Materials Literature
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A new method of protein crystallization, the floating-drop vapour-diffusion technique, has been developed. The method combines the traditional sitting-drop vapour-diffusion technique and a novel two-liquid system. A crystallization drop composed of a mixture of sample and reagent floats on an insoluble and very dense…
A three-way model catalyst has been prepared with 0.58 wt % Pt on Ce 0.68 Zr 0.32 O 2 mixed oxide washcoated on a ceramic monolith. Conditions of the washcoating procedure, i.e., powder size distribution and acidic nature of the slurry, have been optimized. The activity on simultaneous elimination of NO, C 3 H 6, and…
A series of perfluoroalkyl end-capped poly(ethylene oxide) (PEO) of molecular weight M n = 10 000 and 20 000, noted F-HEUR-10K and F-HEUR-20K, with a well-defined structure were synthesized in two reaction steps. The reaction of PEO with a large excess of isophorone diisocyanate (IPDI) leads to an isocyanate-terminate…
A novel liquid crystalline quaternary five-block molecule is reported which is composed of four incompatible molecular parts, a rigid biphenyl core, two polar 2,3-dihydroxypropoxy groups in the terminal 4- and 4'-positions, and a branched semiperfluorinated chain in the lateral 3-position, consisting of a perfluorinat…
Layer-by-layer (LBL) films of a semiconducting polymer (POMA) alternated with a polyelectrolyte (PVS), adsorbed onto silicon oxide, mica, ITO/glass, Au/Cr/glass, hydrophilic and hydrophobic glass were studied by atomic force microscopy (AFM). The samples were characterized LBL with the AFM operating in the contact, fr…
Abstract Liquid propylene was polymerized in a 5‐L autoclave batch reactor using a commercially available TiCl 4 /MgCl 2 /Al(ethyl) 3 /DCPDMS Ziegler–Natta catalyst, with a phthalate ester as internal electron donor. The powders from these polymerizations were characterized using laser diffraction particle size distri…
Abstract Molecular distortion of a photoexcited diplatinum(II) complex in a single crystal has been directly observed by accurate synchrotron radiation diffraction studies. Photoexcited crystallographic analysis has revealed that a small portion of [Pt2(pop)4]4− (pop = H2O5P22−) complex shows the Pt–Pt bond shrinkage…
Abstract In a previous investigation, we observed that in the presence of a conventional vulcanization system, the addition of white rice husk ash (WRHA) to natural rubber (NR) compounds increased the rate of crosslinking and lowered the apparent activation energy ( E a ) of the vulcanization reaction more strongly th…
Yeast hypothetical protein YBL036C (SWISS-PROT P38197), initially thought to be a member of an 11-protein family, was selected for crystal structure determination since no structural or functional information was available. The structure has been determined independently by MIR and MAD methods to 2.0 A resolution. The…
Designed coiled-coil heterotrimers are described whose assembly is governed by both hydrophobic and hydrophilic forces. Sterically matched hydrophobic core side-chain packing of alanine and cyclohexylalanine has been shown to promote formation of a 1:1:1 heterotrimer. Manipulation of hydrophilic glutamic acid (Glu)/ly…
The adsorption and intercalation of the cationic luminescence probe, tris(2,2‘-bipyridine)ruthenium(II) complex ([Ru(bpy) 3 ] 2+ or Rubpy), into hectorite and Laponite host clay films were investigated. Because the photophysical properties of Rubpy are strongly influenced by the lamellar nanospace of the smectite host…
The electric conductance of the graphite ribbon with locally applied gate voltage has been studied in terms of the Landauer approach. In the low-energy region, nano-graphite ribbon with zigzag boundaries exhibits the single electronic transport channel due to the edge states. The chemical potential dependence of the e…
A new synthesis procedure has been developed for a series of maleimide-based fluorophores, exhibiting a large variation of emission spectra spanning the entire visible range.
The information depth (ID) is a measure of the sampling depth for the detected signal in Auger-electron spectroscopy (AES) and x-ray photoelectron spectroscopy (XPS) while the mean escape depth (MED) is a measure of surface sensitivity. We report ID and MED calculations for Si 2s, Si 2p3/2, Cu 2s, Cu 2p3/2, Au 4s, and…
The proper assignment of metal ions in X-ray structures of proteins is not always easy, but in many cases this knowledge can be important, e.g. for an understanding of enzyme mechanism. In this publication, the bond-valence approach is assessed critically. A simplified version, the calcium bond-valence sum (CBVS), is…
Abstract Propagation in the cationic ring‐opening polymerization of cyclic ethers involves nucleophilic attack of oxygen atoms from the monomer molecules on the cationic growing species (oxonium ions). Such a mechanism is known as the active chain‐end mechanism. If hydroxyl groups containing compounds are present in t…
Mesoporous silicas of the MSU-X type, made with nonionic polyethylenoxide-based (PEO) surfactants, were synthesized according to a two-step process that gives intermediary stable hybrid micelles. The influence of the various synthesis parameters, such as the silica concentration, the addition of a swelling agent (TMB:…
Percolation of particle arrays is of high interest in microstructural design of materials. While there have been numerous contributions to theoretical modeling of percolation in particulate systems, no analytical approximation for the generalized problem of variable aspect-ratio ellipses has been reported. In the pres…
A nonlinear thermodynamic theory is used to describe the influence of an external mechanical loading on the ferroelectric, dielectric, and piezoelectric properties of epitaxial thin films grown on dissimilar cubic substrates. The calculations are performed for single-domain perovskite films in the approximation of a h…
An algorithm is described for automated building of side chains in an electron-density map once a main-chain model is built and for alignment of the protein sequence to the map. The procedure is based on a comparison of electron density at the expected side-chain positions with electron-density templates. The template…