Polyhedral Covers of Tree Space

The phylogenetic tree space, introduced by Billera, Holmes, and Vogtmann, is a cone over a simplicial complex. In this short article, we construct this complex from local gluings of classical polytopes, the associahedron and the permutohedron. Its homotopy is also reinterpreted and calculated based on polytope data.Comment: 8 pages, 9 figure

Amphiphilic, Peptide-Modified Core/Shell Microgels

Thermoresponsive poly(N-isopropylacrylamide) (pNIPAm) core/shell particles bearing primary amine groups in either core or shell were prepared via two-stage, free radical precipitation polymerization, using 2-aminoethyl methacrylate (AEMA) as a comonomer. The amine groups were then used to initiate ring-opening polymerization of γ-benzyl L-glutamate N-carboxyanhydride (BLG-NCA), producing poly(γ-benzyl L-glutamate) (PBLG) side chains covalently anchored to the particles. Photon Correlation Spectroscopy (PCS) and 1H NMR were employed to characterize these particles. A shift of phase transition to a lower temperature and an increase in particle des welling volume ratios were observed as a result of grafting hydrophobic PBLG chains to the particles. Further studies by 1H NMR in different solvents indicate that the PBLG chains grafted from the particle shell phase separate on the pNIPAm networks in aqueous media but remain well solvated in DMSO. Together, these results suggest that both core- and shell-grafted architectures can be synthesized with equal ease, and that the particle structure and colloidal behavior can be manipulated by tuning the relative solubility of the network and graft portions of the particle.https://digitalcommons.chapman.edu/sees_books/1004/thumbnail.jp

Underestimated activity-based microplastic intake under scenario-specific exposures

Despite increasing alarms over the health impacts of microplastics (MPs) due to their detection in human organs and feces, precise exposure evaluations remain scarce. To comprehend their risks, there is a distinct need to prioritize quantitive estimates in MP exposome, particularly at the environmentally-realistic level. Here we used a method rooted in real-world MP measurements and activity patterns to determine the daily intake of MPs through inhalation and from ground dust/soil ingestion. We found that nearly 80% of this intake comes from residential sectors, with activity intensity and behavioral types significantly affecting the human MP burden. The data showed a peak in MP exposure for those aged 18–64. When compared to dietary MP intake sources like seafood, salt, and water, we identified a previously underestimated exposure from inhalation and dust/soil ingestion, emphasizing the need for more realistic evaluations that incorporate activity factors. This discovery raises questions about the accuracy of past studies and underscores MP's potential health risks. Moreover, our time-based simulations revealed increased MP intake during the COVID-19 lockdown due to more surface dust ingestion, shedding light on how global health crises may inadvertently elevate MP exposure risks

Economic development and coastal ecosystem change in China

Despite their value, coastal ecosystems are globally threatened by anthropogenic impacts, yet how these impacts are driven by economic development is not well understood. We compiled a multifaceted dataset to quantify coastal trends and examine the role of economic growth in China's coastal degradation since the 1950s. Although China's coastal population growth did not change following the 1978 economic reforms, its coastal economy increased by orders of magnitude. All 15 coastal human impacts examined increased over time, especially after the reforms. Econometric analysis revealed positive relationships between most impacts and GDP across temporal and spatial scales, often lacking dropping thresholds. These relationships generally held when influences of population growth were addressed by analyzing per capita impacts, and when population density was included as explanatory variables. Historical trends in physical and biotic indicators showed that China's coastal ecosystems changed little or slowly between the 1950s and 1978, but have degraded at accelerated rates since 1978. Thus economic growth has been the cause of accelerating human damage to China's coastal ecosystems. China's GDP per capita remains very low. Without strict conservation efforts, continuing economic growth will further degrade China's coastal ecosystems.http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000340593000007&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=8e1609b174ce4e31116a60747a720701Multidisciplinary SciencesSCI(E)[email protected]