141 research outputs found
Automated Dilated Spatio-Temporal Synchronous Graph Modeling for Traffic Prediction
Accurate traffic prediction is a challenging task in intelligent
transportation systems because of the complex spatio-temporal dependencies in
transportation networks. Many existing works utilize sophisticated temporal
modeling approaches to incorporate with graph convolution networks (GCNs) for
capturing short-term and long-term spatio-temporal dependencies. However, these
separated modules with complicated designs could restrict effectiveness and
efficiency of spatio-temporal representation learning. Furthermore, most
previous works adopt the fixed graph construction methods to characterize the
global spatio-temporal relations, which limits the learning capability of the
model for different time periods and even different data scenarios. To overcome
these limitations, we propose an automated dilated spatio-temporal synchronous
graph network, named Auto-DSTSGN for traffic prediction. Specifically, we
design an automated dilated spatio-temporal synchronous graph (Auto-DSTSG)
module to capture the short-term and long-term spatio-temporal correlations by
stacking deeper layers with dilation factors in an increasing order. Further,
we propose a graph structure search approach to automatically construct the
spatio-temporal synchronous graph that can adapt to different data scenarios.
Extensive experiments on four real-world datasets demonstrate that our model
can achieve about 10% improvements compared with the state-of-art methods.
Source codes are available at https://github.com/jinguangyin/Auto-DSTSGN
Onset of nonlinear electroosmotic flow under AC electric field
Nonlinearity of electroosmotic flows (EOFs) is ubiquitous and plays a crucial
role in the mass and energy transfer in ion transport, specimen mixing,
electrochemistry reaction, and electric energy storage and utilizing. When and
how the transition from a linear regime to a nonlinear one is essential for
understanding, prohibiting or utilizing nonlinear EOF. However, suffers the
lacking of reliable experimental instruments with high spatial and temporal
resolutions, the investigation of the onset of nonlinear EOF still stays in
theory. Herein, we experimentally studied the velocity fluctuations of EOFs
driven by AC electric field via ultra-sensitive fluorescent blinking tricks.
The linear and nonlinear AC EOFs are successfully identified from both the time
trace and energy spectra of velocity fluctuations. The critical electric field
() separating the two statuses is determined and is discovered by
defining a generalized scaling law with respect to the convection velocity
() and AC frequency () as ~. The
universal control parameters are determined with surprising accuracy for
governing the status of AC EOFs. We hope the current investigation could be
essential in the development of both theory and applications of nonlinear EOF
Electrokinetic origin of swirling flow on nanoscale interface
The zeta () potential is a pivotal metric for characterizing the
electric field topology within an electric double layer - an important
phenomenon on phase interface. It underpins critical processes in diverse
realms such as chemistry, biomedical engineering, and micro/nanofluidics. Yet,
local measurement of potential at the interface has historically
presented challenges, leading researchers to simplify a chemically homogenized
surface with a uniform potential. In the current investigation, we
present evidence that, within a microchannel, the spatial distribution of
potential across a chemically homogeneous solid-liquid interface can
become two-dimensional (2D) under an imposed flow regime, as disclosed by a
state-of-art fluorescence photobleaching electrochemistry analyzer (FLEA)
technique. The potential' s propensity to become increasingly negative
downstream, presents an approximately symmetric, V-shaped pattern in the
spanwise orientation. Intriguingly, and of notable significance to chemistry
and engineering, this 2D potential framework was found to
electrokinetically induce swirling flows in tens of nanometers, aligning with
the streamwise axis, bearing a remarkable resemblance to the well-documented
hairpin vortices in turbulent boundary layers. Our findings gesture towards a
novel perspective on the genesis of vortex structures in nanoscale.
Additionally, the FLEA technique emerges as a potent tool for discerning
potential at a local scale with high resolution, potentially
accelerating the evolution and applications of novel surface material
Exploring Progress in Multivariate Time Series Forecasting: Comprehensive Benchmarking and Heterogeneity Analysis
Multivariate Time Series (MTS) widely exists in real-word complex systems,
such as traffic and energy systems, making their forecasting crucial for
understanding and influencing these systems. Recently, deep learning-based
approaches have gained much popularity for effectively modeling temporal and
spatial dependencies in MTS, specifically in Long-term Time Series Forecasting
(LTSF) and Spatial-Temporal Forecasting (STF). However, the fair benchmarking
issue and the choice of technical approaches have been hotly debated in related
work. Such controversies significantly hinder our understanding of progress in
this field. Thus, this paper aims to address these controversies to present
insights into advancements achieved. To resolve benchmarking issues, we
introduce BasicTS, a benchmark designed for fair comparisons in MTS
forecasting. BasicTS establishes a unified training pipeline and reasonable
evaluation settings, enabling an unbiased evaluation of over 30 popular MTS
forecasting models on more than 18 datasets. Furthermore, we highlight the
heterogeneity among MTS datasets and classify them based on temporal and
spatial characteristics. We further prove that neglecting heterogeneity is the
primary reason for generating controversies in technical approaches. Moreover,
based on the proposed BasicTS and rich heterogeneous MTS datasets, we conduct
an exhaustive and reproducible performance and efficiency comparison of popular
models, providing insights for researchers in selecting and designing MTS
forecasting models
Transcriptomic analysis reveals ethylene signal transduction genes involved in pistil development of pumpkin
Development of female flowers is an important process that directly affects the yield of Cucubits. Little information is available on the sex determination and development of female flowers in pumpkin, a typical monoecious plant. In the present study, we used aborted and normal pistils of pumpkin for RNA-Seq analysis and determined the differentially expressed genes (DEGs) to gain insights into the molecular mechanism underlying pistil development in pumpkin. A total of 3,817 DEGs were identified, among which 1,341 were upregulated and 2,476 were downregulated. The results of transcriptome analysis were confirmed by real-time quantitative RT-PCR. KEGG enrichment analysis showed that the DEGs were significantly enriched in plant hormone signal transduction and phenylpropanoid biosynthesis pathway. Eighty-four DEGs were enriched in the plant hormone signal transduction pathway, which accounted for 12.54% of the significant DEGs, and most of them were annotated as predicted ethylene responsive or insensitive transcription factor genes. Furthermore, the expression levels of four ethylene signal transduction genes in different flower structures (female calyx, pistil, male calyx, stamen, leaf, and ovary) were investigated. The ethyleneresponsive DNA binding factor, ERDBF3, and ethylene responsive transcription factor, ERTF10, showed the highest expression in pistils and the lowest expression in stamens, and their expression levels were 78- and 162-times more than that in stamens, respectively. These results suggest that plant hormone signal transduction genes, especially ethylene signal transduction genes, play an important role in the development of pistils in pumpkin. Our study provides a theoretical basis for further understanding of the mechanism of regulation of ethylene signal transduction genes in pistil development and sex determination in pumpkin
Experimental impacts of grazing on grassland biodiversity and function are explained by aridity
Grazing by domestic herbivores is the most widespread land use on the planet, and also a major global change driver in grasslands. Yet, experimental evidence on the long-term impacts of livestock grazing on biodiversity and function is largely lacking. Here, we report results from a network of 10 experimental sites from paired grazed and ungrazed grasslands across an aridity gradient, including some of the largest remaining native grasslands on the planet. We show that aridity partly explains the responses of biodiversity and multifunctionality to long-term livestock grazing. Grazing greatly reduced biodiversity and multifunctionality in steppes with higher aridity, while had no effects in steppes with relatively lower aridity. Moreover, we found that long-term grazing further changed the capacity of above- and below-ground biodiversity to explain multifunctionality. Thus, while plant diversity was positively correlated with multifunctionality across grasslands with excluded livestock, soil biodiversity was positively correlated with multifunctionality across grazed grasslands. Together, our cross-site experiment reveals that the impacts of long-term grazing on biodiversity and function depend on aridity levels, with the more arid sites experiencing more negative impacts on biodiversity and ecosystem multifunctionality. We also highlight the fundamental importance of conserving soil biodiversity for protecting multifunctionality in widespread grazed grasslands
A live-cell image-based machine learning strategy for reducing variability in PSC differentiation systems
The differentiation of pluripotent stem cells (PSCs) into diverse functional cell types provides a promising solution to support drug discovery, disease modeling, and regenerative medicine. However, functional cell differentiation is currently limited by the substantial line-to-line and batch-to-batch variabilities, which severely impede the progress of scientific research and the manufacturing of cell products. For instance, PSC-to-cardiomyocyte (CM) differentiation is vulnerable to inappropriate doses of CHIR99021 (CHIR) that are applied in the initial stage of mesoderm differentiation. Here, by harnessing live-cell bright-field imaging and machine learning (ML), we realize real-time cell recognition in the entire differentiation process, e.g., CMs, cardiac progenitor cells (CPCs), PSC clones, and even misdifferentiated cells. This enables non-invasive prediction of differentiation efficiency, purification of ML-recognized CMs and CPCs for reducing cell contamination, early assessment of the CHIR dose for correcting the misdifferentiation trajectory, and evaluation of initial PSC colonies for controlling the start point of differentiation, all of which provide a more invulnerable differentiation method with resistance to variability. Moreover, with the established ML models as a readout for the chemical screen, we identify a CDK8 inhibitor that can further improve the cell resistance to the overdose of CHIR. Together, this study indicates that artificial intelligence is able to guide and iteratively optimize PSC differentiation to achieve consistently high efficiency across cell lines and batches, providing a better understanding and rational modulation of the differentiation process for functional cell manufacturing in biomedical applications
Label-free visualization of carbapenemase activity in living bacteria
Evaluating enzyme activity intracellularly on natural substrates is a significant experimental challenge in biomedical research. We report a labelâfree method for realâtime monitoring of the catalytic behavior of classâ
A, B, and D carbapenemases in live bacteria based on measurement of heat changes. By this means, novel biphasic kinetics for classâ
D OXAâ48 with imipenem as substrate is revealed, providing a new approach to detect OXAâ48âlike producers. This inâcell calorimetry approach offers major advantages in the rapid screening (10â
min) of carbapenemaseâproducing Enterobacteriaceae from 142 clinical bacterial isolates, with superior sensitivity (97â%) and excellent specificity (100â%) compared to conventional methods. As a general, labelâfree method for the study of living cells, this protocol has potential for application to a wider range and variety of cellular components and physiological processes
Discovery of a novel, liver-targeted thyroid hormone receptor-β agonist, CS271011, in the treatment of lipid metabolism disorders
IntroductionThyroid hormone receptor β (THR-β) plays a critical role in metabolism regulation and has become an attractive target for treating lipid metabolism disorders in recent years. Thus, in this study, we discovered CS271011, a novel THR-β agonist, and assessed the safety and efficiency of CS271011 compared to MGL-3196 in vitro and in vivo. MethodsWe conducted luciferase reporter gene assays to assess the activation of THR-β and ι in vitro. C57BL/6J mice were fed a high-fat diet for 12 weeks, CS271011 was administered by gavage at the dose of 1 mg/kg and 3 mg/kg, and MGL-3196 was administered at the dose of 3 mg/kg for 10 weeks. Body weight, food intake, serum and hepatic parameters, histological analysis, pharmacokinetic studies, RNA sequencing of the liver and heart, and expression of hepatic lipid-metabolic genes were determined to evaluate the safety and efficiency of CS271011. ResultsCompared with MGL-3196, CS271011 showed higher THR-β activation in vitro. In the diet-induced obesity mice model, CS271011 demonstrated favourable pharmacokinetic properties in mice and was enriched in the liver. Finally, CS271011 improved dyslipidaemia and reduced liver steatosis in the diet-induced obesity murine model. Mechanistically, CS271011 and MGL-3196 showed potent regulation of lipid metabolism-related genes. ConclusionsCS271011 is a potent and liver-targeted THR-β agonist for treating lipid metabolism disorders
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