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Chemosphere Jul 2023The present study investigated the adsorption mechanism of titanium dioxide nanoparticles (nTiO) on polyethylene microplastics (MPs) and the resulting photocatalytic...
The present study investigated the adsorption mechanism of titanium dioxide nanoparticles (nTiO) on polyethylene microplastics (MPs) and the resulting photocatalytic properties. This effort was supported by ecotoxicological assessments of MPs with adsorbed nTiO on the immobility and behaviour of Daphnia magna in presence and absence of UV irradiation. The results showed that nTiO were rapidly adsorbed on the surface of MPs (72% of nTiO in 9 h). The experimental data fit well with the pseudo-second order kinetic model. Both suspended nTiO and nTiO immobilized on MPs exhibited comparable photocatalytic properties, with the latter showing a lower effect on Daphnia mobility. A likely explanation is that the suspended nTiO acted as a homogeneous catalyst under UV irradiation and generated hydroxyl radicals throughout the test vessel, whereas the nTiO adsorbed on MPs acted as a heterogeneous catalyst and generated hydroxyl radicals only locally and thus near the air-water interface. Consequently, Daphnia, which were hiding at the bottom of the test vessel, actively avoided exposure to hydroxyl radicals. These results suggest that the presence of MPs can modulate the phototoxicity of nTiO - at least the location at which it is active - under the studied conditions.
Topics: Microplastics; Plastics; Polyethylene; Adsorption; Kinetics; Titanium; Nanoparticles; Water Pollutants, Chemical
PubMed: 37030341
DOI: 10.1016/j.chemosphere.2023.138628 -
Hip International : the Journal of... Nov 2022The aim of this prospective, randomised and controlled study was to evaluate the wear and fixation properties of a new cemented highly cross-linked all-polyethylene... (Randomized Controlled Trial)
Randomized Controlled Trial
Evaluation of a new cemented highly cross-linked all-polyethylene cup: a prospective and randomised study assessing wear and fixation characteristics using radiostereometric analysis.
BACKGROUND AND PURPOSE
The aim of this prospective, randomised and controlled study was to evaluate the wear and fixation properties of a new cemented highly cross-linked all-polyethylene (HXLPE) cup in comparison with a conventional cemented ultra-high molecular weight polyethylene (ConvPE) cup using radiostereometric analysis (RSA).
PATIENTS AND METHODS
A total of 58 patients (58 hips) with primary osteoarthritis (OA) were enrolled in a randomised controlled trial to receive either a ConvPE cup (control) or HXLPE cup (intervention) with identical geometry. The subjects were randomised in a 1:1 ratio. The primary endpoint was proximal wear measured as femoral head penetration into the cup, secondary outcomes were 3D-wear and annual proximal wear from 1 to 5 years. Cup fixation was measured as movement of the cup in relation to the acetabular bone with proximal migration being the primary outcome measure, 3D-migration and change in inclination as secondary outcomes. The patients were followed for 5 years with RSA performed postoperatively, at 3, 12, 24, and 60 months.
RESULTS
The HXLPE displayed a lower median proximal femoral head penetration compared to ConvPE, with a median difference at 2 years of -0.07 mm (95% CI, -0.10 to -0.04 mm), and -0.19 mm (95% CI, -0.27 to -0.15 mm) at 5 years. Annual proximal wear between 1 and 5 years was 0.03 mm/year for HXLPE and 0.06 mm/year for ConvPE (mean difference 0.05 mm, [95% CI, 0.03-0.07 mm]). Proximal migration, 3D migration and change in inclination was numerically slightly higher for HXLPE, albeit not statistically significant.
CONCLUSIONS
Compared to ConvPE, the HXLPE cup displayed significantly lower polyethylene wear. Cup migration was not statistically significant different.
CLINICALTRIALS.GOV IDENTIFIER
NCT04322799.
Topics: Humans; Radiostereometric Analysis; Polyethylene; Hip Prosthesis; Arthroplasty, Replacement, Hip; Prospective Studies; Prosthesis Failure; Prosthesis Design
PubMed: 33566703
DOI: 10.1177/1120700021989991 -
Ecotoxicology and Environmental Safety Oct 2022Although microplastics (MPs; <5 mm) may interact with co-contaminants (e.g., petroleum) in marine aquatic systems, little is known about their combined toxicity....
Elucidating the negatively influential and potentially toxic mechanism of single and combined micro-sized polyethylene and petroleum to Chlorella vulgaris at the cellular and molecular levels.
Although microplastics (MPs; <5 mm) may interact with co-contaminants (e.g., petroleum) in marine aquatic systems, little is known about their combined toxicity. Therefore, this study explored the toxicities and their mechanisms of micro-sized polyethylene (mPE) and their combination with petroleum to Chlorella vulgaris. The single MPs at various particle sizes, concentrations, and aging degree, single petroleum, and their combinations, were found to pose toxicities to C. vulgaris. This study also found the microcosm's microbial diversity changed. The microbial communities in the C. vulgaris biotopes were altered under exposure to mPE and petroleum, and were disturbed by external factors such as MPs particle size, concentration, aging time, and the combination with petroleum. Furthermore, as compared with the toxicity of petroleum on microalgal transcriptional function, mPE caused less toxic to C. vulgaris, and only impact the posttranslational modification, protein turnover, and signal transduction processes. Most importantly, mPE reduced petroleum toxicity in C. vulgaris via regulating the ABC transporter, eukaryotic ribosome synthesis, and the citrate cycle metabolic pathways. Overall, our findings could fundamentally provide insights into the joint ecotoxicological effects of MPs and petroleum, and highlight the potential risks of co-exsiting pollutants.
Topics: ATP-Binding Cassette Transporters; Chlorella vulgaris; Citrates; Microplastics; Petroleum; Plastics; Polyethylene; Water Pollutants, Chemical
PubMed: 36152431
DOI: 10.1016/j.ecoenv.2022.114102 -
Journal of Pharmaceutical Sciences Jul 2020Semifluorinated alkanes (SFAs) are aprotic solvents, which may be used as drug solvents for topical ocular applications, for instance, in dry eye syndrome. Their...
Semifluorinated alkanes (SFAs) are aprotic solvents, which may be used as drug solvents for topical ocular applications, for instance, in dry eye syndrome. Their physical properties suggest that they might be prone to interaction with plastic materials, such as, polyethylene (PE) and polypropylene (PP), which are commonly used as packaging materials for pharmaceutical products. In this study, we investigate interactions of PE and PP with a liquid SFA perfluorohexyloctane (PFHO) using differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and cross-polarized light microscopy. Binary phase diagrams of PFHO-PE and PFHO-PP systems demonstrating interactions of PFHO with the polymeric materials were constructed based on DSC data. According to this data, PFHO tends to lower the melting temperatures of PE and PP. The equilibrium values of solubilities of the polymers in PFHO and PFHO in the polymers were obtained by extrapolation of melting enthalpy data. Absorption of PFHO by PE and PP materials at ambient conditions after 4 weeks of equilibration was also studied by TGA. From the presented results, it may be concluded that thorough studies of interactions of PE or PP with SFAs are required when these materials are used as packaging components in SFA-based formulations.
Topics: Fluorocarbons; Pharmaceutical Preparations; Polyethylene; Polypropylenes
PubMed: 32240694
DOI: 10.1016/j.xphs.2020.03.026 -
Scientific Reports Jun 2022250 µm particle size of wood and polyethylene (PE) materials were compounded at mixing proportions of 60/40, 70/30, and 80/20 (with an increase in polymer to decrease...
250 µm particle size of wood and polyethylene (PE) materials were compounded at mixing proportions of 60/40, 70/30, and 80/20 (with an increase in polymer to decrease in wood content) and extruded using a single screw extruder at a temperature range of 110-135 °C. The particles of Gmelina Arborea, Tectona grandis, Cordia milleni, and Nauclea diderichii with recycled Polyethylene were compounded and compressed at 175 N/mm to produce biopolymer composites. The biopolymer composites were subjected to dimensional stability test at 24 h of the water soak method and the ability to withstand load-bearing capacity was investigated. The outcome of the results shows that extruded-compressive biopolymer composites had values ranging from 0.06-1.43 g/cm, 0.38-3.41%, and 0.82-6.85% for observed density, water absorption, and thickness swelling at 24 h of a water soak test. The mechanical properties values ranged from 0.28 Nmm-21.35 Nmm and 0.44-550.06 Nmm for flexural modulus and strength; and 191.43 Nmm-1857.24 Nmm and 0.35 Nmm-243.75 Nmm for tensile modulus and strength respectively. It was observed that moisture uptake and strength displayed by the composites vary accordingly in values obtained for wood species at different mixing proportions. As observed that the more polyethylene content is compounded to wood, the better its dimensional stability, and flexural and tensile properties. The wood particles of Cordia milleni compounded at a proportion of 60 to 40 (polyethylene/wood) performed best in dimensional stability and load-bearing capacity. This study confirmed the effect of methods on wood species and recycled PE for manufacturing wood polymer-based composite for both indoor and outdoor applications.
Topics: Biopolymers; Nigeria; Polyethylene; Polymers; Water; Wood
PubMed: 35732701
DOI: 10.1038/s41598-022-14691-z -
Scientific Reports Sep 2023Microplastic (MP) pollution in agricultural soils, resulting from the use of plastic mulch, compost, and sewage sludge, jeopardizes the soil microbial populations....
Microplastic (MP) pollution in agricultural soils, resulting from the use of plastic mulch, compost, and sewage sludge, jeopardizes the soil microbial populations. However, the effects of MPs on soil chemical properties and microbial communities remain largely unknown. Here, we investigated the effects of different concentration levels (0, 0.1, 1, 3, 5, and 7%; w:w) of low-density polyethylene (LDPE) MPs on the chemical properties and bacterial communities of agricultural soil in an incubation study. The addition of LDPE MPs did not drastically change soil pH (ranging from 8.22 to 8.42). Electrical conductivity increased significantly when the LDPE MP concentrations were between 1 and 7%, whereas the total exchangeable cations (Na, K, Mg, and Ca) decreased significantly at higher LDPE MP concentrations (3-7%). The highest available phosphorus content (2.13 mg kg) was observed in 0.1% LDPE MP. Bacterial richness (Chao1 and Ace indices) was the lowest at 0.1% LDPE MP, and diversity indices (Shannon and Invsimpson) were higher at 0 and 1% LDPE MP than at other concentrations. The effect of LDPE MP concentrations on bacterial phyla remained unchanged, but the bacterial abundance varied. The relative abundance of Proteobacteria (25.8-33.0%) was the highest in all treatments. The abundance of Acidobacteria (15.8-17.2%) was also high, particularly in the 0, 0.1, and 1% LDPE MPs. With the increase in LDPE MP concentration, the abundance of Actinobacteria gradually increased from 7.80 to 31.8%. Our findings suggest that different MP concentration levels considerably alter soil chemical properties and microbial composition, which may potentially change the ecological functions of soil ecosystems.
Topics: Microplastics; Soil; Plastics; Polyethylene; Microbiota; Bacteria
PubMed: 37770500
DOI: 10.1038/s41598-023-42285-w -
PloS One 2021Polyethylene covers are claimed to be useful in preventing ocular surface diseases (OSD); however, evidence of their clinical efficacy is limited. This clinical trial... (Randomized Controlled Trial)
Randomized Controlled Trial
Polyethylene eye-cover versus artificial teardrops in the prevention of ocular surface diseases in comatose patients: A prospective multicenter randomized triple-blinded three-arm clinical trial.
BACKGROUND
Polyethylene covers are claimed to be useful in preventing ocular surface diseases (OSD); however, evidence of their clinical efficacy is limited. This clinical trial aimed to compare the use of polyethylene eye covers and artificial teardrops versus normal saline on the incidence and severity of OSD in comatose patients.
METHODS
Of 90 eligible patients randomly assigned to three treatment groups, 79 patients completed the study, In group A, patients (n = 25) received artificial teardrops for left and normal saline for right eyes, in group B (n = 29) polyethylene covers for left and normal saline for right eyes, and in group C (n = 25) polyethylene covers for left and artificial teardrops for right eyes. As the patients were comatose, their blinding did not applicable, and a blinded observer evaluated the patients' eyes based on the Corneal Fluorescein Staining Pattern. The blinded analyzer analyzed collected data by SPSS-16 software at a 95% confidential level.
RESULTS
The OSDs were observed in 65 (41.14%) out of 158 eyes examined. The artificial teardrop was more effective than the normal saline in group A, polyethylene eye cover was more useful than the normal saline in group B, and polyethylene eye cover was more effective than the artificial teardrop in group C in reducing the incidence of OSD (p< 0.01). Polyethylene eye covers had the most impact on reducing the severity of the OSD compared to the other interventions (p< .001).
CONCLUSIONS
Polyethylene eye covers significantly reduced the incidence and severity of OSD. Using polyethylene cover is suggested as a safe, effective, and accessible eye care intervention for preventing OSD in comatose patients.
TRIAL REGISTRATION
(IRCT201609129014N115), Iranian Registry of Clinical Trials.
Topics: Adult; Aged; Aged, 80 and over; Coma; Double-Blind Method; Dry Eye Syndromes; Female; Humans; Incidence; Male; Middle Aged; Ophthalmic Solutions; Polyethylene; Prospective Studies
PubMed: 33793585
DOI: 10.1371/journal.pone.0248830 -
Scientific Reports Mar 2023Microplastic fragments (microfragments) are among the most abundant microplastic shapes found in marine ecosystems throughout the world. Due to their limited commercial...
Microplastic fragments (microfragments) are among the most abundant microplastic shapes found in marine ecosystems throughout the world. Due to their limited commercial availability, microfragments are rarely used in laboratory experiments. Here a novel method of microfragment production has been developed and validated. Polyethylene and polypropylene plastic stock (2 and 3 mm thick respectively) was ground using a cryomill, washed, and rinsed through a stack of sieves. Microfragments were prepared at three distinct size classes (53-150, 150-300, 300-1000 μm) and were confirmed to be accurate and consistent in size. Employing a novel ice cap dosing technique, microfragments were accurately dosed into experimental vials while excluding headspace, facilitating particle suspension without the aid of chemical surfactants. A proof of principle ingestion experiment confirmed the bioavailability of 53-150 μm polyethylene microfragments to brine shrimp Artemia sp. Together, these methods provide a controlled way to produce and dose microplastic fragments for experimental and analytical research.
Topics: Animals; Plastics; Microplastics; Ecosystem; Polyethylene; Artemia; Biological Assay; Water Pollutants, Chemical; Environmental Monitoring
PubMed: 36997607
DOI: 10.1038/s41598-023-32250-y -
MSystems Apr 2022Polyethylene (PE) is one of the most abundant plastics in the ocean. The development of a biofilm on PE in the ocean has been reported, yet whether some of the...
Polyethylene (PE) is one of the most abundant plastics in the ocean. The development of a biofilm on PE in the ocean has been reported, yet whether some of the biofilm-forming organisms can biodegrade this plastic in the environment remains unknown. Via metagenomics analysis, we taxonomically and functionally analyzed three biofilm communities using low-density polyethylene (LDPE) as their sole carbon source for 2 years. Several of the taxa that increased in relative abundance over time were closely related to known degraders of alkane and other hydrocarbons. Alkane degradation has been proposed to be involved in PE degradation, and most of the organisms increasing in relative abundance over time harbored genes encoding proteins essential in alkane degradation, such as the genes and CYP153, encoding an alkane monooxygenase and a cytochrome P450 alkane hydroxylase, respectively. Weight loss of PE sheets when incubated with these communities and chemical and electron microscopic analyses provided evidence for alteration of the PE surface over time. Taken together, these results provide evidence for the utilization of LDPE-associated compounds by the prokaryotic communities. This report identifies a group of genes potentially involved in the degradation of the LDPE polymeric structure and/or associated plastic additives in the ocean and describes a phylogenetically diverse community of plastic biofilm-dwelling microbes with the potential for utilizing LDPE-associated compounds as carbon and energy source. Low-density polyethylene (LDPE) is one of the most used plastics worldwide, and a large portion of it ends up in the ocean. Very little is known about its fate in the ocean and whether it can be biodegraded by microorganisms. By combining 2-year incubations with metagenomics, respiration measurements, and LDPE surface analysis, we identified bacteria and associated genes and metabolic pathways potentially involved in LDPE biodegradation. After 2 years of incubation, two of the microbial communities exhibited very similar taxonomic compositions mediating changes to the LDPE pieces they were incubated with. We provide evidence that there are plastic-biofilm dwelling bacteria in the ocean that might have the potential to degrade LDPE-associated compounds and that alkane degradation pathways might be involved.
Topics: Polyethylene; Microbial Consortia; Bacteria; Plastics; Oceans and Seas
PubMed: 35229650
DOI: 10.1128/msystems.01415-21 -
Journal of Medical Case Reports Mar 2022There has been increasing recognition of local and systemic adverse events associated with the release of metal ions and nanoparticles from hip arthroplasty components....
BACKGROUND
There has been increasing recognition of local and systemic adverse events associated with the release of metal ions and nanoparticles from hip arthroplasty components. Adverse local tissue reactions to metal ion debris can include periprosthetic solid and cystic masses known as pseudotumors. These masses can result in pain, swelling, extensive destruction to surrounding hip soft-tissues, and compression syndromes on neurovascular, gastrointestinal, and genitourinary structures. As reports of pseudotumors requiring multidisciplinary excision are limited, we present two pseudotumor cases that were excised through a combined approach.
CASE PRESENTATIONS
The first case involves a 60-year-old Caucasian female with a large pseudotumor with intrapelvic and vascular involvement associated with a metal-on-polyethylene total hip arthroplasty, excised with contributions from general surgery, vascular surgery, and orthopedic surgery. Pseudotumor excision was followed by a revision total hip reconstruction in addition to an abductor mechanism reconstruction with tendo-Achilles allograft. The second case is that of a 64-year-old Caucasian female with a pseudotumor in close relationship to the femoral vessels following a metal-on-metal hip resurfacing, excised with a combination of vascular surgery and orthopedic surgery, with subsequent revision total hip reconstruction.
CONCLUSIONS
There remains a lack of literature to support the extensiveness of pseudotumor excision required in complex cases with significant intrapelvic or vascular involvement. Given the potential for significant adverse effects of large masses, the authors' preference is to involve a multidisciplinary team to achieve a more comprehensive excision while minimizing the risk of potential complications.
Topics: Arthroplasty, Replacement, Hip; Female; Hip Prosthesis; Humans; Metals; Middle Aged; Polyethylene
PubMed: 35317840
DOI: 10.1186/s13256-022-03336-4