As a new type of pollutant, microplastics have attracted increased attention because of their widespread and persistent existence in the water environment. In this study, we investigated one of the ...eight largest lakes in China—Wuliangsuhai Lake in Inner Mongolia. The microplastic concentration in Wuliangsuhai Lake ranges from 3.12 to 11.25 n/L. The different functional areas in Wuliangsuhai can be divided into four categories, namely effluent, fishing, intake and wetland areas. The highest microplastic concentration occurs in the intake area. The collected microplastics are divided into four types, i.e., fibers, pellets, fragments and films, of which fibers are the most abundant. Among the four functional areas of Wuliangsuhai Lake, the highest fiber concentration is observed in the fishing area. The microplastics in Wuliangsuhai Lake are mainly small size, and the microplastics smaller than 2 mm account for 98.2% of the total microplastics, while the microplastic size in the intake area is relatively large. Polystyrene and polyethylene are the main polymer types. Agricultural wastewater, domestic sewage and fishery discharge have the greatest impact on the microplastic distribution. This study reveals that the inland lakes in northern China are polluted by microplastics, which may cause potential harm to the surrounding environment.
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•Microplastics occurrence in Wuliangsuhai Lake were investigated.•The dominant microplastics were polystyrene fiber with 0–2 mm in size.•The discharge of human sewage and industrial wastewater were the main source of microplastics.•The spatial distribution of microplastics varies between different functional areas.
Microplastics, as an emerging class of pollutants has become a global concern, and is receiving increasing attention. Interestingly, microplastics are always in their ageing process when they enter ...the real environment. Our study investigated the ageing properties of polystyrene (PS) plastics in air, pure water and seawater environments at 75 °C. A two-dimensional (2D) Fourier transform infrared (FTIR) correlation spectroscopy (COS) analysis was used to better understand the ageing mechanism of the PS plastics. Based on the 2D-COS analysis, different ageing mechanisms were identified under different ageing conditions, such as an ageing sequence of aged-PS particle functional groups in air: 1601(CC) > 1050(C–O)>1453(C–H)>1493(C–H)>1375(C–OH)>1666(CO). Among the functional group changes, O-functional groups (C–O, C–OH and CO) were introduced during the ageing process. Moreover, for pristine PS particles, hydrophobicity was a major factor for the interaction between the microplastics and organic pollutants. For aged-PS particles, their adsorption capacities were significantly enhanced as the degree of ageing increased. The ageing degree of PS was highly responsible for increasing of the specific surface area and the increase in oxygen-containing surface groups. Furthermore, there was a significant enhancement in the adsorption affinity for antibiotic contaminants than for polycyclic aromatic hydrocarbon contaminants. Aged PS particles had little adsorption of polycyclic aromatic hydrocarbons, because the presence of oxygen-containing surface groups on the aged PS plastics might allow the formation of hydrogen bonds with the surrounding water molecules. Overall, a 2D-COS analysis was an effective method for understanding the ageing process of microplastics under different environmental conditions at high temperature. These results also clearly demonstrated the characteristics and mechanisms of the interaction between aged-microplastics and organic pollutants, which could be useful for understanding the environmental behavior of co-existing pollutants.
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•Microplastics were aged by air, pure water and seawater on 75 °C.•The aging mechanism of PS were different under different aging conditions.•The adsorption capacities of PS were enhanced with the increase of aging degree.•The adsorption of PS on organic pollutants depend on its properties.
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•PS were aged by air, pure water and seawater under UV irradiation.•Changes in chemical/physical properties of PS were examined by FTIR, XPS, XRD and SEM.•Aging mechanisms of PS in ...water environment is different from that in air.•Aging can significantly improve the adsorption of heavy metals by PS.
Microplastics are formed by the degradation of plastic wastes under the action of physicochemical mechanisms in environment, and they are becoming a new type of pollutant that is attractings global attention. However, research on the aging characteristics and mechanism of microplastics is limited. The aging mechanism of Polystyrene (PS) with UV irradiation under different conditions (air, pure water and seawater) and the effect of aging on heavy metal adsorption were studied. The results show that PS have different characteristics with UV irradiation under different conditions, and the aging of PS is the most obvious in air. Based on the 2D-COS analysis, different aging mechanisms were identified under different aging conditions, aging sequence of aged PS functional groups in air and water were clearly definited. An isothermal adsorption model shows that aging can significantly increase the adsorption of heavy metals by PS. The adsorption of heavy metals is also affected by different aging methods. Over all, a 2D-COS analysis was an effective method for understanding the aging process of PS. These results further clarify the aging mechanism of PS, and provides a theoretical basis for the assessment of environmental behavior and ecological risk when microplastics and heavy metals coexist.
Microplastics are ubiquitous in the environment, sediments in the water body are considered as the sink of microplastics, but its accumulation and change trend have received little attention. We ...assessed the concentrations of microplastics in sediment samples collected in Wuliangsuhai Lake. The abundance of microplastics (0–6 cm) in surface sediment ranged from 16.5 to 72.4 particles 100 g−1 dry weight. The results show that the abundance, type and size of microplastics in surface sediment of different functional areas are different. Four sampling points were selected to investigate the vertical distribution of microplastics. The abundance of microplastics exhibited a clear decreasing trend with increased sediment depth, the abundance of microplastics in deep sediments is much less. This result shows that when estimating the storage of microplastics in sediments, if only considered the surface sediments, the assessment of microplastic storage worldwide might be underestimated.
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•Microplastics in sediments of Wuliangsuhai Lake were investigated.•Fiber-shaped, small size microplastics (<1 mm) were the most common type.•Anthropogenic activities affect microplastics distribution in Wuliangsuhai Lake sediment.•Microplastic abundance decreased with depth and increased with age in the sediment.
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•A multi-yolk-shell structure is constructed to disclose the reaction activity of Fe-based compounds toward potassium-ion storage.•FeSe2@C shows superior rate capability due to the ...good electron/K+ conductivity of FeSe2 and its excellent pseudocapacitive behavior.•The weak electron conductivity of FeS2 and large K+ diffusion barrier of FeP result in inferior potassium storage performance.
Iron-based compounds have been extensively applied as anode materials for alkali-ion batteries. Nevertheless, how the intrinsic properties of Fe-based compounds affect their alkali-ion storage behavior still remain blurry, hampering the rational structure design of Fe-based anodes for superior performance. Herein, the reaction activities of various Fe-based compounds (e.g., FeS2, FeSe2, and FeP) toward K/Na/Li-ion storage are studied by rationally encapsulating Fe-compounds into hollow carbon boxes with an identical multi-yolk-shell structure. For potassium storage, FeSe2@C composite manifests the best battery performance with high capacity, superior rate capability, and excellent cycling behavior. FeS2@C exhibits high capacity, but with poor cycling retention and inferior rate capability. FeP@C shows the lowest capacity and poorest rate capability. As disclosed by density functional theory calculation and kinetics analysis, the superior potassium storage behavior of FeSe2@C is due to the high electrical conductivity and proper K+ diffusion ability of FeSe2, as well as its excellent pseudocapacitive behavior. The weak electron conductivity of FeS2 is responsible for its poor rate performance, and the large K+ diffusion barrier of FeP leads to its low reaction activity toward potassium-ion storage. Moreover, FeSe2@C also displays best rate capability among these Fe-based composites for both sodium and lithium storage.
To compare single-molecule real-time technology (SMRT) and conventional genetic diagnostic technology of rare types of thalassemia mutations, and to analyze the molecular characteristics and ...phenotypes of rare thalassemia gene variants, we used 434 cases with positive hematology screening as the cohort, then used SMRT technology and conventional gene diagnosis technology (Gap-PCR, multiple ligation probe amplification technology (MLPA), PCR-reverse dot blot (RDB) for thalassemia gene screening. Among the 434 enrolled cases, conventional technology identified 318 patients with variants (73.27%) and 116 patients without variants (26.73%), SMRT identified 361 patients with variants (83.18%), and 73 patients without variants (16.82%). The positive detection rate of SMRT was 9.91% higher than conventional technology. Combination of the two methods identified 485 positive alleles among 49 types of variant. The genotypes of 354 cases were concordant between the two methods, while 80 cases were discordant. Among the 80 cases, 76 cases had variants only identified in SMRT method, 3 cases had variants only identified in conventional method, and 1 false positive result by the traditional PCR detection technology. Except the three variants in HS40 and HBG1-HBG2 loci, which was beyond the design of SMRT method in this study, all the other discordant variants identified by SMRT were validated by further Sanger sequencing or MLPA. The hematological phenotypic parameters of 80 discordant cases were also analyzed. SMRT technology increased the positive detection rate of thalassemia genes, and detected rare thalassemia cases with variable phenotypes, which had great significance for clinical thalassemia gene screening.
The heterogeneity of meniscus cells and the mechanism of meniscus degeneration is not well understood. Here, single-cell RNA sequencing (scRNA-seq) was used to identify various meniscus cell subsets ...and investigate the mechanism of meniscus degeneration.
scRNA-seq was used to identify cell subsets and their gene signatures in healthy human and degenerated meniscus cells to determine their differentiation relationships and characterise the diversity within specific cell types. Colony-forming, multi-differentiation assays and a mice meniscus injury model were used to identify meniscus progenitor cells. We investigated the role of degenerated meniscus progenitor (DegP) cell clusters during meniscus degeneration using computational analysis and experimental verification.
We identified seven clusters in healthy human meniscus, including five empirically defined populations and two novel populations. Pseudotime analysis showed endothelial cells and fibrochondrocyte progenitors (FCP) existed at the pseudospace trajectory start. Melanoma cell adhesion molecule ((MCAM)/CD146) was highly expressed in two clusters. CD146+ meniscus cells differentiated into osteoblasts and adipocytes and formed colonies. We identified changes in the proportions of degenerated meniscus cell clusters and found a cluster specific to degenerative meniscus with progenitor cell characteristics. The reconstruction of four progenitor cell clusters indicated that FCP differentiation into DegP was an aberrant process. Interleukin 1β stimulation in healthy human meniscus cells increased CD318+ cells, while TGFβ1 attenuated the increase in CD318+ cells in degenerated meniscus cells.
The identification of meniscus progenitor cells provided new insights into cell-based meniscus tissue engineering, demonstrating a novel mechanism of meniscus degeneration, which contributes to the development of a novel therapeutic strategy.
Thalassemia is a group of common hereditary anemias that cause significant morbidity and mortality worldwide. However, precisely diagnosing thalassemia, especially rare thalassemia variants, is still ...challenging. Long-range PCR and long-molecule sequencing on the PacBio Sequel II platform utilized in this study could cover the entire HBA1, HBA2 and HBB genes, enabling the diagnosis of most of the common and rare types of thalassemia variants. In this study, 100 cases of suspected thalassemia were subjected to traditional thalassemia testing and third-generation sequencing for thalassemia genetic diagnosis. Compared with traditional diagnostic methods, an additional 10 cases of rare clinically significant variants, including 3 cases of structure variants and 7 cases of single nucleotide variations (SNVs) were identified, of which a case with - α
subtype III (- α
) was first identified and validated in the Chinese population. Other rare variants of 11.1 kb deletions (- 11.1/αα), triplicate α-globin genes (aaa
/αα) and rare SNVs have also been thoroughly detected. The results showed that rare thalassemia variants are not rare but have been misdiagnosed by conventional methods. The results further validated third-generation sequencing as a promising method for rare thalassemia genetic testing.
The regenerative capacity of neurons is limited in the central nervous system (CNS), with irreversible neuronal loss upon insult. In contrast, microglia exhibit extraordinary capacity for ...repopulation. Matsuda et al. (2019) recently reported NeuroD1-induced microglia-to-neuron conversion, aiming to provide an “unlimited” source to regenerate neurons. However, the extent to which NeuroD1 can exert cross-lineage reprogramming of microglia (myeloid lineage) to neurons (neuroectodermal lineage) is unclear. In this study, we unexpectedly found that NeuroD1 cannot convert microglia to neurons in mice. Instead, NeuroD1 expression induces microglial cell death. Moreover, lineage tracing reveals non-specific leakage of similar lentiviruses as previously used for microglia-to-neuron conversion, which confounds the microglia-to-neuron observation. In summary, we demonstrated that NeuroD1 cannot induce microglia-to-neuron cross-lineage reprogramming. We here propose rigid principles for verifying glia-to-neuron conversion. This Matters Arising paper is in response to Matsuda et al. (2019), published in Neuron.
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•Ectopic expression of NeuroD1 cannot induce microglia-to-neuron conversion in mice•Lentiviral leakage suggests labeling of cells other than microglia•Glia-to-neuron conversion by NeuroD1 should always be tested by rigid lineage tracing
NeuroD1-induced cross-lineage microglia-to-neuron conversion is hotly debated. Rao et al. demonstrate that NeuroD1 does not induce microglia-to-neuron conversion in mice. Instead, NeuroD1 triggers microglial apoptosis. Rao et al. further propose generic principles for verifying glia-to-neuron conversion.
Microplastics (MPs) are global pollutants with heightened environmental and health concerns in recent years because of their worldwide distribution across aquatic environments, ability to load ...chemical contaminants and the potential for ingestion by animals, including human. In this study, three commonly used and environmentally detected plastics, i.e. polystyrene, polyethylene, polypropylene with sizes of 550, 250 and 75 μm, plus two submicron-sized polystyrene microplastics (5 and 0.5 μm) were assessed as solid adsorbents for a prevalent UV filter, benzophenone-3 (BP-3). The affinity and process of adsorption exhibited differentials among different sizes and types of MPs. Apparent desorption of BP-3 from MPs under simulated gastrointestinal conditions was not significantly enhanced, which might be due to the presence of the enzyme proteins, indicating potential risk of the contaminants carried by MPs. The desorption of BP-3 from MPs was affected by the size, type of MPs and the components of the gastrointestinal fluid.
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•The adsorption of Benzophenone-3 (BP-3) on microplastics exhibited significant microplastics type and size differentials.•Desorption of BP-3 from microplastics under simulated human gastrointestinal conditions was assessed.•The enzyme proteins pepsin and trypsin may result in a declined apparent desorption of BP-3 from microplastics.
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