Selective Inhibition of an Apicoplastic Aminoacyl‐tRNA Synthetase from Plasmodium falciparum

The resistance of malaria parasites to available drugs continues to grow, and this makes the need for new antimalarial therapies pressing. Aminoacyl‐tRNA synthetases (ARSs) are essential enzymes and well‐established antibacterial targets and so constitute a promising set of targets for the development of new antimalarials. Despite their potential as drug targets, apicoplastic ARSs remain unexplored. We have characterized the lysylation system of Plasmodium falciparum, and designed, synthesized, and tested a set of inhibitors based on the structure of the natural substrate intermediate: lysyl‐adenylate. Here we demonstrate that selective inhibition of apicoplastic ARSs is feasible and describe new compounds that that specifically inhibit Plasmodium apicoplastic lysyl‐tRNA synthetase and show antimalarial activities in the micromolar range.     

Conservation Properties of Unstructured Finite-Volume Mesh Schemes for the Navier-Stokes Equations

The Navier-Stokes equations describe fluid flow by conserving mass and momentum. There are two main mesh discretizations for the computation of these equations, the collocated and staggered schemes. Collocated schemes locate the velocity field at the same grid points as the pressure one, while staggered discretizations locate variables at different points within the mesh. One of the most important characteristic of the discretization schemes, aside from accuracy, is their capacity to discretely conserve kinetic energy, specially when solving turbulent flow. Hence, this work analyzes the accuracy and conservation properties of two particular collocated and staggered schemes by solving various problems.     

Effect of antifungal hydroxypropyl methylcellulose-lipid edible composite coatings on Penicillium decay development and postharvest quality of cold-stored "Ortanique" mandarins

Edible composite coatings based on hydroxypropyl methylcellulose (HPMC), hydrophobic components (beeswax and shellac), and food preservatives with antifungal properties were evaluated on "Ortanique" mandarins during long-term cold storage. Selected food preservatives included potassium sorbate (PS), sodium benzoate (SB), sodium propionate (SP), and their mixtures. Intact mandarins or mandarins artificially inoculated with the pathogens Penicillium digitatum and Penicillium italicum, the causal agents of citrus postharvest green (GM) and blue (BM) molds, respectively, were coated and stored up to 8 wk at 5 °C + 1 wk of shelf-life at 20 °C. HPMC-lipid coatings containing food preservatives controlled better GM than BM on Ortanique mandarins. SB- and SB + SP-based coatings reduced the incidence of GM by about 35% after 4 wk at 5 °C. Among all coatings, only the SB-based coating reduced the incidence of GM (about 16%) after 6 wk at 5 °C. All coatings significantly reduced disease severity of both GM and BM after 6 wk at 5 °C. Analytical and sensory fruit quality was evaluated on intact mandarins. All coatings, especially the SB + SP-based coatings, were effective to control weight loss and maintain the firmness of coated mandarins. Internal gas concentration, juice ethanol and acetaldehyde content, sensory flavor, off-flavor, and fruit appearance were not adversely affected by the application of the antifungal coatings. Further studies should focus on the modification of some physical characteristics of the coatings to improve the gloss and visual aspect of treated mandarins.     

Materials with Giant Mechanocaloric Effects: Cooling by Strength

The search for materials with large caloric effects has become a major challenge in material science due to their potential in developing near room‐temperature solid‐state cooling devices, which are both efficient and clean, and that can successfully replace present refrigeration technologies. There are three main families of caloric materials: magnetocaloric, electrocaloric, and mechanocaloric. While magnetocaloric and electrocaloric materials have been studied intensively in the last few decades, mechanocaloric materials are only very recently receiving a great deal of attention. The mechanocaloric effect refers to the reversible thermal response of a solid when subjected to an external mechanical field, and encompasses both the elastocaloric effect, corresponding to a uniaxial force, and the barocaloric effect, which corresponds to the response to hydrostatic pressure. Here, the state of the art in giant mechanocaloric effects is reviewed and a critical analysis of the thermodynamic quantities that characterize the major families of barocaloric and elastocaloric materials is provided. Finally perspectives for further development in this area are given.     

Expanding the propositional logic of a t-norm with truth-constants: completeness results for rational semantics

In this paper we consider the expansions of logics of a left-continuous t-norm with truth-constants from a subalgebra of the rational unit interval. From known results on standard semantics, we study completeness for these propositional logics with respect to chains defined over the rational unit interval with a special attention to the completeness with respect to the canonical chain, i.e. the algebra over $[0,1] \cap {{\mathbb{Q}}}In this paper we consider the expansions of logics of a left-continuous t-norm with truth-constants from a subalgebra of the rational unit interval. From known results on standard semantics, we study completeness for these propositional logics with respect to chains defined over the rational unit interval with a special attention to the completeness with respect to the canonical chain, i.e. the algebra over [0,1] ?\mathbbQ[0,1] \cap {{\mathbb{Q}}} where each truth-constant is interpreted in its corresponding rational truth-value. Finally, we study rational completeness results when we restrict ourselves to deductions between the so-called evaluated formulae.     

A Taxonomy of Recommender Agents on the Internet

Recently, Artificial Intelligence techniques have proved useful inhelping users to handle the large amount of information on the Internet.The idea of personalized search engines, intelligent software agents,and recommender systems has been widely accepted among users who requireassistance in searching, sorting, classifying, filtering and sharingthis vast quantity of information. In this paper, we present astate-of-the-art taxonomy of intelligent recommender agents on theInternet. We have analyzed 37 different systems and their references andhave sorted them into a list of 8 basic dimensions. These dimensions arethen used to establish a taxonomy under which the systems analyzed areclassified. Finally, we conclude this paper with a cross-dimensionalanalysis with the aim of providing a starting point for researchers toconstruct their own recommender system.     

An Approach to Disaggregating Total Household Water Consumption into Major End-Uses

The aim of this project is to assign domestic water consumption to different devices based on the information provided by the water meter. We monitored a sample of Barcelona and Murcia with flow switches that recorded when a particular device was in use. In addition, the water meter readings were recorded every 5 and 1 s, respectively, in Barcelona and Murcia. The initial work used Barcelona data, and the method was later verified and adjusted with the Murcia data. The proposed method employs an algorithm that characterizes the water consumption of each device, using Barcelona to establish the initial parameters which, afterwards, provide information for adjusting the parameters of each household studied. Once the parameters have been adjusted, the algorithm assigns the consumption to each device. The efficacy of the assignation process is summarized in terms of: sensitivity and specificity. The algorithm provides a correct identification rate of between 70 % and 80 %; sometimes even higher, depending on how well the chosen parameters reflect household consumption patterns. Considering the high variability of the patterns and the fact that use is characterized by only the aggregate consumption that the water meter provides, the results are quite satisfactory.