Reproductive and germ-cell mutagenic effects of poly-and perfluoroalkyl substances (PFAS) to Caenorhabditis elegans after multigenerational exposure.

Per- and polyfluoroalkyl substances (PFAS) are a class of globally ubiquitous persistent organic pollutants (POPs). The developmental and reproductive toxicity of PFAS have attracted considerable attention. However, the influence of PFAS exposure on genomic stability of germ cells remains unexplored. In this study, we evaluated long-term reproductive toxicity of environmentally relevant levels of four long-chain PFAS compounds: perfluorooctanoic acid (PFOA, C8), perfluorononanoic acid (PFNA, C9), perfluorodecanoic acid (PFDA, C10), and perfluorooctanesulfonic acid (PFOS, C8), and examined their germ-cell mutagenicity in Caenorhabditis elegans. Our findings reveal that multigenerational exposure to PFAS exhibited minor impacts on development and reproduction of worms. Among all tested PFAS, PFNA significantly increased mutation frequencies of progeny by preferentially inducing T:A â†’ C:G substitutions and small indels within repetitive regions. Further analysis of mutation spectra uncovered elevated frequencies of microhomology-mediated deletions and large deletions in PFOA-treated worms, indicating its potential activity in eliciting DNA double-strand breaks. This study provides the first comparative analysis of the genome-wide mutational profile of PFAS compounds, underscoring the importance of assessing germ-cell mutagenic actions of long-chain PFAS.

Multigenerational effects and mutagenicity of three flame retardants on germ cells in Caenorhabditis elegans.

Flame retardants (FRs) have raised public concerns because of their environmental persistence and negative impacts on human health. Recent evidence has revealed that many FRs exhibit reproductive toxicities and transgenerational impacts, whereas the toxic effects of FRs on germ cells remain barely explored. Here we investigated the multigenerational effects of three flame retardants (TBBPA, TCEP and TCPP) on germ cell development in Caenorhabditis elegans, and examined the germ cell mutagenicity of these FRs by using whole genome sequencing. Parental exposure to three FRs markedly increased germ cell apoptosis, and impeded oogenesis in F1-F6 offspring. In addition, the double-increased mutation frequencies observed in progeny genomes uncover the mutagenic actions of FRs on germ cells. Analysis of mutation spectra revealed that these FRs predominantly induced point mutations at A:T base pairs, whereas both small and large indels were almost unaffected. These results revealed the long-term effects of FRs on development and genomic stability of germ cells, which may pose risks to environmental organisms and human reproductive health. Taken together, our findings suggest that germ cell mutagenicity should be carefully examined for the environmental risk assessment of FRs and other emerging pollutants.

Fusion of electromagnetic world and digital world through information metasurface: an interview with Tie Jun Cui.

Metasurfaces consist of subwavelength artificial elements (also called meta-atoms) arranged in a two-dimensional fashion. Through careful design of these elements, the metasurfaces can control the amplitude, phase, frequency, and polarization of electromagnetic (EM) waves. Information metasurfaces extend this concept by characterizing the meta-atoms in a digital manner, integrating functionalities for information processing. The information metasurfaces can simultaneously manipulate the EM waves in reprogrammable ways and modulate the digital information in real time, making the fusion of the EM world and digital world. The information metasurfaces have found diverse applications in wireless communications, intelligent sensing and imaging, intelligent computing, and internet of things (IoT). Prof. Tie Jun Cui is affiliated with Southeast University in Nanjing, China, where he serves as the Director of the State Key Laboratory of Millimeter Waves. He is a prominent researcher in the field of metamaterial, metasurface, and computational electromagnetics. He has proposed the concepts, and made systematic studies, of digital coding metasurfaces and programmable metasurfaces, and established the system of information metasurfaces, building a direct link between the electromagnetic world and digital world. NSR spoke to Professor Cui on the recent advancement and the prospects of information metasurfaces.

BICM-ID scheme for clipped DCO-OFDM in visible light communications.

Visible light communication (VLC) is recommended for indoor transmissions in 5G network, whereby DC-biased optical orthogonal frequency division multiplexing (DCO-OFDM) is adopted to eliminate the inter-symbol interference (ISI) but suffers from considerable performance loss induced by clipping distortion. In this paper, bit-interleaved coded modulation with iterative demapping and decoding (BICM-ID) scheme for clipped DCO-OFDM is investigated to enhance the performance of VLC systems. In order to further mitigate the clipping distortions, a novel soft demapping criterion is proposed, and a simplified demapping algorithm is developed to reduce the complexity of the proposed criterion. Simulation results illustrate that the enhanced demapping algorithm achieves a significant performance gain.