How the BoP configuration affects the performance in an air-cooled polymer electrolyte fuel cell. Keys to design the best configuration

Air Cooled Polymer Electrolyte fuel cells (AC-PEFC) are recently receiving especial attention because they offer the possibility to integrate the oxidant and cooling subsystems in just one. This feature reduces not only the fuel cell weight, volume and cost but also the control complexity. In these fuel cells, the Oxidant/Cooling subsystem along with three others (Fuel, Electrical and Control) make up the Balance of Plant (BoP), which together with the stack comprise the full fuel cell. It is common to find works focused on analysing the influence of the Oxidant/Cooling subsystem on the fuel cell. Nevertheless, studies in which the Fuel subsystem (it is responsible for providing the hydrogen for its reduction–oxidation reaction with oxygen to form water) is investigated are hard to find on the scientific literature. It seems like the Fuel subsystem configuration would not have influence over the whole system performance. Contrary to what one might think, and in basis on experimental results, this paper shows how the fuel cell performance is conditioned by the Fuel subsystem configuration. The aim of this paper is to present a comprehensive experimental study of an AC-PEFC paying particular attention, so unexplored so far, to Fuel subsystem configuration, giving the keys for the most suitable BoP configuration which guarantees the best performance, with the easiest BoP design and the lowest complexity

A review of energy management strategies for renewable hybrid energy systems with hydrogen backup

Hybrid systems are presented as a viable, safe and effective solution to minimize the associated problems of the dependence on renewable energies with the environmental resources. In this way different renewable systems such as photovoltaic, wind, hydrogen and so on, can work together to configure hybrid renewable systems. However, to make them work properly in a holistic way by creating synergies among them is not an easy task. Recently hydrogen technology has appeared as a promising technology to hybridize renewable energy systems, since it allows the generation (by electrolyzers) and storage of hydrogen when there is a surplus of energy in the system, and at a later time (e.g. when there are insufficient renewable resources available) using the stored hydrogen to generate electrical energy by fuel cells. The choice of a correct energy management strategy should guarantee an optimum performance of the whole hybrid renewable system; therefore, it is necessary to know the most important criteria in order to define a management strategy that ensures the best solution from a technical and economic point of view. This paper presents a critical review and analysis of different energy management strategies for hybrid renewable systems based on hydrogen backup. In the same way, a review is also presented of the most important technical and economic optimization criteria, as well as problems and solutions studied in the scientific literature

H2RES2 simulator. A new solution for hydrogen hybridization with renewable energy sources-based systems

This paper presents a new simulator for Hydrogen hybridization with Renewable Energy based Systems. The aim of this simulator is to provide a new solution for testing different energy management strategies of hydrogen hybridization based on renewable systems, in order to optimize them for implementation. The simulator uses the open architecture philosophy and has been developed in MATLAB®-SIMULINK environment. Its main feature is calculating technical and economical parameters for a deepened analysis of influences on energy management strategies. It considers each element of the hybrid system and the whole system function. A simulation case shows the proper functioning of the simulator

Air-cooled fuel cells: Keys to design and build the oxidant/cooling system

In the field of energy, hydrogen as an energetic vector is becoming increasingly important. Specifically, fuel cells powered by hydrogen are becoming an alternative in automotive and other fields because of their ability to produce electricity without any pollution. Therefore, at this time there is a very active research field. A fuel cell can be described as a scale down industrial plant that consists of different subsystems whose purpose is to make the stack works properly. Air Cooled Polymer Electrolyte Fuel Cells (AC-PEFC) are receiving special attention due to their potential to integrate the oxidant and cooling subsystems into one, which in term gives the fuel cells their capability to reduce its weight, volume, cost and control complexity. In these fuel cells, the Oxidant/Cooling subsystem is of crucial importance and along with three others (Fuel, Electrical and Control subsystems) make up the Balance of Plant (BoP), which together with the stack comprise the full fuel cell system. The aim of this paper is to present a comprehensive experimental study of an AC-PEFC paying particular attention to the Oxidant/Cooling subsystem configuration. According to the scientific literature, this subsystem has not received the same attention as other subsystems like the Fuel and Control subsystems. However, a suitable design and size is critical for the proper functioning of the stack. The analysis carried out in this paper tries to solve some problems that can appear if the design of the Oxidant/Cooling subsystem has not been optimized. These problems are related to important aspects such as the performance and the efficiency of the whole system and temperature distribution over the stack

PERSEIA: a biomedical wireless sensor network to support healthcare delivery for the elderly and chronically Ill

Proceeding of: 28th Annual International Conference of the IEEE Engineering in Medicine and Biology Society, 2006. EMBS ´06, New York, Aug. 30 2006-Sept. 3, 2006This paper presents a system based on Ambient Intelligence (AmI) to foster home care monitoring of senior citizens and chronically ill patients. The most important fact addressed in this research is the development of non intrusive and easy to use sensing devices. According to this, medical tests do not need user collaboration to perform them, neither powering on and off the sensor, starting the measure, configuring communications, etc.This work was supported in part by the Spanish Comunidad de Madrid under Grant GR/SAL/0277/2004.Publicad

INTERGROWTH-21st versus a customized method for the prediction of neonatal nutritional status in hypertensive disorders of pregnancy

Background Hypertensive disorders of pregnancy (HDP) generate complications and are one of the principal causes of maternal, foetal, and neonatal mortality worldwide. It has been observed that in pregnancies with HDP, the incidence of foetuses small for their gestational age (SGA) is twice as high as that in noncomplicated pregnancies. In women with HDP, the identification of foetuses (SGA) is substantially important, as management and follow-up are determined by this information. Objective The objective of this study was to evaluate whether the INTERGROWTH-21st method or customized birthweight references better identify newborns with an abnormal nutritional status resulting from HDP. Method A comparative analysis study was designed with two diagnostic methods for the prediction of neonatal nutritional status in pregnancies with HDP. The performance of both methods in identifying neonatal malnutrition (defined by a neonatal body mass index < 10(th) centile or a ponderal index < 10(th) centile) was assessed by calculating sensitivity, specificity, positive predictive value, negative predictive value, diagnostic odds ratio, Youden's index and probability ratios. Results The study included 226 pregnant women diagnosed with HDP. The customized method identified 45 foetuses as small for gestational age (19.9%), while the INTERGROWTH-21st method identified 27 newborns with SGA (11.9%). The difference between proportions was statistically significant (p < 0.01). Using body mass index (< 10(th) centile) as a measure of nutritional status, newborns identified as SGA by the customized method showed a higher risk of malnutrition than those identified as SGA by INTERGROWTH-21st (RR: 4.87 (95% CI: 1.86-12.77) vs. 3.75 (95% CI: 1.49-9.43)) (DOR: 5.56 (95% CI: 1.82-16.98) vs. 4.84 (95% CI: 1.51-15.54)) Even when using Ponderal index (< 10(th) centile), newborns identified as SGA by the customized method showed a higher risk of malnutrition than those identified as SGA by INTERGROWTH-21st (RR 2.37 (95% CI: 1.11-5.05) vs. 1.68 (95% CI: 0.70-4.03))(DOR 2.62 (95% CI: 1.00-6.87) vs. 1.90 (95% CI: 0.61-5.92)). Conclusion In pregnant women with HDP, the predictive ability of the customized foetal growth curves to identify neonatal malnutrition appears to surpass that of INTERGROWTH-21st

Dorsolateral prefrontal cortex and amygdala function during cognitive reappraisal predicts weight restoration and emotion regulation impairment in anorexia nervosa

Background: although deficits in affective processing are a core component of anorexia nervosa (AN), we lack a detailed characterization of the neurobiological underpinnings of emotion regulation impairment in AN. Moreover, it remains unclear whether these neural correlates scale with clinical outcomes. Methods: we investigated the neural correlates of negative emotion regulation in a sample of young women receiving day-hospital treatment for AN (n = 21) and healthy controls (n = 21). We aimed to determine whether aberrant brain activation patterns during emotion regulation predicted weight gain following treatment in AN patients and were linked to AN severity. To achieve this, participants completed a cognitive reappraisal paradigm during functional magnetic resonance imaging. Skin conductance response, as well as subjective distress ratings, were recorded to corroborate task engagement. Results: compared to controls, patients with AN showed reduced activation in the dorsolateral prefrontal cortex (dlPFC) during cognitive reappraisal [pFWE<0.05, threshold-free cluster enhancement (TFCE) corrected]. Importantly, psycho-physiological interaction analysis revealed reduced functional connectivity between the dlPFC and the amygdala in AN patients during emotion regulation (pFWE<0.05, TFCE corrected), and dlPFC-amygdala uncoupling was associated with emotion regulation deficits (r = -0.511, p = 0.018) and eating disorder severity (r = -0.565, p = .008) in the AN group. Finally, dlPFC activity positively correlated with increases in body mass index (r = 0.471, p = 0.042) and in body fat mass percentage (r = 0.605, p = 0.008) following 12 weeks of treatment. Conclusions: taken together, our findings indicate that individuals with AN present altered fronto-amygdalar response during cognitive reappraisal and that this response may serve as a predictor of response to treatment and be linked to clinical severity

Unexpected online gambling disorder in late-life: a case report

Background: The lifetime prevalence of problem or Gambling disorder (GD) in the elderly (i.e., those over 60 years old) is reported to range from 0.01 to 10.9%. Research has identified several specific risk factors and vulnerabilities in the elderly. Since the late 1990s, an increase in online GD has been observed in the youth population, whereas casinos, slot machines, and bingo seem to be the activities of choice among the elderly. Interestingly, online GD has not been described in the elderly to date. Case Description: We report an 83-year-old man who started online casino gambling from the age of 80 years, leading to debts that exceeded 30,000. He underwent a full clinical and neuropsychological assessment, without any evidence of cognitive impairment or any associated neurodegenerative disease. However, he had risk factors for GD, including adjustment disorder, stressful life events, previous of line casino GD when 50 years old, and dysfunctional personality traits. The change to online GD may have been due to his isolation, movement difficulties, and his high level of education, which facilitated his access to the Internet. Care management focused on individual cognitive-behavioral therapy. Conclusion: The prevalence of online GD may be underestimated among the elderly, and may increase among isolated old people with movement difficulties and ready access to the Internet. However, late-life GD should be considered a diagnosis of elimination, requiring a full medical, psychiatric (including suicide risk), and cognitive assessment. Specific therapeutic approaches need to be proposed and developed

Human amylin aggregates release within exosomes as a protective mechanism in pancreatic β cells: Pancreatic β-hippocampal cell communication

Pancreatic β cells are essential in the maintenance of glucose homeostasis during the progression to type 2 Diabetes Mellitus (T2DM), generating compensatory hyperinsulinemia to counteract insulin resistance. It is well known, that throughout the process there is an increased mTORC1 signaling pathway, with an impairment in different quality control systems including ubiquitin-proteasome system and autophagy. In addition, under this situation, pancreatic β cells start to accumulate amylin protein (IAPP) in aggregates, and this accumulation contributes to the failure of autophagy, damaging different organelles such as plasma membrane, endoplasmic reticulum, mitochondria, and others. Here, we report that IAPP can be incorporated to multivesicular bodies (MVB) and secreted into exosomes, a mechanism responsible for the exportation of these toxic aggregates as vehicles of cell to cell communication. On this regard, we have demonstrated that the exosomes bearing toxic hIAPP released from pancreatic β cells are capable to induce hyperactivation of mTORC1 signaling, a failure in the autophagic cellular quality control, and favor pro-fission status of the mitochondrial dynamics in hippo-campal cells. In summary, our results show that harmful accumulation of hIAPP in pancreatic β cells may be detoxified by the release of exosomes, which may be captured by endocytosis mechanism damaging neuronal hippocampal cells, which suggest an underlying molecular mechanism to the link between type 2 diabetes and neurodegenerative diseases