249 results on '"Kang Min, Lee"'
Search Results
52. Depth and combined infection is important predictor of lower extremity amputations in hospitalized diabetic foot ulcer patients
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Jae-Seung Yun, Yoon-Goo Kang, Sung Shim Cho, Seung Hyun Ko, Sang Hoon Lee, Jung Min Lee, Seon-Ah Cha, Seokyung Woo, Yu-Bae Ahn, Eun-Gyo Jeong, Yoon-Jung Kim, and Kang-Min Lee
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Adult ,Male ,medicine.medical_specialty ,medicine.medical_treatment ,030209 endocrinology & metabolism ,Type 2 diabetes ,Amputation, Surgical ,03 medical and health sciences ,Diabetes mellitus ,0302 clinical medicine ,Internal medicine ,medicine ,Humans ,Endocrinology-Metabolism ,030212 general & internal medicine ,Amputation ,Ulcer ,Aged ,Retrospective Studies ,Aged, 80 and over ,business.industry ,Medical record ,Odds ratio ,Emergency department ,Middle Aged ,Prognosis ,medicine.disease ,Diabetic foot ,Diabetic Foot ,Surgery ,Hospitalization ,Diabetic foot ulcer ,Diabetes Mellitus, Type 2 ,Original Article ,Female ,business - Abstract
Background/aims As the prevalence of diabetes mellitus and its complications increase rapidly, diabetic foot ulcers (DFUs), which are a major diabetic complication, are expected to increase. For prevention and effective treatment, it is important to understand the clinical course of DFUs. The aim of this study was to investigate the natural course and predictors of amputation in patients with DFUs who required hospitalization. Methods A total of 209 patients with type 2 diabetes, aged 30 to 85 years, who visited emergency department or needed hospitalization due to DFUs were consecutively enrolled from May 2012 to January 2016, by retrospective medical record review. The main outcome was lower extremity amputation (LEA). Results Among 192 patients who completed follow-up, 113 patients (58.9%) required LEAs. Compared to patients without amputation, baseline levels of white blood cell counts and C-reactive protein were higher in patients with amputation. In addition, bone and joint involvement was more frequently observed in patients with amputation. Multivariable regression analysis revealed that combined infection (odds ratio [OR], 11.39; 95% confidence interval [CI], 2.55 to 50.93; p = 0.001) and bone or joint involvement (OR, 3.74; 95% CI, 1.10 to 12.70; p = 0.035) were significantly associated with an increased risk of LEA. Conclusion The depth of the wound and combined infection of DFU, rather than the extent of the wound, were significant prognostic factors of LEAs in patients with type 2 diabetes.
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- 2018
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53. Development of a Dual-arm Service Robot Using Stereo Vision and 6-Axis Manipulators
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Kang-Min Lee, San-Ma-Ro Na, Chibum Lee, Jae-Hoon Park, and Ki-Won Ann
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Service robot ,Stereopsis ,Inverse kinematics ,business.industry ,Computer science ,Computer vision ,Development (differential geometry) ,Artificial intelligence ,DUAL (cognitive architecture) ,business - Published
- 2018
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54. High-Responsivity Deep-Ultraviolet-Selective Photodetectors Using Ultrathin Gallium Oxide Films
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Sun Kyung Kim, Seung-Hyun Lee, Hae Jun Jung, Kang Min Lee, Sang Woon Lee, Soo Bin Kim, Yoon Jong Moon, Myung Su Seo, and Sung Min Kim
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Diffraction ,Materials science ,business.industry ,Band gap ,Photodetector ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,medicine.disease_cause ,01 natural sciences ,Atomic and Molecular Physics, and Optics ,0104 chemical sciences ,Electronic, Optical and Magnetic Materials ,Amorphous solid ,Micrometre ,Atomic layer deposition ,Responsivity ,Optics ,medicine ,Optoelectronics ,Electrical and Electronic Engineering ,0210 nano-technology ,business ,Ultraviolet ,Biotechnology - Abstract
Wavelength-selective photodetectors responding to deep-ultraviolet (DUV) wavelengths (λ = 200–300 nm) are drawing significant interest in diverse sensing applications, ranging from micrometer biological molecules to massive military missiles. However, most DUV photodetectors developed thus far have suffered from long response times, low sensitivity, and high processing temperatures, impeding their practical use. Here, we report fast, high-responsivity, and general-substrate-compatible DUV photodetectors based on ultrathin (3–50 nm) amorphous gallium oxide (GaOX) films grown by low-temperature (∼
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- 2017
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55. SH003-induced G1 phase cell cycle arrest induces apoptosis in HeLa cervical cancer cells
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Kangwook Lee, Seong-Gyu Ko, Youn Kyung Choi, Kang Min Lee, Yu Jeong Choi, and Hye Sook Seo
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0301 basic medicine ,Cancer Research ,Cell Survival ,Uterine Cervical Neoplasms ,Apoptosis ,Trichosanthes ,Biology ,medicine.disease_cause ,Biochemistry ,HeLa ,03 medical and health sciences ,0302 clinical medicine ,Genetics ,medicine ,Humans ,Molecular Biology ,Angelica ,Cell Proliferation ,Membrane Potential, Mitochondrial ,Oncogene ,Plant Extracts ,Cell growth ,Cancer ,Astragalus Plant ,Cell cycle ,medicine.disease ,biology.organism_classification ,Antineoplastic Agents, Phytogenic ,G1 Phase Cell Cycle Checkpoints ,Mitochondria ,Cell biology ,030104 developmental biology ,Oncology ,030220 oncology & carcinogenesis ,Cancer research ,Molecular Medicine ,Female ,Reactive Oxygen Species ,Carcinogenesis ,A431 cells ,Biomarkers ,HeLa Cells - Abstract
Cervical cancer is a prevalent disease that may lead to mortality in women. In spite of the development of common therapeutic agents to treat cancer, there are several limitations of their use owing to side effects and drug resistance, which may induce cancer recurrence. The anticancer effects of the new herbal mixture SH003 (comprising Astragalus membranaceus, Angelica gigas and Trichosanthes kirilowii Maximowicz) have been examined in various types of cancer. Thus, the present study hypothesized that SH003 may be an effective treatment for cervical cancer. SH003 treatment inhibited the growth of HeLa cells, whereas it did not affect the growth of rat intestinal epithelial cells. In addition, SH003 treatment increased the expression of apoptosis‑related proteins and promoted apoptotic cell death in HeLa cells. SH003 treatment also led to G1 phase arrest in HeLa cells. Furthermore, SH003 treatment induced the production of reactive oxygen species (ROS); however, ROS production did not appear to be related to SH003‑mediated apoptosis. Results from the present study indicated that the SH003‑induced inhibition of HeLa cell growth may be mediated through G1 phase arrest and extrinsic apoptosis, suggested that SH003 may be a potential treatment for cervical cancer.
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- 2017
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56. Methyl Red Decolorization Efficiency of a Korea Strain of Aspergillus sp. Immobilized into Different Polymeric Matrices
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Kang-Min Lee, Beom-Su Kim, and Mohamed Blaghen
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Aspergillus ,Chromatography ,biology ,Strain (chemistry) ,Ecological Modeling ,Polymeric matrix ,biology.organism_classification ,Pollution ,Fungal biomass ,chemistry.chemical_compound ,chemistry ,Wastewater ,Methyl red ,Environmental Chemistry ,Sewage treatment ,Waste Management and Disposal ,Effluent ,Water Science and Technology - Abstract
Intensive research studies have revealed that fungal decolorization of dye wastewater is a promising replacement for the current process of dye wastewater decolorization. The authors isolated an Aspergillus sp. from the effluent of a textile industry area in Korea and assessed the effects of a variety of operational parameters on the decolorization of methyl red (MR) by this strain of Aspergillus sp. This Aspergillus sp. was then immobilized by entrapment in several polymeric matrices and the effects of operational conditions on MR decolorization were investigated again. The optimal decolorization activity of this Aspergillus sp. was observed in 1% glucose at a temperature of 37 °C and pH of 6.0. Furthermore, stable decolorization efficiency was observed when fungal biomass was immobilized into alginate gel during repeated batch experiment. These results suggest that the Aspergillus sp. isolated in Korea could be used to treat industrial wastewaters containing MR dye.
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- 2017
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57. A simple hypochlorous acid signaling probe based on resorufin carbonodithioate and its biological application
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Suk-Kyu Chang, Tae Jung Park, Kang Min Lee, Yu Jeong Lee, Myung Gil Choi, and Kyoung Yeol Park
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Double bond ,Hypochlorous acid ,Cell Survival ,Metal ions in aqueous solution ,Iodide ,02 engineering and technology ,Photochemistry ,01 natural sciences ,Biochemistry ,Analytical Chemistry ,Hydrolysis ,chemistry.chemical_compound ,Mice ,Bromide ,Limit of Detection ,Oxazines ,Electrochemistry ,Environmental Chemistry ,Animals ,Humans ,Spectroscopy ,Fluorescent Dyes ,chemistry.chemical_classification ,Microscopy, Confocal ,010401 analytical chemistry ,021001 nanoscience & nanotechnology ,Fluorescence ,0104 chemical sciences ,Hypochlorous Acid ,RAW 264.7 Cells ,chemistry ,Microscopy, Fluorescence ,Colorimetry ,0210 nano-technology ,Derivative (chemistry) ,HeLa Cells - Abstract
A novel hypochlorous-acid-selective signaling probe based on the carbonodithioate derivative of resorufin (RT-1) was developed. Probe RT-1 showed prominent colorimetric and turn-on type fluorescence signaling behavior exclusively toward hypochlorous acid, induced by oxidative hydrolysis, to regenerate resorufin dye. Hypochlorous acid signaling was not affected by the presence of common metal ions and anions as background, except for the redox active bromide and iodide anions. The detection limit of RT-1 for hypochlorous acid was found to be 2.18 × 10-9 M (0.11 ppb), and the signaling was completed within 3 min. It was also confirmed that hypochlorous acid signaling by the carbonodithioate-based probe RT-1 was superior to that of the closely related carbonothioate derivative RT-2. This was rationalized by density functional theory calculations, which demonstrated that the C[double bond, length as m-dash]S sulfur atom of the former is more negatively charged than that of the latter. Finally, as a biological application of the probe, visualization of hypochlorous acid in RAW 264.7 murine macrophages and HeLa cells was successfully conducted to detect the cellular response to hypochlorous acid.
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- 2019
58. Atomic Layer Deposition of High-k Films on Graphene Surface
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Hyeok Jae Lee, Sang Woon Lee, and Kang Min Lee
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Surface (mathematics) ,Atomic layer deposition ,Materials science ,Chemical engineering ,Graphene ,law ,law.invention ,High-κ dielectric - Published
- 2019
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59. Amorphous Gallium Oxide Thin Film Grown by Atomic Layer Deposition for High-Performance and Flexible Deep-Ultraviolet Photodetector
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Hyeok Jae Lee, Sang Woon Lee, Se Eun Kim, and Kang Min Lee
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Atomic layer deposition ,Gallium oxide ,Materials science ,business.industry ,medicine ,Photodetector ,Optoelectronics ,Thin film ,business ,medicine.disease_cause ,Ultraviolet ,Amorphous solid - Published
- 2019
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60. Fluorometric analysis of chlorite via oxidation of 9-anthracenecarboxaldehyde
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Sangdoo Ahn, Myung Gil Choi, Suk-Kyu Chang, Jae Hoon Yoo, and Kang Min Lee
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Detection limit ,chemistry.chemical_classification ,Anthracene ,General Chemical Engineering ,Metal ions in aqueous solution ,Carboxylic acid ,General Physics and Astronomy ,Hypochlorite ,02 engineering and technology ,General Chemistry ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Photochemistry ,01 natural sciences ,Fluorescence ,0104 chemical sciences ,chemistry.chemical_compound ,chemistry ,Tap water ,0210 nano-technology ,Chlorite - Abstract
We investigated a simple fluorescence signaling method for the convenient analysis of a practical oxidant—chlorite—via the oxidation of 9-anthracenecarboxaldehyde to the corresponding carboxylic acid. 9-Anthracenecarboxaldehyde exhibited a marked ratiometric fluorescence signaling toward chlorite through manipulating its aggregation-induced emission property. The probe showed high chlorite-selectivity over other oxychlorine species as well as common metal ions, anions, and oxidants. Interference from a closely related oxidant, hypochlorite, was efficiently removed using DMSO as a scavenger. The proposed probe also exhibited a prominent ratiometric response through changes in UV–vis absorption behavior. Among the tested aromatic aldehydes (naphthaldehydes, anthracenecarboxaldehyde, and pyrenecarboxaldehyde), anthracene-based carboxaldehyde exhibited the most pronounced signaling contrast and the fastest signaling speed. The detection limit of chlorite determination was found to be 1.1 × 10–7 M. Exploitation of the probe for the convenient analysis of chlorite in tap water via a recovery test was conducted.
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- 2021
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61. Baseline-Corrected QT (QTc) Interval Is Associated with Prolongation of QTc during Severe Hypoglycemia in Patients with Type 2 Diabetes Mellitus
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Seung Hyun Ko, Ki Ho Song, Kang-Min Lee, Jae Seung Yun, Yoon-Goo Kang, Tae Seok Lim, Yong-Moon Park, Seon-Ah Cha, Yu Bae Ahn, and Ki Dong Yoo
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QT interval ,medicine.medical_specialty ,congenital, hereditary, and neonatal diseases and abnormalities ,Complications ,Endocrinology, Diabetes and Metabolism ,030209 endocrinology & metabolism ,lcsh:Diseases of the endocrine glands. Clinical endocrinology ,03 medical and health sciences ,0302 clinical medicine ,Diabetes mellitus ,Internal medicine ,Medicine ,030212 general & internal medicine ,cardiovascular diseases ,Severe hypoglycemia ,lcsh:RC648-665 ,medicine.diagnostic_test ,business.industry ,Incidence (epidemiology) ,Prolongation ,Type 2 Diabetes Mellitus ,Diabetes mellitus, type 2 ,Odds ratio ,medicine.disease ,Confidence interval ,Cardiology ,cardiovascular system ,Original Article ,business ,Electrocardiography ,circulatory and respiratory physiology - Abstract
BACKGROUND We investigated an association between baseline heart rate-corrected QT (QTc) interval before severe hypoglycemia (SH) and prolongation of QTc interval during SH in patients with type 2 diabetes mellitus (T2DM). METHODS Between January 2004 and June 2014, 208 patients with T2DM, who visited the emergency department because of SH and underwent standard 12-lead electrocardiography within the 6-month period before SH were consecutively enrolled. The QTc interval was analyzed during the incidence of SH, and 6 months before and after SH. QTc intervals of 450 ms or longer in men and 460 ms or longer in women were considered abnormally prolonged. RESULTS The mean age and diabetes duration were 68.1±12.1 and 14.1±10.1 years, respectively. The mean QTc intervals at baseline and SH episodes were 433±33 and 460±33 ms, respectively (P
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- 2016
62. SH003 suppresses breast cancer growth by accumulating p62 in autolysosomes
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Yee Jin Yun, Seong-Gyu Ko, Sung-Gook Cho, Youn Kyung Choi, Yu-Jeong Choi, Hye Hyun Yoo, Yong Cheol Shin, Kangwook Lee, and Kang Min Lee
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0301 basic medicine ,autophagy ,Programmed cell death ,Cellular homeostasis ,Metastasis ,03 medical and health sciences ,breast cancer ,0302 clinical medicine ,Breast cancer ,medicine ,Traditional medicine ,business.industry ,p62 ,Autophagy ,apoptosis ,Cancer ,medicine.disease ,Metastatic breast cancer ,030104 developmental biology ,Oncology ,SH003 ,030220 oncology & carcinogenesis ,Cancer cell ,Cancer research ,business ,Research Paper - Abstract
// Youn Kyung Choi 1, * , Sung-Gook Cho 2, * , Yu-Jeong Choi 3 , Yee Jin Yun 3 , Kang Min Lee 4 , Kangwook Lee 4 , Hye-Hyun Yoo 5 , Yong Cheol Shin 6 and Seong-Gyu Ko 6 1 Jeju International Marine Science Center for Research and Education, Korea Institute of Ocean Science and Technology (KIOST), Jeju, 695-975, Korea 2 Department of Biotechnology, Korea National University of Transportation, Chungbuk, 368-701, Korea 3 Department of Cancer Preventive Material Development, Graduate School, Kyung Hee University, Seoul, 130-701, Korea 4 Department of Science in Korean Medicine, Graduate School, Kyung Hee University, Seoul, 130-701, Korea 5 Institute of Pharmaceutical Science and Technology and Collage of Pharmacy, Hanyang University, Gyonggi, 426-791, Korea 6 Laboratory of Clinical Biology and Pharmacogenomics, Department of Preventive Medicine, College of Korean Medicine, Kyung Hee University, Seoul, 130-701, Korea * These authors contributed equally to this work Correspondence to: Seong-Gyu Ko, email: epiko@khu.ac.kr Keywords: SH003, breast cancer, autophagy, apoptosis, p62 Received: October 15, 2015 Accepted: July 27, 2016 Published: August 19, 2016 ABSTRACT Drug markets revisits herbal medicines, as historical usages address their therapeutic efficacies with less adverse effects. Moreover, herbal medicines save both cost and time in development. SH003, a modified version of traditional herbal medicine extracted from Astragalus membranaceus (Am), Angelica gigas (Ag), and Trichosanthes Kirilowii Maximowicz (Tk) with 1:1:1 ratio (w/w) has been revealed to inhibit tumor growth and metastasis on highly metastatic breast cancer cells, both in vivo and in vitro with no toxicity. Meanwhile, autophagy is imperative for maintenance cellular homeostasis, thereby playing critical roles in cancer progression. Inhibition of autophagy by pharmacological agents induces apoptotic cell death in cancer cells, resulting in cancer treatment. In this study, we demonstrate that SH003-induced autophagy via inhibiting STAT3 and mTOR results in an induction of lysosomal p62/SQSTM1 accumulation-mediated reactive oxygen species (ROS) generation and attenuates tumor growth. SH003 induced autophagosome and autolysosome formation by inhibiting activation of STAT3- and mTOR-mediated signaling pathways. However, SH003 blocked autophagy-mediated p62/SQSTM1 degradation through reducing of lysosomal proteases, Cathepsins, resulting in accumulation of p62/SQSTM1 in the lysosome. The accumulation of p62/SQSTM1 caused the increase of ROS, which resulted in the induction of apoptotic cell death. Therefore, we conclude that SH003 suppresses breast cancer growth by inducing autophagy. In addition, SH003-induced p62/SQSTM1 could function as an important mediator for ROS generation-dependent cell death suggesting that SH003 may be useful for treating breast cancer.
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- 2016
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63. A Study of the Taking Curvilinear Approach between Perceived Ethical Organization Culture and Unethical Pro-organizational Behavior: Focused on the Moderating Effect of Organizational Identification
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Sang Gil Jeon and Kang Min Lee
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business.industry ,Organizational behavior ,Organizational identification ,Organizational culture ,General Medicine ,Public relations ,business ,Psychology ,Social psychology - Published
- 2016
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64. Making a Perfect Probation System in Korean Criminal Act?
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Kang-Min Lee
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Law ,Political science ,Suspended sentence ,General Medicine - Published
- 2016
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65. Spontaneous Hepatic Infarction in a Patient with Gallbladder Cancer
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Yun Hwa Jung, Jung Won Heo, Kang Min Lee, In Sook Woo, Seo Kyung Woo, and Hannah Joung
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medicine.medical_specialty ,Case Report ,Gall bladder cancer ,lcsh:RC254-282 ,Gastroenterology ,03 medical and health sciences ,0302 clinical medicine ,Internal medicine ,medicine ,In patient ,cardiovascular diseases ,Gallbladder cancer ,Hepatic infarction ,business.industry ,Cancer ,lcsh:Neoplasms. Tumors. Oncology. Including cancer and carcinogens ,medicine.disease ,Biliary cancer ,Oncology ,030220 oncology & carcinogenesis ,cardiovascular system ,Cardiology ,Etiology ,030211 gastroenterology & hepatology ,Complication ,business ,Rare disease - Abstract
Hepatic infarction is known as a rare disease entity in nontransplant patients. Although a few cases of hepatic infarction have been reported to be linked with invasive procedures, trauma, and hypercoagulability, a case of spontaneous hepatic infarction in a nontransplanted patient has hardly ever been reported. However, many clinical situations of patients with cancer, in particular biliary cancer, can predispose nontransplant patients to hepatic infarction. Besides, the clinical outcome of hepatic infarction in patients with cancer can be worse than in patients with other etiologies. As for treatment, anticoagulation treatment is usually recommended. However, because of its multifactorial etiology and combined complications, treatment of hepatic infarction is difficult and not simple. Herein, we report a case of fatal hepatic infarction that occurred spontaneously during the course of treatment in a patient with gallbladder cancer. Hepatic infarction should be considered as a possible fatal complication in patients during treatment of biliary malignancies.
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- 2016
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66. Establishment of the East-Asian Translation of Architecture and its Influence
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Kang-Min Lee
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Engineering ,business.industry ,Etymology ,Art history ,East Asia ,Architecture ,business ,Classics - Published
- 2016
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67. DSGOST inhibits tumor growth by blocking VEGF/VEGFR2-activated angiogenesis
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Kang Min Lee, Kangwook Lee, Seong-Gyu Ko, Min Kyoung Kim, Hyeong Sim Choi, Sung-Gook Cho, and Yong Cheol Shin
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0301 basic medicine ,Vascular Endothelial Growth Factor A ,tumor ,Angiogenesis ,VEGF receptors ,Mice, Nude ,Angiogenesis Inhibitors ,03 medical and health sciences ,angiogenesis ,0302 clinical medicine ,In vivo ,Pancreatic tumor ,Cell Movement ,Cell Line, Tumor ,Human Umbilical Vein Endothelial Cells ,Medicine ,Animals ,Humans ,Viability assay ,Cells, Cultured ,Mice, Inbred BALB C ,Traditional medicine ,biology ,Neovascularization, Pathologic ,business.industry ,NF-kappa B ,Cancer ,medicine.disease ,VEGF ,Vascular Endothelial Growth Factor Receptor-2 ,Xenograft Model Antitumor Assays ,In vitro ,Tumor Burden ,Pancreatic Neoplasms ,030104 developmental biology ,medicine.anatomical_structure ,DSGOST ,Oncology ,030220 oncology & carcinogenesis ,herbal medicine ,Cancer research ,biology.protein ,business ,Blood vessel ,Research Paper ,Drugs, Chinese Herbal ,Signal Transduction - Abstract
Tumor growth requires a process called angiogenesis, a new blood vessel formation from pre-existing vessels, as newly formed vessels provide tumor cells with oxygen and nutrition. Danggui-Sayuk-Ga-Osuyu-Saenggang-Tang (DSGOST), one of traditional Chinese medicines, has been widely used in treatment of vessel diseases including Raynaud's syndrome in Northeast Asian countries including China, Japan and Korea. Therefore, we hypothesized that DSGOST might inhibit tumor growth by targeting newly formed vessels on the basis of its historical prescription. Here, we demonstrate that DSGOST inhibits tumor growth by inhibiting VEGF-induced angiogenesis. DSGOST inhibited VEGF-induced angiogenic abilities of endothelial cells in vitro and in vivo, which resulted from its inhibition of VEGF/VEGFR2 interaction. Furthermore, DSGOST attenuated pancreatic tumor growth in vivo by reducing angiogenic vessel numbers, while not affecting pancreatic tumor cell viability. Thus, our data conclude that DSGOST inhibits VEGF-induced tumor angiogenesis, suggesting a new indication for DSGOST in treatment of cancer.
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- 2016
68. Colorimetric and fluorescence analysis of percarbonate and oxygen bleach by perhydrolysis of resorufin ester
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Suk-Kyu Chang, Jae Hoon Yoo, Kang Min Lee, Myung Gil Choi, Sangdoo Ahn, Na Young Kim, and Ka Young Park
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Detection limit ,Bleach ,Process Chemistry and Technology ,General Chemical Engineering ,Metal ions in aqueous solution ,chemistry.chemical_element ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Combinatorial chemistry ,Oxygen ,Fluorescence ,0104 chemical sciences ,chemistry.chemical_compound ,chemistry ,0210 nano-technology ,Hydrogen peroxide ,Spontaneous hydrolysis - Abstract
Percarbonate is an important oxidant that is widely used in industrial applications and daily life. In this study, a simple colorimetric and fluorescence method for percarbonate determination using resorufin-based probe 1, carrying a pivaloyl protection group as a signaling switch, was developed. Probe 1 exhibited selective and sensitive signaling behavior for percarbonate via perhydrolysis of the pivaloyl group by hydrogen peroxide that was produced from percarbonate, in the presence of commonly encountered metal ions and anions. Among the esters tested as signaling switches, pivalate was optimal owing to its resistance to spontaneous hydrolysis and high signaling speed under the employed conditions. The detection limit for percarbonate was estimated to be 0.45 μM. The probe was applied to the analysis of percarbonate in domestic bleach using a scanner as a field-oriented signal-capturing device.
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- 2021
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69. Colorimetric analysis of malononitrile via the formation of a novel NBD-based CH-acidic dye
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Na Yeong Kim, Sungguan Hong, Myung Gil Choi, Suk-Kyu Chang, and Kang Min Lee
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Detection limit ,chemistry.chemical_classification ,Sulfide ,Chemistry ,Process Chemistry and Technology ,General Chemical Engineering ,Metal ions in aqueous solution ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Photochemistry ,01 natural sciences ,Scavenger (chemistry) ,0104 chemical sciences ,chemistry.chemical_compound ,Nucleophilic substitution ,0210 nano-technology ,Colorimetric analysis ,Masking agent ,Malononitrile - Abstract
Malononitrile is a key starting material used in synthetic organic, medical, and industrial chemistry, but it is also a notorious cyanogenic toxicant. However, selective and sensitive analytical methods for this key chemical are rare. In this research, a novel reaction-based colorimetric signaling probe for the selective analysis of malononitrile via the SNAr-type nucleophilic substitution reaction of an NBD-based phenyl selenoether was investigated. The probe exhibited a pronounced colorimetric response, with a color change from yellow to violet due to its CH-acidity. The interference of sulfide ions and several transition metal ions was effectively circumvented with the use of copper foil as a sulfide scavenger and EDTA as a masking agent for the metal ions. The detection limit of the probe for malononitrile was found to be 264 nM. It was also demonstrated that this convenient colorimetric analysis of malononitrile in chemical and industrial applications using the probe can be conducted with an office scanner.
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- 2020
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70. Blue-colored dyes featuring a diketopyrrolopyrrole spacer for translucent dye-sensitized solar cells
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Jongin Hong, Dong suk Lim, Alvien Ghifari, Yongseok Jun, Kyungah Choi, Da Heon Park, Yohan Ko, Hyeon-Jeong Suk, Dini Hayati, and Kang Min Lee
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Materials science ,Process Chemistry and Technology ,General Chemical Engineering ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Photochemistry ,Electrochemistry ,01 natural sciences ,0104 chemical sciences ,Dye-sensitized solar cell ,chemistry.chemical_compound ,Blue colored ,chemistry ,Yield (chemistry) ,0210 nano-technology ,Dimethylamine - Abstract
We report the facile synthesis of blue-colored dyes featuring a diketopyrrolopyrrole (DPP) spacer with dimethylamine and bis(4-dibuotxylphenyl)-phenyl-amine as donor residues (CSD-08 and CSD-09), their spectroscopic, electrochemical and colorific properties, and their application to translucent dye-sensitized solar cells (DSSCs). In the DSSCs fabricated with 5 μm-thick TiO2 photoanodes, CSD-08 and CSD-09 yield power-conversion-efficiencies of 3.43% and 3.62%, respectively, under simulated one sun illumination.
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- 2020
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71. Organotypic slice cultures of pancreatic ductal adenocarcinoma preserve the tumor microenvironment and provide a platform for drug response
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Jae Hyuck Chang, Kang Min Lee, Il Young Park, Young Chul Yoon, Won Sun Lee, Jeana Kim, and Chae Yoon Lim
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0301 basic medicine ,Male ,Stromal cell ,Endocrinology, Diabetes and Metabolism ,CD3 ,Antineoplastic Agents ,Apoptosis ,03 medical and health sciences ,0302 clinical medicine ,Organ Culture Techniques ,Pancreatic cancer ,Cell Line, Tumor ,Biomarkers, Tumor ,Tumor Microenvironment ,Cytotoxic T cell ,Medicine ,Animals ,Humans ,Aged ,Cell Proliferation ,Tumor microenvironment ,Hepatology ,biology ,business.industry ,Gastroenterology ,Middle Aged ,medicine.disease ,Immunohistochemistry ,Xenograft Model Antitumor Assays ,Pancreatic Neoplasms ,030104 developmental biology ,Cell culture ,Drug Resistance, Neoplasm ,030220 oncology & carcinogenesis ,Cancer research ,biology.protein ,Female ,business ,Carcinoma, Pancreatic Ductal - Abstract
Background /Objective: The conventional models currently used to evaluate various anti-tumor therapeutic agents are not sufficient for representing human pancreatic ductal adenocarcinoma (PDA), which has a unique tumor microenvironment. We aimed to produce an organotypic slice culture model from human PDA that resembles the in vivo situation and to evaluate the responses of PDA slices to established cytotoxic drugs. Methods PDA tissues were obtained from 10 patients who underwent pancreatic resection. The tissues were sliced by a vibratome, and the tumor slices were then cultured. The viability of tumor slices during slice culture was evaluated using H&E and immunohistochemical staining, and stromal cells were demonstrated. The effects of cytotoxic drugs on PDA cell lines and slices were analyzed. Results Tumor slices maintained their surface areas and tissue viability for at least five days during culture. Preserved proliferation and apoptosis in tumor slices were observed by the expression of Ki-67 and cleaved caspase-3. Stromal cells including macrophages (CD68+ and CD163+), T cells (CD3+, CD8+, and FOXP3+), and myeloid cells (CD11b+) were present throughout the culture period. Staurosporine, gemcitabine, and cisplatin treatment of PDA cell lines and tumor slices exerted proportional cytotoxic effects in terms of MTT viability, tumor cell number, and Ki-67 and cleaved caspase-3 expression. Conclusions Organotypic human PDA slice cultures preserved their viability and tumor microenvironment for at least five days during slice culture. PDA slice culture appears to be a feasible preclinical test model to assess the response to anti-tumor agents.
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- 2018
72. A corticotrophin-releasing factor homolog sets the level of sexual motivation in female Drosophila
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Kang-Min Lee, Young-Hoon Jang, Young-Joon Kim, and Do-Hyoung Kim
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biology ,General Neuroscience ,Corticotrophin releasing factor ,Drosophila (subgenus) ,biology.organism_classification ,Cell biology - Published
- 2019
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73. A Neuronal Pathway that Controls Sperm Ejection and Storage in Female Drosophila
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Chen Zhang, Kang-Min Lee, Sekyu Choi, R. Elwyn Isaac, Ivana Daubnerová, Young-Joon Kim, and Jongkyeong Chung
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Male ,endocrine system ,medicine.medical_specialty ,Doublesex ,Neuropeptide ,Receptors, Cell Surface ,General Biochemistry, Genetics and Molecular Biology ,Animals, Genetically Modified ,Andrology ,Sexual Behavior, Animal ,Human fertilization ,Internal medicine ,Neural Pathways ,medicine ,Animals ,Drosophila Proteins ,Mating ,Sperm competition ,reproductive and urinary physiology ,Agricultural and Biological Sciences(all) ,biology ,Biochemistry, Genetics and Molecular Biology(all) ,urogenital system ,Reproduction ,Neuropeptides ,Brain ,biology.organism_classification ,Spermatozoa ,Sperm ,Drosophila melanogaster ,Endocrinology ,Fertilization ,Insect Hormones ,Sexual selection ,Female ,RNA Interference ,General Agricultural and Biological Sciences - Abstract
Summary In polyandrous females, sperm storage permits competition between sperm of different mates, and in some species females influence the relative fertilization success of competing sperm in favor of a preferred mate [1, 2]. In female Drosophila melanogaster , sperm competition is strongly influenced by the timing of sperm ejection from the uterus [3, 4]. Understanding how female behavior influences sperm competition requires knowledge of the neuronal mechanisms controlling sperm retention and storage, which is currently lacking. Here, we show that D. melanogaster females eject male ejaculates from the uterus 1–6 hr after mating with a stereotypic behavior regulated by a brain signaling pathway composed of diuretic hormone 44 (Dh44), a neuropeptide related to vertebrate corticotropin-releasing factor (CRF), and its receptor, Dh44R1. Suppression of Dh44 signals in the brain expedites sperm ejection from the uterus, resulting in marked reduction of sperm in the storage organs and decreased fecundity, whereas enhancement of Dh44 signals delays sperm expulsion. The Dh44 function was mapped to six neurons located in the pars intercerebralis of the brain together with a small subset of Dh44R1 neurons that express the sex-specific transcription factor doublesex . This study identifies a neuronal pathway by which females can control sperm retention and storage and provides new insight into how the female might exercise post-copulatory sexual selection.
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- 2015
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74. Formation of ZrO2 in coating on Mg–3 wt.%Al–1 wt.%Zn alloy via plasma electrolytic oxidation: Phase and structure of zirconia
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Dong Hyuk Shin, Young Gun Ko, Kang Min Lee, Joo Hyun Park, Yeon Sung Kim, and Hae Woong Yang
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Materials science ,Mechanical Engineering ,Inorganic chemistry ,Alloy ,Analytical chemistry ,Substrate (electronics) ,engineering.material ,Plasma electrolytic oxidation ,Condensed Matter Physics ,Nanocrystalline material ,Barrier layer ,Coating ,Mechanics of Materials ,Transmission electron microscopy ,engineering ,General Materials Science ,Layer (electronics) - Abstract
An investigation of the coating structure formed on Mg–3 wt.%Al–1 wt.%Zn alloy sample subjected to plasma electrolytic oxidation was examined by field-emission transmission electron microscopy. The plasma electrolytic oxidation process was conducted in a phosphoric acid electrolyte containing K{sub 2}ZrF{sub 6} for 600 s. Microstructural observations showed that the coating consisting of MgO, MgF{sub 2}, and ZrO{sub 2} phases was divided into three distinctive parts, the barrier, intermediate, and outer layers. Nanocrystalline MgO and MgF{sub 2} compounds were observed mainly in the barrier layer of ~ 1 μm thick near to the substrate. From the intermediate to outer layers, various ZrO{sub 2} polymorphs appeared due to the effects of the plasma arcing temperature on the phase transition of ZrO{sub 2} compounds during the plasma electrolytic oxidation process. In the outer layer, MgO compound grew in the form of a dendrite-like structure surrounded by cubic ZrO{sub 2}. - Highlights: • The barrier layer containing MgO and MgF{sub 2} was observed near to the Mg substrate. • In the intermediate layer, m-, t-, and o-ZrO{sub 2} compounds were additionally detected. • The outer layer contained MgO with the dendrite-like structure surrounded by c-ZrO{sub 2}. • The grain sizes of compounds in oxidemore » layer increased from barrier to outer layer.« less
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- 2015
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75. Novel herbal medicine LA16001 ameliorates cisplatin-induced anorexia
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Seong-Gyu Ko, Kang Min Lee, Young Cheol Shin, Sung-Gook Cho, Ji Youn Park, Hee Jae Lee, Hyo‑Jung Bahn, Gyu Ri Lee, Hyun Seok Yoon, Sang Mi Woo, and Jem Yung Kim
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Male ,STAT3 Transcription Factor ,Cancer Research ,Herbal Medicine ,media_common.quotation_subject ,Prunella vulgaris ,Appetite ,Antineoplastic Agents ,Anorexia ,Pharmacology ,Biochemistry ,Eating ,Mice ,03 medical and health sciences ,0302 clinical medicine ,Neoplasms ,Orexigenic ,Genetics ,medicine ,Animals ,Humans ,Hormone metabolism ,Adverse effect ,Molecular Biology ,media_common ,biology ,Plant Extracts ,business.industry ,Janus Kinase 1 ,biology.organism_classification ,Molecular medicine ,Hormones ,Disease Models, Animal ,Angelica gigas ,Oncology ,030220 oncology & carcinogenesis ,Molecular Medicine ,Cisplatin ,medicine.symptom ,business ,030217 neurology & neurosurgery ,Signal Transduction ,medicine.drug - Abstract
Chemotherapy frequently causes anorexia in cancer patients, which has been associated with poor disease prognosis. Several therapeutic strategies for the treatment of chemotherapy‑induced anorexia are available; however, their adverse effects limit their clinical use. Herbal medicines have a long history of use for the treatment of various diseases, including cancer, and recent research has demonstrated their safety and efficacy. In the present study, combinations of herbal medicines were designed based on traditional Korean medicine, and their effects were investigated on chemotherapy‑induced anorexia. Herbal mixtures were extracted, composed of Atractylodes japonica, Angelica gigas, Astragalus membranaceus, Lonicera japonica Thunb., Taraxacum platycarpum H. Dahlstedt and Prunella vulgaris var. asiatica (Nakai) Hara. The mixtures were termed LCBP‑Anocure‑16001‑3 (LA16001, LA16002, LA16003). A cisplatin‑induced anorexic mouse model was used to evaluate the putative effects of the extracts on chemotherapy‑induced anorexia. Treatment with LA16001 was revealed to prevent body weight loss, and all three extracts were demonstrated to improve food intake. When the molecular mechanisms underlying the orexigenic effects of LA16001 were investigated, altered expression levels of ghrelin, leptin and interleukin‑6 were revealed. Furthermore, LA16001 was reported to induce phosphorylation of Janus kinase 1 and signal transducer and activator of transcription 3. In addition, LA16001 administration increased the number of white blood cells and neutrophils. These results suggested that the herbal formula LA16001 may be able to prevent chemotherapy‑induced anorexia and may have potential as a novel therapeutic strategy for the adjuvant treatment of patients with cancer.
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- 2017
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76. Tuberatolide B Suppresses Cancer Progression by Promoting ROS-Mediated Inhibition of STAT3 Signaling
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Kang Min Lee, Min-Sun Kim, Seung-Hong Lee, Seong-Gyu Ko, Soo-Jin Heo, Bo-Ram Ye, Youn Kyung Choi, Do-Hyung Kang, Yu-Jeong Choi, and Junseong Kim
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0301 basic medicine ,Vascular Endothelial Growth Factor A ,DNA damage ,Pharmaceutical Science ,Antineoplastic Agents ,Apoptosis ,Biology ,tuberatolide B ,cancer ,STAT3 ,ROS ,Article ,Inhibitor of Apoptosis Proteins ,03 medical and health sciences ,0302 clinical medicine ,Cyclin D1 ,Cell Line, Tumor ,Drug Discovery ,Survivin ,Humans ,Phosphorylation ,Pharmacology, Toxicology and Pharmaceutics (miscellaneous) ,lcsh:QH301-705.5 ,Cell Proliferation ,A549 cell ,Cell growth ,Interleukin-6 ,Terpenes ,HCT116 Cells ,Cell biology ,030104 developmental biology ,Matrix Metalloproteinase 9 ,lcsh:Biology (General) ,A549 Cells ,030220 oncology & carcinogenesis ,biology.protein ,Cancer research ,Disease Progression ,MCF-7 Cells ,Signal transduction ,Reactive Oxygen Species ,HeLa Cells ,Signal Transduction - Abstract
Tuberatolide B (TTB, C27H34O4) is a diastereomeric meroterpenoid isolated from the Korean marine algae Sargassum macrocarpum. However, the anticancer effects of TTB remain unknown. In this study, we demonstrate that TTB inhibits tumor growth in breast, lung, colon, prostate, and cervical cancer cells. To examine the mechanism by which TTB suppresses cell growth, we determined the effect of TTB on apoptosis, ROS generation, DNA damage, and signal transduction. TTB induced ROS production in MDA-MB-231, A549, and HCT116 cells. Moreover, TTB enhanced DNA damage by inducing γH2AX foci formation and the phosphorylation of DNA damage-related proteins such as Chk2 and H2AX. Furthermore, TTB selectively inhibited STAT3 activation, which resulted in a reduction in cyclin D1, MMP-9, survivin, VEGF, and IL-6. In addition, TTB-induced ROS generation caused STAT3 inhibition, DNA damage, and apoptotic cell death. Therefore, TTB suppresses cancer progression by promoting ROS-mediated inhibition of STAT3 signaling, suggesting that TTB is useful for the treatment of cancer.
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- 2017
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77. Microstructural characteristics of oxide layers formed on Mg–9wt%Al–1wt%Zn alloy via two-step plasma electrolytic oxidation
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Dong Hyuk Shin, Kang Min Lee, and Young Gun Ko
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Materials science ,Scanning electron microscope ,Mechanical Engineering ,Metallurgy ,Metals and Alloys ,Oxide ,Electrolyte ,Substrate (electronics) ,Plasma electrolytic oxidation ,engineering.material ,Microstructure ,chemistry.chemical_compound ,Coating ,chemistry ,Chemical engineering ,Mechanics of Materials ,Materials Chemistry ,engineering ,Layer (electronics) - Abstract
A study investigated the formation and microstructural features of the oxide layer formed on Mg–9 wt%Al–1 wt%Zn alloy coated by two-step plasma electrolytic oxidation (PEO) where an acid electrolyte with K 2 ZrF 6 was used for the second PEO coating after the initial coating was done in an alkaline electrolyte. The microstructure, chemical compositions, and constituent compounds of the oxide layers were observed using scanning electron microscopy, electron probe micro-analyzer, and X-ray diffraction, respectively. The microstructural observations showed that the micropores caused by plasma discharge were formed in the oxide layers which were comprised of three different parts, namely, inner, intermediate, and outer layers from the substrate to the surface of the sample. The outer layer contained the highest concentration of Zr element whose amount decreased toward the substrate whereas the concentration of Mg element increased in the order of outer, intermediate, and inner layers. This finding suggested that the outer oxide layer was mainly comprised of ZrO 2 compound while both ZrO 2 and Mg 2 Zr 5 O 12 compounds existed together as the main compounds in the intermediate oxide layer.
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- 2014
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78. Electrospun propolis/polyurethane composite nanofibers for biomedical applications
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Jeong In Kim, Hem Raj Pant, Kang Min Lee, Hyun-Jaung Sim, and Cheol Sang Kim
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Thermogravimetric analysis ,Materials science ,Chemical Phenomena ,Cell Survival ,Polymers ,Polyurethanes ,Composite number ,Nanofibers ,Biocompatible Materials ,Bioengineering ,Propolis ,Nanocomposites ,Biomaterials ,Mice ,chemistry.chemical_compound ,3T3-L1 Cells ,Spectroscopy, Fourier Transform Infrared ,Escherichia coli ,Animals ,Composite material ,Mechanical Phenomena ,Polyurethane ,Nanocomposite ,Tissue Engineering ,Fibroblasts ,Electrospinning ,Anti-Bacterial Agents ,Microscopy, Electron ,chemistry ,Mechanics of Materials ,Nanofiber ,Adhesive ,Hydrophobic and Hydrophilic Interactions - Abstract
Tissue engineering requires functional polymeric membrane for adequate space for cell migration and attachment within the nanostructure. Therefore, biocompatible propolis loaded polyurethane (propolis/PU) nanofibers were successfully prepared using electrospinning of propolis/PU blend solution. Here, composite nanofibers were subjected to detailed analysis using electron microscopy, FT-IR spectroscopy, thermal gravimetric analysis (TGA), and mechanical properties and water contact angle measurement. FE-SEM images revealed that the composite nanofibers became point-bonded with increasing amounts of propolis in the blend due to its adhesive properties. Incorporation of small amount of propolis through PU matrix could improve the hydrophilicity and mechanical strength of the fibrous membrane. In order to assay the cytocompatibility and cell behavior on the composite scaffolds, fibroblast cells were seeded on the matrix. Results suggest that the incorporation of propolis into PU fibers could increase its cell compatibility. Moreover, composite nanofibers have effective antibacterial activity. Therefore, as-synthesized nanocomposite fibrous mat has great potentiality in wound dressing and skin tissue engineering.
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- 2014
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79. Needle-free transdermal delivery using PLGA nanoparticles: Effect of particle size, injection pressure and syringe orifice diameter
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Leonard D. Tijing, Chan Hee Park, Cheol Sang Kim, and Kang Min Lee
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Materials science ,Skin Absorption ,Nanoparticle ,Nanotechnology ,Administration, Cutaneous ,law.invention ,Mice ,Drug Delivery Systems ,Colloid and Surface Chemistry ,Polylactic Acid-Polyglycolic Acid Copolymer ,law ,Animals ,Lactic Acid ,Particle Size ,Physical and Theoretical Chemistry ,Injection pressure ,Syringe ,Transdermal ,Surfaces and Interfaces ,General Medicine ,Injector ,Nanoparticles ,Particle size ,Dispersion (chemistry) ,Polyglycolic Acid ,Body orifice ,Biotechnology ,Biomedical engineering - Abstract
The aim of this study is to investigate the effects of particle size and other injection factors on the skin penetration of nanoparticles delivered with a needle-free injector. Experimental and simulation tests were carried out at various parameters. In addition to testing different sizes of nanoparticles, we also observed the effects of several injection pressures and syringe orifice diameters (SOD) on the dispersion pattern of the nanoparticles after injection. Our results showed that as the nanoparticle size increased from 45 nm to 452 nm, the resulting puncture opening, channel diameter, and depth of the nanoparticle dispersion decreased, but the width of the dispersion increased. Conversely, as the SOD increased, the puncture opening, channel diameter, and depth of the dispersion increased, but width of the dispersion decreased. Increasing the injection pressure also decreased the size, depth, and width of the puncture opening. These results identify how these three parameters affect nanoparticle delivery from a needle-free injector; therefore, our findings will be beneficial for optimization and further study of needle-free injectors as a mechanism for transdermal delivery of nanoparticles.
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- 2014
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80. A study on improving dynamic characteristics of a front lower suspension arm and aerodynamic effects of a hand-made hybrid vehicle
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Guebum Han, Kang-Min Lee, and Seong Keol Kim
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Mechanical Engineering ,Electrical and Electronic Engineering ,Industrial and Manufacturing Engineering - Published
- 2014
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81. A Status Analysis on the Operation of Field Organization in Construction Management Companies
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Kang-Min Lee, Won-Sang Shin, and Chang-Baek Son
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Construction management ,Engineering management ,Knowledge management ,business.industry ,Organizational systems ,Field (Bourdieu) ,business ,Productivity - Published
- 2014
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82. The Effects of Human Resource Management on Organizational Effectiveness
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Kang Min Lee, Min-Soo Kim, Yong-Sun Chang, and Dae Hwan Cho
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Organizational behavior management ,Resource dependence theory ,Process management ,Knowledge management ,business.industry ,Human resource management ,Organizational learning ,Organizational commitment ,business ,Organizational effectiveness ,Organizational behavior and human resources ,Organizational performance - Published
- 2014
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83. Influence of ZrO2 Incorporation into Coating on Electrochemical Response of Low-Carbon Steel Processed By Plasma Electrolytic Oxidation
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Kang Min Lee
- Abstract
The carbon steel is one of the most widely used metals material in engineering with good properties, such as high strength, high toughness, good mechanical properties and low cost. The surface treatment of the steel is essential, however, before use it in industry due to the low corrosion resistivity of steel substrate, which is a problem to use in high humid environment. Meantime it is important to improve the wear resistance and the interfacial adhesion of the coating. Since the thick alumina coating is one of most effective anti-corrosion layer which has high corrosion resistance relatively with the metals, the alumina coating on the steel substrate is good way to improve corrosion resistance. Among the ceramic coating technique for fabrication the alumina layer, such as chemical vapor deposition, magnetron sputter and ionization-assisted beam, plasma electrolytic oxidation (PEO) has been investigation as a new electrochemical surface treatment. PEO process is a unique process that utilized electrochemical reactions to form an oxide layer on a metal surface. The PEO process has been reported to attractive combination of wear resistance and corrosion resistance as well as enhancing thermal property of coating layer. However this advanced coating technique has been performed only if material was valve metals, such as Mg, Al, Ti, Nb and etc. and only a few papers of PEO processed steel have been published. Although several researchers performed PEO process on the steel substrate, the specimen was pretreated by plasma spray, laser re-melting or chemical vapor deposition, therefore it was not convenience to widely use in engineering due to the very high cost and thermal shock to the substrate. The structure and morphology of coating layer formed by PEO process, on the other hand, is influenced on experiment conditions which are composition and concentration of electrolyte, current density and condition of substrate, in particular, composition of electrolyte effect on forming oxide layer. Recently, the incorporation of second oxide nanoparticles into the oxide layer generated by the PEO process in order to improve functionality has received considerable attention. Our previous work has demonstrated that incorporated ZrO2 nanoparticles into oxide layer may enhance the resistance against pitting corrosion. In this study, we conducted PEO process on A36 carbon steel without any pretreatment and successfully formed an incorporated alumina layer with 200-400 nm size of ZrO2 nanoparticles on the carbon steel and prepared comparison specimen which is unincorporated alumina coating with any others during PEO process. The microstructure and phase of coating layers were investigated and corrosion behavior was evaluated by electrochemical impedance spectroscopy.
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- 2019
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84. Severe carbamazepine intoxication unresponsive to albumin-enhanced continuous venovenous hemodiafiltration with low dialysate flow
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Young Kwon Chung, Hoon Suk Park, Mi-Hee Kim, Kyung Y. Chang, Hyung Woo Kim, Tae-Seok Lim, and Kang-Min Lee
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business.industry ,medicine.medical_treatment ,Albumin ,Hematology ,Dialysate flow ,Carbamazepine ,Continuous venovenous hemodiafiltration ,Hemoperfusion ,Extracorporeal ,Nephrology ,Anesthesia ,medicine ,Hemodialysis ,business ,Severe toxicity ,medicine.drug - Abstract
Carbamazepine (CBZ) intoxication can be associated with severe toxicity, including neurological and cardio-respiratory abnormalities. Highly protein-bound, CBZ is not removed efficiently through conventional hemodialysis. Charcoal hemoperfusion is the most effective extracorporeal elimination therapy for CBZ intoxication. Recent reports have indicated that continuous venovenous hemodiafiltration (CVVHDF), albumin-enhanced continuous venovenous hemodialysis, high-flux hemodialysis and plasma exchange can be as effective as charcoal hemoperfusion. In contrast to recent reports, which demonstrated the effectiveness of CVVHDF with high dialysate flow in CBZ intoxication, we observed that serum CBZ level was decreased minimally by albumin-enhanced CVVHDF with low dialysate flow. Therefore, albumin-enhanced CVVHDF with high dialysate flow should be considered in severe CBZ intoxication, if hemoperfusion is unavailable because of the lack of facilities or if it cannot be performed.
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- 2014
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85. Structure and corrosion behavior of oxide layer with Zr compounds on AZ31 Mg alloy processed by two-step plasma electrolytic oxidation
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Kang Min Lee, Bongyoung Yoo, Mohammad Ali Faghihi Sani, Dong Hyuk Shin, and Feryar Einkhah
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Materials science ,Metallurgy ,Alloy ,technology, industry, and agriculture ,Oxide ,Surfaces and Interfaces ,General Chemistry ,Electrolyte ,Plasma electrolytic oxidation ,engineering.material ,Condensed Matter Physics ,Microstructure ,Electrochemistry ,Surfaces, Coatings and Films ,Corrosion ,chemistry.chemical_compound ,Chemical engineering ,chemistry ,Materials Chemistry ,engineering ,Magnesium alloy - Abstract
The formation of the oxide layer with Zr compounds on AZ31 Mg alloy processed by two-step plasma electrolytic oxidation (PEO) has been investigated. After the PEO process first in an alkaline phosphate electrolyte and second in an acid electrolyte containing K2ZrF6, the microstructure, chemical composition, and phase composition of the oxide layers were analyzed via SEM, EDS, and XRD, respectively. The electrochemical reaction and the high temperature caused by the plasma discharges in the electrolyte were the main factors leading to the fabrication of an oxide layer containing Zr compounds on AZ31 Mg alloy. The micro-pores were filled with ZrO2 formed during the PEO process. The results of a potentiodynamic polarization test clearly indicated that the corrosion properties of AZ31 Mg alloy were significantly improved by the two-step PEO process.
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- 2014
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86. Effect of ammonium metavanadate on surface characteristics of oxide layer formed on Mg alloy via plasma electrolytic oxidation
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Young Gun Ko, Dong Hyuk Shin, and Kang Min Lee
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Materials science ,Alloy ,Inorganic chemistry ,Oxide ,Vanadium ,chemistry.chemical_element ,Surfaces and Interfaces ,General Chemistry ,Electrolyte ,engineering.material ,Plasma electrolytic oxidation ,Condensed Matter Physics ,Electrochemistry ,Surfaces, Coatings and Films ,chemistry.chemical_compound ,Ammonium metavanadate ,chemistry ,Coating ,Materials Chemistry ,engineering - Abstract
This study examined the surface characteristics of oxide layers formed on Mg alloy sample by plasma electrolytic oxidation (PEO) coating in phosphate electrolytes with and without ammonium metavanadate (NH 4 VO 3 ). Depending on the addition of NH 4 VO 3 to the electrolyte, the voltage behavior changed significantly with increasing coating time. This was attributed mainly to the different electrochemical reactions, which might cause the formation of V 2 O 3 and V 2 O 5 in the oxide layer. After the PEO coating for 200 s, the size and number of micro pores decreased with the addition of NH 4 VO 3 to the electrolyte. In addition, the surface color of the sample coated in the NH 4 VO 3 -containing electrolyte appeared dark due to the successful incorporation of vanadium oxides. The potentiodynamic polarization test in the 3.5 wt.% NaCl solution showed that the sample PEO-treated in the electrolyte with NH 4 VO 3 had better corrosion-protection properties than that treated without NH 4 VO 3 .
- Published
- 2013
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87. Influence of lactic acid on degradation and biocompatibility of electrospun poly(ε-caprolactone) fibers
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Bo-sang Hwang, Kang-Min Lee, Eun Kyo Kim, Hem Raj Pant, Cheol Sang Kim, Hak Yong Kim, Yu Kyoung Kim, and Chan Hee Park
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Thermogravimetric analysis ,Materials science ,Polymers and Plastics ,Biocompatibility ,Organic Chemistry ,technology, industry, and agriculture ,macromolecular substances ,equipment and supplies ,musculoskeletal system ,Electrospinning ,Lactic acid ,chemistry.chemical_compound ,chemistry ,Chemical engineering ,Nanofiber ,Materials Chemistry ,Fiber ,Composite material ,Fourier transform infrared spectroscopy ,Caprolactone - Abstract
Electrospinning of a poly(e-caprolactone) (PCL)/lactic acid (LA) blend was investigated to fabricate electrospun PCL fibers with improved biodegradability and biocompatibility for biomedical applications. Simple blending of PCL solution with various amounts of LA was used for electrospinning, and the physicochemical properties of the as-fabricated mat were evaluated using various techniques. Scanning electron microscopy showed that fiber diameter decreased with increasing amount of LA. Fourier transform infrared spectroscopy and thermogravimetric analysis also revealed that LA was successfully incorporated in PCL fibers. The presence of LA can accelerate the biodegradation of PCL fibers and enhance the hydrophilicity of a membrane. The adhesion, viability and proliferation properties of osteoblast cells on the PCL/LA composite fibers were analyzed using in vitro cell compatibility tests which showed that LA can increase the cell compatibility of PCL fibers. Additionally, subsequent conversion of LA into calcium lactate by neutralization with calcium base can provide Ca2+ ions on the fiber surface to promote the nucleation of CaPO4 particles. © 2013 Society of Chemical Industry
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- 2013
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88. Synthesis of ZnO-decorated TiO2 nanotubes for dye-sensitized solar cells
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Bongyoung Yoo, Kang Min Lee, Dong Hyuk Shin, and Eung Seok Lee
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Photocurrent ,Materials science ,Anodizing ,Scanning electron microscope ,General Chemical Engineering ,Nanotechnology ,law.invention ,Dielectric spectroscopy ,Dye-sensitized solar cell ,Crystallinity ,Chemical engineering ,law ,Transmission electron microscopy ,Solar cell ,Electrochemistry - Abstract
The effect of ZnO electrodeposition on the photovoltaic efficiency of dye-sensitized solar cells (DSSCs) with anodized TiO 2 nanotubes followed by an annealing process was investigated. ZnO were introduced into anodized TiO 2 nanotubes on Ti foil by electrodeposition in an aqueous electrolyte containing 10 mM Zn(NO 3 ) 2 6H 2 O with different processing time, i.e. 25, 50, 100, and 200 s. The surface morphologies and the crystallinity of the ZnO-decorated TiO 2 nanotubes were inspected via scanning electron microscopy and transmission electron microscopy, respectively. The photovoltaic efficiencies of fabricated DSSCs were characterized by a solar cell measurement system. In addition, we evaluated the kinetics of the photoelectrochemical phenomena in DSSCs via electrochemical impedance spectroscopy with a focus on exploring the electron lifetime and internal resistance of the cells in a quantitative manner based on an equivalent circuit model. It was found that the photovoltaic efficiency of DSSCs with ZnO-decorated TiO 2 nanotubes for 50 s was improved by more than 60%, compared to DSSCs with as-prepared TiO 2 nanotubes. This improvement is ascribed to increased dye loading and photocurrent density.
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- 2013
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89. MAEPER: Matching Access and Error Patterns With Error-Free Resource for Low Vcc L1 Cache
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Sungjoo Yoo, Jung Ho Ahn, Sunggu Lee, Younggeun Choi, and Kang-min Lee
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Instruction prefetch ,CPU cache ,Computer science ,Cache coloring ,Pipeline burst cache ,Cache pollution ,Cache-oblivious algorithm ,Non-uniform memory access ,Cache invalidation ,Write-once ,Victim cache ,Electrical and Electronic Engineering ,Cache algorithms ,Hardware_MEMORYSTRUCTURES ,business.industry ,MESI protocol ,Locality ,Cache-only memory architecture ,Smart Cache ,Hardware and Architecture ,Bus sniffing ,Page cache ,Cache ,business ,Least frequently used ,Software ,Computer hardware ,Computer network - Abstract
Large SRAMs are the practical bottleneck to achieve a low supply voltage, because they suffer from process variation-induced bit errors at a low supply voltage. In this paper, we present an error-resilient cache architecture that resolves the drawback of previous approaches, i.e., the performance degradation at a low supply voltage which is caused by cache misses in accesses to faulty resources. We utilize cache access locality and error-free resources in a cost-effective manner. First, we classify cache lines into fully and partially accessed groups and apply appropriate methods to each group. For the partially accessed group, we propose a method of matching memory access behavior and error locations with intra-cache line word-level remapping. In order to reduce the area overhead used to store the cache access information history, we present an access pattern-learning line-fill buffer (LFB). For the fully accessed group, we propose the utilization of error-free assist functions in the cache, i.e., a LFB and victim cache with no process variation-induced error at the target minimum supply voltage. We also present an error-aware prefetch method that allows us to utilize the error-free victim cache to achieve a further reduction in cache misses due to faulty resources. Experimental results show that the proposed method gives an average 32.6% reduction in cycles per instruction at an error rate of 0.2% with a small area overhead of 8.2%.
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- 2013
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90. Effect of icosahedral phase on growth behavior of thin oxide film on MgZn12Y1.7 alloy via micro arc oxidation
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Kang Min Lee, Young Gun Ko, and Dong Hyuk Shin
- Subjects
Materials science ,Icosahedral symmetry ,Alloy ,Metals and Alloys ,Surfaces and Interfaces ,engineering.material ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,Crystallography ,Coating ,Chemical engineering ,Electrical resistivity and conductivity ,Phase (matter) ,X-ray crystallography ,Materials Chemistry ,engineering ,Thin film ,Current density - Abstract
The effect of the icosahedral phase on the growth behavior of the thin oxide film coated on MgZn 12 Y 1.7 alloy sample by micro arc oxidation (MAO) was studied. During MAO coating in a phosphate electrolyte with a current density of 25 mA/cm 2 , the responding voltage of the present sample gradually increased as the coating time increased up to 80 s. The surface structure observations indicated that the thin oxide film was prone to be formed more easily on the top of the icosahedral phase than on that of the α-Mg phase matrix in the MgZn 12 Y 1.7 alloy sample. This implies that the growth rates of the thin oxide films were different and were also enhanced on the icosahedral phase, which could be explained by the low electrical conductivity of the icosahedral phase itself leading to appreciable micro arcs during MAO coating.
- Published
- 2013
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91. Methyl Red Decolorization Efficiency of a Korea Strain of
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Beom-Su, Kim, Mohamed, Blaghen, and Kang-Min, Lee
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Aspergillus ,Bioreactors ,Glucose ,Glucuronic Acid ,Alginates ,Polymers ,Hexuronic Acids ,Temperature ,Cells, Immobilized ,Hydrogen-Ion Concentration ,Azo Compounds ,Water Pollutants, Chemical - Abstract
Intensive research studies have revealed that fungal decolorization of dye wastewater is a promising replacement for the current process of dye wastewater decolorization. The authors isolated an Aspergillus sp. from the effluent of a textile industry area in Korea and assessed the effects of a variety of operational parameters on the decolorization of methyl red (MR) by this strain of Aspergillus sp. This Aspergillus sp. was then immobilized by entrapment in several polymeric matrices and the effects of operational conditions on MR decolorization were investigated again. The optimal decolorization activity of this Aspergillus sp. was observed in 1% glucose at a temperature of 37 °C and pH of 6.0. Furthermore, stable decolorization efficiency was observed when fungal biomass was immobilized into alginate gel during repeated batch experiment. These results suggest that the Aspergillus sp. isolated in Korea could be used to treat industrial wastewaters containing MR dye.
- Published
- 2017
92. Corni Fructus Containing Formulation Attenuates Weight Gain in Mice with Diet-Induced Obesity and Regulates Adipogenesis through AMPK
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Su Jin Kim, Hara Lim, Hong-Kun Rim, Seong-Gyu Ko, Mi-Young Jeong, Seung-Heon Hong, Jae-Young Um, Sunghoon Kim, Kang-Min Lee, Kyung-Tae Lee, Byung-Cheol Lee, Hyejung Lee, Hyeung-Jin Jang, Jinbong Park, Yong-Deok Jeon, and Hye-Lin Kim
- Subjects
medicine.medical_specialty ,Article Subject ,medicine.diagnostic_test ,business.industry ,AMPK ,lcsh:Other systems of medicine ,lcsh:RZ201-999 ,chemistry.chemical_compound ,Endocrinology ,Complementary and alternative medicine ,chemistry ,Downregulation and upregulation ,Western blot ,Adipogenesis ,Adipocyte ,Internal medicine ,medicine ,Oil Red O ,Receptor ,Protein kinase A ,business ,Research Article - Abstract
Obesity is a metabolic disorder characterized by chronic inflammation and dyslipidemia and is a strong predictor for the development of hypertension, diabetes mellitus, and cardiovascular disease. This study examined the antiobesity effect of an ethanol extract of Corni Fructus containing formulation (CDAP), which is a combination of four natural components: Corni Fructus, Dioscoreae Rhizoma, Aurantii Fructus Immaturus, and Platycodonis Radix. The cellular lipid content in 3T3-L1 adipocytes was assessed by Oil Red O staining. Expressions of peroxisome proliferator-activated receptor-γ(PPAR-γ), CCAAT/enhancer-binding protein-α(C/EBP-α), and lipin-1 were determined by real-time RT-PCR. Western blot was used to determine the protein levels of PPAR-γ, C/EBP-α, and AMP-activated protein kinase-α(AMPK-α). The CDAP extract suppressed the differentiation of 3T3-L1 adipocytes by downregulating cellular induction of PPAR-γ, C/EBP-α, and lipin-1. The CDAP extract also significantly upregulated phosphorylation of AMPK-α. Anin vivostudy showed that CDAP induced weight loss in mice with high-fat-diet-induced obesity. These results indicate that CDAP has a potent anti-obesity effect due to the inhibition of adipocyte differentiation and adipogenesis.
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- 2013
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93. SH003 induces apoptosis of DU145 prostate cancer cells by inhibiting ERK-involved pathway
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Youn Kyung Choi, Seong-Gyu Ko, Yu-Jeong Choi, Sung-Gook Cho, Kang Min Lee, and Soo-Yeon Kang
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0301 basic medicine ,MAPK/ERK pathway ,Male ,Programmed cell death ,MAP Kinase Signaling System ,Apoptosis ,Trichosanthes ,Pharmacology ,urologic and male genital diseases ,SH003 ,Herbal medicine ,ERK pathway ,DU145 human prostatecancer cells ,Anticancer effect ,03 medical and health sciences ,Prostate cancer ,0302 clinical medicine ,DU145 ,Annexin ,Cell Line, Tumor ,LNCaP ,Medicine ,Humans ,Viability assay ,Angelica ,business.industry ,Plant Extracts ,Prostatic Neoplasms ,General Medicine ,Astragalus Plant ,medicine.disease ,030104 developmental biology ,Complementary and alternative medicine ,030220 oncology & carcinogenesis ,Cancer research ,DU145 human prostate cancer cells ,Drug Screening Assays, Antitumor ,business ,Research Article - Abstract
Background Herbal medicines have been used in cancer treatment, with many exhibiting favorable side effect and toxicity profiles compared with conventional chemotherapeutic agents. SH003 is a novel extract from Astragalus membranaceus, Angelica gigas, and Trichosanthes Kirilowii Maximowicz combined at a 1:1:1 ratio that impairs the growth of breast cancer cells. This study investigates anti-cancer effects of SH003 in prostate cancer cells. Methods SH003 extract in 30% ethanol was used to treat the prostate cancer cell lines DU145, LNCaP, and PC-3. Cell viability was determined by MTT and BrdU incorporation assays. Next, apoptotic cell death was determined by Annexin V and 7-AAD double staining methods. Western blotting was conducted to measure protein expression levels of components of cell death and signaling pathways. Intracellular reactive oxygen species (ROS) levels were measured using H2DCF-DA. Plasmid-mediated ERK2 overexpression in DU145 cells was used to examine the effect of rescuing ERK2 function. Results were analyzed using the Student’s t-test and P-values
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- 2016
94. Purification and characterization of a melanin biodegradation enzyme from Geotrichum sp
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Hong‐Sig Hong, Mohamed Blaghen, Kang-Min Lee, and Beom-Su Kim
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0106 biological sciences ,0301 basic medicine ,Aging ,Pharmaceutical Science ,Geotrichum ,Dermatology ,01 natural sciences ,Melanin ,03 medical and health sciences ,Colloid and Surface Chemistry ,010608 biotechnology ,Drug Discovery ,Humans ,chemistry.chemical_classification ,Laccase ,Melanins ,integumentary system ,biology ,Chemistry ,Lignin peroxidase ,Biodegradation ,biology.organism_classification ,Chromatography, Ion Exchange ,Enzyme assay ,030104 developmental biology ,Enzyme ,Biochemistry ,Peroxidases ,Chemistry (miscellaneous) ,biology.protein ,Electrophoresis, Polyacrylamide Gel ,Peroxidase - Abstract
Objective Melanin is a black or brown phenolic polymer present mainly in skin and hair. Although melanin can be degraded by some microbial species, the melanin degradation capacity of Geotrichum sp. is unknown. The aim of this study was to characterize a melanin biodegradation enzyme from Geotrichum sp. Methods In this study, we assessed the melanin degradation activity of Geotrichum sp. in comparison with the major melanin-degrading enzymes, manganese-dependent peroxidase (MnP), manganese-independent peroxidase, lignin peroxidase and laccase. Furthermore, the effect of several carbohydrates on melanin degradation by Geotrichum sp. was determined. The MnP enzyme was purified using ammonium sulphate precipitation and Sephadex G-200 column chromatography, and then the conditions for optimal enzymatic activity were determined by adjusting the pH, temperature and Tween-80 concentration. Results Compared with extracellular ligninolytic enzymes of Geotrichum sp., MnP had the highest ligninolytic enzyme activity; and the highest enzymatic activity was observed in the presence of glucose. The final purified MnP enzyme exhibited 6 U mL−1 activity and had a molecular weight of 54.2 kDa. The enzymatic activity was highest at pH 4.5 and 25–35°C in the absence of Tween-80. Conclusion These results indicate the potential of MnP purified from Geotrichum sp. as a skin-lightening agent in the cosmetic industry.
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- 2016
95. Angelica acutiloba Kitagawa Extract Attenuates DSS-Induced Murine Colitis
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Seong-Gyu Ko, Kang Min Lee, and Jong-Chan Jang
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0301 basic medicine ,Diarrhea ,Male ,Angelica acutiloba ,Article Subject ,Immunology ,Interleukin-1beta ,Pharmacology ,Immunoglobulin E ,03 medical and health sciences ,Interferon-gamma ,Mice ,0302 clinical medicine ,Oral administration ,Weight Loss ,lcsh:Pathology ,medicine ,Matrix Metalloproteinase 14 ,Animals ,Colitis ,Chromatography, High Pressure Liquid ,Angelica ,biology ,business.industry ,Interleukin-6 ,Plant Extracts ,Tumor Necrosis Factor-alpha ,Dextran Sulfate ,Cell Biology ,medicine.disease ,biology.organism_classification ,Ulcerative colitis ,Interleukin-12 ,Anorexia ,Interleukin-10 ,Interleukin 10 ,030104 developmental biology ,Matrix Metalloproteinase 9 ,biology.protein ,030211 gastroenterology & hepatology ,Tumor necrosis factor alpha ,medicine.symptom ,business ,lcsh:RB1-214 ,Research Article - Abstract
We examined the protective effects ofAngelica acutilobaKitagawa (AAK) extract on a murine model of acute experimental colitis. Colitis was induced by 4% dextran sulfate sodium (DSS) in the drinking water of male C57BL/6 mice, for 7 consecutive days. Oral administration of AAK extract (500 mg/kg/day) significantly alleviated DSS-induced symptoms such as anorexia, weight loss, events of diarrhea or bloody stools, and colon shortening. Histological damage was also ameliorated, as evidenced by the architectural preservation and suppression of inflammatory cell infiltration in colonic samples. Treatment improved the colonic mRNA expression of different inflammatory markers: cytokines, inducible enzymes, matrix metalloproteinases, and tight junction-related proteins. In the isolated serum, IgE levels were downregulated. Collectively, these findings indicate the therapeutic potentials of AAK as an effective complementary or alternative modality for the treatment of ulcerative colitis.
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- 2016
96. Study of a liquid crystal structure with improved electro-optical characteristics
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Ji-Hun Lim, Byeong-Yun Oh, Byoung-Yong Kim, Young-Hwan Kim, Kang-Min Lee, Jeoung-Min Han, Sang-Keuk Lee, and Dae-Shik Seo
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Electrooptics -- Analysis ,Liquid crystals -- Electric properties ,Liquid crystals -- Optical properties ,X-ray spectroscopy -- Usage ,Physics - Abstract
The resulting electro-optical (EO) characteristics of various pretilt angles are measured and compared to the EO characteristics of a conventional in-plane switching (IPS)-liquid crystal display (LCD). The vertically aligned twisted nematic IPS (VPS)-LCDs have overcome many viewing angle and transmittance curve problems, whereas multidomain vertical alignment LCDs and IPS-LCDs have resolved only one problem.
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- 2009
97. Effect of ion beam irradiation and rubbing on the directional behavior and alignment mechanism of liquid crystals on polyimide surfaces
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Kang-Min Lee, Byeong-Yun Oh, Young-Hwan Kim, and Dae-Shik Seo
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Electrostatic interactions -- Analysis ,Ion bombardment -- Usage ,Liquid crystals -- Structure ,Liquid crystals -- Electric properties ,Spectrum analysis -- Usage ,Physics - Abstract
The effects of ion beam (IB) irradiation and rubbing on the directional behavior and alignment mechanism of liquid crystals (LCs) on polyimide (PI) surfaces are examined. The studies have shown that the LC direction has depended strongly on the C-O bonds created from C[double bond]O bonds on the PI surface broken by IB irradiation and x-ray photoelectron spectroscopy is used for studying the chemical bonding state of the PI surface.
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- 2009
98. Evaluation of plasma temperature during plasma oxidation processing of AZ91 Mg alloy through analysis of the melting behavior of incorporated particles
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Kang Min Lee, Byung Uk Lee, Bongyoung Yoo, Dong Hyuk Shin, Sang Il Yoon, and Eung Seok Lee
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Range (particle radiation) ,Materials science ,Magnesium ,General Chemical Engineering ,Alloy ,Metallurgy ,Oxide ,chemistry.chemical_element ,Plasma ,engineering.material ,Plasma electrolytic oxidation ,chemistry.chemical_compound ,chemistry ,Chemical engineering ,Phase (matter) ,Electrochemistry ,engineering ,Ternary operation - Abstract
Plasma electrolytic oxidation (PEO) process was used to incorporate TiO2 and ZrO2 particles into a magnesium oxide layer. Whereas incorporated ZrO2 particles were clearly observed in the PEO-treated oxide layer, TiO2 particles were scarce in the oxide layer because the temperature of the plasma was between the melting temperature of the TiO2 particles and that of the ZrO2 particles. XRD patterns, TEM images, and SAED patterns also provided strong evidence that the TiO2 particles were melted or transformed, which generated a new ternary oxide phase, MgxTiyO. Because cubic ZrO2 was not observed and could possibly exist at a temperature greater than 2643 K, which was the temperature for the phase transformation to the cubic structure, the temperature of the oxide melted by plasma was estimated to be in the range of 2116–2643 K.
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- 2012
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99. Surface reformation and electro-optical characteristics of liquid crystal alignment layers using ion beam irradiation
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Byeong-Yun Oh, Kang-Min Lee, Byoung-Yong Kim, Young-Hwan Kim, Jin-Woo Han, Jeong-Min Han, Sang-Keuk Lee, and Dae-Shik Seo
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Argon -- Electric properties ,Ion bombardment -- Usage ,Liquid crystals -- Structure ,Liquid crystals -- Electric properties ,Liquid crystals -- Optical properties ,Physics - Abstract
The surface modification characteristics of liquid crystal (LC) alignment layers irradiated with various argon (Ar) ion beam (IB) energies are examined as a substituted for rubbing technology. The chemical structure analysis has showed that the alignment ability of LCs is because of the preferential reorientation of the carbon network due to the breaking of C[double bond]O double bonds in the imide ring parallel to the incident IB direction.
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- 2008
100. Incorporation of carbon nanotubes into micro-coatings film formed on aluminum alloy via plasma electrolytic oxidation
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Young Gun Ko, Dong Hyuk Shin, and Kang Min Lee
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Materials science ,Mechanical Engineering ,Alloy ,Metallurgy ,chemistry.chemical_element ,Carbon nanotube ,engineering.material ,Plasma electrolytic oxidation ,Condensed Matter Physics ,Microstructure ,law.invention ,chemistry ,Chemical engineering ,Coating ,Mechanics of Materials ,Aluminium ,law ,engineering ,General Materials Science ,Magnesium alloy ,Current density - Abstract
The influence of the incorporation of carbon nanotubes (CNTs) on the coating structure of aluminum alloy processed by plasma electrolytic oxidation (PEO) has been studied as a function of the current density. A series of PEO coatings was applied in a silicate-electrolyte containing CNTs at three current densities, such as 50, 100, and 150 mA/cm 2 . As the current density increased, the responding voltage also increased due to a gradual increment in the amount of CNTs incorporated uniformly into the coating film. In addition, a number of CNTs were observed mainly near micro-pores formed in the coating film by plasma explosive arcs, resulting in a fairly uniform coating structure with a low density of micro-pores. This phenomenon was discussed based on the electrophoretic activity of CNTs.
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- 2011
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