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조현이,정종철,김호성,최재욱,성대경,서지훈,김성범,이계혁 大韓顎顔面成形再建外科學會 2000 Maxillofacial Plastic Reconstructive Surgery Vol.22 No.1
Osteosarcoma is a primary malignant tumor arising most often in the long bone, but rare in jaw bone. Especially osteogenic sarcoma of the mandible is a rare tumor, comprising less than 0.5% of all head and neck tumors. Osteosarcoma occurs cheifly in young persons, and presenting very survival rates. Histopathologically this tumor can be classified three types, osteoblastic, fibroblastic, chondroblastic and classified from low grade to high grade by anaplasia or mitosis of the tumor cells. Sometimes, the exact diagnosis of osteosarcoma is difficult especially in low grade osteosarcoma, even if clinical or radiographical findings suggest to osteosarcoma. So suspcious to malignant bone tumor in clinical or radiological findings, biopsy should be taked from deep portion and multiple area, and sharing the patient history and radiographs with pathologist will assist in the development of the diagnosis. We report a case of low grade osteosarcoma on the mandible initially difficulty in accurate diagnosis. The patient visited our hospital for routine dental treatment but radiographic findings displayed ill-defined radiolucency with osteoid formation on the mandible. Final diagnosis was difficulty in initial biopsy but subsequent biopsy taked from deep portion presented infiltrative growth and mitosis of the tumor cell in some area with small osteoid bone formation, so we could reach final diagnosis as low grade sarcoma. We treated this patient with bloc resection of the mandible and immediate reconstruction with iliac corticocancellous block.
A study on freeboard assessment of agricultural reservoirs considering climate change
Choi, Ji-Hyeok,Moon, Young-Il 한국수자원학회 2018 한국수자원학회논문집 Vol.51 No.4
국내 농업용 저수지 댐 시설물은 노후화 및 기후변화로 인한 여름철 강우량 증가로 인해 수자원관리에 대한 어려움뿐만 아니라 댐 월류에 따른 피해위험이 높을 것으로 전망된다. 따라서 본 연구에서는 기후변화를 고려한 농업용 저수지 수문학적 안전성을 평가하기 위해 농업용 저수지 1종 댐시설물을 대상유역으로 선정하였으며, 유역별 확률강우량, 기존에 제시된 Present PMP, 기상청 기후변화시나리오에 따른 Future PMP를 산정하였다. 또한, 기후변화에 따라 증가하는 강우량을 정량적으로 분석하고, 홍수량산정 및 저수지홍수추적을 실시하여 강우시나리오에 따른 농업용 저수지의 여유고를 분석하였다. 기후변화를 고려한 Future PMP를 이용하여 농업용 저수지 댐 시설물의 수문학적 안전성을 평가한 결과, 고삼, 금광, 미호, 청천저수지는 설계홍수위 이상의 최고수위가 발생함에 따라 월류위험에 취약할 것으로 분석되었다. Domestic agricultural reservoir dam facilities are difficult to manage water resources because of the in summer rainfall increase due to aging and climate change, it is expected that the dam risk will be large due to the overflow. In this study, author selected study basin in order to evaluate hydrological safety of agricultural reservoir dam facilities. And calculated the probable rainfall, Present PMP, Future PMP considering climate change. Also, author carried quantitative analysis out for increasing rainfall due to climate change, analyze freeboard assessment of agricultural reservoir by calculate flood discharge, reservoir flood routing according to rainfall scenarios. As a result of evaluate hydrological safety of agricultural reservoir dam facilities using Future PMP considering climate change, Gosam, Kumkwang, Miho, Cheongcheon reservoir had the Highest Water Level over the design flood level, it is analyzed that it would be vulnerable to overflow risk.
Epiglottic Cyst Treated with Electrocautery: A Case Report
Ji Hyeok Choi,Sang Joon Lee,Phil-Sang Chung,Seung Hoon Woo 대한의학레이저학회 2022 MEDICAL LASERS Vol.11 No.1
Epiglottic cysts which usually occur on the lingual side of the epiglottis, are often benign lesions. This is a case report of a 40-year-old woman who visited our hospital and was found to have an epiglottic cyst during a gastroscopy procedure. We removed the epiglottic cyst via laryngo-microsurgery using electrocautery. After the surgery, the shape and function of the epiglottis were completely preserved, and complications such as aspiration symptoms did not occur. Therefore, it is believed that the procedure could be established as an alternative or complementary surgical method for the removal of epiglottic cysts.
Ji Hyeok Choi,Ji Eun Choi,So-Young Chang,이민영,Jae Yun Jung 대한의학레이저학회 2022 MEDICAL LASERS Vol.11 No.4
Background and Objectives: This research was designed to establish an animal model of cochlear ischemia using non-invasive photochemical reaction.Materials and Methods: Rose bengal (RB) was administered to male Sprague-Dawley rats at 6 weeks of age through an intraperitoneal (IP) or intravenous (IV) injection. At five minutes after the RB injection, a 532 nm diode laser was used to irradiate the rats for 5, 10, and 15 minutes using a transcanal approach. The results of the auditory brainstem response at one, three, and seven days after the procedure were compared. On the 10th day, the cochleae were obtained to prepare tissue sections for pathohistological examination.Results: For all the nine rats in the RB IP-injection group, hearing loss was not observed in any of the nine different conditions. For rats in the RB IV-injected group, hearing loss was not observed when 532 nm light was used for irradiation at 150 mW or 175 mW for 5 or 10 minutes. However, for rats irradiated for 15 minutes, hearing loss of more than 70 dB was observed at all frequencies one day later. Hearing loss of more than 50 dB persisted until 10 days later. Further pathohistological examinations of these rats revealed the destruction of the normal structure of the organ of Corti and stria vascularis.Conclusion: The results of the present study demonstrate that the IV injection of RB with transcanal green light irradiation can induce cochlear ischemia in rats. This method could be useful for developing a model of cochlear ischemia.
Dam Rehabilitation Assessment Using the Delphi-AHP Method for Adapting to Climate Change
Choi, Ji-Hyeok,Yoon, Tae-Hyung,Kim, Jong-Suk,Moon, Young-Il American Society of Civil Engineers 2018 Journal of water resources planning and management Vol.144 No.2
<P>Extreme climate events are expected to become more severe or frequent under climate change projections, and these future changes continue to be an urgent concern for the aging water infrastructure in East Asia and Pacific countries. In this study, the authors suggest an approach to dam rehabilitation assessment to prepare for the complex dam safety and environmental issues caused by climate change and aging dam facilities in South Korea. The authors review the validity of each evaluation component and the appropriateness of all criteria through research into both domestic and foreign cases, literature review, and consultation with dam rehabilitation assessment experts. In addition, the authors propose quantitative evaluation indices and a comprehensive importance evaluation of dam rehabilitation using a survey-based Delphi-analytic hierarchy process (AHP) method, in accordance with the professional experience of panel participants. (c) 2017 American Society of Civil Engineers.</P>
Choi, Ji Na,Choi, Yun-Hyeok,Lee, Jeong-Min,Noh, Ill Chan,Park, Jae Won,Choi, Wahn Soo,Choi, Jung Ho Taylor Francis Health Sciences 2012 NATURAL PRODUCT RESEARCH Vol.26 No.24
<P>Trachelospermum jasminoides (Apocynaceae) has pharmacological effects that include anti-inflammatory, anti-bacterial and anti-viral activities, which have been observed from various studies. Of these pharmacological effects, the anti-inflammatory capacity of compounds from T. jasminoides is not yet known exactly. In this study, we investigated the compound that can be used for the suppression of lipopolysacchaide (LPS) stimulated inflammatory responses in macrophages among the five isolated compounds. β-sitosterol-β-D-glucoside (1) was found to reduce nitric oxide (NO) production from LPS-induced RAW 264.7 cells the most. In addition, compound 1 strongly inhibited the interleukin 6 (IL-6) activities of stimulated macrophages. Treatment of RAW 264.7 cells with compound 1 reduced secretion of inflammatory elements including tumour necrosis factor - alpha (TNF-α) and interleukin 1 beta (IL-1β). Thus, compound 1 may be a useful candidate for the development of new drugs to treat endotoxemia and inflammation accompanied by the overproduction of NO.</P>
Interregional synaptic maps among engram cells underlie memory formation
Choi, Jun-Hyeok,Sim, Su-Eon,Kim, Ji-il,Choi, Dong Il,Oh, Jihae,Ye, Sanghyun,Lee, Jaehyun,Kim, TaeHyun,Ko, Hyoung-Gon,Lim, Chae-Seok,Kaang, Bong-Kiun American Association for the Advancement of Scienc 2018 Science Vol.360 No.6387
<P>Memory resides in engram cells distributed across the brain. However, the site-specific substrate within these engram cells remains theoretical, even though it is generally accepted that synaptic plasticity encodes memories. We developed the dual-eGRASP (green fluorescent protein reconstitution across synaptic partners) technique to examine synapses between engram cells to identify the specific neuronal site for memory storage. We found an increased number and size of spines on CA1 engram cells receiving input from CA3 engram cells. In contextual fear conditioning, this enhanced connectivity between engram cells encoded memory strength. CA3 engram to CA1 engram projections strongly occluded long-term potentiation. These results indicate that enhanced structural and functional connectivity between engram cells across two directly connected brain regions forms the synaptic correlate for memory formation.</P>
Seasonal distribution of airborne pollen in Ulsan, Korea in 2009-2010
Choi, Seung-Hyeok,Jung, In-Yong,Kim, Dong-Yeop,Kim, Yang-Ho,Lee, Ji-Ho,Oh, In-Bo,Choi, Kee-Ryong The Ecological Society of Korea 2011 Journal of Ecology and Environment Vol.34 No.4
To determine the peak dispersal times of allergenic pollen grains in Ulsan, Korea, we performed continuous airborne pollen counts at three stations (Sts. A, B, and C) in Ulsan from August 2009 to November 2010. Pollen grains were sampled using a Durham sampler. Two peak pollen dispersal seasons were observed per year. The peak seasons generally coincided with the flowering period of anemophilous trees: Taxodiaceae (February), Alnus (March), Cupressaceae (April), Quercus, and Pinus (May), and with the flowering phase of herbs from August to November, e.g., Humulus, Artemisia, Gramineae, and Ambrosia from August through September. The highest concentration of airborne pollen was from Pinus (68%), followed by Quercus (15%), Alnus (6%), and Humulus (2%); whereas very low pollen concentrations were from Taxodiaceae, Cupressaceae, Artemisia, Gramineae, and Ambrosia (${\leq}$ 1% of the annual total airborne pollen concentration). Our findings indicate that Alnus and Humulus pollen are major allergens whereas those of Pinus and Quercus are minor allergens. The concentration of Alnus pollen grains at St. C was over five times that at Sts. A and B. This finding implies that individuals living at or near St. C are exposed to high concentrations of Alnus pollen before and after March, which is the flowering period of the alder tree. From August to September, individuals living at or near St. B are exposed to high concentrations of Humulus pollen. Our study suggests that Alnus pollen may be the major aeroallergen causing pollinosis in the spring at St. C and Humulus pollen may be the major aeroallergen in autumn at St. B.