• Journal of Chest Surgery
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• v.37 no.4
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• pp.313-321
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• 2004

Excellent clinical results of the arterial switch operation and the limited availablity of the intraventricular rerouting has recently made an arterial switch operation to become the therapeutic method of choice for the repair of double-outlet right ventricle (DORV) with subpulmonary ventricular septal defect (VSD). The early and midterm outcomes of arterial switch operation for this anomaly were evaluated. Material and Method: Between August 1994 and July 2002, 13 patients underwent an arterial switch operation for the correction of double-outlet right ventricle with subpulmonary VSD at Dong-A university hospital.. The 50% rule was used to define DORV. Median age and mean body weight were 27 days (range, 3-120 days) and 3.8$\pm$0.7kg (range, 2.92-5.3kg) respectively. Aortic arch anomalies were associated in 6 cases (46.2%), which were all repaired through one-stage operation. The relationship of the great arteries were side-by-side in 8 cases (61.5%) and anteroposterior in 5 (38.5%). Coronary artery patterns were 1 LCx-2R in 6 cases, retropulmonary left coronary artery (LCA) in 6, and intramural LCA in 1 respectively. The enlargement of VSD was required in 1 patient and the patch enlargement of right ventricular outflow tract was performed in another one patient. The Lecompte maneuver was used in all but 3 patients with a side by side relationship of the great arteries. Result: Overall postoperative hospital mortality was 23.1 % (3/13). All operative deaths were occurred in the patients with aortic arch anomalies. There was one late death related to the postoperative complication of the central nerve system during the mean follow-up of 41.3$\pm$30.7 months. Pulmonary valvar stenosis (＞30mmHg of pressure gradient) developed in 1 patient (10%) and left pulmonary artery stenosis in 2 (20%), among them, one required reoperation 52 months after repair. There was an asymptomatic patient with moderate aortic regurgitation. 5-year survival rate including operative deaths was 68.3%. Conclusion: Although the operative mortality is high in the patients with aortic arch anomaly, the arterial switch operation for DORV with supbpulmonary VSD can be performed with low operative mortality and low reoperation rate in the patients Without arch anomaly. The arterial switch operation can be considered a good option for this complex anomaly.

• Progress in Medical Physics
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• v.19 no.1
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• pp.73-79
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• 2008

Retinal prosthesis is regarded as the most feasible method for the blind caused by retinal diseases such as retinitis pigmentosa (RP) or age related macular degeneration (AMD). Recently Korean consortium launched for developing retinal prosthesis. One of the prerequisites for the success of retinal prosthesis is the optimization of the electrical stimuli applied through the prosthesis. Since electrical characteristics of degenerate retina are expected to differ from those of normal retina, we performed voltage stimulation experiment both in normal and degenerate retina to provide a guideline for the optimization of electrical stimulation for the upcoming prosthesis. After isolation of retina, retinal patch was attached with the ganglion cell side facing the surface of microelectrode arrays (MEA). $8{\times}8$ grid layout MEA (electrode diameter: $30{\mu}m$, electrode spacing: $200{\mu}m$, and impedance: $50k{\Omega}$ at 1 kHz) was used to record in-vitro retinal ganglion cell activity. Mono-polar electrical stimulation was applied through one of the 60 MEA channel, and the remaining channels were used for recording. The electrical stimulus was a constant voltage, charge-balanced biphasic, anodic-first square wave pulse without interphase delay, and 50 trains of pulse was applied with a period of 2 sec. Different electrical stimuli were applied. First, pulse amplitude was varied (voltage: $0.5{\sim}3.0V$). Second, pulse duration was varied $(100{\sim}1,200{\mu}s)$. Evoked responses were analyzed by PSTH from averaged data with 50 trials. Charge density was calculated with Ohm's and Coulomb's law. In normal retina, by varying the pulse amplitude from 0.5 to 3V with fixed duration of $500{\mu}s$, the threshold level for reliable ganglion cell response was found at 1.5V. The calculated threshold of charge density was $2.123mC/cm^2$. By varying the pulse duration from 100 to $1,200{\mu}s$ with fixed amplitude of 2V, the threshold level was found at $300{\mu}s$. The calculated threhold of charge density was $1.698mC/cm^2$. Even after the block of ON-pathway with L-(1)-2-amino-4-phosphonobutyric acid (APB), electrical stimulus evoked ganglion cell activities. In this APB-induced degenerate retina, by varying the pulse duration from 100 to $1200{\mu}s$ with fixed voltage of 2 V, the threshold level was found at $300{\mu}s$, which is the same with normal retina. More experiment with APB-induced degenerate retina is needed to make a clear comparison of threshold of charge density between normal and degenerate retina.

• Progress in Medical Physics
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• v.19 no.3
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• pp.157-163
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• 2008

Retinal prosthesis is regarded as the most feasible method for the blind caused by retinal diseases such as retinitis pigmentosa or age-related macular degeneration. One of the prerequisites for the success of retinal prosthesis is the optimization of the electrical stimuli applied through the prosthesis. Since electrical characteristics of degenerate retina are expected to differ from those of normal retina, we investigated differences of the retinal waveforms in normal and degenerate retina to provide a guideline for the optimization of electrical stimulation for the upcoming prosthesis. After isolation of retina, retinal patch was attached with the ganglion cell side facing the surface of microelectrode arrays (MEA). $8{\times}8$ grid layout MEA (electrode diameter: $30{\mu}m$, electrode spacing: $200{\mu}m$, and impedance: 50 $k{\Omega}$ at 1 kHz) was used to record in-vitro retinal ganglion cell activity. In normal mice (C57BL/6J strain) of postnatal day 28, only short duration (<2 ms) retinal spikes were recorded. In rd/rd mice (C3H/HeJ strain), besides normal spikes, waveform with longer duration (~100 ms), the slow wave component was recorded. We attempted to understand the mechanism of this slow wave component in degenerate retina using various synaptic blockers. We suggest that stronger glutamatergic input from bipolar cell to the ganglion cell in rd/rd mouse than normal mouse contributes the most to this slow wave component. Out of many degenerative changes, we favor elimination of the inhibitory horizontal input to bipolar cells as a main contributor for a relatively stronger input from bipolar cell to ganglion cell in rd/rd mouse.

• Journal of Chest Surgery
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• v.29 no.10
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• pp.1081-1089
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• 1996

Pulmonary atresia with intact ventricular septum has continued to have a high surgical mortality and morbidity. This mAy attribute to the non-uniformity of the anomaly. We reviewed a total of 34 infants with pulmonary atresla and intact ventricular septum managed in this hospital between 1987 and 1995. Mean age and body weight were 57.2 (range, 3-208) days and 4.1 (range, B.3∼6.8) kg. The preoperative Z-value of the diameter of the tricuspid valve was less than -2 in 85.2% of patients and less than -4 in 33. 3% . It is well correlated w th right ventricular cavity size (n=27. r10.68, p< 0.05). Coronary artery-right ventricular fistulas were identified in 3 patients, and right ventricular dependency was suspected in 1 Over All hospital mortality was 23.5%(8/34), although it decreased to 16.6%(4124) in 1990s. Subsequent procedures were performed in 6 patients between 3 days and 58 months after Initial palliation : one bidirectional cavopulmonary shunt and 1 Fontan operation after systemic-pulmonary shunt, 3 transannular patch + atrial septal defect closure and 1 additional systemic-pulmonary shunt after polmonary valvectomy or valvotomy. Changes of Z-values of the diameter of tricuspid valve have been followed up in 11 patients between 1 and 66 months postoperatively. Z-values were increased In 5 out of 8 transannular right ventriculAr outflow tract enlargement group and in 1 out of 3 pulmonary valvectomy or valvotomy group. Our data suggest that tailoring a treatment to right ventricular cavity size and coronary anom lies may improve the surgical outcome. A Z-value of the tricuspid valve diameter could be used.

• Journal of the Korean Institute of Landscape Architecture
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• v.36 no.2
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• pp.60-68
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• 2008

Three land-use limitations including water hazard, soil erosion and fallow potential were evaluated to define an unfair area. Landscape indices in the unfair areas, defined by evaluations before and after landscape enhancement, were computed by Fragstats v3.3 and compared in order to propose a landscape enhancement plan. The results are as follows: First, as a result of the land evaluation, 388.56ha was analyzed for the 1st class(S1), 623.25ha for the 2nd class(S2), 138.08ha(S3s: 82.47ha, S3e: 51.88ha) for the 3rd class(S3), 230.44ha(N1w: 194.91ha, N1e: 23.09ha, N1es: 13.94ha) for the 4th class(N1), and 67.91ha(N2w: 60. 89ha, N2es: 7.02ha) for the 5th class(N2). The classes under the 3rd class(including the 3rd class) were determined as an unfair area, and proposed landscape enhancement for them. Second, it was proposed that unfair areas with potential water hazards(N1 w, N2w) be restored as a wetland and buffer zone. At this point, the farmers owning these fields could be compensated using the direct payment for landscape conservation(DPLC). Areas witha relatively lower slope(S3e) or a steep slope(N1e) containing soil erodibility potential were proposed to be restored as a sod-culture-applied field and substitute vegetation or potentially natural vegetation, respectively. The unfair areas having fallow potential(S3s, N1es, N2es) were proposed to apply special use crops for the S3s fields, native plants for the N1es fields, and intended fallow for the N2es fields. Third, after landscape enhancement, theforest had higher values in the indices of NP, PLAND, LSI, IJI, and TCA, while paddy and upland had lower values in most indices except NP and LSI. The forest patches increased and were more plentiful with their restoration and had much greater possibility to join with nearby patches. With continued restoration, forest patches will have a large core area and small number of patches due to the conglomeration of patches, which positively influences the species of diversity in the forest patches.

• Journal of the Korean earth science society
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• v.18 no.6
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• pp.500-514
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• 1997

With respect to the amphibolites in the Mungyong area of the central part of the Ogcheon Fold Belt, detail field occurrence, texture and geochemical properties within each sills and petrogenetic environment are presented. We confirmed that the amphibolites in the Sangnaeri Formation (Ogcheon Supergroup) and limestone(Cambro-Ordovician Chosun Supergroup) sequences are metamorphosed dolerite sills which are roughly concordant to bedding of country rocks. Geologic distribution of the rocks is distinctly improved compared with those of previous investigations. There are four main sills so far observed in the study area. One is emplaced in limestone(Ls Sill, about 3 m thick) and the others are emplaced in Sangnaeri Formation, which are named First Sill(about 40 m thick), Second Sill(about 100 m thick) and Third Sill(about 40 m thick) from lower to upper horizons of the meta-pelitic sequences. The thick sills are intruded by minor sills and the Third Sill is a composite sill consisting of two main and two minor sills. Each sill has fine grained chilled marginal zones and grain size increases inwards from both contacts. The Second Sill has various vein and white patch in central part and the rock compositions vary systematically from margin to central part. $SiO_2,\;Na_2O,\;K_2O\;and\;P_2O_5$ increase, whereas $TiO_2,\;FeO,\;Al_2O_3\;and\;CaO$ decrease toward the contort. We investigate the major and trace element variations of ten selected rock compositions as intruding initial magma take occurrence and chemical properties into consideration. The compositional variations of them can not be explained by fractionation crystallization of single magma. Geologic distribution, geochemical properties and previous data suggest that amphibolite precursors(basaltic magma) of the study area were intrusive as sill-like in an intracontinental rift environment.

• Journal of Korean Society of Forest Science
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• v.89 no.5
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• pp.645-654
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• 2000

The aim of this study was to described the genetic structure of Eleutherococcus senticosus in Korea. We investigated 10 patches, which are eight Korean patches and two foreign patches come from Russia and China growing at Korean habitat, using ISSR(inter-simple sequence repeats) markers. In ISSR PCR, the overall percentage of polymorphic ISSR amplicons was 76% and the mean number of amplicons per ISSR primer was 11.5, which were higher than the RAPD results for the some cultivars collected in Korea(Kim et al., 1998) ; 57% and 5.7, respectively. So ISSR markers provide more powerful tool than RAPD markers for the investigation of genetic variation in E. senticosus. There are relatively high genetic variation among patches as 62.8%, but low variation within eight Korean patches. Such pattern of genetic variation, which is not ordinary in other tree species, may be result from the narrow and limited habitats and the asexual reproduction of this species at the natural stands in Korea. Although the small sample size in this study seemed to be resulted in the high genetic variation among patches, the overall genetic interpretation of this study might not be much affected on the basis of the characteristics of the distribution and the reproduction system of E. senticosus. Analysis of genetic distance between all pairs of the patches did not reveal any trends with regard to geographic distance, which was confirmed by the results obtained from AMOVA(analysis of molecular variance) and PCA(principal component analysis). These results suggest that, in addition to the preservation of the natural stands, the conservation of larger number of patches with small number of individuals per patch is more effective for the ex situ conservation and for maintaining the genetic diversity of E. senticosus in Korea than smaller patches with large number of individuals.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.25 no.3
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• pp.55-66
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• 2020

Near-inertial waves (NIW) which are primarily generated by wind can contribute to vertical mixing in the ocean. The energetic NIW can be generated by typhoon due to its strong wind and preferable wind direction changes especially on the right-hand side of the typhoon. Here we investigate the generation and distribution of NIW using the output of a real-time ocean forecasting system. Five-year model outputs during 2013-2017 are analyzed with a focus on cases of energetic NIW generation by the passage of three typhoons (Halong, Goni, and Chaba) over the East Sea. Calculations of wind energy input (${\bar{W}}_I$), and horizontal kinetic energy in the mixed layer (${\bar{HKE}}_{MLD}$) reveal that the spatial distribution of ${\bar{HKE}}_{MLD}$, which is strengthened at the right-hand side of typhoon tracks, is closely related with ${\bar{W}}_I$. Horizontal kinetic energy in the deep layer (${\bar{HKE}}_{DEEP}$) shows patch-shaped distribution mainly located at the southern side of the East Sea. Spatial distribution of ${\bar{HKE}}_{DEEP}$ shows a close relationship with negative relative vorticity regions caused by warm eddies in the upper layer. Monthly-mean ${\bar{HKE}}_{MLD}$ and ${\bar{HKE}}_{DEEP}$ during a typhoon passing over the East Sea shows about 2.5-5.7 times and 1.2-1.6 times larger values than those during summer with no typhoons, respectively. In addition, their magnitudes are respectively about 0.4-1.0 and 0.8-1.0 times from those during winter, suggesting that the typhoon-induced NIW can provide a significant energy to enhance vertical mixing at both the mixed and deep layers during summer.

• Korean Journal of Remote Sensing
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• v.36 no.2_2
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• pp.249-261
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• 2020

Coastal monitoring using multiple platforms/sensors is a very important tools for accurately understanding the changes in offshore marine environment and disaster with high temporal and spatial resolutions. However, integrated observation studies using multiple platforms and sensors are insufficient, and none of them have been evaluated for efficiency and limitation of convergence. In this study, we aimed to suggest an integrated observation method with multi-remote sensing platform and sensors, and to diagnose the utility and limitation. Integrated in situ surveys were conducted using Rhodamine WT fluorescent dye to simulate various marine disasters. In September 2019, the distribution and movement of RWT dye patches were detected using satellite (Kompsat-2/3/3A, Landsat-8 OLI, Sentinel-3 OLCI and GOCI), unmanned aircraft (Mavic 2 pro and Inspire 2), and manned aircraft platforms after injecting fluorescent dye into the waters of the South Sea-Yeosu Sea. The initial patch size of the RWT dye was 2,600 ㎡ and spread to 62,000 ㎡ about 138 minutes later. The RWT patches gradually moved southwestward from the point where they were first released,similar to the pattern of tidal current flowing southwest as the tides gradually decreased. Unmanned Aerial Vehicles (UAVs) image showed highest resolution in terms of spatial and time resolution, but the coverage area was the narrowest. In the case of satellite images, the coverage area was wide, but there were some limitations compared to other platforms in terms of operability due to the long cycle of revisiting. For Sentinel-3 OLCI and GOCI, the spectral resolution and signal-to-noise ratio (SNR) were the highest, but small fluorescent dye detection was limited in terms of spatial resolution. In the case of hyperspectral sensor mounted on manned aircraft, the spectral resolution was the highest, but this was also somewhat limited in terms of operability. From this simulation approach, multi-platform integrated observation was able to confirm that time,space and spectral resolution could be significantly improved. In the future, if this study results are linked to coastal numerical models, it will be possible to predict the transport and diffusion of contaminants, and it is expected that it can contribute to improving model accuracy by using them as input and verification data of the numerical models.

• Journal of Chest Surgery
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• v.34 no.7
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• pp.561-565
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• 2001

Patients who have complex endocarditis with involvement of both the aortic and mitral valves and intervalvular fibrous skeleton are among the most difficult to treat and still have the highest surgical mortality and morbidity rates. We report one case of aortic and mitral valve replacement with reconstruction of the fibrous skeleton performed in a 55-year-old female patient who had an aortic annular abscess and both the aortic and mitral prosthetic valve endocarditis with destruction of the fibrous skeleton. Previously, she had undergone redo double valve replacement\`, Transesophageal echocardiogram showed the paravalvular defect at the noncoronary aortic sinus and abnormal sinus tract along the fibrous skeleton. Emergent operation was performed due to positive blood cultures of staphylococcus epidermidis and persistent sepsis despite appropriate antibiotic therapy. After aortotomy extended to the roof of left atrium, both prosthetic valves and destroyed fibrous skeleton were completely resected and the aortic annular abscess was debrided and closed with a bovine pericardial patch. Reconstructions of both aortic and mitral annuli and the fibrous skeleton were done by using two separate bovine pericardial patches in triangular shape and mechanical valves were implanted. Postoperatively, adequate antibiotic therapies were continued and the patient was discharged at the postoperative 72 days without evidence of recurrence of endocarditis. Transthoracic echocardiogram of the postoperative 8 months shows no paravalvular leakage or recurrence of endocarditis and the patient has been followed up with no symptom.