Enhancement of Sensitivity on Miniaturized Thin-film Magnetoimpedance with Ellipsoidal Element

AbstractWe tried to control the distribution of the demagnetizing field inside magnetoimpedance elements fabricated using thin-film to gain higher sensitivity. Elements with quasi-ellipsoidal shape were adopted to modify the demagnetizing field distribution, because it is well known that the demagnetizing field is expected to be uniform in an ellipsoid. The larger impedance change and higher sensitivity were obtained in the ellipsoidal elements compared to those of the conventional rectangular elements. The observed results were analyzed by the calculations on the basis of the distribution of the demagnetizing field and the impedance profile without demagnetizing effect. The calculations well explained the experimental results: the improvement of sensitivity and the performance for the ellipsoidal elements is attributed to the uniform distribution of demagnetizing field. The experimental results demonstrate a potential and the calculation results contribute to optimum design, for a miniaturization of magnetoimpedance element in order to keep the higher sensitivity

Wireless Magnetic Motion Capture System for Multi-Marker Detection

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Conceptual Design of Rapid Circular Particle Accelerator Using High-Gradient Resonant Cavities with Fixed Frequency

A new high-energy particle accelerator with static combined type of magnetic field and high-gradient resonant cavities is introduced for muon acceleration up to 300 MeV and proton acceleration up to 400 MeV. The accelerator concept is expected to realize Mpps-class rapid cycling high-energy particle acceleration in circular particle accelerators. Conceptual designs of the circular accelerator are discussed with an emphasis on short lifetime particles. The fundamental concept of particle acceleration and the related practical issues, which should be discussed when designing the accelerators, are described as well

Discovery of widespread transcription initiation at microsatellites predictable by sequence-based deep neural network

Using the Cap Analysis of Gene Expression (CAGE) technology, the FANTOM5 consortium provided one of the most comprehensive maps of transcription start sites (TSSs) in several species. Strikingly, ~72% of them could not be assigned to a specific gene and initiate at unconventional regions, outside promoters or enhancers. Here, we probe these unassigned TSSs and show that, in all species studied, a significant fraction of CAGE peaks initiate at microsatellites, also called short tandem repeats (STRs). To confirm this transcription, we develop Cap Trap RNA-seq, a technology which combines cap trapping and long read MinION sequencing. We train sequence-based deep learning models able to predict CAGE signal at STRs with high accuracy. These models unveil the importance of STR surrounding sequences not only to distinguish STR classes, but also to predict the level of transcription initiation. Importantly, genetic variants linked to human diseases are preferentially found at STRs with high transcription initiation level, supporting the biological and clinical relevance of transcription initiation at STRs. Together, our results extend the repertoire of non-coding transcription associated with DNA tandem repeats and complexify STR polymorphism

Dumbbell-like Au–Fe3O4 nanoparticles for magnetic hyperthermia

Dumbbell-shaped hybrid nanoparticles, consisting of gold and iron oxide (Au-Fe3O4 NPs), show promise for magnetic hyperthermia cancer therapy. However, conventional synthesis methods using toxic iron pentacarbonyl (Fe(CO)5) raise safety concerns. We propose a safer approach using triiron dodecacarbonyl (Fe3(CO)12) as a precursor. We synthesize these NPs by initially reducing gold (III) chloride trihydrate with a tert-butylamine-borane complex at room temperature, yielding Au NPs. These Au NPs are combined with a Fe3(CO)12 solution and heated to 300 °C for 1 hour, resulting in the desired dumbbell-shaped Au-Fe3O4 NPs. Characterization confirms their morphology, with average sizes of 5 nm for Au NPs and 15 nm for Fe3O4 NPs. Our systematic evaluation of hydrophilic-treated Au-Fe3O4 NPs (Ms=49.5 emu/g at 3T, 300K) demonstrates temperature increases beyond the therapeutic threshold of 45 °C (ΔT=8 °C) at higher field strengths (8.6–30.0 kA/m), highlighting their cancer treatment potential. Quantitative analysis reveals superb performance, with a specific absorption rate (SAR) of 60.0 W/g and intrinsic loss power (ILP) of 0.25 nHm2kg−1 at the maximum field strength. These findings emphasize the significant potential of our dumbbell-shaped Au–Fe3O4 NPs for magnetic hyperthermia

Ferromagnetic resonance-based heat dissipation in dumbbell-like Au–Fe3O4 nanoparticles

Ferromagnetic resonance (FMR) holds promise for heating magnetic nanoparticles (MNPs) in cancer therapy, especially for rapidly heating MNPs. This study aims to enhance the FMR-based heating efficiency of multifunctional hybrid gold and iron oxide nanoparticles (Au-Fe3O4 NPs) as theranostic agents. We experimentally investigate the FMR-based heating properties of newly developed dumbbell-like Au-Fe3O4 NPs, which feature ∼5 nm gold and 15 nm iron oxide components, in comparison to our previously developed Au-coated Fe3O4 NPs (Fe3O4 core ∼5.2 nm, Au shell thickness ∼0.5 nm). For comparison, we also synthesize pure Fe3O4 NPs (∼11 nm) under the same experimental conditions as the dumbbell-like Au-Fe3O4 NPs but without 5 nm Au seeds. Temperature measurements are taken at various DC fields (HDC = 0‒1600 Oe) under a radiofrequency (RF) field (fAC = 4 GHz, HAC = 1.265 Oe) for ∼13s. The results reveal a rapid temperature rise during RF field ON, followed by a decline upon RF field OFF. Remarkably, dumbbell-like Au-Fe3O4 NPs achieve a peak temperature increase of 23.4 °C, corresponding to a heating rate of 1.73 °C/s at HDC = 400 Oe, surpassing the combined values of ∼11 nm Fe3O4 NPs (11.0 °C, i.e., 0.83 °C/s at HDC = 1000 Oe) and ∼5 nm Au NPs (3.5 °C). Comparing these results to our previously developed Au-coated Fe3O4 NPs, which achieved a heating rate of 1.29 °C/s (temperature rise 16.9 °C) under HDC = 1200 Oe with an RF field at fAC = 4 GHz and a significantly higher HAC = 4 Oe (i.e. for HAC = 1.265 Oe, the estimated heating rate was 0.129 °C/s with a temperature rise of 1.69 °C), the dumbbell-shaped Au-Fe3O4 NPs demonstrate a substantially higher temperature increase by 13.4 times. These findings highlight the exceptional potential of dumbbell-shaped Au-Fe3O4 NPs for application in magnetic hyperthermia