BDNF and pulmonary arterial hypertension: Research in Tongliang, China, found that, compared with a cohort born before the closure of a centrally located coal power plant, a cohort conceived after plant closure had significantly lower cord blood levels of PAH–DNA adducts and higher levels of brain-derived neurotrophic factor (BDNF), a protein important in early brain development (Perera et al. 2008).