Dendrímeros: Macromoléculas versátiles con interés interdisciplinar.

Los dendrímeros son una clase especial de polímeros que presentan estructuras bien definidas, altamente ramificadas en su interior y con numerosos grupos funcionales en la superficie. La posibilidad de controlar su constitución química e incorporar diferentes grupos funcionales en posiciones específicas ha llevado a que las moléculas dendríticas ofrezcan un abanico de nuevas propiedades y aplicaciones que les confiere un importante y reconocido interés interdisciplinar en áreas tan diversas como son la química inorgánica, orgánica, analítica, la biología, el diseño de nuevos materiales, la farmacología, la nanotecnología, etcétera. En este artículo proporcionamos una visión muy general de este tipo de macromoléculas, su estructura, métodos de síntesis y algunas de sus aplicacione

Electrocatalytic self-assembled multilayer structures based on thiolated Fc-DAB dendrimers: Determination of heavy metal ions by enzymatic inhibition

The development of sensitive and rapid inhibition-based biosensors for monitoring trace levels of heavy metals such as lead and copper ions in environmental samples is of high interest. In this work, we describe the fabrication of HRP sensitive peroxide biosensors based on ferrocenyl thiolated DAB dendrimers as bonding-layer between electrodeposited and colloidal gold nanoparticles and compare their electrocatalytic properties with those of thiolated DAB homologues. The complete electrochemical, kinetic and analytical characterization of these new heavy metals’ inhibition-biosensors are investigate

Optical and physicochemical characterizations of a cellulosic/CdSe-QDs@S-DAB5 film

CdSe quantum dots nanoparticles were coated with the thiolated (DiAminoButane based dendrimer) DAB dendrimer of fifth generation (S-DAB(5)) and embedded in a highly hydrophilic regenerated cellulose (RC) film by simple dip-coating method (immersion in QD-dendrimer aqueous solution) as a way to get a flexible nano-engineered film (RC-4/CdSe-QDs@S-DAB(5)) with high transparency and photoluminescence properties for different applications. Optical changes in the RC film associated with QDs inclusion were determined by spectroscopic ellipsometry (SE) measurements, which provide information on changes caused in the refraction index and the extinction coefficients of the film, as well as by light transmittance/reflectance curves and photoluminescence (PL) spectra. Impedance spectroscopy (IS) and other typical physicochemical techniques for material characterization (TEM, SEM and XPS) have also been used in order to have more complete information on film characteristics. A comparison of RC-4/CdSe-QDs@S-DAB(5) film optical characteristics with those exhibited by other RC-modified films depending on the type of dendrimer was also carried out

Electrochemical and bioelectrocatalytical properties of novel block-copolymers containing interacting ferrocenyl units

The electrochemical characterization of three different polystyrene-b-polybutadiene block copolymers functionalized with ferrocenyl units electronically communicated, PSm-PBn(HSiMeFc2)p where m=615, n=53, p=39 (1), m=375, n=92, p=76 (2) and m=455, n=204, p=170 (3), has been carried out both in solution and electrochemically deposited onto platinum electrodes. The bioelectrocatalytical properties of electrodes modified with the polymers in the nicotinamide dinucleotide (NADH) and glucose oxidase (GOx) oxidations have been investigated as a function of the constitution and structure of the polymers. The analytical properties of electrodes modified with these polymers as sensors of NADH and GOx are described. In addition, an amperometric biosensor for glucose, prepared by electrostatic immobilization of glucose oxidase onto a platinum electrode modified with one of the ferrocenyl block copolymers as an example, has been developed. The results confirm that electrodes modified with the examined copolymers act as efficient redox mediators for the electrocatalytic oxidation of both reduced nicotinamide dinucleotide cofactor and glucose oxidase. The reaction with NADH proceeds via formation of a charge-transfer intermediate before yielding the reaction products. This is a novel example of electrodes modified with ferrocene derivatives that can be applied to the determination of NADH without the use of diaphorase. The redox copolymers co-immobilized with glucose-oxidase have been successfully used as amperometric biosensors for glucose determinations. As expected these compounds allow using lower working potentials. The sensitivities and detection limits obtained are comparable or even better than those of other ferrocene-modified polymers mediator electrodes

Skin irritation potential of graphene-based materials using a non-animal test

Graphene related materials, if prepared with non-irritant exfoliation agents, do not induce skin irritation on a 3D model of human epidermis, following the OECD guideline 439

Does environmental risk really change in abandoned mining areas in the medium term when no control measures are taken?

Studies regarding how environmental risk evolves in abandoned mining areas in the medium term have been seldom carried out. The answer to this question is not obvious despite it is essential in order to evaluate the need to take urgent control measures in these areas. Fifty-two samples corresponding to soils (from natural pasture and arable lands) and mine tailings were collected in the surroundings of an old Spanish Pb/Zn mine (San Quintín, Central Spain). Current concentrations of pseudo-total and available metal (loid)s (Pb, Zn, Cd, Cu, As and Ag) were determined and the environmental risk assessment (ERA) was conducted with these data and those corresponding to a sampling previously carried out in 2006. ERA was carried out by calculating the geoaccumulation index (Igeo), the pollution load index (PLI) and the potential ecological risk index (PER). Results demonstrated that Pb and Zn concentrations have increased in the soils of the plots surrounding the mining areas causing a moderate rise in most of the determined pollution indices between 2006 and 2020. It was especially significant in the pastureland areas, with increases up to 17% in the number of soil samples that reached the highest risk classification in 2020 as compared to those taken in 2006. The results obtained here demonstrate that the environmental risk can actually increase in a continuous way in abandoned mining areas despite the closure of the mining operation and the effect of the possible natural attenuation.Pocas veces se han realizado estudios sobre cómo evoluciona el riesgo ambiental en áreas mineras abandonadas a mediano plazo. La respuesta a esta pregunta no es obvia, aunque es fundamental para evaluar la necesidad de tomar medidas urgentes de control en estas áreas. Se recogieron 52 muestras correspondientes a suelos (de pastos naturales y tierras de cultivo) y relaves de mina en el entorno de una antigua mina española de Pb/Zn (San Quintín, Centro de España). Se determinaron las concentraciones actuales de metales (loid)s pseudototales y disponibles (Pb, Zn, Cd, Cu, As y Ag) y con estos datos y los correspondientes a un muestreo realizado previamente se realizó la evaluación de riesgo ambiental (ERA). en 2006. ERA se realizó calculando el índice de geoacumulación(Igeo), el índice de carga contaminante (PLI) y el índice de riesgo ecológico potencial (PER). Los resultados demostraron que las concentraciones de Pb y Zn han aumentado en los suelos de las parcelas aledañas a las zonas mineras provocando un aumento moderado en la mayoría de los índices de contaminación determinados entre 2006 y 2020. Fue especialmente significativo en las zonas de pastoreo, con incrementos de hasta el 17%. en el número de muestras de suelo que alcanzaron la clasificación de mayor riesgo en 2020 en comparación con las tomadas en 2006. Los resultados aquí obtenidos demuestran que el riesgo ambiental puede aumentar de manera continua en áreas mineras abandonadas a pesar del cierre de la operación minera y el efecto de la posible atenuación natural

Upgrade of a climate service tailored to water reservoirs management

We present the upgrade of a web tool designed to help in the decision making process for water reservoirs management in Spain. The tool, called S-ClimWaRe (Seasonal Climate predictions in support of Water Reservoirs management), covers the extended winter season (from November to March), when the North Atlantic Oscillation (NAO) pattern strongly influences the hydrological interannual variability in South-Western Europe. This climate service is fully user driven, and aims at meeting their requirements incorporating recent scientific progress.The research leading to these results has received funding from the MEDSCOPE project co-funded by the European Commission as part of ERA4CS, an ERA-NET initiated by JPI Climate, grant agreement 690462

Upgrade of a climate service tailored to water reservoirs management

Presentación realizada en: EMS Annual Meeting (2021) celebrado de forma virtual del 3 al 10 de septiembre de 2021.In this paper we present the upgrade of a web tool designed to help in the decision making process for water reservoirs management in Spain. The tool, called S-ClimWaRe (Seasonal Climate predictions in support of Water Reservoirs management) is organized in two main displaying panels. The first one -diagnostic panel- allows the user to explore, for any water reservoir or grid point over continental Spain, the existing hydrological variability and risk linked to climate variability. The second one -forecasting panel- provides probabilistic seasonal predictions for some variables of interest. Following users’ need the tool initially covers the extended winter season (from November to March), when the North Atlantic Oscillation pattern strongly influences the hydrological interannual variability in South-Western Europe. This climate service is fully user driven with a strong commitment of users and stakeholders that has allowed continuous improvement of this tool, meeting users requirements and incorporating latest scientific progress

Prevalence and severity of renal dysfunction among 1062 heart transplant patients according to criteria based on serum creatinine and estimated glomerular filtration rate: results from the CAPRI study

[Abstract] Chronic kidney disease (CKD) is staged on the basis of glomerular filtration rate; generally, the MDRD study estimate, eGFR, is used. Renal dysfunction (RD) in heart transplant (HT) patients is often evaluated solely in terms of serum creatinine (SCr). In a cross-sectional, 14-center study of 1062 stable adult HT patients aged 59.1 ± 12.5 yr (82.3% men), RD was graded as absent-or-mild (AoM), moderate, or severe (this last including dialysis and kidney graft) by two classifications: SCr-RD (SCr cutoffs 1.6 and 2.5 mg/dL) and eGFR-RD (eGFR cutoffs 60 and 30 mL/min/1.73 m2). SCr-RD was AoM in 68.5% of patients, moderate in 24.9%, and severe in 6.7%; eGFR-RD, AoM in 38.6%, moderate in 52.2%, severe in 9.2%. Among patients evaluated 9.5 yr post-HT (the periods defined by time-since-transplant quartiles), AoM/moderate/severe RD prevalences were 9.5, SCr-RD 58/32/10%, eGFR-RD 32/52/16%. The prevalence of severe RD increases with time since transplant. If the usual CKD stages are appropriate for HT patients, the need for less nephrotoxic immunosuppressants and other renoprotective measures is greater than is suggested by direct SCr-based grading, which should be abandoned as excessively insensitive