• The Korean Journal of Physiology and Pharmacology
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• v.2 no.3
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• pp.369-376
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• 1998

This report shows that hydroxyl radical, generated by a Fenton reaction involving adenosine $5'-diphosphate/Fe^{2+}$ complex ($5-15\;{\mu}M$) and $H_2O_2$ ($2\;{\mu}M$), induced differentiation of HL-60 cells in a dose- and time-dependent manner. This is evidenced by the increases in 12-O-tetradecanoylphorbol 13-acetate- and fMLP-stimulated superoxide production capability. The cells exposed to hydroxyl radical for defined periods (24∼96 hr) continued to differentiate even after the hydroxyl radical generating system had been removed. The differentiated cells displayed fMLP-stimulated calcium mobilization and increased expression of myeloid-specific antigen CD11b and CD14. The extent of the differentiation was markedly reduced by desferrioxamine ($100\;{\mu}M$), dimethylthiourea (5 mM), N,N'-diphenyl-1,4-phenylenediamine ($2\;{\mu}M$), and N-acetyl-L-cysteine (5 mM). The induction of differentiation by hydroxyl radical was enhanced by 3-isobutyl-1-methylxanthine ($200\;{\mu}M$) and Ro-20-1724 ($8\;{\mu}M$), and inhibited by dipyridamole (2 ${\mu}M$). These results suggest that hydroxyl radicals may induce commitment of HL-60 cells to differentiate into more mature cells of myelomonocytic lineage through specific signal-transduction pathway that is modulated by phosphodiesterase inhibitors.

• IE interfaces
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• v.24 no.1
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• pp.1-7
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• 2011

The purpose of this research was to develop an integrated interface for the usability test of systems or products in the design process. It is capable of automatically creating GOMS models which can predict human task performances. It can generate GOMS models to be interacted with the prototype interfaces. It can also effectively manage various design information and various usability test results to be implemented into the new product and/or system design. Thus we can perform usability test for products or system prototypes more effectively and also reduce time and effort required for this test. For usability tests, we established an integrated interface based on GOMS model by the LabVIEW program. We constructed the system that the linkage to GOMS model is available. Using this integrated interface, the menu structure of mobile phone can be constructed easily. User can design a depth and a breath that he want. The size of button and the label of the button is changable. The path to the goal can be defined by the user. Using a designed menu structure, the experiment could be performed. The results of GOMS model and the actual time are presented. Besides, values of operators of GOMS model can be defined as the value that user wants. Using the integrated interface that we developed, the optimal menu structure deducted. The menu structure that user wants can be established easily. The optimal layout and button size can be decided by comparison of numerous menu structures. User can choose the method of usability test among GOMS model and empirical data. Using this integrated interface, the time and costs can be saved and the optimal menu structure can be found easily.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.06a
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• pp.108-108
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• 2007

Inkjet printing is a non-contact and direct writing associated with a computer. In the industrial field, there have been many efforts to utilize the inkjet printing as a new way of manufacturing, especially for electronic devices. The etching resist used in this process is an organic polymer which becomes solidified when exposed to ultraviolet lights and has high viscosity of 300 cPs at ambient temperature. A piezoelectric-driven ink jet printhead is used to dispense $20-40\;{\mu}m$ diameter droplets onto the copper substrate to prevent subsequent etching. In this study, factors affecting the pattern formation such as printing resolution, jetting property, adhesion strength, etching and strip mechanism, UV pinning energy have been investigated. As a result, microscale Etch resist patterning of printed circuit board with tens of ${\mu}m$ high have been fabricated.

• Journal of Welding and Joining
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• v.27 no.6
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• pp.31-35
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• 2009

When conducting CTOD test, especially in thick welded steel plate, fatigue pre-cracking occasionally failed to satisfy the requirements of standards thus making the test result invalid. Internally accumulated residual stress of test piece has been thought as one of the main reasons. The propagation of fatigue crack, started from the tip of machined notch, which might have propagated irregularly due to residual stress field. To overcome this kind of difficulty three methods to modify the residual stress are suggested in standard i.e. local compression, reverse bending and stepwise high-R ratio method. In this paper not only multi pass welding but also local pre-compressing process of thick steel plate has been simulated using finite element method for clarifying variation of internal welding residual stress. The simulated results show that welding residual stress is compressive in the middle section of the model and it is predominantly increased after machining the specimen. Comparing as-welded state all component of the welding residual stress changing to compressive in the tip of machine notch whereas residual stress of the outer area remain as tensile condition relatively. Analysis results also show that this irregular residual stress distribution is improved to be more uniformly by applying local compression.

• Biomolecules & Therapeutics
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• v.10 no.4
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• pp.240-245
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• 2002

Cancer metastasis represents the most important cause of cancer death and antitumor agents that may inhibit this process have been extensively pursued. Invasion and metastasis of malignantly transformed cells involve degradation of the extracellular matrix (ECM) components by matrix metalloproteinases (MMP), especially MMP-2 and -9. We previously showed that H-ras-induced invasive phenotype may involve MMP-2, rather than MMP-9, in MCF10A cells. In the present study, we investigated the chemopreventive effect of Aster, a widely used culinary vegetable in Korea. We screened twelve extracts from three Aster species (Aster scaber, Aster oharai and Aster glehni) for the inhibitory effect on MMP activities of H-ras MCF10A human breast epithelial cells. All of the extracts tested in this study efficiently inhibited the gelatinolytic activities of MMP-2 and MMP-9. A more prominent inhibition was observed in MMP-2 activity compared to MMP-9. Out of twelve extracts, eight extracts showed>90％ inhibition of MMP-2 activity in H-ras MCF10A cells while only one extract showed>90％ inhibition of MMP-9 activity. We selected three extracts (AO-3, AG-3 and AS-EA) for further studies since they exerted a marked inhibition in the ratio of MMP-2 to MMP-9. Treatment with AO-3, AG-3 and AS-EA in H-ras MCF10A cells caused a significant inhibition of invasive phenotype and migration, proving a chemopreventive potential of these extracts. Taken together, our results demonstrate that extracts of Aster effectively inhibit invasion and migration of highly malignant human breast cells, possibly via downregulation of MMP-2 and MMP-9.

• Journal of Preventive Medicine and Public Health
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• v.19 no.2 s.20
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• pp.184-192
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• 1986

Since the wide spread application of hyperbaric oxygenation in clinical setting, the problems of oxygen toxicity have been attracting a deep interest from the researchers on hyperbaric medicine as a practical issue. Among extensive research trials, the study on the protective agents against oxygen toxicity occupied one of the most challenging field. As the mechanisms of oxygen toxicity, the role of the oxygen free radicals produced by peroxidation process are strongly accepted by the leading researchers on oxygen toxicity, the probable protective effects of antioxidant against oxygen toxicity are sustaining a sufficient rationale. In this study, the author attempted to evaluate the effect of vitamin E as a protective agent against oxygen toxicity through the observation of death rate, convulsion rate, time to convulsion, and macroscopic and microscopic pathological changes of experimental rats exposed to 100% oxygen at 5 ATA for 120 minutes. The findings observed are as follows: 1) The death rate, convulsion rate, time to convulsion, organ/body weight ratio and microscopic pathological findings were identified as reliable objective and quantitative indices for oxygen toxicity. 2) Vitamin E showed excellent protective effects against CNS and pulmonary oxygen toxicity as a strong antioxidant. The most effective dose seemed to be around 400 mg/kg 3) The results of this study are supporting the oxygen free radical hypothesis on oxygen toxicity.

• Journal of Korea Society of Industrial Information Systems
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• v.25 no.5
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• pp.23-29
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• 2020

The National Institute of Agricultural Sciences of the Rural Developement Administration (NAS, RDA) is conducting various studies on various crops, such as monitoring the cultivation environment and analyzing harvested seeds for high-throughput phenotyping. In this paper, we propose a deep learning-based rice seed segmentation method to analyze the seeds of various crops owned by the NAS. Using Mask-RCNN deep learning model, we perform the rice seed segmentation from manually taken images under specific environment (constant lighting, white background) for analyzing the seed characteristics. For this purpose, we perform the parameter tuning process of the Mask-RCNN model. By the proposed method, the results of the test on seed object detection showed that the accuracy was 82% for rice stem image and 97% for rice grain image, respectively. As a future study, we are planning to researches of more reliable seeds extraction from cluttered seed images by a deep learning-based approach and selection of high-throughput phenotype through precise data analysis such as length, width, and thickness from the detected seed objects.

• Mycobiology
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• v.46 no.4
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• pp.407-415
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• 2018

Pheromone (PHB)-receptor (RCB) interaction in the mating pheromone response pathway of Lentinula edodes was investigated using synthetic PHBs. Functionality of the C-terminally carboxymethylated synthetic PHBs was demonstrated by concentration-dependent induction of a mating-related gene (znf2) expression and by pseudoclamp formation in a monokaryotic strain S1-11 of L. edodes. Treatment with synthetic PHBs activated the expression of homeodomain genes (HDs) residing in the A mating type locus, and of A-regulated genes, including znf2, clp1, and priA, as well as genes in the B mating type locus, including pheromone (phb) and receptor (rcb) genes. The synthetic PHBs failed to discriminate self from non-self RCBs. PHBs of the B4 mating type (B4 PHBs) were able to activate the mating pheromone response pathway in both monokaryotic S1-11 and S1-13 strains, whose B mating types were B4 (self) and B12 (non-self), respectively. The same was true for B12 PHBs in the B4 (non-self) and B12 (self) mating types. The synthetic PHBs also promoted the mating of two monokaryotic strains carrying B4-common incompatible mating types ($A5B4{\times}A1B4$). However, the dikaryon generated by this process exhibited abnormally high content of hyphal branching and frequent clamp connections and, more importantly, was found to be genetically unstable due to overexpression of mating-related genes such as clp1. Although synthetic PHBs were unable to discriminate self from non-self RCBs, they showed a higher affinity for non-self RCBs, through which the mating pheromone response pathway in non-self cells may be preferentially activated.

• Atmosphere
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• v.29 no.3
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• pp.269-282
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• 2019

While it is important to obtain the accurate information on snowfall data due to the increase in damage caused by the heavy snowfall in the winter season, it is not easy to observe the snowfall quantitatively. Recently, snow measurements using a weighing precipitation gauge have been carried out, but there is a problem that high snowfall intensity results in low accuracy. Also, the observed snowfall data are sensitive depending on wind speed, temperature, and humidity. In this study, a new process of quality control for snow water equivalent (SWE) data of the weighing precipitation gauge were proposed to cover the low accuracy of snow data and maximize the data utilization. Snowfall data (SWE) observed by Pluvio, Parsivel, snow-depth meter using laser or ultrasonic, and rainfall gauge in Cloud Physics Observation Site (CPOS) were compared and analyzed. Applying the QC algorithm including the use of number of hydrometeor particles as reference, the increased SWE per the unit time was determined and the data noise was removed and marked by flag. The SWE data converted by the number concentration of hydrometeor particles are tested as a method to restore the QC-removed data, and show good agreement with those of the weighing precipitation gauge, though requiring more case studies. The three events data for heavy snowfall disaster in Pyeongchang area was analyzed. The SWE data with improved quality was showed a good correlation with the eye-measured data ($R^2$ > 0.73).

• Journal of Applied Biological Chemistry
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• v.62 no.1
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• pp.93-100
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• 2019

The root of Panax ginseng is used in ethnomedicine throughout eastern Asia and various recent studies have proved that Panax ginseng has inhibitory effects on cardiovascular disease. Each factor causing cardiovascular disease is known to have a very complex process which is achieved by a diverse number of mechanisms. Among these factors, platelets are the most important because they directly participate in thrombogenesis. Therefore, inhibiting the activity of platelets is an essential element for prevention of cardiovascular diseases. Our previous study showed the antiplatelet effects of Korean red ginseng extract and two of its components, ginsenoside Rg3 and ginsenoside Ro. However, the inhibitory mechanism of other ginsenosides remains unclear. Therefore, we investigated the inhibitory mechanism of ginsenoside F4 (G-F4) from Korean red ginseng on the regulation of signaling molecules involved in human platelet aggregation. With the use of G-F4, collagen-induced human platelet aggregation was inhibited in a dose-dependent manner, and it suppressed collagen-induced elevation of $[Ca^{2+}]_i$ mobilization through elevated phosphorylation of inositol 1, 4, 5-triphosphate receptor I ($Ser^{1756}$). In addition, G-F4 inhibited fibrinogen binding to ${\alpha}IIb/{\beta}_3$ during collagen-induced human platelet aggregation. Thus, in the present study, G-F4 showed an inhibitory effect on human platelet activation, suggesting its potential use as a new natural medicine for preventing platelet-mediated cardiovascular diseases.