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Radiation shielding materials based on composites play a crucial role in safeguarding nuclear-related installations, equipment, and employees from harmful radiation. With the advent of new and challenging nuclear security conditions, the development of radiation-protective materials has undergone significant changes. Thanks to the advancements in science and technology, especially in the field of nanomaterials technology, it is now possible to produce radiation protection materials that offer high all-around performance. This article discusses the current research on composite-based radiation shielding materials. It first describes the current state and distribution of radiation shielding studies worldwide. Then, it categorizes and reviews composite-based radiation protection materials, taking into account the study topic and the field's requirements. The three broad categories of composite-based radiation protection materials are polymer-based composites, metal-based composites, and fabric-based composites. Space radiation shielding materials are categorized separately (as a point of reference). The mechanical, thermal, and shielding properties of radiation protection materials are briefly discussed here. In addition, the primary research challenges are outlined along with the research methodologies that academics employ to examine properties and property change trends. Finally, a summary of the properties of the radiation protection materials discussed in the complete paper is provided, followed by an analysis of the current research gaps and potential future paths. [ABSTRACT FROM AUTHOR]

Stellar feedback-driven outflows regulate the stellar formation and chemical enrichment of galaxies, yet the underlying dependence of mass outflow rate on galaxy properties remains largely unknown. We develop a simple yet comprehensive non-equilibrium chemical evolution model (NE-CEM) to constrain the mass-loading factor η of outflows using the metallicity-stellar mass–SFR relation observed by Sloan Digital Sky Survey (SDSS) at z  = 0. Our NE-CEM predicts the chemical enrichment by explicitly tracking both the histories of star formation and mass-loading. After exploring the eagle simulation, we discover a compact yet flexible model that accurately describes the average star formation histories of galaxies. Applying a novel method of chemically measuring η to eagle , we find η can be parametrized by its dependence on stellar mass and specific SFR as |$\log \eta \propto M_*^{\alpha }s{\mathrm{SFR}}^{\beta }$|⁠ , with α = − 0.12 and β = 0.32 in eagle. Our chemically inferred η agrees remarkably well with the kinematic measurements by Mitchell et al. After extensive tests with eagle , we apply an NE-CEM Bayesian analysis to the SDSS data, yielding a tight constraint of |$\log (\eta /0.631) = 0.731{\pm }0.002\times (M_*/10^{9.5}\, \mathrm{M}_{\odot })^{-0.222\pm 0.004} (s{\mathrm{SFR}}/10^{-9.5}\, \mathrm{yr}^{-1})^{0.078\pm 0.003}$|⁠ , in good agreement with the down-the-barrel measurements. Our best-fitting NE-CEM not only accurately describes the metallicity-stellar mass–SFR relation at z  = 0, but also successfully reproduce the so-called 'fundamental metallicity relation' at higher redshifts. Our results reveal that different galaxies form stars and enrich their gas in a non-equilibrium but strikingly coherent fashion across cosmic time. [ABSTRACT FROM AUTHOR]

Hippocampal neurogenesis-related structural damage, particularly that leading to defective adult cognitive function, is considered an important risk factor for neurodegenerative and psychiatric diseases. Normal differentiation of neurons and glial cells during development is crucial in neurogenesis, which is particularly sensitive to the environmental toxicant methylmercury (MeHg). However, the exact effects of MeHg on hippocampal neural stem cell (hNSC) differentiation during puberty remain unknown. This study investigates whether MeHg exposure induces changes in hippocampal neurogenesis and whether these changes underlie cognitive defects in puberty. A rat model of methylmercury chloride (MeHgCl) exposure (0.4 mg/kg/day, PND 5-PND 33, 28 days) was established, and the Morris water maze was used to assess cognitive function. Primary hNSCs from hippocampal tissues of E16-day Sprague-Dawley rats were purified, identified, and cloned. hNSC proliferation and differentiation and the growth and morphology of newly generated neurons were observed by MTT and immunofluorescence assays. MeHg exposure induced defects in spatial learning and memory accompanied by a decrease in number of doublecortin (DCX)-positive cells in the dentate gyrus (DG). DCX is a surrogate marker for newly generated neurons. Proliferation and differentiation of hNSCs significantly decreased in the MeHg-treated groups. MeHg attenuated microtubule-associated protein-2 (MAP-2) expression in neurons and enhanced the glial fibrillary acidic protein (GFAP)-positive cell differentiation of hNSCs, thereby inducing degenerative changes in a dose-dependent manner. Moreover, MeHg induced deficits in hippocampus-dependent spatial learning and memory during adolescence as a consequence of decreased generation of DG neurons. Our findings suggested that MeHg exposure could be a potential risk factor for psychiatric and neurodegenerative diseases. [ABSTRACT FROM AUTHOR]