Language：English   Publishing type：Research paper (scientific journal)  

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Language：English   Publishing type：Research paper (scientific journal)  

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：MDPI  

DOI： 10.3390/mi12111403

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：MDPI  

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Elsevier B.V.  

DOI： 10.1016/j.sna.2021.113082

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：MDPI AG  

The small intestine has the majority of a host’s immune cells, and it controls immune responses. Immune responses are induced by a gut bacteria sampling process in the small intestine. The mechanism of immune responses in the small intestine is studied by genomic or histological techniques after in vivo experiments. While the distribution of gut bacteria, which can be decided by the fluid flow field in the small intestinal tract, is important for immune responses, the fluid flow field has not been studied due to limits in experimental methods. Here, we propose a microfluidic device with chemically fixed small intestinal tissue as a channel. A fluid flow field in the small intestinal tract with villi was observed and analyzed by particle image velocimetry. After the experiment, the distribution of microparticles on the small intestinal tissue was histologically analyzed. The result suggests that the fluid flow field supports the settlement of microparticles on the villi.

DOI： 10.3390/mi12060692

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Language：English   Publishing type：Research paper (international conference proceedings)  

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Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.3390/MI11050480

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Wiely  

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Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：電気学会  

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Language：English   Publishing type：Research paper (scientific journal)  

The small number of high-migratory cancer cells in a cell population make studies on high-migratory cancer cells difficult. For the development of migration assays for such cancer cells, several microfluidic devices have been developed. However, they measure migration that is influenced by microstructures and they collect not only high-migratory cells, but also surrounding cells. In order to find high-migratory cells in cell populations while suppressing artifacts and to collect these cells while minimizing damages, we developed a microfluidic high-migratory cell collector with the ability to sort cancer cells according to cellular migration and mechanical detachment. High-migratory cancer cells travel further from the starting line when all of the cells are seeded on the same starting line. The high-migratory cells are detached using a stretch of cell adhesive surface using a water-driven balloon actuator. Using this cell collector, we selected high-migratory HeLa cells that migrated about 100m in 12 h and collected the cells.

DOI： 10.3390/mi10020116

PubMed

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Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.3390/mi10010041

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PubMed

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Language：Japanese   Publisher：The Japan Society of Mechanical Engineers  

Enhancement of molecular binding improves the efficiency of screening for target cell-specific binding molecules. A channel for cell culture needs a height of more than 200 μm for healthy cell growth whereas a low channel enhances molecular binding. We developed a microfluidic device with variable channel height to switch the channel height in accordance with the culturing and binding steps of the screening. The molecular binding efficiency was evaluated by using fluorescence labeled antibodies. By switching the channel height, the average fluorescence brightness on the target cells was 3.5 times higher than that in a device without variable channel height.

DOI： 10.1299/jsmermd.2019.2p1-f08

CiNii Research

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Institute of Physics Publishing  

DOI： 10.1088/1361-6528/aac45c

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Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1088/1361-6528/aac45c

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Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1016/j.snb.2017.07.154

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Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.3390/mi7120224

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Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.3390/mi7090155

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PubMed

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Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1063/1.4939771

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Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.3390/mi6040409

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Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1016/j.sna.2014.11.007

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Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1021/nl5032502

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：IEEJ  

Spontaneous electromechanical oscillation is one of the major causes to shorten the lifetime of MEMS (micro-electro-mechanical systems) contact switches. In this study, we have experimentally visualized the spontaneous oscillation of a MEMS contact switch in the transmission electron microscope (TEM) chamber. We also have studied its behavior by crosschecking with a theoretical analysis based on a multi-physics model implemented on an electrical circuit simulator. Nanoscopic observation and analysis results suggested that a physical mechanism of the spontaneous oscillation is as follows: (i) Upon a voltage application to the actuator electrodes, the contact tips are mechanically brought into contact as an initial condition. (ii) When the voltage is reduced, the tips are retracted and a nanoscale gap is formed between the contact surfaces, where electrical charges are accumulated. (iii) The accumulated charges develop an electrostatic attractive force that pulls back the electrode surfaces into contact again, (iv) thereby instantly neutralizing the charges. (v) The surfaces of the equipotential lose the electrostatic attractive force, leading to the mechanical retraction of the surfaces. As the charges are repeatedly accumulated and dissipated, the electrostatic force is intermittently generated, leading to the cyclic sequence of pull-in, contact, and release that takes place at a fast rate of tens of kHz.

DOI： 10.1541/ieejsmas.134.338

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Language：Japanese   Publisher：高分子学会  

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Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1109/JMEMS.2013.2248123

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Language：Japanese   Publisher：日本トライボロジー学会 ; 1989-  

CiNii Books

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Language：Japanese   Publisher：The Surface Science Society of Japan  

For the better understanding of friction mechanism, it is important to study real contact points at the frictional interface. For this purpose, we originally built an experimental setup with micro electric mechanical system (MEMS) probes and a transmission electron microscope (TEM). Thanks to this setup, nanoscaled real contact points were formed and separated under <i>in-situ</i> TEM observation. The formation and the separation processes of real contact points were well visualized and those of silicon and gold real contact points were compared at the nanoscale.

DOI： 10.1380/jsssj.34.79

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Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1088/0957-4484/23/50/505701

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Language：English   Publishing type：Research paper (international conference proceedings)  

DOI： 10.1149/05007.0051ecst

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：IEEJ  

DOI： 10.1541/ieejsmas.133.98

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Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1038/srep00623

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Japanese Society of Tribologists  

We in-situ observed the deformation of a gold single real contact point at the nanoscale during friction experiment in order to reveal the mechanism of friction. In this experiment, a special experimental setup combining between micro-electro-mechanical system (MEMS) and transmission electron microscope (TEM), called MEMS-in-TEM, was utilized for the stable visualization of the real contact point. Gold tips with electrostatic actuators were gently brought into contact and were rubbed each other at a quasi-static speed under TEM observation. Between tips, the gold single real contact point was formed and deformed in shear. During this deformation, the ends of the real contact point travelled 2.8 nm along the surface of the gold tips, although those of silicon and silver did not move. The maximum friction was 60 nN, repeating the stick-slip behavior from 35 to 60 nN. This result will be helpful to understand the mechanism of friction at the nanoscale and the lubrication mechanism of solid lubricants.

DOI： 10.2474/trol.7.127

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Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1021/nl302379f

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Language：Japanese   Publisher：日本表面科学会  

For the further understanding of the material combination between silicon and gold, it is necessary to study silicon-gold interface at the nano scale. For this purpose, we originally built an experimental setup with a micro electric mechanical system (MEMS) probes and a transmission electron microscope (TEM). Thanks to this setup, nanoscaled interfaces were formed under <I>in-situ</I> TEM observation. At the nanoscaled silicon-silicon and gold-gold interfaces, nanocontacts were formed just with a mechanical contact and grown by the surface diffusion. At the interface between gold and silicon, gold and silicon diffused each other at room temperature. The activation energy to diffuse gold into silicon was 0.21 eV, which was matched well with those of bulk experiments.

DOI： 10.1380/jsssj.33.159

CiNii Books

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Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1063/1.3662180

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Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1088/0957-4484/22/35/355704

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Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1143/JJAP.50.077201

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Language：Japanese   Publisher：新樹社  

CiNii Books

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Language：English   Publisher：Japanese Society of Tribologists  

Observing the atomic-level deformation of a frictional interface in real-time is important step to elucidate the mechanism of lubrication. We have combined the nano-scale handling capabilities of MEMS technology with the unsurpassed observation ability of TEM and developed a MEMS-in-TEM experimental setup. Our MEMS device had Ag tips with two degree-of-freedom controlled by electrostatic actuators. Opposing tips were brought into contact using the actuator. After forming a contact, one tip was actuated laterally but slowly enough to maintain the contact between the tips. We succeeded in observing the nano-scale deformation of Ag junction in real time.

DOI： 10.2474/trol.6.226

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Language：English   Publishing type：Research paper (international conference proceedings)  

DOI： 10.1557/opl.2011.626

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Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1088/0957-4484/21/43/435705

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Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1063/1.3501987

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Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1088/0960-1317/20/7/075011

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Language：English   Publishing type：Research paper (international conference proceedings)  

DOI： 10.1088/1742-6596/258/1/012011

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Language：English   Publishing type：Research paper (international conference proceedings)  

DOI： 10.1149/1.3483501

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Language：English   Publishing type：Research paper (international conference proceedings)  

DOI： 10.1088/1742-6596/258/1/012005

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Language：English   Publishing type：Research paper (international conference proceedings)  

DOI： 10.1088/1742-6596/258/1/012004

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Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1088/0957-4484/20/6/065705

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Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1109/JMEMS.2006.885852

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Language：English   Publishing type：Research paper (international conference proceedings)  

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Language：English   Publishing type：Research paper (international conference proceedings)  

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Language：Japanese   Publisher：電気学会  

The approach-contact-deformation-fracture process at a gold nano contact using a micromachined device was successfully observed in a high resolution transmission electron microscope (HRTEM). MEMS opposing tips (a movable tip with a pair of electrostatic actuators and a fixed tip) was inserted into a HRTEM chamber. When the movable tip was approached to the fixed tip within 1 nm, gold nano contact was formed with 1 V bias voltage. The gold nano contact was thinned by retraction and finally fractured. The series of the formation, retraction and fracture were observed in an atomic scale.

DOI： 10.1541/ieejsmas.126.504

CiNii Books

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Language：Japanese   Publisher：[東京] : Institute of Electrical Engineers of Japan  

CiNii Research

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Other Link： https://ndlsearch.ndl.go.jp/books/R000000004-I027428371

Language：Japanese  

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Language：Japanese   Publisher：旭硝子財団  

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Language：Japanese   Publisher：The Surface Science Society of Japan  

ナノスケールの接触や剥離を調べるために、MEMS対向探針を透過電子顕微鏡の試料室内部に挿入し、対向探針の間で接触と剥離に関してその場観察を行った。シリコン対シリコや金対金、金対シリコンなどの材料系において、ナノスケールでの接触により真実接触点が形成され、その真実接触点が剥離するという摩擦のダイナミクスに重要な素過程について議論する。

DOI： 10.14886/sssj2008.32.0_15

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Language：Japanese   Publisher：東京大学生産技術研究所  

DOI： 10.11188/seisankenkyu.64.329

CiNii Books

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Language：English  

DOI： 10.1149/1.3700942

Web of Science

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Language：Japanese   Publisher：The Surface Science Society of Japan  

ナノサイズの機械デバイスにおいて摩擦は大きな力のひとつであり、摩擦はその性能を著しく低下させる大きな要因の一つである。そこで、講演者らは微小機械素子(MEMS)を透過型電子顕微鏡(TEM) 内部で駆動し、摩擦界面をナノスケールでその場観察する実験系、MEMS-in-TEMを開発した。本講演ではMEMS-in-TEMを用いて、様々な潤滑材料の摩擦界面をナノスケールで観察し、それと同時に摩擦力の測定を行った結果を発表する。

DOI： 10.14886/sssj2008.31.0.15.0

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Event date： 2020.10

Language：Japanese  

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Other Link： https://ndlsearch.ndl.go.jp/books/R000000004-I031480595

Event date： 2020.10

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Event date： 2020.10

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Event date： 2019.11

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Event date： 2019.11

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Event date： 2019.11

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Event date： 2019.11

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Event date： 2019.6

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Event date： 2019.6

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Event date： 2019.6

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<p>Enhancement of molecular binding improves the efficiency of screening for target cell-specific binding molecules. A channel for cell culture needs a height of more than 200 μm for healthy cell growth whereas a low channel enhances molecular binding. We developed a microfluidic device with variable channel height to switch the channel height in accordance with the culturing and binding steps of the screening. The molecular binding efficiency was evaluated by using fluorescence labeled antibodies. By switching the channel height, the average fluorescence brightness on the target cells was 3.5 times higher than that in a device without variable channel height.</p>

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Event date： 2019.3

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Event date： 2018.11

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Event date： 2018.10

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Event date： 2018.10

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Event date： 2018.10

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Event date： 2018.9

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Event date： 2018.6

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Event date： 2018.6

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Event date： 2018.6

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Event date： 2017.12

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Event date： 2017.11

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Event date： 2017.10

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Event date： 2017.5

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Event date： 2017.5

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<p>In order to find applicable target molecules for molecular target anti-cancer drugs, molecules on the surface of cancer cells in a peptide screening process should be close to those in a human body. A cancer spheroid is a cancer cell aggregate and shows properties similar to tissues. We previously proposed and achieved a peptide screening method using floating spheroids which stirs peptides and spheroids in a liquid slug using an internal convection to promote the peptide adhesion onto the spheroids. In this study, we investigate adhesion efficiency dependent on the speed of the liquid slug in the range from 7.2 to 31 mm/s. At a low speed (7.2 mm/s), antibodies as a simulation of a peptide do not adhere on the spheroids due to weak internal convection in the liquid slug. At a high speed (31 mm/s), the antibodies hardly adhered on the spheroids. We found the speed around 20 mm/s showed the efficient adhesion.</p>

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Event date： 2017.5

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Event date： 2017.5

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Event date： 2017.5

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&lt;p&gt;In order to find applicable target molecules for molecular target anti-cancer drugs, molecules on the surface of cancer cells in a peptide screening process should be close to those in a human body. A cancer spheroid is a cancer cell aggregate and shows properties similar to tissues. We previously proposed and achieved a peptide screening method using floating spheroids which stirs peptides and spheroids in a liquid slug using an internal convection to promote the peptide adhesion onto the spheroids. In this study, we investigate adhesion efficiency dependent on the speed of the liquid slug in the range from 7.2 to 31 mm/s. At a low speed (7.2 mm/s), antibodies as a simulation of a peptide do not adhere on the spheroids due to weak internal convection in the liquid slug. At a high speed (31 mm/s), the antibodies hardly adhered on the spheroids. We found the speed around 20 mm/s showed the efficient adhesion.&lt;/p&gt;

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Event date： 2017

Language：Japanese  

&lt;p&gt;Organic compounds produced by the photosynthesis of cyanobacteria are mostly consumed for the cyanobacterial division. We proposed a hypothesis that some cyanobacteria might increase the released organic compounds from the cyanobacteria when their divisions are suppressed. We previously developed a microfluidic device for culturing cyanobacteria under the suppression of their divisions, though it could not fully suppress the divisions of cyanobacteria. In order to solve this problem, the micro-pillars and the bottom of the channel were designed to be brought into contact, and the the chamber, where the divisions of cyanobacteria are suppressed, was isolated. The cyanobacteria in the chamber were well stored by micro-pillars both at the center and edge area for 24 hours.&lt;/p&gt;

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Event date： 2016.10

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Event date： 2016.10

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Event date： 2016.6

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Event date： 2016.6

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&lt;p&gt;We developed an automatic slug storage microfluidic device using hydrophobic passive valves. In order to measure temporal concentration change of cutaneous anesthesia with high temporal resolution, we previously developed a slug flow device, which can automatically split solutions into small droplets, and suppress mixing old and new solutions just within a slug. However, the many droplets should be stored in different reservoirs without fusing them together. For this purpose, automatic slug storage microfluidic device was necessary, and we achieved the device by using hydrophobic passive valves with different pressure barriers. Using this device, slugs were automatically stored in different reservoirs.&lt;/p&gt;

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Event date： 2016.6

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&lt;p&gt;We propose a micro-channel device to collect cancer cells with high migrating capability, which could cause metastasis. In order to collect cells attached on extracellular matrix, focal adhesions between cells and extracellular matrix should be broken. The desmosomes can be mechanically broken by using extension of cell culture surface. For this purpose, the device locally has a balloon under a cell culture surface. The extension rate of the cell culture surface is 40% with 300 μL water. Using the device, we could detach the high-migration cell, which has net displacement of 150 μm and total path of 250 μm, and collect it by the flow of cultural medium.&lt;/p&gt;

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Event date： 2016.6

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&lt;p&gt;Organic compounds produced by the photosynthesis of cyanobacteria are mostly consumed for the cyanobacterial division. We propose a hypothesis that the suppression of the cyanobacterial division might make cyanobacteria mutate themselves, and mutated cyanobacteria might release the organic compounds from their bodies to survive. To verify the hypothesis, we have to detect the organic compounds released from the cyanobacteria. For this purpose, large numbers of cyanobacteria should be cultured under the suppression of the division. We develop a microfluidic device with hydraulically-actuated micro-pillar array to trap large numbers of cyanobacteria and medium supply to culture cyanobacteria under an appropriate cultural condition. Using the microfluidic device, cyanobacteria are trapped by the micro-pillar array, and cultured to hundreds of cyanobacteria inside the space surrounded by micro-pillars, which might suppress cyanobacterial division due to high density of cyanobacteria.&lt;/p&gt;

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Event date： 2016.6

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<p>Peptides that can bind to normal cells should be removed in the screening of the tumor specific binding peptide. We developed a microfluidic device for screening of tumor specific binding peptide that has serially-connected chambers for normal cells and for cancer cells. The normal cell is to remove the non-specific binding peptides, and the cancer cell is to capture tumor specific binding peptides. Cell introduction into the chambers without cross-contamination and screening simulation using a fluorescence-labeled antibody are examined. In cell introduction experiment, contaminations of different types of cells were prevented. In the screening simulation, the trapped amount of the non-specific antibodies can be reduced to 46 % in the downstream chamber.</p>

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Event date： 2015.10

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Event date： 2015.10

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Event date： 2015.9

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Event date： 2015.5

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Cancer cells inside tumors are under low glucose and oxygen concentration, which increase the migration capability and are assumed to be an origin of cancer metastasis. However, the cellular level studies of cancer cells inside tumors are difficult due to the limitation of the conventional biological approaches, which cannot generate the conditions inside tumors. In order to overcome the difficulty, we design and fabricate a microfluidic device that can control the glucose and oxygen concentrations inside a micro chamber. We achieved the concentration gradients similar to the gradient inside a tumor.

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Event date： 2015.5

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Microdialysis is a method to continuously measure the chemical concentration near target areas inside a living being. However, the method needs more than 10 minutes to collect solutions including chemical materials, leading to the less temporal information of the chemical concentration. In order to obtain more precise temporal information, we develop a microfluidic device with a T-junction to generate a long slug flow. The collected solutions are to be measured with a mass-spectrometer, which needs 2 μL for the measurement in the required range for the chemical analysis. At 2 μL/min in flow rate of phosphate buffer solution (PBS) and silicone oil, the longest slugs were generated, corresponding to 24.2 sec. This duration is close to our target of 1min at 2 μL/min in flow rate of PBS, which may be achieved by connecting the slugs.

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Event date： 2014.12

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Event date： 2014.11

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Event date： 2014.11

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Event date： 2014.10

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Event date： 2014.5

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Cancer is the top leading cause of death in Japan. Anti-cancer drugs are one of the most popular treatments whereas they often have heavy side effects. Anti-cancer drugs with light or no side effects are under development using tumor specific binding peptides as guides to cancer cells. However, the number of candidate peptides for the tumor specific binding peptides are extremely large. An efficient peptide screening method is necessary to find them. For this purpose, we are developing a microfluidic device to uniformly disperse cancer cells into its micro chamber and screen the peptide form the large number of peptides. In this paper, we could uniformly disperse N87 cells into the micro chamber using a micro pillar array, and selectively trap yeasts with tumor specific binding peptides by N87 cells in the micro chamber.

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Event date： 2014.5

Language：Japanese  

Organic compounds produced by photosynthesis of cyanobacteria are mostly consumed for cyanobacterial growth and division. We propose a hypothesis that the suppression of the cyanobacterial growth and division may decrease the consumption of organic compounds and increase the storage. In order to verify this hypothesis, we develop a micro-pillar array to suppress the cyanobacterial growth and division. The micro-pillar allay has micro-scaled confined spaces where cyanobacteria photosynthesize. The cyanobacteria do not grow inside the confined spaces, while they do outside.

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Event date： 2013.11

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Event date： 2013.11

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Event date： 2013.11

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Event date： 2013.11

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Event date： 2013.6

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Event date： 2013.5

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Diffusion is important phenomena in biology such as cell-to-cell and intracellular communications. It is driven by Brownian motion, concentration distribution and turbulence flow. However, it gradually changes composition in liquid, which is important information of vital activities. In order to understand the vital activities, liquid containing such information should be stocked without changing its composition. Therefore, we developed a microfluidic device to archive the liquid suppressing the change of the composition. A liquid-liquid interface between two kinds of colored deionized water was observed inside a microchannel. A mixed region around the interface was not spread at the micro scale without any turbulence flow over 60 minutes.

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Event date： 2013.5

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Event date： 2013.5

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We developed a micro-whistle-type sensor driven by pneumatic pressure for the measurement of the applying force at the tip of a forceps in endoscopic surgery. The displacement applied to the sensor can be detected by the change of the resonant frequency of the whistle, which is controllable by the length of a resonant tube. It was fabricated using surface micromachining, resulting in the advantages: small size enough to be integrated into a forceps and capability of mass production. The standard deviation of the resonant frequency was 1.8 Hz and the magnitude of the sound was 83 dB. We obtained the proportional relationship between the length of the tube and the resonant frequency. Although these properties are comparable to our previous whistle-type sensor fabricated by a NC machine tool, it is proven that the MEMS based fabrication can produce a number of equal quality sensors.

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Event date： 2013.3

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Event date： 2013.3

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Event date： 2013.3

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これまでに我々のグループではTEMを用いてMEMSのシリコン対向探針で形成した単一真実接触部の凝着・せん断現象の直視観察に成功しているが、せん断過程の動力学には未だ不明な点が多い。そこで先ず、一定速度のせん断過程の分子動力学シミュレーションを行い、得られた真実接触部の形状とせん断力の時間変化を実験と比較する。次に走査速度を変化させて、せん断力の走査速度依存性や接触径の待機時間依存性を議論する。

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Event date： 2013

近年、機械デバイスの微細化により、微視的スケールの摩擦・摩耗現象を解明する必要性が増している。我々は、実験グループが行ったシリコンナノ接合のせん断測定を、真実接触部の摩耗の素過程として捉えてそのメカニズムの数値的な解明を試みる。分子動力学法を用いてシリコン対向探針の衝突・せん断過程を繰り返してシミュレートし、せん断力・探針の形状・エネルギーの間の関係に着目して、ナノスケール摩耗機構を議論する。

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Event date： 2013

Language：Japanese  

It is extremely important to understand material properties at micro/nano scale. For this purpose, we developed in-situ nanoscopic visualization system combining with micro-electro-mechanical systems (MEMS) and transmission electron microscope (TEM). Silicon opposing tips with MEMS actuators were brought into contact and formed a nanocontact at the contact point under TEM observation. The silicon nanocontact was retracted at the quasi-static speed, resulting in the super plastic elongation. This nanoscaled property of silicon was analysed by molecular dynamics method. The structure of silicon nanocontact was the mixture of nanoscaled crystal domains and amorphous interlayers. By this hybrid structure, this super plasticity was realized.

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Event date： 2012.10

Language：English  

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Event date： 2012.10

Language：English  

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Event date： 2012.9

Language：English  

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Event date： 2012.9

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Event date： 2012.9

Language：Japanese  

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Event date： 2012.7

Language：English  

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Event date： 2012.5

Language：English  

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Event date： 2012

近年、機械デバイスの微細化によりナノスケールでの摩耗の現象解明が必要とされている。本研究は、実験グループが先行しているシリコン探針のせん断過程を摩耗現象と捉えて、摩耗の数値的な解明を試みる。分子動力学法を用いてシリコン対向探針の衝突・せん断過程を繰り返してシミュレートし、せん断力、探針の形状、原子の結合エネルギーの関係に着目して、シリコンのナノスケールでの摩耗特性を議論する。

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Event date： 2012

これまでに我々のグループではTEMを用いてMEMSのシリコン対向探針接触界面での凝着・せん断現象の直視観察に成功しているが、せん断過程におけるナノコンタクト（接合部）の形状変化のメカニズムには未だ不明な点が多い。そこで、せん断過程の分子動力学シミュレーションを行い、せん断過程から破断に至るまでの接合部の形状変化（接合角度、接合径の変化）を評価し、実験測定の結果と比較したので報告する。

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Event date： 2011.7

Language：Japanese  

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Event date： 2011

Language：English  

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Event date： 2010.6

Language：English  

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Event date： 2010

Language：Japanese  

Diamond-Like Carbon (DLC) can have a high mechanical hardness, very low coefficient of friction, high wear resistance and chemical inertness. Because of these useful characteristics, special attention has been paid attention to the tribological study of the DLC. Recently, the target scale of the tribological research on the DLC inter facial layer reached down to nano scale. These research activities, however, have not achieved the real time observation of the DLC contact layers yet. Therefore, we have the combined precise motion controllability of MEMS technology with the high resolution imaging of TEM. In this experiment, we have achieved the in-situ observation of the stick-slip motion between DLC interfacial layers. We have also attained the measurement of the frictional force between the DLC surfaces.

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Event date： 2010

Language：Japanese  

Observing real time deformation at the atomic-scale has been a great challenge because of the difficulty in both formation and observation of nano-contacts. We have combined nano-scale handling capabilities of MEMS technology with the supreme observation ability of TEM and developed a MEMS-in-TEM experimental setup. Our MEMS device had Ag tips controlled by electrostatic actuators. Opposing tips were brought into contact using the actuator. After achieving the contact, Ag-coated opposing tip was actuated in lateral direction while maintaining the contact. We succeeded in observing the deformation of the frictional interface at the boundaries of the gliding grains. Furthermore, we have observed that the interface was reorganized because of the dislocated strain.

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Event date： 2010

Language：Japanese  

The deformation on the surface of the gold MEMS opposing tips was observed with a transmission electron microscope. A gold nanocontact was formed between the tips, resulting in 92 μA under 1 V in bias voltage. And then, the nanocontact was separated with the retraction using MEMS actuators. After the breakage of the gold nanocontact, the tip was vibrated and performed the cyclic contact/separation experiment. The shape of the tip were initially sharpened from 1.3 nm up to 0.6 nm in radius curvature at 17 millicon times and finally flattened to 4.1 nm at 17.7 millicon times.

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Event date： 2010

Language：Japanese  

A real contact point at the nanoscale between silicon tips was observed during a frictional motion using MEMS-in-TEM system. The contact point was plastically deformed between silicon MEMS tips driven by electrostatic actuators. The deformation was divided into two parts ; (1) shear deformation and rotation of the silicon contact point, and (2) tensile deformation of the silicon contact point. In the shear and rotation phase, the force applied to the silicon contact point was less than 100 nN. When the phase moved from (1) to (2), the force was increased. The maximum force applied to the silicon contact point was 336 nN in the tensile phase. Therefore, the force during the frictional motion was caused in the tensile phase.

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Event date： 2009.7

Language：Japanese  

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Event date： 2009

Language：English  

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Event date： 2009

Language：English  

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Event date： 2008.6

Language：Japanese  

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Event date： 2007.7

Language：Japanese  

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Event date： 2007

Language：Japanese  

It is necessary to study the characteristics of materials in atomic scale because electric devices are scaling down to nanometer size. In nano scale, the peculiar structures and phenomena on the surface of materials ware observed. Nano-contact is one of the important atomic scale structures to investigate such nano scopic phenomena. In this paper, a MEMS (Micro Electro Mechanical System) device with movable opposing tips was fabricated to observe nano-contact. This device is actuated electrostatically in the transmission electron microscope (TEM). And tilt-evaporation which can make hetero-material opposing tips was proposed and inspected.

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Event date： 2007

Language：English  

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Event date： 2007

Language：Japanese  

我々の開発したMEMSのシリコン対向探針を接近、引き離しさせる事により、シリコン接合の形成が見出されているが、接合の詳細な結晶構造は不明である。そこで、シリコン対向探針の破断における動力学を数値シミュレーションによって、解析する。先ず構造最適化の方法によって、断熱極限での力曲線と構造を計算する。次に各安定構造に有限温度の分子動力学を適用して破断の詳細を調べる。

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Event date： 2007

Language：English  

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Event date： 2005

Language：English  

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Event date： 2004.2

Language：Japanese  

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Event date： 2004

Language：English  

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Language：English   Presentation type：Poster presentation  

Venue：Tokyo  

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Language：Japanese   Presentation type：Poster presentation  

Venue：福岡県  

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Language：Japanese   Presentation type：Poster presentation  

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Language：Japanese   Presentation type：Oral presentation (general)  

Venue：東京  

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Language：Japanese   Presentation type：Oral presentation (general)  

Venue：東京  

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Language：Japanese   Presentation type：Poster presentation  

Venue：福岡  

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Language：Japanese   Presentation type：Oral presentation (general)  

Venue：宮城  

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Language：Japanese   Presentation type：Oral presentation (general)  

Venue：宮城  

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Language：Japanese   Presentation type：Poster presentation  

Venue：東京  

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Language：Japanese   Presentation type：Oral presentation (general)  

Venue：静岡  

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Language：Japanese   Presentation type：Oral presentation (general)  

Venue：静岡  

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Language：Japanese   Presentation type：Oral presentation (general)  

Venue：静岡  

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Language：Japanese   Presentation type：Oral presentation (general)  

Venue：宮城  

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Language：Japanese   Presentation type：Oral presentation (general)  

Venue：静岡  

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Language：Japanese   Presentation type：Oral presentation (general)  

Venue：山口  

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Audience： Civic organization

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Audience： Schoolchildren

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Audience： Company

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Audience： General,　Company

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Audience： General

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Audience： General

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Audience： Junior students

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Audience： General

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Audience： General

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Audience： General

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Audience： Schoolchildren

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Audience： High school students

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Audience： General

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