. Contribution of individual spikes in burst-induced long-term synaptic modification. J Neurophysiol 95: 1620 -1629, 2006. First published November 30, 2005 doi:10.1152/jn.00910.2005. Longterm synaptic modification depends on the relative timing of individual pre-and postsynaptic spikes, but the rules governing the effects of multispike bursts remain to be fully understood. In particular, some studies suggest that the spike timing dependence of synaptic modification breaks down with high-frequency bursts. In this study, we characterized the effects of pre-and postsynaptic bursts on long-term modification of layer 2/3 synapses in visual cortical slices from young rats. We found that, while pairing-induced synaptic modification depends on the burst frequency, this dependence can be explained in terms of the timing of individual pre-and postsynaptic spikes. Later spikes in each burst are less effective in synaptic modification, but spike efficacy is regulated differently in pre-and postsynaptic bursts. Presynaptically, spike efficacy is progressively weakened, in parallel with short-term synaptic depression. Postsynaptically, spike efficacy is suppressed to a lesser extent, and it depends on postsynaptic potassium channel activation. Such timing-dependent interaction among multiple spikes can account for synaptic modifications induced by a variety of spike trains, including the frequency-dependent transition from depression to potentiation induced by a postsynaptic burst preceding a presynaptic burst.

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Traumatic brain injury, often referred to as the "silent epidemic," is a nondegenerative, non-congenital insult to the brain due to a blow or penetrating object that disrupts the function of the brain leading to permanent or temporary impairment of cognition, physical and psychosocial functions. Traumatic brain injury usually has poor prognosis for long-term treatment and is a major cause of mortality and morbidity worldwide; approximately 10 million deaths and/or hospitalizations annually are directly related to traumatic brain injury. Traumatic brain injury involves primary and secondary insults. Primary injury occurs during the initial insult, and results from direct or indirect force applied to the physical structures of the brain. Secondary injury is characterized by longer-term degeneration of neurons, glial cells, and vascular tissues due to activation of several proteases, glutamate and pro-inflammatory cytokine secretion. In addition, there is growing evidence that the blood-brain barrier is involved in the course of traumatic brain injury pathophysiology and has detrimental effects on the overall pathology of brain trauma, as will be discussed in this work.

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In the domain of content delivery over Internet, each of the Client/Server and P2P communication modes has its pros and cons. In this scope, hybrid network architectures have been recently proposed as a relevant solution. In this paper we propose a new hybrid architecture that is called P2PWeb, between the centralized client/server and the non-centralized P2P architectures for content delivery. The main objective of this proposal is to reduce the load over the server in order to provide a better Quality of Service (QoS) for the end-users. A new P2PWeb communication protocol has been implemented and deployed to reach the objective. The experimentation results and the performance evaluations that we have made show the efficiency of the proposed system in terms of QoS evaluations.

This paper provides a review of the state-of-the-art of major Programmable Logic Controller (PLC) based devices along with their security concerns. It discusses, mainly, the threats and vulnerabilities of PLCs and associated field devicesincluding local industrial networks. As PLC-BS are becoming more integrated and interconnected with other complex systems and open source solutions, they are becoming more vulnerable to critical threats and exploitations. Little attention and progress have been made in securing such devices if compared to that of securing overall Industrial Control Systems. This review shows the fact that major PLC based devices have several vulnerabilities and are insecure by design-firmware, code, or hardware. This paper suggests policies, recommendations, and countermeasures to secure PLC-BS. Securing PLC-BS is vital and crucial since a compromised PLC-BS would lead to significant financial loss and safety risks that could endanger human lives or the environment.

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