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排序方式: 共有220条查询结果,搜索用时 15 毫秒
1.
František Kopecký Božena Kopecká Pavol Kaclík 《Journal of inclusion phenomena and macrocyclic chemistry》2001,39(3-4):215-217
The solubility of nimodipine was measured in aqueous solutions of the following cyclodextrins: -cyclodextrin (-CD), hydroxypropyl--CD (HP--CD), -cyclodextrin (-CD), random substituted methyl--CD (M--CD), three hydroxypropyl--CDs (HP--CD) with mutually different average degree of substitution, and hydroxypropyl--cyclodextrin (HP--CD). From the determined linear solubility diagrams the values of the binding constant K11 of the inclusion complexes of nimodipine with the respective CDs were evaluated. The -CDs efficiently solubilized sparingly soluble nimodipine, the highest value of K11 was found for M--CD (1680 M-1), followed by -CD (550 M-1) and HP--CDs, where the higher degree of substitution lowered K11. Only slight solubilization of nimodipine was observed in the solutions of the -CDs and HP--CD. 相似文献
2.
A. D'Aprano I. D. Donato F. Pinio V. Turco Liveri 《Journal of solution chemistry》1989,18(10):949-955
A calorimetric method to evaluate, at the same time, the distribution constant and the standard enthalpy of transfer of a solute partitioned between organic phase and reversed micelles is proposed. The method was applied to the partition of methanol, 1-propanol and 1-pentanol between n-heptane and AOT reversed micelles containing water at 25°C. The results show that the distribution constant decreases as the alcohol alkyl chain length increases and that the solubilization site can change as the water content of reversed AOT micelles increases. In particular, at sufficiently high water content, methanol seems to be preferably solubilized in the aqueous pseudophase whereas 1-pentanol prefers always the palisade layer as site of solubilization.In part from Doctor in Biology thesis of F. Pinio, University of Palermo, Italy. 相似文献
3.
Studies on Phase Behavior of Alkyl Polyglucoside Based on Microemulsions with Modified Fishlike Phase Diagram 总被引:1,自引:0,他引:1
JinLingCHAI GanZuoLI ZhaoYuDIAO GaoYongZHANG 《中国化学快报》2004,15(3):361-364
The three-phase behavior in the quaternary system of an alkyl (C8/10^- or C12/14^-)polyglucoside / 1-butanol / n-octane / water has been studied at 40℃ with the modified fishlike phase diagram, which is presented by us for the first time. The mass fraction of 1-butanol in the hydrophile-lipophile balanced interfacial layer, A^S, the coordinates of the start point B and the end point E of the phase diagram, and the solubilities of alkyl polyglucoside and 1-butanol in n-octane phase were calculated. The solubilization of the microemulsion was also discussed. 相似文献
4.
5.
The membrane-water partition coefficient of the detergent C12E7 between water and C12E7/POPC mixed membranes has been determined by means of steady-state fluorescence spectroscopy. The emission spectra of the fluorescent probe Laurdan were used as an indicator of membrane composition at different membrane concentrations in the sample. The partition coefficient expressed as the ratio of the mole fractions of the detergent in the membrane and water phases is about 6*105 at low molar ratios of C12E7/POPC (R
c
) and decreases rapidly with increasingR
c
. The limiting detergent content of the lamellar phase (R
c
*
>0.8) is indicated by a minimum ofP(R
c
). 相似文献
7.
Alain H. Roux Daniel Hétu Gérald Perron Jacques E. Desnoyers 《Journal of solution chemistry》1984,13(1):1-25
Mixed micelles can be formed in water between various pairs of hydrophobic solutes such as surfactants, alcohols and hydrocarbons. These systems can often be studied through the thermodynamic functions of transfer of one of the solutes, usually kept near infinite dilution, from water to an aqueous solution of the other solute. When mixed micelles are formed, these functions change significantly, and often go through extrema, in the region where the binary system micellizes or undergoes some microphase transition.Three main effects are responsible for the observed trends: pair-wise interactions between both solutes in the monomeric form, a distribution of the reference solute between the aqueous and micellar phases and a shift in the monomer-micelle equilibrium in the vicinity of the reference solute. Simple equations can be derived for these three effects which can account for the sign and magnitude of the observed trends using parameters which are derived for the most part from the two binary systems. 相似文献
8.
Bunai K Ariga M Inoue T Nozaki M Ogane S Kakeshita H Nemoto T Nakanishi H Yamane K 《Electrophoresis》2004,25(1):141-155
We analyzed ABC transporter solute-binding proteins (SBPs) of the Bacillus subtilis membrane using a proteomic approach. We prepared a washed cell membrane fraction that was insoluble in 134 mM nondetergent sulfobetaine and then extracted proteins using mixtures of detergents in a stepwise manner. The membrane proteins were resolved by three two-dimensional polyacrylamide gel electrophoresis (2-D PAGE) or two one-dimensional (1-D) PAGE procedures, electroblotted, and digested in the presence of 5% or 80% acetonitrile. Thereafter, matrix-assisted laser desorption/ionization-time of flight-mass spectrometry (MALDI-TOF MS) identified 637 proteins corresponding to 15.9% of the total cellular proteins. We predicted that among these, 256 were membrane proteins, 101 were lipoproteins or secretory proteins and 280 were soluble proteins containing peripheral proteins that function in both the cytoplasm and the cell membrane such as SecA and FtsY. Among the 637 proteins, we identified 30 SBPs among 38 importers predicted by a bioinformatic search of the genome. We confirmed expression of the genes for the 30 SBPs using DNA microarray analysis. We compared the 2-D gel separation profiles of submembrane fractions solubilized by 1% n-dodecyl-beta-D-maltoside from cells cultured on Luria Bertani (LB), S7, and S7 medium without glutamate as well as DNA microarray data on LB and S7. The results suggested that YcdH, YtmK and YurO are binding proteins for Mn(++), glutamate and glucose, respectively, and that YqiX and YxeM are binding proteins for amino acids (tryptophan in S7 medium). 相似文献
9.
The solubilities of methane, ethane, propane, and n-butane were measured in aqueous solutions of sodium dodecylsulfate (NaDS) (0–0.1M) from 15 to 27°C. From these measurements the standard Gibbs energies, entropies, and enthalpies for the process of transferring the solute molecules from the gaseous phase into the solutions were calculated. An approximate relationship was found relating the volume fraction of the micelles to NaDS concentration. 相似文献
10.
Two microbial cultures—ML-13 (aCandida sp.) and LSC (a fungal isolate from the University of Arkansas)—have been employed in the direct liquefaction of Louisiana
lignite. Lignite samples were pretreated with nitric acid and microbial culture broths at elevated temperatures and pressures.
Subsequent treatment with active cultures and culture derivatives resulted in significant solubilization of the lignite. Up
to 50% liquefaction of pretreated coal (20% HNO3 at ambient temperature and pressure) was observed in 4 d with ML-13 cultures, whereas almost 80% liquefaction occurred in
a similar time period when exposing pretreated lignite to an autoclaved, cell-free culture broth. 相似文献