• 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)

• 한국전산유체공학회:학술대회논문집
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• 1997.10a
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• pp.143-148
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• 1997

Differential pressure Venturi cone flowmeter is an advanced flowmeter which has many advantages such as wide range of measurement, high accuracy, excellent flow turndown ratio, low headless, and short installation pipe length requirement, etc. Like other differential pressure flowmeter, Venturi cone flowmeter uses the law of energy conservation, but its shape and position make it perform better than others. The cone acts as its own flow conditioner and mixer, fully conditioning and mixing the flow prior to measurement. For the analysis, we use Reynolds-averaged Navier-Stokes equations and $k-{\omega}$ turbulence model. The equations are fully trans-formed in the computational coordinates, the pressure-velocity coupling is made through SIMPLER algorithm, and the equations are discretized using analytic solutions of the linearized equations(Finite Analytic Method). At the end of the paper, using the result of analysis, We propose a new shape of cone with the hope of drag reduction and high performance.

• Korean Journal of Child Studies
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• v.13 no.1
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• pp.125-138
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• 1992

The purpose of the present study was to examine the development of embedding through relative clause formation in the first language acquisition of Korean. Results are reported from the study of the spantaneous natural speech of 36 young Korean children ranging from 16 months to 45 months in age acquiring Korean as their first language in Chinju, Korea. The results revealed a developmental order in the first language acquisition of Korean relative clause structures. Namely, a free or headless relative clause appears to be acquired first, before lexically headed restrictive relative construction. This order is consistent with one evidenced in English (and also Chinese) first language acquisition, 'free' relatives appear to provide a developmentally early stage in the acquisition of restrictive relative clauses. The Korean data provided additional evidence for an intermediary stage with an overt complementizer as well as an overt lexical head. Implications for the results are disscused with regard to a continuous theory of universal grammar in the first language acquisition.

• Journal of Korean Foot and Ankle Society
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• v.17 no.2
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• pp.106-114
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• 2013

Purpose: Posteroanterior screw fixation is biomechanically stronger than anteroposterior screw fixation. However, there are few literature about the correlation between clinical results and more strength by posteroanterior fixation. This study was performed to evaluate the clinical outcomes of the accelerated rehabilitation following anterior open reduction and posterior percutaneous screw fixation for displaced talar neck fractures. Materials and Methods: Eighteen cases were followed up for more than 1 year after posteroanterior fixation using headless compression screw for talar neck fractures. The clinical evaluation was performed according to American Orthopaedic Foot and Ankle Society (AOFAS) score and Hawkins criteria. As radiographic evaluation, the degree of fracture displacement, period to union, and occurrence rate of complications such as avascular necrosis through MRI were measured. Results: The AOFAS score was average 90.4 points at the last follow-up. There were 7 excellent, 9 good, and 2 fair results according to the Hawkins criteria. Therefore, 16 cases(88.8%) achieved satisfactory results. The degree of fracture displacement had improved significantly from preoperative average 5.6 mm to 1.2 mm immediate postoperatively, and maintained to 1.1mm at the last follow-up. All cases achieved bone union, and the period to union was average 12.4 weeks. There were 3 cases of avascular necrosis of talar body and 2 cases of post-traumatic arthritis. Conclusion: Anterior open reduction and posterior percutaneous headless screw fixation seems to be an effective surgical method for displaced talar neck fractures, because of the possibility of accurate restoration of articular surface, fixation strength enough to early rehabilitation, and needlessness of hardware removal.

• Journal of Korean Foot and Ankle Society
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• v.16 no.4
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• pp.247-256
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• 2012

Purpose: This study was performed to evaluate the clinical outcomes of operative treatment using mini-open sinus tarsi approach for displaced intraarticular calcaneal fractures. Materials and Methods: We studied 18 cases (16 patients) of intraarticular calcaneal fractures who were treated with sinus tarsi approach by same surgeon. The mean age of patients was 44.8 years, and mean follow-up period was 17.2 months. The measurement of B$\ddot{o}$hler angle, Gissane angle, the degree of articular surface depression, and the period to union were performed through preoperative and postoperative radiographs. The clinical evaluation was performed according to hindfoot score of the American Orthopaedic Foot and Ankle Society (AOFAS) and scale of the Creighton-Nebraska health foundation (CNHF). Results: B$\ddot{o}$hler angle and Gissane angle had improved significantly from preoperative average $9.8^{\circ}$, $117.6^{\circ}$to average $22.4^{\circ}$, $113.4^{\circ}$ immediate postoperatively, and had maintained to average $21.8^{\circ}$and $114.2^{\circ}$ at the last follow-up. The degree of articular surface depression had improved significantly from preoperative average 5.2 mm to 1.2 mm at the last follow-up. All cases achieved bone union, and the period to union was average 10.5 weeks. AOFAS score was average 86.2 points at the last follow-up. There were 7 excellent, 9 good, and 2 fair results according to the CNHF scale. Therefore, 16 cases (88.8%) achieved satisfactory results. Conclusion: The minimally invasive sinus tarsi approach using headless compression screw seems to be an effective surgical method for displaced intraarticular calcaneal fractures, because of the possibility of accurate restoration of articular surface and the low risk of postoperative soft tissue complications.

• Conservation Science in Museum
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• v.30
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• pp.47-70
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• 2023

In 2019, the first excavation survey was conducted at the Temple Site No. 4 of Yaksugok Vally in Namsan Mountain, Gyeongju to determine the original location of the headless stone Buddha statue and the structure of the temple site. The survey excavated a stone Buddha head that was confirmed in a comparative analysis to be petrologically and mineralogically identical to a headless stone seated Buddha statue found derelict nearby. Traces of gold leaf and black adhesive were found on a portion of the right side of the face of the Buddha head buried in the ground. Since it is exceedingly rare for lacquer and gilding techniques to have been applied to a large stone Buddha statue without a base layer, this study examines the gilding techniques of the time by analyzing the characteristics of the materials used. In this process, the structure of the gold foil was observed through analytical microscopy and scanning electron microscopy with energy dispersive X-ray spectrometry, and the gold (Au) component was identified. As a result of analyzing the black adhesive using pyrolysis-gas chromatograph/mass spectrometry (pyrolysis-GC/MS), pyrolysis compounds such as hydrocarbons, fatty acids, catechol, and catechol oxidation products were detected. This was identical to the characteristics identified upon analyzing lacquer collected from species of lacquer tree whose main component is urushiol. Therefore, it was confirmed that the stone Buddha head excavated from the Temple Site No. 4 of Yaksugok Valley was separated from a nearby stone seated Buddha statue, and that the gold foil was attached using lacquer sap collected from lacquer trees, which grow in Korea, China, and Japan.

• Journal of Korean Society of Water and Wastewater
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• v.19 no.5
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• pp.565-571
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• 2005

The method to decide media sphericity on the filter has been investigated. The sphericity, the ratio of the surface area of an equal volume sphere to the real surface area of the particles, is one of major physical characters of media affecting the bed expansion during backwash. The media in each treatment plant may have different sphericity, and the sphericity of the media in the filter may be changed as backwashing has been conducted regularly for a long time. Media from twelve water treatment plants under KOWACO have been collected and selected to insure various and practical sphericities. The sphericity of each media has been calculated by using well known equations. For example, Kozeny equation, Dahmarajah equation and so on. The experiment results have indicated that the sphericity of each water treatment plant is different. Although the sphericity values measured by different methods were turned out to be diverse values, the order in the magnitude seemed to be the same. The sphericity values of sand media were in the range of 0.71-0.82 and those of anthracite were placed between 0.49 and 0.56 by the Dharmarajah equation.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.10 no.6
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• pp.714-720
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• 1998

The differential pressure venturi-cone flowmeter is an advanced flowmeter which has many advantages such as wide range of measurement, high accuracy, excellent flow turn-down ratio, low headless, short installation pipe length requirement, and etc. Like other differential pressure flowmeters, the venturi-cone flowmeter uses the law of energy conservation, but its shape and position make it perform better than others. The cone acts as its own flow conditioner and mixer, fully conditioning and mixing the flow prior to measurement. For the analysis, we used Reynolds-averaged Wavier-Stokes equations and k-$\omega$ turbulence model. The equations were fully transformed into the computational domain, the pressure-velocity coupling was made through SIMPLER algorithm, and the equations were discretized using finite analytic solutions of the liberalized equations(Finite Analytic Method). To control the separation phenomenon on the cone surface, we proposed a new shape of cone, and analyzed the flowfield in the new flowmeter system, and found the improvement on the performance of the new cone flowmeter.

• Parasites, Hosts and Diseases
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• v.58 no.4
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• pp.457-460
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• 2020

The Pacific tapeworm Adenocephalus pacifcus (syn. Diphyllobothrium pacificum) is a causative agent of diphyllobothriosis occurred in Pacific coast of South America, mainly in Peru. Source of infections are traditional meal from raw or undercooked marine fish such as "cebiche". We confirmed 3 new cases, one including scolex and the other two headless. A strobila 46 cm long without scolex was discharged from an 8-year-old boy before treatment. Specimens were confirmed morphologically by presence of tegumental protuberances on proglottids and small sized eggs. Partial sequence of cytochrome c oxidase subunit 1 gene was congruent with A. pacificus sequences.

• Journal of Korean Foot and Ankle Society
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• v.12 no.1
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• pp.14-19
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• 2008

Purpose: We tried to understand the effects of the derotational closing wedge Akin osteotomy during the operation for the hallux valgus with pronation of great toe. Materials and Methods: Eighty five patients who had undergone Akin osteotomy among the eighty seven patients who had been treated with Scarf osteotomy with hallux valgus were included in this study. Derotational supination was added on the medial closing wedge Akin osteotomy at the base of proximal phalanx and it was secured with K-wire, headless screw or staple. We measured and analyzed pre- and post-operative hallux primus valgus angle and hallux pronational rotatory angle. Results: The hallux primus valgus angle improved an average of $14{\pm}2.98$ degrees to $-1{\pm}1.68$ degrees with the hallux pronational rotatory angle respectively from $24.8{\pm}7.64$ degrees to $4.7{\pm}4.22$ degrees. Conclusions: After the metatarsal osteotomy for the treatment of the hallux valgus with the pronation of great toe, derotational closing wedge Akin osteotomy can give us a belief that it can correct the hallux primus valgus angle and hallux pronational rotatory angle also and it can be a helpful method for minimizing the recurrence rate of the hallux valgus deformity.