Low-intensity Magnetic Field Research Articles

Nanobots: An endodontist saviour.

The application of nanoparticles in the form of solution for irrigation, medication and as an additive for sealer/restorative material has been evaluated to improve the antibacterial efficacy in the field of endodontics. Recently developed nanobots are injected into the teeth to destroy pathogens and they are more effective in root canal therapy. They are helical shaped and composed of silicon dioxide with iron embedded into the silica body to provide magnetic properties. They are also able to move within the dentinal tubules and are manipulated peripherally through a low-intensity magnetic field. These nanobots can be administered into the cleaned central canal of a tooth samples which are immersed in deionized water and their motions are monitored using a near-infrared imaging technique to produce heat which is a hyperthermia-based bactericidal method which help to eradicate the surrounding pathogens.

Prediction of simultaneous enhancement of Goos-Hänchen shift and reflectance in VO2 grating structure

Vanadium dioxide (VO2) material stands out in the family of the phase change materials due to its temperature-dependent phase transition properties, which make it a promising candidate for the temperature-dependent optoelectronic devices. Enhancement of the Goos-Hänchen (GH) shift is essential in VO2-based nanostructures for their applications, but it has been limited to the multilayered structures with VO2 materials so far. Here, we theoretically investigate the GH shift and corresponding reflectance in the VO2-based grating structure. We evidence that this structure has two GH peaks (3107λ and 2266λ) and high reflectance values (both up to 1) when VO2 is in the insulating phase as well as the maximum GH valley (−1061λ) and low reflectance (0.19) when VO2 is in the metallic phase. The electromagnetic field distributions in this hybrid structure suggest that the guided mode resonances (GMRs) can be excited no matter whether VO2 is in its insulating or metallic phases due to the couplings between the incident waves and the adjacent evanescent diffracted order waves, which produces their enhanced GH shifts. Different from the former case with the high reflectances and the large GH shifts, the latter has the low maximum magnetic field intensity due to the lossy property of the metallic VO2, which leads to the low reflectance and small GH valley value. Additionally, we have also found that by the alterations of the temperature-dependent conductivity of VO2 and the geometric parameters of the structure allows for the control the magnitude and position of the GH peak or valley. The simultaneously enhanced GH shifts and reflectances in the VO2-based grating structure, associated with its controllable features, enable it an effective configuration for establishing the temperature sensors and optoelectronic switches.

Spectroscopic detection of chromatin uncoiling and chromosome alignment in neuronal-like cells under exposure to low intensity magnetic fields

In this manuscript we reported the results of our studies concerning the response of vibration bands in deoxyribonucleic acid region in neuronal-like cells under exposure to static and 50 Hz electromagnetic fields using Fourier Transform Infrared spectroscopy. This technique was chosen because it is able to detect alteration of vibration bands of chemical compounds even induced by small stress agents. The aim of this study was to investigate the response of chromatin and chromosome to low intensity electromagnetic fields at values similar to manmade electromagnetic fields. The phosphate bands of asymmetric and symmetric stretching mode (representative of deoxyribonucleic acid spectral region) were observed to decrease after 3 h exposure at 1 mT (both static and 50 Hz magnetic field). Prolonging time exposure or increasing the intensity of applied magnetic field induced a low increasing in intensity of these vibration bands. This finding can be explaining assuming that chromatin uncoiling occurred at low intensity of the field and that increasing time exposure or magnetic field intensity caused an increasing of the torque on chromosome inducing an alignment along the direction of the field.

Contactless magnetically responsive injectable hydrogel for aligned tissue regeneration

Cellular alignment plays a pivotal role in several human tissues, including skeletal muscle, spinal cord and tendon. Various techniques have been developed to control cellular alignment using 3D biomaterials. However, the majority of 3D-aligned scaffolds require invasive surgery for implantation. In contrast, injectable hydrogels provide a non-invasive delivery method, gaining considerable attention for the treatment of diverse conditions, including osteochondral lesions, volumetric muscle loss, and traumatic brain injury.We engineered a biomimetic hydrogel with magnetic responsiveness by combining gellan gum, hyaluronic acid, collagen, and magnetic nanoparticles (MNPs). Collagen type I was paired with MNPs to form magnetic collagen bundles (MCollB), allowing the orientation control of these bundles within the hydrogel matrix through the application of a remote low-intensity magnetic field. This resulted in the creation of an anisotropic architecture. The hydrogel mechanical properties were comparable to those of human soft tissues, such as skeletal muscle, and proof of the aligned hydrogel concept was demonstrated.In vitro findings confirmed the absence of toxicity and pro-inflammatory effects. Notably, an increased fibroblast cell proliferation and pro-regenerative activation of macrophages were observed. The in-vivo study further validated the hydrogel biocompatibility and demonstrated the feasibility of injection with rapid in situ gelation. Consequently, this magnetically controlled injectable hydrogel exhibits significant promise as a minimally invasive, rapid gelling and effective treatment for regenerating various aligned human tissues.

Fillable Magnetic Microrobots for Drug Delivery to Cardiac Tissues In Vitro.

Many cardiac diseases, such as arrhythmia or cardiogenic shock, cause irregular beating patterns that must be regulated to prevent disease progression toward heart failure. Treatments can include invasive surgery or high systemic drug dosages, which lack precision, localization, and control. Drug delivery systems (DDSs) that can deliver cargo to the cardiac injury site could address these unmet clinical challenges. Here, a microrobotic DDS that can be mobilized to specific sites via magnetic control is presented. This DDS incorporates an internal chamber that can protect drug cargo. Furthermore, the DDS contains a tunable thermosensitive sealing layer that gradually degrades upon exposure to body temperature, enabling prolonged drug release. Once loaded with the small molecule drug norepinephrine, this microrobotic DDS modulated beating frequency in induced pluripotent stem-cell derived cardiomyocytes (iPSC-CMs) in a dose-dependent manner, thus simulating drug delivery to cardiac cells in vitro. The DDS also navigates several maze-like structures seeded with cardiomyocytes to demonstrate precise locomotion under a rotating low-intensity magnetic field and on-site drug delivery. This work demonstrates the utility of a magnetically actuating DDS for precise, localized, and controlled drug delivery which is of interest for a myriad of future opportunities such as in treating cardiac diseases.

Robust Algorithms for the Analysis of Fast-Field-Cycling Nuclear Magnetic Resonance Dispersion Curves

Fast-Field-Cycling (FFC) Nuclear Magnetic Resonance (NMR) relaxometry is a powerful, non-destructive magnetic resonance technique that enables, among other things, the investigation of slow molecular dynamics at low magnetic field intensities. FFC-NMR relaxometry measurements provide insight into molecular motion across various timescales within a single experiment. This study focuses on a model-free approach, representing the NMRD profile R1 as a linear combination of Lorentzian functions, thereby addressing the challenges of fitting data within an ill-conditioned linear least-squares framework. Tackling this problem, we present a comprehensive review and experimental validation of three regularization approaches to implement the model-free approach to analyzing NMRD profiles. These include (1) MF-UPen, utilizing locally adapted L2 regularization; (2) MF-L1, based on L1 penalties; and (3) a hybrid approach combining locally adapted L2 and global L1 penalties. Each method’s regularization parameters are determined automatically according to the Balancing and Uniform Penalty principles. Our contributions include the implementation and experimental validation of the MF-UPen and MF-MUPen algorithms, and the development of a “dispersion analysis” technique to assess the existence range of the estimated parameters. The objective of this work is to delineate the variance in fit quality and correlation time distribution yielded by each algorithm, thus broadening the set of software tools for the analysis of sample structures in FFC-NMR studies. The findings underline the efficacy and applicability of these algorithms in the analysis of NMRD profiles from samples representing different potential scenarios.

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.

Experimental investigation into the implications of low-intensity magnetic field treatment on the structural and functional properties of rapeseed meal during biofermentation

The functionality of rapeseed meal is limited, to acquire more utilization, the functional attributes were improved by altering its structural features using magnetic field-assisted solid fermentation. The magnetic treatment was performed every 24 h (specifically at 24, and 48 h), each treatment having a duration of 4 h. The magnetic intensity was set at 120 Gs, and the fermentation temperature 37 °C. Magnetic field-assisted solid fermentation resulted in higher surface hydrophobicity, fluorescence intensity, UV absorption, and sulfhydryl groups of rapeseed meal. Magnetic field treatment considerably enhanced solubility, antioxidant activity, emulsifying activity, and stability by 8.8, 19.5, 20.7, and 12.3 %, respectively. Magnetic field-assisted solid fermentation also altered rapeseed meal structure, as shown by scanning electron microscopy, atomic force microscopy, and Raman spectroscopy outcomes. Correlation analysis displayed positive interrelationships between functional characteristics, and surface hydrophobicity, β-sheets, and polydispersity index.

Nonmetallic graphite for tumor magnetic hyperthermia therapy

Magnetic hyperthermia therapy (MHT) has garnered immense interest due to its exceptional spatiotemporal specificity, minimal invasiveness and remarkable tissue penetration depth. Nevertheless, the limited magnetothermal heating capability and the potential toxicity of metal ions in magnetic materials based on metallic elements significantly impede the advancement of MHT. Herein, we introduce the concept of nonmetallic materials, with graphite (Gra) as a proof of concept, as a highly efficient and biocompatible option for MHT of tumors in vivo for the first time. The Gra exhibits outstanding magnetothermal heating efficacy owing to the robust eddy thermal effect driven by its excellent electrical conductivity. Furthermore, being composed of carbon, Gra offers superior biocompatibility as carbon is an essential element for all living organisms. Additionally, the Gra boasts customizable shapes and sizes, low cost, and large-scale production capability, facilitating reproducible and straightforward manufacturing of various Gra implants. In a mouse tumor model, Gra-based MHT successfully eliminates the tumors at an extremely low magnetic field intensity, which is less than one-third of the established biosafety threshold. This study paves the way for the development of high-performance magnetocaloric materials by utilizing nonmetallic materials in place of metallic ones burdened with inherent limitations.

8-Oxoguanine-DNA-Glycosylase Gene Polymorphism and the Effects of an Alternating Magnetic Field on the Sensitivity of Peripheral Blood.

The production of reactive oxygen species (ROS) in animals and cells often results from exposure to low-intensity factors, including magnetic fields. Much of the discussion about the initiation of oxidative stress and the role of ROS and radicals in the effects of magnetic fields has centered on radical-induced DNA damage. The DNA concentration in the final solution was determined spectrophotometrically. Typing of the polymorphic variant rs1052133 of the 8-oxoguanin DNA glycosylase (hOGG1) gene was performed by polymerase chain reaction. An enzyme immunoassay was performed to determine the level of 8-oxyguanine in DNA. To process samples exposed to an alternating magnetic field, the authors developed a device for the automated study of biological fluids in an alternating magnetic field. The content of hydrogen peroxide in aqueous solutions of DNA was determined using the spectrophotometric method. It was experimentally determined that an increase in the concentration of hydrogen peroxide in an aqueous medium by 3-5 times under the action of a low-frequency magnetic field reduces the resistance of the genomic material to oxidative modification and the accumulation of 8-oxyguanine in DNA. A model is proposed for the mechanism of action of a low-frequency magnetic field on aqueous solutions of nucleic acids and proteins, which satisfies the model of a chemical oscillator for the transformations of reactive oxygen species in an aqueous medium. The model illustrates the oscillating nature of the processes occurring in an aqueous solution of DNA and makes it possible to predict changes in the concentration of hydrogen peroxide in an aqueous solution of biopolymers, depending on the frequency of the acting low-intensity magnetic field. The key element in the mechanisms involved in the effects of low-intensity magnetic field on living systems is the occurrence of ROS generation in the aquatic environment of chemical oscillators, in which the competition of physical and chemical processes (electron transfers, reactions of decay and addition of radicals, spin magnetically induced conversion, synthesis, and decay of the longest-lived form-hydrogen peroxide) is controlled by a magnetic field.

Instant water toxicity detection based on magnetically-constructed electrochemically active biofilm

Water toxicity determination with electrochemically active bacteria (EAB) is promising in the early warning of water pollution. However, limited by tedious biofilm formation, natural EAB biofilms are uncapable of the instant detection of water toxicity, resulting in the failure for the emergency monitoring of water pollution. To solve this problem, a novel method for the rapid construction of EAB biofilms using magnetic adsorption was established, and the performance of instant water toxicity detection with magnetically-constructed EAB biofilm was investigated. The results demonstrate that EAB biofilms were magnetically constructed in less than 30 min, and magnetically-constructed EAB biofilm generated stable currents even under continuous flow conditions. Magnetically-constructed EAB biofilms realized instant water toxicity detection, and the sensitivity increased with the decrease of magnetic field intensity. Low magnetic field intensity resulted in a loose biofilm structure, which is conducive to toxic pollutant penetration. The detection limit for Cu2+, phenol, and Cd2+ achieved 0.07 mg/L with optimal magnetic field intensity, and the detection time was less than 30 min. This study broadens the application of water toxicity determination with EAB, and establishes a foundation for the instant and continuous detection of water toxicity with EAB.

Three-dimensional investigation of capturing particle considering particle-RBCs interaction under the magnetic field produced by an Halbach array

In the present study, a 3D model of capturing carrier particles in a branched vessel under a non-uniform magnetic field produced by a Halbach array is investigated. The effect of different parameters including blood velocity, particle diameter, distance from the center of magnet to the center of vessel, and the interaction force is investigated. Results show that particle diameter, magnetic intensity, and the blood velocity have respectively the maximum effect on Capture Efficiency (CE). For instance, by increasing the particle diameter from 250nm to 2000nm, CE is increased by nearly 96%. Besides, it was observed that by considering the interaction forces, the computation time is increased by nearly 2.5 times. It was concluded that for low particle diameter, high blood velocity, and low magnetic field intensity, the interaction force has negligible effect on the CE of nanoparticles and can be neglected for the sake of time-saving.

Апоптоз лимфоцитов при воздействии комбинации физических факторов

The article presents the comparative study results of the bioeffects of 30-minute exposure session to electromagnetic radiation with 1000 MHz frequency and 10 mW/cm2 EFD; of 30-minute exposure session to low-frequency pulsed magnetic field with 4 mT magnetic induction, as well as their combination, on rat’s lymphocytes apoptosis level in vivo. The apoptosis level was assessed morphologically with fluorescent microscope after 24-hours of cell suspension cultivation at immunological plates at 37 0C in nutrient medium without loading. The percentage of cells with morphological signs of apoptosis (margination, condensation and fragmentation of chromatin in nucleus) was quantitatively determined. It was found that electromagnetic irradiation had no significant impact on apoptosis level, but magnetic field action resulted in reducing the apoptosis cells number by 16% (p≤0,01) compared to the control group. The combination of electromagnetic radiation and low intensity magnetic field increased the apoptotic cells number by 28% (p ≤0.01) compared to the control. Thus, the mediated effect of electromagnetic radiation on blood cells genome leads to disruption of its normal functioning. It has been shown that low-frequency magnetic field can influence on intracellular processes in different directions; in combination with electromagnetic radiation it can intensify pathological reactions, and thus launching the apoptosis massive program.

Three-dimensional investigation of capture efficiency of carrier particles in a Y-shaped vessel considering non-Newtonian models

In the present study, the capture efficiency (CE) and trajectories of carrier particles in a Y-shaped vessel under the effect of a non-uniform magnetic field are investigated in three dimensions. The magnetic field is produced by a cylindrical Neodymium Iron Boron (NdFeB) magnet located outside the lower branch. Two cases are considered for the magnet: (1) magnet with zero rotation and (2) 90° rotated with double height. Two non-Newtonian models, i.e., Power-law and Carreau, are considered to model blood behavior. The effect of magnetic field intensity, blood velocity, particle diameter, and magnet positioning for all three cases, one Newtonian and two non-Newtonian models, is investigated. Besides, the effect of magnetic field and non-Newtonian models on the wall shear stress (WSS) was investigated. The results showed that increasing the blood velocity and particle diameter resulted in enhanced CE. Also, by increasing the particle diameter from 500 nm to 1500 nm, the CE for Newtonian, Power-law, and Carreau models enhanced by 74 %, 90 %, and 81 %, respectively. It was found that non-Newtonian behavior and magnetic field would increase the WSS; however, its effect on the WSS can be neglected for low magnetic field intensity. The 90° rotated with double height is the most desirable case for capturing the carrier particles.

Magnetic Prospection in the Eastern Lower City of Artashat-Artaxata in the Ararat Plain of Armenia

In March of 2021, the Berlin-based company cmp continued geophysical prospection works at the ancient city of Artashat-Artaxata (Ararat Province, Armenia). The city was founded by Artashes-Artaxias I in the early 2nd century BC and served as his capital. First magnetic measurements were conducted by the Eastern Atlas company in September 2018. In 2021, during the 5-day survey a total surface of approximately 19.5 ha was investigated by use of the LEA MAX magnetic gradiometer array. This system was configured with seven fluxgate gradiometer probes, similar to the system used in the first survey of 2018. The investigated areas of the Eastern Lower City of Artaxata, located to the south of the investigated field of 2018, had good surface conditions with a moderate amount of sources causing disturbance. However, the general level of the magnetic gradient values measured was significantly lower compared to the 2018 data. Despite the lower magnetic field intensity, a continuation of linear structures towards the south was observed. These lines, most likely reflecting streets and pathways, criss-cross the central part of the Eastern Lower City in a NW–SE and NE–SW direction and exhibit partly positive, partly negative magnetic anomalies. Attached to them, some isolated spots with building remains were identified. The negative linear anomalies point to remains of limestone foundations, as detected in the northern part of the Lower City. The low magnetic intensity and fragmentation of the observed structures are most likely due to severe destruction of the ancient layers by 20th-century earthworks for agricultural purposes. Moreover, the southern part of the surveyed area was affected by major changes caused by modern quarries at Hills XI and XII. In general, the results of the two magnetic prospection campaigns greatly aid our understanding of the archaeological situation in the area of the Eastern Lower City of Artaxata, justifying further investigations that will surely contribute to greater contextualization of the identified archaeological structures. The full data sets are also published in open access on Zenodo.

In Vivo Modification of Microporous Structure in Bacterial Cellulose by Exposing Komagataeibacter xylinus Culture to Physical and Chemical Stimuli.

Bacterial cellulose (BC) samples were obtained in a static culture of K. xylinus under the effect of a low-intensity magnetic field, UV light, NaCl, and chloramphenicol. The effect of such stimuli on the amount of BC produced and its production rate, specific area, pore volume, and pore diameter were evaluated. The polysaccharide production was enhanced 2.28-fold by exposing K. xylinus culture to UV light (366 nm) and 1.7-fold by adding chloramphenicol (0.25 mM) to the medium in comparison to BC control. All the stimuli triggered a decrease in the rate of BC biosynthesis. BC membranes were found to be mesoporous materials with an average pore diameter from 21.37 to 25.73 nm. BC produced under a magnetic field showed the lowest values of specific area and pore volume (2.55 m2 g−1 and 0.024 cm3 g−1), while the BC synthesized in the presence of NaCl showed the highest (15.72 m2 g−1 and 0.11 cm3 g−1). FTIR spectra of the BC samples also demonstrated changes related to structural order. The rehydration property in these BC samples is not mainly mediated by the crystallinity level or porosity. In summary, these results support that BC production, surface, and structural properties could be modified by manipulating the physical and chemical stimuli investigated.

Transcranial Magnetic Stimulation: New Sapience into How Brain Stimulation Palliates Symptoms of PTSD

Posttraumatic stress disorder (PTSD) is a chronic, often debilitating psychological state disorder that may develop after a traumatic life event. Most patients get over the initial symptoms naturally, but those that experience persistent symptoms require standard treatment approaches such as 1: 1 psychotherapy, psychotropic medications, or both whichever have relevance. However, there are secondary hindrances such as drug safety and drug tolerability associated with these psychotropic medications, that interdict an appropriate course of treatment. The upshot of those events is that it creates a breach in our potential to properly manage PTSD in a significant number of patients, leaving them endangered to surfacing complications like employment-related incapacities, suicidal ideations, co-morbid medical disorders, and illicit drug abuse. Thus, there is a need for more worthwhile, tolerable, and long-standing approaches. Transcranial magnetic stimulation may be a safe and non-invasive treatment technique used to treat various psychiatric and neurological disorders. This neuromodulation technique involves stimulation of specific deep brain regions by the assembly of high and low-intensity magnetic fields thus filling the therapeutic void. This text mainly focuses on the results of controlled and pragmatic trials for efficacy, safety, and tolerability of patients affected by PTSD. The alternative treatment for PTSD currently is psychotherapy and antidepressant medications.Despite receiving these alternatives, there are about 50% of patients who continue to experience major symptoms..That is, the reason why TMS came out as another suitable option. Atleast 5 directories such as MEDLINE, CINAHL, Psych INFO, SCOPUS and EMBASE were probed to pinpoint pragmatic studies and randomized controlled trials that were designed for the treatment of PTSD with TMS. A total of 28 studies were found worthy for this review, out of which 5 are mentioned in this article. Although, so far it looks propitious in spite of the manifoldness as far as its outcomes and its clinical importance are concerned. Hence, still researches involving stimulation constraints are to be conducted in the near future.

Application of ground magnetics and geoelectrical methods in delineating sulphide deposit in oshiri area, southeastern nigeria

The Asu River Group Shale in the Oshiri area was evaluated using ground magnetic and geoelectrical methods within existing mine. Some exploration programs in the area have resulted to failure due to the fact that project managers have not fully understood the use and importance of geophysics in enhancing the search for mineral deposits. The aim of the study was to delineate the sulphide deposits using ground magnetics and geoelectrical methods. Result of the ground magnetic survey delineated some shallow tectonic structures like fractures and faults which are capable of hosting metallic sulphide deposits. The residual magnetic intensity of the study area indicates very low magnetic field intensities around the central and southern portions of the study area. These low values indicate absence of magnetite in the near surface materials as suggested by previous studies in the area, but could be referred to as zones with shallow tectonic structures which could be faults and/or fractures capable of housing sulphide deposits. The ore-bearing veins within the sedimentary rocks have susceptibilities of ≤ -1.8 nT. The low, negative residual susceptibility zone in the southeastern portion of the study area was targeted for the induced polarization IP and electrical resistivity tomography. Four traverses of induced polarization IP and resistivity surveys were carried out with all the profile lines were in the NE-SW direction. Isolated chargeable bodies with values greater than 340msec and a correspondingly low resistivity values (10Ωm-50Ωm), were encountered across some of these profiles. This zone may represent zones with sulphide mineralization. These identified chargeable bodies occur at approximate depth and width range of between 25-30m and 50-70m respectively. The 1D stratigraphic models reveal an average thickness estimate of 11.0m. Using scalar geometric approach, an estimate of 103,513.75tonnes was obtained, representing a relatively economically viable quantity and a worthy target for investors.

Therapeutic Potential of Low-Intensity Magnetic Field Stimulation in 6-Hydroxydopamine Rat Model of Parkinson's Disease: From Inflammation to Motor Function.

Parkinson's disease (PD) is a progressive neurodegenerative disorder that mainly affects the aged population. Transcranial magnetic field (MF) stimulation has shown to provide temporary motor recovery in neurological disorders. The aim of this study was to understand the cellular and molecular mechanism of low-intensity MF stimulation (17.96 µT; 50Hz; 2 h/day, four weeks) in a rat model of severe PD. A clinically relevant, bilateral striatal 6-hydroxydopamine (6-OHDA) lesioned rat model of severe PD was employed to test the efficacy of low-intensity MF stimulation in the management of motor symptoms. The mechanism of action of MF was dissected by assessing the microglial activation, tissue ultrastructure, and cerebrospinal fluid (CSF) metabolomics using microdialysis. We observed a significant improvement in the postural balance and gait after MF exposure with a significant reduction in the number of activated microglia. There was an improvement in striatal dopaminergic innervation and glutamate levels but it did not reach a level of statistical significance. MF stimulation helped ameliorate the motor deficits and reduced inflammation but was unable to provide a significant change in terms of dopaminergic innervation and metabolic profile in the severe 6-OHDA PD rat model.

Effect of the magnetic field on the operation of ionisation gauges

Hot cathode ionisation gauges are the only reliable pressure measurement devices suitable for both high and ultra-high vacuum measurement. These devices are characterized by low accuracy that is hardly better than 20%. The sources of loss of accuracy are documented in the literature although their quantification and details are not fully understood. In the present work, simulations of Bayard-Alpert and extractor gauges were performed under the influence of uniform magnetic fields up to 30 Gs. Results are in qualitative agreement with measurements taken previously with the Bayard-Alpert gauge. Both gauges are sensitive to low intensity magnetic fields which may be present in vacuum chambers. However, the extractor gauge proved to be more stable in the presence of a magnetic field due to its ring-shaped cathode.