• Management & Information Systems Review
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• v.39 no.2
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• pp.17-37
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• 2020

The purpose of this study is to investigate the global spillover effects through the existence of linear and nonlinear causal relationships between the US, European and BRIC financial markets after the period from the introduction of the Euro, the financial crisis and the subsequent EU debt crisis in 2007~2010. Although the global spillover effects of the financial crisis are well described, the nature of the volatility effects and the spread mechanisms between the US, Europe and BRIC stock markets have not been systematically examined. A stepwise filtering methodology was introduced to investigate the dynamic linear and nonlinear causality, which included a vector autoregressive regression model and a multivariate GARCH model. The sample in this paper includes the post-Euro period, and also includes the financial crisis and the Eurozone financial and sovereign crisis. The empirical results can have many implications for the efficiency of the BRIC stock market. These results not only affect the predictability of this market, but can also be useful in future research to quantify the process of financial integration in the market. The interdependence between the United States, Europe and the BRIC can reveal significant implications for financial market regulation, hedging and trading strategies. And the findings show that the BRIC has been integrated internationally since the sub-prime and financial crisis erupted in the United States, and the spillover effects have become more specific and remarkable. Furthermore, there is no consistent evidence supporting the decoupling phenomenon. Some nonlinear causality persists even after filtering during the investigation period. Although the tail distribution dependence and higher moments may be significant factors for the remaining interdependencies, this can be largely explained by the simple volatility spillover effects in nonlinear causality.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.12
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• pp.4752-4759
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• 2010

Using Technology Acceptance Model and flow theory as our foundation, this paper investigates the interrelationships among social influence, individual cognition, flow, and actual usage in the Web 2.0 environment. According to TAM, users evaluate perceived usefulness(PU) and ease of use(PEU) of information technology(IT) in accepting the innovative IT. Along with users' cognitive evaluation(i.e. PU and PEU), in case of UCC(user-created-contents), which is one of the representative Web 2.0 features, flow also has a significant effect on users' usage. Accordingly, the current study involve cognitive elements such as PU and PEU as well as flow of enjoyable state during using IT in exploring antecedents leading to UCC usage. On one hand, we consider the effect of social influence on users' cognition and flow toward actual usage because the more users creates Web contents, the more long-tail situation prevails on the Internet. Web 2.0 becomes a kind of social phenomena. The empirical results show that social influence affects positively both PU/PEU and flow. Users' cognitive evaluation and flow have positive impacts on users' UCC usage.

• The Korean Journal of Physiology and Pharmacology
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• v.1 no.3
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• pp.251-262
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• 1997

Peripheral nerve injury sometimes leads to neuropathic pain and depletion of calcitonin gene related-peptide (CGRP) and substance P (SP) in the spinal cord. However, the pathophysiological mechanisms for depletion of CGRP and SP following the neurorathic injury are still unknown. This study was performed to see whether the distribution of immunoreactivity for CGRP and SP in the superficial dorsal horn and dorsal root ganglia(DRG) was related to the distance between the DRG and injury site. To this aim, we compared two groups of rats; one group was subjected to unilateral inferior and superior caudal trunk transections at the level between the S3 and S4 spinal nerves (S34 group) and the other group at the levels between the S1 and S2, between S2 and S3 and between S3 and S4 spinal nerve (S123 group). The transections in both groups equally eliminated the inputs from the tail to the S1-3 DRG, but the distance from the S1/S2 DRG to the injury site was different between the two groups. Immunostaining with SP and CGRP antibody was done in the S1-S3 spinal cord and DRG of the two groups 1 and 12 weeks after the injury. The results obtained are as follows: 1. The immunoreactivity for CGRP and SP in the ipsilateral superficial dorsal horn and DRG decreased 1 and 12 weeks after neuropathic nerve injury. 2. The immunoreactive area of SP and CGRP in the S1 dorsal horn was smaller in the S123 group than in the S34 group, whereas that in the S3 dorsal horn was not significantly different between the two groups. The number of SP-immunoreactive DRG cells decreased on the neuropathic side as compared to the sham group's in all DRGs of experimental groups except the S1 DRG of the S34 group. These results suggest that the amounts of SP and CGRP in the dorsal horn and DRG following neuropathic injury inversely decrease according to the distance between the DRG and injury site.

• The Korean Journal of Nuclear Medicine
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• v.24 no.2
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• pp.317-324
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• 1990

Liposome was labelled with $^{99m}Tc$ after negative charged liposome was formed with combination of a few lipid components. $^{99m}Tc$ liposome was injected through the tail vein of C3H mice bearing fibrosarcoma and biodistribution of $^{99m}Tc$ liposome was evaluated. The results were as follows: 1) We confirmed formation of liposome which was small unillamellar and multilamellar vesicles. 2) In this experiment the optimal concentration of $SnCl_2$ was $156{\mu}g/ml$ to label liposome with $^{99m}Tc$ and labelling efficiency was 95%. 3) The labelled liposome was stable when it was incubated with human serum for 24 hours. Mean labelling efficiency was 94% at 24 hour. 4) The main uptake sites of Tc-99m liposome were liver and spleen. It showed significantly higher uptake than $^{99m}Tc$ HSA (p < 0.001). 5) $^{99m}Tc$ liposome uptake in tumor tissue was not significantly higher than $^{99m}Tc$ HSA uptake. In conclusion, $^{99m}Tc$ liposome disclosed high labelling efficiency and was highly stable. Liver and spleen were main uptake sites of $^{99m}Tc$ liposome. The uptake mechanism of $^{99m}Tc$ liposome also seemed to be different from that of $^{99m}Tc$ HSA. We conclude that $^{99m}Tc$ liposome would be a promising agents for the imaging of some tumor.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.34 no.1
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• pp.36-48
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• 2008

To repair bone defects in the oral and maxillofacial field, bone grafts including autografts, allografts, and artificial bone are used in clinical dentistry despite several disadvantages. The purpose of this study was to evaluate new bone formation and healing in rat calvarial bone defects using hydroxyapatite (HA, $Ca_{10}[PO_4]_6[OH]_2,\;Bongros^{(R)}$, Bio@ Co., KOREA) and tricalcium phosphate (${\beta}-TCP,\;Ca_3[PO_4]_2$, Sigma-Aldrich Co., USA) mixed at various ratios. Additionally, this study evaluated the effects of type I collagen (Rat tail, BD Biosciences Co., Sweden) as a basement membrane organic matrix. A total of twenty, 8-week-old, male Sprague-Dawley rats, weighing 250-300g, were divided equally into a control group (n=2) and nine experimental groups (n=2, each). Bilateral, standardized transosseous circular calvarial defects, 5.0 mm in diameter, were created. In each experimental group, the defect was filled with HA and TCP at a ratio of 100:0, 80:20, 70:30, 60:40, 50:50, 40:60, 30:70, 20:80, and 0:100 with or without type I collagen. Rats were sacrificed 4 and 8 weeks post-operation for radiographic (standardized plain film, Kodak Co., USA), histomorphologic (H&E [Hematoxylin and Eosin], MT [Masson Trichrome]), immunohistochemical staining (for BMP-2, -4, VEGF, and vWF), and elementary analysis (Atomic absorption spectrophotometer, Perkin Elmer AAnalyst $100^{(R)}$). As the HA proportion increased, denser radiopacity was seen in most groups at 4 and 8 weeks. In general radiopacity in type I collagen groups was greater than the non-collagen groups, especially in the 100% HA group at 8 weeks. No new bone formation was seen in calvarial defects in any group at 4 weeks. Bridging bone formation from the defect margin was marked at 8 weeks in most type I collagen groups. Although immunohistochemical findings with BMP-2, -4, and VEGF were not significantly different, marked vWF immunoreactivity was present. vWF staining was especially strong in endothelial cells in newly formed bone margins in the 100:0, 80:20, and 70:30 ratio type I collagen groups at 8 weeks. The calcium compositions from the elementary analysis were not statistically significant. Many types of artificial bone have been used as bone graft materials, but most of them can only be applied as an inorganic material. This study confirmed improved bony regeneration by adding organic type I collagen to inorganic HA and TCP mixtures. Therefore, these new artificial bone graft materials, which are under strict storage and distribution systems, will be suggested to be available to clinical dentistry demands.

• Journal of the East Asian Society of Dietary Life
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• v.15 no.4
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• pp.386-396
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• 2005

The effects of spirulina-added salad dressing on lipid profiles and antioxidant biomarkers such as total glutathionine, TBARS value, carbonyl value, GPx, GR, SOD and paraoxonase activity in plasma or liver of mice were evaluated Sixteen male ICR mice weighing 20$\pm$2 g were divided into two groups and fed low fat ($5\%$ fat) diet (low fat control: LFC) and low fat control plus dressing diet (LFD) for eight weeks. Body weight, tissue weights of liver, heart and kidney, and the distribution of body fat deposition were not significantly different between two groups. Also, the profile of TG, TC, LDL and HDL cholesterol were similar between two groups. The DNA damage was determined using the comet assay (single cell gel assay) with alkaline electrophoresis and quantified by measuring tail length (TL). Spirulina salad dressing consumption resulted in significant decrease in lymphocyte DNA damage expressed by TL (LFC: $28.8{\mu}m$, LFD: $20.3{\mu}m$). Additionally, salad dressing consumption for 8 wks decreased the lipid peroxidation assayed by TBARS to $12.6\%$ compared with the control. The levels of antioxidant vitamins such as $\beta$-carotene were significantly higher in plasma of LFD group than those in LFC group based on HPLC method This study shows that spirulina-added salad dressing exerts degenerative disease-protective effects on oxidative DNA damage and lipid peroxidation possibly via a free radical levels.

• Korean Journal of Microbiology
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• v.27 no.1
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• pp.1-9
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• 1989

The locations of 5' ends as well as the splicing pattern of viral poly A(-) 19S RNA from monkey cells infected with SV40 were determined by a modification of primer extension method. The 5' end of this RNA mapped at the major cap site at nucleotide residue 325, used most frequently by SV40 late RNAs. The intron from nt.373 to nt.558 was removed as the ordinary cytoplasmic poly A(+) 19S RNA. The 3'end of this RNA was very heterogeneous and distributed over 1 kb upstream of polyadenylation site, as determined by S1 nuclease mapping. The reason for this normally initiated and spliced RNA to accumulate in the nucleus was investigated. In order to test whether the presence of unused 3' splice region on this RNA caused such subcellular distribution, cells were transfected with SV40 mutant KNA containing deletion around 3' splice site. The RNA deleted of 3' splice region accumulated mainly in the cytoplasm. This accumulation did not result from the increased stability of the RNA due to the deletion, since the wild type and mutant RNAs exhibited similar half lives after chase with actinomycin D. Therefore it is likely that the 19S spliced RNA is hindered from being transported into the cytoplasm due to some pre-splicing complexes formed at the unused 3' splice site.

• Journal of the Korean Geotechnical Society
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• v.30 no.11
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• pp.51-60
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• 2014

Load and Resistance Factor Design (LRFD) is one of the limit state design methods, and has been used worldwide, especially in North America. Also, the study for LRFD has been actively conducted in Korea. However, the data for LRFD in Korea were not sufficient, so resistance factors suggested by AASTTO have been used for the design in Korea. But the resistance factors suggested by AASHTO represent the characteristics of bedrocks defined in the US, therefore, it is necessary to determine the resistance factors for designs in Korea, which can reflect the characteristics of bedrocks in Korea. Also, the calculated probabilities of failure from conventional reliability analyses which commonly use log-normal distribution are not realistic because of the lower tail that can be extended to zero. Therefore, it is necessary to calibrate the resistance factors considering the lower-bound resistance. Thus, this study calculates the resistance factors using thirteen sets of drilled shaft load test results, and then calibrates the resistance factors considering the lower-bound resistance corresponding to a target reliability index of 3.0. As a result, resistance factors from conventional reliability analyses were determined in the range of 0.13-0.32 for the shaft resistance, and 0.19-0.29 for the base resistance, respectively. Also, the lower bounds of resistance were determined based on the Hoek-Brown failure criteria (2002) and GSI downgrading. Considering the lower-bound resistances, resistance factors increased by 0~8% for the shaft, and 0~13% for the base, respectively.

• Nuclear Engineering and Technology
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• v.22 no.1
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• pp.20-28
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• 1990

In this study the migration experiment using packed column with crushed tuff was conducted as a basic research to develop migration model of radionuclides through geologic media. The main emphasis was put on evaluating the validity of migration models. For this, two models were introduced: one is the model which is based on the assumption of instantaneous equilibrium reaction and the other the model based on kinetic process such as intraparticle diffusion. The coefficient of hydrodynamic dispersion in packed column was determined using iodine as nonsorbing tracer. The hydrodynamic dispersion coefficient, D$_{L}$ was shown to be 0.11$\times$10$^{-2}$ $\textrm{cm}^2$/min under the condition of the column porosity of 0.483 and the average water velocity of 0.915$\times$10$^{-2}$ cm/min. The distribution coefficient, Kd of Cs-137 on crushed tuff was 11.3 cc/g at the concentration of 2$\times$10$^{-6}$ M and the temperature of 2$0^{\circ}C$. The breakthrough curve of Cs-137 through packed column was shown to have an asymmetric curve in which long trailing tail appears at the end part of the curve. The results obtained from the comparison of introduced models with experimental data indicated that the mass transfer model with intraparticle diffusion as rate-controlling step simulated the behaviors of Cs-137 migration more adequately, when compared with the bulk reaction model in which the assumption of instantaneous equilibrium reaction was maded. Consequently, the intraparticle diffusion was found to be an important factor in the migration of Cs-137 through packed column.n.

• Journal of the Korean BIBLIA Society for library and Information Science
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• v.33 no.1
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• pp.5-24
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• 2022

As a new academic publication model is attempted to improve the transparency, efficiency, and speed of scientific knowledge production and distribution, the open peer review platform for verification and openness of peer review history is also activated. Publons is a global platform for tracking, validating, disclosing, and recognizing the peer-reviewed histories of more than 3 million researchers worldwide. This study analyzed the review activities of 579 researchers from domestic universities who are actively reviewing international journals through Publons. As a result of the analysis, first, researchers from domestic universities who actively review international academic journals were found to be in the fields of medicine and electrical and electronics, and in most fields, assistant professors or higher with high WOS indexed research papers are participating. Second, there was a long-tail phenomenon in which a small number of reviewers with extremely high number of review papers existed in all academic fields, and there was no significant difference in the number of review papers and review report length depending on the nationality, academic status, and age of the reviewers. Lastly, although there was a weak correlation between the amount of papers reviewed by reviewers and the number of published papers, it was found that researchers with an extremely large number of reviews do not necessarily produce as many research papers.