Crystal and molecular structure of 12α-hydroxy-ent-kaur-16-en-19-oic acid

The crystal and molecular structure of the title compound has been determined by X-ray crystallographic analysis. The 12-hydroxy-ent-kaur-16-en-19-oic acid previously isolated from other sources is found for the first time in a species of theMachaeranthera genus. The unit cell contains three closely similar independent molecules organized into trimers.     

11β-Hydroxyobacunone (zapoterin)

The crystal structure of zapoterin C₂₆H₃₀O₈ isolated from Casimiroa edulis has been determined and the compound crystallizing in the monoclinic space group P2₁ with a = 7.486(1), b = 16.247(3), c = 9.736(2) Å, = 98.77(1)°, V = 1170.3(4) ų, and Z = 2 was confirmed as 11-hydroxyobacunone (11-hydroxy-14,15:21,23-diepoxy-4,4,8-trimethyl-A,D-di-homo-24-nor-4,17-dioxa-chola-1,20,22-triene-3,7,16-trione) 1. The molecule comprises a tetracyclic skeleton with homo-oxa rings A and D. In the crystal, molecules form infinite ribbons along the b axis by hydrogen bonding involving the hydroxyl group and the carbonyl group of the seven-membered lactone.     

Portfolio selection in the Spanish stock market by interactive multiobjective programming

This study examines new versions of two interactive methods to address multiobjective problems, the aim of which is to enable the decision maker to reach a solution within the range of those considered efficient in a portfolio selection model, in which several objectives are pursued concerning risk and return and given that these are clearly conflicting objectives, the profile of the model proposed is multicriteria. Normally the range of efficient portfolios is fairly extensive thus making the selection of a single one an onerous task. In order to facilitate this process, interactive methods are used aimed at guiding the decision maker towards the optimal solution based on his preferences. Several adaptations were carried out on the original methods in order to facilitate the interactive process, improving the quality of the obtained portfolios, and these were applied to data obtained from the Madrid Stock Market, interaction taking place with two decision makers, one of whom was more aggressive than the other in their selections made.     

Effect of the Constrained Environment on the Interactions between the Surfactant and Different Polar Solvents Encapsulated within AOT Reverse Micelles

Herein, we report a study of the interactions between different nonaqueous polar solvents, namely, ethylene glycol (EG), propylene glycol (PG), glycerol (GY), dimethylformamide (DMF), and dimethylacetamide (DMA), and the polar heads of sodium 1,4‐bis‐2‐ethylhexylsulfosuccinate (AOT) in nonaqueous AOT/n‐heptane reverse micelles. The goal of our study is to gain insights into the unique reverse‐micelle microenvironment created upon encapsulation of these polar solvents. For the first time, the study is focused on determining which regions of the AOT molecular structure are involved in the interactions with the polar solvents. We use FTIR spectroscopy—a noninvasive technique—to follow the changes in the AOT C?O band and the symmetric and asymmetric SO₃^? vibration modes upon increasing the content of polar solvents in the micelles. The results show that GY interacts through H bonds with the SO₃^? group, thereby removing the Na⁺ counterions from the interface remaining in the polar core of the micelles. PG and EG interact through H bonds, mainly with the C?O group of AOT, penetrating into the oil side of the interface. Thus, they interact weakly with the Na⁺ counterion, which seems to be close to the AOT sulfonate group. Finally, DMF and DMA, encapsulated inside the reverse micelles, interact neither with the C?O nor with the SO₃^? groups, but their weakly bulk‐associated structure is broken because of the interactions with Na⁺. We suggest that DMF and DMA can complex the Na⁺ ions through their carbonyl and nitrogen groups. Hence, our results do not only give insights into how the constrained environment affects the bulk properties of polar solvents encapsulated within reverse micelles but—more importantly—they also help us to answer the tricky question about which regions of the AOT moiety are involved in the interactions with the polar solvents. We believe that our results show a clear picture of the interactions present at the nonaqueous reverse‐micelle interface; this is important because these media are interesting nanoreactors for heterogeneous chemistry, templates for nanoparticles, and models for membranes.     

Nonparaxial method for computing the gradient field of a wavefront using moiré deflectometry

A nonparaxial method in moiré deflectometry to obtain the gradient field of a wavefront under test is proposed. This method uses only two deflectograms without any information about the phase object. As a result, director cosines of the gradient field are computed from moiré fringe deviations on both deflectograms without ambiguities. The method is proved by using a synthetic wavefront simulation.     

On the pulsating flow behavior of a biological fluid: human blood

In this work, the rectilinear flow of a complex fluid (human blood) under a pulsating time-dependent pressure gradient is analyzed. A first approximation of the real case of blood flowing in a vein is described. The normalized pressure gradient simulates the pumping work of the heart while the flow geometry (circular tube) is assumed rigid, smooth, and cylindrical. The rheological behavior of blood with different cholesterol levels is modeled using the Bautista–Manero–Puig (BMP) constitutive equation. According to the analytical solution, a flow enhancement is predicted to first order which represents the optimum pumping work of the heart which governs the flow of blood in the entire body. This work is a contribution to the understanding of the complex rheology involved in the discontinuous pressure-driven flow of blood in the human body.     

Multi-scale kinetic description of granular clusters: invariance,balance, and temperature

We discuss a multi-scale continuum representation of bodies made of several mass particles flowing independently each other. From an invariance procedure and a nonstandard balance of inertial actions, we derive the balance equations introduced in earlier work directly in pointwise form, essentially on the basis of physical plausibility. In this way, we analyze their foundations. Then, we propose a Boltzmann-type equation for the distribution of kinetic energies within control volumes in space and indicate how such a distribution allows us to propose a definition of (granular) temperature along processes far from equilibrium.