294 research outputs found
Quantum advantage in the charging process of Sachdev-Ye-Kitaev batteries
The exactly-solvable Sachdev-Ye-Kitaev (SYK) model has recently received
considerable attention in both condensed matter and high energy physics because
it describes quantum matter without quasiparticles, while being at the same
time the holographic dual of a quantum black hole. In this Letter, we examine
SYK-based charging protocols of quantum batteries with N quantum cells.
Extensive numerical calculations based on exact diagonalization for N up to 16
strongly suggest that the optimal charging power of our SYK quantum batteries
displays a super-extensive scaling with N that stems from genuine quantum
mechanical effects. While the complexity of the nonequilibrium SYK problem
involved in the charging dynamics prevents us from an analytical proof, we
believe that this Letter offers the first (to the best of our knowledge) strong
numerical evidence of a quantum advantage occurring due to the
maximally-entangling underlying quantum dynamics.Comment: 12 pages, 7 figures. Final versio
Combining echo and natriuretic peptides to guide heart failure care in the outpatient setting: a position paper
BACKGROUND: Chronic heart failure (HF) is a relevant and growing public health problem. Although the prognosis has recently improved, it remains a lethal disease, with a mortality that equals or exceeds that of many malignancies. Furthermore, chronic HF is costly, representing a large and growing drain on healthcare resources.
METHODS: This narrative review is based on the material searched for and obtained via PubMed up to May 2017. The search terms we used were: "heart failure, echocardiography, natriuretic peptides" in combination with "treatment, biomarkers, guidelines".
RESULTS: Particularly, hospitalization contributes to the greatest proportion of expenditure. Recent studies have supported the value of natriuretic peptides (NPs) and Doppler echocardiographic biomarkers of increased left ventricular (LV) filling pressures or pulmonary congestion as tools to scrutinize patients with impending clinically overt HF. Therefore, combination of pulsed-wave tissue and blood-flow Doppler with NPs appears valuable in guiding HF management in the outpatient setting. In as much as both the echo and the plasma levels of NPs may reflect the presence of fluid overload and elevations of LV filling pressures, integrating NP and echocardiographic biomarkers with clinical findings may help the cardiologist to identify high-risk patients, i.e. to recognize whether a patient is stable or the condition is likely to evolve into decompensated HF, to optimize treatment, to improve the prognosis and to reduce re-hospitalization.
CONCLUSION: we discussed the rationale and the clinical significance of combining follow-up echo and NP assessment to guide management of ambulatory patients with chronic HF
Cardiovascular effects of antimuscarinic agents and beta3-adrenergic receptor agonist for the treatment of overactive bladder
Overactive bladder (OAB) syndrome is common in the general population, particularly in elderly patients. Antimuscarinic drugs (AMs) are considered the mainstay pharmaceutical treatment of OAB whereas \u3b23-adrenoceptor agonists, such as mirabegron, represent a good alternative. Owing to the important role of muscarinic and \u3b23 receptors in cardiovascular (CV) tissue and to the fact that OAB patients often have CV comorbidities, the safety-profile of these drugs constitute an important challenge. Area covered: The aim of this review is to evaluate the CV effects of AMs and mirabegron in OAB. A systematic literature search from inception until December 2017 was performed on PubMed and Medline. Expert opinion: AMs are generally considered to have good CV safety profile but, however, they may cause undesirable adverse events, such as dry mouth, constipation. CV AEs are rare but noteworthy, the most common CV consequences related to the use of these drugs are constituted by an increase in HR and QT interval. Mirabegron has similar efficacy and tolerability to AMs but causes less adverse events, with either modest hypertension and modest increase in HR (<5 bpm) being the most commonly reported
Enhanced expression of PACAP and of its high affinity receptor (PAC1) in the hippocampus and cerebral cortex of dopamine D3 knockout mice
Dopamine (DA) D3 receptor (D3R) is a pre-synaptic autoreceptor whose main role is to modulate DA release through a negative feedback regulatory loop. Immunolocalization studies from our research group have previously described that these receptors, despite being relatively low expressed in the central nervous system (CNS), may still be detected in less discreet brain regions normally associated to memory function, including the hippocampus and the cerebral cortex (1). Consistent with these findings, genetic deletion of the D3R in mice (D3R-/-) has been shown to have profound repercussions on the formation of new memories, especially fear associative memories (2). While it is now well-accepted that such pro-cognitive effects in these mice are presumably due to the increased DA bioavailability caused by the lack of autoreceptor function, it still remains to be established if there are molecular determinants directly or indirectly involved in ameliorating this specific type of associative learning. Pituitary adenylate cyclase-activating polypeptide (PACAP) is an endogenous peptide which is gaining scientific relevance because of its prominent “cognitive enhancer” function and the recent developments suggesting its active participation in the acquisition and consolidation of fear memories (3, 4). Based on these evidences, we thought it could have been of scientific relevance to assess whether PACAP expression, as well as that of its binding receptors, are affected in knockout mice showing this peculiar behavioural phenotype. We found that PACAP immunoreactivity (IR) was present at low levels in CA1 hippocampal subfield while moderate staining was observed in CA2-CA3 fields and in the dentate gyrus (DG) of wild-type (WT) mice. In sharp contrast, PACAP-IR was remarkably increased in all CA subfields, and particularly in CA1, CA3 and the DG regions of D3R-/- mice. Regarding the cerebral cortex (CX), PACAP expression was restricted to the V cortical layer in WT mice, whereas in D3R-/- mice, stained neurons were apparent both in the IV, V and VI cortical layers, with an overall increased staining score. In line with these findings, the expression of the PACAP-preferring PAC1 receptor, which was detectable only at moderate levels in the CA2 subfield of WTs, was enhanced in both CA2 and CA3 of D3R-/- mice. Interestingly, PAC1-IR was already present at moderate levels in the II-III cortical layers of WT mice, but genetic deletion of the D3R caused a remarkable spread of PAC1-stained neurons throughout all cortical layers, with the exception of layer I. We conclude that the absence or blockade of functional D3Rs from the brain enhances both PACAP and PAC1 receptor expression levels in the hippocampus and cerebral cortex. Considering the ameliorative role mediated by PACAP-PAC1 signalling in cognition, we infer that enhanced PACAP peptide and receptor expression may relate to the specific behavioural phenotype of these mice
Nabiximols effect on blood pressure and heart rate in post-stroke patients of a randomized controlled study
Background: Cannabinoids may be useful to treat pain, epilepsy and spasticity, although they may bear an increased risk of cardiovascular events. This study aims to evaluate the cardiovascular safety of nabiximols, a cannabis-based drug, in patients with spasticity following stroke, thus presenting an increased cardiovascular risk.
Methods: This is an ancillary study stemming from the SativexStroke trial: a randomized double-blind, placebo-controlled, crossover study aimed at assessing the effect of nabiximols on post-stroke spasticity. Patients were treated with nabiximols oromucosal spray or placebo and assessed before and after two phases of 1-month duration each. Only the phase with the active treatment was considered for each patient who completed the study. The average values of blood pressure (diastolic, systolic, differential) and heart rate from the first 5 days of the phase (lowest nabiximols dosage) were compared to the average values recorded during the last 5 days at the end of the phase (highest nabiximols dosage). Baseline comparisons between gender, stroke type and affected side and correlation between age and blood pressure and heart rate were performed. The study was registered with the EudraCT number 2016-001034-10.
Results: Thirty-four patients completed the study and were included in the analysis. Thirty-one were taking antihypertensive drugs and, among these, 12 were taking beta-blockers. During the study, no arrhythmic events were recorded, blood pressure and heart rate did not show pathological fluctuations, and no cardiovascular or cerebrovascular events occurred. At baseline blood pressure and heart rate were comparable concerning gender, stroke type and affected side. A significant direct correlation emerged between differential blood pressure and age and an inverse correlation between diastolic blood pressure and age. No correlation emerged between systolic blood pressure or heart rate and age. Blood pressure and heart rate did not change during nabiximols treatment compared to the baseline condition.
Conclusion: This ancillary study adds evidence that, in patients who already underwent a cerebrovascular accident, nabiximols does not determine significant blood pressure and heart rate variation or cardiovascular complications. These data support the cardiovascular safety of nabiximols, encouraging more extensive studies involving cannabinoids characterized by slow absorption rates
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