Rearrangement of indene skeletons under mild conditions

Isomerization between two isomers of 1,2-disubstituted 3-aminoindenes occurs via the rearrangement of indene frameworks. In contrast to previous rearrangements of indene derivatives, which occur under high-temperature conditions or the irradiation of light, this rearrangement proceeds at room temperature without UV light irradiation. An amino group at the 3-position plays an important role to accelerate the rearrangement under mild conditions.     

Facile synthesis of amine-terminated aromatic polyamide dendrimers via a divergent method

[structure: see text]. A novel, rapid, inexpensive, and highly efficient divergent approach for the synthesis of a 32-amine-terminated G4 polyamide dendrimer has been developed. Each generation dendrimer was successfully obtained by the condensation of the preceding generation dendrimer with the building block and the deprotection with hydrazine in one pot. All the dendrimers were easily purified by precipitation in alkaline water, and the purity was confirmed by NMR, MALDI-TOF mass spectra, and elemental analysis.     

Ionization of linear alcohols by strong optical fields

We have experimentally probed the strong-field ionization dynamics of gas-phase linear alcohols, methanol, ethanol, and 1-propanol, by irradiating them with intense, femtosecond-duration laser pulses of 800 and 400 nm wavelength. Specifically, we make high resolution measurements of the energies of electrons that are ionized by the action of the optical field. Our electron spectroscopy measurements enable us to bifurcate the dynamics into multiphoton ionization and tunneling ionization regimes. In the case of 800 nm irradiation, such bifurcation into different ionization regimes is reasonably rationalized within the framework of the adiabaticity parameter based on the original Keldysh-Faisal-Reiss model of atomic ionization, without recourse to any structure-dependent modifications to the theory. In that sense, our 800 nm spectroscopy indicates that the linear alcohols exhibit atom-like properties as far as strong field ionization dynamics in the multiphoton ionization and tunneling regimes are concerned. We also explore the limitations of this atom-like picture by making measurements with 400 nm photons wherein the ponderomotive potential experienced by the ionized electrons is much less than the photon energy; effects that are purely molecular then appear to influence the strong field dynamics.     

Free Self-decomposability and Unimodality of the Fuss–Catalan Distributions

Journal of Statistical Physics - We study properties of the Fuss–Catalan distributions $$\mu (p,r)$$, $$p\ge 1$$, $$01$$ there exists $$r_{0}(p)$$, with $$p-1     

Expression of a model peptide of a marine mussel adhesive protein in Escherichia coli and characterization of its structural and functional properties

An expression system for a chemically synthesized gene, encoding a model peptide of marine mussel adhesive protein, was constructed in Escherichia coli under regulation of the T7‐promoter. The model peptide consisted of six repeats of the decapeptide AKPSYPPTYK. Although the product was expressed as an inclusion body, we were able to solubilize it successfully, using acetic acid. The higher‐order structure of this model peptide was investigated using CD spectroscopy and NMR spectroscopy. Using the modified enzyme, mushroom tyrosinase, the tyrosine residue was hydroxylated to 3,4‐dihydoxyphenylalanine (Dopa), and the resulting modified peptide was polymerized, solidified, and insolubilized spontaneously. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 729–736, 1999     

Chemoselective synthesis of polyamides containing hydroxyl and amino substituents by direct polycondensation

A convenient method for the synthesis of polyamides containing hydroxyl and amino substituents on the aromatic rings of the backbones was developed. These polymers were prepared readily by the chemoselective polycondensation of dicarboxylic acids with diamines with hydroxyl and amino functional groups via the activating agent diphenyl(2,3‐dihydro‐2‐thioxo‐3‐bezoxazolyl)phosphonate. The model reactions were studied in detail to demonstrate the feasibility of chemoselective polycondensation. The direct polycondensation of 5‐hydroxy or 5‐aminoisophthalic acid with 4,4′‐diamino‐4″‐hydroxytriphenylmethane proceeded smoothly under mild conditions and produced the desired polyamides with inherent viscosities up to 0.73 dL · g⁻¹. The polymers obtained were characterized by IR, ¹H NMR, and ¹³C NMR spectroscopies. The polymers were readily soluble in aprotic polar solvents such as N‐methyl‐2‐pyrrolidinone, N,N‐dimethyl formamide, and dimethyl sulfoxide. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 3875–3882, 2000     

Fringe projection profilometry system verification for 3D shape measurement using virtual space of game engine

Optical Review - Fringe projection profilometry (FPP) is a technique used for obtaining the three-dimensional shape of an object in fields such as reverse engineering, cultural heritage, and...