904 research outputs found

    Early social isolation stress increases addiction vulnerability to heroin and alters c-Fos expression in the mesocorticolimbic system

    Get PDF
    Rationale Adverse psychosocial factors during early childhood or adolescence compromise neural structure and brain function, inducing susceptibility for many psychiatric disorders such as substance use disorder. Nevertheless, the mechanisms underlying early life stress-induced addiction vulnerability is still unclear, especially for opioids. Objectives To address this, we used a mouse heroin self-administration model to examine how chronic early social isolation (ESI) stress (5 weeks, beginning at weaning) affects the behavioral and neural responses to heroin during adulthood. Results We found that ESI stress did not alter the acquisition for sucrose or heroin self-administration, nor change the motivation for sucrose on a progressive ratio schedule. However, ESI stress induced an upward shift of heroin dose-response curve in female mice and increased motivation and seeking for heroin in both sexes. Furthermore, we examined the neuronal activity (measured by c-Fos expression) within the key brain regions of the mesocorticolimbic system, including the prelimbic cortex (PrL), infralimbic cortex (IL), nucleus accumbens (NAc) core and shell, caudate putamen, and ventral tegmental area (VTA). We found that ESI stress dampened c-Fos expression in the PrL, IL, and VTA after 14-day forced abstinence, while augmented the neuronal responses to heroin-predictive context and cue in the IL and NAc core. Moreover, ESI stress disrupted the association between c-Fos expression and attempted infusions during heroin-seeking test in the PrL. Conclusions These data indicate that ESI stress leads to increased seeking and motivation for heroin, and this may be associated with distinct changes in neuronal activities in different subregions of the mesocorticolimbic system

    A novel bath lily-like graphene sheet-wrapped nano-Si composite as a high performance anode material for Li-ion batteries

    Get PDF
    A novel bath lily-like graphene sheet-wrapped nano-Si composite synthesized via a simple spray drying process exhibits a high reversible capacity of 1525 mAh g(-1) and superior cycling stability, which could be attributed to a synergistic effect between highly conductive graphene sheets and active nanoparticles in the open nano/micro-structure

    Short-term power generation scheduling rules for cascade hydropower stations based on hybrid algorithm

    Get PDF
    AbstractPower generation dispatching is a large complex system problem with multi-dimensional and nonlinear characteristics. A mathematical model was established based on the principle of reservoir operation. A large quantity of optimal scheduling processes were obtained by calculating the daily runoff process within three typical years, and a large number of simulated daily runoff processes were obtained using the progressive optimality algorithm (POA) in combination with the genetic algorithm (GA). After analyzing the optimal scheduling processes, the corresponding scheduling rules were determined, and the practical formulas were obtained. These rules can make full use of the rolling runoff forecast and carry out the rolling scheduling. Compared with the optimized results, the maximum relative difference of the annual power generation obtained by the scheduling rules is no more than 1%. The effectiveness and practical applicability of the scheduling rules are demonstrated by a case study. This study provides a new perspective for formulating the rules of power generation dispatching

    Preliminary study on the immunology pathogenesis of ocular myasthenia gravis in children

    Get PDF
    AIM: To discuss the role of humoral immunity and cellular immunity in the development of ocular myasthenia gravis in children by analyzing the clinical value of the indices including immunoglobulin, complement and T cell subgroup in peripheral blood. <p>METHODS: The concentrations of serum IgG, IgA, IgM, C3 and C4 in the myasthenia gravis group and the control group were detected by immune compare turbid. The contents of CD3<sup>+</sup>T cell, CD4<sup>+</sup>T cell and CD8<sup>+</sup>T cell were detected by flow cytometry. Data was analyzed by Independent-Sample Test.<p>RESULTS: There were no significant differences in contents of IgA, IgM, CD3<sup>+</sup>T cell, CD8<sup>+</sup>T cell between ocular myasthenia gravis group in children and the control group(<i>P</i>>0.05). The concentrations of serum IgG, C3 and C4 for myasthenia gravis group were lower than those of the control group(<i>P</i><0.05). The content of CD4<sup>+</sup>T cell were higher than those of the control group(<i>P</i><0.05).<p>CONCLUSION: Complement C3, C4 and CD4<sup>+</sup>T cell played an important role in immunology pathogenesis mechanism for ocular myasthenia gravis in children

    Spatial-Temporal Instability of an Inviscid Shear Layer

    Get PDF
    In this work, we explore the transition of absolute instability and convective instability in a compressible inviscid shear layer, through a linear spatial-temporal instability analysis. From linearized governing equations of the shear layer and the ideal-gas equation of state, the dispersion relation for the pressure perturbation was obtained. The eigenvalue problem for the evolution of twodimensional perturbation was solved by means of shooting method. The zero group velocity is obtained by a saddle point method. The absolute/convective instability characteristics of the flow are determined by the temporal growth rate at the saddle point. The absolute/convective nature of the flow instability has strong dependence on the values of the temperature ratio, the velocity ratio, the oblique angle, and number. A parametric study indicates that, for a great value of velocity ratio, the inviscid shear layer can transit to absolute instability. The increase of temperature ratio decreases the absolute growth rate when the temperature ratio is large; the effect of temperature ratio is opposite when the temperature ratio is relatively small. The obliquity of the perturbations would cause the increase of the absolute growth rate. The effect of number is different when the oblique angle is great and small. Besides, the absolute instability boundary is found in the velocity ratio, temperature ratio, and number space

    Spatial-Temporal Instability of an Inviscid Shear Layer

    Get PDF
    In this work, we explore the transition of absolute instability and convective instability in a compressible inviscid shear layer, through a linear spatial-temporal instability analysis. From linearized governing equations of the shear layer and the ideal-gas equation of state, the dispersion relation for the pressure perturbation was obtained. The eigenvalue problem for the evolution of two-dimensional perturbation was solved by means of shooting method. The zero group velocity is obtained by a saddle point method. The absolute/convective instability characteristics of the flow are determined by the temporal growth rate at the saddle point. The absolute/convective nature of the flow instability has strong dependence on the values of the temperature ratio, the velocity ratio, the oblique angle, and M number. A parametric study indicates that, for a great value of velocity ratio, the inviscid shear layer can transit to absolute instability. The increase of temperature ratio decreases the absolute growth rate when the temperature ratio is large; the effect of temperature ratio is opposite when the temperature ratio is relatively small. The obliquity of the perturbations would cause the increase of the absolute growth rate. The effect of M number is different when the oblique angle is great and small. Besides, the absolute instability boundary is found in the velocity ratio, temperature ratio, and M number space

    In situ growth of SnO2 on graphene nanosheets as advanced anode materials for rechargeable lithium batteries

    Get PDF
    Graphene with a single layer of carbon atoms densely packed in a honeycomb crystal lattice is one of attractive materials for the intercalation of lithium ion, but it has low volumetric capacity owing to low tap density. We report a method for in situ growth of SnO2 on graphene nanosheets (SGN) as anode materials for rechargeable lithium batteries. The results indicated that the SnO2 nanoparticles with size in the range of 5-10 nm and a polycrystalline structure are homogeneously supported on graphene nanosheets. The charge and discharge capacities of SGN attained to 1559.7 and 779.7 mAh/g in the first cycle at a current density of 300 mA/g. The specific discharge capacities remained at 620 mAhâ‹…g-1 in the 200th cycle. The SGN exhibits a superior Listorage performance with good cycle life and high capacity
    • …
    corecore