Effect Of Static Magnetic Field Research Articles

Thermoluminescence dosimetry (TLD) in a 3 T magnetic resonance imaging (MRI) environment: implications for personnel exposure monitoring.

Thermoluminescent dosimeters (TLDs) serve as compact and user-friendly tools for various applications, including personal radiation dosimetry and radiation therapy. This study explores the potential of utilizing TLD-100 personal dosimetry, conventionally applied in PET/CT (positron emission tomography/computed tomography) settings, in the PET/MRI (magnetic resonance imaging) environment. The integration of MRI into conventional radiotherapy and PET systems necessitates ionizing radiation dosimetry in the presence of static magnetic fields. In this study, TLD-100 dosimeters were exposed on the surface of a water-filled cylindrical phantom containing PET-radioisotope and positioned on the patient table of a 3 T PET/MRI, where the magnetic field strength is around 0.2 T, aiming to replicate real-world scenarios experienced by personnel in PET/MRI environments. . Results indicate that the modified MR-safe TLD-100 personal dosimeters exhibit no significant impact from the static magnetic field of the 3 T PET/MRI, supporting their suitability for personal dosimetry in PET/MRI settings. This study addresses a notable gap in existing literature on the effect of MRI static magnetic field on TLDs.

External static magnetic field mitigates nitrogen loss during agro-waste composting

Nitrogen is a crucial component in the composting process of agricultural waste and serves as a key nutrient source for organic fertilizer production. However, nitrogen loss during composting is inevitable, and how to retain it needs further investigation. The effects of static magnetic field on nitrogen conversion during agro-waste composting were explored. Results showed that low magnetic field intensity treatment reduced NH3 by 29.68% but raised N2O by 1.57%, while high intensity treatment reduced both NH3 and N2O by 3.51% and 4.35%, respectively. Pearson correlation analysis revealed that external static magnetic field regulated NH3 emission by affecting temperature, pH, electrical conductivity and NH4+-N, while modulated N2O emission by influencing moisture content, volatile solids, nxrA, nirK, norB, nosZ and NO2--N. The findings stated that external static magnetic field effectively reduced nitrogen loss, enhanced its retention and exhibited the potential to become an effective technical measure to promote nitrogen utilization during composting.

Analysis of the performance and microbial community of continuous dark fermentation combined with steady static magnetic field

The effect of external static magnetic field on hydrogen production and its mechanism were studied by continuous dark fermentation with no pretreatment excess sludge as inoculum. The results showed that under conditions of 37 ± 1 ℃, HRT 8h, OLR 15g/(L· d) and no control of influent pH, 78 mT external static magnetic field by adding magnets on both sides of the reactor could accelerate the enrichment of Ethanoligenens and improve the activity of reduced coenzyme I (96%), ferredoxin oxidoreductase (29%) and pyruvate: ferredoxin oxidoreductase (7%) so that the maximum hydrogen productivity could reach 1.657L H2/L, which was 5 times higher than that of non-magnetic group. Moreover, the n-caproic acid production could also increase due to the enrichment of carbon chain elongation microorganisms. The decline of hydrogen production was mainly due to hydrogenotrophic methanogenesis and acetic acid accumulation. This study was benefit to understand the interaction mechanism between magnetic field and microorganisms during the process of biological hydrogen production.

Effect of Static Magnetic Field on the Quality of Pork during Super-Chilling Storage.

Fresh pork tenderloin was stored at -3 °C under different static magnetic fields (SMF) of 0, 4, and 10 mT (control, MF-4, and MF-10) to investigate their physicochemical properties changes during storage of 8 days. The initial equilibrium temperature of the samples stored with 4 mT MF was found to be -2.3 °C, which was slightly lower (0.3 °C) than that the control value. The super-chilling phenomenon on the pork was then observed, as the samples stored under the magnetic field did not freeze throughout storage period, but the control experienced a sudden change in temperature after 138 h and then froze. The preservation effect of MF-4 on meat quality was the best in all treatment groups. MF-4 achieved a higher water-retention rate, with drip and cook losses of 6.5% and 29.0% lower than the control, respectively. Meanwhile, the MF-4 effectively delayed the color change in the meat during the storage and the texture hardening after cooking, and effectively controlled the growth of the total volatile saline nitrogen content on the samples. In addition, MF-4 delayed the reduction in myofibrillar protein solubility, sulfhydryl content, and emulsification capacity, indicating that this field inhibited the denaturation of myofibrillar protein. This study can be considered as an application reference of magnetic fields during meat storage at a super-chilled temperature.

Effect of Moderate Static Magnetic Fields on Mice Oocyte Vitrification: Calcium-Related Genes Expression.

The ability to cryopreserve oocytes without ultrastructural injury has been a concern in the development and use of methods to preserve female reproduction. The stability of the cell membrane must be preserved to reduce the damage caused by ice crystals during vitrification. One approach that has been explored is the use of static magnetic fields (SMFs), which are believed to influence cell membrane stability. In this study, the in vitro effects of SMF that range between 20-80 mT on the vitrification of mice germinal vesicle (GV) oocytes were studied. The viability and mitochondrial (Mt) membrane potential of both vitrified and nonvitrified oocytes were assessed using Trypan blue and JC1 staining. The high in vitro maturation (IVM) rate and high Mt membrane potential in metaphase II (MII) oocytes were taken into account to determine the optimal magnetic field intensity, that is, 20 mT. None of the SMF conditions resulted in intact spindles in MII oocytes. The study also explored the expression of store-operated calcium entry (Stim1, Orai1, and Ip3r) and meiosis resumption (Ccnb, Cdk) genes in GV and MII oocytes of both vitrified and control groups. The results show that the expressions of Orai1 and Ccnb genes in Vit-MII-SMF oocytes were considerably increased. However, no significant difference in Stim1 expression was observed between the groups. The Vit-MII-SMF group exhibited a significantly higher Ccnb expression compared to other groups. In vitro fertilization (IVF) was performed to evaluate the 2 pronuclear (2PN) rates. The findings demonstrated that using 20 mT SMF improved 2PN rates compared to the nonvitrified groups. This study provides a deeper understanding of the effects of moderate SMF and vitrification on the expression of calcium channel genes in GV and MII oocytes. The results suggest that applying a 20 mT SMF can help prevent cryoinjury and enhance the characteristics of vitrified-warmed oocytes.

Static Magnetic Field Stimulation Enhances Shunting Inhibition via a SLC26 Family Cl- Channel, Inducing Intrinsic Plasticity.

Magnetic fields are being used for detailed anatomical and functional examination of the human brain. In addition, evidence for their efficacy in treatment of brain dysfunctions is accumulating. Transcranial static magnetic field stimulation (tSMS) is a recently developed technique for noninvasively modifying brain functions. In tSMS, a strong and small magnet when placed over the skull can temporarily suppress brain functions. Its modulatory effects persist beyond the time of stimulation. However, the neurophysiological mechanisms underlying tSMS-induced plasticity remain unclear. Here, using acute motor cortical slice preparation obtained from male C57BL/6N mice, we show that tSMS alters the intrinsic electrical properties of neurons by altering the activity of chloride (Cl-) channels in neurons. Exposure of mouse pyramidal neurons to a static magnetic field (SMF) at a strength similar to human tSMS temporarily decreased their excitability and induced transient neuronal swelling. The effects of SMF were blocked by DIDS and GlyH-101, but not by NPPB, consistent with the pharmacological profile of SLC26A11, a transporter protein with Cl- channel activity. Whole-cell voltage-clamp recordings of the GlyH-101-sensitive Cl- current component showed significant enhancement of the component at both subthreshold and depolarized membrane potentials after SMF application, resulting in shunting inhibition and reduced repetitive action potential (AP) firing at the respective potentials. Thus, this study provides the first neurophysiological evidence for the inhibitory effect of tSMS on neuronal activity and advances our mechanistic understanding of noninvasive human neuromodulation.

Ion transport and gas collision effects in a radio frequency quadrupole cooler: installation in the Eltrap solenoid and beam calculations

Radio frequency quadrupole coolers (RFQCs) are very suitable to cool ion beams with moderate energy spread, typically ions of exotic nuclear species (like $^{132}$ Sn $^{1+}$ ) as in the Selective Production of Exotic Species project at the Laboratori Nazionali di Legnaro, whose ion source supplies 40 keV ions. Beam dynamics includes ion–gas collisions (with a balance of cooling and diffusion effects), acceleration and deceleration and radiofrequency confinement, which can be supplemented by static magnetic field effects. Insertion of a prototype RFQC in the solenoid of the Eltrap machine is also discussed here, with innovations in beam extraction and in modelling, now also based on stochastic equations. Practical consideration on gas pumping and voltage distribution are also included. Typical limits of RFQC are discussed, with special attention to the extracted beam root mean square emittance, which is shown to strongly depend not only on cooler parameters, but also on extraction optics.

Meta-analysis of static magnetic field effects on blood and bone tissue: A comprehensive review

Meta-analysis of static magnetic field effects on blood and bone tissue: A comprehensive review

An Investigation Into the Effect of Different Static Magnetic Fields of 1.5-T and 3.0-T MRI on the Measurement of Tumor Diameters in Breast Cancer.

Objective This study aimed to determine whether differences in the static field strength of 1.5-T and 3.0-T MRI systems affect the diagnostic results of tumor size measurement in breast cancer and to compare them with the results of tumor size in surgical pathology diagnosis. Methods We adopted aretrospective and case-controlstudy design. We included patients with a suspected or confirmed diagnosis of breast cancer who underwent breast MRI at our hospital between January 2017 and March 2023. Diffusion-weighted imaging (DWI), gadolinium-enhanced T1-weighted (Gd-T1WI) MRI, and tumor size from surgical pathology were compared via a significance difference test and correlation analysis between the two groups. In this study, the maximum diameters of the tumor obtained by DWI and Gd-T1WI on 1.5-T and 3.0-T MRI systems were divided by the maximum diameter fromsurgical pathology diagnosis to arrive at the tumor ratio index. Results A total of 36 patients met the selection criteria: 15 for the 1.5-T system and 21 for the 3.0-T system; all of them were female. The mean ratio of pathological tumor length to diameter measured by MRI for each system showed no significant difference between the groups (p=0.653). For the 1.5-T MRI system, the ratio of tumor length diameter by DWI to that by pathology was 1.042 ±0.361, and the ratio of tumor length diameter by Gd-T1WI to that by pathology was 1.107 ±0.314, with no significant difference observed between ratios (p=0.345). The correlation coefficient between them was r=0.730 (p=0.002). For the 3.0-T MRI system, the ratio of tumor length diameter by DWI to that by pathology was 0.893 ±0.197, while the ratio of tumor length diameter by Gd-T1WI to that by pathology was 1.062 ±0.177, with a significant difference between the two (p<0.001). The correlation coefficient between the two groups was 0.695 (p<0.001). Conclusions While there was no significant difference in the ratios of tumor length diameter measured by 1.5-T Gd-T1WI and DWI compared to pathology, there was a significant difference in the ratios of tumor length diameter measured by 3.0-T DWI and Gd-T1WI compared to pathology. Hence, only 3.0-T DWI can lead to a potential underestimation of tumor length.

Effect of static magnetic field on the molten pool dynamics during laser powder bed fusion of Inconel 718 superalloy

Recent researches show that a static magnetic field (SMF) has an impact on the molten pool dynamics and microstructure of laser powder bed fusion (L-PBF). This work is intended to the multiple effect of SMF on the molten pool dynamics during L-PBF of Inconel 718 superalloy. A three-dimensional (3D) multiphase computational fluid dynamics (CFD) model at the powder-bed scale was established by coupling the electromagnetic braking and Seebeck effect in a static vertically-distributed magnetic field. Results show that the magnetic damping force (MDF) of the order of 104 N/m3∼105 N/m3 within the whole molten pool suppresses the Marangoni convection. The thermoelectric magnetic force (TEMF) of the order of 106 N/m3∼107 N/m3 rotates in the mushy zone and further enhances the melt flow of the whole molten pool. The SMF will not transform the flow pattern and temperature distribution in the molten pool. SMFs of 0.1 T and 0.3 T will suppress the melt flow, while that of 0.5 T will enhance the melt flow. The width of molten pool first decreases and then increases when the magnetic flux density (MFD) increases from 0 T to 0.5 T. In addition, applying a SMF of 0.3 T can effectively inhibit pore defect and spatters. This work can provide insight into the control of molten pool by introducing a SMF during L-PBF.

Effects of static magnetic field on the sulfate metabolic pathway involved in Magnetospirillum magneticum AMB-1 cell growth and magnetosome formation.

Magnetotactic bacteria (MTB) can use their unique intracellular magnetosome organelles to swim along the Earth's magnetic field. They play important roles in the biogeochemical cycles of iron and sulfur. Previous studies have shown that the applied magnetic fields could affect the magnetosome formation and antioxidant defense systems in MTB. However, the molecular mechanisms by which magnetic fields affect MTB cells remain unclear. We aim to better understand the dark at 28°C-29°C for 20 h, as shownthe interactions between magnetic fields and cells, and the mechanism of MTB adaptation to magnetic field at molecular levels. We performed microbiological, transcriptomic, and genetic experiments to analyze the effects of a weak static magnetic field (SMF) exposure on the cell growth and magnetosome formation in the MTB strain Magnetospirillum magneticum AMB-1. The results showed that a 1.5 mT SMF significantly promoted the cell growth but reduced magnetosome formation in AMB-1, compared to the geomagnetic field. Transcriptomic analysis revealed decreased expression of genes primarily involved in the sulfate reduction pathway. Consistently, knockout mutant lacking adenylyl-sulfate kinase CysC did no more react to the SMF and the differences in growth and Cmag disappeared. Together with experimental findings of increased reactive oxidative species in the SMF-treated wild-type strain, we proposed that cysC, as a key gene, can participate in the cell growth and mineralization in AMB-1 by SMF regulation. This study suggests that the magnetic field exposure can trigger a bacterial oxidative stress response involved in AMB-1 growth and magnetosome mineralization by regulating the sulfur metabolism pathway. CysC may serve as a pivotal enzyme in mediating sulfur metabolism to synchronize the impact of SMF on both growth and magnetization of AMB-1.

Effect of static magnetic field pretreatment on the structure and oil absorption properties of normal maize starch

In this work, we report the effect of static magnetic field (SMF) on normal maize starch (NMS) structure and oil absorption properties. The results showed that the untreated NMS had the total oil absorption of 83.90%, solubility of 19.00%, swelling power of 20.32 g/g, and amylose content of 26.95%. Besides, compared with untreated NMS, pretreatment with different SMF strengths significantly reduced the total oil absorption (61.78–78.12%), solubility (16.99–18.61%), swelling power (17.62–19.02 g/g), and amylose content (19.77–24.73%) of NMS. Besides, the SMF-pretreated NMS had a rough surface with more pits and pores, a denser particle structure, and a smaller specific surface area and particle size than untreated NMS. However, the high SMF intensity (50 mT) made NMS form a porous structure, leading to the highest oil absorption of NMS (78.12%), but still less than untreated NMS (83.90%). FT-IR, XRD, and DSC studies further showed that SMF pretreatment improved the structural ordering and thermal stability of NMS particles, inhibiting the oil absorption of NMS. To investigate whether SMF pretreatment could reduce starch-based fried food oil absorption, LF-NMR was used to determine the oil content of fried NMS treated with different SMF strengths. Results indicated the oil content of NMS after frying was significantly reduced by SMF pretreatment than untreated NMS, and the lowest was 0.2751 g/g for SMF-30. Therefore, SMF pretreatment can effectively reduce the oil absorption capacity of NMS before and after frying and serve as a prospective technology to reduce the oil content of starch-based fried foods.

Moderate static magnetic field promotes fracture healing and regulates iron metabolism in mice

BackgroundFractures are the most common orthopedic diseases. It is known that static magnetic fields (SMFs) can contribute to the maintenance of bone health. However, the effect and mechanism of SMFs on fracture is still unclear. This study is aim to investigate the effect of moderate static magnetic fields (MMFs) on bone structure and metabolism during fracture healing.MethodsEight-week-old male C57BL/6J mice were subjected to a unilateral open transverse tibial fracture, and following treatment under geomagnetic field (GMF) or MMF. The micro-computed tomography (Micro-CT) and three-point bending were employed to evaluate the microarchitecture and mechanical properties. Endochondral ossification and bone remodeling were evaluated by bone histomorphometric and serum biochemical assay. In addition, the atomic absorption spectroscopy and ELISA were utilized to examine the influence of MMF exposure on iron metabolism in mice.ResultsMMF exposure increased bone mineral density (BMD), bone volume per tissue volume (BV/TV), mechanical properties, and proportion of mineralized bone matrix of the callus during fracture healing. MMF exposure reduced the proportion of cartilage in the callus area during fracture healing. Meanwhile, MMF exposure increased the number of osteoblasts in callus on the 14th day, and reduced the number of osteoclasts on the 28th day of fracture healing. Furthermore, MMF exposure increased PINP and OCN levels, and reduced the TRAP-5b and β-CTX levels in serum. It was also observed that MMF exposure reduced the iron content in the liver and callus, as well as serum ferritin levels while elevating the serum hepcidin concentration.ConclusionsMMF exposure could accelerate fracture healing via promote the endochondral ossification and bone formation while regulating systemic iron metabolism during fracture healing. This study suggests that MMF may have the potential to become a form of physical therapy for fractures.

The Influences of Micro-Alloying Element Sn and Magnetic Field on the Microstructure Evolution of Al–Bi Immiscible Alloys

An investigation was conducted through directional solidification experiments to explore the impact of micro-alloying element Sn and a magnetic field on the solidification behavior of immiscible Al–Bi alloys, as well as the combined effect of Sn and the magnetic field. Experimental results show that the size distribution of the dispersed particles in the low-speed solidified Al–3.4 wt.%Bi alloy presents two peaks, while it only shows one peak when solidified at a relatively high speed. The addition of Sn not only can enhance the nucleation rate and the number density of the Bi-rich droplets in the sample, but also decrease the Marangoni migration velocity and the axial resultant velocity of minority phase droplets in front of the solidification interface. Thereby it promotes the formation of Al–Bi alloys with a well-dispersed microstructure. A static magnetic field with the strength of 0.2 T increases the number density of the dispersed particles and decreases the average size and the size distribution width of the dispersed particles. Under the effect of Sn addition and static magnetic field, the average radius of the dispersed particles R and the solidification velocity V0 satisfy R∝V0−1/3 when the alloy was solidified at a relatively low velocity, R and V0 satisfy R∝V0−1/2 when the alloy is solidified at a high velocity.

Static magnetic field improvement of the quality of rice dumpling subjected to freeze–thaw cycles: Roles of phase transition of water and changes in structural and physicochemical properties of glutinous rice flour

This study aimed to investigate the effect of static magnetic field (SMF, 0–10 mT) on the quality of rice dumplings subjected to 7, 14, 21, and 28 freeze–thaw cycles. The underlying mechanism was explored by monitoring changes in water phase transition, water distribution, and structural and physicochemical properties of rice flour. Results suggested that SMF enables the formation of small ice crystals by accelerating freezing rate, shortening phase transition time, and increasing bound water content, which attributes to reducing the mechanical damage on starch granules and thus improves the quality of frozen rice dumpling. After 7–28 freeze–thaw cycles, SMF treatment increased the whiteness by 0.08–1.58, reduced the cracking ratio by 1.67 %–8.34 %, decreased the water loss ratio by 0–0.75 %, and significantly improved the texture of cooked rice dumplings. This study confirmed the feasibility of SMF in improving the quality of rice dumpling, which contributes to expanding the applications of magnetic freezer in the preservation of starch-based foods.

Effects of static magnetic field on vascular function and structure and their potential implications with redox regulation of actin cytoskeleton

Effects of static magnetic field on vascular function and structure and their potential implications with redox regulation of actin cytoskeleton

Examination of Thinning Inspection Method for Ferromagnetic Steel Tubes Using Velocity Effect of Static Magnetic Field

The high-speed movement of an electromagnetic sensor comprising static excitation and detection coils in a steel tube generates an eddy current in the tube. The presence of a defect in the steel tube may be detected via changes in the eddy current. In general, the ferromagnetic heat transfer tubes in oil and chemical plants are inspected for defects by moving an internally inserted electromagnetic sensor at a high speed of 1 m/s. Although previous studies have focused on the detection of localized thinning in the steel tube, there are no reports on a wide range of thinning in the steel tube. Therefore, this study investigated a thickness measurement method for a wide range of thinning in the steel tube using only static magnetic field. Consequently, the possibility of measuring the thickness in the steel tube based on the flux density inside the detection coil of the proposed static magnetic inspection sensor moving at 1 m/s was demonstrated. The flux density in the steel tube was evaluated by the three-dimensional nonlinear finite element method considering the velocity effect.

Multi-frequency and wide-angle nonreciprocity arising from non-uniform magnetic field

We investigate the effect of non-uniform external static magnetic field on the scattering nonreciprocity of a deep-subwavelength gyrotropic particle system. Based on a scattering matrix approach, we show analytically that asymmetrical extinction cross section of the scattering system for opposite illumination directions can be accessed at multi-frequency and wide-angle regimes, in the presence of magnetic field with weak spatial non-uniformity. A simplified dual-dipole model is further employed to capture the generic physics of nonreciprocal scattering, essentially attributed to the asymmetrical magneto-electric cross interactions. In addition, typical examples are provided with full-wave numerical verifications. Our finding may open a straightforward and efficient pathway to manipulate nonreciprocal scattering at the subwavelength scale.

Electrokinetic properties of healthy and β-thalassemia erythrocyte membranes under in vitro exposure to static magnetic field

Introduction: The current understanding of the biological impacts of a static magnetic field (SMF) is restricted to the direct interactions of the magnetic field with biological membranes. The electrokinetic (zeta) potential is an electrochemical property of erythrocyte surfaces which was negatively charged in physiological media after SMF exposure (0.1‒2.0 T).Methods: The novel data about electrokinetic parameters of the erythrocytes is determined by microelectrophoresis after SMF-exposure in norm and heterozygous β-thalassemia. The methods of light scattering, lipid peroxidation, fluorescence microscopy are used.Results: The electrokinetic potential of erythrocytes in norm is increased after SMF intensities due to enhanced negatively exposed charges on the outer surface of the membrane accompanied by an increase in light scattering where changes in cell morphology are observed. Conversely, a decrease in the zeta potential of β-thalassemia erythrocytes upon SMF-treatment was determined because of the reduction in the surface electrical charge of the membranes, where a significant decrease in light scattering at 1.5 T and 2.0 T was recorded. Exposure to SMF (0.5–2.0 T) was associated with an increase in the malondialdehyde content in erythrocytes. Biophysical studies regarding the influence of SMF on the electrostatic free energy of cells shows an increase in negative values in healthy erythrocytes, which corresponds to the implementation of a spontaneous process. This is also the process in β-thalassemia cells after SMF exposure with lower negative values of free electrostatic energy than erythrocytes in norm.Discussion: The effect of static magnetic field (SMF 0.1–2.0 T) on the electrokinetic and morphological characteristics of erythrocytes in norm and β-thalassemia is determined and correlated with the increase/reduction in surface charge and shrinkage/swelling of the cells, respectively. Lipid peroxidation of healthy and β-thalassemia erythrocytes caused an enhancement of lipid peroxidation because of the higher concentrations of TBARS products in cellular suspension. SMF (0.1‒2.0 T) altered the spontaneous chemical processes with negative values of electrostatic free energy of erythrocytes in norm and β-thalassemia accompanied by a lower FITC-Concanavalin A binding affinity to membrane receptors (SMF 2.0 T). The electrokinetic properties of human erythrocytes in norm and β-thalassemia upon SMF treatment and their interrelationship with the structural-functional state of the membrane were reported. The presented work would have future fundamental applications in biomedicine.

Unveiling the mechanism of static magnetic field effects on carbon flux into polyhydroxyalkanoate synthesis by Haloferax mediterranei

The high cost of polyhydroxyalkanoate (PHA) production significantly limits the large-scale industrial production of PHA. In this regard, applying static magnetic field (SMF) to increase PHA productivity could be a novel approach. The study explored the biological magnetic effects of H. mediterranei for PHA production. A magnetic window for PHA synthesis was found under 110 mT SMF, at which the PHA volumetric productivity increased by 27.28% compared with the control group. The carbon flux in the pathway from acetyl-CoA to the PHA synthesis increased while the flux to the TCA cycle decreased. Combined with transcriptome and proteome analysis, the key genes pdhA2, Paaj, and AccA in the PHA synthesis pathway were up-regulated, while gltA in the TCA cycle was down-regulated under 110 mT SMF. This study revealed the mechanism of SMF enhancement on PHA synthesis by H. mediterranei, which provides an effective solution to increasing PHA volumetric productivity.