Modification of Poly(ether imide) Membranes via Surface-Initiated Atom Transfer Radical Polymerization
10.1021/ma0520601
Materials Literature
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Diethyl 2,7-Dibromo-4 H ,5 H - thieno[3,2- b :4,5- b ‘]dipyrrole-3,6- dicarboxylate: A Key Intermediate for a Diversity Oriented Synthesis of 2,7,12,17-Tetraarylporphycenes
A new Suzuki-based strategy for the synthesis of 4,4'-diaryl (or heteroaryl)-substituted 2,2'-bipyrroles (10), precursors of 2,7,12,17-tetraaryl (or heteroaryl)-substituted porphycenes, is described. Bromination of the previously described diethyl 4H,5H-thieno[3,2-b:4,5-b']dipyrrole-3,6-dicarboxylate afforded dibromo…
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Abstract Poly(methyl methacrylate) (PMMA)/copper hydroxy methacrylate (CHM) composites were prepared via solution blending and bulk polymerization. Addition of 3% by weight of the CHM additive using solution blending resulted in a significant increment (∼45°C) in thermogravimetric analysis (TGA) T 50 , the temperature…
Pattern Registration Between Spherical Block‐Copolymer Domains and Topographical Templates
Pattern registration is achieved in thin films of self-assembling block copolymers by using a topographical template to guide the positions of the polymer domains. The placement accuracy of the polymer domains is related to the edge roughness of the topographical template, and the ultimate placement accuracy is assess…
A gold standard set of mechanistically diverse enzyme superfamilies
Superfamily and family analyses provide an effective tool for the functional classification of proteins, but must be automated for use on large datasets. We describe a 'gold standard' set of enzyme superfamilies, clustered according to specific sequence, structure, and functional criteria, for use in the validation of…
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We report polarized and unpolarized neutron scattering measurements of the magnetic order in single crystals of Na0.5CoO2. Our data indicate that below TN=88 K the spins form a novel antiferromagnetic pattern within the CoO2 planes, consisting of alternating rows of ordered and nonordered Co ions. The domains of magne…
Crystalline particle packings on a sphere with long-range power-law potentials
The original Thomson problem of ``spherical crystallography'' seeks the ground state of electron shells interacting via the Coulomb potential; however one can also study crystalline ground states of particles interacting with other potentials. We focus here on long-range power-law interactions of the form $1∕{r}^{\ens…
Mixed Protein Blends Composed of Gelatin and Bombyx mori Silk Fibroin: Effects of Solvent-Induced Crystallization and Composition
Novel protein blends have been prepared by mixing gelatin (G) with Bombyx mori silk fibroin (SF) and using aqueous methanol (MeOH) to post-induce SF crystallization. When co-cast from solution, amorphous blends of these polymers appear homogeneous, as discerned from visual observation, microscopy, and Fourier-transfor…
Properties of Aged Montmorillonite−Wheat Gluten Composite Films
The properties of new and aged glycerol-plasticized vital wheat gluten films containing < or =4.5 wt % natural or quaternary ammonium salt modified montmorillonite clay were investigated. The films were cast from pH 4 or pH 11 ethanol/water solutions. The films, aged for < or =120 days, were characterized by tensile t…
Crystalline water ices
Recent publications on the structures of crystalline water ices are surveyed. Interconversions of crystalline and amorphous ices are considered. Some hypotheses concerning the occurrence of high-pressure ices in nature are outlined.
Peptide-Mediated Cell Transport of Water Soluble Porphyrin Conjugates
Five new porphyrin-peptide conjugates bearing a nuclear localizing sequence SV40 or a fusogenic peptide (HIV-1Tat 40-60 or octa-arginine) linked by low molecular weight poly(ethylene glycol) have been synthesized. In vitro studies using human HEp2 cells show that the cellular uptake of the conjugates depends significa…
Control of the orientation of thin open supported columnar liquid crystal films by the kinetics of growth
We report a study of the growth and of the orientation of thin open supported columnar liquid crystal films by thermal annealing. We show that there is a competition between planar and homeotropic orientations (columns respectively oriented parallel and perpendicular to the solid substrate) of the liquid crystal, whic…
Photocontrolled Variations in the Wetting Capability of Photochromic Polymers Enhanced by Surface Nanostructuring
The wetting characteristics of surfaces of polymers doped with photochromic spiropyran molecules can be tuned when irradiated with laser beams of properly chosen photon energy. The hydrophilicity is enhanced upon UV laser irradiation since the embedded nonpolar spiropyran molecules convert to their polar merocyanine i…
Evaluation of Gd(III)DTPA‐terminated poly(propylene imine) dendrimers as contrast agents for MR imaging
Different generations of Gd(III)DTPA-terminated poly(propylene imine) dendrimers {G1 [n = 4 Gd(III) ions per molecule], G3 (n = 16) and G5 (n = 64)} and reference Gd(III)DTPA complex [G0 (n = 1)] were characterized in terms of (i) longitudinal (r1) and transverse (r2) relaxivities in mouse blood plasma, (ii) concentra…
Quadratic string method for determining the minimum-energy path based on multiobjective optimization
Based on a multiobjective optimization framework, we develop a new quadratic string method for finding the minimum-energy path. In the method, each point on the minimum-energy path is minimized by integration in the descent direction perpendicular to path. Each local integration is done on a quadratic surface approxim…
Curvature-dependent metastability of the solid phase and the freezing-melting hysteresis in pores
We recapitulate and generalize the concept of the freezing-melting hysteresis that attributes this phenomenon to a free-energy barrier between metastable and stable states of pore-filling material. In a phenomenological description, we show that under commonly encountered conditions, this renders the freezing-point de…
Role of charge doping and lattice distortions in codoped Mg_{1-x}(AlLi)_{x}B_2 compounds
We prepared a series of Mg_{1-x}(AlLi)_{x}B_2 samples with 0≤x≤0.45 in order to compensate with Li the electron doping induced by Al. Structural characterization by means of neutron and X-ray diffraction confirms that Li enters the MgB2 structure even though in an amount less than nominal one. We performed susceptibil…
Local oxidation of Ga[Al]As heterostructures with modulated tip-sample voltages
Nanolithography based on local oxidation with a scanning force microscope has been performed on an undoped GaAs wafer and a Ga[Al]As heterostructure with an undoped GaAs cap layer and a shallow two-dimensional electron gas. The oxide growth and the resulting electronic properties of the patterned structures are compar…