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Postpartum depression (PPD) affects 174 million women worldwide and is characterized by profound sadness, anxiety, irritability, and debilitating fatigue, which disrupt maternal caregiving and the mother–infant relationship. Limited pharmacological interventions are currently available. Our understanding of the neurobiological pathophysiology of PPD remains incomplete, potentially hindering the development of novel treatment strategies. Recent hypotheses suggest that PPD is driven by a complex interplay of hormonal changes, neurotransmitter imbalances, inflammation, genetic factors, psychosocial stressors, and hypothalamic–pituitary–adrenal (HPA) axis dysregulation. This narrative review examines recent clinical studies on PPD within the past 15 years, emphasizing advancements in neuroimaging findings and blood biomarker detection. Additionally, we summarize recent laboratory work using animal models to mimic PPD, focusing on hormone withdrawal, HPA axis dysfunction, and perinatal stress theories. We also revisit neurobiological results from several brain regions associated with negative emotions, such as the amygdala, prefrontal cortex, hippocampus, and striatum. These insights aim to improve our understanding of PPD's neurobiological mechanisms, guiding future research for better early detection, prevention, and personalized treatment strategies for women affected by PPD and their families. [ABSTRACT FROM AUTHOR]

AbstractBased upon the homogeneous skull model, the skull/brain assembly can be simplified as a homogeneous-shell (HMS)/core structure, in which the exterior shell and interior core represent the skull and brain, respectively. From the blast responses of the spherical shell/core structures calculated via finite element modeling, it is found that the existing homogeneous skull model developed by the well-accepted approach based upon three-point bending tests cannot properly describe the blast response of the skull, modeled as a three-layered sandwich (TLS) shell in the present work, e.g. the average error in the calculated core (brain) pressure is up to ∼30%. Moreover, an innovative approach based upon inverse analysis procedure is then proposed to develop a modified homogeneous skull model, which can give a proper description of the blast response of the skull (a TLS shell), e.g. the average error in the calculated core (brain) pressure is reduced to ∼7%. It is concluded that the well-accepted three-point bending approach cannot develop an effective HMS skull model for studying the blast response of the skull/brain assembly, upon which the model parameter will be overestimated by ∼60%; instead, the innovative approach based upon inverse analysis procedure should be adopted. [ABSTRACT FROM AUTHOR]

Author(s): Weifeng Zhang [1]; Guoxin Cao [1]; Xiaolin Li [1]; Hongyan Zhang [1]; Chong Wang [1]; Quanqing Liu [2]; Xinping Chen [1]; Zhenling Cui [1]; Jianbo Shen [1]; Rongfeng Jiang [...]

Nanoindentation behaviors of zinc oxide (ZnO) nanofilms with different film thicknesses are studied by using both molecular mechanics (MM) simulations and continuum analyses. It is found that there is a significant size effect on the indentation modulus obtained from MM simulations, which is absent in the continuum studies. The indentation modulus increases with the film thickness, and it also increases with the indentation depth; the trend of such a variation also depends on the film thickness. The contributions of the contact size effect, film thickness size effect, and microstructural size effect (surface effect) are elucidated and their couplings are explored. In addition, the substrate effect and nonlinear hyperelastic effect are incorporated to explain the size dependence of elastic indentation behaviors of ZnO nanofilms. [ABSTRACT FROM AUTHOR]

An ab initio analysis based on the density functional theory is carried out to investigate the effects of axial strain and radial pressure on the radial breathing mode (RBM) frequency of individual single-walled carbon nanotubes with armchair and zigzag chiralities. It is found that the RBM frequency is not sensitive to axial tensile strain or small axial compressive strain. When the axial compressive strain exceeds a critical value, the RBM frequency is significantly reduced. On the other hand, the RBM frequency is highly sensitive to the radial pressure; a pressure of 1 GPa can increase the RBM frequency by about 8 cm-1. Under a high radial pressure, the difference between the frequencies of the positive and negative half periods of the RBM vibration sharply increases, which may lead to the separation of the RBM peaks. Very good agreement is found between the present numerical analysis and previous experimental results. [ABSTRACT FROM AUTHOR]