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211.
212.
Yujin Lee Hyo Geun Koo Seung Pyo Jang Alan B. Erdmann Samantha S. Vernetti Cheal Kim 《Supramolecular chemistry》2014,26(3-4):245-250
The synthesis, spectroscopic characterisation, conformational switching and fluorescence quenching efficiency of a resorcinarene-based cavitand containing Zn-salen (Zn-Cav) are reported. Synthesis of Zn-Cav was accomplished by the condensation of a quinoxaline derivatised with Zn-salen and a resorcinarene-based cavitand containing three quinoxalines. 1H NMR spectroscopy confirmed that in DMSO, chloroform and acetone Zn-Cav resides in the vase conformation. The molecular geometry of Zn-Cav selectively changes from vase to kite under acidic conditions. Detection by fluorescence quenching of nitro-containing molecules, such as 4-nitrotoluene, 2,4-dinitrotoluene and 2,3-dimethyl-2,3-dinitrobutane was explored by spectrofluorimetry. It was found that the fluorescence of Zn-Cav is efficiently quenched by nitroaromatic compounds. 相似文献
213.
Young Ki Lee Wonhee Hur Sung Won Lee Sung Woo Hong Sung Woo Kim Jung Eun Choi Seung Kew Yoon 《Experimental & molecular medicine》2014,46(2):e77
14-3-3ζ is related to many cancer survival cellular processes. In a previous study, we showed that silencing 14-3-3ζ decreases the resistance of hepatocellular carcinoma (HCC) to chemotherapy. In this study, we investigated whether silencing 14-3-3ζ affects the radioresistance of cancer stem-like cells (CSCs) in HCC. Knockdown of 14-3-3ζ decreased cell viability and the number of spheres by reducing radioresistance in CSCs after γ-irradiation (IR). Furthermore, the levels of pro-apoptotic proteins were upregulated in CSCs via silencing 14-3-3ζ after IR. These results suggest that 14-3-3ζ knockdown enhances radio-induced apoptosis by reducing radioresistance in liver CSCs. 相似文献
214.
Yeon-Ah Lee Hye-In Ji Sang-Hoon Lee Seung-Jae Hong Hyung-In Yang Myung Chul Yoo Kyoung Soo Kim 《Experimental & molecular medicine》2014,46(1):e72
This study was performed to evaluate the contribution of adiponectin to the production of interleukin (IL)-6, IL-8, vascular endothelial growth factor (VEGF), matrix metalloproteinase (MMP)-1 and MMP-13 in human endothelial cells and osteoblasts in arthritic joints. Cultured human umbilical vascular endothelial cells (HUVECs) and osteoblasts were stimulated with adiponectin (1 or 10 μg ml−1) or IL-1β (0.1 ng ml−1) in the presence or absence of hypoxia for 24 h. The protein expression patterns were examined by analyzing culture supernatants using the enzyme-linked immunosorbent assay (ELISA). Adiponectin significantly stimulated the production of VEGF, MMP-1 and MMP-13 in osteoblasts but not in endothelial cells, whereas it significantly stimulated the production of IL-6 and IL-8 in both endothelial cells and osteoblasts. The increase in VEGF production induced by adiponectin was significantly greater than that induced by IL-1β. The production of IL-6 and IL-8 in adiponectin-stimulated endothelial cells was approximately 10-fold higher than that in IL-1β-stimulated endothelial cells; in osteoblasts, adiponectin-induced IL-6 and IL-8 secretion was approximately twofold higher than that induced by IL-1β. In addition, IL-8 production in endothelial cells was approximately sevenfold higher than in osteoblasts. However, IL-6 levels were similar between the two cell types, suggesting that adiponectin may be involved in the production of IL-8 in endothelial cells, which may have an important role in neutrophil recruitment to arthritic joints. Furthermore, the increases in protein expression induced by adiponectin were differentially regulated by hypoxia. In conclusion, adiponectin has a more important role than does IL-1β in the production of mediators that drive synovitis and joint destruction in endothelial cells and osteoblasts at physiological concentrations. 相似文献
215.
Vinod Mathew Jihyeon Gim Eunjoung Kim Muhammad Hilmy Alfaruqi Jinju Song Docheon Ahn Won Bin Im Younkee Paik Jaekook Kim 《Journal of Solid State Electrochemistry》2014,18(6):1557-1567
In the present study, carbon-coated lithium iron phosphate (LiFePO4/C) is prepared directly by a polyol-assisted pyro-synthesis performed under reaction times of a few seconds in open-air conditions. The polyol solvent, tetraethylene glycol (TTEG), acts as a low-cost fuel to facilitate combustion and the released exothermic energy promotes the nucleation and growth processes of the olivine nanoparticles. In addition, phosphoric acid (used as the phosphorous source) acts as a catalyst to accelerate polyol carbonization. The structure analysis of the as-prepared LiFePO4/C using X-ray, neutron diffraction and 7Li NMR studies suggested the efficacy of the rapid technique to produce highly crystalline phase-pure olivine nanocrystals. The electron microscopy and particle-size distribution studies revealed that the average particle diameters lie below 100 nm and confirmed the presence of a surface carbon layer of 2–3 nm thickness. The thermal and elemental studies indicated that the carbon content in the sample was approximately 5 %. The prepared LiFePO4/C cathode delivered capacities of 162 mA h g-1 at 0.1 °C rates with impressive capacity retention for extended cycling. The polyol-assisted pyro-synthesis, which evades the use of external energy sources, is not only a straightforward, simple and timely approach but also offers opportunities for large-scale LiFePO4/C production. 相似文献
216.
Using Simple Spray Pyrolysis to Prepare Yolk–Shell‐Structured ZnO–Mn3O4 Systems with the Optimum Composition for Superior Electrochemical Properties
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Seung Ho Choi Prof. Yun Chan Kang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(11):3014-3018
A spray‐pyrolysis process is introduced as an effective tool for the preparation of yolk–shell‐structured materials with electrochemical properties suitable for anode materials in Li‐ion batteries (LIBs). Yolk–shell‐structured ZnO–Mn3O4 systems with various molar ratios of the Zn and Mn components are prepared. The yolk–shell‐structured ZnO–Mn3O4 powders with a molar ratio of 1:1 of the Zn and Mn components are shown to have high capacities and good cycling performances. 相似文献
217.
Kari Gabrielse Amit Gangar Dr. Nigam Kumar Dr. Jae Chul Lee Dr. Adrian Fegan Jing Jing Shen Dr. Qing Li Dr. Daniel Vallera Dr. Carston R. Wagner 《Angewandte Chemie (International ed. in English)》2014,53(20):5112-5116
The ability to engineer and re‐program the surfaces of cells would provide an enabling synthetic biological method for the design of cell‐ and tissue‐based therapies. A new cell surface‐engineering strategy is described that uses lipid‐chemically self‐assembled nanorings (lipid‐CSANs) that can be used for the stable and reversible modification of any cell surface with a molecular reporter or targeting ligand. In the presence of a non‐toxic FDA‐approved drug, the nanorings were quickly disassembled and the cell–cell interactions reversed. Similar to T‐cells genetically engineered to express chimeric antigen receptors (CARS), when activated peripheral blood mononuclear cells (PBMCs) were functionalized with the anti‐EpCAM‐lipid‐CSANs, they were shown to selectively kill antigen‐positive cancer cells. Taken together, these results demonstrate that lipid‐CSANs have the potential to be a rapid, stable, and general method for the reversible engineering of cell surfaces and cell–cell interactions. 相似文献
218.
Jun Myung Kim So Hyeong Sohn Noh Soo Han Prof. Seung Min Park Prof. Joohoon Kim Prof. Jae Kyu Song 《Chemphyschem》2014,15(14):2917-2921
Direct evidence for the blue luminescence of gold nanoclusters encapsulated inside hydroxyl‐terminated polyamidoamine (PAMAM) dendrimers was provided by spectroscopic studies as well as by theoretical calculations. Steady‐state and time‐resolved spectroscopic studies showed that the luminescence of the gold nanoclusters consisted largely of two electronic transitions. Theoretical calculations indicate that the two transitions are attributed to the different sizes of the gold nanoclusters (Au8 and Au13). The luminescence of the gold nanoclusters was clearly distinguished from that of the dendrimers. 相似文献
219.
Xiayi Hu Enzo Mangano Daniel Friedrich Hyungwoong Ahn Stefano Brandani 《Adsorption》2014,20(1):121-135
A systematic study of the diffusion mechanism of CO2 in commercial 13X zeolite beads is presented. In order to gain a complete understanding of the diffusion process of CO2, kinetic measurements with a zero length column (ZLC) system and a volumetric apparatus have been carried out. The ZLC experiments were carried out on a single bead of zeolite 13X at 38 °C at a partial pressure of CO2 of 0.1 bar, conditions representative of post-combustion capture. Experiments with different carrier gases clearly show that the diffusion process is controlled by the transport inside the macropores. Volumetric measurements using a Quantachrome Autosorb system were carried out at different concentrations. These experiments are without a carrier gas and the low pressure measurements show clearly Knudsen diffusion control in both the uptake cell and the bead macropores. At increasing CO2 concentrations the transport mechanism shifts from Knudsen diffusion in the macropores to a completely heat limited process. Both sets of experiments are consistent with independent measurements of bead void fraction and tortuosity and confirm that under the range of conditions that are typical of a carbon capture process the system is controlled by macropore diffusion mechanisms. 相似文献
220.
Soumen Dutta Nitee Kumari Sateesh Dubbu Sun Woo Jang Amit Kumar Hiroyoshi Ohtsu Junghoon Kim Seung Hwan Cho Masaki Kawano In Su Lee 《Angewandte Chemie (International ed. in English)》2020,59(9):3416-3422
Rational engineering and assimilation of diverse chemo‐ and biocatalytic functionalities in a single nanostructure is highly desired for efficient multistep chemical reactions but has so far remained elusive. Here, we design and synthesize multimodal catalytic nanoreactors (MCNRs) based on a mesoporous metal‐organic framework (MOF). The MCNRs consist of customizable metal nanocrystals and stably anchored enzymes in the mesopores, as well as coordinatively unsaturated cationic metal MOF nodes, all within a single nanoreactor space. The highly intimate and diverse catalytic mesoporous microenvironments and facile accessibility to the active site in the MCNR enables the cooperative and synergistic participation from different chemo‐ and biocatalytic components. This was shown by one‐pot multistep cascade reactions involving a heterogeneous catalytic nitroaldol reaction followed by a [Pd/lipase]‐catalyzed chemoenzymatic dynamic kinetic resolution to yield optically pure (>99 % ee) nitroalcohol derivatives in quantitative yields. 相似文献