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Kwon Gu-Joong Bandi Rajkumar Yang Bong-Suk Park Chan-Woo Han Song-Yi Park Ji-Soo Lee Eun-Ah Kim Nam-Hun Lee Seung-Hwan 《Cellulose (London, England)》2021,28(14):9169-9185
Cellulose - Lignocellulose nanofibrils (LCNFs) were produced from the biomass of Mongolian oak for the first time using deep eutectic solvent pretreatment and mechanical defibrillation. Three... 相似文献
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Yasumasa Nishiwaki Kazunari Masutani Yoshiharu Kimura Chan-Woo Lee 《Journal of polymer science. Part A, Polymer chemistry》2022,60(14):2043-2054
The ABCBA pentablock copolymers (p-d -l -PPS) comprising poly(d -lactide) (PDLA: A), poly(l -lactide) (PLLA: B) and poly(propylene succinate) (PPS: C) were successfully synthesized by two-step ring-opening polymerization (ROP) of d - and l -lactide using a dihydroxy-terminated PPS as a macro-initiator. The pentablock copolymers revealed the high stereocomplex (sc) crystallinity, thermal stability and elastomeric property in their solution-cast films. It was found that the Tg was found to be proportional to the PPS content, whereas the Tm was proportional to their average block length. The thermal resistivity of the copolymer films was found to be as high as 202°C owing to their sc formation. The copolymers also showed improved stereocomplexibility compared to the enantiomeric mixtures of triblock copolymers (PLLA-PPS-PLLA and PDLA-PPS-PDLA) having similar PLLA and PDLA chain lengths. These pentablock copolymers can afford thermoplastic elastomers or flexible plastic materials having a 100% bio-based content, showing high heat-resistive property. 相似文献
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Yasumasa Nishiwaki Kazunari Masutani Yoshiharu Kimura Chan-Woo Lee 《Journal of polymer science. Part A, Polymer chemistry》2020,58(6):860-871
Bis-hydroxyl-terminated poly(1,2-propylene succinate) (PPS-diols) with high molecular weight (10–40 kDa) are prepared by two-step melt polycondensation of succinic acid and 1,2-propanediol with Ti(BuO)4 as the catalyst. By using these PPS-diols as macroinitiators, the ring-opening polymerization of d - and l -lactides is readily conducted to obtain enantiomeric ABA triblock copolymers consisting of poly(l -lactide) and PPS (B) (t-l -PPS) as well as those of poly(d -lactide) and PPS (B) (t-d -PPS) which have higher PPS compositions (20–70 wt%) in addition to high molecular weight (20–80 kD). The Tg, Tm, and ΔHm values of the t-l -PPS copolymers as well as the stereo mixtures of t-l -PPS/t-d -PPS are controlled to linearly decrease with increasing the PPS content. The copolymers also exhibit higher elastomeric properties with increasing the PPS content. The tensile properties of the copolymer films having higher PPS contents (both the single block copolymers and stereo mixtures) are comparable to those of the oil-based thermoplastic elastomers. It is therefore concluded that these block copolymers can afford thermoplastic elastomers or flexible plastic materials having a 100% biobased content. 相似文献
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Taek-Yeol Jung Jae-Eun Ryu Mi-Mi Jang Soh-Yeon Lee Gyu-Rin Jin Chan-Woo Kim Chae-Young Lee Hyelee Kim EungHan Kim Sera Park Seonjeong Lee Cheolju Lee Wankyu Kim TaeSoo Kim Soo-Young Lee Bong-Gun Ju Hyun-Seok Kim 《Experimental & molecular medicine》2020,52(11):1831
N-α-acetyltransferase 20 (Naa20), which is a catalytic subunit of the N-terminal acetyltransferase B (NatB) complex, has recently been reported to be implicated in hepatocellular carcinoma (HCC) progression and autophagy, but the underlying mechanism remains unclear. Here, we report that based on bioinformatic analysis of Gene Expression Omnibus and The Cancer Genome Atlas data sets, Naa20 expression is much higher in HCC tumors than in normal tissues, promoting oncogenic properties in HCC cells. Mechanistically, Naa20 inhibits the activity of AMP-activated protein kinase (AMPK) to promote the mammalian target of rapamycin signaling pathway, which contributes to cell proliferation, as well as autophagy, through its N-terminal acetyltransferase (NAT) activity. We further show that liver kinase B1 (LKB1), a major regulator of AMPK activity, can be N-terminally acetylated by NatB in vitro, but also probably by NatB and/or other members of the NAT family in vivo, which may have a negative effect on AMPK activity through downregulation of LKB1 phosphorylation at S428. Indeed, p-LKB1 (S428) and p-AMPK levels are enhanced in Naa20-deficient cells, as well as in cells expressing the nonacetylated LKB1-MPE mutant; moreover, importantly, LKB1 deficiency reverses the molecular and cellular events driven by Naa20 knockdown. Taken together, our findings suggest that N-terminal acetylation of LKB1 by Naa20 may inhibit the LKB1–AMPK signaling pathway, which contributes to tumorigenesis and autophagy in HCC.Subject terms: Cancer prevention, Tumour biomarkers 相似文献
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Dan Phuong Nguyen Se-Young O Chan-Woo Park Keesam Shin Chan-Gyu Lee Toshitada Shimozaki Takahisa Okino 《Journal of magnetism and magnetic materials》2008,320(14):e264-e267
[Fe(0.5 nm)/Pt(0.5 nm)]40, [Fe(1 nm)/Pt(1.5 nm)]20 and [Fe(3 nm)/Pt(3 nm)]10 multilayer were prepared by DC magnetron sputtering. By conventional furnace annealing (CA) at 270–600 °C for various time, all of the films still remained the disordered structure with the soft magnetic phase. By rapid thermal annealing (RTA) at 500 °C for various time, we obtained the [Fe(1 nm)/Pt(1.5 nm)]20 and [Fe(3 nm)/Pt(3 nm)]10 films with L12 ordered FePt3 phase which was almost ferromagnetic at room temperature. However, the [Fe(0.5 nm)/Pt(0.5 nm)]40 films was still disordered state even under RTA. Compared with CA, RTA exposed an outstanding effect on accelerating the phase transition when the film thickness is over [Fe(0.5 nm)/Pt(0.5 nm)]40. 相似文献
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The electrorheological (ER) properties of poly(2-dodecyloxyaniline) (PDOA) suspensions in silicone oil were investigated. The ER behavior of such suspensions of polyaniline particles depends on the type of stabilizer and doping or dedoping level. Here we report on the ER behavior of particles of a substituted polyaniline with long alkyl pendants. Rheological measurements were carried out using a rotational rheometer with high-voltage generator in both constant shear stress and rate modes. Suspensions of the as-synthesized polyaniline particles in silicone oil showed a substantial ER response. 相似文献
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Park Chan-Woo Kim Tae-Gun Kim Min-Woo Aldalbahi Ali El-Newehy Mohamed Yoon Sam S. 《显形杂志》2020,23(2):269-285
Journal of Visualization - Semiconducting silicon wafers were subjected to centrifugal wet cleaning to remove micro-contaminants. The circular wafers were rotated while a cleaning liquid was... 相似文献