Water pollution caused by organic wastewater has become a serious concern worldwide. Fenton oxidation process is one of the most effective and suitable methods for the abatement of organic ...pollutants. However, the process has three obvious shortcomings: the narrow working pH range, the high costs and risks associated with handling, transportation and storage of reagents (H2O2 and catalyst), the significant iron sludge related second pollution. In order to overcome these shortcomings, various optimized Fenton processes have been widely studied. Therefore, a summary of the study status of Fenton optimization processes is necessary to develop a novel and high efficiency organic wastewater treatment method. Based on the optimization perspective, taking shortcomings of Fenton process as a breakthrough, the fundamentals, advantages and disadvantages of single Fenton optimization processes (heterogeneous Fenton, photo-Fenton and electro-Fenton) for organic wastewater treatment were reviewed and the corresponding reaction mechanism diagrams were drawn in this paper. Then, the feasibility and application of the coupled Fenton optimization processes (photoelectro-Fenton, heterogeneous electro-Fenton, heterogeneous photoelectro-Fenton, three-dimensional electro-Fenton) for organic wastewater treatment were discussed in depth. Additionally, the effect of some important operation parameters (pH and catalyst, H2O2, organic pollutants concentration) on the degradation efficiency of organic pollutants was studied to provide guidance for the optimization of operation parameters. Finally, the possible future research directions for optimized Fenton processes were given. The review aims to assist researchers and engineers to gain fundamental understandings and critical view of Fenton process and its optimization processes, and hopefully with the knowledge it could bring new opportunities for the optimization and future development of Fenton process.
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•Review of single Fenton optimization processes for organic wastewater treatment.•Review of coupled Fenton optimization processes for organic wastewater treatment.•Key operational parameters are discussed.•Insights into future research directions for optimized Fenton processes.
A novel severe acute respiratory syndrome human coronavirus (SARS HCoV) was identified from respiratory illness patients (named SARS-CoV-2 by ICTV) in December 2019 and has recently emerged as a ...serious threat to world public health. However, no approved drugs have been found to effectively inhibit the virus. Since it has been reported that HIV protease inhibitors can be used as anti-SARS drugs by targeting SARS-CoV-1 3CLpro, we chose six approved anti-HIV drugs and investigated their binding interactions with 3CLpro to evaluate their potential to become clinical drugs for the new coronavirus pneumonia (COVID-19) caused by SARS-CoV-2 infection. The molecular docking results indicate that the 3CLpro of SARS-CoV-2 has a higher binding affinity for all the studied inhibitors than does SARS-CoV-1. Two docking complexes (indinavir and darunavir) with high docking scores were further subjected to MM-PBSA binding free energy calculations to detail the molecular interactions between these two protease inhibitors and SARS HCoV 3CLpro. Our results show that, among the inhibitors tested, darunavir has the highest binding affinity with SARS-CoV-2 and SARS-CoV-1 3CLpro, indicating that it may have the potential to be used as an anti-COVID-19 clinical drug. The mechanism behind the increased binding affinity of HIV protease inhibitors toward SARS-CoV-2 3CLpro (as compared to SARS-CoV-1) was investigated by MD simulations. Our study provides insight into the possible role of structural flexibility during interactions between SARS HCoV 3CLpro and inhibitors and sheds light on structure-based design of anti-COVID-19 drugs targeting SARS-CoV-2 3CLpro.
A novel severe acute respiratory syndrome human coronavirus (SARS HCoV) was identified from respiratory illness patients (named SARS-CoV-2 by ICTV) in December 2019 and has recently emerged as a serious threat to world public health.
The reaction of 2,5-dihydro-1H-phosphole 1-oxide 1 with ArB(pin) 3 in the presence of a chiral (R)-segphos–rhodium catalyst under highly basic conditions (10 equiv of KOH) gave high yields of ...(1S,3S)-3-arylphospholane 1-oxide 4 with high diastereoselectivity as well as high enantioselectivity. Equilibration of 1 with its 2,3-dihydro isomer 2, which is chiral and racemic, by base-catalyzed olefin isomerization followed by kinetic resolution of 2 with the chiral rhodium catalyst realized the present dynamic kinetic resolution.
In this paper, the discrete wavelet transform (DWT) and a chaotic system were combined with a convolutional neural network (CNN) and applied to the diagnosis of insulation faults in XLPE ...(cross-linked polyacetylene) power cables. First, four different types of insulation faults in power cables were constructed, including the normal state of the cable, the short outer semi-conducting layer, impurities in the insulation layer, and insulation layer damage, and a high-speed capture card (NI PXI-5105) was adopted to measure the partial discharge (PD) signal, which was then filtered through discrete wavelet transform. Then, based on the Lorenz chaotic system, a dynamic error scatter diagram was established as the feature of each fault state. Finally, the dynamic error scatter diagram was processed by CNN to recognize four different types of faults in the power cable. The test results show that the method proposed in this paper can quickly recognize the fault state of power cables and has excellent performance in terms of recognition accuracy, which reaches 97.5%. Therefore, the proposed method can effectively detect the fault signal changes of power cables and identify the fault state of power cables in real time.
•Magnesium nitrate hydrate pyrolysis took place via three contributing processes.•Three processes were successfully separated by deconvolution.•Contributions of three processes were 39.9 ± 0.2 %, ...13.6 ± 0.2 % and 46.5 ± 0.2 %.•Kinetic triplets of separated processes were determined by kinetic analysis.•Three processes obeyed diffusion, order-based and nucleation and growth mechanisms.
The multistep thermal decomposition behavior and kinetic feature of magnesium nitrate hydrate (MNH) were studied systematically in this study. Firstly, the multistep reaction processes in MNH pyrolysis were identified by Thermogravimetry-Fourier Transform Infrared analysis. Then, a common method of data processing, mathematical peak deconvolution, was used to separate such complex multistep reaction processes. Additionally, kinetic triplets of each separated process were determined by Friedman isoconversional method and Ozawa kinetic equation. Finally, kinetic features of each separated process were interpreted in terms of the physico-geometrical reaction mechanism. The results showed that MNH pyrolysis was a complex multistep reaction, including three reaction processes. The first two reaction processes were characterized by evolution of H2O, whereas the third reaction process was characterized by evolution of NO2. Three processes obeyed diffusion, order-based and nucleation and growth mechanisms, with E(apparent activation energy) = 80 ± 1, 137 ± 2, 227 ± 4 kJ/mol and A(pre-exponential factor)=(2.5 ± 0.2)×109, (1.5 ± 0.1)×1011 and (8.8 ± 0.2)×1015 s−1, respectively.
Metastasis is the primary cause of cancer-related death all over the world. Metastasis is a process by which cancer spreads from the place at which it first arose to distant locations in the body. It ...is well known that several steps are necessary for this process, including cancer cell
epithelial-mesenchymal transition (EMT), cell migration, resistance to anoikis, and angiogenesis. Therefore, investigating the molecular mechanism of regulating cancer metastasis progress may provide helpful insights in the development of efficient diagnosis and therapeutic strategy.
Recent studies have indicated that long noncoding RNAs (lncRNAs) play important roles in cancer metastasis. lncRNAs are the nonprotein coding RNAs that have a size longer than 200 nucleotides. More and more studies have indicated that lncRNAs are involved in a broad range of biological processes
and are associated with many diseases, such as cancer. The role of lncRNAs in cancer metastasis has been widely studied; however, lncRNAs are mainly involved in the EMT process on the current literature. This review focuses on the mechanisms underlying the role of lncRNAs in cancer metastasis.
The concentrations, bioavailability, distribution, and sources of heavy metals in soils of a typical region from coal industrial city of Tangshan, North China, were investigated. A total of 240 ...surface (0–20 cm) and sub-surface (20-40 cm) soil samples were collected and analyzed for the heavy metals of mercury (Hg), lead (Pb), cadmium (Cd), zinc (Zn), copper (Cu), chromium (Cr), arsenic (As), and nickel (Ni). The concentrations of these metals were lower than the national guideline values. However, accumulation of Zn, Pb, Cd, Hg, and Cu in the surface soils, and Zn, Cu, Cd, and Hg in the sub-surface soils was observed compared with their background values. The pollution indices of geo-accumulation (Igeo) and contamination factor (CF) showed that most soil samples were slightly to moderately polluted by Hg and Cd. Cd and Hg had the higher percentages (1.16–46.8%) in the water-soluble and exchangeable fractions and were considered potentially bioavailable and risky to the ecosystem. A combination of spatial analysis, principal component analysis (PCA), and positive matrix factorization (PMF) model was used to assess the sources of heavy metals. Anthropogenic sources contributed to 80.2% of the heavy metal concentrations in soils, indicating the great influence on soil heavy metal accumulation. Coal-related industrial activities, sewage irrigation and the application of agrochemicals, and vehicle emission were the possible anthropogenic sources of heavy metals.
•Heavy metals accumulate in the surface and sub-surface soils at different levels•Hg and Cd show high pollution level and bioavailability and pose more risk.•Anthropogenic activities contribute greatly to heavy metal accumulation in soils.•Coal industries, agricultural activity, and vehicle emission are the main inputs.
Abstract
In order to realize the large-scale and factory production and transportation of stairs in prefabricated buildings, this paper proposes a prefabricated stair mold, and uses midas Gen to ...conduct finite element analysis on the stair mold, and obtains the force size of concrete in the form of fluid on the stair mold after pouring. Thus, the displacement contour, stress and local and global deformation rules of each plate of the stair mold are obtained.
In remote sensing scene classification (RSSC), features can be extracted with different spatial frequencies where high-frequency features usually represent detailed information and low-frequency ...features usually represent global structures. However, it is challenging to extract meaningful semantic information for RSSC tasks by just utilizing high- or low-frequency features. The spatial composition of remote sensing images (RSIs) is more complex than that of natural images, and the scales of objects vary significantly. In this article, a multiscale feature fusion covariance network (MF 2 CNet) with octave convolution (Oct Conv) is proposed, which can extract multifrequency and multiscale features from RSIs. First, the multifrequency feature extraction (MFE) module is used to obtain fine-grained frequency features by Oct Conv. Then, the features of different layers in MF 2 CNet are fused by the multiscale feature fusion (MF 2 ) module. Finally, instead of using global average pooling (GAP), global covariance pooling (GCP) extracts high-order information from RSIs to capture richer statistics of deep features. In the proposed MF 2 CNet, the obtained multifrequency and multiscale features can effectively improve the performance of CNNs. Experimental results on four public RSI datasets show that MF 2 CNet has advantages in RSSC over current state-of-the-art methods. The source codes of this method can be found at https://github.com/liuqingxin-chd/MF2CNet .
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