Chlorinated volatile organic compounds (Cl-VOCs), including polychloromethanes, polychloroethanes and polychloroethylenes, are widely used as solvents, degreasing agents and a variety of commercial ...products. These compounds belong to a group of ubiquitous contaminants that can be found in contaminated soil, air and any kind of fluvial mediums such as groundwater, rivers and lakes. This review presents a summary of the research concerning the production levels and sources of Cl-VOCs, their potential impacts on human health as well as state-of-the-art remediation technologies. Important sources of Cl-VOCs principally include the emissions from industrial processes, the consumption of Cl-VOC-containing products, the disinfection process, as well as improper storage and disposal methods. Human exposure to Cl-VOCs can occur through different routes, including ingestion, inhalation and dermal contact. The toxicological impacts of these compounds have been carefully assessed, and the results demonstrate the potential associations of cancer incidence with exposure to Cl-VOCs. Most Cl-VOCs thus have been listed as priority pollutants by the Ministry of Environmental Protection (MEP) of China, Environmental Protection Agency of the U.S. (U.S. EPA) and European Commission (EC), and are under close monitor and strict control. Yet, more efforts will be put into the epidemiological studies for the risk of human exposure to Cl-VOCs and the exposure level measurements in contaminated sites in the future. State-of-the-art remediation technologies for Cl-VOCs employ non-destructive methods and destructive methods (e.g. thermal incineration, phytoremediation, biodegradation, advanced oxidation processes (AOPs) and reductive dechlorination), whose advantages, drawbacks and future developments are thoroughly discussed in the later sections.
•Chlorinated volatile organic compounds (Cl-VOCs) are ubiquitous contaminants.•The sources, human health impacts and remediation methods of Cl-VOCs are reviewed.•Future directions on risk and exposure level evaluations of Cl-VOCs are pointed.•State-of-the-art remediation technologies of Cl-VOCs are thoroughly discussed.
The Yinggehai Basin (YB) in the northwest of the South China Sea (SCS) has preserved the complete evolution of the Red River Fault (RRF), whose motion over time has largely contributed to shaping the ...current tectonic framework of the southeastern Tibetan Plateau and Indochina Block. Here we, for the first time, image the RRF, crustal architecture, and crust‐mantle boundary (i.e., Moho) in detail under the YB from two high‐resolution 40‐km‐depth seismic reflection pre‐stack migration profiles. Our seismic reflection images provide direct seismic evidence to support a deep‐penetrating RRF, most likely crosscutting the Moho. In this sense, the RRF was a large‐scale shear zone, along with the clockwise rotation of the Indochina Block, to accommodate the Indochina Block extrusion during Oligocene‐early Miocene and form the YB. We highlight that the material extrusion along deep‐penetrating faults dominated the Tibetan Plateau deformation in response to the India‐Asia collision at an early stage.
Plain Language Summary
The India‐Asia collision has not only created the highest Tibetan Plateau but also resulted in material extrusion outward along multiple large‐scale strike‐slip faults. The Red River Fault (RRF) is suggested to be one of these large‐scale strike‐slip faults. The geometry and deep extension of these strike‐slip faults are fundamental to understanding the manner of the material extrusion. Despite many studies describing geophysical and geological observations of the RRF, its nature in response to the India‐Asia collision remains unknown. The Yinggehai Basin (YB) northwest of the South China Sea with >10 km thick sedimentary has preserved complete evolution of the RRF. In this study, we use high‐resolution deep seismic reflection data with a depth of 40 km, for the first time, to map the crustal architecture, detailed geometries of the crust‐mantle boundary (i.e., Moho) and the RRF under the YB. The seismic reflection images indicate that the RRF is a deep‐penetrating fault that could serve as a large‐scale shear zone. We further highlight that the RRF played a vital role in moving the Indochina Block away from the Tibetan Plateau in response to the India‐Asia collision at an early stage, and subsequently stretching and thinning the continent, eventually forming the YB.
Key Points
For the first time, we image a reflected Moho cut by the Red River Fault (RRF) structure under the Yinggehai Basin (YB), South China Sea
The RRF in the YB is inferred to be a deep‐penetrating fault, most likely cutting through the Moho boundary
The RRF was inferred to be a large‐scale shear zone accommodating the Indochina Block extrusion during Oligocene‐early Miocene
Zeolitic imidazole framework (ZIF) materials, ZIF-9 and ZIF-12 were pioneered to load on cellulose aerogels, and the hybrid aerogels as metal catalysts to effectively activate PMS for p-nitrophenol ...(PNP) degradation. The hybrid aerogels/PMS could remove PNP about 90% in one hour, which hard to remove from water. The experimental results showed that the hybrid aerogels exhibited excellent recyclability, with no significant effect on degradation. The prepared hybrid aerogels are green, environmentally friendly with high catalytic efficiency. Further, the outstanding degradation of PNP demonstrates the promising prospects of hybrid aerogels as advanced oxidation process (AOP) catalysts.
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•A facile method of metal-organic frameworks (MOFs) were loaded onto cellulose aerogels (GEL) to obtain hybrid aerogels.•An efficient hybrid aerogels/peroxymonosulfate (PMS) system was investigated for p-nitrophenol (PNP) removal.•The hybrid aerogels/peroxymonosulfate (PMS) system had a extraordinary pH-tolerant performance.•In the case of maintaining the degradation effect, the hybrid aerogels presented remarkable reusability.
Metal-organic frameworks (MOFs) as catalysts for the activation of peroxymonosulfate (PMS) to remove recalcitrant organic contaminants has been well reported, however, the separation of MOFs from the solution is difficult because of their powder state, which limits their applications. In the present study, zeolitic imidazole framework (ZIF) materials, ZIF-9 and ZIF-12 were pioneered to load on cellulose aerogels, and the hybrid aerogels as metal catalysts to effectively activate PMS for Rhodamine B (RB), tetracycline hydrochloride (TC) and p-nitrophenol (PNP) degradation. The hybrid aerogels/PMS system could remove PNP about 90% in 1 h, which hard to remove from water. The pH value of the solution had no effect on the degradation process, which demonstrated that the hybrid aerogels had excellent pH tolerance. In addition, the mechanism of PNP degradation was investigated by electron paramagnetic resonance (EPR) and free radical trapping methods. The results showed that PMS could effectively activate by hybrid aerogels to produce sulfate radicals (SO4−), hydroxyl radicals (OH), and revealed that SO4− play a key role in degradation. The most important feature of hybrid aerogels is can be easily separated from the solution. The obtained results showed that the hybrid aerogels exhibit excellent recyclability, with no significant effect on degradation. The prepared hybrid aerogels are green, environmentally friendly with high catalytic efficiency. Further, the outstanding degradation of PNP demonstrates the promising prospects of hybrid aerogels as advanced oxidation process (AOP) catalysts.
High-fat diet (HFD) decreases insulin sensitivity. How high-fat diet causes insulin resistance is largely unknown. Here, we show that lean mice become insulin resistant after being administered ...exosomes isolated from the feces of obese mice fed a HFD or from patients with type II diabetes. HFD altered the lipid composition of exosomes from predominantly phosphatidylethanolamine (PE) in exosomes from lean animals (L-Exo) to phosphatidylcholine (PC) in exosomes from obese animals (H-Exo). Mechanistically, we show that intestinal H-Exo is taken up by macrophages and hepatocytes, leading to inhibition of the insulin signaling pathway. Moreover, exosome-derived PC binds to and activates AhR, leading to inhibition of the expression of genes essential for activation of the insulin signaling pathway, including IRS-2, and its downstream genes PI3K and Akt. Together, our results reveal HFD-induced exosomes as potential contributors to the development of insulin resistance. Intestinal exosomes thus have potential as broad therapeutic targets.
Rice is a major source of cadmium (Cd) intake for Asian people. Indica rice usually accumulates more Cd in shoots and grains than Japonica rice. However, underlying genetic bases for differential Cd ...accumulation between Indica and Japonica rice are still unknown. In this study, we cloned a quantitative trait locus (QTL) grain Cd concentration on chromosome 7 (GCC7) responsible for differential grain Cd accumulation between two rice varieties by performing QTL analysis and map‐based cloning. We found that the two GCC7 alleles, GCC7PA64s and GCC793‐11, had different promoter activity of OsHMA3, leading to different OsHMA3 expression and different shoot and grain Cd concentrations. By analyzing the distribution of different haplotypes of GCC7 among diverse rice accessions, we discovered that the high and low Cd accumulation alleles, namely GCC793‐11 and GCC7PA64s, were preferentially distributed in Indica and Japonica rice, respectively. We further showed that the GCC7PA64s allele can be used to replace the GCC793‐11 allele in the super cultivar 93‐11 to reduce grain Cd concentration without adverse effect on agronomic traits. Our results thus reveal that the QTL GCC7 with sequence variation in the OsHMA3 promoter is an important determinant controlling differential grain Cd accumulation between Indica and Japonica rice.
Indica rice usually accumulates more Cd in shoots and grains than Japonica rice. However, the underlying mechanisms are unknown. Here, we show that natural variation in the OsHMA3 promoter influences OsHMA3 expression and Cd accumulation subsequently, implying that it is an important factor determining differential Cd accumulation between Indica and Japonica rice cultivars.
Magnetized topological insulator multilayers Lei, Chao; Chen, Shu; MacDonald, Allan H.
Proceedings of the National Academy of Sciences - PNAS,
11/2020, Volume:
117, Issue:
44
Journal Article
Peer reviewed
Open access
We discuss the magnetic and topological properties of bulk crystals and quasi–two-dimensional (quasi-2D) thin films formed by stacking intrinsic magnetized topological insulator (for example, Mn ...(SbₓBi1–x
)₂X₄ with X = Se,Te) septuple layers and topological insulator quintuple layers in arbitrary order. Our analysis makes use of a simplified model that retains only Dirac cone degrees of freedom on both surfaces of each septuple or quintuple layer. We demonstrate the model’s applicability and estimate its parameters by comparing with ab initio density-functional theory (DFT) calculations. We then employ the coupled Dirac cone model to provide an explanation for the dependence of thin-film properties, particularly the presence or absence of the quantum anomalous Hall effect, on film thickness, magnetic configuration, and stacking arrangement, and to comment on the design of Weyl superlattices.
From the apex of the NW Sub-basin of the South China Sea, we present new long-cable deep-penetration seismic profiles and deepwater drillings together with corrected seismic interpretations from ...previous studies. Structural mapping demonstrates that the Xisha Trough is characterized by a hyper-extended rift system that shows evidence of extremely thinned crust and rotated fault blocks. A series of NE, NEE and W-E striking listric normal faults along the Xisha Trough, which merge at depth into Moho reflection, record strongly extensional deformation. Based on the absence of an acoustic basement beneath a wedge-shaped rifted sequence, we document three diapiric magma structures exiting the Moho and penetrating into the extremely thinned continental crust, which is covered by a Cenozoic sequence. For the Xisha Trough we can demonstrate, based on seismic data and calculated fault slip rates, the faults bounding the Xisha Trough were initially formed by distributed rifting, and were reactivated and focused on faulting along the axis of the Xisha Trough. However, the peak faulting migrated along the margin strike from east to west and terminated at the apex of the Xisha Trough. One of the key processes, controlling the evolution of the Xisha Trough, is depth-dependent extension, which may arise from differential lithospheric stretching by regional dynamic lower crustal/mantle flow.
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•Along strike variations in the hyper-extended crustal and basin structures ahead of the V-shaped oceanic propagator.•Deformation evolved from diffuse and wide to more localized deformation.•Extreme crustal thinning and dynamic lower crustal/mantle flow occurred there.
The system observability enabled by distribution-level PMUs becomes increasingly crucial for cyber-physical security enhancement. We formulate this system observability as a disjunctive relaxed ...connected dominating set problem for reconfigurable distribution networks with the least defense cost in theory. For the benefits of system observability, an observability defense-constrained distribution network reconfiguration (DNR) model has been proposed. This DNR model is then converted to a mixed integer second-order conic programming problem, which thus can be solved with commercial solvers in case studies.
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