Microplastic contamination in soil has received increasing attention since excessive plastic debris has been emitted directly into the terrestrial environment. Once released into the terrestrial ...environment, microplastics can be aged via photo- and thermally-initiated oxidative degradation, hetero-aggregation, and bioturbation. Aging affects the physiochemical properties of microplastics with the increase of surface roughness and oxygen-containing groups, which could enhance the sorption and mobility of microplastics in the soil and groundwater environment. However, the interactions among aging, sorption, and transport of microplastics in the terrestrial system have not been unveiled. This review clarifies the key processes of microplastics transport pathways in soil and groundwater ecosystems influenced by aging and sorption under various scenarios. Co-transport of microplastics and sorbed contaminants are also addressed to help understand the risks associated with heavy metals, organic contaminants, and engineered nanoparticles in the soil environment. Overall, this review elaborates the most pressing research limitations on the present literature and highlights the future perspectives to investigate the possible broad transport pathways of microplastics in soil.
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•Aging significantly changes physiochemical properties of microplastics.•The transport of aged microplastics was enhanced in the soil-groundwater environment.•Microplastics can co-transport with soil contaminants by serving as vectors.•Microplastics may transport into groundwater and thus increase the potential risk.
•Dairy manure biochar was more effective than rice husk biochar in removing Pb, Cu, Zn, and Cd.•Dairy manure biochar showed less competitive sorption of metals than rice husk biochar.•Precipitation ...with CO32- or PO43- was mainly responsible for the metal removal by the manure biochar.•Removal of metals by rice husk biochar was mainly due to their complexation with phenonic OH.
Rice husk biochar (RHBC) and dairy manure biochar (DMBC) were prepared as sorbents for simultaneously removing Pb, Cu, Zn, and Cd from aqueous solutions. DMBC was more effective in removing all the four heavy metals than RHBC, with the removal capacities of above 486mmolkg−1 for each metal, much higher than those of RHBC (65.5–140mmolkg−1). RHBC showed stronger competition for metal removal than DMBC when the four metals coexisted, with Pb the least affected and Cd the most inhibited. When each metal was 1mM in the multi-metal system, the metal removal by RHBC was reduced by 38.4–100%, much higher than that reduced by 2–40.9% for DMBC. The stronger competition for metals removal by RHBC was due to the fact that all metals competed only for the ionized phenolic-O− groups, while the removal of metals by DMBC resulted not only from the complexation with ionized hydroxyl-O− groups but also from the precipitation of metals with CO32- and/or PO43- that were rich in DMBC, resulting in less competition. The different mechanisms for the removal of metals by the two biochars were evidenced by the instrumental analysis of XRD, FTIR, and SEM as well as chemical modeling of Visual MINTEQ. Results indicated the waste biomass can be converted into value-added biochar as sorbents for removal of heavy metals and the removal ability varies with different biochar feedstock sources where the mineral components such as CO32-, PO43- originated from the feedstock play an important role in the sorption nature of biochar.
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•Biochars showed higher effectiveness for Hg(II) sorption than activated carbon.•Hg(II) sorption by biochar was mainly attributed to the CC or CO induced Hg-π binding.•Formation of ...(COO)2Hg and (O)2Hg were responsible for the Hg(II) sorption by activated carbon.•Biochar can be a substitute of activated carbon for removal of Hg from wastewater.
Two biochars were produced from bagasse and hickory chips (referred to as BB and HCB, respectively) and evaluated for their sorption ability of Hg(II) in aqueous solution. A commercial activated carbon (AC) which is commonly used for Hg(II) removal was included for comparison. Both biochars showed higher sorption capacities than AC, following the trend of BB>HCB>AC. The sorption of Hg(II) by BB and AC was mainly attributed to the formation of (COO)2HgII and (O)2HgII. As a result, the adsorption capacity of Hg(II) by BB decreased 17.6% and 37.6% after COOH and OH were blocked, respectively and that of Hg(II) by AC decreased 6.63% and 62.2% for COOH and OH hindered, respectively. However, blocking the function groups had little effect on the Hg removal by HCB since sorption of Hg(II) by HCB was mainly resulted from the π electrons of CC and CO induced Hg-π binding. Further X-ray photoelectron spectroscopy analysis indicated the possibility of reduction of the Hg(II) to Hg(I) by phenol groups or π electrons during the removal of Hg(II) by both biochars. In conclusion, biochar is more effective than activated carbon in removing Hg(II) and there exists a high potential that biochar can be a substitute of activated carbon for removal of Hg(II) from wastewater.
Emulsion systems are widely applied in food industry. Several methods have been used for emulsion preparation. Among these methods, high intensity ultrasound (HIU) has attracted much attention ...because it is considered as an eco-friendly and cost-effective method. The acoustic cavitation phenomenon induced by HIU devices can boost the disruption of oil droplets, facilitating the formation of stable emulsions.
This review briefly discusses the major differences between different emulsification devices and the mechanism of ultrasound emulsification process. In addition, emulsion preparation using different emulsifiers such as proteins, polysaccharides and surfactants has been covered in this review. The challenges and future trends of ultrasonic emulsification have also been discussed.
HIU could be used to improve the emulsifying properties of food emulsifiers such as proteins and polysaccharides and enhance the stability of their emulsions. Protein-polysaccharide complex stabilized emulsions produced by HIU showed better stability against environmental stresses than the emulsions stabilized by individual components. Moreover, several studies showed that HIU homogenizers were more energy efficient than high pressure homogenizers and microfluidizers. However, research cooperation between academic institutes and food companies is recommended to develop effective large scale ultrasonic devices.
•The main differences between various emulsification devices are discussed.•The mechanism of ultrasonic emulsification is discussed.•Sonication parameters influenced the physicochemical properties of emulsions.•Emulsion production using ultrasound and various emulsifiers is discussed.•The challenges and future trends of ultrasonic emulsification are discussed.
Biochar is a porous carbonaceous material with high alkalinity and rich minerals, making it possible for CO2 capture. In this study, biochars derived from pig manure, sewage sludge, and wheat straw ...were evaluated for their CO2 sorption behavior. All three biochars showed high sorption abilities for CO2, with the maximum capacities reaching 18.2–34.4 mg g−1 at 25 °C. Elevating sorption temperature and moisture content promoted the transition of CO2 uptake from physical to chemical process. Mineral components such as Mg, Ca, Fe, K, etc. in biochar induced the chemical sorption of CO2 via the mineralogical reactions which occupied 17.7%–50.9% of the total sorption. FeOOH in sewage sludge biochar was transformed by sorbed CO2 into Fe(OH)2CO3, while the sorbed CO2 in pig manure biochar was precipitated as K2Ca(CO3)2 and CaMg(CO3)2, which resulted in a dominant increase of insoluble inorganic carbon in both biochars. For wheat straw biochar, sorbed CO2 induced CaCO3 transformed into soluble Ca(HCO3)2, which led to a dominant increase of soluble inorganic carbons. The results obtained from this study demonstrated that biochar as a unique carbonaceous material could distinctly be a promising sorbent for CO2 capture in which chemical sorption induced by mineralogical reactions played an important role.
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•Biochar is distinctly effective for CO2 capture through both physical and chemical processes.•Elevating temperature and moisture enhance chemisorption of CO2 by biochar.•Rich minerals and high alkalinity of biochar favor CO2 chemisorption.•Mineralogical reactions in biochar promote CO2 transformation into carbonates.
Rich minerals and high alkalinity of biochar favor CO2 chemisorption in which mineralogical reactions promote CO2 transformation into carbonates.
Biochar has been used for immobilizing heavy metals in soils due to its abundant surface functional groups and mineral components. However, as carbonaceous material, biochar in soils is susceptible ...to natural aging, which could alter its structural properties and ability to retain heavy metals. In this study, the impacts of pre- and post-application aging on the properties of dairy manure and sawdust biochars and the significance of different mechanisms of complexation with surface functional groups and mineral precipitation for Cd immobilization in soils were investigated. The simulated natural aging including 25 dry-wet cycles and 25 freeze-thaw cycles decreased the pH of biochar from 8.2 to 10.7 to 7.5–9.7 while increased the release of dissolved organic carbon from 4.1 to 10.9 to 5.9–21.3 mg L−1, O/C ratios from 0.09 to 0.30 to 0.17–0.33, and O-containing functional groups, especially -OH and -C=O groups. New minerals such as CaC2O4 and MgO·MgCO3 were formed during freeze-thaw cycles. The capacity of pre-aged biochars to immobilize Cd in soils decreased from 57-70% to 53–63%, compared to that of fresh biochar, which was mainly due to decrease of CdCO3 or Cd3(PO4)2 precipitation as evidenced by XRD and MINTEQ modeling. By contrast, post-aging of biochar application in soil with dry-wet and freeze-thaw cycling had little effect on the biochar's alkalinity while increased the O/C ratios from 0.10 to 0.24 to 0.15–0.27 and intensity of O-containing functional groups. The immobilization capacity of biochars for Cd in soil increased from 44-68% to 59–73% due to the enhanced surface complexation with O-containing groups. In short, biochar subjected to pre-aging had a reduced capacity to immobilize Cd, while biochars with post-aging in soil increased its Cd immobilization capacity as a soil amendment.
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•Both pre- and post-application aging increased O-containing functional groups of biochar.•Pre-application aging decreased the alkalinity of biochar while the post-application aging had little effect.•Post-application aging increased biochar's capacity to immobilize Cd in soil while pre-application aging decreased it.
Biochar subjected to pre-application aging had a reduced capacity to immobilize Cd, while biochar with post-aging increased its Cd immobilization capacity.
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•The manuscript mainly writes the structure of JAKs and STATs.•The regulation mechanism and negative regulators of JAK/STAT signaling pathway.•Some diseases associated with the ...JAK/STAT pathway and JAKs inhibitors.
The JAK/STAT signaling pathway is an universally expressed intracellular signal transduction pathway and involved in many crucial biological processes, including cell proliferation, differentiation, apoptosis, and immune regulation. It provides a direct mechanism for extracellular factors-regulated gene expression. Current researches on this pathway have been focusing on the inflammatory and neoplastic diseases and related drug.
The mechanism of JAK/STAT signaling is relatively simple. However, the biological consequences of the pathway are complicated due to its crosstalk with other signaling pathways. In addition, there is increasing evidence indicates that the persistent activation of JAK/STAT signaling pathway is closely related to many immune and inflammatory diseases, yet the specific mechanism remains unclear. Therefore, it is necessary to study the detailed mechanisms of JAK/STAT signaling in disease formation to provide critical reference for clinical treatments of the diseases.
In this review, we focus on the structure of JAKs and STATs, the JAK/STAT signaling pathway and its negative regulators, the associated diseases, and the JAK inhibitors for the clinical therapy.
Although accumulating data have suggested the development of cancer in systemic lupus erythematosus (SLE) patients, these results remain inconsistent. To examine such a putative association, this ...analysis reports the association between SLE and the risks of 24 cancer types.
Online databases PubMed, EMBASE, and Web of Science were searched comprehensively for eligible studies, published up to 15 May 2018. Pooled standardized incidence rates (SIRs) with 95% confidence intervals (CIs) were utilized to reveal their associations.
A total of 24 eligible studies were ultimately enrolled. Our results indicated that SLE was associated with increased risk of overall cancers, cancer risk in both genders, non-Hodgkin's lymphoma, Hodgkin's lymphoma, leukemia, multiple myeloma, cervix, vagina/vulva, renal, bladder, esophagus, gastric, hepatobiliary, lung, oropharynx, larynx, non-melanoma skin, and thyroid cancers. Additionally, SLE could reduce the risk of prostate cancer and cutaneous melanoma; however, it was not significantly associated with breast, uterus, ovarian, pancreatic, colorectal, or brain cancers.
Our results shed light SLE being correlated with increased risk for 16 involved cancers and decreased risk for prostate cancer and cutaneous melanoma. This comprehensive meta-analysis provides epidemiological evidence supporting the associations between SLE and cancer risk. This evidence could be utilized to drive public policies and to help guide personalized medicine to better manage SLE and reduce associated cancer morbidity and mortality.
•The antimicrobial activities of four selected flavonoids are evaluated.•Antimicrobial study shows flavonoids cause damage on cell membrane of E. coli.•The lipid model is proposed to study the ...antimicrobial mode of flavonoids.•Location on the cell membrane of E. coli where flavonoids act is obtained.
Antimicrobial mechanism of four flavonoids (kaempferol, hesperitin, (+)-catechin hydrate, biochanin A) against Escherichia coli ATCC 25922 was investigated through cell membranes and a liposome model. The release of bacterial protein and images from transmission electron microscopy demonstrated damage to the E. coli ATCC 25922 membrane. A liposome model with dipalmitoylphosphatidylethanolamine (DPPE) (0.6 molar ratio) and dipalmitoylphosphatidylglycerol (DPPG) (0.4 molar ratio), representative of the phospholipid membrane of E. coli ATCC 25922, was used to specify the mode of action of four selected flavonoids through Raman spectroscopy and differential scanning calorimetry. It is suggested that for flavonoids, to be effective antimicrobials, interaction with the polar head-group of the model membrane followed by penetration into the hydrophobic regions must occur. The antimicrobial efficacies of the flavonoids were consistent with liposome interaction activities, kaempferol>hesperitin>(+)-catechin hydrate>biochanin A. This study provides a liposome model capable of mimicking the cell membrane of E. coli ATCC 25922. The findings are important in understanding the antibacterial mechanism on cell membranes.
•Transport of aged MPs in saturated soils was firstly explored.•Aging enhanced the electrostatic repulsion between MPs and soil particles.•Fe minerals determined the greater retention of MPs in clay ...loam soil.•Modeling was adopted to predict the potential transport risk of MPs in soil-groundwater system.
Microplastics (MPs) inevitably undergo aging transformation and transport process in environmental compartments. In this study, the polystyrene MPs were aged via three different oxidation methods including persulfate oxidation (PS), UV irradiation (UV), and UV irradiated persulfate oxidation (UVPS). All three treatments induced the great transformation of MPs, with the significant increase in surface roughness and in oxygen-containing functional groups, i.e., COOH or COOC. The UVPS aging showed synergetic effect due to the strengthened photo-initiated chemical oxidation, compared to UV and PS alone. All aged MPs exhibited the enhanced transport (34.9%-89.2%) in sandy and clay loam soils than pristine MPs (30.5%), and the synergetic effect was also observed in the transport behaviors of the UVPS MPs. Higher transport of MPs and aged MPs occurred in sandy soil than that in clay loam soil since the latter one contained high Fe minerals that tend to retain MPs, which was confirmed by the model quartz sand column experiment. Modeling on the migration of MPs retained in soil under a rainstorm scenario showed that the aged MPs had the stronger remobility and greater proportion of cumulative flux than pristine ones in the soil profile. These findings provided new insights on the fate and transport of MPs in natural soil and their potential risk to groundwater contamination.
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