Aim
Climate change is expected to have important effects on plant phenology and carbon storage, with further shifts predicted in the future. Therefore, we proposed the community carbon accumulation ...rate (CAR) from the start of the growing season (SOS) to the peak of the growing season (POS) to fill the gap that the dynamic interactions between plant phenology and plant carbon research.
Location
Tibetan Plateau.
Major taxa
Alpine grassland plants.
Time period
2015.
Methods
We conducted a transect survey across grasslands to measure community aboveground net primary production and carbon concentration. Additionally, phenology indicator data (SOS and POS) were extracted from the Global Inventory Modeling and Mapping Studies (GIMMS) normalized difference vegetation index version 3 database. Next, we used ‘changepoint’ analysis to detect the patterns of CARs, and performed linear regression and one‐way ANOVA to explore the variability of CARs in response to the environmental factors. Ultimately, the total effects of environmental factors on CARs were illustrated by a structural equation model.
Results
Our results indicated that three CAR patterns were detected, which are low‐CAR (0.15 g/m2/day), medium‐CAR (0.31 g/m2/day) and high‐CAR (0.84 g/m2/day) patterns. We found that the availabilities of water and heat mediated CARs by regulating soil nutrition variability, and that drought climate and insufficient soil resources co‐constrained the community CAR at long time‐scales. In contrast, high CAR could be explained by more water and heat availability via either direct or indirect effects on soil moisture and soil nutrients.
Main conclusions
Our findings highlight that water and heat availability are critical driving factors in ecological carbon accumulation processes undergoing climate change. Meanwhile, the vegetative phenology also has important effect on carbon accumulation. Consequently, we propose incorporating the dynamic interactions between plant phenology and plant carbon into the ecological carbon cycle model to improve our understanding of resource utilization and survival strategies of plants under environmental change.
Understanding the dynamics and underlying mechanism of carbon exchange between terrestrial ecosystems and the atmosphere is one of the key issues in global change research. In this study, we ...quantified the carbon fluxes in different terrestrial ecosystems in China, and analyzed their spatial variation and environmental drivers based on the long‐term observation data of ChinaFLUX sites and the published data from other flux sites in China. The results indicate that gross ecosystem productivity (GEP), ecosystem respiration (ER), and net ecosystem productivity (NEP) of terrestrial ecosystems in China showed a significantly latitudinal pattern, declining linearly with the increase of latitude. However, GEP, ER, and NEP did not present a clear longitudinal pattern. The carbon sink functional areas of terrestrial ecosystems in China were mainly located in the subtropical and temperate forests, coastal wetlands in eastern China, the temperate meadow steppe in the northeast China, and the alpine meadow in eastern edge of Qinghai‐Tibetan Plateau. The forest ecosystems had stronger carbon sink than grassland ecosystems. The spatial patterns of GEP and ER in China were mainly determined by mean annual precipitation (MAP) and mean annual temperature (MAT), whereas the spatial variation in NEP was largely explained by MAT. The combined effects of MAT and MAP explained 79%, 62%, and 66% of the spatial variations in GEP, ER, and NEP, respectively. The GEP, ER, and NEP in different ecosystems in China exhibited ‘positive coupling correlation’ in their spatial patterns. Both ER and NEP were significantly correlated with GEP, with 68% of the per‐unit GEP contributed to ER and 29% to NEP. MAT and MAP affected the spatial patterns of ER and NEP mainly by their direct effects on the spatial pattern of GEP.
MicroRNAs (miRNAs) are a class of small single-stranded and highly conserved non-coding RNAs, which are closely linked to cardiac disorders such as myocardial infarction (MI), cardiomyocyte ...hypertrophy, and heart failure. A growing number of studies have demonstrated that miRNAs determine the fate of the heart by regulating cardiac cell death and regeneration after MI. A deep understanding of the pathophysiology of miRNA dependent regulatory pathways in these processes is required. The role of miRNAs as diagnostic, prognostic, and therapeutic targets also needs to be explored in order to utilize them in clinical settings. This review summarizes the role of miRNAs in myocardial infarction and focuses mainly on their influence on cardiomyocyte regeneration and cell death including apoptosis, necrosis, and autophagy. In addition, the targets of pro- and anti-MI miRNAs are comparatively described. In particular, the possibilities of miRNA-based diagnostic and therapeutic strategies for myocardial infarction are discussed in this review.
Heavy metal ions (HMIs) are one of the major environmental pollution problems currently faced. To monitor and control HMIs, rapid and reliable detection is required. Electrochemical analysis is one ...of the promising methods for on‐site detection and monitoring due to high sensitivity, short response time, etc. Recently, nanometal oxides with special surface physicochemical properties have been widely used as electrode modifiers to enhance sensitivity and selectivity for HMIs detection. In this work, recent advances in the electrochemical detection of HMIs using nanometal oxides, which are attributed to specific crystal facets and phases, surficial defects and vacancies, and oxidation state cycle, are comprehensively summarized and discussed in aspects of synthesis, characterization, electroanalysis application, and mechanism. Moreover, the challenges and opportunities for the development and application of nanometal oxides with functional surface physicochemical properties in electrochemical determination of HMIs are presented.
This work systematically summarizes and discusses the synthesis and application of nanometal oxides with special surface physicochemical properties, including crystal facets and crystal phases, defects and oxygen vacancies, and oxidation states cycle in electrochemical detection of heavy metal ions. The sensitive mechanism for enhancing electrochemical signals by these nanometal oxides is highlighted.
Metal hydroxide nanomaterials are widely applied in the energy and environment fields. The electrochemical performance of such materials is strongly dependent on their crystal phases. However, as ...there are always multiple factors relating to the phase‐dependent electrochemistry, it is still difficult to identify the determining one. The well‐defined crystal phases of α‐ and β‐FeOOH nanorods are characterized through the transmission electron microscopy by a series of rotation toward one rod, where the cross‐section shape and the growth direction along the 001 crystalline are first verified for 1D FeOOH nanostructures. The electrosensitivity of the two materials toward Pb(II) is tested, where α‐FeOOH performs an outstanding sensitivity whilst it is only modest for β‐FeOOH. Experiments via Fourier transform infrared spectroscopy, X‐ray absorption fine structure (XAFS), etc., show that α‐FeOOH presents a larger Pb(II) adsorption capacity due to more surficial hydroxyl groups and weaker PbO bond strength. The reaction kinetics are simulated and the adsorption capacity is found to be the determining factor for the distinct Pb(II) sensitivities. Combining experiment with simulation, this work reveals the physical insights of the phase‐dependent electrochemistry for FeOOH and provides guidelines for the functional application of metal hydroxide nanomaterials.
α‐ and β‐FeOOH nanorods with diamond‐ and square‐shaped cross‐sections are synthesized. The phase‐dependent electrosensitivity toward Pb(II) on α‐FeOOH is about 17‐fold higher than β‐FeOOH. Combining kinetic simulation with analyte–material interaction studies, the kinetics in Pb(II) detection are identified, revealing that the phase‐dependent adsorption capacity is the main factor leading to distinct sensitivities on α‐ and β‐FeOOH.
Objective
Bismuth‐containing quadruple therapy for Helicobacter pylori (H. pylori) eradication has a relatively high rate of side effects and high cost, thus the option of a high‐dose dual therapy ...with a high eradication rate and fewer adverse events is a consideration. However, studies of dual therapy are still scarce and are mostly single‐center studies with limited generalizability. Large‐scale, multicenter studies are required. Our study investigated and compared the effectiveness, adverse events, patient compliance, and costs of high‐dose dual therapy with those of bismuth‐containing quadruple therapy in H. pylori‐infected treatment‐naive patients in a prospective, multicenter, open‐label, randomized controlled trial.
Method
Treatment‐naive patients infected with H. pylori were randomly assigned to receive high‐dose dual therapy (esomeprazole 20 mg 4 times daily and amoxicillin 1000 mg 3 times daily, for 14 days) or bismuth‐containing quadruple therapy (esomeprazole 20 mg, amoxicillin 1000 mg, clarithromycin 500 mg, and bismuth potassium citrate 220 mg, all twice daily for 14 days). The effectiveness, adverse events, patient compliance, and costs of both groups were compared.
Results
A total of 700 patients were enrolled. The high‐dose dual therapy group (N = 350) achieved eradication rates of 89.4% (intention‐to‐treat), 90.4% (modified intention‐to‐treat), and 90.6% (per‐protocol), which were similar to rates in the bismuth‐containing quadruple therapy group (N = 350), 84.6%, 88.0%, and 88.2%, respectively (p > 0.05). The high‐dose dual therapy group had a lower rate of adverse events (12.9% vs. 28.1%, p < 0.001) and lower costs (¥590.2 vs. ¥723.22) compared with the quadruple therapy group, respectively. The compliance of both groups was satisfactory (97.7% high‐dose dual vs. 96.8% quadruple, p > 0.05).
Conclusion
High‐dose dual therapy for H. pylori eradication had similar efficacy and compliance, fewer adverse events, and lower costs than bismuth‐containing quadruple therapy for treatment‐naive patients.
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