The four copper nanoparticles (CuNPs) with the size of 25, 50, 78 and 100 nm and one type of micron-sized particles (MPs) (~500 nm) were exposed to two mammalian (H4IIE and HepG2) and two piscine (PLHC-1 and RTH-149) cell lines to test the species-specific toxicities of CuNPs. The results showed that the morphologies, ion release and size of the particles all played an important role when investigating the toxicity. Furthermore, the authors found that the particle forms of CuNPs in suspensions highly contribute to the toxicity in all exposed cell lines whereas copper ions (Cu(2+)) only caused significant responses in mammalian cell lines, indicating the species-specific toxicity of CuNPs. This study revealed that the morphologies, ion release rate of NPs as well as the species-specific vulnerabilities of cells should all be considered when explaining and extrapolating toxicity test results among particles and among species.

Titanium dioxide nanoparticles (nano‐TiO2) are widely used in consumer products, raising environmental and health concerns. An overview of the toxic effects of nano‐TiO2 on human and environmental health is provided. A meta‐analysis is conducted to analyze the toxicity of nano‐TiO2 to the liver, circulatory system, and DNA in humans. To assess the environmental impacts of nano‐TiO2, aquatic environments that receive high nano‐TiO2 inputs are focused on, and the toxicity of nano‐TiO2 to aquatic organisms is discussed with regard to the present and predicted environmental concentrations. Genotoxicity, damage to membranes, inflammation and oxidative stress emerge as the main mechanisms of nano‐TiO2 toxicity. Furthermore, nano‐TiO2 can bind with free radicals and signal molecules, and interfere with the biochemical reactions on plasmalemma. At the higher organizational level, nano‐TiO2 toxicity is manifested as the negative effects on fitness‐related organismal traits including feeding, reproduction and immunity in aquatic organisms. Bibliometric analysis reveals two major research hot spots including the molecular mechanisms of toxicity of nano‐TiO2 and the combined effects of nano‐TiO2 and other environmental factors such as light and pH. The possible measures to reduce the harmful effects of nano‐TiO2 on humans and non‐target organisms has emerged as an underexplored topic requiring further investigation.

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Our aim of this article is to reconstruct a signal from undersampled data in the situation that the signal is sparse in terms of a tight frame. We present a condition, which is independent of the coherence of the tight frame, to guarantee accurate recovery of signals which are sparse in the tight frame, from undersampled data with minimal l 1 -norm of transform coefficients. This improves the result in [1]. Also, the l q -minimization (0 < q < 1) approaches are introduced. We show that under a suitable condition, there exists a value q 0 ∈ (0, 1] such that for any q ∈ (0, q 0 ), each solution of the l q -minimization is approximately well to the true signal. In particular, when the tight frame is an identity matrix or an orthonormal basis, all results obtained in this paper appeared in [13] and [26].

Copper nanoparticles (CuNPs) are used extensively in a wide range of products and the potential for toxicological impacts in the aquatic environment is of high concern. In this study, the fate and the acute toxicity of spherical 50nm copper nanoparticles was assessed in juvenile rainbow trout (Oncorhynchus mykiss), fathead minnow (Pimephales promelas) and zebrafish (Danio rerio) for in vivo aqueous exposures following standardized OECD 203 guideline tests. The fate of the CuNPs in the aqueous media was temperature dependent. At the higher study temperature (26±1°C), there was both an enhanced particle aggregation and higher rate of dissolution compared with that at the lower study temperature (15±1°C). 96h LC50s of the CuNPs were 0.68±0.15, 0.28±0.04 and 0.22±0.08mg Cu/L for rainbow trout, fathead minnow and zebrafish, respectively. The 96h lowest-observed-effect concentration (LOEC) for the CuNPs were 0.17, 0.023 and <0.023mg/L for rainbow trout, fathead minnow, and zebrafish respectively, and are below the predicted environmental concentration of CuNPs for some aquatic environments suggesting a possible ecotoxicological risk to fish. Soluble copper was one of main drivers for the acute toxicity of the copper nanoparticles suspensions. Both CuNPs suspension and copper nitrate caused damage to gill filaments and gill pavement cells, with differences in sensitivity for these effects between the fish species studied. We show therefore common toxicological effects of CuNPs in different fish species but with differences in sensitivity with implications for hazard extrapolation between fish species.

The development of market integration has an important effect on regional green total factor productivity (GTFP). Based on the panel data of 30 provinces in China from 2008 to 2017, this paper studies the spatial effect and transmission mechanism of market integration on regional green total factor productivity by calculating the Malmquist–Luenburger index and using spatial econometric models. It was found that market integration can promote the improvement of regional green total factor productivity. This positive effect is not only directly reflected in the region, it also indirectly promotes the growth of GTFP in nearby regions. In addition, market integration has shown significant positive effects on efficiency improvement and technological progress, and market integration has affected regional green total factor productivity through them. The above conclusions are of great significance for China to develop a green economy and promote high-quality economic transformation.

Summary Carbon neutrality by 2060 is the recent expression of China's international commitment to reduce its carbon dioxide emissions. Energy and chemical sectors, the two main contributors for carbon dioxide emissions in China, are the biggest bottlenecks for reaching the objective of carbon neutrality. Moreover, coal-to-ammonia production and coal-to-methanol production are the major CO 2 emission process contributors in China's coal chemical sector. Herein, a possible route to the carbon neutral target based on energy-chemical nexus for electricity generation as well as methanol and ammonia production is proposed in this study. The most cost-effective solution for meeting the commitment is identified by considering regional variations in renewable and non-renewable resources and adopting an optimized regional cooperation. According to the roadmap presented in this study, an optimized combination of fossil fuels and renewable energies forming “blue energy economy” is feasible and promising.