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701.
702.
A series of imidazole-containing rod-like Schiff's bases and their ionic copper(II) chelates with various lengths of the terminal alkyl chain containing 6, 8, 10, 12, 14 and 16 carbon atoms have been synthesised. The synthesised compounds were characterised by elemental analyses, 1H NMR, IR and UV–vis and mass spectroscopies. Thermotropic smectic C mesophases in the ligands and smectic A mesophases in the copper(II) complexes were identified using POM, DSC and small-angle XRD scattering methods. X-ray diffraction patterns of the prepared imidazole imines indicate to supramolecular self-assembled structures in the liquid crystal state, which are formed by means of intermolecular hydrogen bonds. It was established that both liquid crystal arrangement and supramolecular assemblies in ligands disappeared near 190°C, mainly regardless of the lengths of the terminal alkyl chains. Contrary, assembling of the copper(II) complexes into supramolecular bilayers occurs near 200°C, which causes their transition to a smectic A mesophase. 相似文献
703.
Chung Il Lee Sung Yeon Hwang Eui Sang YooSeung Soon Im 《Polymer Degradation and Stability》2011,96(2):190-196
A series of biodegradable poly(oxyethylene-b-butylene adipate) ionomers (POBAi) were prepared by two-step in situ polymerization using adipic acid, 1,4-butanediol and mixed monomers of bis(poly(oxyethylene)) sulfonated dimethyl fumarate. The chemical composition of these POBAi was ascertained by 1H NMR spectroscopy. The objective of this study was to investigate the shape memory effect of POBAi containing ionomer compared to non ionic POBA. It was observed that POBA5.0i showed a good shape memory effect than that of POBA 2.5 mol% or none of ionic group due to much physical cross-linking point by rich ionic group. Stress-induced phase transition was investigated during the shape deformation and recovery process using a wide-angle X-ray diffractometer (WAXD). The POBA crystal phase transition from β- to α-form was observed in all POBA samples by either thermal treatment or physical drawing. The α-form crystal did not recover to the initial β-form during the recovery process because the monoclinic α-form crystal is structurally more stable than the orthorhombic β-form crystal. 相似文献
704.
Lee CY Bae YS Jeong NC Farha OK Sarjeant AA Stern CL Nickias P Snurr RQ Hupp JT Nguyen ST 《Journal of the American Chemical Society》2011,133(14):5228-5231
A series of isostructural, noncatenated, zinc-pillared-paddlewheel metal-organic framework materials has been synthesized from 1,2,4,5-tetrakis(carboxyphenyl)benzene and trans-1,2-dipyridylethene struts. Substantial kinetic selectivity in the adsorption of propene over propane can be observed, depending on the pore apertures and the rectangular-plate morphology of the crystals. 相似文献
705.
706.
The interest in utilizing food-derived compounds therapeutically has been rising. With the growing prevalence of systematic chronic inflammation (SCI), efforts to find treatments that do not result in the side effects of current anti-inflammatory drugs are underway. Bioactive peptides (BAPs) are a particularly promising class of compounds for the treatment of SCI, and the abundance of high-quality seafood processing byproducts (SPB) makes it a favorable material to derive anti-inflammatory BAPs. Recent research into the structural properties of anti-inflammatory BAPs has found a few key tendencies including they tend to be short and of low molecular weight (LMW), have an overall positive charge, contain hydrophobic amino acids (AAs), and be rich in radical scavenging AAs. SPB-derived anti-inflammatory BAPs have been observed to work via inhibition of the NF-κB and MAPK pathways by disrupting the phosphorylation of IκBα and one or more kinases (ERK, JNK, and p38), respectively. Radical scavenging capacity has also been shown to play a significant role in the efficacy of SPB-derived anti-inflammatory BAPs. To determine if SPB-derived BAPs can serve as an effective treatment for SCI it will be important to understand their properties and mechanisms of action, and this review highlights such findings in recent research. 相似文献
707.
Hyun Lee Dong-Min Yu Myeong-Suk Bahn Young-Jae Kwon Min Jee Um Seo Yeon Yoon Ki-Tae Kim Myoung-Woo Lee Sung-Je Jo Sungsoo Lee Seung-Hoi Koo Ki Hoon Jung Jae-Seon Lee Young-Gyu Ko 《Experimental & molecular medicine》2022,54(8):1277
Prominin-1 (PROM1), also known as CD133, is expressed in hepatic progenitor cells (HPCs) and cholangiocytes of the fibrotic liver. In this study, we show that PROM1 is upregulated in the plasma membrane of fibrotic hepatocytes. Hepatocellular expression of PROM1 was also demonstrated in mice (Prom1CreER; R26TdTom) in which cells expressed TdTom under control of the Prom1 promoter. To understand the role of hepatocellular PROM1 in liver fibrosis, global and liver-specific Prom1-deficient mice were analyzed after bile duct ligation (BDL). BDL-induced liver fibrosis was aggravated with increased phosphorylation of SMAD2/3 and decreased levels of SMAD7 by global or liver-specific Prom1 deficiency but not by cholangiocyte-specific Prom1 deficiency. Indeed, PROM1 prevented SMURF2-induced SMAD7 ubiquitination and degradation by interfering with the molecular association of SMAD7 with SMURF2. We also demonstrated that hepatocyte-specific overexpression of SMAD7 ameliorated BDL-induced liver fibrosis in liver-specific Prom1-deficient mice. Thus, we conclude that PROM1 is necessary for the negative regulation of TGFβ signaling during liver fibrosis.Subject terms: Cell signalling, Apoptosis, Post-translational modifications, Mechanisms of disease 相似文献
708.
Park IS Kwon MS Kim N Lee JS Kang KY Park J 《Chemical communications (Cambridge, England)》2005,(45):5667-5669
A new recyclable rhodium catalyst was synthesized by a simple procedure from readily available reagents, which showed high activities in the hydrogenation of various arenes under 1 atm H2 at room temperature. 相似文献
709.
Seo Y Cho CY Hwangbo M Choi HJ Hong SM 《Langmuir : the ACS journal of surfaces and colloids》2008,24(6):2381-2386
Monolayers of a polystyrene-poly(methyl methacrylate) (PS-PMMA) diblock copolymer at the air-water interface were studied by measuring the surface pressure-area isotherms at several temperatures. Langmuir film balance experiments and atomic force microscopy showed that the diblock copolymer molecules formed surface micelles. In the plot of the surface pressure versus surface area per repeating unit, the monolayer changed from the gas phase to the liquid expanded phase at lower surface pressure for systems at low temperature compared to those at high temperature. In addition, a plateau, corresponding to the transition from the liquid expanded to liquid condensed phase, appeared in that plot at lower surface pressure for systems with a higher subphase (water) temperature. Hysteresis was observed in the compression-expansion cycle process. Increasing the subphase temperature alleviated this hyteresis gap, especially at low surface pressures. The minimum in the plot of the surface pressure versus surface area per repeating unit in the expansion process (which arises from the transition) and the transition plateau appeared more vividly at higher water temperature. These dynamic experimental results show that PS-PMMA diblock copolymers, in which both blocks are insoluble in water, do not form complicated entanglements in two-dimensional space. Although higher water temperature provided more entropy to the chains, and thus more conformational freedom, it did not change the surface morphology of the condensed film because both blocks of PS-PMMA are insoluble in water. 相似文献
710.
Novel Hoveyda-type Ru-carbene complexes 7a,b and 8a,b tethering imidazolium tags at chelating isopropoxy group have been synthesized, and investigated their catalytic activities and recyclabilities in ring-closing metathesis (RCM) and cross metathesis (CM) in ionic liquids. They showed excellent catalytic activities for RCM of various dienes in [bmim][PF6]/CH2Cl2 (1/1, v/v). The recyclability of these catalysts is largely dependent on the tether length and the structures of imidazolium tag and ionic liquid, as well as the composition of the ionic solvent system. A combination of the 2-methylated imidazolium ion-tagged Ru-complex 7b with a mixture of [bdmim][PF6]/toluene (1/3, v/v) allowed several times recycling without significant loss of catalytic activity in RCM, however low recyclabilities were observed in CMs. 相似文献