• Polymer(Korea)
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• v.31 no.6
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• pp.505-511
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• 2007

Poly(lactide-co-glycolide)(PLGA) and hyaluronic acid (HA) has been widely used as biocompatible scaffold materials to regenerate tissue. In this present study, we fabricated microporous PLGA and HA loaded PLGA scaffolds by a emusion freeze-drying method. In order to confirm that the release profile of cytokine or water-soluble drugs, we manufactured the granulocyte macrophage colony stimulating factor(GM-CSF) loaded PLGA and HA-PLGA scaffold. All scaffolds were characterized using scanning electron microscope(SEM), mercury porosimeter and wettability measurement. Cell proliferation and viability were assessed by a 3-(4,5-dimethylthiazole-2-yl)-2,5-diphenyltetrazolium-bromide (MTT) test. The porosity of HA-PLGA scaffold was greater than 95% with the total pore area of $261\;m^2/g$. The HA-FLGA scaffold exhibited well interconnected pores to allow greater cell adhesion and prolixferation. It was proven by higher cell viability in the HA-PLGA scaffold than PLGA alone. This may be due to the enhanced natural properties and higher water retention capacity of HA.

• Korean Journal of Weed Science
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• v.12 no.4
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• pp.387-392
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• 1992

For reducing the residual effects of Quinclorac to followed-by crops of paddy rice, three tests by different soil improvers, different cultural performances with tillage and application of composts, and cultivation of different depletion crops were evaluated, respectively. Among seven soil improvers, activated carbon, composts and perlite showed significant promisable feasibility to reduce phytotoxicity of tomato seedlings as affected by Quinclorac residuals, And comparing to untreated check, the application of tillage and composts prior to transplanting of tomato seedling could helpful to reduce Quinclorac residuals in the soil, but tomato and lettuce, most susceptible crops to Quinclorac, were not remarkably protected by those cultural performances. Also among cultivation of depletion crops just after rice harvest, Italian ryegrass, tall fescue, rape and oats engaged to deplete and reduce Quinclorac residuals for tomato seedling growth, however alfalfa and hairy vetch, relatively susceptible plants to Quinclorac were not promisable.

• Korean Journal of Soil Science and Fertilizer
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• v.35 no.5
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• pp.314-325
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• 2002

The effects of arbuscular mycorrhizal (AM) fungus (Glomus intraradices) on plant growth and N metabolic responses were examined in perennial ryegrass plants exposed to drought-stressed or well-watered condition. Mycorrhizal inoculation improved significantly leaf water potential, dry mass and P content. Drought stress increased significantly nitrate concentration in roots where the increase was much less in AM than non-AM. Drought stress decreased the concentration of soluble proteins in non-AM shoots, whereas non-significant decline occurred in AM shoots even under drought condition. The concentrations of ammonia and proline in drought stressed non-AM plants significantly increased, while mycorrhizal inoculation lowered significantly ammonia and proline accumulation. The decrease in leaf dry weight in drought stressed-plants was significantly correlated to the increase in ammonia (p<0.01) and proline concentration (p<0.01). These results suggested that the increased P content and N assimilation by mycorrhizal inoculation may be associated with drought stress tolerance, showing the moderating effects on shoot growth inhibition and ammonia accumulation in drought stressed-plants.

• Food Science and Preservation
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• v.12 no.5
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• pp.482-488
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• 2005

Oxidant stress is well-known for a pivotal parameter related to neuro-inflammatory diseases including Alzheimer's disease, Parkinson's disease, and ALS (Lou Gehrig's disease). In order to effectively screen for anti-inflammatory agents, we first established the infrastructure of high throughput screening for anti-oxidant agents from medicinal insect library extracted with water, methanol, ethanol, and dimethyl sulfoxide. By the screening system, we found that Tenodera angustipennis Saussure, Pyrocoela rupa Olivier and Papilio maackii Mntris had strong anti-oxidant activity. Moreover, Tenodera angustipennis Saussure and Tenodera aridifolia (Stoll) exhibited protection effects of cellular damage by treatment of an oxidant hydrogen peroxide. Together, the results suggest that some selected hits could be a potential agent against neuro-inflammation, although the in vivo studies should be clearly tested.

• Food Science and Preservation
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• v.17 no.1
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• pp.117-122
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• 2010

We investigated the effect of rice particle size on the physicochemical properties of fish porridge. The pH of porridge did not differ with particle size. The redness, yellowness, and viscosity of fish porridge increased as particle size increased. The protein content of fish porridge was increased three-fold, compared with that of porridgethat did not contain fish. The total amino acid content of fish porridge was 1,610.5 mg/100 g and that of rice porridge 1,147.5 mg/100g. The Lysand Thr (these are limiting amino acids in rice) contents of fish porridge were greater than in rice porridge. In sensory evaluation tests, half-grain rice fish porridge obtained the highest scores. Based on these results, we would suggest that fish porridge made using half-grain rice has valuable physicochemical and nutritional properties.

• Korean Journal of Microbiology
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• v.48 no.2
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• pp.125-133
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• 2012

Anaerobic digestion is an alternative method to digest food wastes and to produce methane that can be used as a renewable energy source. We investigated bacterial and archaeal community structures in a three-stage methane production process using food wastes with concomitant wastewater treatment. The three-stage methane process is composed of semianaerobic hydrolysis/acidogenic, anaerobic acidogenic, and strictly anaerobic methane production steps in which food wastes are converted methane and carbon dioxide. The microbial diversity was determined by the nucleotide sequences of 16S rRNA gene library and quantitative real-time PCR. The major eubacterial population of the three-stage methane process was belonging to VFA-oxidizing bacteria. The archaeal community consisted mainly of two species of hydrogenotrophic methanogen (Methanoculleus). Family Picrophilaceae (Order Thermoplasmatales) was also observed as a minor population. The predominance of hydrogenotrophic methanogen suggests that the main degradation pathway of this process is different from the classical methane production systems that have the pathway based on acetogenesis. The domination of hydrogenotrophic methanogen (Methanoculleus) may be caused by mesophilic digestion, neutral pH, high concentration of ammonia, short HRT, and interaction with VFA-oxidizing bacteria (Tepidanaerobacter etc.).

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.40 no.5
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• pp.197-203
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• 2003

In this paper, we have presented millimeter-wave high conversion gain quadruple subharmonic mixers adopting the cascode harmonic generator The subharmonic mixers were successfully integrated by using 0.1 ${\mu}{\textrm}{m}$ GaAs pseudomorphic HEMTs(PHEMTs) and coplanar waveguide(CPW) structures. Measured output of 1st, 2nd and 4th harmonics of the fabricated cascode 4th harmonic generator are -21.42 dBm, -32.65 dBm and -13.45 dBm, respectively, for an input power of 10 dBm at 14.5 GHz. We showed that the highest conversion gain of 3.4 dB has obtained thus far at a LO power of 13 dBm from the fabricated subharmonic mixers. The millimeter-wave subharmonic mixer also ensure a high degree of isolation showing -53.6 dB in the LO-to-IF and -46.2 dB in the LO-to-RF, respectively, at a frequency of 14.5 GHz. The high conversion gain achieved in this work is the first report among the millimeter-wave subharmonic mixers.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.41 no.4
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• pp.51-61
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• 2004

In the dental field, the 3D tooth model in which each tooth can be manipulated individually is an essential component for the simulation of orthodontic surgery and treatment. To reconstruct such a tooth model from CT slices, we need to define the accurate boundary of each tooth from CT slices. However, the global threshold method, which is commonly used in most existing 3D reconstruction systems, is not effective for the tooth segmentation in the CT image. In tooth CT slices, some teeth touch with other teeth and some are located inside of alveolar bone whose intensity is similar to that of teeth. In this paper, we propose an image segmentation algorithm based on B-spline curve fitting to produce smooth tooth regions from such CT slices. The proposed algorithm prevents the malfitting problem of the B-spline algorithm by providing accurate initial tooth boundary for the fitting process. This paper proposes an optimal threshold scheme using the intensity and shape information passed by previous slice for the initial boundary generation and an efficient B-spline fitting method based on genetic algorithm. The test result shows that the proposed method detects contour of the individual tooth successfully and can produce a smooth and accurate 3D tooth model for the simulation of orthodontic surgery and treatment.

• Journal of the Korean Association of Geographic Information Studies
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• v.11 no.3
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• pp.166-173
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• 2008

Recently, problem of earth environment being attended with international issue, people are concerned about the environmentally-friendly and renewable biomass energy. Especially, the forest biomass is more important because Korea have to control carbon footprint for Kyoto Protocol and Convention on Climate Change. In case of Korea, forest area covers the land about 2/3 of all country. It is needed that more economical and efficient method to estimate the biomass by remote sensing data which include wide coverage and is progressed by one-step. In this study, we estimate forest biomass with LiDAR data and aerial photograph. Three biomass equation is used and estimate mean biomass of single tree and entire biomass in plots. The results are compared with field data. $R^2$ of the mean biomass of single tree is greater than 0.8 and that of entire biomass in plots is greater than 0.65. In conclusion, the method using remote sensing data is verified more economical and efficient than previous field data method.

• International Commerce and Information Review
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• v.2 no.1
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• pp.129-148
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• 2000

지적재산권은 기술개발의욕 자극을 위해 새로이 물건이나 사상 등의 창작자에게 일종의 배타적 독점권을 부여한 것으로서 1980년대 이후 국제적 관심이 고조되기 시작하였는데, 두 차례의 석유파동 이후 기술이 국제 경쟁력의 주요 결정요인으로 등장하던 시기에 한국을 비롯한 개도국들이 선진국의 기술을 모방하여 첨단기술제품 분야에서 경쟁적 우위를 확보하자 자신들의 경쟁력 확보를 위해 선진국들이 자신들의 통상교섭력을 바탕으로 GATT/UR 등 국제적 협상을 통해 지적재산권 보호문제를 통상문제로 확대시킨 것이다. 이러한 지적재산권에 대한 통상문제와 관련하여 가장 문제가 되는 국가는 역시 미국인데, 미국은 통상법 301조 중 지적재산권 보호에 적용되는 Special 301조를 이용하여 지적재산권 보호에 대한 실효성을 확보하였으며, 당초 제품수입상의 불공정거래행위에 적용하던 관세법 337조를 지적재산권을 침해하는 수입 판매행위에도 적용할 수 있도록 개정함으로써 그 보호수단을 더욱 강화하였는데, 이에 따라 우리도 적절한 대응방안의 모색이 요구되고 있다. 우선 정부의 입장에서는 대내적으로 원천기술 및 개량기술 개발을 통한 기술의 해외의존도 축소, 인센티브 도입 등 직무발명제도 활성화, 해외특허권 취득확대를 위한 중소기업의 해외출원비용 지원, 심사관의 전문화롤 통한 심사의 처리속도 및 질 향상, 특허기술정보 이용체제 개선을 위한 특허청의 정보전산화 및 산업기술정보원 톡허정보센타와의 유기적인 협조체제 구축, 기업의 특허분쟁대응능력 향상을 위한 전담부서 마련 및 국제특허분쟁 전문변리사 양성 등의 대안을 마련할 필요가 있으며, 대외적으로는 PLT협약 등 차후에 있을 국제협약에의 적극적인 참여를 통한 우리나라의 이익도모, 남북 가교역할의 강화 및 한 미 양국간의 법제적 차이에 대한 오해불식, 해당 산업에 영향을 줄 수 있는 로비 활동의 활성화 등의 대안이 필요하다. 또한 기업의 입장에서는 사전적으로 과감한 연구개발투자를 통한 산업재산권 확보, 기술 법률 언어능력을 고루 갖춘 특허전문가의 확보, 국제특허분쟁에 대한 대응체계 구축, 특허권 분쟁발생 방지를 위한 책임소재의 명확화 등의 근본적인 대책과 국제특허분쟁 차단을 위한 철저한 선행기술 조사, 해외기술의 개량 및 이용 촉진을 위한 크로스-라이센스의 활성화, 부실특허권에 대한 적극적인 무효심판청구, 제소정보에 대한 조기 입수, 설계변경이나 특허무효자료조사 등 침해회피 방법의 준비, 위험특허에 대한 철저한 예비조사 등의 부수적인 대책을 마련할 필요가 있으며, 일단 특허분쟁이 발생한 경우에는 당해 분쟁의 자사 생산 제품과의 관련여부 검토, 사건에 필요한 광범위한 정보 수집을 위한 전담팀 구성, 제소인의 특허권에 대한 면밀한 법률적 검토, 제소자에 대한 정확한 정보파악 및 최종 대응방안에 대한 신속한 결정, 자사의 특허를 이용한 제소자에 대한 역제소 등의 대응방안을 강구할 필요가 있는 것이다.