1,179 research outputs found
Astrophysical neutrinos flavored with Beyond the Standard Model physics
We systematically study the allowed parameter space for the flavor
composition of astrophysical neutrinos measured at Earth, including beyond the
Standard Model theories at production, during propagation, and at detection.
One motivation is to illustrate the discrimination power of the next-generation
neutrino telescopes such as IceCube-Gen2. We identify several examples that
lead to potential deviations from the standard neutrino mixing expectation such
as significant sterile neutrino production at the source, effective operators
modifying the neutrino propagation at high energies, dark matter interactions
in neutrino propagation, or non-standard interactions in Earth matter.
IceCube-Gen2 can exclude about 90% of the allowed parameter space in these
cases, and hence will allow to efficiently test and discriminate models. More
detailed information can be obtained from additional observables such as the
energy-dependence of the effect, fraction of electron antineutrinos at the
Glashow resonance, or number of tau neutrino events.Comment: 21 pages, 9 figures, 3 tables, v2: references added, typos corrected,
conclusion unchanged, matches final version in PR
Electrocardiogram in an MRI Environment: Clinical Needs, Practical Considerations, Safety Implications, Technical Solutions and Future Directions
Characterization of an automated spinning-band column as a module for laboratory distillation
Modularization is a promising technology to respond to short product life cycles. Not only in production but also in the laboratory, the concept of modularization can help to quickly explore new products or processes. A modular continuously operated spinning-band distillation column for small product amounts is presented and characterized regarding operating window and separation efficiency. The column can be used either for first product amounts within a small-scale production or as feasibility studies for distillation in a scale-up context with small amounts of resources, energy, and time. By introducing the modular automation concept and a certain degree of automation structures, this column can be operated almost fully automatically and integrated quickly to higher automation structures such as a process orchestration layer
CoSimPy: An open-source python library for MRI radiofrequency Coil EM/Circuit Cosimulation
Background and objectives: The Electromagnetic/Circuit cosimulation method represents a valuable and effective strategy to address those problems where a radiative structure has to interact with external supporting circuitries. This is of particular concern for Magnetic Resonance Imaging (MRI), radiofrequency (RF) coils design, where the supporting circuitry optimisation represents, generally, a crucial aspect. This article presents CoSimPy, an open-source Python circuit simulation library for Electromagnetic/Circuit cosimulations and specifically optimised for MRI, RF coils design.Methods: CoSimPy is designed following an Object-orientated programming. In addition to the essential methods aimed to performed the Electromagnetic/Circuit cosimulations, many others are implemented both to simplify the standard workflow and to evaluate the RF coils performance. In this article, the theory which underlies the fundamental methods of CoSimPy is shown together with the basic framework of the library.Results: In the paper, the reliability of CoSimPy is successfully tested against a full-wave electromagnetic simulations involving a reference setup. The library is made available httys://github.com/umbertozanovello/CoSimpy under together with a detailed documentation providing guidelines and examples. CoSimPy is distributed under the Massachusetts Institute of Technology (MIT) license.Conclusions: CoSimPy demonstrated to be an agile tool employable for Electromagnetic/Circuit cosimulations. Its distribution is meant to fulfil the needs of several researchers also avoiding duplication of effort in writing custom implementations. CoSimPy is under constant development and aims to represent a coworking environment where scientists can implement additional methods whose sharing can represent an advantage for the community. Finally, even if CoSimPy is designed with special focus on MRI, it represents an efficient and practical tool potentially employable wherever electronic devices made of radiative and circuitry components are involved. (C) 2022 Published by Elsevier B.V
Perspective on the mechanism of mass transport-induced (tip-growing) Li dendrite formation by comparing conventional liquid organic solvent with solid polymer-based electrolytes
A major challenge of Li metal electrodes is the growth of high surface area lithium during Li deposition with a variety of possible shapes and growing mechanisms. They are reactive and lead to active lithium losses, electrolyte depletion and safety concerns due to a potential risk of short-circuits and thermal runaway. This work focuses on the mechanism of tip-growing Li dendrite as a particular high surface area lithium morphology. Its formation mechanism is well-known and is triggered during concentration polarization, i.e. during mass (Li+) transport limitations, which has been thoroughly investigated in literature with liquid electrolytes. This work aims to give a stimulating perspective on this formation mechanism by considering solid polymer electrolytes. The in-here shown absence of the characteristic “voltage noise” immediately after complete concentration polarization, being an indicator for tip-growing dendritic growth, rules out the occurrence of the particular tip-growing morphology for solid polymer electrolytes under the specific electrochemical conditions. The generally poorer kinetics of solid polymer electrolytes compared to liquid electrolytes imply lower limiting currents, i.e. lower currents to realize complete concentration polarization. Hence, this longer-lasting Li-deposition times in solid polymer electrolytes are assumed to prevent tip-growing mechanism via timely enabling solid electrolyte interphase formation on fresh Li deposits, while, as stated in previous literature, in liquid electrolytes, Li dendrite tip-growth process is faster than solid electrolyte interphase formation kinetics. It can be reasonably concluded that tip-growing Li dendrites are in general practically unlikely for both, (i) the lower conducting electrolytes like solid polymer electrolytes due to enabling solid electrolyte interphase formation and (ii) good-conducting electrolytes like liquids due to an impractically high current required for concentration polarization
Physical analysis of temperature-dependent effects of amplitude-modulated electromagnetic hyperthermia
Purpose: Preclinical studies and clinical observations suggest that amplitude modulation (AM) below 100 kHz may enhance the intratumoral power absorption of radiofrequency hyperthermia at 13.56 MHz; however, it remains unclear whether AM induces temperature-dependent effects.Methods: We established tumor models assuming typical tumor architectures or cell suspensions to analyze the effects of additional power dissipation. The preconditions for demodulation at cell membranes in situ were outlined. The bioheat transfer equation was solved analytically for the selected models and the possibility of circumscribed temperature increases (point heating) with dependency on the specific absorption rate (SAR) peaks was estimated for centimeter down to nanometer scales.Results: Very-low-frequency (VLF) AM radiofrequency can increase the SAR in the extracellular space or necrosis of tumors as compared to radiofrequencies alone. Such modulation-derived SAR peaks can induce higher temperatures (hot spots) in tumors with necrotic areas of millimeter to centimeter size. However, for lesions 1000, 10,000 and 1014 W/kg for diameters of ∼5 mm, ∼1 mm and ∼10 nm (nanoheating), respectively, would be required to explain the cell kill observed in pre-clinical and clinical data, even with VLF modulation.Conclusion: Our analysis suggests that VLF AM of radiofrequency hyperthermia for a theoretical tumor model cannot induce relevant temperature-dependent effects, as the associated temperature increases caused by the resultant SAR peaks are too small. Further investigation of possible non-temperature-dependent effects is recommended
Open-source magnetic resonance imaging : Improving access, science, and education through global collaboration
The authors would like to thank all the authors that are sharing their work open-source and all the supporters of the Open Source Imaging Initiative (OSI2). The project (21NRM05 and 22HLT02 A4IM) has received funding from the European Partnership on Metrology, co-financed by the European Union's Horizon Europe Research and Innovation Programme and by the Participating States. This research is funded by dtec.bw- Digitalization and Technology Research Center of the Bundeswehr. dtec.bw is funded by the European Union - NextGeneration EU. Part of the image reconstruction used here was developed by the CCP PETMR and CCP SynerBi (https://www.ccppetmr.ac.uk/), UK EPSRC grants EP/P022200/1, EP/M022587/1 and EP/T026693/1. This work made use of computational support by CoSeC, the Computational Science Centre for Research Communities via CCP-SyneRBI and CCPi. RG Nunes acknowledges funding from Fundação para a Ciência e a Tecnologia (grants UIDP/50009/2020 and LA/P/0083/2020). Ruben Pellicer-Guridi has been funded by the European Union's Marie Skłodowska-Curie project nr. 101030868. Open Access funding enabled and organized by Projekt DEAL.Peer reviewe
Deletion of the Ca2+-activated potassium (BK) alpha-subunit but not the BK-beta-1-subunit leads to progressive hearing loss
The large conductance voltage- and Ca2+-activated potassium (BK) channel has been suggested to play an important role in the signal transduction process of cochlear inner hair cells. BK channels have been shown to be composed of the pore-forming alpha-subunit coexpressed with the auxiliary beta-1-subunit. Analyzing the hearing function and cochlear phenotype of BK channel alpha-(BKalpha–/–) and beta-1-subunit (BKbeta-1–/–) knockout mice, we demonstrate normal hearing function and cochlear structure of BKbeta-1–/– mice. During the first 4 postnatal weeks also, BKalpha–/– mice most surprisingly did not show any obvious hearing deficits. High-frequency hearing loss developed in BKalpha–/– mice only from ca. 8 weeks postnatally onward and was accompanied by a lack of distortion product otoacoustic emissions, suggesting outer hair cell (OHC) dysfunction. Hearing loss was linked to a loss of the KCNQ4 potassium channel in membranes of OHCs in the basal and midbasal cochlear turn, preceding hair cell degeneration and leading to a similar phenotype as elicited by pharmacologic blockade of KCNQ4 channels. Although the actual link between BK gene deletion, loss of KCNQ4 in OHCs, and OHC degeneration requires further investigation, data already suggest human BK-coding slo1 gene mutation as a susceptibility factor for progressive deafness, similar to KCNQ4 potassium channel mutations. © 2004, The National Academy of Sciences. Freely available online through the PNAS open access option
- …