ASSESSMENT OF BIOAVAILABILITY OF HEAVY METALS AFTER VERMICOMPOSTING IN THE PRESENCE OF ELECTRONIC WASTE

ABSTRACT Heavy metals contained in electronic waste, if discarded improperly, can become bioavailable after vermicomposting, posing a risk to the environment. Small-scale vermicomposting experiments were carried out with printed circuit boards (PCBs) to investigate the migration of heavy metals (Cu, Pb, Zn, Ni, and Sn) to the final compost, as well as the mobility and bioavailability of these metals. High total levels of Pb, Sn and Cu in samples of manure with electronic waste (MEW) and vegetables with electronic waste (VEW) were detected. Based on the initial metal levels in the PCBs and their concentration in the resulting compost, the order of migration of these metals to the MEW and VEW samples was Sn (23.1 %)>Pb (18.4 %)>Ni (4.63 %)>Zn (0.46 %)>Cu (0.14 %) and Sn (24.3 %)>Pb (23.6 %)>Ni (11.33 %)>Zn (1.76 %)>Cu (0.60 %), respectively. Mobility and bioavailability of these metals in the compost were evaluated by three-stage sequential extraction, where F1 was the exchangeable fraction, F2 the organic fraction and F3 the residual fraction. The bioavailability factor (BF) was calculated by the ratio of the sum of fractions F1 and F2 divided by the total sum of the fractions (F1 + F2 + F3). The highest bioavailability factor (BF = 0.92) was found for Pb, the heavy metal considered the greatest environmental concern in this study, indicating the high mobility and the possibility of becoming bioavailable of this metal.

Media, investors and bubbles

We analysed the specific case of how information in the financial press influences economic bubbles. We found considerable flaws in the information market due to several factors: demand, the predominance of what are termed “irrational investors” (herding), and supply, which has the problem that the sources of information are biasedand feeds. A financial bubble is a deviation between real value of a financial asset and its persistent market price in time, which also has a speculative origin fed back by the illusion of the owners of these financial values, who will take benefits because of the future prices, which must be higher than the previous ones. The economical information in the media is submitting three problems. First of all, it is information generated by companies. In second place, the information circuit is fed back. A problem of informative independence becomes created, particularly serious in the case of the banks, which are very were as creditors. And in a third place, some informative biases are manifested for the companies of regulated sectors which are starring the economical information in the media.

The limits of brain determinacy.

The genes do not control everything that happens in a cell or an organism, because thermally induced molecular movements and conformation changes are beyond genetic control. The importance of uncontrolled events has been argued from the differences between isogenic organisms reared in virtually identical environments, but these might alternatively be attributed to subtle, undetected differences in the environment. The present review focuses on the uncontrolled events themselves in the context of the developing brain. These are considered at cellular and circuit levels because even if cellular physiology was perfectly controlled by the genes (which it is not), the interactions between different cells might still be uncoordinated. A further complication is that the brain contains mechanisms that buffer noise and others that amplify it. The final resultant of the battle between these contrary mechanisms is that developmental stochasticity is sufficiently low to make neurobehavioural defects uncommon, but a chance component of neural development remains. Thus, our brains and behaviour are not entirely determined by a combination of genes-plus-environment.

Analysis of linear networks with inconsistent initial conditions

This paper presents a new method to analyze timeinvariant linear networks allowing the existence of inconsistent initial conditions. This method is based on the use of distributions and state equations. Any time-invariant linear network can be analyzed. The network can involve any kind of pure or controlled sources. Also, the transferences of energy that occur at t=O are determined, and the concept of connection energy is introduced. The algorithms are easily implemented in a computer program.

Calbindin D-28K and parvalbumin immunoreactivity in the frontal cortex in patients with frontal lobe dementia of non-Alzheimer type associated with amyotrophic lateral sclerosis

The morphology and distribution of local-circuit neurons (interneurons) were examined, by calbindin D-28k and parvalbumin immunocytochemistry, in the frontal cortex (area 8) in two patients with frontal lobe dementia of non-Alzheimer type associated with classical amyotrophic lateral sclerosis (ALS), and in seven normal cases. The density of calbindin D-28k immunoreactive cells was dramatically reduced in ALS patients, but the density of parvalbumin-immunoreactive neurons was preserved. Decreased density of calbindin D-28k-immunoreactive neurons, which are mainly located in the upper cortical layers, may interfere with the normal processing of cortico-cortical connections, whereas integrity of parvalbumin-immunoreactive cells may be associated with the preservation of the major inhibitory intracortical circuits in patients with frontal lobe dementia.

Mechanosensory interactions drive collective behaviour in Drosophila.

Collective behaviour enhances environmental sensing and decision-making in groups of animals. Experimental and theoretical investigations of schooling fish, flocking birds and human crowds have demonstrated that simple interactions between individuals can explain emergent group dynamics. These findings indicate the existence of neural circuits that support distributed behaviours, but the molecular and cellular identities of relevant sensory pathways are unknown. Here we show that Drosophila melanogaster exhibits collective responses to an aversive odour: individual flies weakly avoid the stimulus, but groups show enhanced escape reactions. Using high-resolution behavioural tracking, computational simulations, genetic perturbations, neural silencing and optogenetic activation we demonstrate that this collective odour avoidance arises from cascades of appendage touch interactions between pairs of flies. Inter-fly touch sensing and collective behaviour require the activity of distal leg mechanosensory sensilla neurons and the mechanosensory channel NOMPC. Remarkably, through these inter-fly encounters, wild-type flies can elicit avoidance behaviour in mutant animals that cannot sense the odour--a basic form of communication. Our data highlight the unexpected importance of social context in the sensory responses of a solitary species and open the door to a neural-circuit-level understanding of collective behaviour in animal groups.

Energy expenditure and postprandial thermogenesis in obese women before and after weight loss.

In six young obese women (mean weight 85 +/- 3 kg) with a childhood history of obesity, and in six young nonobese women (mean weight 55 +/- 2 kg), the energy expenditure was measured during 24 h in a respiratory chamber with a maintenance energy intake. The next day, the thermogenic response to a mixed meal was investigated by using an open circuit indirect calorimetry hood system. In addition, five of the same obese women were similarly studied after a mean weight loss of 12.1 kg (14% of initial body weight) consecutive to an 11-wk hypocaloric diet (protein-supplemented modified fast). Expressed in absolute terms, the total 24 h and basal energy expenditures were found to be significantly greater in the obese (2208 +/- 105 and 1661 +/- 56 kcal/24 h, respectively) than in the controls (1746 +/- 61 and 1230 +/- 40 kcal/24 h, respectively). After weight loss, both the total 24-h and the basal energy expenditures were significantly reduced (2009 +/- 99 kcal/24 h and 1423 +/- 43 kcal/24 h respectively), but both values were still greater than that of the control subjects. The thermogenic response to the mixed meal (a liquid diet containing 17, 54, and 29% as protein, carbohydrate, and lipid calories, respectively, and an energy level determined to cover 60% of the basal energy expenditure computed for 24 h) was found to be significantly reduced in the obese as compared to controls (ie, 7.6 +/- 0.4% versus 9.5 +/- 0.4% of the energy content of the load, respectively, p less than 0.025). After weight loss, the postprandial thermogenesis of the obese was still markedly reduced (ie, 6.2 +/- 0.8%). Both before and after weight loss, the relative increase in diurnal urinary norepinephrine excretion was found to be lower in the obese than in controls, when compared to the nocturnal values. These results show that the greater 24 h energy expenditure of obese women is entirely due to their higher basal metabolic rate. The lower thermogenic response to the meal in the obese supports the concept of a thermogenic defect which can favor energy gain; furthermore, the unchanged response after weight loss in the obese suggests that the thermogenic defect may be a cause rather than a consequence of obesity.

Hypoxia-induced inhibition of epithelial Na(+) channels in the lung. Role of Nedd4-2 and the ubiquitin-proteasome pathway.

Transepithelial sodium transport via alveolar epithelial Na(+) channels (ENaC) and Na(+),K(+)-ATPase constitutes the driving force for removal of alveolar edema fluid. Alveolar hypoxia associated with pulmonary edema may impair ENaC activity and alveolar Na(+) absorption through a decrease of ENaC subunit expression at the apical membrane of alveolar epithelial cells (AECs). Here, we investigated the mechanism(s) involved in this process in vivo in the β-Liddle mouse strain mice carrying a truncation of β-ENaC C-terminus abolishing the interaction between β-ENaC and the ubiquitin protein-ligase Nedd4-2 that targets the channel for endocytosis and degradation and in vitro in rat AECs. Hypoxia (8% O2 for 24 h) reduced amiloride-sensitive alveolar fluid clearance by 69% in wild-type mice but had no effect in homozygous mutated β-Liddle littermates. In vitro, acute exposure of AECs to hypoxia (0.5-3% O2 for 1-6 h) rapidly decreased transepithelial Na(+) transport as assessed by equivalent short-circuit current Ieq and the amiloride-sensitive component of Na(+) current across the apical membrane, reflecting ENaC activity. Hypoxia induced a decrease of ENaC subunit expression in the apical membrane of AECs with no change in intracellular expression and induced a 2-fold increase in α-ENaC polyubiquitination. Hypoxic inhibition of amiloride-sensitive Ieq was fully prevented by preincubation with the proteasome inhibitors MG132 and lactacystin or with the antioxidant N-acetyl-cysteine. Our data strongly suggest that Nedd4-2-mediated ubiquitination of ENaC leading to endocytosis and degradation of apical Na(+) channels is a key feature of hypoxia-induced inhibition of transepithelial alveolar Na(+) transport.

A phase I pharmacokinetic study of hypoxic abdominal stop-flow perfusion with gemcitabine in patients with advanced pancreatic cancer and refractory malignant ascites

PURPOSE: As no curative treatment for advanced pancreatic and biliary cancer with malignant ascites exists, new modalities possibly improving the response to available chemotherapies must be explored. This phase I study assesses the feasibility, tolerability and pharmacokinetics of a regional treatment of gemcitabine administered in escalating doses by the stop-flow approach to patients with advanced abdominal malignancies (adenocarcinoma of the pancreas, n = 8, and cholangiocarcinoma of the liver, n = 1). EXPERIMENTAL DESIGN: Gemcitabine at 500, 750 and 1,125 mg/m(2) was administered to three patients at each dose level by loco-regional chemotherapy, using hypoxic abdominal stop-flow perfusion. This was achieved by an aorto-caval occlusion by balloon catheters connected to an extracorporeal circuit. Gemcitabine and its main metabolite 2',2'-difluorodeoxyuridine (dFdU) concentrations were measured by high performance liquid chromatography with UV detection in the extracorporeal circuit during the 20 min of stop-flow perfusion, and in peripheral plasma for 420 min. Blood gases were monitored during the stop-flow perfusion and hypoxia was considered stringent if two of the following endpoints were met: pH </= 7.2, pO(2) nadir ratio </=0.70 or pCO(2) peak ratio >/=1.35. The tolerability of this procedure was also assessed. RESULTS: Stringent hypoxia was achieved in four patients. Very high levels of gemcitabine were rapidly reached in the extracorporeal circuit during the 20 min of stop-flow perfusion, with C (max) levels in the abdominal circuit of 246 (+/-37%), 2,039 (+/-77%) and 4,780 (+/-7.3%) mug/ml for the three dose levels 500, 750 and 1,125 mg/m(2), respectively. These C (max) were between 13 (+/-51%) and 290 (+/-12%) times higher than those measured in the peripheral plasma. Similarly, the abdominal exposure to gemcitabine, calculated as AUC(t0-20), was between 5.5 (+/-43%) and 200 (+/-66%)-fold higher than the systemic exposure. Loco-regional exposure to gemcitabine was statistically higher in presence of stringent hypoxia (P < 0.01 for C (max) and AUC(t0-20), both normalised to the gemcitabine dose). Toxicities were acceptable considering the complexity of the procedure and were mostly hepatic; it was not possible to differentiate the respective contributions of systemic and regional exposures. A significant correlation (P < 0.05) was found between systemic C (max) of gemcitabine and the nadir of both leucocytes and neutrophils. CONCLUSIONS: Regional exposure to gemcitabine-the current standard drug for advanced adenocarcinoma of the pancreas-can be markedly enhanced using an optimised hypoxic stop-flow perfusion technique, with acceptable toxicities up to a dose of 1,125 mg/m(2). However, the activity of gemcitabine under hypoxic conditions is not as firmly established as that of other drugs such as mitomycin C, melphalan or tirapazamine. Further studies of this investigational modality, but with bioreductive drugs, are therefore warranted first to evaluate the tolerance in a phase I study and later on to assess whether it does improve the response to chemotherapy.

FY 2013 ICN Report of Savings

Iowa Code section 8D.10 requires certain state agencies prepare an annual report to the General Assembly certifying the identified savings associated with that state agency's use of the Iowa Communications Network (ICN). This report covers estimated cost savings related to video conferencing via ICN for the Iowa Department of Transportation (DOT). In January 2012 the Iowa DOT requested the ISDN video circuit be disconnected which closed its ICN account.

Solar Powered Highway Delineator System, HR-367, 1993

Currently, many drivers experience some difficulty in viewing the road ahead of them during times of reduced visibility, such as rain, snow, fog, or the darkness of night- Recent studies done by the National Safety Council provide a detailed contrast between fatal accidents occurring during the day and night. Revealed was that the motor vehicle night death rate (4.41 deaths per 100 million miles driven) was sharply higher than the corresponding death rate during daylight hours (1.21). By providing a delineating system powered by the natural resource of solar power, a constant source of visibility may be maintained throughout the evening. Along with providing enough light to trace the outline of the road, other major goals defined in producing this delineator system are as follows: 1. A strong and durable design that would protect the internal components and survive extreme weather conditions. 2. A low maintenance system where components need few repairs or replacements. 3. A design which makes all components accessible in the event that maintenance is needed, but also prevents vandalism. 4. A design that provides greater visibility to drivers and will not harm a vehicle or its passengers in the event of a collision. This solar powered highway delineator consists of an adjustable solar array, a light fixture, and a standard delineator pole. The solar array houses and protects the solar panels, and can be easily adjusted to obtain a maximum amount of sunlight. The light fixture primarily houses the battery, the circuit and the light assembly. Both components allow for easy accessibility and reduce vandalism using internal connections for bolts and wires. The delineator mounting pole is designed to extensively deform in the event of a collision, therefore reducing any harm caused to the vehicle and/or the passengers. The cost of a single prototype to be produced is approximately $70.00 excluding labor costs. However, these material and labor costs will be greatly reduced if a large number of delineators are produced. It is recommended that the Iowa Department of Transportation take full advantage of the research and development put into this delineator design. The principles used in creating this delineator can be used to provide an outline for drivers to follow, or on a larger scale, provide actual roadway lighting in areas where it was never before possible or economically feasible. In either event, the number of fatal accidents will be decreased due to the improved driver visibility in the evening.

Novel action of a wake-promoting neuropeptide in hippocampus : inhibition of nmda receptor function at excitatory synapses through orexin-a

One of the most intriguing functions of the brain is the ability to learn and memorize. The mechanism through which memory and learning are expressed requires the activation of NMDA receptors (NMDARs). These molecular entities are placed at the postsynaptic density of excitatory synapses and their function is tightly controlled by the actions of several modulators at the extracellular, intracellular and pore sites. A large part of the intracellular modulation comes from the action of G-protein coupled receptors (GPCRs). Through intracellular cascades typically involving kinases and phosphatases, GPCRs potentiate or inhibit NMDARs, controlling the conductive state but also the trafficking within the synapse. The GPCRs are involved in the modulation of a variety of brain functions. Many of them control cognition, memory and learning performance, therefore, their effects on NMDARs are extensively studied. The orexinergic system signals through GPCRs and it is well known for the regulation of waking, feeding, reward and autonomic functions. Moreover, it is involved in potentiating hippocampus-related cognitive tasks. Orexin receptors and fibers are present within the hippocampus, but whether these directly modulate hippocampal cells and synapses has not yet been determined. During my thesis, I studied orexinergic actions on excitatory synaptic transmission via whole-cell patch-clamp recordings in rat acute hippocampal slices. I observed that exogenously applied orexin-A (ox-A) exerted a strong inhibitory action on NMDAR-mediated synaptic potentials at mossy fiber (MF)-CA3 synapses, by postsynaptically activating orexin-2 receptors, a minor inhibition at Schaffer collateral-CAl synapses and did not affect other synapses with the CA3 area. Moreover, I demonstrated that the susceptibility of NMDARs to ox- A depends on the tone of endogenous orexin known to fluctuate during the day-night cycle. In fact, in slices prepared during the active period of the rats, when endogenous orexin levels are high, NMDAR-currents were not affected by exogenously applied ox-A. The inhibitory effect of ox-A was, however, reverted when interfering with the orexinergic system through intraperitoneal injections of almorexant, a dual orexin receptor antagonist, during the active phase prior to slice preparation. This thesis work suggests that the orexinergic system regulates NMDAR-dependent information flow through select hippocampal pathways depending on the time-of-day. The specific orexinergic modulation of NMDARs at MFs dampens the excitability of the hippocampal circuit and could impede the mechanisms related to memory formation, possibly also following extended periods of waking. -- La capacité d'apprentissage et de mémorisation est une des fonctions les plus intrigantes de notre cerveau. Il a été montré qu'elles requièrent l'activation des récepteurs NMDA (NMDARs). Ces entités moléculaires sont présentes au niveau de la densité post-synaptique des synapses excitatrices et leur fonction est étroitement contrôlée par l'action de nombreux modulateurs au niveau extracellulaire, intracellulaire et membranaire de ces récepteurs. Une grande partie de la modulation intracellulaire s'effectue via l'action de récepteurs couplés aux protéines G (GPCRs). Grace à leurs cascades intracellulaires typiquement impliquant des kinases et des phosphatases, les GPCRs favorisent l'activation ou l'inhibition des NMDARs, contrôlant ainsi leur perméabilité mais aussi leur mouvement à la synapse. Les GPCRs sont impliquées dans de nombreuses fonctions cérébrales telles que la cognition, la mémoire ainsi que la capacité d'apprentissage c'est pour cela que leurs effets sur les NMDARs sont très étudiés. Le système orexinergique fait intervenir ces GPCRs et est connu par son rôle dans la régulation de fonctions physiologiques telles que l'éveil, la prise alimentaire, la récompense ainsi que d'autres fonctions du système nerveux autonome. De plus, ce système est impliqué dans la régulation de tâches cognitives liées à l'hippocampe. Bien que les fibres et les récepteurs à l'orexine soient présents dans l'hippocampe, leur mécanisme d'action sur les cellules et les synapses de l'hippocampe n'a pas encore été élucidé. Durant ma thèse, je me suis intéressée aux effets de l'orexine sur la transmission synaptique excitatrice en utilisant la méthode d'enregistrement en patch-clamp en configuration cellule entière sur des tranches aiguës d'hippocampes de rats. J'ai observé que l'application exogène d'orexine A d'une part inhibe fortement les courants synaptiques dépendants de l'activation des NMDARs au niveau de la synapse entre les fibres moussues et CA3 via l'activation post-synaptique des orexine récepteurs 2 mais d'autre part n'inhibe que de façon mineure la synapse entre les collatérales de Schaffer et CAI et n'affecte pas les autres synapses impliquant CA3. J'ai également démontré que la sensibilité des NMDARs à l'orexine A dépend de sa concentration endogène qui fluctue durant le cycle éveil-sommeil. En effet, lorsque les coupes d'hippocampes sont préparées durant la période active de l'animal correspondant à un niveau endogène d'orexine élevé, l'application exogène d'orexine A n'a aucun effet sur les courants dépendants de l'activation des NMDARs. Cependant, l'injection dans le péritoine, durant la phase active de l'animal, d'un antagoniste des orexine récepteurs, l'almorexant, va supprimer l'effet inhibiteur de l'orexine A. Les résultats de ma thèse suggèrent donc que le système orexinergique module les informations véhiculées par les NMDARs via des voies de signalisation sélectives de l'hippocampe en fonction du moment de la journée. La modulation orexinergique des NMDARs au niveau des fibres moussues diminue ainsi l'excitabilité du circuit hippocampal et pourrait entraver les mécanismes liés à la formation de la mémoire, potentiellement après de longues périodes d'éveil.

Ex-PRESS R-50 miniature glaucoma implant insertion under the conjunctiva combined with cataract extraction

Rapport de synthèse : Le glaucome à angle ouvert est une neuropathie optique chronique progressive pour laquelle de nombreux traitements tant médicaux que chirurgicaux ont été proposés. La prise en charge chirurgicale s'articule principalement autour de deux chirurgies filtrantes, la trabéculectomie et la sclérectomie profonde avec implant de collagène. Cependant, les complications postopératoires de ces deux interventions étant relativement fréquentes, la recherche s'est orientée vers des traitements alternatifs dont la mise en place de micro-drains. Ces implants de drainage diminuent la pression intraoculaire en créant un court-circuit du flux d'humeur aqueuse de la chambre antérieure vers l'espace sous-conjonctival avec formation d'une bulle de filtration. L'implant Ex-PRESS R-50 est un implant miniature (2.5 mm de long pour 400 µm de diamètre) en acier inoxydable et biocompatible. La présente étude s'est proposée d'étudier l'efficacité et la sécurité de l'implant miniature Ex-Press R-50 lors d'une opération combinée cataracte-glaucome. Trente-cinq yeux de 35 patients (âge moyen: 75 ans) ont été inclus dans l'étude. Tous les patients ont bénéficié d'une opération de la cataracte par phacoemulsification et mise en place d'un implant de chambre postérieure suivie de l'implantation du micro-drain. Les pressions intraoculaires préopératoires et postopératoires, la meilleure acuité visuelle corrigée, le nombre de médicaments anti-glaucomateux ainsi que le type et le nombre de complications ont été évalués mensuellement puis tous les 6 mois pendant 4 ans. Le succès total a été défini par une pression postopératoire finale inférieure à 18mmHg sans traitement médical associé, le succès partiel par une pression postopératoire finale inférieure à 18mmHg avec ou sans traitement médical associé.. Le suivi moyen a été de 36.9 mois avec une baisse de la pression intraoculaire significative d'environ 25%. Une augmentation de l'acuité visuelle a été observée après l'opération de la cataracte et le nombre de médicaments anti-glaucomateux a été réduit de 57%. Dix patients ont bénéficié d'un traitement supplémentaire de la bulle de filtration par injection d'anti-métabolite (mitomycine C). Nous avons observé 8 complications majeures (4 érosions conjonctivales et 4 obstructions de l'orifice interne du micro-drain), toutes suivies de l'ablation de l'implant et de la réalisation d'une chirurgie classique du glaucome. En se basant sur les courbes de Kaplan-Meier à 48 mois, le taux de succès total était de 32.7% et le succès partiel de 53.7%. Nous pouvons conclure suite à ce travail que l'implant miniature Ex-PRESS R-50 est associé à un nombre trop élevé de complications, même si les cas non compliqués ont bénéficié d'une baisse significative de la pression intraoculaire. La modification de l'architecture du micro-drain ainsi que de la technique chirurgicale devrait augmenter le taux de succès.

Effects of beta-blockade on energy metabolism following burns.

The purpose of this study was to compare the effects of propranolol administered either by i.v. infusion or by prolonged oral administration (4 days) during the first 3 weeks following burns. The resting metabolic rate (RMR) of 10 non-infected fasting burned patients (TBSA: 28 per cent, range 18-37 per cent) was determined four times consecutively by indirect calorimetry (open circuit hood system) following: (1) i.v. physiological saline; (2) i.v. propranolol infusion (2 micrograms/kg/min following a bolus of 80 micrograms/kg); (3) oral propranolol (40 mg q.i.d. during 4 +/- 1 days); and (4) in control patients. All patients showed large increases in both RMR (144 +/- 2 per cent of reference values) and in urinary catecholamine excretion (three to four times as compared to control values). The infusion of propranolol induced a significant decrease in RMR to 135 +/- 2 per cent and oral propranolol to 129 +/- 3 per cent of reference values. A decrease in lipid oxidation but no change in carbohydrate and protein oxidation were observed during propranolol administration. It is concluded that the decrease in RMR induced by propranolol was not influenced by the route of administration. The magnitude of the decrease in energy expenditure suggests that beta-adrenergic hyperactivity represents only one of the mediators of the hypermetabolic response to burn injury.

Totally implantable robot to treat chronic atrial fibrillation

Chronic atrial fibrillation affects millions of people worldwide. Its surgical treatment often fails to restore the transport function of the atrium. This study first introduces the concept of an atrial assist device (AAD) to restore the pump function of the atrium. The AAD is developed to be totally implantable in the human body with a transcutaneous energy transfer system to recharge the implanted battery. The ADD consists of a motorless pump based on artificial muscle technology, positioned on the external surface of the atrium to compress it and restore its muscular activity. A bench model reproduces the function of a fibrillating atrium to assess the circulatory support that this pump can provide. Atripump (Nanopowers SA, Switzerland) is a dome-shaped silicone-coated nitinol actuator 5 mm high, sutured on the external surface of the atrium. A pacemaker-like control unit drives the actuator that compresses the atrium, providing the mechanical support to the blood circulation. Electrical characteristics: the system is composed of one actuator that needs a minimal tension of 15 V and has a maximum current of 1.5 A with a 50% duty cycle. The implantable rechargeable battery is made of a cell having the following specifications: nominal tension of a cell: 4.1 V, tension after 90% of discharge: 3.5 V, nominal capacity of a cell: 163 mA h. The bench model consists of an open circuit made of latex bladder 60 mm in diameter filled with water. The bladder is connected to a vertically positioned tube that is filled to different levels, reproducing changes in cardiac preload. The Atripump is placed on the outer surface of the bladder. Pressure, volume and temperature changes were recorded. The contraction rate was 1 Hz with a power supply of 12 V, 400 mA for 200 ms. Preload ranged from 15 to 21 cm H(2)O. Maximal silicone membrane temperature was 55 degrees C and maximal temperature of the liquid environment was 35 degrees C. The pump produced a maximal work of 16 x 10(-3) J. Maximal volume pumped was 492 ml min(-1). This artificial muscle pump is compact, follows the Starling law and reproduces the hemodynamic performances of a normal atrium. It could represent a new tool to restore the atrial kick in persistent atrial fibrillation.