Suchergebnisse

AbstractDust events are concerning due to their potential to cause environmental pollution and health issues by carrying numerous particles from various regions. However, the risks of airborne bacteria from dust have not yet been thoroughly investigated. This study aimed to reveal the particle size distribution, antibiotic resistance, microbial community structure, and diversity of airborne bacteria by using culture methods, and assess the potential health risks by calculating the dose expectation $$(\overline{d })$$

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, daily short-term intake (STI), and Hazard Index (HI) during an extreme dust event in urban Beijing (China). Airborne bacteria were sampled before, during, and the day after a severe dust event in March 2021 in Beijing using the six-stage impactor. The major findings were as follows: (1) airborne bacterial concentration increased during the dust event, and inhalable bacteria account for 67.93%. The Hazard Index (HI) of cultivable and inhalable airborne bacteria in men, women, and children exposed to dust events was up to 1.42 and 1.54 times higher than that in individuals who were not exposed, respectively. HI was 1.52 times higher in children than in men when exposed to the dust event. (2) The percentage of Gram-positive bacteria (GPB) resistant to different antibiotics was altered. The abundance of ciprofloxacin-resistant bacteria increased by 24.51%, while that of clindamycin-resistant bacteria decreased by 34.64%. The $$\overline{d }$$

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, STI, and HI of antibiotic-resistant bacteria per breath for men, women, and children after the dust event were 14 times greater than those before the dust event. (3) The diversity of airborne bacteria increased throughout the dust event. Opportunistic bacteria were found after the dust event. From a health perspective, airborne bacteria during extreme dust events should be further studied for their sources, changes, human exposure, and so forth. Government-scale measures are necessary to control dust dissemination.
Graphical Abstract

Magnetic Weyl semimetals are a newly discovered class of topological materials that may serve as a platform for exotic phenomena, such as axion insulators or the quantum anomalous Hall effect. Here, we use angle-resolved photoelectron spectroscopy and ab initio calculations to discover Weyl cones in CoS2, a ferromagnet with pyrite structure that has been long studied as a candidate for half-metallicity, which makes it an attractive material for spintronic devices. We directly observe the topological Fermi arc surface states that link the Weyl nodes, which will influence the performance of CoS2 as a spin injector by modifying its spin polarization at interfaces. In addition, we directly observe a minority-spin bulk electron pocket in the corner of the Brillouin zone, which proves that CoS2 cannot be a true half-metal. ; This work was supported by NSF through the Princeton Center for Complex Materials, a Materials Research Science and Engineering Center DMR-1420541, by Princeton University through the Princeton Catalysis Initiative, and by the Gordon and Betty Moore Foundation through grant GBMF9064 to L.M.S. F.d.J. acknowledges funding from the Spanish MCI/AEI through grant no. PGC2018-101988-B-C21. M.G.V. and F.J. acknowledge funding from the Basque Government through grant PIBA 2019-81. M.G.V. and I.R. acknowledge the Spanish Ministerio de Ciencia e Innovacion (grant number PID2019-109905GB-C21). N.B.M.S. was supported by Microsoft. A.B. acknowledges financial support from the Spanish Ministry of Science and Innovation (PID2019-105488GB-I00). The work of S.S. was supported by the Swiss National Science Foundation under grant no. 159690. D.P. acknowledges the support from the Chinese Scholarship Council. J.A.K. acknowledges support by the Swiss National Science Foundation (SNF-Grant no. 200021_165910). ; Peer reviewed