Investigation on the Thermo-Oxidative Degradation of Polyethylene, Poly(vinyl chloride), and Polystyrene Using NiPIm1.5 and NiPIm2 Nanocomposites
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ABSTRACT:
SUBMITTER: Aravind R
PROVIDER: S-EPMC8582061 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:Microbial fouling is a costly issue, which impacts a wide range of industries, such as healthcare, food processing, and construction industries, and improved strategies to reduce the impact of fouling are urgently required. Slippery liquid-infused porous surfaces (SLIPSs) have recently been developed as a bioinspired approach to prevent antifouling. Here, we report the development of slippery, superhydrophilic surfaces by infusing roughened poly(vinyl chloride) (PVC) substrates with phosphonium ionic liquids (PILs). These surfaces were capable of reducing viable bacterial adherence by Staphylococcus aureus and Pseudomonas aeruginosa by >6 log10 cfu mL-1 after 24 h under static conditions relative to control PVC. Furthermore, we report the potential of a series of asymmetric quaternary alkyl PILs with varying alkyl chain lengths (C4-C18) and counteranions to act as antimicrobial agents against both Gram +ve and Gram -ve bacteria and illustrate their potential as antimicrobial alternatives to traditional fluorinated lubricants commonly used in the synthesis of SLIPSs.
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Project description:Plastic waste is recognised as hazardous, with the risk increasing as the polymers break down in nature to secondary microplastics or even nanoplastics. The number of studies reporting on the prevalence of microplastic in every perceivable niche and bioavailable to biota is dramatically increasing. Knowledge of the ecotoxicology of microplastic is advancing as well; however, information regarding plants, specifically aquatic macrophytes, is still lacking. The present study aimed to gain more information on the ecotoxicological effects of six different polymer types as 4 mm microplastic on the morphology (germination and growth) and the physiology (catalase and glutathione S-transferase activity) of the rooted aquatic macrophyte, Nelumbo nucifera. The role of sediment was also considered by conducting all exposure both in a sediment-containing and sediment-free exposure system. Polyvinyl chloride and polyurethane exposures caused the highest inhibition of germination and growth compared to the control. However, the presence of sediment significantly decreased the adverse effects. Catalase activity was increased with exposure to polyvinyl chloride, polyurethane, and polystyrene, both in the presence and absence of sediment but more so in the sediment-free system. Glutathione S-transferase activity was significantly increased with exposure to polypropylene, polyvinyl chloride, and polyethylene terephthalate in the sediment-free system and exposure to polyethylene terephthalate and polyurethane in the absence of sediment. There was no clear correlation between the morphological and physiological effects observed. Further studies are required to understand the underlying toxicity mechanism of microplastics.
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Project description:A shotgun metagenome microarray was created and used to investigate gene transcription during vinyl chloride (VC) dechlorination by a microbial enrichment culture called KB1. The array was constructed by spotting genomic fragments amplified from short-insert libraries of KB1 metagenomic DNA. Subsequently, the microarrays were interrogated with RNA extracted from KB1 during VC dechlorination (VC+methanol), and in the absence of VC (methanol-only). The most differentially expressed spots, and spots with the highest intensities, were then chosen to be sequenced. Sequencing revealed that Dehalococcoides (Dhc) genes involved in transcription, translation and energy generation were up-regulated during VC degradation. Furthermore, the results indicated that the reductive dehalogenase homologous (RDH) gene KB1rdhA14 is the only RDH gene up-regulated upon VC degradation, and that multiple RDH genes were more highly transcribed in the absence of VC. Numerous hypothetical genes from Dehalococcoides were also more highly transcribed in methanol only treatments and indicate that many uncharacterized proteins are involved in cell maintenance in the absence of chlorinated substrates. Spots with genes from Spirochaetes, Chloroflexi, Geobacter, Methanogens and phage organisms were differentially expressed and sequencing provided information from these uncultivated organisms that can be used to design primers for more targeted studies. This array format is powerful, as it does not require a priori sequence knowledge. This study provides the first report of such arrays being used to investigate transcription in a mixed community, and shows that this array format can be used to screen metagenomic libraries for functionally important genes.
2010-01-27 | GSE20041 | GEO
Project description:Unbleached lignocellulose fibers were studied for the fabrication of wood-based UV-absorbing nanofibers and were used to produce transparent nanocomposites. Groundwood pulp (GWP) and sawdust were selected as raw materials thanks to their low processing degree of fibers and abundant availability as a low-value industrial side stream. Both materials were first sulfated using a reactive deep eutectic solvent. The sulfated wood and sawdust nanofibers (SWNFs and SSDNFs, respectively) were fabricated using a mild mechanical disintegration approach. As a reference material, sulfated cellulose nanofibers (SCNFs) were obtained from bleached cellulose pulp. Our results showed that both GWP and sawdust exhibited similar reactivity compared with bleached cellulose pulp, whereas the yields of sulfated lignin-containing pulps were notably higher. The diameters of both SWNFs and SSDNFs were approximately 3 nm, which was similar to those of the SCNFs. When 10 wt % of lignin-containing nanofibers were mixed together with poly(vinyl alcohol), the fabrication of nanocomposites with only a minimal decrease in transparency in the visible light spectrum was achieved. Transmission in the UV region, on the other hand, was significantly reduced by SWNFs and SSDNFs, whereas SCNFs had only a minor UV-absorbing property. Although the reinforcing effect of lignin-containing nanofibers was lower compared with that of SCNFs, it was comparable with those of other UV-absorbing additives reported in the literature. Overall, the wood-based UV-absorbing nanofibers could have a valuable use in optical applications such as lenses and optoelectronics.
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