이사람 교수
Sa Ram Lee
서울대학교 · 공학
연구실 소개
이 교수의 연구실은 비침습적 생체신호 측정 및 분석을 핵심으로 하며, 특히 혈압 모니터링과 순환세포 검출 기술에 초점을 맞추고 있습니다. 전자기(ECG)와 광plethysmography(PPG)를 기반으로 한 혈압 추정 모델 개발과 함께, 스마트워치 등 웨어러블 기기에서의 정확한 신호 추출을 위한 노이즈 제거 기술도 연구하고 있습니다. 또한, 약물의 혈관내 흡착 현상에 영향을 미치는 생체재료의 특성 분석을 통해 약물 치료의 정밀도를 높이는 데 기여하고 있습니다.
연구 현황
연구 성과 추이
표시된 성과는 수집된 데이터 기준으로 산출되며, 일부 차이가 있을 수 있습니다.
주요 논문
15Quantification of circulating tumor cells (CTCs) in blood samples is believed to provide valuable evidence of cancer progression, cancer activity status, response to therapy in patients with metastatic cancer, and possible cancer diagnosis. Recently, a number of researchers reported that CTCs tend to lose their epithelial cell adhesion molecule (EpCAM) by an epithelial-mesenchymal transition (EMT). As such, label-free CTC detection methods are attracting worldwide attention. Here, we describe a
As non-invasive continuous blood pressure monitoring (NCBPM) has gained wide attraction in the recent decades, many pulse arrival time (PAT) or pulse transit time (PTT) based blood pressure (BP) estimation studies have been conducted. However, most of the studies have used small homogeneous subject pools to generate models of BP based on particular interventions for induced hemodynamic change. In this study, a large open biosignal database from a diverse group of 2309 surgical patients was analy
Although various predictors and methods for BP estimation have been proposed, differences in study designs have led to difficulties in determining the optimal method. This study presents analyses of BP estimation methods using 2.4 million cardiac cycles of two commonly used non-invasive biosignals, electrocardiogram (ECG) and photoplethysmogram (PPG), from 1376 surgical patients. Feature selection methods were used to determine the best subset of predictors from a total of 42 including PAT, hear
Photoplethysmography (PPG) has become ubiquitous with the development of smart watches and the mobile healthcare market. However, PPG is vulnerable to various types of noises that are ever present in uncontrolled environments, and the key to obtaining meaningful signals depends on successful denoising of PPG. In this context, algorithms have been developed to denoise PPG, but many were validated in controlled settings or are reliant on multiple steps that must all work correctly. This paper prop
We quantified the influence of the elements of the extracorporeal oxygenation (ECMO) circuit on drug sequestration by focusing on the interactions between materials and drugs. Tubing of three different brands (Tygon/Maquet/Terumo) and oxygenators of two different brands (Maquet/Terumo) were used. Drugs included dexmedetomidine, meropenem, and heparin, which were dissolved in deionized water. Tubing was cut into approximately 7 cm sections and allowed drug solutions enclosed inside by clamping bo
The proposed pulse pressure estimation method provides accurate estimates in situations with and without significant changes in stroke volume. The proposed method improves upon the currently available systolic blood pressure estimation methods by providing accurate pulse pressure estimates.
Detection of pathogenic bacteria requires a sensitive, accurate, rapid, and portable device. Given that lethal microbes are of various sizes, bacterial sensors based on DC (direct current) impedance on chips should be equipped with channels with commensurate cross sections. When it comes to counting and interrogation of individual bacteria on a microfluidic chip, very narrow channels are required, which are neither easy nor cost-effective to fabricate. Here, we report a flow cytometry-based subm
Continuous blood pressure (BP) monitoring in daily life is needed to enable early detection of hypertension and improve its control. Although pulse transit time (PTT)-based BP estimation represents a promising approach, it still lacks of performance in systolic blood pressure (SBP) estimation and its use in daily life is limited owing to the requirement of bulky systems for measurement of PTT. This study aims at developing a wearable system providing continuous PTT measurement and enhanced SBP e
Introducing IoT-based technology to clinical sites, including medical institutions, will enhance the quality of medical services, increase patient safety, improve management efficiency, and promote patient-centered medical services. Moreover, the IoT is expected to play an active role in the five major tasks of facility hygiene in medical fields, which are all required to deal with the COVID-19 pandemic: social distancing, contact tracking, bed occupancy control, and air quality management. Ulti
In this study, in situ surface-enhanced Raman scattering (SERS) decoding was demonstrated in microfluidic chips using novel thin micro gold shells modified with Raman tags. The micro gold shells were fabricated using electroless gold plating on PMMA beads with diameter of 15 microm. These shells were sophisticatedly optimized to produce the maximum SERS intensity, which minimized the exposure time for quick and safe decoding. The shell surfaces produced well-defined SERS spectra even at an extre
Kruppel-like factor 2 (KLF2) regulates endothelial cell metabolism; endothelial dysfunction is associated with hypertension and is a predictor of atherosclerosis development and cardiovascular events. Here, we investigated the role of KLF2 in hypertensive nephropathy by regulating KLF2 expression in human primary glomerular endothelial cells (hPGECs) and evaluating this expression in the kidney tissues of a 5/6 nephrectomy mouse model as well as patients with hypertension. Hypertension-mimicking
These results indicate that the proposed model is generalizable and effective in predicting sleep stages using features which can be extracted from non-contact sleep monitors. This holds valuable implications for future development of home sleep evaluation systems.
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