• Proceedings of the Korean Radioactive Waste Society Conference
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• 2010.10a
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• pp.419-420
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• 2010

• Proceedings of the Korean Society of Plant Biotechnology Conference
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• 2003.04a
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• pp.119-119
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• 2003

• Proceedings of the Korean Society of Plant Biotechnology Conference
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• 2003.04a
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• pp.118-118
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• 2003

• Applied Biological Chemistry
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• v.41 no.4
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• pp.273-274
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• 1998

In vitro cytotoxicity of sambutoxin was measured by using various human and murine tumor cells and $IC_{50}$ values of sambutoxin ranged from 46.2 to 1,425.6 ng/ml.

• Archives of Pharmacal Research
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• v.18 no.1
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• pp.48-50
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• 1995

The $^1H NMR singls of three 6{\alpha}-bromopenicillanates$ have been assigned and the Nuclear Overthauser Effect(NOE) study of these compounds was undertaken.

• Journal of Technologic Dentistry
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• v.33 no.1
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• pp.93-102
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• 2011

Purpose: The study aimed to evaluate working environment for dental technician by measuring dust level, ventilation conditions and the use of personal protective equipment and to provide basic information required to improve working environment and develop health education programs for dental technician. Methods: A total of 240 dental technician who are registered with the Daegu Association of Dental technician and working at 34 dental laboratories participated in the study. And the dust level was measured at 21 different spots in 16 dental laboratories out of 34. Results: Of 34 dental laboratories, 31 (91.2%) were equipped with a ventilator, but the remaining 3 (8.8%) did not have a ventilator. By the number of ventilator, 1 to 3 ventilators were found in 22 dental laboratories (71.0%), 4 to 6 ventilators were in 7 laboratories (22.5%) and more than 7 ventilators in 2 laboratories(6.5%). According to the frequence of changing filters in dust collector, 20 dental laboratories (58.9%) changed filters every four weeks, 10 laboratories (29.4%) changed them every six weeks and 4 laboratories (11.7%) changed them every eight weeks. Of total respondents, 114 (61.3%) said they wore a mask all the time while working, 56 (29.6%) said they frequently wore a mask, 19 (10.1%) said they did not wear a mask. As for the type of masks, 159 (84.1%) used a disposable mask, 25 (13.2%) used a cotton mask and 5 (2.7%) used an anti-dust mask. For dust sat on their outfits while working, 102 (54.0%) shook their uniforms inside workplace to keep dust off the uniforms, 64 (33.9%) did not anything until they wash their uniforms and 23 (12.1%) shook their uniforms outside workplace to keep dust off the uniforms. Of total respondents, 182 (96.3%) had a particle in their eyes while carrying out grinding work. Based on the measurement of floating dust at workplace, 3 dental laboratories showed dust concentration exceeding the minimum level of 10 mg/$m^3$ allowed under the permit for environment. Of those, 1 laboratory had the dust concentration that was more than 1.5 times higher than the minimum level. Dust concentration was higher in laboratories that used a dust collector with 0.5 horse power and changed filters more than 3 weeks ago. Dust comprised of nickel (more than 70%), chrome (9%) and others. The mean chrome concentration was more than twice higher than the minimum permissible level of 0.5 mg/$m^3$. There were two laboratories that showed chrome concentration exceeding the level of 0.4 mg/$m^3$. Like dust concentration, chrome level was higher in laboratories that used a dust collector with 0.5 horse power and changed filters more than 3 weeks ago. There were six laboratories that had nickel concentration exceeding the minimum permissible level of 1 mg/$m^3$. Of those, one laboratory had nickel concentration that was more than three times higher than the minimum permissible level. Nickel concentration was also higher in laboratories that used a dust collector with 0.5 horse power and changed filters more than 3 weeks ago. Conclusion: It is not likely that heavy metal concentrations found in the study constitute respiratory dust. It is however necessary for health of dental technician to apply the Industrial Safety and Healthy Law to dental laboratories and make recommendations for the use of personal protective equipment, installation of a proper number of ventilators, more frequent change of filters in dust collector and improved ventilation for polishing work. At the same time, dental technician need education on how to use personal protective equipment and how to efficiently remove dust from their uniforms.

• The Journal of Korean Academy of Prosthodontics
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• v.33 no.2
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• pp.358-394
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• 1995

The author studied the actual conditions on the production of dental prosthesis made in laboratories, and also studied interrelationships between dentists and laboratory technicians in both personal and technical aspects. Two hundred-eighty four technicians, work in dental laboratories presently, were surveyed via mail and direct contact during the period from June 1 to June 30 and August 27 to August 28 in 1994 respectively. The obtained results were as follows : 1. Among the respondents, 90.5% we re working in commercial dental laboratories and their laboratories were mainly located in the Seoul area(40.9%, P<0.05). The numbers of employees in these laboratories were less than 10 persons(70.0%, P<0.01), and 75.9% of these laboratories have been in operation less than 15 years. 2. Most laboratory procedures were accomplished according to established disciplines. However, procedures such as die trimming in fixed restorations and the qualifications of the people designing removable partial dentures were not. Other problem areas were boxing of the working cast, the person determining the posterior palatal seal area, selection and arrangement of artificial teeth, occlusion rim correction and laboratory remounting of the processed denture in complete denture restorations. 3. Only half of the requesting dentists could send work authorizations to the laboratories with their work and even so, its contents were quite lacking. Consequently, there must be some standards in writing work authorization. 4. Technicians most desired clean and accurate impressions in fixed and removable dentures, and enough tooth reduction in porcelain fused to metal restorations. 5. For the establishment of better relationships between dentist and dental technician, the respondents desired the establishment of equal footing first(33.5%), and frequent conversations and muture understanding second(25.9%).

• The Korean journal of internal medicine
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• v.33 no.6
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• pp.1119-1128
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• 2018

Background/Aims: In multicenter clinical trials, laboratory tests are performed in the laboratory of each center, mostly using different measuring methodologies. The purpose of this study was to evaluate coefficients of variation (CVs) of laboratory results produced by various measuring methods and to determine whether mathematical data adjustment could achieve harmonization between the methods. Methods: We chose 10 clinical laboratories, including Green Cross Laboratories (GC Labs), the central laboratory, for the measurement of total cholesterol, high density lipoprotein cholesterol (HDL-C), low density lipoprotein cholesterol (LDL-C), serum triglycerides, creatinine, and glucose. The serum panels made with patient samples referred to GC Labs were sent to the other laboratories. Twenty serum samples for each analyte were prepared, sent frozen, and analyzed by each participating laboratory. Results: All methods used by participating laboratories for the six analytes had traceability by reference materials and methods. When the results from the nine laboratories were compared with those from GC Labs, the mean CVs for total cholesterol, HDL-C, LDL-C, and glucose analyzed using the same method were 1.7%, 3.7%, 4.3%, and 1.7%, respectively; and those for triglycerides and creatinine analyzed using two different methods were 4.5% and 4.48%, respectively. After adjusting data using Deming regression, the mean CV were 0.7%, 1.4%, 1.8%, 1.4%, 1.6%, and 0.8% for total cholesterol, HDL-C, LDL-C, triglyceride, creatinine, and glucose, respectively. Conclusions: We found that more comparable results can be produced by laboratory data harmonization using commutable samples. Therefore, harmonization efforts should be undertaken in multicenter trials for accurate data analysis (CRIS number; KCT0001235).

• Journal of Technologic Dentistry
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• v.16 no.1
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• pp.57-77
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• 1994

The purpose of this study is to investigate the extent to which dental laboratories use proper materials, procedures, devices, and equipments to fabricate crown & bridge, PFM(Porcelain Fused to Metal) crown & bridge, partial denture, complete denture, and other prosteses. 100 laboratories in Seoul were selected for this investigation. Questionnaires were constructed focusing on five topocs:crown & bridge, PFM crown & bridge, partial denture, complete denture, and other prostheses. The results from this survey were as follows : 1. Most dental laboratories used old, inexpensive, and familiar materials rather than newly developed ones. 2. Most of the dental technicians did not stick to the standard procedures of handling materials, but to their own experiences. 3. Newly developed equipments to fabricate dental prostheses were possessed by nearly 30% dental laboratories. 4. About 80% of dental laboratories were using the procedures they had learned in the school : die trimming for accurate crown margin and softening heat treatment after RPD gold casting. But less than 30% of laboratories were shown to follow the boxing procedure to produce master cast and laboratory remounting in the process of complete denture. The findings show that dental laboratory procedures to fabricate dental prostheses are incomplete and inaccurate in some instances. So, further studies are neededs to clarify the causes of some inaccurate procedures, the better and more equipments should be supplied to produce the more accurate dental posthesis, and more efforts at enancing the appropriate use of dental materials and procedures should be made.

• Journal of Technologic Dentistry
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• v.32 no.3
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• pp.221-232
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• 2010

Purpose: It is necessary for dental technicians exposed to hazardous chemicals in the dental laboratories to be informed of the various harmful effects of chemicals for their health and safety. The purposes of this study was to investigate the actual condition of the use of MSDS in dental laboratories and the recognition rate of MSDS for dental technicians. Methods: 231 dental technicians who were self-written questionnaire. The results were analyzed by SPSS 12.0. The answers to the questionnaire underwent frequency analysis, chi-square test and correlation analysis were performed to investigate association between health effects and recognition rate of chemical information. Results: The results from the effects of damage caused by chemicals 60.7%, and when it was less than 2 years working experience 47.6%. Currently any dental laboratories(rooms) was not furnished MSDS(0%) and even similar data furnishing rate was only 17.3%. Answer rate of 'Do not know about MSDS' was 73.6%. In addition to, education in the types and characteristics of chemicals(74.5%) does not receive all the higher education. For the question of 'To prevent human risks and accidents, is to provide chemical information needed', the answer rate of 'needed' was 87.2%. Moreover, the answer rate of 'To provide chemical information that could prevent accidents' was 76.6%. Therefore it was found that dental technicians need to be provided for chemical information. In addition, they wanted to get education related to chemicals used in the workplace(80.5%), and 90.9% was answered that they was willing to keep MSDS in they workplace. Conclusion: This study investigated the current dental laboratories(rooms) and the MSDS for the awareness and recognition of workers was very low, education was not being conducted properly. The dental laboratories(rooms) of the compact characteristics of the MSDS was not reasonably accessible and the furnishing location, dental laboratories(rooms) for the real item was needed for improvement. MSDS for dental technicians through education and promotion of information about chemicals and chemicals was to prevent health problems caused by the MSDS that will raise awareness of the necessity.