Arylethynyl Groups That Modulate Anion-Binding and Assembling Modes of Rod- and Fan-Shaped π-Electronic Systems

The introduction of arylethynyl moieties at the pyrrole α- and β-positions of dipyrrolyldiketone BF₂ complexes as anion-responsive π-electronic molecules was investigated. The arylethynyl-substituted derivatives formed a variety of anion complexes with planar [1+1]- and interlocked [2+1]-type structures in solution and in the solid state. The derivatives with long alkyl chains in the introduced arylethynyl groups also formed mesophases in the form of ion pairs of the anion complexes and a counter cation. The geometries of the constituent anion complexes affected the packing modes of the dimension-controlled assemblies.     

5+1] cycloaddition of C,N-cyclic N'-acyl azomethine imines with isocyanides

A catalyst-free [5 + 1] cycloaddition reaction between isocyanides and C,N-cyclic N'-acyl azomethine imines as the "isocyanophile" leading to novel heterocycles has been developed. These reactions proceeded quickly and cleanly to afford the corresponding imin-1,3,4-oxadiazin-6-one derivatives in high to excellent yields. A wide range of C,N-cyclic N'-acyl azomethine imines and isocyanides were applicable to this reaction.     

Adamantyl-functionalized polymer monolith for capillary electrochromatography

An adamantyl (ADM)-functionalized monolithic stationary phase was newly synthesized by a single-step copolymerization of 1-adamantyl-(α-trifluoromethyl) acrylate, ethylene dimethacrylate, and 2-acrylamido-2-methyl-1-propanesulfonic acid in order to prevent the peak tailing of basic solutes in capillary electrochromatography and was compared with butyl methacrylate (BMA)-based one. The ADM structure shields the negatively charged groups on the surface of monolith from basic solutes, resulting in better peak shapes than BMA-based monolithic stationary phase. As the monomers ratio decreased, the monolithic column had lower retention and higher column efficiency which was likely due to lower phase ratio and smaller globule size of monolith, respectively. The ADM-functionalized monolithic columns exhibited a good repeatability and reproducibility of column preparation with relative standard deviation values below 9% in the studied chromatographic parameters.     

Synthesis of an oligosaccharide–polylysine dendrimer with reducing sugar terminals leading to acquired immunodeficiency syndrome vaccine preparation

A novel cellobiose–polylysine dendrimer with reducing sugar terminals was synthesized in which the reactive reducing end of a disaccharide cellobiose was directing outward. Hexa‐O‐benzyl‐4′‐(1‐carboxyethyl)‐cellobioside (HBCEC) was synthesized through the reaction of a 4′‐hydroxyl group of benzyl hexa‐O‐benzyl‐cellobioside with methyl 2‐chloropropionate, followed by the removal of the methyl ester group. HBCEC was reacted with polylysine dendrimer generation 3 (G3) to produce benzylated cellobiose–polylysine dendrimer G3. After debenzylation, a cellobiose–polylysine dendrimer G3 was obtained in which the reducing end of the cellobiose was the terminal group of the dendrimer. For the preparation of a dendrimer‐type acquired immunodeficiency syndrome vaccine, the cellobiose–polylysine dendrimer was reacted with a tripeptide (glycyl–prolyl–leucine) and a cyclic oligopeptide from the human immunodeficiency virus by reductive amination; this produced a tripeptide‐bound cellobiose–polylysine dendrimer and an insoluble compound, respectively. The structure analysis was carried out with NMR and matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 2195–2206, 2005     

Emulsifying Ability of β-Cyclodextrins for Common Oils

Emulsification of various common oils was investigated using natural β-cyclodextrin (β-CD) and its derivatives as emulsifiers. An oil/water (O/W) emulsion was formed using β-CD, whereas a water/oil (W/O) emulsion was formed using tripropanoyl-β-CD and tributanoyl-β-CD derivatives. Triacetyl-β-CD gave rise to both O/W and W/O emulsions. The type of emulsion was governed by the contact angle (θ_ow), which the precipitate of CD origin make with the oil-water interface.     

An empirical study on similarity-based mating for evolutionary multiobjective combinatorial optimization

We have already proposed a similarity-based mating scheme to recombine extreme and similar parents for evolutionary multiobjective optimization. In this paper, we examine the effect of the similarity-based mating scheme on the performance of evolutionary multiobjective optimization (EMO) algorithms. First we examine which is better between recombining similar or dissimilar parents. Next we examine the effect of biasing selection probabilities toward extreme solutions that are dissimilar from other solutions in each population. Then we examine the effect of dynamically changing the strength of this bias during the execution of EMO algorithms. Computational experiments are performed on a wide variety of test problems for multiobjective combinatorial optimization. Experimental results show that the performance of EMO algorithms can be improved by the similarity-based mating scheme for many test problems.     

Carboxyfluorescein leakage from poly(ethylene glycol)-grafted liposomes induced by the interaction with serum

The effects of fetal bovine serum (FBS) on carboxyfluorescein (CF) leakage from poly(ethylene glycol)-grafted liposomes (PEG-liposomes) were investigated. PEG-liposomes were prepared from dipalmitoylphosphatidylcholine (DPPC) and distearoyl-N-monomethoxy poly(ethylene glycol)-succinyl-phosphatidylethanolamines (DSPE-PEG) having PEG molecular weights of 1000, 2000, 3000 and 5000. The presence of FBS dramatically increased CF leakage from liposomes near the gel-liquid crystalline phase transition temperature, but had little effect at lower and higher temperatures. The CF leakage from PEG-liposomes whose molecular weight in PEG units was above 2000 was suppressed compared with that of liposomes without PEG. And, there was hardly any difference in the effect of the PEG molecular weight of the PEG-lipids on CF leakage from PEG-liposomes with FBS when PEG-lipids with a molecular weight in PEG units above 2000 were used. On the other hand, the leakage of CF from liposomes containing 0.145 mol fractions of DSPE-PEG1000 was larger than that of liposomes without PEG. Furthermore, the effects of FBS on the cooperative units of lipid molecules during the gel-liquid crystalline phase transition of liposomes were examined. However, the cooperative units of liposomes with FBS had little change compared with that of liposomes without FBS.     

Determination of halofantrine and its main metabolite desbutylhalofantrine in rat plasma by high-performance liquid chromatography with on-line UV irradiation and peroxyoxalate chemiluminescence detection

A sensitive, selective and reliable method has been developed and validated for the determination of halofantrine and its metabolite desbutylhalofantrine in rat plasma using 9,10-diphenylanthracene as an internal standard. The method is based on peroxyoxalate chemiluminescence detection of hydrogen peroxide produced from fused aromatic rings in the structures of halofantrine and desbutylhalofantrine upon UV irradiation. Using spiked rat plasma, good linear relationships were obtained for both halofantrine and desbutylhalofantrine between peak height ratios (vs internal standard) and their corresponding concentrations over a range of 0.01-0.8 microg/mL with correlation coefficients of at least 0.997. The detection limits at signal-to-noise ratio of 3 using 0.2 mL of rat plasma were 1.5 and 1.4 ng/mL for halofantrine and desbutylhalofantrine, respectively. Relative standard deviations (n = 3) intra- and inter-day were between 0.5 and 5.4% for all the studied concentrations. Using this method with simple sample treatment, halofantrine and desbutylhalofantrine in rat plasma could be precisely determined without interference from endogenous substances. The method was successfully applied to the measurement of the time courses of plasma halofantrine concentration after oral administration of the drug (7 mg/kg) to rats.     

Highly viscoelastic reverse worm-like micelles formed in a lecithin/urea/oil system

While lecithin alone can form spherical or ellipsoidal reverse micelles in oil, we found that urea can promote the growth of lecithin reverse worm-like micelles in oil. In a mixed system of urea and lecithin, the urea binds to the phosphate group of lecithin, thus reducing the interface curvature of the molecular assembly and inducing the formation of reverse worm-like micelles. The regions in which these micelles form increased with lecithin concentration. In addition, the zero-shear viscosity (η ₀) of the reverse worm-like micelles rapidly increased upon the addition of urea, reaching a maximum of 2 million times the viscosity of n-decane. We examined the change in η ₀ in detail by performing dynamic viscoelasticity measurements. Values for η ₀ increased with urea concentration because the disentanglement time of reverse worm-like micelles increased with micellar growth.