Context. Over the past 40 years, helioseismology has been enormously successful in the study of the solar interior. A shortcoming has been the lack of a convincing detection of the solar g modes, ...which are oscillations driven by gravity and are hidden in the deepest part of the solar body – its hydrogen-burning core. The detection of g modes is expected to dramatically improve our ability to model this core, the rotational characteristics of which have, until now, remained unknown. Aims. We present the identification of very low frequency g modes in the asymptotic regime and two important parameters that have long been waited for: the core rotation rate, and the asymptotic equidistant period spacing of these g modes. Methods. The GOLF instrument on board the SOHO space observatory has provided two decades of full-disk helioseismic data. The search for g modes in GOLF measurements has been extremely difficult because of solar and instrumental noise. In the present study, the p modes of the GOLF signal are analyzed differently: we search for possible collective frequency modulations that are produced by periodic changes in the deep solar structure. Such modulations provide access to only very low frequency g modes, thus allowing statistical methods to take advantage of their asymptotic properties. Results. For oscillatory periods in the range between 9 and nearly 48 h, almost 100 g modes of spherical harmonic degree 1 and more than 100 g modes of degree 2 are predicted. They are not observed individually, but when combined, they unambiguously provide their asymptotic period equidistance and rotational splittings, in excellent agreement with the requirements of the asymptotic approximations. When the period equidistance has been measured, all of the individual frequencies of each mode can be determined. Previously, p-mode helioseismology allowed the g-mode period equidistance parameter P0 to be bracketed inside a narrow range, between approximately 34 and 35 min. Here, P0 is measured to be 34 min 01 s, with a 1 s uncertainty. The previously unknown g-mode splittings have now been measured from a non-synodic reference with very high accuracy, and they imply a mean weighted rotation of 1277 ± 10 nHz (9-day period) of their kernels, resulting in a rapid rotation frequency of 1644 ± 23 nHz (period of one week) of the solar core itself, which is a factor 3.8 ± 0.1 faster than the rotation of the radiative envelope. Conclusions. The g modes are known to be the keys to a better understanding of the structure and dynamics of the solar core. Their detection with these precise parameters will certainly stimulate a new era of research in this field.
The development of economically and ecologically viable strategies for superhydrophobization offers a vast variety of interesting applications in self-cleaning surfaces. Examples include packaging ...materials, textiles, outdoor clothing, and microfluidic devices. In this work, we produced superhydrophobic paper by spin-coating a dispersion of nanostructured fluorinated cellulose esters. Modification of cellulose nanocrystals was accomplished using 2H,2H,3H,3H-perfluorononanoyl chloride and 2H,2H,3H,3H-perfluoroundecanoyl chloride, which are well-known for their ability to reduce surface energy. A stable dispersion of nanospherical fluorinated cellulose ester was obtained by using the nanoprecipitation technique. The hydrophobized fluorinated cellulose esters were characterized by both solid- and liquid-state nuclear magnetic resonance, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and contact angle measurements. Further, we investigated the size, shape, and structure morphology of nanostructured fluorinated cellulose esters by dynamic light scattering, scanning electron microscopy, and X-ray diffraction measurements.
Gypsum soils are among the most restrictive and widespread substrates for plant life. Plants living on gypsum are classified as gypsophiles (exclusive to gypsum) and gypsovags (non-exclusive to ...gypsum). The former have been separated into wide and narrow gypsophiles, each with a putative different ecological strategy. Mechanisms displayed by gypsum plants to compete and survive on gypsum are still not fully understood. The aim of this study was to compare the main chemical groups in the leaves of plants with different specificity to gypsum soils and to explore the ability of Fourier transform infrared (FTIR) spectra analyzed with neural network (NN) modelling to discriminate groups of gypsum plants. Leaf samples of 14 species with different specificity to gypsum soils were analysed with FTIR spectroscopy coupled to neural network (NN) modelling. Spectral data were further related to the N, C, S, P, K, Na, Ca, Mg and ash concentrations of samples. The FTIR spectra of the three groups analyzed showed distinct features that enabled their discrimination through NN models. Wide gypsophiles stood out for the strong presence of inorganic compounds in their leaves, particularly gypsum and, in some species, also calcium oxalate crystals. The spectra of gypsovags had less inorganic chemical species, while those of narrow gypsum endemisms had low inorganics but shared with wide gypsophiles the presence of oxalate. Gypsum and calcium oxalate crystals seem to be widespread amongst gypsum specialist plants, possibly as a way to tolerate excess Ca and sulphate. However, other mechanisms such as the accumulation of sulphates in organic molecules are also compatible with plant specialization to gypsum. While gypsovags seem to be stress tolerant plants that tightly regulate the uptake of S and Ca, the ability of narrow gypsum endemisms to accumulate excess Ca as oxalate may indicate their incipient specialization to gypsum.
Artificial light at night (ALAN) is increasing exponentially worldwide, accelerated by the transition to new efficient lighting technologies. However, ALAN and resulting light pollution can cause ...unintended physiological consequences. In vertebrates, production of melatonin—the “hormone of darkness” and a key player in circadian regulation—can be suppressed by ALAN. In this paper, we provide an overview of research on melatonin and ALAN in vertebrates. We discuss how ALAN disrupts natural photic environments, its effect on melatonin and circadian rhythms, and different photoreceptor systems across vertebrate taxa. We then present the results of a systematic review in which we identified studies on melatonin under typical light-polluted conditions in fishes, amphibians, reptiles, birds, and mammals, including humans. Melatonin is suppressed by extremely low light intensities in many vertebrates, ranging from 0.01–0.03 lx for fishes and rodents to 6 lx for sensitive humans. Even lower, wavelength-dependent intensities are implied by some studies and require rigorous testing in ecological contexts. In many studies, melatonin suppression occurs at the minimum light levels tested, and, in better-studied groups, melatonin suppression is reported to occur at lower light levels. We identify major research gaps and conclude that, for most groups, crucial information is lacking. No studies were identified for amphibians and reptiles and long-term impacts of low-level ALAN exposure are unknown. Given the high sensitivity of vertebrate melatonin production to ALAN and the paucity of available information, it is crucial to research impacts of ALAN further in order to inform effective mitigation strategies for human health and the wellbeing and fitness of vertebrates in natural ecosystems.
BAG3 is a multi-domain hub that connects two classes of chaperones, small heat shock proteins (sHSPs) via two isoleucine-proline-valine (IPV) motifs and Hsp70 via a BAG domain. Mutations in either ...the IPV or BAG domain of BAG3 cause a dominant form of myopathy, characterized by protein aggregation in both skeletal and cardiac muscle tissues. Surprisingly, for both disease mutants, impaired chaperone binding is not sufficient to explain disease phenotypes. Recombinant mutants are correctly folded, show unaffected Hsp70 binding but are impaired in stimulating Hsp70-dependent client processing. As a consequence, the mutant BAG3 proteins become the node for a dominant gain of function causing aggregation of itself, Hsp70, Hsp70 clients and tiered interactors within the BAG3 interactome. Importantly, genetic and pharmaceutical interference with Hsp70 binding completely reverses stress-induced protein aggregation for both BAG3 mutations. Thus, the gain of function effects of BAG3 mutants act as Achilles heel of the HSP70 machinery.
Estimation of model accuracy in CASP13 Cheng, Jianlin; Choe, Myong‐Ho; Elofsson, Arne ...
Proteins, structure, function, and bioinformatics,
December 2019, Volume:
87, Issue:
12
Journal Article
Peer reviewed
Open access
Methods to reliably estimate the accuracy of 3D models of proteins are both a fundamental part of most protein folding pipelines and important for reliable identification of the best models when ...multiple pipelines are used. Here, we describe the progress made from CASP12 to CASP13 in the field of estimation of model accuracy (EMA) as seen from the progress of the most successful methods in CASP13. We show small but clear progress, that is, several methods perform better than the best methods from CASP12 when tested on CASP13 EMA targets. Some progress is driven by applying deep learning and residue‐residue contacts to model accuracy prediction. We show that the best EMA methods select better models than the best servers in CASP13, but that there exists a great potential to improve this further. Also, according to the evaluation criteria based on local similarities, such as lDDT and CAD, it is now clear that single model accuracy methods perform relatively better than consensus‐based methods.
Recommendations for physical activity in patients with stable coronary heart disease (CHD) are based on modest evidence.
The authors analyzed the association between self-reported exercise and ...mortality in patients with stable CHD.
A total of 15,486 patients from 39 countries with stable CHD who participated in the STABILITY (Stabilization of Atherosclerotic Plaque by Initiation of Darapladib Therapy) study completed questions at baseline on hours spent each week taking mild, moderate, and vigorous exercise. Associations between the volume of habitual exercise in metabolic equivalents of task hours/week and adverse outcomes during a median follow-up of 3.7 years were evaluated.
A graded decrease in mortality occurred with increased habitual exercise that was steeper at lower compared with higher exercise levels. Doubling exercise volume was associated with lower all-cause mortality (unadjusted hazard ratio HR: 0.82; 95% confidence interval CI: 0.79 to 0.85; adjusting for covariates, HR: 0.90; 95% CI: 0.87 to 0.93). These associations were similar for cardiovascular mortality (unadjusted HR: 0.83; 95% CI: 0.80 to 0.87; adjusted HR: 0.92; 95% CI: 0.88 to 0.96), but myocardial infarction and stroke were not associated with exercise volume after adjusting for covariates. The association between decrease in mortality and greater physical activity was stronger in the subgroup of patients at higher risk estimated by the ABC-CHD (Age, Biomarkers, Clinical–Coronary Heart Disease) risk score (p for interaction = 0.0007).
In patients with stable CHD, more physical activity was associated with lower mortality. The largest benefits occurred between sedentary patient groups and between those with the highest mortality risk.
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Abstract
Aims
More than 50% of patients with heart failure have preserved ejection fraction characterized by diastolic dysfunction. The prevalance of diastolic dysfunction is higher in females and ...associates with multiple comorbidities such as hypertension (HT), obesity, hypercholesterolemia (HC), and diabetes mellitus (DM). Although its pathophysiology remains incompletely understood, it has been proposed that these comorbidities induce systemic inflammation, coronary microvascular dysfunction, and oxidative stress, leading to myocardial fibrosis, myocyte stiffening and, ultimately, diastolic dysfunction. Here, we tested this hypothesis in a swine model chronically exposed to three common comorbidities.
Methods and results
DM (induced by streptozotocin), HC (produced by high fat diet), and HT (resulting from renal artery embolization), were produced in 10 female swine, which were followed for 6 months. Eight female healthy swine on normal pig-chow served as controls. The DM + HC + HT group showed hyperglycemia, HC, hypertriglyceridemia, renal dysfunction and HT, which were associated with systemic inflammation. Myocardial superoxide production was markedly increased, due to increased NOX activity and eNOS uncoupling, and associated with reduced NO production, and impaired coronary small artery endothelium-dependent vasodilation. These abnormalities were accompanied by increased myocardial collagen content, reduced capillary/fiber ratio, and elevated passive cardiomyocyte stiffness, resulting in an increased left ventricular end-diastolic stiffness (measured by pressure–volume catheter) and a trend towards a reduced E/A ratio (measured by cardiac MRI), while ejection fraction was maintained.
Conclusions
The combination of three common comorbidities leads to systemic inflammation, myocardial oxidative stress, and coronary microvascular dysfunction, which associate with myocardial stiffening and LV diastolic dysfunction with preserved ejection fraction.
Background
Evaluation of cardiovascular prognosis in patients with stable coronary heart disease is based on clinical characteristics and biomarkers indicating dysglycemia, dyslipidemia, renal ...dysfunction, and possibly cardiac dysfunction. Inflammation plays a key role in atherosclerosis, but the association between inflammatory biomarkers and clinical outcomes is less studied in this population.
Methods and Results
Overall, 15 828 patients with coronary heart disease in the STABILITY (Stabilization of Atherosclerotic Plaque by Initiation of Darapladib Therapy) trial were randomized to treatment with darapladib or placebo and observed for a median of 3.7 years. In 14 611 patients, levels of interleukin‐6 (IL‐6) and high‐sensitivity C‐reactive protein were measured in plasma samples: median levels were 2.1 (interquartile range, 1.4–3.2) ng/L and 1.3 (interquartile range, 0.6–3.1) mg/L, respectively. Associations between continuous levels or quartile groups and adjudicated outcomes were evaluated by spline graphs and Cox regression adjusted for clinical factors and cardiovascular biomarkers. IL‐6 was associated with increased risk of major adverse cardiovascular events (quartile 4 versus quartile 1 hazard ratio HR, 1.60; 95% confidence interval CI, 1.30–1.97; P<0.0001); cardiovascular death (HR, 2.15; 95% CI, 1.53–3.04; P<0.0001); myocardial infarction (HR, 1.53; 95% CI, 1.14–2.04; P<0.05); all‐cause mortality (HR, 2.11; 95% CI, 1.62–2.76; P<0.0001); and risk of hospitalization for heart failure (HR, 2.28; 95% CI, 1.34–3.89; P<0.001). Cancer death was doubled in the highest IL‐6 quartile group (HR, 2.34; 95% CI, 1.20–4.53; P<0.05). High‐sensitivity C‐reactive protein was associated with both cardiovascular and non‐cardiovascular events in the unadjusted model, but these did not remain after multivariable adjustments.
Conclusions
IL‐6, an upstream inflammatory marker, was independently associated with the risk of major adverse cardiovascular events, cardiovascular and all‐cause mortality, myocardial infarction, heart failure, and cancer mortality in patients with stable coronary heart disease. IL‐6 might reflect a pathophysiological process involved in the development of these events.
Clinical Trial Registration
URL: http://www.clinicaltrials.gov. Unique identifier: NCT00799903.
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