• 한국안전학회지
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• 제33권3호
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• pp.58-64
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• 2018

Recently, a lot of accident report documents have accumulated in almost all of industries, including critical information of accidents. Accordingly, text data contained in accident report documents are considered useful information for understanding accident processes. However, there has been a lack of systematic approaches to analyzing accident report documents. In this respect, this paper aims at proposing text analytics approach to extracting critical information on accident processes. To be specific, major causes of the accident occurrence are classified based on text information contained in accident report documents by using both textmining and latent Dirichlet allocation (LDA) algorithms. The textmining algorithm is used to structure the document-term matrix and the LDA algorithm is applied to extract latent topics included in a lot of accident report documents. We extract ten topics of accidents as accident types and related keywords of accidents with respect to each accident type. The cause-and-effect diagram is then depicted as a tool for navigating processes of the accident occurrence by structuring causes extracted from LDA. Further, the trends of accidents are identified to explore patterns of accident occurrence in each of types. Three patterns of increasing to decreasing, decreasing to increasing, or only increasing are presented in the case of a chemical plant. The proposed approach helps safety managers systematically supervise the causes and processes of accidents through analysis of text information contained in accident report documents.

• Journal of Applied Biological Chemistry
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• 제61권4호
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• pp.417-421
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• 2018

자외선은 가시 광선보다 파장이 짧은 전자기파이며, 오존층을 통과하는 자외선이 피부 노화의 주요 원인이다. 피부 조직을 자외선에 만성적으로 노출 시키면 인간 각질 형성 세포에서 Mitogen-activated Protein Kinases (MAPKs) 신호 전달 경로가 활성화되어 매트릭스 metalloproteinases (MMPs) 생성이 증가한다. 본 연구에서는 제주도의 초본 추출물을 대상으로 자외선 자극을 통해 인간 각질 형성 세포(HaCaTs)의 항 노화 효과에 대해 조사 하였다. 우리는 자외선 유도 된 각질 형성 세포에서 MMP-1 유전자와 단백질 발현 수준을 측정 하였으며 그 결과, Thymus quinquecostatus 추출물(TQE)은 자외선 조사된 HaCaT 세포에서 의해 농도 의존적으로 MMP-1의 발현을 유의하게 감소시키는 것으로 확인되었다. 또한, TQE는 MAPK 신호 전달요소 인 ERK1/2, JNK1/2 및 p38 단백질의 자외선 유도에 따른 인산화를 유의 적으로 감소시켰다. 이러한 결과는 MAPKs 경로가 인간 각질 세포에서 UV 유도 MMP-1 생산에 대한 TQE의 억제 효과에 기여할 수 있음을 시사한다. 우리의 결과는 아마도 인간 각질형성 세포에서 TQE가 자외선 유도된 MMP-1 생산을 억제하는 피부 노화 소재로 활용될 수 있음을 시사한다.

• 대한통합의학회지
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• 제12권1호
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• pp.63-71
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• 2024

Purpose : Skin is the primary barrier to protect the body from various exogenous factors. Among them, UVB exposure can cause the induction of not only excessive inflammatory responses but also the degradation of extracellular matrix (ECM), including collagen and elastin. This study tried to investigate the ameliorative effect of Persicaria perfoliata ethanol extract (PPEE) on UVB-irradiated photodamage through the regulation of activator protein (AP)-1, phosphoinositide 3-kinase (PI3K)/Akt, and mitogen-activated protein kinase (MAPK) signaling molecules in HaCaT cells. Methods : The cytotoxicity of PPEE on HaCaT cells was evaluated by the WST-1 assay. The 80 mJ/cm² of UVB (312 nm) was irradiated on HaCaT cells to induce the photodamage. Western blot analysis was conducted to investigate the protein expression levels of cyclooxygenase (COX)-2, matrix metalloproteinase (MMP)-9, and heme oxygenase (HO)-1 for ameliorative status by PPEE treatment in UVB-exposed HaCaT cells. In addition, the activated status of the inflammatory transcription factor, AP-1, as well as upstream signaling molecules, PI3K/Akt, and MAPK, were also evaluated by Western blot analysis. Results : Any cytotoxic effect was not induced at the concentration up to 200 ㎍/ml by PPEE treatment. Protein expression levels of COX-2 and MMP-9 were significantly down- and up-regulated by PPEE treatment. The inflammatory transcription factor AP-1, stimulated by UVB irradiation, was also significantly attenuated by PPEE treatment. The phosphorylated status of PI3K/Akt and MAPK were mitigated by PPEE treatment in UVB-exposed HaCaT cells. Moreover, PPEE treatment potently accelerated the expression of HO-1 and its transcription factor, nuclear factor-erythroid 2-related factor (Nrf)2, which is known for its anti-inflammatory activity. Conclusion : Consequently, PPEE treatment significantly regulated COX-2 and MMP-9 expressions in UVB-irradiated HaCaT cells. The inflammatory transcription factor AP-1, along with upstream signaling molecules PI3K/Akt and MAPKs, were also attenuated by PPEE treatment in UVB-exposed HaCaT cells. Additionally, PPEE treatment exaggerated HO-1 expression and Nrf2 activation, which might have contributed to the anti-inflammatory activity of PPEE. These results indicate that PPEE could be a candidate for attenuating UVB-induced photodamage in human skin.

• KSBB Journal
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• 제31권3호
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• pp.178-185
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• 2016

Aging of the face is mainly related to the features that are sagging or loss of elasticity of the skin by reducing the volume around the eyes or cheek. Intrinsic aging can be seen to cause thinner dermis, reduction of extracellular matrix and subcutaneous fat. This study was carried out to investigate the skin volume augmentation and anti-wrinkle effects of Tribulus terrestris fruit extract. Skin anti-aging effect of Tribulus terrestris fruit extract was evaluated by using lipid accumulation, expressin of type I procollagen and elastin in preadipocytes and human dermal fibroblasts. Tribulus terrestris fruit extract augmented preadipocytes differentiation about 56% at 100 µg/mL. The type I procollagen and elastin were increased about 35% and 25% by treatment 20% Tribulus terrestris fruit extract, respectively. The clinical study also showed that skin sagging, skin elasticity, and dermal density improved without adverse effect following 4 week application of cream containing 2% Tribulus terrestris fruit extract. We suggest that Tribulus terrestris fruit extract can have the good possibility as skin volume augmenting, skin elasticity and wrinkle improving agent.

• 한국자동차공학회논문집
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• 제19권3호
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• pp.106-112
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• 2011

This study is to investigate the effect of an aromatic content in high cetane number (CN) fuels on exhaust emissions under low temperature diesel combustion, which expands the previous research about an aromatic content in low CN fuels. A 1.9L common rail direct injection diesel engine was run at 1500 rpm 2.6 bar BMEP with four fuel sets: an aromatic content of 20% (A20) or 45% (A45) with CN30, i.e. low CN fuels, and CN55, i.e. high CN fuels. Given experimental conditions, the trend of exhaust emissions in high CN fuels was inconsistent with that of low CN fuels which all produced nearly zero smoke but higher NOx for the high aromatic fuel (CN30-A45). For high CN fuels, however, the low aromatic fuel (CN55-A20) produced lower smoke than the high one (CN55-A45) while NOx was similar to each other. The cause of this discrepancy between high CN and low CN fuels is unclear whether it comes from that CN may be a dominant factor to govern exhaust emissions rather than an aromatic content or that the actual CN value of CN55-A45 is lower than CN55-A20. More decent fuel matrix should be prepared and further experiments are needed to confirm it.

• Archives of Plastic Surgery
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• 제43권6호
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• pp.523-528
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• 2016

Background The use of acellular dermal matrix (ADM) in implant-based immediate breast reconstruction has been increasing. The current ADMs available for breast reconstruction are offered as aseptic or sterile. No published studies have compared aseptic and sterile ADM in implant-based immediate breast reconstruction. The authors performed a retrospective study to evaluate the outcomes of aseptic versus sterile ADM in implant-based immediate breast reconstruction. Methods Implant-based immediate breast reconstructions with ADM conducted between April 2013 and January 2016 were included. The patients were divided into 2 groups: the aseptic ADM (AlloDerm) group and the sterile ADM (MegaDerm) group. Archived records were reviewed for demographic data and postoperative complication types and frequencies. The complications included were infection, flap necrosis, capsular contracture, seroma, hematoma, and explantation for any cause. Results Twenty patients were reconstructed with aseptic ADM, and 68 patients with sterile ADM. Rates of infection (15.0% vs. 10.3%), flap necrosis (5.0% vs. 7.4%), capsular contracture (20.0% vs. 14.7%), seroma (10.0% vs. 14.7%), hematoma (0% vs. 1.5%), and explantation (10.0% vs. 8.8%) were not significantly different in the 2 groups. Conclusions Sterile ADM did not provide better results regarding infectious complications than aseptic ADM in implant-based immediate breast reconstruction.

• 대한치과교정학회지
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• 제50권6호
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• pp.391-400
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• 2020

Objective: Increased gingival elasticity has been implicated as the cause of relapse following orthodontic rotational tooth movement and approaches to reduce relapse are limited. This study aimed to investigate the effects of sulforaphane (SFN), an inhibitor of osteoclastogenesis, on gene expression in gingival fibroblasts and relapse after rotational tooth movement in beagle dogs. Methods: The lower lateral incisors of five beagle dogs were rotated. SFN or dimethylsulfoxide (DMSO) were injected into the supra-alveolar gingiva of the experimental and control group, respectively, and the effect of SFN on relapse tendency was evaluated. Changes in mRNA expression of extracellular matrix components associated with gingival elasticity in beagles were investigated by real-time polymerase chain reaction. Morphology and arrangement of collagen fibers were observed on Masson's trichrome staining of buccal gingival tissues of experimental and control teeth. Results: SFN reduced the amount and percentage of relapse of orthodontic rotation. It also decreased the gene expression of lysyl oxidase and increased the gene expression of matrix metalloproteinase (MMP) 1 and MMP 12, compared with DMSO control subjects. Histologically, collagen fiber bundles were arranged irregularly and were not well connected in the SFN-treated group, whereas the fibers extended in parallel and perpendicular directions toward the gingiva and alveolar bone in a more regular and well-ordered arrangement in the DMSO-treated group. Conclusions: Our findings demonstrated that SFN treatment may be a promising pharmacologic approach to prevent orthodontic rotational relapse caused by increased gingival elasticity of rotated teeth in beagle dogs.

• Journal of Electrochemical Science and Technology
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• 제13권2호
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• pp.213-226
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• 2022

In the present study, the corrosion behavior of aluminum Al-7075 tempered (T-6 condition) alloy was evaluated by immersion testing and electrochemical testing in 1.75% and 3.5% NaCl environment at acidic, neutral and basic pH. The data obtained by both immersion tests and electrochemical corrosion tests (potentiodynamic polarization and electrochemical impedance spectroscopy tests) present that the corrosion rate of the alloy specimens is minimum for the pH=7 condition of the solution due to the formation of dense and well adherent thin protective oxide layer. Whereas the solutions with acidic and alkaline pH cause shift in the corrosion behavior of aluminum alloy to more active domains aggravated by the constant flux of acidic and alkaline ions (Cl^- and OH^-) in the media which anodically dissolve the Al matrix in comparison to precipitated intermetallic phases (cathodic in nature) formed due to T6 treatment. Consequently, the pitting behavior of the alloy, as observed by cyclic polarization tests, shifts to more active regions when pH of the solutions changes from neutral to alkaline environment due to localized dissolution of the matrix in alkaline environment that ingress by diffusion through the pores in the oxide film. Microscopic analysis also strengthens the results obtained by immersion corrosion testing and electrochemical corrosion testing as the study examines the corrosion behavior of this alloy under a systematic evaluation in marine environment.

• Composites Research
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• 제22권3호
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• pp.60-65
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• 2009

본 인구에서는 탄소섬유강화 복합재 구조물의 실제 사용조건인 환경에 따른 기계적 특성 연구를 수행하기 위하여, $[0_6]_T$, $[90_{12}]_T$, $[0_{16}]_T$, $[{\pm}45]_{5S}$, $[0/9012/0]_T$, $[0/45/-45/45/-45/0]_{3S}$의 실험을 통해, 복합재의 강도와 강성을 측정 하였다. 실험 결과, 환경조건에서 복합재의 파손 거동을 파악하고 설계관련 데이터베이스를 확보하였다. 저은 건조 조건에서 강도의 증가는 저온($-55^{\circ}C$)에서 섬유 촉은 모재의 취성 증가의 요인으로 분석된다. 고온다습 조건의 진단강도와 전단탄성계수 감소는 침투한 수분에 의해 섬유와 모재의 결합부의 물성이 저하한 것으로 분석된다.

• 해양환경안전학회지
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• 제25권2호
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• pp.139-150
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• 2019

우리나라 해역에서 발생하는 해양사고 중 어선사고가 약 70 %를 차지하고 있음에도 불구하고, 대부분의 연구는 해양사고 전체를 대상으로 하고 있으며 단순히 사고 발생률에 대한 분석과 사고 발생 빈도를 줄이기 위한 대책 마련에 중점을 두고 있다. 그러나 효과적인 사고 저감 대책의 수립과 이를 실행하기 위해서는 정량적인 사고 위험도 예측 및 평가가 반드시 선행되어야 한다. 본 연구에서는 해양안전심판원의 최근 5년간의 어선사고 통계에 근거하여 9가지 사고유형에 대한 위험도를 연도별로 비교하였다. 또한 현재 우리나라의 경우 객관적인 위험도 평가기준이 없다는 점을 고려하여 이에 대한 대안으로 사고 유형별 사고 빈도와 사고 피해의 조합을 4사분면 상에 표시하는 2차원 사고 빈도-피해 매트릭스를 제안하고 이를 이용하여 사고 빈도와 사고 피해의 영향을 쉽게 확인할 수 있도록 하였다. 이러한 과정을 통한 위험도 평가 결과는 저감대책을 수립하고 안전대책을 마련하는 정책 제안자로 하여금 보다 다양하고 현실적인 사고 저감 대책을 마련하는데 도움을 줄 것이다. 또한 위험도 평가 매트릭스를 이용하여 각 사고유형에 대한 인적오류를 포함한 사고 원인의 상대적인 빈도 및 결과를 비교함으로써 사고 유형별로 원인에 따른 차별화된 위험 저감 대책을 수립할 수 있다.