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In order to facilitate therapeutic drug monitoring of tacrolimus and cyclosporine A in clinical practice, a simple, rapid, robust, sensitive and specific LC–MS/MS assay was developed and validated for the simultaneous determination of tacrolimus and cyclosporine A in human whole blood. Erythrocytes were destroyed using internal standard solution with 10% (w/v) zinc sulfate in water. The analytes were extracted from 100 μl of whole blood by protein precipitation with acetonitrile. Chromatographic separation was conducted on a Kinetex PFP column (60°C) by a gradient elution with a flow rate of 0.450 ml/min in 2.5 min. Quantitative analysis was performed using electrospray ionization and multiple reaction monitoring in positive ionization mode. The method was fully validated as per current guidelines on bioanalytical methodologies of the US Food and Drug Administration and European Medicines Agency. The method developed was applied successfully in analyzing clinical samples from patients administered tacrolimus or cyclosporine A. The sample treatment procedure was rationalized and improved to fulfill the complete target extraction. The chromatography conditions were optimized to achieve rapid and accurate quantification of both analytes. This method may be beneficial as a constructive input for the therapeutic drug monitoring of tacrolimus and cyclosporine A in obtaining individualized therapy. [ABSTRACT FROM AUTHOR]

Soil conservation is of global importance, as accelerated soil erosion by human activity is a primary threat to ecosystem viability. However, the significance and role of soil conservation in reshaping landscape carbon (C) accounting has not been comprehensively integrated in the terrestrial C sink. Here, we present the first integrated assessment of the modified terrestrial C sink and aquatic C transport due to soil conservation for the semiarid Chinese Loess Plateau (CLP), the world's most vulnerable region to soil erosion. We show a surprisingly low terrestrial‐aquatic C transfer that offset the terrestrial net ecosystem productivity by only 7.5%, which we attribute to the effective implementation of soil conservation practices. Despite the highest soil erosion, the semiarid CLP acts as effective C sink at 43.2 ± 22.6 g C m−2 year−1, which is comparable to temperate forest in absorbing atmospheric CO2. Moreover, C burial in reservoirs has created an additional anthropogenic C sink of 2.9 ± 1.1 g C m−2 year−1. Our findings indicate that effective soil conservation can significantly increase landscape C sequestration capacity. The co‐benefits of soil conservation in erosion control and C sequestration have important implications for policy makers in other regions undergoing increasing erosion intensity to pursue environmental sustainability. Plain Language Summary: Aquatic export of terrestrial carbon (C) plays a significant role in modulating the magnitude of terrestrial C sink. Previous estimates of terrestrial C sink may be overestimated because not all C losses across heterogeneous landscapes are accurately determined and properly accounted for. This is particularly possible for catchments with high erosion and terrestrial‐aquatic C transfer potential. Meanwhile, soil conservation can greatly modify landscape C sequestration capacity. Thus, a more comprehensive assessment of net landscape C budget is needed that integrates aquatic export of terrestrial C while considering the role and significance of soil conservation. For the Chinese Loess Plateau in semiarid climates that once characterized the world's high soil erosion rate, we show a surprisingly low aquatic C transfer that offset the terrestrial C sink by only 7.5%, due largely to successful soil conservation in the past decades. Our findings suggest that effective implementation of soil conservation practices can substantially reduce terrestrial‐aquatic C transfer and enhance the landscape C sequestration capacity. Key Points: The magnitude of terrestrial‐aquatic C transfer in influencing landscape‐scale C balance on the Chinese Loess Plateau (CLP) is assessedThe low reduction of terrestrial C sink by terrestrial‐aquatic C transfer on the CLP is largely due to soil conservationEffective implementation of soil conservation can substantially reduce terrestrial‐aquatic C transfer and enhance landscape C sink capacity [ABSTRACT FROM AUTHOR]

Sediment fingerprints have been widely used in source identification studies. Optical features have become a powerful substitute for traditional fingerprints in recent years due to their fast measurement and low analysis costs. However, the accuracy of optical fingerprinting methods has received little attention. Here, artificial mixing and indoor scouring experiments were carried out to compare and assess the accuracy of optical fingerprinting results using three spectroscopic ranges [visible (VIS), near‐infrared (NIR), and mid‐infrared (MIR) spectroscopy] in multivariate models and using 19 colour parameters [such as red (R), green (G) and blue (B) in an RGB system; virtual component X (X), brightness (Y) and virtual component Z (Z) in a CIE XYZ system and so on] coupled with the conventional method. Furthermore, we examined how sediment sorting (particle sorting and organic matter enrichment) affects the accuracy of source apportionments. The results showed that VIS, NIR and MIR spectroscopic tracers presented high accuracy in scouring and artificial mixtures, with mean absolute error (MAE) values of 4.98% and 5.91%. In contrast, the colour parameters had weak performances in two experiments (MAE = 16.83% and 15.05%). Additionally, similar fingerprinting results of the scouring mixtures (MAE = 7.95%) and artificial mixtures (MAE = 8.20%) indicated that slight particle sorting and organic matter enrichment have little effect on the accuracy of optical fingerprinting results. Our study shows that sediment fingerprinting based on optical features, especially three spectroscopic ranges, has good applicability in sediment source identification. [ABSTRACT FROM AUTHOR]

Sediment source fingerprinting provides an effective and reliable way for targeted control of soil erosion. However, the accuracy of source contribution predictions of different fingerprinting methods has not been well verified, which affects the further application of these methods. Here, compared with the real sediment sources measured by indoor simulated scouring experiments, we verified the accuracy of two tracers (geochemical elements and n‐alkanes) and three mixing models (Walling model, MixSIAR, and Landwehr model). The results showed that geochemical properties have high accuracy in identifying sediment sources, with the mean absolute error (MAE) ranging from 3.5%–5.9%, while poor results were shown for n‐alkanes (MAE values 7.5%–45.7%). The Walling model and MixSIAR showed higher accuracy of contribution prediction, and the MAE was 3.5%–5.9% and 0.7%–3.5%, respectively. Although Landwehr also presented high accuracy of model output, it was relatively less robust compared with the former two mixing models (the MAE range was 3.8%–9.7%). Furthermore, the mixing model with three correction factors (particle size, organic matter (OM), and particle size with OM) showed poor output results for scouring experiments. This study provides a reference for the selection and determination of tracers, mixing models, and correction factors in field experiments. [ABSTRACT FROM AUTHOR]

China's Grain‐for‐Green Program (GFGP) motivates conversion from steep slope cropland to forest or grassland to reverse serious land degradation. However, impoverished farmers potentially persist with inefficient slope farming for survival, thereby threatening the sustainable GFGP efforts. Consequently, a strategy for balancing farming and vegetation restoration from a spatial optimization perspective is necessary. Here, we selected two catchments with high and low agricultural intensity in the loess hilly and gully regions for a case study. Spatial analysis and binary logistic regression models were used to clarify the effects of topography, accessibility, and location factors on cropland distribution and explore spatially optimized cropland distribution. The results show that steep slope cropland is still widespread, of which cropland with slopes >15° accounts for 46.7% and 34.7% in the two catchments, respectively. Residences and roads significantly impact steep slope cropland distribution, and around 80% of cropland with slopes >15° is distributed within 200 m from residences or 100 m from roads. In cropland redistribution scenarios, cropland with slopes >25° and >15° can be redistributed to gentler slopes while maintaining cropland areas in catchments with high and low agricultural intensity. Correspondingly, 38.8% and 81.2%, respectively, of simulated cropland on gentle slopes needs optimized attributes such as accessibility in order to be priorities of farmers. Our research provides new insights into GFGP strategies for steep slope cropland restoration in catchments with different agricultural intensities, thereby advancing sustainable farming and vegetation restoration in China's mountainous regions. [ABSTRACT FROM AUTHOR]

Atmospheric CO2 fixation by autotrophic microbes has been investigated in various habitats, but little is known about the microbial CO2 fixation capacity in soil degraded by erosion. To fill the knowledge gap about the role of autotrophic microbes in organic matter accumulation in degraded soil, the microbial CO2 fixation rate was estimated in nondegraded, lightly degraded, and severely degraded soils using 13C stable isotope tracing technique. The influences of soil physical properties, nutrient contents, and autotrophic bacterial community on the microbial CO2 fixation capacity were investigated using a structural equation model. The results showed that soil degradation significantly reduced the autotrophic bacterial abundance. However, a higher species diversity and a more complex cooccurrence network of autotrophic bacterial taxa were observed in the lightly degraded soil than in the nondegraded and severely degraded soils. Interestingly, the microbial CO2 fixation rates in the lightly and severely degraded soils were 2.15‐ and 1.52‐times higher than those in the nondegraded soil, respectively. The annual organic carbon fixed by autotrophic microbes exceeded 2.05% of the total organic carbon in the degraded soil, suggesting that autotrophic microbes play a vital role in organic matter accumulation in degraded soil. The structural equation model showed that soil nutrients other than the autotrophic bacterial community are the key factor affecting the microbial CO2 fixation capacity. The negative effect of soil nutrients on the CO2 fixation capacity indicates that autotrophic microbes exert a more important function at the initial stage of the restoration of degraded soil. [ABSTRACT FROM AUTHOR]

China has implemented the world's largest‐ever vegetation restoration program in marginal mountainous areas to sustain life on land. However, land competition between the demand for grain and the need for green has threatened sustainable vegetation restoration. Here, focusing on China's marginal mountainous areas with the highest density of slope cropland, we explore the optimal solution in the trade‐offs between green and grain. We find that current vegetation restoration strategies are not sufficiently optimized, which may threaten the survival and development of local farmers and in turn destroy existing vegetation restoration achievements. Through adjusting vegetation restoration objectives carefully tailored to local conditions, the population experiencing grain shortages can be greatly reduced by 51–66% (from 18.26 million to 6.29–8.90 million) compared with the current scheme. The optimal design will alleviate the conflict between grain and green, thereby promoting sustainable ecological restoration in China. Our research provides an important reference for the world's mountainous areas to achieve a win‐win situation between green and grain. Plain Language Summary: Vegetation restoration in China has made remarkable achievements in recent years. However, the sustainability of these vegetation restoration programs has been questioned and challenged. Combined with spatial statistics and scenario analysis for analyzing the trade‐offs between green and grain, we find that the current vegetation restoration strategies in China's mountainous areas are not sufficiently optimized, which may affect the sustainability of vegetation restoration programs. Vegetation restoration strategies adapted to local conditions can reduce the risk of grain shortage for 9.30–11.97 million farmers, and contribute to a more balanced development and the sustainability of vegetation restoration in mountainous areas. Key Points: Chinese farmers rely heavily on slope cropland and self‐sufficient farming in marginal mountainous areasCurrent vegetation restoration strategies are not sufficiently optimized, which may affect farmers' livelihood in mountainous areasPlanning tailored to local conditions can alleviate the conflict between grain and green, and promote sustainable vegetation restoration [ABSTRACT FROM AUTHOR]

Cases of coronavirus disease 2019 (COVID‐19) emigrating from Wuhan escalated the risk of spreading the disease in other cities. This report focused on outside‐Wuhan patients to assess the transmission and clinical characteristics of this illness. Contact investigation was conducted on each patient who was admitted to the assigned hospitals in Hunan Province (geographically adjacent to Wuhan) from 22 January to 23 February 2020. Cases were confirmed by the polymerase chain reaction test. Demographic, clinical, and outcomes were collected and analyzed. Of the 104 patients, 48 (46.15%) were cases who immigrated from Wuhan; 93 (89.42%) had a definite contact history with infection. Family clusters were the major body of patients. Transmission along the chain of three "generations" was observed. Five asymptomatic infected cases were found and two of them infected their relatives. Mean age was 43 (range, 8‐84) years, and 49 (47.12%) were male. The median incubation period was 6 (range, 1‐32) days, which of 8 patients ranged from 18 to 32 days, 96 (92.31%) were discharged, and 1 (0.96%) died. The average hospital stay was 10 (range, 8‐14) days. Family but not community transmission became the main body of infections in the two centers, suggesting the timely control measures after the Wuhan shutdown worked well. Asymptomatic transmission demonstrated here warned us that it may lead to the widespread of COVID‐19. A 14‐day quarantine may need to be prolonged. Highlights: The smoothly increase in the cumulative number of confirmations of the two centers indicates that the timely control measures work well, family clusters represent as the major body of infections, transmission along the chain of 3 "generations" was observed. No gender difference of patients was found, indicating male and female may have the same susceptibility of this illness. But the asymptomatic transmission demonstrated here warned us it may bring more risk to the spread of COVID‐19. The differences in demographics and clinical characteristics between emigrated patients and indigenous cases were not significant. [ABSTRACT FROM AUTHOR]

Plant community characteristics and functional traits may respond to soil erosion due to their high plasticity in varied environments. However, the linkages between plant functional traits and soil properties under erosion stress remain poorly understood, despite the fundamental role they play in controlling soil erosion. Here, we selected 50 plots on degraded land caused by long‐term water erosion representing three degrees of erosion that differed in terms of soil profile and erosion landform. We measured aboveground plant characteristics, root functional traits, and soil properties to explore their responses to the degree of erosion and to identify the main factors mitigating soil erodibility (Kr). The results showed that vegetation cover and root length density (RLD) were the plant variables that were most sensitive to the erosion stress. Topographic parameters strongly affected plant community characteristics (vegetation cover and litter mass) by favouring thicker soil layers and lower bulk densities, and soil texture strongly affected root functional traits (root mass density [RD] and RLD) by favoring lighter soils. Importantly, plant community characteristics and root functional traits were the main drivers of Kr mitigation through their mediation effects on a range of soil properties (e.g., soil organic matter, aggregate stability, and shear strength) during the restoration, and vegetation can still be efficient in maintaining and restoring soil functions, even on severely degraded land. Overall, these findings could guide restoration practices to meet soil conservation and ecosystem function goals in degraded ecosystems. [ABSTRACT FROM AUTHOR]

Soil erosion modulates the atmospheric CO2 level by affecting the redistribution of young biospheric organic carbon (OCbio) and ancient petrogenic organic carbon (OCpetro) in different order streams. However, the fate of soil organic carbon (SOC) in low‐order stream systems is still uncertain due to the complex influences of terrain, land uses, and anthropogenic disturbances. Here, we used the geochemical properties fingerprinting method and a radiocarbon‐based two‐member mixing model to clarify the source, budgets, and composition of SOC in a low‐order stream catchment in the Yellow River basin. The results showed that the primary source of SOC in the catchment was agricultural activity area, which accounted for 68.5%. After vegetation restoration, the SOC delivery rate and loss rate decreased from 0.38 ± 0.06 to 0.26 ± 0.04 and 0.19 ± 0.06 to 0.14 ± 0.04 t·ha−1·yr−1, respectively. The SOC mobilized by soil erosion in the source area was 1,085.8 ± 170.5 t from 1969 to 2015, and the SOC lost during the transport process was 552.9 ± 170.1 t. The lost carbon was dominated by OCbio, whereas the loss of OCpetro was minimal. Soil erosion can mobilize the OCpetro sequestered in terrestrial ecosystems and deliver it to a river system if it is not intercepted. The oxidation of OCpetro during long‐distance fluvial transport may represent a significant carbon source for atmospheric CO2 on a geological timescale. This study contributes to our understanding of the carbon sink/source issue and quantifies the SOC budgets in stream systems. Plain Language Summary: Understanding how soil erosion affects the redistribution and delivery of soil organic carbon (SOC) is essential for clarifying the source, budgets, and composition of SOC and helps us further understand the terrestrial carbon cycle. This study calculated the source of SOC based on differences in geochemical properties in different source areas. Then, we measured the radiocarbon (14C) content to clarify the composition and fate of SOC during the erosion process. We found that the primary source of SOC in the catchment was the agricultural activity area and that agricultural activities and vegetation restoration were shown to significantly affect SOC redistribution. A large amount of modern organic carbon was lost during the transport process and may become an atmospheric CO2 source over short timescales. Almost all ancient organic carbon is intercepted by the dam at the outlet. If there is no check dam, the remaining ancient organic carbon can be exported to the Yellow River and then oxidized during fluvial transport, leading to an increase in long‐term atmospheric CO2 levels. This research clarifies the influence of soil erosion on SOC redistribution and delivery and quantifies the source, budget, and composition of SOC in the low‐order stream system. Key Points: Agricultural activities and vegetation restoration have impacted the sediment and erosion‐induced redistribution of soil organic carbonA large amount of soil organic carbon was lost during the transport process, and the lost carbon was dominated by biospheric organic carbonThe petrogenic organic carbon exported from the low‐order stream may become a carbon source on a geological timescale [ABSTRACT FROM AUTHOR]

As an important soil and water conversation endeavor, the 'Grain for Green' project launched by the Chinese Central Government almost doubled the vegetation cover on the Loess Plateau between 1999 and 2013. The corresponding vegetation restoration considerably diminished slope erosion throughout the Loess Plateau, although erosion in gullies remains poorly understood. In this paper, a composite fingerprinting approach was employed to assess the relative importance of the erosion of gully and slope soils within a typical dam‐controlled catchment of the Loess Plateau. A total of 23 couplets were identified based on the deposited layer thicknesses and extreme rainfall event records along the sediment profile. The results suggest that gullies contributed 71% to the overall sediment proportion, and those sediments had an increased tendency to accumulate during 2010–2016 under the 'Grain for Green' project. The sediment inputs from slope areas were predicted to be 29%. The eroded gullies materials mainly consisted of silt‐sized particles, which dominated the eroded sediment. Silt particles with sizes of 0.02–0.05 mm constituted the main particles in both deposit sediments and gully materials, whereas the slope areas mainly contained particle sizes of <0.01 mm. The check dam proved to be effective at trapping coarse silt with 27–42% of the total sediment content. This study presents reliable information on the importance of gullies as sediment source materials and verifies the applicability of tracing procedures for collecting information on sediment effluxes from both slopes and gullies. [ABSTRACT FROM AUTHOR]

The doped organic/organic p-n heterojunctions have been applied as charge generation structure (CGS) in tandem organic light emitting diodes (TOLEDs). It is found that the field-induced charge generation takes place more efficiently at the interface between Li2CO3 n-doped bathocuproine (BCP:Li2CO3) and MoO3 p-doped 4,4′- N, N′-dicarbazole-biphenyl (CBP:MoO3) than at the interface between BCP:Li2CO3 and MoO3 p-doped 4,4-bis[ N-1-naphthyl- N-phenylamino]biphenyl (NPB:MoO3). It is because the process of electrons tunneling through the depletion zone from the highest occupied molecular orbit (HOMO) of CBP:MoO3 to the lowest unoccupied molecular orbit (LUMO) of BCP:Li2CO3 is more efficient than that from the HOMO of NPB:MoO3 to the LUMO of BCP:Li2CO3. Compared to the TOLED using the conventional CGS of 10-nm BCP:Li2CO3/20-nm NPB:MoO3, the one using the CGS of 10-nm BCP:Li2CO3/10-nm CBP:MoO3/10-nm NPB:MoO3 shows increased device performance. In addition, the interconnecting property of CGS of 10-nm BCP:Li2CO3/ x nm CBP:MoO3/20 − x nm NPB:MoO3 shows a strong dependence on the thickness of CBP:MoO3. We provide a new insight on optimizing Ohmic loss in the CGSs, useful for improving the performance of TOLEDs. [ABSTRACT FROM AUTHOR]