• Economic and Environmental Geology
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• v.34 no.1
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• pp.147-156
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• 2001

Titanomagnetites, the primary magnetic mineral in submarine basalts, generally has undergone some degree of low temperature oxidation to cation-deficient titanomaghemites. Synthetic analogues of natural titanomaghemite have been prepared by the removal of iron mechanism employing a low-temperature aqueous oxidation method. Along with the low-temperature oxidation of titanomagnetite, magnetic properties of titanomagnetite change sensitively. The results show that as the degree of oxidation increases, the Curie temperature (Tc) increases from $166^{\circ}C$ to $400^{\circ}C$, saturation magnetization (Ms) at room temperature decreases from 126.30 kAlm (25.26 emu/g) to 16.55 kAlrn (3.31 emu/g) monotonously, and coercive force (Hc) and coercivity of remanence (Hcr) increase from 6.13 kAlm (77 Oe) and 23.24 kAlm (292 Oe) to 38.83 kNm (488 Oe) and 47.03 kAlm (591 Oe), respectively. Low field susceptibility (X) decreases from $2023{\times}10^{-6}SI$ to $84{\times}10^{-6}S1$. Based on the results of this study, it is interpreted that the NRM intensity variations of the oceanic crust of presetnt day to 30 Ma is due to the formation of titanomahemites of various degree of oxidation by the low-temperature aqueous oxidation of titanomagnetite, while the magnetic intensity changes of the oceanic crust older than 30 Ma is presumably caused by the combined effect of the formation of titanomaghemites and subsequent inversion of titanomagnemites. DetaileJ causes of the variations of NRM intensity of the oceanic crust may be revealed by systematic studies of the oceanic-floor basalts in the future.

• Tuberculosis and Respiratory Diseases
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• v.75 no.4
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• pp.140-149
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• 2013

Background: Plasminogen activator inhibitor type 1 (PAI-1), an important regulator of plasminogen activator system which controls degradation of extracellular membrane and progression of tumor cells, and PAI-1 gene polymorphic variants have been known as the prognostic biomarkers of non-small cell lung cancer patients. Recently, experimental in vitro study revealed that transforming growth factor-${\beta}1$ initiated PAI-1 transcription through epithelial growth factor receptor (EGFR) signaling pathway. However, there is little clinical evidence on the association between PAI-1 A15T gene polymorphism and prognosis of Korean population with pulmonary adenocarcinoma and the influence of activating mutation of EGFR kinase domain. Methods: We retrospectively reviewed the medical records of 171 patients who were diagnosed with pulmonary adenocarcinoma and undergone EGFR mutation analysis from 1995 through 2009. Results: In all patients with pulmonary adenocarcinoma, there was no significant association between PAI-1 A15T polymorphic variants and prognosis for overall survival. However, further subgroup analysis showed that the group with AG/AA genotype had a shorter 3-year survival time than the group with GG genotype in patients with EGFR mutant-type pulmonary adenocarcinoma (mean survival time, 24.9 months vs. 32.5 months, respectively; p=0.015). In multivariate analysis of 3-year survival for patients with pulmonary adenocarcinoma harboring mutant-type EGFR, the AG/AA genotype carriers had poorer prognosis than the GG genotype carriers (hazard ratio, 7.729; 95% confidence interval, 1.414-42.250; p=0.018). Conclusion: According to our study of Korean population with pulmonary adenocarcinoma, AG/AA genotype of PAI-1 A15T would be a significant predictor of poor short-term survival in patients with pulmonary adenocarcinoma harboring mutant-type EGFR.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.10 no.5
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• pp.45-62
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• 2015

Entrepreneurial Orientation (EO hereafter) can be described as firm level entrepreneurial tendencies. Initially Miller(1983) clarifies the construct of EO, and defines an "entrepreneurial firm as one that engages in product marketing innovation, undertakes somewhat risky ventures, and is first to come up with proactive innovations, beating competitors to the punch". After Miller (1983), Covin & Slevin(1989) adopted EO as a uni-dimensional construct, and insisted that these three dimensions can be combined into a single scale. Since Covin & Slevin(1991), researchers including Lumpkin & Dess(1996) have explored the usefulness of EO. However not many attempts have been tried to summarize the results of previous empirical researches, and to suggest future research directions. To examine and find implications, current study classified the effects of EO as 1) main and mediating effects, 2) moderating effect, 3) other effects, and provide theoretical and empirical validation of EO, which suggested by Miller(2011). After analyzing research results published in major international and Korean journals in each research domain, current paper summarizes and evaluates previous research results, and then suggests research directions for the future. In doing so, we hope to provide some theoretical and practical insight for management of small and medium sized firms.

• Journal of the Institute of Convergence Signal Processing
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• v.19 no.3
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• pp.139-146
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• 2018

Underwater acoustic communication can be applied to various area such as scientific, commercial and military survey using Autonomous Underwater Vehicles and Unmanned Underwater Vehicles. Underwater communication is studying very actively by advanced country like United States. But differ from wireless communication in the air, underwater acoustic communication has some difficult problems, ISI(Inter Symbol Interference) due to multipath and limit of transmission bandwidth due to slow propagation of sound wave. In this paper, SC-FDE and OFDM transmission system for the cancellation of ISI in conjunction with underwater acoustic channel modeling are applied to the underwater simulation of communication. The performance of these methods in the simulation guide to possibility of adopting in underwater acoustic communication algorithm. For this purpose, we compare SER performance of SC-FDE with that of OFDM for modelled underwater channel. Underwater channel is generated by Bellhop model. Simulation results show above 5dB SNR gain at 10-3 SER. And it demonstrate SC-FDE is efficient method for underwater acoustic communication.

• The Journal of the Korea Contents Association
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• v.8 no.11
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• pp.412-425
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• 2008

One of the important elements for improving academic achievement of learners in education through e-learning is to support learners to study by finding questions they want with providing various evaluation questions. However, most of question retrieval systems usually depend on keyword search based on only a syntactical analysis and/or a hierarchical browsing system classified by the topics of subjects. In such a system it is not easy to find integrative questions associated with each other. In order to improve this problem, in this paper we proposed a question management and retrieval system which allows users to easily manage questions and also to effectively find questions for study on the Web. Then, we implemented a system that gives to access questions for the domain of C language programming. The system makes it possible to easily search questions related to not only a single theme but also questions integrated by interrelationship between topics and questions. This is done by supporting to be able to retrieve questions according to conceptual interrelationships between questions from user query. Consequently, it is expected that the proposed system will provide learners to understand the basic theories and the concepts of the subjects as well as to improve the ability of comprehensive knowledge utilization and problem-solving.

• International Journal of Highway Engineering
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• v.8 no.3 s.29
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• pp.143-153
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• 2006

The differences in the stress distribution and the critical stresses in concrete pavement systems were analyzed when the dual-wheel single-, tandem-, and tridem-axle loads were applied at the interior and the edge of the pavement. The effects of the concrete elastic modulus, slab thickness, foundation stiffness, and tire contact pressure were investigated. The stresses under the interior loads were calculated using the transformed field domain analysis and stresses under the edge loads were obtained using the finite element method. The critical stresses under the interior and the edge loads were compared with respect to various parameters and the equations to predict the ratio between the stresses under the edge and the interior loads were developed and verified. From this study, it was found that the trends of the changes in the critical concrete stresses under the interior and the edge loads were very similar and the critical stress locations under those loads were identical. The critical stress ratio, which was obtained by dividing the critical stress under the edge loads into that under the interior loads, decreased with increasing the number of axles. That ratio became larger as the concrete elastic modulus increased, the slab thickness increased, the foundation stiffness decreased, and the tire contact pressure increased.

• Korean Journal of Environmental Biology
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• v.24 no.1 s.61
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• pp.46-52
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• 2006

The mercury is among the most highly bioconcentrated toxic trace metals. Many national and international agencies and organisations have targeted mercury for the possible emission control. The mercury toxicity depends on its chemical form, among which alkylmercury compounds are the most toxic. A human cervix uterus cancer cell line HeLa cells was employed to investigate the effect of the toxic heavy metal mercury (Hg) and ionizing radiation. In the in vitro comet assays for the genotoxicity in the HeLa cells, the group of Hg treatment after irradiation showed higher DNA breakage than the other groups. The tail extent moment and olive tail moment of the control group were $4.88{\pm}1.00\;and\;3.50{\pm}0.52$ while the values of the only Hg treatment group were $26.90{\pm}2.67\;and\;13.16{\pm}1.82$, respectively. The tail extent moment and olive tail moment of the only 0.001, 0.005, 0.01 Hg group were $12.24{\pm}1.82,\;8.20{\pm}2.15,\;20.30{\pm}1.30,\;12.26{\pm}0.52,\;40.65{\pm}2.94\;and \;20.38{\pm}1.49$, respectively. In the case of Hg treatment after irradiation, the tail extent moment and olive tail moment of the 0.001, 0.005, 0.01 Hg group were $56.50{\pm}3.93,\;32.69{\pm}2.48,\;62.03{\pm}5.14,\;31.56{\pm}1.97,\;72.73{\pm}3.70\;and \;39.44{\pm}3.23$, respectively. The results showed that Hg induced DNA single-strand breaks or alkali labile sites as assessed by the Comet assay. It is in good agreement with the reported results. The mercury inhibits the repair of DNA. The bacterial formamidopyrimidine-DNA glycosylase (Epg protein) recognizes and removes some oxidative DNA base modifications. Enzyme inactivation by Hg (II) may therefore be due either to interactions with rysteine residues outside the metal binding domain or to very high-affinity binding of Hg (II) which readily removes Zn (II) from the zinc finger.

• Applied Chemistry for Engineering
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• v.17 no.3
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• pp.267-273
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• 2006

We have prepared PP/Ba-ferrite composite fabrics by a melt-blown spinning method and investigated the relationship between the properties of PP/Ba-ferrite composite fabrics and melt-blown processing factors. A PP composite containing Ba-ferrite as a magnetic particulate filler was prepared in the form of pellet from PP resin and Ba-ferrite powder by melt compounding using a single extruder. Screw turning force (rpm), DCD (die-to-collector distance), and Ba-ferrite content were changed. We measured diameters of fiber, mechanical, thermal, and magnetic properties for the composited PP fabrics. The elongation was increased and a fiber diameter and tensile strength were decreased as the spinning distance increased or screw turning force decreased. The crystallinity was increased with increasing spinning distance according to XRD. It was assumed that the orientation of crystalline domain in the neat PP without ferrite was increased by drawing in mechanical direction, however, the orientation in the PP composite was decreased according to XRD analysis. We measured a magnetic property of PP nonwoven fabric containing Ba-ferrite powder. A coercive force, maximum magnetization, and residual magnetization are reduced with the spinning distance. According to the result of TGA measurement, the heat resistance was increased with the Ba-ferrite powder content and with decreasing the spinning distance.

• Journal of Life Science
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• v.14 no.2
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• pp.325-330
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• 2004

The RAD3 gene of Saccharomyces cerevisiae is required for excision repair and is essential for cell viability. RAD3 encoded protein possesses a single stranded DNA-dependent ATPase and DNA and DNA-RNA helicase activities. To examine the extent of conservation of structure and function of RAD3 during eukaryotic evolution, the RAD3 homolog gene was isolated by screening of genomic DNA library. The isolated gene was designated as HRD3 (Homologue of RAD3 gene). The over-expressed HRD3 protein was estimated to be a 75 kDa in size which is in good agreement with the estimated by the nucleotide sequence of the cloned gene. Two-dimensional gel electrophoresis showed that a number of other protein spots dramatically disappeared when the HRD3 protein was overexpressed. The overexpressed RAD3 protein showed a toxicity in E. coli host, suggesting that this protein may be involved in the inhibition of protein synthesis and/or degradation of host protein. To determine which part of HRD3 gene contributes to the toxicity in E. coli, various fusion plasmids containing a partial sequence of HRD3 and lac'Z gene were constructed. These results suggest that the C-terminal domain of HRD3 protein may be important for both toxic effect in E. coli and for its role in DNA repair in S. pombe.

• Journal of rehabilitation welfare engineering & assistive technology
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• v.11 no.4
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• pp.339-348
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• 2017

The purpose of this study was to verify the validity and reliability of the computerized general neurocognitive test using intuitive evaluation techniques to reflect the needs of the elderly and to validate neurocognitive function appropriately. The subjects were 100 elderly people who were over 60 healthy people. To evaluate the comprehensive neurocognitive function of the elderly, Computerized Neuro-cognitive Function Test (CNT, cybermedic. Co., Korea) developed by CyberMedic was used. The test consist of attention test, memory test and the problem solving ability test. As a result of correlation analysis of CNT test items, it was possible to confirm the characteristics of measuring single domain of attention and memory test. The problem-solving ability test also showed a high level of significant correlation, although the purpose of measurement was different, but a comprehensive cognitive function test for problem solving was possible. In the reliability analysis, the half reliability and internal consistency of test - retest were significantly higher. As a result of the above study, we conclude that the comprehensive neurocognitive test items constituted in this study have achieved reproducibility and effectiveness.