Surface-Related Toxicity of Polystyrene Beads to Nematodes and the Role of Food Availability.

Microplastics released into freshwaters from anthropogenic sources settle in the sediments, where they may pose an environmental threat to benthic organisms. However, few studies have considered the ecotoxicological hazard of microplastic particles for nematodes, one of the most abundant taxa of the benthic meiofauna. This study investigated the toxic effects of polystyrene (PS) beads (0.1-10.0 µm) and the underlying mechanisms thereof on the reproduction of the nematode Caenorhabditis elegans. The observed effect of the PS beads on the nematodes correlated well with the total surface area of the beads per volume, with a 50% inhibition of reproduction at 55.4 ± 12.9 cm2/mL, independent of the bead size. The adverse effects were not explained by styrene monomers leaching from the beads because chemical activities of styrene in PS suspensions were well below the toxic levels. However, the observed effects could be related to the bead material because the same-sized silica (SiO2) beads had considerably less impact, probably due to their higher specific density. PS and SiO2 beads affected the food availability of C. elegans, with greater effects by the PS beads. Our results demonstrate the importance of including indirect food web effects in studies of the ecological risks posed by microplastics.

Broad-spectrum non-toxic antiviral nanoparticles with a virucidal inhibition mechanism.

Viral infections kill millions yearly. Available antiviral drugs are virus-specific and active against a limited panel of human pathogens. There are broad-spectrum substances that prevent the first step of virus-cell interaction by mimicking heparan sulfate proteoglycans (HSPG), the highly conserved target of viral attachment ligands (VALs). The reversible binding mechanism prevents their use as a drug, because, upon dilution, the inhibition is lost. Known VALs are made of closely packed repeating units, but the aforementioned substances are able to bind only a few of them. We designed antiviral nanoparticles with long and flexible linkers mimicking HSPG, allowing for effective viral association with a binding that we simulate to be strong and multivalent to the VAL repeating units, generating forces (∼190 pN) that eventually lead to irreversible viral deformation. Virucidal assays, electron microscopy images, and molecular dynamics simulations support the proposed mechanism.  These particles show no cytotoxicity, and in vitro nanomolar irreversible activity against herpes simplex virus (HSV), human papilloma virus, respiratory syncytial virus (RSV), dengue and lenti virus. They are active ex vivo in human cervicovaginal histocultures infected by HSV-2 and in vivo in mice infected with RSV.

Autistic adults perceive and experience laughter differently to non-autistic adults.

Human interaction is immersed in laughter; though genuine and posed laughter are acoustically distinct, they are both crucial socio-emotional signals. In this novel study, autistic and non-autistic adults explicitly rated the affective properties of genuine and posed laughter. Additionally, we explored whether their self-reported everyday experiences with laughter differ. Both groups could differentiate between these two types of laughter. However, autistic adults rated posed laughter as more authentic and emotionally arousing than non-autistic adults, perceiving it to be similar to genuine laughter. Autistic adults reported laughing less, deriving less enjoyment from laughter, and experiencing difficulty in understanding the social meaning of other people's laughter compared to non-autistic people. Despite these differences, autistic adults reported using laughter socially as often as non-autistic adults, leveraging it to mediate social contexts. Our findings suggest that autistic adults show subtle differences in their perception of laughter, which may be associated with their struggles in comprehending the social meaning of laughter, as well as their diminished frequency and enjoyment of laughter in everyday scenarios. By combining experimental evidence with first-person experiences, this study suggests that autistic adults likely employ different strategies to understand laughter in everyday contexts, potentially leaving them socially vulnerable in communication.

Development of a novel tool to investigate human laughter behaviour and experience.

We present a questionnaire exploring everyday laughter experience. We developed a 30-item questionnaire in English and collected data on an English-speaking sample (N = 823). Based on Principal Component Analysis (PCA), we identified four dimensions which accounted for variations in people's experiences of laughter: laughter frequency ('Frequency'), social usage of laughter ('Usage'), understanding of other people's laughter ('Understanding'), and feelings towards laughter ('Liking'). Reliability and validity of the LPPQ were assessed. To explore potential similarities and differences based on culture and language, we collected data with Mandarin Chinese-speaking population (N = 574). A PCA suggested the extraction of the same four dimensions, with some item differences between English and Chinese versions. The Laughter Production and Perception Questionnaire (LPPQ) will advance research into the experience of human laughter, which has a potentially crucial role in everyday life.

Sufentanil versus fentanyl: efficacy and patient satisfaction with intrathecal pain management.

OBJECTIVES: This study compared fentanyl vs. sufentanil in intrathecal pain pumps. H1: both reduce patient subjective pain ratings. H2: sufentanil is more effective than fentanyl. H3: overall satisfaction with pain control is greater with sufentanil. MATERIALS/METHOD: This is an archival study of patients in tertiary pain management (N = 97, mean age = 58.77, standard deviation = 14.88). Pain was measured using the subjective units of discomfort scale. Satisfaction with pain control/relief was measured by asking patients each visit if they are satisfied with pain management and is recorded in a "yes"/ "no" manner. Pain ratings were analyzed with repeated measures analysis of variance and satisfaction was analyzed with chi square. RESULTS/DISCUSSION: Sufentanil was found to be marginally more effective, but both medications controlled a significant degree of variance in pain reduction over time. A significantly greater number of patients maintained on sufentanil were satisfied with care than patients on fentanyl.

Urban Adolescence: The Role of Neighbourhood Greenspace in Mental Well-Being.

Mental health and well-being in adolescence are associated with many short- and long-term outcomes. The evidence suggests that greenspace may play a role in adolescents' mental well-being, but we do not know much about the specifics of this link. In this paper, we investigated the role of other factors in the association. In a cross-sectional study, we investigated the role of neighbourhood greenspace in emotional and behavioural outcomes in 11-year-old urban adolescents participating in the UK Millennium Cohort Study (n = 4,534). We used linear regression models to test for an association of greenspace with self-esteem, happiness, positive mood, negative mood, and antisocial behaviour. We also investigated effect modification/moderation by garden access, physical activity, and perceived area safety. We did not find a main effect of greenspace, but we did find interaction effects. First, in adolescents without a garden, higher levels of greenspace were associated with lower levels of self-esteem and positive mood. Second, in adolescents who reported lower levels of physical activity, higher levels of greenspace were associated with lower levels of negative mood. Third, in adolescents who perceived their areas to be unsafe, higher levels of greenspace were associated with higher levels of antisocial behaviour. Our findings suggest that merely more greenspace in the neighbourhood may not be sufficient to promote the mental well-being of urban adolescents in the UK. However, greenspace does seem to have an influence under certain conditions which should be investigated further in future studies.

Ingestion of microplastics by meiobenthic communities in small-scale microcosm experiments.

Microplastics have been detected in many different environments. Nematodes are a rife meiofaunal taxon and occupy an important trophic position in benthic food webs. Laboratory-based ingestion experiments have demonstrated the susceptibility of single nematode species to microplastic uptake. However, the determinants of ingestion by meiofaunal assemblages, especially those of nematodes, have yet to be fully examined. We therefore conducted a microcosm study in which field-collected freshwater sediment was spiked with fluorescent polystyrene (PS) beads (1.0, 3.0 and 6.0 µm) in concentrations of 103 and 107 PS beads ml-1 and the ingestion by the most dominant indigenous meiofaunal taxa (nematodes, rotifers, chironomids, copepods) was investigated after 2, 4 and 8 days using fluorescence microscopy. In additional small-scale microcosms, PS bead ingestion by nematode assemblages was quantified as a function of feeding type, exposure time (1-10 days), concentration (103, 105, 107 PS beads ml-1) and bead size (0.5, 1.0, 3.0, 6.0 µm). PS beads at 107 beads ml-1 were largely ingested by chironomids and copepods. Exposure time and concentration correlated positively with PS bead ingestion for all taxa. The most relevant size class for ingestion for the majority of meiofaunal taxa was PS beads of 1.0 µm. Nematode communities, especially deposit-feeding species, effectively ingested micropastics from sediment, as >30% of the exposed individuals and 56% of the species ingested 1.0-µm PS beads in <24 h. Ingestion rates were mainly influenced by PS bead size and nematode feeding type/habit, with the exception of a bead concentration of 103 beads ml-1, at which exposure time was also an important factor. Sediment particles reduced microplastic ingestion considerably for all investigated meiobenthic organisms. Our study demonstrates the ability of free-living nematodes communities to readily ingest PS beads of various sizes. If the feeding-type distribution is known, the potential exposure of nematode communities may be predicted.

Rapid ingestion and egestion of spherical microplastics by bacteria-feeding nematodes.

Microplastics, anthropogenically released into freshwaters, settle in sediments, where they are directly ingested by benthic organisms. However, to the best of our knowledge, fine-scale studies of microplastic ingestion and egestion by nematodes, one of the most abundant meiofaunal taxa, are lacking. We therefore conducted a time series of the ingestion and egestion by adult Caenorhabditis elegans and Pristionchus pacificus of 0.5- and 1.0-µm fluorescent polystyrene (PS) beads along with bacteria. The nematodes were exposed to 107 beads ml-1 in aqueous medium for 5 min-24 h and pumping rates of C. elegans were determined. In the egestion study, PS bead egestion was monitored in nematodes with high microplastic body burdens for 5 min-24 h in microplastic-free medium. Ingested beads were detected already within 5 min and up to 203 ± 15 PS beads (1.0 µm; C. elegans) were found after 30 min. Overall, significantly more 1.0-µm than 0.5-µm PS beads were taken up. The distinct feeding behaviors of the two species influenced their PS bead body burdens. Ingested PS beads were almost completely egested within the first 20-40 min in the presence of sufficient food. In C. elegans, 1.0-µm beads were egested less rapidly than 0.5-µm PS beads. Given the rapid ingestion and egestion of the beads, our study demonstrates that the actual amount of ingested and egested microplastics by nematodes in the environment may be several times higher than the microplastic body burdens may imply. However, spherical PS beads did not bioconcentrate in nematodes.

The role of the physical environment in adolescent mental health.

The existing literature suggests an association between the physical environment and mental health but also complex relationships between the social and the physical environment as well as between objective and subjective measures of the environment. In this study, we attempted to explore the role of the residential neighbourhood's physical environment in adolescent mental health, taking this complexity into account. Using data on 3683 ten- to 15-year-olds from England and Wales who participated in Understanding Society, we investigated the role of neighbourhood greenspace and air pollution in adolescent mental health (measured with the Strengths and Difficulties Questionnaire) while controlling for measures of neighbourhood and family socio-economic disadvantage as well as subjective perceptions of social cohesion, crime, safety, and noise in the neighbourhood. In linear regression models, greenspace and air pollution could not predict mental health. However, fear of being a victim of crime was a consistent predictor of mental health and behaviour, indicating the essential role of young people's subjective experience of their neighbourhoods for their mental health and well-being.

Ingestion of microplastics by nematodes depends on feeding strategy and buccal cavity size.

Microplastics are hardly biodegradable and thus accumulate rather than decompose in the environment. Due to sedimentation processes, meiobenthic fauna is exposed to microplastics. Within the meiofauna, nematodes are a very abundant taxon and occupy an important position in benthic food webs by connecting lower and higher trophic levels. However, the key determinants of the uptake of microplastics by freshwater nematodes are still unknown. To investigate the bioaccessibility of microplastics for nematodes, we performed single- and multi-species ingestion experiments in which the ability of seven nematode species (six bacterial and one fungal feeder), diverse in their buccal cavity morphology (1.3-10.5 µm), to ingest fluorescence-labelled polystyrene (PS) beads along with their natural diet was examined. Applied beads sizes (0.5, 1.0, 3.0 and 6.0 µm), exposure time (4, 24 and 72 h) and concentration (3 × 106 PS beads ml-1 and 107 PS beads ml-1) were varied. Ingested beads were localized and quantified via fluorescence microscopy in the nematodes. In contrast to fungal-feeding nematode species with a stylet, bacterial-feeding species ingested 0.5- and 1.0-µm PS beads with up to 249 and 255 beads after 24 h, respectively. Microplastics ≥0.5 µm could only be ingested and transported into the gastrointestinal tract, if the buccal cavities were considerably (>1.3 times) larger than the beads. At concentrations of 107 PS beads ml-1 ingestion rates were influenced by exposure time and PS bead concentration. In case of a known microplastic size distribution in the environment, predictions on the potential ingestion for nematode communities can be made based on the feeding type composition and the size of their buccal cavities.

Error-Related Dynamics of Reaction Time and Frontal Midline Theta Activity in Attention Deficit Hyperactivity Disorder (ADHD) During a Subliminal Motor Priming Task.

Post-error slowing (PES) is an established performance monitoring readout. Several previous studies have found that PES is reduced in children and adolescents with attention-deficit hyperactivity disorder (ADHD). We analyzed reaction time data, along with electroencephalography (EEG) data, from a response priming experiment in children and adolescents with ADHD (N = 28) and typically developing (TD) controls (N = 15) between 10 and 17 years of age. We report dynamic reaction time changes before and after errors: whereas TD controls readjusted their response speed to their individual average speed after committing an error, this reaction time adjustment appeared to be delayed and decreased in ADHD patients. In the EEG, error trials were accompanied by increased frontal midline theta activity, which was attenuated in ADHD compared to TD. We conclude that PES has a different time course rather than being fully absent in ADHD and discuss relationships with our EEG findings and potential implications for performance monitoring in ADHD.

Dynamic cellular uptake of mixed-monolayer protected nanoparticles.

Nanoparticles (NPs) are gaining increasing attention for potential application in medicine; consequently, studying their interaction with cells is of central importance. We found that both ligand arrangement and composition on gold nanoparticles play a crucial role in their cellular internalization. In our previous investigation, we showed that 66-34OT nanoparticles coated with stripe-like domains of hydrophobic (octanethiol, OT, 34%) and hydrophilic (11-mercaptoundecane sulfonate, MUS, 66%) ligands permeated through the cellular lipid bilayer via passive diffusion, in addition to endo-/pino-cytosis. Here, we show an analysis of NP internalization by DC2.4, 3T3, and HeLa cells at two temperatures and multiple time points. We study four NPs that differ in their surface structures and ligand compositions and report on their cellular internalization by intracellular fluorescence quantification. Using confocal laser scanning microscopy we have found that all three cell types internalize the 66-34OT NPs more than particles coated only with MUS, or particles coated with a very similar coating but lacking any detectable ligand shell structure, or 'striped' particles but with a different composition (34-66OT) at multiple data points.