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Journal of Laparoendoscopic & Advanced... May 2022The use of magnetic devices in digestive surgery has been a matter of debate in recent years. The aim of this review was to describe the physical bases, indications,... (Review)
Review
The use of magnetic devices in digestive surgery has been a matter of debate in recent years. The aim of this review was to describe the physical bases, indications, and results of the use of magnets in digestive surgery. A review of the literature was performed using Scopus, PubMed, ScienceDirect, and SciELO databases considering as inclusion criteria all articles published since 2007 to date, describing the physical basis of magnetic assisted surgery and those that describe the surgical procedure, including case reports, as well as, articles on humans and experimental animals. Sixty-four studies were included, 15 detailing aspects on the physical basis and 49 about indications and results. Magnets are currently used to perform fixed traction, mobilizing structures, and anastomosis in humans and experimental animals. The use of magnets in digestive surgery has shown good results, and no complications arising from their use have been reported. However, more prospective and randomized studies that compare magnetic surgery and conventional techniques are needed.
Topics: Anastomosis, Surgical; Animals; Digestive System Surgical Procedures; Humans; Magnetics; Magnets; Prospective Studies
PubMed: 34492199
DOI: 10.1089/lap.2021.0314 -
Mass Spectrometry Reviews Mar 2022The world of Fourier-transform ion cyclotron resonance (FT-ICR) mass spectrometry has witnessed, especially in the last 30 years significant advances in many fields of... (Review)
Review
The world of Fourier-transform ion cyclotron resonance (FT-ICR) mass spectrometry has witnessed, especially in the last 30 years significant advances in many fields of science, such as electronics, magnets, new ICR cell designs, developed ICR event sequences, modern external ionization sources, and linear ion beam guides, as well as modern vacuum technology. In this review, a brief account is given focusing especially on the studies performed in Wanczek's group and ICR research laboratory at the University of Bremen. An FT-ICR mass spectrometer has been developed with a high magnetic field superconducting magnet, operating at 4.7 T. At this magnetic field, a trapping time of 13.5 h was obtained with 30% efficiency. For the tetrachloromethane molecular ion, m/z 166, a mass-resolving power m/Δm = 1.5 × 10 was measured at a pressure of 2 × 10 Torr. The transition from magnet sweep to frequency sweep and the application of Fourier-transform has greatly enhanced the ICR technology. External ion sources were invented and differential pumping schemes were developed for enabling ultrahigh vacuum condition for ICR detection, while guiding ions at relatively higher pressures, during their flight to the ICR cell. With the external ion source, a time-of-flight ICR tandem instrument is built. A method to measure the ion flight time and to trap the ions in the ICR cell is described. Many ICR cell characteristics such as z-axis ion ejection and coupling of radial and axial ion motions in a superposed homogeneous magnetic and inhomogeneous trapping electric field were extensively studied. Gas-phase ion-molecule reactions of several reactive inorganic compounds with a focus on phosphorous and sulfur as well as silicon chemistry were also studied in great detail. The gas-phase ion chemistry of several trifluoromethyl-reagents such as trifluoromethyltrimethylsilane and tris(trifluoromethyl)phosphine were also investigated in ICR. Dual polarities multisegmented ICR cells were invented and deeply characterized. Sophisticated ICR pulse event programs were developed to enable long-range ion-ion interactions between simultaneously trapped positive and negative ions.
Topics: Fourier Analysis; Ions; Magnets; Mass Spectrometry; Superconductivity
PubMed: 33521990
DOI: 10.1002/mas.21682 -
IEEE Transactions on Biomedical... Apr 2022A new concept of human-machine interface to control hand prostheses based on displacements of multiple magnets implanted in the limb residual muscles, the myokinetic...
A new concept of human-machine interface to control hand prostheses based on displacements of multiple magnets implanted in the limb residual muscles, the myokinetic control interface, has been recently proposed. In previous works, magnets localization has been achieved following an optimization procedure to find an approximate solution to an analytical model. To simplify and speed up the localization problem, here we employ machine learning models, namely linear and radial basis functions artificial neural networks, which can translate measured magnetic information to desired commands for active prosthetic devices. They were developed offline and then implemented on field-programmable gate arrays using customized floating-point operators. We optimized computational precision, execution time, hardware, and energy consumption, as they are essential features in the context of wearable devices. When used to track a single magnet in a mockup of the human forearm, the proposed data-driven strategy achieved a tracking accuracy of 720 μm 95% of the time and latency of 12.07 μs. The proposed system architecture is expected to be more power-efficient compared to previous solutions. The outcomes of this work encourage further research on improving the devised methods to deal with multiple magnets simultaneously.
Topics: Hand; Humans; Magnetic Phenomena; Magnetics; Magnets; Neural Networks, Computer
PubMed: 35316192
DOI: 10.1109/TBCAS.2022.3161133 -
The Journal of Emergency Medicine Jun 2020Injuries from multiple magnet ingestions in the pediatric population have been increasing in both incidence and morbidity. This trend will likely continue after a 2017... (Review)
Review
BACKGROUND
Injuries from multiple magnet ingestions in the pediatric population have been increasing in both incidence and morbidity. This trend will likely continue after a 2017 court ruling that overturned a ban on the sale of magnet sets marketed as "adult desk toys." Depending on the arrangement of the ingested magnets in the gastrointestinal tract, the consequences can range from benign to life threatening.
OBJECTIVE
This review of cases aims to help clinicians recognize this pathology and help them appreciate the unique management of this type of foreign body ingestion.
DISCUSSION
Several cases are presented that individually illustrate an arm of the most comprehensive management algorithm, proposed by the North American Society for Pediatric Gastroenterology, Hepatology, and Nutrition. The management is largely driven by the clinical appearance of the child as well as information obtained through abdominal radiographs. Imaging variables that factor into management include the location of the magnets, the number of magnets, and the progression of magnets on serial radiographs.
CONCLUSION
This article uses cases and illustrative medical imaging to describe the most common scenarios and their management. This is especially relevant considering recent U.S. court rulings that overturned the U.S. Consumer Product Safety Commission's ban on the sale of toys containing multiple miniature magnets.
Topics: Child; Eating; Foreign Bodies; Gastrointestinal Tract; Humans; Magnets; Play and Playthings; Retrospective Studies
PubMed: 32317194
DOI: 10.1016/j.jemermed.2020.03.022 -
Cells Oct 2021The idea of remote magnetic guiding is developed from the underlying physics of a concept that allows for bijective force generation over the inner volume of magnet... (Review)
Review
The idea of remote magnetic guiding is developed from the underlying physics of a concept that allows for bijective force generation over the inner volume of magnet systems. This concept can equally be implemented by electro- or permanent magnets. Here, permanent magnets are in the focus because they offer many advantages. The equations of magnetic fields and forces as well as velocities are derived in detail and physical limits are discussed. The special hydrodynamics of nanoparticle dispersions under these circumstances is reviewed and related to technical constraints. The possibility of 3D guiding and magnetic imaging techniques are discussed. Finally, the first results in guiding macroscopic objects, superparamagnetic nanoparticles, and cells with incorporated nanoparticles are presented. The constructed magnet systems allow for orientation, movement, and acceleration of magnetic objects and, in principle, can be scaled up to human size.
Topics: Animals; Cells; Humans; Imaging, Three-Dimensional; Magnetic Fields; Magnetic Phenomena; Magnets; Nanoparticles
PubMed: 34685688
DOI: 10.3390/cells10102708 -
Chemistry (Weinheim An Der Bergstrasse,... Jan 2023Two pairs of chiral end-on azido-bridged dinuclear hexaazamacrocycles, [Dy (L ) (N ) Cl ](BPh ) (1R/1S) and [Dy (L ) (N ) ]Cl (2R/2S) (L is hexaazamacrocyclic neutral...
Two pairs of chiral end-on azido-bridged dinuclear hexaazamacrocycles, [Dy (L ) (N ) Cl ](BPh ) (1R/1S) and [Dy (L ) (N ) ]Cl (2R/2S) (L is hexaazamacrocyclic neutral Schiff base ligand derived from 2,6-diformylpyridine and (1R, 2R)/(1S, 2S)-diaminocyclohexane), were constructed by adjusting the molar ratio of sodium azide to Dy(III) macrocycle precursor. Structural analyses reveal that all Dy(III) centers in complexes 1R/1S and 2R/2S are nine-coordinate with hula-loop coordination geometry, and the differences between 1R/1S and 2R/2S are the terminal coordination anion and counter anion. Magnetic studies indicate that complex 2S displays typical SMM behaviors under a zero dc field, whereas 1S just shows slow relaxation of magnetization resulting from a relatively weak axial crystal field. Significantly, complex 2R/2S represents the first homochiral all-nitrogen-coordinated lanthanide single-molecule magnet.
Topics: Magnets; Dysprosium; Lanthanoid Series Elements; Nitrogen
PubMed: 36326186
DOI: 10.1002/chem.202202896 -
Revista de Gastroenterologia de Mexico... 2022Endoscopic submucosal dissection (ESD) is a well-established treatment for superficial gastrointestinal tumors and enables en bloc resection. Adequate tissue tension is...
INTRODUCTION AND AIMS
Endoscopic submucosal dissection (ESD) is a well-established treatment for superficial gastrointestinal tumors and enables en bloc resection. Adequate tissue tension is important for safe and effective dissection. Simplified magnetic anchor-guided ESD (MAG-ESD) with a neodymium magnet has potential benefits, compared with other current traction methods. We evaluated the feasibility of simplified MAG-ESD in an ex vivo porcine model.
MATERIALS AND METHODS
An experimental study was conducted, utilizing the standard ESD technique. An external magnet and an internal magnet, both neodymium magnets, were used for the magnetic anchoring. The internal magnet was attached to an arm of a hemoclip with a 2-0 silk suture. After the incision, the clip with the internal magnet was placed at the edge of the lesion. The external magnet was maneuvered around the surface to apply adequate tension.
RESULTS
A total of 15 en bloc ESDs (5 with no magnetic anchoring and 10 with magnetic anchoring) were carried out. Traction and dissection were feasible in all cases and the procedures were completed in fewer than 90min. Lesion size ranged from 15 to 50mm (mean 30mm). Two cases in the group with magnetic anchoring presented with punctate perforation (13.3%).
CONCLUSIONS
Our study demonstrated the feasibility of simplified MAG-ESD and en bloc resection in an ex vivo porcine model.
Topics: Animals; Dissection; Endoscopic Mucosal Resection; Humans; Magnetic Phenomena; Magnets; Neodymium; Swine
PubMed: 35090672
DOI: 10.1016/j.rgmxen.2021.03.002 -
Digestive and Liver Disease : Official... Jun 2024To assess the clinical complications reported after the ingestion of magnetic foreign bodies (FBs) in pediatric age, along with their incidence among all FB ingestions...
OBJECTIVES
To assess the clinical complications reported after the ingestion of magnetic foreign bodies (FBs) in pediatric age, along with their incidence among all FB ingestions and clinical presentation.
STUDY DESIGN
We've consecutively recruited all children aged 0-14 years who were admitted for single or multiple magnet ingestion from May 2015 to December 2022. Patient demographics, admission sources and discharge status were accurately recorded, along with their clinical management and outcomes.
RESULTS
Sixty-one children were enrolled, of whom 49/61 (80.3%) had ingested a single magnet and 12/61 (19.7%) multiple magnets. Only 1/49 children with single magnet required endoscopic removal due to esophageal retention. Among children having ingested multiple magnets, 5/12 (41.7%) undergo endoscopic removal since magnets were amenable to endoscopic retrieval whereas in 7/12 (58.3%) magnets could not be promptly removed. Among these, 4/12 (33.3%) later developed intestinal ischemia/necrosis or perforation and required FB surgical intervention whereas 3/12 (25%) uneventfully evacuated magnets.
CONCLUSIONS
Our data confirm that multiple magnet ingestion, unlike single magnet ingestion, pose a serious health hazard. Parents and caregivers should remove them from the reach of children. Medical providers should maintain a high index of suspicion of their ingestion since prompt evaluation and likely removal may be lifesaving and intestine saving.
Topics: Humans; Foreign Bodies; Child; Child, Preschool; Male; Female; Infant; Adolescent; Magnets; Eating; Infant, Newborn
PubMed: 37985250
DOI: 10.1016/j.dld.2023.11.009 -
Magma (New York, N.Y.) Apr 2023The Iseult MRI is an actively shielded whole-body magnet providing a homogeneous and stable magnetic field of 11.7 T. After nearly 20 years of research and development,... (Review)
Review
OBJECTIVES
The Iseult MRI is an actively shielded whole-body magnet providing a homogeneous and stable magnetic field of 11.7 T. After nearly 20 years of research and development, the magnet successfully reached its target field strength for the first time in 2019. This article reviews its commissioning status, the gradient-magnet interaction test results and first imaging experience.
MATERIALS AND METHODS
Vibration, acoustics, power deposition in the He bath, and field monitoring measurements were carried out. Magnet safety system was tested against outer magnetic perturbations, and calibrated to define a safe operation of the gradient coil. First measurements using parallel transmission were also performed on an ex-vivo brain to mitigate the RF field inhomogeneity effect.
RESULTS
Acoustics measurements show promising results with sound pressure levels slightly above the enforced limits only at certain frequency intervals. Vibrations of the gradient coil revealed a linear trend with the B field only in the worst case. Field monitoring revealed some resonances at some frequencies that are still under investigation.
DISCUSSION
Gradient-magnet interaction tests at up to 11.7 T are concluded. The scanner is now kept permanently at field and the final calibrations are on-going to pave the road towards the first acquisitions on volunteers.
Topics: Humans; Magnets; Magnetic Resonance Imaging; Magnetic Fields; Magnetics; Whole Body Imaging
PubMed: 36715884
DOI: 10.1007/s10334-023-01063-5 -
Soft Robotics Oct 2021Emerging worm-like soft robots with various soft materials and different actuation mechanism have been frequently discussed. It is very challenging for soft robots in...
Emerging worm-like soft robots with various soft materials and different actuation mechanism have been frequently discussed. It is very challenging for soft robots in realizing a fast and untethered crawling. In this article, a biomimetic magnet embedded worm-like robot (shorted as "MagWorm") in the size of centimeter level is designed and investigated. The actuation of the MagWorm is achieved by housing permanent magnetic patches in its soft body, which interact with an external moving drive-magnet system. A dynamic model is established, coupling the discrete elastic rod model with magnetic actuation. The driving mechanism is then numerically studied. Quantitative comparisons between the numerical solution and experiment results show reasonable agreement. It is shown that the MagWorm can deform part of its body into a "Ω" shape and generate biomimetic crawling locomotion. The crawling speed of the robot is studied experimentally with different sizes. Some potential applications are also proposed and demonstrated. The MagWorm represents compact and low-cost solutions that use permanent magnets for remote actuation of soft robot and can be continuously operated during long procedures.
Topics: Biomimetics; Equipment Design; Locomotion; Magnets; Robotics
PubMed: 32822273
DOI: 10.1089/soro.2019.0167