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Adenosine monophosphate enhances callus regeneration competence for de novo plant organogenesis

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Molecular Plant 2023年第12期16卷 1867-1870页

作者： Hong Gil Lee Seo Young Jang Eun Yee Jie Seung Hee Choi Ok-Sun Park soon hyung bae Hyun-soon Kim Suk Weon Kim Geum-Sook Hwang Pil Joon Seo Department of Chemistry Seoul National UniversitySeoul 08826Korea Plant Genomics and Breeding Institute Seoul National UniversitySeoul 08826Korea Integrated Metabolomics Research Group Western Seoul CenterKorea Basic Science InstituteSeoul 03759Korea Biological Resource Center Korea Research Institute of Bioscience and BiotechnologyJeongeup56212Korea Plant Systems Engineering Research Center Korea Research Institute of Bioscience and BiotechnologyDaejeon 34141Korea College of Pharmacy Chung-Ang UniversitySeoul 06974Korea

Dear Editor,Plant tissue culture involves callus formation and de novo shoot ***,explants from differentiated tissues are used to generate a pluripotent cell mass,called callus,on auxin-rich callus-inducing medium(CIM),followed by shoot regeneration on cytokinin-rich shoot-inducing medium(SiM).Callus results from division of pericycle-like cells(Atta et al.,2009;Sugimoto et al.,2010);its cellular identity resembles that of lateral root primordia(Atta et al.,2009;Sugimoto et al.,2010).Callus acquires cellular pluripotency by forming root stem cell niches on CIM(Sugimoto et al.,2010)。

关键词： Adenosine callus

Superior mechanical properties and strengthening mechanisms of lightweight AlxCrNbVMo refractory high-entropy alloys(x=0,0.5,1.0)fabricated by the powder metallurgy process

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Journal of Materials Science & Technology 2021年第10期69卷 32-41页

作者： Byungchul Kang Taeyeong Kong Ho Jin Ryu soon hyung Hong Department of Material Science and Engineering Korea Advanced Institute of Science and Technology(KAIST)291 Daehak-roYuseong-guDaejeon 34141Republic of Korea Department of Nuclear and Quantum Engineering Korea Advanced Institute of Science and Technology(KAIST)291 Daehak-roYuseong-guDaejeon 34141Republic of Korea

Light and strong AlxCrNbVMo(x=0,0.5,and 1.0)refractory high-entropy alloys(RHEAs)were designed and fabricated via a the powder metallurgical *** microstructure of the AlxCrNbVMo alloys consisted of a single BCC crystalline structure with a sub-micron grain size of 2-3μm,and small amounts(<4 vol.%)of fine oxide *** homogeneous microstructure,without chemical segregation or micropores was achieved via high-energy ball milling and spark-plasma *** alloys exhibited superior mechanical properties at 25 and 1000℃compared to those of other ***,CrNbVMo alloy showed a yield strength of 2743 MPa at room ***,the yield strength of the CrNbVMo alloy at 1000℃was 1513 *** specific yield strength of the CrNbVMo alloy was increased by 27%and 87%at 25 and 1000℃,respectively,compared to the AlMo_(0.5) NbTa_(0.5)TiZr RHEA,which exhibited so far the highest specific yield strength among the cast *** addition of Al to CrNbVMo alloy was advantageous in reducing its reduce density to below 8.0 g/cm^(3),while the elastic modulus decreased due to the much lower elastic modulus of Al compared to that of the CrNbVMo *** analysis of the strengthening contributions,showed that the solid solution strengthening,arising from a large misfit effect due to the size and modulus,and the high shear modulus of matrix,was revealed to predominant strengthening mechanism,accounting for over 50%of the yield strength of the AlxCrNbVMo RHEAs.

关键词： High-entropy alloy Powder metallurgy Refractory Strengthening mechanisms Oxide dispersoids

Current management of hepatocellular carcinoma:An Eastern perspective

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World Journal of Gastroenterology 2015年第13期21卷 3826-3842页

作者： hyung Joon Yim Sang Jun Suh soon Ho Um Division of Gastroenterology and Hepatology Department of Internal MedicineKorea University Ansan HospitalAnsan-si 425-707Gyeonggi-doSouth Korea Division of Gastroenterology and Hepatology Department of Internal MedicineKorea University Anam HospitalKorea University College of MedicineSeoul 136-705South Korea

Hepatocellular carcinoma(HCC) is one of the leading causes of cancer death, especially in Eastern areas. With advancements in diagnosis and treatment modalities for HCC, the survival and prognosis of HCC patients are improving. However, treatment patterns are not uniform between areas despite efforts to promote a common protocol. Although many hepatologists in Asian countries may adopt the principles of the Barcelona Clinic Liver Cancer staging system, they are also independently making an effort to expand the indications of each treatment and to combine therapies for better outcomes. Several expanded criteria for liver transplantation in HCC have been developed in Asian countries. Living donor liver transplantation is much more commonly performed in these countries than deceased donor liver transplantation, and it may be preceded by other treatments such as the down-staging of tumors. Local ablation therapies are often combined with transarterial chemoembolization( TACE) and the outcome is comparable to that of surgical resection. The indications of TACE are expanding, and there are new types of transarterial therapies. Although data on drug-eluting beads, TACE, and radioembolization in Asian countries are still relatively sparse compared with Western countries, these methods are gradually gaining popularity because of better tolerability and the possibility of improved response rates. Hepatic arterial infusion chemotherapy and radiotherapy are not included in Western guidelines, but are currently being used actively in several Asian countries. For more advanced HCCs, appropriate combinations of TACE, radiotherapy, and sorafenib can be considered, and emerging data indicate improved outcomes of combination therapies compared with single therapies. To include these paradigm shifts into newer treatment guidelines, more studies may be needed, but they are certainly in progress.

关键词： Hepatocellular carcinoma Eastern Treatment Guideli

In-situ synthesis of TiC/Fe alloy composites with high strength and hardness by reactive sintering

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Journal of Materials Science & Technology 2018年第8期34卷 1397-1404页

作者： Junho Lee Dongju Lee Myung Hoon Song Wonhyuk Rhee Ho Jin Ryu soon hyung Hong Department of Materials Science and Engineering Korea Advanced Institute of Science and Technology291 Daehak-roYuseong-guDaejeon305-701Republic of Korea Department of Nuclear and Quantum Engineering Korea Advanced Institute of Science and Technology291 Daehak-roYuseong-guDaejeon305-701Republic of Korea Nuclear Materials Development Division Korea Atomic Energy Research Institute111 Daedeok-daero 989 Beon-gilYuseong-guDaejeon305-353Republic of Korea Daewha Alloytech Corporation 17-60Sanupdanji-gilMyeoncheon-myeonDangjin-siChungcheongnam-doRepublic of Korea

Fe alloy composites reinforced with in-situ titanium carbide （TIC） particles were fabricated by reactive sintering using different reactant C/Ti ratios of 0.8, 0.9, 1 and 1.1 to investigate the microstructure and mechanical properties ofin-situ TiC/Fe alloy composites. The microstructure showed that the in-situ syn- thesized TiC particles were spherical with a size of 1-3 }~m, irrespective of C/Ti ratio. The stoichiometry of in-situ TiC increased from 0.85 to 0.88 with increasing C/Ti ratio from 0.8 to 0.9, but remained almost unchanged for C/Ti ratios between 0.9 and 1.1 due to the same driving force for carbon diffusion in TiCx at the common sintering temperature. The in-situ TiC/Fe alloy composite with C[Ti ~ 0.9 showed improved mechanical properties compared with other C/Ti ratios because the presence of excess carbon （C/Ti = 1 and 1.1） resulted in unreacted carbon within the Fe alloy matrix, while insufficient carbon （C/Ti = 0.8） caused the depletion of carbon from the Fe alloy matrix, leading to a significant decrease in hardness. This study presents that the maximized hardness and superior strength of in-situ TiC/Fe alloy composites can be achieved by microstructure control and stoichiometric analysis of the in-situ synthesized TiC par- ticles, while maintaining the ductility of the composites, compared to those of the unreinforced Fe alloy. Therefore, we anticipate that the in-situ synthesized TiC/Fe alloy composites with enhanced mechanical properties have great potential in cutting tool, mold and roller material applications.

关键词： Metal matrix composites Sintering Mechanical properties Microstructures

Removal of arsenate and arsenite from aqueous solution by waste cast iron

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Journal of Environmental Sciences 2012年第4期24卷 589-595页

作者： Nag-Choul Choi Song-bae Kim soon-Oh Kim Jae-Won Lee Jun-Boum Park Department of Rural Systems Engineering Seoul National UniversitySeoul 151-921Republic of Korea Department of Earth and Environmental Sciences and Research Institute of Natural Science Gyeongsang National UniversityJinju 660-701Republic of Korea JIU Corporation 154-3 Samsung-dongGangnam-guSeoul 135-879Republic of Korea Department of Civil and Environmental Engineering Seoul National UniversitySeoul 151-742Republic of Korea

The removal of As（III） and As（V） from aqueous solution was investigated using waste cast iron, which is a byproduct of the iron casting process in foundries. Two types of waste cast iron were used in the experiment： grind precipitate dust （GPD） and cast iron shot （CIS）. The X-ray diffraction analysis indicated the presence of Fe~ on GPD and CIS. Batch experiments were performed under different concentrations of As（III） and As（V） and at various initial pH levels. Results showed that waste cast iron was effective in the removal of arsenic. The adsorption isotherm study indicated that the Langmuir isotherm was better than the Freundlich isotherm at describing the experimental result. In the adsorption of both As（III） and As（V）, the adsorption capacity of GPD was greater than CIS, mainly due to the fact that GPD had higher surface area and weight percent of Fe than CIS. Results also indicated the removal of As（III） and As（V） by GPD and CIS was influenced by the initial solution pH, generally decreasing with increasing pH from 3.0 to 10.5. In addition, both GPD and CIS were more effective at the removal of As（III） than As（V） under given experimental conditions. This study demonstrates that waste cast iron has potential as a reactive material to treat wastewater and groundwater containing arsenic.

关键词： waste cast iron arsenic removal sorption batch experiment

Comparison of litterfall production in three forest types in Jeju Island, South Korea

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Journal of Forestry Research 2020年第3期31卷 945-952页

作者： Ji Young An Si Ho Han Woo Bin Youn Sang Ick Lee Afroja Rahman Huong Thi Thuy Dao Jeong Min Seo Aung Aung hyung-soon Choi Hwa Ja Hyun Byung bae Park Department of Natural Resources Kyoto UniversityKyoto 606-8502Japan Department of Environment and Forest Resources Chungnam National UniversityDaejeon 34134Republic of Korea Forest Environment Conservation Division Korea Forest ServiceDaejeon 35208Republic of Korea Forest Conservation Department National Institute of Forest ScienceSeoul 02455Republic of Korea Warm Temperate and Subtropical Forest Research Center National Institute of Forest ScienceSeogwipo 63582Republic of Korea

Litterfall, which is influenced by physical and biological factors, is a major pathway for carbon and nutrient cycling in forest ecosystems. The purpose of this study was to investigate monthly litterfall production in three forests in Jeju Island differentiated by forest composition and precipitation: Cheongsu(Quercus glauca as the dominant species;low precipitation), Seonheulb(Q. glauca as the dominant species;high precipitation), and Seonheulm(Q. glauca and Pinus thunbergii as the dominant species;high precipitation). Litterfall was collected monthly from April to December 2015 and divided into leaf litter, twig, bark, seeds, and unidentified *** patterns of litterfall production varied across stands according to their species composition. However,the amount of leaf litterfall and total litterfall were comparable among stands, ranging from 362 to 375 g m-2 for leaf litter and 524 g m-2 to 580 g m-2 for total *** leaf litter in May was the highest in all stands, while needle litter was the highest in December in *** twig litterfall in July may be attributable to high rainfall with strong winds and storms during the rainy season. Although forest type and climate factor had no influence on litterfall amounts in this study, the pattern of litterfall production was species dependent, suggesting diverse effects on carbon and nutrient cycling in these forests.

关键词： Coniferous forest Evergreen broadleaved forest Gotjawal Leaf litter Precipitation Temperature

Distribution of electric field for carbon nanotube assembly: Simulation (I)

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Transactions of Nonferrous Metals Society of China 2011年第A1期21卷 117-120页

作者： soon-Geun KWON Soo-Hyun KIM Kwang-Ho KIM Myung-Chang KANG hyung-Woo LEE Department of Mechanical Engineering Korea Advanced Institute of Science and Technology (KAIST) Daejeon 305-701 Korea National Core Research Center for Hybrid Materials Solution Pusan National University

The distribution of electric field for the alignment and attachment of carbon nanotubes (CNTs) was simulated. To be attached at the desired place, the aligned and attracted CNTs should be stayed in the desired area called the stable region or the quasi-stable region for an instant where the change of electric field is minimized. Since the conical electrode has the very narrow sized quasi-stable region, few CNTs can be attached. The rectangular electrodes have a wide stable region, so lots of CNTs can be attached. The results indicate that the round electrode which has a proper sized quasi-stable region is more effective for aligning and attaching a single CNT than the conical or rectangular shaped electrodes.

关键词： carbon nanotubes (CNTs) dielectrophoresis (DEP) round shaped electrode simulation

Enhanced Electrical Properties in Carbon Nanotube/Poly （3-hexylthiophene） Nanocomposites Formed Through Non-Covalent Functionalization

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Nano Research 2011年第11期4卷 1129-1135页

作者： Sung Hye Park Sung Hwan Jin Gwang Hoon Jun SeokwoO Jeon soon hyung Hong Department of Material Science and Engineering Korea Advanced Institutc of Science Technol0gy Daejeon 305＇701 Republic of Korea

Poly（3-hexylthiophene）（P3HT） has received much attention as a good candidate to replace inorganic semiconductors for flexible electronics due to its solution-processability. However, the low charge mobility of P3HT is an obstacle to its commercialization. To overcome this problem, we propose a new non-covalent functionalization method for carbon nanotubes （CNTs） for use in CNT/P3HT nanocomposites. By using modified pyrene molecules with hydrophobic long alkyl chains, the non-covalently functionalized CNTs can become well dispersed in hydrophobic solutions and organic semiconductor matrices. Fabrication of organic thin-film transistors （OTFTs） from the non-covalently functionalized CNT/organic semiconductor nanocomposites shows that our non-covalent functionalization method significantly reduces damage to CNTs during functionalization when compared with covalent functionalization by treatment with acids. The OTFTs show 15 times enhancement of field effect mobility （1.5 × 10^-2 cm^2/（V.s）） compared to the mobility of OTFTs made from pure P3HT. This enhancement is achieved by addition of only 0.25 wt% of CNTs to P3HT.

关键词： Carbon nanotubes conjugated polymers nanocomposites organic thin film transistors

Surface engineering of ZnO electrocatalyst by N doping towards electrochemical CO_(2) reduction

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Journal of Energy Chemistry 2024年第1期88卷 71-81,I0002页

作者： Rohini Subhash Kanase Getasew Mulualem Zewdie Maheswari Arunachalam Jyoti Badiger Suzan Abdelfattah Sayed Kwang-soon Ahn Jun-Seok Ha Uk Sim Hyeyoung Shin soon hyung Kang Department of Interdisciplinary Program for Photonic Engineering Chonnam National UniversityGwangju 61186Republic of Korea Graduate School of Energy Science and Technology(GEST) Chungnam National University99 Daehak-roYuseong-guDaejeon 34134Republic of Korea Department of Chemistry Education and Optoelectronic Convergence Research Center Chonnam National UniversityGwangju 61186Republic of Korea Department of Advanced Chemicals and Engineering Chonnam National UniversityGwangju 61186Republic of Korea School of Chemical Engineering Yeungnam UniversityGyeongsan 38541Republic of Korea Department of Energy Engineering Korea Institute of Energy Technology(KENTECH)Naju 58217Republic of Korea

The discovery of efficient,selective,and stable electrocatalysts can be a key point to produce the largescale chemical fuels via electrochemical CO_(2) reduction(ECR).In this study,an earth-abundant and nontoxic ZnO-based electrocatalyst was developed for use in gas-diffusion electrodes(GDE),and the effect of nitrogen(N)doping on the ECR activity of ZnO electrocatalysts was ***,a ZnO nanosheet was prepared via the hydrothermal method,and nitridation was performed at different times to control the N-doping *** an increase in the N-doping content,the morphological properties of the nanosheet changed significantly,namely,the 2D nanosheets transformed into irregularly shaped ***,the ECR performance of Zn O electrocatalysts with different N-doping content was assessed in 1.0 M KHCO_(3) electrolyte using a gas-diffusion electrode-based ECR *** the ECR activity increased after a small amount of N doping,it decreased for higher N doping *** them,the N:ZnO-1 h electrocatalysts showed the best CO selectivity,with a faradaic efficiency(FE_(CO))of 92.7%at-0.73 V *** hydrogen electrode(RHE),which was greater than that of an undoped Zn O electrocatalyst(FE_(CO)of 63.4%at-0.78 V_(RHE)).Also,the N:ZnO-1 h electrocatalyst exhibited outstanding durability for 16 h,with a partial current density of-92.1 mA cm^(-2).This improvement of N:ZnO-1 h electrocatalyst can be explained by density functional theory calculations,demonstrating that this improvement of N:ZnO-1 h electrocatalyst comes from(ⅰ)the optimized active sites lowering the free energy barrier for the rate-determining step(RDS),and(ⅱ)the modification of electronic structure enhancing the electron transfer rate by N doping.

关键词： ZnO N-doped ZnO Gas-diffusion electrode CO Selectivity Electrochemical CO_(2)reduction