Search

In this work, the influence of Si concentration on the microstructure and growth of plasma electrolytic oxidation (PEO) coatings on two types of Al–Si–Mg aluminum alloys were investigated. we utilized a multiscale correlative methodology to analyze the microstructure and micro-defect characteristics of the PEO coatings formed on A357 and 6082 aluminum alloys. The results demonstrate that both coatings exhibit a porous structure and are primarily composed of alumina and amorphous phases. Notably, the PEO coating formed on A357 alloy exhibits lower thickness, higher porosity, and more non-uniform barrier layer compared to that on 6082 alloy due to a higher concentration of Si in the substrate. Advanced X-ray computed tomography effectively characterizes micro-defects with different morphologies within the two coatings. Through microstructural observation and micro-defect characterization, we elucidate the influence of Si on the coating growth. [ABSTRACT FROM AUTHOR]

• Anodic oxidation coating's cracking causes a severe substrate stress concentration. • Sealing weakens anodic oxidation coating's cracking resistance during fatigue tests. • Prior shot peening enhances the fatigue property of anodic oxidation coated specimen. In this study, the effects of sealing and prior shot peening treatments on the fatigue behavior of the sulphuric acid anodic oxidation coated 6082-T6 aluminium alloy were investigated. Experimental results indicate that the preferential fracture of anodic oxidation coatings due to its higher brittleness and lower fracture toughness as well as the stress concentration of near-interface substrate caused by the interface cyclic dislocation accumulation could cause the fatigue failure of anodic oxidation coated specimens. Consequently, the fatigue property of anodic oxidation coated specimens notably decreases compared to as-machined specimens, with a decrease of 26.7 % in the fatigue limit corresponding to 2 × 107 fatigue cycles. Additionally, the sealing treatment introduces numerous cracks that penetrate the coating entirely, diminishing the coating's resistance to cracking under fatigue loading; this alteration changes the fatigue failure mechanism of anodic oxidation coated specimens, ultimately resulting in a decrease of 15.5 % in the fatigue limit of anodic oxidation coated specimens. Despite exacerbating the surface integrity and increasing the surface roughness of anodic oxidation coated specimens, the prior shot peening treatment increases the fatigue limit of anodic oxidation coated specimens by 82.8 % since the affecting layer beneath the interface plays a crucial role in inhibiting the further propagation of coating cracks into the substrate as well as the crack propagation in the substrate beneath the interface. [ABSTRACT FROM AUTHOR]

• The UPM and PI iterative methods can accurately reconstruct the residual stress field induced by rolling processing. • The extended finite element method and the weight function method are applied to solve the stress intensity factor. • The necessity of deep rolling treatment for axles is verified. • The influence of interference and initial crack position on the remaining life of axle is explored. • The damage tolerance analysis of the axle was carried out. Deep rolling surface strengthening is an effective way to introduce compressive residual stress (CRS) along the railway axle, which can improve the fatigue resistance of the material. The CRS field was rebuilt adopting the proportional-integral (PI) iteration method and the unit pressure method (UPM) to study the fatigue cracking behavior of deep-rolled EA4T railway axles. The remaining life prediction model and the stress intensity factor (SIF) solution method were then validated using simulations and testing with small-sized specimens. The remaining life of the EA4T railway axle was then calculated by applying a realistic vertical load spectrum. The results showed that CRS prevented crack propagation, enhanced the critical propagation size of railway axle cracks, and prolonged the remaining life of the axle. Additionally, the remaining life of the axle may not support the following maintenance period if a crack with an extendable size emerges at the unloading groove of the railway axle. This work provides a theoretical basis for the optimization of the non-destructive testing (NDT) interval of deep-rolled EA4T railway axles. [ABSTRACT FROM AUTHOR]

• Prior shot peening improves the CF limit of AO coated aluminum alloy by 50 %. • AO specimens exhibit different CF failure modes under low and high applied stress. • Substrate residual stress and microstructure affect the CF crack propagating path. • Substrate residual stress relaxes in distinct mode under low and high applied stress. Plain (anodic oxidation) and composite (prior shot peening + anodic oxidation) coatings were prepared to investigate their effects on the corrosion-fatigue (CF) property of 6082-T6 aluminium alloy in a 3.5 wt% NaCl aqueous solution. The results indicate that plain coated specimens exhibited similar CF properties to as-machined specimens at low applied stresses. However, under high applied stresses, the plain coating led to a preferential fracture and was unable to effectively prevent corrosion medium. Hence, the CF property of plain coated specimens was found to be inferior to as-machined specimens at high applied stresses. The synergetic effect of substrate residual stress and microstructure beneath the coating-substrate interface reduced the crack propagating rate in the initial stage by deflecting the crack at the grain boundary. Therefore, the CF property of composite coated specimens improved as a whole when compared with as-machined and plain coated specimens. Besides, under low applied stresses, the near-interface substrate residual stress of composite coated specimens occurred the relaxation due to the substrate crack propagation, while under high applied stresses, this was due to the synergetic effect of materials' local cyclic yield and plastic flow, as well as the substrate crack propagation. [ABSTRACT FROM AUTHOR]

• The surface properties of EA4T axle steel treated by ultrasonic surface rolling process (USRP) are investigated. • Effect of USRP on the electrochemical corrosion resistance and corrosion fatigue performance is elucidated. • Residual stress relaxation mechanism of USRP-treated EA4T axle steel in air and corrosion is revealed. • Influence of residual stress relaxation on the corrosion fatigue resistance is clarified. The fatigue properties and residual stress relaxation behavior of EA4T axle steel treated by ultrasonic surface rolling process (USRP) are investigated in air and corrosive environments. The result reveals that the surface roughness (Ra) is decreased from 1.42 to 0.17 μm after the USRP. A surface layer with ultrafine grains, work hardening, and compressive residual stress (CRS) is achieved by the USRP. Compared with the as-machined specimens, the USRP specimens exhibit slightly lower electrochemical corrosion resistance but superior fatigue performance in air and corrosive environments. The dislocation density is significantly decreased in the corrosive environment during fatigue loads, accompanied by a rapid relaxation of surface CRS. The influence of USRP on the corrosion fatigue performance is elucidated. The residual stress relaxation mechanism and its influence on fatigue resistance are also analyzed. [ABSTRACT FROM AUTHOR]

This work reports micro-defects and growth mechanism of the plasma electrolytic oxidation (PEO) coating formed on the surface of 6082-T6 aluminum alloy. Scanning electron microscopy (SEM), X-ray diffraction (XRD), transmission electron microscopy (TEM), and X-ray computed tomography techniques were used to characterize the morphology, phase, microstructure, and porosity of the PEO coating, respectively. The results confirmed a porous outer layer and a dense inner layer in the coating. The PEO coating was composed of γ- and α-Al 2 O 3 phases, and amorphous phases. A layer with only amorphous structures was found near the coating/substrate (C/S) interface, which could be ascribed to the high concentration of P element in the electrolyte. Micro-defects with different sizes and shapes inside the coating were successfully characterized by the high-resolution X-ray computed tomography technique, and the volume reconstruction result revealed a porosity fraction of 5.43% for the coating. A growth model was complemented to explain the growth mechanism and interconnected micro-defects of the PEO coating. • Micro-defects in the plasma electrolytic oxidation (PEO) coating formed on 6082-T6 alloy were firstly characterized by high-resolution X-ray computed tomography technique. • Formation of the amorphous structure at the coating/substrate (C/S) interface was highly dependent on P element in the electrolyte. • Growth mechanism of the coating was clarified based on the microstructural observation and micro-defect characterization. [ABSTRACT FROM AUTHOR]

Low, medium and high-intensity (0.19, 0.26 and 0.34 mmA) shot peening treatments and 0.34 mmA high-intensity shot peening combined with slight and severe polishing treatments were used as the pre-treatments to improve the fatigue property of micro-arc oxidation (MAO) coated 6082-T6 aluminum alloy, respectively. In consideration of the significance of substrate residual stress beneath the coating-substrate interface on MAO coated specimens' fatigue property, the substrate residual stress of various coated specimens was analyzed by the X-ray's powerful penetrability. Results indicate that the substrate residual stress state of MAO coated specimens is changed from tensile (+93 MPa) to compressive (−65 to −93 MPa) by the above pre-treatments, which is beneficial for inhibiting the crack initiation at the substrate or resisting the crack's further propagation from the coating into the substrate. Whereas, similar to the compressive residual stress induced by shot peening, the compressive substrate residual stress for prior shot peening + MAO composite coated specimens will also relax during the fatigue tests. In addition, the gradient compressive residual stress beneath the interface induced by prior shot peening reduce the crack propagating rate, thus improving the fatigue property of coated specimens; after the 0.26 mmA shot peening pre-treatment, the fatigue strength at 2 × 107 cycles of MAO coated specimens increases by 59.1 %. Finally, the effects of surface and interface roughness, substrate residual stress and in-depth compressive residual stress on the fatigue life of MAO coated specimens are further discussed. • Pre-treatments improve MAO coated Al alloys' fatigue life by 2.41 to 4.35 times. • Grain refinement of substrate increases MAO coatings' pore size and thickness. • Compressive substrate residual stress inhibits crack propagation beneath interface. • Compressive substrate residual stress relaxes by 8 % to 41 % at 104 fatigue cycles. [ABSTRACT FROM AUTHOR]

• CSP and MSP are used to improve the fatigue property of bare and MAO coated Al. • CSP and MSP introduce a grain-refined and CRS affected layer on surface. • CSP and MSP is more appropriate for MAO coated and bare Al, respectively. • Crack initiation stage dominates the fatigue property of bare Al. • Crack propagation stage dominates the fatigue property of MAO coated Al. Conventional shot peening (CSP) and micro-shot peening (MSP) are used to enhance the fatigue property of bare and micro-arc oxidation (MAO) coated 6082-T6 aluminum. The difference in the anti-fatigue strengthening mechanism of CSP and MSP on bare and MAO coated 6082-T6 aluminum alloy is revealed. Results show that MSP provides a more significant improvement in fatigue properties of bare specimens than CSP since the intensely inhibiting effect on crack initiation. Nevertheless, MAO coating impairs the surface integrity of MSP specimens, thus reducing the crack initiating life. In comparison, the effect of deeper affected layer induced by CSP on the improvement of crack propagating life is mostly retained after the MAO process. Hence, for the MAO coated specimen, the CSP prior-treatment is more effective in improving its fatigue property. [ABSTRACT FROM AUTHOR]

• Fatigue life prediction method of 25CrMo4 steel is investigated using fracture mechanics and machine learning methods. • Residual stress relaxation process is incorporated into fatigue crack growth in combination with NASGRO equation and equivalent initial flaw size (EIFS) methodology. • Different machine learning methods areemployed to investigate theireffectiveness in fatigue life prediction. In this work, fracture mechanics and machine learning methods are separately employed to predict the high cycle fatigue (HCF) life of micro-shot peened 25CrMo4 alloy steel containing artificial notches. The influences of notch size, stress level, and surface condition on fatigue life are incorporated into the prediction model. The results shows that the fatigue life of shot-peened specimens is enhanced by the compressive residual stress (CRS) compared with that of the un-peened specimens. The prediction result using fracture mechanics method is within the error band of ±2, while that using machine learning method almost lies in the error band of ±1.5. The stress level and notch size are the most critical factors affecting the HCF fatigue life. The applicability and limitation of the two methods are finally discussed. [ABSTRACT FROM AUTHOR]

The effects of micro-shot peening (MSP) and artificial surface defects were investigated in relation to the defect tolerance of Al-Si-0.6Mg alloy in the framework of fracture mechanics. The results indicated that coral-shaped casting defects inside the alloy could be effectively quantified using the X-ray synchrotron radiation technique. An affected layer with a surface roughness (Ra) of 1.25 and residual stress of − 125 MPa was introduced on the MSP specimen compared to the un-peened (UP) specimen. The fatigue strengths of the UP and MSP specimens containing the artificial defects decreased as the defect size increased under rotating bending fatigue tests, except in the case of defects with the equivalent size of 395 and 490 µm, respectively. MSP could shift the crack initiation site toward the subsurface, while all the cracks of the specimens with the artificial defects originated from the surface and maintained an aspect ratio of 0.66 during the crack growth process. The relationship between the defect sizes and the fatigue strengths could be reasonably assessed by the modified Kitagawa-Takahashi (K-T) diagrams. The critical defect size of the MSP specimens was increased from 450 to 542 µm compared with that of the UP specimens, owing to the beneficial effect of the compressive residual stress. The defect tolerance of the Al-Si-0.6Mg alloy was improved by the MSP process. • Effects of micro-shot peening (MSP) on the fatigue properties of Al-Si-0.6Mg alloy are explored. • Casting defect inside the alloy was identified using synchrotron radiation X-ray computed microtomography (SR-μCT) technique. • The influence of MSP on the fatigue tolerance was characterized by Kitagawa-Takahashi (K-T) diagrams. • The critical defect size harmless to fatigue strength was evaluated using fracture mechanics. [ABSTRACT FROM AUTHOR]

• Effects of the corrosive environment on the fatigue strength of EA4T axle steel are explored. • The evolution of corrosion process during fatigue loading is fully investigated. • Crack aspect ratio in the corrosive environment is obtained by using synchrotron radiation X-ray computed microtomography (SR-μCT). • Fatigue life prediction model is developed based on the pit growth, short crack growth, and long crack growth stages. High-speed railway axle is the critical safety component of modern ground vehicles, which experiences extremely complex environments. In this paper, the effect of corrosion on the fatigue behavior of EA4T axle steel was investigated in an artificial rainwater environment. Combining scanning electron microscopy (SEM) and synchrotron radiation X-ray micro computed microtomography (SR-μCT) with theoretical analysis, damage measurement enabled a full evolution characterization of the corrosion process for exploring the corrosion mechanism and its influence on the fatigue life. It is found that the corrosive environment significantly reduced fatigue strength and facilitated multiple crack initiation, while showed relatively little effect on the long fatigue crack growth. The fitness of the 3-P Weibull distribution was slightly higher than that of the Gumbel distribution in terms of crack population. The life prediction model incorporating the pit growth, short crack, and long crack stages showed a good agreement within the 95% and 5% probabilistic S-N curve. [ABSTRACT FROM AUTHOR]

• The extended finite element method is used in the fracture mechanics simulation of EA4T axle steel specimen and full-scale axle. • Numerical model is built considering residual stress and wheelset press-fitting. • The effectiveness of the extended finite element method (XFEM) was verified by comparing the simulation and experimental results. • The measured load spectrum was applied, and the NASGRO equation was used to calculate the residual life of the axle. High-speed railway axles may be damaged during service or maintenance. Therefore, to ensure axle service safety, the residual life of damaged axles is necessary for an accurate assessment. In this study, a small-sized specimen was analyzed and the effectiveness of the extended finite element method (XFEM) was verified by comparing the simulation and test results. Subsequently, the residual life of the EA4T axle with an initial crack was evaluated using the XFEM, which is based on fracture mechanics, and the actual axle service load spectrum. The results show that the critical failure sizes for the residual life of the power axle and non-power axle were 7 and 4 mm, respectively, for a crack located in the middle of the axle body; in contrast, for a crack located in the arc transition of the wheel seat, the critical failure dimensions were 9 and 5 mm, respectively. Based on the NASGRO equation and considering the damage tolerance safety factor, the residual lives of the power axle for the two crack locations were estimated to be 1.3953 × 106 and 9.636 × 105 km, respectively, while those of the non-power axle were 2.095 × 106 and 1.2583 × 106 km, respectively. The results of this study can provide a reference for the axle non-destructive testing (NDT) period. [ABSTRACT FROM AUTHOR]

In this paper, The combination of back-propagation neural network (BPNN) and genetic algorithm (GA) is used to optimize the current collection quality of the pantograph-catenary system. The contact force standard deviation (CFSD) between pantograph and catenary is utilized as the optimization index. The optimization works in this paper are as follows. 1. The equivalent mass, stiffness, and damping of the pantograph. 2. The distance between each dropper and the positioning point. 3. The length of each dropper. 4. The tension of contact wire, messenger wire, and stitch wire. Firstly, a pantograph-catenary coupling simulation model verified by EN 50318: 2018 and the line experiment result is established in this paper. Then, the pantograph-catenary coupling simulations are conducted according to the experiments designed by center composite design (CCD). The BPNN models accurately reflecting the relationship between the optimized input parameters and the output CFSD are established. Subsequently, the minimum CFSD of the BPNN model and the corresponding optimal parameter combinations are searched through GA. Finally, an evaluation method based on the BPNN weight matrix and the Garson equation is used to quantify the relative importance of the input optimized parameters of the established BPNN. [ABSTRACT FROM AUTHOR]

In recent years, the frequency and intensity of exposure to heat stress have increased gradually, seriously hampering the production of maize. This paper presents a study designed to analyze how the development, physiology and dispersal of pollen from the heat‐resistant maize variety Zhengdan958 and the heat‐sensitive maize variety Xianyu335 are affected by exposure to heat stress during the tasselling stage. Our results showed That exposure to heat stress significantly increased the antioxidant enzyme activity in pollen. Upon visual inspection of the pollen, we found that the lower water content had given rise to wrinkles in the pollen surface, sunken germination pores, and morphological deformations. In addition, the anther dehiscence process was hindered, resulting in a reduced amount of pollen being dispersed. We also found elevated levels of abscisic acid (ABA), jasmonic acid (JA) and its derivatives, indole acetic acid (IAA) and gibberellin‐3 (GA3) in heat‐pollens, as well as elevated ratios of IAA to ABA and ABA to GA3. Ultimately impaired pollen fertility. Summarizing, our experiment revealed that reduced pollen quantity and quality are significant contributors to fertility losses in summer maize exposed to heat stress at anthesis, and we hope that our analysis of the physiological mechanisms involved can contribute to the development of crop management measures aimed at countering the increasingly detrimental effects of heat stress on the production of summer maize. [ABSTRACT FROM AUTHOR]

The greenhouse effect caused by global warming was becoming more and more obvious, resulting in increased frequency of high temperature and high humidity, which significantly affected maize productivity. However, it was poorly understood how the interactions of high temperature and high humidity affected leaf senescence, photosynthetic performance and yield of summer maize. Three stress treatments including (a) high temperature stress (T), (b) waterlogging stress (W) and (c) complex stress (T‐W) were set at the third leaf stage (V3), the sixth leaf stage (V6) and the tasselling stage (VT) in 2019–2020 to explore the influence mechanism of complex stress. Each stress treatment period lasted 6 days. Non‐stressed plants served as control. Yield, antioxidant enzyme activity, photosynthetic characteristics, and dry matter accumulation were determined. Our study found that the activity of antioxidant enzymes was significantly decreased, while malonyldialdehyde (MDA) accumulation was increased under each stress treatment. As a result, the photosynthetic characteristics were impaired, manifested in a significant decrease in net photosynthetic rate (Pn), enzyme activities of phosphoenolpyruvate carboxylase (PEPCase) and ribulose diphosphate carboxylase (RUBPCase). The decrease in photosynthetic intensity affected by each stress treatment led to a significant decrease in total dry matter accumulation and grain yield. The most significant effects of waterlogging and combined stresses on yield occurred at the V3 stage, followed by the V6 and VT stages. However, the most significant effects of high temperature occurred at the VT stage, followed by the V6 and V3 stages. Moreover, the compound stress exacerbated damage to leaf senescence and photosynthetic properties of summer maize compared to the single stress of high temperature or waterlogging. [ABSTRACT FROM AUTHOR]

• Cause and consequence analysis for industrial hot work is conducted. • The ABT model and PN are integrated to analyze hot work accident evolution. • An improved regional center method is developed to obtain crisp evaluation value. • Data fitting is performed for probability calculation. Hot work poses great hazards to industrial operation site. Although regulatory and guidance exist, accidents caused by hot work continue to occur. Risk assessment has proved to be an effective method for risk control. However, current studies paid less attention to the evolution process of industrial hot work accidents and the quantitative risk assessment seems to be insufficient. In this context, we aimed to perform comprehensive risk evolution analysis and quantitative risk assessment of hot work using adaptive bow tie (ABT) and Petri nets (PNs). The ABT model is improved to analyze deep causes, consequences, and their relationships. PNs are employed to conduct quantitative risk assessment. To address uncertainties, the triangular membership function and improved regional center method are proposed to calculate the confidences of all places and transitions in the PNs. The probabilities are finally obtained by data fitting method. The study found that the most likely consequence of hot work accident is near miss. The results also indicate that hot work accident prevention measures should emphasize on the isolation of workplace, combustible gases test, removal of combustible substances, job organization, and job training. Besides, emergency devices maintenance and emergency drilling are critical to prevent accidents from expanding. [Display omitted] [ABSTRACT FROM AUTHOR]

It's well known that the development and distribution of roots could be regulated to obtain deep soil resource and enhance the grain yield by increasing the depth of fertilization, but little is known about whether increasing P fertilization depth can optimize the root distribution to delay leaf senescence, enhance photosynthetic performance and root-shoot coordination or not. We conducted a field experiment that tested the following four placement depths of P fertilization: 5 cm (P 5), 10 cm (P 10), 15 cm (P 15), and 20 cm (P 20). The experiment was designed to explore the regulatory effects of the P fertilization depth on the root growth and distribution, the photosynthetic performance, the root-shoot coordination, the yield formation, the N and P fertilizer utilization of maize plants. We found that deep P placement did indeed alter the root parameters. In the 20–60 cm soil layer, both the root dry weight and length of P 15 treatment were on average 23.2% higher than those of P 5 treatment. The specific root length and specific root surface area of P 15 treatment were 4.5% and 5.6% higher than those of P 5 treatment. In addition, the P 15 treatment achieved a significantly improved photosynthetic performance over the P 5 treatment: The leaf area index at the R6 stage was 10.2% higher, the leaf senescence index from the R2 to the R6 stages was 31.4% lower, the photosynthetic rate at the R3 stage was 25.9% higher. The P placement depth also optimized the root-shoot coordination: The ratios of root weight to shoot weight, root surface area to leaf area, and root length to leaf area of P 15 treatment were 6.7%, 13.8%, and 12.7% higher than those of P 5 treatment, respectively. Finally, the root P and N uptake efficiency, the photosynthetic P-use efficiency, and the physiological P-use efficiency of P 15 treatment were all significantly higher than those of P 5 treatments. And together these responses had the effect of increasing the mature biomass by 12.5%, and the grain yield by 22.0%. In conclusion, increasing the P fertilization placement depth to 15 cm regulates the growth and development of the root system, which in turn improves the capability of plant to uptake and utilize N and P in the soil, delays the onset of leaf senescence, enhances its photosynthetic performance and biomass accumulation rate, and thus ultimately increases the yield. [Display omitted] • Deep P fertilization optimizes root growth, and root-shoot coordination. • Deep P fertilization delays leaf senescence and improves photosynthetic performance. • Optimized root-shoot coordination improves the grain yield and nutrient use efficiency. [ABSTRACT FROM AUTHOR]

Global climate changes have led to frequent and recurrent heat stress, which has seriously affected the world maize production. The experiment presented in this paper was carried out during the maize‐growing season in 2021 and 2022 at the Huang–Huai–Hai Region Maize Science and Technology Innovation Center (36°09′N, 117°09′E) in Tai'an, Shandong province, China. The test site is located in the semi‐humid warm temperate continental monsoon climate zone, soil is brown loam. We selected different heat‐sensitive maize varieties: heat‐tolerant variety Zhengdan 958 (ZD958) and heat‐sensitive variety Xianyu335 (XY335) to study the stress effects of high temperature on the development of tassel in the key stage of its differentiation (the 12‐leaf stage, V12). We found that exposure to heat stress during the V12 stage significantly reduced the tassel size and the anther dehiscence area, making it difficult to disperse pollen, thus effectively reducing pollen production. In addition, heat stress had significant negative effects on pollen development, resulting in deformed pollen and lower pollen viability and germination rate. Our results also showed that heat stress significantly increased the activities of key reactive oxygen species‐scavenging enzymes including superoxide dismutase, peroxidase and catalase, and that the malondialdehyde and H2O2 content in tassels exposed to heat stress were significantly higher than those control group, where it should be noted that for the XY335, these effects were more pronounced than for the ZD958. The endogenous hormone content of tassels exhibited a variety of responses. After heat stress, the zeatin and salicylic acid content in tassels of both maize varieties were significantly lower than those in the respective control groups, while the abscisic acid and gibberellin acid content were significantly higher. With respect to the jasmonic acid and 3‐indoleacetic acid content, the two maize varieties exhibited opposite responses: in tassels from ZD958 plants subjected to heat stress were higher than those in the respective control group, while in tassels from XY335 plants, they were lower. The observed changes in protective enzyme activities and endogenous hormone contents induced by heat stress significantly affected the development of maize tassels and significantly reduced the amount, activity and germination rate of pollen. [ABSTRACT FROM AUTHOR]

Background: Acute lung injury is characterized by overwhelmingly elevated PAI-1 in both lung edema fluid and the circulating system. The role of increased PAI-1, encoded by Serpine1 gene, in the regeneration of injured lung epithelium has not been understood completely. This study aimed to investigate the role of Serpine1 in the regulation of alveolar type 2 epithelial cell (AT2) fate in a humanized mouse line carrying diseased mutants (Serpine1Tg). Methods: Wild-type (wt) and Serpine1Tg AT2 cells were either cultured as monolayers or 3D alveolospheres. Colony-forming assay and total surface area of organoids were analyzed. AT1 and AT2 cells in organoids were counted by immunohistochemistry and fluorescence-activated cell sorting (FACS). To test the potential effects of elevated PAI-1 on the permeability in the epithelial monolayers, we digitized the biophysical properties of polarized AT2 monolayers grown at the air–liquid interface. Results: A significant reduction in total AT2 cells harvested in Serpine1Tg mice was observed compared with wt controls. AT2 cells harvested from Serpine1Tg mice reduced significantly over the wt controls. Spheroids formed by Serpine1Tg AT2 cells were lesser than wt control. Similarly, the corresponding surface area, a readout of re-alveolarization of injured epithelium, was markedly reduced in Serpine1Tg organoids. FACS analysis revealed a significant suppression in the number of AT2 cells, in particular, the CD44+ subpopulation, in Serpine1Tg organoids. A lesser ratio of AT1:AT2 cells in Serpine1Tg organoids was observed compared with wt cultures. There was a significant increase in transepithelial resistance but not amiloride inhibition. Conclusions: Our study suggests elevated PAI-1 in injured lungs downregulates alveolar epithelial regeneration by reducing the AT2 self-renewal, particularly in the CD44+ cells. [ABSTRACT FROM AUTHOR]

Purpose: The developmental status of the male and female spike determines grain number (GN) per ear and yield. A better understanding of the effect of N on male and female spike differentiation and GN formation could help to gain insight into the mechanism of N regulation on yield. Methods: A field experiment was conducted with four nitrogen rates: 0 (N0), 129 (N1), 185 (N2), and 300 kg N ha−1 (N3) with a single summer maize hybrid to determine tassel and ear development and the resulting GN. Results: The expression of key proteins and genes related to fatty acid metabolism of N0 were down-regulated and the tapetum was abnormally degraded. This inhibited the synthesis of long-chain fatty acids (LCFAs) in the tassel and ear. Both pollen and silk development at the mononucleate stage were abnormal and presented as misshapen pollen, uneven silk tube, reduced silk, and poor pollination. Finally, anthesis-silking interval (ASI) was increased and the length of male and female spikes, fertilized florets, floret fertility percentage, and grain set rate were reduced in N0 treatment resulting in reduced GN. N application promoted fatty acid metabolism but N application greater than 185 kg N ha−1 did not increase LCFA of either male or female spike traits. Conclusions: A nitrogen rate of 185 kg N ha−1 was sufficient to promote lipid metabolism, and increase the content of LCFAs. This resulted in normal pollen and silk development, shortened ASI and led to an increase in the number of fertile florets, fertilization percentage, and GN. [ABSTRACT FROM AUTHOR]

In order to improve the brittle characteristics of coral cement-based composites and increase their toughness, an experimental study was carried out on the basic mechanical properties of PVA (polyvinyl alcohol) fiber-reinforced coral cement-based composites, taking into account the fiber content and length-to-diameter ratio (L/D). The results showed that PVA fibers can effectively improve the mechanical properties of concrete, especially its tensile strength. At the same time, PVA fibers improved the damage characteristics of cement-based composites and had obvious toughening and brittleness reduction effects. The PVA fibers, with a volume content of 1.5% and an L/D of 225, had the best performance in reinforcing the overall performance of the coral cement-based composites. Too many PVA fibers or a large length-to-diameter ratio would make it difficult for the fibers to contribute to toughness and cracking resistance and even cause defects in the matrix, reducing the mechanical properties. The tensile stress-strain curves of PVA fiber-reinforced coral cement-based composites were consistent with the trilinear constitutive model curves and showed the tensile characteristic of strain hardening after the occurrence of the main cracks. [ABSTRACT FROM AUTHOR]

Corn-peanut intercropping is an important element of China's agricultural planting model as it confers ecological benefits and increases yield. The aim of this study was to explore the productivity differences between intercropping and monoculture by using the 13C isotope tracer labelling method. Corn hybrid Denghai 618 (DH618) and peanut variety Huayu 22 (HY22) were used as test materials under three planting methods, single corn, SM; single peanut, SP; and corn-peanut intercropping, IM and IP, respectively, during two growing seasons. The results showed that IM increased yield by 59.7% and 62.3% compared with SM, respectively. IP reduced yield by 31.3% and 32.3% compared with SP, respectively. IM significantly increased the photosynthetic rate, leaf area, 13C assimilation distribution, and dry matter accumulation of summer corn, which led to an increase in the kernel number and grain yield. The decrease in intercropped peanut yield was mainly caused by a decrease in the full-pod rate and number of pods per plant. The decrease in peanut yield did not affect the production of intercropping benefit due to the larger intercropping advantage and land equivalence ratio. Corn-peanut intercropping yielded greater economic benefits than monoculture. These results showed the utility of the peanut-corn intercropping model. [ABSTRACT FROM AUTHOR]

Background: Soil salt stress is a problem in the world, which turns into one of the main limiting factors hindering maize production. Salinity significantly affects root physiological processes in maize plants. There are few studies, however, that analyses the response of maize to salt stress in terms of the development of root anatomy and respiration. Results: We found that the leaf relative water content, photosynthetic characteristics, and catalase activity exhibited a significantly decrease of salt stress treatments. However, salt stress treatments caused the superoxide dismutase activity, peroxidase activity, malondialdehyde content, Na+ uptake and translocation rate to be higher than that of control treatments. The detrimental effect of salt stress on YY7 variety was more pronounced than that of JNY658. Under salt stress, the number of root cortical aerenchyma in salt-tolerant JNY658 plants was significantly higher than that of control, as well as a larger cortical cell size and a lower root cortical cell file number, all of which help to maintain higher biomass. The total respiration rate of two varieties exposed to salt stress was lower than that of control treatment, while the alternate oxidative respiration rate was higher, and the root response of JNY658 plants was significant. Under salt stress, the roots net Na+ and K+ efflux rates of two varieties were higher than those of the control treatment, where the strength of net Na+ efflux rate from the roots of JNY658 plants and the net K+ efflux rate from roots of YY7 plants was remarkable. The increase in efflux rates reduced the Na+ toxicity of the root and helped to maintain its ion balance. Conclusion: These results demonstrated that salt-tolerant maize varieties incur a relatively low metabolic cost required to establish a higher root cortical aerenchyma, larger cortical cell size and lower root cortical cell file number, significantly reduced the total respiration rate, and that it also increased the alternate oxidative respiration rate, thereby counteracting the detrimental effect of oxidative damage on root respiration of root growth. In addition, Na+ uptake on the root surface decreased, the translocation of Na+ to the rest of the plant was constrained and the level of Na+ accumulation in leaves significantly reduced under salt stress, thus preempting salt-stress induced impediments to the formation of shoot biomass. [ABSTRACT FROM AUTHOR]

The family of ten-eleven translocation dioxygenases (TETs) consists of TET1, TET2, and TET3. Although all TETs are expressed in hematopoietic tissues, only TET2 is commonly found to be mutated in age-related clonal hematopoiesis and hematopoietic malignancies. TET2 mutation causes abnormal epigenetic landscape changes and results in multiple stages of lineage commitment/differentiation defects as well as genetic instability in hematopoietic stem/progenitor cells (HSPCs). TET2 mutations are founder mutations (first hits) in approximately 40–50% of cases of TET2-mutant (TET2MT) hematopoietic malignancies and are later hits in the remaining cases. In both situations, TET2MT collaborates with co-occurring mutations to promote malignant transformation. In TET2MT tumor cells, TET1 and TET3 partially compensate for TET2 activity and contribute to the pathogenesis of TET2MT hematopoietic malignancies. Here we summarize the most recent research on TETs in regulating of both normal and pathogenic hematopoiesis. We review the concomitant mutations and aberrant signals in TET2MT malignancies. We also discuss the molecular mechanisms by which concomitant mutations and aberrant signals determine lineage commitment in HSPCs and the identity of hematopoietic malignancies. Finally, we discuss potential strategies to treat TET2MT hematopoietic malignancies, including reverting the methylation state of TET2 target genes and targeting the concomitant mutations and aberrant signals. [ABSTRACT FROM AUTHOR]

Introduction: Splice modulators have been assessed clinically in treating haematologic malignancies exhibiting splice factor mutations and acute myeloid leukaemia. However, the mechanisms by which such modulators repress leukaemia remain to be elucidated.Objectives: The primary goal of this assessment was to assess the molecular mechanism by which the natural splice modulator GEX1A kills leukaemic cells in vitro and within in vivo mouse models.Methods: Using human leukaemic cell lines, we assessed the overall sensitivity these cells have to GEX1A via EC50 analysis. We subsequently analysed its effects using in vivo xenograft mouse models and examined whether cell sensitivities were correlated to genetic characteristics or protein expression levels. We also utilised RT-PCR and RNAseq analyses to determine splice change and RNA expression level differences between sensitive and resistant leukaemic cell lines.Results: We found that, in vitro, GEX1A induced an MCL-1 isoform shift to pro-apoptotic MCL-1S in all leukaemic cell types, though sensitivity to GEX1A-induced apoptosis was negatively associated with BCL-xL expression. In BCL-2-expressing leukaemic cells, GEX1A induced BCL-2-dependent apoptosis by converting pro-survival BCL-2 into a cell killer. Thus, GEX1A + selective BCL-xL inhibition induced synergism in killing leukaemic cells, while GEX1A + BCL-2 inhibition showed antagonism in BCL-2-expressing leukaemic cells. In addition, GEX1A sensitised FLT3-ITD+ leukaemic cells to apoptosis by inducing aberrant splicing and repressing the expression of FLT3-ITD. Consistently, in in vivo xenografts, GEX1A killed the bulk of leukaemic cells via apoptosis when combined with BCL-xL inhibition. Furthermore, GEX1A repressed leukaemia development by targeting leukaemia stem cells through inhibiting FASTK mitochondrial isoform expression across sensitive and non-sensitive leukaemia types.Conclusion: Our study suggests that GEX1A is a potent anti-leukaemic agent in combination with BCL-xL inhibitors, which targets leukaemic blasts and leukaemia stem cells through distinct mechanisms. [ABSTRACT FROM AUTHOR]

The ten–eleven translocation (TET) family of dioxygenases consists of three members, TET1, TET2, and TET3. All three TET enzymes have Fe+2 and α-ketoglutarate (α-KG)-dependent dioxygenase activities, catalyzing the 1st step of DNA demethylation by converting 5-methylcytosine (5mC) to 5-hydroxymethylcytosine (5hmC), and further oxidize 5hmC to 5-formylcytosine (5fC) and 5-carboxylcytosine (5caC). Gene knockout studies demonstrated that all three TET proteins are involved in the regulation of fetal organ generation during embryonic development and normal tissue generation postnatally. TET proteins play such roles by regulating the expression of key differentiation and fate-determining genes via (1) enzymatic activity-dependent DNA methylation of the promoters and enhancers of target genes; and (2) enzymatic activity-independent regulation of histone modification. Interacting partner proteins and post-translational regulatory mechanisms regulate the activities of TET proteins. Mutations and dysregulation of TET proteins are involved in the pathogenesis of human diseases, specifically cancers. Here, we summarize the research on the interaction partners and post-translational modifications of TET proteins. We also discuss the molecular mechanisms by which these partner proteins and modifications regulate TET functioning and target gene expression. Such information will help in the design of medications useful for targeted therapy of TET-mutant-related diseases. [ABSTRACT FROM AUTHOR]

Our understanding of MM genomics has expanded rapidly in the past 5–10 years as a consequence of cytogenetic analyses obtained in routine clinical practice as well as the ability to perform whole-exome/genome sequencing and gene expression profiling on large patient data sets. This knowledge has offered new insights into disease biology and is increasingly defining high-risk genomic patterns. In this manuscript, we present a thorough review of our current knowledge of MM genomics. The epidemiology and biology of chromosomal abnormalities including both copy number abnormalities and chromosomal translocation are described in full with a focus on those most clinically impactful such as 1q amplification and del(17p) as well as certain chromosome 14 translocations. A review of our ever-expanding knowledge of genetic mutations derived from recent whole-genome/exome data sets is then reviewed including those that drive disease pathogenesis from precursor states as well as those that may impact clinical outcomes. We then transition and attempt to elucidate how both chromosomal abnormalities and gene mutations are evolving our understanding of disease risk. We conclude by offering our perspectives moving forward as to how we might apply whole-genome/exome-level data in addition to routine cytogenetic analyses to improve patient outcomes as well as further knowledge gaps that must be addressed. [ABSTRACT FROM AUTHOR]

• Vanadium addition causes an increase in both yield strength and yield ratio. • Vanadium addition reduces strain hardening ability, and weakens wear resistance. • RCF crack initiation of V-alloyed stee is delayed by increasing yield strength. • RCF crack growth size is restricted by reducing plastic deformation capacity. • Increasing yield ratio improves RCF resistance, but weakens wear resistance. This study aims to evaluate the effect of vanadium microalloying on rolling contact fatigue (RCF) and wear behavior of railway wheel steels. It involves microstructural analysis and mechanical testing, including hardness, tensile, and rolling/sliding tests on the test steels, followed by electron backscatter diffraction, residual stress, and microhardness analyses after rolling/sliding tests. The findings demonstrate that vanadium microalloying leads to the alleviation of dynamic recrystallization, strain hardening, and compressive residual stress within the outermost layer beneath the worn surface, indicating a reduction in the plastic deformation capacity during dry rolling/sliding conditions. RCF resistance of railway steel can be enhanced through vanadium microalloying, as it simultaneously delays crack initiation by increasing yield strength and restricts crack growth by reducing plastic deformation capacity. While vanadium microalloying enhances the matrix hardness of wheel steel, it concurrently diminishes its strain hardening ability, potentially compromising its wear resistance. In addition, this study found that the yield ratio, being indicative of plastic deformation capacity and strain hardening ability, can serve as a suitable parameter for characterizing the RCF and wear resistances of tested steels. It exhibits a positive correlation with RCF resistance and a negative correlation with wear resistance. [ABSTRACT FROM AUTHOR]

High temperature superconducting (HTS) maglev transportation has provided a new development direction for high-speed and ultra-high-speed rail transit. In order to promote the development of HTS materials in this area, the dynamic response of the vehicle superconductor under an alternating magnetic field with high frequency is well-worth studying. However, limited by some experimental conditions and other factors, the effective modelling method becomes an indispensable and cost-effective tool to predict the electromagnetic properties of the superconductors. In this paper, based on the single-peaked permanent magnet guideway (PMG)-HTS bulks maglev configuration, the modelling using three different E-J relationships include the power law model (PLM), the flux flow and creep model (FFCM), and the flux flow model (FFM) are compared. Results indicate that the PLM has the highest computational efficiency and good reliability. Then, using the PLM, we further study the dynamic response of the HTS bulks over a Halbach-typed PMG under higher vibration frequencies. The effect of the magnet failure in the middle of the PMG on the levitation system is also discussed. A finite element method is applied with the H formulation. The moving mesh is used to realize the relative displacement between the PMG and HTS bulks. To investigate the temperature rise and the AC loss inside the HTS bulks, the Heat Transfer module is coupled. Results show that the temperature inside the HTS bulks will decay exponentially with time if the magnitude and frequency of the external magnetic field do not continue to increase. This work can provide some references for the future practical applications of the high-speed HTS maglev. [ABSTRACT FROM AUTHOR]

Aims: To realize the so-called "Second Green Revolution", it is imperative to study the roots of crop plants, and identify those traits that improve the efficiency of nitrogen (N) acquisition. We aimed to evaluate how the N acquisition efficiency of six hybrid maize lines commonly grown in northern China depends on their root anatomy. Methods: Maize hybrids classified as having high nitrogen uptake efficiency (HNUE) and low nitrogen uptake efficiency (LNUE) were grown under high-N and low-N conditions in the greenhouse and the field. Results: Under N stress in the field and the greenhouse, HNUE increased shoot dry weight, root length density, N content and nitrogen use efficiency compared to LNUE. Low N availability increased the percentage of root cortical aerenchyma and the size of cortical cells. Root anatomy, with greater formation of root cortical aerenchyma and larger cortical cell size, was associated with increased specific nitrogen absorption efficiency (SNAE) and shoot biomass under N stress. Under low N availability, the percentage of aerenchyma and their total area had significant positive correlations with the shoot dry weight, total N uptake, SNAE. Conclusions: The results suggest that plants in limited N availability form more root cortical aerenchyma and have larger cortical cells, which is of benefit to root growth, soil exploration, N acquisition, and shoot biomass. These observations support the hypothesis that root anatomical phenotypes that affect the metabolic and construction costs of producing root length merit consideration as selection criteria for breeding to improve N acquisition in hybrid maize. [ABSTRACT FROM AUTHOR]

The TANK-binding kinase 1 (TBK1) is a serine/threonine kinase belonging to the non-canonical inhibitor of nuclear factor-κB (IκB) kinase (IKK) family. TBK1 can be activated by pathogen-associated molecular patterns (PAMPs), inflammatory cytokines, and oncogenic kinases, including activated K-RAS/N-RAS mutants. TBK1 primarily mediates IRF3/7 activation and NF-κB signaling to regulate inflammatory cytokine production and the activation of innate immunity. TBK1 is also involved in the regulation of several other cellular activities, including autophagy, mitochondrial metabolism, and cellular proliferation. Although TBK1 mutations have not been reported in human cancers, aberrant TBK1 activation has been implicated in the oncogenesis of several types of cancer, including leukemia and solid tumors with KRAS-activating mutations. As such, TBK1 has been proposed to be a feasible target for pharmacological treatment of these types of cancer. Studies suggest that TBK1 inhibition suppresses cancer development not only by directly suppressing the proliferation and survival of cancer cells but also by activating antitumor T-cell immunity. Several small molecule inhibitors of TBK1 have been identified and interrogated. However, to this point, only momelotinib (MMB)/CYT387 has been evaluated as a cancer therapy in clinical trials, while amlexanox (AMX) has been evaluated clinically for treatment of type II diabetes, nonalcoholic fatty liver disease, and obesity. In this review, we summarize advances in research into TBK1 signaling pathways and regulation, as well as recent studies on TBK1 in cancer pathogenesis. We also discuss the potential molecular mechanisms of targeting TBK1 for cancer treatment. We hope that our effort can help to stimulate the development of novel strategies for targeting TBK1 signaling in future approaches to cancer therapy. [ABSTRACT FROM AUTHOR]

• The overset mesh technology is used to simulate the train running in the tube. • The flow topology considering the ground effect has been visualized numerically. • The influence of the nose length on the wave systems is reported. • Two distinct mechanisms for the formation of flow separation are identified. • The relationship between the aerodynamic loads and flow structures is described. The flow structure and aerodynamic loads in evacuated tube transportation with three nose lengths (5, 10 and 15 m) at 1500 km/h are investigated by overset mesh technology. The governing equations of the IDDES model for 3-D, unsteady compressible flow are employed. The numerical algorithm is validated via moving model and wind tunnel experimental data. The flow topology considering the ground effect is revealed and compared. The wake is highly complex, characterized mainly by wave systems and trailing vortices. Additionally, the influence of the nose length on the generation of wave systems is discussed in detail. The largest shock intensity is identified at 5 m case, followed by 15 m case, and the smallest case at 10 m. Differences in wave systems also caused the two distinct mechanisms for the formation of flow separation and the evolution pattern of the wake vortex to be identified for three nose configurations. By comparison, the nose length increase is helpful to reduce the length of the disturbed region of the leading shock wave, the aerodynamic loads on the train surface and aerodynamic drag. A qualitative description is also presented of the relationship between the fluctuations of aerodynamic loads and flow structures. [ABSTRACT FROM AUTHOR]

The appropriate increase of planting densities is the key to the obtainment of high-yield maize (Zea mays L.). However, lodging is a major constraint to limit grain yield under increased planting density in present maize production. Effects of population density on stalk lodging and agronomic traits were investigated using two maize cultivars Denghai 618 (DH618, low stalk with low spike height) and Xianyu335 (XY335, high stalk with high spike height). Four levels of density treatment were imposed by 1.5, 6.0, 7.5, and 9.0 × 104 plants ha−1. Results showed that bending strength, rind penetration strength, maximum bending strength, dry weight, and internode diameter of maize were significantly decreased with the increase of planting density. The change range of XY335 with the increase of planting density was significantly larger than that of DH618, showing a high sensitivity to planting density. In addition, the thickness of cortex and vascular bundle sclerenchyma cells was significantly reduced with the increase of planting density. Compared with 1.5 × 104 plants ha−1, the thickness of the above-ground third internode stem cortex was decreased by 9.64%, 12.72%, and 20.77% for DH618, and 19.26%, 30.49%, and 37.45% for XY335 at 6.0, 7.5, and 9.0 × 104 plants ha−1, respectively. The thickness of vascular bundle sclerenchyma cells at 1.5 × 104 plants ha−1 was decreased by 7.75%, 12.44%%, and 17.89% for DH618, 10.18%, 15.21%, and 24.73% for XY335, compared to those at 6.0, 7.5, and 9.0 × 104 plants ha−1, respectively. Visibly, with the increase of planting density, the thickness of cortex and vascular bundle sclerenchyma cells, and the number of vascular bundles were all significantly decreased, resulting in the increase of lodging rate. However, the extent of variation in these parameters for short-plant height hybrid was less than those for high-plant height hybrid, and the yield of short-plant height hybrid was greater than that of high-plant height hybrid, indicating that short-plant height hybrid has better resistance to lodging with higher yield at higher planting density. Therefore, lodging resistance and yield can be improved through selection and breeding strategies that achieving synergistic development of diameter, dry weight per unit, and cortex thickness in maize basal internodes. [ABSTRACT FROM AUTHOR]

Both MLL-AF9 and MLL-ENL leukemia fusion proteins drive oncogenic transformation of hematopoietic cells through their N-terminal DNA/histone binding mixed-lineage leukemia 1 domain and C-terminal fragment of AF9 or ENL containing an unstructured linker region and the ANC1 homology domain, which recruits transcription factors. Despite of their structural similarity, acute myeloid leukemia (AML) patients bearing MLL-ENL show more adverse outcomes compared to those with MLL-AF9. We recapitulated the clinical patterns of these two MLL-fusions driven AMLs using murine models and found that MLL-ENL AML cells showed slower cell cycle progression and more resistance to standard chemotherapy than MLL-AF9 cells. These phenotypes were primarily controlled by the linker regions of ENL and a highly conserved lysine residue K469 within. Substitution of K469 with an acetylated mimic glutamine abolished the ability of MLL-ENL to suppress proliferation and promote chemo-resistance. We showed that deacetylase Sirt2 might act as an upstream regulator of MLL-ENL. Deletion of Sirt2 promoted proliferation of AML cells with either MLL fusions. Importantly, loss of Sirt2 greatly enhanced the sensitivity of the MLL-ENL AML cells to chemo-treatment. Taken together, our study uncovered a unique regulatory role of Sirt2 in leukemogenesis and suggested targeting SIRT2 as a new way to sensitize MLL-ENL AML patience for chemotherapy. • Murine MLL-ENL AML cells are slow cycle and relative resistant to chemotherapy compared to MLL-AF9 AML cells. • The proliferation of MLL-ENL AML cells is repressed by the linker sequence of ENL. • The proliferation of MLL-ENL AML cells is repressed by SIRT2. • The proliferation of MLL-ENL AML cells is regulated by the lysine residue at 469 position of ENL linker region. [ABSTRACT FROM AUTHOR]

Summer maize is frequently subjected to waterlogging damage because of increased and variable rainfall during the growing season. The application of 6‐benzyladenine (6‐BA) can effectively mitigate the waterlogging effects on plant growth and increase the grain yield of waterlogged summer maize. However, the mechanisms underlying this process and the involvement of 6‐BA in relevant signal transduction pathways remain unclear. In this study, we explored the effects of 6‐BA on waterlogged summer maize using a phosphoproteomic technique to better understand the mechanism by which summer maize growth improves following waterlogging. Application of 6‐BA inhibited the waterlogging‐induced increase in abscisic acid (ABA) content and increased the phosphorylation levels of proteins involved in ABA signaling; accordingly, stomatal responsiveness to exogenous ABA increased. In addition, the application of 6‐BA had a long‐term effect on signal transduction pathways and contributed to rapid responses to subsequent stresses. Plants primed with 6‐BA accumulated more ethylene and jasmonic acid in response to subsequent waterlogging; accordingly, leaf SPAD, antioxidase activity, and root traits improved by 6‐BA priming. These results suggest that the effects of 6‐BA on hormone signal transduction pathways are anamnestic, which enables plants to show faster or stronger defense responses to stress. [ABSTRACT FROM AUTHOR]

In this work, the real maglev train and tube are modeled. Considering the narrow suspension gap, the aerodynamic characteristics in evacuated tube transportation with and without tracks (referred to as WT and NT (no tracks), respectively) are simulated based on the SST k - ω two-equation IDDES turbulence model and overset mesh technology, the wave system distribution characteristics under the asymmetric model are revealed and the effects of tracks on flow and heat transfer are discussed. The results demonstrate that the existence of the tracks increases the piston region by 0.005 L (L represents the length of the train). Additionally, the tracks have a significant impact on the evolution of the wake vortex. The unstable vortices dissipate more energy and reduce the effect of the wave system in the WT case, resulting in a 0.024 L shorter wake region than in the NT. Besides, the tracks hardly affect the drag force coefficient. However, the tracks cause a more significant impact in the vertical direction, resulting in an up to 23.20% reduction of lift coefficient of the overall train in the NT model. In terms of aerodynamic heating, the effect of the tracks on the shock wave generated at the tail curve bottom is greater than the top surface. • The aerodynamic characteristics inside the tube are simulated by IDDES. • The wave system under the two ground cases, with and without tracks, is compared. • Considering the suspension gap, the wave system presents obvious up–down asymmetry. • The tracks have a significant impact on the evolution of the wake vortex. • The existence of tracks reduce the effect of wave systems. [ABSTRACT FROM AUTHOR]

With the extensive promotion of controlled-release urea (CRU), its N-release pattern has been shown to match the crop's N-demand period and improve crop yield by reducing N losses. Nevertheless, the impacts of CRU on summer maize yield, especially on greenhouse gas emissions, have rarely been reported during its long-term use. It is necessary through long-term positioning field experiment with CRU application to investigate the regulatory mechanisms of maize yield formation, nitrogen use efficiency (NUE), ammonia volatilization and greenhouse gas emissions. The long-term fertilizer positioning experiment for ten years, four treatments were performed: polymeric-coated controlled-release urea (CRF, 42% N, 3-months controlled-release period), sulfur-coated controlled-release urea (SCF, 35% N, 3-months controlled-release period), common urea (CCF, 46% N) and no nitrogen fertilizer (CK). Results showed that the two coated controlled-release fertilizers significantly increased NUE and dry matter accumulation in summer maize, and ultimately improved grain yield. Compared to CCF, CRF and SCF treatments increased post-silking dry matter accumulation by 16.3% and 13.3%; NUE by 42.3% and 28.9%. The 2-year mean grain yield of CRF and SCF treatment increased 9.0% and 12.4% compared to CCF treatment. CRF treatment significantly increased the NO 3 --N content in 0–60 cm soil layer; while CRF and SCF treatments showed a significantly higher NH 4 +-N concentration in the 0–20 cm soil layer than CCF treatment. Compared to CCF treatment, the CRF and SCF treatments significantly reduced peak ammonia volatilization, and the average cumulative emissions of ammonia volatilization of two years were reduced by 80.8% and 53.2%, respectively. CRF treatment had lower peak of N 2 O emissions but longer N 2 O emission duration than other N application treatments. The two-year average cumulative N 2 O emissions from CRF treatment increased by 49.6%, and SCF treatment increased by 61.1% compared to CCF treatment. Compared to CK treatment, total cumulative CH 4 uptake was 36.1% lower in CRF treatment, 60.9% in SCF and 78.9% in CCF treatment. The higher cumulative N 2 O emissions from CRF and SCF treatment resulted in a significantly higher global warming potential (GWP) than CCF treatment. The two-year mean increase in greenhouse gas intensity (GHGI) was 36.2% for CRF treatment and 44.7% for SCF treatment compared to CCF treatment. Long-term application of coated controlled-release fertilizers could achieve high yields and nitrogen use efficiency. However, there is a risk of increased N 2 O emissions, causing elevated GHGI. In the future, it is necessary to strengthen the research on the comprehensive effects of long-term reduced application of CRU on crop yield and greenhouse gas emissions, in order to promote the wide application of environmentally friendly CRU in the field. [Display omitted] • Long-term application of CRU could achieve sustainable crop yield improvement. • Long-term application of CRU significantly reduced ammonia volatilization and CH 4 emissions. • Long-term application of CRU carried the risk of increased N 2 O emissions, leading to higher GHGI. [ABSTRACT FROM AUTHOR]

• The preferentially dissolved ferrite in pearlite and shedding of cementite lamellae contribute to the formation of corrosion pits. • Corrosion fatigue crack initiation and growth mechanism of U75V rail steel is clarified. • Corrosion fatigue crack initiation behavior is related to morphology ratio and local shape of corrosion pits. Understanding the corrosion fatigue mechanism of rail materials is of great importance to guide the assessment of the structural integrity of modern railway components. To this purpose, the corrosion fatigue crack (CFC) initiation and growth behaviors of heat-treated U75V rail steel are investigated under 3.5 wt% NaCl solution in terms of high-cycle fatigue, fatigue crack growth (FCG) rate, together with surface morphology and microstructure. Experimental results reveal that the U75V rail steel is susceptible to corrosion fatigue failure. Examinations on fractured samples clearly show that the electric potential difference between ferrite and cementite triggers the preferential anodic dissolution of ferrite, leading to corrosion fatigue crack initiation. The crack initiation is not only solely determined by the size of the corrosion pit, but also strongly influenced by its local shape. In comparison with the fatigue crack growth in air, the corrosion FCG tends to grow in a relatively straight path, because of hydrogen embrittlement. Additionally, the CFC behaviors indicate a tendency to transverse through soft-oriented grains and deflect upon encountering hard-oriented grains. [ABSTRACT FROM AUTHOR]

RIPK3 (receptor-interacting protein kinase 3) is a serine/threonine-protein kinase. As a key component of necrosomes, RIPK3 is an essential mediator of inflammatory factors (such as TNFα-tumor necrosis factor α) and infection-induced necroptosis, a programmed necrosis. In addition, RIPK3 signaling is also involved in the regulation of apoptosis, cytokine/chemokine production, mitochondrial metabolism, autophagy, and cell proliferation by interacting with and/or phosphorylating the critical regulators of the corresponding signaling pathways. Similar to apoptosis, RIPK3-signaling-mediated necroptosis is inactivated in most types of cancers, suggesting RIPK3 might play a critical suppressive role in the pathogenesis of cancers. However, in some inflammatory types of cancers, such as pancreatic cancers and colorectal cancers, RIPK3 signaling might promote cancer development by stimulating proliferation signaling in tumor cells and inducing an immunosuppressive response in the tumor environment. In this review, we summarize recent research progress in the regulators of RIPK3 signaling, and discuss the function of this pathway in the regulation of mixed lineage kinase domain-like (MLKL)-mediated necroptosis and MLKL-independent cellular behaviors. In addition, we deliberate the potential roles of RIPK3 signaling in the pathogenesis of different types of cancers and discuss the potential strategies for targeting this pathway in cancer therapy. [ABSTRACT FROM AUTHOR]

As with most organ systems that undergo continuous generation and maturation during the transition from fetal to adult life, the hematopoietic and immune systems also experience dynamic changes. Such changes lead to many unique features in blood cell function and immune responses in early childhood. The blood cells and immune cells in neonates are a mixture of fetal and adult origin due to the co-existence of both fetal and adult types of hematopoietic stem cells (HSCs) and progenitor cells (HPCs). Fetal blood and immune cells gradually diminish during maturation of the infant and are almost completely replaced by adult types of cells by 3 to 4 weeks after birth in mice. Such features in early childhood are associated with unique features of hematopoietic and immune diseases, such as leukemia, at these developmental stages. Therefore, understanding the cellular and molecular mechanisms by which hematopoietic and immune changes occur throughout ontogeny will provide useful information for the study and treatment of pediatric blood and immune diseases. In this review, we summarize the most recent studies on hematopoietic initiation during early embryonic development, the expansion of both fetal and adult types of HSCs and HPCs in the fetal liver and fetal bone marrow stages, and the shift from fetal to adult hematopoiesis/immunity during neonatal/infant development. We also discuss the contributions of fetal types of HSCs/HPCs to childhood leukemias. [ABSTRACT FROM AUTHOR]

• Fatigue tests are conducted for small specimen and press-fitted axle with defect. • Press-fitted axles exhibit notably lower fatigue strength than small specimens. • Goodman relation is used to consider mean tensile stress induced by press-fitting. • The error of predicted notch fatigue strength is controlled to less than 11%. In order to evaluate the notch fatigue strength of transition groove in railway axle, a series of fatigue tests were conducted on small specimens and press-fitted axles containing surface defects. Based on the experimental and finite element (FE) analyses, a novel method considering mean stress effect was proposed to evaluate the fatigue strength of scale railway axle with surface defect. It is found that press-fitted axles exhibit significantly lower notch fatigue strength than small specimens. Furthermore, the theory of critical distance (TCD) provides a good correlation between the notch fatigue strength of small specimens and experimental results. FE analyses revealed that the press-fitting reduces the fatigue strength of the transition groove through increasing stress concentration and introducing a mean tensile stress that decreases with an increase in the applied loading. To account for the mean stress effect, the axial stress at the groove is corrected as an equivalent stress amplitude at R = -1 based on Goodman relation. Through the combination of TCD and Goodman relation, an estimated fatigue strength with an error of less than 11 % can be achieved for the scale railway axle with surface defect. [ABSTRACT FROM AUTHOR]

Global climate change has significantly increased the frequency and intensity of high temperature and drought stresses. Additionally, the high temperature and drought are often concurred, which make the situation of maize production tougher. However, the influence of the combined stresses of high temperature and drought on summer maize production remains uncertain. The study aimed to investigate the effects of high temperature, drought, and their combined stress at different growth stages on photosynthetic and senescence characteristics of summer maize. Denghai 605 (DH605) was used as the experimental material. High temperature (T), drought (D), and their combined stress (T-D) for 6 days were set at the 3rd leaf stage, 12th leaf stage, and tasseling stage, respectively. The natural temperature and normal water management were used as the control (CK). The results showed that high temperature, drought, and their combined stress at different growth stages decreased the activities of antioxidant enzymes and soluble protein content in leaves, leading to increases in MDA content and damage to cell membranes, which accelerated the senescence of the plant. Accordingly, the activities of RuBPcase and PEPCase were decreased, indicating the abilities of plants to harvest and utilize light energy declined due to high temperature, drought, and combined stresses at different growth stages. As a result, the Pn and thus, the dry matter accumulation rate were decreased by these stresses. In addition, the translocation of dry matter to ears was impeded by stresses, especially by the high temperature at the VT stage. While, high temperatures concurred with drought aggravated the adverse effects on summer maize, compared with single stresses. Significantly, high temperature, drought, and their combined stresses at the VT stage decreased the yield mostly, followed by stresses at the V12 stage, and then by stresses at the V3 stage. Compared with CK, the yield of VT-T-D, V12-T-D, and V3-T-D were decreased by 61.6 %, 13.7 %, and 10.4 %, respectively. As global climate change is unstoppable, the superimposed changes of various meteorological factors make the growth conditions for crop production extreme. Studies to explore the combined effects of two or even more meteorological factors on crop growth are becoming more and more important. This study fulfilled the current knowledge gap of the combined stresses on maize production, however, the underlying mechanisms should be dug out in the future. • High temperature, drought and their combined stress at different growth stages accelerated the senescence of the plant. • Drought concurred with high temperature aggravated the adverse effects on summer maize, compared with single stresses. • Drought concurred with high temperature certainly aggravated the increases of VPD, straining the relationship of CO 2 intakes and water losses. [ABSTRACT FROM AUTHOR]

How to improve nitrogen (N) efficiency and reduce environmental pollution caused by N loss has attracted much attention. However, limited research has lacked a comprehensive exploration of the effects of applying UAN under the micro sprinkling fertigation on reactive N (Nr), fertilizer efficiency and net benefits including environmental costs, plus associated responses of the microbial metagenome. The aim of this study was to assess the impact of N management practices on maize yield, Nr losses, and soil microbial community composition and function. Urea and urea ammonium nitrate solution (UAN) were used as N sources, and three N application rates (210, 168 and 0 kg N ha−1) and two fertilization methods (micro sprinkling fertigation and traditional fertilization) were set as the three key components. The results showed that micro sprinkling fertigation treatments reduced Nr losses, increased yield and N efficiency. Compared with urea, the total NH 3 volatilization and N 2 O emissions of UAN under micro sprinkling fertigation were decreased by 14.8% and 30.6%, respectively. Furthermore, the N reduction (FU1) treatment promoted plant N uptake, was saved 20% of N by affecting soil NH 4 +- N and NO 3 --N content, compared to that of urea, and it regulated the microbial abundance of N cycle function related to denitrification and N respiration, reduced global warming potential and greenhouse gas emission intensity. N application method, N source and N rate affected the diversity and composition of soil bacterial community, and altered Nr emissions by changing the abundance of functional microorganisms related to N cycle. Overall, improved N management practice was more conducive to increasing maize yield and net income, saving N resources, and reducing the risk of environmental damage. Our results contribute to a comprehensive understanding of the impact of N management on summer maize production, providing an effective N management practice that is conducive to "green agricultural development". [Display omitted] • A field trial was conducted in Huang-Huai-Hai Plain of China to clarify N losses and net income. • The soil bacterial community was changed by fertilization methods and N sources. • Applying UAN under micro sprinkling fertigation improved maize yield and saved N resources. [ABSTRACT FROM AUTHOR]

Energy analysis of agricultural production is essential to promote sustainable agricultural development. However, the current research on agricultural sustainability in the North China Plain (NCP) mainly focuses on improving grain yield and nitrogen utilization efficiency (NUE), while there are few studies on their energy utilization. This study evaluated the energy utilization characteristics of different yield and NUE category farms and three integrated agronomic approaches in the NCP based on farmer surveys and farm experiments. Compared with the average level of smallholder farms, the net energy (NE) and the energy utilization efficiency (EUE) of high-yield and high-NUE group farms increased by 17% and 22%, respectively, the NE of the high-yield and low-NUE group farms increased by 9%, but the EUE decreased by 12%. The control experiment showed that the NE and EUE achieved using high-yield and high-efficiency agronomic practice (HH) increased by 34% and 18% compared with achieved using traditional farmers' practices, respectively. In conclusion, there is a great opportunity to improve the NE and EUE of the maize production in the NCP by optimizing agronomic practices. Popularizing HH technology by improving agricultural technology extension services is of great significance for improving farmers' EUE and promoting sustainable agricultural development. • Quantitative analysis of the NE and EUE of maize production systems in the NCP. • Improving the EUE for maize production requires an overhaul of management practices. • Adopting HH production practices could simultaneously improve the NE and the EUE. [ABSTRACT FROM AUTHOR]

The application of nitrogenous fertilizer synergist to coordinate nitrogen transformation process in soil may be an efficient strategy to increase nitrogen use efficiency and decrease environmental pollution. However, there are few reports on the application effects of UAN synergistic nitrification and urease inhibitors under the integration of water and fertilizer. This study aimed to explore effects of urea ammonium nitrate solution (UAN) combined with urease and nitrification inhibitors on yield and nitrogen efficiency of summer maize and its ecological effects under the fertigation, and to provide scientific basis for the efficient utilization of UAN. The experimental treatments were as follows: no inhibitor treatment (U), nitrification inhibitor treatment (U-D), urease inhibitor treatment (U-N), and the combination of nitrification and urease inhibitors treatment (U-D+N). Results showed that UAN combined with urease or nitrification inhibitors could significantly reduce the cumulative emission of N 2 O, and then significantly decreased the N 2 O warming potential (GWP N2O) and N 2 O greenhouse gas intensity (GHGI N2O). Compared with U treatment, the cumulative N 2 O emissions of U-D+N, U-N, and U-D treatments was reduced by 45.7 %, 25.3 % and 35.8 %, respectively. The GWP N2O of U-D+N, U-N and U-D treatments decreased by 45.7 %, 25.3 % and 35.7 %, while GHGI N2O decreased by 50.9 %, 30.3 % and 38.9 % on average, respectively, compared to those of U treatment. Application of urease inhibitors significantly reduced NH 3 volatilization. The cumulative NH 3 volatilization of U-N and U-D+N treatments was reduced by 30.7 % and 23.4 %, while U-D treament was significantly increased by 12.3 %, respectively, compared to that of the U treatment. In addition, UAN combined with urease or nitrification inhibitor could significantly increase the contents of NO 3 --N and NH 4 --N in the 0–20 cm soil layer, and significantly reduced the leaching of NO 3 --N to the deep soil. The total nitrogen accumulation, grain nitrogen content, nitrogen transport efficiency and post-anthesis assimilation of summer maize were significantly increased, which were beneficial to the improvement of grain yield and economic benefits. under the fertigation, the synergistic application of UAN with urease and nitrification inhibitors were beneficial to reduce greenhouse gas emissions and ammonia volatilization, improved the nitrogen use efficiency, and then improved the yield and economic benefits of summer maize. Under the fertigation, UAN combined with urease and nitrification inhibitors were beneficial to emission reduction, high yield, and high efficiency. [Display omitted] • The combination of DCD and NBPT reduced N 2 O and NH 3 emission under fertigation. • The combination of UAN with DCD and NBPT improved N use efficiency under fertigation. • The combination of UAN with DCD and NBPT increased maize yield under fertigation. [ABSTRACT FROM AUTHOR]

In order to improve the grain yield of food crops, which is necessary to ensure food security, it is crucial to narrow existing yield gaps. Quantitative analyses of crop yield gaps can provide theoretical support for ascertaining the primary cause of these yield gaps, and then it can be used to increase the grain yield. We evaluated the size and characteristics of the summer maize yield gap in the North China Plain by combining crop models, farmer surveys, and farm experiments. We simulated the summer maize population of farmers' yield level, attainable yield level and potential yield level by establishing three cultivation modes: traditional farming practices (FP), established high-yield and high-efficiency practices (HH) and super-high-yield practices (SH), and introduce the cultivation relying solely on the basic soil fertility (BSF) to reveal the impact of environmental and management factors on yield gap. We explored the driving factors causing observed variations of yield gaps through a quantitative analysis of several additional parameters that are commonly used to characterize the efficiency of the maize production process, including the contribution rates of dry matter and harvest index to grain yield, the radiation interception rate and the radiation conversion efficiency. Our results show that the total yield gap based on farmer surveys and crop models was 4.9 t ha-1, accounting for 37% of the potential yield, of which 46% was exploitable. The total yield gap based on the farm experiments was 3.9 t ha-1, accounting for 30% of the potential yield, of which 69% was exploitable. The grain yield of FP significantly positively correlated with the grain yield of BSF, HH and SH. The contribution rates of dry matter and harvest index to grain yield of FP treatment were 45.7% and 54.3%, respectively. With the increase of yield level, the contribution rate of dry matter increased and the contribution rate of harvest index decreased. In summary, we found a sizeable total yield gap in summer maize in the North China Plain, and a considerable part is exploitable. Optimizing integrated agronomic management has a great potential for closing the exploitable yield gap. Narrowing the yield gap requires a synergistic increase in the contribution rate of dry matter and harvest index to grain yield, but a substantial increase in dry matter is more important. At present, narrowing the exploitable yield gap requires synergistic improvement of radiation interception rate and radiation conversion efficiency to increase the dry matter of maize population. In the future, the regulation measures aiming at narrowing the unexploitable yield gap should further focus on improving the radiation conversion efficiency. • Quantification of the exploitable and unexploitable yield gaps for maize in the NCP. • Dry matter and harvest index contributions to maize grain formation depend on the yield level. • Suggestions for improving the productivity of established maize farming practices. [ABSTRACT FROM AUTHOR]

3 Root anatomy parameter of different NUE maize varieties at 40 days in the greenhouse under high-N and low-N conditions. A, RXSA, root cross-section area; B, TCA, total cortex cross-section area; C, TSA, total stele cross-section area; D, AA, total aerenchyma area; E, CCA, cortical cell area; F, MXVA, total metaxylem vessel area; G, CCS, median cortical cell size; H, MXA, median single metaxylem vessel area; I, AAP, percentage of aerenchyma area in the cortex; J, CFN, number of cortical cell files; K, MXN, number of metaxylem vessels; L, MXP, percentage of total metaxylem vessel area in the stele The gray bar and pink bar represent the HNUE and LNUE group, respectively. [Extracted from the article]

In the Huang-Huai-Hai region of China, continuous rain is the main meteorological constraint for summer maize, accompanied by stresses of both waterlogging and shading. To evaluate the independent and combined effects of shading and waterlogging on summer maize at different stages, a field experiment was performed to study the grain yield, crop growth, and canopy functionality of summer maize in response to waterlogging (W), shading (S), and their interaction for a 6 day period starting at the third leaf stage (V3), the sixth leaf stage (V6), and the tasseling stage (VT). Shading, waterlogging, and their combination stress (S+W) significantly decreased the grain yield of summer maize. Among these, the simultaneous stress induced greater yield losses than single stresses at any growth stage. The reduction of yield induced by waterlogging at early and late stages differed from 20–40 % to 3–16 %. Shading at VT stage induced most serious losses of grain yield. The grain yield of summer maize was closely related with the crop biomass accumulation. Shading, waterlogging, and their combination stress significantly decreased leaf area index resulting in serious reduction of the radiation interception. Besides, the leaf SPAD value and photosynthetic rate were also significantly reduced by the stresses, which led to notable reduction in radiation use efficiency (RUE) of summer maize. Thereby, the total accumulated crop biomass was decreased. Moreover, the biomass partitioning to ears was decreased. Accordingly, the 1000-kernel weight and kernels per ear were decreased by the stresses, leading to yield losses. This study explored the differential responses of radiation interception, canopy functionality, and RUE to waterlogging, shading, and their combined stress at different growth stage, furthering our understanding on the yield and growth for summer maize crops under persistent rainfall conditions. • The response of yield components to combined stress at different stage was differed. • Waterlogging at early stage reduced radiation interception and RUE decreasing yield. • Shading at VT lowered incident radiation, decreased kernel setting reducing the yield. • The combined effects of shading and waterlogging on grain yield was greater than single stress. [ABSTRACT FROM AUTHOR]

In the North China Plain (NCP), the deployment of sub-optimal crop management methods has resulted in low maize grain yields and significant environmental costs arising from a low N partial factor productivity (NPFP) and a rampant greenhouse gas emission intensity (GHG i). We hypothesize that in-situ analysis of the grain yield, NPFP and GHG i at local farms might contribute to improving the crop yield, as well as the environmental sustainability of maize production systems. In this study, we investigated the maize production systems deployed at 1574 local farms in the NCP, and quantified the total yield gap (defined as the difference between the yield potential as simulated by the DSSAT-CERES-Maize model and the actual yield achieved by farmers) and the exploitable yield gap (defined as the difference between the attainable yield as calculated by using the Boundary Line Function (BLF) analysis and the average actual yield achieved by farmers). By combining the results from crop modelling, farmer survey data, and on-farm trials, we were able to identify the dominant factors driving the variability in summer maize yield, NPFP, and GHG i. The results revealed that the average grain yield for summer maize in the NCP was 8.3 t ha−1, and that the total and exploitable yield gaps were 4.9 t ha−1 and 3.0 t ha−1, respectively. The average NPFP was 41 kg kg−1, which amounts to 54% of the attainable NPFP. The average GHG i was 463 kg CO 2 eq t−1 grain, which constitutes an increase of 119% over the attainable GHG i. The main factors driving yield include the harvest date and the planting density, and the main factors driving NPFP and GHG i include the N, P and K fertilization rate, where it should be noted that these factors exhibit regional differences. After testing our optimized integrated agronomic management measures in the field experiments, we could confirm that it is possible to narrow the yield gap by 2.7 t ha−1, increase NPFP by 38%, and reduce GHG i by 28%. Obviously, optimizing integrated agronomic management has a great potential for narrowing the yield gap and improving the sustainability of agricultural production. • The total and exploitable yield gaps of maize in the NCP are 4.9 and 3.0 t ha−1. • The main factors driving yield include the harvest date and the planting density. • The N, P and K fertilization rate driving the variability in NPFP and GHG i. • Agronomic optimizations can improve the yield and sustainability of farms in the NCP. [ABSTRACT FROM AUTHOR]