A wearable self-powered active sensor for respiration and healthcare monitoring was fabricated based on a flexible piezoelectric nanogenerator. An electrospinning poly(vinylidene fluoride) thin film on silicone substrate was polarized to fabricate the flexible nanogenerator and its electrical property was measured. When periodically stretched by a linear motor, the flexible piezoelectric nanogenerator generated an output open-circuit voltage and short-circuit current of up to 1.5 V and 400 nA, respectively. Through integration with an elastic bandage, a wearable self-powered sensor was fabricated and used to monitor human respiration, subtle muscle movement, and voice recognition. As respiration proceeded, the electrical output signals of the sensor corresponded to the signals measured by a physiological signal recording system with good reliability and feasibility. This self-powered, wearable active sensor has significant potential for applications in pulmonary function evaluation, respiratory monitoring, and detection of gesture and vocal cord vibration for the personal healthcare monitoring of disabled or paralyzed patients.
2Cosmic-ray-muon spallation-induced radioactive isotopes with β decays are one of the major backgrounds for solar, reactor, and supernova relic neutrino experiments. Unlike in scintillator, production yields for cosmogenic backgrounds in water have not been exclusively measured before, yet they are becoming more and more important in next generation neutrino experiments designed to search for rare signals. We have analyzed the low-energy trigger data collected at Super-Kamiokande-IV in order to determine the production rates of 12 B, 12 N, 16 N, 11 Be, 9 Li, 8 He, 9 C, 8 Li, 8 B and 15 C. These rates were extracted from fits to time differences between parent muons and subsequent daughter β's by fixing the known isotope lifetimes. Since 9 Li can fake an inverse-beta-decay reaction chain via a β + n cascade decay, producing an irreducible background with detected energy up to a dozen MeV, a dedicated study is needed for evaluating its impact on future measurements; the application of a neutron tagging technique using correlated triggers was found to improve this 9 Li measurement. The measured yields were generally found to be comparable with theoretical calculations, except the cases of the isotopes 8 Li/ 8 B and 9 Li.
Artículo escrito por muchos autores, sólo se referencian el primero, los autores que firman como Universidad Autónoma de Madrid y el grupo de colaboración en el caso de que aparezca en el artículoSearch results for nucleon decays p→e+X, p→μ+X, n→νγ (where X is an invisible, massless particle) as well as dinucleon decays np→e+ν, np→μ+ν, and np→τ+ν in the Super-Kamiokande experiment are presented. Using single-ring data from an exposure of 273.4 kton·yr, a search for these decays yields a result consistent with no signal. Accordingly, lower limits on the partial lifetimes of τp→e+X>7.9×1032yr, τp→μ+X>4.1×1032yr, τn→νγ>5.5×1032yr, τnp→e+ν>2.6×1032yr, τnp→μ+ν>2.2×1032yr, and τnp→τ+ν>2.9×1031yr at a 90% confidence level are obtained. Some of these searches are novelThe Super- Kamiokande experiment was built and has been operated with funding from the Japanese Ministry of Education, Culture, Sports, Science and Technology, the U.S. Department of Energy, and the U.S. National Science Foundatio
Most osteoporosis treatment candidates remained untreated. Men, black patients, and patients with fracture or chronic comorbidities were less likely to receive treatment, representing disparity in the recognition and treatment of osteoporosis.
We report the results from a search in Super-Kamiokande for neutrino signals coincident with the first detected gravitational-wave events, GW150914 and GW151226, as well as LVT151012, using a neutrino energy range from 3.5 MeV to 100 PeV. We searched for coincident neutrino events within a time window of ±500 s around the gravitational-wave detection time. Four neutrino candidates are found for GW150914, and no candidates are found for GW151226. The remaining neutrino candidates are consistent with the expected background events. We calculated the 90% confidence level upper limits on the combined neutrino fluence for both gravitational-wave events, which depends on event energy and topologies. Considering the upward-going muon data set (1.6 GeV–100 PeV), the neutrino fluence limit for each gravitational-wave event is 14–37 (19–50) cm−2 for muon neutrinos (muon antineutrinos), depending on the zenith angle of the event. In the other data sets, the combined fluence limits for both gravitational-wave events range from 2.4 × 104 to 7.0 × 109 cm−2.
Motor-evoked potentials (MEP) are one of the most important responses to brain stimulation, such as supra-threshold transcranial magnetic stimulation (TMS) and electrical stimulation. The understanding of the neurophysiology and the determination of the lowest stimulation strength that evokes responses requires the detection of even smallest responses, e.g., from single motor units, but available detection and quantization methods are rather simple and suffer from a large noise floor. The paper introduces a more sophisticated matched-filter detection method that increases the detection sensitivity and shows that activation occurs well below the conventional detection level. In consequence, also conventional threshold definitions, e.g., as 50 µV median response amplitude, turn out to be substantially higher than the point at which first detectable responses occur.The presented method uses a matched-filter approach for improved sensitivity and generates the filter through iterative learning from the presented data. In contrast to conventional peak-to-peak measures, the presented method has a higher signal-to-noise ratio (≥14 dB). For responses that are reliably detected by conventional detection, the new approach is fully compatible and provides the same results but extends the dynamic range below the conventional noise floor. The underlying method is applicable to a wide range of well-timed biosignals and evoked potentials, such as in electroencephalography. I. INTRODUCTIONMotor-evoked potentials (MEP) are an important response phenomenon in brain stimulation. If motoneurons in the primary motor cortex are activated directly or indirectly, they respond with action potentials, which are transmitted down the spinal cord to the lower motoneurons [1,2]. The lower motoneurons route the signals to the muscles, where they can be detected as MEP waves through electromyography (EMG). MEPs provide one of the few directly observable responses of the brain to stimuli and individualize the stimulation strength. Furthermore, MEPs are a key to understanding the biophysical and neurophysiological mechanisms of brain stimulation, to establishing safety limits, and to achieving individual dosing [3,4]. In FDA-approved treatment with transcranial magnetic stimulation (TMS), for instance, the so-called motor threshold is defined based on MEPs and is the key safety as well as dosage parameter [5].
Integration of an organic photovoltaic (PV) with carbon-based supercapacitors (SCs) into a system for solar energy harvesting and storage is interesting for off-grid applications such as mobile electronics and sensor systems. Presented here is a conversion and control circuit (CC) on a flexible polyimide substrate in an integrated flexible energy harvesting and storage device compatible with roll-to-roll manufacturing (R2R). The CC is capable of PV max power-point tracking, DC-DC voltage boost of the PV output across a bank of four SCs, and charge balancing across the bank of SCs. This system is compared to a conventional direct connection between the PV and the SCs. More energy can be harvested from the PV and stored in the SC bank when using the CC to drive the PV at peak power, boost the output voltage, and balance it across serial connection of SCs. Finally, the CC, PV, and SCs are mounted to a 3D printed substrate and circuit which is used to power a wearable sensor. Due to these benefits and ability to be integrated with R2R, the presented CC provides a practical means of improving wearable solar energy harvesting and storage systems. In the flexible electronics literature, multiple publications demonstrated novel energy materials and devices, such as thin-film flexible photovoltaics (PVs)1-10 and carbon-based supercapacitors (SCs) [11][12][13][14][15][16][17][18] that are roll-to-roll (R2R) compatible. A few publications have further integrated a PV material with SCs to form an energy device capable of solar energy harvest and storage. 17,[19][20][21][22][23][24] Although simply connecting the devices without a conversion and control circuit (CC) that controls the flow of charge and the load impedance experienced by the PV can harvest and store energy, there are three problems that arise from this configuration: (i) the PV elements are operated inefficiently at suboptimal voltage-current conditions, far from the maximum-power point (MPP), (ii) undercharging the SCs due to low PV output voltage, and (iii) unbalanced charge storage across a bank of SCs with the risk of overcharging some while undercharging other SCs as well as a low usable combined capacity. These problems result in an inefficient and impractical energy device. In large PV systems, a CC typically mitigates these problems. However, such CCs use a discrete design with stiff bus bars or rigid circuit boards, which are incompatible with the flexible film design of the rest of the system. The lack of availability of a R2R-compatible CC has limited the realization of a R2R energy fabric for practical applications such as wearable sensors and the internet of things (IoT). 25 Many techniques have been developed to enable R2R-compatible packaging of CCs. Within the CC architecture, switching-mode DC-DC boost converters have been given considerable attention. For example, Z-folded flexible planar transformers have been developed that allow R2R production. 26 Planar geometries of flexible foils for use as low-profile inductors 27 and flip-chip flex-ci...
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.