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Chemosphere Sep 2023Sorption studies involving microplastics (MPs) are essential to understand the mechanisms implicated in contaminant retention. In this research, a complete study of the...
Sorption studies involving microplastics (MPs) are essential to understand the mechanisms implicated in contaminant retention. In this research, a complete study of the sorption behaviour of a hormonal contraceptive -levonorgestrel- in MPs of different composition in two distinct matrices was performed, using high-performance liquid chromatography coupled to a UV detector for the determination of levonorgestrel. Characterization of the studied MPs was achieved by X-ray diffraction, differential scanning calorimetry, and Fourier-transformed infrared spectroscopy. Kinetic and isotherm studies were performed using a batch design under controlled conditions: 500 mg of MPs pellets of 3-5 mm diameter, agitation at 125 rpm, and 30 °C. The comparison of results in ultrapure water and artificial seawater, revealed changes in sorption capacity, and the predominant sorption mechanisms involved. Overall, all studied MPs showed sorption affinity towards levonorgestrel, being low-density polyethylene the one with the highest sorption capacity in ultrapure water and polystyrene in seawater.
Topics: Microplastics; Polystyrenes; Polyethylene; Polypropylenes; Plastics; Levonorgestrel; Water; Water Pollutants, Chemical; Adsorption
PubMed: 37244556
DOI: 10.1016/j.chemosphere.2023.139042 -
Head & Face Medicine Dec 2022To assess the repair method of exposure or fracture of the porous high-density polyethylene ear framework after total auricle reconstruction.
OBJECTIVE
To assess the repair method of exposure or fracture of the porous high-density polyethylene ear framework after total auricle reconstruction.
STUDY DESIGN
A prospective case study.
METHODS
From April 2018 to October 2021, 11 patients with framework exposure or fracture after total auricle reconstruction were admitted to the hospital for repair. In these 11 patients, the repair was performed using (1) a temporal muscle flap combined with free skin graft in 5 patients, (2) a mastoid fascia flap combined with free skin graft in 2 patients, (3) a simple local skin flap in 1 patient, (4) combination of a temporalis muscle flap and a mastoid fascia flap together with free skin graft in 2 patients, and (5) a Su-Por helix material combined with a temporal muscle flap and free skin graft in 1 patient.
RESULTS
After follow-up for 3-36 months, except for one patient in whom local exposure again occurred at the same site, the framework was in a good shape in the other patients, and all the skin graft survived.
CONCLUSION
The defect of the upper part of the auricle can be repaired using a temporal muscle flap combined with temporal muscle fascia and skin graft. The defect of the middle and lower part of the auricle can be repaired using a mastoid fascia flap combined with skin graft. For framework fracture, the damaged site can be first strengthened with another ear material and then combined with the adjacent fascia flap and free skin graft.
Topics: Humans; Polyethylene; Porosity; Plastic Surgery Procedures; Ear, External; Ear Auricle; Treatment Outcome
PubMed: 36522784
DOI: 10.1186/s13005-022-00345-y -
Water Research Mar 2022Exoelectrogenic biofilm and the associated microbial electrochemical processes have recently been intensively studied for water treatment, but their response to and...
Exoelectrogenic biofilm and the associated microbial electrochemical processes have recently been intensively studied for water treatment, but their response to and interaction with polyethylene (PE) microplastics which are widespread in various aquatic environments has never been reported. Here, we investigated how and to what extent PE microplastics would affect the electrochemistry and microbiology of exoelectrogenic biofilm in both microbial fuel cells (MFCs) and microbial electrolysis cells (MECs). When the PE microplastics concentration was increased from 0 to 75 mg/L in the MECs, an apparent decline in the maximum current density (from 1.99 to 0.74 A/m) and abundance of electroactive bacteria (EAB) in the exoelectrogenic biofilm was noticed. While in the MFCs, the current output was not significantly influenced and the abundance of EAB lightly increased at 25 mg/L microplastics. In addition, PE microplastics restrained the viability of the exoelectrogenic biofilms in both systems, leading to a higher system electrode resistance. Moreover, the microbial community richness and the microplastics-related operational taxonomic units decreased with PE microplastics. Furthermore, the electron transfer-related genes (e.g., pilA and mtrC) and cytochrome c concentration decreased after adding microplastics. This study provides the first glimpse into the influence of PE microplastics on the exoelectrogenic biofilm with the potential mechanisms revealed at the gene level, laying a methodological foundation for the future development of efficient water treatment technologies.
Topics: Bioelectric Energy Sources; Biofilms; Electrodes; Microplastics; Plastics; Polyethylene
PubMed: 35030360
DOI: 10.1016/j.watres.2022.118046 -
International Journal of Molecular... Jul 2022Changes in mitochondrial bioenergetics are believed to take place during osteoclastogenesis. This study aims to assess changes in mitochondrial bioenergetics and...
Changes in mitochondrial bioenergetics are believed to take place during osteoclastogenesis. This study aims to assess changes in mitochondrial bioenergetics and reactive oxygen species (ROS) levels during polyethylene (PE)-induced osteoclastogenesis in vitro. For this purpose, RAW264.7 cells were cultured for nine days and allowed to differentiate into osteoclasts in the presence of PE and RANKL. The total TRAP-positive cells, resorption activity, expression of osteoclast marker genes, ROS level, mitochondrial bioenergetics, glycolysis, and substrate utilization were measured. The effect of tocotrienols-rich fraction (TRF) treatment (50 ng/mL) on those parameters during PE-induced osteoclastogenesis was also studied. During PE-induced osteoclastogenesis, as depicted by an increase in TRAP-positive cells and gene expression of osteoclast-related markers, higher proton leak, higher extracellular acidification rate (ECAR), as well as higher levels of ROS and NADPH oxidases (NOXs) were observed in the differentiated cells. The oxidation level of some substrates in the differentiated group was higher than in other groups. TRF treatment significantly reduced the number of TRAP-positive osteoclasts, bone resorption activity, and ROS levels, as well as modulating the gene expression of antioxidant-related genes and mitochondrial function. In conclusion, changes in mitochondrial bioenergetics and substrate utilization were observed during PE-induced osteoclastogenesis, while TRF treatment modulated these changes.
Topics: Cell Differentiation; Energy Metabolism; Mitochondria; Osteoclasts; Osteogenesis; Polyethylene; RANK Ligand; Reactive Oxygen Species
PubMed: 35955464
DOI: 10.3390/ijms23158331 -
Water Research Aug 2021Biofouling causing an increase in plastic density and sinking is one of the hypotheses to account for the unexpectedly low amount of buoyant plastic debris encountered...
Biofouling causing an increase in plastic density and sinking is one of the hypotheses to account for the unexpectedly low amount of buoyant plastic debris encountered at the ocean surface. Field surveys show that polyethylene and polypropylene, the two most abundant buoyant plastics, both occur below the surface and in sediments, and experimental studies confirm that biofouling can cause both of these plastics to sink. However, studies quantifying the actual density of fouled plastics are rare, despite the fact that density will determine the transport and eventual fate of plastic in the ocean. Here we investigated the role of microbial biofilms in sinking of polyethylene microplastic and quantified the density changes natural biofouling communities cause in the coastal waters of the North Sea. Molecular data confirmed the variety of bacteria and eukaryotes (including animals and other multicellular organisms) colonizing the plastic over time. Fouling communities increased the density of plastic and caused sinking, and the plastic remained negatively buoyant even during the winter with lower growth rates. Relative surface area alone, however, did not predict whether a plastic piece sank. Due to patchy colonization, fragmentation of sinking pieces may result in smaller pieces regaining buoyancy and returning to the surface. Our results suggest that primarily multicellular organisms cause sinking of plastic pieces with surface area to volume ratios (SA:V) below 100 (generally pieces above a couple hundred micrometers in size), and that this is a "tipping point" at which microbial biofilms become the key players causing sinking of smaller pieces with higher SA:V ratios, including most fibers that are too small for larger (multicellular) organisms to colonize.
Topics: Animals; Biofouling; Environmental Monitoring; North Sea; Plastics; Polyethylene; Water Pollutants, Chemical
PubMed: 34102596
DOI: 10.1016/j.watres.2021.117289 -
Journal of Hazardous Materials Aug 2021Plastic wastes are becoming the most common form of marine debris and present a growing global pollution problem. Here, we used a screening approach on hundreds of...
Plastic wastes are becoming the most common form of marine debris and present a growing global pollution problem. Here, we used a screening approach on hundreds of plastic waste-associated samples and discovered a marine bacterial community capable of efficiently colonizing and degrading both poly(ethylene terephthalate) (PET) and polyethylene (PE). Using absolute quantitative 16S rRNA sequencing and cultivation methods, we obtained corresponding abundance and purified cultures of three bacterial strains that mediated plastic degradation. We further performed numerous techniques to characterize the efficient degradation of PET and PE by the reconstituted bacterial community containing these three bacteria. Additionally, we used liquid chromatography-mass spectrometry to further demonstrate the degradation of PET and PE films by the reconstituted bacterial community. We conducted transcriptomic methods to investigate the plastic degradation process and potential degradation mechanisms mediated by our reconstituted bacterial community. Lastly, we overexpressed PE degradation enzymes based on transcriptomic results and verified their significant degradation effects on the PE films. Overall, our study establishes a stable marine bacterial community that efficiently degrades PET and PE and provides insights into plastic degradation pathways and their associated biological and mechanistic processes-paving the way for developing microbial products against plastic wastes.
Topics: Bacteria; Biodegradation, Environmental; Ethylenes; Phthalic Acids; Plastics; Polyethylene; Polyethylene Terephthalates; RNA, Ribosomal, 16S
PubMed: 34489083
DOI: 10.1016/j.jhazmat.2021.125928 -
The Science of the Total Environment Jul 2022Microplastics (MPs) are present in all environments, and concerns over their possible detrimental effects on flora and fauna have arisen. Density separation (DS) is...
Microplastics (MPs) are present in all environments, and concerns over their possible detrimental effects on flora and fauna have arisen. Density separation (DS) is commonly used to separate MPs from soils to allow MP quantification; however, it frequently fails to extract high-density MPs sufficiently, resulting in under-estimation of MP abundances. In this proof-of-concept study, a novel three-stage extraction method was developed, involving high-gradient magnetic separation and removal of magnetic soil (Stage 1), magnetic tagging of MPs using surface modified iron nanoparticles (Stage 2), and high-gradient magnetic recovery of surface-modified MPs (Stage 3). The method was optimised for four different soil types (loam, high‑carbon loamy sand, sandy loam and high-clay sandy loam) spiked with different MP types (polyethylene, polyethylene terephthalate, and polytetrafluoroethylene) of different particle sizes (63 μm to 2 mm) as well as polyethylene fibres (2-4 mm). The optimised method achieved average recoveries of 96% for fibres and 92% for particles in loam, 91% for fibres and 87% for particles in high‑carbon loamy sand, 96% for fibres and 89% for particles in sandy loam, and 97% for fibres and 94% for particles in high-clay sandy loam. These were significantly higher than recoveries achieved by DS, particularly for fibres and high-density MPs (p < 0.05). To demonstrate the practical application of the HGMS method, it was applied to a farm soil sample, and high-density MP particles were only recovered by HGMS. Furthermore, this study showed that HGMS can recover fibre-aggregate complexes. This improved extraction method will provide better estimates of MP quantities in future studies focused on monitoring the prevalence of MPs in soils.
Topics: Carbon; Clay; Magnetic Phenomena; Microplastics; Plastics; Polyethylene; Sand; Soil
PubMed: 35364148
DOI: 10.1016/j.scitotenv.2022.154912 -
Hernia : the Journal of Hernias and... Dec 2020In Africa and other Low Resource Settings (LRS), the guideline-based and thus in most cases mesh-based treatment of inguinal hernias is only feasible to a very limited...
INTRODUCTION
In Africa and other Low Resource Settings (LRS), the guideline-based and thus in most cases mesh-based treatment of inguinal hernias is only feasible to a very limited extent. This has led to an increased use of low cost meshes (LCMs, mostly mosquito meshes) for patients in LRS. Most of the LCMs used are made of polyethylene or polyester, which must be sterilized before use. The aim of our investigations was to determine changes in the biocompatibility of fibroblasts as well as mechanical and chemical properties of LCMs after steam sterilization.
MATERIAL AND METHODS
Two large-pored LCMs made of polyester and polyethylene in a size of 11 x 6 cm were cut and steam sterilized at 100, 121 and 134 °C. These probes and non-sterile meshes were then subjected to mechanical tensile tests in vertical and horizontal tension, chemical analyses and biocompatibility tests with human fibroblasts. All meshes were examined by stereomicroscopy, scanning electron microscopy (SEM), LDH (cytotoxicity) measurement, viability testing, pH, lactate and glycolysis determination.
RESULTS
Even macroscopically, polyethylene LCMs showed massive shrinkage after steam sterilization, especially at 121 and 134 °C. While polyester meshes showed no significant changes after sterilization with regard to deformation and damage as well as tensile force and stiffness, only the unsterile polyethylene mesh and the mesh sterilized at 100 °C could be tested mechanically due to the shrinkage of the other specimen. For these meshes the tensile forces were about four times higher than for polyester LCMs. Chemical analysis showed that the typical melting point of polyester LCMs was between 254 and 269 °C. Contrary to the specifications, the polyethylene LCM did not consist of low-density polyethylene, but rather high-density polyethylene and therefore had a melting point of 137 °C, so that the marked shrinkage described above occurred. Stereomicroscopy confirmed the shrinkage of polyethylene LCMs already after sterilization at 100 °C in contrast to polyester LCMs. Surprisingly, cytotoxicity (LDH measurement) was lowest for both non-sterile LCMs, while polyethylene LCMs sterilized at 100 and 121 °C in particular showed a significant increase in cytotoxicity 48 hours after incubation with fibroblasts. Glucose metabolism showed no significant changes between sterile and non-sterile polyethylene and polyester LCMs.
CONCLUSION
The process of steam sterilization significantly alters mechanical and structural properties of synthetic hernia mesh implants. Our findings do not support a use of low-cost meshes because of their unpredictable properties after steam sterilization.
Topics: Female; Humans; Male; Polyethylene; Steam; Sterilization; Surgical Mesh
PubMed: 32975699
DOI: 10.1007/s10029-020-02272-w -
PeerJ 2023This study aimed to examine the systemic effects of contemporary calcium silicate cements (CSC) contain different radiopacifiers in rats.
AIM
This study aimed to examine the systemic effects of contemporary calcium silicate cements (CSC) contain different radiopacifiers in rats.
MATERIALS & METHODS
Polyethylene tubes filled with BIOfactor MTA (BIO), Neo MTA Plus (NEO), MTA Repair HP (REP), Biodentine (DENT) and empty tubes (control group) were implanted into the subcutaneous tissues of 80 male Spraque Dawley rats for 7 and 30 days ( = 8). After 7 and 30 day, samples of liver and kidney tissues were submitted to histopathological analysis. Blood samples were collected to evaluate changes in hepatic and renal functions of rats. Wilcoxon and Dunn Bonferroni tests were used to compare between the 7th and 30th days in order to evaluate the histopathological data. Paired-sample t-test was used to compare laboratory values between the 7th and 30th days, ANOVA analysis and a Tukey test were used to compare values between groups ( < 0.05).
RESULTS
On the 7th day, REP, BIO and NEO groups were statistically similar in kidney tissue and the degree of inflammation was found to be significantly higher in these groups compared to the control and DENT groups. On the 30th day, the degree of inflammation of the REP and NEO groups in the kidney tissue was found to be significantly higher than the control, BIO and DENT groups. Although the inflammation in the liver was moderate and mild on the 7th and 30th days, no statistically significant difference was observed between the groups. Vascular congestion was evaluated as mild and moderate in kidney and liver in all groups, and no statistically significant difference was observed between the groups. While there was no statistically significant difference between the groups in the 7th day AST, ALT and urea values, when the creatinine values were compared, the DENT and NEO groups were found to be statistically similar and significantly lower than the control group. On the 30th day, ALT values were statistically similar between the groups. The AST values of the BIO group were found to be significantly higher than the DENT group. While BIO, DENT, NEO and control groups had statistically similar urea values, the REP group was found to be significantly higher than the other groups. The creatinine value of the REP group was significantly higher than the groups other than the control group ( < 0.05).
CONCLUSION
CSCs with different radiopacifiers had similar and acceptable effects on the histological examination of the kidneys and liver systemically, and serum ALT, AST, urea, creatinine levels.
Topics: Male; Animals; Rats; Creatinine; Inflammation; Polyethylene; Urea
PubMed: 37312877
DOI: 10.7717/peerj.15376 -
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