Receive KAIST news by email!
Type your e-mail address here.
by recently order
by view order
Every Moment of Ultrafast Chemical Bonding Now Captured on Film
- The emerging moment of bond formation, two separate bonding steps, and subsequent vibrational motions were visualized. - < Emergence of molecular vibrations and the evolution to covalent bonds observed in the research. Video Credit: KEK IMSS > A team of South Korean researchers led by Professor Hyotcherl Ihee from the Department of Chemistry at KAIST reported the direct observation of the birthing moment of chemical bonds by tracking real-time atomic positions in the molecule. Professor Ihee, who also serves as Associate Director of the Center for Nanomaterials and Chemical Reactions at the Institute for Basic Science (IBS), conducted this study in collaboration with scientists at the Institute of Materials Structure Science of High Energy Accelerator Research Organization (KEK IMSS, Japan), RIKEN (Japan), and Pohang Accelerator Laboratory (PAL, South Korea). This work was published in Nature on June 24. Targeted cancer drugs work by striking a tight bond between cancer cell and specific molecular targets that are involved in the growth and spread of cancer. Detailed images of such chemical bonding sites or pathways can provide key information necessary for maximizing the efficacy of oncogene treatments. However, atomic movements in a molecule have never been captured in the middle of the action, not even for an extremely simple molecule such as a triatomic molecule, made of only three atoms. Professor Ihee's group and their international collaborators finally succeeded in capturing the ongoing reaction process of the chemical bond formation in the gold trimer. "The femtosecond-resolution images revealed that such molecular events took place in two separate stages, not simultaneously as previously assumed," says Professor Ihee, the corresponding author of the study. "The atoms in the gold trimer complex atoms remain in motion even after the chemical bonding is complete. The distance between the atoms increased and decreased periodically, exhibiting the molecular vibration. These visualized molecular vibrations allowed us to name the characteristic motion of each observed vibrational mode." adds Professor Ihee. Atoms move extremely fast at a scale of femtosecond (fs) ― quadrillionths (or millionths of a billionth) of a second. Its movement is minute in the level of angstrom equal to one ten-billionth of a meter. They are especially elusive during the transition state where reaction intermediates are transitioning from reactants to products in a flash. The KAIST-IBS research team made this experimentally challenging task possible by using femtosecond x-ray liquidography (solution scattering). This experimental technique combines laser photolysis and x-ray scattering techniques. When a laser pulse strikes the sample, X-rays scatter and initiate the chemical bond formation reaction in the gold trimer complex. Femtosecond x-ray pulses obtained from a special light source called an x-ray free-electron laser (XFEL) were used to interrogate the bond-forming process. The experiments were performed at two XFEL facilities (4th generation linear accelerator) that are PAL-XFEL in South Korea and SACLA in Japan, and this study was conducted in collaboration with researchers from KEK IMSS, PAL, RIKEN, and the Japan Synchrotron Radiation Research Institute (JASRI). Scattered waves from each atom interfere with each other and thus their x-ray scattering images are characterized by specific travel directions. The KAIST-IBS research team traced real-time positions of the three gold atoms over time by analyzing x-ray scattering images, which are determined by a three-dimensional structure of a molecule. Structural changes in the molecule complex resulted in multiple characteristic scattering images over time. When a molecule is excited by a laser pulse, multiple vibrational quantum states are simultaneously excited. The superposition of several excited vibrational quantum states is called a wave packet. The researchers tracked the wave packet in three-dimensional nuclear coordinates and found that the first half round of chemical bonding was formed within 35 fs after photoexcitation. The second half of the reaction followed within 360 fs to complete the entire reaction dynamics. They also accurately illustrated molecular vibration motions in both temporal- and spatial-wise. This is quite a remarkable feat considering that such an ultrafast speed and a minute length of motion are quite challenging conditions for acquiring precise experimental data. In this study, the KAIST-IBS research team improved upon their 2015 study published by Nature. In the previous study in 2015, the speed of the x-ray camera (time resolution) was limited to 500 fs, and the molecular structure had already changed to be linear with two chemical bonds within 500 fs. In this study, the progress of the bond formation and bent-to-linear structural transformation could be observed in real time, thanks to the improvement time resolution down to 100 fs. Thereby, the asynchronous bond formation mechanism in which two chemical bonds are formed in 35 fs and 360 fs, respectively, and the bent-to-linear transformation completed in 335 fs were visualized. In short, in addition to observing the beginning and end of chemical reactions, they reported every moment of the intermediate, ongoing rearrangement of nuclear configurations with dramatically improved experimental and analytical methods. They will push this method of 'real-time tracking of atomic positions in a molecule and molecular vibration using femtosecond x-ray scattering' to reveal the mechanisms of organic and inorganic catalytic reactions and reactions involving proteins in the human body. "By directly tracking the molecular vibrations and real-time positions of all atoms in a molecule in the middle of reaction, we will be able to uncover mechanisms of various unknown organic and inorganic catalytic reactions and biochemical reactions," notes Dr. Jong Goo Kim, the lead author of the study. Publications: Kim, J. G., et al. (2020) ‘Mapping the emergence of molecular vibrations mediating bond formation’. Nature. Volume 582. Page 520-524. Available online at https://doi.org/10.1038/s41586-020-2417-3 Profile: Hyotcherl Ihee, Ph.D. Professor email@example.com http://time.kaist.ac.kr/ Ihee Laboratory Department of Chemistry KAIST https://www.kaist.ac.kr Daejeon 34141, Korea (END)
Two Alumni Win the Korea Best Scientist and Technologist Awards
Vice Chairman Ki-Nam Kim (Left) and Distinguished Professor Sukbok Chang (Right) <ⓒ Photo by MSIT and KOFST> Distinguished KAIST Professor Sukbok Chang from the Department of Chemistry and Vice Chairman Ki-Nam Kim of Samsung Electronics were selected as the winners of the “2019 Korea Best Scientist and Technologist Awards” by the Ministry of Science and ICT (MSIT) and the Korean Federation of Science and Technology Societies (KOFST). The awards, which were first handed out in 2003, are the highest honor bestowed to the two most outstanding scientists in Korea every year, and this year’s awardees are of greater significance as they are both KAIST alumni. Professor Chang was recognized for his pioneering achievements and lifetime contributions to the development of carbon-hydrogen activation strategies, especially for carbon-carbon, carbon-nitrogen, and carbon-oxygen formations. His research group has also been actively involved in the development of highly selective catalytic systems allowing the controlled defunctionalization of bio-derived platform substrates under mild conditions, and opening a new avenue for the utilization of biomass-derived platform chemicals. The results of his study have been introduced worldwide through many prestigious journals including Science, Nature Chemistry, and Nature Catalysis, making him one of the world's top 1% researchers by the number of references made to his papers by his peers over four consecutive years from 2015 to 2018. Vice Chairman Kim, who received his M.E. degree from KAIST’s School of Electrical Engineering in 1983, has been credited with playing a leading role in the development of system semiconductors. The awards were conferred on July 4 at the opening ceremony of the 2019 Korea Science and Technology Annual Meeting. (END)
Center for Industrial Future Strategy Takes Off at KAIST
Professor Ju, to Receive Grants from HFSP
(Professor Young Seok Ju) Professor Young Seok Ju from the Graduate School of Medical Science and Engineering was selected as a young investigator to receive research funds from the Human Frontiers Science Program. The Human Frontiers Science Program (HFSP) was founded in 1989 with members of the G7 and European Union to stimulate innovative research in the field of life sciences. Professor Ju placed third out of the eight teams that were selected from 158 applicants representing 60 countries. He is now the fourth Korean to receive a research grant as a young investigator. Professor Jae Kyoung Kim from the Department of Mathematical Sciences also received this prize last year, hence KAIST has produced grant recipients for two consecutive years. Professor Ju is a medical doctor specializing in cancer genomics and computer biology. He has been studying somatic mutations and their functional consequences in human cancer in a bioinformatics way. He has published papers in international journals including Nature, Science, Genome Research, and Journal of Clinical Oncology. With a title ‘Tracing AID/APOBEC- and MSI-mediated hyper-mutagenesis in the clonal evolution of gastric cancer,’ Professor Ju will receive 1.05 million dollars for three years along with Professor Bon-Kyoung Koo from the Institute of Molecular Biotechnology at Austrian Academy of Sciences, and Sinppert Hugo from University Medical Center Utrecht. Professor Ju said, “As a young investigator, it is my great honor to receive this research fund from this organization. Through this internationally collaborative research, I will carry out groundbreaking research to understand the pathophysiology of cancers at a molecular level.”
KAIST Professor Named International Research Grant Reviewer
Prof. Kwang-Hyun Cho of the Department of Bio and Brain Engineering, KAIST, was appointed as a research grant review committee member of the international Human Frontier Science Program (HFSP) for 2008-2009, university authorities reported. The HFSP is a funding agency that supports international collaboration in interdisciplinary, basic research in the life sciences. It was initiated in 1989 by G7 countries as the sole funding program for international researches in neuroscience and molecular biology. The HFSP now has a membership of 35 countries and Korea joined the program in 2004. Prof. Cho will be responsible for reviewing grant applications in the field of systems biology. Prof. Cho received B.S., M.S. and Ph.D. degrees in electrical engineering from KAIST in 1993, 1995, and 1998, respectively. He has been working as a director of the KAIST Institute for the BioCentury and KAIST"s Laboratory for Systems Biology and Bio-Inspired Engineering. He has been serving on editorial advisory boards of various international science journals, including Systems and Synthetic Biology (Springer, Netherlands, from 2006), BMC Systems Biology (BMC, London, U.K., from 2007) and Gene Regulation and Systems Biology (Libertas Academica, New Zealand, from 2007). He is a senior member of the Engineering in Medicine and Biology Society (EMBS) affiliated with the Institute of Electronics and Electrical Engineers (IEEE). His research interests cover the areas of systems science with bio-medical applications, especially systems biology and bio-inspired engineering based on molecular systems biology.
Prof. Bien Named IFSA Fuzzy Fellow
Prof. Bien Named IFSA Fuzzy Fellow Zeungnam Bien, a professor of Electrical Engineering, has been named a Fuzzy Fellow of the International Fuzzy Systems Association (IFSA). IFSA Fuzzy Fellows are named by the Fuzzy Fellows Committee based on the degree of technical contributions to the fuzzy set and its relevant fields and the degree of contribution for the establishment of fundaments in the field of advanced applied technologies development and fuzzy fields. IFSA has named total 36 fellows since its first one at the world congress in Prague in 1997. Professor Bien has worked as the chairman of the IFSA and will be officially named a Fuzzy Fellowship at the IFSA World Congress at Cancun, Mexico in June.
KAIST tech-clinic center opens
- Consists of total 124 staffs including KAIST professors, experts from state-run institutes in Daedeok Innopolis, etc. - Introduce the patient treatment system of general hospitals and provide the services of diagnosis, treatment, and later management of small and medium-sized venture enterprises A tech-clinic center is opened in KAIST to solve technical problems of enterprises in Daedeok Innopolis. KAIST (President Nam Pyo Suh) and Daedeok Innopolis (President&CEO In Chul Park) held the opening ceremony of ‘Daedeok Innopolis-designated KAIST tech-clinic center’ at the High-tech Venture Hall in KAIST, 5:00 p.m. Monday, August 28. KAIST tech-clinic center consists of total 124 staffs including KAIST professors and researchers, experts from state-run institutes in Daedeok Innopolis, etc. The staffs will take charge of general diagnosis and treatment in the fields of Information Communication, BioTechnologies, Nano-Technologies, Environmental Engineering, Management, Design, and so on. The tech-clinic center, upon the request by small and medium-sized enterprises, will dispatch the staffs in the corresponding field to check the state of the enterprises and provide assistance to solve problems in technology development and researches. The center plans to transfer technologies that enterprises need and solve long-term tasks through joint/ entrusted researches. The center will also perform treatments in the fields of management, law, and accounting of enterprises in association with company founding and management consultation project, which is being promoted by Daedeok Innopolis. Unlike the existing consulting institutes that put a high value on consultation, the center is featured with its distinguished way of running that it will analyze the causes of problems, find fundamental solutions, and perform even later management. An official from KAIST said, “Considering various circumstances, it’s not easy for individual enterprises to find suitable experts in the corresponding fields and request proper solutions to settle their problems. That’s the reason why KAIST has promoted this project. KAIST hopes many enterprises in Daedeok Innopolis based on the cutting-edge technologies will gain substantial assistance from this center.” An official from Daedeok Innopolis said, “In order to provide practical supports, the treatment will be carried out in preliminary/ routine/ expert phases. Also, it is planned to strengthen regular omnidirectional support services for enterprises in association with the internet web call center, etc.”
마지막 페이지 1
KAIST, 291 Daehak-ro, Yuseong-gu, Daejeon 34141, Republic of Korea
Copyright(C) 2020, Korea Advanced Institute of Science and Technology,
All Rights Reserved.