Dust aerosol plays an important role in the Earth System. As a natural aerosol, dust aerosol is often calculated interactively in global climate models and temporal variations of dust emission in the ...past century are far less constrained compared to those of anthropogenic aerosol emissions. Here we evaluate dust emission in East Asia simulated by 15 climate models participating in the Coupled Model Intercomparison Project Phase 5. The results show that none of the models can reproduce the observed decline of dust event frequency during 1961–2005 over East Asia. The models tend to simulate either much less decline or even increase of dust emission. The discrepancy is mainly ascribed to weaker or opposite trends of surface wind speeds and precipitation in the models. These results cast a doubt on the interpretation of long‐term variations of dust‐affected fields in climate models and highlight the need for further improvements of the models.
Plain Language Summary
Atmospheric aerosol is one of key factors that influence climate change. Aerosols include anthropogenic aerosols (such as sulfate aerosol and black carbon from fossil fuel burning) and natural aerosols (such as dust that is emitted by strong winds over bare soil). Climate models are important tools we use to predict the climate in the future, and the reliability of climate models lies in their ability to reproduce the change of climate system in the past. Here we examine the ability of climate models in reproducing the long‐term change of dust storm frequency in East Asia. First, historical records of dust events show the dust activities decreased greatly during 1961 to 2005 over East Asia. Compared to this observation, current climate models are unable to reproduce the large decline of dust activities during 1961 to 2005. The reason is that climate models cannot capture the decrease of surface wind speed and increase of precipitation. These results imply that climate models may not represent well the change of meteorological elements (e.g., temperature and clouds) that will be affected by dust. Our results highlight urgent need to improve the performance of climate models in simulating long‐term dust change.
Key Points
CMIP5 models show similar dust source regions in East Asia but differ substantially in the boundaries of these regions
CMIP5 models cannot reproduce the observed large decline of dust events in East Asia during 1961‐2005
CMIP5 models simulate either smaller or opposite trends of surface wind speeds and precipitation, which lead to the discrepancy in dust
After long-term clinical application, traditional Chinese medicine (TCM) has accumulated rich experience in the stroke treatment. Huang-Qi-Long-Dan Granule (HQLDG) is a TCM formula that has been used ...in clinical for the treatment of acute ischemic stroke. However, its mechanism against ischemic stroke is still unknown. This study aimed to identify HQLDG’s effect against ischemic stroke and explore its underlying mechanism. 16s rRNA sequencing, metabolomics/tryptophan (Trp)-targeted metabolomics analysis and transcriptomic analysis were used to investigate HQLDG underlying therapeutic mechanism. Our results revealed that HQLDG significantly decreased the infarct volume, improved mouse behavior and brain slices pathological staining. In addition, it could ameliorate intestinal barrier damage and regulate tight junction gene expression. 16s rRNA, metabolomics and transcriptomics analysis revealed that HQLDG treatment significantly improved the composition of gut microbiota and Trp metabolism pathway, and further downregulated Th17/IL-17 signaling pathway. HQLDG treatment could significantly decrease serum inflammatory cytokines, IL-17A and IL-22; down-regulate Trp metabolism receptor gene (Ahr), inflammatory cytokines genes (IL-17a, IL-22), and an important coding gene for maintaining the mature Th17 (rorc) in both brain and intestinal tissues. In the contrary, after gut microbiota removal, this effect of HQLDG was impaired. HQLDG treated mouse fecal microbiota transplantation also had positive effect against tMCAO injury. Moreover, AhR inhibitor could decrease IL-17A immunofluorescence. These results suggested that the gut microbiota regulation might be an important intermediate in HQLDG against tMCAO injury. HQLDG might exert anti-ischemic stroke effects through the gut microbiota-Trp metabolism-Th17/IL-17 signaling, which provides new insights into HQLDG-mediated prevention in ischemic stroke.
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Dust particles, serving as ice-nucleating particles (INPs), may
impact the Arctic surface energy budget and regional climate by modulating
the mixed-phase cloud properties and lifetime. In addition ...to long-range
transport from low-latitude deserts, dust particles in the Arctic can
originate from local sources. However, the importance of high-latitude dust
(HLD) as a source of Arctic INPs (compared to low-latitude dust, LLD) and
its effects on Arctic mixed-phase clouds are overlooked. In this study, we
evaluate the contribution to Arctic dust loading and INP population from HLD and six LLD source regions by implementing a source-tagging technique for dust aerosols in version 1 of the US Department of Energy's Energy Exascale Earth System Model (E3SMv1). Our results show that HLD is responsible for 30.7 % of the total dust burden in the Arctic, whereas LLD from Asia and North Africa contributes 44.2 % and 24.2 %, respectively. Due to its limited vertical transport as a result of stable boundary layers, HLD contributes more in the lower troposphere, especially in boreal summer and autumn when the HLD emissions are stronger. LLD from North Africa and East Asia dominates the dust loading in the upper troposphere with peak contributions in boreal spring and winter. The modeled INP concentrations show better agreement with both ground and aircraft INP measurements in the Arctic when including HLD INPs. The HLD INPs are found to induce a net cooling effect (−0.24 W m−2 above 60∘ N) on the Arctic surface downwelling radiative flux by changing the cloud phase of the Arctic mixed-phase clouds. The magnitude of this cooling is larger than that induced by North African and East Asian dust (0.08 and −0.06 W m−2, respectively), mainly due to different seasonalities of HLD and LLD. Uncertainties of this study are discussed, which highlights the importance of further constraining the HLD emissions.
Here we report corin, a synthetic hybrid agent derived from the class I HDAC inhibitor (entinostat) and an LSD1 inhibitor (tranylcypromine analog). Enzymologic analysis reveals that corin potently ...targets the CoREST complex and shows more sustained inhibition of CoREST complex HDAC activity compared with entinostat. Cell-based experiments demonstrate that corin exhibits a superior anti-proliferative profile against several melanoma lines and cutaneous squamous cell carcinoma lines compared to its parent monofunctional inhibitors but is less toxic to melanocytes and keratinocytes. CoREST knockdown, gene expression, and ChIP studies suggest that corin's favorable pharmacologic effects may rely on an intact CoREST complex. Corin was also effective in slowing tumor growth in a melanoma mouse xenograft model. These studies highlight the promise of a new class of two-pronged hybrid agents that may show preferential targeting of particular epigenetic regulatory complexes and offer unique therapeutic opportunities.
The effective segmentation of clouds and cloud shadows is crucial for surface feature extraction, climate monitoring, and atmospheric correction, but it remains a critical challenge in remote sensing ...image processing. Cloud features are intricate, with varied distributions and unclear boundaries, making accurate extraction difficult, with only a few networks addressing this challenge. To tackle these issues, we introduce a multi-scale receptive field aggregation network (MRFA-Net). The MRFA-Net comprises an MRFA-Encoder and MRFA-Decoder. Within the encoder, the net includes the asymmetric feature extractor module (AFEM) and multi-scale attention, which capture diverse local features and enhance contextual semantic understanding, respectively. The MRFA-Decoder includes the multi-path decoder module (MDM) for blending features and the global feature refinement module (GFRM) for optimizing information via learnable matrix decomposition. Experimental results demonstrate that our model excelled in generalization and segmentation performance when addressing various complex backgrounds and different category detections, exhibiting advantages in terms of parameter efficiency and computational complexity, with the MRFA-Net achieving a mean intersection over union (MIoU) of 94.12% on our custom Cloud and Shadow dataset, and 87.54% on the open-source HRC_WHU dataset, outperforming other models by at least 0.53% and 0.62%. The proposed model demonstrates applicability in practical scenarios where features are difficult to distinguish.
Record rainfall and severe flooding struck eastern China in the summer of 2020. The extreme summer rainfall occurred during the COVID-19 pandemic, which started in China in early 2020 and spread ...rapidly across the globe. By disrupting human activities, substantial reductions in anthropogenic emissions of greenhouse gases and aerosols might have affected regional precipitation in many ways. Here, we investigate such connections and show that the abrupt emissions reductions during the pandemic strengthened the summer atmospheric convection over eastern China, resulting in a positive sea level pressure anomaly over northwestern Pacific Ocean. The latter enhanced moisture convergence to eastern China and further intensified rainfall in that region. Modeling experiments show that the reduction in aerosols had a stronger impact on precipitation than the decrease of greenhouse gases did. We conclude that through abrupt emissions reductions, the COVID-19 pandemic contributed importantly to the 2020 extreme summer rainfall in eastern China.
SWI/SNF remodelers play a key role in regulating chromatin architecture and gene expression. Here, we report the cryo-EM structure of the Saccharomyces cerevisiae Swi/Snf complex in a nucleosome-free ...state. The structure consists of a stable triangular base module and a flexible Arp module. The conserved subunits Swi1 and Swi3 form the backbone of the complex and closely interact with other components. Snf6, which is specific for yeast Swi/Snf complex, stabilizes the binding of the ATPase-containing subunit Snf2 to the base module. Comparison of the yeast Swi/Snf and RSC complexes reveals conserved structural features that govern the assembly and function of these two subfamilies of chromatin remodelers. Our findings complement those from recent structures of the yeast and human chromatin remodelers and provide further insights into the assembly and function of the SWI/SNF remodelers.
Black carbon (BC) and dust impart significant effects on the South Asian
monsoon (SAM), which is responsible for ∼80 % of the
region's annual precipitation. This study implements a ...variable-resolution
(VR) version of the Community Earth System Model (CESM) to quantify two
radiative effects of absorbing BC and dust on the SAM. Specifically, this
study focuses on the snow darkening effect (SDE), as well as how these
aerosols interact with incoming and outgoing radiation to facilitate an
atmospheric response (i.e., aerosol–radiation interactions, ARIs). By running
sensitivity experiments, the individual effects of SDE and ARI are
quantified, and a theoretical framework is applied to assess these aerosols'
impacts on the SAM. It is found that ARIs of absorbing aerosols warm the
atmospheric column in a belt coincident with the May–June averaged location
of the subtropical jet, bringing forth anomalous upper-tropospheric
(lower-tropospheric) anticyclogenesis (cyclogenesis) and divergence
(convergence). This anomalous arrangement in the mass fields brings forth
enhanced rising vertical motion across South Asia and a stronger westerly
low-level jet, the latter of which furnishes the Indian subcontinent with
enhanced Arabian Gulf moisture. Precipitation increases of 2 mm d−1 or
more (a 60 % increase in June) result across much of northern India from
May through August, with larger anomalies (+5 to +10 mm d−1) in the
western Indian mountains and southern Tibetan Plateau (TP) mountain ranges due to orographic
and anabatic enhancement. Across the Tibetan Plateau foothills, SDE by BC
aerosols drives large precipitation anomalies of > 6 mm d−1
(a 21 %–26 % increase in May and June), comparable to ARI of absorbing
aerosols from April through August. Runoff changes accompany BC SDE-induced
snow changes across Tibet, while runoff changes across India result
predominantly from dust ARI. Finally, there are large differences in the
simulated SDE between the VR and traditional 1∘ simulations, the latter
of which simulates a much stronger SDE and more effectively modifies the
regional circulation.
As an important component of the Central Asian Orogenic Belt (CAOB), the West Junggar represents a natural laboratory to explore intracontinental deformation in a complex terrane. Although some ...low-temperature thermochronological studies have been conducted in this range, the number of exhumation stages and the corresponding driving forces behind exhumation remain highly debated. In particular, the exhumation history of the northern West Junggar remains poorly studied owing to a lack of data. Here, we present a study that integrates apatite fission track (AFT) and (UTh)/ He (AHe) dating from the igneous rock in the Sawur Mountains in northern West Junggar to further constrain the exhumation history of the region. AFT dating of the samples dominantly yields Late Triassic ages (200–227 Ma) with mean track lengths (MTLs) varying between 13.33 and 14.98 μm, while AHe dating produced widely dispersed Late Triassic to Late Cretaceous single grain ages (73–215 Ma), with sample mean ages between 100 and 195 Ma. Inverse thermal history modeling of our results and analysis of age-elevation relationships reveal that the Sawur Mountains experienced an extended period of rapid cooling related to local exhumation during the Middle–Late Triassic. A gradual reduction in surface relief following rapid erosion is related to peneplanation processes. The timing and patterns of this exhumation indicate it was caused by reverse oblique-lip reactivation of older strike-slip faults, and it can be explained as the response to the far-field effects of the final closure of the Paleo-Asian Ocean.
•Middle to Late Triassic rapid cooling is preserved throughout the West Junggar.•The reactivation of strike-slip faults with limited vertical motion controlled the rapid exhumation in the Triassic.•The deformation's most likely trigger is the Paleo-Asian Ocean's final closure.
The genus Rosa (Rosaceae) contains approximately 200 species, most of which have high ecological and economic values. Chloroplast genome sequences are important for studying species differentiation, ...phylogeny, and RNA editing.
In this study, the chloroplast genomes of three Rosa species, Rosa hybrida, Rosa acicularis, and Rosa rubiginosa, were assembled and compared with other reported Rosa chloroplast genomes. To investigate the RNA editing sites in R. hybrida (commercial rose cultivar), we mapped RNA-sequencing data to the chloroplast genome and analyzed their post-transcriptional features. Rosa chloroplast genomes presented a quadripartite structure and had highly conserved gene order and gene content. We identified four mutation hotspots (ycf3-trnS, trnT-trnL, psbE-petL, and ycf1) as candidate molecular markers for differentiation in the Rosa species. Additionally, 22 chloroplast genomic fragments with a total length of 6,192 bp and > 90% sequence similarity with their counterparts were identified in the mitochondrial genome, representing 3.96% of the chloroplast genome. Phylogenetic analysis including all sections and all subgenera revealed that the earliest divergence in the chloroplast phylogeny roughly distinguished species of sections Pimpinellifoliae and Rosa and subgenera Hulthemia. Moreover, DNA- and RNA-sequencing data revealed 19 RNA editing sites, including three synonymous and 16 nonsynonymous, in the chloroplast genome of R. hybrida that were distributed among 13 genes.
The genome structure and gene content of Rosa chloroplast genomes are similar across various species. Phylogenetic analysis based on the Rosa chloroplast genomes has high resolution. Additionally, a total of 19 RNA editing sites were validated by RNA-Seq mapping in R. hybrida. The results provide valuable information for RNA editing and evolutionary studies of Rosa and a basis for further studies on genomic breeding of Rosa species.
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