• Journal of Advanced Navigation Technology
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• v.28 no.1
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• pp.129-135
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• 2024

In this paper, an analytical approach for the design and analysis of an aperiodic electromagnetic bandgap (EBG)-based power distribution network (PDN) in high-speed integrated-circuit (IC) packages and printed circuit boards (PCBs) is proposed. Aperiodic EBG is an effective method to solve the noise problem of high-speed IC packages and PCBs. However, its analysis becomes challenging due to increased computation time. To overcome the problem, the proposed analytical method entails deriving impedance parameters for EBG island and the overall PDN, which includes locally placed EBG structures. To validate the proposed method, a test vehicle is fabricated, demonstrating good agreement with the measurements. Significantly, the proposed analytical method reduces computation time by 99.7 %compared to the full-wave simulation method.

• Journal of Chest Surgery
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• v.41 no.2
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• pp.210-215
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• 2008

Background: Drug-eluting stents are contributing to the exponential growth of percutaneous coronary intervention, and even in the patients with left main coronary artery disease, owing to the decreased restenosis rate. Our study aimed at comparing the one-year results after coronary artery bypass grafting versus percutaneous coronary intervention with drug-eluting stents in patients with left main coronary artery disease. Material and Method: Those patients who underwent coronary bypass surgery or stenting at our hospital under the diagnosis of left main coronary artery disease were divided in two groups. The variables for comparison were the preoperative disease severity, the length of the hospital stay, the early mortality and the cumulative incidence of mortality, myocardial infarction and repeated revascularization. Result: There were 101 cases in the surgery group and 78 cases in the stent group. Age, gender, the risk factors, the left ventricular ejection fraction and the proportion of acute coronary syndrome showed no significant differences between the two groups. The surgery group showed a more severe condition according to the Euroscore, a greater incidence of urgency, a longer hospital stay and a greater incidence of multi-vessel disease. The early mortality and one-year cumulative mortality were not different between the groups. The Euroscore-matched comparison for the surgery group (41 patients) and the stent group (78 patients) showed no significant differences in the Euroscore, age, gender, risk factors and the proportion of acute coronary syndrome. The surgery group in the Euroscore-matched comparison showed more multi-vessel disease and a longer hospital stay. The surgery group showed lower early mortality and lower one-year cumulative mortality, but this was statistically insignificant (0% vs 2.6%, respectively, p=0.55; 0% vs 6.6%, respectively, p=0.30). The rates of repeated revascularization and major adverse events (death or myocardial infarct) were lower in the CABG group, but this was not statistically significant (13.3% vs 6.3%, respectively, p=0.48; 10.0% vs 0%, respectively, p=0.09). Conclusion: Percutaneous coronary intervention using drug-eluting stents in low-risk patients with left main coronary artery disease resulted in a shortened length of the hospital stay, as compared with that of the CABG group of patients. However, the patients who underwent percutaneous coronary intervention using drug-eluting stents showed a tendency for an increased rate of repeated revascularization and higher one-year cumulative mortality. Further studies with large populations and longer follow-up will be necessary to reaffirm our findings.

• Journal of Chest Surgery
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• v.35 no.4
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• pp.261-266
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• 2002

In an attempt to avoid the adverse effects of the cardiopulmonary bypass, off pump coronary artery bypass grafting(Off pump CABG) that has recently been rediscovered and refined. We compared the preoperative risk factors and in-hospital outcomes of patients done Off pump with those done On pump CABG. Material na Method: One hundred seventy eight patients was underwent CABG between January 2001 and July 2001 12 patients whom underwent associated valvular or left ventricular volume reduction surgery were excluded in this study Data were collected for 52 Off pump CABG and 114 On pump CABG for patient and disease risk factors, extent of coronary disease, and in-hospital outcomes. Result: Off pump CABG and On pump CABG groups did not show any differences in their patient and disease risk factors, and extent of coronary disease. Off pump CABG group had significantly lower mean operation time(234 $\pm$ 37 min vs 290 $\pm$ 48 min, p<0.001), lower mean CK-MB level(10.1 $\pm$ 13.5 IU/L vs 33.1 $\pm$ 18.2 IU/L, p<0.001) and mean ventilation time(14.8 $\pm$ 3.5 hours vs 16.2 $\pm$ 4.9 hours, p=0.048) than On pump CABG groups. On pump CABG group had significantly more distal grafts(3.4 $\pm$ 0.9 vs 2.6 $\pm$ 0.8, p<0.001) than Off pump CABG groups. There were no operative mortality in two groups. Off pump) CABG and On pump CABG groups did not show any differences in their postoperative complications and outcomes including perioperative myocardial infarction, stroke, respiratory failure, renal failure, reoperation, the amount of bleeding, the need of intraaortic balloon pump, the need of inotropics, and the stay of intensive care unit and hospital. Two patients were converted to On pump CABG. Conclusion: This study showed that patients having Off pump CABG are not exposed to a greater risks of adverse outcomes and also provided evidence that patients having Off pump CABG have significantly lower operation time, CK-MB, ventilation time and less distal grafts. Although there may be potential benefits to Off pump CABG, further studies must be directed to determine those patients who would benefit from Off pump CABG.

• Journal of Chest Surgery
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• v.41 no.6
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• pp.710-717
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• 2008

Background: Atrial fibrillation is associated with several complications such as cerebro-vascular accidents and peripheral arterial embolism. Most of the patients who have this arrhythmia chronically feel their heart beating and so they are frightened; therefore, the quality of a patient's life is decreased. The purpose of this article is to determine the long term results of a modified Maze procedure and the factors that influence the success of the procedure. Material and Method: This study enrolled 88 patients who underwent the modified Maze with using cryoablation between June, 2001 and February, 2007. The 88 consecutive patients were divided into two groups ac cording to how the pulmonary veins were isolated, that is, with or without cryoablation. There were 58 patients who were isolated by cutting and sewing in the right pulmonary veins and by cyroablation in the left pulmonary veins in group 1 (group 1, n=58), and 30 patients who underwent isolation by cryoablation in the right & left pulmonary veins were placed in group 2 (group 2, n=30). The ECG was checked at discharge to determine the sinus conversion rate and we followed up the patients to determine whether or not the patients maintained sinus rhythm. We also checked the ECG at the last visit to determine the patients' heart rhythm. Result: The mean follow up time was $44.3{\pm}19.2$ months. At discharge, 72.4% of the patients in group 1 were in proper sinus rhythm and 66.7% of the patients in group 2 were in proper sinus rhythm. At the last follow up, 81% of the patients in group 1 were in normal sinus rhythm and 60% of the patients in group 2 were in normal sinus rhythm. When we analyzed the data via the Kaplan-Meier method, 86.5% of the patients were free from atrial fibrillation (% free from AF) at 1 year, 80% of the patients were free from atrial fibrillation at 5 year in group 1 and 70% of the patients were free from atrial fibrillation at 1 year and 51 % of the patients in group 2 were free from atrial fibrillation at 5 year. Conclusion: The modified Maze technique using cryoablation was a simple and effective procedure. But the success rate of the Maze technique using cryoblation is lower than that of the standard Maze III. The method using cryoablation shorten the operation time, but we must conduct more studies to get a better result of the modified Maze technique with using cryoablation.

• Journal of Chest Surgery
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• v.35 no.7
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• pp.542-547
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• 2002

Background: Postpneumonectomy empyema(PPE) is an infrequent but potentially life-threatening complication. To date, various surgical efforts have been made to manage this complication. We reviewed our 20-year surgical experience of PPE and long-term follow-up data. Material and Method: Total of 37 patients who were treated for PPE between fan, 1980 and Jun, 2000 were included. Various clinical factors such as micro-organism, operative method and timing, presence of bronchopleural fistula(BPF), underlying disease and fate of empyema cavity were retrospectively reviewed and analyzed. Result: Majority of patients(34) underwent Eloesser operation for effective drainage. There was only one operative mortality. The causative organisms were Staphylococcus species and Pseudomonas species in 46% BPF was found in 20 cases, among which spontaneous closures took place in 4 cases. The chest wall was closed in 40%(8/20) of patients with BPF, compared to 59%(10/17) without BPF. The closure rate was statistically better in patients without BPF(p=0.006). Even though the patients with benign disease showed higher closure rate(50%) than those with lung cancer (31%), the difference was not significant(p=0.25). Conclusion: Eloesser procedure was an effective method for initial drainage of PPE cavity with low operative mortality. Given the findings of low spontaneous closure rate of BPF, aggressive approach to close the BPF is mandatory to achieve the final goal of chest wall closure. It was found that majority of patients still left their chest cavity opened, even after controlling the active inflammation of the empyema cavity. More aggnessive approach for chest wall closure is recommended in all patents with benign disease and in selective patients with lung cancer if there is no evidence of recurrence at several years after the initial operation.

• Journal of the Korean Society of Radiology
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• v.85 no.3
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• pp.581-595
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• 2024

Purpose The present study aimed to investigate the frequency and extent of compensatory common bile duct (CBD) dilatation after cholecystectomy, assess the time between cholecystectomy and CBD dilatation, and identify potentially useful CT findings suggestive of obstructive CBD dilatation. Materials and Methods This retrospective study included 121 patients without biliary obstruction who underwent multiple CT scans before and after cholecystectomy at a single center between 2009 and 2011. The maximum short-axis diameters of the CBD and intrahepatic duct (IHD) were measured on each CT scan. In addition, the clinical and CT findings of 11 patients who were initially excluded from the study because of CBD stones or periampullary tumors were examined to identify distinguishing features between obstructive and non-obstructive CBD dilatation after cholecystectomy. Results The mean (standard deviation) short-axis maximum CBD diameter of 121 patients was 5.6 (± 1.9) mm in the axial plane before cholecystectomy but increased to 7.9 (± 2.6) mm after cholecystectomy (p < 0.001). Of the 106 patients with a pre-cholecystectomy axial CBD diameter of < 8 mm, 39 (36.8%) showed CBD dilatation of ≥ 8 mm after cholecystectomy. Six of the 17 patients with long-term (> 2 years) serial follow-up CT scans (35.3%) eventually showed a significant (> 1.5-fold) increase in the axial CBD diameter, all within two years after cholecystectomy. Of the 121 patients without obstruction or related symptoms, only one patient (0.1%) showed IHD dilatation > 3 mm after cholecystectomy. In contrast, all 11 patients with CBD obstruction had abdominal pain and abnormal laboratory indices, and 81.8% (9/11) had significant dilatation of the IHD and CBD. Conclusion Compensatory non-obstructive CBD dilatation commonly occurs after cholecystectomy to a similar extent as obstructive dilatation. However, the presence of relevant symptoms, significant IHD dilatation, or further CBD dilatation 2-3 years after cholecystectomy should raise suspicion of CBD obstruction.

• Journal of Chest Surgery
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• v.38 no.7 s.252
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• pp.489-495
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• 2005

In the surgical treatment of aortic dissection, aortic arch replacement under total circulatory arrest is often performed after careful inspection to determine the severity of disease progression. Under circulatory arrest, antegrade or retrograde cerebral perfusion is required for brain protection. Recently, antegrade cerebral perfusion has been used more, because of the limitation of retrograde cerebral perfusion. This study is to compare these two methods especially in the respect to neurological complications. Material and Method: Forty patients with aortic dissection involving aortic arch from May 2000 to May 2004 were enrolled in this study, and the methods of operation, clinical recovery, and neurological complications were retrospectively reviewed. Result: In the ACP (antegrade cerebral perfusion) group, axillary artery cannulation was performed in 10 out of 15 cases. In the RCP (retrograde cerebral perfusion) group, femoral artery Cannulation was performed in 24 out of 25 cases. The average esophageal and rectal temperature under total circulatory arrest was $17.2^{\circ}C\;and\;22.8^{\circ}C$ in the group A, and $16.0^{\circ}C\;and\;19.7^{\circ}C$ in the group B, respectively. Higher temperature in the ACP group may have brought the shorter operation and cardiopulmonary bypass time. However, the length of period for postoperative clinical recovery and admission duration did not show any statistically significant differences. Eleven out of the total 15 cases in the ACP group and thirteen out of the total 25 cases in the RCP group showed neurological complication but did not show statistically significant difference. In each group, there were 5 cases with permanent neurological complications. All 5 cases in the ACP group showed some improvements that enabled routine exercise. However all 5 cases in RCP group did not show significant improvements. Conclusion: The Antegrade, cerebral perfusion, which maintains orthordromic circulation, brings moderate degree of hypothermia and, therefore, shortens the operation time and cardiopulmonary bypass time. We concluded that Antegrade cerebral perfusion is safe and can be used widely under total circulatory arrest.

• Journal of Yeungnam Medical Science
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• v.14 no.1
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• pp.209-219
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• 1997

Objectives: Anterior approach to achieve arthrodesis of the cervical spine has become a widely accepted and often-used approach since its earliest reports by Bailey and Badgley, Smith and Robinson and Cloward. However, anterior interbody fusion in the presence of the posterior instability may be complicated by the bone graft dislodgement, kyphotic defomity or nonunion. As an attemp to prevent this undesirable complication, additional methods such as skeletal traction, halo appratus or even posterior fusion has been utilized. Therefore, The cervical spine locking plate(CSLP) with the anterior intervertebral body bone grafting provide immediate cervical stabilization and widely successful in achieving fusion. Material and methods: This study analysed 14 patients who underwent a single anterior procedure and application of CSLP for the treatment of the cervical spinal disorder. Eleven patients were disc herniations and three patients were traumatic lesion. The average age of the patient was 47 years and the mean follow up periods was 20 months ranging from 13 to 27 months. Results: Ambulation was started 2nd day after the operation with the aid of the Philadelpia orthoses. Bone union was observed 13 cases on average 12 weeks after operation. The one case was nonunion with plate breakage without clinical symptom. Conclusion: Anterior fusion with CSLP are thought to be a safe and valuable method for treating cervical spine disorder.

• Journal of the korean academy of Pediatric Dentistry
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• v.34 no.3
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• pp.398-407
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• 2007

This study was performed to evaluate possibility to reduce treatment time for child patient who have limited control activity during flowable composite resin restoration according to comparing microleakage and shear bond strength. Group I, II with Single $Bond^{TM}$, group III, IV with AQ Bond $Plus^{TM}$, group V, VI with Prompt L-$Pop^{TM}$, and group VII as control group without adhesive system. 12 premolars and 10 molars were assigned into each group. Restorative material was used the Filtek $Z350^{TM}$ flowable. The results were as follows; 1. The result of microleakage evaluation, in the group I, II with Single $Bond^{TM}$ showed low dye penetration score. Dye penetration between group I and group II were similar. 2. Results for shear bond strength at group I and group II showed values higher than other groups. (p<0.05) There were no statistical differences between group I and group II. (p>0.05) 3. There was no statistical differences among I and II, III and IV, V and VI groups. 4. Group VII showed significantly low shear bond strength than group I, II, V, VI(p<0.05). Group VII showed low value than group with III and IV, but no statistical significances. In conclusion, adhesive bonding resin was not affect significantly to microleakage and shear bond strength of flowable resin restoration. Therefore, to reduce the operation time, adhesive bonding resin and flowable composite resin can be cured at once. But contamination of saliva, location of cavities can affect to bond strength in clinical field.

• Korean Journal of Medicinal Crop Science
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• v.7 no.3
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• pp.218-228
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• 1999

This study was conducted to obtain the information on dry matter productivity in Angelica gigas Nakai for establishing the cultivation method. Cultivation methods such as direct seeding on Mar. 31, Apr. 15 and Apr. 30, and transplanting of $8^{\frac{1}{2}}$, 9, 12 months old seedling were investigated. There were similar tendencies in changes of agronomic characters for all cultivation methods. Dry weight started to increase from 120 DAS. Direct seedling showed vigorous growth for aerial part, whereas transplanting showed better underground part. The quadratic polynomial was suitable to dry weight of root after 120 DAS (or DAT) .Short growing time had higher RGR and NAR independent of cultivation method but Direct seeding on Mar. 31 and transplanting of 9 months old seedling had the highest CGRs. LAI was positively correlated with CGR, and CGR had the highest value as $6.74\g/m^2/day$ when LAI was 1.97. RGR and NAR increased as mean temperature was increased and showed the highest value around . The highest net production of leaf and petiole was obtained at 20 and$23^{\circ}C$, respectively.