Centro de Investigación y Desarrollo Tecnológico en Electroquímica

About: Centro de Investigación y Desarrollo Tecnológico en Electroquímica is a based out in . It is known for research contribution in the topics: Cyclic voltammetry & Catalysis. The organization has 537 authors who have published 682 publications receiving 10382 citations. The organization is also known as: Centro de Investigacion y Desarrollo Tecnologico en Electroquimica & Center of Research and Technologic Development in Electrochemistry.

Morphological image enhancement and segmentation

Abstract: Publisher Summary This chapter discusses some basic concepts of mathematical morphology (MM). The notion of morphological slope filters (MSF) and their algebraic properties are introduced, and the sequential morphological slope filters are described in the chapter. The chapter focuses on image enhancement and segmentation by using a class of morphological nonincreasing filters called “morphological slope filters.” The notion of morphological gradients was used to build this class of MSF. The idea of retaining the zones of the image with a strong gradient and attenuating the other ones gives good contrast enhancement. Image segmentation using MSF is described, and new results concerning MSF on graphs are discussed in the chapter. Although image-enhancement techniques are generally empirical, this technique has a well-defined theoretical framework, expressed by a set of properties that permits a better understanding of the technique. By applying the MSF in a sequential way, new properties are found that enable us to retain more features from the original image. By increasing the contrast at each step of the sequence of filters, the filtering process is better controlled.

The π-Back-Bonding Modulation and Its Impact in the Electronic Properties of CuII Antineoplastic Compounds: An Experimental and Theoretical Study

Abstract: A complete study of the electronic density distri- bution in antineoplastic mixed chelate complexes of the type (Cu(NN)(glycinate)H2O)NO3 (NN = 2,2'-bipyridine (bpy) (1), 4,4'-dimethyl-bpy (2), 5,5'-dimethyl-2,2'-bipyridine (3), 1,10-phenanthroline (phen) (4), 4-methyl-phen (5); 5- methyl-phen (6); 4,7-dimethyl-phen (7), 5,6-dimethyl-phen (8), and 3,4,7,8-tetramethyl-phen (9)), a family known as Ca- siopenas, was carried out with cyclic voltammetry, EPR, and computational methods. Crystal structures of 1·H2O, 2·H2O, 3·H2O, 6·H2O, and 8·H2O show the variability in the geome- tries adopted by the copper compounds in the solid state. Experimental properties are described employing electronic descriptors obtained from computational methods. The main descriptors found were: The total electronic population of the metal ion (N(Cu)), delocalization of the metal ion elec- trons over the donor atoms (D(Cu)), atomic dipolar moment (m(Cu)), and the atomic quadrupole moment (Q(Cu)). It was found that p-back-bonding is the principal factor that modu- lates the distribution of the electron density around the metal ion. The electronic descriptors obtained from the com- putational approach can be used as electronic descriptors of inorganic compounds that have shown antiproliferative ac- tivities instead the experimental data, aiding the rational design of good candidates of metal-based drugs.

Atomic scale reversible opto-structural switching of few atom luminescent silver clusters confined in LTA zeolites

Abstract: Luminescent silver clusters (AgCLs) stabilized inside partially Ag exchanged Na LTA zeolites show a remarkable reversible on–off switching of their green-yellowish luminescence that is easily tuned by a hydration and dehydration cycle, making them very promising materials for sensing applications. We have used a unique combination of photoluminescence (PL), UV-visible-NIR Diffuse Reflectance (DRS), X-ray absorption fine structure (XAFS), Fourier Transform-Infrared (FTIR) and electron spin resonance (ESR) spectroscopies to unravel the atomic-scale structural changes responsible for the reversible optical behavior of the confined AgCLs in LTA zeolites. Water coordinated, diamagnetic, tetrahedral AgCLs [Ag4(H2O)4]2+ with Ag atoms positioned along the axis of the sodalite six-membered rings are at the origin of the broad and intense green-yellowish luminescence in the hydrated sample. Upon dehydration, luminescent [Ag4(H2O)4]2+ clusters are transformed into non-luminescent (dark), diamagnetic, octahedral AgCLs [Ag6(OF)14]2+ with Ag atoms interacting strongly with zeolite framework oxygen (OF) of the sodalite four-membered rings. This highly responsive on–off switching reveals that besides quantum confinement and molecular-size, coordinated water and framework oxygen ligands strongly affect the organization of AgCLs valence electrons and play a crucial role in the opto-structural properties of AgCLs.