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Bioelectromagnetics Sep 2021Magnetic field treatments of seeds have shown significant effects on the enhancement of crop growth. Soil moisture stress is the major constraint in the production of...
Magnetic field treatments of seeds have shown significant effects on the enhancement of crop growth. Soil moisture stress is the major constraint in the production of the sunflower crop. Therefore, the experiment was conducted to investigate the effect of a 200 mT magnetic field for 2 h on crop growth, and yield of sunflower crops raised from magnetically treated seeds sown under different moisture stress conditions. Results showed that plants from magnetically treated seeds had higher leaf area index, shoot length, number of leaves, chlorophyll content, biomass, 1000-seed mass, and seed yield as compared with untreated. Radiation use efficiency and water productivity were significantly higher in plants raised from magnetically treated seeds than untreated seeds. Crop raised from magnetically treated seeds had 6.2% more seed yield, 7.1% more protein, and oil content as compared with crops raised from untreated seeds. Hence, it may be concluded that exposure of dry sunflower seeds to the static magnetic field of 200 mT for 2 h could be used for improving crop growth and yield under different moisture stress conditions. © 2021 Bioelectromagnetics Society.
Topics: Chlorophyll; Helianthus; Magnetic Fields; Plant Leaves; Seeds
PubMed: 34174103
DOI: 10.1002/bem.22354 -
International Journal of Nanomedicine 2023Chemotherapy is the most prominent route in cancer therapy for prolonging the lifespan of cancer patients. However, its non-target specificity and the resulting... (Review)
Review
Chemotherapy is the most prominent route in cancer therapy for prolonging the lifespan of cancer patients. However, its non-target specificity and the resulting off-target cytotoxicities have been reported. Recent in vitro and in vivo studies using magnetic nanocomposites (MNCs) for magnetothermal chemotherapy may potentially improve the therapeutic outcome by increasing the target selectivity. In this review, magnetic hyperthermia therapy and magnetic targeting using drug-loaded MNCs are revisited, focusing on magnetism, the fabrication and structures of magnetic nanoparticles, surface modifications, biocompatible coating, shape, size, and other important physicochemical properties of MNCs, along with the parameters of the hyperthermia therapy and external magnetic field. Due to the limited drug-loading capacity and low biocompatibility, the use of magnetic nanoparticles (MNPs) as drug delivery system has lost traction. In contrast, MNCs show higher biocompatibility, multifunctional physicochemical properties, high drug encapsulation, and multi-stages of controlled release for localized synergistic chemo-thermotherapy. Further, combining various forms of magnetic cores and pH-sensitive coating agents can generate a more robust pH, magneto, and thermo-responsive drug delivery system. Thus, MNCs are ideal candidate as smart and remotely guided drug delivery system due to a) their magneto effects and guide-ability by the external magnetic fields, b) on-demand drug release performance, and c) thermo-chemosensitization under an applied alternating magnetic field where the tumor is selectively incinerated without harming surrounding non-tumor tissues. Given the important effects of synthesis methods, surface modifications, and coating of MNCs on their anticancer properties, we reviewed the most recent studies on magnetic hyperthermia, targeted drug delivery systems in cancer therapy, and magnetothermal chemotherapy to provide insights on the current development of MNC-based anticancer nanocarrier.
Topics: Humans; Hyperthermia, Induced; Drug Delivery Systems; Neoplasms; Magnetics; Magnetic Fields
PubMed: 37409027
DOI: 10.2147/IJN.S375964 -
Food Chemistry May 2023In this study, regulation mechanism of magnetic field on pectinase was investigated and it was preliminarily applied in postharvest sapodilla. Results indicated...
In this study, regulation mechanism of magnetic field on pectinase was investigated and it was preliminarily applied in postharvest sapodilla. Results indicated pectinase activity decreased by 44 % when treated by magnetic field (3 mT, 0.5 h) with kinetic parameters V/K decreasing from 0.799 to 0.366 min. The optimal temperature (48 °C) and pH (4.8) of pectinase was not altered by magnetic field but Ca at 0.05 mol/L strengthened its regulation effect. Ultraviolet and fluorescence spectra suggested tyrosine and tryptophan residues in treated pectinase became more hydrophobic while opposite in phenylalanine. CO, CNH, COO groups in pectinase were also influenced, resulting in decreased β-sheet (from 53 % to 49 %), increased random coil (from 20 % to 22 %) and β-turn content (from 27 % to 29 %). More importantly, the firmness of treated sapodilla remained 45 % of maximum at 12 days' storage. Our findings provided new insights to illustrate the role of magnetic field in fruit preservation.
Topics: Manilkara; Magnetic Fields; Polygalacturonase
PubMed: 36592602
DOI: 10.1016/j.foodchem.2022.135300 -
Nature Materials Sep 2022
Topics: Equipment Design; Magnetic Fields
PubMed: 36002723
DOI: 10.1038/s41563-022-01338-7 -
The European Physical Journal. E, Soft... Mar 2021The swimming of bacteria provides insight into propulsion and steering under the conditions of low-Reynolds number hydrodynamics. Here we address the magnetically...
The swimming of bacteria provides insight into propulsion and steering under the conditions of low-Reynolds number hydrodynamics. Here we address the magnetically steered swimming of magnetotactic bacteria. We use Stokesian dynamics simulations to study the swimming of single-flagellated magnetotactic bacteria (MTB) in an external magnetic field. Our model MTB consists of a spherical cell body equipped with a magnetic dipole moment and a helical flagellum rotated by a rotary motor. The elasticity of the flagellum as well as magnetic and hydrodynamic interactions is taken into account in this model. We characterized how the swimming velocity is dependent on parameters of the model. We then studied the U-turn motion after a field reversal and found two regimes for weak and strong fields and, correspondingly, two characteristic time scales. In the two regimes, the U-turn time is dominated by the turning of the cell body and its magnetic moment or the turning of the flagellum, respectively. In the regime for weak fields, where turning is dominated by the magnetic relaxation, the U-turn time is approximately in agreement with a theoretical model based on torque balance. In the strong-field regime, strong deformations of the flagellum are observed. We further simulated the swimming of a bacterium with a magnetic moment that is inclined relative to the flagellar axis. This scenario leads to intriguing double helical trajectories that we characterize as functions of the magnetic moment inclination and the magnetic field. For small inclination angles ([Formula: see text]) and typical field strengths, the inclination of the magnetic moment has only a minor effect on the swimming of MTB in an external magnetic field. Large inclination angles result in a strong reduction in the velocity in direction of the magnetic field, consistent with recent observations that bacteria with large inclination angles use a different propulsion mechanism.
Topics: Bacteria; Chemotaxis; Magnetic Fields; Models, Biological
PubMed: 33759003
DOI: 10.1140/epje/s10189-021-00038-5 -
Small (Weinheim An Der Bergstrasse,... Sep 2022The development of multifunctional and robust swimming microrobots working at the free air-liquid interface has encountered challenge as new manipulation strategies are...
The development of multifunctional and robust swimming microrobots working at the free air-liquid interface has encountered challenge as new manipulation strategies are needed to overcome the complicated interfacial restrictions. Here, flexible but reliable mechanisms are shown that achieve a remote-control bubble microrobot with multiple working modes and high maneuverability by the assistance of a soft air-liquid interface. This bubble microrobot is developed from a hollow Janus microsphere (JM) regulated by a magnetic field, which can implement switchable working modes like pusher, gripper, anchor, and sweeper. The collapse of the microbubble and the accompanying directional jet flow play a key role for functioning in these working modes, which is analogous to a "bubble tentacle." Using a simple gamepad, the orientation and the navigation of the bubble microrobot can be easily manipulated. In particular, a speed modulation method is found for the bubble microrobot, which uses vertical magnetic field to control the orientation of the JM and the direction of the bubble-induced jet flow without changing the fuel concentration. The findings demonstrate a substantial advance of the bubble microrobot specifically working at the air-liquid interface and depict some nonintuitive mechanisms that can help develop more complicated microswimmers.
Topics: Magnetic Fields; Microbubbles; Water
PubMed: 36045100
DOI: 10.1002/smll.202203872 -
Progress in Biophysics and Molecular... Jan 2023With the widespread use of static magnetic fields (SMFs) in medicine, it is imperative to explore the biological effects of SMFs and the mechanisms underlying their... (Review)
Review
With the widespread use of static magnetic fields (SMFs) in medicine, it is imperative to explore the biological effects of SMFs and the mechanisms underlying their effects on biological systems. The presence of magnetic materials within cells and organisms could affect various biological metabolism and processes, including stress responses, proliferation, and structural alignment. SMFs were generally found to be safe at the organ and organism levels. However. human subjects exposed to strong SMFs have reported side effects. In this review, we combined the magnetic properties of biological samples to illustrate the mechanism of action of SMFs on biological systems from a biophysical point of view. We suggest that the mechanisms of action of SMFs on biological systems mainly include the induction of electric fields and currents, generation of magnetic effects, and influence of electron spins. An electrolyte flowing in a static magnetic field generates an induced current and an electric field. Magnetomechanical effects include orientation effects upon subjecting biological samples to SMFs and movement of biological samples in strong field gradients. SMFs are thought to affect biochemical reaction rates and yields by influencing electron spin. This paper helps people how can harness the favorable biological effects of SMFs.
Topics: Humans; Magnetic Fields; Biophysics
PubMed: 36240898
DOI: 10.1016/j.pbiomolbio.2022.09.002 -
Scientific Reports Apr 2022This study evaluated the effect of the 1.5 T magnetic field of the magnetic resonance-guided linear accelerator (MR-Linac) on the radiation leakage doses penetrating...
This study evaluated the effect of the 1.5 T magnetic field of the magnetic resonance-guided linear accelerator (MR-Linac) on the radiation leakage doses penetrating the bunker radiation shielding wall. The evaluated 1.5 T MR-Linac Unity system has a bunker of the minimum recommended size. Unlike a conventional Linac, both primary beam transmission and secondary beam leakage were considered independently in the design and defined at the machine boundary away from the isocenter. Moreover, additional shielding was designed considering the numerous ducts between the treatment room and other rooms. The Linac shielding was evaluated by measuring the leakage doses at several locations. The intrinsic vibration and magnetic field were inspected at the proposed isocenter of the system. For verification, leakage doses were measured before and after applying the magnetic field. The intrinsic vibration and magnetic field readings were below the permitted limit. The leakage dose (0.05-12.2 µSv/week) also complied with internationally stipulated limits. The special shielding achieved a five-fold reduction in leakage dose. Applying the magnetic field increased the leakage dose by 0.12 to 4.56 µSv/week in several measurement points, although these values fall within experimental uncertainty. Thus, the effect of the magnetic field on the leakage dose could not be ascertained.
Topics: Magnetic Fields; Magnetic Resonance Imaging; Particle Accelerators; Protective Devices; Radiation Protection
PubMed: 35468983
DOI: 10.1038/s41598-022-10498-0 -
Lab on a Chip May 2021Precise manipulation of single particles is one of the main goals in the lab-on-a-chip field. Here, we present a microfluidic platform with "T" and "I" shaped magnetic...
Precise manipulation of single particles is one of the main goals in the lab-on-a-chip field. Here, we present a microfluidic platform with "T" and "I" shaped magnetic tracks on the substrate to transport magnetic particles and magnetized cells in a tri-axial time-varying magnetic field. The driving magnetic field is composed of a vertical field bias and an in-plane rotating field component, with the advantage of lowering the attraction tendency and cluster formation between the particles compared to the traditional magnetophoretic circuits. We demonstrate three fundamental achievements. First, all the particle movements are synced with the external rotating field to achieve precise control over individual particles. Second, single-particle and single living cell transport in a controlled fashion is achieved for a large number of them in parallel, without the need for a complicated control system to send signals to individual particles. We carefully study the proposed design and introduce proper operating parameters. Finally, in addition to moving the particles along straight tracks, transporting them using a ∼60° bend is demonstrated. The proposed chip has direct applications in the fields of lab-on-a-chip, single-cell biology, and drug screening, where precise control over single particles is needed.
Topics: Lab-On-A-Chip Devices; Magnetic Fields; Magnetics; Microfluidics
PubMed: 34008644
DOI: 10.1039/d1lc00097g -
Molecular Biology Reports Apr 2022Baicalin and baicalein have antioxidant, anti-inflammatory, hepatoprotective and anti-cancer properties. However, it is not known how a static magnetic field will modify...
BACKGROUND
Baicalin and baicalein have antioxidant, anti-inflammatory, hepatoprotective and anti-cancer properties. However, it is not known how a static magnetic field will modify these properties. Therefore, the aim of our study was to evaluate the simultaneous exposure of melanoma cells to flavones and the static magnetic fields that are generated by permanent magnets on the gene expression and the activity of the antioxidant enzymes that are associated with the antioxidant defense system.
METHODS AND RESULTS
Melanoma cells that had been treated with baicalin or baicalein were subjected to a static magnetic fields with a moderate induction. The static magnetic field was emitted by permanent magnets and the cell cultures were carried out in special test chambers. The research included determining the activity of the antioxidant enzymes (superoxide dismutase, glutathione peroxidase and catalase) as well as the gene expression profile. The addition of the flavones to the cell cultures at a concentration of 50 µmol/L resulted increase in the expression of the SOD1, SOD2 and GPX1 genes compared to the nontreated cell cultures. Simultaneous exposure of the melanoma cells to static magnetic field and baicalin or baicalein reduced their mRNA levels compared to the cultures to which only baicalin or baicalein had been added. The change in gene expression was accompanied by changes at the protein level associated with an increase in the activity of antioxidant enzymes.
CONCLUSION
We showed that baicalin or baicalein have anticancer properties by disturbing the redox homeostasis in melanoma cells and also increases the antioxidant system gene expression. There was also an antagonistic interaction between the studied flavones and the static magnetic field, which cause a decrease in the anticancer effects of baicalin or baicalein.
Topics: Cell Culture Techniques; Flavanones; Flavonoids; Humans; Magnetic Fields; Melanoma, Amelanotic; Skin Neoplasms
PubMed: 35059971
DOI: 10.1007/s11033-022-07148-z