• The korean journal of orthodontics
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• v.34 no.2 s.103
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• pp.131-142
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• 2004

The movement of tooth-bone segments by osteotomy can simultaneously shift tooth and surrounding alveolar bone in a relatively short period. The purpose of this study was to evaluate the tissue changes in pulp, periodontal ligament, and alveolar bone in rapid tooth-bone movement with osteotomy. The mandibular 3rd premolar of a dog was extracted and cortical bones of the buccal and lingual area were eliminated, and then cortical bones around the mesial and distal area of root, and below the root apex of the mandibular 4th premolar were osteotomized. After a one-week latency period, a tooth-borne distraction device was activated for 6 days. And pulp, periodontal ligament and alveolar bone were evaluated clinically, radiologically, histologically and immunohistochemically at 0, 1, 2, 4, 6, 8 weeks of the consolidation Period and conclusions were roached as follows. 1. Latency period didn't affect total amount or tooth movement and healing process of tissue during consolidation period. 2. Bone formation continued through 8 weeks of consolidation in distracted side, with a high peak at 1-2 weeks, and the lowest at 6-8 weeks or consolidation. 3. At 1 week of consolidation, alveolar bone resorption, osteoclast appearance and inflammatory cell infiltration were the most active, and dentinoclasts characteristically appeared on the pulp and pressure side of the periodontal ligament. 4. The expression of $TGF-\beta$ was area-specific, as it was strong-positive at bone matrix, osteoblast osteoclast of alveolar bone, and dentinoclast inside pulp, but weak in pulp, cementoblast and acellular cementum. 5. The expression of $TGF-\beta$ was generally observed at the initial 1-2 weeks of consolidation at vessels, periodontal ligament cells, and osteoblast near alveolar bone on the distraction side of the periodontal ligament, and was significantly decreased after 6 weeks of consolidation.

• Journal of Chest Surgery
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• v.34 no.10
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• pp.754-762
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• 2001

Background: To evaluate the efficacy of arterial switch operation for transposition of great arteries, serial echocardiographic studies were performed in 8 patients who underwent the surgery between 1989 and 1998 at Dept. of Thoracic & Cardiovascular Surgery, Yeungnam University Hospital in Daegu City, Korea. Material and Method: Follow-up period ranged from 6 months to 11 years(average of 4.1 years). Body weight ranged from 2.6kg to 4.8kg, with average of 3.6kg. 5 of 8 patients were preoperatively diagnosed as TGA+VSD, and 3 as TGA+IVS. LV function was evaluated by the measurement of LV shortening fraction, LVSTI, and LVEF. RVSTI was also measured. Postoperative function of valve and growth of great vessels were analyzed by the measurement of PSPGV, valvular regurgitation, LA/AO ratio, root dimension of aorta and pulmonary artery, comparing with the age matched controls, respectively. Result: LVEF had an average of 65.0+9.03% which is tended to increase serially. LVAOPG had an average of 15.9mmHg. RVPAPG, 27.5mmHg. From the measurement of aortic root dimension of 6 patients at end-systole, aortic root growth was assumed to increase more than the mean value of normal growth. PA root dimension at end-systole showed a similar growth progress when compared with age matched normal controls. Postoperative pulmonic valve regurgitation was noted in 5 of total 8 patients, in which 1 patient who showed grade 2 and 4 showed below grade 1. AR, in 6 patients and all grade 1 Except 1 patient, all the valvular regurgitations were below grade 1, which was presumed to be clinically insignificant.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.9
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• pp.405-411
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• 2019

In this study, tensile tests were carried out on materials (A516-60, A283-C, A285-C, and SB410) for structural and pressure vessels at temperatures of $20^{\circ}C$, $-20^{\circ}C$, and $-40^{\circ}C$, and the changes in the mechanical properties were analyzed. Compared to the results at $20^{\circ}C$, the average yield stress increased by 6.4% and 7.5% at $-20^{\circ}C$ and $-40^{\circ}C$ for A516-60, while the average tensile stress increased by 1.3% and 4.1%, respectively. The average elongation decreased by 4.7% and 20.4% at these temperatures. In the case of A283-C, the average yield stress increased 8.8% and 9.8%, the average tensile stress increased by 4.1% and 5.9%, and the average elongation rate decreased by 7.4% and 9.9% at $-20^{\circ}C$ and $-40^{\circ}C$, respectively. For A285-C, the average yield stress increased by 1.8% and 8.6%, and the average tensile stress increased by 2.6% and 5.3%, respectively, but there was little change in the average elongation. Finally, for SB410, the average yield stress increased by 7.1% and 11.8%, the average tensile stress increased by 4.3% and 5.5%, but the average elongation rate decreased by 8.7% and 13.5%, respectively.