Determining factors of physical activity and sedentary behaviour in university students during the COVID-19 pandemic: a longitudinal study

Introduction: Historically, university students demonstrate poor movement behaviours that could negatively impact current and future health. Recent literature has focused on identifying determinants of physical activity (PA) and sedentary behaviour (SB) in this population to inform the development of intervention strategies. However, the COVID-19 pandemic substantially restricted movement behaviours in this population, meaning findings of previous research may no longer be applicable within the current societal context. The present study explored the longitudinal relationships between pre-pandemic psychological, behavioural and anthropometric factors, and the movement behaviours of UK university students nine months following the outbreak of COVID-19. Methods: Mental wellbeing (MWB), perceived stress (PS), body mass index (BMI), SB, and PA were assessed using an online self-report survey in 255 students prior to (October 2019) and nine months following (October 2020) the first confirmed case of COVID-19 in the UK. Path analysis was utilised to test relationships between pre-COVID mental wellbeing, perceived stress and BMI, and movement behaviours during the pandemic. Results: The fit of the path analysis model was good (χ2 = 0.01; CMIN = 0.10, CFI = 1.00, RMSEA = 0.00). Pre-covid MWB and PS positively influenced PA (β = 0.29; β = 0.24; P < 0.01) but not SB (β = -0.10; β = 0.00; P = 0.79) during the pandemic. Additionally, pre-pandemic SB and PA positively influenced SB and PA during the pandemic respectively (SB: β = 0.26; P < 0.01) (PA: β = 0.55; P < 0.01). Pre-pandemic BMI did not influence any measured variable during the pandemic (PA: β = 0.03 and P = 0.29; SB: β = 0.06 and P = 0.56), and there was no mediating effect of PA on SB during the pandemic (β = -0.26; P = 0.14). Conclusion: These findings indicate that pre-covid mental health and movement behaviours had a direct positive influence on PA during the pandemic, but not SB. This longitudinal study demonstrates the influence that prior psychological and behavioural factors have in determining university students’ response to periods of elevated stress and uncertainty, furthering our understanding of determinants of health-related behaviours in students

Macrophage exosomes induce placental inflammatory cytokines: a novel mode of maternal-placental messaging

During pregnancy, the placenta forms the interface between mother and fetus. Highly controlled regulation of trans-placental trafficking is therefore essential for the healthy development of the growing fetus. Extracellular vesicle-mediated transfer of protein and nucleic acids from the human placenta into the maternal circulation is well documented; the possibility that this trafficking is bi-directional has not yet been explored but could affect placental function and impact on the fetus. We hypothesized that the ability of the placenta to respond to maternal inflammatory signals is mediated by the interaction of maternal immune cell exosomes with placental trophoblast. Utilising the BeWo cell line and whole placental explants, we demonstrated that the human placenta internalizes macrophage-derived exosomes in a time- and dose-dependent manner. This uptake was via clathrin-dependent endocytosis. Furthermore, macrophage exosomes induced production of proinflammatory cytokines by the placenta. Taken together, our data demonstrates that exosomes are actively transported into the human placenta and that exosomes from activated immune cells modulate placental cytokine production. This represents a novel mechanism by which immune cells can signal to the placental unit, potentially facilitating responses to maternal inflammation and infection, and thereby preventing harm to the fetus

The Hilbert Series of the One Instanton Moduli Space

The moduli space of k G-instantons on R^4 for a classical gauge group G is known to be given by the Higgs branch of a supersymmetric gauge theory that lives on Dp branes probing D(p + 4) branes in Type II theories. For p = 3, these (3 + 1) dimensional gauge theories have N = 2 supersymmetry and can be represented by quiver diagrams. The F and D term equations coincide with the ADHM construction. The Hilbert series of the moduli spaces of one instanton for classical gauge groups is easy to compute and turns out to take a particularly simple form which is previously unknown. This allows for a G invariant character expansion and hence easily generalisable for exceptional gauge groups, where an ADHM construction is not known. The conjectures for exceptional groups are further checked using some new techniques like sewing relations in Hilbert Series. This is applied to Argyres-Seiberg dualities.Comment: 43 pages, 22 figure

NDE Applications of Radio Wave Emission from Stress and Fracture

It is well-known [1], [2] that when materials are fractured, substantial local electric fields are generated. These fields are capable of accelerating charged particles from the nascent interfaces, giving rise to a class of phenomena known as “exo-emission” or “fracto-emission”. The released “exo-particles”, consisting of electrons, ions, and charged clusters or fragments, can be collected and analyzed directly. Usually, such experiments are performed under conditions of high or ultra-high vacuum. This type of particle emission has been extensively studied previously, most notably by Dickinson and his co-workers [2] — [7]. Except for previous studies of fracturing rock, performed in connection with early-warning detection of earthquakes [8], [9], and the work of Dickinson, little has been done to characterize the radio wave emission that attends material fractures. Furthermore, no previous studies of radio wave emission from the elastically or plastically strained materials have been reported. Early qualitative studies of the visible light and radio wave emission from delaminating layers of adhesively bonded polymers and metals were reported by Derjagun and his co-workers. Emission during deformation suggests itself as a possible method for diagnosing the state of dynamic material strain in situations where contact methods are not feasible or are undesirable. Examples of such potential applications are too numerous to delineate here; they include the detection of high speed particle impacts on spacecraft structures, dynamic test of radioactive, extremely hot or cold structures, and others. We also note that for the elucidation of the detailed mechanism of fracture, radio-wave emission may have advantages over other methods since, unlike acoustic or ultrasonic methods, the speed of propagation of the detected signal is much greater than the speed of the propagating crack-front in the material, so little or no deconvolution is required.</p

Neuroelectric Evidence for Cognitive Association Formation: An Event-Related Potential Investigation

Although many types of learning require associations to be formed, little is known about the brain mechanisms engaged in association formation. In the present study, we measured event-related potentials (ERPs) while participants studied pairs of semantically related words, with each word of a pair presented sequentially. To narrow in on the associative component of the signal, the ERP difference between the first and second words of a pair (Word2-Word1) was derived separately for subsequently recalled and subsequently not-recalled pairs. When the resulting difference waveforms were contrasted, a parietal positivity was observed for subsequently recalled pairs around 460 ms after the word presentation onset, followed by a positive slow wave that lasted until around 845 ms. Together these results suggest that associations formed between semantically related words are correlated with a specific neural signature that is reflected in scalp recordings over the parietal region

Nocodazole Treatment Decreases Expression of Pluripotency Markers Nanog and Oct4 in Human Embryonic Stem Cells

Nocodazole is a known destabiliser of microtubule dynamics and arrests cell-cycle at the G2/M phase. In the context of the human embryonic stem cell (hESC) it is important to understand how this arrest influences the pluripotency of cells. Here we report for the first time the changes in the expression of transcription markers Nanog and Oct4 as well as SSEA-3 and SSEA-4 in human embryonic cells after their treatment with nocodazole. Multivariate permeabilised-cell flow cytometry was applied for characterising the expression of Nanog and Oct4 during different cell cycle phases. Among untreated hESC we detected Nanog-expressing cells, which also expressed Oct4, SSEA-3 and SSEA-4. We also found another population expressing SSEA-4, but without Nanog, Oct4 and SSEA-3 expression. Nocodazole treatment resulted in a decrease of cell population positive for all four markers Nanog, Oct4, SSEA-3, SSEA-4. Nocodazole-mediated cell-cycle arrest was accompanied by higher rate of apoptosis and upregulation of p53. Twenty-four hours after the release from nocodazole block, the cell cycle of hESC normalised, but no increase in the expression of transcription markers Nanog and Oct4 was detected. In addition, the presence of ROCK-2 inhibitor Y-27632 in the medium had no effect on increasing the expression of pluripotency markers Nanog and Oct4 or decreasing apoptosis or the level of p53. The expression of SSEA-3 and SSEA-4 increased in Nanog-positive cells after wash-out of nocodazole in the presence and in the absence of Y-27632. Our data show that in hESC nocodazole reversible blocks cell cycle, which is accompanied by irreversible loss of expression of pluripotency markers Nanog and Oct4

The functional maturation of M cells is dramatically reduced in the Peyer's patches of aged mice

The transcytosis of antigens across the follicle-associated epithelium (FAE) of Peyer's patches by microfold cells (M cells) is important for the induction of efficient immune responses to mucosal antigens. The mucosal immune response is compromised by ageing, but effects on M cells were unknown. We show that M-cell density in the FAE of aged mice was dramatically reduced. As a consequence, aged Peyer's patches were significantly deficient in their ability to transcytose particulate lumenal antigen across the FAE. Ageing specifically impaired the expression of Spi-B and the downstream functional maturation of M cells. Ageing also dramatically impaired C-C motif chemokine ligand 20 expression by the FAE. As a consequence, fewer B cells were attracted towards the FAE, potentially reducing their ability to promote M-cell maturation. Our study demonstrates that ageing dramatically impedes the functional maturation of M cells, revealing an important ageing-related defect in the mucosal immune system's ability to sample lumenal antigens

Comparison of dust released from sanding conventional and nanoparticle-doped wall and wood coatings

Introduction of engineered nanoparticles (ENPs) into traditional surface coatings (e.g., paints, lacquers, fillers) may result in new exposures to both workers and consumers and possibly also a new risk to their health. During finishing and renovation, such products may also be a substantial source of exposure to ENPs or aggregates thereof. This study investigates the particle size distributions (5.6 nm–19.8 μm) and the total number of dust particles generated during sanding of ENP-doped paints, lacquers, and fillers as compared to their conventional counterparts. In all products, the dust emissions from sanding were found to consist of five size modes: three modes under 1 μm and two modes around 1 and 2 μm. Corrected for the emission from the sanding machine, the sanding dust, was dominated by 100–300 nm size particles, whereas the mass and surface area spectra were dominated by the micrometer modes. Adding ENPs to the studied products only vaguely affected the geometric mean diameters of the particle modes in the sanding dust when compared to their reference products. However, we observed considerable differences in the number concentrations in the different size modes, but still without revealing a clear effect of ENPs on dust emissions from sanding

Toll-like receptor 2 expression is decreased on alveolar macrophages in cigarette smokers and COPD patients

BACKROUND: Cigarette smoke exposure including biologically active lipopolysaccharide (LPS) in the particulate phase of cigarette smoke induces activation of alveolar macrophages (AM) and alveolar epithelial cells leading to production of inflammatory mediators. This represents a crucial mechanism in the pathogenesis of chronic obstructive pulmonary disease (COPD). Respiratory pathogens are a major cause of exacerbations leading to recurrent cycles of injury and repair. The interaction between pathogen-associated molecular patterns and the host is mediated by pattern recognition receptors (PRR's). In the present study we characterized the expression of Toll-like receptor (TLR)- 2, TLR4 and CD14 on human AM compared to autologous monocytes obtained from patients with COPD, healthy smokers and non-smokers. METHODS: The study population consisted of 14 COPD patients without evidence for acute exacerbation, 10 healthy smokers and 17 healthy non-smokers stratified according to age. The expression of TLR2, TLR4 and CD14 surface molecules on human AM compared to autologous monocytes was assessed ex vivo using FACS analysis. In situ hybridization was performed on bronchoalveolar lavage (BAL) cells by application of the new developed HOPE-fixative. RESULTS: The expression of TLR2, TLR4 and CD14 on AM from COPD patients, smokers and non-smokers was reduced as compared to autologous monocytes. Comparing AM we detected a reduced expression of TLR2 in COPD patients and smokers. In addition TLR2 mRNA and protein expression was increased after LPS stimulation on non-smokers AM in contrast to smokers and COPD patients. CONCLUSION: Our data suggest a smoke related change in the phenotype of AM's and the cellular response to microbial stimulation which may be associated with impairment of host defenses in the lower respiratory tract