본문 바로가기
대메뉴 바로가기
KAIST
Newsletter Vol.24
Receive KAIST news by email!
View
Subscribe
Close
Type your e-mail address here.
Subscribe
Close
KAIST
NEWS
유틸열기
홈페이지 통합검색
-
검색
KOREAN
메뉴 열기
Science
by recently order
by view order
KAISTian of the Year 2016: Professor Hee-Sung Park
Professor Hee-Sung Park of the Department of Chemistry has been named the KAISTian of 2016. President Sung-Mo Kang awarded him at the New Year ceremony on January 2, 2017. The KAISTian of the Year recognizes the most outstanding professor whose research and scholarship made significant achievements for the year. The Selection Committee announced that Professor Park was chosen as the 16th awardee in recognition of his developing new methods to incorporate unnatural amino acids into proteins. Earning his Ph.D. in chemical engineering at KAIST in 2000, Professor Park has been a professor at KAIST since 2009. His research focuses on the production of synthetic proteins and the generation of diverse protein functions as well as the designing and engineering of new translation machinery for genetic code expansion, and the application of synthetic biology techniques for basic cell biology and applied medical science. He developed a tool to engineer designer proteins via diverse chemical modifications, providing a novel platform for investigating numerous diseases such as cancer and dementia. Post-translational modifications (PTMs) are constantly taking place during or after protein biosynthesis. PTMs play a vital role in expanding protein functional diversity and, as a result, critically affect numerous biological processes. Abnormal PTMs have been known to trigger various diseases including cancer and dementia. Therefore, this technology, that enables proteins to reproduce with specific modifications at selected residues, will significantly help establish experimental strategies to investigate fundamental biological mechanisms including the development of targeted cancer therapies. Professor Park’s research results appeared in the September 28, 2016 edition of Science. For more on Professor Park's research, please visit: http://kaistcompass.kaist.ac.kr/?issues=fall-2016&magazine=a-chemical-biology-route-to-site-specific-authentic-protein-modifications http://science.sciencemag.org/content/early/2016/09/28/science.aah4428 http://www.kaist.ac.kr/html/en/news/podcast.html (Podcast: Season 6 Episode 7: When good proteins go bad )
2017.01.10
View 6640
Science, IT & Culture Volunteering Team at Cambodia
The Science, IT and Culture Volunteering Team, which is composed of 17 undergraduates, is visiting Cambodia January 1 to 16. Based at Hosanna High School in Phnom Penh, the KAIST volunteering team will participate in diverse science and IT classes as well as cultural events for Cambodian high school students. The KAIST volunteering service is designed to improve Cambodian students’ science education including the areas of physics, chemistry, biology, earth science, as well as an increased exposure to IT technologies. For this service, the volunteering team has prepared for three months, making syllabi for the science classes in addition to planning Arduino IT classes and cultural performances, including K-pop dances and Korean traditional games. The team will present various science experiments including smart electric fan and mini vehicles using Arduino. Before departing, the students made great efforts to ensure this service would be a success by taking a basic Khmer language class and studying safety education. Se-Woong Oh, the head of the team said, "All our members are very excited to have the chance to share our knowledge with Cambodian students and help them learn science and IT technology. We hope this service will serve as an opportunity to understand a different culture as well. We made every effort to prepare for an activity we believe in." (KAIST volunteer team with Hosanna High School students in Phnom Penh, Cambodia.)
2017.01.10
View 3894
Controlling DNA Orientation Using a Brush
Professor Dong Ki Yoon’s research team in the Graduate School of Nanoscience and Technology has developed a technique for producing periodic DNA zigzag structures using a common make-up brush. The results of the research, first-authored by Ph.D. student Yun Jeong Cha and published in Advanced Materials (online, November 15, 2016), has been highlighted in the hot topics of “Liquid Crystals.” There exist various methods for synthesizing DNA-based nanostructures, but they commonly involved complex design processes and required expensive DNA samples with regulated base sequences. Using DNA materials extracted from salmon, the research team was able to produce a nanostructure with a well-aligned zigzag pattern at one-thousandth of the usual cost. The team used a commercial make-up brush bought at a cosmetics store, and with it, applied the salmon DNA in one direction onto a plate, in the same way paint is brushed onto paper. Using a brush with a width of several centimeters, the team aligned DNA molecules of 2 nanometers in diameter along the direction of the brush strokes. As the thin and dense film of DNA came into contact with air, it lost moisture. An expansive force was created between the dried film and the plate. This force interacted with the elastic force of DNA and caused undulations in the uni-directionally aligned DNA molecules, which resulted in a regular zigzag pattern. The zigzag DNA’s base sequences could not be controlled because it was extracted from biological sources. However, it has the advantage of being cheap and readily available without compromising its structural integrity and provides a very regular and intricate structure. This kind of well-ordered DNA structure can be used as template because it can guide or control versatile guest functional materials that are applied to its surface. For example, it can align liquid crystals used in displays, as well as metallic particles and semi-conductors. It is expected that this capacity can be extended to optoelectric devices in the future. Professor Yoon remarked that “these findings have special implications, as they have demonstrated that various materials in nature aside from DNA, such as proteins, muscle cells, and components of bones can be applied to optoelectric devices.” This research has been carried out with the support of the Korea National Research Foundation’s Nanomaterials Fundamental Technology Development Program and the Pioneer Research Center under the High-tech Convergence Technology Development Program. Source: "Control of Periodic Zigzag Structures of DNA by a Simple Shearing Method" by Yun Jeong Cha and Dong Ki Yoon (Advanced Materials, November 15, 2016, DOI: 10.1002/adma.201604247) Figure 1. Diagram showing the well-ordered zigzag structure of DNA, and the internal molecular orientation Figure 2. (Left) Unaligned DNA (Right) Aligned DNA after being brushed and dried Figure 3. Control of the periodicity of the DNA zigzag patterns using micro-channel plates Figure 4. Diagram representing the control of orientation of liquid crystal materials applied on a zigzag DNA template, and a polarized optical microscope image
2017.01.10
View 5928
Nobel Laureate Dr. John Michael Kosterlitz Speaks at KAIST
KAIST’s Department of Physics will invite one of three co-recipients of the Nobel Prize in Physics 2016, Professor John Michael Kosterlitz of Brown University, on January 9, 2017, to speak about the exotic states of matter, which is entitled “Topological Defects and Phase Transitions.” Professor Kosterlitz shares the Nobel award with two other researchers, David Thouless and Duncan Haldane. He is considered one of the pioneers in the field of topological phases. In the early 1970s, along with Thouless, he demonstrated that superconductivity could occur at low temperatures and explained the mechanism behind, phase transition, that makes superconductivity disappear at higher temperatures. Over the last decade, topological materials and their applications have been widely studied with the hope of using them in new generations of electronics and superconductors, or in future quantum computers. Details of the lecture follow below: Distinguished Lecture Series by KAIST’s Physics Department · Speaker: Professor John Michael Kosterlitz of the Physics Department, Brown University · Topic: “Topological Defects and Phase Transitions” · Date: January 9, 2017, 4:00 PM · Place: Lecture Hall (#1501), College of Natural Sciences (E6-2)
2017.01.06
View 5462
The Antibody That Normalizes Tumor Vessels
Researchers also discover that their antisepsis antibody reduces glioma, lung and breast cancer progression in mice. A research team at the Center for Vascular Research within the Institute for Basic Science (IBS) discovered that the antisepsis antibody ABTAA (Ang2-Binding and Tie2-Activating Antibody) reduces tumor volume and improves the delivery of anti-cancer drugs. Published in Cancer Cell, this study demonstrates that ABTAA restores the structural and functional integrity of tumor blood vessels in three different tumor models: breast, lungs, and brain. Blood vessels inside and around an established tumor can be described as a chaotic and dysfunctional labyrinth. While the inner walls of healthy blood vessels are surrounded and supported by endothelial cells and other cells called pericytes, in the established tumor, the endothelial junctions are broken apart and pericytes are also detached. Blood flow into and from the tumor is severely retarded and tumor vessels lacking an intact vessel wall become leaky. This microenvironment causes limited drug delivery to the tumor and leads to inadequate oxygen supply (hypoxia) and even metastasis. The research team led by Professor Gou-Young Koh at KAIST’s Graduate School of Medical Science and Engineering found that the antibody ABTAA normalizes the tumor vessels and hence, change the whole tumor microenvironment. “We call it normalization of tumor vessels, because it resembles closely the wall architecture of healthy, normal vessels,” explains PARK Jin-Sung, first author of the study. And continues: “Tumor can adapt to hypoxia and get more aggressive, so we tried to prevent this transition by normalizing tumor vessels. ABTAA changes the whole tumor environment, oxygenation status and level of lactate, so that the immune cells and drugs can reach the core regions of the tumor more easily. In this way, we create a favorable ground for tumor treatment.” In an attempt to generate antibodies targeting the protein Ang2, which is specifically expressed by endothelial cells in stressful conditions like in tumor, the team unexpectedly discovered that ABTAA has a peculiar way of working and a dual function. ABTAA indeed not only blocks Ang2, but also activates Tie2 at the same time. Tie2 is a receptor present on the cell membrane of endothelial cells. ABTAA causes Ang2 to cluster together and to strongly activate Tie2 receptors. “If we activate Tie2, we can efficiently normalize tumor vessels, enhance drug delivery and change the whole microenvironment,” explains KOH Gou Young, Director of the Center for Vascular Research. Several pharmaceutical companies are developing Ang2-blocking antibodies to cure cancer. However, even if these antibodies significantly inhibit tumor progression, they do not stop tumor hypoxia. Moreover, most of the anti-cancer drugs target the tumor at its early stage, when tumors are still hard to diagnose. ABTAA, instead, works with tumors that are already rooted: “When the tumor is established, hypoxia is the main driver of tumor progression. So, if we eliminate hypoxia, we make the tumor milder, by reducing its progression and metastasis,” comments Koh. Figure: Schematic drawing of a blood vessel around tumors before and after treatment with ABTAA. The picture above shows a typical tumor vasculature characterized by damaged walls, red blood cells leakage and detached pericytes. Activating Tie2 on endothelial cells with the antibody ABTAA restores the normal vessel architecture: endothelial and pericytes on the vessel walls are stabilized, the delivery of blood is improved, and the anticancer drugs are more likely to reach the tumor core. The researchers tested ABTAA in mice with three different types of tumors that show high levels of Ang2: glioma (a type of a brain tumor), lung carcinoma, and breast cancer. They also compared the effect of ABTAA with ABA, another antibody that blocks Ang2 but misses the Tie2 activating properties. In all three cases, ABTAA was superior to ABA in inducing tumor vessel normalization, which led to a better delivery of the anti-cancer drugs into the tumor core region. Glioma is one of the so-called intractable diseases, because of its poor prognosis and treatment. Professor Koh’s team found that the glioma volume was reduced 39% by ABTAA and 17% by ABA. ABTAA profoundly reduced vascular leakage and edema formation in glioma through promoting vascular tightening. Moreover, when ABTAA was administered together with the chemotherapeutic drug temozolomide (TMZ), the tumor volume reduces further (76% by ABTAA+TMZ, 51% by ABA+TMZ, and 36% by TMZ). In the Lewis Lung Carcinoma (LLC) tumor model, the team administered ABTAA together with a chemotherapeutic drug called cisplatin (Cpt) and observed a greater suppression of tumor growth (52%) compared with the controls and increased overall survival. Moreover, ABTAA+Cpt led to a marked increase in necrotic area within tumors. Finally, in a spontaneous breast cancer model, ABTAA delayed tumor growth and enhanced the anti-tumor effect of Cpt. Courtesy of the Institute for Basic Sciences (IBS) Figure: The antibody ABTAA alone and in combination with other anti-cancer drugs have a beneficial effect in reducing tumor volume. ABTAA was tested in mice with brain tumor (glioma), lung or breast cancer. The image shows the improvements: reduction in glioma tumor size, reduction in metastatic colonies in lung tumor and decrease in necrotic regions in breast tumor. In the future, the team would like to further understand the underlying relationship between faulty blood vessels and diseases. “We would like to apply this antibody to an organ that is rich in blood vessels, that is the eye, and see if this antibody can be useful to treat eye diseases such as age-related macular degeneration and diabetic retinopathy,” concludes Koh. Professor Gou-Young Koh (left) and Jin-Sung Park (right)
2016.12.16
View 7521
Making Graphene Using Laser-induced Phase Separation
IBS & KAIST researchers clarify how laser annealing technology can lead to the production of ultrathin nanomaterials All our smart phones have shiny flat AMOLED (active-matrix organic light-emitting diode) displays. Behind each single pixel of these displays hides at least two silicon transistors which are mass-manufactured using laser annealing technology. While the traditional methods to make the transistors use temperature above 1,000°C, the laser technique reaches the same results at low temperatures even on plastic substrates (melting temperature below 300°C). Interestingly, a similar procedure can be used to generate crystals of graphene. Graphene is a strong and thin nano-material made of carbon, its electric and heat-conductive properties have attracted the attention of scientists worldwide. Professor Keon Jae Lee of the Materials Science and Engineering Department at KAIST and his research group at the Center for Multidimensional Carbon Materials within the Institute for Basic Science (IBS), as well as Professor Sung-Yool Choi of the Electrical Engineering School at KAIST and his research team discovered graphene synthesis mechanism using laser-induced solid-state phase separation of single-crystal silicon carbide (SiC). This study, available in Nature Communications, clarifies how this laser technology can separate a complex compound (SiC) into its ultrathin elements of carbon and silicon. Although several fundamental studies presented the effect of excimer lasers in transforming elemental materials like silicon, the laser interaction with more complex compounds like SiC has rarely been studied due to the complexity of compound phase transition and ultra-short processing time. With high resolution microscope images and molecular dynamic simulations, scientists found that a single-pulse irradiation of xenon chloride excimer laser of 30 nanoseconds melts SiC, leading to the separation of a liquid SiC layer, a disordered carbon layer with graphitic domains (about 2.5 nm thick) on top surface and a polycrystalline silicon layer (about 5 nm) below carbon layer. Giving additional pulses causes the sublimation of the separated silicon, while the disordered carbon layer is transformed into a multilayer graphene. "This research shows that the laser material interaction technology can be a powerful tool for the next generation of two dimensional nanomaterials," said Professor Lee. Professor Choi added: "Using laser-induced phase separation of complex compounds, new types of two dimensional materials can be synthesized in the future." High-resolution transmission electron microscopy shows that after just one laser pulse of 30 nanoseconds, the silicon carbide (SiC) substrate is melted and separates into a carbon and a silicon layer. More pulses cause the carbon layer to organize into graphene and the silicon to leave as gas. Molecular dynamics simulates the graphene formation mechanism. The carbon layer on the top forms because the laser-induced liquid SiC (SiC (l)) is unstable. (Press Release by Courtesy of the Institute for Basic Science (IBS))
2016.12.01
View 8878
Key Interaction between the Circadian Clock and Cancer Identified
Professor Jae Kyoung Kim and his research team from the Department of Mathematical Sciences at KAIST found that the circadian clock drives changes in circadian rhythms of p53 which functions as a tumor suppressor. Using a differential equation, he applied a model-driven mathematical approach to learn the mechanism and role of p53. Kim’s mathematical modeling has been validated by experimental studies conducted by a research team at Virginia Polytechnic Institute and State University (Virginia Tech) in the United State, which is led by Professor Carla Finkielstein. As a result, the researchers revealed that there is an important link existed between the circadian clock and cancer. The findings of this research were published online in Proceedings of the National Academy of Sciences of the United States of the America (PNAS) on November 9, 2016. The circadian clock in our brain controls behavioral and physiological processes within a period of 24 hours, including making us fall asleep at a certain time by triggering the release of the sleep hormone melatonin in our brain, for example, around 9 pm. The clock is also involved in various physiological processes such as cell division, movement, and development. Disruptions caused by the mismatch of the circadian clock and real time due to chronic late night work, shiftwork, and other similar issues may lead to various diseases such as diabetes, cancer, and heart disease. In 2014, when Kim met with Finkielstein, her research team succeeded in observing the changes of p53 over a period of 24 hours, but could not understand how the circadian clock controls the 24-hour rhythm of p53. It was difficult to determine p53’s mechanism since its cell regulation system is far more complex than other cells To solve the problem, Kim set up a computer simulation using mathematical modeling and ran millions of simulations. Instead of the traditional method based on trial and error experiments, mathematical modeling allowed to save a great deal of time, cost, and manpower. During this process, Kim proved that the biorhythm of p53 and Period2, an important protein in the circadian clock, are closely related. Cells usually consist of a cell nucleus and cytoplasm. While p53 exists in both nucleus and cytoplasm, it becomes more stable and its degradation slows down when it is in the nucleus. Kim predicted that the Period2 protein, which plays a key role in the functioning of the circadian clock, could influence the nucleus entry of the p53 protein. Kim’s predictions based on mathematical modeling have been validated by the Virginia team, thereby revealing a strong connection between the circadian clock and cancer. Researchers said that this research will help explain the cause of different results from numerous anticancer drugs, which are used to normalize the level of p53, when they are administrated at different times and find the most effective dosing times for the drugs. They also believe that this study will play an important role in identifying the cause of increasing cancer rates in shift-workers whose circadian clocks are unstable and will contribute to the development of more effective treatments for cancer. Professor Kim said, “This is an exciting thing that my research can contribute to improving the healthy lives of nurses, police officers, firefighters, and the like, who work in shifts against their circadian rhythms. Taking these findings as an opportunity, I hope to see more active interchanges of ideas between biological sciences and mathematical science in Korea.” This research has been jointly conducted between KAIST and Virginia Tech and supported by the T. J. Park Science Fellowship of POSCO, the National Science Foundation of the United States, and the Young Researcher Program of the National Research Foundation of Korea. Picture 1. The complex interaction between tumor antigen p53 and Period2 (Per2) which plays a major role in the circadian clock as revealed by mathematical simulations and experiments Picture 2. A portion of the mathematical model used in the research Picture 3. Professor Jae Kyoung Kim (third from left) and the Virginia Tech Research Team
2016.11.17
View 6328
2016 KAIST EEWS Workshop
The Energy, Environment, Water and Sustainability (EEWS) Graduate School of KAIST hosted a workshop entitled “Progress and Perspectives of Energy Science and Technology” on October 20, 2016. The workshop took place at the Fusion Hall of the KAIST Institute on campus. About 400 experts in energy science and engineering participated in the event. Eight globally recognized scientists introduced the latest research trends in nanomaterials, energy theory, catalysts, and photocatalysts and led discussions on the current status and prospects of EEWS. Professors Yi Cui of Stanford University, an expert in nanomaterials, and William A. Goddard of California Institute of Technology presented their research experiments on materials design and recent results on the direction of theory under the topics of energy and environment. Dr. Miquel Salmeron, a former head of the Material Science Division of Lawrence Berkeley National Laboratory, and Professor Yuichi Ikuhara of Tokyo University introduced their analysis of catalysts and energy matters at an atomic scale. Professor Sukbok Chang of the Chemistry Department at KAIST, a deputy editor of ACS Catalysis and the head of the Center for Catalytic Hydrocarbon Functionalizations at the Institute of Basic Science, and Professor Yang-Kook Sun of Energy Engineering at Hanyang University, who is also a deputy editor of ACS Energy Letters, presented their latest research results on new catalytic reaction development and energy storage. The workshop consisted of three sections which addressed the design of energy and environment materials; analysis of energy and catalytic materials; and energy conversion and catalysts. The EEWS Graduate School was established in 2008 with the sponsorship of the Korean government’s World Class University (WCU) project to support science education in Korea. Professor J. Fraser Stoddart, the winner of the 2016 Nobel Prize in Chemistry, was previously worked at the KAIST EEWS Graduate School as a WCU visiting professor for two years, from 2011 to 2013. Professor Ali Coskun, who was a postdoctoral researcher in the laboratory of Professor Stoddart, now teaches and conducts research as a full-time professor at the graduate school. Dean Yousung Jung of the EEWS Graduate School said: “This workshop has provided us with a meaningful opportunity to engage in discussions on energy science and technology with world-class scholars from all around the world. It is also a good venue for our graduate school to share with them what we have been doing in research and education.”
2016.10.20
View 9141
Continuous Roll-Process Technology for Transferring and Packaging Flexible Large-Scale Integrated Circuits
A research team led by Professor Keon Jae Lee from KAIST and by Dr. Jae-Hyun Kim from the Korea Institute of Machinery and Materials (KIMM) has jointly developed a continuous roll-processing technology that transfers and packages flexible large-scale integrated circuits (LSI), the key element in constructing the computer’s brain such as CPU, on plastics to realize flexible electronics. Professor Lee previously demonstrated the silicon-based flexible LSIs using 0.18 CMOS (complementary metal-oxide semiconductor) process in 2013 (ACS Nano, “In Vivo Silicon-based Flexible Radio Frequency Integrated Circuits Monolithically Encapsulated with Biocompatible Liquid Crystal Polymers”) and presented the work in an invited talk of 2015 International Electron Device Meeting (IEDM), the world’s premier semiconductor forum. Highly productive roll-processing is considered a core technology for accelerating the commercialization of wearable computers using flexible LSI. However, realizing it has been a difficult challenge not only from the roll-based manufacturing perspective but also for creating roll-based packaging for the interconnection of flexible LSI with flexible displays, batteries, and other peripheral devices. To overcome these challenges, the research team started fabricating NAND flash memories on a silicon wafer using conventional semiconductor processes, and then removed a sacrificial wafer leaving a top hundreds-nanometer-thick circuit layer. Next, they simultaneously transferred and interconnected the ultrathin device on a flexible substrate through the continuous roll-packaging technology using anisotropic conductive film (ACF). The final silicon-based flexible NAND memory successfully demonstrated stable memory operations and interconnections even under severe bending conditions. This roll-based flexible LSI technology can be potentially utilized to produce flexible application processors (AP), high-density memories, and high-speed communication devices for mass manufacture. Professor Lee said, “Highly productive roll-process was successfully applied to flexible LSIs to continuously transfer and interconnect them onto plastics. For example, we have confirmed the reliable operation of our flexible NAND memory at the circuit level by programming and reading letters in ASCII codes. Out results may open up new opportunities to integrate silicon-based flexible LSIs on plastics with the ACF packing for roll-based manufacturing.” Dr. Kim added, “We employed the roll-to-plate ACF packaging, which showed outstanding bonding capability for continuous roll-based transfer and excellent flexibility of interconnecting core and peripheral devices. This can be a key process to the new era of flexible computers combining the already developed flexible displays and batteries.” The team’s results will be published on the front cover of Advanced Materials (August 31, 2016) in an article entitled “Simultaneous Roll Transfer and Interconnection of Silicon NAND Flash Memory.” (DOI: 10.1002/adma.201602339) YouTube Link: https://www.youtube.com/watch?v=8OJjAEm27sw Picture 1: This schematic image shows the flexible silicon NAND flash memory produced by the simultaneous roll-transfer and interconnection process. Picture 2: The flexible silicon NAND flash memory is attached to a 7 mm diameter glass rod.
2016.09.01
View 8997
KAIST Develops Transparent Oxide Thin-Film Transistors
With the advent of the Internet of Things (IoT) era, strong demand has grown for wearable and transparent displays that can be applied to various fields such as augmented reality (AR) and skin-like thin flexible devices. However, previous flexible transparent displays have posed real challenges to overcome, which are, among others, poor transparency and low electrical performance. To improve the transparency and performance, past research efforts have tried to use inorganic-based electronics, but the fundamental thermal instabilities of plastic substrates have hampered the high temperature process, an essential step necessary for the fabrication of high performance electronic devices. As a solution to this problem, a research team led by Professors Keon Jae Lee and Sang-Hee Ko Park of the Department of Materials Science and Engineering at the KAIST has developed ultrathin and transparent oxide thin-film transistors (TFT) for an active-matrix backplane of a flexible display by using the inorganic-based laser lift-off (ILLO) method. Professor Lee’s team previously demonstrated the ILLO technology for energy-harvesting (Advanced Materials, February 12, 2014) and flexible memory (Advanced Materials, September 8, 2014) devices. The research team fabricated a high-performance oxide TFT array on top of a sacrificial laser-reactive substrate. After laser irradiation from the backside of the substrate, only the oxide TFT arrays were separated from the sacrificial substrate as a result of reaction between laser and laser-reactive layer, and then subsequently transferred onto ultrathin plastics ( thickness). Finally, the transferred ultrathin-oxide driving circuit for the flexible display was attached conformally to the surface of human skin to demonstrate the possibility of the wearable application. The attached oxide TFTs showed high optical transparency of 83% and mobility of even under several cycles of severe bending tests. Professor Lee said, “By using our ILLO process, the technological barriers for high performance transparent flexible displays have been overcome at a relatively low cost by removing expensive polyimide substrates. Moreover, the high-quality oxide semiconductor can be easily transferred onto skin-like or any flexible substrate for wearable application.” These research results, entitled “Skin-Like Oxide Thin-Film Transistors for Transparent Displays,” (http://onlinelibrary.wiley.com/doi/10.1002/adfm.201601296/abstract) were the lead article published in the July 2016 online issue of Wiley’s Advanced Functional Materials. ### References [1] Advanced Materials, February 12, 2014, Highly-efficient, Flexible Piezoelectric PZT Thin Film Nanogenerator on Plastic Substrates (http://onlinelibrary.wiley.com/doi/10.1002/adma.201305659/abstract) [2] Advanced Materials, September 8, 2014, Flexible Crossbar-structured Resistive Memory Arrays on Plastic Substartes via Inorganic-based Laser Lift-off (http://onlinelibrary.wiley.com/doi/10.1002/adma.201402472/abstract) Picture 1: A Schamatic Image of Ultrathin, Flexible, and Transparent Oxide Thin-film Transistors This image shows ultrathin, flexible, and transparent oxide thin-film transistors produced via the ILLO process. Picture 2: Application of Uultrathin, Flexible, and Transparent Oxide Thin-film Transistors This picture shows ultrathin, flexible, and transparent oxide thin-film transistors attached to a jumper sleeve and human skin.
2016.08.01
View 10634
Professor Seyun Kim Identifies a Neuron Signal Controlling Molecule
A research team led by Professor Seyun Kim of the Department of Biological Sciences at KAIST has identified inositol pyrophosphates as the molecule that strongly controls neuron signaling via synaptotagmin. Professors Tae-Young Yoon of Yonsei University’s Y-IBS and Sung-Hyun Kim of Kyung Hee University’s Department of Biomedical Science also joined the team. The results were published in the Proceedings of the National Academy of Sciences of the United States of America (PNAS) on June 30, 2016. This interdisciplinary research project was conducted by six research teams from four different countries and covered a wide scope of academic fields, from neurobiology to super resolution optic imaging. Inositol pyrophosphates such as 5-diphosphoinositol pentakisphos-phate (5-IP7), which naturally occur in corns and beans, are essential metabolites in the body. In particular, inositol hexakisphosphate (IP6) has anti-cancer properties and is thought to have an important role in cell signaling. Inositol pentakisphosphate (IP7) differs from IP6 by having an additional phosphate group, which was first discovered 20 years ago. IP7 has recently been identified as playing a key role in diabetes and obesity. Psychopathy and neurodegenerative diseases are known to result from the disrupted balance of inositol pyrophosphates. However, the role and the mechanism of action of IP7 in brain neurons and nerve transmission remained unknown. Professor Kim’s team has worked on inositol pyrophosphates for several years and discovered that very small quantities of IP7 control cell-signaling transduction. Professor Yoon of Yonsei University identified IP7 as a much stronger inhibitor of neuron signaling compared to IP6. In particular, IP7 directly suppresses synaptotagmin, one of the key proteins in neuron signaling. Moreover, Professor Kim of Kyung Hee University observed IP7 inhibition in sea horse neurons. Together, the joint research team identified inositol pyrophosphates as the key switch metabolite of brain-signaling transduction. The researchers hope that future research on synaptotagmin and IP7 will reveal the mechanism of neuron-signal transduction and thus enable the treatment of neurological disorders. These research findings were the result of cooperation of various science and technology institutes: KAIST, Yonsei-IBS (Institute for Basic Science), Kyung Hee University, Sungkyunkwan University, KIST, University of Zurich in Switzerland, and Albert-Ludwigs-University Freiburg in Germany. Schematic Image of Controlling the Synaptic Exocytotic Pathway by 5-IP7 , Helping the Understanding of the Signaling Mechanisms of Inositol Pyrophosphates
2016.07.21
View 9500
KAIST Team Develops Technology to Enable Unzipping of the Graphene Plane
Professor Sang-Wook Kim’s research team of the Material Science and Engineering Department has developed a technique, which enables unzipping of the graphene plane without uncontrollable damage. The research findings were published online on the January 22 issue of Nature Communications. Graphene is a form of carbon in which its atoms form a honey-comb structure through chemical bonding. If this structure can be cut to a desired form, other carbon materials with nanostructure can be created. Many researchers have tried to obtain the accurate unzipping of graphene structures, but faced challenges doing so. To break a very strong bond between carbon atoms, an equivalently strong chemical reaction must be induced. But the chemical reaction not only cuts out the desirable borders, but also damages the surrounding ones. Conventional techniques, which cut out graphene at once, damaged the chemical properties of the graphene structure after unzipping. This is similar to wearing out paper while manipulating it. To solve this problem, the research team adopted “heteroatom doping.” The idea is similar to a sheet of paper being split following a groove drawn on the sheet. After making some regions of the structure unstable by doping other atoms such as nitrogen on a carbon plane, the regions are electrochemically stimulated to split the parts. Nitrogen or other atoms act as the groove on the grapheme plane. The researchers finely controlled the amount of unzipping graphene by adjusting the amount of heteroatom dopants, from which they were able to create a quality nano graphene without any damage in its 2-dimensional crystalline structure. Using this technique, the researchers were able to obtain a capacitor with state-of-the-art energy transfer speed. The nano graphene can be combined with polymer, metal, and semiconductor nano molecules to form carbon composites. Professor Kim said, “In order to commercialize this technique, heteroatom doping should be researched further. We plan to develop fabric-like carbon materials with excellent mechanical and electrical properties using this technique.” Picture 1: Unzipped Carbon Nano Tube Picture 2: Development of Nano Graphene from Carbon Nano Tube Using Heteroatom Dopants Korean descriptions translated into English: Unzipping Process of Graphene Carbon Nano Tube → Nano Graphen Heteroatom This process is similar to a paper being split in two from a tiny hole punched therein.
2016.03.22
View 7534
<<
첫번째페이지
<
이전 페이지
11
12
13
14
15
16
17
18
19
20
>
다음 페이지
>>
마지막 페이지 28