Supramolecular protection from the enzymatic tyrosine phosphorylation in a polypeptide

Here we report two new artificial pseudopeptidic cages that bind the EYE peptide epitope in pure water at physiological pH (as studied by fluorescence and NMR spectroscopies). The supramolecular complexation of the Tyr residues efficiently precludes their subsequent PTK-catalysed phosphorylation. Our results show a supramolecular modulation of the PTK activity by competitive substrate caging.This work was supported by MINECO/FEDER (CTQ2012-38543-C03, CTQ2015-68429-R and CTQ2015-70117-R projects) and Generalitat de Catalunya (AGAUR, 2014 SGR 231)

Photoinduced Proton and Charge Transfer in 2‑(2′- Hydroxyphenyl)imidazo[4,5‑b]pyridine

This is the peer-reviewed version of the following article: The Journal of Physical Chemistry B 2013, 117, 884–896, DOI: 10.1021/jp311709c, which has been published in final form at https://pubs.acs.org/doi/abs/10.1021/jp311709c. This article may be used for non-commercial purposes onlyThis paper deals with the interplay between solvent properties and isomerism of 2-(2′-hydroxyphenyl)imidazo[4,5-b]pyridine (1), and the proton and charge-transfer processes that the different isomers undergo in the first-excited singlet state. We demonstrate the strong influence of these processes on the fluorescence properties of 1. We studied the behavior of 1 in several neutral and acidified solvents, by UV–vis absorption spectroscopy and by steady-state and time-resolved fluorescence spectroscopy. The fluorescence of 1 showed a strong sensitivity to the environment. This behavior is the result of conformational and isomeric equilibria and the completely different excited-state behavior of the isomers. For both neutral and cationic 1, isomers with intramolecular hydrogen bond between the hydroxyl group and the benzimidazole N undergo an ultrafast excited-state intramolecular proton transfer (ESIPT), yielding tautomeric species with very large Stokes shift. For both neutral and cationic 1, isomers with the OH group hydrogen-bonded to the solvent behave as strong photoacids, dissociating in the excited state in solvents with basic character. The pyridine nitrogen exhibits photobase character, protonating in the excited state even in some neutral solvents. An efficient radiationless deactivation channel of several species was detected, which we attributed to a twisted intramolecular charge-transfer (TICT) process, facilitated by deprotonation of the hydroxyl group and protonation of the pyridine nitrogenThis work has been supported by the Spanish Government and the European Regional Development Fund (Grant CTQ2010-17835) and the Xunta de Galicia (Grant CN 2012/314). A.B., M.V., and J.L.P.L. are thankful for a “Fundación Segundo Gil Dávila” fellowship, a MEC-FPU fellowship, and a “Ramon y Cajal” contract, respectivelyS

Design of beams and slabs of self-compacting concrete fittings working to flexion

Numerous experimental studies indicate that addition of fibers substantially increases the shear strength of concrete and mortar beams, and that stirrups and reinforcing fibers combination can be really effective. When steel fibers are used as a supplement or substitute for vertical stirrups or folded bars, we obtain the following characteristics: The fibers are distributed randomly by the volume of the concrete with a closer separation than can be achieved with the Armor; The tensile strength at first crack, the ultimate tensile strength and the shear friction resistance are increased

Moderately Strong Photoacid Dissociates in Alcohols with High Transient Concentration of the Proton-Transfer Contact Pair

This is the peer-reviewed version of the following article: The Journal of Physical Chemistry Letters 2014, 5, 989–994, DOI: 10.1021/jz5001648, which has been published in final form at https://pubs.acs.org/doi/abs/10.1021/jz5001648. This article may be used for non-commercial purposes onlyProton transfer from strong photoacids to hydroxylic solvents is much under debate. Experimentally, the main issue stems from relaxation and diffusion processes that are concomitant with ultrafast proton transfer and blur population dynamics. To overcome this, we propose a fast photodissociation reaction that, however, proceeds slower than solvent relaxation. Fluorescence spectroscopy of the cationic photoacid 2-(1′-hydroxy-2′-naphtyl)benzimidazolium reveals a two-stage mechanism: (a) reversible elementary proton transfer inside the solvent shell and (b) irreversible contact-pair splitting. The time evolution of the fluorescence signal is complex, yet this is explained quantitatively by simultaneous, spectrally overlapping emission of the acid, the conjugate base, and the contact proton-transfer pair. The latter attains high transient concentration in linear alcohols. Microscopic rate constants of dissociation are determinedWe thank the Spanish Government and the European Regional Development Fund (Grants CTQ2010-17835 and CTQ2010-17026) and the Xunta de Galicia (Grants CN 2012/314,EM2012/091, and GPC2013/052) for financial support of our work. J.L.P.L. thanks the Spanish Ministry of Economy and Competitiveness for funding through the Ramón y Cajal Programm 2009. M.V.G. and A.B. thank the Spanish Government and the “Segundo Gil-Dávila” Foundation, respectively, for financial supportS

Novel potential scaffold for periodontal tissue engineering.

Objective: Characterization of novel calcium and zinc loaded electrospun matrices for periodontal regeneration. Materials and Methods: A polymethylmetacrylate-based membrane was calcium or zinc loaded. Matrices were characterized morphologically by atomic force and scanning electron microscopy, and mechanically probed by a nanoindenter. Biomimetic calcium phosphate precipitation on polymeric tissues was assessed. Cell viability tests were performed using oral mucosa fibroblasts. Data were analyzed by Kruskal-Wallis and Mann-Whitney tests or by ANOVA and Student- Newman-Keuls multiple comparisons. Results: Zinc and calcium loading on matrices did not modify their morphology but increased nanomechanical properties and decreased nanoroughness. Precipitation of calcium and phosphate on the matrices surfaces was observed in zinc-loaded specimens. Matrices were found to be non-toxic to cells in all the assays. Calcium and zinc-loaded scaffolds presented a very low cytotoxic effect. Conclusions: Zinc-loaded membranes permit cells viability and promoted mineral precipitation in physiological conditions. Based on the tested nanomechanical properties and scaffold architecture, the proposed membranes may be suitable for cell proliferation. Clinical Relevance: The ability of zinc-loaded matrices to promote precipitation of calcium phosphate deposits, together with their observed non-toxicity and its surface chemistry allowing covalent binding of proteins, may offer new strategies for periodontal regeneration.Project MAT2014-52036-P supported by the Ministry of Economy and Competitiveness (MINECO) and European Regional Development Fund (FEDER)

Dissociation of a Strong Acid in Neat Solvents: Diffusion Is Observed after Reversible Proton Ejection Inside the Solvent Shell

This is the peer-reviewed version of the following article: The Journal of Physical Chemistry B 2013, 117, 14065–14078, DOI: 10.1021/jp4042765, which has been published in final form at https://pubs.acs.org/doi/abs/10.1021/jp4042765. This article may be used for non-commercial purposes onlyStrong-acid dissociation was studied in alcohols. Optical excitation of the cationic photoacid N-methyl-6-hydroxyquinolinium triggers proton transfer to the solvent, which was probed by spectral reconstruction of picosecond fluorescence traces. The process fulfills the classical Eigen–Weller mechanism in two stages: (a) solvent-controlled reversible dissociation inside the solvent shell and (b) barrierless splitting of the encounter complex. This can be appreciated only when fluorescence band integrals are used to monitor the time evolution of the reactant and product concentrations. Band integrals are insensitive to solvent dynamics and report relative concentrations directly. This was demonstrated by first measuring the fluorescence decay of the conjugate base across the full emission band, independently of the proton-transfer reaction. Multiexponential decay curves at single wavelengths result from a dynamic red shift of fluorescence in the course of solvent relaxation, whereas clean single exponential decays are obtained if the band integral is monitored instead. The extent of the shift is consistent with previously reported femtosecond transient absorption measurements, continuum theory of solvatochromism, and molecular properties derived from quantum chemical calculations. In turn, band integrals show clean biexponential decay of the photoacid and triexponential evolution of the conjugate base in the course of the proton transfer to solvent reaction. The dissociation step follows the slowest stage of solvation, which was measured here independently by picosecond fluorescence spectroscopy in five aliphatic alcohols. Also, the rate constant of the encounter-complex splitting stage is compatible with proton diffusion. Thus, for this photoacid, both stages reach the highest possible rates: solvation and diffusion control. Under these conditions, the concentration of the encounter complex is substantial during the earliest nanosecondWe thank the Spanish Government and the European Regional Development Fund (grant nos. CTQ2010-17835, CTQ2010-17026, and CTQ2011-29311-C02-01) and the Xunta de Galicia (grants nos. CN 2012/314, 2012-PG237, GPC2013/052 and INCITE09 314 252 PR) for financial support of our work. J.L.P.L. thanks the Spanish Ministry of Economy and Competitiveness for funding through the Ramon y Cajal ́ Programm 2009. M.V. and C.C.B. thank the Spanish Government for funding through the FPU program. A. B. thanks the Segundo Gil Dávila Foundation for financial supportS

PLATAFORMAS PARA CONTROLADOR ACTIVO LINEAL APLICADO A LA DIRECCIÓN ASISTIDA AUTOMOTRIZ (PLATFORMS FOR LINEAR ACTIVE CONTROLLER APPLIED TO THE AUTOMOTIVE ASSISTED STEERING)

En este artículo se muestra un problema clásico en la teoría de control, el cual es el diseño de una ley de retroalimentación, teniendo el propósito de que la salida de cualquier sistema siga asintóticamente una señal de referencia. En este trabajo, se pretende que la velocidad lateral siga a una maniobra del conductor, pero en sentido contrario. Se propone que el vehículo se encuentra realizando pruebas de manejo conocidas por norma internacional ISO 7401, por ende el problema de la teoría de regulación lineal vía retroalimentación de estados por medio de una función de Lyapunov es la solución idónea a nuestro problema ya que se supone la medición de la velocidad angular de viraje. Los actuadores que integraremos en este artículo serán los frenos () y el sistema frontal activo (AFS, por sus siglas en inglés), por medio de la simulación de Matlab-Simulink-CarSim y una plataforma propia.Palabra(s) clave: Retroalimentación de estados, velocidad lateral, velocidad angular de viraje, CarSim. AbstractThis article shows a classic problem of control theory, which is the design of a feedback law, it has the purpose that the output of any system follows a reference signal asymptotically. In this paper we aim that the lateral velocity follows a drivers´s maneuver, but in the opposite direction. It is proposed that the vehicle performs driving test knowed by the ISO 7401 international standard, thus, to solve this problem we are going to use the feedback-state lineal theory by means of a Lyapunov function, because it is supposed to measure the yaw velocity. The actuators that we will be integrating in this paper, will be the brakes () and Front Active System (AFS), through simulations in Matlab- Simulink-CarSim and own platform.Keywords: Feedback state, lateral velocity, yaw velocity, CarSim

Evaluation of Prescribed Fires from Unmanned Aerial Vehicles (UAVs) Imagery and Machine Learning Algorithms

Producción CientíficaPrescribed fires have been applied in many countries as a useful management tool to prevent large forest fires. Knowledge on burn severity is of great interest for predicting post-fire evolution in such burned areas and, therefore, for evaluating the efficacy of this type of action. In this research work, the severity of two prescribed fires that occurred in “La Sierra de Uría” (Asturias, Spain) in October 2017, was evaluated. An Unmanned Aerial Vehicle (UAV) with a Parrot SEQUOIA multispectral camera on board was used to obtain post-fire surface reflectance images on the green (550 nm), red (660 nm), red edge (735 nm), and near-infrared (790 nm) bands at high spatial resolution (GSD 20 cm). Additionally, 153 field plots were established to estimate soil and vegetation burn severity. Severity patterns were explored using Probabilistic Neural Networks algorithms (PNN) based on field data and UAV image-derived products. PNN classified 84.3% of vegetation and 77.8% of soil burn severity levels (overall accuracy) correctly. Future research needs to be carried out to validate the efficacy of this type of action in other ecosystems under different climatic conditions and fire regimes.Ministerio de Economía, Industria y Competitividad - Fondo Europeo de Desarrollo Regional (project AGL2017-86075-C2-1-R)Junta de Castilla y León (project LE001P17

Bolaform surfactant‐induced Au nanoparticle assemblies for reliable solution‐based surface‐enhanced Raman scattering detection

Financiado para publicación en acceso aberto: Universidade de Vigo/CISUGSolution-based surface-enhanced Raman scattering (SERS) detection typically involves the aggregation of citrate-stabilized Au nanoparticles into colloidal assemblies. Although this sensing methodology offers excellent prospects for sensitivity, portability, and speed, it is still challenging to control the assembly process by a salting-out effect, which affects the reproducibility of the assemblies and, therefore, the reliability of the analysis. This work presents an alternative approach that uses a bolaform surfactant, B20, to induce the plasmonic assembly. The decrease of the surface charge and the bridging effect, both promoted by the adsorption of B20, are hypothesized as the key points governing the assembly. Furthermore, molecular dynamic simulations supported the bridging effect of the B20 by showing the preferential bridging of surfactant monomers between two adjacent Au(111) slabs. The colloidal assemblies showed excellent SERS capabilities towards the rapid, on-site detection and quantification of beta-blockers and analgesic drugs in the nanomolar regime, with a portable Raman device. Interestingly, the application of state-of-the-art convolutional neural networks, such as ResNet, allows a 100% accuracy in classifying the concentration of different binary mixtures. Finally, the colloidal approach was successfully implemented in a millifluidic chip allowing the automation of the whole process, as well as improving the performance of the sensor in terms of speed, reliability, and reusability without affecting its sensitivity.MCIN/AEI/10.13039/501100011033 | Ref. PID2019-108954RB-I00MCIN/AEI/10.13039/501100011033 | Ref. PID2019-106960GB-I00MCIN/AEI/10.13039/501100011033 | Ref. BES-2017-08167MEC/AEI | Ref. CTQ2017-84354-PXunta de Galicia | Ref. GRC ED431C 2020/09Xunta de Galicia | Ref. GR 2007/08

Single and combined effects of regulated and emerging mycotoxins on viability and mitochondrial function of SH-SY5Y cells

Co-occurrence of emerging and regulated mycotoxins in contaminated samples has been widely documented, but studies about their combined toxicity are scarce. In this report, the regulated mycotoxins deoxynivalenol, fumonisin B1 and zearalenone, and the emerging ones enniatin A, enniatin B and beauvericin were tested in SH-SY5Y human neuroblastoma cells. Their individual and binary combined effects on cell viability and mitochondrial function were evaluated. The results with individual mycotoxins revealed that deoxynivalenol and emerging mycotoxins were the most damaging to neuronal cells, presenting IC50 values between 0.35 and 2.4 μM. Interestingly, non-regulated mycotoxins triggered apoptosis by affecting to mitochondrial membrane potential. However, when regulated and non-regulated mycotoxins were binary mixed, antagonistic effects were found in all cases. Finally, cow feed and milk extracts were analysed by UHPLC-MS/MS, detecting the presence of several mycotoxins included in this study. These extracts were tested in neuroblastoma cells, and damaging effects on cell viability were found. Although binary combinations of mycotoxins produced antagonistic effects, their mixture in natural matrixes induces greater effects than expected. Therefore, it would be interesting to explore the matrix influence on mycotoxin toxicity, and to continue studying the neurotoxic mechanism of action of emerging mycotoxins, as they could be a health hazardThe research leading to these results has received funding from the following FEDER cofunded grants. From Consellería de Cultura, Educación e Ordenación Universitaria, Xunta de Galicia, 2017 GRC GI-1682 (ED431C 2017/01). From Ministerio de Ciencia e Innovación IISCIII/PI19/001248. From European Union Interreg Alertox-Net EAPA-317-2016, Interreg Agritox EAPA-998-2018, and H2020 778069-EMERTOXS