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Archives de Pediatrie : Organe Officiel... Apr 2019We report three pediatric cases of two, five, and 12 neodymium magnet spheres ingested simultaneously. In two cases, endoscopic extraction failed because of the...
We report three pediatric cases of two, five, and 12 neodymium magnet spheres ingested simultaneously. In two cases, endoscopic extraction failed because of the strength of the magnetic attraction and a gastrotomy was performed to remove all magnets. In the third case, the magnets were not accessible endoscopically and were removed by laparotomy. We wish to warn consumer groups and pediatricians about the danger of neodymium magnets.
Topics: Child; Child, Preschool; Eating; Endoscopy, Digestive System; Foreign Bodies; Humans; Magnets; Male; Neodymium
PubMed: 30827774
DOI: 10.1016/j.arcped.2019.02.001 -
Molecules (Basel, Switzerland) Jun 2022Magnetic composites and self-healing materials have been drawing much attention in their respective fields of application. Magnetic fillers enable changes in the... (Review)
Review
Magnetic composites and self-healing materials have been drawing much attention in their respective fields of application. Magnetic fillers enable changes in the material properties of objects, in the shapes and structures of objects, and ultimately in the motion and actuation of objects in response to the application of an external field. Self-healing materials possess the ability to repair incurred damage and consequently recover the functional properties during healing. The combination of these two unique features results in important advances in both fields. First, the self-healing ability enables the recovery of the magnetic properties of magnetic composites and structures to extend their service lifetimes in applications such as robotics and biomedicine. Second, magnetic (nano)particles offer many opportunities to improve the healing performance of the resulting self-healing magnetic composites. Magnetic fillers are used for the remote activation of thermal healing through inductive heating and for the closure of large damage by applying an alternating or constant external magnetic field, respectively. Furthermore, hard magnetic particles can be used to permanently magnetize self-healing composites to autonomously re-join severed parts. This paper reviews the synthesis, processing and manufacturing of magnetic self-healing composites for applications in health, robotic actuation, flexible electronics, and many more.
Topics: Magnetic Fields; Magnetics; Robotics
PubMed: 35744920
DOI: 10.3390/molecules27123796 -
Nano Letters Oct 2021Organic molecules and specifically bio-organic systems are attractive for applications due to their low cost, variability, environmental friendliness, and facile...
Organic molecules and specifically bio-organic systems are attractive for applications due to their low cost, variability, environmental friendliness, and facile manufacturing in a bottom-up fashion. However, due to their relatively low conductivity, their actual application is very limited. Chiral metallo-bio-organic crystals, on the other hand, have improved conduction and in addition interesting magnetic properties. We developed a spin transistor using these crystals and based on the chiral-induced spin selectivity effect. This device features a memristor type behavior, which depend on trapping both charges and spins. The spin properties are monitored by Hall signal and by an external magnetic field. The spin transistor exhibits nonlinear drain-source currents, with multilevel controlled states generated by the magnetization of the source. Varying the source magnetization enables a six-level readout for the two-terminal device. The simplicity of the device paves the way for its technological application in organic electronics and bioelectronics.
Topics: Electric Conductivity; Electronics; Magnetic Fields; Magnetics; Metals
PubMed: 34662128
DOI: 10.1021/acs.nanolett.1c01865 -
Sensors (Basel, Switzerland) Nov 2014
Topics: Forecasting; Magnetic Resonance Imaging; Magnetic Resonance Spectroscopy; Magnetics; Transducers
PubMed: 25407909
DOI: 10.3390/s141121722 -
Sensors (Basel, Switzerland) Sep 2020Biosensors based on magneto-impedance (MI) effect are powerful tools for biomedical applications as they are highly sensitive, stable, exhibit fast response, small in... (Review)
Review
Biosensors based on magneto-impedance (MI) effect are powerful tools for biomedical applications as they are highly sensitive, stable, exhibit fast response, small in size, and have low hysteresis and power consumption. However, the performance of these biosensors is influenced by a variety of factors, including the design, geometry, materials and fabrication procedures. Other less appreciated factors influencing the MI effect include measuring circuit implementation, the material used for construction, geometry of the thin film sensing element, and patterning shapes compatible with the interface microelectronic circuitry. The type magnetic (ferrofluid, Dynabeads, and nanoparticles) and size of the particles, the magnetic particle concentration, magnetic field strength and stray magnetic fields can also affect the sensor sensitivity. Based on these considerations it is proposed that ideal MI biosensor sensitivity could be achieved when the sensor is constructed in sandwich thick magnetic layers with large sensing area in a meander shape, measured with circuitry that provides the lowest possible external inductance at high frequencies, enclosed by a protective layer between magnetic particles and sensing element, and perpendicularly magnetized when detecting high-concentration of magnetic particles.
Topics: Biosensing Techniques; Electric Impedance; Magnetic Fields; Magnetics; Nanoparticles
PubMed: 32932740
DOI: 10.3390/s20185213 -
Journal of Medicine and Life Apr 2023Magnets have been widely used in dentistry as a means of retention in various prosthodontic applications. This review summarizes the historical background, types, and... (Review)
Review
Magnets have been widely used in dentistry as a means of retention in various prosthodontic applications. This review summarizes the historical background, types, and modes of action of magnets in dentistry, including their uses in conventional removable prostheses, sectional dentures, overdentures, maxillofacial prostheses, and implant-supported prostheses. A comprehensive electronic literature search was performed through multiple databases, including Medline via Pubmed, Wiley Online Library, Ebscohost, Science Direct, and Google Scholar. We used the following keywords: "magnets", "retention", "overdenture", and "maxillofacial prosthesis", with a focus on articles published between October 1953 and March 2016. We found 20 articles, and 16 were selected for inclusion in this review based on their relevance to the topic at hand. Recent advancements in magnetic technology have resulted in newer magnets that exhibit superior biological compatibility and corrosion resistance. These properties have made magnets an effective retentive aid intra- and extra-orally.
Topics: Humans; Magnets; Artificial Limbs; Electronics; PubMed
PubMed: 37305814
DOI: 10.25122/jml-2020-0012 -
Swiss Dental Journal Feb 2023
Topics: Humans; Magnets; Tooth Injuries
PubMed: 36723436
DOI: No ID Found -
Saudi Medical Journal Aug 2021To systematically review the occurrence of magnet or receiver/stimulator displacement following cochlear implant (CI) placement complication and evaluate the existing...
OBJECTIVES
To systematically review the occurrence of magnet or receiver/stimulator displacement following cochlear implant (CI) placement complication and evaluate the existing literature on this topic.
METHODS
A systematic literature search was conducted using PubMed, Scopus, Web of Science, Virtual Health Library (VHL), and Cochrane Library. Original studies reporting cases of magnet or receiver-stimulator migration occurring as a complication after CI placement were included. The quality of the included studies was evaluated using the National Institutes of Health Quality Assessment Tool for observational studies and CARE checklist for case studies.
RESULTS
A total of 36 studies, including 6469 patients, were included. Magnet migration was reported in 82 (1.3%) patients, while receiver/stimulator was reported in 4 (0.1%) cases. The cause of magnet migration was identified in 78 cases; MRI-induced movement was the most frequently reported cause (n=43, 55.1%), followed by head trauma (n=25, 32.1%). A total of 20 studies involving 35 patients with magnet migration performed skull radiography to diagnose magnet migration. Revision/exploratory surgery with surgical repositioning or replacement was the most frequent management procedure (n=46).
CONCLUSIONS
Further research on magnet pocket design and standard protocols for MRI in CI users is needed. Early diagnosis of magnet migration and instant referral to specialized CI centers is necessary for proper management and prevention of major complications. PROSPERO REG. NO. CRD: 42020204514.
Topics: Cochlear Implantation; Cochlear Implants; Humans; Magnetic Resonance Imaging; Magnets; Reoperation
PubMed: 34344804
DOI: 10.15537/smj.2021.42.8.20210294 -
BJS Open May 2022Magnets and button batteries (BBs) are dangerous ingested foreign bodies in children. The scale and consequences of this public health issue in the UK are unknown. This... (Observational Study)
Observational Study
BACKGROUND
Magnets and button batteries (BBs) are dangerous ingested foreign bodies in children. The scale and consequences of this public health issue in the UK are unknown. This study aims to report the current management strategies and outcomes associated with paediatric magnet and BB ingestion in the UK.
METHODS
This multicentre, retrospective observational study involved 13 UK tertiary paediatric surgery centres. Children aged under 17 years, admitted between 1 October 2019 and 30 September 2020, following magnet, or BB ingestion were included. Demographics, investigations, management, and complications were recorded.
RESULTS
In total, 263 patients were identified, comprising 146 (55.5 per cent) magnet, 112 (42.6 per cent) BB, and 5 (1.9 per cent) mixed magnet BB ingestions. Median (interquartile range) age was 4.8 (2.0-9.1) years and 47.5 per cent were female. In the magnet group, 38 (26.0 per cent) children swallowed single magnets, 3 of whom underwent endoscopic retrieval for oesophageal or gastric impaction. Of the 108 (74.0 per cent) children who swallowed multiple magnets, 51 (47.2 per cent) required endoscopic or surgical intervention, predominantly for failure of magnets to progress on serial imaging. Bowel perforations occurred in 10 children (9.3 per cent). Younger age and ingestion of greater numbers of multiple magnets were independently associated with surgery. BB ingestion caused morbidity in 14 children (12.5 per cent) and life-threatening injuries in two (1.8 per cent); the majority were caused by oesophageal BBs (64.3 per cent).
CONCLUSION
Multiple magnet and BB ingestions are associated with significant morbidity. Action must be taken at an international level to regulate the sale of magnets and BBs, and to raise awareness of the risks that these objects pose to children.
Topics: Child; Eating; Female; Hospitalization; Humans; Intestinal Perforation; Magnets; Male; Specialties, Surgical
PubMed: 35657136
DOI: 10.1093/bjsopen/zrac056 -
Biosensors & Bioelectronics Apr 2018In the past few years, magnetoelectronics has emerged as a promising new platform technology in various biosensors for detection, identification, localisation and... (Review)
Review
In the past few years, magnetoelectronics has emerged as a promising new platform technology in various biosensors for detection, identification, localisation and manipulation of a wide spectrum of biological, physical and chemical agents. The methods are based on the exposure of the magnetic field of a magnetically labelled biomolecule interacting with a complementary biomolecule bound to a magnetic field sensor. This Review presents various schemes of magnetic biosensor techniques from both simulation and modelling as well as analytical and numerical analysis points of view, and the performance variations under magnetic fields at steady and nonstationary states. This is followed by magnetic sensors modelling and simulations using advanced Multiphysics modelling software (e.g. Finite Element Method (FEM) etc.) and home-made developed tools. Furthermore, outlook and future directions of modelling and simulations of magnetic biosensors in different technologies and materials are critically discussed.
Topics: Biosensing Techniques; Finite Element Analysis; Magnetics; Models, Molecular; Software
PubMed: 29278815
DOI: 10.1016/j.bios.2017.12.023