• Toxicological Research
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• 제19권2호
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• pp.123-131
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• 2003

This study was carried out to assess the combined repeated dose, reproduction and developmental toxicities of benzoyl peroxide for OECD SIDS (Screening Information Data Set) program. Male and female Sprague-Dawley rats were exposed to benzoyl peroxide at dose levels of 0, 250, 500 and 1,000 mg/kg/day for 29 days for males and for 41-51 days for females. No deaths were found in all animals including control group during exposure period. No hematological effects attributable to benzoyl peroxide were observed in all treated groups. Significant decrease in the weight of testes and epididymis were observed in males at 1,000 mg/kg/day. In females at 1,000 mg/kg/day, slight histopathological effects in uterus such as epithelial vacuolation or hyperplasia were observed. No treatment-related changes in precoital time and rate of copulation, fertility and gestation period were noted in all treated groups. There was no evidence of teratogenic effect of benzoyl peroxide, but body weight of pups at 1,000 mg/kg/day was significantly decreased. NOAEL for combined repeated dose and reproduction/developmental toxicity was 500 mg/kg/day.

• 대한가정학회지
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• 제49권5호
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• pp.11-22
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• 2011

This study aimed to suggest more appropriate and accurate festival costumes based on a comparative analysis on various reproduced costumes and a period review of traditional festival costumes. In particular, the comparative analysis examined festival costumes which appeared in Korean and Japanese festival parades during the Baekje Period. The Baekje Cultural and Sacheonwangsawasso Festivals were examined. A literature review as well as field research and digital restorative techniques were used in the study. The reproduction patterns of Baekje costumes from both festivals were compared with original Baekje costumes, demonstrating several differences in the configuration, material, color, and shape of the costumes in addition to the way they were worn. Based on the comparative analysis, Baekje costumes used in Festivals were grouped into three categories: King's Costume, Queen's Costume, and Government Official's Costume. Dress sketches and 3D illustrations also have been presented.

• 한국전문물리치료학회지
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• 제14권3호
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• pp.16-22
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• 2007

The purpose of this study was to determine the influence of muscle fatigue in elbow flexors on the sense of force reproduction. Fifteen healthy subjects were recruited for this study. Maximum voluntary force (MVF) of elbow flexor muscles was measured by a digital tensiometer. Force errors were measured to test accuracy of the sense of force reproduction in elbow flexors. The subject was required to flex the elbow joint, to maintain and concentrate on about 20% of the MVF target force under visual feedback for 3 seconds. After a 5 second period rest, the subject was asked to duplicate the target force actively. Muscle fatigue was evoked with isometric contraction of the elbow flexors. Isometric contraction was continued until a 50% drop in MVF. The difference, in kilogram between the target force and the reproduced force was calculated for measuring force error. Force errors were compared between the non-fatigued condition and the fatigued condition by the paired t-test. Force errors were significantly increased in the fatigued condition compare to non-fatigued condition. This result suggests that the sense of force reproduction can be disturbed by localized muscle fatigue.

• 농촌의학ㆍ지역보건
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• 제47권2호
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• pp.61-66
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• 2022

Objectives: In the epidemiology of communicable diseases, the term epidemic period, also referred to as "wave" is often used in the general and academic milieu. A wave refers to a natural pattern of increase in the number of sick individuals, a defined peak, and then a decline in the number of cases. It implies a pattern of peaks and valleys after a particular peak is taken. The idea of epidemic waves is a useful tool for predicting the course as well as helping to accurately describe an epidemic. However, in many domestic and foreign news as well as in various research results in Korea, most of the reports either had no standard, were inaccurate, had a questionable classification of the period of the epidemic, or the basis for classification of a given wave was not presented. Methods: The author reviewed and organized related literature with epidemic wave. The author made several suggestions of an epidemic wave as follows. Results: To start with, it should be based on the number of incident cases in consideration of the size of the outbreak, then the period from the bottom to the peak and then reaching the next bottom; also, the period over a certain scale based on the number of incident cases; and the period according to the change in the major infection type (mutation-dominant species). In addition, according to the period of change in the vaccination rate (formation of herd immunity), as well as the content and duration of the intervention, that is, classification according to the applied quarantine stage. Furthermore, the classification of epidemic periods by the time-dependent reproduction number or time-varying reproduction number (Rt), and lastly the application of mathematical methodology. Conclusions: Therefore, classifying the epidemic period into generally known and accepted time frames is considered to be a very important task for future research analysis and development of intervention strategies.

• 한국해양학회지:바다
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• 제5권3호
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• pp.186-194
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• 2000

본 연구에서는 중규모 해양모형을 이용하여 주어진 한반도 주변 대기경계조건에 대한 해양모형의 반응을 연구하였다. 연구는 크게 스핀업(spin-up) 실험과 재현(reproduction) 실험으로 나뉘는데, 스핀업 실험은 해양모형을 스핀업시켜 기후학적 월평균 해양상태로 유도하는 실험으로 월평균 대기상태를 경계조건으로 하여 해양모형을 장기적분하였다. 재현 실험은 1980년${\sim}$1998년 동안(19년)의 한반도 주변 해역의 해양변동을 재현하고자 한 실험으로 이를 위하여 스핀업 마지막 해의 해양상태를 모형의 초기상태로 하고 그 기간 동안의 월평균 기상 자료를 경계조건으로 해양모형에 적용하여 19년간 적분하였다. 스핀업 실험에서 모형은 동해지역에서의 동한 해류의 이안, 극전선대(polar front)형성 그리고 소규모 에디들에 의한 냉수대의 형성과 황해지역에서의 연안역과 중앙부 사이에 남북으로 형성되는 수온전선 대 그리고 역풍류(Upwind Current)의 변화에 기인한 순환 구조의 계절적인 변동 등 한반도 주변해역에서 나타나는 특징적인 순환들을 잘 모사하였다. 또한 1982${\sim}$98년까지에 대한 재현 실험에서는 주어진 대기 경계조건에 따른 해면온도의 변동성과 기간동안 약 0.5$^{\circ}$C의 해면온도 아노말리의 상승을 관측과 유사하게 모사하였다. 따라서 실험은 모형이 주어진 경계조건에 대하여 해양의 평균적인 상태 뿐만 아니라 변동성도 잘 모사하고 있음을 보여주었다.

• 한국식품영양과학회지
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• 제7권1호
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• pp.19-23
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• 1978

1. 식물(植物)의 크기에 따라서 저온(低溫)의 날극감응(剌戟感應)을 달리하였다. 2. 유식물시대(幼植物時代)에 있어서 단기간(短期間)의 저온(低溫)의 영양이 추태개화(抽苔開花)를 빠르게 하였다. 3. 저온처리후(低溫處理後)의 추태개화촉진(抽苔開花促進)의 현상(現象)은 성숙식물(成熟植物)보다도 유식물(幼植物)에 있어서 더 크고 특히 발아직전기(發芽直前期)가 가장 현저(顯著)하였다. 4. 저온(低溫)에 처리(處理)한 유식물(幼植物)은 그 묘(苗)가 큰 것일수록 전생장기간(全生長期間)이 점차적으로 길어진 것을 볼 수 있었으나, 처리후(處理後)는 반대(反對)로 단축(短縮)되었다. 5. 유식물(幼植物)에 $4^{\circ}C$내외(內外)의 저온(低溫)으로 처리기간(處理期間) 17일(日) 전후(前後)에서 현저(顯著)한 개화촉진(開花促進)을 나타냈으나 성숙식물(成熟植物)은 40일이하(日以下)에서도 추태(抽苔)하지 않았다.

• 한국가축번식학회지
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• 제22권4호
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• pp.303-306
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• 1998

본 실험은 유우에 있어서 주간 분만유기에 대한 사료급여 시간의 영향을 검토하기 위하여 실시하였다. 본 실험결과 야간에 사료를 급여할 경우 87.8%(9＋15시간) 및 80.7%(12＋12 시간) 가 주간에 분만하였으며 08:00 시와 18:00 시에 사료를 급여할 경우 57.9%(9＋15 시간 ) 및 51.8%(12＋12시간) 가 주간에 분만 (p＜0.001) 하였으며 특히 주간분만 시 06:00∼11:00시에 38.5%, 16:00∼17:00 시에 19.6% 가 분만되었다.

• 한국가축번식학회지
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• 제17권3호
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• pp.209-220
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• 1993

This study was attempted to investigate the processes of regression of the corpus luteum and uterus after parturition in 2∼3 multiparous Korean native goats. The concentrations of LH, prolactin and progesterone in blood plasma of native goats were measured at 5 day intervals from 10 days prepartum to 35 days postpartum. The pregnancy corpus luteum from goats at Days(D) 1, 10, 20 and 30 days of postpartum were examined by light microscopy. Changes in the uterus fo goats were studies by macroscopic and light microscopic observations during the postpartum period. Mean concentrations of plasma LH were low after parturition and the levels of plasma LH were similar during late gestation and throughout the postpartum period. Mean plasma concentrations of prolactin were 0.30 0.06 and 0.38 0.13ng/ml at Day 5 and Day 10 prepartum, respectively, but PRL levels remained slightly high for 5 weeks after kidding. Mean levels of progesterone in plasma were 0.33 0.05ng/ml on Day 1 postpartum(P<0.01). Through light microscopic survey, pregnancy corpora lutea were quite degeneration by day 10 pospartum. Microscopic changes of CL regression consisted of cytoplasmic eosinophilia and vacuolation, and pyknosis and karyorrhexis of the nucleus of luteal cells. Vascular changes were distended at the periphery ofthe CL. From macroscopic measurements of the uterus, the uteri were returned to their initial non-pregnant stage within a period of 21 dyas after parturition. Following partuition the intercaruncular epithelium was reparied by 20 days. The uterine epithelium was partially recovered in the carucle by 30 days postpartum.

• 한국발생생물학회지:발생과생식
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• 제25권4호
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• pp.299-303
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• 2021

The ascidian Halocynthia aurantium (sea peach), a marine invertebrate, belongs to the same genus of the phylum Chordata along with the ascidian Halocynthia roretzi (sea pineapple), which is one of the model animals in the field of developmental biology. The characteristics of development and reproduction of H. aurantium are not yet known in detail. In order to find out the spawning period of H. aurantium, we investigated development of the gonads during the annual reproductive cycle. Testis and ovary were both in the bisexual gonads (ovotestes) of H. aurantium, which is a hermaphrodite like H. roretzi. In H. aurantium, the right gonad was longer and slightly larger than the left gonad throughout the year. In each gonad, the number of the testis gonoducts was slightly higher than that of the ovary gonoducts. These features were similarly observed in H. roretzi. However, the number of the testis gonoducts and the ovary gonoducts in each gonad of H. aurantium was about half that of H. roretzi. The gonads of H. aurantium contracted during the winter and summer seasons. The gonads decreased to the smallest size around February, and then started to increase again in March. The gonads were most developed in September of the year. Therefore, it is estimated that the spawning of H. aurantium begins around this period.

• Journal of Preventive Medicine and Public Health
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• 제53권6호
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• pp.405-408
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• 2020

In epidemiology, the basic reproduction number (R₀) is a term that describes the expected number of infections generated by 1 case in a susceptible population. At the beginning of the coronavirus disease 2019 (COVID-19) pandemic, R₀ was frequently referenced by the public health community and the wider public. However, this metric is often misused or misinterpreted. Moreover, the complexity of the process of estimating R₀ has caused difficulties for a substantial number of researchers. In this article, in order to increase the accessibility of this concept, we address several misconceptions related to the threshold characteristics of R₀ and the effective reproduction number (R_t). Moreover, the appropriate interpretation of the metrics is discussed. R₀ should be considered as a population-averaged value that pools the contact structure according to a stochastic transmission process. Furthermore, it is necessary to understand the unavoidable time lag for R_t due to the incubation period of the disease.