Color constancy by category correlation

Finding color representations that are stable to illuminant changes is still an open problem in computer vision. Until now, most approaches have been based on physical constraints or statistical assumptions derived from the scene, whereas very little attention has been paid to the effects that selected illuminants have on the final color image representation. The novelty of this paper is to propose perceptual constraints that are computed on the corrected images. We define the category hypothesis, which weights the set of feasible illuminants according to their ability to map the corrected image onto specific colors. Here, we choose these colors as the universal color categories related to basic linguistic terms, which have been psychophysically measured. These color categories encode natural color statistics, and their relevance across different cultures is indicated by the fact that they have received a common color name. From this category hypothesis, we propose a fast implementation that allows the sampling of a large set of illuminants. Experiments prove that our method rivals current state-of-art performance without the need for training algorithmic parameters. Additionally, the method can be used as a framework to insert top-down information from other sources, thus opening further research directions in solving for color constancy.     

Electrochemical degradation of clofibric acid in water by anodic oxidation: Comparative study with platinum and boron-doped diamond electrodes

Aqueous solutions containing the metabolite clofibric acid (2-(4-chlorophenoxy)-2-methylpropionic acid) up to close to saturation in the pH range 2.0-12.0 have been degraded by anodic oxidation with Pt and boron-doped diamond (BDD) as anodes. The use of BDD leads to total mineralization in all media due to the efficient production of oxidant hydroxyl radical (OH). This procedure is then viable for the treatment of wastewaters containing this compound. The effect of pH, apparent current density, temperature and metabolite concentration on the degradation rate, consumed specific charge and mineralization current efficiency has been investigated. Comparative treatment with Pt yields poor decontamination with complete release of stable chloride ion. When BDD is used, this ion is oxidized to Cl₂. Clofibric acid is more rapidly destroyed on Pt than on BDD, indicating that it is more strongly adsorbed on the Pt surface enhancing its reaction with OH. Its decay kinetics always follows a pseudo-first-order reaction and the rate constant for each anode increases with increasing apparent current density, being practically independent of pH and metabolite concentration. Aromatic products such as 4-chlorophenol, 4-chlorocatechol, 4-chlororesorcinol, hydroquinone, p-benzoquinone and 1,2,4-benzenetriol are detected by gas chromatography-mass spectrometry (GC-MS) and reversed-phase chromatography. Tartronic, maleic, fumaric, formic, 2-hydroxyisobutyric, pyruvic and oxalic acids are identified as generated carboxylic acids by ion-exclusion chromatography. These acids remain stable in solution using Pt, but they are completely converted into CO₂ with BDD. A reaction pathway for clofibric acid degradation involving all these intermediates is proposed.     

Poly(aspartic acid) Biohydrogel as the Base of a New Hybrid Conducting Material

In the present study, a composite made of conducting polymer, poly(3,4-ethylenedioxythiophene) (PEDOT), and a biodegradable hydrogel of poly(aspartic acid) (PASP) were electrochemically interpenetrated with poly(hydroxymethyl-3,4-ethylenedioxythiophene) (PHMeDOT) to prepare a new interpenetrated polymer network (IPN). Different cross-linker and PEDOT MPs contents, as well as different electropolymerization times, were studied to optimize the structural and electrochemical properties. The properties of the new material, being electrically conductive, biocompatible, bioactive, and biodegradable, make it suitable for possible uses in biomedical applications.     

Proteomic Tools for the Quantitative Analysis of Artificial Peptide Libraries: Detection and Characterization of Target-Amplified PD-1 Inhibitors

We report a quantitative proteomics data analysis pipeline, which coupled to protein-directed dynamic combinatorial chemistry (DDC) experiments, enables the rapid discovery and direct characterization of protein-protein interaction (PPI) modulators. A low-affinity PD-1 binder was incubated with a library of >100 D-peptides under thiol-exchange favoring conditions, in the presence of the target protein PD-1, and we determined the S-linked dimeric species that resulted, amplified in the protein samples versus the controls. We chemically synthesized the target dimer candidates and validated them by thermophoresis binding and protein-protein interaction assays. The results provide a proof-of-concept for using this strategy in the high-throughput search of improved drug-like peptide binders that block therapeutically relevant protein-protein interactions.     

A Metal-Organic Framework Incorporating Eight Different Size Rare-Earth Metal Elements: Toward Multifunctionality À La Carte

Multi-metallic multivariate (MTV) rare earth (RE) metal−organic frameworks (MOFs) are of interest for the development of multifunctional materials, however examples with more than three RE cations are rare and obstructed by compositional segregation during synthesis. Herein, this work demonstrates the synthesis of a multi-metallic MTV RE MOF incorporating two, four, six, or eight different RE ions with different sizes and in nearly equimolar amounts and no compositional segregation. The MOFs are formed by a combination of RE cations (La, Ce, Eu, Gd, Tb, Dy, Y, and Yb) and a 1,7-di(4-carboxyphenyl)-1,7-dicarba-closo-dodecaborane (mCB-L) linker. The steric bulkiness and acidity of mCB-L is crucial for the incorporation of different size RE ions into the MOF structure. Demonstration of the incorporation of all RE cations is performed via compositional and structural characterization. The more complex MTV MOF, including all eight RE ions (mCB-8RE), are also characterized using optical, thermal, and magnetic techniques. Element-selective X-ray absorption spectroscopy and X-ray Magnetic Circular Dichroism measurements allow us to characterize spectroscopically each of the eight RE ions and determine their magnetic moments. This work paves the way for the investigation of MTV MOFs with the possibility to combine RE ions à la carte for diverse applications.