Highlights • Arrhythmic, scale-free brain activity is distinct from brain oscillations. • Scale-free brain activity contains rich temporal structures beyond power spectrum. • Scale-free brain ...activity is relevant to task performance and arousal state. • Scale-free brain activity is altered in developmental and disease processes. • Computational modeling has shed light on the potential generative mechanisms of scale-free brain activity.
About 3196 EA-type binaries (EAs) were observed by LAMOST by 2017 June 16 and their spectral types were derived. Meanwhile, the stellar atmospheric parameters of 2020 EAs were determined. In this ...paper, those EAs are cataloged and their physical properties and evolutionary states are investigated. The period distribution of EAs suggests that the period limit of tidal locking for the close binaries is about 6 days. It is found that the metallicity of EAs is higher than that of EW-type binaries (EWs), indicating that EAs are generally younger than EWs and they are the progenitors of EWs. The metallicities of long-period EWs ( days) are the same as those of EAs with the same periods, while their values of Log (g) are usually smaller than those of EAs. These support the evolutionary process that EAs evolve into long-period EWs through the combination of angular momentum loss (AML) via magnetic braking and case A mass transfer. For short-period EWs, their metallicities are lower than those of EAs, while their gravitational accelerations are higher. These reveal that they may be formed from cool short-period EAs through AML via magnetic braking with little mass transfer. For some EWs with high metallicities, they may be contaminated by material from the evolution of unseen neutron stars and black holes or they have third bodies that may help them to form rapidly through a short timescale of pre-contact evolution. The present investigation suggests that the modern EW populations may have formed through a combination of these mechanisms.
The methylation index of branched tetraethers (MBT) and cyclization ratio of branched tetraethers (CBT) based on the distribution of branched glycerol dialkyl glycerol tetraethers (brGDGT) are useful ...proxies for the reconstruction of mean annual air temperature (MAT) and soil pH. Recently, a series of 6-methyl brGDGTs were identified which were previously co-eluted with 5-methyl brGDGTs. However, little is known about 6-methyl brGDGTs in the Qinghai–Tibetan Plateau (QTP), a critical region of the global climate system. Here, we analyze 30 surface soils covering a large area of the QTP, among which 6-methyl brGDGTs were the most abundant components (average 53 ± 17% of total brGDGT). The fractional abundance of 6-methyl brGDGTs showed a good correlation with soil pH, while the global MBT'5ME calibration overestimates MAT in the QTP. We therefore proposed a MBT5/6 index including both 5- and 6-methyl brGDGTs, presenting a strong correlation with MAT in QTP: MAT = −20.14 + 39.51 × MBT5/6 (n = 27, r2 = 0.82; RMSE = 1.3 °C). Another index, namely IBT (isomerization of branched tetraether), based on carbon skeleton isomerization of the 5-methyl to 6-methyl brGDGTs, is dependent on soil pH: pH = 6.77 − 1.56 × IBT (n = 27; r2 = 0.74, RMSE = 0.32). Our study suggests that changing the position of methyl group of brGDGTs may be another mechanism for some soil bacteria to adapt to the ambient pH change in addition to the well-known cyclization.
It has been shown recently that a significant portion of brain electrical field potentials consists of scale-free dynamics. These scale-free brain dynamics contain complex spatiotemporal structures ...and are modulated by task performance. Here we show that the fMRI signal recorded from the human brain is also scale free; its power-law exponent differentiates between brain networks and correlates with fMRI signal variance and brain glucose metabolism. Importantly, in parallel to brain electrical field potentials, the variance and power-law exponent of the fMRI signal decrease during task activation, suggesting that the signal contains more long-range memory during rest and conversely is more efficient at online information processing during task. Remarkably, similar changes also occurred in task-deactivated brain regions, revealing the presence of an optimal dynamic range in the fMRI signal. The scale-free properties of the fMRI signal and brain electrical field potentials bespeak their respective stationarity and nonstationarity. This suggests that neurovascular coupling mechanism is likely to contain a transformation from nonstationarity to stationarity. In summary, our results demonstrate the functional relevance of scale-free properties of the fMRI signal and impose constraints on future models of neurovascular coupling.
A widely held assumption is that spontaneous and task-evoked brain activity sum linearly, such that the recorded brain response in each single trial is the algebraic sum of the constantly changing ...ongoing activity and the stereotypical evoked activity. Using functional magnetic resonance imaging signals acquired from normal humans, we show that this assumption is invalid. Across widespread cortices, evoked activity interacts negatively with ongoing activity, such that higher prestimulus baseline results in less activation or more deactivation. As a consequence of this negative interaction, trial-to-trial variability of cortical activity decreases following stimulus onset. We further show that variability reduction follows overlapping but distinct spatial pattern from that of task-activation/deactivation and it contains behaviorally relevant information. These results favor an alternative perspective to the traditional dichotomous framework of ongoing and evoked activity. That is, to view the brain as a nonlinear dynamical system whose trajectory is tighter when performing a task. Further, incoming sensory stimuli modulate the brain's activity in a manner that depends on its initial state. We propose that across-trial variability may provide a new approach to brain mapping in the context of cognitive experiments.
Background
Exposure to environmental pollutants promotes Th2 cell responses. Aryl hydrocarbon receptor (AhR) activation aggravates allergic responses. Epithelium‐derived thymic stromal lymphopoietin ...(TSLP), interleukin (IL)‐25, and IL‐33 are implicated in the dysregulation of Th2 immune responses in severe allergic asthma.
Methods
Bronchial biopsies of 28 allergic severe asthma and 6 mild asthma subjects from highly polluted areas were analyzed for AhR nuclear translocation (NT), cytokine expression, and gene activation. Cultured primary epithelial cells were stimulated with diesel exhausted particles (DEP) to determine AhR‐mediated IL‐33, Il‐25, and TSLP synthesis and release.
Results
Primary bronchial epithelial cells exposed to DEP showed upregulation of IL‐33, IL‐25, and TSLP. These effects were abolished by knockdown of AhR by siRNA. Increased AhR/ARNT binding to promoters of IL‐33, IL‐25, and TSLP was found using chromatin immunoprecipitation (ChIP) assay. Allergic severe asthma with high AhR NT had higher bronchial gene and protein expression of IL‐33, IL‐25, and TSLP. These patients derived clinical benefit from anti‐IgE treatment.
Conclusion
Aryl hydrocarbon receptor activation by DEP mediates upregulation of IL‐33, IL‐25, and TSLP with Th2 activation, potentially linking environmental pollution and allergic severe asthma.
Environmental diesel exhaust particles (DEP) exposed to airway epithelium ligate cytoplasmic aryl hydrocarbon receptor (AhR), translocate to the nucleus with aryl hydrocarbon receptor nuclear translocator (ARNT), and then transactivate IL‐33, Il‐25, and TSLP gene expression. Patients with high AhR nucleus translocation overexpressed IL‐33, Il‐25, and TSLP cytokines compared to those with low. Patients with high AhR nucleus translocation are more response to anti‐IgE therapy compared to those with low.
Objective To determine the effects of longer term modest salt reduction on blood pressure, hormones, and lipids.Design Systematic review and meta-analysis.Data sources Medline, Embase, Cochrane ...Hypertension Group Specialised Register, Cochrane Central Register of Controlled Trials, and reference list of relevant articles.Inclusion criteria Randomised trials with a modest reduction in salt intake and duration of at least four weeks.Data extraction and analysis Data were extracted independently by two reviewers. Random effects meta-analyses, subgroup analyses, and meta-regression were performed.Results Thirty four trials (3230 participants) were included. Meta-analysis showed that the mean change in urinary sodium (reduced salt v usual salt) was −75 mmol/24 h (equivalent to a reduction of 4.4 g/day salt), and with this reduction in salt intake, the mean change in blood pressure was −4.18 mm Hg (95% confidence interval −5.18 to −3.18, I2=75%) for systolic blood pressure and −2.06 mm Hg (−2.67 to −1.45, I2=68%) for diastolic blood pressure. Meta-regression showed that age, ethnic group, blood pressure status (hypertensive or normotensive), and the change in 24 hour urinary sodium were all significantly associated with the fall in systolic blood pressure, explaining 68% of the variance between studies. A 100 mmol reduction in 24 hour urinary sodium (6 g/day salt) was associated with a fall in systolic blood pressure of 5.8 mm Hg (2.5 to 9.2, P=0.001) after adjustment for age, ethnic group, and blood pressure status. For diastolic blood pressure, age, ethnic group, blood pressure status, and the change in 24 hour urinary sodium explained 41% of the variance between studies. Meta-analysis by subgroup showed that in people with hypertension the mean effect was −5.39 mm Hg (−6.62 to −4.15, I2=61%) for systolic blood pressure and −2.82 mm Hg (−3.54 to −2.11, I2=52%) for diastolic blood pressure. In normotensive people, the figures were −2.42 mm Hg (−3.56 to −1.29, I2=66%) and −1.00 mm Hg (−1.85 to −0.15, I2=66%), respectively. Further subgroup analysis showed that the decrease in systolic blood pressure was significant in both white and black people and in men and women. Meta-analysis of data on hormones and lipids showed that the mean change was 0.26 ng/mL/h (0.17 to 0.36, I2=70%) for plasma renin activity, 73.20 pmol/L (44.92 to 101.48, I2=62%) for aldosterone, 187 pmol/L (39 to 336, I2=5%) for noradrenaline (norepinephrine), 37 pmol/L (−1 to 74, I2=12%) for adrenaline (epinephrine), 0.05 mmol/L (−0.02 to 0.11, I2=0%) for total cholesterol, 0.05 mmol/L (−0.01 to 0.12, I2=0%) for low density lipoprotein cholesterol, −0.02 mmol/L (−0.06 to 0.01, I2=16%) for high density lipoprotein cholesterol, and 0.04 mmol/L (−0.02 to 0.09, I2=0%) for triglycerides. Conclusions A modest reduction in salt intake for four or more weeks causes significant and, from a population viewpoint, important falls in blood pressure in both hypertensive and normotensive individuals, irrespective of sex and ethnic group. Salt reduction is associated with a small physiological increase in plasma renin activity, aldosterone, and noradrenaline and no significant change in lipid concentrations. These results support a reduction in population salt intake, which will lower population blood pressure and thereby reduce cardiovascular disease. The observed significant association between the reduction in 24 hour urinary sodium and the fall in systolic blood pressure, indicates that larger reductions in salt intake will lead to larger falls in systolic blood pressure. The current recommendations to reduce salt intake from 9-12 to 5-6 g/day will have a major effect on blood pressure, but a further reduction to 3 g/day will have a greater effect and should become the long term target for population salt intake.
The accumulation of myeloid-derived suppressor cells (MDSCs) has been observed in solid tumors and is correlated with tumor progression; however, the underlying mechanism is still poorly understood. ...In this study, we identified a mechanism by which tumor cells induce MDSC accumulation and expansion in the bladder cancer (BC) microenvironment via CXCL2/MIF-CXCR2 signaling. Elevated expression of CXCL2 and MIF and an increased number of CD33
MDSCs were detected in BC tissues, and these increases were significantly associated with advanced disease stage and poor patient prognosis (P<0.01). A positive association was observed between CXCL2 or MIF expression and the number of tumor-infiltrating CD33
MDSCs (P<0.01). Subsequently, we demonstrated that CD45
CD33
CD11b
HLA-DR
MDSCs from fresh BC tissues displayed high levels of suppressive molecules, including Arg1, iNOS, ROS, PDL-1 and P-STAT3, and stronger suppression of T-cell proliferation. Interestingly, these CD45
CD33
CD11b
HLA-DR
MDSCs exhibited increased CXCR2 expression compared with that in peripheral blood from BC patients or healthy controls (P<0.05). Chemotaxis assay revealed that bladder cancer cell line J82 induced MDSC migration via CXCL2/MIF-CXCR2 signaling in vitro. Mechanistic studies demonstrated that J82-induced MDSC trafficking and CXCR2 expression were associated with increased phosphorylation of p38, ERK and p65. Conversely, inhibition of the phosphorylation of p38, ERK or p65 decreased J82-induced MDSC trafficking and CXCR2 expression. CXCL2/MIF-stimulated activation of the mitogen-activated protein kinase and nuclear factor kappa B pathways in MDSCs was MyD88 dependent. Overall, our results identify the CXCL2/MIF-CXCR2 axis as an important mediator in MDSC recruitment and as predictors and potential therapeutic targets in BC patients.
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