Lucent Optics (United States)

Objective. Neuroprosthetics hold tremendous promise to restore function through brain-computer interfaced devices. However, clinical applications of implantable microelectrodes remain limited given the challenges of maintaining neuronal signals for extended periods of time and with multiple biological mechanisms negatively affecting electrode performance. Acute and chronic inflammation, oxidative stress, and blood brain barrier disruption contribute to inconsistent electrode performance. We hypothesized that therapeutic hypothermia (TH) applied at the microelectrode insertion site will positively modulate both inflammatory and apoptotic pathways, promoting neuroprotection and improved performance in the long-term. Approach. A custom device and thermoelectric system were designed to deliver controlled TH locally to the cortical implant site at the time of microelectrode array insertion and immediately following surgery. The TH paradigm was derived from in vivo cortical temperature measurements and finite element modeling of temperature distribution profiles in the cortex. Male Sprague-Dawley rats were implanted with non-functional Utah microelectrodes arrays (UMEA) consisting of 4 × 4 grid of 1.5 mm long parylene-coated silicon shanks. In one group, TH was applied to the implant site for two hours following the UMEA implantation, while the other group was implanted under normothermic conditions without treatment. At 48 h, 72 h, 7 d and 14 d post-implantation, mRNA expression levels for genes associated with inflammation and apoptosis were compared between normothermic and hypothermia-treated groups. Main results. The custom system delivered controlled TH to the cortical implant site and the numerical models confirmed that the temperature decrease was confined locally. Furthermore, a one-time application of TH post UMEA insertion significantly reduced the acute inflammatory response with a reduction in the expression of inflammatory regulating cytokines and chemokines. Significance. This work provides evidence that acutely applied hypothermia is effective in significantly reducing acute inflammation post intracortical electrode implantation.

Virtualization and cloud transformation are already revolutionizing the data center environments and are promising to bring the same cloud economics to general networking. Software Defined Networking is a prime enabler for the transition to cloud networking.

Large enterprises are increasingly running applications that demand the storage and real time transfer of massive amounts of data. Such applications require high bandwidth and low latency in order to meet current operational business needs and disaster recovery time objectives. Critical enterprise data is synchronously mirrored between two geographically diverse datacenters, typically at least 60 to 100 kilometers apart, to ensure that no data will be lost if disaster should strike. This paper will explore complementary technologies to Dense Wave Division Multiplexing (DWDM) in order to address current datacenter challenges specific to business continuity and security in light of the potential for equipment failure, fiber cuts, floods, fire, or massive power grid blackouts, as well as denial of service and terrorist attacks. These include intrusion detection on the optical fiber path, line speed encryption, and multiple mechanisms to address the potential for major outages. The combination of these technologies mitigates the risks present to critical datacenter infrastructure. © 2012 Alcatel-Lucent.

Big things come in small packages; a particularly apt description of small cell deployment in cellular networks. Small cells have a big role to play in orchestrating a cellular network that can overcome the explosive mobile traffic upsurge at little cost to the network operator. However, if left unchecked, a large-scale small cell deployment can substantially increase the network energy consumption with strong ecological and economic implications. In this article, we introduce energy-efficient SLEEP mode algorithms for small cell base stations in a bid to reduce cellular networks' power consumption. The designed algorithms allow the hardware components in the BS to be astutely switched off in idle conditions, such that the energy consumption is modulated over the variations in traffic load. Three different strategies for algorithm control are discussed, relying on small cell driven, core network driven, and user equipment driven approaches. Based on a mixed voice and data traffic model, the algorithms present energy saving opportunities of approximately 10-60 percent in the network with respect to no SLEEP mode activation in small cells, coupled with additional capacity incentives.

The rapid growth of wireless voice subscribers; the growth of the Internet; and the increasing use of portable computing devices suggest that wireless Internet access will rise rapidly over the next few years. Transmission rates are currently only about 10 kb/s for large cell systems. Third generation wireless access and the evolution of second-generation systems will provide bit rates of 50 to 384 kb/s in macrocellular systems. This paper discusses packet data transmission rates of 2 to 5 Mb/s in macrocellular environments and up to 10 Mb/s in microcellular and indoor environments as a complementary service to evolving second and third generation wireless systems. Dynamic packet assignment for high efficiency resource management and packet admission; OFDM at the physical layer with interference suppression, space-time coding and frequency diversity; as well as smart antennas to obtain good power and spectral efficiency are discussed.