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1.
Sci Rep ; 12(1): 6285, 2022 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-35428775

RESUMO

Recent technical advancements allow cardiac MRI (CMR) examinations in the presence of so-called MRI conditional active cardiac implants at 3.0 T. However, the artifact burden caused by susceptibility effects remain an obstacle. All measurements were obtained at a clinical 3.0 T scanner using an in-house designed cubic phantom and optimized sequences for artifact evaluation (3D gradient echo sequence, multi-slice 2D turbo spin echo sequence). Reference sequences according to the American Society for Testing and Materials (ASTM) were additionally applied. Four representative active cardiac devices and a generic setup were analyzed regarding volume and shape of the signal void. For analysis, a threshold operation was applied to the grey value profile of each data set. The presented approach allows the evaluation of the signal void and shape even for larger implants such as ICDs. The void shape is influenced by the orientation of the B0-field and by the chosen sequence type. The distribution of ferromagnetic material within the implants also matters. The void volume depends both on the device itself, and on the sequence type. Disturbances in the B0 and B1 fields exceed the visual signal void. This work presents a reproducible and highly defined approach to characterize both signal void artifacts at 3.0 T and their influencing factors.


Assuntos
Artefatos , Próteses e Implantes , Imageamento por Ressonância Magnética , Imãs , Imagens de Fantasmas
2.
J Neural Eng ; 19(2)2022 Apr 21.
Artigo em Inglês | MEDLINE | ID: mdl-35390778

RESUMO

Objective. Proprioception is the sense of one's position, orientation, and movement in space, and it is of fundamental importance for motor control. When proprioception is impaired or absent, motor execution becomes error-prone, leading to poorly coordinated movements. The kinaesthetic illusion, which creates perceptions of limb movement in humans through non-invasively applying vibrations to muscles or tendons, provides an avenue for studying and restoring the sense of joint movement (kinaesthesia). This technique, however, leaves ambiguity between proprioceptive percepts that arise from muscles versus those that arise from skin receptors. Here we propose the concept of a stimulation system to activate kinaesthesia through the untethered application of localized vibration through implanted magnets.Approach. In this proof-of-concept study, we use two simplified one-DoF systems to show the feasibility of eliciting muscle-sensory responses in an animal model across multiple frequencies, including those that activate the kinaesthetic illusion (70-115 Hz). Furthermore, we generalized the concept by developing a five-DoF prototype system capable of generating directional, frequency-selective vibrations with desired displacement profiles.Main results. In-vivotests with the one-DoF systems demonstrated the feasibility to elicit muscle sensory neural responses in the median nerve of an animal model. Instead,in-vitrotests with the five-DoF prototype demonstrated high accuracy in producing directional and frequency selective vibrations along different magnet axes.Significance. These results provide evidence for a new technique that interacts with the native neuro-muscular anatomy to study proprioception and eventually pave the way towards the development of advanced limb prostheses or assistive devices for the sensory impaired.


Assuntos
Ilusões , Imãs , Animais , Membro Anterior , Ilusões/fisiologia , Movimento/fisiologia , Músculos/inervação , Músculos/fisiologia , Propriocepção/fisiologia , Roedores , Vibração
3.
Bioelectromagnetics ; 43(4): 278-291, 2022 May.
Artigo em Inglês | MEDLINE | ID: mdl-35485707

RESUMO

With the wide application of magnetic resonance imaging in hospitals and permanent magnets in household items, people have increased exposure to various types of static magnetic fields (SMFs) with moderate and high intensities, which has caused a considerable amount of public concern. Studies have shown that some aspects of gametogenesis and early embryonic development can be significantly affected by SMFs, while others have shown no effects. This review summarizes the experimental results of moderate to high-intensity SMFs (1 mT-16.7 T) on the reproductive development of different model animals, and we find that the effects of SMFs are variable depending on experimental conditions. In general, the effects of inhomogeneous SMFs seem to be more significant compared to that of homogeneous SMFs, which is likely due to magnetic forces generated by the magnetic field gradient. Moreover, some electromagnetic fields may have induced bioeffects because of nonnegligible gradient and heat effect, which are much reduced in superconducting magnets. We hope this review can provide a starting point for more in-depth analysis of various SMFs on reproduction, which is indispensable for evaluating the safety and potential applications of SMFs on living organisms in the future. © 2022 Bioelectromagnetics Society.


Assuntos
Campos Eletromagnéticos , Campos Magnéticos , Animais , Humanos , Imageamento por Ressonância Magnética , Imãs , Reprodução
4.
Dalton Trans ; 51(17): 6918-6926, 2022 May 03.
Artigo em Inglês | MEDLINE | ID: mdl-35445682

RESUMO

A series of Zn-Ln heteronuclear SMMs constructed by using a hexadentate compartment Schiff base Zn-precursor and lanthanoid ions were structurally and magnetically characterized, in which the two [Zn-Ln] moieties are bridged by a series of hydroxamic acids, resulting in double-decker tetranuclear complexes with the molecular formulae [ZnL1Ln(C2H5O)(qua)]2(CF3SO3)2·2C2H5OH ((1) Ln = Dy; (7) Ln = Yb), [ZnL1Ln(CH3O)(bnz)]2(CF3SO3)2·2CH3OH ((2) Ln = Dy), [ZnL1Ln(CH3O)(aca)]2(CF3SO3)2·2CH3OH ((3) Ln = Dy; (8) Ln = Yb), [ZnL2Dy(CH3O)(bnz)]2(CF3SO3)2·2CH3OH (4), [ZnL2Dy(CH3O)(aca)]2(CF3SO3)2·2CH3OH (5), and [ZnL3Dy(CH3O)(bnz)]2(CF3SO3)2·2CH3OH (6) (HL1 = N,N'-bis(2-hydroxy-3-methoxybenzylidene)-1,2-phenylenediamine, HL2 = N,N'-bis(2-hydroxy-3-methoxybenzylidene)-propane-1,2-diamine, HL3 = N,N'-bis(3-methoxysalicylidene)-1,3-propanediamine, qua = 2-quinolinecarboxylic acid, bnz = benzhydroxamic acid and aca = acetohydroxamic acid). Strikingly, the slow magnetic relaxation can be tuned by modifying the steric hindrance and/or electronic effect on the backbone of the Shiff base and the terminal substituents of hydroxamic acid, as well the magneto-structural correlations are studied. Furthermore, Yb congeners 7 and 8 were synthesized to explore dual-functional materials with both magnetic and fluorescence properties, and they displayed both slow magnetic relaxation and near-infrared (NIR) properties; the low temperature NIR spectroscopic data were correlated with the corresponding slow magnetic relaxation mechanism involving thermally activated ground states to the excited state.


Assuntos
Luminescência , Bases de Schiff , Diaminas , Ácidos Hidroxâmicos , Imãs , Bases de Schiff/química , Zinco/química
5.
Small ; 18(16): e2107426, 2022 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-35274450

RESUMO

Nanometric core@shell wüstite@ferrite (Fe1- x O@Fe3 O4 ) has been extensively studied because of the emergence of exchange bias phenomena. Since their actual implementation in modern technologies is hampered by the low temperature at which bias is operating, the critical issue to be solved is to obtain exchange-coupled antiferromagnetic@ferrimagnetic nanoparticles (NPs) with ordering temperature close to 300 K by replacing the divalent iron with other transition-metal ions. Here, the effect of the combined substitution of Fe(II)  with Co(II)  and Ni(II)  on the crystal structure and magnetic properties is studied. To this aim, a series of 20 nm NPs with a wüstite-based core and a ferrite shell, with tailored composition, (Co0.3 Fe0.7 O@Co0.8 Fe2.2 O4  and Ni0.17 Co0.21 Fe0.62 O@Ni0.4 Co0.3 Fe2.3 O4 ) is synthetized through a thermal-decomposition method. An extensive morphological and crystallographic characterization of the obtained NPs shows how a higher stability against the oxidation process in ambient condition is attained when divalent cation doping of the iron oxide lattice with Co(II)  and Ni(II)  ions is performed. The dual-doping is revealed to be an efficient way for tuning the magnetic properties of the final system, obtaining Ni-Co doped iron oxide core@shell NPs with high coercivity (and therefore, high energy product), and increased antiferromagnetic ordering transition temperature, close to room temperature.


Assuntos
Imãs , Nanopartículas , Compostos Férricos , Compostos Ferrosos , Nanopartículas/química , Tamanho da Partícula , Temperatura
6.
Nano Lett ; 22(7): 3165-3172, 2022 Apr 13.
Artigo em Inglês | MEDLINE | ID: mdl-35271282

RESUMO

CrGeTe3 (CGT) is a semiconducting vdW ferromagnet shown to possess magnetism down to a two-layer thick sample. Although CGT is one of the leading candidates for spintronics devices, a comprehensive analysis of CGT thickness dependent magnetization is currently lacking. In this work, we employ scanning SQUID-on-tip (SOT) microscopy to resolve the magnetic properties of exfoliated CGT flakes at 4.2 K. Combining transport measurements of CGT/NbSe2 samples with SOT images, we present the magnetic texture and hysteretic magnetism of CGT, thereby matching the global behavior of CGT to the domain structure extracted from local SOT magnetic imaging. Using this method, we provide a thickness dependent magnetization state diagram of bare CGT films. No zero-field magnetic memory was found for films thicker than 10 nm, and hard ferromagnetism was found below that critical thickness. Using scanning SOT microscopy, we identify a unique edge magnetism, contrasting the results attained in the CGT interior.


Assuntos
Magnetismo , Imãs , Temperatura
7.
Radiologe ; 62(5): 385-393, 2022 May.
Artigo em Alemão | MEDLINE | ID: mdl-35258684

RESUMO

Over the years the development of field strength in magnetic resonance imaging (MRI) has continued to increase from the low-field systems in the early years (0.2-0.5 T) to 1.5 T to 3 T to 7 T and more. In the last 2 years, there has been a renewed interest in MRI at lower fields, mainly driven by the development of "dry" superconductive magnets. The following article demonstrates that this renewed interest for lower fields is not a déjà vu purely driven by economic needs. The field strength appears to be from yesterday, but the combination with the tremendous improvements and innovations of all relevant components-gradients, radiofrequency system and especially new algorithms including the use of artificial intelligence (AI)-allow the realization of diagnostically adequate MRI without compromise in patient throughput and efficiency. In addition to the lower field, there are also some inherent advantages, e.g., for MRI of the lung and of metallic implants and especially for interventional MRI. It has already been shown that many of the devices used for interventional procedures (catheters, biopsy needles) can be used at lower fields without costly modifications. In addition, low-field MRI also allows the robust use of highly efficient sampling methods like spiral MRI. It is therefore safe to predict that low-field MRI is not only a cost-efficient compromise, but has the potential to open up new fields of application.


Assuntos
Inteligência Artificial , Imageamento por Ressonância Magnética , Algoritmos , Humanos , Imageamento por Ressonância Magnética/métodos , Imãs , Próteses e Implantes
8.
J Nurs Manag ; 30(4): 1027-1041, 2022 May.
Artigo em Inglês | MEDLINE | ID: mdl-35293059

RESUMO

AIM: To identify the relationship between the characteristics of hospitals in recruiting and retaining nurses (magnet properties) and nurses' professional values. BACKGROUND: In Turkey, there are a limited number of hospitals with the characteristics to enable nurses to stay in their institutions. The magnet properties of these hospitals and the professional values of the nurses working in these hospitals are not known. METHODS: This descriptive cross-sectional research included 612 nurses working in six hospitals accredited by the Joint Commission International. Data were collected using the Nursing Professional Values Scale-Revised (NPVS-R) and the Essentials of Magnetism Scale (EOM II). RESULTS: The mean NPVS-R score was high 102.0 (26-130). However, the mean EOM II score was found to be low at 2.2 (1.0-3.4). As the magnet properties of the hospitals increased, the professional values of the nurses decreased. CONCLUSION: There was a negative correlation between the magnet properties of hospitals and the professional values of the nurses. IMPLICATIONS FOR NURSING MANAGEMENT: The findings of this study highlight the necessity of creating a working environment with high magnet characteristics, which also includes the professional values of nurses. Nurse managers should investigate the reasons behind the low magnet properties of hospitals, raise awareness, and plan interventions to increase magnet properties of hospitals. Creating a supportive working environment, promotion of the salaries and work environment and decreasing workload are some of the important intervention areas in attracting and keeping nurses in the institution.


Assuntos
Satisfação no Emprego , Recursos Humanos de Enfermagem no Hospital , Estudos Transversais , Hospitais , Humanos , Imãs
9.
Cells ; 11(6)2022 03 10.
Artigo em Inglês | MEDLINE | ID: mdl-35326401

RESUMO

The importance of magnetic micro- and nanoparticles for applications in biomedical technology is widely recognised. Many of these applications, including tissue engineering, cell sorting, biosensors, drug delivery, and lab-on-chip devices, require remote manipulation of magnetic objects. High-gradient magnetic fields generated by micromagnets in the range of 103-105 T/m are sufficient for magnetic forces to overcome other forces caused by viscosity, gravity, and thermal fluctuations. In this paper, various magnetic systems capable of generating magnetic fields with required spatial gradients are analysed. Starting from simple systems of individual magnets and methods of field computation, more advanced magnetic microarrays obtained by lithography patterning of permanent magnets are introduced. More flexible field configurations can be formed with the use of soft magnetic materials magnetised by an external field, which allows control over both temporal and spatial field distributions. As an example, soft magnetic microwires are considered. A very attractive method of field generation is utilising tuneable domain configurations. In this review, we discuss the force requirements and constraints for different areas of application, emphasising the current challenges and how to overcome them.


Assuntos
Magnetismo , Nanopartículas , Separação Celular , Campos Magnéticos , Imãs
12.
Environ Sci Technol ; 56(7): 4404-4412, 2022 Apr 05.
Artigo em Inglês | MEDLINE | ID: mdl-35286072

RESUMO

The spent neodymium-iron-boron (NdFeB) magnet is a highly valuable secondary resource of rare earth elements (REEs). Hydrometallurgical processes are widely used in recovering REEs from spent NdFeB magnets, but they will consume large amounts of organic chemicals, leading to severe environmental pollution. This work developed an alternative green route to selectively recover REEs from spent NdFeB permanent magnets using a purely inorganic zinc salt. The Hammett acidity measurement showed that concentrated ZnCl2 solutions could be regarded as a strong Brønsted acid. Concentrated ZnCl2 solutions achieved a high separation factor (>1 × 105) between neodymium and iron through simple dissolution of their corresponding oxide mixture. In the simulated recovery process of spent NdFeB magnets, the Nd2O3 product was successfully recovered with a purity close to 100% after selective leaching by ZnCl2 solution, sulfate double-salt precipitation, and oxalic acid precipitation. The separation performance of the ZnCl2 solution for Nd2O3 and Fe2O3 remained almost unchanged after four cycles. The energy consumption and chemical inputs of this process are about 1/10 and half of the traditional hydrometallurgy process separately. This work provides a promising approach for the green recovery of secondary REE resources.


Assuntos
Imãs , Metais Terras Raras , Neodímio , Ácido Oxálico , Reciclagem
13.
Artigo em Russo | MEDLINE | ID: mdl-35236066

RESUMO

One of the current health care problems is a menopausal syndrome (MS), a set of symptoms characterized by specific metabolic, neurological, autonomous, and psychosomatic changes. Many authors believe that one of the main methods of prevention and treatment of menopausal disorders is hormone replacement therapy, but there are many contraindications. Therefore, there is increasing interest in the development of non-medicinal therapy methods, in particular, physiotherapeutic treatment. OBJECTIVE: To study the effect of total cryotherapy alone and in combination with transcranial magnet therapy on the microcirculation state and psychological status in patients with MS. MATERIAL AND METHODS: The study included 62 female patients (mean age was 51±1.9 years). Thirty-five (56%) patients had mild menopausal syndrome and 27 (44%) moderate severity. All patients were divided into two clinically and functionally comparable groups by simple randomization: Group 1: 30 patients who received total cryotherapy (TCT); Group 2: 32 patients who received complex treatment including TCT and transcranial magnet therapy. The blood lipid spectrum was studied in all patients before and after the treatment course. The psychological examination was carried out using the well-being/activity/mood test (WAM). The microcirculation state was assessed by laser Doppler flowmetry (LDF). RESULTS: The majority of the patients had abnormalities in the lipid spectrum, decreased psychological adaptation, and worsened microcirculation indices (according to LDF data). After a treatment course, improvement in the lipid spectrum, LDF, and WAM test scores according to all scales was more pronounced in group 2 patients receiving complex therapy. CONCLUSION: The combined effect of total cryotherapy and transcranial magnet therapy had a more pronounced positive impact on the lipid spectrum, psychoemotional state, and microcirculatory processes in patients with menopausal syndrome compared with the total cryotherapy alone. It can be assumed that this complex will be effectively used in practical healthcare.


Assuntos
Imãs , Perimenopausa , Crioterapia , Feminino , Humanos , Fluxometria por Laser-Doppler , Microcirculação , Pessoa de Meia-Idade
14.
Artigo em Russo | MEDLINE | ID: mdl-35236061

RESUMO

Migraine is a primary form of headache characterized by throbbing unilateral attacks, increased sensitivity to light and sound, accompanied by nausea and/or vomiting, lasting from 4 hours to 3 days. Developing and implementing new methods of pain relief is an urgent task of modern medicine. One of the safest and most commonly recommended methods is transcranial magnet therapy (TMT). OBJECTIVE: To evaluate the effect of TMT on improving the effectiveness of comprehensive therapy in patients with migraine. MATERIAL AND METHODS: A blind, randomized, placebo-controlled clinical trial was conducted, including 50 patients with migraine divided into three groups (the main group received TMT; the comparison group received low-frequency magnet therapy with a magnetic pulse duration of 250 µs; the control group received treatment with placebo device). The objectives were to study the TMT effect on reduction of the frequency and intensity of headache attacks, the severity of associated symptoms, reduction of medications use, including analgesics, in patients with migraine, as well as to evaluate the statistical difference in the effectiveness of magnetic therapy with different magnetic pulse ratio on all of the above parameters in study patients. RESULTS: According to the study data, a positive effect of TMT on the patients' condition was observed. After treatment, 76.9% of the patients in the main group had a reduction of headache intensity compared to the control group (35%) and a 47.8% decrease in analgesics use. In the main group, a reduction of nausea (73.3% of patients), acousticophobia (77.8% of patients), and photophobia (81.8% of patients) was noted. The HADS scale showed a 44.3% reduction in anxiety and depression in the main group. CONCLUSION: The clinical efficacy of TMT in patients with migraine has been demonstrated. In clinical practice, it is reasonable to use TMT to improve the treatment effectiveness in patients with migraine.


Assuntos
Imãs , Transtornos de Enxaqueca , Analgésicos/uso terapêutico , Método Duplo-Cego , Humanos , Transtornos de Enxaqueca/complicações , Transtornos de Enxaqueca/diagnóstico , Transtornos de Enxaqueca/terapia , Resultado do Tratamento
15.
J Biomech Eng ; 144(8)2022 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-35147159

RESUMO

Changes in synovial fluid viscosity may be used to detect joint disease; however, methods to evaluate these changes at the point-of-care are currently rudimentary. Previously, we demonstrated that magnetic particle translation through static synovial fluid could serve as a surrogate marker of synovial fluid mechanics. In this work, we examine the magnetic deflection of a stream of particles flowing through a stream of synovial fluid and relate this deflection to changes in fluid mechanics. First, a flow device was designed, where a stream of magnetic particles flows along with synovial fluid. As the particle stream approaches and passes a fixed permanent magnet, the particle stream deflects. Conceptually, as the synovial fluid viscosity decreases, the deflection of the particle stream should increase due to a decreased drag force opposing the force magnetization. To assess this concept, particle deflection was first measured in Newtonian glycerol solutions of known varying viscosity under different flow conditions. Next, the device was used to test bovine synovial fluid viscosity, which had been progressively degraded using ultrasonication. A strong correlation was observed between the deflection of the magnetic particles and the viscosity of the glycerol solutions (R2 = 0.987) and the amount of ultrasonic degradation of synovial fluid (R2 = 0.7045). In the future, the principle of particle deflection may be used to design point-of-care quantification of synovial fluid mechanics, as the assessment does not require particles to be separated from the fluid for quantification and could be conducted under simple flow conditions.


Assuntos
Glicerol , Líquido Sinovial , Animais , Bovinos , Glicerol/metabolismo , Fenômenos Magnéticos , Imãs , Líquido Sinovial/metabolismo , Viscosidade
16.
Otol Neurotol ; 43(4): e421-e426, 2022 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-35195570

RESUMO

OBJECTIVE: To determine if temporoparietal scalp thickness assessed via preoperative imaging predicts retention events in patients who have cochlear implants with diametric magnets and various sound processor types. STUDY DESIGN: Retrospective chart and radiological review. SETTING: Tertiary referral center. PATIENTS: One hundred forty-three adult patients who have cochlear implants with diametric magnets. MAIN OUTCOME MEASURES: Skin flap thickness, retention events, body mass index (BMI), and magnet strength. RESULTS: Of 42 patients with the most recent generation off-the-ear sound processor (OTE2), 13 (31.0%) had retention events. Of patients with a temporoparietal scalp thickness less than 8 mm, all patients could ultimately retain the device, though one of 26 was noted to have tenuous retention. Of patients with 8 to 10 mm skin flaps, 3 of 6 (50%) could not retain the device, and with more than 10 mm skin flaps, 7 of 10 (70%) could not retain the device. In the more than 10 mm group, two additional patients could not either retain the device at initial activation or were noted to have tenuous retention. Of 124 patients with behind-the-ear (BTE) sound processors, only 2 (1.6%) could not retain the device at initial activation, and 3 (2.4%) exhibited tenuous retention after 3 months of device use. Results from the first generation off-the-ear sound processor (OTE1) are also reported. CONCLUSIONS: Temporoparietal scalp thickness measured by preoperative imaging is associated with processor retention for patients with the OTE2 sound processor and diametric magnets. All patients with less than 8 mm scalp thickness could retain the OTE2, while 50% of patients with 8 to 10 mm scalp thickness and 70% with more than 10 mm scalp thickness could not retain the device. Patients should be counseled regarding their sound processor choice and/or considered candidates for skin flap reduction or other intervention as indicated. Retention events with BTE processors are rare.


Assuntos
Implante Coclear , Implantes Cocleares , Percepção da Fala , Adulto , Implante Coclear/métodos , Implantes Cocleares/efeitos adversos , Humanos , Imãs/efeitos adversos , Estudos Retrospectivos , Couro Cabeludo/cirurgia
17.
Technol Health Care ; 30(S1): 315-328, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35124608

RESUMO

BACKGROUND: High installation and operating cost have limited applications for many circumstances. In practice, primary and shielding coils cannot insert into the magnet pole simultaneously owing to deficient workspace for the planar permanent MRI systemsOBJECTIVE: To minimize eddy currents induced in the resist-eddy current plates and pole piece when the gradient coil current switches on and off rapidly. METHODS: A theoretical framework that have minimum power dispassion and magnetic energy with eddy plate is proposed for a planar gradient coil. The mirror image of the magnetostatic model is substituted into the stream function for designing a minimum power dispassion planar gradient coil. A finite-difference is used to formulate the coil distribution that makes magnetic field similar to the required magnetic field for gradient coil design. RESULTS: A coil designed with actively shielded was simulated and compared with the designed gradient coils using mirror image theory and piece pole effect. According to the numerical evaluation of the x and z coils, the operating currents in the cases were reduced to 34.4% using magnetostatic mirror-image method to replay the active shielding. Moreover, there was a significant improvement on the shielding effect when added to resistive eddy current plate. CONCLUSIONS: Using the magnetostatic mirror image theory and mirror-image model, the current density function that could not only gives the minimum power dissipation and magnetic energy with the presence of the eddy plate and pole piece effect, but also provides excellent coil performance compared with active shielding solution.


Assuntos
Imageamento por Ressonância Magnética , Imãs , Desenho de Equipamento , Humanos , Imageamento por Ressonância Magnética/métodos , Magnetismo
18.
Pediatrics ; 149(3)2022 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-35112127

RESUMO

BACKGROUND AND OBJECTIVES: High-powered magnets were effectively removed from the US market by the Consumer Product Safety Commission (CPSC) in 2012 but returned in 2016 after federal court decisions. The United States Court of Appeals for the 10th Circuit cited imprecise data among other reasons as justification for overturning CPSC protections. Since then, incidence of high-powered magnet exposure has increased markedly, but outcome data are limited. In this study, we aim to describe the epidemiology and outcomes in children seeking medical care for high-powered magnets after reintroduction to market. METHODS: This is a multicenter, retrospective cohort study of patients aged 0 to 21 years with a confirmed high-powered magnet exposure (ie, ingestion or insertion) at 25 children's hospitals in the United States between 2017 and 2019. RESULTS: Of 596 patients with high-powered magnet exposures identified, 362 (60.7%) were male and 566 (95%) were <14 years of age. Nearly all sought care for magnet ingestion (n = 574, 96.3%), whereas 17 patients (2.9%) presented for management of nasal or aural magnet foreign bodies, 4 (0.7%) for magnets in their genitourinary tract, and 1 patient (0.2%) had magnets in their respiratory tract. A total of 57 children (9.6%) had a life-threatening morbidity; 276 (46.3%) required an endoscopy, surgery, or both; and 332 (55.7%) required hospitalization. There was no reported mortality. CONCLUSIONS: Despite being intended for use by those >14 years of age, high-powered magnets frequently cause morbidity and lead to high need for invasive intervention and hospitalization in children of all ages.


Assuntos
Corpos Estranhos , Imãs , Adolescente , Criança , Ingestão de Alimentos , Endoscopia Gastrointestinal , Feminino , Corpos Estranhos/epidemiologia , Corpos Estranhos/cirurgia , Hospitais Pediátricos , Humanos , Imãs/efeitos adversos , Masculino , Estudos Retrospectivos , Estados Unidos/epidemiologia
19.
J Vis Exp ; (180)2022 02 09.
Artigo em Inglês | MEDLINE | ID: mdl-35225277

RESUMO

Mechanobiology describes how the physical forces and mechanical properties of biological material contribute to physiology and disease. Typically, these approaches are limited single-molecule methods, which restricts their availability. To address this need, a microplate assay was developed that enables mechanical manipulation while performing standard biochemical assays. This is achieved using magnets incorporated into a microplate lid to create multiple magnetic tweezers. In this format, force is exerted across biomolecules connected to paramagnetic beads, equivalent to a typical magnetic tweezer. The study demonstrates the application of this tool with FRET-based assays to monitor protein conformations. However, this approach is widely applicable to different biological systems ranging from measuring enzymatic activity through to the activation of signaling pathways in live cells.


Assuntos
Magnetismo , Imãs , Biofísica , Fenômenos Magnéticos , Nanotecnologia/métodos , Pinças Ópticas
20.
Artigo em Inglês | MEDLINE | ID: mdl-35139473

RESUMO

N-glycosylation is one of the major post-translational modifications, with significant effects on the mechanism of action, the efficacy, and the safety of antibody drugs or glycoproteins. With the growing application of therapeutic antibodies, routinely monitoring N-glycosylation becomes increasingly important during cell culture process development and quality control. However, the current pretreatment methods for N-glycan analysis are time- and labor-consuming. The purification procedure of enzymatically released glycans could also partly affect the accuracy of results due to its complexity. In this study, a rapid ultra-high performance liquid chromatography method based on magnetic bead extraction and 2-AB fluorescent labeling was developed and compared against three popular pretreatment methods for N-glycan profiling (two were solid phase extraction and the other was acetone precipitation). The method's repeatability results showed that magnetic bead extraction has higher precision (% relative standard deviation (RSD), 0.121.06%) than solid phase extraction (SPE) (%RSD, 0.38-8.02%) and acetone precipitation (%RSD, 0.42-8.58%). This robust pretreatment method also maximized the retention of some low abundance oligosaccharides, and may thus provide a rapid and high-throughput workflow option for N-Glycan analysis in the biopharmaceutical industry.


Assuntos
Anticorpos Monoclonais/química , Cromatografia Líquida de Alta Pressão/métodos , Polissacarídeos , Proteínas Recombinantes/química , Anticorpos Monoclonais/análise , Imãs , Polissacarídeos/análise , Polissacarídeos/química , Proteínas Recombinantes/análise , Proteínas Recombinantes/normas , Reprodutibilidade dos Testes , Extração em Fase Sólida
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