The colonisation of non-sterile wheat straw by fungi

DUE TO COPYRIGHT RESTRICTIONS ONLY AVAILABLE FOR CONSULTATION AT ASTON UNIVERSITY LIBRARY AND INFORMATION SERVICES WITH PRIOR ARRANGEMENT

A study of the calcium-induced morphological transistions of human erythrocytes

An examination was made of the morphological transitions induced in human erythrocytes by the elevation of cytosolic calcium, and of the biochemical mechanisms responsible. The loss of the discocyte morphology and the sequential progression of cells through the echinocyte stages 1, 2, 3 and sphereo-echinocyte was found to occur in both a calcium concentration- and a time-dependent manner. SDS-PAGE analysis of cytoskeletal proteins prepared from intact cells loaded with 150uM or 1mM calcium revealed the partial proteolytic loss of proteins 2.1, 2.2 and 4.1. The rate of proteolysis was not paralleled by that of echinocytosis, making a causative relationship unlikely. Cytoskeletal integrity did appear to influence shape reversal from the echinocyte to the discocyte morphology after removal of the calcium and ionophore A23187. The loss of 80% protein 4.1, 40% 2.1 and 30% 2.2 was associated with, although not necessarily the sole cause, of irreversible sphereo-echinocytosis. Pre-treatment of cells with wheat germ agglutinin preserved the discocyte morphology despite continued cytoskeletal proteolysis during calcium-loading. All observations were made on cells incubated either in the presence or absence of glycolytic substrates, effectively altering cell metabolic status. This influenced the rate of progression of cells through the echinocyte stages, the rate of proteolysis of cytoskeletal proteins, and the extent and kinetics of shape reversal from cells transformed to the sphereo-echinocyte morphology. The stage 1 to discocyte transition was the rate limiting step of this shape recovery. In contrast the rate of loss of the discocyte morphology was independent of cell metabolic status during exposure to calcium, as was the extent of restoration of the discocyte morphology from cells transformed to stage 1 echinocytes. An hypothesis is presented that echinocytosis is a discontinuous process with discrete steps initiated by different biochemical mechanisms varying in their dependence on metabolic energy.

Sequential pyrolysis and catalytic low temperature reforming of wheat straw

Aim of the work is the implementation of a low temperature reforming (LT reforming) unit downstream the Haloclean pyrolyser in order to enhance the heating value of the pyrolysis gas. Outside the focus of this work was to gain a synthesis gas quality for further use. Temperatures between 400 °C and 500 °C were applied. A commercial pre-reforming catalyst on a nickel basis from Südchemie was chosen for LT reforming. As biogenic feedstock wheat straw has been used. Pyrolysis of wheat straw at 450 °C by means of Haloclean pyrolysis leads to 28% of char, 50% of condensate and 22% of gas. The condensate separates in a water phase and an organic phase. The organic phase is liquid, but contains viscous compounds. These compounds could underlay aging and could lead to solid tars which can cause post processing problems. Therefore, the implementation of a catalytic reformer is not only of interest from an energetic point of view, it is generally interesting for tar conversion purposes after pyrolysis applications. By using a fixed bed reforming unit at 450–490 °C and space velocities about 3000 l/h the pyrolysis gas volume flow could be increased to about 58%. This corresponds to a decrease of the yields of condensates by means of catalysis up to 17%, the yield of char remains unchanged, since pyrolysis conditions are the same. The heating value in the pyrolysis gas could be increased by the factor of 1.64. Hydrogen concentrations up to 14% could be realised.