• Journal of the Mineralogical Society of Korea
• /
• v.21 no.4
• /
• pp.425-434
• /
• 2008

Arsenic contamination in soil and groundwater has recently been one of the most serious environmental concerns. This arsenic contamination can be originated from natural or anthropogenic sources. It has been well known that arsenic behavior in geo-environmental is controlled by various oxides or hydroxides, such as those of iron, manganese, and aluminum, and clay minerals. Among those, particularly, iron (oxy)hydroxides are the most effective scavengers for arsenic. For this reason, this study characterized arsenic adsorption of magnetite which is a kind of iron oxide in nature. The physicochemcial features of the magnetite were investigated to evaluate adsorption of arsenite [As(III)] and arsenate [As(V)] onto magnetite. In addition to experiments on adsorption equilibria, kinetic experiments were also conducted. The point of zero charge (PZC) and specific surface area of the laboratory-synthesized magnetite used as an arsenic adsorbent were measured 6.56 and $16.6\;g/m^2$, which values seem to be relatively smaller than those of the other iron (oxy)hydroxides. From the results of equilibria experiments, arsenite was much more adsorbed onto magnetite than arsenate, indicating the affinity of arsenite on magnetite is larger than arsenate. Arsenite and arsenate showed adsorption maxima at pHs 7 and 2, respectively. In particular, adsorption of arsenate decreased with increase in pH as a result of electrical repulsion caused by anionic arsenate and negatively-charged surface of magnetite. These results indicate that the surface charge of magnetite and the chemical speciation of arsenic should be considered as the most crucial factors in controlling arsenic. The results of kinetic experiments show that arsenate was adsorbed more quickly than arsenite and adsorption of arsenic was investigated to be mostly completed within the duration of 4 hours, regardless of chemical speciation of arsenic. When the results of kinetic experiments were fitted to a variety of kinetic models proposed so far, power function and elovich model were evaluated to be the most suitable ones which can simulate adsorption kinetics of two kinds of arsenic species onto magnetite.

• Journal of Korean Society for Atmospheric Environment
• /
• v.34 no.4
• /
• pp.567-587
• /
• 2018

A severe haze event occurred in October 2015 in Gwangju, Korea. In this study, the driving chemical species and the formation mechanisms of $PM_{2.5}$ pollution were investigated to better understand the haze event. Hourly concentrations of $PM_{2.5}$, organic and elemental carbon, water-soluble ions, and elemental constituents were measured at the air quality intensive monitoring station in Gwangju. The haze event occurred was attributed to a significant contribution (72.3%) of secondary inorganic species concentration to the $PM_{2.5}$, along with the contribution of organic aerosols that were strongly attributed to traffic emissions over the study site. MODIS images, weather charts, and air mass backward trajectories supported the significant impact of long-range transportation (LTP) of aerosol particles from northeastern China on haze formation over Gwangju in October 2015. The driving factor for the haze formation was stagnant atmospheric flows around the Korean peninsula, and high relative humidity (RH) promoted the haze formation at the site. Under the high RH conditions, $SO{_4}^{2-}$ and $NO_3{^-}$ were mainly produced through the heterogenous aqueous-phase reactions of $SO_2$ and $NO_2$, respectively. Moreover, hourly $O_3$ concentration during the study period was highly elevated, with hourly peaks ranging from 79 to 95ppb, suggesting that photochemical reaction was a possible formation process of secondary aerosols. Over the $PM_{2.5}$ pollution, behavior and formation of secondary ionic species varied with the difference in the impact of LTP. Prior to October 19 when the influence of LTP was low, increasing rate in $NO_3{^-}$ was greater than that in $NO_2$, but both $SO_2$ and $SO{_4}^{2-}$ had similar increasing rates. While, after October 20 when the impact of haze by LTP was significant, $SO{_4}^{2-}$ and $NO_3{^-}$ concentrations increased significantly more than their gaseous precursors, but with greater increasing rate of $NO_3{^-}$. These results suggest the enhanced secondary transformation of $SO_2$ and $NO_2$ during the haze event. Overall, the result from the study suggests that control of anthropogenic combustion sources including vehicle emissions is needed to reduce the high levels of nitrogen oxide and $NO_3{^-}$ and the high $PM_{2.5}$ pollution occurred over fall season in Gwangju.

• Journal of Korean Society of Environmental Engineers
• /
• v.34 no.7
• /
• pp.445-453
• /
• 2012

An investigation for removal of 1-indanone (1-ID), which were commonly produced from the biological and/or chemical treatment and natural weathering of the PAHs-contaminated soils, via oxidative transformation mediated by birnessite in the presence of various phenolic mediators is described. This study also examines the potential effect of the natural occurring substance humic acid (HA) on the oxidative transformation. The experiment was carried out in aqueous phase as a batch test (10 mg/L 1-ID, 0.3 mM phenolic mediators, $1.0g/L\;{\delta}-MnO_2$, at pH 5). All of the 11 tested phenoilic mediators belong to the group of natural occurring phenols and are widely used as model constituents of humic substances. From the results of HPLC analysis, it is demonstrated that 1-ID was not reactive to birnessite itself, but it can be effectively removed in birnessite-mediated cross coupling reactions in the presence of the phenolic mediators. The percent removals of 1-ID after 2 day incubation were ranged from 9.2 to 71.2% depending on the phenolic mediators applied. The initial rate constant ($K_{int}$, $hr^{-1}$) values for the 1-ID removals obtained from the pseudo-first-order kinetic plots also widely ranged from 0.18 to 15.0. Results of the correlative analysis between the removal efficiencies and structural characteristics of phenolic mediators indicate that the transformation of the 1-ID was considerably enhanced by the addition of electron-donating substituents (e.g., -OH, $-OCH_3$) at the benzne ring, and much less enhanced by the addition of electron-withdrawing substituents (e.g., -COOH, -CHO). The presence of HA showed that removal efficiencies of 1-ID in the birnessite-phenolic mediator systems decreased with increasing HA concentrations. However at low concentration of HA (< 2 mg/L), it caused some enhancement in the removals of 1-ID as compared to the control.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.34 no.6
• /
• pp.600-604
• /
• 2001

For the effective utilization of cuttle bone as a calcium powder, we examined calcination condition ($700^{\circ}C: 0\sim10\;hrs,\;800^{\circ}C:\;0\sim3\;hrs,\;900^{\circ}C:\;0\sim1\;hr\;and\;1,000^{\circ}C:\;0\sim30\;mins$) for recovery of calcium from raw cuttle bone powder (RCB) and characteristics of calcined cuttle bone powder (CCB) treated by optimal condition. During calcination of RCB, the yields was decreased, while total and soluble calcium contents and white index were increased up to constant calcination time ($8\;hrs\;at\;700^{\circ}C,\;2\;hrs\;at\;800^{\circ}C,\;45\;min\;at\;900^{\circ}C\;and\;20\;min\;at\;1,000^{\circ}C$). But, these after that almost unchanged. From these results, the optimal calcination conditions for recovery of calcium from RCB were revealed $8\;hrs\;at\;700^{\circ}C,\;2\;hrs\;at\;800^{\circ}C,\;45\;min\;at\;900^{\circ}C\;and\;20\;min\;at\;1,000^{\circ}C$. In the case of CCB treated for 2 hrs at $800^{\circ}C$, total calcium was about $70\%$, the major component was calcium oxide, and the structure consisted of porosity. The calcium solubility of CCB increased by 22 times compared to RCB. But, the pH of RCB was about 12.9. Therefore, for the effective utilization of RCB as a calcium powder, it requires a suitable modification operation for adjustment of pH ($pH\;2.0\~9.0$).

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.35 no.2
• /
• pp.166-172
• /
• 2002

The top shell, Omphalius pfeifferi capenteri meat vacuum-packed in can (diameter$\times$height, 74.1mm$\times$50.7mm) were heated at 115$^{\circ}C$ up to $F_0$ values of 5 min, 10 min, 15 min and 20 min, and the changes in food components were studied. After 14 days storage at 37$^{\circ}C$ and 55$^{\circ}C$, no growth of microorganism and panelling were recognized from the canned meats which were sterlized at 115$^{\circ}C$ with $F_0$ value of S min and over. In the case of proximate composition of the canned meats, the moisture content decreased with the increase of $F_0$ value, while crude protein increased. The increase of volatile basic nitrogen content, pH and degree of browning and the decrease of mineral, total amino acid, free amino acid, trimethylamine oxide, total creatinine contents and yields were observed during thermal processing, In sensory evaluation on color, texture and taste in the canned meats, no significant difference was observed among a boiled sample and the canned meats heated at re value of 10 min and below. But, in the canned meats heated at $F_0$ value of over 15 min, its sensory scores decreased with the increase of $F_0$ value. From these results, the reasonable $F_0$ value for preparation of the heat-treated top shell meats was in the range of 5$\~$10 min.

• Restorative Dentistry and Endodontics
• /
• v.31 no.1
• /
• pp.36-49
• /
• 2006

The purpose of this study was to compare the cytotoxicity by MTT test and genotoxicity by Ames test of new calcium phosphate-based root canal sealers (CAPSEAL I, CAPSEAL II) with commercially available resin-based sealers (AH 26, AH Plus) , zinc oxide eugenol-based sealers (Tubliseal EWT, Pulp Canal Sealer EWT), calcium hydroxide-based sealer (Sealapex), and tricalcium phosphate based sealers (Sankin Apatite Root Canal Sealer I, II, III). According to this study, the results were as follows : 1. The extracts of freshly mixed group showed higher toxicity than those of 24 h set group in MTT assay (p<0.001). 2. CAPSEAL I and CAPSEAL II were less cytotoxic than AH 26, AH Plus, Tubliseal EWT, Pulp Canal Sealer EWT Sealapex and SARCS II in freshly mixed group (p<0.01). 3. AH 26 in freshly mixed group showed mutagenicity to TA98 and TA100 with and without S9 mix and AH Plus extracts also were mutagenic to TA100 with and without S9 mix. 4. Tubliseal EWT, Pulp Canal Sealer EWT and Sealapex in freshly mixed group were mutagenic to TA100 with S9 mix. 5. Among those of 24 h set groups the extracts of SARCS II were mutagenic to TA98 with and without S9 mix and AH 26 showed mutagenic effects to TA98 with S9 mix. 6. No mutagenic effect of CAPSEAL I and CAPSEAL II was detected. 7. There is no statistically significant difference between CAPSEAL I and CAPSEAL II at MTT assay and Ames test in both freshly mixed group and 24 h set group.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.34 no.8
• /
• pp.1157-1163
• /
• 2005

The current study examined the effects of radish loaves powder on hepatic antioxidative system in rats fed high-cholesterol diet. Sprague-Dawley male rats weighing 100$\pm$10 g were randomly assigned to normal group (N group), normal diet with 5$\%$ radish leaves powder supplemented group (NR group) and high-cholesterol groups, which were sub-divided into radish leaves powder free diet group (HC group) and 2.5$\%$ (HRL group), 5$\%$ (HRM group), 10$\%$ (HRH group) radish leaves powder supplemented groups. Hepatic super oxide dimutase activity was no significant differences. Hepatic glutathione peroxidase activity was sig-nificantly increased in 5$\%$, 10$\%$ radish leaves powder supplemented groups. Hepatic hydrogen peroxide contents in cytosol were no significantly differences Hepatic hydrogen peroxide contents in mitochondria were sig-nificantly reduced in radish leaves powder supplemented groups. Hepatic superoxide radical contents in mi-crosome were significantly reduced in radish leaves powder supplemented groups. Hepatic superoxide radical contents in mitochondria were significantly reduced in 5$\%$, 10$\%$ radish leaves powder supplemented groups. Hepatic TBARS values were significantly reduced in 5$\%$, 10$\%$ radish leaves powder supplemented groups. Hepatic lipofuscin contents were no significant difference in high-cholesterol groups. Hepatic carbonyl values were significantly reduced in 5$\%$, 10$\%$ radish leaves powder supplemented groups among high-cholesterol groups. The results indicate that radish leaves may reduce oxidative damage by activating antioxidative de-fense system of liver in rats fed high-cholesterol diets.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.36 no.7
• /
• pp.866-873
• /
• 2007

To analyze and differentiate volatile compounds of 13 extra virgin olive oils from market, solid-phase micro extraction (SPME) GC-MS and electronic nose (EN) equipped with metal oxide sensors were applied. The volatiles identified in extra virgin olive oils include hexanal, 4-hexen-1-ol, (Z)-3-hexen-1-ol, acetic acid, and 2,4-dimethyl-heptane, etc. Response from EN was analysed by the principal component analysis. Proportion of the first Principal component was 99.70%, suggesting that each aroma pattern of the 13 extra virgin olive oils could be discriminated by EN. Fatty acid compositions were oleic (61.1${\sim}$77.9 mole%), palmitic (11.7${\sim}$16.5 mole%), linoleic (4.7${\sim}$9.7 mole%), stearic (2.5${\sim}$2.9 mole%), Palmitoleic (0.8${\sim}$2.4 mole%), and linolenic acid (0.7${\sim}$1.2 mole%). In color study, extra virgin olive oil showed $L^{\ast}$ value of 81.7${\sim}$92.9, $a^{\ast}$ value of -28.3${\sim}$13.5 and $b^{\ast}$ value of 52.2${\sim}$139.0. Total phenol and ${\alpha}-tocopherol$ contents were 6.2${\sim}$24.9 mg/100 g and 5.5${\sim}$12.8 mg/100 g, respectively. In Rancimat test, the induction period of 13 extra virgin olive oils showed 31.76${\sim}$54.04 hr while their POV ranged from 13.5 to 22.9 meq/kg oil.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.40 no.5
• /
• pp.625-634
• /
• 2011

Green tea seed coat (GTSC) was extracted with 100% ethanol for 4 hr and then fractionated with petroleum ether (PE), ethyl acetate (EtOAC) and butanol (BuOH). The EtOAC fraction showed the highest level in total phenol contents and the lowest level in nitric oxide (NO) production in LPS-stimulated RAW264.7 macrophage cell. Thus, this study was carried out to investigate the anti-inflammatory and its mechanisms of GTSC EtOAC fraction in LPS-stimulated RAW264.7 macrophage cell. GTSC EtOAC fraction contained EGC ($1146.48{\pm}11.01\;{\mu}g/g$), tannic acid ($966.99{\pm}32.24\;{\mu}g/g$), EC ($70.88{\pm}4.39\;{\mu}g/g$), gallic acid ($947.61{\pm}1.03\;{\mu}g/g$), caffeic acid ($37.69{\pm}1.46\;{\mu}g/g$), ECG ($35.46{\pm}3.19\;{\mu}g/g$), and EGCG ($15.53{\pm}0.09\;{\mu}g/g$) when analyzed by HPLC. NO production was significantly (p<0.05) suppressed in a dose-dependent manner with an $IC_{50}$ of $80.11\;{\mu}g$/mL. Also prostaglandin $E_2$ level was also inhibited in a dose-dependent manner. Moreover, iNOS protein expression was suppressed in dose-dependent manner but COX-2 gene expression was not affected. Total antioxidant capacity and glutathione (GSH) levels were enhanced more than the LPS-control. Expressions of antioxidative enzymes including catalase, GSH-reductase and Mn-SOD were elevated compared to LPS-control. Nuclear p65 level was decreased in the GTSC EtOAC fraction in a dose-dependent manner. These results indicate that GTSC EtOAC fraction inhibit oxidative stress and inflammatory responses through elevated GSH levels, antioxidative enzymes expressions and suppression of iNOS expression via NF-${\kappa}B$ down-regulation.

• Journal of the Society of Cosmetic Scientists of Korea
• /
• v.37 no.3
• /
• pp.199-210
• /
• 2011

This study was conducted to develop functional sources of herbal cosmetics for treatment of skin aging and inflammatory disorders using volatile flavor extracts of four different herbal medicinal prescriptions including Cnidium officinale Makino (COM), Angelica gigas Nakai (AGN), Mentha arvense L. (MAL), Artemisiae argyi Folium (AAF), Paeonia lactiflora Pall (PLP), Rehmanniae Radix Preparata (RRP), Scutellaria baicalensis Georgi (SBG), Panax ginseng C.A. Meyer (PGM), Glycyrrhiza uralensis Fisch (GUF). The volatile flavor extracts of four different herbal medicinal prescriptions (HH-1: COM, AGN, PLP, RRP, HH-2: COM, AGN, PLP, RRP, SBG, PGM, GUF, HH-3: COM, AGN, MAL, AAF, HH-4: COM, AGN, MAL, AAF, SBG, PGM, GUF) were extracted using SDE and their antioxidant and anti-inflammatory effects were measured by using DPPH radical and SLO, respectively. As a result, HH-2 showed moderate DPPH radical scavenging activity (68.24 %) and the strongest SLO inhibitory activity (83.96 %) at 100 ${\mu}g$/mL. Moreover, HH-2 of four different prescriptions significantly inhibited NO production on LPS-stimulated RAW 264.7 cells in a dose-dependent manner without considerable cell cytotoxicity at range of 2.0 ~ 50 ${\mu}g$/mL. Additionally, HH-2 also effectively suppressed the production of $PGE_2$ and IL-6, which are responsible for promoting the inflammatory process. Major volatile components of HH-2 were identified as eugenol, paeonol, butyl phthalide, ${\beta}$-eudesmol and butylidene dihydrophthalide by GC-MS analysis. Thus, these results suggest that HH-2 may be useful as a potential source of anti-inflammatory agents in herbal medicinal cosmetics.