Receive KAIST news by email!
Type your e-mail address here.
by recently order
by view order
Breastfeeding Helps Prevent Mothers from Developing Diabetes after Childbirth
A team of South Korean researchers found that lactation can lower the incidence and reduce the risk of maternal postpartum diabetes. The researchers identified that lactation increases the mass and function of pancreatic beta cells through serotonin production. The team suggested that sustained improvements in pancreatic beta cells, which can last for years even after the cessation of lactation, improve mothers’ metabolic health in addition to providing health benefits for infants. Pregnancy imposes a substantial metabolic burden on women through weight gain and increased insulin resistance. Various other factors, including a history of gestational diabetes, maternal age, and obesity, further affect women’s risk of progressing to diabetes after delivery, and the risk of postpartum diabetes increases more in women who have had gestational diabetes and/or repeated deliveries. Diabetes-related complications include damage to blood vessels, which can lead to cardiovascular and cerebrovascular diseases such as heart attack and stroke, and problems with the nerves, eyes, kidneys, and many more. Since diabetes can pose a serious threat to mothers’ metabolic health, the management of maternal metabolic risk factors is important, especially in the peripartum period. Previous epidemiological studies have reported that lactation reduces the risk of postpartum diabetes, but the mechanisms underlying this benefit have remained elusive. The study, published in Science Translational Medicine on April 29, explains the biology underpinning this observation on the beneficial effects of lactation. Professor Hail Kim from the Graduate School of Medical Science and Engineering at KAIST led and jointly conducted the study in conjunction with researchers from the Seoul National University Bundang Hospital (SNUBH) and Chungnam National University (CNU) in Korea, and the University of California, San Francisco (UCSF) in the US. In their study, the team observed that the milk-secreting hormone ‘prolactin’ in lactating mothers not only promotes milk production, but also plays a major role in stimulating insulin-secreting pancreatic beta cells that regulate blood glucose in the body. The researchers also found that ‘serotonin’, known as a chemical that contributes to wellbeing and happiness, is produced in pancreatic beta cells during lactation. Serotonin in pancreatic beta cells act as an antioxidant and reduce oxidative stress, making mothers’ beta cells healthier. Serotonin also induces the proliferation of beta cells, thereby increasing the beta cell mass and helping maintain proper glucose levels. The research team conducted follow-up examinations on a total of 174 postpartum women, 85 lactated and 99 non-lactated, at two months postpartum and annually thereafter for at least three years. The results demonstrated that mothers who had undergone lactation improved pancreatic beta cell mass and function, and showed improved glucose homeostasis with approximately 20mg/dL lower glucose levels, thereby reducing the risk of postpartum diabetes in women. Surprisingly, this beneficial effect was maintained after the cessation of lactation, for more than three years after delivery. Professor Kim said, “We are happy to prove that lactation benefits female metabolic health by improving beta cell mass and function as well as glycemic control.” “Our future studies on the modulation of the molecular serotonergic pathway in accordance with the management of maternal metabolic risk factors may lead to new therapeutics to help prevent mothers from developing metabolic disorders,” he added. This work was supported by grants from the National Research Foundation (NRF) and the National Research Council of Science and Technology (NST) of Korea, the National Institutes of Health (NIH), the Larry L. Hillblom Foundation, and the Health Fellowship Foundation. Image credit: Professor Hail Kim, KAIST Image usage restrictions: News organizations may use or redistribute this image, with proper attribution, as part of news coverage of this paper only. Publication: Moon, J. H et al. (2020) ‘Lactation improves pancreatic β cell mass and function through serotonin production.’ Science Translational Medicine, 12, eaay0455. Available online at https://doi.org/10.1126/scitranslmed.aay0455 Profile: Hail Kim, MD, PhD firstname.lastname@example.org Associate Professor Graduate School of Medical Science and Engineering (GSMSE) Korea Advanced Institute of Science and Technology (KAIST) Profile: Hak Chul Jang, MD, PhD email@example.com Professor Division of Endocrinology and Metabolism Seoul National University Bundang Hospital (SNUBH) President Korean Diabetes Association Profile: Joon Ho Moon, MD, PhD firstname.lastname@example.org Clinical Fellow Division of Endocrinology and Metabolism SNUBH Profile: Hyeongseok Kim, MD, PhD email@example.com Assistant Professor Chungnam National University (CNU) Profile: Professor Michael S. German, MD Michael.German@ucsf.edu Professor Diabetes Center University of California, San Francisco (UCSF) (END)
Ultra-Fast and Ultra-Sensitive Hydrogen Sensor
(From left: Professor Kim, Ph.D. candidate Koo, and Professor Penner) A KAIST team made an ultra-fast hydrogen sensor that can detect hydrogen gas levels under 1% in less than seven seconds. The sensor also can detect hundreds of parts per million levels of hydrogen gas within 60 seconds at room temperature. A research group under Professor Il-Doo Kim in the Department of Materials Science and Engineering at KAIST, in collaboration with Professor Reginald M. Penner of the University of California-Irvine, has developed an ultra-fast hydrogen gas detection system based on a palladium (Pd) nanowire array coated with a metal-organic framework (MOF). Hydrogen has been regarded as an eco-friendly next-generation energy source. However, it is a flammable gas that can explode even with a small spark. For safety, the lower explosion limit for hydrogen gas is 4 vol% so sensors should be able to detect the colorless and odorless hydrogen molecule quickly. The importance of sensors capable of rapidly detecting colorless and odorless hydrogen gas has been emphasized in recent guidelines issued by the U.S. Department of Energy. According to the guidelines, hydrogen sensors should detect 1 vol% of hydrogen in air in less than 60 seconds for adequate response and recovery times. To overcome the limitations of Pd-based hydrogen sensors, the research team introduced a MOF layer on top of a Pd nanowire array. Lithographically patterned Pd nanowires were simply overcoated with a Zn-based zeolite imidazole framework (ZIF-8) layer composed of Zn ions and organic ligands. ZIF-8 film is easily coated on Pd nanowires by simple dipping (for 2–6 hours) in a methanol solution including Zn (NO3)2·6H2O and 2-methylimidazole. (This cover image depicts lithographically-patterned Pd nanowires overcoated with a Zn-based zeolite imidazole framework (ZIF-8) layer.) As synthesized ZIF-8 is a highly porous material composed of a number of micro-pores of 0.34 nm and 1.16 nm, hydrogen gas with a kinetic diameter of 0.289 nm can easily penetrate inside the ZIF-8 membrane, while large molecules (> 0.34 nm) are effectively screened by the MOF filter. Thus, the ZIF-8 filter on the Pd nanowires allows the predominant penetration of hydrogen molecules, leading to the acceleration of Pd-based H2 sensors with a 20-fold faster recovery and response speed compared to pristine Pd nanowires at room temperature. Professor Kim expects that the ultra-fast hydrogen sensor can be useful for the prevention of explosion accidents caused by the leakage of hydrogen gas. In addition, he expects that other harmful gases in the air can be accurately detected through effective nano-filtration by using of a variety of MOF layers. This study was carried out by Ph.D. candidate Won-Tae Koo (first author), Professor Kim (co-corresponding author), and Professor Penner (co-corresponding author). The study has been published in the online edition of ACS Nano, as the cover-featured image for the September issue. Figure 1. Representative image for this paper published in ACS Nano, August, 18. Figure 2. Images of Pd nanowire array-based hydrogen sensors, scanning electron microscopy image of a Pd nanowire covered by a metal-organic framework layer, and the hydrogen sensing properties of the sensors. Figure 3. Schematic illustration of a metal-organic framework (MOF). The MOF, consisting of metal ions and organic ligands, is a highly porous material with an ultrahigh surface area. The various structures of MOFs can be synthesized depending on the kinds of metal ions and organic ligands.
Dr. Zi Jing Wong Named 2017 Jeong Hun Cho Awardee
(Photo caption: The 2017 Jeong Hun Cho Scholarship recipients pose with President Shin (left photo) and Dr. Zi Jing Wong, the recipient of the 2017 Jeong Hun Cho Award) Dr. Zi Jing Wong, a postdoctoral scholar at the University of California, Berkeley was named the 2017 recipient of the Jeong Hun Cho Award. The award recognizes outstanding young scientists in the field of aerospace engineering annually. The recipient receives a 20 million KRW prize. The Award Committee said that Dr. Wong who earned his MS at KAIST Department of Aerospace Engineering is a rising scholar in the fields of optic meta materials, photonics, imaging, among others. He has published five papers on the realization of a zero refractive index and the control of a refractive index, as well as the realization of a 3D invisibility cloak in Science and Nature Photonics in 2014 and 2015. Dr. Wong also swept the best paper awards from many international academic societies including the US Materials Research Society, IEEE, SPIE, and Metamaterials Congress in 2015. He finished his Ph.D. at the University of California, Berkeley. The Award Committee also named three recipients of the Jeong Hun Cho Scholarship: Ph.D. candidate Hyon-Tak Kim of the Department of Aerospace Engineering at KAIST, Ph.D. candidate Ho-Song Park from the Department of Mechanical Engineering at Korea University, and Hyong-Jin Choi of Kongju National University High School. The award was endowed by the family of the late Ph.D. candidate Jeong Hun Cho who died in a rocket lab accident in the Department of Aerospace Engineering in 2003. Cho was posthumously conferred an honorary doctorate degree. In memory of Cho, his father established the ‘Jeong Hun Cho Award and Scholarship.’ The scholarship annually selects three young scholars from Cho’s alma maters of KAIST, Korea University, and Kongju National University High School.
Leon Chua, the founder of the circuit theory called "memristor," gave a talk at KAIST
Dr. Leon Ong Chua is a circuit theorist and professor in the Department of Electrical Engineering and Computer Sciences at the University of California, Berkeley. He visited KAIST on April 16, 2014 and gave a talk entitled “Memristor: New Device with Intelligence.” Dr. Chua contributed to the development of nonlinear circuit theory and cellular neural networks (CNN). He was also the first to conceive of memristor which combines the characteristics of memory and resistor. Memristor is a type of resistor, remembering the direction and charge of electrical current that has previously flowed through the resistor. In other words, memristor can retain memory without power. Today, memristor is regarded as the fourth fundamental circuit element, together with capacitors, inductors, and resistors. In 2008, researchers at Hewlett-Packard (HP) Labs developed the first working model of memristor, which was reported in Nature (May 1st , 2008). In addition, Dr. Chua is an IEEE fellow and has received numerous awards including the IEEE Kirchhoff Award, the IEEE Neural Network Pioneer Award, the IEEE Third Millennium Medal, and the Top 15 Most Cited Author in Engineering Award.
"Modeling and Simulation of Discrete Event Systems" by Professor Byoung-Kyu Choi, Selected as Textbook by UC Berkeley
The book, "Modeling and Simulation of Discrete Event Systems," written by Professor Byoung-Kyu Choi from the Department of Industrial and Systems Engineering at KAIST, was selected as a textbook for the Department of Industrial Engineering at the University of California in Berkeley (UC Berkeley).It was published based on professor Choi’s lecture notes and has been used as a textbook for both undergraduate and graduate students at KAIST.Professor Lee W. Schruben from the Department of Industrial Engineering at UC Berkeley said, “It was selected as a textbook for the discrete event simulation course since it shows outstanding educational methodology as well as academic values.”Professor Choi said, “This is the first case of an American university choosing a Korean industrial engineering publication as a textbook. We should be proud of the high evaluation of KAIST’s Industrial and Systems Engineering Department.” The School of Engineering in UC Berkeley was ranked third in the Times Higher Education World University Rankings in 2013.
KAIST signs a Cooperation Agreement with University of California, Irvine
On April 6th, KAIST signed a cooperation memorandum of understanding (MOU) establishing academic exchanges of faculty and students with the University of California, Irvine (UC Irvine). The MOU states that the collaboration between both universities will promote the exchange of faculty and students, as well as joint research. Following UC Los Angeles (UCLA), Irvine became the second UC campus to make the exchange agreement with KAIST. UC Irvine was founded in 1965, and is known as a prestigious public university composed of 13 departments, including colleges of arts, biological sciences, engineering, and humanities. The ceremony was attended by KAIST President, Sung-Mo Kang, and UC Irvine President, Michael V. Drake, as well as Suk-Hee Kang, the former Mayor of Irvine. KAIST President Sung-Mo "Steve" Kang (left) and President of UC Irvine Michael Drake (right) shake hands after signing the Cooperation MOU.
High-resolution Atomic Imaging of Specimens in Liquid Observed by Transmission Electron Microscopes Using Graphene Liquid Cells
Looking into specimens in liquid at the atomic level to understand nanoscale processes so far regarded as impossible to witnessThe Korea Advanced Institute of Science and Technology (KAIST) announced that a research team from the Department of Materials Science and Engineering has developed a technology that enables scientists and engineers to observe processes occurring in liquid media on the smallest possible scale which is less than a nanometer. Professor Jeong Yong Lee and Researcher Jong Min Yuk, in collaboration with Professors Paul Alivisatos’s and Alex Zettl’s groups at the University of California, Berkeley, succeeded in making a graphene liquid cell or capsule, confining an ultra-thin liquid film between layers of graphene, for real-time and in situ imagining of nanoscale processes in fluids with atomic-level resolution by a transmission electron microscope (TEM). Their research was published in the April 6, 2012 issue of Science. (http://www.sciencemag.org/content/336/6077/61.abstract) The graphene liquid cell (GLC) is composed of two sheets of graphene sandwiched to create a sealed chamber where a platinum growth solution is encapsulated in the form of a thin slice. Each graphene layer has a thickness of one carbon atom, the thinnest membrane that has ever been used to fabricate a liquid cell required for TEM. The research team peered inside the GLC to observe the growth and dynamics of platinum nanocrystals in solution as they coalesced into a larger size, during which the graphene membrane with the encapsulated liquid remained intact. The researchers from KAIST and the UC Berkeley identified important features in the ongoing process of the nanocrystals’ coalescence and their expansion through coalescence to form certain shapes by imaging the phenomena with atomic-level resolution. Professor Lee said, “It has now become possible for scientists to observe what is happening in liquids on an atomic level under transmission electron microscopes.” Researcher Yuk, one of the first authors of the paper, explained his research work. “This research will promote other fields of study related to materials in a fluid stage including physical, chemical, and biological phenomena at the atomic level and promises numerous applications in the future. Pending further studies on liquid microscopy, the full application of a graphene-liquid-cell (GLC) TEM to biological samples is yet to be confirmed. Nonetheless, the GLC is the most effective technique developed today to sustain the natural state of fluid samples or species suspended in the liquid for a TEM imaging.” The transmission electron microscope (TEM), first introduced in the 1930s, produces images at a significantly higher resolution than light microscopes, allowing users to examine the smallest level of physical, chemical, and biological phenomena. Observations by TEM with atomic resolution, however, have been limited to solid and/or frozen samples, and thus it has previously been impossible to study the real time fluid dynamics of liquid phases. TEM imaging is performed in a high vacuum chamber in which a thin slice of the imaged sample is situated, and an electron beam passes through the slice to create an image. In this process, a liquid medium, unlike solid or frozen samples, evaporates, making it difficult to observe under TEM. Attempts to produce a liquid capsule have thus far been made with electron-transparent membranes of such materials as silicon nitride or silicon oxide; such liquid capsules are relatively thick (tens to one hundred nanometers), however, resulting in poor electron transmittance with a reduced resolution of only a few nanometers. Silicon nitride is 25 nanometers thick, whereas graphene is only 0.34 nanometers. Graphene, most commonly found in bulk graphite, is the thinnest material made out of carbon atoms. It has unique properties such as mechanical tensile strength, high flexibility, impermeability to small molecules, and high electrical conductivity. Graphene is an excellent material to hold micro- and nanoscopic objects for observation in a transmission electron microscope by minimizing scattering of the electron beam that irradiates a liquid sample while reducing charging and heating effects. ### Figure 1. Schematic illustration of graphene liquid cells. Sandwiched two sheets of graphene encapsulate a platinum growth solution. Figure 2. In-situ TEM observation of nanocrystal growth and shape evolution. TEM images of platinum nanocrystal coalescence and their faceting in the growth solution.
Int'l Telematic Music Concert for Peace to Take Place on Nov. 20
Renowned musicians in five international locations perform new contemporary music works for peace through a real-time performance on the internet. Local audiences in Seoul, Banff, New York, San Diego and Belfast will also have a chance to hear a program. In Seoul, the "International Telematic Music Concert for Peace" will be held at the LeeHaeRang Art Theater, Dongguk University, in Seoul on Nov. 20 at 9:30 a.m., under the presentation of KAIST"s Graduate School of Culture Technology and MARTE Lab, Dongguk University. Telematic music is real-time performance via the internet by musicians in different geographic locations. The program of the concert includes "Hope"s Dream" by Mark Dresser and Sarah Weaver; "Disparate Bodies" by Pedro Rebelo, "Rock, Paper, Scissors" by Chris Chafe. The Korean act to be performed is "Green-colored Harmony" by Jun Kim. In addition to the two Korean universities, the World Association of Former United Nations Internes and Fellows (WAFUNIF), University of California San Diego, the Banff Center of Canada and Queen"s University in Belfast are participating in the project. The performance will take place on high-bandwidth internet with JackTrip audio software developed by Chris Chafe and Access Grid video software developed at Argonne National Laboratory. "Connecting the five different cities together through super-speed Internet network and transmitting sound and images in real time is challenging technically. But, we also expect that more exciting results will be created in the course of transforming the sound into visual images," said Woon-Seung Yeo, a professor of the Graduate School of Culture Technology, who was responsible for visuals in the project.
KAIST Team Identifies Nano-scale Origin of Toughness in Rare Earth-added Silicon Carbide
A research team led by Prof. Do-Kyung Kim of the Department of Materials Science and Engineering of KAIST has identified the nano-scale origin of the toughness in rare-earth doped silicon carbide (RE-SiC), university sources said on Monday (Oct. 6). The research was conducted jointly with a U.S. team headed by Prof. R. O. Ritchie of the Department of Materials Science and Engineering, University of California, Berkeley. The findings were carried in the online edition of Nano Letters published by the American Chemical Association. Silicon carbide, a ceramic material known to be one of the hardest substances, are potential candidate materials for many ultrahigh-temperature structural applications. For example, if SiC, instead of metallic alloys, is used in gas-turbine engines for power generation and aerospace applications, operating temperatures of many hundred degrees higher can be obtained with a consequent dramatic increase in thermodynamic efficiency and reduced fuel consumption. However, the use of such ceramic materials has so far been severely limited since the origin of the toughness in RE-SiC remained unknown thus far. In order to investigate the origin of the toughness in RE-SiC, the researchers attempted to examine the mechanistic nature of the cracking events, which they found to occur precisely along the interface between SiC grains and the nano-scale grain-boundary phase, by using ultrahigh-resolution transmission electron microscopy and atomic-scale spectroscopy. The research found that for optimal toughness, the relative elastic modulus across the grain-boundary phase and the interfacial fracture toughness are the most critical material parameters; both can be altered with appropriate choice of rare-earth elements. In addition to identifying the nano-scale origin of the toughness in RE-SiC, the findings also contributed to precisely predicting how the use of various rare-earth elements lead to difference in toughness. University sources said that the findings will significantly advance the date when RE-SiC will replace metallic alloys in gas-turbine engines for power generation and aerospace applications.
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.