1,103 research outputs found

    Natural selection and the evolution of asynchronous aging

    Get PDF

    Improving the Energy Efficiency of Mobile Terminals Using Dynamic Multilevel Priority Packet Scheduling in Cooperative Communication

    Full text link
    Cooperative communication is an efficient method for reducing the energy consumption of mobile terminal in wireless cellular network. However, it is hard to implement due to the lack of motivations for the Mobile terminals to cooperate. For this scenario as the benchmark case, where the information of the helping mobile terminals such as the channel and battery conditions is completely known by the source node terminal, the problem is formulated as a relay selection problem. Efficient algorithms based on dichotomous search and alternative optimizations are proposed to solve the problem for the cases of split and non-split data at the source MT, respectively. The cooperative communications scheme with pricing mechanism can decrease both the battery outages and communications for the mobile node, and can also increase the average battery level during the mobile terminals operation. In this paper, we state a Dynamic Multilevel Priority (DMP) packet scheduling scheme. In the proposed system, each node, except those which are at the last level of the virtual hierarchy in the zone based topology of Wireless sensor network , have three levels of priority queues. Real-time packets are placed in the highest-priority queue and can preempt data packets in other queues. Non-real-time packets are placed in other two queues based on a certain threshold of their estimated processing time. Leaf nodes will have two queues for real-time and non-real-time data packets since they do not receive data from other nodes and so this reduce end to- end delay. The performance of the proposed Dynamic multilevel priority packet scheduling scheme through simulations for real-time and non-real-time data packet. Simulation results shows that the DMP packet scheduling scheme outperforms conventional schemes interms of average data waiting time and end-to-end delay

    FORMULATION AND EVALUATION OF ORAL SUSTAINED IN SITU GELLING SYSTEM OF ROXATIDINE

    Get PDF
    Gel dosage forms are successfully used as drug delivery systems to control drug release and protect the medicaments from a hostile environment. The main objective of this present work is to formulate and evaluate in situ gels of roxatidine for the treatment of peptic ulcer. This system utilizes polymers that exhibit sol-to-gel phase transition due to change in specific physico-chemical parameters. In the present work in situ gels have been developed by using gellan gum and sodium alginate based on the concept of ion activated systems. Sol-to-gel transformation occurred in the presence of monovalent/divalent cations. Formulations were evaluated for clarity, drug content, in vitro gelling capacity, determination of pH, in situ release study, viscosity, gel strength, ex vivo gelation and stability study. All the results found to be satisfactory. Experimental part showed that viscosity of sols and gel strength was increased with increase in the concentration of polymers, also drug release gets sustaining. The formulations were therapeutically efficacious, sterile and provided sustained release of the drug over a period of time. These results demonstrated that the developed system is an alternative to conventional drug delivery systems and can improve patient compliance.Key words: In situ gels, Roxatidine, Peptic ulcer

    BioNetGen 2.2: Advances in Rule-Based Modeling

    Full text link
    BioNetGen is an open-source software package for rule-based modeling of complex biochemical systems. Version 2.2 of the software introduces numerous new features for both model specification and simulation. Here, we report on these additions, discussing how they facilitate the construction, simulation, and analysis of larger and more complex models than previously possible.Comment: 3 pages, 1 figure, 1 supplementary text file. Supplementary text includes a brief discussion of the RK-PLA along with a performance analysis, two tables listing all new actions/arguments added in BioNetGen 2.2, and the "BioNetGen Quick Reference Guide". Accepted for publication in Bioinformatic

    Gender Differences in Frontotemporal Lobar Degeneration (FTLD) Support an Estrogenic Model of Delayed Onset

    Get PDF
    Gender differences in frontotemporal lobar degeneration (FTLD) have been reported in the literature but not well characterized or explored. In the present work, we propose that steroid hormone estrogens delay the onset of FTLD in pre-menopausal women compared to age equivalent men, and may provide neuroprotection in the early post-menopausal period. We present a model wherein estrogens serve a regulatory role in attenuating the microglia conversion from the benign to active form in response to cell stress that might otherwise trigger an inflammatory response. Via microglia stabilization, estrogens preserve the homeostasis of both the ubiquitin-proteosome degradation system and lysosome-autophagy recycling system. Both systems have been implicated in the genetic forms of FTLD, with the latter system recognized to be associated with the majority of them

    Influence of inversion on Mg mobility and electrochemistry in spinels

    Full text link
    Magnesium oxide and sulfide spinels have recently attracted interest as cathode and electrolyte materials for energy-dense Mg batteries, but their observed electrochemical performance depends strongly on synthesis conditions. Using first principles calculations and percolation theory, we explore the extent to which spinel inversion influences Mg2+^{2+} ionic mobility in MgMn2_2O4_4 as a prototypical cathode, and MgIn2_2S4_4 as a potential solid electrolyte. We find that spinel inversion and the resulting changes of the local cation ordering give rise to both increased and decreased Mg2+^{2+} migration barriers, along specific migration pathways, in the oxide as well as the sulfide. To quantify the impact of spinel inversion on macroscopic Mg2+^{2+} transport, we determine the percolation thresholds in both MgMn2_2O4_4 and MgIn2_2S4_4. Furthermore, we analyze the impact of inversion on the electrochemical properties of the MgMn2_2O4_4 cathode via changes in the phase behavior, average Mg insertion voltages and extractable capacities, at varying degrees of inversion. Our results confirm that inversion is a major performance limiting factor of Mg spinels and that synthesis techniques or compositions that stabilize the well-ordered spinel structure are crucial for the success of Mg spinels in multivalent batteries

    Design and Analysis of a Sustainable LV Residential Microgrid

    Get PDF
    AbstractIn the present scenario, power cuts are daily occurrences in many parts of the world. People all over the world would like to avoid these unscheduled power cuts and have a reliable, secure and clean electricity. For an affordable energy usage, sustainable power generation with renewable resources are highly recommended for environment friendly generation of energy with lower carbon footprints. They are isolated from the utility grid in case of any power outage or power blackouts. The key objective of this work is to model a self-sustained microgrid from the existing Indian distribution feeder, which means a small scale interconnected, centralized single controllable system where the particular arena is supplied with distributed energy resources like solar and wind instead of the main grid. The existing system of a particular region supplied with 42 bus system layout connected with 100 KVA transformer. Wind and the solar sources are designed individually and this hybrid energy is interconnected with the layout model to make up a small, modern self-sustained grid called the microgrid. The results are obtained in PSCAD software package with several case studies

    Experimentally reduced insulin/IGF-1 signaling in adulthood extends lifespan of parents and improves Darwinian fitness of their offspring

    Get PDF
    Classical theory maintains that ageing evolves via energy trade-offs between reproduction and survival leading to accumulation of unrepaired cellular damage with age. In contrast, the emerging new theory postulates that ageing evolves because of deleterious late-life hyper-function of reproduction-promoting genes leading to excessive biosynthesis in late-life. The hyper-function theory uniquely predicts that optimizing nutrient-sensing molecular signaling in adulthood can simultaneously postpone ageing and increase Darwinian fitness. Here, we show that reducing evolutionarily conserved insulin/IGF-1 nutrient-sensing signaling via daf-2 RNA interference (RNAi) fulfils this prediction in Caenorhabditis elegans nematodes. Long-lived daf-2 RNAi parents showed normal fecundity as self-fertilizing hermaphrodites and improved late-life reproduction when mated to males. Remarkably, the offspring of daf-2 RNAi parents had higher Darwinian fitness across three different genotypes. Thus, reduced nutrient-sensing signaling in adulthood improves both parental longevity and offspring fitness supporting the emerging view that suboptimal gene expression in late-life lies at the heart of ageing
    corecore