Structural design synthesis approach to filamentary composites

Structural design methods for analysis of multilayer or laminated filamentary composite

Minimum weight design of symmetrically stiffened orthotropic cylinders under axial compression

Minimum weight design of symmetrically stiffened orthotropic cylinders under axial compressio

Minimum weight design aspects of stiffened cylinders under compression

Survey on minimum weight design aspects of stiffened cylinders under compressio

Some aspects of ammonia toxicity on the gill pathology of carp (Cyprinus carpio L.) and trout (Salmo gairdneri R.)

The toxic effects of ammonia on the gill structure of common carp, Cvprinus carpio L. and rainbow trout Salmo gairdneri R., were investigated by both light microscopic histological studies, scanning and transmission electron microscopical studies. Experimental procedures adopted included the use of standard dilution water under constant temperature conditions and commonly used buffers to stabilize the pH, while additional experiments were also conducted in non buffered dilution water. The common pathological changes noted for both carp and trout included severe chloride cell proliferation, excessive mucous secretions and an infiltration of large numbers of eosinophilic granular cells into the gill epithelia. Prolonged exposure to high concentrations of ammonia resulted in progressive necrosis of chloride, mucous and eosinophilic granular cells. Apoptotic changes indicative of cell death in the gill epithelium included the appearance of condensed darkened cells, and cells with nuclear changes such as pyknosis and karyorrhexis. Dilation of mitochondria, loss of mitochondrial matrix, and appearance of dark inclusions were particularly noted in the carp gill chloride cells. Damage to the mucous cells consisted of premature occlusion of the mucous vesicles and flocculation of the mucous material within the mucous cells, resulting in progressive vacuolations, necrosis and thus a reduction in the stainable population of mucous cells. However, specific lesion types varied between the carp and trout. Carp gills developed massive hyperplastic and hypertrophic lesions comprising of grossly swollen gill epithelial and infiltration cells under buffered experimental conditions, while such lesions were not only less extensive in non buffered experimental conditions but the tissue changes were dominated by the loosening and sloughing of the gill epithelium. Discrepancies in the histological alterations were however evident as a consequence of the presence of buffers and hence the very validity of the recommendation and use of buffer chemicals in toxicity testing was questioned. In the case of trout no hyperplastic lesions such as those seen in carp were not seen but an increased inter and intra cellular oedema was characteristic. Under normal water hardness conditions trout gills apparently showed no variations due to the presence of different buffers or in the non-buffered water conditions. But under high hardness conditions and in the presence of buffer, the gill, lesions were more extensive and necrotic. The results suggest that while ammonia brings about necrotic changes in the gill tissues of both, carp and trout, the lesions arc more necrotic in carp than in trout. These results also indicate that the indiscriminate use of buffers and variations in the water quality conditions might have been the cause of wide variations in the reported toxicity values of ammonia to fish in addition to the reported differences in pathology in the available published literature. The recent reports of a small number of workers that ammonia per se does not cause any pathology is not supported by the present investigations

General uniqueness and monotone iterative technique for fractional differential equations

AbstractIn this paper, the general existence and uniqueness result is proved which exhibits the idea of comparison principle. This result is also valid for fractional differential equations in a Banach space. The well-known monotone iterative technique is then extended for fractional differential equations which provides computable monotone sequences that converge to the extremal solutions in a sector generated by upper and lower solutions

The Natural Logarithm on Time Scales

We define an appropriate logarithm function on time scales and present its main properties. This gives answer to a question posed by M. Bohner in [J. Difference Equ. Appl. {\bf 11} (2005), no. 15, 1305--1306].Comment: 6 page

The Effect of Indole-3-Acetic Acid (IAA) on the Activity Levels of Dehydrogenases in the Silkgland of Silkworm, Bombyx Mori L

The effect of indole-3-acetic acid (IAA) on the glucose-6-phosphate dehydrogenase (G-6-PDH),lactate dehydrogenase (LDH), glutamate dehydrogenase (GDH), iso-citrate dehydrogenase (ICDH), succinate dehydrogenase (SDH) and malate dehydrogenase (MDH) were studied The stimulation of G-6-PDH activity in the silk gland of experimental larva indicates increased oxidation of glucose resulting in higher levels of NADPH. Increased G-6-PDH activity in the present study suggests this as compensatory mechanism to maintain the structural complexity, functional integrity and metabolic centrality of the cells The activity of LDH, ICDH, MDH and SDH were increased in the silk gland of IAA treated larvae. The increased activity of the dehydrogenases may be attributed to increased turnover of aminoacids and oxidative metabolism in the silk gland. The activity level of GDH was increased in silk gland which indicates the increased oxidation of glutamate