Tuning saccharide selectivity in modular fluorescent sensors

Five modular photoinduced electron-transfer (PET) sensors bearing two phenylboronic acid receptors with different fluorophores have been prepared. The sensors’ interaction with saccharides was assessed via fluorescence spectroscopy. It was shown that monosaccharide selectivity is influenced by the choice of fluorescent moiety.     

Ueber die Beziehungen von Neutralsalz zu Säureeiweiß

Ohne Zusammenfassung     

Peroxidase-dependent fluorescence decrease of carboxyfluorescein and its enhancement by liposome encapsulation

The fluorescence intensity of 5(6)-carboxyfluorescein (CF) was decreased by addition of horseradish peroxidase (HRP) and hydrogen peroxide (H₂O₂). The reaction inside a liposome containing CF and HRP on addition of H₂O₂ was measured fluorometrically after destruction of the liposome with Triton X-100. The reaction efficiency was higher than that without liposome because CF and HRP were concentrated inside the latter. The determination of H₂O₂ can be performed with a smaller amount of HRP by liposome encapsulation.     

Inter-collisional cutting of multi-walled carbon nanotubes by high-speed agitation

High-speed agitation by a mixing blade has efficiently achieved the cutting of a large diameter (100-150 nm) of multi-walled carbon nanotubes. The cutting process is caused by an inter-collision of the nanotubes with high transfer energy. The collision-induced cutting allows for the shortening of the nanotubes without serious damage of the original graphitic layers due to the cutting effect being limited to the collision points. Furthermore, the operation under ambient atmosphere introduces oxygen-containing functional groups to the cut nanotubes. The estimated length distribution has indicated that high-speed agitation achieves a large cutting effect during a short duration of several minutes.     

A construction of simple Jordan superalgebra of F type from a Jordan–Lie triple system

We study in this paper a construction of simple Jordan superalgebras from certain triple systems, in particular, we investigate F type from a Jordan–Lie triple system minutely. Received: April 11, 2000; in final form: July 20, 2001?Published online: July 9, 2002     

A regioselective enolate formation of trimethylsilylmethyl ketones application to the (E)-selective synthesis of α,β-unsaturated ketones

Two possible enolate anions of trimethylsilylmethyl ketones have been prepared regioselectively by the appropriate choice of base. The one directed to the silylmethyl site behaves as a highly reactive and (E)-selective condensation reagent to aldehydes.     

Jellium-model calculation for monomer and dimer decays of some potassium clusters

We have studied several decay processes of potassium clusters and found that a dimer-decay mechanism can explain the observed lowest abundance of K₁₀ in the K _n mass spectra. Total-energy curves for decay processes are calculated using a jellium-background model for positive-ion cores and the local-spin-density-functional approximation for valence electrons. The energy-barrier height for a dimer decay of K₁₀ from the energy-minimum point is found to be 0.18 eV, which is a reasonable magnitude for the decay to take place thermally in the experiment. The monomer decay of K₉ and the dimer decay of K₁₁, which are expected to be the most favorable decays of K₉ and K₁₁, are found to have high barriers. Monomer and dimer decays of K₈ are also studied and the monomer decay is found to be more favorable, in accord with the high-nozzle-temperature mass spectrum.     

A regio- and stereo-controlled synthesis of α,β-unsaturated carbonyl compounds

α,β-Unsaturated carbonyl compounds and butenolides are readily prepared by the rhodium(I) catalyzed isomerization of 1,3-diene monoepoxides and α-alkylidene-γ-butyrolactones, respectively. The former transformation is formally regarded as the equivalent of a regiospecific aldol condensation of an unsymmetrical ketone.