PEARL: a programmable virtual router platform

International audienceProgrammable routers supporting virtualization are a key building block for bridging the gap between new Internet protocols and their deployment in real operational networks. This article presents the design and implementation of PEARL, a programmable virtual router platform with relatively high performance. It offers high flexibility by allowing users to control the configuration of both hardware and software data paths. The platform makes use of fast lookup in hardware and software exceptions in commodity multicore CPUs to achieve highspeed packet processing. Multiple isolated packet streams and virtualization techniques ensure isolation among virtual router instances

Melatonin Orchestrates Lipid Homeostasis through the Hepatointestinal Circadian Clock and Microbiota during Constant Light Exposure

Misalignment between natural light rhythm and modern life activities induces disruption of the circadian rhythm. It is mainly evident that light at night (LAN) interferes with the human endocrine system and contributes to the increasing rates of obesity and lipid metabolic disease. Maintaining hepatointestinal circadian homeostasis is vital for improving lipid homeostasis. Melatonin is a chronobiotic substance that plays a main role in stabilizing bodily rhythm and has shown beneficial effects in protecting against obesity. Based on the dual effect of circadian rhythm regulation and antiobesity, we tested the effect of melatonin in mice under constant light exposure. Exposure to 24-h constant light (LL) increased weight and insulin resistance compared with those of the control group (12-h light−12-h dark cycle, LD), and simultaneous supplementation in the melatonin group (LLM) ameliorated this phenotype. Constant light exposure disturbed the expression pattern of a series of transcripts, including lipid metabolism, circadian regulation and nuclear receptors in the liver. Melatonin also showed beneficial effects in improving lipid metabolism and circadian rhythm homeostasis. Furthermore, the LL group had increased absorption and digestion of lipids in the intestine as evidenced by the elevated influx of lipids in the duodenum and decrease in the efflux of lipids in the jejunum. More interestingly, melatonin ameliorated the gut microbiota dysbiosis and improved lipid efflux from the intestine. Thus, these findings offer a novel clue regarding the obesity-promoting effect attributed to LAN and suggest a possibility for obesity therapy by melatonin in which melatonin could ameliorate rhythm disorder and intestinal dysbiosis

Pollution-Aware Walking in 16 Countries:An Application of the Theory of Planned Behaviour (TPB)

Background: The current levels of air pollution in European countries reduces life expectancy by an average of 8 months. People who actively travel by walking have a higher level of exposure to air pollution than those who use motor vehicles or electric buses. Some routes have higher air pollution levels than others, but little is known about pollution-aware route choice and intentions to actively avoid walking near polluted roads. An improved understanding of how air pollution influences intentions to walk or avoid polluted routes can inform interventions to decrease exposure. The present investigation has three aims: (1) compare experiences walking near roads with high levels of air pollution across countries; (2) identify groups of countries based on perceptions of air quality; and (3) examine how pedestrians develop their intentions of avoiding pollution using the extended TPB (demographics, social norms, attitudes, perceived control, and perceived risk).Methods: A cross-sectional design was applied. Pedestrians were asked about their experiences walking near roads with high levels of air pollution. To identify groups of countries with different levels of air pollution, a cluster analysis was implemented based on the perceptions of air quality. Finally, regressions were used to predict pedestrians’ intentions to avoid polluted roads per country group using the extended TPB.Results: 6180 respondents (Age M(SD)= 29.4(14.2); Males= 39.2%) ranging from 12.6% from Russia to 2.2% from Finland completed the questionnaire. The proportion of participants who reported never walking near air polluted roads was 12.4% (from 3% in Brazil to 54% in Japan). Seven groups of countries were identified using perceptions of air quality: G1(Japan, Mexico, Colombia, Turkey, Malaysia & Brazil), G2(Spain, Romania & Czechia), G3(Chile, Russia & Peru), G4(China), G5(Australia), G6(Finland), and G7(Portugal). Participants in China (G4) and Australia (G5) reported the worst and best air quality respectively. Across all countries, intentions to avoid polluted roads were associated with perceptions of risk. TPB-psychosocial factors such as social norms and perceived behavioural control also influenced intention in most groups. Favourable TPB-beliefs and low perceived risk increase intentions to avoid polluted routes.Conclusions: The willingness of pedestrians to walk on or near roads with high levels of air pollution differs significantly among countries in this study. Countries can be grouped based on their perceived air quality. Perceived risk was the only common predictor of intention to avoid polluted routes across the different groups of countries

The Role of PPAR and Its Cross-Talk with CAR and LXR in Obesity and Atherosclerosis

The prevalence of obesity and atherosclerosis has substantially increased worldwide over the past several decades. Peroxisome proliferator-activated receptors (PPARs), as fatty acids sensors, have been therapeutic targets in several human lipid metabolic diseases, such as obesity, atherosclerosis, diabetes, hyperlipidaemia, and non-alcoholic fatty liver disease. Constitutive androstane receptor (CAR) and liver X receptors (LXRs) were also reported as potential therapeutic targets for the treatment of obesity and atherosclerosis, respectively. Further clarification of the internal relationships between these three lipid metabolic nuclear receptors is necessary to enable drug discovery. In this review, we mainly summarized the cross-talk of PPARs-CAR in obesity and PPARs-LXRs in atherosclerosis

Optimal Cache Allocation for Content-Centric Networking

Abstract—Content-Centric Networking (CCN) is a promising framework for evolving the current network architecture, advocating ubiquitous in-network caching to enhance content delivery. Consequently, in CCN, each router has storage space to cache frequently requested content. In this work, we focus on the cache allocation problem: namely, how to distribute the cache capacity across routers under a constrained total storage budget for the network. We formulate this problem as a content placement problem and obtain the exact optimal solution by a two-step method. Through simulations, we use this algorithm to investigate the factors that affect the optimal cache allocation in CCN, such as the network topology and the popularity of content. We find that a highly heterogeneous topology tends to put most of the capacity over a few central nodes. On the other hand, heterogeneous content popularity has the opposite effect, by spreading capacity across far more nodes. Using our findings, we make observations on how network operators could best deploy CCN caches capacity. I

Thermoplastic Rubber (TPR) Modified by a Silane Coupling Agent and Its Influence on the Mechanical Properties of Oil Well Cement Pastes

The surface hydrophilicity of thermoplastic rubber (TPR) is poor, and the effect of using it directly in oil well cement is not good. TPR was modified by different silane coupling agents, and the hydrophilicity of the modified TPR was studied by Fourier-transform infrared (FT-IR) spectroscopy and dispersion stability photography. The application effect of modified TPR in oil well cement slurry was also evaluated. The fracture surface morphology of TPR cement stone was observed by macrophotography and scanning electron microscopy (SEM). The results demonstrated that the hydrophilicity of TPR particles was improved after modification with silane coupling agent 3-methacryloxypropyltrimethoxysilane (KH570), and its application effect in cement slurry was excellent. Compared with the pure cement paste, the compressive strength of the cement paste with addition of TPR modified by KH570 was reduced, but the flexural strength and impact strength of the cement paste were effectively enhanced. Moreover, the modified TPR greatly improved the deformation capacity and decreased the elastic modulus of the cement paste. The modified TPR particles formed a plastic polymer network structure in the cement stone and penetrated the cement hydration products, filling in the cement paste to form a flexible structural center. Thus, it improved the mechanical properties and reduced the brittleness of cement paste