The research team led by Prof. Sungho Park
A new way to confine electromagnetic near-field within a single entity

- Successive publications in top-tier scientific journals in the disciplines of chemistry and nanomaterials
- Structurally unique and complex nanoframes can replace conventional nanoparticles in plasmonics, biosensing, and catalysis

Chemistry PARK, SUNGHO Prof.

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  • The research team led by Prof. Sungho Park ▼ A new way to confine electromagnetic near-field within a single entity

    Chemistry PARK, SUNGHO Prof.

    The research team led by Prof. Sungho Park A new way to confine electromagnetic near-field within a single entity

    Noble metals such as Au and Ag exhibit unique optical properties when their sizes are smaller than the wavelength of light. Surface plasmon resonance, a collective oscillation of conduction free electrons of metallic nanoparticles, is very sensitive to size, shape and dielectric environment and supports strong localized near-field confinement around the metallic nanoparticles. These plasmonic nanoparticles have been widely applied in a myriad of applications including optics, biosensing, catalysis and energy. Although structural-simple nanospheres or nanorods have been extensively used because of their easy-to-use, weak near-field focusing capabilities hindered their effective use for practical applications. In addition, nanoframes that have recently been paid attention show certain limitations in that their large inner spaces do not allow effective interactions with resonant light. Importantly, it is very challenging to produce nanoparticles with uniform size and shape via wet-chemical synthesis because diverse particle-particle interactions are present in a solution-phase. The research team (Nanomaterials Chemistry Lab.) led by Prof. Sungho Park in the department of chemistry, came up with a new idea inspired by ‘Cosmic Bowl*’ and ‘Matryoshka Doll**’and developed a new synthetic method for structurally very complex nanoframes that exhibit strongly enhanced near-field focusing capability. By suggesting a new paradigm in the field of nanoparticle synthesis, the research team’s breakthrough has been appreciated. The team applied rationally-designed multiple chemical steps and realized structural-complex nanoframes with different shapes, sizes, and numbers of nanogaps in a single entity. Importantly, the synthesis method is “rational and on-demand that is different from the conventional “trial-and-error” method, allowing for developing a broad library of unique nanoframes including dimensions (2D, and 3D), order (numbers of frames: 1st, 2nd, 3rd, and 4th), composition (Au, Pt, and Ag), shapes (circular, triangular, hexagonal, cubic, and octahedron), nanogaps shapes (circular, triangular, Y-shape) Using these nanoframes as a building block, the team fabricated superlattice substrates with uniform arrangement and high sensitivity. Their strong plasmonic interactions from inter- and intraparticle coupling allow for a very sensitive SERS-based detection of target molecules and reached pico and attomolar levels of limit of detection. Prof. Sungho Park said, “I am really happy and excited that we developed a new synthetic pathway for designing complex nanoframes that had never been reported before. We believe it is an important step towards new breakthroughs in nanoparticle synthesis and will use nanoframe-based libraries for diverse applications such as chemical/biological sensing, catalysis, plasmonics and energy storage where strong electromagnetic near-field enhancement is important.” This research was supported by the Challengeable Future Defense Technology Research and Development Program through the Agency for Defense Development (ADD) funded by the Defense Acquisition Program Administration (DAPA) in 2022. The results were published in various top-tier journals in the chemistry and materials science discipline, proving the scientific importance. (Nature Communications, Journal of the American Chemical Society, Accounts of Chemical Research, ACS Nano, Nano Letters, etc.) *(Title : Plasmonic All-Frame-Faceted Octahedral Nanoframes with Eight Engraved Y-Shaped Hot Zones, 제 1저자 : 김정원, 저널명 : ACS Nano (IF:18.027), 게재일 : 2022년 6월 28일) *(Title : All-Hot-Spot Bulk SERS substrates: Attomolar Detection of Adsorbates with Designer Plasmonic Nanoparticles, 제 1저자 : Qiang Zhao, 저널명 : Journal of American Chemical Society (IF:16.383), 게재일 : 2022년 7월 27일) *(Title : Three-dimensional Nanoframes with Dual Rims as Nanoprobes for Biosensing, 제 1저자 : Hajir Hilal, 저널명 : Nature Communications (IF:17.694), 게재일 : 2022년 8월 16일) *(Title : Synthesis of Pt Double-Walled Nanoframes with Well-Defined and Controllable Facets, 제 1저자 : MohammadNavid Haddadnezhad, 저널명 : ACS Nano (IF:18.027), 게재일 : 2022년 12월 27일) *(Title: Multi-Layered PtAu Nanoframes and their Light-Enhanced Electrocatalytic Activity via Plasmonic Hot Spots, 제 1저자 : 이수현 저널명 : Small (IF:15.153), 게재일 : 2023년 1월 8일) *(Title : Multiple Stepwise Synthetic Pathways toward Complex Plasmonic 2D and 3D Nanoframes for Generation of Electromagnetic Hot Zones in a Single Entity, 제 1저자 : 정인섭, 저널명 : Accounts of Chemical Research (IF:24.466), 게재일 : 2023년 2월 7일) *Cosmic Bowl: German mathematician and astronomer, Johannes Kepler proposed the concept of ‘Cosmic Bowl’ that the universe is interconnected by planets comprised of five platonic polygons nesting one in another. **Matryoshka Doll: A set of wooden dolls of decreasing size are nested one inside another and are known as Russian dolls. ※ Title : Multiple Stepwise Synthetic Pathways toward Complex Plasmonic 2D and 3D Nanoframes for Generation of Electromagnetic Hot Zones in a Single Entity (DOI: https://doi.org/10.1021/acs.accounts.2c00670) [Figure 1. 다단계의 2차원 복잡 구조 나노프레임 합성 모식도] [Figure 2. 이중-림을 가지는 나노프레임 합성법, 제작된 입자의 주사전자현미경 이미지 및 균일한 자가조립 기판의 극대화된 전자기장 증강 효과 시뮬레이션] [Figure 3. 금 나노입자 결정면의 에너지 차이를 이용한 선택적 백금 증착 및 금 에칭 기법을 활용하여 다양한 모양을 가지는 백금 기반의 단일 또는 이중림 구조 나노프레임 입자의 이미지] [Accounts of Chemical Research Journal, Feb. Supplementary cover] [ACS Nano Journal 2022 June Front cover]

  • A vacuum-deposited nanoscale ultrathin polymer dielectric for large-area stretchable electronics

    Electronic and Electrical Engineering SON, DONGHEE Prof.

    A vacuum-deposited nanoscale ultrathin polymer dielectric for large-area stretchable electronics

    The joint research team of assistant professor Donghee Son at Sungkyunkwan University (SKKU), professor Dae-Hyeong Kim at Seoul National University (SNU), and professor Sung Gap Im at Korea Advanced Institute of Science and Technology (KAIST) developed a soft, stretchable, nanometer-thick polymer dielectric film with exceptional thermal/chemical resistance through a initiated chemical vapor deposition (iCVD) process. The professor Son et al. applied the vacuum-deposited stretchable polymer film to intrinsically stretchable transistors and various logic gates in the 4-inch wafer scale. (Figure 1). Recently, various approaches for adopting soft materials have been developed for intrinsically stretchable electronics which does not need any specific structural designs owing to their deformability. However, such devices employed solution-processed dielectric materials and thereby encounter critical challenges in achieving high electrical performances. Specifically, solution-processed dielectric materials exhibit micrometer-scale thicknesses, low insulating performances, chemical instability, low uniformity, and incompatibility with conventional microfabrication processes. Such features result in low gate controllability, high operation voltages, and limited scalability to large-scale circuits. In this regard, the development of an ultrathin, stretchable, and high-performance dielectric material has remained a predominant goal in the field of intrinsically stretchable electronics. ▲Figure 1. A vacuum-deposited nanoscale ultrathin polymer dielectric for large-area stretchable electronics In the current study, we present a new approach to the design of dielectric materials to resolve the aforementioned challenges in intrinsically stretchable electronic devices. Our large-scale vacuum-deposited stretchable dielectric enables the scalable fabrication of intrinsically stretchable devices with electrical performances comparable to those fabricated using the non-stretchable inorganic and stretchable organic dielectric materials (e.g., Al2O3 deposited via atomic layer deposition & spin-coated viscoelastic layer). Such high performance allows for the fabrication of intrinsically stretchable transistors and logic circuits that operate with the lowest reported power consumption. We consider that the observations of our study would transform the conventional paradigm of soft electronics. To realize the vacuum-deposited polymer dielectric, its fabrication started with copolymerizing two different monomers, isononyl acrylate (INA) and 1,3,5-trimethyl-1,3,5-tryvinyl cyclotrisiloxane (V3D3) through an initiated chemical vapor deposition (iCVD). The INA acts as a soft segment that provides stretchability and V3D3 serves as a cross-linkable hard segment, giving the polymer film robust insulating properties. The mixing ratio of the monomers (INA and V3D3) was optimized to achieve both insulating and stretching performance of the device. In this study, the world’s 1st vacuum-deposited polymer film with both elasticity and insulation properties even at a ultra-thin thickness of approximately 100 nanometers enabled by optimal combination of soft monomer and crosslinker was developed (Figure 2). ▲Figure 2. A vacuum-deposited nanoscale ultra-thin stretchable polymer dielectric film with large-area uniformity, thermal/chemical stability enabled by copolymerization in iCVD process The joint team demonstrated the wafer-scale fabrication/integration process using iCVD film. As-fabricated stretchable transistors consisting of a network-structured semiconducting carbon nanotubes (CNTs), microcrack-based stretchable metal electrodes (e.g. gate, source, and drain) featured field-effect mobility of 14.05 cm2/Vs at 10 μm channel length, subthreshold swing (SS) of 265 mV/dec, threshold voltage (Vth) of 2.47 V, and log (Ion/Ioff) of 4.63 while showing operational uniformity and stretching stability. ▲Figure 3. Wafer-scale integration of stretchable electronics using an iCVD polymer dielectric The iCVD stretchable dielectric broke the existing technical barrier of conventional organic dielectric that could not combine stable insulating performance and stretchability with submicron thickness, achieving the highest output drive current in the same channel area, which was enabled by nanoscale ultra-thin thickness-derived high capacitance and low-voltage operational property (Fig. 4). Professor Donghee Son said "We think achieving the energy-efficient performance of the stretchable electronic devices is the most important issue in the long-term reliable wearables. In this regard, we innovatively overcame the limitation of conventional flexible organic dielectric materials, which were major bottlenecks in the field of stretchable electronics technology, by demonstrating large-area integration of low-power stretchable electronic devices using vacuum-deposited nanoscale-thick ultra-thin polymer dielectric with thermal/chemical stability." SKKU-SNU-KAIST joint research team published on the paper on Feburary 3rd(Fri) on the electronic engineering department of international journal called (Nature Electronics, IF: 33.255, JCR 0.18%) This study was allowed with the support from Ministry of Science and ICT-Directorate for Basic Research in Science & Engineering, Institute for Basic Science(IBS-R006-A1 and IBS-R015-D1), National Research Foundation of Korea Basic Research in Science & Engineering(2021R1I1A1A01060389), Samsung Science & Technology Foundation(SRFC-IT2102-04). ※ Title: A vacuum-deposited polymer dielectric for wafer-scale stretchable electronics ※ DOI: https://doi.org/10.1038/s41928-023-00918-y

  • Development of a highly transparent and multifunctional wearable nanogenerator

    SKKU Advanced Institute of Nano Technology AN, SEONGPIL Prof. ·SAINT faculty Seongpil An and Il Jeon co-research team

    Development of a highly transparent and multifunctional wearable nanogenerator

    Piezoelectric nanogenerators (PENGs) that harvest electrical energy from ubiquitous mechanical motions have recently attracted significant attention as a environmentally friendly next-generation energy harvesting technology that does not rely on fossil fuels. Unlike previous research, the PENG developed this time includes excellent transparency and mechanical durability, expected to be widely applicable in various industries. In particular, since the PENG that produces electrical energy through body motions can be used as a self-powered high-sensitivity motion detecting sensor, which is expected to be used in the field of next-generation healthcare wearable electronic devices. Profs. Seongpil An and Il Jeon’s co-research team from SKKU Advanced Institute of Nanotechnology (SAINT) announced that they have developed a multifunctional transparent composite that can harvest energy, composed of piezoelectric polymer nanofibers and high-purity carbon nanotubes (CNTs) as the core materials. In previous studies, silver nanowires or electrically conductive polymers, such as PEDOT:PSS, were used as electrodes for transparent PENGs. However, metal-based transparent PENGs have inherent issues of opacity due to their natural light reflection and scattering, while electrically conductive polymer-based PENGs have shown material limitations in mechanical properties with insufficient electrical conductivity. The co-research team developed a multifunctional transparent composite capable of harvesting energy using a silicon-based elastomer embedded with piezoelectric polymer nanofibers and high-purity CNTs. The team developed piezoelectric P(VDF-TrFE) nanofibers with a diameter of 500 nm, 200 times thinner than a human hair, using the electrospinning technique and embedded them in a transparent sisilicon-basedlastomer PDMS. They also used a differentiated aerosol-assisted chemical vapor deposition (CVD) method to produce transparent CNT films for their use as electrodes in the development of a transparent PENG. The electrospinning and aerosol CVD methods used in this study are not only simple to use but also easily scalable to larger production scales compared to other methods. Based on these excellent process advantages, it is expected to have a positive impact on the commercialization of related technologies in the future. In particular, in this study, the conductivity of the CNT electrode could be improved by 3.1 times through a simple chemical doping method. The developed high-transparency PENG demonstrated decent energy harvesting performance that generated a voltage of 10 V or more even with relatively weak external force (F = 10 N). Additionally, it showed high energy harvesting performance under repetitive external force conditions of over 50,000 cycles, proving excellent mechanical durability and stability. Furthermore, when the external force was applied through a body part, such as fingers, it exhibited higher energy harvesting performance of up to 26.8 V through an additional effect of triboelectricity. It is expected that the newly developed transparent PENG can be applied extensively in the rapidly growing fields of metaverse, virtual/augmented reality, as it can not only detect subtle movements of the human body in real time by attaching it to various parts of the body, but also generate voltage signals sensitively in response to changing external forces. Prof. An said, “At SAINT, young professors who are actively engaged in research activities have formed a close relationship of solidarity, and joint research is being carried out in various directions. This research achievement is one of the results of such collaborative efforts, and it is expected to lead to more innovative research outcomes in the future.” In addition, Prof. Jeon said that “This joint research was an impressive opportunity for two research groups with different strengths to integrate their expertise into a new research field. Prof An's research team could understand [CNT-based transparent conductive electrodes] while my team could work on [PENG devices], which opened up a new avenue for expanding our research areas.” The lead author of the study, doctoral student Kiyong Kim said, “There is infinite potential for improving the energy harvesting performance of PENGs, and research should be conducted from various perspectives in the future.” The co-first author doctoral student Sangsu Lee added, “This study is the first report on the use of CNTs as electrodes in a nanogenerator, and we hope it will provide a new direction for research on transparent nanogenerators.” This study was supported by the Basic Science Research Program (2021R1F1A1061404) and the New Faculty Research Fund (2021R1C1C1009200) through the National Research Foundation of Korea (NRF). This study was published on January 18th in Advanced Functional Materials (IF: 19.924), a world-renowned academic journal in the top 5% of the material science field, based on the results that won the SKKU Graduate Student Paper Award. The lead authors of this paper are beginner in doctoral course, so their future research activities are highly anticipated. ※ Title: Highly Transparent and Mechanically Robust Energy-harvestable Piezocomposite with Embedded 1D P(VDF-TrFE) Nanofibers and Single-walled Carbon Nanotubes (Journal Advanced Functional Materials, https://onlinelibrary.wiley.com/doi/10.1002/adfm.202213374) ▲Transparent PENG developed and its fabrication process ▲ Results of energy harvesting and sensing performances

  • Employment of photosynthetic bacterium for hypoxia prevention and efficient myogenesis in muscle tissue regeneration

    Bio-Mechatronic Engineering KIM, GEUNHYUNG Prof. ·Dr. Hyeongjin Lee, Mr. Hanjun Hwangbo

    Employment of photosynthetic bacterium for hypoxia prevention and efficient myogenesis in muscle tissue regeneration

    Inadequate oxygen delivery to the macroscale 3D cell-constructs of regenerating skeletal muscle tissue has remained a multiplex issue owing to the pivotal factors such as cell metabolism and several regulatory intercellular pathways that eventually influence various cellular activities and determines cell phenotype. In addition, continuous metabolic activities of cells in 3D bioconstructs could evoke accumulation of reactive oxygen species (ROS) and induce cellular damage via oxidative stresses. To overcome this issue, the research team led by professor Geun Hyung Kim in Biomechatronic engineering department has developed oxygen-generating cyanobacteria-laden bioink and utilized in situ E-field assisted bioprinting system to rescue the cells in 3D printed constructs from hypoxic conditions for regenerating skeletal muscle tissue. Various factors such as cyanobacteria concentrations, LED light exposure and E-field were considered to optimize the developed system. As result, owing to the synergistic effects of the bioactive microenvironment that rescues cells from hypoxic conditions and activations of voltage-gated ion channels, highly aligned, multi-nucleated myofibers are obtained as well as significant upregulation (7–10-fold) of myogenic-related genes compared with conventionally prepared cell-constructs. Prof Kim states, "Based on these promising results, the combined effects of oxygen-generating cyanobacteria as a bioactive constituent of the bioink and simultaneous E-field-supporting bioprinting can offer an effective treatment strategy against severe skeletal muscle defects." To add, he states, “unlimited to muscle tissues, it can also be used as an effective artificial organ production system for various tissue regeneration which requires oxygen supply.” The described study was published in Advanced Functional Materials (IF = 19.924) in December of 2022 under support from the National Research Foundation of Korea (NRF) funded by the Ministry of Science and ICT for Bioinspired Innovation Technology Development Project (NRF-2018M3C1B7021997) and grant from the Ministry of Trade, Industry & Energy (MOTIE, Korea) under Industrial Technology Innovation Program (20009652, Technology on commercialization and materials of Bioabsorbable Hydroxyapatite less than 1 micrometer in size). ※Paper: Photosynthetic Cyanobacteria can Clearly Induce Efficient Muscle Tissue Regeneration of Bioprinted Cell-Constructs (https://doi.org/10.1002/adfm.202209157). Figure 1. Schematic diagrams of printing process and biological response of cells to in situ E-field stimulation and oxygen-generating cyanobacteria.

  • Overcoming the limitations of antitumor immunotherapy by developing K-nanoadjuvant

    SKKU Advanced Institute of Nano Technology LIM, YONGTAIK Prof. ·Seung Mo Jin, Yeon Jeong Yoo

    Overcoming the limitations of antitumor immunotherapy by developing K-nanoadjuvant

    Prof. Yong Taik Lim’s research team (SAINT) developed the world’s first kinetically activating nanoadjuvant (K-nanoadjuvant), which enables therapeutic immune cells to generate effective antitumor immunity without exhaustion. The research results were published in Nature Nanotechnology (IF: 39.213), a world-renowned academic journal in the field of multidisciplinary science. Various drugs capable of effective innate immune induction, such as toll-like receptor (TLR) agonists, have been developed throughout the history of oncology. Although these drugs contribute to immune activation, they also cause immunotoxicity and exhaustion of immune cells, resulting in ineffective cancer immunotherapy overall. To address these issues, researchers designed a nanoliposome-based novel TLR7/8a (timely activating TLR7/8 agonist; t-TLR7/8a) for the first time and revealed the efficacy of K-nanoadjuvant fabricated in combination with various TLR agonists. A nanoliposome-based K-nanoadjuvant is a novel immune function-modulating platform that not only maximizes immune cell activation but also overcomes immune cell exhaustion induced by excessive immune responses. Such effect was achieved by coordinating optimized time, order, and combinatorial code of two different immunostimulants with different mechanisms of action which induce different signal transduction routes. K-nanoadjuvant solves the problem of current immunostimulants and has a high potential for clinical application, as previous research has proven the safety of nanoliposome-based platforms in the human body. Researchers expect K-nanoadjuvant to be applied to immune checkpoint inhibitors unresponsive patient group, the latest anticancer therapeutic drug, and can be used as a next-generation anticancer therapeutic drug that can prevent recurrence/metastasis.

  • Discovery of Photovoltaically Top-performing Perovskite Crystal Facets

    Chemical Engineering PARK, NAM-GYU Prof.

    Discovery of Photovoltaically Top-performing Perovskite Crystal Facets

    Prof. Nam-Gyu Park (Department of Chemical Engineering) and his coworkers Dr. Chunqing Ma, Prof. Seok Jun Kwon, and Prof. Cheol-Woong Yang discovered photovoltaically top-performing perovskite crystal facets. Presently, the non-uniformly crystallization of the perovskite thin film is still a major constraint for high-performance and stable perovskite devices, resulting in high defect density, complex surface morphology, and so forth. More importantly, the rough morphology of perovskite thin film hinders the study of the facet properties, which is considered a crucial factor for interface property and device performance. Therefore, the effective preparation of perovskite thin films containing single crystals with well-defined facets is extremely urgent for the enhancement of perovskite device performances and the understanding of the facet properties. The achieved perovskite single crystal-assembled thin film in this work can significantly reduce the defect density induced by the non-uniformly crystallization, leading to a stable perovskite solar cell with a PCE of 24.64%. The well-defined facets on the thin film also provide a platform for the study of facet heterogeneity, which directly proves the photovoltaically top-performing (100) and (111) facets. Discovering the top-performing facets of perovskite crystals holds the secret to highly efficient perovskite solar cells (PSCs). Yet, the dominant facet properties of perovskite (i.e. (100), (110), (111) facets) remain elusive because perovskite grains typically exhibit randomly oriented domains and buried facets. Here, we demonstrate that exquisite control of the perovskite film formation enables perovskite polyhedral single crystals with well-defined facets and thereby provides a platform for the subsequent study of facet heterogeneity. Three dominated facets of (100), (111), and (110) on the perovskite film are studied experimentally and theoretically. It is found that facets with variant densities and symmetries of atoms govern the perovskite surface chemical and electronic environment and generate significant effects on the carrier dynamic, optoelectronic properties, as well as photovoltaic performance. Carrier mobility and photocurrent of the (100) crystal facet are almost comparable to those of the (111) facets, which is much higher than those of the (110) one. With the perovskite single crystal assembled thin film, the PSC achieves a quasi-steady-state (QSS) efficiency of 24.64% with improved stability to light. Our work not only suggests a strategy for designing single crystals assembled perovskite film, but also provides a deep understanding of the optoelectronic properties of halide perovskite facets. [Figure] (Top) Schematic cubic crystal structure and SEM images showing crystal facets. (Bottom) Photocurrent depending on crystal facets and stability of perovskite solar cell depending on crystal facets of the perovskite films ※ Paper Title : Photovoltaically top-performing perovskite crystal facets

  • Children Exposed to Lead may Experience Symptoms of Dementia Sooner

    Sociology LEE, HAENA Prof.

    Children Exposed to Lead may Experience Symptoms of Dementia Sooner

    Prof. Haena Lee and colleagues published a study in Science Advances (IF: 14.14) on the long-term impact of childhood lead exposure on cognitive functioning in later life. The study, one of the first to investigate the decades-long consequences of lead poisoning, suggests countries could face an explosion of people seeking support for dementia as individuals who were exposed to high lead levels during early life progress into old age. Although scientists have long known that children and adults who are exposed to lead have poorer cognitive and educational outcomes, few studies have investigated the longer-term consequences. Lee and her colleagues combined data from the US-based longitudinal Health and Retirement Study (HRS), which has followed the cognitive health of thousands of adults over several decades, with census records to pinpoint where 1,089 of these individuals lived as children. They also mapped the locations of towns and cities that used lead pipes and had acidic or alkaline water – a proxy for lead exposure. The research revealed that people who lived in cities with lead-contaminated water as children had worse baseline cognitive functioning – a measure of their ability to learn, process information, and reason – at age 72, compared with those who did not. The difference was equivalent to being roughly eight years older. Although childhood lead exposure doesn’t necessarily mean a person is at greater risk of dementia, the authors suggest that they may experience cognitive impairment earlier as they start out at a substantially lower point. The team found no difference in the rate of cognitive decline between the two groups – possibly because their cognitive function was tested after any brain damage due to lead exposure had taken place. Prof. Lee said, “More research is clearly and urgently needed to better understand the lifelong implications of childhood lead exposure for brain aging and to identify effective interventions to mitigate lead’s long-term consequences.” This research has collaborated with Prof. John Robert Warren (Sociology, University of Minnesota), Dr. Mark Lee (Minnesota Population Center, University of Minnesota), and Prof. Joseph Ferrie (Economics, Northwestern University). The Guardian article on this research can be found here: https://www.theguardian.com/society/2022/nov/09/children-exposed-to-lead-may-experience-symptoms-of-dementia-sooner-study Please visit the website for more information. DOI: 10.1126/sciadv.abn5164

  • Using Natural Language Processing Algorithms ▼ to Track Emotions From 30 Years of K-Pop Hits

    Psychology KIM, MINUE Prof.

    Using Natural Language Processing Algorithms to Track Emotions From 30 Years of K-Pop Hits

    Prof. Minue Kim (Department of Psychology) collaborated with Prof. Wonkwang Jo (Graduate School of Public Health, Seoul National University) on a research project entitled, Tracking emotions from song lyrics: analyzing 30 years of K-pop hits. Emotions that are shared by a large number of people are known to broadly impact affective experiences at the individual level. Music, especially hit songs that have garnered popularity in a society, can be usefully viewed as being reflective of the emotional preferences and experiences of its members. As such, analyzing the musical features of K-pop songs that emerged as hits over time may offer a useful strategy for understanding the emotional characteristics of Koreans at the sociocultural level. K-pop has risen in popularity in the mainstream music scene and is enjoying a more global reach than before, and thus the emotions expressed in K-pop have implications beyond Korea. Using text mining and natural language processing algorithms on 30 years of K-pop hit songs, we sought to answer the following research questions: What are the emotions observed in K-pop lyrics, and how do they change over time? Specifically, using morpheme frequency analysis and structural topic modeling on song lyrics, we sought to investigate the changes in the appearance of words and topics conveying positive and negative emotions. In this work, we used lyrics from songs on Melon’s top 100 list for each year from 1990 to 2019 as our data. Both morpheme frequency analysis and STM yielded converging results: The proportion of adjectives and topics that express positive emotions showed an increasing trend in the past 30 years. Conversely, the proportion of topics that convey negative emotions showed a decreasing trend during the same time period. Surprisingly, this temporal shift is the exact opposite of what prior research has found from popular songs in the United States. These seemingly conflicting observations may be reconciled by considering cultural differences: that the United States boasts a highly individualistic culture, whereas Korea is a traditionally collectivistic culture. For instance, in an already individualistic culture like the United States, further increases in individualistic traits may exacerbate the adverse aspects of individualism (e.g., a rise in narcissistic traits). On the other hand, beneficial features of individualism emerge as individualistic traits increase, at least initially, in a collectivistic culture such as Korea. Individualistic values being introduced to a collectivistic society could encourage people to pursue their individual goals and life course, while distancing themselves against the potentially excessive obligation to the community. We also argue that economic growth (e.g., rise in individual purchasing power and gross domestic product) may also have served as the background for increasing feelings of and/or preference for positive emotions. More generally, our study illustrates a strategy for tracking emotions that people value and prefer from large natural language data, supplementing existing methods such as self-reported surveys and laboratory experiments. This work is published at ‘Emotion’ (https://doi.org/10.1037/emo0001185). *Tracking emotions from song lyrics: Analyzing 30 years of K-pop hits (Journal: Emotion, DOI: 10.1037/emo0001185)

  • Green Hydrogen Catalyst Material with ▼ New MXene-Ni2P Phosphide Hybrid

    Chemical Engineering LEE, JUN YOUNG Prof. ·Prof. Jung Kyu Kim, Nguyen Duong Nguyen

    Green Hydrogen Catalyst Material with New MXene-Ni2P Phosphide Hybrid

    Prof. Jun Young Lee (School of Chemical Engineering) and Prof. Jung Kyu Kim (School of Chemical Engineering) reported his collaboration research achievements with Prof. Hyeyoung Shin (Graduate School of Energy Science and Technology, Chungnam National University): Interfacial Strain-Modulated Nanospherical Ni2P by Heteronuclei-Mediated Growth on Ti3C2Tx MXene for Efficient Hydrogen Evolution. Since the global warming problem from usage of fossil fuel, the hydrogen fuel is getting attention due to clean and renewable properties. Among various strategies for hydrogen evolution reaction (HER), electrochemical water splitting is regarded as potential approach for zero-carbon emission process. In general, the novel metal based materials, such as Pt, Pd, Ir and Ru, have been applied for the most efficient HER catalyst. However, the scarcity of novel metal and unstability in electrolyte properties hinder to scale-up the hydrogen production process. To replace novel metals, non-novel metal based materials have been exploited as an promising candidate for HER electrocatalysts. Among them, Ni2P has been studied as hot topic because of its highly activity HER. However, it is still far from replacing noble metal based catalyst due to its poor intrinsic poor conductivity and stability. In this work, we demonstrated a hybrid catalyst with Ni2P and Ti3C2Tx (MXene), which consisting chemically anchored Ni2P on surface-defect engineered MXene. Using collodial synthesis, Ni2P species were in situ heteronuclei growth on surface defect point of MXene to syntehsize strongly coupled heterostructure. Notably, the significant tensile strain of the Ni2P lattice was found at the interface between Ni2P and MXene. The strain changed atom bond length and electronic structure of matrials, and it induced more preferable reaction mechanism for HER. Consequently, the Ni2P @MXene hybrid exhibit outstanding electrocataytic activity with 123.6 mV at 10mA cm-2 and long-term stability. We propose the hybridization between Ni2P and MXene open up a novel strategy for design efficient non-noble metal based catalyst. This research achievement was selected as the cover art of journal ‘Small’ (DOI: https://doi.org/10.1002/smll.202204797) *Interfacial Strain-Modulated Nanospherical Ni2P by Heteronuclei-Mediated Growth on Ti3C2Tx Mxene for Efficient Hydrogen Evolution (저널: Small, DOI: 10.1002/smll.202204797) ▲ A depiction of the growth of heterogeneous nuclei of 0-dimensional spherical nickel phosphide on the surface of a 2-dimensional plate-shaped MXene material. Strain occurs at the hybrid material interface to secure excellent green hydrogen production performance. ▲Cover art of journal 'Small'

  • A Novel Mechanism for the Regulation of Lung Cancer Progression by Cereblon (CRBN)

    Medicine LEE, KI YOUNG Prof. ·Mi Jung Kim, Ji Soo Lee, Ji Young Kim

    A Novel Mechanism for the Regulation of Lung Cancer Progression by Cereblon (CRBN)

    Cereblon (CRBN) has been identified as a primary target of immunomodulatory drugs in multiple myeloma. Herein, for the first time, we demonstrate that CRBN expression is functionally involved in lung cancer progression through the regulation of autophagy by toll‐like receptor (TLR)2, TLR4 and TLR7. TLR signalling is associated with the induction of autophagy and plays a pivotal role in the progression and pathogenesis of lung cancer. The onset and development of lung cancer are regulated by a variety of external and internal factors that influence the tumor microenvironment (TME). The downregulation or upregulation of genes in lung cancer cells is highly likely to be implicated in the pathogenesis and progression of lung cancer. In this study, we show that CRBN is downregulated in lung cancer cells and associated with lung cancer progression. Notably, we found that CRBN inhibits the BECN1 ubiquitination to induce autophagy and attenuates the production of IL‐6, CCL2, CCL20 and MMP2 cytokines in response to TLR stimulations in healthy lung cells expressing CRBN (Figure 1). In lung cancer cells with downregulated CRBN (Figure 1), engagements of TLRs enhance autophagy induction through the increases of BECN1 ubiquitination and the production of IL‐6, CCL2, CCL20 and MMP2 cytokines, eventually facilitating lung cancer progression. Taken together, our clinically comparative results and functional investigations of CRBN in lung cancer progression will potentially contribute to translational approaches for lung cancer intervention. Additionally, CRBN can be a potent prognostic marker for lung cancer and provides important implications in clinical and translational lung cancer biology. Article: Kim MJ, Lee JS, Kim JY, Choi B, Son J, Min Y, Jeong SK, Kim DH, Lee JS, Chun E, Lee KY. CRBN is downregulated in lung cancer and negatively regulates TLR2, 4 and 7 stimulation in lung cancer cells. Clinical and translational medicine (IF: 11.492). 2022 Sep;12(9):e1050.

  • World's first development of ultrahigh temporal resolution brain neuronal activity imaging technology that can see...

    Biomedical Engineering PARK, JANGYEON Prof.

    World's first development of ultrahigh temporal resolution brain neuronal activity imaging technology that can see...

    World's first development of ultrahigh temporal resolution brain neuronal activity imaging technology that can see the flow of thoughts The research team led by Professor Jang-Yeon Park of the Department of Biomedical Engineering at Sungkyunkwan University has developed the world’s first next-generation brain function imaging technology that can directly image brain neuronal activity in vivo with ultra-high resolution of a few milliseconds. The main verification of the proposed brain neuronal activity imaging technology was carried out in collaboration with the research team of Professor Jeehyeon Kwag of Korea University (currently Seoul National University), an electrophysiology research group. Non-invasive brain function imaging (or neuroimaging) techniques play an important role in elucidating how the brain functions in vivo. However, the most widely used non-invasive brain functional imaging techniques, such as electroencephalogram(EEG), magnetoencephalogram(MEG), and functional magnetic resonance imaging(fMRI), have distinct advantages and disadvantages in terms of temporal and spatial resolution, acting as important limitations for in vivo brain research. For example, EEG and MEG give low spatial resolution (~centimeters, cm) despite high temporal resolution (~milliseconds, ms), and functional magnetic resonance imaging (fMRI) provides low temporal resolution (~seconds, sec) despite high spatial resolution (~millimeters, mm), providing only indirect neural activity information based on blood flow. Prof. Park’s research team predicted that direct imaging of neural activity (DIANA) would be possible if magnetic resonance imaging (MRI) with a temporal resolution of several milliseconds, which is comparable to the time scale of neural action potentials, was implemented. The research team realized ultra-high time resolution in milliseconds using a method of segmenting image data. Using this, the neural activity directly transmitted in the brain neural network could also be imaged. In addition, the research team proposed an important biophysical hypothesis for possible signal sources of DIANA. Prof. Par’s research team verified the proposed brain neuronal activity imaging technique using an in vivo mouse brain in a 9.4T animal MRI system. By applying repetitive electrical stimulation to the mouse whiskers, time series images of DIANA in neural networks including the thalamus and primary somatosensory cortex (S1) were acquired with s spatial resolution of 0.22 mm and a temporal resolution of 5 ms. As a result, DIANA responses in S1 were confirmed at 20-25 ms and at 10-15 ms in the thalamus, which successfully imaged how neuronal activity propagates in the thalamus-cortical pathway. In addition, the research team proposed a change in T2 relaxation time due to changes in membrane potential and cell volume accompanying neural activity as a new contrast mechanism for DIANA. The novel brain function imaging technique proposed by Prof. Park’s research team can show how neural activity is transmitted in the brain neural network in vivo, along with direct imaging of neural activity, by imaging brain neural activity with a time resolution of a few milliseconds. Through this next-generation brain function imaging technology, it is expected to implement a dynamic brain neural network model close to reality that can reflect and express how brain functions are actually performed in various cognitive processes. From a clinical point of view, it is also expected to contribute greatly to individual precision diagnosis, the trend of modern medicine, by enabling objective and quantitative evaluation of cognitive impairments in neurodegenerative diseases such as Alzheimer’s disease and Parkinson’s disease, as well as mental disorders including depression and neurodevelopmental disorders. Professor Park said, “This study is very meaningful in that it realized an in vivo brain neural activity imaging with both high temporal and high spatial resolution, which has been a long-cherished dream in the field of brain function imaging.”, and also said, “In particular, being able to image neural activity and its propagation in high spatiotemporal resolution in the neural network means that the flow of information, that is, the flow of thoughts, can be seen in the cognitive process in the brain neural network. Through this, it is expected that an in-depth understanding of the ‘thinking brain’ will be possible by elucidating the hierarchical connectivity of brain functions.” He finally added, “If it is proven that DIANA can also be applied to humans, it could be a game changer in the field of brain science.” The results of this study were published as a Research Article on October 14, 2022 in ‘Science’ (IF: 47.728), along with Perspectives, a commentary article published together with noteworthy papers. Also, along with the publication of the paper, Nature news covered an article on this paper. In addition, The Scientist(UK), STAT news(USA), and ChosunBiz(Korea) also published articles about this paper. ※ Paper Title: “In vivo direct imaging of neuronal activity at high temporo-spatial resolution” ※ Science, https://www.science.org/doi/10.1126/science.abh4340 [Fig. 1] High temporo-spatial resolution DIANA captures thalamocortical spike propagation. (A) Illustration of the DIANA experiment to image contralateral S1BF and thalamus applying electrical stimulation to left whisker pad in an anesthetized mouse on a 9.4 T scanner (right) and brain imaging of a coronal slice containing both thalamus and S1BF regions (left). (B) BOLD activation map obtained as a reference (n = 10 mice). (C to E) Time series of t-value maps of DIANA for 30 ms after whisker-pad stimulation in 5 ms temporal resolution from 5 mice (C), percent changes in DIANA signals (D), and bar graphs showing the mean latencies of peak DIANA responses from the thalamus (green) and contralateral S1BF (magenta) (E) (n = 10 mice, ****: p < 0.0001, paired t­-test). (F) Top: Illustration of electrophysiological recording in mice in vivo with silicon probes implanted in the thalamus and the contralateral S1BF applying electrical whisker-pad stimulation, Bottom: Electrode track marking using a fluorescent lipophilic dye (DiI). (G and H) Multi-unit activity (MUA) (black trace, top) from which single-unit spikes (bottom) were analyzed in the thalamus (green) (G) and the contralateral S1BF (magenta) (H). (I) Post-stimulus time histogram (PSTH) of the whisker-pad stimulation-responsive single units over time in the thalamus (top) and contralateral S1BF (bottom) with DIANA signals superimposed for comparison. (J) Bar graph showing the latencies of peak spike firing rates of whisker-pad stimulation-responsive single units recorded from the thalamus (light green, n = 23 units from 10 mice) and contralateral S1BF (light magenta, n = 23 units from 5 mice). Vertical dotted lines indicate the whisker-pad stimulation on a set time (red) (D, and G to I) and latency of peak spike firing rate (thalamus, green; contralatera lS1BF, magenta) (I). (****:p < 0.0001, unpaired t­-test). All data are mean ± SEM. [Fig. 2] Sublayer-specific DIANA responses revealed functionally distinct sublayer-specific microcircuits. (A and B) Illustration of DIANAexperiment (A) and in vivo spike recording (B) in VPMd, VPMv, POm, S1BF, and S2 in response to electrical whisker-pad stimulation. Yellow dotted boxes in (A, right) indicate extraction areas of DIANA heatmaps. (C) Heatmap (left) and temporal profile (middle) for percent change in DIANA signal, displayed with a mean latency of peak DIANA response from VPMd (dark green), VPMv (green), and POm (lightgreen) (right) (n = 9 mice). (D) Heatmap of in vivo-recorded single-unit spike firing rate normalized to the peak firing rate (left) and temporal profile of spike firing rate (middle), displayed with a mean latency of peak spike firing rate in VPMd (darkgreen, n = 22 units from 16 mice), VPMv (green, n = 15 units from 16 mice), and POm (lightgreen, n = 59 units from 14 mice) (right). (E and F) Same as (C) and (D) but for DIANA experiments (n = 9 mice) and spikes recorded from S1BF in L2/3 (light pink, n = 9 units from 28 mice), L4 (pink, n = 51 units from 28 mice), L5 (magenta, n = 60 units from 28 mice), and L6 (dark magenta, n = 18 units from 28 mice). (G and H) Same as (C) and (D) but for DIANA experiments (n = 9 mice) and spikes recorded from S2 in L2/3 (light orange, n = 6 units from 20 mice), L4 (orange,n = 27 units from 20 mice), L5 (brown, n = 35 units from 20 mice), and L6 (dark brown, n = 14 units from 20 mice). The base in DIANA heatmaps indicates the average of pre-stimulation frames. The asterisk in the middle of (C) and (E) indicates the statistically significant negative signal. All data are mean ± SEM. *: p < 0.05, **: p < 0.01, ****: p < 0.0001, n.s.: p > 0.05 for paired, unpaired, and Welch t­-test. * News Link Nature https://www.nature.com/articles/d41586-022-03276-5 TheScientist https://www.the-scientist.com/news-opinion/new-mri-technique-tracks-brain-activity-at-millisecond-timescales-70626 STAT news https://www.statnews.com/2022/10/13/faster-brain-imaging-seems-to-overcome-limitations-of-mri-scans/ Wangyi Newspaper https://c.m.163.com/news/a/HJUQ2AP905349C3F.html?spss=newsapp&spsnuid=oZlx0DZd33OSWgG0kMOOUuM7BDC%2FiTfKiWqAqYquhrd6bSMjx5AhlFPCxNgjPPppLKLFB1b60t5bfMyo%2BfU9vA%3D%3D&spsdevid=01FAE289-ED08-4A0C-8400-E606EBBCD204&spsvid=&spsshare=wx&spsts=1666052754167&spstoken=SfdkYiZhpyVZWhpU%2BRUwim4QV5mcCcJr7ezvwp%2Fwwy%2FIAvHE%2BhK9eCCy270blp2R&spssid=2abc334fb2d6ee470fa4c0642a06a8a8&spsw=2&isFromH5Share=article

  • Establishment of MEMS and Sensor Research Platform

    Advanced Materials Science and Engineering SUH, SUJEONG Prof.

    Establishment of MEMS and Sensor Research Platform

    Sungkyunkwan University's Material & Process Platform Center for Convergence Sensor (Director, Prof. Su-Jeong Suh), supported by the Gyeonggi Regional Research Center (GRRC) project, developed advanced materials and process technologies necessary to secure the original technology with 7 professors and 10 companies. Also, conducting industry-academic research to become a technological and industrial base that leads the global sensor industry by developing Master's and doctorate personnel in the field. Prof. Suh, While working as a professor in the school of Materials Science and Engineering for 33 years, not only academic achievement but also carried out large-scale government support projects based on materials and processes such as Technology Innovation Center (TIC), Regional Research Center (RRC), Regional Innovation system (RIS), Regional Innovation Center (RIC) supported by Ministry of Trade, Industry and Energy, Ministry of Science and ICT, Ministry of Education, Ministry of SMEs and Startups, and Gyeonggi Province. Through these research funds, research equipment infrastructure such as clean rooms and ultra-precision analysis equipment was established. Recently, Prof. Suh established a semiconductor process (cleaning, oxidation, photolithography, etching, sputter, CMP, bonder, etc.) facility for 8-inch wafer processing in the FAB. Through this expansion of the research base, various government projects (technology development projects for Materials ‧ Components ‧ Equipment, core research support center, and University Innovation Center (UIC)) are attracted and carried out with many excellent faculty members. In addition, the center has a performance of infrastructure expansion and technical support for 520 external companies. Prof. Suh, over the past five years, has achieved the application and registration of 29 domestic and oversea patents and 12 technology transfers, including patent transfers to U.S. companies. And he attracted a "field human power development project" using semiconductor infrastructure, and conducted sensor and semiconductor classes producing 314 workers and 522 unemployed workers. In addition, 730 workers and 290 unemployed workers will be trained by 2027. The appointment of Prof. Suh as the distinguished professor is expected to accelerate industry-university cooperation by activating the center's established equipment and a cooperative system with industry.

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