Materials Literature
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New resorbable and elastomeric ABA tri- and multiblock copolymers have been successfully synthesized by combining ring-opening polymerization with ring-opening polycondensation. Five different poly(L-lactide-b-1,5-dioxepan-2-one-b-L-lactide) triblock copolymers and one new poly(L-lactide-b-1,5-dioxepan-2-one) multiblo…
A new series of phthalocyanine-containing biodegradable copolymers, namely poly(phthalocyanine- co -sebacic anhydride) (Pc-SA), have been synthesized. For copolymers with a low Pc content, the Pc rings exist mainly as monomeric species in chloroform, while the aggregation of these macrocycles becomes significant as th…
Argon adsorption at 77 K on ordered mesoporous silicas (MCM-41, SBA-15) with pore diameters up to 9 nm and on disordered mesoporous silicas with larger pore sizes was investigated, allowing us to successfully develop a method to calculate pore size distributions (PSDs) for cylindrical pores with diameters below 15 nm.…
A series of asymmetric tetraarylporphyrins was synthesized from pyrrole, para-substituted oligo- or poly(ethylene glycol) monomethyl ether benzaldehyde and from 4-hydroxybenzaldehyde etherified with diethyl bromomalonate according to the Lindsey method. After hydrolysis of the tetraarylporphyrin esters, the resulting…
In this report, we present data demonstrating that cylindrical metallic particles, with various submicrometer striping patterns, may be readily distinguished in an optical microscope. Accurate particle identification is discussed relative to synthesis reproducibility and the limitations of optical microscopes. Results…
Polyelectrolyte multilayers deposited onto particles are exploited as thin films for localizing sol−gel reactions of inorganic precursors at particle surfaces, yielding core−shell colloids with defined shell thicknesses. The image shows silica colloids coated with a polyelectrolyte/titania shell.
To combine the cytotoxic activity of cisplatin and the phototoxicicity of hematoporphyrin derivatives in the same molecule, hematoporphyrin was derivatized at the two secondary alcohol positions by etherification with oligo- and poly(ethylene glycol) units. The two carboxylic acid groups of the propionate side chains…
Siliceous MCM-48 spheres are tailored with silane coupling agents, n -octyldimethylchlorosilane (C8) and (3-aminopropyl)triethoxysilane (APTS). The changes in adsorption features of water and acetaldehyde with the modifications are elucidated by aid of adsorption calorimetry. The MCM-48 surface exhibits a hydrophobic…
The ability to construct three- and two-dimensional architectures via nanoscale engineering is important for emerging applications of nanotechnology in sensors, catalysis, controlled drug delivery, microelectronics, and medical diagnostics. In this paper, we report novel 3D assembly using multidentate molecular buildi…
Gold−titania (Au−TiO 2 ) composite aerogels were synthesized, characterized, and tested as ambient-temperature oxidation catalysts for carbon monoxide. Adding alkanethiolate-monolayer-protected gold clusters (with ∼2-nm Au cores) directly to titania sol before gelation yields uniformly dispersed guests in the composit…
Novel oligo[poly(ethylene glycol) fumarate] (OPF) hydrogels functionalized with cell adhesion peptides were prepared, and the effects of incorporated peptide density and macromolecular structure of hydrogels on attachment and morphology of marrow stromal cells (MSCs) were evaluated. Poly(ethylene glycol) (PEG; number…
A facile high-yield synthetic route has been established for the synthesis of α-hydroxy methyl ketones. These intermediates are important precursors to the tricyanovinyldihydrofuran type of acceptor used in high μβ nonlinear optical chromophores. 3-Hydroxy-3-methyl-2-butanone is one of only three commercially availabl…
Non-covalent functionalization of carbon nanotubes (CNTs) is of paramount importance for developing new nanomaterials without destruction of the electrical properties of the CNTs. In this paper, we report a simple approach to immobilize tetra-tert-butylphthalocyanines (tBuPcs) on CNTs. The immobilization results from…
We report on the synthesis of high quality La$_{1/3}$Sr$_{2/3}$FeO$_3$ (LSFO) thin films using the pulsed laser deposition technique on both SrTiO$_3$ (STO) and LaAlO$_3$ (LAO) substrates (100)-oriented. From X-Ray diffraction (XRD) studies, we find that the films have an out-of-plane lattice parameter around 0.3865nm…
Recent experimental observations have found two different kinds of ``strange kinetic behaviors" in individual semiconductor nanocrystals (or quantum dots). Fluorescence intermittency observed in the quantum dots shows power--law statistics in both {\it on} and {\it off} times. Spectral diffusion of the quantum dots is…
Bulk MgB2 - based materials with the following critical current densities (jc) in 1 T field: 570 kA/cm^2 at 10 K, 350 kA/cm^2 at 20 K and 40 kA/cm^2 at 30 K and in 10 T field: 650 A/cm^2 at 10 K have been high-pressure (HP) synthesized from Mg and B with 2 - 10 wt.% addition of Ta. In synthesis and sintering process T…
The description of the early stage of microfracture growth in a quasibrittle solid with thermodynamic positions is considered. From the most general thermodynamic performances the "principle" of minimization of free energy is received. The account high (down to thirds) degrees in expansion of free energy concerning pa…
A method of soldering of melt-textured YBa2Cu3O7-d -based (MT-YBCO) superconductive blocks using a TmBaCu3O7-d (Tm123) powder has been suggested. The method excludes stages of slow cooling during soldering and preparation of auxiliary layers. To estimate the critical current density (jc) through the obtained junction,…
We propose a model for explaining the recent results obtained by J. Schon et al (1,2) on transport properties of electrons and holes in one plane of CuO2 in a layered cuprate (CaCuO2) where the carriers are created using a field effect transistor (FET). We use the known band structure of a CuO2 plane showing a van Hov…
Density functional calculations for full structures of dimers of Cu(II) complexes linked via O-H...O hydrogen bonds provide exchange-coupling constants that are in excellent agreement with experimentally reported values. Magneto-structural correlations between the exchange-coupling constant and the O...O distance or t…