Despite the long history of mushroom use, studies examining the genetic function of mushrooms and the development of new varieties via bio-molecular methods are significantly lacking compared to those examining other organisms. However, owing to recent developments, attempts have been made to use a novel gene-editing technique involving CRISPR/Cas9 technology and genetic scissors in mushroom studies. In particular, research is actively being conducted to utilize ribonucleoprotein particles (RNPs) that can be genetically edited with high efficiency without foreign gene insertion for ease of selection. However, RNPs are too large for Cas9 protein to pass through the cell membrane of the protoplasmic reticulum. Furthermore, guide RNA is unstable and can be easily decomposed, which remarkably affects gene editing efficiency. In this study, nanoparticles were used to mitigate the shortcomings of RNP-based gene editing techniques and to obtain transformants stably. We used Lentinula edodes (shiitake mushroom) Sanjo705-13 monokaryon strain, which has been successfully used in previous genome editing experiments. To identify a suitable osmotic buffer for the isolation of protoplast, 0.6 M and 1.2 M sucrose, mannitol, sorbitol, and KCl were treated, respectively. In addition, with various nanoparticle-forming materials, experiments were conducted to confirm genome editing efficiency via the formation of nanoparticles with calcium phosphate (CaP), which can be bound to Cas9 protein without any additional amino acid modification. RNPs/NP complex was successfully formed and protected nuclease activity with nucleotide sequence specificity.

본 연구에서는 한국에서 개발한 23개의 양송이 품종과 42개의 도입품종의 유전적 다양성과 집단 구조를 SSR 마커를 이용하여 분석하였다. 양송이 품종의 NA는 약 13, HO는 약 0.59, HE는 약 0.74, PIC값은 약 0.71 이었다. 양송이 품종은 군집분석에 의하여 3개의 Group으로 구분되 었고 다양한 국가의 품종으로 구성된 Group2의 다양성이 높았으며, 구조분석에 의하여 2개의 subpopulation으로 구분되었고, 품종의 수가 많은 Pop2의 다양성이 높았다. 한국의 양송이 품종들은 주로 Group 3에 분포하고, subpopulation 간 분포에는 큰 차이를 보이지 않았다. 본 연구의 결과는 양송이의 육종소재의 개발, 다양성 확보 등과 같은 품종의 개발과정에 이용될 수 있을 것이다.

우리나라에서 표고버섯은 소비자의 선호도가 매우 높고, 전체 임산버섯 생산량의 약 97.7%를 차지하고 있는 매우 중요한 단기소득임산물중 하나이다. 이러한 표고버섯은 최근 신품종의 개발이 활발히 이루어지고 있어, 육종가의 권리 보호를 위하여 품종을 구분할 수 있는 분자마커 개발이 요구되고 있다. 본 연구에서는 신품종 ‘산마루2호’를 37개의 표고버섯 품종으로부터 구분할 수 있는 CAPS 마커를 개발하였다. ‘산마루2호’의 유전체에서 Scaffold 2번 1803483에 위치한 단일염기 다형성(SNP)이 확인되었고, 이 SNP를 포함하여 증폭한 DNA는 제한효소 Hhal에 의하여 특이적으로 절단되지 않아 다른 표고버섯 품종들과 구분되었다.

There has been much interest in recycling electronic wastes in order to mitigate environmental problems and to recover the large amount of constituent metals. Silver recovery from electronic waste is extensively studied because of environmental and economic benefits and the use of silver in fabricating nanodevices. Hydrometallurgical processing is often used for silver recovery because it has the advantages of low cost and ease of control. Research on synthesis recovered silver into nanoparticles is needed for application to transistors and solar cells. In this study, silver is selectively recovered from the by-product of electrodes. Silver precursors are prepared using the dissolution characteristics of the leaching solution. In the liquid reduction process, silver nanoparticles are synthesized under various surfactant conditions and then analyzed. The purity of the recovered silver is 99.24%, and the average particle size of the silver nanoparticles is 68 nm.

This study investigated the effect of solvent on the fabrication of Ni-free Fe-based alloy nano powders by employing the PWE (pulsed wire evaporation) in liquid and compared the alloy particles fabricated by three different methods (PWE in liquid, PWE in Ar, plasma arc discharge), for high temperature oxidation-resistant metallic porous body for high temperature soot filter system. Three different solvents (ethanol, acetone, distilled water) of liquid were adapted in PWE in liquid process, while X-ray diffraction (XRD), field emission scanning microscope (FE-SEM), and transmission electron microscope (TEM) were used to investigate the characteristics of the Fe-Cr-Al nano powders. The alloy powder synthesized by PWE in ethanol has good particle size and no surface oxidation compared to that of distilled water. Since the Fe-based alloy powders, which were fabricated by PWE in Ar and PAD process, showed surface oxidation by TEM analysis, the PWE in ethanol is the best way to fabricate Fe-based alloy nano powder.

This study investigated the effect of wire diameter and applied voltage on the fabrication of Ni-free Fe-based alloy nano powders by employing the PWE (pulsed wire evaporation) in liquid, for high temperature oxidation-resistant metallic porous body for high temperature particulate matter (or soot) filter system. Three different diameter (0.1, 0.2, and 0.3 mm) of alloy wire and various applied voltages from 0.5 to 3.0 kV were main variables in PWE process, while X-ray diffraction (XRD), field emission scanning microscope (FE-SEM), and transmission electron microscope (TEM) were used to investigate the characteristics of the Fe-Cr-Al nano powders. It was controlled the number of explosion events, since evaporated and condensed nano-particles were coalesced to micron-sized secondary particles, when exceeded to the specific number of explosion events, which were not suitable for metallic porous body preparation. As the diameter of alloy wire increased, the voltage for electrical explosion increased and the size of primary particle decreased.

This study is aimed to increase the activity of cathodic catalysts for PEMFCs(Polymer Electrolyte Membrane Fuel Cells). we investigated the temperature effect of 20wt% Pt/C catalysts at five different temperatures. The catalysts were synthesized by using chemical reduction method. Before adding the formaldehyde as reducing agent, process was undergone for 2 hours at the room temperature (RT), 40˚C, 60˚C, 80˚C and 100˚C, respectively. The performances of synthesize catalysts are compared. The electrochemical oxygen reduction reaction (ORR) was studied on 20wt% Pt/C catalysts by using a glassy carbon electrode through cyclic voltammetric curves (CV) in a 1M H2SO4 solution. The ORR specific activities of 20wt% Pt/C catalysts increased to give a relative ORR catalytic activity ordering of 80˚C > 100˚C > 60˚C > 40˚C > RT. Electrochemical active surface area (EAS) was calculated with cyclic voltammetry analysis. Prepared Pt/C (at 80˚C, 100˚C) catalysts has higher ESA than other catalysts. Physical characterization was made by using X-ray diffraction (XRD) and transmission electron microscope (TEM). The TEM images of the carbon supported platinum electrocatalysts (80˚C, 100˚C) showed homogenous particle distribution with particle size of about 2~3.5 nm. We found that a higher reaction temperature resulted in more uniform particle distribution than lower reaction temperature and then the XRD results showed that the crystalline structure of the synthesized catalysts are seen FCC structure.

Fe based (FeCSiBPCrMoAl) amorphous powder, which is a composition of iron blast cast slag, were produced by a gas atomization process, and sequently mixed with ductile Cu powder by a mechanical ball milling process. The experiment results show that the as-prepared Fe amorphous powders less than 90 m in size has a fully amorphous phase and its weight fraction was about 73.7%. The as-atomized amorphous Fe powders had a complete spherical shape with very clean surface. Differential scanning calorimetric results of the as-atomized Fe powders less than 90 m showed that the glass transition, T, onset crystallization, T, and super-cooled liquid range T=T-T were 512, 548 and 36, respectively. Fe amorphous powders were mixed and deformed well with 10 wt.% Cu by using AGO-2 high energy ball mill under 500 rpm.

Austenitic oxide-dispersion-strengthened (ODS) stainless steel was fabricated using a wet mixing process without a mechanical milling in order to reduce contaminations of impurities during their fabrication process. Solution of yttrium nitrate was dried after a wet mixing with 316L stainless steel powder. Carbon and oxygen contents were effectively reduced by this wet processing. Microstructural analysis showed that coarse yttrium silicates of about 150 nm were formed in austenitic ODS steels with a silicon content of about 0.8 wt%. Wet-processed austenitic ODS steel without silicon showed higher yield strength by the presence of finer oxide of about 20 nm.

In order to investigate a nitriding process of spent oxide fuel and the subsequent change in thermal properties after nitriding, simulated spent fuel powder was converted into a nitride pellet with simulated fission product elements through a carbothermic reduction process. Nitriding rate of simulated spent fuel was decreased with increasing of the amount of fission products. Contents of Ba and Sr in simulated spent fuel were decreased after the carbothermic reduction process. The thermal conductivity of the nitride pellet was decreased by an addition of fission product element but was higher than that of the oxide fuel containing fission product elements.

The elastic moduli of simulated dry process fuels with varying composition and density were measured in order to analyze the mechanical properties of a dry process fuel pellet. Resonant ultrasound spectroscopy(RUS) which can determine all elastic moduli with one set of measurements for a rectangular parallelepiped sample was used to measure the elastic moduli of UO and simulated dry process fuel. The simulated dry process fuel showed a higher value of Young's modulus than UO due to the presence of metallic precipitates and solid solution elements in the UO matrix. The correlation between Young's modulus and porosity(P) of simulated dry process fuel was found to be 231.4-651.8 P (GPa) at room temperature. Dry process fuel with a higher burnup showed higher Young's modulus because total content of fission product element was increased.