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The thermal conditions of soil are important in practical agricultural production. The characteristics of heat flux, moisture content, thermal conductivity, and other soil parameters vary with temperature. This study uses VADOSE/W to create a model of heat transmission between soil and atmosphere, simulating daily changes in soil temperature using sand mulching. By using the published data to verify the model, the results show that the fitting effect is good and the reliability of the model is verified. We also used this model to determine the temporal and spatial distributions of soil temperature, temperature differences, and a temperature gradient for sand mulching and bare soil during the growing season of spring wheat. These results indicated that the sand mulching preserved heat at night. The difference in temperature at each depth and the temperature gradient became negative with the gradual increase in solar altitude. The difference in soil temperature at each depth and the temperature gradient tended to become positive by 22:00. These results indicated that the sand mulch effectively maintained the soil temperature in the morning and night during the growing season and impeded the transfer of heat at mid-day. This study provides a new method for determining the transfer of heat in sand-mulched soil, which can guide the effective regulation of soil temperature.

Soil-water characteristic curve (SWCC) and soil hydraulic conductivity are important soil hydrodynamic parameters, which are of great significance in production practice. In 128 soil samples collected from 0-20, 20-40 cm layers at sampling scales of 32×32 m, the authors determined the effect of different periods of time on SWCC and soil hydraulic conductivity in fields mulched gravel. The water holding capacity of soil changes dramatically throughout time, with NEW having the maximum water holding capacity. As the planting time increases, the soil water holding capacity decreases. Both van Genuchten (VG) and Gardner models can fit SWCC in different time periods well, but the fitting accuracy of the VG model is higher. Geostatistics and Kriging interpolation are used to study the spatial variability of the VG model parameters of the SWCCs. The parameters θs, α, and n show a strong spatial correlation as a whole and are slightly affected by random factors. The changing trend of soil unsaturated hydraulic conductivity (K(θ)) in gravel-mulched fields is faster than the CHECK, and the NEW has the fastest change trend. The data suggest that fields mulched with gravel retain more water, with the NEW having the most noticeable water retention effect. The study’s findings can be used to investigate the regional variations in soil hydrodynamic characteristics in gravel mulched fields in arid locations.

The spatiotemporal variation of the model parameters of the soil-water characteristic curve (SWCC) reflect the soil water holding capacity and soil pore distribution state. It is an integral part of interdisciplinary disciplines such as soil hydrodynamics and ecohydrology. The authors selected the optimal SWCC model for the Lanzhou collapsible loess, used classical statistics and geostatistics methods to study the spatiotemporal variability of the SWCC model parameters, and using the comprehensive comparison of the mean relative differences (MRD), standard deviations (SDRD) and an index of temporal stability (ITS) determined the representativeness measuring point. The results showed that the SWCC parameter α was medium variability in the 0–30 cm soil layer, n and θs were of low variability, and the spatial distribution of the parameters of different soil layers was consistent. Migration direction prediction of θs was very similar in each layer, α, n and θs were all strongly significantly correlated positively. Moreover, the determination coefficient of representative measuring point 16 had the highest prediction accuracy for the measured values of SWCC. The results of this paper can be used as a simple method to predict SWCC and provide theoretical guidance for soil water management and soil collapse erosion monitoring in the collapsible loess area.

Gravel mulching is an ancient mulching system with a history of more than 300 years in China. To explore the changes of soil-water content (SWC) and heat transport in watermelon gravel-mulched fields under drip irrigation, we simulated three irrigation quotas (W1, 180 m3/hm2; W2, 270 m3/hm2; and W3, 360 m3/hm2) and three irrigation frequencies (F1, three times; F2, six times; and F3, nine times) based on HYDRUS-2D. The results indicated that peak SWC increased with irrigation quota. The range of fluctuation of SWC decreased as irrigation frequency increased. The temperature of the 0–40 cm soil layer varied with air temperature, but the range of fluctuation decreased with depth. Irrigation affected the distribution of soil water, increased soil heat capacity, and reduced the impact of air temperature on soil temperature, thus delaying the impact of air temperature on soil temperature. High-frequency drip irrigation could therefore effectively improve SWC, reduce water stress during the period of watermelon growth, and effectively delay the effect of air temperature on soil temperature, providing a theoretical basis for developing reasonable irrigation strategies and regulating soil water and heat in gravel-mulched fields.

Rotavirus live-attenuated vaccines, both mono- and pentavalent, generate broadly heterotypic protection. B-cells isolated from adults encode neutralizing antibodies, some with affinity for VP5*, that afford broad protection in mice. We have mapped the epitope of one such antibody by determining the high-resolution cryo-EM structure of its antigen-binding fragment (Fab) bound to the virion of a candidate vaccine strain, CDC-9. The Fab contacts both the distal end of a VP5* β-barrel domain and the two VP8* lectin-like domains at the tip of a projecting spike. Its interactions with VP8* do not impinge on the likely receptor-binding site, suggesting that the mechanism of neutralization is at a step subsequent to initial attachment. We also examined structures of CDC-9 virions from two different stages of serial passaging. Nearly all the VP4 (cleaved to VP8*/VP5*) spikes on particles from the earlier passage (wild-type isolate) had transitioned from the “upright” conformation present on fully infectious virions to the “reversed” conformation that is probably the end state of membrane insertion, unable to mediate penetration, consistent with the very low in vitro infectivity of the wild-type isolate. About half the VP4 spikes were upright on particles from the later passage, which had recovered substantial in vitro infectivity but had acquired an attenuated phenotype in neonatal rats. A mutation in VP4 that occurred during passaging appears to stabilize the interface at the apex of the spike and could account for the greater stability of the upright spikes on the late-passage, attenuated isolate. IMPORTANCE Rotavirus live-attenuated vaccines generate broadly heterotypic protection, and B-cells isolated from adults encode antibodies that are broadly protective in mice. Determining the structural and mechanistic basis of broad protection can contribute to understanding the current limitations of vaccine efficacy in developing countries. The structure of an attenuated human rotavirus isolate (CDC-9) bound with the Fab fragment of a broadly heterotypic protective antibody shows that protection is probably due to inhibition of the conformational transition in the viral spike protein (VP4) critical for viral penetration, rather than to inhibition of receptor binding. A comparison of structures of CDC-9 virus particles at two stages of serial passaging supports a proposed mechanism for initial steps in rotavirus membrane penetration.

Water shortages and soil salinization in arid regions of northwestern China have become an important factor limiting agricultural production and affecting the living conditions of farmers. Using existing water resources and salinized land scientifically and efficiently is important for improving agricultural production. We studied the characteristics of the infiltration and evaporation of soil water under the application of different amounts of biochar in indoor soil-column simulations with sand mulching to determine the effect of biochar on the infiltration and evaporation of soil water. We tested five treatments: sand mulching with no biochar (CK) and sand mulching with 0.5, 1.5, 2.5 and 4.5% biochar. Cumulative infiltration and the rate of migration of the wetting front were higher with 0.5 and 1.5% biochar and lower with 2.5 and 4.5% biochar than CK, respectively. The distance and duration of migration of the wetting front followed the power function F = a·tb, a relationship consistent with the Kostiakov model of infiltration. The cumulative evaporation of soil water was higher with 0.5 and 1.5% biochar and lower with 2.5 and 4.5% biochar than CK. The variation of cumulative evaporation was represented well by both the Black and Rose models of evaporation. The results of this study have important implications for the application of biochar in arid regions of northwestern China for improving the hydrological characteristics of soil in agricultural practices.

Evaporation from the soil is an important component of evapotranspiration, and mulching greatly affects soil evaporation. We conducted numerical simulations to study the effect of the thickness of sand mulch on soil evaporation. We tested nine treatments: mulching with sand thicknesses of 1, 3, 5, 6, 8, 10, 15 and 20 cm plus an unmulched control (CK). Accumulated evaporation was significantly lower, and the resistance to evaporation was significantly higher, for the mulched treatments than CK. The volumetric soil water content (SWC) was significantly higher for the mulched treatments than CK, but SWC varied little for thicknesses >5 cm. Heating was slower and more uniform for the mulched treatments than for CK. With the increase of the thickness of sand, the temperature transmission was slowed down. The change of soil temperature was not obvious at thicknesses >15 cm. A thickness of 5 cm was the most effective for storing water and preserving heat. Our results provide a theoretical basis and technical guidance for the effective use and management of soil water in farmland in arid regions.

Characterization of the variability of soil moisture, salt content and organic matter content (SOM) is of great significance in agricultural production management and sustainable soil utilization. We present a case study of the variability and modelling with the depth of soil moisture, salt and SOM in a gravelsand mulched jujube orchard, using Geostatistics and Kriging interpolation. Soil moisture, salt and SOM were measured in 256 samples collected from a gravel-sand mulched jujube orchard in the 0-10, 10-20, 20-30 and 30-50 cm. Soil moisture, salt and SOM were more variable in the surface soil, due to several environmental factors, the coefficients of variation (CV) of soil were lower than 23%, indicating weak to moderate variation. The coefficient of variation of moisture and organic matter decreased with the depth and the salinity increased with the depth. There is a significant correlation between each soil layer, which decreases with the increase of the soil layer. The accuracy of the function model with depth as an independent variable and soil properties as a dependent variable is higher than 0.88. To master the relationship among soil depth, salinity, soil moisture and organic matter content can provide theoretical value for agricultural comprehensive management.

Gasification for hydrogen production by the H-type finned tube embedded in the packed bed is considered to be more economical. Based on the thermal flow reversal reactor, the heat transfer characteristics of H-type finned tube embedded on the both sides of high-temperature zone of the packed bed under the quasi-steady were researched. The contribution of radiation heat transfer rate on the H-type finned tube is about 60.5% at most and radiation mainly occurs on the central tube. Within the range of inlet temperature and Re, the fin-assisted degree is both decreased gradually and the maximum is 48.9%. When the temperature is above 906 K or within the range of Re, the heat transfer rate of the fin is mainly from the radiation heat transfer rate. Under the condition of high inlet temperature and high Re, the fin-assisted degree is minimum, which indicates the operation stability of the H-type finned tube is better.

Mitochondria, chloroplasts and Gram-negative bacteria are encased in a double layer of membranes. The outer membrane contains proteins with a β-barrel structure1,2. β-Barrels are sheets of β-strands wrapped into a cylinder, in which the first strand is hydrogen-bonded to the final strand. Conserved multi-subunit molecular machines fold and insert these proteins into the outer membrane3-5. One subunit of the machines is itself a β-barrel protein that has a central role in folding other β-barrels. In Gram-negative bacteria, the β-barrel assembly machine (BAM) consists of the β-barrel protein BamA, and four lipoproteins5-8. To understand how the BAM complex accelerates folding without using exogenous energy (for example, ATP)9, we trapped folding intermediates on this machine. Here we report the structure of the BAM complex of Escherichia coli folding BamA itself. The BamA catalyst forms an asymmetric hybrid β-barrel with the BamA substrate. The N-terminal edge of the BamA catalyst has an antiparallel hydrogen-bonded interface with the C-terminal edge of the BamA substrate, consistent with previous crosslinking studies10-12; the other edges of the BamA catalyst and substrate are close to each other, but curl inward and do not pair. Six hydrogen bonds in a membrane environment make the interface between the two proteins very stable. This stability allows folding, but creates a high kinetic barrier to substrate release after folding has finished. Features at each end of the substrate overcome this barrier and promote release by stepwise exchange of hydrogen bonds. This mechanism of substrate-assisted product release explains how the BAM complex can stably associate with the substrate during folding and then turn over rapidly when folding is complete.

A new fiber cocktail reinforced cement–based materials (NFCRCM) with steel, polyvinyl alcohol (PVA) fiber, and calcium carbonate whisker (CCW) was developed to obtain powerful fire resistan...

The purpose of this study was to evaluate the effects of monovalent and divalent cations on the stability of a fat emulsion (Lipovenoes MCT) in total nutrient admixtures (TNAs) by testing the percentage of fat residing in globules5 µm (PFAT5) values.TNAs with different combinations of glucose (5% and 10%), amino acids (3.35 and 4.5 g/100 mL), Na+/K+ (100/39 mmol/L), Mg2+ (3.4 and 2.7 mmol/L), and fat emulsion (2.4%) were tested in triplicate at room temperature. The pH, mean droplet size (MDS), and PFAT5 were assessed at 0, 6, 12, 24, 36, and 48 h.In all seven groups, the TNA globule distribution was uniform, the pH value fluctuated in the range of 5.93-6.06, and the MDS met the limit of the United States Pharmacopeia (USP) within 48 h. The PFAT5 value of the control group 0 without electrolytes was the lowest; group 1 added monovalent ions of 139 mmol/L was significantly higher (P0.05) but without exceed the USP limit after 48 h. Groups 2 and 3 added Mg2+ 3.4 and 2.7 mmol/L respectively, based on group 1. Group 4 increased the amino acid concentration from 3.35% to 4.5% based on group 2, and group 5 reduced the glucose concentration from 10% to 5% based on group 4. Group 6 removed monovalent ions and retained only Mg2+ based on group 5. The PFAT5 values of group 2, 3, 4, and 5 exceeded the limit after 6 h and group 6 after 12 h. There was no statistical difference between group 2 and 4 (P0.05) or between group 4 and 5 (P0.05).When the concentration of glucose is 10-25% and the amino acid is 2.5-4.5%, The addition of monovalent ions affects the stability of fat emulsion in TNAs, however when the concentrations of Na+ ≤100 mmol/L and K+ ≤39 mmol/L, the PFAT5 value will not exceed the USP limit within 24 h. Mg2+ has a significant effect, the PFAT5 value will exceed the USP limit after 6 h when the concentration ≥2.7 mmol/L, which may cause potential safety hazards.

To evaluate the role of radiomics based on Chest Computed Tomography (CT) in the identification and severity staging of chronic obstructive pulmonary disease (COPD).This retrospective analysis included 322 participants (249 COPD patients and 73 control subjects). In total, 1395 chest CT-based radiomics features were extracted from each participant's CT images. Three feature selection methods, including variance threshold, Select K Best method, and least absolute shrinkage and selection operator (LASSO), and two classification methods, including support vector machine (SVM) and logistic regression (LR), were used as identification and severity classification of COPD. Performance was compared by AUC, accuracy, sensitivity, specificity, precision, and F1-score.38 and 10 features were selected to construct radiomics models to detect and stage COPD, respectively. For COPD identification, SVM classifier achieved AUCs of 0.992 and 0.970, while LR classifier achieved AUCs of 0.993 and 0.972 in the training set and test set, respectively. For the severity staging of COPD, the mentioned two machine learning classifiers can better differentiate less severity (GOLD1 + GOLD2) group from greater severity (GOLD3 + GOLD4) group. The AUCs of SVM and LR is 0.907 and 0.903 in the training set, and that of 0.799 and 0.797 in the test set.The present study showed that the novel radiomics approach based on chest CT images that can be used for COPD identification and severity classification, and the constructed radiomics model demonstrated acceptable performance.

Briefly review the recent structural work of transient receptor potential canonical (TRPC) ion channels by using electron cryo-microscopy (cryo-EM). The high resolution structures of TRPC3, TRPC4, TRPC5 and TRPC6 are discussed.

An effective evaluation of soil fertility can provide a theoretical basis for managing quality and strategies of fertilization for soil. Based on 32 m × 32 m grid sampling, the soil organic matter, total N, total P, total K, available K, available P, salinity and soil pH were used as the soil fertility evaluation factors. And we integrated evaluation of the soil fertility using classical statistics, geostatistics and modified Nemoro fertility index. The result shows that the mean value of pH was 8.89 which showed alkalinity. The CV for organic matter, total N, total K, pH and available K were low variation. Others (total P, available P and salinity) were moderate variation. The nugget variances for organic matter and total were strong spatial autocorrelation. Others were between 0.418 and 0.5, indicating moderate spatial autocorrelation. The spatial distribution of each fertility index was not obvious. The Ps was within the range of 0.63–0.80, all fertility indicators surrounding graphics areas were small in Radar map, indicating the fertility level was classified as barren. The mean fertility index, Pi, of the soil was in the order: available K > salinity > total K > available P > pH > total P > organic matter > total N. The soil organic matter and total N were the main limiting factors restraining soil fertility. The spatial distribution patterns of soil index and Ps were complicated and had no regularity with patch distribution at field scale. The methods of increasing organic fertilizers, crop rotation and fallow were practicable and necessary for soil fertilizing management, increasing yields and improving crop quality.

The Interconnected River System Network (IRSN) plays a crucial role in water resource allocation, water ecological restoration and water quality improvement. It has become a key part of the urban lake management. An evaluation methodology system for IRSN project can provide important guidance for the selection of different water diversion schemes. However, few if any comprehensive evaluation systems have been developed to evaluate the hydrodynamics and water quality of connected lakes. This study developed a comprehensive evaluation system based on multi-indexes including aspects of water hydrodynamics, water quality and socioeconomics. A two-dimensional (2-D) mathematical hydrodynamics and water quality model was built, using NH3-N, TN and TP as water quality index. The IRSN project in Tangxun Lake group was used as a testbed here, and five water diversion schemes were simulated and evaluated. Results showed that the IRSN project can improve the water fluidity and the water quality obviously after a short time of water diversion, while the improvement rates decreased gradually as the water diversion went on. Among these five schemes, Scheme V showed the most noticeable improvement in hydrodynamics and water quality, and brought the most economic benefits. This comprehensive evaluation method can provide useful reference for the implementation of other similar IRSN projects.

With the steam obtained by the energy released from ventilation air methane oxidation, the hydrogen production through gasification method is considered more commercial. In order to constrain the steam parameter fluctuation, the shunt honeycomb ceramics are adopted to fill between the heat exchange tubes. However, transient heat transfer characteristics of this kind of heat exchanger have not been fully studied. This paper carried out a numerical simulation study on the transient heat transfer characteristics of H finned tube under periodic reverse-flow conditions. Results show that the existence of shunt honeycomb ceramics enhances the effect of radiation. Gas flow direction reversing destructs the original boundary layer, achieving a sudden rise of the convective heat flux in the new upstream. It takes about 12s to form a new relative stable boundary layer. The apparent heat transfer coefficient achieves a maximum of 108.77 W m−2 K−1 and an average of 99.1 W m−2 K−1.

Chronic obstructive pulmonary disease (COPD) is a common disease with high morbidity and mortality, where early detection benefits the population. However, the early diagnosis rate of COPD is low due to the absence or slight early symptoms. In this paper, a novel method based on graph convolution network (GCN) for early detection of COPD is proposed, which uses small and weakly labeled chest computed tomography image data from the publicly available Danish Lung Cancer Screening Trial database. The key idea is to construct a graph using regions of interest randomly selected from the segmented lung parenchyma and then input it into the GCN model for COPD detection. In this way, the model can not only extract the feature information of each region of interest but also the topological structure information between regions of interest, that is, graph structure information. The proposed GCN model achieves an acceptable performance with an accuracy of 0.77 and an area under a curve of 0.81, which is higher than the previous studies on the same dataset. GCN model also outperforms several state-of-the-art methods trained at the same time. As far as we know, it is also the first time using the GCN model on this dataset for COPD detection.

In agricultural ecosystems, soil organic matter (SOM) is a major determinant and indicator of soil fertility and quality. The objectives of this study were to understand the spatial distribution of SOM and the accuracy of two interpolation methods evaluated: Kriging and inverse distance weighting (IDW) in a gravel-sand mulch of northwest China. We are measuring SOM in 256 soil samples collected from 0 to 10, 10–20, 20–30, and 30–50 cm layers at five sampling scales, 32 × 32, 28 × 28, 24 × 24, 20 × 20, and 16 × 16 m, and three sampling spacings, 4, 8, and 12 m. SOM content decreased with depth in each scale, varying from 2.41 to 5.75 g/kg. The SOM was weakly to moderately variable and has a strong spatial autocorrelation. The standard deviation was small for each soil layer, and the variability was low or weakly moderate, indicating that two interpolation methods were applicable to the entire data set. Kriging interpolation was more accurate than IDW. The distribution of SOM differed in the surface layers at the five sampling scales, which was more uniform as the sampling scale decreased. Eight meter is a reasonable sampling spacing. Through the scales effect and spacing change on SOM for fixed-point monitoring, combing the estimate of SOM to reduce the sampling workload will aid the supply of SOM in gravel-sand mulched fields in arid regions.

Concretes at different saturation degrees are needed to be prepared in the laboratory when studying the effects of humidity on its mechanical properties. Different humidity control methods ...

On a microscopic scale, concrete was regarded as a three-phase composite consisting of coarse aggregate, cement mortar and interface transition zone (ITZ). The coarse aggregates and their peripheral ITZ were equated with equivalent particles blended in cement mortar through two equivalent processes. Taking the effects of ITZ, aggregate gradation, maximum aggregate size and the interactions among equivalent particles into consideration, the average stress of microscopic phase of concrete was calculated based on a micromechanics model, and the stress concentration within ITZ phase was further solved. Adopting the Drucker-Prager criterion to decide the failure of the microscopic phases, the cracking strength, yield strength and ultimate strength of the concrete were calculated respectively when the ITZ cracking, the ITZ failure and the mortar failure occurred. The results were compared with test data to verify the effectiveness and reliability of the model. Based on the model, the influence of the elastic modulus of coarse aggregate, the coarse aggregate content and the elastic modulus of ITZ on the yield strength and ultimate strength are discussed. This paper presents an approach to explore the connection between macroscopic strength and microscopic phase strength, which provides a theoretical reference for studying the failure mechanism of concrete.

Signals arising from bacterial infections are detected by pathogen recognition receptors (PRRs) and are transduced by specialized adapter proteins in mammalian cells. The Receptor-interacting-serine/threonine-protein kinase 2 (RIPK2 or RIP2) is such an adapter protein that is critical for signal propagation of the Nucleotide-binding-oligomerization-domain-containing proteins 1/2 (NOD1 and NOD2). Dysregulation of this signaling pathway leads to defects in bacterial detection and in some cases autoimmune diseases. Here, we show that the Caspase-activation-and-recruitment-domain (CARD) of RIP2 (RIP2-CARD) forms oligomeric structures upon stimulation by either NOD1-CARD or NOD2-2CARD. We reconstitute this complex, termed the RIPosome in vitro and solve the cryo-EM filament structure of the active RIP2-CARD complex at 4.1 Å resolution. The structure suggests potential mechanisms by which CARD domains from NOD1 and NOD2 initiate the oligomerization process of RIP2-CARD. Together with structure guided mutagenesis experiments at the CARD-CARD interfaces, we demonstrate molecular mechanisms how RIP2 is activated and self-propagating such signal., The pathogen recognition receptors NOD1/2 recognize bacterial cell wall components and signal through their downstream adapter kinase RIP2 via a CARD (Caspase activation and recruitment domain) mediated oligomerization process. Here the authors present the cryo-EM structure of the active RIP2-CARD filament and discuss implications for NOD1/2-RIP2 signalling.