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A protocol for the preparation of 7-amido indoles via regioselective C-H bond functionalization has been first accomplished under Ru(II) catalysis. Indole derivatives and 4-aryl/heteroaryl/benzyl/alkyl dioxzaolines containing various substituents were applicable for this transformation, readily providing the amidated indoles in moderate to good yields. This novel process has many advantages, including good compatibility with diverse functional groups, broad substrate scopes, and mild reaction conditions. Deuteration studies and control experiments have been performed to understand the mechanism of this transformation.

To extract the time-series characteristics of the original bearing signals and predict the remaining useful life (RUL) more effectively, a parallel multichannel recurrent convolutional neural network (PMCRCNN) is proposed for the prediction of RUL. Firstly, the time domain, frequency domain, and time-frequency domain features are extracted from the original signal. Then, the PMCRCNN model is constructed. The front of the model is the parallel multichannel convolution unit to learn and integrate the global and local features from the time-series data. The back of the model is the recurrent convolution layer to model the temporal dependence relationship under different degradation features. Normalized life values are used as labels to train the prediction model. Finally, the RUL was predicted by the trained neural network. The proposed method is verified by full life tests of bearing. The comparison with the existing prognostics approaches of convolutional neural network (CNN) and the recurrent convolutional neural network (RCNN) models proves that the proposed method (PMCRCNN) is effective and superior in improving the accuracy of RUL prediction.

Plants use both cell surface and intracellular immune receptors with leucine rich-repeat (LRRs) to detect pathogens. LRR receptor kinases (LRR-RKs) and LRR receptor-like proteins (LRR-RPs) recognize extracellular microbe-derived molecules to confer pattern-triggered immunity (PTI), while nucleotide-binding LRR (NLR) proteins detect microbial effectors inside the cell to confer effector-triggered immunity (ETI). Despite PTI and ETI signaling being initiated in different compartments, both rely on the transcriptional activation of similar sets of genes, suggesting convergence in signaling upstream of nuclear events. Here we report that two sets of molecules, helper NLRs from the ADR1 (ACTIVATED DISEASE RESISTANCE 1) family as well as lipase-like proteins EDS1 (ENHANCED DISEASE SUSCEPTIBILITY 1) and PAD4 (PHYTOALEXIN DEFICIENT 4), are required not only for ETI, but also for PTI. A further similarity is seen in the evolutionary patterns of some PTI and ETI receptor genes, with both often being highly polymorphic, and with nevertheless distinct roles of LRR-RK and LRR-RP receptors in immunity. We find that the LRR-RK SOBIR1 directly links LRR-RPs with the ADR1 helper NLR as well as EDS1 and PAD4, suggesting the formation of constitutive supramolecular signalosome complexes at the inner side of the plasma membrane. We propose that the EDS1-PAD4-ADR1 node is an essential component and convergence point for immune signaling cascades activated by both surface-resident LRR-RP receptors and intracellular NLR receptors.

To explore the clinical application value of color Doppler ultrasound combined with computed tomography (CT) in the diagnosis of axillary lymph node metastasis (ALNM) in breast cancer.From January 2016 to June 2018, 189 breast cancer patients who underwent radical mastectomy in our hospital were included and retrospectively analyzed. All patients had preoperative color Doppler ultrasound and CT examination of mammary gland and axillary lymph nodes, with pathological diagnosis as the gold standard. Eighty-eight cases were divided into axillary lymph node metastasis group (metastatic group) and 101 cases formed the non-axillary lymph node metastasis group (non-metastatic group). The ultrasound and CT imaging of axillary lymph nodes were analyzed to evaluate the value of color Doppler ultrasound combined with CT in the assessment of axillary lymph node metastasis in breast cancer.Ultrasonographic metastatic lymph nodes showed unclear borders and eccentric thickening of the cortex. The enhancement scan showed obvious heterogeneous enhancement and disappearance of lymphatic structure. The sensitivity, accuracy, and negative predictive value of ultrasonography combined with CT were 92.05%, 90.48% and 92.78%, retrospectively, which were significantly improved compared with those in the individual tests (x2=13.41, 6.126, 8.933, p=0.001, 0.047, 0.011), with significant statistical difference.Color Doppler ultrasound combined with CT examination can significantly improve the detected rate of axillary lymph node metastasis in breast cancer before surgery, and provide a reliable basis for the treatment options on breast cancer patients before surgery.

An efficient route for the coupling of maleimides with chromones at the C5-position has been developed under Ru(II) catalysis. It could provide 1,4-addition products and oxidative Heck-type products by switching additives. Benzoic acid led to the formation of 1,4-addition products under solvent-free conditions, and silver acetate was promoted to the generation of oxidative Heck-type products. Various maleimides and chromones were suitable for this transformation, affording the desired products with good to excellent yields in a short reaction time. To understand the mechanism of this reaction, deuteration studies and control experiments have been performed.

The plant immune system is fundamental to plant survival in natural ecosystems and productivity in crop fields. Substantial evidence supports the prevailing notion that plants possess a two-tiered innate immune system, called pattern-triggered immunity (PTI) and effector-triggered immunity (ETI). PTI is triggered by microbial patterns via cell surface-localized pattern-recognition receptors (PRRs), whereas ETI is activated by pathogen effector proteins via mostly intracellularly-localized receptors called nucleotide-binding, leucine-rich repeat proteins (NLRs)1-4. PTI and ETI are initiated by dist 30 inct activation mechanisms and are considered to act independently and have evolved sequentially5,6. Here we show that, contrary to the perception of PTI and ETI being separate immune signaling pathways, Arabidopsis PRR/co-receptor mutants, fls2/efr/cerk1 and bak1/bkk1/cerk1 triple mutants, are greatly impaired in ETI responses when challenged with incompatible Pseudomonas syrinage bacteria. We further show that the NADPH oxidase (RBOHD)-mediated production of reactive oxygen species (ROS) is a critical early signaling event connecting PRR and NLR cascades and that PRR-mediated phosphorylation of RBOHD is necessary for full activation of RBOHD during ETI. Furthermore, NLR signaling rapidly augments the transcript and protein levels of key PTI components at an early stage and in a salicylic acid-independent manner. Our study supports an alternative model in which PTI is in fact an indispensable component of ETI during bacterial infection, implying that ETI halts pathogen infection, in part, by directly co-opting the anti-pathogen mechanisms proposed for PTI. This alternative model conceptually unites two major immune signaling pathways in the plant kingdom and mechanistically explains the long-observed similarities in downstream defense outputs between PTI and ETI.

Plants utilize nucleotide-binding, leucine-rich repeat receptors (NLRs) to detect pathogen effectors, leading to effector-triggered immunity. The NLR ZAR1 indirectly recognizes the Xanthomonas campestris pv. campestris effector AvrAC and Pseudomonas syringae effector HopZ1a by associating with closely related receptor-like cytoplasmic kinase subfamily XII-2 (RLCK XII-2) members RKS1 and ZED1, respectively. ZAR1, RKS1, and the AvrAC-modified decoy PBL2UMP form a pentameric resistosome in vitro, and the ability of resistosome formation is required for AvrAC-triggered cell death and disease resistance. However, it remains unknown whether the effectors induce ZAR1 oligomerization in the plant cell. In this study, we show that both AvrAC and HopZ1a can induce oligomerization of ZAR1 in Arabidopsis protoplasts. Residues mediating ZAR1–ZED1 interaction are indispensable for HopZ1a-induced ZAR1 oligomerization in vivo and disease resistance. In addition, ZAR1 residues required for the assembly of ZAR1 resistosome in vitro are also essential for HopZ1a-induced ZAR1 oligomerization in vivo and disease resistance. Our study provides evidence that pathogen effectors induce ZAR1 resistosome formation in the plant cell and that the resistosome formation triggers disease resistance.

Modelling nutrient release profiles from a population of controlled release fertiliser (CRF) is essential for synchronising their release with plant nutrient requirements. A mechanistic model succeeds in describing the release profiles from a single granule. Yet, a large deviation will appear when it is used for a population of CRF due to the large variation in a CRF population. Least Squares Support Vector Machines (LS-SVM) that incorporated the variation were used to predict nutrient release from a CRF population using the photoacoustic spectra of the coating, coating percentage, and frequency distribution of granule radii as inputs. The predicted release profiles were in good agreement with observations both for ‘S’ and inverse ‘L’ release patterns. LS-SVM model was effective and accurate in modelling nutrient release from a CRF population.

A series of ceria-modified Cu-USY catalysts were prepared by a co-impregnation method and tested towards the selective reduction of NOx with NH3. A 5Cu-8Ce-USY catalyst with 8 wt% Ce content showed optimum low-temperature activity, and the widest NO conversion temperature window (160–410 °C) of operation, which these features are related to the enhanced redox ability and Cu+ species concentration in the sodalite cage compared to the Cu-USY catalyst. In addition, Lewis acid sites on the surface of Cu-Ce-USY catalysts were found to play a key role for its excellent SCR performance. The ceria-modified Cu-USY catalysts with enhanced low-temperature (120–170 °C) deNOx performance make them highly promising candidates for practical applications in controlling NOx emissions.

Plants have evolved multiple defense strategies to cope with pathogens, among which plant immune signaling that relies on cell-surface localized and intracellular receptors takes fundamental roles. Exciting breakthroughs were made recently on the signaling mechanisms of pattern recognition receptors (PRRs) and intracellular nucleotide-binding site (NBS) and leucine-rich repeat (LRR) domain receptors (NLRs). This review summarizes the current view of PRRs activation, emphasizing the most recent discoveries about PRRs' dynamic regulation and signaling mechanisms directly leading to downstream molecular events including mitogen-activated protein kinase (MAPK) activation and calcium (Ca2+ ) burst. Plants also have evolved intracellular NLRs to perceive the presence of specific pathogen effectors and trigger more robust immune responses. We also discuss the current understanding of the mechanisms of NLR activation, which has been greatly advanced by recent breakthroughs including structures of the first full-length plant NLR complex, findings of NLR sensor-helper pairs and novel biochemical activity of Toll/interleukin-1 receptor (TIR) domain.

Stomata, the pores formed by a pair of guard cells, are the main gateways for water transpiration and photosynthetic CO2 exchange, as well as pathogen invasion in land plants. Guard cell movement is regulated by a combination of environmental factors, including water status, light, CO2 levels and pathogen attack, as well as endogenous signals, such as abscisic acid and apoplastic reactive oxygen species (ROS). Under abiotic and biotic stress conditions, extracellular ROS are mainly produced by plasma membrane-localized NADPH oxidases, whereas intracellular ROS are produced in multiple organelles. These ROS form a sophisticated cellular signaling network, with the accumulation of apoplastic ROS an early hallmark of stomatal movement. Here, we review recent progress in understanding the molecular mechanisms of the ROS signaling network, primarily during drought stress and pathogen attack. We summarize the roles of apoplastic ROS in regulating stomatal movement, ABA and CO2 signaling, and immunity responses. Finally, we discuss ROS accumulation and communication between organelles and cells. This information provides a conceptual framework for understanding how ROS signaling is integrated with various signaling pathways during plant responses to abiotic and biotic stress stimuli.

Field experiments were conducted to assess the effects of straw incorporation (SI) on total organic carbon (TOC) and labile organic C fractions at 0–0.4 m depths and on crop yields in a rice–wheat-cropping system at two sites [Jiangyan (JY) and Guangde (GD)] from 2012 to 2016. Two treatments were established at each site: straw removal (SR) and SI. Soil samples were collected from depths of 0–0.1, 0.1–0.2 and 0.2–0.4 m. Dissolved organic C (DOC), microbial biomass C (MBC), easily oxidizable C (EOC) and particulate organic C (POC) were measured. A C pool management index (CPMI) was also calculated. Straw incorporation increased average rice and wheat grain yields by 11.6 and 11.1%, respectively, at the JY site. However, at the GD site, no significant differences were found in average crop yields between treatments. The TOC at 0–0.2 m was 13.8–22.3% higher under SI than under SR at the JY site, whereas 32.2% higher value was found only at 0–0.1 m at the GD site. DOC, MBC and EOC at 0–0.1 m, and POC at 0–0.2 m were all greater under SI than under SR at both sites. Thus, POC is a more sensitive indicator of changes in TOC induced by SI in topsoil. Straw incorporation led to a 1.4–1.6 times higher CPMI at 0–0.1 m at both sites. We conclude that SI is an effective practice for improving crop productivity and TOC sequestration in a rice–wheat-cropping system, although the site specificity of this practice should be considered before it is adopted.

Plants deploy numerous cell surface-localized pattern-recognition receptors (PRRs) to perceive host- and microbe-derived molecular patterns that are specifically released during infection and activate defense responses. The activation of the mitogen-activated protein kinases MPK3, MPK4, and MPK6 (MPK3/4/6) is a hallmark of immune system activation by all known PRRs and is crucial for establishing disease resistance. The MAP kinase kinase kinase (MAPKKK) MEKK1 controls MPK4 activation, but the MAPKKKs responsible for MPK3/6 activation downstream of diverse PRRs and how the perception of diverse molecular patterns leads to the activation of MAPKKKs remain elusive. Here, we show that two highly related MAPKKKs, MAPKKK3 and MAPKKK5, mediate MPK3/6 activation by at least four PRRs and confer resistance to bacterial and fungal pathogens in Arabidopsis thaliana The receptor-like cytoplasmic kinases VII (RLCK VII), which act downstream of PRRs, directly phosphorylate MAPKKK5 Ser-599, which is required for pattern-triggered MPK3/6 activation, defense gene expression, and disease resistance. Surprisingly, MPK6 further phosphorylates MAPKKK5 Ser-682 and Ser-692 to enhance MPK3/6 activation and disease resistance, pointing to a positive feedback mechanism. Finally, MEKK1 Ser-603 is phosphorylated by both RLCK VII and MPK4, which is required for pattern-triggered MPK4 activation. These findings illustrate central mechanisms by which multiple PRRs activate MAPK cascades and disease resistance.

The plant elicitor peptides (Peps), a family of damage/danger-associated molecular patterns (DAMPs), are perceived by two receptors, PEPR1 and PEPR2, and contribute to plant defense against pathogen attack and abiotic stress. Here, we show that the Peps-PEPR signaling pathway functions in stomatal immunity by activating guard cell anion channels in Arabidopsis thaliana. The mutant plants lacking both PEPR1 and PEPR2 (pepr1 pepr2) displayed enhanced bacterial growth after being sprayed with Pseudomonas syringae pv tomato (Pst) DC3000, but not after pathogen infiltration into leaves, implicating PEPR function in stomatal immunity. Indeed, synthetic Arabidopsis Peps (AtPeps) effectively induced stomatal closure in wild-type but not pepr1 pepr2 mutant leaves, suggesting that the AtPeps-PEPR signaling pathway triggers stomatal closure. Consistent with this finding, patch-clamp recording revealed AtPep1-induced activation of anion channels in the guard cells of wild-type but not pepr1 pepr2 mutant plants. We further identified two guard cell-expressed anion channels, SLOW ANION CHANNEL1 (SLAC1) and its homolog SLAH3, as functionally overlapping components responsible for AtPep1-induced stomatal closure. The slac1 slah3 double mutant, but not slac1 or slah3 single mutants, failed to respond to AtPep1 in stomatal closure assays. Interestingly, disruption of OPEN STOMATA1 (OST1), an essential gene for abscisic acid-triggered stomatal closure, did not affect the AtPep1-induced anion channel activity and stomatal response. Together, these results illustrate a DAMP-triggered signaling pathway that, unlike the flagellin22-FLAGELLIN-SENSITIVE2 pathway, triggers stomata immunity through an OST1-independent mechanism.

Receptor kinases (RKs) are of paramount importance in transmembrane signaling that governs plant reproduction, growth, development, and adaptation to diverse environmental conditions. Receptor-like cytoplasmic kinases (RLCKs), which lack extracellular ligand-binding domains, have emerged as a major class of signaling proteins that regulate plant cellular activities in response to biotic/abiotic stresses and endogenous extracellular signaling molecules. By associating with immune RKs, RLCKs regulate multiple downstream signaling nodes to orchestrate a complex array of defense responses against microbial pathogens. RLCKs also associate with RKs that perceive brassinosteroids and signaling peptides to coordinate growth, pollen tube guidance, embryonic and stomatal patterning, floral organ abscission, and abiotic stress responses. The activity and stability of RLCKs are dynamically regulated not only by RKs but also by other RLCK-associated proteins. Analyses of RLCK-associated components and substrates have suggested phosphorylation relays as a major mechanism underlying RK-mediated signaling.

Snow-cover parameters are important indicator factors for hydrological models and climate change studies and have typical vertical stratification characteristics. Remote sensing can be used for large-scale monitoring of snow parameters. InSAR (Interferometric Synthetic Aperture Radar) technology has advantages in detecting the vertical structure of snow cover. As a basis of snow vertical structure detection using InSAR, a scattering model can reveal the physical process of interaction between electromagnetic waves and snow. In recent years, the InSAR scattering model for single-layer snow has been fully studied; however, it cannot be applied to the case of multi-layer snow. To solve this problem, a multi-layer snow scattering mode is proposed in this paper, which applies the QCA (Quad-Crystal Approximation) theory to describe the coherent scattering characteristics of snow and introduces a stratification factor to describe the influence of snow stratification on the crosscorrelation of SAR echoes. Based on the proposed model, we simulate an InSAR volumetric correlation of different types of multi-layer snow at the X band (9.6 GHz). The results show that this model is suitable for multi-layer snow, and the sequence of sub-layers of snow has a significant influence on the volumetric correlation. Compared to the single layer model, the multi-layer model can predict a polarization difference in the volumetric correlation more accurately and thus has a wider scope of application. To make the model more available for snow parameter inversion, a simplified multi-layer model was also developed. The model did not have polarization information compared to that of the full model but showed good consistency with the full model. The phase of the co-polarization InSAR volumetric correlation difference is more sensitive to snow parameters than that of the phase difference of the co-polarization InSAR volumetric correlation and more conducive to the development of a parameter-inversion algorithm. The model can be applied to deepen our understanding of InSAR scattering mechanisms and to develop a snow parameter inversion algorithm.

Arabidopsis heterotrimeric G proteins regulate diverse processes by coupling to single-transmembrane receptors. One such receptor is the FLS2 receptor kinase, which perceives bacterial flagellin epitope flg22 to activate immunity through a class of cytoplasmic kinases called BIK1/PBLs. Unlike animal and fungal heterotrimeric G proteins that are activated by a ligand-induced guanine nucleotide exchange activity of seven-transmembrane G protein-coupled receptors (GPCRs), plant heterotrimeric G proteins are self-activating. How plant receptors regulate heterotrimeric G proteins in response to external ligands remains unknown. Here we show that RGS1, a GTPase accelerating protein, maintains Arabidopsis G proteins in an inactive state in complex with FLS2. Activation of FLS2 by flg22 induces a BIK1/PBL-mediated phosphorylation of RGS1 at Ser428 and Ser431 and that promotes RGS1 dissociation from the FLS2-G protein complex. This relieves G proteins from the RGS1-mediated repression and enables positive regulation of immune signaling. We additionally show that RGS1 is similarly regulated by multiple immune receptors. Our results uncover ligand-induced de-repression as a mechanism for G protein signaling in plants that is distinct from previously reported mechanism underlying the activation of heterotrimeric G proteins in other systems.

Supraglacial debris complicates the melting state of debris-covered glaciers, and whether debris increases or decreases the rate of glacier melt is ambiguous according to different observations. In this paper, we aim to determine the potential factors that influence changes in thickness of debris-covered glaciers. First, we present the thickness changes of a large debris-covered glacier in the Tienshan Mountain using high-resolution Digital Elevation Model (DEM) data from three periods in 2000, 2009 and 2013. It is shown that the thickness changes differ greatly over the debris-covered portions of the glacier. These debris-covered regions can be divided into three parts along the glacier axis according to the rate of thickness change. Specifically, these parts include the zone of minimal change, the zone of heavy thinning, and the zone of slight thinning. Detailed information on the closely related factors, including the debris thickness, which was measured across the whole glacier during our field work, and the presence of ice cliffs and supraglacial lakes detected on high-resolution satellite images, are combined to determine the reasons for the differences in melting state among the three zones. The results show that the thickness changes of the debris-covered glacier are jointly influenced by debris thickness and the presence of ice cliffs and supraglacial lakes; moreover, the dominant factor differs among the different zones. The critical debris thickness, which mostly appears in the minimal change zone and accelerates glacier melting, as confirmed through field observations, is not associated with glacier thinning because its location is close to the accumulation zone. The regions where the rates of thinning are greatest coincide with the regions where the ice cliffs are densest. Where the debris is thicker than 1 m on average, the glacier is still thinning slightly due to the presence of ice cliffs and lakes. It is proven that the quantity and area of the ice cliffs and supraglacial lakes is the key to understanding the melting rate of debris covered glacier.

Constitutive and dynamic protein-protein interactions are fundamental to all aspects of cellular processes. Compared to other techniques measuring protein-protein interactions in plants, the luciferase complementation assay has a number of advantages: it detects plant protein-protein interactions in real time, requires little hands-on manipulation of samples, is highly quantitative, has extremely low background, and can be easily scaled up for high-throughput interactome studies. Here, we describe a protocol that includes two alternate data collection methods to quantify luminescence results based on Agrobacterium-mediated transient luciferase expression in Nicotiana benthamiana. One data collection method employs a charge-coupled device imaging system that allows the interactions to be presented as images, and the other employs a luminometer, which enables the assay to be conducted in a 96-well plate. Technical parameters related to frequently encountered problems and common errors, presented here, are important for performing this assay successfully. © 2018 by John Wiley & Sons, Inc.

Point placement of urea is an efficient technology to improve urea use efficiency in transplanted rice (Oryza sativa L.), but it is largely unknown how nutrient composition in the point placement and the distance from placement site to the plant influence rice root distribution and growth, nutrient uptake, and rice grain yield. A controlled greenhouse experiment was conducted using both N- and P-deficient soil with point placement of N only or N and P together (N + P) at a distance close to or far from the plant, in comparison to an N-spilt application and a no-N control. Both nutrient composition and distance significantly affected rice root growth. Compared with the N point placement, the N + P point placement led to smaller root length and mass densities, higher specific root length (SRL) around the placement site, smaller root system, higher straw mass and grain yield, and higher N and P uptake. The difference between the N + P and N point placements was greater when close to the plant than when far from the plant. It is suggested that higher SRL around the placement site is essential for improving nutrient uptake and rice grain yield, and simultaneous point placement of N and P has a synergistic effect on rice growth.

A bimetallic carbide enhanced nitrogen/phosphor co-doped graphite nanocomposite (Co3W3C/NPG) is proposed for the first time as a highly active and stable non-noble-metal catalyst for the oxygen reduction reaction (ORR). The newly multi-component Co3W3C/NPG catalysts presented a high on-set potential of 0.92 V and little decreased half-wave potential of 5 mV after 8000 cycles in the O2-saturated 0.1 M HClO4 electrolyte. The electron transfer number was calculated to be above 3.9 before and after 8000 cycles, indicating that the Co3W3C/NPG catalyst behaves as a steady 4e oxygen reductant in acidic medium.

Determination of soil organic matter (SOM) is extremely important for diagnosing the fertility status of agricultural soils. Thus, fast and efficient approaches are needed to aid soil fertilization assessment. In this work, the method proposed is based on the combination of mid-infrared attenuated total reflection (FTIR-ATR) and dispersive Raman spectroscopy, as a rapid and nondestructive alternative to traditional chemical analysis. The ability of both two individual and the fused spectroscopy in SOM prediction was tested. Partial least squares regression (PLSR) was used to construct predictive models to correlate soil spectra with SOM content. Simple data fusion was accomplished by concatenating the principal components of the two spectra. The predictive performance was not essentially improved, and even decreased for the fused ATR-Raman spectra based on the simple fusion strategy. Better results were obtained with the advanced method of data fusion, which is, concatenating the selected variables of the two spectroscopic techniques after the step of variable selection by competitive adaptive reweighted sampling (CARS). The results showed that the RMSEP of the prediction model was decreased using both the individual and fused spectra data, combining with the CARS algorithm. Models based on fused spectra data with selected variables had the best performance in accuracy of SOM prediction. Therefore, the fused technology of ATR and Raman spectroscopy is a promising approach to predict soil properties, such as SOM, with the advantage of simple preparation of soil samples.

Large areas of the arable soils of the world are deficient in potassium (K) due to the low application rate of K fertilizer. However, current soil test methods cannot precisely determine soil available K changes. From 2009 to 2014, a field experiment was conducted in a rice–wheat cropping system in the Yangtze Plains using five K rates. The objectives were to determine the responses of wheat and rice yield to different K rates and to compare the soil available K changes extracted by three methods (ammonium acetate (NH4OAc), boiling nitric acid (HNO3), and sodium tetraphenylboron (NaTPB)). Long periods without application of K fertilizer markedly decreased wheat yield by 47% and rice yield by 15% compared with local farmers’ K practices (FKP, 90 and 120 kg K2O ha−1 for wheat and rice, respectively). The FKP achieved optimal yields for wheat and rice; however, only 160% of FKP achieved a positive K balance for the cropping system. Soil-extractable K consistently decreased with increasing cropping rotations where the K rate was below 160% FKP for the three extraction methods. The extractable and changed amounts for the NH4OAC and HNO3 methods were significantly lower than that for the NaTPB method. The soil K changes for NaTPB were closer to the theoretical soil available K changes (TAKC) derived from an apparent K balance. The NaTPB method could be useful for accurately determining changes in soil available K in cropping systems.

Advanced technologies, such as infrared spectroscopy, have been applied to develop rapid, cheap but accurate methods for the analysis of soil matter organic (SOM). However, the unsatisfied prediction accuracy resulted from heavy soil heterogeneity limits the practical application. In our previous work, soil identification based self-adaptive partial least squares model (SAM), which was built using identification algorithm and the partial least square regression (PLSR), makes it possible for a wide use. However, soil identification in the SAM needs be further optimized. In this study, we designed an advanced optimal self-adaptive partial least squares model (OPT-SAM), a more general model to predict SOM. 597 soil samples from China with large variances were collected, and the soil spectra were recorded using Fourier transform mid-infrared photoacoustic spectroscopy (FTIR-PAS). Five typical algorithms (Correlation coefficients (CC), Euclidean distance (ED), Mahalanobis distance (MD), Angle cosine (AC), and k-medoids (KM)) were considered for the identification in the SAM model. The results demonstrated that the performances of CC-SAM, ED-SAM, MD-SAM, AC-SAM were significantly improved in comparison with no identification based SAM (NI-SAM), but KI-SAM showed a poor prediction. ED-SAM (R 2 = 0.8890, RMSEP = 7.00 g kg −1 , RPD = 2.96) indicated the highest accuracy and robustness in all algorithms, which was an optimal model for soil identification and prediction, and CC-SAM (R 2 = 0.8572, RMSEP = 7.89 g kg −1 , RPD = 2.44) was an alternative choice, especially for prediction with different soil types.

Polyacrylate polymer (PA) has been widely applied in coating products for decades. Recently, it has been used in controlled-release fertilizers. Nano FeIII-tannic acid modified PA (PA-Fe) provides a better nutrient controlled release performance than conventional PA. In this work, a preliminary database of molecular and elemental information about the polymer was obtained using FTIR-PAS (Fourier transform infrared photoacoustic spectroscopy) and LIBS (laser-induced breakdown spectroscopy), respectively. The PA-Fe polymer contained more hydrophobic groups (–CH3) and fewer hydrophilic groups (–COOR, –COOH) than PA. More elements were detected for PA-Fe than PA. LIBS was useful to identify and classify PA and PA-Fe samples using principal component analysis. The combination of spectroscopic results and a film formation process model explained the lower nutrient release rate of PA-Fe. These results showed the strong analytical capabilities of FTIR-PAS combined with LIBS for identifying and characterizing modified PA.

Large-scale glacier area expansion or shrinkage is among the most conspicuous indicators of regional and global climate change. Glacier extraction from satellite images is an essential step in large-scale area change monitoring. However, glacier extraction is usually influenced by cloud cover and seasonal snow, and thus far, there is no effective and automatic method to monitor glacier area change in large regions. In this study, a new method ‘multi-temporal minimum NDSI composite’ is proposed for clean glacier and nonseasonal snow extraction, and the results agree well with the glacier inventory (excluding the debris part), except in Himalayan regions where non-seasonal snow exists widely out of glaciers. This method is also used to estimate the glacier and nonseasonal snow area changes in High Mountain Asia (HMA) over the past 29 years. With this method, we can use abundant Landsat images of summer seasons from continuous years to composite a cloud-free and seasonal snow-free glacial image pixel by pixel. Glacial maps for the whole HMA are produced every 10 years beginning in 1990, so glacier changes are presented in different subregions and periods. The number of images which is used to composite a glacial map in each pixel is also given for uncertainty analysis. According to the results, the clean glacier and nonseasonal snow area in HMA decreased by −0.43 ± 0.19%/a during 1990–2018 but had high temporal and spatial heterogeneity. Clean glacier and nonseasonal snow area decreased rapidly during 1990–2000, slowed down during 2000–2010, and then sped up during 2010–2018. The fastest reductions were in Hengduan Shan at rates of approximately −1.05 ± 0.09%/a, and the only area with growth (at a rate of 0.50 ± 0.11%/a) was in West Kun Lun during 1990–2018.

Active soil organic carbon (SOC) fractions play a key role in agricultural soil fertility. However, the effects of potassium application and straw incorporation on SOC and active SOC fractions as well as the relationships among these factors in a rice–wheat system are less well-studied. Hence, the objective of this study was to analyse the effects of potassium fertilization and straw incorporation on SOC sequestration, active carbon fractions, and crop yields in a long-term (6 years) field experiment. Four treatments were examined: no addition of potassium fertilizer and straw (CK), straw incorporation only (SI), potassium-fertilizer application only (K), and straw incorporation plus a recommended amount of potassium fertilizer (SI + K). SOC, dissolved organic carbon (DOC), light fraction organic carbon (LFOC), microbial biomass carbon (MBC), easily oxidizable carbon (EOC), crop yields, and the carbon pool management index (CMI) were determined. After 6 years, SOC content and labile C fractions in the SI treatment increased significantly, by 7.95–25.0 % and 23.6–185 %, respectively, compared to the CK treatment. Significant and positive correlations were observed between SOC, DOC, LFOC, MBC, EOC, and the CMI (r = 0.449–0.899, P < 0.01). Among the five C fractions, LFOC, DOC, and EOC were the most sensitive indicators of changes in SOC induced by incorporating straw with or without potassium fertilizer. The highest SOC contents and labile C fractions were observed in the SI + K treatment. Rice yields increased from 8.55 and 7.59 t ha⁻¹ in the CK plots to 9.56 and 8.54 t ha⁻¹ with SI + K at Guangde (GD) and Jiangyan (JY) sites, respectively. Wheat yields increased from 0.53 and 5.33 t ha⁻¹ in the CK plots to 5.86 and 6.43 t ha⁻¹ with SI + K at GD and JY sites, respectively. Overall, based on crop yields and C storage, straw incorporation in combination with a moderate amount of potassium fertilizer appears to be the best practice for improving soil fertility and productivity in the rice-wheat cropping system.

The high potassium (K)-fixing capacity of calcareous soils with homogeneous K supply limits crop K concentration. The objective of this study was to determine the increase in the leaf K concentration of tobacco (Nicotiana tabaccum L.) with a heterogeneous K supply. Two field experiments were conducted from 2013 to 2015 with five K rates applied in homogeneous environments and one K rate applied in varying fractions of soil volume (from 0% to 100%) in heterogeneous environments. Under ridge culture, leaf biomass was not significantly affected by homogeneous (K rate) or heterogeneous (patch size) K management. Under homogeneous conditions, increasing the K supply to three times the standard rate used by farmers (249 kg K ha−1) increased leaf K concentration significantly, but the effect was limited and not cost-effective. Heterogeneous supply of K fertilizer at the standard K rate in patches of 0–40% of soil volume outperformed homogeneous K supply in terms of leaf K concentrations. Furthermore, K fertilizer mixed in intermediate soil volume fractions of 1–20% resulted in higher leaf K concentrations than the smallest (0%) and larger (30–40%) soil fractions. However, such K-rich patch application should be managed precisely with specific placement due to the sharp reduction in available K with increasing distance from the fertilizer. To maximize the sorption of immobile K, the match between the uptake volume of the rhizosphere and the area available for K diffusion is important.

A full understanding of radar backscattering characteristics and their seasonal variations is one of the important ways to analyse the growth conditions in wetlands. This research simulated seasonal C-band and L-band synthetic aperture radar (SAR) backscattering from reed marshes using a refined version of the electromagnetic (REM) model, which was first validated by time series of multimode SAR observations at the experimental site used. Then, two factors including sensor parameters and vegetation structure, which influence the temporal evolution of the radar response from reed marshes, were assessed. The results demonstrate that the radar response is closely related to growth processes in the reed marsh. At the early growth stage when reed marshes are sparse, the double-bounce mechanism was dominant at all the incidence angles of C-band radar, but for L-band radar, strong specular reflection was produced from the smooth water if the incidence angle is lower than 25°. It was also found that the s...

Crop production must be increased in order to ensure a sustainable food supply for the growing world population. Controlled-release urea (CRU) improves nutrient use efficiency and saves labor, but its use in crop production is limited due to its high cost. Bulk blending urea (BBU) consists of both CRU and conventional urea and could be an excellent substitute or replacement for CRU. Nevertheless, its economic benefits and soil environment impact are unknown. A three-year field experiment was conducted to investigate the effects of two different nitrogen management practices in terms of economic benefits, soil mineral nitrogen availability, aggregate stability, and soil microbial communities. Split applications of conventional urea (UREA) and a single application of BBU were tested on winter wheat (Triticum aestivum L.) and summer maize (Zea mays L.) in the North China Plain between 2010 and 2013. Crop yields were measured after each harvest and soil environmental parameters were determined after the three-year crop sequence. Relative to UREA, BBU significantly increased net revenue, soil inorganic nitrogen concentration, and the functional diversity of the soil microbial community without adverse effects on the soil bacterial community composition. On the other hand, BBU reduced the amount of soil macro-aggregates and the mean weight diameter value of soil water-stable aggregates. Although BBU showed great potential for improving wheat–maize cropping systems in the North China Plain, future studies should focus on optimizing the nitrogen dosage and the CRU ratio in BBU to decrease nitrogen leaching, avoid soil aggregate deterioration, and maintain crop yield.

Reactive oxygen species (ROS) are widely produced in different cellular compartments under both biotic and abiotic stress conditions. ROS play a central role in plant signaling and regulate diverse cellular processes. Recent advances are shedding new light on sophisticated mechanisms controlling ROS biogenesis and signaling in plant immunity. In this review, we summarize our current understanding of the regulation of apoplastic ROS production in response to microbial molecular patterns and draw comparison with abscisic acid (ABA)-induced apoplastic ROS. We also discuss how ROS act as signal molecules to regulate cellular activities using stomatal movement as an example.

Split application of nitrogen (N), applied by broadcasting, is both time consuming and inconvenient; yet it is widely practised for wheat. Simplified N fertilization is necessary for wheat in south-eastern China. One-time band application was compared with split application using three doses of N (150, 195, and 240 kg ha−1) in 2014/2015 and 2015/2016. Grain yield and N-use efficiency of winter wheat were determined over two consecutive seasons. A corresponding micro-plot trial using 15N-labelled urea was conducted only in 2015/2016 to measure the fate of urea-15N. The two methods showed no difference in grain yield, except at 240 kg ha−1 of N in 2014/2015. The average grain N concentration (18.2 g kg−1) was slightly lower in band application than that in broadcast application (19.2 g kg−1), but there was no significant difference (P > 0.05). In 2014/2015, N apparent recovery efficiency ranged from 33.1 to 49.9%; N agronomic efficiency, from 8.9 to 38.9 kg kg−1; and N partial factor productivity, from 23.6 to 38.4 kg kg−1. In 2015/2016, the corresponding values were 29.4–38.6%, 13.5–38.6, and 24.3–33.9 kg kg−1. In the micro-plot trial, compared to split application, fertilizer N recovery in winter wheat in one-time band application was lower by 26.5% and increased the unaccounted-N loss by 21.7%. Thus, considering environmental impacts, one-time band application of N at sowing is not a suitable alternative to broadcast application in split doses for winter wheat in the loamy soils of south-eastern China.

Additions of nitrogen (N) and water might have an interactive effect on the structure of the soil microbial community. The effects and importance of a fluctuating natural precipitation regime on the soil microbial community in a semiarid meadow steppe are very variable and less well known. On a Stipa baicalensis Rosh. meadow steppe, we used phospholipid fatty acid (PLFA) analysis to evaluate the effects of increased precipitation, addition of nitrogen and precipitation regime in regulating the structure of the microbial community. The experiment had a complete randomized block design with additions of N of 0, 5 and 10 g N m−2 year−1 and of water of 15 or 30% above the natural precipitation from 2010 to 2012. Additional water and number of years had interactive effects on the soil's microbial community structure. The indirect effects of water and N on soil properties such as pH might explain, at least in part, the changes in microbial groups. Additional water significantly decreased PLFAs for most microbial groups in the dry year, but had no effect in the wet year. The results reflected fluctuation in the natural precipitation regime during two hydrologically contrasting years. Changes in the structure of the soil microbial community might depend on variation in interannual precipitation on meadow steppe. Overall, this study emphasizes the importance of the precipitation regime for the soil's microbial community structure. Increases in natural precipitation will weaken the negative effects of nitrogen fertilizers on the grassland ecosystem in future. Highlights Effects of fluctuating natural precipitation and additions of nitrogen on soil's microbial community structure. Structure of soil's microbial community might depend on variation in interannual precipitation on meadow steppe. Increases in natural precipitation weaken the negative effects of nitrogen fertilizers on the grassland ecosystem. Precipitation regime has an important effect on soil's microbial community structure.

The normal perforation of monolithic and layered Weldox 460 E steel targets by conical projectiles is investigated with smoothed particle hydrodynamics (SPH) simulation and analytical method. A series of SPH simulations are performed for the perforation of monolithic targets with different thicknesses and layered targets with different total thicknesses and layering schemes. According to the simulated results, an empirical relation between ballistic limit velocity and target thickness is determined for monolithic target, and the variation of ballistic resistance with number of layers, total thickness and thickness configuration is revealed for layered target. Based on the established empirical relation for monolithic target, an analytical method is used to analyze the ballistic resistance of layered targets with different total thicknesses and layering schemes. The analytical results are compared with SPH simulation results, and the applicability and accuracy of the analytical method for the present problems are discussed.

With increased demand for Cordyceps sinensis it needs rapid methods to meet the challenge of identification raised in quality control. In this study Cordyceps sinensis from four typical natural habitats in China was characterized by depth-profiling Fourier transform infrared photoacoustic spectroscopy. Results demonstrated that Cordyceps sinensis samples resulted in typical photoacoustic spectral appearance, but heterogeneity was sensed in the whole sample; due to the heterogeneity Cordyceps sinensis was represented by spectra of four groups including head, body, tail and leaf under a moving mirror velocity of 0.30cms-1. The spectra of the four groups were used as input of a probabilistic neural network (PNN) to identify the source of Cordyceps sinensis, and all the samples were correctly identified by the PNN model. Therefore, depth-profiling Fourier transform infrared photoacoustic spectroscopy provides novel and unique technique to identify Cordyceps sinensis, which shows great potential in quality control of Cordyceps sinensis.

Acrylic latexes are valuable waterborne materials used in controlled-release fertilizers. Controlled-release urea coated with these latexes releases a large amount of nutrients, making it difficult to meet the requirement of plants. Herein, FeIII–tannic acid (TA) complexes were blended with acrylic latex and subsequently reassembled on a surface of polyacrylate particles. These complexes remarkably retarded the release of urea (the preliminary solubility was decreased from 22.3 to 0.8%) via decreasing the coating tackiness (Tg was increased from 4.17 to 6.42 °C), increasing the coating strength (tensile stress was improved from 3.88 to 4.45 MPa), and promoting the formation of denser structures (surface tension was decreased from 37.37 to 35.94 mN/m). Overall, our findings showed that a simple blending of FeIII–TA complexes with acrylic latex produces excellent coatings that delay the release of urea, which demonstrates great potential for use in controlled-release fertilizers coated with waterborne polymers.

Improper application of nitrogen (N) has led to high N losses and low N use efficiency in the lower reaches of Yangtze River in China. An effective method to solve such problems is the deep fertilized N in root zone (RZF). Limited information is available on the effect of RZF on the uptake of macronutrients (N, P and K) and rice yield. Field experiments, conducted from 2014 to 2015, compared the farmer fertilizer practice (FFP, with 225 kg ha−1 of N, split into three doses) and RZF using the same rate but placing N 5 cm away from rice roots in holes 10 cm deep (RZF10) or 5 cm deep (RZF5) as a single application. The highest mean yield (10.0 t ha−1) was obtained in RZF10, which was 19.5% more than that in FFP. Root zone fertilization of urea (whether 10 cm deep or 5 cm deep) resulted in greater accumulation of N, P and K in stem, leaf sheaths, leaf blades and grains compared to that in FFP in sandy and in loam soils. The uptake of N, P and K was the highest in RZF10 (average at 176.7, 66.2 and 179.1 kg ha−1, respectively), higher than that in FFP by 45.0, 17.0 and 22.6%, respectively. N apparent recovery efficiency was markedly higher in RZF10 (53.1%) than in FFP (27.5%). RZF10 significantly increased the N, P, K uptake compared with FFP under different N rates in both sandy and loam soils. These results suggest that the N, P and K input amount should be re-determined under RZF.

Straw return is an effective management practice for improving soil fertility and sustaining crop productivity in agro-ecosystems. A field experiment was conducted to investigate the effects of short-term (three-year) crop straw return on soil organic carbon fractions and microbial communities in a rice–wheat cropping system at three sites from central to eastern parts of China. Two treatments were established at each site: no straw return (N) and straw return (S). Compared to N treatment, S treatment significantly increased concentrations of total organic carbon (TOC, except for Qujialing site), dissolved organic C (DOC) and microbial biomass C (MBC), but did not significantly affect the easily oxidizable C content in the three sites. Soil light fraction, light fraction organic C and particulate organic C were higher for S than N treatment by 28–52% in both Guangde and Jiangyan, while these values were not significantly different between N and S treatment in Qujialing. Soil microbial community compositions of all three sites were changed with straw return. Crop straw return significantly increased total phospholipid fatty acid (PLFA), bacterial biomass and actinomycete biomass by 52, 75 and 56% in Jiangyan, but had no significant effects on PLFAs in both Qujialing and Guangde, compared to N treatment. MBC and TOC were the two main factors affecting microbial communities under short-term crop straw return. Our results demonstrated that DOC and MBC were the most sensitive indictors for assessing changes of SOC under short-term straw return in the rice–wheat cropping system, and soil properties in response to straw return were different at the three sites.

Colorimetry is a conventional method for the determination of soil nitrification rates, and it demands pretreatments and chemical reagents, which make it time and cost consuming. Fourier transform infrared attenuated total reflectance spectroscopy (FTIR-ATR) as a simple and fast method was employed in this study, and the feasibility of determination of nitrate contents by FTIR-ATR under different soil conditions was investigated. It was found that the second-order derivatives of nitrate characteristic bands (1270–1320 cm−1) were proportional to nitrate contents, and an excellent correlation coefficient of 0.9751 was obtained, indicating that FTIR-ATR combined with second-order derivatives could be well used for quantification of nitrate. The nitrate-N contents determined by FTIR-ATR and colorimetry increased with increasing incubation time under different treatments including soil temperature, moisture, pH and nitrogen application rate; in most cases, the values obtained by FTIR-ATR were slightly higher than those obtained by colorimetry after 50% incubation. The abiotic immobilization of nitrate and Fe interference in the colorimetric procedure might contribute to this difference. Thus, FTIR-ATR combined with second-order derivatives can be used as an alternative option for fast determination of nitrate under varied conditions in paddy soils.

Nitrogen isotope labelled technology with mass spectroscopy is commonly used to trace the fate of agricultural N in the environment. However, due to mass spectroscopy's cost, time consumption and long laborious preparation, Fourier transform infrared attenuated total reflection spectroscopy (FTIR-ATR) was employed to detect different isotope labelled nitrates in this study, and the feasibility of this method was investigated in paddy soil. The results showed that the RPD of a partial least squares regression (PLSR) model were 5.69 and 8.15 mg kg−1 for 14NO3–N and 15NO3–N, respectively, and the RMSEP were 5.60 and 3.91 mg kg−1, respectively, which indicated that the method could well predict the nitrate concentration. The model implementation indicated that the total nitrate concentrations from FTIR-ATR and mass spectrometry were almost the same, among which 15N labelled nitrate obtained by ATR was 3.58–10.02 mg kg−1 lower than that from mass spectrometry, while 14N labelled nitrate from ATR was 6.75–13.68 mg kg−1 higher. Compared with a control treatment, the mineralization and release of soil nitrogen were enhanced in a nitrogen treatment. Therefore, the technique of FTIR-ATR can be used as an alternative option in determining isotope labelled nitrate in paddy soil.

Soils are crucial trace evidence that can establish or exclude the relationship between a suspect, victim, or an object at a particular scene, which could contribute to building a case. Laser-induced breakdown spectroscopy (LIBS) and Fourier transform infrared-attenuated total reflectance (FTIR-ATR) spectroscopy have been demonstrated to be effective techniques for soil characterization owing to its being rapid, non-destructive, and convenient analysis with little sample preparation requirements. Therefore, the principles of LIBS and FTIR-ATR techniques for soil forensic analysis in typical soil samples were investigated and their practical feasibility was tested by applying the techniques to forensic soil samples in two criminal cases. Principal component analysis (PCA) of a typical soil sample indicated that five typical soil types were clearly distinguished by LIBS and FTIR-ATR spectra. Variations in the soil elements (i.e., Si, Mg, Al, Ca, K, O, and N) and functional groups (i.e., O H/N H, C C/C O, Si O, CO32−, Al OH, and NH2) are crucial indicators for soil identification. The casework results demonstrated that both LIBS and FTIR-ATR show great potential for forensic soil analysis in future cases.

Bearings used in the wind turbine generators (WTGs) will subject to different degrees of damage during operation, including all kinds of vibration and shock. In this paper, a vibration-based performance degradation assessment method for high-speed shaft wind turbine bearings is proposed using fusion of Hidden Markov Model (HMM) and Fuzzy C-means Model (FCM). The wavelet packet decomposition is used to extract the energy of the wavelet packet nodes of the whole life cycle vibration signal. The autoregressive model (AR) extracts the coefficients and residual of the wavelet packet nodes, and takes the two features as the combined features. The FCM is established using the normal and failure samples and the HMM is established using the normal samples. The two degradation indicators which was obtained by imputing the under test data to FCM and HMM model are input to the FCM model as the input characteristic. Then the performance degradation curve is obtained. Finally, Mahalanobis distance (MD) and FCM models are combined to compare and illustrate. The method combines the advantages of spatial statistical distance model and probabilistic statistical model. Then the WTG bearing’s experimental data are used and the experimental results of AR model combined with FCM model are compared to verify the conclusions of this paper. The experimental analysis shows that the method is consistent with the performance degradation trend of rolling bearings and has certain adaptability.

In this paper, we present the design, fabrication processes, and control of a new biomimetic origami robot-Pillbot inspired by the pill bugs (Armadillidium vulgare). The pill bugs can travel effectively along pile of dead leaves, weeds, and most nature environment and the biological structures of the pill bugs fit the practical, soft and flexible design concept of the soft robotics. This biological case can be applied to soft robots to overcome the real harsh natural environment by three bionic designs: 1) flexible origami exoskeleton, 2) soft internal muscles, 3) bionic pereiopods. The origami exoskeleton is used to protect the body and reduce the friction between the robot surface and the environment. The soft internal muscles support the completion of the corresponding function with the exoskeleton and other structures of the robot. The bionic pereiopods ensure that the Pillbot can perform a variety of crawling movements. As a result, Pillbot can crawl, turn effective in the real environment, and the innovative designs for Pillbot will be applied to soft robots that are used in a harsh realistic environment.