Abstract Humans and other vertebrates contain two estrogen receptors (ERs), ERα and ERβ, which mediate the physiological actions of three estrogens: estrone (E1), estradiol (E2) and estriol (E3). Of these three estrogens, in vivo , E2 is the strongest transcriptional activator of ERα and ERβ, E1 is next most active, followed by E3. We studied transcriptional activation of human ERα and ERβ by E2, E1 and E3 in African green monkey kidney (COS-7) cells, which we compared with studies of estrogen stimulation of ER transcription in human embryonic kidney (HEK-293) cells. To our surprise, in COS-7 cells, E3 had the lowest half-maximal response (EC50) for human ERα and ERβ than either E2, which was second most active estrogen, or E1. In contrast, for human ERα and ERβ transfected into HEK-293 cells, E2 was the most active estrogen, followed by E1 and E3. Similar results were found in COS-7 cells and HEK-293 cells transfected with elephant shark ERα and ERβ. Thus, under some conditions, E3 is a more active estrogen than either E2 or E1. This suggests that E3 may be a novel physiological ligand for the ER in some mammalian cells, including the placenta, where E3 levels increase substantially during pregnancy. Highlights The response of the estrogen receptor to its ligand varies according to the specific cell type. In HEK-293 cells, the estrogen receptors demonstrate a high degree of sensitivity to E2, while in COS-7 cells, they exhibit a high degree of sensitivity to E3.
Carbon sink services are essential for climate change mitigation, yet their benefits are unevenly distributed across space. High-emission regions often differ from areas with strong ecosystem carbon uptake, creating spatial mismatches among carbon demand, ecological supply, and compensation responsibility. Existing assessments commonly focus on static supply-demand balances or distance-based source-sink relationships, giving insufficient attention to atmospheric transport pathways and cross-regional benefit attribution. To address this gap, this study develops a forward trajectory-based framework for tracing carbon sink benefits and informing fair regional compensation. The framework integrates carbon sink supply-demand assessment, HYSPLIT-based atmospheric trajectory modeling, representative trajectory clustering, flow allocation, payment for ecosystem services, and financial sustainability assessment. Applied to the Qinghai–Tibet Plateau and surrounding regions from 2000 to 2022, the framework identifies the spatial structure, temporal dynamics, and compensation implications of atmosphere-mediated carbon sink service flows. Results show that carbon sink benefit pathways exhibit directional rigidity, extensive weak connectivity, and pronounced flow asymmetry. The regional carbon sink system has shifted from relative independence toward stronger cross-regional coordination, indicating growing interdependence between carbon-deficit and carbon-surplus areas. The estimated compensation structure shows spatial polarization but also signs of convergence over time, with payment scales generally increasing. Financial sustainability assessment suggests that the proposed payment scheme does not create systematic imbalance for either paying or receiving regions. The study provides a spatially explicit decision-support framework for carbon sink attribution, ecological compensation, and regional carbon governance.
Coupling between magnons and phonons provides a promising pathway toward the realization of phononic diodes and other nonreciprocal phononic functionalities. In this work, we theoretically explore how magnon–phonon hybridization influences elementary excitations in collinear antiferromagnets hosting magnetic toroidal moments. By formulating the full magnon–phonon Hamiltonian and performing numerical diagonalization within the framework of linear spin-wave theory for zigzag and honeycomb structures, we show that the presence of Dzyaloshinskii–Moriya interactions or bond-dependent exchange anisotropy induces nonreciprocity not only in magnon branches but also in phonon modes through their hybridization. Furthermore, we find that the magnitude of phonon nonreciprocity is strongly controlled by the strength of the magnon–phonon coupling. Our results provide a microscopic mechanism for engineering nonreciprocal phononic excitations in magnetic materials characterized by magnetic toroidal moments.
