• The Korea Journal of Herbology
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• v.32 no.4
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• pp.39-46
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• 2017

Objectives : This study aims to provide basic data about Portulacae Herba (PH) extracts as natural antioxidants by considering diverse antioxidant activities of PH depending on solvents. Methods : The samples of PH were pulverized, and A hot water and a 70% EtOH were stir-extracted for two hours three times repeatedly in a water bath with a temperature of 95 degrees and at room temperature respectively to measure 7 kinds of antioxidant activities. Results : There were significant differences in total phenol content, because the total phenol content of the 70% EtOH extract was higher than the hot water extract's, and the total flavonoid content of the 70% EtOH extract($4.40{\mu}g/mg$) was nearly 3.8 times higher than the hot water extract's($1.16{\mu}g/mg$). DPPH and ABTS radical scavenging activities were 70% EtOH extract showed a little higher activity than the hot water extract, and at a concentration of $500{\mu}g/mg$, the highest scavenging activity was found in the 70% EtOH extract, not in the control group. Hydroxyl radical and $Fe^{2+}$ chelatingactivities were slightly higher in hot water extract than in 70% EtOH extract, and increased in a dose-dependent manner. Nitrite scavenging activities increased dose-dependently in the hot water and the 70% EtOH extract, regardless of the pH level, and scavenging activity of the 70% EtOH extract was higher at pH 1.2 than at pH 3.0. Conclusions : In conclusion, it is thought that PH hot water and 70% EtOH extract have antioxidant activities, and can be used as natural antioxidants in future.

• The Korea Journal of Herbology
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• v.34 no.1
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• pp.59-65
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• 2019

Objectives : This study reviewed the antioxidant activity of each part of Portulacae Herba (PH) in order to better analyze the possibility of PH being used as a natural material. Methods : The root, stem, and leaves of the PH were separated, dried at $50^{\circ}C$, put in a 70% ethanol and then extracted three times every six hours. Antioxidant activities was performed by measuring the total polyphenol and total flavonoid contents, DPPH, ABTS, nitrite, hydroxyl radical scavenging activity, and $Fe^{2+}$ chelating. Results : The total polyphenol and total flavonoid contents was highest in the root, then the leaves, and lastly the stem. DPPH and ABTS radical scavenging activities for the root extract indicated the highest activity followed by the leaf and stem extracts. It also showed similar activity to that of the ascorbic acid. Hydroxyl radical scavenging activity and $Fe^{2+}$ chelating activity resulted to be highest in the root extract and then the leaf and stem extracts. Nitrite scavenging activity decreased with higher pH levels, and activity was highest in the order of root extract, leaf extract, and stem extract. Also, in reaction to a solution with a pH 1.2 level, the root extract showed similar scavenging activity to that of BHT. Conclusions : Therefore, based on the above results, it was verified that the roots of PH have a high antioxidant level, and they can be considered to have potential to be applied to functional food, cosmetics, and medicine with antioxidant efficacy.

• BMB Reports
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• v.55 no.12
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• pp.633-638
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• 2022

Liver regeneration is a well-known systemic homeostatic phenomenon. The N⁶-methyladenosine (m⁶A) modification pathway has been associated with liver regeneration and hepatocellular carcinoma. m⁶A methyltransferases, such as methyltransferase 3 (METTL3) and methyltransferase 14 (METTL14), are involved in the hepatocyte-specific-regenerative pathway. To illustrate the role of METTL14, secreted from non-parenchymal liver cells, in the initiation phase of liver regeneration, we performed 70% partial hepatectomy (PH) in Mettl14 heterozygous (HET) and wild-type (WT) mice. Next, we analyzed the ratio of liver weight to body weight and the expression of mitogenic stimulators derived from non-parenchymal liver cells. Furthermore, we evaluated the expression of cell cycle-related genes and the hepatocyte proliferation rate via MKI67-immunostaining. During regeneration after PH, the weight ratio was lower in Mettl14 HET mice compared to WT mice. The expressions of hepatocyte growth factor (HGF) and tumor necrosis factor (TNF)-α, mitogens derived from non-parenchymal liver cells that stimulate the cell cycle, as well as the expressions of cyclin B1 and D1, which regulate the cell cycle, and the number of MKI67-positive cells, which indicate proliferative hepatocyte in the late G1-M phase, were significantly reduced in Mettl14 HET mice 72 h after PH. Our findings demonstrate that global Mettl14 mutation may interrupt the homeostasis of liver regeneration after an acute injury like PH by restraining certain mitogens, such as HGF and TNF-α, derived from sinusoidal endothelial cells, stellate cells, and Kupffer cells. These results provide new insights into the role of METTL14 in the clinical treatment strategies of liver disease.

• Analytical Science and Technology
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• v.21 no.5
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• pp.432-437
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• 2008

In this study, polysilanes were synthesized by electroreduction with different monomers such as $CH_3HSiCl_2$, $PhSiCl_3$, $CH_3SiCl_3$ and $(CH_3)_2SiCl_2$ by Mg electrodes under ultrasonic radiation. The effects of monomers and additives (p-dibromobenzene (DBB), naphthalene (NAPH) and anthracene (ANTH)) on the reaction rate were investigated. Polymerization of $PhSiCl_3$ among the four monomers showed the highest rate. p-dibromobenzene (DBB) was proved the most effective additive. Based on the observations, some possible reaction mechanisms of the polymerization were proposed.

• Korean Journal of Remote Sensing
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• v.14 no.4
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• pp.353-365
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• 1998

Light absorption coefficient per unit mass of particles, i.e., specific absorption coefficient, is important as one of the main parameters in developing algorithms for ocean color remote sensing. Specific absorption coefficient of chlorophyll ($a^*_{ph}$) and suspended sediment ($a^*_{ss}$) were analyzed with a spectrophotometer using the "wet filter technique" and "Kishino method" for the seawater collected in the Yellow and Mediterranean Sea. An improved data-recovery method for the filter technique was also developed using spectrum slopes. This method recovered the baselines of spectrum that were often altered in the original methods. High $a^*_{ph}({lambda})$ values in the oligotrophic Mediterranean Sea and low values in the Yellow Sea were observed, ranging 0.01 to 0.12 $m^2$/mg at the chlorophyll maximum absorption wavelength of 440 nm. The empirical relationship between $a^*_{ph}$(440nm) and chlorophyll concentrations () was found to fit a power function ($a^*_{ph}$=0.039 $^{-0.369}$), which was similar to Bricaud et al. (1995). Absorption specific coefficients for suspended sediment ($a^*_{ss}$) did not show any relationship with concentrations of suspended sediment. However, an average value of $a^*_{ss}$ ranging 0.005 - 0.08 $m^2$/g at 440nm, was comparable to the specific absorption coefficient of soil (loess) measured by Ahn (1990). The morepronounced variability of $a^*_{ss}$ than $a^*_{ph}$ was determined from the variable mixing ratio values between particulate organic matter and mineral. It can also be explained by a wide size-distribution range for SS which were determined by their specific gravity, bottom state, depth and agitation of water mass by wind in the sea surface.

• Journal of Engineering Education Research
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• v.16 no.3
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• pp.20-27
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• 2013

The purpose of this study is to compare the key research-related constructs, research insterest, research self-efficacy, research productivity, and research outcome expectation of the graduate students, who are participating in Global Ph.D Fellowship (GPF) and Brain Korea (BK) 21 projects. The overall results show that the mean scores of GPF students in research interest, research self-efficacy, research productivity, and research outcome expectation are higher than those of BK21. However, the higher mean scores of doctoral students in both GPF and BK21 projects imply that the longer you stay in graduate program, the better researcher you can be. Although GPF program selected higher potential students and they seem to work very hard with high expectation to be competent researchers, compatible outcome also could be possible by BK21 project.

• Journal of Environmental Science International
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• v.23 no.11
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• pp.1929-1941
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• 2014

Now a days, frequency of abnormally high temperatures like heat wave by global warming and climate change is increasing constantly and the number of patient with heat related illness are jumping rapidly. In this study, we chose the case day for the heat wave in Busan area(Busan and Yangsan), 2013 which it was the most hottest year during 21th century. And then, we analysed the weather condition using automatic synoptic observing system(ASOS) data. Also, four indices, heat index(HI), wet bulb globe temperature(WBGT), Man-ENvironment heat EXchange model(MENEX)'s results like Physiological subjective temperature(PST), Physiological strain(PhS), were calculated to evaluate the thermal comfort and stress quantitatively. However, thermal comfort was different as the each station and thermal comfort index during same time. Busan's thermal indices (HI: hot, WBGT: sweltering, PST: very hot, PhS: very hot) indicated relatively higher than Yansan's (HI: very hot, WBGT: sweltering, PST: very hot, PhS: sweltering). It shows that Busan near coast is relatively more comfortable than Yangsan located in inland.

• The Korean Journal of Ecology
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• v.15 no.2
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• pp.157-172
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• 1992

Studies were conducted to evaluate the differential al tolerance of suwon 205 and olmil wheats grown is nutrient solution and determine the impact of NH4+-N or Ca2+ nutrition of the response of the two wheat vareties to al. In various concentrations of al, olmil induced lower ph levels than suwon 205 in nutrient solutions and the reduction of root length and dry weight was greater in olmil than in suwon 205. The uptake of al was greater in root than in shoot of the two wheat varieties, but more increased in root of olimil. also the uptake of ca, mg, k and p was inhibited by al especialy decrease of ca and p uptake in roots of olmil was more pronounced than in those of suwon 205. In nutrient solutions that contained NH4+-N plus 9ppm al, the ability of both varienties to raise the ph was reduced as the level of NH4+-N in nutrient solutions was increased, and al-sensitive olimil induced lower ph than did al-tolerant suwon 205. al toxicity was intensified by increasing the concentration of NH4+-N in nurient and toxic effect was greater in olmil. al toxicity in the two wheat varieties was steadily increased as the ca level of nutrient solution was reduced, sepecialy this effect was stronger in al-sensitive olmil than in al-tolerant suwon 205.

• Journal of Biosystems Engineering
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• v.28 no.2
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• pp.117-126
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• 2003

This study was conducted to develop precision control system fur cold storage facility that could offer safe storage environment for green grocery. For that reason of neuro-fuzzy control system with learning ability algorithm and single chip neuro-fuzzy micro controller was developed for cold storage facility. Dynamic characteristics and hunting of neuro-fuzzy control system were far superior to on-off and fuzzy control system. Dynamic characteristics of temperature were faster than on-off control system by 1,555 seconds(123% faster) and fuzzy control system by 460 seconds(36.4% faster). When system was arrived at steady state. hunting was ${\pm}$0.5$^{\circ}C$ in on-off control system, ${\pm}$0.4$^{\circ}C$ in fuzzy control system, and ${\pm}$0.3$^{\circ}C$ in neuro-fuzzy control system. Hunting of humidity and wind velocity was also controlled precisely by 70 to 72.5% and 1m/s For storage experiment with onion, characteristics of neuro-fuzzy control system were tested. Dynamic characteristics of neuro-fuzzy control system made cold storage facility conducted precooling ability and minimized hunting.

• Advances in environmental research
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• v.9 no.1
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• pp.1-17
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• 2020

Pharmaceutically active compounds (PhACs) have become an environmental havoc in last few decades with reported cases of antibiotic resistant bacteria (ARB) and antibiotic resistant genes (ARGs), lethal effects over aquatic organisms, interference in natural decomposition of organic matter, reduced diversity of microbial communities in different environmental compartments, inhibition of growth of microbes resulting in reduced rate of nutrient cycling, hormonal imbalance in exposed organisms etc. Owing to their potential towards bioaccumulation and persistent nature, these compounds have longer residence time and activity in environment. The conventional technologies of wastewater treatment have got poor efficiency towards removal/degradation of PhACs and therefore, modern techniques with efficient, cost-effective and environment-friendly operation need to be explored. Advanced oxidation processes (AOPs) like Photocatalysis, Fenton oxidation, Ozonation etc. are some of the promising, viable and sustainable options for degradation of PhACs. Although energy/chemical or both are essentially required for AOPs, these methods target complete degradation/mineralization of persistent pollutants resulting in no residual toxicity. Considering the high efficiency towards degradation, non-toxic nature, universal viability and acceptability, AOPs have become a promising option for effective treatment of chemicals with persistent nature.