The mortality trends analysis of ischemic heart disease attributed to (PM) 2.5 exposure in China from 1990 to 2019 in APC model

OBJECTIVE

To analyze the mortality trend of ischemic heart disease (IHD) attributed to particulate matter (PM) 2.5 exposure among Chinese populations from 1990 to 2019. To evaluate the influences of cohort, period, and age on long-term of IHD mortality trends.

METHODS

Global burden of disease (GBD) data in 2019 regarding IHD death rate attributed to exposure to (PM) 2.5 in China from 1990 to 2019 were adopted. The age-period-cohort (APC) model based on the R language produced by the National Cancer Institute of the United States was used for statistical analysis to investigate the influences of different ages, periods, and cohorts on IHD death rate attributed to exposure to (PM) 2.5.

RESULTS

The age-standardized death rate of IHD attributed to exposure to ambient (PM) 2.5 in China revealed an uptrend from 1990 to 2019. This increased from 8.63/100,000 in 1990 to 21.31/100,000 in 2019. This was an increase of 1.47%. The age-standardized IHD death rate attributed to exposure to household (PM) 2.5 showed a decreasing trend. This decreased from 19.61/100,000 in 1990 to 8.72/100,000 in 2019. This was a decrease of 0.74%. The results of the APC model indicated that the annual net drift of IHD mortality attributed to exposure to (PM) 2.5 was -0.10%. The annual net drifts of exposure to household and ambient (PM) 2.5 were -4.54% and 3.44%, respectively. The IHD death rate attributed to ambient and household (PM) 2.5 exposure in the same birth cohort enhanced with age. With time, the rate ration (RR) of period effects of IHD mortality attributed to ambient (PM) 2.5 exposure for both male and female showed an upward trend. The RR of period effects of IHD death rate attributed to household (PM) 2.5 exposure suggested a downtrend. In the consecutive birth cohorts, the population in China with a later birth cohort presented a higher risk of IHD death attributed to exposure to ambient (PM) 2.5 and a lower risk of IHD death attributed to household (PM) 2.5 exposure.

CONCLUSIONS

In China for the burden of IHD attributed to exposure to (PM) 2.5, the primary environmental risk was ambient (PM) 2.5 exposure compared to exposure to household PM2.5. IHD exposure to environmental air pollution posed a greater risk to young people.

Passage of exogeneous fine particles from the lung into the brain in humans and animals

Addressing the knowledge gaps regarding the access to and harmful effects of airborne fine particles on the central nervous system is critical. Various exogenous fine particles were found in human cerebrospinal fluids, including commonly found particles and others that have not been reported previously. Animal experiments provided mechanistic explanations and verifications of the translocation of inhaled particles into the brain. Moreover, retention of particles in the brain for longer durations than in other organs was demonstrated through isotope labeling–based biodistribution studies in mice, suggesting possible long-term effects on the brain. This work unravels indications and associations between inhalation and particle transport and adds evidence on the relationship between air pollution and detrimental effects of exogenous particles on the brain.

There are still significant knowledge gaps in understanding the intrusion and retention of exogeneous particles into the central nervous system (CNS). Here, we uncovered various exogeneous fine particles in human cerebrospinal fluids (CSFs) and identified the ambient environmental or occupational exposure sources of these particles, including commonly found particles (e.g., Fe- and Ca-containing ones) and other compositions that have not been reported previously (such as malayaite and anatase TiO₂), by mapping their chemical and structural fingerprints. Furthermore, using mouse and in vitro models, we unveiled a possible translocation pathway of various inhaled fine particles from the lung to the brain through blood circulation (via dedicated biodistribution and mechanistic studies). Importantly, with the aid of isotope labeling, we obtained the retention kinetics of inhaled fine particles in mice, indicating a much slower clearance rate of localized exogenous particles from the brain than from other main metabolic organs. Collectively, our results provide a piece of evidence on the intrusion of exogeneous particles into the CNS and support the association between the inhalation of exogenous particles and their transport into the brain tissues. This work thus provides additional insights for the continued investigation of the adverse effects of air pollution on the brain.

Analyzing Dirac Cone and Phonon Dispersion in Highly Oriented Nanocrystalline Graphene

Chemical vapor deposition (CVD) is one of the most promising growth techniques to scale up the production of monolayer graphene. At present, there are intense efforts to control the orientation of graphene grains during CVD, motivated by the fact that there is a higher probability for oriented grains to achieve seamless merging, forming a large single crystal. However, it is still challenging to produce single-crystal graphene with no grain boundaries over macroscopic length scales, especially when the nucleation density of graphene nuclei is high. Nonetheless, nanocrystalline graphene with highly oriented grains may exhibit single-crystal-like properties. Herein, we investigate the spectroscopic signatures of graphene film containing highly oriented, nanosized grains (20-150 nm) using angle-resolved photoemission spectroscopy (ARPES) and high-resolution electron energy loss spectroscopy (HREELS). The robustness of the Dirac cone, as well as dispersion of its phonons, as a function of graphene's grain size and before and after film coalescence, was investigated. In view of the sensitivity of atomically thin graphene to atmospheric adsorbates and intercalants, ARPES and HREELS were also used to monitor the changes in spectroscopic signatures of the graphene film following exposure to the ambient atmosphere.