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  • Association of statin therapy with blood pressure control in hypertensive hypercholesterolemic outpatients in clinical practice
    Publication . Morgado, Manuel; Rolo, Sandra; Macedo, Ana Filipa; Castelo-Branco, Miguel
    Background: Some clinical evidence revealed that statins, apart from lowering cholesterol levels, also have an antihypertensive effect. Our aim was to evaluate the existence of a possible association of statin therapy with blood pressure (BP) control in clinical practice. Materials and Methods: Patients attending a hypertension/ dyslipidemia clinic were prospectively evaluated. Those patients with a diagnosis of stage 1 hypertension and hypercholesterolemia who consented to participate were included in the study, either in the statin group (when taking a statin) or in the control group (when not taking a statin). Exclusion criteria included dementia, pregnancy, or breastfeeding, and history or evidence of stage 2 hypertension. Detailed clinical information was prospectively obtained from medical records. A total of 110 hypertensive patients were assigned to the study (82 in the statin group and 28 in the control group). Results: Although there were no signifcant differences (P > 0.05) in both groups concerning gender, body mass index, antihypertensive pharmacotherapy, and serum levels of high-density lipoprotein cholesterol and triglycerides, a higher BP control was observed in the statin group (P = 0.002). Signifcantly lower systolic BP (−6.7 mmHg, P = 0.020) and diastolic BP (−6.4 mmHg, P = 0.002) levels were reported in the statin group. Serum levels of low-density lipoprotein were also signifcantly lower in the statin group (P < 0.001). Conclusions: This observational study detected an association of statin therapy with BP control in hypertensive hypercholesterolemic patients in clinical practice. These fndings raise the possibility that statin therapy may be useful for BP control in the studied population.
    2011-01Journal article Open access Show more
  • Cost-benefit aware routing protocol for wireless sensor networks with Hybrid Energy Storage System
    Publication . Pais, Nuno Miguel Esteves; Cetin, Bilge Karta; Pratas, Nuno; Velez, Fernando J.; Prasad, Neeli R.; Prasad, Ramjee
    At the eve of a new decade, when energy concerns are at the top of the research priorities, this work presents a new cost-benefit function for wireless sensor networks (WSNs) powered by harvesting energy sources. The models rely on a Hybrid Energy Storage System (HESS) that combines a super-capacitor (SC) with a Rechargeable Battery (RB). While the SC has low energy storage capability but is capable of providing high level of energy throughput and frequent charge cycles, the RB has higher energy storage capability but limited charge cycles. Our proposal for the protocol associated with HESS assigns different weights to the residual energy in both energy storage systems whilst favouring routes with more SC energy and harvesting rates. The main innovation is the application of a new routing cost metric to prolong the network lifetime. An energy model framework has been developed in MATLAB with different application scenarios to test the proposed cost metric. The simulation results show that, by using the HESS flexible energy-aware cost-benefit function, significant extension of the network lifetime is achieved by means a balance between the energy consumption and the reliable delivery of data packets.
    2011-01Journal article Open access Show more
  • Cost/Revenue Tradeoff in the Optimization of Fixed WiMAX Deployment With Relays
    Publication . Velez, Fernando J.; Nazir, Muhammad Kashif; Aghvami, A. Hamid; Holland, Oliver; Robalo, Daniel
    In fixed Worldwide Interoperability for Microwave Access (WiMAX), the contribution from each transmission mode can be incorporated into an implicit formulation to obtain the supported throughput as a function of the carrier-to-interference ratio. This is done by weighting the physical throughput in each concentric coverage ring by the size of the ring. In this paper, multihop cells are formed by a central coverage zone and three outer coverage zones, which are served by cheaper low-complexity relays. Although the reuse distance in this case is augmented by a factor of √3, we show that, with the use of relays in frequencydivision duplexing (FDD) mode with an adapted time-division duplexing (TDD) uplink (UL) subframe structure to accommodate communication from/to the relay station (RS) to/from subscriber station (SS), only the consideration of trisectored base stations (BSs) with a reuse pattern of K = 3enables attainment of values for the cell per sector throughput that is comparable with cases without the use of relays. Cost/revenue optimization results show that trisectored BSs in topologies with relays enable us to achieve more profitable reuse configurations than with omnidirectional BSs and no relays. Under the same total bandwidth and with the coverage distance set at R ∼ 500 m, we show that it is preferable to consider K = 1 with three carriers per sector instead of K = 3with one carrier per sector, whereby the profit in this case is increased from ∼1000% to ∼1450%. Furthermore, if the price [in (C/MB)] is increased from 0.0025 to 0.005, the achievable profit more than doubles.
    2011-01Journal article Open access Show more