University of Extremadura

About: University of Extremadura is a education organization based out in Badajoz, Spain. It is known for research contribution in the topics: Population & Hyperspectral imaging. The organization has 7856 authors who have published 18299 publications receiving 396126 citations. The organization is also known as: Universidad de Extremadura.

Arginase activity mediates reversible T cell hyporesponsiveness in human pregnancy

Abstract: Complex regulation of T cell functions during pregnancy is required to ensure maternofetal tolerance. Here we reveal a novel pathway for the temporary suppression of maternal T cell responses in uncomplicated human pregnancies. Our results show that arginase activity is significantly increased in the peripheral blood of pregnant women and remarkably high arginase activities are expressed in term placentae. High enzymatic activity results in high turnover of its substrate L-arginine and concomitant reduction of this amino acid in the microenvironment. Amino acid deprivation is emerging as a regulatory pathway of lymphocyte responses and we assessed the consequences of this enhanced arginase activity on T cell responses. Arginase-mediated L-arginine depletion induces down-regulation of CD3f, the main signalling chain of the TCR, and functional T cell hyporesponsiveness. Importantly, this arginase-mediated T cell suppression was reversible, as inhibition of arginase activity or addition of exogenous L-arginine restored CD3f chain expression and T cell proliferation. Thus, L-arginine metabolism constitutes a novel physiological mechanism contributing to the temporary suppression of the maternal immune response during human pregnancy.

Combustion optimisation of biomass residue pellets for domestic heating with a mural boiler

Abstract: The purpose of this study was to optimise the combustion process of different residues in a 11.6 kW mural boiler for domestic heating. The fuels used were pellets from three biomass residues (tomato, olive stone and cardoon (Cynara cardunculus L.)) and the forest pellet recommended by the boiler manufacturer. Previously, the fuels were characterised by means of the higher heating value, proximate and ultimate analyses. The influence of the residue type, fuel mass flow, draught and residue mixture on the combustion parameters was studied. A TESTO 300 M-I analyzer was used to determine the principal parameters of the combustion process (CO2, CO and O2 contents, fumes temperature, not-burnt gaseous and sensitive heat losses in the fumes, volumetric flow rate and velocity of the fumes, air excess coefficient, efficiency). The behaviour of the three residues is similar to that of the forest pellet. The boiler efficiencies obtained with the maximum fuel mass flow (100%) and minimum draught (0%) were 90%, 90.5%, 89.7% and 91.6% for tomato, forest, olive stone and cardoon pellets, respectively. The optimum residue mixture was tomato (75%) and forest (25%) with a boiler efficiency of 92.4% for a mass flow and draught of 75% and 0%, respectively.