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841.
Ki-Young Choi Moon-Won Kim Ji-Wook Ryu Suk Nam Choi Byung Bin Park Mancheol Suh Il-Hwan Suh 《Journal of chemical crystallography》2001,31(2):81-86
The compound [Ni(L)(2-NO2)]ClO4 (L = 5,5,7,12,12,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane) has been synthesized and structurally characterized. It crystallizes in the monoclinic system, space group P21/c with a = 26.899(5), b = 8.476(2), c = 23.633(5) Å, = 115.12(13)°, V = 4878.6(17) Å3, and Z = 4. Each nickel(II) ion has a six-coordinated bicapped square-pyramidal geometry with four secondary amines of the macrocycle and two oxygen atoms of the bidentate nitrito group. Electronic spectra and effective magnetic moment of the complex also exhibit a high-spin six-coordinated geometry. 相似文献
842.
Jong Seung Kim Won Ku Lee Soo Heon Lee Jin-Gyu Kim Il-Hwan Suh Jong Yeol Kim Jong Wan Kim 《Journal of inclusion phenomena and macrocyclic chemistry》2001,40(3):183-187
An unsymmetrical calix[4]-bis-crown ether having both conventional crown-6 and dibenzocrown-6 rings in a fixed 1,3-alternate conformation was synthesized with good yield by the reaction of a monocyclic calix[4]crown-6 with dibenzodimesylate in the presence of cesium carbonate. The cesium ion selectivity among alkali metal ions increased compared to symmetrical calix[4]-bis-crown-6. The solid state structureof the ligand-cesium complex illustrates a 1:2 complex ratio. On the contrary, insolution, e.g., extraction equilibrium and 1H NMR experiment gave a 1:1 complex ratio. From the result of the chemical shift change upon metal ion complex, the cesium ion seems to prefer the dibenzocrown loop to the conventional crown-6 ring. 相似文献
843.
Summary Zirconia is known to be one of the best materials for the chromatographic support due to its excellent chemical, thermal and
mechanical stability. In this work we report preparation and use of bovine serum albumin (BSA)-immobilized zirconia as a chiral
stationary phase for separation of some enantiomers in reversed-phase liquid chromatography. The BSA-zirconia showed good
enantioselectivity for some of the enantiomers studied and could be used for RPLC separations in mobile phases of alkaline
pH. 相似文献
844.
Seung Eun Jung Sang Woo Kim Seongtae Jeong Hanbyeol Moon Won Seok Choi Soyeon Lim Seahyoung Lee Ki-Chul Hwang Jung-Won Choi 《Experimental & molecular medicine》2021,53(9):1332
Myocardial infarction (MI) damage induces various types of cell death, and persistent ischemia causes cardiac contractile decline. An effective therapeutic strategy is needed to reduce myocardial cell death and induce cardiac recovery. Therefore, studies on molecular and genetic biomarkers of MI, such as microRNAs (miRs), have recently been increasing and attracting attention due to the ideal characteristics of miRs. The aim of the present study was to discover novel causative factors of MI using multiomics-based functional experiments. Through proteomic, MALDI-TOF-MS, RNA sequencing, and network analyses of myocardial infarcted rat hearts and in vitro functional analyses of myocardial cells, we found that cytochrome c oxidase subunit 5a (Cox5a) expression is noticeably decreased in myocardial infarcted rat hearts and myocardial cells under hypoxic conditions, regulates other identified proteins and is closely related to hypoxia-induced cell death. Moreover, using in silico and in vitro analyses, we found that miR-26a-5p and miR-26b-5p (miR-26a/b-5p) may directly modulate Cox5a, which regulates hypoxia-related cell death. The results of this study elucidate the direct molecular mechanisms linking miR-26a/b-5p and Cox5a in cell death induced by oxygen tension, which may contribute to the identification of new therapeutic targets to modulate cardiac function under physiological and pathological conditions.Subject terms: Protein-protein interaction networks, Predictive markers 相似文献
845.
Sungjin Park Seung Woong Yoon Kyung‐Bok Lee Dong Jin Kim Young Hwan Jung Youngkyu Do Hyun‐jong Paik Insung S. Choi 《Macromolecular rapid communications》2006,27(1):47-50
Summary: We report a simple method for tuning catalytic property of a metallocene‐based catalyst, Cp2ZrCl2, for ethylene polymerization by the direct adsorption of Cp2ZrCl2 onto multi‐walled carbon nanotubes (MWCNTs). The direct interactions between MWCNTs and the Cp rings of Cp2ZrCl2 controlled the polymerization behaviors, and we could generate polyethylene with an extremely high molecular weight ( = 1 000 000) at 30 °C and under 1 atm of ethylene gas.
846.
Jee‐Hyun Ryu Jung‐Hun Lee Seung‐Jin Han Kyung‐Do Suh 《Macromolecular rapid communications》2006,27(14):1156-1161
Summary: In order to achieve a reasonable response time in an electrochromic display, viologen‐modified porous polymeric microspheres of various porosities have been used as substrates. Porous microspheres are prepared using seeded polymerization in the presence of a porogen. Based on ionic conductivity and the chronocoulometry measurements, it is confirmed that the electrolyte content increases, and the resistance of the polymer particles in the device decreases as the specific surface area of the porous particles increases. This results in a rapid response time of 270 ms.
847.
In this work, the electric charging effect on the spreading of droplet impacting on dielectric substrates has been investigated. The charged water droplets were directed on the paraffin wax and the Teflon-coated plates. The impinging behavior was visualized and recorded using a CCD camera to identify the maximum extent of the flattened droplets. Droplet diameter and velocity approaching the wall were measured as well. The diameter of the electrically charged droplet at the maximum spread turned out to be larger compared to that of neutral droplet (at the maximum spread), and the difference becomes larger with increasing of the electric charge ratio (defined as the ratio of the actual electric charge to the Rayleigh limit). This phenomenon is considered to be due to reduction of effective interfacial tensions between the liquid and the gas and between the liquid and the solid by electric charging. Finally, an improved model was proposed to predict the maximum spreading ratio for electrically charged droplets by introducing correlations on the liquid–gas and the liquid–solid interfacial tensions. 相似文献
848.
Richard A. Bartsch Leah P. Bitalac Charles L. Cowey Sadik Elshani Mi‐Ja Goo Vincent J. Huber Sheryl N. Ivy Youngchan Jang Russell J. Johnson Jong Seung Kim Elzbieta Luboch Joseph A. Mcdonough Michael J. Pugia Byungki Son Qiang Zhao 《Journal of heterocyclic chemistry》2000,37(5):1337-1350
Synthetic routes to forty‐four dibenzocrown ether alcohols are reported. The new crown ether com pounds are based on a sym‐dibenzo‐16‐crown‐5 platform. Most have a hydroxy group and an alkyl, aryl, aralkyl, alkenyl, alkynyl, or perfluoroalkyl group on the central carbon of the three‐carbon bridge. Others have substituted benzene rings and either a hydroxy or ‐O(CH2)nOH group attached to the central carbon of the three‐carbon bridge. 相似文献
849.
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
850.
Sun-Hwa Ryu Myung-Kil Cho Myungkil Kim Sang-Min Jung Jin-Ho Seo 《Applied biochemistry and biotechnology》2013,171(6):1525-1534
The laccase gene of Polyporus brumalis was genetically transformed to overexpress its laccase. The transformants exhibited increased laccase activity and effective decolorization of the dye Remazol Brilliant Blue R than the wild type. When the transformants were pretreated with wood chips from a red pine (softwood) and a tulip tree (hardwood) for 15 and 45 days, they showed higher lignin-degradation activity as well as higher wood-chip weight loss than the wild type. When the wood chips treated with the transformant were enzymatically saccharified, the highest sugar yields were found to be 32.5 % for the red pine wood and 29.5 % for the tulip tree wood, on the basis of the dried wood weights, which were 1.6-folds higher than those for the wild type. These results suggested that overexpression of the laccase gene from P. brumalis significantly contributed to the pretreatment of lignocellulose for increasing sugar yields. 相似文献