Effect of Photoinduced Size Changes on Protein Refolding and Transport Abilities of Soft Nanotubes

Self‐assembly of azobenzene‐modified amphiphiles (Gly_nAzo, n=1–3) in water at room temperature in the presence of a protein produced nanotubes with the protein encapsulated in the channels. The Gly₂Azo nanotubes (7 nm internal diameter [i.d.]) promoted refolding of some encapsulated proteins, whereas the Gly₃Azo nanotubes (13 nm i.d.) promoted protein aggregation. Although the 20 nm i.d. channels of the Gly₁Azo nanotubes were too large to influence the encapsulated proteins, narrowing of the i.d. to 1 nm by trans‐to‐cis photoisomerization of the azobenzene units of the Gly₁Azo monomers packed in the solid bilayer membranes led to a squeezing out of the proteins into the bulk solution and simultaneously enhanced their refolding ratios. In contrast, photoinduced transformation of the Gly₂Azo nanotubes to short nanorings (<40 nm) with a large i.d. (28 nm) provided no further refolding assistance. We thus demonstrate that pertubation by the solid bilayer membrane wall of the nanotubes is important to accelerate refolding of the denatured proteins during their transport in the narrow nanotube channels.     

Constructions for anti‐mitre Steiner triple systems

In this paper, we present a recursive construction for anti‐mitre Steiner triple systems. Furthermore, we present another construction of anti‐mitre STSs by utilizing 5‐sparse ones. © 2004 Wiley Periodicals, Inc.     

Polymerizable Tautomers. VII. Radical Copolymerization of Ethyl 3-oxo-4-Pentenoate and Ethyl 4-Methyl-3-oxo-4-Pentenoate with Methyl Methacrylate

Abstract

Ethyl 3-oxo-4-pentenoate (EAA) and ethyl 4-methyl-3-oxo-4-pentenoate (EMAA) exhibit the coexistence of the ketonic and enolic forms in most organic solvents. Radical copolymerizations of EAA and EMAA with methyl methacrylate (MMA) were carried out at 60 °C in various solvents, and monomer reactivity ratios were estimated. There are minor solvent effects on monomer reactivity ratios r_MMA in both EAA/MAA and EM A A/MM A systems. On the other hand, r_EAA and r_MMA values greatly change with the solvent: The values decrease with an increase in the ketonic fraction of the polymerizable tautomers (EAA and EMAA). Regression analysis of the monomer reactivity ratios with the solvatochromic parameters reveals that polarity of the solvent is the major factor governing the relative reactivity.     

Shape modeling of mineral dust particles for light-scattering calculations using the spatial Poisson-Voronoi tessellation

We present a shape model of mineral dust particles for use in light-scattering calculations. A spatial Poisson-Voronoi tessellation was applied to simulate the aggregate structure and, therefore, the rough surface of the mineral particles. To develop the shape model, we took into account statistics of shape parameters derived from the cross-sectional areas, maximum dimensions, and perimeters of field-collected dust particles. Light-scattering properties of the modeled Voronoi aggregates were examined by the finite-difference time-domain (FDTD) method. The results of randomly oriented scattering properties agreed with previously reported laboratory measurements of mineral dust particles.     

Classification of minimal actions of a compact Kac algebra with amenable dual on injective factors of type III

We classify a certain class of minimal actions of a compact Kac algebra with amenable dual on injective factors of type III. The structural analysis of type III factors and the canonical extension of endomorphisms introduced by Izumi are our main technical tools.     

Stereoselective approach to potential scaffold of A-nor B-aromatic OSW-1 analogues via [4+2] cycloaddition of o-quinodimethane

A-nor B-aromatic steroidal skeleton was efficiently constructed by means of o-quinodimethane chemistry with exclusive stereoselectivity. The benzocyclobutene substrate for generation of the o-quinodimethane intermediate and subsequent [4+2] cycloaddition could be synthesized via (E)-selective Julia–Kocienski olefination and diastereoselective Grignard addition reactions. The synthesized tricyclic steroid-like compound with a trans-diol substructure would be utilized for divergent syntheses of potentially antitumor OSW-1 analogues with the truncated steroidal aglycone.     

3-(2-Pyridyl)-2-pyrazoline derivatives: novel fluorescent probes for Zn ion

Spectroscopic studies revealed that 3-(2-pyridyl)-2-pyrazoline derivatives have rather strong affinity toward divalent transition metal ions, but have almost no interaction with alkali and alkaline-earth metal ions. In the case of the 5-(4-cyanophenyl) derivative, enhancement of the fluorescence intensity was observed upon addition of the Zn²⁺ ion, while most of other transition metal ions caused complete quenching.