• Toxicological Research
• /
• 제20권3호
• /
• pp.225-232
• /
• 2004

The suitability of the single cell gel electrophoresis (SCGE) assay as a test for the monitoring of genotoxicity of aquatic environment was evaluated. The SCGE assay was employed to detect DNA damage induced in clam (Spisula sachalinensis) exposed to a direct mutagen, N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) or an indirect mutagen, benzo[a]pyrene (B[a]P). The cells of gill and digestive glands were isolated from clam by homogenization, which was the optimized cell dissociation method, and the level of DNA damage was assessed and expressed as mean tail length. In the gill cells, significant dose- and time-dependent increase was observed in the mean tail length at the concentration from 0.01 to 0.5 ppm MNNG for 96 h. The linear correlation between relative dam-age index (RDI) values was suggested to provide criteria of genotoxicity monitoring for direct acting mutagen. The dose- and time-dependent responses of the digestive glands cells were less sensitive than those of the gill cells. In contrast, the genotoxic response resulting from the exposure of 0.01～1.0 ppm B[a]P to clam revealed a higher sensitivity in the digestive glands cells than the gill cells. The comparison between the time profiles of genotoxic responses in clam and carp, the latter had been obtained in our previous study, indicated that the metabolism of genotoxic compounds in the two aquatic organisms were quite different each other. We conclude that the SCGE assay has the potential as a screening test for routine genotoxicity monitoring of aquatic organisms because of its higher sensitivity and simplicity.

• Korean Journal of Radiology
• /
• 제22권8호
• /
• pp.1300-1309
• /
• 2021

Objective: To assess the feasibility and reproducibility of pancreatic surface lobularity (PSL) quantification derived from abdominal computed tomography (CT) in a population of patients free from pancreatic disease. Materials and Methods: This retrospective study included 265 patients free from pancreatic disease who underwent contrast-enhanced abdominal CT between 2017 and 2019. A maximum of 11 individual PSL measurements were performed by two abdominal radiologists (head [5 measurements], body, and tail [3 measurements each]) using dedicated software. The influence of age, body mass index (BMI), and sex on PSL was assessed using the Pearson correlation and repeated measurements. Inter-reader agreement was assessed using the intraclass correlation coefficient (ICC) and Bland Altman (BA) plots. Results: CT images of 15 (6%) patients could not be analyzed. A total of 2750 measurements were performed in the remaining 250 patients (143 male [57%], mean age 45 years [range, 18-91]), and 2237 (81%) values were obtained in the head 951/1250 (76%), body 609/750 (81%), and tail 677/750 (90%). The mean ± standard deviation PSL was 6.53 ± 1.37. The mean PSL was significantly higher in male than in female (6.89 ± 1.30 vs. 6.06 ± 1.31, respectively, p < 0.001). PSL gradually increased with age (r = 0.32, p < 0.001) and BMI (r = 0.32, p < 0.001). Inter-reader agreement was excellent (ICC 0.82 [95% confidence interval 0.72-0.85], with a BA bias of 0.30 and 95% limits of agreement of -1.29 and 1.89). Conclusion: CT-based PSL quantification is feasible with a high success rate and inter-reader agreement in subjects free from pancreatic disease. Significant variations were observed according to sex, age, and BMI. This study provides a reference for future studies.

• 식물병연구
• /
• 제18권4호
• /
• pp.381-386
• /
• 2012

독도 생태 연구의 일환으로 2008-2009년 2개년간 독도의 토양을 채집하고 선충의 종류, 밀도, 식이습성군, 생태지수 등의 연구를 수행하였다. 독도에서 총 31종의 선충이 발견되었으며 평균 밀도는 $m^2$당 239,500마리(26,000-836,000)였고 biomass는 $103.9mg/m^2$(3.0-388.6)였다. 중요도는 Acrobeloides 속이 Prominence value(PV) 117.8로 가장 높았고 다음으로 Rhabditidae(PV = 81.9), Prismatolaimus(PV = 39.0), Aphelenchoides(PV = 31.4) 순이었다. Feeding Group별로는 세균성선충이 전체 선충 중에서 밀도로는 77%, biomass로는 62%를 차지하여 가장 중요한 그룹이었고 다음으로는 식물기생성선충과 식균성선충류였다. 동도 참소리쟁이에서 발견된 뿌리썩이선충은 신종으로 추정된다. 독도 선충의 생태적 분석 결과 Shannon and Wiener 지수(2.46), Simpson's diversity 지수(0.86), 종 균일도(0.73), 종 풍부성(1.30)을 볼 때 독도의 선충상은 종이 풍부하고, 다양한 것이 특징이며, 독도만의 독특한 생태계를 유지하고 있다고 하겠고 이것은 경작되지 않고 자연 그대로 보존된 원시적 환경의 특징이다. 이번의 조사 결과는 독도의 생태적 모니터링에 기초자료로 활용되어질 수 있을 것이다.

• 한국항만경제학회지
• /
• 제36권4호
• /
• pp.93-106
• /
• 2020

무역은 국가 경제에 중요한 경제활동이다. 특히, WTO 출범 이후 2001년 중국의 WTO 가입, 다자간 무역체계의 확립, 자유무역협정(FTA) 등으로 무역의 범위가 확대되고, 국가 간 무역장벽의 완화 및 통합화로 인해 무역시장의 규모가 확대되고 있다. 그러나 무역시장 규모가 확대됨에도 불구하고, 2008년 글로벌 금융위기, 2016년 브렉시트, 2018년 미·중 무역전쟁과 같은 극단적인 사건 발생하여 무역시장이 직접적으로 타격받고 있다. 이에 본 연구는 무역활동을 대변하는 변수인 국제 해운 운임지수와 미국, 중국 무역 불확실성 사이의 의존구조를 분석 하였다. 분석 결과를 요약하면 다음과 같다. 첫째, 미국, 중국 무역 불확실성과 국제 해운 운임지수 조합의 결합분포가 각각 Frank copula, rotated Clayton copula 270°으로 나타나, 미국, 중국 국가별로 동일한 분포 구조를 보이는 것으로 나타났다. 둘째, Kendall's tau 상관관계를 살펴보면, 국제 해운 운임지수와 미국, 중국 무역 불확실성 사이에 음(-)의 의존성을 갖지만, 의존성 정도는 중국 무역 불확실성과 국제 해운 운임지수의 조합에서 더 크게 나타났다. 즉, 전 세계 수요와 무역 불확실성의 의존성은 미국보다 중국이 더 강하다는 것을 확인하였다. 마지막으로, 꼬리 의존성 결과를 살펴보면, 미국, 중국 무역 불확실성과 국제 해운 운임지수가 서로 독립적인 관계로 나타났다. 이는 무역 불확실성의 극단적인 사건 혹은 국제 해운 운임지수의 극단적인 사건이 발생해도 서로 영향을 받지 않는 것으로 의미한다.

• 대한기계학회논문집A
• /
• 제39권11호
• /
• pp.1123-1129
• /
• 2015

자동차부품 세척장비는 엔진과 변속기 블록 등의 가공과정에서 잔류하는 기름때를 제거하며, 잦은 수류방향 전환과 고압수의 분사를 위해 한 쌍의 2 방향 밸브를 사용한다. 그러나 정교한 밸브제어장치 없이 2 방향 밸브를 사용하는 경우 급격한 수류방향 전환에 따른 맥동현상이 발생하여 사용에 어려움이 따른다. 대안으로 하나의 3 방향 절환밸브를 사용하는 방법은 정교한 제어장치 없이도 정확한 수류방향 절환이 원활히 이루어져 이러한 문제점을 해결할 수 있다. 그러나 복잡한 유로 및 바텀플러그 형상으로 인해 유속변화가 심하게 발생하여 공동현상이 나타날 수 있다. 본 연구에서는 3 방향 절환밸브 내의 유동특성을 해석적으로 평가하였으며, 바텀플러그 하부에서 나타나는 공동현상을 공동화지표와 POC(Percent of cavitation)를 도입하여 정량화하였다. 공동현상의 저감을 위해 바텀플러그 형상을 매개변수화하고, 해석의 수렴성 개선과 해석시간을 단축시킬 수 있는 단순 유한요소모델을 이용하여 유동해석을 통한 형상최적설계를 실시하였다. 완전요인배치법을 통한 실험계획법과 인공신경망 기반 반응표면모델을 적용하여 공동현상이 발생하지 않는 POC 가 30% 미만인 바텀플러그의 형상을 제시하였다. 얻어진 최적해는 POC 27%에 대하여 바텀플러그의 허리길이와 꼬리길이가 각각 6.42mm 및 6.96mm 이다.

• 한방안이비인후피부과학회지
• /
• 제22권1호
• /
• pp.76-88
• /
• 2009

Back ground and Objective : There is a need for objectification and scientific verification of Pattern identification in Oriental medicine. The purpose of this study was to investigate the skin characteristics of Qi deficiency and Blood deficiency animal models. Material and Methods : Sprague-Dawley rats were divided into three groups: normal group, Qi deficiency group and Blood deficiency group. The Qi deficiency animal model was induced through restriction of food (75g/kg/day) for 20 days. Blood deficiency animal model was induced by bleeding from tail vein(0.3 ml/time) 8 times. The normal animal model was kept without any intervention. The general condition was observed by measuring body weight, body temperature, blood pressure, pulse rate, and hematological and biochemical parameters. The skin characteristics were observed by measuring the erythema index(EI), melanin index(Ml), transepidermal water loss(TEWL) and dermal microcirculation. Results : 1. In the Qi deficiency group, body weight was lower than the other groups. In the Qi deficiency group, blood pressure was lower than in the Normal group. There was no difference in body temperature and pulse rate between the three groups. 2. In the Qi deficiency group, blood sugar was lower than in the Blood deficiency group. There was no difference in triacylglycerol between the three groups. In the Qi deficiency group, the WBC count was lower than in the Blood deficiency group. RBC count was highest in the Qi deficiency group, Normal group and Blood deficiency group respectively. In the Qi deficiency group, Hb and Hct were higher than the other groups. 3. EI and MI were decreased in the Qi deficiency group, and EI showed a significant decrease. 4. EI and MI were increased in the Blood deficiency group, and MI showed a significant increase. 5. TEWL was significantly increased in the Qi deficiency group, while it was decreased in the Blood deficiency group, TEWL was highest in the Qi deficiency group, Normal group and Blood deficiency group respectively and all three groups showed significant difference. 6. In the Qi deficiency group, dermal microcirculation was lower than the other groups. Conclusion : The above results show that the erythema index decreases in the Qi deficiency model, and the melanin index increases in the Blood deficiency model. The Qi deficiency animal model shows an increase in transepidermal water loss, while the Blood deficiency animal model shows a decrease. Further studies should develop new models of Pattern Identification that are more specific.

• 한국수정란이식학회지
• /
• 제28권4호
• /
• pp.325-335
• /
• 2013

The study was set for one year to measure the effects of concentrate supplementation on reproductive performances and semen quality in indigenous rams. The study was conducted at the Department of Surgery and Obstetrics, Faculty of Veterinary Science, Bangladesh Agricultural University, Mymensingh, Bangladesh during the period from May 2011 to April 2012. Forteen ram lambs (4~5 months) were randomly divided into two equal groups (n=7); supplemented vs control. The animals of control group were maintained on natural grazing. Along with natural grazing the supplemented group was on supplemented feeding. The concentrate supplementation (Wheat bran, Crushed maize, Soy bean meal, Fish meal, DCP powder, Vitamin mineral premix, Salt) was provided @ 300 g/head /day to the supplemented group. Body weight, scrotal circumference, BCS and libido index were measured weekly. Age, body weight and scrotal circumference at puberty were recorded. Semen was collected once in a weak using artificial vagina and chilled at $5^{\circ}C$ for 48h for evaluation. Concentrate supplementation did not influence (p>0.05) body condition score, age, weight, scrotal circumference at puberty and libido index. Final body weight (kg), growth rate (g/d), scrotal circumference (cm) and scrotal growth rate (mm/15d) were significantly (p<0.05) higher in supplemented group of rams compared to control. Volume, concentration, motility and membrane potentiality of spermatozoa were varied significantly (p<0.05) in supplemented and control groups. However, density, mass motility, viability and sperm with normal acrosome, midpiece and tail were not differed insignificantly (p>0.05) in different observation times. It was concluded that concentrate supplementation with free grazing improved weight and scrotal circumference gain and semen production with increased quality in indigenous ram.

• Toxicological Research
• /
• 제11권1호
• /
• pp.37-42
• /
• 1995

Effect of cadmium on the early amphibian development was analyzed through FETAX (Frog Embryo Teratogenesis Assay: Xenopus). Embryos manifested concentration-dependent mortality and realformations; shortage of anterior-posterior axis gut realformation, ocular anomalies, bent notochord, misshapen dorsal fin, and derreal blisters. The treatment with 1.5ppm cadmium solution caused 100% mortality and concentration of lppm did not kill the embryos that caused 100% anomaly. The teratogenic index (TI = LC50 /EC50) was 2.8 indicating that $CdCl_2$ is teratogenic for Xenopus laevis. Embryos that were pulsetreated with at early to late blastula stage (St. 3-9) and mid to late blastula stage (St. 6-10) showed relatively strong resistance to cadmium, but the embryos treated at gastrula stage (St. 10-13) showed high mortality. And the embryos treated at tailbud stage (after St. 25) showed highest mortality of any other early stages. Effects of temperature were studied through pulse- treatment during gastrula stage at $20^{\circ}C$ and $30^{\circ}C$. The embryos treated with 7.5ppm at $30^{\circ}C$ and 15ppm at $20^{\circ}C$ caused 100% mortality respectively, indicating that higher temperature had more severe toxic effect. One of the most peculiar effect of cadmium at gastrulation was distortion of the tail. The probable cause of toxic effect of Cd was discussed.

• 응용통계연구
• /
• 제23권4호
• /
• pp.651-668
• /
• 2010

금융 포트폴리오의 두 위험측도인 VaR와 ES에 대한 여러 추정방법을 1일 후와 10일 후의 경우로 나누어 각각 비교하였다. 2008년 미국발 세계 금융위기 기간을 포함한 KOSPI 자료와 해외 5개국의 종합주가지수 자료를 이용하여 실증적으로 비교하였다. 손실 분포의 두터운 꼬리와 조건부 이분산성을 동시에 고려하는 방법을 중심으로 여러 방법을 추가적으로 고려하였고, 국내 자료에 어떤 방법이 적절하며 종합적인 성능은 어떤가를 살펴보았다.

• Fisheries and Aquatic Sciences
• /
• 제6권2호
• /
• pp.51-58
• /
• 2003

The gonadal development and the gametogenic cycle and the fine structure of ripe germ cells of the cultured Pacific oyster, Crassostrea gigas were investigated using oysters monthly collected from the southern coast of Korea from October 2000 to September 2001. Monthly changes in the condition index were similar to that of meat weight rate and the highest value was observed in between April and May, and the lowest value in August. The external colors of the testis and the ovary were milky white and yellowish, respectively. The spawning period of the Pacific oyster was continued from May to September, with a peak in July. The gametogenic cycle could be classified into five successive stages: multiplicative stage (December to March), growing stage (March and April), mature stage (April to June), spawning stage (June to August) and resting stage (August to January). Variety of egg yolk granules, lipid granules, mitochondria, and endoplasmic reticula were observed in cytoplasm of ripe oocyte. The spermatozoon consisted of the head, middle piece and tail; including cap-shaped acrosome with domed structure, elliptical shaped nucleus, four mitochondria, two centrioles and flagellum.