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Article ; Online: Identification of ring current proton precipitation driven by scattering of electromagnetic ion cyclotron waves

Binbin Ni / Yang Zhang / Xudong Gu

Fundamental Research, Vol 3, Iss 2, Pp 257-

2023 Volume 264

Abstract: Among the most intense emissions in the Earth's magnetosphere, electromagnetic ion cyclotron (EMIC) waves are regarded as a critical candidate contributing to the precipitation losses of ring current protons, which however lacks direct multi-point ... ...

Abstract	Among the most intense emissions in the Earth's magnetosphere, electromagnetic ion cyclotron (EMIC) waves are regarded as a critical candidate contributing to the precipitation losses of ring current protons, which however lacks direct multi-point observations to establish the underlying physical connection. Based upon a robust conjunction between the satellite pair of Van Allen Probe B and NOAA-19, we perform a detailed analysis to capture simultaneous enhancements of EMIC waves and ring current proton precipitation. By assuming that the ring current proton precipitation is mainly caused by EMIC wave scattering, we establish a physical model between the wave-driven proton diffusion and the ratio of precipitated-to-trapped proton count rates, which is subsequently applied to infer the intensity of EMIC waves required to cause the observed proton precipitation. Our simulations indicate that the model results of EMIC wave intensity, obtained using either the observed or empirical Gaussian wave frequency spectrum, are consistent with the wave observations, within a factor of 1.5. Our study therefore strongly supports the dominant contribution of EMIC waves to the ring current proton precipitation, and offers a valuable means to construct the global profile of EMIC wave intensity using low-altitude NOAA POES proton measurements, which generally have a broad L-shell coverage and high time resolution in favor of near-real-time conversion of the global EMIC wave distribution.
Keywords	Electromagnetic ion cyclotron waves ; Ring current protons ; Wave-particle interactions ; Conjugate observations ; Precipitation losses ; Science (General) ; Q1-390
Subject code	535
Language	English
Publishing date	2023-03-01T00:00:00Z
Publisher	KeAi Communications Co. Ltd.
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article ; Online: A new hand function assessment method using an infrared imaging device.

Qinag Fang / Xudong Gu

Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Annual International Conference

2017 Volume 2017, Page(s) 1571–1574

Abstract: Many post-stroke patients suffer various degrees of hand function and fine motor skills impairment. Both passive and active hand rehabilitation training are beneficial in improving strength and dexterity of hands. However, hand rehabilitation programs ... ...

Abstract	Many post-stroke patients suffer various degrees of hand function and fine motor skills impairment. Both passive and active hand rehabilitation training are beneficial in improving strength and dexterity of hands. However, hand rehabilitation programs should be prescribed, based on an accurate assessment of hand function. Here we propose a novel method for hand function assessment that can accurately measure multiple joint angles of a hand simultaneously using a portable infrared imaging device. Different from the traditional assessment methods that are often based on clinicians' subjective observation and ordinal charts, this method provides an accurate, fast and objective evaluation using infrared imaging sensors. This novel hand function assessment method can be used to replace the currently popularly used traditional method for fine hand function modeling and assessment in rehabilitation medicine and can play an important role in precision post-stroke function analysis.
MeSH term(s)	Hand ; Hand Strength ; Humans
Language	English
Publishing date	2017-10-20
Publishing country	United States
Document type	Journal Article
ISSN	2694-0604
ISSN (online)	2694-0604
DOI	10.1109/EMBC.2017.8037137
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Article ; Online: Surface electromyography based muscle fatigue analysis for stroke patients at different Brunnstrom stages.

Yinjun Tu / Zhe Zhang / Xudong Gu / Qiang Fang

Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Annual International Conference

2017 Volume 2016, Page(s) 3781–3784

Abstract: Muscle fatigue analysis has been an important topic in sport and rehabilitation medicine due to its role in muscle performance evaluation and pathology investigation. This paper proposes a surface electromyography (sEMG) based muscle fatigue analysis ... ...

Abstract	Muscle fatigue analysis has been an important topic in sport and rehabilitation medicine due to its role in muscle performance evaluation and pathology investigation. This paper proposes a surface electromyography (sEMG) based muscle fatigue analysis approach which was specifically designed for stroke rehabilitation applications. 14 stroke patients from 5 different Brunnstrom recovery stage groups were involved in the experiment and features including median frequency and mean power frequency were extracted from the collected sEMG samples for investigation. After signal decomposition, the decline of motor unit firing rate of patients from different groups had also been studied. Statistically significant presence of fatigue had been observed in deltoideus medius and extensor digitorum communis of patients at early recovery stages (P<;0.05) and no similar observation had been obtained for patients at later stages (P>0.01). It had also been discovered that the motor unit firing frequency declines with a range positively correlated to the recovery stage during repetitive movements. Based on the experiment result, it can be verified that as the recovery stage increases, the central nervous system's control ability strengthens and the patient motion becomes more stable and resistive to fatigue.
MeSH term(s)	Aged ; Electromyography/methods ; Female ; Hand/physiology ; Humans ; Male ; Middle Aged ; Muscle Fatigue/physiology ; Muscle, Skeletal/physiology ; Muscle, Skeletal/physiopathology ; Signal Processing, Computer-Assisted ; Stroke/physiopathology ; Stroke Rehabilitation
Language	English
Publishing date	2017-03-07
Publishing country	United States
Document type	Journal Article
ISSN	2694-0604
ISSN (online)	2694-0604
DOI	10.1109/EMBC.2016.7591551
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Article ; Online: Statistical Analysis of Lunar 1 Hz Waves Using ARTEMIS Observations

Yuequn Lou / Xudong Gu / Xing Cao / Mingyu Wu / Sudong Xiao / Guoqiang Wang / Binbin Ni / Tielong Zhang

The Astrophysical Journal, Vol 943, Iss 1, p

2023 Volume 17

Abstract: Like 1 Hz waves occurring in the upstream of various celestial bodies in the solar system, 1 Hz narrowband whistler-mode waves are often observed around the Moon. However, wave properties have not been thoroughly investigated, which makes it difficult to ...

Abstract	Like 1 Hz waves occurring in the upstream of various celestial bodies in the solar system, 1 Hz narrowband whistler-mode waves are often observed around the Moon. However, wave properties have not been thoroughly investigated, which makes it difficult to proclaim the generation mechanism of the waves. Using 5.5 yr wave data from ARTEMIS, we perform a detailed investigation of 1 Hz waves in the near-lunar space. The amplitude of lunar 1 Hz waves is generally 0.05–0.1 nT. In the geocentric solar ecliptic coordinates, the waves show no significant regional differentiation pattern but show an absence inside the magnetosphere. Correspondingly, in the selenocentric solar ecliptic coordinates, the waves can occur extensively at ∼1.1–12 R _L , while few events are observed in the lunar wake due to a lack of interaction with the solar wind. Furthermore, the wave distributions exhibit modest day–night and dawn–dusk asymmetries but less apparent north–south asymmetry. Compared with the nightside, more intense waves with lower peak wave frequency are present on the dayside. The preferential distribution of 1 Hz waves exhibits a moderate correlation with strong magnetic anomalies. The waves propagate primarily at wave normal angles <60° with an ellipticity of [−0.8, −0.3]. For stronger wave amplitudes and lower latitudes, 1 Hz waves generally have smaller wave normal angles and become more left-hand circularly polarized. Owing to the unique interaction between the Moon and solar wind, our statistical results might provide new insights into the generation mechanism(s) of 1 Hz waves in planetary plasma environments and promote the understanding of lunar plasma dynamics.
Keywords	Solar wind ; Space plasmas ; Lunar science ; Shocks ; Astrophysics ; QB460-466
Subject code	535 ; 551
Language	English
Publishing date	2023-01-01T00:00:00Z
Publisher	IOP Publishing
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article ; Online: A Comparative Study of VLF Transmitter Signal Measurements and Simulations during Two Solar Eclipse Events

Wen Cheng / Wei Xu / Xudong Gu / Shiwei Wang / Qingshan Wang / Binbin Ni / Zilong Lu / Binxiao Xiao / Xiaoyu Meng

Remote Sensing, Vol 15, Iss 3025, p

2023 Volume 3025

Abstract: To monitor the Very-Low-Frequency (VLF) environment, a VLF detection system has been installed in Suizhou, China, a location with the longitude almost identical to that of the NWC transmitter in Australia. In the years 2019 and 2020, two solar eclipses ... ...

Abstract	To monitor the Very-Low-Frequency (VLF) environment, a VLF detection system has been installed in Suizhou, China, a location with the longitude almost identical to that of the NWC transmitter in Australia. In the years 2019 and 2020, two solar eclipses crossed the NWC–Suizhou path at different locations. Each solar eclipse event represents a naturally occurring controlled experiment, but these two events are unique in that similar levels of electron density variation occurred at different locations along the VLF propagation path. Therefore, we conducted a comparative study using the VLF measurements during these two eclipses. Previous studies mostly estimated a pair of the reflection height ( h ′) and sharpness parameter ( β ) using the Long Wavelength Propagation Capability code, whereas, in this study, we use the VLF amplitude and phase as constraints in order to find the electron density change that best explains the VLF measurements. The eclipse measurements could be best explained if the path-averaged β value was 0.56 and 0.62 km −1 for the 2019 and 2020 eclipse, respectively. The VLF reflection height increased from 71.5 to 73.3 km for the 2019 eclipse and from 71.1 to 72.8 km for the 2020 eclipse. The best-fit β values were consistent with the Faraday International Reference Ionosphere model and statistical studies, and the h ′ change was also consistent with previous studies and theoretical calculations. Moreover, present results suggested that VLF signals collected by a single receiver were not sensitive to where the electron density change occurs along the propagation path but reflected the average path condition. Therefore, a network of VLF receivers is required in order to monitor in real time the spatial extent of the space weather events that disturb the lower ionosphere.
Keywords	VLF remote sensing ; D -region ionosphere ; solar eclipse ; lower ionosphere ; FDTD modeling ; sub ionospheric remote sensing ; Science ; Q
Subject code	621
Language	English
Publishing date	2023-06-01T00:00:00Z
Publisher	MDPI AG
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article: Effects of nitrogen and phosphorus addition on growth and leaf nitrogen metabolism of alfalfa in alkaline soil in Yinchuan Plain of Hetao Basin.

Xudong, Gu / Fengju, Zhang / Teng, Wang / Xiaowei, Xie / Xiaohui, Jia / Xing, Xu

PeerJ

2022 Volume 10, Page(s) e13261

Abstract: Alkaline soil is widely distributed in China. Its rational utilization is an effective measure to solve land shortage and improve the environment. Alfalfa is characterized by strong salt and alkali tolerance and high yield and protein content. Nitrogen ( ... ...

Abstract	Alkaline soil is widely distributed in China. Its rational utilization is an effective measure to solve land shortage and improve the environment. Alfalfa is characterized by strong salt and alkali tolerance and high yield and protein content. Nitrogen (N) and phosphorus (P) are the main nutrients for plant growth, and N metabolism is one of the primary forms of plant metabolism, which plays a vital role in quality and yield formation. The exploration of the effect of N and P on N metabolism and alfalfa growth will provide a theoretical basis for scientific fertilization for alfalfa in the alkaline soil of the Yinchuan Plain of the Hetao Basin. Therefore, a 2-year experiment of N and P addition was conducted. Six treatments were set up with a randomized block design, including without N (WN), medium N (MN), high N (HN), without P (WP), medium P (MP), and high P (HP). It was found that the MN and MP treatments increased plant height, stem diameter, stem/leaf, dry/fresh, and dry matter of alfalfa. The HN and HP treatments inhibited alfalfa biomass formation. The MN and MP treatments increased key products and enzymes of leaf N metabolism of alfalfa and promoted activities of leaf nitrate reductase (NR), glutamine synthase (GS), glutamate synthase (GOGAT), glutamic-oxalacetic transaminase (GOT), and glutamic-pyruvate transaminase (GPT), and inhibited activities of leaf protease of alfalfa. The MN and MP treatments increased contents of leaf N, P, ammonium nitrogen (NH
Language	English
Publishing date	2022-04-13
Publishing country	United States
Document type	Journal Article
ZDB-ID	2703241-3
ISSN	2167-8359
ISSN	2167-8359
DOI	10.7717/peerj.13261
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Article ; Online: Occupational Therapy Assessment for Upper Limb Rehabilitation

Seedahmed S. Mahmoud / Zheng Cao / Jianming Fu / Xudong Gu / Qiang Fang

Frontiers in Digital Health, Vol

A Multisensor-Based Approach

2021 Volume 3

Abstract: Most post-stroke patients experience varying degrees of impairment in upper limb function and fine motor skills. Occupational therapy (OT) with other rehabilitation trainings is beneficial in improving the strength and dexterity of the impaired upper ... ...

Abstract	Most post-stroke patients experience varying degrees of impairment in upper limb function and fine motor skills. Occupational therapy (OT) with other rehabilitation trainings is beneficial in improving the strength and dexterity of the impaired upper limb. An accurate upper limb assessment should be conducted before prescribing upper limb OT programs. In this paper, we present a novel multisensor method for the assessment of upper limb movements that uses kinematics and physiological sensors to capture the movement of the limbs and the surface electromyogram (sEMG). These sensors are Kinect, inertial measurement unit (IMU), Xsens, and sEMG. The key assessment features of the proposed model are as follows: (1) classification of OT exercises into four classes, (2) evaluation of the quality and completion of the OT exercises, and (3) evaluation of the relationship between upper limb mobility and muscle strength in patients. According to experimental results, the overall accuracy for OT-based motion classification is 82.2%. In addition, the fusing of Kinect and Xsens data reveals that muscle strength is highly correlated with the data with a correlation coefficient (CC) of 0.88. As a result of this research, occupational therapy specialists will be able to provide early support discharge, which could alleviate the problem of the great stress that the healthcare system is experiencing today.
Keywords	assessment ; inertial measurement unit ; kinect ; occupational therapy ; surface electromyograph ; upper limb ; Medicine ; R ; Public aspects of medicine ; RA1-1270 ; Electronic computers. Computer science ; QA75.5-76.95
Subject code	796
Language	English
Publishing date	2021-12-01T00:00:00Z
Publisher	Frontiers Media S.A.
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article ; Online: Hot Plasma Effects on the Cyclotron-Resonant Pitch-Angle Scattering Rates of Radiation Belt Electrons Due to EMIC Waves

Binbin Ni / Xing Cao / Yuri Shprits / Danny Summers / Xudong Gu / Song Fu / Yuequn Lou

Geophysical Research Letters

2018

Publishing country	de
Document type	Article ; Online
DOI	10.1002/2017GL076028
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article ; Online: Resonance zones for interactions of magnetosonic waves with radiation belt electrons and protons

Wenxun Zhang / Ruoxian Zhou / Juan Yi / Xudong Gu / Binbin Ni / Chengyao Zheng / Man Hua

Geoscience Letters, Vol 4, Iss 1, Pp 1-

2017 Volume 11

Abstract: Abstract As an important plasma wave mode in the geospace, magnetosonic waves can interact with both radiation belt electrons and protons, thereby impacting the dynamics of magnetospheric particles. Based on the Doppler-shifted resonance condition and ... ...

Abstract	Abstract As an important plasma wave mode in the geospace, magnetosonic waves can interact with both radiation belt electrons and protons, thereby impacting the dynamics of magnetospheric particles. Based on the Doppler-shifted resonance condition and the cold plasma dispersion relation, we investigate the profiles of resonance zone and resonant frequency of the Landau resonance between radiation belt electrons and magnetosonic waves and the cyclotron resonances with protons. The results demonstrate that resonant interactions between magnetosonic waves and magnetospheric charged particles largely rely on L-shell, wave normal angle, and kinetic energy and equatorial pitch angle of particles. Resonance zones for the Landau resonance between magnetosonic waves and radiation belt electrons are confined to a very narrow (mostly less than 1°) extent of magnetic latitude, which tends to shift to lower latitudes with increasing equatorial pitch angle and decreasing electron energy. Landau resonance frequencies also increase with magnetosonic wave normal angle. In contrast, higher order cyclotron resonances of magnetosonic waves with protons are much easier to occur in a broad range of magnetic latitude. As the resonance order increases, the coverage of the resonance zone shrinks overall and occupies the geomagnetic equatorial region. In addition, resonant frequencies increase with resonance order. Corresponding to higher order cyclotron resonances, protons are more likely to interact with magnetosonic waves at intermediate to high frequencies. Our study can be useful to elaborate the resonant interaction processes between magnetosonic waves and radiation belt electrons and protons and improve the current understanding of the multi-aspect impact of magnetosonic waves on the magnetospheric particle dynamics.
Keywords	Magnetosonic waves ; Radiation belts ; Wave–particle interactions ; Resonance zone and resonant frequency ; Science ; Q ; Geology ; QE1-996.5
Subject code	535
Language	English
Publishing date	2017-09-01T00:00:00Z
Publisher	SpringerOpen
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article ; Online: Very-Low-Frequency transmitters bifurcate energetic electron belt in near-earth space

Man Hua / Wen Li / Binbin Ni / Qianli Ma / Alex Green / Xiaochen Shen / Seth G. Claudepierre / Jacob Bortnik / Xudong Gu / Song Fu / Zheng Xiang / Geoffrey D. Reeves

Nature Communications, Vol 11, Iss 1, Pp 1-

2020 Volume 9

Abstract: Very-Low-Frequency (VLF) communication transmitters, operate worldwide, radiate emissions at particular frequencies 10-30 kHz. Here, the authors show VLF transmitter emissions that leak from the Earth’s ground are primarily responsible for bifurcating ... ...

Abstract	Very-Low-Frequency (VLF) communication transmitters, operate worldwide, radiate emissions at particular frequencies 10-30 kHz. Here, the authors show VLF transmitter emissions that leak from the Earth’s ground are primarily responsible for bifurcating the energetic electron belt over 20–100 keV.
Keywords	Science ; Q
Language	English
Publishing date	2020-09-01T00:00:00Z
Publisher	Nature Portfolio
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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