RESUMEN
The advantages of microbial induced carbonate precipitation (MICP) as bio-cementation technology for tailings-solidification are under extensive investigation. In order to improve performance of bio-cementation, many strengthening materials were applied to the bio-cementation of tailings. Steel slag (SS) is a kind of industrial solid waste, its chemical composition and mineral composition are similar to cement, and it has a certain application prospect as an auxiliary cementing material. In this study, the properties and mechanism of SS strengthening MICP cementation of cyanide tailings (CT) were investigated. The results showed that Sporosarcina pasteurii growth is not inhibited by SS, and Sporosarcina pasteurii can promote the hydration reaction of SS, providing a suitable alkaline environment and Ca2+, promoting the production of more CaCO3 in the MICP process. When 200 mL of CT leachate was added 1.4 g SS (200-400 mesh), the adsorption of Cu, Pb, Zn, Cd, total cyanide (T-CN), and free cyanide (F-CN) reached 48.05%, 44.28%, 36.25%, 16.67%, 79.05%, and 67.20%, respectively. The maximum unconfined compressive strengthï¼UCSï¼ of the cemented body (with 5%, 150 mesh SS) was 1.97 MPa, which was 3.396 times as high as that without SS. The cemented body with the addition of SS (5%, 150 mesh) contained more carbonate bound Cu (2.75%), Pb (4.89%), Zn (5.37%), and Cd (5.75%), and less exchangeable Cu (3.65%), Pb (6.85%), Zn (2.27%), and Cd (4.42%) than that without SS. In summary, the addition of SS improved the UCS of cemented bodies and the stability of heavy metals and cyanide, reduced the environmental risks existing in the process of CT storage. Meanwhile, it also provides new ideas for resource utilization of industrial solid waste SS and improvement of mine filling materials.
Asunto(s)
Metales Pesados , Residuos Sólidos , Acero , Cementación , Cianuros , Cadmio , Plomo , Metales Pesados/química , Carbonatos/química , Carbonato de CalcioRESUMEN
Fresh biochar has been widely applied to the remediation of heavy metals in soil by its property of adsorption, but the changes in its physicochemical properties and in situ adsorption performance over time cannot be ignored. In this study, the sorption of Cd2+ by corn straw biochars (CB) and municipal sludge biochars (SB) produced at 350 °C and 650 °C before and after H2O2 oxidation, and dry-wet and freeze-thaw aging were investigated using batch sorption experiments. The changes of physicochemical properties of biochar before and after aging were analyzed by various characterization methods. Based on these results, the impact of aging on the Cd2+ adsorption behavior could be clarified, which showed that CB650 was able to display the highest adsorption capacity in fresh biochars. Aging treatments reduced the ash content and pH value of CB, and significantly diminished the adsorption performance of Cd2+. These changes indicated that precipitation was a critical factor in the adsorption of Cd2+ on CB. The adsorption capacity of SB was enhanced after H2O2 oxidation, but weakened after dry-wet and freeze-thaw aging. This was closely related to the increase or decrease in the content of oxygen-containing functional groups, which in turn enhanced or inhibited its ability to compound with heavy metals. These results are of great significance for evaluating its long-term application prospects in the natural environment.
Asunto(s)
Metales Pesados , Contaminantes del Suelo , Cadmio/análisis , Adsorción , Peróxido de Hidrógeno , Contaminantes del Suelo/análisis , Carbón Orgánico/química , Suelo/química , Zea maysRESUMEN
Although biochar has been widely used in the remediation of heavy metal pollution in acidic and neutral soils, less attention has been paid to whether biochar will alter its structural properties and the ability to retain heavy metals after different degrees of aging in alkaline soils. In this study, two artificial accelerated aging methods (freeze-thaw cycle and dry-wet cycle) and a short-term natural aging method were used to simulate the aging process of biochar prepared from corn stalk. We investigated the changes in the soil pH and bioavailability, total content, and transformation of Cd2+ before and after aging treatments. Biochar was separated from the soil for characterization to explore the effect of aging on the passivation of Cd2+ by biochar in the alkaline soil of the mining area. The results showed that adding biochar to alkaline soil in the Bayan Obo mining area had no significant liming effect, and pH decreased after the freeze-thaw and dry-wet accelerated aging treatments. Compared with that in the control, the CaCl2-extractable contents of Cd2+ decreased by 19.32%-30.67%, and the total contents of Cd2+ decreased by 5.02%-7.18%. Aging did not significantly change the transformation of Cd2+ but reduced the distribution of acid-soluble and reducible fractions, indicating that biochar could immobilize Cd2+ for a long time after aging, which was related to the increase in oxygen-containing functional groups and the pore structure of biochar. These results are important for evaluating its long-term application prospects in the mining environment.
Asunto(s)
Metales Pesados , Contaminantes del Suelo , Suelo/química , Cadmio/análisis , Contaminantes del Suelo/análisis , Carbón Orgánico/química , Metales Pesados/análisisRESUMEN
BACKGROUND: Gray mold caused by Botrytis cinerea is an airborne plant pathogen with a necrotrophic lifestyle that infects more than 200 crops worldwide. Florylpicoxamid is a second-generation picolinamide fungicide inspired by a natural product. Florylpicoxamid targets the Qi site of the mitochondrial cytochrome bc1 complex and is currently being registered in China for the control of gray mold in a variety of crops. Although a broad spectrum of activity and attributes have been reported for florylpicoxamid, little is known about its effectiveness against gray mold or its protective and curative properties. RESULTS: Florylpicoxamid exhibited substantial inhibitory activity against 12 tested species of plant-pathogenic fungi, with effective concentration for 50% growth inhibition (EC50 ) values ranging from 0.017 to 2.096 µg ml-1 . A total of 129 isolates of B. cinerea from ten regions were tested for their sensitivity to florylpicoxamid, and the mean EC50 value was 0.04 ± 0.017 µg ml-1 . Furthermore, florylpicoxamid was observed to substantially inhibit all developmental stages of B. cinerea, with mycelial development, sclerotium germination, germ tube elongation and conidial germination being restrained with an EC50 value of 0.051 ± 0.0072, 0.012 ± 0.0069, 0.019 ± 0.0041 and 0.0062 ± 0.0007 µg ml-1 , respectively. No cross-resistance was observed between florylpicoxamid and quinone outside inhibitor (QoI), methyl benzimidazole carbamates or succinate dehydrogenase inhibitor. Florylpicoxamid also exhibited protective and curative activity against the development of B. cinerea infection in tests on tomato fruits. At application rates of 90, 112.5 and 135 g a.i. ha-1 , florylpicoxamid was also observed to provide more-effective control than boscalid (300 g a.i. ha-1 ). CONCLUSION: This study demonstrated that the novel fungicide florylpicoxamid exhibits strong inhibitory activity against B. cinerea, regardless of the resistance profiles of those isolates to tested fungicides with different modes of action. This makes florylpicoxamid a powerful new solution to optimize gray mold control and manage fungicide resistance. © 2022 Society of Chemical Industry.
Asunto(s)
Farmacorresistencia Fúngica , Fungicidas Industriales , Enfermedades de las Plantas/microbiología , Botrytis , Fungicidas Industriales/farmacologíaRESUMEN
G9a is a lysine methyltransferase that regulates epigenetic modifications, transcription, and genome organization. However, whether these properties are dependent on one another or represent distinct functions of G9a remains unclear. In this study, we observe widespread DNA methylation loss in G9a depleted and catalytic mutant embryonic stem cells. Furthermore, we define how G9a regulates chromatin accessibility, epigenetic modifications, and transcriptional silencing in both catalytic-dependent and -independent manners. Reactivated retrotransposons provide alternative promoters and splice sites leading to the upregulation of neighboring genes and the production of chimeric transcripts. Moreover, while topologically associated domains and compartment A/B definitions are largely unaffected, the loss of G9a leads to altered chromatin states, aberrant CTCF and cohesin binding, and differential chromatin looping, especially at retrotransposons. Taken together, our findings reveal how G9a regulates the epigenome, transcriptome, and higher-order chromatin structures in distinct mechanisms.
Asunto(s)
Cromatina/metabolismo , Metilación de ADN , Antígenos de Histocompatibilidad/metabolismo , N-Metiltransferasa de Histona-Lisina/metabolismo , Cromatina/genética , Antígenos de Histocompatibilidad/genética , N-Metiltransferasa de Histona-Lisina/genética , Histonas/genética , Histonas/metabolismo , Humanos , RetroelementosRESUMEN
According to sexual selection theory, age affects the preference of mate choice, and this preference ultimately influences the fecundity of the female. Pardosa pseudoannulata (Araneae: Lycosidae) is a valued predator in many cropping systems. By determining oviposition rate, egg hatching rate, and also the number and carapace width of the 2nd instar spiderlings of the F1 generation, we explored the effects of age on fecundity of the female spider. There were no significant effects of age on courtship duration, sexual cannibalism rate, mating rate, oviposition rate, egg hatching rate, or the number and carapace width of 2nd instar spiderings of P. pseudoannulata. However, age had a significant effect on courtship latency, courtship intensity, and mating duration of the spider. Courtship latency decreased significantly with an increase in the age of the male, and courtship intensity of the low-age male increased with increasing female age. Increasing age of male and female spiders was associated with significantly prolonged mating duration. The results indicated that low-age male spiders were more inclined to mate with high-age females, and age had no significant effect on sexual cannibalism rate or the fecundity of the female.
Asunto(s)
Copulación/fisiología , Cortejo/psicología , Fertilidad/fisiología , Arañas/fisiología , Factores de Edad , Animales , Canibalismo , Femenino , Masculino , Oviposición/fisiologíaRESUMEN
Oxide-covered aluminium electrodes were used to demonstrate that aromatic compounds, such as the simple derivatives of benzene, can be electrochemically excited at cathodically pulse-polarized conductor/insulator/electrolyte (C/I/E) tunnel junction electrodes (e.g. oxide-covered aluminium electrodes). The primary cathodic process at these electrodes was a tunnel emission of hot electrons into an aqueous electrolyte solution. Fluorescence (FL) and electrochemiluminescence (ECL) spectra were compared and the dependence of the electrochemiluminescence on the concentrations of benzene, toluene, phenol, p-cresol and aniline were measured and detailed mechanisms for the present electrochemiluminescence are proposed.