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This thesis proposes a new multi-homing mobile architecture for future heterogeneous network environment. First, a new multi-homed mobile architecture called Multi Network Switching enabled Mobile IPv6 (MNS-MIP6) is proposed which enables a Mobile Node (MN) having multiple communication paths between itself and its Correspondent Node (CN) to take full advantage of being multi-homed. Multiple communication paths exist because MN, CN, or both are simultaneously attached to multiple access networks. A new sub layer is introduced within IP layer of the host’s protocol stack. A context is established between the MN and the CN. Through this context, additional IP addresses are exchanged between the two. Our MNS-MIP6 architecture allows one communication to smoothly switch from one interface/communication path to another. This switch remains transparent to other layers above IP. Second, to make communication more reliable in multi-homed mobile environments, a new failure detection and recovery mechanism called Mobile Reach ability Protocol (M-REAP) is designed within the proposed MNS-MIP6 architecture. The analysis shows that our new mechanism makes communication more reliable than the existing failure detection and recovery procedures in multi-homed mobile environments. Third, a new network selection mechanism is introduced in the proposed architecture which enables a multi-homed MN to choose the network best suited for particular application traffic. A Policy Engine is defined which takes parameters from iv the available networks, compares them according to application profiles and user preferences, and chooses the best network. The results show that in multi-homed mobile environment, load can be shared among different networks/interfaces through our proposed load sharing mechanism. Fourth, a seamless handover procedure is introduced in the system which enables multi-homed MN to seamlessly roam in a heterogeneous network environment. Layer 2 triggers are defined which assist in handover process. When Signal to Noise Ratio (SNR) on a currently used active interface becomes low, a switch is made to a different active interface. We show through mathematical and simulation analysis that our proposed scheme outperforms the existing popular handover management enhancement scheme in MIPv6 networks namely Fast Handover for MIPv6 (FMIPv6). Finally, a mechanism is introduced to allow legacy hosts to communicate with MNS-MIP6 MNs and gain the benefits of reliability, load sharing and seamless handover. The mechanism involves introducing middle boxes in CN’s network. These boxes are called Proxy-MNS boxes. Context is established between the middle boxes and a multi-homed MN.

The mu-opioid receptor (MOR) has been shown to mediate morphine induced analgesia, addiction, and tolerance. The expression of the major product of the MOR (MOR-1) gene has been found to be driven by two promoters, a distal promoter and a proximal promoter. The proximal promoter region has been shown in previous studies to be the major promoter for the regulation of MOR gene transcription in the adult mouse brain and embryonic development. Recent studies have shown that single-stranded DNA binding proteins (such as Poly C Binding Protein) are involved in transcriptional regulation of mouse MOR gene. Poly C binding protein (PCBPs) is categorized in the family of hnRNP's, containing multiple K-Homology (KH) domains, which is involved in RNA stabilization, translational activation, and gene silencing. In this study, we attempted to determine the trans-activation domains of PCBP and examine the regulatory effects of each trans-activation domain of PCBP in MOR transcription. Mouse neuronal cells (N2A) were transiently transfected with various truncation constructs of PCBP to determine which domains were important in trans­ activation. Our preliminary data suggests that at least two KH domains were required for PCBP to display its trans-activation activity.