• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.34 no.7
• /
• pp.805-811
• /
• 2010

When we design a product, we spend a considerable amount of time in designing fasteners and their mating parts. Fasteners have special features because of which they are widely used and well standardized. Although we use some equations to design the fasteners, we should select these fasteners from the standardized table. In order to design them quickly using the CAD system, we proceeded as follows. First, we prepared some standardized shapes of fasteners to design them automatically. Next, we built a database of some fasteners such as a tension bolt, lock wire, thread, pin, and snap ring. Then, we used the design equations to quickly and precisely calculate the various parameters. Finally, we used a configuration design method to generate the shapes automatically using the results of the calculation and the values retrieved from the database. We applied this approach to the design of a propulsion structure, and demonstrated that this approach worked well and saved considerable time.

• Korean Journal of Animal Reproduction
• /
• v.7 no.1
• /
• pp.19-23
• /
• 1983

Present studies were conducted to investigate the developmental stage and the location of embryos in the reproductive tract at various times after ovulation, the morphologically normal after thawing of embryos preserved in liquid nitrogen, and the survival after transferring frozen-thawed embryos. The results obtained were as follows: 1. Embryo stage and location in the reproductive tract after hCG administration. For the investigation of embryo stage and location in the reproductive tract after ovulation, rabbits were laparotomized at 24, 40, 48, 72 and 120 hrs post hCG injection, simultaneously with mating. the oviducts and uteri were flushed out with PBS medium containing 50% rabbit serum, respectively. 1) Most of embryos was remained in the oviduct within 48 hrs, with the lapse of time, embryos were started to move to uterus and shifted in uterus at 72 hrs after hCG injection. 2) The representatives of embryos stage collected at 24, 40, 48, 72 and 120 hrs were 1-cell(60.4%), 8-cell to early morula (52.3, 39.3%), late blastocyst (95.5%) stages, respectively. 2. Morphological normality and survival of the frozen-thawed embryos. For the evalution of the quality and viability on the frozen-thawed embryos, immediately after thawing, embryos were assessed by morphologically normal under a dissecting microscope, and a further test of frozen-thawed embryos was made by transferring the morphologically normal embryos to the uteri of recipient rabbit induced pseudopregnancy by the injection of hCG at the time of hCG injection in donor rabbits. 1) The propotions of embryos which a, pp.ared morphologically normal was higher when 8-cell (85.7%) and morula(90.5%) were used for freezing than when 4-cell (66.7%) and blastocyst (75.8%) were used. 2) Preganacies were observed at Day 15 after transfer of frozen-thawed 8-cell (7/13), morula (19/42) and blastocyst (3/19) but not after transfer of embryos at 4-cell stage.

• Korean Journal of Veterinary Research
• /
• v.44 no.2
• /
• pp.303-310
• /
• 2004

To establish a prediction table of parturition day real-time B-mode ultrasonographic examinations were performed in 12 pregnant Shih-tzu bitches. Measurement of inner chorionic cavity diameter and fetal head diameter was performed from 15 days of gestation to parturition. These were converted retrospectively based on the day of parturition (Day 0). The data of inner chorionic cavity diameter obtained from Day -44 to Day -25 and fetal head diameter obtained from Day -25 to Day -1 were used to compile a prediction table of parturition day. The 22 pregnant Shih-tzu with unknown mating time were examined to assess an accuracy of the table established in this study. And these results were applied to the prediction of parturition day and compared to actual parturition day. Parturition day prediction based on the inner chorionic cavity diameter and fetal head diameter was 100% accurate within ${\pm}2$ days. In addition, the accuracy for parturition day within 0, ${\pm}1$, and ${\pm}2$ days interval using the prediction table of parturition day were 68, 82, and 100%, respectively. Therefore, the prediction table of parturition day seems to be a useful tool for the prediction of parturition day in practice.

• Applied Microscopy
• /
• v.22 no.2
• /
• pp.97-117
• /
• 1992

In order to study process of spermiogenesis of the Korean greater horseshoe bat, Rhinolophus ferrumequinum korai, the cycle of seminiferous epithelium was examined by the light and electron microscope and the following results were obtained based on the epithelial cell differentiation. 1. Spermiogenesis occurred from early July to mid-Octber, and spermatogenic activity was vigorous from mid-August to late September. Spermatocytes including spermatogonia were found to be degenerated in only July. It is deduced that the degeneration serves as the mechanism to regulate effective use of energy to prepare for mating and hibernating periods, and regulation of breeding cycle. 2. Spermiogenesis of the Korean greater horseshoe bat was divided according to differentiation of the cell structure, into Golgi, cap, acrosome, maturation and spermiation phases; Golgi, cap and spermiation phases were further divided into two steps of early and late phase respectively, and acrosome phase into three steps of early, mid and late phases, and maturation phase has only one step. Hence, the spermiogenesis consists of ten phases. The first research was done in this article on the changes of chromatin with nucleus, the time of appearance and disappearance of chromatin granules, in case of Korean greater horseshoe bat (Rhinolophus ferrumequinum korai). Chromatin granule began to be condensed in late Golgi and the condensation proceeded to form an irregular mass of a electron-dense chromatin in a form of circular cylinder in the center of nucleus at the phase of maturation. Finally, the chromatin condensation proceeded and perfect nucleus of sperm with homogeneous density was formed when the sperm was separated from Sertoli cell. Therefore, appearance and disappearance of chromatin granules occurred in the period of time between late Golgi and maturation phase, The tail of sperm began to develop in early cap phase, Numerous lipid droplets were obseved in the cytoplasm of spermatids during the maturation phase, which seemed to be used as energy source necessary to make mature sperm during spermiogenesis.

• Korean Journal of Environment and Ecology
• /
• v.32 no.2
• /
• pp.244-251
• /
• 2018

The present study aimed to identify the influence of climate change on mating songs of Cicadidae in a phenological perspective. The research sites were located in the central part of the Korean peninsula in which phenological observations by the Meteorological Office are made. The material provided by the Meteorological Office was used for long term phenological analysis. The findings demonstrated, First, the phenological monitoring of cicada is an effective index to detect ecological changes due to climate change, thus indicating the importance of long term phenological investigations for future studies. Second, the analysis on the phenological changes of H. fuscata presented a trend in which the first songs were made at increasingly earlier and later dates, respectively. The phenological data on H. fuscata and average temperatures exhibited a significant negative correlation between the initial mating song period and the average temperatures of June. Furthermore, there was also a significant negative correlation for precipitation in October with the end time and total duration of H. fuscata song. Third, in the regression analysis of the start of H. fuscata song and meteorological factors in Seoul, increasing average air temperature in spring (March to June), which includes June, was associated with an earlier start time of H. fuscata song, with calling starting approximately 3.0-4.5 days earlier per $1^{\circ}C$ increase. Fourth, in the regression analysis of the end of H. fuscata song and meteorological factors in Seoul, increased mean precipitation in October was associated with an early end time and an overall reduction in the length of the song period. The end time of song decreased by approximately 0.78 days per 1mm increase in precipitation, and the total length of the song period decreased by 0.8 days/1mm. This research is important, as it is the initial research to identify the phenological changes in H. fuscata due to climate change.

• Journal of Embryo Transfer
• /
• v.28 no.1
• /
• pp.25-30
• /
• 2013

The aim of this study was to estimate of ovulation time and parturition day at the same time as breeding in small dog by vaginal cytology and to confirm the accuracy by comparing the expected parturition day and the real one. Characteristic features of vaginal cytology during the estrous cycle were the high proportion of large intermediate cell, superficial cell, anuclear cell and erythrocyte in proestrus, superficial cell and anuclear cell in estrus, parabasal cell, small intermediate cell, large intermediate cell and leukocyte in diestrus, parabasal cell and small intermediate in anestrus, respectively. When day 0 was the parturition day, the period of pregnancy is 67.45(64~75) days when the cornification index (CI) is over 90%. Also, on the basis of ovulation day, 63.65(59~66) days was confirmed, and 57.0(52~60) days was confirmed based on the first day of diestrus. There are the gap of 4 days between the day being over 90% in CI and ovulation day. On the basis of this, when expecting parturition day based on the day being over 90% in CI by vaginal cytology, 18.1% was produced in the same of the expected parturition day and the real one, 30.3% and 33.3% were produced in the gap of one day and two days, respectively so, the accuracy within two days was 81.7%. In addition, based on the first day of diestrus, it also was identified to 81.7% as the difference between the expected parturition day and the real one within 2 days. It demonstrated there are any difference between any expected parturition day by vaginal cytology. Thus on the basis of the day of being over 90% CI, it is fully thought to using clinically due to the possibility of prediction the parturition day at the same time as the determination of the proper time of the optimal mating time.

• Asian-Australasian Journal of Animal Sciences
• /
• v.18 no.2
• /
• pp.249-254
• /
• 2005

The objective of this study was to investigate effects of dietary level of CLA and the duration of feeding CLAcontaining diets on reproductive performance in sows and piglet growth rate. Tallow (3% in gestation diet and 5% in lactation diet, respectively) was incorporated as a fat source in control diet, and each 50% (dietary CLA level of 0.75% in gestation diet, and 1.50% in lactation diet, respectively) or 100% (dietary CLA level of 1.50% in gestation diet, and 2.50% in lactation diet, respectively) of tallow was replaced by a commercial CLA preparation containing 50% CLA isomers. Diets containing CLA were fed either from d 15 premating to weaning or d 74 post-mating to weaning. The level of dietary CLA and feeding duration did not affect litter size. High dietary level of CLA, however, decreased piglet weights at birth (p<0.01) and tended to decrease backfat thickness of sows at weaning. Longterm feeding of CLA-containing diets decreased piglet weights at weaning (p<0.05) and backfat thickness of sows at weaning (p<0.05). CLA supplemented in sow diet was transferred to fetus and piglets during pregnancy and nursing period, respectively. CLA contents of femoral muscle of piglets were 2.08 to 2.57 mg per g of fat at birth, and 2.36 to 4.47 mg at 10 days of age in CLA groups, while CLA was not detected in the control group. In conclusion, dietary supplementation of CLA tended to lower backfat thickness of sow and piglets' weight at birth or weaning, but did not affect total litter size. Dietary CLA was transferred efficiently during prenatal and postnatal periods of time through the placenta and milk, respectively.

• Asian-Australasian Journal of Animal Sciences
• /
• v.24 no.7
• /
• pp.919-928
• /
• 2011

The pig exhibits true epitheliochorial placentation, where the fetal membrane maintains attachment throughout pregnancy but does not invade into the maternal uterine endometrium. Accordingly, the expression and function of cell adhesion molecules are very important for embryo implantation and the establishment of pregnancy. In our recent microarray analysis, we found that activated leukocyte cell adhesion molecule (ALCAM) was expressed in the uterine endometrium during pregnancy in pigs. To better understand the roles of ALCAM in the establishment and maintenance of pregnancy, we examined ALCAM expression in the uterine endometrium during the estrous cycle and pregnancy in pigs. Real-time RT-PCR analysis showed that ALCAM was differentially expressed in the uterine endometrium during the estrous cycle and pregnancy, with the highest levels on D12 of pregnancy. ALCAM mRNA was localized to the luminal and glandular epithelial cells and to the trophectoderm of conceptuses during early pregnancy. The steroid hormones estrogen and progesterone had no effect on ALCAM expression in an endometrial explant culture study. Further, we found that ALCAM expression in the uterine endometrium from gilts with somatic cell nuclear transfer-derived embryos was not different from that in gilts with embryos from natural mating. ALCAM was expressed in a pregnancy stage- and cell type-specific manner in the uterine endometrium and conceptuses during pregnancy. These findings suggest that ALCAM may play a role in the establishment of pregnancy. Further analysis of ALCAM will provide insight into the implantation process and establishment of pregnancy in pigs.

• Journal of Mushroom
• /
• v.2 no.4
• /
• pp.225-227
• /
• 2004

Hukbaek oyster mushroom were bred and cultivated one after mating spores from Aenutari 1-ho irradiated to X-ray and Byungnutari 1-ho. The major charateristics of the mushroom are showing that pileus is black-brown and stems are pure-white and straight. The optimum temperature for the mycelial growth was around $25{\sim}30^{\circ}C$ and that for the pinheading and growth of fruitbody was around $14{\sim}16^{\circ}C$. Around 20 days at $20^{\circ}C$ were required for incubation time and the yield was shown high by 142.8g/bottle. When the cultivating temperature is over $17^{\circ}C$ the color of pileus becomes gray-brown.

• Toxicological Research
• /
• v.17
• /
• pp.135-138
• /
• 2001

Female Wistar rats were randomly divided into 5 groups: Control, received distilled water; Low lead, received 0.5 g/ιlead (as acetate) in drinking water; High lead, received 2.0 g/ιlead; Low lead + Minerals, received 0.5 g/ιlead in drinking water and received minerals (Ca$^{2+}$, 25 mg/kg/day; Fe$^{3+}$, 0.47 mg/ kg/day; Zn$^{2+}$, 0.33 mg/kg/day; Se, 0.83 $\mu\textrm{g}$/kg/day) by gavage; High lead + Minerals, received 2.0 g/ιlead and received the same minerals. Animals exposure to lead was from 10 days before mating till postnatal day 21; and the minerals was administered from the first day of pregnancy and during lactation. No statistical difference was found either in body weights or in blood lead levels between the pups received minerals and those only exposed to lead at the same dose. The developmental and behavioral teratological effects of lead on pups, such as time-lag of eye opening, pinna detachment, fur developing, incisor eruption, ear unfolding, and surface righting were observed in this study; and the minerals decreased the toxicity of lead either in low or in high lead exposure pups. The numbers of step-down were significantly increased in lead exposed animals, and the effect of intervention by the minerals was appeared only in the pups exposed to low lead. The ChAT activity and levels of glutamate and aspartate in hippocampus decreased in treated animals compared to control animals, no effect of intervention by the minerals was found. The results of this study indicate that the applied multi-minerals can alter the outcome of develop-mental lead poisoning in rats.s.s.s.