A procedure to evaluate the resistance to biological colonization as a characteristic for product quality of ceramic roofing tiles

9 pages, 5 figures, 4 tables, 22 references. The authors acknowledge the collaboration of the company Cerámica La Escandella (Spain) in supplying the samples of ceramic roofing tiles, and the advice and support by Dr. José Enrique Frias (Servicio de Cultivos Biológicos, Instituto de Biologia Vegetal y Fotosíntesis, CSIC, Seville, Spain) who provided us with the cyanobacterial strains used in this work.Ceramic roofing tiles suffer deterioration through time due to environmental exposure. Biological colonization affects the appearance and integrity of building materials, such as roofing tiles. The resistance to biocolonization represents an important property affecting the product quality of ceramic roofing tiles. While natural colonization of roofing tiles by organisms is a progressive, heterogeneous, and slow process, laboratory assessment of this phenomenon requires a sensitive procedure that can be carried out within a reasonable period of time. Different microorganisms have been evaluated and the use of phototrophs, specifically the cyanobacterium Oscillatoria, presented several advantages such as good adherence, homogeneous growth on surfaces, and the chlorophyll-autofluorescence which can be used for a sensitive detection. Colonization by Oscillatoria on roofing tiles was assessed by measuring the autofluorescence of cells. This study proposes the use of specific cyanobacterial cells and a simple method for monitoring biofilm formation and biological colonization of roofing tiles.. This study was funded by project PET2007-0080 from the Spanish Ministry of Science and Innovation.Peer reviewe

Efecto del ZnO, ZrO2 y B2O3 en el proceso de clinkerización. Parte II. Metodología de separación de fases y distribución en las fases del clínker

This study is a continuation of previous research which established the effect of the oxides ZnO, ZrO2 and B2O3, both separately and jointly, on clinkerization processes, as well as on clinker phase composition and morphology. A knowledge of the distribution of these elements in mineral phases is requisite to understanding which phases they affect and how. The present study aimed, then, to develop a suitable methodology for the selective separation of clinker phases and to ascertain how ZnO, ZrO2 and B2O3 are distributed in these phases when added to the raw mix in proportions of up to 2%. The optimal conditions for separating clinker phases with selective solutions (KOH-sucrose and CH3OHsalicylic acid) were established. These selective treatments proved to be insufficient in and of themselves to determine the distribution of ZnO and ZrO2 in the clinker phases. Consequently, the original clinkers had to be analyzed with SEM/BSE/EDX techniques to complete the study. The findings showed that ZnO and ZrO2 were fixed primarily in the C3A and C4AF present in the clinker, while B2O3 was taken up by the silicate phases.Este trabajo es la continuación de otro anterior en el que se estableció la influencia de los óxidos ZnO, ZrO2 y B2O3, tanto de manera individualizada como conjunta, en los procesos de clinkerización, así como en la composición y morfología de las fases del clínker. Conocer cómo se distribuyen estos elementos en las fases mineralógicas, permite comprender cómo y a qué fases afectan. Por ello el objetivo de este trabajo fue obtener una metodología adecuada para la separación selectiva de las fases del clínker, y conocer cómo se distribuyen en estas fases adiciones de hasta el 2% de los óxidos de ZnO, ZrO2 y B2O3 adicionados al crudo. Se establecieron las condiciones óptimas para la separación de las fases del clínker a través de diferentes disoluciones selectivas (KOH-Sacarosa y CH3OH-Ac. salicílico). Se ha demostrado que estos tratamientos selectivos por sí solos no son adecuados para conocer la distribución del ZnO y el ZrO2 en las fases del clínker, siendo necesario completar el estudio con análisis por SEM/BSE/EDX sobre los clínkeres originales. Los resultados obtenidos muestran que el ZnO y ZrO2 se fijan mayoritariamente en las fases C3A y C4AF del clínker; por el contrario, el B2O3 se incorpora a las fases silicato

A procedure to evaluate the resistance to biological colonization as a characteristic for product quality of ceramic roofing tiles

Abstract Ceramic roofing tiles suffer deterioration through time due to environmental exposure. Biological colonization affects the appearance and integrity of building materials, such as roofing tiles. The resistance to biocolonization represents an important property affecting the product quality of ceramic roofing tiles. While natural colonization of roofing tiles by organisms is a progressive, heterogeneous, and slow process, laboratory assessment of this phenomenon requires a sensitive procedure that can be carried out within a reasonable period of time. Different microorganisms have been evaluated and the use of phototrophs, specifically the cyanobacterium Oscillatoria, presented several advantages such as good adherence, homogeneous growth on surfaces, and the chlorophyll-autofluorescence which can be used for a sensitive detection. Colonization by Oscillatoria on roofing tiles was assessed by measuring the autofluorescence of cells. This study proposes the use of specific cyanobacterial cells and a simple method for monitoring biofilm formation and biological colonization of roofing tiles

LCA applied to perennial cropping systems: a review focused on the farm stage

International audienc

Assessment of plasma chitotriosidase activity, CCL18/PARC concentration and NP-C suspicion index in the diagnosis of Niemann-Pick disease type C: A prospective observational study

Background: Niemann-Pick disease type C (NP-C) is a rare, autosomal recessive neurodegenerative disease caused by mutations in either the NPC1 or NPC2 genes. The diagnosis of NP-C remains challenging due to the non-specific, heterogeneous nature of signs/symptoms. This study assessed the utility of plasma chitotriosidase (ChT) and Chemokine (C-C motif) ligand 18 (CCL18)/pulmonary and activation-regulated chemokine (PARC) in conjunction with the NP-C suspicion index (NP-C SI) for guiding confirmatory laboratory testing in patients with suspected NP-C. Methods: In a prospective observational cohort study, incorporating a retrospective determination of NP-C SI scores, two different diagnostic approaches were applied in two separate groups of unrelated patients from 51 Spanish medical centers (n = 118 in both groups). From Jan 2010 to Apr 2012 (Period 1), patients with =2 clinical signs/symptoms of NP-C were considered ''suspected NP-C'' cases, and NPC1/NPC2 sequencing, plasma chitotriosidase (ChT), CCL18/PARC and sphingomyelinase levels were assessed. Based on findings in Period 1, plasma ChT and CCL18/PARC, and NP-C SI prediction scores were determined in a second group of patients between May 2012 and Apr 2014 (Period 2), and NPC1 and NPC2 were sequenced only in those with elevated ChT and/or elevated CCL18/PARC and/or NP-C SI =70. Filipin staining and 7-ketocholesterol (7-KC) measurements were performed in all patients with NP-C gene mutations, where possible. Results: In total across Periods 1 and 2, 10/236 (4%) patients had a confirmed diagnosis o NP-C based on gene sequencing (5/118 4.2%] in each Period): all of these patients had two causal NPC1 mutations. Single mutant NPC1 alleles were detected in 8/236 (3%) patients, overall. Positive filipin staining results comprised three classical and five variant biochemical phenotypes. No NPC2 mutations were detected. All patients with NPC1 mutations had high ChT activity, high CCL18/PARC concentrations and/or NP-C SI scores =70. Plasma 7-KC was higher than control cut-off values in all patients with two NPC1 mutations, and in the majority of patients with single mutations. Family studies identified three further NP-C patients. Conclusion: This approach may be very useful for laboratories that do not have mass spectrometry facilities and therefore, they cannot use other NP-C biomarkers for diagnosis

Ceramic wastes as raw materials in portland cement clinker fabrication: characterization and alkaline activation

12 páginas, 6 figuras, 7 tablas.[ES] La industria cementera mundial está buscando vías experimentales que permitan desarrollar cementos que precisen menor energía en su formación, degraden menos los entornos y emitan menos gases contaminantes a la atmósfera. Esta línea, en España y Europa, coincide plenamente con el concepto de sostenibilidad y alcanzar el cumplimiento del Protocolo de Kioto. El empleo de diferentes residuos y subproductos industriales como materiales alternativos en la fabricación de cemento se ha revelado como un medio muy efectivo para alcanzar, en gran parte, esa sostenibilidad. Estos materiales alternativos pueden ser incorporados en el proceso de fabricación de cemento, por la sustitución parcial de los combustibles convencionales y/o de las materias primas del crudo y por la incorporación de adiciones activas al cemento y/o clínker. En el presente trabajo se exponen los resultados preliminares obtenidos al estudiar la composición y activación alcalina de seis residuos cerámicos cocidos con vistas a su viabilidad de sustituir, parcialmente, algunas materias primas, utilizadas en la preparación de un crudo de cemento. Los resultados obtenidos han mostrado que los seis residuos tienen una composición química y mineralógica adecuada para su posible empleo como materia prima alternativa de un crudo de cemento Portland. No son ni tóxicos ni radioactivos. Como era de esperar estos residuos tienen capacidad puzolánica. A la edad de estudio (8 días) la activación alcalina de los residuos es baja. El contenido en fase amorfa y la naturaleza del activador no parecen ser factores que influyan en dicho proceso de activación. El estudio de caracterización realizado sobre las pastas activadas ha demostrado que las fases feldespáticas son las más susceptibles de disolución y reacción con las disoluciones alcalinas.[EN] The world-wide cement industry is seeking experimental avenues that will lead to cement production that is less energy-intensive, less damaging to the surrounding environment and less prolific in GHG emissions. In Spain and Europe in general, this approach is wholly consistent with the concept of sustainability and compliance with the Kyoto Protocol. The use of different kinds of industrial waste and by-products as alternative materials in cement manufacture has proved to be a very effective way of contributing to such sustainability. These alternative materials may be incorporated during cement production by partial/y replacing conventional fuel and/or the raw materials ground into the raw mix, or by including active additions to the cement and/or clinker. The present paper discusses the preliminary results obtained in a study of the composition and alkali activation of six types of fired ceramic waste with a view to their viability as partial replacements for some of the prime materials used to prepare raw mix for Portland cement. The results show that the chemical and mineralogical composition of the six materials makes them apt for such possible use. They are neither toxic nor radioactive. And as might be expected this type of waste exhibits pozzolanic activity. Alkali activation of the waste, low at the age analyzed (8 days), does not appear to be affected by the vitreous phase content or the nature of the activator. The characterization study conducted on the activated paste shows that the feldspar phases are the ones most susceptible to dissolution and reaction with the alkaline solutions.Los autores agradecen al Ministerio de Educación y Ciencia (MEC) la subvención otorgada al proyecto CTM200406619-C02-01 y 02/TECHNO dentro del cual se han realizado estas investigaciones. M. Palacios también agradece a la Consejería de Educación de la Comunidad de Madrid la concesión de una beca predoctoral y S. Martínez-Ramírez al Ministerio de Educación y Ciencia y al ERDF la financiación del Contrato Ramón y Cajal.Peer reviewe

Determinación de carbono orgánico en materias primas cerámicas en presencia de siderita, FeCO₃

Not availableLa materia orgánica es una de las impurezas presentes en las materias primas utilizadas en la fabricación de pavimentos y revestimientos cerámicos. Durante el proceso de cocción, el carbono orgánico (Corgánico) puede producir la aparición de un núcleo negro conocido como “corazón negro”, que puede causar defectos en el producto final. 
 Las materias primas cerámicas contienen Corgánico a nivel de mg·kg-1 (procedente de la materia orgánica) y carbono inorgánico (Cinorgánico) a nivel de porcentaje (procedente de siderita (FeCO3), calcita (CaCO3) y dolomita (CaMg(CO3)2), principalmente).
 La presencia de siderita puede interferir en la determinación de Corgánico puesto que su temperatura de descomposición difiere muy poco de la temperatura de determinación del Corgánico, no ocurriendo lo mismo con la calcita y la dolomita, cuyas temperaturas de descomposición son superiores. Existen diversos métodos para la determinación de Corgánico en muestras sólidas, aunque no se han encontrado estudios cuantitativos sobre dicha determinación en presencia de siderita. En este trabajo se han desarrollado dos métodos para determinar Corgánico en materias primas y composiciones cerámicas mediante análisis elemental, en presencia de siderita, que pueden ser utilizados en el control de la aparición de corazón negro en baldosas cerámicas. La metodología desarrollada presenta bajos límites de cuantificación e incertidumbres, siendo un método rápido y preciso