Presentation 54,55
Presentation 54
Augmentation Of Brain Perfusion And vascular Permeability Through Controlled Stimulation On The Sphenopalatine Ganglion
Prof. David Yarnitsky
Head Department of Neurology, Head Laboratory of Clinical Neurophysiology
BrainsGate, Rambam Medical Center, Technion Faculty of Medicine
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The brain tightly controls its environment, keeping its blood perfusion within a narrow limit, and blocking its vessel walls from permeation of most molecules (via the blood-brain-barrier, BBB). While this control is highly advantageous for maintaining the delicate function of this organ for health reasons, it hinders the ability of the brain to combat diseases, when (i) increased blood supply, or (ii) increased permeation of various beneficial molecules could help. The sphenopalatine ganglion (SPG), an extracranial neural structure innervates most of the brain's vessels, and when electrically stimulated can (i) increase cerebral blood flow, and, (ii) at a different stimulation level, modulate the BBB to increase its permeability. BrainsGate has developed an electrode that can easily be placed adjacent to this ganglion, and by using an external controller it can stimulate the ganglion. Human and animal data shows clear dilatation of cerebral vessels, and in an animal stroke model a significant decrease in stroke volume, with substantial improvement of functional outcome was documented.
A large study on acute ischemic stroke patients is expected to start at mid 2006. Regarding BBB opening, 10 patients with advanced brain tumor were recruited to a study where chemotherapy was administered during SPG stimulation. Initial indications suggest opening of the BBB, with no side effects, in these patients. Controlled stimulation of the SPG is expected to help patients with (i) acute cerebral stroke and cerebral vasospasm by improving blood flow, and by trophic effects of the neurotransmitters secreted by fibers from the SPG. Dementia and traumatic brian injury can also benefit from the latter, (ii) Brain tumors, Alzheimer's disease and various other degenerative and metabolic brain diseases by allowing permeation of various medications through the BBB.
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Presentation 55
Network Simulation in Grid Design, Development and Deployment
Gal Ofel
Shunra Software
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Any organization attempting to take advantage of recent innovations in grid computing must pay close attention to network infrastructure. That's because grid computing depends on a diverse number of network connections to link multiple CPUs in a grid environment - which means that even the most subtle impairments in those connections will have a direct impact on the performance of applications running on the grid.
Shunra's Virtual Enterprise (VE) network simulation technology directly addresses this critical grid implementation challenge by providing full visibility into the impact of all impairments (including distance- and configuration-driven latencies, bandwidth constraints, packet loss, jitter and QoSⅠMPLS classification schemes, etc.) on total application performance. Latencies can be a particularly important factor in grid performance, since transaction delays force servers to keep processing resources "on hold" for longer periods of time and may thus significantly compromise the performance and scalability of complex applications. Shunra VE also simulates other relevant attributes of current or planned grid environments - such as the number and location of CPUs, the number and distribution of end-users, and active application loads. These network conditions can be either captured from an existing network or synthesized based on projected parameters.
The unique accuracy, flexibility and ease-of-use of the network simulation offered by Shunra VE makes it ideal for grid implementers, who are otherwise unable to anticipate the impact of network impairments on application performance. This highly accurate simulation environment can be used across the entire project lifecycle to ensure the viability of the initial implementation, manage change over time, effectively plan expansion, and troubleshoot application performance issues as they arise.
