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101.
Products of reaction between the organoselenium xenobiotic, diacetophenonyl selenide (1,5-diphenyl-3-selenapenta-1,5-dione), and reduced glutathione at different molar ratios and pH values were studied by HPLC and TLC. Reaction intermediates, S-(acetophenylselenyl)glutathione and glutathione selenodisulfide, and reaction products, acetophenone and hydroselenide anion, were detected. The reaction scheme proposed earlier was confirmed.  相似文献   
102.
The suitability of the determination of the asymmetry factor of chromatographic peaks by the ratio of areas of two components separated by a perpendicular dropped from the maximum of the peak to the base-line, A s * = S b /S a , where symbol a corresponds to the leading edge of the peak and b is for its tailing slope, is discussed. It is demonstrated that this method enables the estimation of the asymmetry of even partially separated chromatographic signals, including those eluted “in the tail” of intense peaks of solvents. The concepts of the asymmetry index I(A s *) and its increment ΔI(A s *) = (A s *)–I(A s *) are introduced, which ensures the characterization of the asymmetry of peaks of polar analytes with respect to the asymmetry of nonpolar reference components, that is, the separation of the effects of the polarity of analytes and their quantities injected into the chromatographic column on this parameter. For the first time we revealed a correlation of the asymmetry factors of compounds of different chemical nature with such a characteristic of their polarity as the difference in chromatographic separation temperature and the normal boiling point of analytes.  相似文献   
103.
The solution state and thermodynamic stability of complexes of the new antituberculosis agent 1,4-bis(amidomethylsulfinyl)butane (L) with iron(III), copper(II), cobalt(II), nickel(II), and manganese(II) in an aqueous solution in the presence and in the absence of the nonionic surfactant Brij 35 were studied by spectrophotometry, pH potentiometry, NMR relaxation technique (T = 25 °C; variable ionic strength), and mathematical simulation. The geometry optimization of all structures was carried out by the molecular mechanics method MM2 in order to obtain data on coordination modes. In addition, the structure of 1,4-bis(amidomethylsulfinyl)butane was refined by the DFT/B3LYP/6-311++G(d,p) quantum chemical method using the IEFPCM model to take into account solvent effects. In an aqueous solution (in the concentration range of 1.3?10–5—1?10–3 mol L–1) and in the presence of Brij 35, 1,4-bis(amidomethylsulfinyl)butane exists as a neutral monomer. The Beer—Lambert—Bouguer law is obeyed in a wide concentration range for compound L in an aqueous solution, as well as in the presence of the surfactant, which can be used for the quantification of compound L. Iron(III), cobalt(II), and nickel(II) were shown to form 1: 1 mononuclear complexes with L; and copper(II) forms, 1: 1 and 2: 2 complexes. The presence of Brij 35 in the Cu2+L system at a micellar concentration promotes the formation of a dinuclear complex.  相似文献   
104.
The CoCl2-catalyzed reactions of fluorinated 1,2-oxi- and thiiranes with acyl chlorides were studied. It was found that a regioselective heterocycle opening reaction resulted in two isomers having normal and abnormal structure in a ratio predetermined by the substituents in both the starting heterocycles and acyl chlorides.  相似文献   
105.
A general approach to the synthesis of new 3-acetyl-substituted pyrrolo[3,4-f]indole-5,7-diones, 3-[3-(dimethylamino)acryloyl]-1-methoxypyrrolo[3,4-f]indole-5,7-diones and similar indole-5,6-dicarbonitriles has been developed. Dimethylaminoacryloyl derivatives synthesized on their basis regioselectively reacted with hydrazine hydrochlorides and hydroxylamine with the formation of the corresponding 5-substituted azoles.  相似文献   
106.
A reaction of R-adamant-1-yl isocyanates with 4-[(4-aminocyclohexyl)oxy]benzoic acid and 1-(4-aminopiperidin-1-yl)propan-1-one in DMF afforded corresponding ureas in 90—95% yield, the target-oriented inhibitors of epoxide hydrolase sEH. The ureas are characterized by reduced melting points and increased solubility in water, as well as by inhibitory activity in the range of 0.5—4.0 nmol L–1.  相似文献   
107.
Pino  F.  Stevanato  L.  Fabris  D.  Barros  H.  Vidal  A.  Nebbia  G.  Lunardon  M.  Moretto  S.  Sajo-Bohus  L. 《Journal of Radioanalytical and Nuclear Chemistry》2017,314(3):1833-1839

A compact and modern equipment for implementing the fast neutron and γ-ray transmission technique (FNGT) has been developed in order to estimate the sulphur content of crude oil. FNGT is employed for non- destructive analysis of different kinds of samples. The compact system presented in this work represents an improvement of our previous experimental set-up [1, 2]. It makes use of a 252Cf source, an EJ-301 liquid scintillator detector (2″ × 2″) with excellent n/γ discrimination capabilities, and modern nuclear electronics based on fast digitizers. The fast neutron and gamma transmission technique was employed to study a system for on-line sulphur concentration measurement in Venezuelan heavy sour oil. The range of sulphur concentrations investigated is between 0.1 and 6.5 wt%. The equipment performances and limitations are compared with those predicted by a Monte Carlo model built in GEANT4 v10.01. The results show the possibility to implement a compact unit for on-line determination of sulphur concentration in crude oil.

  相似文献   
108.
The aim of this paper is characterisation of mesomorphic properties and helical structure parameters: handedness and helical pitch, of two laterally substituted ferroelectric compounds and mixtures based on them. These compounds have the same quaterphenyl rigid core and the same length of non-chiral chain – eight carbon atoms, as well as the absolute configuration of chiral centre (‘R’). Base compounds differ in the kind of a substituent in a rigid core (–Cl, –CH3). Both of them have rather low melting temperature in comparison to most of quaterphenyls, and it affects the lowering of this temperature in binary mixtures. Thus they can be used for preparation of multicomponent ferroelectric mixtures useful for application.  相似文献   
109.
Poly(dodecylmethacrylate-co-methyleugenol) P(DDMA-co-Meu) and poly(dodecylmethacrylate-co-methylchavicol) P(DDMA-co-Mch) gels were synthesized in ethanol using free radical cross-linking polymerization method at 60 °C for 24 h in the presence of azobisisobutyronitrile (AIBN) and triethylene glycol dimethacrylate (TEGDMA) as initiator and cross-linker, respectively. Scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR) were used to characterize the gels. These gels were used to investigate swelling behaviors in linalool and methyl eugenol, in essential oil mixture of phenyl propanoid and terpenoid, and also in various solvents. While the equilibrium swelling values (ESV) of both gels were higher in linalool than in methyl eugenol, the result was vice versa in the case of essential oil mixture. ESVs of both gels were also obtained in various solvents with different functional groups and the highest ESV of both gels were obtained in toluene, and the lowest ESV of P(DDMA-co-Meu) and P(DDMA-co-Mch) was in methanol and in ethylene glycol, respectively. While P(DDMA-co-Meu) is sensitive to carbon number change in alcohol, P(DDMA-co-Mch) is less sensitive. In the case of esters, increase of carbon number in functional group causes a more significant change in ESV than an increase of carbon number in aliphatic chain. Experimental results were correlated by the first-order and second-order models. The second-order model was more suitable than the other. While P(DDMA-co-Meu) gel swelled in linalool exhibits a Fickian diffusion character, the diffusion mechanism of the gel in methyl eugenol is a non-Fickian one. In the case of P(DDMA-co-Mch), the result is vice versa.  相似文献   
110.
We study Sobolev inequalities on doubling metric measure spaces. We investigate the relation between Sobolev embeddings and lower bound for measure. In particular, we prove that if the Sobolev inequality holds, then the measure μ satisfies the lower bound, i.e. there exists b such that μ(B(x,r))≥b r α for r∈(0,1] and any point x from metric space.  相似文献   
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