Prevalence of human T-lymphotropic virus type 1 and 2 among blood donors in Manaus, Amazonas State, Brazil

Introduction: Human T-lymphotropic virus type 1 and 2 (HTLV-1/2) is endemic in Brazil, but few studies have investigated the seroprevalence of HTLV and its subtypes among blood donors in the capital city Manaus, Amazonas State, Brazil. Aim: To estimate the seroprevalence of HTLV-1/2 and to identify circulating subtypes among blood donors in Manaus. Materials and Methods: Blood donors (2001-2003) were screened for HTLV-1/2 antibodies by ELISA. Positive results were confirmed and subtyped by Western blot assays. Prevalence rates were calculated and compared with demographic data. Results: Among the 87,402 individuals screened, 116 (0.13%) were seropositive for HTLV-1/2. A second sample (76/116) was collected and retested by HTLV-1/2 ELISA, of which only 41/76 were positive. Western blot confirmed HTLV infection in 24/41 retested blood donors [HTLV-1 (n=16), HTLV-2 (n=5) and HTLV-untypable (n=3)]. Discussion: HTLV-1 and HTLV-2 are prevalent among blood donors in Manaus. However, additional studies are needed to comprehend the epidemiology of HTLV-1/2 in Amazonas not only to understand the pathophysiology of the disease providing adequate medical assistance, but also to reduce or block virus transmission. © 2017, Instituto de Medicina Tropical de Sao Paulo. All rights reserved

Physical modelling of an array of 25 heaving wave energy converters to quantify variation of response and wave conditions

International audienceExperiments have been performed in the Shallow Water Wave Basin of DHI, in Denmark, on large arrays of up to 25 heaving point absorbers for a range of layout configurations and wave conditions. Float response and modification of the wave field are measured to provide data suitable for the evaluation of array interaction models and environmental scale models. Each wave energy converter unit has a diameter of 0.315 m and power absorption is due to friction of both a power take off system and bearings. Response is measured on all floats and surge force on five floats. Wave gauges are located within and around the array. Wave conditions studied include regular waves and both long- and short-crested irregular waves. A rectilinear arrangement of support structures is employed such that several float configurations can be studied. A summary is presented of the experimental arrangement with particular emphasis on the individual wave energy converters and wave conditions employed. Reasonable agreement is observed between measured response for single floats and power output and float response predicted using a linear time domain model. For an array of 25 floats, up to 16.3% reduction of significant wave height is observed down-wave and 10.8% increase observed up-wave for unidirectional irregular waves due to wave radiation by the heaving WECs. Spectra at different locations within and around the array show the wave field modifications