An operator representation for weighted spaces of vector valued holomorphic functions

For any weighted space HV(G) of holomorphic functions on an open set G ? ?^Nwith a topology stronger than that of uniform convergence on the compact sets and for any quasibarrelled space E we prove the topological isomorphism $HV(G,E_{b}^{\prime})={\cal L}_b(E,HV(G))$ and derive a similar, more complicated isomorphism for weighted spaces of continuous functions. This generalizes results of [3], [7] and [6] and should be compared with the ∈-product representations for the corresponding spaces of functions with o-growth conditions. At the end we also show the topological isomorphism HV₁(G₁, HV₂(G₂)) = H (V₁ ? V₂)(G₁ × G₂).     

Crystalline inclusion compounds derived from bulky organosilicon hosts – design, synthesis, structure and stability

New organosilicon compounds 1–3 featuring bulky triphenylsilyl moieties attached to rigid linear or trigonal spacer units have been synthesized and demonstrated to act as clathrate hosts, yielding crystalline inclusion compounds mostly with apolar and aprotic dipolar guest molecules, while the nonbulky dimethylphenylsilyl or trimethylsilyl substituted analogous compounds 4 and 5, which were also synthesized, proved inefficient. X-ray crystal structures of the inclusion compounds 1·DMF (1:1), 1·pyridine (1:1), 2·1,4-dioxane (2:1), 2·pyridine (2:1), 2·p-xylene (2:1), 2·H₂O (2:1) as well as of the unsolvated compounds 2 and 5 are described, and thermal stability studies of selected clathrates are reported.     

On the shape of bottle-brush macromolecules: systematic variation of architectural parameters

We measured the form factor of bottle-brush macromolecules under good solvent conditions with small-angle neutron scattering and static light scattering. The systems under investigation are brushes, synthesized via the grafting-from route, built from a poly(alkyl methacrylate) backbone to which poly(n-butyl acrylate) side chains are densely grafted. The aim of our work is to study how the systematic variation of structural parameters such as the side chain length and backbone length change the conformation of the polymer brushes in solution. All spectra can be consistently described by a model, considering the bottle-brush polymers as flexible rods with internal density fluctuations. Parameters discussed are (1) the contour length per main chain monomer l(b), (2) the fractal dimension of the side chains Ds, as well as (3) the fractal dimension D, and (4) the Kuhn length lambdak of the overall brush. l(b)=0.253+/-0.008 nm is found to be independent of the side chain length and equal to the value found for the bare main chain, indicating a strongly stretched conformation for the backbone due to the presence of the side chains. The fractal dimension of the side chains is determined to be Ds=1.75+/-0.07 which is very close to the value of 10.588 approximately 1.70 expected for a three-dimensional self-avoiding random walk (3D-SAW) under good solvent conditions. On larger length scales the overall brush appears to be a 3D-SAW itself (D=1.64+/-0.08) with a Kuhn-step length of lambdak=70+/-4 nm. The value is independent of the side chain length and 46 times larger than the Kuhn length of the bare backbone (lambdak=1.8+/-0.2 nm). The ratio of Kuhn length to brush diameter lambda(k)d>or=20 determines whether lyotropic behavior can be expected or not. Since longer side chains do not lead to more persistent structures, lambda(k)d decreases from 8 to 4 with increasing side chain length and lyotropic behavior becomes unlikely.     

Encapsulated living cells on microstructured surfaces

The immobilization of cells in defined arrays (cell patterning) is a key step towards cell-based biosensors or other cell-based devices. While cell patterning is usually achieved by modifying the surface on which only the cells should adhere and leaving the cells unmodified, we present here a different approach in which cells are first coated with polyelectrolytes and subsequently immobilized on patterned surfaces. By coating, the cells are protected and their interactions with the substrate are modified such that patterning is simplified. We used microcontact printing of polyelectrolytes to structure surfaces such that regions of opposite charges and the same charge as the cell coating were present and found that we can thus achieve patterning of the coated yeast cells. In accordance with prior work, we find that coating does not kill the cells and coated GFP-expressing cells still function after immobilization, which we checked by fluorescence microscopy.     

Nucleotides,Part LXIII,New 2-(4-Nitrophenyl)ethyl(Npe)- and 2-(4-Nitrophenyl)ethoxycarbonyl(Npeoc)-Protected 2′-Deoxyribonucleosides and Their 3′-Phosphoramidites – Versatile Building Blocks for Oligonucleotide Synthesis

A series of new base-protected and 5′-O-(4-monomethoxytrityl)- or 5′-O-(4,4′-dimethoxytrityl)-substituted 3′-(2-cyanoethyl diisopropylphosphoramidites) and 3′-[2-(4-nitrophenyl)ethyl diisopropylphosphoramidites] 52 – 66 and 67 – 82 , respectively, are prepared as potential building blocks for oligonucleotide synthesis (see Scheme). Thus, 3′,5′-di-O-acyl- and N ²,3′-O,5′-O-triacyl-2′-deoxyguanosines can easily be converted into the corresponding O⁶-alkyl derivatives 6 , 8 , 10 , 12 , 14 , and 16 by a Mitsunobu reaction using the appropriate alcohol. Mild hydrolysis removes the acyl groups from the sugar moiety (→ 9 , 11 , 13 , 15 , and 19 (via 18 ), resp.) which can then be tritylated (→ 38 – 42 ) and phosphitylated (→ 57 – 61 ) in the usual manner. N ²-[2-(4-nitrophenyl)ethoxycarbonyl]-substituted and N ²-[2-(4-nitrophenyl)ethoxycarbonyl]-O⁶-[2-(4-nitrophenyl)ethyl]-substituted 2′-deoxyguanosines 5 and 7 , respectively, are synthesized as new starting materials for tritylation (→ 28 , 35 , and 37 ) and phosphitylation (→ 54 , 56 , 70 , and 78 ). Various O⁴-alkylthymidines (see 20 – 24 ) are also converted to their 5′-O-dimethoxytrityl derivatives (see 43 – 47) and the corresponding phosphoramidites (see 62 – 66 and 79 – 82 ).