Browsing by Keyword "Aging"
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Item Aging of photocatalytic coatings under a water flow: Long run performance and TiO 2 nanoparticles release(2012-07-23) Olabarrieta, Josune; Zorita, Saioa; Peña, Iratxe; Rioja, Nerea; Monzón, Oihane; Benguria, Pablo; Scifo, Lorette; ADAPTACIÓN AL CAMBIO CLIMÁTICO; Mercado; MATERIALES PARA CONDICIONES EXTREMASAlthough photocatalytic coatings may experience severe wearing in most of their application, little work has been done to investigate their aging in a comprehensive way. In this article, we present an original experimental protocol to simulate an accelerated aging of photocatalytic coatings under a water flow, and test it on two materials: a well-known commercial product, Pilkington Activ™, and an experimental coating. The influence of intrinsic properties of the coatings (chemical nature, thickness) as well as environmental parameters (water matrix, UV-light) is investigated while the consequences of aging are evaluated under three different endpoints, related either to the long run performance of photocatalytic coatings or their environmental impact: (i) loss of the photocatalytic activity, (ii) degradation of mechanical properties, and (iii) release of TiO 2 nanoparticles. It is observed that both photocatalytic coatings experienced a deactivation of their active sites upon prolonged immersion. The extent of deactivation varies depending on the coating, being around 20% for experimental coatings and 65% for Pilkington Activ™ but shows little dependency on water matrix or illumination. An alteration of mechanical properties is seen on experimental coatings, which was accompanied by TiO 2 emissions as high as 150.5μgL -1. Although no reduction in film hardness or adhesion could be evidenced for Pilkington Activ™, TiO 2 concentrations up to 30.8μgL -1 was detected in the aging water showing that some release of TiO 2 nanoparticles also took place on this material. Interestingly, a common mechanism of release, triggered by an interaction between TiO 2, NaCl and UVA could be identified. Most severe damages were observed in presence of sodium chloride. These results suggest that the use of photocatalytic coatings with surface-bound nanoparticles in environmental applications may entail new entries of nanomaterials into the aqueous medium. They also prove that aging assays are an effective way of assessing the emissions.Item Aging studies of composite alumina carbon molecular sieve membranes(2012) Tanco, M. A.Llosa; Tanaka, D. A.Pacheco; Rodrigues, S. C.; Mendes, A. M.; TECNOLOGÍA DE MEMBRANAS E INTENSIFICACIÓN DE PROCESOSItem Evaluation of photocatalytic nanoparticle release to the aquatic environment(TANGER Ltd., 2010) Zorita, Saioa; Olabarrieta, Josune; Monzón, Oihane; Rioja, Nerea; Benguria, Pablo; Scifo, Lorette; ADAPTACIÓN AL CAMBIO CLIMÁTICO; MATERIALES PARA CONDICIONES EXTREMASNanotechnology creates possibilities to produce new products with novel functionalities and improved characteristics. Therefore the incorporation of engineered nanoparticles (ENP) in commercial products is progressively increasing and so is the potential for release of these novel materials into the environment. In fact, the occurrence and release of titanium nanomaterials in a wastewater treatment plant has already been proven. This implies that nanomaterials will reach the aquatic environment and that they could represent a risk to aquatic organisms and humans. We have studied the discharge of nano-TiO2 (nTiO2) to water for two case studies related to photocatalytic nanomaterials: A- The release of nTiO2 from two photocatalytic coatings under accelerated aging under a water flow and B- The release of nTiO2 though a filtration pilot plant from tap water containing 2 mg/L nanoparticles. Case A. The influence of environmental parameters (water matrix, UV-light) was investigated while the consequences of aging were evaluated under different endpoints, among them, the release of TiO2 nanoparticles. Despite that TiO2 emissions were observed for both coatings, only one of them presented mechanical damages. TiO2 concentrations up to 150.5 μg/L were detected in the aging water. Case B. Preliminary experiments were conducted at laboratory scale to determine optimum polymeric material as well as pore size. Among the common commercial materials PVDF showed the best performance. Two different industrial hollow fiber cartridges were tested with a pore size of 0.45 μm (microfiltration) and 0.03 μm (ultrafiltration). TiO2 was detected at an average concentration of 51 μg/L in the filtered water.Item Evaluation of photocatalytic nanoparticle release to the aquatic environment(TANGER Ltd., 2012) Zorita, Saioa; Olabarrieta, Josune; Monzon, Oihane; Rioja, Nerea; Benguria, Pablo; Scifo, Lorette; ADAPTACIÓN AL CAMBIO CLIMÁTICO; MATERIALES PARA CONDICIONES EXTREMASNanotechnology creates possibilities to produce new products with novel functionalities and improved characteristics. Therefore the incorporation of engineered nanoparticles (ENP) in commercial products is progressively increasing and so is the potential for release of these novel materials into the environment. In fact, the occurrence and release of titanium nanomaterials in a wastewater treatment plant has already been proven. This implies that nanomaterials will reach the aquatic environment and that they could represent a risk to aquatic organisms and humans. We have studied the discharge of nano-TiO2 (nTiO2) to water for two case studies related to photocatalytic nanomaterials: A-The release of nTiO2 from two photocatalytic coatings under accelerated aging under a water flow and B-The release of nTiO2 though a filtration pilot plant from tap water containing 2 mg/L nanoparticles. Case A. The influence of environmental parameters (water matrix, UV-light) was investigated while the consequences of aging were evaluated under different endpoints, among them, the release of TiO2 nanoparticles. Despite that TiO2 emissions were observed for both coatings, only one of them presented mechanical damages. TiO2 concentrations up to 150.5 μg/L were detected in the aging water. Case B. Preliminary experiments were conducted at laboratory scale to determine optimum polymeric material as well as pore size. Among the common commercial materials PVDF showed the best performance. Two different industrial hollow fiber cartridges were tested with a pore size of 0.45 μm (microfiltration) and 0.03 μm (ultrafiltration). TiO2 was detected at an average concentration of 51 μg/L in the filtered water.Item Influence of menopause on adipose tissue clock gene genotype and its relationship with metabolic syndrome in morbidly obese women(2012-12) Hernandez-Morante, Juan José; Gomez-Santos, Cecilia; Margareto, Javier; Formiguera, Xavier; Martínez, Carlos Manuel; González, Raquel; Martínez-Augustín, Olga; Madrid, Juan Antonio; Ordovas, Jose María; Garaulet, Marta; GenéticaMenopausal women exhibit a loss of circadian coordination, a process that runs parallel with a redistribution of adipose tissue. However, the specific genetic mechanisms underlying these alterations have not been studied. Thus, the aim of the present study was to determine whether the development of menopause induces an alteration of the genes that control biological rhythms in human subcutaneous (SAT) and visceral (VAT) adipose tissue, and whether changes in clock gene expression are involved in the increased risk of developing metabolic syndrome (MetS), which is frequently associated with menopause. To this end, VAT and SAT biopsies were taken in pre- (n = 7) and postmenopausal (n = 7) women at similar hours in the morning. RNA was extracted, and a microarray analysis was made. Data were confirmed by quantitative real-time polymerase chain reaction. Western blot and immunohistochemical analysis were also performed. When clock gene expression was compared between both groups of women, data in SAT showed that expression of the core clock gene period3 was significantly higher in postmenopausal women, while casein kinase-1δ, E1A-binding protein and cAMP-responsive element were preferentially expressed in the premenopausal group. In VAT, period2 (PER2) and v-myc myelocytomatosis viral oncogene expressions were significantly higher in the postmenopausal group. Western blot analysis indicated that PER2 and PER3 protein expression was also increased in postmenopausal women. In addition, several genes, including PER2, were differentially expressed depending on whether or not the patient met the MetS criteria. We conclude that menopause transition induces several changes in the genotype of the adipose tissue chronobiological machinery related to an increased risk of developing MetS.