Respiratory metabolism in Oreochromis mossambicus, Peters under different environmental conditions

Oxygen consumption in Oreochromis mossambicus, Peters (3-60g in weight) was measured under different stress conditions at a constant temperature of 20±1°C. The rate of oxygen consumption was significantly higher (0.170 ml gˉ¹hˉ¹)at a salinity of 30x10ˉ³ compared with that (0.132ml gˉ¹hˉ¹) in freshwater. The oxygen consumption was also found to be affected by changes in pH. Weight specific rate decreased significantly from 0.113 to 0.045 ml gˉ¹hˉ¹ with increasing body weight. A positive correlation was recorded between availability of dissolved oxygen and the rate of oxygen consumption by the fish. While copper sulphate and malachite green inhibited the respiratory metabolism, formaldehyde treatment raised it from 0.088 to 0.118ml gˉ¹hˉ¹.

Failure mechanisms and toughness of Al2O3 ductile-particle toughened ceramics and SiC fibre-ceramic composites

The development of high performance ceramics and ceramic composites often relies on assumptions about their behaviour during loading and at failure. A crucial influence on the mechanical properties of these materials is the degree of sub-critical cracking, which post mortem investigations cannot adequately reveal. Hence a clear picture of the dynamic micromechanisms of cracking is required if applications of fracture and damage mechanics to theoretical models is to be meaningful.

A comparison of different failure assessment methodologies applied to the NESC-1 test

Predictions for a 75x205mm surface semi-elliptic defect in the NESC-1 spinning cylinder test have been made using BS PD 6493:1991, the R6 procedure, non-linear cracked body finite element analysis techniques and the local approach to fracture. All the techniques agree in predicting ductile tearing near the inner surface of the cylinder followed by cleavage initiation. However they differ in the amount of ductile tearing, and the exact location and time of any cleavage event. The amount of ductile tearing decreases with increasing sophistication in the analysis, due to the drop in peak crack driving force and more explicit consideration of constraint effects. The local approach predicts a high probability of cleavage in both HAZ and base material after 190s, while the other predictions suggest that cleavage is unlikely in the HAZ due to constraint loss, but likely in the underlying base material. The timing of this event varies from ∼150s for R6 predictions to ∼250-300s using non-linear cracked body analysis.

Polymorphisms in the C-type lectin genes cluster in chromosome 19 and predisposition to severe acute respiratory syndrome coronavirus (SARS-CoV) infection

Background: Polymorphisms of CLEC4M have been associated with predisposition for infection by the severe acute respiratory syndrome coronavirus (SARS-CoV). DC-SIGNR, a C-type lectin encoded by CLEC4M, is a receptor for the virus. A variable number tandem