The impact of PM2.5 on lung function in adults with asthma

OBJECTIVE: To conduct a systematic review of the literature and assess the effect of PM2.5 (particulate matter with diameter &lt;2.5 μm) exposure on lung function in adults with asthma.METHODS: We searched all literature published between 1 January 2010 and 26 March 2019 in the EMBASE, PubMed, Cochrane Central Library, Chinese National Knowledge Infrastructure (CNKI), Wanfang and Chinese Biomedical Literature (CBM) databases. The studies were assessed for analytic methods, risk of bias and results of statistical analysis.RESULTS: The selected studies all had a low or moderate risk of bias. Overall, PM2.5 exposure was positively associated with a decrease in forced expiratory volume in 1 sec (FEV1)/forced vital capacity (FVC) in adults with asthma (standardised mean difference 0.20, 95% CI 0.02–0.38; P = 0.03).CONCLUSION: We observed a negative correlation between PM2.5 exposure and FEV1/FVC in patients with asthma. Our meta-analysis provides evidence suggesting that PM2.5 is a risk factor for acute asthma exacerbation in adults.</jats:p

Charge state-dependent symmetry breaking of atomic defects in transition metal dichalcogenides

The functionality of atomic quantum emitters is intrinsically linked to their host lattice coordination. Structural distortions that spontaneously break the lattice symmetry strongly impact their optical emission properties and spin-photon interface. Here we report on the direct imaging of charge state-dependent symmetry breaking of two prototypical atomic quantum emitters in mono- and bilayer MoS2 by scanning tunneling microscopy (STM) and non-contact atomic force microscopy (nc-AFM). By changing the built-in substrate chemical potential, different charge states of sulfur vacancies (VacS) and substitutional rhenium dopants (ReMo) can be stabilized. Vac as well as Re and Re exhibit local lattice distortions and symmetry-broken defect orbitals attributed to a Jahn-Teller effect (JTE) and pseudo-JTE, respectively. By mapping the electronic and geometric structure of single point defects, we disentangle the effects of spatial averaging, charge multistability, configurational dynamics, and external perturbations that often mask the presence of local symmetry breaking