Coordination modes of hydrazone and acyl-hydrazone ligands containing a pyridine group with the {Re(CO)3}+ fragment

Financiado para publicación en acceso aberto: Universidade de Vigo/CISUGFour acyl-hydrazones derived from 5-hydroxypicolinohydrazide and 4-hydroxybenzaldehyde (HL11), 2-fluoro-4-hydroxybenzaldehyde (HL12), 2,4-dihydroxybenzaldehyde (HL13) or 2-pyridinecarboxaldehyde (HL14) and two hydrazones derived from 2-hydrazino pyridine and 4-dimethylaminobenzaldehyde (HL21) or 4-diethylamino-2-hydroxybenzaldehyde (HL22) were synthesized and their X-ray structures determined. Twelve rhenium(I) complexes of formula [ReX(HLn)(CO)3] (X = Cl, Br) were obtained by treating these ligands with [ReX(CH3CN)2(CO)3], and the structures of some representative compounds were determined by X-ray diffraction. The coordination geometry around rhenium(I) can be described as octahedral, with three carbon atoms in a fac configuration, the halogen atom and two nitrogen atoms from the hydrazone chain and the pyridine group, respectively. The carbonyl group of the acyl-hydrazone ligands does not participate in coordination in any of complexes HL11–HL14. The coordination mode of the ligands in all complexes could be established by comparing the IR and 1H NMR spectra. Formation of the hydrazonate complexes only proved possible with the derivatives of HL22. A study of the corresponding single crystal showed the presence of the dimer [Re2(L22)2(CO)6], in which the phenolate group of the ligand of the dimer partner coordinates to rhenium after deprotonation. This same group is used to bind to the rhenium atom of the dimer partner at the position released by the halide.Agencia Estatal de Investigación | Ref. PID2019-110218RB-I0

Aproximación del efecto de las coberturas cambiarias: un enfoque del sector empresarial colombiano.

El objeto de investigación busca determinar el impacto que tienen los derivados en la utilidad neta antes de impuestos de las empresas sujetas a riesgo cambiario en Colombia. Esperamos que los resultados nos indiquen una correlación positiva entre el margen utilidad antes de impuestos sobre ventas y el uso de coberturas cambiarias. Esto es, ante el uso de derivados ya sea de importación o exportación esperamos una menor fluctuación en el indicador descrito anteriormente. Este estudio es un primer paso para establecer por qué en Colombia la implementación de coberturas no impacta positivamente sobre el margen. De esta forma, podríamos determinar si las empresas realmente utilizan los derivados como coberturas y no como instrumentos de especulación. Por otro lado debe hacerse un análisis profundo de la política de cobertura de cada empresa para así poder determinar si las empresas que las aplican lo están haciendo de una manera acertada. Si se lograra llegar al nivel de detalle propuesto anteriormente, se podría tener una aproximación más precisa para responder la pregunta inicial.Introducción ; Objetivos ; Estado del arte ; Metodología ; Marco teórico ; Resultados esperados ; Conclusiones.Magíster en Finanzas Corporativa

Anharmonicity Reveals the Tunability of the Charge Density Wave Orders in Monolayer VSe2

VSe2 is a layered compound that has attracted great attention due to its proximity to a ferromagnetic state that is quenched by its charge density wave (CDW) phase. In the monolayer limit, unrelated experiments have reported different CDW orders with different transition temperatures, making this monolayer very controversial. Here we perform first-principles nonperturbative anharmonic phonon calculations in monolayer VSe2 in order to estimate the CDW order and the corresponding transition temperature. They reveal that monolayer VSe2 develops two independent charge density wave orders that compete as a function of strain. Variations of only 1.5% in the lattice parameter are enough to stabilize one order or the other. Moreover, we analyze the impact of external Lennard-Jones interactions, showing that these can act together with anharmonicity to suppress the CDW orders. Our results solve previous experimental contradictions, highlighting the high tunability and substrate dependency of the CDW orders of monolayer VSe2.We acknowledge the computational resources provided by the CESGA and the Aalto Science-IT project. A.O.F. acknowledges the financial support received through the Academy of Finland Project No. 349696. J.D. thanks the Department of Education of the Basque Government for a predoctoral fellowship (Grant No. PRE-2020-1-0220). We thank the Ministry of Science and Education of Spain for financial support through the projects PGC2018-101334-A-C22, GC2018-101334-B-C21, PID2021-122609NB-C22. I.E. acknowledges funding from the Department of Education, Universities and Research of the Eusko Jaurlaritza, and the University of the Basque Country UPV/EHU (Grant No. IT1527-22)

Morphology and Material Composition of the Mouthparts of Stromatium unicolor Olivier 1795 (Coleoptera: Cerambycidae) for Bionic Application

The novelty of this study is the deep analysis of the morphologic, geometric and mechanical performance of longhorn beetle larvae mouthparts. Furthermore, a metal nano identification of jaw reinforced parts was made. Background and Objectives: Analysis of insect mechanical properties has shown an important application in the develop of bionic technologies such as new materials, industrial machines and structural concepts. This study aims to determine the mechanical and geometric properties of longhorn beetle (Stromatium unicolor Olivier 1795) larvae mouthparts to improve the development of innovative cutting tools. In addition, this study obtains a nano identification of metals in the cuticle of the mouthparts, which will enable the development of new nontoxic and sustainable preservation agents against xylophagous insects based on nanoparticles. Materials and Methods: five third-larval-stage samples of Stromatium unicolor were used to study its mandible morphologic, geometric and mechanical properties. To this end, mouthparts were analyzed by several microscopic techniques using a scanning electron microscope, a stereomicroscope and an optical microscope. Composition analysis was performed using with two Analytical-Inca X-ray detectors, dispersive energy spectroscopy and dispersive wavelength spectroscopy. Results: The main geometric parameters of the insect jaw are the edge angle (β = 77.3°), maximum path depth of the insect (120 μm), length (800 µm) and mouthpart movement, which were identified and measured. The chemical analysis results of the jaw tissues shows the presence of zinc and manganese. Conclusions: The geometry and angles of the mouthparts can be applied in the fabrication of bionic self-sharpening cutting tools. Molecular compounds that form the reinforcing elements in the jaws can be used to develop wood preservatives based on nanometals and metal absorption and metabolism inhibitor

Acoustic detection and localisation system for Hylotrupes bajulus L. larvae using a MEMS microphone array

Producción CientíficaA novel system for acoustic detection of the presence of xylophagous insect larvae inside structural timber beams is presented. It is based on an extensive array of MEMS microphones that allows the acoustic detection and localisation of the larvae when they are active. In a first phase, the activity of the larvae is continuously detected by means of frequency filtering and a sliding energy estimator, and after that, a set of short-duration segmented signals is generated, which obtains the spatial localisation of the larvae, by means of a shaping algorithm based on delay-sum beamforming techniques. The tests carried out demonstrate that it is possible to detect and locate multiple larvae of Hylotrupes bajulus L. inside structural-sized pieces of wood of Pinus syilvestris L., as well as their internal trajectory. In the future, the system could address the identification of the specific type of xylophage responsible for the deterioration by using machine learning or equivalent techniques, based on the temporal and frequency information of the detected sound events. The aim of this work is to control unintentional infestions in the international timber trade, in the assembly and the use of infested timber and, in all cases, to be able to carry out selective, targeted and localised treatments and to verify their success.Junta de Castilla y León - UE-FEDER (VA228P20

Design and validation of a scalable, reconfigurable and low-cost structural health monitoring system

Producción CientíficaThis paper presents the design, development and testing of a low-cost Structural Health Monitoring (SHM) system based on MEMS (Micro Electro-Mechanical Systems) triaxial accelerometers. A new control system composed by a myRIO platform, managed by specific LabVIEW software, has been developed. The LabVIEW software also computes the frequency response functions for the subsequent modal analysis. The proposed SHM system was validated by comparing the data measured by this set-up with a conventional SHM system based on piezoelectric accelerometers. After carrying out some validation tests, a high correlation can be appreciated in the behavior of both systems, being possible to conclude that the proposed system is sufficiently accurate and sensitive for operative purposes, apart from being significantly more affordable than the traditional one.Junta de Castilla y León y Fondo Europeo de Desarrollo Regional (FEDER) - (grant VA095P17 and VA228P20

Alteration of platelet GPVI signaling in ST-elevation myocardial infarction patients demonstrated by a combination of proteomic, biochemical, and functional approaches

The platelet-specific collagen receptor glycoprotein VI (GPVI) is critical for the formation of arterial thrombosis in vivo. We analyzed GPVI-activated platelets from ST-elevation myocardial infarction (STEMI) patients and matched stable coronary artery disease (SCAD) controls in order to provide novel clues on the degree of involvement of GPVI signaling in the acute event. Firstly, platelets were isolated from systemic venous blood and activated with the GPVI specific agonist CRP (collagen-related peptide). STEMI and SCAD samples were compared by a phosphoproteomics approach. Validations were by immunoblotting in systemic and intracoronary blood from independent cohorts of patients. Twenty-six differentially regulated proteins were identified when comparing CRP-activated systemic platelets from STEMI and SCAD patients, 4 of which were selected for validation studies: PLCɣ2, G6f, SLP-76, and Dok-2. Immunoblot analyses showed these four proteins had higher tyrosine phosphorylation levels in response to CRP in platelets from STEMI patients, being these levels more pronounced at the culprit site of coronary artery occlusion. Moreover, platelet aggregation studies showed a higher response to GPVI agonists in STEMI patients compared to SCAD controls. In conclusion, we show an altered activation state of GPVI signaling in STEMI patients, confirming this receptor as a promising anti-thrombotic target for myocardial infarctionhis work was supported by the Spanish Ministry of Economy and Competitiveness (MINECO) [grant No. SAF2013-45014-R, co-funded by the European regional development fund (ERDF)]. AG acknowledges support from the Sociedad Española de Trombosis y Hemostasia – Fundación Española de Trombosis y Hemostasia (SETH-FETH). PV is a predoctoral fellow from the Instituto de Investigación Sanitaria de Santiago (IDIS)S

Variations in platelet proteins associated with st-elevation myocardial infarction: Novel clues on pathways underlying platelet activation in acute coronary syndromes

OBJECTIVE: Our aim in this study was to provide novel information on the molecular mechanisms playing a major role in the unwanted platelet activation associated with ST-elevation myocardial infarction (STEMI). METHODS AND RESULTS: We compared the platelet proteome of 11 STEMI patients to a matched control group of 15 stable chronic ischemic cardiopathy patients. In addition, we did a prospective study to follow the STEMI patients over time. Proteins were separated by high-resolution 2D gel electrophoresis, identified by mass spectrometry, and validated by Western blotting. Platelets from STEMI patients on admission displayed 56 protein spot differences (corresponding to 42 unique genes) compared with the control group. The number of differences decreased with time during the patients' follow-up. Interestingly, the adapter protein CrkL and the active form of Src (phosphorylated in Tyr418) were found to be upregulated in platelets from STEMI patients. Major signaling pathways related to the proteins identified include integrin, integrin-linked kinase, and glycoprotein VI (GPVI) signaling. Interestingly, a study on an independent cohort of patients showed a higher degree of activation of GPVI signaling in STEMI patients. CONCLUSIONS: CrkL, the active form of Src, and GPVI signaling are upregulated in platelets from STEMI patients

Assessment of machine learning algorithm-based grading of Populus x euramericana I-214 structural sawn timber

The efficiency of visual grading standards applied to structural timber is often inappropriate, and timber properties are either under or over-graded. Although not included in the current UNE 56544 visual grading standard, machine learning algorithms represent a promising alternative to grade structural timber. The general aim of this research was to compare the performance of machine learning algorithms based on visual defects, non-destructive techniques and sawing systems (“cut type”) with UNE 56544:1997 visual grading in order to predict the qualifying efficiency of Populus x euramericana I-214 structural timber. Visual evaluation, ultrasound and vibrational non-destructive testing, and sawing systems register (radial, tangential and mixed) were applied to characterize 945 beams. In addition, in order to retrieve actual physical-mechanical values, density and static bending destructive testing (EN-408:2011 + A1:2012) was also carried out. Several machine learning algorithms were then used to grade the beams, and their predictive accuracy was compared with that of visual grading. To do so, three scenarios were considered: a first scenario in which only visual variables were used; a second scenario in which “cut type” variables were also included; and a third scenario in which additional non-destructive variables were considered. Results showed a poor level of performance of UNE 56544:1997, with an apparent mismatch between the strength values assigned for each visual grade (established by the EN 338 standard) and the actual values. On the opposite, all algorithms performed better than visual grading and may thus be deemed as promising timber strength grading tools.Junta de Castilla y León (project VA047A08

Effect of scrapie prion infection in ovine bone marrow-derived mesenchymal stem cells and ovine mesenchymal stem cell-derived neurons

Scrapie is a prion disease affecting sheep and goats and it is considered a prototype of transmissible spongiform encephalopathies (TSEs). Mesenchymal stem cells (MSCs) have been proposed as candidates for developing in vitro models of prion diseases. Murine MSCs are able to propagate prions after previous mouse-adaptation of prion strains and, although ovine MSCs express the cellular prion protein (PrPC), their susceptibility to prion infection has never been investigated. Here, we analyze the potential of ovine bone marrow-derived MSCs (oBM-MSCs), in growth and neurogenic conditions, to be infected by natural scrapie and propagate prion particles (PrPSc) in vitro, as well as the effect of this infection on cell viability and proliferation. Cultures were kept for 48–72 h in contact with homogenates of central nervous system (CNS) samples from scrapie or control sheep. In growth conditions, oBM-MSCs initially maintained detectable levels of PrPSc post-inoculation, as determined by Western blotting and ELISA. However, the PrPSc signal weakened and was lost over time. oBM-MSCs infected with scrapie displayed lower cell doubling and higher doubling times than those infected with control inocula. On the other hand, in neurogenic conditions, oBM-MSCs not only maintained detectable levels of PrPSc post-inoculation, as determined by ELISA, but this PrPSc signal also increased progressively over time. Finally, inoculation with CNS extracts seems to induce the proliferation of oBM-MSCs in both growth and neurogenic conditions. Our results suggest that oBM-MSCs respond to prion infection by decreasing their proliferation capacity and thus might not be permissive to prion replication, whereas ovine MSC-derived neuron-like cells seem to maintain and replicate PrPSc