96 research outputs found

    Phylogenetic Diversity and Genotypical Complexity of H9N2 Influenza A Viruses Revealed by Genomic Sequence Analysis

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    H9N2 influenza A viruses have become established worldwide in terrestrial poultry and wild birds, and are occasionally transmitted to mammals including humans and pigs. To comprehensively elucidate the genetic and evolutionary characteristics of H9N2 influenza viruses, we performed a large-scale sequence analysis of 571 viral genomes from the NCBI Influenza Virus Resource Database, representing the spectrum of H9N2 influenza viruses isolated from 1966 to 2009. Our study provides a panoramic framework for better understanding the genesis and evolution of H9N2 influenza viruses, and for describing the history of H9N2 viruses circulating in diverse hosts. Panorama phylogenetic analysis of the eight viral gene segments revealed the complexity and diversity of H9N2 influenza viruses. The 571 H9N2 viral genomes were classified into 74 separate lineages, which had marked host and geographical differences in phylogeny. Panorama genotypical analysis also revealed that H9N2 viruses include at least 98 genotypes, which were further divided according to their HA lineages into seven series (A–G). Phylogenetic analysis of the internal genes showed that H9N2 viruses are closely related to H3, H4, H5, H7, H10, and H14 subtype influenza viruses. Our results indicate that H9N2 viruses have undergone extensive reassortments to generate multiple reassortants and genotypes, suggesting that the continued circulation of multiple genotypical H9N2 viruses throughout the world in diverse hosts has the potential to cause future influenza outbreaks in poultry and epidemics in humans. We propose a nomenclature system for identifying and unifying all lineages and genotypes of H9N2 influenza viruses in order to facilitate international communication on the evolution, ecology and epidemiology of H9N2 influenza viruses

    Protocol for a prospective collaborative systematic review and meta-analysis of individual patient data from randomised controlled trials of vasoactive drugs in acute stroke: the Blood pressure in Acute Stroke Collaboration, stage-3 (BASC-3)

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    Rationale Despite several large clinical trials assessing blood pressure lowering in acute stroke, equipoise remains, particularly for ischaemic stroke. The ‘Blood pressure in Acute Stroke Collaboration’ (BASC) commenced in the mid 1990s focusing on systematic reviews and meta-analysis of blood pressure lowering in acute stroke. From the start, BASC planned to assess safety and efficacy of blood pressure lowering in acute stroke using individual patient data. Aims To determine the optimal management of blood pressure in patients with acute stroke, encompassing both intracerebral haemorrhage and ischaemic stroke. Secondary aims are to assess which clinical and therapeutic factors may alter the optimal management of high blood pressure in patients with acute stroke and to assess the effect of vasoactive treatments on haemodynamic variables. Methods and design Individual patient data from randomised controlled trials of blood pressure management in participants with ischaemic stroke and/or intracerebral haemorrhage enrolled during the ultra-acute (pre-hospital), hyper-acute (<6 hours), acute (<48 hours) and sub-acute (<168 hours) phases of stroke. Study outcomes The primary effect variable will be functional outcome defined by the ordinal distribution of the modified Rankin Scale; analyses will also be carried out in prespecified subgroups to assess the modifying effects of stroke-related and pre-stroke patient characteristics. Key secondary variables will include clinical, haemodynamic and neuroradiological variables; safety variables will comprise death and serious adverse events. Discussion Study questions will be addressed in stages, according to the protocol, before integrating these into a final overreaching analysis. We invite eligible trials to join the collaboration

    Refrigeration system optimization for drinking water production through atmospheric air dehumidification

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    none4noDrinking water availability is one of the emerging challenges of the twenty-first century. Different technologies are investigated as possible sources of water for the arid regions. Atmospheric water vapor processing is a developing approach whose aim is to cool air to condensate the water present in the atmospheric moisture. Air dehumidification allows obtaining pure drinking water for geographical regions far from sea, rivers, and lakes. This chapter presents the optimization of a refrigeration system for drinking water production through atmospheric air dehumidification. The system uses a fan to force the air through a heat exchanger, in which it is cooled. The water vapor condensates on the cooled heat exchanger surfaces and it is collected by gravity in a tank. The system’s aim is to condensate the maximum water quantity achievable for every atmospheric air condition, represented by temperature, humidity, and pressure. Thus, a mathematical model is defined to determine the optimal atmospheric air flow that maximizes the condensed water production for every atmospheric air condition. Furthermore, to consider the atmospheric condition hourly profiles of the refrigeration system installation site, three air flow control strategies are proposed: hourly, monthly, and yearly. An experimental campaign is set up to validate the model. Experimental test results show that it accurately predicts the drinking water production (gap between -5.6 and +4.1 %). Finally, the case study of a refrigeration system installed in Dubai, United Arab Emirates, is presented to assess and compare the proposed three air flow control strategies.noneBortolini M.; Gamberi M.;Graziani, A.; Pilati F.Bortolini M.; Gamberi M.;Graziani, A.; Pilati F
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