About

Brian Won-Sik Kim, MD, is an Associate Professor of Medicine in the Department of Medicine at The University of Chicago. His clinical practice focuses on endocrinology with a specialization in thyroid diseases, including hypothyroidism, hyperthyroidism, autoimmune thyroid disease, and structural thyroid conditions such as thyroid nodules and goiter. He has a particular focus on thyroid cancer and routinely performs thyroid ultrasounds and biopsies in his clinical work. Dr. Kim trained as an endocrinologist at Brigham and Women's Hospital, Harvard Medical School, and currently serves as the director of the clinical thyroid program at the University of Chicago. He is an active member of the American Thyroid Association, participating in numerous committees and contributing to the development of national guidelines. His research includes investigations into the effects of radioactive iodine therapy for hyperthyroidism, thyroid hormone action, and the molecular mechanisms underlying thyroid function and disease. Dr. Kim's work has contributed to the understanding of thyroid hormone economy, the clinical management of thyroid nodules and cancer, and the broader implications of thyroid disease in metabolic and hematologic contexts.

Research topics

• Biology
• Cancer research
• Materials science
• Nanotechnology
• Pharmacology
• Immunology
• Medicine
• Cell biology
• Chemistry
• Pathology

Selected publications

• Sequential Process Optimization of HfO ₂ /Al ₂ O ₃ Bilayer RRAM for Enhanced Synaptic Performance and On-Chip MNIST Learning

  ACS Applied Electronic Materials · 2026-04-01

  articleCorresponding

  HfO2/Al2O3 bilayer resistive random-access memory (RRAM) exhibits gradual resistive switching behavior, which is advantageous for achieving linear and symmetric conductance modulation required for reliable synaptic operation in neuromorphic computing. However, large device variability and poor endurance remain critical challenges that must be addressed for practical synaptic applications of RRAM. In this work, the performance of HfO2/Al2O3 bilayer RRAM was systematically improved through the sequential optimization of fabrication conditions. By combining postdeposition annealing (PDA) of the switching layer, optimization of the titanium (Ti) buffer layer thickness, and ultrathin molybdenum (Mo) deposition at the HfO2/Al2O3 interface, the optimized devices exhibited over 70% reduction in cycle-to-cycle (C2C) operational variability, excellent DC endurance (>103 cycles), a high on/off ratio (average 96.8), and robust retention (>4000 s at 85 °C). Cross-sectional transmission electron microscopy and energy-dispersive X-ray spectroscopy (EDS) analyses revealed that Mo nanoislands formed by the ultrathin Mo layer play a key role in suppressing the stochastic formation of conductive filaments. In addition, fitting of DC I–V characteristics indicated that direct tunneling, Fowler–Nordheim tunneling, and Poole–Frenkel emission are the dominant conduction mechanisms governing device operation. Finally, leveraging the obtained long-term potentiation and long-term depression characteristics, on-chip learning-based pattern recognition was evaluated using the Modified National Institute of Standards and Technology (MNIST) data set, achieving a maximum classification accuracy of 81.56%. These results demonstrate the strong potential of performance-optimized HfO2/Al2O3 bilayer RRAM as a synaptic device for neuromorphic computing applications.

  PublisherDOI

• Polystyrene Nanoplastics Induce Inflammasome Activation in Nasal Epithelial Cells via <scp>ROS</scp> ‐Mediated Mitochondrial Dysfunction

  Environmental Toxicology · 2026-04-07

  article

  Nanoplastics are emerging airborne pollutants capable of reaching the nasal cavity. However, their effects on nasal epithelial health remain poorly understood. This study investigated how polystyrene (PS) nanoplastics affect nasal epithelial cells, focusing on NOD-like receptor protein 3 (NLRP3) inflammasome activation, oxidative stress, and mitochondrial injury. Human RPMI 2650 nasal epithelial cells were exposed to PS nanoplastics at various concentrations for 24 h. Cellular responses were evaluated by assessing viability, inflammasome protein expression, reactive oxygen species (ROS) generation, mitochondrial membrane potential, and adenosine triphosphate (ATP) levels using colorimetric assays, Western blotting, and flow cytometry. Mitochondrial ROS was analyzed with MitoSOX, and mitochondrial regulators sirtuin 1 (SIRT1) and AMP-activated protein kinase (AMPK) were examined to clarify underlying mechanisms. The antioxidant N-acetylcysteine (NAC) was used to assess the role of oxidative stress. PS exposure reduced cell viability and increased the expression of inflammasome-related proteins including NLRP3, apoptosis-associated speck-like protein containing a caspase-recruitment domain (ASC), and cleaved caspase-1. Protein levels peaked at moderate concentrations and declined at higher doses, suggesting a progression toward pyroptosis. These alterations were accompanied by increased intracellular and mitochondrial ROS, mitochondrial depolarization, decreased ATP levels, and downregulation of SIRT1 and AMPK. NAC pretreatment mitigated ROS accumulation, alleviated mitochondrial impairment, and attenuated inflammasome activation. PS induce oxidative stress, mitochondrial impairment, and dysregulation of SIRT1-AMPK signaling, collectively promoting inflammasome activation in nasal epithelial cells. These findings highlight potential health risks of inhaled nanoplastics and underscore the need for further investigation into antioxidant-based protective strategies.

  PublisherDOI

• Beyond the skin barrier: optical clearing enables non-invasive cortex-wide optical coherence angiography in mice in-vivo

  bioRxiv (Cold Spring Harbor Laboratory) · 2026-03-05

  articleOpen access

  Abstract Non-invasive, high-resolution visualization of mouse brain vasculature remains challenging due to significant light scattering and absorption by mammalian tissues, hence many optical imaging protocols require scalp and/or skull excision. Here we present a fully reversible tartrazine-based optical clearing strategy that enables cortex-wide optical coherence tomography angiography (OCTA) through intact scalp and skull. We characterized tartrazine properties in the near infrared (NIR)-II band of the 1.3 µm swept-source OCTA system, confirming minimal absorption across 1.25–1.35 µm wavelength range and an effectively constant refractive index, suggesting negligible OCTA distortions. Spatially selective agent application showed that intracranial vessels emerge selectively within the treated region of interest (ROI), whereas untreated regions retain strong interference by the scalp vascular features. Depth-encoded projections and cross-sectional OCTA demonstrated an increased signal recovery at depth and an extended vessel-detection range after clearing. Vessel-map changes were quantified using intersection-over-union and Dice coefficients, yielding high similarity outside the ROI and reduced similarity within the ROI, consistent with a transition from scalp to brain vasculature. Reproducibility was confirmed in three independent 11-week-old mice and validated against scalp-removed reference OCTA. Screening tartrazine in the 0.3–0.8 Molar concentration range (7-min application) identified 0.6 M as optimal for whole-cortex scanning, balancing clearing efficacy and solution handling. Finally, the protocol generalized across mice aged 5–18 weeks. This approach provides a practical route to non-invasive structural cerebrovascular mapping with OCTA.

  PublisherOA PDFDOI

• Exosome-Mediated miRNA Delivery Restores Early Differentiation and Survival Programs in DGCR8-Deficient Mouse Embryonic Stem Cells

  International Journal of Molecular Sciences · 2026-03-25

  articleOpen access

  Pluripotent stem cell (PSC) differentiation is orchestrated by intricate autocrine and paracrine signaling networks. Among these, exosomes, key components of the cellular secretome, are implicated as crucial mediators of intercellular communication via delivery of bioactive molecules, including microRNAs (miRNAs). This study investigated the role of exosomal miRNAs in stem cell differentiation using Dgcr8-deficient mouse embryonic stem cells (mESCs), which are incapable of producing mature miRNAs. Although the differentiation capacity was markedly impaired in these cells, partial restoration was observed following treatment with exosomes derived from differentiating wild-type mESCs. Exosomal miRNA uptake was confirmed, and gene ontology analysis revealed significant enrichment of pathways associated with cell fate determination, morphogenesis, and apoptosis regulation. Kyoto Encyclopedia of Genes and Genomes pathway analysis indicated that exosomal miRNAs modulated multiple osteoinductive signaling cascades, notably the MAPK and TGF-β pathways, in Dgcr8-deficient cells. Apoptotic markers were also downregulated, suggesting a protective effect conferred by the exosomal cargo. Collectively, our results suggest that exosome-mediated delivery of miRNAs may represent a fundamental mechanism by which pluripotent stem cells coordinate stress responses and differentiation trajectories, providing novel insights into the regulation of embryogenesis.

  PublisherOA PDFDOI

• Compensation of Carrier Envelope Phase Slip using Machine Learning

  High Power Laser Science and Engineering · 2026-03-25

  articleOpen access

  We demonstrate an effective compensation of carrier-envelope-phase (CEP) slip in a high-power femtosecond laser using a machine-learning (ML)-based control scheme.The compensation is achieved through fine dispersion tuning guided by a recurrent neural network (RNN) that predicts the temporal evolution of CEP slip, combined with a reinforcement-learning (RL) that determines the optimal corrective actions.With this RNN+RL framework, the integrated CEP noise is reduced by more than a factor of two compared with a conventional proportional-integral-derivative controller.The proposed ML-based control methodology provides a versatile tool for stabilizing and optimizing various parameters in high-power laser systems.

  PublisherOA PDFDOI

• Saccadic variability in patients with Parkinson’s disease

  Journal of Neurology · 2026-03-01

  article
  PublisherDOI

• Abstract 5297: Distinct genomic and pathway-level alterations in early-onset colorectal cancer: A large-scale Korean cohort analysis

  Cancer Research · 2026-04-03

  article

  Abstract Background: Early-onset colorectal cancer (EOC) is rising in incidence globally, yet its genomic landscape in Asian populations remains inadequately characterized. Understanding molecular differences between EOC and traditional-onset colorectal cancer (TOC) is essential for clarifying age-related tumor biology. Patients and methods: Genomic profiles from 1,675 nationwide colorectal cancer patients (2017-2021) were analyzed using targeted next-generation sequencing. EOC was defined as diagnosis at ≤50 years and TOC as &amp;gt;50 years. Mutational frequencies, spectra, pathway enrichment, and co-occurrence patterns were compared between EOC and TOC using R-based pipelines, including Fisher’s exact test with FDR adjustment and maftools. Functional and protein-protein interaction analyses (DAVID, Metascape/MCODE) were performed to identify enriched pathways, and HRD-associated genes were additionally assessed for nonsense and frameshift loss-of-function variants. Results: Among 1,675 patients (428 EOC; 1,247 TOC), EOC showed higher rates of TMB-high tumors (18% vs. 12%, p = 0.009) and MSI-high tumors (5.1% vs. 2.2%, p = 0.003), indicating a greater prevalence of hypermutated phenotypes in younger individuals. EOC also demonstrated higher mutation rates in SMAD4, FAT3, and KMT2D, each increased by approximately 3-4% compared with TOC. In contrast, classical colorectal cancer drivers such as APC, KRAS, TP53, and WNT-related genes were more frequently altered in TOC. In mutational spectrum analysis, EOC exhibited a modestly higher transition-to-transversion ratio, consistent with greater intrinsic genomic instability. Pathway analysis demonstrated enrichment of NOTCH, PI3K, Hippo, TGF-β, cell-cycle, and MYC pathways in EOC, while RTK-RAS and WNT pathways predominated in TOC. Ninety-one genes showed significantly higher mutation frequencies in EOC (FDR &amp;lt; 0.05). Loss-of-function mutations in HRD-related genes (BRCA1/2, PALB2, RAD51C/D, ATM, CHEK2) were also more frequent in EOC (11.4% vs. 8%), supporting the greater contribution of homologous recombination defects in early-onset disease. Co-occurrence network analyses revealed EOC-specific clusters involving chromatin remodeling and DNA repair modules, including a dominant DNA repair supercluster (log10(P) = -16.5 to -18.6), alongside enriched epigenetic and transcriptional regulation modules. Conclusions: EOC exhibits distinct genomic and pathway-level characteristics, including higher genomic instability and enrichment of chromatin remodeling and DNA repair. These findings indicate that EOC represents a biologically unique subtype of colorectal cancer that may benefit from age-specific or HRD-targeted therapeutic strategies. Future work integrating germline sequencing with somatic profiles will help more comprehensively clarify the age-related molecular features of EOC. Citation Format: Ah Reum Lim, Boyeon Kim, Minsoo Kim, Soohyeon Lee. Distinct genomic and pathway-level alterations in early-onset colorectal cancer: A large-scale Korean cohort analysis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2026; Part 1 (Regular Abstracts); 2026 Apr 17-22; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2026;86(7 Suppl):Abstract nr 5297.

  PublisherDOI

• Discontinuation of Beta-Blocker Therapy after Myocardial Infarction

  New England Journal of Medicine · 2026-03-30 · 2 citations

  article

  BACKGROUND: The role of long-term beta-blocker therapy after a myocardial infarction in patients without left ventricular systolic dysfunction or heart failure is unclear in the era of contemporary coronary-artery reperfusion and secondary prevention interventions. METHODS: We conducted an open-label, randomized, noninferiority trial at 25 centers in South Korea. Patients whose condition remained stable after a myocardial infarction, who had a left ventricular ejection fraction of at least 40% and no heart failure, and who had received beta-blocker therapy for at least 1 year after the myocardial infarction were randomly assigned in a 1:1 ratio to discontinue or to continue beta-blocker therapy. The primary end point was a composite of death from any cause, recurrent myocardial infarction, or hospitalization for heart failure. The prespecified noninferiority margin was an upper limit of the 95% confidence interval for the hazard ratio of 1.4. RESULTS: A total of 2540 patients underwent randomization; 1246 were assigned to beta-blocker discontinuation and 1294 to beta-blocker continuation. The mean age of the patients was 63.2 years, and 12.8% were women. At a median follow-up of 3.1 years (interquartile range, 2.5 to 3.5), a primary end-point event had occurred in 58 patients (4-year Kaplan-Meier estimate, 7.2%) in the discontinuation group and in 74 patients (4-year Kaplan-Meier estimate, 9.0%) in the continuation group (hazard ratio, 0.80; 95% confidence interval, 0.57 to 1.13; P = 0.001 for noninferiority). The incidence of serious adverse events was similar in the two groups. CONCLUSIONS: Among patients who received beta-blocker therapy beyond the first year after a myocardial infarction, discontinuation of beta-blocker therapy was noninferior to continuation with respect to a composite of death from any cause, recurrent myocardial infarction, or hospitalization for heart failure. (Funded by Patient-Centered Clinical Research Coordinating Center in the Ministry of Health and Welfare, South Korea; SMART-DECISION ClinicalTrials.gov number, NCT04769362.).

  PublisherDOI

• Dual-Distillation Vision-Language Model for Multimodal Emotion Recognition in Conversation with Quantized Edge Deployment

  Applied Sciences · 2026-03-23

  articleOpen access

  Multimodal Emotion Recognition in Conversation (ERC) has attracted attention as a key technology in human–computer interaction, mental healthcare, and intelligent services. However, deploying ERC in real-world settings remains challenging due to reliability gaps across modalities, instability in visual representations, and the high computational cost of large pretrained models. In particular, on resource-constrained edge devices, it is difficult to reduce model size and inference latency while preserving accuracy. To address these challenges, we jointly propose a knowledge-distillation-based multimodal ERC model, called DDVLM, with an edge-optimized Weight-Only Quantization (WOQ) pipeline for efficient edge deployment. DDVLM assigns the textual modality as the teacher and the visual modality as the student, transferring emotion-distribution knowledge to improve non-verbal representations and stabilize multimodal learning. In addition, Exponential Moving Average (EMA)-based self-distillation enhances the consistency and generalization capability of text features. Meanwhile, the proposed WOQ pipeline quantizes linear-layer weights to INT8 while preserving precision-sensitive operations in mixed precision, thereby minimizing accuracy loss and reducing model size, memory usage, and inference latency. Experiments on the MELD dataset demonstrated that the proposed approach achieves state-of-the-art performance while also enabling real-time inference on edge devices such as NVIDIA Jetson. Overall, this work presents a practical ERC framework that jointly considers accuracy and deployability.

  PublisherOA PDFDOI

• Metabotropic glutamate receptor 5 expression associates with pain and inflammatory pathways in interstitial cystitis

  Scientific Reports · 2026-03-11

  articleOpen access

  Interstitial cystitis (IC)/bladder pain syndrome (BPS) is a chronic condition with severe pelvic pain and urinary symptoms significantly impairing quality of life. This study investigated the clinical relevance of the metabotropic glutamate receptor (mGluR) family in IC/BPS. Bladder biopsy samples were taken from 61 patients, including 42 Hunner-type IC, 11 non-Hunner type IC, and 8 controls without IC. Gene expression analysis revealed that mGluR2, mGluR3, and mGluR5 were significantly elevated in patients with IC/BPS compared to controls. Among these, mGluR5 showed the strongest association with pain severity, fibrosis, and lymphoplasmacytic infiltration. Patients with Hunner-type IC also exhibited increased expression of p65 and interleukin-1β, suggesting activation of inflammatory response modulation in IC/BPS. These findings suggest that mGluR5 may contribute to pain through immune response modulation in IC/BPS. Targeting mGluR5 could represent a promising therapeutic strategy to alleviate symptoms and improve patient quality of life.

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Recent grants

• NIH Grant R01NS033008

  NIH · $3.2M · 2011

• NIH Grant R01NS028752

  NIH · $3.6M · 2010

• NIH Grant P01NS023349

  NIH · $25.5M · 2008

• NIH Grant R01AI015446

  NIH · $1.3M · 2001

• NIH Grant P60AR030692

  NIH · $15.5M · 2002

Frequent coauthors

• Suk Ho Bhang

  Sungkyunkwan University

  158 shared

• David Mooney

  113 shared

• Joseph P. Vacanti

  Harvard University

  107 shared

• Tae‐Jin Lee

  Chung-Ang University

  91 shared

• Seung‐Woo Cho

  Kangwon National University

  81 shared

• Sun‐Woong Kang

  Korea Institute of Toxicology

  67 shared

• Seok Jin Kim

  Sungkyunkwan University

  59 shared

• Stephen S. Kim

  Inova Children's Hospital

  59 shared

Education

• M.D.

  Brigham and Women's Hospital, Harvard Medical School