• Proceedings of the Korean Society of Toxicology Conference
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• 2001.10a
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• pp.176-176
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• 2001

Endocrine disruptors have been implicated in carcinogenesis in animal studies, but carcinogenetic effects on human remain controversial. In order to examine the genotoxicity of two common endocrine disruptors, Bisphenol A and Diethylstilbestrol, cytogenetic endpoints including chromosome aberration(CA), sister chromatid exchange (SCE), micronuclei (MN) analyses and DNA damage by single cell gel electrophoresis (SCGE) were assayed.(omitted)

• Proceedings of the KSEEG Conference
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• 2007.04a
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• pp.161-163
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• 2007

• Journal of Bio-Environment Control
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• v.11 no.4
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• pp.168-174
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• 2002

A new circulating hydroponic system was invented for oriental melons grown in the greenhouse. For developing nutrient solution management techniques, we examined the changes of nutrient contents of circulating solution in three different types of new hydroponic systems. The yield and fruit quality of oriental melons in Hydroponics were better than those in soil culture. The substrate culture was appropriate fer hydroponics of oriental melons, and NFT was turned to be the opposite due to the physiological disorder during hot seasons. Yamazaki's melon solution with EC 2.0dS.m$^{[-10]}$ was the most appropriate for oriental melons. The new circulating hydroponic system seemed to be appropriate for oriental melons because of the stable EC, pH and the macro- and micro-element contents. NO$_3$-N, Ca and Mg contents in the circulating solution kept a good balance in all types of hydroponics. However, p content, compared to other types, decreased by the degree of 1 me.L$^{[-10]}$ in perlite medium. K content showed irregular status in perlite but showed the stable status in cocopeat. Generally, microelements, except Mo, showed stable absorption in the substrate culture. However, in NET, most of the elements showed irregular absorption except B and Mn. Microelement absorption, especially Cu, Zn and Mo, decreased during hot seasons.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.9
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• pp.418-424
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• 2017

Magnesium has a higher specific strength than other metals and is widely used industry wide due to its excellent vibration absorption ability and electromagnetic wave shielding property.For example, it is used for automobile parts such as car seat frames and cylinder heads, and is widely used in electronic products such as notebook cases and mobile phone cases. In addition, it is in the spotlight as a bone-implant material used to assist in the treatment of damaged bones when the bones are cracked or broken. Currently, Ti alloy, stainless steel and Co-Cr-Mo alloy are used as the implant material, and the Mg alloy remains in research stage. The current problem with bone implant implants is that the patients must undergo reoperation to remove the implants after joint surgery. Magnesium, however, can achieve sufficient strength compared to current materials. In addition, since it is self-decomposed after the recovery, reoperation is not necessary. In this paper, Mg alloys were designed by adding harmless Ca and Zn to the human body. In order to improve the strength and corrosion resistance, the final alloy was designed by adding a small amount of Sr as a grain refiner. The radioactive elements of Sr are harmful to the human body, but other naturally occurring Sr elements are harmless. Microstructure analysis of the alloys was performed by optical microscopy and scanning electron microscopy. The mechanical properties and corrosion characteristics were evaluated by tensile test, potentiodynamic test and immersion test.

• Economic and Environmental Geology
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• v.28 no.3
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• pp.251-257
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• 1995

Three PEA (Pulverised Fuel Ash) samples, which were fresh, 17 and some 40 years weathered, were collected from two major British power plants. Batch leaching tests with these samples using distilled water and simulated industrial leachate showed higher amounts of element liberation from fresh ash, including Ca, Na, K, S (as $SO^{2-}_4$, $Cr_{total}$, Cu, Li Ni, Mo and CI and this seems to indicate their surface association and easier dissolution when contact with water. On the contrary Mg, Al, Ba, Si, V, As and Se do not show such readily leachable concentrations and these elements might be more associated with glass fraction in PFA particle rather than surface. Although element concentrations in the weathered ash are much lower than those in the initial leachate from the fresh ash, elements are still detected as resonable concentrations, with rather constant levels and this seems to demonstrate the element release from unstable glass phase of PFA particle. Fe, Ca, $Cr_{total}$, Cu, Ni, Zn and Hg were removed from the synthetic leachate by PFA and this is also confirmed by gain in solid PFA. The order of element retention is Meaford weathered ash > Drax weathered ash > Drax fresh ash in decreasing order and this conforms with the degree of weathering. Namely, the more wethered, the more wethered, the more effective in metal retention from the synthetic leachate.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.46 no.2
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• pp.195-204
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• 2020

The purpose of this study was to investigate the effects of 14 Chung-bu medicinal materials described in the Dongui Bogam on inflammatory cytokine production in HaCaT human keratinocyte cells. In order to confirm this possibility, we screened inhibition activity of 17 cytokines using Bio-Plex Pro^TM Human Cytokine 17-plex assay in HaCaT cell lines. Of the 14 Chung-bu medicinal materials, Holotrichia (Ho) and Scorpio (Sc) exerted inhibitory effects on interleukin (IL)-5 production; Ho, Mantidis Ootheca (MO), and Hirudo (Hi) exerted inhibitory effects on IL-6 production; Ho, MO, Lumbricus (Lu), Hi, and Meretricis Concha (MC) showed significant inhibitory effects on IL-8 production; Gecko (Ge), Bombycis Faeces (BF), Cicadidae Periostracum (CP), and MC showed significant inhibitory effects on IL-13 production; and Testudinis Chinemis Plastrum et Carapax (TCPC), BF, and Lu exerted significant inhibitory effects on MIP-1β production. Results indicated that the Chung-bu medicinal materials might be a good candicate as potential anti-inflammatory agents for inhibition of skin inflammation. However, further investigations on these materials, including mechanistic studies, should be carried out to validated the effects in human skin equivalent models of dermatitis.

• Journal of the Korean Chemical Society
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• v.37 no.7
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• pp.635-641
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• 1993

Electrochemical cell, $Pt|air(PO_2=5.3{\times}10^{-3}atm)|Zr_{0.85}Ca_{0.15}O_{1.85}|air(PO_2= 0.21atm)|Pt$, has been designed to characterize the solid electrolyte and the temperature dependence of the electromotive force (EMF) has been measured in a temperature range of 600∼1000${\circ}$C. Solid electrolyte shows pure ionic conduction of the oxygen anion. The Fe-FexO, Co-CoO, Ni-NiO, and Cu2O-CuO electrodes have been prepared by mixing the 1 : 1 mole ratio of each metal and metal oxide and then by heating at 800${\circ}$C for 6 hours. Electrochemical cells, Pt│M(s), $MO(s)|Zr_{0.85}Ca_{0.15}O_{1.85}|air(PO_2=0.21atm)|Pt$, have been designed and the temperature dependence of the EMF has also been measured in the same temperature range. The changes of the thermodynamic state functions for the formation of the metal oxides are calculated from the electromotive forces and their temperature dependences. The material properties of the oxide systems are also discussed with the function changes.

• Korean Journal of Materials Research
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• v.24 no.12
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• pp.671-676
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• 2014

It is known that bones get damaged by accidents and aging. Since the discovery of Bioglass, various kinds of ceramics have been also found to bond to living bone; some of these ceramics are already being clinically used as bone-repairing materials. In the present study, antibacterial calcium silicate gel ($Ag-30CaO{\cdot}70SiO_2$ gel) was prepared by sol-gel method in order to control the microstructure, which is related to the dissolution rate and induction period of apatite formation in body environment. In addition, biological $Ag-30CaO{\cdot}70SiO_2$ is tested. This was done to impart antimicrobial activity to the $30CaO{\cdot}70SiO_2$. Ag ion was added during sol-gel synthesis to replace the $H_2O$ added during the making of the $30CaO{\cdot}70SiO_2$ gel, which has silver solutions of various concentration. After the sol-gel process, 1N-$HNO_3$ solution was used to wash the gel when synthesizing the gel, in order to maintain the porous structure and remove PEG, water soluble polymers. Then, the apatite forming ability of the sol-gel derived CaO-$SiO_2$ gels was investigated using simulated body fluid (SBF), which had almost the same ion concentration as that of human blood plasma. The gels were analyzed by FT-IR spectroscopy, SEM observation, XRD, and fluorescent microscopy. The apatite was successfully created even after washing the gel; apatite is present in an amorphous state, and was found to affect the concentration of the Ag ion in cells in MC3T3 live & dead assay results. From these results, it is suggested that a good material that can be used to repair defects of nature bone is $Ag-30CaO{\cdot}70SiO_2$ gel.

• Bulletin of the Korean Chemical Society
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• v.34 no.7
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• pp.2073-2080
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• 2013

In this study the effects of adding alkaline-earth (IIA) metal oxides to NiZr-loaded Zeolite Y catalysts were investigated on hydrogen rich production by ethanol steam reforming (ESR). Four kinds of alkaline-earth metal (Mg, Ca, Sr, or Ba) oxides of 3.0% by weight were loaded between the $Ni_6Zr_4O_{14}$ main catalytic species and the microporous Zeolite Y support. The characterizations of these catalysts were examined by XRD, TEM, $H_2$-TPR, $NH_3$-TPD, and XPS. Catalytic performances during ESR were found to depend on the basicity of the added alkaline-earth metal oxides and $H_2$ production and ethanol conversion were maximized to 82% and 98% respectively in 27($Ni_6Zr_4O_{14}$)3MgO/70Zeolite Y catalyst at $600^{\circ}C$. Many carbon deposits and carbon nano fibers were seen on the surface of $30Ni_6Zr_4O_{14}$/70Zeolite Y catalyst but lesser amounts were observed on alkaline-earth metal oxide-loaded 27($Ni_6Zr_4O_{14}$)3MO/70Zeolite Y catalysts in TEM photos after ESR. This study demonstrates that hydrogen yields from ESR are closely related to the acidities of catalysts and that alkaline-earth metal oxides reduce the acidities of 27($Ni_6Zr_4O_{14}$)3MO/70Zeolite Y catalysts and promote hydrogen evolution by preventing progression to hydrocarbons.

• Physical Therapy Rehabilitation Science
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• v.7 no.3
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• pp.109-113
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• 2018

Objective: The purpose of this study was to investigate the effects of fall experience and task complexity on gait performance in community-dwelling persons with chronic hemiparetic stroke. Design: Cross-sectional study. Methods: Thirty-three persons who had a history of stroke participated in this study. The participants included 18 persons (aged mean 54.0, mean score of 24.6 points on the Montreal Cognitive Assessment, MoCA) with fall experience (faller group) and 15 persons (aged mean 53.7, mean score of 24.7 points on the MoCA) without fall experience (non-faller group) in the previous six months. This study measured balance and gait performance at two different conditions (with/without 70% of water filled in a 200 cc cup). The participants were clinically assessed using the 10-meter walk test (10MWT), 6-minute walk test (6MWT), Berg Balance scale (BBS), Dynamic Gait Index (DGI), and Timed Up-and-Go (TUG) test. Results: After analyzation, persons in the faller group performed significantly better on the 10MWT, 6MWT, BBS, DGI, and the TUG test in the no-cup-carrying condition than those in the cup-carrying condition (p<0.05). The persons in the non-faller group also performed significantly better in all outcome measures with the no-cup-carrying condition than those in the cup-carrying condition (p<0.05). However, there was no interaction between fall experience and task complexity in the two groups. Conclusions: Our results showed that balance and gait performance depended on fall experience and task complexity but fall experience did not interact with task complexity. Clinicians should consider fall prevention and task complexity during therapeutic approaches in persons with hemiparetic stroke.