• JSTS:Journal of Semiconductor Technology and Science
• /
• v.14 no.5
• /
• pp.640-648
• /
• 2014

Excessive power dissipation is one of the major issues in the testing of VLSI systems. Many techniques are proposed for scan test, but there are not so many for logic BIST because of its unmanageable randomness. This paper presents a novel low switching activity BIST scheme that reduces toggle frequency in the majority of scan chain inputs while allowing a small portion of scan chains to receive pseudorandom test data. Reducing toggle frequency in the scan chain inputs can reduce test power but may result in fault coverage loss. Allowing a small portion of scan chains to receive pseudorandom test data can make better uniform distribution of 0 and 1 and improve test effectiveness significantly. When compared with existing methods, experimental results on larger benchmark circuits of ISCAS'89 show that the proposed strategy can not only reduce significantly switching activity in circuits under test but also achieve high fault coverage.

• Fisheries and Aquatic Sciences
• /
• v.25 no.6
• /
• pp.335-349
• /
• 2022

To optimize the hydrolysis conditions in the production of antioxidant hydrolysates from tuna cooking juice concentrate (TC) to maximize the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity, TC containing 48.91% protein was hydrolyzed with Alcalase 2.4 L, and response surface methodology (RSM) was applied. The optimum hydrolysis conditions included a 2.2% (w/v) Alcalase concentration and 281 min hydrolysis time, resulting in the highest DPPH radical scavenging activity of 66.49% (0.98 µmol Trolox/mg protein). The analysis of variance for RSM showed that hydrolysis time was an important factor that significantly affected the process (p < 0.05). The effects of different drying methods (freeze drying, hot air drying, and vacuum drying) on the DPPH radical scavenging activity and amino acid (AA) profiles of TC hydrolysate (TCH) were evaluated. Vacuum-dried TCH (VD) exhibited an increase in DPPH radical scavenging activity of 81.28% (1.20 µmol Trolox/mg protein). The VD samples were further fractionated by ultrafiltration. The AA profiles and antioxidant activities in terms of the DPPH radical scavenging activity, 2,2'-azino-bis(3-ethylbenzthiazoline)-6-sulfonic acid (ABTS) radical scavenging activity, ferric reducing antioxidant power, and ferrous ion chelating activity were investigated. Glutamic acid, glycine, arginine, and cysteine were the major AAs found in the TCH fractions. The highest DPPH radical scavenging activity was found in the VD-1 fraction (< 5 kDa). The VD-3 fraction (> 10 kDa) exhibited the highest ABTS radical scavenging activity and ferric reducing antioxidant power. The ferrous ion chelating activity was the highest in VD-1 and VD-2 (5 to 10 kDa). In conclusion, this study provided the optimal conditions to obtain high antioxidant activities through TCH production, and these conditions could provide a basis for the future application of TCH as a functional food ingredient.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.44 no.5
• /
• pp.695-701
• /
• 2015

This study was conducted to evaluate the effects of drying and extraction methods on antioxidant activity and total phenol content of Gnaphalium affine D. DON (GA). Hot-air, shade-drying, and freeze-drying were used for drying, after which magnetic stirring and ultrasonification were applied. Extracting solvents were water, 80% ethanol, and 80% methanol. Total phenol content was highest in 80% ethanol extract of freeze-dried and stirred GA. Total flavonoid content was highest in 80% methanol extract of freeze-dried and stirred GA. 2,2-Diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity was higher in 80% methanol and 80% ethanol extracts than in water extract. 2,2-Azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) radical scavenging activity was highest in 80% ethanol extract of shade-dried and ultrasonicated GA. Reducing power was generally higher in 80% methanol extract than in 80% ethanol and water extracts of GA. Total phenol and total flavonoid contents were highly correlated with DPPH radical scavenging activity and reducing power, respectively. This result implies that the antioxidant activity of GA can be attributed to phenol compounds such as flavonoids. Conclusively, phenol compounds such as flavonoids are responsible for the antioxidant activity of GA, and there was no significant effect of drying and stirring conditions on antioxidant activity of 80% ethanol. Meanwhile, DPPH radical scavenging activity of water extract and reducing power of 80% methanol extract were higher in hot-air and shade-dried GAs than in freeze-dried GA.

• The Korea Journal of Herbology
• /
• v.32 no.5
• /
• pp.19-25
• /
• 2017

Objective : The Sinseon-yukza-hwan (SSY), a Korean medicinal formula which includes Radix Rehmanniae Preparata and other medicinal herbs, has long been used for treatment of alopecia and gray hair through oral administration. This study is designed to enhance the utilization of natural materials in hair and scalp-related cosmetics. Possibility of SSY as an antioxidant was examined from its 50% ethanol extract. Methods : The antioxidative capacities were evaluated by determining total phenolic and flavonoid contents, 1,1-diphenyl-2-picryl hydrazyl (DPPH), 2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), reducing power and hydroxyl radical scavenging activity. Results : Total polyphenol and flavonoid contents of SSY were 25.53 mg TE, tannic acid equivalent/g and 18.90 mg RE, rutin equivalent/g, respectively, which correlated strongly its antioxidative activity. The DPPH and ABTS free radical scavenging activities of SSY at $0.1mg/m{\ell}{\sim}5mg/ml$ were ranged from 20% to 85% and 10% to 58%, respectively. Also the hydroxyl radical scavenger activity and reducing power increased in SSY-treated group, which were significantly lower in SSY-compared to BHA-treated group. But the highest reducing power was shown as 79% from SSY-treated group, which was higher value than 65% from BHA-treatment. These results showed that SSY extract effectively inhibited the generation of free radicals in the all assay system with dose-dependent manners. Conclusions : Thus, the present study provide preclinical data to support the expanded application of SSY, which could be potential candidates for natural antioxidants.

• Journal of Mushroom
• /
• v.18 no.3
• /
• pp.244-253
• /
• 2020

The aim of this study was to investigate the biological activity of extracts obtained from the mycelium, sclerotium, and fruiting body of Wolfiporia cocos using different extraction solvents (hot water, 70% ethanol, and 70% methanol). Among the three developmental stages, the mycelium extracts showed the highest DPPH (2,2-diphenyl-1-picrylhydrazyl) radical scavenging activity, ferric reducing antioxidant power (FRAP), nitrite scavenging activity, and total polyphenolic content. Among the extraction solvents in the context of the W. cocos mycelium, the DPPH radical scavenging activity, FRAP, and total polyphenol content in the hot-water extracts were significantly higher than those in the other extracts. In the case of the sclerotium, the reducing power, nitrite scavenging activity, and total polyphenol content were significantly higher in 70% ethanolic extracts. The fruiting body showed the highest DPPH radical scavenging activity, reducing power, nitrite scavenging activity, and total polyphenol content in the context of hot-water extraction. Moreover, the β-glucan content was significantly higher in the sclerotium versus the mycelium or fruiting body. The total amino acid and total essential amino acid contents were remarkably higher in the mycelium and fruiting body than in the sclerotium; of note, and arginine (Arg) and phenylalanine (Phe) were highly detected among the amino acid components.

• Korean Journal of Medicinal Crop Science
• /
• v.18 no.4
• /
• pp.217-223
• /
• 2010

In this study, we investigated antioxidant capacity and determined the phenolic and flavonoid contents using each of various solvent conditions from fermented Rhus verniciflua stem bark (F-RVS). Each extracts displayed markedly similar content of extraction yield. However, M80 extract showed a significantly higher antioxidant activity in comparison to other extract investigated. M80 exhibited strong DPPH radical scavenging activity with $RC_{50}$ value of $10.5{\pm}1.4{\mu}g/m{\ell}$, reducing power value 1.04 Abs (concentration of 1 mg/$m{\ell}$), and anti-lipid peroxidation activity value of 94.6% (concentration of 10 mg/$m{\ell}$). M80 extract showed the high content of total phenolic (319.7 mg GAE/$m{\ell}$ extract) and total flavonoid (111.6 mg QE/$m{\ell}$ extract). Phenolic and flavonoid compounds showed significant relationship in DPPH radical scavenging ($R^2$=0.911 and 0.912, each extract) and reducing power ($R^2$=0.903 and 0.837, each extract) from fermented R. verniciflua stem bark. However, antilipid peroxidation activity ($R^2$=0.589 and 0.441, each extract) was not significant like DPPH radical scavenging and reducing power. Therefor the result indicated that the potential antioxidant activities and functional values were ovserved significantly at M80 solvent condition from the fermented R. verniciflua stem bark.

• Journal of the Korean Applied Science and Technology
• /
• v.35 no.3
• /
• pp.622-632
• /
• 2018

The aim of the present study was to evaluate of turmeric (Curcuma longa L.) on the physiological activities and oxidation inhibitory action. The effects of various solvents (distilled water DW, 70% ethanol and n-butanol) on the total phenolics content (TPC) of turmeric and their corresponding biological activity were studied. Bioactive compound of total saponin $7.506{\pm}0.349mg\;SE/g$ dry weight. Turmeric extracts yield were DW (17.11%), 70% ethanol (15.26%) and n-butanol (4.12%), respectively. Oxidation inhibitory action of the samples exhibited a dose-dependent increase. However, in the current study, none of the samples evaluated showed activity as strong as the BHA, ascorbic acid and EDTA. Results showed that extraction solvent had significant effects on TPC and oxidation inhibitory action (DPPH radical scavenging activity, ABTS radical scavenging activity, reducing power and ferric reducing antioxidant power) of n-butanol. Turmeric exhibited the antioxidant properties, which suggests that the plant material could be used for further studies as a potential source for bioactive and natural antioxidant.

• Food Science and Preservation
• /
• v.18 no.1
• /
• pp.59-64
• /
• 2011

This study was performed to investigate antioxidant activity of various solvent extracts (methanol, ethanol, acetone and water) from canola meal. As the concentration of all extracts increased, antioxidant activities increased gradually. Among solvent extracts from canola meal, methanol extract showed the highest antioxidant activities with $EC_{50}$ values of 0.9, 3.5, 1.3, and 8.5 mg/mL for DPPH radical scavenging ability, ABTS radical scavenging ability, reducing power, and chelating ability, respectively, and it had the highest total phenolics and total flavonoids contents. Furthermore, methanol extract was fractionated into three fractions (MF 1, MF 2, and MF 3) using Sephadex LH-20 column. The highest antioxidant activity was found on MF 2 for DPPH radical scavenging ability, on MF 3 for ABTS radical scavenging ability and reducing power, and on MF 1 for chelating ability at the same concentration of 1.5 mg/mL. The results indicated that each fraction containing various antioxidant materials seemed to have different influence at each antioxidant activity.

• Journal of Life Science
• /
• v.22 no.11
• /
• pp.1507-1514
• /
• 2012

Oxidative stress leads to damage in all components of the cell, including proteins, lipids, and DNA due to imbalance between reactive oxygen species production and cellular detoxification. Phytochemicals are well-known to contain antioxidants, and their physiological role has been intensively studied. The fruit of Cornus officianalis has been used in oriental medicine and has been reported to have many functions. In this study, four different extraction techniques were applied to extract functional components from the fruit of Cornus officianalis, and the content of loganin, which is an antioxidant having DPPH radical and hydrogen peroxide scavenging activity and reducing power, was analyzed in each extract. Extraction techniques employed in this study were heat extraction by water, 70% ethanol extraction, enzyme treatment, and combination of enzyme treatment and heat extraction by water. All extracts contained 11.8-18.0 mg/g loganin and showed antioxidation function assayed by measuring DPPH radical and hydrogen peroxide scavenging activity and reducing power. Among them, heat extraction was the most effective technique, showing a maximum amount of loganin (18.0 mg/g) and antioxidative activity at 100 mg/ml concentration. Each extract showed very low cytotoxicity up to at 500 mg/ml but 10-20% cytotoxicity at 1,000 mg/ml by in vitro MTT assay.

• Applied Biological Chemistry
• /
• v.46 no.1
• /
• pp.32-38
• /
• 2003

Seventy percent ethanolic extracts from commercially available 13 legumes were made to investigated their antioxidative activities by determining the reducing power, inhibitory effect on lipid peroxidation, scavenging activity against both superoxide radical and hydroxyl radical, together with inhibitory activity toward mitomycin C-induced oxidative damage of DNA. High level of reducing powers were detected in Yepat, Sokpiri, Yuweol-bean and Jeokdu. Inhibitory effects on lipid peroxidation were found ubiquitously in all extracts examined when employing the linoleic acid autoxidation system, whereas, only 3 legumes, Yepat, Namul-bean and Jeenuni-bean, were revealed marked inhibition in rabbit erythrocyte-ghost membrane lipid peroxidation system. Yepat, Namul-bean, Jeokdu and Jeenuni-bean showed great scavenging activities on superoxide radical, on the other hand, high level of hydroxyl radical scavenging activities were demonstrated in Sokpiri, Chungtae, Yepat and Jebi-bean. Ubiquitous inhibitory effects on mitomycin C-induced oxidative damage on DNA were found in all extracts tested, Among them, however, Yepat, Jeenuni-bean, Namul-bean, Nokdu and Jeokdu showed the higher level of inhibition. Taken together, we could assign Yepat, Jeokdu, Jeenuni-bean and Sokpiri, for the legume species highly functional on overall antioxidative activity.