• Proceedings of the Korean Society of Fisheries Technology Conference
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• 2001.10a
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• pp.339-340
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• 2001

이매패류의 의투막은 외부의 자극에 생물학적으로 처음 반응하는 기관계로서 자극을 외투강 기관계와 내장 기관계에 전달함과 동시에 외투강내의 모든 기관계를 이차적으로 보호하는 구조이다. 이매패류의 외투막은 자극수용, 외투강내 물질수송 및 패각형성 등 중요 기능을 가지고 있다 (Neff, 1972b; Wilbur, 1972, 1985; Machin,1977; Crrenshaw, 1980). 이매패류 외투막의 구조에 관해서는 Lyonsiidae의 일부 종(Prezant, 1981)과 Crassostrea (Morrison, 1993)등에 관한 일부 보고가 있을 뿐이다. (중략)

• Proceedings of the Korean Society of Fisheries Technology Conference
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• 2001.10a
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• pp.337-338
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• 2001

이매패류는 내장 기관계와 외투강 기관계에 다양한 분비선을 가지는데, 이들 분비선은 대부분 단세포선의 형태이다. 선세포의 종류는 기관에 따라 다르며, 동일한 기관일지라도 생물종에 따라 현미경적 구조와 기능이 다양하게 보고되고 있다. 일반적으로 외투강 기관계 가운데 외투막 상피층에 존재하는 선세포들은 주로 외투강의 정화 및 패각형성에 관여한다. 아가미에 존재하는 선세포들은 발달된 섬모들과 함께 먹이 포획 기능을 하고, 발의 상피층을 구성하는 선세포들은 점액을 분비하여 내부 근육층을 보호하고 아울러 저질 잠입에 유리한조건을 제시하게 된다. (중략)

• Journal of Technology Innovation
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• v.24 no.4
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• pp.127-158
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• 2016

Multinational corporations' overseas R&D activities bring host countries positive effects such as knowledge spillover, technology transfer, job creation and etc. For this reason, many countries have made efforts to attract foreign firms' R&D investment in their national territories. Korean government have also implemented some policy measures to expedite foreign firms operating in Korea to increase R&D activities. However, the firms' R&D investment in Korea has still been unsatisfactory, and only few studies have examined this issue. Therefore, this study attempts to explain the R&D investment of foreign firms operating in Kore, from the perspective Dunning's eclectic paradigm. Utilizing linear regression and Tobit model, this study analyzes the influence of OLI advantages on R&D intensity of foreign firms in Korea. The result shows that locational advantages of Korea (such as revealed technological advantage) had positive influences on foreign firms' R&D intensity. However, the influence of other OLI advantages were different by foreign firms' nationalities. For instance, internalization advantages had influences on R&D intensity, but the directions were different between Japanese and other nationalities. Based on the results, we provided some discussion and attempted to draw implications for Korean government's FDI and R&D policy.

• The Korean Journal of Malacology
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• v.7 no.1
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• pp.66-75
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• 1991

금강수위에 서식사는 패류의 중금속함량을 알아 보기 위하여 1001년 4월부터 동년 10월사이에 우기를 피하여 금강유역에서 8개 지소를 임으 선택하여 채집한 8종의 부족류 중 비교적 각 지역에서 공통적으로 채집될 수 있었던 말조개와 채첩을 각각 10개체씩 선택하여 패를 아가미, 외투막, 폐각근, 족근 및 내장기관등 각 부위별롸 나누어 Cd, Cu, Pu, Zn의 함량을 원가흡광법으로 분석하여 다음과 같은 결론을 얻었다.1. 각 부위별 중금속 함량을 전체적으로 본 평균값은 Zn을 제외하고는 전체 패류의 내장부위가 모두 다른 어느 부위보다도 매우 높은 함량을 나타냈으며, 그 다음은 지역에 따라 다소의 차이는 있언ㅆ지만 대부분 외투막과 아가미, 족근, 폐각근의 순으로 나타났다.2. 각 패류별 중금속 함량은 역시 Zn만을 제외하고는 상류로부터 하류로 내려감에 따라 중금속 함량이 높아지는 경향을 보였다.3. 여러 금속 중 Zn만이 각 부위별에서 내장부위보다 아가미, 외투막에서 비교적 높은 값을 볼 수 있었으며, 일반적으로 다른 중금속은 하류보다 상류가 그 함량이 적은 경향을 보였으나, Zn만은 상류족에서 비교적 높은 함량을 보였고, 지역에 따라 그 함량이 다른 경향을 나타내었다. Zn 다음의 중금속함량은 Cu, Pb, Cd의 순으로 그 농도를 나타내었다.

• The Korean Journal of Malacology
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• v.24 no.1
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• pp.41-50
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• 2008

The histochemical characteristics and ultrastructure of the mantle in the spiny top shell, Batillus cornutus were described using light and electron microscopy. The simple epidermal layer wrapped on the top and bottom of the centrally located connective tissue. And then the epidermal layer were divided into the outer epidermal layer near a shell and the inner epidermal layer closed to the visceral mass. The connective tissue layer was composed of the collagen fiber muscularfiber bundle and hemolymph sinus. Mucous cells in the apical mantle contained acid and neutral mucopolysaccaride, and acidic carboxylated mucopolysaccaride in the mid and marginal mantle. The mantle thickness, epidermal layer thickness and hemolymph sinus area displayed a trend of reduction from the marginal zone to the apical zone. From TEM observation, it was possible to distinguish epithelium, ciliated cell, absorptive cell and secretory cell in the epidermal layer. The epithelia were columnar and the nucleus was elliptical. The free surface were covered with microvilli. The lateral membranes of epithelium was con nected with neighboring cells by the zonular occludens, zonular adherens and membrane interdigitation. Ciliated cell on free surface had cilia and microvilli, and numerous mitochondria in the apical cytoplasm. In the epidermal layer, it observed 2 type cells having absorptive function. The absorptive cells were columnar in shape, and contained microvilli, pinocytotic vesicles, mitochondria and lysosomes of various electron density. Secretory cells can be divided into four types (A, B, C, D) depending on the cell shape and characteristics of secretory granules. These cells were unicellular glands and had similar characteristics to previously reported on the mantle of the gastropod and bivalves.

• Applied Microscopy
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• v.32 no.3
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• pp.213-222
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• 2002

Histology and ultrastructure of the mantle epidermis in the ark shell, Scapharca broughtonii are described using light and electron microscopy. The mantle of the ark shell is composed of outer epidermis, connective tissue and inner epidermis. Both epidermis are simple and consists of supporting cells, ciliated cells and secretory cells. Connective tissue is composed of mainly collagen and muscle fibers. The supporting cells in the inner epidermis are usually columnar and covered with microvilli. The ciliated cell have cilia and microvilli on the free surface, and numerous tubular mitochondria are observed in the apical cytoplasm. Secretory cells are mainly observed in the outer epidermis, and it can be divided into four types of A, B, C and D with morphological features of the secretory granules. Type A cells of mucous cell are found in the marginal and central mantle. And these cells contains numerous secretory granules of non-bounded and low electron density. Type B cells contains numerous rough endoplasmic reticula, well-developed Golgi complex and secretory granules of membrane-bounded and high electron density. Secretory granules of type C cells are divided into fibrous core layer and homogeneous peripheral layer. Type D cells are found in the outer epidermis of the central and umbonal mantle. And secretory granules of these cells are divided into homogeneous core layer and granular peripheral layer. This results suggest that the outer and inner epidermis of the mantle are related with shell formation and cleaning of the mantle cavity, respectively.

• Journal of the Korean Society of Marine Environment & Safety
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• v.25 no.2
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• pp.220-228
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• 2019

To determine the horizontal and temporal distribution of common squid larvae, Todarodes pacificus (hereafter T. pacificus), we conducted surveys using an IKMT net (mesh size: $500{\mu}m$) with a Fisheries Research Vessel (FRV, TAMGU 21) in the southwestern part of the East Sea in summer (August and September) and autumn (November) 2015. A total of 228 larvae, ranging in mantle length (ML) from 1.4 mm to 21.9 mm, were collected at 35 stations over the research period. The monthly average mantle length of T. pacificus larvae did not differ significantly in August, September and November. (p > 0.05). Catch densities at positive stations ranged between 0.1 and $7.9inds./1,000m^3$ over the research period. Incidence rates of T. pacificus larvae were similar over three months, in the study area (62.9 % - 68.6 %). The 4 - 5 mm mantle length range had the highest frequency in size-frequency distributions for T. pacificus larvae. The larval survival temperature ($15-24^{\circ}C$) at positive stations for catch densities was located below a 20 m depth in August whereas it was located at the surface of the water in September and November. The survival temperature for larvae existed from the bottom to the surface of the water where larvae were sampled larvae in shallow sea areas. However, the larval survival temperature occurred in a shallower location than the upper layer of the thermocline in deep sea areas at a depth below 100 m.

• Proceedings of the Korean Society of Fisheries Technology Conference
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• 2001.10a
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• pp.341-342
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• 2001

이매패류의 아가미는 호흡기능과 함께 점액분비 및 섬모운동 등을 통하여 먹이의 포획, 수송, 소화 기능을 동시에 수행하며 (Beninger et al., 1988). 외부의 물리ㆍ화학적 자극에 빠르게 반응하는 중요한 외투강 기관계이다. 따라서 이매패류 아가미의 구조, 점액분비세포와 섬모운동의 특성은 서식생태와 섭이생태에 따라 다양하므로 이들 아가미에 관한 연구는 주로 다양한 측면의 환경변화 및 섭이생태와 연관하여 수행되어져 왔다. (중략)

• Korean Journal of Fisheries and Aquatic Sciences
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• v.28 no.2
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• pp.163-173
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• 1995

Populations of the common squid, Todarodes pacifirus in the Korean waters were analyzed using the samples taken monthly from February, 1991 to July, 1992. Summer, Autumn and Winter cohorts were arbitrarily established based on frequency distributions of mantle lengths and maturation stages. As cohorts were seperated in mantle length distributions on the basis of accumulated information of size and maturation of T. pacificus, cohorts seperated by the present method were mostly in accord with those by Tanaka's method. But they were not consistent with those by Bhattacharya's and Cassie's methods.

• The Korean Journal of Malacology
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• v.21 no.2 s.34
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• pp.121-132
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• 2005

We investigated the reproductive cycle with gonad developmental phases of Sinonovacula constricta by histological observations, and seasonal changes in biochemical component of the adductor muscle, visceral mass, foot muscle and mantle were studied by biochemical analysis, from January to December, 2004. The reproductive cycle of this species can be classifed into five successive stages: early active stage (March to May), late active stage (May to July), ripe stage (July to September), partially spawned stage (August to October) and spentfinactive stage (October to March). Total protein content was the highest in the following order: adductor muscle, visceral mass, foot muscle, and mantle. Except for mantle, it was generally higher during the ripe and spawning stages, while lower during the spent/inactive stage. There were positive correlations in total protein contents among adductor muscle, foot muscle, and visceral mass. However, the correlations were not statistically significant. Total lipid content was the highest in the visceral mass; it was more than 5 or 6-fold higher than those in the adductor muscle, foot muscle, or mantle. The monthly change was also most dynamic in the visceral mass. It first Increased during the early active stage (March to May), decreased during late active stage (May to July), and then increased again rapidly during the spawning stage (September). There were a strong negative correlation in total lipid contents between foot muscle and adductor muscle (r = -0.634, p = 0.027), and a strong positive correlation between adductor muscle and mantle (r = 0.665, p = 0.018). Glycogen contents showed more or less similar pattern to total lipid contents in the adductor muscle, foot muscle, and visceral mass. It was higher during the early active and spawning stages, while lower during the late active and spent/inactive stages. There was no statistically significant correlation in glycogen contents among different tissues. Especially, total lipid content showed a negative correlationship between the foot muscle, adductor muscle, visceral mass and mantle. Therefore, these results indicate that the nutrient content of the foot muscle, adductor muscle, viseral mass and mantle changed in response to gonadal energy needs.