Delta opioid peptide [D-Ala2,D-leu5]enkephalin blocks the long-term loss of dopamine transporters induced by multiple administrations of methamphetamine: involvement of opioid receptors and reactive oxygen species

Delta opioid peptide [D-Ala2,D-leu5]enkephalin (DADLE) can prolong organ preservation and increases myocardial tolerance to ischemia. Our study examined the protective property of DADLE against methamphetamine- (METH) induced dopaminergic terminal damage in the central nervous system. Because the neurotoxicity of METH involves reactive oxygen species, we also examined if DADLE might be an antioxidative agent in vitro. DADLE at 2 and 4 mg/kg (i.p.), given 30 min before each METH administration (5 or 10 mg/kg, i.p., four injections in a day at 2-hr intervals), dose-dependently blocked the METH-induced long-term dopamine transporter loss. The opioid antagonist naltrexone blocked this action of DADLE in both aspects of striata but tends not to affect the effects of DADLE in the nucleus accumbens. DADLE did not alter changes in body temperature induced by METH. The reduction of striatal dopaminergic content and tyrosine hydroxylase activity caused by METH, however, were not blocked by DADLE. In vitro, DADLE was approximately equipotent to glutathione in inhibiting both superoxide anion formation induced by xanthine oxidase and hydroxyl radical formation evoked by ferrous/citrate complex. DADLE was only slightly less potent than glutathione in inhibiting the iron/ascorbate-induced brain lipid peroxidation. These results suggest that DADLE can protect the terminal membranes of dopaminergic neurons against METH-induced insult but not the loss of dopaminergic content and tyrosine hydroxylase activity and that this action of DADLE might involve opioid receptors as well as the sequestration of free radical.     

Zodiac: A history-based interactive video authoring system

Easy-to-use audio/video authoring tools play a crucial role in moving multimedia software from research curiosity to mainstream applications. However, research in multimedia authoring systems has rarely been documented in the literature. This paper describes the design and implementation of an interactive video authoring system called Zodiac, which employs an innovative edit history abstraction to support several unique editing features not found in existing commercial and research video editing systems. Zodiac provides users a conceptually clean and semantically powerful branching history model of edit operations to organize the authoring process, and to navigate among versions of authored documents. In addition, by analyzing the edit history, Zodiac is able to reliably detect a composed video stream's shot and scene boundaries, which facilitates interactive video browsing. Zodiac also features a video object annotation capability that allows users to associate annotations to moving objects in a video sequence. The annotations themselves could be text, image, audio, or video. Zodiac is built on top of MMFS, a file system specifically designed for interactive multimedia development environments, and implements an internal buffer manager that supports transparent lossless compression/decompression. Shot/scene detection, video object annotation, and buffer management all exploit the edit history information for performance optimization.     

Differential wavelength-scanning heterodyne interferometer for measuring large step height

An interferometer based on the differential heterodyne configuration and wavelength-scanning interferometry for measuring large step heights is presented. The proposed interferometer is less sensitive to environmental disturbances than other interferometers and can accurately measure interference phases. A tunable diode laser is utilized to illuminate the interferometer and thus solve the phase ambiguity problem. Counting the interference fringes as the wavelength is scanned through a known change in wavelength directly determines the step height. Three gauge blocks of different lengths, 5, 10, and 50 mm, are individually wrung on a steel plate to simulate large step heights. Comparing the results measured by the proposed interferometer with those by the gauge block interferometer reveals that the accuracy is approximately 100 nm.     

OmniCon: a Mobile IP‐based vertical handoff system for wireless LAN and GPRS links

Wi‐Fi based hotspots offer mobile users broadband wireless Internet connectivity in public work spaces and corporate/university campuses. Despite the aggressive deployment of these hotspots in recent years, high‐speed wireless Internet access remains restricted to small geographical areas due to the limited physical coverage of wireless LANs. On the other hand, despite their lower throughput, cellular networks have a significantly wider coverage and are thus much more available. Recognizing that 2.5G or 3G cellular networks can effectively complement wireless LANs, we set out to develop a vertical handoff system that allows mobile users to seamlessly fall back to such cellular networks as the general packet radio service (GPRS) or 3G whenever wireless LAN connectivity is not available. The resulting handoff mechanism allows a network connection of a mobile node to operate over multiple wireless access networks in a way that is transparent to end user applications. In this paper, we present the design, implementation, and evaluation of a fully operational vertical handoff system, called OmniCon, which enables mobile nodes to automatically switch between wireless LAN and GPRS, based on wireless LAN availability, by introducing a simple extension to the existing Mobile IP implementation. We discuss the design issues in the proposed vertical handoff system for heterogeneous networks, including connection setup problems due to network address translation, and the disparity in link characteristics between wireless LANs and GPRS. A detailed performance evaluation study of the OmniCon prototype demonstrates its ability to migrate active network connections between these two wireless technologies with low handoff latency and close to zero packet loss. Copyright © 2006 John Wiley & Sons, Ltd.     

Cache memory design for Internet processors

As a result of the exploding bandwidth demand from the Internet, network router and switch designers are designing and fabricating a growing number of microchips specifically for networking devices rather than traditional computing applications. In particular, a new breed of microprocessors, called Internet processors, has emerged that is designed to efficiently execute network protocols on various types of internetworking devices including switches, routers, and application-level gateways. We evaluate a series of three progressively more aggressive routing-table cache designs and demonstrate that the incorporation of hardware caches into Internet processors, combined with efficient caching algorithms can significantly improve overall packet forwarding performance     

The integration of real-time I/O and network support in the StonyBrook Video Server

Stony Brook Video Server (SBVS) is an Ethernet-based video server from the Experimental Computer Systems Laboratory, SUNY at Stony Brook, and has been fully operational for over a year. The SBVS employs only off-the-shelf PC components and is capable of guaranteeing real-time delivery of digital video streams from the server's disk subsystem, through a shared LAN, to an end user's display. The SBVS integrates a real-time software-based disk array with the Real-Time Ethernet Protocol to provide end-to-end bandwidth guarantee. This article describes in detail how the real-time I/O subsystem interacts with the RETHER subsystem, and the performance cost of this integration. The most recent version of SBVS, a Pentium-90 PC with a six-drive disk array, can support up to 45 simultaneous MPEG-1 (1.5 Mb/s) streams with a single 100 Mb/s Ethernet link, and up to 65 streams with two 100 Mb/s Ethernet links     

Low complexity frequency-domain despreading for cyclic-prefix CDMA systems

In this letter, a frequency-domain despreading method for the cyclic-prefix code-division multiple-access (CP-CDMA) system is introduced. Using the orthogonality transformation property of the discrete Fourier transform (DFT), we can despread the received CP-CDMA signals in the frequency domain. Moreover, we propose an efficient architecture for the proposed frequency-domain despreader. Comparison with the conventional time-domain despreading approach shows that the proposed architecture can save a large amount of computation. The proposed scheme is therefore suitable for efficient implementation of CP-CDMA receivers that adopt frequency-domain equalization and despreading.     

Low-latency mobile IP handoff for infrastructure-mode wireless LANs

The increasing popularity of IEEE 802.11-based wireless local area networks (LANs) lends them credibility as a viable alternative to third-generation (3G) wireless technologies. Even though wireless LANs support much higher channel bandwidth than 3G networks, their network-layer handoff latency is still too high to be usable for interactive multimedia applications such as voice over IP or video streaming. Specifically, the peculiarities of commercially available IEEE 802.11b wireless LAN hardware prevent existing mobile Internet protocol (IP) implementations from achieving subsecond Mobile IP handoff latency when the wireless LANs are operating in the infrastructure mode, which is also the prevailing operating mode used in most deployed IEEE 802.11b LANs. In this paper, we propose a low-latency mobile IP handoff scheme that can reduce the handoff latency of infrastructure-mode wireless LANs to less than 100 ms, the fastest known handoff performance for such networks. The proposed scheme overcomes the inability of mobility software to sense the signal strengths of multiple-access points when operating in an infrastructure-mode wireless LAN. It expedites link-layer handoff detection and speeds up network-layer handoff by replaying cached foreign agent advertisements. The proposed scheme strictly adheres to the mobile IP standard specification, and does not require any modifications to existing mobile IP implementations. That is, the proposed mechanism is completely transparent to the existing mobile IP software installed on mobile nodes and wired nodes. As a demonstration of this technology, we show how this low-latency handoff scheme together with a wireless LAN bandwidth guarantee mechanism supports undisrupted playback of remote video streams on mobile stations that are traveling across wireless LAN segments.     

Assessing the environmental impact of five Pd-based catalytic technologies in removing of nitrates

Emerging technologies involving chemical catalytic processes to remove nitrate from water have proven efficient and cost-effective. However, the environmental impact of noble metals and metals at the nanoscale used in these processes has become a topic of serious concern. The aim of this research was to develop a system for evaluating the environmental impact of technologies associated with Pd-based catalytic denitrification. This research performed life cycle assessment (LCA) based on a detailed analysis of the technologies to examine the environmental burden associated with all stages of the removal process. We then applied analytical hierarchy process (AHP) to determine the weights of various burdens. We implemented the proposed system to determine the relative environmental friendliness of 5 processes used for the removal of nitrate. These five methods use Cu-Pd/TNTs, H₂ + Pd-Cu/TiO₂, Pd-Cu/TiO₂, Pd/ZnO, and Pd-Cu/FeO as catalysts for the removal of nitrate. The results indicate that the use of palladium and the consumption of electricity have a major environmental impact; while the use of Pd-Cu/TiO₂ as catalyst was the most environmentally friendly of the five processes evaluated.