24 results on '"Sung Chan, Lee"'
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2. Optical visualisation of thermogenesis in stimulated single-cell brown adipocytes
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Rókus Kriszt, Satoshi Arai, Hideki Itoh, Michelle H. Lee, Anna G. Goralczyk, Xiu Min Ang, Aaron M. Cypess, Andrew P. White, Farnaz Shamsi, Ruidan Xue, Jung Yeol Lee, Sung-Chan Lee, Yanyan Hou, Tetsuya Kitaguchi, Thankiah Sudhaharan, Shin’ichi Ishiwata, E. Birgitte Lane, Young-Tae Chang, Yu-Hua Tseng, Madoka Suzuki, and Michael Raghunath
- Subjects
Medicine ,Science - Abstract
Abstract The identification of brown adipose deposits in adults has led to significant interest in targeting this metabolically active tissue for treatment of obesity and diabetes. Improved methods for the direct measurement of heat production as the signature function of brown adipocytes (BAs), particularly at the single cell level, would be of substantial benefit to these ongoing efforts. Here, we report the first application of a small molecule-type thermosensitive fluorescent dye, ERthermAC, to monitor thermogenesis in BAs derived from murine brown fat precursors and in human brown fat cells differentiated from human neck brown preadipocytes. ERthermAC accumulated in the endoplasmic reticulum of BAs and displayed a marked change in fluorescence intensity in response to adrenergic stimulation of cells, which corresponded to temperature change. ERthermAC fluorescence intensity profiles were congruent with mitochondrial depolarisation events visualised by the JC-1 probe. Moreover, the averaged fluorescence intensity changes across a population of cells correlated well with dynamic changes such as thermal power, oxygen consumption, and extracellular acidification rates. These findings suggest ERthermAC as a promising new tool for studying thermogenic function in brown adipocytes of both murine and human origins.
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- 2017
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3. Behavioral and Electrophysiological Effects of Ajowan (Trachyspermum ammi Sprague) (Apiales: Apiaceae) Essential Oil and Its Constituents on Nymphal and Adult Bean Bugs, Riptortus clavatus (Thunberg) (Hemiptera: Alydidae)
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Sung-Chan Lee, Seon-Mi Seo, Min-Jung Huh, Jun-Hyeong Kwon, Il Nam, Ji-Hong Park, and Il-Kwon Park
- Subjects
repellent activity ,ajowan essential oil ,carvacrol ,thymol ,bean bug ,riptortus calvatus ,push-pull strategy ,Science - Abstract
We investigated the repellent effect of 12 Apiaceae plant essential oils on nymphal and adult (male and female) forms of the bean bug, Riptortus clavatus (Thunberg) (Hemiptera: Alydidae), using a four-arm olfactometer. Among the essential oils tested, ajowan (Trachyspermum ammi Sprague) essential oil showed the strongest repellent activity against the nymphal and adult bean bugs. For female adults, the repellent activity was significantly different between an ajowan oil-treated chamber and an untreated chamber down to a concentration of 14.15 μg/cm2. We also investigated the repellent activity of individual ajowan essential oil constituents. Of the compounds examined, carvacrol and thymol showed the most potent repellent activity against the nymphal and adult bean bugs. Carvacrol and thymol exhibited 73.08% and 70.0% repellent activity for the bean bug nymph at 0.71 and 2.83 μg/cm2, respectively, and 82.6% and 80.7% at 5.66 and 11.32 μg/cm2, respectively, for male adults. Carvacrol and thymol exhibited strong repellent activity against female adult bean bugs down to a concentration of 2.83 μg/cm2. Ajowan essential oil, thymol and carvacrol elicited a negative electroantennogram (EAG) response from adult bean bugs. This could explain the repellent activity of ajowan essential oil and its constituents. Our results indicate that ajowan essential oil and its constituents carvacrol and thymol can be potential candidates as the ‘push’ component in a ‘push-pull’ strategy for bean bug control.
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- 2020
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4. Fumigant Antifungal Activity via Reactive Oxygen Species of Thymus vulgaris and Satureja hortensis Essential Oils and Constituents against Raffaelea quercus-mongolicae and Rhizoctonia solani
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Jeong-Eun Kim, Ji-Eun Lee, Min-Jung Huh, Sung-Chan Lee, Seon-Mi Seo, Jun Hyeong Kwon, and Il-Kwon Park
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thymus vulgaris ,satureja hortensis ,antifungal activity ,reactive oxygen species ,thymol ,carvacrol ,Microbiology ,QR1-502 - Abstract
In this study, the fumigant antifungal activity of 10 Lamiaceae plant essential oils was evaluated against two phytopathogenic fungi, Raffaelea quercus-mongolicae, and Rhizoctonia solani. Among the tested essential oils, thyme white (Thymus vulgaris) and summer savory (Satureja hortensis) essential oils exhibited the strongest fumigant antifungal activity against the phytopathogenic fungi. We analyzed the chemical composition of two active essential oils and tested the fumigant antifungal activities of the identified compounds. Among the tested compounds, thymol and carvacrol had potent fumigant antifungal activity. We observed reactive oxygen species (ROS) generation in two fungi treated with thymol and carvacrol. Confocal laser scanning microscopy images of fungi stained with propidium iodide showed that thymol and carvacrol disrupted fungal cell membranes. Our results indicated that ROS generated by thymol and carvacrol damaged the cell membrane of R. querqus-mongolicae and R. solani, causing cell death.
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- 2019
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5. Imaging inflammation using an activated macrophage probe with Slc18b1 as the activation-selective gating target
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Heon Seok Kim, Beomsue Kim, Jong-Jin Kim, Jun-Young Kim, Sungjin Park, Sivaraman Balasubramaniam, Sung-Chan Lee, Sejong Choi, Jin-Soo Kim, Jung Yeol Lee, Nam-Young Kang, Yong-An Lee, and Young-Tae Chang
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0301 basic medicine ,Mice, Knockout, ApoE ,Science ,Molecular Probe Techniques ,General Physics and Astronomy ,Inflammation ,02 engineering and technology ,Gating ,Article ,General Biochemistry, Genetics and Molecular Biology ,Mice ,03 medical and health sciences ,In vivo ,medicine ,Animals ,Humans ,Macrophage ,lcsh:Science ,Cation Transport Proteins ,Multidisciplinary ,Chemistry ,Transporter ,General Chemistry ,Macrophage Activation ,021001 nanoscience & nanotechnology ,Small molecule ,Plaque, Atherosclerotic ,Cell biology ,RAW 264.7 Cells ,030104 developmental biology ,Molecular Probes ,Acridines ,lcsh:Q ,CRISPR-Cas Systems ,medicine.symptom ,0210 nano-technology ,Molecular probe ,HeLa Cells - Abstract
Activated macrophages have the potential to be ideal targets for imaging inflammation. However, probe selectivity over non-activated macrophages and probe delivery to target tissue have been challenging. Here, we report a small molecule probe specific for activated macrophages, called CDg16, and demonstrate its application to visualizing inflammatory atherosclerotic plaques in vivo. Through a systematic transporter screen using a CRISPR activation library, we identify the orphan transporter Slc18b1/SLC18B1 as the gating target of CDg16., Attempts to image activated macrophages in vivo have been hampered by selectivity and delivery problems. Here the authors develop a small molecule fluorescent probe specific to activated M1 and M2 macrophages, identify the orphan receptor Slc18b1/SLC18B1 as the mechanism of uptake, and use it to image atherosclerosis in mice.
- Published
- 2019
6. Nematicidal Activity of 3-Acyltetramic Acid Analogues Against Pine Wood Nematode, Bursaphelenchus xylophilus
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Hyo-Rim Lee, Sung-Chan Lee, Ji-Eun Lee, Seon-Mi Seo, Yong-Chul Jeong, Chan-Sik Jung, Mark G. Moloney, and Il-Kwon Park
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pine wilt disease ,pine wood nematode ,toxicity ,lead compounds ,3-acyltetramic acid analogues ,Organic chemistry ,QD241-441 - Abstract
Among 98 3-acyltetramic acid analogues, compounds 1c, 2c, 2f and 2g, showed >90% nematicidal activity against the pine wood nematode Bursaphelenchus xylophilus at a 10 μg/mL concentration. The nematicidal activities of compounds 1d, 1h, and 2k were a little lower at 88.0%, 85.8%, and 57.2% at a 10 μg/mL concentration, respectively. The nematicidal activity of emamection benzoate, widely used in Korea for the prevention of pine wilt disease, was 32.3% at a 10 μg/mL concentration. Other 3-acyltetramic acid analogues showed less than 30% nematicidal activity. A structure-activity relationship study indicated that the chain length of the C-acyl substituent was very important for high nematicidal activity. All active compounds had C13H27 or C11H23 acyl substituents, in two closely related groups with the common physicochemical properties of a polar surface area 57.6A2, PSA (polar surface area) 7.8–8.6% and ClogP (calculated partition coefficient) 5.1–5.9 and a polar surface area 75–84A2, PSA 11.1–11.6% and ClogP 4.7–5.1, respectively. Our study indicates that active 3-acyltetramic acid analogues could have potential as lead compounds for developing novel pine wood nematode control agents.
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- 2017
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7. Development of a Customized Endoscopic Dual-Diffusing Optical Fiber Probe for Pancreatic Cancer Therapy: Toward Clinical Use.
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Hyunseon Yu, Sung Chan Lee, Gaye Park, Jaesun Kim, Hyunjoo Kim, Seung Ho Cho, and Byungjo Jung
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OPTICAL fibers , *PANCREATIC cancer , *CANCER treatment , *PANCREATIC duct , *THERMOMECHANICAL properties of metals , *ANISOMETROPIA , *ENDOSCOPIC ultrasonography , *NEEDLES & pins , *PANCREATIC tumors - Abstract
Objective: We developed a dual-diffusing optical fiber probe (DDOFP), capable of uniformly illuminating the anatomical structure of pancreatic duct for photodynamic therapy (PDT) of pancreatic cancer in clinical settings. Background: Optical fiber presents a unique route for pancreatic PDT by enabling access to the pancreatic duct. For effective pancreatic PDT, the optical fiber should produce a uniform illumination covering of the pancreatic duct, while maintaining its transmission property under thermomechanical stresses in surgical environments. Methods: The transmission profiles of DDOFP were measured using a charge-coupled device (CCD) camera at two directions: front-spherical and side-cylindrical areas of the optical fiber. We simulated the change in transmission property by curved tube structures using optically transparent phantom. DDOFP was integrated with 19-gauge needle catheter that is commercially used as an optical guide to treat pancreatic cancer. The temperature of DDOFP was measured at the end face using a thermistor probe in the bovine tissue, while delivering laser energy of over 200 and 500 J. Results: DDOFP was customized to secure the inner diameter of the 19-gauge needle catheter of 686 lm to be integrated as a clinical device. The round ball lens fiber tip minimized the back-burn effect caused by blood carbonization during surgery and induced front-spherical diffusion. DDOFP produced uniform light illumination with intensity difference of <10%. When DDOFP was bent with a small curvature <15 mm, the transmission intensity was consistent. Under high-power laser transmission, DDOFP was found to be robust to cracking or deformation. Conclusions: DDOFP was customized for pancreatic PDT with superior thermomechanical property and uniform light illumination at both the front-spherical and side-cylindrical areas. This is the smallest clinically available optical fiber per our knowledge and officially approved by the Korea Food and Drug Administration (item approval number: 17-516). DDOFP can contribute immensely toward the efficient delivery of pancreatic PDT and photothermal therapy. [ABSTRACT FROM AUTHOR]
- Published
- 2022
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8. Fumigant Antifungal Activity via Reactive Oxygen Species of Thymus vulgaris and Satureja hortensis Essential Oils and Constituents Against Raffaelea quercus-mongolicae and Rhizoctonia solani
- Author
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Min-Jung Huh, Sung-Chan Lee, Seon-Mi Seo, Jun Hyeong Kwon, Ji-Eun Lee, Il-Kwon Park, and Jeongeun Kim
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Thymus vulgaris ,carvacrol ,lcsh:QR1-502 ,01 natural sciences ,Biochemistry ,lcsh:Microbiology ,Rhizoctonia solani ,chemistry.chemical_compound ,food ,thymol ,Carvacrol ,Food science ,Propidium iodide ,Molecular Biology ,Thymol ,chemistry.chemical_classification ,reactive oxygen species ,Reactive oxygen species ,biology ,010405 organic chemistry ,Chemistry ,antifungal activity ,biology.organism_classification ,food.food ,0104 chemical sciences ,010404 medicinal & biomolecular chemistry ,Lamiaceae ,Satureja hortensis - Abstract
In this study, the fumigant antifungal activity of 10 Lamiaceae plant essential oils was evaluated against two phytopathogenic fungi, Raffaelea quercus-mongolicae, and Rhizoctonia solani. Among the tested essential oils, thyme white (Thymus vulgaris) and summer savory (Satureja hortensis) essential oils exhibited the strongest fumigant antifungal activity against the phytopathogenic fungi. We analyzed the chemical composition of two active essential oils and tested the fumigant antifungal activities of the identified compounds. Among the tested compounds, thymol and carvacrol had potent fumigant antifungal activity. We observed reactive oxygen species (ROS) generation in two fungi treated with thymol and carvacrol. Confocal laser scanning microscopy images of fungi stained with propidium iodide showed that thymol and carvacrol disrupted fungal cell membranes. Our results indicated that ROS generated by thymol and carvacrol damaged the cell membrane of R. querqus-mongolicae and R. solani, causing cell death.
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- 2019
- Full Text
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9. Effects of vegetation on soundscape of an urban religious precinct : case study of Myeong-dong cathedral in Seoul
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Sung Chan Lee, Joo Young Hong, In Hwan Hwang, Yong Hee Kim, and School of Electrical and Electronic Engineering
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Soundscape ,Environmental Engineering ,Vegetation ,Urban Space ,Precinct ,Geography, Planning and Development ,0211 other engineering and technologies ,Survey result ,02 engineering and technology ,Building and Construction ,010501 environmental sciences ,01 natural sciences ,Geography ,Engineering::Electrical and electronic engineering [DRNTU] ,Participant perceptions ,medicine ,021108 energy ,Physical geography ,medicine.symptom ,Vegetation (pathology) ,Urban space ,0105 earth and related environmental sciences ,Civil and Structural Engineering ,Noise propagation - Abstract
This study investigates the effect of vegetation for noise reduction and the changes in the soundscape of an access road to a religious space in Seoul. The noise propagation was investigated by performing field measurements before vegetation covered with soil, one month after, and four years after vegetation, and the overall soundscape perception was studied by conducting a social survey. The vegetation was added to the access road of the Myeong-dong Catholic Cathedral precinct, which is responsible for religious and social functions. As the vegetation became established, the sound pressure level tended to be reduced more, with particularly significant decreases in the 1 kHz and higher bands. Furthermore, before vegetation covered with soil and immediately after vegetation, the reverberation time varied between 1 and 2 s; however, as the planted trees grew and their leaf canopies became thicker, the reverberation time was reduced to 1.2 s or less. Consequently, the speech transmission index was improved four years after vegetation. The survey results showed that the participant perceptions of the overall quality and acoustic quality increased at statistically significant levels, but the increase in the perceived visual quality was not statistically significant. Accepted version
- Published
- 2019
10. Nematicidal activity of 3-acyltetramic acid analogues against pine wood nematode, Bursaphelenchus xylophilus
- Author
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Seon-Mi Seo, Yong-Chul Jeong, Il-Kwon Park, Ji-Eun Lee, Hyo-Rim Lee, Sung-Chan Lee, Mark G. Moloney, and Chan-Sik Jung
- Subjects
Tylenchida ,Surface Properties ,Substituent ,Pharmaceutical Science ,Bursaphelenchus xylophilus ,010402 general chemistry ,01 natural sciences ,Article ,Analytical Chemistry ,Polar surface area ,lcsh:QD241-441 ,chemistry.chemical_compound ,Structure-Activity Relationship ,lcsh:Organic chemistry ,Drug Discovery ,Botany ,lead compounds ,Structure–activity relationship ,Animals ,pine wood nematode ,Food science ,Physical and Theoretical Chemistry ,Wilt disease ,pine wilt disease ,toxicity ,3-acyltetramic acid analogues ,biology ,Molecular Structure ,010405 organic chemistry ,Antinematodal Agents ,Organic Chemistry ,biology.organism_classification ,Pinus ,Pyrrolidinones ,0104 chemical sciences ,Partition coefficient ,Nematode ,chemistry ,Chemistry (miscellaneous) ,Pine wood ,Molecular Medicine - Abstract
Among 98 3-acyltetramic acid analogues, compounds 1c, 2c, 2f and 2g, showed >90% nematicidal activity against the pine wood nematode Bursaphelenchus xylophilus at a 10 μg/mL concentration. The nematicidal activities of compounds 1d, 1h, and 2k were a little lower at 88.0%, 85.8%, and 57.2% at a 10 μg/mL concentration, respectively. The nematicidal activity of emamection benzoate, widely used in Korea for the prevention of pine wilt disease, was 32.3% at a 10 μg/mL concentration. Other 3-acyltetramic acid analogues showed less than 30% nematicidal activity. A structure-activity relationship study indicated that the chain length of the C-acyl substituent was very important for high nematicidal activity. All active compounds had C13H27 or C11H23 acyl substituents, in two closely related groups with the common physicochemical properties of a polar surface area 57.6A2, PSA (polar surface area) 7.8–8.6% and ClogP (calculated partition coefficient) 5.1–5.9 and a polar surface area 75–84A2, PSA 11.1–11.6% and ClogP 4.7–5.1, respectively. Our study indicates that active 3-acyltetramic acid analogues could have potential as lead compounds for developing novel pine wood nematode control agents.
- Published
- 2017
- Full Text
- View/download PDF
11. Band-gap nonlinearity in perovskite structured solid solutions
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Soonil Lee, Levi, Roni D., Weiguo Qu, Sung Chan Lee, and Randall, CLive A.
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Barium compounds -- Optical properties ,Barium compounds -- Thermal properties ,Perovskite -- Structure ,Perovskite -- Optical properties ,Perovskite -- Thermal properties ,Strontium -- Optical properties ,Strontium -- Thermal properties ,Ultraviolet spectroscopy -- Usage ,Physics - Abstract
Compositional effects on optical band-gap energy using end members of AB[O.sub.3] perovskites are examined by an optical absorption with a UV-spectroscopy. The studies have shown that along with high temperature phases, low temperature displacive phase transitions and complex nonchiometry have perturbed the band-gap variation in perovskite oxide materials.
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- 2010
12. A Molecular Fluorescent Probe for Targeted Visualization of Temperature at the Endoplasmic Reticulum
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Duanting Zhai, Madoka Suzuki, Satoshi Arai, Sung-Chan Lee, and Young-Tae Chang
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Cytoplasm ,Multidisciplinary ,Thermometers ,Endoplasmic reticulum ,Temperature ,Nanoparticle ,Biology ,biology.organism_classification ,Endoplasmic Reticulum ,Fluorescence ,Small molecule ,Article ,HeLa ,Biochemistry ,Thermometer ,Organelle ,Biophysics ,Humans ,Nanoparticles ,Intracellular ,Fluorescent Dyes ,HeLa Cells - Abstract
The dynamics of cellular heat production and propagation remains elusive at a subcellular level. Here we report the first small molecule fluorescent thermometer selectively targeting the endoplasmic reticulum (ER thermo yellow), with the highest sensitivity reported so far (3.9%/°C). Unlike nanoparticle thermometers, ER thermo yellow stains the target organelle evenly without the commonly encountered problem of aggregation and successfully demonstrates the ability to monitor intracellular temperature gradients generated by external heat sources in various cell types. We further confirm the ability of ER thermo yellow to monitor heat production by intracellular Ca2+ changes in HeLa cells. Our thermometer anchored at nearly-zero distance from the ER, i.e. the heat source, allowed the detection of the heat as it readily dissipated and revealed the dynamics of heat production in real time at a subcellular level.
- Published
- 2014
13. Insecticidal Activity of Lamiaceae Plant Essential Oils and Their Constituents Against Blattella germanica L. Adult.
- Author
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Hwa-Jeong Yeom, Hyo-Rim Lee, Sung-Chan Lee, Ji-Eun Lee, Seon-Mi Seo, and Il-Kwon Park
- Subjects
LAMIACEAE ,BLATTELLA germanica ,SPEARMINT - Abstract
The insecticidal activities of 13 Lamiaceae plant oils and their components against adult German cockroaches, Blattella germanica L. (Blattodea: Blattellidae), were evaluated using fumigant and contact bioassay. Among the tested oils, basil, pennyroyal, and spearmint showed the strongest insecticidal activities against adult B. germanica. Insecticidal activity of pennyroyal was 100% against male B. germanica at 1.25 mg concentration in fumigant bioassay. Basil and spearmint revealed 100% and 100% insecticidal activity against male B. germanica at 5 mg concentration, but their activities reduced to 80% and 25% at 2.5 mg concentration, respectively. In contact, toxicity bioassay, basil, pennyroyal, and spearmint oils exhibited 100%, 100%, and 98% mortality against female B. germanica at 1 mg/♀, respectively. Among the constituents identified in basil, pennyroyal, and spearmint oils, insecticidal activity of pulegone was the strongest against male and female B. germanica. [ABSTRACT FROM AUTHOR]
- Published
- 2018
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14. 댄디 워커 증후군이 동반된 증후성 신경피부멜라닌증.
- Author
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Young Kwon Koh, Jung Yeon Joo, Sung Chan Lee, and Young Il Rho
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OLDER patients ,MENINGEAL cancer ,INTRAVENOUS immunoglobulins ,NEUROCUTANEOUS disorders ,PATIENTS ,THERAPEUTICS ,HEALTH - Abstract
Neurocutaneous melanosis (NCM) is a rare nonheritable congenital phakomatosis. NCM is characterized by large or multiple (>3) congenital nevi that are associated with benign and/or malignant melanocytic tumors of the leptomeninges. Approximately 10% of symptomatic patients with NCM have associated Dandy Walker complex (DWC), which seems to have an extremely poor prognosis. We report the case of a 7 year-old patient with multiple congenital NCM associated with DWC, who experienced a transient improvement in neurological symptoms including mental status and hemiparesis after intravenous immunoglobulin (IVIG) therapy. We suggest that the administration of IVIG may play a role in the treatment of symptomatic NCM. [ABSTRACT FROM AUTHOR]
- Published
- 2016
15. Evaluation of road traffic noise abatement by vegetation treatment in a 1:10 urban scale model.
- Author
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Hyung Suk Jang, Sung Chan Lee, Jin Yong Jeon, and Jian Kang
- Subjects
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TRAFFIC noise , *ACOUSTIC transients , *NOISE , *TRANSPORTATION noise , *CITY noise - Abstract
A 1:10 scale of a street canyon and courtyard was constructed to evaluate sound propagation when various vegetation treatments including trees, shrubs, vegetated facades, and green roofs were installed in the urban environment. Noise reductions in the street canyon and courtyard were measured for both single and combined vegetation treatments. Vegetated facades mitigated the overall noise level up to 1.6 dBA in the street canyon, and greening facades were effective to reduce low frequency noise levels below 1 kHz. Trees increased the noise level at high frequency bands to some extent in the street canyon, while the noise level over 1 kHz decreased in the courtyard after installing the street trees. This is because tree crowns diffused and reflected high frequency sounds into the street canyon. Green roofs offered significant noise abatement over 1 kHz in the courtyard, while the vegetated facade was effective to reduce noise levels at low frequencies. In terms of the integrated effects of vegetation treatments, a combined vegetation treatment was less effective than the sum of single treatments in the street canyon. The maximum noise reduction observed for all combinations of vegetation treatments provided 3.4 dBA of insertion loss in the courtyard. [ABSTRACT FROM AUTHOR]
- Published
- 2015
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16. Glucagon-Secreting Alpha Cell Selective Two-Photon Fluorescent Probe TP-α: For Live Pancreatic Islet Imaging.
- Author
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Agrawalla, Bikram Keshari, Chandran, Yogeswari, Wut-Hmone Phue, Sung-Chan Lee, Yun-Mi Jeong, Si Yan Diana Wan, Nam-Young Kang, and Young-Tae Chang
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- 2015
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17. Dark to light! A new strategy for large Stokes shift dyes: coupling of a dark donor with tunable high quantum yield acceptors.
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Dongdong Su, Juwon Oh, Sung-Chan Lee, Jong Min Lim, Srikanta Sahu, Xiaotong Yu, Dongho Kim, and Young-Tae Chang
- Published
- 2014
- Full Text
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18. A Molecular Fluorescent Probe for Targeted Visualization of Temperature at the Endoplasmic Reticulum.
- Author
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Satoshi Arai, Sung-Chan Lee, Duanting Zhai, Suzuki, Madoka, and Young Tae Chang
- Subjects
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ENDOPLASMIC reticulum , *THERMOMETERS , *ORGANELLES , *FLUORESCENT probes , *HEAT production (Biology) - Abstract
The dynamics of cellular heat production and propagation remains elusive at a subcellular level. Here we report the first small molecule fluorescent thermometer selectively targeting the endoplasmic reticulum (ER thermo yellow), with the highest sensitivity reported so far (3.9%/°C). Unlike nanoparticle thermometers, ER thermo yellow stains the target organelle evenly without the commonly encountered problem of aggregation, and successfully demonstrates the ability to monitor intracellular temperature gradients generated by external heat sources in various cell types. We further confirm the ability of ER thermo yellow to monitor heat production by intracellular Ca2+ changes in HeLa cells. Our thermometer anchored at nearly-zero distance from the ER, i.e. the heat source, allowed the detection of the heat as it readily dissipated, and revealed the dynamics of heat production in real time at a subcellular level. [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
- View/download PDF
19. A Macrophage-Specific Fluorescent Probe for Intraoperative Lymph Node Staging.
- Author
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Jung Sun Yoo, Sung-Chan Lee, Zhi Yen Jow, Pamela Yun Xiang Koh, and Young-Tae Chang
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LYMPH nodes , *LYMPHATICS , *GERMINAL centers , *FLUORESCENT probes , *FLUOROPHORES - Abstract
Successful identification of nodal metastases in patients with cancer is crucial to prescribe suitable treatment regimens that can improve recurrence-free survival. Although some new imaging technologies for nodal staging have been developed, such as nanoparticle-enhanced MRI and quantum-dot--based fluorescence imaging, sound technologies for intraoperative differentiation of metastatic and inflamed lymph nodes remain lacking. In this study, we illustrate the feasibility of using a macrophage-specific fluorescent probe (MFP) to visualize sentinel lymph nodes during surgery, highlighting abnormalities related to inflammation and tumor infiltration with signal enhancement and reduction methods using this technology. MFP was identified by high-throughput screening of fluorescent small-molecule libraries synthesized with a diversity-oriented approach. It selectively visualized monocyte and macrophage cell populations in vitro, by live-cell imaging and flow cytometry, as well as in vivo, for imaging-guided surgery. Collectively, this study provides preclinical proof of concept for an intraoperative imaging platform to accurately assess lymph node status, eliminating the need for invasive nodal dissections that can contribute to complications of cancer therapy. [ABSTRACT FROM AUTHOR]
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- 2014
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20. The Development of Novel Near-Infrared (NIR) Tetraarylazadipyrromethene Fluorescent Dyes.
- Author
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Sung-Chan Lee, Duanting Zhai, Mukherjee, Parag, and Young-Tae Chang
- Subjects
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ACETYL group , *BROMIDES , *NEAR infrared spectroscopy , *DEAMINATION , *AROMATIC amines , *AROMATIC compounds - Abstract
Novel structures of an near-infrared (NIR) tetraarylazadipyrromethene (aza-BODIPY) series have been prepared. We designed the core structure containing two amido groups at the para-position of the aromatic rings. The amido group was incorporated to secure insensitivity to pH and to ensure a bathochromic shift to the NIR region. Forty members of aza-BODIPY compounds were synthesized by substitution of the acetyl group with commercial amines on the alpha bromide. The physicochemical properties and photostability were investigated and the fluorescence emission maxima (745~755 nm) were found to be in the near infrared (NIR) range of fluorescence. [ABSTRACT FROM AUTHOR]
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- 2013
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21. Synthesis of a Novel BODIPY Library and Its Application in the Discovery of a Fructose Sensor.
- Author
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Zhai, Duanting, Sung-Chan Lee, Vendrell, Marc, Leong, Lai Peng, and Chang, Young-Tae
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ALDEHYDES , *ORGANIC compounds , *FRUCTOSE , *BEVERAGES , *DETECTORS - Abstract
We prepared a new library of 160 compounds by conjugation of a BODIPY core to a collection of aldehydes. This bbrary was screened against 52 biologic.!Ily relevant analytes and we identified one fluorescent sensor of fructose (Fructose Orange). Fructose Orange showed a 24-fold fluorescence increase upon recognition of fructose and an outstanding selectivity among 24 different saccharides. NMR 4 studies confirmed that five different binding interactions were formed between the sensor and fructose. Furthermore, Fructose Orange was applied to the quantification of fructose in soft drinks, being the most selective fluorescent sensor for fructose reported to date. [ABSTRACT FROM AUTHOR]
- Published
- 2012
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22. Practical Solid-Phase Parallel Synthesis of 5-2-Oxopiperazines via N-Acyliminium Ion Cyclization.
- Author
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Sung-Chan Lee and Seung Bum Park
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ORGANIC synthesis , *RING formation (Chemistry) , *ASYMMETRIC synthesis , *PIPERAZINE - Abstract
A practical solid-phase strategy for the synthesis of 5-2-oxopiperazines via N-acyliminium ion cyclization has been developed. A key step in the library synthesis is tandem acidolytic cleavage with subsequent in situ iminium formation, followed by stable enamide transformation. This approach is exemplified by the preparation of a 192-member pilot library using bromoacetal resins without further purification. [ABSTRACT FROM AUTHOR]
- Published
- 2007
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23. First Report of Myrothecium roridum Causing Leaf and Stem Rot Disease on Peperomia quadrangularis in Korea.
- Author
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Kyung-Sook Han, Seung-Kook Choi, Hyeong-Hwan Kim, Sung-Chan Lee, Jong-Han Park, Myoung-Rae Cho, and Mi-Jeong Park
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MYROTHECIUM ,PEPEROMIA ,PLANT diseases ,SEQUENCE analysis ,NUCLEIC acid isolation methods ,RECOMBINANT DNA - Abstract
In 2010, symptoms of leaf and stem rot were observed on potted plants (Peperomia quadrangularis) in a greenhouse in Yongin, Korea. The causative pathogen was identified as Myrothecium roridum based on morphological data, internal transcribed spacer sequence analysis, and pathogenicity test. To our knowledge, this is the first report of M. roridum causing leaf and stem rot disease on R quadrangularis in Korea and elsewhere worldwide. [ABSTRACT FROM AUTHOR]
- Published
- 2014
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24. Novel application of LeuckartâWallach reaction for synthesis of tetrahydro-1,4-benzodiazepin-5-ones library.
- Author
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Sung-Chan Lee and Seung Bum Park
- Subjects
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BENZODIAZEPINES , *LEUCKART reaction , *SOLID-phase synthesis , *ORGANIC chemistry - Abstract
A novel and efficient strategy has been developed to synthesize privileged tetrahydro-1,4-benzodiazepines with excellent yields and purities; this synthetic pathway was established by the revitalization of the LeuckartâWallach (LW) reaction via solid-phase synthesis. [ABSTRACT FROM AUTHOR]
- Published
- 2007
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- View/download PDF
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