Influence of surface ordering on the wetting of structured liquids

The substrate is shown to induce substantial ordering in diblock copolymer thin films above the bulk order-disorder transition (ODT) where, thermodynamically, a phase mixed state is favored. Initially, uniform films reorganize to form a hierarchy of transient surface patterns and stable film thicknesses that depend on the initial film thickness and on the substrate. Self-consistent field calculations of the free energy of the system for different situations, depending on the relative tendency for the different block components to be attracted to the substrate and/or free surface, provide an explanation of the formation of the stable film thicknesses. A continuum picture proposed earlier by Brochard et al.rovides an explanation of the wetting characteristics of this system. In some cases the ordering destabilizes the film so that dewetting occurs (wetting autophobicity), whereas in other cases the surface ordering results in a kinetic stabilization of a film that would otherwise dewet. Received 3 August 2001 and Received in final form 1 November 2001     

Synthesis of high-mannose type neoglycolipids: active targeting of liposomes to macrophages in gene therapy

The concise synthesis of five biantennary oligomannose neoglycolipids is presented. Employing a strategy based on the principles of reactivity tuning and orthogonal activation, the oligomannose moieties, isolated from the glycoprotein 63 of the parasite Leishmania mexicana amazonensis, were rapidly assembled taking advantage of common structural motifs found in these N-glycans. Deprotection of all structures was achieved in high yield by hydrogenolysis. The deprotected glycoconjugates were subsequently coupled to a cholesteroldiamine derivative using diethylsquarate as a linker. The resulting neoglycolipids will be used as additives to cationic liposome formulations in the active targeting of liposomes to macrophages.     

The Macromolecular Route to Chiral Amplification

Cooperative phenomena, described by one-dimensional statistical physical methods, are observed between the enantiomeric characteristics of monomeric materials and the polymers they produce. The effect of minute energies associated with this amplified chirality, although currently not interpretable, can be easily measured. Nonlinear relationships between enantiomeric excess or enantiomeric content and polymer properties may offer the possibility of developing chiral catalysts and chiral chromatographic materials in which the burden of large enantiomeric excess or content may be considerably alleviated. New approaches to information and sensor technology may become possible.     

Synthesis and molecular structure of [CpRu(1,4,7-S3C6H12)]O3SCF3

The isolation and characterization of [CpRu(9S3)](O₃SCF₃), where 9S3 = 1,4,7-trithiacyclononane, is reported. The title compound crystallizes in the orthorhombic space group Pbca: a = 10.2542(18), b = 14.8991(13), c = 22.4832(18) Å, and Z = 8. The Ru atom is sandwiched between the -bound cyclopentadienyl ligand and the 9S3 ligand, bonding to all three of the sulfur atoms in the 9S3. The Ru—S distances are 2.2991(10), 2.2979(11), and 2.3055(10) Å. The C—S distances range from 1.819(4) to 1.852(5) Å in the trithiacyclononane ring.     

Design of electricity supply networks

The problem of designing a secure electricity supply network at minimal cost is formulated as a mathematical program. It is also shown how computationally convenient new constraints may be derived and these are added to the original set. The problem is dualized and solved approximately. It is indicated how this approach can be built into a Branch-and-Bound scheme for solving the original design problem, and an illustrative example is given.     

Rapid assays based on immobilized bioluminescent enzymes and photographic detection of light-emission

Sensitive assays have been developed for adenosine 5'-triphosphate, the reduced form of nicotinamide adenine dinucleotide, cholyl glycine and alcohol, with immobilized and co-immobilized preparations of bacterial and firefly luciferase as reagents. With high-speed (ASA 20000) instant photographic film as detector, picomole amounts of the various analytes can be detected rapidly. The simplicity and convenience of the analytical combination of co-immobilized bioluminescent enzymes and photographic film for the detection of light make this an ideal technique for rapid screening tests.