266 research outputs found

    Optimal Policies for Status Update Generation in a Wireless System with Heterogeneous Traffic

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    A large body of applications that involve monitoring, decision making, and forecasting require timely status updates for their efficient operation. Age of Information (AoI) is a newly proposed metric that effectively captures this requirement. Recent research on the subject has derived AoI optimal policies for the generation of status updates and AoI optimal packet queueing disciplines. Unlike previous research we focus on low-end devices that typically support monitoring applications in the context of the Internet of Things. We acknowledge that these devices host a diverse set of applications some of which are AoI sensitive while others are not. Furthermore, due to their limited computational resources they typically utilize a simple First-In First-Out (FIFO) queueing discipline. We consider the problem of optimally controlling the status update generation process for a system with a source-destination pair that communicates via a wireless link, whereby the source node is comprised of a FIFO queue and two applications, one that is AoI sensitive and one that is not. We formulate this problem as a dynamic programming problem and utilize the framework of Markov Decision Processes to derive optimal policies for the generation of status update packets. Due to the lack of comparable methods in the literature, we compare the derived optimal policies against baseline policies, such as the zero-wait policy, and investigate the performance of all policies for a variety of network configurations. Results indicate that existing status update policies fail to capture the trade-off between frequent generation of status updates and queueing delay and thus perform poorly

    Re(I) tricarbonyl complex of 1,10-phenanthroline-5,6-dione: DNA binding, cytotoxicity, antiinflammatory and anti-coagulant effects towards platelet activating factor

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    The complex fac-[Re(CO)3(phendione)Cl] (1) (where phendione = 1,10-phenanthroline-5,6-dione) has been synthesized and fully characterized by UV–visible, FTIR, and NMR techniques. The DNA binding properties of 1 are investigated by UV-spectrophotometric (melting curves), covalent binding assay, CV (cyclic voltammetry), circular dichroism (CD) and viscosity measurements. Experimental data indicate that 1 fits into the major groove without disrupting the helical structure of the B-DNA in contrast to the free phendione which intercalates within the base pairs of DNA. Upon irradiation, complex 1promotes the cleavage of plasmid pBR322 DNA from supercoiled form I to nicked form II via a proton coupled electron transfer mechanism. This comes as a result of experimental data in anaerobic/aerobic conditions and in the presence of DMSO. The biological activities of 1 and its precursors [Re(CO)5Cl] and phendione are tested towards a series of cancerous cell lines as glioblastoma (T98G), prostate cancer (PC3) and breast cancer (MCF-7) as well as platelet activating factor (PAF)-aggregation. Moreover, all the aforementioned compounds are tested for their ability to modulate PAF-basic metabolic enzyme activities in preparations of rabbit leukolytes. The in vitro experiments indicate that phendione has a better antitumor effect than cisplatin whereas [Re(CO)5Cl] is a better PAF inhibitor than both the phendione ligand and 1. Moreover, for the first time it is indicated that [Re(CO)5Cl], with a IC50 of 17 nM is comparable to the widely used PAF receptor antagonists, BN52021 and WEB2170 with IC50 of 30 and 20 nM, respectively, whereas 1 affects PAF-catabolism

    Short sleep duration across income, education, and race/ethnic groups: population prevalence and growing disparities during 34 years of follow-up.

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    http://deepblue.lib.umich.edu/bitstream/2027.42/62464/1/Short-Sleep-Duration-Across-Income,-Education,-and-RaceEthnic-Groups-Population-Prevalence-and-Growing-Disparities-During-34-Years-of-Follow-Up_2007_Annals-of-Epi.pd

    A systematic review of correlates of sedentary behaviour in adults aged 18–65 years: a socio-ecological approach

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    Background: Recent research shows that sedentary behaviour is associated with adverse cardio-metabolic consequences even among those considered sufficiently physically active. In order to successfully develop interventions to address this unhealthy behaviour, factors that influence sedentariness need to be identified and fully understood. The aim of this review is to identify individual, social, environmental, and policy-related determinants or correlates of sedentary behaviours among adults aged 18-65 years. Methods: PubMed, Embase, CINAHL, PsycINFO and Web of Science were searched for articles published between January 2000 and September 2015. The search strategy was based on four key elements and their synonyms: (a) sedentary behaviour (b) correlates (c) types of sedentary behaviours (d) types of correlates. Articles were included if information relating to sedentary behaviour in adults (18-65 years) was reported. Studies on samples selected by disease were excluded. The full protocol is available from PROSPERO (PROSPERO 2014:CRD42014009823). Results: 74 original studies were identified out of 4041: 71 observational, two qualitative and one experimental study. Sedentary behaviour was primarily measured as self-reported screen leisure time and total sitting time. In 15 studies, objectively measured total sedentary time was reported: accelerometry (n = 14) and heart rate (n = 1). Individual level factors such as age, physical activity levels, body mass index, socio-economic status and mood were all significantly correlated with sedentariness. A trend towards increased amounts of leisure screen time was identified in those married or cohabiting while having children resulted in less total sitting time. Several environmental correlates were identified including proximity of green space, neighbourhood walkability and safety and weather. Conclusions: Results provide further evidence relating to several already recognised individual level factors and preliminary evidence relating to social and environmental factors that should be further investigated. Most studies relied upon cross-sectional design limiting causal inference and the heterogeneity of the sedentary measures prevented direct comparison of findings. Future research necessitates longitudinal study designs, exploration of policy-related factors, further exploration of environmental factors, analysis of inter-relationships between identified factors and better classification of sedentary behaviour domains

    Changes in objectively measured activity behavior among women undergoing breast cancer treatment: Longitudinal cohort study

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    Purpose: Activity behaviors of breast cancer survivors (BCSs) during treatment are unlikely to be at levels sufficient enough to gain health benefits. Previous activity research among BCSs has been mainly posttreatment and generally cross-sectional. This study aimed to determine the prevalence and changes in objectively measured moderate-to-vigorous physical activity (MVPA), light physical activity (LPA), and sedentary behavior (SED) among BCSs undergoing adjuvant/palliative therapy.Methods: Participants completed baseline surveys and wore accelerometers to measure activity during waking hours during treatment and again 6 months later. Hierarchal linear modeling (HLM) was used to determine changes.Results: In total, 77 BCSs participated. Ninety-one percent provided physical activity (PA) data for 3 or more valid days at baseline (T1) and 72% at 6 months (T2); 29% met PA guidelines at T1 and 41% at T2. Daily LPA and SED did not change from T1 to T2 (133 vs 138 minutes; 595 vs 597 minutes). Controlling for body mass index at the intercept, HLM revealed that MVPA significantly increased from T1 to T2 (+5.62; P = .015).Conclusion: An increase in objectively measured total daily MVPA over 6 months was found, at which time, fewer BCSs were currently receiving chemo- or radiotherapy and may theoretically be feeling better. However, fewer T2 measures may bias and artificially inflate the results. Although total MVPA minutes increased at T2, less than half BCSs were meeting guidelines and had high amounts of LPA/SED during treatment, with insignificant change over time (71% at T1; 59% at T2). Practitioner intervention may help reduce SED while increasing LPA and MVPA behavior among those currently undergoing treatment

    Divergent Innate and Epithelial Functions of the RNA-Binding Protein HuR in Intestinal Inflammation

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    HuR is an abundant RNA-binding protein acting as a post-transcriptional regulator of many RNAs including mRNAs encoding inflammatory mediators, cytokines, death signalers and cell cycle regulators. In the context of intestinal pathologies, elevated HuR is considered to enhance the stability and the translation of pro-tumorigenic mRNAs providing the rationale for its pharmacological targeting. However, HuR also possesses specific regulatory functions for innate immunity and cytokine mRNA control which can oppose intestinal inflammation and tumor promotion. Here, we aim to identify contexts of intestinal inflammation where the innate immune and the epithelial functions of HuR converge or diverge. To address this, we use a disease-oriented phenotypic approach using mice lacking HuR either in intestinal epithelia or myeloid-derived immune compartments. These mice were compared for their responses to (a) Chemically induced Colitis; (b) Colitis- associated Cancer (CAC); (c) T-cell mediated enterotoxicity; (d) Citrobacter rodentium-induced colitis; and (e) TNF-driven inflammatory bowel disease. Convergent functions of epithelial and myeloid HuR included their requirement for suppressing inflammation in chemically induced colitis and their redundancies in chronic TNF-driven IBD and microbiota control. In the other contexts however, their functions diversified. Epithelial HuR was required to protect the epithelial barrier from acute inflammatory or infectious degeneration but also to promote tumor growth. In contrast, myeloid HuR was required to suppress the beneficial inflammation for pathogen clearance and tumor suppression. This cellular dichotomy in HuR's functions was validated further in mice engineered to express ubiquitously higher levels of HuR which displayed diminished pathologic and beneficial inflammatory responses, resistance to epithelial damage yet a heightened susceptibility to CAC. Our study demonstrates that epithelial and myeloid HuR affect different cellular dynamics in the intestine that need to be carefully considered for its pharmacological exploitation and points toward potential windows for harnessing HuR functions in intestinal inflammation
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