Estudio de diferentes formulaciones de cementos de fosfato de calcio para regeneración ósea

El presente proyecto final de carrera se undamenta en la investigación del desarrollo de nuevos materiales de tipo cemento capaces de estimular la regeneración y reparación del tejido óseo. Se estudian tres formulaciones de cementos de fosfato de calcio, basados en el fosfato tricálcico a (a-TCP), con el objetivo de evaluar la diferencia del tamaño cristalino en una de ellas (serie 2) y el efecto de la inclusión de albumen (proteína derivada de la clara de huevo) en la composición de otra (serie 3), todo ello respecto a un patrón (serie 1). Las tres series de cemento se preparan previa caracterización fisico-química de los reactivos empleados. Se estudia el proceso de reacción, determinando los tiempos de fraguado y se caracterizan los cementos mediante las técnicas de difracción de rayos X y espectroscopía de infrarrojo, que revelan la conversión del a-TCP en hidroxiapatita deficiente en calcio (CDHA), muy similar a la hidroxiapatita biológica. Se realiza un estudio de la topografía superficial de los cementos con el objetivo de evaluar las diferencias de rugosidad, para ello se emplean técnicas como la microscopía electrónica de barrido y la microscopía óptica interferométrica entre otras, obteniéndose la menor rugosidad en la serie 2, de menor tamaño cristalino. Una vez caracterizadas las superficies con los valores de rugosidad respectivos se determina cual de ellas presenta mejor comportamiento biológico, a partir de cultivos celulares. Para ello se lleva a cabo un estudio in vitro de células osteoblásticas sobre los cementos con el fin de evaluar la posible citotoxicidad y biocompatibilidad de éstos. Además, se estudia la adhesión, proliferación y diferenciación celular en relación a la rugosidad superficial y composición de cada serie. Se realizan micrografías a lo largo de los ensayos mediante microscopía electrónica de barrido ambiental y microscopía electrónica de barrido. Los resultados obtenidos demuestran que ninguna de las series presenta signos de citotoxicidad. La serie 2, de menor tamaño cristalino, favorece la adhesión de los osteoblastos al igual que su diferenciación, sin embargo, se reduce la proliferación. La introducción de albumen en la composición del cemento aumenta la rugosidad considerablemente y mejora la proliferación osteoblástica y la diferenciación, siendo esta formulación la que mejores resultados presenta en este aspecto. Se realiza un estudio de significación estadística de los resultados obtenidos

Estudio de diferentes formulaciones de cementos de fosfato de calcio para regeneración ósea

El presente proyecto final de carrera se undamenta en la investigación del desarrollo de nuevos materiales de tipo cemento capaces de estimular la regeneración y reparación del tejido óseo. Se estudian tres formulaciones de cementos de fosfato de calcio, basados en el fosfato tricálcico a (a-TCP), con el objetivo de evaluar la diferencia del tamaño cristalino en una de ellas (serie 2) y el efecto de la inclusión de albumen (proteína derivada de la clara de huevo) en la composición de otra (serie 3), todo ello respecto a un patrón (serie 1). Las tres series de cemento se preparan previa caracterización fisico-química de los reactivos empleados. Se estudia el proceso de reacción, determinando los tiempos de fraguado y se caracterizan los cementos mediante las técnicas de difracción de rayos X y espectroscopía de infrarrojo, que revelan la conversión del a-TCP en hidroxiapatita deficiente en calcio (CDHA), muy similar a la hidroxiapatita biológica. Se realiza un estudio de la topografía superficial de los cementos con el objetivo de evaluar las diferencias de rugosidad, para ello se emplean técnicas como la microscopía electrónica de barrido y la microscopía óptica interferométrica entre otras, obteniéndose la menor rugosidad en la serie 2, de menor tamaño cristalino. Una vez caracterizadas las superficies con los valores de rugosidad respectivos se determina cual de ellas presenta mejor comportamiento biológico, a partir de cultivos celulares. Para ello se lleva a cabo un estudio in vitro de células osteoblásticas sobre los cementos con el fin de evaluar la posible citotoxicidad y biocompatibilidad de éstos. Además, se estudia la adhesión, proliferación y diferenciación celular en relación a la rugosidad superficial y composición de cada serie. Se realizan micrografías a lo largo de los ensayos mediante microscopía electrónica de barrido ambiental y microscopía electrónica de barrido. Los resultados obtenidos demuestran que ninguna de las series presenta signos de citotoxicidad. La serie 2, de menor tamaño cristalino, favorece la adhesión de los osteoblastos al igual que su diferenciación, sin embargo, se reduce la proliferación. La introducción de albumen en la composición del cemento aumenta la rugosidad considerablemente y mejora la proliferación osteoblástica y la diferenciación, siendo esta formulación la que mejores resultados presenta en este aspecto. Se realiza un estudio de significación estadística de los resultados obtenidos

Skill heterogeneity and market labour income inequality

Occupational choice models predict that, ceteris paribus, countries with higher dispersion of skill will have higher market labour income inequality. However, an extended conclusion from empirical research is that cross-country variations in dispersion of skill explain little of the variation in income inequality. This paper identifies factors related to production and organization technologies that moderate the relationship between dispersion of skill and dispersion of income in occupational choice equilibrium outcomes and that, if not properly accounted for, can bias the results of the empirical studies that explain dispersion of income as a function of dispersion of skill. In particular, comparing equilibrium outcomes from occupational choices in economies that differ in the distribution of skill and in the efficiency of supervision hierarchies, the paper can explain why the US and Sweden have similar labour productivity, but income inequality is higher in the US than in Sweden, and why productivity is lower and income inequality is higher in Spain than in Sweden

Evaluation of chemical fruit thinning efficiency using Brevis® (Metamitron) on apple trees (‘Gala’) under Spanish conditions

Thinning is an important technique in apple growing which is used to reduce the number of fruits per plant and achieve commercial fruit size and quality. The objective of this work was to evaluate the efficacy of one and two applications of the chemical thinner Brevis® in Gala apple applied at different fruit sizes and at different intervals between the first and second spray. The trials were conducted over two seasons from 2015 to 2016 in apple orchards of the IRTA experimental agricultural stations of Mas Badia and Lleida (Spain). One or two applications with Brevis® were applied at different fruit sizes (king fruit diameter ranging between 7.5 and 13.5 mm) and at a rate of 1.65 kg/ha for all treatments. Under the trial conditions, a Brevis® thinning effect was observed in all trials with a reduction in crop load, fruit set and number of fruits per tree which varied according to the number of applications. In addition, average fruit weight, color and diameter increased significantly with treatments in which Brevis® reduced the number of fruits per tree. The degree of abscission of Brevis® was highly dependent on night temperature and, for this reason, there was a high degree of variability between trials in terms of efficacy. Our results show that the number of days between applications was not as important a factor for Brevis® efficacy as the difference in night temperature in the days immediately after its application.info:eu-repo/semantics/acceptedVersio

Brevis thinning efficacy at different fruit size and fluorescence on ‘Gala’ and ‘Fuji’ apples

Brevis thinning efficacy depends on climatic and cultivar conditions. The objective of this work was to evaluate the efficacy of one application of Brevis in ‘Gala’ and ‘Fuji’ apple applied at different fruit sizes (fruit king diameter ranging between 6.5 and 21.5 mm) and to determine which fruit diameters were most sensitive to Brevis application. Trials were conducted over two seasons from 2015 to 2016 in apple orchards in Lleida (Spain). Photosynthesis inhibition caused by Brevis was also analysed and measured, using chlorophyll fluorescence and biexponential pharmacokinetic models. In 2016, for all Brevis treatments and an untreated control, quantum yield (Qy) was measured in all leaves in different shoots, with photosynthesis inhibition and its evolution analysed in three sections (closest to branch, mid-shoot and vegetative section). Under the trial conditions, Brevis thinning effect was observed at king fruit diameters from 9 to 19 mm, with maximum efficacy observed in the 11.5–14 mm range. However, susceptibility to Brevis differed between varieties and years. The fluorescence analysis using a biexponential equation showed adequate fits and the calculated values correlated well with the measured Qy(%) values. The area under curve per day analysis showed that, at the same application dose, fluorescence inhibition decreased with increasing fruit diameter. The fluorescence analysis of shoot sections four days after Brevis application showed differences between varieties, with the inhibition caused by Brevis higher in ‘Gala’ than in ‘Fuji’. However, this analysis showed no significant differences in ‘Gala’, with all sections showing similar inhibition (27%–35%). By contrast, ‘Fuji’ showed different inhibition values in the different sections. The vegetative section showed the significantly highest inhibition, and the zone nearest the branch the lowest.info:eu-repo/semantics/acceptedVersio

Hail nets do not affect the efficacy of metamitron for chemical thinning of apple tree

Hail nets reduce photosynthetically active radiation (PAR) and alter the environment under the netting in apple orchards. Thus, we investigated the effect of nets on the efficacy of metamitron, a short-term photosynthesis inhibitor used for fruit thinning. The objective of this study was to evaluate the effect of the netting and metamitron on thinning efficacy, yield, fruit quality and chlorophyll fluorescence in three apple (Malus domestica Borkh.) cultivars. One or two metamitron applications at different doses or rates were applied the tree under different coloured nets. The reduction of PAR was highest with black nets (19%-22%), followed by green (13%-15%) and white nets (6%-11%). There were no significant differences (P> 0.05) in fruit weight or size with or without nets. Double applications of metamitron increased average fruit fresh weight and reduced the fruit set over four experiments. In contrast, single applications were less effective. In two experiments, thinning was associated with lower yields. However, there was no effect in the other two experiments. The double treatments tended to increase the percentage of the crop with fruit larger than 70 mm in diameter. All thinning strategies showed similar inhibition in fluorescence, with the only observed significant differences between treatments occurring when using a single or double application. The results show that netting does not affect the response to thinning with metamitron.info:eu-repo/semantics/acceptedVersio

Effect of different application rates of metamitron as fruitlet chemical thinner on thinning efficacy and fluorescence inhibition in Gala and Fuji apple

Crop thinning is an important and difficult agricultural practice. Knowing the effect of the application dose of a product is a crucial element of any thinning program. The aims of this study were to investigate the effect of different metamitron doses on Gala and Fuji apples applied at fruit king diameters of between 8 and 10 mm and to determine fluorescence inhibition at the different application rates. Trials were conducted over two seasons from 2015 to 2016 in apple orchards in Lleida (Spain). Photosynthesis inhibition caused by metamitron was also analysed and measured, using chlorophyll fluorescence and biexponential pharmacokinetic models. Under the trial conditions, the application of metamitron reduced final fruit set, number of fruits per tree and crop load depending on the application rate. A dose effect was observed in all yield parameters. Moreover, when metamitron showed high efficacy, there was an improvement in fruit weight, coloration and diameter. The estimated parameters A, α and B using a biexponential equation were related with final fruit set, however the period of inhibition has to be finished before prediction can be made of metamitron efficacy in the year. The fluorescence analysis showed a dose effect, with metamitron dose increasing inhibition. Additionally, the same result was also observed in the area under curve analysis, with metamitron dose reducing the area and inhibition increasing. In all yield parameters, the fluorescence and area under curve analyses showed differences between cultivars, with the inhibition caused by metamitron higher in Gala than in Fuji. Moreover, differences between years were observed. 2015 was warmer than 2016, and the higher temperatures increased the thinning efficacy of metamitron.This study was supported financially by project INIA (RTA2012-00116-00-00) in collaboration with ADAMA-Spain

Evaluation of chemical fruit thinning efficiency using Brevis® (Metamitron) on apple trees (‘Gala’) under Spanish conditions

Thinning is an important technique in apple growing which is used to reduce the number of fruits per plant and achieve commercial fruit size and quality. The objective of this work was to evaluate the efficacy of one and two applications of the chemical thinner Brevis® in Gala apple applied at different fruit sizes and at different intervals between the first and second spray. The trials were conducted over two seasons from 2015 to 2016 in apple orchards of the IRTA experimental agricultural stations of Mas Badia and Lleida (Spain). One or two applications with Brevis® were applied at different fruit sizes (king fruit diameter ranging between 7.5 and 13.5 mm) and at a rate of 1.65 kg/ha for all treatments. Under the trial conditions, a Brevis® thinning effect was observed in all trials with a reduction in crop load, fruit set and number of fruits per tree which varied according to the number of applications. In addition, average fruit weight, color and diameter increased significantly with treatments in which Brevis® reduced the number of fruits per tree. The degree of abscission of Brevis® was highly dependent on night temperature and, for this reason, there was a high degree of variability between trials in terms of efficacy. Our results show that the number of days between applications was not as important a factor for Brevis® efficacy as the difference in night temperature in the days immediately after its application.This study was supported financially by project INIA (Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (Spain)) (RTA2012-00116-00-00) in collaboration with ADAMA-Spain