A mesoporous membrane composed of nanochannels with a uniform diameter has a potential use for precise size-exclusive separation of molecules. Here, we report a novel method to form a hybrid membrane composed of silica-surfactant nanocomposite and a porous alumina membrane, by which size-selective transport of molecules across the membrane becomes possible. The nanocomposite formed inside each columnar alumina pore was an assembly of surfactant-templated silica-nanochannels with a channel diameter of 3.4 nm; the channel direction being predominantly oriented along the wall of the columnar alumina pore. Molecules could be transported across the membrane including the silica-surfactant nanocomposite with a capability of nanometre-order size-exclusive separation. Our proposed membrane system has a potential use not only for separation science, but also catalysis and chip technologies.

BackgroundFatty acid-binding protein 4 (FABP4/A-FABP/aP2), a lipid chaperone, is expressed in both adipocytes and macrophages. Recent studies have shown secretion of FABP4 from adipocytes and association of elevated serum FABP4 level with obesity, insulin resistance, and atherosclerosis. However, little is known about the role of FABP4 in essential hypertension.MethodsWe first examined serum FABP4 concentrations in 18 normotensives (NT) and 30 nontreated essential hypertensives (EHT). The EHT were divided into 18 insulin-sensitive EHT (EHT-S) and 12 insulin-resistant EHT (EHT-R) based on their insulin-sensitivity index, the M value, determined by the hyperinsulinemic–euglycemic clamp technique. In the second study, we determined FABP4 levels in 30 young NT men with or without a family history of hypertension (FH+ and FH–, respectively; n = 15 each).ResultsSerum FABP4 level was significantly higher in the EHT-R than in the NT, whereas elevation of FABP4 level in the EHT-S was not statistically significant. FABP4 level was positively correlated with age, body mass index (BMI), blood pressure, and triglycerides and negatively correlated with the M value. FABP4 level was an independent predictor of mean arterial pressure after adjustment of age, gender, and adiposity. The FH+ group had a significantly lower level of M value and higher level of FABP4 than did the FH– group, and FABP4 concentration was an independent determinant of the M value.ConclusionsFABP4 contributes to blood pressure elevation and atherogenic metabolic phenotype in hypertensives, and the elevation of FABP4 is predisposed by a family history of hypertension.

The local environments surrounding dye molecules were studied with use of coumarin dyes in a mesostructured silica-surfactant nanocomposite, which was formed in a porous alumina membrane by a surfactant-templated method and has an average pore diameter of 3.4 nm. Coumarin dyes, such as coumarin 480 (C480), coumarin 343 (C343), and propylamide coumarin 343 (PAC343), were extracted into the silica-surfactant nanocomposite and time-resolved fluorescence spectra of these dyes were examined. C480 and C343 show slow dynamic Stokes shifts and the decay curve can be fitted by a biexponential function. The decay-time constants obtained from the fitting are almost identical for C480 and C343: 0.87 and 7.5 ns for C480, and 0.86 and 7.6 ns for C343. In contrast to these two coumarin dyes, short decay-time constants (0.50 and 4.8 ns) were obtained for PAC343 in the silica-surfactant nanocomposite. These results indicate that the local environments of C480 and C343 are almost identical but different from that of PAC343. By considering the origin of the dynamic Stokes shift and the mesostructure of the silica-surfactant nanocomposite, the location and microenvironment of coumarin dyes within the silica-surfactant nanocomposite are discussed.

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