• The Korean Journal of Malacology
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• v.29 no.2
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• pp.91-96
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• 2013

Although the method of seedling production of Haliotis discus hannai is well known, the optimum benthic diatom species as a live food at early larval stage are not fully developed. In this study three Pennales diatom species, Caloneis schroederi, Rhaphoneis sp., and Cocconeis californica were examined on settlement, metamorphosis, survival, and growth of Haliotis discus hannai larvae. The larvae fed Raphoneis sp. or C. californica showed high settlement rate with 80-82% within 48 hrs, which was significantly higher than those fed C. schroederi or mixed diets with three diatom species. The larvae fed the former microalgal species also showed higher metamorphosis rate with 32-34% than the latter species with 10-12% within 4 days. With regard to survival and growth of the larvae, single diet with Rhaphoneis sp. or C. californica had better dietary value than the mixed diets for the early larvae of H. discus hannai.

• Journal of Chest Surgery
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• v.37 no.4
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• pp.328-334
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• 2004

There are only limited numbers of reports about long-term results of tricuspid valve replacement(TVR) with bioprosthetic and mechanical prostheses. We analyzed risk factors for tricuspid valve replacement and compared long-term clinical results of bioprosthetic and mechanical valves in tricuspid position. Material and Method: We reviewed 77 cases of TVR, which were performed between October 1978 and December 1996. Mean age was 38.8 15.9 years. Bioprostheses were implanted in 26 cases and mechanical prostheses were implanted in 51 cases. Result The operative mortality was 15.6% and late mortality was 12.3%. Survival for bioprosthetic and mechanical valve group at 5, 10 and 13 years was 81.3% vs. 100%, 66.1% vs. 100%, 60.6% vs. 100% (p=0.0175). Free from valve related re-operation for bioprosthetic and mechanical valve group at 5, 10 and 13 years was 100% vs. 93.9%, 100% vs. 93.9% and 58.3% vs. 93.9% (p=0.3274). Linealized incidences of valve related re-operation for bioprosthetic and mechanical valve group was 2.27 %/patient-years and 1.10 %/patient-years. Risk factor analysis showed that presence of preoperative ascites, hepatomegaly larger than 2 finger breaths, poor preoperative NYHA functional class and number of tricuspid valve replacement were risk factors for early mortality, and the use of bioprosthetic valve and number of open heart surgery were risk factors for late mortality. Conclusion: Long-term survival of mechanical valve was superior to bioprosthetic valve in tricuspid position. We recommend mechanical valve in tricuspid position if the patient can be closely followed up.

• Journal of Gastric Cancer
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• v.6 no.4
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• pp.244-249
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• 2006

Purpose: Tumor size has been reported to be one of the prognostic factors in the preoperative setting and 8 cm has been confirmed as a cut-off value for large gastric tumors with respect to postoperative complications. The aim of this study was to investigate the clinicopathologic features and the prognosis in patients with tumors larger than 8 cm in diameter. Materials and Methods: We retrospectively studied 2,260 patients with gastric cancer who underwent a gastrectomy from 1983 to 2001 at the Department of Surgery, Korea University College of Medicine. For a comparative analysis we divided the cases into the large and the small groups according to tumor size. The clinicopathological factors associated with large gastric tumors were analyzed by using univariate and multivariate analyses. To determine which variables were independent prognostic factors for overall survival, we applied the Cox proportional hazards model and we used P<0.05 as the cutoff value for statistical significance. Results: Univariate and multivariate analyses disclosed that tumor location (P<0.001), resection type (P<0.001), curability (P<0.001), depth of invasion (P<0.001), number of metastatic lymph nodes (P<0.001), differentiation (P<0.001) and combined resection (P<0.001) were significantly different between the two groups. The independent factors for survival identified by using the Cox proportional hazards model for large gastric tumors were nodal status (P<0.001), curative resection (P<0.001), depth of invasion (P=0.010), type of resection (P=0.018) and age (P=0.033). Conclusion: Large gastric tumors showed more aggressive local findings than their smaller counterparts. In patients with large gastric tumors, a curative resection was the most important factor for the prognosis. Therefore, we suggest that every effort should be made to do a curative gastrectomy and an accurate preoperative examination. (J Korean Gastric Cancer Assoc 2006;6:244-249)

• Korean Journal of Environmental Agriculture
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• v.26 no.1
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• pp.77-84
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• 2007

A fungus, Aspergillus sp. PS-104, with the high phosphate-solubilizing activities was isolated from Korean upland soil and formulated into a solid powder type with various additives. For the long-time preservation of conidia, some additives (Tween 80, SDS, Triton X-100, glucose, glycerol, corn oil, bio-ceramic, PEG 200, $Cu^{++}$, $Mo^{+++}$, $Fe^{++}$, $Ca^{++}$ and $Zn^{++}$) were supplemented in the rice-cooked hard medium with various concentrations (0, 0.001, 0.01, 0.1, 1.0 and 5.0%). In case of surfactants. the highest relative viability of the Aspergillus sp. PS-104 conidia was recorded nearly to 80% by the addition of 0.01 to 0.1% Tween 80, while 50% in control. The number of conidia were found to be about 100 times higher when treated at 0.01 to 0.1% Tween 80 as compared to control. Relative viability of the conidia was decreased in order of Tween 80 $\geq$ SDS > Triton X-100 during the storage at $25^{\circ}C$. As regards the organic additives, the relative viability of Aspergillus sp. PS-104 conidia was also recorded nearly to 80% by the addition of 1.0% bio-ceramic, and 5.0% glucose and sucrose during the storage at $25^{\circ}C$. In case of metal ions, the relative viability of Aspergillus sp. PS-104 conidia was decreased in order of $Cu^{2+}>Ca^{2+}>Mo^{3+}>Zn^{2+}>Fe^{2+}$ during the storage at $25^{\circ}C$.

• Journal of Chest Surgery
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• v.38 no.2 s.247
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• pp.157-163
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• 2005

Background: Clinical outcomes of esophageal cancer have not been satisfactory in spite of the development of surgical skills and protocols of adjuvant therapy. We analyzed the results of corrective surgical patients for esophageal cancer from January 1992 to July 2002. Material and Method: Among 129 patients with esophageal cancer, this study was performed in 68 patients who received corrective surgery. The ratio of sex was 59 : 9 (male : female) and mean age was $61.07\pm7.36$ years old. Chief complaints of this patients were dysphagia, epigastric pain and weight loss, etc. The locations of esophageal cancer were 4 in upper esophagus, 36 in middle, 20 in lower, 8 in esophagogastric junction. 60 patients had squamous cell cancer and 7 had adenocarcinoma, and 1 had malignant melanoma. Five patients had neoadjuvant chemotherapy. Result: The postoperative stage I, IIA, IIB, III, IV patients were 7, 25, 12, 17 and 7, respectively. The conduit for replacement of esophagus were stomach (62 patients) and colon (6 patients). The neck anastomosis was performed in 28 patients and intrathoracic anastomosis in 40 patients. The technique of anastomosis were hand sewing method (44 patients) and stapling method (24 patients). One of the early complications was anastomosis leakage (3 patients) which had only radiologic leakage that recovered spontaneously. The anastomosis technique had no correlation with postoperative leakage, which stapling method (2 patients) and hand sewing method (1 patient). There were 3 respiratory failures, 6 pneumonia, 1 fulminant hepatitis, 1 bleeding and 1 sepsis. The 2 early postoperative deaths were fulminant hepatitis and sepsis. Among 68 patients, 23 patients had postoperative adjuvant therapy and 55 paitents were followed up. The follow up period was $23.73\pm22.18$ months ($1\~76$ month). There were 5 patients in stage I, 21 in stage 2A, 9 in stage IIB, 15 in stage III and 5 in stage IV. The 1, 3, 5 year survival rates of the patients who could be followed up completely was $58.43\pm6.5\%,\;35.48\pm7.5\%\;and\;18.81\pm7.7\%$, respectively. Statistical analysis showed that long-term survival difference was associated with a stage, T stage, and N stage (p<0.05) but not associated with histology, sex, anastomosis location, tumor location, and pre and postoperative adjuvant therapy. Conclusion: The early diagnosis, aggressive operative resection, and adequate postoperative treatment may have contributed to the observed increase in survival for esophageal cancer patients.

• Journal of Chest Surgery
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• v.39 no.2 s.259
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• pp.106-110
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• 2006

Background: Bronchioloalveolar carcinoma (BAC) is an uncommon primary malignancy of the lung, and it accounts for $2{\~}14\%$ of all pulmonary malignancies. According to World Health Organization (WHO) categorisation, BAC is a subtype of adenocarcinoma. The current definition of BAC includes the following: malignant neoplasms of the lung that have no evidence of extrathoracic primary adenocarcinoma, an absence of a central bronchogenic source, a peripheral parenchymal location, and neoplastic cells growing along the alveolar septa. Previous reports had demonstrated a better prognosis following surgery for patients affected by BAC than those affected by other type of non-small cell lung cancer (NSCLC). We aim to analyse Asan Medical Center experiences of BAC. Material and Method: Between 1990 and 2002, 31 patients were received operations for BAC. We analyse retrosepectively sex, age, disease location, preoperative clinical stage, postoperative pathologic stage & complications, survival according to medical record. Result: There were 12 men and 19 women, the average age was 61.09$\pm$10.63 ($31{\~}79$) years. Tumor locations were 7 in RUL, 1 in RML, 4 in RLL, 8 in LUL, 11 in LLL. Operations were 28 lobectomies, 2 pneumonectomies. Postoperative pathologic stage were 12 T1N0M0, 15 T2N0M0, 1 T1N1M0, 1 T1N2M0, 1 T2N2M0, 1 T1N0M1. Mortality were 4 cases ($12.9\%$) and there were no early mortality. Cancer free death was 1 cases, other 3 were cancer related deaths. All of them were affected by distal metastasis and received chemotherapy and each metastatic locations were right rib, brain, and both lung field. The average follow up periods were 50.87$\pm$24.77 months. The overall 3, 5-year survival rate among all patients was $97.1\%,\;83.7\%$, stage I patients overall 2, 5year survival rate was $96.3\%$. The overall disease free 1, 2, 5-year survival rate among all patients was $100\%,\;90\%,\;76\%$ and 2, 5-year survival rate in cases of stage I was $96.4\%,\;90.6\%$. 7 cases ($22.58\%$) were chemotherapies, 1 case ($3.22\%$) was radiation therapy, and 2 cases ($6.45\%$) were chemoradiation therapies. Metastatic locations were 3 cases in lung, 1 case in bone, 1 cases in brain. Conclusion: BAC has a favourable survival and low recurrence rate compare with reported other NSCLC after operative resections.

• Tuberculosis and Respiratory Diseases
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• v.43 no.3
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• pp.331-338
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• 1996

Background : Lung cancer continues to be the leading cause of cancer death in the United States and it's incidence has been rapidly increasing in Korea, too. The overall cure rate for non-small cell lung cancer(NSCLC) is approximately 10%, and the cure is generally achieved by surgery. Unfortunately, however, less than 15% of all patients and less than 25% of those who present with localized disease are candidates for curative surgical resection. So preoperative staging evaluation followed by curative resection has a major role in determining the long tenn prognosis of NSCLC patients. Therefore, we have conducted this study to compare pre-operative and post-operative staging and the long-tenn relapse-free survival rates in NSCLC patients according to its stage. Methods : We analyzed the medical records of 217 NSCLC patients who were operated on for curative resection in Seoul National University Hospital, retrospectively. Among them, 170 patients who were completely resected were selected to determine the long term relapse-free survival rates. Results : Among 217 NSCLC patients, men were 157 and women were 30. The median age was 58 and the difference between men and women was not found. The discrepancy rate between preoperative and postoperative staging was 40.1%. Its major cause was due to the difference of nodal staging. The 3-year relapse-free survival rates were 73%, 53% and 48% in stage I, II and IIIa, respectively. There was no difference of relapse-free duration in recurred patients according to the stage or histologic types. Conclusion : The postoperative pathologic staging determines the long tenn prognosis of patients with NSCLC after surgery, but current preoperative clinical staging can not predict the postoperative pathologic staging correctly. So the improved modality of staging system is required to predict the pathologic staging more correctly.

• Radiation Oncology Journal
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• v.16 no.1
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• pp.27-33
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• 1998

Purpose : To improve the therapeutic results of postoperative recurrent disease and inoperable disease of stomach cancer, we used the thermoradiotherapy. We conducted a retrospective analysis of the results and compared the results of hyperthermia before radiotherapy and those of hyperthermia after radiotherapy Materials and Methods : From July 1994 to November 1996, we treated twenty patients with locally advanced stomach cancer and recurrent stomach cancer with thermoradiotherapy. We divided those patients into two groups : hyperthermia before radiotherapy group (PreRT group : 13 Patients) and hyperthermia after radiotherapy group (PostRT group : 7 patients). We performed radiation therapy with the total tumor dose of 3000-5040cGy in a traction of 180-300cGy and 5 fractions per week. Hyperthermia was performed with 8 MHz radiofrequency apparatus. PreRT group patients were treated daily for 30 minutes before the radiation therapy within the interval of ten minutes. And PostRT group patients were treated with 1-2 sessions Per week for 40-60 minutes after the radiation therapy within the interval of 10 minutes. Results : Overall response rate was $33.3\%$. This response rate appeared the same in both groups. Mean survival and 1 rear survival rate were 10.3 months and $16.5\%$. In PreRT group, mean survival and 1 year survival rate were 6.8 months and $9.0\%$, and in PostRT group, mean survival and 1 year survival rate were 7.7 months and $34\%$. There were no statistically significant difference between the prognostic factors and therapeutic results. Conclusion : The thermoradiotherapy was a safe treatment method in advanced and recurrent gastric cancer when compared with other treatment. Because the number of patients we treated was small and the follow up period was short. we were not able to draw any conclusions about the therapeutic efficacy of the sequence of radiation therapy and hyperthermia. Therefore, further clinical trials of thermoradiotherauy for stomach cancer appear to be warranted.

• Journal of Chest Surgery
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• v.29 no.9
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• pp.977-982
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• 1996

Cardiac valve implantation was performed in 107 patients from September, 1988 to May, 1995. There were 3) men and 74 women, whose ages ranged from 19 to 75 years(mean 42.6$\pm$11.7). Mitral valve was implanted in 61 patients, double(mitral & aortic) valve were Implanted in 28 patients and aortic valve was implanted in 18 patients. Follow up was 100% complete, with 345.6 patient-years and a mean fo low up of 41 months(from 1.5 to 84 months). The total mortality was 14.9%(16 patients). The early mortality was 5.6%(6 patients) and the late mortality was 9.3%(10 patients). The overall actuarial survival was 92.6 $\pm$ 2 6% at 2 years, 88.6$\pm$3.8% at 6 years. The probability of freedom from valve failure, thromboembolism and bacterial endocarditis were 388.6 $\pm$ 3.8, 88.3 $\pm$3.9, 89.5 $\pm$3.7 at 6 years, respectively.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2004.05a
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• pp.327-330
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• 2004

고객의 만족도와 충성도 제고는 기업활동 중 가장 중요한 기능으로 인식되고 있다. 따라서, 고객 이탈율이 높고 신규 고객 확보 경쟁이 치열한 초고속 인터넷 서비스 산업에서는 고객 만족도와 충성도의 증대를 통하여 고객 유지율을 제고하고 이를 통한 장기적인 수익성 증대를 위한 노력의 일환으로 막대한 경영자원을 투입하고 있다. 하지만 실제 서비스에 만족하고 충성도가 높은 고객이 기업의 수익성 확보에 기여하는 지에 관련해서는 그 실증 연구가 거의 이루어지고 있지 않다. 본 연구에서는 국내 한 초고속 인터넷 서비스 회사의 고객을 대상으로, 생존분석(survival analysis)을 이용한 개별 고객의 총 서비스 가입기간 추정을 통해 각 개별 고객의 가치를 산출하고, 이를 기반으로 고객의 만족도와 충성도, 수익성간의 연관 관계를 파악하였다. 분석 결과, 일반적인 예상과는 달리 높은 만족도와 충성도가 고객 서비스 이용 기간의 증대에 기여하지는 않는 것으로 밝혀졌다. 또한, 만족도 및 충성도와 수익성 간에 정(+)의 관계가 존재하지 않는 것으로 나타났다.