• Journal of Chest Surgery
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• v.27 no.9
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• pp.752-758
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• 1994

From July 1983 to December 1992, 145 patients with mitral valvular disease underwent open heart surgery at Chonbuk National University Hospital. Of these patients, 89 patients[61.4%] required mitral valve replacement. 56 patients [38.6 %] had mitral valve repair. There were 32 women and 24 men and the mean age was 34.3 years[range 6 years to 62 years].There were 23 cases of pure mitral stenosis, 19 cases of mitral regurgitation and 14 cases of mixedmitral valvular disease. The mean duration of symptom was 4.53 years and mean mitral valvularorifice diameter[in cases of pure stenosis and mixed mitral valvular lesion] was 0.96 cm. According to the NYHA classification, the distribution of patients preoperatively was as follows; class IIa, 15 patients; class lib, 17 patients; class III, 22 patients; class IV, 2 patients. Four patients[7%] had an embolic history preoperatively. 24 patients[ 43 %] were in atrial fibrillation. In cases of pure mitral stenosis, the technique used included open mitral commissurotomy[21atients], open mitral commissurotomy with mitral annuloplasty[2 patients]. In mixed mitral valvular disease, open mitral commissurotomy[ll patients] and open mitral commissurotomy with mitral annuloplasty[l patient] were performed. In cases of mitral regurgitation, mitral annuloplasty[5 patients], mitral valvuloplasty[6 patients], mitral annuloplasty with valvuloplasty [3 patients] and ring annuloplasty [5 patients] were performed.There was one perioperative death related to acute renal failure and sepsis. One late death was occurred related to heart failure after 10 months postoperatively. One patient required reoperation due to restenosis and no embolic episode was occured. After operation, 34 patients were in NYHA functional class I, 20 patients were in class IIa.

• Journal of Chest Surgery
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• v.18 no.2
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• pp.305-313
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• 1985

Surgical therapy for dissection of the aorta has had a high mortality. One contributing factor has been hemorrhage from the prosthesis and the suture lines. Recently, a new method of treatment with an intraluminal graft that requires no end-to-end anastomosis has been developed. Of the four patients with dissecting aneurysm of the aorta treated by inserting sutureless ringed intraluminal graft at the Department of Thoracic and Cardiovascular Surgery, S.N.U.H., three were DeBakey type I [one with associated aortic insufficiency] and the other was DeBakey type III. Suspected etiology of the dissection was Marfan`s syndrome in one and hypertension in the others. Total cardiopulmonary bypass was utilized in repairing dissecting aneurysms of the ascending aorta [type A] and simple aortic crossclamping was used for the patient with dissecting aneurysm of the descending aorta. The basic technique consists of inserting the whole ringed graft into the true lumen of the dissected aorta and circumferentially ligating the aorta against the groove in the rings. The proximal ring of the graft effectively stabilized the flail aortic valve in patient with aortic insufficiency associated with dissection of the ascending aorta. There were no hospital deaths and one patient with type III dissecting aneurysm developed postoperative paraparesis and renal insufficiency which was resolved. Follow-up has been from 1 month to 16 months with no evidence of prosthetic problems, such as erosion, migration, or thrombosis.

• Journal of the Korean Magnetic Resonance Society
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• v.10 no.1
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• pp.115-125
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• 2006

Hippuryl-L-histidyl-L-leucine(HHL) is widely used as a substrate of angiotensin converting enzyme(ACE) cleaving the neurotransmitter angiotensin(I) to the octapeptide angiotensin(II). The structure of the substrate molecules should provide information regarding the geometric requirements of the ACE active site. For the purpose of determination of in vivo reaction, metallo(Cu, Zn)-HHL complexes were synthesized and the degree of complex formation were identified by MALDITOF, ESI mass spectrometric analysis. Tn addition, the pH-dependent species distribution curves were obtained by potentiometric titration. Nitrogen atoms of imidazole ring and oxygen atom of caboxylate groups in the peptide chain were observed to be participated in the metal complex formation. After purification of complexes further structural characterization were made by utilizing UV-Vis, electrochemical methods and NMR. Complete NMR signal assignments were carried out by using 2D-spectrum techniques COSY, TOCSY, NOESY, HETCOR. A complex that two imidazole and carboxylate groups are asymmetrically participating to coordination mode was predicted to the solution-state structure of $Cu(II)-HHL_2$ based on $^{13}C-NMR$ signal assignment and NOE information.

• Journal of Korean Ophthalmic Optics Society
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• v.1 no.1
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• pp.53-56
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• 1996

In testing visual acuity of kindergarten's children, single Landolt's ring in chart projector was used under proper intensity of illumination. According to the result of 218 eyes' test, 0.6 V.A. forms 8.5 % at the age of 3, 0.7 V.A. forms 84.7 % at the age of 4, and 1.0 V.A. forms 6.8 % at the age of 5. However, children's visual acuity has been gradually developed with their growth. None of emmetropia can be found through the test. All of the children have ametropic eyes.

• BMB Reports
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• v.49 no.3
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• pp.191-196
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• 2016

Vascular endothelial growth factor (VEGF) is a key mediator of angiogenesis and critical for normal embryonic development and repair of pathophysiological conditions in adults. Although phospholipase D (PLD) activity has been implicated in angiogenic processes, its role in VEGF signaling during angiogenesis in mammals is unclear. Here, we found that silencing of PLD2 by siRNA blocked VEGF-mediated signaling in immortalized human umbilical vein endothelial cells (iHUVECs). Also, VEGF-induced endothelial cell survival, proliferation, migration, and tube formation were inhibited by PLD2 silencing. Furthermore, while Pld2-knockout mice exhibited normal development, loss of PLD2 inhibited VEGF-mediated ex vivo angiogenesis. These findings suggest that PLD2 functions as a key mediator in the VEGF-mediated angiogenic functions of endothelial cells.

• Journal of the Korean Vacuum Society
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• v.5 no.3
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• pp.245-250
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• 1996

$Y_2O_3$ thin film on si(100) was successfully grown by ionized cluster beam(ICBD) technique at substrate temperature of around $500^{\circ}C$ and pressure of ~$10^{-5}$Torr.To prevent the oxidation of Si substrae, a very thin yttrium layer was deposited on Si before reactive depositing of oxygen and yttrium source. In asdeposited stage, b.c.c and h.c.p strucutres of $Y_2O_3$ were observed from S-ary analysis. From the observation of spots and ring patterns in selected area diffractin(SAD) patterns. crystallane formation and growth could be proceeded during the deposition. $Y_2O_3$/mixed layer/$SiO_2=170\AA/50\AA/10\AA$ structure were verified by high resolution transmition electron imcroscopy(HRTEM) image, and the formation of amorphous layer of SiO2 was discussed . Electricla charateristics of the film were also investigated . In as-deposited Pt/$Y_2O_3$/Si sturcuture, leakage current was less than $10^{-6}$A/$\textrm{cm}^2$ at 7MV/cm strength.

• Transactions of the Korean Society of Automotive Engineers
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• v.6 no.1
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• pp.196-204
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• 1998

For the experimental measurement of instantaneous surface temperature of the piston of the DI mono cylinder diesel engine, the instantaneous temperature proves, data acquisition system, and grass-hopper type linkage system were developed. The instantaneous temperatures on the piston bowl, crown, lands and skirt were measured and analyzed, and the following conclusions were derived ; (i) The crank angle for the maximum instantaneous temperature during one cycle varies and moves back and forth by the measuring positions and engine speeds. (ii) The engine speeds, the positions of the measuring points and the cooling water temperature had an effect on the instantaneous temperature amplitude. (iii) The instantaneous temperature suing phenomena appeared on the temperature profiles of the piston crown, top and second land of ring, but on the temperature profiles of the parts of the third land of the fing and skirt, they didn't appear, (iv) The isothermal lines in the piston were acquired through the operation of the finite elements method using the measured temperatures as the boundary conditions.

• Journal of Powder Materials
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• v.3 no.4
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• pp.227-232
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• 1996

(i) The development of a metallurgical bond during the spray forming of clad products has offered the possibility of manufacturing large rolls, including those used in hot and cold strip mills. Small rolls are already being produced in Japan. (ii) Technical developments, including the use-of-multi-atomizers have resulted in the elimination of porosity from the internal bore of a sprayed tube. Bimetallic tubing can also be manufactured and the installation of a 4.5 ton tube plant in the USA should provide low operation costs. (iii) Spray forming offers a potentially low cost manufacturing route for superalloy ring/casing components in high strength superalloys. (iv) A large pilot plant has been built for the spray forming of ultra-clean superalloys for turbine disc applications. (v) Using twin-atomizing technology, special steel billets have been spray formed up to 400mm diameter with deposition yields in excess of 90%. (vi) Al/Si alloy extrusion billets with excellent dimensional tolerances are being manufactured for large scale automotive applications. Several new aluminum alloys have also been developed, including high strength, low density and low cocfficient of expansion materials. (vii) New copper alloys have been developed and pilot plants are in operation to produce these alloys once markets have become established.

• Analytical Science and Technology
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• v.28 no.5
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• pp.347-352
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• 2015

Chemical properties such as heat of formation and density of methylnitroimidazole derivatives were predicted and analyzed by using density functional theory (DFT). Successive addition of energetic nitro groups into an imidazole ring increases both the heat of formation and the density. Using the chemical property values computed by DFT, explosive performance was analyzed with the Cheetah program, and compared with those of TNT, RDX, and HMX, which are currently used widely in military systems. When both C-J pressure and detonation velocity were used as explosive performance, methyldinitroimidazole derivatives show better performance than TNT, while methyltrinitroimidzole is almost close to RDX. Since methylnitroimidazole derivatives have a good merit, i.e. low melting point for melt loading, they are forecasted to be used widely in various military and civilian application.

• Communications of the Korean Mathematical Society
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• v.22 no.1
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• pp.41-51
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• 2007

Let R be a ring with left identity e and suitably-restricted additive torsion, and Z(R) its center. Let H : $R{\times}R{\times}R{\rightarrow}R$ be a symmetric 3-additive mapping, and let h be the trace of H. In this paper we show that (i) if for each $x{\in}R$, $$n=<<\cdots,\;x>,\;\cdots,x>{\in}Z(R)$$ with $n\geq1$ fixed, then h is commuting on R. Moreover, h is of the form $$h(x)=\lambda_0x^3+\lambda_1(x)x^2+\lambda_2(x)x+\lambda_3(x)\;for\;all\;x{\in}R$$, where $\lambda_0\;{\in}\;Z(R)$, $\lambda_1\;:\;R{\rightarrow}R$ is an additive commuting mapping, $\lambda_2\;:\;R{\rightarrow}R$ is the commuting trace of a bi-additive mapping and the mapping $\lambda_3\;:\;R{\rightarrow}Z(R)$ is the trace of a symmetric 3-additive mapping; (ii) for each $x{\in}R$, either $n=0\;or\;<n,\;x^m>=0$ with $n\geq0,\;m\geq1$ fixed, then h = 0 on R, where denotes the product yx+xy and Z(R) is the center of R. We also present the conditions which implies commutativity in rings with identity as motivated by the above result.