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51.
β—(酚酯基)乙基锗倍半氧化物的合成及对体外培养细胞的作用 总被引:7,自引:1,他引:7
β-羧基乙基锗倍半氧化物(即Ge-132)是一种无毒和具较强抗癌活性的有机锗化合物。为了进一步提高其抗癌活性。已对Ge-132进行了化学结构修饰。本文介绍8种未见报导的Ge-132衍生物,β-酚酯基乙基锗倍半氧化物的合成和体外培养细胞实验结果。 相似文献
52.
Deng Y Wang D Xiao W Jin X Hu X Chen GZ 《The journal of physical chemistry. B》2005,109(29):14043-14051
A thin layer model is proposed to assist in the understanding of the electrochemical conversion of insulator to conductor at the conductor/insulator/electrolyte three-phase interline (3PI) when the influence of mass diffusion in the electrolyte phase is negligible. The model predicts, under potentiostatic conditions, a linear variation of the current or the length of the 3PI with time. When polarization is sufficiently large, the logarithm of the current/time ratio or the 3PI-length/time ratio, according to the model, increases linearly with the applied potential. These predictions were tested against and agreed very well with two practical systems: the electroreduction of solid AgCl to Ag in aqueous KCl and of solid SiO2 to Si in molten CaCl2. Kinetic parameters were derived from experimental data using the model. Particularly, the electron transfer coefficient, alpha, was found to be about 0.29 for the reduction of AgCl to Ag in the aqueous KCl solution at room temperature but about 10(-2) for the reduction of SiO2 to Si in molten CaCl2 at 850 degrees C. 相似文献
53.
Cimidahuside 1 and 2, two new cyclolanostanol xylosides from the aerial parts of Cimicifuga dahurica
Cimidahuside 1 and 2, two new cyclolanostanol xylosides were isolated from the aerial parts of Cimicifuga dahurica (Turcz.) MAXIM, on the basis of spectral data and chemical evidences, their structures were determined to be (20R,24R)-24,25-epoxy-3-beta-(beta-D-xylopyranosyloxy)-9,19-cyclolanost-7-ene-16,23-dione (1), and (20R,24R)-24,25-epxy-15-alpha-hydroxy-3-beta-((bet-D-xylpyranosyoxy)-9,19-cyclanost-7-ene-16,23-dione (2), respectively. 相似文献
54.
Wei-Ming Wang Dihua Dai Jia-Rui Wu Chun-Yu Wang Prof. Yan Wang Prof. Ying-Wei Yang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(46):11879-11887
An efficient strategy for simultaneously detecting and removing Hg2+ from water is vital to address mercury pollution. Herein a supramolecular assembly G ⊂ H with photoluminescent properties is facilely constructed through the self-assembly of a functional pillar[5]arene bearing two N,N-dimethyldithiocarbamoyl binding sites ( H ) and an AIE-active tetraphenylethene derivative ( G ). Remarkably, the fluorescence of G ⊂ H can be exclusively quenched by Hg2+ among the 30 cations due to the formation of non-luminous ground state complex and only L-cysteine can restore fluorescence in the common 20 amino acids. Meanwhile, the probe G ⊂ H has a considerable thermal and pH stability, a good anti-interference property from various cations, and a satisfactory sensitivity. More importantly, G ⊂ H exhibits a prominent capability of Hg2+ removal with rapid capture rate (within 1 h) and excellent adsorption efficiency (98 %), as well as a highly efficient recyclability without losing any adsorption activity. 相似文献
55.
Yongfu Li Dihua Sun Weining Liu Min Zhang Min Zhao Xiaoyong Liao Liang Tang 《Nonlinear dynamics》2011,66(1-2):15-28
A new car-following model termed as multiple headway, velocity, and acceleration difference (MHVAD) is proposed to describe the traffic phenomenon, which is a further extension of the existing model of full velocity difference (FVD) and full velocity and acceleration difference (FVAD). Based on the stability analysis, it is shown that the critical value of the sensitivity in the MHVAD model decreases and the stable region is apparently enlarged, compared with the FVD model and other previous models. At the end, the simulation results demonstrate that the dynamic performance of the proposed MHVAD model is better than that of the FVD and FVAD models. 相似文献
56.
Inside Cover: Activity Enhancement of G‐Quadruplex/Hemin DNAzyme by Flanking d(CCC) (Chem. Eur. J. 12/2016) 下载免费PDF全文
57.
Effects of chain entanglement on liquid-liquid phase separation behavior of LCST-type polymer blends: Cloud point and decomposition rate 总被引:1,自引:0,他引:1
By preparing homogenous blend samples with different degrees of chain entanglement, we report an anomalous contribution of chain entanglement to phase separation temperature and rate of poly(methyl methacrylate)/poly(styrene-comaleic anhydride)(PMMA/SMA) blends presenting a typical lower critical solution temperature(LCST) behavior. The meltmixed PMMA/SMA blends with a higher chain entanglement density present a lower cloud point(Tc) and shorter delay time, but lower phase separation rate at the given temperature than solution-cast ones, suggesting that for the polymer blends with different condensed state structure, thermodynamically more facilitation to phase separation(lower Tc) is not necessarily equivalent to faster kinetics(decomposition rate). The experimental results indicate that the lower Tc of melt-mixed sample is ascribed to smaller concentration fluctuation wavelength(Λm) induced by higher entanglement degree, while higher entanglement degree in melt-mixed sample leads to a confined segmental dynamics and consequently a slower kinetics(decomposition rate) dominated by macromolecular diffusion at a comparable quench depth. These results reveal that the chain packing in polymer blends can remarkably influence the liquid-liquid phase separation behavior, which is a significant difference from decomposition of small molecular mixtures. 相似文献
58.
The authors prove the local unramified correspondence for a new type of construction
of CAP representations of even orthogonal groups by a generalized automorphic
descent method. This method is expected to work for all classical groups. 相似文献
59.
Direct electron transfer of myoglobin (Mb) was achieved by its direct immobilization on carbon ionic liquid electrode (CILE) with a conductive hydrophobic ionic liquid, 1‐butyl pyridinium hexaflourophosphate ([BuPy][PF6]) as binder for the first time. A pair of well‐defined, quasi‐reversible redox peaks was observed for Mb/CILE resulting from Mb redox of heme Fe(III)/Fe(II) redox couple in 0.1 M phosphate buffer solution (pH 7.0) with oxidation potential of ?0.277 V, reduction potential of ?0.388 V, the formal potential E°′ (E°′=(Epa+Epc)/2) at ?0.332 V and the peak‐to‐peak potential separation of 0.111 V at 0.5 V/s. The average surface coverage of the electroactive Mb immobilized on the electrode surface was calculated as 1.06±0.03×10?9 mol cm?2. Mb retained its bioactivity on modified electrode and showed excellent electrocatalytic activity towards the reduction of H2O2. The cathodic peak current of Mb was linear to H2O2 concentration in the range from 6.0 μM to 160 μM with a detection limit of 2.0 μM (S/N=3). The apparent Michaelis–Menten constant (K and the electron transfer rate constant (ks) were estimated to be 140±1 μM and 2.8±0.1 s?1, respectively. The biosensor achieved the direct electrochemistry of Mb on CILE without the help of any supporting film or any electron mediator. 相似文献
60.
A new composite film of microbial exocellular polysaccharide‐gellan gum (GG) and hydrophilic room temperature ionic liquid 1‐butyl‐3‐methyl‐imidazolium tetrafluoroborate (BMIMBF4) was firstly used as an immobilization matrix to entrap horseradish peroxidase (HRP), and its properties were studied by UV/vis spectroscopy, cyclic voltammetry and electrochemical impedance spectroscopy. The results showed that BMIMBF4 could promote the electron transfer between HRP and electrode surface, and the existence of GG could successfully immobilize BMIMBF4 on the electrode surface with improved stability. HRP–BMIMBF4–GG/GCE exhibited a pair of well‐defined and quasireversible cyclic voltammetric peaks in 0.1 M pH 7.0 phosphate buffer solutions at 1.8 V/s, which was the characteristic of HRP Fe(III)/Fe(II) redox couples. The formal potentials (E°′) was ?0.368 V (vs. SCE) and the peak‐to‐peak potential separation (ΔEP) was 0.058 V. The peak currents were five times as large as those of HRP–GG/GCE. The average surface coverage (Γ*) and the apparent Michaelis‐Menten constant (Km) were 4.5×10?9 mol/cm2 and 0.67 μM, respectively. The electron transfer rate constant was estimated to be 15.8 s?1. The proposed electrode showed excellent electrocatalytic activity towards hydrogen peroxide (H2O2). The linear dynamic range for the detection of H2O2 was 0.05–0.5 μM with a correlation coefficient of 0.9945 and the detection limit was estimated at about 0.02 μM (S/N=3). BMIMBF4–GG composite film was promising to immobilize other redox enzymes or proteins and attain their direct electrochemistry. 相似文献