Materials Literature
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Abstract Since the first edition of "Liposomes - A Practical Approach" was published in 1990, Liposome technology has become a highly successful and rapidly developing area of preclinical and clinical research. During the 90's, a number of liposome-based drugs reached the market in the U.S. and Europe and several new…
New dinuclear Au(I) complexes containing bridging thiouracilate and bis(diphenylphosphino)methane ligands have been synthesized and characterized structurally and spectroscopically. The compounds exhibit a unique behavior of solid-state luminescence tribochromism in which photoemission turns on upon gentle grinding of…
Abstract Amorphous calcium carbonate (ACC) is a precursor phase of calcite in the formation of the sea urchin larval spicule. The goal of this research is to study the formation and stabilization mode of this transient phase. We first characterized the mineralogy of the spicules from the sea urchin Strongylocentrotus…
A simple two-step dealloying strategy is described to make free-standing metal membranes with hierarchical porous architecture. This structure has a bimodal pore size distribution composed of large porosity channels and small porosity channel walls, where each pore size can be tailored independently of the others. A n…
Due to their interesting properties, research on colloidal nanocrystals has moved in the last few years from fundamental research to first applications in materials science and life sciences. In this review some recent biological applications of colloidal nanocrystals are discussed, without going into biological or ch…
We have found that the electronic transport of the binary icosahedral (i) Cd-Yb is extremely sensitive to a minute substitution of Mg for Cd atoms; the positive temperature coefficient of the resistivity (TCR) at low temperatures seen in the binary i Cd-Yb disappears by addition of only 0.1 at. % Mg and, moreover, the…
This paper reports a new quantitative method of analyzing both the earliest stage of degradation of a polymer and the surface concentration of an additive using time-of-flight secondary ion mass spectrometry (TOF-SIMS). The static SIMS spectra of triphenylamine (Ph3N)/poly(L-lactic acid) (PLLA) (20:80 wt %) blend matr…
The cold drawing of a poly(ether ester) block copolymer was studied by in-situ simultaneous small- and wide-angle X-ray scattering techniques in combination with a tensile stretching apparatus. The results obtained revealed three distinct regions in the stress−strain relationship. At low strains (0 < ε < 18%), the app…
Acetobacter xylinum BPR2001 produces water-insoluble bacterial cellulose (BC) and a water-soluble polysaccharide called acetan in corn steep liquor-fructose medium. Acetobacter xylinum EP1, which is incapable of acetan production was derived by disrupting the aceA gene of BPR2001. The BC production by EP1 (2.88 g/L) w…
Abstract The degradation of organic compounds in water is the subject of a number of fundamental and applied investigations. Aquasonolysis of organic compounds is an advanced technology for the purification of contaminated water. The process is based on the phenomenon of acoustic cavitation. Dominant reactions of vola…
Dibenzylidene sorbitol (DBS) is a low-molecular-weight organic molecule that can gel a variety of organic solvents and polymers by self-organizing into a three-dimensional nanofibrillar network through hydrogen-bonding and phenyl interactions. In this work, we investigate the composition dependence of such “organogels…
In part 1 of this series, we proposed a new method to determine the correct equilibrium melting temperature ( T m 0 ). Effects of the “melting kinetics” and lamellar thickening were omitted from T m . The correct T m 0 of isotactic polypropylene (iPP) ([ mmmm ] = 99.6%, M n = 64 × 10 3, and M w / M n = 2.4) was observ…
A new theory for the dynamics of concentrated colloidal suspensions and the colloidal glass transition is proposed. The starting point is the memory function representation of the density correlation function. The memory function can be expressed in terms of a time-dependent pair-density correlation function. An exact…
Novel biodegradable star-shaped polymers that consist of poly( l -lactide) (PLLA) arms and a starburst PAMAM dendrimer core were prepared by ring-opening polymerization of l -lactide with PAMAM-OH dendrimer (generation 1−4) initiators and a stannous octoate catalyst in bulk at 130 °C. The molecular weights of the star…
A new method to determine the correct Gibbs−Thomson plot and equilibrium melting temperature ( T m 0 ) of polymers was proposed. The Gibbs−Thomson plot method is reliable, because the Gibbs−Thomson equation is directly derived from thermodynamical relations. In this method, the heating rate dependence of melting tempe…
The DC transport properties of and the radio-frequency (RF) wave absorption (at 1.33 MHz) in a ceramic sample of La_{0.5}Sr_{0.5}CoO_{3-δ} are measured. The Curie temperature, T_{c}, of the sample is about 250 K. A giant negative magnetoabsorption effect is found. In the vicinity of T_{c}, the absolute value of the ma…
The relaxation of axisymmetric crystal surfaces with a single facet below the roughening transition is studied via a continuum approach that accounts for step energy g_1 and step-step interaction energy g_3>0. For diffusion-limited kinetics, free-boundary and boundary-layer theories are used for self-similar shapes cl…
We complete our earlier [Phys. Rev. B 66, 134435 (2002)] study of the electronic structure, exchange interactions, and Curie temperature in (GaMn)As and extend the study to two other diluted magnetic semiconductors (GaCr)As and (GaFe)As. Four concentrations of the $3d$ impurities are studied: 25, 12.5, 6.25, 3.125 %.…
In the present article, a detailed study of the optical properties of the Er-doped Si nanocrystals system, obtained through ion implantation of Er in samples containing Si nanocrystals formed by plasma enhanced chemical vapor deposition is reported. In particular, we present a phenomenological model based on an energy…
Nonlinear optical response and optical coherence of excitons in semiconductor dense quantum dots in GaAs single quantum wells has been studied by using photon echo techniques. At low temperatures, the optical coherence is estimated to be 2 ns from the decay curve in the photon echo signal. Rabi oscillations are also o…