| Research Article | | Detection of interstellar 1-cyanopyrene: A four-ring polycyclic aromatic hydrocarbon | | By GABI WENZEL, ILSA R. COOKE, ET AL. | 24 OCT 2024 | | Polycyclic aromatic hydrocarbons (PAHs) are organic molecules containing adjacent aromatic rings. Infrared emission bands show that PAHs are abundant in space, but only a few specific PAHs have been detected in the interstellar medium. We detect 1-cyanopyrene, a cyano-substituted derivative of the related four-ring PAH pyrene, in radio observations of the dense cloud TMC-1 using the Green Bank Telescope. The measured column density of 1-cyanopyrene is … | |
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| Research Article | | Retrotransposons are co-opted to activate hematopoietic stem cells and erythropoiesis | | By JULIA PHAN, BRANDON CHEN, ET AL. | 24 OCT 2024 | | Hematopoietic stem cells (HSCs) and erythropoiesis are activated during pregnancy and after bleeding by the derepression of retrotransposons, including endogenous retroviruses and LINE elements. Retrotransposon transcription activates the innate immune sensors cyclic GMP-AMP synthase (cGAS) and stimulator of interferon (IFN) genes (STING), which induce IFN and IFN-regulated genes in HSCs, increasing HSC division and erythropoiesis. Inhibition of reverse transcriptase or deficiency for cGAS or STING had little or no effect on hematopoiesis in non-pregnant mice but depleted HSCs and erythroid progenitors in pregnant mice, reducing red blood cell counts. Retrotransposons and IFN regulated genes were also induced in mouse HSCs after serial bleeding and in human HSCs during pregnancy. Reverse transcriptase inhibitor use was associated with anemia in pregnant, but not non-pregnant, people suggesting conservation of these mechanisms from mice to humans. | |
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| Research Article | | Dissecting the hydrogen bond network of water: Charge transfer and nuclear quantum effects | | By MISCHA FLÓR, DAVID M. WILKINS, ET AL. | 24 OCT 2024 | | The molecular structure of water is dynamic, with intermolecular (H)-bond interactions being modified by both electronic charge transfer and nuclear quantum effects (NQEs). Electronic charge transfer and NQEs potentially change under acidic / basic conditions, but such details have not been measured. Here, we developed correlated vibrational spectroscopy, a symmetry-based method that distinctively separates interacting from non-interacting molecules in self- and cross-correlation spectra, giving access to previously inaccessible information. We found that OH− donated ~8% more negative charge to the H-bond network of water and H 3O+ accepted ~4% less negative charge from the H-bond network of water. D2O had ~9% more H-bonds compared to H2O, and acidic solutions displayed more dominant NQEs than basic ones. | |
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| Research Article | GROUNDWATER | | Predictions of groundwater PFAS occurrence at drinking water supply depths in the United States | | By ANDREA K. TOKRANOV, KATHERINE M. RANSOM, ET AL. | 24 OCT 2024 | | Per- and polyfluoroalkyl substances (PFAS), known colloquially as “forever chemicals”, have been associated with adverse human health effects and have contaminated drinking water supplies across the United States owing to their long-term and widespread use. People in the United States may unknowingly be drinking water that contains PFAS because of a lack of systematic analysis, particularly in domestic water supplies. We present an extreme gradient boosting model for predicting the occurrence of PFAS in groundwater at the depths of drinking water supply for the conterminous United States. Our model results indicate that 71 to 95 million people in the conterminous United States potentially rely on groundwater with detectable concentrations of PFAS for their drinking-water supplies prior to any treatment. | |
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