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Bisphenol A (BPA) is an endocrine disruptor with a weak estrogenic effect used in industry as a component of food cans. We aimed to study the toxic effects of BPA on mRNA expression of steroidogenic genes and testicular structure in mature male rats. Animals were divided into 3 groups: vehicle control rats as first group, while second group received 10 µg/kg BW and third group received BPA 15 µg/kg BW orally every alternate day for a period of 105 successive days. Serum testosterone level, mRNA expression of genes related to steroid synthesis, histopathological examination, spermatogenesis index and number of Leydig cells were evaluated in this study. Lower serum hormone levels were observed in both BPA-treated groups as compared to the control group. The gene expression patterns of steroidogenic acute regulatory protein (StAR), cytochrome P450 17a(CYP17a) and 3β-Hydroxysteroid dehydrogenase (3β-HSD) were significantly down-regulated in BPA-treated rats compared to control group. Meanwhile, the expression of aromatase (CYP19) and lutinizing hormone receptor (LHR) was significantly up-regulated. Histopathological lesions were observed in the testes and epididymis of BPA-treated rats. Spermatogenesis index and the number of Leydig cells were significantly decreased in BPA-treated groups compared with the control group. This study highlights negative effect of BPA on steroidogenic genes and testicular structure in male rats.
In this work, Taguchi design (orthogonal array, OA9) was used for the adhesion investigation of an epoxy insulator to a double base (DB) propellant grain. In this manner three epoxy resins based on diglycidylether bisphenol A (DGEBA) and three polyamine curing agents with an active diluent based on DGEBA were used. Therefore, the effects of resin type, curing agent type with its amount and diluent quantity as main factors were investigated on the single lap shear strength (adhesion strength) and then the results were quantitatively evaluated by the analysis of variance (ANOVA). The data given of ANOVA predicted that the best adhesion strength of 15.584 ± 1.606 MPa was obtained for the optimum conditions of MANA POX-102 as epoxy resin, H-37 as curing agent with 57 phr, ERYSYS GE-30 as diluent with 5 phr. In comparison, practical result of adhesion strength obtained for the optimum conditions was 15.4 ± 0.2 MPa. Also the Pull-off test results on the surface of the DB propellant showed that the maximum adhesion strength (related to the optimal conditions) is 2.64 ± 0.2 MPa.