846 research outputs found

    Study reveals effect of aluminum on saturation moment of Fe-Ni alloys

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    Study of saturation magnetization, important in the investigation of the electronic structure of alloys, reveals the effect of aluminum on the saturation moments of iron-nickel alloys. The saturation magnetizations were extrapolated to the absolute zero of temperature for calculating average atomic moments

    Exercise Selectively Mobilises Skin-Homing Effector CD8+ T Cells and Natural Killer Cells into Peripheral Blood.

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    Introduction: Acute exercise induces a transient mobilisation of lymphocyes into peripheral blood that is largely comprised of CD8+ T cells and natural killer (NK) cells. The magnitude of this response is dependent on the differentiation status of these lymphocyte subsets, thus cells with a capacity to initiate rapid effector function (i.e., cytokine secretion and target killing) exhibit the largest changes in response to exercise. It is hypothesised that the effector cells preferentially mobilised into the bloodstream have high tissue-migrating potential, however, the origin of these cells, and their potential homing destination(s) following exercise has not been established in humans. Accordingly, this study investigated whether CD8+ and NK cell subsets expressing the cutaneous lymphocte antigen (CLA) – a molecule expressed on skin-associated memory lymphocytes (≤ 20% CD8+ T cells and ≤ 50%NK cells) that binds to endothelial cell leukocyte adhesion molecule 1 (ELAM-1) – were selectively mobilised in response to acute exercise. Methods: Ten healthy males (mean ± SD age: 22 ± 3 yrs) completed two different exercise sessions: high-intensity continuous cycling (CC; 85% at HRPeak for 30 mins) and high-intensity interval training (HIIT; 90% of HRpeak 10 x 1 min repetitions with 1 min rest intervals). Blood was taken before, immediately- and 30 min post-exercise for cryo-preservation of peripheral blood mononuclear cells. CD8+ subsets were classified into naive (NA; CD45RA+CCR7+), central memory (CM; CD45RA−CCR7+), effector-memory (EM; CD45RA−CCR7−) and CD45RA- expressing effector-memory cells (EMRA; CD45RA+CCR7−). In parallel, CD56bright ‘regulatory’ and CD56dim ‘cytotoxic’ NK subsets were identified using CD56 and CD16. Lymphocyte subpopulations were examined for CLA expression. Results: The number of CLA+CD8+ cells increased in response to both exercise modes. This observation was driven by a preferential mobilisation of effector-memory CLA+CD8+ T cells, as shown by the percentage change in cell number from baseline to exercise: EMRA (CC 244%, HIIT 86%) \u3e EM (CC 142%, HIIT 75%) \u3e CM (CC 104%, HIIT 51%) \u3e naive (CC 82%, HIIT 34%). Within the NK cell pool, CLA+CD56dim cells (CC 520%, HIIT 326%) were mobilised to a greater extent than CLA+CD56bright cells (CC 180%, HIIT 129%). 30-min post-exercise, there was a reduction in the number of CLA+ cells compared to pre-exercise values. Conclusion: This is the first study to demonstrate a selective mobilisation of skin-homing lymphocytes during exercise, suggesting that exercise redistributes effector cells to peripheral tissue, contributing to immune-surveillance

    Cyclists in shared bus lanes: could there be unrecognised impacts on bus journey times?

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    This paper contributes to debates around improving the modelling of cycles, through an exploratory case study of bus–cycle interactions in London. This case study examines undocumented delays to buses caused by high volumes of cyclists in bus lanes. It has generally been assumed that cyclists do not noticeably delay buses in shared lanes. However, in many contexts where cyclists routinely share bus lanes, cyclist numbers have historically been low. In some such places, bus lanes are now seeing very high volumes of cyclists, far above those previously studied. This may have implications for bus – and cycle – journey times, but traditionally traffic modelling has not represented the effects of such interactions well. With some manipulation of parameters taken from models of other cities, the model described here demonstrates that cycles can cause significant delays to buses in shared lanes, at high cycling volumes. These delays are likely to become substantially larger if London's cycling demographic becomes more diverse, because cyclist speeds will decline. Hence bus journey time benefits may derive from separating cycles from buses, where cycle flows are high. The project also suggests that microsimulation modelling software, as typically used, remains problematic for representing cyclists

    Non-invasive MRI quantification of cerebrospinal fluid dynamics in amyotrophic lateral sclerosis patients.

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    BACKGROUND: Developing novel therapeutic agents to treat amyotrophic lateral sclerosis (ALS) has been difficult due to multifactorial pathophysiologic processes at work. Intrathecal drug administration shows promise due to close proximity of cerebrospinal fluid (CSF) to affected tissues. Development of effective intrathecal pharmaceuticals will rely on accurate models of how drugs are dispersed in the CSF. Therefore, a method to quantify these dynamics and a characterization of differences across disease states is needed. METHODS: Complete intrathecal 3D CSF geometry and CSF flow velocities at six axial locations in the spinal canal were collected by T2-weighted and phase-contrast MRI, respectively. Scans were completed for eight people with ALS and ten healthy controls. Manual segmentation of the spinal subarachnoid space was performed and coupled with an interpolated model of CSF flow within the spinal canal. Geometric and hydrodynamic parameters were then generated at 1 mm slice intervals along the entire spine. Temporal analysis of the waveform spectral content and feature points was also completed. RESULTS: Comparison of ALS and control groups revealed a reduction in CSF flow magnitude and increased flow propagation velocities in the ALS cohort. Other differences in spectral harmonic content and geometric comparisons may support an overall decrease in intrathecal compliance in the ALS group. Notably, there was a high degree of variability between cases, with one ALS patient displaying nearly zero CSF flow along the entire spinal canal. CONCLUSION: While our sample size limits statistical confidence about the differences observed in this study, it was possible to measure and quantify inter-individual and cohort variability in a non-invasive manner. Our study also shows the potential for MRI based measurements of CSF geometry and flow to provide information about the hydrodynamic environment of the spinal subarachnoid space. These dynamics may be studied further to understand the behavior of CSF solute transport in healthy and diseased states

    Ab initio study of the volume dependence of dynamical and thermodynamical properties of silicon

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    Motivated by the negative thermal expansion observed for silicon between 20 K and 120 K, we present first an ab initio study of the volume dependence of interatomic force constants, phonon frequencies of TA(X) and TA(L) modes, and of the associated mode Gruneisen parameters. The influence of successive nearest neighbors shells is analysed. Analytical formulas, taking into account interactions up to second nearest neighbors, are developped for phonon frequencies of TA(X) and TA(L) modes and the corresponding mode Gruneisen parameters. We also analyze the volume and pressure dependence of various thermodynamic properties (specific heat, bulk modulus, thermal expansion), and point out the effect of the negative mode Gruneisen parameters of the acoustic branches on these properties. Finally, we present the evolution of the mean square atomic displacement and of the atomic temperature factor with the temperature for different volumes, for which the anomalous effects are even greater.Comment: 24 pages, Revtex 3.0, 11 figures, accepted for publication in Phys. Rev.

    Generalisation of Social Communication Skills by Autistic Children During Play-Based Assessments Across Home, School and an Unfamiliar Research Setting

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    \ua9 The Author(s) 2024.We investigated autistic children’s generalisation of social communication over time across three settings during a play-based assessment with different adults and explore the potential moderating effects on generalisation of age, nonverbal IQ and level of restricted and repetitive behaviours. The social communication abilities of 248 autistic children (2–11 years, 21% female, 22% single parent, 60% white) from three UK sites were assessed from 1984 video interactions in three contexts with three different interaction partners (parent/home, teaching assistant/school, researcher/clinic) at baseline, midpoint (+ 7m) and endpoint (+ 12m) within the Paediatric Autism Communication Trial-Generalised (PACT-G), a parent-mediated social communication intervention. Children’s midpoint social communication at home generalised to school at midpoint and to clinic at endpoint. Generalisation was stronger from home to school and clinic than school to home and clinic. Generalisation was not moderated by age, nonverbal IQ or restricted and repetitive behaviour. Broader child development did not explain the pattern of results. The current study is the largest study to date to explore generalisation with autistic children and provides novel insight into their generalisation of social communication skills. Further research is needed to gain a more comprehensive understanding of facilitators of generalisation across settings and interaction partners in order to develop targeted strategies for interventions to enhance outcomes for young autistic children

    Metamorphosis in the Cirripede Crustacean Balanus amphitrite

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    Stalked and acorn barnacles (Cirripedia Thoracica) have a complex life cycle that includes a free-swimming nauplius larva, a cypris larva and a permanently attached sessile juvenile and adult barnacle. The barnacle cyprid is among the most highly specialized of marine invertebrate larvae and its settlement biology has been intensively studied. By contrast, surprisingly few papers have dealt with the critical series of metamorphic events from cementation of the cyprid to the substratum until the appearance of a suspension feeding juvenile. This metamorphosis is both ontogenetically complex and critical to the survival of the barnacle. Here we use video microscopy to present a timeline and description of morphological events from settled cyprid to juvenile barnacle in the model species Balanus amphitrite, representing an important step towards both a broader understanding of the settlement ecology of this species and a platform for studying the factors that control its metamorphosis. Metamorphosis in B. amphitrite involves a complex sequence of events: cementation, epidermis separation from the cypris cuticle, degeneration of cypris musculature, rotation of the thorax inside the mantle cavity, building of the juvenile musculature, contraction of antennular muscles, raising of the body, shedding of the cypris cuticle, shell plate and basis formation and, possibly, a further moult to become a suspension feeding barnacle. We compare these events with developmental information from other barnacle species and discuss them in the framework of barnacle settlement ecology

    Rudimentary signs of immunosenescence in <em>Cytomegalovirus</em>-seropositive healthy young adults

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    Ageing is associated with a decline in immune competence termed immunosenescence. In the elderly, this process results in an accumulation of differentiated ‘effector’ phenotype memory T cells, predominantly driven by Cytomegalovirus (CMV) infection. Here, we asked whether CMV also drives immunity towards a senescent profile in healthy young adults. One hundred and fifty-eight individuals (mean ± SD; age 21 ± 3 years, body mass index 22.7 ± 2.7 kg m2) were assessed for CMV serostatus, the numbers/proportions of CD4+ and CD8+ late differentiated/effector memory cells (i.e. CD27−CD28−/CD45RA+), plasma interleukin-6 (IL-6) and antibody responses to an in vivo antigen challenge (half-dose influenza vaccine). Thirty percent (48/158) of participants were CMV+. A higher lymphocyte and CD8+ count (both p < 0.01) and a lower CD4/CD8 ratio (p < 0.03) were observed in CMV+ people. Eight percent (4/58) of CMV+ individuals exhibited a CD4/CD8 ratio <1.0, whereas no CMV− donor showed an inverted ratio (p < 0.001). The numbers of CD4+ and CD8+CD27−CD28−/CD45RA+ cells were ~ fourfold higher in CMV+ people (p < 0.001). Plasma IL-6 was higher in CMV+ donors (p < 0.05) and showed a positive association with the numbers of CD8+CD28− cells (p < 0.03). Finally, there was a significant negative correlation between vaccine-induced antibody responses to the A/Brisbane influenza strain and CMV-specific immunoglobulin G titres (p < 0.05). This reduced vaccination response was associated with greater numbers of total CD8+ and CD4+ and CD8+CD27−CD28−/CD45RA+ cells (p < 0.05). This study observed marked changes in the immune profile of young adults infected with CMV, suggesting that this virus may underlie rudimentary aspects of immunosenescence even in a chronologically young population
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