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1.
Physics of Particles and Nuclei Letters - Plastic scintillators are widely used in detecting nuclear radiation due to their low construction cost, the ability to be produced in nearly any shape and...  相似文献   
2.
The interactions of colchicine (COL) and aspirin (ASA) with human hemoglobin (HB) was studied by fluorescence, UV/vis absorption, resonance light scattering, synchronous fluorescence and circular dichroism (CD) spectroscopic techniques under physiological conditions. The inherent binding information, including the quenching mechanism, binding constants, number of binding sites, effective quenching constant, fraction of the initial fluorescence and thermodynamic parameters were determined by the fluorescence quenching technique at different temperatures. The results proved that the mechanism of fluorescence quenching of HB by COL and ASA is due to formation of HB–drug complexes in the binary and ternary systems. The distance between the acceptor drugs and HB was estimated by Förster’s equation on the basis of fluorescence energy transfer. In addition, according to the synchronous fluorescence spectra of HB, the results showed that the fluorescence quenching of HB originated solely from the tryptophan residues and indicated a conformational change for HB caused by addition of the drugs. Far-UV CD spectra of HB were recorded before and after the addition of ASA and COL both as binary and ternary systems. An increase in intensity of the positive CD peak of HB was observed in the presence of these drugs. The results were interpreted as excited state interactions between the aromatic residues of the HB binding sites and the drugs bound to them.  相似文献   
3.
We report on conductometric study of complexation between benzylbisthiosemicarbazone [(2E,2′E)-2,2′-(1,2-diphenylethane-1,2-diylidene)bis(hydrazine-1-carbothioamide)] with Zn2+, Cr3+, Co2+, and Ni2+ cations at different temperatures in acetonitrile-dimethylformamide binary solvents of varied composition. The equilibrium constant and standard thermodynamic parameters (Δc H 0 and Δc S 0) of the complexes formation have been determined and found to be dependent on the binary solvent composition, the metal ion nature, and temperature.  相似文献   
4.
β‐Aminoalcohols were synthesized in high yields by reaction of epoxides with amines in the presence of MCM‐41 as a green and reusable catalyst under solvent‐free conditions.  相似文献   
5.
A simple, rapid, and highly sensitive method for simultaneous analysis of anti‐inflammatory drugs (naproxen, ibuprofen, and mefenamic acid) in diluted human serum was developed using the electrochemically controlled solid‐phase microextraction coupled to ion mobility spectrometry. A conducting molecularly imprinted polymer film based on polypyrrole was synthesized for the selective uptake and release of drugs. The film was prepared by incorporation of a template molecule (naproxen) during the electropolymerization of pyrrole onto a platinum electrode using cyclic voltammetry method. The measured ion mobility spectrometry intensity was related to the concentration of analytes taken up into the films. The calibration graphs (naproxen, ibuprofen, and mefenamic acid) were linear in the range of 0.1–30 ng/mL and detection limits were 0.07–0.37 ng/mL and relative standard deviation was lower than 6%. On the basis of the results obtained in this work, the conducting molecularly imprinted polymer films as absorbent have been applied in the electrochemically controlled solid‐phase microextraction and ion mobility spectrometry system for the selective clean‐up and quantification of trace amounts of anti‐inflammatory drugs in human serum samples. Scanning electron microscopy has confirmed the nano‐structure morphology of the polypyrrole film.  相似文献   
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7.
We report here two simple methods for the synthesis of benzo[c]acridine derivatives from three-component, one-pot condensation of 1-naphthylamine, dimedone, and a variety of substituted aldehydes in the presence of a catalytic amount of NH2SO3H or H6P2W18O62 · 18H2O under solvent-free conditions at 120 °C or in refluxing ethanol.  相似文献   
8.
An ion imprinted silica sorbent was prepared using a sol–gel process for selective extraction of Ni(II) ions from water samples. Bis(dibenzoylmethanto)nickel(II) complex was used as template; phenyltrimethoxysilane and 3-aminopropyltriethoxysilane as functional monomers and tetraethylorthosilicate as reticulating agent. The material was packed in solid-phase extraction (SPE) column. The effect of sampling volume, elution conditions, sample pH and sample flow rate on the extraction of Ni ions from water samples were studied. The relative selectivity coefficients of imprinted sorbent for Ni(II)/Co(II), Ni(II)/Cu(II) and Ni(II)/Cd(II) were 23.7, 30.3 and 24.4, times greater than non-imprinted sorbent, respectively. The relative standard deviation of the eight replicate determinations of Ni(II) was 4.2%. The detection limit was 0.9 µg L?1 using flame atomic absorption spectrometry. The developed method was successfully applied to the determination of trace nickel in water samples.  相似文献   
9.
Highly dispersed palladium nanoparticles supported on carbon nanofibers, which show high catalytic activity and stability in the hydrogenation of cyclooctene, were synthesized by the two-step metal organic chemical vapor deposition (MOCVD) of allylcyclopentadienylpalladium (Pd(allyl)Cp) as precursor at atmospheric pressure.  相似文献   
10.
A new series of amphiphilic β-cyclodextrins were designed and synthesized by grafting peptide chains on to all primary hydroxyl groups via ester bond formation. The desired amphiphilic structures have been produced from ester connection between the C-6 of β-cyclodextrin and the carboxyl group of N-acetylated resides: H2N-Leu-COOH, H2N-Leu-Gly-COOH, H2N-Leu-Gly-Leu-COOH, and H2N-Leu-Gly-Leu-Gly-COOH (3a-d). The synthetic pathway involves selective bromination of all primary hydroxyls of β-cyclodextrins and then substitution with the carboxylate moiety of the mentioned N-acetyl residues in the presence of DBU (1,8-diazabicyclo[5,4,0]undec-7-ene). The ability of the synthetic compounds for extraction and phase transfer of glucosamine, as a hydrophilic organic compound, was then studied. The results showed a considerable ability of these amphiphilic compounds for extraction and a selective tendency of 3c for phase transfer of glucosamine.  相似文献   
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