The nucleation processes of polyethylene under quiescent and shear flow conditions are comparatively studied with all-atom molecular dynamics simulations. Under both conditions, nucleation is demonstrated to be a two-step process, which, however, proceeds via different intermediate orders. Quiescent nucleation is assisted by local order structures, while flow-induced nucleation is promoted by density fluctuation, which is a coupling effect of conformational and orientational orderings. Flow drives the transformation from flexible chains to conformational ordered segments and circumvents the entropic penalty, which is the most peculiar and rate-limited step in polymer crystallization. This work suggests that the acceleration of the nucleation rate in orders of magnitude by flow is mainly attributed to the different kinetics pathway via conformational/orientational ordering-density fluctuation-nucleation.
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http://dx.doi.org/10.1063/1.5054273 | DOI Listing |
Langmuir
January 2025
Key Laboratory of Electromagnetic Processing of Materials (Ministry of Education), Northeastern University, Shenyang 110819, China.
The stick-slip phenomenon as a prevalent friction instability poses significant challenges to industry, including frictional vibration, reduced precision, and noise generation. The interfacial interactions between asperities on the surface of materials are critical in influencing stick-slip behavior. This study focused on modifying the asperities on the surface of zinc-coated steel through temper rolling as a new approach to suppress friction-induced stick-slip vibration and noise.
View Article and Find Full Text PDFAm J Primatol
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Department of Biomedical Sciences, Texas A&M University College of Dentistry, Dallas, Texas, USA.
The Cayo Santiago rhesus macaque colony is a renowned primate population that has experienced significant natural and anthropogenic ecological variation in their 85-year history. Demographic and familial information is also tracked and collated for the majority of monkeys. Thus, the health history of rhesus macaques at Cayo Santiago should reflect the impacts of both environmental and genetic factors.
View Article and Find Full Text PDFMol Biol Evol
January 2025
Department of Ecology and Evolutionary Biology, University of California, Santa Cruz, Santa Cruz, CA 95060, USA.
The rate at which mutations arise is a fundamental parameter of biology. Despite progress in measuring germline mutation rates across diverse taxa, such estimates are missing for much of Earth's biodiversity. Here, we present the first estimate of a germline mutation rate from the phylum Mollusca.
View Article and Find Full Text PDFPLoS One
January 2025
Michael Sayegh Faculty of Pharmacy, Aqaba University of Technology, Aqaba, Jordan.
Breast cancer remains a significant challenge in oncology, highlighting the need for alternative therapeutic strategies that target necroptosis to overcome resistance to conventional therapies. Recent investigations into natural compounds have identified 8,12-dimethoxysanguinarine (SG-A) from Eomecon chionantha as a potential necroptosis inducer. This study presents the first computational exploration of SG-A interactions with key necroptotic proteins-RIPK1, RIPK3, and MLKL-through molecular docking, molecular dynamics (MD), density functional theory (DFT), and molecular electrostatic potential (MEP) analyses.
View Article and Find Full Text PDFEnviron Monit Assess
January 2025
Department of Fisheries Resource Management, Faculty of Fisheries Science, Kerala University of Fisheries and Ocean Studies, Kochi, Kerala, 682506, India.
Wetlands are dynamic ecosystems vital for sustaining ecological health and development at regional and global scales. Geospatial tools have emerged as essential for managing wetland ecosystems. This study assessed the spatiotemporal dynamics of water spread in the Point Calimere Wetland, a coastal Ramsar site located along the Bay of Bengal, India, from 1984 to 2023.
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