14 research outputs found
Dynamic analysis of a dielectric elastomer-based bistable system
No full textBistable structures, which are capable of oscillating between two stable states, have garnered significant attention and have been applied in many engineering domains due to their nonlinear behaviors. This paper presents for the first time a physical nonlinear bistable structure comprising a circular dielectric elastic membrane (DEM) coupled with four linear springs, enabling the DEM to achieve large deformations with the system oscillating between two stable equilibrium states. The nonlinear dynamics of the proposed bistable system under harmonic excitation is investigated through analytical, experimental, and numerical methods. First, the system structure is introduced and the corresponding dynamic model is established using Euler-Lagrange equations. Subsequently, the restoring forces of the DEM are experimentally measured, and the dynamic behavior of the bistable system is experimentally tested to validate the theoretical model. Furthermore, the dynamic responses of the system under different excitations are fully studied, and the influences of some key system parameters on the system response are analyzed. Research results demonstrate that the proposed structure exhibits bistable behavior under external excitation and the dynamic behavior of the system can be accurately predicted using the derived theoretical model. The proposed bistable structure contains rich dynamic behaviors including periodic motion, period-doubling bifurcations, and chaotic vibrations. The obtained parameters adjusting rules provide guidelines for the control of system's responses, which have potential applications in many fields such as vibration mitigation and energy harvesting
Population clustering of structural brain aging and its association with brain development
No full textAbstract
Structural brain aging has demonstrated strong inter-individual heterogeneity and mirroring patterns with brain development. However, due to the lack of large-scale longitudinal neuroimaging studies, most of the existing research focused on the cross-sectional changes of brain aging. In this investigation, we present a data-driven approach that incorporate both cross-sectional changes and longitudinal trajectories of structural brain aging and identified two brain aging patterns among 37,013 healthy participants from UK Biobank. Participants with accelerated brain aging also demonstrated accelerated biological aging, cognitive decline and increased genetic susceptibilities to major neuropsychiatric disorders. Further, by integrating longitudinal neuroimaging studies from a multi-center adolescent cohort, we validated the “last in, first out” mirroring hypothesis and identified brain regions with manifested mirroring patterns between brain aging and brain development. Genomic analyses revealed risk loci and genes contributing to accelerated brain aging and delayed brain development, providing molecular basis for elucidating the biological mechanisms underlying brain aging and related disorders
Investigating grey matter volumetric trajectories through the lifespan at the individual level
No full textAbstract Adolescents exhibit remarkable heterogeneity in the structural architecture of brain development. However, due to limited large-scale longitudinal neuroimaging studies, existing research has largely focused on population averages, and the neurobiological basis underlying individual heterogeneity remains poorly understood. Here we identify, using the IMAGEN adolescent cohort followed up over 9 years (14–23 y), three groups of adolescents characterized by distinct developmental patterns of whole-brain gray matter volume (GMV). Group 1 show continuously decreasing GMV associated with higher neurocognitive performances than the other two groups during adolescence. Group 2 exhibit a slower rate of GMV decrease and lower neurocognitive performances compared with Group 1, which was associated with epigenetic differences and greater environmental burden. Group 3 show increasing GMV and lower baseline neurocognitive performances due to a genetic variation. Using the UK Biobank, we show these differences may be attenuated in mid-to-late adulthood. Our study reveals clusters of adolescent neurodevelopment based on GMV and the potential long-term impact
Gene-environment interactions in the influence of maternal education on adolescent neurodevelopment using ABCD study
No full textMaternal education was strongly correlated with adolescent brain morphology, cognitive performances, and mental health. However, the molecular basis for the effects of maternal education on the structural neurodevelopment remains unknown. Here, we conducted gene-environment–wide interaction study using the Adolescent Brain Cognitive Development cohort. Seven genomic loci with significant gene-environment interactions (G×E) on regional gray matter volumes were identified, with enriched biological functions related to metabolic process, inflammatory process, and synaptic plasticity. Additionally, genetic overlapping results with behavioral and disease-related phenotypes indicated shared biological mechanism between maternal education modified neurodevelopment and related behavioral traits. Finally, by decomposing the multidimensional components of maternal education, we found that socioeconomic status, rather than family environment, played a more important role in modifying the genetic effects on neurodevelopment. In summary, our study provided analytical evidence for G×E effects regarding adolescent neurodevelopment and explored potential biological mechanisms as well as social mechanisms through which maternal education could modify the genetic effects on regional brain development.The interplay between gene and maternal education on adolescent brain volumes was studied in both biological and social contexts.Maternal education was strongly correlated with adolescent brain morphology, cognitive performances, and mental health. However, the molecular basis for the effects of maternal education on the structural neurodevelopment remains unknown. Here, we conducted gene-environment–wide interaction study using the Adolescent Brain Cognitive Development cohort. Seven genomic loci with significant gene-environment interactions (G×E) on regional gray matter volumes were identified, with enriched biological functions related to metabolic process, inflammatory process, and synaptic plasticity. Additionally, genetic overlapping results with behavioral and disease-related phenotypes indicated shared biological mechanism between maternal education modified neurodevelopment and related behavioral traits. Finally, by decomposing the multidimensional components of maternal education, we found that socioeconomic status, rather than family environment, played a more important role in modifying the genetic effects on neurodevelopment. In summary, our study provided analytical evidence for G×E effects regarding adolescent neurodevelopment and explored potential biological mechanisms as well as social mechanisms through which maternal education could modify the genetic effects on regional brain development.The interplay between gene and maternal education on adolescent brain volumes was studied in both biological and social contexts
Population clustering of structural brain aging and its association with brain development
No full textStructural brain aging has demonstrated strong inter-individual heterogeneity and mirroring patterns with brain development. However, due to the lack of large-scale longitudinal neuroimaging studies, most of the existing research focused on the cross-sectional changes of brain aging. In this investigation, we present a data-driven approach that incorporate both cross-sectional changes and longitudinal trajectories of structural brain aging and identified two brain aging patterns among 37,013 healthy participants from UK Biobank. Participants with accelerated brain aging also demonstrated accelerated biological aging, cognitive decline and increased genetic susceptibilities to major neuropsychiatric disorders. Further, by integrating longitudinal neuroimaging studies from a multi-center adolescent cohort, we validated the ‘last in, first out’ mirroring hypothesis and identified brain regions with manifested mirroring patterns between brain aging and brain development. Genomic analyses revealed risk loci and genes contributing to accelerated brain aging and delayed brain development, providing molecular basis for elucidating the biological mechanisms underlying brain aging and related disorders.National Natural Science Foundation of China http://dx.doi.org/10.13039/501100001809National Key Research and Development Program of ChinaNational Key Research and Development Program of ChinaShanghai Municipal Science and Technology Major ProjectZJ LabShanghai Center for Brain Science and Brain-Inspired Technology http://dx.doi.org/10.13039/100020441111 project http://dx.doi.org/10.13039/501100013314European Union FP6 Integrated Project IMAGENHorizon 2020 ERC Advanced Grant 'STRATIFY'Human Brain ProjectHuman Brain ProjectMedical Research Council Grant 'c-VEDA'National Institutes of Health http://dx.doi.org/10.13039/100000002National Institute for Health Research (NIHR) Biomedical Research Centre at South London and Maudsley NHS Foundation Trust and King's College LondonDeutsche Forschungsgemeinschaft http://dx.doi.org/10.13039/501100001659Medical Research Foundation and Medical Research CouncilNational Institutes of Health http://dx.doi.org/10.13039/100000002National Institutes of Health http://dx.doi.org/10.13039/100000002ANREranet NeuronFondation de France http://dx.doi.org/10.13039/501100004431Fondation pour la Recherche Médicale http://dx.doi.org/10.13039/501100002915Mission Interministérielle de Lutte-contre-les-Drogues-et-les-Conduites-Addictives http://dx.doi.org/10.13039/501100011000Assistance-Publique-Hôpitaux-de-Paris and INSERMParis Sud University IDEX 2012Fondation de l'Avenir http://dx.doi.org/10.13039/100007380Fédération pour la Recherche sur le Cerveau http://dx.doi.org/10.13039/501100006424National Institutes of Health, Science Foundation IrelandNSFC http://dx.doi.org/10.13039/501100001809environMENTALBundesministeriumfür Bildung und ForschungBundesministeriumfür Bildung und ForschungForschungsnetz AERIALForschungsnetz AERIALForschungsnetz IMAC-MindDeutsche Forschungsgemeinschaft http://dx.doi.org/10.13039/501100001659Deutsche Forschungsgemeinschaft http://dx.doi.org/10.13039/501100001659Deutsche Forschungsgemeinschaft http://dx.doi.org/10.13039/501100001659Medical Research Foundation and Medical Research CouncilNational Institutes of Health http://dx.doi.org/10.13039/100000002Erane
COVID-19 transmission in Mainland China is associated with temperature and humidity: A time-series analysis
No full textCOVID-19 has become a pandemic. The influence of meteorological factors on the transmission and spread of COVID-19 if of interest. This study sought to examine the associations of daily average temperature (AT) and relative humidity (ARH) with the daily count of COVID-19 cases in 30 Chinese provinces (in Hubei from December 1, 2019 to February 11, 2020 and in other provinces from January 20, 2020 to Februarys 11, 2020). A Generalized Additive Model (GAM) was fitted to quantify the province-specific associations between meteorological variables and the daily cases of COVID-19 during the study periods. In the model, the 14-day exponential moving averages (EMAs) of AT and ARH, and their interaction were included with time trend and health-seeking behavior adjusted. Their spatial distributions were visualized. AT and ARH showed significantly negative associations with COVID-19 with a significant interaction between them (0.04, 95% confidence interval: 0.004-0.07) in Hubei. Every 1°C increase in the AT led to a decrease in the daily confirmed cases by 36% to 57% when ARH was in the range from 67% to 85.5%. Every 1% increase in ARH led to a decrease in the daily confirmed cases by 11% to 22% when AT was in the range from 5.04°C to 8.2°C. However, these associations were not consistent throughout Mainland China
Meteorological conditions are heterogeneous factors for COVID-19 risk in China
No full textWhether meteorological factors influence COVID-19 transmission is an issue of major public health concern, but available evidence remains unclear and limited for several reasons, including the use of report date which can lag date of symptom onset by a considerable period. We aimed to generate reliable and robust evidence of this relationship based on date of onset of symptoms. We evaluated important meteorological factors associated with daily COVID-19 counts and effective reproduction number (Rt) in China using a two-stage approach with overdispersed generalized additive models and random-effects meta-analysis. Spatial heterogeneity and stratified analyses by sex and age groups were quantified and potential effect modification was analyzed. Nationwide, there was no evidence that temperature and relative humidity affected COVID-19 incidence and Rt. However, there were heterogeneous impacts on COVID-19 risk across different regions. Importantly, there was a negative association between relative humidity and COVID-19 incidence in Central China: a 1% increase in relative humidity was associated with a 3.92% (95% CI, 1.98% to 5.82%) decrease in daily counts. Older population appeared to be more sensitive to meteorological conditions, but there was no obvious difference between sexes. Linear relationships were found between meteorological variables and COVID-19 incidence. Sensitivity analysis confirmed the robustness of the association and the results based on report date were biased. Meteorological factors play heterogenous roles on COVID-19 transmission, increasing the possibility of seasonality and suggesting the epidemic is far from over. Considering potential climatic associations, we should maintain, not ease, current control measures and surveillance
Uncovering Multi-Omics Profiles of Population Heterogeneity:A Cluster-Based Bayesian Approach
No full textUnderstanding the heterogeneous nature of genetic effects is critical for advancing our knowledge of the genetic architecture of complex traits and developing personalized management strategies. However, existing methods often rely on pre-specified modifying variables to model this heterogeneity, limiting their ability to capture effects driven by complex or unobserved factors. Here, we propose MOCHA (Multi-Omics Clustering for Heterogeneous Association), a novel Bayesian analytical paradigm that identifies latent population subgroups with distinct genetic effects directly from multi-omics data, without requiring a priori variable specification. Extensive simulations confirm that MOCHA accurately identifies the underlying clustering structure, demonstrates superior performance in identifying and ranking features with cluster-specific effects, and provides reliable parameter estimates. Applying MOCHA to genomic and transcriptomic data from the IMAGEN study, we identified two distinct neurodevelopmental clusters associated with adolescent inhibitory control. Post-hoc characterization of these clusters provided novel insights into the mechanisms of brain plasticity, demonstrating the method's practical utility and interpretability.</p
Investigating grey matter volumetric trajectories through the lifespan at the individual level
No full textAdolescents exhibit remarkable heterogeneity in the structural architecture of brain development. However, due to limited large-scale longitudinal neuroimaging studies, existing research has largely focused on population averages, and the neurobiological basis underlying individual heterogeneity remains poorly understood. Here we identify, using the IMAGEN adolescent cohort followed up over 9 years (14-23 y), three groups of adolescents characterized by distinct developmental patterns of whole-brain gray matter volume (GMV). Group 1 show continuously decreasing GMV associated with higher neurocognitive performances than the other two groups during adolescence. Group 2 exhibit a slower rate of GMV decrease and lower neurocognitive performances compared with Group 1, which was associated with epigenetic differences and greater environmental burden. Group 3 show increasing GMV and lower baseline neurocognitive performances due to a genetic variation. Using the UK Biobank, we show these differences may be attenuated in mid-to-late adulthood. Our study reveals clusters of adolescent neurodevelopment based on GMV and the potential long-term impact.</p
DataSheet_1_Spatial architecture of regulatory T-cells correlates with disease progression in patients with nasopharyngeal cancer.docx
No full textPurposeThis study aims to investigate the prognostic value of composition and spatial architecture of tumor-infiltrating lymphocytes (TILs) as well as PDL1 expression on TILs subpopulations in nasopharyngeal carcinoma (NPC).MethodsA total of 121 patients with NPC were included and divided into two groups: favorable (n = 68) and unfavorable (n = 53). The archived tumor tissues of the included patients were retrieved, and a tissue microarray was constructed. The density and spatial distribution of TILs infiltration were analyzed using the multiplex fluorescent immunohistochemistry staining for CD3, CD4, CD8, Foxp3, cytokeratin (CK), PDL1, and 4′,6-diamidino-2-phenylindole (DAPI). The infiltration density of TILs subpopulations and PDL1 expression were compared between the two groups. The Gcross function was calculated to quantify the relative proximity of any two types of cells. The Cox proportional hazards regression model was used to identify factors associated with overall survival (OS) and disease-free survival (DFS).ResultsThe densities of regulatory T-cells (Tregs), effector T-cells (Teffs), PDL1+ Tregs, and PDL1+ Teffs were significantly higher in patients with unfavorable outcomes. PDL1 expression on tumor cells (TCs) or overall TILs was not associated with survival. Multivariate analysis revealed that higher PDL1+ Tregs infiltration density was independently associated with inferior OS and DFS, whereas Tregs infiltration density was only a prognostic marker for DFS. Spatial analysis revealed that unfavorable group had significantly stronger Tregs and PDL1+ Tregs engagement in the proximity of TCs and cytotoxic T lymphocyte (CTLs). Gcross analysis further revealed that Tregs and PDL1+ Tregs were more likely to colocalize with CTLs. Moreover, increased GTC : Treg (Tregs engagement surrounding TCs) and GCTL : PDL1+ Treg were identified as independent factors correlated with poor outcomes.ConclusionTILs have a diverse infiltrating pattern and spatial distribution in NPC. Increased infiltration of Tregs, particularly PDL1+ Tregs, as well as their proximity to TCs and CTLs, correlates with unfavorable outcomes, implying the significance of intercellular immune regulation in mediating disease progression.</p
