Effect of Aluminum on Thermally Induced ε-Martensite for Fe-Mn-C TWIP Steels

Myungjin Lee,박철호,Eun-Joon Chun,Juseung Lee,강남현 대한용접접합학회 2019 대한용접·접합학회지 Vol.37 No.1

Cold-rolling of hot-rolled plate of Fe-18.7Mn-0.61C-1.4Al (Al-TWIP) steel was identified with an austenite single phase through the entire thickness, and that of Fe-17.8Mn-0.57C (TWIP) steel was composed of ε-martensite and austenite phases from the surface to a thickness of ~45 ㎛. Electron back-scattered diffraction (EBSD), glow discharge spectrometry (GDS), and transmission electron microscopy (TEM) were conducted to investigate the ε-martensite transformation of TWIP steel. In TWIP steel, thermally induced ε-martensite transformation was produced since the surface austenite stability decreased due to surface decarburization. The thickness of ε-martensite (~45 ㎛) was coincident with the depth at which 0.45 wt% C of TWIP steel was achieved. However, the TWIP steel with added Al increased the austenite stability of the surface layer and suppressed ε-martensite transformation.

Noise Reduction for Photon Counting Imaging Using Discrete Wavelet Transform

Lee, Jaehoon,Kurosaki, Masayuki,Cho, Myungjin,Lee, Min-Chul The Korea Institute of Information and Commucation 2021 Journal of information and communication convergen Vol.19 No.4

In this paper, we propose an effective noise reduction method for photon counting imaging using a discrete wavelet transform. Conventional 2D photon counting imaging was used to visualize the object under dark conditions using statistical methods, such as the Poisson random process. The photons in the scene were estimated using a statistical method. However, photons which disturb the visualization and decrease the image quality may occur in the background where there is no object. Although median filters are used to reduce the noise, the noise in the scene remains. To remove the noise effectively, our proposed method uses the discrete wavelet transform, which removes the noise in the scene using a specific thresholding method that utilizes photon counting imaging characteristics. We conducted an optical experiment to demonstrate the denoising performance of the proposed method.

Effect of the synthesized mycolic acid on the biodegradation of diesel oil by <i>Gordonia nitida</i> strain LE31

Lee, Myungjin,Kim, Myung Kyum,Kwon, Mi-Jung,Park, Byeong Deog,Kim, Moo Hoon,Goodfellow, Michael,Lee, Sung-Taik Elsevier 2005 Journal of bioscience and bioengineering Vol.100 No.4

<P>The dynamics of diesel oil biodegradation were previously investigated at initial substrate concentrations of 1000 to 20,000 ppm using <I>Gordonia nitida</I> isolated from wastewater. Following the gas chromatogram profiles of diesel oil degradation, diesel oil with concentrations of up to 15,000 ppm was efficiently degraded by this strain. At a concentrations of 20,000 ppm, however, the degradation by this strain was not effective. The enhancement of the biodegradation of diesel oi1 (at 15,000 and 20,000 ppm) by a synthetic mycolic acid biosurfactant (at 9, 90 and 900 ppm) was also investigated. In <I>G. nitida</I> inoculated cultures, the degradation of diesel oil was enhanced by the biosurfactant. For comparison, diesel oil degradation in batch incubations was measured after the addition of rhamnolipid and other surfactants. Synthetic mycolic acid enhanced the degradation to a greater extent than any other surfactant tested. Additionally, it was demonstrated that the degradation-enhancing property of synthetic mycolic acid was similar to that of rhamnolipid and Tween 80.</P>

Inter-row Adsorption Configuration and Stability of Threonine Adsorbed on the Ge(100) Surfaces

Myungjin Lee,박영찬,정혁,이한길 대한화학회 2013 Bulletin of the Korean Chemical Society Vol.34 No.4

The adsorption structures of threonine on the Ge(100) surface were investigated using core-level photoemission spectroscopy (CLPES) in conjunction with density functional theory (DFT) calculations. CLPES measurements were performed to identify the experimentally preferred adsorption structure. The preferred structure indicated the relative reactivities of the carboxyl and hydroxymethyl groups as electron donors to the Ge(100) surface during adsorption. The core-level C 1s, N 1s, and O 1s CLPES spectra indicated that the carboxyl oxygen competed more strongly with the hydroxymethyl oxygen during the adsorption reaction. Three among six possible adsorption structures were identified as energetically favorable using DFT calculation methods that considered the inter- and intra-bonding configurations upon adsorption onto the Ge(100) surface. These structures were O-H dissociated N dative inter bonding, O-H dissociated N dative intra bonding, O-H dissociation bonding. One of the adsorption structures: O-H dissociated N dative inter bonding was predicted to be stable in light of the transition state energies. We thus confirmed that the most favorable adsorption structure is the O-H dissociated N dative-inter bonding structure using CLPES and DFT calculation.

Nickel Electroplated Microfluidic Bio-MEMS Chip for Tumor Marker Detection using Magnetic Particle Separation

Myungjin Chung(정명진),Min-hye Oh(오민혜),Jin-Kyoung Yang(양진경),Yongseung Lee(이용승),Yong-Kweon Kim(김용권),Yoon-Sik Lee(이윤식) 대한전기학회 2016 대한전기학회 학술대회 논문집 Vol.2016 No.10

Inflammation-Modulated Metabolic Reprogramming Is Required for DUOX-Dependent Gut Immunity in <i>Drosophila</i>

Lee, Kyung-Ah,Cho, Kyu-Chan,Kim, Boram,Jang, In-Hwan,Nam, Kibum,Kwon, Young Eun,Kim, Myungjin,Hyeon, Do Young,Hwang, Daehee,Seol, Jae-Hong,Lee, Won-Jae Elsevier 2018 Cell host & microbe Vol.23 No.3

<P><B>Summary</B></P> <P>DUOX, a member of the NADPH oxidase family, acts as the first line of defense against enteric pathogens by producing microbicidal reactive oxygen species. DUOX is activated upon enteric infection, but the mechanisms regulating DUOX activity remain incompletely understood. Using <I>Drosophila</I> genetic tools, we show that enteric infection results in “pro-catabolic” signaling that initiates metabolic reprogramming of enterocytes toward lipid catabolism, which ultimately governs DUOX homeostasis. Infection induces signaling cascades involving TRAF3 and kinases AMPK and WTS, which regulate TOR kinase to control the balance of lipogenesis versus lipolysis. Enhancing lipogenesis blocks DUOX activity, whereas stimulating lipolysis via ATG1-dependent lipophagy is required for DUOX activation. <I>Drosophila</I> with altered activity in TRAF3-AMPK/WTS-ATG1 pathway components exhibit abolished infection-induced lipolysis, reduced DUOX activation, and enhanced susceptibility to enteric infection. Thus, this work uncovers signaling cascades governing inflammation-induced metabolic reprogramming and provides insight into the pathophysiology of immune-metabolic interactions in the microbe-laden gut epithelia.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Enteric infection stimulates pro-catabolic signaling in the gut epithelia </LI> <LI> Infection induces metabolic reprogramming of gut epithelia toward lipid catabolism </LI> <LI> Gut metabolic reprogramming is required for DUOX activity and resistance to infection </LI> </UL> </P> <P><B>Graphical Abstract</B></P> <P>[DISPLAY OMISSION]</P>

New Taxa in Alphaproteobacteria: Brevundimonas olei sp. nov., an Esterase-Producing Bacterium

Myungjin Lee,Sathiyaraj Srinivasan,김명겸 한국미생물학회 2010 The journal of microbiology Vol.48 No.5

A polyphasic taxonomic approach was used to characterize a Gram-negative, non-motile bacterium, designated MJ15T, that was isolated from soil of a GS-Caltex Oil reservoir in Korea. As shown by comparative 16S rRNA gene sequence analysis, strain MJ15T belongs to genus Brevundimonas. The 16S rRNA gene sequence similarities ranged from 95.6-99.2% between strain MJ15T and validated representatives of the genus Brevundimonas. With respect to Brevundimonas species, strain MJ15T exhibited DNA-DNA relatedness values below 40.7%. The G+C content of the genomic DNA was 61.7 mol%. Strain MJ15T contained ubiquinone Q-10. The major fatty acids were C16:0 (27.7%), C19:0 cyclo ω8c (23.2%), summed feature 8 (containing C18:1 ω7c/C18:1 ω6c) (28.5%), and major hydroxyl fatty acid was C12:0 3OH (3.7%). Based upon its phenotypic and genotypic properties, as well as its phylogenetic distinctiveness, strain MJ15T (KCTC 22461T; JCM 16237T) should be classified in the genus Brevundimonas as the type strain of a novel species. The name Brevundimonas olei sp. nov. is proposed for this new species.

Molecular characterization of Arabidopsis thaliana LSH1 and LSH2 genes

Myungjin Lee,Xiangshu Dong,Hayong Song,Ju Yeon Yang,Soyun Kim,YoonkangHur 한국유전학회 2020 Genes & Genomics Vol.42 No.10

Background Arabidopsis thaliana genome encodes ten DUF640 (short for domain of unknown function 640)/ALOG (short for Arabidopsis LSH1 and Oryza G1) proteins, also known as light-dependent short hypocotyl (LSH) proteins. While some of the LSH genes regulate organ boundary determination and shade avoidance response, the function of most of these genes remains largely unknown. Objective In this study, we aimed to characterize the function of AtLSH1 and AtLSH2 in Arabidopsis. Methods We overexpressed AtLSH1 and AtLSH2 (with or without the FLAG tag) in Arabidopsis Col-0 plants under the control of the 35S promoter. We also generated knockout or knockdown lines of these genes by miRNA-induced gene silencing (MIGS). We conducted intensive phenotypic analysis of these transgenic lines, and fnally performed RNA-seq analysis of two AtLSH2 overexpression (OX) lines. Results Although AtLSH1 and AtLSH2 amino acid sequences showed high similarly, AtLSH2-OX lines showed much higher levels of their transcripts than those of AtLSH1-OX lines. Additionally, overexpression of AtLSH1 and AtLSH2 greatly inhibited hypocotyl elongation in a light-independent manner, and reduced both vegetative and reproductive growth. However, knockout or knockdown of both these AtLSH genes did not afect plant phenotype. Gene Ontology (GO) analysis of diferentially expressed genes (DEGs) identifed by RNA-seq revealed enrichment of the GO term ‘response to stimulus’, included phytohormone-responsive genes; however, genes responsible for the abnormal phenotypes of AtLSH2-OX lines could not be identifed. Conclusion Although our data revealed no close association between light and phytohormone signaling components, overexpression of AtLSH1 and AtLSH2 greatly reduced vegetative and reproductive growth of Arabidopsis plants. This property could be used to generate new plants by regulating expression of AtLSH1 and AtLSH2.

Inter-row Adsorption Configuration and Stability of Threonine Adsorbed on the Ge(100) Surfaces

Lee, Myungjin,Park, Youngchan,Jeong, Hyuk,Lee, Hangil Korean Chemical Society 2013 Bulletin of the Korean Chemical Society Vol.34 No.4

The adsorption structures of threonine on the Ge(100) surface were investigated using core-level photoemission spectroscopy (CLPES) in conjunction with density functional theory (DFT) calculations. CLPES measurements were performed to identify the experimentally preferred adsorption structure. The preferred structure indicated the relative reactivities of the carboxyl and hydroxymethyl groups as electron donors to the Ge(100) surface during adsorption. The core-level C 1s, N 1s, and O 1s CLPES spectra indicated that the carboxyl oxygen competed more strongly with the hydroxymethyl oxygen during the adsorption reaction. Three among six possible adsorption structures were identified as energetically favorable using DFT calculation methods that considered the inter- and intra-bonding configurations upon adsorption onto the Ge(100) surface. These structures were O-H dissociated N dative inter bonding, O-H dissociated N dative intra bonding, O-H dissociation bonding. One of the adsorption structures: O-H dissociated N dative inter bonding was predicted to be stable in light of the transition state energies. We thus confirmed that the most favorable adsorption structure is the O-H dissociated N dative-inter bonding structure using CLPES and DFT calculation.

Bench-scale ex situ diesel removal process using a biobarrier and surfactant flushing

Myungjin Lee,이영철,우성근,Eun-Sil Choi,안영희,박준홍,양지원 한국공업화학회 2012 Journal of Industrial and Engineering Chemistry Vol.18 No.3

Ex situ diesel removal was demonstrated using a biobarrier with immobilized cells and surfactant flushing in a bench-scale system. Four strains (two Acinetobacter sp., one Gordonia sp., and one Rhodococcus sp.) isolated from a diesel-contaminated site were immobilized onto a matrix to act as a biofiller. Peat moss, bentonite, and alginate were used as a hybrid support, and a procedure for the use of a bench-scale biobarrier was also employed. According to a microbial counting assay used for the biobarrier, the total amount of bacterial cells increased from approximately 2 109 to 8 109 (colony forming unit (CFU)/g) and the amount of inoculated diesel-degrading bacteria slightly increased from 2 106 to 5 106 (CFU/g) in the same period (over 30 days). This increase resulted in the reduction of diesel from 6000 45 mg/kg to below 5 mg/kg. While 99.9%, i.e. up to below 5 mg/L of the diesel in soil was treated during 30 days of operation, diesel biodegradation accounted for 24.3% of the reduction of diesel.