Excited state aromatization assisted push-pull abilities of two unsaturated oxazolone derivatives

Molecular structures of two unsaturated oxazolone derivatives involving furan rings, which are decorated with p-tolyl (FurM) and 4-nitro phenyl (FurN), were investigated by X-ray crystallography and quantum chemical calculations. Their ground and excited states were examined by DFT and TD-DFT computations with the aid of topological electron density studies, NBO and Charge Decomposition Analysis. Both compounds have push-pull (D–π–A) framework using oxazolone ring as π-linker. Depending on the transitions from the ground to excited states, intramolecular charge transfer (ICT) in both compounds results in aromatization of oxazolones. Push-pull ability of FurN has more pronounced than that of FurM. The use of furan instead of almost fully aromatic benzenoid ring reduces HOMO?LUMO band gap due to relatively low aromaticity level of furan. Introduction of nitro substituent leads to a further reduction in HOMO?LUMO gap. In addition, electronic redistribution in the excited state results in aromatization of oxazolone moieties without elongation of carbonyl bonds.     

Evaluation of in vivo analgesic activity of Scrophularia kotscyhana and isolation of bioactive compounds through activity-guided fractionation

The present study was undertaken to evaluate the in vivo analgesic activities of the extracts prepared from the aerial parts and roots of Scrophularia kotscyhana and to isolate the bioactive metabolites from the most active extract. Analgesic activities of all extracts and subextracts at the doses of 5, 10 and 30 mg/kg (i.p.) were examined using hot plate test in mice. Among the tested extracts, MeOH extract prepared from the aerial parts and the n-butanol subextract prepared thereof displayed the best analgesic activity at all doses. Phytochemical studies on n-butanol subextract led to the isolation of two new iridoid glycosides as an inseparable mixture, 8-O-acetyl-4′-O-(E)-(p-coumaroyl)-harpagide (1) and 8-O-acetyl-4′-O-(Z)-(p-coumaroyl)-harpagide (2) along with five known secondary metabolites, β-sitosterol 3-O-β-glucopyranoside (3), apigenin 7-O-β-glucopyranoside (4), apigenin 7-O-rutinoside (5), luteolin 7-O-β-glucopyranoside (6) and luteolin 7-O-rutinoside (7). The iridoid mixture (1 and 2), 3 and 4 elicited significant inhibition of pain at 5 mg/kg dose.     

Identification of irradiated pulses by thermoluminescence of the contaminating minerals

Thermoluminescence (TL) response of contaminating minerals from six samples of pulses commonly consumed in Pakistan has been studied for identification of irradiation treatment. The samples were irradiated by Co-60 gamma rays at 0.3, 0.5 and 1.0 kGy, or by 10 MeV electrons using an accelerator at 0.75 and 2.2. kGy. Generally, the TL intensity for minerals separated from irradiated samples was higher than for unirradiated samples. To normalize the results, separated minerals deposited on stainless steel discs were re-irradiated by a normalizing dose and TL response was redetermined. The ratio of the area of the first glow curve to the second glow curve was more than 0.8 for all irradiated samples and less than 0.33 for most of the unirradiated samples. For those unirradiated samples where the ratio of the glow curves was more then 0.03, the shapes of the glow curves were compared. Taking this criterion into consideration, all 21 unirradiated and irradiated samples of pulses were identified correctly. Therefore, a normalization procedure by re-irradiation of minerals and analysis of TL glow curve shapes lead to unequivocal identification of radiation treatment of pulses.     

Locating concentrators in centralized computer networks

Topological design of centralized computer communication networks is a complex problem that is generally solved in two phases. The first phase of the design process involves dividing network nodes (terminals or clusters of terminals) into groups, and selecting a concentrator location for each group so that all the nodes in a group are assigned to the same concentrator. The next phase determines topology of links that connect network nodes to concentrators and concentrators to each other and to the central computer. The design problem studied in this paper contains some aspects of both phases. In this problem locations of concentrators, assignments of user nodes to concentrators and the topology of the links connecting concentrators to the central computer are jointly determined. The proposed design method is built around the well known sweep heuristic which is used to partition the node space into sectors. Each of these sectors contain a backbone path connecting concentrators to the central computer.