• Journal of the Korean Recycled Construction Resources Institute
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• v.4 no.3
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• pp.250-258
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• 2016

Until now, the construction material industry has been recognized as a typical environmental destruction industry. However, recently, in order to reduce $CO_2$ emission, the main cause of environmental problems, lots of studies have been done about recycling industrial by-products and construction wastes. Therefore, the purpose of this study is to confirm whether it is possible to use as an alternative material in cement production process as a part of the development of recycled cement using an inorganic construction waste. For this study, the inorganic construction wastes was collected and analyzed each chemical component by XRF(X-ray Fluorescene). Also, the inorganic construction wastes were combined based on the chemical component of the cement, to perform this analysis. As a result, when the inorganic construction wastes was properly combined, it is possible to consider the development of the recycled cement used the inorganic construction wastes.

• Restorative Dentistry and Endodontics
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• v.9 no.1
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• pp.25-35
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• 1983

The purpose of this study was the observe the toxic effects of root canal sealers in 108 white rats. Experimental animals were divided into control and experimental groups. Theree representative types of materials, such as AH26, Z.O.E. and F.R. were used in this study. Cavities were prepared on the left mandibular area of 108 white rats. Three different sealers were placed in as experiment and bone cavities were left without filling as control. The experimental animals were sacrificed by cervical dislocation at the intervals of 1, 3, 7, 14, 28 and 49 days after filling. Each specimen was fixed with 10% neutral formalin solution, decalcified with 5% nitric acid, embedded in paraffin and sectioned 5-7${\mu}$. in thickness. The paraffin sections stained with Hematoxylin - Eosin were observed through the ordinary light microscope. The results were as follows; 1. Slight toxic effect to surrounding tissue were found in every experimental specimen. 2. AH26 showed the highest inflammatory response, and F.R. showed the lowest inflammatory response which subsided and replaced by fibrosis at 4 weeks after filling. 3. The cavity filled materials, such as implanted root canal sealers, blood clots and necrotic tissue, showed a tendency to be absorbed gradually proportioned to the experimental periods. A small amount of cavity filled materials were observed in the bone cavities after 4 weeks. 4. Fibroblastic proliferation began to produce fibrous capsule around the bone cavity in 2 weeks after filling. Fibrosis was prominent at 4 weeks after filling. 5. Osteoblastic activity of surrounding bone was observed at first in 2 weeks after filling and prominent in 4 weeks after filling. Osteoblastic activity showed an increasing effect as the time prolonged. 6. Surrounding tissue of the bone cavities showed the features of tissue destruction and had very severe inflammatory response at an initial stage. Above-mentioned appeared to be recovered gradually proportioned to the experimental periods.

• Journal of Periodontal and Implant Science
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• v.27 no.4
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• pp.819-828
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• 1997

The purpose of this study was to evaluate the abrasion-resistance of root surface after NaF iontophoresis, Nd:YAG laser irradiation and combined treatment 50 anterior teeth with flat interproximal root surface that had been extracted due to periodontal destruction were selected. All teeth were treated by the same procedure as conventional periodontal root treatment, such as scaling and root planing, root conditioning with tetracycline HCI(lOOmg/ml, 5min). The pre-treatment weight of each tooth was measured by a dial scale(SHIMADEU Co, LIBROR EB-220HU, capacity 220.000 g, Japan). All teeth were divided into 5 groups as follows: Nd:YAG laser irradiation(group 1, 1 W, 100 mJ, 10Hz, fiberoptic-root surface distance=5mm, $10\;sec.{\times}6times$, EL.EN.EN060, Italy): NaF iontophoresis(group 2, $150{\mu}A$, 4 min}: Nd:YAG laser irradiation following NaF iontophoresis(group 3): NaF iontophoresis following Nd:YAG laser irradiation(group 4): No treatment(control group). Electric toothbrushing (Oral-B, Brown Co, Germany) was conducted during 1 hour($lO\;min.{\times}6\;times$). Subsequently post-treatment weight was remeasured by the same method as pre-treatment weight measurement. The difference of abrasion rate among all groups was statistically analyzed by ANOVA(SAS program). Following results were obtained: 1. The abrasion rate was significantly lower in Nd:YAG laser irradiation group than NaF iontophoresis group(p < 0.001). 2. The abrasion rate was significantly lower in combined groups of Nd:YAG laser irradiation and NaF iontophoresis than either Nd:YAG laser irradiation group or NaF iontophoresis group(p < 0.001). 3. There was no significant difference in abrasion rate according to application order in the combined groups(p > 0.05). 4. The abrasion rate was significantly lower in all experimental groups than control group(p < 0.001). The results suggest that combined treatment of Nd:YAG laser irradiation and NaF iontophoresis on exposed root surface after periodontal therapy can enhance the abrasion-resistance of root surface and may inhibit the root caries development.

• Journal of the Korean Society of Food Science and Nutrition
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• v.42 no.5
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• pp.697-704
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• 2013

The inhibitory effect of ethanol extracts from Curdrania tricuspidata leaves (CTL) on osteoarthritis was investigated in primary cultured rat cartilage cells and a monosodium-iodoacetate (MIA)-induced arthritis rat model. To identify the effects of CTL 80% ethanol extracts (CTL80) and CTL 10% ethanol extracts (CTL10) against $H_2O_2$ treatment in vitro, cell survival was measured by the MTT assay. Cell survival after $H_2O_2$ treatment increased with CTL80 and CTL10 close to normal up to $300{\mu}g/mL\;H_2O_2$. The mRNA expression of matrix metalloproteinases (MMPs) was determined MMP-7 and MMP-13 (known catabolic factors), were significantly inhibited by CTL 80 and CTL10; a $200{\mu}g/mL$ dose of CTL80 especially decreased MMP-13 expression. In vivo, osteoarthritis was induced by an intra-articular injection of MIA into the knee joints of rats, then CTL80 and CTL10 orally administered daily for 35 days. After the animals were sacrificed, histological evaluations of their knee joints revealed a reduction in polymorphonuclear cell infiltration and smooth synovial lining in the CTL80-500 group. Micro-CT analysis of hind paws from CTL80-500 and CTL10 showed a protection against osteophyte formation, soft tissue swelling, and bone resorption. In conclusion, CTL ethanol extracts are effective in ameliorating joint destruction and cartilage erosion in MIA-induced rats. CTL decreases and normalizes articular cartilage through preventing extracellular matrix degradation and chondrocyte injury, and could potentially serve as a therapeutic treatment for humans.

• Journal of Korean Society of Environmental Engineers
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• v.33 no.11
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• pp.783-789
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• 2011

Recently, auto-thermal thermophilic aerobic digestion (ATAD) has a great attention for destruction of wasted sludge biomass in wastewater treatment plant. Reduction of sludge concentration has been successfully achieved with pilot scale ATAD and ceramic filtration process in field condition. However, high concentration of COD, total nitrogen (TN) and total phosphorus (TP) was observed in filtrate, which should be treated before recirculation of filtrate to biological wastewater treatment plant. This study was focused on removal of nitrogen and phosphorus contained in the filtrate of ATAD, using struvite crystallization method. The effect of operational and environmental parameters (such as, N, P and Mg ion concentration and molar ratio, pH, reaction time, agitation strength, seed dosage, and reaction temperature) on the treatment of TN and TP with struvite crystallization were evaluated. Magnesium (as $MgCl_26H_2O$) and phosphorus (as $K_2HPO_4$) ions were, if necessary, added to increase nitrogen removal efficiency by the crystal formation. Average concentration of $NH_4^+-N$ and $PO_4^{3-}-P$ of the filtrate were 1716.5 mg/L and 325.5 mg/L, respectively. Relationship between removal efficiencies of nitrogen and phosphorus and molar ratios of $Mg^{2+}$ and $PO_4^{3-}-P$ to $NH_4^+-N$ was examined. Crystal formation and nitrogen removal efficiencies were significantly increased as increasing molar ratios of magnesium and phosphorus to nitrogen. As molar ratio of $Mg^{2+}:PO_4^{3-}-P:NH_4^+-N$ were maintained to 2 : 1 : 1 and 2 : 2 : 1, removal efficiencies of nitrogen and phosphorus were 71.6% and 99.9%, and 93.8% and 98.6%, respectively. However, the effect of reaction time, mixing intensity, seed dose and temperature on the struvite crystallization reaction was not significant, comparing to those of molar ratios. Settled sludge volume after struvite crystallization was observed to be reduced with increase of seed dose and to be increased at high temperature.

• Journal of Periodontal and Implant Science
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• v.33 no.4
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• pp.585-597
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• 2003

Porphyromonas gingivalis has been implicated as an important periodontophathic bacterium in the etiology and progression of periodontal diseases. It has been reported that P.gingivalis may mediate periodontal destruction not only directly through its virulence factors, but also indirectly by including complex host mediated inflammatory reponses. The purpose of this study was t o evaluate the effects of P.gingivalis on the bone formation and resorption by osteoblasts. For this purpose, after determining the concentration below which sonicated P.gingivalis extracts (SPEs) have no cytotoxicity on mouse calvarial primary osteoblastic (POB) cells, we investigated the effects of SPEs on the alkaline phosphatase (ALP) activity, matrix metalloproteinase (MMP) expression (MMP-2, -9, 13), and prostaglandin $E_2$ ($PGE_2$) release in POB cells by treatment with SPEs below that concentration. The results were as follows; 1. SPEs showed no cytotoxic effect on POB cells up to a concentration of 1 ${\mu}m$/ml. 2. The treatment with SPEs reduced ALP activity in a dose-dependent manner in POB cells, In addition, when we investigated the effect of SPEs (1 ${\mu}m$/ml) on ALP activity for different exposure periods, statistically significant inhibition of ALP activity was shown at 2 days of exposure, and further significant inhibition occurred by extending the periods of exposure. 3. The treatment with SPEs stimulated the gene expression of MMP-9 in POB cells. 4. The pre-treatment with SPEs increased the amount of $PGE_2$ released in POB cells. In summary, the present study shows that P.gingivalis could inhibit osteogenesis and stimulate bone resorption not only by reducing ALP activity but also by increasing MMP-9 mRNA expression in osteoblasts, possibly through an endogenous $PGE_2$ pathway. In addition, our results suggest that if P.gingivalis affects osteoblasts in early differentiation stage, such effects by P. gingivalis could be irreversible.

• Korean Security Journal
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• no.30
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• pp.7-32
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• 2012

Korea faces The 2014 Incheon Asian Games and 2018 Pyungchang Winter Olympics. It is imperative to hold a safe event for the economic benefits, enhancing Korea's image, social integration, national harmony and unity in order to be evaluated as a successful international event. Furthermore, since the international event tends to draw many spectators, the host country must be ready to accommodate a large number of injured people in the event of an accident or terror attack. As stadiums for international events are where a large number of spectators gather in, a large refuge is essential, when dangerous situations happen. In this study, evacuation simulation was conducted using three scenarios in order to predict escape behaviors of spectators during the large escape by destruction of safety systems of stadiums and assess escape safety. As the result, the following results and proposals were extracted. Firstly, it is considered that dangerous situations during the security of stadiums should be predicted in advance and concrete plans for a large refuge of spectators have to be established to minimize damage. Secondly, it was found that the reduction in evacuation exits has an important impact on evacuation in an emergency situation. It implies that securing escape exits are quite important. Thirdly, there were areas where spectators stayed, due to blocked escape exits, while they were dispersed and concentrated at once. It demonstrates that security plans considering properties of facilities are required to solve these problems.

• Korean Journal of Weed Science
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• v.6 no.2
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• pp.191-200
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• 1986

The study was conducted to screen paraquat-tolerant plant species among crops and weeds, using the response of plant like leaf disc discoloration, visual injury and dry weight in the presence of paraquat. Mechanism of paraquat-tolerance was investigated in strains of soybean through evaluating activities of superoxide dismutase and peroxidase and the multiplication of callus derived from soybean cotyledon. In crops, Kwanggyo has been selected as a paraquat-tolerant variety among soybean cultivars tested, and Hood as a susceptible one. In weeds, Polygonum aviculare, Chenopodium album and Pinellia ternata were evaluated as the paraquat resistant species, providing the possibility for the donor plant species for paraquat resistance. Activity of superoxide dismutase known to detoxify paraquat was markedly greater in Kwanggyo, a paraquat-tolerant cultivar than in Hood, a susceptible one. In addition, the similar response like superoxide dismutase was observed in peroxidese activity. The greater inhibition of callus multiplication was determined in Hood, a susceptible one than a tolerant one, Kwnggyo. Based on all the informations, it is strongly proposed that paraquat tolerance in soybean is due to destruction of $O_2^-$ by elevated concentration of superoxide dismutase in the tolerant cultivar.

• Korean Journal of Food Science and Technology
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• v.27 no.3
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• pp.375-379
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• 1995

Contents of ${\beta}-carotene$ and vitamin C in the vegetable(Angelica keiskei) juice were measured as a function of storing temperature$(-18^{\circ}C{\sim}35^{\circ}C)$ and period$(6{\sim}72\;hours)$. Content of ${\beta}-carotene$ was highest in the fresh juice and the degree of destruction of the ${\beta}-carotene$ was significantly increased as the storage temperature increased. Vitamin C in the juice stored at $4^{\circ}C$ decreased less than that of ${\beta}-carotene$. There was no significant difference in fatty acid compositions among in the fresh, freeze-dried juice and juice stored for 72 hours. Antioxidative activities of components extracted from the juice(fresh and stored for 24 hours) followed by incubating for 1 day were higher than that of ${\alpha}-tocopherol$ and then significantly decreased as incubation prolonged.

• Journal of the Korean Society of Physical Medicine
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• v.9 no.2
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• pp.151-159
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• 2014

PURPOSE: The purpose of this study was to evaluate whether light-emitting diodes (LED) irradiation could be effective in a noninvasive, therapeutic device for the treatment of osteoarthritis(OA). METHODS: Twenty-four male Sprague-Dawley rats were divided into four groups: Vehicle control (saline); monosodium iodoacetate-injection (MIA); LED irradiation after MIA injection (MIA-LED); indomethacin-treatment after MIA injection (MIA-IMT). OA was induced by intra-articular injection of 3 mg MIA through the patellar ligament of the right knee. Vehicle control rats were injected with an equivalent volume of saline. The LED was irradiated for 15 min/day for a week after 7 days of MIA treatment. To compare with the effect of LED irradiation, the indomethacin was administrated 20 mg/kg twice a week orally after 7 days of MIA treatment. Knee joints were removed and fixed overnight in 10% neutral buffered formalin and decalcified by EDTA for 2 week before being embedded in paraffin. The assessment of OA induction were monitored by knee movement and radiographic finding. Histologic analysis were performed following staining with hematoxylin and eosin, safranin O-fast green, or toluidine blue, picrosirius red, and histologic changes were scored according to a modified Mankin system. Apoptotic cell in tissue sections was detected using TUNEL method. RESULTS: Radiographic examination could not show the differences between the MIA-treated and the MIA-LED-treated rats. In the histologic analysis, however, LED irradiation prevented cartilage damage and subchondral bone destruction, and significantly reduced mononuclear inflammatory cell infiltration and pannus formation. LED irradiation also reduced apoptosis of cartilage cells, but it prevented apoptosis of infiltrated inflammatory cells in synovium. In addition, LED irradiation showed an increase of collagen production in the meniscus. CONCLUSION: These results suggest that the 840 nm LED irradiation would be a suitable non-thermal phototherapy for the treatment of OA, as a cartilage protection and anti-inflammatory modality.