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A diabetic wound causes thousands of infections or deaths around the world each year, and its healing remains a critical challenge because of the ease of multidrug-resistant (MDR) bacterial infection, as well as the intrinsic hyperglycemic and hypoxia microenvironment that inhibits the therapeutic efficiency. Herein, we pioneer the design of a photobiocatalytic cascade nanoreactor via spatially organizing the biocatalysts and photocatalysts utilizing a hydrogen-bonded organic framework (HOF) scaffold for diabetic wound therapy. The HOF scaffold enables it to disperse and stabilize the host cargos, and the formed long-range-ordered mesochannels also facilitate the mass transfer that enhances the cascade activity. This integrated HOF nanoreactor allows the continuous conversion of overexpressed glucose and H

Nanozymes are of particular interest due to their enzyme-mimicking activity and high stability that are favorable in biomedical sensing and immunoassays. In this work, we report a highly specific N-doped nanozyme through pyrolysis of framework-confined bovine serum albumin (BSA). This strategy allows one to translate the low-cost and featureless BSA into a highly active enzyme mimic. The obtained carbon nanozyme (denoted as HBF-1-C800) displays 3- to 7-fold enhancement on peroxidase (POD) activity compared with the conventional carbon nanozymes and also shows ca. 5-fold activity enhancement compared to the reported N-doping graphene. Such excellent POD activity originates from high N-doping efficiency, protein-induced defective sites, and the intrinsic porous structure of HBF-1-C800, which provides abundantly accessible active sites and accelerates substrate diffusion simultaneously. Importantly, the HBF-1-C800 nanozyme has highly specific POD activity and also enables resistance to several harsh conditions that should denature natural enzymes. These features allow it with high accuracy, stability, and sensitivity for biosensing applications. Moreover, HBF-1-C800 has been designed as a promising platform for colorimetric biosensing of several biomarkers including H2O2, glutathione, and glucose, with wide linear ranges and low limits of detection that are satisfied with the disease diagnosis.

Improving our understanding of the impacts of climate variation and human activities on grassland dynamics is heightened by expectations that climate variation and human activities may induce grassland degradation. An accurate evaluation of the respective impacts of climate variation and human activities on grassland dynamics is crucial to understand the grassland degradation mechanism and to control the degraded grassland. In this study, net primary productivity (NPP) was selected as an indicator to reflect grassland dynamics. Meanwhile, the potential NPP (PNPP) and human-induced NPP (HNPP) calculated as the difference of PNPP and actual ANPP (ANPP) were used to assess the relative effects of climate variation and human activities on grassland NPP changes in China during 2000–2013. Results of grassland ANPP showed an overall increase than decrease in productivity (81.21% vs 18.79%) from 2000 to 2013. For the increase of ANPP, the relative contribution of climate variation and human activities to grassland NPP changes were 41.45% and 45.22%, respectively. Climate variation was the dominant factor that induced the increase in ANPP mainly in areas of Sichuan, Gansu, Ningxia and Inner Mongolia. An increase in Human-dominated ANPP mainly occurred in Tibet, Qinghai and Xinjiang. The decrease in ANPP is principally controlled by the effect of human activities than that of climate variation, especially in Inner Mongolia. Meanwhile, climate-dominated ANPP increase and human-dominated ANPP decrease mainly occurred in plain grassland, desert grassland and meadow across the six types of grasslands in China. Furthermore, in alpine sub-alpine meadow and alpine sub-alpine, while climate-dominated ANPP of grassland was found to be decreased, an increase in human-dominated ANPP was detected. The increase in precipitation and the implementation of ecological restoration programs were found to be effective in inducing the noticeable increased grassland ANPP since 2003. The findings of the current research recommend that the Chinese government should continue to implement the prohibiting graze policy across the country and extensively strengthen the implementation of the policy in Inner Mongolia and North Xinjiang, particularly in plain grassland, desert grassland and meadow.

Crystallization of biomacromolecules-metal-organic frameworks (BMOFs) allows for orderly assemble of symbiotic hybrids with desirable biological and chemical functions in one voxel. The structure-activity relationship of this symbiotic crystal, however, is still blurred. Here, we directly identify the atomic-level structure of BMOFs, using the integrated differential phase contrast-scanning transmission electron microscopy, cryo-electron microscopy and x-ray absorption fine structure techniques. We discover an obvious difference in the nanoarchitecture of BMOFs under different crystallization pathways that was previously not seen. In addition, we find the nanoarchitecture significantly affects the bioactivity of the BMOFs. This work gives an important insight into the structure-activity relationship of BMOFs synthesized in different scenarios, and may act as a guide to engineer next-generation materials with excellent biological and chemical functions.

Understanding the net primary productivity (NPP) of grassland is crucial to evaluate the terrestrial carbon cycle. In this study, we investigated the spatial distribution and the area of global grassland across the globe. Then, we used the Carnegie-Ames-Stanford Approach (CASA) model to estimate global grassland NPP and explore the spatio-temporal variations of grassland NPP in response to climate change from 1982 to 2008. Results showed that the largest area of grassland distribution during the study period was in Asia (1737.23 × 104 km2), while the grassland area in Europe was relatively small (202.83 × 104 km2). Temporally, the total NPP increased with fluctuations from 1982 to 2008, with an annual increase rate of 0.03 Pg C/yr. The total NPP experienced a significant increasing trend from 1982 to 1995, while a decreasing trend was observed from 1996 to 2008. Spatially, the grassland NPP in South America and Africa were higher than the other regions, largely as a result of these regions are under warm and wet climatic conditions. The highest mean NPP was recorded for savannas (560.10 g C/(m2·yr)), whereas the lowest was observed in open shrublands with an average NPP of 162.53 g C/(m2·yr). The relationship between grassland NPP and annual mean temperature and annual precipitation (AMT, AP, respectively) varies with changes in AP, which indicates that, grassland NPP is more sensitive to precipitation than temperature.

Natural disaster vulnerability can intuitively reflect the susceptibility of an area to environmental changes. Better understanding the spatial distribution of natural disaster vulnerability is a critical process for taking effective adaptation and management. Although significant achievements have been made in disaster vulnerability, few studies are known about natural disaster vulnerability at the national scale, especially from the typical natural disaster events in China. In this study, with normalizing selected indicators and calculating vulnerability index, we analyzed the spatial distribution of natural disasters vulnerability during 2010–2017 using the geospatial techniques. The results showed that natural disaster vulnerability has certain spatial differences, but different natural disaster can occur in the same area during the study period. Drought disaster can occur in all regions of China, especially in Inner Mongolia. Flood disaster is mainly concentrated in the middle and lower reaches of the Yangtze River and the Yellow River Basin. The wind and storm disaster is chiefly in the northern regions in China. The freezing disaster is widely distributed in China. Furthermore, the regions with low vulnerability were primarily distributed in the eastern coastal region, indicating that the rapid development of economy and technology can resist or mitigate natural disaster to a certain extent. This study offers a solution to study natural disasters and provides scientific basis for disaster prevention and mitigation actions.

Embedding an enzyme within a MOF as exoskeleton (enzyme@MOF) offers new opportunities to improve the inherent fragile nature of the enzyme, but also to impart novel biofunctionality to the MOF. Despite the remarkable stability achieved for MOF-embedded enzymes, embedding patterns and conversion of the enzymatic biofunctionality after entrapment by a MOF have only received limited attention. Herein, we reveal how embedding patterns affect the bioactivity of an enzyme encapsulated in ZIF-8. The enzyme@MOF can maintain high activity when the encapsulation process is driven by rapid enzyme-triggered nucleation of ZIF-8. When the encapsulation is driven by slow coprecipitation and the enzymes are not involved in the nucleation of ZIF-8, enzyme@MOF tends to be inactive owing to unfolding and competing coordination caused by the ligand, 2-methyl imidazole. These two embedding patterns can easily be controlled by chemical modification of the amino acids of the enzymes, modulating their biofunctionality.

Drought disaster space agglomeration assessment is one of the important components of meteorological disaster prevention and mitigation. Agriculture affected by drought disaster is not only a serious threat to world food security, but also an obstacle to sustainable development. Additionally, China is an important agricultural import and export country in the world. Therefore, we used the global Moran’s I and the local indicators of spatial autocorrelation (LISA) to reveal the spatial agglomeration of agricultural drought disaster in China from1978 to 2016, respectively. The results showed that China’s agricultural drought disaster presents local spatial autocorrelation of geographical agglomeration at national level during the study period. The spatial agglomeration regions of China’s agricultural drought disaster were in Inner Mongolia, Jilin province, Heilongjiang province, Liaoning province, Shanxi province, Hebei province, Shandong province, Shaanxi province and Henan province, indicating that agricultural drought disaster mainly distributed in North and Northwest China, especially occurred in the Yellow River Basin and its north areas. We also found that the overall movement direction of agricultural drought disaster agglomeration regions was northwest, and the maximum moving distance was 722.16 km. Our results might provide insight in early warning and prevention for drought disaster.

Quantitatively assessing the impacts of drought on grassland has significant implications to understand the degradation mechanism and prevention degraded grassland. In this study, we analyzed the relationship between grassland drought and grassland Net Primary Productivity (NPP) based on the self-calibrated Palmer Drought Severity Index (scPDSI) from 1982 to 2008. The results showed that the global grassland scPDSI value had a slightly increasing trend with the rate of 0.0119 per year (R2 = 0.195), indicating that the global grassland drought lighter to some extent during study period. Moreover, the correlation coefficient between annual grassland NPP and scPDSI was from −0.83 to 0.92. The grassland NPP decreased under mild drought from 1992 to 1996. Additionally, the correlation coefficient between scPDSI and NPP for each grassland type was: Closed Shrublands > Non-woody grassland > Savannas > Open Shrublands > Woody Savannas, indicating that drought had difference influences on the different grassland types. Our results might provide the underlying insights needed to be guide for the effects of extreme weather events on grassland NPP.

Covalent organic frameworks (COFs) are crystalline porous organic polymers constructed with molecular building units via diverse linkage chemistries. Recently, COF materials have shown great potential in sample preparation science due to their tunable properties, large surface area, and unique structural robustness. Here, a comprehensive overview is provided, consisting of a brief introduction on synthetic strategies of COFs for sample preparation and the progress in the application of COF materials as promising sorbents. Then, recent advancements of COFs in biological analysis including peptidomics and proteomics analysis, nucleic acids and endogenous substances analysis, enantiomers and pharmaceutical analysis are summarized and highlighted. Finally, the current challenges and future trends of COFs with respect to their preparation and applications in biological field are tentatively discussed.

Portable devices featured with fast analysis and affordable methodologies for clinical diagnostics have stimulated the rapid development of point-of-care (POC) technologies, potentially lowering the mortality rate. Herein, we demonstrated a portable, robust, and user-friendly intelligent metal-organic frameworks (MOFs) paper device, called smartphone-assisted biomimetic MOFs nanoreactor colorimetric paper (SBMCP), for on-demand POC detection of endogenous biomolecules. The concept of this paper platform was analogous to the intracellular cascades signal transduction, wherein the single/multiple enzymes components trapped within a ZIF-8 exoskeleton allowed the sensitive and selective recognition of target analyte via the accessible micropores network of ZIF-8, and then transferred the recognition event to a visual color signal based on the cascade reaction. Meanwhile, the ZIF-8 exoskeleton also endowed the enzymes with significantly elevated stability. As a result, this robust and portable SBMCP sensor enabled the on-site analysis of different important disease-related biomolecules through modulating the enzyme cascades, combining with a custom-designed smartphone application for signal readout. In the SBMCP assay, no sophisticated instruments or professional skill of the user was required, only 5 μL sample volume was needed, and the whole analysis process could be achieved within a portable MOFs paper and pervasive smartphone, endowing this new assay with the merits of low-cost, time-saving and easy-to-use. We demonstrated this SBMCP sensor was capable of real-time colorimetric detection of glucose and uric acid in diabetes and gout events. It is believed that this portable biosensor platform proposed herein potentially represents promising alternatives for POC diagnosis, especially applicable in developing world and resource-limited settings.

An agricultural drought disaster was analyzed with the new insight of rescaled statistics (R/S) and wavelet analysis in this study. The results showed that: (1) the Hurst index of the agricultural disaster area, the inundated area of agricultural drought disaster, and the grain loss was 0.821, 0.874, and 0.953, respectively, indicating that the process of the agricultural drought disaster had stronger positive continuity during the study period, (2) based on the Morlet analysis of the agricultural disaster area, the inundated area of the agricultural drought disaster, and the grain loss of China from 1950 to 2016, the time series of the agricultural drought had multiple time scale features with the periodic variation on a large scale containing the periodic variation on a small scale, and (3) in the last 67 years, the strong wavelet energy spectrum of the agricultural disaster area, the inundated area of the agricultural drought disaster, and the grain loss was at the time scale of &asymp, 22&ndash, 32 years, &asymp, 24&ndash, 32 years, and &asymp, 25&ndash, 32 years, respectively. In addition, the first major period in the agricultural drought disaster area, the inundated area of agricultural drought disaster, and the grain loss had average periods of approximately 16 years, 16 years, and 18 years, respectively.

While quantitative assessment of ecosystems degradation is quite addressed in the literature, quantitatively separating the relative contribution of climate variation and human activities to grassland ecosystem degradation is still limited, although well recognized as a key knowledge for a better understanding of the degradation mechanisms and for more efficient control of degradation processes. In this study, actual net primary productivity (ANPP) was selected as an indicator to investigate the grassland dynamics from 2000 to 2013. In addition, potential NPP (PNPP) and human-induced NPP (HNPP), which was calculated as the difference between PNPP and ANPP, were used to differentiate the relative impacts of climate variation and human activities on grassland degradation/restoration, respectively. Results showed that 60.94% of the total global area of grassland experienced restoration over the study period, with an increase in NPP by 1864.81 Tg C across the globe. The restored areas induced by climate variation and human activities accounted for 45.73% and 34.99% with an increases in NPP by 852.75 Tg C and 652.50 Tg C, respectively. By contrast, nearly 39.06% of the global grassland area experienced degradation. This degradation was associated with a noticeable decrease in ANPP by 325.53 Tg C. While 45.45% of the degraded grassland areas were influenced by climate variation, human activities were accounted for around 40.11% of this degradation. The relative effect of the two factors (i.e. climate variation and human activities) on grassland changes was found to vary greatly among the studied six continents. While human activities exerted larger impacts than climate variation on grassland degradation in North America and Europe, climate variation was the dominant factor for grassland restoration in Asia, Europe, Oceania and North America, which can be mainly attributed to the increase in precipitation during the study period. The findings of the current study improved our understanding of the relative impacts of climate variation and human activities on grassland degradation and restoration at the global scale.

Peaches (Prunus persica) are known for their palatable favor and abundant nutrients. However, peaches tend to rapidly decay during the harvest period in summer. To preserve the postharvest quality and extend the shelf life, an edible coating composed by 1.0% sodium alginate (SA) with and without rhubarb (Rheum rhaponticum L.) extract was applied to peach fruits. Variations in weight loss, firmness, soluble solids content (SSC), respiration rate, maleic dialdehyde (MDA) content, polyphenol oxidase (PPO) activity and sensory attributes were evaluated at room temperature (28 ± 1 °C). The effectiveness of rhubarb-SA coating to control postharvest decay of peach fruits was also investigated. The results showed that the weight loss, respiration rate, MDA content, and PPO activity were much lower, whereas the firmness and the SSC were much higher in the rhubarb-SA coated samples than in the 1.0% SA coated samples and control group. At the end of storage, peach fruits treated with rhubarb-SA coating maintained good sensory quality. Furthermore, the rhubarb-SA coating treatment had quite a beneficial effect on the decay inhibition caused by Penicillium expansum. Our study proves that the alginate coating entrapped with rhubarb extract has the potential to improve postharvest quality and prolong the shelf life of peach fruits.

Grassland plays a key role in socioeconomic development and environmental protection in Africa. Climate variation and human activities are two main drivers of grassland dynamics. Quantitatively assessing the contributions of these two factors and understanding the driving mechanisms are important in ecosystem adaptation and management. In this research, the spatiotemporal patterns of grassland dynamics in Africa during 2000–2015 were analyzed based on the net primary productivity (NPP), M-K test, linear regression analysis, and correlation analysis. In addition, the potential NPP (PNPP), human-induced NPP (HNPP) and actual NPP (ANPP) were employed to establish scenarios to distinguish the relative impacts of climatic and human factors on grassland dynamics. An overall grassland ANPP increase than decrease (62.91% vs 37.09%) was found during 2000–2015. 21.80% of the total grassland area showed increases in ANPP, which was influenced by climate variation, whereas 23.61% were affected by human activities. The ANPP decreases induced by climate variation, human activities and the combination of these two factors occupied 19.31%, 8.39% and 9.39% of the total grassland area, respectively. Therefore, the contributions of climatic and human factors on ANPP increase were almost consistent, while climate variation was the dominated factor on ANPP decrease. In addition, the respective roles of these two factors were quite different in five grassland types. The dynamics of ANPP in closed shrublands, non-woody grasslands, and open shrublands were mainly attributed to the climate variation. Meanwhile, the human-dominated increases in ANPP were observed in woody savannas. Further analysis demonstrated that the increases in African grassland ANPP are likely due to the mitigation of drought and reduction in land use intensity, while the decreases in ANPP were related to unbalance of local hydrothermal condition and overgrazing. This study expects to improve the understanding of the respective contributions of climatic and human factors on grassland dynamics in Africa.