Chloroplast genomes of Caragana tibetica and Caragana turkestanica: structures and comparative analysis.

BACKGROUND: The genus Caragana encompasses multiple plant species that possess medicinal and ecological value. However, some species of Caragana are quite similar in morphology, so identifying species in this genus based on their morphological characteristics is considerably complex. In our research, illumina paired-end sequencing was employed to investigate the genetic organization and structure of Caragana tibetica and Caragana turkestanica, including the previously published chloroplast genome sequence of 7 Caragana plants. RESULTS: The lengths of C. tibetica and C. turkestanica chloroplast genomes were 128,433 bp and 129,453 bp, respectively. The absence of inverted repeat sequences in these two species categorizes them under the inverted repeat loss clade (IRLC). They encode 110 and 111 genes (4 /4 rRNA genes, 30 /31tRNA genes, and 76 /76 protein-coding genes), respectively. Comparison of the chloroplast genomes of C. tibetica and C. turkestanica with 7 other Caragana species revealed a high overall sequence similarity. However, some divergence was observed between certain intergenic regions (matK-rbcL, psbD-psbM, atpA-psbI, and etc.). Nucleotide diversity (π) analysis revealed the detection of five highly likely variable regions, namely rps2-atpI, accD-psaI-ycf4, cemA-petA, psbN-psbH and rpoA-rps11. Phylogenetic analysis revealed that C. tibetica's sister species is Caragana jubata, whereas C. turkestanica's closest relative is Caragana arborescens. CONCLUSIONS: The present study provides worthwhile information about the chloroplast genomes of C. tibetica and C. turkestanica, which aids in the identification and classification of Caragana species.

Chloroplast genome analyses of Caragana arborescens and Caragana opulens.

BACKGROUND: Numerous species within the genus Caragana have high ecological and medicinal value. However, species identification based on morphological characteristics is quite complicated in the genus. To address this issue, we analyzed complete plastid genome data for the genus. RESULTS: We obtained chloroplast genomes of two species, Caragana arborescens and Caragana opulens, using Illumina sequencing technology, with lengths of 129,473 bp and 132,815 bp, respectively. The absence of inverted repeat sequences in the two species indicated that they could be assigned to the inverted repeat-lacking clade (IRLC). The genomes included 111 distinct genes (4 rRNA genes, 31 tRNA genes, and 76 protein-coding genes). In addition, 16 genes containing introns were identified in the two genomes, the majority of which contained a single intron. Repeat analyses revealed 129 and 229 repeats in C. arborescens and C. opulens, respectively. C. arborescens and C. opulens genomes contained 277 and 265 simple sequence repeats, respectively. The two Caragana species exhibited similar codon usage patterns. rpl20-clpP, rps19-rpl2, and rpl23-ycf2 showed the highest nucleotide diversity (pi). In an analysis of sequence divergence, certain intergenic regions (matK-rbcL, psbM-petN, atpA-psbI, petA-psbL, psbE-petL, and rps7-rps12) were highly variable. A phylogenetic analysis showed that C. arborescens and C. opulens were related and clustered together with four other Caragana species. The genera Astragalus and Caragana were relatively closely related. CONCLUSIONS: The present study provides valuable information about the chloroplast genomes of C. arborescens and C. opulens and lays a foundation for future phylogenetic research and molecular marker development.

Z-Type Heterojunction MnO2@g-C3N4 Photocatalyst-Activated Peroxymonosulfate for the Removal of Tetracycline Hydrochloride in Water.

A Z-type heterojunction MnO2@g-C3N4 photocatalyst with excellent performance was synthesized by an easy high-temperature thermal polymerization approach and combined with peroxymonosulfate (PMS) oxidation technology for highly efficient degrading of tetracycline hydrochloride (TC). Analysis of the morphological structural and photoelectric properties of the catalysts was achieved through different characterization approaches, showing that the addition of MnO2 heightened visible light absorption by g-C3N4. The Mn1-CN1/PMS system showed the best degradation of TC wastewater, with a TC degradation efficiency of 96.97% following 180 min of treatment. This was an approximate 38.65% increase over the g-C3N4/PMS system. Additionally, the Mn1-CN1 catalyst exhibited excellent stability and reusability. The active species trapping experiment indicated •OH and SO4•- remained the primary active species to degrade TC in the combined system. TC degradation pathways and intermediate products were determined. The Three-Dimensional Excitation-Emission Matrix (3DEEM) was employed for analyzing changes in the molecular structure in TC photocatalytic degradation. The biological toxicity of TC and its degradation intermediates were investigated via the Toxicity Estimation Software Test (T.E.S.T.). The research offers fresh thinking for water environment pollution treatment.

Effects of microplastics on the properties of different types of sewage sludge and strategies to overcome the inhibition: A review.

Microplastics have been identified as an emerging pollutant. When microplastics enter wastewater treatment plants, the plant traps most of the microplastics in the sludge during sewage treatment. Therefore, the effects of microplastics on sludge removal performance, and on the physical and chemical properties and microbial communities in sludge, have attracted extensive attention. This review mainly describes the presence of microplastics in wastewater treatment plants, and the effects of microplastics on the decontamination efficiency and physicochemical properties of activated sludge, aerobic granular sludge, anaerobic granular sludge and anaerobic ammonium oxidation sludge. Further, the review summarizes the effects of microplastics on microbial activity and microbial community dynamics in various sludges in terms of type, concentration, and contact time. The mechanisms used to strengthen the reduction of microplastics, such as biochar and hydrochar, are also discussed. This review summarizes the mechanism by which microplastics influence the performance of different types of sludge, and proposes effective strategies to mitigate the inhibitive effect of microplastics on sludge and discusses removal technologies of microplastics in sewage. Biochar and hydrochar are one of the effective measures to overcome the inhibition of microplastics on sludge. Meanwhile, constructed wetland may be one of the important choice for the future removal of microplastics from sewage. The goal is to provide theoretical support and insights for ensuring the stable operation of wastewater treatment plants and reducing the impact of microplastics on the environment.

Performance and microbial metabolic mechanism of imidacloprid removal in a microbial electrolysis cell-integrated adsorption biological coupling system.

Coke used as a filler to treat imidacloprid (IMI) wastewater by both adsorption biological coupling and microbial electrolysis cells (MEC)-adsorption biological coupling technologies, the removal efficiencies on pollutions in wastewater containing IMI were investigated, and the key functional genes related to IMI degradation pathways were also revealed. Results showed that the removal rates of COD, ammonia nitrogen, TP, and IMI under the adsorption biological coupling treatment and MEC-adsorption biological coupling treatment were 94.61-95.54%, 93.37-95.79%, 73.69-83.80%, and 100%, respectively. MEC increased the relative abundance of Proteobacteria by 9.01% and transformed the dominant bacteria from Lysobacter and Reyranella to Brevundimonas and Aquincola. Moreover, MEC up-regulated the abundance of the coding genes PK (9.30%), narG (2.26%), pstS (3.63%), and phnD (1.32%), and converted the IMI degradation products to smaller molecular weight C6H8N2 and C6H6ClNO. This study provided an important reference information for efficient treatment of IMI wastewater using the MEC-adsorption biological coupling technology.

Effects of perfluoroalkyl substances on the operational efficiency, microbial communities, and key metabolic pathways of constructed rapid infiltration system with coke as filler layer.

Influences of perfluoroalkyl substances on the performance and microbial metabolic pathways of constructed rapid infiltration systems are not fully understood. In this study, wastewater containing different concentrations of perfluorooctanoic acid (PFOA)/perfluorobutyric acid (PFBA) was treated in constructed rapid infiltration systems with coke as filler. The addition of 5 and 10 mg/L PFOA inhibited the removal of chemical oxygen demand (COD) (80.42%, 89.27%), ammonia nitrogen (31.32%, 41.14%), and total phosphorus (TP) (43.30%, 39.34%). Meanwhile, 10 mg/L PFBA inhibited TP removal of the systems. Based on X-ray photoelectron spectroscopy, the percentages of F- within the PFOA and PFBA groups were 12.91% and 48.46%, respectively. PFOA transformed Proteobacteria (71.79%) into the dominant phyla of the systems, whereas PFBA enriched Actinobacteria (72.51%). The PFBA up-regulated the coding gene of 6-phosphofructokinase by 14.44%, whereas PFOA down-regulated it by 4.76%. These findings provide insights into the toxicity of perfluoroalkyl substances on constructed rapid infiltration systems.

Development of the "hidden" multi-target-directed ligands by AChE/BuChE for the treatment of Alzheimer's disease.

Accumulation of evidences suggested that excessive amounts of AChE and BuChE in the brain of AD patients at the different stage of AD, which could hydrolyze ACh and accelerated Aß aggregation. To develop new "hidden" multifunctional agents through AChE/BuChE would be a promising strategy to treat AD. To this end, firstly, a series of chalcone derivatives with chelating property was designed and synthesized. The in vitro results showed that compound 3f indicated significant selective MAO-B inhibitory activity (IC50 = 0.67 µM) and remarkable anti-inflammatory property. It also significantly inhibited self-induced Aß1-42 aggregation and showed remarkable neuroprotective effects on Aß25-35-induced PC12 cell injury. Furthermore, compound 3f was a selective metal chelator and could inhibit Cu2+-induced Aß1-42 aggregation. Based on this, the carbamate fragment was introduced to compound 3f to obtain carbamate derivatives. The biological activity results exhibited that compound 4b showed good BBB permeability, good AChE inhibitory potency (IC50 = 5.3 µM), moderate BuChE inhibitory potency (IC50 = 12.4 µM), significant MAO-B inhibitory potency, anti-inflammation potency on LPS-induced BV-2 cells and neuroprotective effects on Aß25-35-induced PC12 cell injury. Compared with 3f, compound 4b did not show obvious chelation property. Significantly, compound 4b could be activated by AChE/BuChE following inhibition of AChE/BuChE to liberate an active multifunctional chelator 3f, which was consistent with our original intention. More importantly, compounds 3f and 4b presented favorable ADME properties and good stability in artificial gastrointestinal fluid, blood plasma and rat liver microsomes. The in vivo results suggested that compound 4b (0.0195 µg/mL) could significantly improve dyskinesia and reaction capacity of the AlCl3-induced zebrafish AD model by increasing the level of ACh. Together our data suggest that compound 4b was a promising "hidden" multifunctional agent by AChE/BuChE, and this strategy deserved further development for the treatment of AD.

Schiff base modified starch: A promising biosupport for palladium in Suzuki cross-coupling reactions.

Starch can be used in diverse fields because it is a readily available, non-toxic polysaccharide with adaptable functionality and biodegradability. In this study, taking the aforementioned characteristics into consideration, we designed a modified starch (Starch-SB), which serves as supporting material for palladium stabilization. This new air and moisture-stable robust palladium composite [Starch-SB-Pd(II)] was characterized by FT-IR, XRD, TGA, XPS, SEM, EDX, TEM, CP/MAS 13C NMR, and ICP-MS analytical techniques. The catalytic studies exhibit high activity (up to 99 %) and stability in Suzuki cross-coupling reactions for this starch supported catalytic system under mild conditions (lower reaction temperature and green solvents) because of the cooperative interactions of multifunctional capturing sites on starch (Schiff base, hydroxy and amine groups) with palladium species. The experiments on reusability demonstrate that Starch-SB-Pd(II), which was prepared from functionalized starch, could be readily recycled several cycles through centrifugation. Moreover, we proposed a possibly multifunctional complex structure. This work presents an appealing and intriguing pathway for the utilization of polysaccharide as crucial support in green chemical transformations.

Comprehensive Analysis of m5C Methylation Regulatory Genes and Tumor Microenvironment in Prostate Cancer.

Background: 5-Methylcytidine (m5C) methylation is an emerging epigenetic modification in recent years, which is associated with the development and progression of various cancers. However, the prognostic value of m5C regulatory genes and the correlation between m5C methylation and the tumor microenvironment (TME) in prostate cancer remain unknown. Methods: In the current study, the genetic and transcriptional alterations and prognostic value of m5C regulatory genes were investigated in The Cancer Genome Atlas and Gene Expression Omnibus datasets. Then, an m5C prognostic model was established by LASSO Cox regression analysis. Gene set variation analyses (GSVA), gene set enrichment analysis (GSEA), clinical relevance, and TME analyses were conducted to explain the biological functions and quantify the TME scores between high-risk and low-risk subgroups. m5C regulatory gene clusters and m5C immune subtypes were identified using consensus unsupervised clustering analysis. The Cell-type Identification By Estimating Relative Subsets of RNA Transcripts algorithm was used to calculate the contents of immune cells. Results: TET3 was upregulated at transcriptional levels in PCa compared with normal tissues, and a high TET3 expression was associated with poor prognosis. An m5C prognostic model consisting of 3 genes (NSUN2, TET3, and YBX1) was developed and a nomogram was constructed for improving the clinical applicability of the model. Functional analysis revealed the enrichment of pathways and the biological processes associated with RNA regulation and immune function. Significant differences were also found in the expression levels of m5C regulatory genes, TME scores, and immune cell infiltration levels between different risk subgroups. We identified two distinct m5C gene clusters and found their correlation with patient prognosis and immune cell infiltration characteristics. Naive B cells, CD8+ T cells, M1 macrophages and M2 macrophages were obtained and 2 m5C immune subtypes were identified. CTLA4, NSUN6, TET1, and TET3 were differentially expressed between immune subtypes. The expression of CTLA4 was found to be correlated with the degree of immune cell infiltration. Conclusions: Our comprehensive analysis of m5C regulatory genes in PCa demonstrated their potential roles in the prognosis, clinical features, and TME. These findings may improve our understanding of m5C regulatory genes in the tumor biology of PCa.

Effect of asparagine, corncob biochar and Fe(II) on anaerobic biological treatment under low temperature: Enhanced performance and microbial community dynamic.

To ensure the efficiency of anaerobic biological treatment technology at lower temperature will expand the application of anaerobic reactor in practical industrial wastewater treatment. Through a batch experiment, asparagine, corncob biochar and Fe2+ were selected as strengthening measures to analyze the effects on the anaerobic sludge characteristics, microbial community and functional genes in the low temperature (15 °C). Results showed that after 21 days, asparagine began to promote chemical oxygen demand (COD) removal by the anaerobic treatment, with highest COD removal rate (81.65%) observed when the asparagine concentration was 1 mmol/L. When adding 3 g biochar, 25 mg/L Fe2+, and the combination of biochar and Fe2+, the COD removal rates reached to 82%, 92% and 97%, respectively. In the presence of asparagine, both biochar and Fe2+ alone or in combination increased the activity of protease (16.35%-120.71%) and coenzyme F420 (5.63%-130.2%). The relative abundance of Proteobacteria and Methanobacterium increased in the presence of biochar and Fe2+. In addition, the KEGG results showed that the combined addition of biochar and Fe2+ enhanced bacterial replication and repair and promoted amino acid metabolism of archaea.

Compound heterozygosity for novel variations of the NHLRC1 Gene in a family with Lafora disease.

PURPOSE: NHLRC1 gene mutations are present in a varied proportion of patients with Lafora disease (LD). Compound heterozygosity for novel variations of the gene has been reported in progressive Lafora myoclonic epilepsy of Lafora pedigree. METHODS: The clinical data of the cases were collected for diagnosis, and the genetic spectrum of the family was confirmed. For molecular diagnosis, whole-exome sequencing (WES) of the pedigree was performed. RESULTS: A novel biallelic compound heterozygous c.333dupC chr6-18122504 (p.(Gly112ArgfsTer44)) and c.612dupT chr6-18122225 (p.(Gly205Trpfs*29)) mutation in the NHLRC1 gene was identified in our progressive myoclonic epilepsy of Lafora pedigree. CONCLUSIONS: The genetic analysis was useful for the diagnosis of LD. Genetic analysis is recommended for patients and close relatives, and tissue biopsy is an alternative.

Development of naringenin-O-alkylamine derivatives as multifunctional agents for the treatment of Alzheimer's disease.

In this study, a series of naringenin-O-alkylamine derivatives were designed and obtained by introducing an alkylamine fragment into the naringenin skeleton. The in vitro biological activity results revealed that compounds 5f and 7k showed good antioxidant activity with ORAC values of 2.3eq and 1.2eq, respectively. Compounds 5f and 7k were reversible and excellent huAChE inhibitors with IC50 values of 0.91 µM and 0.57 µM, respectively. Moreover, compounds 5f and 7k could inhibit self-induced Aß1-42 aggregation with 62.1% and 43.8% inhibition rate, respectively, and significantly inhibited huAChE-Aß1-40 aggregation with 51.7% and 43.4% inhibition rate, respectively. In addition, compounds 5f and 7k were selective metal chelators and remarkably inhibited Cu2+-induced Aß1-42 aggregation with 73.5% and 68.7% inhibition rates, respectively. Furthermore, compounds 5f and 7k could cross the blood-brain barrier in vitro and displayed good neuroprotective effects and anti-inflammatory properties. Further investigation showed that compound 5f did not show obvious hepatotoxicity and displayed a good hepatoprotective effect by its antioxidant activity. The in vivo study displayed that compound 5f significantly improved scopolamine-induced mice memory impairment. Therefore, compound 5f was a potential multifunctional candidate for the treatment of AD.

The TLR4 mediated inflammatory signal pathway might be involved in drug resistance in drug-resistant epileptic rats.

Background Recent data suggested that inflammatory responses are involved in the acute or chronic phase of drug-resistant epilepsy. The aim of this study was to examine the signal pathway of Toll-like receptors (TLR) 4 mediated drug resistance in refractory epileptic rats. Methods Lithium chloride and pilocarpine were used to establish a drug-resistant epilepsy rat model. Recombinant adenovirus was used to construct a TLR4 deficient drug-resistant epileptic rat model. The expression of TLR4, p-gp, interleukin (IL)-1ß, tumor necrosis factor (TNF)-α, and nuclear factor kappa B (NF-κB) were determined by Western blot and Immunohistochemical analysis. Results P-gp, TLR4, NF-κB, IL-1ß, TNF-α were significantly higher in the drug-resistant epileptic rats than in the epileptic rats (all P < 0.05). Contrary, this process was reversed in TLR4-deficient epileptic rats. The expression levels of P-gp, TLR4, NF-κB, IL-1ß, and TNF-α expression were significantly inhibited in TLR4-deficient rats, suggesting that TLR4, as an important upstream factor, might significantly affect the expression levels of P-gp, NF-κB, IL-1ß, and TNF-α (all P < 0.05). Conclusions Our study found the expression levels of TLR4, NF-κB, IL-1ß, TNF-α which were related with inflammatory signal pathway changed in drug resistant epileptic rats. Our results suggest that TLR4, as an upstream regulator, could activate the downstream NF-κB, regulate inflammatory factors IL-1ß, TNF-α, and other cytokines, and affect the expression level of P-gp in drug resistant epileptic rats. We speculate TLR4 related inflammatory signal pathway might take part in the emergence of epilepsy resistance, which is important in drug resistance.

Photo-induced programmable degradation of carboxymethyl chitosan-based hydrogels.

Hydrogels are widely used in the biomedical field, due to their high similarity to native extracellular matrix (ECM). Most responsive hydrogels could only passively receive stimuli and independently change their properties. In this study, a photosensitive o-nitrobenzyl (NB) ester linker of polyethylene glycol (PEG) with maleimido (Mal) as terminal groups (PEG-NB-Mal) and a 5-methylfurfuryl (mF) grafted carboxymethyl chitosan (CMCS) derivative (CMCS-mF) were synthesized and used to prepare functional hydrogels via Diels-Alder (DA) reactions. The hydrogel exhibited programmable degradation properties after sequential exposure to UV light and acid treatments. It can maintain high integrity upon the single stimuli, the cascade acid and UV light treatments or the cascade UV light and alkaline treatments. Moreover, the hydrogel exhibited well controlled release profile of rhodamine B (RB). In summary, such CMCS-based hydrogels show great potential in biomedical applications. In addition, the usage of photo-induced cascade reaction in sequential degradation hydrogels can be extended to design other types of programmable smart materials.

Investigation of photocatalysis reactions on the single-crystal and polycrystalline graphenes.

Graphene has been extensive studied in the field of photocatalysis. Herein, single-crystal and polycrystalline graphenes are prepared by mechanical exfoliation and chemical vapor deposition (CVD), respectively. The photocatalytic properties of polycrystalline graphene are carefully assessed by using 4-nitrobenzenethiol (4-NBT), as a probe molecule, under incident 532 nm laser beam. Similarly, the photocatalytic properties of single-crystal graphene are also investigated with 4-aminothiophenol (PATP) under incident 633 nm laser radiation. In order to solve the problem of uneven distribution of probe molecules on graphene, the internal standard method is adopted by using 2-naphthalenethiol (2-NT), as the internal standard molecule. The experimental findings indicate that PATP can be catalyzed onto the surface of single-crystal graphene under the irradiation of 633 nm laser beam and its catalytic properties significantly increase with decreasing the number of graphene layers. In addition, when single-crystal graphene is used as the Surface-enhanced Raman scattering (SERS) enhancement substrate, the SERS enhancement was also increased with the decrease of the number of layers.

Influence of polyether sulfone microplastics and bisphenol A on anaerobic granular sludge: Performance evaluation and microbial community characterization.

The retention of polyether sulfone (PES) and bisphenol A (BPA) in wastewater has received extensive attention. The effects of PES and BPA on the removal of organic matter by anaerobic granular sludge were investigated. We also analyzed the changes in the electron transport system and the effects on the composition of extracellular polymeric substances (EPS), as well as alternations of the microbial community in the anaerobic granular sludge. In the experimental groups which received BPA, the removal of the chemical oxygen demand (COD) were significantly suppressed, which an average removal efficiency of less than 65%, 30% lower than that of the control group. In the loosely-bound EPS (LB-EPS) excitation-emission matrix (EEM) spectra, the absorption peak of tryptophan disappeared when the BPA pollutants was added, which it was present in the control group without added pollutants. The addition of PES and BPA also affected protease, acetate kinase, and coenzyme F420 activities in the anaerobic granular sludge. Especially, the coenzyme F420 reduced from 0.0045 to 0.0017 µmol/L in the presence of PES and BPA. The relative abundance of Spirochaetes decreased in the presence of PES and BPA, while the relative abundance of Bacteroidetes increased from 12.98% to 22.87%. At the genus level, in the presence of PES and BPA, the relative abundance of Acinetobacter increased from 2.20% to 9.64% and Hydrogenophaga decreased sharply from 15.58% to 0.12%.

Ru-Pd Thermoresponsive Nanocatalyst Based on a Poly(ionic liquid) for Highly Efficient and Selectively Catalyzed Suzuki Coupling and Asymmetric Transfer Hydrogenation in the Aqueous Phase.

The development of intelligent polymeric materials to precisely control the catalytic sites of heterogeneous catalysts and enable highly efficient catalysis of a cascade reaction is of great significance. Here, the utilization of a polymer ionic liquid (PIL) containing two different anions facilitates the preparation of Ru-Pd catalysts with controllable phase transition temperatures and hydrophilic and hydrophobic surfaces. The combined multifunctionality, synergistic effects, micellar effects, aggregation effects, and temperature responsiveness of the nanocatalyst render it suitable for promoting selectively catalyzed Suzuki coupling and asymmetric transfer hydrogenation in water. Above the lower critical solution temperature (LCST) of the catalyst, it catalyzes only the coupling reaction with a high turnover number (TON) of up to 999.0. Below the LCST, the catalyst catalyzes only the asymmetric transfer hydrogenation with good catalytic activity and enantioselectivity. It is important that the catalyst can be simply and effectively recovered and recycled at least 10 times without significant loss of catalytic activity and enantioselectivity. This study also highlights the superiority of multifunctional heterogeneous catalysts based on PILs, which not only overcome limitations associated with low activity of heterogeneous catalysts but also realize selective reactions according to a temperature change, thereby improving the reactivity and enantioselectivity in multiple organic transformations.

A facile and green strategy to simultaneously enhance the flame retardant and mechanical properties of poly(vinyl alcohol) by introduction of a bio-based polyelectrolyte complex formed by chitosan and phytic acid.

There are still some key problems in the process of the flame retardant treatment of poly vinyl alcohol (PVA): poor compatibility, deteriorating mechanical properties and potential toxicity to human health and environment. To solve these issues, a green and eco-friendly bio-based polyelectrolyte complex (PEC) formed by chitosan and phytic acid was designed to enhance the flame retardant and mechanical properties of PVA by a facile ultrasonic-assisted solution blending method. Moreover, the mechanical and flame retardant properties could be regulated by varying the ratio of each component in the PEC. Thermogravimetric analysis (TGA) indicated that after the introduction of PEC, PVA/PEC composites maintained better thermal stability and char formation ability. Besides, when the addition of PEC reached 20 wt%, the limited oxygen index (LOI) value of cured PVA increased from 18% to 25.9%, 30.8% and 35.6% for PVA/20(2 : 1) PEC, PVA/20(1 : 2) PEC and PVA/20(1 : 8) PEC, respectively. Moreover, UL-94 V-0 rating was achieved except for the PVA/20(2 : 1) PEC. Compared with pure PVA, the peak heat release rate (pHRR) and the total heat release (THR) of PVA/20(1 : 8) PEC demonstrated a sharp decrease by 69.9% and 45.5%, respectively, in the microscale combustion calorimeter measurements (MCC). These results indicate that PEC can endow PVA with excellent flame retardancy. Furthermore, the microscopic investigations on char residues of all samples by scanning electron microscopy, Fourier transform infrared spectra and Raman spectroscopy revealed the possible flame retardant mechanisms in condensed and gaseous phases. In addition, PVA/PEC composites have better mechanical properties owing to their harder backbones of chitosan, formation of phosphonate bonds and the PVA molecular chain movement blocked by PEC. As a result, the facile processing technology and eco-friendly flame retardants are expected to be applied in practice.

Effects of exposure to polyether sulfone microplastic on the nitrifying process and microbial community structure in aerobic granular sludge.

The effects of polyether sulfone (PES) microplastic concentration on the nitrifying process of aerobic granular sludge (AGS) were investigated together with the microbial community structure of AGS. The PES microplastic concentration inhibited the removal of ammonia nitrogen only to a small extent. The average total nitrogen removal rate increased by 5.6% after PES addition. On the 30th day, the addition of 0.5 g/L PES inhibited the specific nitrate reduction rate (SNRR) by 38.84 mg N/(g MLSS·h). Nitrite oxidase (NOR) performance of the AGS were inhibited with addition the PES. According to the high-throughput sequencing results, in the presence of PES, the abundance of Bacillales_Incertae Sedis XII reduced, while the abundance of Anaerolineaceaen increased in the AGS. According to the clusters of orthologous groups (COG) and kyoto encyclopedia of genes and genomes (KEGG), the content of cytochrome c-containing reduced and the Amino Acid Metabolism increased with addition 0.5 g/L PES microplastic.