Comprehensive assessment of copper's effect on marine organisms under ocean acidification and warming in the 21st century

Copper (Cu) has sparked widespread global concern as one of the most hazardous metals to aquatic animals. Ocean acidification (OA) and warming (OW) are expected to alter copper's bioavailability based on pH and temperature-sensitive effects; research on their effects on copper on marine organisms is still in its infancy. Therefore, under representative concentration pathways (RCP) 2.6, 4.5, and 8.5, we used the multiple linear regression-water quality criteria (MLR-WQC) method to assess the effects of OA and OW on the ecological risk posed by copper in the Ocean of East China (OEC), which includes the Bohai Sea, Yellow Sea, and East China Sea. The results showed that there was a positive correlation between temperature and copper toxicity, while there was a negative correlation between pH and copper toxicity. The short-term water quality criteria (WQC) values were 1.53, 1.41, 1.30 and 1.13 μg·L-1, while the long-term WQC values were 0.58, 0.48, 0.40 and 0.29 μg·L-1 for 2020, 2099-RCP2.6, 2099-RCP4.5 and 2099-RCP8.5, respectively. Cu in the OEC poses a moderate ecological risk. Under the current copper exposure situation, strict intervention (RCP2.6) only increases the ecological risk of copper exposure by 20 %, and no intervention (RCP8.5) will increase the ecological risk of copper exposure by nearly double. The results indicate that intervention on carbon emissions can slow down the rate at which OA and OW worsen the damage copper poses to marine creatures. This study can provide valuable information for a comprehensive understanding of the combined impacts of climate change and copper on marine organisms.

Comprehensive effects of salinity, dissolved organic carbon and copper on mortality, osmotic regulation and bioaccumulation of copper in Oryzias melastigma

Cu, as an essential and toxic element, has gained widespread attention. Both salinity and dissolved organic carbon (DOC) are known to influence Cu toxicity in marine organisms. However, the intricate interplay between these factors and their specific influence on Cu toxicity remains ambiguous. So, this study conducted toxicity tests of Cu on Oryzias melastigma. The experiments involved three salinity levels (10, 20, and 30 ppt) and three DOC levels (0, 1, and 5 mg/L) to comprehensively investigate the underlying mechanisms of toxicity. The complex toxic effects were analyzed by mortality, NKA activity, net Na+ flux and Cu bioaccumulation in O. melastigma. The results indicate that Cu toxicity is notably influenced by both DOC and salinity. Interestingly, the discernible variation in Cu toxicity across different DOC levels diminishes as salinity levels increase. The presence of DOC enhances the impact of salinity on Cu toxicity, especially at higher Cu concentrations. Additionally, Visual MINTEQ was utilized to elucidate the chemical composition of Cu, revealing that DOC had a significant impact on Cu forms. Furthermore, we observed that fluctuations in salinity lead to the inhibition of Na+/K+-ATPase (NKA) activity, subsequently hindering the inflow of Na+. The effects of salinity and DOC on the bioaccumulation of copper were not significant. The influence of salinity on Cu toxicity is mainly through its effect on the osmotic regulation and biophysiology of O. melastigma. Additionally, DOC plays a crucial role in the different forms of Cu. Moreover, DOC-Cu complexes can be utilized by organisms. This study contributes to understanding the mechanism of copper's biological toxicity in intricate marine environments and serves as a valuable reference for developing marine water quality criteria for Cu.

A comprehensive review of the effects of salinity, dissolved organic carbon, pH, and temperature on copper biotoxicity: Implications for setting the copper marine water quality criteria

In recent years, there has been a growing concern about the ecological hazards associated with copper, which has sparked increased interest in copper water quality criteria (WQC). The crucial factors affecting the bioavailability of copper in seawater are now acknowledged to be salinity, dissolved organic carbon (DOC), pH, and temperature. Research on the influence of these four water quality parameters on copper toxicity is rapidly expanding. However, a comprehensive and clear understanding of the relevant mechanisms is currently lacking, hindering the development of a consistent international method to establish the seawater WQC value for copper. As a response to this knowledge gap, this study presents a comprehensive summary with two key focuses: (1) It meticulously analyzes the effects of salinity, DOC, pH, and temperature on copper toxicity to marine organisms. It takes into account the adaptability of different species to salinity, pH and temperature. (2) Additionally, the study delves into the impact of these four water parameters on the acute toxicity values of copper on marine organisms while also reviewing the methods used in establishing the marine WQC value of copper. The study proposed a two-step process: initially zoning based on the difference of salinity and DOC, followed by the establishment of Cu WQC values for different zones during various seasons, considering the impacts of water quality parameters on copper toxicity. By providing fundamental scientific insights, this research not only enhances our understanding and predictive capabilities concerning water quality parameter-dependent Cu toxicity in marine organisms but also contributes to the development of copper seawater WQC values. Ultimately, this valuable information facilitates more informed decision-making in marine water quality management efforts.

Black phosphorus-incorporated novel Ti-12Mo-10Zr implant for multimodal treatment of osteosarcoma

The repair and reconstruction of large bone defects after bone tumor resection is still a great clinical challenge. At present, orthopedic implant reconstruction is the mainstream treatment for repairing bone defects. However, according to clinical feedback, local tumor recurrence and nonunion of bone graft are common reasons leading to the failure of bone defect repair and reconstruction after bone tumor resection, which seriously threaten the physical and mental health of patients. On this basis, here the self-developed low modulus Ti-12Mo-10Zr alloy (TMZ) was chosen as substrate material. To improve its biological activity and osteointegration, calcium, oxygen, and phosphorus co-doped microporous coating was prepared on TMZ alloy by microarc oxidation (MAO). Then, black phosphorus (BP) nanosheets were incorporated onto MAO treated TMZ alloy to obtain multifunctional composites. The obtained BP-MAO-TMZ implant exhibited excellent photothermal effects and effective ablation of osteosarcoma cancer cells under the irradiation of 808 nm near infrared laser, while no photothermal or therapeutic effects were observed for TMZ alloy. Meanwhile, the structure/component bionic coating obtained after MAO treatment as well as the P-driven in situ biomineralization performance after incorporation of BP nanosheets endowed BP-MAO-TMZ implant with synergistic promoting effect on MC3T3-E1 osteoblasts' activity, proliferation and differentiation ability. This study is expected to provide effective clinical solutions for problems of difficult bone regeneration and tumor recurrence after tumor resection in patients with bone tumors and to solve a series of medical problems such as poor prognosis and poor postoperative quality of patients life with malignant bone tumors.

Comparison of the retinal microvasculature between compressive and glaucomatous optic neuropathy

PURPOSE

To compare the patterns of retinal microvasculature change in the peripapillary and macular region between compressive optic neuropathy (CON) and glaucomatous optic neuropathy (GON), and to assess the ability of optical coherence tomography angiography (OCTA) in differentiating the two conditions.

METHODS

This cross-sectional study included 108 participants (108 eyes), 36 with CON, 36 with GON, and 36 healthy controls. The CON and GON eyes were matched by the average peripapillary retinal nerve fiber layer (pRNFL) thickness (1:1). Optical coherence tomography (OCT) and OCTA were performed to compare the structural and vascular change of the peripapillary and macular region between groups.

RESULTS

Both CON and GON eyes showed more severe structural and vascular damage than the control eyes. The CON eyes had lower pRNFL thickness than the GON eyes in the temporal and nasal quadrants, and thicker pRNFL thickness in the inferior quadrant. The average GCC thickness did not differ between the two groups. The peripapillary vessel density of the CON group was significantly higher in the inferior sectors than that of the GON group. In the macular region, the CON group had significantly higher vessel density in the whole image, the temporal sector in parafovea region, and the temporal, superior, and inferior sectors in perifovea region.

CONCLUSION

To a similar degree of structural damage, CON had less retinal vascular impairment than GON, especially in the macular region, and the significance of the finding needs further evaluation.

Multiple isotopes reveal the driving forces of nitrogen cycling from freshwater to brackish water

Rivers play a crucial role in global nitrogen (N) cycling, but revealing the driving mechanism of N cycling remains challenging because of the complex natural background gradients. The Qiantang River Basin provides an opportunity to elucidate the driving mechanism due to the complex climatic and hydrological conditions. In this study, the multiple stable isotopes suggested that the conservative mixing of two end members was insufficient to explain the complex behavior of N in both seasons. In-soil processes were the primary N cycling processes that controlled riverine N loading during the wet season, whereas in-stream N biological transformation processes (nitrification and assimilation) were more prevalent during the dry season. The results of MixSIAR revealed that soil sources (soil N and N fertilizer) contributed the most to NO3- during the wet season, accounting for 64.3 %, followed by manure and sewage (31.6 %) and atmospheric precipitation (4.1 %). During the dry season, manure and sewage were the predominant contributors to NO3- (52.1 %), followed by soil N (26.6 %), N fertilizer (18.8 %), and atmospheric precipitation (2.5 %). The relationships between d-excess and δ15N-NH4+ or δ15N-NO3- suggested that both climatic and hydrological conditions would be the driving forces regulating the N transportation and transformation in this basin, leading to the high spatiotemporal heterogeneity in N loading and isotopic compositions. In the wet season, precipitation patterns served as the primary driving forces regulating in-soil biological processes and soil leaching. While the hydrological conditions, especially water residence time, were the crucial factors controlling in-stream biological processes during the dry season. This study elucidates N sources, biotransformation processes, and their driving forces from freshwater to brackish water, which has applications for understanding the N fate from terrene to ocean.

Platinum based theranostics nanoplatforms for antitumor applications

Platinum (Pt) based nanoplatforms are biocompatible nanoagents with photothermal antitumor performance, while exhibiting excellent radiotherapy sensitization properties. Pt-nanoplatforms have extensive research prospects in the realm of cancer treatment due to their highly selective and minimally invasive treatment mode with low damage, and integrated diagnosis and treatment with image monitoring and collaborative drug delivery. Platinum based anticancer chemotherapeutic drugs can kill tumor cells by damaging DNA through chemotherapy. Meanwhile, Pt-nanoplatforms also have good electrocatalytic activity, which can mediate novel electrodynamic therapy. Simultaneously, Pt(II) based compounds also have potential as photosensitizers in photodynamic therapy for malignant tumors. Pt-nanoplatforms can also modulate the immunosuppressive environment and synergistically ablate tumor cells in combination with immune checkpoint inhibitors. This article reviews the research progress of platinum based nanoplatforms in new technologies for cancer therapy, starting from widely representative examples of platinum based nanoplatforms in chemotherapy, electrodynamic therapy, photodynamic therapy, photothermal therapy, and immunotherapy. Finally, multimodal imaging techniques of platinum based nanoplatforms for biomedical diagnosis are briefly discussed.

[Spatiotemporal Variation Characteristics of Main Pollutant Fluxes in the Yangtze River Basin from 2017 to 2020]

Based on the monitoring data of various pollutants at important water system points in the Yangtze River Basin from 2017 to 2020, research on the flux change law of the main and tributary water systems in the Yangtze River Basin was carried out at the spatiotemporal scale, and the spatial change response, interannual change trend, and flux correlation analysis were analyzed from the aspects of water quantity, quality, and flux so as to reveal the spatial-temporal contribution characteristics of pollutant flux in the upper, middle, and lower reaches of the Yangtze River Basin. The results showed that over the past four years, the concentration of major pollutants in the Yangtze River Basin showed an overall downward trend. The concentration of total phosphorus (TP) and ammonia (NH+4-N) decreased significantly. The concentration of total nitrogen (TN) and total phosphorus (TP) in the main stream gradually increased from west to east. The annual concentration of permanganate index in the upper, middle, and lower reaches decreased by 18.5%, 16.0%, and 14.0%, respectively, from 2017 to 2020, with the highest decline in the upper reaches. The four-year average value of the spatial distribution of runoff significantly increased from 466×108 m3 to 9923×108 m3. The two lake basins in the tributary river lake water system had the largest contribution to the water volume. The fluxes of permanganate index, total phosphorus (TP), and total nitrogen (TN) among the main pollutants showed an annual increase and then decrease trend. The pollutant fluxes in the Minjiang River, Tuojiang River, Jialing River, and the middle reaches of the two lakes contributed greatly to the river inflow. There were differences in fluxes in different regional water environments. The results of correlation and hierarchical cluster analysis showed that the permanganate index and TP fluxes were highly significantly correlated with water volume, and there was a significant correlation between biochemical oxygen demand (BOD5) and total nitrogen (TN), total phosphorus (TP), and chemical oxygen demand (COD). The main pollutants showed strong differences in the flood and non-flood periods and had a significant response in the flood season from July to September. The research results can provide scientific basis and theoretical support for the integrated management and precise prevention and control of the aquatic environment in the Yangtze River Basin.

Exploration of the factors that influence total phosphorus in surface water and an evaluation of surface water vulnerability based on an advanced algorithm and traditional index method

Due to the continuous influence of human activities, phosphorus pollution in surface water has become a persistent problem that needs to be addressed since phosphorous entails certain risks and degrees of damage to ecosystems and humans. The presence and accumulation of total phosphorus (TP) concentrations in surface waters is the result of a combined effect of many natural and anthropogenic factors, and it is often difficult to intuitively identify the individual importance of each factor in regard to the pollution of the aquatic environment. Considering these issues, this study provides a new methodology to better understand the vulnerability of surface water to TP pollution and the factors that influence TP pollution through the application of two modeling approaches. This includes the boosted regression tree (BRT), an advanced machine learning method, and the traditional comprehensive index method (CIM). Different factors, such as natural variables (including slope, soil texture, normalized difference vegetation index (NDVI), precipitation, and drainage density) and point and nonpoint source anthropogenic factors were included to model the vulnerability of surface water to TP pollution. Two methods were used to produce a vulnerability map of surface water to TP pollution. Pearson correlation analysis was used to validate the two vulnerability assessment methods. The results showed that BRT was more strongly correlated than CIM. In addition, the importance ranking results showed that slope, precipitation, NDVI, decentralized livestock farming and soil texture had a greater influence on TP pollution. Industrial activities, scale livestock farming and population density, which are all contributing sources of pollution, were all relatively less important. The introduced methodology can be used to quickly identify the area most vulnerable to TP pollution and to develop problem specific adaptive policies and measures to reduce the damage from TP pollution.

Use of non-linear multiple regression models for setting water quality criteria for copper: Consider the effects of salinity and dissolved organic carbon

Cu pollution is a global concern because of its high toxicity and persistence. Few investigations have been conducted on the effects of salinity and dissolved organic carbon (DOC) on Cu toxicity and water quality criteria (WQC). To analyze their impact on the WQC of Cu, non-linear multiple regression (NLMR) models based on salinity and DOC were constructed. The NLMR models demonstrated that when salinity increased, the toxicity values for Cu on fish, mollusca, rotifer, and echinodermata first increased and then declined, whereas those for arthropoda and algae increased. These findings demonstrate that salinity has a substantial impact on Cu toxicity, primarily owing to changes in physiological activity. The original and corrected WQC values in the upper, middle, and outer regions of the Yangtze Estuary were derived based on the species sensitivity distribution method. These values were 1.49, 3.49, 8.86, and 0.87 μg·L^-1. An important finding was that lower Cu concentrations in the outer areas posed the highest ecological risk owing to the effects of salinity and DOC. NLMR models are applicable to other coastal areas worldwide. This provides valuable information for the establishment of an accurate and protective estuary for Cu-related WQC.

Environmentally adaptive polysaccharide-based hydrogels and their applications in extreme conditions: A review

Polysaccharide hydrogels are one of the most promising hydrogel materials due to their inherent characteristics, including biocompatibility, biodegradability, renewability, and easy modification, and their structure and functional designs have been widely researched to adapt to different application scenarios as well as to broaden their application fields. As typical wet-soft materials, the high water content and water-absorbing ability of polysaccharide-based hydrogels (PHs) are conducive to their wide biomedical applications, such as wound healing, tissue repair, and drug delivery. In addition, along with technological progress, PHs have shown potential application prospects in some high-tech fields, including human-computer interaction, intelligent driving, smart dressing, flexible sensors, etc. However, in practical applications, due to the poor ability of PHs to resist freezing below zero, dehydration at high temperature, and acid-base/swelling-induced deformation in a solution environment, they are prone to lose their wet-soft peculiarities, including structural integrity, injectability, flexibility, transparency, conductivity and other inherent characteristics, which greatly limit their high-tech applications. Hence, reducing their freezing point, enhancing their high-temperature dehydration resistance, and improving their extreme solution tolerance are powerful approaches to endow PHs with multienvironmental adaptability, broadening their application areas. This report systematically reviews the study advances of environmentally adaptive polysaccharide-based hydrogels (EAPHs), comprising anti-icing hydrogels, high temperature/dehydration resistant hydrogels, and acid/base/swelling deformation resistant hydrogels in recent years. First, the construction methods of EAPHs are presented, and the mechanisms and properties of freeze-resistant, high temperature/dehydration-resistant, and acid/base/swelling deformation-resistant adaptations are simply demonstrated. Meanwhile, the features of different strategies to prepare EAPHs as well as the strategies of simultaneously attaining multienvironmental adaptability are reviewed. Then, the applications of extreme EAPHs are summarized, and some meaningful works are well introduced. Finally, the issues and future outlooks of PH environment adaptation research are elucidated.

OONO-/MMP2/MMP9 pathway-mediated apoptosis of porcine granulosa cells is associated with DNA damage

In brief

The apoptosis of granulosa cells (GCs) is the main reason for porcine follicular atresia. This study provides a novel mechanism for peroxynitrite anion-mediated GC apoptosis and follicular atresia in porcine ovary.

Abstract

Granulosa cells play a crucial role in the development of follicles, and their cell apoptosis in the porcine ovary is a major contributor to follicular atresia. Here, we provide a new mechanism for follicular atresia by describing a crucial mechanism by which peroxynitrite anion (OONO-) may cause GC death. We discovered that nitric oxide, oxidative stress level, and OONO- were positively correlated with porcine follicular atresia, which was accompanied by high expression of matrix metalloproteinase 2 (MMP2) and MMP9. We created a model of OONO--induced apoptosis in GCs and discovered that OONO- could boost the expression of MMP2 and MMP9 and increase the expression of pro-apoptotic proteins and DNA damage. Furthermore, by inhibiting the activities of MMP2 and MMP9, we found that SB-3CT (a specific inhibitor for MMP2 and MMP9) alleviated the decrease in cell survival rates and DNA damage caused by OONO-, which may have been impacted by reducing the cleavage of PARP1 by MMP2 and MMP9. Therefore, our findings imply that OONO- can cause DNA damage to GCs, participating in mediating the expression of pro-apoptotic proteins and inhibiting DNA repair by preventing the activity of PARP1 through MMP2 and MMP9. These results help explain how OONO-/MMP2/MMP9 affects porcine follicular atresia and GC apoptosis.

Discriminating Between Compressive Optic Neuropathy With Glaucoma-Like Cupping and Glaucomatous Optic Neuropathy Using OCT and OCTA

Purpose

To discriminate between compressive optic neuropathy with glaucoma-like cupping (GL-CON) and glaucomatous optic neuropathy (GON) by comparing the peripapillary retinal nerve fiber layer (pRNFL) thickness and retinal microvasculature using optical coherence tomography (OCT) and optical coherence tomography angiography (OCTA).

Methods

In this retrospective cross-sectional study, OCT scans were performed on 28 eyes of GL-CON, 34 eyes of GON, and 41control eyes to determine the pRNFL thickness, ganglion cell complex thickness, and cup/disc ratio. OCTA scans were conducted for 12 eyes of GL-CON, 15 eyes of GON, and 15 control eyes to measure the vessel density of the peripapillary and macular areas. Analysis of covariance was used to perform the comparisons, and the area under the curve was calculated.

Results

The GON eyes had a significantly thinner pRNFL in the inferior quadrant and greater vertical cup/disc ratio than the GL-CON eyes. In the radial peripapillary capillary segment, the vessel density of the GON in the inferior sectors was significantly lower than in the GL-CON. The superficial macular vessel density in the whole-image, peritemporal, perinasal, and peri-inferior sectors was significantly smaller in the GON group than in the GL-CON group. The best parameter for discriminating between GL-CON and GON was the superficial macular vessel density in the peritemporal sector.

Conclusions

GL-CON eyes showed a characteristic pattern of pRNFL and retinal microvascular changes.

Translational Relevance

GL-CON can be effectively distinguished from GON by detecting the alterations in the pRNFL and retinal microvasculature using OCT and OCTA.

Dietary curcumin supplementation relieves hydrogen peroxide-induced testicular injury by antioxidant and anti-apoptotic effects in roosters

This study was aimed to investigate the effects of dietary curcumin supplementation on the hydrogen peroxide (H₂O₂)-induced testicular oxidative damage in breeder roosters. Thirty-two 20-week roosters were randomly divided into four groups: (1) basal diet (CON); (2) basal diet with H₂O₂ challenge (H₂O₂); (3) basal diet with 200 mg/kg curcumin (CUR); (4) basal diet with 200 mg/kg curcumin and H₂O₂ challenge (CUR + H₂O₂). The trial lasted for 8 weeks, H₂O₂ challenged groups got an intraperitoneal injection of H₂O₂ at the 50 and 53 days, while the CON and CUR groups received an injection of saline. The results showed that dietary curcumin supplementation significantly decreased abnormal sperm rates in the semen, notably improved seminiferous tubules, increased testis scores, and serum testosterone levels. Curcumin supplementation could also ameliorate the redox damage caused by H₂O₂, by enhancing the capacities of antioxidant enzymes (CAT, GSH-Px, SOD, and T-AOC), and reducing MDA levels. In addition, curcumin normalized the H₂O₂-induced negative effects, which included downregulations in spermatogenesis-related genes (STAR, HSD3-β1, SYCP3, AKT1) and antioxidant genes (HMOX-1, NQO-1), reduced protein expressions of Nrf2, PCNA, and Bcl-2, and increased protein expressions of Caspase 3 and Bax. Moreover, H₂O₂-induced decreased mRNA expressions of EIF2AK3, Caspase3, and BCL-2 were all reversed by dietary curcumin supplementation. In summary, dietary curcumin supplementation could relieve H₂O₂-induced oxidative damage and reproduction decline through the Nrf2 signaling pathway and anti-apoptotic effects in roosters.

Improvement in water pollution control alters nutrient stoichiometry of Guanting Reservoir near Beijing, North China

Significant improvement in wastewater treatment is the most effective way for eutrophication control, especially in semiarid regions. However, its effect on the nutrient status and stoichiometry of the receiving water body has remained poorly considered and understood at broad temporal scales. Taking Guanting Reservoir (GR) in Hebei-Beijing (P. R. China) as an example, we present a study that links a continuous monitoring dataset for GR with corresponding estimates of human-induced nutrient discharges in its watershed from the year 2006 to 2019. We find that current GR belongs to strict P limitation and the faster decrease of TP than TN concentrations and continuous increase of TN/TP mass ratios in GR are attributed to the water restoration investment-induced declining of nutrient loadings. The improved municipal wastewater treatment capacity is mainly responsible for these significant changes, due to the higher removal efficiency of TP than TN in municipal wastewater. Given the potential ecological impact on aquatic biodiversity as well as ecosystem function of changes in TN/TP ratios and higher retention rate of TP (97.4%) compared with TN (93.1%) in GR, our findings highlight that future strategy for water pollution control should not only concentrate on more nutrient reduction efficiencies but attach importance to their stoichiometric balance to reduce the potential risk of phytoplankton blooms and toxin production during the water quality recovery of lakes or reservoirs.

Salinity-dependent aquatic life criteria of inorganic mercury in coastal water and its ecological risk assessment

Mercury (Hg) is one of the most toxic pollutants to aquatic organisms. The influence of salinity on Hg toxicity, an important factor restricting the development of global marine aquatic life criteria (ALC), is unclear. Therefore, mercury toxicity data were corrected based on salinity using the aggregate slope method, and the ALC values were derived. Short-term aquatic life criteria (SALC) and long-term aquatic life criteria (LALC) were derived using the species sensitivity distribution method based on Log-logistic, Log-normal, Burr III, Gumbel, and Weibull models. The hazard quotient (HQ) and joint probability curve (JPC) methods were used to evaluate the ecological risk of Hg in the coastal waters of China. The results showed that the SALC and LALC of Hg in the coastal waters of China were 2.21 and 0.54 μg/L. The toxicity data and salinity were positively correlated for Chordate and Arthropoda and negatively correlated for Mollusca. The SALC values increased by approximately 75%, with salinities ranging from 10 to 20 ppt. A slight peak in the SALC at mid-salinities was also observed. The ecological risk assessment of Hg in China's coastal waters showed that attention should be paid to Hg pollution in the Bohai Sea and East China Sea, especially the ecological risk of Hg to crustacean organisms. This study could promote the development of water quality criteria for coastal waters and provide a technical reference for mercury management in the coastal waters of China.

Identification of nitrogen sources and cycling along freshwater river to estuarine water continuum using multiple stable isotopes

Nitrogen (N) transport from terrene to river water is a major source of N in estuarine water, contributing to eutrophication, harmful algal blooms and hypoxia. However, there is a lack of holistic and systematic research on N sources and transformation in the freshwater river-estuarine water continuum. In this study, multiple stable isotope signatures of nitrate (δ¹⁵N-NO₃^-, δ¹⁸O-NO₃^-), ammonium (δ¹⁵N-NH₄⁺), and suspended particulate nitrogen (δ¹⁵N-PN) were employed to differentiate the sources and transformations of N and calculate the proportional contribution of NO₃^- sources by Bayesian model in Qiantang River (QTR)-Hangzhou Bay (HZB) during the dry season. The results showed that: (1) Evidences from isotopic signatures suggested the occurrence of N transformation instead of conservation mixing. (2) Negative correlations between the δ¹⁵N-NO₃^- and δ¹⁵N-NH₄⁺, the relationships between δ¹⁵N-NO₃^- and NO₃^--N concentrations, and smaller δ¹⁸O-NO₃^- values were found in almost all surface water, indicating that nitrification was the dominant N transformation. (3) In addition to the nitrification evidence, significant correlations between δ¹⁵N-PN and δ¹⁵N-NH₄⁺ revealed that assimilation and nitrification jointly affected the N transformation in the QTR's upstream, midstream and lower tributaries, which are unaffected or less affected by tides. (4) The lack of a relationship between δ¹⁵N-NO₃^- and δ¹⁸O-NO₃^- or ln(NO₃^-) indicated that denitrification was weakened in all surface waters. (5) Qualitative identification of N pollution sources and quantitative calculation of NO₃^--N potential sources revealed that sewage was the dominant source of N in the QTR and the HZB, while the internal nitrification was also important factor in determining N levels. This study provided evidence to further understand the sources, transport, and transformation of N in the river-estuary continuum, which deepens the understanding of the land-ocean integrated management of N contaminant.

Highly stretchable, self-healing elastomer hydrogel with universal adhesion driven by reversible cross-links and protein enhancement

Engineered hydrogels with excellent mechanical properties and multi-functionality have great potential as soft electronic skins, tissue substitutes and flexible robotic joints. However, it has been a challenge to construct multifunctional hydrogels, especially when integrating high stretchability, toughness and strength, low hysteresis, good self-healing and adhesion abilities into a hydrogel system simultaneously. Here, we successfully developed a structural hydrogel composed of a reversible covalently cross-link-based poly-N-(2-hydroxyethyl)acrylamide (PHEMAA) network and available plastically deformable casein micelles. Such a design enabled the reversible covalent cross-links and casein micelles to enhance energy dissipation and toughen the PHEMAA/casein hybrid hydrogel synergistically. More importantly, the hydrogel could respond to the imposed strains reversibly by cross-link and micelle deformation induced-network reconstitution, which led to low hysteresis of the hydrogels. The recoverable gel networks still exhibited their effects on energy dissipation at the stress-focused area, endowing the hydrogels with fatigue resistance. As a result, the hydrogels exhibited a compressive strength of 36.5 MPa, high stretchability (1460%), high toughness (∼5.98 MJ m^-3), low hysteresis (<30%) and fatigue resistance with almost completely overlapped hysteresis curves during 10 loading cycles. In addition, the introduction of casein micelles and reversible covalent bonding endowed the elastomer hydrogels with high adhesivity, self-healing abilities and biocompatibility.

Chemical characteristics analysis of automobile exhaust particles and the method for evaluating its ecological effect

Automobile exhaust has become the main source of atmospheric particulate matter with the increase in the number of automobiles. Automobile exhaust particles (AEPs) discharged into the atmosphere can enter the aquatic environment through atmospheric deposition, rain runoff, leaching, drainage water and urban sewage and further affect aquatic organisms. However, there is no comprehensive theory and method to evaluate the ecological effects of AEPs on aquatic environment. The new European driving cycle (NEDC) and the world harmonized light-duty test cycle (WLTC) were used to analyze the ecotoxicity of AEPs. The SUV gasoline, SUV hybrid and sedan gasoline under WLTC were used for further analysis. The chemical characteristics of AEPs were analyzed, and the ecotoxicity of AEPs on aquatic organisms was studied with Vibrio fischeri and Danio rerio as test organisms. The ecological effect of AEPs was studied through species sensitivity distribution based on interspecies correlation estimation (ICE) models. The results showed that (ⅰ) polycyclic aromatic hydrocarbons (PAHs) were the main organic substances in AEPs. The total concentrations of PAHs in AEPs measured under the NEDC and WLTC were 237.4 and 159.8 mg kg^-1, respectively, and the EC₅₀ values for V. fischeri measured under the NEDC and WLTC were 42.02 and 47.05 mg L^-1, respectively. (ⅱ) Total heavy metal concentrations in AEPs from SUV gasoline, SUV hybrid, and sedan gasoline were 197.52, 104.86, and 89.68 mg kg^-1, respectively, and the LC₅₀ values for D. rerio were 3.22, 4.46 and 5.62 mg L^-1. Cu and Mn were the main toxic heavy metals in AEPs. (ⅲ) The PNEC values of AEPs from SUV gasoline, SUV hybrid and sedan gasoline were 0.57, 0.83 and 1.02 mg L^-1, respectively. This exploratory study can provide technical information on water ecological safety assessment for determining the impact of AEPs on the surface water environment and for further improving automobile exhaust emission standards.

Applications of phase change materials in smart drug delivery for cancer treatment

Phase change materials (PCMs) are materials that are stimulated by the external enthalpy change (temperature) to realize solid-liquid and liquid-solid phase transformation. Due to temperature sensitivity, friendly modification, and low toxicity, PCMs have been widely used in smart drug delivery. More often than not, the drug was encapsulated in a solid PCMs matrix, a thermally responsive material. After the trigger implementation, PCMs change into a solid-liquid phase, and the loading drug is released accordingly. Therefore, PCMs can achieve precise release control with different temperature adjustments, which is especially important for small molecular drugs with severe side effects. The combination of drug therapy and hyperthermia through PCMs can achieve more accurate and effective treatment of tumor target areas. This study briefly summarizes the latest developments on PCMs as smart gate-keepers for anti-tumor applications in light of PCMs becoming a research hot spot in the nanomedicine sector in recent years.

Single-Cell Transcriptomic Atlas of Gingival Mucosa in Type 2 Diabetes

The oral gingival barrier is a constantly stimulated and dynamic environment where homeostasis is often disrupted, resulting in inflammatory periodontal diseases. Type 2 diabetes (T2D) has been reported to be associated with gingival barrier dysfunction, but the effect and underlying mechanism are inconclusive. Herein, we performed single-cell RNA sequencing (scRNA-seq) of gingiva from leptin receptor-deficient mice (db/db) to examine the gingival heterogeneity in the context of T2D. Periodontal health of control mice is characterized by populations of Krt14⁺-expressing epithelial cells and Col1a1⁺-fibroblasts mediating immune homeostasis primarily through the enrichment of innate lymphoid cells. The db/db gingiva exhibited decreased epithelial/stromal ratio and dysfunctional barrier. We further observed stromal, particularly fibroblast immune hyperresponsiveness, linked to the recruitment of myeloid-derived cells at the db/db gingiva. Both scRNA-seq and histological analysis suggested the inflammatory signaling between fibroblasts and neutrophils as a potential driver of diabetes-induced periodontal damage. Notably, the "immune-like" stromal cells were wired toward the induction of gingival γδ T hyperresponsiveness in db/db mice. Our work reveals that the "immune-like" fibroblasts with transcriptional diversity are involved in the innate immune homeostasis at the diabetic gingiva. It highlights a potentially significant role of these cell types in its pathogenesis.

[MiR-744-5p inhibits the proliferation, invasion, and migration of clear-cell renal cell carcinoma cells by targeting CCND1]

OBJECTIVE

To explore the role of miR-744-5p/CCND1 axis in clear-cell renal cell carcinoma (ccRCC).

METHODS

We examined the expression levels of miR-744-5p in 65 pairs of ccRCC and adjacent tissue specimens and in 5 ccRCC cell lines and human renal tubular epithelial (HK2) cells using qRT-PCR. The ccRCC cell lines 786-O and OSRC2 were transfected with miR-744-5p mimic, CCND1 mimic, or their negative control mimics, and the changes in cell proliferation, migration, and invasion were evaluated with CCK-8, wound healing, and Transwell assays. The downstream target molecules of miR-744-5p were predicted by bioinformatics analysis, and the expression level of CCND1 in ccRCC cells was verified by qRT-PCR and Western blotting. The relationship between miR-744-5p and CCND1 was further validated by dual luciferase reporter assay, and the role of the miR-744-5p/CCND1 axis in ccRCC was explored by rescue experiments.

RESULTS

MiR-744-5p was significantly downregulated in ccRCC tissues and cell lines (all P < 0.05), and its overexpression inhibited the proliferation, migration, and invasion of ccRCC cells (all P < 0.05). Bioinformatics analysis and dual luciferase reporter assay showed that CCND1 was a downstream target of miR-744-5p. The results of rescue experiments showed that upregulation of CCND1 could partially reverse the inhibitory effect of miR-744-5p overexpression on ccRCC cell proliferation, migration, and invasion (all P < 0.05).

CONCLUSION

MiR-744-5p inhibits the malignant phenotype of ccRCC cells by targeting CCND1, and the miR-744-5p/CCND1 axis may be a novel target for diagnosis and treatment of ccRCC.

Transdermal Delivery of Indirubin-Loaded Microemulsion Gel: Preparation, Characterization and Anti-Psoriatic Activity

Psoriasis is an immune disease caused by rapid and incomplete differentiation of skin basal cells. Natural products such as indirubin have historically served as excellent sources for the treatments of psoriasis. However, the poor solubility and bioavailability due to its plane and rigid crystal structure, which limits its efficacy. Herein, to improve the efficacy of indirubin, a hydrogel-based microemulsion drug delivery system was developed for transdermal delivery. The mean droplet size of the optimized microemulsion was 84.37 nm, with a polydispersity index (PDI) less than 0.2 and zeta potential value of 0~−20 mV. The transdermal flux and skin retention of indirubin at 24 h were 47.34 ± 3.59 μg/cm² and 8.77 ± 1.26 μg/cm², respectively. The optimized microemulsion was dispersed in carbomer 934 hydrogel to increase the consistency. The indirubin-loaded microemulsion gel was tested on an imiquimod-induced psoriasis mouse model. Results showed that this preparation can improve psoriasis symptoms by down-regulating the expression of IL-17A, Ki67, and CD4⁺T. This experiment provides great scalability for researchers to treat psoriasis, avoid first-pass effects, and increase the concentration of targeted drugs.

[Analysis of molecular and clinical characteristics of carbapenem-resistant hypervirulent Klebsiella pneumoniae in the intensive care unit]

To investigate the carbapenemases distribution of carbapenem-resistant Klebsiella pneumoniae (CRKP) in the intensive care unit, and the clinical characteristics between carbapenem-resistant hypervirulent Klebsiella pneumoniae (CR-hvKP) and carbapenem-resistant non-hypervirulent Klebsiella pneumoniae (CR-non-hvKP) were compared. A total of 53 non-repetitive CRKP strains isolated from 49 patients in the intensive care unit of the Second Affiliated Hospital of Xi'an Jiaotong University from May 2020 to March 2021 were retrospectively studied. The carbapenemase inhibitor enhancement test was used for screening carbapenemase-producing strains, and the string test was carried out to screen the hypermucoviscosity phenotype. Using PCR to detect five main carbapenemase genes (bla_KPC-2, bla_NDM, bla_IMP , bla_VIM and bla_OXA-48-like), common serotype (K1 and K2) and virulence gene (rmpA and iutA). Treated the strains with both rmpA and iutA genes as hypervirulent Klebsiella pneumonia (hvKP), and the whole genome sequencing of CR-hvKP was completed. At the same time, the clinical data of 49 patients were sorted out, and the differences in clinical characteristics of CR-hvKP and CR-non-hvKP infected patients were compared using the independent sample t test, Mann-Whitney U test, chi-square test or Fisher's exact probability test. CRKP isolated from the intensive care unit were extensively drug resistance and still had a good sensitivity to polymyxin B and tigecycline. Producing carbapenemases were the main resistance mechanism of CRKP (52/53, 98.1%). Of the 53 CRKP strains, except for 1strain that did not detect carbapenemase, at least one carbapenemase resistance gene was detected in the remaining 52 CRKP strains, of which 45 strains carried an enzyme, including 36 bla_KPC-2 (36/53, 67.9%), 8 bla_NDM (8/53, 15.1%), 1 bla_IMP (1/53, 1.9%), and 7 strains carried with both bla_KPC-2 and bla_NDM (7/53, 13.2%). String test and virulence gene showed that 7 CR-hvKP strains (13.2%) were detected in 53 CRKP strains, and two of which were hypermucoviscosity phenotype. Sequencing results revealed that CR-hvKP were mainly ST11 type. Almost all patients with CR-hvKP infection were over 60 years old (7/7), with invasive treatment (7/7), pulmonary infection with hypermucoviscosity phenotype (2/7) and high mortality (5/7); and the percentage of neutrophils in patients with CR-hvKP infection (86.44±4.70) % was higher than those patients with CR-non-hvKP infection (78.90±19.15) %, the difference was statistically significant (t=-2.225, P=0.032). The CR-hvKP strains in the intensive care unit mainly produced KPC-2 enzyme, with K2 capsular serotype and ST11 type. It is necessary to strengthen the monitoring and control of the CR-hvKP strain to prevent the co-evolution of drug-resistant and hypervirulent strains.

[Assessment on ecological integrity of typical lakes, reservoirs and wetlands in Tianjin, China]

The ecological health assessment of lakes, reservoirs and wetlands can provide decision-making basis for ecosystem restoration and management. We selected 20 typical lakes, reservoirs and wetlands sampling points in Tianjin, based on physical, chemical, and biological community indicators data (zooplankton, phytoplankton, benthos, fish, large aquatic plants, riparian plants) obtained during the survey from August to September 2018. We constructed an index of ecological integrity (IEI) including physical integrity, chemical integrity, and biological integrity to evaluate their ecological health. The reference points were selected based on three aspects using standardized methods: habitat environmental quality index (QHEI), water quality status, and disturbance of human activities. The analytic hierarchy process was used to calculate the weight of the three indicators. The evaluation results of the ecological integrity of typical lakes, reservoirs and wetlands in Tianjin were finally obtained. The results showed that: 1) Among all the samples, "healthy" points accounted for 5.0%, "good" points accounted for 20.0%, "general" points accounted for 35.0%, "worse" points accounted for 30.0%, and "poor" points accounted for 10.0%. Ecological health status of typical lakes, reservoirs and wetlands in Tianjin was at a general level, with a trend that the west was better than the east with significant spatial differences. 2) Reference points were selected based on the combination of habitat score, water quality conditions, and human activity disturbance. Water quality indicators could reduce subjectivity when selecting reference points and promote the application of ecological integrity evaluation. 3) The applicability verification results showed that IEI could better characterize the health status of each point, and the discrimination efficiency was obvious, which was suitable for evaluating the ecological health of lakes, reservoirs and wetlands.

Transfer and transformation mechanisms of Fe bound-organic carbon in the aquitard of a lake-wetland system during reclamation

Organic carbon (OC) can help control greenhouse gas emissions by participating in biogeochemical reactions and preventing the migration of contaminants in groundwater systems. The association of OC with Fe (Iron) oxide minerals plays a significant role in stabilizing OC and regulating the biogeochemical cycles of OC on the earth's surface. Reclaiming farmland from lakes changes an original lake into a wetland, but the destiny of Fe bound-OC in the underlying aquitard during this process has been poorly understood. The mechanisms of migration and transformation of Fe bound-OC were investigated in subsurface aquitard sediments of three typical boreholes in the Chen Lake wetland, central China. The Fe bound-OC content in the natural sedimentary conditions (borehole A), transition area (borehole B), and intensive reclamation area (borehole C) were 0.17-3.87, 0.28-3.98 and 0.13-7.08 mg g^-1, respectively. The reclamation changed the redox, water, and infiltration conditions of the surface environment, resulting in a transformation of Fe oxides phases, and then cause the change of content and structure of Fe bound-OC. The fresh organic matter provided by undecomposed crops causes oxygen- and nitrogen-rich compounds to combine with Fe oxides extensively through adsorption, resulting in higher δ¹³C values of Fe bound-OC than non-Fe bound-OC. Fe bound-OC has strong resistance to biodegradation. The Fe bound-OC: total OC ratios generated by adsorption and coprecipitation on the surface layer (0 to -3.5 m) of borehole C was 10.37% and 18.86%, 6.92% and 12.46% higher than those of boreholes A and B, respectively. Coprecipitation has a stronger OC-binding ability and enriches more carboxylates and aromatics, while adsorption gradually assumed a dominant position in OC-Fe interaction in deep aquitard. The reduction dissolution of Fe oxide causes Fe bound-OC to transfer into pore water, leading to an increase of Fe ion and dissolved OC in deep strata.

Decrease of both river flow and quality aggravates water crisis in North China: a typical example of the upper Yongding River watershed

Due to unevenly distributed water resources, semi-arid regions are particularly prone to severe water shortage and quality degradation. In this study, based on long-term hydrological database (1935-2015), and the latest available water quality data sets (2011-2016), we analyzed the water crisis and its driving forces in the upper Yongding River watershed, a typical water shortage area in North China. The results showed that human induced excessive water consumption is responsible for the significantly decreased river flow over the past eight decades. Although the capacity of the watershed wastewater treatment has improved, current water quality does not meet the requirements of the national water management goals, because of the excessive nitrogen and COD_Cr (chemical oxygen demand), which mainly come from the wastewater and feedlots discharge. Due to the decreased river flow, current Yongding River is unable to dilute and assimilate pollutions. The analysis of river pollutant load illustrated that more than 60 % of the nitrogen in the river water system is diverted for reservoir storage, and more than 50 % of the COD_Cr and TP are diverted for irrigation, thereby, increasing the risk of reservoirs eutrophication and threatening food safety. Besides, the high Cl^- (388.2 ± 322.5 mg/L) and SO₄^2- (470.6 ± 357.7 mg/L) imply that the upper river water are not suitable for drinking and irrigation purposes, and a potential risk of salinization if the river flow continues to decrease. We conclude that water resources over extraction and quality degradation are the main driving factors of the Yongding River water crisis.

Evaluating water resource sustainability from the perspective of water resource carrying capacity, a case study of the Yongding River watershed in Beijing-Tianjin-Hebei region, China

China is facing great challenges to balance its natural water resource use and eco-environment protection, especially in the north semi-arid region with large water consumption due to the rapid economic growth. This highlights the urgency to use water resource carrying capacity (WRCC) as a measure to maintain the sustainable development of the human and natural water system. Here, we used a coupled model based on the system dynamics and cellular automaton models to assess the WRCC under the critical value of water resource withdrawal ratio (40%) and its sustainability in the Yongding River watershed in Beijing-Tianjin-Hebei region, where the water use highly depends on river flow and nonrenewable groundwater resources. The analytical results showed that the current regional WRCC is severely overloaded due to strong human activities. The predicted results based on four scenarios, i.e., existing development, water saving, industrial restructuring, and integrated development schemes, showed that although the improvement of water saving and water use efficiency has mitigated the regional water shortage, evidenced by the increased WRCC, the water shortage would continue due to the increased water demand. Under the integrated development scenario, it will need at least additional 7.1 × 10⁸ m³ water per year (Beijing: 2.5 × 10⁸ m³, Tianjin: 0.8 × 10⁸ m³, Hebei: 3.8 × 10⁸ m³) via the water transfer project to maintain the sustainability in the next decades. Our research provides recommendations for reasonable water utilization and supplementation under the severe water crisis.

Investigation of the microplastics profile in sludge from China's largest Water reclamation plant using a feasible isolation device

Sewage sludge, which is widely applied to land as a fertilizer, is a key source of microplastics in the environment. We sought to develop a feasible device for isolation of microplastic from sewage sludge for further understanding their fates in the environment. In the present study, an effective isolation device, consisting of a fritted glass funnel and a glass filtration apparatus, was constructed to extract microplastics from sludge with nearly 100% recovery efficiency. Then, a high abundance of microplastics was detected in sludge sampled from China's largest sewage treatment plant. Among the 25 types of microplastic polymers confirmed by Fourier transform infrared spectroscopy, poly(11-bromoundecyl acrylate) (PBA) and poly(11-bromoundecyl methacrylate) (PBMA) accounted for 23.63% of total microplastics detected. Rayon, polyethylene (PE), polyethylene terephthalate (PET), polypropylene (PP), and copolymers, such as PP/PE and poly(styrene:acrylonitrile:butadiene) (ABS), were also detected. The shapes of these microplastics consisted of pellets, fragments, films, and microfibers. Characterization of the isolated microplastics revealed that domestic applications and vehicle products were the major sources of microplastic in sewage treatment sludge. Some priority recommendations were issued based on these results. In conclusion, the present study demonstrate that the device is effective for the isolation of microplastics from sludge.

Polysaccharide-based recoverable double-network hydrogel with high strength and self-healing properties

Polysaccharide-based hydrogels (PSBHs) have received significant attention for numerous bio-applications due to their biocompatibility and non-immunogenic performance. However, the construction of PSBH with superior mechanical properties by a simple method is rarely adequately researched. This study focuses on the construction of a novel PSBH with superior mechanical and recoverable properties by integrating the synergistic and complementary interactions of covalent bond-associated oxidized sodium alginate (SA-CHO) gel and hydrogen bond-associated agarose (Aga) gel. With the synergy and complementarity of the SA-CHO and Aga networks, the hydrogel exhibited 17 and 15 times (20 and 9 times) greater compressive stress and modulus, respectively, compared with the SA-CHO gel (Aga gel). The hydrogel also displayed excellent fatigue resistance, recurrent shapeability, acid resistance and recovery ability, as well as self-healing ability. This study provides a unique perspective for enhancing the mechanical properties of PSBH through the synergy and complementarity of different kinds of polysaccharides without sacrificing the functionality of the PSBH.

Phthalate Esters and Their Potential Risk in PET Bottled Water Stored under Common Conditions

A great deal of attention has been paid lately to release of phthalate esters (PAEs) from polyethylene terephthalate (PET) bottles into PET bottled drinking water due to their potential endocrine-disrupting effects. Three kinds of PAEs, including diethyl phthalate (DEP), dimethyl phthalate (DMP) and dibutyl phthalate (DBP), were detected in 10 popular brands of PET bottles in Beijing, ranging from 101.97 μg/kg to 709.87 μg/kg. Meanwhile, six kinds of PAEs, including DEP, DMP, DBP, n-butyl benzyl phthalate (BBP), di-n-octyl phthalate (DOP) and di(2-ethylhexyl) phthalate (DEHP), were detected in PET bottled water, ranging from 0.19 μg/L to 0.98 μg/L, under an outdoor storage condition, while their concentrations ranged from 0.18 μg/L to 0.71 μg/L under an indoor storage condition. Furthermore, the concentrations of PAEs in brand D and E bottles were slightly increased when the storage time was prolonged. In addition, the concentrations of PAEs in commercial water contained in brand B and H bottles and pure water contained in brand E and G bottles were also slightly increased with the increase of storage temperature. Interestingly, DBP mainly contributed to the increased PAEs levels in simulation water. These results suggest that a part of the PAEs in PET bottled water originated from plastic bottles, which was related to the storage time and temperature. However, the PAEs in PET bottled water only pose a negligible risk to consumers if they follow the recommendations, such as storage at a common place (24 °C), away from sun and in a short period of time.

Humidity and Heat Dual Response Cellulose Nanocrystals/Poly(N-Isopropylacrylamide) Composite Films with Cyclic Performance

It has been widely reported that cellulose nanocrystals (CNCs) demonstrate a special structural color, which stems from chiral nematic domains. Herein, the humidity and heat dual response nanocomposite films with multilayered helical structure were prepared by self-assembling of CNCs and hydrazone groups modified poly(N-isopropylacrylamide) (PNIPAM) copolymers. Furthermore, glutaraldehyde was involved to act as a chemical linker to improve cyclic stability by forming acylhydrazone bonds. The structural color of the films could be easily regulated by humidity, heat, or the content of modified PNIPAM copolymers. The absorption of water in higher humidity led to volume expansion of the resin, resulting in a red shift for up to 145 nm. In contrast, the resin shrank under the temperature above the lower critical solution temperature of PNIPAM, leading to a blue shift for up to 87 nm. It was notable that the change of color can be easily captured by the naked eyes. Moreover, the films exhibited excellent stability and cyclicity in response to either vapor or liquid water due to the chemical linking between CNCs and resins. The as-prepared CNCs/PNIPAM nanocomposite films with humidity or heat responsibilities are promising in stimuli-responsive sensors, printing industry, surface decorations, and so forth.

Microfiber release from different fabrics during washing

Microfiber is a subgroup of microplastics and accounts for a large proportion of microplastics in aquatic environment, especially in municipal effluents. The purpose of the present study was to quantify microfiber shedding from three most populate synthetic textile fabrics: polyester, polyamide, and acetate fabrics. The results showed that more microfibers were released after washing with a pulsator laundry machine than a platen laundry machine. The greatest number of microfibers was released from acetate fabric, which was up to 74,816 ± 10,656 microfibers/m² per wash, although microfibers were shed from all materials. Moreover, an increasing trend was found in the number of microfibers shedding from synthetic fabrics with the washing temperature increasing, and greater microfiber release occurred when washing fabrics with detergent rather than with water alone. The lint filter bag equipped with the pulsator laundry machine retained the longer microfibers (>1000 μm), but not the shorter microfibers (<500 μm) instead of releasing into the drainage system. Our data suggested that microfibers released during washing of synthetic fabrics may be an important source of microfibers in aquatic environment due to the increasing production and use of synthetic fabrics globally. Thus, more efficient filtering bags or other technologies in household washing machines should be developed to prevent and reduce the release of microfibers from domestic washing.

Interlock or Chemical Bond: Investigation on the Interface of Graphene Oxide and Styrenic Block Copolymers as Layer-by-Layer Films

In the paper, graphene oxide (GO) and two kinds of styrenic resins, poly[styrene-b-(ethylene-co-butylene)-b-styrene] (SEBS) and maleic anhydride (MA) grafted SEBS (MA-g-SEBS), were utilized to explore the interfacial interaction of carbon-based materials and block copolymers as layer-by-layer (LBL) assembly films. The details of the interlayer interaction of the two kinds of composite films were investigated through the analysis of the mechanical properties and internal structure of the composites. For the SEBS/GO composite film, the "interlock" structure tended to form between the GO sheets and SEBS resin, and the physical "interlocking effect" could make full use of the excellent mechanical properties of GO nanosheets. As a result, both failure strength and elongation at break of the SEBS/GO composite film were enhanced by 50 and 25%, respectively. On the other hand, some different structures were found in the MA-g-SEBS/GO composite film, where the GO sheets stacked onto the resin closely because of the chemical interaction between them and no obvious "interlocks" was found within the interface, and the chemical interface interaction was strong enough to prevent the slide of GO nanosheets under tension after the graphene sheets were highly oxidized, so the mechanical properties of the MA-g-SEBS/GO composite film could be also enhanced. Based on an overall consideration of the research results of these LBL assembled composites, choosing more perfect materials and structures is needed, which should use physical and chemical interfacial interactions more efficiently, to obtain better mechanical properties of inorganic carbon-organic resin composites.

Removal of microplastics in municipal sewage from China's largest water reclamation plant

Municipal sewage treatment plants (STPs) are an important point source of microplastics in domestic waterways. In the present study, effluents from the largest water reclamation plant in China were sampled throughout the treatment process and microplastics were extracted and identified to evaluate their removal. As expected, microplastics were detected in the influent (12.03 ± 1.29 items/L). Following treatment, concentrations of microplastics were reduced by greater than 95% and 0.59 ± 0.22 items/L of microplastics were detected in reclaimed waters. Among detected microplastics, 18 types of polymers of ten colors were identified. Polyethylene terephthalate (PET), polystyrene (PS) and polypropylene (PP) accounted for greater than 70% of detected microplastics. Furthermore, microfibers were the dominant shape detected with an average size of 1110.72 ± 862.95 μm. However, microparticles accounted for only 14.08% of total microplastics with an average size of 681.46 ± 528.73 μm. Results of the present study suggest that current treatment technologies employed at the chosen STP are efficient to remove the majority of microplastics, however consideration of STPs as a point source of microplastics is important due to the large volumes of effluents being released into the aquatic environment on a consistent basis.

Assessment of the water resource carrying capacity based on the ecological footprint: a case study in Zhangjiakou City, North China

With the rapid economic development in the past decades, industrialization and urbanization in China has also rapidly developed and will continue in the next decades. However, the regional water shortage has posed great challenges for the sustainable development of big cities especially in north China. Here, we used the water ecological footprint model combined with the system dynamic model to assess the water resource carrying capacity and its sustainability in Zhangjiakou City, a typical water shortage city in north China. The calculated results showed that irrigation was the largest water consumer in Zhangjiakou. There existed a clear gap between water supply and water consumption in this city and such a gap is demonstrated by the high water resource pressure index. Our predicted results based on the water resource ecological footprint and the system dynamic model showed that although the improving water use efficiency has relieved the regional water shortage pressure, the efficiency gained would be to a large degree offset by increased water demands due to the increasing economic development. The annual average water shortage in Zhangjiakou in 2007-2050 would be up to 8.53 × 10⁸ m³, nearly half of the total local average annual water resource. To deal with the severe water shortage over the next three decades, great attention should be paid to scientific water resource managements and water pollution control. This research provides a long-term view of water resource pressure and provides recommendations for a sustainable water use under the rapid regional socioeconomic development.

Freshwater snail Parafossarulus striatulus estrogen receptor: Characteristics and expression profiles under lab and field exposure

The modes of action by which putative endocrine disrupting chemicals (EDCs) elicit toxicity in mollusks remains unclear due to our limited understanding of the molluscan endocrine system. We identified and partially characterised the estrogen receptor (ER) of the mollusk Parafossarulus striatulus. The full-length cDNA of the ER of P. striatulus (psER) was isolated and found to have an ORF of 1386 bp which corresponded to 461 amino acids. Phylogenetic analysis revealed that psER is an orthologue of ER of other mollusks. Moreover, the DNA-binding domain, ligand-binding domain, P-box, D-box, and AF2 domain were also identified in psER. Exposure of females and males to 17β-estradiol (E2, 100 ng/L) for 24 h and 72 h did not alter psER transcription, but exposure to 17α-methyltestosterone (MT, 100 μg/L) for 72 h significantly decreased ER transcription in females only (p < 0.05). psER transcription was surveyed in males and females seeded in different regions in Taihu Lake, China. psER transcription were elevated among females and males maintained at site ML. This elevation was statistically significant (p < 0.05) among male snails as compared to snails held at the more pristine site of SZ. This was different to the results from lab, implying that some unknown chemicals or other environmental factors in field could affect psER transcription level in snails. Furthermore, females and males held at site ML also exhibited a significant elevation in vitellogenin transcription as compared to snails held at site SZ, suggesting that vitellogenin production may be directly regulated by psER or co-regulated with psER in this species.

[Concentration, Flux, and Emission Factor of N2O in Rivers with Different Nitrogen Pollution Features]

In this study, 22 rivers in Tieling City were selected to study the concentration, flux, and emission factor (EF_5r) of N₂O. Based on the concentrations and components of nitrogen (N), the 22 rivers can be divided into ammonia nitrogen (NH₄⁺)-polluted rivers (mean NH₄⁺=5.86 mg·L^-1), nitrate nitrogen (NO₃^-)-polluted rivers (mean NO₃^-=3.05 mg·L^-1), and N-limited rivers[mean DIN (NH₄⁺+ NO₃^-)=1.04 mg·L^-1]. Overall, the concentration of N₂O ranges from 17.03 to 9028.60 nmol·L^-1, with a mean value of 546.75 nmol·L^-1 (mean saturation=6256%). The emission fluxes across the water-air interface range from 17.21 to 15655.3 μg·(m²·h)^-1, with a mean value of 949.36 μg·(m²·h)^-1, indicating that those rivers are net sources of atmospheric N₂O. The concentration and flux of N₂O observed in NH₄⁺-polluted rivers are significantly higher than that in the NO₃^--polluted and N-limited rivers. According to the method proposed by the IPCC, EF_5r varies greatly among the three types of rivers and the coefficient of variation of EF_5r is 445%. The EF_5r for NO₃^--polluted rivers is on average 0.0005, which is lower than the recommended value of 0.0025. However, the EF_5r for NH₄⁺-polluted rivers is on average 0.4456, which is 180 times the recommended value and may be caused by the lower NO₃^- concentration of those rivers. The EF_5r of N-limited rivers averages 0.0050 and is two times the recommended value. Thus, it is necessary to assess the pollution status of N before calculating the EF_5r for the riverine system. We suggest that the EF_5r for NH₄⁺-polluted and N-limited rivers should be calculated using[N₂O]/[NH₄⁺] and[N₂O]/[DIN], respectively, without assessing the composition and concentration of N.

Effects of land use on the concentration and emission of nitrous oxide in nitrogen-enriched rivers

Nitrous oxide (N₂O) is a potent greenhouse gas that contributes to climate change and stratospheric ozone destruction. Nitrogen-enriched rivers are significant sources of atmospheric N₂O. This study conducted a one-year field campaign in seven N-enriched rivers draining urban, rural, and agricultural land to determine the link between the production, concentrations, and emissions of N₂O and land use. Estimated N₂O fluxes varied between 1.30 and 1164.38 μg N₂O-N m^-2 h^-1 with a mean value of 154.90 μg N₂O-N m^-2 h^-1, indicating that rivers were the net sources of atmospheric N₂O. Concentrations of N₂O ranged between 0.23 and 29.21 μg N₂O-N L^-1 with an overall mean value of 3.81 μg N₂O-N L^-1. Concentrations of ammonium and nitrate in urban and rural rivers were high in the cold season. The concentrations were also high in agricultural rivers in the wet season. N₂O concentrations and emissions in rural and urban rivers followed a similar pattern to ammonium and a similar pattern to nitrate in agricultural rivers. A strong link between the concentrations and emissions of N₂O and land use was observed. N₂O concentrations in and emissions from the rivers draining the urban and rural areas were significantly higher than the rivers draining the agricultural areas (P < 0.01). Stepwise regression analysis indicated that dissolved N₂O were primarily influenced by NH₄⁺ in agricultural rivers and by NO₃^- in rural rivers; while dissolved N₂O in urban rivers was primarily predicted by temperature and reflected the integrated impact of sewage input and river hydrology. Nitrate-N and NO^3--O isotope data and linear regression of N₂O and river water variables strongly indicated that dissolved N₂O was mainly derived from nitrification in agricultural rivers and denitrification in rural and urban rivers.

No impacts of microcystins on wild freshwater snail Bellamya Aeruginosa fecundity from a eutrophic lake

The preliminary investigation at shoreline along Taihu lake with different degrees of eutrophication status found no significant relationship between the microcystin-LR concentrations and the freshwater snail Bellamya aeruginosa fecundity or the abundance of wild freshwater snails. To further confirm the impact of eutrophication on the reproductive ability of snails, ecological mesocosm experiments were employed at four sites in Taihu lake during the algal blooming period, and no significant relationship was also found between MC-LR concentrations and snail fecundity. These results implied that eutrophication does not negatively or positive affect snail fecundity in Taihu Lake, a typical eutrophication lake in China.

Transcriptomic responses of the freshwater snail (Parafossarulus striatulus) following dietary exposure to cyanobacteria

Freshwater snails are promising bioindicators that can be used in ecotoxicological testing and ecological risk assessments. To screen molecular responses following mollusk exposure to algal blooms, whole transcriptome sequencing was performed with the freshwater snail (Parafossarulus striatulus) fed with blue algae (Microcystis aeruginosa). A total of 86,848 unigenes were assembled, and 10,413 unigenes were annotated in the TrEMBL, Pfam, KEGG, and SwissProt databases. In snails fed with both green and blue algae, a total of 276 differentially expressed unigenes were identified, though there were limited differences in snails fed with only green algae. In addition, ten randomly selected differentially expressed unigenes were analyzed in snails collected from Taihu Lake, China. The expression of four unigenes exhibited a trend consistent with that observed in transcriptome profiling of laboratory snails. The results of this study provide an invaluable resource for enhancing our understanding of ecotoxicology following the occurrence of algal blooms in lakes.

[Spatio-temporal Distribution and Source Apportionment of Nitrogen in Rivers of Tieling]

This study analyzed the spatio-temporal distribution and sources of nitrogen (N) in 22 rivers in Tieling City during 2013-07-2014-07. The results showed that the concentrations of TN, NO₃^--N, and NH₄⁺-N were 1.26-18.85, 0.53-11.8, and 0.3-15.7 mg·L^-1, with an annual mean value of (5.8±1.9), (2.8±1.74), and (2.0±1.1) mg·L^-1, respectively. Overall, NO₃^--N was the main form of N with a percentage of 48%. The concentration of N in the wet season was significantly higher than that in the normal and dry seasons. According to the standards for surface water quality, water quality in eight rivers was worse than grade Ⅲ. Tiaozi River and Xiaoqing River were seriously polluted by ammonia N with a grade Ⅴ water quality through the sampling period, while Xiliao River, Xiaohezi River, and Liao River met the water quality standards. During the sampling period, δ¹⁵ N and δ¹⁸ O in nitrate in river waters were -3.0‰-23.9‰ and -11.7‰-57‰, respectively. Based on the data on the isotopes of N and O, N in the rivers in Tieling City mainly originated from human and animal excreta, industrial effluents, and domestic sewage. Sources of riverine N varied with seasons. For example, N in Tiaozi River and Nianpan River was mainly from fertilizer use and soil nitrogen in the wet season while it was from the industrial effluents and domestic sewage in the dry season.

Visual field impairment predicts recurrent stroke after acute posterior circulation stroke and transient ischemic attack

AIMS

To evaluate whether visual field impairment (VFI) can predict stroke recurrence in patients with vertebral-basilar (VB) stroke.

METHODS

A total of 326 patients were eligible for a VFI evaluation within 1 week of stroke onset. One-year follow-up data were obtained after VB stroke and other vascular events. All predictors were determined using Cox regression models.

RESULTS

The overall incidence of recurrent VB stroke and transient ischemic attack (TIA) was 29% (n = 92). After multivariate adjustment, severe and moderate VFI were predictors of recurrent VB stroke and TIA.

CONCLUSIONS

VFI is an independent predictor of recurrent VB stroke and TIA.

Effects of storage temperature and time of antimony release from PET bottles into drinking water in China

Antimony (Sb) concentrations were measured in 10 brands of PET bottled drinking water available in supermarkets in China. To simulate general storage habits based on market research, these PET bottles with drinking water were stored for 4 weeks in a lab or a car trunk during the summer. Although the PET package material of brand A had the lowest Sb level (142.71 ± 29.81 μg/g), it showed a significant increase in Sb concentrations when stored in both the car trunk and the lab. There was significant release of Sb from the PET bottles into the water following 24 h of incubation at ≥ 40 °C (40, 50, 60, and 70 °C), especially at 70 °C. The potential health risk of Sb release from PET bottles was calculated based on daily intake values and determined to be acceptable for consumers under normal storage conditions.