Some effects of simultaneous administration of crude aqueous extracts of Mangifera indica leaves and tetracyline on the liver of adults wistar rats

This study was designed to determine the simultaneous effect of Mangifera indica crude aqueous extract and the therapeutic dose of tetracycline on some hepatic enzymes (ALT and AST) and histology of the liver of adult wistar rats. 25 wistar rats were divided into 5 groups: Group A was untreated and served as control group, group B was treated with only 2mL of mango leaves decoction, group C was treated with only 5.4mg/kg of tetracycline, group D was treated with 1mL of mango leaves decoction and 4.8mg/kg of tetracycline and group E was treated with 3mL of mango leaves decoction and 7.7mg/kg of tetracycline simultaneously. The administration period lasted for only 14 days which was given gavagely and the rats were sacrificed on the 15th day by cervical dislocation. The liver was removed, fixed in 10% formal saline and stained in H and E. The transaminase enzymes (the AST and ALT) were measured to determine possible changes in their hepatic leaves. The result shows that the crude aqueous extract of mango levels has adverse effect on the morphology and some hepatic enzyme (ALT and AST) of the liver (such as enlargement of the central vein, reduction in the size of sinusoids), the therapeutic dose of the tetracycline have no detrimental effect on the morphology and the hepatic enzymes of the liver. In conclusion, the extract of mango leaves decoction has adverse effect on the liver histology and the therapeutic dosage of tetracycline has no adverse effect on the histology of the liver.Keywords: Mango leaves, Tetracycline, Liver histology, Liver enzymes (AST and ALT

Linkage design effect on the reliability of surface-micromachined microengines driving a load

The reliability of microengines is a function of the design of the mechanical linkage used to connect the electrostatic actuator to the drive. The authors have completed a series of reliability stress tests on surface micromachined microengines driving an inertial load. In these experiments, the authors used microengines that had pin mechanisms with guides connecting the drive arms to the electrostatic actuators. Comparing this data to previous results using flexure linkages revealed that the pin linkage design was less reliable. The devices were stressed to failure at eight frequencies, both above and below the measured resonance frequency of the microengine. Significant amounts of wear debris were observed both around the hub and pin joint of the drive gear. Additionally, wear tracks were observed in the area where the moving shuttle rubbed against the guides of the pin linkage. At each frequency, they analyzed the statistical data yielding a lifetime (t{sub 50}) for median cycles to failure and {sigma}, the shape parameter of the distribution. A model was developed to describe the failure data based on fundamental wear mechanisms and forces exhibited in mechanical resonant systems. The comparison to the model will be discussed