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Screening for low-accumulation varieties is an effective way to reduce the cadmium (Cd) content in crops and decrease human Cd intake. In this study, a field experiment was conducted to analyze the characteristics of Cd absorption and accumulation in 24 maize varieties at maturity in farmland with different levels of Cd pollution. Cluster analysis and Pareto analysis methods were used to screen for maize varieties with low Cd absorption. In addition, the environmental threshold of Cd in farmland in the study area was estimated based on the Species Sensitivity Distribution (SSD) characteristics of different maize Cd enrichment coefficients (1/BCF). The results showed that maize in the study area was subject to varying degrees of Cd pollution, with total soil Cd content ranging from 1.81 to 2.71 mg·kg−1 at test site 1 and from 0.95 to 1.76 mg·kg−1 at test site 2. Only the Cd content of heavy metals in maize kernels at test site 2 did not exceed China's national food safety standard (GB 2762-2022, 0.1 mg·kg−1), with the Cd content of different maize varieties at test site 2 ranging from 0.008 to 0.073 mg·kg−1 and the bioconcentration factor (BCF) of maize kernels for Cd ranging from 0.004 to 0.054. According to cluster analysis and Pareto analysis, the low-Cd accumulation maize varieties suitable for local planting were identified as Yufeng 303, Nongda 372, Jingnongke 728, MC121 (Fengda Seed Industry), and Jinyu 1233. In addition, the soil Cd environmental threshold for ensuring that 95% of maize would not be polluted by Cd in soil was derived as 1.39 mg·kg−1. [ABSTRACT FROM AUTHOR]

The acquisition of the timing and duration of metamorphic mineral growth is the key to understanding the evolution of metamorphic belts. Garnet Lu–Hf geochronology is becoming increasingly powerful in this aspect. It is believed that garnet Lu–Hf radiometric systems are preserved during low-temperature metamorphism. However, this hypothesis has not been systematically tested. To examine the Lu–Hf systematics of garnets during low-temperature metamorphism, we conducted radiometric dating on individual garnet crystals of different sizes from a single micaschist in the North Qilian orogenic belt. The garnet Lu–Hf dates correlate well with the grain sizes and their core Mn concentrations. The positive correlation between the ages and grain sizes suggests that grain size is a proxy for preserving garnet nucleation and growth history. Small grains nucleated and grew later than large crystals. The Lu–Hf date of the individual garnet crystals faithfully recorded the total growth time span. The date difference of ~16 Myr is the minimum duration of the total garnet growth. The age discrepancy between the micaschist and the eclogite indicates they may not have experienced the same subduction and exhumation in the North Qilian orogenic belt. [ABSTRACT FROM AUTHOR]

Isolates of three endornavirus species were identified co-infecting an unidentified species of Ceratobasidium, itself identified as a symbiont from within the roots of a wild plant of the terrestrial orchid Pterostylis vittata in Western Australia. Isogenic lines of the fungal isolate lacking all three mycoviruses were derived from the virus-infected isolate. To observe how presence of endornaviruses influenced gene expression in the fungal host, we sequenced fungus-derived small RNA species from the virus-infected and virus-free isogenic lines and compared them. The presence of mycoviruses influenced expression of small RNAs. Of the 3272 fungus-derived small RNA species identified, the expression of 9.1% (300 of 3272) of them were up-regulated, and 0.6% (18 of 3272) were down-regulated in the presence of the viruses. Fourteen novel micro-RNA-like RNAs (Cer-milRNAs) were predicted. Gene target prediction of the differentially expressed Cer-milRNAs was quite ambiguous; however, fungal genes involved in transcriptional regulation, catalysis, molecular binding, and metabolic activities such as gene expression, DNA metabolic processes and regulation activities were differentially expressed in the presence of the mycoviruses. [ABSTRACT FROM AUTHOR]

• Fatigue failure mechanism was elucidated for multi-stage centrifugal pump shaft. • Specific technical measures to prevent pump shaft failure were proposed. • Fatigue resistance design is performed for pump shaft structure and coupling. • Feasibility of the new pump shaft system has been verified by experiment. In the operation of multistage centrifugal pump, the pump shaft of 304 stainless steel is subjected to a variety of alternating loads. It is one of the parts prone to failure. The fracture microscopic observation, chemical composition analysis and mechanical property measurement of the fractured pump shaft are carried out. Through the fracture analysis, it is found that the pump shaft failure is caused by fatigue mechanism with characteristic of multi-source crack initiation, and there are many cavities and inclusions at the fracture. From the numerical analysis, it is found that there is significant stress concentration at the fracture, which exceeds the fatigue limit of the material and eventually leads to the fatigue fracture. Besides, the appropriate fillet radius and elastic coupling are designed for the pump shaft, which can effectively reduce the stress concentration and improve the service life of the pump shaft. Finally, the fatigue life of the improved pump shaft was experimentally verified. [ABSTRACT FROM AUTHOR]

Accurate soil management has long been the focus of research in agroecology. Crop productivity can be enhanced while reducing environmental threats from excessive fertilization by fully comprehending the spatial variability of soil properties and delineating management zones (MZs). A field investigation was carried out at experimental sites outside Hefei City's administrative districts in China to study the spatial variability of soil properties and the delineation of MZs. A total of 9601 soil samples were collected in the study area. A variety of soil properties were analyzed, including the pH, organic matter, total nitrogen, alkali-hydrolyzable nitrogen, available phosphorus, available potassium, slowly released potassium, available sulfur, available boron, available copper, available zinc, available iron, and available manganese. The coefficient of variation for various soil properties exhibited a wide range, spanning from 12.2% to 100.5%. The geostatistical results show that most soil properties have moderate to strong spatial autocorrelation, and the ordinary kriging method is used to map the distribution of soil properties. The principal component analysis method was used to reduce the dimension of 13 soil properties to 4 principal components, and the fuzzy c-means clustering method was used to delineate MZs. The calculation results of the fuzzy performance index and normalized classification entropy show that the optimum number of MZs is five. In the study area, the western part exhibits the highest soil fertility, primarily attributed to its elevated organic matter content. Additionally, organic matter emerges as a key factor influencing sustainable agricultural production in this region. These results form the basis for soil managing areas outside the administrative districts of Hefei City. [ABSTRACT FROM AUTHOR]

Islanding detection plays an important role in operation and control of distributed generations (DGs). In this study, a novel hybrid method is proposed, which combines decision tree (DT) with voltage and frequency positive feedbacks for islanding detection in DGs. In the proposed method, the feature indices of prescribed events are captured and recorded in a target location to train a DT classifier, and the classifier can then be used for categorising islanding mode or grid‐connected mode. The voltage and frequency positive feedback schemes are employed to regulate the DG power outputs based on voltage and frequency deviation between DG outputs and rated values. Furthermore, the disturbances are introduced to change the feature indices significantly when DG is switched to islanding mode, which can increase the sensitivities of feature indices and improve detection accuracy. The proposed hybrid method has been fully evaluated and tested on a representative DG system with two DGs. Simulation studies demonstrate that the proposed method can detect the islanding more accurately in situations where the power is balanced between DG output and load consumption, and can also improve detection accuracy in situations where DG system operates in minimum or maximum loading states. [ABSTRACT FROM AUTHOR]

[Display omitted] Solar-driven water splitting has been regarded as a promising strategy for renewable hydrogen production. Among many semiconductor photocatalysts, graphitic carbon nitride (g-C 3 N 4) has received tremendous attention due to its two-dimensional structure, appropriate band gap and decent photocatalytic activity. However, it suffers severe charge recombination problems, affecting its practical performance. In this work, we demonstrated that dual heteroatoms (C and O) doped g-C 3 N 4 can exhibit about 3 times higher catalytic performance for hydrogen evolution than that of the normal g-C 3 N 4 with a hydrogen evolution rate reaching 2595.4 umol g−1h−1 and an apparent quantum efficiency at 420 nm of 16.6%. The heteroatoms (C and O) doped g-C 3 N 4 photocatalyst also exhibited superior removal performance when removing Rhodamine B (RhB). X-ray photoelectron spectroscopy (XPS), solid-state nuclear magnetic resonance (ssNMR) and X-ray absorption near-edge structure (XANES) spectroscopy reveal that the carbon and oxygen dopants replace the sp2 nitrogen and bridging N atom, respectively. DFT calculations demonstrate the codoping of carbon and oxygen- induced the generation of mid-gap state, leading to the improvement of light harvesting and charge separation. [ABSTRACT FROM AUTHOR]

Corona textures, characterized by specific mineral assemblages as layers between existing phases, are frequently observed in high-grade metamorphic rocks. The mechanisms of corona formation have been extensively investigated, however direct dating of corona phases has rarely to be attempted. In order to decipher the timing and duration of corona formation and its implications for metamorphic processes, an integrated garnet Lu–Hf and Sm–Nd and zircon U–Pb petrochronological study was conducted on a corona-bearing granulite from the Miyun region in the North China Craton. The Miyun region, located at the joint area of the Archean Eastern Block and the Paleoproterozoic Trans-North China Orogen, offers a distinctive opportunity to study polymetamorphic processes within the North China Craton. The sample shows a corona texture, primarily composed of garnet, minor clinopyroxene and quartz, that formed at the boundary between plagioclase and orthopyroxene. Pseudosection modelling for the effective bulk composition of reactive domains and conventional thermobarometric calculations indicate that the anhydrous corona assemblage (comprising clinopyroxene, garnet and quartz) formed at ~ 0.9 GPa and ~ 740 ℃. The subsequent hydrous retrogression took place at ~ 0.5 GPa and ~ 670 ℃ and led to the growth of amphibole and biotite. A Lu–Hf garnet date of 1864 ± 3 Ma is significantly younger than the U–Pb date of ca. 2454 Ma for metamorphic zircons in the sample, consistent with the disequilibrium partitioning of rare earth elements between the two phases. The well-preserved Lu zoning in garnet supports the interpretation that the Lu–Hf date represents the age of garnet growth and approximates the timing of formation of the anhydrous corona assemblage. Thus, the U–Pb age reflects a distinct Archean metamorphic event that has been widely documented in high-grade rocks across the Eastern Block of the North China Craton. The garnet Sm–Nd date of 1817 ± 6 Ma is indistinguishable from an amphibole-biotite Lu–Hf date of 1819 ± 16 Ma and ~ 47 Myr younger than the corresponding garnet Lu–Hf date. The younger Sm–Nd age represents the timing of cooling and post-dates retrogression. The Paleoproterozoic and Archean ages in the Miyun granulite align with the major tectonic events in the Trans-North China Orogen and the Eastern Block, respectively. This consistency suggests that the Miyun region likely experienced concurrent metamorphic events in both the Trans-North China Orogen and the Eastern Block. This texture-based Lu–Hf and Sm–Nd dating approach has wide applicability for rocks with explicit textures, facilitating precise extraction of temporal intervals in the metamorphic process. [ABSTRACT FROM AUTHOR]

Scintillators, an important component of optoelectronic materials, have been used extensively for medical imaging and security detection. Currently, most X-ray imaging scintillators rely on inorganic scintillators that use rare earths. Scintillator materials with mild growth conditions, high light yield, environmental friendliness, and low cost are still worth exploring. Here, we prepared novel zero-dimensional (0D) organic-inorganic hybrid zinc halides [C 9 H 14 N] 2 ZnBr 4 (C 9 H 14 N+ = N-butylpyridinium bromide cation) based on pyridine quaternary ammonium salt C 9 H 14 NBr and ZnBr 2. Under UV excitation, the [C 9 H 14 N] 2 ZnBr 4 single crystal shows efficient blue light emission with the center at 426 nm, a large Stokes shift of 129 nm, and a high quantum yield of 49.95 %. In addition, the highly efficient blue emission of [C 9 H 14 N] 2 ZnBr 4 crystals was also able to be excited by X-rays. The [C 9 H 14 N] 2 ZnBr 4 crystal exhibited a relatively low detection limit of 4.995 μGy air s-1. X-ray imaging results based on [C 9 H 14 N] 2 ZnBr 4 scintillation screens demonstrate high-performance X-ray imaging capabilities. According to these results, [C 9 H 14 N] 2 ZnBr 4 crystals are promising X-ray scintillators due to their non-toxicity, excellent luminescence, and good detection performance. [Display omitted] • Novel zero-dimensional organic-inorganic hybrid zinc halide [C 9 H 14 N] 2 ZnBr 4 crystals were synthesized. • Under UV excitation, the [C 9 H 14 N] 2 ZnBr 4 crystals exhibit bright blue light emission. • The electronic properties including energy band structure and density of states were systematically investigated. • Flexible [C 9 H 14 N] 2 ZnBr 4 films prepared as X-ray imaging scintillators exhibit a low detection limit. [ABSTRACT FROM AUTHOR]

Reactor pressure vessel (RPV) is one of the key equipment for nuclear power plant, and long-term exposure to high temperature is an important factor causing its performance deterioration. Under core meltdown conditions, RPV steel experiences high temperature creep due to the In-Vessel Retention (IVR) mitigation measures. This paper aims to investigate high-temperature mechanical properties, especially for the creep behaviors of 16MND5 steel after thermal aging at 650 °C for 2000 h. The results showed that the yield stress and ultimate tensile strength of the 16MND5 steel are decreased, and the creep rupture time is rapidly shortened after thermal aging. The microstructure was analyzed by scanning and transmission electron microscopy (SEM, TEM). 16MND5 steel showed a typical bainitic phase before thermal aging. After 2000 h of thermal aging, the micro-grains were coarsened, and finally changed into a ferritic microstructure. Based on Larson-Miller (LM), Orr-Sherby-Dorn (OSD) parameters methods and Kachanov-Rabotnov (K–R) model to predict uniaxial creep life after thermal aging, the prediction results are satisfactory, and all within the double tolerance band. This work reveals the creep damage mechanism of 16MND5 steel after thermal aging, and provides basic data for the implementation of IVR strategy in nuclear power plants after long-term service. • Characterization of creep behaviors are achieved for 16MND5 steel before and after thermal aging. • Creep failure mechanism of thermal aged 16MND5 steel is explained by microscopic observation. • Influence of thermal aging on macro- and micro-creep failure of 16MND5 steel is understood in depth. • Creep life is well predicted by Larson-Miller and Orr-Sherby-Dorn parameters methods, and validated by experiment. • The K–R model accurately characterizes the three creep stages of thermal aged 16MND5 steel. [ABSTRACT FROM AUTHOR]

Aging is an important risk factor for neurodegenerative diseases. The activation of α7 nicotinic acetylcholine receptor (α7nAChR) is involved in inflammation and cognition, but the specific role it plays in aging remains unknown. This study aimed to investigate the anti-aging effect of the activation of α7nAChR on aging rats and BV2 cells induced by D-galactose, as well as its potential mechanism. D-galactose induced an increase in the SA-β-Gal positive cells, expression of p16 and p21 in vivo and in vitro. α7nAChR selective agonist PNU282987 decreased levels of pro-inflammatory factors, MDA, and Aβ, enhanced SOD activity and levels of anti-inflammatory factor (IL10) in vivo. PNU282987 enhanced the expression of Arg1, decreased the expression of iNOS, IL1β and TNFα in vitro. PNU282987 upregulated the levels of α7nAChR, Nrf2 and HO-1 in vivo and in vitro. The results of Morris water maze and novel object recognition tests showed that PNU282987 improved cognitive impairment in aging rats. Furthermore, α7nAChR selective inhibitor methyllycaconitine (MLA) results were opposite with PNU282987. PNU282987 improves cognitive impairment through inhibiting oxidative stress and neuroinflammation in D-galactose induced aging via regulating the α7nAChR/Nrf2/HO-1 signaling pathway. Therefore, targeting the α7nAChR may be a viable therapeutic approach for anti-inflammaging and neurodegenerative diseases. • D-galactose induces microglial senescence and brain aging. • α7nAChR is downregulated in brain aging and senescent BV2 cells. • The activation of α7nAChR by PNU282987 inhibits oxidative stress and neuroinflammation in vivo and in vitro. • PNU282987 inhibits oxidative stress and neuroinflammation by upregulating the α7nAChR /Nrf2/HO-1 signaling pathway, thereby alleviating cognitive impairment caused by aging. [ABSTRACT FROM AUTHOR]