• Proceedings of the Korean Society for Environmental Edudation Conference
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• 2002.12a
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• pp.79-85
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• 2002

Inquiry activity contents presented at a chapter on natural environment and our lives in 6 science textbooks of the middle school were analyzed based on kinds of the inquiry Loaming classified by textbook. The number of inquiry activity subjects showed severe variation as mean value was 8.3${\times}$3.7 ranged from 4 to 15. Moreover, textbooks had little common point among each other as the percentage of subjects appeared together in the textbooks more than 3 kinds, 50% of total ones investigated, was just 26.3%. Data interpretation occupied significant position in the inquiry activity as 42% of total activity contents, whereas observation and experiment (or survey) did slight part of the activity as 10% and 16%, respectively even though they are main factors of science education. A model for field education based on the reasonable common subjects was prepared in the Gildong ecological park located In the eastern fringe of Seoul as a plan in order to solve the problems.

• Toxicological Research
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• v.21 no.4
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• pp.291-295
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• 2005

To define the effect of silica on the stimulator of signaling pathway, we studied the phospholipase D (PLD) activity in the Rat2 fibroblasts. Silica stimulated the accumulation of labeled $[^3H]$ phosphatidylethanol$([^3H]\;PEt)$ in a time- and concentration-dependent manner. This Silicainduced PLD activity was partially attenuated by the pretreatment with U73122 (phospholipase C inhibitor), genistein (protein tyrosine kinase inhibitor), PD 98056 (MEK inhibitor) and mepacrine (phospholipase $A_2$ inhibitor). But, sphingosine (protein kinase C inhibitor) and DPI (NADPH reductase inhibitor) had not effect the PLD activity. Silica also increased the PLD activity about four fold, which imply that the PLD activity is more influenced by the mobilization of PLD than other signaling mediators. The PLD activity also partially inhibited calcium chelator EGTA or/and BAPTA/AM compared to silica. Finally, we concluded that a silica-stimulated phospholipase D activity is present in the Rat2 fibroblasts and is modulated by combination of various signaling mediators.

• International Journal of Automotive Technology
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• v.6 no.4
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• pp.333-340
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• 2005

In order to better quantify the contribution from nonroad sources to emission inventories, it is important to understand not only the emissions rates of these engines but also activity patterns that can be used to accurately portray their in-use operation. To date, however, very little information is available on the actual activity patterns of nonroad equipment. In this study, a total of 18 pieces of nonroad equipment were instrumented with collected data including intake manifold air pressure (MAP), exhaust temperature and, on a subset of vehicles, engine rpm and throttle position. The equipment included backhoes, compactors, dozers, motor graders, loaders and scrappers used in applications such as landfilling, street maintenance and general roadwork. The activity patterns varied considerably depending on the type of equipment and the application. Daily equipment operating time ranged from less than 30 minutes to more than 8 hours, with landfill equipment having the highest daily use. The number of engine starts per day ranged from 3-11 lover the fleet with an average of 5 starts per day. The average percent idle time for the fleet was approximately $25\%$ with a range from 11 to $65\%$ for individual pieces of equipment. Duty cycles based on exhaust temperature/throttle position profiles were also developed for two graders and one dozer.

• Journal of Plant Biotechnology
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• v.36 no.3
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• pp.219-223
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• 2009

Oxidative stress derived from excess reactive oxygen species (ROS) is a major damaging factor for plants exposed to environmental stresses. Sweetpotato [Ipomoea batatas (L.) Lam] has a relatively broad adaptability to harsh environmental conditions compared to other staple crops. In this study, to select stress-tolerant sweetpotato cultivars for sources of molecular breeding on marginal lands, we evaluated the ion leakage values in 10 different cultivars after treatment of methyl viologen (MV), an ROS-generating nonselective herbicide, to leaf discs. DPPH radical scavenging activity and the contents of total phenolics were also investigated. The ion leakage of each cultivar showed a diverse value, which is well correlated with DPPH radical scavenging activity of each cultivar. DPPH radical scavenging activity also showed a high corelation with the contents of total phenolic contents. Three cultivars of Yanshu 8, Shinhwangmi and Shinzami showed high antioxidant activity. Our results suggest that a simple and efficient DPPH radical scavenging activity would be a suitable method to select potential cultivars with enhanced tolerance to multiple environmental stress.

• Journal of Microbiology and Biotechnology
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• v.10 no.5
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• pp.656-662
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• 2000

A high level of Staphylococcus haemolyticus L62 lipase was expressed in an Escherichia coli transformant. The expressed lipase activity in the cell-free extract was 70,800 U/l, which corresponded to 30% of the total cellular protein. Pre-mixing of the l62 lipase with some nonionic detergents enhanced its hydrolytic activity towards olive oil: Tween detergents activated the L62 lipase by 3 fold. Gel filtration chromatography of the Tween-80-L62 lipase mixture demonstrated a polymerized complex (∼180 kDa) formed exclusively between Tween-80 and the L62 lipase. The lipase enzyme in the complex showed a higher specific activity towards most triacylglycerols than the intact L62 lipase. The activity enhancement towards each substrate was quite different depending on the acyl chain length; the activity towards tributyrin, trilinolein, and trilinolenin was much more enhanced than the towards the medium and the long-chain saturated triglycerides.

• Advances in nano research
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• v.1 no.2
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• pp.83-91
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• 2013

The synthesis of semiconductor nanoparticles is a growing research area due to the prospective applications for the development of novel technologies. In this paper we have reported the biosynthesis of Cadmium sulfide nanoparticles (CdSNPs) by reduction of cadmium sulphate solution, using the bacteria of Serratia nematodiphila. The process for the synthesis of CdS nanoparticles is fast, novel and ecofriently. Formation of the CdS nanoparticles was confirmed by surface Plasmon spectra using UV-Vis spectrophotometer and absorbance strong peak at 420 nm. The morphology of crystalline phase of nanoparticles was determined from Scanning Electron Microscopy (SEM), Energy Dispersive X-ray spectroscopy and X-ray diffraction (XRD) spectra. The average size of CdS nanoparticles was in the range of 12 nm and the observed morphology was spherical. The results indicated that the proteins, which contain amine groups, played a reducing and controlling responsibility during the formation of CdS nanoparticles in the colloidal solution. Antibacterial activity against some bacteria such as Bacillus subtilis, Klebsiella planticola. CdS nanoparticles exhibiting good bactericidal activity.

• Journal of Environmental Health Sciences
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• v.25 no.3
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• pp.89-93
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• 1999

The purpose of this study finds out the effect of red ginseng extract(1.0 g/kg) on bis(tributyltin)oxide(TBTO)(10, 20 and 40 mg/kg) which poisons against some organs like thyroid gland, liver, kidney, testis, ovary. Serum immunity and sex hormone activity of rats are examined by gastric tubing for 3 weeks. The weights of each in treated group were increased, especially liver in females and those of testis in males were signignificantly increased at 10, 20 and 40 mg/kg (P<0.05, P<0.01). In group treated with TBTO(10, 20 and 40 mg/kg) for females, the serum IgG level was significantly reduced in comparison with control group(P<0.05). The group of females which were poisonned by TBTO and rGe was significantly recovered in TBTO 10 mg/kg + rGe 1.0 g/kg and TBTO 20 mg/kg + rGe 1.0 g/kg. In case of sex hormone activity of each sex, the estradiol activity of females and testosterone activity of males were signignificantly decreased rather than the control group. And control group by bis(tributyltin) oxide and red ginseng extract is just increased estiradiol activity.

• Environmental Analysis Health and Toxicology
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• v.7 no.3_4
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• pp.69-79
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• 1992

Recently, concerns of water pollution and health risks caused by synthetic detergents have emerged, as the use of various detergents has increased It has been suggested that some surfactants are cocarcinogens. The surfactants tested were linear alkylbenzene sulfonate, sodium lauryl sulfate, polyoxyethylene sorbitan monooleat (tween 80), and the mutagens were 1-nitropyrene, N -methyl- N'-nitro-N -nitrosoguanidine, benzo (a) pyrene, and aflatoxin B$_1$. This study was undertaken to investigate the effects of surfactants on the activity of mytagens using the Ames mutagenic assay with Salmonella typhimurium TA98, TA100. The results were summarized as follows: 1. The surfactants have no mutagenic activity of themselves. 2. Higher doses of surfactants than 100 $\mu\textrm{g}$/plate reduced the number of revertants. It is assumed that the reduction would inhibited cell growth. 3. When the comutagenic ratio is defined as the ratio between mutagenic activity itself and the activity with mutagen and surfactant (drinking water quality standard), LAS showed the comutagenic ratio 0.86-1.17 and SLS 0.74-1.10 as well. According to the comparisons, it could not be recognised for the comutagenicity of drinking water quality standard of surfactant. 4. As increasing the amount of mutagens, the designated amount of surfactant did not affected the mutagen's activity statistically. From the above result, syunthetic surfactants do not present mutagenicity and comutagenicity in the microbial assay.

• Korean Journal of Environmental Biology
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• v.21 no.4
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• pp.405-409
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• 2003

To study the tolerant capacity of anaerobic granular sludge (AGS) to oxygen using semi -dynamic batch experiment, the aerating time, pH of the basal media, reductive inorganic materials, microorganism, and microorganism metabolite were investigated. When the aerating time was higher or lower than 0.5 h, the producing gas activity of sludge was lower than that of the control. The oxygen tolerance of the experimental sludge was the highest at the initial pH 7.2. The producing gas activity of sludge I was higher than that of sludge II. And storage at $4^{\circ}C$ can low the lose of the oxygen tolerance capacity of granular sludge. The producing gas activity of sludge was the highest when KI was added. The growth of aerobic microorganisms and some metabolite could increase the producing gas activity of granular sludge.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.27 no.2
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• pp.57-58
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• 2001

Biosurfactant has antibiological activities. Due to its low toxicity, biosurfactant can be applied to human health care products. Posseing the antibiological activities as well as the surfactant properties implies that biosurfactant can be widely used in the cosmetic industry. In this presentation, applications of biosurfactant have been reviewed including the antimicrobial activities of sophorolipid. Sophorolipid, a biosurfactant produced from Candida bombicola ATCC 22214, showed antimicrobial activity against Bacillus subtilis, Staphylococcus xylosus, Streptococcus mutans, and Propionibacterium acne at 4, 1, 1, 0.5 ppm as MIC (minimum inhibitory concentration). Also 100 ppm of sophorolipid inhibited 50% of cell growth of plant pathogenic fungus, B. cinera. However, sophorolipid showed no effect on the Escherichia coli., indicating its selective antimicrobial activity depending on the cell wall structure. Treatment of B. subtilis with sophorolipid increased the leakage of intracellular enzyme, malate dehydrogenase, indicating the possible interaction of sophorolipid with cellular membrane. Between lactone-type and acid-type sophorolipid, the former showed higher antimicrobial activity.