Abstract
Vegetation greening in China has been extensively examined, but little is known about its seasonal characteristics and its association with soil moisture (SM) and temperature changes. Using ...high-resolution (0.1°, 8 d) datasets of leaf area index (LAI), together with SM, soil temperature (ST) datasets, and the dominance analysis method, this study is designed to detect seasonal vegetation changes across China during 1981–2018 and its links to climate change. The results show that 56.8% of land area across China experienced a greening trend while 6.6% browning trend through 1981–2018. LAI increasing area expanded to a maximum of 59.3% in spring and the decreasing area reached a maximum of 10.6% in autumn. Spring increases in LAI in main vegetation regions were significantly correlated with positive ST anomalies, while autumn decreases in LAI except sparsely vegetated regions were correlated with negative SM anomalies. Combined SM and temperature anomalies explain 10.9% of the observed LAI changes, which is 4 times larger than that directly explained by precipitation and surface air temperature (2.7%). The warming of soil under climate change was driving the LAI increases, while drying was largely responsible for LAI decreases. These findings provide further evidence of climate change impacts on regional ecosystems and highlight the importance of soil heat and water conditions in translating global warming signals.
With rapid Internet development and multimedia technologies, video applications are gradually becoming essential to people's lives. However, the data security problems that follow are becoming ...increasingly prominent. For the problem of excessive video encoding time after encryption of a high-dimensional chaos encryption algorithm, this paper uses chaotic pseudo-random sequences generated by the integer dynamic cross-coupling tent mapping model as the keystream. It then selectively encrypts them with some key syntax elements in video encoding. Several experimental tests were conducted to analyze the proposed algorithm's effectiveness and security, including information entropy, key space analysis, edge detection analysis, and alternative attack analysis. The experimental results show that the entropy value of the test frames is greater than 7.99, and the key space of the proposed algorithm is 2
992
. In addition, the encryption algorithm has a low computational cost and the overall encoding time and encryption time consumption of the test video increase by 1.171% on average. The bit stream length increases to 0 after video encryption, which does not affect the video compression ratio. Moreover, the algorithm can resist edge detection attacks and substitution attacks. The algorithm has high timeliness and resistance to attack in terms of real-time and reliability of video encryption transmission.
Myocardial infarction afflicts close to three quarters of a million Americans annually, resulting in reduced heart function, arrhythmia, and frequently death. Cardiomy- ocyte death reduces the ...heart＇s pump capacity while the deposition of a non-conductive scar incurs the risk of arrhythmia. Direct cardiac reprogramming emerged as a novel technology to simultaneously reduce scar tissue and generate new cardiomyocytes to restore cardiac function. This technology converts endogenous cardiac fibroblasts directly into induced cardiomyocyte-like cells using a variety of cocktails including transcription factors, microRNAs, and small molecules. Although promising, direct cardiac reprogramming is still in its fledging phase, and numerous barriers have to be overcome prior to its clinical application. This review discusses current findings to optimize reprogramming efficiency, including reprogramming factor cocktails and stoichiometry, epigenetic barriers to cell fate reprogramming, incomplete conversion and residual fibroblast identity, requisite growth factors, and environmental cues. Finally, we address the current challenges and future directions for the field.
Abstract
Aims
The precise cellular identity and molecular features of non-myocytes (non-CMs) in a mammalian heart at a single-cell level remain elusive. Depiction of epigenetic landscape with ...transcriptomic signatures using the latest single-cell multi-omics has the potential to unravel the molecular programs underlying the cellular diversity of cardiac non-myocytes. Here, we characterized the molecular and cellular features of cardiac non-CM populations in the adult murine heart at the single-cell level.
Methods and results
Through single-cell dual omics analysis, we mapped the epigenetic landscapes, characterized the transcriptomic profiles and delineated the molecular signatures of cardiac non-CMs in the adult murine heart. Distinct cis-regulatory elements and trans-acting factors for the individual major non-CM cell types (endothelial cells, fibroblast, pericytes, and immune cells) were identified. In particular, unbiased sub-clustering and functional annotation of cardiac fibroblasts (FBs) revealed extensive FB heterogeneity and identified FB sub-types with functional states related to the cellular response to stimuli, cytoskeleton organization, and immune regulation, respectively. We further explored the function of marker genes Hsd11b1 and Gfpt2 that label major FB subpopulations and determined the distribution of Hsd11b1+ and Gfp2+ FBs in murine healthy and diseased hearts.
Conclusions
In summary, we characterized the non-CM cellular identity at the transcriptome and epigenome levels using single-cell omics approaches and discovered previously unrecognized cardiac fibroblast subpopulations with unique functional states.
Graphical Abstract
Cardiomyocytes derived from induced pluripotent stem cells (iPSC-CMs) or directly reprogrammed from non-myocytes (induced cardiomyocytes iCMs) are promising sources for heart regeneration or disease ...modeling. However, the similarities and differences between iPSC-CMs and iCMs are still unknown. Here, we performed transcriptome analyses of beating iPSC-CMs and iCMs generated from cardiac fibroblasts (CFs) of the same origin. Although both iPSC-CMs and iCMs establish CM-like molecular features globally, iPSC-CMs exhibit a relatively hyperdynamic epigenetic status, whereas iCMs exhibit a maturation status that more closely resembles that of adult CMs. Based on gene expression of metabolic enzymes, iPSC-CMs primarily employ glycolysis, whereas iCMs utilize fatty acid oxidation as the main pathway. Importantly, iPSC-CMs and iCMs exhibit different cell-cycle status, alteration of which influenced their maturation. Therefore, our study provides a foundation for understanding the pros and cons of different reprogramming approaches.
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•Gene expression profiling of iPSC-CMs and iCMs derived from CF of the same origin•Comparative analyses revealed distinct molecular features between iPSC-CMs and iCMs•iPSC-CMs and iCMs differ in gene signature of cell cycle, metabolism, and chromatin status•iCMs more closely resemble adult CMs when compared to iPSC-CMs
Zhou et al. performed gene expression profiling of cardiomyocytes derived from induced pluripotent stem cells (iPSC-CMs) or generated through direct reprogramming (induced cardiomyocytes iCMs) from cardiac fibroblasts of the same origin. Comparative analyses revealed similarities and differences in the molecular signatures of iPSC-CMs and iCMs.
Cemented paste backfill (CPB) is widely used in underground mining, and attracts more attention these years as it can reduce mining waste and avoid environmental pollution. Normally, to evaluate the ...functionality of CPB, the compressive strength (UCS) is necessary work, which is also time and money consuming. To address this issue, seven machine learning models were applied and evaluated in this study, in order to predict the UCS of CPB. In the laboratory, a series of tests were performed, and the dataset was constructed considering five key influencing variables, such as the tailings to cement ratio, curing time, solids to cement ratio, fine sand percentage and cement types. The results show that different variables have various effects on the strength of CPB. The optimum models for predicting the UCS of CPB are a support vector machine (SVM), decision tree (DT), random forest (RF) and back-propagation neural network (BPNN), which means that these models can be directly applied for UCS prediction in future work. Furthermore, the intelligent model reveals that the tailings to cement ratio has the most important influence on the strength of CPB. This research can boost CPB application in the field, and guide the artificial intelligence application in future mining.
A three-dimensional dynamic integer tent map is proposed which is based on one-dimensional and two-dimensional integer tent maps, and the effects of dimension, accuracy and disturbance on the chaotic ...map system are studied. Experiments show that this system can quickly generate multiple integer pseudo-random sequences that are independent of each other and distributed uniformly, so that the problem of accuracy loss due to the integer real number model and the problem of insufficient independence and uniformity of a multi-dimensional model are solved. According to the characteristics of three-dimensional map systems, a color image encryption algorithm is designed and its performance is analyzed from different aspects.
Fumarate hydratase-deficient renal cell carcinoma (FH-deficient RCC) is a rare but lethal subtype of RCC. Little is known about the genomic profile of FH-deficient RCC, and the therapeutic options ...for advanced disease are limited. To this end, we performed a comprehensive genomics study to characterize the genomic and epigenomic features of FH-deficient RCC.
Integrated genomic, epigenomic, and molecular analyses were performed on 25 untreated primary FH-deficient RCCs. Complete clinicopathologic and follow-up data of these patients were recorded.
We identified that FH-deficient RCC manifested low somatic mutation burden (median 0.58 mutations per megabase), but with frequent somatic copy-number alterations. The majority of FH-deficient RCCs were characterized by a CpG sites island methylator phenotype, displaying concerted hypermethylation at numerous CpG sites in genes of transcription factors, tumor suppressors, and tumor hallmark pathways. However, a few cases (20%) with low metastatic potential showed relatively low DNA methylation levels, indicating the heterogeneity of methylation pattern in FH-deficient RCC. Moreover, FH-deficient RCC is potentially highly immunogenic, characterized by increased tumor T-cell infiltration but high expression of immune checkpoint molecules in tumors. Clinical data further demonstrated that patients receiving immune checkpoint blockade-based treatment achieved improved progression-free survival over those treated with antiangiogenic monotherapy (median, 13.3 vs. 5.1 months;
= 0.03).
These results reveal the genomic features and provide new insight into potential therapeutic strategies for FH-deficient RCC.
Congenital heart disease often features structural abnormalities that emerge during development. Accumulating evidence indicates a crucial role for cardiac contraction and the resulting fluid forces ...in shaping the heart, yet the molecular basis of this function is largely unknown. Using the zebrafish as a model of early heart development, we investigated the role of cardiac contraction in chamber maturation, focusing on the formation of muscular protrusions called trabeculae. By genetic and pharmacological ablation of cardiac contraction, we showed that cardiac contraction is required for trabeculation through its role in regulating notch1b transcription in the ventricular endocardium. We also showed that Notch1 activation induces expression of ephrin b2a (efnb2a) and neuregulin 1 (nrg1) in the endocardium to promote trabeculation and that forced Notch activation in the absence of cardiac contraction rescues efnb2a and nrg1 expression. Using in vitro and in vivo systems, we showed that primary cilia are important mediators of fluid flow to stimulate Notch expression. Together, our findings describe an essential role for cardiac contraction-responsive transcriptional changes in endocardial cells to regulate cardiac chamber maturation.
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