High birefringence photopolymerizable phenylacetylene liquid crystals

Photopolymerizable three-ring phenylacetylene (3PA) liquid crystalline compounds were synthesized and the physical properties of the monomers and polymers were characterized in the expectation of obtaining high birefringence polymers. 3PA monomers containing acrylate substituents exhibited enantiotropic nematic phases and high δn values of around 0.35. Homogeneous alignment was retained after polymerization and high values of δn (~0.34) for the polymers were obtained. The orientation of the monomers at the photopolymerization temperature was almost fixed, such that δn and the order parameter of the polymers varied with the polymerization temperature.     

Kinetic evaluation of the reactivity of flavonoids as radical scavengers

The reactivity of flavonoids as radical scavengers was investigated under kinetic considerations using radical polymerization of methyl methacrylates initiated by benzoyl peroxide. The number of radicals which are trapped by each molecule of phenol (the stoichiometric factors, n values) decreased in the order of epigallocatechin-3- O -gallate (ECG) (5.5) > catechin (3.5) > resveratrol (2.4) > quercetin (1.9)> n -propylgallate (1.5) > hesperetin (1.0). The inhibition rate constants ( k inh ) (1-3 ‐ 10 3 l/(mol s)) for the flavonoids were not different from each other, and, therefore, the radical scavenging activity depend on n values. The n values of the fully oxidized flavonoids were estimated from the frontier orbital theory, using PM3 semiempirical molecular orbital calculation. The experimental n values were consistent with the calculated values.     

Heavy fans, cycles and paths in weighted graphs of large connectivity

A set of paths joining a vertex y and a vertex set L is called (y,L)-fan if any two of the paths have only y in common, and its width is the number of paths forming it. In weighted graphs, it is known that the existence of heavy fan is useful to find a heavy cycle containing some specified vertices.In this paper, we show the existence of heavy fans with large width containing some specified vertices in weighted graphs of large connectivity, which is a weighted analogue of Perfect's theorem. Using this, in 3-connected weighted graphs, we can find heavy cycles containing three specified vertices, and also heavy paths joining two specified vertices containing two more specified vertices. These results extend the previous results in 2-connected weighted graphs to 3-connected weighted graphs.     

Measurement of the decay and time-resolved spectra of the emission from σ-excitons in KBr in the nanosecond range,produced by heavy-ion irradiation

While energetic heavy ions are currently in increasing use in solid state physics, radiation chemistry and biology, there is still little experimental information regarding the primary physicochemical processes. These high LET (linear energy transfer) ion particles injected into condensed matter produce short life-intermediates such as excited states, ions, and radicals, at high density along the track. The density effect of these intermediates may cause damage-formation and chemical reaction to yield different results compared with low LET radiation (γ, X-ray) or photo-irradiation. Electronically excited states, among the above intermediates, are thought to be especially important precursors. Measurements of the decay and time-resolved spectra of the emission are expected to give useful information regarding the radiation action of heavy ions. The measurements were done using a KBr single crystal at 4.2 K. We reported previously [1] that heavy ion irradiated KBr results in an extraordinarily large ratio of σ-emission to π-emission 2 intensity (～ 5 times larger than in the X- or electron-irradiation). This large ratio is, as was ascertained previously, not due to apparent processes such as temperature increase of a track but to intrinsic processes which will be discussed here.     

Sulfur-containing polymers. V. Preparation of polyoxycarbonylsulfenamides by polycondensation of bis(oxycarbonylsulfenyl chlorides) with diamines

Polyoxycarbonylsulfenamides (POSA) have been prepared by interfacial polycondensation of bis(oxycarbonylsulfenyl chlorides) with diamines. The polymers obtained ranged in physical form from crystalline solids to resinous materials depending on the kind of both bis(oxycarbonylsulfenyl chlorides) and diamines used. Some of the polymers gave transparent pliable films from chloroform solution. The polymer films decomposed with liberation of carbonyl sulfide on being subjected to ultraviolet radiation.     

A convenient method for the synthesis of (E)-3-alkenoic acids by a regio- and stereoselective reaction of β-vinyl-β-propiolactone with organocopper reagents

β-Vinyl-β-propiolactone reacts regio- and stereoselectively with Grignard reagents in the presence of copper(I) catalyst or with diorganocuprates to afford (E)-3-alkenoic acids in high yields.     

A novel five-carbon homologation leading to 3,4-alkadienoic acids by SN2′ reaction of β-ethynyl-β-propiolactone with grignard reagents in the presence of copper(i) catalyst

β-Ethynyl,-β-propiolactone reacts regioselectively with Grignard reagents in the presence of copper(I) catalyst to afford 3,4-alkadienoic acids in high yields. Synthetic utility of this reaction is demonstrated in the simple synthesis of pellitorine.     

Preparation of composite monoliths of quaternized chitosan and diatom earth for protein separation

In this study, composite monoliths with porous structures were prepared using quaternized chitosan and diatom earth for protein separation. Quaternized chitosan (N-[(2-hydroxy-3-trimethylammonium)propyl] chitosan chloride) dissolved in water was mixed with diatom earth and crosslinked with glutaraldehyde under low-temperature conditions to form a cryogel. Interconnected porous monoliths were obtained after removing ice crystals from the cryogel. The monoliths adsorbed bovine serum albumin selectively from the solution mixture of bovine serum albumin and bovine ɤ-globulin, and bovine ɤ-globulin was recovered in the flow-through fraction. The adsorption selectivity was enhanced by changing the solution pH from 6.8 to 5.5. The adsorption of bovine serum albumin by the monolith was replicated at least five times following its washing with a buffer containing 400 mM NaCl and subsequent regeneration with a 10 mM acetate buffer. The composited monolith is a promising adsorbent for the removal of acidic proteins, such as serum albumin contamination in neutral proteins, for example, ɤ-globulins, in bioproduction processes.