http://hdl.handle.net/2440/10692 Mon, 25 Jan 2021 20:52:09 GMT 2021-01-25T20:52:09Z http://hdl.handle.net/2440/128264 Title: Influence of the microstructural and mechanical properties of reinforced graphene in magnesium matrix fabricated by friction stir processing Author: Alam, N.; Iqbal, M.M.; Prakash, C.; Singh, S.; Basak, A. Abstract: The aim of the present researchwork is to find out the influence of uniform dispersion of different volume percentages of graphene nanoparticles into magnesium matrix, fabricated by friction stir processing (FSP). These composites can be used in various applications, particularly in electrical, automobile and aerospace industries due to its lightweight and good electrical and mechanical properties. The friction processed surface of pure magnesium and composites were characterized through X-ray diffraction (XRD). Mechanical properties such as tensile test of the friction stir processed (FSPed) composites were performed in universal testing machine and the specimen was prepared according to standard dimension by wire EDM. The initial properties of the material were compared to the FSPed pure magnesium matrix composites. The role of various volume percentages of reinforcement by FSP resulted in grain refinements as well as improved the mechanical properties of the FSPed composite. Wed, 01 Jan 2020 00:00:00 GMT http://hdl.handle.net/2440/128264 2020-01-01T00:00:00Z http://hdl.handle.net/2440/127607 Title: Optimizing dimensional accuracy of titanium alloy features produced by wire electrical discharge machining Author: Pramanik, A.; Islam, M.N.; Basak, A.K.; Dong, Y.; Littlefair, G.; Prakash, C. Abstract: This study investigates geometrical errors such as cylindricity, circularity and diametral errors of a feature (a hole) produced from wire electrical discharge machining of Ti6Al4V alloy where tension in wire, pulse on time, and flushing pressure are varied. Pareto analysis of variance (ANOVA), Taguchi design of experiment (DoE), and traditional analysis estimate the influence of variables on errors of holes. It was noted that flushing pressure is the most significant factor with individual contributions of 31.02%, 49.5% and 37.84% to circularity, cylindricity, and diametral errors, respectively. The circularity error of holes decreases as the flushing pressure and tension in wire rise, but decreases with the rise of pulse on time. The cylindricity error decreased with the increase of wire tension, flushing pressure and pulse on time. The absolute diametral error reduced as the pulse on time and tension in wire raised, but it raised with the rise of pulse on time. All these trends are associated with the influence of tension in wire on the flexibility of wire, the dependence of heat generation and dissipation on pulse on time, and ability of the flushing pressure to control the cooling, as well as debris removal from the machining zone. Tue, 01 Jan 2019 00:00:00 GMT http://hdl.handle.net/2440/127607 2019-01-01T00:00:00Z http://hdl.handle.net/2440/126351 Title: Mammalian development does not recapitulate suspected key transformations in the evolutionary detachment of the mammalian middle ear Author: Ramírez-Chaves, H.; Wroe, S.; Selwood, L.; Hinds, L.; Leigh, C.; Koyabu, D.; Kardjilov, N.; Weisbecker, V. Abstract: The ectotympanic, malleus and incus of the developing mammalian middle ear (ME) are initially attached to the dentary via Meckel's cartilage, betraying their origins from the primary jaw joint of land vertebrates. This recapitulation has prompted mostly unquantified suggestions that several suspected--but similarly unquantified--key evolutionary transformations leading to the mammalian ME are recapitulated in development, through negative allometry and posterior/medial displacement of ME bones relative to the jaw joint. Here we show, using µCT reconstructions, that neither allometric nor topological change is quantifiable in the pre-detachment ME development of six marsupials and two monotremes. Also, differential ME positioning in the two monotreme species is not recapitulated. This challenges the developmental prerequisites of widely cited evolutionary scenarios of definitive mammalian middle ear (DMME) evolution, highlighting the requirement for further fossil evidence to test these hypotheses. Possible association between rear molar eruption, full ME ossification and ME detachment in marsupials suggests functional divergence between dentary and ME as a trigger for developmental, and possibly also evolutionary, ME detachment. The stable positioning of the dentary and ME supports suggestions that a 'partial mammalian middle ear' as found in many mammaliaforms--probably with a cartilaginous Meckel's cartilage--represents the only developmentally plausible evolutionary DMME precursor. Fri, 01 Jan 2016 00:00:00 GMT http://hdl.handle.net/2440/126351 2016-01-01T00:00:00Z http://hdl.handle.net/2440/125711 Title: ANTI-proliferative transcriptional effects of medroxyprogesterone acetate in Estrogen receptor positive breast cancer cells are predominantly mediated by ThE progesterone receptor. Author: Moore, N.L.; Hanson, A.R.; Ebrahimie, E.; Hickey, T.E.; Tilley, W.D. Abstract: Medroxyprogesterone acetate (MPA) is a first generation progestin that has been in clinical use for various hormonal conditions in women since the 1960s. Although developed as a progesterone receptor (PR) agonist, MPA also has strong binding affinity for other steroid receptors. This promiscuity confounds the mechanistic action of MPA in target cells that express multiple steroid receptors. This study is the first to assess the relative contribution of progesterone, androgen and glucocorticoid receptors in mediating the transcriptional activity of MPA on endogenous targets in breast cancer cells that endogenously express all three receptors at comparable levels. Gene expression profiling in estrogen receptor positive (ER+) ZR-75-1 breast cancer cells demonstrated that although the MPA-regulated transcriptome strongly overlapped with that of Progesterone (PROG), 5α-dihydrotestosterone (DHT) and Dexamethasone (DEX), it clustered most strongly with that of PROG, suggesting that MPA predominantly acts via the progesterone receptor (PR) rather than androgen receptor (AR) or glucocorticoid receptor (GR). Subsequent experiments manipulating levels of these receptors, either through specific culture conditions or with lentiviral shRNAs targeting individual receptors, also revealed a stronger contribution of PR compared to AR and GR on the expression of endogenous target genes that are either commonly regulated by all ligands or specifically regulated only by MPA. A predominant contribution of PR to MPA action in ER + T-47D breast cancer cells was also observed, although a stronger role for AR was evident in T-47D compared to that observed in ZR-75-1 cells. Network analysis of ligand-specific and commonly regulated genes demonstrated that MPA utilises different transcription factors and signalling pathways to inhibit proliferation compared with PROG. This study reaffirms the importance of PR in mediating MPA action in an endogenous breast cancer context where multiple steroid receptors are co-expressed and has potential implications for PR-targeting therapeutic strategies in ER + breast cancer. Tue, 01 Jan 2019 00:00:00 GMT http://hdl.handle.net/2440/125711 2019-01-01T00:00:00Z