Notes

Promoting older people encountering anxiety by way of non-pharmacological surgery.
Nitrogenases utilize Fe-S clusters to reduce N2 to NH3 The large number of Fe sites in their catalytic cofactors has hampered spectroscopic investigations into their electronic structures, mechanisms, and biosyntheses. To facilitate their spectroscopic analysis, we are developing methods for incorporating 57Fe into specific sites of nitrogenase cofactors, and we report herein site-selective 57Fe labeling of the L-cluster-a carbide-containing, [Fe8S9C] precursor to the Mo nitrogenase catalytic cofactor. Treatment of the isolated L-cluster with the chelator ethylenediaminetetraacetate followed by reconstitution with 57Fe2+ results in 57Fe labeling of the terminal Fe sites in high yield and with high selectivity. This protocol enables the generation of L-cluster samples in which either the two terminal or the six belt Fe sites are selectively labeled with 57Fe. Mössbauer spectroscopic analysis of these samples bound to the nitrogenase maturase Azotobacter vinelandii NifX reveals differences in the primary coordination sphere of the terminal Fe sites and that one of the terminal sites of the L-cluster binds to H35 of Av NifX. This work provides molecular-level insights into the electronic structure and biosynthesis of the L-cluster and introduces postbiosynthetic modification as a promising strategy for studies of nitrogenase cofactors.Information manipulation is widespread in today's media environment. Online networks have disrupted the gatekeeping role of traditional media by allowing various actors to influence the public agenda; they have also allowed automated accounts (or bots) to blend with human activity in the flow of information. Here, we assess the impact that bots had on the dissemination of content during two contentious political events that evolved in real time on social media. We focus on events of heightened political tension because they are particularly susceptible to information campaigns designed to mislead or exacerbate conflict. We compare the visibility of bots with human accounts, verified accounts, and mainstream news outlets. Our analyses combine millions of posts from a popular microblogging platform with web-tracking data collected from two different countries and timeframes. We employ tools from network science, natural language processing, and machine learning to analyze the diffusion structure, the content of the messages diffused, and the actors behind those messages as the political events unfolded. We show that verified accounts are significantly more visible than unverified bots in the coverage of the events but also that bots attract more attention than human accounts. Our findings highlight that social media and the web are very different news ecosystems in terms of prevalent news sources and that both humans and bots contribute to generate discrepancy in news visibility with their activity.Noeggerathiales are enigmatic plants that existed during Carboniferous and Permian times, ∼323 to 252 Mya. Although their morphology, diversity, and distribution are well known, their systematic affinity remained enigmatic because their anatomy was unknown. Here, we report from a 298-My-old volcanic ash deposit, an in situ, complete, anatomically preserved noeggerathialean. The plant resolves the group's affinity and places it in a key evolutionary position within the seed plant sister group. Paratingia wuhaia sp. nov. is a small tree producing gymnospermous wood with a crown of pinnate, compound megaphyllous leaves and fertile shoots each with Ω-shaped vascular bundles. The heterosporous (containing both microspores and megaspores), bisporangiate fertile shoots appear cylindrical and cone-like, but their bilateral vasculature demonstrates that they are complex, three-dimensional sporophylls, representing leaf homologs that are unique to Noeggerathiales. The combination of heterospory and gymnospermous wood confirms that Paratingia, and thus the Noeggerathiales, are progymnosperms. Progymnosperms constitute the seed plant stem group, and Paratingia extends their range 60 My, to the end of the Permian. Cladistic analysis resolves the position of the Noeggerathiales as the most derived members of a heterosporous progymnosperm clade that are the seed plant sister group, altering our understanding of the relationships within the seed plant stem lineage and the transition from pteridophytic spore-based reproduction to the seed. Permian Noeggerathiales show that the heterosporous progymnosperm sister group to seed plants diversified alongside the primary radiation of seed plants for ∼110 My, independently evolving sophisticated cone-like fertile organs from modified leaves.Measles virus (MeV) is highly infectious by the respiratory route and remains an important cause of childhood mortality. However, the process by which MeV infection is efficiently established in the respiratory tract is controversial with suggestions that respiratory epithelial cells are not susceptible to infection from the apical mucosal surface. Therefore, it has been hypothesized that infection is initiated in lung macrophages or dendritic cells and that epithelial infection is subsequently established through the basolateral surface by infected lymphocytes. To better understand the process of respiratory tract initiation of MeV infection, primary differentiated respiratory epithelial cell cultures were established from rhesus macaque tracheal and nasal tissues. MRTX-1257 in vivo Infection of these cultures with MeV from the apical surface was more efficient than from the basolateral surface with shedding of viable MeV-producing multinucleated giant cell (MGC) syncytia from the surface. Despite presence of MGCs and infectious virus in supernatant fluids after apical infection, infected cells were not detected in the adherent epithelial sheet and transepithelial electrical resistance was maintained. After infection from the basolateral surface, epithelial damage and large clusters of MeV-positive cells were observed. Treatment with fusion inhibitory peptides showed that MeV production after apical infection was not dependent on infection of the basolateral surface. These results are consistent with the hypothesis that MeV infection is initiated by apical infection of respiratory epithelial cells with subsequent infection of lymphoid tissue and systemic spread.
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