Magnetic Features Research Articles

Structural, magnetic and dielectric features of Cu, Al substituted Ca-hexaferrites for magnetic and energy applications

Structural, magnetic and dielectric features of Cu, Al substituted Ca-hexaferrites for magnetic and energy applications

Cardiac magnetic resonance imaging features of eosinophilic endocarditis: A case report

Cardiac magnetic resonance imaging features of eosinophilic endocarditis: A case report

Solar Flare Forecasting Using Hybrid Neural Networks

Abstract Solar flares are one of the most intense solar activities, the result of a sudden large-scale release of magnetic energy in the form of electromagnetic radiation and energetic particles. Intense solar flares can severely threaten communication and navigation systems, oil pipelines, and power grids on Earth. Therefore, it is crucial to establish highly accurate solar flare prediction models to enable humans to anticipate solar flare eruptions in advance, thereby reducing human and economic losses. In this paper, we utilized the solar active region (AR) magnetogram provided by the Solar Dynamics Observatory’s Helioseismic and Magnetic Imager and the associated feature parameters of the magnetic field; specifically, the feature vectors of the magnetic field’s spatial structure characteristics and the magnetic field feature parameters are fused to predict solar flares. We built two solar flare prediction models based on a combination of convolutional neural networks (CNN) and a temporal convolutional network (TCN), called CNN-TCN, and predicted whether a ≥C- or ≥M-class flare event would erupt in ARs in the next 24 hr, respectively. Then, after training and testing our model, we focused on the true skill statistic (TSS). Through the model superiority discussion, the model obtained high average TSS values, with the ≥C and ≥M models achieving TSS scores of 0.798 ± 0.032 and 0.850 ± 0.074, respectively, suggesting that our models have good forecasting performance. We speculate that some key features automatically extracted by our model may not have been previously identified, and these features could provide important clues for studying the mechanisms of flares.

Detection of magnetic skyrmion-like feature in the magnetocaloric properties of Gd2Ir0.97Si2.97

Detection of magnetic skyrmion-like feature in the magnetocaloric properties of Gd2Ir0.97Si2.97

Effect of heat treatment on structural and magnetic features of nanostructured Ni-Co-Mn-Al Heusler alloy obtained by planetary ball mills

Effect of heat treatment on structural and magnetic features of nanostructured Ni-Co-Mn-Al Heusler alloy obtained by planetary ball mills

Computed tomography and magnetic resonance imaging features of abdominal and pelvic leiomyomatosis peritonealis disseminata: A retrospective observational study.

Leiomyomatosis peritonealis disseminata (LPD) is a rare and specific type of leiomyomatosis that is often misdiagnosed as malignant tumor with peritoneal metastasis, and accurate diagnosis is critical to treatment planning. The purpose of this study is to investigate the radiological features of LPD, analyze, and summarize its differential diagnosis and clinical features to improve the understanding of this rare disease. A retrospective analysis was conducted on clinical and radiological features from 10 patients with pathologically confirmed LPD between 2012 and 2024. The computed tomography (CT) and magnetic resonance imaging (MRI) findings were examined, focusing on parameters such as location, morphology, size, quantity, enhancement patterns, and their relationship with adjacent organs. In addition, the radiological features and the key points of differential diagnosis were summarized. All the 10 LPD patients presented with multifocal lesions in the abdomen and pelvis, and 7 of them had a history of hysteromyoma surgery. The number of lesions was all ≥2, most of them were round or quasi-circular, with clear boundaries and smooth edges, did not invade the neighboring parenchymal organs, with a length of about 1.5~16.8 cm. The lesions were located in the pelvic cavity in 6 cases, the abdominal wall in 6 cases, the intestinal wall in 3 cases, the rectouterine pouch in 1 case, the omentum in 5 cases, the abdominal cavity in 1 case, and the mesentery in 1 case. There were 7 cases with minimal pelvic fluid and 1 case with liver spread. CT showed circular solid nodules with clear boundaries. The density of small lesions was homogeneous. Cystic changes were observed in some large lesions. On MRI, T1-weighted imaging showed hypo to isointense, T2-weighted imaging (T2WI) mostly showed hypointense, and T2WI in some large lesions showed slightly high signal intensity, diffusion-weighted imaging signal intensity was not higher than that of myometrium, apparent diffusion coefficient showed isointense, and solid components of the lesions were significantly more homogeneous enhanced after enhancement, and the enhancement degree was similar to that of normal myometrium. Although the imaging findings of LPD are similar to malignant tumors with peritoneal implantation and metastasis, they have certain characteristics, which are helpful for differential diagnosis combined with the clinical history of patients.

Multi-sequence magnetic resonance imaging radiomics combined with imaging features predicts the difficulty of HIFU treatment of uterine fibroids

To establish a multivariate linear regression model for predicting the difficulty of high-intensity focused ultrasound (HIFU) ablation of uterine fibroids based on multi-sequence magnetic resonance imaging radiomics features. A retrospective analysis was conducted on 218 patients with uterine fibroids who underwent HIFU treatment, including 178 cases from Yongchuan Hospital of Chongqing Medical University and 40 cases from the Second Affiliated Hospital of Chongqing Medical University (external validation set). Radiomics features were extracted and selected from magnetic resonance images, and potentially related imaging features were collected. The energy efficiency factor (EEF) was used as the dependent variable. Imaging models, radiomics models, and joint models were established using a stepwise approach. The model with the highest R2 value was selected for external validation. The R2 value of the combined model was 0.642, higher than that of other models. Spearman correlation analysis showed a correlation coefficient of R = 0.824 (P < 0.001) between predicted EEF and actual EEF. External validation yielded a correlation coefficient of R = 0.645 (P < 0.001). A model for predicting EEF has been developed, which is clinically important for predicting the difficulty of HIFU treatment of uterine fibroids.

Evaluating pulmonary stenosis and regurgitation impact on cardiac strain and strain rate in a porcine model via magnetic resonance feature tracking.

Pulmonary stenosis (PS) is common in congenital heart disease and an integral finding in Tetralogy of Fallot (TOF). Pulmonary regurgitation (PR) is more commonly found following surgery in repaired TOF. We aimed to evaluate the haemodynamic effects of PS and PR on cardiac physiology in a porcine model using cardiac magnetic resonance-based feature tracking (CMR-FT) deformation imaging. CMR-FT was performed in 14 pigs before and 10-12 weeks after surgery. Surgery included either pulmonary artery banding to simulate PS (n = 7), or an incision to the pulmonary valve to simulate PR (n = 7). CMR-FT assessment included left and right ventricular global longitudinal (LV/RV GLS) and LV circumferential (GCS) strain and strain rates (SR) as well as left and right atrial reservoir/conduit/booster pump (LA/RA Es, Ee, Ea) strain and SR. RV GLS was significantly reduced following PS compared to PR induction (PS -7.51 vs. PR -23.84, p < 0.001). RV GLS improved after induction of PR (before - 20.50 vs. after - 23.84, p = 0.018) as opposed to PS (before - 11.73 vs. after - 7.51, p = 0.128). Similarly, RA Es (PS 14.22 vs. PR 27.34, p = 0.017) and Ee (PS 8.65 vs. PR 20.51, p = 0.004) were decreased in PS compared to PR with detrimental impact of PS (Es before 23.20 vs. after 14.22, p = 0.018, Ee before 15.04 vs. after 8.65, p = 0.028) but not PR (Es before 31.65 vs. after 27.34, p = 0.176, Ee before 20.63 vs. after 20.51, p = 0.499). In a porcine model of RV pressure vs. volume overload, increased after- but not preload shows detrimental impact on RV and RA physiology.

Evaluation of sectional anatomic, micro-computed tomographic, and magnetic resonance imaging features of the thorax in Syrian hamsters (Mesocricetus auratus).

Clinically, the rodent thorax is important because of the variety of problems that may affect the heart, lungs, and other thoracic structures. Syrian hamsters are the most common pet and experimental hamster species. Sectional imaging of small mammals is widely increasing in use for clinical and research settings; however, no reports on the thoracic sectional imaging anatomy in this species have been made. Therefore, this study aimed at evaluating micro-computed tomography (MCT), magnetic resonance image (MRI), and gross sections of the Syrian hamster thorax. Eight healthy adult male and female Syrian hamsters were examined. Anesthetized hamsters were evaluated by MCT and 3 Tesla MRI. After imaging, the frozen slab sections were photographed, and identified anatomic structures were matched with structures on corresponding MCT and/or MRI images. Clinically relevant anatomic features of the Syrian hamster thorax that were identified on transverse and sagittal anatomic sections could be discerned on the corresponding MCT and MRI scans. The three matched images were exhibited the following features: (1) the narrow thoracic cavity and small lung space, (2) the heart positioning ventral and medial to lung, (3) heart ventricles locating towards the left side, and (4) parallel cardiac position relative to the sternum. The obtained results were similar to those have only been reported in rabbits, regardless of heart orientation and lung lobe covering the heart. The results of this study support the use of MCT and MRI as diagnostic tools in Syrian hamsters and provide reference values for the clinically relevant anatomic structures of thorax.

SMM Behavior in Distorted Trigonal Bipyramidal and Tetrahedral Cobalt(II) Complexes Based on Tripodal Tetradentate Phenolic Amines

Four CoII complexes [Co(L1)(MeOH)]‧MeOH (1‧MeOH), [Co(L2)(MeOH)]‧MeOH (2‧MeOH), [Co(L3)(H2O)]‧MeOH (3‧MeOH) and [Co(L4)] (4), derived from tripodal tetradentate phenolic amine arms, H2L1‐4, were synthesized and structurally characterized. The complexes 1·MeOH, 2·MeOH and 3·MeOH displayed distorted trigonal bipyramidal geometry, whereas 4 exhibited distorted tetrahedral geometry, depending on the substituents at the phenolate rings and amine arm. The variation of the coordination geometries and interatomic parameters around the CoII center has an impact on the magnetic behavior of the compounds. The complexes show magnetic anisotropy (ZFS) of the MS = ± ½ and ± 3/2 sub‐levels, with D = 29.1(2), 22.7(1), 28.8(2) and 30.9(5) cm‐1 for 1‧MeOH, 2‧MeOH, 3‧MeOH and 4, respectively. The results obtained from ab initio CASSF calculations match well with the experimental data, revealing the origin of magnetic anisotropy. The dynamic ac magnetic investigation of the magnetic susceptibility revealed a slow magnetic relaxation behavior for 2·MeOH, 3·MeOH and 4. The field‐induced slow relaxation of the magnetization occurred through combination of Raman and Direct processes, depending on the variation in the coordination geometries imposed by the coordinated ligand and/or the interatomic parameters around the CoII center, which in turn have definite impact on the magnetic features of the compounds.

Effect of Temperature on Magnetoimpedance Effect and Magnetic Properties of Fe- and Co-Rich Glass-Coated Microwires.

We provide new experimental studies of the temperature dependence of the giant magnetoimpedance (GMI) effect and hysteresis loops of Fe-rich and Co-rich amorphous microwires with rather different room temperature magnetic properties and GMI effect features. We observed a remarkable modification of hysteresis loops and magnetic field dependence of the GMI ratio upon heating in both of the studied samples. We observed a noticeable improvement in the GMI ratio and a change in hysteresis loops from rectangular to inclined upon heating in Fe-rich microwire. However, the opposite trend was observed in Co-rich microwire, in which, upon heating, the shape of the hysteresis loop changed from linear to rectangular. Generally, the evolution of the shape of the hysteresis loops during heating correlates with the modification of the dependencies of the GMI ratio ΔZ/Z on the magnetic field. For Co-rich microwire, the double-peak magnetic field dependence changed to single-peak, while for Fe-rich microwire, the opposite tendency was observed. The origin of the observed temperature dependences of the hysteresis loop and the GMI effect is discussed, considering internal stresses' relaxation during heating, the temperature dependencies of the magnetostriction coefficient, and internal stresses, as well as the Hopkinson effect.

Computed tomographic features and temporal evolution of the magnetic resonance imaging features of a resolving intracranial intraventricular hematoma in a dog.

An 11-year-old miniature pinscher presented for acute onset, seizure-like or syncopal episodes. Computed tomography of the head revealed a hyperattenuating, nonenhancing right lateral ventricular mass. Magnetic resonance imagingidentified a right lateral ventricular hemorrhagic mass associated with the choroid plexus and disseminated intraventricular and subarachnoid space hemorrhage. Subsequent MRI after 2 months was consistent with a resolving hematoma and residual abnormal choroid plexus conformation. Clinical signs resolved within 1 month on levetiracetam. To the author's knowledge, this is the first reported canine case of a resolving, intracranial, intraventricular hematoma on CT and repeat MRI.

Impact of pulmonary stenosis vs. regurgitation on strain and strain rate using cardiac magnetic resonance feature tracking in a porcine model

Impact of pulmonary stenosis vs. regurgitation on strain and strain rate using cardiac magnetic resonance feature tracking in a porcine model

Magnetic topology of quiet-Sun Ellerman bombs and associated ultraviolet brightenings

Context. Quiet-Sun Ellerman bombs (QSEBs) are small-scale magnetic reconnection events in the lower atmosphere of the quiet Sun. Recent work has shown that a small percentage of them can occur co-spatially and co-temporally with ultraviolet (UV) brightenings in the transition region. Aims. We aim to understand how the magnetic topologies associated with closely occurring QSEBs and UV brightenings can facilitate energy transport and connect these events. Methods. We used high-resolution Hβ observations from the Swedish 1-m Solar Telescope (SST) and detected QSEBs using k-means clustering. We obtained the magnetic field topology from potential field extrapolations using spectro-polarimetric data in the photospheric Fe I 6173 Å line. To detect UV brightenings, we used coordinated and co-aligned data from the Interface Region Imaging Spectrograph (IRIS) and imposed a threshold of 5σ above the median background on the (IRIS) 1400 Å slit-jaw image channel. Results. We identify four distinct magnetic configurations that associate QSEBs with UV brightenings, including a simple dipole configuration and more complex fan-spine topologies with a 3D magnetic null point. In the fan-spine topology, the UV brightenings occur near the 3D null point, while QSEBs can be found close to the footpoints of the outer spine, the inner spine, and the fan surface. The height of the 3D null varies between 0.2 Mm and 2.6 Mm, depending on the magnetic field strength in the region. Some QSEBs and UV brightenings, though occurring close to each other, are not topologically connected with the same reconnection process. The energy released during QSEBs falls in the range 1023–1024 ergs. Conclusions. This study shows that magnetic connectivity and topological features, such as 3D null points, are crucial in linking QSEBs in the lower atmosphere with UV brightenings in the transition region.

Comparative analysis of synthetic and conventional magnetic resonance imaging features across various brain regions

Comparative analysis of synthetic and conventional magnetic resonance imaging features across various brain regions

Study on the dosage of anthracycline drugs and its effect on left atrial and ventricular strain in children with leukemia: Based on cardiac magnetic resonance feature tracking technology

Study on the dosage of anthracycline drugs and its effect on left atrial and ventricular strain in children with leukemia: Based on cardiac magnetic resonance feature tracking technology

Evaluation of Chronic Myocardial Ischemic Scarring Through Strain Analysis Derived from Cardiac Magnetic Resonance Feature Tracking: Review Article

Evaluation of Chronic Myocardial Ischemic Scarring Through Strain Analysis Derived from Cardiac Magnetic Resonance Feature Tracking: Review Article

A Noncontact PCB Multifault Diagnosis Algorithm Based on Scalar Magnetic Field Fusion Feature and Transformer Architecture

A Noncontact PCB Multifault Diagnosis Algorithm Based on Scalar Magnetic Field Fusion Feature and Transformer Architecture

Left ventricle global longitudinal strain is a predictor of major adverse cardiovascular outcomes in patients with left ventricular non-compaction: Cardiac magnetic resonance feature tracking study

Left ventricle global longitudinal strain is a predictor of major adverse cardiovascular outcomes in patients with left ventricular non-compaction: Cardiac magnetic resonance feature tracking study

Enhanced magnetic resonance imaging features and management principles of low-grade myofibroblastic sarcoma of the breast: a case report

Enhanced magnetic resonance imaging features and management principles of low-grade myofibroblastic sarcoma of the breast: a case report