Frontiers A novel risk factor for dementia: chronic microplastic exposure Frontiers Microplastic effects on soil nitrogen storage, nitrogen emissions, and ammonia volatilization in relation to soil health and crop productivity: mechanism and future consideration Incorporation of polylactic acid microplastics into the carbon cycle as a carbon source to remodel the endogenous metabolism of the gut PNAS Frontiers A novel risk factor for dementia: chronic microplastic exposure