Institute of Biomedical Research August Pi Sunyer IDIBAPS

Barcelona, Spain

Institute of Biomedical Research August Pi Sunyer IDIBAPS

Barcelona, Spain
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Otal B.,Institute of Biomedical Research August Pi Sunyer IDIBAPS | Alonso L.,Polytechnic University of Catalonia | Verikoukis C.,Catalonia Technology Center of Telecomunications
Eurasip Journal on Wireless Communications and Networking | Year: 2010

The fact that the IEEE 802.15.4 MAC does not fully satisfy the strict wireless body sensor network (BSN) requirements in healthcare systems highlights the need for the design and analysis of new scalable MAC solutions, which guarantee low power consumption to all specific sorts of body sensors and traffic loads. While taking the challenging healthcare requirements into account, this paper aims for the study of energy consumption in BSN scenarios. For that purpose, the IEEE 802.15.4 MAC limitations are first examined, and other potential MAC layer alternatives are further explored. Our intent is to introduce energy-aware radio activation polices into a high-performance distributed queuing medium access control (DQ-MAC) protocol and evaluate its energy-saving achievements, as a function of the network load and the packet length. To do so, a fundamental energy-efficiency theoretical analysis for DQ-MAC protocols is hereby for the first time provided. By means of computer simulations, its performance is validated using IEEE 802.15.4 MAC system parameters. Copyright © 2010 Begonya Otal et al.


Otal B.,Institute of Biomedical Research August Pi Sunyer IDIBAPS | Alonso L.,Polytechnic University of Catalonia | Verikoukis C.,Catalonia Technology Center of Telecomunications
Sensors | Year: 2011

The aging population and the high quality of life expectations in our society lead to the need of more efficient and affordable healthcare solutions. For this reason, this paper aims for the optimization of Medium Access Control (MAC) protocols for biomedical wireless sensor networks or wireless Body Sensor Networks (BSNs). The hereby presented schemes always have in mind the efficient management of channel resources and the overall minimization of sensors' energy consumption in order to prolong sensors' battery life. The fact that the IEEE 802.15.4 MAC does not fully satisfy BSN requirements highlights the need for the design of new scalable MAC solutions, which guarantee low-power consumption to the maximum number of body sensors in high density areas (i.e., in saturation conditions). In order to emphasize IEEE 802.15.4 MAC limitations, this article presents a detailed overview of this de facto standard for Wireless Sensor Networks (WSNs), which serves as a link for the introduction and initial description of our here proposed Distributed Queuing (DQ) MAC protocol for BSN scenarios. Within this framework, an extensive DQ MAC energy-consumption analysis in saturation conditions is presented to be able to evaluate its performance in relation to IEEE 802.5.4 MAC in highly dense BSNs. The obtained results show that the proposed scheme outperforms IEEE 802.15.4 MAC in average energy consumption per information bit, thus providing a better overall performance that scales appropriately to BSNs under high traffic conditions. These benefits are obtained by eliminating back-off periods and collisions in data packet transmissions, while minimizing the control overhead. © 2011 by the authors; licensee MDPI, Basel, Switzerland.


Sepulcre J.,University of Navarra | Peraita H.,Spanish University for Distance Education (UNED) | Goni J.,University of Navarra | Arrondo G.,University of Navarra | And 6 more authors.
Journal of Clinical and Experimental Neuropsychology | Year: 2011

The aim of the study was to analyze lexical access strategies in patients with multiple sclerosis (MS) and their changes over time. We studied lexical access strategies during semantic and phonemic verbal fluency tests and also confrontation naming in a 2-year prospective cohort of 45 MS patients and 20 healthy controls. At baseline, switching lexical access strategy (both in semantic and in phonemic verbal fluency tests) and confrontation naming were significantly impaired in MS patients compared with controls. After 2 years follow-up, switching score decreased, and cluster size increased over time in semantic verbal fluency tasks, suggesting a failure in the retrieval of lexical information rather than an impairment of the lexical pool. In conclusion, these findings underline the significant presence of lexical access problems in patients with MS and could point out their key role in the alterations of high-level communications abilities in MS. © 2010 Psychology Press, an imprint of the Taylor & Francis Group, an Informa business.


Catafau A.M.,Barcelona Imaging Group SL | Catafau A.M.,Institute of Biomedical Research August Pi Sunyer IDIBAPS | Bullich S.,Institute of Biomedical Research August Pi Sunyer IDIBAPS
Current Medicinal Chemistry | Year: 2013

The need for innovation in research is leading to an increased use of imaging biomarkers, which have shown to reduce timings and increase productivity, thus saving costs. PET and SPECT neurotransmission imaging has shown usefulness in the discovery and development of drugs for the central nervous system, providing unique information on drug-target interactions in the living human brain. Among the different therapeutic areas, antipsychotic drugs pioneered the application of these technologies in early phases of development. PET and SPECT radioligands for the most commonly targeted neurotransmission systems in the development of these drugs, such as the dopaminergic and serotoninergic systems are available, thus fostering the inclusion of PET and SPECT studies in the antipsychotic drug development plans. Radioligands for other neurotransmission systems more recently implicated in the pathophysiology of schizophrenia, such as the glutamatergic system, are being currently investigated. This review focuses on neurotransmission PET and SPECT aiming to serve as guidance for procedure requirements and methodology choices to be applied in antipsychotic drug development, through specific examples. Cutting-edge study designs and quantification approaches will be reviewed. Finally, some clues to get the most out of the PET and SPECT studies in the development of antipsychotic drugs will be provided. © 2013 Bentham Science Publishers.


PubMed | Institute of Biomedical Research August Pi Sunyer IDIBAPS
Type: Journal Article | Journal: Sensors (Basel, Switzerland) | Year: 2012

The aging population and the high quality of life expectations in our society lead to the need of more efficient and affordable healthcare solutions. For this reason, this paper aims for the optimization of Medium Access Control (MAC) protocols for biomedical wireless sensor networks or wireless Body Sensor Networks (BSNs). The hereby presented schemes always have in mind the efficient management of channel resources and the overall minimization of sensors energy consumption in order to prolong sensors battery life. The fact that the IEEE 802.15.4 MAC does not fully satisfy BSN requirements highlights the need for the design of new scalable MAC solutions, which guarantee low-power consumption to the maximum number of body sensors in high density areas (i.e., in saturation conditions). In order to emphasize IEEE 802.15.4 MAC limitations, this article presents a detailed overview of this de facto standard for Wireless Sensor Networks (WSNs), which serves as a link for the introduction and initial description of our here proposed Distributed Queuing (DQ) MAC protocol for BSN scenarios. Within this framework, an extensive DQ MAC energy-consumption analysis in saturation conditions is presented to be able to evaluate its performance in relation to IEEE 802.5.4 MAC in highly dense BSNs. The obtained results show that the proposed scheme outperforms IEEE 802.15.4 MAC in average energy consumption per information bit, thus providing a better overall performance that scales appropriately to BSNs under high traffic conditions. These benefits are obtained by eliminating back-off periods and collisions in data packet transmissions, while minimizing the control overhead.

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