Search results for " mineral"
showing 10 items of 541 documents
A Study on Acidification and Intercalation of Illite Clay Minerals and their Potential Use as a Filler in SPEEK Composite Membranes
2018
The acidification and intercalation of illite containing clays were studied for potential use as fillers for sulphonated poly (ether ether ketone) (SPEEK) composite membrane preparation and future proton exchange membrane fuel cells application. The acidification and dimethyl sulfoxide (DMSO) intercalation of illite clays have been studied by powder X-ray diffractometry, X-ray fluorescence spectrometry, and thermogravimetric analysis. SPEEK composite membranes were made with 1, 3 and 5% purified, acidified, DMSO intercalated clay fillers. SPEEK/clay composite membranes were characterized by proton conductivity, water uptake, and mechanical strength.
Covalently modified nanoclays: synthesis, properties and applications
2020
Abstract Clay minerals are phyllosilicates of nanoscale dimensions. According to their ability to entrap and release organic moieties, they have found applications in several fields, such as drug carrier and delivery, support for catalyst, environmental remediation and filler for polymeric matrices. The possibility to modify, by covalent linkage, their surfaces gives the possibility to form new nanomaterials with improved properties respect to the pristine clay minerals. In this chapter, the modifications of the siloxane surfaces of the most representative clay minerals, namely montmorillonite, sepiolites, laponite and halloysite were reviewed and discussed.
Nuevos desarrollos de la espectroscopia para el análisis mineral de alimentos
2017
El trabajo recopilado en la siguiente Tesis Doctoral está basado en el desarrollo de nuevas metodologías para la determinación de elementos minerales en distintos alimentos y dietas, siguiendo los principios de la “Química Verde”: rapidez, bajo coste, simplicidad y respeto por el medio ambiente. Esta Tesis se ha realizado acogiéndose a la modalidad “compendio de publicaciones”, contemplada en el Reglamento de la Universidad de Valencia de 28/16/2016 (ACGUV 172/2016) y se ha dividido en dos secciones: la sección I, que incluye un resumen global de la temática, resumen de los principales resultados obtenidos, así como las conclusiones finales. A continuación, en la sección II se incluyen los …
Estrategias biotecnológicas para reducir el contenido en fitatos en productos fermentados de origen vegetal mediante fitasas de bifidobacterias
2015
Los alimentos integrales de origen vegetal, concretamente, los cereales de grano entero y leguminosas se caracterizan por ser una fuente excelente de fibra dietética y poseer un elevado contenido en compuestos fitoquímicos. Además de proporcionar macronutrientes, como carbohidratos complejos y proteínas, también destacan por su contenido en micronutrientes como son las vitaminas y minerales. Sin embargo, su ingesta conlleva a la vez un aporte en sustancias antinutritivas, como los fitatos, con gran afinidad por minerales, proteínas y elementos traza, que pueden comprometer su absorción por formación de quelatos estables en el tracto digestivo. Una hidrólisis o defosforilación parcial de los…
Pietre figurate. Forme del fantastico e mondo minerale
2004
Le pietre figurate sono particolari sezioni di minerali che mostrano meravigliosi disegni, capaci di evocare nell’immaginazione dell’uomo organismi vegetali e animali, ma anche paesaggi o motivi geometrici. Dall’antichità al Novecento le pietre figurate hanno cambiato più volte statuto ontologico. Esse sono state considerate oggetti da collezione, emblemi di prodigiosità o curiosità; opere d’arte attribuite alla natura o ad un artefice supremo, in concorrenza con le opere degli artisti; sono state, infine, contemplate come scrigni e custodi di un segreto rivelato nella “scrittura lapidea”, insieme, sotterranea e palese. Il volume è rivolto allo studio delle forme dell’immaginario minerale, …
Biogenic Fenton process - A possible mechanism for the mineralization of organic carbon in fresh waters.
2020
To explore the mechanisms that mineralize poorly bioavailable natural organic carbon (OC), we measured the mineralization of OC in two lake waters over long-term experiments (up to 623 days) at different pH and iron (Fe) levels. Both the microbial and photochemical mineralization of OC was higher at pH acidified to 4 than at the ambient pH 5 or an elevated pH 6. During 244 days, microbes mineralized up to 60% of OC in the 10-mu m filtrates of lake water and more than 27% in the 1-mu m filtrates indicating that large-sized microbes/grazers enhance the mineralization of OC. A reactivity continuum model indicated that the acidification stimulated the microbial mineralization of OC especially i…
Ultrasound measurements in bone using an array transducer
2014
Perception of mineral character in Sauvignon blanc wine: inter-individual differences
2014
Revue non indexée dans le JCR.; Of the descriptors employed to characterize wine organoleptically, minerality is arguably one of the most enigmatic. The aim of the work described in this article was to delineate the nature of perceived minerality in Sauvignon wine, specifically its sensorial reality for experienced wine professionals from France and New Zealand. Participants evaluated 16 Sauvignon blanc wines (8 French; 8 New Zealand) under three conditions, ortho-nasal olfaction, palate only (Nose-clip condition), and by full tasting (global perception). Data from the global condition only are reported here. Key results include: i) that although there were quantitative differences in perce…
Differential effects of sex hormones on peri- and endocortical bone surfaces in pubertal girls.
2005
Context: The role of sex steroids in bone growth in pubertal girls is not yet clear. Bone biomarkers are indicators of bone metabolic activity, but their value in predicting bone quality has not been studied in growing girls. Objective: This study examines the association of sex hormones and bone markers with bone geometry and density in pubertal girls. Design: The study was designed as a 2-yr longitudinal study in pubertal girls. Measurements were performed at baseline and at 1and 2-yr follow-ups. Setting: The study was conducted in a university laboratory. Participants: A total of 258 10- to 13-yr-old healthy girls at the baseline participated. Methods:Peripheralquantitativecomputedtomogr…
Impact of estrogens on atherosclerosis and bone in the apolipoprotein E-deficient mouse model.
2014
Objective The common inflammatory pathophysiology has nourished the hypothesis of a relationship between osteoporosis and cardiovascular disease. Estrogens are key agents in the modulation of both processes. We investigated whether induction of atherosclerosis affects bone and whether estrogens modulate both processes. Methods Female apolipoprotein E-deficient mice (a well-established model of atherogenesis) were ovariectomized or falsely operated and fed either standard diet or high-fat diet (HFD). Six animals were included in each of the four groups. To clarify mechanisms, we treated preosteoblastic MC3T3-E1 cells with mouse serum. Results Physiological levels of estrogens in falsely oper…