High resolution photoemission spectroscopy with soft X-ray synchrotron radiation has been applied to montmorillonite, one of phyllosilicate compounds. Charge build-up is inevitable in the powder sample due to its insulating property so that photoemission peaks of element components are difficult to be assigned. On the other hand, photoemission peaks have been observed at their original peak positions without the charge shift. These non-shifted peaks enabled determination of binding energies of element components. Information on chemical bonding states of cesium, adsorbed artificially in the montmorillonite, has been also obtained.
The plasmonic chip which has wavelength-size grating pattern coated with a thin silver or gold film is applied to a sensitive biosensor because it can provide the enhanced fluorescence excited by the surface plasmon field. We have already reported on the sensitive immunodetection with the plasmonic sensor chip under the illumination system from top panel of a plasmonic chip. In this study, the structure of a biosensor chip was optimized for the illumination system from rear panel and the detection sensitivity of the system under the back illumination was compared with that for the other conditions including the top illumination system.
We propose the system to analyze water permeability through the lipid bilayer. The lipid bilayer suspended over microwells changes its shape when the difference of osmotic pressure is formed by solution exchange. When the solution concentration outside the microwell is lower than the inside, water permeates through the lipid bilayer membrane and bulges outward. The interference fringes observed in the suspended lipid bilayer allowed us to accurately analyze its structural changes. Water permeability through the lipid bilayer could be accurately estimated based on analysis of the changes in the interference fringes observed in the suspended lipid bilayer caused by the solution exchange.
The use of microwells sealed with lipid bilayers is promising for biodevices that utilize protein functions. We have fabricated microwell structures on a Si substrate sealed with lipid bilayers. We have investigated Ca2+ ion transport through α-hemolysin channels with fluorescent microscopy. However, problems remain as regards achieving the detection of smaller signal such as receptor channels. Ion leakage through the interfacial water layer between the lipid bilayer and the substrate is one of the major hurdles to be overcome. In this paper, we present the mechanism of the ion leakage behavior and then an improved microwell structure that uses bovine serum albumin coating on the device surface to prevent ion leakage from/into the microwells.
Mesenchymal stem cell (MSC) is known to show responsiveness to the physical properties, such as stiffness and nano- to micro-structures, of the extracellular environment. However, the signaling mechanism has not been fully elucidated yet. Here, the effects of nano-scale pillar arrays of the cell culture substrate on morphology and differentiation were evaluated in human MSC to understand the signaling mechanism in regulation of differentiation in response to the nano-scale structures. Human MSCs were cultured on a quartz substrate with the three types of pillar-arrays with 200 nm in side length, 150 nm in height, and different center-to-center spacings (300 nm, 400 nm, 700 nm) in a cell culture medium with no differentiation induction regent. The cells were well spread, and about half of the cells showed osteogenic differentiation on the flat region of the substrate. The spreading and the osteogenic differentiation were suppressed in the cells on the pillar-arrayed region regardless of the pillar spacing. This provided insight that the human MSCs spontaneously differentiate into the osteoblast in response to the stiff substrate with no structure, and the suppression of the cell spreading caused by the nano-scale structures can downregulate the progress of the osteogenic differentiation.
In this paper, we report on the development of a microfluidic device, which extract plasma from low volume whole blood (10 µL) aiming integration onto microfluidic system for micro analytical systems. The device autonomously performs separation of blood cells and transfer of separated plasma by steady rotation. Based on the original autonomous fluidic control theory, we developed the principle of automatic timed injection of pressurizing medium into the separation chamber. This realize transferring of separated plasma from blood separation chamber to other place, after separation blood cells by centrifugal force. When we demonstrated by the poly-dimethylsiloxane (PDMS) microfluidic device, it was confirmed that automatic plasma extraction was successfully implemented as designed. The efficiency of separation was evaluated from concentrations of blood cells in samples before and after extraction, and the rate of blood cells removal was 98.5%.
Gas cluster ion beam (GCIB) irradiation on polyether-ether ketone (PEEK) surface have been carried out to enhance the cell adhesion. GCIB creates nanostructures with size of 10 - 50 nm on PEEK surface. These nanostructures are effective to create hydrophilic PEEK surface. By irradiation of O2-GCIB on PEEK, increase of cell adhesion was observed. This cell adhesion enhancement was observed at oblique incidence, which indicates that GCIB irradiation is effective for three-dimensional structure.
Supported lipid bilayer (SLB) is one of artificial biomembrane systems for the studies of transportation reactions through biomembranes using solid devices and surface scientific methods. A key step in the SLB formation is transformation of spherical lipid vesicles to a planar membrane. We investigated stimulation methods for adsorbed lipid vesicles on a streptavidin-modified SiO2/Si substrate to induce tethered-type SLB. We describe the effects of osmotic stress, Ca2+ addition, and a freeze-thaw cycle on the adsorbed vesicles, and on the condition of t-SLB.
We report an improvement of the Plasma-on-Chip device that enables plasma irradiation to single cells. Dielectric barrier discharge (DBD) structure was introduced and power consumption was reduced to 200 µW. The modification extended the operation time of the Plasma-on-Chip device. As long as 10 min plasma irradiation to yeast cells, Saccharomyces cerevisiae was conducted.
This paper reports on the fabrication and demonstration of a novel autonomous centrifugal microfluidic dispenser that microchannels are patterned on the double side of the microchip. The dispenser executes metering of dispensing volume and injection into each target chamber. In a capillary dispenser that was previously reported is unstable, because liquids in the chambers during metering are kept by capillary force. However, the present double side patterning dispenser does not rely on capillary forces, owing to siphon valves, which three-dimensionally cross chambers and microchannels. In the experiments, it was confirmed that the double side patterning dispenser has a high accuracy of dispensing volume. Moreover, higher stability in repeatedly dispensing test was confirmed, in comparison with the capillary dispenser the. Therefore, it is expected to realize high stability and compact analytical systems, which are suitable for POCT, by integrating the dispenser on analytical devices.
We demonstrated a mixing of different density liquids via Euler-force. Euler-force is an inertial force by increase/decrease of angular acceleration on the rotational coordinate system. The mixing method can be universally utilized owing to very simple flow path structure and operation only by rotation control of the device. The method was not carried out about different density liquids, although performed about the same density liquids in previous research. In this study, it was investigated that the Euler-force mixing is also effective for different density liquids.
We demonstrate the on-chip synthesis of Au nanoparticles achieved by a microwave-induced reaction in a microfluidic channel. The chip structure consists of a waveguide and a microchannel through the inside of the waveguide. A post-wall waveguide, which configures the metallic post on the side wall continuously, is utilized to confine microwave fields. It allows to insert a solution inside the waveguide by microchannel passing between the metallic posts. In order to realize a miniaturization of the chip, the 24.125 GHz industrial, scientific, and medical (ISM) band is utilized instead of the commonly used 2.45 GHz ISM band. When pure water is heated in the microchannel under the microwave input power of 3.0 W, it has been confirmed that the temperature increases to 70℃. In this paper, this chip is adopted to synthesis Au nanoparticles via microwave-induced reaction. After the irradiation of the microwave power 3.0 W and the irradiation time 5 min, we have observed absorbance and dynamic light scattering of the reactant, and the results indicated generation of Au nanoparticles. This microwave synthesis system allows us to achieve automatic and fast selective synthesis of nanoparticles in the solution.
Recently, we can always shoot digital videos with smartphone and share them with family or friends after editing them. It is necessary to check whether they are tampered by someone or not, if we use these digital videos as forensic evidence in criminal investigation. This paper proposes a method for detecting tampered regions in a video where a specific subject is removed from a scene. In the proposed method, we use LSTM for the time domain analysis and U-Net for the space domain analysis. The detection accuracy achieved 0.98 in terms of F-measure, even though tampered region was deformed or moved in the video. The experimental results show superior performance to detect tampered regions for digital videos.
Target monitoring systems are widely used in various areas such as companies and schools for the prevention of crimes. Such systems require the operators to monitor the information sent from monitoring devices, such as cameras and/or beacon sensors. To reduce the burden on the operators, we have proposed an automatic target tracking system based on mobile agent technologies. The system succeeded in tracking targets when radio frequency identifier (RFID) sensors were used as monitoring devices. However, it sometimes resulted in target recognition errors when cameras were used. In this paper, we propose a method to address target recognition errors. In this method, an agent changes its behavior according to the distance calculated from pictures taken by a camera. We also validated our approach in terms of tracking accuracy through simulation.
This technical report shows a measurement technique for the complex permittivity of a dielectric thin film with the cylindrical resonator having sliding end plates in the millimeter wave region. In order to eliminate the influence of unwanted TM111 resonance mode which is frequently appeared on the response of TE011 for measurement of the dielectric thin film, the position of the end plates is adjusted adequately. The methodology and experimental results are presented to show the usefulness of this technique.