Kihyun Lee

Transcriptional regulatory mechanisms of lineage priming in embryonic development are largely uncharacterized because of the difficulty of isolating transient progenitor populations. Directed differentiation of human pluripotent stem cells (hPSCs) combined with gene editing provides a powerful system to define precise temporal gene requirements for progressive chromatin changes during cell fate transitions. Here, we map the dynamic chromatin landscape associated with sequential stages of pancrea

The hormone leptin plays a key role in energy homeostasis, and the absence of either leptin or its receptor (LepR) leads to severe obesity and metabolic disorders. To avoid indirect effects and to address the cell-intrinsic role of leptin signaling in the immune system, we conditionally targeted LepR in T cells. In contrast with pleiotropic immune disorders reported in obese mice with leptin or LepR deficiency, we found that LepR deficiency in CD4(+) T cells resulted in a selective defect in bot

BACKGROUND: The impact of human activities on the environmental resistome has been documented in many studies, but there remains the controversial question of whether the increased antibiotic resistance observed in anthropogenically impacted environments is just a result of contamination by resistant fecal microbes or is mediated by indigenous environmental organisms. Here, to determine exactly how anthropogenic influences shape the environmental resistome, we resolved the microbiome, resistome,

Emerging evidence indicates that NADPH oxidase (NOX) and its reactive oxygen species (ROS) products modulate a variety of cellular events, including proliferation, differentiation, and apoptosis. In this study, we investigated the functions of NOX2 and ROS in immune modulation using NOX2 knockout (KO) mice. Interestingly, NOX2 KO mice spontaneously developed arthritis with onset at 6-7 wk of age and high incidence (60%) at 15-18 wk of age. Arthritis severity in NOX2 KO mice was proportionally in

T-box-containing protein expressed in T cells (T-bet) is a master transcription factor for the development of interferon (IFN) gamma-producing T helper 1 (Th1) cells and also functions in other immune cells including natural killer (NK), cytotoxic T lymphocytes and dendritic cells. T-bet-deficient mice increased susceptibility to viral infection and tumor development due to the defective functions of immune cells. T-bet is known to play a key role in NK-mediated antimetastatic response; however,

Scanning transmission electron microscopy (STEM) is an indispensable tool for atomic-resolution structural analysis for a wide range of materials. The conventional analysis of STEM images is an extensive hands-on process, which limits efficient handling of high-throughput data. Here, we apply a fully convolutional network (FCN) for identification of important structural features of two-dimensional crystals. ResUNet, a type of FCN, is utilized in identifying sulfur vacancies and polymorph types o

In previous studies researchers have identified several antecedents of followers' taking charge from their leader, but the ethical nature of taking charge has rarely been considered. Drawing on both social exchange theory and social identity theory, I examined the influence of ethical leadership on followers taking charge through the mediation of trust in leader and identification with leader. Using data obtained from 236 petty officers and their immediate supervisors in the South Korean Navy, I

Peroxiredoxin (Prx) II is an intracellular antioxidant molecule that eliminates hydrogen peroxide, employing a high substrate-binding affinity. PrxII deficiency increases the levels of intracellular reactive oxygen species in many types of cells, which may increase reactive oxygen species-mediated inflammation. In this study, we investigated the susceptibility of PrxII knockout (KO) mice to experimentally induced colitis and the effects of PrxII on the immune system. Wild-type mice displayed pro

Whole genome and metagenome sequencing are powerful approaches that enable comprehensive cataloging and profiling of antibiotic resistance genes at scales ranging from a single clinical isolate to ecosystems. Recent studies deal with genomic and metagenomic data sets at larger scales; therefore, designing computational workflows that provide high efficiency and accuracy is becoming more important. In this review, we summarize the computational workflows used in the research field of antibiotic r

Purpose The impact of leader-member exchange (LMX) differentiation on group performance has been considered ambiguous. The purpose of this paper is to resolve this ambiguity by theorizing and examining a curvilinear relationship between LMX differentiation and group performance, and the moderating effects of group diversity on this relationship. Design/methodology/approach Data were drawn from 63 work groups (consisting of 322 members and 63 group leaders) selected from 27 technology service com

This paper provides a loss analysis and comparison of high power semiconductor devices in 5MW Permanent Magnet Synchronous Generator (PMSG) Medium Voltage (MV) Wind Turbine Systems (WTSs). High power semiconductor devices of the press-pack type IGCT, module type IGBT, press-pack type IGBT, and press-pack type IEGT of both 4.5kV and 6.5kV are considered in this paper. Benchmarking is performed based on the back-to-back type 3-level Neutral Point Clamped Voltage Source Converters (3L-NPC VSCs) sup

In order to better understand the social aspects of job crafting, this study explores the direct and interactive effects of leader–member exchange (LMX) and team-member exchange (TMX) on three types of job crafting (i.e., task, relational, and cognitive crafting). Drawing on both social exchange theory and the job demands–resources model, this study examines the social antecedents of job crafting in a sample of 336 members of three shipbuilding companies. The results indicate that individuals wh

This paper provides a comparison of high power semiconductor devices in 5MW-class Permanent Magnet Synchronous Generator (PMSG) Medium Voltage (MV) wind turbines. High power semiconductor devices of IGCT, module type IGBT, press-pack type IGBT, and press-pack type IEGT of both 4.5kV and 6.5kV are considered in this paper. Benchmarking is performed based on neutral point clamped 3-level back-to-back type voltage source converter supplied from grid voltage of 4160V. The feasible number of semicond