• Reproductive and Developmental Biology
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• v.32 no.2
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• pp.89-95
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• 2008

The present study was undertaken to identify changes of plasminogen activators (PAs) in porcine oviductal epithelial cells (POECs) during the estrous cycle classified with post-ovulatory stages (Post-Ov), early to mid-luteal stages (Early-mid L) and pre-ovulatory (Pre-Ov) stages. The urokinase-type plasminogen activator (uPA) was only observed on day 5 and day 7 of culture in the POECs on all the estrous cycles and gradually increased according to increasing culture times, but not Early-mid L. In POECs-conditioned medium, uPA, tissue-type (tPA) and tPA-PA inhibitor (tPA-PAI) activity were observed at all culture times during estrous cycles. The uPA activity of POECs-conditioned medium on Post-Ov stage were significantly (p<0.05) decreased during prolonged cultures. On the other hand, the tPA activity of POECs-conditioned medium at Post-Ov stage was significantly (p<0.05) higher on day 5 than compared to the other days. Although was higher on day 1 at Post-Ov stage, the tPA-PAI activity of POECs-conditioned medium was significantly (p<0.05) higher on day 7 at all stage than that of day 5 of the culture. Taken together, these results suggest that uPA, tPA and tPA-PAI are produced by POECs, and the variations of the PAs activity are regulated in the different stages of the estrous cycle.

• Journal of the korean Society of Automotive Engineers
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• v.5 no.2
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• pp.48-55
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• 1983

The prediction of performance and emissions is presented for a spark ignition engine. a two zone, zero-dimensional model was employed which included thermodynamics, combustion and hear transfer, and a kinetic model employed for NOx. The model was used to analyze the processes of compression, combustion and expansion. Cylinder pressures and temperatures were calculated as a function of crankangle as well as engine performance and emissions. Predictions made with the simulation were compared with experimental data from a four cylinder spark ignition engine. Calculated pressures and, Co and Co$_{2}$ concentrations showed acceptable quantitative agreement with data. But calculated No concentrations were slightly different. A parametric study of the effect of variations in speed, combustion duration and spark timing was carried out. This simulation can be useful for design of spark ignition engines.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.15 no.4
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• pp.312-317
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• 2003

This paper describes an experimental study on small-scale sorption refrigerator. Silica gel (type A) as an adsorbent, HFC-l34a as a refrigerant were selected for a sorption refrigerator The focus of the design was to reduce the cycle time of the sorption refrigerator. Through the experiment, pressure and temperature variations in the adsorber were measured and the performance of refrigerator was predicted. In this paper, the small-scale sorption refrigerator operates with the cycle time of 4805. Its predicted cooling capacity is 25 W at -15$^{\circ}C$ and COP is 0.23.

• The Korean Journal of Malacology
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• v.11 no.2
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• pp.147-163
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• 1995

The unionid family Unionidae contains several genera in Korea, among which occru considerable variations in life histories and sexual conditions. Seven species from the Korea(Anodonta arcaeformis flavotincta, A. woodiana, Unio douglaseae, U. douglasiae sinuolatus, Lamprotula gottschei, Lanceolaria acrorhyncha, Solenaia triangularis)were stueide in order to identify and describe the seasonal gonadal activity and the visceral sex. The gonads of seven species were histologically examined by using the paraffin block technique for sectioning. All seven species were uniformly dioecious and testicular activity in six species except one species, S. triangularis, generated sperm-morulae(multinucleated cell). The annual reproductive cycle of the seven species could be classified into five successive stages; multicative, growing, mature, spent, deginerative and resting stages. The breeding season of six species was the summer and that of A. a. flavotincta was the winter.

• Korean Journal of Computational Design and Engineering
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• v.10 no.4
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• pp.284-292
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• 2005

This paper presents a new framework of kinematic tolerance synthesis and describes the implemented algorithm for planar mechanical systems comprised of higher kinematic pairs. Input to the synthesis algorithm is a parametric model of the mechanical system with allowed parameter ranges (tolerance ranges). The model is specified as the part profiles consisting of line and arc segments and the motion axes along which each part moves. The algorithm analyzes tolerance in generalized configuration space, called contact zones bounding the worst-case variations, and identifies bad system variations. The bad system variations then are removed out of the parameter ranges by adjusting the nominal parameter values if possible and then shrinking the ranges otherwise. This cycle is repeated until no more bad variations we found. I show the effectiveness of the algorithm by case studies on several mechanisms.

• Asian-Australasian Journal of Animal Sciences
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• v.22 no.5
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• pp.636-642
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• 2009

The corpus luteum (CL) is a transient endocrine gland that produces progesterone, a product required for the establishment and maintenance of pregnancy. In the absence of pregnancy, the production of progesterone in the CL decreases and the structure itself regresses in size. The life span and function of the CL are regulated by complex interactions between stimulatory (luteotrophic) and inhibitory (luteolytic) mediators. When an ovum is released from a mature follicle, angiogenesis and rapid growth of follicular cells form the CL. The purpose of the present study was to determine whether steroidogenesis, proliferation, and hypoxiarelated proteins are expressed in caprine CL. The expression of proliferating cell nuclear antigen (PCNA), vascular endothelial growth factor (VEGF), and hypoxia-inducible factor $1{\alpha}$ (HIF-$1{\alpha}$) were determined in caprine CL during the estrous cycle. Cytochrome P450 side chain cleavage protein did not vary significantly during the estrous cycle; however, there was an increased expression of $3{\beta}$ -hydroxysteroid dehydrogenase in the early and middle stages, which rapidly decreased in the late stage. The same observations were made with respect to steroidogenic acute regulatory protein. Variations in progesterone content and expression of PCNA, HIF-$1{\alpha}$, and VEGF were consistent with this result. Thus, the steroidogenic proteins, PCNA, HIF-$1{\alpha}$, and VEGF in caprine CL are dependent on the stage of the estrous cycle.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.9
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• pp.2009-2019
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• 2013

In this paper, we propose an automatic modulation recognition algorithm based on cyclic moment and new modified cumulant for analog and digital modulation signals. It is noteworthy that each modulated signal has different cycle frequency characteristics according to its order of cyclic moment. By means of this characteristics as classification features, various modulated signals can be efficiently classified. Also, to identify modulated signals having the same cycle frequency characteristics, we take advantage of the additional classification factors such as variations of envelope and phase as well as modified cumulant. The proposed algorithm was evaluated by considering the number of symbols, SNR, and frequency offset. In the simulation condition where the number of gathered symbols was about 819, and SNR and frequency offset were above 10dB and below 25%, respectively, the average accuracy of the proposed algorithm was more than 95%.

• Asian Journal of Atmospheric Environment
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• v.12 no.2
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• pp.109-126
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• 2018

This paper presents seasonal variation of $PM_{10}$ over five urban sites in Sabah, Malaysia for the period of January through December 2012. The variability of $PM_{10}$ along with the diurnal and weekly cycles of CO, $NO_2$, $SO_2$, and $O_3$ at Kota Kinabalu site were also discussed to investigate the possible sources for increased $PM_{10}$ concentration at the site. This work is crucial to understand the behaviour and possible sources of $PM_{10}$ in the urban atmosphere of Sabah region. In Malaysia, many air pollution studies in the past focused in west Peninsular, but very few local studies were dedicated for Sabah region. This work aims to fill the gap by presenting the descriptive statistics on the variability of $PM_{10}$ concentration in the urban atmosphere of Sabah. To further examine its diurnal and weekly cycle pattern, its responses towards the variations of CO, $NO_2$, $SO_2$, and ozone were also investigated. The highest mean value of $PM_{10}$ for the whole study period is seen from Tawau ($35.7{\pm}17.8{\mu}g\;m^{-3}$), while the lowest is from Keningau ($31.9{\pm}18.6{\mu}g\;m^{-3}$). The concentrations of $PM_{10}$ in all cities exhibited seasonal variations with the peak values occurred during the south-west monsoons. The $PM_{10}$ data consistently exhibited strong correlations with traffic related gaseous pollutants ($NO_2$, and CO), except for $SO_2$ and $O_3$. The analysis of diurnal cycles of $PM_{10}$ levels indicated that two peaks were associated during the morning and evening rush hours. The bimodal distribution of $PM_{10}$, CO, and $NO_2$ in the front and at the back of ozone peak is a representation of urban air pollution pattern. In the weekly cycle, higher $PM_{10}$, CO, and $NO_2$ concentrations were observed during the weekday when compared to weekend. The characteristics of $NO_2$ concentration rationed to CO and $SO_2$ suggests that mobile sources is the dominant factor for the air pollution in Kota Kinabalu; particularly during weekdays.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.3 no.3
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• pp.149-153
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• 1970

The present study deals with dynamical relationships between variations of common mackerel and horse mackerel catches in the waters adjacent to Korea for the years 1926 to 1969. The materials used here were obtained from Fishery Statistics published by the Bureau of Fisheries and the Fisheries Research and Development Agency of Korea, Secular variations of common mackerel and horse mackerel catches were classified intc five stages from A to E as shown in Fig. 2. As to variations of catch, the two species have alternating cycle trends occurring every ten years. With regard to the long period trend of catch, there is no correlation between annual variations of the species caught. Dynamical relationships between the two species showed a somewhat different pattern of catch as they transferred from one stage to another of the secular variations.

• Asian-Australasian Journal of Animal Sciences
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• v.16 no.1
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• pp.6-10
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• 2003

The present study investigated peripheral plasma immunoreactive inhibin (ir-inhibin) concentrations in relation to the stage of oestrous cycle and progesterone concentrations in cycling Sahiwal cattle (Bos indicus) and Murrah buffaloes (Bubalus bubalis). Blood samples were collected once daily for thirty-two consecutive days from cattle and buffaloes (5 each) during winter months of January and February. Mean (${\pm}$S.E.M.) plasma ir-inhibin concentrations ranged from $0.40{\pm}0.01$ to $0.59{\pm}0.03ng/ml$ in cattle and from $0.29{\pm}0.03$ to $0.52{\pm}0.05ng/ml$ in buffaloes. In cattle, ir-inhibin concentrations increased from $0.47{\pm}0.07ng/ml$ on day -4 (day 0=day of oestrus) to reach a maximum value of $0.59{\pm}0.03ng/ml$ on day -2. Thereafter, ir-inhibin concentrations showed a decline to reach a low of $0.40{\pm}0.01ng/ml$ on day 11 of the oestrous cycle. In buffaloes, ir-inhibin concentrations increased from $0.38{\pm}0.04 ng/ml$ on day -4 to reach a maximum concentration of $0.52{\pm}0.05ng/ml$ on day -2. Ir-inhibin concentrations then declined to reach a low of $0.29{\pm}0.03ng/ml on day 9 of the cycle. In both cattle and buffaloes, ir-inhibin concentrations which were lowest ($0.43{\pm}0.02$ and $0.34{\pm}0.02ng/ml$, respectively) during the mid-luteal phase of the oestrous cycle increased (p<0.05) to $0.52{\pm}0.03$ and $0.44{\pm}0.04ng/ml$, respectively, during the late luteal phase, and then further to the highest value of $0.53{\pm}0.02$ and $0.49{\pm}0.04ng/ml$, respectively, during the perioestrus phase, following which these declined to $0.50{\pm}0.02$ and $0.39{\pm}0.03ng/ml$, respectively, during the early luteal phase. The variations in peripheral plasma ir-inhibin profile in both the species appear to be related to the changes in characteristics of follicular populations during the oestrous cycle. Peripheral plasma ir-inhibin concentrations were negatively correlated with progesterone concentrations in cattle (r=-0.51, p<0.01) and buffaloes (r=-0.30, p<0.01) indicating that the corpus luteum is not a source of peripheral ir-inhibin in these species.