Aims. We present high-resolution and high-quality UVES spectroscopic data of the metal-poor double-lined spectroscopic binary CS 22876–032 (Fe/H approximately −3.7 dex). Our goal is to derive the ...6Li/7Li isotopic ratio by analysing the Li I λ 670.8 nm doublet. Methods. We co-added all 28 useful spectra normalised and corrected for radial velocity to the rest frame of the primary star. We fitted the Li profile with a grid of the 3D non-local thermodynamic equilibrium (NLTE) synthetic spectra to take into account the line profile asymmetries induced by stellar convection, and performed Monte Carlo simulations to evaluate the uncertainty of the fit of the Li line profile. Results. We checked that the veiling factor does not affect the derived isotopic ratio, 6 Li/7Li, and only modifies the Li abundance, A(Li), by about 0.15 dex. The best fit of the Li profile of the primary star provides A(Li) = 2.17 ± 0.01 dex and 6 Li/7Li = 8−5+2 $\,{=}\,8^{+2}_{-5}$ = 8−5+2 % at 68% confidence level. In addition, we improved the Li abundance of the secondary star at A(Li) = 1.55 ± 0.04 dex, which is about 0.6 dex lower than that of the primary star. Conclusions. The analysis of the Li profile of the primary star is consistent with no detection of 6 Li and provides an upper limit to the isotopic ratio of 6 Li/7Li < 10% at this very low metallicity, about 0.5 dex lower in metallicity than previous attempts for detection of 6 Li in extremely metal poor stars. These results do not solve or worsen the cosmological 7 Li problem, nor do they support the need for non-standard 6Li production in the early Universe.
In Parkinson's disease, striatal dopamine depletion produces profound alterations in the neural activity of the cortico-basal ganglia motor loop, leading to dysfunctional motor output and ...parkinsonism. A key regulator of motor output is the balance between excitation and inhibition in the primary motor cortex, which can be assessed in humans with transcranial magnetic stimulation techniques. Despite decades of research, the functional state of cortical inhibition in Parkinson's disease remains uncertain. Towards resolving this issue, we applied paired-pulse transcranial magnetic stimulation protocols in 166 patients with Parkinson's disease (57 levodopa-naïve, 50 non-dyskinetic, 59 dyskinetic) and 40 healthy controls (age-matched with the levodopa-naïve group). All patients were studied OFF medication. All analyses were performed with fully automatic procedures to avoid confirmation bias, and we systematically considered and excluded several potential confounding factors such as age, gender, resting motor threshold, EMG background activity and amplitude of the motor evoked potential elicited by the single-pulse test stimuli. Our results show that short-interval intracortical inhibition is decreased in Parkinson's disease compared to controls. This reduction of intracortical inhibition was obtained with relatively low-intensity conditioning stimuli (80% of the resting motor threshold) and was not associated with any significant increase in short-interval intracortical facilitation or intracortical facilitation with the same low-intensity conditioning stimuli, supporting the involvement of cortical inhibitory circuits. Short-interval intracortical inhibition was similarly reduced in levodopa-naïve, non-dyskinetic and dyskinetic patients. Importantly, intracortical inhibition was reduced compared to control subjects also on the less affected side (n = 145), even in de novo drug-naïve patients in whom the less affected side was minimally symptomatic (lateralized Unified Parkinson's Disease Rating Scale part III = 0 or 1, n = 23). These results suggest that cortical disinhibition is a very early, possibly prodromal feature of Parkinson's disease.
An experimental study of heat and mass transfer on a tube bank under frost formation conditions was conducted using a closed-loop wind tunnel. The tube bank was exposed to a controlled environment; ...surface temperature from −14∘C to −8∘C, relative humidity from 50% to 90%, air dry bulb temperature from 1 °C to 11 °C, average air velocity from 0.3 ms−1 to 1.0 ms−1, and Reynolds number from 518 to 1719. The results showed a non-uniform frost growth due to the air stream characteristics. When the Reynolds number increases a more uniform pattern becomes noticeable. The frost growth is more uniform on the last tube than on the first one, due to the aerodynamic differences. Sensible heat transfer has a greater impact on the total heat transfer, compared to latent heat transfer effect. The higher the frost layer growth the lower the frost deposition rate on the tubes.
•Occurrence of mycotoxins in feeds made from plants and animal by-products.•Carry-over from feeds to fillets of Atlantic salmon and gilthead sea bream.•None observed mycotoxins carry-over from feed ...to edible parts of fish.•Discussion of the use of plant and animal ingredients in fish feeding.•Satisfactory limits of quantification below LMR established by EU regulations.
Plant ingredients and processed animal proteins (PAP) are suitable alternative feedstuffs for fish feeds in aquaculture practice, although their use can introduce contaminants that are not previously associated with marine salmon and gilthead sea bream farming. Mycotoxins are well known natural contaminants in plant feed material, although they also could be present on PAPs after fungi growth during storage. The present study surveyed commercially available plant ingredients (19) and PAP (19) for a wide range of mycotoxins (18) according to the EU regulations. PAP showed only minor levels of ochratoxin A and fumonisin B1 and the mycotoxin carry-over from feeds to fillets of farmed Atlantic salmon and gilthead sea bream (two main species of European aquaculture) was performed with plant ingredient based diets. Deoxynivalenol was the most prevalent mycotoxin in wheat, wheat gluten and corn gluten cereals with levels ranging from 17 to 814 and μgkg−1, followed by fumonisins in corn products (range 11.1–4901μgkg−1 for fumonisin B1+B2+B3). Overall mycotoxin levels in fish feeds reflected the feed ingredient composition and the level of contaminant in each feed ingredient. In all cases the studied ingredients and feeds showed levels of mycotoxins below maximum residue limits established by the Commission Recommendation 2006/576/EC. Following these guidelines no mycotoxin carry-over was found from feeds to edible fillets of salmonids and a typically marine fish, such as gilthead sea bream. As far we know, this is the first report of mycotoxin surveillance in farmed fish species.
•Rail and wheel materials from different standards were tested.•Wear maps of different standards were displayed.•In this study, the sliding speed is the most influencing parameter.
Wheel and rail ...materials are exposed to a large number of factors that affect their wear-resistant performance such as, large contact pressures, sliding speeds, high temperatures, material degradation by natural and artificial contaminants, etc. This directly affects the maintenance operations, so, an accurate wear prediction is required. Wear maps are an important tool to predict and identify wear regimes that impact maintenance schedules and consequently cost reduction.
This work aimed to develop wear maps for a 115RE rail material and an ER8 wheel material, which are materials used in railways systems in Mexico, as well as identify the wear regimes and wear mechanisms replicating the wheel-rail interface conditions.
Metallographic analysis and hardness tests were carried out for both materials. Wear tests were carried out by using a pin-on-disk tribometer. The resulting wear maps showed that a catastrophic wear regime occurs at medium sliding speed and low contact pressure values for the wheel. On the other hand, for rail, catastrophic wear regime occurs at high sliding speed and low contact pressure values.
•SERS substrates were obtained through EPD of silver nanoparticles on copper plates.•The SERS substrates obtained at 300mV allowed the detection of 10−6M R6G.•The analytical enhancement factors of ...the SERS substrates are about 103–104.
Surface-enhanced Raman scattering (SERS) substrates were obtained by electrophoretic deposition (EPD) of silver nanoparticles with different morphologies. The silver nanoparticles were prepared by chemical methods in aqueous dispersion. Silver nanospheres, triangular nanoprisms and nanodisks were deposited on vertically aligned copper plates in an electrophoretic cell. The silver nanoparticles were deposited using a constant applied voltage of 300mV, 600mV and 900mV for 24h. Silver thin films porosity can be tunable varying the strength of the applied electric field. The resulting high porosity provides a high surface area for adsorption of analyte molecules, which increases the number of molecules available for Raman analysis. The analytical enhancement factors of the silver SERS substrates prepared at 300mV were determined using rhodamine 6G (R6G) as analyte. The analytical enhancement factors of the fabricated SERS substrates are about 103–104, which are enough to detect analytes at concentrations below 1ppm. This study provides a green, simple, low-cost and large-area methodology for the fabrication of SERS substrates.
Many novel tobacco products have been developed in recent years. Although many may emit lower levels of several toxicants, their risk in the long term remains unclear. We previously published a ...method for the exposure assessment of mixtures that can be used to compare the changes in cumulative exposure to carcinogens among tobacco products. While further developing this method by including more carcinogens or to explore its application to non-cancer endpoints, we encountered a lack of data that are required for better-substantiated conclusions regarding differences in exposure between products. In this special communication, we argue the case for more data on adverse health effects, as well as more data on the composition of the emissions from tobacco products. Such information can be used to identify significant changes in relevance to health using the cumulative exposure method with different products and to substantiate regulatory decisions.
Biomarkers in atrial fibrillation: an overview Vílchez, J. A.; Roldán, V.; Hernández-Romero, D. ...
International journal of clinical practice (Esher),
April 2014, Letnik:
68, Številka:
4
Journal Article
Recenzirano
Summary
Atrial fibrillation (AF) confers a raised risk of stroke and death, and this risk of adverse events is increased by the coexistence of other cardiovascular risk factors. The pathophysiology ...of AF is complex, involving the role of inflammation, structural remodelling with apoptosis, inflammation or fibrosis. These changes confer a prothrombotic or hypercoagulable state in this arrhythmia. Despite being easy to use for decision‐making concerning oral anticoagulant therapy in AF, clinical risk scores used for stratification have shown modest capability in predicting thromboembolic events, and biomarkers may improve our identification of ‘high risk’ patients. Biomarkers, whether measured in the peripheral blood, urine or imaging‐based may improve our knowledge of the pathophysiology of AF. Importantly these biomarkers could help in the assessment of AF prognosis. The aim of this review was to summarise the published data about biomarkers studied in AF, with focus on data from randomised prospective clinical trials and large community‐based cohorts. We will also review the application of these biomarkers to prognosis on the main schemes used to help stratify risk in AF.
Linked Comment: Lip. Int J Clin Pract 2014; 68: 408–9.
There is a lack of information regarding the provision of parental leave for surgical careers. This survey study aims to evaluate the experience of maternity/paternity leave and views on work-life ...balance globally.
A 55-item online survey in 24 languages was distributed via social media as per CHERRIES guideline from February to March 2020. It explored parental leave entitlements, attitude towards leave taking, financial impact, time spent with children and compatibility of parenthood with surgical career.
Of the 1393 (male : female, 514 : 829) respondents from 65 countries, there were 479 medical students, 349 surgical trainees and 513 consultants. Consultants had less than the recommended duration of maternity leave (43.8 versus 29.1 per cent), no paid maternity (8.3 versus 3.2 per cent) or paternity leave (19.3 versus 11.0 per cent) compared with trainees. Females were less likely to have children than males (36.8 versus 45.6 per cent, P = 0.010) and were more often told surgery is incompatible with parenthood (80.2 versus 59.5 per cent, P < 0.001). Males spent less than 20 per cent of their salary on childcare and fewer than 30 hours/week with their children. More than half (59.2 per cent) of medical students did not believe a surgical career allowed work-life balance.
Surgeons across the globe had inadequate parental leave. Significant gender disparity was seen in multiple aspects.
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