392 research outputs found
The flavor transition process in the SSM with the mass insertion approximation
People extend the MSSM with the local gauge group to obtain the
SSM. In the framework of the SSM, we study the flavor
transition process with the mass insertion
approximation (MIA). By the MIA method and some reasonable parameter
assumptions, we can intuitively find the parameters that have obvious effect on
the analytic results of the flavor transition process .
By means of the influences of different sensitive parameters, we can obtain
reasonable results to better fit the experimental data
Micro-tensile Testing of the Lightweight Laminated Structures of Beetle Elytra Cuticle
Quantitative measurements of the mechanical properties of insect cuticle are a useful tool in the development of bio-mimetic materials suitable for industrial products. In this study, a micro-tensile tester was used to investigate the mechanical properties of elytra cuticle of the dung beetle (Copris ochus Motschulsky). Micro tensile testing show that: yield strength (Fs) =17.12±3.55N, Maximum tensile (Fb) =14.74±4.11N, yield strength ( ) =1.4±0.15GPa, tensile strength ( )=1.2±0.21GPa, elastic modulus(E) =14.56±4.20GPa, plastic index(δ) =0.241±0.10. Tensile elongation of the specimens was between 12.1-36.3%. Our results demonstrate that the elytra possess ductile material characteristics. Field emission scanning electron microscopy (FESEM) was used to investigate the detailed structure of the elytra cross section in both the transverse and longitudinal directions. In the transverse direction, the fibers of the deeper layers of the endocuticle are orientated in a constant, rotated angle with neighboring fibers rotated in relation to the each other in the same direction. The fibers in the longitudinal direction show that the epicuticle, exocuticle and endocuticle layers clearly create a parallel hierarchical structure. We believe this is a result of the composite effect of the hierarchical structure. Finally, we developed a laminated model based on the parameters provided by tensile testing, FESEM imaging and nanoindentation measurements, and compared the results of the model to our experimental results. Key words: nanoindentation; micro-tensile testing; coupled analysis; laminated structur
Synaptophysin Expression in Rat Retina Following Acute High Intraocular Pressure
In response to injury, synapse alteration may occur earlier than the changes in the cell body of neurons. Although retinal ganglion cell death and thinning of the inner part of retina were found after acute high intraocular pressure (HIOP), the structural and functional changes of synapses in the retina remain unknown. In the present study, we investigated the protein and mRNA expression of synaptophysin (SYN), an important molecule closely related to synaptic activities, synaptogenesis and synaptic plasticity. In addition, we also studied the ultrastructural changes of the retinal synapses. We found that (1) synaptophysin was upregulated transiently at both protein and mRNA level following HIOP; (2) broadened distribution of synaptophysin protein was present within the outer nuclear layer at the early stage following HIOP; (3) in the outer nuclear layer bouton-like vesicle-containing structures were observed by electron microscopy. This data suggested that, besides degeneration, synapses in rat retina may undergo regenerative events following HIOP
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