• Toxicological Research
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• 제16권1호
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• pp.27-31
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• 2000

Recently, there is a worldwide concern that a great number of man-made chemicals have a hormone-like action both in humans and in animals. EPA and OECD are developing screening programs using validated test systems to determine whether certain substances may have an effect on humans. In the present study, the establishment of in vivo short-term test system for pubertal female assay with thyroid to detect endocrine disrupting chemicals was tried using a model substance, methoxychlor (MC), a chlorinated hydrocarbon insencticide. Forty female rats were assigned to four groups. MC was administered at dose levels of 0, 8, 40 and 200mg/kg by gavage to female rats from day 21 post partum to the completion of vaginal opening. We evaluated body weight change, age at vaginal opening, onset of estrous cyclicity, age at first esturs, ovary weight, and serum concentrations of thyroxine and thyroid stimulating hormone in female rats. The age at vaginal opening of females receiving 40 200mg/kg was significantly younger than control. The onset of estrus cyclicity and age at first estrus of females receiving 200mg/kg was also younger than controls. There was no effect of treatment on body weight, ovary weight, and hormone concentration. Based on these results, it can be concluded that application of MC at dose level of 40mg/kg affects the vaginal opening and application of MC at dose level of 200mg/kg accelerates the vaginal opening and the onset of estrus cylicity.

• 한국발생생물학회지:발생과생식
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• 제12권1호
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• pp.9-18
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• 2008

현존하는 생물들은 주변 환경에서 오는 반복되는 신호의 영향을 받고 있다. 그 신호는 태양 및 지구의 운동 관계에서 되풀이되어 일어나는 주기적인 변화이다. 생식 및 번식, 세포 내 각종 분자들의 작용, 발생 단계에 일어나는 다양한 변화 등등의 생리학적/행동학적 활동들은 모두 일주기든 연주기든 주기성을 띠고 있다. 일주기 리듬을 통하여 생물들은 근본적으로 주변의 외부 시간에 그 생물 자체가 적응하게 하여, 일상적으로 반복되는 환경에서 적절한 시기에 활동하도록 하는 것이다. 각종 리드미컬한 패턴 중에 편승 변환을 고찰하기 위해 제시된 한계주기궤도에 초점을 맞추어 고찰하고자 한다.

• 한국임상수의학회지
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• 제32권2호
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• pp.168-173
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• 2015

본 연구는 젖소에서 산후 자궁염증 및 난소주기 회복 정도를 평가하였으며, 또한 분만 사고 및 산후 기간 질병 발생에 대한 조사를 위하여 실시하였다. 충청 지역 4개 젖소 목장의 사육 젖소 224두를 이용하였다. 자궁의 염증상태를 평가하기 위하여, 분만 후 8주까지 매주 메트리체크 기구를 이용하여 자궁분비물 중 농의 비율에 따른 성상을 점수화(메트리체크 점수; 0-5점) 하였으며, 분만 후 4, 6, 8주에는 백혈구 비율 산정을 위한 자궁세포 검사를 실시 하였다. 분만 후 난소주기 재개 여부 확인을 위하여 4, 6, 8주에 프로게스테론 농도(${\geq}1ng/mL$)를 분석하였다. 분만 후 메트리체크 점수는 1주($3.4{\pm}0.1$)부터 4주($2.0{\pm}0.1$)까지 연속적으로 감소하였으며(p < 0.0001), 이 후 8주까지 비슷한 점수를 유지하였다(p > 0.05). 자궁세포 검사를 이용한 호중구 비율은 분만 후 4주($22.3{\pm}1.8%$)에서 6주($12.1{\pm}1.4%$)까지 감소하였으며(p < 0.0001), 이 후 8주($9.2{\pm}1.4%$)까지 비슷한 비율을 유지하였다(p > 0.05). 난소주기 재개는 분만 후 2주(12.1%)에서 8주(74.3%)까지 연속적으로 증가하였다(p < 0.0001). 난산과 후산정체 발생 비율은 각각 20.5%, 30.4%였다. 분만 후 케토시스, 유열, 4위전위증, 패혈성 자궁염, 자궁내막염, 준임상형 자궁내막염, 자궁축농증 및 난소낭종 발생율은 각각 18.8%, 3.6%, 4.0%, 36.2%, 29.5%, 17.0%, 4.5%, 14.7%였다. 소화기 질병 및 유방염 발생율은 각각 5.4%, 9.6%였다. 도태 및 폐사율은 각각 4.0%, 3.6%였다. 난산, 후산정체, 패혈성 자궁염, 자궁내막염, 난소낭종, 소화기 질병, 유방염 및 도태율은 목장간 차이가 있었다(p < 0.05, p < 0.01). 결론적으로, 분만 후 4주에서 8주까지 자궁염증 상태 및 난소주기 재개 확인은 축군의 번식위생 유지에 도움을 줄 수 있는 임상적인 수단으로 사용될 수 있으며, 조사 지역에서의 젖소에서 난산, 후산정체, 패혈성 자궁염 및 자궁내막염의 발생율이 높았음을 보여 주었다.

• Journal of Communications and Networks
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• 제10권3호
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• pp.239-252
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• 2008

For orthogonal frequency division multiplexing (OFDM), cyclic prefix (CP) should be longer than the length of channel impulse response, resulting in a loss of bandwidth efficiency. In this paper, we describe a new technique to restore the cyclicity of the received signal when the CP is not sufficient for OFDM systems. The proposed technique efficiently restores the cyclicity of the current received symbol by adding the weighted next received symbol to the current received symbol. Iterative CP reconstruction (CPR) procedure, based on the residual intersymbol interference cancellation (RISIC) algorithm, is analyzed and compared to the RISIC. In addition, we apply the CPR method to Alamouti space-time block coded (STBC) OFDM system. It is shown that in the STBC OFDM, tail cancellation as well as cyclic reconstruction of the CPR procedure should be repeated. The computational complexities of the RISIC, the proposed CPR, the RISIC with STBC, and the proposed CPR with STBC are analyzed and their performances are evaluated in multipath fading environments. We also propose an iterative channel estimation (CE) method for OFDM with insufficient CP. Further, we discuss the CE method for the STBC OFDM system with the CPR. It is shown that the CPR technique with the proposed CE method minimizes the loss of bandwidth efficiency due to the use of CP, without sacrificing the diversity gain of the STBC OFDM system.

• 한국임상수의학회지
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• 제38권2호
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• pp.49-55
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• 2021

We aimed to identify the biological factors during the voluntary waiting period (VWP) that are associated with subsequent reproductive performance in dairy cows. Two hundred and one pregnant dairy cows had their body condition score (BCS) evaluated and blood samples taken 4 weeks before calving, at calving, and 1, 2, 4, 6, and 8 weeks after calving, to measure serum metabolite and progesterone concentrations. In addition, any peri- and postpartum disorders within 4 weeks of calving, and the mean milk yields 4 and 8 weeks postpartum, were recorded. The cows were allocated to two groups according to whether they had become pregnant or not by 120 days after calving: a pregnant group (n = 50) and a non-pregnant group (n = 151). Analyses of serum metabolite concentrations showed that the aspartate aminotransferase and γ-glutamyltransferase activities 2 weeks (p < 0.05) and the non-esterified fatty acid concentration 6 weeks (p < 0.01) postpartum were higher in the non-pregnant than in the pregnant group. However, the albumin concentrations between 2 and 8 weeks and the total cholesterol and magnesium concentrations between 4 and 8 weeks postpartum were lower in the non-pregnant group (p < 0.05). The BCS (p < 0.05) and percentages of cows that had resumed cyclicity (p < 0.001) by 6 and 8 weeks postpartum were higher in the pregnant than in the non-pregnant group, whereas the incidence of peri- and postpartum disorders was higher in the non-pregnant group (p < 0.05). In conclusion, high serum enzyme activities, which imply liver damage, imbalances in energy metabolites and magnesium, and a higher incidence of peri- and postpartum disorders, are associated with poorer reproductive performance, whereas high BCS and early resumption of cyclicity during the VWP are associated with superior reproductive performance in dairy cows.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2008년도 International Symposium on Remote Sensing
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• pp.80-83
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• 2008

Diverse researches using vegetation index have been carried out to monitor spring droughts that have frequently occurred since 2000. The strength of the drought monitoring using vegetation index lies in that it can reflect characteristics of satellite images: large area coverage, cyclicity, and promptness. However, vegetation index involve uncertainly caused by diverse factors that affect vegetation stress. In this study, multi-temporal vegetation index is compared with the most representative meteorological drought indices like PSDI, SPI. Based on the results from analyses, usability of vegetation index as a tool of drought analysis is proposed.

• Reproductive and Developmental Biology
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• 제30권3호
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• pp.213-218
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• 2006

본 연구는 젖소의 분만 후 난소 주기 재개의 이상이 번식 성적에 미치는 영향을 구명하기 위해 수행하였다. 정상적인 난소 주기가 진행이 되면 배란된 날에 난소 주기가 재개된 것으로 간주하였다. 공시우의 58.8%(l14/194)가 정상적인 난소 주기의 재개를 하였고 41.2%의 소에서 난소 주기의 재개가 지연되었다. 배란 후 황체기가 20일 이상 유지되는 난소 주기의 재개지연 I형(17.5%)과 분만 후 40일 이전에 첫 배란이 나타나지 않는 난소 주기의 재개지연 II형(22.7%)이 난소 주기 재개 지연의 일반적인 형태였다. 정상적인 난소 주기를 가진 개체와 비교해 보면, 황체기가 연장된 소들의 분만 후 100일 이내의 인공수정 공시율, 수태율과 임신율은 더 낮고(각각 84.2 대 40.0%; p<0.01, 24.0 대 21.4%, 20.2 대 11.1%) 분만 후 첫 수정 일수와 공태 일수가 더 길다(각각 $64.7{\pm}2.79$ 대 $105.7{\pm}7.48$일; p<0.01, $105.1{\pm}7.16$ 대 $133.7{\pm}11.17$일). 정상우와 무배란우를 비교해 보면, 100일 이내의 수태율과 임신율이 낮고(각각 24.0대 20.0%, 20.2 대 16.3%) 분만 후 첫 수정 일수과 공태 일수가 더 길다(각각 $64.6{\pm}2.79$ 대 $72.6{\pm}4.45$일, $105.1{\pm}7.16$ 대 $120.8{\pm}12.33$일). 결론적으로 젖소의 분만 후 비정상적인 난소 주기는 인공수정 공시율, 임신율, 첫 수정 일수와 공태 기간을 포함하는 번식 성적의 저하를 유발시킨다.

• 한국수정란이식학회지
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• 제32권3호
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• pp.177-182
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• 2017

본 연구는 암말의 계절에 따른 난소주기 변화를 분석하기 위해 수행하였다. 공시마는 국립축산과학원 난지축산연구소에서 사육 보유하고 있는 Jeju crossbred horses(더러브렛${\times}$제주마) 21두를 공시하였으며, 2016년 5월부터 2017년 6월까지 공시하였으며, 암말의 생식기 및 난소 초음파 검사는 주 1회 초음파 진단기를 이용하여 난소 내 난포 및 황체를 확인하였다. 공시마의 호르몬 분석을 위해 일주일에 2회 채혈하였으며 혈중 P4 농도를 분석하였다. 난소주기가 진행이 되면 배란된 날에 난소주기가 재개된 것으로 간주하였다. 총 21두의 공시마 중 13두(61.9%)만이 정상적인 난소주기를 보였으며, 공시마 8두(38.1%)는 난소주기가 지연되는 것을 확인할 수 있었다. 10월에 3두(16.7%), 11월에 5두(27.8%), 12월에 5두(27.8%)가 발정이 정지 되었으며, 나머지 5두(27.8%)에서는 겨울철에도 발정이 지속되는 것을 확인할 수 있었다. 발정이 정지된 개체는 이듬해 3월까지 발정이 정지되어 있었으며, 비번식계절에도 27.8%는 발정이 지속되었다. 18두 중 4월달에 11두(61.1%), 5월달에 2두(11.1%)가 발정이 재귀되었다.

• Journal of Animal Science and Technology
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• 제64권1호
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• pp.1-9
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• 2022

Equilume light masks had no impact on hastening the resumption of estrous cyclicity in mares maintained in outdoor pastures on the mainland of Korea due to the cold weather conditions. Jeju Island is a major horse-breeding site in Korea and is warmer than the mainland during the winter season. Therefore, the primary objective of this study was to explore the efficiency of the Equilume light mask on the resumption of seasonal estrous cycles in Thoroughbred mares on Jeju Island. A total of 20 nonpregnant mares were randomly divided into the Equilume light mask (n = 9) and stable lighting (n =11) groups. The experiment was performed at seven different horse-breeding farms located on Jeju Island from November 15, 2020, to February 15, 2021. The mares were exposed to the respective lights from 16:00 to 23:00. Follicle size and uterine edema were measured by ultrasound scanning. Body condition scores (BCS) were also monitored during the experiment. Statistical analysis was conducted using the SAS and SPSS software, and p-values of < 0.05 were considered statistically significant. Two of the nine (22.2%) mares in the Equilume light mask group and three of the 11 (27.28%) mares in the stable lighting group were still cycling in December and January, which were considered as all-year-round cycling mares. On February 15, there was no difference between groups in the resumption of early seasonal estrus cycle, which was determined by follicles > 25 mm in addition to uterine edema. All mares in the Equilume light mask group and five of the eight mares (62.5%) in the stable lighting group had resumed cycling. Interestingly, six of the seven mares (87.5%) in the Equilume light mask and four of eight mares (50%) in the stable lighting group had already ovulated on February 15 (p > 0.05), as determined by the presence of a recent corpus luteum. No difference was observed in BCS and uterine edema between groups (p > 0.05). In conclusion, the Equilume light mask can be an effective approach to induce early seasonal estrus cycles of mares in Jeju Island, and it also enhances the efficiency of farm management by reducing labor.

• Asian-Australasian Journal of Animal Sciences
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• 제10권2호
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• pp.229-232
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• 1997

Effects of short-term treatment with somidobove (recombinantly produced bovine somatotropin, BST) on estrous cyclicity and fertility were studied in dairy buffaloes. Twenty buffaloes of Nili-Ravi breed calving during the same season were assigned to either control (n=8) or treated group (n=12). The buffaloes of treated group received single infection (prolonged release) of 320 mg of somidobove on day-60 postpartum. The mean values for interval to first postpartum estrus, first service conception rate, services per conception, service period and calving interval for the treated group were 96.4 days, 66.7%, 1.70, 164 days and 473 days, respectively. The corresponding values for the control group were 92.5 days, 62.5%, 1.87, 135 days and 439 days. Means of all variables did not differ between control and treated group (p > 0.05). Three buffaloes of the control and four buffaloes of the treated group did not conceive at first service. Out of these, two buffaloes of control and one buffalo of treated group exhibited normal estrous cycles. It is concluded from these data that short term BST-treatment has no adverse effect on reproductive functions of dairy buffaloes.