Bioactive eremophilanolides from Senecio poepigii

A new bioactive eremophilanolide, 1alpha-tigloyloxy-8betaH,10betaH-eremophil-7(11)-en-8alpha,12-olide, was isolated from Senecio poepigii and its structure was elucidated by spectral analysis. 1alpha-Angeloyloxy-8beta-methoxy-10betaH-eremophil-7(11)-en-8alpha,12-olide was also isolated. Antifungal and insect antifeedant properties were evaluated.     

Groups satisfying weak chain conditions on non-modular subgroups

In this paper (generalized) soluble groups for which the set of all non-modular subgroups satisfies some weak chain condition are described. Groups satisfying weak chain conditions on non-permutable subgroups are also considered.     

Large-scale supramolecular structure in solutions of low molar mass compounds and mixtures of liquids: II. Kinetics of the formation and long-time stability

Kinetics of the formation of large-scale supramolecular structure and its long-time stability were investigated in detail in solutions of electrolytes, nonelectrolytes, and mixtures of liquids. This structure comprises submicron-sized domains (large clusters) with higher solute concentration than in the rest of solution. In the case of mixtures of liquids, a complete real-time monitoring of the structure formation was possible in all cases. In the case of solutions of solid samples, the observation was possible in cases when the structure formation was significantly slower than the dissolution process. The time scale on which the supramolecular structure develops varies from minutes to weeks, depending on the concrete system. The long-time stability of the developed structure was investigated in time intervals ranging up to 15 months. In some systems the resulting domain structure appears stable, in others a very slow ceasing of domains is observed over very long time intervals. In all cases, however, slow kinetic effects are present in the systems investigated. Among others, data on some common substances of great chemical and biological importance such as sodium chloride, acetic acid, glucose, and ethanol, are presented.     

Ant colony optimization for the arc routing problem with intermediate facilities under capacity and length restrictions

The aim of this paper is to introduce a new ant colony optimization procedure for the Arc Routing Problem with Intermediate Facilities under Capacity and Length Restrictions (CLARPIF), a variant of the Capacitated Arc Routing Problem (CARP) and of the Capacitated Arc Routing Problem with Intermediate Facilities (CARPIF). Computational results show that this algorithm is capable of providing substantial improvements over other known heuristics.     

Counting BPS States on the Enriques Calabi-Yau

We study topological string amplitudes for the FHSV model using various techniques. This model has a type II realization involving a Calabi-Yau threefold with Enriques fibres, which we call the Enriques Calabi-Yau. By applying heterotic/type IIA duality, we compute the topological amplitudes in the fibre to all genera. It turns out that there are two different ways to do the computation that lead to topological couplings with different BPS content. One of them gives the standard D0-D2 counting amplitudes, and from the other one we obtain information about bound states of D0-D4-D2 branes on the Enriques fibre. We also study the model using mirror symmetry and the holomorphic anomaly equations. We verify in this way the heterotic results for the D0-D2 generating functional for low genera and find closed expressions for the topological amplitudes on the total space in terms of modular forms, and up to genus three. This model turns out to be much simpler than the generic B-model and might be exactly solvable.     

A decomposition approach to solve a bilevel capacitated facility location problem with equity constraints

In this paper, we study a capacitated facility location problem with two decision makers. One (say, the leader) decides on which subset of facilities to open and the capacity to be installed in each facility with the goal of minimizing the overall costs; the second decision maker (say, the follower), once the facilities have been designed, aims at maximizing the profit deriving from satisfying the demands of a given set of clients beyond a certain threshold imposed by the leader. The leader can foresee but cannot control the follower’s behavior. The resulting mathematical formulation is a discrete–continuous bilevel optimization problem. We propose a decomposition approach to cope with the bilevel structure of the problem and the integrality of a subset of variables under the control of the leader. Such a proposal has been tested on a set of benchmark instances available in the literature.     

Determination of topotecan in human and mouse plasma and in mouse tissue homogenates by reversed-phase high-performance liquid chromatography

A sensitive and selective reversed-phase high-performance liquid chromatographic (HPLC) assay has been developed and validated for quantification of total topotecan in human and mouse plasma and in mouse tissue samples. Isocratic separation was achieved on a Zorbax SB-C(18) column and topotecan was monitored fluorimetrically. Two ranges of calibrations curves were used to determine lower levels of topotecan more accurately. Acceptable accuracy and precision was achieved for all matrices. Topotecan was stable upon repeated freeze-thawing for three cycles or storage for 24 h at ambient temperatures in spiked plasma samples and tissue homogenates, except in heart homogenates. In an additional validation experiment in which (14)C-labeled topotecan was administered to mice, the levels of unchanged topotecan were about 80-90% of the total radioactivity in tissue homogenates collected 10 min after drug administration and virtually similar as in plasma samples. However, results in tissue homogenates obtained 4 h post-drug administration indicated substantial metabolism of topotecan. This assay is suitable for studying the pharmacokinetics and tissue distribution of topotecan in mice. Our results demonstrate the importance of including all tissues of interest for pharmacokinetic studies in the validation procedure.