No abstract

The data regarding the role of serum uric acid (SUA) along with subclinical inflammation in the context of hypertensive vascular damage are rather scarce and controversial. Towards this end, we assess the links between SUA, high-sensitivity CRP (hs-CRP), adiponectin and carotid to femoral pulse wave velocity (c-f PWV) in 292 subjects with never-treated stage I-II essential hypertension. On the basis of the median SUA levels (0.31 mmol l À1 ), the study population was divided into subjects with low (n ¼ 149) and high (n ¼ 143) SUA values. By multiple regression analysis, it was revealed that SUA was independently associated with log hs-CRP (R 2 ¼ 0.098; P ¼ 0.02), log adiponectin (R 2 ¼ 0.102; P ¼ 0.03), waist circumference (R 2 ¼ 0.049; P ¼ 0.04), 24-h systolic blood pressure (SBP) (R 2 ¼ 0.179; P ¼ 0.001) and estimated glomerular filtration rate (R 2 ¼ 0.156; b (s.e.) ¼ À0.169 (0.023); P ¼ 0.02). In addition, c-f PWV was independently associated with age (R 2 ¼ 0.116; Po0.0001), waist circumference (R 2 ¼ 0.088; Po0.0001), 24-h SBP (R 2 ¼ 0.167; P ¼ 0.001), log adiponectin (R 2 ¼ 0.07; P ¼ 0.006) and log hs-CRP (R 2 ¼ 0.06; P ¼ 0.034). In conclusion, SUA levels are independently associated with hs-CRP and adiponectin levels but not with c-f PWV in essential hypertensive patients. Increased SUA levels are accompanied by a state of pronounced inflammatory activation and hypoadiponectinemia that significantly impairs the arterial stiffness accelerating the vascular ageing process in this setting.

This paper is not a survey related to generic wireless sensor networks (WSNs), which have been largely treated in a number of survey papers addressing more focused issues; rather, it specifically addresses architectural aspects related to WSNs in some way connected with a satellite link, a topic that presents challenging interworking aspects. The main objective is to provide an overview of the potential role of a satellite segment in future WSNs. In this perspective, requirements of the most meaningful WSN applications have been drawn and matched to characteristics of various satellite/space systems in order to identify suitable integrated configurations. Copyright © 2012 John Wiley & Sons, Ltd.

No abstract

The incorporation of cognitive radio techniques in satellite communications has recently become a significant research challenge leading to the proposal of a novel network infrastructure known as cognitive satellite terrestrial networks. However, efficient resource management mechanisms should be proposed to provide a complete system analysis for this promising architecture. Towards this direction, this article focuses on the problem of power management in cognitive satellite terrestrial systems, where the satellite system has the role of the cognitive system, while the terrestrial represents the primary one. Particularly, a power control scheme for the satellite terminal is proposed. Taking into account the peculiarities of both systems and considering the uplink case, the goal of the proposed scheme is to optimise the performance of the satellite link without deteriorating the communication quality of the terrestrial link. To safeguard the communication of the terrestrial system, we introduce a novel interference-based constraint, which ensures a specific level for the inverse signal-to-interference plus noise ratio of the terrestrial link. Both the cases of perfect and imperfect channel estimation of terrestrial link are considered in order to study a more realistic scenario. Furthermore, for the imperfect case, a protection mechanism is proposed to guarantee the communication quality of the primary link that offsets the uncertainty of channel estimation. Simulation results evaluate the performance of the proposed scheme for various system parameters and verify its superiority compared with the well-known water-filling based power control scheme for both cases of perfect and imperfect channel estimation.