Study of alkaline hydrothermal activation of belite cements by thermal analysis

The effect of alkaline hydrothermal activation of class-C fly ash belite cement was studied using thermal analysis (TG/DTG) by determining the increase in the combined water during a period of hydration of 180 days. The results were compared with those obtained for a belite cement hydrothermally activated in water. The two belite cements were fabricated via the hydrothermal-calcination route of class-C fly ash in 1 M NaOH solution (FABC-2-N) or demineralised water (FABC-2-W). From the results, the effect of the alkaline hydrothermal activation of belite cement (FABC-2-N) was clearly differentiated, mainly at early ages of hydration, for which the increase in the combined water was markedly higher than that of the belite cement that was hydrothermally activated in water. Important direct quantitative correlations were obtained among physicochemical parameters, such as the combined water, the BET surface area, the volume of nano-pores, and macro structural engineering properties such as the compressive mechanical strength

Should Forest Transition Theory include effects on forest fires? The case of Spain in the second half of the twentieth century

This paper analyses the increase in forest surface covered by trees in Spain in the second half of the twentieth century in the light of Forest Transition Theory and explores the existence of a statistical relationship between this process and forest fires. The study describes the afforestation policy based on new forest plantations developed by Franco''s Dictatorship in the period 1940–1988, linking it to the forest fires that occurred in the period 1968–2002, in order to determine, at a provincial level, the extent to which the afforestation activity affected the number of hectares burnt. The evidence shows a significant positive relationship between forest fires and the afforested hectares, especially 30–35 years after plantations. The effect increases when the model is implemented exclusively for the Cantabrian and Atlantic north-west provinces, especially affected by afforestation programmes. Our findings reinforce the need to complement certain models of Forest Transition based on tree plantations, taking into account the possible relationship that they have with fires, particularly in environmental contexts prone to fires

Formulación de cementos bioactivos mediante la adición de sales de Hidroxiapatita-Estroncio

Se han formulado cementos óseos acrílicos inyectables para su uso en vertebroplastia (VP) y se les ha proporcionado bioactividad mediante la incorporación de sales de hidroxiapatita estroncio (HASr). El objetivo es combinar la fijación inmediata que proporciona el cemento acrílico, con la fijación a largo plazo que proporciona la HASr. Además, la presencia de Sr en la carga proporciona radiopacidad, con lo cual se evita la adición de agentes radiopacos adicionales. Así, se estudió el efecto de la incorporación de la HASr en las propiedades del cemento óseo. La adición se realizó en la fase sólida de 2 modos diferentes: en polvo, tal como se obtiene tras la síntesis y después de un sencillo tratamiento superficial con monómero. Los resultados muestran que el tratamiento mejora la mojabilidad de las partículas, lo que mejora la inyección de estos cementos y proporciona propiedades mecánicas superiores, sin perjudicar al contenido de monómero residual. La formulación de cemento idónea para VP sería la que contiene un 20% de HASr tratada, ya que presenta una inyectabilidad mejorada, elevada radiopacidad, la mayor bioactividad y además, la mejora de propiedades mecánicas es significativa

Formulación de cementos bioactivos mediante la adición de sales de hidroxiapatita-estroncio

Se han formulado cementos óseos acrílicos inyectables para su uso en vertebroplastia (VP) y se les ha proporcionado bioactividad mediante la incorporación de sales de hidroxiapatita estroncio (HASr). El objetivo es combinar la fijación inmediata que proporciona el cemento acrílico, con la fijación a largo plazo que proporciona la HASr. Además, la presencia de Sr en la carga proporciona radiopacidad, con lo cual se evita la adición de agentes radiopacos adicionales. Así, se estudió el efecto de la incorporación de la HASr en las propiedades del cemento óseo. La adición se realizó en la fase sólida de 2 modos diferentes: en polvo, tal como se obtiene tras la síntesis y después de un sencillo tratamiento superficial con monómero. Los resultados muestran que el tratamiento mejora la mojabilidad de las partículas, lo que mejora el mezclado de estos cementos y proporciona propiedades mecánicas superiores. La formulación de cemento idónea para VP sería la que contiene un 20% de HASr tratada, ya que presenta una elevada radiopacidad, la mayor bioactividad y además, la mejora de propiedades mecánicas es significativa.Bioactive and injectable bone cements designed to perform vertebroplasty (VP) have been prepared by adding strontium hydroxyapatite (SrHA) to a formulation based on methylmethacrylate. Thus, the cement combines the immediate support given by the setting of the acrylic matrix, with the long term integration due to the incorporation of the SrHA. Moreover, the presence of Strontium makes this filler highly radiopaque, which avoids the undesirable and extended practice of the addition of more radiopaque substances by the surgeon. For that purpose, the effect of the addition of SrHA particles, incorporated ‘as synthetised’ and after a surface treatment with the monomer, was studied on various properties of the cement. Results showed that the surface treatment improved the wettability of the SrHA particles, and, as a consequence, the mixing and the mechanical properties. The best formulation to perform VP is 20%-treated SrHA containing formulation, which shows enhanced mechanical properties compared with control formulations, along with high radiopacity and the higher bioactivity

Relationships between adolescent physical self-concept and physical activity

El objetivo de este estudio es someter a prueba dos modelos contrapuestos sobre las relaciones entre las autopercepciones físicas y la actividad físico-deportiva en la adolescencia: mientras que un modelo postula la influencia de la actividad física sobre el autoconcepto físico, el modelo alternativo propone al autoconcepto físico como factor influyente en la actividad físicodeportiva. Participan en la investigación 704 estudiantes, 394 (55.96 %) hombres y 310 (44.04 %) mujeres entre 11 y 19 años (M = 14.91; D.T. = 2.13), residentes en dos Comunidades Autónomas (Cantabria y País Vasco) de España. Los resultados indican que las influencias entre el autoconcepto físico y la actividad físico-deportiva se producen de forma bidireccional si bien ajusta mejor el modelo que propone al autoconcepto físico como factor influyente. Se comprueban diferencias entre hombres y mujeres en el modelo. Por otro lado, la autopercepción de atractivo físico mantiene una relación negativa con la actividad físico-deportivaThe aim of this study is to test two opposing models of the relationship between physical self-perceptions and physical activity during adolescence: one which postulates that physical activity influences physical self-concept, and another one which proposes that physical self-concept influences physical activity. Participants were 704 students aged between 11 and 19 (M = 14.91; SD = 2.13) from two different Autonomous Regions in Spain (Cantabria and the Basque Country). 394 (55.96%) were male and 310 (44.04%) were female. The results indicate that the influences between physical self-concept and physical activity are bidirectional in nature, although the model that proposes physical selfconcept as an influencing factor was found to have a better fitness. Differences were found in the model between male and female students. Furthermore, selfperception of physical attractiveness was found to be negatively related to physical activityEste artículo lo firman componentes del Grupo Consolidado de Investigación del Sistema Universitario Vasco IT701-13 y forman parte de los resultados del proyecto EDU2009-10102 (subprograma EDUC) subvencionado por el MICINN. La investigación se ha realizado con la colaboración del Programa para la Contratación de Doctores Recientes de la Universidad del País Vasco (UPV/EHU

Continuity, change, and geographical differences in Spain's firewood consumption: A new estimation (1860-2010)

Although firewood was the main energy source until recently in most parts of the world, our understanding of its consumption levels is still quite limited, even in regard to recent periods. The powerful impact of fossil energy carriers and their major effects on global ecology, economy and society have led us to underestimate the role firewood has continued to play during the energy transition. This article offers a new reconstruction of long-ter m firewood consumption in Spain, taking into consideration variables related to supply and demand, which are then used to reconstruct the production, appropriation and energy uses of firewood biomass. This new series distinguishes also between the origins (forest or crop firewood), and between different regional behaviors. The main findings indicate that total and per-inhabitant consumption has been greater than traditionally assumed; that there was major regional divergence, with consumption varying significantly from one area to another; that the decline in firewood consumption was gradual and later than previously thought; and that it increased or declined over time in a non-linear fashion. Moreover, the traditionally neglected estimation of the role of woody crops was found to be very significant in this process, as it represented between 20% and 70% of total consumption for the whole data series

Structural and functional interaction between polyamine related molecules and biological membranes

La comunicación describe el conocimiento actual sobre las interacciones de biomoléculas relacionadas con el metabolismo de poliaminas con las estructuras y funciones de las membranas biológicasChanges induced by PA on nucleic acid (NA) conformation and synthesis is proven to be a major reason for PA essentiality (1-3). However, PA interactions with other polyanions, for instance polyanionic membrane lipid bilayers and glyosaminoglycans have received less attention (3-4). The functional importance of these interactions still is an obscure but interesting area of cell and molecular biology, especially in mammalian cells for which specific PA transport systems are not fully characterized (5). In mammals, activity and turnover of the polyamine (PA) synthesis key enzyme is controlled by a set of proteins: Antizymes (OAZ1-3) and antizyme inhibitors (AZIN1 and 2). It is demonstrated that AOZ modulate polyamine uptake (6), and that PA transport to mitochondria is linked to the respiratory chain state and modulates mitochondrial permeability transition (7). Antizyme expression variants have been located in mitochondria, being proposed as a proapoptotic factor (7-8). AZIN 2 is only expressed in a reduced set of tissues that includes mast cells, where it is associated to mast cell granules membrane (9). This fact, together to the abnormalities observed in bone marrow derived mast cell granules when they are differentiated under restricted PA synthesis conditions (10 and unpublished results), point out to important roles of PA and their related proteins in structure and function of mast cell granules. We will also present novel biophysical results on tripartite interactions of PA that remark the interest of the characterization of PA interactions with lipid bilayers for biomedicine and biotechnology. Thus, the information reported in this paper integrates previously reported information with our still unpublished results, all indicating that PA and their related proteins also are important factors for structure and dynamics of biological membranes and their associated functions essential in human physiology; for instance, solute interchange with the environment (uptake and secretion), oxidative metabolism and apoptosis. The importance of these involved processes for human homeostasis claim for further research efforts. 1. Ruiz-Chica J, Medina MA, Sánchez-Jiménez F and Ramírez FJ (2001) Fourier Transform Raman study of the structural specificities on the interaction between DNA and biogenic polyamines. Biophysical J. 80:443-454. 2. Lightfoot HL, Hall J (2014) Endogenous polyamine function--the RNA perspective. Nucleic Acids Res. 42:11275-11290. 3. Igarashi K, Kashiwagi K (2010) Modulation of cellular function by polyamines. Int J Biochem Cell Biol. 42:39-51. 4. Finger S, Schwieger C, Arouri A, Kerth A, Blume A (2014) Interaction of linear polyamines with negatively charged phospholipids: the effect of polyamine charge distance. Biol Chem. 395:769-778. 5. Poulin R, Casero RA, Soulet D. (2012) Recent advances in the molecular biology of metazoan polyamine transport. Amino Acids. 42:711-723. 6. Kahana C (2009) Regulation of cellular polyamine levels and cellular proliferation by antizyme and antizyme inhibitor. Essays Biochem. 4:47-61. 7. Agostinelli E, Marques MP, Calheiros R, Gil FP, Tempera G, Viceconte N, Battaglia V, Grancara S, Toninello A (2010) Polyamines: fundamental characters in chemistry and biology. Amino Acids 38:393-403. 8. Liu GY, Liao YF, Hsu PC, Chang WH, Hsieh MC, Lin CY, Hour TC, Kao MC, Tsay GJ, Hung HC (2006) Antizyme, a natural ornithine decarboxylase inhibitor, induces apoptosis of haematopoietic cells through mitochondrial membrane depolarization and caspases' cascade. Apoptosis 11:1773-1788. 9. Kanerva K, Lappalainen J, Mäkitie LT, Virolainen S, Kovanen PT, Andersson LC (2009). Expression of antizyme inhibitor 2 in mast cells and role of polyamines as selective regulators of serotonin secretion. PLoS One 31:e6858. 10. García-Faroldi G, Rodríguez CE, Urdiales JL, Pérez-Pomares JM, Dávila JC, Pejler G, Sánchez-Jiménez F, Fajardo I (2010) Polyamines are present in mast cell secretory granules and are important for granule homeostasis. PLoS One 30:e15071.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Structure and properties of the outer membranes of Brucella abortus and Brucella melitensis

The brucellae are Gram-negative bacteria characteristically able to multiply facultatively within phagocytic cells and which cause a zoonosis of world-wide importance. This article reviews the structure and topology of the main components (lipopolysaccharide, native hapten polysaccharide, free lipids and proteins) of the outer membranes of Brucella abortus and B. melitensis, as well as some distinctive properties (permeability and interactions with cationic peptides) of these membranes. On these data, an outer membrane model is proposed in which, as compared to other Gram-negatives, there is a stronger hydrophobic anchorage for the lipopolysaccharide, free lipids, porin proteins and lipoproteins, and a reduced surface density of anionic groups, which could be partially or totally neutralized by ornithine lipids. This model accounts for the permeability of Brucella to hydrophobic permeants and for its resistance to the bactericidal oxygen-independent systems of phagocytes