• Proceedings of the Korean Society of Developmental Biology Conference
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• 2003.10a
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• pp.24-25
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• 2003

The zebrafish (Danio rerio) is now the pre-eminent vertebrate model system for clarification of the roles of specific genes and signaling pathways in development. I will talk about positional cloning of two developmental mutants in zebrafish. The first mutant is headless: The vertebrate organizer can induce a complete body axis when transplanted to the ventral side of a host embryo by virtue of its distinct head and trunk inducing properties. Wingless/Wntantagonists secreted by the organizer have been identified as head inducers. Their ectopic expression can promote head formation, whereas ectopic activation of Wnt signalling during early gastrulation blocks head formation. These observations suggest that the ability of head inducers to inhibit Wntsignalling during formation of anterior structures is what distinguishes them from trunk inducers that permit the operation of posteriorizing Wnt signals. I describe the zebrafish headless (hdl) mutant and show that its severe head defects are due to a mutation in T-cell factor-3 (Tcf3), a member of the Tcf/Lef family. Loss of Tcf3 function in the hdl mutant reveals that hdl represses Wnt target genes. I provide genetic evidence that a component of the Wntsignalling pathway is essential in vertebrate head formation and patterning. Second mutant is mind bomb: Lateral inhibition, mediated by Notch signaling, leads to the selection of cells that are permitted to become neurons within domains defined by proneuralgene expression. Reduced lateral inhibition in zebrafish mib mutant embryos permits too many neural progenitors to differentiate as neurons. Positional cloning of mib revealed that it is a gene in the Notch pathway that encodes a RING ubiquitin ligase. Mib interacts with the intracellular domain of Delta to promote its ubiquitylation and internalization. Cell transplantation studies suggest that mib function is essential in the signaling cell for efficient activation of Notch in neighboring cells. (중략)

• Journal of Nutrition and Health
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• v.32 no.2
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• pp.150-157
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• 1999

This study explored the effects of dietary calcium levels and/or ovariectomy on bone formation, bone composition and calcium metabolism using female Sprague-Dawley weanling rats(mean body weight$\pm$SEM : 232.3$\pm$6.7g) as a model. Rats received high(1.5%) calcium diets for eight weeks during the growth period and were randomly assigned to ovariectomy and sham groups. The two groups were than each randomly divided into three sub-groups and fed 0.1%, 0.5% and 1.5% calcium diets for eight weeks after operation. The results indicate that body weight gain was higher in ovariectomy groups than sham groups regardless of dietary calcium levels and food intakes. Serum Ca concentration was decreased in low Ca groups after operation and serum P concentration increased in ovariectomy groups. Serum Ca concentration was decreased in low Ca groups after operation and serum P concentration increased in ovariectomy groups. Serum alkaline phosphatase activity was increased in ovariectomy groups and was not influenced by dietary calcium levels after operation. Urinary hydroxyproline decreased in high Ca intake groups regardless of whether rats had received an ovariectomy or not. The weight, length and breaking force of the femur were not significantly different in all groups. Ash, calcium, phosphate and magnesium contents in the femur and lumbar were not significantly different regardless of ovariectomy operation and dietary calcium levels. But high/normal calcium intake after ovariectomy and sham operation increased the weight and calcium content in bone. Therefore, high calcium intake influenced the formation of peak bone mass during the growth period and calcium levels and calcium levels and calcium levels continued to influence bone growth and composition after ovariectomy.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.44 no.2
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• pp.79-85
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• 2018

Objectives: The aim of this study was to evaluate the effects of herbal extracts on bone regeneration. Two known samples were screened. Materials and Methods: We previously established a rat calvaria defect model using a combination of collagen scaffold and herbal extracts. An 8 mm diameter trephine bur with a low-speed dental hand piece was used to create a circular calvaria defect. The experimental group was divided into 4 classifications: control, collagen matrix, Danshen with collagen, and Ge Gan with collagen. Animals in each group were sacrificed at 4, 6, 8, and 10 weeks after surgery, and bone regeneration ability was evaluated by histological examination. Results: Results revealed that both Danshen and Ge Gan extracts increased bone formation activity when used with collagen matrix. All groups showed almost the same histological findings until 6 weeks. However, after 6 weeks, bone formation activity proceeded differently in each group. In the experimental groups, new bone formation activity was found continuously up to 10 weeks. In the Danshen and Ge Gan groups, grafted materials were still present until 10 weeks after treatment, as evidenced by foreign body reactions showing multinucleated giant cells in chronic inflammatory vascular connective tissue. Conclusion: Histological analyses showed that Danshen and Ge Gan extractions increased bone formation activity when used in conjunction with collagen matrix.

• The Korean Journal of Zoology
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• v.29 no.1
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• pp.1-12
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• 1986

Electrophoretic, immunological, and column chromatography methods were used to determine the appearance and distribution of storage proteins in various organs during the metamorphosis of Bombyx mori L. Two storage proteins start to appear in haemolymph in early 5th instar stage and show the identical mobility with fat body proteins. These proteins show the high concentration in haemolymph in last instar stage but accumulate in fat body after pupation. Storage protein-2 shows the distinct pattern for general storage proteins in both male and females. This protein is involved with the formation of cuticle protein in late last instar stage and appears to be temperally deposited in midgut during the pupal stage. Also SP-2 shows the identity with vitellogenin electrophoretically and immunologically and especially the positive reaction with antibody against yolk protein during the pupal stage, demonstrating that the storage protein is closely related to the formation of yolk protein.

• The Bulletin of The Korean Astronomical Society
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• v.37 no.1
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• pp.39.2-39.2
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• 2012

We present our study on a comparison of dark matter halo merger history from the runs using different numerical simulation codes. To analyze the uncertainty caused by the use of different N-body calculation methods, we compare the results from two cosmological hydrodynamic simulation codes GADGET-2 and RAMSES, which use a TreePM algorithm and the Adaptive Mesh Refinement(AMR) technique respectively. We perform cosmological dark matter-only simulations with the same parameter set and initial condition for both. The dark matter halo mass functions from two simulation runs correspond well with each other, except for lower mass haloes. The discrepancy on the low-mass haloes in turn causes a notable difference in halo merger rate, especially for the case of extremely minor merger. The result from GADGET-2 predicts that most haloes undergo more number of mergers with small haloes than that from RAMSES, independent of halo mass and environment. However, in the context of the study on galaxy evolution, such extreme minor mergers generally do not have strong effects on galaxy properties such as morphology or star formation history. Hence, we suggest that this uncertainty could be quantitatively negligible, and the results from two simulations are reliable even with only minor difference in merger history.

• Journal of the Korean Society of Clothing and Textiles
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• v.31 no.8
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• pp.1297-1309
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• 2007

The purpose of this study is to investigate the effect of shirt color, tie color, tone, perceiver' gender on impression formation by applying tone-in-tone coloration of shirt and necktie: coloration of two colors. This experiment was designed to utilize the $2{\times}6{\times}4{\times}2$ factorial designs. and they are shirt color(red, blue), tie color(red, yellow red, yellow, green, blue, purple), tone(vivid, light, dull, dark), and perceiver' gender(a male, a female). The experimental materials developed for this study were a set of stimulus and response scales. The stimuli were 48 upper body photographs which were color outputs by CAD system(4D-box program). The subjects of this research were 288 male and 288 female college students. There were established impression dimension from factor analysis 27 bi-polar adjectives and investigated the effect of interaction between each variable affected impression formations. The items of the adjectives are classified into 4 Impression dimensions: activity, potency, attractiveness, and tenderness. Shirt color, tie color, tone, and perceiver' gender influenced on impression formation. Specially, tie color and tone influenced on the 4 impression dimension greatly by interaction as well as independently. As a result tie is very important clue of impression formation in tone-in-tone coloration of shirt and necktie. Even though tie occupies only a small area in men's clothes it has great effect since it is close to the face.

• The Korean Journal of Zoology
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• v.16 no.1
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• pp.13-23
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• 1973

The changes in the quantitative distribution and in cytoplasmic granules of tongue mast cells and duodenal enterochromaffin cells in male albino rats were observed following oral administration of 40mg/kg body wt. isonicotinic acid hydraside (INH) and 20mg/kg body wt. pyridoxine. The results obtained are summarized as follows: 1. INH administered-rat showed a marked decrease in the number of mast cells, caused by leakage of cytoplasmic granules, while pyridoxine-rat showed increased the number of mast cells. 2. Similarly, INH-rat showed a marked decrease in the number of enterochromaffin cells. In the case of pyridoxine-rat, however, the number of enterochromaffin cells increased compared with that of the controls. 3. In view of the fact that a large dose of INH was harmful to the formation of mast cells and enterochromaffin cells. And considering that a moderate dose of pyridoxine stimulated the formation of the two kinds of cells and the amounts of cytoplasmic granules, it was concluded that pyridoxine might be concerned with the metabolism of secretory products, 5-Hydroxytryptamine.

• Journal of Astronomy and Space Sciences
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• v.25 no.3
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• pp.239-244
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• 2008

Two kinds of important issues on Titius-Bode's relation have been discussed up to now: one is if there is a simple mathematical relation between distances of natural bodies orbiting a central body, and the other is if there is any physical basis for such a relation. These may be tackled by answering a question whether Titius-Bode's relation is valid universally in exo-planetary systems. We have examined whether Titius Bode's relation is also applicable to exo-planetary systems by statistically studying the distribution of the ratio of rotational periods of two planets in an exo-planetary system, 55 Cnc, by comparing it with that derived from Titius-Bode's relation. We find that the distribution of the ratio of rotational periods of randomly chosen two planets in the 55 Cnc system is apparently inconsistent with that derived from Titius-Bode's relation. The probability that two data sets are drawn from the same distribution function is 50%. We also find that the Fourier power spectra show that the distribution of the semi-major axis of planets in the 55 Cnc system seems to be stretched. We conclude by pointing out that large numbers of planets should be examined to more convincingly explain the distribution of the distance of planetary formation regions.

• Imaging Science in Dentistry
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• v.34 no.1
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• pp.35-48
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• 2004

Purpose: To investigate the effect of rhBMP-2 on the healing of bone defect in the low calcium diet rat. Materials and Methods: To prepare the experimental model, control group was fed a normal diet and experimental group was fed a low calcium diet for 3 weeks. And then, 4 mm bicortical perforated bone defect was made on mandibular body of each rats. Experimental group was subdivided into two groups; experimental group 1 (rats given a low calcium diet before and after bone defect) and experimental group 2 (rats given a low calcium diet before and after bone defect with rhBMP-2 application). At 1, 3, 5 and 7 weeks after bone defect formation, the rats were terminated. The healing of bone defect was assessed by three-dimensional computerized tomography, soft x-ray radiography, and histopathological examination. Results : The wound healing of the bone defect for control group, experimental group 1, and experimental group 2 showed a increase from 3 weeks after bone defect formation. The experimental group 2 showed a more increase in healing amount than control group and experimental group 1 from 5 weeks after bone defect formation and the experimental group 2 showed a complete recovery of bone defect at 7 weeks after bone defect formation. Conclusion: The healing process of bone defect is accelerated by rhBMP-2 application in the low calcium diet rats.

• Molecules and Cells
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• v.21 no.3
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• pp.436-442
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• 2006

Different proliferation of neuroblast 6-4 (NB6-4) in the thorax and abdomen produces segmental specific expression pattern of several neuroblast marker genes. NB6-4 is divided to form four medialmost cell body glia (MM-CBG) per segment in thorax and two MM-CBG per segment in abdomen. As homeotic genes determine the identities of embryonic segments along the A/P axis, we investigated if temporal and specific expression of homeotic genes affects MM-CBG patterns in thorax and abdomen. A Ubx loss-of-function mutation was found to hardly affect MM-CBG formation, whereas abd-A and Abd-B caused the transformation of abdominal MM-CBG to their thoracic counterparts. On the other hand, gain-of-function mutants of Ubx, abd-A and Abd-B genes reduced the number of thoracic MM-CBG, indicating that thoracic MM-CBG resembled abdominal MM-CBG. However, mutations in Polycomb group (PcG) genes, which are negative transregulators of homeotic genes, did not cause the thoracic to abdominal MM-CBG pattern transformation although the number of MM-CBG in a few percent of embryos were partially reduced or abnormally patterned. Our results indicate that temporal and spatial expression of the homeotic genes is important to determine segmental-specificity of NB6-4 daughter cells along the anterior-posterior (A/P) axis.