• Asian Pacific Journal of Cancer Prevention
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• v.16 no.10
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• pp.4357-4361
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• 2015

Thunbergia Laurifolia Linn. (TL) is one of the most familiar plants in Thai traditional medicine that is used to treat various conditions, including cancer. However, the antitumor activity of TL or its constituents has never been reported at the molecular level to support the folklore claim. The present study was designed to investigate the antitumor effect of an aqueous extract of TL in human breast cancer cells and the possible mechanism(s) of action. An aqueous crude extract was prepared from dried leaves of TL. Folin-Ciocalteu colorimetric assays were used to determine the total phenolic content. Antiproliferative and cell cycle effects were evaluated in human breast adenocarcinoma MCF-7 cells by MTT reduction assay, cell growth inhibition, clonogenic cell survival, and flow cytometric analysis. Free radical generation by the extracts was detected using electron paramagnetic resonance spectroscopy. The exposure of human breast adenocarcinoma MCF-7 cells to a TL aqueous extract resulted in decreases in cell growth, clonogenic cell survival, and cell viability in a concentration-dependent manner with an $IC_{50}$ value of $843{\mu}g/ml$. Treatments with extract for 24h at $250{\mu}g/ml$ or higher induced cell cycle arrest as indicated by a significant increase of cell population in the G1 phase and a significant decrease in the S phase of the cell cycle. The capability of the aqueous extract to generate radical intermediates was observed at both high pH and near-neutral pH conditions. The findings suggest the antitumor bioactivities of TL against selected breast cancer cells may be due to induction of a G1 cell cycle arrest. Cytotoxicity and cell cycle perturbation that are associated with a high concentration of the extract could be in part explained by the total phenolic contents in the extract and the capacity to generate radical intermediates to modulate cellular proliferative signals.

• BMB Reports
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• v.45 no.7
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• pp.419-424
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• 2012

High-fat diets (HFD) and high-carbohydrate diets (HCD)-induced obesity through different pathways, but the metabolic differences between these diets are not fully understood. Therefore, we applied proton nuclear magnetic resonance ($^1H$ NMR)-based metabolomics to compare the metabolic patterns between C57BL/6 mice fed HCD and those fed HFD. Principal component analysis derived from $^1H$ NMR spectra of urine showed a clear separation between the HCD and HFD groups. Based on the changes in urinary metabolites, the slow rate of weight gain in mice fed the HCD related to activation of the tricarboxylic acid cycle (resulting in increased levels of citrate and succinate in HCD mice), while the HFD affected nicotinamide metabolism (increased levels of 1-methylnicotineamide, nicotinamide-N-oxide in HFD mice), which leads to systemic oxidative stress. In addition, perturbation of gut microflora metabolism was also related to different metabolic patterns of those two diets. These findings demonstrate that $^1H$ NMR-based metabolomics can identify diet-dependent perturbations in biological pathways.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.30 no.5
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• pp.79-87
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• 2002

Acoustic responses to pressure oscillations in axisymmetric combustion chamber are numerically investigated to examine the qualitative trend of acoustic instability in liquid rocket engine. Chamber operating condition and excitation frequency of oscillating pressure are selected as exciting parameters of acoustic instability. Artificial perturbation is simulated by total-pressure oscillation with sine wave at chamber inlet. Many approximations and simplifications are introduced without losing the essence of acoustic pressure response. First, steady-state solution for each operating condition is obtained and next, transient analysis is conducted. Depending on operating condition and excitation frequency, the distinct response characteristics are brought. Weak-strength flames and high-frequency excitation tend to cause sensitive acoustic pressure response leading to unstable pressure field. These results are analyzed based on the correlation with acoustic pressure responses from the previous works adopting laminar flamelet model.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.40 no.9
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• pp.752-759
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• 2012

This paper presents a mission orbit design method for spacecraft which use the sun-synchronous and ground repeat orbits. In this work, we have proposed a new design procedure, "Nonlinear simulation-based numerical optimization technique" using the commercial S/W's such as STK (Satellite Tool kit) and Matlab, which are widely adopted S/W's in the area of orbital mechanics and engineering analysis. Inclusion of all the perturbation effects on the spacecraft not only can more precisely satisfy the mission requirements for sun-synchronicity and repeated ground track, and also operational requirements such as minimum change in the S/C local time, maximization of the contact time with a specified ground station, etc. can be appropriately considered. Design examples for LEO sun-synchronous mission are presented to demonstrate the usefulness of the proposed method in this paper.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.5
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• pp.2778-2791
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• 2017

In the age of big data, distributed data providers need to ensure the privacy, while data analysts need to mine the value of data. Therefore, how to find the privacy-utility tradeoff has become a research hotspot. Besides, the adversary may have the background knowledge of the data source. Therefore, it is significant to solve the privacy-utility tradeoff problem in the distributed environment with side information. This paper proposes a distributed privacy-utility tradeoff method using distributed lossy source coding with side information, and quantitatively gives the privacy-utility tradeoff region and Rate-Distortion-Leakage region. Four results are shown in the simulation analysis. The first result is that both the source rate and the privacy leakage decrease with the increase of source distortion. The second result is that the finer relevance between the public data and private data of source, the finer perturbation of source needed to get the same privacy protection. The third result is that the greater the variance of the data source, the slighter distortion is chosen to ensure more data utility. The fourth result is that under the same privacy restriction, the slighter the variance of the side information, the less distortion of data source is chosen to ensure more data utility. Finally, the provided method is compared with current ones from five aspects to show the advantage of our method.

• KSBB Journal
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• v.28 no.4
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• pp.230-237
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• 2013

Amyloid ${\beta}$ peptide (A${\beta}$) still best known as a molecule to cause Alzheimer's disease (AD). AD is characterized by the accumulation and deposition of A${\beta}$ within the brain, leading to neuronal cell loss and perturbation of synaptic function by causing free radical formation, inflammation and apoptosis. We investigated the inflammatory action of A${\beta}$ on two types of brain cells, neuronal cells (SH-SY5Y) and neuroglia cells (C6), and its mechanism. We measured the production of NO-iNOS, TNF-${\alpha}$, and ICAM-1 using RT-PCR and Western blot analysis less than the concentration of cytotoxic effects (> 70% survivability). A${\beta}$ had no effect on the production of NO and TNF-${\alpha}$, but significantly increases of iNOS and ICAM-1. Based on this, we suggest that the inflammatory effect of A${\beta}$ results from the action of ICAM-1 in neuronal cells, rather than the release of inflammatory mediators such as NO and TNF-${\alpha}$ in neuroglia cells. In addition, we confirmed whether p53 was related to the action of A${\beta}$ by using SH-SY5Y ($p53^{-/-}$) dominant cells. Neither the expression of p53 nor the cytotoxicity of SH-SY5Y ($p53^{-/-}$) cells were directly affected by A${\beta}$. However, ICAM-1 was not expressed in SH-SY5Y ($p53^{-/-}$) cells. This means that p53- independent pathway exists in the expression of ICAM-1 by A${\beta}$ while p53 plays a role as an on-and-off switch.

• Journal of the Korean Society of Propulsion Engineers
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• v.20 no.6
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• pp.46-53
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• 2016

It is required to predict a limit cycle amplitude controlled by system's nonlinear behavior as well as an eigen-frequency and initial growth rate of instabilities under the linear motions, in order to fully understand combustion instabilities in a lean premixed gas turbine combustor. Special focus of the current work is placed on the limit cycle amplitude prediction using flame describing function(FDF) where the ratio of a heat release fluctuation to a given flow perturbation is expressed as a function of frequency and amplitude. In this study, the CFD modeling work based on RANS is carried out to obtain FDF, which makes that the nonlinear thermo-acoustic model is successfully developed for predicting the limit cycle amplitude of the combustion instability.

• Journal of the Society of Naval Architects of Korea
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• v.56 no.5
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• pp.418-426
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• 2019

To derive a simplified analytic solution which can be utilized as a fundamental solution for the wave maker design, a segment of the wave board has been idealized as a submerged line segment in a two dimensional domain of a wave flume. The lower end of the line segment could be located at arbitrary depth of the wave flume and the upper end of the board could be also submerged to any depth from the free surface. The freely oscillating motion of the wave board is assumed to be defined by determining the condition of horizontal oscillation on both ends differently. The submerged wave board oscillating in horizontal direction could be specified by selecting the amplitude, frequency and the phase lag differently on lower and upper ends of the board. The simplified two dimensional wave generated by the wave board segment has been obtained by the first order perturbation method. It is found that the general solution of the freely oscillating wave board in two dimensional domain could be decomposed into the solution of flap motion with lower end hinge and swing motion with upper end hinge. The case study of the analytic solutions has been carried out to evaluate the effect on the wave height due to the difference of oscillation frequency, phase difference and variation of stroke between for the motion of both ends. It is found that the solution of the freely oscillating wave board could be utilized for the development of high performance wavemaker especially for irregular waves.

• Journal of the Korean Dietetic Association
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• v.19 no.1
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• pp.1-13
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• 2013

The purpose of this study was to determine the optimal mixing condition of tomato powder and sugar for producing chiffon cake. The experiment was designed according to the central composite design of response surface, which yielded ten experimental points, including two replicates. Physiochemical and sensory properties were measured, and theses values applied to mechanical models. A canonical form and perturbation plot showed the influence of each ingredient on the final product mixture. The results of the physiochemical analysis of each sample showed significant differences in sweetness (P<0.01), color L (P<0.001), color a (P<0.001), color b (P<0.05), hardness (P<0.05), and cohesiveness (P<0.01). The sensory measurements were significantly different in color (P<0.05), appearance (P<0.05), flavor (P<0.05), sweetness (P<0.01), moistness (P<0.05), and overall acceptability (P<0.05). The optimal formulation, calculated using the numerical and graphical method, was determined to be 59.27 g tomato powder and 285.66 g sugar. The sensory evaluation showed significantly higher preferences in the color, flavor, appearance, texture, sweetness, tenderness, moistness and overall quality of the optimized chiffon cake compared to the controlled chiffon cake. The optimized chiffon cake also showed a high antioxidative activity compared to the controlled chiffon cake. Our results show that chiffon cake prepared with tomato powder enhances sensory characteristics and antioxidative activity.

• Korean journal of food and cookery science
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• v.24 no.1
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• pp.76-83
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• 2008

The aim of this study was to use arrowroot powder to develop a recipe for a nutritional cookie having the optimal composition of ingredients and texture to elict a strong preference response in all age groups. Wheat flour was partially substituted with arrowroot powder to reduce the wheat flour content of the cookie. Measurements were made and analyzed according to the Response Surface Methodology technique, which showed 16 experimental points including 2 replicates for arrowroot powder, yellow sugar and butter. The compositional and functional properties of the test were measured, and the values obtained were applied to a mathematical model. A canonical form and perturbation plot showed the influence of each ingredient on the final mixture product. The result of sensory evaluation showed very significant values for color (p<0.01), appearance (p<0.001), texture (p<0.05), overall quality (p<0.05), and flavor (p<0.05). Instrumental analysis showed significant values for lightness (p<0.001), redness (p<0.01), yellowness (p<0.01) and spread ratio (p<0.001). The optimal sensory ratios were determined to be 15g for the arrowroot powder, 70 g for sugar and 80 g for butter.