6alpha-Angeloylplatynecine: a new alkaloid from Senecio nemorensis subsp. fuchsii (C.C. Gmelin) celak

The new alkaloid 6alpha-angeloylplatynecine, together with other four known pyrrolizidine alkaloids was identified from above ground parts of Senecio nemorensis subs. fuchsii.     

Hypepontine,a new quaternary alkaloid with antimicrobial properties

Abstract

New isoquinoline alkaloid hypepontine (1) together with a five known compounds, were identified in Hypecoum ponticum Velen, the partial synonym of Hypecoum procumbens L. The structure of the new substance was elucidated based on spectroscopic evidence. The tertiary and quaternary alkaloid mixtures as well as the isolated alkaloids were evaluated for their antibacterial and antifungal activity. The result revealed that the crude alkaloid mixture containing quaternary isoquinoline alkaloids showed potent antifungal and antibacterial activity.     

Synthesis,characterization and cytotoxicity evaluation of new cerium(III), lanthanum(III) and neodymium(III) complexes

Complexes of cerium(III), lanthanum(III) and neodymium(III) with coumarin‐3‐carboxylic acid (HCCA) were synthesized by mixing of equimolar amounts of the respective metal nitrates and coumarin‐3‐carboxylic acid in ethanol. The complexes were characterized and identified by elemental analysis, IR and Raman spectroscopy. DTA and TGA were applied to study the compositions of the compounds. The vibrational study showed bidentate coordination of CCA^? to Ln(III) ions through the carbonyl oxygen and the carboxylic oxygen atoms. The newly synthesized compounds were assayed for cytotoxicity against SKW‐3, HL‐60 and Reh cells. The complexes of cerium(III) and lanthanum(III) showed marginal cytotoxic activity against SKW‐3 and Reh cells as compared with the inorganic salts at concentration 200 µM . The complex of neodymium(III) induced approximately 50% reduction of the survival HL‐60 and SKW‐3 cells at concentration 200 µM . Copyright © 2007 John Wiley & Sons, Ltd.     

Kinetics of copper slag oxidation under nonisothermal conditions

The kinetics of air copper slag oxidation under nonisothermal conditions is studied using simultaneous TG–DTA at a varying heating rate of slag and flow rate of the oxidizing gas flux. The values of the kinetic parameters, activation energy and pre-exponential factor, have been determined based on: data from DTA by the methods of Kissinger and Ozawa; data from TG using an isoconversion method and the computation procedures of Ozawa–Flynn–Wall and Kissinger–Akahira–Sunose. No relationship between the kinetic parameters and the oxidation gas flow rate has been established. The changes of the phase composition with temperature are investigated by X-ray powder diffraction analysis on the basis of data obtained for the products formed at the different stages of the oxidation process. The morphology of the oxidized slag as well as the elements distribution is studied by electron microscopy and EDS analysis.     

Photoluminescent layered Y(III) and Tb(III) silicates doped with Ce(III)

The synthesis and structural characterization of new layered rare-earth silicates K(3)[M(1-a)Ce(a)Si(3)O(8)(OH)(2)], M = Y(3+), Tb(3+), a < 1 (AV-22 materials), have been reported. These materials combine the properties of layered silicates, such as intercalation chemistry, and photoluminescence and may find applications in new types of sensor devices. For mixed Tb/Ce-AV-22, evidence has been found for the energy transfer from the large Ce(3+) 4f( 1) --> 5d(1) broad band to the sharp Tb(3+) 4f (8) lines. This energy transfer allows the fine-tuning of the color emission in the blue-green region of the chromaticity diagram. Upon Ce(3+) excitation (342 nm), the radiance of Tb/Ce-AV-22 is approximately 2 times higher than that measured under direct Tb(3+) excitation, which reinforces the existence of effective room-temperature Ce(3+)-to-Tb(3+) energy transfer.     

Models for capacitated lot-sizing problem with backlogging,setup carryover and crossover

Setup operations are significant in some production environments. It is mandatory that their production plans consider some features, as setup state conservation across periods through setup carryover and crossover. The modelling of setup crossover allows more flexible decisions and is essential for problems with long setup times. This paper proposes two models for the capacitated lot-sizing problem with backlogging and setup carryover and crossover. The first is in line with other models from the literature, whereas the second considers a disaggregated setup variable, which tracks the starting and completion times of the setup operation. This innovative approach permits a more compact formulation. Computational results show that the proposed models have outperformed other state-of-the-art formulation.     

State of cobalt and molybdenum in cobalt-molybdenum-containing zeolites

NaY and CaHY zeolites containing 7 wt.% Mo and 0.7 wt.% Co have been studied by means of IR and diffuse reflectance spectroscopy (DRS). It is shown that ammonium heptamolybdate (AHM) interacts with the zeolite forming a silicon molybdenum heteropoly complex (SiMo HPC). In contrast to NaY, along with SiMo HPC, MoO₃ is formed on CaHY after calcining.

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NaY CaY , 7 .% Mo 0,7 .% Co, . , , (SiMo HPC). NaY, CaHY SiMo HPC MoO₃.

     

Lignans and Alkaloids from Haplophyllum suaveolens

Summary.  A new lignan of the dibenzylbutyrolactone type, haplotonin, was isolated from the aerial parts of Haplophyllum suaveolens together with five known compounds-the alkaloids flindersine, 6-methoxyflindersine, N-acetoxymethylflindersine, and evoxine and the lignan 4-acetyldiphyllin. This is the first report on the occurrence of N-acetoxymethylflindersine in the genus Haplophyllum and on 6-methoxyflindersine and 4-acetyldiphyllin as constituents of the investigated species. Received August 10, 1999. Accepted (revised) October 12, 1999     

A fourth‐order method for numerical integration of age‐ and size‐structured population models

In many applications of age‐ and size‐structured population models, there is an interest in obtaining good approximations of total population numbers rather than of their densities. Therefore, it is reasonable in such cases to solve numerically not the PDE model equations themselves, but rather their integral equivalents. For this purpose quadrature formulae are used in place of the integrals. Because quadratures can be designed with any order of accuracy, one can obtain numerical approximations of the solutions with very fast convergence. In this article, we present a general framework and a specific example of a fourth‐order method based on composite Newton‐Cotes quadratures for a size‐structured population model. © 2008 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq, 2009