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The Mn-Bi-Te class of compounds are recently discovered topological insulators with broken time-reversal-symmetry, which host unique quantum anomalous Hall and axion insulator states. Their key characteristics are believed to be sufficiently understood by models in a single-particle picture. Here, we apply scanning tunneling microscopy to study the electronic properties of MnBi2Te4 and MnBi4Te7. Unexpectedly, our quasiparticle interference (QPI) results demonstrate that rotational symmetry of the crystal breaks, i.e. a nematic-like pattern arises, in certain energy range but persists in others. Moreover, our data in the presence of an external magnetic field rule out the possibility of the material magnetism as an origin of the C2 symmetric QPI pattern. This study reveals that the interaction in the Mn-Bi-Te class of topological materials may play an essential role in their electronic states, and thus opens a new path for investigating the interplay between wavefunction topology and symmetry breaking phases. [ABSTRACT FROM AUTHOR]

Residual sludge (RS) from a wastewater treatment plant was used to prepare sludge-based biochar (RS-BC) by pyrolysis to treat U(VI)-containing wastewater. The findings revealed that RS-BC had exceptional adsorption performance, with a theoretical maximum adsorption capacity for U(VI) of 455.69 mg g−1. The pseudo-second-order and Langmuir isotherm adsorption models effectively fit the adsorption process, and the thermodynamic parameters confirmed that the adsorption process was endothermic and spontaneous. The adsorption efficiency of U(VI) onto RS-BC exhibited remarkable stability and maintained a notable 90% retention even after five cycles of adsorption and desorption. Spectroscopic analyses revealed that ion exchange and complexation were the main adsorption mechanisms. [ABSTRACT FROM AUTHOR]

Cadmium (Cd) is a common environmental metal. Previous studies indicated that long-term respiratory Cd exposure caused lung injury and airway inflammation. The purpose of this study was to evaluate whether short-term respiratory Cd exposure induces pulmonary ferroptosis and NLRP3 inflammasome activation. Adult C57BL/6J mice were exposed to Cd by inhaling CdCl 2 aerosol (0, 10, or 100 ppm) for 5 days. Serum and lung Fe2+ contents were elevated in Cd-exposed mice. Oxidized AA metabolites, the major oxidized lipids during ferroptosis, were upregulated in Cd-exposed mouse lungs. Pulmonary MDA content and 4-HNE-positive cells were increased in Cd-exposed mice. ACSL4 and COX-2, two lipoxygenases, were upregulated in Cd-exposed mouse lungs. Further analyses found that phosphorylated NF-kB p65 was elevated in Cd-exposed mouse lungs. Innate immune receptor protein NLRP3 and adapter protein ASC were upregulated in Cd-exposed mouse lungs. Caspase-1 was activated and IL-1β and IL-18 were upregulated in Cd-exposed mouse lungs. Fer-1, a specific inhibitor of ferroptosis, attenuated Cd-induced elevation of pulmonary NLRP3 and ASC, caspase-1 activation, and IL-1β and IL-18 upregulation. Finally, mitoquinone (MitoQ), a mitochondria-target antioxidant, suppressed Cd-caused ferroptosis and NLRP3 inflammasome activation. Our results demonstrate that ferroptosis might partially mediate Cd-evoked activation of NLRP3 inflammasome in the lungs. [Display omitted] • Short-term respiratory Cd exposure induces ferroptosis in the lungs. • Respiratory Cd exposure causes activation of pulmonary NLRP3 inflammasome. • Ferroptosis is involved in Cd-evoked pulmonary NLRP3 inflammasome activation. • MitoQ prevents Cd-evoked pulmonary ferroptosis and NLRP3 inflammasome activation. [ABSTRACT FROM AUTHOR]

An earlier study found that respiratory cadmium chloride (CdCl 2) exposure caused COPD-like lung injury. This study aimed to explore whether mitochondrial dysfunction-mediated alveolar epithelial senescence is involved in CdCl 2 -induced COPD-like lung injury. Adult C57BL/6 mice were exposed to CdCl 2 (10 mg/L) aerosol for six months. Beta-galactosidase-positive cells, p21 and p16 were increased in CdCl 2 -exposed mouse lungs. The in vitro experiments showed that γ-H 2 AX was elevated in CdCl 2 -exposed alveolar epithelial cells. The cGAS-STING pathway was activated in CdCl 2 -exposed alveolar epithelial cells and mouse lungs. Cxcl1 , Cxcl9 , Il-10 , Il-1β and Mmp2, several senescence-associated secretory phenotypes (SASP), were upregulated in CdCl 2 -exposed alveolar epithelial cells. Mechanistically, CdCl 2 exposure caused SIRT3 reduction and mitochondrial dysfunction in mouse lungs and alveolar epithelial cells. The in vitro experiment found that Sirt3 overexpression attenuated CdCl 2 -induced alveolar epithelial senescence and SASP. The in vivo experiments showed that Sirt3 gene knockout exacerbated CdCl 2 -induced alveolar epithelial senescence, alveolar structure damage, airway inflammation and pulmonary function decline. NMN, an NAD+ precursor, attenuated CdCl 2 -induced alveolar epithelial senescence and SASP in mouse lungs. Moreover, NMN supplementation prevented CdCl 2 -induced COPD-like alveolar structure damage, epithelial-mesenchymal transition and pulmonary function decline. These results suggest that mitochondrial dysfunction-associated alveolar epithelial senescence is involved in CdCl 2 -induced COPD-like lung injury. [Display omitted] • Long-term Cd exposure induced alveolar epithelial senescence and SASP. • Long-term Cd exposure caused SIRT3 reduction and mitochondrial dysfunction. • Sirt3 overexpression attenuated Cd-induced alveolar epithelial senescence and SASP. • Sirt3 knockout exacerbated Cd-induced senescence and COPD-like lung injury. • NMN alleviated Cd-induced alveolar epithelial senescence and COPD-like lung injury. [ABSTRACT FROM AUTHOR]

Polycrystalline diamond films were demonstrated as good candidates for electron field emitters, and their mechanical/thermal properties should thus be considered for real devices. We utilized ultrafast optical techniques to investigate the phonon dynamics of several polycrystalline diamond films, prepared by microwave plasma enhanced chemical vapor deposition. The mechanical properties (longitudinal acoustic velocity) and thermal conductivities of diamond films were evaluated from the coherent and incoherent phonon dynamics, respectively. Ultrananocrystalline diamond films were grown using a CH4 (2%)/Ar plasma, while microcrystalline diamond films were grown using a CH4 (2%)/H2 plasma. The ultrananocrystalline diamond film (with a grain size of several nanometers) possesses low acoustic velocity (14.5 nm/ps) and low thermal conductivity (3.17 W/m K) compared with other kinds of diamond films. The acoustic velocity of diamond films increased abruptly to nearly the same as that of natural diamond and remained there when the rod-shaped diamond grains were induced due to the incorporation of H2 in the growth plasma (CH4/Ar). The thermal conductivities of the materials increased monotonously with increasing incorporation of H2 in the growth plasma (CH4/Ar). The thermal conductivity of 25.6 W/m K was attained for nanocrystalline diamond films containing spherical diamond grains (with a size of several tens of nanometers). Compared with single crystalline diamond, the low thermal conductivity of polycrystalline films results from phonon scattering at the interfaces of grains and amorphous carbon in the boundary phases. [ABSTRACT FROM AUTHOR]

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