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Although the deleterious effects of primary blast on gas-filled organs are well accepted, the effect of blast-induced shock waves on the brain is less clear because of factors that complicate the interpretation of clinical and experimental data. Brain cell aggregate cultures are comprised of multiple differentiated brain cell types and were used to examine the effects of underwater blast. Suspensions of these cultures encased in dialysis tubing were exposed to explosive-generated underwater blasts of low (∼300 kPa), medium (∼2,700 kPa), or high (∼14,000 kPa) intensities and harvested at 1-28 days post-exposure. No changes in gross morphology were noted immediately or weeks after blast wave exposure, and no increases in either apoptotic (caspase-3) or necrotic (lactate dehydrogenase) cell death were observed. Changes in neuronal (neurofilament H, acetylcholinesterase, and choline acetyltransferase) and glial (glial fibrillary acidic protein, glutamine synthetase) endpoints did not occur. However, significant time- and pressure-related increases in Akt (protein kinase B) phosphorylation were noted, as well as declines in vascular endothelial growth factor levels, implicating pathways involved in cellular survival mechanisms. The free-floating nature of the aggregates during blast wave exposure, coupled with their highly hydrolyzed dialysis tubing containment, results in minimized boundary effects, thus enabling accurate assessment of brain cell response to a simplified shock-induced stress wave. This work shows that, at its simplest, blast-induced shock waves produce subtle changes in brain tissue. This study has mechanistic implications for the study of primary blast-induced traumatic brain injury and supports the thesis that underwater blast may cause subtle changes in the brains of submerged individuals.

Network function virtualization (NFV) provides flexible and scalable network function for the emerging platform, such as the cloud computing, edge computing, and IoT platforms, while it faces more security challenges, such as tampering with network policies and leaking sensitive processing states, due to running in a shared open environment and lacking the protection of proprietary hardware. Currently, Intel® Software Guard Extensions (SGX) provides a promising way to build a secure and trusted VNF (virtual network function) by isolating VNF or sensitive data into an enclave. However, directly placing multiple VNFs in a single enclave will lose the scalability advantage of NFV. This paper combines SGX and click technology to design the virtual security function architecture based on multiple enclaves. In our design, the sensitive modules of a VNF are put into different enclaves and communicate by local attestation. The system can freely combine these modules according to user requirements, and increase the scalability of the system while protecting its running state security. In addition, we design a new hot-swapping scheme to enable the system to dynamically modify the configuration function at runtime, so that the original VNFs do not need to stop when the function of VNFs is modified. We implement an IDS (intrusion detection system) based on our architecture to verify the feasibility of our system and evaluate its performance. The results show that the overhead introduced by the system architecture is within an acceptable range.

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