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Designing shielded radio-frequency phased-array coils for magnetic resonance imaging

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Chinese Physics B 2013年第1期22卷 46-53页

作者：徐文龙张鞠成李霞徐冰俏陶贵生 department of biomedical Engineering China Jiliang University department of biomedical Engineering Zhejiang University

In this paper, an approach to the design of shielded radio-frequency （RF） phased-array coils for magnetic resonance imaging （MRI） is proposed. The target field method is used to find current densities distributed on primary and shield coils. The stream function technique is used to discretize current densities and to obtain the winding patterns of the coils. The corresponding highly ill-conditioned integral equation is solved by the Tikhonov regularization with a penalty function related to the minimum curvature. To balance the simplicity and smoothness with the homogeneity of the magnetic field of the coll＇s winding pattern, the selection of a penalty factor is discussed in detail.

关键词： active shield phased-array coil radio-frequency coil magnetic resonance imaging

The financial burden of physical inactivity

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Journal of Sport and Health Science 2014年第1期3卷 58-59页

作者： Li Li department of Health and kinesiology Georgia Southern University

According to the World Health Organization,"physical inactivity has been identified as the fourth leading risk factor for global mortality causing an estimated 3.2 million (annual)deaths globally.”1In the Research Highlight of the first issue of this journal,I reviewed the evidence which supports the notion that physical inactivity can cost lives,in terms of longevity and quality of life,especially in the last few years of our lives.2 Here,I would like to review the literature that reveals the financial burden due to physical inactivity.

关键词： The financial burden of physical inactivity

Regulation of sleep by astrocytes in the hypothalamic ventrolateral preoptic nucleus

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Neural Regeneration Research 2025年第4期20卷 1098-1100页

作者： Jae-Hong Kim Ruqayya Afridi Il-Sung Jang Maan Gee Lee Kyoungho Suk Brain Korea 21 four KNU Convergence Educational Program of biomedical Sciences for Creative Future Talents School of MedicineKyungpook National UniversityDaeguRepublic of Korea department of Pharmacology School of MedicineKyungpook National UniversityDaeguRepublic of Korea department of Pharmacology School of DentistryKyungpook National UniversityDaeguRepublic of Korea Brain Science&Engineering Institute Kyungpook National UniversityDaeguRepublic of Korea

Astrocytes are functionally dynamic cells that support neurons in multiple ways throughout an organism’s *** astrocytic regulation of neuronal activity has been increasingly recognized in recent *** are now recognized as playing a more complex role than mere bystanders in the central nervous ***,their role in regulating the sleep neurocircuitry is not well *** this perspective,we highlight the role of astrocytes in sleep modulation,with a particular focus on regulatory mechanisms related to the ventrolateral preoptic nucleus(VLPO)of the *** briefly discuss recent literature reporting the role of VLPO astrocytes in regulating sleep-associated behaviors.

关键词： sleep ventrolateral astrocytes

Differences between lower extremity joint running kinetics captured by marker-based and markerless systems were speed dependent

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Journal of Sport and Health Science 2024年第4期13卷 569-578页

作者： Hui Tang Barry Munkasy Li Li department of Health Sciences and kinesiology Georgia Southern UniversityStatesboroGA 30458USA department of kinesiology and Health Education University of Texas at AustinAustinTX 78712USA

Background:The development of computer vision technology has enabled the use of markerless movement tracking for biomechanical *** research has reported the feasibility of markerless systems in motion analysis but has yet to fully explore their utility for capturing faster movements,such as *** studies using markerless systems in clinical and sports settings are still ***,the present study compared running biomechanics estimated by marker-based and markerless *** running speed not only affects sports performance but is also associated with clinical injury prevention,diagnosis,and rehabilitation,we aimed to investigate the effects of speed on the comparison of estimated lower extremity joint moments and powers between markerless and marker-based technologies during treadmill running as a concurrent validating ***:Kinematic data from marker-based/markerless technologies were collected,along with ground reaction force data,from 16 young adults running on an instrumented treadmill at 3 speeds:2.24 m/s,2.91 m/s,and 3.58 m/s(5.0 miles/h,6.5 miles/h,and 8.0 miles/h).Sagittal plane moments and powers of the hip,knee,and ankle were calculated by inverse dynamic *** series analysis and statistical parametric mapping were used to determine system ***:Compared to the marker-based system,the markerless system estimated increased lower extremity joint kinetics with faster speed during the swing phase in most ***:Despite the promising application of markerless technology in clinical settings,systematic markerless overestimation requires focused *** on segment pose estimations,the centers of mass estimated by markerless technologies were farther away from the relevant distal joint centers,which led to greater joint moments and powers estimates by markerless ***-based *** differences were amplified by running speed.

关键词： Biomechanics Motion capture Gait Statistical parametric mapping

Is changing footstrike pattern beneficial to runners?

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Journal of Sport and Health Science 2017年第2期6卷 146-153页

作者： Joseph Hamill Allison H.Gruber Biomechanics Laboratory Department of KinesiologyUniversity of MassachusettsAmherstMA 01003USA Biomechanics Laboratory Department of KinesiologyIndiana UniversityBloomingtonIN 47405USA

Some researchers, running instructors, and coaches have suggested that the "optimal" footstrike pattern to improve performance and reduce running injuries is to land using a mid-or forefoot strike. Thus, it has been recommended that runners who use a rearfoot strike would benefit by changing their footstrike although there is little scientific evidence for suggesting such a change. The rearfoot strike is clearly more prevalent. The major reasons often given for changing to a mid-or forefoot strike are(1) it is more economical;(2) there is a reduction in the impact peak and loading rate of the vertical component of the ground reaction force; and(3) there is a reduction in the risk of a running-related injuries. In this paper,we critique these 3 suggestions and provide alternate explanations that may provide contradictory evidence for altering one's footstrike *** have concluded, based on examining the research literature, that changing to a mid-or forefoot strike does not improve running economy, does not eliminate an impact at the foot-ground contact, and does not reduce the risk of running-related injuries.

关键词： Epidemiology Footfall patterns Forefoot Ground reaction force Impacts Midfoot Rearfoot Running economy

浅陷阱态调控增强绿色发光钙钛矿微球的负热猝灭效应（英文）

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Science China Materials 2025年第1期 149-155页

作者：林圳旭黄锐宋捷张毅林泽文李洪亮吴海霞侯得健郭艳青王静朱剑豪 School of Materials Science and Engineering Hanshan Normal University Ministry of Education Key Laboratory of Bioinorganic and Synthetic Chemistry State Key Laboratory of Optoelectronic Materials and Technologies Sun YatSen University department of Physics Department of Materials Science and Engineering and Department of Biomedical Engineering City University of Hong Kong

发光材料中的负热猝灭（NTQ）现象,表现为随温度升高发光强度增加,在照明和显示技术中具有广泛应用前景.然而,在金属卤化物钙钛矿中实现NTQ具有一定挑战性,其机制尚不完全清楚.本研究通过低温光致发光、长余辉和热释光谱技术,系统研究了...

发光材料中的负热猝灭（NTQ）现象,表现为随温度升高发光强度增加,在照明和显示技术中具有广泛应用前景.然而,在金属卤化物钙钛矿中实现NTQ具有一定挑战性,其机制尚不完全清楚.本研究通过低温光致发光、长余辉和热释光谱技术,系统研究了CsPbBr3微球中NTQ现象的起源.结果表明, NTQ现象与浅陷阱态中载流子的释放密切相关.实验与理论分析揭示,这些浅缺陷态的能级位于导带下方约0.135 eV处.快速热处理可显著增加浅陷阱的密度,从而增强NTQ效应,使室温下的光致发光强度较150 K时提高了60%以上.同时,该处理将受激自发辐射的阈值降低至约45 W/cm2.本研究不仅加深了对CsPbBr3微球中NTQ机制的理解,也为通过能态调控提升钙钛矿光电子器件性能开辟了新途径.

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Measurement invariance and latent mean differences of the Chinese version physical activity self-efficacy scale across gender and education levels

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Journal of Sport and Health Science 2019年第1期8卷 46-54页

作者： Han Chen Jun Dai Yong Gao department of kinesiology and Physical Education Valdosta State University School of Sport Leisure Recreation and Arts Shanghai University of Sport department of kinesiology Boise State University

Background: Self-efficacy has been identified as an important determinant of youth's behavior change including physical activity(PA) participation. However, the dimensionality check of a PA self-efficacy scale has rarely been conducted in China. The current study aims to examine(1) the unidimensionality of a shortened Chinese version of PA self-efficacy scale(S-PASESC);(2) the measurement invariance of S-PASESC across gender and levels of education;(3) the latent factor mean difference between gender and levels of education;(4) the direct effects of self-efficacy on PA by different gender and education levels; and(5) the comparisons of the direct effects of self-efficacy on PA across gender and education ***: The participants were 5 th through 11 th grade public school students recruited from 7 cities located in different geographic regions of China. The final data include a total of 3003 participants(49.7% boys) who have completed the ***: Confirmatory factor analysis(CFA) test supported the unidimensionality of S-PASESC. The S-PASESC is invariant across gender and 3 levels of education at both configural, full metric, and full scalar levels. Findings from latent mean comparisons showed that boys reported higher PA self-efficacy than girls. Students' perceived PA self-efficacy tend to decrease from elementary to high school. Finally, self-efficacy positively related to PA by groups of different gender and education levels and the relationship between self-efficacy and PA is stronger among middle school boys than ***: Findings suggest S-PASESC is a valid scale for measuring Chinese students' PA self-efficacy.

关键词： Chinese adolescents Education levels Factor analysis Gender Latent mean comparison Measurement invariance Physical activity self-efficacy scale

The contribution of small and large sensory afferents to postural control in patients with peripheral neuropathy

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Journal of Sport and Health Science 2019年第3期8卷 218-227页

作者： Li Li Shuqi Zhang John Dobson College of Physical Education Hunan Normal University department of Health Sciences and kinesiology Georgia Southern University department of kinesiology and Physical Education Northern Illinois University

Peripheral neuropathy(PN) is a multifarious disorder that is caused by damage to the peripheral nerves. Although the symptoms of PN vary with the etiology, most cases are characterized by impaired tactile and proprioceptive sensation that progresses in a distal to proximal manner. Balance also tends to deteriorate as the disorder becomes more severe, and those afflicted are substantially more likely to fall while walking compared with those who are healthy. Most patients with PN walk more cautiously and with greater stride variability than age-matched controls, but the majority of their falls occur when they must react to a perturbation such as a slippery or uneven surface. The purpose of this study was to first describe the role of somatosensory feedback in the control of posture and then discuss how that relationship is typically affected by the most common types of PN. A comprehensive review of the scientific literature was conducted using MEDLINE, and the relevant information was synthesized. The evidence indicates that the proprioceptive feedback that is conveyed primarily through larger type I afferents is important for postural control. However, the evidence indicates that the tactile feedback communicated through smaller type II afferents is particularly critical to the maintenance of balance. Many forms of PN often lead to chronic tactile desensitization in the soles of the feet and, although the central nervous system seems to adapt to this smaller type II afferent dysfunction by relying on more larger type I afferent reflex loops, the result is still decreased stability. We propose a model that is intended both to help explain the relationship between stability and the smaller type II afferent and the larger type I afferent feedback that may be impaired by PN and to assist in the development of pertinent rehabilitative interventions.

关键词： Balance Biomechanics Neuroplasticity Peripheral neuropathy Postural control Rehabilitation

The impact of perceived social support, loneliness, and physical activity on quality of life in South Korean older adults

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Journal of Sport and Health Science 2018年第2期7卷 237-244页

作者： Hyun-Wook Kang Meungguk Park Juliane Poock Wallace (Hernandez) department of Recreational Sports Dankook University department of kinesiology Southern Illinois University

Purpose: The purpose of this study was to propose and test a conceptual model that explains the interrelationships among perceived social support, loneliness, physical activity(PA), and quality of life(QoL) among active older adults in South ***: Data were collected from 332 individuals over the age of 65 using a systematic stratified convenience sampling method. Survey data were collected and analyzed using a structural equation model(SEM).Results: Perceived social support had a significantly positive effect on PA(b = 0.14, p < 0.01) and QoL(b = 0.28, p < 0.001) while decreasing loneliness(b = —0.55, p < 0.001). PA had a significant positive effect on QoL(b = 0.12, p < 0.01), and loneliness had a negative effect on QoL(b = —0.37, p < 0.001). Loneliness mediated the relationship between perceived social support and ***: The SEM results of the current study support the proposed model that explained the interrelationships among perceived social support, loneliness, PA, and QoL among active older adults in South Korea. These findings suggest the importance of incorporating social support mechanisms for PA interventions in order to enhance QoL. The findings of this study can help create more effective health and physical education programs for the older generations in South Korea to enhance their QoL.

关键词： Loneliness Perceived social support Physical activity Quality of life South Korean older adults Structural equation modeling