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941.
942.
A novel one-pot two-step protocol has been developed to synthesize various spiro[benzofuran-2,2′-naphthalen]-1′-one derivatives from the three-component reaction of tetralones, 2-hydroxyphenyl functionalized α,β-unsaturated ketones, and iodine. One C–C bond and one C–O bond have formed during this process. The notable features of this protocol are simple and mild reaction conditions, applicable to a wide range of readily available starting materials, good yields (up to 91%), and excellent stereoselectivities (up to 97:3). 相似文献
943.
944.
Design,synthesis and anti-influenza virus activities of terminal modified antisense oligonucleotides
Four novel terminal modified antisense oligonucleotides (ODNs) were designed, synthesized and tested for their anti-influenza virus activity. Initial biological studies indicated that lipophilic and rimantadin emodificated Flutide exhibited more potent anti-H1N1 activity than Flutide. Among them, lipophilic modificated ODN (Flutide-I) showed the most antiviral activity. The EC50 value of Flutide-I for inhibiting H1N1 induced cytopathic effect (CPE) and H1N1 RNA were respectively (0.26 ± 0.16) μM and (0.11 ± 0.03) μM. The cytotoxicity of these compounds has also been assessed. No significant cytotoxicities were found for any of these compounds with the concentrations up to 20 μM. 相似文献
945.
α-Hydroxyallylphosphinates were stereoselectively converted to γ-chloro allylphosphinates when treated with Ph3P and CCl4, via substitution of hydroxyl and migration of double bond. The reaction was promoted by phosphonium cation that acted as Lewis acid. 相似文献
946.
Chao He Xiaohui Zhang Ruofeng Huang Jing Pan Jiaqiang Li Xuege Ling Yan Xiong Xiangming Zhu 《Tetrahedron letters》2014
Under open-flask conditions, an efficient method to assemble a series of diversely functionalized diarylketones in the presence of commercially available NBS has been developed. Yields of up to 99% have been achieved employing diarylmethanes as starting material. Based on 18O-labeled experiment, the addition of stoichiometric water eventually leads to excellent yields in all carbonylation cases. 相似文献
947.
Xiaowei Yi Gongshuo Yu Jiamei Zhang Haitao Zhang Mei Li Haijun Dang 《Journal of Radioanalytical and Nuclear Chemistry》2014,299(3):1987-1991
A new method is developed for the determination of energy peak efficiency of 208 keV γ-ray of 237U based on 241Pu/237U secular equilibrium. Plutonium solution was purified to remove Am with Dowex 1 × 2 anion exchange chromatography and the concentration of 241Pu in the purified solution was determined using 242Pu isotope-dilution mass spectrometry on an inductively-coupled plasma mass spectrometry. The solution can be used as calibration source for the determination of energy peak efficiency of 208 keV γ-ray of 237U after 48 days. The method was validated for a planar HPGe detector at the 12 mm above the detector surface. The results showed that this is a simple and economic method for determining the energy peak efficiency of gamma detectors for 208 keV γ-ray of 237U. 相似文献
948.
Jinsuo Zhang 《Journal of Radioanalytical and Nuclear Chemistry》2014,299(1):517-522
Holdup in processing UF6 is analyzed in the present article. Under normal operation conditions of temperature and pressure, UF6 stays in gas phase. While if water moisture ingresses, chemical reaction between UF6 and moisture results in solid or liquid productions that can deposit on structure surfaces. The present report focuses on the chemistry of holdup and how to measure it, and safeguards and criticality safety concerns. An available statistic theoretical model is also discussed. 相似文献
949.
Shuai Guo Ling Qiu Yanming Wang Xuzhen Qin Hui Liu Manwen He Yaping Zhang Zhili Li Xiaohong Chen 《Analytical and bioanalytical chemistry》2014,406(18):4357-4370
Changes in serum lipidome and in tissue lipidome are associated with cancer. In this study, tissue mass spectrometry imaging (MSI) and serum lipid profiling by matrix-assisted laser desorption/ionization-Fourier transform ion cyclotron resonance mass spectrometry (MALDI-FTICR MS) were performed to investigate significantly changed lipids in both tumor (malignant thyroid cancer (MTC) and benign thyroid tumor (BTT)) tissues and sera. Y-scatterplots of variable importance in the projection (VIP) values vs. fold change values indicate that change trends in the levels of ten lipids (i.e., phosphatidylcholine (PC)(34:1), PC(36:1), PC(38:6), phosphatidic acid (PA) (36:2), PA(36:3), PA(38:3), PA(38:4), PA(38:5), PA(40:5), and sphingomyelin (SM)(34:1)) in both tissues and sera from MTC patients, BTT patients, and normal individuals are significantly associated with these three types of pathophysiological status. In order to examine their diagnostic ability, 289 serum samples from 124 MTC patients, 43 BTT patients, and 122 normal controls were randomly divided into the training set and validation set. A biomarker of PC(34:1) exhibited excellent diagnostic ability to differentiate both MTC and BTT patients from normal individuals, with an area under the receiver operating characteristic (ROC) curve value of 0.984, a sensitivity of 96.4 %, and a specificity of 92.7 %. A panel which included PA(36:3) and SM(34:1) could distinguish between MTC and BTT, with an area under receiver operating characteristic curve (AUC) of 0.961, a sensitivity of 87.8 %, and a specificity of 92.9 %. It is worth noting that a panel consisting of PC(34:1), PA(36:3), and SM(34:1) could differentiate MTC patients from both BTT patients and normal individuals, with an AUC of 0.841, a sensitivity of 86.6 %, and a specificity of 75.5 %. Figure
Comparison of tissue lipid Profiling and serum lipid profiling using MALDI-FTICR MS to select thyroid disease-specific lipids 相似文献
950.
Hao Zhang Hui Huang Zihan Lin Xingguang Su 《Analytical and bioanalytical chemistry》2014,406(27):6925-6932
Graphene is a two-dimensional carbon nanomaterial one atom thick. Interactions between graphene oxide (GO) and ssDNA containing different numbers of bases have been proved to be remarkably different. In this paper we propose a novel approach for turn-on fluorescence sensing determination of glucose. Hydrogen peroxide (H2O2) is produced by glucose oxidase-catalysed oxidation of glucose. In the presence of ferrous iron (Fe2+) the hydroxyl radical (?OH) is generated from H2O2 by the Fenton reaction. This attacks FAM-labelled long ssDNA causing irreversible cleavage, as a result of the oxidative effect of ?OH, producing an FAM-linked DNA fragment. Because of the weak interaction between GO and short FAM-linked DNA fragments, restoration of DNA fluorescence can be achieved by addition of glucose. Due to the excellent fluorescence quenching efficiency of GO and the specific catalysis of glucose oxidase, the sensitivity and selectivity of this method for GO-DNA sensing are extremely high. The linear range is from 0.5 to 10 μmol L?1 and the detection limit for glucose is 0.1 μmol L?1. The method has been successfully used for analysis of glucose in human serum. Figure
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