The Effect of Stretching the Clavicular Fibers of the Pectoralis Major Muscle on Thoracic Kyphosis Angle

Liu Yaoyao,Sang-Woo Kim,Yu-Jeong Yun,Ye-Won Lee,Hye-In Lee,Jae-Won Huh,Won-Gyu Yoo 한국임상움직임치료학회 2021 한국임상움직임치료학회지 Vol.1 No.2

Background : In modern society, many people spend considerable time using visual display terminals, which can accelerate the induction of thoracic kyphosis. The abnormal arrangement of the thoracic vertebrae causes shortening of the pectoralis major muscle, in order to alleviate the thoracic spine lesions, stretching movements in the thoracic spine and thorax can relieve the tension in the intervertebral discs and surrounding tissues between the vertebrae and improve the thoracic kyphosis posture. Objectives : Three kinds of pectoralis major muscle extension training were designed to explore the effect of pectoralis major muscle extension on the angle of thoracic kyphosis, so as to provide theoretical guidance and data support for the clinical treatment and prevention of thoracic kyphosis. Methods : Ten adults with normal thoracic curvature were included in this study. Three methods 1) self-stretching on wall corner, 2) self-stretching with foam roller, 3) stretching in standing posture were applied for 5 days to stretch the pectoralis major. A double inclinometer was placed on the spinous process of the 1st and 12th thoracic vertebrae before and after the experiment, to measure changes in the thoracic kyphosis angle and compare the differences between the anterior and posterior data. Results : The thoracic kyphosis angle after extension exercise of the pectoralis major muscle was 24.9 ±6.78, while the thoracic kyphosis angle calculated before extension exercise was 27.4 ± 7.59, and there was a significant difference between the two p < 0.05. Conclusions : This study suggests that stretching the clavicular fibers of the pectoralis major muscle helps to reduce thoracic kyphosis.

Comparative Analysis of the Electromyography Activity of Core Muscles During Balance Pad- and Sling-assisted Exercises

Yaoyao Liu,Won-gyu Yoo,Su-Jung Kim 한국전문물리치료학회 2020 한국전문물리치료학회지 Vol.27 No.4

Background: Unstable surface-based core training can significantly enhance core strength, but no studies have compared the effects of balance pad- and sling-assisted exercises. Objects: To study the effects of unstable surface-based balance pad- and sling-assisted core strength exercises on muscle activity. Methods: Twenty male students aged 20–25 years participated in this study. The effects of three types of core strength exercises, performed with a sling or balance pad, on the activities of three muscles, i.e., the right musculus obliquus externus abdominis (EO), right erector spinae (ES), and right gluteus maximus (GM), were examined. Results: 1) In the glute bridge exercise, the percentage of maximum voluntary contraction of the EO, ES, and GM were significantly different between the balance pad- and sling-assisted exercises. The relative contribution of the ES and GM activities to all muscle activity were not significantly different between the two training types, whereas that for EO showed a significant difference. 2) There was no significant difference in the percentage value of maximum voluntary contraction (%MVC) among the EO, ES, and GM during the “leg-lifting with flat support”exercise, and there were no significant difference in the relative contributions between the two training types. 3) In the “side bridge leg separation exercise”, the %MVC of the ES, EO, and GM were significantly different between the two training types. Conclusion: Sling training for core muscles was generally better than balance pad assist training. The majority of physiotherapy patients require core training. Our results could guide physiotherapists in the choice of targeted exercises for these patients.

Ganoderic acid A attenuates high‑fat‑diet‑induced liver injury in rats by regulating the lipid oxidation and liver inflammation

Fuli Liu,Kejian Shi,Jiaojiao Dong,Zhousheng Jin,Yiquan Wu,Yaoyao Cai,Tingting Lin,Qianqian Cai,Le Liu,Yujian Zhang 대한약학회 2020 Archives of Pharmacal Research Vol.43 No.7

Ganoderic Acid A (GA) has many pharmacologicaleffects such as anti-tumor, antibacterial, anti-inflammatory,and immunosuppressive effects. However, the protectiveeffect of GA on liver injury has not been reported. Thisstudy aimed to investigate the action of GA on insufficientmethionine and choline combined with high-fat diet (HFD)-induced non-alcoholic fatty liver disease (NAFLD) in rats. NAFLD model was established by insufficient methionineand choline combined with high fat feeding to rats. The levelsof Acetyl-CoA carboxylase, fatty acid synthase, sterolregulatory element binding protein, liver X receptors, AMPactivatedprotein kinase, peroxisome proliferator-activatedreceptor α, PPARg coactivator 1α and NF-κB pathway inthe liver were detected by western blot. The results of thisstudy demonstrated that the expression of GA can not onlysignificantly decrease the live weight and liver weight perbody weight of HFD mice, but also restore the alanine aminotransferase,aspartate aminotransferase, total bilirubinlevels, triglyceride and cholesterol in serum. In addition,the expression of GA increased the levels of high-densitylipoprotein cholesterol in serum, ameliorated pathologicalchanges and decreased NAS score of mice’s liver. In conclusion,the treatment with GA could improve NAFLD in ratsby regulating the levels of signaling events involved in freefatty acid production, lipid oxidation and liver inflammation.

A heterogeneous lattice structure modeling technique supported by multiquadric radial basis function networks

Liu Yuan,Yang Huiyuan,Zhao Yaoyao Fiona,Zheng Guolei 한국CDE학회 2022 Journal of computational design and engineering Vol.9 No.1

With the rapid advancement of the multimaterial additive manufacturing (AM) technology, the heterogeneous lattice structures (HLSs) comprising the multiphase materials with gradual variations have become feasible and accessible to the industry. However, the multimaterial AM capabilities have far outpaced the modeling capability of design systems to model and thus design novel HLSs. To further expand the design space for the utilization of AM technology, this paper proposes a method for modeling HLS with complex geometries and smooth material transitions. The geometric modeling and material modeling problems are formulated in a rigorous and computationally effective manner. The geometric complexity of HLS is significantly reduced by a semi-analytical unit cell decomposition strategy that is applied to split HLS into material units: struts and connectors. The smooth material transitions of the connector associated with multimaterial struts are realized by interpolating the discrete material property values defined at control points using a multiquadric radial basis function network.

대학 스포츠 선수의 감성지능, LMX, TMX 및 선수만족의 구조적 관계

( Liu Menglei ),( Yaoyao ),조성균 대한무도학회 2022 대한무도학회 학술대회자료집 Vol.2022 No.2

A New Model-free Robust Adaptive Control of Cable-driven Robots

Yaoyao Wang,Lufang Liu,Mingxing Yuan,Qingxun Di,Bai Chen,Hongtao Wu 제어·로봇·시스템학회 2021 International Journal of Control, Automation, and Vol.19 No.9

For high performance control of cable-driven robots, a new model-free robust adaptive control is proposed using adaptive proportional-integral-derivative nonsingular fast terminal sliding mode (PID-NFTSM) in this paper. The designed control scheme has three elements, which are time-delay estimation (TDE) and a new PIDNFTSM manifold and a combined adaptive reaching law. The TDE element is applied to achieve the lumped system dynamics and hence founds a practical model-free structure. Meanwhile, a new PID-NFTSM manifold is designed to inherit the advantages of the NFTSM and high-order SM (HOSM) and integral SM (ISM) controls. Because of this design, the PID-NFTSM manifold can effectively ensure the non-singularity and high comprehensive control performance. Then, by combining the fast-TSM-type reaching law and a constant speed one with adaptive gain, we design a new combined adaptive reaching law for performance reinforcement. Benefiting from above three parts, our proposed control is model-free, highly precise and strongly robust. Stability is analyzed using Lyapunov theory. The effectiveness of our control is proved by comparative simulation studies. For high performance control of cable-driven robots, a new model-free robust adaptive control is proposed using adaptive proportional-integral-derivative nonsingular fast terminal sliding mode (PID-NFTSM) in this paper. The designed control scheme has three elements, which are time-delay estimation (TDE) and a new PIDNFTSM manifold and a combined adaptive reaching law. The TDE element is applied to achieve the lumped system dynamics and hence founds a practical model-free structure. Meanwhile, a new PID-NFTSM manifold is designed to inherit the advantages of the NFTSM and high-order SM (HOSM) and integral SM (ISM) controls. Because of this design, the PID-NFTSM manifold can effectively ensure the non-singularity and high comprehensive control performance. Then, by combining the fast-TSM-type reaching law and a constant speed one with adaptive gain, we design a new combined adaptive reaching law for performance reinforcement. Benefiting from above three parts, our proposed control is model-free, highly precise and strongly robust. Stability is analyzed using Lyapunov theory. The effectiveness of our control is proved by comparative simulation studies.

Polishing surface integrity of TC17 aeroengine blades

De Liu,Yaoyao Shi,Xiaojun Lin,Chao Xian,Zhiyang Gu 대한기계학회 2020 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.34 No.2

Aeroengine blades have high requirements for surface integrity. Through the flexible polishing of TC17 engine blades, the surface integrity of polished blades is improved. First, the influence of process parameters on polishing force and polishing temperature is analyzed through experiments. The influence of parameters on surface roughness is analyzed, and the relationship between wear debris shape and surface morphology under different process parameters are analyzed from the microscopic level. Second, the influence of process parameters on the residual stress of the polished surface is analyzed in accordance with the polishing force and polishing temperature. Then, the variation of the residual stress of the blade after milling and polishing is analyzed. In addition, the microstructure of the metamorphic layer after milling and polishing is analyzed. Experimental results show that reasonable polishing parameters can effectively improve the surface integrity of the blade.

Study on Mechanical Properties and Fracture Behavior of Granite after Thermal Treatment under Brazilian Splitting Test

Hanxiang Liu,Hongwen Jing,Qian Yin,Zhenlong Zhao,Yaoyao Meng,Liang Zhang 대한토목학회 2023 KSCE JOURNAL OF CIVIL ENGINEERING Vol.27 No.2

In this paper, the effects of thermal treatment on the mechanical properties, fracturecharacteristics, and roughness of the fracture surface of granite under the Brazilian splitting testare studied using an electro-hydraulic servo testing machine with an acoustic emission (AE)and digital image correlation (DIC) system. The test results show that: 1) Thermal treatmentdegrades the physical and mechanical properties. Density, P-wave velocity, and peak load ofgranite decrease with the increase in thermal treatment temperature (T). 2) With the increasing T,the fracture pattern changes from “I” type tensile fractures to “Y” type tensile-shear mixedfailure. The DIC results show that the fracture process changes from transient to progressive. 3) AE counts show that granite gradually changes from brittleness to ductility with the increaseof T. Furthermore, the variations in the RA and AF values of the AE events indicate that theincreasing T leads to an increase in shear cracks in granite. After the test, 4) the roughness ofthe fracture surface of the specimen was analyzed using a spatial digitizer. The results showthat thermal treatment significantly improved the fracture surface's asperity height androughness. 5) Scanning electron microscopy (SEM) results revealed that thermal treatmentleads to the generation of micro-cracks in granite and the desquamation of mineral grains,which influences the macro properties of granite.

Synthesis of the crystalline porous copper oxide architectures derived from metal-organic framework for electrocatalytic oxidation and sensitive detection of glucose

Lili Li,Yaoyao Liu,Lunhong Ai,Jing Jiang 한국공업화학회 2019 Journal of Industrial and Engineering Chemistry Vol.70 No.-

The porous CuO architectures have been successfully synthesize by the effective transformation of aCu-BTC metal-organic frameworks (MOFs) through a facile heating treatment. The as-synthesized porousCuO architectures exhibit high electrocatalytic activity toward the glucose oxidation. When evaluated asa nonenzymatic glucose biosensor, the porous CuO architectures manifest fast response within 1.3 s, widelinear range from 0.5 mM to 2.8 mM, low detection limit of 0.1 mM (signal-to-noise ratio of 3), highsensitivity up to 934.2 mA mM 1cm 2 as well as favorable reproducibility.

Flexible GnPs/EPDM with Excellent Thermal Conductivity and Electromagnetic Interference Shielding Properties

Shaowei Lu,Yaoyao Bai,Jijie Wang,Dandan Chen,Keming Ma,Qingshi Meng,Xinmin Liu 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2019 NANO Vol.14 No.6

As the portable device hardware has been increasing at a noticeable rate, ultrathin flexible materials with the combination of high thermal conductivity and excellent electromagnetic interference (EMI) shielding performance are urgently needed. Here, we fabricated ethylene propylene diene monomer rubber with different loading graphene nanoplatelets (GnPs/EPDM) by a cost-efficient approach, which combines mixing, ultrasonication and compression. Further investigation demonstrates that the 8 wt.% GnPs/EPDM with only 0.3 mm in thickness shows excellent electrical conductivity (28.3 S/m), thermal conductivity (0.79 W/mK) and good mechanical properties. Besides, the 8 wt.% GnPs/EPDM exhibits an EMI shielding effectiveness (SE) up to 33 dB in the X-band (8.2–12.4 GHz) and 35 dB in the Ku-band (12.4–18 GHz), superior to most of the reported rubber matrix. Additionally, the GnPs/EPDM shows excellent flexibility and stability with 95% and 94% retention of EMI SE even after repeated bending for 5000 times and corrosion (under 5% NaCl environment) for a week. Our flexible EMI shielding material will benefit the fast-growing next-generation commercial portable flexible electrons.