of the output voltage; this was even the case for a temperature range of 25 to 60 °C.
Improved Performances of Acoustic Energy Harvester Fabricated Using Sol/Gel Lead Zirconate Titanate Thin Film
Authors: Kimura Shu , Tomioka Syungo , Iizumi Satoshi , Tsujimoto Kyohei , Sugou Tomohisa , Nishioka Yasushiro
Published: June 2011

Energy harvesters integrable on smart sensor systems have been strongly demanded. Microelectromechanical system (MEMS) acoustic energy harvesters using the first resonance vibration of a lead zirconate titanate (PZT) thin film as a diaphragm have recently been reported. Similar acoustic energy harvesters using the third resonance of a PZT diaphragm fabricated by sol/gel PZT thin film processes exhibited improved generated power density, and it was suggested that the PZT acoustic energy harvester might be suitable for use as a possible power source for silicon integrated circuits. We present further improved power generation performances of PZT MEMS acoustic energy harvesters fabricated by improved PZT capacitor fabrication processes. The PZT acoustic energy harvester with the diaphragm diameter of 1.2 mm fabricated by a sol/gel process generated an even higher energy density of 98 µW/m2under the sound pressure level of 100 dB (0.01 W/m2) at 16.7 kHz.
Fabrication of Focus-Variable Fluidic Microlens Using Single Casting
Authors: Dang Trung-Dung , Park Cheol-Woo , Kim Gyu-Man
Published: June 2011

An elastomeric microfluidic lens of variable focal length was fabricated by single casting from a microfabricated mold. The lens is a poly(dimethylsiloxane) (PDMS) microfluidic chamber covered with a thin membrane. By introducing fluid inside, the pressure varied in the microfluidic chamber, which produced a shift in the microlens focal plane resulting in a change in the back focal length of the lens. Hot pressing was used to fabricate the microfluidic chamber and membrane in a single body. The fabrication processes are simple, avoid handling difficulties of the thin membrane, and provide uniform thickness of the membrane, which essentially affect lens performance. The optical properties of the lens such as lens shape, back focal length, and numerical aperture were calculated and measured at various lens geometries and applied pressures. The back focal length of the lens changed approximately from 30 to 5 mm. The relationships of the optical properties, namely, back focal length and numerical aperture, with applied pressure were studied and verified using optical image tests. The variable focal length of the microfluidic lens is critical to increase the efficiency of light detection in optical or biophotonic applications.
Design and Fabrication of Highly Manufacturable Microelectromechanical Systems Test Sockets for Ball Grid Array Integrated Circuit Packages
Authors: Cho Chanseob , Kim Sangwon , Kong Daeyoung , Nam Jaewoo , Kim Bonghwan , Lee Jonghyun
Published: June 2011

We have developed two types of microelectromechanical systems (MEMS) test sockets for the ball grid array (BGA) integrated circuit (IC) packages. The fabricated MEMS test sockets have simple structures, easy fabrication processes, low contact forces, and rapid prototyping and cost-effective processes. In the case of the cantilever-array-type test socket, we optimized the length, width, and thickness of the cantilever appropriate for a 121 ball square BGA IC package test. The contact force is 1.3 mN (1 g force ≈ 1 mN) for each cantilever with a length of 425 µm, a width of 150 µm, and a thickness of 10 µm at a deflection of 100 µm. The mesh-type test socket has a different maximum deflection value in accordance with the contact position. The average contact resistance is 0.73 Ω and the maximum signal path resistance is 18 Ω for the two types of MEMS test sockets. The fabricated MEMS test sockets are suitable for an actual BGA IC package test.
Motor‐Evoked Potential Confirmation of Functional Improvement by Transplanted Bone Marrow Mesenchymal Stem Cell in the Ischemic Rat Brain
Authors: Jang Dong-Kyu , Park Sang-In , Han Young-Min , Jang Kyung-Sool , Park Moon-Seo , Chung Young-An , Kim Min-Wook , Maeng Lee-So , Huh Pil-Woo , Yoo Do-Sung , Jung Seong-Whan
Published: June 2011

This study investigated the effect of bone marrow mesenchymal stem cells (BMSCs) on the motor pathway in the transient ischemic rat brain that were transplanted through the carotid artery, measuring motor‐evoked potential (MEP) in the four limbs muscle and the atlantooccipital membrane, which was elicited after monopolar and bipolar transcortical stimulation. After monopolar stimulation, the latency of MEP was significantly prolonged, and the amplitude was less reduced in the BMSC group in comparison with the control group (P < .05). MEPs induced by bipolar stimulation in the left forelimb could be measured in 40% of the BMSC group and the I wave that was not detected in the control group was also detected in 40% of the BMSC group. Our preliminary results imply that BMSCs transplanted to the ischemic rat brain mediate effects on the functional recovery of the cerebral motor cortex and the motor pathway.
Controlled Aspect Ratios of Gold Nanorods in Reduction-Limited Conditions
Authors: Kim Jong-Yeob , Ah Chil Seong , Jang Du-Jeon
Published: June 2011

Aspect ratios of gold nanorods have been finely modified in reduction-limited conditions via two electrochemical ways: by changing the amount of a growth solution containing small gold clusters in the presence of already prepared gold nanorods as seeds or by changing electrolysis time in the presence or absence of a silver plate. While the atomic molar ratio of gold in the growth solution to gold in the seed solution is critical in the former method, the relative molar ratio of gold ions to silver ions in the electrolytic solution is important in the latter way for the control of the aspect ratios of gold nanorods. The aspect ratios of gold nanorods decrease with an increase of electrolysis time in the absence of a silver plate, but they increase with an increase of electrolysis time in the presence of a silver plate.
Frequent Loss of Genome Gap Region in 4p16.3 Subtelomere in Early-Onset Type 2 Diabetes Mellitus
Authors: Kudo Hirohito , Emi Mitsuru , Ishigaki Yasushi , Tsunoda Uiko , Hinokio Yoshinori , Ishii Miho , Sato Hidenori , Yamada Tetsuya , Katagiri Hideki , Oka Yoshitomo
Published: June 2011

A small portion of Type 2 diabetes mellitus (T2DM) is familial, but the majority occurs as sporadic disease. Although causative genes are found in some rare forms, the genetic basis for sporadic T2DM is largely unknown. We searched for a copy number abnormality in 100 early-onset Japanese T2DM patients (onset age <35 years) by whole-genome screening with a copy number variation BeadChip. Within the 1.3-Mb subtelomeric region on chromosome 4p16.3, we found copy number losses in early-onset T2DM (13 of 100 T2DM versus one of 100 controls). This region surrounds a genome gap, which is rich in multiple low copy repeats. Subsequent region-targeted high-density custom-made oligonucleotide microarray experiments verified the copy number losses and delineated structural changes in the 1.3-Mb region. The results suggested that copy number losses of the genes in the deleted region around the genome gap in 4p16.3 may play significant roles in the etiology of T2DM.
Uniqueness of Meromorphic Functions and Differential Polynomials
Authors: Li Jin-Dong
Published: June 2011

We study the uniqueness of meromorphic functions and differential polynomials sharing one value with weight and prove two main theorems which generalize and improve some results earlier
given by M. L. Fang, S. S. Bhoosnurmath and R. S. Dyavanal, and so forth.
Molecular Laser Spectroscopy as a Tool for Gas Analysis Applications
Authors: Nwaboh Javis Anyangwe , Desbois Thibault , Romanini Daniele , Schiel Detlef , Werhahn Olav
Published: June 2011

We have used the traceable infrared laser spectrometric amount fraction measurement (TILSAM) method to perform absolute concentration measurements of molecular species using three laser spectroscopic techniques. We report results performed by tunable diode laser absorption spectroscopy (TDLAS), quantum cascade laser absorption spectroscopy (QCLAS), and cavity ring down spectroscopy (CRDS), all based on the TILSAM methodology. The measured results of the different spectroscopic techniques are in agreement with respective gravimetric values, showing that the TILSAM method is feasible with all different techniques. We emphasize the data quality objectives given by traceability issues and uncertainty analyses.
Glucagon-Like Peptide-1 Gene Therapy
Authors: Rowzee Anne M. , Cawley Niamh X. , Chiorini John A. , Di Pasquale Giovanni
Published: June 2011

Glucagon-like peptide 1 (GLP-1) is a small peptide component of the prohormone, proglucagon, that is produced in the gut. Exendin-4, a GLP-1 receptor agonist originally isolated from the saliva ofH. suspectumor Gila monster, is a peptide that shares sequence and functional homology with GLP-1. Both peptides have been demonstrated to stimulate insulin secretion, inhibit glucagon secretion, promote satiety and slow gastric emptying. As such, GLP-1 and Exendin-4 have become attractive pharmaceutical targets as an adjunctive therapy for individuals with type II diabetes mellitus, with several products currently available clinically. Herein we summarize the cell biology leading to GLP-1 production and secretion from intestinal L-cells and the endocrine functions of this peptide and Exendin-4 in humans. Additionally, gene therapeutic applications of GLP-1 and Exendin-4 are discussed with a focus on recent work using the salivary gland as a gene therapy target organ for the treatment of diabetes mellitus.
A Data‐Guided Lexisearch Algorithm for the Asymmetric Traveling Salesman Problem
Authors: Ahmed Zakir Hussain
Published: June 2011

A simple lexisearch algorithm that uses path representation method for the asymmetric traveling salesman problem (ATSP) is proposed, along with an illustrative example, to obtain exact optimal solution to the problem. Then a data‐guided lexisearch algorithm is presented. First, the cost matrix of the problem is transposed depending on the variance of rows and columns, and then the simple lexisearch algorithm is applied. It is shown that this minor preprocessing of the data before the simple lexisearch algorithm is applied improves the computational time substantially. The efficiency of our algorithms to the problem against two existing algorithms has been examined for some TSPLIB and random instances of various sizes. The results show remarkably better performance of our algorithms, especially our data‐guided algorithm.
An Initial Investigation into the Use of a Flux Chamber Technique to Measure Soil-Atmosphere Gas Exchanges from Application of Biosolids to UK Soils
Authors: Donovan S. M. , Skartsila A. M. , Head M. K. , Voulvoulis N.
Published: June 2011

While a significant amount of work has been conducted to assess the concentration of pollutants in soils and waterways near land that has been amended with biosolids, a relatively small body of research investigating emissions to atmosphere is available in the literature. Some studies have indicated that while the CO2emissions from soils decrease with fertiliser application, the CH4and N2O emissions might be increased, offsetting the benefit. The objective of the research presented in this paper was to address this gap, by the use of a flux chamber technique to measure soil-atmosphere gas exchanges from the application of biosolids to land. This was done by applying three different types of biosolids to soils and measuring gases at the soil-atmosphere interface. The measurements were taken on areas with three different types of vegetation. The gases were collected using a flux chamber technique and analysed by gas chromatography. The results presented here are preliminary findings of an ongoing experiment. Insignificant variation appeared to occur between different areas of vegetation; however, small variations in gas concentrations were observed indicating a need for continued monitoring of soil-atmosphere gas exchanges to determine the long-term impacts on the atmosphere and the environment.
Selective Amygdalohippocampectomy
Authors: Spencer David , Burchiel Kim
Published: June 2011

Epilepsy surgery can be an effective epilepsy treatment for patients whose seizures do not respond to best medical therapy. For patients with temporal lobe epilepsy, selective amygdalohippocampectomy (SAH) has emerged as a viable alternative to standard anterior temporal lobectomy. This paper reviews the indications for SAH, the technical advances that have led to greater adoption of the procedure, the expectations for seizure control, and the risks of morbidity.
Terpinen-4-ol Induces Apoptosis in Human Nonsmall Cell Lung Cancer In Vitro and In Vivo
Authors: Wu Chieh-Shan , Chen Yun-Ju , Chen Jeremy J. W. , Shieh Jeng-Jer , Huang Chia-Hsin , Lin Pei-Shan , Chang Gee-Chen , Chang JingHua-Tsai , Lin Chi-Chen
Published: June 2011

Terpinen-4-ol, a monoterpene component of the essential oils of several aromatic plants, exhibits antitumor effects. In this study, the antitumor effects of terpinen-4-ol and the cellular and molecular mechanisms responsible for it were evaluated and studied, respectively on human nonsmall cell lung cancer (NSCLC) cells. Our results indicated that terpinen-4-ol elicited a dose-dependent cytotoxic effect, as determined by MTT assay. Increased sub-G1 population and annexin-V binding, activation of caspases 9 and 3, cleavage of poly(ADPribose) polymerase (PARP), and a decrease of mitochondrial membrane potential (MMP) indicated involvement of the mitochondrial apoptotic pathway in terpinen-4-ol-treated A549 and CL1-0 cells. Elevation of the Bax/Bcl-2 ratio and a decrease in IAP family proteins XIAP and survivin were also observed following terpinen-4-ol treatment. Notably, terpinen-4-ol was able to increase p53 levels in A549 and CL1-0 cells. Diminution of p53 by RNA interference induced necrosis instead of apoptosis in A549 cells following terpinen-4-ol treatment, indicating that terpinen-4-ol-elicited apoptosis is p53-dependent. Moreover, intratumoral administration of terpinen-4-ol significantly suppressed the growth of s.c. A549 xenografts by inducing apoptosis, as confirmed by TUNEL assay. Collectively, these data provide insight into the molecular mechanisms underlying terpinen-4-ol-induced apoptosis in NSCLC cells, rendering this compound a potential anticancer drug for NSCLC.
Potential Deleterious Effects of Vasopressin in Chronic Kidney Disease and Particularly Autosomal Dominant Polycystic Kidney Disease
Authors: Meijer E. , Boertien W.E. , Zietse R. , Gansevoort R.T.
Published: June 2011

The antidiuretic hormone vasopressin is crucial for regulating free water clearance in normal physiology. However, it has also been hypothesized that vasopressin has deleterious effects on the kidney. Vasopressin is elevated in animals and patients with chronic kidney disease. Suppression of vasopressin activity reduces proteinuria, renal hypertrophy, glomerulosclerosis and tubulointerstitial fibrosis in animal models. The potential detrimental influence of vasopressin is probably mediated by its effects on mesangial cell proliferation, renin secretion, renal hemodynamics, and blood pressure. In this review, we discuss the increasing body of evidence pointing towards the contribution of vasopressin to chronic kidney disease progression in general and to autosomal dominant polycystic kidney disease in particular. These data allude to the possibility that interventions directed at lowering vasopressin activity, for example by the administration of vasopressin receptor antagonists or by drinking more water, may be beneficial in chronic kidney disease.
Viral Stimuli Trigger Exaggerated Thymic Stromal Lymphopoietin Expression by Chronic Obstructive Pulmonary Disease Epithelium: Role of Endosomal TLR3 and Cytosolic RIG-I-Like Helicases
Authors: Calvén Jenny , Yudina Yulyana , Hallgren Oskar , Westergren-Thorsson Gunilla , Davies Donna E. , Brandelius Angelica , Uller Lena
Published: June 2011

Background: Rhinovirus (RV)-induced chronic obstructive pulmonary disease (COPD) exacerbations exhibit TH2-like inflammation. We hypothesized that RV-infected bronchial epithelial cells (BEC) overproduce TH2-switching hub cytokine, thymic stromal lymphopoietin (TSLP) in COPD. Methods: Primary BEC from healthy (HBEC) and from COPD donors (COPD-BEC) were grown in 12-well plates, infected with RV16 (0.5–5 MOI) or stimulated with agonists for either toll-like receptor (TLR) 3 (dsRNA, 0.1–10 µg/ml) or RIG-I-like helicases (dsRNA-LyoVec, 0.1–10 µg/ml). Cytokine mRNA and protein were determined (RTqPCR; ELISA). Results: dsRNA dose-dependently evoked cytokine gene overproduction of TSLP, CXCL8 and TNF-α in COPD-BEC compared to HBEC. This was confirmed using RV16 infection. IFN-β induction did not differ between COPD-BEC and HBEC. Endosomal TLR3 inhibition by chloroquine dose-dependently inhibited dsRNA-induced TSLP generation and reduced generation of CXCL8, TNF-α, and IFN-β. Stimulation of cytosolic viral sensors (RIG-I-like helicases) with dsRNA-LyoVec increased production of CXCL8, TNF-α, and IFN-β, but not TSLP. Conclusions: Endosomal TLR3-stimulation, by dsRNA or RV16, induces overproduction of TSLP in COPD-BEC. dsRNA- and RV-induced overproduction of TNF-α and CXCL8 involves endosomal TLR3 and cytosolic RIG-I-like helicases and so does the generation of IFN-β in COPD-BEC. RV16 and dsRNA-induced epithelial TSLP may contribute to pathogenic effects at exacerbations and development of COPD.
The Greening of the Gospel (and Black Body): Rev. Ike’s Gospel of Wealth and Post-Blackness Theology
Authors: Walton Jonathan L.
Published: June 2011

The purpose of this essay is to explore Rev. Ike’s particular form of positive confession theology and self-representation in relationship to his own professed post-black identity. By fusing the conversionist elements of his Pentecostal roots with the Spiritualist teachings of metaphysics and New Thought philosophy, Rev. Ike offered African Americans a theological vision of attaining material wealth while effacing what he and many of his followers regarded as the multiple negative cultural markers that blackness signified. This was not simply a theology that was preached from the pulpit; it was packaged and presented within media frames. Therefore, this essay will equally unveil and demystify the multiple aesthetic representations and conspicuous displays deployed by Eikerenkoetter, which reflect well-worn strategies on the part of the oppressed that connect understandings of citizenship and freedom with hyperconsumption.