245 research outputs found
Photocatalytic activity for NO degradation by construction materials: Parametric study and multivariable correlation
Various standards have been published in an effort to rationalize and unify the evaluation and quantification of photocatalytic activity. The experimental conditions stated in the published standards and test methods differ in many aspects that make it very difficult to compare different results. This paper focuses on the influence of the different parameters involved in the photocatalytic process. The photocatalytic active material consists of white mortar, surface coated by TiO2. The activity has been determined by quantifying the photocatalytic oxidation of NO. In the studied concentration interval the kinetics was estimated by a first order reaction. The influence on the activity by the relative humidity, temperature, irradiance, contaminant concentration and catalyst load has been studied. Most influent parameters are the catalyst load and light intensity until reaching plateau values at higher amount and intensity. Humidity influence the activity above 40% RH and an increased temperature lowers the activity. A global empirical correlation, including the mentioned variables, has been developed, allowing the determination of the photocatalytic activity at different environmental conditions (within the constraints of this research) and, when necessary, for comparison with reference conditions
Histochemistry evaluation of the oxidative stress and the antioxidant status in Cu-supplemented cattle
The aim of this paper is to evaluate at a histopathological level the effect of the most commonly used copper (Cu) supplementation (15 mg/kg dry matter (DM)) in the liver of intensively reared beef cattle. This was done by a histochemistry evaluation of (i) the antioxidant capacity in the liver – by the determination of metallothioneins (MT) and superoxide dismutase (SOD) expression – as well as (ii) the possible induction of oxidative damage – by the determination of inducible nitric oxide synthase (iNOS), nitrotyrosine (NITT), malondialdehyde (MDA) and 8-oxoguanine (8-oxo) – that (iii) could increase apoptotic cell death – determined by cytochrome-c (cyto-c), caspase 1 (casp1) and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL). Liver samples from Cu-supplemented (15 mg Cu sulphate/kg DM, n = 5) and non-supplemented calves (n = 5) that form part of other experiments to evaluate Cu status were collected at slaughter and processed for immunohistochemistry and TUNEL. MT expression was diffuse and SOD showed slight changes although without statistical significance. iNOS and NITT positive (+) cells significantly increased, mainly around the central veins in the animals from the Cu-supplemented group, whereas no differences were appreciated for the rest of the oxidative stress and apoptosis markers. Under the conditions of this study, which are the conditions of the cattle raised in intensive systems in NW Spain and also many European countries, routinely Cu supplementation increased the risk of the animals to undergo subclinical Cu toxicity, with no significant changes in the Cu storage capacity and the antioxidant defensive system evaluated by MT and SOD expression, but with a significant and important increase of oxidative damage measured by iNOS and NITT. The results of this study indicated that iNOS and NITT could be used as early markers of initial pathological changes in the liver caused by Cu supplementation in cattle, although more studies in cattle under different levels of Cu supplementation are neededThis work was supported by the Xunta de Galicia (Spain) through contract 07MRU030261PR and by a research grant MarÃa Barbeito awarded to M. GarcÃa-Vaquero by the Dirección Xeral de Investigación, Desenvolvemento e Innovación from Xunta de Galicia and to FSE (Fondo Social Europeo) funds through Programa de Recursos Humanos, do Plan Galego de Investigación, Desenvolvemento e Innovación Tecnolóxica de GaliciaS
Implant platform switching concept: an updated review
Purpose: To review published articles dealing with platform switched implants in order to assess survival rates and clarify their influence both on marginal bone loss around the cervical region of the implant and on soft tissue aesthetics.Material and Methods: PubMed and GallileUM databases were used to identify any studies or clinical cases involving implant platform switching published between January 2000 and August 2008. Studies both of human beings and animals were reviewed whenever they included the relevant implant diameter, length, surface and connection data.Results: Twelve studies of platform switching in humans (75%) and in animal models (25%) were evaluated.Mean implant length was found to be 11.66 ± 0.2 SD mm and mean diameter was 4.9± 0.52 SD mm.Conclusion: It was shown that platform switching helps to prevent crestal bone loss after implant placement and helps obtain satisfactory aesthetic result
Evaluation of organic, conventional and intensive beef farm systems: health, management and animal production
The overall aim of the present study was to analyse and compare organic beef cattle farming in Spain with intensive and conventional systems. An on-farm study comparing farm management practices and animal health was carried out. The study also focussed on a slaughterhouse analysis by comparing impacts on the safety and quality of the cattle products. Twenty-four organic and 26 conventional farms were inspected, and farmers responded to a questionnaire that covered all basic data on their husbandry practices, farm management, veterinary treatments and reproductive performance during 2007. Furthermore, data on the hygiene and quality of 244, 2596 and 3021 carcasses of calves from organic, intensive and conventional farms, respectively, were retrieved from the official yearbook (2007) of a slaughterhouse. Differences found between organic and conventional farms across the farm analysis did not substantially reflect differences between both farm types in the predominant diseases that usually occur on beef cattle farms. However, calves reared organically presented fewer condemnations at slaughter compared with intensive and to a lesser extent with conventionally reared calves. Carcass performance also reflected differences between farm type and breed and was not necessarily better in organic farmsThis study was supported by the Xunta de Galicia (Spain;PGIDT02RA6261001PR) and I.B.P. received a research fellow-ship (AP2003-3835) from the Ministry of Science of SpainS
Serum-Metaboliten-Konzentrationen und Enzymaktivitäten in mit verschiedenen Futtermittelarten mit hohem Getreideanteil gefütterten Mastbullenkälbern
Between the ages of 23 and 35 weeks, various serum metabolites and enzymes were
monitored in three 10-animal groups of double-muscled Belgian Blue bull calves maintained
in a feedlot in Galicia (NW Spain) on high-grain finishing diets that mainly differed in whether
the grain used was predominantly maize (group M), predominantly barley (group B), or a
mixture of maize and barley in approximately equal proportions (group MB). The parameters
determined were glucose, non-esterified fatty acids (NEFA), total serum protein concentration
(TSP), albumin, serum urea nitrogen (SUN), creatinine, aspartate aminotransferase (AST),
and gamma-glutamyltransferase (GGT). Throughout the study period, all these parameters
remained within the physiological ranges for beef under intensive conditions, and no animal
ever showed clinical symptoms of ruminal alterations; indicating that none of these highgrain diets were detrimental to animal health. Although average serum NEFA, creatinine,
albumin, AST and GGT levels all differed among groups, only AST can be considered as
possible age-independent marker of grain-type-related metabolic alterations, since the
other parameters all showed significant time×group interaction. In terms of this parameter,
animals fed a MB diet behaved similarly to those fed a B diet. The absence of between-group
differences in blood glucose level may reflect a genetic characteristic of this double-muscled
breed. Our results, in conjunction with the best productive results obtained in animals fed
de B-diet, aim us to suggest that the risk of an acidogenic diet would depend strongly on the
nutritional management (in terms of crude protein (CP) and quality of straw in the ration) and
not only the type of grain.Zwischen dem Alter von 23 und 35 Wochen wurde ein Monitoring durchgeführt der
verschiedenen Serum-Metaboliten und Enzyme mit drei Gruppen zu jeweils 10 Weißblauen
Belgier-Bullenkälbern mit starker Muskelfülle, die in einer Mastparzelle in Galizien (NW Spanien) mit Mastfuttermittelarten mit hohem Getreideanteil gehalten wurden, die sich
hauptsächlich darin unterschieden, dass das verwendete Getreide überwiegend aus Mais
(Gruppe M), überwiegend aus Gerste (Gruppe B) oder aus einem Gemisch von Mais und
Gerste zu ungefähr gleichen Teilen (Gruppe MB) bestand. Die nachgewiesenen Parameter
waren Glukose, nicht veresterte Fettsäuren (NEFA), Serum-Gesamtproteinkonzentration
(TSP), Albumin, Serum-Harnstoffstickstoff (SUN), Creatinin, Aspartataminotransferase (ASTZ)
und γ-Glutamyltransferase (GGT). Während des Untersuchungszeitraums blieben diese
Parameter durchwegs innerhalb des für Rindfleisch unter intensiven Haltungsbedingungen
physiologischen Bereichs, und kein Tier zeigte zu irgendeiner Zeit klinische Symptome
einer Rumen-Veränderung, so dass keines dieser Futtermittel mit hohem Getreideanteil
der tierischen Gesundheit abträglich war. Obwohl die durchschnittlichen Konzentrationen
von NEFA, Creatinin, Albumin, AST und GGT im Serum in den Gruppen alle unterschiedlich
waren, kann nur AST als möglicher altersunabhängiger Marker von getreidebedingten
Stoffwechselveränderungen betrachtet werden, da die anderen Parameter alle eine
signifikante Wechselwirkung zwischen Zeit und Gruppe zeigten. Im Hinblick auf diese
Parameter verhielten sich Tiere, an die ein MB-Futtermittel verfüttert wurde, wie diejenigen,
an die ein B-Futtermittel verfüttert wurde. Das Fehlen von Intergruppenunterschieden
hinsichtlich des Blut-Glukosespiegels könnte ein genetisches Merkmal dieser Rasse mit starker
Muskelfülle widerspiegeln. Unsere Ergebnisse, zusammen mit den besten, mit Tieren, denen
das B-Futter verfüttert wurde, erhaltenen Nutzergebnissen veranlassen uns zu dem Vorschlag,
dass das Risiko einer azidogenen Fütterung stark vom Fütterungsmanagement (hinsichtlich
Roheiweiß (CP) und Qualitätsstroh in der Ration) und nicht nur vom Getreidetyp abhängt.This work was supported by the Xunta de Galicia (Spain) through grant XUGA 2002/CG320S
TiO2 and TiO2-SiO2 coated cement: Comparison of mechanic and photocatalytic properties
peer reviewedAn increasingly known application of nanomaterials in the construction industry is related to the photoactivity ability of semiconductors, where nano-anatase TiO2 is perhaps the most well-known photocatalytic semiconductor and one which possesses a strong oxidizing capability. To analyze the photo-efficiency of four TiO2 coatings and the effect of SiO2 interlayer on the mechanic and photocatalytic activity in Rhodamine B (RhB) and NOx photodegradation, two photocatalytic cement series have been prepared. First, cement mortar was coated with three commercial TiO2 suspensions (GG1, GC7 and CG13) and a home-made titania sol-gel (TEA), and secondly an insertion of a SiO2 layer was applied on cement surface before spraying the TiO2 layer.All studied TiO2-cements exhibited a significant RhB and NOx photodegradation, arising almost total RhB molar conversions, and upper 53% for NOx photo-oxidation respectively. Nevertheless, although SiO2 layer deposited in between mortar and TiO2-cement did not stabilize the commercial TiO2 coatings, a good adhesion was observed when silica was applied joint to the home-made titania gel (TEA), probably as a consequence of the interactions encountered between SiO2 and TiO2 gels. CG7-Si-Cem exhibited high rate at shorter irradiation times, but TEA-Cem and TEA-Si-Cem can be considered as very interesting and potential photocatalytic mortars due to useful mechanical properties, with a very good coatings adhesion that provides promising outdoor use, and good photo-efficiencies in RhB and NOx photo-oxidation
Protocolo de valorización de residuos en la fabricación de materiales de base cemento: sedimentos dragados como componente de hormigón autocompactante
[ES] La incorporación de los materiales procedentes del dragado como materia prima en la
industria de la construcción es uno de los principales objetivos del sector, dada la creciente
demanda de este tipo de materiales y la cada vez mayor escasez de los recursos procedentes
del interior. La mayor parte de las investigaciones realizadas se han centrado en la
reutilización de residuos industriales y de demolición, sin embargo, el uso de materiales
procedentes de dragado no ha sido tan ampliamente estudiado y no se han encontrado
protocolos para evaluar de forma sistemática su viabilidad como materia prima en la
fabricación de materiales con base cemento. En este sentido, el principal objetivo de esta
investigación es el diseño de un protocolo que permita evaluar la idoneidad de un residuo
procedente de un puerto español como componente de un hormigón autocompactante
(SCC). Para ello se realizará un completo análisis quÃmico, mineralógico y granulométrico
del sedimento y, una vez comprobada su idoneidad, el éxito de su inclusión como parte del
SCC se estudiará mediante ensayos de durabilidad y de compatibilidad medioambiental.
Estos ensayos mostrarán que las propiedades del SCC obtenido están de acuerdo con las
esperadas para uno convencional fabricado con filler silÃceo normal.Esta investigación formó parte del proyecto CLEAM CENIT patrocinado por el Centro Español de Desarrollo Tecnológico Industrial (CDTI) dentro del programa CENIT y ha sido posible gracias al apoyo económico del CDTI y A.I.E. (Asociación de Interés Económico) CLEAM-CENIT. Mención especial a DRAGADOS, que fue el responsable de la coordinación industrial de la tarea en la que se desarrolló este trabajo. Los autores también agradecen al Ministerio de EconomÃa y Competitividad la financiación aportada por el proyecto BIA 2011-25653 '' TELEPASSCLOR '' otorgado en el marco del Plan Nacional de I + D + iRozas, F.; Castillo Talavera, A.; MartÃnez Sierra, I.; Castellote Armero, M. (2018). Protocolo de valorización de residuos en la fabricación de materiales de base cemento: sedimentos dragados como componente de hormigón autocompactante. En HAC 2018. V Congreso Iberoamericano de hormigón autocompactable y hormigones especiales. Editorial Universitat Politècnica de València. 291-300. https://doi.org/10.4995/HAC2018.2018.5637OCS29130
Heavy ion beam measurement of the hydration of cementitious materials
The setting and development of strength of Portland cement concrete depends upon the reaction of water with various phases in the Portland cement. Nuclear resonance reaction analysis (NRRA) involving the 1H(15N,α,γ)12C reaction has been applied to measure the hydrogen depth profile in the few 100 nm thick surface layer that controls the early stage of the reaction. Specific topics that have been investigated include the reactivity of individual cementitious phases and the effects of accelerators and retarders
Alzheimer’s disease mutant mice exhibit reduced brain tissue stiffness compared to wild-type mice in both normoxia and following intermittent hypoxia mimicking sleep apnea
Background: Evidence from patients and animal models suggests that obstructive sleep apnea (OSA) may increase the risk of Alzheimer’s disease (AD) and that AD is associated with reduced brain tissue stiffness.
Aim: To investigate whether intermittent hypoxia (IH) alters brain cortex tissue stiffness in AD mutant mice exposed to IH mimicking OSA.
Methods: Six-eight month old (B6C3-Tg(APPswe,PSEN1dE9)85Dbo/J) AD mutant mice and wild-type (WT) littermates were subjected to IH (21% O2 40 s to 5% O2 20 s; 6 h/day) or normoxia for 8 weeks. After euthanasia, the stiffness (E) of 200-μm brain cortex slices was measured by atomic force microscopy.
Results: Two-way ANOVA indicated significant cortical softening and weight increase in AD mice compared to WT littermates, but no significant effects of IH on cortical stiffness and weight were detected. In addition, reduced myelin was apparent in AD (vs. WT), but no significant differences emerged in the cortex extracellular matrix components laminin and glycosaminoglycans when comparing baseline AD and WT mice.
Conclusion: AD mutant mice exhibit reduced brain tissue stiffness following both normoxia and IH mimicking sleep apnea, and such differences are commensurate with increased edema and demyelination in AD.This work was supported in part by Fundació Marató TV3 (20143231), the Spanish Ministry of Economy and Competitiveness—Instituto de Salud Carlos III (FIS-PI14/00004, FIS-PI14/00280) and SEPAR (139/2015). This work was partially funded by the CERCA Programme of Generalitat de Catalunya
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