Microplastic loads in Eurasian otter (Lutra lutra) feces-targeting a standardized protocol and first results from an alpine stream, the River Inn.

Microplastics (MP) are omnipresent in a wide range of environments, constituting a potential threat for aquatic and terrestrial wildlife. Effects in consumers range from physical injuries to pathological reactions. Due to potential bioaccumulation of MP, predators are of particular concern for MP induced health effects. The Eurasian otter is an apex predator in (semi-)aquatic habitats feeding primarily on fish. Furthermore, the species is classified as "near threatened" on the IUCN Red List. Thus, the Eurasian otter is of conservation concern and may serve as a bioindicator for MP pollution. Feces can be used to detect pollutants, including MP. Initial studies confirmed the presence of MP in otter feces (= spraints). However, as specific, validated protocols targeting at an efficient and standardized extraction of MP from otter spraints are missing, experimental results reported from different groups are challenging to compare. Therefore, we (i) present steps towards a standardized protocol for the extraction of MP from otter feces, (ii) give recommendations for field sample collection of otter spraints, and (iii) provide a user-friendly step-by-step workflow for MP extraction and analysis. Applying this framework to field samples from five study sites along the River Inn (n = 50), we detected MP of different sizes and shapes (ranging from microfibers to road abrasion and tire wear) in all otter spraint samples.

A Multi-Task Joint Learning Model Based on Transformer and Customized Gate Control for Predicting Remaining Useful Life and Health Status of Tools.

Previous studies have primarily focused on predicting the remaining useful life (RUL) of tools as an independent process. However, the RUL of a tool is closely related to its wear stage. In light of this, a multi-task joint learning model based on a transformer encoder and customized gate control (TECGC) is proposed for simultaneous prediction of tool RUL and tool wear stages. Specifically, the transformer encoder is employed as the backbone of the TECGC model for extracting shared features from the original data. The customized gate control (CGC) is utilized to extract task-specific features relevant to tool RUL prediction and tool wear stage and shared features. Finally, by integrating these components, the tool RUL and the tool wear stage can be predicted simultaneously by the TECGC model. In addition, a dynamic adaptive multi-task learning loss function is proposed for the model's training to enhance its calculation efficiency. This approach avoids unsatisfactory prediction performance of the model caused by unreasonable selection of trade-off parameters of the loss function. The effectiveness of the TECGC model is evaluated using the PHM2010 dataset. The results demonstrate its capability to accurately predict tool RUL and tool wear stages.

Manual toothbrushes, self-toothbrushing, and replacement duration to remove dental plaque and improve gingival health: A scoping review from recent research.

OBJECTIVE: To investigate characteristics of manual toothbrushes, self-toothbrushing methods, and replacement duration of manual toothbrushes that effectively remove dental plaque, reduce gingivitis, and promote gingival health. STUDY DATA AND SOURCES: PubMed-MEDLINE, Scopus and Central Register Cochrane of Controlled trials (CENTRAL) were searched for randomized control trials (RCTs) from 01 January 2018 to 12 December 2023. Articles were subjected for including participants aged six years and older with a study duration of at least four weeks to investigate the efficacy of manual toothbrushes used self-toothbrushing. To investigate the appropriate time to replace manual toothbrushes, this study was focused on the physical properties of the bristles and changes in the microorganisms present in the bristles over time. STUDY SELECTION: Of 1520 retrieved articles, 26 studies were included after screening. The total number of manual toothbrushes was 40 and 5 kinds of self-toothbrushing techniques were selected in the review. 4 studies investigated the changes the physical properties bristles of manual toothbrushes. CONCLUSIONS: Among manual toothbrushes, the cross-angle and indicator bristles were found to significantly improve dental plaque index and gingival condition. Most toothbrushes with soft bristles had a trend of superior dental plaque removal and gingivitis improvement efficacy. Toothbrush with end-round shape bristles tip has tended to reduce the dental plaque and gingival index scores. Studies reported that brushing twice a day for at least two minutes using the Bass method had a positive effect on the dental plaque and gingival index. Further research is required to investigate the relationships between property physical bristle and clinical intraoral indices to clarify the replacement duration of manual toothbrushes. CLINICAL SIGNIFICANCE: The findings of this study could guide people's daily self-brushing habits, thereby aiding the prevention of periodontal disease. Moreover, our findings suggest the need for strategic clinical trial designs to verify the ideal timing to replace manual toothbrushes.

Prevalence and Risk Factors of Bone and Dental Lesions in Neotropical Deer.

Bone and dental lesions have been documented in various deer species globally, affecting the efficiency of ingestion and digestion, consequently influencing their general health and leading to a decline in survival and reproductive performance. The present study aimed to characterize bone and dental lesions in the dry skulls of individual deer, estimate the prevalence of these lesions, and assess potential risk factors associated with the development of bone and dental alterations. This study assessed bone and dental lesions in 180 dry skulls of eleven neotropical deer species, originating from both captivity and wildlife conditions, through direct visual inspection. A high prevalence of bone and dental lesions was observed in all analyzed species. Dental calculus was the most common alteration (96.7%), followed by dental wear (71.1%). Animal age positively correlated with most bone and dental alterations, indicating that older animals showed more lesions. Additionally, the prevalence of these alterations was similar between sexes. Moreover, all lesions were more common in captive-bred animals, likely attributed to their older age and a less diverse diet. Blastocerus dichotomus and Mazama americana were most affected by bone resorption and dental trauma and had the highest dental calculus prevalence, along with Subulo gouazoubira and Passalites nemorivagus. All eleven species evaluated in the present study were susceptible to the occurrence of bone and dental lesions. Therefore, monitoring oral health and diet in captivity are fundamental practices for the conservation of these species.

Microstructure and Erosion Wear of In Situ TiC-Reinforced Co-Cr-W-C (Stellite 6) Laser-Cladded Coatings.

The article presents research results on the possibility of shaping the structure and properties of Co-Cr-W-C-Ti alloys (type Stellite 6) using laser cladding technology. Cobalt-based alloys are used in several industries because they are characterized by high erosion, abrasion, and corrosion resistance, retaining these properties at high temperatures. To further increase erosion resistance, it seems appropriate to reinforce material by in situ synthesis of hard phases. Among the transition metal carbides (TMCs), titanium carbide is one of the hardest and can have a positive effect on the extension of the lifetime of components made from cobalt-based alloys. In this article, concentration of C, W, and Ti due to the possibility of in situ synthesis of titanium carbides was subjected to detailed analysis. The provided research includes macrostructure and microstructure analysis, X-ray diffraction (XRD), microhardness, and penetrant tests. It was found that the optimal concentrations of Ti and C in the Co-Cr-W-C alloy allow the formation of titanium carbides, which significantly improves erosion resistance for low impact angles. Depending on the concentrations of titanium, carbon, and tungsten in the molten metal pool, it is possible to shape the alloy structure by influencing to morphology and size of the reinforcing phase in the form of the complex carbide (Ti,W)C.

Microstructural Characterization, Tribological and Corrosion Behavior of H111 Hot-Rolled AA5754 after Homogenization and Aging.

In this study, the microstructural properties, wear resistance, and corrosion behavior of H111 hot-rolled AA5754 alloy before heat treatment, after homogenization, and after aging were examined. The microstructure was mainly composed of the scattered forms of black and gray contrast particles on the matrix and precipitations were observed at the boundaries of the grain. The as-rolled material exhibited a dense pancake-shaped grain structure, which is typical of as-rolled material. Observation along the L-direction did not yield distinct demarcations among the grains and was not uniformly distributed, with precipitates at the grain boundary. When they aged, there was a parallel increase in fine and huge black and gray contrast particles in the zone. Therefore, it could be stated that the amount of fine grains increased due to the rise in the homogenization process. The rolled base metal with the grain orientation was found to be parallel to the rolling direction. On the other hand, the coarse grains were clearly observed in the aging heat-treatment condition. The grains had an elongated morphology consistent with the rolling process of the metal before the heat-treatment process. The aged alloy had the highest hardness with a value of 86.83 HB; the lowest hardness was seen in the alloy before heat treatment with a value of 68.67 HB. The weight loss and wear rate of this material at the end of 10,000 m were, respectively, 1.01 × 10-3 g and 5.07 × 10-9 g/Nm. It was observed that the alloy had the highest weight loss and worst wear resistance before heat treatment. Weight loss and wear rates at the end of 10,000 m were, respectively, 3.42 × 10-3 g and 17.08 × 10-9 g/Nm. According to these results, the friction coefficients during wear were parallel and the material with the lowest friction coefficient after aging was 0.045. While the alloys corroded after aging showed more weight loss, the alloys corroded before heat treatment exhibited better corrosion behavior. Among the alloys, the least weight loss after 24 h was observed in the alloy that was corroded before heat treatment and this value was 0.69 × 10-3 mg/dm2. The highest weight loss was observed in the aged alloy with a value of 1.37 × 10-3 mg/dm2. The alloy before heat treatment, which corroded after casting, showed the lowest corrosion rate with a value of 0.39 × 10-3 mg/(dm2·day) after 72 h. The alloy that was corroded before heat treatment showed the best corrosion behavior by creating a corrosion potential of 1.04 ± 1.5 V at a current density of -586 ± 0.04 µA/cm2. However, after aging, the corroded alloy showed the worst corrosion behavior with a corrosion potential of 5.16 ± 3.3 V at a current density of -880 ± 0.01 µA/cm2.

Ni-B-PTFE Nanocomposite Co-Deposition on the Surface of 2A12 Aluminum Alloy.

The spinning cup, a crucial component of textile equipment, relies heavily on 2A12 aluminum alloy as its primary raw material. Commonly, electroplating and chemical nickel-phosphorus (Ni-P) plating are employed to improve the surface characteristics of the object. Nevertheless, due to the growing expectations for the performance of aluminum alloys, the hardness and wear resistance of Ni-P coatings are no longer sufficient to fulfill industry standards. This study primarily focuses on the synthesis of Ni-B-PTFE nanocomposite chemical plating and its effectiveness when applied to the surface of 2A12 aluminum alloy. We examine the impact of the composition of the plating solution, process parameters, and various other factors on the pace at which the coating is deposited, the hardness of the surface, and other indicators of the coating. The research findings indicate that the composite co-deposited coating achieves its optimal surface morphology when the following conditions are met: a nickel chloride concentration of 30 g/L, an ethylenediamine concentration of 70 mL, a sodium borohydride concentration of 0.6 g/L, a sodium hydroxide concentration of 90 g/L, a lead nitrate concentration of 30 mL, a pH value of 12, a temperature of 90 °C, and a PTFE concentration of 10 mL/L. The coating exhibits consistency, density, a smooth surface, and an absence of noticeable pores or fissures. The composite co-deposited coating exhibits a surface hardness of 1109 HV0.1, which significantly surpasses the substrate's hardness of 232.38 HV0.1. The Ni-B-PTFE composite coating exhibits an average friction coefficient of around 0.12. It has a scratch width of 855.18 µm and a wear mass of 0.05 mg. This coating demonstrates superior wear resistance when compared to Ni-B coatings. The Ni-B-PTFE composite coating specimen exhibits a self-corrosion potential of -6.195 V and a corrosion current density of 7.81 × 10-7 A/cm2, which is the lowest recorded. This enhances its corrosion resistance compared to Ni-B coatings.

Fabrication of TiN Coatings Deposited on Laser Shock Micro-Textured Substrates for Improving the Interface Adhesion Properties of Coatings.

This paper aims to investigate the strengthening mechanism of laser shock peening on the interfacial bonding properties between TiN coatings and TC4 titanium alloy substrates. The different surface textures were induced by LSP on a TC4 titanium alloy substrate. Subsequently, titanium nitride (TiN) coatings were deposited on the surface texture. A scratch test and reciprocating sliding wear assessment were conducted to evaluate the impact of LSP on the interfacial bonding properties and wear performance of the coatings. The experimental results demonstrated that the adhesion of TiN coatings deposited on the surface texture formed by laser shock peening was significantly enhanced. The efficacy of laser shock treatment in reducing wear rates was found to be significantly enhanced in cases of both increased spot overlapping rate and increased laser power density. The surface texture created using laser parameters of 6.43 GW/cm2 and a 50% overlapping rate was found to have the most significant effect on improving the adhesion and anti-wear properties of the coating. The laser shock texture was identified as the main contributor to this improvement, providing a large interfacial contact area and a mechanical bond between the coating and the substrate. This bond inhibited the initiation and propagation of micro-cracks caused by the concentration of internal stress and interfacial stress of the coating.

Homogenization Heat Treatment for Enhancing Corrosion Resistance and Tribological Properties of the Al5083-H111 Alloy.

In this study, an Al5083-H111 alloy was divided into two different parameters without heat treatment and by applying homogenization heat treatment. In the homogenized Al5083 sample, it helped to make the matrix structure more homogeneous and refined and distribute intermetallic phases, such as the Al-Mg phase (Mg2Al3) and Al-Fe phases, more evenly in the matrix. There was an increase in the hardness of the homogenized sample. The increase in hardness is due to the material having a more homogeneous structure. Corrosion tests were applied to these parameters in NaCl and NaOH. It is observed that Al5083 samples before and after heat treatment show better corrosion resistance and less weight loss in NaOH and NaCl environments. It was observed that the fracture resistance of the alloy in the NaOH solution was lower, and the weight loss was higher than the alloy in the NaCl solution. Wear tests were performed on two different parameters: a dry environment and a NaOH solution. Since the NaOH solution has a lubricating effect on the wear surface of the sample and increases the corrosion resistance of the oxide layers formed, the wear resistance of the alloys in dry environments was lower than the wear resistance of the alloys in the NaOH solution. A hydrogen evolution test was performed on the samples in the NaOH solution, and the results were recorded. Hydrogen production showed higher hydrogen output from the homogenized sample. Accordingly, a higher corrosion rate was observed.

Performance and Antiwear Mechanism of 1D and 2D Nanoparticles as Additives in a Polyalphaolefin.

This work is focused on the thermophysical and tribological study of eight nanolubricant compositions based on a polyalphaolefin (PAO 20) and two different nanoadditives: multi-walled carbon nanotubes (MWCNTs) and hexagonal boron nitride (h-BN). Regarding the thermophysical properties, density and dynamic viscosity of the base oil and the nanolubricants were measured in the range of 278.15-373.15 K, as well as their viscosity index, with the aim of evaluating the variation of these properties with the addition of the nanoadditives. On the other hand, their lubricant properties, such as contact angle, coefficient of friction, and wear surface, were determined to analyze the influence of the nanoadditives on the tribological performance of the base oil. The results showed that MWCNTs and h-BN nanoadditives improved the wear area by 29% and 37%, respectively, at a 0.05 wt% concentration. The density and dynamic viscosity increased compared with the base oil as the nanoadditive concentration increased. The addition of MWCNTs and h-BN nanoparticles enhanced the tribological properties of PAO 20 base oil.

Bruxism in a Child with Trisomy 21 (Down Syndrome)-Case Report.

Bruxism has been defined in recent years and analyzed in detail as the repetitive activity of the muscles of the masticatory system. Both adults and children experience two different forms of bruxism: daytime and nighttime bruxism. According to the WHO, bruxism affects 5% to 50% of the world's pediatric population. The symptoms of this disease include tooth wear and fractures, temporomandibular disorders, headaches, behavioral and sleep disorders, and parafunctional habits such as nail biting. According to scientists, psychosocial factors are the most likely factors causing bruxism in children. To this day, we do not have established standards of treatment for children, especially for those with disabilities. The issue of bruxism in children with Down syndrome (DS) is still unexplained. Anatomical abnormalities in the facial skeleton, reduced muscle tone, personality traits, and sleep problems in these people may cause the symptoms of bruxism. Our study aimed to present a clinical case of a 13-year-old girl with DS and symptoms of bruxism. Diagnostics and dental examination in children with intellectual disabilities and a lack of understanding of the disease create a great challenge for the treatment team, including the dentist, physiotherapist, psychologist, and family. Creating standards for treating and preventing bruxism symptoms is demanding, among other things, due to the lack of sufficient scientific research.

A Study about Perceptions of Kimono among College Students and Kimono Enthusiasts: Is It Difficult to Move in a Kimono?

Background: Kimono is being reevaluated for its sustainability aspects, such as having fewer offcuts in the production process due to its structural differences from Western-style clothes and its high reusability due to the adaptability to individuals' body shapes. On the other hand, once a common attire for daily wear in Japan, kimono has transitioned to being worn only on special events and the kimono-related industry has also shrunk. To stimulate demand for kimono, it is essential to familiarize younger generations with its potential as daily wear. Methods: A questionnaire survey on perceptions of kimono was conducted among two groups in Japan: 211 college students and 50 kimono enthusiasts. The questionnaire included demographic questions and psychometric scales, primarily focusing on their kimono experiences, challenges associated with wearing kimono, their perceptions of kimono and Western-style clothes, and their attitudes towards kimono. Results: The results revealed that a majority of students had worn kimono before, though they found it difficult to move while wearing it. In contrast, kimono enthusiasts evaluated it as easier to move, hard to become disheveled, and casual. They also rated the ease of wearing Western-style clothes lower compared to students, and this tendency intensified with the length of enthusiast experience. Furthermore, the findings indicated that enthusiasts regarded the kimono more as daily wear compared to students, while still deriving enjoyment from it as formal attire in special events. Conclusions: These results suggest that the cognition that Western-style clothes are easy to move and kimono is not may change with experiences. Therefore, providing opportunities for people in Japan to acquire how to wear kimono in comfortable ways possibly impacts their perceptions of kimono.

Wear simulation of UHMWPE against the different counterface roughness in reciprocating unidirectional sliding motion.

Wear simulations of UHMWPE can economically and conveniently predict the performance of wear resistant bushings used for sealing or other reciprocating unidirectional sliding motion. In this study, pin on plate tribological experiments and microscopic analysis was done to obtained the wear profiles, wear volume and wear mechanism of UHMWPE against the counterface with different surface roughness of which Ra range is 0.03 ~ 2 µm. Meanwhile, the 3D wear simulation model of the pin on plate tribological experiments was established to discuss the adaptability of the energy and Archard wear model by analyzing the difference of wear profiles and wear volume between the experiment and simulation. The results indicate that with an increase in the counterface roughness, the wear simulation of UHMWPE estimated by the energy model were more accurate in reciprocating unidirectional sliding motion.

Assessing the prevalence and risk of tooth wear in Parkinson's disease: A narrative review.

Tooth wear is an increasingly common problem that affects the quality of life. Although previous research suggested that oral health is adversely affected in individuals with Parkinson's disease (PD) compared to healthy controls, tooth wear has not been extensively studied in this context. Particularly, there is a paucity of data on the prevalence and risk factors associated with tooth wear in PD patients. The aim of this study is to review the current literature on the prevalence and risk factors of tooth wear in PD patients and to propose hypotheses for future research on this topic. A literature search was conducted in PubMed. A total of 4 publications were identified: 1 case report and 3 questionnaire-based studies. These articles suggest that tooth wear is a more significant issue in PD patients than in healthy controls. In addition, potential associations between oral health-related quality of life (OHRQoL), bruxism and temporomandibular disorder (TMD) pain on the one hand, and tooth wear on the other hand, were identified in PD patients. Due to the limited number of articles published on this topic, it is not possible to definitively conclude whether tooth wear is a common problem in PD patients. However, the following hypotheses could be formulated: 1) tooth wear is more prevalent in PD patients than in healthy controls; 2) risk factors for tooth wear observed in healthy individuals are more prevalent among PD patients; and 3) multiple risk factors for tooth wear likely coexist in people with PD, potentially influencing the prevalence and progression of tooth wear in this population.

Mid-term survivorship and clinical results of cementless total hip arthroplasty for steroid-induced avascular necrosis.

OBJECTIVE: The purpose of the present study was to evaluate the mid-term implant survivorship, modes of failure, radiographic results, and clinical outcomes of current cementless total hip arthroplasty (THA) treatment designs for steroid-induced avascular necrosis (AVN). METHODS: A time span of 5 years between January 2012 and November 2017 was scanned to accommodate 5 years of follow-up and a total of 15 patients (18 hips), who had undergone implantation of ultra-high molecular weight polyethylene (UHMWPE) and newly designed other head and liner components, were included in the study. Only patients operated for steroid-induced AVN were included in the study. Patients with alcohol-induced, idiopathic, and traumatic AVN were excluded from the study. The primary outcomes were the assessments of Harris Hip Score (HHS) and the presence of loosening, osteolysis, polyethylene wear or a reoperation (with or without revision of components). The fixation of cementless femoral components was assessed according to Engh criteria. RESULTS: The study group consisted of 18 hips from 15 patients. The mean age was 47.6±8.1 (29-55) years. A cementless femoral stem and acetabular cup were used for all patients. Septic loosening was detected in all components of one patient (5.6%). The mean HHS score was 83.3±7.2 (60-92) for all patients. Of the 18 hips, 83% (15 hips), 5.6% (1 hip), 5.6% (1 hip), and 5.6% (1 hip) had good, poor, fair, and excellent HHS scores. Ceramic or polyethylene liner wear was not detected in any of the patients. The Engh Grading Scale revealed a "bone ingrowth" in 16 (89%) hips, "suspected in-growth" in 1 (5.6%) hip and "suboptimum but stable" femoral fixation in a patient with septic loosening (5.6%) just before revision surgery. There was no significant correlation between femoral stem design and Engh score (p=0.842). CONCLUSION: Modern total hip arthroplasty systems, including ceramic on ceramic or ceramic on polyethylene headliner options with cementless femoral stem, offer promising mid-term survivorship and positive clinical outcomes for steroid-induced AVN treatment. However, studies including long-term follow-ups with larger sample size are needed to obtain more precise data.

Assessing tooth wear progression in non-human primates: a longitudinal study using intraoral scanning technology.

Intraoral scanners are widely used in a clinical setting for orthodontic treatments and tooth restorations, and are also useful for assessing dental wear and pathology progression. In this study, we assess the utility of using an intraoral scanner and associated software for quantifying dental tissue loss in non-human primates. An upper and lower second molar for 31 captive hamadryas baboons (Papio hamadryas) were assessed for dental tissue loss progression, giving a total sample of 62 teeth. The animals are part of the Southwest National Primate Research Center and were all fed the same monkey-chow diet over their lifetimes. Two molds of each dentition were taken at either two- or three-year intervals, and the associated casts scanned using an intraoral scanner (Medit i700). Tissue loss was calculated in WearCompare by superimposition of the two scans followed by subtraction analysis. Four individuals had dental caries, and were assessed separately. The results demonstrate the reliability of these techniques in capturing tissue loss data, evidenced by the alignment consistency between scans, lack of erroneous tissue gain between scans, and uniformity of tissue loss patterns among individuals (e.g., functional cusps showing the highest degree of wear). The average loss per mm2 per year for all samples combined was 0.05 mm3 (0.04 mm3 for females and 0.08 mm3 for males). There was no significant difference in wear progression between upper and lower molars. Substantial variation in the amount of tissue loss among individuals was found, despite their uniform diet. These findings foster multiple avenues for future research, including the exploration of wear progression across dental crowns and arcades, correlation between different types of tissue loss (e.g., attrition, erosion, fractures, caries), interplay between tissue loss and microwear/topographic analysis, and the genetic underpinnings of tissue loss variation.

Prediction of formation abrasiveness under the action of a PDC bit based on the fractal dimension of a rock surface.

During rock drilling, a drill bit will wear as it breaks the rock. However, there is no uniform grading standard for rock abrasiveness. To solve this problem, the wear mechanisms of a polycrystalline diamond compact (PDC) bit and the formation it is drilling into are analyzed in depth, and an abrasiveness evaluation method based on the fractal dimension of the rock surface topography is established. Initially, a three-dimensional digital model is generated from a scanning electron microscope image of the rock after drilling; next, an evaluation of the irregularities on the rock surface is performed using an adapted Weierstrass-Mandelbrot (W-M) function to ascertain the fractal dimensionality. Then, the microcontact characteristics of the contact surface between the formation and the PDC bit are analyzed, and the distribution of the microconvex contact points of the two-body friction pair in a region is obtained. Because the sliding friction between the drill bit and the rock produces a large amount of heat, according to the contact area formula of the friction surface and heat conduction theory, the temperature rise and overall temperature distribution of the formation and PDC bit under the condition of sliding friction are revealed, and the real contact area between the formation and the drill bit within a certain temperature range is obtained. Finally, the evaluation index of rock abrasiveness under sliding conditions is established by adopting the wear weight loss of the rock cutting tool per unit volume as the index of rock abrasiveness, and the model is verified by a microdrilling experiment. The research in this paper is highly important for improving the rock-breaking efficiency and bit service life during drilling.

An in vitro comparison of the toxicological profiles of ground tire particles (TP) and actual tire and road wear particles (TRWP) emissions.

There is currently limited data on the potential effects of tire and road wear particles (TRWP) on human health. TRWP include tire fragments, but also road wear materials, dust, adsorbed gaseous pollutants and different types of inclusions that could affect their hazard profiles. Due to their availability and lower complexity, ground tire particles (TP) are often used in toxicological studies. However, this makes it difficult to draw firm conclusions about the potential hazard of actual TRWP. Here, we compared the in vitro toxicological profile of ground TP and actual TRWP emissions of similar size collected from road traffic. For this purpose, TP and TRWP were separately incubated with alveolar macrophages for 24 h, and the cellular response was evaluated in terms of cytotoxicity, proinflammatory response and oxidative stress. Both TP and TRWP induced neither significant cytotoxicity nor oxidative stress, but triggered a concentration-dependent proinflammatory response, as evidenced by increased TNF-α production. The level of TNF-α production was slightly higher with TRWP than with TP, independent of the particle dose. All in all, the pulmonary toxicity of TRWP could be due primarily to the tire tread inclusions and only marginally to other particle components (i.e. road wear materials, dust …). Although these preliminary results need to be confirmed by further analysis, they could be useful for tire manufacturers in the production of safer-by-design tires.

Combined toxicity of pristine or artificially aged tire wear particles and bisphenols to Tigriopus japonicus.

Tire wear particles (TWPs) are considered an important component of microplastic pollution in the marine environment and occur together with a variety of aquatic pollutants, including frequently detected bisphenols. The adverse effects of TWPs or bisphenols on aquatic organisms have been widely reported. However, the combined toxicity of TWPs and bisphenols is still unknown. In this study, the combined toxicity of both pristine (p-) and aged TWPs (a-TWPs) and four bisphenols ((bisphenol A (BPA), bisphenol F (BPF), bisphenol S (BPS), and bisphenol AF (BPAF)) to Tigriopus japonicus was evaluated. TWPs increased the toxicity of BPA and BPF but decreased the toxicity of BPAF. For BPS, there was synergistic toxic effect in the presence of p-TWPs, but slightly antagonistic effect was observed in the presence of a-TWPs. This adsorption of BPAF by TWPs resulted in a reduction of its toxicity to the copepod. A-TWPs could release more Zn than p-TWPs, and the released Zn contributed to the synergistic effect of TWPs and BPA or BPF. The aggregation formed by TWPs in certain sizes (e.g., 90-110 µm) could cause intestinal damage and lipid peroxidation in T. japonicus. The synergistic effect of p-TWPs and BPS might be due to the aggregation size of the binary mixture. The results of the current study will be important to understand the combined toxic effect of TWPs and bisphenols and the potential toxic mechanisms of the binary mixture.

Tool skill impacts the archaeological evidence across technological primates.

The archaeological record offers insights into our evolutionary past by revealing ancient behaviour through stone and fossil remains. Percussive foraging is suggested to be particularly relevant for the emergence of tool-use in our lineage, yet early hominin percussive behaviours remain largely understudied compared to flaked technology. Stone tool-use of extant primates allows the simultaneous investigation of their artefacts and the associated behaviours. This is important for understanding the development of tool surface modification, and crucial for interpreting damage patterns in the archaeological record. Here, we compare the behaviour and the resulting material record across stone tool-using primates. We investigate the relationship of nut-cracking technique and stone tool modification across chimpanzees, capuchins, and long-tailed macaques by conducting standardized field experiments with comparable raw materials. We show that different techniques likely emerged in response to diverse nut hardness, leading to variation in foraging success across species. Our experiments further demonstrate a correlation between techniques and the intensity of visible percussive damage on the tools. Tools used with more precision and efficiency as demonstrated by macaques, show fewer use wear traces. This suggests that some percussive techniques may be less readily identified in the archaeological record.