• KSBB Journal
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• v.7 no.4
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• pp.290-295
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• 1992

Reactive oxygen scavenging activity and immune stimulatory activity of lactobacilli were investigated by different free radical scavenging assays and Ig G assay. Lactobacilli culture (S/N) and its complex with $Mn^{2+}$ have significant effects in XOD assay and response to paraquat. Cell free extract significantly prevented the photohemolysis. Thus, it seems that each sample from lactobacilli has a different free radical scavening mechanism. Furthermore, it is assumed that cell free extract from lactobacilli activates antibody stimulation of B cell through a stimulation of T cell.

• Korean Journal of Plant Resources
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• v.26 no.5
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• pp.548-556
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• 2013

The objective of this study was to determine the effect of antioxidant enzyme activity and radical scavenging activities of cucumber grown greenhouse. The analytic method of antioxidant activities were measured by estimating DPPH free radical scavenging, nitrite scavenging ability activity and ABTS radical scavenging ability. The DPPH free radical scavenging activity of Jangjukcheongjang was the highest in most of the growth stage. The Nitrite scavenging ability at pH 1.2 was more than 40% in all cultivars and growth stages. The ABTS radical scavenging ability of Jangjukcheongjang and Nulpureuncheongjang showed relatively little higher than Janghyeongnakhap and Sinjoeunbaekdadagi. The SOD activity showed higher activity than 95% in all cultivars and growth stages. The activity of CAT was highest in the Nulpureuncheongjang of 2 (12~16cm) growth stage, and the APX activity of Nulpureuncheongjang and Janghyeongnakhap showed a relatively high activity. The POX activity showed distinctly different trends depending on the growth stage, and that is, the activity at harvest stage was significantly reduced. These results suggest that the cucumber had the potent biological activities, and that in the future, the availability of cucumber will be increase in the field of high-value cosmetic and food products.

• Food Science and Preservation
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• v.23 no.7
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• pp.989-994
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• 2016

As part of our continuing search for bioactive natural products, the antioxidant and ${\alpha}$-glucosidase inhibitory activities of an 80% methanolic extract and organic solvent soluble-portions of Aruncus dioicus var. kamtschaticus roots were investigated by using a bioassay system. The antioxidant activity of A. dioicus var. kamtschaticus roots extract and organic solvent soluble-portions were assessed by examining with 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid) ($ABTS^+$) radical scavenging. In addition, anti-diabetic effects of the A. dioicus var. kamtschaticus root extract and organic solvent soluble-portions were tested via ${\alpha}$-glucosidase inhibition assay. The total phenolic contents of the products were determined by applying UV-VIS spectrophotometry. All tested samples showed dose-dependent radical scavenging and ${\alpha}$-glucosidase inhibitory properties. In particular, the ${\alpha}$-glucosidase inhibitory and radical scavenging effects of the ethyl-acetate (EtOAc)-soluble portion from the roots of A. dioicus var. kamtschaticus were greater than those from other solvent-soluble portions. These results indicate that A. dioicus var. kamtschaticus could be considered a new effective source of natural antioxidants and anti-diabetic materials. More systematic research of the constituents of the roots of this A. dioicus variety will be conducted to further develop its antioxidative and anti-diabetic properties.

• Korean Journal of Organic Agriculture
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• v.26 no.3
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• pp.477-488
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• 2018

This study examined the total phenolic and flavonoid compounds, and the antioxi dant activity of major cultivars of Prunus mume in Korea. The total phenolic content ranged from 64.13 to $93.43mg{\cdot}100g^{-1}$, with the content in 'Osuku' being higher than that in the other cultivars; a difference in the content among cultivars was observed. The total flavonoid content was $6.16{\sim}18.57mg{\cdot}100g^{-1}$, showing a significant difference, with the highest content being noted in 'Gojirou'. The DPPH radical scavenging activity was measured and was relatively high for Nanko, Kamakami, Natsuka, Dana, and Osuku cultivars. When ABTS radical scavenging activity was measured, all the cultivars showed a scavenging activity over 80%, with the scavenging activity of 'Osuku' being the highest. With respect to nitrite scavenging ability, all cultivars exhibited a high scavenging activity of over 50%, with the highest activity observed for 'Nanko' (76.03%), 'Gojirou' (70.56%), and 'Yourou' (70.32%). Based on the study results, it is considered that Prunus mume can be a useful resource because of various substances with functional physiological activities.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.5
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• pp.911-916
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• 2016

The nearest-neighbor multihop routing with/without infrastructure support is known to achieve the optimal capacity scaling in a large packet-erasure network in which multiple wireless nodes and relay stations are regularly placed and packets are erased with a certain probability. In this paper, a throughput scaling law is shown for an infrastructure-supported erasure network where wireless nodes are randomly distributed, which is a more feasible scenario. We use an exponential decay model to suitably model an erasure probability. To achieve high throughput in hybrid random erasure networks, the multihop routing via highway using the percolation theory is proposed and the corresponding throughput scaling is derived. As a main result, the proposed percolation highway based routing scheme achieves the same throughput scaling as the nearest-neighbor multihop case in hybrid regular erasure networks. That is, it is shown that no performance loss occurs even when nodes are randomly distributed.

• Journal of the Korean Institute of Telematics and Electronics D
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• v.36D no.6
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• pp.21-27
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• 1999

In this work, single-poly EEPROM was designed and fabricated by using standard $0.8{\mu}m$ CMOS process. From the results of programming and erasing characteristics, it was found that the programming time was smaller than 10ms and the erasing time was about 100ms. To reduce the erasing time, several erasing methods were performed. The S/D erasing method was used to improve the endurance characteristics which was degraded due to electron trapping in programming and erasing cycles. By using the S/D erasing method, the more improved endurance characteristics then conventional one was obtained.

• Korean Journal of Food Science and Technology
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• v.20 no.3
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• pp.453-458
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• 1988

This research was carried out to investigate the effects of Maillard reaction products and nondialyzable melanoidins on the nitrite-scavenging. Nitrite-scavenging reactions were done at the different pH conditions(pH 1.2, 4.2 and 6.0). Maillard reaction products and nondialyzable melanoidins, produced from the glucose-amino acids(lys., gly., arg., his.)model systems, had a great of nitrite-scavenging effects. Nitrite-scavenging effects of Maillard reaction products and nondialyzable melanoidins were also pH dependent, being higher at pH 1.2 and lower at pH 6.0. By the treatment of Maillard reaction products and nondialyzable melanoidins with sodium borohydride, nitrite-scavenging effects were remarkably decreased at pH 1.2.

• Food Science and Preservation
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• v.9 no.2
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• pp.253-259
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• 2002

The antioxidative and free radical scavenging activity of water extracts of dandelion were investigated. Antioxidative and radical scavenging activity were assessed by means of different tests; inhibition of peroxidation on linoleic acid model system, scavenging DPPH radical, scavenging of hydroxyl radical by chemiluminescence assay, scavenging of superoxide anion radical by EPR spectroscopy and scavenging of hydrogen peroxide. The leaf extract showed strong antioxidant activity in linoleic acid system. The antioxidant activity of water extracts of dandelion increased with increasing concentrations of extracts. The scavenging activity of the dandelion extracts, on inhibition of the DPPH radical, was related to the reaction time. Hydroxyl radical were generated by lenten reaction and dandelion extract was found to scavenge OH˙in a concentration-dependent manner. The water extract of leaf had effective scavenging activities on hydrogen peroxide and superoxide anion radical. From the these data, it is evident that water extract of dandelion leaf is an effective scavenger for OH˙, O$_2$¨, DPPH˙, hydrogen peroxide. And, the antioxidative effect observed is believed to be partly due to this radical scavenger activity.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2021.04a
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• pp.64-64
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• 2021

색과 향과 맛 및 기능성까지 뛰어난 대표적인 꽃차가 백목련이나 기능성에 관한 연구는 아직 매우 미미하다. 본 연구에서는 유리산소 소거능(DPPH)와 아질산염 소거능(Nitrite Scavenging Activity)이 백목련 꽃차가 제조된 2017년부터 2021년까지의 연도에 따라서 차이가 있는 지를 알아보고자 수행하였으며 그 결과는 다음과 같았다. 1. DPPH는 측정농도(0.5g/100ml=500ppm)에서 제조연도가 2017년 것은 87.8±0.0, 2018년 것은 87.5±0.1, 2019년 것은 85.6±0.6, 2020년 것은 88.5±0.2, 2021년 것은 86.1±0.1으로 2020년에 제조한 것이 가장 높은 함량을 보였다. RC50이란 소거능력이 50%를 환원시킬 수 있는 환원율을 의미하며 낮을수록 적은 양으로 환원이 가능하여 함량이 높다고 할 수 있으며 RC50값은 2017년이 140,2, 2018년이 165.0, 2019년이 178.6, 2020년이 112.2, 2021년이 151.4으로 2020년이 가장 뛰어난 활성을 보였다. 2. 아질산염 소거능은 측정농도(0.5g/100ml=500ppm)에서 제조연도가 2017년 것은 31.8±1.9, 2018년 것은 21.1±4.6, 2019년 것은 18.2±1.9, 2020년 것은 31.0±1.4, 2021년 것은 19.3±5.7의 수치를 보여 2017년과 2020년이 높은 활성을 보였다.

• The Journal of the Korea institute of electronic communication sciences
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• v.19 no.1
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• pp.113-118
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• 2024

In this paper, we propose an optimal wavelet in a system for canceling background noise of acoustic signals. This system performed Discrete Wavelet Transform(DWT) instead of the existing Short Time Fourier Transform(STFT) and then improved noise cancellation performance through a deep learning process. DWT functions as a multi-resolution band-pass filter and obtains transformation parameters by time-shifting the parent wavelet at each level and using several wavelets whose sizes are scaled. Here, the noise cancellation performance of several wavelets was tested to select the most suitable mother wavelet for analyzing the speech. In this study, to verify the performance of the noise cancellation system for various wavelets, a simulation program using Tensorflow and Keras libraries was created and simulation experiments were performed for the four most commonly used wavelets. As a result of the experiment, the case of using Haar or Daubechies wavelets showed the best noise cancellation performance, and the mean square error(MSE) was significantly improved compared to the case of using other wavelets.