Soluble polythiophenes as anticorrosive additives for marine epoxy paints

This study compares the resistance against corrosion of a marine epoxy primer modified with Zn-3(PO4)(2) (10 wt%) or a small concentration (0.3 wt%) of conducting polymer (CP) as inorganic or organic anticorrosive pigment, respectively. More specifically, the behavior of three different CPs has been evaluated: polyaniline (PAni) emeraldine base, poly(3-thiophen-3-yl-acrylic acid methyl ester) and poly(2-thiophen-3-yl-malonic acid dimethyl ester), the latter two being soluble polythiophene (PTh) derivatives bearing carboxylate side groups. In a first stage, the structural, thermal, and mechanical properties of all the modified epoxy coatings were characterized using infrared spectroscopy, thermogravimetric analyses and stress-strain assays, respectively. After this, accelerated corrosion assays have evidenced that the degree of protection imparted by a small concentration of PAni is higher than that obtained using 10wt% of Zn-3(PO4)(2). Indeed, PAni has been found to be more effective as anticorrosive additive than the two PTh derivatives. This fact has been attributed to the electroactivity of the former, which is higher than that of the latter. Thus, the ability to store charge has been proposed to be also responsible of protection against corrosion imparted by organic additives, based on CPs.Peer ReviewedPostprint (author’s final draft

Estudio comparativo de la estabilización de un suelo plastico con cal y/o cemento portland

En este trabajo se comentan las determinaciones practicadas en la estabilización de un suelo plástico con cemento portland y con cal hidratada en polvo, así como la estabilización de dicho suelo con cemento portland, previa corrección con cal, Los gráficos muestran los resultados obtenidos en dicha estabilización. Se comentan los posibles procesos físico-químicos que tendrían lugar entre el suelo y los estabilizantes, para dar lugar a la mencionada estabilización.The present repot refers to the determinations made over one plastic soil, estahilized with portlandcement and with hidrated lime, as soon as the stabilization of the same soil with Portland cement, foregoing corrected with hidrated lime. The graphs includes the results obtained in these determinations. The work contains some ideas on the physicochemical proccesses that would explains the mentioned stabilization

The environment as a common good in the time of globalization: its conceptualization and social perception

Landscape, Law & Justice: Proceedings from a workshop on old and new cornmons, Centre for Advanced Study, Oslo, 11-13 March 2003.It is usual to consider lhe environment as a common good, but we are far from having a clear definition of either of lhem: lhe environment and lhe common. Bolh vary according the scope of lhe analysis (world, national, regional, provincial, local), the different societies, and the diverse elements included, and so vary the social perception and action on the environment. On the other hand, new and increasing demands from lhe environment as a common good, as it is the case of preserving biodiversity or landscape among others) might clash with traditional commons. Societies face now a challenge to compatibilize traditional cornmons and the new common: the environment. In arder to study lhe idea of the environment as the new common is relevant to pay attention to legal conceptions and issues related with property rights. A conceptual and historical clarification of the sense and meaning of common is required. In this paper the conceptual problematic of lhe term common for the case of the environment is analyzed, and the change in its social perception within the process of industrialization and globalization. A case study of Navarre (Spain) show how peapie conceive Nature in terms of common good

α‐Functionalization of imines via visible light photoredox catalysis

The innate electrophilicity of imine building blocks has been exploited in organic synthetic chemistry for decades. Inspired by the resurgence in photocatalysis, imine reactivity has now been redesigned through the generation of unconventional and versatile radical intermediates under mild reaction conditions. While novel photocatalytic approaches have broadened the range and applicability of conventional radical additions to imine acceptors, the possibility to use these imines as latent nucleophiles via single‐electron reduction has also been uncovered. Thus, multiple research programs have converged on this issue, delivering creative and practical strategies to achieve racemic and asymmetric α‐functionalizations of imines under visible light photoredox catalysisThis research was funded by the European Research Council, grant number 647550; the Spanish Government, grant number RTI2018-095038-B-I00; the “Comunidad de Madrid” and European Structural Funds, grant number S2018/NMT-436

Self-assembly of Fmoc-tetrapeptides based on the RGDS cell adhesion motif

Self-assembly in aqueous solution has been investigated for two Fmoc [Fmoc ¼ N-(fluorenyl)-9-methoxycarbonyl] tetrapeptides comprising the RGDS cell adhesion motif from fibronectin or the scrambled sequence GRDS. The hydrophobic Fmoc unit confers amphiphilicity on the molecules, and introduces aromatic stacking interactions. Circular dichroism and FTIR spectroscopy show that the self-assembly of both peptides at low concentration is dominated by interactions among Fmoc units, although Fmoc-GRDS shows b-sheet features, at lower concentration than Fmoc-RGDS. Fibre X-ray diffraction indicates b-sheet formation by both peptides at sufficiently high concentration. Strong alignment effects are revealed by linear dichroism experiments for Fmoc-GRDS. Cryo-TEM and smallangle X-ray scattering (SAXS) reveal that both samples form fibrils with a diameter of approximately 10 nm. Both Fmoc-tetrapeptides form self-supporting hydrogels at sufficiently high concentration. Dynamic shear rheometry enabled measurements of the moduli for the Fmoc-GRDS hydrogel, however syneresis was observed for the Fmoc-RGDS hydrogel which was significantly less stable to shear. Molecular dynamics computer simulations were carried out considering parallel and antiparallel b-sheet configurations of systems containing 7 and 21 molecules of Fmoc-RGDS or Fmoc-GRDS, the results being analyzed in terms of both intermolecular structural parameters and energy contributions

Multiply Folded Graphene

The folding of paper, hide, and woven fabric has been used for millennia to achieve enhanced articulation, curvature, and visual appeal for intrinsically flat, two-dimensional materials. For graphene, an ideal two-dimensional material, folding may transform it to complex shapes with new and distinct properties. Here, we present experimental results that folded structures in graphene, termed grafold, exist, and their formations can be controlled by introducing anisotropic surface curvature during graphene synthesis or transfer processes. Using pseudopotential-density functional theory calculations, we also show that double folding modifies the electronic band structure of graphene. Furthermore, we demonstrate the intercalation of C60 into the grafolds. Intercalation or functionalization of the chemically reactive folds further expands grafold's mechanical, chemical, optical, and electronic diversity.Comment: 29 pages, 10 figures (accepted in Phys. Rev. B

¿Le parece bien a nuestros pacientes que su médico de familia interino consolide su empleo en la OPE extraordinaria actualmente en marcha?

IntroducciónLa situación laboral de los médicos de atención primaria puede influir positiva o negativamente en la satisfacción personal de éstos, e indirectamente en la relación médico-paciente. Cabe suponer que un médico de familia con inestabilidad laboral y poco motivado por parte del sistema sanitario tendrá más dificultad para prestar una atención sanitaria de calidad a sus pacientes. Pero ¿qué opinan nuestros pacientes?1-4, ¿les parece bien que su médico tenga estabilidad en su empleo? o ¿prefieren que sea interino para que no se deje llevar por la rutina? Estas cuestiones son las que se intentan aclarar en esta investigación.ObjetivoConocer la opinión de nuestros pacientes acerca de que su médico de familia (MF) interino pase a ser propietario en el proceso extraordinario de consolidación de empleo inciado en diciembre de 2001.DiseñoSe trata de un estudio observacional mediante encuesta en el que no se aplica ninguna intervención.EmplazamientoCentro de salud semiurbano de la periferia de nuestra ciudad.ParticipantesSe seleccionó aleatoriamente al salir de la consulta a 200 pacientes de 3 cupos cuyos MF ocupan plaza de interino y están inmersos en el proceso extraordinario de consolidación de empleo.Mediciones principalesSe les realizó una encuesta autocumplimentada que constaba de 5 afirmaciones para las cuales había 5 opciones de respuesta (muy de acuerdo, de acuerdo, indiferente, en desacuerdo, muy en desacuerdo). Las afirmaciones planteadas a los pacientes eran las siguientes:1.Mi MF estará más tranquilo y será más complaciente si tiene plaza en propiedad, y esto conllevará una mejora de la relación médico-paciente.2.Si mi MF tiene plaza en propiedad, tendrá más tiempo para formación continuada útil, ya que no preparará oposiciones.3.Prefiero que mi MF sea interino, pues así estudiará más.4.Si mi MF es propietario, como es más difícil que le echen de su puesto de trabajo, adquirirá mentalidad de funcionario y nos prestará una atención de peor calidad.5.Un MF debe de trabajar a gusto y estar motivado, por lo que para ello es importante que tenga plaza en propiedad.6.La encuesta fue previamente diseñada por un grupo de 4 médicos de familia siguiendo una técnida Delphi modificada, de la cual surgieron las 5 afirmaciones planteadas.ResultadosEl 72% de los pacientes cree que su MF estará más tranquilo, será más complaciente y mejorará la relación medico-paciente si consolida su plaza en la OPE extraordinaria. Un 42% de los pacientes cree que si un médico tiene plaza en propiedad mejorará en su formación continuada sobre aspectos útiles para su práctica clínica. El 78% de los pacientes opina que si su MF consolida su plaza adquirirá mentalidad de funcionario y prestará una atención de peor calidad. El 62% cree que si su médico tiene plaza en propiedad estará más motivado globalmente y trabajará más a gusto (tabla 1).Discusión y ConclusionesLa última década se ha caracterizado por la escasez de oposiciones para adquirir plaza fija como MF en el sistema nacional de salud. Esto ha llevado a la administración a poner en marcha una oferta pública de empleo (OPE) extraordinaria en diciembre del 2001. En este trabajo, nuestros pacientes nos aportan 2 mensajes principales; en primer lugar, creen que su médico va a trabajar más relajado, mejor y se formará en lo que él considere útil para su práctica clínica diaria si logra consolidar su plaza; en segundo lugar nos advierten del peligro que puede ocasionar que su médico esté tranquilo laboralmente y nos dicen que un medico propietario estudiará menos y además puede adquirir mentalidad de funcionario, con el consiguiente deterioro de la atención que ello conllevaría. En conclusión, nuestros pacientes consideran que si su MF consolida su plaza mejorará la relación médico-paciente, pero adquirirá una mentalidad funcionarial que le hará prestar una atención de inferior calidad.

Three-dimensional printed polycaprolactone-microcrystalline cellulose scaffolds

Microcrystalline cellulose (MCC) is proposed in this study as an additive in polycaprolactone (PCL) matrices to obtain three-dimensional (3D) printed scaffolds with improved mechanical and biological properties. Improving the mechanical behavior and the biological performance of polycaprolactone-based scaffolds allows to increase the potential of these structures for bone tissue engineering. Different groups of samples were evaluated in order to analyze the effect of the additive in the properties of the PCL matrix. The concentrations of MCC in the groups of samples were 0, 2, 5, and 10% (w/w). These combinations were subjected to a thermogravimetric analysis in order to evaluate the influence of the additive in the thermal properties of the composites. 3D printed scaffolds were manufactured with a commercial 3D printer based on fused deposition modelling. The operation conditions have been established in order to obtain scaffolds with a 0/90° pattern with pore sizes between 450 and 500 µm and porosity values between 50 and 60%. The mechanical properties of these structures were measured in the compression and flexural modes. The scaffolds containing 2 and 5% MCC have higher flexural and compression elastic modulus, although those containing 10% do not show this reinforcement effect. On the other hand, the proliferation of sheep bone marrow cells on the proposed scaffolds was evaluated over 8 days. The results show that the proliferation is significantly better (p < 0.05) on the group of samples containing 2% MCC. Therefore, these scaffolds (PCL:MCC 98:2) have suitable properties to be further evaluated for bone tissue engineering applications