Materials Literature
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Nine crystal structures of free-base 5,15-diarylporphyrin derivatives are reported, and systematic analysis is made of the molecular conformations and intermolecular interactions in these and other comparable structures. In all cases, the porphyrins show minimal out-of-plane distortion in the solid state, but signific…
End product application is an important consideration when evaluating a material in an in vivo setting (Didisheim, Cardiovasc Pathol 1993;2:1S-2S). Small animal models allow high through-put evaluation of biocompatability. Previous preclinical evaluations have often used a rat subcutaneous model for the characterizati…
Abstract The P(O)‐H in 9,10‐dihydro‐oxa‐10‐phosphaphenanthrene‐10‐oxide (DOPO) was used as an active group to react with the carbonyl group in 4,4′‐dihydroxybenzophenone (DHBP) to result a novel phosphorous‐containing biphenol compound (DOPO‐2OH). Phosphorous‐containing epoxy resins were therefore obtained from react…
Abstract Permanent surface modification of polypropylene and high‐density polyethylene was obtained by blending with small (0.1 to 5.0% by weight) amounts of silicone copolymers. A triblock polycaprolactone‐ b ‐polydimethylsiloxane copolymer and a multiblock polydimethylsiloxane–urea copolymer were used as modifiers.…
Abstract 1 H and 13 C NMR spectroscopy of a series of 1‐vinyl‐2‐(2′‐heteroaryl)‐pyrroles were employed for the analysis of their electronic and spatial structure. The C—H···N intramolecular interaction between the α‐hydrogen of the vinyl group and the pyridine nitrogen, a kind of hydrogen bonding, was detected in 1‐vi…
Abstract In the presence of anhydrous ferric chloride as a Friedel–Crafts catalyst, the postcrosslinking reaction of macroporous styrene–divinylbenzene (St–DVB) copolymers synthesized under different conditions was carried out with 1,2‐dichloroethane as a solvent. Without an externally added crosslinking agent, the sp…
To facilitate tissue integration with biomaterials proteins and peptides frequently are immobilized on the biomaterial surface. In particular, extracellular matrix proteins--which interact specifically with integrin adhesion receptors on the cell surface--can stimulate initial cell attachment by serving both as a liga…
Photochromism of indolinospironaphthooxazine (SNO) microcrystalline powder was investigated by steady state and time-resolved diffuse reflectance spectroscopy using a femtosecond laser as a light source. When laser intensity is weak, the photoinduced ring-opening reaction in a picosecond time region and subsequent the…
The degradation of phthalic acid esters in an aqueous solution by sonochemical action was performed at an ultrasonic frequency of 200 kHz. The sonochemical degradation of phthalic acid esters followed pseudo first-order kinetics. The OH radical reaction was found to be a predominant factor of the degradation of diethy…
The reaction of methylviologen iodide with crystalline V2O5 in the molar ratio of 1 to 3.8 at 100 degrees C in water led to the formation of (MV)0.25V2O5 in quantitative yield. The structure of this organic-inorganic multilayered hybrid compound was determined by single-crystal X-ray crystallography. Strong van der Wa…
Heat capacity of the halogen-bridged mixed-valence complex Pt 2 (dta) 4 I (dta = CH 3 CS 2 - ) has been measured in the temperature region between 6 and 386 K. The complex exhibited a phase transition of order−disorder type at T trs = 373.4 K, from being arranged in an ordered helical form of four dta ligand planes ar…
For a given group-subgroup transition, the complete set of order parameters, primary and secondary, describe the distortions that accompany this transition. The task of obtaining all order-parametric distortions for a group-subgroup pair is a long standing problem. An algorithm is presented here which obtains the irre…
Abstract A thermosetting resin system for resin‐transfer molding based on novolak and bismaleimide (BMI) was developed. The novolak resin was allylated and BMI was used as the curing agent, and allyl phenyl ether, as the diluent. The viscosity–temperature curve and the viscosity–time curve were used to characterize th…
We compare the swelling of surface-attached neutral poly(4-vinylpyridine) (PVP) and charged poly( N -methyl-4-vinylpyridinium iodide) (MePVP) brushes under good solvent conditions using multiple-angle null ellipsometry. The polymer layers were prepared by the “grafting from” technique, where a low molecular mass initi…
We report electron paramagnetic resonance measurements on single crystalline and powder samples of ${\mathrm{Nd}}_{0.5}{\mathrm{Ca}}_{0.5}{\mathrm{MnO}}_{3}$ across the charge-ordering transition at ${T}_{\mathrm{co}}=240\mathrm{K}$ down to the antiferromagnetic ordering transition at ${T}_{N}=140\mathrm{K}.$ The chan…
We have developed a route for the synthesis of 2'-selenium uridine analogues and oligonucleotides containing selenium labels, and have demonstrated for the first time a new strategy to covalently derivatize nucleotides with selenium for phase and structure determination in X-ray crystallography.
A large scale synthesis of carbon nanofibers with a controlled diameter of about 50 nm has been achieved at relatively low temperatures (550–650 °C) by the decomposition of ethane on a carbon nanotube supported nickel catalyst. The carbon nanofibers can be used as a catalyst or a catalyst support without subsequent pu…
Recently, polymer–clay hybrid materials have received considerable attention from both a fundamental research and application point of view.1–3 This organic–inorganic hybrid, which contains a nanoscale dispersion of the layered silicates, is a material with greatly improved physical and mechanical characteristics. The…
Photocyclization and photocycloreversion quantum yields of three diarylethene derivatives were determined in the single-crystalline phase. The former yields in the crystalline phase were twice as large as those in solution. This can be attributed to only photoreactive antiparallel conformers being packed in the crysta…
Using state of the art time-dependent density functional theory and multireference second-order perturbation theory, we have accurately calculated (within 0.3 eV) in real space the optical gap of small silicon quantum dots, with diameters up to 25 A. Our results, which support the quantum confinement hypothesis, are i…