• Mycobiology
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• 제39권1호
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• pp.12-19
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• 2011

Cellular damage caused by reactive oxygen species has been implicated in several diseases, thus establishing a significant role for antioxidants in maintaining human health. Acetone, methanol, and hot water extracts of Pleurotus citrinopileatus were evaluated for their antioxidant activities against ${\beta}$-carotene-linoleic acid and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals, reducing power, ferrous ion-chelating abilities, and xanthine oxidase inhibitory activities. In addition, the tyrosinase inhibitory effects and phenolic compound contents of the extracts were also analyzed. Methanol and acetone extracts of P. citrinopileatus showed stronger inhibition of ${\beta}$-carotene-linoleic acid compared to the hot water extract. Methanol extract (8 mg/mL) showed a significantly high reducing power of 2.92 compared to the other extracts. The hot water extract was more effective than the acetone and methanole extracts for scavenging DPPH radicals. The strongest chelating effect (92.72%) was obtained with 1.0 mg/mL of acetone extract. High performance liquid chromatography analysis detected eight phenolic compounds, including gallic acid, protocatechuic acid, chlorogenic acid, ferulic acid, naringenin, hesperetin, formononetin, and biochanin-A, in an acetonitrile and hydrochloric acid (5 : 1) solvent extract. Xanthine oxidase and tyrosinase inhibitory activities of the acetone, methanol, and hot water extracts increased with increasing concentration. This study suggests that fruiting bodies of P. citrinopileatus can potentially be used as a readily accessible source of natural antioxidants.

• 환경생물
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• 제22권4호
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• pp.507-512
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• 2004

This study was focused on the risk assessment of whether radiofrequency electromagnetic fields generated by mobile phone is cytogenetically toxic or not. We conducted the effects of 835-MHz electromagnetic field (EMF) on DNA strand breaks in mouse thymic lymphoma L5178Y $Tk^{+/1-}$ cells using alkaline comet assay. EMF frequency 835-MHz we chosen is one of the most popular communication frequency bands in Korean code-division multiple-access (CDMA) mobile phone system. The cells were exposed to 835-MHz EMF alone or 835-MHz EMF combined with cyclophosamide(CPA) or 4-nitroquinoline-1-oxide (4NQO) at specific absorption rate (SAR) of 4.0 W $kg^{-l}$ for 24 and 48hrs. DNA damage expressed as tail moment was increased more than two-fold after exposure to 835-MHz EMF for 24 and 48hr. In particular, CPA for 48hr and 4NQO for 24 hr enhanced notably the tail moment to 9-fold and 16-fold in the presence of 835-MHz EMF, respectively, compared to each single treatment. From these results, it appears that exposure to CDMA-mobile phone radiation at 835-MHz frequency may potentiate DNA strand breaks of mouse thymic lymphoma L5178Y $Tk^{+/1-}$;cells under the defined conditions of this study.

• 대한산업공학회지
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• 제41권4호
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• pp.352-358
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• 2015

It is important to guarantee the safety of vehicle to minimize the damage to the driver in case of the accidents. In order to inspect and later enhance the safety of vehicle, the owner of the vehicle usually have a vehicle safety inspection. The Korea Transportation Safety Authority (KOTSA) issues the Comprehensive Performance Inspection Certificate after vehicle inspection. The certificate only specify the legal inspection criteria for safety and measured values of the safety parameters, however, as ordinary driver in lack of expert knowledge about the vehicle is difficult to understand the contents of the Certificate. Thus, in this paper, the authors try to give the information about the inspection results in easier way to understand. This information not only guarantees the owner of the vehicle to better understand the inspection results, but it also gives the opportunity to the driver to deal with the specific problem listed in the results. The methods in this paper are to transform the vehicle inspection data into the non parametric distribution to easily represent the values to the index later on. Also, example indexes are presented to the actually inspected vehicle based on the reference distribution to show the better assessment of the developed method.

• Journal of Korean Neurosurgical Society
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• 제54권3호
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• pp.189-193
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• 2013

Objective : It remains debatable whether cervical spine fusion cages should be filled with any kind of bone or bone substitute. Cortical and subcortical bone from the anterior and posterior osteophytes of the segment could be used to fill the cage. The purposes of the present study are to evaluate the clinical outcomes and radiological outcomes including bone fusion and subsidence that occurred after anterior cervical discectomy and fusion using a stand-alone cage packed with local autobone graft. Methods : Thirty-one patients who underwent anterior cervical fusion using a stand-alone polyetheretherketone (PEEK) cage packed with local autobone graft from July 2009 to december 2011 were enrolled in this study. Bone fusion was assessed by cervical plain radiographs and computed tomographic scan. Nonunion was evaluated according to the absence of bony bridge on computed tomographic scan. Subsidence was defined as a ${\geq}2$ mm decrease of the interbody height at the final follow-up compared to that measured at the immediate postoperative period. Results : Subsidence was observed in 7 patients (22.6%). Of 7 patients with subsidence greater 2 mm, nonunion was developed in 3. Three patients with subsidence greater 2 mm were related with endplate damage during intraoperative endplate preparation. Solid bone fusion was achieved in 28 out of 31 patients (90.3%). Conclusion : With proper patient selection and careful endplate preparation, anterior cervical discectomy and fusion (ACDF) using a stand-alone PEEK cage packed with local autobone graft could be a good alternative to the standard ACDF techniques with plating.

• 대기
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• 제22권1호
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• pp.47-55
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• 2012

The characteristics of flow and pollutant dispersion for fire scenarios in an urban area are numerically investigated. A computational fluid dynamics (CFD) model coupled to a mesoscale weather research and forecasting (WRF) model is used in this study. In order to more accurately represent the effect of topography and buildings, the geographic information system (GIS) data is used as an input data of the CFD model. Considering prevailing wind, firing time, and firing points, four fire scenarios are setup in April 2008 when fire events occurred most frequently in recent five years. It is shown that the building configuration mainly determines wind speed and direction in the urban area. The pollutant dispersion patterns are different for each fire scenario, because of the influence of the detailed flow. The pollutant concentration is high in the horse-shoe vortex and recirculation zones (caused by buildings) close to the fire point. It thus means that the potential damage areas are different for each fire scenario due to the different flow and dispersion patterns. These results suggest that the accurate understanding of the urban flow is important to assess the effect of the pollutant dispersion caused by fire in an urban area. The present study also demonstrates that CFD model can be useful for the assessment of urban environment.

• 대한기계학회논문집A
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• 제34권12호
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• pp.1909-1915
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• 2010

고온의 연소가스에서 운전되는 국내 가스터빈 부품들은 매일 기동정지를 반복함으로써 열사이클에 의해 재료특성에 변화가 발생한다. 최근 많은 가스터빈 고온부품들이 단결정 초내열 합금으로 제작되어 지지만 재료열화 예측을 통한 부품 교체와 정비에 대한 기준이 없어서 대부분 제작사에 의존하고 있는 실정이다. 본 연구에서는 향후 수명평가와 손상분석의 기초자료로 활용하기 위해 실제 운전된 가스터빈 1 단 블레이드의 열화상태를 조사하였다. 사용한 블레이드는 25,000 및 52,000 의 등가운전시간(EOH : Equivalent Operating Hour)을 가졌으며, 재질은 단결정 초내열합금인 CMSX-4 이다. 사용된 블레이드에서 직접 시험편을 채취하여 기계적특성 시험 및 미세조직을 관찰하였다.

• 한국학교보건학회지
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• 제15권2호
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• pp.233-248
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• 2002

Purpose : Sexual abuse especially in younger group have been growing. This study was performed to propose the fundamental data for developing early education program to prevent damage from sexual harassment in elementary school students. Method : Questionnaire survey on cognitions and experiences about sexual harassment was done on 3125 elementary school students from seven elementary schools in Busan area from January to March, 2002. Data analysis was done with SPSS (ver 10.0). Results : Though 82% of the students have ever herd about sexual harassment previously, but self assessment of 'well-known' was only 5%. About 40% of them have ever experienced audio-visual sexual materials mainly through PC (18%), media (14%), etc. And, 60% of them have ever educated about sexual harassment. In cognitions, they agreed 'unwanted touch', 'intentional showing his (her) own body', 'send lewd mails and pictures', but disagreed 'ask massage from aged', 'gaudy joke' as one of sexual harassment. In attitudes, 'no response', 'defense with friends and family', 'express unpleasantness apparently' were desirable pattern, instead, 'his (her) own responsibility', 'problem only between person concerned', 'neglect is the best way' were undesirable. About 24% of them have ever experienced at least one of the fifteen types of sexual harassment with major types of lewd mails pictures (11%), hugging (5%), ask massage (4.7%) and unwanted touch (3.3%). The experience by gender was higher in girls (25.0%) than boys (22.4%) with no statistical significance. The mean level of cognition and attitude out of one hundred was $70.3{\pm}28.1$ and $73.5{\pm}15.9$, respectively. The mean frequency of experience was $0.4{\pm}1.1$ times. The level of cognition and attitude was higher in girls, 6th graders, and in ever educated group (p<0.001). Conclusions : The cognition level of elementary school students about sexual harassment assessed considerable. And, they also experienced several types of sexual harassment, though not too much. Therefore, compatible education program let them able to protect themselves from sexual harassment should be developed and applied even in early school age.

• 한국안전학회지
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• 제35권2호
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• pp.100-110
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• 2020

Recently, the frequency of typhoon and torrential rain due to climate change is increasing. In addition, the upsurge in the complexity of urban sewer network and impervious surfaces area aggravates the inland flooding damage. In response to these worsening situations, the central and local governments are conducting R&D tasks related to predict and mitigate the flood risk. Researches on the analysis of inundation in urban areas have been implemented through various ways, and the common features were to evaluate the accuracy and justification of the model by comparing the model results with the actual inundation data. However, the evaluation procesure using available urban flooding data are not consistent, and if there are no quantitative urban inundation data, verification has to be performed by using press releases, public complaints, or photos of inundation occurring through 'CCTV'. Because theses materials are not quantitative, there is a problem of low reliability. Therefore, this study intends to develop a comparative analysis procedure on the quantitative degree and applicability of the verifiable inundation data, and a systematic framework for the performance assessment of urban flood analysis model was proposed. This would contribute to the standardization of the evaluation and verification procedure for urban flooding modelling.

• 한국측량학회지
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• 제23권3호
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• pp.239-249
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• 2005

우리나라는 비교적 지진의 안전지대라는 의식이 팽배하다. 따라서 지진이 발생할시의 대처 방안또한 미흡하다고 할 수 있다 그러나 해외의 사례를 살펴보면 지진에 대한 충분한 대비가 없다가 갑작스러운 재난으로 큰 피해를 입는 경우가 있다. 또한 우리나라의 지진 발생 사례를 조사해 본 결과 지진의 발발 횟수도 작지 않았다. 만약 이러한 지진이 서울과 같은 대도시에 일어난다면 그 피해는 매우 심각할 것이다. 그럼에도 불구하고 아직 우리나라는 지진에 대한 대책을 구체적으로 모색하는 것이 다른 나라에 비해 부족한 것이 현실이다. 본 연구에서는 지진에 대비해 GIS를 활용하여 다양한 요인으로 지진 위험도를 분석하였다. 지진 발생 시 위험 요인으로는 건물 도괴 위험도, 화재 위험도, 대피 위힘도 이렇게 세 가지 위험도에 대하여 분석하였으며 분석 방법은 다음과 같다. 먼저 지진에 의해 발생하는 건물 도괴, 화재, 대피의 어려움 등과 같은 대표적인 재해를 규정하였다. 다음으로 재해 위험 요소를 도출하기 위하여 토지이용 실태, 인구밀도, 건물유형, 도로구조 등을 정량화 하였고 이를 분석하여 위험도를 결정하였다. 또한 분석된 위험도를 기반으로 하여, 재해 발생의 최소화와 대비를 위한 개선 방안을 제시했으며, 활용의 예로 대피 시나리오를 구축하였다. 본 연구는 동대문구의 3개 동을 대상 지역으로 연구를 수행하였는데 향후 이러한 연구 방법을 활용하여 지역을 확대하며 지진에 대한 위험도를 사전에 도출한다면 지진이 발생하더라도 피해를 줄일 수 있으리라 기대된다.

• Earthquakes and Structures
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• 제11권4호
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• pp.629-648
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• 2016

This paper deals with 111 buildings built between 1962 and 1987, from various parts of the city of Osijek, for which, through the collection of documentation, a database is created. The aim of this paper is to provide the first steps in assessing seismic risk in Osijek applying method based on vulnerability index. This index uses collected information of parameters of the building: the structural system, the construction year, plan, the height, i.e., the number of stories, the type of foundation, the structural and non-structural elements, the type and the quality of main construction material, the position in the block and built-up area. According to this method defining five damage states, the action is expressed in terms of the macroseismic intensity and the seismic quality of the buildings by means of a vulnerability index. The value of the vulnerability index can be changed depending on the structural systems, quality of construction, etc., by introducing behavior and regional modifiers based on expert judgments. Since there is no available data of damaged buildings under earthquake loading in our country, we will propose behavior modifiers based on values suggested by earlier works and on judgment based on available project documentation of the considered buildings. Depending on the proposed modifiers, the seismic vulnerability of existing buildings in the city of Osijek will be assessed. The resulting vulnerability of the considered residential buildings provides necessary insight for emergency planning and for identification of critical objects vulnerable to seismic loading.