• Herbal Formula Science
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• v.28 no.4
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• pp.327-337
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• 2020

Objective : Citri Unshius Pericarpium is the dried peel of mature fruit of Citrus unshiu Markovich and has been used to treat indigestion, vomiting, and removal of phlegm. This study investigated the hepatoprotective and antioxidant effect of CEE (Ethanol extract of Citri Unshius Pericarpium) in cadmium (CdCl₂)-treated HepG2 cells. Methods : Component analysis of Citri Unshius Pericarpium was analyzed by UPLC with C₁₈ column. Cell viability was determined by MTT assay. The enzyme activity of superoxide dismutase (SOD) and the level of reactive oxygen species (ROS) and reduced glutathione (GSH) were analyzed using commercially available kits. Results : Cadmium caused severe HepG2 cell death. Cadmium also increased ROS production, consistent with depletion of GSH and inhibition of the SOD enzyme. However, CEE treatment reduced cell death and relieved oxidative stress caused by cadmium toxicity. CEE lowered ROS levels and improved depletion of GSH levels. CEE also enhanced the enzymatic activity of SOD. In component analysis, hesperidin was the most abundant of the five marker compounds (Narigenin, Narigin, Narirutin, Hesperidin and Hesperidin), which assumes that hesperidin partially contributed to the antioxidant activity of CEE. Conclusion : These results suggested that CEE could be a potential substance to solve heavy metal-related health problems. In particular, inhibition of oxidative stress by CEE can be a way to treat liver damage caused by cadmium.

• Journal of Korean Society for Atmospheric Environment
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• v.16 no.4
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• pp.299-308
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• 2000

This study analyzed solid wastes generated from a school. The emission potential of hazardous pollutants generated from incineration of the school solid wastes (SSWs) was analyzed. Components of the SSWs were identified and the SSWs were classified into combustible and non-combustible wasts. The combustible wastes consisted of papers of 56.5^ plastics of 30.2% woods of 7.1% and fibers of 6.1% based on weight of the wastes. The moisture content and the ash content of the combustible wastes were 18~20% and 11~13% respectively. The combustible wastes of the SSWs were incinerated by using a small-scale incinerator. Fly and bottom ashes and volatile organic compounds (VOCs) were collected from the incineration. Also the metal leaching experiments on the fly and bottom ashes were performed, In analysis of metals leached from the ashes the total amounts of metals leached in the acid solution (pH=3) were much greater than those in the neutral solution (pH=5.8~6.2) For the same amounts of the fly and bottom ashes the total amounts of metals leached from the fly ashes were much greater than those from the bottom ashes. The VOCs produced from incineration of the SSWs consisted of aromatics of 42.1% aliphatic alkenes of 26.3% oxidized forms of 17.3% and aliphatic alkanes of 14.3% In addition the considerable amounts of hazardous air pollutants (e.g benzene chloro-benzene and chloro-alkanes) and compounds (e. g, aliphatic alkenes) with high potential of ozone or photochemical smog formation were identified from the incineration experiment of the SSWs.

• Environmental Analysis Health and Toxicology
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• v.21 no.2 s.53
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• pp.115-126
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• 2006

This study was conducted to find out survival rate, activity, growth and change of the organ structure of bivalves exposed to heavy metal. The results of the study confirmed that zinc (Zn) induces reduction of survival rate and activity, abnormality of organ structure of the equilateral venus, Gomphina veneriformis. Experimental groups were composed of one control condition and three Zn exposure conditions ($0.64mg\;Zn{\iota}^{1},\;1.07mg\;Zn{\iota}^{-1},\;1.79mg\;Zn{\iota}^{-1}$). As the concentration of zinc increased the accumulation of lipofucin increased in the digestive gland. Survival rate was the lowest in the lowest Zn exposure group at $0.64mg;Zn{\iota}^{-1}$. Growth was not significantly different between the control and exposure group. Activity. with the exception of the lowest Zn exposure group at $0.64mg\;Zn{\iota}^{-1}$, was similar between the control and exposure group. Histological analysis of organ system illustrated expansion of hemolymph sinus, loss of striated border of inner epidermis, increase in the number of mucous cell in the mantle. Also, histological degenerations as epithelial necrosis and hyperplasia of mucous cells are recognized in the gill and foot.

• Nuclear Engineering and Technology
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• v.52 no.2
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• pp.248-257
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• 2020

This study presents an initial design for a novel system consisting in a coupled nuclear reactor and a phase change material-based thermal energy storage (TES) component, which acts as a buffer and regulator of heat transfer between the primary and secondary loops. The goal of this concept is to enhance the capacity factor of nuclear power plants (NPPs) in the case of high integration of renewable energy sources into the electric grid. Hence, this system could support in elevating the economics of NPPs in current competitive markets, especially with subsidized solar and wind energy sources, and relatively low oil and gas prices. Furthermore, utilizing a prismatic-core advanced high temperature reactor (PAHTR) cooled by a molten salt with a high melting point, have the potential in increasing the system efficiency due to its high operating temperature, and providing the baseline requirements for coupling other process heat applications. The present research studies the neutronics and thermal hydraulics (TH) of the PAHTR as well as TH calculations for the TES which consists of 300 blocks with a total heat storage capacity of 150 MWd. SERPENT Monte Carlo and MCNP5 codes carried out the neutronics analysis of the PAHTR which is sized to have a 5-year refueling cycle and rated power of 300 MW_th. The PAHTR has 10 metric tons of heavy metal with 19.75 wt% enriched UO₂ TRISO fuel, a hot clean excess reactivity and shutdown margin of $33.70 and -$115.68; respectively, negative temperature feedback coefficients, and an axial flux peaking factor of 1.68. Star-CCM + code predicted the correct convective heat transfer coefficient variations for both the reactor and the storage. TH analysis results show that the flow in the primary loop (in the reactor and TES) remains in the developing mixed convection regime while it reaches a fully developed flow in the secondary loop.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.144-144
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• 2017

Micronutrients such as zinc (Zn), iron (Fe), manganese (Mn) have important roles for development and growth in plants but it also have roles in animals and humans. In previous studies, a Korean weedy rice, KH2J was selected to have tolerance to heavy metal, lead (Pb) compared with a cultivar, Milyang23. To identify QTLs for micronutrients concentration in grain, an F2 population (120 plants) were developed from a cross between KH2J and an indica rice cultivar, Milyang23. To measure the concentration of eight ions, Zn, Fe, Mn, Pb, calcium (Ca), copper (Cu), cadmium (Cd) and arsenic (As), grains were collected and digested with 65% nitric acid, and the ion contents were measured using inductively coupled plasma mass spectrometry. A total 27 putative quantitative trait loci (QTLs) were detected on 12 chromosomes by single point analysis and 22 putative QTLs were detected by composite interval mapping. The co-locations of QTL for Zn, Fe and Mn were observed on chromosome 5. The QTLs for Cd, Cu and Zn were co-localized on chromosome 10, and QTLs for Zn, As and Mn was on chromosome 12. The Zn concentration in F2 generation showed significant correlation with concentrations of As (r = -0.4), Cu (r = 0.5) and Fe (r = 0.2) (P < 0.01). Also, the Ca concentration was significantly related with Mn and Fe concentrations (P < 0.01). Fine mapping of these QTLs is underway to analyze their functional relationship.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.50 no.4
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• pp.352-358
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• 2017

The object of this study is to assess physicochemical and microbiological hazards involved during the processing of shellfish products such as oysters, clam, and mussels. Samples including raw materials, intermediates, and final products in the processing process were collected from seven simple-processed shellfish facilities. In the samples obtained from the facilities, viable cell count and coliform group were detected less than that of the Korean Government guidelines. In addition, the high-risk bacterial pathogens such as Escherichia coli O157:H7, Salmonella sp., and Listeria monocytogenes were not identified in raw materials and final products. However, the low-risk pathogens, Staphylococcus aureus and Vibrio parahaemolyticus, were detected in some final products. The level of heavy metal content in the final products tested in this study meets the recommendations by the Korean Government standard guidelines. No foreign materials in the final products were also observed. Considering these results, it was concluded that no significant food hazards exists in the processing process of simple-processed shellfish products. However, it is essential to improve the food safety control in the shellfish processing facilities since S. aureus, a personal sanitary indicative bacterium, was continuously detected over seven simple-processed shellfish facilities.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.25 no.10
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• pp.1514-1519
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• 2001

This paper is concerned with design, manufacturing and performance test of LIPCA ( Lightweight Piezo- composite Curved Actuator) using a top carbon fiber composite layer with near -zero CTE(coefficient of thermal expansion), a middle PZT ceramic wafer and a bottom glass/epoxy layer with high CTE. The main point of this design is to replace the heavy metal layers of THUNDER by thigh tweight fiber reinforced plastic layers without losing capabilities to generate high force and large displacement. It is possible to save weight up to about 30% if we replace the metallic backing material by the light fiber composite layer. We can also have design flexibility by selecting the fiber direction and the size of prepreg layers. In addition to the lightweight advantage and design flexibility, the proposed device can be manufactured without adhesive layers when we use epoxy resin prepreg system. Glass/epoxy prepregs, a ceramic wafer with electrode surfaces, and a graphite/epoxy prepreg were simply stacked and cured at an elevated temperature (177 $^{circ}C$ after following an autoclave bagging process. It was found that the manufactured composite laminate device had a sufficient curvature after detached from a flat mold. The analysis method of the cure curvature of LIPCA using the classical lamination theory is presented. The predicted curvatures are fairly in agreement with the experimental ones. In order to investigate the merits of LIPCA, a performance test of both LIPCA and THUNDE$^{TM}$ were conducted under the same boundary conditions. From the experimental actuation tests, it was observed that the developed actuator could generate larger actuation displacement than THUNDERT$^{TM}$.

• Journal of the East Asian Society of Dietary Life
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• v.23 no.2
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• pp.153-170
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• 2013

This study examined awareness and information acquisition behavior regarding food hygiene and safety of university students to improve safe dietary practices and to get basic information to develop educational materials for food safety. It was conducted among 276 university students of Qingdao University and Liaocheng University in Shandong province, China through a self-administered questionnaire. Data were analyzed by SPSS Windows V.19.0. To describe characteristics of the respondents, frequency distributions were used. In addition, t test, one-way analysis of variance and Duncan's multiple range tests were conducted. The results were as follows: The respondents were generally interested in food hygiene and safety. However, the level of awareness regarding the food hygiene and safety system in China was not high. Almost forty-five percent of the respondents did not think that foods produced and distributed in China were safe. For the reasons for their distrust, most of the students replied that they did not trust the safety 'because of distrust for hygiene of the food process', followed by 'because of distrust for food distribution' and 'because of excess or illegal use of food additives on food process'. The respondents answered for the concern level toward food hygiene and safety foodborne disease threatened food safety the most, followed by heavy metal contamination and endocrine disruptors. The respondents acquired most information from electronic media including TV and radio. Most of the students wanted to participate in food hygiene and safety education. Finally, when they found hazardous or foreign materials in food the most frequent reaction was 'paying attention in the next purchase', followed by 'notifying others', and 'letting it go this time but never buying that product in the future'.

• Journal of Environmental Health Sciences
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• v.36 no.3
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• pp.236-246
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• 2010

In preparative anti-corrosive coating experiments, polyaniline was obtained by reacting an oxidizing agent with the monomer aniline. Further, the primer coating was prepared using a variety of widely-used materials such as urethane resin. For the top coating, epoxy resin and acrylic urethane resin were used. Characteristics of the coatings were assessed according to KS and ASTM specifications, and the structure of the polyaniline was characterized using FT-IR and TGA. For analysis of anti-corrosive properties in salt-spray experiments, measurements of the oxidation state of iron and surface atomic analysis were conducted using XPS and SEM-EDX. Unlike general anti-corrosive coatings which exhibit anti-corrosive effects only as a primer coating, the anti-corrosive coatings using polyaniline as the anti-corrosive pigment showed a marked synergistic effect with the top coatings. In other words, the top coatings not only produce a fine view effect, but also increase, through interaction with the primer coatings, the resistance to diffusion of corrosive factors from the external environment. It was also found that, unlike the heavy metal oxide-forming layer of the passive barrier alone, the polyaniline anti-corrosive pigment oxidized iron at the interface with the iron substrate to form a passive barrier in the oxidic layer, and itself formed a potential barrier layer with anti-corrosive factors from the external environment. Although the passive layer was damaged, the damaged area did not become completely oxidized iron; on the contrary, it showed a tendency to reduction. This can be interpreted such that a passive layer is formed again on the damaged area, and that at the same time there is a tendency to self-healing.

• Korean Journal of Microbiology
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• v.33 no.2
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• pp.125-130
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• 1997

Microbial reduction of hexava1ent(VI) to trivalent(lII) chromium is regarded as one of the mechanisms that confers resistance to bacteria. In order to verify this hypothesis, we compared Cr(VI) resistance with Cr(VI) reduction among 20 phenotypically distinct environmental isolates from Cr-contaminated and uncontaminated soils. With glucose as an electron donor, Cr(VI) reduction by washed cell suspensions ranged from 0.014 to 0.305 mM Cr(VI) reduced $h^1$. Cr(VI) resistance of the isolates were measured by growth inhibitions on a liquid medium containing 2 mM Cr(VI) based on their decrease of $A_{630}1$ as compared to the controls without Cr(VI). The isolates had a broad range of resistance from no inhibition to 93.4% inhibition of their growth. Upon correlation analysis, there was no significant relationship between those two phenomena. At a population level, a comparison of % resistant viable counts among the Cr-contaminated and uncontaminated soils showed 19.1 % and 0.4% of their total viable counts, respectively. The difference of % resistance between two site,. strongly suggested that the Cr(VI) present in the soils influences natural selection for resistant phenotypes. However, it is unlikely that the Cr(VI) resistance is dependent solely on the reduction as judged by the correlation analysis.