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Search Results: 1 - 10 of 686 matches for " Norihisa Miki "
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A Flexible Capacitive Sensor with Encapsulated Liquids as?Dielectrics
Yasunari Hotta,Yuhua Zhang,Norihisa Miki
Micromachines , 2012, DOI: 10.3390/mi3010137
Abstract: Flexible and high-sensitive capacitive sensors are demanded to detect pressure distribution and/or tactile information on a curved surface, hence, wide varieties of polymer-based flexible MEMS sensors have been developed. High-sensitivity may be achieved by increasing the capacitance of the sensor using solid dielectric material while it deteriorates the flexibility. Using air as the dielectric, to maintain the flexibility, sacrifices the sensor sensitivity. In this paper, we demonstrate flexible and highly sensitive capacitive sensor arrays that encapsulate highly dielectric liquids as the dielectric. Deionized water and glycerin, which have relative dielectric constants of approximately 80 and 47, respectively, could increase the capacitance of the sensor when used as the dielectric while maintaining flexibility of the sensor with electrodes patterned on flexible polymer substrates. A reservoir of liquids between the electrodes was designed to have a leak path, which allows the sensor to deform despite of the incompressibility of the encapsulated liquids. The proposed sensor was microfabricated and demonstrated successfully to have a five times greater sensitivity than sensors that use air as the dielectric.
Dynamic Characteristics of a Hydraulic Amplification Mechanism for Large Displacement Actuators Systems
Xavier Arouette,Yasuaki Matsumoto,Takeshi Ninomiya,Yoshiyuki Okayama,Norihisa Miki
Sensors , 2010, DOI: 10.3390/s100402946
Abstract: We have developed a hydraulic displacement amplification mechanism (HDAM) and studied its dynamic response when combined with a piezoelectric actuator. The HDAM consists of an incompressible fluid sealed in a microcavity by two largely deformable polydimethylsiloxane (PDMS) membranes. The geometry with input and output surfaces having different cross-sectional areas creates amplification. By combining the HDAM with micro-actuators, we can amplify the input displacement generated by the actuators, which is useful for applications requiring large deformation, such as tactile displays. We achieved a mechanism offering up to 18-fold displacement amplification for static actuation and 12-fold for 55 Hz dynamic actuation.
Effects of Micromachining Processes on Electro-Osmotic Flow Mobility of Glass Surfaces
Yosuke Koga,Reiko Kuriyama,Yohei Sato,Koichi Hishida,Norihisa Miki
Micromachines , 2013, DOI: 10.3390/mi4010067
Abstract: Silica glass is frequently used as a device material for micro/nano fluidic devices due to its excellent properties, such as transparency and chemical resistance. Wet etching by hydrofluoric acid and dry etching by neutral loop discharge (NLD) plasma etching are currently used to micromachine glass to form micro/nano fluidic channels. Electro-osmotic flow (EOF) is one of the most effective methods to drive liquids into the channels. EOF mobility is affected by a property of the micromachined glass surfaces, which includes surface roughness that is determined by the manufacturing processes. In this paper, we investigate the effect of micromaching processes on the glass surface topography and the EOF mobility. We prepared glass surfaces by either wet etching or by NLD plasma etching, investigated the surface topography using atomic force microscopy, and attempted to correlate it with EOF generated in the micro-channels of the machined glass. Experiments revealed that the EOF mobility strongly depends on the surface roughness, and therefore upon the fabrication process used. A particularly strong dependency was observed when the surface roughness was on the order of the electric double layer thickness or below. We believe that the correlation described in this paper can be of great help in the design of micro/nano fluidic devices.
Antithrombogenicity of Fluorinated Diamond-Like Carbon Films Coated Nano Porous Polyethersulfone (PES) Membrane
Gunawan S. Prihandana,Ippei Sanada,Hikaru Ito,Mayui Noborisaka,Yoshihiko Kanno,Tetsuya Suzuki,Norihisa Miki
Materials , 2013, DOI: 10.3390/ma6104309
Abstract: A nano porous polyethersulfone (PES) membrane is widely used for aspects of nanofiltration, such as purification, fractionation and dialysis. However, the low-blood-compatibility characteristic of PES membrane causes platelets and blood cells to stick to the surface of the membrane and degrades ions diffusion through membrane, which further limits its application for dialysis systems. In this study, we deposited the fluorinated-diamond-like-carbon (F-DLC) onto the finger like structure layer of the PES membrane. By doing this, we have the F-DLC films coating the membrane surface without sacrificing the membrane permeability. In addition, we examined antithrombogenicity of the F-DLC/PES membranes using a microfluidic device, and experimentally found that F-DLC drastically reduced the amount of blood cells attached to the surface. We have also conducted long-term experiments for 24 days and the diffusion characteristics were found to be deteriorated due to fouling without any surface modification. On the other hand, the membranes coated by F-DLC film gave a consistent diffusion coefficient of ions transfer through a membrane porous. Therefore, F-DLC films can be a great candidate to improve the antithrombogenic characteristics of the membrane surfaces in hemodialysis systems.
THALLIUM-201 SPECT FOR PULMONARY TUMORS
Norihisa Tonami
Iranian Journal of Nuclear Medicine , 1997,
Abstract: This study was undertaken to examine the ability of SPECT in differentiation of a pulmonary lesion suspecions of lung cancr. A total of 170 patients with suspected lung cancer were studied. A dose of Tl-201 chloride {148-296 MBq) was injected intravenously and tomographic early and delayed scans were obtained at 15 miniutes and 3 hours post injection, respectively. Delayed Tl-201 SPECT visulized all of the 147 malignant pulmonary lesions which were clearer than those obtained by the early SPECT. Tl-201 SPECT seems to be a useful method for assessing pulmonary tumors and it offeres the retention index useful for differentiating malignant from benign lesions, and mediastinal involvement from lung cancer.
Conjugated docosahexaenoic acid suppresses KPL-1 human breast cancer cell growth in vitro and in vivo: potential mechanisms of action
Miki Tsujita-Kyutoku, Takashi Yuri, Naoyuki Danbara, Hideto Senzaki, Yasuhiko Kiyozuka, Norihisa Uehara, Hideho Takada, Takahiko Hada, Teruo Miyazawa, Yutaka Ogawa, Airo Tsubura
Breast Cancer Research , 2004, DOI: 10.1186/bcr789
Abstract: KPL-1 cell growth was assessed by colorimetric 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay; cell cycle progression and mode of cell death were examined by flow cytometry; and levels of expression of p53, p21Cip1/Waf1, cyclin D1, Bax, and Bcl-2 proteins were examined by Western blotting analysis. In vivo tumor growth was examined by injecting KPL-1 cells subcutaneously into the area of the right thoracic mammary fat pad of female athymic mice fed a CDHA diet.CDHA inhibited KPL-1 cells more effectively than did DHA (50% inhibitory concentration for 72 hours: 97 μmol/l and 270 μmol/l, respectively). With both CDHA and DHA growth inhibition was due to apoptosis, as indicated by the appearance of a sub-G1 fraction. The apoptosis cascade involved downregulation of Bcl-2 protein; Bax expression was unchanged. Cell cycle progression was due to G0/G1 arrest, which involved increased expression of p53 and p21Cip1/Waf1, and decreased expression of cyclin D1. CDHA modulated cell cycle regulatory proteins and apoptosis-related proteins in a manner similar to that of parent DHA. In the athymic mouse system 1.0% dietary CDHA, but not 0.2%, significantly suppressed growth of KPL-1 tumor cells; CDHA tended to decrease regional lymph node metastasis in a dose dependent manner.CDHA inhibited growth of KPL-1 human breast cancer cells in vitro more effectively than did DHA. The mechanisms of action involved modulation of apoptosis cascade and cell cycle progression. Dietary CDHA at 1.0% suppressed KPL-1 cell growth in the athymic mouse system.The etiology of human breast cancer is complex and remains poorly understood. At least one-third of all human cancers may be associated with dietary factors [1]. In particular, it has been hypothesized that dietary fat intake plays a role in the development and progression of breast cancer. Evidence from very large prospective studies strongly suggests that there is no association between overall dietary fat intake and breast
Effect of Individual Differences in Construal Level on Procrastination: Moderating Role of Intelligence Theories  [PDF]
Miki Terada
Psychology (PSYCH) , 2017, DOI: 10.4236/psych.2017.84032
Abstract: The relationship between individual differences in construal level and self-control, including procrastination was investigated by examining the following hypotheses. 1) People with high level of construal would procrastinate less when learning a task than those with low level of construal; and 2) theories of intelligence would moderate the effect of construal level on procrastination. These hypotheses were tested by using survey data. Results indicated that people with a low construal level procrastinated more. Results also indicated the moderating role of intelligence theories on the relationship between Behavior Identification Form (BIF) score and procrastination. This study is expected to expand our understanding of construal level theory and individual differences. The findings are also expected to clarify the relationship between construal level and procrastination.
Impacts of Oceanic Preexisting Conditions on Predictions of Typhoon Hai-Tang in 2005
Akiyoshi Wada,Norihisa Usui
Advances in Meteorology , 2010, DOI: 10.1155/2010/756071
Abstract: We investigated the impact of variations in oceanic preexisting conditions on predictions of Typhoon Hai-Tang (2005) by using a coupled atmosphere-ocean model with 6-km horizontal resolution and providing the oceanic initial conditions on 12 July from 1997 to 2005 to the model. Variations in oceanic preexisting conditions caused variation in predicted central pressure of nearly 18 hPa at 72 h, whereas sea-surface cooling (SSC) induced by Hai-Tang caused a predicted central pressure difference of about 40 hPa. Warm-core oceanic eddies up to a few hundred kilometers across and a deep mixed layer climatologically distributed in the western North Pacific led to high mixed-layer heat potential, which increased latent heat flux, water vapor, and liquid water contents around Hai-Tang's center. These increases were closely associated with Hai-Tang's intensification. SSC negatively affected the eyewall, whereas variations in oceanic preexisting conditions remarkably affected spiral rainbands and the magnitude of SSC.
Impacts of Oceanic Preexisting Conditions on Predictions of Typhoon Hai-Tang in 2005
Akiyoshi Wada,Norihisa Usui
Advances in Meteorology , 2010, DOI: 10.1155/2010/756071
Abstract: We investigated the impact of variations in oceanic preexisting conditions on predictions of Typhoon Hai-Tang (2005) by using a coupled atmosphere-ocean model with 6-km horizontal resolution and providing the oceanic initial conditions on 12 July from 1997 to 2005 to the model. Variations in oceanic preexisting conditions caused variation in predicted central pressure of nearly 18?hPa at 72?h, whereas sea-surface cooling (SSC) induced by Hai-Tang caused a predicted central pressure difference of about 40?hPa. Warm-core oceanic eddies up to a few hundred kilometers across and a deep mixed layer climatologically distributed in the western North Pacific led to high mixed-layer heat potential, which increased latent heat flux, water vapor, and liquid water contents around Hai-Tang's center. These increases were closely associated with Hai-Tang's intensification. SSC negatively affected the eyewall, whereas variations in oceanic preexisting conditions remarkably affected spiral rainbands and the magnitude of SSC. 1. Introduction Advances in ocean data assimilation systems have enabled us to further understand tropical cyclone (TC) activity and the ocean response at weather-forecasting as well as seasonal to climate time scales. The relationships between TC activity and variations in the global ocean are of growing interest on seasonal to climate time scales. In contrast, TC-induced sea-surface cooling (SSC), the decrease in sea-surface temperature (SST) during and after the passage of a TC in general, is a well-known ocean response to a TC on a weather-forecasting scale. Previous studies reported that SSC varied depending on oceanic preexisting conditions [1] as well as on TC intensity and translation speed [2]. However, the dynamic and thermodynamic processes associated with SSC remain controversial [1, 3, 4] although vertical turbulent mixing and upwelling are known to be important [2]. According to our current understanding of the relationship between TC activity and ocean thermal forcing, not only SST but also temperature and salinity profiles in the upper ocean are important for determining TC intensity, whereas SSC slightly affects TC track prediction [5]. TC heat potential (TCHP), a measure of the oceanic heat content from the surface to the C isotherm depth (Z26), is highly correlated with TC intensity in the western North Pacific (WNP) on seasonal to climate time scales [6, 7]. TCs tend to rapidly intensify in the WNP when they pass over a region with a high TCHP and a deep Z26. Providing accurate oceanic preexisting conditions as oceanic initial
Cryptography and Algorithmic Randomness
Kohtaro Tadaki,Norihisa Doi
Computer Science , 2013,
Abstract: The secure instantiation of the random oracle is one of the major open problems in modern cryptography. We investigate this problem using concepts and methods of algorithmic randomness. In modern cryptography, the random oracle model is widely used as an imaginary framework in which the security of a cryptographic scheme is discussed. In the random oracle model, the cryptographic hash function used in a cryptographic scheme is formulated as a random variable uniformly distributed over all possibility of the function, called the random oracle. The main result of this paper is to show that, for any secure signature scheme in the random oracle model, there exists a specific computable function which can instantiate the random oracle while keeping the security originally proved in the random oracle model. In modern cryptography the generic group model is used also for a similar purpose to the random oracle model. We show that the same results hold for the generic group model. In the process of proving the results, we introduce the notion of effective security, demonstrating the importance of this notion in modern cryptography.
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