258 research outputs found
Bouncing transient currents and SQUID-like voltage in nano devices at half filling
Nanorings asymmetrically connected to wires show different kinds of quantum
interference phenomena under sudden excitations and in steady current
conditions. Here we contrast the transient current caused by an abrupt bias to
the magnetic effects at constant current. A repulsive impurity can cause charge
build-up in one of the arms and reverse current spikes.
Moreover, it can cause transitions from laminar current flow to vortices, and
also change the chirality of the vortex. The magnetic behavior of these devices
is also very peculiar. Those nano-circuits which consist of an odd number of
atoms behave in a fundamentally different manner compared to those which
consist of an even number of atoms. The circuits having an odd number of sites
connected to long enough symmetric wires are diamagnetic; they display
half-fluxon periodicity induced by many-body symmetry even in the absence of
electron-phonon and electron-electron interactions. In principle one can
operate a new kind of quantum interference device without superconductors.
Since there is no gap and no critical temperature, one predicts qualitatively
the same behavior at and above room temperature, although with a reduced
current. The circuits with even site numbers, on the other hand, are
paramagnetic.Comment: 7 pages, 10 figures, accepted by Phys. Rev.
Physical activity ameliorates cardiovascular health in elderly subjects: the functional role of the Beta adrenergic system.
Aging is a complex process characterized by a gradual decline in organ functional reserves, which eventually reduces the ability to maintain homeostasis. An exquisite feature of elderly subjects, which constitute a growing proportion of the world population, is the high prevalence of cardiovascular disorders, which negatively affect both the quality of life and the life expectancy. It is widely acknowledged that physical activity represents one of the foremost interventions capable in reducing the health burden of cardiovascular disease. Interestingly, the benefits of moderate-intensity physical activity have been established both in young and elderly subjects. Herein we provide a systematic and updated appraisal of the literature exploring the pathophysiological mechanisms evoked by physical activity in the elderly, focusing on the functional role of the β adrenergic system
A Multistep Approach to Deal With Advanced Heart Failure: A Case Report on the Positive Effect of Cardiac Contractility Modulation Therapy on Pulmonary Pressure Measured by CardioMEMS
During the last years, the management of heart failure (HF) made substantial progress, focusing on device-based therapies to meet the demands of this complex syndrome. In this case report, we present a multistep approach to deal with HF. Specifically, we report the first patient subjected to the implantation of both Optimizer Smart(R) (Impulse Dynamics Inc., Marlton, NJ, USA) and CardioMEMS devices. A 72-year-old male patient with HF and reduced ejection fraction (HFrEF) was admitted to our cardiology department in January 2021, following a progressive shortening of the time between hospitalizations for levosimendan infusions. Specifically, the patient was monitored daily by CardioMEMS, and a strategy of levosimendan infusions guided by the device had been adopted. He was also a carrier of MitraClips and cardiac resynchronization therapy defibrillator (CRT-D) and had optimized HF medical therapy. In January 2021, the patient implanted Optimizer Smart(R) device for cardiac contractility modulation (CCM) therapy because of poor response to therapy and elevated pulmonary artery pressure (PAP). CCM significantly reduced PAP values following discharge (systolic PAP 33.67 & PLUSMN; 2.92 vs. 40.6 & PLUSMN; 3.37 mmHg, diastolic PAP 14.5 & PLUSMN; 2.01 vs. 22.5 & PLUSMN; 2.53 mmHg, mean PAP 22.87 & PLUSMN; 2.20 vs. 30.9 & PLUSMN; 2.99 mmHg, HR 60.93 & PLUSMN; 1.53 vs. 80.83 & PLUSMN; 3.66 bpm; p < 0.0001), with persisting effect at 9 months. The usefulness of CCM is objectively demonstrated for the first time by continuous invasive monitoring of PAP by CardioMEMS, which can suggest the correct timing for CCM implantation
It is easy to see, but it is better to foresee: a case report on the favourable alliance between CardioMEMS and levosimendan
Abstract
Background
In the past years, different devices have been investigated to help in identifying early decompensation events in patients with heart failure (HF) and reduced ejection fraction (EF), reducing hospital admissions. In this report, we present the first patient experience with levosimendan infusion led by CardioMEMS.
Case summary
A 68-year-old man with HF and reduced EF with more than 20 hospitalizations for exacerbation of HF was enrolled in our HF Clinic from October 2017. Echocardiogram showed a dilated left ventricle with severely reduced EF (29%) and increased pulmonary artery systolic pressure (40 mmHg). From October 2017 to May 2019, the patient went through numerous hospitalizations, despite optimal medical therapy; subsequently, was adopted a strategy of levosimendan infusions guided by CardioMEMS. Levosimendan infusions improved haemodynamic and pressure profiles. The patient was monitored daily by CardioMEMS, and from June to December 2019, he had only two hospitalizations scheduled for levosimendan infusion and none for HF exacerbation.
Discussion
Our case supports the combination of CardioMEMS and levosimendan for the optimal management of patients with advanced HF. These results further strengthen the development of a randomized clinical trial to demonstrate the clinical usefulness of this device in combination with the levosimendan infusion programme in advanced HF patients
Growth inhibition of human hepatocellular carcinoma cells by overexpression of G protein-coupled receptor kinase 2
Human-Centered Design of a Collaborative Robotic System for the Shoe-Polishing Process
Demand for automated processes in the manufacturing industry is now shifting toward flexible, human-centered systems that combine productivity and high product quality, thus combining the advantages of automated and robotic systems with the high-value-added skills of operators and craftsmen. This trend is even more crucial for small and medium-sized enterprises operating in the “Made in Italy” fashion industry. The paper presents the study, simulation, and preliminary testing of a collaborative robotic system for shoe polishing that can reduce manual labor by limiting it to the finishing stage of the process, where the aesthetic result is fully achieved, with a benefit also in terms of ergonomics for the operator. The influence of process parameters and design solutions are discussed by presenting preliminary test results and providing hints for future developments
Monitoring of coastal dunes habitats in Tuscany through the “MONITO-RARE” project
“MONITO-RARE” is a project involving Tuscany Region and Universities of Firenze, Siena and Pisa, aimed to improve the knowledge and develop monitoring methodologies for species and habitats included in Natura 2000 Network and considered of community interest, according to Art. 11 and Art. 17 of the Directive
92/43/EEC. Among the habitat of interest (Annex I), coastal sand dune is one of the most threatened by multiple human pressures (1, 2), such as pollution, coastal erosion, effects of global warming, farming practices, urban development, and pressure from tourism (3). As part of this project, was carried out a first year of monitoring of dunal habitats (Natura 200 code 2110, 2120, 2210, 2230, 2240, 2250* and 2260) in five SACs (Special Areas of Conservation) in order to cover different latitudes of Tuscany coast (“Dune litoranee di Torre del Lago/Selva Pisana”, “Tombolo da Castiglion della Pescaia a Marina di Grosseto”, “Dune costiere del Parco dell’Uccellina” and “Duna del Lago di Burano”). The coastal areas to the north and south of Arno basin are very different by climatic, geomorphologic (erosion) and anthropic factors. The northern coast is twice rainy as the southern one. Nevertheless, sand dune habitats are distributed in a fine scale mosaic, not distinguishable through aerial photos and maps. For this reason, we opted for a stratified sampling in three EUNIS habitat types (B1.3, shifting coastal dunes; B1.4, coastal stable dune grassland; B1.6, coastal dune scrub) for psammophilous
vegetation. According to Sperandii et al. (4), we recorded these communities by 262 random plots of 2 x 2 m surface in which were surveyed pressures and threats, floristic composition and an estimate of abundance using a percentage cover scale ranging from 1 to 10. Our sampling is congruent with RanVegDunes (GIVD ID EU-IT-020), the first Italian database gathering standardized, randomly-sampled vegetation data in coastal dune environments. We detected significative differences in abundance and species composition between EUNIS habitat types, between SACs, and between habitat types within SACs. In particular, our data shows particular differences between communities of north and south of Tuscany: the northern SACs to Serchio river are heavily impacted by the presence of mass tourism, with bathing establishments, roads and human trampling. From
these evidences can be deduced that trails installed within the DUNETOSCA Life Projects and aimed to reduction of tourism impact may be insufficient to reduce anthropic pressures in those contexts and adequate conservation strategies are required.
1) EEA (1999) State and pressures of the marine and coastal Mediterranean Environment. Environmental Issues Series, No. 5, European Environment Agency, Copenhagen
2) Barcelona Convention, Athens (2012) UNEP/MAP 2012. State of the Mediterranean Marine and Coastal Environment https://wedocs.unep.org/bitstream/handle/20.500.11822/364/sommcer_eng.pdf?sequence=4&isAllowed=y
3) Ciccarelli D. (2014) Environmental Management 54, 194–204
4) Sperandii M.G., Prisco I., Stanisci A., Acosta A.T.R. (2017) Phytocoenologia 47, 231–23
High density lipoprotein cholesterol increasing therapy: the unmet cardiovascular need
Despite aggressive strategies are now available to reduce LDL-cholesterol, the risk of cardiovascular events in patients with coronary artery disease remains substantial. Several preclinical and clinical studies have shown that drug therapy ultimately leads to a regression of the angiographic lesions but also results in a reduction in cardiovascular events. The dramatic failure of clinical trials evaluating the cholesterol ester transfer protein (CEPT) inhibitors, torcetrapib and dalcetrapib, has led to considerable doubt about the value of the current strategy to raise high-density lipoprotein cholesterol (HDL-C) as a treatment for cardiovascular disease. These clinical results, as well as animal studies, have revealed the complexity of HDL metabolism, assessing a more important role of functional quality compared to circulating quantity of HDL. As a result, HDL-based therapeutic interventions that maintain or enhance HDL functionality, such as improving its main property, the reverse cholesterol transport, require closer investigation. In this review, we will discuss HDL metabolism and function, clinical-trial data available for HDL-raising agents, and potential strategies for future HDL-based therapies
Enhanced GRK2 expression and desensitization of betaAR vasodilatation in hypertensive patients.
Increased levels of G protein coupled receptor kinase GRK2 appear to participate in hypertension presumably through the desensitization of beta adrenergic receptors (betaARs) that mediate vasodilatation. There are contrasting data on the occurrence of betaAR desensitization in the vasculature, we therefore investigated betaAR vasodilatation and desensitization in normotensives and in hypertensive humans. In blood lymphocytes, we assessed betaAR signaling and GRK2 expression and found betaAR signaling alterations and, consistent with desensitization, ncreased GRK2 levels in hypertensives. We studied in vivo vasodilatation to the betaAR agonist isoproterenol (ISO) injected in the brachia artery in control conditions and during the concomitant infusion of heparin, a known in vitro nonspecific GRK inhibitor. ISO induced a dose-dependent vasorelaxation that was attenuated in hypertensives indicating a loss of betaAR signaling. Intra-arterial infusion of heparin nhibited lymphocyte GRK2 activity and prevented desensitization of betaAR vasodilatation in normotensives. In hypertensives, heparin restored vasodilatation to ISO, to levels observed in normotensives. Our results suggest that betaAR desensitization does indeed occur at the vascular levels in vivo, and that heparin by acting as a GRK inhibitor prevents this in normotensives and restores impaired betaAR vasodilation in hypertensives. We conclude that desensitization participates to impaired betaAR vasodilation in hypertension
A polymorphism within the promoter of the dopamine receptor D1 (DRD1 -48A7G) associates with impaired kidney function in white hypertensive patients
Dopamine DRD1 receptor regulates renal function and vascular resistance. It plays a role in the pathogenesis of hypertension in animal models. In humans, the DRD1 gene presents a A-48G polymorphism associated to hypertension in a Japanese population. To explore the role of this polymorphism on blood pressure and renal function in Caucasian hypertensive patients (H), we evaluated the allele frequencies in a populations of 697 H and 100 blood volunteers, and found no difference in the distribution of the alleles between the two groups (AA;AG;GG: 13%;50%;37%; and 12%; 51%;36% respectively). In H, we found a significant difference between AA and GG in serum creatinine (AA: 1.06±.08 mg/dl; GG:0.97±0.02 mg/dl, p<0.03). Treatment restored serum creatinine at levels comparable between genotypes (AA: 0.99±0.03 mg/dl; GG: 0.94±0.02 mg/dl, n.s.). To replicate the finding, in a case control study of 8 AA and 7 GG hypertensive patients matched for age, sex and body mass index, in pharmacological wash out for 30 days, we evaluated serum (Creatinine, Na, Uric Acid, Urea) and urinary (volume/24h, protein/24h, creatinine clearance/24h) biochemistry and renal hemodynamic assessed by ultrasound. Once again, the AA group showed higher serum creatinine, Na, Uric acid and urea, reduced creatinine clearance and a higher level of urinary protein excretion. These changes occurred while no differences were observed in diuresis and renal vascular resistances. In conclusions, the DRD1 A-48G polymorphism identifies a class of H that is prone to hypertension related kidney alterations
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