21 results on '"motion modes"'
Search Results
2. Quantitative Assessment of Dynamic Stability Characteristics for Jet Transport in Sudden Plunging Motion.
- Author
-
Wang, Yonghu, Zheng, Ran, Zheng, Fujun, Hao, Jinglong, Huang, Xinyu, and Zhao, Juan
- Subjects
JET transports ,DYNAMIC stability ,TRANSPORT planes ,UNSTEADY flow (Aerodynamics) ,NUMERICAL integration ,TRANSONIC aerodynamics ,AIRCRAFT accidents ,AERONAUTICAL safety measures - Abstract
In this paper, we present a monitoring program of loss control prevention for airlines to enhance aviation safety and operational efficiency. The assessments of dynamic stability characteristics based on the approaches of oscillatory motion and eigenvalue motion modes for jet transport aircraft response to sudden plunging motions are demonstrated. A twin-jet transport aircraft encountering severe clear-air turbulence in transonic flight during the descending phase was examined as the study case. The flight results in sudden plunging motions with abrupt changes in attitude and gravitational acceleration (i.e., the normal load factor) are provided. Development of the required thrust and aerodynamic models with the flight data mining and the fuzzy logic modeling techniques was carried out. The oscillatory derivatives extracted from these aerodynamic models were then used in the study of variations in stability characteristics during the sudden plunging motion. The fuzzy logic aerodynamic models were utilized to estimate the nonlinear unsteady aerodynamics while performing numerical integration of flight dynamic equations. The eigenvalues of all motion modes were obtained during time integration. The positive real part of the eigenvalues is to indicate unstable motion. The dynamic stability characteristics during sudden plunging motion are easily judged by the values in positive or negative. The present quantitative assessment method is an innovation to examine possible mitigation concepts of accident prevention and promote the understanding of aerodynamic responses of the jet transport aircraft. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
3. Motion speed control of magnetic microsphere robot under alternating signals.
- Author
-
Ma, Shiqi and Xu, Lizhong
- Subjects
- *
MICROROBOTS , *MOTION analysis , *MAGNETIC fields , *MAGNETIC control , *VOLTAGE , *ROBOT motion - Abstract
Gradient magnetic field driving method does not have strict structural requirements for micro robots, making processing convenient. However, the speed control parameter of micro robots under gradient magnetic fields is single, which limits the practical application of this type of robots. Therefore, this article proposes to use alternating signals to control the motion speed of magnetic microsphere robots. Here, a motion analysis model of a magnetic microsphere robot driven by alternating signals is established, and a formula for calculating the movement speed of the magnetic microsphere robot is provided. The special motion mode of the magnetic microsphere robot driven by alternating signals is considered, and the correctness of the theoretical calculation is verified by experiments. The mechanisms and conditions for the different motion modes of magnetic microsphere robots are revealed. The movement speed of the magnetic microsphere robot under the alternating voltage signals is determined as a function of signal frequency, signal duty cycle, and bias voltage value. The results show that under the alternating voltage signals, the magnetic microsphere robot has three different motion states, namely rotation -movement alternation, swing-movement alternation, and pure movement. There are three control parameters of the speed, which are signal change frequency, duty cycle, and bias voltage. [Display omitted] • A motion analysis model of a magnetic microsphere robot driven by alternating signals is established. • Mechanisms and conditions for the different motion modes of magnetic microsphere robots are revealed. • Speed of the microsphere robot is determined as a function of signal frequency, signal duty cycle, and bias voltage value. • It is found that the magnetic microsphere robot has three different motion states. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
4. Hydrodynamic behavior of inertial elongated microswimmers in a horizontal channel.
- Author
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Ying, Yuxiang, Guan, Geng, and Lin, Jianzhong
- Subjects
- *
LATTICE Boltzmann methods , *DRUG delivery systems , *REYNOLDS number , *SWIMMING equipment , *ENERGY consumption - Abstract
In the current study, the lattice Boltzmann method was used to explore the motion of an elongated microswimmer in a horizontal channel with finite fluid inertia. By employing an extended squirmer rod model, the swimming velocity, hydrodynamic efficiency, and interaction with the channel wall of the capsule-shaped squirmer rod were simulated. It was found that the aspect ratio α and the swimming Reynolds number Re s of the squirmer rod significantly affect its swimming velocity and efficiency. Specifically, as the Reynolds number increases, the pusher rod's velocity increases, whereas the puller rod's velocity decreases. Moreover, compared with the puller rod, the pusher rod has a higher efficiency with the same power consumption. With the increase of the aspect ratio α , the velocity of the squirmer rod increases gradually, the power consumption of the pusher rod and the puller rod decreases gradually, and the efficiency increases gradually, showing the characteristics of lower energy consumption and higher efficiency. During the interaction of the squirmer rod with the wall, four distinct motion modes were identified, namely, steady linear motion, motion away from the wall, damped swinging motion, and wall-attraction oscillation. The emergence of these motion modes and their transitions could be associated with the pressure distribution formed between the squirmer rod and the wall. The results provide another perspective and theoretical basis for the design of bioinspired microswimming devices and microrobots, especially in medical applications such as precision drug delivery systems. • Dynamics characteristics and laws of elongated swimming microorganisms. • As The aspect ratio increases, the squirmer rod has lower power consumption. • The pusher rod is more efficient than the puller rod at the same power consumption. • The formation of different motion modes is related to the pressure distribution. • Providing assistance for the design of more efficient swimming equipment. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
5. Quantitative Assessment of Dynamic Stability Characteristics for Jet Transport in Sudden Plunging Motion
- Author
-
Yonghu Wang, Ran Zheng, Fujun Zheng, Jinglong Hao, Xinyu Huang, and Juan Zhao
- Subjects
flight data mining ,plunging motion ,clear-air turbulence ,stability characteristics ,motion modes ,eigenvalues ,Technology ,Engineering (General). Civil engineering (General) ,TA1-2040 ,Biology (General) ,QH301-705.5 ,Physics ,QC1-999 ,Chemistry ,QD1-999 - Abstract
In this paper, we present a monitoring program of loss control prevention for airlines to enhance aviation safety and operational efficiency. The assessments of dynamic stability characteristics based on the approaches of oscillatory motion and eigenvalue motion modes for jet transport aircraft response to sudden plunging motions are demonstrated. A twin-jet transport aircraft encountering severe clear-air turbulence in transonic flight during the descending phase was examined as the study case. The flight results in sudden plunging motions with abrupt changes in attitude and gravitational acceleration (i.e., the normal load factor) are provided. Development of the required thrust and aerodynamic models with the flight data mining and the fuzzy logic modeling techniques was carried out. The oscillatory derivatives extracted from these aerodynamic models were then used in the study of variations in stability characteristics during the sudden plunging motion. The fuzzy logic aerodynamic models were utilized to estimate the nonlinear unsteady aerodynamics while performing numerical integration of flight dynamic equations. The eigenvalues of all motion modes were obtained during time integration. The positive real part of the eigenvalues is to indicate unstable motion. The dynamic stability characteristics during sudden plunging motion are easily judged by the values in positive or negative. The present quantitative assessment method is an innovation to examine possible mitigation concepts of accident prevention and promote the understanding of aerodynamic responses of the jet transport aircraft.
- Published
- 2022
- Full Text
- View/download PDF
6. Exploring the Allosteric Mechanism of Src Homology-2 Domain-Containing Protein Tyrosine Phosphatase 2 (SHP2) by Molecular Dynamics Simulations
- Author
-
Quan Wang, Wen-Cheng Zhao, Xue-Qi Fu, and Qing-Chuan Zheng
- Subjects
SHP2 ,PD-1 ,MD simulations ,allosteric ,PCA ,motion modes ,Chemistry ,QD1-999 - Abstract
The Src homology-2 (SH2) domain-containing protein tyrosine phosphatase 2 (SHP2, encoded by PTPN11) is a critical allosteric phosphatase for many signaling pathways. Programmed cell death 1 (PD-1) could be phosphorylated at its immunoreceptor tyrosine-based inhibitory motif (ITIM) and immunoreceptor tyrosine-based switch motif (ITSM) and can bind to SHP2 to initiate T cell inactivation. Although the interaction of SHP2-PD-1 plays an important role in the immune process, the complex structure and the allosteric regulation mechanism remain unknown. In this study, molecular dynamics (MD) simulations were performed to study the binding details of SHP2 and PD-1, and explore the allosteric regulation mechanism of SHP2. The results show that ITIM has a preference to bind to the N-SH2 domain and ITSM has almost the same binding affinity to the N-SH2 and C-SH2 domain. Only when ITIM binds to the N-SH2 domain and ITSM binds to the C-SH2 domain can the full activation of SHP2 be obtained. The binding of ITIM and ITSM could change the motion mode of SHP2 and switch it to the activated state.
- Published
- 2020
- Full Text
- View/download PDF
7. Experimental and numerical modeling of particle levitation and movement behavior on traveling-wave electric curtain for particle removal.
- Author
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Zhang Jie, Zhou Chuande, Zheng Fuzhong, Lu Shuhua, Feng Miao, and Tang Yike
- Subjects
- *
LEVITATION , *DRAPERIES , *SOLAR cells , *PARTICLES , *ELECTRIC fields - Abstract
Traveling-wave electric curtain (EC) has been developed for potential application in particle removal/ shield on solar panels and other surfaces. Levitation and transport of a particle in a traveling-wave electric field were simulated. Results show that levitation directions/angles and levitation trajectories differ because of the difference in starting positions and starting times. The particles in the two positive acceleration regions are levitated in opposite directions, and the particles distributed on the dielectric surface are levitated and transported successively rather than simultaneously. Movement trajectories are complex and affected by various factors. In the current paper, movement trajectories are modeled to analyze which motion modes are advantageous or disadvantageous to particle removal. This process is beneficial to elucidate the mechanism of particle removal and provide a guidance for movement control by designing appropriate operating parameters. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
8. Dynamic motion modes of high temperature superconducting maglev on a 45-m long ring test line.
- Author
-
Lei, W. Y., Qian, N., Zheng, J., Jin, L. W., Zhang, Y., and Deng, Z. G.
- Subjects
- *
HIGH temperature superconductivity , *MAGNETIC levitation vehicles , *AUTOMOBILE testing , *CRYOSTATS , *ACCELERATION (Mechanics) - Abstract
With the development of high temperature superconducting (HTS) maglev, studies on the running stability have become more and more significant to ensure the operation safety. An experimental HTS maglev vehicle was tested on a 45-m long ring test line under the speed from 4 km/h to 20 km/h. The lateral and vertical acceleration signals of each cryostat were collected by tri-axis accelerometers in real time. By analyzing the phase relationship of acceleration signals on the four cryostats, several typical motion modes of the HTS maglev vehicle, including lateral, yaw, pitch and heave motions were observed. This experimental finding is important for the next improvement of the HTS maglev system. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
9. Research on a multimodal actuator-oriented power-assisted knee exoskeleton.
- Author
-
Han, Yali, Zhu, Songqing, Zhou, Zhou, Shi, Yu, and Hao, Dabin
- Subjects
- *
ACTUATORS , *KNEE , *ROBOTIC exoskeletons , *ELASTICITY , *MOTION - Abstract
A multimodal actuator was proposed to achieve a more agile power-assisted exoskeleton in uncertain complex walking environments. A power-assisted knee exoskeleton prototype based on a multimodal actuator was constructed. With this multimodal actuator, several modes of operation in the power-assisted knee exoskeleton during a motion cycle are actuated, including series elastic actuation, stiff position control, and energy storage and release. Also, a control strategy for power-assisted knee exoskeleton motion control based on a state machine is developed. The ability of the power-assisted knee exoskeleton to follow human motion was tested, and the results showed that the angle error of the knee exoskeleton followed the human motion is not more than 0.4˚, and the response time error of the knee exoskeleton followed the human motion is not more than 0.2 s. [ABSTRACT FROM PUBLISHER]
- Published
- 2017
- Full Text
- View/download PDF
10. Numerical modeling of particle motion in traveling wave solar panels cleaning device
- Author
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Noureddine Zouzou, Ayyoub Zouaghi, Ampère, Département Energie Electrique (EE), Ampère (AMPERE), École Centrale de Lyon (ECL), Université de Lyon-Université de Lyon-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Institut National des Sciences Appliquées de Lyon (INSA Lyon), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-École Centrale de Lyon (ECL), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Electro-Fluido-Dynamique (EFD ), Département Fluides, Thermique et Combustion (FTC), Institut Pprime (PPRIME), ENSMA-Centre National de la Recherche Scientifique (CNRS)-Université de Poitiers-ENSMA-Centre National de la Recherche Scientifique (CNRS)-Université de Poitiers-Institut Pprime (PPRIME), and ENSMA-Centre National de la Recherche Scientifique (CNRS)-Université de Poitiers-ENSMA-Centre National de la Recherche Scientifique (CNRS)-Université de Poitiers
- Subjects
Displacement velocity ,Dielectric particles ,7. Clean energy ,01 natural sciences ,Motion modes ,Displacement (vector) ,010305 fluids & plasmas ,Coulomb's law ,symbols.namesake ,[SPI]Engineering Sciences [physics] ,Electric field ,0103 physical sciences ,Numerical modeling ,Particle velocity ,Electrical and Electronic Engineering ,Electrostatic forces ,Magnetosphere particle motion ,010302 applied physics ,Physics ,Mechanics ,Condensed Matter Physics ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,Traveling wave ,13. Climate action ,Drag ,symbols ,Particle ,Electric potential ,Biotechnology - Abstract
International audience; One of the promising solutions of dust accumulation on solar panels consists of using electric potential waves to prevent dust adhesion and to remove the dust layer. This study aims to understand the particle motion mechanisms on an electrostatic traveling wave conveyor. Understanding the effect of the operating parameters on particle trajectories and displacement distance is an essential step to improve the efficiency of this device and to understand the factors that can limit its performance. A numerical model that takes into account Coulomb force, dielectrophoretic, and image forces, but also gravity, drag force, and van der Waals adhesion force is carried out. The effect of rotating electric field, frequency, and electric potential harmonics on the particle trajectories and their characteristics are analyzed and discussed. The results reveal that the particles move according to four main movement modes. The frequency is a key parameter to control particle velocity and displacement. A hyper-synchronous movement during which the particles reach velocities much higher than the propagation velocity of the traveling wave has been obtained under certain conditions.
- Published
- 2021
11. Dynamic simulation and modeling of the motion modes produced during the 3D controlled manipulation of biological micro/nanoparticles based on the AFM.
- Author
-
Saraee, Mahdieh B. and Korayem, Moharam H.
- Subjects
- *
DYNAMIC simulation , *THREE-dimensional imaging , *NANOPARTICLES analysis , *CANCER cells , *DNA repair , *ATOMIC force microscopy - Abstract
Determining the motion modes and the exact position of a particle displaced during the manipulation process is of special importance. This issue becomes even more important when the studied particles are biological micro/nanoparticles and the goals of manipulation are the transfer of these particles within body cells, repair of cancerous cells and the delivery of medication to damaged cells. However, due to the delicate nature of biological nanoparticles and their higher vulnerability, by obtaining the necessary force of manipulation for the considered motion mode, we can prevent the sample from interlocking with or sticking to the substrate because of applying a weak force or avoid damaging the sample due to the exertion of excessive force. In this paper, the dynamic behaviors and the motion modes of biological micro/nanoparticles such as DNA, yeast, platelet and bacteria due to the 3D manipulation effect have been investigated. Since the above nanoparticles generally have a cylindrical shape, the cylindrical contact models have been employed in an attempt to more precisely model the forces exerted on the nanoparticle during the manipulation process. Also, this investigation has performed a comprehensive modeling and simulation of all the possible motion modes in 3D manipulation by taking into account the eccentricity of the applied load on the biological nanoparticle. The obtained results indicate that unlike the macroscopic scale, the sliding of nanoparticle on substrate in nano-scale takes place sooner than the other motion modes and that the spinning about the vertical and transverse axes and the rolling of nanoparticle occur later than the other motion modes. The simulation results also indicate that the applied force necessary for the onset of nanoparticle movement and the resulting motion mode depend on the size and aspect ratio of the nanoparticle. [ABSTRACT FROM AUTHOR]
- Published
- 2015
- Full Text
- View/download PDF
12. Time‐varying formation control for high‐order linear swarm systems with switching interaction topologies.
- Author
-
Dong, Xiwang, Shi, Zongying, Lu, Geng, and Zhong, Yisheng
- Abstract
Time‐varying formation control problems for high‐order linear time‐invariant swarm systems with switching interaction topologies are investigated. A general formation control protocol is proposed firstly. Then using a consensus based approach, necessary and sufficient conditions for swarm systems with switching interaction topologies to achieve a given time‐varying formation are presented. An explicit expression of the time‐varying formation reference function is given. It is revealed that the switching interaction topologies have no effect on the formation reference function and the motion modes of the formation reference can be specified. Furthermore, necessary and sufficient conditions for formation feasibility are presented. An approach to expand the feasible formation set is given and an algorithm to design the protocol for swarm systems with switching interaction topologies to achieve time‐varying formations is provided. Finally, numerical simulations are presented to demonstrate theoretical results. [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
- View/download PDF
13. Motion of fine-spray liquid droplets in hot gas flow.
- Author
-
Kuznetsov, G., Kuibin, P., and Strizhak, P.
- Abstract
Experimental study was performed on motion of fine-spray liquid (water) droplets in a high-temperature (above 1000 K) gases. The study distinguishes three modes of droplet motion through gas medium under condition of intensive evaporation. Experiments defined the ranges of gas velocity, droplets sizes, and velocities that correspond to the droplet motion modes. [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
- View/download PDF
14. Investigating the motion modes of smooth/rough micro/nanoparticles with circular crowned roller geometry and computing the maximum force
- Author
-
Korayem, M. H., Mahmoodi, Z., and Mirmohammad, S. A.
- Published
- 2019
- Full Text
- View/download PDF
15. Mechanism of instability of a single bubble at low Reynolds numbers.
- Author
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Arkhipov, V., Vasenin, I., and Usanina, A.
- Subjects
- *
REYNOLDS number , *PHYSICS experiments , *SYMMETRY (Physics) , *PERTURBATION theory , *DEFORMATIONS (Mechanics) , *FLUID dynamics , *NUMBER theory - Abstract
The mechanism of shape instability of a bubble moving at low Reynolds numbers is analyzed by theoretical and experimental studies of axisymmetric perturbations of the spherical interface. It is shown that, under such conditions, deformation of the initially spherical bubble is due to the development of Rayleigh-Taylor instability upon reaching a critical Bond number. [ABSTRACT FROM AUTHOR]
- Published
- 2011
- Full Text
- View/download PDF
16. Stability and control analysis of rotor/ducted-fan based unmanned helicopter.
- Author
-
WANG Hong-qiang, WANG Dao-bo, and Duan Hai-bin
- Subjects
HELICOPTERS ,DUCTED fans ,REMOTELY piloted vehicles ,ROTORS (Helicopters) ,COUPLINGS (Gearing) ,MATHEMATICS - Abstract
Taken into consideration of the effect of rotor downwash and shrouding duct, the Pitt-Peters' first harmonic non-uniform dynamic inflow model is extended to modeling the rotor/ducted fan propellant system. Combined with the data of wind tunnel experiment of assembled fan and duct fuselage, a practical nonlinear mathematical model of a full-scale rotor/ducted-fan helicopter is derived. The derived nonlinear model is linearized and the analysis of flight dynamics of the rotor/ducted-fan helicopter is conducted. The analysis results are compared with the flight dynamics of a conventional helicopter. It is indicated that the distinguishing features of the rotor/ducted-fan helicopter from the conventional helicopter are predominantly in the stability of lateral-directional motion modes at different flight speeds and the coupling characteristics of response to control inputs. [ABSTRACT FROM AUTHOR]
- Published
- 2009
17. On models of dynamic systems with dry friction.
- Author
-
Antonyuk, E. Ya.
- Subjects
- *
MACHINE bearing design & construction , *SYSTEMS design , *CONTROL theory (Engineering) , *TRANSFER functions , *AUTOMATIC control systems , *DRY friction , *SYSTEM analysis - Abstract
An approach to the design of models of dynamical systems with high dry friction in the kinematic pair is developed. The members of the kinematic pair are represented by parts of rigid bodies. The system as a whole is considered to have a variable structure. According to this assumption, two modes of motion with different dissipative characteristics are possible. The states in which the modes exchange and the motion switches over into critical modes with dynamic self-locking are established. A system with a variable transfer function between members that form a nonideal constraint is described [ABSTRACT FROM AUTHOR]
- Published
- 2007
- Full Text
- View/download PDF
18. Numerical simulation on joint motion process of various modes of caisson breakwater under wave excitation.
- Author
-
Wang Yuan-Zhan, Chen Nan-Nan, and Chi Li-Hua
- Subjects
- *
HYDRAULIC structures , *VIBRATION (Aeronautics) , *BREAKWATERS , *STRUCTURAL engineering , *HYDRAULIC engineering - Abstract
A caisson breakwater may experience various modes of motions under wave action. The elementary motion modes are classified into two categories, i.e. the horizontal and rotational vibration coupled motion and the horizontal slide and rotational vibration coupled motion. The motion modes of caisson will transform from one to another depending on the wave forces and the motion behaviours of a caisson. The numerical models of the two motion modes of caisson are developed, the numerical simulation procedure for joint motion process of the two modes of caisson breakwater under wave excitation is presented and tested by a physical model experiment. It is concluded that the simulation procedure is reliable and can be applied to the dynamic stability analysis of caisson breakwaters. Copyright © 2005 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]
- Published
- 2006
- Full Text
- View/download PDF
19. Numerical modeling of particle motion in traveling wave solar panels cleaning device.
- Author
-
Zouaghi, Ayyoub and Zouzou, Noureddine
- Subjects
- *
PARTICLE motion , *SOLAR panels , *VAN der Waals forces , *ELECTRIC field effects , *ELECTRICAL harmonics , *DRAG force - Abstract
One of the promising solutions of dust accumulation on solar panels consists of using electric potential waves to prevent dust adhesion and to remove the dust layer. This study aims to understand the particle motion mechanisms on an electrostatic traveling wave conveyor. Understanding the effect of the operating parameters on particle trajectories and displacement distance is an essential step to improve the efficiency of this device and to understand the factors that can limit its performance. A numerical model that takes into account Coulomb force, dielectrophoretic, and image forces, but also gravity, drag force, and van der Waals adhesion force is carried out. The effect of rotating electric field, frequency, and electric potential harmonics on the particle trajectories and their characteristics are analyzed and discussed. The results reveal that the particles move according to four main movement modes. The frequency is a key parameter to control particle velocity and displacement. A hyper-synchronous movement during which the particles reach velocities much higher than the propagation velocity of the traveling wave has been obtained under certain conditions. • Numerical modeling of the particles motion in electrostatic traveling waves. • Study of the effect of the frequency and the spatial harmonics on the particles motion. • Consideration of the drag force, gravity force, Coulomb force, dielectrophoretic force, image force, and Van der Waals force. • Study of the displacement distance, velocity, and the trajectory of the particle. • Recommandations to improve the particle displacement efficiency for solar panels cleaning application. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
20. Exploring the Allosteric Mechanism of Src Homology-2 Domain-Containing Protein Tyrosine Phosphatase 2 (SHP2) by Molecular Dynamics Simulations.
- Author
-
Wang Q, Zhao WC, Fu XQ, and Zheng QC
- Abstract
The Src homology-2 (SH2) domain-containing protein tyrosine phosphatase 2 (SHP2, encoded by PTPN11 ) is a critical allosteric phosphatase for many signaling pathways. Programmed cell death 1 (PD-1) could be phosphorylated at its immunoreceptor tyrosine-based inhibitory motif (ITIM) and immunoreceptor tyrosine-based switch motif (ITSM) and can bind to SHP2 to initiate T cell inactivation. Although the interaction of SHP2-PD-1 plays an important role in the immune process, the complex structure and the allosteric regulation mechanism remain unknown. In this study, molecular dynamics (MD) simulations were performed to study the binding details of SHP2 and PD-1, and explore the allosteric regulation mechanism of SHP2. The results show that ITIM has a preference to bind to the N-SH2 domain and ITSM has almost the same binding affinity to the N-SH2 and C-SH2 domain. Only when ITIM binds to the N-SH2 domain and ITSM binds to the C-SH2 domain can the full activation of SHP2 be obtained. The binding of ITIM and ITSM could change the motion mode of SHP2 and switch it to the activated state., (Copyright © 2020 Wang, Zhao, Fu and Zheng.)
- Published
- 2020
- Full Text
- View/download PDF
21. M-mode state based identification in ultrasound videos of the atherosclerotic carotid plaque
- Author
-
Loizou, Christos P., Pantzaris, Marios C., Pattichis, Constantinos S., Kyriacou, Efthyvoulos C., Pattichis, Constantinos S. [0000-0003-1271-8151], Kyriacou, Efthyvoulos C. [0000-0002-4589-519X], Loizou, Christos P. [0000-0003-1247-8573], and Pantzaris, Marios C. [0000-0003-2937-384X]
- Subjects
Signal processing ,Motion analysis ,Monitoring ,Medical Engineering ,Diastole ,Distension ,Motion modes ,Mode-state ,Videos ,Cardiac disease ,Medicine ,Computer vision ,Ultrasonics ,Carotid plaques ,Cardiac cycles ,Image segmentation ,State-based ,Cardiac cycle ,Wall thickness ,business.industry ,Ultrasonic imaging ,Ultrasound ,Atherosclerotic disease ,Atherosclerosis ,Carotid arteries ,medicine.anatomical_structure ,M-mode echocardiography images ,Corresponding state ,Engineering and Technology ,Artificial intelligence ,M-mode representation ,business ,Carotid artery ,Biomedical engineering ,Artery - Abstract
Monitoring the wall and plaque changes in the carotid artery (CA) can provide useful information for the assessment of the atherosclerotic disease. Using a motion mode (M-mode) image, detailed information may be obtained about wall and lumen dimensions, systolic and diastolic artery diameter and distension, wall and plaque motion and thickness, and also their corresponding states (timings). The wall thickness and the diameter of the CA change during the cardiac cycle are an indicator of regional contraction and therefore an indication of a disease. The objective of this work was to investigate how M-mode state based modeling of the CA can be derived from a B-mode ultrasound video. Briefly, 10 longitudinal CA ultrasound videos acquired from symptomatic subjects at risk of atherosclerosis were broken into frames and their M-mode images were generated. These were then despeckled and the atherosclerotic carotid plaque was segmented from each video, in order to extract the states of the video. By identifying the states of the CA, we can distinguish between normal and abnormal plaque motion. It was shown in this work, that M-mode state based modeling derived from B-mode videos can be used successfully to derive the carotid states and assess the corresponding wall changes. However, further work in a larger number of videos is needed for validating the proposed method and to differentiate between normal and abnormal state based plaque motion analysis. ©2010 IEEE. Sponsors: Cyprus University of Technology University of Cyprus Conference code: 80672 Cited By :8
- Published
- 2010
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