Research into CUP-VISAR velocity reconstruction based on weighted DRUNet and total variation joint optimization.

This Letter proposes a CUP-VISAR data reconstruction algorithm for laser-driven inertial confinement fusion (ICF) research. The algorithm combines weighted deep residual U-Net (DRUNet) and joint optimization with total variation (TV) to improve shockwave velocity fringe image reconstruction. The simulation results demonstrate that the proposed algorithm outperforms the ADMM-TV and enhanced 3D total variation (E-3DTV) algorithms, enhancing the quality of the reconstructed images and thereby improving the accuracy of velocity field calculations. Furthermore, it addresses the challenges of the high compression ratio caused by the diagnostic requirements of the larger number of sampling frames in the CUP-VISAR system and the issues of aliasing within a large encoding aperture. The proposed algorithm demonstrates good robustness to noise, ensuring reliable reconstruction even under Gaussian noise with a relative intensity of 0.05. This algorithm contributes to ICF diagnostics in complex environmental conditions and has theoretical significance and practical application value for achieving controlled thermonuclear fusion.

First Report of Southern Blight Caused by Athelia rolfsii on Pepper in Yiyang, China.

Pepper(Capsicum annuum L.) is the vegetable with the largest production area China (Zou and Zou 2021). In the summer of 2020 and 2021, disease symptoms were observed in C. annuum L. cv. bola in a 10-ha field in Yiyang(28.35°N, 112.56°E), Hunan province of China. The disease incidence ranged from 10% to 30%. The symptoms initially appeared as tan lesions, which were colonized by fast-growing white mycelia, at the soil line. Affected plants eventually became wilted. Wilting was accompanied by girdling of the stem at the base, and signs of the pathogen, mycelia and golden-brown colored sclerotia. The spatial distribution of the disease was either single plants or small foci of affected plants. Diseased stem sections (1.0~1.5 cm) of 20 plants from the field in 2021 with typical symptoms were surface sterilized with 75% ethanol for 30 s, followed by 60 s in 2.5% NaClO, rinsed thrice with sterile water, air dried and plated on potato dextrose agar (PDA), and incubated at 28℃ in the dark for 5 days to isolate the causative pathogen. Twenty fungal isolates with similar colony morphology were collected and purified. These isolates formed radial colonies, and abundant sclerotia were observed after 5 to 10 days of incubation at 28℃. The color of the sclerotia with a diameter of 1.39 ± 0.15 mm (1.15 to 1.60, n=50) gradually changed from white to light yellow, and finally to dark brown. The representative isolate YYBJ20 was selected for further molecular identification. The internal transcribed spacer region and elongation factor-1alpha gene were amplified using the primers, ITS1/ITS4 (White et al. 1990) and EF1-983F/EF1-2218R (Rehner and Buckley 2005), respectively. The ITS and EF1α amplicons were sequenced and deposited in GenBank with the accession numbers OQ186649 and OQ221158, respectively. Sequence analysis revealed that the ITS and EF1α sequences of the YYBJ20 isolate exhibited ≥99% of identity with the ITS (MH260413 and AB075300) and EF1α (OL416131 and MW322687) sequences of Athelia rolfsii, respectively. Phylogenetic analysis classified YYBJ20 into a common clade with different A. rolfsii strains, but different from other Athelia or Sclerotium species. For pathogenicity tests, PDA plugs (6 mm diam.) colonized by 3-day-old mycelia were inoculated into the stem bases of 30-day-old pepper seedlings (n=10). Another 10 seedlings were inoculated with noncolonized PDA plugs were used as noninoculated controls. The pepper seedlings were incubated at 28 ± 2℃ and 60 to 80 % relative humidity under a 14h-10h of light-dark cycle. After 10 days of incubation, ten YYBJ20-inoculated plants were wilted with similar symptoms to those observed in the field, while control plants remained healthy. The pathogenicity tests were repeated three times. The fungal strain re-isolated from the infected seedlings (100% re-isolation frequency) showed the same morphological and molecular traits as the original isolates from the diseased plants. No fungi were isolated from the control plants, which is consistent with the Koch's postulates. Based on the morphological and sequencing results, the causative fungus was identified as A. rolfsii (anamorph Sclerotium rolfsii). To our knowledge, this is the first report of A. rolfsii causing southern blight on pepper in China. Due to the broad host range of and serious consequences caused by A. rolfsii (Lei et al. 2021; Zhang et al. 2022; Zhu et al. 2022), this research will be beneficial to develop strategies to mitigate future losses of pepper in China.

First report of Agroathelia rolfsii causing southern blight on cowpea in China.

Cowpea (Vigna unguiculata L.) is a legume consumed as a high-quality plant protein source in many parts of the world. In August 2023, it was observed that a plant disease affected cowpea growth in Yiyang (28.34°N, 112.55°E), China. The average disease incidence was 10%, resulting in 8.5% economic losses in approximately 3,000 m2. The symptoms initially appeared as brown lesions near the stem-soil interface and the lesions were colonized by white mycelia. As the disease progressed, the disease symptoms included constriction and brown staining at the base of the stem, covered with a small amount of white mycelia. Eventually, the entire plants withered and collapsed and many sclerotia were scattered on the ground around the diseased stem. Twenty samples (10 sclerotia and 10 diseased tissue fragments) were collected from symptomatic plants for causal agent isolation. Samples were disinfected with 70% ethanol for 30 s, 5% NaClO for 1 min, rinsed three times with sterile water, dried and placed on potato dextrose agar (PDA) plates at 28℃ in the dark. In total, 20 isolates were obtained by the hyphal tip method (Terrones et al. 2022) and showed a consistent phenotype of white cottony mycelia on PDA with an growth rate of 12.9 to 21.3 mm/day (n = 20). Sclerotia formed at five to eight days post inoculation, were initially whitish, turning beige and eventually dark brown. The diameter of mature sclerotia ranged from 0.89 to 2.13 mm (mean = 1.64±0.29 mm; n =50). For pathogen identification, ITS1/ITS4 (White et al. 1990) and EF1-983F/EF1-2218R (Rehner and Buckley 2005) primers were used to amplify the internal transcribed spacer regions (ITS) and translation elongation factor-1 alpha gene (TEF-1α), respectively. The sequences of all 20 isolates showed 99% to 100% similarity with Agroathelia rolfsii sequences from GenBank by BLAST analysis. The sequences of two representative strains, ID1 and ID4, were deposited in GenBank. The ITS sequences of ID1 (OR689482) and ID4 (OR689481) were ＞99% similar to A. rolfsii strain QJ7 (593/596 bp; MZ750983) and A. rolfsii strain Kale078 (565/568 bp; MN872304), respectively. Also, TEF-1α sequences of ID1 (OR713735) and ID4 (OR713736) were ＞99% similar to the sequences of A. rolfsii strain HS-Sr (1073/1073 bp; OL416131) and A. rolfsii strain MSB1-2 (1070/1075 bp; MN702790), respectively. Phylogenetic analysis based on ITS and TEF1-α sequences indicated that ID1 and ID4 clustered into the A. rolfsii clade. Based on morphology and sequence analyses, the isolates ID1 and ID4 were identified as A. rolfsii (anamorph Sclerotium rolfsii). Pathogenicity tests were conducted three times on healthy 30-day-old cowpea seedlings. Five plants were inoculated with 6-day-old mycelial discs (6 mm) of ID1 or ID4 at the base of the seedlings (n = 30) while four plants were inoculated with a sterile PDA disc as a control (n = 12). All seedlings were cultivated in a greenhouse with a temperature of 26°C to 28°C and relative humidity 60% to 80% with a 14/10 h light/dark photoperiod. Eight days later, all the fungal inoculated seedlings showed symptoms including brown necrosis and collapse of the stems, and eventual withering of the seedlings. Control plants remained asymptomatic. The causal pathogens were reisolated in PDA plates and identified by ITS sequence analysis, completing Koch's postulates. To our knowledge, this is the first report of A. rolfsii causing southern blight on cowpea in China. Early accurate diagnosis will help farmers to adopt suitable practices to control disease outbreaks and reduce losses.

Impacts of land use/cover and slope on the spatial distribution and ecological risk of trace metals in soils affected by smelting emissions.

The soil contamination around smelting sites shows high spatial heterogeneity. This study investigated the impacts of distance, land use/cover types, land slopes, wind direction, and soil properties on the distribution and ecological risk of trace metals in the soil around a copper smelter. The results demonstrated that the average concentrations of As, Cd, Cu, Pb, and Zn were 248.0, 16.8, 502.4, 885.6, and 250.2 g mg kg-1, respectively, higher than their background values. The hotspots of trace metals were primarily distributed in the soil of smelting production areas, runoff pollution areas, and areas in the dominant wind direction. The concentrations of trace metals decreased with the distance to the smelting production area. An exponential decay regression revealed that, depending on the metal species, the influence distances of smelting emissions on trace metals in soil ranged from 450 to 1000 m. Land use/cover types and land slopes significantly affected trace element concentrations in the soil around the smelter. High concentrations of trace metals were observed in farmland, grassland, and flatland areas. The average concentrations of trace metals in the soil decreased in the order of flat land > gentle slope > steep slope. Soil pH values were significantly positively correlated with Cd, Cu, Pb, Zn, and As, and SOM was significantly positively correlated with Cd, Pb, and Zn in the soil. Trace metals in the soil of the study area posed a significant ecological risk. The primary factors influencing the distribution of ecological risk, as determined by the Ctree analysis, were land slope, soil pH, and distance to the source. These results can support the rapid identification of high-risk sites and facilitate risk prevention and control around smelting sites.

Release characteristics of heavy metals from electrolytic manganese residue under varying environmental factors.

High levels of manganese (Mn) and other heavy metals from electrolytic manganese residue (EMR) stockpiled would be released into the environment under natural conditions. A batch-leaching test was carried out to investigate the release characteristics of heavy metals from EMR with different storage times under simulated environmental conditions such as acid rain with different pH (3.0, 4.5, 5.6, and 7.0) at contact times of 1, 2, 4, 6, and 12 h; liquid to solid ratio (L/S) (5:1, 10:1, 20:1, and 30:1); and temperature (15, 25, 35, and 45 °C). The results showed that low pH (3.0 and 4.5) and high temperature (35 and 45 °C) could significantly promote heavy metal leaching from EMRs and increasing the L/S ratio above 20:1 mL/g significantly decreased heavy metal leachate concentrations due to dilution effect. Cr, Mn, and Pb concentrations in leachate increased almost continuously throughout the leaching process, while Zn decreased slightly at the 12th hour. Meanwhile, heavy metal concentrations in EMR1 (fresh EMR) were higher than in EMR2 (out stockpiled for more than 3 months). The concentrations of Mn, Pb, and Zn in leachates from EMRs at pH 3.0 and 4.5 leaching far exceeded the allowable maximum discharge concentrations for pollutants of the integrated wastewater discharge standard in China (GB8978-1996) by 57.5-59.0, 1.3-4.3, and 1.1-1.8 and 53.5-56.0, 3.04-7.25, and 1.0-1.91 times, respectively. Additionally, the Mn concentrations from both EMR leachates at pH 7.0 were above the national safe emission threshold. The morphological structure of EMRs changed after leaching, and XRD analysis showed the disappearance of MnO2, SiO2, FeS2, and CaSO4. The XPS revealed that Cr, Mn, Pb, and Zn existed as Cr3+, MnO, PbSO4, and ZnSiO3, respectively, after leaching. The study concluded that Mn, Pb, and Zn from EMRS leached by acid rain might pose a high potential environmental risk. Therefore, developing appropriate disposal techniques for EMR is necessary to prevent heavy metal pollution.

Effects of Simulated Reclaimed Water on Soil Particle Sizes and Cd Adsorption and Migration in Soils at Smelting Sites.

This work studied the vertical migration characteristics of Cd in soil profiles from a zinc smelting site under the influence of simulated reclaimed water containing NaCl and Na2SO4. The isothermal adsorption curves of Cd in the soils of miscellaneous fill and weathered slate well fitted the Freundlich and Langmuir models, with R2 ranging from 0.991 to 0.998. The maximum adsorption capacity of Cd in the soils decreased significantly under the salt ion treatments with NaCl and Na2SO4. After leaching, the Cd concentrations in the leachates and Cd contents in the subsoil layers of 10-60 cm followed the order NaCl treatment > Na2SO4 treatment > CK (p < 0.05), suggesting that the salt ions promoted the vertical migration of exogenous Cd. The proportion of coarse particles (> 0.02 mm) decreased, while that of fine particles (< 0.02 mm) increased under salt ion treatments (p < 0.05). The morphological characterization indicated that salt ions accelerated the erosion and fragmentation of coarse particles to form fine particles. The use of reclaimed water to flush smelting sites may increase the risk of Cd migration with small-sized soil particles from the soil to groundwater.

Spatial heterogeneity and source apportionment of soil metal(loid)s in an abandoned lead/zinc smelter.

Metal smelting have brought severe metal(loid)s contamination to the soil. Spatial distribution and pollution source analysis for soil metal(loid)s in an abandoned lead/zinc smelter were studied. The results showed that soil was contaminated heavily with metal(loid)s. The mean of lead (Pb), arsenic (As), cadmium (Cd), mercury (Hg) and antimony (Sb) content in topsoil is 9.7, 8.2, 5.0, 2.3, and 1.2 times higher than the risk screening value for soil contamination of development land of China (GB36600-2018), respectively. Cd is mainly enriched in the 0-6 m depth of site soil while As and Pb mainly deposited in the 0-4 m layer. The spatial distribution of soil metal(loid)s is significantly correlated with the pollution source in the different functional areas of smelter. As, Hg, Sb, Pb and copper (Cu) were mainly distributed in pyrometallurgical area, while Cd, thallium (Tl) and zinc (Zn) was mainly existed in both hydrometallurgical area and raw material storage area. Soil metal(loid)s pollution sources in the abandoned smelter are mainly contributed to the anthropogenic sources, accounting for 84.5%. Specifically, Pb, Tl, As, Hg, Sb and Cu mainly from atmospheric deposition (55.9%), Cd and Zn mainly from surface runoff (28.6%), While nickel (Ni) mainly comes from parent material (15.5%). The results clarified the spatial distribution and their sources in different functional areas of the smelter, providing a new thought for the risk prevention and control of metal(loid)s in polluted site soil.

Comparative genomic analysis of Citrobacter sp. XT1-2-2 reveals insights into the molecular mechanism of microbial immobilization of heavy metals.

BACKGROUND: In our previous study, Citrobacter sp. XT1-2-2 was isolated from high cadmium-contaminated soils, and demonstrated an excellent ability to decrease the bioavailability of cadmium in the soil and inhibit cadmium uptake in rice. In addition, the strain XT1-2-2 could significantly promote rice growth and increase rice biomass. Therefore, the strain XT1-2-2 shows great potential for remediation of cadmium -contaminated soils. However, the genome sequence of this organism has not been reported so far.  RESULTS: Here the basic characteristics and genetic diversity of the strain XT1-2-2 were described, together with the draft genome and comparative genomic results. The strain XT1-2-2 is 5040459 bp long with an average G + C content of 52.09%, and contains a total of 4801 genes. Putative genomic islands were predicted in the genome of Citrobacter sp. XT1-2-2. All genes of a complete set of sulfate reduction pathway and various putative heavy metal resistance genes in the genome were identified and analyzed. CONCLUSIONS: These analytical results provide insights into the genomic basis of microbial immobilization of heavy metals.

The impact of anti-COVID-19 nonpharmaceutical interventions on hand, foot, and mouth disease-A spatiotemporal perspective in Xi'an, northwestern China.

Growing evidence has shown that anti-COVID-19 nonpharmaceutical interventions (NPIs) can support prevention and control of various infectious diseases, including intestinal diseases. However, most studies focused on the short-term mitigating impact and neglected the dynamic impact over time. This study is aimed to investigate the dynamic impact of anti-COVID-19 NPIs on hand, foot, and mouth disease (HFMD) over time in Xi'an City, northwestern China. Based on the surveillance data of HFMD, meteorological and web search data, Bayesian Structural Time Series model and interrupted time series analysis were performed to quantitatively measure the impact of NPIs in sequent phases with different intensities and to predict the counterfactual number of HFMD cases. From 2013 to 2021, a total number of 172,898 HFMD cases were reported in Xi'an. In 2020, there appeared a significant decrease in HFMD incidence (-94.52%, 95% CI: -97.54% to -81.95%) in the first half of the year and the peak period shifted from June to October by a small margin of 6.74% compared to the previous years of 2013 to 2019. In 2021, the seasonality of HFMD incidence gradually returned to the bimodal temporal variation pattern with a significant average decline of 61.09%. In particular, the impact of NPIs on HFMD was more evident among young children (0-3 years), and the HFMD incidence reported in industrial areas had an unexpected increase of 51.71% in 2020 autumn and winter. Results suggested that both direct and indirect NPIs should be implemented as effective public health measures to reduce infectious disease and improve surveillance strategies, and HFMD incidence in Xi'an experienced a significant rebound to the previous seasonality after a prominent decline influenced by the anti-COVID-19 NPIs.

Cellulose filter paper immobilized α-glucosidase and its application to screening inhibitors from traditional Chinese medicine.

In this study, α-glucosidase was successfully immobilized on cellulose filter paper and further applied to screening inhibitors from traditional Chinese medicines combined with capillary electrophoresis analysis. For α-glucosidase immobilization, a cellulose filter paper was used as the carrier and grafted with amino groups by coating chitosan, then α-glucosidase was covalently bonded on the amino-modified carrier via epoxy ring-opening reaction using polyethylene glycol diglycidyl ether as the crosslinker. Several parameters influencing the enzyme immobilization were optimized and the optimal values were enzyme concentration of 4 U/mL, polyethylene glycol diglycidyl ether concentration of 1.25%, chitosan concentration of 7.5 mg/mL, immobilization pH 7.0, crosslinking time of 4 h and immobilization time of 2 h. The immobilized α-glucosidase exhibited good batch-to-batch reproducibility (RSD = 2.1%, n = 5), excellent storage stability (73.5% of its initial activity after being stored at 4°C for 15 days), and reusability (75% of its initial activity after 10 repeated cycles). The Michaelis constant of immobilized α-glucosidase and half-maximal inhibitory concentration of acarbose were calculated to be 1.12 mM and 0.38 µM, respectively. Finally, the immobilized α-glucosidase was used for screening inhibitors from 14 kinds of Traditional Chinese Medicine extracts, and Sanguisorbae Radix showed the strongest inhibitory effect on α-glucosidase.

Screening of acetylcholinesterase inhibitory and antioxidant active compounds from Terminalia chebula fruits by spectrum-effect relationship and liquid chromatography-mass spectrometry analysis.

Screening and identification of active components from traditional Chinese medicines is rather challenging due to the diversity and complexity of chemical components. Herein, a comprehensive strategy based on a spectrum-effect relationship model and LC-MS analysis was developed to screen active components from Terminalia chebula fruits. The water extract of T. chebula fruits was subjected to macroporous resin column and then eluted successively with water and 30%, 50%, 70%, and 95% ethanol. The 30% ethanol eluate fractions of eighteen batches from T. chebula fruits were used for the spectrum-effect relationship study. The IC50 values for acetylcholinesterase inhibitory and 2,2-diphenyl-1-picrylhydrazyl scavenging activities were measured, LC fingerprints were established, and 15 common peaks were specified. The spectrum-effect relationship between common peaks and IC50 values was investigated by principal component analysis, gray relational analysis, partial least square and multiple linear regression. The 30% ethanol eluate fraction was further characterized by LC-MS analysis. The chromatographic peaks (Peaks 1, 2, 3, 5, 12, 14, 15) making great contributions to the efficacy were screened through a spectrum-effect relationship model, and sixteen components were further identified. The results suggested that the proposed strategy is simple and effective for acquiring active components from a complex matrix.

α-Glucosidase inhibitors screening from Cyclocarya paliurus based on spectrum-effect relationship and UPLC-MS/MS.

Cyclocarya paliurus is an edible and medicinal plant exhibiting significant hypoglycemic effect. However, its active components are still unclear and need further elucidation. In this research, the active components of the leaves of C. paliurus responsible for the α-glucosidase inhibitory activity were screened and identified based on a spectrum-effect relationship study in combination with ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) analysis. The 70% ethanol eluate fraction of the leaves of C. paliurus with the strongest α-glucosidase inhibitory activity was obtained after extraction and purification with macroporous resin. Their chromatographic fingerprints (15 batches) were established by UPLC analysis and 32 common peaks were specified by similarity analysis. Their IC50 values for α-glucosidase inhibition were measured by an enzymatic reaction. Several multivariate statistical analysis methods including hierarchical cluster analysis, principal component analysis, partial least square analysis and gray relational analysis were applied to explore the spectrum-effect relationship between common peaks and IC50 values, and the chromatographic peaks making a large contribution to efficacy were screened out. To further elucidate the active components of leaves of C. paliurus, the 70% ethanol eluate fraction was characterized by UPLC-MS/MS analysis, and 10 compounds were identified. This study provides a valuable reference for further research and development of hypoglycemic active components of C. paliurus.

Tolerance capacities of Broussonetia papyrifera to heavy metal(loid)s and its phytoremediation potential of the contaminated soil.

Broussonetia papyrifera, is a promising fast-growing woody plant for the phytoremediation of heavy metal(loid) (HM)-contaminated soil. In this study, a greenhouse experiment was conducted to explore the tolerance capacities of B. papyrifera and its phytoremediation potential in the HM-contaminated soil. The results indicated that B. papyrifera could effectively decrease malondialdehyde (MDA) content by enhancing the antioxidant enzyme activities along with the cultivation in the HM-contaminated soil. Significant (p < 0.05) negative relationships were found between MDA content and superoxide dismutase (r = -0.620) and catalase activities (r = -0.702) in B. papyrifera leaves. Fourier Transform Infrared Spectroscopy analysis indicated that the main functional groups in B. papyrifera roots were slightly influenced by HMs, and organic acids, carbohydrates, protein, and amino acids might bind with HMs in plant roots to alleviate the adverse effect of HMs on plants growth. Meanwhile, B. papyrifera had great potential used for the phytoextraction of Cd and Zn in HM-contaminated soil. The maximum total Cd and Zn accumulation amount in B. papyrifera shoots could attach to 2.26 and 66.8 mg·pot-1, respectively. These observations suggested that B. papyrifera has large biomass and high tolerance to HMs, which can be regarded as a promising plant for the eco-remediation of HM-contaminated sites.Novelty statement In this study, a fast-growing woody plant, Broussonetia papyrifera, was used for heavy metal(loid) (HM)-contaminated soil remediation. We found that B. papyrifera can effectively alleviate the adverse effect of HMs on plant growth by enhancing the antioxidant enzyme activities in leaves and binding HMs with organic acids, carbohydrates, protein, and amino acids in roots. Furthermore, the maximum total Cd and Zn accumulation amount in B. papyrifera shoots could attach to 2.26 and 66.8 mg·pot-1, which suggested that B. papyrifera might be regarded as a promising woody plant used for the phytoextraction of Cd and Zn in the contaminated soil.

Effects of combined soil amendments on Cd accumulation, translocation and food safety in rice: a field study in southern China.

Excessive Cd content and high Cd/Zn ratio in rice grains threaten human health. To study the reduction effects of combined soil amendments on Cd content and Cd/Zn ratio in rice planting in soils with different Cd contamination levels, we conducted field trials in three regions of Hunan province, China. Six field treatments were designed in each study area, including control (CK), lime alone (L), lime combined with sepiolite (LS), phosphate fertilizer (LP), organic fertilizer (LO) and phosphate fertilizer + organic fertilizer (LPO). The application of the combined amendments reduced the Cd content in rice grains to less than the Food Health Standard of China (0.2 mg/kg) and the Cd/Zn ratio to less than the safety threshold of 0.015. The average reduction rates of grain Cd content under the combined treatments among the three regions increased with the increase in Cd content in the soil. Meanwhile, the amendments also decreased the soil available Cd and Zn concentration significantly. The LO had the highest efficiency on decreasing Cd content in rice grains among these amendments, which is ranged from 44.6% to 52.8% in the three regions compared with CK. Similarly, high reduction rates of Cd/Zn ratio were found in the LO treatment, with an average value of 57.3% among the three regions. The grain Cd contents and Cd/Zn ratios were significantly correlated with the soil available Cd concentrations, plant uptake factor and the straw to rice grain translocation factor (TFgs) (P < 0.05). The results indicated that the combined soil amendments, especially lime combined with organic fertilizer, would be an effective way to control Cd content in rice.

Adsorption of Cd on Soils with Various Particle Sizes from an Abandoned Non-ferrous Smelting Site: Characteristics and Mechanism.

Soil particle size could intensively impact the Cd adsorption in soils. The adsorption characteristics of Cd on miscellaneous fill (MF) and weathered slate (WS), collected from a zinc smelting site, were studied by batch experiments under conditions of different initial Cd concentrations and soil particle sizes. The results showed that the adsorption kinetics of Cd for soil particles from MF and WS were well fitted with the pseudo-first-order model, and the Cd adsorption isotherms well conformed to the Freundlich model. Soil particle size had an inconspicuous influence on adsorption rate, while the adsorption capacity decreased with particle size increase. The Cd adsorption on soil particles could be due to the exchange with Fe/Al, and -OH/C=O sites were the predominant adsorption sites. The MF may cause secondary pollution risk due to its low adsorption ability for Cd in smelting sites.

Combined amendment reduces soil Cd availability and rice Cd accumulation in three consecutive rice planting seasons.

The scientific application of stabilized materials has been considered an effective method for the in situ remediation of Cd-contaminated soil. This study aimed to investigate the persistence of the effect of a combined amendment of limestone and sepiolite (LS) on soil Cd availability and accumulation in rice grown in a mildly Cd-contaminated paddy field (0.45 mg/kg of Cd) over three consecutive rice seasons. 1125-4500 kg/ha of LS was applied to the soil before the first rice planting season and 562.5-2250 kg/ha of LS was supplemented before the third rice planting season. The application of LS (1125-4500 kg/ha) increased the soil pH by 0.44-1.09, 0.18-0.53, and 0.42-0.68 in the first, second, and third season, respectively, and decreased the soil acid-extractable Cd content by 18.2-36.4%, 17.7-33.5%, and 9.6-17.6%. LS application significantly decreased the Cd contents in the rice tissues. The application of 4500 kg/ha of LS decreased the Cd content in brown rice to below the National Food Limit Standard of 0.2 mg/kg (GB 2762-2017) in the three consecutive rice seasons. However, the effect of LS on the soil-rice system was significantly weakened in the third season. The supplementary application of 562.5-2250 kg/ha of LS further decreased the Cd content in brown rice by 26.1-56.5% and decreased the health risk index by 23.7-43.8%. Therefore, it was recommended to apply 4500 kg/ha of LS in the first season and to supplement 2250 kg/ha of LS in the third season to effectively guarantee the clean production of rice in three consecutive rice seasons.

Physiological responses, tolerance efficiency, and phytoextraction potential of Hylotelephium spectabile (Boreau) H. Ohba under Cd stress in hydroponic condition.

A sand hydroponic experiment with different concentrations of 0, 5, 10, 20, 40 mg L-1 Cd was used to study the growth and physiological response of Hylotelephium spectabile (Boreau) H. Ohba. and its phytoextraction potential for Cd. The results showed that total plant biomass under 5 mg L-1 Cd treatment was slightly affected. The content of malondialdehyde (MDA) in leaf exposed to Cd was higher, and the POD and CAT activity exhibited a positive response to the low level of Cd addition (5 mg·L-1). The photosynthesis pigments were slightly inhibited, and the ultrastructure of chloroplast remained intact after treatment with 10 mg L-1 Cd. The maximum leaf Cd content (603 mg·kg-1) was found in 5 mg L-1 Cd treatment, then decreased with the Cd level increased. The maximum Cd content in the shoots far exceeds the threshold level (100 mg kg-1) for a Cd-hyperaccumulator plant with the value of translocation factor (TFshoot/root) for Cd reaching up to 5.62. In conclusion, H. spectabile showed normal growth and physiological response and high shoot Cd accumulation under 5 mg L-1 Cd stress, which made it to be a good candidate for phytoextraction of low-level Cd polluted environment.

Cleanup of arsenic, cadmium, and lead in the soil from a smelting site using N,N-bis(carboxymethyl)-L-glutamic acid combined with ascorbic acid: A lab-scale experiment.

Chemical washing has been carried out to remediate soil contaminated with heavy metals. In this study, the appropriate washing conditions for N,N-bis(carboxymethyl)-L-glutamic acid (GLDA) combined with ascorbic acid were determined to remove As, Cd, and Pb in the soil from the smelting site. The mechanism of heavy metal removal by the washing agent was also clarified. The results showed that heavy metals in the soil from the smelting site can be effectively removed. The removal percentages of As, Cd, and Pb in the soil from the smelting site were found to be 34.49%, 63.26%, and 62.93%, respectively, under optimal conditions (GLDA and ascorbic acid concentration ratio of 5:20, pH of 3, washing for 60 min, and the liquid-to-solid ratio of 10). GLDA combined with ascorbic acid efficiently removes As, Cd, and Pb from the soil through synergistic proton obstruction, chelation, and reduction. GLDA can chelate with iron and aluminum oxides while directly chelate with Cd and Pb. Ascorbic acid can reduce both Fe(III) to Fe(II) and As(III) to As0. The dissolution of As was promoted by indirectly preempting the binding sites of iron and aluminum in the soil while those of Cd and Pb were improved by directly interrupting the binding sites. This study suggested that GLDA combined with ascorbic acid is an effective cleanup technology to remove As, Cd, and Pb simultaneously from contaminated smelting site soils.

The Discovery of Actinospene, a New Polyene Macrolide with Broad Activity against Plant Fungal Pathogens and Pathogenic Yeasts.

Phytopathogenic fungi infect crops, presenting a worldwide threat to agriculture. Polyene macrolides are one of the most effective antifungal agents applied in human therapy and crop protection. In this study, we found a cryptic polyene biosynthetic gene cluster in Actinokineospora spheciospongiae by genome mining. Then, this gene cluster was activated via varying fermentation conditions, leading to the discovery of new polyene actinospene (1), which was subsequently isolated and its structure determined through spectroscopic techniques including UV, HR-MS, and NMR. The absolute configuration was confirmed by comparing the calculated and experimental electronic circular dichroism (ECD) spectra. Unlike known polyene macrolides, actinospene (1) demonstrated more versatile post-assembling decorations including two epoxide groups and an unusual isobutenyl side chain. In bioassays, actinospene (1) showed a broad spectrum of antifungal activity against several plant fungal pathogens as well as pathogenic yeasts with minimum inhibitory concentrations ranging between 2 and 10 µg/mL.

A dynamic model to evaluate the critical loads of heavy metals in agricultural soil.

Estimation of critical load (CL) is important for soil environmental management and pollution prevention. We developed a mass balance-based dynamic critical load (DCL) model, which improved the model performance, applicability and functionality compared with the traditional one. Paddy soils in two typical fields in central south China and two scenarios were chosen as case studies. The result of case study showed that atmospheric deposition was the main source of Cd, Cu, Pb, and Zn in the soils, with percentage contributions ranging from 59.9 to 79.8%. Crop uptake, particularly the rice straw harvest, was the primary output pathway, accounting for 35.1-71.2% of the total output flux. The critical loads also known as annual input limits (Imax) of heavy metals in the paddy soils were calculated by the developed DCL model. For example, the Imax of Cd was recommended as 0.05 kg ha-1 in the paddy soils under the default scenario for a protection period of 40 years, and that became 0.12 kg ha-1 and 0.17 kg ha-1 under the straw removal scenario in the two typical fields, respectively. The scenario simulation suggested that the straw removal strategy reduced the total concentrations of heavy metals (Ct) in the soils and notably increased the Imax. Meanwhile, the sensitivity analysis indicated that the changes of Ct and Imax can be controlled by adjusting the partition coefficient (Kd), plant uptake factor (PUF) and input flux. The mass balance-based DCL model provides a reference method to establish the standard for controlling heavy metal inputs to agricultural soil, this will be helpful to develop strategies for the prevention of soil contamination.