• Clinical and Experimental Pediatrics
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• v.52 no.6
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• pp.696-700
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• 2009

Purpose : We screened more than 350 compounds with an endoperoxide ring structure in search of an anti-leukemic drug and found that compound 127 (c-127) could induce significant cytotoxicity in HL-60 cells. In this study, we investigated the molecular mechanisms of compound 127-induced antitumor activity on HL-60 cells. Methods : HL-60 cells were cultured in Rosewell Park Memorial Institute 1640 and cell viability was measured by MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide], a tetrazole assay. Apoptosis was assessed by a DNA fragmentation test. Apoptotic machineries were determined by Western blot analysis. Results : C-127 could induce a cytotoxic effect at 24 h and apoptosis at 6 h, which was demonstrated with MTT assay and DNA fragmentation test, respectively. The apoptotic effect of this drug was caused by the activation of the intracellular caspase-8,3 activation, the cleavage of pro-apoptotic Bid, and the increase of c-Jun expression accompanied with JNK (Jun N-terminal kinases) phosphorylation. On the contrary, it increased the expression of anti-apoptotic Bcl-2 levels, leading to the induction of the induction of anti-apoptotic effect. Taken together, the present study demonstrated that c-127 was a potent inducer of cytotoxicity on HL-60 cells through apoptotic mechanisms, which included the activation of caspase family, the regulation of Bcl-2 family, and the activation of JNK signaling pathway. Conclusion : Our results suggest that c-127 has a strong antitumor activity through the regulation of various apoptotic machineries on HL-60 cells. The compound may be utilized as an effective and potentially therapeutic drug in leukemia.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.33A no.11
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• pp.1-9
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• 1996

In the following paper, new architectural algorithm of clock and data recovery circuit is proposed for 622.08 Mbps optical communication receiver. New algorithm makes use of charge pump PLL using voltage controlled ring oscillator and extracts 8-channel 77.76 MHz clock signals, which are delayed by i/8 (i=1,2, ...8), to convert and recover 8-channel parallel data from 662.08 Mbps MRZ serial data. This circuit includes clock genration block to produce clock signals continuously even if input data doesn't exist. And synchronization of data and clock is doen by the method which compares 1/2 bit delayed onput data and decided dta by extracted clock signals. Thus, we can stabilize frequency and phase of clock signal even if input data is distorted or doesn't exist and simplify receiver architecture compared to traditional receiver's. Also it is possible ot realize clock extraction, data decision and conversion simulataneously. Verification of this algorithm is executed by DESIGN CENTER (version 6.1) using test models which are modelized by analog behavior modeling and digital circuit model, modified to process input frequency sufficiently, in SPICE.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2004.11a
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• pp.166-172
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• 2004

An underwater motion measurement system was constructed for applications to the model basin. A commercial motion capture system, FALCON of Motion Analysis Corp., which corrects automatically the distortion caused by refraction of the light passing through water and air, was adopted for underwater motion measurement. The modifications of FALCON system were performed: waterproofing camera housings, markers, connectors, and a new blue ring lighter. the accuracy of the motion measurement was obtained within the calibration error of 0.87mm in average and 0.89mm in standard deviation for the distance of 500mm between two markers on the calibration device. the volume of $2100mm(length)\times2100mm(breadth)\times2300mm(Height)$ was covered with 4 cameras of the underwater motion measurement system. For the performance verification, motion measurement test of a vertical mooring chain model excited at the top end was carried out. The 3D motions of mooring model were measured with variable amplitude and period of the forced excitation. Higher order motions of the mooring model were observed as the excitation period decreases. the performance of the system was verified by successfully measuring 3D motion of mooring model.

• Advances in concrete construction
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• v.14 no.2
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• pp.139-151
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• 2022

Filling materials poured into precast member joint are subjected to restraint stress by the precast member and joint reinforcement. The induced stress will likely cause cracks at early ages and performance degradation of the entire structure. To prevent these issues and design reasonable joints, it is very important to analyze and evaluate the restrained shrinkage cracks of filling materials at various restraint conditions. In this study, a new time zero-that defines the shrinkage development time of a filling material-is proposed to calculate the accurate amount of shrinkage. The tensile stresses and strengths at different ages were compared through the ring test (AASHTO PP34) to evaluate the crack potential of the restrained filling materials at various restraint conditions. The mixture which contained an expansive additive and a shrinkage reducing agent exhibited high resistance to shrinkage cracking owing to the high-drying shrinkage compensation effect. The high-performance, fiber-reinforced cement composite, and ultra-high-performance, fiber-reinforced cement composite yielded very high resistance to shrinkage and cracking owing to the pull-out property of steel fibers. To this end, multiple nonlinear regression analyses were conducted based on the test results. Accordingly, a modified tensile stress equation that considered both the geometric shape of the specimen and the intrinsic properties of the material is proposed.

• Journal of the Korean Chemical Society
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• v.54 no.1
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• pp.77-87
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• 2010

Hospital-acquired methicillin-resistant Staphylococcus aureus (MRSA) has been an increasing problem worldwide since the initial reports over 40 years ago. To examine new drug leads with potential antibacterial activities, Various N'-[(-3-substituted-4-oxo-1,3-thiazolidin-2-ylidene]-4-hydroxy benzohydrazide (4a-4.i) and N'-[-(3,4-disubstituted)-1,3-thiazolidin-2ylidene)]-4-hydroxybenzohydrazide from (5.a-5.i) to (10.a-10.i) were synthesized using appropriate synthetic route. The entire test compounds (4.a-4.i) and from (5.a-5.i) to (10.a-10.i) were assayed in vitro against s. aureus strain. The minimum inhibitory concentration (MIC) was determined for test compounds and for reference standards. The test compounds showed significant antibacterial activity against the strains used, when tested in vitro. In general, p-hydroxybenzohydrazide ring and substituted thiazoline ring are essential for antimicrobial activity. Among the compounds tested, compounds 6.f, 7.g, 9.f and 10.f, 10 i were found to be most potent. The test compounds were found nontoxic upto the dose level of 2000 ${\mu}g$/mL. The intact compounds were then subjected for 3D-QSAR studies. 3D-QSAR study based on the principal of alignment of pharmacophoric features by Schrodinger PHASE module. The 3D-QSAR study allowed us to confirm the preferential binding mode of p-hydroxybenzohydrazide inside the active site.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.11C
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• pp.1044-1051
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• 2006

System level diagnosis algorithms use the properties of t-diagnosable system where the maximum number of the faults does not exceed 1. The existing diagnosis algorithms have limit when dealing with large fault sets in large multiprocessor systems. Somani and Peleg proposed t/k-diagnosable system to diagnose more faults than t by allowing upper bounded few number of units to be diagnosed incorrectly. In this paper, we propose adaptive hypercube diagnosis algorithm using t/k-diagnosable system. When the number of faults exceeds t, we allow k faults to be diagnosed incorrectly. Simulation shows that the performance of the proposed algorithm is better than Feng's HADA algorithm. We propose new algorithm to reduce test rounds by analyzing the syndrome of RGC-ring obtained in the first step of HADA/IHADA method. The proposed algorithm also gives similar performance compared to HYP-DIAG algorithm.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.22 no.2
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• pp.33-37
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• 2016

One-way degassing valves usually designed for coffee packaging are recently applied to the various food packaging such as fermented health functional food or home meal replacement (HMR) packaging. The optimized degassing pressure by food product is important factor for keeping effective freshness and improving preservation of the food, therefore the development of degassing valves specified with various open pressure is needed. In this study, the mechanical characteristics of the degassing valve with ring type rubber disk were analyzed and a mathematical model was developed to predict the open pressure of the valve. The model was verified with test results derived from several available valves, and it may be useful in designing and developing a new valve.

• Polymer(Korea)
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• v.29 no.3
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• pp.314-319
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• 2005

Four kinds of new aliphatic diols were synthesized by the ring opening reaction of glycolide with 1,4-butanediol, 1,6-hexanediol, 1,4-cyclohexanediol, or 1,4-cyclohexanedimethanol, a difunctional initiator, in the presence of stannous octoate catalyst. The resulting diols were melt-polymerized with succinic acid, adipic acid, or suberic acid at 170, 190, or $220^{circ}C$ to produce new sequentially ordered aliphatic polyesters and their corresponding polyesters with random structure. Their glass transition temperatures ($T_g$) ranged from -40 to $30^{circ}C$, The sequentially ordered polyesters prepared at $170^{cir}C$ had higher $T_g$ of 5 to $10^{circ}$ than the polyesters with rand()m structure produced at higher temperature. From in-vitro degradation test the sequentially ordered polyesters was shower in the rate of hydrolysis in a buffer solution than the polymers with random molecular structure.

• Journal of Ocean Engineering and Technology
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• v.29 no.2
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• pp.191-198
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• 2015

In this study, we proposed a new type of dual-buoy wave energy converter (WEC) exploiting multi-resonance and analyzed the experimental results from a model test in a 2-D wave flume. A dual-buoy WEC using multi-resonance has two advantages: high efficiency at the resonant frequencies and the potential to extend the frequency range available to extract wave power from the WEC. The suggested WEC was composed of an outer buoy and an inner buoy sliding vertically inside the outer buoy. As the power take-off device, a linear electric generator (LEG) consisting of permanent magnets and coils fixed at each buoy was adopted. Electricity was produced by the relative heave motion between the two buoys. To search for the optimal shape of a dual-buoy WEC, we conducted experiments on the heave motion of a two-body system in regular waves without an LEG installed. Model tests with six combinations of experimental models were conducted in order to find the motion characteristics of a dual-buoy WEC. It was found that model 2, which included a ring-shaped appendage to move the resonant frequency of the outer buoy toward a high value, showed a higher relative heave response amplitude operator (RAO) curve than model 1. In addition, the double-peak shape of the heave RAO curve shown for model 2 indicated the extension of the frequency range for extracting wave power in irregular waves.

• Journal of the Korean Ceramic Society
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• v.26 no.2
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• pp.187-194
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• 1989

Synthesis of spinel pigment on ZnO-Fe2O3 system. The object of this research is the synthesis of new spinel pigments on the basic of ZnO-Fe2O3 system which was substituted by ZnO-Fe2O3 by MgO-Al2O3. This research was progressed by measuring the X-ray diffraction and the reflectances of the substitued ZnO-Fe2O3 group. Which was obtained by sintering at the temperature of 1,00$0^{\circ}C$, 1,10$0^{\circ}C$, 1,20$0^{\circ}C$ and 1,25$0^{\circ}C$ and them by regrinding. In order to coloring test, here basic compositions of Barium glaze, Zinc glaze, Lime glaze, Lead glaze and Talc glaze used in this experiment are obtained from the ceramic work. Adding synthetic stains in these basic glazes with 3%, mixing and glazing on the specimen. The specimens was fired at 1,28$0^{\circ}C$ in reducing and oxidizing atmosphere in the gas kiln. The results of the research as follow. 1. Many kinds of spinel pigment was produced on ZnO-Fe2O3 system that is to say, not always only spinel. 2. Spinel peak was observed strongly on the ZnO-Fe2O3 system withsubstituting by MgO-Fe2O3 and MgO-Al2O3 group(the ratio of MgO, Al2O3 being increased, observed more strongly). 3. The most effective temperature ranges was 1,20$0^{\circ}C$~1,25$0^{\circ}C$. 4. The color of spinel pigments on this system was observed by "stable YR". 5. It was yellow red in oxidizing and green in reducing atmosphere on the coloring test.ring test.