Specific Adhesion of 3T3‐L1 Fibroblast onto Uridine‐Containing Polystyrene

A hydrophobic 96‐well multiplate was incubated with aqueous poly(uridine 5′‐p‐styrenesulfonate) (PUSS). Analysis of the PUSS‐coated surface indicated that the surface incubated at higher polymer concentration (50 mg·mL^–1) was hydrophilic while the surface incubated at lower polymer concentration (1 mg·mL^–1) was hydrophobic. Adhesion of 3T3‐L1, which has GalTase on the cell membrane, on the hydrophobic PUSS‐coated surface was greater than on the non‐coated surface. 3T3‐L1 adhesion on the hydrophilic PUSS‐coated surface was even greater. On the other hand, the adhesion of HeLa cells, which did not show GalTase on the cell membrane, on the hydrophilic surface was quite weak. It may well be said that the 3T3‐L1 adhesion on the hydrophilic PUSS‐coated surface was GalTase‐mediated.     

Synthesis and polymerization of chiral methacrylates bearing a cholesteryl or menthyl group

Chiral methacrylates, that is, cholesteryl (ChMOC) and l‐menthyl (MnMOC) N‐(2‐methacryloyloxyethyl)carbamates, were synthesized from 2‐methacryloyloxyethyl isocyanate and cholesterol and l‐menthol, respectively. Radical polymerizations of ChMOC and MnMOC gave number‐average molecular weights for poly(ChMOC) and poly(MnMOC) of up to 3.74 × 10⁴ and 9.39 × 10⁴, respectively, and the specific rotations ([α]) were −43.1° to −47.7° and −87.6° to −89.0°, respectively. Temperature dependence of the specific optical rotation was observed for poly(ChMOC) but not for poly(MnMOC). The hydrogen bonds based on urethane segments for poly(ChMOC) were stronger than those for poly(MnMOC) according to IR spectra. In addition, the chiroptical properties of poly(ChMOC) were slightly affected by temperature in the presence of trifluoroacetic acid acting as an inhibitor for the formation of hydrogen bonds. Therefore, poly(ChMOC) may have a regular conformation due to hydrogen bonds and interaction between cholesteryl groups. Radical copolymerizations of ChMOC with styrene, methyl methacrylate, N‐cyclohexylmaleimide, and N‐phenylmaleimide were performed with 2,2′‐azobisisobutyronitrile in tetrahydrofuran at 60 °C. Monomer reactivity ratios and Alfrey–Price Q–e were determined. Chiroptical properties of the copolymers were influenced by co‐units. Thermal and X‐ray diffraction analyses were performed for the homopolymers and copolymers. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 4315–4325, 2000     

Conversion of Molecular Oxygen into a Hydroperoxo Species by Ring-Opening Protonation of a Cyclic η2-Peroxo Intermediate: Characterization of the η2-Peroxo and Hydroperoxo Complexes

A transition metal–hydroperoxo species is formed by the oxygenation of a low-valent rhodium precursor followed by a protonation of the resulting η²-O₂ ligand; the latter process is assisted by an intramolecular hydrogen-bonding interaction (see scheme). This process is the first structural evidence for an effective method for the activation of molecular oxygen as postulated for the cytochrome P-450 system.     

Syntheses and thermostabilities of N-[4-(N′-substituted aminocarbonyl)phenyl]maleimide polymers

Three types of novel N-[4-(N′-substituted aminocarbonyl)phenyl] maleimide (RPhMI: N-substituent (R) = phenyl, cyclohexyl, and cyclododecyl) were synthesized and homopolymerized under several conditions. In the copolymerizations of RPhMI (M₁) with styrene (ST; M₂) or methyl methacrylate (MMA; M₂), monomer reactivity ratios and Alfrey-Price Q, e values were determined. All homopolymers decomposed without softening and melting points. The initial degradation temperatures (T_d) of poly(RPhMI)s were over 320°C. The glass transition temperatures (T_g) of RPhMI copolymers were much higher than those of N-phenylmaleimide (PhMI)–ST, PhMI–MMA, N-cyclohexylmaleimide (CHMI)–ST, and CHMI–MMA copolymers. Thermal stability of the terpolymers of RPhMI with ST and acrylonitrile (AN) was higher than that of ST–AN copolymers, i.e., AS resin. © 1998 John Wiley & Sons, Inc. J. Polym. Sci. A Polym. Chem. 36: 2001–2012, 1998     

SEM Observation of Nucleation and Growth of Ag Crystallites on Graphite Substrate

“In-Situ” observation of nucleation and growth of Ag crystallites on graphite substrate by vapour deposition was carried out by scanning electron microscope (SEM). Irradiation of the SEM electron beam onto the substrate surface before and during deposition enhanced Ag nucleation. The density of the Ag crystallites was 10¹⁰/cm² in room temperature condensation, but decreased to 10⁹/cm² in high temperature condensation at 140 °C. When the substrate was heated after room temperature condensation, the density of the Ag crystallites decreased prominently. This means that coalescence of the Ag crystallites takes place as a result of their migration on the substrate.     

Poly(phenylhydrosilane): Base-developable polysilane resist

Poly(phenylhydrosilane) becomes soluble in a 2.38% tetramethylammoniumhydroxide aqueous solution after exposure to UV light. This is the first report that the polysilanes not bearing acidic groups can be developed with dilute basic aqueous solutions. Addition of 3,3′,4,4′-tetra(t-butylperoxycarbonyl)benzophenone increases the resist sensitivity. The reaction mechanism is as follows: PS1 photodecomposes to form silyl compounds having SiOH groups, which become soluble in an aqueous base solution, because these silane compounds bearing SiOHs are acidic. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35 : 2355–2364, 1997     

Simultaneous biobehavior of trace elements, Sc, Mn, Fe, Co, Zn, Se, Rb and Zr in the brain and other organs of C57BL/6N mice

The radioactive multitracer technique was applied to a study on the uptake of trace elements in normal C57BL/6N mice. Comparative uptake behavior of⁴⁶Sc,⁵⁴Mn,⁵⁹Fe,⁵⁸Co,⁶⁵Se,⁸³Rb and⁸⁸Zr tracers was examined among 11 organs (brain, cardiac muscle, lung, liver, spleen, pancreas, kidneys, bone, muscle, eyeballs and testes) and blood, and evaluated in terms of the “tissue uptake rate (the radioactivity percentage of injected dose per gram of tissue, %dose/g)”. The multitracer technique revealed reliable data demonstrating characteristic uptake of the 8 trace elements, Sc, Mn, Fe, Co, Zn, Se, Rb and Zr by the brain and other organs, as well as the distinctive features of the accumulation and retention of each element in the brain.     

Structure of stoichiometric USi2

Stoichiometric USi_2.00±0.05 which was thought to be “ord USi_1.88” so far was prepared by immersing USi_1.88 in 1:1 HCl solution, which led to a selective dissolution of excess uranium into the acid. The uranium disilicide thus prepared has two-dimensional platy shapes and tends to align its tetragonal basal planes (00l) parallel to the plane of the sample holder for X-ray diffraction. The orientation effects made it impossible to apply the standard powder pattern technique for the structure analysis of USi₂. The difficulty, however, was eliminated with the aid of a texture pattern technique which has been developed with X-ray diffraction.The uranium disilicide is of the ThSi₂ type ($\text{I4}{}_1\text{amd}$) with a = 3.922 ± 0.001 Å and c = 14.154 ± 0.002 Å, and z = 0.410 ± 0.002. A structural configuration of the compound is essentially the same as that of USi_1.88, except that it has no deficiency of Si.