Context. Understanding stellar activity in solar-type stars is crucial for the physics of stellar atmospheres as well as for ongoing exoplanet programmes. Aims. We aim to test how well we understand ...stellar activity using our own star, the Sun, as a test case. Methods. We performed a detailed study of the main optical activity indicators (Ca II H & K, Balmer lines, Na I D1 D2, and He I D3) measured for the Sun using the data provided by the HARPS-N solar-telescope feed at the Telescopio Nazionale Galileo. We made use of periodogram analyses to study solar rotation, and we used the pool variance technique to study the temporal evolution of active regions. The correlations between the different activity indicators as well as the correlations between activity indexes and the derived parameters from the cross-correlation technique are analysed. We also study the temporal evolution of these correlations and their possible relationship with indicators of inhomogeneities in the solar photosphere like sunspot number or radio flux values. Results. The value of the solar rotation period is found in all the activity indicators, with the only exception being Hδ. The derived values vary from 26.29 days (Hγ line) to 31.23 days (He I). From an analysis of sliding periodograms we find that in most of the activity indicators the spectral power is split into several “bands” of periods around 26 and 30 days. They might be explained by the migration of active regions between the equator and a latitude of ∼30°, spot evolution, or a combination of both effects. A typical lifetime of active regions of approximately ten rotation periods is inferred from the pooled variance diagrams, which is in agreement with previous works. We find that Hα, Hβ, Hγ, Hϵ, and He I show a significant correlation with the S index. Significant correlations between the contrast, bisector span, and the heliocentric radial velocity with the activity indexes are also found. We show that the full width at half maximum, the bisector, and the disc-integrated magnetic field correlate with the radial velocity variations. The correlation of the S index and Hα changes with time, increasing with larger sun spot numbers and solar irradiance. A similar tendency with the S index and radial velocity correlation is also present in the data. Conclusions. Our results are consistent with a scenario in which higher activity favours the correlation between the S index and the Hα activity indicators and between the S index and radial velocity variations.
Biofuels derived from microalgae is an emerging technology that can supply fuel demand and alleviate greenhouse gas emissions. However, exclusively producing biofuels from microalgae remains to be ...commercially unsustainable because of its high investment and operating costs. A promising opportunity to address this are algal bio-refineries. Nonetheless, there is still a need to verify the environmental sustainability of this system along its entire process chain, from raw material acquisition to end-of-life. This study utilizes a life-cycle perspective approach to assess the sustainability of the algal bio-refinery and developed environmental impact prediction model using artificial intelligence, particularly adaptive neuro fuzzy inference system. Results will indicate the environmental impacts of a bio-refinery system identifying its major hotspots on different environmental impact categories. Results show that in the investigated proposed algal bio-refinery, the transesterification process had a huge contribution on the overall environmental impact having over 51.5 % of the total weight. In addition, ANFIS results showed the correlation of input parameters with respect to the environmental impact of the system. The model also indicated that there is a perfect correlation between the two parameters. The model and its accuracy should be further validated with the use of real data.
In this work we demonstrate optical trapping and manipulation of microparticles suspended in water due to laser-induced convection currents. Convection currents are generated due to laser light ...absorption in an hydrogenated amorphous silicon (a:Si-H) thin film. The particles are dragged towards the beam's center by the convection currents (Stokes drag force) allowing trapping with powers as low as 0.8 mW. However, for powers >3 mW trapped particles form a ring around the beam due to two competing forces: Stokes drag and thermo-photophoretic forces. Additionally, we show that dynamic beam shaping can be used to trap and manipulate multiple particles by photophotophoresis without the need of lithographically created resistive heaters.
•Methylene blue and rose bengal significantly inhibit fungi grow on strains tested.•Three repetitive irradiations improve photodynamic inactivation vs single one.•The method proposed reduces ...photosensitizer and energy density requirements.•The technique is less invasive and could reduce possible side effects.
We compared the effectiveness of a single irradiation vs repetitive irradiation of light, for in vitro photodynamic inactivation (PDI) of Candida albicans and Trichophyton mentagrophytes, by using methylene blue (MB) and rose bengal (RB) as photosensitizers (PS).
MB from 5 to 60 μM and RB from 0.5 to 10 μM, with energy densities from 10 to 60 J/cm2, were tested in C. albicans. We further optimize the PDI by reducing the light energy density and PS concentration for the single irradiation experiments by using repetitive doses (two and three times). MB was tested in C. albicans and T. mentagrophytes, and RB was tested in C. albicans.
MB-PDI and RB-PDI in C. albicans significantly reduced the number of colony-forming units per milliliter (CFU/mL) when compared to the control groups. Using a single irradiation, over 99% growth inhibition of C. albicans was obtained with MB at 20 μM–60 J/cm2, and with RB at 1 μM–30 J/cm2 and 5 μM–10 J/cm2. With repetitive doses, similar results were obtained by reducing several times the light energy density and the PS concentration for C. albicans and T. mentagrophytes.
The results showed that RB was more effective than MB for C. albicans inactivation. In addition, it is possible to significantly reduce the amount of PS and light energy density requirements by using repetitive irradiations in both genera tested. It makes the technique less invasive and could reduce the side effects in people extremely sensitive to the PS or the light.
Abstract Background Stem cell–based therapy has emerged as a potential therapy in acute myocardial infarction (AMI). Although various approaches have been studied, intracoronary injection of bone ...marrow autologous mononuclear cells (BMMC) and the ability of granulocyte colony-stimulating factor (G-CSF) to mobilize endogenous cells have attracted the most attention. Objectives This study compares, for the first time, the efficacy of BMMC injection, G-CSF mobilization, and the combination of both with standard treatment. Methods On Day 1 after primary percutaneous coronary intervention, 120 patients were randomized to a 1) intracoronary BMMC injection; 2) mobilization with G-CSF; 3) both (BMMC injection plus G-CSF); or 4) conventional treatment (control group). G-CSF, 10 μg/kg/day subcutaneously, was started Day 1 and maintained for 5 days. BMMC injection was performed on Days 3 to 5. Our primary endpoint was absolute change in 12-month left ventricular ejection fraction (LVEF) and left ventricular end-systolic volume (LVESV) relative to baseline measured by cardiac magnetic resonance. Results The mean change in LVEF between baseline and follow-up for all patients was 4 ± 6% (p = 0.006). Change in LVEF and LVESV over time did not differ significantly among the 4 groups. Patients actively treated with any stem cell approach showed similar changes in LVEF and LVESV versus control subjects, with a small but significant reduction in infarct area (p = 0.038). Conclusions In our study, 3 different bone marrow–derived stem cell approaches in AMI did not result in improvement of LVEF or volumes compared with standard AMI care (Trial of Hematopoietic Stem Cells in Acute Myocardial Infarction TECAM; NCT00984178 )
Abstract Purpose Most data regarding infective endocarditis (IE) after transcatheter aortic valve implantation (TAVI) comes from TAVI registries, rather than IE dedicated cohorts. The objective of ...our study was to compare the clinical and microbiological profile, imaging features and outcomes of patients with IE after SAVR with a biological prosthetic valve (IE-SAVR) and IE after TAVI (IE-TAVI) from 6 centres with an Endocarditis Team (ET) and broad experience in IE. Methods Retrospective analysis of prospectively collected data. From the time of first TAVI implantation in each centre to March 2021, all consecutive patients admitted for IE-SAVR or IE-TAVI were prospectively enrolled. Follow-up was monitored during admission and at 12 months after discharge. Results 169 patients with IE-SAVR and 41 with IE-TAVI were analysed. Early episodes were more frequent among IE-TAVI. Clinical course during hospitalization was similar in both groups, except for a higher incidence of atrioventricular block in IE-SAVR. The most frequently causative microorganisms were S. epidermidis , Enterococcus spp. and S. aureus in both groups. Periannular complications were more frequent in IE-SAVR. Cardiac surgery was performed in 53.6% of IE-SAVR and 7.3% of IE-TAVI (p=0.001), despite up to 54.8% of IE-TAVI patients had an indication. No differences were observed about death during hospitalization (32.7% vs 35.0%), and at 1-year follow-up (41.8% vs 37.5%), regardless of whether the patient underwent surgery or not. Conclusion Patients with IE-TAVI had a higher incidence of early prosthetic valve IE. Compared to IE-SAVR, IE-TAVI patients underwent cardiac surgery much less frequently, despite having surgical indications. However, in-hospital and 1-year mortality rate was similar between both groups.
The aim of this work is to relate the macroscopic evolution of the compression superelastic effect in Cu–Al–Ni shape memory alloy single crystals with the evolution of the microstructure during ...cycling. The analysis has been carried out as a function of the number of cycles, the maximum reached deformation and the kind of induced martensite. Moreover, the new microstructure after mechanical cycling and the evolution of the thermal transformation have been also studied. The presence of two new families of dislocations created by different mechanisms has been observed and the influence of each one on the stress-induced and thermal transformations has been analyzed. In the samples where both kinds of dislocations are present at the same time, the observed behaviour is a combination of their effects in proportion to their density.
IntroductionTranscatheter aortic valve implantation (TAVI) as a treatment in severe aortic stenosis (AS) is an excellent alternative to conventional surgical replacement. However, long-term outcomes ...are not benign. Renin-angiotensin system (RAS) blockade has shown benefit in terms of adverse remodelling in severe AS and after surgical replacement.Methods and analysisThe RAS blockade after TAVI (RASTAVI) trial aims to detect if there is a benefit in clinical outcomes and ventricular remodelling with this therapeutic strategy following the TAVI procedure. The study has been designed as a randomised 1:1 open-label study that will be undertaken in 8 centres including 336 TAVI recipients. All patients will receive the standard treatment. The active treatment group will receive ramipril as well. Randomisation will be done before discharge, after signing informed consent. All patients will be followed up for 3 years. A cardiac magnetic resonance will be performed initially and at 1 year to assess ventricular remodelling, defined as ventricular dimensions, ejection fraction, ventricular mass and fibrosis. Recorded events will include cardiac death, admission due to heart failure and stroke. The RASTAVI Study will improve the management of patients after TAVI and may help to increase their quality of life, reduce readmissions and improve long-term survival in this scenario.Ethics and disseminationAll authors and local ethics committees have approved the study design. All patients will provide informed consent. Results will be published irrespective of whether the findings are positive or negative.Trial registration number NCT03201185.
Stress-induced martensite nucleation and further growing, in Cu–Al–Ni shape memory alloys, have been studied during in situ superelastic tests in the transmission electron microscope. Two kinds of ...martensite,
β
3
′
and
γ
3
′
, are induced and can coexist under stress, both exhibiting in a high density of stacking faults. The interface plane and the orientation relationships between the different variants of such martensites have been determined, and the atomic configurations of the lattices across the interface have been described. Finally, in light of the results, selection rules for the stress-induced promoted martensites at the nano-scale have been established, being determined by the shear direction and the basal plane of the martensite lattice.
•Size-effect on mechanical damping at the nanoscale in shape memory alloys.•Comparison of superelastic damping in ternary and quaternary shape memory alloys.•Loss factor measured during ...nano-compression superelastic cycles.•Damping in micro/nano pillars of Cu-based SMA to improve MEMS reliability.
Superelasticity is a characteristic thermomechanical property in shape memory alloys (SMA), which is due to a reversible stress-induced martensitic transformation. Nano-compression experiments made possible the study of this property in Cu–Al–Ni SMA micropillars, showing an outstanding ultra-high mechanical damping capacity reproducible for thousands of cycles and reliable over the years. This scenario motivated the present work, where a comparative study of the damping capacity on four copper-based SMA: Cu–Al–Ni, Cu–Al–Be, Cu–Al–Ni–Be and Cu–Al–Ni–Ga is approached. For this purpose, 001 oriented single-crystal micropillars of comparable dimensions (around 1 µm in diameter) were milled by focused ion beam technique. All micropillars were cycled up to two hundred superelastic cycles, exhibiting a remarkable reproducibility. The damping capacity was evaluated through the dimensionless loss factor η, calculated for each superelastic cycle, representing the dissipated energy per cycle and unit of volume. The calculated loss factor was averaged between three micro-pillars of each alloy, obtaining the following results: Cu–Al–Ni η = 0.20 ± 0.01; Cu–Al–Be η = 0.100 ± 0.006; Cu–Al–Ni–Be η = 0.072 ± 0.004 and Cu–Al–Ni–Ga η = 0.042 ± 0.002. These four alloys exhibit an intrinsic superelastic damping capacity and offer a wide loss factor band, which constitutes a reference for engineering, since this kind of micro/nano structures can potentially be integrated not only as sensors and actuators but also as dampers in the design of MEMS to improve their reliability. In addition, the study of the dependence of the superelastic loss factor on the diameter of the pillar was approached in the Cu–Al–Ni–Ga alloy, and here we demonstrate that there is a size effect on damping at the nanoscale.
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