220 research outputs found
Peer-to-peer Technologies Applied to Data Warehouses
No full textData mining and user data collection applications, like Facebook and Yahoo, make dealing with huge amounts of data more and more frequent. A solution to cope with this problem is to spread data over multiple network-connected physical devices. Having more devices, though, means increasing system complexity and introducing additional possible points of failure. Moreover, despite the capacity of hard drives as massive storage systems has increased extremely during years, the speed at which data can be accessed has not. In order to address this problem, over the years, distributed file systems, such as NFS and HDFS, have been designed and deployed. Such systems provide access to files stored on multiple hosts connected through a computer network in a transparent way to users. The peer-to-peer network paradigm has been introduced to overcome some limitations of the client-server architecture by adding features, such as scalability, fault-tolerance, and self-organization. In this work, we present a solution that integrates peer-to-peer network support to HDFS in order to realize a flexible, low-cost and, dynamic distributed file system
Hemoadsorption cartridge and coronavirus disease 2019 infections: A case report and brief literature review
No full textThe cytokine storm has been frequently reported to occur in patients with severe coronavirus disease 2019 (COVID-19). Data from the literature suggest that elevated levels of inflammatory mediators, such as interleukin (IL)-6, IL-8, and tumor necrosis factor, indicate a severe course or the fatality of the disease. Several therapeutic options have been employed to treat critically ill patients, including hemoadsorption of inflammatory mediators. We here present a case of severe acute respiratory syndrome caused by COVID-19 and acute renal failure. The patient was admitted to our intensive care unit and treated with mechanical ventilation, renal replacement therapy, and hemoadsorption to reduce the cytokine release syndrome, which plays a fundamental role in the clinical presentation of COVID-19 patients. We also discuss the potential advantages of reducing cytokine plasma levels using a hemoadsorption cartridge
Ricerche su piante officinali nell'Appennino modenese - Piante spontanee - IV - Indagini sull'olio essenziale di Juniperus communis L. (ginepro)
No full textRicerche su piante officinali nell'Appennino modenese - Piante spontanee - IV - Indagini sull'olio essenziale di Juniperus communis L. (ginepro
Analysis of phenolic compounds and radical scavenging activity of Echinacea spp
No full textThe aim of this study was to set up and validate an RP-LC method with DAD-detection to quantify caffeic acid derivatives in various Echinacea spp. Samples were extracted with 80% methanol. The analyses were carried out on a Lichrospher RP-18 column (125 mm x 4 mm i.d., 5 microm), with a mobile phase gradient, which increases the acetonitrile level in a phosphoric acid solution (0.1%). The flow rate was 1.5 ml/min. Detection was set at 330 nm. This method allowed the identification and quantification of caftaric acid, chlorogenic acid, caffeic acid, cynarin, echinacoside and cichoric acid in Echinacea roots and derivatives. The total phenolic content was 10.49 mg/g for E. angustifolia, 17.83 mg/g for E. pallida and 23.23 mg/g for E. purpurea. Among Echinacea commercial herbal medicines, a certain variability in the concentrations of phenolic compounds was observed. The radical scavenging activity of Echinacea methanolic extracts was evaluated in vitro with a spectrophotometric method based on the reduction of an alcoholic 2,2-diphenyl-1-picrylhydrazyl (DPPH*) radical solution at 517 nm in the presence of a hydrogen donating antioxidant. As for pure compounds, echinacoside had the highest capacity to quench DPPH* radicals (EC50 = 6.6 microM), while caftaric acid had the lowest (EC50 = 20.5 microM). The average EC50 values for E. purpurea, E. pallida and E. angustifolia were 134, 167 and 231 microg/ml, respectively. The radical scavenging activity of Echinacea root extracts reflected their phenolic composition. The results indicate that Echinacea roots and derivatives are a good source of natural antioxidants and could be used to prevent free-radical-induced deleterious effects
Melaleuca alternifolia L. ("Tea tree"): indagini analitiche e microbiologiche su oli essenziali e preparati del commercio
No full textMelaleuca alternifolia L. ("Tea tree"): indagini analitiche e microbiologiche su oli essenziali e preparati del commerci
Inter-population variability of secondary metabolites in Hypericum spp. (Hypericaceae) of the Northern Apennines, Italy
No full textHypericum spp. flowers were collected from different sites of Northern Apennines in Italy and were analysed by HPTLC technique to determine their contents in flavonoids (rutin, hyperosid, quercitrin, isoquercitrin and quercetin) and hypericins (pseudohypericin and hypericin). The H. pet bratum and H. richeri composition was evaluated in order to investigate the influence of ecological conditions on secondary metabolites production. The species Studied showed some differences in the amounts of investigated metabolites and high variability was observed in populations gathered in different places. No significant effects of environmental factors on active compound production were observed, except for the rutin content which is in positive correlation with the altitude of the growing site. Interesting informations are also given about the morphology of secretory structures found in Hypericum richeri
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