A stronger than global mean warming trend is projected over Central Asia in the coming century. Based on the historical simulations and projections under four combined scenarios of the Shared ...Socioeconomic Pathways and the Representative Concentration Pathways (SSP1-2.6, SSP2-4.5, SSP3-7.0 and SSP5-8.5) provided by 15 models from the Sixth Phase of Coupled Model Intercomparison Project (CMIP6), we show a comprehensive picture of the future changes in precipitation over Central Asia under rapid warming and investigate possible mechanisms. At the end of the twenty-first century, robust increase of annual mean precipitation under all the scenarios is found (4.23 2.60 to 7.36 %, 10.52 5.05 to 13.36 %, 14.51 8.11 to 16.91 %, 14.41 9.58 to 21.26 % relative to the present-day for SSP1-2.6, SSP2-4.5, SSP3-7.0 and SSP5-8.5, respectively). The response of precipitation to increasing global mean temperature shows similar spatial patterns for the four scenarios with stronger changes over Tianshan mountain and the northern part of Central Asia. Further analysis reveals a wetting trend in spring and a drying trend in summer in both the north of Central Asia (NCA) and south of Central Asia (SCA). The wetting trend in spring is balanced by the increase of evaporation, while the drying trend in summer is mainly contributed by the decrease of vertical moisture advection. The thermodynamic effects associated with humidity changes contribute to the drying trends in both the two domains, while the dynamic effects favor for the drying trend in NCA and offset the drying trend in SCA. The response of precipitation to increasing temperature results in enhanced seasonalities for SCA and NCA, and an advancing of the first peak from summer to spring in the NCA.
Sulforaphane (SFN) is abundant in cruciferous plants, providing significant protection against many chronic diseases. With the aim of clarifying the efficacy of sulforaphane in diabetic retinopathy ...(DR), a series of systematic studies were carried out in the present study. Male Sprague Dawley rats were intraperitoneally injected with streptozotocin (STZ, 65 mg/kg), and those with confirmed diabetes mellitus were given different doses of SFN (0.5 and 1 mg/kg/d) for 12 weeks. In vitro, Müller cells exposed to 25 mM glucose were treated with 2.5 µM SFN. The results indicated that SFN significantly reduced the generation of pro-inflammatory cytokines (TNF-α, IL-6, and IL-1β) and enhanced the activity of antioxidant enzymes (GSH, SOD, and CAT) in the retina of STZ rats. Further, SFN enhanced the nuclear accumulation of Nrf2 and increased the expression of HO-1 and NQO1, two major antioxidants downstream to Nrf2, in the injured retina. In addition, retinal expression levels of NLRP3, cleaved caspase-1 p20, IL-1β p17, and ASC were dramatically increased in STZ-induced DR, and this was abolished by SFN intervention. In vitro, high glucose-induced inflammation and oxidative stress damage in Müller cells were attenuated by SFN. SFN also exerted antioxidant effects, activated the Nrf2 pathway, and inhibited the NLRP3 inflammasome in Müller cells. In conclusion, our work demonstrates that SFN attenuates retinal inflammation and oxidative stress induced by high glucose and activates the antioxidative Nrf2 pathway and inhibits the formation of the NLRP3 inflammasome in vivo and in vitro.
The Yangtze River valley (YRV), located in central-eastern China, has witnessed increased numbers of heat waves in the summer since 1951. Knowing what factors control and affect the interannual ...variability of heat waves, especially distinguishing the contributions of anomalous sea surface temperature (SST) forcings and those of internal modes of variability, is important to improving heat wave prediction. After evaluating 70 members of the atmospheric model intercomparison project (AMIP) experiments from the 25 models that participated in the coupled model intercomparison project phase 5 (CMIP5), 13 high-skill members (HSMs) are selected to estimate the SST-forced variability. The results show that approximately 2/3 of the total variability of the July–August heat waves in the YRV during 1979–2008 can be attributed to anomalous SST forcings, whereas the other 1/3 are due to internal variability. Within the SST-forced component, one-half of the influence is from the impact of the El Niño–Southern Oscillation (ENSO) and the other half is from non-ENSO related SST forcings, specifically, the SST anomalies in the North Pacific and the North Atlantic. Both the decaying El Niño and developing La Niña accompanied by a warm Indian Ocean and cold central Pacific, respectively, are favorable to hotter summers in the YRV because these patterns strengthen and extend the western North Pacific Subtropical High (WNPSH) westwards, for which the decaying ENSO plays a dominant role. The internal variability shows a circumglobal teleconnection in which Rossby waves propagate southeastwards over the Eurasian Continent and strengthen the WNPSH. Atmospheric model sensitivity experiments confirm that non-ENSO SST forcings can modulate the WNPSH and heat wave variability by projecting their influences onto the internal mode.
Long-time coherent integration technique is one of the most important methods for the improvement of radar detection ability of a weak maneuvering target, whereas the integration performance may be ...greatly influenced by the across range unit (ARU) and Doppler frequency migration (DFM) effects. In this paper, a novel representation known as Radon-fractional Fourier transform (RFRFT) is proposed and investigated to solve the above problems simultaneously. It can not only eliminate the effect of DFM by selecting a proper rotation angle but also achieve long-time coherent integration without ARU effect. The RFRFT can be regarded as a special Doppler filter bank composed of filters with different rotation angles, which indicates a generalization of the traditional moving target detection (MTD) and FRFT methods. Some useful properties and the likelihood ratio test detector of RFRFT are derived for maneuvering target detection. Finally, numerical experiments of aerial target and marine target detection are carried out using simulated and real radar datasets. The results demonstrate that for integration gain and detection ability, the proposed method is superior to MTD, FRFT, and Radon-Fourier transform under low signal-to-clutter/noise ratio (SCR/SNR) environments. Moreover, the trajectory of target can be easily obtained via RFRFT as well.
Changes in global land monsoon (GLM) precipitation determine the local water resource, affecting two thirds of global population. The future changes in GLM summer precipitation and the sources of ...projection uncertainty under four scenarios are investigated using the Coupled Model Intercomparison Project Phase 6 (CMIP6) models. The GLM summer precipitation is projected to increase by 1.76 ± 1.57% (2.54 ± 2.22%), 1.33 ± 1.97% (3.52 ± 3.05%), 0.96 ± 2.04% (3.51 ± 4.97%), and 1.71 ± 2.38% (5.75 ± 5.92%) in the near (long) term under Shared Socioeconomic Pathway (SSP) 1–2.6, SSP2–4.5, SSP3–7.0, and SSP5–8.5, respectively. The enhancement is caused by thermodynamic responses due to increased moisture, which is partly offset by dynamic responses due to weakened circulation. The uncertainty in GLM precipitation projection is the largest in SSP5–8.5 long‐term projection. The uncertainty of submonsoon precipitation projections is larger than that in GLM precipitation. The uncertainty of monsoon precipitation projection arises from the circulation changes, which can be partly explained by model‐dependent response to uniform sea surface temperature warming.
Plain Language Summary
The changes of monsoon rainfall under a warmer climate receive much attention. Here we revealed the future changes of summer precipitation over global and submonsoon regions in different periods under four new scenarios designed by the Coupled Model Intercomparison Project Phase 6 (CMIP6). In 2021–2040 (2080–2099), the monsoon summer rainfall will increase by about 1.76 ± 1.57% (2.54 ± 2.22%), 1.33 ± 1.97% (3.52 ± 3.05%), 0.96 ± 2.04% (3.51 ± 4.97%), and 1.71 ± 2.38% (5.75 ± 5.92%) under the low, medium, and two high emission scenarios, respectively. At the end of the 21st century, the monsoon rainfall will increase largest in the highest emission scenario with largest spread. Moreover, the spread over each submonsoon region is much larger than that of global land monsoon. The increase of rainfall is associated with the increase of water vapor but offset by the weakened circulation. The spread of rainfall changes is caused by the spread of circulation projection, which is partly caused by the model‐dependent responses of circulation to uniform sea surface temperature warming.
Key Points
Global land monsoon precipitation increase is due to moisture increases, while the uncertainty is due to uncertainty of circulation changes
The uncertainty of circulation mainly comes from model spread in midterm and long‐term projections but from internal variability in near term
Model‐dependent response to uniform sea surface temperature warming is one of the uncertainty sources in land monsoon circulation projection
The Paris Agreement set a goal to keep global warming well below 2 °C and pursue efforts to limit it to 1.5 °C. Understanding how 0.5 °C less warming reduces impacts and risks is key for climate ...policies. Here, we show that both areal and population exposures to dangerous extreme precipitation events (e.g., once in 10- and 20-year events) would increase consistently with warming in the populous global land monsoon regions based on Coupled Model Intercomparison Project Phase 5 multimodel projections. The 0.5 °C less warming would reduce areal and population exposures to once-in-20-year extreme precipitation events by 25% (18-41%) and 36% (22-46%), respectively. The avoided impacts are more remarkable for more intense extremes. Among the monsoon subregions, South Africa is the most impacted, followed by South Asia and East Asia. Our results improve the understanding of future vulnerability to, and risk of, climate extremes, which is paramount for mitigation and adaptation activities for the global monsoon region where nearly two-thirds of the world's population lives.
Significant uncertainties in the projected South Asian summer monsoon (SASM) have been observed in the released Fifth Phase of the Coupled Model Intercomparison Project (CMIP5) data set. Knowing what ...factors dominate the uncertainties is critical to constraining the local climate changes. Analyzing state‐of‐the‐art climate model simulations under the RCP8.5 scenario, we find that uncertainties in the circulation primarily result from the divergent global mean warming across models. In contrast, the compensation between dynamic and thermodynamic effects makes the spread in monsoon rainfall independent of the global temperature change. Via a suite of sensitivity experiments, we identify that the uncertainties in the SASM rainfall are dominated by the Indo‐Pacific sea surface temperature (SST) warming pattern, especially around the western central Pacific. The SST warming pattern plays its role by changing the zonal temperature gradient over the SASM region and modulating the interhemispheric moisture transport. We highlight that the SST warming patterns require more attention in constraining the projected regional rainfall changes.
Key Points
Divergent global mean warming renders key uncertainty to the projected monsoon circulation
Indo‐Pacific warming patterns, not the mean warming, contribute to the rainfall spread in models
Monsoon rainfall spread is mainly controlled by the zonal gradient of tropospheric temperature
•Novel periodic expanded-constrained microchannels (PECM) heat sink was proposed.•Heat transfer enhancement was achieved for PECM without at the expense of pressure drop penalty.•Pressure drop of ...PECM increased monotonically with decreasing the microchannel gap widths.•Thermal resistance of PECM decreased with the increase in microchannel gap width.
Thermal management of high heat flux devices in many areas has promoted the development of advanced microchannel heat sinks. This study proposed a novel type of periodic expanded-constrained microchannels (PECM) heat sink with flow separation and convergence passages. Its convective heat transfer and pressure drop performance was explored by both experimental tests and numerical simulations, and its cooling efficiency was compared with rectangular microchannels. Forced convection tests were conducted at Reynolds number of 150–820 and two levels of heat fluxes using deionized water. Results indicated that the PECM samples showed significant heat transfer enhancement, i.e., 50% to 117%, compared to the rectangular counterpart in the test ranges. Such enhancement can be attributed to that the periodic expanded-constrained configurations of PECM induced periodic interruption and redevelopment of thermal and hydraulic boundary layers, as well as good flow separation, fluid acceleration and mixing. Moreover, the heat transfer enhancement of PECM was not accompanied with the expense of pressure drop penalty, and all the PECM samples reduced the pressure drop for 10–74% compared to the rectangular counterpart. Besides, the effect of microchannel gap width in the main flow passages on the thermal and hydraulic performance was also assessed by preparing three samples with microchannel gap widths of 0.5, 0.8 and 1.0 mm. It was found that the pressure drop and thermal resistance of PECM increased monotonically with decreasing the microchannel gap widths. The sample with the largest microchannel gap width of 1.0 mm presented the best overall thermal and hydraulic performance.
The long non-coding RNA PVT1 (lncRNA PVT1) has been reported to act as an oncogenic regulator of several cancers. However, its expression and function in gallbladder cancer (GBC) remain largely ...unknown.
In situ hybridization (ISH) and quantitative real-time PCR (qPCR) were performed to detect the expression of PVT1 and miR-143 in GBC tissues and cell lines. Immunohistochemistry (IHC) assays were performed to assess the expression of the hexokinase 2 (HK2) protein. The relationships among PVT1, miR-143 and HK2 were evaluated using dual-luciferase reporter, RNA immunoprecipitation (RIP) and biotin pull-down assays. The biological functions of PVT1, miR-143 and HK2 in GBC cells were explored with cell counting kit 8 (CCK-8), 5-ethynyl-20-deoxyuridine (EdU), colony formation, transwell, wound healing and glucose metabolism assays in vitro. For in vivo experiments, a xenograft model was used to investigate the effects of PVT1 and HK2 on GBC.
PVT1 was upregulated in GBC tissues and cells and was positively associated with malignancies and worse overall survival. PVT1 knockdown inhibited cell proliferation, migration, and invasion in vitro and restrained tumor growth in vivo. Further studies demonstrated that PVT1 positively regulated HK2 expression via its competing endogenous RNA (ceRNA) activity on miR-143. Additionally, HK2 expression and function were positively correlated with PVT1. Furthermore, we observed that the PVT1/miR-143/HK2 axis promoted cell proliferation and metastasis by regulating aerobic glucose metabolism in GBC cells.
The results of our study reveal a potential ceRNA regulatory pathway in which PVT1 modulates HK2 expression by competitively binding to endogenous miR-143 in GBC cells, which may provide new insights into novel molecular therapeutic targets for GBC.
The western North Pacific Subtropical High (WNPSH) is a key circulation system controlling the summer monsoon and typhoon activities over the western Pacific, but future projections of its changes ...remain hugely uncertain. Here we find two leading modes that account for nearly 80% intermodel spread in its future projection under a high emission scenario. They are linked to a cold-tongue-like bias in the central-eastern tropical Pacific and a warm bias beneath the marine stratocumulus, respectively. Observational constraints using sea surface temperature patterns reduce the uncertainties by 45% and indicate a robust intensification of the WNPSH due to suppressed warming in the western Pacific and enhanced land-sea thermal contrast, leading to 28% more rainfall projected in East China and 36% less rainfall in Southeast Asia than suggested by the multi-model mean. The intensification of the WNPSH implies more future monsoon rainfall and heatwaves but less typhoon landfalls over East Asia.
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