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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 8854 -
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 13696 -
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 11720 -
President Steve Kang will serve as the Chairman of Global Agenda Council on the Future of Electronics of the World Economic Forum
President Steve Kang of KAIST has been appointed to the Chairman of the Global Agenda Council (GAC) on the Future of Electronics of the World Economic Forum (WEF). He will serve the position for two years until September 2016.
President Kang and WEF council members co-hosted, with the government of the United Arab Emirates (UAE), the Future Circles Initiative, a future-focused, innovative brainstorming conference to help find strategies and ideas for the development of UAE. The conference took place on November 11-12, 2014 at the Mina Al Salam Hotel in Dubai.
WEF has about 80 GACs. Each council consists of 15 experts and thought leaders from the academia, industry, government, business, and non-profit sector and deals with specific issues that are important and relevant to the global community such as ageing, artificial intelligence and robotics, brain research, food and nutrition security, education, social media, and future of chemicals, advanced materials and biotechnology.
President Kang was recognized for his contribution to the advancement of science and higher education as an engineer, scholar, and professor. He led the development of the world’s premier CMOS 32-bit microprocessors while working at the AT&T Bell Laboratories. He also taught and conducted research at the University of California, Santa Cruz, and the University of Illinois, Urbana-Champaign. President Kang served as the chancellor of the University of California at Merced from March 2007 to June 2011.
2014.11.11 View 9314 -
KAIST Registers an Internationally Recognized Standard Patent
A video compression technology, jointly developed by Professor Mun-Chul Kim of the Department of Electrical Engineering at KAIST, the Electronics and Telecommunications Research Institute (ETRI), and the Korean Broadcasting System (KBS), is registered internationally as the standard patent in the next-generation High Efficiency Video Coding (HEVC).
HEVC (H.265) is an international technology standard that compresses large image data for Ultra High Definition (UHD) televisions and smartphones. It has the twice the compression efficiency as that of H.264/AVC which is most commonly used for processing full HD sources. This means that it is able to compress a video file to half the size while maintaining the same image quality.
Although the related market is at a nascent stage, HEVC technology has already been applied to the latest version of televisions and smartphones. Experts predict that the market will grow to USD 200 billion by 2016, and KAIST is expected to receive a royalty payment of USD 9.3 million from this patent.
The International Organization for Standardization (ISO/IEC) established the HEVC standard in January 2013. Also, an international patent pool licensing corporation, MPEG LA announced the HEVC standard patent pool on September 29, 2014.
Professor Joongmyeon Bae, Dean of the Office of University-Industry Cooperation (OUIC) of KAIST, said, “This is an unprecedented case for Korea whereby a core technology developed by a university became an international standard, which has a vast impact on the market.”
President of KAIST, Steve Kang commented, “With its advanced technology, KAIST joined the HEVC standard patent pool as one of the 23 founding members along with Apple, Siemens, and NEC. This is a remarkable achievement.”
Picture 1: Improvements in video compression technology
Picture 2: Comparison of different screen resolutions
2014.10.09 View 12798 -
Development of a Photonic Diode with Light Speed, Single-Direction Transfer
A photonic diode using a nitride semiconductor rod can increase the possibility of developing all-optical integrated circuits, an alternative to conventional integrated circuits.
Professor Yong-Hoon Cho's research team from the Department of Physics, KAIST, developed a photonic diode which can selectively transfer light in one way, using semiconductor rods.
The photonic diode has a diameter of hundreds of nanometers (nm) and a length of few micrometers. This size enables its use in large-scale integration (LSI). The diode’s less sensitivity towards polarized light angle makes it more useful.
In an integrated circuit, a diode controls the flow of electrons. If this diode controls light rather than electrons, data can be transferred at high speed, and its loss is minimized to a greater extent. Since these implementations conserve more energy, this is a very promising future technology.
However, conventional electronic diodes, made up of asymmetric meta-materials or photonic crystalline structures, are large, which makes them difficult to be used in LSI. These diodes could only be implemented under limited conditions due to its sensitivity towards polarized light angle.
The research team used nitride semiconductor rods to develop a highly efficient photonic diode with distinct light intensities from opposite ends.
The semiconductor rod yields different amount of energy horizontally. According to the research team, this is because the width of the quantum well and its indium quantity is continuously controlled.
Professor Cho said, "A large energy difference in a horizontal direction causes asymmetrical light propagation, enabling it to be operated as a photonic diode." He added that “If light, instead of electrons, were adopted in integrated circuits, the transfer speed would be expected as great as that of light.”
The research findings were published in the September 10th issue of Nano Letters as the cover paper.
Under the guidance of Professor Cho, two Ph.D. candidates, Suk-Min Ko and Su-Hyun Gong, conducted this research. This research project was sponsored by the National Research Foundation of Korea and KAIST’s EEWS (energy, environment, water, and sustainability) Research Center.
Figure Description: Computer simulated image of photonic diode made of semiconductor rod implemented in an all-optical integrated circuit
2014.09.23 View 11478 -
Distinguished Professor Sang Yup Lee Participates in the 2014 Summer Davos Forum
Distinguished Professor Sang Yup Lee from the Department of Chemical and Biomolecular Engineering, KAIST, was invited to lead four sessions at the Annual Meeting 2014, the World Economic Forum, also known as the Summer Davos Forum, which was held in Tianjin, China, from September 10th to 12th.
Two of the four sessions Professor Lee participated in were held on September 10th. At the first session entitled “Biotechnology Ecosystem,” he examined with other panelists the future of bioengineering in depth and discussed major policies and industry trends that will be necessary for the development of future biotechnologies.
Professor Lee later attended the “Strategic Shifts in Healthcare” session as a moderator. Issues related to transforming the health industry such as the next-generation genomics, mobile health and telemedicine, and wearable devices and predictive analytics were addressed.
On September 12, Professor Lee joined the “IdeasLab with KAIST” and gave a presentation on nanotechnology. There was a total of ten IdeasLab sessions held at the Summer Davos Forum, and KAIST was the only Korean university ever invited to host this session. In addition to Professor Lee’s presentation, three more presentations were made by KAIST professors on such topics as “Sustainable Energy and Materials” and “Next-generation Semiconductors.”
Lastly, Professor Lee participated in the “Global Promising Technology” session with the World Economic Forum’s Global Agenda Council members. At this session, he explained the selection of the “World’s Top 10 Most Promising Technologies” and “Bio Sector’s Top 10 Technologies” and led discussions about the “2015 Top 10 Technologies” with the council members.
The Davos Forum has been announcing the “World’s Top 10 Most Promising Technologies” since 2012, and Professor Lee has played a key role in the selection while working as the Chairman of Global Agenda Council. The selection results are presented at the Davos Forum every year and have attracted a lot of attention from around the world.
2014.09.15 View 12051 -
Opening of "Education Donation Center" for Knowledge Sharing
KAIST is a leader in knowledge-sharing services for the educationally underprivileged. KAIST held the opening ceremony of the Education Donation Center at its Munji Campus on July 4, 2014 and was appointed as a “2014 Chungcheong-Gangwon province model local education donation center” sponsored by the Education Ministry of Korea and Korea Foundation for the Advancement of Science and Creativity.
The Education Donation Center (EDC) will integrate programs run by the Chungcheong-Gangwon province education donation organizations and introduce them to local chapter organizations. The EDC will recommend new donation organizations to the organizations in need. To ensure efficient donation, the EDC will consult programs of donation organizations. The EDC will also suggest regionally suitable education donation programs. KAIST will provide three staff members, six graduate students, and one to manage the career counselor to the center.
Joo-Sung Lee of the Business & Technology Management Department is the professor in charge of the EDC. He explained, “The center is the medium between the newly participating education donation organizations and the demand organizations. I will invest every effort to provide high-quality educational benefits to educationally underprivileged people."
KAIST has also been running an education service group called ‘Midam Scholarship’, an online education donation group called ‘Chalk’, and science camp programs for youth to establish the sharing and collaboration culture of KAIST.
2014.07.10 View 9268 -
Professor Jae-Kyu Lee Elected to Head the Association for Information Systems
Jae Kyu Lee, HHI (Hyundai Heavy Industries, Co., Ltd.) Chair Professor, College of Business at KAIST, was elected to lead the world major academic society, Association for Information Systems (AIS), from July 2015 to June 2016. Professor Lee will be the first Korean to serve the organization as president. From July 2014 to June 2015, he will serve as president-elect.
Currently, Professor Lee is the Director of EEWS (Energy, Environment, Water, and Sustainability) Research Center at KAIST, focusing on research and development in finding solutions to critical issues facing humanity. He also played a pivotal role in the conclusion of a memorandum of understanding between HHI and KAIST in June 2013 to establish HHI-KAIST EEWS Research Center within the KAIST campus.
The AIS is the premier professional association for individuals and organizations who lead the research, teaching, practice, and study of information systems worldwide.
A news article on his appointment:
Asian Scientist, May 16, 2014
Korean Engineer To Lead The Association For Information Systems
http://www.asianscientist.com/academia/korean-engineer-lead-association-information-systems-2014/
2014.05.19 View 11258 -
Professor Jae-Kyu Lee Elected to Head the Association for Information Systems
Jae Kyu Lee, HHI (Hyundai Heavy Industries, Co., Ltd.) Chair Professor, College of Business at KAIST, has been elected to lead the world major academic society, Association for Information Systems (AIS), from July 2015 to June 2016. Professor Lee will be the first Korean to serve the organization as president. From July 2014 to June 2015, he will serve as president-elect.
Currently, Professor Lee is the Director of EEWS (Energy, Environment, Water, and Sustainability) Research Center at KAIST, focusing on research and development in finding solutions to critical issues facing humanity. He also played a pivotal role in the conclusion of a memorandum of understanding between HHI and KAIST in June 2013 to establish HHI-KAIST EEWS Research Center within the KAIST campus.
The AIS is the premier professional association for individuals and organizations who lead the research, teaching, practice, and study of information systems worldwide.
2014.05.14 View 10337 -
Professor Sang-Yup Lee Named the Winner of the Ho-Am Prize in 2014
The Ho-Am Prize, awarded by Samsung Group’s Ho-Am Foundation, was announced on April 2, 2014 in Seoul. Professor Sang-Yup Lee of Chemical and Biomolecular Engineering at KAIST was among the five recipients.
The prize is presented to Koreans who have made great contributions to the development of Korea in the field of science, engineering, medicine, arts, and philanthropy.
Professor Lee received the award in recognition of his pioneering research on systems metabolic engineering.
For the story written by Korea Joongang Daily, please go to the link below:
Ho-Am Foundation Names Annual Prize Winners
Korea Joongang Daily
April 3, 2014
http://koreajoongangdaily.joins.com/news/article/Article.aspx?aid=2987332
2014.04.03 View 10105 -
High Resolution 3D Blood Vessel Endoscope System Developed
Professor Wangyeol Oh of KAIST’s Mechanical Engineering Department has succeeded in developing an optical imaging endoscope system that employs an imaging velocity, which is up to 3.5 times faster than the previous systems. Furthermore, he has utilized this endoscope to acquire the world’s first high-resolution 3D images of the insides of in vivo blood vessel.
Professor Oh’s work is Korea’s first development of blood vessel endoscope system, possessing an imaging speed, resolution, imaging quality, and image-capture area. The system can also simultaneously perform a functional imaging, such as polarized imaging, which is advantageous for identifying the vulnerability of the blood vessel walls.
The Endoscopic Optical Coherence Tomography (OCT) System provides the highest resolution that is used to diagnose cardiovascular diseases, represented mainly by myocardial infarction.
However, the previous system was not fast enough to take images inside of the vessels, and therefore it was often impossible to accurately identify and analyze the vessel condition. To achieve an in vivo blood vessel optical imaging in clinical trials, the endoscope needed to be inserted, after which a clear liquid flows instantly, and pictures can be taken in only a few seconds.
The KAIST research team proposed a solution for such problem by developing a high-speed, high-resolution optical tomographic imaging system, a flexible endoscope with a diameter of 0.8 mm, as well as a device that can scan the imaging light within the blood vessels at high speed. Then, these devices were combined to visualize the internal structure of the vessel wall.
Using the developed system, the researchers were able to obtain high-resolution images of about 7 cm blood vessels of a rabbit’s aorta, which is similar size to human’s coronary arteries. The tomography scan took only 5.8 seconds, at a speed of 350 scans per second in all three directions with a resolution of 10~35㎛.
If the images are taken every 200 ㎛, like the currently available commercial vascular imaging endoscopes, a 7cm length vessel can be imaged in only one second.
Professor Wangyeol Oh said, “Our newly developed blood vessel endoscope system was tested by imaging a live animal’s blood vessels, which is similar to human blood vessels. The result was very successful.”
“Collaborating closely with hospitals, we are preparing to produce the imaging of an animal’s coronary arteries, which is similar in size to the human heart,” commented Professor Oh on the future clinical application and commercialization of the endoscope system. He added, “After such procedures, the technique can be applied in clinical patients within a few years.”
Professor Oh’s research was supported by the National Research Foundation of Korea and the Global Frontier Project by the Korean government. The research results were published in the 2014 January’s edition of Biomedical Optics Express.
Figure 1: End portion of optical endoscope (upper left)
Figure 2: High-speed optical scanning unit of the endoscope (top right)
Figure 3: High-resolution images of the inside of in vivo animal blood vessels (in the direction of vascular circumference and length)
Figure 4: High-resolution images of the inside of in vivo animal blood vessels (in the direction of the vein depth)
2014.03.25 View 11643