LONG-TIME ASYMPTOTIC FOR THE DAMPED BOUSSINESQ EQUATION IN A CIRCLE

The first initial-boundary value problem for the following equation utt-αΔutt-2bΔut=αΔ^3u-βΔ^2u+Δu+γΔ（u^2) in a unit circle is considered. The existence of strong solution is established in the space C^0([0,∞),HrY^s(0,1)),s<7/2,and the solutions are constructed in the form of series in the small parameter present in the initial conditions.For 5/2<s<7/2,the uniqueness is proved.The long-time asymptotics obtained in the explicit form.     

Hollow fiber based affinity selection combined with high performance liquid chromatography–mass spectroscopy for rapid screening lipase inhibitors from lotus leaf

A novel kind of immobilized enzyme affinity selection strategy based on hollow fibers has been developed for screening inhibitors from extracts of medicinal plants. Lipases from porcine pancreas were adsorbed onto the surface of polypropylene hollow fibers to form a stable matrix for ligand fishing, which was called hollow fibers based affinity selection (HF-AS). A variety of factors related to binding capability, including enzyme concentration, incubation time, temperature, buffer pH and ion strength, were optimized using a known lipase inhibitor hesperidin. The proposed approach was applied in screening potential lipase bound ligands from extracts of lotus leaf, followed by rapid characterization of active compounds using high performance liquid chromatography–mass spectrometry. Three flavonoids including quercetin-3-O-β-d-arabinopyranosyl-(1 → 2)-β-d-galactopyranoside, quercetin-3-O-β-d-glucuronide and kaempferol-3-O-β-d-glucuronide were identified as lipase inhibitors by the proposed HF-AS approach. Our findings suggested that the hollow fiber-based affinity selection could be a rapid and convenient approach for drug discovery from natural products resources.     

Synthesis of benzofurans through coupling of dienylacetylenes with carbene complexes: total synthesis of egonol

The reaction of various carbene complexes with dienylacetylenes has been examined. The reaction has been used as the cornerstone for the preparation of the nor-neolignan natural product egonol in five steps from readily available components. In most examples of the carbene-alkyne coupling, the reaction proceeds to form benzofuran derivatives. In the case of one highly functionalized terminal alkyne, a competing rearrangement/cyclization process occurs in preference to the carbene coupling process. The use of silylated alkynes subverts this process.