Materials Literature
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We show that when a typically antiferroelectric material such as ${\mathrm{PbZrO}}_{3}$ or ${\mathrm{BiNbO}}_{4}$ is deposited as a thin film on a semiconducting substrate (Si), it displays ferroelectric behavior below a critical film thickness characteristic of the system. In an attempt to understand this ``size effe…
The bifunctional P-protein, which plays a central role in Escherichia coli phenylalanine biosynthesis, contains two catalytic domains (chorismate mutase and prephenate dehydratase activities) as well as one R-domain (for feedback inhibition by phenylalanine). Six genes coding for P-protein domains or subdomains were c…
Detailed measurements of the acoustic emissions from single-bubble sonoluminescence have been made utilizing both a small 200-μm aperture PVDF needle hydrophone, and a focused 10-MHz transducer. Signals obtained with the needle hydrophone show a fast (5.2 ns), probably bandlimited rise time and relatively large pulse…
The effect of curing temperature on the electro-optic behaviour and network morphology of reverse mode polymer stabilized cholesteric textures (PSCTs) has been studied. Scanning electron micrographs indicate that increasing the curing temperature generally results in a larger average void size within a polymer network…
An inexpensive electrochemical capacitor system with an asymmetric configuration is demonstrated. The system includes heteropolyacids and a proton‐exchange polymer membrane. Heteropolyacid electrodes show facile redox processes and host large amounts of easily accessible mobile protons required for charge balance. The…
Recent studies of potential components for nanomachines reveal that for a wide variety of structures, the rigidity of the structure is a key element in its proper performance. Vibrational analysis is an ideal way to study structural rigidity, but standard methods of molecular vibrational analysis are computationally p…
This study demonstrates the shielding effects of a silica-ash layer on the combustion of silicones and their possible applications on the fire retardancy of organic materials. The deposited silica-ash layer, formed on the surface of silicone materials during combustion, has shielding effects on the combustion of silic…
ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTSwitching on the Nucleophilic Reactivity of a Ferric Porphyrin Peroxo ComplexMatthias Selke and Joan Selverstone ValentineView Author Information Department of Chemistry and Biochemistry University of California, Los Angeles Los Angeles, California 90095-1589 Cite this…
ABSTRACT Water sorption, water vapor permeability, and tensile properties were evaluated for zein films plasticized with oleic acid. The effect of relative humidity on water vapor permeability and tensile properties of films was investigated. Samples were produced by two different methods: casting from a zein solution…
The electrochemical behavior of thin sputter‐deposited mixed oxide films with ‐contents of 10, 20, 50, and 90% was studied with in situ X‐ray absorption near edge spectroscopy (XANES). These measurements gave information on the chemical states and dissolution rates during anodic and cathodic polarization in different…
ABSTRACT Transglutaminase (TG) was used to produce films from whey protein isolate, soybean 11S globulin and a mixture of the two (1:1, wt/wt). Solubility of TG cross‐linked films was lower than that of control films at pH 3, 4, 6 and 8. Solubility of control films in 6.6M urea and in 10% SDS was higher than that of T…
The coherency defect technique is developed for the domain pattern energetics in rhombohedral (001) epitaxial ferroelectric films. The coherency defects that are necessary to maintain the epitaxy during the ferroelectric phase transition are considered to be the only sources of elastic strains and stresses (and, corre…
The first nucleobase-functionalized polythiophenes, e.g., the uracil-substituted polythiophene shown in the Figure, produced by electrochemical oxidation of bithiophenes covalently linked to the nucleobases uracil and adenine, are reported. Their synthesis, characterization, and polymerization are detailed and the inf…
Abstract The claystones and mudstones investigated are London Clay, Fullers Earth, Oxford Clay and Kimmeridge Clay. The thermal conductivities were measured using a divided bar apparatus and the values measured perpendicular to layering ranged from 0.68 to 0.97 W/mK. Comparative measurements of thermal conductivities…
Epitaxial ultrathin films of BaTiO3 were prepared using molecular beam epitaxy. For the substrate, (001)-oriented SrTiO3 single crystals were used. Controlling the growth conditions of these films as well as the semiconductor thin films, led to the successful growth of the BaTiO3 films as single crystals, characterize…
Skin loss due to burns and ulcers is a major medical problem. Bioengineered skin substitutes that use cultured keratinocytes as an epidermal layer with or without analogues of the dermis are one strategy for skin repair. However, none can achieve definitive wound closure, function, or cosmesis comparable to split-thic…
Phase separation of poly(lactide) (PLA) and poly(lactide-co-glycolide) (PLGA), often called "coacervation" in the pharmaceutical field, is one of the classical methods for peptide drug microencapsulation in biodegradable polyesters. Although numerous studies have used this technique, the underlying physicochemical mec…
Pyrolysis of different polysilazanes has been used to prepare novel covalent amorphous ceramics composed of silicon, carbon, and nitrogen. The formation and structure of the as-pyrolyzed amorphous state and its devitrification into stable crystalline phases have been investigated by means of nuclear magnetic resonance…
Three helicase structures have been determined recently: that of the DNA helicase PcrA, that of the hepatitis C virus RNA helicase, and that of the Escherichia coli DNA helicase Rep. PcrA and Rep belong to the same super-family of helicases (SF1) and are structurally very similar. In contrast, the HCV helicase belongs…
Abstract Iron(II)-containing minerals are potential inorganic nitrate reductants in soils and sediments. Specifically, synthetic green rust (Fe 4 II Fe III 2 (OH) 12 SO 4 . y H 2 O, GR) reduces nitrate to ammonium. The reaction of GR with two different nitrate salts, NaNO 3 and Ba(NO 3 ) 2 , has been compared. The rea…