Key points
In a cold environment, mammals increase their food intake while fish decrease or stop feeding. However, the physiological value of fasting during cold resistance in fish is currently ...unknown.
Fasting for more than 48 h enhanced acute cold resistance in zebrafish, which correlated with lipid catabolism and cell damage attenuation.
Lipid catabolism and autophagy were necessary for cold resistance in fish and the inhibition of mitochondrial fatty acid β‐oxidation or autophagy weakened the fasting‐induced cold resistance.
Repression of mechanistic target of rapamycin (mTOR) signalling pathway by rapamycin largely mimicked the beneficial effects of fasting in promoting cold resistance, suggesting mTOR signalling may be involved in the fasting‐induced cold resistance in fish.
Our study demonstrates that fasting may be a protective strategy for fish to survive under cold stress.
In cold environments, most homeothermic animals increase their food intake to supply more energy to maintain body temperature, whereas most poikilothermic animals such as fishes decrease or even stop feeding under cold stress. However, the physiological value of fasting during cold resistance in poikilotherms has not been explained. Here, we show that moderate fasting largely enhanced cold resistance in fish. By using pharmacological (fenofibrate, mildronate, chloroquine and rapamycin) and nutritional approaches (fatty acids diets and amino acids diets) in wild‐type or specific gene knock‐out zebrafish models (carnitine palmitoyltransferase‐1b‐deficient strain, CPT1b−/−, or autophagy‐related protein 12‐deficient strain, ATG12−/−), we verified that fasting‐stimulated lipid catabolism and autophagy played essential roles in the improved cold resistance. Moreover, suppression of the mechanistic target of rapamycin (mTOR) pathway by using rapamycin mostly mimicked the beneficial effects of fasting in promoting cold resistance as either the physiological phenotype or transcriptomic pattern. However, these beneficial effects were largely reduced when the mTOR pathway was activated through high dietary leucine supplementation. We conclude that fasting helps fish to resist cold stress by modulating lipid catabolism and autophagy, which correlates with the mTOR signalling pathway. Therefore, fasting can act as a protective strategy of fish in resisting coldness.
Key points
In a cold environment, mammals increase their food intake while fish decrease or stop feeding. However, the physiological value of fasting during cold resistance in fish is currently unknown.
Fasting for more than 48 h enhanced acute cold resistance in zebrafish, which correlated with lipid catabolism and cell damage attenuation.
Lipid catabolism and autophagy were necessary for cold resistance in fish and the inhibition of mitochondrial fatty acid β‐oxidation or autophagy weakened the fasting‐induced cold resistance.
Repression of mechanistic target of rapamycin (mTOR) signalling pathway by rapamycin largely mimicked the beneficial effects of fasting in promoting cold resistance, suggesting mTOR signalling may be involved in the fasting‐induced cold resistance in fish.
Our study demonstrates that fasting may be a protective strategy for fish to survive under cold stress.
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Cancer-derived exosomes are considered a major driver of cancer-induced pre-metastatic niche formation at foreign sites, but the mechanisms remain unclear. Here, we show that miR-25-3p, a ...metastasis-promoting miRNA of colorectal cancer (CRC), can be transferred from CRC cells to endothelial cells via exosomes. Exosomal miR-25-3p regulates the expression of VEGFR2, ZO-1, occludin and Claudin5 in endothelial cells by targeting KLF2 and KLF4, consequently promotes vascular permeability and angiogenesis. In addition, exosomal miR-25-3p from CRC cells dramatically induces vascular leakiness and enhances CRC metastasis in liver and lung of mice. Moreover, the expression level of miR-25-3p from circulating exosomes is significantly higher in CRC patients with metastasis than those without metastasis. Our work suggests that exosomal miR-25-3p is involved in pre-metastatic niche formation and may be used as a blood-based biomarker for CRC metastasis.
Hybrid organic–inorganic perovskite materials garner enormous attention for a wide range of optoelectronic devices. Due to their attractive optical and electrical properties including high optical ...absorption coefficient, high carrier mobility, and long carrier diffusion length, perovskites have opened up a great opportunity for high performance photodetectors. This review aims to give a comprehensive summary of the significant results on perovskite‐based photodetectors, focusing on the relationship among the perovskite structures, device configurations, and photodetecting performances. An introduction of recent progress in various perovskite structure‐based photodetectors is provided. The emphasis is placed on the correlation between the perovskite structure and the device performance. Next, recent developments of bandgap‐tunable perovskite and hybrid photodetectors built from perovskite heterostructures are highlighted. Then, effective approaches to enhance the stability of perovskite photodetector are presented, followed by the introduction of flexible and self‐powered perovskite photodetectors. Finally, a summary of the previous results is given, and the major challenges that need to be addressed in the future are outlined. A comprehensive summary of the research status on perovskite photodetectors is hoped to push forward the development of this field.
Hybrid organic–inorganic perovskite materials have attracted wide research interests owing to their unique electrical and optoelectronic properties. This Review provides a profound summary of the most important works on perovskite photodetectors, and gives a systematic discussion on the advantages and disadvantages of different device configurations and perovskite morphologies, as well as future directions.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
The High Resolution Model Intercomparison Project (HighResMIP) experiment within the Coupled Model Intercomparison Project Phase 6 (CMIP6), for the first time, has provided an opportunity to evaluate ...the performance of climate models over complex topographies. Based on the HighResMIP's historical simulations of atmospheric general circulation models, the performances of global high-resolution models, with a horizontal resolution finer than 50 km, in representing precipitation over Central Asia were evaluated using rain gauge observation datasets. All the models successfully reproduce the large precipitation regions that are located over the mountainous areas and Northern Central Asia. However, nearly all the models overestimate precipitation frequency over Central Asia and large overestimations of precipitation amount and frequency are located over the mountainous areas. Although the HighResMIP multi-model ensemble mean performs better than all individual models at simulating the spatial pattern of precipitation frequency, it is inferior to HadGEM3-GC31-HM and ECMWF-IFS-HR at simulating that of precipitation amount. The simulation performance exhibits remarkable regional differences. Over the Qilian Mountains, the relationship between precipitation and elevation is totally captured by climate models. In contrast, over the Tianshan Mountains, the models fail to simulate the decrease in precipitation frequency after elevation higher than the maximum precipitation elevation. Most models successfully reproduce the annual cycle shape of precipitation amount over the Southern Central Asia, Qilian Mountains and Tianshan Mountains, but fail to reproduce it over the Northern Central Asia. More than half of the high-resolution GCMs have a reduced bias relative to the corresponding low-resolution GCMs. The performances of most high-resolution GCMs in simulating precipitation pattern are well over the Tianshan Mountains.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Abstract
After the first quasiperiodic eruption (QPE; GSN 069) was reported in 2019, four other sources have been identified as a QPE or a candidate. However, the physics behind QPEs is still ...unclear, although several models have been proposed. Pan et al. proposed an instability model for an accretion disk with magnetically driven outflows in the first QPE of GSN 069, which is able to reproduce both the light curve and the evolution of the spectra fairly well. In this work, we extend this model to all QPEs. We improve the calculations of the spectrum of the disk by introducing a hardening factor, which is caused by a deviation of opacity from a blackbody. We find that the light curves and evolution of the spectra of the four QPEs and candidates can all be well reproduced by our model calculations.
We report a solution-chemistry-based approach to large, stable colloidal graphene quantum dots with uniform size and shape. The versatility of solution chemistry allows us to tune the structures of ...the graphenes and thus their properties.
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IJS, KILJ, NUK, PNG, UL, UM
CdS nanostructures have received much attention in recent years as building blocks for optoelectronic devices due to their unique physical and chemical properties. This progress report provides an ...overview of recent research about rational design of CdS nanoscale photodetectors. Three kinds of photodetectors according to the metal‐semiconductor contact types are discussed in detail: Ohmic contact, Schottky contact, and field enhanced transistor configuration. The focus is on the tuning of optical and electrical properties CdS nanostructures by element doping, composition and bandgap engineering, and heterojunction integration, along with thus modified device performances generated during these tuning processes. Latest concepts of photodetector design such as flexible, self‐powered, plasmonic, and piezophototronic photodetectors with novel properties are introduced to demonstrate the future directions of such an exciting research field.
Recent advances of CdS nanoscale photodetectors with Ohmic contact, Schottky contact and MESFET configuration are summarized. Element doping, composition and bandgap engineering, heterojunction integration, and new design concepts in photodetectors are discussed. Future development directions are also discussed.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Land surface temperature (LST) is a crucial parameter that reflects land–atmosphere interaction and has thus attracted wide interest from geoscientists. Owing to the rapid development of Earth ...observation technologies, remotely sensed LST is playing an increasingly essential role in various fields. This review aims to summarize the progress in LST estimation algorithms and accelerate its further applications. Thus, we briefly review the most‐used thermal infrared (TIR) LST estimation algorithms. More importantly, this review provides a comprehensive collection of the widely used TIR‐based LST products and offers important insights into the uncertainties in these products with respect to different land cover conditions via a systematic intercomparison analysis of several representative products. In addition to the discussion on product accuracy, we address problems related to the spatial discontinuity, spatiotemporal incomparability, and short time span of current LST products by introducing the most effective methods. With the aim of overcoming these challenges in available LST products, much progress has been made in developing spatiotemporal seamless LST data, which significantly promotes the successful applications of these products in the field of surface evapotranspiration and soil moisture estimation, agriculture drought monitoring, thermal environment monitoring, thermal anomaly monitoring, and climate change. Overall, this review encompasses the most recent advances in TIR‐based LST and the state‐of‐the‐art of applications of LST products at various spatial and temporal scales, identifies critical further research needs and directions to advance and optimize retrieval methods, and promotes the application of LST to improve the understanding of surface thermal dynamics and exchanges.
Plain Language Summary
Land surface temperature (LST) is a crucial geophysical parameter related to surface energy and water balance of the land‐atmosphere system. Satellite remote sensing provides the best way to measure LST and generate various LST products at regional and global scales. In this review, to facilitate the application of LST products in different fields, we first present the physical meaning of satellite‐derived LST. Subsequently, we summarize recent advances in LST retrieval and validation methods, with a special focus on the state‐of‐the‐art product collections, product accuracies and intercomparisons, and main problems in current LST products as well as their possible solutions. Additionally, we also review the major applications of LST products in agricultural drought monitoring, thermal environment monitoring, thermal anomaly monitoring, and climate change. Finally, we offer recommendations or perspectives to promote LST retrieval methods and their applications. This review will aid the user in gaining a thorough comprehensive understanding of satellite‐derived LST products and promoting their appropriate applications.
Key Points
State‐of‐the‐art satellite‐derived land surface temperature (LST) product levels, sources, uncertainties, and differences are provided
Typical applications of LST products in various fields are summarized
Future directions for the generation and applications of LST products are recommended
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Land surface temperatures (LSTs) at high spatial resolution are crucial for hydrological, meteorological, and ecological studies. Downscaling LSTs from coarse resolution to finer resolution is an ...alternative way to obtain LSTs at high spatial resolution. In this paper, we proposed a new algorithm based on geographically weighted regression (GWR) to downscale Moderate Resolution Imaging Spectroradiometer LST data from 990 to 90 m. Unlike previous LST downscaling algorithms, this algorithm built the nonstationary relationship between LST and other environmental factors (including the normalized difference vegetation index and a digital elevation model) using geographically varying regression coefficients. The uncertainty in this algorithm was evaluated with a sensitivity analysis. The results show that the total uncertainty in this algorithm is less than 2 K. The performance of the GWR-based algorithm was assessed using concurrent ASTER LST data as a reference LST data set. Moreover, this algorithm was compared against the TsHARP algorithm, which was widely used for LST downscaling. The results indicate that the GWR-based algorithm outperforms the TsHARP algorithm in terms of statistical results. The root mean square error (mean absolute error) value decreases from 3.6 K (2.7 K) for the TsHARP algorithm to 3.1 K (2.3 K) for the GWR-based algorithm.
The radical-involved 1,2-difunctionalization of alkenes has developed into a robust tool for preparation of complex organic molecules. Despite significant advances in this area, the catalytic ...asymmetric version still remains a challenging task mainly due to the difficulty in the stereocontrol of the highly reactive radical intermediates. Recently, owing to the good single-electron transfer ability and coordination with chiral ligands of copper catalysts, remarkable achievements in radical-involved asymmetric alkene difunctionalization have been made
via
synergistic combination of copper and chiral ligands. This tutorial review highlights the recent progress in copper-catalysed radical-involved asymmetric 1,2-difunctionalization of alkenes and the mechanistic scenarios governing the stereocontrol, with an emphasis on utilization of chiral ligands.
This tutorial review highlights the recent progress in copper-catalysed radical asymmetric 1,2-difunctionalization of alkenes.
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