• Toxicological Research
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• v.34 no.4
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• pp.333-341
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• 2018

Ferulate is a phenolic compound abundant in wheat germ and bran and has been investigated for its beneficial activities. The aim of the present study is to evaluate the efficacy of ferulate against the oxidative stress-induced imbalance of protein tyrosine kinases (PTKs), protein tyrosine phosphatases (PTPs), and serine/threonine protein phosphatase 2A (PP2A), in connection with our previous finding that oxidative stress-induced imbalance of PTKs and PTPs is linked with proinflammatory nuclear factor-kappa B $(NF-{\kappa}B)$ activation. To test the effects of ferulate on this process, we utilized two oxidative stress-induced inflammatory models. First, YPEN-1 cells were pretreated with ferulate for 1 hr prior to the administration of 2,2'-Azobis(2-methylpropionamidine) dihydrochloride (AAPH). Second, 20-month-old Sprague-Dawley rats were fed ferulate for 10 days. After ferulate treatment, the activities of PTKs, PTPs, and PP2A were measured because these proteins either directly or indirectly promote $NF-{\kappa}B$ activation. Our results revealed that in YPEN-1 cells, ferulate effectively suppressed AAPH-induced increases in reactive oxygen species (ROS) and $NF-{\kappa}B$ activity, as well as AAPH-induced PTK activation. Furthermore, ferulate also inhibited AAPH-induced PTP and PP2A inactivation. In the aged kidney model, ferulate suppressed aging-induced activation of PTKs and ameliorated aging-induced inactivation of PTPs and PP2A. Thus, herein we demonstrated that ferulate could modulate PTK/PTP balance against oxidative stress-induced inactivation of PTPs and PP2A, which is closely linked with $NF-{\kappa}B$ activation. Based on these results, the ability of ferulate to modulate oxidative stress-related inflammatory processes is established, which suggests that this compound could act as a novel therapeutic agent.

• Journal of Preventive Medicine and Public Health
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• v.21 no.1 s.23
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• pp.99-112
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• 1988

Questionnaires and blood pressure measurements were administered to 279 medical school undergraduates in 1987 to investigate the relationship between psychosocial factors and blood pressure as well as reliability and validity of the Framingham Type A Behavior Scale(FTA). The reliability coefficients of SCL-90-R and nh measured by Spearman-Brown haves split test were $0.57{\sim}0.91$. The factors of FTA extracted by principal component analysis were hard-driving competitiveness factor and impatience factor(2-factor solution) . The total score of nh was positively correlated with relative weight and place raised but the correlations were insignificant, and had significantly positive but weak correlations with depression, anxiety, hostility, paranoid, and psychoticism subscales of SCL-90-R. In the univariate analysis of blood pressures, relative weight and family history were significant in systolic pressure in males and economic status was significant in blood pressures in both sexes. For diastolic pressure, relative weight and frequency of alcohol intake were significant in males and relative weight was in females. After controlling relative weight, the frequency of alcohol intake for diastolic pressure and economic status for systolic pressure were significant in males. The important variables selected by stepwise regression analysis were relative weight and economic status for systolic pressure of males and relative weight and the frequency of alcohol intake for diastolic pressure. At the level of alpha 0.1, depression subscale was added to the model, changing coefficient of determination 0.206 to 0.217. In females, economic status and relative weight were selected for systolic pressure and for diastolic pressure body mass index alone, but the model of blood pressure for females was considered to be unstable due to small sample size(56). FTA was unrelated to the blood pressures in both sexes.

• Proceedings of the Korean Society of Near Infrared Spectroscopy Conference
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• 2001.06a
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• pp.1281-1281
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• 2001

Near-infrared (NIR) spectra have bean measured for high-density (HDPE), linear low-density (LLDPE), and low-density (LDPE) polyethylene in pellet or thin films. The obtained spectra have been analyzed by conventional spectroscopic analysis methods and chemometrics. By using the second derivative, principal component analysis (PCA), and two-dimensional (2D) correlation analysis, we could separate many overlapped bands in the NIR. It was found that the intensities of some bands are sensitive to density and crystallinity of PE. This may be the first time that such bands in the NIR region have ever been discussed. Correlations of such marker bands among the NIR spectra have also been investigated. This sort of investigation is very important not only for further understanding of vibration spectra of various of PE but also for quality control of PE by vibrational spectroscopy. Figure 1 (a) and (b) shows a NIR reflectance spectrum of one of the LLDPE samples and that of PE, respectively. Figure 2 shows a PC weight loadings plot of factor 1 for a score plot of PCA for the 16 kinds of LLDPE and PE based upon their 51 NIR spectra in the 1100-1900 nm region. The PC loadings plot separates the bands due to the $CH_3$ groups and those arising form the $CH_2$ groups, allowing one to make band assignments. The 2D correlation analysis is also powerful in band enhancement, and the band assignments based upon PCA are in good agreement with those by the 2D correlation analysis.(Figure omitted). We have made a calibration model, which predicts the density of LLDPE by use of partial least square (PLS) regression. From the loadings plot of regression coefficients for the model , we suggest that the band at 1542, 1728, and 1764 nm very sensitive to the changes in density and crystalinity.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.5
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• pp.77-83
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• 2020

4WD technology is being actively applied to passenger cars. Therefore, dry multi-plate clutches are used for transfer cases. On the other hand, dry clutches have problems related to large vibrations and poor ride quality. To solve this problem, this paper proposes a multi-plate clutch with an MR fluid. When fastening the multi-plate clutch in the transfer case, the proposed MR clutch was applied to reduce the shock and friction, which is a key component in a four-wheel-drive system. MR multi-plate clutch has a fluid coupling mode and a compression mode. A torque model equation was derived for the optimal design. The analysis was performed using Ansys Maxwell to optimize the design parameters of the multi-plate clutch. Electromagnetic field analysis confirmed the strength of the magnetic field when the number of disks and plates were changed, and the maximum strength of the magnetic field was 0.45 Tesla. By applying this to the torque equation, the spacing between the plates was 2 mm, and the inner and outer diameters of the plates were selected to be 45 mm and 55 mm, respectively. Overall, this paper proposes an optimal design technique to maximize the performance of an MR multi-plate clutch.

• The Journal of the Acoustical Society of Korea
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• v.18 no.5
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• pp.68-77
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• 1999

The paper looked into the effects of the spectral properties (waveform) of the high intensity focused ultrasound on suppression of the ultrasonic cavitation. Three different types of ultrasound were considered in the study, which were sinusoidal (1 MHz, 5 MPa), frequency modulated (from 1 MHz to 6 MHz for 10 ㎲, 5 MPa), asymmetrically shocked (fundamental frequency 1 MHz, peak positive pressure 12 MPa, peak negative pressure -4 MPa). The temporal response of an air bubble in water initially 1 ㎛ in radius to each type of the ultrasound was predicted using Gilmore bubble dynamic model and Church's rectified gas diffusion equation. It was shown that the radially pulsating amplitude of the bubble was greatly reduced for the frequency modulated wave and was little decreased for the shock wave, compared to the case that the bubble was exposed to the sinusoidal wave. It is interesting that the bubble response to the frequency modulated wave remains similar when the frequency component of the modulated ultrasound is beyond the bubble resonant frequency 3 MHz. This implies that, although the ultrasound is modulated up to 3MHz rather than up to the present 6 MHz, it is likely to produce similar cavitation suppression effects. In practice, it means that a typical narrow band ultrasonic transducer can be taken to generate an appropriate frequency modulated ultrasound to reduce cavitation activity. The present study indicates that ultrasonic cavitation may be suppressed to some extent by a proper spectral modification of high intensity ultrasound.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.6
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• pp.3950-3960
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• 2014

In this study, the drag forces on a submerged square cylinder were analyzed using a three dimensional hydrodynamic model. The numerical results were compared with the experimental results to check the reliability of the numerical simulations, and the characteristics of the drag forces with the relative depths were analyzed by analyzing the pressure acting on the cylinder surface, which are normally difficult to measure experimentally. The numerical results showed that the drag forces acting on a submerged square cylinder originate mainly from the pressure forces, and component of the shear forces decreased with increasing relative depth. The pressure coefficient distributions showed that in the case of a low relative depth, a relatively high pressure was formed in the front of a cylinder, and a relatively low pressure was formed in the rear, which gives a high drag coefficient. In a high relative depth, the pressure in the front decreased and pressure in the rear increased, which is a similar phenomenon to that normally observed in two dimensional square cylinder flow. The effect of the static pressure was analyzed and the surface elevation difference between the front and rear zone of a cylinder has a limited effect on the drag forces. Finally, the numerical results showed that the drag forces acting on a submerged square are dominated by the dynamic pressure formed by three dimensional flow and the distribution of local surface elevation.

• Journal of KIISE:Computing Practices and Letters
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• v.14 no.6
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• pp.567-581
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• 2008

As the size of the web is growing explosively, search engines are becoming increasingly important as the primary means to retrieve information from the Internet. A search engine periodically downloads web pages and stores them in the database to provide readers with up-to-date search results. The web crawler is a program that downloads and stores web pages for this purpose. A large-scale search engines uses a parallel web crawler to retrieve the collection of web pages maximizing the download rate. However, the service architecture or experimental analysis of parallel web crawlers has not been fully discussed in the literature. In this paper, we propose an architecture of the parallel web crawler and discuss implementation issues in detail. The proposed parallel web crawler is based on the coordinator/agent model using multiple machines to download web pages in parallel. The coordinator/agent model consists of multiple agent machines to collect web pages and a single coordinator machine to manage them. The parallel web crawler consists of three components: a crawling module for collecting web pages, a converting module for transforming the web pages into a database-friendly format, a ranking module for rating web pages based on their relative importance. We explain each component of the parallel web crawler and implementation methods in detail. Finally, we conduct extensive experiments to analyze the effectiveness of the parallel web crawler. The experimental results clarify the merit of our architecture in that the proposed parallel web crawler is scalable to the number of web pages to crawl and the number of machines used.

• Journal of the Korean Society for Advanced Composite Structures
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• v.2 no.4
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• pp.1-10
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• 2011

This study investigates the performance of composite (steel-concrete) frame structures through numerical experiments on individual connections. The innovative aspects of this research are in the use of connections between steel beams and concrete-filled tube (CFT)columns that utilize a combination of low-carbon steel and shape memory alloy (SMA) components. In these new connections, the intent is to utilize the recentering provided by super-elastic shape memory alloy tension bars to reduce building damage and residual drift after a major earthquake. The low-carbon steel components provide excellent energy dissipation. The analysis and design of these structures is complicated because the connections cannot be modeled as being simply pins or full fixity ones they are partial restraint (PR). A refined finite element (FE) model with sophisticated three dimensional (3D) solid elements was developed to conduct numerical experiments on PR-CFT joints to obtain the global behavior of the connection. Based on behavioral information obtained from these FE tests, simplified connection models were formulated by using joint elements with spring components. The behavior of entire frames under cyclic loads was conducted and compared with the monotonic behavior obtained from the 3D FE simulations. Good agreement was found between the simple and sophisticated models, verifying the robustness of the approach.

• Journal of dental hygiene science
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• v.9 no.1
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• pp.53-59
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• 2009

Infection control is now recognized as an important quality indicator in dental health service setting. The purpose of this study was to develop and validate Dental Hygienist's Infection Control Practice Scale for quality management of dental health service in Korea. The data of 254 dental hygienists was subjected to exploratory factor analysis using SPSS 16.0 and confirmatory factor analysis using AMOS 16.0. The total items of preliminary scale were 21 items and 5 subscale. Principal component analysis was completed with Varimax rotation. The results show a change in factor structure from 5 factor solution to 4 factor solution. The confirmatory factor analysis confirmed the four subscales(Immunization and periodic tests, Clinical procedure, Handwashing, Personal protection) which have a total of 12 items. After the item deleted because factor loading was low, measured model was tested. The results of the measurement model indicated fit indices: $x^2$= 79.593(df = 38, 0 = 0.000), RMR = 0.045, GFI = 0.940, CFI = 0.904, AGFI = 0.896, NFI = 0.837, TLI = 0.861, RMSEA = 0.67. The squared correlation between four constructs were less than the average variance extracted(AVE) of four constructs. Multiple regression analysis was completed. Dependent variable was the perceived infection control practice by dental hygienist. Independent variables were four summated subscales(R = 0.552, $R^2$= 0.304, Adjusted $R^2$= 0.431, F = 25.813, p = 0.000). Unstandardized coefficients of three independent variables were statistically significant.

• Journal of the Korean Data and Information Science Society
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• v.27 no.3
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• pp.677-687
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• 2016

Among lots of sabermetric statistics for baseball batters' ability, the wins above replacement (WAR) is the most popular statistic in MLB. However, there exists a difficulty applying WAR to KBO, since KBO data do not have position adjustment, league adjustment and park factor which are essential in calculating WAR. In this paper, using five statistics for both KBO and MLB qualified batters, we propose hitting ability index (HAI), an alternative sabermetric indices to represent batters' ability. Comparing HAI with WAR of MLB batters, we evaluate the validity of HAI and then applied HAI to 2015 KBO data in which HAI is analyzed statistically with respect to different teams, ages, and positions. Moreover, the linear relationship between KBO batter's HAI and their annual salary is discussed. Grouping 46 KBO batters based on confidence region of the regression model for annual salary, we also statistically investigate batter's annual salary in these groups with respect to several factors.