Magnetic Needle Research Articles

Novel Use of Motor-Evoked Potential Monitoring During Magnetic Resonance Imaging-Guided Soft-Tissue Cryoablation: A Case Report

Motor-evoked potential (MEP) monitoring is an electrophysiologic technique useful for testing peripheral motor nerve integrity during cryoablation cases with risk of nerve injury. Previously, neuromonitoring within the magnetic resonance imaging (MRI) suite for cryoablation has not been performed as magnetic needles are used which could cause magnetic field interactions with neuromonitoring leads. We present the first report of a patient who underwent MEP monitoring during MRI-guided cryoablation of a vascular malformation adjacent to the brachial plexus. We demonstrate that MEPs may be safely and accurately performed by interleaving MRI and MEPs during treatment, reducing the risk of postprocedural complications.

Neuromuscular disease auxiliary diagnosis using a portable magnetomyographic system.

The measurement of electromyography (EMG) signals with needle electrodes is widely used in clinical settings for diagnosing neuromuscular diseases. Patients experience pain during needle EMG testing. It is significant to develop alternative diagnostic modalities. This paper proposes a portable magnetomyography (MMG) measurement system for neuromuscular disease auxiliary diagnosis. Firstly, the design and operating principle of the system are introduced. The feasibility of using the system for auxiliary diagnosis of neuromuscular diseases is then studied. The magnetic signals and needle EMG signals of thirty subjects were collected and compared. It is found that the amplitude of muscle magnetic field signal increases during mild muscle contraction, and the signal magnitudes of the patients are smaller than those of normal subjects. The diseased muscles tested in the experiment can be distinguished from the normal muscles based on the signal amplitude, using a threshold value of 6 pT. The MMG diagnosis results align well with the needle EMG diagnosis. In addition, the MMG measurement indicates that there is a persistence of spontaneous activity in the diseased muscle. The experimental results demonstrate that it is feasible to auxiliary diagnose neuromuscular diseases using the portable MMG system, which offers the advantages of non-contact and painless measurements. After more in-depth, systematic, and quantitative research, the portable MMG could potentially be used for auxiliary diagnosis of neuromuscular diseases.

Effect of magnetic needle magnetic particle grinding process on the performance of metal aluminum plates

Magnetic needle grinding processing technology is one of the magnetic grinding processing techniques. It possesses the characteristics of micro-cutting removal, small increase in processing temperature, flexible processing, high-quality, and high-precision processing. It is mainly utilized to remove burrs at the edge of the workpiece and the edge of the hole, as well as to finish the surface of the workpiece. It is frequently employed in civil, aerospace, navigation, and other fields. Due to the randomness and complexity of magnetic needle movement in magnetic abrasive finishing, it is difficult to quantify the processing parameters and predict processing effects. Therefore, this paper establishes a simulation model of magnetic needle in magnetic abrasive finishing by the coupling numerical simulation method of fluid dynamics discrete element method (CFD-DEM) to analyze the working state parameters of the magnetic needle. Through the simulation of actual working conditions, the machining process and parameters of magnetic abrasive finishing are quantified and analyzed, and the motion trend of magnetic needles during the machining process is studied. Then, the residual stress of single magnetic needle impact is analyzed with ABAQUS, and the performance enhancement of the workpiece is predicted. Finally, observations of surface morphology and validation of residual stress prediction were conducted through experiments on an aluminum plate. The results show that the residual stress of the aluminum plate is positively correlated with the number of strikes of the magnetic needle. The residual stress changes from tensile stress (+0.1 MPa) to compressive stress (-16.5 MPa). The comparison between simulation results and experimental results is good, indicating that the simulation model can comprehensively consider multiple factors such as magnetic field, particle motion, and fluid flow, and establish a magnetic needle magnetic grinding process model that is suitable for actual working conditions.

Digitized Continuous Magnetic Recordings for the August/September 1859 Storms From London, UK

AbstractDedicated scientific measurements of the strength and direction of the Earth's magnetic field began at Greenwich and Kew observatories in London, United Kingdom, in the middle of the nineteenth century. Using advanced techniques for the time, collimated light was focussed onto mirrors mounted on free‐swinging magnetized needles which reflected onto photographic paper, allowing continuous analog magnetograms to be recorded. By good fortune, both observatories were in full operation during the so‐called Carrington storm in early September 1859 and its precursor storm in late August 1859. Based on digital images of the magnetograms and information from the observatory yearbooks and scientific papers, it is possible to scale the measurements to International System of Units (SI units) and extract quasi‐minute cadence spot values. However, due to the magnitude of the storms, the periods of the greatest magnetic field variation were lost as the traces moved off‐page. We present the most complete digitized magnetic records to date of the 10‐day period from 25 August to 5 September 1859 encompassing the Carrington storm and its lesser recognized precursor on 28 August. We demonstrate the good correlation between observatories and estimate the instantaneous rate of change of the magnetic field.

Study on the effect of magnetic needle grinding process on the service properties of medical Mg-1.6Ca-2.0Zn alloy

Magnesium alloy, valued for its superior mechanical properties and biocompatibility in biomaterials, faces limitations such as rapid corrosion, poor wear resistance, and unfavorable cell adhesion. To address these challenges and enhance medical magnesium alloy development, this study investigates a magnetic needle grinding process on magnesium alloy. Mg-1.6Ca-2.0Zn alloy, prepared through powder metallurgy and T6 aging treatment, undergoes milling, and magnetic grinding using various needle sizes. The impact is assessed through Vickers hardness, residual stresses, surface roughness, friction and wear tests, electrochemical assessments, and contact angle tests. Results indicate a 22.59% microhardness increase, 30.43 MPa residual compressive stress, increased surface roughness, improved wear and corrosion resistance, and improved hydrophilia after magnetic needle grinding. This research provides a theoretical foundation for advancing medical magnesium alloy industrially.

Magnetic Resonance Imaging-Guided Needle Insertion Robots: A Review of Systems for Liver and Kidney Interventions

Magnetic Resonance Imaging-Guided Needle Insertion Robots: A Review of Systems for Liver and Kidney Interventions

Permanent magnet bias positioning magnetic needle for novel fluid magnetic mass transfer

Permanent magnet bias positioning magnetic needle for novel fluid magnetic mass transfer

Generation of sub-wavelength longitudinal magnetization needle and multiple longitudinal spots using circularly polarized beam through an annular walsh function filter

Generation of sub-wavelength longitudinal magnetization needle and multiple longitudinal spots using circularly polarized beam through an annular walsh function filter

Does needle positioning with magnetic field induction improve central venous catheterization performance by novice learners?

The novel ultrasound magnetic needle navigation technique can visualize the entire needle and identify its projected trajectory. We hypothesized that this technique increases the first-attempt success rate of central venous puncture by novice learners compared with the conventional needle navigation technique. This prospective, randomized, controlled trial with a crossover design included 50 participants with limited prior experience in US-guided procedures. Participants were randomly assigned to novel or conventional technique groups and asked to perform central venous cannulation in a phantom task trainer. After the first successful attempt, participants were allocated to the other technique group. Although participants in the novel technique group had a higher first-attempt success rate than did those in the conventional technique group, this difference was not statistically significant (p = 0.17). The total number of attempts also did not significantly differ (p = 0.16). The conventional technique group had more needle redirections (p = 0.01) and a longer time to successful cannulation (p = 0.01). The number of adverse effects (p = 0.32) did not differ between groups. Participant confidence levels were higher in the novel technique group (p < 0.001). Magnetic needle navigation can reduce the number of needle redirections, shorten the time to successful cannulation, and increase confidence levels by novice learners for successful US-guided central venous access.

THE EARLY HISTORY OF MAGNETIC EXPLORATION IN NORTH AMERICA

ABSTRACT Over the past nearly two centuries the magnetic method has been one of the most useful and broadly applied techniques for geologic mapping. Prior to the development of aeromagnetic surveying following World War II magnetic exploration was restricted to ground surveying using primarily mechanical instruments which measured the angular relationships or oscillation of a magnetic needle. This instrumentation was developed initially in western Europe for mapping the geomagnetic field and then iron ore deposits beginning in the seventeenth century. As the instrumentation evolved, sensitivity increased allowing the magnetic method to map additional geologic units of decreasing magnetization. The method was brought to North America where abnormal declination of the magnetic field as measured with the compass was used to map intensely magnetic ironrich rocks in the New Jersey highlands and adjacent New York in the early 1700s. Counterweighted magnetic needles (dip needles) oscillating vertically in the magnetic meridian were developed during the late eighteenth century in Scandinavia for measuring magnetic intensity anomalies that are more readily interpreted than the angular measurements of the compass. These instruments were brought to the eastern United States and were put into use in the mid-1800s in the search for banded iron formations and magnetite-bearing metamorphic and igneous rocks of interest to ore exploration. Similar instrumentation was developed in the British Isles in the first half of the 1800s for national surveys and later for geological exploration. The dip needle and a modification of the sun compass for geologic purposes, the dial compass, were commonly used together for mapping magnetic anomalies of iron ore deposits especially in the Lake Superior region from the U.S. Civil War to World War II. To increase the sensitivity and precision of the measurements numerous additional instruments were developed based on the principle of the dip needle. Particularly important among these were the Schmidt-type magnetometer and Hotchkiss superdip which were widely used in North America after the early 1920s and well into the 1950s. These and similar instruments opened the application of the magnetic method to a broad range of geologic problems important to mineral and petroleum exploration and engineering studies. Interpretation of the mapped magnetic anomalies was advanced with newly developed theoretical representations and model studies of the magnetic intensity of idealized geologic sources that were compared to observed magnetic anomalies.

Percutaneous Magnetic Resonance Imaging-Guided Coaxial Cutting Needle Biopsy of Pancreatic Lesions: Diagnostic Accuracy and Safety.

To appraise the diagnostic performance of magnetic resonance imaging-guided percutaneous coaxial cutting needle biopsy of pancreatic lesions using a 0.4-T open magnetic resonance imaging scanner with optical tracking navigation. This retrospective study included 158 patients who underwent magnetic resonance imaging-guided pancreatic lesion biopsy procedures from May 2019 to December 2020. Two to four specimens were collected from each patient. Pathological diagnosis and clinical follow-ups were conducted to establish the final diagnosis. The procedures were evaluated for sensitivity, specificity, positive and negative predictive values, diagnostic accuracy, and complications. The Cardiovascular and Interventional Radiological Society of Europe guidelines were used to classify complications. Biopsy pathology revealed 139 pancreatic tumor malignancies and 19 benign pancreatic lesions. Finally, 151 patients were diagnosed with pancreatic malignancy and 7 with benign disease confirmed by surgery, re-biopsy, and clinical follow-up. The sensitivity, specificity, positive and negative predictive value, and accuracy for diagnosis of pancreatic diseases were 92.1%, 100%, 100%, 36.8%, and 92.4%, respectively. The biopsy accuracy was significantly related to the size (≤ 2cm, 76.2%; 2-4cm, 94.0%; > 4cm, 96.2%, P = .02) and not the lesion's location (head of pancreas, 90.7%; neck of pancreas, 88.9%; body of pancreas, 94.3%; tail of pancreas, 96.7%, P = .73). Minor complications included two patients experiencing mild abdominal pain and two with a minor occurrence of hemorrhage. Percutaneous magnetic resonance imaging-guided pancreatic lesion biopsy combined with optical navigation has high diagnostic accuracy and is safe for clinical practice. Level of Evidence Level 4, Case-series.

Acupuncture and Static Multipolar Magnets: An Emerging Attraction?

Magnetism has been known for >4,000 years. Recently static multipolar magnets have demonstrated analgesic clinical usefulness. Local application of magnets may be beneficial in reducing musculoskeletal pain, particularly when other modalities have failed. A recent series of clinical cases demonstrates how multipolar magnets may be incorporated as an effective adjunctive treatment in an acupuncture clinic. PubMed database was searched using the key words: magnets, medical magnets, magnets and pain management, therapeutic magnets, multipolar magnets, and history of magnet therapy. In addition, clinical cases were submitted by 4 different medical acupuncturists as examples of how the use of multipolar magnets is incorporated into an acupuncture clinic. Over the past 20 years, 143 articles fulfilled the search criteria and unfortunately demonstrated considerable variability in research methodology. Magnetic tapes, needles, and beads of various magnetic strengths constituted the stimulating apparatus with durations ranging from minutes to years. This article highlights 10 cases, 9 of which reflected situations in which the use of 1 or more multipolar magnets provided an enhanced analgesic effect, often when traditional acupuncture had either failed to produce a satisfactory response or when the application of acupuncture needles needed to be limited. Despite the variability of the literature review, it appears that magnetism is related to pain reduction, and when properly employed, it can be an effective and safe modality as demonstrated by a recent series of cases submitted from the practices of 4 different medical acupuncturists. A clinical trial incorporating the latest technology of multipolar magnets with steep field gradients should be initiated for the more formal investigation of magnet-induced analgesia.

Magnetic Signatures and Magnetization Mechanisms for Grinding Burns Detection and Evaluation.

Grinding thermal damages, commonly called grinding burns occur when the grinding energy generates too much heat. Grinding burns modify the local hardness and can be a source of internal stress. Grinding burns will shorten the fatigue life of steel components and lead to severe failures. A typical way to detect grinding burns is the so-called nital etching method. This chemical technique is efficient but polluting. Methods based on the magnetization mechanisms are the alternative studied in this work. For this, two sets of structural steel specimens (18NiCr5-4 and X38Cr-Mo16-Tr) were metallurgically treated to induce increasing grinding burn levels. Hardness and surface stress pre-characterizations provided the study with mechanical data. Then, multiple magnetic responses (magnetic incremental permeability, magnetic Barkhausen noise, magnetic needle probe, etc.) were measured to establish the correlations between the magnetization mechanisms, the mechanical properties, and the grinding burn level. Owing to the experimental conditions and ratios between standard deviation and average values, mechanisms linked to the domain wall motions appear to be the most reliable. Coercivity obtained from the Barkhausen noise, or magnetic incremental permeability measurements, was revealed as the most correlated indicator (especially when the very strongly burned specimens were removed from the tested specimens list). Grinding burns, surface stress, and hardness were found to be weakly correlated. Thus, microstructural properties (dislocations, etc.) are suspected to be preponderant in the correlation with the magnetization mechanisms.

Phantom-based assessment of motion and needle targeting accuracy of robotic devices for magnetic resonance imaging-guided needle biopsy.

The current study proposes simple methods for assessing the performance of robotic devices intended for Magnetic Resonance Imaging (MRI)-guided needle biopsy. In-house made agar-based breast phantoms containing biopsy targets served as the main tool in the evaluation process of an MRI compatible positioning device comprising a needle navigator. The motion accuracy of mechanical stages was assessed by calliper measurements. Laboratory evaluation of needle targeting included a repeatability phantom test and a laser-based method. The accuracy and repeatability of needle targeting was also assessed by MRI. The maximum error of linear motion for steps up to 10mm was 0.1mm. Needle navigation relative to the phantom and alignment with the various biopsy targets were performed successfully in both the laboratory and MRI settings. The proposed biopsy phantoms offered tissue-like signal in MRI and good haptic feedback during needle insertion. The proposed methods could be valuable in the process of validating the accuracy of MRI-guided biopsy robotic devices in both laboratory and real environments.

A Case of Glossopharyngeal Schwannoma Protruding to the Larynx: A Case Report

Schwannoma is benign tumor that can occur in any part of the nerve that contains a Schwann cell. It is rare in the head and neck region and is characterized by common postoperative neurologic symptoms. We experienced a cervical schwannoma in a 22-year-old young man. Except for a foreign body sensation in the neck and a mass in the anterior region, there were no other complaints. A retropharyngeal schwannoma was most suspected considering neck computed tomography, magnetic resonance imaging, laryngoscopy and fine needle aspiration. Surgical treatment was performed, and the origin of the schwannoma was diagnosed as the tonsillar branch of the glossopharyngeal nerve. Histopathological examination confirmed the presence of a schwannoma with typical characteristics. After surgery, the patient recovered without any side effects. We report this case with a review of the literature.

Визначення еталонних напрямків на сертифікованому поліґоні з використанням GNSS вимірювань

This work examines the results of experimental GNSS measurements in 2022 performed at the points of the scientific geodetic range (NSG). The purpose of the research is to perform simultaneous GNSS measurements at four points of the reference linear base (ELB) section and to process experimental GNSS observations at points of the metrological calibrated geodetic network to determine reference azimuths and directional angles. Method. Experimental measurements were carried out using two frequency GNSS receivers with every second registration of signals and binding to the nearest permanent stations that are part of the International GNSS service: GEOTERRACE. The paper considers the application of the method of calculating azimuths using geodetic coordinates of points and parameters of reference ellipsoids. The results. Data processing of synchronous observations of points (ELB) and permanent stations was performed in the Leica Geo Office software complex. The value of the marginal error of determining the coordinates of the investigated points does not exceed 5 mm. The results of the calculations of the investigated azimuths for different coordinate systems and the accuracy of their determination are given. The parameters of the Krasovsky, WGS-84 and ITRF 2000 ellipsoid references were used for the calculations. The calculated values of the direction angles in the USK 2000 coordinate system for the six-degree zone. Scientific novelty. The possibility of using GNSS measurements for creating reference directions, determining their azimuths and directional angles is shown. An accuracy assessment was carried out based on the results of the measurements. The calculated accuracy of determining the azimuths of the directions depends on the accuracy of determining their coordinates and the distance between observation points. The obtained formula for calculating the accuracy of direction determination in angular units. Practical significance. The stability of the points calibrated by the metrological service of the ELB NHP section over time has been confirmed, which gives grounds for using the investigated directions as standards for calibration of navigation equipment. Calculated azimuths and direction angles of the selected directions for different coordinate reference systems. The calculated value of the convergence of the meridians for the six-degree zone of USK 2000 point P-1. The obtained values of true azimuths can be used to study the inclination of the magnetic needle.

Study on the effect of magnetic needle grinding on the surface integrity and service performance of medical Mg-0.8Ca alloy

Medical magnesium alloys as biodegradable medical materials are regarded as the third generation of biomedical materials with good biocompatibility and degradability. Still, their application is greatly limited due to their excessive corrosion rate and low mechanical strength. This paper investigates the effect of surface integrity, wettability, and corrosion resistance of Mg-0.8Ca alloy milled surfaces and further magnetic needle magnetic grinding treated surfaces. The test results show that the surface roughness increases after grinding due to the change in surface morphology and work hardening. Still, microhardness, residual compressive stress, wettability, and corrosion resistance are all improved, and the surface is more conducive to cell adhesion and growth. Comparative tests have shown that magnetic pin grinding can effectively enhance magnesium alloy’s application strength and serviceability.

Ionic Liquid-Based Magnetic Needle Headspace Single-Drop Microextraction Combined with HPLC/UV for the Determination of Chlorophenols in Wastewater.

A magnetic needle headspace single-drop microextraction (MN-HS-SDME) method coupled to HPLC/UV has been developed. Trihexyl(tetradecyl)phosphonium chloride was employed as an ionic liquid (IL) solvent for the headspace extraction of some chlorophenol (CP) compounds from wastewater samples. Despite of the nonmagnetic character of the IL, a significant improvement in the extraction efficiency was obtained by the magnetization of the single-drop microextraction needle using a pair of permanent disk magnets. A simplex method for the fast optimization of the experimental conditions (e.g., stirring speed, ionic strength, pH, extraction time and temperature) was used. The coefficients of determination (R2) varied between 0.9932 and 0.9989, the limits of detection were from 0.004 to 0.007μgmL-1 and the relative recoveries were in the range of 88-120% for the studied analytes. The developed MN-HS-SDME HPLC/UV method was successfully applied to the determination of CPs in industrial wastewater.

Magnetic Field Analysis and Optimization of the Gauge of Hybrid Maglev Needles

Compared with the traditional needle driving method, hybrid maglev needle driving is a new weft knitting machine technology, which alleviates the problems of noise, heat, and needle breakage. However, in the structure of needle arrays, magnetic disturbance between permanent magnet knitting needles leads to unstable needle control. Therefore, this paper attempts to solve this problem through a performance analysis of hybrid maglev needle driving. Based on the structure, the magnetic force distribution model of permanent magnet knitting needles is established. Aiming at the magnetic interference between magnetic arrays, a magnetic shielding material, silicon steel with a high permeability, is proposed to optimize the driving structure of a magnetic levitation needle array. Through simulation and experimental analysis, the influence of different silicon steel thicknesses on magnetic field shielding is analyzed. It is concluded that the optimal value of a silicon steel sheet is 1 mm and that the optimal gauge of hybrid maglev knitting needles is 8 mm. Finally, compared with the theoretical and simulation analysis, the experimental results have indicated that the proposed optimized structure of the gauge of hybrid maglev knitting needles is correct and effective.

Time-Scale Separation Analysis for Surgical Needle Control in Electromagnetic Robotic Systems

In this work, we use the theory of time-scale separation to analyze motion of magnetic needles powered by electromagnetic coils for surgical tasks. In developing model-based controllers for such systems, it is often assumed that the magnetic needle orientation is aligned with the magnetic field direction. This assumption has enabled use of open-loop control techniques for orientation control of the magnetic agent. We provide a framework to show how this assumption might be highly inaccurate for certain system parameters. We show numerical simulations to depict this and validate results with experiments on a real magnetic control system. The results of this work can help ascertain whether the orientation alignment assumption is valid for a given set of parameters, paving the way to enable safe and accurate implementation of surgical tasks using magnetic needles in clinical settings.