• Journal of the korean society of oceanography
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• v.38 no.2
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• pp.68-79
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• 2003

Although seagrasses are relatively abundant, few studies have been conducted on seagrass physiology and ecology in Korea. Zostera marina is the most abundant seagrass species, widely distributed throughout all coastal areas of the Korean peninsula. To examine seasonal dynamics and spatial variations of eelgrass, Zostera marina distributed on the coast of Korea, morphological characteristics, biomass, tissue nutrient constituents, leaf productivity and environmental factors were monitored monthly from the eelgrass beds in Kabae Bay and Kosung Bay on the south coast of the Korean peninsula from June 2001 to June 2002. Eelgrass density, biomass, morphological characteristics, leaf productivities, and tissue nutrient constituents exhibited clear seasonal variations, and these seasonal trends reflected seasonal changes in water temperature. Eelgrass shoot density and biomass at Kabae Bay site showed more obvious seasonal trends than Kosung Bay. No strong seasonality in Kosung Bay site appeared to be caused by high water temperature ($>30{\circ}C$) during summer months at this site. Despite differences in nutrient availabilities between two study sites, eelgrass biomass and leaf productivities were not significantly different between study sites, and this lack of spatial variations implies that the ambient nutrient availabilities at the present study sites are in excess of seagrass nutrient demand. Eelgrass tissue N content and sediment pore water DIN concentrations exhibited reverse relationship at the present study. This reverse relationship suggests in situ nutrient concentrations are not good indicator of nutrient availabilities, and regeneration and turnover rates of sediment nutrients are also important factors to determine nutrient availabilities at the site.

• Journal of Aquaculture
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• v.18 no.4
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• pp.252-259
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• 2005

Isozyme and AFLP analyses were examined to estimate the utilities of them as a genetic marker. The utilities were evaluated by genetic divergence and relationships among the four distinct abalone species; Haliotis discus hannai collected from northeast coast of Japan and Yellow-Sea coast of China, H. rufescens collected from west coast of USA, H rubra collected from southeast coast of Australia and H midae collected from Cape Town of South Africa. Isozyme and AFLP analyses showed a clear genetic divergence between every pair of species. Genetic relationships among the low species estimated by isozyme and AFLP analyses reflected to geographical distribution and morphological characteristics. In conclusion, Isozyme and AFLP analyses are suitable genetic markers far estimates of genetic divergence and relationship among abalone species.

• The Korean Journal of Malacology
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• v.17 no.1
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• pp.1-6
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• 2001

The genetic relationship was examined with PCR-RAPD markers among three scallop species, Chlamys farreri farreri, Patinopecten yessoensis, and Agropecten irradians. Six primers were selected from 60 primers used to compare PCR-RAPD profiles among species. All primers showed distinct RAPD band patterns between the three species. In Chiamys farreri farreri, the morphological characteristics such as shell size and color were considerably different between the two geographical populations. RAPD profile, however, showed that no significant genetic differences were found between the two geographical populations. Polymorphic alleles were observed within a population of each species. Thus, PCR-RAPD markers are useful in identifying scallop species and in understanding scallop population genetic structure.

• Korean Journal of Agricultural Science
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• v.43 no.2
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• pp.240-248
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• 2016

Radish is a common vegetable consumed in Korea, Japan, and China. Radish Breeding has been conducted based on morphological properties, such as shape and color. Recently, physicochemical properties of radish are attracting more attention from breeders to develop cultivars for the retail market. In this study, major components of radish were determined and their relationship with textural property analyzed. Sixty-six radish cultivars were selected and divided into white head (WH) and green head (GH) according to their head color. The cutting forces of GH and WH groups were $2.17{\pm}0.34kg$ and $2.31{\pm}0.36kg$, respectively (P > 0.05). The starch contents of GH and WH were $3.75{\pm}0.39g\;per\;100g$ (dry basis) and $4.24{\pm}0.62g$, respectively. Cellulose contents in both groups were similar at 12.3-12.4 g per 100 g (dry basis). Pearson correlation coefficients between cutting force, cellulose content, and starch content ranged from -0.33-0.326 which does not demonstrate any strong correlation between these components. Therefore, no relationship was found between the cutting force and the starch content or the cellulose content for the cultivars analyzed in this study. As the first intensive study on the texture and the major components of radish, these results could provide valuable information for radish breeding if further studies on taste and nutrient components are conducted.

• Journal of Plant Biology
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• v.33 no.1
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• pp.1-24
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• 1990

This study was attempted to clarify the taxonomic problems that have been raised up to now in the study o section Telephium, genus, Sedum: the delimitation of taxa belong to Telephium group, their relationship, and nomenclatural confusion and the rank of Telephium group. Specimens were collected at 19 sites in Korea. The habitat, distribution, external morphological characters of habit, leaf shape, phyllotaxy, inflorescence, color of floral organs, floral formula, carpel, capsule, and micro-characters of pollen, seed coat, stigma and anther with SEM were examined. Through this study, the following results were obtained. The delimitation of taxa that belong to section Telephium in Korea and their relationship Nomenclatural errors were corrected. In S. rotundifolium Lee, species epithet“rotundifolium”is later homonym of s. rothundifolium Lamarck, so corrected to S. duckbongii Chung and Kim by article 64 of ICBN. Phyllotaxy was elucidated to meaningless, character in sect. Telephium. S. taquetii was a separate species from S. viridescens and not of its synonym. S. alboroseum Baker in Korea was S. erythrostictum sensu Master not of S. erythrostictum Miquel. By this study , taxa of sect. Telephium in Korea were arranged to 7 species. Considering interspecific relationship of sect. Telephium, S. duckbongii and S. alboroseum are considered to be more advanced forms and S. viridescens, S. taquetii, and S. viviparum to be more primitive forms among 7 species.

• Journal of Medicine and Life Science
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• v.15 no.1
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• pp.12-15
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• 2018

Digastric and stylohyoid muscles are located in the suprahyoid region. There have been few studies about the general morphology of stylohyoid muscle and its relationship with digastric muscle. During routine educational dissection, unusual insertion of bilateral stylohyoid muscle was found in the cadaver of a 92-year-old Korean male, whose cause of death was 'aspiration pneumonia'. Stylohyoid muscle arose from the styloid process, and inserted onto the intermediate tendon of digastric muscle and the hyoid bone on both sides. Each digastric muscle normally consists of an anterior belly, intermediate tendon and a posterior belly. In this cadaver, there were two anterior bellies on right side while one anterior belly was found on left side. Stylohyoid muscle ran medial to the intermediate tendon of digastric muscle on both sides. The anatomical relationship between stylohyoid and digastric muscles was reviewed based on morphological and embryological point of view.

• ALGAE
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• v.32 no.2
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• pp.87-100
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• 2017

The genera Hypnea and Calliblepharis of the family Cystocloniaceae are discriminated by their female reproductive structure, especially in the formation of carposporangia and gonimoblasts. Hypnea saidana, once classified based on obsolete evidence, has not been studied phylogenetically using molecular analysis and detailed reproductive structure though it shares many morphologic features with the genus Calliblepharis. To provide better understanding of generic relationship of H. saidana with Hypnea and Calliblepharis, we carried out molecular analyses using the nuclear-encoded small subunit ribosomal DNA (SSU) and chloroplast-encoded large subunit of the RuBisCO (rbcL), and exact morphological observations focusing on the reproductive structures of wild specimens. Our molecular phylogeny showed that H. saidana is closely related to Calliblepharis, but distinct from the clade of Hypnea. Female reproductive structure of H. saidana characterized by upwardly developing chains of carposporangia, central reticulum of cell, and gonimoblast filaments not connected to the pericarp provides definite evidence to assign the taxonomic position of this species to Calliblepharis. Based on our combined molecular and morphological analyses, we have proposed Calliblepharis saidana comb. nov., expanding the distribution of Calliblepharis habitat from the eastern Atlantic South Africa, the northern Indian Ocean, Australasia, and Brazil to the western Pacific Ocean.

• Parasites, Hosts and Diseases
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• v.55 no.1
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• pp.47-54
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• 2017

The prevalence of cercarial infection in freshwater snails and their evolutionary trends were studied in Nakhon Nayok province, Thailand. A total of 2,869 individual snails were examined for parasitic infections. The results showed that 12 snail species were found to host larval stages of trematodes with an overall prevalence of 4.7%. The infected specimens included 7 types at the cercarial stage; cercariae, megalurous cercariae, echinostome cercariae, furcocercous cercariae, parapleurolophocercous cercariae, virgulate cercariae, and xiphidiocercariae. Regarding molecular identification, ITS2 sequence data of each larval trematode were analyzed, and a dendrogram was constructed using the neighbor-joining method with 10,000 replicates. The dendrogram was separated into 6 clades (order/family), including Echinostomatida/Echinostomatidae, Echinostomatida/Philophthalmidae, Opisthorchiida/Heterophyidae, Plagiorchiida/Prosthogonimidae, Plagiorchiida/Lecithodendriidae, and Strigeatida/Cyathocotylidae. These findings were used to confirm morphological characteristics and evolutionary trends of each type of cercariae discovered in Nakhon Nayok province. Furthermore, this investigation confirmed that the ITS2 data of cercariae could be used to study on phylogenetic relationships or to determine classification of this species at order and/or family level when possible.

• Journal of Chest Surgery
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• v.17 no.3
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• pp.362-370
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• 1984

The term corrected transposition of great arteries [hereafter referred to as corrected TGA] of the heart in which there is both a discordant atrio-ventricular relationship and transposition of the great vessels. Usually situs solitus is present, while the ventricles are inverted showing an l -loop. The great vessels are transposed and in the l-position so that the pulmonary artery arises from the right-sided morphological left ventricle and the anteriorly l- transposed aorta arises from the left-sided morphological right ventricle yielding an SLL pattern. In the majority of cases, associated lesions are common. The most frequent are ventricular septal defect, obstruction to the pulmonary outflow tract, tricuspid valve incompetence and atrio-ventricular conduction abnormalities. In the rare cases, no associated conditions are present and hemodynamic pathways are normal. In the report, we present one case of a 20 year-old male having corrected TGA associated with severe tricuspid valve incompetence, was corrected by tricuspid valve replacement, directly developed a supra-ventricular tachycardia but was controlled by calcium-entry blocker, verapamil, successfully.

• The Korean Journal of Physiology
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• v.4 no.2
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• pp.19-24
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• 1970

Since the discovery of the muscle spindle by Hassall (1831), an intensive studies of its anatomical and physiological characteristics had been undertaken. Recent morphological studies of Boyd (1962) demonstrated that the muscle spindles have two different intrafusal muscle fibers, nuclear bag and nuclear chain fiber, and these intrafusal fibers are under independent motor innervation by ${\gamma}_1$ and ${\gamma}_2$ motor neurone. Neurophysiological studies of Hunt and Kuffler (1951) showed regulatory effect of ${\gamma}$ motor neurone upon the excitability of the spindle afferents. Harvey and Mathews (1961) observed the dynamic and static characteristics of the two different spindle afferents, the primary and secondary ending. Furthermore, Mathews (1962) postulated the functional existance of two kind of ${\gamma}$ motor neurones, namely, the dynamic and static fusimotor fiber. Recent report of Kim and Partridge(1969) pointed out that the descending vestibular signals had increased the slope of the length-tension relationship in stretch reflex; Kim (1967) demonstrated that the descending vestibular impulses act upon the stretch reflex loop through the ${\gamma}$ motor pathway. These experimental evidences from the morphological and neurophysiological studies on the muscle spindles support the concept that the stretch reflex action of the skeletal muscle operates as a negative feedback control system. The author had discussed the way by which the f system participates in the control of stretch relfex feed back system. that was taken for a prototype of posture and movement.