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Effects of spatiotemporal coherence on interferometric microscopy
Shin, Seungwoo,Kim, Kyoohyun,Lee, KyeoReh,Lee, SangYun,Park, YongKeun The Optical Society 2017 Optics express Vol.25 No.7
<P>Illumination coherence plays a major role in various imaging systems, from microscopy, metrology, digital holography, optical coherence tomography, to ultrasound imaging. Here, we present a systematic study on the effects of degrees of spatiotemporal coherence of an illumination (DSTCI) on imaging quality of interferometric microscopy. An optical field with arbitrary DSTCI was decomposed into wavelets with constituent spatiotemporal frequencies, and the effects on image quality were quantitatively investigated. The results show the synergistic effects on reduction of speckle noise when DSTCI is decreased. This study presents a method to systematically control DSTCI, and the result provides an essential reference on the effects of DSTCI on the imaging quality. We believe that the presented methods and results can be implemented in various imaging systems for characterizing and improving the imaging quality. (C) 2017 Optical Society of America</P>
Epidemiology of Surfing-related Injuries in South Korea: Type, Location and Mechanism
( Seungwoo Shin ),( Juseong Lee ),( Junghoon Kim ) 대한운동사협회 2022 대한운동사협회 운동사대회자료집 Vol.2022 No.-
OBJECTIVES Although the surfing-related injuries has been increasing with growing numbers of recreational surfers worldwide, lack of epidemiological evidence about the surfing injuries. Therefore, the purpose of this study was to identify the types and causes of injury in recreational surfers. We also aimed to determine the differences in the type and cause of injury according to surfer’s characteristics (sex and surfing experience). METHODS A total of 227 participants (149 male and 78 female) in South Korea were recruited and analyzed for this study. To identify the injury related to surfing, we investigated the types, locations, season, and causes of injury using a questionnaire. RESULTS The highest frequency of injury was found in skin, followed by muscle and tendon, ligaments, and joints. There were not significant differences in the injury types according to the sex and surfing experience (≤12 versus >12 months). An upper limb and arm injury was significantly higher in male (p<0.01) and the torso injury was higher in female (p<0.05). Moreover, the less experience (≤12 months) of surfing was associated with higher rates of injury caused by falling or collision with other surfers. CONCLUSIONS To the best of our knowledge, this is the first epidemiological study presented the surfing related injury among Korean population. We found the injuries mainly occurred on the skin, and muscle and tendon. In addition, our results suggest that surfers with insufficient experience may be vulnerable to injuries from falls and contact with other surfers. Consequently, these epidemiological data may be utilized to prevent and manage the injury in surfers according to surfer’s characteristic and experience.
Shin, Seungwoo,Kim, Jihye,Lee, Je-Ryung,Jeon, Eun-chae,Je, Tae-Jin,Lee, Wonhee,Park, YongKeun The Royal Society of Chemistry 2018 Lab on a chip Vol.18 No.22
<P>Optical diffraction tomography (ODT) enables the reconstruction of the three-dimensional (3D) refractive-index (RI) distribution of a biological cell, which provides invaluable information for cellular and subcellular structures in a non-invasive manner. However, ODT suffers from an inferior axial resolution, due to the limited accessible angles imposed by the numerical aperture of the objective lens. In this study, we propose and experimentally demonstrate an approach to enhance the 3D reconstruction performance in ODT. By employing trapezoidal micromirrors, side scattered signals from the sample are measured for various side plane-wave-illumination angles. By combining the side scattered fields with the forward scattered fields, the axial resolution and 3D image quality of ODT are improved, without changing optical instruments. The feasibility and applicability of the proposed method are demonstrated by reconstructing the 3D RI distribution of a red blood cell and HeLa cells in hydrogel. We also present systematic analyses of the improved 3D imaging performance using numerical simulations and experimental measurements for the 3D transfer function, a point object, and a microsphere. The analyses demonstrate an improved axial resolution of 0.31 μm, 4.8 times smaller than that of the conventional method. The proposed method enables the non-invasive and accurate 3D imaging of 3D cultured cells, which is crucial for cell biology studies.</P>
Seungwoo Kim,Youngmi Shin,Youngju Shin,Yang-Seo Park,조남정 한국분자세포생물학회 2008 Molecules and cells Vol.25 No.4
Three G-protein-linked acetylcholine receptors (GARs) exist in the nematode C. elegans. GAR-3 is pharmacologically most similar to mammalian muscarinic acetylcholine receptors (mAChRs). We observed that carbachol stimulated ERK1/2 activation in Chinese hamster ovary (CHO) cells stably expressing GAR-3b, the predominant alternatively spliced isoform of GAR-3. This effect was substantially reduced by the phospholipase C (PLC) inhibitor U73122 and the protein kinase C (PKC) inhibitor GF109203X, implying that PLC and PKC are involved in this process. On the other hand, GAR-3b-mediated ERK1/2 activation was inhibited by treatment with forskolin, an adenylate cyclase (AC) activator. This inhibitory effect was blocked by H89, an inhibitor of cAMP-dependent protein kinase A (PKA). These results suggest that GAR-3b-mediated ERK1/2 activation is negatively regulated by cAMP through PKA. Together our data show that GAR-3b mediates ERK1/2 activation in CHO cells and that GAR-3b can couple to both stimulatory and inhibitory pathways to modulate ERK1/2.
Seungwoo Kim,Joong-Keun Shin,Hyung Shin Yoon,Jeong-Hoon Kim 대한생리학회-대한약리학회 2011 The Korean Journal of Physiology & Pharmacology Vol.15 No.6
Repeated administration of psychostimulants such as cocaine leads to the development of behavioral sensitization. Extracellular signal-Regulated Kinase (ERK), an enzyme important for long-term neuronal plasticity, has been implicated in such effects of these drugs. Although the nucleus accumbens (NAcc) is the site mediating the expression of behavioral sensitization by drugs of abuse, the precise role of ERK activation in this site has not been determined. In this study we demonstrate that blockade of ERK phosphorylation in the NAcc by a single bilateral microinjections of PD98059 (0.5 or 2.0Ռg/ side), or U0126 (0.1 or 1.0Ռg/side), into this site dose-dependently inhibited the expression of cocaine-induced behavioral sensitization when measured at day 7 following 6 consecutive daily cocaine injections (15 mg/kg, i.p.). Acute microinjection of either vehicle or PD98059 alone produced no different locomotor activity compared to saline control. Further, microinjection of PD98059 (2.0Ռg/side) in the NAcc specifically lowered cocaine-induced increase of ERK phosphorylation levels in this site, while unaffecting p-38 protein levels. These results indicate that ERK activation in the NAcc is necessary for the expression of cocaine-induced behavioral sensitization, and further suggest that repeated cocaine evokes neuronal plasticity involving ERK pathway in this site leading to long-lasting behavioral changes.
Kim, Seungwoo,Shin, Youngmi,Shin, Youngju,Park, Yang-Seo,Cho, Nam Jeong Korean Society for Molecular Biology 2008 Molecules and cells Vol.25 No.4
Three G-protein-linked acetylcholine receptors (GARs) exist in the nematode C. elegans. GAR-3 is pharmacologically most similar to mammalian muscarinic acetylcholine receptors (mAChRs). We observed that carbachol stimulated ERK1/2 activation in Chinese hamster ovary (CHO) cells stably expressing GAR-3b, the predominant alternatively spliced isoform of GAR-3. This effect was substantially reduced by the phospholipase C (PLC) inhibitor U73122 and the protein kinase C (PKC) inhibitor GF109203X, implying that PLC and PKC are involved in this process. On the other hand, GAR-3b-mediated ERK1/2 activation was inhibited by treatment with forskolin, an adenylate cyclase (AC) activator. This inhibitory effect was blocked by H89, an inhibitor of cAMP-dependent protein kinase A (PKA). These results suggest that GAR-3b-mediated ERK1/2 activation is negatively regulated by cAMP through PKA. Together our data show that GAR-3b mediates ERK1/2 activation in CHO cells and that GAR-3b can couple to both stimulatory and inhibitory pathways to modulate ERK1/2.
저유전율을 위한 다공성 실리카 나노입자 하이브리드 폴리이미드 필름의 구현
신승우(Seungwoo Shin),김석(Seok Kim),강동필(Dong Pil Kang),최광민(Kwang-Min Choi),한상철(Sang-Cheol Han),조영태(Young Tae Cho) 한국기계가공학회 2023 한국기계가공학회지 Vol.22 No.3
As semiconductor manufacturing technology continues to advance, researchers are exploring the production of devices in ever-smaller sizes. The benefits of utilizing a low-k material as an insulating film become increasingly pronounced as device dimensions decrease. Researchers have spent years investigating and developing low-k materials for device integration in order to mitigate the delay and signal loss that arise with faster data processing and transmission speeds. Recently, porous materials that employ air with a low dielectric constant, such as airgel and polymer airgel, have emerged as promising low-k materials. To contribute to this field, the present study fabricated nano-silica hybrid polyimide films that incorporate mesoporous silica nanoparticles, with the goal of developing low-k materials. The dielectric constant was measured to evaluate whether polyimide containing MSN could be employed as a low-k material.