• Korean Journal of Microbiology
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• v.52 no.3
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• pp.278-285
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• 2016

The bifunctional PheA protein, having chorismate mutase and prephenate dehydratase (CMPD) activities, is one of the key regulatory enzymes in the aromatic amino acid biosynthesis in Escherichia coli, and is negatively regulated by an end-product, phenyalanine. Therefore, PheA protein has been thought as useful for protein engineering to utilize mass production of essential amino acid phenylalanine. To obtain feedback resistant PheA protein against phenylalanine, we mutated by using random mutagenesis, extensively screened, and obtained $pheA^{FBR}$ gene encoding a feedback resistant PheA protein. The mutant PheA protein contains substitution of Leu to Phe at the position of 118, displaying that higher affinity (about $290{\mu}M$) for prephenate in comparison with that (about $850{\mu}M$) of wild type PheA protein. Kinetic analysis showed that the saturation curve of $PheA^{FBR}$ against phenyalanine is hyperbolic rather than that of $PheA^{WT}$, which is sigmoidal, indicating that the L118F mutant enzyme has no cooperative effects in prephenate binding in the presence of phenylalanine. In vitro enzymatic assay showed that the mutant protein exhibited increased activity by above 3.5 folds compared to the wild type enzyme. Moreover, L118F mutant protein appeared insensitive to feedback inhibition with keeping 40% of enzymatic activity even in the presence of 10 mM phenylalanine at which the activity of wild type $PheA^{WT}$ was not observed. The substitution of Leu to Phe in CMPD may induce significant conformational change for this enzyme to acquire feedback resistance to end-product of the pathway by modulating kinetic properties.

• The Korean Journal of Air & Space Law and Policy
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• v.33 no.1
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• pp.175-204
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• 2018

Recently, the aviation leisure business has been legislated, and related industries have become active base with increasing the light sports aircraft within the legislation system. However, in the light sports aircraft safety problem, it is often mentioned that the flight is in violation of the regulations, the lack of safety consciousness of the operator and lack of ability, and the personal operators have a risk of accident of light aircraft such as insufficient safety management and poor maintenance. At present, the maintenance of light sports aircraft is carried out by the A & P mechanic in accordance with the relevant laws and regulations, but it is difficult to say that it is equipped with qualification and expertise. It is not a legal issue to undertake light sports aircraft maintenance work on the regulation system. However, the problem of reliability and appropriateness is constantly being raised because airplanes, light sports aircraft, and ultra-light vehicle are classified and serviced in a legal method. Although legal and institutional frameworks for light sports aircraft are separated, much of it is stipulated in the aviation law provisions. Light sports aircraft maintenance work also follows the current aircraft maintenance system. In the United States, Europe, and Australia where General Aviation developed, legal and institutional devices related to maintenance of light aircraft were introduced, and specialized maintenance tasks are covered in the light aircraft mechanics system. As a result of analysis of domestic and foreign laws and regulations, it is necessary to introduce the qualification system for maintenance of light aircraft. In advanced aviation countries such as the United States, Europe, and Australia, a light sports aircraft repairman system is installed to perform safety management. This is to cope with changes in the operating environment of the new light sports aircraft. This study does not suggest the need for a light aircraft repairman system. From the viewpoint of the legal system, the examination of the relevant laws and regulations revealed that the supplementary part of the system is necessary. It is also require that the necessity of introduction is raised in comparison with overseas cases. Based on these results, it is necessary to introduce the system into the light aircraft repairman system, and suggestions for how to improve it are suggested.

• Journal of the Korean Society for Marine Environment & Energy
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• v.9 no.4
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• pp.243-252
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• 2006

Influence of the increasing carbon dioxide concentration in seawater on various marine organisms is assessed in this article with regard to the impacts of anthropogenic $CO_2$ introduced into surface or deep oceans. Recent proposals to sequester $CO_2$ in deep oceans arouse the concerns of adverse effects of increased $CO_2$ concentration on deep-sea organisms. Atmospheric introduction of $CO_2$ into the ocean can also acidify the surface water, thereby the population of some sensitive organisms including coral reefs, cocolithophorids and sea urchins will be reduced considerably in near future (e.g. in 2100 unless the increasing trend of $CO_2$ emission is actively regulated). We exposed bioluminescent bacteria and benthic amphipods to varying concentrations of $CO_2$ and also pH for a short period. The ${\sim}l.5$ unit decrease of pH adversely affected test organisms. However, amphipods were not influenced by decreasing pH when HCl was used for the seawater acidification. In this article, we reviewed the biological adverse effects of $CO_2$ on various marine organisms studied so for. Theses results will be useful to predict the potential risks of the increase of $CO_2$ concentrations in seawater due to the increase of atmospheric $CO_2$ emission and/or sequestration of $CO_2$ in deep oceans.

• Korean Journal of Environment and Ecology
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• v.24 no.2
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• pp.157-165
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• 2010

This study was carried out to suggest the basic data of planting method for construction of buffer green space based on the land use in case of reclaimed land by analyzing land structure, planting concept, and planting structure in buffer green space, Rokko Island, Kobe, Japan. Rokko Island(total area: 580ha) is divided into port and logistics industry area and urban area by constructing the box type large-scale buffer green space. The land structure of buffer green space were biased mounding type, parallel mounding type, and complex mounding type. The width of buffer green space was 50meters in case of northern area, from 28 to 32meters in case of eastern area, and 37.5meters in case of western area, and the slope of that was from 18 to 25 degrees and the height of that was from 2 to 15meters. There were applied landscape and buffer planting concept on the sea side area of northern buffer green space, on the other hand landscape and shade planting concept on the Inner city side area of that. According to the result of planting structure analysis of northern buffer green space, the main woody species were those of deciduous-evergreen species grow in warm-temperate forest zone such as Quercus glauca, Cinnamomum camphora, Machilus thunbergii, Elaeagnus maritima. The results of maximum number of species and planting density by $100mm^2$ was that 9 species 22 individuals in canopy layer, 9 species 15 individuals in understory layer, 3 species 67 individuals in shrub layer, and 14 species 104 individuals in total. The plant coverage of northern buffer green space based on the ecological planting method was from 69 to 139% in case of canopy layer, from 26 to 38% in case of understory layer, from 6 to 7% in case of shrub layer, and from 101 to 184% in total. Index of plant crown volume of northern buffer green space based on the ecological planting method was from 1.40 to $3.12m^3/m^2$ in case of canopy layer, from 0.43 to $0.55m^3/m^2$ in case of understory layer, $0.06m^3/m^2$ in case of shrub layer, and from 1.89 to $3.73m^3/m^2$ in total.

• Korean Journal of Optics and Photonics
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• v.27 no.1
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• pp.1-17
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• 2016

Over the past two decades, fiber-based lasers have made remarkable progress, now having reached power levels exceeding kilowatts and drawing a huge amount of attention from academy and industry as a replacement technology for bulk lasers. In this paper we review the significant factors that have led to the progress of fiber lasers, such as gain-fiber regimes based on ytterbium-doped silica, optical pumping schemes through the combination of laser diodes and double-clad fiber geometries, and tandem schemes for minimizing quantum defects. Furthermore, we discuss various power-limitation issues that are expected to incur with respect to the ultimate power scaling of fiber lasers, such as efficiency degradation, thermal hazard, and system-instability growth in fiber lasers, and various relevant methods to alleviate the aforementioned issues. This discussion includes fiber nonlinear effects, fiber damage, and modal-instability issues, which become more significant as the power level is scaled up. In addition, we also review beam-combining techniques, which are currently receiving a lot of attention as an alternative solution to the power-scaling limitation of high-power fiber lasers. In particular, we focus more on the discussion of the schematics of a spectral beam-combining system and their individual requirements. Finally, we discuss prospects for the future development of fiber laser technologies, for them to leap forward from where they are now, and to continue to advance in terms of their power scalability.

• Journal of the Korean Society of Food Science and Nutrition
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• v.38 no.11
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• pp.1571-1579
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• 2009

Antioxidant activities of ethanol and water extracts from Orostachys japonicus leaf, stem, and root were determined by rancimat method, DPPH radical scavenging effect, chelating effect, and reducing power analysis. The highest total phenolic compound (TPC) as 14.6 mg/g of dry sample and the strongest antioxidant activity in rancimat method (value of AI 1.98), DPPH radical scavenging effect (96% in 4 mg/mL), and reducing power (1.50 in 4 mg/mL) were observed in ethanol extracts from Orostachys japonicus leaf. Heat and pH stabilities on antioxidant activity of Orostachys japonicus leaf extract were studied through TPC and DPPH radical scavenging effect. As a result, the extracts from Orostachys japonicus leaf showed high stability. These results suggest that extracts from Orostachys japonicus leaf can be potentially used as proper natural antioxidant in the food industry.

• Journal of the Korean Society of Food Science and Nutrition
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• v.43 no.8
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• pp.1236-1247
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• 2014

Gamma irradiated-treatment of natural medicinal plants can be used to improve extraction transference number and for qualitative improvement of color when applied to functional material exploration. This study investigated the biological activities of Aralia elata cortex extracts upon gamma irradiation. In addition, different physical techniques [photostimulated luminescence (PSL) and thermoluminescence (TL)] were used for irradiation identification of Aralia elata cortex. In PSL analysis, non-irradiated (0 kGy) sample showed a negative result of 400 photon counts (PCs), whereas irradiated (5, 10, and 30 kGy) samples showed positive results of 90,100.00, 312,614.33, and 321,661.67 PCs, respectively. In the TL method, growth curve showed very unusual behaviors around $200^{\circ}C$ upon natural-irradiation of the non-irradiated (0 kGy) sample and around $150{\sim}250^{\circ}C$ for the irradiated (5, 10, and 30 kGy) samples. The TL ratio was 0.1 in non-irradiated samples at 0.011, whereas the values of irradiated samples (5, 10, and 30 kGy) were 0.1 at 1.105, 1.009, and 2.206, respectively. For phenolics of gamma-irradiated Aralia elata cortex, water and 50% ethanol extracts had the highest amounts, $17.30{\pm}0.40mg/g$ and $18.87{\pm}0.46mg/g$ at 10 kGy irradiation, respectively. The inhibitory activities of angiotensin-converting enzyme and xanthin oxidase were higher in both irradiated water and 50% ethanol extracts than in non-irradiated ones. For pancreatin ${\alpha}$-amylase and ${\alpha}$-glucosidase inhibitory activities, water and 50% ethanol extracts containing $200{\mu}g/mL$ of phenolics showed high inhibitory activities of 60~100% at all irradiation doses (0~30 kGy). This result confirmed that Aralia elata cortex extracts have greater anti-diabetic effects than acabose as a diabetic remedy. Gamma-irradiated Aralia elata cortex extracts are useful as a functional material with anti-diabetic effects. Thus, Aralia elata cortex extracts can be used as a functional material with various biological activities, and gamma-irradiation can be used to amplify biological activities in plants.

• The Korean Journal of Air & Space Law and Policy
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• v.23 no.1
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• pp.83-109
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• 2008

According to 1944 Chicago Convention aircraft are classified into public aircraft(or state aircraft) and private aircraft(or civil aircraft). However even if public aircraft owned by government are used as commercial flights, those are classified into private aircraft. But as far as space activities are concerned in the 1967 Outer Space Treaty, those are related to all activities and all space objects, thus there being no differentiation between the public spacecraft and private spacecraft. As for the institutions of air law there are ICAO, IATA, ECAC, AFCAC, ACAC, LACAC in the world. However in the field of space law there is no International Civil Space Organization like ICAO. There is only COPUOS in the United Nations. The particular institutions such as INTELSAT, INMARSAT, ITU, WIPO, ESA, ARABSAT would be helpful to space law field. In the near future there is a need to establish International Civil Space Organization to cover problems rising from all space activities. According to article 1 of the 1944 Chicago Convention the contracting States recognize that every State has complete and exclusive sovereignty over the airspace above its territory. It means that absolute airspace sovereignty is recognized by not only the treaty law and but also customary law which regulates non-contracting States to the treaty. However as for the space law in the article n of the 1967 Space Treaty outer space, including the moon and other celestial bodies, is not subject to national appropriation by claim of sovereignty, by means of use or occupation, or by any other means. It creates res extra commercium like the legal status of high seas in the law of the sea. However the 1979 Moon Agreement proclaimed Common Heritage of Mankind as far as the legal status of the outer space is concerned which is like the legal status of deep sea-bed in the 1982 United Nations Law of the Sea. As far as the liabilities of air transport system are concerned there are two kinds. One is the liabilities to passenger on board aircraft and the other is the liabilities to the third person or thing on the ground by the aircraft. The former is regulated by the Warsaw System, the latter by the Rome Convention. As for the liabilities of space law the 1972 Liability Convention applies. The Rome Convention and 1972 Liability Convention stipulate absolute liability. In the field of space transportation there would be new liability system to regulate the space passengers on board spacecraft like Warsaw System in the air transportation.

• Particle and aerosol research
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• v.11 no.3
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• pp.63-75
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• 2015

Atmospheric environment in Korea is influenced by outside, especially China. The concentrations of air pollutants in China have showed decreasing trends since 2000. However, these concentration levels in China are still higher than other developed countries. The Chinese Government has tried several measures to control the air pollution. In this study, the details of the amendments and smog reduction strategies in China, especially for Beijing are reviewed and the strategies for Korean side to promote cooperation in Northeast Asia are suggested and discussed. The Chinese State Council amended the Environmental Protection Provisions and Clean Air Act and announced The Action Plan for Air Pollution Control (2013-2017), focusing on three key regions, Beijing-Tianjin-Hebei area (Jing-Jin-Ji), Yangtze River Delta (YRD) and Pearl River Delta (PRD). These policy actions and plan are mainly for the reducing coal usage and emissions from vehicles. It is suggested that, Korea should actively promote multi-national cooperation in the region to take an initiative role in environmental areas.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.36 no.1
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• pp.120-128
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• 2018

The purpose of this study is to establish basic data for the continuous protection management policy of domestic natural world heritage and mixed world heritage, and to examine the present situation and characteristics of the protection management according to the World Heritage Convention on the World Heritage listed Huangshan. The results of this study are as follows. First, Huangshan began to be protected by the establishment of the Huangshan Construction Committee in 1933, and after the designation of national park in 1982, laws and regulations were established in the central ministries, And various projects related to utilization have been implemented. Secondly, the establishment of the boundary for protection was actively intervened by the central government, such as the reorganization of the boundary of Huangshan through the administrative district plan. In order to protect the ecological and landscape value as well as the cultural factor, And designated a heritage designated area. Third, the protection management of Huangshan was divided into four major stages. The first phase was divided into the period when administrative measures were taken to manage the protection of Huangshan. The second phase was designated as a national park in Huangshan. The third period was the time of the protection-oriented project according to the recommendation of the international organizations after the World Heritage listed. The fourth period was the expansion of the tourism industry for the continuous use of protection of Huangshan city, My preservation business was being implemented. Fourth, Huangshan is managed by the central government and the city government. Huangshan, which is a mixed heritage, is managed jointly by the Ministry of Cultural Heritage Administration and the Ministry of Natural Heritage Administration. The protection and management of Huangshan promoted the efficiency and expertise of the heritage-related work through the establishment of the administrative unit-specific management system, and the local governments were entrusted with the authority to implement the protection management policies that meet local characteristics. Fifth, the preservation area of Huangshan has been destroyed by the development policy centered on the mountain. In addition, according to the operation of accommodation facilities, there are problems such as sewage, garbage disposal, and environmental pollution caused by tourists, and the damage caused by pests and diseases in planted plantations around the area and changes in ecosystem due to the composition of cable cars. Sixth, for the continuous protection of Huangshan, strict regulations on new construction, extension and management of accommodation are required, and it is necessary to install facilities to limit and control the number of visitors.