Single Mild Traumatic Brain Injury Induces Persistent Disruption of the Blood-Brain Barrier, Neuroinflammation and Cognitive Decline in Hypertensive Rats

Traumatic brain injury (TBI) induces blood-brain barrier (BBB) disruption, which contributes to secondary injury of brain tissue and development of chronic cognitive decline. However, single mild (m)TBI, the most frequent form of brain trauma disrupts the BBB only transiently. We hypothesized, that co-morbid conditions exacerbate persistent BBB disruption after mTBI leading to long term cognitive dysfunction. Since hypertension is the most important cerebrovascular risk factor in populations prone to mild brain trauma, we induced mTBI in normotensive Wistar and spontaneously hypertensive rats (SHR) and we assessed BBB permeability, extravasation of blood-borne substances, neuroinflammation and cognitive function two weeks after trauma. We found that mTBI induced a significant BBB disruption two weeks after trauma in SHRs but not in normotensive Wistar rats, which was associated with a significant accumulation of fibrin and increased neuronal expression of inflammatory cytokines TNFα, IL-1β and IL-6 in the cortex and hippocampus. SHRs showed impaired learning and memory two weeks after mild TBI, whereas cognitive function of normotensive Wistar rats remained intact. Future studies should establish the mechanisms through which hypertension and mild TBI interact to promote persistent BBB disruption, neuroinflammation and cognitive decline to provide neuroprotection and improve cognitive function in patients with mTBI

Assessment of Properties on AISI430 Ferritic Stainless Steel by Nitriding process

AISI 430 Ferritic Stainless Steel is well known for its good corrosion resistance applicable for high resistance to pitting and stresses. But it lacks in its wear resistance and hardness in order to improve the mechanical properties of AISI 430 Ferritic Stainless-Steel materials Nitriding Heat Treatment is chosen in this project. The samples are taken in the form of cylindrical shapes with diameter 10mm and length 40mm respectively. The specimen is subjected 4 numbers being the highest treated to saturated limit. One specimen is kept as untreated for comparison purpose. Wear test will be carried out under constant speed and with variable load by pin on disk wear testing apparatus. Finally, all the specimens are subjected to various metallographic tests like SEM (Scanning Electron Microscope) and EDAX (X-ray Despresive Analysis) or XRD (X-ray Diffraction) and the results are compared