The mode I toughness of adhesive joints: the results of a European round-robin

Abstract The results of an inter-laboratory round-robin test programme designed to validate a new protocol for determining the mode I adhesive fracture energy, G IC , of structural adhesive joints are presented. The analysis schemes employed by the protocol are described and critically compared in the light of these results. The importance of a number of validity checks on the data analyses are discussed and the accuracy and precision of the test method is determined according to existing International standards. The values of G IC deduced were shown to be independent of the test geometry of the joint (i.e. DCB versus TDCB) but dependent upon the substrate material used. Additional studies have shown that the substrate dependence was due to the cured adhesive in the different joints possessing different values of glass transition temperature

Activation of mTOR signaling in medullary and aggressive papillary thyroid carcinomas

Background. Because mammalian target of rapamycin (mTOR) may be involved in thyroid carcinogenesis, we investigated the expression and activation patterns of mTOR signaling proteins in thyroid carcinoma cells and tumors and their association with tumor histology and aggressiveness. Methods. Tissue specimens from 50 patients with thyroid cancer were analyzed for eIF4E, a critical downstream target of the mTOR pathway, using immunohistochemistry. In addition, fresh-frozen samples from patients, and primary tumor cell cultures were analyzed for expression and activation of mTOR signaling proteins by Western blot. Moreover, pharmacologic studies with rapamycin were performed. Results. High expression of eIF4E was observed in medullary thyroid carcinomas (MTC) and in aggressive variants of papillary thyroid carcinomas (PTC) as compared with conventional PTC and follicular thyroid carcinomas (P < .0001). The level of eIF4E expression also correlated with tumor stage (P = .002). Using Western blot analysis, p-rpS6, p-4EBP1, 4EBP1, and eIF4E were detected at higher levels in aggressive PTC and MTC cells. Treatment of MTC cells with increasing concentrations of rapamycin resulted in significant cell death and in decreased cell growth associated with deactivation of the mTOR pathway. Conclusion. mTOR signaling, which controls protein synthesis through regulation of translation initiation, is activated in aggressive PTC and MTC and represents a promising target for investigational therapies in these patients. (Surgery 2011;150:1258-65.