• Journal of Gastric Cancer
• /
• v.1 no.3
• /
• pp.168-173
• /
• 2001

Purpose: A positive esophageal margin is encountered in a total gastrectomy not infrequently. The aim of this retrospective review was to evaluate whether a positive esophageal margin predisposes a patient to loco-regional recurrence and whether it has an independent impact on long-term survival. Materials and Methods: A retrospective review of 224 total gastrectomies for adenocarcinomas was undertaken. The Chisquare test was used to determine the statistical significance of differences, and the Kaplan-Meier method was used to calculate survival rates. Significant differences in the survival rates were assessed using the log-rank test, and independent prognostic significance was evaluated using the Cox regression method. Results: The prevalence of esophageal margin involvement was $3.6\%$ (8/224). Univariate analysis showed that advanced stage (stage III/IV), tumor size ($\geq$5 cm), tumor site (whole or upper one-third of the stomach), macroscopic type (Borrmann type 4), esophageal invasion, esophageal margin involvement, lymphatic invasion, and venous invasion affected survival. Multivariate analysis demonstrated that TNM stage, venous invasion, and esophageal margin involvement were the only significant factors influencing the prognosis. All patients with a positive esophageal margin died with metastasis before local recurrence became a problem. A macroscopic proximal distance of more than 6 cm of esophagus was needed to be free of tumors, excluding one exceptional case which involved 15 cm of esophagus. Conclusion: All of the patients with a positive proximal resection margin after a total gastrectomy had advanced disease with a poor prognosis, but they were not predisposed to anastomotic recurrence. Early detection and extended, but reasonable, surgical resection of curable lesions are mandatory to improve the prognosis.

• Restorative Dentistry and Endodontics
• /
• v.18 no.2
• /
• pp.447-462
• /
• 1993

To evaluate the marginal leakage in Class V cavity this study has been undertaken to compare the sandwich technique with the conventional method, and find out the effect of lining material, lining method, and polishing time on sandwich technique. Ninty extracted teeth were divided into eight test groups and a control group, and were prepared with a buccal Class V cavity. Four test groups were lined with Dentin Cement whereas the other four test groups were lined with Vitrabond. Half of the either group were lined 0.5mm short of the carvosurface margin and the rest were lined completely to the carvosurface margin. The four subgroups were further divided into specimens which were polished immediately and 24 hours after resin filling. The polished specimens were immersed in $37^{\circ}C$, 0.5% methylene blue solution for 24 hous after thermocycling at $5^{\circ}C$ and $55^{\circ}C$, 200 times and buccolingually sectioned. The sectioned specimens were examined dye penetration under the light microscope. The following results were obtained, 1. At the enamel margin, the conventional method showed a lower microleakage than the sandwich technique. The difference between the control and Vitrabond group was statistically significant(P<0.05), but no difference between the control and Dentin Cement group, and between the lining materials was observed. 2. At the dentinal margin, the sandwich technique showed a significant lower amount of microleakage (P<0.05), but there was no significant difference between the lining materials. 3. Regardless of the lining material, lining method, and polishing time used, values of microleakage were significantly higher at the dentinal margin compared to the enamel margin(P<0.05). 4. In specimens till the cavosurface margin, microleakage at the dentinal margin was less with the light-cured base than with the chemically-cured base, but there was no siginificantly difference between the lining materials regarding the lining method and polishing time. 5. The lining material, lining method, and polishing time did not affect the amount of micro leakage in the sandwich technique(P<0.05).

• Environmental and Resource Economics Review
• /
• v.26 no.4
• /
• pp.499-517
• /
• 2017

The purpose of this article is to show profit margin hedging can be an optimal strategy in crude oil purchasing. This study theoretically analyzes profit margin hedging strategy is optimal in crude oil purchasing using expected target utility function and conducts simulations to show if the profit margin hedging is profitable. In addition, this study tests existence of mean reversion of crude oil futures prices to confirm the theory that profit margin hedging is more profitable than other strategies, such as always hedging or buying at expiration with spot price, if futures prices are mean reverting. The simulation results show that the expected utility of profit margin hedging higher than other strategies. Although we cannot find any evidence that crude oil futures prices follow mean reverting process, we can conclude that profit margin hedging can be optimal strategy in crude oil purchasing based on theoretical proof and simulation results.

• Journal of Chest Surgery
• /
• v.54 no.5
• /
• pp.361-368
• /
• 2021

Background: In general, a 2-cm surgical margin is recommended for limited resection to obtain equivalent oncologic outcomes to lobectomy for lung cancer. This study aimed to examine the patterns of recurrence and prognostic factors for recurrence in patients with a close parenchymal resection margin. Methods: From January 2009 to April 2017, 156 patients with stage I lung cancer who underwent segmentectomy with a close resection margin (<2 cm) were enrolled. Recurrence-free survival and overall survival were assessed. In addition, predisposing factors for recurrence were evaluated. Results: The mean tumor size was 1.7±0.8 cm and the parenchymal resection margin was 1.1±0.6 cm. Recurrence developed in 17 (10.7%) of the 156 patients, and the 5-year recurrence-free survival rate was 88.9%. Distant metastasis (7.7%) was the predominant recurrence pattern. The isolated local recurrence rate was 1.9%. Multivariate Cox regression analysis revealed that age, tumor size, mediastinal lymph node dissection, postoperative complications, and histologic type were significant predisposing factors for recurrence. However, parenchymal margin distance did not significantly affect the long-term prognosis. Conclusion: Segmentectomy with a close resection margin for early-stage lung cancer in selected patients resulted in acceptable recurrence and survival. However, patients with tumors larger than 2 cm, squamous cell carcinoma histology, and insufficient mediastinal evaluation should be carefully followed up for recurrence.

• The Korean Journal of Health Service Management
• /
• v.5 no.1
• /
• pp.77-85
• /
• 2011

The study intends to conduct an analysis of relations between efficiency of investment to human resources and the operating margin in hospitals. The analyzed results are as follows: First, it is found out that an index related to labor productivity(the monthly value added per bed, the value added ratio to gross revenue), and an index for efficiency of human resources(value added to personnel expenses), do not have a significant difference by years. Second, labor productivity, indicating the efficiency of human resources, does not have a significant difference between regions and between hospital types. But there is a significant difference according to types of establishment: private hospitals have higher labor productivity(efficiency of human resources) than corporate hospitals. The hospital size is small have significantly higher labor productivity. As a result of a follow-up check, it is found out that there is separation between a group with more than 200 beds and a group with less than 200 beds. Third, at the relations between the indices related to value-added productivity and the operating margin that the higher the value added ratio to gross revenue and the higher labor productivity, the higher the operating margin. Especially, labor productivity(value added to personnel expenses), an index for the efficiency of human resources, out of all the indices related value added productivity, has the most significant influence on the operating margin.

• Nuclear Engineering and Technology
• /
• v.22 no.1
• /
• pp.45-57
• /
• 1990

A steady-state margin comparison study was performed between analog and digital protection systems. The systems compared are the thermal overpower and overtemperature delta T system of Westinghouse, and Core Protection Calculator System of Combustion Engineering, Inc. No dynamic offset was considered to eliminate the margin differences by different safety analysis methodologies. The result shows that the digital protection system has about 30% more rated power margin than the analog system in protecting against the fuel rod centerline melting. The digital protection system is shown to have almost same margin with the analog protection system in preventing the DNB at EOC (End of Cycle) even if the digital protection system has about 10% more margin at BOC(Beginning of Cycle).

• Journal of Gastric Cancer
• /
• v.6 no.4
• /
• pp.277-283
• /
• 2006

Purpose: The way in which the resection margin distance for gastric cancer patients who undergo a gastric resection influences the recurrence rate, aspects of recurrence, and the prognosis according to the characteristic of the tumor is not known. We aim to find a standard for tailor-made treatment after selecting patients in this point of view who need a more sufficient resection margin. Materials and Methods: A retrospective study was done on 1,472 patients who underwent a gastrectomy due to gastric cancer at our hospital from 1992 to 2005. The median follow-up period was 37 months. Results: There were no significant differences in the recurrence rate, the aspects of recurrence, and the 5-year survival rate between early gastric cancer (EGC) patients with a resection margin distance of less than 2 cm compared with EGC patients with a resection margin distance of greater than 2 cm. However, significant differences in the survival rate were found in advanced gastric cancer (AGC) patients when the patients were classified into groups with resection margin distances less than or greater than 3 cm (P=0.02). Significant differences were noted especially in cases of diffuse histologic-type tumors located in the lower third of the stomach and in cases with Borrmann type-3 and -4 tumors. Conclusion: The distance between the tumor resection margin and the proximal gastric resection margin has no significant influence on the survival rate in EGC patients if the resection margin is negative. However, to improve a patient's survival rate, it is important to guarantee a resection margin of more than 3 cm in AGC patients, especially when the tumor is a diffuse histologic type located in the lower third of the stomach or a Borrmann type 3 and 4.

• Journal of Technologic Dentistry
• /
• v.2 no.1
• /
• pp.47-49
• /
• 1980

• Journal of the Korean Geophysical Society
• /
• v.9 no.3
• /
• pp.189-197
• /
• 2006

The Korea Plateau is a continental fragment rifted and partially segmented from the Korean Peninsulaat the initial stage of the opening of the East Sea (Japan Sea). We interpreted marine seismic profiles from the South Korea Plateau in conjunction with swath bathymetric to investigate processes of con-tjnental rifting and separation of the southwestern Japan Arc. The SouU-i Korea Plateau preserves funda-mental elements of rift architecture comprising a seaward succession of a rift basin and an uplifted rift flank passing into the slope, typical of a passive continental margin. Two distinguished rift basins (Onnuri and Bandal Basins) in the South Korea Plateau are bounded by major synthetic and smaller antithetic faults, creating wide and symmetric profiles. The large-offset border fault zones of these basins have convex dip slopes and demonstrate a zig-zag arrangement along strike. Rifting was primarily controlled by normal faulting resulting from extension orthogonal to the inferred line of breakup along the base ofthe slope rather U-ian strike-slip deformation. Two extension direcdons for rifdng are recog-nized; U-ie Onnuri Basin was rifted in U-ie EW direction; U-ie Bandal Basin in U-ie EW and NW-SE directions, suggesting two rift stages. We interpret that the E-W direction represents initial rifting at the inner margin; while the Japan Basin widened, rifting propagated repeatedly from the Japan Basin to the southeast toward the Korean margin but could not penetrate the strong continental lithosphere of the Korean Shield and changed direction to the south, resulting in E-W extension to create the rift basins at the Korean margin. The Hupo Basin to the south of the Korea Plateau is estimated to have formed in this process. The NW-SE direction probably represents the direction of rifting orthogonal to the inferred line of breakup along the base of the slope of the South Korea Plateau; after breakup the southwestern Japan Arc separated in the SE direction, indicating a response to tensional tectonics associated with the subduction of the Pacific Plate in the NE direction. We suggest that structural evolution of the eastern Korean margin can be explained by the processes occurring at the passive continental margin.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2009.06a
• /
• pp.153-153
• /
• 2009

We investigated the dependence of the memory margin of the Cap-less memory cell on the strain of top silicon channel layer and also compared kink effect of strained Cap-less memory cell with the conventional Cap-less memory cell. For comparison of the characteristic of the memory margin of Cap-less memory cell on the strain channel layer, Cap-less transistors were fabricated on fully depleted strained silicon-on-insulator of 0.73-% tensile strain and conventional silicon-on-insulator substrate. The thickness of channel layer was fabricated as 40 nm to obtain optimal memory margin. We obtained the enhancement of 2.12 times in the memory margin of Cap-less memory cell on strained-silicon-on-insulator substrate, compared with a conventional SOI substrate. In particular, much higher D1 current of Cap-less memory cell was observed, resulted from a higher drain conductance of 2.65 times at the kink region, induced by the 1.7 times higher electron mobility in the strain channel than the conventional Cap-less memory cell at the effective field of 0.3MV/cm. Enhancement of memory margin supports the strained Cap-less memory cell can be promising substrate structures to improve the characteristics of Cap-less memory cell.