1,229 research outputs found
Long Term Aggresome Accumulation Leads to DNA Damage, p53-dependent Cell Cycle Arrest, and Steric Interference in Mitosis.
Juxtanuclear aggresomes form in cells when levels of aggregation-prone proteins exceed the capacity of the proteasome to degrade them. It is widely believed that aggresomes have a protective function, sequestering potentially damaging aggregates until these can be removed by autophagy. However, most in-cell studies have been carried out over a few days at most, and there is little information on the long term effects of aggresomes. To examine these long term effects, we created inducible, single-copy cell lines that expressed aggregation-prone polyglutamine proteins over several months. We present evidence that, as perinuclear aggresomes accumulate, they are associated with abnormal nuclear morphology and DNA double-strand breaks, resulting in cell cycle arrest via the phosphorylated p53 (Ser-15)-dependent pathway. Further analysis reveals that aggresomes can have a detrimental effect on mitosis by steric interference with chromosome alignment, centrosome positioning, and spindle formation. The incidence of apoptosis also increased in aggresome-containing cells. These severe defects developed gradually after juxtanuclear aggresome formation and were not associated with small cytoplasmic aggregates alone. Thus, our findings demonstrate that, in dividing cells, aggresomes are detrimental over the long term, rather than protective. This suggests a novel mechanism for polyglutamine-associated developmental and cell biological abnormalities, particularly those with early onset and non-neuronal pathologies
Parallel Robot Translational Performance Evaluation through Direction-Selective Index (DSI)
Performance indexes usually provide global evaluations of robot performances mixing their translational and/or rotational capabilities. This paper proposes a definition of performance index, called direction-selective index (DSI), which has been specifically developed for parallel manipulators and can provide uncoupled evaluations of robot translational capabilities along relevant directions. The DSI formulation is first presented within a general framework, highlighting its relationship with traditional manipulability definitions, and then applied to a family of parallel manipulators (4-RUU) of industrial interest. The investigation is both numerical and experimental and allows highlighting the two chief advantages of the proposed DSIs over more conventional manipulability indexes: not only are DSIs more accurate in predicting the workspace regions where manipulators can best perform translational movements along specific directions, but also they allow foreseeing satisfactorily the dynamic performance variations within the workspace, though being purely kinematic indexes. The experiments have been carried out on an instrumented 4-RUU commercial robot
Analysis of the effect of geometrical and operational parameters on solute transport in hollow fiber dialyzers with a two-dimensional transport model
High Dynamic Range Images Coding: Embedded and Multiple Description
The aim of this work is to highlight and discuss a new paradigm for representing high-dynamic range (HDR) images that can be used for both its coding and describing its multimedia content. In particular, the new approach defines a new representation domain that, conversely from the classical compressed one, enables to identify and exploit content metadata. Information related to content are used here to control both the encoding and the decoding process and are directly embedded in the compressed data stream. Firstly, thanks to the proposed solution, the content description can be quickly accessed without the need of fully decoding the compressed stream. This fact ensures a significant improvement in the performance of search and retrieval systems, such as for semantic browsing of image databases. Then, other potential benefits can be envisaged especially in the field of management and distribution of multimedia content, because the direct embedding of content metadata preserves the consistency between content stream and content description without the need of other external frameworks, such as MPEG-21. The paradigm proposed here may also be shifted to Multiple description coding, where different representations of the HDR image can be generated accordingly to its content. The advantages provided by the new proposed method are visible at different levels, i.e. when evaluating the redundancy reduction. Moreover, the descriptors extracted from the compressed data stream could be actively used in complex applications, such as fast retrieval of similar images from huge databases
Efecto de la disponibilidad de nitrógeno y agua de los suelos sobre los requerimientos de fósforo del maíz
p.127-131Se estudió el efecto de la disponibilidad de nitrógeno y agua sobre los requerimientos de fósforo del cultivo de maíz, en un experimento realizado en macetas. Se trabajó con 5 suelos en los que se generaron 5 niveles de disponibilidad de P, en tres condiciones: Seco, Húmedo y Húmedo más Nitrógeno. Se evaluó el P disponible por el método de Bray, el P en la solución del suelo, el rendimiento de materia seca del maíz, la concentración de P en las plantas y se estimó la cantidad de P absorbida por difusión y por flujo masal. Se observó una marcada variación de los rendimientos en respuesta a la adición de P y a los distintos niveles de agua y nitrógeno. La menor disponibilidad de N y agua redujo los rendimientos potenciales entre un 15 y un 50 por ciento. La eficiencia en el uso de los recursos analizados fue superior cuando éstos se encontraron cerca del óptimo. Una expresión relativa del rendimiento permitió una mejor interpretación de los resultados. Los niveles críticos de P Bray, así como las dosis de P requeridas no variaron ante las distintas condiciones de disponibilidad de agua y nitrógeno. La interpretación del análisis de suelo, así como las dosis de recomendación fueron independientes del nivel de rendimiento potencial. La mayor disponibilidad de agua y N incrementó las cantidades de P absorbidas por las plantas, facilitando el flujo difusivo
Perspectives and recent advances in super-resolution spectroscopy: Stochastic and disordered-based approaches
Spectroscopic applications are characterized by the constant effort to combine high spectral resolution with large bandwidth. A trade-off typically exists between these two aspects, but the recent development of super-resolved spectroscopy techniques is bringing new opportunities into this field. This is particularly relevant for all applications where compact and cost-effective instruments are needed such as in sensing, quality control, environmental monitoring, or biometric authentication, to name a few. These unconventional approaches exploit several strategies for spectral investigation, taking advantage of concepts such as sparse sampling, artificial intelligence, or post-processing reconstruction algorithms. In this Perspective, we discuss the main strengths and weaknesses of these methods, tracing promising future directions for their further development and widespread adoption. Published under an exclusive license by AIP Publishing
The contribution of hyperspectral remote sensing to identify vegetation characteristics necessary to assess the fate of Persistent Organic Pollutants (POPs) in the environment
Contenidos de fósforo total en suelos con características vérticas de la Provincia de Entre Ríos
p.53-58En Entre Ríos, los suelos con características vérticas ocupan el 69 por ciento del total de la superficie provincial, sin contar el D elta del río Paraná (Proyecto PN U D-FA O -INTA, 1980), generalmente estos suelos son deficientes en fósforo. El objetivo de este trabajo fue evaluar el contenido de fósforo total y su distribución en las fracciones orgánicas e inorgánicas en perfiles de suelos con características vérticas de Entre Ríos. Se tomaron muestras de suelo provenientes de cuatro Vertisoles, tres Alfisoles y un Molisol con características vérticas. En superficie los contenidos de fósforo total (Pt) de los suelos de los tres ordenes estudiados fueron de 200 a 300 mg kg. Del P total superficial de estos suelos predomina la fracción de P orgánico (Po) en relación a las formas inorgánicas (Pi). La distribución del P orgánico total en el perfil sigue un patrón general de disminución con el aumento de la profundidad, mientras que el Pi tiene una tendencia opuesta. Los horizontes C mostraron valores de P inorgánico de 150 a 200 mg de P kg `1 de suelo, reduciéndose aproximadamente a la mitad en los horizontes superficiales. Como resultado de este estudio, se puede concluir que los suelos del centro norte de la provincia de Entre Ríos presentan valores bajos de Pt. En estos suelos son im portantes las proporciones de Po en superficie, las cuales oscilan entre el 60 por ciento el 70 por ciento del Pt
The contribution of hyperspectral remote sensing to identify vegetation characteristics necessary to assess the fate of Persistent Organic Pollutants (POPs) in the environment
During recent years hyperspectral remote sensing data were successfully used to characterise the state and properties
of vegetation. The information on vegetation cover and status is useful for a range of environmental modelling
studies. Recent works devoted to the understanding of the fate of Persistent Organic Pollutants (POPs) in the environment
showed that forests and vegetation in general act as a «sponge» for chemicals present in air and the intensity
of this «capture» effect depends on some vegetation parameters such as surface area, leaf composition, turnover
etc. In the framework of the DARFEM experiment conducted in late June 2001, different airborne hyperspectral
images were acquired and analysed to derive some vegetation parameters of relevance for multimedia models, such
as the spatial distribution of plant species and their relative foliage biomass. The study area, south west of Milan,
encompasses a range of land cover types typical of Northern Italy, including intensive poplar plantations and natural
broad-leaf forest. An intensive field campaign was accomplished during the aerial survey to collect vegetation
parameters and radiometric measurements. Results obtained from the analysis of hyperspectral images, map of vegetation
species, Leaf Area Index (LAI) and foliage biomass are presented and discussed
Diabetic striatopathy: an updated overview of current knowledge and future perspectives
Purpose: Diabetic striatopathy (DS) is a rare complication of poorly controlled diabetes mellitus (DM), characterized by hyperglycemia associated with chorea/ballism and characteristic reversible basal ganglia abnormalities on computed tomography (CT) and/or magnetic resonance imaging (MRI). We propose a narrative review of the literature on this topic, currently unknown to most, and about which physicians should be aware. We intend to summarize, critically review, and take to mean the evidence on this disorder, describing its typical features. Methods: We searched Pubmed for English-language sources using the following keywords in the title and the abstract: diabetic striatopathy, hyperglycemic non-ketotic hemichorea/hemiballism, chorea/hemichorea associated with non-ketotic hyperglycemia, diabetic hemiballism/hemichorea, chorea, hyperglycemia, and basal ganglia syndrome. We collected scientific articles, including case reports, reviews, systematic reviews, and meta-analyses from the years 1975 to 2023. We eliminated duplicate, non-English language or non-related articles. Results: Older Asian women are more frequently affected. Suddenly or insidiously hemichorea/hemiballism, mainly in the limbs, and high blood glucose with elevated HbA1c in the absence of ketone bodies have been observed. Furthermore, CT striatal hyperdensity and T1-weighted MRI hyperintensity have been observed. DS is often a treatable disease following proper hydration and insulin administration. Histopathological findings are variable, and no comprehensive hypothesis explains the atypical cases reported. Conclusion: DS is a rare neurological manifestation of DM. If adequately treated, although treatment guidelines are lacking, the prognosis is good and life-threatening complications may occur occasionally. During chorea/hemiballism, we recommend blood glucose and HbA1c evaluation. Further studies are needed to understand the pathogenesis
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