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The presence of microplastics in aquatic ecosystems is of increasing global concern. This study investigated ingestion, egestion and acute effects of polyethylene microplastics in Daphnia magna . Fate of regular shaped microplastic beads (10–106 µm) were compared with irregular shaped microplastic fragments (10–75 µm). Daphnia magna ingested regular and irregular microplastic with uptake between 0.7 and 50 plastic particles/animal/day when exposed to microplastic concentrations of 0.0001–10 g/L. Egestion of irregular fragments was slower than that of microplastic beads. The EC50 for irregular microplastic was 0.065 g/L whereas microplastic beads were less inhibitory. The potential of microplastic to act as vector for hydrophobic pollutants was examined using [ 14 C]phenanthrene as tracer. Polyethylene microplastic sorbed less [ 14 C]phenanthrene compared to natural plankton organisms (bacteria, algae, yeast). As microplastics are much less abundant in most aquatic ecosystems compared to plankton organisms this suggests a limited role as vector for hydrophobic pollutants under current environmental conditions.

The adsorption of phenanthrene onto activated carbons produced from Vitis vinifera leaf litter (a waste plant biomass) was investigated in this study. Zinc chloride ( ZnCl2) and phosphoric acid ( H3PO4) were utilised as activating agents in producing the activated carbons. The characterisation of the activated carbons was achieved with Fourier transform infrared spectroscopy (for surface functional groups), scanning electron microscopy (for surface morphology) and Brunauer–Emmett–Teller (BET) (for surface area determination). The adsorption of phenanthrene onto the activated carbons was optimised in terms of solution pH, adsorbent dosage, initial concentration of adsorbate solution and contact time. Experimental results showed that H3PO4 modified activated carbon gave better yield (up to 58.40%) relative to ZnCl2 modified activated carbon (only up to 47.08%). Meanwhile, surface characterisation showed that ZnCl2 modification resulted in higher BET surface area (up to 616.60 m2/ g) and total pore volume (up to 0.289 cm3/g) relative to BET surface area of up to 295.49 m2/ g and total pore volume of up to 0.185 cm3/g obtained from H3PO4 modified activated carbons. Adsorption equilibrium data fitted well into Freundlich isotherm model relative to other applied isotherm models, with maximum Kf value of 1.27 for ZnCl2 modified activated carbon and 1.16 Kf value for H3PO4 modified activated carbon. The maximum adsorption capacity for ZnCl2 and H3PO4 activated carbons for the removal of phenanthrene were 94.12 and 89.13 mg/g, respectively. Kinetic studies revealed that dynamic equilibrium was reached at 80 min contact time. Experimental data fitted best into the Elovich kinetic model relative to other kinetic models, based on the correlation coefficient (R2) values obtained from kinetic studies. Chemisorption was deduced as a major phenanthrene removal pathway from aqueous solution and the physicochemical characteristics of the adsorbents have major influence on phenanthrene removal efficiencies. KCI Citation Count: 0

Environmental contamination from petroleum refinery operations has increased due to the rapid population growth and modernization of society, necessitating urgent repair. Microbial remediation of petroleum wastewater by prominent bacterial cultures holds promise in circumventing the issue of petroleum-related pollution. Herein, the bacterial culture was isolated from petroleum-contaminated sludge samples for the valorization of polyaromatic hydrocarbons and biodegradation of petroleum wastewater samples. The bacterial strain was screened and identified as Bacillus subtilis IH-1. After six days of incubation, the bacteria had degraded 25.9% of phenanthrene and 20.3% of naphthalene. The treatment of wastewater samples was assessed using physico-chemical and Fourier-transform infrared spectroscopy analysis, which revealed that the level of pollutants was elevated and above the allowed limits. Following bacterial degradation, the reduction in pollution parameters viz. EC (82.7%), BOD (87.0%), COD (80.0%), total phenols (96.3%), oil and grease (79.7%), TKN (68.8%), TOC (96.3%) and TPH (52.4%) were observed. The reduction in pH and heavy metals were also observed after bacterial treatment. V. mungo was used in the phytotoxicity test, which revealed at 50% wastewater concentration the reduction in biomass (30.3%), root length (87.7%), shoot length (93.9%), and seed germination (30.0%) was observed in comparison to control. When A. cepa root tips immersed in varying concentrations of wastewater samples, the mitotic index significantly decreased, suggesting the induction of cytotoxicity. However, following the bacterial treatment, there was a noticeable decrease in phytotoxicity and cytotoxicity. The bacterial culture produces lignin peroxidase enzyme and has the potential to degrade the toxic pollutants of petroleum wastewater. Therefore the bacterium may be immobilised or directly used at reactor scale or pilot scale study to benefit the industry and environmental safety.

Phenalenyl — a triangular neutral radical consisting of three adjacent benzene rings — and π -conjugated derivatives based on the same motif, can be viewed as 'open-shell graphene fragments'. This Perspective discusses their electronic-spin structures, the properties that arise from their unpaired electrons, and highlights their potential applications for molecular spin devices. Graphene, a two-dimensional layer of sp 2 -hybridized carbon atoms, can be viewed as a sheet of benzene rings fused together. Three benzene rings can be combined in three different ways, to yield linear anthracene and angular phenanthrene, where the rings share two C–C bonds, and the phenalenyl structure where three C–C bonds are shared between the rings. This third structure contains an uneven number of carbon atoms and, hence, in its neutral state, an uneven number of electrons — that is, it is a radical. All three structures may be viewed as being sections of graphene. Extension of this concept leads to an entire family of phenalenyl derivatives — 'open-shell graphene fragments' — that are of substantial interest from the standpoint of fundamental science as well as in view of their potential applications in materials chemistry, in particular quantum electronic devices. Here we discuss current trends and challenges in this field.

Colonization by polycyclic aromatic hydrocarbon (PAH)-degrading endophytic bacteria (PAHDEB) can reduce the PAH contamination risk in plant. However, little information is available on the impact of PAHDEB colonization on the endophytic bacterial community of inner plant tissues. A phenanthrene-degrading endophytic bacterium (PDEB), Massilia sp. Pn2, was inoculated onto the roots of wheat and subjected to greenhouse container experiments. The endophytic bacterial community structure in wheat was investigated using high-throughput sequencing technology. The majority of endophytic bacteria in wheat were Proteobacteria , and the dominant genus was Pseudomonas . Phenanthrene contamination clearly increased the diversity of endophytic bacteria in wheat. The cultivable endophytic bacteria counts in wheat decreased with increasing the level of phenanthrene contamination; the endophytic bacterial community structure changed correspondingly, and the bacterial richness first increased and then decreased. Inoculation of strain Pn2 reduced the phenanthrene contamination in wheat, enlarged the biomass of wheat roots, changed the bacterial community structure and enhanced the cell counts, diversity and richness of endophytic bacteria in phenanthrene-contaminated wheat in a contamination level-dependent manner. The findings of this investigation provide insight into the responses of endophytic bacterial community in plant to external PAH contamination and PAHDEB colonization.

Bioelectrochemical systems (BESs) have great potential for treating wastewater containing polycyclic aromatic hydrocarbons (PAHs); however, detailed data on cell physiological activities in PAH biodegradation pathways stimulated by BESs are still lacking. In this paper, a novel BES device was assembled to promote the growth of Pseudomonas sp. DGYH-12 in phenanthrene (PHE) degradation. The results showed that in the micro-electric field (0.2 V), cell growth rate and PHE degradation efficiency were 22% and 27.2% higher than biological control without electric stimulation (BC), respectively. The extracellular polymeric substance (EPS) concentration in BES (39.38 mg L −1 ) was higher than control (33.36 mg L −1 ); moreover, the membrane permeability and ATPase activities were also enhanced and there existing phthalic acid and salicylic acid metabolic pathways in the strain. The degradation genes nahAc , pcaH , and xylE expression levels were upregulated by micro-electric stimulation. This is the first study to analyze the physiological and metabolic effect of micro-electric stimulation on a PHE-degrading strain in detail and systematically.

ObjectivesGlucocorticoids have anti-inflammatory, transrepression-mediated effects, although adverse events (AEs; transactivation-mediated effects) limit long-term use in patients with rheumatoid arthritis (RA). We evaluated the efficacy and safety of fosdagrocorat (PF-04171327), a dissociated agonist of the glucocorticoid receptor, versus prednisone or placebo.MethodsIn this 12-week, phase II, randomised controlled trial, 323 patients with moderate to severe RA were randomised 1:1:1:1:1:1:1 to fosdagrocorat (1 mg, 5 mg, 10 mg or 15 mg), prednisone (5 mg or 10 mg) or placebo, once daily. The primary endpoints (week 8) were American College of Rheumatology 20% improvement criteria (ACR20) responses, and percentage changes from baseline in biomarkers of bone formation (procollagen type 1 N-terminal peptide [P1NP]) and resorption (urinary N-telopeptide to urinary creatinine ratio [uNTx:uCr]). Safety was assessed.ResultsACR20 responses with fosdagrocorat 10 mg and 15 mg were superior to placebo, and fosdagrocorat 15 mg was non-inferior to prednisone 10 mg (week 8 model-predicted ACR20 responses: 47%, 61%, 69% and 73% vs 51%, 71% and 37% with fosdagrocorat 1 mg, 5 mg, 10 mg and 15 mg vs prednisone 5 mg, 10 mg and placebo, respectively). Percentage changes from baseline in P1NP with fosdagrocorat 1 mg, 5 mg and 10 mg met non-inferiority criteria to prednisone 5 mg. Corresponding changes in uNTx:uCr varied considerably. All fosdagrocorat doses reduced glycosylated haemoglobin levels. AEs were similar between groups; 63 (19.5%) patients reported treatment-related AEs; 9 (2.8%) patients reported serious AEs. No patients had adrenal insufficiency, treatment-related significant infections or laboratory abnormalities. No deaths were reported.ConclusionIn patients with RA, fosdagrocorat 10 mg and 15 mg demonstrated efficacy similar to prednisone 10 mg and safety similar to prednisone 5 mg.Trial registration numberNCT01393639

At least thirteen parameters relating phenanthrene and methylated phenanthrenes to the maturity of organic matter have been defined in the literature and a mass of the data have been accumulated. However, these parameters are not always effective in many basins. To explore an effective approach for using these big data, this paper re-studies the relationship of methyl- and dimethyl-phenanthrenes to the maturity of organic matter, mainly using partial least square regression (PLSR) and geochemical stabilities of these phenanthrenes. The samples for this study were taken from the shale and mudstone in the Cretaceous Qingshankou Formation in the Songliao Basin, China. It was found that integrated use of methyl- and dimethyl-phenanthrenes can overcome the limitations inherent in using them separately, and thus can enhance the accuracy of maturity calculations. The multivariate regression equation achieved from PLSR utilizes 95% of the variance information contained in the relative abundances of 1-, 2-, 3- and 9-MPs, 1,7- and 2,7-DMPs, and (methyl-phenanthrene [MP]; dimethyl-phenanthrene [DMP]). The coefficients of these phenanthrenes in this equation are consistent with their geochemical stabilities. The square of the correlation coefficient (R2 = .94) of the multivariate regression equation is much higher than those (0.69–0.89) of the univariate regression equations derived from the previously-defined phenanthrene parameters. It is suggested that the multivariate regression approach presented in this paper substitute the previously-defined parameters and the corresponding univariate regression equations when they are not effective.

Screening of high-efficient polycyclic aromatic hydrocarbon (PAH)-degrading bacteria is important due to environmental contamination by PAHs. In this study, sediment contaminated with phenanthrene (Phe), pyrene (Pyr), and fluoranthene (Fluo) was used as a source of bacteria. The ability of these isolated bacteria to convert PAHs into valuable products was determined. Based on a primary screening, 20 bacterial isolates were obtained; however, only three strains showed a good PAH-degrading ability, and were identified as Pseudomonas aeruginosa, Pseudomonas sp., and Ralstonia sp. PAH-degrading genes were detected in all isolates. Notably, all selected strains could degrade PAHs using the ortho or meta cleavage pathways due to the presence of catechol dioxygenase genes. The ability of isolated strains to convert PAHs into polyhydroxyalkanoate (PHA) was also evaluated in both single and mixed cultures. Single cultures of P. aeruginosa PAH-P02 showed 100% degradation of PAHs, with the highest biomass (1.27 ± 0.02 g l−1) and PHA content (38.20 ± 1.92% dry cell weight). However, degradative ability and PHA production were decreased when mixtures of PAHs were used. This study showed that P. aeruginosa, Pseudomonas sp., and Ralstonia sp. were able to degrade PAHs and convert them into medium-chain-length (mcl)-PHA. A high content of 3-hydroxydecanoate (3HD, C10) was observed in this study. The formation of mcl-PHA with high 3HD content from Pyr and Fluo, and the assessment of mixed cultures converting PAHs to mcl-PHA, were novel contributions.

Phenanthrenes, which are polycyclic aromatic hydrocarbons comprising three benzene rings, exhibit a diverse range of functions. These compounds are utilized in the synthesis of resins, plant growth hormones, reducing dyes, tannins and other products. Notably, phenanthrenes possess significant pharmacological properties, including anti-tumor, anti-inflammatory and antioxidant activities, offering broad prospects for development, particularly in the fields of medicine and health. Interestingly, although aristolochic acid (AA) is a potent carcinogen, its lactam analogs can kill cancer cells and exhibit therapeutic effects against cancer. This provides a promising strategy for the toxicity-effect transformation of phenanthrenes. In this paper, we reviewed 137 articles to systematically review the anti-tumor potential and toxic effects of natural phenanthrenes isolated from the 19th century to the present, thus offering references and laying a foundation for their further research, development and utilization.