Enthalpies of nine TiO2 polymorphs under different pressures are presented to study the relative stability of the TiO2 polymorphs. It is important to include the dispersion correction for van der ...Waals interaction and the Hubbard U term for the Ti 3d orbital in the DFT-GGA calculation to correctly reproduce the relative stability of rutile, brookite, and anatase. Band structures for the TiO2 polymorphs are calculated by density functional theory with generalized gradient approximation, and the band energies at high symmetry k-points are corrected using the GW method to accurately determine the band gap. The differences between direct band gap energies and indirect band gap energies are very small for rutile and columbite-structured TiO2, indicating a quasi-direct band gap character. For optical response calculations, two-particle effects have been included by solving the Bethe–Salpeter equation for Coulomb correlated electron–hole pairs. TiO2 with baddeleyite, pyrite, and fluorite structures has optical transitions in the violet light region.
Psychiatric diseases have the lowest probability of success in clinical drug development. This presents not only an issue to address the unmet medical needs of patients, but also a hurdle for ...pharmaceutical and biotech industry to continue R&D in this disease area. Fundamental pharmacokinetic and pharmacodynamic principles provide an understanding of the drug exposure, target binding and pharmacological activity at the target site of action for a new drug candidate. Collectively, these principles determine the likelihood of testing the mechanism of action and enhancing the likelihood of candidate survival in Phase 2 clinical development, therefore, they are termed as the "three pillars of survival." Human Phase 1 pharmacokinetic and pharmacodynamic studies provide evidence of the three pillars. Electroencephalogram (EEG) assessments and cognitive function tests in schizophrenia patients can provide proof of pharmacology and ensure that a pharmacological active regimen will be tested in Phase 2 proof of concept (POC) studies for the treatment of cognitive impairment associated with schizophrenia (CIAS).
Two-dimensional (2D) atomically thin perovskites with strongly bound excitons are highly promising for optoelectronic applications. However, the nature of nonradiative processes that limit the ...photoluminescence (PL) efficiency remains elusive. Here, we present time-resolved and temperature-dependent PL studies to systematically address the intrinsic exciton relaxation pathways in layered (C4H9NH3)2(CH3NH3) n−1Pb n I3n+1 (n = 1, 2, 3) structures. Our results show that scatterings via deformation potential by acoustic and homopolar optical phonons are the main scattering mechanisms for excitons in ultrathin single exfoliated flakes, exhibiting a T γ (γ = 1.3 to 1.9) temperature dependence for scattering rates. We attribute the absence of polar optical phonon and defect scattering to efficient screening of Coulomb potential, similar to what has been observed in 3D perovskites. These results establish an understanding of the origins of nonradiative pathways and provide guidelines for optimizing PL efficiencies of atomically thin 2D perovskites.
COVID‐19 is characterized by dysregulated immune responses, metabolic dysfunction and adverse effects on the function of multiple organs. To understand host responses to COVID‐19 pathophysiology, we ...combined transcriptomics, proteomics, and metabolomics to identify molecular markers in peripheral blood and plasma samples of 66 COVID‐19‐infected patients experiencing a range of disease severities and 17 healthy controls. A large number of expressed genes, proteins, metabolites, and extracellular RNAs (exRNAs) exhibit strong associations with various clinical parameters. Multiple sets of tissue‐specific proteins and exRNAs varied significantly in both mild and severe patients suggesting a potential impact on tissue function. Chronic activation of neutrophils, IFN‐I signaling, and a high level of inflammatory cytokines were observed in patients with severe disease progression. In contrast, COVID‐19‐infected patients experiencing milder disease symptoms showed robust T‐cell responses. Finally, we identified genes, proteins, and exRNAs as potential biomarkers that might assist in predicting the prognosis of SARS‐CoV‐2 infection. These data refine our understanding of the pathophysiology and clinical progress of COVID‐19.
SYNOPSIS
Proteomics, metabolomics and RNAseq data map immune responses in COVID‐19 patients with different disease severity, revealing molecular makers associated with disease progression and alterations of tissue‐specific proteins.
A multi‐omics profiling of the host response to SARS‐CoV2 infection in 66 clinically diagnosed and laboratory confirmed COVID‐19 patients and 17 uninfected controls.
Significant correlations between multi‐omics data and key clinical parameters.
Alteration of tissue‐specific proteins and exRNAs.
Enhanced activation of immune responses is associated with COVID‐19 pathogenesis.
Biomarkers to predict COVID‐19 clinical outcomes pending clinical validation as prospective marker.
Proteomics, metabolomics and RNAseq data map immune responses in COVID‐19 patients with different disease severity, revealing molecular makers associated with disease progression and alterations of tissue‐specific proteins.
Ambient exposure to fine particulate matter (PM2.5) is known to harm public health in China. Satellite remote sensing measurements of aerosol optical depth (AOD) were statistically associated with ...in-situ observations after 2013 to predict PM2.5 concentrations nationwide, while the lack of surface monitoring data before 2013 have created difficulties in historical PM2.5 exposure estimates. Hindcast approaches using statistical models or chemical transport models (CTMs) were developed to overcome this limitation, while those approaches still suffer from incomplete daily coverage due to missing AOD data or limited accuracy due to uncertainties of CTMs. Here we developed a new machine learning (ML) model with high-dimensional expansion (HD-expansion) of numerous predictors (including AOD and other satellite covariates, meteorological variables and CTM simulations). Through comprehensive characterization of the nonlinear effects of, and interactions among different predictors, the HD-expansion parameterized the association between PM2.5 and AOD as a nonlinear function of space and time covariates (e.g., planetary boundary layer height and relative humidity). In this way, the PM2.5-AOD association can vary spatiotemporally. We trained the model with data from 2013 to 2016 and evaluated its performance using annually-iterated cross-validation, which iteratively held out the in-situ observations for a whole calendar year (as testing data) to examine the predictions from a model trained by the rest of the observations. Our estimates were found to be in good agreement with in-situ observations, with correlation coefficients (R2) of 0.61, 0.68, and 0.75 for daily, monthly and annual averages, respectively. To interpolate the missing predictions due to incomplete AOD data, we incorporated a generalized additive model into the ML model. The two-stage estimates of PM2.5 sacrificed the prediction accuracy on a daily timescale (R2 = 0.55), but achieved complete spatiotemporal coverage and improved the accuracy of monthly (R2 = 0.71) and annual (R2 = 0.77) averages. The model was then used to predict daily PM2.5 concentrations during 2000–2016 across China and estimate long-term trends in PM2.5 for the period. We found that population-weighted concentrations of PM2.5 significantly increased, by 2.10 (95% confidence interval (CI): 1.74, 2.46) μg/m3/year during 2000–2007, and rapidly decreased by 4.51 (3.12, 5.90) μg/m3/year during 2013–2016. In this study, we produced AOD-based estimates of historical PM2.5 with complete spatiotemporal coverage, which were evidenced as accurate, particularly in middle and long term. The products could support large-scale epidemiological studies and risk assessments of ambient PM2.5 in China and can be accessed via the website (http://www.meicmodel.org/dataset-phd.html).
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•Estimating historical PM2.5 in China is difficult due to lack of in-situ data.•Hindcast approaches suffers from incomplete daily coverage due to missing AOD.•We design a model with high-dimensional representation of many predictors of PM2.5.•We generate daily PM2.5 maps with a spatial resolution of 0.1° in China, 2000–2016.•The spatiotemporally continuous estimates are well correlated with in-situ PM2.5.
Mental disorders have been associated with various aspects of anthropogenic change to the environment, but the relative effects of different drivers are uncertain. Here we estimate associations ...between multiple environmental factors (air quality, residential greenness, mean temperature, and temperature variability) and self-assessed mental health scores for over 20,000 Chinese residents. Mental health scores were surveyed in 2010 and 2014, allowing us to link changes in mental health to the changes in environmental variables. Increases in air pollution and temperature variability are associated with higher probabilities of declined mental health. Mental health is statistically unrelated to mean temperature in this study, and the effect of greenness on mental health depends on model settings, suggesting a need for further study. Our findings suggest that the environmental policies to reduce emissions of air pollution or greenhouse gases can improve mental health of the public in China.
Large binding energy and unique exciton fine structure make the transition metal dichalcogenides (TMDCs) an ideal platform to study exciton behaviors in two-dimensional (2D) systems. While excitons ...in these systems have been extensively researched, there currently lacks a consensus on mechanisms that control dynamics. In this Perspective, we discuss extrinsic and intrinsic factors in exciton dynamics, transport, and annihilation in 2D TMDCs. Intrinsically, dark and bright exciton energy splitting is likely to play a key role in modulating the dynamics. Extrinsically, defect scattering is prevalent in single-layer TMDCs, which leads to rapid picosecond decay and limits exciton transport. The exciton–exciton annihilation process in single-layer TMDCs is highly efficient, playing an important role in the nonradiative recombination rate in the high exciton density regime. Future challenges and opportunities to control exciton dynamics are discussed.
Singlet fission is promising for redistributing the solar spectrum to overcome the Shockley–Queisser limit for single-junction solar cells using molecular materials. Despite recent experimental and ...theoretical advances in understanding the underlying mechanisms, how exciton transport is coupled to singlet fission dynamics is much less explored. In this Perspective, we examine exciton transport in singlet fission materials, highlighting the use of transient absorption microscopy (TAM) to track the population of different states in both spatial and temporal domains. In contrast to the conventional picture where singlet and triplet excitons migrate independently, TAM measurements of acene single crystals reveal cooperative transport between fast-moving singlet and slow-moving triplet excitons. Such cooperative transport is unique to singlet fission materials and allows hundreds of nanometers triplet migration on the nanosecond time scale, beneficial for solar cell applications. The transport of triplet pair intermediates and general criteria for achieving cooperative singlet–triplet transport are also discussed.
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