293 research outputs found
Dispositivo impactador de laboratorio para la determinación de la firmeza en fruta: una nueva versión.
Se ha desarrollado una nueva versión de un dispositivo impactador para obtener un sistema versátil y de fácil manejo. La resolución, la precisión y la relación señal-ruido son mayores en el nuevo sistema que en prototipos anteriores. Se ha realizado un diseño de experimentos con diferentes materiales usando el nuevo y el antiguo impactador para comprobar las mejoras conseguidas
New version of a laboratory impact device for firmness sensing of fruits.
Results of previous studies conducted by different researchers have shown that impact techniques can be used to evaluate firmness (Delwiche et al., 1989; Delwiche et al.;1996; Jaren et al., 1992; Ruiz Altisent et al., 1996). To impact the fruit with a small spherical impactor of known mass and radius of curvature and measure the acceleration of the impactor is a technique described by Chen et al. (1985) and used by several researchers for sensing fruit firmness (Jaren et al., 1992; Correa et al.; 1992). The advantages of this method vs. a force sensor that measures the force as a function of time is that the measured impact-acceleration response is independent of the fruit mass and is less sensitive to the variation in the radius of curvature of the fruit (Chen et al., 1996). Ruiz Altisent et al. (1993) developed and used a 50 g impactor with a 19 mm diameter spherical tip, dropping from different height for fruits (apples, pears, avocados, melons, peaches ...). Another impact device for firmness sensing of fruits was developed by Chen and Ruiz Altisent (1996). They designed and fabricated an experimental low-mass impact sensor for high-speed sensing of fruit firmness. The impactor consisted of a semi-spherical impacting tip attached to the end (near the centre of percussion) of a pivoting arm. Impact is done by swinging the impactor to collide with the fruit. It has been implemented for on-line use. In both devices a small accelerometer is mounted behind the impacting tip. Lateral impactor and vertical impactor have been used in laboratory and the results from non-destructive impact tests have contributed to standardise methods to measure fruit firmness: Barreiro (1992) compared impact parameters and results of Magness-Taylor penetration tests for apples, pears, apricots [and peaches; Agulheiro (1994) studied the behaviour of the impact parameters during seven weeks of cold storage of two melon varieties; Ortiz (1998) used low energy impact and NIR procedures to segregate non crispy, non firm and soft peaches. Steinmetz (1996) compared various non-destructive firmness sensors, based on sound, impact and micro-deformation
Evaluation of soil mechanic resistance and seed depth placement in a maize crop seed under different soil management practices
Com o objetivo de estudar a influência da resistência mecânica do solo na distribuição vertical de semente obtida por semeadores numa cultura de milho, realizou-se na campanha de 2011 um estudo de campo na região do Alentejo, sendo a operação de sementeira feita sob diferentes praticas culturais: mobilização convencional, mobilização mÃnima e sementeira direta. Em sementeira direta foram ainda testadas duas velocidades de trabalho, 4 km-1 e 6 km-1. A profundidade de sementeira foi determinada a partir da medição do comprimento do mesocótilo do milho após a emergência da cultura. A média, desvio padrão, coeficiente de variação e correlação dos valores de resistência ao rompimento do solo e profundidade de sementeira foram determinados. Os resultados demonstraram que independentemente da pratica cultural utilizada se verificou uma correlação negativa entre os valores encontrados para a resistência ao rompimento do solo e os valores de profundidade de deposição da semente, sendo o valor mais acentuado na condição de sementeira direta (r = - 0.77) à velocidade de trabalho de 4 km-1. A melhor performance de sementeira foi conseguida em sementeira direta com o aumento de velocidade de trabalho de 4 para 6 km-1 com um coeficiente de variação de 10.1%. A análise de variância demonstrou haverem diferenças significativas nas profundidades de sementeira causadas pela resistência do solo e pela velocidade de trabalho do semeador de sementeira direta
Calibración de una nariz electrónica tipo QCM y relación con las especificaciones para la calidad de la pera.
Las microbalanzas de cristal de cuarzo (QCM), son mecanismos piezoeléctricos, para transformarlos en sensores quÃmicos es necesario recubrirlos con una capa de material capaz de capturar las moléculas del ambiente. Cuando una masa es adsorbida sobre la superficie del cristal, la frecuencia de oscilación cambia en proporción a la cantidad de masa (Di Natale et al. 1997). La respuesta de los sensores depende de numerosos factores que pueden ser difÃciles de controlar, tales como la temperatura y la humedad del gas portador. Todos estos factores producen cambios en la selectividad de los sensores que afectan a la reproducibilidad de las medidas. A pesar de la existencia de numerosos estudios no existe ningún procedimiento establecido para la calibración de las QCM en relación con la sensibilidad necesaria en los sensores para el aseguramiento de la calidad en pera o en otras frutas
Ubr1-induced selective endophagy/autophagy protects against the endosomal and Ca2+-induced proteostasis disease stress
The cellular defense mechanisms against cumulative endo-lysosomal stress remain incompletely understood. Here, we iden tify Ubr1 as a protein quality control (QC) E3 ubiquitin-ligase that counteracts proteostasis stresses by facilitating endosomal cargo-selective autophagy for lysosomal degradation. Astrocyte regulatory cluster membrane protein MLC1 mutations cause endosomal compartment stress by fusion and enlargement. Partial lysosomal clearance of mutant endosomal MLC1 is accomplished by the endosomal QC ubiquitin ligases, CHIP and Ubr1 via ESCRT-dependent route. As a consequence of the endosomal stress, a supportive QC mechanism, dependent on both Ubr1 and SQSTM1/p62 activities, targets ubiquit inated and arginylated MLC1 mutants for selective endosomal autophagy (endophagy). This QC pathway is also activated for arginylated Ubr1-SQSTM1/p62 autophagy cargoes during cytosolic Ca2+-assault. Conversely, the loss of Ubr1 and/or arginylation elicited endosomal compartment stress. These fndings underscore the critical housekeeping role of Ubr1 and arginylation-dependent endophagy/autophagy during endo-lysosomal proteostasis perturbations and suggest a link of Ubr1 to Ca2+ homeostasis and proteins implicated in various diseases including cancers and brain disorder
Comparison of zebrafish and mice knockouts for Megalencephalic Leukoencephalopathy proteins indicates that GlialCAM/MLC1 forms a functional unit
[Abstract]
Background: Megalencephalic Leukoencephalopathy with subcortical Cysts (MLC) is a rare type of leukodystrophy characterized by astrocyte and myelin vacuolization, epilepsy and early-onset macrocephaly. MLC is caused by mutations in MLC1 or GLIALCAM, coding for two membrane proteins with an unknown function that form a complex specifically expressed in astrocytes at cell-cell junctions. Recent studies in Mlc1−/− or Glialcam−/− mice and mlc1−/− zebrafish have shown that MLC1 regulates glial surface levels of GlialCAM in vivo and that GlialCAM is also required for MLC1 expression and localization at cell-cell junctions.
Methods: We have generated and analysed glialcama−/− zebrafish. We also generated zebrafish glialcama−/− mlc1−/− and mice double KO for both genes and performed magnetic resonance imaging, histological studies and biochemical analyses.
Results: glialcama−/− shows megalencephaly and increased fluid accumulation. In both zebrafish and mice, this phenotype is not aggravated by additional elimination of mlc1. Unlike mice, mlc1 protein expression and localization are unaltered in glialcama−/− zebrafish, possibly because there is an up-regulation of mlc1 mRNA. In line with these results, MLC1 overexpressed in Glialcam−/− mouse primary astrocytes is located at cell-cell junctions.
Conclusions: This work indicates that the two proteins involved in the pathogenesis of MLC, GlialCAM and MLC1, form a functional unit, and thus, that loss-of-function mutations in these genes cause leukodystrophy through a common pathway.Ministerio de Ciencia e Innovación; SAF2015–70377Ministerio de Ciencia e Innovación; RTI2018–093493-B-I00Generalitat de Catalunya; SGR2014–1178Generalitat de Catalunya; SGR014–2016Instituto de Salud Carlos III; PI16/00267-R-Fede
Socio-economic status and the risk of developing hand, hip or knee osteoarthritis: a region-wide ecological study
SummaryObjectiveTo determine the association between socio-economic status (SES) and risk of hand, hip or knee osteoarthritis (OA) at a population level.DesignRetrospective ecological study using the System for the Development of Research in Primary Care (SIDIAP) database (primary care anonymized records for >5 million people in Catalonia (Spain)). Urban residents >15 years old (2009–2012) were eligible. Outcomes: Validated area-based SES deprivation index MEDEA (proportion of unemployed, temporary workers, manual workers, low educational attainment and low educational attainment among youngsters) was estimated for each area based on census data as well as incident diagnoses (ICD-10 codes) of hand, hip or knee OA (2009–2012). Zero-inflated Poisson models were fitted to study the association between MEDEA quintiles and the outcomes.ResultsCompared to the least deprived, the most deprived areas were younger (43.29 (17.59) vs 46.83 (18.49), years (Mean SD), had fewer women (49.1% vs 54.8%), a higher percentage of obese (16.2% vs 8.4%), smokers (16.9% vs 11.9%) and high-risk alcohol consumption subjects (1.5% vs 1.3%). Compared to the least deprived, the most deprived areas had an excess risk of OA: age-sex-adjusted Incidence Rate Ratio (IRR) 1.26 (1.11–1.42) for hand, 1.23 (1.17–1.29) hip, and 1.51 (1.45–1.57) knee. Adjustment for obesity attenuated this association: 1.06 (0.93–1.20), 1.04 (0.99–1.09), and 1.23 (1.19–1.28) respectively.ConclusionsDeprived areas have higher rates OA (hand, hip, knee). Their increased prevalence of obesity accounts for a 50% of the excess risk of knee OA observed. Public health interventions to reduce the prevalence of obesity in this population could reduce health inequalities
Comparison of zebrafish and mice knockouts for Megalencephalic Leukoencephalopathy proteins indicates that GlialCAM/MLC1 forms a functional unit
Background: Megalencephalic Leukoencephalopathy with subcortical Cysts (MLC) is a rare type of leukodystrophy characterized by astrocyte and myelin vacuolization, epilepsy and early-onset macrocephaly. MLC is caused by mutations in MLC1 or GLIALCAM, coding for two membrane proteins with an unknown function that form a complex specifically expressed in astrocytes at cell-cell junctions. Recent studies in Mlc1-/- or Glialcam-/- mice and mlc1-/- zebrafish have shown that MLC1 regulates glial surface levels of GlialCAM in vivo and that GlialCAM is also required for MLC1 expression and localization at cell-cell junctions. Methods: we have generated and analysed glialcama-/- zebrafish. We also generated zebrafish glialcama-/- mlc1-/- and mice double KO for both genes and performed magnetic resonance imaging, histological studies and biochemical analyses. Results: glialcama-/- shows megalencephaly and increased fluid accumulation. In both zebrafish and mice, this phenotype is not aggravated by additional elimination of mlc1. Unlike mice, mlc1 protein expression and localization are unaltered in glialcama-/- zebrafish, possibly because there is an up-regulation of mlc1 mRNA. In line with these results, MLC1 overexpressed in Glialcam-/- mouse primary astrocytes is located at cell-cell junctions. Conclusions: this work indicates that the two proteins involved in the pathogenesis of MLC, GlialCAM and MLC1, form a functional unit, and thus, that loss-of-function mutations in these genes cause leukodystrophy through a common pathway
Validación del método de elaboración tradicional del extracto de vainilla (Vanilla planifolia A.) en la Sierra de Otontepec
El objetivo del trabajo fue evaluar el método de elaboración tradicional de los extractos elaborados con refino artesanal, procedentes de la región de la Sierra de Otontepec Veracruz, con el propósito de conocer sus caracterÃsticas y generar información para determinar las ventajas de la concentración de vainillina que presenta cada una de las muestras analizadas. Se obtuvieron los perfiles quÃmicos y se identificaron compuestos  quÃmicos  utilizando  columnas  cromatografÃas  además  del  perfil  quÃmico  general, encontrando que el contenido de alcohol en los extractos, que elaboran los productores cuenta únicamente con el 14% de alcohol y lo mencionado en la NMX-FF-074-1996 dice que no debe ser menor del 30% por lo que no cumple con este requisito. Con respecto al contenido de vainillina los contenidos variaron de 348 a un 8,447 % (pm) por lo que cumplen con la Norma Oficial Mexicana que señala que el contenido mÃnimo de los extractos debe ser de 2,49 % en adelante, por lo tanto los extractos regionales se encuentran dentro de los parámetros y son aptos para su venta
Le gisement pléistocène moyen de Galeria Pesada (Estrémadure, Portugal) : premiers résultats
Les fouilles de la grotte de Galeria Pesada (complexe karstique d’Almonda, Torres Novas) livrent de riches assemblages lithiques et osseux datés du Pléistocène moyen final (fouilles 1997-1999). Les ensembles lithiques sont caractérisés par une combinaison d’outils classiques de l’Acheuléen, d’une abondante série d’outils bifaciaux (foliacés, petits bifaces asymétriques, Keilmesser, etc.) et de nombreux racloirs, souvent en quartz. Cette industrie n’a pas d’équivalent jusqu’à présent dans la Péninsule ibérique. Elle est associée à une faune dominée par les Cervidés et les Equidés dont les ossements présentent un fort pourcentage de marques de boucherie, démontrant une exploitation intensive (consommation) des carcasses par les anciens hominidés.Excavations at the late Middle Pleistocene cave site of Galeria Pesada in Portuguese Estremadura have uncovered a series of lithic assemblages associated with abundant faunal remains (Excavations 1997-1999). The lithic assemblages are all similar and consist of a combination of a few classic Acheulean tools, a rich series of bifacial tools (foliates, small asymmetric bifaces, Keilmesser, etc.), and a large number of scrapers, often on quartz. These assemblages, unknown to date in the rest of Iberia, are associated with Cervids and Equids, cut marks on bones indicate extensive and intensive carcass modification and consumption by hominids
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