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Electron Heating in Weakly Ionized Collisional Plasmas
(from left: Professor Wonho Choe and Research Professor Sanghoo Park)
A KAIST research team successfully identified the underlying principles behind electron heating, which is one of the most important phenomena in plasmas. As the electric heating determines wide range of physical and chemical properties of plasmas, this outcome will allow relevant industries to extend and effectively customize a range of plasma characteristics for their specific needs.
Plasma, frequently called the fourth state of matter, can be mostly formed by artificially energizing gases in standard temperature (25°C) and pressure (1 atm) range. Among the many types of plasma, atmospheric-pressure plasmas have been gaining a great deal of attention due to their unique features and applicability in various scientific and industrial fields.
Because plasma characteristics strongly depends on gas pressure in the sub-atmospheric to atmospheric pressure range, characterizing the plasma at different pressures is a prerequisite for understanding the fundamental principles of plasmas and for their industrial applications.
In that sense, information on the spatio-temporal evolution in the electron density and temperature is very important because various physical and chemical reactions within a plasma arise from electrons. Hence, electron heating has been an interesting topic in the field of plasma.
Because collisions between free electrons and neutral gases are frequent under atmospheric-pressure conditions, there are physical limits to measuring the electron density and temperature in plasmas using conventional diagnostic tools, thus the principles behind free electron heating could not be experimentally revealed.
Moreover, lacking information on a key parameter of electron heating and its controlling methods is troublesome and limit improving the reactivity and applicability of such plasmas.
To address these issues, Professor Wonho Choe and his team from the Department of Nuclear and Quantum Engineering employed neutral bremsstrahlung-based electron diagnostics in order to accurately examine the electron density and temperature in target plasmas. In addition, a novel imaging diagnostics for two dimensional distribution of electron information was developed.
Using the diagnostic technique they developed, the team measured the nanosecond-resolved electron temperature in weakly ionized collisional plasmas, and they succeeded in revealing the spatiotemporal distribution and the fundamental principle involved in the electron heating process.
The team successfully revealed the fundamental principle of the electron heating process under atmospheric to sub-atmospheric pressure (0.25-1atm) conditions through conducting the experiment on the spatiotemporal evolution of electron temperature.
Their findings of the underlying research data on free electrons in weakly ionized collisional plasmas will contribute to enhancing the field of plasma science and their commercial applications.
Professor Choe said, “The results of this study provide a clear picture of electron heating in weakly ionized plasmas under conditions where collisions between free electrons and neutral particles are frequent. We hope this study will be informative and helpful in utilizing and commercializing atmospheric-pressure plasma sources in the near future.”
Articles related to this research, led by Research Professor Sanghoo Park, were published in Scientific Reports on May 14 and July 5.
Figure 1. Nanosecond-resolved visualization of the electron heating structure. Spatiotemporal evolution of 514.5-nm continuum radiation,Te, Ar I emission
Figure 2. Nanosecond-resolved visualization of electron heating. Spatiotemporal evolution of neutral bremsstrahlung at 514.5 nm
2018.09.10 View 6132 -
There Won't Be a Singularity: Professor Jerry Kaplan
(Professor Jerry Kaplan gave a lecture titled, Artificial Intelligence: Think Again at KAIST)
“People are so concerned about super intelligence, but the singularity will not happen,” said Professor Jerry Kaplan at Stanford University, an AI guru and Silicon Valley entrepreneur during a lecture at KAIST. He visited KAIST to give a lecture on Artificial Intelligence: Think Again on September 6.
Professor Kaplan said that some people argue that Korea’s AI research is behind the US and China but he doesn’t agree with that. “Korea is the most digitally connected one and has the world’s best engineers in the field. Korean companies are building products the consumers really like at reasonable prices. Those are attracting global consumers,” he added.
Instead of investing loads of money on AI research, he suggested three tasks for Korea taking a better position in the field of AI: Collecting and saving lots of data; training engineers, not the research talents in AI; and investing in AI infrastructure and relieving regulations by the government.
Referring to AI hype, Professor Kaplan argued that machines are intelligent, but they do not think in the way humans can, and assured the audience that the singularity some futurists predict will not be coming. He said, “Machine learning is a tool extracting useful information, but it does not mean they are so smart that they are taking over the world.”
(Professor Jerry Kaplan gave a lecture titled, Artificial Intelligence: Think Again at KAIST)
But what has made us believing AI myths? He first began pointing out how AI has been mythicized by three major drivers. Those are the entertainment industry, the popular media, and the AI community all wanting to attract more public attention and prestige. The abovementioned drivers are falsely making robots more human and are adding human characteristics.
Instead of being captivated by those AI myths and thinking about how to save the world from robots, he strongly argued, “We need to develop standards for the unintended side effects from AI.” To provide machines socially and ethically mingling with the human world, he believed principles should be set as follows: Define the Safe Operating Envelope (SOE), “safe modes” when out of bounds, study human behavior programmatically, certification and licensing standards, limitations on machine “agency,” and basic computational ethics such as when it is okay to break the law.
Professor Kaplan gave a positive view of AI for humans. “The future will be bright, thanks to AI. They do difficult work and help us and that will drive wealth and quality of life. The rich might get richer, but the benefits will spread throughout the people. It is time to think of innovative ways for using AI for building better world,” he concluded.
2018.09.10 View 4822 -
NEREC Summer Program Keeps Fellows Thinking, Engaged in Nuclear Nonproliferation
Nuclear technology is more than just technology. It is the fruit of the most advanced science and technology. It also requires high standards of policymaking and global cooperation for benefiting the technology.
As part of the fifth annual Nuclear Nonproliferation Education and Research Center (NEREC) Summer Fellows Program at KAIST, 24 students from 15 countries participated in six-week intensive education and training program. NEREC is the only university-based center dedicated to nuclear nonproliferation education and research established in 2014.
The program, which provides multidisciplinary lectures and seminars on nuclear technology and policy as well as international relations, was designed to nurture global nuclear technology experts well equipped in three areas: in-depth knowledge of technology, applicability gained from sound policy building, and negotiating for international cooperation. It now has grown into the most popular summer program at KAIST.
During the program from July 6 to August 18, participants were able to engage in enriching and stimulating learning experiences in tandem with policies and technology for the utilization and provision of peaceful and safe nuclear technology.
Participating fellows also had to conduct a group research project on a given topic. This year, they explored nuclear nonproliferation issues in relation to nuclear exports and brainstormed some recommendations for current policy. They presented their outcomes at the 2018 NEREC Conference on Nuclear Nonproliferation. After intensive lecture sessions and group research work, the fellows went off to key policy think-tanks, nuclear research institutes, and research power facilities in Korea, Japan, and China.
“NEREC emphasizes nuclear nonproliferation issues related to civilian nuclear power and the associated nuclear fuel cycle development from the point of technology users. I am very glad that the number of participants are increasing year by year,” said the Director of NEREC Man-Sung Yim, a professor in the Department of Nuclear and Quantum Engineering.
Participants’ majors vary from nuclear engineering to international relations to economics. The fellows divided into two groups of graduate and undergraduate courses. They expressed their deep satisfactory in the multidisciplinary lectures by scholars from KAIST, Seoul National University, and Korea National Defense University.
Many participants reported that they learned a lot, not only about policy and international relations but on the research they are conducting and what the key issues will be in dealing for producing meaningful research work.
Moad Aldbissi from the KTH Royal Institute of Technology is one of the students who shared the same view. He said, “Coming from a technical background in nuclear engineering, I managed to learn a lot about nuclear policy and international relations. The importance of integrating the technical and political fields became even clearer.”
Most students concurred that they recognized how important it was to make international collaboration in this powerful field for each country through this program.
“As an engineering student, I just approached this program like an empty glass in policy areas. While working with colleagues during the program, I came to understand how important it is to make cooperation in these fields for the better result of national development and international relations,” said Thanataon Pornphatdetaudom from the Tokyo Institute of Technology.
To Director Yim, this program is becoming well positioned to educate nuclear policy experts in a number of countries of strategic importance. He believes the continuous supply of these experts will contribute to promoting global nuclear nonproliferation and the peaceful use of nuclear energy while the use of nuclear technology continues.
2018.09.04 View 8924 -
Adding Smart to Science Museum
KAIST and the National Science Museum (NSM) created an Exhibition Research Center for Smart Science to launch exhibitions that integrate emerging technologies in the Fourth Industrial Revolution, including augmented reality (AR), virtual reality (VR), Internet of Things (IoTs), and artificial intelligence (AI).
There has been a great demand for a novel technology for better, user-oriented exhibition services. The NSM continuously faces the problem of not having enough professional guides. Additionally, there have been constant complaints about its current mobile application for exhibitions not being very effective.
To tackle these problems, the new center was founded, involving 11 institutes and universities. Sponsored by the National Research Foundation, it will oversee 15 projects in three areas: exhibition-based technology, exhibition operational technology, and exhibition content.
The group first aims to provide a location-based exhibition guide system service, which allows it to incorporate various technological services, such as AR/VR to visitors. An indoor locating system named KAILOS, which was developed by KAIST, will be applied to this service. They will also launch a mobile application service that provides audio-based exhibition guides.
To further cater to visitors’ needs, the group plans to apply a user-centered ecosystem, a living lab concept to create pleasant environment for visitors.
“Every year, hundred thousands of young people visit the National Science Museum. I believe that the exhibition guide system has to be innovative, using cutting-edge IT technology in order to help them cherish their dreams and inspirations through science,” Jeong Heoi Bae, President of Exhibition and Research Bureau of NSM, emphasized.
Professor Dong Soo Han from the School of Computing, who took the position of research head of the group, said, “We will systematically develop exhibition technology and contents for the science museum to create a platform for smart science museums. It will be the first time to provide an exhibition guide system that integrates AR/VR with an indoor location system.”
The center will first apply the new system to the NSM and then expand it to 167 science museums and other regional museums.
2018.09.04 View 7331 -
Potential Drug to Cure Ciliopathies
(from left: Professor Joon Kim and PhD candidate Yong Joon Kim)
Ciliopathies are rare disorders involving functional and structural abnormalities of cilia. Although they are rare, they may reach 1 in 1,000 births. Unfortunately, there are no small-molecule drugs for treating ciliary defects. A KAIST research team conducted successful research that introduces a potential treatment that will be a foundation for developing drugs to treat the disease as well as a platform for developing small-molecule drugs for similar genetic disorders.
It was found that mutations in genes required for the formation or function of primary cilia cause ciliopathies and they result in cerebellar disorders, kidney dysfunction, and retinal degeneration.
Primary cilia are cell organelles playing a crucial role in the human body. They participate in intercellular signal transduction during embryonic development and allow retinal photoreceptor cells to function.
Currently, there are no approved drugs available for treating most ciliopathies. In fact, this is the case for most of the rare genetic disorders involving functional abnormalities through genetic mutation, and gene therapy is usually the only treatment available.
To tackle this issue, a team led by Professor Joon Kim from the Graduate School of Medical Science and Engineering and Ho Jeong Kwon from Yonsei University constructed a cell that mimics a gene-mutated CEP290, one of the main causes of ciliopathies, through genome editing. They then used cell-based compound library screening to obtain a natural small-molecule compound capable of relieving defects in ciliogenesis, the production of cilia.
The CEP290 protein forms a complex with a ciliopathy protein called NPHP5 to support the function of the ciliary transition zone. In cases where the CEP290 protein is not formed due to a genetic mutation, NPHP5 will not function normally. Here, the compound was confirmed to partially restore the function of the complex by normalizing the function of NPHP5.
The team also identified that the compound is capable of retarding retinal degeneration by injecting the compound into animal models.
As a result, they discovered a lead compound for developing medication to treat ciliopathy patients involving retinal degeneration. Hence, the findings imply that chemical compounds that target other proteins interacting with the disease protein can mitigate shortages of a disease protein in recessive genetic disorders.
PhD candidate Yong Joon Kim stated, “This study shows how genetic disorders caused by genetic mutation can be treated with small-molecule drugs.”
Professor Kim said, “Since the efficacy of the candidate drug has been verified through animal testing, a follow-up study will also be conducted to demonstrate the effect on humans.”
This research was published in the Journal of Clinical Investigation on July 23.
Figure 1. Identification of compounds that rescue ciliogenesis defects caused by CEP290 knockout
Figure 2. Eupatilin injection ameliorates M-opsin trafficking and electrophysiological response of cone photoreceptors in rd16 mice
2018.08.30 View 7391 -
Metabolic Engineering of E. coli for the Secretory Production of Free Haem
Researchers of KAIST have defined a novel strategy for the secretory production of free haem using engineered Escherichia coli (E. coli) strains. They utilized the C5 pathway, the optimized downstream pathways, and the haem exporter to construct a recombinant micro-organism producing extracellular haem using fed-batch fermentation. This is the first report to extracellularly produce haem using engineered E. coli.
This strategy will expedite the efficient production of free haem to serve as a bioavailable iron-supplying agent and an important prosthetic group of multiple hemoproteins for medical uses. This study, led by Distinguished Professor Sang Yup Lee of the Department of Chemical and Biomolecular Engineering, was published in Nature Catalysis on Aug. 28.
Haem, an organometallic compound complexed with a ferrous ion, is an essential molecule delivering oxygen in the blood of many animals. It is also a key component of electron transport chains responsible for the respiration of aerobic organisms including diverse bacteria. It is now being widely applied as a bioavailable iron-supplying agent in the healthcare and dietary supplement industries. The demand for haem and the need for the efficient production of this compound continue to grow.
Many previous researchers have attempted to produce free haem using engineered E. coli. However, none of the studies was successful in producing free haem extracellularly, requiring an additional step to extract the accumulated haem from cells for subsequent uses. The secretion of haem in the form of haem peptides or proteins also requires an extraction step to isolate the free haem from the secreted products. Thus, the secretory production of free haem is an important task for the economical production of haem that is suitable for human consumption.
Although some researchers could produce intracellular haem using recombinant E. coli strains, its final titer was extremely low, resulting from the use of sub-optimal metabolic pathways. Furthermore, the addition of the precursors L-glycine and succinate was deemed undesirable for massive industrial production. Thus, it is necessary to construct an optimized haem biosynthetic pathway to enable the efficient production of haem and examine the consequent secretion of free haem.
To address this issue, the KAIST team used multiple strategies to produce extracellular free haem by enhancing its biosynthesis in E. coli. First, the capacities of the C4 and C5 pathways to produce aminolevulinate (ALA) without feeding precursors were examined. After confirming the superior performance of the C5 pathway over the C4 pathway, the metabolic genes of the C5 pathway and downstream pathways for haem biosynthesis were overexpressed. Then, the metabolic pathways were optimized by adjusting the expression levels of the relevant genes and disrupting the putative haem degradation enzyme encoded by the yfeX gene.
Consequently, the resulting engineered strain secreted a significant amount of haem to the medium. Subsequent optimization of the cultivation conditions and the supplementation of nitrogen sources further increased both the titer of the total free haem and the amount of free haem secreted to the medium. Finally, the overexpression of the ccmABC genes encoding the haem exporter further enhanced the production and secretion of haem, producing the highest titer of haem both intracellularly and extracellularly from glucose.
Professor Lee said, “The eco-friendly and sustainable chemical industry is a key global agenda every nation faces. We are conducting research to bio-synthesize high concentrations, high yields, and high productivity in natural products. This novel technology will serve as an opportunity to advance the biochemical industry moving forward.”
This work was supported by the Technology Development Program to Solve Climate Changes on Systems Metabolic Engineering for Biorefineries (NRF-2012M1A2A2026556 and NRF-2012M1A2A2026557) from the Ministry of Science and ICT through the National Research Foundation (NRF) of Korea. Further Contact: Dr. Sang Yup Lee, Distinguished Professor, KAIST, Daejeon, Korea ( leesy@kaist.ac.kr+82-42-350-3930).
2018.08.28 View 5339 -
'K-FLEX' Makes a Splash as a Flexible Endoscopic Surgical Robot
( Robot arms perform an incision during an ex-vivo test on a porcine gallbladder.)
K-FLEX, a flexible endoscopic surgical robot developed by the KAIST Future Medical Robotics Research Center, opens a new chapter for minimally invasive robot-assisted surgery with its precision control of 3.7 mm diameter robotic arms. The two arms, placing at the end of flexible endoscopes, highlight impeccable precision control and robust mini-joint design technologies. While cruising through the complicated inner body pliably, it carries out procedures on the spot with its robotic arms.
The research team under Professor Dong-Soo Kwon recently tested the device in-vivo, conducting a complicated endoscopic procedure dissecting a porcine gallbladder in collaboration with Professor Dae-Kyung Son of the National Cancer Center. The arms successfully manipulated the tissue safely.
During the test, K-FLEX, inserted through an incision in the navel, snaked through the narrow passages of the complicated inner organs. When reaching the desired spot, one of the robot arms pushed aside and held up the nearby tissue to secure proper vision and space for the procedure. Meanwhile, a cautery needle mounted at the tip of the other hand removed the lesion tissue on the gallbladder. The tiny camera installed at the front of the robot arms relayed the internal conditions. The full procedure was able to be monitored from the master console.
The two arms are placed onto 4.2 mm internal channels of an endoscope which is 17 mm in diameter. The arms can be deployable forward and backward and are extendable up to 7 cm for performing procedures.
K-FLEX is made of domestically produced components, except for the endoscopic module. It will expand new medical robotics research while offering novel therapeutic capabilities for endoscopes.
Flexible endoscopes are very promising for surgical applications because they can treat areas thought to be difficult to reach, such as the posterior side of an organ. Current rigid-type laparoscopic tools could not reach a lesion if it occurs in such serpentine and complicated areas. However, this flexible endoscopic surgery robot will bypass obstacles to reach the troubled area.
The ability to seamlessly integrate effective actuation into millimeter-scale deployable mechanisms fits well with minimally invasive surgical procedures. This flexible endoscopic surgery robot, only half the size of current laparoscopic surgical robots, is deployable into natural orifices such as the mouth, anus, and vagina without requiring external incisions. Laparoscopic devices and robots require at least three to four external incisions to insert the devices; however, the applicability of internal incisions reduces the possibility of complications arousing from excessive bleeding and bacterial infections.
Despite these advantages, it has remained challenging to manipulate the robotic arms of flexible endoscopes with integrated grabbing force, flexibility, and multiple degrees of freedom for clinical environments.
The team focused on smaller but smarter devices. Dr. Min-Ho Hwang, a principal researcher of K-FLEX, said that developing tiny robots that are able to generate the necessary forces without compromising safety was the challenge. They created a robust but smaller-joint technology that can exert a relatively greater force even into millimeter scale.
Professor Kwon said, “K-FLEX is the first flexible endoscopic surgery robot in Korea. We already confirmed the clinical adaptation through ex vivo tests and will see complete commercialization in two to three years.” The team believes K-FLEX will be very effective for surgery on incipient cancer cells in the stomach, colon, and thyroid.
Professor Kwon and his eight researchers recently established a tech start-up called EasyEndo Surgical Inc. with these core technologies. In June, K-FLEX won the ‘Best Application Award’ and the ‘Overall Winner’ at the Surgical Robot Challenge 2018 held at Imperial College London. The Korea Research Foundation funded the research on K-FLEX.
(The team conducts a procedure using K-FLEX, flexible endoscopic surgical robot.)
2018.08.17 View 7848 -
The MSE/CBE Int'l Workshop Explores Big Ideas in Emerging Materials
(KAIST President Sung-Chul Shin with scholars participated in the workshop)
The MSE/CBE International Workshop brought together editors from key academic journals in multidisciplinary materials science and scholars from leading universities at KAIST on Aug. 7.
The workshop hosted ten distinguished speakers in the fields of nanostructures for next-generation emerging applications, chemical and bio-engineering, and materials innovation for functional applications. They explored opportunities and challenges for reinventing novel materials that will solve complex problems.
(From left: Professor Buriak, Professor Swager and Professor Il-Doo Kim)
Speakers included: Chief Editor of Nature Materials Vincent Dusastre; Editor-in- Chief of ACS NANO and professor at UCLA Paul S. Weiss; Jillian M. Buriak, Editor-in-Chief of Chemistry of Materials; Associate Editor of Macromolecules and professor at MIT Timothy M. Swager; Coordinating Editor of Acta Materialia and Head of the Department of Materials Science and Engineering at MIT Christopher A. Schuh; Editor-in-Chief of Biotechnology Journal and Metabolic Engineering and Distinguished Professor at KAIST Sang-Yup Lee; Associate Editor of Energy Storage Materials and professor at KAIST Sang Ouk Kim; Professor Jeffrey C. Grossman at MIT; Professor Zhenan Bao at Stanford University; and Professor Hyuck Mo Lee, head of the Department of Materials Science and Engineering at KAIST.
Interdisciplinary materials research holds the key to building technological competitiveness in many industrial sectors extending from energy, environment, and health care to medicine and beyond. It has also been the bedrock of KAIST’s scholarship and research innovation. More than 200 faculty members in the field of materials science produce about 800 SCI papers every year. The two departments of materials science and chemical biomolecular engineering are leading KAIST’s global reputation, as they were both ranked 13th and 14th in the QS World University Ranking by Subject this year.
(Professor Il-Doo Kim fromt he Department of Materials Science Engineering)
Professor Il-Doo Kim from the Department of Materials Science Engineering has been the chair of this workshop from 2016. In hosting the second one this year, he said that he hopes this year’s workshop will inspire many materials scientists to have big ideas and work to make those big ideas get noticed in order to have a real impact.
(KAIST President Sung-Chul Shin)
President Sung-Chul Shin, who is a physicist specializing in materials physics, expressed his keen interest in the workshop, saying innovative materials made of unthinkable and noble combinations will be the key factor in determining the competitiveness of new technology and new industries. He lauded international collaborations for making new materials and the scholarly passion to evaluate the materials’ characteristics that made this significant progress possible.
Dr. Vincent Dusastre, chief editor of Nature Materials, presented recent trends in materials for energy. He described how the rational design and improvement of materials’ properties can lead to energy alternatives which will compete with existing technologies. He pointed out that given the dramatic fundamental and practical breakthroughs that are taking place in the realization of solar cells with high energy-conversion efficiency, the improvement of batteries for electric vehicles and the grid is also a major challenge. He stressed, “Key advances in sustainable approaches beyond Li-ion batteries and control of redox processes are also greatly needed.”
Meanwhile, ACS NANO Editor-in-Chief Paul S. Weiss spoke on the importance of heterogeneity in the structure and function of molecules and nanoscale assemblies. He stressed that such extensiveness of multi-interdisciplinary research will accelerate a greater impact as indicated when the fields of neuroscience and microbiome converged with nanoscience and nanotechnology.
Editor-in-Chief of Chemistry of Materials Professor Jillian M. Buriak from the University of Alberta described how predictive models and machine learning can replace time consuming empirical device production and screening. By understanding and pinpointing the frustrating bottlenecks in the design of stable and efficient organic photovoltaics, much faster throughput can be obtained to enable a more direct pathway to stability, efficiency, and finally commercialization.
2018.08.13 View 11002 -
A Breakthrough for Understanding Glioblastoma: Origin Cells for Deadly Brain Tumors Identified
Figure 1. The pattern of GBM genesis is similar to that of firework. The bottom canon represents the first occurrence of the SVZ mutated cell.
A new study by KAIST researchers identified where the mutation causing glioblastoma starts. According to the study, neural stem cells away from the tumor mass are the cells of origin that contain mutation drivers for glioblastoma, one of the most aggressive brain tumor. This breakthrough research, reported in Nature on August 1, gives insights for understanding why glioblastomas almost always grow back, even after surgery, and suggests novel ways to treat glioblastoma, which was previously thought to be incurable.
Like most cancers, glioblastoma is treated with surgery to remove as much of the tumor as possible, then radiation and chemotherapy. However, it almost always returns in less than a year and its median survival time is only 15 months. Precision therapeutic approaches targeting tumors themselves didn’t lead to any breakthroughs.
Professor Jeong Ho Lee’s team at the Graduate School of Medical Science and Engineering described direct genetic evidence through the deep sequencing of all triple-matched samples: normal SVZ tissue away from the tumor mass, tumor tissue, and normal cortical tissue. The research team studied 28 patients with glioblastomas and other types of brain tumors who underwent supra-total resection or other surgical resections of tumors, providing access to normal subventricular zone (SVZ) tissue (where neural stem cells are located) away from the tumor mass. The researchers used various deep and single cell sequencing technologies to conduct comparative DNA analysis on the samples from the patient’s SVZ tissue and tumors.
They reported that normal SVZ tissue away from the tumor in 56.3% of patients with glioblastoma already contained low-level glioblastoma driver mutations that were observed at high levels in their matching tumors. Furthermore, the research team generated a genome edited mouse carrying glioblastoma mutations in the SVZ and showed that neural stem cells with mutations migrate from the SVZ lead to the development of glioblastomas in distant brain regions. (See the image below)
Professor Lee conducted this study in collaboration with Professor Seok-Gu Kang of the Brain Tumor Center at Severance Hospital of Yonsei University. He said, “It’s easier to understand when we compare it to fireworks. Every flare flying around sky can be likened to cancer cells even though the fireworks are triggered on the ground. We found the trigger.” The identification of this mutation pathway of glioblastomas will lead to a new paradigm for therapeutic strategies. He added, “Now, we can focus on interrupting the recurrence and evolution of glioblastomas.”
Professor Lee has investigated mutations arising in the brain for a decade. He is developing innovative diagnostics and therapeutics for untreatable brain disorders including intractable epilepsy and glioblastoma at a tech-startup, SoVarGen. “All technologies we used during the research were transferred to the company. This research gave us very good momentum to reach the next phase of our startup,” he remarked.
Figure 2. Genetic analysis of tumor-free SVZ tissue and matching tumor tissue from GBM patients.
Figure 3. Glioma progression in genome edited mice carrying GBM mutations in the SVZ
2018.08.02 View 11539 -
Participation in the 2018 Bio-Digital City Workshop in Paris
(A student make a presentatiion during the Bio-Digital City Workshop in Paris last month.)
KAIST students explored ideas for developing future cities during the 2018 Bio-Digital City Workshop held in Paris last month.
This international workshop hosted by Cité des Sciences et de l'Industrie was held under the theme “Biomimicry, Digital City and Big Data.” During the workshop from July 10 to July 20, students teamed up with French counterparts to develop innovative urban design ideas. Cité des Sciences et de l'Industrie is the largest science museum in Europe and is operated by Universcience, a specialized institute of science and technology in France.
Professor Seongju Chang from the Department of Civil and Environmental Engineering and Professor Jihyun Lee of the Graduate School of Culture Technology Students led the students group.
Participants presented their ideas and findings on new urban solutions that combine biomimetic systems and digital technology. Each student group analyzed a special natural ecosystem such as sand dunes, jellyfish communities, or mangrove forests and conducted research to extract algorithms for constructing sustainable urban building complexes based on the results. The extracted algorithm was used to conceive a sustainable building complex forming a part of the urban environment by applying it to the actual Parisian city segment given as the virtual site for the workshop.
Students from diverse background in both countries participated in this convergence workshop. KAIST students included Ph.D. candidate Hyung Min Cho, undergraduates Min-Woo Jeong, Seung-Hwan Cha, and Sang-Jun Park from the Department of Civil and Environmental Engineering, undergraduate Kyeong-Keun Seo from the Department of Materials Science and Engineering, JiWhan Jeong (Master’s course) from the Department of Industrial and Systems Engineering, Ph.D. candidate Bo-Yoon Zang from the Graduate School of Culture Technology. They teamed up with French students from diverse backgrounds, including Design/Science, Visual Design, Geography, Computer Science and Humanities and Social Science.
This workshop will serve as another opportunity to expand academic and human exchange efforts in the domain of smart and sustainable cities with Europe in the future as the first international cooperation activity of KAIST and the Paris La Villette Science Museum.
Professor Seong-Ju Chang who led the research group said, "We will continue to establish a cooperative relationship between KAIST and the European scientific community. This workshop is a good opportunity to demonstrate the competence of KAIST students and their scientific and technological excellence on the international stage.”
2018.08.01 View 9083 -
Visualizing Chemical Reaction on Bimetal Surfaces
Catalysts are the result of many chemists searching to unravel the beauty of molecules and the mystery of chemical reactions. Professor Jeong Young Park from the Department of Chemistry, whose research focuses on catalytic chemical reactions, is no exception. His research team recently made breakthroughs in addressing long-standing questions for understanding reaction mechanisms on bimetal catalysts.
During the studies reported in Science Advances, following a publication in Nature Communications this month, Professor Park’s research team identified that the formation of metal–oxide interfaces is the key factor responsible for the synergistic catalytic effect in bimetal catalysts. The team confirmed this fundamental reaction mechanism through in situ imaging of reaction conditions. This is the first visualization of bimetal surfaces under reaction conditions, signifying the role of metal–oxide interfaces in heterogeneous catalysis.
Bimetallic materials have outstanding catalytic performance, which opens a new pathway for controlling electronic structures and binding energy in catalysts. Despite considerable research on various catalytic reaction efficiencies, there are yet unanswered questions on the underlying principles behind the improved performance. Even more, it was very hard to figure out what led to the efficiency because the structure, chemical composition, and oxidation state of bimetallic materials change according to reaction conditions.
Recently, some research groups suggested that oxide–metal interfacial sites formed by the surface segregation of bimetallic nanoparticles might be responsible for the increased catalytic performance. However, they failed to present any definitive evidence illustrating the physical nature or the fundamental role of the oxide–metal interfaces leading to the improved performance.
To specifically address this challenge, the research team carried out in situ observations of structural modulation on platinum–nickel bimetal catalysts under carbon monoxide oxidation conditions with ambient pressure scanning tunneling microscopy and ambient pressure X-ray photoelectron spectroscopy.
The team observed that platinum–nickel bimetal catalysts exhibited a variety of different structures depending on the gas conditions. Under ultrahigh vacuum conditions, the surface exhibited a platinum skin layer on the platinum–nickel alloyed surface, selective nickel segregation followed by the formation of nickel oxide clusters using oxygen gas, and finally the coexistence of nickel oxide clusters on the platinum skin during carbon monoxide oxidation. The research team found that the formation of interfacial platinum–nickel oxide nanostructures is responsible for a highly efficient step in the carbon monoxide oxidation reaction.
These findings illustrate that the enhancement of the catalytic activity on the bimetallic catalyst surface originates from the thermodynamically efficient reaction pathways at the metal–metal oxide interface, which demonstrates a straightforward process for the strong metal–support interaction effect. The formation of these interfacial metal–metal oxide nanostructures increases catalytic activity while providing a thermodynamically efficient reaction pathway by lowering the heat of the reactions on the surface. [J. Kim et al. Adsorbate-driven reactive interfacial Pt-NiO1-x nanostructure formation on the Pt3Ni(111) alloy surface, Science Advances (DOI: 10.1126/sciadv.aat3151 ]
Professor Park said that one way to monitor catalysts is to detect hot electrons associated with energy dissipation and conversion processes during surface reactions. His team led the real-time detection of hot electrons generated on bimetallic PtCo nanoparticles during exothermic hydrogen oxidation. The team successfully clarified the origin of the synergistic catalytic activity of PtCo nanoparticles with corresponding chemicurrent values.
By estimating the chemicurrent yield, the research team conclude that the catalytic properties of the bimetallic nanoparticles are strongly governed by the oxide–metal interface, which facilitates hot electron transfer. [H. Lee et al. Boosting hot electron flux and catalytic activity at metal–oxide interfaces of PtCo bimetallic nanoparticles, Nature Comm, 9, 2235 (2018)].
Professor Park explained, “We feel that the precise measurement of hot electrons on catalysts gives insight into the mechanism for heterogeneous catalysis, which can help with the smart design of highly reactive materials. The control of catalytic activity via electronic engineering of catalysts is a promising prospect that may open the door to the new field of combining catalysis with electronics, called “catalytronics.” He added that the study also establishes a strategy for improving catalytic activity for catalytic reactions in industrial chemical reactors.
Professors Park and Yousung Jung from the Department of Chemical and Biomolecular Engineering and the Graduate School of EEWS conducted this research in collaboration with Professor Bongjin Mun from the Department of Physics at GIST.
Figure 1. Evolution of surface structures of PtNi bimetal surfaces under various ambient conditions.
Figure 2. Formation of Pt-CoO interface leads to the catalytic enhancement of PtCo bimetal catalysts.
2018.07.25 View 8807 -
It's Time to 3D Sketch with Air Scaffolding
People often use their hands when describing an object, while pens are great tools for describing objects in detail. Taking this idea, a KAIST team introduced a new 3D sketching workflow, combining the strengths of hand and pen input. This technique will ease the way for ideation in three dimensions, leading to efficient product design in terms of time and cost.
For a designer's drawing to become a product in reality, one has to transform a designer's 2D drawing into a 3D shape; however, it is difficult to infer accurate 3D shapes that match the original intention from an inaccurate 2D drawing made by hand. When creating a 3D shape from a planar 2D drawing, unobtainable information is required. On the other hand, loss of depth information occurs when a 3D shape is expressed as a 2D drawing using perspective drawing techniques.
To fill in these “missing links” during the conversion, "3D sketching" techniques have been actively studied. Their main purpose is to help designers naturally provide missing 3D shape information in a 2D drawing. For example, if a designer draws two symmetric curves from a single point of view or draws the same curves from different points of view, the geometric clues that are left in this process are collected and mathematically interpreted to define the proper 3D curve. As a result, designers can use 3D sketching to directly draw a 3D shape as if using pen and paper.
Among 3D sketching tools, sketching with hand motions, in VR environments in particular, has drawn attention because it is easy and quick. But the biggest limitation is that they cannot articulate the design solely using rough hand motions, hence they are difficult to be applied to product designs. Moreover, users may feel tired after raising their hands in the air during the entire drawing process.
Using hand motions but to elaborate designs, Professor Seok-Hyung Bae and his team from the Department of Industrial Design integrated hand motions and pen-based sketching, allocating roles according to their strengths. This new technique is called Agile 3D Sketching with Air Scaffolding. Designers use their hand motions in the air to create rough 3D shapes which will be used as scaffolds, and then they can add details with pen-based 3D sketching on a tablet (Figure 1).
Figure 1. In the agile 3D sketching workflow with air scaffolding, the user (a) makes unconstrained hand movements in the air to quickly generate rough shapes to be used as scaffolds, (b) uses the scaffolds as references and draws finer details with them, (c) produces a high-fidelity 3D concept sketch of a steering wheel in an iterative and progressive manner.
The team came up with an algorithm to identify descriptive hand motions from transitory hand motions and extract only the intended shapes from unconstrained hand motions, based on air scaffolds from the identified motions.
Through user tests, the team identified that this technique is easy to learn and use, and demonstrates good applicability. Most importantly, the users can reduce time, yet enhance the accuracy of defining the proportion and scale of products.
Eventually, this tool will be able to be applied to various fields including the automobile industry, home appliances, animations and the movie making industry, and robotics. It also can be linked to smart production technology, such as 3D printing, to make manufacturing process faster and more flexible.
PhD candidate Yongkwan Kim, who led the research project, said, “I believe the system will enhance product quality and work efficiency because designers can express their 3D ideas quickly yet accurately without using complex 3D CAD modeling software. I will make it into a product that every designer wants to use in various fields.”
“There have been many attempts to encourage creative activities in various fields by using advanced computer technology. Based on in-depth understanding of designers, we will take the lead in innovating the design process by applying cutting-edge technology,” Professor Bae added.
Professor Bae and his team from the Department of Industrial Design has been delving into developing better 3D sketching tools. They started with a 3D curve sketching system for professional designers called ILoveSketch and moved on to SketchingWithHands for designing a handheld product with first-person hand postures captured by a hand-tracking sensor. They then took their project to the next level and introduced Agile 3D Sketching with Air Scaffolding, a new 3D sketching workflow combining hand motion and pen drawing which was chosen as one of the CHI (Conference on Human Factors in Computing Systems) 2018 Best Papers by the Association for Computing Machinery.
- Click the link to watch video clip of SketchingWithHands
2018.07.25 View 8810