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SUMMARY Mobile Worldwide Interoperability for Microwave Access networks usually provide flexible sleep-mode operations that allow mobile stations to conserve energy during sleep or active mode. For example, the IEEE 802.16e/m standard presents three power-saving classes that can be associated with different types of network connections to decrease the power consumption of mobile stations. However, previous studies failed to fully use the sleep-mode features to save energy of a mobile station while simultaneously maintaining unicast and multicast/broadcast connections. This study proposes an energy-efficient packet scheduling algorithm for both multicast and broadcast services that does not violate the QoS requirements of real-time connections. The proposed activity aggregation selection mechanism approach can minimize total power consumption of mobile stations in one cell and simultaneously satisfy the QoS of real-time connections. This method improves energy efficiency for IEEE 802.16e/m and the activity aggregation selection mechanism approach can optimize sleeping mode features to save the energy of mobile stations with overlapping connection packets The simulations in this study verified the proposed approach.Copyright © 2012 John Wiley & Sons, Ltd.

Because the bandwidth usage of wireless transmission is limited, one of the major research topics in this field is to improve system throughput by supporting multiple users with limited bandwidth resources. Although there are several studies on cross-layer designs for improving system throughput, previous research on quality-of-service guarantee and fairness are relatively rare. This study proposes a cross-layer subcarrier permutation (CLSP) mechanism that uses cross-layer strategies to select suboptimal subcarriers. Service flows simulations in the IEEE 802.16e system indicate that CLSP achieved a lower delay time and a long-term fairness among multiple users. Experimental results further show that the throughput of CLSP is 28 percent higher than that of the partial usage of subchannels model using the orthogonal frequency division multiple access technique. Copyright © 2011 John Wiley & Sons, Ltd.

Liver receptor homolog-1 (LRH-1; NR5A2) is an orphan member of the nuclear receptor superfamily, mainly expressed in endoderm-derived tissues and in the ovary. In ovarian granulosa and luteal cells, LRH-1 regulates the expression of genes associated with ovarian steroidogenesis. LRH-1 can be transported to transcriptionally inactive nuclear bodies after conjugation with small ubiquitin-related modifier (SUMO). In the present study, we investigated the effects of SUMO modification at five lysine residues of LRH-1 in rat granulosa cells. Lysine 289 could be conjugated with SUMO-1 in vitro, and the mutation K289R increased transcriptional activity of LRH-1, suggesting that SUMO conjugation is associated with transcription repression. Coexpression of SUMO-1 targets LRH-1 to the dot-like nuclear bodies, but the effect of lysine mutations on blocking subnuclear localization depended on the cell type. In COS-7 cells, mutation of either K173 or K289 prevented SUMO-1-mediated translocation of LRH-1 into nuclear bodies and also reduced the conjugation by SUMO-1, suggesting that K289 and K173 are two important sites involved in SUMO-1 modification. In granulosa cells, three or more altered lysine residues were required for nucleoplasm retention. This result suggests that multiple lysine residues are targets for SUMO conjugation in vivo and granulosa cells are more sensitive to SUMO-1-mediated LRH-1 localization to nuclear bodies. Nuclear body localization of LRH-1 was suppressed by forskolin and cholera toxin. Forskolin treatment obviously influences the expression of members involved in the SUMO pathway. The results obtained in the present study suggest that cAMP signaling could change the dynamic process of sumoylation and repress LRH-1 targeting to nuclear speckles in rat granulosa cells.