• 한국환경보건학회지
• /
• 제37권1호
• /
• pp.73-79
• /
• 2011

The growing interest in nanotechnology has resulted in increasing concern and a number of published environmental and workplace measurements for assessing occupational exposure to engineered nanomaterials. However, the amount of previous exposure data remains limited. Furthermore the data available was collected with extensive variation in terms of exposure measurement strategy, which limits the ability to pool the data in the future. In response, this paper reviewed several pertinent issues related to exposure measurement strategy to suggest a harmonized measurement strategy which would make exposure data more useful in the future, e.g. correlation between exposure metrics, relationship between activity and exposure, task-based or shift-based assessment, background concentration, limitation of personal exposure monitoring and other determinants of exposure/modeling. An improved sampling strategy for nanomaterial exposure assessment should be considered in order to maximize the use of the data from various real time monitoring instruments.

• 한국식물병리학회:학술대회논문집
• /
• 한국식물병리학회 1998년도 Proceedings of International symposium on Recent Technology of Chemical Control of Plant Diseases
• /
• pp.50-69
• /
• 1998

Dimethomorph is a novel fungicide with a high level of activity against diseases induced by certain Oomycetes, including fungal populations that are resistant to other products. In several ways, this fungicide illustrates the opportunities and challenges presented by many modern pesticides. The specific mode of action, which affects cell wall formation, is associated with a very high level of performance and low dose rates under field conditions. These low dose rates, combined with a low level of toxicity to non-target organisms present an outstanding safety profile. This same highly-specific mode of action, however, limits the spectrum of activity and suggests the need for a resistance management plan, both of which must be addressed in new product development. In addition, the biological and physiochemical properties of this, and other new products are not adequately described by the traditional classification of fungicides into“protectant”and“systemic”types. These unique profiles provide novel and useful products for disease control.

• 한국동물위생학회지
• /
• 제14권1호
• /
• pp.71-77
• /
• 1991

Parathion is widely used in agriculture, but it is highly toxic and now clear that parathion behaves like a cholinergic drug by inhibiting the enzyme cholinesterase. In order to know acute toxicity and the changes of cholinesterase activity according to time lapsed in Sprague-Dawley rats injected single with half dose to LD$_{50}$ of parathion, cholinesterase activities in serum, spinal cord, whole brain and median lethal dose between sex difference were investigated. The results obtained were summerized as follows ; 1. 4LD_{50}$ values of parathion given intraperitoneally to male and female rats were 10.5mg / kg(95% confidence limits, 6.6-16.8mg/ kg) and 3.3mg/ kg(95% confidence limits, 1.9-5.6mg/ kg). 2. The inhibition rate of cholinesterase activities in serum of parathion-injected rats according to time lapsed were peakly decreased to 35.4%(male) and 32.4%(female) after 1 hour in comparison to control group, but cholinesterase activities were completely recovered after 48 hours. 3. The inhibition rate of cholinesterase activities in spinal cord of parathion-injected rats according to time lapsed were peakly decreased to 31.1% (male) and 36.3% (female) after 30 minutes in comparison to control group, but cholinesterase activities were completely recovered after 48 hours. 4. The inhibition rate of cholinesterase activities in whole brain of parathion -injected rats according to time lapsed were peakly decreased to 32.2%(male) and 42.6%(female) after 1 hour in comparison to control group, but cholinesterase activities were completely recovered after 48 hours.s.

• 한국화재소방학회논문지
• /
• 제13권1호
• /
• pp.11-19
• /
• 1999

인화점은 일반적으로 가연성액체의 화재 및 폭발의 위험지수로써 사용된다. 인화점의 구분은 혼합용제와 같은 가연성액체를 안전하게 취급하기 위해서 매우 중요하다. 순수성분 및 혼합용제의 인화점은 라울의 법칙, 달톤의 법칙, 르 샤틀리에 법칙 그리고 활동도계수 모델을 사용함으로써 계산할 수 있다. 본 연구에서는 가연성 2성분계인 메칠에칠케톤과 톨루엔계의 하부인화점과 상부인화점의 실험자룔르 라울의 법칙과 van Laar식에 의해 계산된 값과 비교하였다. 순수물질의 실험자료는 증기압과 폭발한계에 의해 계산된 예측값과 일치하였다. 메칠에칠케톤과 톨루엔계의 하부인화점의 실험자료는 라울의 법칙에 의해 예측된 값과 일치하였고, 상부인화점의 실험자료는 van Laar식에 의해 예측된 값과 일치하였다. 따라서 제시한 방법론에 의해 가연성혼합용제의 인화점 실험자료의 신뢰도 평가가 가능하다.

• 천문학회지
• /
• 제48권5호
• /
• pp.313-323
• /
• 2015

Active galactic nuclei (AGN) are known for irregular variability on all time scales, down to intra-day variability with relative variations of a few percent within minutes to hours. On such short timescales, unexplored territory, such as the possible existence of a shortest characteristic time scale of activity and the shape of the high frequency end of AGN power spectra, still exists. We present the results of AGN single-dish fast photometry performed with the Korean VLBI Network (KVN). Observations were done in a “anti-correlated” mode using two antennas, with always at least one antenna pointing at the target. This results in an effective time resolution of less than three minutes. We used all four KVN frequencies, 22, 43, 86, and 129 GHz, in order to trace spectral variability, if any. We were able to derive high-quality light curves for 3C 111, 3C 454.3, and BL Lacertae at 22 and 43 GHz, and for 3C 279 at 86 GHz, between May 2012 and April 2013. We performed a detailed statistical analysis in order to assess the levels of variability and the corresponding upper limits. We found upper limits on flux variability ranging from ~1.6% to ~7.6%. The upper limits on the derived brightness temperatures exceed the inverse Compton limit by three to six orders of magnitude. From our results, plus comparison with data obtained by the University of Michigan Radio Astronomy Observatory, we conclude that we have not detected source-intrinsic variability which would have to occur at sub-per cent levels.

• Journal of Microbiology and Biotechnology
• /
• 제27권2호
• /
• pp.388-394
• /
• 2017

Although several analytical methods for measuring total antioxidant capacity (TAC) have been applied to biological samples, there were often dissimilar results due to the different principles of methods applied. Thus, this study aimed to validate four conventional analytical methods for measuring plasma TAC, including the ABTS assay, DPPH assay, FRAP assay, and ORAC assay, by comparing with urinary 8-isoprostane concentration. In addition, TAC results were compared with antioxidant enzyme activities including superoxide dismutase (SOD) and glutathione peroxidase in erythrocyte, and catalase in plasma. Plasma TAC measure by ABTS assay was strongly correlated with the result by FRAP assay. Plasma TAC by FRAP and ORAC assays were negatively correlated with erythrocyte SOD activity. The agreement among the four TAC assay methods and 8-isoprostane was determined using 95% prediction limits of linear regression, expressed as the mean of 8-isoprostane ${\pm}95%$ prediction limits. The ABTS method better agreed with 8-isoprostane than the other methods, demonstrating narrow prediction of limits. Furthermore, only plasma TAC determined by the ABTS assay was inversely correlated with urinary 8-isoprostane (r = -0.35, p < 0.05). In summary, the ABTS assay would be an appropriate method to measure overall plasma antioxidant capacity and predict the body's antioxidant status.

• Nuclear Engineering and Technology
• /
• 제49권8호
• /
• pp.1772-1777
• /
• 2017

Korean nuclear power plants (NPPs) periodically evaluate the radioactive gaseous and liquid effluents released from power reactors to protect the public from radiation exposure. This paper provides a comprehensive overview of the release of radioactive effluents from Korean NPPs and the effects on the annual radiation doses to the public. The amounts of radioactive effluents released to the environment and the resulting radiation doses to members of the public living around NPPs were analyzed for the years 2011-2015 using the Korea Hydro & Nuclear Power Co., Ltd's annual summary reports of the assessment of radiological impact on the environment. The results show that tritium was the primary contributor to the activity in both gaseous and liquid effluents. The averages of effective doses to the public were approximately on the order of $10^{-3}mSv$ or $10^{-2}mSv$. Therefore, even though Korean NPPs discharged some radioactive materials into the environment, all effluents were within the regulatory safety limits and the resulting doses were much less than the dose limits.

• Journal of Periodontal and Implant Science
• /
• 제26권3호
• /
• pp.715-724
• /
• 1996

This study was performed to identify the proliferation and to measure the alteration of alkaline phosphatase activity in human gingival fibroblasts cultured. For the present study, the authors cultured the human gingival fibroblasts oriented from the sound interdental gingiva, and used third passage. It was used methyl $[^3H]$ Thymidine to identify the proliferation in human gingival fibroblasts and used 410nm of the spectrophotometer to measure the alteration of the alkaline phosphatase activity in human gingival fibroblasts. The results were as follows: 1. There was a statistically significant increase in the proliferation of gingival fibroblasts following low level laser irradiation at 24 hour(p<0.05). 2. There was a statistically significant increase in activity of alkaline phosphatase compared to control group at 5-day laser irradiation after in laser irradiation groups(p<0.05). And there was a statistically significant increase in activity of alkaline phosphatase compared to control group at 7-day laser irradiation after in the I-minute laser irradiation group(p<0.05), but there was a statistically significant decrease in activity of alkaline phosphatase compared to 1minute laser irradiation group at 7-day laser irradiation in the 2-minute laser irradiation group after(p<0.05). The results, within the limits of the present experiments, suggest that, the low level laser irradiation accelerates the proliferation of gingival fibroblasts and alters the alkaline phosphatase activity until the restricted period.

• 한국응용과학기술학회지
• /
• 제32권1호
• /
• pp.127-135
• /
• 2015

The aim of this study was to investigate the antioxidant activity of thermal treatment yam (Dioscorea batatas DECNE.) in Korea. Thermal treatment yam was extracted by different solvents including 70% methanol, 70% ethanol and chloroform-methanol mixture (CM, 2:1, v/v). Then color property, total phenol content and antioxidant activity were analyzed. Yam possessed high $L^*$ value and $H\limits^{\circ}$ value, which were $54.92{\pm}2.18$ and $73.20{\pm}0.77$, respectively. Thermal treatment yam exhibited great antioxidant activity evaluated by ABTS [2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt] radical scavenging activity, DPPH (2,2-diphenyl-1-picrylhydrazyl) radical scavenging activity, reducing power, and ferric reducing antioxidant power. Total phenol contents of various extracts from thermal treatment yam increased in the following order: 70% methanol extract ($63.53{\pm}0.33mg\;CAE/g$), 70% ethanol extract ($69.47{\pm}1.00mg\;CAE/g$) and CM extract ($97.49{\pm}0.66mg\;CAE/g$), respectively. The same trend was also could be found in antioxidant activity assays except for reducing power assay. These results implied that these extracts from thermal treatment yam might be useful to take a good part in prevention of human diseases and aging.

• 한국전문물리치료학회지
• /
• 제26권4호
• /
• pp.35-41
• /
• 2019

Background: Obstacle training affects lower limb muscle activity, balance, reducing the risk of falls, and making gait more stable. Objects: This study aimed to investigate the effects of aquatic and ground obstacle training on balance and muscle activity in patients with chronic stroke. Methods: The study subjects included 30 patients with stroke, who were divided into aquatic ($n_1=15$) and ground ($n_2=15$) groups. Groups underwent obstacle training three times per week, 30 min per session, for six weeks that went as follows: walking over sites with the paralyzed leg, stepping onto and down from a box step, and walking over obstacles with the non-paralyzed leg. Results: The experimental results were obtained by comparing muscle activity. Activity of the rectus femoris, biceps femoris, tibialis anterior, and gastrocnemius were significantly increased in the aquatic group (p<.05). Activity of the biceps femoris and tibialis anterior were significantly increased in the ground group (p<.05); however, the rectus femoris and gastrocnemius were not significantly different. In the comparison of maximal distance regarding the limits of stability, it was significantly increased on the non-affected side, affected side, and anterior and posterior distance in the aquatic group (p<.05). It was significantly increased in the non-affected side and anterior and posterior distance the ground group (p<.05); however, maximal distance on the affected side distance was not significantly different. Conclusion: Gait training with aquatic and ground obstacles is effective for improving balance and gait ability of patients with stroke. However, it was more effective for the aquatic group than for the ground group.