Ozonized water as a promising strategy to remove biofilm formed by Pseudomonas spp. on polyethylene and polystyrene surfaces.

The dairy industry faces challenges in controlling spoilage microorganisms, particularly Pseudomonas, known to form resilient biofilms. Conventional disinfection methods have limitations, prompting the exploration of eco-friendly alternatives like ozone. This study focused on Pseudomonas biofilms on polystyrene and polyethylene surfaces, evaluating ozone efficacy when incorporated into different water sources and applied under static and dynamic conditions. Biofilm formation and removal were assessed with conventional microbiological and microscopic techniques. Despite variations in physicochemical properties, ozonized water from different sources showed similar effectiveness in removing Pseudomonas biofilms. Dynamic ozone application was more efficient, achieving a 2.35 log CFU/coupon reduction on polyethylene surfaces, compared to a 1.05 log CFU/coupon reduction under static conditions. These findings highlight the potential of ozonized water for removing Pseudomonas biofilms, especially under dynamic application. This eco-friendly approach could serve as an effective strategy to mitigate biofilm-related challenges in the dairy industry.

Evaluation of perforation-mediated modified atmosphere packaging for the commercialization of bulk purple passion fruit under refrigeration.

Modified atmosphere packaging (MAP) is widely used to preserve fresh fruits. In the case of exporting products in bulk formats (2-5 kg), perforated MAP can help extend shelf life if appropriately configured to reach suitable gas levels. This study evaluated the configuration of a perforated MAP system for purple passion (Passiflora edulis Sims) fruits based on modeling and simulation of changes in gas levels within the package headspace and experimental data on the respiration and transpiration of the fruits. For this evaluation, perforation-mediated multilayer bags made of polyamide and low-density polyethylene were adjusted to preserve 2 kg of purple passion fruits. The number of perforations made in the bags was predefined by performing predictive calculations to reach favorable gas levels in the packaging headspace. Subsequently, storage tests were conducted at the laboratory level (6 and 17 ± 1°C) and then at the pilot level (6 ± 2 and 17 ± 3°C), obtaining steady molar fractions of O2 of 0.122-0.128 and CO2 of 0.098-0.100 and shelf life of 36 days for the fruits packaged at 6°C. Additionally, the accumulated weight loss of the fruits was monitored, obtaining values close to those previously modeled. The pre-configuration of the perforations resulted in suitable O2 and CO2 levels in the MAP, achieving up to 36 days of shelf life at 6°C and 24 days at 17°C. Likewise, moisture permeation through the bags resulted in low condensation with fruit weight losses of 4.8% at 6°C after 55 days in the pilot test. PRACTICAL APPLICATION: This study evaluated using perforated PA/LDPE multilayer bulk bags (2 kg) to preserve purple passion fruits. The package was preconfigured (with a predefined number of perforations necessary to achieve favorable levels of O2, CO2, and humidity) and was compared against a commercial factory-made perforated package. By performing predictive calculations to define a suitable number of perforations, it was possible to regulate the respiration and transpiration of the packaged fruit to increase its shelf life under controlled and real conditions. This approach can be extended to any bulk-packaged fruit, and it can help select, design, and develop breathable packages that prevent decay.

Sustainability synergies and trade-offs considering circularity and land availability for bioplastics production in Brazil.

Alongside the concerns of waste management, plastic production represents a future problem for managing greenhouse gas emissions. Advanced recycling and bio-based production are paramount to face this challenge. The sustainability of bio-based polyethylene (bioPE) depends on the feedstock, avoiding stress on natural resources. This work discusses Brazil's potential to meet future global bioPE demand by 2050, using sugarcane as feedstock and considering environmental sustainability for production expansion. From the assessed 35.6 Mha, 3.55 Mha would be exempt from trade-offs related to land use change (dLUC), biodiversity, and water availability. The scenario with the highest circularity efficiency would require 22.2 Mha to meet the global demand, which can be accommodated in areas with positive impacts in carbon stocks, neutral impacts in water availability, and medium impacts on biodiversity. Here, we show that dropping demand is essential to avoid trade-offs and help consolidate bioPE as a sustainable alternative for future net-zero strategies.

Enhanced degradation of phototreated recycled and unused low-density polyethylene films by Pleurotus ostreatus.

Polyethylene, one of the most used petroleum-derived polymers, causes serious environmental pollution. The ability of Pleurotus ostreatus to degrade UV-treated and untreated recycled and unused (new) low-density polyethylene (LDPE) films was studied. We determined the fungal biomass production, enzyme production, and enzyme yield. Changes in the chemical structure and surface morphology of the LDPE after fungal growth were analyzed using FTIR spectroscopy and SEM. Functional group indices and contact angles were also evaluated. In general, the highest Lac (6013 U/L), LiP (2432 U/L), MnP (995 U/L) and UP (6671 U/L) activities were observed in irradiated recycled LDPE (IrRPE). The contact angle of all samples was negatively correlated with fermentation time; the smaller the contact angle, the longer the fermentation time, indicating effective biodegradation. The IrRPE samples exhibited the smallest contact angle (49°) at 4 weeks, and the samples were fragmented (into two pieces) at 5 weeks. This fungus could degrade unused (new) LDPE significantly within 6 weeks. The biodegradation of LDPE proceeded faster in recycled than in unused samples, which can be enhanced by exposing LDPE to UV radiation. Enzymatic production during fungal growth suggest that LDPE degradation is initiated by laccase (Lac) followed by lignin peroxidase (LiP), whereas manganese peroxidase (MnP) and unspecific peroxygenase (UP) are involved in the final degradation process. This is the first experimental study on the fungal growth and its main enzymes involved in LDPE biodegradation. This fungus has great promise as a safe, efficient, and environmentally friendly organism capable of degrading LDPE.

Fracture Resistance and Failure Mode of Polyethylene Fiber-reinforced Resin-based Restorations in Structurally Compromised Premolars: an in Vitro Study.

OBJECTIVE: To evaluate the effect of polyethylene fiber-reinforcement on the fracture resistance and fracture mode of extensive resin-based composite (RBC) restorations in structurally compromised maxillary premolars. METHODS AND MATERIALS: Maxillary premolars (54) with specific dimensions and extracted for orthodontic reasons were used. Following mesio-occluso-distal (MOD) cavity preparation and endodontic access, teeth were randomly assigned to one of three restorative protocols (n=18): RBC applied incrementally (I) or reinforced with woven polyethylene fibers (Ribbond) placed horizontally (H) or U-shaped (U). Restored teeth were stored for 45 days in distilled water at 37°C and then loaded monotonically until fracture. Half of the specimens in each group received axial loading (A) and the other half was loaded paraxially (PA). Fracture load data was assessed using two-way analysis of variance and Tukey's post hoc test for multiple comparisons (α=0.05). The fracture initiation and propagation path were analyzed using stereomicroscopy and scanning-electron microscopy. RESULTS: No significant differences were observed for the fracture strength among loading configurations, except for groups IA (825 N) and HA (553 N). Fracture initiated and propagated mainly at and through the RBC restoration in the I group, whereas a shift to the interface was observed in both polyethylene fiber-reinforced groups. Blocking and bridging of cracks were identified around the fibers, especially in specimens of group U. CONCLUSIONS: Incorporation of woven polyethylene fibers to reinforce extensive MOD resin-based composite restorations on endodontically treated premolars reduced the occurrence of cohesive fractures in the restorative material but was unable to increase the fracture resistance of the affected teeth.

Behavioral and physiological responses of Girardia tigrina exposed to polyethylene microplastics.

Microplastic particles appear in great abundance and variety in freshwater ecosystems across the globe, spanning lakes and rivers, with increasingly frequent exposure of aquatic organisms. Studies on the mechanisms of any effects of plastic particles are still scarce, particularly in relation to the regenerative capacity of biota, for which there is no established model organism; however, planaria have shown sensitivity for assessing these risks to the aquatic environment. Thus, the present study aimed to investigate the behavioral and regeneration responses of the freshwater planaria Girardia tigrina exposed to polyethylene (PE) microplastics (MPs) incorporated into their food source. The greatest effect was observed on planarian regeneration, which was manifested at 10 µg/mg liver. Planaria reproduction and fertility were affected at 50 µg/mg liver; however, planaria locomotion was not affected at the concentrations evaluated. Mid-infrared absorption spectroscopy (FT-IR) was used to identify the constituent polymers, and ingestion of the polyethylene microplastic by the planaria was confirmed by infrared spectroscopy. The results highlight the potential adverse effects of exposure to polyethylene microplastic and show that the reproductive behavior and regeneration of a freshwater organism can be indicators of toxicity resulting from environmental pollution.

Multi-Biomarkers' Responses in Gills of Oreochromis niloticus Exposed to Glyphosate and Polyethylene Microplastic, Isolated and in Mixture.

Microplastics (MPs) and glyphosate-based herbicides (GBH) are among the most common contaminants in aquatic environments. In Brazilian rivers, both contaminants were found in elevated levels, leading to a high probability of their association, which can alter their individual effects and potentially intensify their toxicity. This study evaluated the isolated and combined effects of polyethylene microplastics (PE-MPs) and GBH on Oreochromis niloticus using multi-biomarkers of toxicity. The fish were subjected to a 96-h exposure period, with concentrations set based either isolated, PE-MPs group (5 mg L-1), GBH group (5 mg L-1), or in a group of associated contaminants (GAC), PE-MP + GBH (5 mg L-1 + 5 mg L-1). Toxicity effects were evaluated using biochemical, cytogenetic, hematological, and histopathological biomarkers. We observed change in erythrocyte parameters leading to macrocytic normochromic anemia in GAC. Leukocyte parameters indicate a nonspecific immunosuppression caused by the exposure of associated contaminants, besides the attempts to repair damage caused by PE-MPs. Histopathological markers indicate damage to tissues exposed to contaminants. Besides, there were morphophysiological adjustments on gills, with proliferation and hypertrophy of mitochondria-rich cells on GBH and GAC, besides epithelium ruptures, which were mostly present in the exposed groups. Therefore, this study indicates that PE-MPs and GBHs present toxic effects in O. niloticus with the used concentrations, intensified by the association of contaminants. Thus, multi-biomarkers were useful key to verify toxicity, providing data to the investigation of high levels of contaminant's mixture toxicity present in aquatic environments.

Interactive effects between water temperature, microparticle compositions, and fiber types on the marine keystone species Americamysis bahia.

Recently, there has been an increasing emphasis on examining the ecotoxicological effects of anthropogenic microparticles (MPs), especially microplastic particles, and related issues. Nevertheless, a notable deficiency exists in our understanding of the consequences on marine organisms, specifically in relation to microfibers and the combined influence of MPs and temperature. In this investigation, mysid shrimp (Americamysis bahia), an important species and prey item in estuarine and marine food webs, were subjected to four separate experimental trials involving fibers (cotton, nylon, polyester, hemp; 3 particles/ml; approximately 200 µm in length) or fragments (low-density Polyethylene: LDPE, polylactic acid: PLA, and their leachates; 5, 50, 200, 500 particles/ml; 1-20 µm). To consider the effects in the context of climate change, three different temperatures (22, 25, and 28 °C) were examined. Organismal growth and swimming behavior were measured following exposure to fragments and microfibers, and reactive oxygen species and particle uptake were investigated after microfiber exposure. To simulate the physical characteristics of MP exposure, such as microfibers obstructing the gills, we also assessed the post-fiber-exposure swimming behavior in an oxygen-depleted environment. Data revealed negligible fragment, but fiber exposure effects on growth. PLA leachate triggered higher activity at 25 °C and 28 °C; LDPE exposures led to decreased activity at 28 °C. Cotton exposures led to fewer behavioral differences compared to controls than other fiber types. The exposure to hemp fibers resulted in significant ROS increases at 28 °C. Microfibers were predominantly located within the gastric and upper gastrointestinal tract, suggesting extended periods of residence and the potential for obstructive phenomena over the longer term. The combination of increasing water temperatures, microplastic influx, and oxidative stress has the potential to pose risks to all components of marine and aquatic food webs.

Sonicated polyethylene terephthalate nano- and micro-plastic-induced inflammation, oxidative stress, and autophagy in vitro.

The environmental presence of nano- and micro-plastic particles (NMPs) is suspected to have a negative impact on human health. Environmental NMPs are difficult to sample and use in life science research, while commercially available plastic particles are too morphologically uniform. Additionally, this NMPs exposure exhibited biological effects, including cell internalization, oxidative stress, inflammation, cellular adaptation, and genotoxicity. Therefore, developing new methods for producing heterogenous NMPs as observed in the environment is important as reference materials for research. Thus, we aimed to generate and characterize NMPs suspensions using a modified ultrasonic protocol and to investigate their biological effects after exposure to different human cell lines. To this end, we produced polyethylene terephthalate (PET) NMPs suspensions and characterized the particles by dynamic light scattering and scanning electron microscopy. Ultrasound treatment induced polymer degradation into smaller and heterogeneous PET NMPs shape fragments with similar surface chemistry before and after treatment. A polydisperse suspension of PET NMPs with 781 nm in average size and negative surface charge was generated. Then, the PET NMPs were cultured with two human cell lines, A549 (lung) and HaCaT (skin), addressing inhalation and topical exposure routes. Both cell lines interacted with and have taken up PET NMPs as quantified via cellular granularity assay. A549 but not HaCaT cell metabolism, viability, and cell death were affected by PET NMPs. In HaCaT keratinocytes, large PET NMPs provoked genotoxic effects. In both cell lines, PET NMPs exposure affected oxidative stress, cytokine release, and cell morphology, independently of concentration, which we could relate mechanistically to Nrf2 and autophagy activation. Collectively, we present a new PET NMP generation model suitable for studying the environmental and biological consequences of exposure to this polymer.

Detection of plastic, cellulosic micro-fragments and microfibers in Laternula elliptica from King George Island (Maritime Antarctica).

It is generally acknowledged that microplastic pollutants are prevalent in ocean waters and sediments across a range of tropical, temperate, subpolar, and polar regions. The waters surrounding King George Island are significantly impacted by human activities, particularly those related to scientific stations, fishing, and tourism. Organisms, such as Laternula elliptica, can be used as environmental monitors due to the likelihood that they will bioaccumulate pollutants. The goal of this study was to quantify and identify plastic and cellulosic micro-fragments and microfibers present in the soft body of clams (n = 21), collected from Fildes Bay near sewage and wastewater discharges. Plastic and cellulose microfragments and microfibers were counted, and their compositions were determined using FT-IR. All 21 individuals sampled contained fragments and fibers, with a total of 900 items detected (42.86 ± 25.36 mean ± SD items per individual), or 1.82 items g.wet mass-1. 58 % of items were cellulose and 22 % plastic. Considering the plastic polymer compositions, 28.57 % were polyethylene terephthalate (PET), 21.43 % acrylic, 14.29 % high-density polyethylene (HDPE), 14.29 % Polypropylene (PP), 7.14 % ultra-high drawn polyethylene filament (UHMWPE), 7.14 % polyester and 7.14 % Polyethylene. The quantities and prevalence of MP in L. elliptica were higher than those found in other Antarctic marine species, and even in bivalves from populated regions of the world. Our work assessed the pollution status of L. elliptica near an effluent of wastewater plants and found that 95 % of individuals displayed MP and 100 % microfibers that could impact their population.

Evaluation the stress distribution in root canals by 3D finite element analysis after the materials used in reattaching the vertically root fractured fragments.

The aim was to evaluate the effect of stress distribution on vertical, horizontal, and oblique forces on the tooth model after reattaching the fragments of the maxillary incisor with vertical root fracture (VRF) using different materials, by 3D finite element analysis (FEA). Tooth with a root canal, spongious, and cortical bone models were designed. VRF was modeled on a tooth with 4 different re-attachment models: Group 1: dual-cure cement (DC)+fiber reinforced composite (FRC), Group 2: DC+polyethylene fiber, Group 3: DC+glass fiber, and Group 4:DC. 100 N force was applied in 3 different directions. Maximum principal stresses (σmax) of dentin, and re-attachment materials were evaluated on colored images. The highest σmax values ​​were on the repair materials under vertical forces for Groups 1 and 4, respectively; Groups 2 and 3 showed similarity. The highest σmax values in repair materials under horizontal and oblique forces were observed in Group 3 however the lowest σmax values in repair materials under oblique and horizontal forces were observed in Group 1. The stress values ​​on repair materials gradually increased respectively starting from horizontal to vertical. As the elasticity modulus of the repair materials increased, the stress values ​​on root dentin increased. Through all force directions, except vertical forces, lower stress values were observed with FRC. The fracture resistance was bigger when using solely FRC or dual-cure resin cement in comparison to fiber-supported designs. Adding polyethylene fiber to re-restorations decreased stress values ​​compared to glass fiber addition. Therefore, when adding fibers, polyethylene fiber will be advantageous.

Interaction Between Endocrine Disruptors and Polyethylene Nanoplastic by Molecular Dynamics Simulations.

Nanoplastics (NPs) can come into contact with humans through different means such as ingesting contaminated food or exposure to contaminated air. Recent research indicates that these NPs can act as vectors for other contaminants. Further research is still needed to determine the effects of these interactions and whether they are significant under environmental conditions. Bisphenol A (BPA) and benzophenone (BZP) are possible contaminants that could be cotransported with NPs. Even in low concentrations, BPA and BZP can act as endocrine disruptors and have been linked to several diseases. In this study, we used molecular dynamics simulations to obtain the potential of mean force (PMF) profile between a polyethylene NP and a BPA/BZP molecule. The PMF shows a minimum of -8.0 kJ mol-1 for the BPA, whereas it is -23.5 kJ mol-1 for the BZP, meaning BZP has a much greater attractive potential to polyethylene than BPA. We can infer that the higher quantity of BPA's hydrogen bonds with the water contributes to the difference between BZP and BPA. The results indicate the need to address the possibility of NPs playing a role in the cotransport and bioaccumulation of contaminants in aquatic ecosystems.

Antimicrobial potential of linear low-density polyethylene food packaging with Ag nanoparticles in different carriers (Silica and Hydroxyapatite).

Silver nanoparticles incorporation into polymeric packaging aims to prevent microbiological contamination in food products, thus ensuring superior food safety and preservation. In this context, this study aimed to verify the antimicrobial efficacy of linear low-density polyethylene (LLDPE) films incorporated with silver nanoparticles (AgNPs) dispersed in silica (SiO2) and hydroxyapatite (HAP) carriers at different concentrations. AgNPs + carriers polymer films were characterized at 0.2, 0.4, and 0.6% concentrations using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), field emission gun-scanning electron microscope (FEG-SEM), thermogravimetric analyzer (TGA), differential scanning calorimetry (DSC), and migration in acidic and non-acidic simulants. Antimicrobial action was investigated on Gram-positive Staphylococcus aureus, Gram-negative Escherichia coli, and the Penicillium expansum and Fusarium solani fungi with antimicrobial activity by direct contact test and bacterial imaging by scanning electron microscopy. AgNPs addition to the LLDPE matrix did not interfere with the films' chemical and thermal properties and presented no significant migration to the external medium. For antimicrobial action, silver nanoparticles showed, in most concentrations, an inhibition percentage higher than 90% on all microorganisms studied, regardless of the carrier. However, a greater inhibitory action on S. aureus and between carriers was found, making hydroxyapatite more effective. The results indicated that nanostructured films with AgNPs + hydroxyapatite showed more promising antimicrobial action on microorganisms than AgNPs + silica, making hydroxyapatite with silver nanoparticle potentially useful in food packaging, improving safety and maintaining quality.

Effect of polyethylene fiber orientation on fracture resistance of endodontically treated premolars.

STATEMENT OF PROBLEM: Polyethylene fibers have been reported to improve the fracture resistance of endodontically treated teeth, but their optimal orientation is unclear. PURPOSE: The purpose of this in vitro study was to evaluate the effects of different fiber positions and orientations on the fracture resistance of endodontically treated premolar teeth. MATERIAL AND METHODS: One hundred endodontically treated maxillary premolars were divided into 2 groups according to the cavity design, mesio-occluso-distal and occluso-buccal, and each group was divided into 5 subgroups (n=10) according to the polyethylene fiber orientation on the pulpal floor: unidirectional horizontal (from mesial to distal), unidirectional vertical (from buccal to palatal), bidirectional (buccopalatal and mesiodistal), circular (around the walls), and without fibers (control group). The cavities were restored with fiber-reinforced composite resin and conventional composite resin. All the teeth were fractured with a universal testing machine and analyzed as catastrophic failure or reparable failure. A 1-way ANOVA was used to compare fracture strength values (α=.05). RESULTS: The tested groups with different fiber orientations showed significantly higher fracture load than the control group (P<.05). No statistically significant difference was observed among the fiber orientations (P>.05). Most of the favorable fractures were occlusal to the cemento-enamel junction, and adhesive failure were seen in the mesio-occluso-distal and occluso-buccal cavities. The highest percentage of unfavorable fractures and mixed failures was observed in the control group. CONCLUSIONS: The fiber orientation pattern in the mesio-occluso-distal and occluso-buccal cavities did not differ significantly in the fracture resistance of endodontically treated maxillary premolar teeth.

Effect of florfenicol on Piscirickettsia salmonis biofilm formed in materials used in salmonid nets, nylon and high-density polyethylene.

Piscirickettsiosis is the most prevalent bacterial disease affecting seawater salmon in Chilean salmon industry. Antibiotic therapy is the first alternative to counteract infections caused by Piscirickettsia salmonis. The presence of bacterial biofilms on materials commonly used in salmon farming may be critical for understanding the bacterial persistence in the environment. In the present study, the CDC Biofilm Reactor® was used to investigate the effect of sub- and over-MIC of florfenicol on both the pre-formed biofilm and the biofilm formation by P. salmonis under the antibiotic stimuli on Nylon and high-density polyethylene (HDPE) surfaces. This study demonstrated that FLO, at sub- and over-MIC doses, decreases biofilm-embedded live bacteria in the P. salmonis isolates evaluated. However, it was shown that in the P. salmonis Ps007 strain the presence of sub-MIC of FLO reduced its biofilm formation on HDPE surfaces; however, biofilm persists on Nylon surfaces. These results demonstrated that P. salmonis isolates behave differently against FLO and also, depending on the surface materials. Therefore, it remains a challenge to find an effective strategy to control the biofilm formation of P. salmonis, and certainly other marine pathogens that affect the sustainability of the Chilean salmon industry.

Impact of plasticization temperature on the mechanical properties of sports mouthguards / Impacto da temperatura de plastificação nas propriedades mecânicas de protetores bucais esportivo

Objective: Mouthguards can reduce or even prevent orofacial injuries. These devices are responsible for absorbing part of the energy of an impact force, while the remaining part is dissipated. The present study aimed to evaluate how the plasticization temperature of the sports mouthguards' manufacturing process influences their mechanical properties and protective potential. Material and Methods: Specimens were made according to different plasticization temperatures (85°C, 103°C, 121°C and 128°C) and different dental brands of EVA sheets (Bio-art and FGM). Plasticization temperatures were measured using a culinary thermometer (Term; TP300). The mechanical properties evaluated were: energy absorption capacity, deformation, and modulus of elasticity. Compression testing was carried out in the Emic universal testing machine with a speed of 600 mm/min to simulate a punch. Results: EVA sheets submitted to the highest temperatures (121°C and 128°C) had their energy absorption capacity reduced. In addition, the samples that plasticized at the lowest temperature (85°C) showed higher absorption capacity, lower elastic modulus, and less variation in its dimensions. It proved to be the most effective in protection and with greater durability. Conclusion: The plasticization temperature proved to be an influential factor in the absorption capacity of mouthguards, so the increase in temperature led to a reduction in this property, especially when higher than 120°C. In addition, the plasticization temperature may vary depending on the sheet brand used. Finally, the kitchen thermometer used proved to be efficient and practical, thanks to its easy-to-read display and wide availability on the market. (AU)

Objetivo: Os protetores bucais são capazes de reduzir ou mesmo prevenir lesões orofaciais. Esses dispositivos são responsáveis por absorver parte da energia de uma força de impacto, enquanto a parte restante é dissipada. Este estudo teve como objetivo avaliar como a temperatura de plastificação de protetores bucais esportivos influencia em suas propriedades mecânicas e no seu potencial protetivo. Material e Métodos: Foram confeccionados modelos de trabalho segundo diferentes temperaturas de plastificação (85°C, 103°C, 121°C e 128°C) e distintas marcas odontológicas de placas de EVA (Bio-art e FGM). As temperaturas de plastificação foram medidas com termômetro culinário da marca Term/TP300. As propriedades mecânicas avaliadas foram capacidade de absorção de energia, deformação e módulo de elasticidade. O teste de compressão foi realizado na máquina de ensaios universal Emic com velocidade de 600 mm/min, a fim de simular um soco. Resultados: As placas de EVA submetidas às mais altas temperaturas (121°C e 128°C) tiveram sua capacidade de absorção de energia reduzida. Além disso, as amostras que plastificaram na temperatura mais baixa (85°C) apresentaram maior capacidade de absorção, menor módulo de elasticidade e menor variação em suas dimensões. Assim, mostraram-se a mais eficaz na proteção e com maior durabilidade. Conclusão: A temperatura de plastificação demonstrou ser um fator influente na capacidade de absorção dos protetores bucais, de modo que o aumento da temperatura levou a uma redução desta propriedade, principalmente quando superior a 120°C. Além disso, a temperatura de plastificação pode variar dependendo da marca comercial utilizada. Por fim, o termômetro culinário utilizado mostrou-se eficiente e prático, pela facilidade de leitura e por ser facilmente encontrado no mercado (AU)

Roles of inflammatory cell infiltrate in periprosthetic osteolysis.

Classically, particle-induced periprosthetic osteolysis at the implant-bone interface has explained the aseptic loosening of joint replacement. This response is preceded by triggering both the innate and acquired immune response with subsequent activation of osteoclasts, the bone-resorbing cells. Although particle-induced periprosthetic osteolysis has been considered a foreign body chronic inflammation mediated by myelomonocytic-derived cells, current reports describe wide heterogeneous inflammatory cells infiltrating the periprosthetic tissues. This review aims to discuss the role of those non-myelomonocytic cells in periprosthetic tissues exposed to wear particles by showing original data. Specifically, we discuss the role of T cells (CD3+, CD4+, and CD8+) and B cells (CD20+) coexisting with CD68+/TRAP- multinucleated giant cells associated with both polyethylene and metallic particles infiltrating retrieved periprosthetic membranes. This review contributes valuable insight to support the complex cell and molecular mechanisms behind the aseptic loosening theories of orthopedic implants.

Interaction of fluorene and its analogs with high-density polyethylene microplastics: An assessment of the adsorption mechanism to establish the effects of heteroatoms in the molecule.

The threat of microplastics (MP) pollution in aquatic ecosystems can be even more severe for they are able to interact with organic pollutants that can migrate to adjacent environments. The presence of heteroatoms in organic pollutants can directly influence adsorption onto MP. This research evaluated the adsorption of fluorene (FLN) and its heteroatom analogs dibenzothiophene (DBT), dibenzofuran (DBF) and carbazole (CBZ) onto high-density polyethylene (HDPE) MP from residual (HDPEres) and commercial (HDPEcom) sources. The Langmuir isotherm showed a better fit, while DBT showed higher maximum adsorption capacity (19.2 and 15.8 µmol g-1) followed by FLN (13.4 and 11.7 µmol g-1), and DBF (13.5 and 10.3 µmol g-1) to the HDPEcom and HDPEres, respectively, which indicates a direct correlation with the hydrophobicity of the molecules determined by Log Kow. In contrast, CBZ showed no significant interaction with MP, due to their polar characteristic, thus, no kinetic and thermodynamic parameters could be determined. The adsorption process of all PAH was determined to be exothermic and spontaneous, with low temperatures favoring the process. The pseudo-second-order kinetic models have fitted to the adsorption onto both HDPE; intraparticle diffusion was also observed. Computational studies, physical characterization techniques and batch adsorption experiments demonstrated that the mechanism is governed by hydrophobic interactions, with van der Waals forces as a secondary effect in the adsorption of FLN, DBT and DBF onto HDPEres and HDPEcom. Thus, allowing a deeper understanding of the interactions between HDPE MP and FLN as well with its derivatives.

An accessible method to standardize polyethylene microsphere (<100 µm) concentrations for zooplankton ingestion experiments.

The ubiquity of microplastics has caused alarm as to the impact of these materials on aquatic life, leading to experimental studies to understand these effects. In zooplankton bioassays, microspheres (Ms) are often used as a proxy to represent aquatic microplastic contamination due to their homogeneity and small sizes (<100 µm). The present study proposes an accessible protocol that does not require highly specialized equipment for the creation of Ms stock solutions and environmentally realistic experimental concentrations and describes some common issues. Adult females of the calanoid copepod Centropages furcatus underwent treatments of two Ms sizes at experimental concentrations of 10 Ms/mL. They consumed on average 0.9 ± 2.6 Ms/mL of 45-53 µm Ms, and 2.4 ± 1.1 Ms/mL of 38-45 µm Ms. The results are not directly comparable with other studies due to the wide variety of methods used but successfully demonstrate the reproducibility of the proposed protocol.

Restoration of a Vital Tooth With Extensive Crown Destruction Using Glass Fiber and Polyethylene Fiber-reinforced Composite Resin: A Clinical Case.

Conservative restorative dentistry has been evolving in the last 25 years, focusing mainly on the development of direct restorative materials. Resin-based composites remain an excellent conservative alternative for restoration of teeth with extensive caries lesions. Over time, several strategies have been proposed to improve the mechanical properties of these composites so that they can adequately withstand masticatory forces. Glass fiber-reinforced resin-based composites and their use in situations where there is great loss of tooth structure have gained popularity due to their favorable mechanical properties. Combined techniques with polyethylene fibers can further enhance their clinical performance. This study presents a brief review of their most important qualities and potential use in direct restorative procedures. In addition, a clinical case is described where a vital tooth with extensive coronal destruction was restored using polyethylene fibers embedded in glass fiber-reinforced flowable resin under resin-based composite. The reinforcement of both the remaining tooth structure and the restoration with fibers is a valid treatment option since the network structure formed by the fiber reinforcement can increase the longevity of the direct composite restorations. There are few reports in the literature describing the use of a combined technique using polyethylene fibers embedded in glass fiber-reinforced flowable resin under resin-based composite. Thus, clinical follow-up of this case is required.