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901.
Mireya Santander-Nelli Bastin Boza Felipe Salas David Zambrano Luis Rosales Paulina Dreyse 《Molecules (Basel, Switzerland)》2022,27(9)
With an appropriate mixture of cyclometalating and ancillary ligands, based on simple structures (commercial or easily synthesized), it has been possible to design a family of eight new Ir(III) complexes (1A, 1B, 2B, 2C, 3B, 3C, 3D and 3E) useful as luminescent materials in LEC devices. These complexes involved the use of phenylpyridines or fluorophenylpyridines as cyclometalating ligands and bipyridine or phenanthroline-type structures as ancillary ligands. The emitting properties have been evaluated from a theoretical approach through Density Functional Theory and Time-Dependent Density Functional Theory calculations, determining geometric parameters, frontier orbital energies, absorption and emission energies, injection and transport parameters of holes and electrons, and parameters associated with the radiative and non-radiative decays. With these complexes it was possible to obtain a wide range of emission colours, from deep red to blue (701–440 nm). Considering all the calculated parameters between all the complexes, it was identified that 1B was the best red, 2B was the best green, and 3D was the best blue emitter. Thus, with the mixture of these complexes, a dual host–guest system with 3D-1B and an RGB (red–green–blue) system with 3D-2B-1B are proposed, to produce white LECs. 相似文献
902.
Jose Luis Ropero-Vega Joshua Felipe Redondo-Ortega Juliana Paola Rodríguez-Caicedo Paola Rondn-Villarreal Johanna Marcela Flrez-Castillo 《Molecules (Basel, Switzerland)》2022,27(9)
The detection of pathogens through alternative methodologies based on electrochemical biosensors is being studied. These devices exhibit remarkable properties, such as simplicity, specificity, and high sensitivity in monitoring pathogens. However, it is necessary to continue conducting studies that adequately improve these characteristics, especially the recognition molecule. This work aims to design and evaluate a new peptide, named PEPTIR-2.0, as a recognition molecule in electrochemical biosensors to detect E. coli O157:H7 in water. PEPTIR-2.0 was obtained from modifications of the PEPTIR-1.0 peptide sequence, which was previously reported and exhibited excellent properties for detecting and quantifying this pathogenic microorganism. PEPTIR-1.0 is a peptide analogous to the TIR (Translocated Intimin Receptor) protein capable of interacting with the Intimin outer membrane. The basis of this study was to obtain, by using bioinformatics tools, a molecule analogous to PEPTIR-1.0 that maintains its three-dimensional structure but increases the hydrophobic interactions between it and Intimin, since these intermolecular forces are the predominant ones. The designed PEPTIR-2.0 peptide was immobilized on screen-printed electrodes modified with gold nanoparticles. The detection capacity of E. coli O157:H7 in water was evaluated using electrochemical impedance spectroscopy in the presence of other microorganisms, such as P. aeruginosa, S. aureus, and non-pathogenic E. coli. The results showed that PEPTIR-2.0 confers remarkable specificity to the biosensor towards detecting E. coli, even higher than PEPTIR-1.0. 相似文献
903.
Flvia A. R. dos Santos Jadriane A. Xavier Felipe C. da Silva J. P. Jose Merlin Marília O. F. Goulart H. P. Vasantha Rupasinghe 《Molecules (Basel, Switzerland)》2022,27(13)
The objective of this work was to investigate the antidiabetic, antiglycation, and antioxidant potentials of ethanolic extract of seeds of Brazilian Passiflora edulis fruits (PESE), a major by-product of the juice industry, and piceatannol (PIC), one of the main phytochemicals of PESE. PESE, PIC, and acarbose (ACB) exhibited IC50 for alpha-amylase, 32.1 ± 2.7, 85.4 ± 0.7, and 0.4 ± 0.1 µg/mL, respectively, and IC50 for alpha-glucosidase, 76.2 ± 1.9, 20.4 ± 7.6, and 252 ± 4.5 µg/mL, respectively. The IC50 of PESE, PIC, and sitagliptin (STG) for dipeptidyl-peptidase-4 (DPP-4) was 71.1 ± 2.6, 1137 ± 120, and 0.005 ± 0.001 µg/mL, respectively. PESE and PIC inhibited the formation of advanced glycation end-products (AGE) with IC50 of 366 ± 1.9 and 360 ± 9.1 µg/mL for the initial stage and 51.5 ± 1.4 and 67.4 ± 4.6 µg/mL for the intermediate stage of glycation, respectively. Additionally, PESE and PIC inhibited the formation of β-amyloid fibrils in vitro up to 100%. IC50 values for 1,1-diphenyl-2-picrylhydrazyl radical (DPPH•) scavenging activity of PESE and PIC were 20.4 ± 2.1, and 6.3 ± 1.3 µg/mL, respectively. IC50 values for scavenging hypochlorous acid (HOCl) were similar in PESE, PIC, and quercetin (QCT) with values of 1.7 ± 0.3, 1.2 ± 0.5, and 1.9 ± 0.3 µg/mL, respectively. PESE had no cytotoxicity to the human normal bronchial epithelial (BEAS-2B), and alpha mouse liver (AML-12) cells up to 100 and 50 µg/mL, respectively. However, 10 µg/mL of the extract was cytotoxic to non-malignant breast epithelial cells (MCF-10A). PESE and PIC were found to be capable of protecting cultured human cells from the oxidative stress caused by the carcinogen NNKOAc at 100 µM. The in vitro evidence of the inhibition of alpha-amylase, alpha-glucosidase, and DPP-4 enzymes as well as antioxidant and antiglycation activities, warrants further investigation of the antidiabetic potential of P. edulis seeds and PIC. 相似文献
904.
Debabrata Dhara Felipe Fantuzzi Marcel Hrterich Rian D. Dewhurst Ivo Krummenacher Merle Arrowsmith Conor Pranckevicius Holger Braunschweig 《Chemical science》2022,13(33):9693
We report the reduction of bulky ferrocenyl-based NHC-stabilised aluminium(iii) diiodide [Fc*(NHC)AlI2] (Fc* = 2,5-bis(3,5-di-tert-butylphenyl)-1-ferrocenyl) in different hydrocarbon solvents (hexane, benzene, toluene, and p-xylene), which results in different outcomes. Reduction in hexane with an equivalent amount of KC8 generates the diiododialane [(Fc*(NHC)AlI)2], whereas complete reduction in hexane leads to an unusual C–H activation at an N–Me group of one NHC unit. In contrast, reaction in aromatic solvents result in hitherto unknown Birch-type reductions of the corresponding solvent molecules by transient aluminium radicals of the type [LAlR2]˙, which is ultimately bound to two aluminium centers.A bulky ferrocenyl-based NHC-stabilised aluminium(iii) dihalide was reduced in different solvents, leading to vastly different outcomes, including formation of a rare example of a dialane and a novel dialuminyl analogue of the Birch reduction. 相似文献
905.
Sarahi Pacheco-Espinoza Alejandro I. Cuesta-Balderas Jorge Vázquez-Lujano Abril Rosiles-Aguilera María A. Hernández-Pérez Felipe Cervantes-Sodi Fei Chen Qiang Shen Rong Tu Jorge R. Vargas-García Lian-Meng Zhang 《Particle & Particle Systems Characterization》2023,40(4):2200167
The development of new strategies for synthesizing 1D cerium oxide (CeO2) hollow nanostructures has attracted much attention in recent years due to the importance of their superior properties and highly anisotropic geometry. This study reports an unpublished route of fabricating novel multiwalled CeO2-δ nanotubes (CeO2-δ NTs) in which the entire volume of functionalized multiwalled carbon nanotubes (f-MWCNTs) is converted into the CeO2-δ pseudomorph through oxidation and dehydration topotactic reactions. The stable CeO2-δ (111) planes are topotactically grown on the curved C (002) planes, preferentially exposed along the nanotube axis. In their initial condition, the novel nanotubes consist of Ce oxyhydroxide (CeO2-x(OH)x) with residual carbon. When heating the air up to 500 °C, CeO2-x(OH)x transforms gradually by dehydration into CeO2-δ, while the residual carbon is oxidized. Despite compositional changes, nanotubes maintain their multiwalled structural integrity up to ≈550 °C. The CeO2-δ NTs exhibit an unusually high presence of Ce3+ ions and surface O vacancies, contributing to a low direct band gap ranging from 2.67 to 2.32 eV compared to their NPs counterparts (3.2 eV). 相似文献
906.
Juan C. Alfaro Juan A. Aledo José A. Gámez 《Mathematical Methods in the Applied Sciences》2023,46(1):7-27
The partial label ranking problem is a general interpretation of the preference learning scenario known as the label ranking problem, the goal of which is to learn preference classifiers able to predict a complete ranking with ties over the finite set of labels of the class variable. In this paper, we use unsupervised discretization techniques (equal-frequency and equal-width binning) to heuristically select the threshold for the numerical features in the algorithms based on induction of decision trees (partial label ranking trees algorithm). Moreover, we adapt the most well-known averaging (bootstrap aggregating and random forests) and boosting (adaptive boosting) ensemble methods to the partial label ranking problem, in order to improve the robustness of the built classifiers. We compare the proposed methods with the nearest neighbors-based algorithm (instance based partial label ranking) over the standard benchmark datasets, showing that our versions of the ensemble methods are superior in terms of accuracy. Furthermore, they are affordable in terms of computational efficiency. 相似文献
907.
José Felipe dos Santos Jonatas de Oliveira S. Silva José Fernando Macedo José Carlos S. Júnior Wandson S. Almeida Eliana Midori Sussuchi 《Electroanalysis》2023,35(9):e202200563
Estrone (E1) is associated with various health and environmental issues, necessitating the development of analytical methods for monitoring E1 in different matrices. In this context, the present study reports the development of a graphene quantum dot-based electrode (GQD/E) to detect estrone in water and urine samples. Voltammetric measurements under optimized conditions demonstrated the feasibility of using GQD/E to detect estrone at trace levels in aqueous samples. Two linear dynamic ranges were obtained at concentrations from 0.05 to 10.00 μmol L−1, with limit of detection (LOD) and quantification (LOQ) of 28.0 and 96.0 nmol L−1, respectively. Furthermore, the LOD value obtained in this study is one of the lowest ever reported in the literature for the electrochemical determination of E1. The method response showed no significant variation in the current intensity of E1 in the presence of the 16 interferents. The recovery values obtained by using GQD/E to quantify estrone in fortified samples of seawater, tap water, wastewater and synthetic urine ranged from 95.9 to 108.1 %, indicating that the method presents highly sensitive for detecting estrone in aqueous matrices. 相似文献
908.
Anna Broto-Ribas Sara Ruiz-Relaño Dr. Jorge Albalad Yunhui Yang Dr. Felipe Gándara Dr. Judith Juanhuix Dr. Inhar Imaz Prof. Dr. Daniel Maspoch 《Angewandte Chemie (International ed. in English)》2023,62(48):e202310354
Clip-off Chemistry is a synthetic strategy that our group previously developed to obtain new molecules and materials through selective cleavage of bonds. Herein, we report recent work to expand Clip-off Chemistry by introducing into it a retrosynthetic analysis step that, based on virtual extension of the products through cleavable bonds, enables one to define the required precursor materials. As proof-of-concept, we have validated our new approach by synthesising and characterising four aldehyde-functionalised Rh(II)-based complexes: a homoleptic cluster; a cis-disubstituted paddlewheel cluster; a macrocycle; and a crown. 相似文献
909.
Elgueta Elizabeth Becerra Yerko Martínez Ana Pereira Miguel Carrillo-Varela Isabel Sanhueza Felipe Nuñez Dariela Rivas Bernabé L. 《高分子科学》2023,41(6):874-886
Chinese Journal of Polymer Science - The adsorption capacity of hydrogels derived from modified xylan hemicellulose has been tested in order to develop new bio-based adsorbent materials useful for... 相似文献
910.
Airton Natanael Coelho Dias Carlos Alberto Tello Saenz Carlos Jos Leopoldo Constantino Cleber Jos Soares Felipe Ponciano Novaes Ana Maria Osrio Araya Balan 《Journal of Raman spectroscopy : JRS》2009,40(1):101-106
The zircon mineral is widely studied in geochronology. In the case of the fission track method (FTM), the age is determined by the density of fission tracks at the zircon surface, which can be observed with an optical microscope after an appropriate chemical treatment (etching). The etching must be isotropic at the zircon grain surface to be used in the FTM, which leads those zircon grains whose etching is anisotropic to be discarded. The only reason for this discarding is the nonuniform morphology of the surface grain seen by optical microscopy, that is, no further physicochemical analysis is performed. In this work, combining micro‐Raman and scanning electron microscopy (SEM) to study the etching anisotropy, it was shown that zircon grains that present at least one area at the surface where the density of fission track is uniform can be used in the FTM. The micro‐Raman showed characteristic spectra of the standard zircon sample either from the areas where there are tracks or from where there are not. The only difference found was in the Raman bandwidths, which were broader for the areas with higher density of fission tracks. This suggests simply a decrease in the relative percentage of the crystalline/amorphous phases at these areas. The SEM/energy dispersive spectrometry (EDX) showed that there were no significant differences in the principal chemical composition at the areas with and without fission tracks. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献