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Cutting fluids are the most effective method to lower the cutting temperature and decrease the cutting tool wear. At the same time, the cutting fluids influence the corrosion resistance property of the machined surface. In this study, chlorinated paraffin (CP), which is a common additive in the cutting fluid, was selected as the research objective to study its corrosion resistance property. The passivation effect of CP with different concentrations on the machined surface of stainless steel was studied. Electrochemical measurements and surface morphology investigation were used to characterize the passivation effect of CP with different concentrations. The test results showed that the corrosion resistance of stainless steel in the cutting fluid was enhanced with the increase in CP additive. This reason is that the charge transfer resistance increases and the corrosion current density decreases with the increase in CP additive. The X-ray photoelectron spectroscopy (XPS) results show that the proportion of metal oxides on the processed surface of the stainless steel sample was increased from 20.4% to 22.0%, 32.9%, 26.6%, and 31.1% after adding 1 mL, 2 mL, 4 mL and 6 mL CP in the cutting fluid with a total volume of 500 mL, respectively. The oxidation reaction between CP and the stainless steel sample resulted in an increase in metal oxides proportion, which prevented the stainless steel sample from corrosion in cutting fluid.

Intensive and frequent flash droughts pose a threat to the stability of terrestrial ecosystems and affect land carbon sinks, particularly in vulnerable water-limited regions. Here, we evaluated variations in flash drought events in water-limited regions of China from 2001 to 2022 and quantified vegetation resistance (its ability to maintain predrought level) and resilience (its capacity to bounce back from droughts) to flash drought based on solar-induced chlorophyll fluorescence and gross primary productivity. The average frequency of flash droughts was approximately 3.5 events per decade and the duration increased significantly by 3 d during 2001–2022. We found that vegetation resistance to flash drought did not show significant temporal changes, while resilience decreased significantly. Spatially, as aridity increased, vegetation resistance gradually decreased while resilience rose. The strong negative correlation between resistance and resilience demonstrated a trade-off in individual climate regions, which varied among different vegetation types. Among eight vegetation types, evergreen needleleaf forest, evergreen broadleaf forest and mixed forest displayed high-resistance and low-resilience, while deciduous needleleaf forest exhibited both high-resistance and high-resilience. Furthermore, we revealed that aridity index, vapor pressure deficit, and temperature were the most relevant environmental variables for both vegetation resistance and resilience, but had opposite effects and different magnitudes. Our findings highlight that the vulnerability and stability of terrestrial ecosystems are decreasing and are affected by water availability.

Inspired by the increasing use of plasmonic gold and silver nanoplates as probes for diverse analytes, the research community often questions which metal nanoplates should be chosen for a given application. A comparative study was performed on the performance and physicochemical properties of three types of metal nanoplates for use in plasmonic detection of Hg(II) ion. Specifically, gold, silver and Ag@Au nanoplates were studied. The established amalgamation method integrated into a detection scheme using nanoplates affords a unique yet straightforward signaling and extraction route for selective recognition of Hg(II) ion. Upon transformation of Hg(II) ion to metallic mercury, nanoplate amalgamation takes place instantly. This reshapes both the morphology and the optical characteristics of nanoplates. It is found that gold and Ag@Au nanoplates enable highly selective quantitation of Hg(II) ion by using a DNA oligomer consisting of poly-deoxycytidine (poly(C)) as a masking agent against Ag(I) ion. The silver nanoplates, in turn, display the best sensitivity owing to the chemical instability. The induced surface plasmonic shifts (of up to 250 nm and color changes from red to green) allows for determination of Hg(II) over a wide range and with a limit of detection of ~10 nM. It is recommended that the gold and Ag@Au nanoplates are used in relatively complex systems, while silver nanoplates are suited for simple matrices. Graphic abstract The amalgamation process integrated with metal (e.g., Au, Ag and Ag@Au) nanoplates affords plasmonic detection of Hg(II) ion with the aid of a poly(c) DNA sequence as the masking agent for Ag(I) ion.

CBF transcription factors (TFs) are key regulators of plant stress tolerance and play an integral role in plant tolerance to adverse growth environments. However, in the current research situation, there are few reports on the response of the CBF gene to Begonia stress. Therefore, this experiment investigated a novel CBF TF gene, named MbCBF2, which was isolated from M. baccata seedlings. According to the subcellular localization results, the MbCBF2 protein was located in the nucleus. In addition, the expression level of MbCBF2 was higher in new leaves and roots under low-temperature and high-salt induction. After the introduction of MbCBF2 into Arabidopsis thaliana, the adaptability of transgenic A. thaliana to cold and high-salt environments was significantly enhanced. In addition, the high expression of MbCBF2 can also change many physiological indicators in transgenic A. thaliana, such as increased chlorophyll and proline content, superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) activity, and reduced malondialdehyde (MDA) content. Therefore, it can be seen from the above results that MbCBF2 can positively regulate the response of A. thaliana to low-temperature and osmotic stress. In addition, MbCBF2 can also regulate the expression of its downstream genes in transgenic lines. It can not only positively regulate the expression of the downstream key genes AtCOR15a, AtERD10, AtRD29a/b and AtCOR6.6/47, related to cold stress at low temperatures, but can also positively regulate the expression of the downstream key genes AtNCED3, AtCAT1, AtP5CS, AtPIF1/4 and AtSnRK2.4, related to salt stress. That is, the overexpression of the MbCBF2 gene further improved the adaptability and tolerance of transgenic plants to low-temperature and high-salt environments.

As natural backwater structures, landslide dams both threaten downstream human settlement or infrastructure and contain abundant hydro-energy and tourism resources, so research on their development feasibility is of great significance for permanently remedying them and effectively turning disasters into benefits. Through an analysis of the factors influencing landslide dam development and utilization, an index system (consisting of target, rule, and index layers) for evaluating development feasibility was constructed in this paper. Considering uncertainty and randomness in development feasibility evaluation, a cloud model-improved evaluation method was proposed to determine membership and score clouds based on the uncertainty reasoning of cloud model, and a cloud model-improved analytic hierarchy process (AHP-Cloud Model) was introduced to obtain weights. Final evaluation results were obtained using a hierarchical weighted summary. The improved method was applied to evaluate the Hongshiyan and Tangjiashan landslide dams and the results were compared with the maximum membership principle results. The results showed that the cloud model depicted the fuzziness and uncertainty in the evaluation process. The improved method proposed in this paper overcame the loss of fuzziness in the maximum membership principle evaluation results, and was capable of more directly presenting evaluation results. The development feasibility of the Hongshiyan landslide dam was relatively high, while that of the Tangjiashan landslide dam was relatively low. As suggested by these results, the evaluation model proposed in this paper has great significance for preparing a long-term management scheme for landslide dams.

In recent years, debris flows have frequently erupted in the narrow-steep gully of the earthquake-hit Wenchuan region, displaying high flow velocities and powerful scouring abilities. However, few scouring studies in the narrow-steep gully have been conducted. A model experiment simulated the debris flow scouring process in a narrow-steep flume, in which several important physical parameters, including the debris flow density ( ρ ), flume slope ( θ ), and grain size of the sediment ( D ), were varied to investigate their influences on the erodible strength. The experimental flows were composed of 50 L of water and grains, which scoured 2.3 m of erodible bed down a steeply inclined flume. A high-speed camera photographed the scouring processes, while a 3D laser device captured the final bed shapes. The experiments show that the debris flow first collides with the sediment at the head of the gully to form a pit, which is enlarged by continuous impact; the velocity of the debris flow out of the pit is significantly reduced due to the change in flow direction, resulting in a much lesser scouring effect after the pit; and finally, the gully bed presents the shape of a pit at the entrance and a groove in the middle and rear. The critical scour slope, where the gully bed shows scouring, increases with increasing debris flow density but decreases with increasing grain size of sediment. Following scouring, the maximum scouring depth is further positively correlated with the flume slope. In narrow-steep gullies, the gully bed is extremely susceptible to scouring by debris flow with a low density, and even headward erosion appears, at which the maximum scouring depth only increased from 148.04 to 149.97 mm, but the erosion amount had a significant increase of 36.9%. The research results have an important significance for revealing the disaster-causing phenomena and mechanisms of debris flows in the narrow-steep gully.

In the natural environment, plants often face unfavorable factors such as drought, cold, and freezing, which affect their growth and yield. The MYB (v-myb avian myeloblastosis viral oncogene homolog) transcription factor family is widely involved in plant responses to biotic and abiotic stresses. In this study, Malus baccata (L.) Borkh was used as the research material, and a gene MbMYB4 of the MYB family was cloned from it. The open reading frame (ORF) of MbMYB4 was found to be 762 bp, encoding 253 amino acids; sequence alignment results and predictions of the protein structure indicated that the MbMYB4 protein contained the conserved MYB domain. Subcellular localization showed that MbMYB4 was localized in the nucleus. In addition, the use of quantitative real-time PCR (qPCR) technology found that the expression of MbMYB4 was enriched in the young leaf and root, and it was highly affected by cold and drought treatments in M. baccata seedlings. When MbMYB4 was introduced into Arabidopsis thaliana, it greatly increased the cold and drought tolerance in the transgenic plant. Under cold and drought stresses, the proline and chlorophyll content, and peroxidase (POD) and catalase (CAT) activities of transgenic A. thaliana increased significantly, and the content of malondialdehyde (MDA) and the relative conductivity decreased significantly, indicating that the plasma membrane damage of transgenic A. thaliana was lesser. Therefore, the overexpression of the MbMYB4 gene in A. thaliana can enhance the tolerance of transgenic plants to cold and drought stresses.

Teosinte, the wild ancestor of maize ( Zea mays subsp . mays ), has three times the seed protein content of most modern inbreds and hybrids, but the mechanisms that are responsible for this trait are unknown 1 , 2 . Here we use trio binning to create a contiguous haplotype DNA sequence of a teosinte ( Zea mays subsp . parviglumis ) and, through map-based cloning, identify a major high-protein quantitative trait locus, TEOSINTE HIGH PROTEIN 9 ( THP9 ), on chromosome 9. THP9 encodes an asparagine synthetase 4 enzyme that is highly expressed in teosinte, but not in the B73 inbred, in which a deletion in the tenth intron of THP9-B73 causes incorrect splicing of THP9-B73 transcripts. Transgenic expression of THP9-teosinte in B73 significantly increased the seed protein content. Introgression of THP9-teosinte into modern maize inbreds and hybrids greatly enhanced the accumulation of free amino acids, especially asparagine, throughout the plant, and increased seed protein content without affecting yield. THP9-teosinte seems to increase nitrogen-use efficiency, which is important for promoting a high yield under low-nitrogen conditions. Genetic analyses of teosinte, the wild ancestor of maize, identify a locus ( THP9 ) that is associated with high seed protein content and increased nitrogen-use efficiency, suggesting that THP9 could have applications in crop breeding.

Grazing cuts N 2 O emission Levels of the greenhouse gas nitrous oxide have increased since pre-industrial times, mainly because of agricultural activities. Among these changes it has been reported that livestock grazing substantially increases nitrous oxide emissions from temperate grasslands. New data obtained from year-round monitoring at ten steppe grassland sites in Inner Mongolia, China, challenge this view by highlighting a previously overlooked interaction. The measurements made using the automatic chamber system show that nitrous oxide release is dominated by pulses during springtime thawing, is highest in ungrazed steppe and decreases with increasing stocking rate. So surprisingly, grazing decreases rather than increases nitrous oxide emissions by changing the soil water balance and microbial activity. To examine the effect of increased livestock numbers on nitrous oxide emissions the authors report year-round nitrous oxide flux measurements at ten steppe grassland sites in Inner Mongolia. They find that nitrous oxide emission is much higher during spring thaw and is highest in ungrazed steppe, decreasing with increasing stocking rate, which suggests that grazing decreases rather than increases nitrous oxide emissions. Atmospheric concentrations of the greenhouse gas nitrous oxide (N 2 O) have increased significantly since pre-industrial times owing to anthropogenic perturbation of the global nitrogen cycle 1 , 2 , with animal production being one of the main contributors 3 . Grasslands cover about 20 per cent of the temperate land surface of the Earth and are widely used as pasture. It has been suggested that high animal stocking rates and the resulting elevated nitrogen input increase N 2 O emissions 4 , 5 , 6 , 7 . Internationally agreed methods to upscale the effect of increased livestock numbers on N 2 O emissions are based directly on per capita nitrogen inputs 8 . However, measurements of grassland N 2 O fluxes are often performed over short time periods 9 , with low time resolution and mostly during the growing season. In consequence, our understanding of the daily and seasonal dynamics of grassland N 2 O fluxes remains limited. Here we report year-round N 2 O flux measurements with high and low temporal resolution at ten steppe grassland sites in Inner Mongolia, China. We show that short-lived pulses of N 2 O emission during spring thaw dominate the annual N 2 O budget at our study sites. The N 2 O emission pulses are highest in ungrazed steppe and decrease with increasing stocking rate, suggesting that grazing decreases rather than increases N 2 O emissions. Our results show that the stimulatory effect of higher stocking rates on nitrogen cycling 4 , 7 and, hence, on N 2 O emission is more than offset by the effects of a parallel reduction in microbial biomass, inorganic nitrogen production and wintertime water retention. By neglecting these freeze–thaw interactions, existing approaches may have systematically overestimated N 2 O emissions over the last century for semi-arid, cool temperate grasslands by up to 72 per cent.

The MYB transcription factor (TF) family is one of the largest transcription families in plants, which is widely involved in the responses of plants to biotic and abiotic stresses, as well as plant growth, development, and metabolic regulation. In the present study, a new MYB TF gene, MbMYB108, from Malus baccata (L.) Borkh, was identified and characterized. The open reading frame (ORF) of MbMYB108 was found to be 903 bp, encoding 300 amino acids. Sequence alignment results and predictions of the protein structure indicated that the MbMYB108 protein contained the conserved MYB domain. Subcellular localization showed that MbMYB108 was localized to the nucleus. The expression of MbMYB108 was enriched in young and mature leaves, and was highly affected by cold and drought treatments in M. baccata seedlings. When MbMYB108 was introduced into Arabidopsis thaliana, it greatly increased the cold and drought tolerances in the transgenic plant. Increased expression of MbMYB108 in transgenic A. thaliana also resulted in higher activities of peroxidase (POD) and catalase (CAT), higher contents of proline and chlorophyll, while malondialdehyde (MDA) content and relative conductivity were lower, especially in response to cold and drought stresses. Therefore, these results suggest that MbMYB108 probably plays an important role in the response to cold and drought stresses in A. thaliana by enhancing the scavenging capability for reactive oxygen species (ROS).