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Home > News > A Sensitive And Dynamic Tactile Sensor Read more from Asian Scientist Magazine at: https://www.asianscientist.com/2017/04/tech/tactile-3d-active-matrix-sensor/ Abstract: Researchers from the Ulsan National Institute of Science and Technology (UNIST) have developed a three-dimensional sensor that can detect changes in pressure over four log scales. Their findings, published in Nature Communications, can be used to detect a wide range of pressures ranging from finger touch to the full body weight. Read more from Asian Scientist Magazine at: https://www.asianscientist.com/2017/04/tech/tactile-3d-active-matrix-sensor/


A recent study, affiliated with UNIST has developed a new technique to understand the correct architectures of IMM proteins, using special chemical tools. By solving the most difficult stage of new drug development, their work will help speed the development of new therapeutics and cures. This research has been led by the team of Professor Hyun-Woo Rhee of Chemistry at UNIST in collaboration with Professor Jong-Seo Kim at Center from the Center for RNA Research, within the Institute for Basic Science (IBS) at Seoul National University and Professor Jeong-Kon Seo of UNIST Central Research Facilities (UCRF). The results of the study have been appeared in the March 15th edition of the Journal of the American Chemical Society (JACS). IMM is one of the most active sites for cellular metabolism and it is deeply related for various human metabolic diseases including cancer and neurodegenerative diseases. Therefore, it is crucial to understand the correct architecture of the IMM proteome in live cells for successful and efficient development of mitochondria-targeted therapeutics. In the study, Professor Lee and his research team revealed the in vivo topological direction of 135 IMM proteins, using an in situ-generated desthiobiotin-phenoxyl radical probe with genetically targeted peroxidase (APEX). "The determination of membrane protein structure is one of the most challenging tasks in protein structure analysis," says Professor Lee. "Our identification of structural information on the mitochondrial inner-membrane proteome can provide valuable insights for the architecture and connectome of the IMM proteome in live cells." The research team designed a new chemical probe, desthiobiotin-phenol and applied it to the IMM proteins in live cells. Then, they identified the structure of membrane proteins via mass spectrometry (MS). Peroxidase can react with hydrogen peroxide to make the phenoxyl radical. Then, the phenoxyl radical can react with the tyrosine residue on the proximal protein forming a covalent bond. In the study, the research team obtained the topology information by analyzing the labeled tyrosine site of the membrane protein. The majority of protein sequence analysis today uses mass spectrometry (MS), which digests the protein sample into peptides using an appropriate enzyme. Previous analyses, which used genetically targeted ascorbate peroxidase (APEX), could not resolve structural identification because these analyses were based on unlabeled peptide detection. However, only the labeled peptide can provide useful structural information, according to the research team. Unlike biomolecules that are labeled with biotin-phenol, proteins and other targets that are labeled with desthiobiotin-phenol can be eluted without harsh, denaturing conditions. Moreover, as the number of available membrane protein structure samples obtained via MS increases, the efficiency of structural identification of membrane proteins also increases. Owing to the short lifetime of phenoxyl radicals generated in situ by submitochondrial targeted APEX and the impermeability of the IMM to small molecules, the solvent-exposed tyrosine residues of both the matrix and intermembrane space (IMS) sides of IMM proteins were exclusively labeled with the radical probe in live cells by Matrix-APEX and IMS-APEX, respectively and identified by mass spectrometry. Through this analysis, the research team confirmed 58 IMM protein topologies and determined the topological direction of 77 IMM proteins whose topology at the IMM has not been fully characterized. Explore further: Mapping the living cell: New technique pinpoints protein locations, helping scientists figure out their functions More information: Song-Yi Lee et al, Architecture Mapping of the Inner Mitochondrial Membrane Proteome by Chemical Tools in Live Cells, Journal of the American Chemical Society (2017). DOI: 10.1021/jacs.6b10418


News Article | April 25, 2017
Site: www.sciencedaily.com

Membrane proteins make up approximately a quarter of all gene products and are the targets of over 50% of all modern pharmaceutical drugs. The inner mitochondrial membrane (IMM) proteome plays a central role in maintaining mitochondrial physiology and cellular metabolism. Despite their importance, there has been no method to reveal the topology of mitochondrial membrane proteins in live cells, until now. A recent study, affiliated with UNIST has developed a new technique to understand the correct architectures of IMM proteins, using special chemical tools. By solving the most difficult stage of new drug development, their work will help speed the development of new therapeutics and cures. This research has been led by the team of Professor Hyun-Woo Rhee of Chemistry at UNIST in collaboration with Professor Jong-Seo Kim at Center from the Center for RNA Research, within the Institute for Basic Science (IBS) at Seoul National University and Professor Jeong-Kon Seo of UNIST Central Research Facilities (UCRF). The results of the study have been appeared in the March 15th edition of the Journal of the American Chemical Society (JACS). IMM is one of the most active sites for cellular metabolism and it is deeply related for various human metabolic diseases including cancer and neurodegenerative diseases. Therefore, it is crucial to understand the correct architecture of the IMM proteome in live cells for successful and efficient development of mitochondria-targeted therapeutics. In the study, Professor Lee and his research team revealed the in vivo topological direction of 135 IMM proteins, using an in situ-generated desthiobiotin-phenoxyl radical probe with genetically targeted peroxidase (APEX). "The determination of membrane protein structure is one of the most challenging tasks in protein structure analysis," says Professor Lee. "Our identification of structural information on the mitochondrial inner-membrane proteome can provide valuable insights for the architecture and connectome of the IMM proteome in live cells." The research team designed a new chemical probe, desthiobiotin-phenol and applied it to the IMM proteins in live cells. Then, they identified the structure of membrane proteins via mass spectrometry (MS). Peroxidase can make phenoxyl radical when react with hydrogen peroxide. Then, phenoxyl radical can react with tyrosine residue on the proximal protein forming covalent bond. In the study, the research team obtained the topology information by analyzing labeled tyrosine site of membrane protein. The majority of protein sequence analysis today uses mass spectrometry (MS), which digests the protein sample into peptides using an appropriate enzyme. Previous analyses, which used genetically-targeted ascorbate peroxidase (APEX) could not resolve structural identification because these analyses performed based on the unlabeled peptide detection. However, only labeled peptide can provide useful structural information, according to the research team. Unlike biomolecules that are labeled with biotin-phenol, proteins and other targets that are labeled with desthiobiotin-phenol can be eluted without harsh, denaturing conditions. Moreover, as the number of available membrane protein structure samples, obtained via MS increases, the efficiency of structural identification of membrane proteins also increases. Owing to the short lifetime of phenoxyl radicals generated in situ by submitochondrial targeted APEX and the impermeability of the IMM to small molecules, the solvent-exposed tyrosine residues of both the matrix and intermembrane space (IMS) sides of IMM proteins were exclusively labeled with the radical probe in live cells by Matrix-APEX and IMS-APEX, respectively and identified by mass spectrometry. Through this analysis, the research team confirmed 58 IMM protein topologies and determine the topological direction of 77 IMM proteins whose topology at the IMM has not been fully characterized.


News Article | May 2, 2017
Site: phys.org

Inkjet-printed batteries bring us closer to smart objects. Credit: Ulsan National Institute of Science and Technology (UNIST) The race is on to develop everyday objects that have network connectivity and can send and receive data: the so-called 'Internet of Things'. But this requires flexible, lightweight and thin rechargeable power sources. Currently available batteries are packaged into fixed shapes and sizes, making them unsuitable for many future needs. Researchers in South Korea have developed printable supercapacitors that can be incorporated into a wide variety of objects as a power source. The team, led by Professor Sang-Young Lee from Ulsan National Institute of Science and Technology, developed inks that can be printed onto paper to fabricate a new class of printed supercapacitors. The process involves using a conventional inkjet printer to print a preparatory coating—a 'wood cellulose-based nanomat'—onto a normal piece of A4 paper. Next, an ink of activated carbon and single-walled nanotubes is printed onto the nanomat, followed by an ink made of silver nanowires in water. These two inks form the electrodes. Finally, an electrolyte ink—formed of an ionic liquid mixed with a polymer that changes its properties when exposed to ultraviolet light—is printed on top of the electrodes. The inks are exposed at various stages to ultraviolet irradiation and finally the whole assembly is sealed onto the piece of paper with an adhesive film. The process results in a printed supercapacitor with good mechanical flexibility and reliable electrochemical performance. The team used the printed supercapacitor to make a 'smart glass' that responded to a temperature stimulus. The supercapacitor was printed onto the glass in the shape of the words 'hot' and 'cold'. When the glass was filled with hot or cold liquids, a red LED lamp lit up the word 'hot' or a blue LED lamp lit up the word 'cold' respectively. "Due to the simplicity and scalability of their process and design universality, [these] inkjet-printed supercapacitors … hold substantial promise as a new class of monolithically-integrated flexible power sources that are urgently needed for the forthcoming Internet of Things and flexible/wearable electronics," the researchers conclude in their paper published in the journal Energy & Environmental Science. Explore further: Heart-shaped Li-ion battery printed on a cup shows batteries can be printed almost anywhere


News Article | April 24, 2017
Site: www.eurekalert.org

(Ulsan National Institute of Science and Technology(UNIST)) A new study, affiliated with South Korea's Ulsan National Institute of Science and Technology (UNIST), introduced a new battery charging technology that uses light to charge batteries.


News Article | April 17, 2017
Site: www.eurekalert.org

A recent study, affiliated with UNIST has created a three-dimensional, tactile sensor that could detect wide pressure ranges from human body weight to a finger touch. This new sensor with transparent features is capable of generating an electrical signal based on the sensed touch actions, also, consumes far less electricity than conventional pressure sensors. The breakthrough comes from a research, conducted by Professor Jang-Ung Park of Materials Science and Engineering and his research team at UNIST. In the study, the research team presented a novel method of fabricating a transistor-type active-matrix pressure sensor using foldable substrates and air-dielectric layers. Today, most transistors are created with silicon channel and silicon oxide-based dielectrics. However, these transistors have been found to be either lacking transparency or inflexible, which may hinder their utility in fabricating highly-integrated pressure sensor arrays and transparent pressure sensors. In this regard, Professor Park's team decided to use highly-conductive and transparent graphene transistors with air-dielectric layers. The sensor can detect different types of touch-including swiping and tapping.. "Using air as the dielectric layer in graphene field-effect transistors (FETs) can significantly improve transistor performance due to the clean interface between graphene channel and air," says Professor Park. "The thickness of the air-dielectric layers is determined by the applied pressure. With that technology, it would be possible to detect pressure changes far more effectively." A convantional touch panel, which may be included in a display device, reacts to the static electrical when pressure is applied to the monitor screen. With this method, the position on screen contacted by a finger, stylus, or other object can be easily detected using changes in pressure, but can not provide the intensity of pressure. The research team placed graphene channel, metal nanowire electrodes, as well as an elastic body capable of trapping air on one side of the foldable substrate. Then they covered the other side of the substrate, like a lid and kept the air. In this transistor, the force pressing the elastic body is transferred to the air-dielectric layer and alters its thickness. Such changes in the thickness of the air-dielectric layer is converted into an electrical signal and transmitted via metal nanowires and the graphene channel, expressing both the position and the intensity of the pressure. This is regarded as a promising technology as it enables the successful implementation of active-matrix pressure sensors. Moreover, when compared with the passive-matrix type, it consumes less power and has a faster response time. It is possible to send and receive signals only by flowing electricity to the place where pressure is generated. The change in the thickness of the air dielectric layer is converted into an electrical signal to represent the position and intensity of the pressure. In addition, since all the substrates, channels, and electrode materials used in this process are all transparent, they can also be manufactured with invisible pressure sensors. "This sensor is capable of simultaneously measuring anything from lower pressure (less than 10 kPa), such as gentle tapping to high pressure (above 2 MPa), such as human body weight," says Sangyoon Ji (Combined M.S./Ph.D. student of Materials Science and Engineering), the first co-author of the study. "It can be also applied to 3D touchscreen panels or smart running shoes that can analyze life patterns of people by measuring their weight distribution." "This study not only solves the limitations of conventional pressure sensors, but also suggests the possibility to apply them to various fields by combining pressure sensor with other electronic devices such as display." says Professor Park. The results of the study have been published in the April issue of the journal Nature Communications, a sister journal of the prestigious Nature. It has been supported by the Ministry of Science, ICT & Future Planning (MSIP) and the Ministry of Trade, Industry and Energy (MOTIE) of Korea through the National Research Foundation. Shin, S.-H. et al. "Integrated Arrays of Air-Dielectric Graphene Transistors as Transparent, Active-Matrix Pressure Sensors for Wide Pressure Ranges", Nat. Commun. 8, (2017).


News Article | April 24, 2017
Site: www.rdmag.com

A new power source may lead to a quicker charge for portable electronics. A team of researchers from the Ulsan National Institute of Science and Technology (UNIST) in South Korea have developed a single-unit, photo-rechargeable portable power source that is designed to work under sunlight and indoor lighting, allowing users to power portable electronics anywhere with access to light. The power source is based on high-efficiency silicon solar cells and lithium-ion batteries (LIB). The single-unit PV-LIB device exhibits improved photo-electrochemical performance and its compact design lie beyond those achievable by conventional PVs or LIBs alone. The device was able to rapidly charge in less than two minutes with a photo-electric conversion/storage efficiency of 7.61 percent, a large improvement in photo-charging. The device, which uses a thin-film printing technique where the solid-state lithium ion battery is directly printed on the high-efficiency miniaturized crystalline Si photovoltaics (c-Si PV) module, represents a new class of monolithically integrated, portable PV-battery system based on miniaturized crystalline Si photovoltaics and printed solid-state lithium-ion batteries. “This device provides a solution to fix both the energy density problem of batteries and the energy storage concerns of solar cells,” professor Sang-Young Lee, said in a statement. “More importantly, batteries have relatively high power and energy densities under direct sunlight, which demonstrates its potential application as a solar-driven infinite energy conversion/storage system for use in electric vehicles and portable electronics.” Through an in-series printing process the researchers were able to fabricate a solid-state LIB with a bipolar cell configuration directly on the aluminum electrode of a c-Si PV module. The battery can be charged without the loss of energy because the researchers enabled the seamless architectural/electrical connection of the two different energy systems where the aluminum metal layer is simultaneously used as a current collector of the LIB as well as an electrode for solar cells. By inserting the SIPV-LIB device into a pre-cut credit card the researchers were able to fabricate a monolithically integrated smartcard. They then drew electric circuits on the back of the credit card using a commercial Ag pen to connect the device with an LED lamp and they also electrically connecting the device with a smartphone or MP3 player and explored its potential application as a supplementary portable power source under sunlight illumination. The device fully charged under sunlight illumination after just two minutes, while also showing ‘decent’ photo-rechargeable electric energy storage behavior even at high temperatures in extremely low light intensity. “The SiPV-LIB device presented herein shows great potential as a photo-rechargeable mobile power source that will play a pivotal role in the future era of ubiquitous electronics,” Lee said. The study was published in Energy & Environmental Science


News Article | April 24, 2017
Site: www.rdmag.com

A new power source may lead to a quicker charge for portable electronics. A team of researchers from the Ulsan National Institute of Science and Technology (UNIST) in South Korea have developed a single-unit, photo-rechargeable portable power source that is designed to work under sunlight and indoor lighting, allowing users to power portable electronics anywhere with access to light. The power source is based on high-efficiency silicon solar cells and lithium-ion batteries (LIB). The single-unit PV-LIB device exhibits improved photo-electrochemical performance and its compact design lie beyond those achievable by conventional PVs or LIBs alone. The device was able to rapidly charge in less than two minutes with a photo-electric conversion/storage efficiency of 7.61 percent, a large improvement in photo-charging. The device, which uses a thin-film printing technique where the solid-state lithium ion battery is directly printed on the high-efficiency miniaturized crystalline Si photovoltaics (c-Si PV) module, represents a new class of monolithically integrated, portable PV-battery system based on miniaturized crystalline Si photovoltaics and printed solid-state lithium-ion batteries. “This device provides a solution to fix both the energy density problem of batteries and the energy storage concerns of solar cells,” professor Sang-Young Lee, said in a statement. “More importantly, batteries have relatively high power and energy densities under direct sunlight, which demonstrates its potential application as a solar-driven infinite energy conversion/storage system for use in electric vehicles and portable electronics.” Through an in-series printing process the researchers were able to fabricate a solid-state LIB with a bipolar cell configuration directly on the aluminum electrode of a c-Si PV module. The battery can be charged without the loss of energy because the researchers enabled the seamless architectural/electrical connection of the two different energy systems where the aluminum metal layer is simultaneously used as a current collector of the LIB as well as an electrode for solar cells. By inserting the SIPV-LIB device into a pre-cut credit card the researchers were able to fabricate a monolithically integrated smartcard. They then drew electric circuits on the back of the credit card using a commercial Ag pen to connect the device with an LED lamp and they also electrically connecting the device with a smartphone or MP3 player and explored its potential application as a supplementary portable power source under sunlight illumination. The device fully charged under sunlight illumination after just two minutes, while also showing ‘decent’ photo-rechargeable electric energy storage behavior even at high temperatures in extremely low light intensity. “The SiPV-LIB device presented herein shows great potential as a photo-rechargeable mobile power source that will play a pivotal role in the future era of ubiquitous electronics,” Lee said. The study was published in Energy & Environmental Science


News Article | May 26, 2017
Site: www.eurekalert.org

The world's highest gain high power laser amplifier - by many orders of magnitude - has been developed in research led at the University of Strathclyde. The researchers demonstrated the feasibility of using plasma to amplify short laser pulses of picojoule-level energy up to 100 millijoules, which is a 'gain' or amplification of more than eight orders of magnitude - which could be likened to amplifying the sound of rustling leaves to that of a jumbo jet - in only two mm of plasma. They used 150 J pulses from the powerful Vulcan laser system at the Science and Technology Facilities Council's Central Laser Facility (CLF). Over the course of two pioneering experiments at the CLF, the scientists worked closely with CLF staff to adapt the Vulcan laser in order that two different colour lasers could exchange energy in a plasma. The measured gain coefficient of 180 cm-1 is more than 100 times larger than achievable from existing high power laser system amplifiers based on solid-state media. The results have been published in the journal Scientific Reports, in an article entitled An ultra-high gain and efficient amplifier based on Raman amplification in plasma. Professor Dino Jaroszynski, of Strathclyde's Department of Physics, led the research. He said: "Raman amplification in plasma is a fascinating concept that combines the ideas of Nobel Physics laureate CV Raman with plasma, optical and laser physics. Here, a relatively long, high-energy laser pulse is made to collide in plasma with a short, very low energy pulse. At the point where they collide they produce a beat wave, much like that of two colliding water waves. The light pressure of the beat pattern drives plasma electrons into a regular pattern or echelon that mimics the beat wave. This multi-layer echelon acts as a very high reflectivity, time-varying mirror that sweeps up the energy of the high energy pulse reflecting it into the low energy pulse, thus amplifying the low energy pulse and compressing its energy into an ultra-short duration pulse of light. "Our results are very significant in that they demonstrate the flexibility of the plasma medium as a very high gain amplifier medium. We also show that the efficiency of the amplifier can be quite large, at least 10%, which is unprecedented and can be increased further. However, it also shows what still needs to be understood and controlled in order to achieve a single stage high-gain, high-efficiency amplifier module. "One example of the challenges that we still face is how to deal with amplification of 'noise' produced by random plasma fluctuations, which is exacerbated by the extremely high gain. This leads to undesirable channels for the energy to go. We are making excellent progress and believe that we are in an excellent position to solve these problems in our next experimental campaigns." Dr Gregory Vieux who led the research team working at the CLF, said: "Plasma is a very attractive medium to work with. It has no damage threshold since it is already a fully broken-down medium, therefore we can use it to amplify short laser pulses without the need for stretching and re-compressing. Another advantage is that further compression during the amplification is theoretically possible. This could pave the way for the development of the next generation of laser systems delivering ultra-intense and ultra-short pulses and at a fraction of the cost of existing lasers. "Still, we are not quite there yet. The scheme relies on controlling the Raman instability. It has such a large growth factor that it can develop and grow from small plasma fluctuations." Laser amplifiers are devices that amplify light. In those that are familiar to us, this is done by synchronising the light emission from electrons in atoms or solid state matter, to make it coherent, which is a necessary step to achieving very high powers. However, very high power lasers at the frontier of technology are limited by damage to their optical components and amplifying media. This makes them very large and very expensive. Plasma, the ubiquitous medium of the universe, offers a way around this limitation because it is very robust and resistant to damage - plasma can be seen as matter that has already been broken down into its smallest constituent elements: electrons and ions. By harnessing waves in plasma we can dramatically reduce the size of laser amplifiers while providing a route to much higher peak powers than possible now, exceeding the petawatt range to possibly reach exawatts. This is a very worthy goal because very intense laser pulses can be used for fundamental studies, such as accelerating particles, helping drive nuclear fusion or even extracting particles from vacuum and recreating the conditions inside stars or the primordial condition of the universe in the laboratory. The highest power lasers in the world will be available for use at three research centres that are part of the European Extreme Light Infrastructure (ELI) project. This €850m project is dedicated to the study of light-matter interactions at the highest intensities and shortest time scales. The laser power at ELI will be 1016 Watts or 5% of the total sun's power that is absorbed on the earth at any time. These lasers will lead to new science and technology that could, for example, transform our understanding of high field physics and result in new radiotherapy modalities for the treatment of cancer. There is a need to reduce the cost of laser technology, which plasma could offer. Plasma may be a route to higher powers to go beyond those available at ELI to reach exawatt powers. The investigation was a collaboration between researchers from Strathclyde, Instituto Superior Técnico (IST) in Lisbon, Queens University Belfast, Ulsan National Institute of Science and Technology (UNIST) in South Korea, Heinrich Heine Universität, Düsseldorf and the Extreme Light Infrastructure in the Czech Republic. It was funded by the Engineering and Physical Sciences Research Council. The Research Excellence Framework 2014, the comprehensive rating of UK universities' research, ranked the University of Strathclyde's Physics research first in the UK, with 96% of output assessed as world-leading or internationally excellent.


News Article | May 15, 2017
Site: cen.acs.org

After a nuclear power plant accident, for safety reasons it can be difficult for humans or even robots to get close enough to the facility to assess the situation. To get accurate information without putting people or equipment at risk, responders would benefit from better technology to sense radioactive material from afar. That could come from high-power pulsed electromagnetic waves, reports a team from Ulsan National Institute of Science & Technology (UNIST). First proposed in 2010 by the University of Maryland’s Gregory S. Nusinovich and colleagues, the approach involves using an antenna to direct high-intensity millimeter or terahertz waves at a target area. If material there is radioactive, γ radiation or α particles ionize the surrounding air, releasing free electrons. The interaction of the antenna-directed electromagnetic waves and ionized air induces plasma formation, and the plasma in turn reflects the electromagnetic waves back to the source site for detection. The UNIST team, led by EunMi Choi, experimentally demonstrated detection of 0.5 µg of cobalt-60 from 120 cm away, the maximum distance allowed by the laboratory setup (Nat. Commun. 2017, DOI: 10.1038/ncomms15394). Off-the-shelf gyrotrons to generate the electromagnetic waves, antennae to direct them, and radio­frequency detectors could be used to deploy the technique for field detection. Depending on the equipment used, Choi believes the approach could scale to detect radioactivity at distances of at least tens of kilometers and possibly as far as 100 km. Because the time delay of plasma formation depends on γ emission energy, Choi also thinks the technique could be used to identify types of radioactive material.

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