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991.
Rasmussen TS Koldsø H Nakagawa S Kato A Schiøtt B Jensen HH 《Organic & biomolecular chemistry》2011,9(22):7807-7813
Inhibition of β-glucuronidases has recently been shown to be useful in alleviating drug toxicity for common colon cancer chemotherapeutic CPT-11 (also called Irinotecan). We have prepared a new compound of the nortropane-type, uronic-Noeurostegine, and demonstrated that this is a competitive and potent E. coli β-glucuronidase inhibitor, while inhibition of the mammalian β-glucuronidase from bovine liver was found to be less significant. Although not intended, two other compounds having N-ethyl and N-(4-hydroxybutyl) substituents were also prepared in this study due to the sluggish debenzylation in the final step. The N-substituents are believed to come from reaction with the solvents used being ethanol and THF, respectively. These compounds also inhibited the two β-glucuronidases albeit to a lesser extent compared to the parent compound. Noeurostegine and the three uronic-noeurostegines were additionally evaluated as inhibitors against a wide panel of glycosidases with the former showing potent inhibition of rat intestinal lactase and trehalase, whereas the latter was found to be inactive. 相似文献
992.
Kanie K Sekiguchi J Zeng X Ungar G Muramatsu A 《Chemical communications (Cambridge, England)》2011,47(24):6885-6887
Lyotropic liquid-crystalline phospholipids having an electro- and/or light-responsive mesogenic core were prepared. These LCs show lyotropic smectic A, smectic C, rectangular columnar, and nematic phases. We succeeded in the dynamic control of these LC phases by applying an electric field, which could lead to electrically switchable phospholipid bilayers. 相似文献
993.
Tran PL Moriyama R Maruyama A Rayner B Mergny JL 《Chemical communications (Cambridge, England)》2011,47(19):5437-5439
L-DNA, the mirror image of natural DNA forms structures of opposite chirality. We demonstrate here that a short guanine rich L-DNA strand forms a tetramolecular quadruplex with the same properties as a D-DNA strand of identical sequence, besides an inverted circular dichroism spectra. L- and D-strands self exclude when mixed together, showing that the controlled parallel self-assembly of different G-rich strands can be obtained through L-DNA use. 相似文献
994.
Poly(methyl methacrylate) grafted imogolite clay nanotubes were fabricated via activators regenerated by electron transfer for atom transfer radical polymerization (ARGET ATRP) by designing a water-soluble amphiphilic ATRP initiator that can adsorb onto imogolite surface in an aqueous solution. 相似文献
995.
Atsushi Suzuki Ryota Ishii Yoji Yamakami Ken Nakano 《Colloid and polymer science》2011,289(5-6):561-568
In this paper, we report the experimental results of surface friction between thermoresponsive poly(N-isopropylacrylamide) gels in water. The static friction force was found to depend on the waiting period prior to slider movement after contact between gel surfaces, which was a result of two relaxation mechanisms: the stress decay process due to macroscopic deformation under a normal load and the microscopic conformational change in the real contact area of polymer networks. The sliding velocity and the normal load dependence of the kinetic friction force were extensively measured. The results suggested that the following two mechanisms depended on the sliding velocity: the friction force generated by direct contact of the solid-like behavior and the viscous resistance of the liquid-like behavior. The strong temperature dependence of kinetic friction was observed, which was a result of a change in the balance between hydrophobic and hydrophilic interactions. The experimental results are discussed in terms of the multi-asperity contacts between the swollen gel/gel interfaces (solid friction, depending on the waiting period) and the viscous resistance and lubricating effect between the gel/water interfaces (fluid friction, depending on the sliding velocity). 相似文献
996.
We synthesized and characterized a new compound [{Dy(hfac)3}2Pd(dpk)2] ([Dy2Pd]; Hdpk = di-2-pyridyl ketoxime), which is isostructural with the known [Dy2Cu] and [Dy2Ni]. The study of the [Dy2Pd] compound containing diamagnetic Pd ion is indispensable to clarify a contribution of the exchange coupling for a 4f-3d single-molecule magnet behavior. From the ac susceptibility measurements on [Dy2Pd], we obtained Δ/kB = 28.6(11) K and TB = 1.1 K. In accordance with the blocking behavior, the pulsed-field magnetization showed the hysteresis behavior below 1.1 K. These parameters on [Dy2Pd] having SPd = 0 was compared with those of the derivatives having SCu = 1/2 (Δ/kB = 47 K and TB = 1.8 K) and SNi = 1 (Δ/kB = 62(4) K and TB = 2.5 K). The TB and Δ steadily increase with the increasing 3d(4d) spin quantum number. 相似文献
997.
Tanaka A Kamikubo H Kataoka M Hasegawa Y Kawai T 《Langmuir : the ACS journal of surfaces and colloids》2011,27(1):104-108
Size-controlled formation of colloidal aggregates composed of cube-shaped EuS nanocrystals, EuS NCs, in solution phase are reported and their optical and magneto-optical properties are studied. The average size of the colloidal particles of the EuS NCs-aggregates formed in 1-pentanol, 1-hexanol, and 1-octanol were ca. 800, 500, and 100 nm, respectively. Self-organized cubic-type superlattice structure was evaluated in the colloidal aggregates by means of the small-angle X-ray diffraction measurements, which is similar to those in the macroscopic 3D superlattice structures. The distances between NCs in the EuS NCs-aggregates are dependent on alkyl chain length of the solvent alcohol. Magneto-optic properties of EuS NCs-aggregates and the monomeric EuS nanocrystals in liquid media are characterized with magnetic circular dichroism spectra. The active wavelength of EuS NCs-aggregates is considerably longer than that of the monomeric EuS nanocrystals. 相似文献
998.
Nakashima Y Suzuki S Yamazaki M Inoue Y Fukatsu Y Yamamoto A 《Analytical sciences》2011,27(9):889-892
A quantitative analysis was developed for eight acidic and neutral preservatives in foods and daily necessities using the inline dialysis-IC combined with hydrophobic anion-exchange separation. The eight preservatives were dialyzed by inline dialysis and separated on a hydrophobic anion exchange column. Under the optimized separation conditions, the detection limits (S/N = 3) for the eight preservatives were from 0.08 to 0.66 mg L(-1), moreover, a good linearity (R(2) > 0.998) for each preservative was obtained in the range to 100 mg L(-1). Although the dialysis rate of the neutral preservatives was not so high, a good repeatability (RSD, n = 8) of less than 1.5% for the eight preservatives was obtained. The inline dialysis-IC method was applied to the determination of the preservatives in foods and daily necessities. The preservatives were quantified without any interference. The proposed method will be useful for the determination of the preservatives in foods and daily necessities containing high concentration matrices. 相似文献
999.
A novel hydrophilic stationary phase bonded with a zwitter-ionic polymer for HPLC was synthesized. The stationary phase, in combination with a mobile phase containing various salts, was evaluated for its ability to separate water-soluble compounds, such as nucleobases, nucleosides and glycosides. The retention of a large majority of the solutes, except for cytosine, was increased by adding anti-chaotropic ions to the mobile phase. These results suggested that the retention of solutes depended on the thickness of the hydration layer on the stationary phase. In the zwitter-ionic polymer adsorbent, the formation of the hydration layer and the ionicity of the zwitter-ionic group on the stationary phase will be controlled by the properties of the ions added to the mobile phase. 相似文献
1000.
Sagisaka M Iwama S Hasegawa S Yoshizawa A Mohamed A Cummings S Rogers SE Heenan RK Eastoe J 《Langmuir : the ACS journal of surfaces and colloids》2011,27(10):5772-5780
The fluorinated double-tailed glutarate anionic surfactant, sodium 1,5-bis[(1H,1H,2H,2H-perfluorodecyl)oxy]-1,5-dioxopentane-2-sulfonate (8FG(EO)(2)), was found to stabilize water-in-supercritical CO(2) microemulsions with high water-to-surfactant molar ratios (W(0)). Studies were carried out here to obtain detailed information on the phase stability and nanostructure of the microemulsions by using a high-pressure UV-vis dye probe and small-angle neutron scattering (SANS) measurements. The UV-vis spectra, with methyl orange as a reporter dye, indicated a maximum attainable W(0) of 60 at 45 and 75 °C, and SANS profiles indicated regular droplet swelling with a linear relationship between the water core nanodroplet radius and W(0). This represents the highest water solubilization reported to date for any water-in-CO(2) microemulsion. Further analysis of the SANS data indicated critical packing parameters for 8FG(EO)(2) at the microemulsion interface >1.34, representing approximately 1.1 times the value for common aerosol-OT in water-in-heptane microemulsions under equivalent conditions. 相似文献