Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 708
Filtrar
1.
J Cell Mol Med ; 28(19): e70132, 2024 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-39350724

RESUMO

Aging is a risk factor for various human disorders, including cancer. Current literature advocates that the primary principles of aging depend on the endogenous stress-induced DNA damage caused by reactive oxygen species 50 Hz low-frequency magnetic field was suggested to induce DNA damage and chromosomal instability. NF-kB, activated by DNA damage, is upregulated in age-related cancers and inhibition of NF-kB results in aging-related delayed pathologies. Metformin (Met), an NF-kB inhibitor, significantly reduces both NF-kB activation and expression in aging and cancer. This in vitro study, therefore, was set out to assess the effects of 5mT MF in 50 Hz frequency and Met treatment on the viability and proliferation of aged mouse NIH/3T3 fibroblasts and expression of RELA/p65, matrix metalloproteinases MMP2 and MMP9, and E-cadherin (CDH1) genes. The trypan blue exclusion assay was used to determine cell viability and the BrdU incorporation assay to determine cell proliferation. The MMP-2/9 protein analysis was carried out by immunocytochemistry, NF-kB activity by ELISA and the expressions of targeted genes by qRT-PCR methods. Four doses of Met (500 uM, 1 mM, 2 mM and 10 mM) suppressed both the proliferation and viability of fibroblasts exposed to the MF in a dose-dependent pattern, and the peak inhibition was recorded at the 10 mM dose. Met reduced the expression of NF-kB, and MMP2/9, elevated CDH1 expression and suppressed NF-kB activity. These findings suggest that Met treatment suppresses the carcinogenic potential of 50 Hz MFs in aged mouse fibroblasts, possibly through modulation of NF-kB activation and epithelial-mesenchymal transition modulation.


Assuntos
Proliferação de Células , Sobrevivência Celular , Fibroblastos , Campos Magnéticos , Metformina , NF-kappa B , Animais , Metformina/farmacologia , Camundongos , Fibroblastos/metabolismo , Fibroblastos/efeitos dos fármacos , Células NIH 3T3 , NF-kappa B/metabolismo , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Carcinogênese/efeitos dos fármacos , Carcinogênese/genética , Carcinogênese/patologia , Fator de Transcrição RelA/metabolismo , Metaloproteinase 9 da Matriz/metabolismo , Metaloproteinase 9 da Matriz/genética , Metaloproteinase 2 da Matriz/metabolismo , Metaloproteinase 2 da Matriz/genética , Caderinas/metabolismo , Caderinas/genética , Senescência Celular/efeitos dos fármacos
2.
Open Res Eur ; 4: 112, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-39386150

RESUMO

As we learn more about the multi-scale interstellar medium (ISM) of our Galaxy, we develop a greater understanding for the complex relationships between the large-scale diffuse gas and dust in Giant Molecular Clouds (GMCs), how it moves, how it is affected by the nearby massive stars, and which portions of those GMCs eventually collapse into star forming regions. The complex interactions of those gas, dust and stellar populations form what has come to be known as the ecology of our Galaxy. Because we are deeply embedded in the plane of our Galaxy, it takes up a significant fraction of the sky, with complex dust lanes scattered throughout the optically recognizable bands of the Milky Way. These bands become bright at (sub-)millimetre wavelengths, where we can study dust thermal emission and the chemical and kinematic signatures of the gas. To properly study such large-scale environments, requires deep, large area surveys that are not possible with current facilities. Moreover, where stars form, so too do planetary systems, growing from the dust and gas in circumstellar discs, to planets and planetesimal belts. Understanding the evolution of these belts requires deep imaging capable of studying belts around young stellar objects to Kuiper belt analogues around the nearest stars. Here we present a plan for observing the Galactic Plane and circumstellar environments to quantify the physical structure, the magnetic fields, the dynamics, chemistry, star formation, and planetary system evolution of the galaxy in which we live with AtLAST; a concept for a new, 50m single-dish sub-mm telescope with a large field of view which is the only type of facility that will allow us to observe our Galaxy deeply and widely enough to make a leap forward in our understanding of our local ecology.


There are many individual components contributing to the overall evolution of our Galaxy, the Milky Way. Through understanding the physics and chemistry of the Galaxy around us, we better understand our origins, our environment, and where we're going. Here we outline a number of observational surveys of our Galaxy that would produce a step change in our understanding of the evolution of the Galaxy around us, both as a template for others, and as the only way of understanding our place in the larger Universe. We present surveys of the Galactic Plane focusing on the dust and magnetic fields, chemistry, and dynamics of the gas. We then suggest surveys of local stars and star forming regions to uncover the origins of stars, planets and how those planetary systems evolve over the course of their lives, helping to put our Sun and Solar System in context. These types of observations require simultaneously sensitive, long wavelength (between 0.3 and 3 millimetre) observations as well as a large coverage of the sky, and cannot be done with current observatories operating at these wavelengths. Future leaps in understanding these systems will require a new telescope; a large telescope at a good observing location with a large field of view. This telescope, the Atacama Large Sub-mm Telescope (AtLAST; http://atlast-telescope.org/) is being developed, and here we are presenting the science cases for this new telescope from the point of view of our Galaxy. Together, these studies will revolutionise our understanding of the history and evolution of our Galaxy and bring us yet another step closer to understanding our place in, and the evolution of, our Universe.

3.
Angew Chem Int Ed Engl ; : e202412521, 2024 Oct 07.
Artigo em Inglês | MEDLINE | ID: mdl-39374103

RESUMO

Here we report on the Magneto-Chiral Dichroism (MChD) detected through visible and near-infrared light absorption of two enantiomeric pairs of ErIII and TmIII chiral complexes featuring a propeller-like molecular structure. The magnetic properties show typical features of isolated paramagnetic ions associated with 4I15/2 and 3H6 ground state terms. MChD spectroscopy shows high gMChD dissymmetry factors of ca. 0.12 T-1 and 0.05 T-1 (T = 4.0 K and B = 1.0 T) for ErIII and TmIII, respectively, associated with their magnetic-dipole allowed 4I13/2 ← 4I15/2 and 3H5 ← 3H6 transitions. MChD signals of the two complexes were detected up to room temperature and under magnetic fields up to 5.0 T. For the first time, the MChD results reported here are discussed in the context of the Richardson theory of lanthanide optical activity and provide clear indications on the strongest MChD-active electronic transitions of lanthanide complexes.

4.
Proc Natl Acad Sci U S A ; 121(37): e2403067121, 2024 Sep 10.
Artigo em Inglês | MEDLINE | ID: mdl-39240969

RESUMO

The unconventional superconductor UTe[Formula: see text] exhibits numerous signatures of spin-triplet superconductivity-a rare state of matter which could enable quantum computation protected against decoherence. UTe[Formula: see text] possesses a complex phase landscape comprising two magnetic field-induced superconducting phases, a metamagnetic transition to a field-polarized state, along with pair- and charge-density wave orders. However, contradictory reports between studies performed on UTe[Formula: see text] specimens of varying quality have severely impeded theoretical efforts to understand the microscopic origins of the exotic superconductivity. Here, we report a comprehensive suite of high magnetic field measurements on a generation of pristine quality UTe[Formula: see text] crystals. Our experiments reveal a significantly revised high magnetic field superconducting phase diagram in the ultraclean limit, showing a pronounced sensitivity of field-induced superconductivity to the presence of crystalline disorder. We employ a Ginzburg-Landau model that excellently captures this acute dependence on sample quality. Our results suggest that in close proximity to a field-induced metamagnetic transition the enhanced role of magnetic fluctuations-that are strongly suppressed by disorder-is likely responsible for tuning UTe[Formula: see text] between two distinct spin-triplet superconducting phases.

5.
J Infect ; 89(5): 106271, 2024 Sep 13.
Artigo em Inglês | MEDLINE | ID: mdl-39278276

RESUMO

OBJECTIVES: We aimed to evaluate the effectiveness of alternating magnetic fields (AMF) combined with antibiotics in reducing Staphylococcus aureus biofilm on metal implants in a large animal model, compared to antibiotics alone. METHODS: Metal plates were inoculated with a clinical MRSA strain and then implanted into thirty-three ewes divided into three groups: positive control, linezolid only, and a combination of linezolid and AMF. Animals had either titanium or cobalt-chrome plates and were sacrificed at 5 or 21 days post-implantation. Blood and tissue samples were collected at various time points post-AMF treatment. RESULTS: In vivo efficacy studies demonstrated significant biofilm reduction on titanium and cobalt-chrome implants with AMF-linezolid combination treatment compared to controls. Significant bacterial reductions were also observed in surrounding tissues and bones. Cytokine analysis showed improved inflammatory responses with combination therapy, and histopathology confirmed reduced inflammation, necrosis, and bacterial presence, especially at 5 days post-implantation. CONCLUSIONS: This study demonstrates that combining AMF with antibiotics significantly reduces biofilm-associated infections on metal implants in a large animal model. Numerical simulations confirmed targeted heating, and in vivo results showed substantial bacterial load reduction and reduced inflammatory response. These findings support the potential of AMF as a non-invasive treatment for prosthetic joint infections.

6.
Micron ; 187: 103719, 2024 Sep 16.
Artigo em Inglês | MEDLINE | ID: mdl-39293141

RESUMO

Scanning Tunneling Microscopy (STM) is widely used for observing atomic structures due to its ultra-high spatial resolution. As the core units of STM, the coarse stepper motor and imaging unit, have conflicting size requirements for piezo tubes. Longer piezo tubes yield greater output force and easier movement for the motor, while shorter tubes enhance imaging precision and stability for the scanner. Traditional STMs typically employ a large piezo tube for coarse stepping and a smaller one for independent imaging to address this issue. Here, we present the new design of a piezo tube stacked STM, in which two independent piezo tubes act together during tip-sample approach process and only one shorter tube works during scanning imaging. Both tubes are fixed to the framework, ensuring high rigidity and compactness. The new design enables us to achieve both coarse stepping and imaging functions with a total length of only 25 mm for the two tubes, effectively reducing the length of whole STM, facilitating its integration into narrow low-temperature spaces for imaging applications. Using this device, we obtained high-quality atomic images of graphite sample surfaces at room temperature. Continuous scanning imaging of the same area on Au film at 300 K demonstrates the STM's high stability in both X-Y and Z directions. Atomic images, I-V spectra, and di/dv spectra obtained at 2 K on graphite surface illustrate the excellent application potential of this device in low-temperature environments. Finally, atomic images obtained of graphite in sweeping the magnetic fields from 0 T to 11 T in a huge vibrational dry magnet prove the new STM's excellent performance in extreme conditions.

7.
Sci Rep ; 14(1): 18444, 2024 08 08.
Artigo em Inglês | MEDLINE | ID: mdl-39117725

RESUMO

Glioblastoma (GBM) is associated with a median survival rate of less than 15 months, necessitating innovative treatment approaches. This study investigates the safety and efficacy of the low-frequency magnetic field (LFMF) OM-100 instrument in GBM therapy. In vitro experiments utilized normal astrocyte and GBM cell lines, determining that OM-100 at 100 kHz for 72 h selectively targeted GBM cells without harming normal cells. Subsequent analyses revealed OM-100's impact on cell viability, apoptosis, migration, invasion, reactive oxide species levels, and PD-L1 expression. In vivo studies on mice with U87-induced GBM demonstrated OM-100's synergy with anti-PD-1 therapy, leading to significant tumor volume reduction and increased apoptosis. Notably, OM-100 exhibited safety in healthy mice. Overall, OM-100 could enhance anti-PD-1 immunotherapy effectiveness probably by directly inhibiting tumor proliferation and migration as well as promoting PD-L1 expression, offering a promising therapeutic strategy for GBM treatment.


Assuntos
Proliferação de Células , Glioblastoma , Imunoterapia , Receptor de Morte Celular Programada 1 , Glioblastoma/terapia , Glioblastoma/tratamento farmacológico , Glioblastoma/patologia , Glioblastoma/metabolismo , Animais , Camundongos , Humanos , Linhagem Celular Tumoral , Receptor de Morte Celular Programada 1/antagonistas & inibidores , Receptor de Morte Celular Programada 1/metabolismo , Imunoterapia/métodos , Proliferação de Células/efeitos dos fármacos , Antígeno B7-H1/metabolismo , Antígeno B7-H1/antagonistas & inibidores , Neoplasias Encefálicas/tratamento farmacológico , Neoplasias Encefálicas/imunologia , Neoplasias Encefálicas/terapia , Apoptose/efeitos dos fármacos , Movimento Celular/efeitos dos fármacos , Inibidores de Checkpoint Imunológico/farmacologia , Inibidores de Checkpoint Imunológico/uso terapêutico , Ensaios Antitumorais Modelo de Xenoenxerto , Magnetoterapia/métodos , Sobrevivência Celular/efeitos dos fármacos
8.
Open Res Eur ; 4: 140, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-39139813

RESUMO

Observations at (sub-)millimeter wavelengths offer a complementary perspective on our Sun and other stars, offering significant insights into both the thermal and magnetic composition of their chromospheres. Despite the fundamental progress in (sub-)millimeter observations of the Sun, some important aspects require diagnostic capabilities that are not offered by existing observatories. In particular, simultaneously observations of the radiation continuum across an extended frequency range would facilitate the mapping of different layers and thus ultimately the 3D structure of the solar atmosphere. Mapping large regions on the Sun or even the whole solar disk at a very high temporal cadence would be crucial for systematically detecting and following the temporal evolution of flares, while synoptic observations, i.e., daily maps, over periods of years would provide an unprecedented view of the solar activity cycle in this wavelength regime. As our Sun is a fundamental reference for studying the atmospheres of active main sequence stars, observing the Sun and other stars with the same instrument would unlock the enormous diagnostic potential for understanding stellar activity and its impact on exoplanets. The Atacama Large Aperture Submillimeter Telescope (AtLAST), a single-dish telescope with 50m aperture proposed to be built in the Atacama desert in Chile, would be able to provide these observational capabilities. Equipped with a large number of detector elements for probing the radiation continuum across a wide frequency range, AtLAST would address a wide range of scientific topics including the thermal structure and heating of the solar chromosphere, flares and prominences, and the solar activity cycle. In this white paper, the key science cases and their technical requirements for AtLAST are discussed.


Observations of our Sun and other stars at wavelengths of around one millimeter, i.e. in the range between infrared and radio waves, present a valuable complementary perspective. Despite significant technological advancements, certain critical aspects necessitate diagnostic capabilities not offered by current observatories. The proposed Atacama Large Aperture Submillimeter Telescope (AtLAST), featuring a 50-meter aperture and slated for construction at a high altitude in Chile's Atacama desert, promises to address these observational needs. Equipped with novel detectors that would cover a wide frequency range, AtLAST could unlock a plethora of scientific studies contributing to a better understanding of our host star. Simultaneous observations over a broad frequency range at rapid succession would enable the imaging of different layers of the Sun, thus elucidating the three-dimensional thermal and magnetic structure of the solar atmosphere and providing important clues for many long-standing central questions such as how the outermost layers of the Sun are heated to very high temperatures, the nature of large-scale structures like prominences, and how flares and coronal mass ejections, i.e. enormous eruptions, are produced. The latter is of particular interest to modern society due to the potentially devastating impact on the technological infrastructure we depend on today. Another unique possibility would be to study the Sun's long-term evolution in this wavelength range, which would yield important insights into its activity cycle. Moreover, the Sun serves as a fundamental reference for other stars as, due to its proximity, it is the only star that can be investigated in such detail. The results for the Sun would therefore have direct implications for understanding other stars and their impact on exoplanets. This article outlines the key scientific objectives and technical requirements for solar observations with AtLAST.

9.
Int J Mol Sci ; 25(16)2024 Aug 17.
Artigo em Inglês | MEDLINE | ID: mdl-39201657

RESUMO

Recently, magnetic fields (MFs) have received major attention due to their potential therapeutic applications and biological effects. This review provides a comprehensive analysis of the cellular and molecular impacts of MFs, with a focus on both in vitro and in vivo studies. We investigate the mechanisms by which MFs influence cell behavior, including modifications in gene expression, protein synthesis, and cellular signaling pathways. The interaction of MFs with cellular components such as ion channels, membranes, and the cytoskeleton is analyzed, along with their effects on cellular processes like proliferation, differentiation, and apoptosis. Molecular insights are offered into how MFs modulate oxidative stress and inflammatory responses, which are pivotal in various pathological conditions. Furthermore, we explore the therapeutic potential of MFs in regenerative medicine, cancer treatment, and neurodegenerative diseases. By synthesizing current findings, this article aims to elucidate the complex bioeffects of MFs, thereby facilitating their optimized application in medical and biotechnological fields.


Assuntos
Campos Magnéticos , Humanos , Animais , Estresse Oxidativo , Transdução de Sinais , Apoptose , Diferenciação Celular , Proliferação de Células , Citoesqueleto/metabolismo
10.
Cells ; 13(15)2024 Jul 29.
Artigo em Inglês | MEDLINE | ID: mdl-39120305

RESUMO

Transient receptor potential (TRP) channels are broadly implicated in the developmental programs of most tissues. Amongst these tissues, skeletal muscle and adipose are noteworthy for being essential in establishing systemic metabolic balance. TRP channels respond to environmental stimuli by supplying intracellular calcium that instigates enzymatic cascades of developmental consequence and often impinge on mitochondrial function and biogenesis. Critically, aminoglycoside antibiotics (AGAs) have been shown to block the capacity of TRP channels to conduct calcium entry into the cell in response to a wide range of developmental stimuli of a biophysical nature, including mechanical, electromagnetic, thermal, and chemical. Paradoxically, in vitro paradigms commonly used to understand organismal muscle and adipose development may have been led astray by the conventional use of streptomycin, an AGA, to help prevent bacterial contamination. Accordingly, streptomycin has been shown to disrupt both in vitro and in vivo myogenesis, as well as the phenotypic switch of white adipose into beige thermogenic status. In vivo, streptomycin has been shown to disrupt TRP-mediated calcium-dependent exercise adaptations of importance to systemic metabolism. Alternatively, streptomycin has also been used to curb detrimental levels of calcium leakage into dystrophic skeletal muscle through aberrantly gated TRPC1 channels that have been shown to be involved in the etiology of X-linked muscular dystrophies. TRP channels susceptible to AGA antagonism are critically involved in modulating the development of muscle and adipose tissues that, if administered to behaving animals, may translate to systemwide metabolic disruption. Regenerative medicine and clinical communities need to be made aware of this caveat of AGA usage and seek viable alternatives, to prevent contamination or infection in in vitro and in vivo paradigms, respectively.


Assuntos
Aminoglicosídeos , Antibacterianos , Canais de Potencial de Receptor Transitório , Humanos , Animais , Antibacterianos/farmacologia , Canais de Potencial de Receptor Transitório/metabolismo , Aminoglicosídeos/farmacologia , Músculo Esquelético/metabolismo , Músculo Esquelético/efeitos dos fármacos , Tecido Adiposo/metabolismo , Tecido Adiposo/efeitos dos fármacos
11.
Biomolecules ; 14(8)2024 Jul 31.
Artigo em Inglês | MEDLINE | ID: mdl-39199317

RESUMO

Melatonin is a relic, due to its millions-of-years-old presence in chemical reactions, found in evolutionarily diverse organisms. It has a multidirectional biological function. It controls diurnal rhythms, redox homeostasis, intestinal motor functions, mitochondrial biogenesis and fetal development and has antioxidant effects. It also has analgesic and therapeutic effects. The purpose of this paper is to describe the role of melatonin in vital processes occurring in interaction with the environment, with particular reference to various magnetic fields ubiquitous in the life of animate matter, especially radio frequency/extra low frequency (RF/ELF EMF) and static magnetic fields. The most important part of this article is to describe the potential effects of magnetic fields on melatonin secretion and the resulting possible health effects. Melatonin in some cases positively amplifies the electromagnetic signal, intensifying health effects, such as neurogenesis, analgesic effects or lowering blood pressure. In other cases, it is a stimulus that inhibits the processes of destruction and aggravation of lesions. Sometimes, however, in contrast to the beneficial effects of electromagnetic fields in therapy, they intensify pathogenic effects, as in multiple sclerosis by intensifying the inflammatory process.


Assuntos
Campos Magnéticos , Melatonina , Melatonina/metabolismo , Melatonina/farmacologia , Humanos , Animais , Antioxidantes/farmacologia , Antioxidantes/metabolismo , Campos Eletromagnéticos , Ritmo Circadiano/efeitos dos fármacos
12.
J Magn Reson ; 366: 107744, 2024 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-39096714

RESUMO

We present field-domain rapid-scan (RS) electron paramagnetic resonance (EPR) at 8.6T and 240GHz. To enable this technique, we upgraded a home-built EPR spectrometer with an FPGA-enabled digitizer and real-time processing software. The software leverages the Hilbert transform to recover the in-phase (I) and quadrature (Q) channels, and therefore the raw absorptive and dispersive signals, χ' and χ'', from their combined magnitude (I2+Q2). Averaging a magnitude is simpler than real-time coherent averaging and has the added benefit of permitting long-timescale signal averaging (up to at least 2.5×106 scans) because it eliminates the effects of source-receiver phase drift. Our rapid-scan (RS) EPR provides a signal-to-noise ratio that is approximately twice that of continuous wave (CW) EPR under the same experimental conditions, after scaling by the square root of acquisition time. We apply our RS EPR as an extension of the recently reported time-resolved Gd-Gd EPR (TiGGER) [Maity et al., 2023], which is able to monitor inter-residue distance changes during the photocycle of a photoresponsive protein through changes in the Gd-Gd dipolar couplings. RS, opposed to CW, returns field-swept spectra as a function of time with 10ms time resolution, and thus, adds a second dimension to the static field transients recorded by TiGGER. We were able to use RS TiGGER to track time-dependent and temperature-dependent kinetics of AsLOV2, a light-activated phototropin domain found in oats. The results presented here combine the benefits of RS EPR with the improved spectral resolution and sensitivity of Gd chelates at high magnetic fields. In the future, field-domain RS EPR at high magnetic fields may enable studies of other real-time kinetic processes with time resolutions that are otherwise difficult to access in the solution state.


Assuntos
Proteínas , Temperatura , Espectroscopia de Ressonância de Spin Eletrônica/métodos , Proteínas/química , Algoritmos , Software , Razão Sinal-Ruído
13.
Artigo em Inglês | MEDLINE | ID: mdl-38966754

RESUMO

Galaxies are observed to host magnetic fields with a typical total strength of around 15  µ G. A coherent large-scale field constitutes up to a few microgauss of the total, while the rest is built from strong magnetic fluctuations over a wide range of spatial scales. This represents sufficient magnetic energy for it to be dynamically significant. Several questions immediately arise: What is the physical mechanism that gives rise to such magnetic fields? How do these magnetic fields affect the formation and evolution of galaxies? In which physical processes do magnetic fields play a role, and how can that role be characterized? Numerical modelling of magnetized flows in galaxies is playing an ever-increasing role in finding those answers. We review major techniques used for these models. Current results strongly support the conclusion that field growth occurs during the formation of the first galaxies on timescales shorter than their accretion timescales due to small-scale turbulent dynamos. The saturated small-scale dynamo maintains field strengths at only a few percent of equipartition with turbulence. This is in contradiction with the observed magnitude of turbulent fields, but may be reconciled by the further contribution to the turbulent field of the large-scale dynamo. The subsequent action of large-scale dynamos in differentially rotating discs produces field strengths observed in low redshift galaxies, where it reaches equipartition with the turbulence and has substantial power at large scales. The field structure resulting appears consistent with observations including Faraday rotation and polarisation from synchrotron and dust thermal emission. Major remaining challenges include scaling numerical models toward realistic scale separations and Prandtl and Reynolds numbers.

14.
ChemSusChem ; : e202400675, 2024 Jul 25.
Artigo em Inglês | MEDLINE | ID: mdl-39052466

RESUMO

The application of sodium metal battery is hampered by the large volume change and uncontrollable top growth of Na metal. Herein, a dual strategy including constructing a three-dimensional gradient ZnO/Fe0.7Co0.3 (ZFC) framework of decreasing sodiophilic capability from bottom to top, and imposing magnetic fields based on magnetohydrodynamic (MHD) effect, is proposed to regulate the sodium deposition/stripping behavior and realize the bottom-up deposition of Na. Therefore, the ZFC framework under a magnetic field of 200 mT exhibits high electrochemical reversibility with a Coulombic efficiency of 99.77 % at 1 mA cm-2 and 1 mAh cm-2. Meanwhile, the ZFC composite anode (ZFC@Na) with the magnetic field of 200 mT delivers a small polarization voltage of approximately10 mV and long cycle life of more than 2500 h at 5 mA cm-2 and 5 mAh cm-2 in symmetric cells, along with good cycle stability in ZFC@Na||Na3V2(PO4)3 full cells (200 cycles at 1 C with a high capacity retention of 98 %). Accordingly, the novel strategy of combining magnetic fields and sodiophilic gradient frameworks provides a perspective to solve the issues of sodium dendrite growth.

15.
J Phys Condens Matter ; 36(44)2024 Aug 06.
Artigo em Inglês | MEDLINE | ID: mdl-39059430

RESUMO

The honeycomb Kitaev model describes aZ2spin liquid with topological order and fractionalized excitations consisting of gappedπ-fluxes and free Majorana fermions. Competing interactions, even when not very strong, are known to destabilize the Kitaev spin liquid. Magnetic fields are a convenient parameter for tuning between different phases of the Kitaev systems, and have even been investigated for potentially counteracting the effects of other destabilizing interactions leading to a revival of the topological phase. Here we review the progress in understanding the effects of magnetic fields on some of the perturbed Kitaev systems, particularly on fractionalization and topological order.

16.
Phys Med Biol ; 2024 Jul 25.
Artigo em Inglês | MEDLINE | ID: mdl-39053512

RESUMO

OBJECTIVE: To investigate magnetic field effects on the dose distribution and ionization chambers response in carbon ion reference fields and determine magnetic field correction factors for chambers of different volumes. Approach: The response of six Farmer-type chambers with varying radii (1 to 6 mm, termed as R1 to R6) was measured in magnetic fields up to 1 T in 0.1 T increments using an experimental electromagnet and compared with Monte Carlo simulations. Chamber readings were measured in the entrance region of a monoenergetic carbon ion beam of 390.75 MeV/u. A lower energy of 200.28 MeV/u was applied to chamber R3 for comparison. Polarity and recombination corrections were investigated for the R3 chamber. The local dose change induced by the magnetic field was calculated by Monte Carlo, which together with change of the chamber's response, was used to calculate the final magnetic field correction factors. Main results: The dependence of the chamber response on the magnetic field was non-linear and volume-dependent. Maximum changes ranged from 0.30% (R4) to 0.62% (R5) at 0.2 T. For R3, the response for the lower energy was systematically decreased by 0.2% in the range of 0.2 T to 0.7 T. No significant effect of the magnetic field on polarity and ion recombination correction was found. The maximum variation of the local dose was found to be (0.03±0.08)% at 0.2 T for beam energy of 390.75 MeV/u. Magnetic field correction factors for the different chambers ranged from 0.28% (R4) to 0.60% (R5). Significance: This study provides the first detailed analysis of chambers' response to magnetic flux densities of up to 1 T using chambers of different radii and comparison with simulations. By combining the chamber response alterations with local dose changes magnetic field correction factors were calculated for all six chambers, including the commercial Farmer-type chamber.

17.
BioTechnologia (Pozn) ; 105(2): 149-158, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38988363

RESUMO

In recent years, with the increased production of oilseed rape, there has been a simultaneous enhancement in reports on pathogens causing diseases. Magnetic technology has been recognized as a new agricultural method aimed at improving health and crop production. In this work, the effect of magnetic fields was studied on the mycelial growth and conidia formation of Leptosphaeria maculans Gol125 and Leptosphaeria biglobosa KH36, the causal agents of Phoma stem cancer (blackleg) disease in rapeseed. In addition, seeds exposed to eight direct frequencies of magnetic fields were impregnated with pathogen suspension and grown under greenhouse conditions. The growth speed of both pathogen isolates decreased by 1-28% in GOL125 and 6-46% in KH36 over time in cultures exposed to magnetic fields. However, the number of conidia increased significantly under magnetic field exposure, reaching 5.4 × 107 and 7.7 × 107 SFU/ml in KH36 and GOL125 isolates, respectively. Furthermore, in greenhouse conditions, an increase in photosynthetic pigment levels was observed in almost all of the magnetic field-treated plants. In addition, disease incidence decreased by around 6% in the magnetic field-treated plants. This study represents the first evaluation of magnetic technology in controlling plant diseases. The use of magnetic fields may present a viable strategy for a sustainable production system; however, it requires further advanced studies to improve plant health and productivity.

18.
Bioact Mater ; 40: 524-540, 2024 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-39040567

RESUMO

Iron and its alloys are attractive as biodegradable materials because of their low toxicity and suitable mechanical properties; however, they generally have a slow degradation rate. Given that corrosion is an electrochemical phenomenon where an exchange of electrons takes place, the application of magnetic fields from outside the body may accelerate the degradation of a ferrous temporary implant. In the present study, we have investigated the effect of alternating and direct low magnetic field (H = 6.5 kA/m) on the corrosion process of pure iron (Fe) and an iron-manganese alloy (FeMnC) in modified Hanks' solution. A 14-day static immersion test was performed on the materials. The corrosion rate was assessed by mass and cross-sectional loss measurements, scanning electron microscopy, X-ray diffractometry, Fourier-transform infrared spectroscopy and X-ray photoelectron spectroscopy before and after degradation. The results show that the presence of magnetic fields significantly accelerates the degradation rate of both materials, with the corrosion rate being twice as high in the case of Fe and almost three times as high for FeMnC. In addition, a homogenous degradation layer is formed over the entire surface and the chemical composition of the degradation products is the same regardless of the presence of a magnetic field.

19.
Int J Mol Sci ; 25(14)2024 Jul 16.
Artigo em Inglês | MEDLINE | ID: mdl-39063025

RESUMO

Pulsed electromagnetic fields (PEMFs) are recognized for their potential in regenerative medicine, offering a non-invasive avenue for tissue rejuvenation. While prior research has mainly focused on their effects on bone and dermo-epidermal tissues, the impact of PEMFs on nervous tissue, particularly in the context of neuropathy associated with the diabetic foot, remains relatively unexplored. Addressing this gap, our preliminary in vitro study investigates the effects of complex magnetic fields (CMFs) on glial-like cells derived from mesenchymal cell differentiation, serving as a model for neuropathy of the diabetic foot. Through assessments of cellular proliferation, hemocompatibility, mutagenicity, and mitochondrial membrane potential, we have established the safety profile of the system. Furthermore, the analysis of microRNAs (miRNAs) suggests that CMFs may exert beneficial effects on cell cycle regulation, as evidenced by the upregulation of the miRNAs within the 121, 127, and 142 families, which are known to be associated with mitochondrial function and cell cycle control. This exploration holds promise for potential applications in mitigating neuropathic complications in diabetic foot conditions.


Assuntos
Neuropatias Diabéticas , Campos Eletromagnéticos , MicroRNAs , Mitocôndrias , Estresse Oxidativo , Mitocôndrias/metabolismo , Neuropatias Diabéticas/terapia , Neuropatias Diabéticas/metabolismo , Humanos , MicroRNAs/genética , MicroRNAs/metabolismo , Doenças Neuroinflamatórias/metabolismo , Doenças Neuroinflamatórias/terapia , Doenças Neuroinflamatórias/etiologia , Potencial da Membrana Mitocondrial , Proliferação de Células , Magnetoterapia/métodos
20.
J Adv Periodontol Implant Dent ; 16(1): 36-43, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-39027204

RESUMO

Background: Non-ionizing electromagnetic field (EMF) exposure therapies are non-invasive and safe treatment options that can potentially change available treatments. In this review, we examined the applications of such therapies in dental implant surgery by conducting a systematic review. Methods: A comprehensive search of several international electronic databases was conducted from inception to December 14, 2022. This review included interventional studies that evaluated the advantages of adjunctive magnetic or combined EMFs on dental implants compared to conventional treatments. Results: From a total of 1695 studies, 12 preclinical and clinical studies were selected, discussing EMF-based treatments for enhancing implant stability, osteogenesis, and osseointegration, as well as alleviating post-implant surgery manifestations. Almost all studies on maxillary and mandibular implant stability showed beneficial effects of non-ionizing EMF in humans. Most studies evaluating osteogenesis and osseointegration indicated that EMF exposure could accelerate bone repair and peri-implant bone formation and increase bone contact ratios, bone volume fraction (bone volume/total volume), trabecular number, and trabecular thickness. Only two clinical studies examined the effect of EMF on pain and swelling after dental implant surgery, with one finding that subjects exposed to EMF used analgesics fewer times and in far lower doses than the control group and the other finding no significant difference in reducing these outcomes between the groups. Conclusion: Overall, devices that deliver non-ionizing low-level EMF can be a viable and widely recognized non-invasive adjuvant therapy for attaining success and better outcomes after dental implant surgery due to their efficacy, safety, and short exposure time.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA