Materials Literature
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ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTPronounced Axial Thiolate Ligand Effect on the Reactivity of High-Valent Oxo−Iron Porphyrin IntermediateYasuteru Urano, Tsunehiko Higuchi, Masaaki Hirobe, and Tetsuo NaganoView Author Information Graduate School of Pharmaceutical Sciences The University of Tokyo 7-3-1…
Quantitative x-ray-diffraction measurements in a temperature range 88--325 K were performed on porosity-free nanocrystalline (nc) elemental Se samples with a hcp structure. The nc-Se samples with different grain sizes were synthesized by crystallizing a melt-quenched amorphous-Se solid. Thermal-expansion coefficients…
In the present communication we demonstrate the synthesis of a hybrid block copolymer based on the combination of a biopolymer (amylose) with a synthetic block (polystyrene). To obtain such materials, amino-functionalized polymers were modified with maltoheptaose moieties that serve as initiators for the enzymatic pol…
Density functional calculations have been carried out on free-base porphyrin ( 1 ) and its seven possible isomers ( 2 − 8 ) with an N 4 -metal coordination core. A total of 27 structures resulting from geometrical isomerism (( E / Z )-configurations) and NH tautomerism were studied. Geometries were fully optimized wit…
Collagens contain a high amount of charged residues involved in triple-helix stability, fibril formation, and ligand binding. The contribution of charged residues to stability was analyzed utilizing a host-guest peptide system with a single Gly-X-Y triplet embedded within Ac(Gly-Pro-Hyp)3-Gly-X-Y-(Gly-Pro-Hyp)4-Gly-Gl…
Water present in a ligand binding site of a protein has been recognized to play a major role in ligand-protein interactions. To date, rational drug design techniques do not usually incorporate the effect of these water molecules into the design strategy. This work represents a new strategy for including water molecule…
A new method for analysing antiphase domains using high-resolution electron micrographs is described. A high-resolution electron microscope image taken at a zone axis is treated as the sum of many sets of interference fringes. The analysis extracts the information concerning the variations in the image periodicities a…
Ba 1− x Sr x TiO 3 (BST, x = 0 to x = 1) ferroelectric ceramics doped with 1.0 mol% MgO and 0.05 mol% MnO 2 were prepared with a rate‐controlled sintering profile. As the strontium molar fraction x increased, the average grain size decreased from 14 μm for x = 0 to 2 μm for x = 1. Temperature dependence of the dielect…
ABSTRACT Autolysis kinetics in axenic cultures of the diatom Ditylum brightwellii (West) Grunow were studied under nutrient limitation in continuous cultures and under nutrient starvation in batch‐mode cultures obtained by switching off nutrient supply in the continuous cultures. Under N limitation, the specific algal…
Außerordentlich wirksame kooperative Effekte bei der Bildung chiraler Stapel von C 3 ‐symmetrischen Molekülen in Alkanen als Lösungsmitteln wurden beobachtet (Bild rechts). Das „Sergeants‐and‐Soldiers”︁‐Prinzip sowie auch chirale Solvatation führen zur Ausbildung eines bevorzugten helicalen Drehsinns in den Säulenaggr…
The structure of poly (ε-caprolactam) (nylon 6) in the β mesomorphic form is here examined. The comparison of the diffraction intensity, calculated on modeled structures, with the experimental profiles, collected by us through an automatic diffractometer, is presented. This analysis has put into evidence the following…
Abstract Free radical polymerization of methyl methacrylate (MMA) within the uniform channels of the mesoporous zeolite MCM‐41 proceeds at 100°C to give a high molecular weight polymer (PMMA). The formation of long‐living propagating polymer‐radicals is observed by electron paramagnetic resonance (EPR). The molecular…
To identify novel genes and to isolate tagged mutations in known genes that are required for the development of the peripheral nervous system (PNS), we have screened a novel collection of 2460 strains carrying lethal or semilethal P element insertions on the third chromosome. Monoclonal antibody 22C10 was used as a ma…
High-energy milling provides an effective and environmentally conscious method for nanosizing silicon. Colloidal suspensions of nanosized silicon are presently demonstrated and utilized for the fabrication of high refractive index nanocomposites. Si nanoparticles with average sizes of 20−40 nm and size distributions o…
The effect of water sorption on the dielectric relaxation processes of nylon-6 samples with water concentrations ranging from the dry to the water-saturated polymer has been studied by thermally stimulated depolarization currents experiments in a broad temperature range, from 77 to 365 K. The strengths of the low-temp…
The formation of precursors and the growth and aggregation of silicalite-1 crystals using tetrapropylammonium as a template (Si-TPA-MFI) has been studied in situ using X-ray scattering techniques. Simultaneous small-angle and wide-angle X-ray scattering (respectively SAXS and WAXS) experiments using synchrotron light…
Mechanistic modeling of protein adsorption has evolved to include increasingly detailed descriptions of protein structure in an effort to capture experimentally observed behavior. This has been especially true of electrostatically driven adsorption, for which colloidal models have been used frequently. These efforts h…
We report the existence of a reversible first-order phase transition of BeS from the zinc-blende structure, $B3,$ to the nickel-arsenide structure, $B8,$ at 51 GPa with a volume change of 11%. The NiAs phase remains stable up to at least 96 GPa. A second-order Birch equation describes the equation of state of the $B3$…
Different porphyrin conformations are believed to play a role in controlling the cofactor properties in natural tetrapyrrole-protein complexes. In order to study the correlation between macrocycle nonplanarity and physicochemical properties in detail, a series of six porphyrins with graded degrees of macrocycle distor…
Vanadyl salen complexes bearing electron-withdrawing substituents have been prepared and characterized. Systematic substitutions on the ancillary ligand have allowed V(5+)/V(4+) reduction potentials to be tuned over a range of approximately 500 mV. The complexes are catalysts for the aerobic epoxidation of cyclohexene…