Abstract
Dust cycle is actively involved in the Earth’s climate and environmental systems. However, the spatiotemporal pattern and recent trend of dust emission from the drylands in East Asia remain ...unclear. By calculating dust aerosol optical depth (DOD) from the newly released moderate resolution imaging spectrometer aerosol products, we obtain a relatively long satellite-based time series of dust activity from 2001 to 2020 over China and Mongolia. We identify pronounced interannual variability of dust activity that is consistent with ground-based meteorological observations in the study area. A substantial reduction in spring dust activity in northern China is also found, which seems in accordance with the long-term weakening trend since the 1970s that has been attributed to the wind speed decline by previous studies. However, the spatial pattern of the trends in both annual mean and seasonal dust activity during the last 20 years is divergent, and the most significant dust diminishing is found over north-central China where large-scale vegetation restoration projects have been implemented. It indicates that in addition to the potential contribution of wind speed change, land-use change also plays an important role in the recent inhibition of dust emission. The current results show that dust activity occurs most intensively in spring, followed by summer and relatively weaker in autumn and winter. However, dust activity in autumn and winter has increased significantly in NW China despite the overall decreasing trend in other two seasons, probably associated with different seasonal atmospheric and land surface conditions. Finally, the DOD distribution reveals that the Tarim Basin, Gobi and Qaidam Basin Deserts are three major dust sources in East Asia. Compared to ground observations which are spatially limited and distributed unevenly, remote sensing provides an important complement, and it can serve as reference for identification of dust sources using other methods such as geochemical fingerprint and modeling.
With dramatic changes in lifestyles over the last 20 years, nonalcoholic fatty liver disease (NAFLD) has become the most prevalent liver disorder in China but has not received sufficient attention. ...NAFLD‐related advanced liver disease and its mortality along with its overall disease burden are expected to increase substantially. There is thus an imperative need to clarify the epidemiological features of NAFLD to guide a holistic approach to management. We summarize eight epidemiological features of NAFLD in China over the past two decades using systematic review and meta‐analysis methodology. Our data reveal a rapid growth in the NAFLD population, especially among younger individuals. Importantly, there is a strong ethnic difference in body mass index (BMI) and genetic risk of NAFLD compared with the US population. The etiology of advanced liver disease and its complications (e.g., hepatocellular carcinoma) has been altered because of a Westernized lifestyle and the implementation of effective vaccination strategies against viral hepatitis. Regional epidemiological patterns of NAFLD indicate that economics, environment, and lifestyle are critical factors in disease progression. The analysis also indicates that a large number of patients remain undiagnosed and untreated because of the inadequacy of diagnostic tools and the absence of effective pharmacologic therapies. Given the burden of NAFLD, future policy and research efforts need to address knowledge gaps to mitigate the risk burden.
With rapid lifestyle transitions, the increasing burden of nonalcoholic fatty liver disease (NAFLD) in China has emerged as a major public health issue. To obtain a comprehensive overview of the ...status of NAFLD over the past decade, we evaluated the epidemiology, risk factors, complications, and management of NAFLD in China through a systematic review and meta‐analysis. Five English literature databases and three Chinese databases were searched for relevant topics from 2008 to 2018. A total of 392 studies with a population of 2,054,554 were included. National prevalence of NAFLD was 29.2%, with a heavier disease burden among the middle‐aged, males, those in northwest China and Taiwan, regions with a gross domestic product per capita greater than 100,000 yuan, and Uygur and Hui ethnic groups. Currently, original studies on natural history and complications of NAFLD in China are scarce. Several studies revealed that NAFLD is positively correlated with the incidence of extrahepatic tumors, diabetes, cardiovascular disease and metabolic syndrome. The Chinese population may have a higher hereditary risk of NAFLD due to more frequent nonsynonymous mutations in genes regulating lipid metabolism. Ultrasonography is the primary imaging tool in the detection of NAFLD in China. Serum tests and risk stratification algorithms for staging NAFLD remain under investigation. Specific pharmaceutical treatments for NAFLD are still undergoing clinical trials. It is noteworthy that the Chinese are underrepresented compared with their proportion of the NAFLD population in such trials. Conclusion: China experienced an unexpected rapid increase in the burden of NAFLD over a short period. Rising awareness and urgent actions need to be taken in order to control the NAFLD pandemic in China.
Hepatocytes has been confirmed to undergo EMT and can be converted into myofibroblasts during hepatic fibrogenesis. However, the mechanism of hepatocyte EMT regulation in hepatic fibrosis, ...particularly through HSP27 (human homologue of rodent HSP25), remains unclear. Mangiferin (MAN), a compound extracted from Mangifera indica L, has been reported to attenuate liver injury. This study aimed to investigate the mechanisms underlying HSP27 inhibition and the anti‐fibrotic effect of MAN in liver fibrosis. Our results revealed that the expression of HSP27 was remarkably increased in the liver tissues of patients with liver cirrhosis and CCl4‐induced fibrotic rats. However, HSP27 shRNA treatment significantly alleviated fibrosis. Furthermore, MAN was found to inhibit CCl4‐ and TGF‐β1‐induced liver fibrosis and reduced hepatocyte EMT. More importantly, MAN decreased HSP27 expression to suppress the JAK2/STAT3 pathway, and subsequently blocked TGF‐β1/Smad signaling, which were consistent with its protection against CCl4‐induced EMT and liver fibrosis. Together, these results suggest that HSP27 may play a crucial role in hepatocyte EMT and liver fibrosis by activating JAK2/STAT3 signaling and TGF‐β1/Smad pathway. The suppression of HSP27 expression by MAN may be a novel strategy for attenuating the hepatocyte EMT in liver fibrosis.
Thermal barrier coatings (TBCs) can effectively protect the alloy substrate of hot components in aeroengines or land-based gas turbines by the thermal insulation and corrosion/erosion resistance of ...the ceramic top coat. However, the continuous pursuit of a higher operating temperature leads to degradation, delamination, and premature failure of the top coat. Both new ceramic materials and new coating structures must be developed to meet the demand for future advanced TBC systems. In this paper, the latest progress of some new ceramic materials is first reviewed. Then, a comprehensive spalling mechanism of the ceramic top coat is summarized to understand the dependence of lifetime on various factors such as oxidation scale growth, ceramic sintering, erosion, and calcium-magnesium-aluminium-silicate (CMAS) molten salt corrosion. Finally, new structural design methods for high-performance TBCs are discussed from the perspectives of lamellar, columnar, and nanostructure inclusions. The latest developments of ceramic top coat will be presented in terms of material selection, structural design, and failure mechanism, and the comprehensive guidance will be provided for the development of next-generation advanced TBCs with higher temperature resistance, better thermal insulation, and longer lifetime.
Background and Aims
Hepatic ischemia‐reperfusion (IR) injury is a major complication of liver transplantation, resection, and hemorrhagic shock. Hypoxia is a key pathological event associated with IR ...injury. MicroRNA‐210 (miR‐210) has been characterized as a micromanager of hypoxia pathway. However, its function and mechanism in hepatic IR injury is unknown.
Approach and Results
In this study, we found miR‐210 was induced in liver tissues from patients subjected to IR‐related surgeries. In a murine model of hepatic IR, the level of miR‐210 was increased in hepatocytes but not in nonparenchymal cells. miR‐210 deficiency remarkably alleviated liver injury, cell inflammatory responses, and cell death in a mouse hepatic IR model. In vitro, inhibition of miR‐210 decreased hypoxia/reoxygenation (HR)–induced cell apoptosis of primary hepatocytes and LO2 cells, whereas overexpression of miR‐210 increased cells apoptosis during HR. Mechanistically, miR‐210 directly suppressed mothers against decapentaplegic homolog 4 (SMAD4) expression under normoxia and hypoxia condition by directly binding to the 3′ UTR of SMAD4. The pro‐apoptotic effect of miR‐210 was alleviated by SMAD4, whereas short hairpin SMAD4 abrogated the anti‐apoptotic role of miR‐210 inhibition in primary hepatocytes. Further studies demonstrated that hypoxia‐induced SMAD4 transported into nucleus, in which SMAD4 directly bound to the promoter of miR‐210 and transcriptionally induced miR‐210, thus forming a negative feedback loop with miR‐210.
Conclusions
Our study implicates a crucial role of miR‐210‐SMAD4 interaction in hepatic IR‐induced cell death and provides a promising therapeutic approach for liver IR injury.
ObjectiveType 2 diabetes mellitus is increasing in young adults, and greater adiposity is considered a major risk factor. However, whether there is an association between obesity and diabetes and how ...this might be impacted by age is not clear. Therefore, we investigated the association between body mass index (BMI) and diabetes across a wide range of age groups (20–30, 30–40, 40–50, 50–60, 60–70 and ≥70 years old).DesignWe performed a retrospective cohort study using healthy screening programme data.SettingA total of 211 833 adult Chinese persons >20 years old across 32 sites and 11 cities in China (Shanghai, Beijing, Nanjing, Suzhou, Shenzhen, Changzhou, Chengdu, Guangzhou, Hefei, Wuhan, Nantong) were selected for the study; these persons were free of diabetes at baseline.Primary and secondary outcome measuresFasting plasma glucose levels were measured and information regarding the history of diabetes was collected at each visit. Diabetes was diagnosed as fasting plasma glucose ≥7.00 mmol/L and/or self-reported diabetes. Patients were censored at the date of diagnosis or the final visit, whichever came first.ResultsWith a median follow-up of 3.1 years, 4174 of the 211 833 participants developed diabetes, with an age-adjusted incidence rate of 7.35 per 1000 persons. The risk of incident diabetes increased proportionally with increasing baseline BMI values, with a 23% increased risk of incident diabetes with each kg/m2 increase in BMI (95% CI 1.22 to 1.24). Across all age groups, there was a linear association between BMI and the risk of incident diabetes, although there was a stronger association between BMI and incident diabetes in the younger age groups (age×BMI interaction, p<0.0001).ConclusionsAn increased BMI is also independently associated with a higher risk of developing diabetes in young adults and the effects of BMI on incident diabetes were accentuated in younger adults.
Inflammation and metabolic dysfunction are hallmarks of nonalcoholic steatohepatitis (NASH), which is one of the fastest‐growing liver diseases worldwide. Emerging evidence indicates that innate ...immune mechanisms are pivotal drivers of inflammation and other pathological manifestations observed in NASH, such as hepatosteatosis, insulin resistance (IR), and fibrosis. This robust innate immune reaction is intrinsic to the liver, which is an important immunological organ that contains a coordinated network of innate immune cells, including Kupffer cells (KCs), dendritic cells (DCs), and lymphocytes. Hepatocytes and liver sinusoidal endothelial cells (LSECs) are not formally innate immune cells, but they take on immune cell function when stressed. These cells can sense excess metabolites and bacterial products and translate those signals into immune responses and pathological hepatic changes during the development of NASH. In this review, we take a historical perspective in describing decades of research that aimed to identify the key molecular and cellular players in the innate immune system in the setting of NASH. Furthermore, we summarize the innate immune cells that are involved in the progression of NASH and illustrate how they sense disturbances in circulating metabolic factors by innate immune receptors and subsequently initiate the intercellular signaling cascades that lead to persistent inflammation and progression of hepatic complications.
Abstract
Higher-order correlated excitonic states arise from the mutual interactions of excitons, which generally requires a significant exciton density and therefore high excitation levels. Here, we ...report the emergence of two biexcitons species, one neutral and one charged, in monolayer tungsten diselenide under moderate continuous-wave excitation. The efficient formation of biexcitons is facilitated by the long lifetime of the dark exciton state associated with a spin-forbidden transition, as well as improved sample quality from encapsulation between hexagonal boron nitride layers. From studies of the polarization and magnetic field dependence of the neutral biexciton, we conclude that this species is composed of a bright and a dark excitons residing in opposite valleys in momentum space. Our observations demonstrate that the distinctive features associated with biexciton states can be accessed at low light intensities and excitation densities.
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