Materials Literature
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Solubility of glucose isomerase (from Streptomyces rubiginosus ) crystals was measured in situ at 0.1 and 100 MPa. An equilibrium temperature of the crystal with the solution of a given concentration was measured using a two-beam interferometer. The solubility of the crystal decreased to about one-ninth with increasin…
ADVERTISEMENT RETURN TO ISSUEPREVCommunication to the...Communication to the EditorNEXTPoly(p-phenylene ethynylene) BrushesJoong Ho Moon and Timothy M. SwagerView Author Information Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 Cite this: Macromolecules 2002, 35, 16, 60…
Polymer-dispersed liquid crystals (PDLCs), consisting of a dispersion of LC-rich domains in a polymer matrix, are used in different types of electrooptical devices. Their efficiency can in principle be increased if the LC domains exhibit a uniform characteristic size in the range of the wavelength of visible light. In…
The solubility of potassium carbonate in methanol and the acid−base interaction of these compounds with each other have been considered. The reaction results in the formation of methoxide and hydrocarbonate of potassium. The reported values on the solubility of potassium carbonate differ essentially from the data desc…
A backbone-caged sperm-activating peptide (caged speract) that has a 2-nitrobenzyl group at a backbone amide and a vastly reduced affinity for its receptor (IC50=950 nM) was synthesized. UV irradiation of caged speract photocleaves the 2-nitrobenzyl group (tau1/2=26 micros), restoring its affinity (IC50=0.67 nM) and a…
Hydrogen-bonded supramolecular cation assemblies of (NH4+/NH2-NH3+)(crown ether), where the crown ether is [12]crown-4, [15]crown-5, or [18]crown-6, were incorporated into electrically conducting [Ni(dmit)2] salts (dmit2- = 2-thioxo-1,3-dithiole-4,5-dithiolate). (NH4+)([12]crown-4)[Ni(dmit)2]3(CH3CN)2 had a pyramidal…
This paper comprises the text of a review lecture on the subject of the effects of ultrasound upon mass transport, upon electrode surface phenomena, upon the behaviour of species and upon reaction mechanisms, and selected examples of the benefits of insonation in electroanalysis, electrosynthesis, electrodeposition an…
The structural evolution of a 2D hexagonal mesoporous silica powder during nitrogen adsorption at low temperature is followed by X-ray diffraction. The values for the pore radius and wall microporosity obtained with this technique compare well to the estimations drawn from volumetric measurements. It is further shown…
Antimony compounds are widely used as catalysts for the synthesis of the commercially important polymer poly(ethyleneterephthalate) by polycondensation of bis(hydroxyethyl)terephthalate. The precise nature of the antimony catalysts is, however, unknown. The present study has been conducted with a view to determining t…
This report describes the synthesis and supramolecular organization of a novel class of linear−dendritic block copolymers. The molecules, which are termed rodcoil dendrons, consist of a cholesterol moiety that is attached to l -lysine dendrons of three different generations via a biodegradable oligo( l -lactic acid) n…
The positive axial zero-field splitting parameter D relevant for the S = 2 ground state of [Mn(cyclam)I2]I (cyclam = 1,4,8,11-tetraazacyclotetradecane) is interpreted using the valence bond configuration interaction model which explicitly considers the covalency of the manganese-iodide bond.
An investigation was carried out of the molecular dynamics of poly( l -lactic acid) before, during, and after crystallization. Experimental results were generated over a wide range of temperature and frequency by broad-band dielectric relaxation spectroscopy (DRS). An interesting finding is that the average relaxation…
A new reversible isomerization cycle for meta-ferrocenylazobenzene accomplished by combination of a single green light (546 nm) and redox change between Fe(II) and Fe(III) was discovered. In the Fe(II) state, trans-to-cis isomerization proceeded upon the green light irradiation exciting the metal-to-ligand charge tran…
We present a new family of peptide dendrimers based on polyproline helices and cis-4-amino-L-proline as a branching unit. Dendrimers were synthesized by a convergent solid-phase peptide synthesis approach. The conformational transition between polyproline type I helix and polyproline type II helix was observed by circ…
We report the synthesis of the dibutyl derivative of poly(3,4-propylenedioxythiophene) as a regiosymmetric and soluble electroactive and photoluminescent conjugated polymer obtained in the neutral form by a Grignard metathesis coupling reaction. Molecular weights have been characterized by gel permeation chromatograph…
The conduction propertes of PVDF polymer gel electrolytes prepared by the phase inversion method were investigated through the diffusion coefficient and conductivity in order to confirm the conduction mechanism. The gel conductivity is associated with the total solution uptake which depends on the gelation process. Th…
We develop the extended dynamical mean field theory (E-DMFT) with a view towards realistic applications. {\bf 1)} We introduce an intuitive derivation of the E-DMFT formalism. By identifying the Hartree contributions before the E-DMFT treatment, it allows to handle systems in symmetry breaking phases within a simple f…
Two new polyoxetanes bearing dimesogenic pendants were prepared and their liquid crystalline properties were studied by differential scanning calorimetry (DSC), polarizing microscopy, and X-ray diffractometry. The dimesogens consist of cholesterol and biphenyl moieties connected through polymethylene spacers. Their bi…
ZnS quantum dots (QDs) synthesized in water and ethanol solutions were coated with polystyrene (PS) and SiO 2 shells, respectively. The band edge emission was enhanced by nearly five times after PS coating and by about thirteen times after SiO 2 coating, because the surface trap states were removed. From the photolumi…
The structure of the alpha-(Al,Si)CuFe approximant phase is determined by a single-crystal X-ray diffraction study and compared to the ideal structure obtained by the perpendicular shear method of the parent icosahedral phase. It is shown that the local environments (typical atomic clusters) of the two phases are simi…