Non-mammalian model systems for studying neuro-immune interactions after spinal cord injury

Mammals exhibit poor recovery after injury to the spinal cord, where the loss of neurons and neuronal connections can be functionally devastating. In contrast, it has long been appreciated that many non-mammalian vertebrate species exhibit significant spontaneous functional recovery after spinal cord injury (SCI). Identifying the biological responses that support an organism\u27s inability or ability to recover function after SCI is an important scientific and medical question. While recent advances have been made in understanding the responses to SCI in mammals, we remain without an effective clinical therapy for SCI. A comparative biological approach to understanding responses to SCI in non-mammalian vertebrates will yield important insights into mechanisms that promote recovery after SCI. Presently, mechanistic studies aimed at elucidating responses, both intrinsic and extrinsic to neurons, that result in different regenerative capacities after SCI across vertebrates are just in their early stages. There are several inhibitory mechanisms proposed to impede recovery from SCI in mammals, including reactive gliosis and scarring, myelin associated proteins, and a suboptimal immune response. One hypothesis to explain the robust regenerative capacity of several non-mammalian vertebrates is a lack of some or all of these inhibitory signals. This review presents the current knowledge of immune responses to SCI in several non-mammalian species that achieve anatomical and functional recovery after SCI. This subject is of growing interest, as studies increasingly show both beneficial and detrimental roles of the immune response following SCI in mammals. A long-term goal of biomedical research in all experimental models of SCI is to understand how to promote functional recovery after SCI in humans. Therefore, understanding immune responses to SCI in non-mammalian vertebrates that achieve functional recovery spontaneously may identify novel strategies to modulate immune responses in less regenerative species and promote recovery after SCI

An advanced finite element model for BiCMOS process oriented ultra-thin wafer deformation

A process-oriented wafer-scale finite element model is developed and validated. The model is used to study the relationship between the in-plane residual stress and the deformation of state-of-the-art 0.13- μ m SiGe BiCMOS fully processed 8-inch wafers. Based on the in-situ wafer bow measurement results, the residual stress values are extracted regarding each deposited material per process step. The extracted material residual stress values are integrated into the in-plane stresses of each back-end redistribution layer by knowing the material densities, greatly reducing the computational effort. An advanced finite element model composed of these integrated redistribution layers is therefore developed by exploiting the first order shear deformation theory. The model is validated using analytical solutions and is used to characterize the wafer thickness-deflection non-linear relationship. As a comparison, 8 fully processed BiCMOS wafers from the same lot are thinned to different thicknesses ranging from 50 μ m to 600 μ m for bow measurement. After taking the gravity-induced deflection and grinding effect into consideration, the wafer bow predicted by the finite element model deviates less than 20% from the measurement results for all the thickness values

BiCMOS Integrated Microfluidic Packaging by Wafer Bonding for Lab-on-Chip Applications

International audienc

BiCMOS Embedded Microfluidic Technology Based on Wafer Bonding Techniques for Biosensor Applications

International audienc