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210 results on '"Lee, Ye-Eun"'

25. Aerial Imaging-Based Fuel Information Acquisition for Wildfire Research in Northeastern South Korea.

Author

Kwon, Kyeongnam, Kwon, Chun Geun, Lee, Ye-eun, Kim, Sung Yong, and Im, Seong-kyun

Subjects
OPTICAL radar, LIDAR, WILDFIRE prevention, AERIAL photographs, QUANTILE regression, FIELD research
Abstract

Tree detection and fuel amount and distribution estimation are crucial for the investigation and risk assessment of wildfires. The demand for risk assessment is increasing due to the escalating severity of wildfires. A quick and cost-effective method is required to mitigate foreseeable disasters. In this study, a method for tree detection and fuel amount and distribution prediction using aerial images was proposed for a low-cost and efficient acquisition of fuel information. Three-dimensional (3D) fuel information (height) from light detection and ranging (LiDAR) was matched to two-dimensional (2D) fuel information (crown width) from aerial photographs to establish a statistical prediction model in northeastern South Korea. Quantile regression for 0.05, 0.5, and 0.95 quantiles was performed. Subsequently, an allometric tree model was used to predict the diameter at the breast height. The performance of the prediction model was validated using physically measured data by laser distance meter triangulation and direct measurement from a field survey. The predicted quantile, 0.5, was adequately matched to the measured quantile, 0.5, and most of the measured values lied within the predicted quantiles, 0.05 and 0.95. Therefore, in the developed prediction model, only 2D images were required to predict a few of the 3D fuel details. The proposed method can significantly reduce the cost and duration of data acquisition for the investigation and risk assessment of wildfires. [ABSTRACT FROM AUTHOR]

Published
2023
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31. Triterpenoids from the leaves of Osmanthus fragrans var. aurantiacus with their anti-melanogenesis and anti-tyrosinase activities

Author

Le, Duc Dat, Lee, Ye Eun, and Lee, Mina

Subjects
Organic Chemistry, Plant Science, Biochemistry, Analytical Chemistry
Abstract

Excessive production of melanin causes various dermatological disorders including hyperpigmentation. To search for anti-melanogenesis candidates from natural products, we discovered that leaves of Osmanthus fragrans var. aurantiacus (OFA) suppressed melanin production. The extract of OFA leaves and its fractions were subjected to bioactivity-guided separation by targeting active constituents and a total of four triterpenoids were obtained: 3α,24-dihydroxyurs-12-en-28 oic acid (1), pomolic acid (2), maslinic acid (3), and corosolic acid (4). Compounds 1 and 2 were isolated from this plant for the first time. All compounds were evaluated for their inhibitory activities against melanin production and tyrosinase activity. Active compounds were further investigated to understand their mechanisms of action. Results revealed that they significantly down-regulated TYRP-1 and TYRP-2 expression levels. Our results clarified the whitening property of this plant and provided evidence that active constituents of this plant possessed anti-melanogenesis effect and anti-tyrosinase activity for the first time.

Published
2022

39. Proposal of facial pigmentary unit and facial hyperpigmentation type for Fitzpatrick skin types II‐IV.

Author

Oh, Seung‐Min, Lee, Ye Eun, Ko, Min Ji, Baek, Ji Hwoon, and Shin, Min Kyung

Subjects
*HYPERPIGMENTATION, *MELANINS, *VOLUNTEERS, *PIGMENTS, *NECK
Abstract

Background: Studies on facial hyperpigmentation across different facial units are limiting. We aimed to analyze melanin pigmentation images to observe facial pigmentary demarcation lines (FPDLs) and suggest facial hyperpigmentation types for normal individuals. Materials and methods: 3D facial melanin pigmentation images of 173 volunteers were obtained and analyzed for the presence of FPDLs. Pigmentation severity was assessed for each of the thirteen facial pigment units. The images were then grouped according to a pattern of hyperpigmentation to suggest three facial hyperpigmentation types—dark spot, photoaging and post‐inflammatory hyperpigmentation. Results: Four groups of FPDLs including a novel group I were observed. Nasal, frontal, auricular were the darkest pigmented facial pigment unit, and the anterior neck was the least pigmented. The dark spot type was the most common facial hyperpigmentation type. The photoaging type and the PIH type showed age‐dependent distribution, as the photoaging type was more common among the subjects over 40s, and the PIH type was more common in younger subjects. Conclusion: Facial hyperpigmentation among healthy individuals with Fitzpatrick skin types II‐IV is often accompanied by FPDLs and categorized into three types. Each type is modeled after the pattern of pigmentation associated with certain dermatological disorders. The practical implications of facial hyperpigmentation types can be resourceful in various fields including prevention and treatment of pigmentary disorders. [ABSTRACT FROM AUTHOR]

Published
2023
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