272 research outputs found

    Characterization of As(III) oxidizing Achromobacter sp. strain N2 : effects on arsenic toxicity and translocation in rice

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    Achromobacter sp. strain N2 was isolated from a pyrite-cinder-contaminated soil and presented plant growth promoting traits (ACC deaminase activity, production of indole-3-acetic and jasmonic acids, siderophores secretion, and phosphate solubilization) and arsenic transformation abilities. Achromobacter sp. strain N2 was resistant to different metals and metalloids, including arsenate (100 mM) and arsenite (5 mM). The strain was resistant to ionic stressors (i.e., arsenate and NaCl), whereas bacterial growth was impaired by osmotic stress. Strain N2 was able to oxidize 1.0 mmol L-1 of arsenite to arsenate in 72 h. This evidence was supported by the retrieval of an arsenite oxidase AioA gene highly homologous to arsenite oxidases of Achromobacter and Alcaligenes species. Rice seeds of Oryza sativa (var. Loto) were bio-primed with ACCD-induced and non-induced cells in order to evaluate the effect of inoculation on rice seedlings growth and arsenic uptake. The bacterization with ACCD-induced cells significantly improved seed germination and seedling heights if compared with the seeds inoculated with non-induced cells and non-primed seeds. Enhanced arsenic uptake was evidenced in the presence of ACCD-induced cells, suggesting a role of ACCD activity on the mitigation of the toxicity of arsenic accumulated by the plant. This kind of responses should be taken into account when proposing PGP strains for improving plant growth in arsenic-rich soils

    Steady-state behavior of large water distribution systems: Algebraic multigrid method for the fast solution of the linear step

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    The Newton-based global gradient algorithm (GGA) (also known as the Todini and Pilati method) is a widely used method for computing the steady-state solution of the hydraulic variables within a water distribution system (WDS). The Newton-based computation involves solving a linear system of equations arising from the Jacobian of the WDS equations. This step is the most computationally expensive process within the GGA, particularly for large networks involving up to O(105) variables. An increasingly popular solver for large linear systems of the M-matrix class is the algebraic multigrid (AMG) method, a hierarchical-based method that uses a sequence of smaller dimensional systems to approximate the original system. This paper studies the application of AMG to the steady-state solution of WDSs through its incorporation as the linear solver within the GGA. The form of the Jacobian within the GGA is proved to be an M-matrix (under specific criteria on the pipe resistance functions), and thus able to be solved using AMG. A new interpretation of the Jacobian from the GGA is derived, enabling physically based interpretations of the AMG's automatically created hierarchy. Finally, extensive numerical studies are undertaken where it is seen that AMG outperforms the sparse Cholesky method with node reordering (the solver used in EPANET2), incomplete LU factorization (ILU), and PARDISO, which are standard iterative and direct sparse linear solvers. © 2012 American Society of Civil Engineers.A. C. Zecchin; P. Thum; A. R. Simpson; and C. Tischendor

    Bioprospecção de bactérias isoladas de milho para promoção de crescimento de plantas.

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    Isolados bacterianos associados a raízes de milho identificados por sequenciamento parcial do gene 16S RNAr foram avaliados em testes de promoção de crescimento vegetal. Também foram conduzidos testes in vitro para a capacidade de produção de sideróforos, solubilização de fosfato, produção de AIA, FBN e produção de enzimas líticas. Cinco isolados apresentaram resultados promissores na caracterização enzimática e nos testes de atividade promotora de crescimento e, portanto, poderão ser avaliados in vivo quanto a parâmetros de crescimento vegetal em ensaios em casa de vegetação

    Pliocene-Quaternary mass wasting along the Ionian Calabrian margin, offshore southern Italy

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    The Ionian Calabrian margin, offshore southern Italy, is a tectonically active area, located above a subduction zone dominated by the rollback of the African plate. A variety of mass wasting features are known to occur along the inner continental slope, based on seafloor mapping during the Italian project MaGIC (Marine Geohazards Along the Italian Coasts). New high-resolution geophysical data are available from a wider area following two surveys, in 2014 of the German RV Meteor, which acquired multibeam bathymetry (50 m DTM) and Parasound sub-bottom profiles, and in 2015 of the Italian RV OGS Explora, which acquired Chirp sub-bottom and multichannel seismic reflection profiles. Here we integrate these data with existing geophysical datasets and published exploration wells to map submarine slope failures and mass wasting deposits within the Pliocene-Quaternary succession. The results show that features of mass failures are widespread along the steep (higher than 10\ub0) slopes of the Ionian margin south of Calabria and within the intra-slope basins of the margin east of Calabria. Seafloor features range from small-scale features (hundreds of meters in extent), mainly located on the canyon headwalls and sidewalls, to larger slides ( up to 10 km in extent) on open slopes. Subsurface profiles across open slopes and intra-slope basins provide evidence of repeated failures, particularly in the upper Quaternary. The stratigraphic distribution of failures suggests that widespread mass wasting features occur above an unconformity tentatively dated to the Middle Pleistocene (<1 Ma). This unconformity also provides a lower bound for the onset of canyon formation. We infer that the onset of both mass wasting and canyon formation could be a response to the rapid km-scale differential uplift of Calabria over last 1 Ma, which has driven a seaward tilting of the Ionian Calabrian margin

    The central role of Italy in the spatial spread of USUTU virus in Europe

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    USUTU virus (USUV) is an arbovirus maintained in the environment through a bird-mosquito enzootic cycle. Previous surveillance plans highlighted the endemicity of USUV in North-eastern Italy. In this work, we sequenced 138 new USUV full genomes from mosquito pools (Culex pipiens) and wild birds collected in North-eastern Italy and we investigated the evolutionary processes (phylogenetic analysis, selection pressure and evolutionary time-scale analysis) and spatial spread of USUV strains circulating in the European context and in Italy, with a particular focus on North-eastern Italy. Our results confirmed the circulation of viruses belonging to four different lineages in Italy (EU1, EU2, EU3 and EU4), with the newly sequenced viruses from the North-eastern regions, Veneto and Friuli Venezia Giulia, belonging to the EU2 lineage and clustering into two different sub-lineages, EU2-A and EU2-B. Specific mutations characterize each European lineage and geographic location seem to have shaped their phylogenetic structure. By investigating the spatial spread in Europe, we were able to show that Italy acted mainly as donor of USUV to neighbouring countries. At a national level, we identified two geographical clusters mainly circulating in Northern and North-western Italy, spreading both northward and southward. Our analyses provide important information on the spatial and evolutionary dynamics of USUTU virus that can help to improve surveillance plans and control strategies for this virus of increasing concern for human health

    Remote multiparametric monitoring and management of heart failure patients through cardiac implantable electronic devices

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    In this review we focus on heart failure (HF) which, as known, is associated with a substantial risk of hospitalizations and adverse cardiovascular outcomes, including death. In recent years, systems to monitor cardiac function and patient parameters have been developed with the aim to detect subclinical pathophysiological changes that precede worsening HF. Several patient-specific parameters can be remotely monitored through cardiac implantable electronic devices (CIED) and can be combined in multiparametric scores predicting patients’ risk of worsening HF with good sensitivity and moderate specificity. Early patient management at the time of pre-clinical alerts remotely transmitted by CIEDs to physicians might prevent hospitalizations. However, it is not clear yet which is the best diagnostic pathway for HF patients after a CIED alert, which kind of medications should be changed or escalated, and in which case in-hospital visits or in-hospital admissions are required. Finally, the specific role of healthcare professionals involved in HF patient management under remote monitoring is still matter of definition. We analyzed recent data on multiparametric monitoring of patients with HF through CIEDs. We provided practical insights on how to timely manage CIED alarms with the aim to prevent worsening HF. We also discussed the role of biomarkers and thoracic echo in this context, and potential organizational models including multidisciplinary teams for remote care of HF patients with CIEDs

    Favorable Trend of Implantable Cardioverter-Defibrillator Service Life in a Large Single-Nation Population: Insights From 10-Year Analysis of the Italian Implantable Cardioverter-Defibrillator Registry

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    Background: Implantable cardioverter-defibrillators (ICDs) are widely employed for the prevention of sudden cardiac death. Despite technological improvements, patients often need to undergo generator replacement, which entails the risk of periprocedural complications. Our aim was to estimate the service life of ICDs over a 10-year interval and to assess the main causes of replacement on the basis of data from the National ICD Registry of the Italian Society of Arrhythmology and Cardiac Pacing (AIAC). Methods and Results: The registry includes data from over 400 hospitals in Italy. We included all patients who underwent device replacement from calendar years 2007 to 2016. The median service life of the ICDs and its trend over the years was estimated across the 3 types of devices (single-chamber, dual-chamber, cardiac resynchronization therapy defibrillator) and the indication to implantation. The causes of replacement were also analyzed. We included 29&nbsp;158 records from 27&nbsp;676 patients (80.9% men; mean age at device replacement 65.8±12.0&nbsp;years). The median service life was 57.3 months (interquartile range 27.8&nbsp;months). Over the years, service life showed an increasing trend. The majority of patients underwent elective replacement because of battery end of life, and over the years there was a significant reduction of replacement for recalls, erosion/infections, and cardiac resynchronization therapy upgrading. Conclusions: Our data from a large single-nation population showed that the trend of ICD service life, independently from ICD type, indication, and settings, significantly improved over time. Moreover, there was a striking reduction of interventions for upgrading and infection/erosion. This favorable trend has important clinical, organizational, and financial implications

    An Eye for Possibilities in the Development of Children with Cerebral Palsy: Neurobiology and Neuropsychology in a Cultural-Historical Dynamic Understanding

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    Taking children with Cerebral Palsy (CP) as an example, the article seeks an understanding ofchildren with disabilities that connects neuropsychological theories of neural development withthe situated cognition perspective and the child as an active participant in its social practices. Theearly brain lesion of CP is reconceptualised as a neurobiological constraint that exists in therelations between the neural, cognitive and social levels. Through a multi-method study of twochildren with CP, it is analysed how neurobiological constraints arise, evolve and sometimes areresolved through local matches between the child and its social practices. The result is discussedas support of a developmental science approach that includes processes at the social practice levelalong with knowledge of biological processes

    Phylogenetic Structure and Metabolic Properties of Microbial Communities in Arsenic-Rich Waters of Geothermal Origin

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    Arsenic (As) is a toxic element released in aquatic environments by geogenic processes or anthropic activities. To counteract its toxicity, several microorganisms have developed mechanisms to tolerate and utilize it for respiratory metabolism. However, still little is known about identity and physiological properties of microorganisms exposed to natural high levels of As and the role they play in As transformation and mobilization processes. This work aims to explore the phylogenetic composition and functional properties of aquatic microbial communities in As-rich freshwater environments of geothermal origin and to elucidate the key microbial functional groups that directly or indirectly may influence As-transformations across a natural range of geogenic arsenic contamination. Distinct bacterial communities in terms of composition and metabolisms were found. Members of Proteobacteria, affiliated to Alpha- and Betaproteobacteria were mainly retrieved in groundwaters and surface waters, whereas Gammaproteobacteria were the main component in thermal waters. Most of the OTUs from thermal waters were only distantly related to 16S rRNA gene sequences of known taxa, indicating the occurrence of bacterial biodiversity so far unexplored. Nitrate and sulfate reduction and heterotrophic As(III)-oxidization were found as main metabolic traits of the microbial cultivable fraction in such environments. No growth of autotrophic As(III)-oxidizers, autotrophic and heterotrophic As(V)-reducers, Fe-reducers and oxidizers, Mn-reducers and sulfide oxidizers was observed. The ars genes, involved in As(V) detoxifying reduction, were found in all samples whereas aioA [As(III) oxidase] and arrA genes [As(V) respiratory reductase] were not found. Overall, we found that As detoxification processes prevailed over As metabolic processes, concomitantly with the intriguing occurrence of novel thermophiles able to tolerate high levels of As
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