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71.
72.
73.
Guo Zhijun Niu Yanning Zhang Weiguang Tan Minyu 《Journal of Radioanalytical and Nuclear Chemistry》2004,262(2):331-337
N,N,N',N',N',N'-Hexaethyl-2,2′,2'-(nitrilotrisethyleneoxy-2-benzyloxy)tris(acetamide) (L3) has been prepared and characterized
by using IR, 1H NMR and positive-ion FAB mass spectra. The extraction of Th4+ and UO2
2+ with N,N,N',N',N',N'-hexaethyl-2,2',2'- (nitrilo-trisethyleneoxy)tris(acetamide) (L1), N,N,N',N',N',N'-hexaisopropyl-2,2',2'-(nitrilotrisethyleneoxy)tris(acetamide)
(L2), and L3 was studied at 20±1 °C as a function of diluent, concentration of free extractant in organic phase and concentration
of picrate in aqueous phase. It was found that the extracting powers of L1 and L2 for Th4+ are almost identical. The extracting power of L2 for UO22+ was slightly higher than that of L1. The difference in terminal
groups (ethyl or isopropyl) of the extractants (L1 and L2) with same backbone has a little effect on the extracting power
for both Th4+ and UO22+. The extracting powers of L3 for both Th4+ and UO22+ were larger than those of L1 and L2. The extractants
(L1 and L3) having the same terminal group (ethyl) with different backbones have obviously different extracting powers for
Th4+ or UO22+. The extracting powers of all three extractants L1, L2, and L3 for Th4+ were larger than those for UO22+. The
compositions of extracted species in organic phase were predominantly ThL(Pic)3NO3 and UO2L(Pic)NO3, respectively (L denotes
L1, L2 and L3).
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
74.
Nafion membranes were modified by chemical polymerization of aniline using ammonium peroxodisulfate as the oxidant. The Nafion-polyaniline composite membranes were extensively characterized using scanning electron microscopy (SEM), atomic force microscopy (AFM), infrared (FTIR-ATR) and X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and ion-exchange capacity measurements. The transport properties were also evaluated by conductivity and electrodialysis measurements. The data show that when a high oxidant concentration (1 M (NH4)2S2O8) is used, polyaniline is mostly formed at the surface of the Nafion membrane with a higher proportion of oligomers. On the contrary, when 0.1 M oxidant is used, polyaniline is mostly formed inside the ionic domains of Nafion, blocking the pathway to ion transport and thus reducing the transport of Zn2+ as well as the transport of H+. These data were also compared to the data obtained with poly(styrene sulfonate)-PANI composite membranes. 相似文献
75.
An efficient and feasible synthetic approach was developed for the synthesis of an array of new flavane derivafives from the substituted benzaldehyde with the reduction of chalcones and subsequent cyclization as the key steps. The purity and structure of the products were confirmed by the elemental analysis and a combination of its IR, ^1H and ^13C NMR, and mass spectra. These synthetic compounds were tested for xanthine oxidase (XO) inhibitions and antifungal actions against Candida albicans, Cryptococcus neoformans, Aspergillus sp. and Trichophyton rubrum. 7-Hydrazinocarbonylmethoxy-4'-methoxyflavane (9) was found to be the most XO inhibitory with IC50=76.4 μmol/L, and the most potent antifungal compound was 4'-hydrazinocarbonylmethoxyflavane (12) with minimal inhibition concentration MIC=8 μg/mL against Trichophyton rubrum. 相似文献
76.
Intracellular delivery of enzymes is essential for protein-based diagnostic and therapeutic applications. Protein-spherical nucleic acids (ProSNAs) defined by protein core and dense shell of oligonucleotides have been demonstrated as a promising vehicle-free enzyme delivery platform. In this work, we reported a crosslinking strategy to vastly improve both delivery efficiency and intracellular sensor performance of ProSNA. By assembling individual ProSNA with lactate oxidase (LOX) core into a nanoscale particle, termed as crosslinked SNA (X-SNA), the enzyme delivery efficiency increased up to 5–6 times higher. The LOX X-SNA was later demonstrated as a ratiometric probe for quantitative detection of lactate in living cells. More importantly, X-SNA probe showed significantly improved sensor performance with signal-to-noise ratio 4 times as high as ProSNA when detecting intracellular lactate.By crosslinking protein spherical nucleic acid (SNA) into a supramolecular architecture X-SNA, the intracellular enzyme delivery efficiency was significantly enhanced, showing 3–4 times higher signal-to-noise ratio in detecting intracellular lactate. 相似文献
77.
The cold and heat denaturations of bovine P-lactoglobulin A ((β-lg A) has been studied in solutions of guanidine hydrochloride
(GuHCI) by differential scanning calorimetry (DSC). The experimental results are presented and discussed. It is shown that
the number of protons bound by the monomeric molecules of β-lg A was unchanged before and after its heat denaturation below
pH 3, and that the activation energy of the heat denaturation was depressed owing to the presence of GuHCI. In the solutions
with 2.50 and 3.06 mol/L of GuHCI, both the cold and heat denaturations of P-lg A were observed. In comparison with the heat
denaturation, the activation energy of cold denaturation was far lower and the number of GuHCl molecules bound by the unfolded
polypeptide chains after culd denaturation increased a lot. The absolute value of the enthalpy of cold denaturation was larger
than that of heat denaturation. It was found by the analysis that the contribution to the total denaturational enthalpy of
conformational change itself of the monomeric molecules of β-lg A was the lowest among the globulins, according to the average
of the number of heavy atoms.
Project supported by the National Natural Science Foundation of China, and by the fund for excellent items under Director
of the Institute of Chemistry. 相似文献
78.
M. J. O'Hare E. Tan C. Rehm P. Grebow B. Loev E. Neiss 《Journal of heterocyclic chemistry》1983,20(3):819-820
Indapamide ( 1 ) is readily oxidized with mild oxidizing agents to the indole derivative 2 . Dehydrogenation of indapamide is a convenient one step synthesis of a complex indole compound. 相似文献
79.
Aromatization of methane over different Mo-supported catalysts in the absence of oxygen 总被引:2,自引:0,他引:2
Tan Pinglian Xu Zhusheng Zhang Tao Chen Liayuan Lin Liwu 《Reaction Kinetics and Catalysis Letters》1997,61(2):391-396
Both acidity and structure of the support are important factors in converting methane to aromatics. Lower SiO2/Al2O3 ratio seems to favor the aromatization of methane over the Mo/HZSM-5 catalyst. When Pt is added as a modifier the activity
of Mo/HZSM-5 catalyst will decrease slightly, but coke formation will enhanced. 相似文献
80.
Monuron (C9H11ClN2O; N,N-dimethyl-N′-(4-chlorophenyl) urea, CAS 150-68-5) was synthesized and the heat capacities of the compound were measured in the temperature range from 79 to 385 K with a high precision automated adiabatic calorimeter. No phase transition or thermal anomaly was observed in this range. The enthalpy and entropy data of the compound relative to the reference temperature 298.15 K were derived based on the heat capacity data. The thermodynamic properties of the compound were further investigated through DSC and TG analysis. The melting point, the molar enthalpy, and entropy of fusion were determined to be 447.6±0.1 K, 29.3±0.2 kJ mol−1, and 65.4 J K−1 mol−1, respectively. 相似文献