The scalar and electromagnetic fields of charges uniformly accelerated in de Sitter spacetime are constructed. They represent the generalization of the Born solutions describing fields of two particles with hyperbolic motion in flat spacetime. In the limit Lambda-->0, the Born solutions are retrieved. Since in the de Sitter universe the infinities I+/- are spacelike, the radiative properties of the fields depend on the way in which a given point of I+/- is approached. The fields must involve both retarded and advanced effects: Purely retarded fields do not satisfy the constraints at the past infinity I-.
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http://dx.doi.org/10.1103/PhysRevLett.88.211101 | DOI Listing |
Clin Epigenetics
December 2024
School of Mathematical and Statistical Sciences, University of Galway, Galway, Ireland.
Background: Epigenetic age (EA) is an age estimate, developed using DNA methylation (DNAm) states of selected CpG sites across the genome. Although EA and chronological age are highly correlated, EA may not increase uniformly with time. Departures, known as epigenetic age acceleration (EAA), are common and have been linked to various traits and future disease risk.
View Article and Find Full Text PDFACS Omega
December 2024
Department of Physical Chemistry, P. J. Šafárik University in Košice, Moyzesova 11, 041 01 Košice, Slovakia.
In the past decades, iron has been one of the intensively studied biodegradable metals due to its suitable mechanical properties, but it suffers from slow degradation in a physiological environment and low bioactivity. In this work, the beneficial properties of ceramic and polymer coatings were merged to enhance the corrosion properties and biological compatibility of Fe-based biomaterials. A new bilayer coating for Fe-based biomaterials that speeds up degradation while offering controlled, localized drug release to prevent infections was prepared.
View Article and Find Full Text PDFAdv Mater
December 2024
State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Materials Science and Engineering, Institute of Functional Materials, Donghua University, Shanghai, 201620, China.
The electrochemical nitrate reduction reaction (NO RR) for ammonia (NH) synthesis represents a significant technological advancement, yet it involves a cascade of elementary reactions alongside various intermediates. Thus, the development of multi-site catalysts for enhancing NO RR and understanding the associated reaction mechanisms for NH synthesis is vital. Herein, a versatile approach is presented to construct platinum based high-entropy intermetallic (HEI) library for NH synthesis.
View Article and Find Full Text PDFJ Environ Manage
December 2024
Korea Biochar Research Center, Division of Environmental Science and Ecological Engineering, Korea University, Seoul, 02841, Korea.
Pristine or modified nanoscale zero-valent iron (nZVI) synthesized though conventional chemical reduction have been widely recommended for remediating metal(loid)-contaminated water. However, their eco-friendliness is often challenged with the concomitant bio-toxicity and secondary environmental risks. Alternatively, this study utilized waste tea leaves extract and remaining residue as the reducing agent and pyrolytic matrix to innovatively fabricate a green synthesized nZVI impregnated tea residue biochar (G-nZVI/TB).
View Article and Find Full Text PDFSmall
December 2024
Hydrogen Research Department, Korea Institute of Energy Research (KIER), 152 Gajeong-ro, Yuseong-gu, Daejeon, 34129, Republic of Korea.
Herein, a B-site-rich Ru/MgAlO nanocatalyst for the production of CO-free hydrogen from ammonia (NH) is synthesized using the polyol method. The polyol method enables size-sensitive Ru-nanoparticle growth and controlled B-site formation on the catalyst by tuning the carbon-chain length of the polyol solvent used, obviating the use of a separate stabilizer and enhancing electron donation from Ru (with a high surface electron density) and π-back bonding. The Ru/MgAlO (BG) catalyst synthesized using butylene glycol (a long-carbon-chain solvent) contains 2.
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