3,909 research outputs found

    3,7-Bis(dialkylamino)phenothiazin-5-ium derivatives: biomedical applications and biological activity

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    The light-induced reactions of 3,7-bis(dialkylamino)phenothiazin-5-ium compounds with biological substrates are briefly discussed. Their biomedical applications, in particular those related with biological staining, interaction with proteins and antiviral, antibacterial and antitumour activity are reviewed.info:eu-repo/semantics/publishedVersio

    Multi-q Pattern Classification of Polarization Curves

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    Several experimental measurements are expressed in the form of one-dimensional profiles, for which there is a scarcity of methodologies able to classify the pertinence of a given result to a specific group. The polarization curves that evaluate the corrosion kinetics of electrodes in corrosive media are an application where the behavior is chiefly analyzed from profiles. Polarization curves are indeed a classic method to determine the global kinetics of metallic electrodes, but the strong nonlinearity from different metals and alloys can overlap and the discrimination becomes a challenging problem. Moreover, even finding a typical curve from replicated tests requires subjective judgement. In this paper we used the so-called multi-q approach based on the Tsallis statistics in a classification engine to separate multiple polarization curve profiles of two stainless steels. We collected 48 experimental polarization curves in aqueous chloride medium of two stainless steel types, with different resistance against localized corrosion. Multi-q pattern analysis was then carried out on a wide potential range, from cathodic up to anodic regions. An excellent classification rate was obtained, at a success rate of 90%, 80%, and 83% for low (cathodic), high (anodic), and both potential ranges, respectively, using only 2% of the original profile data. These results show the potential of the proposed approach towards efficient, robust, systematic and automatic classification of highly non-linear profile curves.Comment: 12 pages, 7 figure

    Elastic provisioning of network and computing resources at the edge for IoT services

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    The fast growth of Internet-connected embedded devices demands new system capabilities at the network edge, such as provisioning local data services on both limited network and computational resources. The current contribution addresses the previous problem by enhancing the usage of scarce edge resources. It designs, deploys, and tests a new solution that incorporates the positive functional advantages offered by software-defined networking (SDN), network function virtual-ization (NFV), and fog computing (FC). Our proposal autonomously activates or deactivates embedded virtualized resources, in response to clients’ requests for edge services. Complementing existing literature, the obtained results from extensive tests on our programmable proposal show the superior performance of the proposed elastic edge resource provisioning algorithm, which also assumes a SDN controller with proactive OpenFlow behavior. According to our results, the maximum flow rate for the proactive controller is 15% higher; the maximum delay is 83% smaller; and the loss is 20% smaller compared to when the non-proactive controller is in operation. This improvement in flow quality is complemented by a reduction in control channel workload. The controller also records the time duration of each edge service session, which can enable the ac-counting of used resources per session.info:eu-repo/semantics/publishedVersio

    WLAN-UMTS integration to optimize MBMS provision

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    Provision of multimedia services with high bandwidth demands is constantly increasing its share in mobile systems. Aiming a more efficient distribution of multicast/broadcast contents in the UMTS networks, 3GPP introduced the Multimedia Broadcast Multicast Service (MBMS). Even though this technology brought significant improvements regarding the network efficiency, the UTRAN (UMTS Terrestrial Radio Access Network) remains the network’s most vulnerable area due to its shortage resources. The integration of wireless LAN (WLAN) access technology in cellular data networks to enhance their services coverage and increase data rates, is an extremely interesting solution for operators. In addition, this solution based on WLAN is easily deployed and can provide additional license-free bandwidth. Therefore, this paper addresses a possible WLAN integration, which uses a UMTS Access Point (UAP) that establishes a WLAN tunnel to provide MBMS data services to UEs with both UMTS and WLAN interfaces. Using this simulation environment, we pretend to measure and conclude about the benefits achieved from merging these two access technologies when delivering MBMS services.info:eu-repo/semantics/acceptedVersio
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