• International Journal of Vascular Biomedical Engineering
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• v.1 no.2
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• pp.20-29
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• 2003

A new treatment for coronary artery occlusive disease is being developed in which a shunt or conduit is placed directly connecting the left ventricle with the diseased artery at a point distal to the obstruction. To aid in assessing and optimizing its benefit, a computational model of the cardiovascular system was developed and used to explore various design conditions. Simulation results indicate that in complete LAD occlusion, flow can be returned to approximately 65% of normal if the conduit resistance is equal for forward and reverse flow, increasing to 80% in the limit in which backflow resistance is infinite. Increases in flow rate produced by asymmetric flow resistance are considerably enhanced in the case of a partial LAD obstruction since the primary effect of resistance asymmetry is to prevent leakage back into the ventricle("steal") during diastole. Increased arterial compliance has little effect on net flow with a symmetric shunt, but leads to considerable augmentation when the resistance is asymmetric. These results suggest that an LV-LAD conduit will be beneficial when stenosis resistance(Rst) > 27 PRU if resistance is symmetric.

• Radiation Oncology Journal
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• v.33 no.3
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• pp.242-249
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• 2015

Purpose: The purpose of this study is to compare the dosimetry of electron beam (EB) plans and three-dimensional helical tomotherapy (3DHT) plans for the patients with left-sided breast cancer, who underwent breast conserving surgery. Materials and Methods: We selected total of 15 patients based on the location of tumor, as following subsite: subareolar, upper outer, upper inner, lower lateral, and lower medial quadrants. The clinical target volume (CTV) was defined as the area of architectural distortion surrounded by surgical clip plus 1 cm margin. The conformity index (CI), homogeneity index (HI), quality of coverage (QC) and dose-volume parameters for the CTV, and organ at risk (OAR) were calculated. The following treatment techniques were assessed: single conformal EB plans; 3DHT plans with directional block of left anterior descending artery (LAD); and 3DHT plans with complete block of LAD. Results: 3DHT plans, regardless of type of LAD block, showed significantly better CI, HI, and QC for the CTVs, compared with the EB plans. However, 3DHT plans showed increase in the $V_{1Gy}$ at skin, left lung, and left breast. In terms of LAD, 3DHT plans with complete block of LAD showed extremely low dose, while dose increase in other OARs were observed, when compared with other plans. EB plans showed the worst conformity at upper outer quadrants of tumor bed site. Conclusion: 3DHT plans offer more favorable dose distributions to LAD, as well as improved target coverage in comparison with EB plans.

• Korean Journal of Agricultural and Forest Meteorology
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• v.8 no.3
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• pp.183-189
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• 2006

Six japonica and three Tongil type cultivars that were released in different years and planted to a large area during different periods were grown at the experimental farm of Seoul National University in 2001 and compared for traits related to dry matter production and grain yield. The varieties chosen were Jodongji released in 1896, Paldal in 1944, Jinheung in 1962, Nagdong and Tongil (Tonsil type) in 1971, Milyang#23 (Tongil type) in 1976, Hwasung in 1986, Ilpum in 1991, and Dasan (Tonsil type) in 1996. The more recent cultivars tended to have lower canopy light extinction coefficients (K). The K value was 0.601 in the oldest cultivar, Jodongji, and decreased below 0.5 in the cultivars released since 1971. Radiation use efficiency (RUE) was significantly different among cultivars before heading stage, showing no consistent tendency with the year of release and not significantly different after heading. Leaf area duration (LAD) was significantly different among varieties, and LAD values tended to be higher in the more recent cultivars. In particular, this tendency was more obscure in Tongil type cultivars. LAD of whole growth period had a significantly positive correlation with dry matter yield at harvest $(r=0.776^*)$. Dry matters measured at heading and harvest tended to be higher in recently released cultivars, but not significantly. The grain yield of Jodongji was the lowest but there was no significant difference among the other varieties in japonica, while higher yield occurred in the more recent Tongil type. Grain yield was correlated with grain number per square meter, and the more recent Tongil type cultivars had the greater grain number per square meter, In conclusion, not only the dry matter and grain yield but also related traits except K value showed no clear changes when compared with the year of their release in japonica cultivars. However, the increased grain yield in the more recent Tonsil type cultivars might have resulted from the enhanced LAD that lead to the higher dry matter production and in turn to the enlarged sink size.

• Proceedings of the Korea Society of Design Studies Conference
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• 2005.05a
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• pp.280-281
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• 2005

• Korean Circulation Journal
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• v.48 no.11
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• pp.1002-1011
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• 2018

Background and Objectives: The prognostic impact of left axis deviation (LAD) on clinical outcomes in acute heart failure syndrome (AHFS) with left bundle branch block (LBBB) is unknown. The aim of this study was to determine the prognostic significance of axis deviation in acute heart failure patients with LBBB. Methods: Between March 2011 and February 2014, 292 consecutive AHFS patients with LBBB were recruited from 10 tertiary university hospitals. They were divided into groups with no LAD (n=189) or with LAD (n=103) groups according to QRS axis <-30 degree. The primary outcome was all-cause mortality. Results: The median follow-up duration was 24 months. On multivariate analysis, the rate of all-cause death did not significantly differ between the normal axis and LAD groups (39.7% vs. 46.6%, adjusted hazard ratio, 1.01; 95% confidence interval, 0.66, 1.53; p=0.97). However, on the multiple linear regression analysis to evaluate the predictors of the left ventricular ejection fraction (LVEF), presence of LAD significantly predicted a worse LVEF (adjusted beta, -3.25; 95% confidence interval, -5.82, -0.67; p=0.01). Right ventricle (RV) dilatation was defined as at least 2 of 3 electrocardiographic criteria (late R in lead aVR, low voltages in limb leads, and R/S ratio <1 in lead V5) and was more frequent in the LAD group than in the normal axis group (p<0.001). Conclusions: Among the AHFS with LBBB patients, LAD did not predict mortality, but it could be used as a significant predictor of worse LVEF and RV dilatation (Trial registry at KorAHF registry, ClinicalTrial.gov, NCT01389843).

• Journal of Yeungnam Medical Science
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• v.31 no.1
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• pp.13-16
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• 2014

Congenital abnormalities of the coronary arteries are found in 0.6% to 1.3% of patients in coronary angiography. Dual left anterior descending coronary artery (LAD) is a rare coronary anomaly and is incidentally detected during coronary angiography. We report a case of a 65-year-old female with a rare coronary anomaly who was diagnosed with dual LAD via coronary computed tomography and coronary angiography. The imaging studies revealed dual LAD originating from the left main stem and right coronary sinus. These angiographic findings were considered to be consistent with the type IV variety of dual LAD by Spindola-Franco classification. Recognition of dual LAD is important to prevent errors of interpretation of the coronary angiogram and for optimal surgery.

• Journal of the Korean Society of Radiology
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• v.85 no.2
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• pp.428-433
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• 2024

Dual left anterior descending artery (LAD) is a rare congenital coronary artery anomaly with a prevalence of approximately 1% in the general population. To date, 10 types of dual LAD artery anomalies have been reported. Among these, type 4 is one of the rarest. Knowledge and recognition of the dual LAD artery are important for correct diagnosis and planning of coronary bypass surgery and percutaneous coronary intervention. We report a case of a 59-year-old male with type 4 dual LAD artery who presented with dyspepsia and sweating for several months and had approximately 50%-70% stenosis in a major diagonal branch off the short LAD artery.

• Analytical Science and Technology
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• v.5 no.2
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• pp.217-222
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• 1992

An attempt was made to analyze green microstructure of AIN samples prepared by slip casting and dry pressing through Hg-porosimetry. Slip cast samples with narrow pore size distribation and high packing density showed higher sinterability and homogeneous distribution of second phase(s). Hg-porosimetry is and effective way to determine pore structure if "ink bottle" phenomenon does not occur. A comparison study with porosity measurement by quantitative microscopy showed that the effectiveness of Hg-porosimetry measurement could be extended to higher sintered density as long as pores remained open.

• Communications for Statistical Applications and Methods
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• v.30 no.2
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• pp.135-147
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• 2023

Skipped median is more robust than median when outliers are not symmetrically distributed. In this work, we propose a novel algorithm to estimate the skipped median. The idea of skipped median and the new algorithm are extended to regression problem, which is called least clipped absolute deviation (LCAD). Since our proposed algorithm for nonconvex LCAD optimization makes use of convex least absolute deviation (LAD) procedure as a subroutine, regularizations developed for LAD can be directly applied, without modification, to LCAD as well. Numerical studies demonstrate that skipped median and LCAD are useful and outperform their counterparts, median and LAD, when outliers intervene asymmetrically. Some extensions of the idea for skipped median and LCAD are discussed.

• Journal of Korean Society for Atmospheric Environment
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• v.33 no.3
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• pp.233-240
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• 2017

To distinguish between high particulate matter (HPM) and light Asian dust (LAD) events, aerosol optical properties from GOCI were investigated in Seoul from 2014 to 2016. The poor air quality case caused by fine atmospheric particulate matter (i.e., 80<$PM_{10}$<$400{\mu}g/m^3$) is clearly separated from the case of heavy Asian dust that generally shows the $PM_{10}$ concentration more than $400{\mu}g/m^3$. In this study, we have found eight cases for the poor air quality and divided them into the two events(i.e., HPM and LAD). In case of aerosol optical depth (AOD), there was no big difference between two events. However, Angstrom exponent (AE) for HPM events was greater than 1, while that for LAD events less than 1. As a result of comparing aerosol type, non-absorbing fine mode aerosols were dominant for HPM events, but coarse and absorbing coarse mode aerosols for LAD events. Therefore, AE and aerosol type from GOCI can be used to distinguish between two events effectively.