• Journal of Korean Society of Environmental Engineers
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• v.27 no.8
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• pp.844-851
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• 2005

The purpose of this study was to determine feasibility of application of regenerated or recycled $TiO_2$ on the successive treatment of Cu(II)-EDTA. The recovery of copper, the reuse of $TiO_2$ and the assessment of acute toxicity was studied in the total eight successive photocatalytic reactions. Aqueous solution of $10^{-4}\;M$ Cu(II)-EDTA was treated using an illuminated $TiO_2$ at pH 6 in a circulating reactor. Two different procedures were applied in the reuse of $TiO_2$: i) recycle of $TiO_2$ without acid wash ii) regeneration of $TiO_2$ with acid wash to remove adsorbed copper in a previous experiment. The averaged decomplexation rate constant($k'_{obs}$) of Cu(II)-EDTA in recycle of $TiO_2$ without acid wash was approximately 45% less than that in regeneration of $TiO_2$ with acid wash. Removal of Cu(II) was near complete after 180 minutes in the total eight successive photocatalytic reactions using the regenerated $TiO_2$ after acid wash. In contrast, removal of Cu(II) was minimum at total fifth successive photocatalytic oxidation using the recycled $TiO_2$ without arid wash. The recovered $TiO_2$ was approximately 86% in average in each procedure. The recovered Cu(II) was 67.9% in average. The acute relative toxicity of the treated water rapidly declined at an initial reaction time up to 60 minutes but little declination was observed after 60 minutes due to little degradation of DOC. Relative toxicity of treated water using the recycled $TiO_2$ without acid wash we some what well correlated with the concentration of dissolved Cu(II). From this work, it is suggested that Cu(II)-EDTA can be effectively treated using an integrated cyclic photocatalytic oxidation with recovery of $TiO_2$ and Cu(II).

• Journal of Animal Science and Technology
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• v.47 no.4
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• pp.513-524
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• 2005

This study was conducted to introduce recycling procedures of food waste(FW) as feed according to the dehydration, semi-dehydration fermentation and liquid fermentation methods through the on-site survey of companies related, to trace physico-chemical components and nutritional losses depending upon the processing stage for each method and finally to suggest more desirable methodology for the efficient utilization of FW as animal feed. For the dehydration method, dewatering of FW alone reduced(P<0.05) moisture(approximately 10%) and ether extract contents and increased(P<0.05) fiber contents. Dewatering and subsequent dehydration of FW decreased(P<0.05) contents of ether extract, limiting amino acids such as lysine, methionine and histidine, pepsin digestibility of protein by half, and NaCl content by 40%, increased(P<0.05) contents of fiber, crude ash, Ca and P, and did not alter(P>0.05) pH. The semi-dehydration fermentation method of FW did not affect(P>0.05) the chemical components, pepsin digestibility of protein, pH and NaCl content. For the liquid fermentation method, pasteurization and fermentation of FW decreased(P<0.05) contents of dry matter, ether extract, crude fiber, lysine and NaCl; however, it did not affect(P>0.05) other chemical components, pepsin digestibility of protein and pH. Among the processing methods, nutrient losses were highest for the dehydration method(25% of metabolizable energy loss, 12% of organic matter loss) and little for the semi-dehydration and liquid fermentation methods. The on-site survey of companies related revealed that the existence of foreign materials in FW products were problematic for all the three companies surveyed, thus it was necessary to develop a more efficient screener. Before feeding FW-containing diets to pigs, high quality of protein and energy feedstuffs needed to be fortified for the dehydration method. For the semi-dehydration fermentation method, the scientific diet formulation technology was required at the initial mixing stage. For the liquid fermentation method, possibly most energetic and proteinaceous feeds needed to be supplemented for the normal animal growth.

• The Korean Journal of Pesticide Science
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• v.16 no.4
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• pp.343-349
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• 2012

Exposure and risk assessments were conducted to evaluate the relative safety of mixing/loading work of indoxacarb between wettable powder (WP) and water dispersible granule (WG). Hand exposure was monitored using cotton gloves while inhalation exposure was measured using personal air monitor. Method validation for the exposure monitoring was established successfully through several experiments. Limit of determination and limit of quantitation were 0.25 and 1 ng, respectively. $R^2$ of calibration curve linearity was more than 0.9999 and reproducibility was 0.7-6. Recovery of indoxacarb from gloves, solid sorbent and glass fiber filter at three different levels was 81.5-108.8%. Trapping efficiency and breakthrough tests gave 981.5-108.8% of recovery. During mixing/loading procedure, hand exposure amount (75 percentile of 30 repetitions) for indoxacarb WP was 6 folds (459.8 mg/kg a.i) than that of WG (81.4 mg/kg a.i). This result indicates that WG has less drift than WP thanks to its granular type of formulation. Inhalation amount was $10^{-8}-10^{-7}%$ of spray mixture prepared and $10^{-4}-10^{-3}%$ of hand exposure. In inhalation case, no significant differences were observed between two formulations. Margin of safety was calculated for risk assessment using male Korean average body weight and acceptable operator exposure level as the important exposure factors. Mixing/loading procedures for both of the formulations were considered to be of least risk because calculated MOS values were more than 1.

• Journal of Korea Technology Innovation Society
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• v.20 no.2
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• pp.334-367
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• 2017

The ICT industry has been the main driver of Korea's economy with international competitiveness and is expected to be the growth engine that will revitalize the currently depressed economy. A broad range of different perspectives and opinions on the industry exist in Korea and overseas. Some of these are stereotypes, not all of which are based on objective evidence. Stereotypes refer to widely-held fixed opinions on a specific group and do not necessarily have negative connotations. However, they should not be viewed lightly because they can substantially affect decision-making process. In this regard, this study sought to review the stereotypes of ICT industry and identify objective and relative stereotypes. In the study, a decision-tree analysis was conducted on a survey result of 3,300 small and medium-sized enterprises (SMEs) in order to identify Korean ICT companies' characteristics that distinguish them from other technology companies. The decision-tree analysis, a data mining process based on machine learning, took a total of 291 variables into account in 10 subjects such as: corporate business in general, technology development activities as well as organization and people in technology development. Identifying the variables that distinguish ICT companies from other technology companies with the decision-tree analysis, the study then came up with a list of objective stereotypes of ICT companies. The findings from the stereotypes of Korean ICT companies are as follows. First, the companies are in need of technology policies that help R&D planning and market penetration. Second, policies must better support the companies working to sell new products or explore new business. Third, the companies need policies that support secure protection of development outcomes and proper management of IP rights. Fourth, the administrative procedures related to governmental support for ICT companies' R&D projects must be simplified. It is hoped that the outcome of this study will provide meaningful guidance in establishment, implementation and evaluation of technology policies for ICT SMEs, particularly to policymakers or researchers in relevant government agencies who determine R&D policies for ICT SMEs.

• Korean Security Journal
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• no.39
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• pp.161-183
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• 2014

The job burnout of the private security guards who provide services through contact with customers can affect the overall the private security industry. So the managers need to make efforts to diagnose and evaluate the job burnout and provide continuous provision for the repatriation effect. However, up to the present, the job burnout measure for the private security guards has not been provided, so the objectivity of the information is questionable. For this reason, in order to establish the goodness of fit of the job burnout scale for private security guards based on the contents of the job burnout scale that was being provided to other service employees, this research aims to provide the scale to provide objective information compared with that of the past by applying the Rasch model of the item response theory. To achieve this purpose, the data on 379 private security guards working for the private security guard companies in the Gyeonggi region were collected, and the data were processed to suit the research purpose using SPSS 18.0 and AMOS 18.0, Winsteps programs. Through these research procedures, the following conclusion was obtained. With regard to the private security guards' measure of job burnout, as a result of factor analysis through the collected data, 4 questions were deleted, and as a result of the analysis of the goodness of the fit based on 18 questions, 4 questions were found to be inappropriate questions that did not satisfy the standard value, and the scope of the difficulty level of the questions from - 98 to 1.30 and the response reaction of a 5-point scale were found to suit the final private security guards' job burnout scale. In other words, the conclusion that it is appropriate to measure the private security guards job burnout scale with 3 factors and 13 questions was obtained. So if private security guards companies collect systematic data using the scale established in this research, and practice refresher training accordingly, they can reduce the private security guards' job burnout.

• Radiation Oncology Journal
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• v.19 no.1
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• pp.40-44
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• 2001

Purpose : To evaluate effect and tolerance of external beam radiotherapy for carcinoma of the prostate and define the optimal radiotherapeutic regimen. Materials and methods : We retrospectively analyzed the records of 60 patients with prostate cancer who were treated with external beam radiotherapy with curative intent in our institution between September, 1987 and March, 2000. Histologic diagnosis was established by transurethral resection or ultrasonography guided biopsy. The major presenting symptoms were a nodule at routine prostatic examination and frequency and urgency of urination, along with dysuria. The median age was 63 years with range of 51 to 87 years. There were 6 patients in Stage A, 20 in Stage 8, 26 in Stage C, and 8 in Stage Dl. All patients were treated with megavoltage equipment producing 10 MV photons. The 4 field pelvic brick technique was used to a dose of 45 Gy or 50.4 Gy at 1.8 Gy per day in 5 to 6 weeks, after which a small boost field was delivered 2.0 Gy per day to a total dose of 66 to 70 Gy. The follow-up period ranged from 1 to 8 years. Results : Actuarial 5-year and 7-year survival rates for Stage A, B, C, and D1 were $100\%\;and\;84\%$, $83\%\;and\;72\%$, $67\%\;and\;54\%$, and $v$, respectively. The corresponding 5-year and 7-year relapse free survival rates were $84\%\;and\;84\%$, $77\%\;and\;67\%$, $48\%\;and\;40\%$, and $33\%\;and\;25\%$, respectively. Relapse free 5-year survival rates for Stage B were $80\%,\;80\%,\;and\;50\%$ for well, moderately, and poorly differentiated tumors, respectively. These were $64\%,\;44\%,\;and\;33\%$ for Stage C, respectively. The local control rates at 5 years were $84\%,\;85\%,\;78\%,\;and\;60\%$ for Stage A, B, C, and D1, respectively. Mild to moderate complications were observed in $22\%$ of patients. Severe complications requiring surgical procedures were documented in only $3\%$ of patients. Conclusion : This study confirms that external beam irradiation is an effective and safe treatment for prostatic cancer, providing long-term local control and good survival with acceptable complications.

• Journal of Chest Surgery
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• v.38 no.7 s.252
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• pp.476-482
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• 2005

Recently, coronary artery obstructive disease and coronary artery bypass graft surgery have increased, and the operative result has been improved. We reviewed 154 cases of coronary artery bypass graft surgery from Jan. 1985 to Jun. 2004. Material and Method: We reviewed 148 patients, 154 cases of coronary artery bypass surgery from Jan. 1985 to Jun. 2004. This investigation is designed to illustrate the preoperative diagnosis, severity of disease, operative method, the kind of used bypass graft used, number of distal anasomosis, associated surgery, and postoperative morbidity and mortality. Result: There were 84 males, 64 females and the average age was $58.9\pm8.3$ years old. Preoperative clinical diagnosis were unstable angina in 97 cases $(63.0\%)$, stable angina in 31 cases $(20.1\%)$, acute myocardial infarction in 12 cases $(7.8\%)$ and postinfartion angina in 14 cases $(9.1\%)$. Preoperative angiographic diagnosis were three-vessel disease in 68 $(44.2\%)$, two-vessel disease in 39 $(25.3\%)$, one-vessel disease in 35$(22.7\%)$, and left main disease in 12$(7.8\%)$ cases. There were 78 cases of on-pump coronary artery bypass graft surgery and 76 cases of off-pump coronary artery bypass graft surgery. The total distal anastomoses number was 319, mean number of anastomoses was $2.06\pm0.96$. There were 10 concomitant procedures. Postoperative intra-aortic balloon pump was used in 21$(13.6\%)$ cases, but only 4 cases were used at off-pump coronary artery bypass surgery. Total early mortality was $7.8\%$. The mortality was decreased as $4.5\%$ from Jan. 2001 to Jun. 2004. Post operative complication was perioperative yocardial infarction in 9cases$(5.8\%)$, low cardiac output syndrome in 17 cases$(11\%)$, and arrhythmia in 30 cases$(19.5\%)$ cases. Conclusion: Since 1985, The result of coronary artery bypass graft surgery has been improved because of more refined technique, use of off-pump coronary artery bypass surgery, use of internal thoracic artery and radial artery as bypass graft. We should study the long-term follow up more for better operative results.

• Journal of Chest Surgery
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• v.35 no.2
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• pp.102-112
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• 2002

This study was undertaken to analyze the outcome of composite valve graftreplacement(CVGR) for the treatment of aneurysms of the ascending aorta involving the aortic root. Material and Method: Between April 1995 and June 2001, 56 patients had replacement of the ascending aorta and aortic root with a composite graft valve and were reviewed retrospectively. Aortic regurgitation was present in 50 patients(89%), Marfan's syndrome in 18 patients(32%), and bicuspid aortic valve in 7(12.5%). The indications for operation were annuloaortic ectasia(AAE) in 30 patients(53.6%), aortic dissection in 13(23.2%), aneurysms of the ascending aorta involving aortic root in 11(19.6%), and aortitis in 2(3.6%). Cardiogenic shock due to the aortic rupture was present in 2 patients. Nine patients(16%) had previous operations on the ascending aorta or open heart surgery. The operative techniques used for CVGR were the aortic button technique in 51 patients(91%), the modified Cabrol technique in 4, and the classic Bentall technique in 1. The concomitant procedures were aortic arch replacement in 24 patients(43%), coronary artery bypass graft in 8(14.3%), mitral valve repair in 2, redo mitral valve replacement in 1, and the others in 7 The mean time of circulatory arrest, total bypass, and aortic crossclamp were 21$\pm$14 minutes, 186$\pm$68 minutes, and 132$\pm$42 minutes, respectively. Result: Early mortality was 1.8%(1/56). The postoperative complications were left ventricular dysfunction in 16 patients(28.6%), reoperation for bleeding in 7(12.5%), pericardial effusion in 2, and the others in 7. Fifty-three patients out of 55 hospital survivors were followed up for a mean of 23.2 $\pm$ 18.7 months(1-75 months). There were two late deaths(3.8%) including one death due to the traumatic cerebral hemorrhage, and CVGR-related late mortality was 1.9%. The 1- and 6-year actuarial survival was 98.1$\pm$1.9% and 93.2$\pm$5.1%, respectively. Two patients required reoperation for complication of CYGR(3.8%) and two other patients required subsequent operations for dissection of the remaining thoracoabdominal aorta. The 1- and 6-year actuarial freedom from reoperation was 97.8$\pm$2.0% and 65.3$\pm$26.7%, respectively.

• Journal of Chest Surgery
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• v.36 no.4
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• pp.242-254
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• 2003

Most of the studies conducted have investigated the beneficial effects of ischemic preconditioning on normothermic myocardial ischemia. However, the effect of preconditioning could be attenuated through the use of multidose cold cardioplegia as practiced in contemporary clinical heart surgical procedures. The purpose of this study was to investigate whether preconditioning improves postischemic cardiac function in a model of 25℃ moderate hypothermic ischemic heart induced by cold cardioplegia in isolated rat hearts. Material and Method: The isolated Sprague-Dawley rat hearts were randomly assigned to four groups. All hearts were perfused at 37℃ for 20 minutes with Krebs-Henseleit solution before the baseline hemodynamic data were obtained. Group 1 consisted of preconditioned hearts that received 3 minutes of global ischemic preconditioning at 37℃, followed by 5 minutes of reperfusion before 120 minutes of cardioplegic arrest (n=6). Cold (4℃) St. Thomas Hospital cardioplegia solution was infused to induce cardioplegic arrest. Maintaining the heart at 25℃, infusion of the cardioplegia solution was repeated every 20 minutes throughout the 120 minutes of ischemic period. Group 2 consisted of control hearts that underwent no manipulations between the periods of equilibrium and 120 minutes of cardioplegic arrest (n=6). After 2 hours of cardioplegic arrest, Krebs solution was infused and hemodynamic data were obtained for 30 minutes (group 1, 2: cold cardioplegia group). Group 3 received two episodes of ischemic preconditioning before 30 min of 37℃ normothermic ischemia and 30 minutes of reperfusion (n=6). Group 4 served as ischemic controls for group 3 (group 3, 4: warm ischemia group). Result: Preconditioning did not influence parameters such as left ventricular systolic pressure (LVSP), left ventricular end-diastolic pressure (LVEDP), rate-pressure product (RPP) and left ventricular dp/dt (LV dp/dt) in the cold cardioplegia group. (p=NS) However, preconditioning before warm ischemia attenuated the ischemia induced cardiac dysfunction, improving the LVSP, LVEDP, RPP, and LVdp/dt. Less leakage of CPK and LDH were observed in the ischemic preconditioning group compared to the control group (p<0.05). Conclusion: Ischemic preconditioning improved postischemic cardiac function after warm ischemia, but did not protect cold cardioplegic hearts.

• Journal of Chest Surgery
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• v.37 no.1
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• pp.43-49
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• 2004

Background: Acute thoracic aortic dissections involving the aortic arch differ in diagnosis, surgical procedures, and operative results compared to those that do not involve the aortic arch. In general cerebral perfusion under deep hypothermic circulatory arrest (HCA) is performed during the repair of the aortic arch dissection. Here, we report our surgical results of the aortic arch dissection repair using retrograde cerebral perfusion (RCP) and its safety. Material and Method: Between January 1996 and June 2002, 22 consecutive patients with aortic arch dissection underwent aortic arch repair. In 20 of them RCP was performed under HCA. RCP was done through superior vena cava in 19 patients and by systemic retrograde venous perfusion in 1, in whom it was difficult to reach the SVC. When the patient's rectal temperature reached 16 to 18$^{\circ}C$, systemic circulation was arrested, and the amount of RCP amount was 481.1 $\pm$292.9 $m\ell$/min with perfusion pressure of 20∼30 mmHg. Result: There were two in-hospital deaths (4.5%) and one late death (9.1%). Mean circulatory arrest time (RCP time) was 54.0$\pm$ 13.4 minutes (range, 7 to 145 minutes). RCP time has no correlation with the appearance of consciousness, recovery of orientation, or ventilator weaning time (p=0.35, 0.86, and 0.92, respectively). Ventilator weaning was faster in patients with earlier recovery of consciousness and orientation (r=0.850, r=926; p=0.000, respectively). RCP of more than 70 minutes did not affect the appearance of consciousness, recovery of orientation, ventilator weaning time, exercise time, or hospital stay (p=0.42, 0.57, 0.60, 0.83, and 0.51, respectively). Conclusion: Retrograde cerebral perfusion time under hypothermic circulatory arrest during repair of aortic arch dissection may not affect recovery of orientation, ventilator weaning time, neurologic complications, and postoperative recovery.