Static Magnetic Field Intensity Research Articles

Static magnetic field contributes to osteogenic differentiation of hPDLSCs through the H19/Wnt/β-catenin axis

BackgroundStatic magnetic field (SMF) as an effective physical stimulus is capable of osteogenic differentiation for multiple mesenchymal stem cells, including human periodontal ligament stem cells (hPDLSCs). However, the exact molecular mechanism is still unknown. Therefore, this study intends to excavate molecular mechanisms related to SMF in hPDLSCs using functional experiments. MethodshPDLSCs were treated with different intensities of SMF, H19 lentivirus, and Wnt/β-catenin pathway inhibitor (XAV939). Changes in osteogenic markers (Runx2, Col Ⅰ, and BMP2), Wnt/β-catenin markers (β-catenin and GSK-3β), and calcified nodules were examined using RT-qPCR, western blotting, and alizarin red staining in hPDLSCs. ResultsSMF upregulated the expression of H19, and SMF and overexpressing H19 facilitated the expression of osteogenic markers (Runx2, Col Ⅰ, and BMP2), activation of the Wnt/β-catenin pathway, and mineralized sediment in hPDLSCs. Knockdown of H19 alleviated SMF function, and treatment with XAV939 limited SMF- and H19-mediated osteogenic differentiation of hPDLSCs. Notably, the expression of hsa-miR-532-3p, hsa-miR-370-3p, hsa-miR-18a-5p, and hsa-miR-483-3p in hPDLSCs was regulated by SMF, and may form an endogenous competitive RNA mechanism with H19 and β-catenin. ConclusionSMF contributes to the osteogenic differentiation of hPDLSCs by mediating the H19/Wnt/β-catenin pathway, and hsa-miR-532-3p, hsa-miR-370-3p, hsa-miR-18a-5p, and hsa-miR-483-3p may be the key factors in it.

Low-intensity magnetization pretreatment to enhance biomethane generation and the abundance of key microorganisms for anaerobic digestion of sewage sludge

This work explores the impact of static magnetic field (SMF) intensity on biomethane production from anaerobic digestion (AD) of sewage sludge. Two different SMF intensities (20 mT and 1.5 T) were applied to magnetize the sludge destined to the AD process. The magnetic pretreatment at 20 mT was particularly effective, as it increased biomethane production by 12.7 % compared to the control test. On the contrary, exposing the sludge to 1.5 T adversely affected biomethane production, resulting in a 15.1 % decrease. The positive correlation observed between low-intensity SMF exposure and enhanced biomethane yield, in contrast to the inhibitory effect of high-intensity SMF, suggests the existence of an optimal intensity threshold within the lower range for maximizing methane production. The impact of magnetic pretreatment on the anaerobic microbial community was investigated through high-throughput sequencing analysis of magnetized sludge samples. This approach enabled the identification of specific shifts in microbial populations associated with SMF exposure, thereby elucidating the role of SMF in modulating key microbial communities for the AD process. The findings of this study provide insights into the potential mechanisms underlying these responses and underscore the potential of SMF application for improving the anaerobic valorization of sewage sludge.

Experimental and numerical study on single ice crystal growth of deionized water and 0.9 % NaCl solution under static magnetic field

Ice crystal growth of water and its aqueous solution is the key phenomenon in food freezing. In this research, the effect of static magnetic field (SMF) on single ice crystal growth was investigated combing experiment and simulation. The ice crystal growth of water and NaCl-water solution under 0 - 15 mT SMF intensities were studied. The UV absorbance of water after SMF treatment was measured. Phase field model was adopted to simulate the ice crystal growth. The results show that SMF significantly inhibited the growth rate, while had little effect on the morphology and growth direction of ice crystals. SMF had a certain enhancement effect on the UV absorbance of deionized water. The proposed model could well simulate the ice crystal growth under different SMF intensities. Combining experimental and simulation results, it can be inferred that SMF inhibits ice crystal growth by enhancing original hydrogen bonds and reducing free energy.

Design of a Permanent Magnet Electromagnetic Acoustic Transducer (EMAT) for In-Situ Inspection of Metals at high Temperatures

In this proposed research, a permanent magnet longitudinal wave Electromagnetic Acoustic Transducer (EMAT) was designed for In-Situ inspection of metals at high temperatures. A permanent magnet EMAT generates Lorentz force inside metals by the interaction of magnetic fields and eddy currents. As temperature rises, various factors can influence the intensity of the Lorentz force, making it difficult to produce and detect ultrasonic waves. Thus, it is essential to optimize the sensor at ambient temperature before attempting to generate a reliable signal at elevated temperatures. The challenge highlighted has been addressed by optimizing the intensity of static field by varying the parameter like spacing between magnets that are being used. In order to minimize the effects of elevated temperatures, the sensor's stability has been enhanced by the implementation of efficient insulating measures. Furthermore, Finite Element (FE) simulations were conducted under on aluminium sample. These simulation results were then compared to experimental data to validate the efficiency of the designed sensor. Keywords: Permanent magnet, EMAT, Lorentz force, ultrasonic waves, high temperature, static magnetic field intensity.

Design of guided wave magnetostrictive patch transducer with vertical static bias magnetic field for pipe inspection

Compared with electromagnetic acoustic transducer (EMAT), magnetostrictive patch transducer (MPT) has higher energy conversion efficiency. MPT is often used to excite and receive long-distance ultrasonic guided waves for defect detection or structural health monitoring of large industrial equipment. In this work, a new design method of permanent magnet MPT using the vertical static bias magnetic field to excite shear horizontal (SH) guided waves is proposed. First, the mathematical model of exciting ultrasonic guided waves by a vertical static bias magnetic field MPT is established, and the equivalent surface stress in the magnetostrictive patch is calculated. It is shown that the vertical static bias magnetic field MPT can excite SH guided waves in plates. Then, the influence of static bias magnetic field intensity on the amplitude of guided wave signal is analyzed. Compared with other traditional MPTs, the amplitude of SH guided wave signal excited by the vertical static bias magnetic field MPT is increased. Finally, a periodic permanent magnet (PPM)-MPT with a central frequency of 120 kHz is designed. The proposed PPM-MPT improves the energy conversion efficiency compared to the circumferential alternating permanent magnet array type MPT. The PPM-MPT can detect defects in a steel pipe with a wall thickness of 3.5 mm and an inner diameter of 100 mm. The results show that the PPM-MPT designed in this paper successfully detects the through hole with a diameter of 2 mm, and the cross-section loss rate of the defect is about 0.6 %.

Study on the Role of Physical Fields in TMAS to Modulate Synaptic Plasticity in Mice.

Transcranial magneto-acoustic stimulation (TMAS) is a composite technique combining static magnetic and coupled electric fields with transcranial ultrasound stimulation (TUS) and has shown advantages in neuromodulation. However, the role of these physical fields in neuromodulation is unclear. Synaptic plasticity is the cellular basis for learning and memory. In this paper, we varied the intensity of static magnetic, electric and ultrasonic fields respectively to investigate the modulation of synaptic plasticity by these physical fields. There are control, static magnetic field (0.1 T/0.2 T), TUS (0.15/0.3 MPa), and TMAS (0.15 MPa + 0.2 V/m, 0.3 MPa + 0.2 V/m, 0.3 MPa + 0.4 V/m) groups. Hippocampal areas were stimulated at 5 min daily for 7 days and in vivo electrophysiological experiments were performed. TMAS induced greater LTP, LTD, and paired-pulse ratio (PPR) than TUS, reflecting that TMAS has a more significant modulation in both long- and short- term synaptic plasticity. In TMAS, a doubling of the electric field amplitude increases LTP, LTD and PPR to a greater extent than a doubling of the acoustic pressure. Increasing the static magnetic field intensity has no significant effect on the modulation of synaptic plasticity. This paper argues that electric fields should be the main reason for the difference in modulation between TMAS and TUS and that changing the amplitude of the electric field affected the modulation of TMAS more than changing the acoustic pressure. This study elucidates the roles of the physical fields in TMAS and provides a parameterisation way to guide TMAS applications based on the dominant roles of the physical fields.

Bond Integrity and Microleakage of Orthodontic Bands Cemented by Glass Ionomer Cements Stored in Static Magnetic Field

Aim: Improving the band-tooth bond integrity by glass ionomer cement (GIC) is essential in orthodontic treatments. As, microleakage under bands induced enamel demineralization. Storing the dental material to updated magnets improved their mechanical properties. This research aimed to assess the microleakage of GIC after storing in a static magnetic field (SMF). Material and Methods: Forty premolars and their suitable bands were randomly classified into two main groups according to the types of GIC tested in this research; resin-modified GIC (RMGIC) and conventional GIC (CGIC). Each group was subdivided according to the exposure to SMF before polymerization into two subgroups. CGIC not exposed to SMF (CC), CGIC exposed to SMF (CM), RMGIC not exposed to SMF (LC) and RMGIC exposed to SMF (LM). SMF intensity performed was 0.225 Tesla, exposed for 48 hours at room temperature. The entire tube of RMGIC was inserted in SMF, where the powder of CGIC was stored in SMF. The microleakage under the band was evaluated under a 20× stereomicroscope by dye penetration technique at the cement band interface. Wilcoxon signed-rank test was used for data analysis, p ≤ .05. Results: The main (SD) microleakage of GIC reduced significantly ( p = .043) after being exposed to SMF from 3.1950 (0.632) mm to 1.7095 (0.1176) mm and from 0.8745 (0.1104) mm to 0.6430(0.094) mm for CGIC and RMGIC, respectively. Conclusion: Storing the CGIC powder in (0.225 T) SMF improves band-tooth bond integrity. Additionally, the preservation of RMGIC in SMF minimized the microleakage under orthodontic bands.

Alginate/GelMA microparticles via oil-free interface shearing for untethered magnetic microbots.

Microrobots hold broad application prospects in the field of precision medicine, such as intravenous drug injection, tumor resection, opening blood vessels and imaging during abdominal surgery. However, the rapid and controllable preparation of biocompatible hydrogel microparticles still poses challenges. This study proposes the one-step direct acquisition of biocompatible sodium alginate and gelatin methacrylate (GelMA) hydrogel microparticles using an oil-free aqueous solution, ensuring production with a controllable generation frequency. An adaptive interface shearing platform is established to fabricate alginate/GelMA microparticles using a mixture of the hydrogel, photoinitiator, and Fe3O4 nanoparticles (NPs). By adjusting the static magnetic field intensity (Bs), vibration frequency, and flow rate (Q) of the dispersed phase, the size and morphology of the hydrogel microparticles can be controlled. These hydrogel microparticle robots exhibit magnetic responsiveness, demonstrating precise rotating and rolling movements under the influence of an externally rotating magnetic field (RMF). Moreover, hydrogel microparticle robots with a specific critical frequency (Cf) can be customized by adjusting the Bs and the concentration of Fe3O4 NPs. The directional in situ untethered motion of the hydrogel microparticle robots can be successfully realized and accurately controlled in the climbing over obstacles and in vitro experiments of animals, respectively. This versatile and fully biodegradable microrobot has the potential to precisely control movement to bone tissue and the natural cavity of the human body, as well as drug delivery.

Effects of static magnetic field-assisted freezing on physicochemical indices and bacterial communities of shrimp (Penaeus vannamei)

To inhibit the melanization of shrimp (Penaeus vannamei) and improve its freezing quality, different intensities of static magnetic field (MF) were used to assist freezing, with MF intensities of 0, 2, 4, 6, and 8 mT. The effects of different freezing treatments on the freezing parameters, microstructure, enzyme activities, quality indicators, and bacterial communities were investigated. The results indicated that the phase transition and total freezing time significantly decreased under the action of 2 mT MF (8.4% and 15.4%, p < 0.05). Meanwhile, 2 mT treatment significantly reduced polyphenol oxidase and Ca2+-ATPase activities (45.2% and 99.1%), drip loss (46.0%), color change (24.4% and 20.9%), myofibril fragmentation index (20.4%), thiobarbituric acid reactive substances (30.6%) and total viable count (24.2%) (p < 0.05); improved hardness and chewiness (32.2% and 33.3%) (p < 0.05); and protected muscle microstructure compared to common freezing. Isolation and examination of pathogenic bacteria revealed that the 2 mT MF significantly reduced the number of Vibrio parahaemolyticus (50.3%) (p < 0.05). High-throughput sequencing analysis also demonstrated that a 2 mT magnetic field is preferable for assisting in the freezing process of Penaeus vannamei. It effectively decreases the microbial richness and diversity of shrimp, along with the abundance of spoilage bacteria such as Vibrio and Pseudoalteromonas.

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.

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.

Estimation of the shear bond strength and adhesive remnant index of orthodontic adhesives stored in static magnetic field

ABSTRACT Purpose Static magnetic field (SMF) affects the polymerization reaction of orthodontic adhesives. Although their effects on shear bond strength (SBS) and adhesive remnant index (ARI) are not investigated yet, the current research designed to search the impact of storage of the orthodontic composite on SMF on SBS and ARI. Materials and Methods Biofix and Heliosit orthodontic adhesives were employed in this study, beside 60 extracted premolars that were separated into two equal groups according to adhesive type. Each group, furtherly, is divided into three subgroups (10 each) according to the storage field magnetic intensity as Zero, 225 and 1000Gauss. The tensile instron machine was performed to debond the brackets after incubation for 24 h in a dark wet environment at 37C°. ARI was evaluated by stereomicroscope at 20 magnification power. SBS and ARI data were analysed by ANOVA and Kruskal–Wallis tests, respectively. P was set at 0.05. The results SBS of Heliosit adhesive significantly increased with elevation of field intensity at 8.5496, 9.7592 and 11.2129MPas, while Biofix SBS was significantly changed from 9.1547, 11.8294 and 8.7132MPas with Zero, 225 and 1000Gauss field intensity, respectively. ARI showed a non-significant difference at three storage intensities as p = 0.543, 0.377 for Biofix and Heliosit, respectively. Conclusion Storage of Biofix and Heliosit orthodontic adhesives in 225Gauss SMF improves SBS. Furthermore, an increase in SMF intensity up to 1000Gauss improves Heliosit SBS, unlike Biofix which shows significant reduction.

Static magnetic field exposure improved the volatile composition and aroma attribute of fresh-cut flower mushrooms (Lentinus edodes (Berk) sing)

Aroma attribute and aroma compound (AOC) composition of fresh-cut flower mushrooms under different static magnetic field (SMF) intensities (2 mT, 4 mT, 6 mT, and 8 mT) were evaluated via coupling aroma sensory assessment and headspace-gas chromatography-ion mobility spectrometry with principal component analysis and partial least squares-relationship analysis. Results showed that aroma quality was severely loss after dicing treatment. A total of 43 AOCs were identified from flower mushrooms, and 3-octanone was the predominant compound. Application of 2 mT SMF maintained more acceptable raw mushroom-like, earthy/musty, and almond-like/roasted, and cooked cabbage-like aroma attributes of diced samples, related to maximally retaining the contents of the key AOCs (i.e. 3-octanone, 2-methylbutanal, and dimethyl trisulfide). These findings could provide a technical reference and theoretical basis for improving the aroma quality of fresh-cut mushrooms via magnetic fields and explain the mechanism of aroma enhancement.

Effects of 0.4 T, 3.0 T and 9.4 T static magnetic fields on development, behaviour and immune response in zebrafish (Danio rerio)

Magnetic Resonance Imaging (MRI) is widely applied in medical diagnosis due to its excellent non-invasiveness. With the increasing intensity of static magnetic field (SMF), the safety assessment of MRI has been ongoing. In this study, zebrafish larvae were exposed to SMFs of 0.4, 3.0, and 9.4 T for 2 h (h), and we found that there was no significant difference in the number of spontaneous tail swings, heart rate, and body length of zebrafish larvae in the treatment groups. The expression of development-related genes shha, pygo1, mylz3 and runx2b in the three SMF groups was almost not significantly different from the control group. Behavior tests unveiled a notable reduction in both the average speed and duration of high-speed movements in zebrafish larvae across all three SMF groups. In addition, the 0.4 and 3.0 T SMFs increased the migration of neutrophils in caudal fin injury, and the expression of pro-inflammatory cytokines was also increased. To explore the mechanism of SMFs on zebrafish immune function, this study utilized aanat2−/− mutant fish to demonstrate the effect of melatonin (MT) involvement in SMFs on zebrafish immune function. This study provides experimental data for understanding the effects of SMFs on organisms, and also provides a new insight for exploring the relationship between magnetic fields and immune function.

Enhancing anammox nitrogen removal by static magnetic field exposure: Performance, microbial community and symbiotic relationship analysis

Anammox batch reactors were operated with different static magnetic field (SMF) intensities (0 mT, 40 mT, and 100 mT). The impacts of SMF and the influent nitrogen concentration on nitrogen removal were analyzed. Sludge characteristics, microbial community structure, and metabolism pathways were explored. The results show that a high nitrogen load greatly decreased the nitrogen removal efficiency. Still, applying SMF with appropriate intensity enhanced the nitrogen removal performance, especially under high nitrogen loading conditions. Systems with 40 mT SMF at normal nitrogen loading conditions had the highest total nitrogen removal efficiency. In contrast, a higher SMF intensity was conducive to the anammox process with a high nitrogen load. Candidatus Kuenenia was fast enriched under high nitrogen loading conditions in the control systems. However, Candidatus Brocadia was more abundant than Ca. Kuenenia in the systems with SMF application. SMF was the main factor affecting the microbial metabolism, enhancing the metabolic pathways related to bacterial growth and resistance to environmental stress. The metabolic interactions between the anammox bacteria and other bacteria were enhanced by applying SMF to the anammox process, especially for the cross-feeding of cofactors and vitamins in the anammox consortia.

Magnetic Field-Dependent Microstructure Evolution of Solidified Co39.2Ni39.2Al21.6 Eutectic Medium-Entropy Alloy

A (Fe, Cr)-free Co39.2Ni39.2Al21.6 eutectic medium-entropy alloy (EMEA) was designed and fabricated to study the microstructure and its evolution during slow solidification under different intensities of high static magnetic field (0 T, 5 T and 10 T). It was found that the original microstructure was characterized by FCC/BCC mixed herringbone eutectics consisting of two types of lamellar structures: a curved and wormy anomalous eutectic in the fringe, and a straight and long regular eutectic in the center. Nano-sized L10-type martensite layers are also distributed on the BCC lamellar as the martensitic transformation product. The FCC and BCC phases were enriched in Co and Al elements, respectively, while Ni element was distributed homogenously in both phases. With increasing magnetic field intensity, the herringbone eutectic structures remained stable, without the formation of a primary phase, while the phase constitution and the orientation relationships in the eutectic structures remained unchanged, with no obvious magnetically induced alignments. However, the lamellar spacing of the regular lamellar eutectic decreased significantly from 3.3 μm (0 T) to 1.93 μm (10 T); by contrast, the volume fraction of the anomalous eutectics increased considerably from 28.35% (0 T) to 55.14% (10 T), and the assumption that the imposed convection and destabilization of lamellar eutectics is controlled by the magnetic field is discussed in depth. Our results show a great potential for tailoring microstructures and properties by applying a strong magnetic field during the solidification process of EMEAs.

Promoting the densification and grain refinement with assistance of static magnetic field in laser powder bed fusion

Owing to its high accuracy and good design flexibility, the application of laser powder bed fusion (LPBF) to metallic parts has been rapidly increasing. However, the parts fabricated using LPBF exhibit high porosity and rough texture, which severely hinders the development of this technology. In this study, typical Al-based (AlSi10Mg) and Ni-based (Inconel 718) alloys were fabricated under a wide range of parameter spaces using static magnetic field (SMF) of up to 0.2 T. The experimental results showed that the fabricated parts had a higher density with SMF than the samples fabricated without SMF. A comparison of the samples fabricated with and without SMF revealed that the SMF refined the grain size and improved the mechanical properties. Furthermore, physics-based models, including the Seebeck effect, heat transfer, and fluid flow, in melt pools dynamics were used to simulate the thermos-electric-magnetic (TEM) forces and flow patterns during LPBF. The results of the simulation suggest that at the melt pool scale, the depression zone depth increases with increasing SMF intensity, and the correspondingly increased laser absorptivity is the main reason for the decrease in the lack-of-fusion defects. In addition to the flow pattern change at the melt pool scale, the TEM force acting on the cellular dendrite also plays an important role in grain refinement, reaching 105 N/m3 under a SMF of 0.1 T. Furthermore, the results of the tensile tests showed an increase in the ultimate tensile strength and elongation of the printed samples under the applied SMF. The present study can guide the porosity control and the widening of the processing window in LPBF.

Static magnetic field assisted freezing of four kinds of fruits and vegetables: Micro and macro effects

Novel food freezing technology assisted by static magnetic field (SMF) has emerged in recent years. However, few papers have compared the effects of SMF on different kinds of foods under the same experimental conditions. This study investigated the effects of 0 to 45 mT SMF intensities on apple, peach, cucumber and Indian jujube from micro and macro scales. The parameters including ice crystal size, time through -1 ∼ -5 °C, drip loss and texture were compared. The results show that SMF tended to decrease the ice crystals size for four kinds of fruits and vegetables, and the optimal SMF intensity varied with the types of foods. The beneficial effect of SMF on reducing ice crystal size did not always appear in macro-scale freezing. Positive effects of SMF on macro-scale parameters only appeared in Indian jujube, and stronger intensity brought better quality.

Impact of static magnetic field on electron transport and microbial community shifts in the nitritation sequencing batch reactor

To reveal the influence mechanisms of static magnetic field on the nitritation process from new perspectives of electron transport and microbial community shift, a static magnetic field-enhanced nitritation SBR process was employed, and the pollutant removals, the hydroxylamine oxidoreductase activity, the cytochrome c content, as well as the electron transport system activity of the activated sludge, were determined while the static magnetic field intensity was reduced from 40 mT to 0 mT via 20 mT and 10 mT. Meanwhile, the microbial community structure was examined. When the static magnetic field intensity was 10 mT, and the concentrations of COD and ammonium nitrogen in influent were 196.42 ± 5.19 mg/L and 96.99 ± 0.53 mg/L respectively, the nitrite accumulation rate was 93.56 ± 1.19%, meanwhile, the highest hydroxylamine oxidoreductase activity, cytochrome c content, and electron transport system activity which were 15.879 ± 0.055 U/mg MLVSS, 0.086 ± 0.001 mg/g MLVSS and 0.288 ± 0.005 μg O2/g·min respectively were obtained. Moreover, the abundance of Nitrosomonas sp. was much higher than those while the intensities were 40 mT, 20 mT and 0 mT. Static magnetic field can accelerate the start-up of the nitritation process, moreover, improve the performance of the process by changing the microbial community structure and improving the HAO activity, the Cyt c content, ETSA, as well as the energy generation of microorganisms.

Impact of the Lorentz force on electron track structure and early DNA damage yields in magnetic resonance-guided radiotherapy

Magnetic resonance-guided radiotherapy (MRgRT) has been developed and installed in recent decades for external radiotherapy in several clinical facilities. Lorentz forces modulate dose distribution by charged particles in MRgRT; however, the impact of Lorentz forces on low-energy electron track structure and early DNA damage induction remain unclear. In this study, we estimated features of electron track structure and biological effects in a static magnetic field (SMF) using a general-purpose Monte Carlo code, particle and heavy ion transport code system (PHITS) that enables us to simulate low-energy electrons down to 1 meV by track-structure mode. The macroscopic dose distributions by electrons above approximately 300 keV initial energy in liquid water are changed by both perpendicular and parallel SMFs against the incident direction, indicating that the Lorentz force plays an important role in calculating dose within tumours. Meanwhile, DNA damage estimation based on the spatial patterns of atomic interactions indicates that the initial yield of DNA double-strand breaks (DSBs) is independent of the SMF intensity. The DSB induction is predominantly attributed to the secondary electrons below a few tens of eV, of which energy deposition patterns are not considerably affected by the Lorentz force. Our simulation study suggests that treatment planning for MRgRT can be made with consideration of only changed dose distribution.