• Journal of Periodontal and Implant Science
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• v.29 no.1
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• pp.153-171
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• 1999

The purpose of this study was to evaluate the effect of modified calcium sulfate paste on periodontal regeneration. l-wall intrabony defect(mesio-distal width: 4mm, depth: 4mm) was surgically created on the distal side of P2 and mesial side of p4 in four dogs. The control group(GFS) was treated with conventional flap operation alone, and the experimental group(CS) was treated with conventional flap operation with modified calcium sulfate paste application. Both control and experimental groups were sacrificed after 8weeks of healing period, The results of histological and histometric observations were as follows. 1. The length of the junctional epithelium was 0.41${\pm}$0.01mm in the control groups, 0.47${\pm}$0.01mm in the experimental group. 2. The connective tissue attachment was 0.28${\pm}$0.02mm(6.15${\pm}$0.28%) in the control group, 0.18${\pm}$0.01mm(3.41${\pm}$0.14%) in the experimental group. The control group showed more connective tissue attachment. 3. The new cementum formation was 3.80${\pm}$0.06mm(84.80${\pm}$0.33%) in the control group, 4.49${\pm}$0.06mm(87.57${\pm}$0.15%) in the experimental group. Both groups showed a lot of new cementum formation. 4. The new bone formation was 1.43${\pm}$0.03mm(32.37%) in the control group, 2.04${\pm}$O.09mm(40.94%) in the experimental group. 5. The inflamatory cells were observed partially around resorbed calcium sulfate in the connective tissue of the experimental group. 6. Partially resorbed calcium sulfate were found within the connective tissue, around alveolar bone, and in the newly formed alveolar bone, On the basis of these results, newly formed calcium sulfate paste enhanced new bone formation and new cementum formation. The resorption rate of calcium sulfate seems to be controlled by the add-in compounds. Thus research about biocompatibility and adequate resorptionrate is required to develop a improved material.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.12 no.6
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• pp.299-303
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• 2002

The relationship of crystallinity between defects distribution with (100) ZnTe/GaAs using HWE growth was investigated by four crystal rocking curve (FCRC) and transmission electron microscopy (TEM). The thickness dependence of crystal quality in ZnTe epilayer was evaluated. The FWHM value shows a strong dependence on ZnTe epilayer thickness. For the films thinner than 6 ${\mu}{\textrm}{m}$, the FWHM value decreases very steeply as the thickness increases. For the films thicker than 6 ${\mu}{\textrm}{m}$, it becomes an almost constant value. At the thickness of 12 $\mu\textrm{m}$ with the smallest value of 66 arcsec. which is the best value so far reported on ZnTe epilayers was obtained. Investigation into the nature and behavior of dislocations with film thickness in (100) ZnTe/(100)GaAs heterostructures grown by Hot Wall Epitaxy (HWE). This film defects range from interface to 0.7 ${\mu}{\textrm}{m}$ thickness was high density, due to the large lattice mismatch and thermal expansion coefficients. The thickness of 0.7~1.8 ${\mu}{\textrm}{m}$ was exists low defect density. In the thicker range than 1.8 ${\mu}{\textrm}{m}$ thickness was measured hardly defects.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.11a
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• pp.120-123
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• 2003

The ZnSe epilayers were grown on the GaAs substrate by hot wall epitaxy. After the ZnSe epilayers treated in the vacuum-, Zn-, and Se-atmosphere, respectively, the defects of the epilayer were investigated by means of the low-temperature photoluminescence measurement. The dominant peaks at 2.7988 eV and 2.7937 eV obtained from the PL spectrum of the as-grown ZnSe epilayer were found to be consistent with the upper and the lower polariton peak of the exciton, $I_2$ ($D^{\circ}$, X), bounded to the neutral donor associated with the Se-vacancy. This donor-impurity binding energy was calculated to be 25.3 meV. The exciton peak, $I_1^d$, at 2.7812 eV was confirmed to be bound to the neutral acceptor corresponded with the Zn-vacancy. The $I_1^d$ peak was dominantly observed in the ZnSe/GaAs:Se epilayer treated in the Se-atmosphere. This Se-atmosphere treatment may convert the ZnSe/GaAs:Se epilayer into the p-type. The SA peak was found to be related to a complex donor like a $(V_{Se}-V_{Zn})-V_{Zn}$.

• Korean Journal of Head & Neck Oncology
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• v.17 no.2
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• pp.216-220
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• 2001

There are many approaches in surgery of posterior hypopharyngeal wall cancer according to location, extent, and invasion depth of primary cancer. And many reconstruction methods have been used in reconstruction of surgical defect remaining after wide resection of primary cancer. Posterior hypopharyngeal wall cancer is relatively rare, so its surgical experiences are fewer than those of pyriform sinus cancer and there have been few reports of surgical approaches and reconstruction methods of posterior hypopharyngeal wall cancer. Recently, we experienced a case of posterior hypopharyngeal wall cancer reconstructed with longus colli flap and skin graft after failure of radial forearm free flap in a 72-year -old man and report it with the review of the literatures.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.11a
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• pp.98-99
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• 2008

To obtain the single crystal thin films, $AgGaSe_2$ mixed crystal was deposited on thoroughly etched semi-insulating GaAs(100) substrate by the hot wall epitaxy (HWE) system. The source and substrate temperatures were $630^{\circ}C$ and $420^{\circ}C$, respectively. The temperature dependence of the energy band gap of the $AgGaSe_2$ obtained from the absorption spectra was well described by the Varshni's relation, $E_g$(T) 1.9501 eV - ($8.79\times10^{-4}$ eV/K)$T^2$/(T + 250 K). After the as-grown $AgGaSe_2$ single crystal thin films was annealed in Ag-, Se-, and Ga-atmospheres, the origin of point defects of $AgGaSe_2$ single crystal thin films has been investigated by the photoluminescence(PL) at 10K. The native defects of $V_{Ag}$, $V_{Se}$, $Ag_{int}$, and $Se_{int}$ obtained by PL measurements were classified as a donors or acceptors type. And we concluded that the heat-treatment in the Ag-atmosphere converted $AgGaSe_2$ single crystal thin films to an optical p-type. Also, we confirmed that Ga in $AgGaSe_2$/GaAs did not form the native defects because Ga in $AgGaSe_2$ single crystal thin films existed in the form of stable bonds.

• Archives of Craniofacial Surgery
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• v.11 no.1
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• pp.13-18
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• 2010

Purpose: Nasal defect can be caused by excision of tumor, trauma, inflammation from foreign body reaction. Nose is located in the middle of face and protruded, reconstruction should be done in harmony with size, shape, color, and textures. We report various methods of nasal reconstruction using local flaps. Methods: From March 1998 to July 2008, 36 patients were operated to reconstruct the nasal defects. Causes of the nasal defects were tumor (18 cases), trauma (11 cases), inflammation from foreign body reaction (5 cases) and congenital malformation (2 cases). The sites of the defects were ala (22 cases), nasal tip (8 cases) and dorsum (6 cases). The thickness of the defects was skin only (5 cases), dermis and cartilagenous layer (7 cases) and full-thickness (24 cases). According to the sites and thickness of the defects, various local flaps were used. Most of alar defects were covered by nasolabial flaps or bilobed flaps and the majority of dorsal and tip defects were covered by paramedian forehead flaps. Small defects below $0.25 cm^2$ were covered with composite graft or full-thickness skin graft. Results: The follow-up period was 14 months. Partial flap necrosis was observed in a case, and one case of infection was reported, it was improved by wound revision and antibiotics. Nasal reconstruction with various local flaps could provide satisfactory results in terms of color and texture match. Conclusion: The important factors of nasal reconstruction are the shape of reconstructed nose, color, and texture. Nasolabial flap is appropriate method for alar or columellar reconstruction and nasolabial island flap is suitable for tip defect. The defect located lateral wall could be reconstructed with bilobed flap for natural color and texture. Skin graft should be considered when the defect could not afford to be covered by adjacent local flap. And entire nasal defect or large defect could be reconstructed by paramedian forehead flap.

• Journal of Periodontal and Implant Science
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• v.27 no.4
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• pp.767-783
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• 1997

Guided tissue regeneration, bone graft procedures, and application of growth factors have been used to regenerate lost periodontal tissues. Recently, enamel matrix derivative has been introduced into periodontal regeneration procedures in expectation of promoting new bone and cementum formation. The purpose' of this study was to evaluate the effect of enamel matrix derivative in 1-wall intrabony defects in beagle dogs. For this purpose, each dog was anesthesized using intravenous anesthesia and mandibular 1st, 3rd premolars were extracted. 2 months later, the 1-wall intrabony defects(mesio-distal width: 4mm, depth: 4mm) were created on the distal side of 2nd premolars and mesial side of 4th premolars. The control group was treated with debridement alone, and experimental group was treated with debridement and enamel matrix derivative application. The healing processes were histologically and histometrically observed after 8 weeks and the results were as follows : 1. The length of junctional epithelium was $0.94{\pm}0.80mm$ in the control group, $0.57{\pm}0.42mm$ in the experimental group, with no statistically significant difference between groups. 2. The connective tissue attachment was $1.36{\pm}0.98mm$ in the control group. $0.38{\pm}0.43mm$ in the experimental group, with statistically significant difference between groups(P<0.05). 3. The new cementum formation was $2.49{\pm}1.06mm$ in the control group, $3.59{\pm}0.74mm$ in the experimental group. with statistically significant difference between groups(P<0.05). 4. The new bone formation was $1.92{\pm}0.97mm$ in the control group, $2.32{\pm}0.59mm$ in the experimental group. with no statistically significant difference between groups. Within the limitation to this study protocol, enamel matrix derivative application in 1-wall intrabony defect enhanced new cementum formation. Although there was no statistically significant difference, enamel matrix derivative also seems to be effective in inhibition of apical migration of junctional epithelium and new bone formation.

• Journal of Periodontal and Implant Science
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• v.37 no.3
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• pp.465-478
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• 2007

Various periodontal barrier membranes used in many clinical and experimental fields, and many recent studies of membranes have reported good results. To improve clinical results, selection of barrier membranes is an important factor. So, we need not only to evaluate various barrier mem-branes, but also to understand the property of barrier membranes appropriate to defect characteristics. For this purpose, this study reviewed available literature, evaluated comparable experimental models, and compared various barrier membranes. From above mentioned methods, the following conclusions are deduced. 1. In i-wall periodontal defect models, new bone formation showed a consistent result, almost 30% of the defect size. New cementum formations measured mostly 40% of the defect size, but showed more variations than new bone formations. This seems to be resulted form difference in experimental methods, so standardization in experimental methods is needed for future studies. 2. Application PLGA barrier membrane to periodontal defect demonstrated improved healing in new bone and new cementum. 3. There was a minimal periodontal regeneration with calcium sulfate barrier membrane only. But, there was better healing pattern in combination of calcium sulfate membrane with bone graft material, such as DFDBA, 4. There was no significant difference between the experimental group that used chitosan mem-brane only and the control group. But, in combination with bone graft material for space maintanence, periodontal regeneration was improved. Overall, Space maintenance is a critical factor for Guided tissue regeneration using barrier membranes. Also, a barrier membrane itself that has difficulty in maintaining space, achieved better result when used with graft material.

• Journal of Chest Surgery
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• v.28 no.4
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• pp.412-415
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• 1995

Primary cardiac tumors are extremely rare and about 20-25% of primary cardiac tumors are malignant. Recently we have experienced a case of primary cardiac rhabdomyosarcoma originated on the right atrial wall. Patient was 41 years-old women and chief complaints were pitting edema and exertional dyspnea. Emergency operation was performed to relieve symptoms by pericardial effusion that hac been seen on the echocardiogram and large soft mass in right atrial cavity on the MRI. About 700ml amounts of bloody pericardial effusion was collected into the pericardial cavity. 4X5X5 cm sized ingrowing soft mass in the right atrial cavity and two small sized outgrowing masses were inspected. A tumor was invaded into the SA node and superior limbic portion of fossa ovalis. And then mass & right atrial free wall was resected but areas of SA node and fossa ovalis were not resected. Defect of right atrial wall was reconstruced with bovine patch. She was discharged after 2 weeks without any problems and she has been treated with chemotherapy.

• Proceedings of the IEEK Conference
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• 1999.11a
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• pp.913-916
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• 1999

Recent developments of carbon nanotubes are reviewed［1,2,3,4］. We use Tersoff carbon potential for bonded interactions［5］ and Lennard-Jones 12-6 potential for non bonding interactions［6］to describe mechanical properties of the temperature-dependent armchair single wall carbon nanotube. At first we report that through defect number and bonding energy calculation, how single wall carbon nanutube is capped in the constant temperature. (300K, 2000K, 3000K, 4000K) At second, we perform MD simulation, which are performed on the energy optimized structure of carbon nanotube.