• Korean Journal of Head & Neck Oncology
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• v.1 no.1
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• pp.63-74
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• 1985

Although regional and myocutaneous flaps are still the standard in head and neck reconstruction. The capacity to transfer distant tissues by microsurgical technique expands the reconstructive surgeon's ability to restore severe deformities of the head and neck. From 1981 to 1985, thirteen patients with extensive defects of the head and neck after extirpative surgery of tumor have been reconstructed utilizing the technique of microsurgical composite tissue transplantation. In this series of patients, six presented with reconstructions in the different region of the head and neck with review of literatures. The results of case analysis are summarized as follows: 1) Transplantation was successful in twelve among thirteen patients (92%). 2) Seven patients presented with malignancy and six with benign tumor. 3) Frequent sites of reconstruction were face and mandible. 4) Fourteen free composite tissue transplantations for reconstruction of thirteen patients were obtained six different tissue compositions from eight different donor sites. 5) The recipient artery and vein was most often superficial temporal or facial vessels. 6) The average time of operation was ten hours.

• The Journal of the Korean dental association
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• v.42 no.8 s.423
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• pp.514-522
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• 2004

Clinicians often meet the growing patient who is not treated with fixed prosthesis until alveolar bone growth is completed. When both esthetic and function needs are important, and if proper donor tooth is present, the application of autotransplantation may be better treatment option than space maintainer. Although prognosis of autotransplantation is not always favorable, it depends on the treatment design which is based on the ability of case selection and consideration. This report will present the clinical cases of autotransplantation in growing patient, and discuss about several clinical aspects of autotransplantation.

• Bulletin of the Korean Chemical Society
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• v.30 no.12
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• pp.2927-2929
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• 2009

The hydricities of d$^6$ metal hydride complexes in aqueous solution were calculated by using density functional theoretical (DFT) calculations coupled with a Poisson-Boltzmann (PB) solvent model. Hydricity describes the hydride donor ability of the metal-hydrogen bond, which assists in the study of the mechanism of many catalytic processes and chemical reactions that involve transition metal hydrides. The calculation scheme produced hydricity values that were in good agreement with experimental estimation. The inclusion of a water molecule as a weakly bound ligand to five-coordinate metal complexes gave an improved correlation result.

• Journal of Photoscience
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• v.6 no.3
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• pp.117-121
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• 1999

Photoinduced electron transfer of C60 has been studied by the laser photolysis measuring the transient absorption bands in near-IR region. The electron transfer aromatic amines via the triplet state of C60 is confirmed by the decay of the transient absorption bands of the triplet state of C60 and the rise of the anion radical of C60 and the cation radicals of amines. The rate and efficiency of electron transfer are strongly affected by the donor ability of amines and polarity of solvents. Back electron-transfer kinetics is also strongly affected by the solvent polarity.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2018.05a
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• pp.183-183
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• 2018

In this study, 5-bromo-2,9-bis(5,6-diphenyl-1,2,4-triazin-3-yl)-1,10-phenanthroline (5-bromo-Ph4-BTPhen) was synthesized and evaluated for its ability to remove major radionuclides ($Cs^+$, $Sr^{2+}$, and $Co^{2+}$). The synthesized ligand removed both $Sr^{2+}$ and $Co^{2+}$ from $1mg\;L^{-1}$ aqueous solutions with extraction efficiencies of up to 99% at neutral and alkaline pH. The $Sr^{2+}$ and $Co^{2+}$ removal efficiencies decreased as a consequence of the higher bonding strengths of competing metal ions to the N-donor atoms in the cavity of the ligand; competing divalent ions affected the $Sr^{2+}$ and $Co^{2+}$ removal efficiencies more than monovalent ions.

• Bulletin of the Korean Chemical Society
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• v.34 no.3
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• pp.725-730
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• 2013

An investigation of the coordination behavior of sulfur-containing mixed-donor tribenzo-macrocycles $L^1-L^3$ ($L^1$: 20-membered $O_3S_2$, $L^2$: 20-membered $O_2S_3$, and $L^3$: 23-membered $O_4S_2$) with $d^{10}$-metal ($Ag^+$, $Hg^{2+}$, and $Pb^{2+}$) salts is reported. The X-ray structures of five complexes (1-5) with different structural types and stoichiometries, including mono- to dinuclear species have been determined. Reactions of $L^2$ and $L^3$ with the silver(I) salts ($PF_6{^-}$ and $SCN^-$) afforded two dinuclear 2:2 (metal-to-ligand) complexes with different arrangements: a sandwich-type cyclic dinuclear complex $[Ag_2(L^2)_2](PF_6)_2{\cdot}3CH_2Cl_2$ (1) and a linear dinuclear complex $[Ag_2(L^3)_2(SCN)_2]$ (2), in which two monosilver(I) complex units are linked by an Ag-Ag contact. Reactions of $L^1$ and $L^2$ with mercury(II) salts ($SCN^-$ and $Cl^-$) gave a mononuclear 1:1 complexes $[Hg(L^1)(SCN)_2]$ (3) and $[Hg(L^2)Cl_2]$ (4) with anion coordination in both cases. $L^2$ reacts with lead(II) perchlorate to yield a mononuclear sandwich-type complex $[Pb(L^2)_2(ClO_4)_2]$ (5), giving an overall metal coordination geometry of eight with a square antiprism arrangement. From these results, the effects of the donor variation and the anioncoordination ability on the resulting topologies of the soft metal complexes are discussed.

• Archives of Craniofacial Surgery
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• v.15 no.2
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• pp.70-74
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• 2014

Background: Many options are available to cover a palatal defect, including local or free flaps. The objective of this study was to evaluate the usefulness of palatal mucoperiosteal island flap in covering a palatal defect after tumor excision. Methods: Between October 2006 and July 2013, we identified 19 patients who underwent palatal reconstruction using a palatal mucoperiosteal island flap after tumor excision. All cases were retrospectively analyzed by defect location, size, tumor pathology, type of reconstruction, and functional outcomes. Speech and swallowing functions were evaluated using a 7-point visual analog scale (VAS) score. Results: Among the 19 patients, there were 7 men and 12 women with an age range of 25 to 74 years (mean, $52.5{\pm}14.3$ years). The size of flaps was $2-16cm^2$ (mean, $9.4{\pm}4.2cm^2$). Either unilateral or bilateral palatal island flaps were used depending on the size of defect. During the follow-up period (mean, $32.7{\pm}21.4$ months), four patients developed a temporary oronasal fistula, which healed without subsequent operative. The donor sites were well re-epithelized. Speech and swallowing function scores were $6.63{\pm}0.5$ and $6.58{\pm}0.69$ on the 7-point VAS, indicating the ability to eat solid foods and communicate verbally without significant disability. Conclusion: The palatal mucoperiosteal island flap is a good reconstruction modality for palatal defects if used under appropriate indications. The complication rates and donor site morbidity are low, with good functional outcomes.

• Journal of the Korean Chemical Society
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• v.36 no.6
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• pp.802-811
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• 1992

The conformations of several carbene-olefin-transition metal complexes[$(CO)_4M$-(CHX)olefin] (X: $OCH_3,\;NHCH_3,\;SCH_3$, M: C, Mo, W) have been studied by means of Extend Huckel calculations. In the case of $d^6$ transition metal octahedral complexes, it is shown that the two main factors which determine the optimal conformation are metal-to-ligand back-donation and direct ligand-ligand interaction at the metal, but the ligand-ligand interaction dominates the situation for a metal that is coordinated to $\pi$ acceptor ligands and to $\pi$ donor group on the carbene. The relative amounts of both factors depend strongly on the electronic nature of the ligands at the metal. The greater electron donating ability of nitrogen stabilizes amino-substituted carbene complexes compared with their alkoxyl substituted analogues. This interaction is optimal when the $\pi$ systems of the carbene and olefin are coplanar. The introduction of the $\pi$ donor group on the carbene carbon increases also the importance of the ligand-ligand interaction.

• Applied Chemistry for Engineering
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• v.34 no.6
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• pp.633-639
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• 2023

We synthesized 2-(10-methyl-10H-phenothiazin-3-yl)-5-phenyl-1,3,4-oxadiazole (MPPO) and 5,5-(10-methyl-10H-phenothiazin-3,7-diyl)-bis-(2-phenyl-1,3,4-oxadiazole) (DPPO). MPPO has both electron-donating and electron-accepting substituents with asymmetric molecular geometry. By incorporating one extra electron-accepting group into MPPO, we created a symmetric molecule, which is DPPO. The optical and electrochemical properties of these compounds were measured. The lowest unoccupied molecular orbital (LUMO) level of DPPO was lower than that of MPPO. The excited-state dipole moment of DPPO, with symmetric geometry, was calculated to be 4.1 Debye, whereas MPPO, with asymmetric geometry, had a value of 7.0 Debye. The charge-carrier mobility of both compounds was similar. We fabricated non-doped organic light-emitting diodes (OLEDs) using D-A type molecules as an emitting layer. The current efficiency of the DPPO-based device was 7.8 cd/A, and the external quantum efficiency was 2.4% at 100 cd/m², demonstrating significantly improved performance compared to the MPPO-based device. The photophysical and electroluminescence (EL) characteristics of the two D-A type molecules showed that molecular symmetry, as well as the lowered LUMO level of DPPO, played critical roles in the enhancement of EL performance.

• Microbiology and Biotechnology Letters
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• v.40 no.2
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• pp.104-110
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• 2012

Glycosynthase is an active site nucleophile mutant enzyme, prepared from glycosidase, which is capable of synthesizing oligosaccharide derivatives without the hydrolysis of the product. Thermoacidophilic ${\alpha}$-glucosidase of Thermoplasma acidophilum (AglA) exhibits a transglycosylating activity yielding various glycosides. AglA was converted to glycosynthase by the substitution of the catalytic nucleophile Asp-408 residue into non-nucleophile glycine in order to increase its ability to synthesize various glycosides by transglycosylation. The glycosynthase mutant was purified by Ni-NTA chromatography and its glycoside-synthesizing activity was measured by using an external nucleophile, sodium formate buffer, providing maltose as a donor and p-nitrophenyl-${\alpha}$-D-glucopyranoside ($pNP{\alpha}G$) as an acceptor, respectively. In addition, $pNP{\alpha}G$ was examined for its feasibility to act as both a donor and an acceptor, and products were compared with those of the wildtype enzyme. The mutant enzyme was found to catalyze the formation of a specific product from $pNP{\alpha}G$ with a yield of 42.5% without further hydrolysis, while the wild-type enzyme produced two $pNP{\alpha}G$ products at low yields. The results demonstrate the possibility of satisfactory yields for the reactions in the presence of small amounts of acceptor, and demonstrate that the high activity of the mutant, at pHs below neutrality, was applicable in the transfer of glucose from the natural donor.