A multiplexing architecture for mixed-signal CMOS fuzzy controllers

Limits to precision impose limits to the complexity of analog circuits, hence fuzzy analog controllers are usually oriented to fast low-power systems with low-medium complexity. This paper presents a strategy to preserve most of the advantages of an analog implementation, while allowing a marked increment in system complexity.The works in this papaer has been partially funded by the spanish C.I.C.Y.T. under contract TIC96-1392-C02-02 (SIVA

β‑Carotene Assay Revisited. Application To Characterize and Quantify Antioxidant and Prooxidant Activities in a Microplate

The β-carotene bleaching assay, a common method for evaluating antioxidant activity, has been widely criticized due to its low reproducibility, problematic quantification, complex reagent preparation, and interference of different factors (temperature, pH, solvents, and metals). In this work we have examined the effects of these factors and developed a highly reproducible procedure for microplate assay, evaluated the critical points of the method, and proposed a kinetic model for quantifying both antioxidant and prooxidant activities. The application of these tools produced very consistent results, which provide robust and meaningful criteria to compare in detail the characteristics of several well-known commercial antioxidants, as well as several predictable prooxidants, and can be easily applied to natural extracts, food samples, and many other type of compounds. As an example, we have tested a set of commercial antioxidants and some typical lipophilic prooxidants. The activity of the tested antioxidants decreased in the following order: ethoxyquin ≫ α-tocopherol > butylhydroxyanisole > butylhydroxytoluene ≫ propyl gallate. On the other hand, hemoglobin and Fe²⁺, Fe³⁺, Co²⁺, and Cu²⁺ showed a strong prooxidant effect, and the activity was null in Cd²⁺, Ni²⁺, and Sr²⁺, slightly antioxidant in Mg²⁺, and strongly antioxidant in Zn²⁺ and Mn²⁺

Influence of Sulfur Incorporation into Nanoporous Anodic Alumina on the Volume Expansion and Self-Ordering Degree

Self-ordering degree of anodic alumina nanopores is related to the volume expansion of the aluminum oxide. However, little is known about how the ionic species derived from electrolyte affect parameters inducing self-ordering of the nanopores. The influence of sulfur incorporation into nanoporous anodic aluminum oxide (AAO) films on volume expansion and self-ordering degree has been investigated under potentiostatic conditions (14–25 V) in different sulfuric acid electrolytes (3–20 wt %), the average current densities of each anodization being in the range of 0.1–10 mA cm^–2. Rutherford backscattering spectroscopy (RBS) reveals that the incorporation of sulfur species into AAO, as well as the volume expansion factor (VEF), follows a logarithmic dependence on the average current density regardless of the applied voltage and sulfuric acid concentration. The relationship between volume expansion and the S/Al ratio is linear for each concentration of acid in the electrolyte. Furthermore, self-ordering regimes are also revealed for each acid concentration at VEF in the range of 1.50–1.66. We suggest that plasticity, enhanced by sulfur incorporation, counterbalances the high mechanical stress generated by volume expansion, thus inducing new self-ordering regimes. These new regimes are dependent not only on VEF but also on a subtle equilibrium between stress and plasticity of the nanoporous AAO films

Subtle C–H···Hal (Hal = Cl, Br) Bonding as Predominant Synthon in the Assembly of Supramolecular Architectures Based on Luminescent Tin(IV) Complexes. Crystallography, Hirshfeld Surfaces, DFT Calculations, and Fluorescence

This report illustrates a successful C–H···Hal synthon-directed strategy to promote supramolecular aggregation of molecular luminescent complexes <b>1</b>–<b>6</b> into two- or three-dimensional supramolecular architectures. The tin complexes were prepared from the reaction of R_<i>n</i>SnHal_4–<i>n</i> compounds (R = <i>n</i>-Bu, Ph; Hal = Cl, Br; <i>n</i> = 0, 1) with (C₅H₄N)­HCN­(C₆H₄)­EH Schiff bases by either step-by-step synthesis [E = O (PyNO)] or multicomponent reaction [E = S (PyNS)]. Compounds <b>1</b>–<b>6</b> were characterized by IR, Raman, and ¹H, ¹³C, and ¹¹⁹Sn NMR spectroscopic studies as well as by X-ray diffraction studies. In addition, the fluorescent properties of all compounds were also investigated in the solid state and in THF solutions; the emission wavelengths ranged from orange to red (λ_max = 591–626 nm). Detailed structural characterization of the supramolecular organization of ordered solids revealed overall 2D and 3D interlinked networks driven by extensive C–H···Hal–Sn (Hal = Cl, Br) weak hydrogen bonds as primordial synthon and further stabilized by π···π stacking interactions as well as C–H···π, C–H···O, or C–H···N contacts. Hirshfeld surface analysis and DFT calculations were used to asses additional insights into crystal structural features

A Positive Allosteric Modulator of the Serotonin 5‑HT_2C Receptor for Obesity

The 5-HT_2CR agonist lorcaserin, clinically approved for the treatment of obesity, causes important side effects mainly related to subtype selectivity. In the search for 5-HT_2CR allosteric modulators as safer antiobesity drugs, a chemical library from Vivia Biotech was screened using ExviTech platform. Structural modifications of identified hit VA240 in synthesized analogues <b>6</b>–<b>41</b> afforded compound <b>11</b> (<i>N</i>-[(1-benzyl-1<i>H</i>-indol-3-yl)­methyl]­pyridin-3-amine, VA012), which exhibited dose-dependent enhancement of serotonin efficacy, no significant off-target activities, and low binding competition with serotonin or other orthosteric ligands. PAM <b>11</b> was very active in feeding inhibition in rodents, an effect that was not related to the activation of 5-HT_2AR. A combination of <b>11</b> with the SSRI sertraline increased the anorectic effect. Subchronic administration of <b>11</b> reduced food intake and body weight gain without causing CNS-related malaise. The behavior of compound <b>11</b> identified in this work supports the interest of a serotonin 5-HT_2CR PAM as a promising therapeutic approach for obesity

Synthesis of <i>exo</i>-Imidazolidin-2-one Dienes, Their Isomerization, and Selectivity in Diels–Alder Cycloadditions

An efficient and alternative synthesis of <i>exo</i>-imidazolidin-2-one dienes is described. A condensation reaction was carried out with bis-imino derivatives, diacetyl, and triphosgene, affording symmetrically <i>N</i>,<i>N</i>-disubstituted dienes. The use of alkyl methyl α-diketones led to the formation of nonsymmetrical dienes, which underwent isomerization to provide more stable <i>inner-outer</i>-ring dienes under Lewis acid conditions. Evaluation was made of the reactivity as well as regio- and stereoselectivity of these dienes in Diels–Alder reactions. They proved to be highly reactive and selective. DFT calculations of the transition states accounted for their behavior