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121.
Won Se Suh Ki Hyun Kim Ho Kyung Kim Sang Un Choi Kang Ro Lee 《Helvetica chimica acta》2015,98(8):1087-1094
Two new aryl‐tetralin lignan glycosides, linderanosides A and B ( 1 and 2 , resp.), and a new dihydrobenzofuran neolignan glycoside, linderanoside C ( 3 ), together with five known lignan derivatives ( 4 – 8 ) were isolated from the trunk of Lindera glauca. The structures of these new compounds were determined through spectroscopic analyses, including extensive 2D‐NMR data and acid hydrolysis. The absolute configurations of the compounds were clarified by circular dichroism (CD) spectroscopic studies. Compounds 1 – 8 were evaluated for their cytotoxicity against A549 (non‐small cell lung adenocarcinoma), SK‐OV‐3 (ovarian cancer cells), A498 (human kidney epithelial cells), and HCT‐15 (colon cancer cells) human tumor cell lines using sulforhodamine B assays in vitro. 相似文献
122.
Surface and Structural Investigation of a MnOx Birnessite‐Type Water Oxidation Catalyst Formed under Photocatalytic Conditions
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Benjamin J. Deibert Jingming Zhang Paul F. Smith Dr. Karena W. Chapman Dr. Sylvie Rangan Debasis Banerjee Kui Tan Hao Wang Nicholas Pasquale Prof. Feng Chen Prof. Ki‐Bum Lee Prof. G. Charles Dismukes Prof. Yves J. Chabal Prof. Jing Li 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(40):14218-14228
Catalytically active MnOx species have been reported to form in situ from various Mn‐complexes during electrocatalytic and solution‐based water oxidation when employing cerium(IV) ammonium ammonium nitrate (CAN) oxidant as a sacrificial reagent. The full structural characterization of these oxides may be complicated by the presence of support material and lack of a pure bulk phase. For the first time, we show that highly active MnOx catalysts form without supports in situ under photocatalytic conditions. Our most active 4MnOx catalyst (~0.84 mmol O2 mol Mn?1 s?1) forms from a Mn4O4 bearing a metal–organic framework. 4MnOx is characterized by pair distribution function analysis (PDF), Raman spectroscopy, and HR‐TEM as a disordered, layered Mn‐oxide with high surface area (216 m2g?1) and small regions of crystallinity and layer flexibility. In contrast, the SMnOx formed from Mn2+ salt gives an amorphous species of lower surface area (80 m2g?1) and lower activity (~0.15 mmol O2 mol Mn?1 s?1). We compare these catalysts to crystalline hexagonal birnessite, which activates under the same conditions. Full deconvolution of the XPS Mn2p3/2 core levels detects enriched Mn3+ and Mn2+ content on the surfaces, which indicates possible disproportionation/comproportionation surface equilibria. 相似文献
123.
Fluorescence Polarization Based Nucleic Acid Testing for Rapid and Cost‐Effective Diagnosis of Infectious Disease
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Dr. Ki Soo Park Prof. Richelle C. Charles Prof. Edward T. Ryan Prof. Ralph Weissleder Prof. Hakho Lee 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(46):16359-16363
A new nucleic acid detection method was developed for a rapid and cost‐effective diagnosis of infectious disease. This approach relies on the three unique elements: 1) detection probes that regulate DNA polymerase activity in response to the complementary target DNA; 2) universal reporters conjugated with a single fluorophore; and 3) fluorescence polarization (FP) detection. As a proof‐of‐concept, the assay was used to detect and sub‐type Salmonella bacteria with sensitivities down to a single bacterium in less than three hours. 相似文献
124.
Ki Dong Yang Woo Ri Ko Jun Ho Lee Prof. Sung Jae Kim Prof. Hyomin Lee Prof. Min Hyung Lee Prof. Ki Tae Nam 《Angewandte Chemie (International ed. in English)》2017,56(3):796-800
The electrocatalytic conversion of CO2 to value-added hydrocarbons is receiving significant attention as a promising way to close the broken carbon-cycle. While most metal catalysts produce C1 species, such as carbon monoxide and formate, the production of various hydrocarbons and alcohols comprising more than two carbons has been achieved using copper (Cu)-based catalysts only. Methods for producing specific C2 reduction outcomes with high selectivity, however, are not available thus far. Herein, the morphological effect of a Cu mesopore electrode on the selective production of C2 products, ethylene or ethane, is presented. Cu mesopore electrodes with precisely controlled pore widths and depths were prepared by using a thermal deposition process on anodized aluminum oxide. With this simple synthesis method, we demonstrated that C2 chemical selectivity can be tuned by systematically altering the morphology. Supported by computational simulations, we proved that nanomorphology can change the local pH and, additionally, retention time of key intermediates by confining the chemicals inside the pores. 相似文献
125.
Fevzihan Basarir Farid Sayar Irani Arif Kosemen B. Tugba Camic Faruk Oytun Bahadir Tunaboylu Hee Jeong Shin Ki Young Nam Hyosung Choi 《Materials Today Chemistry》2017
Organic photovoltaics (OPVs) are considered as a future alternative for conventional silicon based solar cells, owing to their low cost, ease of production and high-throughput. The transparent conducting electrode (TCE) is a fundamental component of OPVs. Traditionally, indium tin oxide (ITO) has been mainly utilized as a TCE in OPV applications due to its relatively high transparency and low sheet resistance. However, increasing demand for the optoelectronic devices has led to large fluctuations in ITO prices in the past decade and ITO is known to account more than 50% of the total cost of OPV devices. Thus, it is believed that development of solution-processable alternative materials is of great importance in reducing the cost of OPVs. Numerous materials, including silver nanowires, carbon nanotubes, graphene and conducting polymers, have been offered as replacements for ITO. This article reviews recent progress on fabrication of TCE via solution based coating techniques of silver nanowires (Ag NWs). In addition, performance of the Ag NWs based TCE in OPVs is summarized. Finally, we explore the future outlook for Ag NWs based TCE at the end of the review. 相似文献
126.
For the nonautonomous dynamics defined by a sequence of bounded linear operators acting on an arbitrary Hilbert space, we obtain a characterization of the notion of a nonuniform exponential dichotomy in terms of quadratic Lyapunov sequences. We emphasize that, in sharp contrast with previous results, we consider the general case of possibly noninvertible linear operators, thus requiring only the invertibility along the unstable direction. As an application, we give a simple proof of the robustness of a nonuniform exponential dichotomy under sufficiently small linear perturbations. 相似文献
127.
KNa[CoIII(OH)7{Mo6O17}] ·8H2O is obtained by ion‐exchange from a solution of K3 [Co(μ3‐OH)6Mo6O18] ·7H2O at ≈pH 1.4 using Amberlite IR120 ion exchange resin followed by concentrating the solution in a hot water bath. 相似文献
128.
129.
Ki Mun Jung Lyn C Thomas Mee Chi So 《The Journal of the Operational Research Society》2015,66(10):1656-1668
Data-based scorecards, such as those used in credit scoring, age with time and need to be rebuilt or readjusted. Unlike the huge literature on modelling the replacement and maintenance of equipment there have been hardly any models that deal with this problem for scorecards. This paper identifies an effective way of describing the predictive ability of the scorecard and from this describes a simple model for how its predictive ability will develop. Using a dynamic programming approach one is then able to find when it is optimal to rebuild and when to readjust a scorecard. Failing to readjust or rebuild a scorecard when they aged was one of the defects in credit scoring identified in the investigations into the sub-prime mortgage crisis. 相似文献
130.
Rin Jang Ki Hun Kim Shabi Abbas Zaidi Won Jo Cheong Myeong Hee Moon 《Electrophoresis》2011,32(16):2167-2173
In this study, an open‐tubular capillary electrochromatography (OT‐CEC) column with a monolithic layer of molecularly imprinted polymer (MIP) based on methacrylic acid, ethylene glycol dimethacrylate, and 4‐styrenesulfonic acid was utilized for the simultaneous separation and characterization of phospholipid (PL) molecular structures by interfacing with electrospray ionization‐tandem mass spectrometry (ESI‐MS‐MS). Introducing an MIP‐based monolith along with charged species at the OT column made it possible to separate PL molecules based on differences in head groups and acyl chain lengths in CEC. For the interface of OT‐CEC with ESI‐MS‐MS, a simple nanospray interface utilizing a sheath flow was developed and the resulting OT‐CEC‐ESI‐MS‐MS was able to separate PL standards (phosphatidylserines, phosphatidylethanolamines, phosphatidylglycerols, phosphatidic acid, and lysophosphatidylglycerols). The developed method was applied to human urinary lipid extracts, and resulted in the separation and structural identification of 18 molecules by data‐dependent collision‐induced dissociation. 相似文献