722 research outputs found

    Conceptual Design of a Small Hybrid Unmanned Aircraft System

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    UAS (Unmanned Aircraft System) technologies are today extremely required in various fields of interest, from military to civil (search and rescue, environmental surveillance and monitoring, and entertainment). Besides safety and legislative issues, the main obstacle to civilian applications of UAS systems is the short time of flight (endurance), which depends on the equipped power system (battery pack) and the flight mission (low/high speed or altitude). Long flight duration is fundamental, especially with tasks that require hovering capability (e.g., river flow monitoring, earthquakes, devastated areas, city traffic monitoring, and archeological sites inspection). This work presents the conceptual design of a Hybrid Unmanned Aircraft System (HUAS), merging a commercial off-the-shelf quadrotor and a balloon in order to obtain a good compromise between endurance and weight. The mathematical models for weights estimation and balloon static performance analysis are presented, together with experimental results in different testing scenarios and complex environments, which show 50% improvement of the flight duration

    De novo mitochondrial DNA alteration in child with complex neurilogical compromission.

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    neuromuscular human diseases have been associated with mitochondrial DNA (mtDNA) variations, causing defects of oxidative phosphorylation. These dysfunctions affect preferentially tissues with high energy demands and give arise to several degenerative disorders such as optic neuropathy, cerebellar ataxia, movement disorders, dementia, muscle weakness and deafness. The extremely heterogeneous clinical phenotype is due to the involved tissue, to specific mtDNA mutations and their heteroplasmic level, but also to nuclear DNA alterations, environmental and epigenetic factors. In this study we investigated a child affected by a complex neurological disease whose clinical features were suggestive of a mitochondrial involvement. Methods: mtDNA from proband, her healthy relatives (grandmother, mother and two sisters) and 80 controls were collected and studied by sequencing. The enzymatic activity of specific respiratory chain complex was tested on lymphocytes by spectrophotometric assay. Bioinformatic analysis was performed to predict the pathogenicity of the detected variants. Results: In all subjects we detected 11 known polymorphisms, whereas 1 novel heteroplasmic variant in complex I [ND5:12514G>A (E60K)] was present only in the proband and in her grandmother and absent in controls. The bioinformatics predicted the novel variant to be deleterious. Further, spectrophotometric assay of complex I activity was lower both in the proband and in her relatives than in the controls. Conclusions: We report a novel mtDNA variant detected in a patient affected by a complex neurological disease. The reduction of complex I respiratory chain activity associated to this variant suggests it could exert a pathogenic role in the disease

    Carbon balance and energy fluxes of a Mediterranean crop

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    This paper is based on the analysis of a long-term mass (carbon dioxide, water vapour) and energy (solar radiation) balance monitoring programme carried out during years 2010 and 2012 in an irrigated orange orchard in Sicily, using the Eddy Covariance (EC) method. Orange (Citrus sinensis L.) is one of the main fruit crops worldwide and its evergreen orchard may have a great potential for carbon sequestration, but few data are currently available. In the study, the role of the orchard system in sequestering atmospheric CO2 was analyzed, thus contributing to assess the carbon balance of the specie in the specific environment.Vertical energy fluxes of net radiation, soil heat, sensible heat and latent heat fluxes were measured at orchard scale by EC. Evapotranspiration (ET) values were compared with upscaled transpiration data determined by the sap flow heat pulse technique, evidencing the degree of correspondence between instantaneous transpirational flux at tree level and the micrometeorological measurement of ET at orchard level

    Mitochondrial Oxidative Stress due to Complex I Dysfunction Promotes Fibroblast Activation and Melanoma Cell Invasiveness

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    Increased ROS (cellular reactive oxygen species) are characteristic of both fibrosis and tumour development. ROS induce the trans-differentiation to myofibroblasts, the activated form of fibroblasts able to promote cancer progression. Here, we report the role of ROS produced in response to dysfunctions of mitochondrial complex I, in fibroblast activation and in tumour progression. We studied human fibroblasts with mitochondrial dysfunctions of complex I, leading to hyperproduction of ROS. We demonstrated that ROS level produced by the mutated fibroblasts correlates with their activation. The increase of ROS in these cells provides a greater ability to remodel the extracellular matrix leading to an increased motility and invasiveness. Furthermore, we evidentiated that in hypoxic conditions these fibroblasts cause HIF-1α stabilization and promote a proinvasive phenotype of human melanoma cells through secretion of cytokines. These data suggest a possible role of deregulated mitochondrial ROS production in fibrosis evolution as well as in cancer progression and invasion

    Sewage Sludge Gasification in a Fluidized Bed: Experimental Investigation and Modeling

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    Fluidized bed gasification is a promising process technology to manage the growing amount of sewage sludge (SS) requiring disposal. Two samples of SS, produced in different seasons of the year by a municipal wastewater treatment plant, were subjected to gasification at 850 °C in a bench-scale fluidized bed reactor using, as a gasification agent, a nitrogen/air mixture at different values of oxygen/fuel equivalence ratio (ER = 0.1–0.2). The starting materials and the output streams (syngas, tar, and solid residues) were thoroughly characterized. The fate of specific SS constituents and the characteristics of bottom ashes were addressed, so contributing to the problem of a proper SS management approach in the context of the circular economy. Computer-aided simulations were also performed, which allowed us to predict the composition of the syngas from SS gasification under operating conditions different from those experimentally investigated (i.e., reactor temperature and ER)

    Respiratory chain complex I, a main regulatory target of the cAMP/PKA pathway is defective in different human diseases.

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    In mammals, complex I (NADH-ubiquinone oxidoreductase) of the mitochondrial respiratory chain has 31 supernumerary subunits in addition to the 14 conserved from prokaryotes to humans. Multiplicity of structural protein components, as well as of biogenesis factors, makes complex I a sensible pace-maker of mitochondrial respiration. The work reviewed here shows that the cAMP/PKA pathway regulates the biogenesis, assembly and catalytic activity of complex I and mitochondrial oxygen superoxide production. The structural, functional and regulatory complexity of complex I, renders it particularly vulnerable to genetic and sporadic pathological factors. Complex I dysfunction has, indeed, been found, to be associated with several human diseases. Knowledge of the pathogenetic mechanisms of these diseases can help to develop new therapeutic strategies. (C) 2011 Federation of European Biochemical Societies. Published by Elsevier B. V. All rights reserved

    The role of the emergency department in the management of acute heart failure: an international perspective on education and research

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    Emergency departments are a major entry point for the initial management of acute heart failure (AHF) patients throughout the world. The initial diagnosis, management and disposition - the decision to admit or discharge - of AHF patients in the emergency department has significant downstream implications. Misdiagnosis, under or overtreatment, or inappropriate admission may place patients at increased risk for adverse events, and add costs to the healthcare system. Despite the critical importance of initial management, data are sparse regarding the impact of early AHF treatment delivered in the emergency department compared to inpatient or chronic heart failure management. Unfortunately, outcomes remain poor, with nearly a third of patients dying or re-hospitalised within 3 months post-discharge. In the absence of robust research evidence, consensus is an important source of guidance for AHF care. Thus, we convened an international group of practising emergency physicians, cardiologists and advanced practice nurses with the following goals to improve outcomes for AHF patients who present to the emergency department or other acute care setting through: (a) a better understanding of the pathophysiology, presentation and management of the initial phase of AHF care; (b) improving initial management by addressing knowledge gaps between best practices and current practice through education and research; and (c) to establish a framework for future emergency department-based international education and research

    Factors influencing choice of chemotherapy in metastatic colorectal cancer (mCRC)

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    Management of metastatic colorectal cancer requires a multimodal approach and must be performed by an experienced, multidisciplinary expert team. The optimal choice of the individual treatment modality, according to disease localization and extent, tumor biology, and patient clinical characteristics, will be one that can maintain quality of life and long-term survival, and even cure selected patients. This review is an overview of the different therapeutic approaches available in metastatic colorectal cancer, for the purpose of defining personalized therapeutic algorithms according to tumor biology and patient clinical features

    cAMP-dependent protein kinase regulates post-translational processing and expression of complex I subunits in mammalian cells

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    AbstractWork is presented on the role of cAMP-dependent protein phosphorylation in post-translational processing and biosynthesis of complex I subunits in mammalian cell cultures. PKA-mediated phosphorylation of the NDUFS4 subunit of complex I promotes in cell cultures in vivo import/maturation in mitochondria of the precursor of this protein. The import promotion appears to be associated with the observed cAMP-dependent stimulation of the catalytic activity of complex I. These effects of PKA are counteracted by activation of protein phosphatase(s). PKA and the transcription factor CREB play a critical role in the biosynthesis of complex I subunits. CREB phosphorylation, by PKA and/or CaMKs, activates at nuclear and mitochondrial level a transcriptional regulatory cascade which promotes the concerted expression of nuclear and mitochondrial encoded subunits of complex I and other respiratory chain proteins
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