Sung Sik Lee

Last Name

Lee

First Name

Sung Sik

ORCID

0000-0001-9267-232X

Organisational unit

02891 - ScopeM / ScopeM

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Publications 1 - 10 of 56

Guidelines for the use and interpretation of assays for monitoring autophagy (3rd edition)
Klionsky, Daniel J.; Abdelmohsen, Kotb; Abe, Akihisa; et al. (2016)
Autophagy
High-mobility transport in isotopically enriched ¹²C and ¹³C exfoliated graphene
Iwakiri, Shuichi; Miller, Jakob; Lang, Florian; et al. (2023)
Physical Review Research
Graphene quantum dots are promising candidates for qubits due to weak spin-orbit and hyperfine interactions. The hyperfine interaction, controllable via isotopic purification, could be the key to further improving the coherence. Here, we use isotopically enriched graphite crystals of both ¹²C and ¹³C grown by a high-pressure-high-temperature method to exfoliate graphene layers. We fabricated Hall bar devices and performed quantum transport measurements, revealing mobilities exceeding 10⁵ cm² /V s and a long mean free path of microns, which are as high as natural graphene. Shubnikov–de Haas oscillations, quantum Hall effect up to the filling factor of one, and Brown-Zak oscillations due to the alignment of hBN and graphene are observed thanks to the high mobility. These results constitute a material platform for physics and engineering of isotopically enriched graphene qubits.
Lateral migration and focusing of colloidal particles and DNA molecules under viscoelastic flow
Kim, Jae Young; Ahn, Sung Won; Lee, Sung Sik; et al. (2012)
Lab on a Chip
Cell Stretching Measurement Utilizing Viscoelastic Particle Focusing
Cha, Sukgyun; Shin, Taeho; Lee, Sung Sik; et al. (2012)
Analytical Chemistry
Confinement effect on lateral particle migration in deoxyribonucleic acid solution
Jung, Yoonyoung; Jin, Daekwon; Shim, Tae Soup; et al. (2023)
Physics of Fluids
Lateral migration and focusing of particles in viscoelastic fluids have recently been widely exploited in various microfluidic applications, such as particle counting and separation. However, there are still many unresolved problems regarding the underlying mechanisms that induce lateral migration in polymer solutions. In particular, as the sizes of particles and polymers (e.g., radius of gyration) become comparable, continuum mechanics (constitutive modeling)-based analyses are expected to fail, which has not yet been investigated. If lateral particle migration occurs only due to conventional bulk viscoelastic effects, the equilibrium particle positions are expected to remain constant when the aspect ratio ( r p c ) of the particle to channel dimensions is nearly fixed. In this study, we found that as the channel dimension of the cross section decreases, a transition occurs in which individual polymers ( λ -deoxyribonucleic acid) behave as deformable particles, and consequently, the equilibrium positions change. This study contributes to clarifying the lateral particle migration in polymer solutions and can be applied to various applications, such as deformability-selective particle separation.
Crosstalk and spatiotemporal regulation between stress-induced MAP kinase pathways and pheromone signaling in budding yeast
van Drogen, Frank; Dard, Nicolas; Pelet, Serge; et al. (2020)
Cell Cycle
Budding yeast, Saccharomyces cerevisiae, has been widely used as a model system to study cellular signaling in response to internal and external cues. Yeast was among the first organisms in which the architecture, feedback mechanisms and physiological responses of various MAP kinase signaling cascades were studied in detail. Although these MAP kinase pathways are activated by different signals and elicit diverse cellular responses, such as adaptation to stress and mating, they function as an interconnected signaling network, as they influence each other and, in some cases, even share components. Indeed, various stress signaling pathways interfere with pheromone signaling that triggers a distinct cellular differentiation program. However, the molecular mechanisms responsible for this crosstalk are still poorly understood. Here, we review the general topology of the yeast MAP kinase signaling network and highlight recent and new data revealing how conflicting intrinsic and extrinsic signals are interpreted to orchestrate appropriate cellular responses. © 2020 Informa UK Limited.
Multiwavelength Light-Responsive Au/B-TiO2 Janus Micromotors
Jang, Bumjin; Hong, Ayoung; Kang, Ha Eun; et al. (2017)
ACS Nano
Construction and use of a microfluidic dissection platform for long-term imaging of cellular processes in budding yeast
Huberts, Daphne H.E.W.; Lee, Sung Sik; Gonzalez, Javier; et al. (2013)
Nature Protocols
Simple Assessment of Red Blood Cell Deformability Using Blood Pressure in Capillary Channels for Effective Detection of Subpopulations in Red Blood Cells
Kang, Yang Jun; Serhrouchni, Sami; Makhro, Asya; et al. (2022)
ACS Omega
Assessment of red blood cell (RBC) deformability as a biomarker requires expensive equipment to induce and monitor deformation. In this study, we present a simple method for quantifying RBC deformability. We designed a microfluidic channel consisting of a micropillar channel and a coflowing channel connected in series. When blood (loading volume = 100 mu L) was injected continuously into the device under constant pressure (1 bar), we monitored the boundary position of the blood and the reference flow in the coflowing channel. A decrease in the deformability of RBCs results in a growing pressure drop in the micropillar channel, which is mirrored by a decrease in blood pressure in the coflowing channel. Analysis of this temporal variation in blood pressure allowed us to define the clogging index (CI) as a new marker of RBC deformability. As a result of the analytical study and numerical simulation, we have demonstrated that the coflowing channel may serve as a pressure sensor that allows the measurement of blood pressure with accuracy. We have shown experimentally that a higher hematocrit level (i.e., more than 40%) does not have a substantial influence on CI. The CI tended to increase to a higher degree in glutaraldehyde-treated hardened RBCs. Furthermore, we were able to resolve the difference in deformability of RBCs between two different RBC density subfractions in human blood. In summary, our approach using CI provides reliable information on the deformability of RBCs, which is comparable to the readouts obtained by ektacytometry. We believe that our microfluidic device would be a useful tool for evaluating the deformability of RBCs, which does not require expensive instruments (e.g., high-speed camera) or time-consuming micro-PIV analysis.
Ingested nano- and microsized polystyrene particles surpass the intestinal barrier and accumulate in the body
Schwarzfischer, Marlene; Niechcial, Anna; Lee, Sung Sik; et al. (2022)
NanoImpact
Plastic pollution is a major global challenge of our times, baring a potential threat for the environment and the human health. The increasing abundance of nanoplastic (NP) and microplastic (MP) particles in the human diet might negatively affect human health since they - particularly in patients suffering from inflammatory bowel disease (IBD) – might surpass the intestinal barrier. To investigate whether ingested plastic particles cross the intestinal epithelium and promote bowel inflammation, mice were supplemented with NP or MP polystyrene (PS) particles for 24 or 12 weeks before inducing acute or chronic dextran sodium sulfate (DSS) colitis with continuous plastic administration. Although ingested PS particles accumulated in the small intestine and organs distant from the gastrointestinal tract, PS ingestion did not affect intestinal health nor did it promote colitis severity. Although the lack of colitis-promoting effects of small PS particles might be a relief for IBD patients, potential accumulative effects of ingested plastic particles on the gastrointestinal health cannot be excluded.

Publications 1 - 10 of 56

Sung Sik Lee

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