Microplastics in maternal amniotic fluid and their associations with gestational age.

Microplastics (MPs) pollution is a growing global concern due to its potential threat to human health, particularly concerning fetal health. Nevertheless, few studies have examined the sources of fetal MPs exposure and its impact on fetal development. In this study, MPs levels in maternal amniotic fluid (AF) and their associations with measures of fetal growth were investigated. Specifically, 40 human AF samples were collected to determine the presence and characteristics of MPs using laser direct infrared (LD-IR) spectroscopy. MPs were found in 32 out of 40 AF samples, with an average abundance of 2.01 ± 4.19 particles/g. Polyethylene (PE, 38.80 %) and chlorinated polyethylene (CPE, 26.98 %) were the most prevalent polymers. The majority of MPs (87.56 %) were 20-100 µm in size, and fragments (71.23 %) evidently prevailed in morphology. Additionally, a questionnaire was designed to explore the associations between MPs levels in the AF and maternal dietary habits, aiming at unveiling the potential sources of MPs in AF. The MPs levels in the AF were positively associated with the frequency of seafood consumption (r = 0.781, P < 0.001) and bottled water intake (r = 0.386, P = 0.014). Moreover, the associations between MPs levels in maternal AF and measures of fetal growth were evaluated. The abundance of total MPs in maternal AF were significantly negatively associated with gestational age (ß = -0.44, 95 % CI, -0.83, -0.05). This study confirms the presence of MPs in human AF and provides compelling evidence linking them to gestational age, while highlighting the potential risks associated with dietary habits. These findings underscore the need for further investigation into the mechanisms of MPs transmission from mother to fetus and the potential health implications during fetal development, offering valuable insights for future policies aimed at safeguarding maternal and fetal health.

Detection and quantification of microplastic pollution in the endangered Galapagos sea lion.

Marine debris pollution poses a significant global threat to biodiversity, with plastics being the primary debris type found in oceans due to their low-cost production and high demand worldwide. Microplastics (MPs, <5 mm in size) are highly bioavailable to a wide range of marine taxa, including marine mammals, through direct and indirect ingestion routes (i.e., trophic transfer). Recently, MP pollution has been detected on the Galapagos Marine Reserve, so in this study we developed a baseline framework for MP pollution in the Galapagos sea lion (GSL, Zalophus wollebaeki) through scat-based analysis. We collected 180 GSL scat samples from the southeast region following strict quality assurance/quality control protocols to detect, quantify and characterize physical-chemical properties of MPs through visual observations and µFT-IR spectroscopy. We recovered 81 MPs of varying sizes and colors in 37 % of samples (n = 66/180), consisting mostly of fibers (69 %, x¯ = 0.31 ± 0.57 particles scat-1). The number of particles per gram of sample wet weight ranged from 0.02 to 0.22 (x¯ = 0.04 ± 0.05 particles scat wet g-1). El Malecón and Punta Pitt rookeries at San Cristobal Island had the highest number of MPs (x¯ = 0.67 ± 0.51 and 0.43 ± 0.41 particles scat-1, respectively), and blue-colored particles were the most common in all samples. We identified eleven polymers in 46 particles, consisting mostly of polypropylene-polyethylene copolymer, polypropylene, cellulose, polyethylene, and polyvinyl chloride. The textile, fishing, and packaging industries are likely significant sources of microfibers into this insular ecosystem. Our results suggest that the GSL is exposed to MPs due to anthropogenic contamination that is subsequently transferred through trophic processes. These findings provide an important baseline framework and insights for future research on MP pollution in the region, as well as for management actions that will contribute to the long-term conservation of the GSL.

Quantification of microplastic by particle size down to 1.1 µm in surface road dust in an urban city, Japan.

The impact of microplastics (MPs, plastic particles ≤5 mm) on ecosystems is of great concern. Road surfaces represent a significant source of MPs where plastic fragments are physically and chemically reduced to MPs. However, the literature lacks information on fragmentation tendencies below 11 µm. This study aimed to characterize the occurrence of MPs in road dust in different size fractions down to 1.1 µm. Road dust was collected at five sites near a major road in Kusatsu city, Japan, and partitioned by size into 13 fractions (1.1-850 µm). The coarser fractions accounted for a greater proportion of the dust. The percentage of organic matter, determined by loss on ignition, increased as the fractions became finer. Pyrolysis-gas chromatography-mass spectrometry was used to quantify 12 types of polymers in each fraction. The dust was found to contain nine types of MP, namely, polyethylene (PE), polypropylene (PP), polyvinylchloride (PVC), polystyrene (PS), styrene/butadiene rubber (SBR), acrylonitrile/butadiene/styrene resin (ABS), polycarbonate (PC), polymethylmethacrylate (PMMA), and polyamide 66 (PA66). The total MP concentration in road dust particles by particle size fraction (concentrationf) began to increase from the 125-250 µm fraction and remained elevated in finer fractions down to 1.1 µm, indicating that MPs in the road dust micronized to at least 1.1 µm. However, for individual polymer types, the tendency for concentrationf to increase or decrease with particle size fraction varied: the concentrationf of some polymers, such as PE and PVC, remained elevated in fractions down to 1.1 µm; the concentrationf of SBR, a rubber-MP, showed a stable or decreasing trend in fractions of 7.0-11 µm and finer. Particles of PE, PVC, and some other plastics might become increasingly finer, even down to 1.1 µm. Further research is needed to understand the comminution limits of these polymers under pertinent environmental conditions.

Emissions of Formamide and Ammonia from Foam Mats: Online Measurement Based on Dopant-Assisted Photoionization TOFMS and Assessment of Their Exposure for Children.

Formamide has been classified as a Class 1B reproductive toxicant to children by the European Union (EU) Chemicals Agency. Foam mats are a potential source of formamide and ammonia. Online dopant-assisted atmospheric pressure photoionization time-of-flight mass spectrometry (DA-APPI-TOFMS) coupled with a Teflon environmental chamber was developed to assess the exposure risk of formamide and ammonia from foam mats to children. High levels of formamide (average 3363.72 mg/m3) and ammonia (average 1586.78 mg/m3) emissions were measured from 21 foam mats with three different raw material types: ethylene-vinyl acetate (EVA: n = 7), polyethylene (PE: n = 7), and cross-linked polyethylene (XPE: n = 7). The 28 day emission testing for the selected PE mat showed that the emissions of formamide were 2 orders of magnitude higher than the EU emission limit of 20 µg/m3, and formamide may be a permanent indoor contaminant for foam mat products during their life cycle. The exposure assessment of children aged 0.5-6 years showed that the exposure dose was approximately hundreds of mg/kg-day, and the age group of 0.5-2 years was subject to much higher dermal exposures than others. Thus, this study provided key relevant information for further studies on assessing children's exposure to indoor air pollution from foam mats.

Valorisation of fruit peel bioactive into green synthesized silver nanoparticles to modify cellulose wrapper for shelf-life extension of packaged bread.

Fruit peels are rich source of bioactive compounds such as polyphenols, flavonoids, and antioxidants but are often discarded as waste due to limited pharmaceutical and nutraceutical applications. This study aimed to valorise pomegranate and citrus fruit peel into green synthesised silver nanoparticles (AgNPs) in order to modify cellulose-based wrapping material for prospective food packaging applications and propose an alternate and sustainable approach to replace polyethene based food packaging material. Four different concentrations of AgNO3 (0.5 mM, 1 mM, 2 mM, and 3 mM) were used for green synthesis of AgNPs from fruit peel bioactive, which were characterised followed by phytochemical analysis. Ultraviolet-Visible spectroscopy showed surface plasmon resonance at 420 nm, XRD analysis showed 2θ peak at 27.8°, 32.16°, 38.5°, 44.31°, 46.09°, 54.76°, 57.47°, 64.61° and 77.50° corresponding to (210), (122), (111), (200), (231), (142), (241), (220) and (311) plane of face centred cubic crystal structure of AgNPs. Fourier-transform infrared spectroscopy analysis of AgNPs green synthesised from pomegranate and kinnow peel extract showed a major peak at 3277, 1640 and 1250-1020 1/cm while a small peak at 2786 1/cm was observed in case of pomegranate peel extract which was negligible in AgNPs synthesized from kinnow peel extract. Particle sizes of AgNPs showed no statistically significant variance with p > 0.10 and thus, 2 mM was chosen for further experimentation and modification of cellulose based packaging material as it showed smallest average particle size. Zeta potential was observed to be nearly neutral with a partial negative strength due to presence of various phenolic compounds such as presence of gallic acid which was confirmed by ultrahigh performance liquid chromatography-photodiode array(UHPLC-PDA) detector. Thermal stability analysis of green synthesised AgNPs qualified the sterilisation conditions up to 100 °C. AgNPs green synthesized from both the peel extracts had higher polyphenolic content, antioxidant and radical scavenging activity as compared to peel extracts without treatment (p < 0.05). The cellulose based food grade packaging material was enrobed by green synthesised AgNPs. The characterisation of modified cellulose wrappers showed no significant difference in thickness of modified cellulose wrappers as compared with untreated cellulose wrapper (p > 0.42) while weight and grammage increased significantly in modified cellulose wrapper (p < 0.05). The colour values on CIE scale (L*, a* and b*) showed statistically significant increase in yellow and green colour (p < 0.05) for modified cellulose wrappers as compared to control wrapper. The oxygen permeability coefficient, water vapour permeability coefficient, water absorption capacity and water behaviour characteristics (water content, swelling degree and solubility) showed significant decrease (p < 0.05) for modified cellulose wrapper as compared to control wrapper. A uniform distribution and density of green synthesised AgNPs across cellulose wrapper matrix was observed through scanning electron microscopy (SEM) images with no significant aggregation, confirming successful enrobing and stable immobilisation of nanoparticles from cellulose matrix. A seven-day storage study of bread wrapped in modified and control cellulose wrappers showed delayed occurrence of microbial, yeast and mould count in bread packaged in modified cellulose wrappers and thus, resulting in shelf life extension of bread. The results are encouraging for the potential applications of modified cellulose wrappers to replace polyethene based food packaging.

Examination of Microcystin Adsorption by the Type of Plastic Materials Used during the Procedure of Microcystin Analysis.

The incidence of eutrophication is increasing due to fertilizer abuse and global warming. Eutrophication can induce the proliferation of cyanobacteria such as Microcystis, which produces microcystins. Microcystins are toxic to specific organs such as the liver and the heart. Thus, monitoring of microcystins is strongly required to control drinking water and agricultural product qualities. However, microcystins could be adsorbed by plastic materials during sample storage and preparation, hindering accurate analysis. Therefore, the current study examined the recovery rate of microcystins from six plastics used for containers and eight plastics used for membrane filters. Among the six plastics used for containers, polyethylene terephthalate showed the best recovery rate (≥81.3%) for 48 h. However, polypropylene, polystyrene, and high- and low-density polyethylenes showed significant adsorption after exposure for 1 hr. For membrane materials, regenerated cellulose (≥99.3%) showed the highest recovery rate of microcystins, followed by polyvinylidene fluoride (≥94.1%) and polytetrafluoroethylene (≥95.7%). The adsorption of microcystins appeared to be strongly influenced by various molecular interactions, including hydrophobic interaction, hydrogen bonding, and electrostatic interaction. In addition, microcystins' functional residues seemed to be critical factors affecting their adsorption by plastic materials. The present study demonstrates that polyethylene terephthalate and regenerated cellulose membrane are suitable plastic materials for the analysis of microcystins.

Understanding the volatile organic compounds of 1-methylcyclopropylene fumigation and packaging on yellow-fleshed peach via headspace-gas chromatography-ion mobility spectrometry and chemometric analyses.

Headspace-gas chromatography-ion mobility spectrometry (HS-GC-IMS) and chemometric methods were utilized to analyze changes in volatile organic compounds (VOCs) of yellow-fleshed peach by 1-methylcyclopropylene (1-MCP) treatment and modified atmosphere packaging (MAP). Meanwhile, the storage quality of yellow-fleshed peach at room temperature (25°C) was also studied. Yellow-fleshed peach was treated by four methods, namely, nanomaterial packaging (NA), 1-MCP fumigation and nanomaterial packaging (1-MCP-NA), polyethylene (PE) packaging, and 1-MCP fumigation with polyethylene packaging (1-MCP-PE). Changes in the decay rate, firmness, browning index, soluble solid content, and titratable acid of the fruit were then measured at room temperature at 1, 4 and 10 days of storage. Thirty-two VOCs, including terpenoids, alcohols, esters, aldehydes, and ketones, were identified. Seventeen VOCs were found to be significant with predictive variable important in the projection (VIP) > 1 and p < 0.05 by analysis of variance and orthogonal projection to latent structure discriminant analysis (OPLS-DA). After 10 days of storage, the browning index of 1-MCP-NA group was 51.7%, which was lower than the control fruit (PE, 76.7%). Compared with other three treatments, 1-MCP-NA showed the better ability to delay and inhibit decreases in ester and aldehyde contents, and the ethanol content was lowest in the samples treated by 1-MCP-NA during storage. Differences among treatment groups were distinguished by principal component analysis (PCA) and hierarchical clustering heat map. The results showed that 1-MCP-NA could well maintain the quality and flavor stability of yellow-fleshed peach, and it had a good application prospect in the postharvest preservation of yellow-fleshed peach. PRACTICAL APPLICATION: In this study, 1-methylcyclopropylene (1-MCP) combined with nanomaterial (NA) packaging (1-MCP-NA) proved to have a better fresh preservation effect. 1-MCP-NA showed better ability to delay and inhibit decreases in ester and aldehyde contents by HS-GC-IMS technique. It provided a new strategy for postharvest storage of yellow-fleshed peaches.

Occurrence and characteristics of atmospheric microplastics in Mexico City.

While atmospheric microplastics have attracted scientific attention as a significant source of microplastic contamination in the environment, studies in large population centers remain sparse. Here we present the first report on the occurrence and distribution of atmospheric microplastics in Mexico City (Latin America's second most densely populated city), collected using PM10 and PM2.5 active samplers at seven monitoring stations (urban, residential, and industrial) during the dry and wet seasons of 2020. The results showed that microplastics were detected in all of the samples examined, with mean microplastic concentrations (items m-3) of 0.205 ± 0.061 and 0.110 ± 0.055 in PM10 and PM2.5, respectively. The spatial distribution of microplastics showed seasonal variation, with greater abundances in locations closer to industrial and urban centers. There was also a significant difference in microplastic concentrations in PM10 and PM2.5 between the dry and wet seasons. The mean PM2.5/PM10 ratio was 0.576, implying that microplastics were partitioned more towards PM2.5 than PM10 in Mexico City. Fibers were the most prominent shape (>75 %), and blue was the most common color (>60 %). The size characteristics indicated microplastics of varying lengths, ranging from 39 to 5000 µm, with 66 % being <500 µm. Metal contaminants such as aluminum, iron, and titanium were detected using SEM-EDX on randomly selected microplastics. The microplastics were identified as cellophane, polyethylene, polyethylene terephthalate, polyamide, and cellulose (rayon) using ATR-FTIR spectral analysis. Our findings unravel the extent and characteristics of atmospheric microplastics in the Mexico City metropolitan area, which will aid future research to better understand their fate, transport, and potential health risks, demanding more investigations and close monitoring.

Occurrence, distribution, and associated pollutants of plastic pellets (nurdles) in coastal areas of South Texas.

Nurdles, also known as plastic resin pellets, are now a major source of plastic pollution on beaches globally, thus it is important to elucidate their weathering patterns and environmental fates as well as the associated pollutants. In this study we collected nurdles from 24 sites in the coastal bend region of south Texas, covering areas from the near shore railway stations to the adjacent bays and barrier islands. The morphologies of nurdles and associated pollutants including polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), and mercury, were investigated. The results showed that the nurdles varied greatly in color, shape, polymer composition, and oxidation degree. More than 80 % of the nurdles were made with polyethylene, and the rest with polypropylene, polyester, polystyrene, polyethylene-vinyl acetate, and polyvinyl chloride based on Fourier Transform Infrared Spectroscopy (FTIR) analysis. PCBs were not detected on nurdles. PAHs and mercury on nurdles were detected at 12 % and 20 % of the sampling sites. The total concentrations of detectable PAHs ranged from 92.59 to 1787.23 ng/g-nurdle, and the detectable mercury concentrations ranged from 1.23 to 22.25 ng/g-nurdle. Although the concentrations of these pollutants were not at the acute toxic effect level, the presence of PAHs and mercury suggested the potential risk of pollutant exposure to marine organisms in ecosystems, given the fact that nurdles are persistent in the environment.

Effective removal of polymer quaternary ammonium salt by biodegradation and a subsequent Fenton oxidation process.

In this paper, a process combining biodegradation and Fenton oxidation was proposed for the removal of polydiallyldimethylammonium chloride-acrylic-acrylamide-hydroxyethyl acrylate (PDM) in aqueous phase. Biodegradation of PDM was investigated in activated sludge systems, and the effects of the solution pH, mixed liquid suspended solids (MLSS), salinity, co-substrate, and initial substrate concentration, were studied. The biodegradation process was well-described with the Monod model and the values of the kinetics parameters vmax, ks were 0.05 h-1 and 333 mg/L. The optimal biodegradation conditions in the experimental range were determined to be: pH = 7.0, 0%-0.01% (w/v) NaCl, 4000 mg/L of MLSS, and 500 mg/L of glucose as co-substrate. FT-IR analysis indicated that PDM molecules biodegradation partly. The microbial community structures and dehydrogenase activity analysis revealed that PDM showed some toxicity to microorganisms in activated sludge. The effects of several parameters, including the pH and chemical doses, were investigated for removing PDM in Fenton oxidation process. The optimal Fenton oxidation process conditions in the experimental range were pH = 2.0, Fe2+ concentration of 40 mg/L, and H2O2 dosage of 23 mL/L. PDM was treated by biodegradation and subsequent Fenton oxidation under the optimal operating conditions. The removal efficiency was 44.5% after the biodegradation process and further increased to 85.5% after Fenton oxidation. The combined process was revealed to be a promising solution for achieving effective and economical removal of PDM.

Solochrome cyanine: A histological stain for cobalt-chromium wear particles in metal-on-metal periprosthetic tissues.

Metal-on-metal (MoM) hip arthroplasties produce abundant implant-derived wear debris composed mainly of cobalt (Co) and chromium (Cr). Cobalt-chromium (Co-Cr) wear particles are difficult to identify histologically and need to be distinguished from other wear particle types and endogenous components (e.g., haemosiderin, fibrin) which may be present in MoM periprosthetic tissues. In this study we sought to determine whether histological stains that have an affinity for metals are useful in identifying Co-Cr wear debris in MoM periprosthetic tissues. Histological sections of periprosthetic tissue from 30 failed MoM hip arthroplasties were stained with haematoxylin-eosin (HE), Solochrome Cyanine (SC), Solochrome Azurine (SA) and Perls' Prussian Blue (PB). Sections of periprosthetic tissue from 10 cases of non-MoM arthroplasties using other implant biomaterials, including titanium, ceramic, polymethylmethacrylate (PMMA) and ultra-high molecular weight polyethylene (UHMWP) were similarly analysed. Sections of 10 cases of haemosiderin-containing knee tenosynovial giant cell tumour (TSGCT) were also stained with HE, SC, SA and PB. In MoM periprosthetic tissues, SC stained metal debris in phagocytic macrophages and in the superficial necrotic zone which exhibited little or no trichrome staining for fibrin. In non-MoM periprosthetic tissues, UHMWP, PMMA, ceramic and titanium particles were not stained by SC. Prussian Blue, but not SC or SA, stained haemosiderin deposits in MoM periprosthetic tissues and TSGT. Our findings show that SC staining (most likely Cr-associated) is useful in distinguishing Co-Cr wear particles from other metal/non-metal wear particles types in histological preparations of periprosthetic tissue and that SC reliably distinguishes haemosiderin from Co-Cr wear debris.

Determination of residual poly diallyldimethylammonium chloride (pDADMAC) in monoclonal antibody formulations by size exclusion chromatography and evaporative light scattering detector.

The cationic polyelectrolyte pDADMAC is widely used in biopharmaceutical industry as a flocculating agent to enhance clarification throughput and downstream filtration operations. Due to the possible toxicity, pDADMAC should be assessed for an acceptable residual level to ascertain the safety of the product to patients. The strong protein-polyelectrolyte interaction, however, can negatively affect sensitivity and accuracy of measurements. This paper reports on the application of size exclusion (SE) chromatography coupled to evaporative light scattering detector (ELSD) to the quantitative determination of pDADMAC in monoclonal antibody formulations and in process intermediates during downstream purification. The SE chromatography was performed under isocratic condition with a mobile phase consisting of 0.1% TFA in water (90%) and acetonitrile (10%) at a flow rate of 0.4 ml/min. A quantification limit (S/N = 10) of 0.85 ppm was achieved in sample matrix, which is sufficiently low for the trace analysis of this compound in protein-containing samples.

Wear Mechanism of Artificial Joint Failure Using Wear Debris Analysis.

Aseptic loosening is one of the main failure modes in artificial joints. Significant information about the aseptic loosening is carried by the wear debris of the joints. In this paper, the wear debris acquired from the ultrahigh molecular weight polyethylene (UHMWPE) artificial joints is prepared and a systematic research is carried out to investigate the wear mechanism of aseptic loosening using the wear debris analysis. The hip joint simulator was used to conduct the wear tests of the CoCrMo-UHMWPE artificial joint friction pairs. The scanning electron microscope (SEM) was employed to analyze the wear debris profiles. The analysis results demonstrated that the UHMWPE joints mainly produced the roundness, tuberous, lacerated, sheet, pole-liked and strip wear debris, and the wear mechanism of the joint aseptic loosening had a close relationship with the morphology of the debris types. The adhesive wear, fatigue wear and laceration under alternating stress were the main causes of the joint failure. Based on the wear debris analysis results, a new diagnosis method using the radar map fractal representation was proposed to diagnose the failure of the artificial joints.

Cross-linked polyethylene does not reduce wear in total knee arthroplasty. / El polietileno de alto entrecruzamiento no reduce el desgaste en la artroplastia total de rodilla.

AIM: To compare two different types of inserts: Ultra-high molecular weight polyethylene (UHMWPE) and cross-linked polyethylene with a quantitative and qualitative study of polyethylene wear particles in synovial fluid 3 years after total knee arthroplasty. MATERIAL AND METHODS: A prospective, randomized, controlled cohort study with blinded evaluation was carried out on 25 patients undergoing staged bilateral total knee replacement, 6 months apart. Knee arthrocentesis was performed on 12 patients 3 years after surgery, and the polyethylene particles were analyzed. RESULTS: No significant differences were found in the number of particles generated by the two different types of inserts at 3 years from total knee arthroplasty (3,000×: x¯ cross-linked=849.7; x¯ UHMWPE=796.9; P=.63; 20,000×: x¯ cross-linked=66.3; x¯ UHMWPE=73.1; P=.76). Likewise, no differences in the probability of finding elongated (χ2=0.19; P=.66) or rounded (χ2=1.44; P=.23) particles in both types of inserts were observed. However, the probability of finding fibrillar particles is 3.08 times greater in UHMWPE. CONCLUSIONS: Cross-linked polyethylene does not significantly reduce the generation of polyethylene particles in patients with total knee arthroplasty, 3 years after the surgical procedure.

The impact of surface and geometry on coefficient of friction of artificial hip joints.

Coefficient of friction (COF) tests were conducted on 28-mm and 36-mm-diameter hip joint prostheses for four different material combinations, with or without the presence of Ultra High Molecular Weight Polyethylene (UHMWPE) particles using a novel pendulum hip simulator. The effects of three micro dimpled arrays on femoral head against a polyethylene and a metallic cup were also investigated. Clearance played a vital role in the COF of ceramic on polyethylene and ceramic on ceramic artificial hip joints. Micro dimpled metallic femoral heads yielded higher COF against a polyethylene cup; however, with metal on metal prostheses the dimpled arrays significantly reduced the COF. In situ images revealed evidence that the dimple arrays enhanced film formation, which was the main mechanism that contributed to reduced friction.

Equivalent wear performance of dual mobility bearing compared with standard bearing in total hip arthroplasty: in vitro study.

PURPOSE: Osteolysis in total hip arthroplasty (THA) depends on polyethylene wear and dictates the survival of the prosthesis. Dual mobility in THAs, which is claimed to reduce dislocation risk, has very good long-term clinical results. However, little is known about how the liner wears in this design, compared to the standard single mobility model. METHODS: A comparative study looking at wear of a conventional ultra-high-molecular-weight polyethylene liner, using gravimetric measurement, between dual mobility implants and standard implants, was performed on a simulator in accordance with a normed protocol based on the same dimensions, environmental conditions and stresses. A linear regression test was employed. RESULTS: Under the same conditions (loading, cycles, sterilization, material and surface roughness), the gravimetric wear (for conventional polyethylene) is comparable between a standard and a dual mobility cup. This correlates to ten year follow-up results of dual mobility cup. DISCUSSION - CONCLUSION: This in vitro equivalent wear serves to confirm the very good long-term clinical results observed with dual mobility bearing, whose use should not be restricted by concerns about increased polyethylene wear.

The coefficient of friction of UHMWPE along an entire walking cycle using a ball-on-disc tribometer under arthrokinematics and loading conditions prescribed by ISO 14243-3:2014.

The observation of tribological phenomena occurring in total knee replacement (TKR) simulators may be obscured by the intrinsic complexity of their operation: the dynamics and kinematics prescribed by the ISO 14243-3:2014 standard, and the geometry of the surfaces involved. On the other hand, evaluating the individual performance of the tribosystem elements may be carried out in simpler apparatuses. An experimental method is presented here, by means of which the arthrokinematics and loading conditions prescribed by the said standard are adapted to a ball-on-disc configuration in order to observe the behavior of the coefficient of friction along an entire walking cycle, using the contact point of an AISI 316L stainless steel ball rolling/sliding on an ultra-high molecular weight polyethylene (UHMWPE) disc, lubricated by a solution of fetal bovine serum, at 37°C. The method was tried on two different testing fluids prepared with protein concentrations of 20g/L, according to the said standard, and 36g/L, as received. The statistical model obtained for the behavior of the COF during the entire walking cycle may be used in numerical simulations of UHMWPE wear, under the conditions established by ISO 14243-3:2014.

Review of the partitioning of chemicals into different plastics: Consequences for the risk assessment of marine plastic debris.

Marine plastic debris are found worldwide in oceans and coastal areas. They degrade only slowly and contain chemicals added during manufacture or absorbed from the seawater. Therefore, they can pose a long-lasting contaminant source and potentially transfer chemicals to marine organisms when ingested. In order to assess their risk, the contaminant concentration in the plastics needs to be estimated and differences understood. We collected from literature plastic water partition coefficients of various organic chemicals for seven plastic types: polydimethylsiloxane (PDMS), high-density, low-density and ultra-high molecular weight polyethylene (LDPE, HDPE, UHMWPE), polystyrene (PS), polypropylene (PP), and polyvinyl chloride (PVC). Most data was available for PDMS (1060) and LDPE (220), but much less for the remaining plastics (73). Where possible, regression models were developed and the partitioning was compared between the different plastic types. The partitioning of chemicals follows the order of LDPE≈HDPE≥PP>PVC≈PS. Data describing the impact of weathering are urgently needed.

A Simple and Rapid Method Based on Anti-aggregation of Silver Nanoparticles for Detection of Poly(diallyldimethylammonium chloride) in Tap Water.

A simple and rapid method was developed for the detection of poly(diallyldimethylammonium chloride) (PDADMAC) using citrate-capped silver nanoparticles (AgNPs). Detection was based on anti-aggregation of AgNPs in phosphate buffer caused by PDADMAC. Due to its positive charges, PDADMAC was adsorbed onto AgNPs via electrostatic interaction with citrate, which resulted in the charges at the particle surfaces to become positive and caused repulsion among particles. Furthermore, long-chain PDADMAC provided steric hindrance. These two effects promoted the dispersion of AgNPs in the phosphate buffer. A change in the state of dispersion influenced the surface plasmon resonance (SPR) of AgNPs. Therefore, in this work, the concentration of PDADMAC was determined by monitoring changes in absorbance (at 396 nm) caused by SPR of AgNPs. Under optimal conditions, the calibration was linear over the range of 1 to 100 mg L(-1) with a detection limit of 0.7 mg L(-1). Satisfactory precision was obtained (RSD = 2.8%). This method was successfully applied to the determination of PDADMAC in tap water samples. The recoveries ranged from 86.0 - 107.5%.

Determination of microplastic polyethylene (PE) and polypropylene (PP) in environmental samples using thermal analysis (TGA-DSC).

Microplastics are increasingly detected in the environment and the consequences on water resources and ecosystems are not clear to date. The present study provides a cost-effective and straightforward method to determine the mass concentrations of polymer types using thermal analysis. Characteristic endothermic phase transition temperatures were determined for seven plastic polymer types using TGA-DSC. Based on that, extracts from wastewater samples were analyzed. Results showed that among the studied polymers, only PE and PP could be clearly identified, while the phase transition signals of the other polymers largely overlap each other. Subsequently, calibration curves were run for PE and PP for qualitative measurements. 240 and 1540mg/m(3) of solid material (12µm to 1mm) was extracted from two wastewater effluent samples of a municipal WWTP of which 34% (81mg/m(3)) and 17% (257mg/m(3)) could be assigned to PE, while PP was not detected in any of the samples. The presented application of TGA-DSC provides a complementary or alternative method to FT-IR analyses for the determination of PE and PP in environmental samples.