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Hierarchically-Porous Polymers with Fast Absorption
KAIST's Professor Myungeun Seo and his research team from the Graduate School of Nanoscience and Technology has developed a method to form micropores of less than 2 nanometers within porous polymers where 10 nanometers long mesopores connect like a net. The advantage of the porous polymers is fast absorption of molecules.
Porous polymers with micropores of less than 2 nanometers, like a zeolite, have a large surface area. They are used as a means to store hydrogen-based molecules or as a catalytic support that can be used as a surface to convert a material into a desired form. However, because the size of the pores in its path was too small for the molecules, it took a long time to spread into the pores and reach the surface.
To reach the surface efficiently, a lung cell or the vein of a leaf has a structure wherein the pores are subdivided into different sizes so that the molecule can spread throughout the organ. A technology that can create not only micropores but also bigger pores was necessary in order to create such structure.
The research team solved the issue by implementing a "self-assembly" of block polymers to easily form a net-like nanostructure from mesopores of 10 nanometers.
The team created hierarchically-porous polymers consisting of two different types of pores by using a hypercrosslinking reaction along with the "self-assembly" method. The reaction creates micropores within the chain after the polymer chain is confined by a chemical bond.
This porous polymer has micropores that are smaller than 2 nanometers on the walls of mesopores while 10 nanometers long mesopores forming 3-dimensional net structures. Because of the "self-assembly" method, the size of mesopores can be adjusted within the range of 6 to 15 nanometers.
This is the first case where a porous polymer has both well-defined mesopores and micropores. The research team verified the effect of hierarchically-porous structures on absorption of molecules by confirming that the porous polymer had faster absorption speeds than a polymer consisting only of micropores.
Professor Seo said, “The study has found a simple way to create different sizes of pores within a polymer.” He expected that the hierarchically-porous polymers can be used as a catalytic support in which fast diffusion of molecules is essential, or for molecule collection.
The research was sponsored by National Research Foundation of Korea and published online in the Journal of the American Chemical Society.
Figure 1 – Net-like Structure of Hierarchically-Porous Polymers with Mesopores and Micropores on the walls of Mesopores.
Figure 2 - Hierarchically-Porous Polymers
Figure 3 – Comparison of Porous-Polymers consisting of Mesopores only (left), and Mesopores and Micropores (right)
2015.01.13 View 8074 -
Professor Eunjoon Kim Is KAIST's Person of the Year 2014
KAIST announced that it has named Chair Professor Eunjoon Kim of the Department of Biological Sciences as its “Person of the Year 2014.” The award ceremony took place at the auditorium on campus on January 5, 2014.
Established in 2001, the award has been presented to a KAIST faculty member who has made great achievements in research and education, thereby contributing to the advancement of KAIST.
Professor Kim was the first to identify the mechanism of synapse formation between neurons during his post-doctoral program at Harvard Medical School in 1995. The research was published in Nature.
In 2011, Professor Kim discovered that the lack of protein GIT1, a neuronal synapse in the brain, caused ADHD (Attention Deficit Hyperactivity Disorder). He is widely recognized for his work concerning synapse proteins and brain disease related research that set the foundation for future medical developments.
In his award speech, Professor Kim said, “Whenever a research finding concerning a new drug therapy or research is published, I receive many inquiries from the parents of children with ADHD or autism. As a scientist, I would like to focus my research ultimately to help those in pain, rather than just pursuing research excellence or reputation.”
2015.01.06 View 9748 -
A Key Signal Transduction Pathway Switch in Cardiomyocyte Identified
A KAIST research team has identified the fundamental principle in deciding the fate of cardiomyocyte or heart muscle cells. They have determined that it depends on the degree of stimulus in β-adrenergic receptor signal transduction pathway in the cardiomyocyte to control cells' survival or death. The findings, the team hopes, can be used to treat various heart diseases including heart failure.
The research was led by KAIST Department of Bio and Brain Engineering Chair Professor Kwang-Hyun Cho and conducted by Dr. Sung-Young Shin (lead author) and Ph.D. candidates Ho-Sung Lee and Joon-Hyuk Kang. The research was conducted jointly with GIST (Gwangju Institute of Science and Technology) Department of Biological Sciences Professor Do-Han Kim’s team. The research was supported by the Ministry of Science, ICT and Future Planning, Republic of Korea, and the National Research Foundation of Korea. The paper was published in Nature Communications on December 17, 2014 with the title, “The switching role of β-adrenergic receptor signalling in cell survival or death decision of cardiomyocytes.”
The β-adrenergic receptor signal transduction pathway can promote cell survival (mediated by β2 receptors), but also can result in cell death by inducing toxin (mediated by β1 receptors) that leads to various heart diseases including heart failure. Past attempts to identify the fundamental principle in the fate determining process of cardiomyocyte based on β-adrenergic receptor signalling concluded without much success.
The β-adrenergic receptor is a type of protein on the cell membrane of cardiomyocyte (heart muscle cell) that when stimulated by neurohormones such as epinephrine or norepinephrine would transduce signals making the cardiomyocyte contract faster and stronger.
The research team used large-scale computer simulation analysis and systems biology to identify ERK* and ICER** signal transduction pathways mediated by a feed-forward circuit as a key molecular switch that decides between cell survival and death.
Weak β-adrenergic receptor stimulations activate ERK signal transduction pathway, increasing Bcl-2*** protein expression to promote cardiomyocyte survival. On the other hand, strong β-adrenergic receptor stimulations activate ICER signal transduction pathway, reducing Bcl-2 protein expression to promote cardiomyocyte death.
Researchers used a systems biology approach to identify the mechanism of B-blocker****, a common drug prescribed for heart failure. When cardiomyocyte is treated with β1 inhibitor, strong stimulation on β-adrenergic receptor increases Bcl-2 expression, improving the chance of cardiomyocyte survival, a cell protection effect.
Professor Kwang-Hyun Cho said, “This research used systems biology, an integrated, convergence research of IT (information technology) and BT (biotechnology), to successfully identify the mechanism in deciding the fate of cardiomyocytes based on the β-adrenergic receptor signal transduction pathway for the first time. I am hopeful that this research will enable the control of cardiomyocyte survival and death to treat various heart diseases including heart failure.”
Professor Cho’s team was the first to pioneer a new field of systems biology, especially concerning the complex signal transduction network involved in diseases. Their research is focused on modelling, analyzing simulations, and experimentally proving signal pathways. Professor Cho has published 140 articles in international journals including Cell, Science, and Nature.
* ERK (Extracellular signal-regulated kinases): Signal transduction molecule involved in cell survival
** ICER (Inducible cAMP early repressor): Signal transduction molecule involved in cell death
*** Bcl-2 (B-cell lymphoma 2): Key signal transduction molecule involved in promotion of cell survival
**** β-blocker: Drug that acts as β-adrenergic receptor inhibitor known to slow the progression of heart failure, hence used most commonly in medicine.
Picture: A schematic diagram for the β-AR signalling network
2015.01.05 View 12270 -
Professor Mikyoung Lim Receives the MediaV Young Researcher Award
Professor Mikyoung Lim of the Department of Mathematical Sciences at KAIST received the MediaV Young Researchers Award at the International Conference on Inverse Problems and Related Topics that took place at the National Taiwan University, Taiwan, on December 15-19, 2014.
The Conference established the MediaV Young Researcher Award in 2010 to recognize distinguished scholars who are age 40 or younger and have made important contributions to the field of inverse problems. This year, two recipients were chosen for the award.
Professor Lim has focused her research on the incremental reading of incomprehensible materials’ imaging and the effect of invisibility cloaking.
The other awardee was Kui Ren, a professor at the University of Texas at Austin.
2014.12.27 View 9816 -
KAIST wins second place in unmanned boat competition
KAIST took second place in an international competition to promote technologies of the autonomous underwater vehicle (AUV).
Professor Jin-hwan Kim’s research team from KAIST’s Ocean Systems Engineering Department won the second place in Maritime RobotX Challenge which took place for the first time from October 20 - 26 in Marina Bay, Singapore.
Along with automobiles and drones, the necessity for unmanned boats has grown. To encourage and examine the development of these technologies, the U.S. Office of Naval Research decided to organize an unmanned boat competition which took place for the first time this year.
After three teams were selected from a domestic competition in each countries, a total of fifteen teams from five countries from the Pacific Rim including Korea, the United States, Australia, Japan, and Singapore competed. Teams from such universities as MIT, Tokyo University, Tokyo Institute of Technology, National University of Singapore, Nanyang Technological University, and Queensland University of Technology participated. In addition to KAIST, Seoul National University and Ulsan University participated.
Using a 4.5 meters long and 2.5 meters wide unmanned boat provided by the organizer, each team had to implement an integrated system that combined a propulsion system, hardware, and autonomous software. Each team’s vessel had to perform tasks without manual control, employing autonomous driving through recognition of the course, searching underwater for acoustic sources, automatically approaching piers, remote observation of buoy, and avoidance and detection of obstacles.
Although KAIST outpaced MIT in the semifinal which selected six out of fifteen teams, it won the second place in the final. As well as winning second prize, KAIST also won best website prize and a special prize from the competition sponsor, Northrop Grumman Corporation, an American defense technology company, totaling 16,500 U.S. dollars of prize money.
The Vice President for Planning and Budget, Professor Seungbin Park said, “It was a great opportunity to showcase the advanced unmanned robot technology of Korea.” He added that “this raised KAIST’s reputation as a global research oriented university.”
Professor Kim commented, “Along with automobiles and drones, the necessity for the development of unmanned ocean vehicles such as unmanned boats and submarines are recognized these days.” He added that “the use of unmanned boats will make the process of channel investigation, ocean exploration, surveillance over water territories safer and more effective.”
Professor Kim’s team was sponsored by the U.S. Office of Naval Research, Samsung Heavy Industries, Sonar Tech, Daeyang Electric, and Red-one Technology.
KAIST Team's Unmanned Boat
The Competition's Missions
2014.12.12 View 10331 -
KAIST Partners with Science-focused Universities in Korea for Student Exchange Programs
KAIST and four science-focused universities in Korea (Pohang University of Science and Technology, Gwangju Institute of Science and Technology, Daegu Gyeongbuk Institute of Science and Technology, and Ulsan National Institute of Science and Technology) agreed to exchange programs during academic semesters including summer and winter terms by signing a memorandum of understanding (MOU) on November 28, 2014. The signing ceremony took place at the KAIST campus with the participation of academic affairs deans from all five universities.
Based on the agreement, KAIST students can take up to 12 credits of coursework at any of the said universities and have unimpeded access to the university facilities during their coursework.
Dean Hyun-Wook Park of Academic Affairs at KASIT said, “Through exchange programs, students can capitalize on each university’s advantages, and this eventually will lead to greater advancement in science and technology in the nation.”
2014.12.08 View 7574 -
Nanoparticle Cluster Manufacturing Technique Using DNA Binding Protein Developed
Professor Hak-Sung Kim of the Department of Biological Sciences at KAIST and Yiseul Ryu, a doctoral candidate, used the Zinc Finger protein that specifically binds to target DNA sequence to develop a new manufacturing technique for size-controllable magnetic Nanoparticle Clusters (NPCs). Their research results were published in Angewandte Chemie International Edition online on 25 November 2014.
NPCs are structures consisting of magnetic nanoparticles, gold nanoparticles, and quantum dots, each of which are smaller than 100 nm (10-9m). NPCs have a distinctive property of collectivity not seen in single nanoparticles.
Specifically NPCS differ in physical and optical properties such as Plasmon coupling absorbance, energy transfers between particles, electron transfers, and conductivity. Therefore, NPCs can be employed in biological and medical research as well as the development of nanoelectric and nanoplasmon devices.
To make use of these novel properties, the size and the composition of the cluster must be exquisitely controlled. However, previous techniques relied on chemical binding which required complex steps, making it difficult to control the size and composition of NPCs.
Professor Kim’s team used Zinc Finger, a DNA binding protein, to develop a NPCs manufacturing technique to create clusters of the desired size easily. The Zinc Finger protein contains a zinc ion and specifically recognizes DNA sequence upon binding, which allows the exquisite control of the size and the cluster composition. The technique is also bio-friendly.
Professor Kim’s team created linear structure of different sizes of NPCs using Zinc Finger proteins and three DNA sequences of different lengths. The NPCs they produced confirmed their ability to control the size and structure of the cluster by using different DNA lengths.
The NPCs showed tripled T2 relaxation rates compared to the existing MRI contrast media (Feridex) and effectively transported to targeted cells. The research findings show the potential use of NPCs in biological and medical fields such as MRI contrast media, fluorescence imaging, and drug transport.
The research used the specific binding property of protein and DNA to develop a new method to create an inorganic nanoparticle’s supramolecular assembly. The technique can be used and applied extensively in other nanoparticles for future research in diagnosis, imaging, and drug and gene delivery.
Figure 1. A Mimetic Diagram of NPCs Manufacturing Technique Using DNA Binding Protein Zinc Finger
Figure 2. Transmission Electron Microscopy Images showing different sizes of NPCs depending on the length of the DNA
2014.12.04 View 11919 -
Broadband and Ultrathin Polarization Manipulators Developed
Professor Bumki Min from the Department of Mechanical Engineering at KAIST has developed a technology that can manipulate a polarized light in broadband operation with the use of a metamaterial.
It is expected that this technology will lead to the development of broadband optical devices that can be applied to broadband communication and display.
When an object or its structure is analyzed by using a polarized light such as a laser, the results are generally affected by the polarized state of the light. Therefore, in an optics laboratory, the light is polarized by various methods.
In such cases, researchers employ wave plates or photoactive materials. However, the performance of these devices depend vastly on wavelength, and so they are not suitable to be used as a polarizer, especially in broadband.
There were many attempts to make artificial materials that are very photoactive by using metamaterials which have a strong resonance. Nonetheless, because the materials had an unavoidable dispersion in the resonance frequency, they were not adequate for broadband operation.
Professor Min’s research team arranged and connected helical metamaterials that are smaller than the wavelength of light. They verified theoretically and experimentally that polarized light can be constantly rotated regardless of the wavelength by super-thin materials that have thickness less than one-tenth of the wavelength of the light. The experiment which confirmed the theory was conducted in the microwave band.
Broadband polarized rotational 3D metamaterials were found to rotate the polarized microwave within the range of 0.1 GHz to 40 GHz by 45 degrees regardless of its frequency. This nondispersive property is quite unnatural because it is difficult to find a material that does not change in a wide band.
In addition, the research team materialized the broadband nondispersive polarized rotational property by designing the metamaterial in a way that it has chirality, which determines the number of rotations proportional to the wavelength.
Professor Min said, “As the technology is able to manipulate ultrathin polarization of light in broadband, it will lead to the creation of ultra-shallow broadband optical devices.”
Sponsored by the Ministry of Science, ICT and Future Planning of the Republic of Korea and the National Research Foundation of Korea, this research was led by a PhD candidate, Hyun-Sung Park, under the guidance of Professor Min. The research findings were published online in the November 17th issue of Nature Communications.
Figure 1 – Broadband and Ultrathin Polarization Manipulators Produced by 3D Printer
Figure 2 – Concept of Broadband and Ultrathin Polarization Manipulators
2014.12.03 View 10493 -
Structure of Neuron-Connecting Synaptic Adhesion Molecules Discovered
A research team has found the three-dimensional structure of synaptic adhesion molecules, which orchestrate synaptogenesis. The research findings also propose the mechanism of synapses in its initial formation. Some brain diseases such as obsessive compulsive disorder (OCD) or bipolar disorders arise from a malfunction of synapses. The team expects the findings to be applied in investigating pathogenesis and developing medicines for such diseases.
The research was conducted by a Master’s candidate Kee Hun Kim, Professor Ji Won Um from Yonsei University, and Professor Beom Seok Park from Eulji University under the guidance of Professor Homin Kim from the Graduate School of Medical Science and Engineering, KAIST, and Professor Jaewon Ko from Yonsei University. Sponsored by the Ministry of Science, ICT and Future Planning and the National Research Foundation of Korea, the research findings were published online in the November 14th issue of Nature Communications.
A protein that exists in the neuronal transmembrane, Slitrk, interacts with the presynaptic leukocyte common antigen-related receptor protein tyrosine phosphatases (LAR-RPTPs) and forms a protein complex. It is involved in the development of synapses in the initial stage, and balances excitatory and inhibitory signals of neurons.
It is known that a disorder in those two proteins cause a malfunction of synapses, resulting in neuropsychosis such as autism, epilepsy, OCD, and bipolar disorders. However, because the structure as well as synaptogenic function of these proteins were not understood, the development of cures could not progress.
The research team discovered the three-dimensional structure of two synaptic adhesion molecules like Slitrk and LAR-RPTPs and identified the regions of interaction through protein crystallography and transmission electron microscopy (TEM). Furthermore, they found that the formation of the synapse is induced after the combination of two synaptic adhesion molecules develops a cluster.
Professor Kim said, “The research findings will serve as a basis of understanding the pathogenesis of brain diseases which arises from a malfunction of synaptic adhesion molecules. In particular, this is a good example in which collaboration between structural biology and neurobiology has led to a fruitful result.” Professor Ko commented that “this will give new directions to synaptic formation-related-researches by revealing the molecular mechanism of synaptic adhesion molecules.”
Figure 1: Overview of the PTPd Ig1–3/Slitrk1 LRR1 complex.
Figure 2: Representative negative-stained electron microscopy images of Slitrk1 Full ectodomain (yellow arrows indicate the horseshoe-shaped LRR domains). The typical horseshoe-shaped structures and the randomness of the relative positions of each LRR domain can be observed from the two-dimensional class averages displayed in the orange box.
Figure 3: Model of the two-step presynaptic differentiation process mediated by the biding of Slitrks to LAR-RPTPs and subsequent lateral assembly of trans-synaptic LAR-RPTPs/Slitrik complexes.
2014.11.28 View 10933 -
Elsevier Selects a KAIST Graduate's Paper as the Top Cited Papers in 2011-2012
Dr. Myung-Won Seo, a graduate from the Department of Chemical and Bimolecular Engineering at KAIST, published a paper in January 2011 in Chemical Engineering Journal, which was entitled “Solid Circulation and Loop-seal Characteristics of a Dual Circulating Fluidized Bed: Experiments and CFD Simulation.” His paper was selected by Elsevier as the Top Cited Papers of 2011-2012. The Chemical Engineering Journal is a renowned peer-reviewed journal issued by Elsevier.
Dr. Seo published another paper, “CFD Simulation with Experiments in a Dual Circulating Fluidized Bed Gasifier,” in January 2012 in Computers & Chemical Engineering, which was also selected as the Most Downloaded Papers in 2012-2013.
Dr. Seo graduated with a doctoral degree from KAIST in 2011. He is currently working at the Clean Fuel Laboratory, the Korea Institute of Energy Research, Daejeon, as a researcher. His research areas are coal gasification, upgrading, and liquefaction, as well as energy and chemical production from low-grade fuels such as biomass and wastes.
2014.11.24 View 8746 -
KAIST Robotic Art: Exhibit called "Artificial Brain, Robots Evolve"
It is not difficult to find the desire to create a Neoanthropinae in the history of mankind. Humans evolve through man-made extensions and live by self-training them. This is Seung Hyun Son’s description which encourages us to discuss the changes man-made humanoids would bring to our future lives. He depicts this in “Theory of Evolution: From mankind to humanoid” in the “Artificial Brain, Robots Evolve” exhibition in the KI Building, KAIST, from 21 November 2014 to 8 February 2015.
KAIST's Art and Design Committee (led by President Myung Seok Kim) is holding the third experimental art exhibition based on the integration of science and art. The previous exhibition themes were “See the Sky” in 2012 and “Life is Beautiful” in 2013. The exhibition is divided into five subtopics: Move, Feel, Think, Express, and Experiment in Imagination.
The exhibits are by 17 artists including Nam June Paik, Nancy Lang, and KAIST Professor Myung Seok Kim. The main exhibits include “Cloud Face,” by Seung Baek Shin and Yong Hoon Kim, that shows up as error on computer but can be seen by human eyes and “Brains in Vat," by Boo Rok Lee and Myung Chul Kim based on KAIST's robotic lab’s materials and motif. Also, “The May of My Life” by Professor Myung Seok Kim’s lab reminds us of the relationship between robot and human.
President Myung Seok Kim said, “The range of content in cultural art will inspire students’ imagination.” He continued, “I hope this exhibition will awaken both scientific ideas and artistic sense.”
The opening ceremony of the exhibition will be held from 14:00, 21 November. The “Artificial Brain, Robots Evolve” exhibition is hosted by the Daejeon Museum of Art and sponsored by National Museum of Modern and Contemporary Art and Soma Museum.
Pictures from top to bottom are Cloud Face, Brains in Vat, The May of My Life_1, and The May of My Life_2.
2014.11.21 View 7311 -
The 2014 Wearable Computer Competition Takes Place at KAIST
“This is a smart wig for patients who are reluctant to go outdoors because their hair is falling out from cancer treatment.”
A graduate student from Sungkyunkwan University, Jee-Hoon Lee enthusiastically explains his project at the KAIST KI Building where the 2014 Wearable Computer Competition was held. He said, “The sensor embedded inside the wig monitors the heart rate and the body temperature, and during an emergency, the device warns the patient about the situation. The product emphasizes two aspects; it notifies the patient in emergency situations, and it encourages patients to perform outdoor activities by enhancing their looks.”
The the tenth anniversary meeting of the 2014 Wearable Computer Competition took place at the KAIST campus on November 13-14, 2014.
A wearable computer is a mobile device designed to be put on the body or clothes so that a user can comfortably use it while walking. Recently, these devices that are able to support versatile internet-based services through smartphones are receiving a great deal of attention.
Wearable devices have been employed in two categorizes: health checks and information-entertainment. In this year’s competition, six healthcare products and nine information-entertainment products were exhibited.
Among these products, participants favored a smart helmet for motorcycle drivers. The driver can see through a rear camera with a navigation screen of the smartphone and text messages through the screen installed in the front glass of the helmet. Another product included a uniform that can control presentation slides by means of motion detection and voice recognition technology. Yet another popular device offered an insole to guide travelers to their destination with the help of motion sensors.
The chairman of the competition, Professor Hoi-Jun Yoo from the Department of Electrical Engineering at KAIST said, “Wearable devices such as smart watches, glasses, and clothes are gaining interest these days. Through this event, people will have a chance to look at the creativity of our students through the display of their wearable devices. In turn, these devices will advance computer technology.”
The third annual wearable computer workshop on convergence technology of wearable computers followed the competition. In the workshop, experts from leading information technology companies such as Samsung Electronics, LG Electronics, and KT Corporation addressed the convergence technology of wearable computers and trends in the field.
2014.11.19 View 9483