• Journal of the Society of Naval Architects of Korea
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• v.49 no.5
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• pp.367-375
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• 2012

In this study, hull form of main vessel of Korean large purse seiner fishing industry is developed for the improvement of resistance performance as well as for the satisfaction to the Standard of Fishing Convention, ILO. Through the modification of reference hull form parameters and local characteristics, the hull form development is carried out. The optimum hull form parameters are searched by Sequential Quadratic Programing(SQP) method with the power estimation method of Holtrop & Mannen. To minimize the wave resistance, bulbous bow parameters are determined by the bulbous bow design method of Alvarino. The plasmatic curve is redesigned from that of the reference hull by using Lackenby method. The resistance performances of the reference and designed hull forms are estimated by using numerical simulation method. Also, the judgment of seakeeping ability and the estimation of intact stability for the designed hull form is carried out. As a result, the optimum hull form is proposed. To verify the improvement of resistance performance, model tests are carried out in towing tank. The results show that the resistance of the designed hull form is about 14% smaller than that of the reference hull from at design speed. A new hull form proposed in this study can contribute to the development of the main vessel hull form of Korean large purse seiner fishing system.

• Korean Journal of Social Welfare
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• v.45
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• pp.7-39
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• 2001

This paper examines the effect of active labor market policy on the unemployment rates in 8 welfare states. This paper focuses on the following questions: what are the major predictors of the changes in unemployment rates?; and what is the effect of active labor market policy in reducing unemployment rates? Using the data from Comparative Welfare States Data Set by Stephens (1997), Key Indicators of the Labour Market by ILO (1999) and Social Expenditure Database by OECD (1999), this paper attempts to answer the above research questions. Fuller-Battese model, a data analysis method in pooled cross-sectional time-series analysis, is adopted to identify variables predicting changes in unemployment rates. This paper analyzes the predictors by using 3 analysis models about 2 types of unemployment (overall unemployment and long term unemployment). Results are as follows: (1) economic variable such as changes in GDP has a positive effect in reducing unemployment rates; (2) active labor market policy has a positive effect in reducing unemployment rates as well; (3) job brokering service among 3 major active labor market programs has a positive effect in reducing unemployment rates; and (4) there is an interaction effect between unemployment benefit level and active labor market policy in reducing unemployment rates. Through the empirical analysis, this paper provides valuable knowledge about effects of active labor market policy on unemployment in 8 welfare states and discusses implications for the active labor market policy in Korea.

• Molecules and Cells
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• v.37 no.4
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• pp.345-355
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• 2014

Mitigating secondary delayed neuronal injury has been a therapeutic strategy for minimizing neurological symptoms after several types of brain injury. Interestingly, secondary neuronal loss appeared to be closely related to functional loss and/or death of astrocytes. In the brain damage induced by agonists of two glutamate receptors, N-ethyl-D-aspartic acid (NMDA) and kainic acid (KA), NMDA induced neuronal death within 3 h, but did not increase further thereafter. However, in the KA-injected brain, neuronal death was not obviously detectable even at injection sites at 3 h, but extensively increased to encompass the entire hemisphere at 7 days. Brain inflammation, a possible cause of secondary neuronal damage, showed little differences between the two models. Importantly, however, astrocyte behavior was completely different. In the NMDA-injected cortex, the loss of glial fibrillary acidic protein-expressing ($GFAP^+$) astrocytes was confined to the injection site until 7 days after the injection, and astrocytes around the damage sites showed extensive gliosis and appeared to isolate the damage sites. In contrast, in the KA-injected brain, $GFAP^+$ astrocytes, like neurons, slowly, but progressively, disappeared across the entire hemisphere. Other markers of astrocytes, including $S100{\beta}$, glutamate transporter EAAT2, the potassium channel Kir4.1 and glutamine synthase, showed patterns similar to that of GFAP in both NMDA- and KA-injected cortexes. More importantly, astrocyte disappearance and/or functional loss preceded neuronal death in the KA-injected brain. Taken together, these results suggest that loss of astrocyte support to neurons may be a critical cause of delayed neuronal death in the injured brain.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• v.1
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• pp.59-66
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• 2006

This research is based on the information compiled on the occurrence of maritime casualties onboard ships registered under Central American Region (CAR) flag States. Due to nonexistence of writing reports in anyone of the countries that are integrating this Region, the information was compiled by the author through personal communication with the people involved in the casualties. The information was compiled by typing up the text and digitizing on the computer for the respective data base. For each casualty occurred, the following information was compiled, date and type of the casualty, position of the ship at the time of the casualty, dimension of the ship, number of people affected by the casualty, and cause and consequences of the casualty. Based on the number of people affected (death and disappear) by the casualties occurred was calculated the mortality rate by 100,000 persons and then compared with the Japanese mortality rate. Furthermore were analyzed the CAR maritime authorities competences and then were compared to that the Japanese counter part. In addition, the implementation rate of the International Maritime Organization (IMO) and International Labor Organization (ILO) conventions ratified by the CAR countries were analyzed. The objective of this research was to compiled and analyze the occurrences of maritime casualties happened on board the ships registered under the CAR Flag States, in order to determine the causes of these accidents. The results of the analysis enable us to better understand of the maritime safety situation of the ships that are registered under the CAR flag States. In order to reduce the occurrence of maritime casualties are proposed a series of measures based on the differences found then the comparison between CAR and Japan. Based on the results of this research, is possible to conclude that the inaccessibility of atmospheric information and the lack of safety measures onboard has been the main cause of the maritime casualties happened in the Pacific side of the CAR.

• Restorative Dentistry and Endodontics
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• v.23 no.1
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• pp.487-501
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• 1998

In the case of CAD/CAM ceramic inlay restorations, if isthmus width is widened too much, it may cause fracture of remaining tooth structure or loss of bonding at the luting interface because of excessive displacement of buccal or lingual cusps under occlusal loads. So to clarify the criterior of widening isthmus width, this study was designed to test the tensile bond strength and bond failure mode between dentin and ceramic cemented with luting composite resin cements. Cylindrical ceramic blocks(Vita Cerec Mark II, d=4mm) were bonded to buccal dentin of 40 freshly extracted third molars with 4 luting composite resin cements(group1 : Scotchbond Resin Cement/Scotchbond Multi-Purpose, group2 : Duolink Resin Cement/ All-Bond 2, group3: Bistite Resin Cement/Ceramics Primer, and group4:Superbond C&B). Tensile bond test was done under universal testing machine using bonding and measuring alignment blocks(${\phi}ilo$ & Urn, 1992). After immersion of fractured samples into 1 % methylene blue for 24 hours, failure mode was analysed under stereomicroscope and SEM. Results: The tensile bond strength of goup 1, 2 & 4 was $13.97{\pm}2.90$ MPa, $16.49{\pm}3.90$ MPa and $16.l7{\pm}4.32$ MPa, respectively. There was no statistical differences(p>0.05). But, group 3 showed significantly lower bond stregnth($5.98{\pm}1.l7$ MPa, p<0.05). In almost all samples, adhesive fractures between dentin and resin cements were observed. But, in group 1, 2 & 4, as bond strength increased, cohesive fracture within resin cement was observed simultaneously. And, in group 3, as bond strength decreased, cohesive fracture between hybrid layer and composite resin cement was also observed. Cohesive fracture within dentin and porcelain adhesive fracture were not observed. In conclusion, although adhesive cements were used in CAD/CAM -fabricated ceramic inlay restorations, the conservative priciples of cavity preparation must be obligated.

• The Korean Journal of Physiology and Pharmacology
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• v.25 no.6
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• pp.565-574
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• 2021

Astrocytes are activated in response to brain damage. Here, we found that expression of Kir4.1, a major potassium channel in astrocytes, is increased in activated astrocytes in the injured brain together with upregulation of the neural stem cell markers, Sox2 and Nestin. Expression of Kir4.1 was also increased together with that of Nestin and Sox2 in neurospheres formed from dissociated P7 mouse brains. Using the Kir4.1 blocker BaCl₂ to determine whether Kir4.1 is involved in acquisition of stemness, we found that inhibition of Kir4.1 activity caused a concentration-dependent increase in sphere size and Sox2 levels, but had little effect on Nestin levels. Moreover, induction of differentiation of cultured neural stem cells by withdrawing epidermal growth factor and fibroblast growth factor from the culture medium caused a sharp initial increase in Kir4.1 expression followed by a decrease, whereas Sox2 and Nestin levels continuously decreased. Inhibition of Kir4.1 had no effect on expression levels of Sox2 or Nestin, or the astrocyte and neuron markers glial fibrillary acidic protein and β-tubulin III, respectively. Taken together, these results indicate that Kir4.1 may control gain of stemness but not differentiation of stem cells.

• Safety and Health at Work
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• v.12 no.3
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• pp.304-310
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• 2021

Background: Healthcare settings have been recognized among the most hazardous places to work. Based on the five categories of occupational hazards that were identified by the ILO and WHO, this study aimed to analyze policy framework relevant to occupational health protection of health workers (HWs) in public health service in China, then discussed how to share the experience of the National Health Service (NHS) England for improvement. Methods: Based on policy learning theories, policy analysis and qualitative interview were used in this study. Results: In the Chinese public health service, at least five laws related to the regulation of occupational health protection for HWs; however, enforcement of relevant laws was separated and multi-centered; the national monitoring system, which targeted to occupational hazards and health outcome for HWs in China, had yet to be developed; the top three priorities were workplace violence, bloodborne pathogens, and musculoskeletal disorders; national strategies included Security Hospital, and Healthy China 2030. In NHS England, three laws were fundamental; several monitoring systems had been set up, including NHS Staff Survey, Commissioning for Quality and Innovation incentive scheme; mental health, musculoskeletal problem, and nutrition disorder and overweight were raised great concern; Health and Safety, and NHS Healthy Workforce Program were critical nationwide strategies. Conclusion: There were several similarities as well as differences between the Chinese public health system and NHS England, which laid foundation of learning by China. Recommendations of improving occupational health policies in China were provided, based on the lessons learned from the NHS England.

• Journal of the Korean Society of Safety
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• v.36 no.4
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• pp.47-53
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• 2021

The fatality rate is used to estimate each country's risk level. However, the fatality rate is calculated using the number of fatal accidents and workers, which is collected differently across countries. It is therefore problematic to use these numbers in an equivalent way. This study proposes a new approach for calculating the number of full-time equivalent workers when evaluating individual countries' fatality rate by suggesting an equivalent condition for the calculation of the number of full-time equivalent workers. This study proceeds in three steps: (i) analysis of the fatality rate among various countries; (ii) fatality rate calculation using the full-time equivalent workers; and (iii) comparison of the fatality rate among various countries. The study found that for the fatality rate based on national data, the fatality rate in South Korea (1.72‱) is 10 times higher than that in United Kingdom (0.17‱). However, according to the number of full-time equivalent workers, the fatality rate in South Korea (1.86‱) was three times higher than that in the United Kingdom (0.56‱). These findings reveal a difference in the fatality rate depending on the method used to calculate the number of full-time equivalent workers. Therefore, the number of full-time equivalent workers must be calculated for each country to accurately compare the fatality rate. Ultimately, the study's results highlight the need for clearer standards in the assessment of the fatality rate by country in international organizations such as the ILO.

• Safety and Health at Work
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• v.14 no.4
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• pp.368-374
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• 2023

Background: Recognizing that access to safe and healthy working conditions is a human right, the World Health Organization (WHO) calls for specific occupational safety and health (OSH) programs for health workers (HWs). The WHO health systems' building blocks, and the International Labour Organization (ILO), highlight the importance of information as part of effective systems. This study examined how OSH stakeholders access, use, and value an occupational health information system (OHIS). Methods: A cross-sectional survey of OSH stakeholders was conducted as part of a larger quasi experimental study in four teaching hospitals. The study hospitals and participants were purposefully selected and data collected using a modified questionnaire with both closed and open-ended questions. Quantitative analysis was conducted and themes identified for qualitative analysis. Ethics approval was provided by the University of Pretoria and University of British Columbia. Results: There were 71 participants comprised of hospital managers, health and safety representatives, trade unions representatives and OSH professionals. At least 42% reported poor accessibility and poor timeliness of OHIS for decision-making. Only 50% had access to computers and 27% reported poor computer skills. When existing, OHIS was poorly organized and needed upgrades, with 85% reporting the need for significant reforms. Only 45% reported use of OHIS for decision-making in their OSH role. Conclusion: Given the gap in access and utilization of information needed to protect worker's rights to a safe and healthy workplace, more attention is warranted to OHIS development and use as well as education and training in South Africa and beyond.

• Tuberculosis and Respiratory Diseases
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• v.43 no.6
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• pp.945-953
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• 1996

Background : Many acute and chronic lung diseases including pneumoconiosis are characterized by the presence of increased numbers of activated macrophages. These macrophages generate several inflammatory cell chemoattractants, by which neutrophil migrate from vascular compartment to the alveolar space. Recruited neutrophils secrete toxic oxygen radicals or proteolytic enzymes and induce inflammatory response. Continuing inflammatory response results in alteration of the pulmonary structure and irreversible fibrosis. Recently, a polypeptide with specific neutrophil chemotactic activity, interleukin-8(IL-8), has been cloned and isolated from a number of cells including : monocytes, macrophages and fibroblasts. IL-1 and/or TNF-${\alpha}$ preceded for the synthesis of IL-8, and we already observed high level of IL-1 and TNF-${\alpha}$ in the pneumoconioses. So we hypothesized that IL-8 may be a central role in the pathogenesis of pneumoconiosis. In order to evaluate the clinical utility of IL-8 as a biomarker in the early diagnosis of pneumoconiosis, we investigated the increase of IL-8 in the pneumoconiotic patient and the correlation between IL-8 level and progression of pneumoconiosis. Method : We measured IL-8 in the serum of 48 patients with pneumoconiosis and 16 persons without dust exposure history as a control group. Pneumoconiotic cases were divided into 3 groups according to ILO Classification : suspicious group(n=16), small opacity group(n=16) and large opacity group(n=16). IL-8 was measured by a sandwich enzytne immunoassay technique. All data were expressed as the $mean{\pm}standard$ deviation. Results: 1) The mean value of age was higher in the small opacity and large opacity group than comparison group, but smoking history was even. Duration of dust exposure was not different among 3 pneumoconiosis groups. 2) IL-8 level was $70.50{\pm}53.63pg/m{\ell}$ in the suspicious group, $107.50{\pm}45.88pg/m{\ell}$ in the small opacity group, $132.50{\pm}73.47pg/m{\ell}$ in the large opacity group and $17.85{\pm}33.85pg/m{\ell}$ in the comparison group. IL-8 concentration in all pneumoconiosis group was significant higher than that in the comparison group(p<0.001). 3) IL-8 level tended to increase with the progression of pneumoconiosis. Multiple comparison test using Anova/Scheffe analysis showed a significant difference between suspicious group and large opacity group(p<0.05). 4) The level of IL-8 was correlated with the progression of pneumoconiosis(r=0.4199, p<0.05). Conclusion : IL-8 is thought to be a good biomarker for the early diagnosis of pneumoconiosis.