• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.31 no.4
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• pp.317-330
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• 2021

Objectives: By law, companies in Korea must periodically measure workers' exposure to harmful chemicals (the system is called the Work Environment Monitoring Program (WMP)[a]) and report the results to the government. The government also measures exposure to monitor the WMP's reliability (called Reliability Assessment (RA) for WMP[b]). The issue is that measured data from these two sources are so different that the objectivity of WMP needs to be confirmed by comparing the results using the European Centre for Ecotoxicology and Toxicology of Chemicals' Targeted Risk Assessment (ECETOC TRA). Methods: Step 1: Data collection from WMP reports submitted by companies (n=586) and RA for WMP written by the government (n=33). Step 2: Data Standardization by key information included. Step 3: Data conversion to input-variables required to run the ECETOC TRA model, and run the model with specific data (n=514) which meet the predetermined exposure scenario. Step 4: Statistical data analysis by process category (PROC) and ventilation type from each source ([A] and [B]). Step 5: Additional analysis of any unexpected results. Results: The process categories of the production and handling of Dichloromethane were classified into 12 PROCs, and ten of them were selected to run ECETOC TRA. Modeled values tended to be higher than measured values from both sources. For the measured values from WMP, RCR distribution by PROC was narrow (0.197-0.267, 95% CI) and did not have a relationship with ventilation type, which differs from the tendency of the modeling result. Meanwhile, the measured values from RA for WMP were relatively widely distributed (0.301-1.177, 95% CI) by PROC. In particular PROCs (13,19) were high enough to exceed 1. Also, they become low with better ventilation types and appear differently depending on the ventilation type, similar to the model result. Conclusions: This study revealed that ECETOC TRA might have the potential to serve as a screening tool for exposure assessment and to be used as assistive method for WMP to estimate exposure. Further empirical study is required to confirm its availability as a screening tool.

• Journal of the Korean Dietetic Association
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• v.11 no.2
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• pp.179-189
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• 2005

The purpose of the study was to investigate the relationships between dietitian’s job satisfaction and perception of barriers to HACCP implementation and food safety/sanitation management performance in school food service. An e-mail survey was conducted to 144 dietitians in Gyeongbuk Province. A response rate was 57.6%(N=83) and data were analyzed using SPSS Windows(ver. 10.0). Dietitians were more satisfied with ‘supervision’ and 'co-workers' than 'pay' and 'promotion.' Dietitians perceived 'lack of teachers' support on student education' and ‘limited availability of facilities/equipment' as the biggest challenges in implementing a HACCP system. A total score of sanitation/safety management performance evaluated by school districts was 92 out of 100. By category, 'safety management' and 'personal hygiene' were rated the highest whereas 'facilities/equipment' and 'HACCP system' categories were rated the lowest. The food sanitation/safety management performance scores were not correlated to dietitian’s job satisfaction, but significantly correlated to dietitian’s perceptions of barriers to HACCP implementation. As dietitians perceived facilities/equipment-related barriers greater, the scores of 'facilities/equipment(p<.01),' 'production process(p<.05),' and 'total score(p<.01)' were significantly lower. The findings suggest that more investment on facilities/equipment are needed for food safety improvement and successful HACCP implementation in school food service. Proper facilities and equipment will make employees monitor CCPs and take corrective actions more easily.

• Plant Biotechnology Reports
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• v.5 no.2
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• pp.147-156
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• 2011

Efficient Agrobacterium-mediated genetic transformation of Scoparia dulcis L. was developed using Agrobacterium tumefaciens strain LBA4404 harboring the binary vector pCAMBIA1301 with ${\beta}$-glucuronidase (GUS) (uidA) and hygromycin phosphotransferase (hpt) genes. Two-day precultured leaf segments of in vitro shoot culture were found to be suitable for cocultivation with the Agrobacterium strain, and acetosyringone was able to promote the transformation process. After selection on shoot organogenesis medium with appropriate concentrations of hygromycin and carbenicillin, adventitious shoots were developed on elongation medium by twice subculturing under the same selection scheme. The elongated hygromycin-resistant shoots were subsequently rooted on the MS medium supplemented with $1mg\;l^{-1}$ indole-3-butyric acid and $15mg\;l^{-1}$ hygromycin. Successful transformation was confirmed by PCR analysis using uidA- and hpt-specific primers and monitored by histochemical assay for ${\beta}$-GUS activity during shoot organogenesis. Integration of hpt gene into the genome of transgenic plants was also verified by Southern blot analysis. High transformation efficiency at a rate of 54.6% with an average of $3.9{\pm}0.39$ transgenic plantlets per explant was achieved in the present transformation system. It took only 2-3 months from seed germination to positive transformants transplanted to soil. Therefore, an efficient and fast genetic transformation system was developed for S. dulcis using an Agrobacterium-mediated approach and plant regeneration via shoot organogenesis, which provides a useful platform for future genetic engineering studies in this medicinally important plant.

• YAKHAK HOEJI
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• v.51 no.4
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• pp.285-290
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• 2007

The oxidative stress causes many diseases like cancer, aging, cardiovascular disease, degenerative neurological disorders (Parkinson’s disease, and Alzheimer's disease) by damage of cell membrane, protein deformation, and damage of DNA due to the oxidation of lipid of cell membrane, protein of tissue or enzyme, carbohydrate, and DNA. It is caused by the reactive oxygen species (ROS) that is produced in the metabolic process of oxygen in cell. The superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) in cell systemize the antioxidative enzymes to control the oxidative stress. In this research, it is measured that the survival rate of cell by the typical isoflavonoid of daidzein or genistein, activity of antioxidative enzyme, and ROS level, in order to study the effect of isoflavonoid over the ROS production in cell and antioxidative system. As the similar action of the isoflavonoid with the estrogen is examined, women are encouraged to get bean. In view of this trend, it is very important to find out a combination medicine that lowers the oxidative stress caused by the daidzein in the ovarian cell. In the combined treatment of the typical antioxidant of vitamin C to oxidative stress which induced by daidzein recover the control level particularly lowering the ROS in cell by 30%. However, it made no effect in the combined treatment with genistein. Therefore, the research took the combination effect of daidzein with vitamin C in order to check it effect over the antioxidative system. In conclusion, it was disclosed that the oxidative stress caused by daidzein is related to the lowering activity of SOD, and the specific combination effect of daidzein with vitamin C is related to the recovery of SOD activity.

• KSBB Journal
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• v.7 no.2
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• pp.139-143
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• 1992

One of the objectives of this work is to obtain information relevant to the industrial production of alcohol from sugar. The fermentation of alcohol by a strain of saccharomycess cerevisiae ATCC 24858 was studied In a continuous single-stage process with recycle of the cells via tangential flow microfiltration membranes. The experimental results reported in this study pertain to continuous cultures with total cell-recycle by varying the dilution rate (D=0.3, 0.5, and 0.7 $hr^{-1}$) and glucose concentration (50, 100, 150, and 200g/l sugar solution). Productivity using a repeated cell recycle system was found extremely high, 1.e., over 10 to 29 times higher than that of a smile batch system. When a sugar concentration of 200g/1 at dilution rate, 0.7 hr-1 was used, 83.9g/l ethanol was formed with an ethanol yield of 0.42(82% of theoretical) based on sugars utilized.

• Journal of the Korean Society of Industry Convergence
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• v.9 no.1
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• pp.61-66
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• 2006

In perspective of saving natural resource and energy, today's automobiles are in process of regenerating by smaller and lighter. In order to achieve the sufficiency on the consumption of the fuel, new mechanism and new assembly are required. Therefore the expectations on the new materials are very high. Especially, AI materials are widely used to reduce the weight. AI that is used in automobiles is mostly casting material, and according to the innovation of technique is in rapid development. AI Die casting is an important field as today's trend of lightweight on automobiles. One of the parts in steering system, Valve Housing plays a role of reduce the operating effort of drivers. Unfortunately, the Valve Housing which is widely reliable to the most automobiles are not developed at this moment in our automobile industry. Therefore, they are produced by casting method which cost three times or even more expensive in production. If Valve Housing, which is a part of steering system is produced by Gravity Casting, the space that manufacturing equipment will be increased, and more time and workers would be brought into service. For such reason, Die Casting would replace Gravity Casting in order to minimize cost of time, manpower, and working space.

• The Journal of Fisheries Business Administration
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• v.38 no.3
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• pp.67-88
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• 2007

This study is to estimate the factor weights for a successful sea-ranching project using the Analytical Hierarchy Process. Furthermore, it investigates the policy implications revealed by the differences in group opinions throughout fishermen, government officials, researchers and the scholars when the weights are assessed. The hierarchy is constructed for the 3 levels of factors which must be evaluated for a successful sea-ranching project. The top level of factors is divided by the ecological factors and the socioeconomic factors. As the middle level of factors, there are 3 factors such as the choice of fish, the habitat environment and the production technology under the ecological factors and another 3 factors such as the stability of fishery society, economic factors, and the law & system under the socio-economic factors. And then, at the bottom level of the hierarchy, the economic factors have two different sub-factors such as the fishing revenue and cost. The law & system has also 3 sub-factors such as the accessibility to sea-ranching area, fishing method, and surveillance. The fishermen and government officials show us quite opposite tendencies in assessments of the weights while both the researchers and scholars reveal almost the same opinions positioned at somewhere between first two groups. The study also reports the evaluations of efficiency measures for resource recovery methods among the sea-ranching project, artificial reef, release of fish seeds, and marine protection area. Both the sea-ranching project and marine protection area have the same efficiency in terms of resource recovery while the artificial reef and release of fish seeds are revealed as somewhat less efficient methods comparing to the former two methods.

• The Journal of the Korea Contents Association
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• v.14 no.11
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• pp.370-377
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• 2014

At present trend 3D Printing technology has been using more efficiently than conventional subtractive manufacturing method in various medical fields, in particular this technology superior in saving production time, cost and process than conventional. Especially in orthopedics, an attractive attention has been paid by adopting this technology because of improving operation, operation accuracy, and reducing the patient's pain. Though 3D printing technology has enormous applications still in some hospitals have not been using due to having the problem of technical utilization of hardware, software & chiefly financial availability and etc. In order to solve these problems by reducing the cost and time, we have used CT images in pre-operative planning by directly making the pelvic fracture model with open source DICOM viewer and STL file conversion program, assembly 3D printer of FDM wire additive manufacturing. After having the customized bone model of six patients who underwent unstable pelvic fracture surgery, we have operated our system in orthopedic section of University Hospital through the clinician. Later, we have received better reviews and comments on utilization availability, results, and precision and now our system considered to be useful in surgical planning.

• BMB Reports
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• v.45 no.2
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• pp.59-70
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• 2012

Carbon catabolite repression (CCR) is a key regulatory system found in most microorganisms that ensures preferential utilization of energy-efficient carbon sources. CCR helps microorganisms obtain a proper balance between their metabolic capacity and the maximum sugar uptake capability. It also constrains the deregulated utilization of a preferred cognate substrate, enabling microorganisms to survive and dominate in natural environments. On the other side of the same coin lies the tenacious bottleneck in microbial production of bioproducts that employs a combination of carbon sources in varied proportion, such as lignocellulose-derived sugar mixtures. Preferential sugar uptake combined with the transcriptional and/or enzymatic exclusion of less preferred sugars turns out one of the major barriers in increasing the yield and productivity of fermentation process. Accumulation of the unused substrate also complicates the downstream processes used to extract the desired product. To overcome this difficulty and to develop tailor-made strains for specific metabolic engineering goals, quantitative and systemic understanding of the molecular interaction map behind CCR is a prerequisite. Here we comparatively review the universal and strain-specific features of CCR circuitry and discuss the recent efforts in developing synthetic cell factories devoid of CCR particularly for lignocellulose-based biorefinery.

• Transactions of the Korean Society of Automotive Engineers
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• v.21 no.3
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• pp.88-97
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• 2013

This paper presents a robust air-to-fuel ratio (AFR) control algorithm for managing exhaust gas recirculation (EGR) systems. In order to handle production tolerance, deterioration and parameter-varying characteristics of the EGR system, quantitative feedback theory (QFT) is applied for designing the robust AFR control algorithm. A plant model of EGR system is approximated by the first order transfer function plus time-delay (FOPTD) model. EGR valve position and AFR of exhaust gas are used as input/output variables of the plant model. Through engine experiments, parameter uncertainty of the plant model is identified in a fixed engine operating point. Requirement specifications of robust stability and reference tracking performance are defined and these are fulfilled by the following steps: during loop shaping process, a PID controller is designed by using a nominal loop transmission function represented on Nichols chart. Then, the frequency response of closed-loop transfer function is used for designing a prefilter. It is validated that the proposed QFT-based AFR control algorithm successfully satisfy the requirements through experiments of various engine operating points.