The magneto‐impedance (MI) effect was discovered about 30 years ago and a microsize magnetic sensor utilizing this effect has become commercially available. We make some modifications to the ...commercially available MI sensors to cover the dynamic range of the geomagnetic field. The total cost of three MI sensors for the two horizontal components and one vertical component including the modification is approximately one‐third of the standard price of triaxial fluxgate magnetometer sensors. For the period of 30 March to 27 April 2018, we conducted experimental observations of geomagnetic field variations with the MI sensor magnetometer (MIM) at the Mineyama observatory, which is located about 100 km northwest of Kyoto, Japan. Data obtained with the MIM are compared with those from the fluxgate magnetometer (FGM) that has been working at the observatory. Results show that the MIM can record geomagnetic field variations such as geomagnetic storm, solar quiet variations, low‐latitude positive bays, storm sudden commencement, and long‐period geomagnetic pulsations with a peak‐to‐peak amplitude of ≤1 nT that is also detected with the FGM. Power spectra of the geomagnetic field variations measured with the MIM and FGM are almost the same. It is found that the MIM has a larger temperature drift than the FGM. The present study reveals that the MIM is comparable to the FGM in measuring the geomagnetic field variations in a period from a few tens of seconds to a few hours and is useful for researches in upper atmospheric physics or space physics.
Key Points
Magneto‐impedance (MI) sensor is applied for the first time to geomagnetic field measurement at the low‐latitude Mineyama observatory
MI sensor magnetometer (MIM) can record magnetic storm, storm sudden commencement, solar quiet, low‐latitude positive bay, and long period geomagnetic pulsations
MIM is compared to fluxgate magnetometer in measuring geomagnetic field variations with periods from 10s of seconds to a few hours
•A low-cost Bluetooth–based wireless neuronal recording system was fabricated.•The wireless system weighted <3.9 g with the battery and measured 15 × 15 × 12 mm3.•In vivo acute and chronic recordings ...using mice confirm the recording capabilities.•The wireless system improves the recording quality compared to wired recording.
Electrophysiological recording, which has made significant contributions to the field of neuroscience, can be improved in terms of signal quality, invasiveness, and use of cables. Although wireless recording can meet these requirements, conventional wireless systems are relatively heavy and bulky for use in small animals such as mice. This study developed a low-cost Bluetooth low-energy (BLE)-based wireless neuronal recording system weighing <3.9 g and measuring 15 × 15 × 12 mm3, with easy assembly, good versatility, and high signal quality for recordings. Both acute and chronic in vivo recordings of mice confirm the wireless recording capabilities of the system, with improvements in terms of the power spectral density (PSD) and signal-to-noise ratio (SNR) compared with wired recording. Because of its low weight and compactness, the BLE-based wireless neuronal recording system can be used not only in mice but also in other animals, such as rats and monkeys, thus expanding the application of electrophysiological recordings in neuroscience.
The accident of the Fukushima Dai-ichi nuclear power plant in March 2011 released a large amount of radiocesium into the North Pacific Ocean. Vertical distributions of Fukushima-derived radiocesium ...were measured at stations along the 149°E meridian in the western North Pacific during the winter of 2012. In the subtropical region, to the south of the Kuroshio Extension, we found a subsurface radiocesium maximum at a depth of about 300 m. It is concluded that atmospheric-deposited radiocesium south of the Kuroshio Extension just after the accident had been transported not only eastward along with surface currents but also southward due to formation/subduction of subtropical mode waters within about 10 months after the accident. The total amount of decay-corrected (134)Cs in the mode water was an estimated about 6 PBq corresponding to 10-60% of the total inventory of Fukushima-derived (134)Cs in the North Pacific Ocean.
•We fabricated a flexible parylene-thread bioprobe and proposed the implantation method based on conventional sewing method.•A device-holding protocol was proposed to enable a stress-free “catch” and ...“release” of the needle.•EMG signals were recorded from the mouse’s MG muscle.•Both the LFP and the spike were recorded from the mouse’s visual cortex in in vivo chronic recording.
Multichannel recording of the electrical signals from soft biological tissue of brain is an important technique in electrophysiology. However, penetration of conventional rigid needle-electrodes causes physical-stress to the tissue and induces the tissue damage, making the stable recording impossible. The approach reported here involves the use of a flexible “thread-like” device with microelectrodes that enables precise penetration and placement inside the brain tissue, with the help of a guiding microneedle, similar to sewing mechanism. A device-holding protocol, which uses a dissolvable material, is proposed to enable a stress-free “catch” and “release” of the needle. The device is placed in the primary visual cortex (V1) of an in vivo mouse and both the local field potentials (LFP) and the action potentials (spike) are recorded. For over a period of two weeks after device implantation, no remarkable decrease in mouse’s weight is observed. Therefore, we conclude that the proposed sewing thread-device enhances the recording of neuronal signals while minimizing the device–induced stress.
Abstract
We expanded the batch-to-batch offsets of The International Association for the Physical Sciences of the Oceans (IAPSO) Standard Seawater (SSW) batches P145–P163 by intercomparison ...measurements using salinometers. On the basis of our results, we recommend using the correction factors instead of the offsets to correct the batch-to-batch differences, especially for salinity data outside the range of 30–40 g kg
−1
. We evaluated the expanded batch-to-batch correction factors by applying them to time series salinity data collected in the northwestern North Pacific Ocean and found that they are effective for detecting recent freshening (−0.6 ± 0.1 × 10
−3
g kg
−1
decade
−1
) in the deep North Pacific, which might be related to a reduction of the formation rate of Antarctic Bottom Water. We also evaluated the SSW linearity pack by applying the batch-to-batch correction factors. Linearity errors of the salinometers estimated from decade resistance substituters were consistent with the results of the linearity pack measurements. To correct the linearity errors of a salinometer, it might be suitable to use the more detailed distribution of those estimated from the decade resistance substituter than the linearity pack measurements. Since the cause of large batch-to-batch differences is still unclear, a reference seawater that is more robust and stable than SSW might be necessary to establish a high-level of international comparability of salinity measurements; the Multiparametric Standard Seawater (MSSW) currently under development might be a candidate for such reference seawater, because MSSW is expected to be more stable than SSW not only in practical salinity but also in absolute salinity.
Abnormal oscillatory brain activities are commonly observed in neurological and psychiatric disorders including epilepsy, Parkinson's disease, Alzheimer's disease, schizophrenia, ...anxiety/trauma-related disorders, major depressive disorders, and addiction (Leuchter et al., 2015; Takeuchi et al., 2021b). ...these disorders can be considered as common oscillation defects “oscillopathies,” despite having distinct behavioral manifestations (Takeuchi and Berényi, 2020; Földi et al., 2021). Wada et al. reported diminished “rubber tail task”-related expression of the immediate early gene (c-Fos) in the posterior parietal cortex of a transgenic mouse line that exhibits autistic-like phenotypes. Commun. 9, 483. doi: 10.1038/s41467-018-02928-3 Yuichi Takeuchi1,2*, Qun Li2, Takeshi Kawano3, Jun Nagai4 and Tatsuya Mima5 * 1Department of Biopharmaceutical Sciences and Pharmacy, Faculty of Pharmaceutical Sciences, Hokkaido University, Sapporo, Japan * 2MTA-SZTE “Momentum” Oscillatory Neuronal Networks Research Group, Department of Physiology, University of Szeged, Szeged, Hungary * 3Department of Electrical and Electronic Information Engineering, Toyohashi University of Technology, Aichi, Japan * 4Laboratory for Glia-Neuron Circuit Dynamics, RIKEN Center for Brain Science, Saitama, Japan * 5The Graduate School of Core Ethics and Frontier Sciences, Ritsumeikan University, Kyoto, Japan
The MUC1 heterodimeric transmembrane glycoprotein is aberrantly overexpressed by diverse human carcinomas. Galectin-3 is a β-galactoside binding protein that has also been associated with the ...development of human cancers. The present results demonstrate that MUC1 induces galectin-3 expression by a posttranscriptional mechanism. We show that the MUC1 C-terminal subunit is glycosylated on Asn-36 and that this modification is necessary for upregulation of galectin-3. N-glycosylated MUC1-C increases galectin-3 mRNA levels by suppressing expression of the microRNA miR-322 and thereby stabilizing galectin-3 transcripts. The results show that, in turn, galectin-3 binds to MUC1-C at the glycosylated Asn-36 site. The significance of the MUC1-C-galectin-3 interaction is supported by the demonstration that galectin-3 forms a bridge between MUC1 and the epidermal growth factor receptor (EGFR) and that galectin-3 is essential for EGF-mediated interactions between MUC1 and EGFR. These findings indicate that MUC1 and galectin-3 function as part of a miR-322-dependent regulatory loop.
Gold nanoparticle (AuNP)-embedded collagen gels have been prepared as a visible light-responsive cell scaffold that is applied to a visible light-induced in situ single cell detachment system. In ...this study, the visible light-responsive cell scaffold is combined with microarray technology for high-throughput cell separation. The AuNP-embedded collagen gel microarrays were prepared by pressing microarrays with 200 μm pores into the AuNP-embedded collagen gel. The microsized AuNP-embedded collagen gel was downsized to one thousandth of the conventional gel produced in a 96-well plate. Efficient thermal deformation of the microsized collagen gel was exhibited after laser irradiation for several seconds, which suggested that the microsized collagen gels had high sensitivity to the photothermogenic property. A collagen gel microarray with an AuNP coating at the bottom was also prepared; this exhibited morphological change after a shorter laser irradiation period than the AuNP-embedded collagen gel microarray. The cells cultured on the AuNP-embedded collagen gels were dead after laser irradiation but still alive on the collagen gel with the AuNP coating at the bottom. Thus, the AuNP-coated collagen gel microarray might work as a cell-friendly visible light-induced in situ single cell detachment system.
•A low impedance and high charge-injection material with an enhanced surface area is proposed.•A layer-by-layer assembly of IrOx/Pt-black with nanoroughness is fabricated.•IrOx/Pt-black has half the ...impedance and 2.4 times QCDC of a same-sized flat-IrOx.•In vivo electrical stimulation of the sciatic nerve of a mouse is demonstrated using a low voltage IrOx/Pt-black plated microelectrode.
Electrical neural stimulating electrodes play an important role in medical applications and improving health/medical conditions. However, size reduction for low-invasive electrodes creates issues with high electrolyte/electrode interfacial impedance and low charge-injection characteristics, which makes it impossible to stimulate neurons/cells. To overcome these limitations, we propose an electrode material for low-voltage microscale electrode neurostimulation that combines the advantages of low impedance of iridium oxide (IrOx) with the enhanced surface area of platinum black (Pt-black). Based on a simple, rapid, low-temperature electroplating process, herein a low impedance and high charge-injection electrode is fabricated by a layer-by-layer assembly of IrOx/Pt-black with nanoscale roughness. The assembled nanorough-IrOx/Pt-black electrode has an impedance of 32 Ωcm2 at 1kHz and a charge-injection delivery capacity (QCDC) of 46.7mCcm−2, which are 0.5 and 2.4 times the values for the same-sized IrOx/flat-Pt electrode, respectively. The stimulation capability of the nanorough-IrOx/Pt-black plated microelectrode is confirmed by in vivo stimulations of the sciatic nerve of a mouse. The threshold voltages of 8-μm-diameter and 11-μm-diameter electrodes are 700mV and 300mV, respectively. However, increasing the diameter of high QCDC nanorough-IrOx/Pt-black can further reduce the stimulation voltage. Consequently, nanorough-IrOx/Pt-black is applicable to low-voltage microscale electrode neurostimulations for powerful in vivo/in vitro electrophysiological measurements.
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