Determinación de sulfuros de hierro en pizarras para cubiertas del noroeste de España

The most important production of roofing slates in the world is quarried from the Ordovician formations of the Truchas Syncline, which have the largest amount of working quarries. Roofing slates, sometimes, have crystallized iron sulphides such as pyrite, pyrrhotite and other minerals. These iron sulphides oxidise and stain the tiles when are exposed to atmospheric conditions, so much oxidized how much more inclined is the roof. Galician quarrymen distinguish between harmless pyrite (i.e., resistant cubes of pyrite) and damaging pyrite (i.e., other alterable metallic minerals such as pyrrhotite, chalcopyrite, marcasite and arsenopyirite). An improved identification method is proposed using both methods (a) chemical element ratios of samples under electron microprobes and (b) quantitative determination of the iron sulphides in the slate measuring the oxidized areas by digital camera. The analysed Fe/S ratios, in an XY plot, of seventy metallic samples, define three separated zones: pyrite, pyrrhotite and iron oxi-hydroxides. Quantitative determination of iron sulphides in the slate tile were performed by sinking the tile horizontally for six hours in oxygen peroxide (3% diluted) and capturing the oxidation areas with a magnetic camera and analysing the bitmap images with Sigma-Scan 5 software. The proposed method is faster than the Spanish UNE norm (UNE-EN- 12326-2 Sept.2000), which requires thermal strike cycles for a month. The necessary use of heavy analytical equipment such as electron microprobes can be facilitated by installing it in the Slate Technological Centre of Sobradelo de Valdeorras (Orense) or by using a simple optical stereoscopic zoom microscope to classify the iron minerals.Las formaciones ordovícicas del Sinclinal de Duchas concentran la mayor producción mundial de pizarra para cubiertas y el mayor número de canteras en producción. Las pizarras para cubiertas muchas veces contienen sulfuros de hierro cristalizados en forma de pirita, pirrotina y oíros minerales. Bajo condiciones atmosféricas, este tipo de sulfuros se oxida en las superficies y mancha las placas colocadas, tanto más cuanto más inclinado sea el tejado. Los productores de pizarra distinguen bien entre piritas inofensivas (es decir, cubos de pirita resistentes) y piritas oxidables (es decir, otros minerales metálicos rápidamente oxidables como pirrotina, calcopirita, marcasita y arsenopirita). Se propone una combinación de dos métodos: (a) una rutina de identificación más objetiva utilizando proporciones de elementos analizados por microsonda electrónica y (b) una determinación cuantitativa de áreas de sulfuros oxidados en planos de exfoliación (001) de pizarra mediante registro fotográfico digital. Las relaciones obtenidas Fe/S de setenta muestras metálicas se representan en un gráfico XY y se definen bien tres zonas diferentes: pirita, pirrotina y oxi-hidróxidos de hierro. La determinación cuantitativa de sulfuros de hierro en la placa de pizarra fue llevada a cabo sumergiéndola seis horas horizontalmente en agua oxigenada y después registrando las oxidaciones con una cámara fotográfica digital y analizando los resultados con programa comercial de análisis de imagen (SigmaScan v.5). El método propuesto es mejor y más rápido que la norma Española UNE vigente (UNE-EN-12326-2), que supone varios ciclos de choques térmicos durante un mes. El inconveniente del uso obligado de una microsonda electrónica podría paliarse instalando una en el Centro Tecnológico de la Pizarra de Sobradelo de Valdeorras (Orense) o utilizando una lupa binocular moderna para reconocer los minerales de hierro

Component-Resolved in Vitro Diagnosis in Peach-Allergic Patients

BACKGROUND: The in vitro diagnosis of pollen-related food allergy presents low specifi city and reproducibility with many conventional extracts. This can be improved using natural purifi ed allergens, recombinant purifi ed allergens, or both. OBJECTIVE: We compared specifi c immunoglobulin (Ig) E determination (sIgE), the basophil activation test (BAT), the histamine release test (HRT), and the cellular allergen stimulation test (CAST) using natural and recombinant allergens in the diagnosis of peach allergy. METHODS: Thirty-two peach allergic patients were studied. Skin prick tests were performed with commercial peach and extract with Mal d 1, nPru p 3, and profi lin (nPho d 2). sIgE, BAT, CAST, and HRT were determined using rPru p 3, rMal d 3, rBet v 1, rMal d 1, and rMal d 4. RESULTS: Agreement between the techniques was good with all the allergens, except HRT with rMal d 1 and rMal d 4. With rPru p 3, sIgE, CAST, BAT, and HRT showed sensitivity values of 88%, 81%, 72%, and 69% and specifi city values of 100%, 93%, 97%, and 83%, respectively. In patients with systemic symptoms or contact urticaria, the values were 100%, 85%, 81%, and 81%. In patients with oral allergy syndrome, sensitivity to profi lins or homologues of Bet v 1 was detected in 100% of the cases by all the techniques, except by HRT with rMal d 1, which detected 66% of the cases. CONCLUSIONS: The use of single allergens in the in vitro diagnosis of peach allergy by specifi c IgE determination, BAT, and CAST offers high specifi city and sensitivity, with better results than the HRT

The granites of Galicia used as industrial rock

[Resumen] Se han estudiado todos los tipos de rocas graníticas de la Comunidad Autónoma de Galicia para su utilización como roca industrial: áridos y piedra natural. El mercado de los áridos y la industria de la Piedra Natural son dos subsectores mineros de primer orden, tanto en Galicia como en el resto de España, con producciones globales en granitoides de 10 Mt (millones de toneladas) y un valor anual cercano a los 31.000 Mpts (millones de pesetas) para Galicia. Los tipos litológicos beneficiados son: granitoides inhomogéneos, granitos de dos micas, granitos biot1ticos y ortogneises, cuyas diferencias petrológicas, texturales y mineralógicas van a condicionar su nivel de calidad en uno y otro mercado.[Abstract] We have studied aH the types of granitic rocks of the region of Galicia, for their use as an industrial rock in aggregates and natural stone. The aggregate market and the natural stone industry are very important mining subsection, as much in Galicia as in the rest of Spain, with general granite productions of 10 Mt (millions of tonnes) and 31.000 Mpts (miHions of pesetas) as the annual value in Galicia. The types of mining rocks are: inhomogeneous granite, two mica granite, biotite granite and granite gneiss, whose petrological, textural and mineralogical differences determine their quality level in both uses

Component-resolved diagnosis of pollen allergy based on skin testing with profilin, polcalcin and lipid transfer protein pan-allergens

BACKGROUND Allergy diagnosis needs to be improved in patients suffering from pollen polysensitization due to the existence of possible confounding factors in this type of patients. OBJECTIVE To evaluate new diagnostic strategies by comparing skin responses to pan-allergens and conventional allergenic extracts with specific IgE (sIgE) to purified allergen molecules. METHODS One thousand three hundred and twenty-nine pollen-allergic patients were diagnosed by a combination of an in vitro method with a panel of 13 purified allergens, including major allergens and pan-allergens, using a high-capacity screening technology (ADVIA-Centaur®) and skin prick test (SPT) to pan-allergens and conventional extracts. RESULTS There was a high concordance (κ index) between in vitro (sIgE to major allergens) and in vivo (SPT to conventional extracts) methods in patients who were not sensitized to pan-allergens, but SPT with conventional extracts failed to diagnose patients with sensitization to pan-allergens. In patients who were simultaneously sensitized to polcalcins and profilins, there was a duplication both in the number of sensitizations to major allergens and in the years of disease evolution. There was a statistical association between sensitization to profilins and/or lipid transfer proteins and food allergy (P<0.0001). CONCLUSION The novel diagnostic strategy has proven to be a valuable tool in daily clinical practice. Introduction of routine SPT to pan-allergens is a simple and feasible way of improving diagnostic efficacy. Patients sensitized to pan-allergens should be tested by an adequate panel of allergenic molecules in order to identify the allergens that are responsible for the allergic disease

Metodología de investigación de los yacimientos de pizarras para cubiertas

[Resumen] Se exponen .las bases metodológicas autores aplican a la investigación y de yacimientos de pizarras para cubiertas, tanto de su propia experiencia como de bibliografía disponible sobre el tema. Los factores que controlan la calidad de los yacimientos de dicha materia prima son de tres tipos: Litoestratigráficos, estructurales y metamórficos. Ellos se reflejan en una serie de parámetros que son los que habitua1ment e s e evalúan en e1 campo. La investigación utiliza técnicas geológicas básicas, adaptadas a las peculiaridades de la pizarra. Aquélla se lleva a cabo en tres fases. De cada una de las fases se presentan ejemplos. Se apuntan también algunas nuevas técnicas de investigación tomadas de la bibliografía, que podrían ser de aplicación en este campo.[Résumé] Il s'exposent les bases méthodologiques que 1es auteur s app1i quen t á 1I investigation et évaluation de gisements des ardoises pour couvertures, prisses autant de sa propre expérience que de la maigre bibliographie disponible sur le sujeto Les facteurs que controlent la qualité des gisements de la materie prime sont trois types: Litoestratiphiques, estructurales et metamórphiques. lIs se réfléchent sur une serp€ de parámetres que sont ceux que normalement s'evaluent sur le champ. L' investigation utilise les téc niques básiques, adaptées aux peculiarités de Celle-lá se mene á bien en trois phases. une des phases on presenten des exemples. On remarque aussi quelques nouvelles técniques 'investigation cherchées sur la bibliographie, qu'il pouvaient etre d'aplication sur ce champ

PPARγ-coactivator-1α gene transfer reduces neuronal loss and amyloid-β generation by reducing β-secretase in an Alzheimer’s disease model

Current therapies for Alzheimer’s disease (AD) are symptomatic and do not target the underlying Aβ pathology and other important hallmarks including neuronal loss. PPARγ-coactivator-1α (PGC-1α) is a cofactor for transcription factors including the peroxisome proliferator-activated receptor-γ (PPARγ), and it is involved in the regulation of metabolic genes, oxidative phosphorylation, and mitochondrial biogenesis. We previously reported that PGC-1α also regulates the transcription of β-APP cleaving enzyme (BACE1), the main enzyme involved in Aβ generation, and its expression is decreased in AD patients. We aimed to explore the potential therapeutic effect of PGC-1α by generating a lentiviral vector to express human PGC-1α and target it by stereotaxic delivery to hippocampus and cortex of APP23 transgenic mice at the preclinical stage of the disease. Four months after injection, APP23 mice treated with hPGC-1α showed improved spatial and recognition memory concomitant with a significant reduction in Aβ deposition, associated with a decrease in BACE1 expression. hPGC-1α overexpression attenuated the levels of proinflammatory cytokines and microglial activation. This effect was accompanied by a marked preservation of pyramidal neurons in the CA3 area and increased expression of neurotrophic factors. The neuroprotective effects were secondary to a reduction in Aβ pathology and neuroinflammation, because wild-type mice receiving the same treatment were unaffected. These results suggest that the selective induction of PGC-1α gene in specific areas of the brain is effective in targeting AD-related neurodegeneration and holds potential as therapeutic intervention for this disease

PPAR gamma-coactivator-1 alpha gene transfer reduces neuronal loss and amyloid-beta generation by reducing beta-secretase in an Alzheimer's disease model

Current therapies for Alzheimer’s disease (AD) are symptomatic and do not target the underlying Aβ pathology and other important hallmarks including neuronal loss. PPARγ-coactivator-1α (PGC-1α) is a cofactor for transcription factors including the peroxisome proliferator-activated receptor-γ (PPARγ), and it is involved in the regulation of metabolic genes, oxidative phosphorylation, and mitochondrial biogenesis. We previously reported that PGC-1α also regulates the transcription of β-APP cleaving enzyme (BACE1), the main enzyme involved in Aβ generation, and its expression is decreased in AD patients. We aimed to explore the potential therapeutic effect of PGC-1α by generating a lentiviral vector to express human PGC-1α and target it by stereotaxic delivery to hippocampus and cortex of APP23 transgenic mice at the preclinical stage of the disease. Four months after injection, APP23 mice treated with hPGC-1α showed improved spatial and recognition memory concomitant with a significant reduction in Aβ deposition, associated with a decrease in BACE1 expression. hPGC-1α overexpression attenuated the levels of proinflammatory cytokines and microglial activation. This effect was accompanied by a marked preservation of pyramidal neurons in the CA3 area and increased expression of neurotrophic factors. The neuroprotective effects were secondary to a reduction in Aβ pathology and neuroinflammation, because wild-type mice receiving the same treatment were unaffected. These results suggest that the selective induction of PGC-1α gene in specific areas of the brain is effective in targeting AD-related neurodegeneration and holds potential as therapeutic intervention for this disease

Cathodoluminescence Characterization of Dilute Nitride GaNSbAs Alloys

The effects of ex situ annealing in N ambient and in situ annealing in As ambient on GaNSbAs/GaAs structures grown by molecular beam epitaxy were investigated by low temperature cross-sectional cathodoluminescence (CL). The amount and distribution of Sb was measured by energy dispersive spectroscopy (EDS). The cross-sectional CL analysis of all samples reveals a shift of the near band edge (NBE) emission along the growth axis, presumably associated with a non-uniform incorporation of Sb during the growth process, in agreement with the Sb distribution measured by EDS in the as-grown sample. The NBE emission in the annealed samples presents a redshift with respect to the as-grown sample. This effect might be explained by a redistribution/activation of N in the GaNSbAs lattice since the Sb distribution measured by EDS does not reveal significant changes, within the error margin, with respect to the as-grown sample. The in situ annealed in the As overpressure sample shows the best properties for solar cells applications, i.e., a NBE peak position close to 1.0 eV and the lowest full width at half maximum of this emission.Spanish Government (MINECO Project ENE2014- 56069-C4-4-R) and Junta de Castilla y Leo´n (VA293U13 and VA081U16 Projects). The Ministry of Economy and Competitiveness MINECO supports this work through Projects TEC2014-54260- C3-1-P, TEC2014-54260-C3-2-P, TEC2014-54260- C3-3-P, PCIN-2015-181-C02-01 and PCIN-2015- 181-C02-02