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Experimental and theoretical analysis of a spontaneous Leidenfrost transitioning phenomenon
No full textThis study offers a thorough experimental and theoretical analysis of a unique droplet behavior known as spontaneous Leidenfrost transitioning (SLT). This phenomenon occurs between stable transitional boiling and Leidenfrost rebound. By creating a novel experimental platform that allows for spatial observations of hydrodynamic and thermodynamic behaviors, we uncover significant insights into SLT. Our experimental observations indicate that the occurrence of SLT is independent of the Bond number. However, a higher temperature is necessary to trigger SLT as the Bond number increases. Initially, SLT expands but narrows with rising Weber number, with larger Bond numbers exhibiting earlier narrowing due to intensified thermal-induced instability. Furthermore, enhanced surface smoothness and hydrophilicity are unfavorable for SLT initiation. We identify three distinct phases of SLT: intensive boiling, consecutive levitation, and stable Leidenfrost rebound. By analyzing three hydrodynamic parameters during the second phase, we propose a mechanism describing the evolution of SLT at increasing temperatures. Our investigations into phase transitions reveal that rapid retraction and the formation of a central lift force drive the transition from intensive boiling to consecutive levitation. We also establish a theoretical model to describe the subsequent transition into stable Leidenfrost rebound, which validates the case-sensitive nature of the proposed mechanism while successfully linking it to droplet deformation and heat transfer behavior. These findings provide valuable insights into the underexplored droplet behaviors between two well-known regimes, enhancing the understanding of transitional boiling instability and the transition from stable transitional boiling to Leidenfrost rebound
Maternal controlling parenting and youth-perceived mother-child attachment mediate the association between maternal adverse childhood experiences and adolescent behavioral difficulties
Full text linkBackground: Maternal adverse childhood experiences (ACEs) are risk factors for increased mental health difficulties. However, intergenerational transmission mechanisms between maternal ACEs and adolescent behavioral difficulties are poorly understood. This study examined the mediating effects of maternal controlling parenting and youth-perceived mother-child attachment on the association between maternal ACEs and adolescent internalizing and externalizing behaviors.Methods: Data were from the nationally representative Growing Up in Scotland birth cohort 1. Analyses focused on 2943 adolescents aged 14–15 at sweep 10 but utilized information from the entire cohort (N = 5719) to minimize parameter bias. Linear regression analyses were used to examine the strength of predictors (maternal ACEs, maternal controlling parenting, youth-perceived mother-child attachment) on adolescent behavioral difficulties levels. Mediating effects of maternal controlling parenting and youth-perceived mother-child attachment were assessed using serial mediation models.Results: Regression analysis indicated maternal ACEs were associated with adolescent behavioral difficulties. Serial mediation models indicated a consistent indirect effect of maternal ACEs on adolescent internalizing and externalizing behaviors, through maternal controlling parenting and youth-perceived mother-child attachment.Conclusions: This study indicates that both maternal controlling parenting and youth-perceived mother-child attachment are mechanisms mediating the effect of maternal ACEs on adolescent internalizing and externalizing behaviors. Understanding the interactive impact of both maternal and child factors may improve policy and programming to ameliorate intergenerational consequences of maternal ACEs on youth mental health
The longitudinal properties of the HCR-20:A systematic review
Full text linkA key objective in forensic mental healthcare is to manage risk of interpersonal violence. The use of structured professional judgement (SPJ) tools is intended to guide assessment of risk, and appraisal of treatment response. As such, measurement of violence risk is important in determining when patients are ready to progress to less restrictive environments. One of the most widely-used instruments for assessing risk of violence is the Historic-Clinical-Risk Management Scale – 20 (HCR-20). While the HCR-20 is commonly employed as a repeated measure, it remains unclear whether its scores are sensitive to changes in risk over time. This systematic review identified twelve studies investigating the measure's longitudinal properties, and examined whether the evidence suggests that it is sensitive to change. The included studies were all of reasonable quality, but with varying designs and timeframes. Findings suggest that the Clinical, Risk Management, and total scores of the HCR-20 typically decrease over time and concur with other SPJ measures. However, recorded decreases in scores tend to be very small, raising the question of their clinical significance. There was little evidence to suggest that a decrease in HCR-20 scores over time is associated with a decrease in the likelihood of subsequent violent recidivism. The results were highly heterogeneous, and factors contributing to this variation are discussed.</p
Predicting words across languages depends on language context:Evidence from visual world eye-tracking
Full text linkThere is good evidence that monolingual comprehenders can predict the form of upcoming words, and also that bilinguals often activate words from both languages in parallel during bottom-up language comprehension. But it is unclear whether bilinguals predict the form of upcoming words in the language that they are not hearing, and whether such predictions depend on whether or not they have recently encountered that language. We investigated these questions in two visual-world eye-tracking experiments by asking whether Mandarin Chinese (L1)-English (L2) bilinguals pre-activate Mandarin phonological representations of predictable words during English comprehension. Participants heard English sentences containing a highly predictable word while viewing a display. They fixated more on a competitor object whose Mandarin name was a homophone of the Mandarin translation of the predictable word than an unrelated object when both languages were used (Experiment 2) but not when just English was used (Experiment 1). Our findings suggest that bilinguals predict across languages when both languages are contextually relevant but not otherwise
Stillbirth in intrahepatic cholestasis of pregnancy and timing of severely elevated bile acid concentrations: an observational cohort study
No full textUltrasound-driven formation of defects and radicals in contact-electro-catalysis: a DFT and AIMD investigation
No full textThis study reveals the critical chemical and physical roles of ultrasound in enhancing contact-electro-catalysis (CEC), using the methane (CH4) oxidation process as a model system. By integrating density functional theory (DFT), ab initio molecular dynamics (AIMD), and targeted experiments, we demonstrate for the first time that ultrasonic treatment significantly modifies the solid material’s (i.e. CEC catalyst) surface chemistry and morphology, leading to enhanced catalytic performance. FTIR and Raman spectroscopy analyses reveal distinct molecular-level changes in the tested solid material (i.e. fluorinated ethylene propylene (FEP)) following ultrasonication, specifically the formation of C–H bonds, aligning closely with theoretical spectra predictions. Additionally, ultrasound induces substantial physical alterations, tripling the surface roughness of FEP, and significantly elevating fluoride ion concentrations in the surrounding solution, indicating pronounced C–F bond cleavage. AIMD simulations further elucidate that ultrasound-generated radicals initiate homogenous catalytic pathways by cleaving C–H bonds in CH4, identifying this as a critical mechanistic step previously unclarified. Those induced structural defects in FEP could also simultaneously enhance heterogeneous catalytic activity. Our findings establish a comprehensive mechanistic framework that resolves prior ambiguities in ultrasound-assisted CEC processes, offering robust theoretical and experimental foundations for advancing CEC catalytic efficiency and guiding future CEC catalyst development
Cerebral ischaemic stroke results in altered mucosal antibody responses and host-commensal microbiota interactions
No full textStroke is a devastating neurological event with a high risk of mortality that results in long-term sequalae that extend beyond the central nervous system. Notably these include gastrointestinal dysfunction and altered composition of the commensal microbiota in both patients and mouse models, which have been suggested to contribute to secondary infection and poor clinical outcomes following stroke. Strikingly, changes in commensal microbial community composition occur rapidly following stroke and correlate with disease severity. Despite these observations, the underpinning mechanisms that drive perturbation of the microbiota post-stroke remain poorly understood. The gastrointestinal tract is home to a complex network of tissue-resident immune cells that maintain homeostatic interactions with commensal microbes and prevent bacterial-driven inflammation. Here we demonstrate mice subjected to ischaemic stroke exhibit alterations in the intestinal immune system, most notably in class switched germinal centre B cells and the production of Immunoglobulin A (IgA) - a major effector response against commensal microbes. Mice lacking secretory antibodies, including IgA, exhibited a partial reversion of stroke-induced changes in microbiota composition. Together these findings demonstrate stroke is associated with dysregulation of antibody producing immune responses, which may in part explain changes in the intestinal microbiota. A mechanistic understanding of the immunological basis of stroke-associated pathologies in the periphery may open new avenues to manage the secondary complications and long-term prognosis of patients suffering from neurological disease.</p
Ultrafast crosslinking, strongly adhesive de novo protein hydrogels promote cartilage regeneration
Full text linkOsteoarthritis (OA) is a prevalent degenerative joint disease and the leading cause of chronic pain and disability, affecting millions of people worldwide. In the early stages, shallow cartilage lesions serve as the primary pathological driver, leading to progressive cartilage deterioration and the development of OA. These lesions are characterized by irregular shape and depth, with an inherent anti-adhesive extracellular matrix (ECM), and a poor niche for tissue regeneration, currently lacking effective clinical interventions. Despite extensive efforts, few tissue engineering-based therapies simultaneously address both the demands of robust adhesion to host tissue, support for cell adhesion, and promotion of regeneration for partial-thickness cartilage defects. Here, we report a de novo engineered protein adhesive hydrogel that displays ultrafast gelation, robust tissue adhesion, and maintains chondrocyte phenotype. Tyrosine, lysine, and RGD motifs were precisely encoded into the protein backbone by genetic engineering to enable visible light-triggered covalent bonding, electrostatic interactions with negatively charged cartilage ECM, and enhanced cell adhesion. Molecular weight was tailored by extending monomer repeats to further improve the mechanical performance. Importantly, this genetically engineered protein hydrogel demonstrated ultrafast gelation (< 2 s), high adhesive strength (90.8 ± 1.8 kPa), excellent biocompatibility in vitro and in vivo, and supported chondrogenic maintenance. These hydrogels also promoted hyaline-like cartilage matrix regeneration in the partial-thickness cartilage defect rabbit model. Overall, our findings present a bottom-up protein engineering strategy for developing multifunctional adhesive hydrogels, offering a promising translational platform for musculoskeletal disease treatment, in particular cartilage repair
Learning disabilities and adolescent suicidal ideation:Findings from the z-proso cohort study
Full text linkObjectiveTo investigate suicidal ideation among adolescents with learning disabilities and examine whether learning disabilities and a range of risk and protective factors assessed at age 13 are associated with suicidal ideation at age 15.MethodsLongitudinal data were drawn from a youth population-based cohort (Zurich Project on the Social Development from Childhood to Adulthood [z-proso]; N = 1675). Modified Poisson regression was used to estimate the relative risk of suicidal ideation at age 15, with learning disabilities along with the other variables as predictors. An additional model included an interaction term between learning disabilities and anxiety/depression symptoms to test whether the association between anxiety/depression and suicidal ideation varied by learning disability status. Average marginal effects were used to estimate absolute differences in predicted probabilities between groups.ResultsAdolescents with learning disabilities reported significantly higher rates of suicidal ideation (32.5 %) and self-injury (18.4 %) compared to peers without learning disabilities. They showed elevated levels of most risk factors and lower levels of protective factors. Significant predictors of increased relative risk of suicidal ideation included female sex, anxiety/depression symptoms, bullying experiences, and learning disabilities, the latter associated with a 40.2 % higher risk (RR = 1.402, 95 % CI = [1.070, 1.387]). Average marginal effects indicated that anxiety/depression significantly increased suicidal ideation risk among adolescents without learning disabilities but not among those with learning disabilities.ConclusionsFindings suggest that learning disabilities are a significant risk factor for adolescent suicidal ideation, highlighting the need for early identification, tailored assessment, and targeted prevention strategies
Exploiting cellulose:xyloglucan endotransglucosylase activity — exploring novel acceptor substrates carrying valuable ‘cargoes’
Full text linkHetero-trans-β-glucanase (HTG) is an Equisetum plant enzyme that covalently grafts cellulose (donor substrate) to xyloglucan heptasaccharide (XXXG; Xyl3.Glc4 as acceptor substrate). Commercial exploitation of this technology requires bulk XXXG production. Novel acceptor substrates bearing two or more XXXG moieties could potentially cross-link cellulose chains. We explored bulk XXXG production, the synthesis of novel (including multimeric) XXXG conjugates and novel coloured derivatives, and explored new activators of HTG action. Commercial tamarind gum (crude xyloglucan) was digested with xyloglucan endo-glucanase, producing mixed xyloglucan oligosaccharides, which were then enzymically de-galactosylated to XXXG. Sequential application of the two enzymes proved more reliable than simultaneous. XXXG was reductively aminated with 1,2-diaminoethane (DAE), generating conjugates with the constitution XXXGol1–4-DAE. In some cases, [14C]DAE was used, generating radiolabelled conjugates. The products were characterised by ninhydrin staining, thin-layer chromatographic mobility and electrophoretically determined charge:mass ratio. All DAE conjugates of XXXGol proved satisfactory acceptor substrates for HTG. We also reductively aminated XXXG with toluidine blue O (TB), generating coloured conjugates (XXXGol1-2-TB) that were likewise HTG acceptor substrates, allowing visualisation of this and other XXXG reactions on paper substrata. Furthermore, we discovered hydrophilic neutral polymers, e.g. polyvinylalcohol and polyethyleneglycol (but not a polyanion or polycation), that were highly effective activators of HTG action on cellulose — alternatives to the conventionally used bovine serum albumin. Casein and various food-grade plant protein preparations were also effective. In conclusion, this work opens the way to utilising Equisetum HTG to chemically modify cellulose, with exciting potential commercial benefits. <br/
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