• Journal of Radiation Protection and Research
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• v.39 no.4
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• pp.206-212
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• 2014

We report here on the results of evaluating the radiation doses using chest computed tomography (CT) for patients with pneumoconiosis complication. For the first time, we visited the 17 MIPs to evaluate the dose-length product (DLP, $mGy{\cdot}cm$), CT unit, and protocols of scanning and image reconstruction those is routinely used for treating patients with pneumoconiosis who have complication. All statistical analysis was performed using the Statistical Program for Social Sciences (SPSS ver. 19.0, Chicago, IL, USA). Mean of total DLP was $727.7mGy{\cdot}cm$, ranging from 272.0 to $1228.7mGy{\cdot}cm$. DLP from obtaining parenchymal lung images was significantly reduced than that from obtaining total lung images (555.9 vs. 707.2, p<0.001). Third quartile of total and pre-scanning DLP was 1036.1 and $504.1mGy{\cdot}cm$, respectively. Chest CT radiation doses for patients with pneumoconiosis complication are similar with korean diagnostic reference level as well as international guidelines.

• Safety and Health at Work
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• v.6 no.1
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• pp.25-29
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• 2015

Background: Shift work has been associated with occupational stress in health providers and in those working in some industrial companies. The association is not well established in the law enforcement workforce. Our objective was to examine the association between shift work and police work-related stress. Methods: The number of stressful events that occurred in the previous month and year was obtained using the Spielberger Police Stress Survey among 365 police officers aged 27-66 years. Work hours were derived from daily payroll records. A dominant shift (day, afternoon, or night) was defined for each participant as the shift with the largest percentage of total time a participant worked (starting time from 4:00 AM to 11:59 AM, from 12 PM to 7:59 PM, and from 8:00 PM to 3:59 AM for day, afternoon, and night shift, respectively) in the previous month or year. Analysis of variance and covariance were used to examine the number of total and subscale (administrative/professional pressure, physical/psychological danger, or organizational support) stressful events across the shift. Results: During the previous month and year, officers working the afternoon and night shifts reported more stressful events than day shift officers for total stress, administrative/professional pressure, and physical/psychological danger (p < 0.05). These differences were independent of age, sex, race/ethnicity, and police rank. The frequency of these stressful events did not differ significantly between officers working the afternoon and night shifts. Conclusion: Non-day shift workers may be exposed to more stressful events in this cohort. Interventions to reduce or manage police stress that are tailored by shift may be considered.

• Korean Journal of Digital Imaging in Medicine
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• v.13 no.2
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• pp.83-90
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• 2011

To prospectively determine the diagnostic performance a combination of standard bolus-chase magnetic resonance (MR) angiography and MR angiography with time-resolved imaging of contrast kinetics (TRICKS) for depicting severity of the head and neck vascular diseases. Over a period of two months, A total of 100 patients(average ages : $50{\pm}8$, male : 60, female : 40) with head and neck vascular diseases were performed on the GE excite 3.0 T units with 8-channel head coil and 4-channel NV coil. Imaging parameters for a typical study were as follow: SBC(TR/ TE/ FA/ SliceThicken./ Slab/ Freq./ FOV/ BW/Scan Time) = 5.4/ min/ 30/ 2/ zip2/ 70/ $224{\times}448$/ 30/ 62.50/ 28, TRICKS(TR/ TE/ FA/ Slice Thicken/Slab/ Freq./ FOV/ BW/ Temp Res./ Scan Time = 3.6/ min/ 25/ 4/ 30/ $160{\pm}384$, zip512/ 30/ 100/ 1 to 1.5/ 23). The analysis of all MR images, which have respect-ively classified two techniques into some diseases. The results of the former were divided into two groups(SBC, TRICKS)with 4 grading of two reader, respectively. Wilcoxon signed rank test was used to determine if a significant difference between imaging techniques existed(p < 0.05). In 33 of 100 patients, arterio-venous malformation was 11% at TRICKS, subclavian vein stenosis : 8%, fistular sinus : 4%, jugular vein stenosis:6%, Middle Cerebral Artery bypass surgery : 4%, p < 0.05). The rest of 67 patients were considered as the results of SBC(14% in the basilar artery stenosis, carotid stenosis : 16%, vertebral stenosis : 17%, central neuro-cytoma : 5%, meningioma : 5%, Not appliable : 10%, p < 0.05). Sensitivity and specificity of TRICKS MR angiography in SVS, FS, JVS, MCABS were improved compared with those at standard MR angiography. In SBS MR angiography which were improved in BAS, CS, VS, CN, Meningioma. In conclusion, TRICKS MR angiography of the SVS, FS, JVS, MCABS is superior to standard MR angiography regarding the number of diagnostic grading. The SBS MR angiography were improved in BAS, CS, VS, CN, Meningioma. and assessment of the degree of luminal narrowing on both TRICKS and SBS.

• The Journal of the Korea Contents Association
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• v.18 no.1
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• pp.623-641
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• 2018

The goal of this study is to verify the effectiveness of collective leadership. Specifically, we examine the direct effect of collective leadership on creative behavior and how this relationship is affected indirectly by organization-based self-esteem. Further, we identify the conditional indirect effect psychological safety has in moderating this mechanism. To minimize the common method bias, job rank and the affectivity in work situations were set as control variables. After excluding ten univariate outliers from 319 responses that were collected, a total of 309 samples were used for analysis. Our findings showed that collective leadership has a positive effect on the creative behavior of organization members, and that organization-based self-esteem played the role as partial mediator in the relationship between collective leadership and creative behavior. Also, the conditional indirect effect of psychological safety was found to be significant in the 'high' and 'very high' percentile levels, but not in the 'very low,' 'low,' and 'middle' levels. Together, the findings imply that when leaders at organizations promote members' organization-based self-esteem and creative behavior through collective leadership, it can be more effective when members feel high psychological safety in the organization.

• Journal of Korean Society of Environmental Engineers
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• v.22 no.4
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• pp.699-712
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• 2000

Juam lake is a major water resource for the industrial and agricultural activities as well as the resident life of Kwangju and Chonnam regions. However, the water quality of the lake is getting worse due to a large quantity of pollutant inflowing to the lake. Thus, the strategy for achieving the water quality goal of the lake should be developed as soon as possible. When there are various alternatives that can be used as the strategy, several criteria based on the achievement degree of water quality goal, the applicability of technique and social environment, and the reasonableness of the cost required are made to evaluate and rank the alternatives. However, it is difficult to make a decision when there are multiple criteria and conflicting objectives and specifically the estimated values of criteria contain elements of uncertainty. The uncertainty stems from the lack of available information, the randomness of future situation, and the incomplete knowledge of expert. As the degree of uncertainty is higher, the decision becomes more difficult. In this study, a fuzzy decision-making method is presented to assist decision makers in evaluating various alternatives under uncertainty. The method allows decision makers to characterize the associated uncertainty by applying fuzzy theory and incorporate the uncertainty directly into the decision making process for selecting the "best" alternative so decisions can be made that are more appropriate and realistic than those made without taking uncertainty in account.

• Restorative Dentistry and Endodontics
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• v.27 no.3
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• pp.249-256
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• 2002

The use of flowable composite resins as liners in class II packable composite restoration has been suggested by some manufacturers. However, the contributions of this technique are unproven. The purpose of this study was to compare the gingival microleakage in class II packable composite restorations with or without the use of flowable composite resins as liners. Slot cavities were prepared on both proximals of 80 extracted human molars and randomly assigned to 8 groups of 20 each. The gingival margins were located at 1mm above CEJ in 80 cavities (group1-4) and 1mm below CEJ in 80 cavities (group5-8). The prepared teeth were mounted in the customized tray with adjacent teeth to simulate clinical conditions and metallic matrix band (Sectional matrix) and wooden wedges were applied. After acid etching and application of Single Bond, each group was restored with the following materials using incremental placement technique: Group 1,5 (Filtek P60), group 2, 3, 4 and group 6, 7, 8 (AeliteFlo, TetricFlow, Revolution/ Filtek P60). All specimens were thermocycled 500 times between 5$^{\circ}C$ and 55$^{\circ}C$ with 1 mimute dwell time, immersed 2% methylene blue dye for 24 hours and then rinsed with tab water. The specimens were embedded in clear resin and sectioned longitudinally through the center of restoration with a low speed diamond saw. Dye penetration at gingival margin was viewed at 20 magnification and analyzed on a scale of 0 to 4. Kruscal-Wallis One way analysis and Mann-Whitney Rank sum test were used to analyze the results. The results of this study were as follows. 1. The leakage values seen at the enamel margin were significantly lower than those seen at the dentin margin(P<0.05). 2. On the enamel margin, packable composite resins with flowable liners showed lower leakage than those without flowable liners, but there were no significant differences among the four groups(P>0.05). 3. On the dentin margin, four groups demonstrated moderate to severe leakage, and there were no significant differences in leakage values(P>0.05).

• Journal of the Ergonomics Society of Korea
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• v.26 no.3
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• pp.91-100
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• 2007

The purposes of this research are to survey work-related risk factors of musculoskeletal disorders(MSDs) in various departments and tasks at general hospitals in non-manufacturing sectors, and to use basic data derived from the survey results in preventing work-related MSDs in hospital workers. Investigation started in March of 2006 and continued for 6 months in 220 general hospitals at Seoul, Incheon, Kyeongi, and Kangwon area. Investigators visited and interviewed workers in hospitals to identify the presence of tasks of musculoskeletal burden, the investigation results of ergonomic risk factors required by the Occupational Safety and Health Law, statistical analysis from questionnaire for musculoskeletal symptoms, and major departments and tasks that have such risk factors. Twenty-seven percents of hospitals finished the investigation of ergonomic risk factors, and 69% did not do the investigation while remained 4% did not have such factors in their hospitals. The rank order of major departments that had such musculoskeletal burdens was kitchen rooms of 143, managing departments/computer rooms/dispensaries of 137, physical treatment rooms of 109, nursing departments of 96, radiological and clinical laboratories of 63. Eighteen hospitals that did not hold legal duties by the section 148 of labor minister decree practiced prevention programs of MSDs according to the labor-management cooperation. Nursing departments ranked in the first place for the numbers of musculoskeletal symptoms of 438. Managing departments/computer rooms/dispensaries, kitchen rooms, and medical treatment departments held 127, 52 and 45 symptoms, respectively. The magnitude order of physical symptom areas followed shoulder of 185, backs and waist of 166, hand wrists of 120, necks of 110, and legs/feet of 106. The departments and jobs that had major work-related ergonomic risks were patient transporting, central supplying, patient nursing (moving patients into wheel-chairs, changing of patient posture and sheet alteration), manual transporting, operation, and managing/computer departments.

• Journal of Korea Water Resources Association
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• v.46 no.10
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• pp.977-987
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• 2013

This study aims to develop a multiple criteria decision making (MCDM) approach for flood vulnerability assessment which considers uncertainty. The flood vulnerability assessment procedure consists of three steps: (1) use the Delphi process to determine the criteria and their corresponding weights-the adopted criteria represent the social, economic, and environmental circumstances related to floods, (2) construct a fuzzy data matrix for the flood vulnerability criteria using fuzzification and standardization, and (3) set priorities based on the number of assessed vulnerabilities. This study uses a modified fuzzy TOPSIS method based on ${\alpha}$-level sets which considers various uncertainties related to weight derivation and crisp data aggregation. Further, Spearman's rank correlation analysis is used to compare the rankings obtained using the proposed method with those obtained using fuzzy TOPSIS with fuzzy data, TOPSIS, and WSM methods with crisp data. The fuzzy TOPSIS method based on ${\alpha}$-cut level sets is found to have a higher correlation rate than the other methods, and thus, it can reduce the difference of the rankings which uses crisp and fuzzy data. Thus, the proposed flood vulnerability assessment method can effectively support flood management policies.

• Journal of Gastric Cancer
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• v.1 no.2
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• pp.77-82
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• 2001

Purpose: The most important prognostic factors in gastric cancer are depth of invasion and lymph node metastasis. Therefore, the prognosis for serosa and lymph node negative gastric cancer is favorable. However, there is no general agreement on the prognostic factors in this subset of patients. This study was undertaken to evaluate the prognostic significances of venous invasion (VI), lymphatic invasion (LI), and perineural invasion (NI) in T1 and T2 gastric cancer without lymph node involvement. Materials and Methods: We retrospectively evaluated 206 patients with T1 and T2, lymph node negative gastric cancer who underwent a curative resection from 1989 to 1993 at Kangnam St. Mary's Hospital, Seoul, Korea. The Chi-square test was used to determine the statistical significance of differences, and the Kaplan-Meier method was used to calculate survival rates. Significant differences in the survival rates were assessed using the log-rank test, and the Cox regression method was used to evaluate independent prognostic significance. Results: The rate of VI, LI and NI correlated well with the depth of tumor invasion. The rates of VI (+) for T1 vs T2 was $0\%\;vs\;5.1\%$, of LI (+) was $5.6\%\;vs\;26.8\%$, and of NI (+) was $1.6\%\;vs\;26.8\%$ in NI (+). There were 13 recurrent cases, 10 cases out of the 13 were T2 gastric cancers, and the recurrence rate was higher in LI (+) and NI (+) cases than in LI (-) and NI (-) cases. The 5-year survival rates were $93.4\%$ in LI (-) cases, $77.4\%$ in LI (+) cases, $92.5\%$ in NI (-) cases, $74\%$ in NI(+) cases, $95.9\%$ in LI (-) NI (-) cases, and $73.9\%$ in LI (+) NI (+) cases. Multivariate analysis demonstrated that simultaneous LI and NI was the only significant factor influencing the prognosis. Conclusion: These results suggest that simultaneous lymphatic and perineural invasion may be an independent prognostic factor in patients with T1 and T2 gastric cancer without lymph node metastasis.

• Journal of Gastric Cancer
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• v.17 no.3
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• pp.228-236
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• 2017

Purpose: Enolase is a cytoplasmic enzyme that catalyzes the conversion of 2-phosphoglycerate to phosphoenolpyruvate in the glycolytic pathway. The aim of this study was to investigate whether the overexpression of neuron-specific enolase (NSE) can serve as a prognostic factor in patients with gastric cancer (GC). Materials and Methods: To assess its prognostic value in GC, NSE expression was measured by immunohistochemistry in a clinically annotated tissue microarray comprising of 327 human GC specimens. Cytoplasmic NSE expression was scored from 0 to 4, reflecting the percentage of NSE-positive cells. Results: In terms of histology as per the World Health Organization criteria (P=0.34), there were no differences between the NSE overexpression (NSE-OE) and NSE underexpression (NSE-UE) groups. The NSE-OE group showed a significantly lower rate of advanced GC (P<0.01), lymph node metastasis (P=0.01), advanced stage group (P<0.01), cancer-related death (P<0.01), and cancer recurrence (P<0.01). Additionally, a Kaplan-Meier survival analysis revealed that the NSE-OE group had longer cumulative survival times than the NSE-UE group (log-rank test, P<0.01). However, there were no significant differences in the serum levels of NSE expression in patients with GC and healthy volunteers (P=0.28). Conclusions: Patients with NSE overexpressing GC tissues showed better prognostic results, implying that NSE could be a candidate biomarker of GC.