This paper explores the implications of the observed Bennu particle ejection events for that asteroid's spin rate and orbit evolution, which could complicate interpretation of the Yarkovsky-O'Keefe-Radzievskii-Paddack (YORP) and Yarkovsky effects on this body's spin rate and orbital evolution. Based on current estimates of particle ejection rates, we find that the overall contribution to Bennu's spin and orbital drift is small or negligible as compared to the Yarkovsky and YORP effects. However, if there is a large unseen component of smaller mass ejections or a strong directionality in the ejection events, it could constitute a significant contribution that could mask the overall YORP effect. This means that the YORP effect may be stronger than currently assumed. The analysis is generalized so that the particle ejection effect can be assessed for other bodies that may be subject to similar mass loss events. Further, our model can be modified to address different potential mechanisms of particle ejection, which are a topic of ongoing study.
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http://dx.doi.org/10.1029/2019JE006284 | DOI Listing |
Pharmaceutics
November 2024
Merck Life Science KGaA, Frankfurter Straße 250, 64293 Darmstadt, Germany.
Melt-based 3D printing technologies are currently extensively evaluated for research purposes as well as for industrial applications. Classical approaches often require intermediates, which can pose a risk to stability and add additional complexity to the process. The Advanced Melt Drop Deposition (AMDD) technology, is a 3D printing process that combines the principles of melt extrusion with pressure-driven ejection, similar to injection molding.
View Article and Find Full Text PDFMol Cell Biochem
December 2024
Henan Key Laboratory of Medical Tissue Regeneration, Xinxiang Medical University, Henan Xinxiang, 453003, People's Republic of China.
To investigate the promoting effect of extracellular vesicles derived from myocardial cells (CM-EVs) on the reprogramming of cardiac fibroblasts (CFs) into cardiomyocyte-like cells (iCMs) and their therapeutic effect on myocardial infarction (MI) in rats. Cell experiments: The differential adhesion method was used to obtain Sprague Dawley (SD) suckling rat CFs and cardiomyocytes (CMs), while the ultracentrifugation method was used to obtain CM-EVs. Transmission electron microscopy and nanoparticle tracking technology were used to analyze and determine the morphology and particle size of CM-EVs.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
December 2024
Department of Chemistry, University of California, Berkeley, CA 94720.
Polycyclic aromatic hydrocarbons (PAHs) play a major role in the chemistry of combustion, pyrolysis, and the interstellar medium. Production (or activation) of radical PAHs and propagation of their resulting reactions require efficient dehydrogenation, but the preferred method of hydrogen loss is not well understood. Unimolecular hydrogen ejection (i.
View Article and Find Full Text PDFJ Occup Environ Hyg
December 2024
Health Hazards Prevention Branch, Pittsburgh Mining Research Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Pittsburgh, Pennsylvania.
The development of low-cost research equipment is crucial for enhancing accessibility in scientific research, particularly in the field of respiratory disease transmission. This study presents a novel, customizable cough simulator designed for ad-hoc studies that require precise control over ejection velocity and aerosol size. Constructed from off-the-shelf parts and 3D-printed components, this programmable, piston-driven simulator offers an affordable solution for researchers.
View Article and Find Full Text PDFPharmaceutics
November 2024
Department of Pharmaceutical Technology and Cosmetology, Faculty of Pharmacy, University of Belgrade, Vojvode Stepe 450, 11221 Belgrade, Serbia.
: Improving the production rates of modern tablet presses places ever greater demands on the performance of excipients. Although co-processing has emerged as a promising solution, there is still a lack of directly compressible excipients for modified-release formulations. The aim of the present study was to address this issue by investigating the potential of novel co-processed excipients for the manufacture of modified-release tablets containing ibuprofen.
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