Gibberellin A 3 (GA 3 ) is a plant growth regulator used in many countries, including Egypt, to accelerate the growth of fruits and vegetables. The present work was conducted to investigate the histopathological and histochemical effects of GA 3 on the liver of albino rats. Administration of GA 3 by gavage at a dose level of 24 p.p.m. in 0.2 ml saline, 3 times a week for 3 weeks induced many histopathological changes in the liver such as cytoplasmic vacuolization of the hepatocytes with pyknotic nuclei, blood vessel congestion and inflammatory leucocytic infiltrations. Histochemical observations revealed marked reduction in total carbohydrates and total protein contents in the hepatocytes. These changes proved to be time dependent. Moreover, the level of the enzymes GOT, GPT and alkaline phosphatase in serum were significantly decreased especially after the third week. In conclusion, the present study showed that GA 3 affected the structure and function of the rat liver.

Gas-atomised powders of Al-Fe-(V, Si) alloys exhibited microstructures consisting of cells and/or some forms of icosahedral phase. The forms of icosahedral phase include irregular shaped aggregates of ultrafine spherical micro-quasicrystalline (MI) particles in α−aluminium phase matrix, ultrafine MI particles in intercellular regions, and globular clusters of randomly oriented MI particles (in medium to coarse size AlFe-V alloy powders) or globular particles of single icosahedral phase (in medium to coarse size Al-Fe-V-Si alloy powders). It has been proposed that solidification behavior of the Al-Fe-(V, Si) alloy powders would be attributed to a competition between growth of α−aluminium phase fronts and freely nucleated icosahedral particles. Interactions between the solidification fronts and dispersed particles, influenced by solidification rates, would control microstructural morphology.

Gas-atomised powders of Al-Fe-(V, Si) alloys exhibited microstructures consisting of several forms of icosahedral phase distributed in either supersaturated solid solution of α-Al matrix, or in intercellular/ dendritic regions depending on powder particle size. During processing of the powders by hot extrusion, the icosahedral phase particles transformed to more stable phase particles. Microstructures of extrudates produced from fine Al-Fe-V powder particles showed homogeneous precipitation of ultrafine needle-like particles in grains and at grain boundaries. This type of microstructure yielded high compressive strengths at room and elevated temperatures. In microstructures of extrudates produced from coarse Al-Fe-V powder particles, ultrafine needle-like particles were observed to coexist with globular particles. Because of large-size globular particles, low compressive strengths at room and elevated temperatures of the extrudates produced from coarse Al-Fe-V powder particles were obtained. The extrudates produced from fine Al-Fe-V-Si powder particles showed microstructures with homogeneous precipitation of spherical-like particles. In contrast, the extrudates produced from coarse Al-Fe-V-Si powder particles resulted in inhomogeneous microstructures, which were attributed to banded structures or donut-shaped aggregates of spherical-like particles. Because of inhomogeneous microstructures, low compressive strengths of the extrudates at room and elevated temperatures were obtained.