There are an increasing number of reports that job related factors are associated with hypertension, sleep deprivation, obesity and diabetes. This study analyzed the relationship of working type, working hours and the prevalence of metabolic syndrome. The study’s subjects were 2,777 employees (1,446 males and 1,331 females) over 19 years old and their data was from the Korea National Health and Nutrition Survey (2015). The type of work was divided into day work and shift work. The working hours were divided into less than 40 hours, 40 to 49 hours, 50 to 59 hours and 60 hours or more per week. As a result of this study, the prevalence of metabolic syndrome was 26.4% of the males and 19.1% of the females. Generally there was no relationship between metabolic syndrome and type of work (day work and shift work). As a result of analysis of working hours and metabolic syndrome, the workers who worked 40-49 hr were associated with a decreased prevalence of metabolic syndrome as compared to that of workers who worked less than 40 hr (odds ratio: 0.47, 95% confidence interval: 0.24-0.95, p<0.05). Further, positive relationships were found between the number of work hours and the prevalence metabolic syndrome for specific females who worked over 40 hr/wk. It can be concluded from the results that it is important to help workers avoid metabolic syndrome through setting appropriate work hours.

Objectives: Lipoma is the most common soft tissue mesenchymal tumor which grows slowly. [1] [2] Intraoral lipomas are rare and have been reported in approximately 1 to 4% of all neoplasm in various literature. [2-5] Oral lipomas mostly develop slowly without symptoms, [6] and predominantly affect the buccal mucosa, floor of mouth, tongue and lip. [3] Material and Methods: A 71-year old male presented with asymptomatic swelling on tongue. On the clinical examination, there were various size of three swelling areas on the dorsum of tongue. Result: All lesions were surgically removed via intraoral approach under general anesthesia. They were soft and yellowish in color. All of the specimens has histologically revealed as typical lipomas. Conclusion: It is a report of tongue lipomas as a rare site, with clinical, histological and radiographic features. Also, there were several reports of a large or huge lipoma in oral cavity, however there were no report of multiple lipomas on the tongue. So, authors report the rarity of it.

복숭아유리나방(Synanthedon bicingulata)은 한국, 중국, 극동 러시아에 분포하며 벚나무류의 나무줄기 속으로 들어가 형성층을 섭식하여 피해를 준다. 유충의 영기를 조사하기 위하여 왕벚나무 나무줄기에서 시기별로 채집된 유충의 두폭을 측정하여 Dyar’s 법칙에 의해 영기 수를 추정한 결과 유충의 영기는 5령까지 존재하는 것으로 나타났다. 유충의 영기가 증가할수록 수피표면으로 부터의 유충 생육부위가 깊어졌으며, 월동유충의 영기는 주로 2령에서 3령의 어린유충으로 수피내에서 월동하는 것으로 나타났다.

세탄가는 경유의 품질기준 중 하나로써 디젤엔진에 사용되는 경유 연료의 착화성을 평가하는 항목이다. 세탄가 기준은 현재 자동차용 경유 기준으로 52 이상이며, 일반적으로 세탄가가 높으면 시동성이 좋고 운전이 원활해지나 지나치게 높으면 연소가 불균일해져 매연의 원인이 되고 연료소비량이 증가한다. 현재 국내의 품질시험방법에 규정되어있는 세탄가 측정방법은 CFR엔진을 이용한 세탄가분석, 경유의 밀도와 증류유출온도를 통하여 세탄가를 산출하는 세탄지수, CFR엔진의 단점을 보완하여 고온에서 연료의 연소되는 시간을 통해 세탄가를 측정하는 유도세탄가 등이 있다. 본 연구는 이러한 세탄가를 정유사별, 하·동절기별 시료를 확보하고 이를 분석하여 다양한 인자들에 의한 세탄가 측정방법의 상관관계에 대하여 분석하였다. 이를 통하여 세탄가, 유도세탄가, 세탄지수 순으로 세탄가가 높게 측정 되는 것을 확인하였고, 이를 통하여, 현재 편의성을 이유로 많이 사용되는 세탄지수로 인하여 세탄가 품질미달이 발생할 수 있기 때문에 이에 대한 추가 연구가 필요할 것으로 보인다.

In this study, we examined number, motility and plasma membrane integrity of spermatozoa from six regions of epididymis in bull. Six testicles with epididymides were castrated from six bulls (mean±standard error, age of days = 441.3±9.6, body weight (kg) = 367±8.4, scrotal circumference (cm) = 30.7±0.4) at Hanwoo Research Institute, NIAS and transported to laboratory within 1 hour. Testicular weight, length, width and circumference were recorded. Epididymis in each bull was randomly used for recovery of spermatozoa. Epididymis was divided into six regions: efferent duct (ED), caput, corpus, proximal cauda (Pcauda), distal cauda (Dcauda) and vas deferens (VD). In experiment 1, we examined sperm number of each region of epididymis. Each region of epididymis contained different number of spermatozoa: ED (37.8±15.7 × 106cells/ml, 8.2%), caput (93.6±18.8 × 106cells/ml, 20.2%), corpus (33.0±8.5 × 106cells/ml, 7.1%), Pcauda (104.2±23.5 × 106cells/ml, 22.5%), Dcauda (180.5±32.5 × 106cells/ml, 39.0%) and VD (14.0±5.0 × 106cells/ml, 3.0%). In experiment 2, sperm motility of each epididymal region was examined by computer assisted sperm analysis (SCA, MicroOptic) system. Sperm motility was divided into 4 groups (fast progressive, slow progressive, non-progressive and immotile) based on WHO guideline. Percentages of fast progressive of Pcauda and Dcauda (11.0±2.3 and 15.4±3.6%) were significantly higher than that of ED, Caput, Corpus and VD which is 0.1±0.1, 1.5±0.6, 1.9±0.7 and 0.3±0.2%, respectively (p<0.05). In experiment 3, percentage of intact plasma membrane spermatozoa of each regions were examined by hypoosmotic swelling test. Percentages of intact plasma spermatozoa were not significantly different among six regions of epididymis: ED, caput, corpus, Pcauda, Dcauda and VD which is 68.0±8.6, 74.0±5.3, 68.5±6.2, 70.8±5.5, 71.0±5.8 and 64.6±10.8%, respectively. In conclusion, in the present study, we found out distribution, motility and plasma membrane integrity of spermatozoa from six regions of epididymis in Hanwoo bull. These results will be contributed to basic research about spermatozoa transportation and characters in epididymis of bull.

Sonic hedgehog (Shh) signaling pathway plays a key role in the development of various vertebrate embryos and remains important in adults. Although Shh signaling pathway has widely been studied in post-implantation stage embryos, only few studies are reported about pre-implantation stage embryos. To investigate the effect of Shh on pre-implantation stage embryos, cyclopamine and purmorphamine were treated to embryos in culture. Cyclopamine acts as an antagonist of the hedgehog signaling because it has a high affinity to Smoothened, a key part of the hedgehog signaling pathway. On the other hand, purmorphamine activate Smoothened and acts as a Shh signaling agonist. The oocytes were collected after superovulation and parthenogenetically activated in Chatot, Ziomek, and Bavister medium (CZB) including 10 mM strontium for 5 hr. The activated oocytes were cultured in potassium simplex optimized medium (KSOM), KSOM with 5 uM of cyclopamine, KSOM with 1 uM of purmorphamine, or KSOM with both 5 uM of cyclopamine and 1 uM of purmorphamine. After 5.5 days in culture, there was no significant difference in blastocyst development among the four experimental groups. However, the hatching rate was increased in the groups containing purmorphamine, and the blastocysts of the purmorphamine-containing groups had higher total cell number than those of other two groups when the cells were counted after Hoechst33342 staining. Quantitative real-time PCR (qRT-PCR) shows the difference of gene expression level which are related to epithelial-mesenchymal transition (EMT). Taken together, this study suggests that the increase of Shh has an effect on the increases of EMT-related genes and hatching rate of pre-implantation stage embryos, and this may improve implantation subsequently.

Oak wilt disease caused by Raffaelea quercus-mongolicae is one of the serious diseases in Korea. Infected trees showed wilting and discolourations on the cambium when the bark of a tree is peeled, since it deters moisture migration. Raffaelea quercus-mongolicae is vectored by Platypus koryoensis. In this regard, it was assumed that there might be a positive correlation between the number of gallery generated by P. koryoensis and the level of damage on the infected tree by the oak wilt disease. In order to link the occurrence of dead oak trees with the number of galleries produced by P. koryoensis, five regions (Incheon, Anyang, Gwangmyeong, Icheon and Gimhae) were selected in Korea. The number of galleries on Mongolian oaks produced by attack of P. koryoensis was counted in four directions between 50cm and 100cm from the ground level. Furthermore, Vegetation was investigated from the area where the oak wilt disease occurred, and a data logger was set up to collect data including temperature and relative humidity in each region at the elevation between 100~200m. A significant difference was observed in the number of galleries made by the insect vector between dead trees and trees infected with oak wilt disease, while no difference was observed from the vegetation on the area investigated. We will further investigate as to whether climate factors might contribute to the density and the successful invasions of the insect vector to the oak trees.

Pine wilt disease caused by Bursaphelechus xylophilus has continued to expanding in Korea since its first occurrence identified from Busan in 1988. The direction of spread and density of two vector insects, Monochamus saltuarius and M. alternatus, are closely associated with the expansion and occurrence of pine wilt disease being observed in Korea. In 2016, a pheromone trap was installed to investigate the density of each vector. A correlation between the density of two insect vectors and the number of trees infected by pine wilt disease was further investigated in Gyeongnam, Gyeongbuk, Ulsan, and Jeju. To perform a correlation analysis, the number of infected trees was counted within a radius of 50m from which the pheromone traps were installed. In addition, factors that might have an effect on the density of vectors were investigated. This includes the altitude, temperature and forest type from the site where the pheromone traps were installed.

K-means algorithm is one of the most popular and widely used clustering method because it is easy to implement and very efficient. However, this method has the limitation to be used with fixed number of clusters because of only considering the intra-cluster distance to evaluate the data clustering solutions. Silhouette is useful and stable valid index to decide the data clustering solution with number of clusters to consider the intra and inter cluster distance for unsupervised data. However, this valid index has high computational burden because of considering quality measure for each data object. The objective of this paper is to propose the fast and simple speed-up method to overcome this limitation to use silhouette for the effective large-scale data clustering. In the first step, the proposed method calculates and saves the distance for each data once. In the second step, this distance matrix is used to calculate the relative distance rate (Vｊ) of each data j and this rate is used to choose the suitable number of clusters without much computation time. In the third step, the proposed efficient heuristic algorithm (Group search optimization, GSO, in this paper) can search the global optimum with saving computational capacity with good initial solutions using Vｊ probabilistically for the data clustering. The performance of our proposed method is validated to save significantly computation time against the original silhouette only using Ruspini, Iris, Wine and Breast cancer in UCI machine learning repository datasets by experiment and analysis. Especially, the performance of our proposed method is much better than previous method for the larger size of data.

Car-sharing is one of the most popular cases of a shared economy. It is a sustainable service that enhances mobility by renting shared vehicles to meet user's purpose in short-time. Car-sharing has known that it is effective in reducing ownership of passenger cars, reducing traffic congestion, and improving the environment. In Korea, a variety of car-sharing services have been launched, and since 2012, Korea Land & Housing Corporation (LH) has started to introduce HappyCar service for residents of public rental housing complexes nationwide. Public rental housing complexes have three types of complexes, one of which is complex for the low-income households. The purpose of this study is to find out the factors affecting the use of carsharing for low-income people using Poisson regression analysis with 2017 HappyCar usage data. Data including outliers was filtered and explanatory variables (age, sex, and accessibility of public transportation around rental housing complexes) were selected through correlation analysis. The results of this study are expected to be useful for analysis of carsharing low-income users' behavior, demand forecasting, and the establishment of shared transportation policies in the future.

본 논문은 3차원 축대칭 몰수체에 대해 소스 코드가 공개된 OpenFOAM 4.0을 이용하여 첫 번째 격자의 높이와 레이놀즈 수에 따른 마찰저항 변화에 대해 연구하였다. 마찰저항 계산을 위해 경계조건, 수치조건을 정립하였다. 축대칭 물체의 3차원 효과로 인해 거칠 기가 매우 작은 12 μΜ에서도 부드러운 표면과 비교해 마찰저항이 다르게 계산되었다. 레이놀즈 수가 커질수록 경계층의 두께 증가가 감소되었으며 이로 인해 마찰저항의 증가량이 감소되었다. 첫 번째 격자의 크기인 y+에 대한 영향에 대해서도 검토하였다. 첫 번째 격자가 log layer에 위치하고 있지 않으면 마찰저항과 표면의 전단력이 과도하게 예측되는 것을 확인하였다. 이는 경계층이 두껍게 예측되어 난류 에너지가 과도하게 예측되었기 때문으로 판단된다. 표면의 거칠기가 커질수록 경계층이 두꺼워지고 표면의 난류에너지가 증가되는 것을 확인하였다. 마찰저항을 정확하게 예측하기 위해서는 y+ 값, 거칠기 및 벽함수가 적절한 영역에 위치해야 함을 알 수 있었다.

본 연구는 방문객 유형별로 장성 편백치유의 숲(Jangseong Pyunbaek Healing Forest: JPHF) 내 ‘치유필드’의 이용객 수에 대한 지각(perceived number of users: PNU)과 이용객수에 대한 평가기준(evaluative standards)을 설정, 비교하기 위해 시행되었다. 2017년 9월 중 JPHF 내 ‘치유필드’ 이용객을 대상으로 편의표본추출 방법을 통해 선정된 158명의 표본으로부터 설문지기법을 이용하여 자료를 수집하였다. 치유필드 방문객 중 휴양객(일반 휴양을 목적으로 한 방문객) 은 49.3%, 치유객(건강 및 치유를 목적으로 한 방문객) 15.3%, 휴치객(휴양과 치유를 동일정도로 추구하는 방문객) 35.3%로 구성되어 있었다. 응답자가 지각하는 치유필드 이용객수는 전체적으로는 평균 23.8명(중앙값: 20.0명)으로 나타났으며, 방문객 유형별 평균범위는 21.1-27.8명(중앙값: 20.0명 동일)으로 조사되었다. 응답자의 PNU는 혼잡지각(perceived crowding: PC)(r=0.23) 및 치유경험 방해 지각(perceived interference of healing experience: PIHE) (r=0.20)과 낮은 상관관계를 나타냈다. 방문객 유형 간에 치유필드 적정이용객수(optimal number of users: ONU)는 차이가 없었다. 전체적으로 적정이용객수는 평균 28.9명(중앙값: 25.0명)으로 나타났으며 방문객 유형별 적정이용객수 범위는 평균 25.4-31.4명(중앙값: 25.0-27.5명)으로 분석되었다. 또한 최대 허용가능 이용 객수(maximum acceptable number of users: MANU)는 전체적으로 38.1명으로 나타났으며, 방문객 유형별로는 휴양객 36.9명, 치유객 32.0명, 휴치객 38.0명으로 각각 조사되었다. 방문객 유형별로는 MANU에 차이가 없었다. 응답자의 PC는 평균 2.73(SD: 3.26, 9점 척도), PIHE는 평균 3.26(SD: 1.77, 9점 척도)으로 나타났으며 방문객 유형별로는 휴치객이 휴양객에 비해 통계적으로 높은 PC와 PIHE를 보였다. PNU가 ONU를 초과한 그룹은 그렇지 않은 그룹에 비해 높은 PC와 PIHE를 나타냈다. 연구결과를 토대로 관리적 관점에서의 시사점을 제시하였으며 본 연구의 한계점과 추후 연구에 대하여 토의하였다.

목 적：확산강조 영상은 뇌질환 병변의 발견에 민감할 뿐 아니라 병변의 크기가 작아 발견이 어려울 때나 급성 및 아급성기의 뇌경색을 감별해 내는데 유용하게 사용된다. 그 밖에도 일반 MRI 검사로는 감별이 어려운 연부조직의 암과 양성종양을 확인 할 수 있어 근․골격계 검사에도 유용하게 사용된다. 하지만 해부학적 구조에 의해 자화감수성 차이 및 금속성 물질을 삽입한 환자에게서 EPI기법을 사용한 Diffusion 검사는 영상의 왜곡과 Artifact가 크게 나타나 영상에 대한 정확한 평가나 종양의 감별에 어려움을 겪게 된다. 이에 기존 Single-shot EPI 기법을 이용한 Diffusion검사에 비해 Metallic susceptibility artifact가 적은 IRIS Multi-shot Diffusion 기법의 SENSE factor와 Shot 수 변화에 따른 영상 변화를 확인하고자 하였다. 대상 및 방법：IRIS MS DWI 기법의 자기감수성 인공물과 기타 영상 평가를 위해 돼지고기에 실제 수술용 Metal pin을 삽입하여 인체와 유사한 Phantom을 제작하였다. 모든 검사는 IRIS MS DWI 기법을 이용 하여 Phantom 영상을 획득하였다. SENSE factor와 Shot 수의 변화에 따른 자기감수성 인공물의 왜곡 도 및 영상 변화를 확인하기 위해 SENSE factor 1, 2, 3, 4 값에 Shot 수를 각각 2, 4, 6으로 변화시켜 실험을 진행하였고 두 가지 Parameter를 제외한 모든 Parameter는 동일하게 적용하여 영상을 획득하 였다. 사용된 장비는 Philips medical system의 Ingenia 3.0T를 사용하였고, 신호수집 코일은 32 channel SENSE head coil을 사용하였고 모든 평가항목은 Infinitt healthcare사의 INFINITT PACS 를 이용하여 측정하였다. 자기감수성 인공물의 왜곡도 평가는 각 평가 영상에서 인공물의 가장 긴 종축 길이를 5회씩 측정한 후 평균값으로 산출하였고 정성적 평가는 5년 이상의 MRI 경력을 가진 전문방사선 사 5인이 항목 당 1회씩 측정한 후 평균값으로 산출하였다. 결 과：같은 SENSE factor 일 때 Shot 수의 증가로 자기감수성 인공물의 왜곡도는 감소하였다. 또한 같은 shot수 일 때 SENSE factor의 증가 시에도 자기감수성 인공물의 왜곡도는 감소하였다. 자화감수성인공 물 역시 SENSE factor와 Shot 수가 증가함에 따라 왜곡도의 정도가 감소하였으나 일정 Factor이상 후 에는 같은 값을 나타내었다. 전체적인 Image quality 평가에서는 Shot수의 변화 보다는 SENSE factor 의 변화시에 많은 영향을 주는 것을 알 수 있었고 과도한 SENSE factor 사용은 오히려 Image quality 가 저하 된다는 것을 알 수 있었다. Ghost artifact의 발생은 SENSE factor 4 이상이 되었을 때 발생하 였으며 이처럼 많은 SENSE factor의 사용은 Ghost artifact 발생시킬 수 있으므로 적절한 SENSE factor 사용이 필요할 것으로 생각된다. 결 론：본 연구에서는 IRIS MS DWI 기법의 SENSE factor와 Shot 수를 변화시켜 여러 가지 Artifact를 감소시키 고 Scan time을 단축시킬 수 있는 방안을 찾을 수 있었다. 더욱이 IRIS MS DWI 기법의 사용은 기존의 Single shot DWI 기법에서의 문제점들을 보완할 수 있었고 다양한 검사부위를 더 좋은 Image quality로 획득 할 수 있는 의미 있는 실험이었다. 앞으로 실제 임상에서 환자의 상태나 의뢰된 검사 목적에 따라 본 논문의 결과를 활용한다면 보다 진단적 가치가 높은 영상을 획득할 수 있을 것으로 사료된다.