• Journal of Forest and Environmental Science
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• v.33 no.2
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• pp.113-121
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• 2017

In flight particulate matter particularly emissions generated by incomplete combustion processes has become a subject of global concern due to the health problems and environmental impacts associated with them. This has compelled most countries to set standards for coarse and fine particles due to their conspicuous impacts on environment and public health. This contribution therefore explores forest fire emissions and how its particulates affects air quality, damage to vegetation, water bodies and biological functions as architects for lung diseases and other degenerative illnesses such as oxidative stress and aging. Soot was collected from simulated forest fire using a clean glass surface and carefully transferred into amber vials for analysis. Volatile components of soot were collected over 10 mL dichloromethane and analyzed using a QTOF Premier-Water Corp Liquid Chromatography hyphenated to a mass selective detector (MSD), and Gas Chromatograph coupled to a mass spectrometer (GC-MS). To characterize the size and surface morphology of soot, a scanning electron microscope (SEM) was used. The characterization of molecular volatiles from simulated forest fire emissions revealed long chain compounds including octadec-9-enoic acid, octadec-6-enoic acid, cyclotetracosane, cyclotetradecane, and a few aromatic hydrocarbons (benzene and naphthalene). Special classes of organics (dibenzo-p-dioxin and 2H-benzopyran) were also detected as minor products. Dibenzo-p-dioxin for instance in chlorinated form is one of the deadliest environmental organic toxins. The average particulate size of emissions using SEM was found to be $11.51{\pm}4.91{\mu}m$. This study has shown that most of the emissions from simulated forest fire fall within $PM_{10}$ particulate size. The molecular by-products of forest fire and particulate emissions may be toxic to both human and natural ecosystems, and are possible precursors for various respiratory ailments and cancers. The burning of a forest by natural disasters or man-made fires results in the destruction of natural habitats and serious air pollution.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.27 no.3
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• pp.432-439
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• 2003

Inconel 690 for nuclear steam generator tube has more Chromium than the conventionally used Inconel 600 in order to increase the corrosion resistance. To evaluate the tribological characteristics of Inconel 690 under fretting condition the fretting tests were carried out in air and elevated temperature water. Fretting tests of the cross-cylinder type were done under various vibrating amplitudes and applied normal loads in order to measure the friction forces and wear volumes. From the results of fretting wear tests. the wear of Inconel 690 can be predictable using the work rate model. The amounts of friction forces were proportional to relative movement between two fretting surfaces. The friction coefficients were decreased as increasing the normal loads and deceasing the vibrating amplitudes. Depending on fretting environment, distinctively different wear mechanisms and often drastically different wear rates can occur It was found that the fretting wearfactors in air and water at 2$0^{\circ}C$, 5$0^{\circ}C$, and 8$0^{\circ}C$ were 7.38 $\times$ $10^{-13}$$Pa^{-1}$, 2.12 $\times$$10^{-13}$$Pa^{-1}$, 3.34$\times$$10^{-13}$$Pa^{-1}$and 5.21$\times$$10^{-13}$$Pa^{-1}$, respectively flexibility to model response data with multiple local extreme. In this study, metamodeling techniques are adopted to carry out the shape optimization of a funnel of Cathode Ray Tube, which finds the shape minimizing the local maximum principal stress. Optimum designs using two metamodels are compared and proper metamodel is recommended based on this research.

• Fisheries and Aquatic Sciences
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• v.18 no.1
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• pp.45-50
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• 2015

A 10-day trial was conducted to evaluate the salinity tolerance and hematological responses of juvenile ship sturgeon Acipenser nudiventris under different salinity levels. A total of 240 fish averaging $6.2{\pm}0.13g$ (mean${\pm}$SD) were randomly distributed into 12 tanks in groups of 20, and each tank was then randomly assigned to one of three replicates of four different salinities at 0, 4, 8 and 12‰. At the end of 10 days of experimental period, plasma protein value of fish exposed to 0‰ and 4‰ salinities was significantly higher than those of fish exposed to 8‰ and 12‰ salinities (P < 0.05). Significantly higher values for plasma cortisol and glucose were obtained in fish exposed to 12‰ salinity compared to the fish exposed to 0‰ and 4‰ salinities (P < 0.05). Plasma potassium and sodium values increased significantly by increment of salinity levels (P < 0.05). Therefore, these results indicated that in natural environments, juvenile ship sturgeon, A. nudiventris in migratory populations could be able to migrate and adjust successfully into brackish water with a salinity of up to 8‰ without any short-term hematological stress responses.

• Molecular & Cellular Toxicology
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• v.2 no.2
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• pp.75-80
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• 2006

Biomarkers identify various stages and interactions on the pathway from exposure to disease. The three categories of biomarkers are those measuring susceptibility, exposure and effect. Susceptibility biomarkers are identifiable genetic variations affecting absorption, metabolism or response to environmental agents. Biomarkers of exposure indicate the amount of a foreign compound that is absorbed into the body. Biological measurements performed on human tissues are vastly expanding the capabilities of classical epidemiology, which has relied primarily on estimates of human exposure derived form chemical levels in the air, water, and other exposure routes. Biomarkers of exposure indicate the amount of a foreign compound that is absorbed into the body. Biological measurements performed on human tissues are vastly expanding the capabilities of classical epidemiology, which has relied primarily on estimates of human exposure derived form chemical levels in the air, water, and other exposure routes. The biomarker response is typical of chemical pollution by specific classes of compound, such as (i) heavy metals (mercury, cadmium, lead, zinc), responsible for the induction of metallothionein synthesis, and (ii) organochlorinated pollutants (PCBs, dioxins, DDT congeners) and polycyclic aromatic hydrocarbons (PAHs), which induce the mixed function oxygenase (MFO) involved in their bio transformations and elimination. Currently genomic researches are developed in human cDNA clone subarrays oriented toward the expression of genes involved in responses to xenobiotic metabolizing enzymes, cell cycle components, oncogenes, tumor suppressor genes, DNA repair genes, estrogen-responsive genes, oxidative stress genes, and genes known to be involved in apoptotic cell death. Several research laboratories in Korea for kicking off these Environmental Genomics were summarized.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.24 no.3 s.174
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• pp.603-612
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• 2000

Corrosion characteristics on the 12Cr alloy steel of turbine blade was electro-chemically investigated in 3.5wt% NaCI and 12.7wt% Na2S04 solution, respectively. Electro-chemical polarization test, Huey test and Oxalic acid etching test were previously conducted to estimate corrosion susceptibility of the material. And, using the horizontal corrosion fatigue tester, corrosion fatigue characteristics of 12Cr alloy steel in distilled water, 3.5wt% NaCI solution, and 12.7wt%(1M) Na2S04 solution were also fracture-mechanically estimated and compared their results. Parameter considered was room temperature, 60'C and 90'C. Corrosion fatigue crack length was measured by DC potential difference method.Obtained results are as follows,1) 12Cr alloy steel showed high corrosion rate in 3.5wt% NaCI solution and Na2S04 solution at high tempratue.2) Intergranular corrosion sensitivity of 12 Cr alloy was smaller than austenitic stainless steel.3) Corrosion fatigue crack growth rate in 3.5wt% NaCI and 12.7wt%(IM) Na2S04 solution is entirely higher than in the distilled water, and also increased with the temperature increase.

• Journal of Korean Tunnelling and Underground Space Association
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• v.13 no.1
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• pp.9-18
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• 2011

The spalling phenomenon occurs in high-strength concrete when several factors such as sharp temperature increase, high water content, low water/cement ratio and local stress concentration in material combine in the concrete material. On the basis of the factors, the preventing methods from the spalling are known as reduction of temperature increase, preventing of concrete fragmentation and fast drying of internal moisture. In this study, the reduction of temperature increase was proposed as the most effective spalling-preventing method among the spalling-preventing methods. Engineered cementitious composite for fireproof and repair materials was developed in order to protect the new and existing RC structures form exterior deterioration factors such as fire, cloride ion, etc. This study was carried out to estimate the fire-resisting performance of high strength concrete slab or tunnel lining by repaired engineered cementitious composite (ECC) or fiber reinforcement cemetitious composite (FRCC) under fire temperature curve. and them we will descrike the result of HIDA tunnel in Japan.

• Tunnel and Underground Space
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• v.8 no.3
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• pp.184-193
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• 1998

In order to dispose radioactive wastes safely, it is needed to understand the mechanical, thermal, fluid behavior of rockmass and physico-chemical interactions between rockmass and water. Also, the knowledge about mechanical and hydraulic properties of rocks is required to predict and to model many conditions of geological structure, underground in-situ stress, folding, hot water interaction, intrusion of magma, plate tectonics etc. This study is based on researches about rock mechanics issues associated with a waste disposal in deep rockmass. This paper includes the mechanical and hydraulic behavior of rocks in varying temperature conditions, thermo-hydro-mechanical coupling analysis in rock mass and deformation behavior of discontinuous rocks. The mechanical properties were measured with Interaken rock mechanics testing systems and hydraulic properties were measured with transient pulse permeability measuring systems. In all results, rock properties were sensitive to temperature variation.

• Toxicological Research
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• v.23 no.4
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• pp.301-309
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• 2007

Paecilomyces tenuipes (PT), one of the Ascomycetes family, has been used for medicinal purposes due to its broad pharmacological activities. The present study was undertaken to investigate the hepatoprotective effects of PT water extracts against $CCl_4$-induced hepatotoxicity in primary cultures of adult rat hepatocytes. When the extract of PT was directly added into the culture medium at 1, 2, and 5 mg/ml, the extracts not only reduce the $CCl_4$-induced elevation of aspartate aminotransferase (AST), alanine aminotransferase (ALT), lactate dehydrogenase, and lipid peroxide, but also protect cultured hepatocytes from $CCl_4$-induced reduction of reduced glutathione, glutathione reductase, glutathione-S-transferase, glutathione peroxidase, catalase and superoxide dismutase. In addition, the effects of PT water extracts on cytochrome P450 enzymes were relatively marginal, indicating that the hepatoprotective effects of PT extract against $CCl_4$-induced toxicity might not be due to the inhibition of $CCl_4$ activation. In conclusion, the PT extracts were effective in protecting against $CCl_4$ induced hepatotoxicity in hepatocyte cultures, at least in part, by scavenging free radicals, and by modulating enzyme systems involved in cellular oxidative stress.

• Journal of Technologic Dentistry
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• v.22 no.1
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• pp.69-78
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• 2000

The microstructure and corrosion behavior of commercially dental casting gold alloys were investigated to clarify the effect of burn-out temperature and cooling rate. In the case of water quenching after casting, only the αphase, which is typical dendritic microstructure of golda alloy, was detected. However, the precipitates along the grain boundary were detected only at the slow cooling rate and they increased inversely proportional to the burn-out temperature. This might be due to the time difference which solute atom could diffuse. EPMA and SEM results also demonstrated that the precipitate should be lamellar structure consisted of Ag rich phase(${\alpha}_1$) and Cu rich phase (${\alpha}_2$). In terms of corrosion, the galvanic coupling was formed due to the difference of composition between precipitates and matrix at the slow cooling rate. In the case of water quenching, the critical current density($i_p$) which indicate the degree of corrosion was lowest at $650^{\circ}C$ and below the burnout temperature, $i_p$ increased with it because of the effect of grain boundary segregation. But above the temperature, $i_p$ increased with it. This may be due to the strain field effect by residual thermal stress.

• Journal of Environmental Health Sciences
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• v.36 no.4
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• pp.279-287
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• 2010

In this study we examined the effects of water extract of garlic on carbon tetrachloride-induced liver injury, and demonstrated increased beneficial enzyme and anti-oxidant activity as well as histopathological changes (by Hematoxylin-Eosin (H&E) staining, Trichrome staining, and TEM examination), and showed that the treatment was dose-dependent and safe. A total of 42 male Sprague-Dawley rats were divided equally (n=7) into six groups. To induce hepatotoxicity in these subjects, carbon tetrachloride diluted in an equal volume of olive oil was intraperitoneally administrated at 0.5 ml/kg (0.20 g/kg/day) once a day for five days. Water extract of Korean-grown garlic was administered via a stomach sonde once a day, 5 days a week, for a total of 4 weeks. Groups received 0.35 g/kg (E1), 0.70 g/kg (E2), or 1.40 g/kg (E3), with the dose adjusted for body weight. Administration of garlic extract resulted in positive physiological effects in terms of reduced oxidative stress and toxicity, and induced functional changes in the liver. Comparing the subject groups (E1, E2, E3) administered different doses of garlic extract, the importance of morphological analysis in further studies is emphasized, because morphological changes indicating hepatotoxicity could occur, even though beneficial enzyme activities were found to be elevated.