Clockwise Research Articles

In-plane spin excitation of skyrmion bags

Skyrmion bags are spin structures with arbitrary topological charges, each of which is composed of a big skyrmion and several small skyrmions. In this work, by using an in-plane alternating current (AC) magnetic field, we investigate the spin-wave modes of skyrmion bags, which behave differently from the clockwise (CW) rotation mode and the counterclockwise (CCW) rotation mode of skyrmions because of their complex spin topological structures. The in-plane excitation power spectral density shows that each skyrmion bag possesses four resonance frequencies. By further studying the spin dynamics of a skyrmion bag at each resonance frequency, the four spin-wave modes, i.e., a CCW-CW mode, two CW-breathing modes with different resonance strengths, and an inner CCW mode, appear as a composition mode of outer skyrmion–inner skyrmions. Our results are helpful in understanding the in-plane spin excitation of skyrmion bags, which may contribute to the characterization and detection of skyrmion bags, as well as the applications in logic devices.

PO-01-138 NON-INVASIVE 3-D MAPPING (ECGI) OF MACRO-REENTRANT ATRIAL ARRHYTHMIAS

Peri-valvular atrial arrhythmias are the most common macro-reentrant mechanism seen in both de-novo and repeat atrial fibrillation (AF) ablations. Standard 12-lead ECG’s poorly predict tachycardia mechanisms especially post AF ablation. Identifying the mechanism of tachycardia non-invasively could help in procedural planning, expedite the invasive procedure, and identify critical areas sustaining persistent AF in patients with concomitant AF. The objective was to determine if ECGi could identify the mechanism of atrial flutters in patients with or without prior AF ablations. 30 patients (11 de-novo, 19 prior ablation) underwent non-invasive propagation and phase mapping (CardioInsight, Medtronic, Inc) and intracardiac bi-atrial high-density activation mapping (HD Grid and Precision, Abbott Medical). An 8-segment model (RA lateral, RA anterior, CTI, Septum, LA anterior, LA lateral, CS, LA posterior) was used for directionality in the propagation maps, and a 9-segment model for phase map analysis was used for presence and localization of ‘rotational hinge points’ which can occur with wavefronts moving in different directions within close proximity. The precise tachycardia mechanism (counterclockwise (CCW) or clockwise (CW) and cavo-tricuspid isthmus (CTI) or mitral isthmus (MI) dependent) was determined by intracardiac activation maps, entrainment, and confirmed with termination by ablation. Directionality in a region was deemed concordant if non-invasive and intracardiac maps matched or was declared discordant/indeterminate. A total of 31 macro-reentrants maps were analyzed: 16 CCW-CTI; 7 CW-CTI; 4 CCW-MI; 4 CW-MI. Regional directional concordance percentages shown in theTable. A total of 30/31 phase maps identified at least one region as a 'rotational hinge point', with 26/31 maps showing paired 'hinge points'. Location of rotations are shown in the Figure. ECGi can be used in macro-reentant atrial arrhythmias to determine directionality of activation with best concordance on the lateral walls of both atria. In our study, 97% of peri-valvular atrial flutters had at least one 'rotational hinge point' with 84% showing them paired representing macro-reentant circuit. Posterior LA wall rotational area was present in all peri-mitral flutters. Additionally, paired 'hinge points' with lateral atrial wall directionality were the best determinants of the macro-reentant mechanism.Tabled 1Directional ConcordanceRA LatRA AntCTISeptumLA AntLA LatCSLA PostCCW-CTI88%69%88%44%44%--50%--CW-CTI71%43%71%43%43%--29%--CCW-MI100%50%--75%75%100%100%50%CW-MI100%60%--40%40%80%80%20% Open table in a new tab

PO-01-028 LEAD HELIX FAILS TO RETRACT DURING LEFT BUNDLE BRANCH AREA PACING IMPLANT

Left bundle branch area pacing has emerged as the preferred method of conduction system pacing due to the lead stability and the stable low thresholds. The leads are lumenless leads or stylet driven leads The long term impact of these leads has not been well established. In this case, we describe removing a stylet driven lead in the left bundle branch area for repositioning N/A A 76 year old male presented for pacemaker implant for sick sinus syndrome. It was decided to implant a dual chamber pacemaker with left bundle branch area pacing. Using a stylet driven lead (Biotronik Solia S60, SE & Co, Berlin, Germany), and Selectra 3D sheath (Biotronik, SE & Co, Berlin, Germany), site was found on the right ventricular septum to advance lead into left bundle branch area. Helix deployed. Lead was driven into the septum with one to one lead body turns with lead helix turns (Figure A). Left bundle branch area pacing was demonstrated. Lead sensing and pacing parameters were acceptable. Sheath was split and decrease in sensing with increase in threshold was seen. It was decided to remove the lead to reposition. Counter clockwise turns were applied to the helix mechanism. Helix would not retract. Counter clockwise turns applied to the lead body and the lead would not release from the septum. Counter traction was applied to the lead and helix was noted to stretch on fluoroscopy. With further traction, lead was removed from the body in one piece. On gross inspection of the lead, a stretched helix was noted with probably a piece of the tricuspid valve apparatus. A standard right ventricular septal pacing lead was implanted, and the dual chamber pacemaker was completed. Post operative echo did not show any significant tricuspid regurgitation. Left bundle area pacing has emerged given its physiological pacing with stable position and lead parameters. The long term implications of these leads driven deep into the septum have not been established. Our case demonstrated potential pitfall of stylet driven leads for left bundle branch area pacing, which is the helix. This draws concern that future helixes of left bundle branch area leads may break off in the septum. Further long term evaluation of these leads is warranted.

Design Parameters of Automatic Drilling & Tapping Machine

Abstract: This paper focuses on design of machine which can perform drilling and tapping processes together with the help of automation in order to improves production, reduce time for manufacturing and manufacture economically on a bigger scale. In regular drilling process which is the most common way to put a hole in metal or other materials, for precise hole location, good finish and accurate size automatic drilling machine is required. To cut threads on hole accurately along with the drilling process we using drill cum tapping bit. Tapping operation required to rotate the spindle in both clockwise and counter clockwise direction. So, we have made bevel gear arrangement for reversal of the spindle and also worm and worm gear is used for speed reduction as drilling requires high RPM and tapping requires low RPM to perform the drill and internal threads.

Effects of tool grip span, workpiece orientation, moving direction, and working height on two-handed torque strength and subjective measures.

Using both hands is regularly needed for force/torque exertions in many activities, especially when using hand tools. To investigate the effects of tool grip span, workpiece orientation, moving direction, and working height on two-handed wrist U/R deviation torque strength, usability, comfort, and discomfort while using locking pliers. Participants (n = 22) took part in an experimental study which evaluated the effects of tool grip span (4.5-6.5 cm), workpiece orientation (transverse/sagittal), moving direction (clockwise (CW)/counterclockwise (CCW)), and working height (shoulder/elbow/knuckle) on two-handed wrist U/R deviation torque, (dis)comfort, and usability while using locking pliers. The results showed no significant effect of tool grip span on wrist U/R deviation torque strength, but the locking pliers with 4.5 cm handle grip span led to more comfort and better usability. The two-handed wrist U/R deviation torque strengths were significantly higher in sagittal plane than in transverse plane, and in CW direction than in CCW direction. The highest values of two-handed wrist U/R deviation torque strength in sagittal and transverse planes were exerted in knuckle and elbow heights, respectively. The findings can be used to develop guidelines and recommendations with regard to daily and occupational activities which require the use of both hands for force exertion with manual hand tools.

Differential Bending Stiffness of the Bacterial Flagellar Hook under Counterclockwise and Clockwise Rotations.

The bacterial hook, as a universal joint coupling rotation of the flagellar motor and the filament, is an important component of the flagellum that propels the bacteria to swim. The mechanical properties of the hook are essential for the flagellum to achieve normal functions. In multiflagellated bacteria such as Escherichia coli, the hook must be compliant so that it can bend for the filaments to form a coherently rotating bundle to generate the thrust when the motor rotates counterclockwise (CCW), yet it also must be rigid so that the bundle can disrupt for the bacteria to tumble to change swimming direction when the motor rotates clockwise (CW). Here, by combining an elastic rod model with high-resolution bead assay to accurately measure the bending stiffness of the hook under CCW or CW rotation invivo, we elucidate how the hook accomplishes this dual functionality: the hook stiffens under CW rotation, with bending stiffness under CW rotation twice as large as that under CCW rotation. This enables a robust run-and-tumble swimming motility for multiflagellated bacteria.

Finite Element Analysis of Maxillary Teeth Movement with Time during En Masse Retraction Using Orthodontic Mini-Screw

Introduction: The aim of this study was to determine the placement of an orthodontic mini-screw (OMS) and the length of an anterior retraction hook (ARH) with en masse retraction. Continuous maxillary tooth movement pattern was simulated by finite element analysis (FEA). Materials and methods: Extraction of the first premolar was hypothesized with a finite element model. The placement of OMS was analyzed for the following two groups: (1) a high OMS (HOMS) group with OMS placed horizontally at the mesial side of the second premolar and apically 10 mm above the arch wire, and (2) a low OMS (LOMS) group with OMS placed horizontally between the second premolar and the first molar and apically 8 mm above the arch wire. According to the height of ARH, each group was divided into three subgroups. Results: When the extraction space of the first premolar was closed, anterior teeth were intruded in the HOMS group but extruded in the LOMS group. In all cases, the first molar was intruded. According to the intrusion of the first molar and extrusion of anterior teeth, the occlusal plane rotated clockwise (CW) in the LOMS group. However, in the HOMS1 group, the occlusal plane rotated counterclockwise (CCW) due to more intrusion of anterior teeth than that of the first molar. Conclusion: By analyzing six cases of different OMS and ARH, changes of incisor and molar in en masse retraction with the extraction of the first premolar could be predicted. In addition, OMS placement and ARH length can be determined based on results of incisal showing. This study can also help esthetic orthodontic results.

Novel magneto-radiative thermal featuring in SWCNT–MWCNT/C2H6O2–H2O under hydrogen bonding

Hybrid nanofluids have unique characteristics that make them more useful than common heat transfer fluids. The potential applications can be found in applied thermal engineering, chemical engineering, hybrid powered engines, biomedical and mechanical engineering. Therefore, the analysis of SWCNTs–MWCNTs/C2H6O2–H2O with integrated effects of thermal radiations and perpendicular magnetic field is organized in this research. Thermal conductivity of C2H6O2–H2O is improved via Xue, Ota and Yamada thermal conductivity correlations. The mathematical problem is designed for two sheets and both the hybrid nanoliquid and the plates rotate in counter clockwise pattern. Mathematical treatment of the model is performed and the results were analyzed through graphical way. Keen observations of the results reveal that the fluid motion controlled by intensifying the magnetic field and higher density of SWCNTs–MWCNTs leads to optimum decrement. Further, the fluid movement is investigated optimum and slow for outward and inward plate movement, respectively. The temperature results for the parameters, especially the thermal radiations, showed that hybrid nanoliquid has the ability to store high thermal energy than common mono-nanoliquid, hence it would be suitable for future industrial applications. The parametric ranges are selected as [Formula: see text]–1.7, [Formula: see text]–0.9, [Formula: see text]–9.0 and [Formula: see text]–20.0 for the study.

Bio-inspired in silico microswimmer: Run and tumble kinematics

We present an in silico microswimmer motivated by peritrichous bacteria, E. coli, which can run and tumble by spinning their flagellar motors counterclockwise (CCW) or clockwise (CW). Runs are the directed movement driven by a flagellar bundle, and tumbles are reorientations of cells caused by some motors' reversals from CCW to CW. In a viscous fluid without obstacles, our simulations reveal that material properties of the hook and the counterrotation of the cell body are important factors for efficient flagellar bundling and that longer hooks in mutant cell models create an instability and disrupt the bundling process, resulting in a limited range of movement. In the presence of a planar wall, we demonstrate that microswimmers can explore environment near surface by making various types of tumble events as they swim close to the surface. In particular, the variation of tumble duration can lead the microswimmer to run in a wide range of direction. However, we find that cells near surface stay close to the surface even after tumbles, which suggests that the tumble motion may not promote cells' escape from the confinement but promote biofilm formation.

Microbial stir bars: Light-activated rotation of tethered bacterial cells to enhance mixing in stagnant fluids.

Microfluidics devices are gaining significant interest in biomedical applications. However, in a micron-scale device, reaction speed is often limited by the slow rate of diffusion of the reagents. Several active and passive micro-mixers have been fabricated to enhance mixing in microfluidic devices. Here, we demonstrate external control of mixing by rotating a rod-shaped bacterial cell. This rotation is driven by ion transit across the bacterial flagellar stator complex. We first measured the flow fields generated by rotating a single bacterial cell rotationally locked to rotate either clockwise (CW) or counterclockwise (CCW). Micro-particle image velocimetry (μPIV) and particle tracking velocimetry results showed that a bacterial cell of ∼ 2.75 μm long, rotating at 5.75 ± 0.39 Hz in a counterclockwise direction could generate distinct micro-vortices with circular flow fields with a mean velocity of 4.72 ± 1.67 μm/s and maximum velocity of 7.90 μm/s in aqueous solution. We verified our experimental data with a numerical simulation at matched flow conditions, which revealed vortices of similar dimensions and speed. We observed that the flow-field diminished with increasing z-height above the plane of the rotating cell. Lastly, we showed that we could activate and tune rotational mixing remotely using strains engineered with proteorhodopsin, where rotation could be activated by controlled external illumination using green laser light (561 nm).

Experimental investigation of the effect of mechanical vibration and rotating magnetic field on the hydrothermal performance of water-Fe3O4 ferrofluid inside a rifled tube

Vibration can enhance the hydrothermal performance by disturbing the thermal boundary layer. Also, the magnetic field increases the ferrofluid mixing, thereby enhancing the heat transfer rate. In this study, an experimental analysis of ferrofluid flow inside a rifled tube under the vibration and rotational magnetic field (RMF) effects was conducted by considering different Reynolds numbers (Re), nanoparticle concentrations (φ), and rifled tube pitches (P). In the first stage, the effect of Re and φ on the hydrothermal performance of the system in the absence of the vibration and RMF was explored. In the second stage, the effect of vibration on the performance evaluation criterion (PEC) of the system was investigated. Finally, the RMF effect was considered. Based on the results, the system with P = 5 mm showed the highest PEC in all experiments. The highest PEC without the vibration and RMF effects was obtained as 1.62 for P = 5 mm and φ = 0% at Re = 2000. The highest PEC under the vibration effect (1.28) was also found for Re = 2000 but at φ of 2%, when the highest vibration acceleration (5 m/s2) was applied. Among the RMFs examined, the RMF with the counter clock-wise along with the counter clock-wise fluid flow inside the rifled tube resulted in the highest PEC of 1.62. RMF improved the PEC of the system from 1.28 to 1.62, corresponding to a 21.32% increase, under the vibration.

Neuropsychological Evidence Underlying Counterclockwise Bias in Running: Electroencephalography and Functional Magnetic Resonance Imaging Studies of Motor Imagery

We aimed to answer the question "why do people run the track counterclockwise (CCW)?" by investigating the neurophysiological differences in clockwise (CW) versus CCW direction using motor imagery. Three experiments were conducted with healthy adults. Electroencephalography (EEG) was used to examine hemispheric asymmetries in the prefrontal, frontal, and central regions during CW and CCW running imagery (n = 40). We also evaluated event-related potential (ERP) N200 and P300 amplitudes and latencies (n = 66) and conducted another experiment using functional magnetic resonance imaging (fMRI) (n = 30). EEG data indicated greater left frontal cortical activation during CCW imagery, whereas right frontal activation was more dominant during CW imagery. The prefrontal and central asymmetries demonstrated greater left prefrontal activation during both CW and CCW imagery, with CCW rotation exhibiting higher, though statistically insignificant, asymmetry scores than CW rotation. As a result of the fMRI experiment, greater activation was found during CW than during CCW running imagery in the brain regions of the left insula, Brodmann area 18, right caudate nucleus, left dorsolateral prefrontal cortex, left superior parietal cortex, and supplementary motor area. In the ERP experiment, no significant differences were found depending on direction. These findings suggest that CCW rotation might be associated with the motivational approach system, behavioral activation, or positive affect. However, CW rotation reflects withdrawal motivation, behavioral inhibition, or negative affect. Furthermore, CW rotation is understood to be associated with neural inefficiency, increased task difficulty, or unfamiliarity.

Microfiber assisted bidirectional wavelength-locked ultrafast erbium-doped fiber laser

Bidirectional mode-locked fiber lasers are promising media to implement intracavity phase interferometry (IPI) due to the ability to produce ultrashort pulses in a compact design. A typical bidirectional ultrafast fiber laser will generate counter-propagating pulses with different repetition rates due to the asymmetric constructure. In this paper, by using the filtering effect of microfiber, an asymmetric bidirectional fiber laser that emits two pulses with same operation wavelength is demonstrated. The utilization of microfiber in locking output wavelength from two directions may directly simplify the design of laser cavity suitable for IPI applications. Moreover, continuous wavelength tuning in a single-cavity bidirectional ultrafast fiber laser has been realized for the first time by applying strain on the microfiber. In the clockwise (CW) direction, wavelength tuning ranges from 1558.96 nm to 1567.3 nm and from 1558.93 nm to 1567.25 nm in the counter clockwise (CCW) direction. The counter-circulating pulses maintain spectral locking state during the whole wavelength tuning process with a good linear sensitivity of 0.2 nm/µm. Such features may further expand the scope and field of fiber lasers for sensing.

Asymmetric surface texturing for directional friction control under dry sliding condition

This study investigated the effects of asymmetric surface texturing on directional friction under dry condition. Asymmetric micro-grooves were radially textured on electroless nickel phosphorous (Ni–P) plated disk using a single-point diamond cutting process. Using a ball-on-disk tribometer, sliding tests in clockwise (CW) and counter-clockwise (CCW) directions against polyether-ether-ketones (PEEK) material were carried out at different texture densities. Results show that asymmetric surface texturing has a strong effect on directional friction. At a texture density of 70 %, the friction coefficient in the CW direction increased by 28.1 % compared to the CCW direction. The greatest increase in friction coefficient, 61.3 %, was observed during CW rotation at the lowest texture density compared to the reference untextured surface.

The Actin Crosslinker Fascin Regulates Cell Chirality.

The left-right (L-R) asymmetry of the cells, or cell chirality, is a well-known intrinsic property derived from the dynamic organization of the actin cytoskeleton. Cell chirality can be regulated by actin-binding proteins such as α-actinin-1 and can also be mediated by certain signaling pathways, such as protein kinase C (PKC) signaling. Fascin, an actin crosslinker known to mediate parallel bundling of actin filaments, appears as a prominent candidate in cell chirality regulation, given its role in facilitating cell migration as an important PKC substrate. Here, it is shown that the chirality of NIH/3T3 cells can be altered by PKC activation and fascin manipulation. With either small-molecule drug inhibition or genetic knockdown of fascin, the chirality of 3T3 cells is reversed from a clockwise (CW) bias to a counterclockwise (CCW) bias on ring-shaped micropatterns, accompanied by the reversal in cell directional migration. The Ser-39 fascin-actin binding sites are further explored in cell chirality regulation. The findings of this study reveal the critical role of fascin as an important intermediator in cell chirality, shedding novel insights into the mechanisms of L-R asymmetric cell migration and multicellular morphogenesis.

RANDOM WAYPOINT MOBILITY ROUTING ALGORITHM FOR MOBILE SENSOR NETWORKS

Mobile Sensor Network an emerging trend in recent network platform. Random waypoint mobility routing proposed on virtual infrastructure based mobile sensor network. Routing is highly challenging task in mobile sensor network, in which the random waypoint model used to ascertain through put and energy depletion. Sensor network classified into multiple regions. Scheduled time slot is assigned for data transmission in between source to sink. Routing table is periodically updated with its neighborhood information. In order to discovers sink node random waypoint mobility routing algorithm checks either clockwise or anti clockwise in the region to find an optimal route for reliable data transmission. In comparison to other cutting-edge cluster-based routing protocols, the effectiveness of the suggested technique assessed using the essential network characteristics. In addition proposed algorithm reduces normalized routing overhead and reselection of region head by varying the node density in the network.

Stable and Tunable PT-Symmetric Single-Longitudinal-Mode Fiber Laser Using a Nonreciprocal Sagnac Loop

A stable and tunable parity-time (PT) symmetric single-longitudinal-mode fiber laser using a nonreciprocal Sagnac loop is proposed, which is experimentally and numerically demonstrated. The nonreciprocal Sagnac loop only including a 3-dB optical coupler (OC) and a polarization controller (PC) is incorporated into a fiber ring cavity, in which nonreciprocal light transmission between the frequency-degenerate clockwise (CW) and counterclockwise (CCW) resonator modes is induced to suppress multiple-longitudinal-mode oscillation of the laser. The two light paths along the CW and CCW directions in the Sagnac loop are respectively defined as the gain and loss loop of the PT-symmetric laser, due to a controllable birefringence induced by the PC. By controlling the polarization states of the two light waves, the PT symmetry is broken when the gain coefficient is larger than the coupling coefficient, single-mode lasing is thus achieved. Experimental results show that the optical signal to noise ratio (OSNR) of the single-mode lasing at 1550 nm is 43.0 dB, proving the great superiority of PT symmetry for lasing mode selection. By tuning an optical tunable band-pass filter incorporated into the fiber cavity, the wavelength of output single-mode lasing varies from 1530 to 1560 nm, and their 3-dB Lorentzian linewidth varies within a range from 529 to 687 Hz. During a 30-min observation period, the variations of wavelength drift and OSNR of the single-mode lasing are less than 6 pm and 2.42 dB, respectively. The advantages of the proposed scheme are obvious, which include simple structure, low cost, simple operation, and good stability.

Active foam: the adaptive mechanics of 2D air-liquid foam under cyclic inflation.

Foam is a canonical example of disordered soft matter where local force balance leads to the competition of many metastable configurations. We present an experimental and theoretical framework for "active foam" where an individual voxel inflates and deflates periodically. Local periodic activity leads to irreversible and reversible T1 transitions throughout the foam, eventually reaching a reversible limit cycle. Individual vertices displace outwards and subsequently return back to their approximate original radial position; this radial displacement follows an inverse law. Surprisingly, each return trajectory does not retrace its outbound path but encloses a finite area, with a clockwise (CW) or counterclockwise (CCW) direction, which we define as a local swirl. These swirls form coherent patterns spanning the scale of the material. Using a dynamical model, we demonstrate that swirl arises from disorder in the local micro-structure. We demonstrate that disorder and strain-rate control a crossover between cooperation and competition between swirls in adjacent vertices. Over 5-10 cycles, the region around the active voxel structurally adapts from a higher-energy metastable state to a lower-energy state, locally ordering and stiffening the structure. The coherent domains of CW/CCW swirl become smaller as the system stabilizes, indicative of a process similar to the Hall-Petch effect. Finally, we introduce a statistical model that evolves edge lengths with a set of rules to explore how this class of materials adapts as a function of initial structure. Adding activity to foam couples structural disorder and adaptive dynamics to encourage the development of a new class of abiotic, cellularized active matter.

Flagellar polymorphism-dependent bacterial swimming motility in a structured environment.

Most motile bacteria use supramolecular motility machinery called bacterial flagellum, which converts the chemical energy gained from ion flux into mechanical rotation. Bacterial cells sense their external environment through a two-component regulatory system consisting of a histidine kinase and response regulator. Combining these systems allows the cells to move toward favorable environments and away from their repellents. A representative example of flagellar motility is run-and-tumble swimming in Escherichia coli, where the counter-clockwise (CCW) rotation of a flagellar bundle propels the cell forward, and the clockwise (CW) rotation undergoes cell re-orientation (tumbling) upon switching the direction of flagellar motor rotation from CCW to CW. In this mini review, we focus on several types of chemotactic behaviors that respond to changes in flagellar shape and direction of rotation. Moreover, our single-cell analysis demonstrated back-and-forth swimming motility of an original E. coli strain. We propose that polymorphic flagellar changes are required to enhance bacterial movement in a structured environment as a colony spread on an agar plate.

Movement pattern and upper extremity muscle activation during fast and slow continuous steering movement

Continuous steering movement (CSM) is an essential component of the upper extremity (UE) task during vehicle driving, and could be a suitable candidate for multi-joint rehabilitation programs for patients with UE disabilities. This study aims to evaluate the UE muscle activation during CSM and how the rotating speed and direction affect CSM's kinematic and kinetic performance. Surface electromyography (EMG), hand contact information, and steering torque were measured under fast (180°/s) and slow (60°/s) constant-velocity CSM to reveal the activation of shoulder and elbow muscles, temporal characteristics, and force exertion during the stance and swing phases of a CSM cycle. Data from 24 normal young adults showed that shorter contact duration but higher force exertion occurred in the hand moving in an outward steering direction during only fast CSM in either the clockwise (CW) or counterclockwise (CCW) direction. During a steering cycle (either fast or slow speed), the triceps brachii, sternal part of the pectoralis major (PS), and posterior deltoid play major roles in generating steering torque in the CW direction of the CSM. In contrast, the PS, clavicular part of the pectoralis major (PC), and anterior deltoid (AD) largely contribute to torque generation during the CCW CSM. During the swing phase of CSM, AD, PC, and PS are the major muscles that move the hand for the next grasping of the steering wheel in all four conditions. Using the mean activation profiles of the major contributing muscles, the functional roles of these elbow and shoulder muscles were analyzed and are discussed herein. These findings help us to further understand the activation patterns of UE muscles and the kinematic and kinetic changes during two rotating directions and two speeds of CSM, and suggest important implications for future practice in clinical training.