There are global concerns about heavy metal (HM) contamination in soils, which in turn has produced an increased demand for soil remediation. Biochar has been widely documented to effectively ...immobilize metals in contaminated soils and has received increasing attention for use in soil remediation. Here, we review recent progresses in understanding metal-biochar interactions in soils, potential risks associated with biochar amendment, and application of biochar in soil remediation in China. These recent studies indicate that: (1) the remediation effect depends on the characteristics of both biochar and soil and their interactions; (2) biochar applications could decrease the mobility/bioavailability of HMs in soils and HM accumulation in plants; and (3) despite its advantages, biochar applications could pose ecological and health risks, e.g., by releasing toxic substances into soils or by inhalation of biochar dust. Research gaps still exist in the development of practical methods for preparing and applying different biochars that target specific HMs. In the future, the long term effects and security of biochar applications on soil remediation, soil organisms and plant growth need to be considered.
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•The metal-biochar interactions and mechanisms in soils were reviewed.•Potential risks associated with biochar amendment were discussed.•Cases of biochar application in soils in China were summarized.•Long term effects of biochar on soil remediation need further investigation.
The remediation of heavy metal contaminated soils by biochar in China was reviewed, including metal-biochar interactions and mechanisms, its application risk and status.
The present study was conducted to estimate the effects of dietary carbohydrates on muscle quality and the underlying mechanisms. Six isonitrogenous and isolipidic diets were formulated to contain ...graded levels of carbohydrates (0%, 8%, 12%, 16%, 20% and 24%, respectively). These diets were named as C0, C8, C12, C16, C20 and C24, respectively. After a 10-week feeding trial, results showed that the muscle pH, liquid holding capacity (LHC) and hardness were significantly decreased by the increasing dietary carbohydrate levels. Dietary carbohydrates significantly decreased the muscle fibre diameter, and the highest value was found in the C0 group. Accumulated glycogen and degenerated mitochondrial cristae were observed in the C24 group. Significantly higher contents of protein carbonyls were observed in the C20 group and C24 group (P < 0.05). There was a significant decrease of mtDNA copy number in the C24 group compared with that in the C0 and C8 groups. The AMP/ATP ratio in muscle decreased first and then increased with the increasing dietary carbohydrate levels. The dietary incorporation of carbohydrate significantly reduced the expression of opa1, pygm and genes involved in myogenesis (myf5 and myog). Meanwhile, proteolysis-related genes (murf-1, mafbx, capn2 and ctsl), pro-inflammatory cytokines (il-6 and tnf-α) and mstn were significantly up-regulated. In the C24 group, significant increase of phosphorylation of AMPK (Thr172), up-regulation of PGC-1α and GLUT4 were observed, while the phosphorylation level of S6 (Ser235/236) was significantly decreased. It was concluded that excessive dietary carbohydrate level (24%) had negative impacts on mitochondria function and promoted glycogen accumulation, and thereafter influenced the muscle quality of olive flounder. The activation of AMPK as well as the upregulation of PGC-1α and GLUT4 was the key mechanism.
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•Sorption mechanism of sulfamethazine (SMT) to different biochars was observed.•The presence of methacrylic and citric acids generally enhanced SMT adsorption.•Humic acid restrained ...the sorption of SMT to biochar produced at 600°C.•Bovine serum albumin showed a complicated effect on the sorption of SMT species.•Sorption of SMT was insignificantly affected by malic acid and sodium alginate.
Sorption characteristic of sulfamethazine (SMT) to straw biochars pyrolyzed at 300°C (BC300) and 600°C (BC600), and the effect of ubiquitous DOM were investigated. Results showed that physisorption (partition) and weak chemical binding (π-π EDA interaction) dominated the sorption of SMT to BC300 and BC600, respectively. Graphene sheets in biochar played important roles in the sorption of SMT, leading to higher sorption capacity (Kf) on BC600 (1.77mg1−nLng−1) than BC300 (0.11mg1−nLng−1). Sorption amount of SMT to BC300 was not affected by polysaccharide and malic acid, while it was slightly promoted by citric acid, but dramatically increased 1.25 times by methacrylic acid through decreasing solution pH and providing new sorption sites. Humic acid and bovine serum albumin restrained the sorption of SMT to BC600, but enhanced SMT− adsorption to BC300. The chemical nature of DOM, biochar properties and antibiotic species co-determined the impact of DOM on antibiotics adsorption.
Carnivorous fish is thought to be high-glucose intolerance. But the reasons were still unclear. The aim of the present study is to investigate the effects of high level of dietary carbohydrate on the ...survival, growth and immune responses of Paralichthys olivaceus, and the underlying molecular mechanism related to the immune and glucose metabolism. P. olivaceus were fed with 8%, 16% and 24% of dietary carbohydrate for 10 weeks, respectively. After that, a glucose tolerance test (GTT) was conducted. Results showed that excessive (24%) dietary carbohydrate significantly decreased the growth and glucose tolerance ability according to the GTT. It significantly increased hepatic NADPH oxidase activity and malondialdehyde content and serum contents of IL-6 and advanced glycation end products. The expressions of glucose transport-relevant genes in liver and the content of related hormones in serum were analyzed. In conclusion, it was confirmed that IL-6 increased the expression of suppressor of cytokine signaling 3 (SOCS3) and regulated the downstream targets of PI3K-AKT mediated signal transduction, and then downregulated the glucose transporter 2 activity in liver of P. olivaceus fed diet with excessive carbohydrate level. It was suggested that SOCS3 served as a bridge between immune response and glucose metabolism in P. olivaceus.
Microplastics (MPs) as a ubiquitous environmental pollutant have drawn growing attention, and it is concerning that children are more sensitive to MPs than adults. Unfortunately, information about ...the link between children and MPs is insufficient. Therefore, we review the sources and exposure routes of children to MPs and collect evidence for the potential risks. Children can ingest and/or inhale MPs derived from various foodstuffs and plastic products. Despite the limited knowledge on the toxicity to humans, current studies have proved the accumulation and translocation of MPs in different tissues and organs. Main damages including cytotoxicity, neurotoxicity, and immunotoxicity can be caused by pristine polymers and/or co-contaminants. There is much more to be understood about MPs, especially their health effects, and this study has made it clear that it is time to protect our future generations from the threat of MPs.
Graphic Abstract
Microplastics (MPs) can pose ecological risk to the environment and have the potential to negatively affect human health, raising serious public concerns. It is recognized that MPs could act as a ...vector for various environmental pollutants including heavy metals and potentially influencing their mobility, fate, and bioavailabilty in the environment. However, knowledge on the mechanisms underpinning the interaction processes between MPs and heavy metals is far from clear. This review discusses the effects of MPs on the adsorption/desorption, speciation and bioavailability, and toxicity of various heavy metals. The present review also systematically identifies the environmental factors (e.g., pH, ionic strength, and organic matters) that could affect their interaction processes. This work aims to establish a meaningful perspective for a comprehensive understanding of the indirect ecological risks of MPs as vectors for contaminants. The work also provides a reference for the development of better regulatory strategies in mitigating the negative effects caused by the co-existence of MPs and heavy metals.
Smectite clays are widely found in subsurface soils and waters. Although they strongly sequester tetracyclines (TCs), little is known about their reactions with these antibiotics under dark anoxic ...conditions. This study investigated the interactions between TCs and Fe-bearing smectite clays and the influences of environmental factors. Fe-bearing smectite clays were shown to significantly induce the transformation of TCs, including tautomerization, dechlorination, and dehydration. Moreover, the adsorbed TCs reduced the structural Fe(III) in clay particles to structural Fe(II) through electron transfer. The transformation of TCs was more readily induced by smectite clays with a higher rather than a lower Fe content. Tetrahedral Fe(III), and distorted cis- or trans-octahedral Fe(III), were more reactive as an electron acceptor than cis-octahedral Fe(III), as observed on the Mössbauer and FTIR spectra. A lower pH facilitated the adsorption of TCs through dimethyl-amino, amide, and conjugated –OH functional groups and induced a higher rate of TCs transformation. The transformation of chlortetracycline (CTC) was faster than that of oxytetracycline or tetracycline (TTC) due to -Cl substitution. The major transformation CTC products included keto-CTC, epi-CTC, iso-CTC, anhydro-CTC and TTC. Mixtures of these transformed products were found to have a higher acute toxicity than their parent compounds to Photobacterium phosphoreum T3. Our study revealed several previously overlooked interactions between TCs and clay particles that could cause these antibiotics to become unstable in the subsurface environment, with negative effects on the soil-borne microbial community.
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•Tautomerization, dehydration and dechlorination of TC can occur on clay surfaces.•Structural Fe(III) in clays can be reduced to structural Fe(II) by adsorbed TCs.•Octahedral Fe with distorted cis- or trans-conformation are more active than cis-conformation.•Transformation products of TCs with clays have higher acute toxicity than their parent compounds.
In recent years, ultrawide bandgap semiconductor materials represented by aluminum nitride (AlN) have attracted worldwide attention due to their excellent high-frequency power characteristics, stable ...high-temperature performance, low energy loss, and good ultraviolet (UV) transmittance. They have great application prospects in the fields of high-efficiency optoelectronic devices, high-power and high-frequency electronic devices, ultra-high voltage power electronic devices, deep UV warning and guidance, and deep UV-LED disinfection. The physical vapor transport (PVT) method has the advantages of a simple growth process, fast growth rate, and high crystal integrity, and has gradually become one of the most effective methods for growing bulk AlN crystals. This review systematically summarizes the latest research progress in AlN crystals grown by the PVT method in recent years, and introduces their applications in deep UV-LEDs, UV lasers and Schottky barrier diodes (SBDs). Finally, the challenges and application prospects of AlN crystals are discussed. As an important new type of direct bandgap ultrawide bandgap semiconductor material, AlN crystals have shown extremely important strategic application value. The output power of deep UV-LED devices meets practical requirements, and high-power electronic power devices are still in the verification stage. From the perspective of material superiority, they have considerable development potential.
This review systematically summarizes the latest research advances of AlN crystals grown by the PVT method and their applications.
Some of community mitigation efforts on COVID-19 created challenges to ongoing public health programs, including HIV care and prevention services among men who have sex with men (MSM). The goal of ...the current study was to explore sociodemographic factors and the impact of COVID-19 on HIV testing among Chinese MSM during state-enforced quarantine.
We conducted a community based survey between May 1st to June 30th, 2020 on COVID-19 related impacts on HIV testing among 436 China MSM during the COVID-19 state-enforced quarantine.
One-third (33.7%) of MSM received HIV testing during the quarantine period. Few participants reported difficulty accessing facility-based testing (n = 13, 3.0%) or obtaining HIV self-test kit online (n = 22, 5.0%). However, 12.1% of participants reported being afraid of getting facility-based HIV test due to concerns about the risk of COVID-19. In the multivariate logistic regression model, participants who were married (aOR: 1.89, 95%CI: 1.19-3.01), reported increased quality of sleep (aOR: 2.07, 95%CI: 1.11-3.86), and increased difficulty in accessing health care (aOR: 2.34, 95%CI: 1.37-3.99) were more likely to get an HIV test during the state-enforced quarantine.
The mitigation measures of COVID-19 have created various barriers to access HIV related prevention services in China, including HIV testing. To mitigate these impacts on HIV prevention and care services, future programs need to address barriers to HIV-related services, such as providing high-quality HIV self-testing. Meanwhile, psychological services or other social services are needed to those experiencing mental distress.
A series of trace Fe
3+
-doped KH
2
PO
4
single crystals were grown using the conventional temperature cooling method. The Fe
3+
ion content in the as-grown crystals and the corresponding ...transmission spectrum were measured, respectively. With an increase of Fe
3+
ion concentration, the transmittance of the crystal gradually decreases within the wavelength range of 200 nm to 370 nm. Under picosecond pulse laser irradiation, third-order nonlinear optical characteristics were systematically measured at
λ
= 532 nm. The existence of nonlinear absorption and nonlinear refraction was demonstrated. The results show that the nonlinear refractive index
n
2
is positive, indicating the presence of a self-focusing effect for the as-grown crystals. Specially, nonlinear absorption and refraction have a heavy dependence on the Fe
3+
ion content and crystal directions (
II
and
z
). With increasing Fe
3+
ion concentration, a significant variation has been observed with respect to the nonlinear absorption coefficient
β
, nonlinear refractive index
n
2
and third-order nonlinear susceptibility
χ
(3)
. A similar pattern for
II
<
z
has been presented for nonlinear absorption and refraction. The investigations suggest that nonlinear absorption and refraction caused by distortion of the electron cloud might be associated with the H
2
PO
4
−
and (FeO
4
)
2−
groups.
A series of trace Fe
3+
-doped KH
2
PO
4
single crystals were grown using the conventional temperature cooling method.
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