EMG-Based Continuous and Simultaneous Estimation of Arm Kinematics in Able-Bodied Individuals and Stroke Survivors

Liu, Jie,Kang, Sang Hoon,Xu, Dali,Ren, Yupeng,Lee, Song Joo,Zhang, Li-Qun Frontiers Media S.A. 2017 Frontiers in neuroscience Vol.11 No.-

<P>Among the potential biological signals for human-machine interactions (brain, nerve, and muscle signals), electromyography (EMG) widely used in clinical setting can be obtained non-invasively as motor commands to control movements. The aim of this study was to develop a model for continuous and simultaneous decoding of multi-joint dynamic arm movements based on multi-channel surface EMG signals crossing the joints, leading to application of myoelectrically controlled exoskeleton robots for upper-limb rehabilitation. Twenty subjects were recruited for this study including 10 stroke subjects and 10 able-bodied subjects. The subjects performed free arm reaching movements in the horizontal plane with an exoskeleton robot. The shoulder, elbow and wrist movements and surface EMG signals from six muscles crossing the three joints were recorded. A non-linear autoregressive exogenous (NARX) model was developed to continuously decode the shoulder, elbow and wrist movements based solely on the EMG signals. The shoulder, elbow and wrist movements were decoded accurately based only on the EMG inputs in all the subjects, with the variance accounted for (VAF) > 98% for all three joints. The proposed approach is capable of simultaneously and continuously decoding multi-joint movements of the human arm by taking into account the non-linear mappings between the muscle EMGs and joint movements, which may provide less effortful control of robotic exoskeletons for rehabilitation training of individuals with neurological disorders and arm impairment.</P>

Ginseng-derived nanoparticles induce skin cell proliferation and promote wound healing

Song Yang,Shuyan Lu,Limei Ren,Shuai Bian,Daqing Zhao,Meichen Liu,Jiawen Wang 고려인삼학회 2023 Journal of Ginseng Research Vol.47 No.1

Orthogonal lipid sensors identify transbilayer asymmetry of plasma membrane cholesterol

Liu, Shu-Lin,Sheng, Ren,Jung, Jae Hun,Wang, Li,Stec, Ewa,O'Connor, Matthew J,Song, Seohyoen,Bikkavilli, Rama Kamesh,Winn, Robert A,Lee, Daesung,Baek, Kwanghee,Ueda, Kazumitsu,Levitan, Irena,Kim, Kwang NATURE PUBLISHING GROUP 2017 NATURE CHEMICAL BIOLOGY Vol. No.

<P>Controlled distribution of lipids across various cell membranes is crucial for cell homeostasis and regulation. We developed an imaging method that allows simultaneous in situ quantification of cholesterol in two leaflets of the plasma membrane (PM) using tunable orthogonal cholesterol sensors. Our imaging revealed marked transbilayer asymmetry of PM cholesterol (TAPMC) in various mammalian cells, with the concentration in the inner leaflet (IPM) being -12-fold lower than that in the outer leaflet (OPM). The asymmetry was maintained by active transport of cholesterol from IPM to OPM and its chemical retention at OPM. Furthermore, the increase in the IPM cholesterol level was triggered in a stimulus-specific manner, allowing cholesterol to serve as a signaling lipid. We found excellent correlation between the IPM cholesterol level and cellular Wnt signaling activity, suggesting that TAPMC and stimulus-induced PM cholesterol redistribution are crucial for tight regulation of cellular processes under physiological conditions.</P>

Estimating the Effects of Corrosion Pitting Morphology on Residual Fatigue Properties of Corroded Steel Based on Fractal Theory

Ren Songbo,Gu Ying,Gao Xinqiang,Gu Song,Kong Chao,Zeng Shenghui,Liu Peng,Li Xiaoge 한국강구조학회 2023 International Journal of Steel Structures Vol.23 No.2

In order to discuss the effect of corrosion results on fatigue properties of corroded steel, the morphology measurements and fatigue tests were performed to 10 corroded steel specimens obtained by artificial accelerated corrosion tests. And the corroded morphological characteristics and fatigue fracture of corroded specimen were studied. The results found the fracture mode and fatigue life were closely associated with the corroded morphological characteristics, especially for the fracturing source corrosion pit (FC-corrosion pit). So, based on the systematically analysis, the fatigue life prediction method of corroded steel was proposed.

Crushing study for interlocked armor layers of unbonded flexible risers with a modified equivalent stiffness method

Ren, Shaofei,Liu, Wencheng,Song, Ying,Geng, Hang,Wu, Fangguang The Society of Naval Architects of Korea 2019 International Journal of Naval Architecture and Oc Vol.11 No.1

Interlocked armor layers of unbonded flexible risers may crush when risers are being launched. In order to predict the behavior of interlocked armor layers, they are usually simplified as rings with geometric and contact nonlinearity ignored in the open-literature. However, the equivalent thickness of the interlocked armor layer has not been addressed yet. In the present paper, a geometric coefficient ${\gamma}$ is introduced to the equivalent stiffness method, and a linear relationship between ${\gamma}$ and geometric parameters of interlocked armor layers is validated by analytical and finite element models. Radial stiffness and equivalent thickness of interlocked armor layers are compared with experiments and different equivalent methods, which show that the present method has a higher accuracy. Furthermore, hoop stress distribution of interlocked armor layer under crushing is predicted, which indicates the interlocked armor layer can be divided into two compression and two expansion zones by four symmetrically distributed singular points.

Ground Motion Frequency Insensitivity of Bearing-Supported Pedestrian Bridge with Viscous Dampers

Qunfeng Liu,Shimin Zhu,Wenshan Yu,Xing Wu,Fei Song,Xiang Ren 대한토목학회 2021 KSCE JOURNAL OF CIVIL ENGINEERING Vol.25 No.7

This work studies the dynamic responses of bearing-supported pedestrian bridges with Y-shaped piers and various deck widths under harmonic ground motions. To fulfill the immediate occupancy performance objective, the dynamic responses of bridges with linear or nonlinear viscous dampers are evaluated by performing nonlinear time-history analyses. The results show that the maximum transverse displacements of girder and pier top in original bridges are closely dependent on the characteristic period of ground motion. The installation of linear viscous dampers between steel girder and Y-shaped piers can effectively improve the seismic performance of bridges and hence reduce the corresponding shear demand of bearings. Further parametric studies show that, with optimal damping coefficient and velocity exponent, the seismic performances of bridges with viscous dampers can be insensitive to the characteristic period of ground motion.

3D Printing of Bioinspired Structural Materials with Fibers Induced by Doctor Blading Process

Luquan Ren,Bingqian Li,Zhengyi Song,Qingping Liu,Lei Ren,Xueli Zhou 한국정밀공학회 2019 International Journal of Precision Engineering and Vol.6 No.1

Fiber is a crucial element in biological micro-structural materials. Replication of fiber-reinforced composites with analogous architectures of their natural counterparts has caused widespread academic concern. Recent researches indicate 3D printing technology has the potential to produce biomimetic structural materials. The aim of this study is to develop a process to fabricate fiber-reinforced composites with ordered yet spatially tunable fiber arrangement. Specifically, we present a method to align fibers during the 3D printing of fiber-reinforced composites. A modified slurry-based stereolithography process was developed, and the fibers in the fiber–resin mixture were aligned by Shear force produced during the spreading of slurry. We investigated the influence of relative factors on fiber orientation, and two models were used to uncover the internal mechanism. By controlling the speed and the direction of the moving blade, the patterns that fibers were arranged can be freely programmed. Therefore, we have extracted bioinspired sinusoidal and zigzag design motifs to analyze their mechanical properties compared with non-bioinspired motifs. The proposed method is relatively material agnostic, more efficient and more facile. It thus provides a promising route to fabricate fiber-reinforced composites, and has potential to be adopted in biological structures researches and industrial applications.

Fluorinated/Non-Fluorinated Sulfonated Polynaphthalimides as Proton Exchange Membranes

Yang Song,Chang Liu,Dianfu Ren,Liwei Jing,Zhenhua Jiang,Baijun Liu 한국고분자학회 2013 Macromolecular Research Vol.21 No.5

Two -SO3H containing diamine monomers, 2,5-bis(4-amino-2-trifluoromethylphenoxy)benzenesulfonic acid and 2,5-bis(4-aminophenoxy)benzenesulfonic acid were successfully synthesized through a typical aromatic nucleophilic substitution reaction followed by a reduction reaction, respectively. Derived from the diamine monomers,two series of sulfonated naphthalic polyimides (polynaphthalimides) containing ether and ketone linkages were synthesized through a “one pot” polymerization reaction. Some properties including thermal stability, mechanical properties, water uptake, swelling dimensional ratio, methanol permeability, and proton conductivity were thoroughly investigated. Some exhibited attractive properties as proton exchange membranes. It was found that the fluorinated series (CF3-SPI-X) exhibited higher dimensional stability and lower methanol permeability in comparison with non-fluorinated ones (SPI-X) at the same -SO3H group content.

Crushing study for interlocked armor layers of unbonded flexible risers with a modified equivalent stiffness method

Shaofei Ren,Wencheng Liu,Ying Song,Hang Geng,Fangguang Wu 대한조선학회 2019 International Journal of Naval Architecture and Oc Vol.11 No.1

Interlocked armor layers of unbonded flexible risers may crush when risers are being launched. In order to predict the behavior of interlocked armor layers, they are usually simplified as rings with geometric and contact nonlinearity ignored in the open-literature. However, the equivalent thickness of the interlocked armor layer has not been addressed yet. In the present paper, a geometric coefficient g is introduced to the equivalent stiffness method, and a linear relationship between g and geometric parameters of interlocked armor layers is validated by analytical and finite element models. Radial stiffness and equivalent thickness of interlocked armor layers are compared with experiments and different equivalent methods, which show that the present method has a higher accuracy. Furthermore, hoop stress distribution of interlocked armor layer under crushing is predicted, which indicates the interlocked armor layer can be divided into two compression and two expansion zones by four symmetrically distributed singular points.

Effect of golden needle mushroom (Flammulina velutipes) stem waste on laying performance, calcium utilization, immune response and serum immunity at early phase of production

Mahfuz, Shad,Song, Hui,Liu, Zhongjun,Liu, Xinyu,Diao, Zipeng,Ren, Guihong,Guo, Zhixin,Cui, Yan Asian Australasian Association of Animal Productio 2018 Animal Bioscience Vol.31 No.5

Objective: This experiment was conducted to evaluate the effects of golden needle mushroom (Flammulina velutipes) stem waste (FVW), on organic eggs production, calcium utilization, antibody response, serum immunoglobulin, and serum cytokine concentration at early phase of production in laying hens. Methods: A total 210, 19 weeks old aged ISA Brown layers were randomly assigned into 5 equal treatment groups, with 7 replications of 6 hens each. Dietary treatment included a standard basal diet as control; antibiotic (0.05% flavomycin); 2% FVW; 4% FVW; and 6% FVW. The experimental duration was 10 weeks. Results: There was no significant differences (p>0.05) on hen day egg production, egg weight, egg mass, feed intake, and feed conversion ratio (FCR) among experimental groups. Unmarketable eggs were significantly lower (p<0.05) both in 4% FVW and 6% FVW fed groups than control group. The calcium retention and calcium in egg shell deposition were significantly higher (p<0.05) in FVW inclusion groups than control and antibiotic groups. Antibody titers against Newcastle diseases were significantly higher (p<0.05) in 6% FVW fed group (except combined with 4% FVW at day 147) and infectious bronchitis were significantly higher (p<0.05) in FVW fed groups (except 2% FVW and 4% FVW at day 161) than control and antibiotic groups. Serum immunoglobulin sIgA was significantly higher (p<0.05) in all levels of FVW and IgG was significantly higher (p<0.05) in 4% FVW than control and antibiotic groups. Serum cytokine concentration interleukin-2 (IL-2) was significantly higher (p<0.05) in 6% FVW; IL-6 and tumor necrotic $factor-{\alpha}$ were significantly higher (p<0.05) both in 4% FVW and 6% FVW than control and antibiotic groups; IL-4 was significantly higher (p<0.05) in antibiotic, 2% FVW and 4% FVW fed groups than control. Conclusion: F. velutipes mushroom waste can be used as a novel substitute for antibiotic for organic egg production and sound health status in laying hens.