• The Journal of the Korean bone and joint tumor society
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• v.12 no.1
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• pp.37-46
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• 2006

Purpose: To evaluate the end results between the surgical treatment with neo-adjuvant chemotherapy in Korea and non-invasive high intensity focused ultrasound (HIFU) technique in China for osteogenic sarcomas. Materials and Methods: The surgical treatment with neoadjuvant chemotherapy for total 67 cases (4 IIA, 58 IIB, and 5 III) in Korea since 1993 and the HIFU therapy for total 71 cases (57 II and 14 III) in China since 1997 was performed. In Korea, neo-adjuvant chemotherapy in 66 cases out of total 67 patients, but the adjuvant chemotherapy in only one case was done. On the contrary, in China, full chemotherapy for more than 9 times for 37 patients with stage II out of total 71 cases, but for less than 8 times of partial chemotherapy for 23 patients (stage II) and 14 patients (stage III) was done. The surgical treatment in total 67 Korean patients was done with wide resection and reconstruction for 56 patients, but wide resection without reconstruction for 5 patients and amputation for 6 patients. In china, total 71 patients was treated with average 1.5 times (1~4 times) of HIFU, and if there are some evidences of residual tumor after HIFU with following MRI, the second HIFU therapy was given 2~4 weeks later. After then, the bony defect was in no touch, keep bracing for long time expecting regeneration. All of them were followed for average 46 Mo (12~150 Mo) in Korea, but followed for average 22 Mo (9 years~8 months) in China. Results: The 5 year survival rate (stage II), was average 92.7% (IIA 100%, IIB 85.5%) in Korea series, and average 78.7% (full chemotherapy 91.8%, part chemotherapy 56.6%) in China series. The 3 year survival rate (stage III) was 20% in Korea and 7.1% in China. So, the final overall survival rate was 65.2% in Korea and 51.8% in China. The overall functional outcome score by ISOLS was 24.3 (81%) in Korea and 19.8 (73%) in China. There are 25.4% (17/67 cases) of complications in Korea and 31% (27 complications in 22 patients out of total 71 cases) in China after each treatment. Conclusions: The end results of Korea series which was treated with neoadjuvant chemo- and surgical methods are better than that of non-invasive thermal ablation in china. But we also believe the HIFU, as one of, was also effective to decrease the local recurrence and symptomatic releaf for stage II or even in III of osteogenic sarcomas.

• Korean Journal of Poultry Science
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• v.37 no.1
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• pp.51-62
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• 2010

This study was conducted to investigate the effects of dietary supplementation of multiple probiotics on the performance, small intestinal microflora and immune response in laying hens and broilers. In Exp.1, a total of 800, 82 wk old Hy-line Brown$^{(R)}$ laying hens were assigned to one of the following five dietary treatment; Control, Antibiotics (avilamycin 6 ppm), Probiotics; PB-M (Micro-ferm$^{(R)}$ 0.2%), PB-L (Lacto-sacc$^{(R)}$ 0.1%), PB-Y (Y University probiotics 0.2%). Each treatment was replicated eight times with 20 birds in each replicate and two birds were housed in each cage. Twenty birds units were arranged according to completely randomized block design. Feeding trial lasted 6 wk under 16 h lighting regimen. The Exp. 2, was conducted with a total of 1,000 broilers chicks (Ross$^{(R)}$). They were divided into five treatments, same as those of Exp. 1. Birds were fed starter (0~3 wk) and grower (4~5 wk) diets. Each treatment was replicated four times with 50 birds per pen comprising of deep litter. In Exp. 1, egg production parameters, such as hen-day and hen-house egg production, egg weight, broken and soft shell egg production, feed intake and feed conversion were not significantly different among treatments. However, strength and thickness of eggshell were significantly (P<0.05) different. Among the probiotics, PB-Y showed the highest strength and thickness of eggshell. Eggshell color, egg yolk color and Haugh unit were not significantly influenced. In Exp. 2, overall weight gain (0~5 wk) and mortality were not significantly different among treatments. However, weight gain of birds from PB-Y treatment during starter (0~3 wk) was significantly lower than the birds from Control and Antibiotic treatment. During the whole period (0~5 wk), birds from Antibiotics treatment had higher feed intake and Production Index (PI) and lower feed conversion than birds from Control treatment. Probiotics treatments were not significantly different from the Control on feed intake and feed conversion. In Exp.1, there were significant (P<0.05) differences in leukocytes parameters, such as white blood cell (WBC), hetrophil (HE), lymphocytes (LY), monocyte (MO), eosinophil (EO) and stress index (SI; HE/LY) in the blood of layers. Birds from Antibiotics and probiotics treatments tended to increase these parameters. In Exp. 2, however, only SI was significantly (P<0.05) decreased in Antibiotics treatments. Concentration of serum immunoglobulin (IgG) were higher (P<0.05) in PB-M and PB-Y treatments when compared with Control treatment in Exp. 1. The population of E. coli significantly (P<0.05) decreased in birds from Antibiotics, PB-L and PB-Y treatments when compared with birds from Control treatment in Exp. 1. Metalbolizability of crude fat decreased significantly (P<0.05) in birds from probiotic treatments in Exp. 2. It was concluded that the response of probiotics on the productivity of layers and broilers were different. Probiotics increased strength and thickness of eggshell in layers, and decreased feed conversion and increased PI in broilers. Leukocytes and IgG tended to increase by supplementation of antibiotics and probiotics in layers. Intestinal E. coli tended to decrease in layers. Digestibility of crude fat of diet decreased in probiotics treatments broilers. Parameters of blood and microbial were more sensitive in layers than broilers.

• Journal of Society of Preventive Korean Medicine
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• v.5 no.2
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• pp.40-68
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• 2001

In this study, grade of subjective symptom appealed by laborer of Jeollabuk-do was evaluated using questionary regarding factor made effect on musculoskeletal disease and in addition, studied relationship with health promotion life style of them. Based on the result, relationship of general characteristics of musculoskeletal subjective symptom and life-style of the subjects was concluded as below. 1. General characteristics of study subjects were as following. Ratio of male was higher as 57.7% of male and 42.2% female and age distribution was 5.1% of 20s, 34.99% of 30s, 36.3% of 40s and 23.7% of 50s and therefore, $30{\sim}40$ aged groups showed highest ratio. Most subjects (74.9%) was married status and in case of education level, high-school graduate and dropout (23.3%) and over-college graduate (46.8%) showed highest distribution. $1{\sim}2$ Mil. KRW (29.5%) and $2{\sim}2.99$ Mil. KRW (21.2%) is the main income distribution and however there was high ratio of non-reply (29.0%). In case of employment period, $10{\sim}14$ years (15.3%) and over 15 years (29.6%) showed highest ratio and there were many non-reply (39.4%) and in addition, 67.6% replied as own house and 14.3% as lease on deposit base in question of residence type. 2. Subjects showed high ratio of subjective symptom appeal of 62.79% and many cases (50.23%) appealed 1 or 2 symptoms. Symptom by body region was 29.8% (waist), 27% (shoulder), 21.2% (knee), 15.5% (neck), 9.5% (ankle), 8.1% (wrist) and 5.0% (elbow) in order. In case of relationship with general characteristics, female comparing with male, non-residence of own house, subjects with lower education level and employment period of $10{\sim}14$ years showed higher appeal rate and kind of symptoms than others. Therefore, it was concluded that rate of musculoskeletal symptom appeal have close relationship with gender, level of living, education level, age and employment period. 3. In case of severe pain of upper body except waist and ankle, it was appealed in both or right side and it means that upper body pain is originated from right side and right region pain is transited to both region pain. In addition, there was 39.41% of non-reply to existence of right-left region pain and therefore, it was evaluated that, in may cases, there was no awareness of their own symptom condition even on subjective symptom. 4. Degree of pain was, as pain over middle level, evaluated as 2.79 on full mark of 4.0 and in order of waist (2.97), ankle (2.83), knee (2.82), wrist (2.82), neck (2.79), shoulder (2.70) and elbow (2.62). In addition, 71.97% appealed $2{\sim}3$ cases for the latest 1 week. Owing to subjective symptom, 54.95% drop into hospital or pharmacy, 10.32% made temporary retirement or absence, 7.99% transferred into more comfortable duty and $39.4{\sim}54%$ experienced one or more managing mentioned above. 5. Fulfillment of health promotion life style of subjects was evaluated on full mark of 4.0 and total score was 2.63. Average mark of each area was personal relationship (3.05), self-realization (2.92), stress management (2.63), health control (2.48), physical exercise (2.19) and nutrition management (2.19) and personal relationship was highest and physical exercise and nutrition management were lowest. As general characteristics influencing health promotion life style, gender, residence style and employment period showed significant difference. Male showed higher mark than female and showed higher mark in order of own house, others, lease on deposit base, monthly rent. Subjects with longer employment period showed higher mark with significant difference. 6. Accounting of factor influencing each area of health promotion life style, self-realization showed significance in marriage status, income, residence style and education level and health control in age, residence style and employment period. Physical exercise showed significant difference in gender, age, residence style and employment period and nutrition in gender, age, residence style and employment period. Stress management showed significant difference in residence style and employment period and however not in personal relationship. 7. Health promotion life style relating with existence and kind of pain showed significant difference in all area except personal relationship area. In absence of pain, there was statistically significant high score in all area even in total health promotion life style and all area. Accounting of kind of pain, cases of $1{\sim}2$ kinds of pain and $5{\sim}6$ kinds of pain showed relatively high score and it was lower than mark of subject stated absence of pain. 8. Subjects appeal symptom were classified by symptom region and difference of total and each areas were evaluated. General area (p=0.002), self-realization (p=0.012), health management (p=0.023), physical exercise (p=0.028), nutrition management (p=0.028) and stress control (p=0.001) showed statistically significant difference and not in personal relationship area. Especially, elbow, shoulder and neck area marked high and group appealed pain of knee, arm and elbow, foot and ankle marked low. Based on those results, subjective symptom should be accounted seriously in diagnosis of occupational musculoskeletal disease of laborer and among subjective symptom, general characteristics of gender, age, condition of living, education level and employment period make effect. Generally subject appeal symptom marked lower than subject without symptom appeal and it means that life management of subject appealing musculoskeletal pain make important role in management and treatment of occupational musculoskeletal disease.

• Radiation Oncology Journal
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• v.13 no.2
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• pp.181-189
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• 1995

Pupose: Radiation therapy(RT) is conventionally standard treatment for locally advanced stage for uterine cervix cancer. Recently to improve treatment results, combined chemotherapy and radiation therapy was tried We retrospectively analysed our experience of 122 patients. Comparision of the results in 45 patients treated with RT alone and 77 patients treated with RT plus chemotherapy was made Materials and Mathods: From January 1985 to December 1991 122 patients with cervix cancer were treated with whole pelvic external RT and ICR(34 1 ICR, 77 2 ICR, 11 high dose rate ICR) in our department. Forty five patients were treated with RT alone, and 77 patients were treated with combined RT plus chemotherapy Mean age was 58 years(range:29-81). Histologic types were 111 squamous cell carcinoma, 5 large cell carcinoma, 3 adenocarcinoma, and 2 adenosquamous cell carcinoma. According to the FIGO stage 6 had stage $IA(4.9\%),$ 11 had $IIA(9.0\%),$ 37 had $IIB(30.3\%),$ 3 had $IIIA(2.5\%),$ 63 had $IIIB(51.6\%).$ and 2 had stage $IV(1.6\%).$ In 77 patients with RT Plus chemotherapy, 36 patients were treated with VBP(vinblastin, bleomycin, cisplatinum) , 39 patients with cisplatinum plus 5-FU and 2 patients with 5-FU. Results: Complete response after external RT (3960cGy-5500cGy) was achieved in 61 patients$(50\%).$ The actuarial 5 year and 9 rear survival rate was $57.8\%\;and\;53.9\%,$ respectively. Five rear actuarial survival rate was $63.1\%$with RT alone(n=45) and $55.9\%$ with RT plus chemotherapy(n=77). The 5 rear survival rate was $35.5\%$ for 1 course of ICR and $67\%$ for 2 courses of ICR. There was statistically significant advantage of survival with RT alone group who were treated with 2 courses of ICR and dose to the A Point)=8000cGy (4/25 died). In RT plus chemotherapy group, dose response was not seen and there was no difference in 5 year survival between 1 course and 2 course of ICR $(50\%\;vs\;56.8\%),$ and dose to point A less than 8000 cGy and more than 8000 $cGy(55.6\%\;vs\;55.7\%).$ There was no significant difference in survival between RT alone and RT plus chemotherapy for patients with tumor size greater than 3cm in size. Five year survival rate for early stage (Stage IB and IIA) with RT alone group and with RT Plus chemotherapy group was $60\%\;and\;77.0\%,$ respectively In advanced stage (stage IIB, IIIA, IIIB, IVA) the 5 year actuarial survival rate were $62.6\%,$ for RT alone group vs $53.6\%$ for RT plus chemotherapy group. Conclusion: Present study demonstrates that there is no survival advantage with adding chemotherapy in advanced stage of uterine cervix cancer. RT alone is considered as treatment of choice for patients with locally advanced cervix cancer. There was increased survival in RT alone group treated with RT dose above 8000 cGy to point A and 2 course of ICR. but 2 course of ICR and RT dose above 8000 cGy to point A did not affect survival advantage in RT plus chemotherapy group.

• Asia pacific journal of information systems
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• v.20 no.4
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• pp.53-79
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• 2010

The study was originated from recognition that project participants' satisfaction should be Improved to raise project performance and to make progress of a successful project since the above dissatisfaction was operated as a danger factor of the project. The study selected one large-scale sample project and attempted measuring characteristics of the project, participants' satisfaction and project performance with the whole project participants. The study analyzed correlations between individual level (team members) and group level (development team), and examined what effect a sub project manager under complicated hierarchical organization of the large-scale project, namely PL (project leader)'s leadership style had on each individual project participant's satisfaction and what effect project uncertainty in organization/technology environment had on project participants' satisfaction and project performance. The study verified that development team (group) had an effect on team member (individual)-level project participants' satisfaction by disclosing that there was a significant dispersion among groups within project participants' satisfaction by each individual. It is analyzed that it is necessary to make improvement through approach by each pertinent team to raise individual-level project participants' satisfaction. The study also verified PL's ideal leadership under strict methodology and hierarchical control of the large-scale project. Based on the verification of the hypotheses, the results of the analysis were produced as follows. First, the development team affects the satisfaction level that an individual has when he/she participates in a project. This suggests that the satisfaction with project participation should be improved at the team level. In addition, the project management style and leadership orientation of the manager of a sub project who is mostly affected by the team proved to have a direct influence on the satisfaction with project participation and project performances. Second, both the performance-oriented leadership and the relationship-oriented leadership of the PL of the development team were verified to have a significant effect on the satisfaction of the team members associated with project participation. In other words, when the team members recognize that the PL of the development team shows both the performance-oriented leadership and the relationship-oriented leadership, their satisfaction with project participation increases accordingly. Third, it was verified that the uncertainty of the organizational environment significantly affects the satisfaction level when the PL of the development team exerts a relationship-oriented and performance-oriented leadership. The higher the uncertainty of the organizational environment is, the more the satisfaction with project participation decreases whereas the relationship-oriented leadership has a more positive effect on the satisfaction than the performance-oriented leadership style. Fourth, when the PL of the development team exerts the relationship-related and performance-related leadership, the uncertainty of the technological environment has a significant influence on the satisfaction level. The higher the uncertainty of the technological environment is, the more the satisfaction with project participation decreases whereas the performance-oriented leadership has a more positive effect on the satisfaction than the relationship-oriented leadership style. The result of the research on the uncertainty of the project environment suggests that when the development team leader exerts a relationship-oriented and performance-oriented leadership style, the uncertainty of the organizational environment has a significant effect on the satisfaction with project participation; the higher the uncertainty of the organizational environment, the more the satisfaction level decreases, and the relationship-oriented leadership style affects the satisfaction level more positively than the performance-oriented leadership style. In addition, when the development team leader displays a relationship-oriented and performance-oriented leadership style, the uncertainty of the technological environment has a significant effect on the satisfaction with project participation; the higher the uncertainty of the technological environment. the more the satisfaction level decreases. The performance-oriented leadership style as well affects the satisfaction level more positively than the relationship-oriented leadership style. Based on the above results, the research provides the following implications when handling multiple concurrent projects. First, the satisfaction with the participation in the multiple concurrent projects needs to be enhanced at the team (group) level. Second. the manager of the project team, particularly the middle managers should have both a performance-oriented and relationship (task and human)-oriented attitude and exert a consolidated leadership in order to improve the satisfaction of team members with project participation and their performances. Third, as the uncertainty factor of the technological and organizational environment among the characteristics factors of the project has room for methodological improvement depending on one's effort even though there are some complications, we need to continuously prevent and control the risks resulting from the uncertainties of the technological and organizational environment of the project in order to enhance the satisfaction of project participation and project performances. Fourth, the performance (task)-oriented leadership is required when there is uncertainty in a technological environment while the relationship (human)-oriented leadership is required when there is uncertainty in an organizational environment. This research has the following limitations. First, this research intended to select one large-sized sample project and measure the project characteristics, the satisfaction of all the participants associated with project participation, and their performances. Therefore, it is inappropriate to generalize and apply the result of this result onto other numerous projects. Second, as this case study entailed a survey to measure the characteristics factors and performance of the project, since the result value was based on the perception of project team members, the data may have insufficient objectivity. Third, though this research targeted on all the project participants, some development teams did not provide sufficient data and questionnaires were collected from some specific development teams among the 23 development teams, causing a significant deviation in the response rate among the development teams. Therefore, we need to continuously conduct the follow-up researches making comparisons among the multiple projects, and centering on the characteristics factors of the project and its satisfaction level.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.56 no.4
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• pp.404-412
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• 2011

This experiment was conducted to clarify the effect of the temperature for grain filling duration on quality and taste of cooked rice cultivated in different region in Korea. In 2006 and 2007, 4 mid-late maturing group of rice varieties (Nampyeongbyeo, Ilpumbyeo, Junambyeo and Dongjin 1) were cultivated in 28 experimental plots of 27 different regions located in 8 provinces. The taste of cooked rice were positively correlated with 1,000 grain weight but negatively correlated with protein content of brown rice. Mean temperature for 30 days from heading was more closely correlated with grain filling and tastes of cooked rice than those for 40 days. Though, the optimum mean temperature for the best taste of cooked rice for 30 days after heading was 22.1 to $23.1^{\circ}C$ depending on varieties, in general, 1,000 grain weight and cooked rice taste were the highest in the mean temperature of $22.2^{\circ}C$ for 30 days from heading. But grains were poorly ripened in case of the mean temperature lower than $21.0^{\circ}C$ for 30 days after heading. Therefore, for the better taste of cooked rice in Korea, the developing new rice varieties and cultivation method should be focused to adjust the mean temperature within $22-23^{\circ}C$ during the period of 30 days after heading.

• Applied Biological Chemistry
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• v.14 no.2
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• pp.137-148
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• 1971

Studies were carried out to investigate the main fermentation microorganisms and their flora changes during Korean native soy-sauce fermentation. Korean native Maeju loaves collected from 5 Do's were separated into surface and inner parts. Four different soy-sauces-the surface part Maeju fermented soy-sauce, the inner part, the surface and inner part combined Maeju fermented soy-sauce, and the semi-Japanese type soy-sauce were fermented and the changes of fermentation microorganism flora and the various chemical components during the period of their fermentations were studied. Besides, 14 home-made soy-sauces collected from 14 different places all over Korea were examined in comparison with the laboratory soy-sauces and to determine the characteristics of Korean native soy-sauce. The results were as follows: 1. The main microorganisms in Korean native soy-sauce fermentation were determined as; Aerobic bacteria: Bacillus subtilis, Bacillus pumilus Lactic acid bacteria: Pediococcus halophilus, Leuconostoc mesenteroides Yeasts: Torulopsis datila, Saccharomyces rouxii 2. Microflora changes during Korean native soy-sauce fermentation were as follows; Aerobic bacteria increased until the 2nd week of fermentation and then gradually decreased. The lactic acid bacteria increased until the 3rd week, after which decreased. When the lactic acid fermentation lowered the pH value to below the 5.4, yeasts were able to grow and participate the fermentation. As the production of organic acids amounted, to a certain height, the growth of all microorganisms lead to the period of decline or death at about the 2nd month of fermentation. After boiling of soy-sauce most microorganisms except a few of Bacillus sp. disappeared. Occosionally yeasts and lactic acid bacteria survived depending upon the composition of soy-sauce. 3. Changes of general chemical components influencing the microflora were investigated for the period of Korean native soy-sauce fermentation. Tetal acidity, salt concentration and total nitrogen were increasing steadily over the entire period of fermentation. pH values were dropping to a certain degree of about 4.5. Salt concentration and pH value seemed to be the important factors influencing the microflora. 4. The microflora were influenced by chemical components of soy-sauce. Aerobic bacteria were able to survive in all soy-sauce as they made spores. Growth of lactic acid bacteria was inhited at 23-26% of salt concentration and pH 4.8. Soy-sauce yeasts started to grow only at pH below 5.4 and seemed to be inhibited at around 26% of salt concentration under pH 4.5-4.7. 5. The open kettle boiling of soy-sauce, the characteristic process of Korean native soy-sauce manufacturing, was effective to sterilize microorganisms, increase the salt concentration, and coagulate proteins. 6. The average viable cell counts of microorganism found in collected samples of home-made Korean native soy-sauces were; Aerobic bacteria: $53{\times}10^2\;cell/ml$ Lactic acid bacteria: 34 cell/ml Yeasts: 14 cell/ml The average values of chemical compositions of samples of home-made Korean native soy-sauce were; Salt concentration: 28.9% pH value: 4.79 Total acidity(lactic acid): 0.91g/100ml Total nitrogen: 1.09g/100ml

• Clinical and Experimental Pediatrics
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• v.52 no.10
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• pp.1090-1102
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• 2009

Purpose:To evaluate current feeding practices and maternal nutritional knowledge on complementary feeding. Methods:Mothers of babies aged 9-15 months who visited pediatric clinics of 14 general hospitals between September and December 2008 were asked to fill questionnaires. Data from 1,078 questionnaires were analyzed. Results:Complementary food was introduced at 4-7 months in 89% of babies. Home-made rice gruel was the first complementary food in 93% cases. Spoons were used for initial feeding in 97% cases. At 6-7 months, <50% of babies were fed meat (beef, 43%). Less than 12-month-old babies were fed salty foods such as salted laver (35%) or bean-paste soup (51%) and cow's milk (11%). The following were the maternal sources of information on complementary feeding: books/magazines (58%), friends (30%), internet web sites (29%), relatives (14%), and hospitals (4%). Compared to the 1993 survey, the incidence of complementary food introduction before 4 months (0.4% vs. 21%) and initial use of commercial food (7% vs. 39%) had decreased. Moreover, spoons were increasingly used for initial feeding (97% vs. 57%). The average maternal nutritional knowledge score was 7.5/10. Less percentage of mothers agreed with the following suggestions: bottle formula weaning before 15-18 months (68%), no commercial baby drinks as complementary food (67%), considering formula (or cow's milk) better than soy milk (65%), and feeding minced meat from 6-7 months (57%). Conclusion:Complementary feeding practices have considerably improved since the last decade. Pediatricians should advise timely introduction of appropriate complementary foods and monitor diverse information sources on complementary feeding.

• Journal of Korean Society of Environmental Engineers
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• v.32 no.1
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• pp.33-46
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• 2010

We investigated and estimated at the characteristics of decomposition and by-products of N-Nitrosodimethylamine (NDMA) using a design of experiment (DOE) based on the Box-Behken design in an UV process, and also the main factors (variables) with UV intensity($X_2$) (range: $1.5{\sim}4.5\;mW/cm^2$), NDMA concentration ($X_2$) (range: 100~300 uM) and pH ($X_2$) (rang: 3~9) which consisted of 3 levels in each factor and 4 responses ($Y_1$ (% of NDMA removal), $Y_2$ (dimethylamine (DMA) reformation (uM)), $Y_3$ (dimethylformamide (DMF) reformation (uM), $Y_4$ ($NO_2$-N reformation (uM)) were set up to estimate the prediction model and the optimization conditions. The results of prediction model and optimization point using the canonical analysis in order to obtain the optimal operation conditions were $Y_1$ [% of NDMA removal] = $117+21X_1-0.3X_2-17.2X_3+{2.43X_1}^2+{0.001X_2}^2+{3.2X_3}^2-0.08X_1X_2-1.6X_1X_3-0.05X_2X_3$ ($R^2$= 96%, Adjusted $R^2$ = 88%) and 99.3% ($X_1:\;4.5\;mW/cm^2$, $X_2:\;190\;uM$, $X_3:\;3.2$), $Y_2$ [DMA conc] = $-101+18.5X_1+0.4X_2+21X_3-{3.3X_1}^2-{0.01X_2}^2-{1.5X_3}^2-0.01X_1X_2+0.07X_1X_3-0.01X_2X_3$ ($R^2$= 99.4%, 수정 $R^2$ = 95.7%) and 35.2 uM ($X_1$: 3 $mW/cm^2$, $X_2$: 220 uM, $X_3$: 6.3), $Y_3$ [DMF conc] = $-6.2+0.2X_1+0.02X_2+2X_3-0.26X_1^2-0.01X_2^2-0.2X_3^2-0.004X_1X_2+0.1X_1X_3-0.02X_2X_3$ ($R^2$= 98%, Adjusted $R^2$ = 94.4%) and 3.7 uM ($X_1:\;4.5\;$mW/cm^2$, $X_2:\;290\;uM$, $X_3:\;6.2$) and $Y_4$ [$NO_2$-N conc] = $-25+12.2X_1+0.15X_2+7.8X_3+{1.1X_1}^2+{0.001X_2}^2-{0.34X_3}^2+0.01X_1X_2+0.08X_1X_3-3.4X_2X_3$ ($R^2$= 98.5%, Adjusted $R^2$ = 95.7%) and 74.5 uM ($X_1:\;4.5\;mW/cm^2$, $X_2:\;220\;uM$, $X_3:\;3.1$). This study has demonstrated that the response surface methodology and the Box-Behnken statistical experiment design can provide statistically reliable results for decomposition and by-products of NDMA by the UV photolysis and also for determination of optimum conditions. Predictions obtained from the response functions were in good agreement with the experimental results indicating the reliability of the methodology used.

• Radiation Oncology Journal
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• v.23 no.3
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• pp.186-193
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• 2005

Purpose: To improve the management of a medical linear accelerator, the records of operational failures of a Varian CL2l00C over a ten year period were retrospectively analyzed. Materials and Methods: The failures were classified according to the involved functional subunits, with each class rated Into one of three levels depending on the operational conditions. The relationships between the failure rate and working ratio and between the failure rate and outside temperature were investigated. In addition, the average life time of the main part and the operating efficiency over the last 4 years were analyzed. Results: Among the recorded failures (total 587 failures), the most frequent failure was observed in the parts related with the collimation system, including the monitor chamber, which accounted for $20\%$ of all failures. With regard to the operational conditions, 2nd level of failures, which temporally interrupted treatments, were the most frequent. Third level of failures, which interrupted treatment for more than several hours, were mostly caused by the accelerating subunit. The number of failures was increased with number of treatments and operating time. The average life-times of the Klystron and Thyratron became shorter as the working ratio increased, and were 42 and $83\%$ of the expected values, respectively. The operating efficiency was maintained at $95\%$ or higher, but this value slightly decreased. There was no significant correlation between the number of failures and the outside temperature. Conclusion: The maintenance of detailed equipment problems and failures records over a long period of time can provide good knowledge of equipment function as well as the capability of predicting future failure. Wore rigorous equipment maintenance Is required for old medical linear accelerators for the advanced avoidance of serious failure and to improve the qualify of patient treatment.