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Acta Orthopaedica Apr 2015Wear rates of highly crosslinked polyethylene (XLPE) acetabular components have varied considerably between different published studies. This variation is in part due to... (Review)
Review
BACKGROUND AND PURPOSE
Wear rates of highly crosslinked polyethylene (XLPE) acetabular components have varied considerably between different published studies. This variation is in part due to the different techniques used to measure wear and to the errors inherent in measuring the relatively low amounts of wear in XLPE bearings. We undertook a scoping review of studies that have examined the in vivo wear of XLPE acetabular components using the most sensitive method available, radiostereometric analysis (RSA).
METHODS
A systematic search of the PubMed, Scopus, and Cochrane databases was performed to identify published studies in which RSA was used to measure wear of XLPE components in primary total hip arthroplasty (THA).
RESULTS
18 publications examined 12 primary THA cohorts, comprising only 260 THAs at 2-10 years of follow-up. The mean or median proximal wear rate reported ranged from 0.00 to 0.06 mm/year. However, differences in the manner in which wear was determined made it difficult to compare some studies. Furthermore, differences in RSA methodology between studies, such as the use of supine or standing radiographs and the use of beaded or unbeaded reference segments, may limit future meta-analyses examining the effect of patient and implant variables on wear rates.
INTERPRETATION
This scoping review confirmed the low wear rates of XLPE in THA, as measured by RSA. We make recommendations to enhance the standardization of reporting of RSA wear results, which will facilitate early identification of poorly performing implants and enable a better understanding of the effects of surgical and patient factors on wear.
Topics: Acetabulum; Arthroplasty, Replacement, Hip; Hip Prosthesis; Humans; Polyethylene; Prosthesis Failure; Radiostereometric Analysis
PubMed: 25301435
DOI: 10.3109/17453674.2014.972890 -
Chemosphere Oct 2023Bis(2-ethylhexyl) phthalate (DEHP) transfer from a polyvinyl chloride (PVC) sheet to 9 kinds of particles, namely, polyethylene particles (1-10, 45-53, 90-106 μm),...
Bis(2-ethylhexyl) phthalate (DEHP) transfer from a polyvinyl chloride (PVC) sheet to 9 kinds of particles, namely, polyethylene particles (1-10, 45-53, 90-106 μm), soda lime glass particles (1-38, 45-53, 90-106 μm), black forest soil, carbon black, and cotton linter, for the particle weights of 0.3, 1, 3, and 12 mg/cm, were determined for 1, 3, 7, and 14 days using a passive flux sampler (PFS), as well as standard dust. Transfer amounts to small polyethylene particles (1-10 μm), black forest soil, and carbon black were large (8.5, 16, and 48 μg/mg-particle, respectively, for 0.3 mg/cm for 14 days) and were similar to standard house dust (35 μg/mg-particle). On the other hand, transfer amount to large polyethylene particles (0.056-0.12 μg/mg-particle), soda lime glass (0.18-0.31 μg/mg-particle), and cotton linter (0.42-0.78 μg/mg-particle) were much lower. The DEHP transfer amount to the particles was proportional to the surface area of the particles, but not associated with the organic content. The DEHP transfer amount per surface area to small polyethylene particles was larger than that of other particles, suggesting the contribution of absorption into the polyethylene particle. However, for the larger polyethylene particles with different manufacturing process that may have different crystallinity, the contribution of absorption was small. The amount of DEHP transferred to soda lime glass did not differ from 1 to 14 days, suggesting that an adsorption equilibrium was reached after 1 day. The estimated value of particle/gas partition coefficients of DEHP, K, of small polyethylene, black forest soil and carbon black were much higher (3.6, 7.1, and 18 m/mg, respectively) than those of large polyethylene and soda lime glass particles (0.028-0.11 m/mg).
Topics: Diethylhexyl Phthalate; Polyvinyl Chloride; Soot; Phthalic Acids; Dust; Polyethylene
PubMed: 37433409
DOI: 10.1016/j.chemosphere.2023.139438 -
STAR Protocols Dec 2023Depolymerization and upcycling are promising approaches to managing plastic waste. However, quantitative measurements of reaction rates and analyses of complex product...
Depolymerization and upcycling are promising approaches to managing plastic waste. However, quantitative measurements of reaction rates and analyses of complex product mixtures arising from depolymerization of polyolefins constitute significant challenges in this emerging field. Here, we detail techniques for recovery and analysis of products arising from batch depolymerization of polyethylene. We also describe quantitative analyses of reaction rates and products selectivity. This protocol can be extended to depolymerization of other plastics and characterization of other product mixtures including long-chain olefins. For complete details on the use and execution of this protocol, please refer to Sun et al..
Topics: Polyethylene; Alkenes
PubMed: 37729056
DOI: 10.1016/j.xpro.2023.102575 -
Environmental Science and Pollution... Dec 2023The water quality implications of transferring stormwater through pipes composed of concrete (new and used), polyvinyl chloride (PVC), galvanized corrugated steel (GCS),... (Review)
Review
The water quality implications of transferring stormwater through pipes composed of concrete (new and used), polyvinyl chloride (PVC), galvanized corrugated steel (GCS), high-density polyethylene (HDPE), and pipes subjected to cured in place pipe (CIPP) and spray in place pipe (SIPP) trenchless repair technologies on stormwater quality are reviewed. Studies involve either the use of flowing water or an immersion experimental design, with data showing contact with pipe materials can affect stormwater quality parameters including pH, electrical conductivity (EC), and concentrations of minerals, metals, and organic constituents, e.g. styrene. 'In-transport' changes in pH (1-3 units), EC (2-3-fold), bicarbonate (3-44-fold), and calcium (2-17-fold) in stormwaters were reported following exposure to concrete pipes. Differences between the use of synthetic and field-collected stormwater were identified, e.g. turbidity levels in field-collected stormwater reduced on passage through all pipe types, compared to synthetic water where levels of turbidity on exposure to concrete and cement-based SIPP increased slightly. Transfer through PVC and HDPE pipes had minimal effects on physicochemical parameters, whereas exposure to galvanized corrugated steel pipes led to increases in EC, Zn, and Pb. Though limited data was available, the use of CIPP repairs and associated waste condensate generated during thermal curing and/or incomplete curing of resins was identified to release organic contaminants of concerns (e.g. styrene, vinylic monomers, dibutyl phthalate (DBP), diethyl phthalate (DEP), and benzaldehyde). The implications of findings for both future research and stakeholders with responsibility for reducing diffuse pollution loads to receiving waters are considered.
Topics: Polyethylene; Water Quality; Styrene; Dibutyl Phthalate; Steel
PubMed: 37924396
DOI: 10.1007/s11356-023-30508-6 -
Environment International Mar 2024Microplastics (MPs) are inevitably oxidized in the environment, and their potential toxicity to organisms has attracted wide attention. However, the neurotoxicity and...
Microplastics (MPs) are inevitably oxidized in the environment, and their potential toxicity to organisms has attracted wide attention. However, the neurotoxicity and mechanism of oxidized polyethylene (Ox-PE) MPs to organisms remain unclear. Herein, we prepared oxidized low-density polyethylene (Ox-LDPE) and established a model of MPs exposure by continuously orally gavage of C57BL/6 J mice with LDPE-MPs/Ox-LDPE-MPs for 28 days with or without oral administration of Lactobacillus plantarum DP189 and galactooligosaccharides (DP189&GOS). The experimental results indicated that LDPE-MPs or Ox-LDPE-MPs caused several adverse effects in mice, mainly manifested by behavioral changes, disruption of the intestinal and blood-brain barrier (BBB), and simultaneous oxidative stress, inflammatory reactions, and pathological damage in the brain and intestines. Brain transcriptomic analysis revealed that the cholinergic synaptic signaling pathways, which affect cognitive function, were significantly disrupted after exposure to LDPE-MPs or Ox-LDPE-MPs. Real-time quantitative polymerase chain reaction and Western Blotting results further demonstrated that the critical genes (Slc5a7, Chat and Slc18a3) and proteins (Chat and Slc18a3) in the cholinergic synaptic signaling pathway were significantly down-regulated after exposure to LDPE-MPs or Ox-LDPE-MPs. These alterations lead to reduced acetylcholine concentration, which causes cognitive dysfunction in mice. Importantly, the DP189&GOS interventions effectively mitigated the MPs-induced cognitive dysfunction and intestinal microbiota alteration, improved intestinal and BBB integrity, attenuated the oxidative stress and inflammatory response, and also saw a rebound in the release of acetylcholine. These results indicated that LDPE-MPs and Ox-LDPE-MPs exert neurotoxic effects on mice by inducing oxidative stress, inflammatory responses, and dysregulation of cholinergic signaling pathways in the mouse brain. That probiotic supplementation is effective in attenuating MPs-induced neurotoxicity in mice. Overall, this study reveals the potential mechanisms of neurotoxicity of LDPE-MPs and Ox-LDPE-MPs on mice and their improvement measures, necessary to assess the potential risks of plastic contaminants to human health.
Topics: Humans; Animals; Mice; Polyethylene; Mice, Inbred C57BL; Microplastics; Plastics; Brain-Gut Axis; Acetylcholine; Cholinergic Agents
PubMed: 38484610
DOI: 10.1016/j.envint.2024.108523 -
BMC Biotechnology Jul 2023Plastic pollution is a major global concern to the health and wellbeing of all terrestrial and marine life. However, no sustainable method for waste management is...
Plastic pollution is a major global concern to the health and wellbeing of all terrestrial and marine life. However, no sustainable method for waste management is currently viable. This study addresses the optimisation of microbial enzymatic polyethylene oxidation through rational engineering of laccases with carbohydrate-binding module (CBM) domains. An explorative bioinformatic approach was taken for high-throughput screening of candidate laccases and CBM domains, representing an exemplar workflow for future engineering research. Molecular docking simulated polyethylene binding whilst a deep-learning algorithm predicted catalytic activity. Protein properties were examined to interpret the mechanisms behind laccase-polyethylene binding. The incorporation of flexible GGGGS(x3) hinges were found to improve putative polyethylene binding of laccases. Whilst CBM1 family domains were predicted to bind polyethylene, they were suggested to detriment laccase-polyethylene associations. In contrast, CBM2 domains reported improved polyethylene binding and may thus optimise laccase oxidation. Interactions between CBM domains, linkers, and polyethylene hydrocarbons were heavily reliant on hydrophobicity. Preliminary polyethylene oxidation is considered a necessity for consequent microbial uptake and assimilation. However, slow oxidation and depolymerisation rates inhibit the large-scale industrial implementation of bioremediation within waste management systems. The optimised polyethylene oxidation of CBM2-engineered laccases represents a significant advancement towards a sustainable method of complete plastic breakdown. Results of this study offer a rapid, accessible workflow for further research into exoenzyme optimisation whilst elucidating mechanisms behind the laccase-polyethylene interaction.
Topics: Laccase; Polyethylene; Molecular Docking Simulation; Oxidation-Reduction; Carbohydrates
PubMed: 37415113
DOI: 10.1186/s12896-023-00787-5 -
Knee Surgery, Sports Traumatology,... Oct 2021The Oxford unicompartmental knee replacement (UKR) has a fully congruent mobile bearing to minimise wear. However, with younger higher demand patients, wear remains a...
PURPOSE
The Oxford unicompartmental knee replacement (UKR) has a fully congruent mobile bearing to minimise wear. However, with younger higher demand patients, wear remains a concern. The aim of this study was to quantify the wear rate of Phase 3 Oxford UKR bearings over the course of 5 years and to identify the factors that influence it.
METHODS
40 medial Oxford UKRs recruited for a randomised study of cemented and cementless fixation were studied with Radiostereometric analysis (RSA) at 1 week, 3 months, 6 months, 1 year, 2 years, and 5 years post-operatively and bearing thickness was calculated. Penetration, defined as the change in thickness compared to the 1-week measurement, was determined. Creep (early penetration) and wear (late penetration at a constant rate) were calculated. The influence of demographic factors, Oxford Knee Score (OKS), Tegner score, fixation and bearing overhang (determined by RSA) on wear was analysed.
RESULTS
After 6 months the penetration rate was constant, indicating that wear alone was occurring. The wear rate was 0.07 mm/year (SD 0.03). The creep was 0.06 mm with about 95% occurring during the first 3 months. There was no significant relationship between fixation (cemented/cementless), age, component size, OKS and Tegner score with wear rate. Increasing BMI was associated with decreasing wear (p = 0.042). 37/40 bearings overhung the tibia to some extent and 23/40 overhung the tibia medially. An increase in the area of overhang (p = 0.036), amount of medial overhang (p = 0.028) and distance between the bearing and tibial wall (p = 0.019) were associated with increased wear. Bearings that did not overhang (0.06 mm/year) had less wear (p = 0.025) than those that did (0.08 mm/year). There was no relationship (p = 0.6) between the femoral contact area and wear.
CONCLUSION
During the first three to six months after implantation, the bearing becomes 0.06 mm thinner due to creep. The combined wear rate of the upper and lower surfaces of the bearing is constant (0.07 mm/year). The wear is lower if the bearing does not overhang the tibia so surgeons should aim for the bearing to be close to the tibial wall. The orientation of the femoral component does not influence wear.
LEVEL OF EVIDENCE
Retrospective Study, Level III.
Topics: Arthroplasty, Replacement, Knee; Humans; Knee Prosthesis; Osteoarthritis, Knee; Polyethylene; Prosthesis Design; Retrospective Studies
PubMed: 32940731
DOI: 10.1007/s00167-020-06243-7 -
Scientific Reports Jun 2023A variety of biosensors have been proposed to quickly detect and measure the properties of individual microorganisms among heterogeneous populations, but challenges...
A variety of biosensors have been proposed to quickly detect and measure the properties of individual microorganisms among heterogeneous populations, but challenges related to cost, portability, stability, sensitivity, and power consumption limit their applicability. This study proposes a portable microfluidic device based on impedance flow-cytometry and electrical impedance spectroscopy that can detect and quantify the size of microparticles larger than 45 µm, such as algae and microplastics. The system is low cost ($300), portable (5 cm [Formula: see text] 5 cm), low-power (1.2 W), and easily fabricated utilizing a 3D-printer and industrial printed circuit board technology. The main novelty we demonstrate is the use of square wave excitation signal for impedance measurements with quadrature phase-sensitive detectors. A linked algorithm removes the errors associated to higher order harmonics. After validating the performance of the device for complex impedance models, we used it to detect and differentiate between polyethylene microbeads of sizes between 63 and 83 µm, and buccal cells between 45 and 70 µm. A precision of 3% is reported for the measured impedance and a minimum size of 45 µm is reported for the particle characterization.
Topics: Electric Impedance; Mouth Mucosa; Plastics; Microspheres; Polyethylene
PubMed: 37386229
DOI: 10.1038/s41598-023-37506-1 -
Microbiological Research Feb 2023Microorganisms degrade microplastics, but their potential is still not fully exploited, e.g., due to inadequate selection of microorganisms. We developed an effective...
Microorganisms degrade microplastics, but their potential is still not fully exploited, e.g., due to inadequate selection of microorganisms. We developed an effective selection method of microorganisms capable of polyethylene (PE) and polypropylene (PP) degradation and assessed the scale of polymer degradation by microbial populations. We isolated seven bacterial strains (three Priestia megaterium strains, Klebsiella pneumoniae, Pseudomonas fluorescens, Enterobacter ludwigii, Chryseobacterium sp.) and seven fungal strains (four Fusarium spp., two Lecanicillium spp. and Trichoderma sp.) with PE degradation potential, as well as seven bacterial strains (five Serratia marcescens and two Enterobacter spp.) and six fungal strains (four Aspergillus spp., Fusarium oxysporum and Penicillium granulatum) with PP degradation ability. Scanning electron microscopy (SEM) analysis confirmed the presence of a biofilm and revealed surface changes in both PE and PP pellets, but the greatest changes (microcracks and corrugations) were observed for PP incubated with bacteria. Fourier transform infrared (FTIR) spectroscopy confirmed the structural changes on the studied polymer surfaces. In conclusion, the isolation of plastic-degrading bacteria and fungi from waste landfills represents an effective strategy for the collection of microorganisms with high potential for PE and PP degradation. The bacteria and fungi revealed better potential for PP degradation and PE degradation, respectively.
Topics: Polyethylene; Polypropylenes; Plastics; Biodegradation, Environmental; Fungi
PubMed: 36423546
DOI: 10.1016/j.micres.2022.127251 -
International Orthopaedics Aug 2022This study aimed to evaluate polyethylene (PE) damage and wear lesions to the chamfer of mobile components under mobile and fixed femoral neck impingement at the third...
PURPOSE
This study aimed to evaluate polyethylene (PE) damage and wear lesions to the chamfer of mobile components under mobile and fixed femoral neck impingement at the third articulation, and to determine which femoral neck characteristics should be considered with a dual mobility cup to limit those lesions.
METHODS
Two femoral neck geometries (cylindrical and quadrangular) with two surface finishing roughness (rough and polished), and two head-to-neck ratios (28- and 22.2-mm diameter femoral heads) were evaluated in a hip simulator testing. For each characteristic, six femoral necks were tested with six dual mobility cups under fixed and mobile femoral neck impingement conditions. Chamfer PE damage and volumetric wear were evaluated and compared for each femoral neck characteristic and impingement condition.
RESULTS
Under mobile impingement condition, femoral neck characteristics did not significantly affect PE damage and wear lesions to the chamfer (p = 0.283 to 0.810). However, under fixed impingement condition, significantly higher PE damage and wear lesions to the chamfer were produced by the quadrangular geometry compared to the cylindrical geometry (p = 0.004 to 0.025). In addition, with the quadrangular geometry, rough surface finishing was demonstrated to increase volumetric wear of the chamfer (p = 0.009). No significant influence of head-to-neck ratio was observed on PE damage and wear lesions to the chamfer (p = 0.244 to 0.714).
DISCUSSION
This biomechanical study emphasized that femoral neck characteristics are critical with dual mobility cup and tend to favor a cylindrical geometry particularly whether fixed impingement at the third articulation occurs.
Topics: Arthroplasty, Replacement, Hip; Femur Neck; Hip Prosthesis; Humans; Polyethylene; Prosthesis Design; Prosthesis Failure
PubMed: 35570206
DOI: 10.1007/s00264-022-05415-z