• Korean Journal of Microbiology
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• v.26 no.1
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• pp.44-51
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• 1988

The intracellular free radicals produced at different stages of cell cycle of Saccharomyces cerevisiae ATCC 24858 were investigated by means of electron spin resonance(ESR) spectroscopy. The synchronized cells by repeated starvation and refeeding revealed different ESR spectral pattern compared to that of asynchronized cells. Each spectrum centered at g=2.005, which indicates free radicals. The relative spin concentration was maximat at the end of DNA increase. The variation of the relative spin concentration at each distinct stage of the cell cycle was evaluated in relation to ascorbate concentration, L-galactonolactone oxidase activity, and ascorbate oxidase activity. The highest activities of L-galactonolactone oxidase and ascorbate oxidase were detected just before and at the maximum of relative spin concentration, respectively. And ascorbate concentration fluctuated through each stage of cell cycle with the changes of relative spin concentration, L-galactonolactone oxidase activity, and ascorbate oxidase activity. Thus it is suggested that intracellular free radicals should be related to cell cycle, interacted with ascorbate, and may play an important role in the cell cycle of Saccharomyces cerevisiae.

• The Korean Journal of Malacology
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• v.22 no.2
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• pp.143-150
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• 2006

The gonad index, condition index, reproductive cycle and spawning of the pen shell Atrina (Servatrina) pectinata were investigated using samples from the subtidal zone of Nokdo on the Boryeong coastal waters of Korea. Samples were collected monthly by SCUBA divers for one year from January to December, 2001. A. (Servatrina) pectinata is dioecious and oviparous. The spawning season of this species occurred once a year from June to August, with the main spawning occurring between June and July when the seawater temperature was around $20^{\circ}C$. Ripe oocytes were about 60-65 ${\mu}m$ in diameter. The reproductive cycle of this species could be classified into five successive stages; early active stage (November to March), late active stage (February to May), ripe stage (April to July), partially spawned stage (June to August), and spent/inactive stage (August to October). Monthly changes in the gonad index reached a maximum (4.6) in May (ripe stage), thereafter, the GI values gradually decreased from June to August when spawning occurred continuously. Therefore, monthly changes in the GI values showed a similar pattern to the gonadal phase. The condition index (CI) of the meat part without the posterior adductor muscle reached the maximum in June (ripe and partially spawned stage) and the minimum in September (spent/inactive stage), Accordingly, monthly changes in the condition indice of the meat part without the posterior adductor muscle coincided with the gonadal phases.

• The Korean Journal of Malacology
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• v.24 no.1
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• pp.1-10
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• 2008

Spermatogenesis and the reproductive cycle in male Spisula sachalinensis were investigated by cytological and histological observations. The morphology of the spermatozoon has a primitive type and is similar to those of other bivalves in that it contains a short midpiece with four mitochondria surrounding the centrioles. But spermatozoon of this species has not axial rod and satellite body in the midpiece. The morphologies of the sperm nucleus type and the acrosome shape of this species have a globe-shape type and modified cap-like shape, respectively. The spermatozoon is approximately $40-45{\mu}m$ in length including the sperm nucleus length (about $1.35{\mu}m$), acrosome length (about $1.50{\mu}m$) and tail flagellum. The axoneme of the sperm tail flagellum consists of nine pairs of microtubules at the periphery and a pair at the center. The axoneme of the sperm tail shows a 9+2 structure. The spawning period of these species lasts from June to July, and the main spawning occurs in July when seawater temperatures are greater than $20^{\circ}C$. The male reproductive cycle of this species can be categorized into five successive stages: early active stage (October to January), late active stage (February to April), ripe stage (April to June), partially spawned stage (June and July), and spent/inactive stage (August to September).

• The Korean Journal of Malacology
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• v.24 no.2
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• pp.97-104
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• 2008

The gonad index, reproductive cycle and first sexual maturity of Sinonovacula constricta collected from Simpo, Kimje-gun, Korea were investigated by histological analysis. The gonad index(GI) in both sexes of S. constricta increased from April and reached a maximum in July when the water temperature rapidly increased. And then, the GI values gradually decreased by spawning from August through October. Monthly variations in the GI showed a close relationship with ovarian development. The reproductive cycle in females and males can be classified into five successive stages: early active stage(March to June), late active stage(May to July), ripe stage(July to September), partially spawned stage(August to October), spent/inactive stage(October to March). The percentage of first sexual maturations in female and male clams of 50.1-60.0 mm in shell length was over 50%, and for clams over 70.1 mm in shell length, it was 100%. Because harvesting clams < 50.1 mm in shell length could potentially cause a drastic reduction in recruitment, a measure including a prohibitory fishing size should be taken for adequate improved fisheries resource management.

• Proceedings of the SAREK Conference
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• 2009.06a
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• pp.1484-1490
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• 2009

Since the cooling performance of a $CO_2$ cooling cycle is varied significantly with a variation of refrigerant charge amount and outdoor temperature, the reliability of $CO_2$ system is down. In this study, the performance characteristics of three kinds of $CO_2$ systems were measured and analyzed by varying refrigerant charge amount and outdoor temperature so as to study the characteristics of variation with cycle option. The applied system options are the single-stage compression(1C-1E) system, two-stage compression with 1-EEV(2C-1E) system, and two-stage compression with 2-EEV(2C-2E) system. The performances of two-stage compression with 2-EEV system were less sensitive than those of other systems and the system operated safely and steadily for wide charge amount. The performance of the two-stage compression with 1-EEV(2C-1E) system was the most sensitive to the charge amount, and that of the single-stage compression(1C-1E) system varied a lot with outdoor temperature.

• Reproductive and Developmental Biology
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• v.28 no.1
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• pp.53-57
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• 2004

The study was carried out to investigate the effects of morphology, reproductive cycle, incubation time and activation of oocytes on in vitro maturation of cat oocytes and development of IVM/IVF embryos. The results were summarized as follows: 1. When recovered from ovaries collected at different stages of the reproductive cycle (inactive, follicular and luteal stage), the developmental rates of oocytes to GV and MI stage were 72.5% and 27.5%, 57.5% and 7.5%, 62.5% and 17.5%, respectively. 2. The developmental rates of oocytes with cumulus cells to GV and MI stage in different conditions of incubation (5% $CO_2$ , 95% $O_2$ and 10% $CO_2$, 90% $O_2$) were 70.0% and 27.5%, 52.5% and 20.0%, 55.0% and 12.5%, respectively. 3. The developmental rates to GV and MI oocytes when cultured at different time of incubation (17∼20, 21∼24, 25∼28 and 29∼32 h) were 67.5% and 20.0%, 67.5% and 30.0%, 62.5% and 22.5%, 65.0% and 15.0%, respectively. 4. The fertilization and cleavage rates of freshly collected oocytes with and without cumulus cells were 72.5% and 25.0%, 37.5% and 7.5%, respectively. The rates were greater in oocytes with cumulus cells than those without cumulus cells. 5. The fertilization and cleavage rates of oocytes recovered from ovaries collected at different stages of the reproductive cycle (inactive, follicular and luteal stage) were 75.0% and 25.0%, 40.0% and 7.5%, 50.0% and 15.0%, respectively.

• Journal of the Korean Solar Energy Society
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• v.31 no.1
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• pp.23-30
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• 2011

International cooperation to reduce greenhouse gas emissions is expected to provide a big crisis and a great opportunity at the same time for our industry that heavily consumes energy. To cope actively with the international environmental regulation, such as the Framework Convention on Climate Change, quantitative measurement of the volume of greenhouse gases emitted by various industries and quantitative prediction of the greenhouse gas emissions of the future are becoming more important than anything else at the national level. This study aims to propose the calculation process of carbon dioxide($CO_2$) emission for building in life cycle. This paper describes and compares 9 different tool for environmental load estimation with LCA. This study proposed the calculation process for quantitatively predicting and assessing $CO_2$ emissions during the life cycle of buildings based on the life cycle assessment(LCA). The life cycle steps of buildings were divided into the design/supervision, new construction, repair, renovation, use of operating energy in buildings, maintenance, and reconstruction stage in the life cycle inventory analysis and the method of assessing the environmental load in each stage was proposed.

• Development and Reproduction
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• v.17 no.2
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• pp.87-97
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• 2013

The seminiferous epithelium cycle and developmental stages of spermatids in Clethrionomys rufocanus were observed under a light microscope. The seminiferous epithelium cycle was divided into 8 stages. Type Ad spermatogonia appeared through all stages. Type Ap, In, and B spermatogonia appeared in stages I, II, III, and IV. In the first meiosis prophase, the leptotene spermatocytes appeared from stage V, the zygotene spermatocytes in stages I, VI, VII, VIII, the pachytene spermatocytes from stages II to VI, the diplotene spermatocytes in stage VII. The meiotic figures and interkinesis spermatocytes were observed in stage VIII. Developing spermatids were subdivided into 10 steps, based on the morphological characteristics such as the acrosome formation changes in spermatozoa, nucleus, cytoplasm, and spermiation changes. The C. rufocanus spermatocytogenesis and spermiogenesis results displayed similar results with Apodemus agrarius coreae and A. speciosus peninsulae. Considering all the results, the spermatogenesis may be useful information to analyze the differentiation of spermatogenic cells and the breeding season.

• Journal of the Korean Society of Clothing and Textiles
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• v.26 no.2
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• pp.280-291
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• 2002

This study was to apply FLC(Fashion Life Cycle) concept with extended PLC(Product Life Cycle) theory of marketing for a basis. This article was particularly analyzed relations between demographic variables and fashion lifestyle toward consumer's behavior at decline stage of FLC empirical study was to target women's formal dress. Data were collected from the adult females residing in Youngnam district. Sampling were peformed pretest and main survey. Total 386pcs of answers were used for final analysis. The results of analysis were as follows. First, Hypothesis 1 & 4 were showed meaningful differences between fashion lifestyle patterns and consumer's behavior at decline stage of FLC according to demographic characteristics. Second, Hypothesis 2 also was adopted meaningful differences of consumer's hoarding behavior at decline stage of FLC in accordance with fashion lifestyle patterns. Third, Hypothesis 3 of fashion lifestyle patterns which has related consumer's recycling behavior at decline stage of FLC was rejected. In conclusion, This article discusses implication of fashion marketing strategies and summaries..

• Journal of Aquaculture
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• v.16 no.3
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• pp.179-186
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• 2003

Reproductive cycle, gonadal development and the spawning period of the Korean anchovy Coilia nasus were investigated by histologhical observations. Samples were collected at the coastal area of Geumgang dyke which is connected to Gunsan and Janghang, Korea, from February 2002 to January 2003. C. nasus is dioecious; the ovary consists of a pair of saccular structure with many ovarian lobules, and the testis consists of a pair of lobular structure with many testicular lobules and connected to the posterior seminal vesicle. Monthly changes in the gonadosomatic index (GSI) began to increase in April when seawater temperature increased and reached the maximum in June when the ovary was getting mature, the summer season of longer day length with higher water temperature. The reproductive cycle can be classified into five successive stage in females: early growing stage (February to March), late growing stage (March to April), mature stage (May to June), ripe and spent stage (June to July), and recovery and resting stage (July to January): in males, the cycle can be divided into four successive stages; growing stage (February to April), mature stage (May to July), ripe and spent (June to July), and recovery and resting stages (July to January). According to the frequency distributions of egg diameters in the spawning season. C. nasus is presumed to be summer spawning species and polycyclic species to spawn 2 times or more during the spawning season.