Search results for "oligo"
showing 10 items of 1298 documents
Folding Patterns in a Family of Oligoamide Foldamers
2015
A series of small, unsymmetrical pyridine-2,6-dicarboxylamide oligoamide foldamers with varying lengths and substituents at the end groups were synthetized to study their conformational properties and folding patterns. The @-type folding pattern resembled the oxyanion-hole motifs of enzymes, but several alternative folding patterns could also be characterized. Computational studies revealed several alternative conformers of nearly equal stability. These folding patterns differed from each other in their intramolecular hydrogen-bonding patterns and aryl-aryl interactions. In the solid state, the foldamers adopted either the globular @-type fold or the more extended S-type conformers, which w…
Steroidal saponins from Chlorophytum orchidastrum.
2009
Six new spirostane-type saponins (1−6), named orchidastrosides A−F, and chloromaloside D were isolated from an ethanol extract of the roots of Chlorophytum orchidastrum. The saponins have neotigogenin or neogitogenin as the aglycon and oligosaccharidic chains possessing seven to nine sugar units. Their structures were elucidated mainly by 2D NMR spectroscopic analyses (COSY, TOCSY, NOESY, HSQC, and HMBC) and FABMS and HRESIMS. Compounds 1−6 were tested for cytotoxicity against two human colon cancer cell lines, HCT 116 and HT-29.
Ethylene oligomerization with 2-hydroxymethyl-5,6,7-trihydroquinolinyl-8-ylideneamine-Ni(II) chlorides
2021
Abstract A series of Ni complexes of the general formula [2-(MeOH)-8-{N(Ar)}C9H8N]NiCl2, where Ar = 2,6-Me2C6H3 in Ni1; 2,6-Et2C6H3 in Ni2; 2,6-i-Pr2C6H3 in Ni3; 2,4,6-Me3C6H2 in Ni4; 2,6-Et2-4-MeC6H2 in Ni5 and 2,4,6-t-Bu3C6H2 in Ni6 has been synthesized and characterized by elemental analysis and IR spectroscopy. On activation with MMAO or Et2AlCl, these complexes showed high activity in ethylene oligomerization, reaching 2.23 × 106 g·mol–1 (Ni) h–1 at 30 °C with the Al/Ni ratio of 5500 and 9.11 × 105 g·mol–1 (Ni) h–1 with the Al/Ni of 800, respectively. Moreover, the content of α-C4 indicated high selectivity exceeding 99% in the Ni/Et2AlCl system. Comparing with the previous report by o…
Weak Interactions Modulating the Dimensionality in Supramolecular Architectures in Three New Nickel(II)-Hydrazone Complexes, Magnetostructural Correl…
2011
Three different ONO donor acetyl hydrazone Schiff bases have been synthesized from the condensation of acetic hydrazide with three different carbonyl compounds: salicylaldehyde (HL(1)), 2-hydroxyacetophenone (HL(2)), and 2, 3-dihydroxybenzaldehyde (HL(3)). These tridentate ligands are reacted with Ni(OOCCF(3))(2)·xH(2)O to yield three new Ni(II) complexes having distorted octahedral geometry at each Ni center: [Ni(L(1))(OOCCF(3))(CH(3)OH)](2) (1), [Ni(L(2))(OOCCF(3))(H(2)O)](2) (2), and [Ni(L(3))(L(3)H)](OOCCF(3))(H(2)O)(1.65)(CH(3)OH)(0.35) (3). The ligands and the complexes have been characterized by elemental analysis and IR and UV-vis spectroscopy, and the structures of the complexes ha…
Synthesis of oligodeoxynucleotides containing diastereomeric dihydrodiol epoxide-N6-deoxyadenosine adducts of polycyclic aromatic hydrocarbons
1993
Abstract A generally applicable route is reported for the synthesis of oligodeoxynucleotides which contain structurally defined N 6 -deoxyadenosine adducts, derived from sterically highly hindered dihydrodiol epoxides of polycyclic aromatic hydrocarbons (PAH).
Conformational properties and folding analysis of a series of seven oligoamide foldamers
2016
33 crystal structures (11 unsolvated and 22 solvates) of a series of seven oligoamide foldamers were analysed. The crystal structures revealed that despite the structural and environmental differences the series of foldamers prefer only two general conformations, a protohelical @-conformation and a sigmoidal S-conformation. Both conformations also have preferred crystal packing motifs and solvate forming tendencies. Hydrogen bonding was found to be the most decisive factor in conformational preference, but steric properties, the type of the peripheral substituents, as well as solvent and aromatic interactions were also found to have an effect on the conformational details and crystal form. …
Union structure and incentives for innovation
2002
Abstract In this paper, we consider the effect of union structure on the adoption of innovation in the context of Cournot duopoly. With a market size large enough, we show that the incentive to innovate is higher under a decentralized union structure (with each firm facing its own independent union) than under an industry-wide union. However, for a small market size (or, equivalently, for sufficiently drastic potential innovation), the new technology is more likely to be adopted in the presence of a centralized union. This result goes against the conventional view that unionization harms the incentive to innovate.
Fructooligosaccharide and levan producing activity of Zymomonas mobilis extracellular levansucrase
2002
Abstract The present work was devoted to investigations of the fructooligosaccharide (FOS) and levan forming activity of ethanol producing bacteria Zymomonas mobilis and their extracellular levansucrase. After cell separation the culture liquid was treated with ethanol to precipitate levan together with extracellular levansucrase. Levan–levansucrase sediment can be used as biocatalyst for fructooligosaccharide (FOS) production in sucrose syrup and levan sediment as soluble fibre source. The dynamics of sucrose conversion and glucose, fructose, and FOS formation by extracellular levansucrase showed that the fructose content increased only during the first 6 h, while the glucose content conti…
Superparamagnetic γ-Fe2O3 nanoparticles with tailored functionality for protein separation
2007
Polymer coated superparamagnetic gamma-Fe(2)O(3) nanoparticles were derivatized with a synthetic double-stranded RNA [poly(IC)], a known allosteric activator of the latent (2-5)A synthetase, to separate a single 35 kDa protein from a crude extract which cross reacted with antibodies raised against the sponge enzyme.
Mittel- und nordeuropäische Weberknechte aus dem Senckenberg Museum Frankfurt (Arachnida: Opiliones)
2005
Central and North European harvestmen from the Senckenberg Museum Frankfurt (Arachnida: Opiliones). About 1100 individuals belonging to 32 opilionid species (300 series), mainly of German origin, were identified based on material provided by, and stored at, the Senckenberg Museum, Frankfurt (Main). A list of all species with habitat information is included. Comments on two remarkable species (Oligolophus hanseni, Odiellus spinosus) are given. The comments include the importance of some series as reference material from MARTENS (1978), additions to regional faunas and the expansion of the known distribution of some thermophilous species.