• Korean Journal of Fisheries and Aquatic Sciences
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• v.20 no.6
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• pp.501-508
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• 1987

Gonadal development, the annual reproductive cycle and the first sexual maturity of hen clam, Mactra chinensis were studied histologically. Sexuality of the species was dioecious. The gonads were irregularly arranged from the subregion of mid-intestinal 91an4 in visceral cavity to the reticular connective tissue of the foot. The ripe eggs were about $50-60\;{\mu}m$ in diameter, and they were surrounded by gelatinous membrane. The spawning period was from May to September when the water temperature ranged $18.5-27.0^{\circ}C$, with the peak in June and July. The annual reproductive cycle of Mactra chinensis could be classified into five successive stages; multiplicative, growing, mature, spent, and degenerative and resting. The monthly changes of the fatness coefficient closely correlated with the annual reproductive cycle. Percentages of the first sexual maturity of female and male clams were over $50\%$ among those individuals ranging from 3.5 to 3.9cm, and $100\%$ in those over 5.0cm in shell length.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.13 no.2
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• pp.57-64
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• 1980

Seed tunicates of Halocynthia roretzi (v. DRASCHE) which were artificially settled in Chungmu area were transplanted to Seonyudo and Eochungdo to know the feasibility of the tunicate culturing in the western coast of Korea. From April 1978 to March 1979, the growth of the transplanted tunicate in the two area was compared and analyzed in reference to the ecological factors. At the time when the seeds were transplanted, the mean body height of Halocynthia roretzi(V. DRASCHE) was 1.84 mm, body breadth 1.42 mm, and the body weight 15.0 mg. After 333 days the mean body height was 10.77 mm, body breadth 6.75 mm, and body weight 201 mg in Seonyudo area. In Eochungdo area the mean body height was 13.5 mm, body breadth 11.51 mu and body weight 880 mg. According to above results, it is possible to culture the seeds in Eochungdo area. Salinity $(29.2-32.0\%_{\circ})$ was favorable, water temperature $(6.8-26.8^{\circ}C)$ was not a critical factor, but the growth of the tunicate was affected by the high temperature$(over\;25.0^{\circ}C)$ in July. Transparency lower than 1.0 m seriously affects the growth of the tunicate, and it was one of the important factors inhibiting the growth of the tunicate. Seonyudo area was found out to be inadequate for the culture of the sea spuirt Halocynthie roretzi because of the retarded growth in body breadth and weight while showing extended growth in body length then leading to higher mortality owing to large amount of silting and fouling of the colonial tunicate, Didemnum (didemnum) moseleyi.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.16 no.3
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• pp.291-297
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• 1983

This paper describes the variations of the distribution of dissolved oxygen in the Japan Sea in summer during 1974-1977. In the Tsushima Current region of the Japan Sea the salinity maxima appears frequently in summer and the dissolved oxygen at the salinity maximum is less than that in the Japan Sea Proper Water. The Japan Sea is divided into three parts with respect to the type of vertical profiles of dissolved oxygen: The southern region of about $35^{\circ}N$ which has low dissolved oxygen similar to those in the Kuroshio region, the Japan Sea Proper Water region, and the area between about $36^{\circ}N$ and $40^{\circ}N$ which has high dissolved oxygen. The ranges of the dissolved oxygen and thermosteric anomaly(${\delta}_T$) at the salinity maximum are roughly between 4.9 and 6.5 m/l and between 210 and 240 cl/t respectively. The most frequent ranges of those values are between 5.5 and 5.7 ml/l and between 230 and 240 cl/t. The northern boundary of the Tsushima Current can be known by the characteristics of the distribuion of dissolved oxygen.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.13 no.2
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• pp.81-87
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• 1980

As a part of the experiments on-the utilization of krill, Euphausia superba, general composition, pH, volatile basic nitrogen, amino-N, and free individual amino acid were analyzed for invertigating the processing condition and quality factors in the salted and fermented krill. The results ascertained were shown that the propel concentration of salt was $ 22-27\%$ and addition of $3.9-5.9\%$ of ethyl alchool contributed to improve flavor and appearance of the salted and fermented krill. The amino-N of the salted and fermented krill showed a rapid increase as much as 3.2 times that of fresh krill. Free amino acid composition, aspartic acid, leucine, tyrosine, isoleucine and glutamic acid which were poor in fresh frozen krill showed a fast increasing tendency, whereas glycine, proline, lysine, arginine and alanine which were abundant in fresh frozen krill showed a slow increasing tendency during the process of salted fermenting.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.14 no.4
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• pp.221-226
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• 1981

The seedlings of the scallop, Patinopecten yessoensis, which were collected in April 1980, April 1981 and May 1981, and the grown-up scallops collected in the sea bottom in November 1979, were reared by hanging method up to the July 1981. The growth of the seedlings collected in April 1980 was greatly affected by the time of the seedling collection, manipulation of the net cage, density in the net cage and the annual water temperature fluctuation. The scallops reared from the spat collected in April 1980 reached the sizes of 0.33 mm, 1.23 mm, 29.34 mm and 59.59 mm in shell length in 40,75, 285 and 450 days respectively. Since then, growth rate was determined as follows based on the age estimated by the year rings on the shell:84.96mm in 19 months, 99.3mm in 31, 112.3mm in 37 and 113.64mm in 43 months. The meat and the adductor muscle weight increased with the shell length. The meat weight roached about 15g when the shell length was 60-70mm and about 94.13 g when 130-140mm, and the adductor muscle weight reached about 4.89 g when the shell length was 60-70 mm and about 39.59g when 120-130 mm. But the growths of the meat and the adductor muscle weight were in stagnancy after scallops reached 125 mm in shell length.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.16 no.3
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• pp.190-196
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• 1983

This experiment was carried out to compare the change of muscle protein compositions, amino acid compositions of muscle protein, and free amino acid compositions by age of the Israeli strain of common carp, Cyprinus carpio nudus. Protein compositions of the muscle were: sarcoplasmic protein $25.8-27.2\%$, myofibrillar protein $62.3-56.2\%$, residual intracellular protein $9.6-13.2\%$ and stroma $2.3-2.9\%$. In between 1 year and 3 years, there were differences as follows; myofibrillar protein in 1 year was much than 3 years, and other proteins in 3 years were much than 1 year. By SDS-polyacrylamide gel electrophoresis, sarcoplasmic protein of the samples in 1 year an 3 years were composed of 11 subunits and 10 subunits, respectively. And appeared 210,000 dalton component in 1 year but did not appeared in 3 years. Myofibrillar protein was composed of 23 subunits in both 1 year and 3 years but the differences of subunits by age were not observed. No differences were observed by age in the composition of myofibrillar protein and residual intracellular protein. Amino acid composition of muscle protein in both 1 year and 3 years were no differences to each other, but the contents of glutamic acid, aspartic acid, lysine were higher than other amino acids. The amount of total free amino acid in 1 year was much than in 3 years.

• Journal of the korean academy of Pediatric Dentistry
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• v.29 no.2
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• pp.180-188
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• 2002

Newly developed curing units(plasma arc curing units) operate at relatively high intensity and are claimed to result in optimum properties of composite resin in a short curing time. The purpose of this study was to evaluate the microhardness and microleakage at the resin-tooth interface of two types of composite resins polymerized with visible light and plasma arc curing units. The results from the present study can be summarized as follows 1. Microhardness in each depth was shown to be higher in group AHL than AP3 & AP6. Group ZHL was lower than AP6 at surface(p<0.05) and had no statistically significant difference at 1mm and 2mm(p>0.05). In other depths, group ZHL was higher than ZP3 and ZP6(p<0.05). 2. The incremental reduction in microhardness with depth was shown to be in all group except in surface-1mm of group AHL and $1{\sim}2mm$ of group ZHL(p<0.05). 3. Degree of microleakage in all oops were shown to be higher in gingival margin than occlusal margin but no statistically significant difference(p>0.05). 4. Differences between curing methods in microleakage were shown to be no statistically significant difference(p>0.05). 5. Differences between composite resins in microleakage were shown to be no statistically significant differ once(p>0.05).

• Korean Journal of Occupational Health Nursing
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• v.4
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• pp.48-57
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• 1995

The purpose of this study was to assess the performance of the role and function of some industrial nurses and to characterize the factors affecting the performance of their activities. Thus the results could be used to suggest the direction in the performance of industrials nurses' activities effectively. During a period from January 10 to March 31, 1994, the data were collected from 87 industrial nurses, who were working as health managers in the plants, in Ulsan city and the vicinity in Kyungnam province, using a structured questionnaire. The results were as follows : 1. The general characteristics of industrial nurses in this study were 82.8% being 30 years old or less, 60.9%, being not married, and 93.1% having eduction levels above junior college. 2. With respect to general work conditions, 94.3% were working in a separate room provided for health care division, 40.2% working under the safety and health department, and 98.9% working as common-level staffs. And 60.9% were working less than 44 hours a week, 70.1% had work experiences less than 5 years, and 50.6% had annual incomes ranging 10 to 14 million wons. 3. As work conditions related to health care activities, 49.4% performed the activities not related to health care as always or occasionally, and 87.4% answered that occupational physicians were appointed in their plant and among them, however, only 6.9% worked on full-time basis and 52.8% perform little activities as occupational physicians. For a decision related to health care activity, 69.0% discussed the problems with the supervisors, and 19.5% made decisions by themselves. 4. As for attitude and perception to their activities as health managers, 66.7% moderately recognized the importance of health manager in the workplace, with 63.2% being satisfied their wages and treatment from the company, 57.5% being satisfied with their job positions and 51.7% having positive attitudes as being health managers. 5. The degree of performance at least in one of health related activities were very high in activities such as general medical care(100%), general health examination(98.0%) and specific health examination(100%), and relatively high in health education(72%), new employee health examination(60.9%), document handling(79.3%) and activity for work environment(70.1%). However, the performance rate was very low in preparing protective equipment (20.8%). 6. The levels of activities related to health care were significantly high when making decisions by themselves, when occupational physicians not being full-time, and when satisfying their job positions, and, on the other hand, significantly decreased as work hours increased. 7. In addition to some kinds of periodic education asked by all of the nurses, 89.7% wanted a specialized licensing system for industrial nurse, and 97.4% wanted to apply for the license test. As a conclusion, it is suggested that industrial nurses should be given more authority and placed in more self-controlled system to perform health care and other activities more efficiently, and the role and function of the occupational physician should be clearly distinguished from that of the industrial nurse as a health manager to avoid an unnecessary overlapping.

• Journal of Ginseng Research
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• v.28 no.1
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• pp.39-44
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• 2004

The present study is to determine whether the Red-ginseng extract has a proliferative or cytotoxic effect on the human neuronal stem cells(hNSCs). The hNSCs were grown and incubated with different doses of Red-ginseng extract. We tested the proliferative or cytotoxic effects by MTT and FACS analysis. Cell viability cell cycle analysis, DNA fragmentation, and bax or PARP expressions were evaluated. The hNSCs showed a proliferafe trend with its peak concentration at 0.3 $\mu\textrm{g}$/$m\ell$. Beyond this point, higher doses decreased viabilities and showed a cytotoxic effect at 10 $\mu\textrm{g}$/$m\ell$. There was a tendency of increased S and G2/M phases during cell proliferation. In a cytotoxic condition, decreased S phase and increased G0/G1 phases were noted, suggesting cell cycle arrest. The cytotoxic effect was associated with increase DNA fragmentation in a dose-dependent manner, However PARP cleavage or bax expression was not detected. Our results suggest that Red-ginseng extract has dual effects, the cell proliferative or cytotoxic effect, on hNSCs in vitro with dose-dependent manner.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.26 no.4
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• pp.321-329
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• 1993

The present study was conducted to elucidate the body modulating function of fermented seafood products. Angiotensin converting enzyme (ACE) acts in blood pressure regulation, converting angiotensin I to the potent vasoconstrictor angiotensin II and inactivating the vasodilator bradykinin to raise blood pressure. Salted and fermented anchovy which is one of the traditional fermented seafood in Korea was tested for inhibitory activity against ACE. ACE inhibitory activity of salted anchovy during the period of fermentation was increased with the elapse of fermentation days until fermentation of 60 days, but thereafter decreased inversely. When the fermented product was extracted with $50\%$ ethanol, the ACE inhibitory activity was the highest. And the ACE inhibitory activity was proportion to the content of $50\%$ ethanol soluble peptide-nitrogen of the fermented product. From the profiles of gel permeation chromatography on a Bio-Gel P-2 of $50\%$ ethanol soluble fraction obtained from salted and fermented anchovy fermented for 60 days at an ambient temperature, the higher activity fractions were C'($IC_{50}=97{\mu}g\;protein/ml$) and D'($IC_{50}=65{\mu}g\;protein/ml$). Amino acid analysis showed that the large quantify of threonine, glutamic acid, lysine for C' and serine, proline for D', respectively.