Effects of chemical additives and mature compost on reducing nitrogen loss during food waste composting.

This study is aimed at adding different types of mature compost and sulfur powder, as additives into food waste composting to investigate the effect on nitrogen loss and compost maturity. The composting experiment used the in-vessel composting method and was conducted continuously for 15 days. High-throughput sequencing was used to analyze the bacterial community during composting. Results showed that the secondary fermentation mature compost mixed with sulfur powder group had the most reduction of ammonia emission (56%) and the primary fermentation mature compost amendments were the most effective for nitrous oxide emission reduction (37%). The temperature, pH, and nitrogen forms of transformation of the pile significantly affect the nitrogen loss during composting. Firmicutes helped to promote the rapid warming of the pile, and Actinobacteria and Proteobacteria played an important role in decomposition of organic matter. Thermobifida and Ureibacillus had a main contribution to the rapid degradation of organic matter in the process of composting. The relative abundance of nitrogen-fixing bacteria was higher, and the relative abundance of predominantly ammonifying and denitrifying bacteria was lower than the control group, with the addition of different additives.

Investigation of CuCoFe-LDH as an efficient and stable catalyst for the degradation of acetaminophen in heterogeneous electro-Fenton system: Key operating parameters, mechanisms and pathways.

Pharmaceuticals, as anthropogenic pollutants in a wide range of water sources, generally require specific treatment methods for degradation. A trimetallic layered double hydroxide (CuCoFe-LDH) was successfully fabricated by coprecipitation and applied as a novel heterogeneous electro-Fenton (EF) catalyst for the degradation of acetaminophen (ACT) from aqueous environments. The EF experiments showed that the CuCoFe-LDH/EF process achieved 100% of ACT degradation efficiency within 60 min at pH = 5, catalyst dosage of 0.50 g/L, current density of 10 mA/cm2 and initial ACT concentration of 20 mg/L. An impressive (>80%) mineralization of ACT was obtained over a wide pH range (pH 3-9) after 180 min. Meanwhile, the role of ·OH and O2.- were certified by radical quenching experiments and electron paramagnetic resonance (EPR) analysis. Through mechanism exploration, the coexistence of Cu and Co on Fe-based LDHs can accelerate the interfacial electron transfer and promote the formation of the reactive oxygen species (ROS), thus facilitating the EF process. Furthermore, the degradation by-products and possible degradation pathways of ACT in the CuCoFe-LDH/EF process were proposed. The reusability test and the treatment of various typical organic pollutants experiments indicated that the CuCoFe-LDH/EF process has excellent stability and broad application prospects. This work provides a valuable reference for the treatment of pharmaceuticals by the heterogeneous EF process in a wide range of pH.

Selective editing of a peptide skeleton via C-N bond formation at N-terminal aliphatic side chains.

The applications of peptides and peptidomimetics have been demonstrated in the fields of therapeutics, diagnostics, and chemical biology. Strategies for the direct late-stage modification of peptides and peptidomimetics are highly desirable in modern drug discovery. Transition-metal-catalyzed C-H functionalization is emerging as a powerful strategy for late-stage peptide modification that is able to construct functional groups or increase skeletal diversity. However, the installation of directing groups is necessary to control the site selectivity. In this work, we describe a transition metal-free strategy for late-stage peptide modification. In this strategy, a linear aliphatic side chain at the peptide N-terminus is cyclized to deliver a proline skeleton via site-selective δ-C(sp3)-H functionalization under visible light. Natural and unnatural amino acids are demonstrated as suitable substrates with the transformations proceeding with excellent regio- and stereo-selectivity.

N-doped carbon intercalated Fe-doped MoS2 nanosheets with widened interlayer spacing: An efficient peroxymonosulfate activator for high-salinity organic wastewater treatment.

Peroxymonosulfate (PMS) heterogeneous catalysis dominated by nonradical pathway showed excellent adaptability for pollutant removal in complex water matrixes. Herein, ultra-small Fe-doped MoS2 nanosheets with N-doped carbon intercalation (CF-MoS2) were synthesized via a one-step hydrothermal method to treat high salinity organic wastewater. CF-MoS2 exhibited an expanded interlayer spacing by 1.63 times and the specific surface area by 9 times compared with Fe-doped MoS2 (F-MoS2), substantially increasing the active sites. Homogeneous Fe2+ catalytic experiments confirmed that the promotion of carbon intercalated MoS2 (C-MoS2) on Fe3+/Fe2+ redox cycle was much higher than pure MoS2. Besides, the considerable removal of tetracycline (TC) under high salinity conditions (0-7.1%) was attributed to the dominant role of PMS nonradical oxidation pathways, including 1O2 and surface-bound radicals. The catalytic sites included Fe3+/Fe2+, Mo4+/Mo5+/Mo6+, C=O, pyridine N, pyrrolic N and hydroxyl groups. Finally, density functional theory (DFT) was employed to get the radical electrophilic attack sites and nucleophile attack sites of TC, and the results were consistent with the TC degradation products determined by HPLC-MS. This work would broaden the application of MoS2-based catalysts, especially for PMS catalytic removal of organic pollutants from high salinity wastewater.

Effect of superphosphate addition on heavy metals speciation and microbial communities during composting.

Superphosphate fertilizer (SSP) as an additive can reduce the nitrogen loss and increase available phosphorus in composting but few studies investigated the effect of SSP addition on heavy metal and microbial communities. In this study, different ratios (10%, 18%, 26%) of SSP were added into pig manure composting to assess the changes of heavy metal (Cu, Mn, As, Zn, and Fe) fractions, bacterial and fungal communities as well as their interactions. SSP addition at 18% had lower ecological risk but still increased the bioavailability of Cu, Mn, and Fe in composts compared to control. Adding 18% SSP into compost decreased bacterial number and increased the fungal diversity compared to CK. Redundancy analysis indicated heavy metal fractions correlated significantly with bacterial and fungal community compositions in composting with 18% SSP. Network analysis showed adding 18% SSP increased microbial interaction and positive cooperation especially enhanced the proportion of Proteobacteria and Ascomycota.

One-pot synthesis of N-doped carbon intercalated molybdenum disulfide nanohybrid for enhanced adsorption of tetracycline from aqueous solutions.

Nitrogen-doped carbon intercalated molybdenum disulfide nanohybrid (NC-MoS2) with well-interconnected nanosheets was successfully fabricated using a one-pot hydrothermal method and applied as a novel adsorbent to remove tetracycline (TC) from aqueous solutions. Series material characterizations indicated that the intercalation of nitrogen-doped carbon into MoS2 nanosheets could produce widened interlayer spacing, enlarge the specific surface area and create more extensive functional groups. The adsorption kinetics and isotherms investigations revealed that the pseudo-second-order model and Langmuir isotherm model could fit well the TC adsorption behavior of NC-MoS2. Particularly, NC-MoS2 possessed a high maximum adsorption capacity (1128.4 mg/g) that was approximately 2.8 times that of pristine MoS2 (409.84 mg/g) at 308 K and pH = 6.0 ± 0.1. Furthermore, the relevant thermodynamic parameters indicated that the adsorption process was spontaneous and endothermic. The adsorption process was dependent on multiple interactions including hydrophobicity, π-π stacking interaction and hydrogen bond. These findings demonstrated that NC-MoS2 had potential applications for treating TC-containing water and broadened the application of metal sulfides in the environmental field.

miR-181a-5p inhibits the proliferation and invasion of drug-resistant glioblastoma cells by targeting F-box protein 11 expression.

Glioblastoma (GBM) is the most common malignant primary tumor in the human central nervous system. The present study aimed to explore the molecular mechanism by which microRNA (miR)-181a-5p targets the F-box protein 11 (FBXO11) in glioma cells to inhibit cell proliferation and invasion. Reverse transcription-quantitative (RT-q)PCR was performed to detect the expression levels of miR-181a-5p in U251TR cells, U251 cells, primary GBM tissues and relapsed GBM tissues in order to determine the association between miR-181a-5p and the chemoresistance of GBM cells. The expression levels of miR-181a-5p in GBM cells were modulated via transfecting miR-181a-5p mimics and inhibitors. Cell Counting Kit-8 assays were undertaken to assess the effects of miR-181a-5p on drug sensitivity and proliferation of GBM cells. Wound healing assays were performed to examine the effects of miR-181a-5p on the migratory ability of GBM cells. Furthermore, the effects of miR-181a-5p on the invasive ability of GBM cells were analyzed using an in vitro invasion assay. Flow cytometry analysis was carried out to determine whether overexpression of miR-181a-5p can promote the apoptotic rate of GBM cells. RT-qPCR and western blotting were employed to detect the effects of miR-181a-5p on mRNA and protein expression of FBX011. miR-181a-5p exhibited low expression in resistant GBM cell lines and recurrent tumor tissues. Dual-luciferase reporter assays were utilized to detect luciferase activity to verify the targeted regulatory association between miR-181a-5p and FBXO11. Upregulation of miR-181a-5p promoted the sensitivity of GBM cells to temozolomide (TMZ), increased the apoptotic rate of GBM cells and significantly inhibited the invasive and migratory capacities of GBM cells. In drug-resistant glioma cells, compared with the miR-negative control group and the blank group, the expression of miR-181a-5p was significantly upregulated (P<0.01), while the expression of FBXO11 protein was downregulated. miR-181a-5p increased the sensitivity of GBM cells to TMZ. miR-181a-5p significantly inhibited the migratory and invasive capacities of GBM cells. miR-181a-5p may become a novel effective target for the treatment of GBM. The results of dual-luciferase reporter assays indicated that miR-181a-5p could target the 3'-untranslated region of FBXO11. The underlying mechanism may be targeted inhibition of FBXO11 gene expression, or may be associated with apoptosis.

SPARC Knockdown Reduces Glutamate-Induced HT22 Hippocampal Nerve Cell Damage by Regulating Autophagy.

Secreted protein acidic and rich in cysteine (SPARC) is a matricellular protein involved in the extracellular matrix and interactions between cells during neural development of the central nervous system (CNS). Oxidative glutamate toxicity is involved in CNS diseases, including epilepsy, Alzheimer's disease, and ischemic stroke. However, the molecular mechanism of nerve injury is not fully understood in CNS diseases. Herein, the glutamate-induced nerve damage model was used to explore the molecular mechanisms affecting nerve damage. The levels of SPARC and autophagy were increased in glutamate-induced HT22 hippocampal nerve injury. In summary, the current study confirmed that SPARC regulates autophagy in HT22 hippocampal nerve cells, and its knockdown reduces the glutamate-induced HT22 hippocampal nerve injury by inhibiting autophagy. These findings suggested that SPARC plays a crucial role in nerve injury of CNS diseases.

Singlet oxygen dominated peroxymonosulfate activation by CuO-CeO2 for organic pollutants degradation: Performance and mechanism.

In this study, CuO-CeO2 was synthesized via an easy hydrothermal-calcination method and innovatively applied to peroxymonosulfate (PMS) activation for pollutants degradation under a non-radical oxidation pathway. Singlet oxygen (1O2) was the dominated reactive oxygen species in the CuO-CeO2/PMS system, leading to a dramatical degradation efficiency with Rhodamine B (RhB) as model compounds. The observed rate constant of the CuO-CeO2/PMS system was 7-11 times higher than that of only PMS, CeO2/PMS and CuO/PMS systems. Also, under the reaction conditions of 1.6 mM PMS, 0.4 g/L catalyst and initial pH 7, the degradation efficiencies of RhB, Methylene Blue, Reactive Blue 19 and atrazine were respectively up to 100%, 85.39%, 72.84% and 98.44% in 60 min. X-ray photoelectron microscopy analysis indicated that the electrons transfer between CuO and CeO2 and the formation of oxygen vacancy in CeO2 should be responsible for the enhanced 1O2 production, which involved a new non-radical oxidation pathway for PMS activation by CuO-CeO2 catalyst. Moreover, the combination of CuO and CeO2 increased reusability and stability of catalyst, allowing it remove more than 92% of RhB over a wide pH range (pH = 3-9). This study not only proved that CuO-CeO2 is an efficient and stable PMS activator but also provided a new insight into PMS activation through a non-radical oxidation pathway for organic contaminants removal from wastewater.