• Journal of Gastric Cancer
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• v.5 no.2
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• pp.79-88
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• 2005

Quality assurance may be defined as the complete set of systemic actions that is required to achieve a better treatment result by standardizing treatment and by using various audit programs. In general, application of a quality assurance program in surgery is considered to be more difficult than it is in chemotherapy or radiotherapy. However, recently, the importance of quality assurance in the surgical field has been emphasized in clinical trials comparing different surgical procedures and evaluating the role of postoperative adjuvant therapy. In the case of gastric cancer surgery, excellent quality assurance programs have rarely been applied in most large prospective clinical trials. Although the quality assurance in Dutch trial was conducted very systemically and strictly, the situation is quite different from ours. On the other hand, several quality assurance programs in Japanese trials comparing D2 and D2 plus para-arotic lymph node dissection seem to be applicable to Korean clinical trials. Several factors, including selection of appropriate surgeons based on personal experience and annual number of operations, standardization of surgical procedures by education and consensus, development of a unified database program, application of standardized perioperative management, and standardization of pathologic examination, are required to guarantee a successful multi-institutional prospective clinical trial. In contrast, one needs to realize that protocols that are too strict and sophisticated can make the enrollment of patients and surgeons more difficult and can promote protocol violation during the clinical trials. (J Korean Gastric Cancer Assoc 2005;5:79-88)

• Food Engineering Progress
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• v.21 no.1
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• pp.79-87
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• 2017

This study was carried out to extract ginsenosides in by-products from honeyed red ginseng. Response surface methodology (RSM) was used to optimize the extraction conditions. Based on D-optimal design, independent variables were ethanol (extraction solvent) concentration (30-90%, v/v), extraction temperature ($25-70^{\circ}C$), and extraction time (5-11 h). Extraction yield (Y1) and total ginsenosides (Y2) in the extract were analyzed as dependent variables. Results found that extraction yield increased with increasing extraction temperature and time, whereas it was decreased with increasing ethanol concentration. Similar trends were found for the content of ginsenosides in the extracts, except for ethanol concentration, which was increased with increasing ethanol concentration. Regression equations derived from RSM were suggested to coincide well with the results from the experiments. The optimal extraction conditions for extraction yield and total ginsenosides were an extraction temperature of $56.94^{\circ}C$, ethanol concentration of 57.90%, and extraction time of 11 h. Under these conditions, extraction yield and total ginsenoside contents were predicted to be 84.52% and 9.54 mg/g, respectively.

• Journal of Chest Surgery
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• v.37 no.6
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• pp.482-491
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• 2004

Background: The xenogenic or allogenic valves after in Vitro repopulation with autologous cells or in vivo repo-pulation after acellularization treatment to remove the antigenicity could used as an alternative to synthetic polymer scaffold. In the present study, we evaluated the process of repopulation by recipient cell to the acellu-larized xenograft treated with NaCl-SDS solution and grafted in the right ventricular outflow tract. Material and Method: Porcine pulmonary valved conduit were treated with. NaCl-SDS solution to make the grafts acellularized and implanted in the right ventricular outflow tract of the goats under cardiopulmonary bypass. After evaluating the functions of pulmonary valves by echocardiography, goats were sacrificed at 1 week, 1 month, 3 months, 6 months, and 12 months after implantation, respectively. After retrieving the implanted valved conduits, histopathologic examination with Hematoxylin-Eosin, Masson' trichrome staining and immunohistochemical staining was performed. Result: Among the six goats, which had been implanted with acellularized pulmonary valved conduits, five survived the expected time period. Echocardiographic examinations for pulmonary valves revealed good function except mild regurgitation and stenosis. Microscopic analysis of the leaflets showed progressive cellular in-growth, composed of fibroblasts, myofibroblasts, and endothelial cells, into the acellularized leaflets over time. Severe inflammatory respon-se was detected in early phase, though it gradually decreased afterwards. The extracellular matrices were regenerated by repopulated cells on the recellularized portion of the acellularized leaflet. Conclusion: The acellularized xenogenic pulmonary valved conuits were repopulated with fibroblasts, myofibroblasts, and endothelial cells of the recipient and extracellullar matrices were regenerated by repopulted cells 12 months after the implantation. The functional integrity of pulmonary valves was well preserved. This study showed that the acellularized porcine xenogenic valved conduits could be used as an ideal valve prosthesis with long term durability.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.8 no.2
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• pp.193-204
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• 1998

The single crystal of the $LiTaO_3$has large electro-optic effects, so it is applied to optical switch, acousto-optic deflector, and optical memory device as hologram using photorefractive effect. In this study, optic-grade undoped $LiTaO_3$and Fe:LiTaO$LiTaO_3$single crystals were grown by the Czochralski method and optical transmission and absorption spectrums were measured in the wavelength of UV-VIS range. The curie temperature was determined with DSC and by measuring capacitance for the grown undoped crystal and ceramic powder samples of various Li/Ta ratio. In case of having a 48.6 mol% $Li_2O$ as a starting Li/Ta ratio, the results of concentration variations were below 0.01 mol% $Li_2O$ all over the crystal, so it was confirmed that $LiTaO_3$single crystals were grown under congruent melting composition having optical homogeneity. The curie temperature of the Fe:$LiTaO_3$crystal was increased with increased with increased doped Fe concentrations;by the ratio of $7.5^{\circ}C$ increase per Fe 0.1 wt%. Also, the optical transmittance was about 78 %, which was sufficient for optical device.

• Journal of Chest Surgery
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• v.39 no.1 s.258
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• pp.35-41
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• 2006

Background: The radial arteries are being used more often for coronary artery bypass grafting, We tried to the endoscopic radial artery harvest to reduce the cosmetic problems and neurologic complications of the conventional open harvesting and report the techniques and early results. Material and Method: The 86 patients underwent coronary artery bypass grafting between May 2003 and April 2005 had their nondominant radial artery endoscopically removed through a 2 cm incision at the wrist. The radial pedicle was dissected and was divided at antecubial area through a 5 mm counterincision. Result: The 23 patients complained of neuralgias on territory of superficial raidal none but no one complained of neuralgias on territory of lateral antebrachial cutaneous none. There was no functional impairment of the hand. There was no wound complication except a localized hematoma. All patients were contacted by telephone after postoperative 7.9$\pm$3.6 months. The 4 patients still complained of neuralgia. All the patients were satisfied with the aesthetics of the wounds. The multidetectional tomography was done on the 66 patients for the estimation of early patency of radial artery. There were 2 cases of stenosis and a case of occlusion. Conclusion: Endoscopic radial artery harvest had no functional impairment of the hand, lesser rate of neurologic complications and outstanding aesthetics. The results of early patency of the radial artery was similar to conventional methods. Therefore, we think that endoscopic radial artery harvest is the optimal procedure.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.10 no.3
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• pp.151-162
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• 1977

Distribution of marine algae is diverse in Korea and the resource of edible algae is abundant marking 239,037 tons of yearly production in 1976. They have been known as a protein source and used as a supplement in Korean diet. It is necessary to estimate the potentiality and properties of usable algal proteins especially as food resources and studies of extraction and separation of the proteins, therefore, are basically required for this purpose. In this study, the influence of various factors including the sample treatment, extraction time and temperature, sample us extraction solvent ratio and pH upon the extractability of the water soluble protein was determined. And the effect of precipitation treatment for isolation of the algal protein from the extracts was also tested. Nine species of algae, the major ones in consumption as food namely Porphyra suborbiculata, Undaria pinnatifida, Hizikia fusiforme, Sargassum fulvellu, Enteromorpha linza, Codium fragile, Sargassum kjellmanianum and Ulva pertusa were collected as fresh from Kijang, Yangsan Gun, in the vicinity of Busan city. The content of crude protein $(N\times6.25)$ of the algae ranged from $9.46\%\;to\;24.14\% showing the highest value in Porphyra suborbiculata and the minimum in Hizikia fusiforme. In the effort of maceration of blending methods on the extractability, immersion freezing in dry ice-methanol solution appeared most effective yielding 1.5 to 2.5 times extractability than that of the mortar grinding method. The effect of the ratio of sample vs solvent on extractability differed from species. It was enhanced at the ratio of 1:20 (w/v) in Ulva pertusa and Enteromorpha linza while the ratio was 1:30 (w/v) for Cedium fragile, Undaria pinnatifida, Hizikia fusiferme, Sargassum fulvellum and Porphyra suborbiculata and 1:40 for Sargassum kjellmanianum respectively. The effect of extraction time and temperature was revealed differently from species which might be caused by differences in the constitution of algal tissues resulting in that the extraction for 1 hour at $50^{\circ}C$ gave the maximum extractabilily in Ulva pertusa and Enteromorpha linza, 2 hours in Porphyra suborbiculata, Hikikia fusiforme, Undaria pinnatifida, Sargassum kjellmanianum and 3 hours in Codium fragile. And the extractability was higher at $50^{\circ}C$ to $60^{\circ}C$ for the most of the tested samples except Hizikia fusiforme. The optimum pH for the extraction was 9 to 12. The recovery of extractable nitrogen to the total nitrogen was $63\%$ in average with the first extracts and $8.6\%$ with the second extracts respectively. Both extracts were prepared by 2 hour extraction at $50{\pm}1^{\circ}C$ with dry ice-methanol frozen and seasand macerated materials. And these conditions assumed to be an optimum for the extraction of water soluble algal proteins since the nitrogen content after the first extraction covered $90\%$ of the total water extractable nitrogen. In the precipitation of the extracted proteins, Barnstein method and methanol treatment seemed to be more efficient than other precipitation methods.

• Journal of Chest Surgery
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• v.42 no.6
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• pp.710-718
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• 2009

Background: The Cox maze procedure has been used as a standard surgical treatment for atrial fibrillation for about 20 years. Recently, the creators have used a bipolar radiofrequency electrode (Cox maze IV procedure) instead of the incision and suture (cut-sew) technique to make atrial ablation lesions for persistent atrial fibrillation. We investigated clinical outcomes for the Cox maze procedure with a bipolar radiofrequency electrode and cryoablator in patients with persistent atrial fibrillation, and compared results with clinical outcomes of the cut-sew procedure. Material and Method: Between April 2005 and July 2007, 40 patients with persistent atrial fibrillation underwent Cox maze IV procedure with a bipolar radiofrequency electrode and cryoablator (bipolar radiofrequency group). Surgical outcomes were compared with those of 35 patients who had the cut-sew technique for the Cox maze III procedure. All patients had concomitant cardiac surgery. Postoperatively, the patients were followed up every 1 to 2 months. Result: At 6 months postoperatively, the conversion rate to regular sinus rhythm was not significantly different between the two groups: 95.0% for the bipolar radiofrequency ablation group; 97.1% for the cut-sew technique (p=1.0). At the end of the follow-up period, the conversion rate to regular sinus rhythm was also not significantly different (92.5% vs. 91.6%, p=1.0). In multivariate analysis using a Cox-regression model, the postoperative atrial dimension was an independent determinant of sinus conversion in the bipolar radiofrequency ablation group (hazard ratio 31, p=0.005). In the Cox-regression model for both groups, atrial fibrillation at 6 months postoperatively (hazard ratio 92.24, p=0.003) and the postoperative left atrial dimension (hazard ratio 16.05, p=0.019) were independent risk factors of continuance or recurrence of atrial fibrillation after Cox maze procedures. Aortic cross-clamp time and cardiopulmonary bypass time were significantly shorter in the radiofrequency group than in the cut-sew group. Conclusion: In the Cox maze procedure for patients with persistent atrial fibrillation, the use of bipolar radiofrequency ablation and a cryoablator is as good as the cut-sew technique for conversion to sinus rhythm. The postoperative left atrial dimension is an independent determinant of postoperative continuance and recurrence of atrial fibrillation.

• Geophysics and Geophysical Exploration
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• v.2 no.1
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• pp.26-32
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• 1999

Among the various seismic data processing sequences, the velocity analysis is the most time consuming and man-hour intensive processing steps. For the production seismic data processing, a good velocity analysis tool as well as the high performance computer is required. The tool must give fast and accurate velocity analysis. There are two different approches in the velocity analysis, batch and interactive. In the batch processing, a velocity plot is made at every analysis point. Generally, the plot consisted of a semblance contour, super gather, and a stack pannel. The interpreter chooses the velocity function by analyzing the velocity plot. The technique is highly dependent on the interpreters skill and requires human efforts. As the high speed graphic workstations are becoming more popular, various interactive velocity analysis programs are developed. Although, the programs enabled faster picking of the velocity nodes using mouse, the main improvement of these programs is simply the replacement of the paper plot by the graphic screen. The velocity spectrum is highly sensitive to the presence of the noise, especially the coherent noise often found in the shallow region of the marine seismic data. For the accurate velocity analysis, these noise must be removed before the spectrum is computed. Also, the velocity analysis must be carried out by carefully choosing the location of the analysis point and accuarate computation of the spectrum. The analyzed velocity function must be verified by the mute and stack, and the sequence must be repeated most time. Therefore an iterative, interactive, and unified velocity analysis tool is highly required. An interactive velocity analysis program, xva(X-Window based Velocity Analysis) was invented. The program handles all processes required in the velocity analysis such as composing the super gather, computing the velocity spectrum, NMO correction, mute, and stack. Most of the parameter changes give the final stack via a few mouse clicks thereby enabling the iterative and interactive processing. A simple trace indexing scheme is introduced and a program to nike the index of the Geobit seismic disk file was invented. The index is used to reference the original input, i.e., CDP sort, directly A transformation techinique of the mute function between the T-X domain and NMOC domain is introduced and adopted to the program. The result of the transform is simliar to the remove-NMO technique in suppressing the shallow noise such as direct wave and refracted wave. However, it has two improvements, i.e., no interpolation error and very high speed computing time. By the introduction of the technique, the mute times can be easily designed from the NMOC domain and applied to the super gather in the T-X domain, thereby producing more accurate velocity spectrum interactively. The xva program consists of 28 files, 12,029 lines, 34,990 words and 304,073 characters. The program references Geobit utility libraries and can be installed under Geobit preinstalled environment. The program runs on X-Window/Motif environment. The program menu is designed according to the Motif style guide. A brief usage of the program has been discussed. The program allows fast and accurate seismic velocity analysis, which is necessary computing the AVO (Amplitude Versus Offset) based DHI (Direct Hydrocarn Indicator), and making the high quality seismic sections.

• Journal of Chest Surgery
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• v.32 no.2
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• pp.97-107
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• 1999

Background: This study was designed to develop a Korean version of the heparin-coated vascular bypass shunt by using a physical dispersing technique. The safety and effectiveness of the thrombo-resistant shunt were tested in experimental animals. Material and Method: A bypass shunt model was constructed on the descending thoracic aorta of 21 adult mongrel dogs(17.5-25 kg). The animals were divided into groups of no-treatment(CONTROL group; n=3), no-treatment with systemic heparinization(HEPARIN group; n=6), Gott heparin shunt (GOTT group; n=6), or Korean heparin shunt(KIST group; n=6). Parameters observed were complete blood cell counts, coagulation profiles, kidney and liver function(BUN/Cr and AST/ ALT), and surface scanning electron microscope(SSEM) findings. Blood was sampled from the aortic blood distal to the shunt and was compared before the bypass and at 2 hours after the bypass. Result: There were no differences between the groups before the bypass. At bypass 2 hours, platelet level increased in the HEPARIN and GOTT groups(p<0.05), but there were no differences between the groups. Changes in other blood cell counts were insignificant between the groups. Activated clotting time, activated partial thromboplastin time, and thrombin time were prolonged in the HEPARIN group(p<0.05) and differences between the groups were significant(p<0.005). Prothrombin time increased in the GOTT group(p<0.05) without having any differences between the groups. Changes in fibrinogen level were insignificant between the groups. Antithrombin III levels were increased in the HEPARIN and KIST groups(p<0.05), and the inter-group differences were also significant(p<0.05). Protein C level decreased in the HEPARIN group(p<0.05) without having any differences between the groups. BUN levels increased in all groups, especially in the HEPARIN and KIST groups(p<0.05), but there were no differences between the groups. Changes of Cr, AST, and ALT levels were insignificant between the groups. SSEM findings revealed severe aggregation of platelets and other cellular elements in the CONTROL group, and the HEPARIN group showed more adherence of the cellular elements than the GOTT or KIST group. Conclusion: Above results show that the heparin-coated bypass shunts(either GOTT or KIST) can suppress thrombus formation on the surface without inducing bleeding tendencies, while systemic heparinization(HEPARIN) may not be able to block activation of the coagulation system on the surface in contact with foreign materials but increases the bleeding tendencies. We also conclude that the thrombo-resistant effects of the Korean version of heparin shunt(KIST) are similar to those of the commercialized heparin shunt(GOTT).

• Journal of Chest Surgery
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• v.30 no.9
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• pp.920-926
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• 1997

Remarkable effect of pain relief and prevention of the postoperative Complications after thoracotomy has been achieved by continuous intravenous analgesia. This study was carried out with thirty patients who underwent posterolateral thoraco tony. The patients were divided into three groups: Group I(n= 10), the patients with intermittent intramuscular analgesia(piroxicam 20 mg), Group II(n=10), the patients with continuous epidural analgesia(0.5% bupivacaine 30m1 + normal saline 30 ml + morphine 10 mg), and Group III(n= 10) the patients with controlled intravenous infusion of analgesics(fentanyl 2500 mfg +normal saline 10 ml). The results w re as follows; 1) There were no significant changes of vital signs, between groups. 2) Tidal volume and FVC were significantly improved in the group II and III compared with the group I during the first postoperative day. 3) A significant reduction of immediate post-thoracotomy pain was achieved in the group II and III compared with the group I. 4) The limitation of motion in the operative side was less in the group II and III compared with the group I. 5) A signi(icant reduction of the postoperative analgegics consumption was noticed in group II and III. 6) Significant complications were not occured during follow-up period in all groups.