Oxygen photo-adsorption related quenching of photoluminescence in group-III nitride nanocolumns

GaN and InGaN nanocolumns of various compositions are studied by room-temperature photoluminescence (PL) under different ambient conditions. GaN nanocolumns exhibit a reversible quenching upon exposure to air under constant UV excitation, following a t−1/2 time dependence and resulting in a total reduction of intensity by 85–90%, as compared to PL measured in vacuum, with no spectral change. This effect is not observed when exposing the samples to pure nitrogen. We attribute this effect to photoabsorption and photodesorption of oxygen that modifies the surface potential bending. InGaN nanocolumns, under the same experimental conditions do not show the same quenching features: The high-energy part of the broad PL line is not modified by exposure to air, whereas a lower-energy part, which does quench by 80–90%, can now be distinguished. We discuss the different behaviors in terms of carrier localization and possible composition or strain gradients in the InGaN nanocolumns

Optimización de la producción de biomasa usando glicerol crudo, de una cepa mutante de Yarrowia lipolytica con actividad incrementada de lipasa

218-225The yeast Yarrowia lipolytica accumulates oils and is able to produce extracellular lipases when growing in different carbon sources including glycerol, the principal by-product of the biodiesel industry. In this study, biomass production of a novel mutant strain of Y. lipolytica was statistically optimized by Response Surface Methodology in media containing biodiesel-derived glycerol as main carbon source. This strain exhibited distinctive morphological and fatty acid profile characteristics, and showed an increased extracellular lipase activity. An organic source of nitrogen and the addition of 1.0 g/l olive oil were necessary for significant lipase production. Plackett-Burman and Central Composite Statistical Designs were employed for screening and optimization of fermentation in shaken flasks cultures, and the maximum values obtained were 16.1 g/l for biomass and 12.2 Units/ml for lipase, respectively. Optimized batch bioprocess was thereafter scaled in aerated bioreactors and the values reached for lipase specific activity after 95 percent of the glycerol had been consumed, were three-fold higher than those obtained in shaken flasks cultures. A sustainable bioprocess to obtain biomass and extracellular lipase activity was attained by maximizing the use of the by-products of biodiesel industry

Approaches in biotechnological applications of natural polymers

Natural polymers, such as gums and mucilage, are biocompatible, cheap, easily available and non-toxic materials of native origin. These polymers are increasingly preferred over synthetic materials for industrial applications due to their intrinsic properties, as well as they are considered alternative sources of raw materials since they present characteristics of sustainability, biodegradability and biosafety. As definition, gums and mucilages are polysaccharides or complex carbohydrates consisting of one or more monosaccharides or their derivatives linked in bewildering variety of linkages and structures. Natural gums are considered polysaccharides naturally occurring in varieties of plant seeds and exudates, tree or shrub exudates, seaweed extracts, fungi, bacteria, and animal sources. Water-soluble gums, also known as hydrocolloids, are considered exudates and are pathological products; therefore, they do not form a part of cell wall. On the other hand, mucilages are part of cell and physiological products. It is important to highlight that gums represent the largest amounts of polymer materials derived from plants. Gums have enormously large and broad applications in both food and non-food industries, being commonly used as thickening, binding, emulsifying, suspending, stabilizing agents and matrices for drug release in pharmaceutical and cosmetic industries. In the food industry, their gelling properties and the ability to mold edible films and coatings are extensively studied. The use of gums depends on the intrinsic properties that they provide, often at costs below those of synthetic polymers. For upgrading the value of gums, they are being processed into various forms, including the most recent nanomaterials, for various biotechnological applications. Thus, the main natural polymers including galactomannans, cellulose, chitin, agar, carrageenan, alginate, cashew gum, pectin and starch, in addition to the current researches about them are reviewed in this article.. }To the Conselho Nacional de Desenvolvimento Cientfíico e Tecnológico (CNPq) for fellowships (LCBBC and MGCC) and the Coordenação de Aperfeiçoamento de Pessoal de Nvíel Superior (CAPES) (PBSA). This study was supported by the Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of UID/BIO/04469/2013 unit, the Project RECI/BBB-EBI/0179/2012 (FCOMP-01-0124-FEDER-027462) and COMPETE 2020 (POCI-01-0145-FEDER-006684) (JAT)

Estimation of interferences in the determination of fructosamine of feline and canine serum

The fructosamine serum concentration reflects the degree of glycemic control obtained during a\npreceding period. Usually, the presence of hemoglobin or bilirrubin in blood samples, could cause\ninterferences in the laboratory analytical assays.Thus, we investigated the possible interferences\non fructosamine determinations in serum from healthy cats and dogs. To testing and quantify\nthe interference, we construct interferograms adding increased concentrations of hemoglobin\nor bilirrubin to serum pools of cats or dogs. We tested serum hemoglobin concentrations from\n0.19 to 7.5 g/l in feline sera and 0.16 to 6.10 g/l in canine sera. The bilirrubin testing was\ndone from 6 to 600 mg/l in both species sera. The results had shown a hemoglobin positive\nand additive interference in feline sera (?1.60 g/l) and a negative interference in canine sera\n(?1.20 g/l). In addition both species had shown positive and additive bilirrubin interferences\n(?30 mg/l for feline sera and ?150 mg/l for canine sera).Fil: Colla, C. Universidad Nacional de Rosario. Facultad de Ciencias Veterinarias. Cátedra de Farmacología y Terapéutica; ArgentinaFil: Rodriguez, J. Universidad Nacional de Rosario. Facultad de Ciencias Veterinarias. Cátedra de Farmacología y Terapéutica; ArgentinaFil: Rodriguez, J. Universidad Nacional de Rosario. Centro Binacional (Argentina-Italia) de Investigaciones en Criobiología Clínica y Aplicada; ArgentinaFil: Rabe, G. Universidad Nacional de Rosario. Facultad de Ciencias Veterinarias. Cátedra de Farmacología y Terapéutica; ArgentinaFil: Patalano, C. Universidad Nacional de Rosario. Facultad de Ciencias Veterinarias. Cátedra de Farmacología y Terapéutica; ArgentinaFil: Perassi, M. Universidad Nacional de Rosario. Facultad de Ciencias Veterinarias. Cátedra de Farmacología y Terapéutica; ArgentinaFil: Bordone, F. Universidad Nacional de Rosario. Facultad de Ciencias Veterinarias. Cátedra de Farmacología y Terapéutica; ArgentinaFil: Cerrutti, J. Universidad Nacional de Rosario. Facultad de Ciencias Veterinarias. Cátedra de Farmacología y Terapéutica; ArgentinaLa concentración de fructosamina en suero es útil para monitorear el control de la glucemia en\nun período precedente.En muestras de sangre, la presencia de hemoglobina y bilirrubina pueden\ncausar interferencias en técnicas analíticas diagnósticas. Por ello, el objetivo de este trabajo fue\nevaluar la posible interferencia al medir fructosamina sérica de gatos y perros clínicamente sanos.\nSe construyeron interferogramas, agregando concentraciones crecientes del posible interferente\na pools de sueros de ambas especies. Se estudiaron concentraciones de hemoglobina desde 0.19\na 7.5 g/l en felinos, y de 0.16 a 6.10 g/l en caninos. Para bilirrubina, desde 6 a 600 mg/l, en\nambas especies. Los resultados mostraron interferencia positiva y aditiva de hemoglobina en\nfelinos (?1.60 g/l) e interferencia negativa en caninos (?1.20 g/l). En ambas especies se observaron\ninterferencias positivas y aditivas para bilirrubina en el rango de concentraciones estudiadas\n(?30 mg/l para felinos y ?150 mg/l para caninos)

Migration and social mobility between Argentina and Spain : climbing the social hierarchy in the transnational space

Production of INCASI Project H2020-MSCA-RISE-2015 GA 691004This chapter analyses the relationship between migration and social mobility in Argentina and Spain from a transnational perspective focusing on two dimensions: the patterns of intergenerational social mobility of immigrants and natives in both countries; the social mobility strategies and trajectories of Galicians families in Buenos Aires and Argentinians, of Galician origin, who migrated to Galicia after the 2001 crisis. The chapter begins by contextualizing the migratory trends in Europe and Latin America. This is followed by a comparative study of how immigration impacts on the class structure and social mobility patterns in Argentina and Spain. Quantitative analysis techniques are used to study the intergenerational social mobility rates. The statistical analysis of stratification and social mobility surveys have been benchmarked against previous studies conducted in Argentina (Germani, G., Movilidad social en la sociedad industrial. EUDEBA, Buenos Aires, 1963; Dalle, P., Movilidad social desde las clases populares. Un estudio sociológico en el Área Metropolitana de Buenos Aires (1960-2013). CLACSO/Instituto de Investigaciones Gino Germani-UBA/CICCUS, Buenos Aires, 2016) and Spain (Fachelli, S., & López-Roldán, P., Revista Española de Sociología 26:1-20, 2017). Secondly, qualitative research methods are used to consider the social mobility strategies and class trajectories of migrant families. We analyse two fieldworks, developed in the framework of other research projects (based on 44 biographical and semi-structured interviews). These case studies were carried out with Galicians that migrated to Argentina between 1940 and 1960 and Argentinians, of Galician origin, who migrated to Galicia after the 2001 crisis

Transnational migration and urban informality: Ethnicity in Buenos Aires' informal settlements

Ethnicity is playing an increasingly important role in the ways in which informality is governed and regulated across cities in the global south. This raises concerns regarding the ensuing exclusion experienced by some groups of people living in informal settlements. In this paper I use the example of Buenos Aires, Argentina, to explore the extent to which ethnicity plays a role in the informal settlement. There is significant evidence that Argentina has gone through a process of de-ethnicisation, particularly at the national level. However, it is unclear whether this process is also evident at the level of the informal settlement. Drawing on a range of interviews, the paper finds that while grassroots organisations are de-ethnicising, the formal leadership of the informal settlement and to some extent also migrants reproduce ethnic divisions. The de-ethnicisation led by the state has therefore unequally percolated to the micro level

The Economic Crisis and Residential Electricity Consumption in Spanish Provinces: A Spatial Econometric Analysis

This paper presents an empirical analysis of residential electricity demand considering the existence of spatial effects. This analysis has been performed using aggregate panel data at the province level for 46 Spanish provinces for the period from 2001 to 2009. For this purpose, we estimated a log-log demand equation using a spatial autoregressive model with autoregressive disturbances (SARAR). The purpose of this empirical analysis is to determine the influence of price, income, and spatial spillovers on residential electricity demand in Spain. We are particularly interested in analyzing the impact of household disposable income variation across provinces observed during the economic crisis period from 2008-2009. The estimation results show relatively high income elasticity and relatively low price elasticity. Furthermore, the results show the presence of spatial effects in Spanish residential electricity consumption