Elbow Angle Research Articles

Influence of Elbow Angle on Erosion-Corrosion of 1018 Steel for Gas–Liquid–Solid Three Phase Flow

Erosive wear due to the fact of sand severely affects hydrocarbon production industries and, consequently, various sectors of the mineral processing industry. In this study, the effect of the elbow geometrical configuration on the erosive wear of carbon steel for silt–water–air flow conditions were investigated using material loss analysis, surface roughness analysis, and microscopic imaging technique. Experiments were performed under the plug flow conditions in a closed flow loop at standard atmospheric pressure. Water and air plug flow and the disperse phase was silt (silica sand) with a 2.5 wt % concentration, and a silt grain size of 70 µm was used for performing the tests. The experimental analysis showed that silt impact increases material disintegration up to 1.8 times with a change in the elbow configuration from 60° to 90° in plug flow conditions. The primary erosive wear mechanisms of the internal elbow surface were sliding, cutting, and pit propagation. The maximum silt particle impaction was located at the outer curvature in the 50° position in 60° elbows and the 80° position in 90° elbows in plug flow. The erosion rate decreased from 10.23 to 5.67 mm/year with a change in the elbow angle from 90° to 60°. Moreover, the microhardness on the Vickers scale increased from 168 to 199 in the 90° elbow and from 168 to 184 in the 60° elbow.

Comparative Study on the Joint Biomechanics of Different Skill Level Practitioners in Chen-Style Tai Chi Punching.

Purpose: “Yan Shou Hong Cui” is a representative punch in Chen-style Tai Chi. The training is an important factor in affecting the effect of Tai Chi practice. Joint angles are the most intuitive way to evaluate motion. The purpose of this study is to compare the movements of Tai Chi masters and beginners’ movements through the analysis of joint angle and punching effect, and explore the influence of training years on the power generation of Tai Chi punches. Methods: There were 14 Chinese Chen-style Tai Chi subjects recruited for this study. They were divided into the master group (n = 7, age of 38.14 ± 10.42 years, height of 1.68 ± 0.06 m, weight of 71.33 ± 8.61 kg) and the beginner group (n = 7, age of 38.00 ± 11.94 years, height of 1.69 ± 0.07 m, weight of 70.14 ± 9.79 kg). The typical movement from Chen-style Tai Chi is called Yan Shou Hong Cui. All subjects were asked to perform the action three times, and the way of force was applied each time. The kinematic and kinetic characteristics of Tai Chi were analyzed by the VICON 3D motion analysis system (100 Hz) with 16 MX13 cameras, and the punch efficiency was measured by the Chinese Kung Fu Dummy (80,000 Hz). Results: The experimental results show that the shoulder, elbow, and hand movements of the master group are more precise and the force strength is more vigorous (master group: the peak angular velocity of the shoulder joint was −324.12 ± 50.88°/s, the angular velocity of the elbow joint was −112.83 ± 56.98°/s, and the hand angular velocity was −121.69 ± 49.55°/s; beginner group: shoulder angle velocity was −281.17 ± 30.56°/s, the elbow angle speed was −263.64 ± 68.63°/s, and the hand angle speed was −36.80 ± 12.53°/s). The rotation angle and rotation speed of the hip joint in the master group were significantly higher than those in the beginner group (as for the hip rotation angle, the master group was 64°, which was significantly higher than the beginner group’s 44°, and there was a significant difference (p = 0.019 < 0.05)). In terms of rotation speed, the peak value of the master group was 370.3 ± 94.8°/s, which was significantly faster than that of the beginner group at 210.4 ± 56.1°/s, and there was a very significant difference (p = 0.003 < 0.01). The master group’s punch effect acceleration (496.39 ± 256.52 m/s2) was significantly higher than that of the beginner group (396.90 ± 116.79 m/s2). Conclusion: People who practice Tai Chi for a long time differ from the beginners in terms of joint flexibility, punching posture, and the effect of application.

Flame propagation of premixed hydrogen-air explosions in bend pipes

To effectively examine the influence of elbow structures on hydrogen explosion characteristics, this paper conducts a numerical study of flame propagation during hydrogen explosions in bend pipes with different elbow angles. When the elbow angle is large, the flow field movement caused by the pressure difference can separate the “tongue” flame from the outer wall (concave wall), forming a cavity area. The influence of the elbow structure on flame propagation is mainly concentrated in the middle and later stages. In the middle stage, the elbow structure creates a relatively closed space in advance so that the speed peak-2 occurs earlier than it does in the straight pipe. When the elbow angle is α = 90°, the speed peak-2 is the largest at 245.8 m/s. In the later stage, the acceleration effect produced by the outer wall (concave wall) plays a leading role, and the flame accelerates for the third time after passing through the elbow. When the elbow angle is α = 120°, the best acceleration effect is obtained when the flame passes through the elbow. There is an interactive relationship between the development of explosion overpressure and flame propagation in bend pipes. In the middle stage, the interaction between the compression wave, reflected wave and shear wave causes the overpressure to rise in an oscillatory manner. The elbow structures shorten the reflection distance of the pressure wave, and the oscillation frequency and growth range of the explosion overpressure can be much higher than those in a straight pipe.

Effect of elbow angle and weight-bearing on the evaluation of joint congruence in dogs.

Joint congruence is relevant for the assessment of elbow dysplasia, a development disorder in dogs. However, quantification of its variation with joint angle and weight-bearing, important factors in quadrupedal locomotion, is lacking. Our objective was to estimate those effects on the alignment of humeroradioulnar joint surfaces. The usual protocol for screening elbow dysplasia, including mediolateral extended and flexed elbow views, was preceded by a weight-bearing lateromedial standing radiographic view, without sedation. Minimum distances were measured at established points of the humeroradioulnar joints classified with a Grade 0 dysplasia. Sixty elbows (30 Portuguese Pointer dogs) were studied. The joint space between the anconeal process and the ulnar trochlear notch increased with flexion, decreasing with weight-bearing (p< .001). The distance between the humeral trochlea and the trochlear notch at the widest point increased with weight-bearing, while it decreased with flexion. Step and distance between the radial head and the base of the medial coronoid process increased with flexion and decreased with weight-bearing. At this point, physiological changes occurred at the humeroulnar joint space. The methodology allowed to quantify the variations on joint spaces with the elbow angle and weight-bearing, important for the interpretation of congruence in diagnosis and treatment of dysplasia. Reference absolute and indexed values obtained allow future comparisons with other breeds and dysplastic dogs. Physiological variations denoted that radioulnar joint became more incongruent under flexion, and more congruent under weight-bearing, while humeroulnar joint became more congruent under flexion, and more incongruent under weight-bearing.

Training Strategy and sEMG Sensor Positioning for Finger Force Estimation at Various Elbow Angles

Training Strategy and sEMG Sensor Positioning for Finger Force Estimation at Various Elbow Angles

Revisiting the Anconeus using Functional Ultrasound Imaging

IntroductionThe anconeus is a small triangular muscle originating on the posterior aspect of the lateral epicondyle of the humerus with a broad insertion along the postero‐lateral proximal ulna. Cadaveric studies have assessed its potential involvement as an elbow joint stabilizer, whereas electromyographic (EMG) studies have focused on its contribution to elbow extension. However, changes in fascicle length (Lf) and pennation angle (Pa) during voluntary contractions have not been assessed to help elucidate its function. Clinically, the anconeus has been sacrificed for use in various muscle flap transplant and reconstructive surgeries, but the impact of this loss on elbow joint function has not been resolved. Thus, the purpose of this study was to assess the relative architectural changes during in vivo elbow extension and flexion contractions to better understand its functional role.MethodsIn six healthy participants to date (2 females and 4 males) aged 22‐30 years, ultrasound imaging was used to assess Lf and Pa changes in the anconeus. Participants were seated in a Humac Norm dynamometer with their shoulders abducted to 90 degrees and the elbow joint aligned to the axis of rotation. The anconeus was imaged at four different elbow joint angles (35, 90, 135, and 180°) at rest, and during ramp (~5s) isometric maximal voluntary contractions (MVC) of both elbow extension and flexion. Participants also performed maximal‐torque isokinetic (20 degrees/s) extension and flexion contractions through the same 145° range of motion (35 to 180°). For both isometric and isokinetic contractions, Lf and Pa were measured from the ultrasound images using ImageJ software at the same four elbow angles.ResultsAt the four elbow angles (35, 90, 135 and 180°) at rest Lf was 2.92 ± 0.32 cm, 2.77 ± 0.25 cm, 2.52 ± 0.16 cm, 2.29 ± 0.31 cm, whereas Pa was 10.66 ± 2.49°, 12.19 ± 1.98°, 13.88 ± 1.68°, and 16.26 ± 2.13°, respectively. During isometric extension MVCs, Lf decreased by ~10%, 23%, 22%, 10%, whereas Pa increased by ~50%, 59%, 78%, and 46%, at each respective elbow angle. Changes in these parameters made during the isokinetic (dynamic) contractions matched those taken during the isometric contractions at the same four joint angles. During isometric and dynamic isokinetic maximal elbow joint flexion, there were negligible changes in both architectural parameters at the four joint angles.ConclusionDuring elbow extension actions there was a significant decrease in Lf and a significant increase in Pa at all joint angles, however no changes occurred during elbow flexion. The largest change of both parameters was at 90 and 135°, suggesting this is the optimal position for anconeus function. Lack of changes during elbow flexion indicates a minimal functional role during this task which may relate to the anconeus having less importance for overall elbow joint stability. These results highlight the significant architectural changes of the anconeus muscle and illustrate its presumed functional importance during elbow extension. Future studies using in vivo EMG recordings would be useful to further understand its role in elbow joint actions that may have clinical implications.

Numerical simulation of particle erosion in the vertical-upward-horizontal elbow under multiphase bubble flow

Pipe erosion is one of the main reasons for oil leakage and safety accidents in many engineering fields. The purpose of this study is to investigate the impact of gas volume fraction, elbow angle and rib installation position on pipe erosion under multiphase bubble flow. The computational fluid dynamics (CFD) simulation approach based on volume of fluid (VOF) model and discrete phase model (DPM) was adopted to analyze the effect of gas-liquid distribution and particle movement on pipe erosion under different gas volume fractions. A good agreement of pipe erosion distribution was observed between the simulation results and measurement values. Furthermore, the CFD simulation results show that the pipe erosion rate increases rapidly as the gas volume fraction increases. The erosion rate also increases as the elbow angle increases from 15° to 90°. The rib at small installation position angles can protect the pipe from the direct impact of particles.

Comparison of Motion Analysis Systems in Tracking Upper Body Movement of Myoelectric Bypass Prosthesis Users.

Current literature lacks a comparative analysis of different motion capture systems for tracking upper limb (UL) movement as individuals perform standard tasks. To better understand the performance of various motion capture systems in quantifying UL movement in the prosthesis user population, this study compares joint angles derived from three systems that vary in cost and motion capture mechanisms: a marker-based system (Vicon), an inertial measurement unit system (Xsens), and a markerless system (Kinect). Ten healthy participants (5F/5M; 29.6 ± 7.1 years) were trained with a TouchBionic i-Limb Ultra myoelectric terminal device mounted on a bypass prosthetic device. Participants were simultaneously recorded with all systems as they performed standardized tasks. Root mean square error and bias values for degrees of freedom in the right elbow, shoulder, neck, and torso were calculated. The IMU system yielded more accurate kinematics for shoulder, neck, and torso angles while the markerless system performed better for the elbow angles. By evaluating the ability of each system to capture kinematic changes of simulated upper limb prosthesis users during a variety of standardized tasks, this study provides insight into the advantages and limitations of using different motion capture technologies for upper limb functional assessment.

Physical Education Teaching Strategy under Internet of Things Data Computing Intelligence Analysis.

Racket sports such as tennis are amongst the most popular recreational sports activities. Optimizing tennis teaching methods and improving teaching modes can effectively improve the teaching quality of tennis. In this study, a video and image action recognition system based on image processing techniques and Internet of things is developed to overcome the shortcomings of the traditional tennis teaching methods. To validate its performance, the students of tennis courses are divided into experimental group and control group, respectively. The control group is taught by using the traditional tennis teaching method whereas the experimental group is taught by using the IoT video and image recognition teaching system. Three factors of students including service throwing height, arm elbow angle, and knee bending angles of both groups are measured and compared with those of world elite tennis players. The results show that the students' serving abilities in the experimental group are significantly improved using the video and image recognition system based on IoT, and they are better than those of the students in the control group. The proposed video and image processing technique can be applied in students' physical education and can be employed to provide the basis for the innovation of tennis teaching strategies in physical education.

Structural Characterization of the Full-Length Anti-CD20 Antibody Rituximab.

Rituximab, a murine–human chimera, is the first monoclonal antibody (mAb) developed as a therapeutic agent to target CD20 protein. Its Fab domain and its interaction with CD20 have been extensively studied and high-resolution atomic models obtained by X-ray diffraction or cryo-electron microscopy are available. However, the structure of the full-length antibody is still missing as the inherent protein flexibility hampers the formation of well-diffracting crystals and the reconstruction of 3D microscope images. The global structure of rituximab from its dilute solution is here elucidated by small-angle X-ray scattering (SAXS). The limited data resolution achievable by this technique has been compensated by intensive computational modelling that led to develop a new and effective procedure to characterize the average mAb conformation as well as that of the single domains. SAXS data indicated that rituximab adopts an asymmetric average conformation in solution, with a radius of gyration and a maximum linear dimension of 52 Å and 197 Å, respectively. The asymmetry is mainly due to an uneven arrangement of the two Fab units with respect to the central stem (the Fc domain) and reflects in a different conformation of the individual units. As a result, the Fab elbow angle, which is a crucial determinant for antigen recognition and binding, was found to be larger (169°) in the more distant Fab unit than that in the less distant one (143°). The whole flexibility of the antibody has been found to strongly depend on the relative inter-domain orientations, with one of the Fab arms playing a major role. The average structure and the amount of flexibility has been studied in the presence of different buffers and additives, and monitored at increasing temperature, up to the complete unfolding of the antibody. Overall, the structural characterization of rituximab can help in designing next-generation anti-CD20 antibodies and finding more efficient routes for rituximab production at industrial level.

Optimum Design of a Novel Bio-Inspired Bat Robot

Inspired by the agility, high efficiency, and low noise of bat flight, we propose the design of an unoccupied aerial vehicle (UAV) that can mimic the flight behaviors of bats. By adjusting the wing flapping and morphing during both upstroke and downstroke phases, bats achieve aerodynamic performance that generates sufficient lift and thrust forces for diverse maneuvers. To mimic bat morphology in a robot, we use a multi-objective optimization method to determine the Cartesian positions of the wings, and the elbow angle, which in turn influences the wing area. Our goal is to minimize the differences between the biological bat’s limb trajectories (elbow angles and Cartesian trajectories) and those of the robot. Due to the complex dimensionality of bats, a mathematical tool: Principal Component Analysis, is combined with the weighted sum method in the optimization algorithm. Via simulation, we observed overall agreement of elbow angles between the kinematics of a biological bat (Pteropodidae: <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Cynopterus brachyotis</i> ) and the robot, along with a reasonable match on the folding and flapping angles. The proposed method provides a straightforward and robust approach for the optimization of bat-inspired robots.

Size-dependent dynamical analysis of spinning nanotubes conveying magnetic nanoflow considering surface and environmental effects

In this article, a nonlocal strain gradient theory (NSGT) incorporating the thickness effect is developed for dynamics and stability analysis of Y-shaped nanoscale tubes containing magnetic flow with spin motion in magneto-hygro-thermal environments. A detailed study is also conducted to elucidate the impacts of various parameters, such as magnetic flow, scale parameters, fluid velocity, spin speed, downstream elbow angle, localized masses, attached springs, surface effects, and complex environments on the system vibration. The scale-dependent dynamical equations are obtained using Hamilton's principle. The Galerkin scheme is applied to solve the eigenvalue problem of the system. Stability diagrams and vibrational frequencies are obtained. Furthermore, the divergence threshold of the structure is acquired analytically. The outcomes showed that the destructive effects of moisture and nonlocality on the system stability could be alleviated by the stabilizing effects of the magnetic field, strain gradient parameter, and surface effect. Furthermore, it is found that in low- and high-temperature conditions, the temperature variation has an opposite impact on the system stability. The results can be served as a comprehensive benchmark for optimum design of advanced doubly gyroscopic nanoscale systems transporting nanoflow.

Using Bayesian inference to estimate plausible muscle forces in musculoskeletal models

BackgroundMusculoskeletal modeling is currently a preferred method for estimating the muscle forces that underlie observed movements. However, these estimates are sensitive to a variety of assumptions and uncertainties, which creates difficulty when trying to interpret the muscle forces from musculoskeletal simulations. Here, we describe an approach that uses Bayesian inference to identify plausible ranges of muscle forces for a simple motion while representing uncertainty in the measurement of the motion and the objective function used to solve the muscle redundancy problem.MethodsWe generated a reference elbow flexion–extension motion and computed a set of reference forces that would produce the motion while minimizing muscle excitations cubed via OpenSim Moco. We then used a Markov Chain Monte Carlo (MCMC) algorithm to sample from a posterior probability distribution of muscle excitations that would result in the reference elbow motion. We constructed a prior over the excitation parameters which down-weighted regions of the parameter space with greater muscle excitations. We used muscle excitations to find the corresponding kinematics using OpenSim, where the error in position and velocity trajectories (likelihood function) was combined with the sum of the cubed muscle excitations integrated over time (prior function) to compute the posterior probability density.ResultsWe evaluated the muscle forces that resulted from the set of excitations that were visited in the MCMC chain (seven parallel chains, 500,000 iterations per chain). The estimated muscle forces compared favorably with the reference forces generated with OpenSim Moco, while the elbow angle and velocity from MCMC matched closely with the reference (average RMSE for elbow angle = 2°; and angular velocity = 32°/s). However, our rank plot analyses and potential scale reduction statistics, which we used to evaluate convergence of the algorithm, indicated that the chains did not fully mix.ConclusionsWhile the results from this process are a promising step towards characterizing uncertainty in muscle force estimation, the computational time required to search the solution space with, and the lack of MCMC convergence indicates that further developments in MCMC algorithms are necessary for this process to become feasible for larger-scale models.

Capturing Upper Body Kinematics and Localization with Low-Cost Sensors for Rehabilitation Applications.

For upper extremity rehabilitation, quantitative measurements of a person’s capabilities during activities of daily living could provide useful information for therapists, including in telemedicine scenarios. Specifically, measurements of a person’s upper body kinematics could give information about which arm motions or movement features are in need of additional therapy, and their location within the home could give context to these motions. To that end, we present a new algorithm for identifying a person’s location in a region of interest based on a Bluetooth received signal strength (RSS) and present an experimental evaluation of this and a different Bluetooth RSS-based localization algorithm via fingerprinting. We further present algorithms for and experimental results of inferring the complete upper body kinematics based on three standalone inertial measurement unit (IMU) sensors mounted on the wrists and pelvis. Our experimental results for localization find the target location with a mean square error of 1.78 m. Our kinematics reconstruction algorithms gave lower errors with the pelvis sensor mounted on the person’s back and with individual calibrations for each test. With three standalone IMUs, the mean angular error for all of the upper body segment orientations was close to 21 degrees, and the estimated elbow and shoulder angles had mean errors of less than 4 degrees.

Stress and Pressure Pulsation Analysis of Low Temperature Compressor Piping System in LNG Vaporizing Station

LNG (Liquefied Natural Gas) vaporizing stations are usually built in the cities and towns, and the BOG (Boiled Off Gas) pressurizing system is a very important element. In the pressurizing system, the severe vibration of the low-temperature reciprocating compressor may lead to a failure of the pipeline system and the equipment. Therefore, this paper analyzes the stress and pressure pulsation of the BOG compressor piping system in the LNG vaporizing station. The beam model was used to establish the pipe model. The static, harmonic and modal analysis were carried out based on the plane-wave theory and the pressure-fluctuation theory, and the influence factors of support spacing, the settlement of the fulcrum foundation, pipe pressure and elbow angle were analyzed. The main conclusions are as follows: (1) the unbalanced excited force caused by pressure pulsation greatly affects the stress of the exhaust pipe and compressor outlet pipe, and has less influence on the stress of the suction pipe and compressor inlet pipe; (2) although unbalanced excited force is generated in the elbow, it also has an impact on the straight pipe stress; (3) adding an expansion joint to the pipe of the BOG compressor can effectively reduce the stress of the pipe its the displacement, and can increase the flexibility of the pipe.

Shoulder Angle During Ball Release Are Predictors of Ball Velocity Among Medium Pace Bowlers

The purpose of the study. The aim was to find the effect of kinematic variables on ball velocity of medium pace bowlers. Materials and methods. A total of 10 male cricket players who were right arm medium pace bowlers were selected for this study. The kinematic variables selected in this study were wrist angle, elbow angle, shoulder angle, hip angle, knee angle, ankle angle, and centre of gravity. Results. A regression equation with R2 value of 0.616 was obtained from the study, i.e., 52.266+0.371 × (right shoulder angle). Conclusions. The study suggests shoulder angle to be important factor in determining ball velocity among medium pace bowlers

Noninvasive Assessment of In Vivo Passive Skeletal Muscle Mechanics as a Composite Material Using Biomedical Ultrasound.

This study develops a biomedical ultrasound imaging method to infer microstructural information (i.e., tissue level) from imaging mechanical behavior of skeletal muscle (i.e., organ level). We first reviewed the constitutive model of skeletal muscle by regarding it as a transversely isotropic (TI) hyperelastic composite material, for which a theoretical formula was established among shear wave speed, deformation, and material parameters (MPs) using the acoustoelasticity theory. The formula was evaluated by finite element (FE) simulations and experimentally examined using ultrasound shear wave imaging (SWI) and strain imaging (SI) on in vivo passive biceps brachii muscles of two healthy volunteers. The imaging sequence included 1) generation of SW in multiple propagation directions while resting the muscle at an elbow angle of 90°; 2) generation of SW propagating along the myofiber direction during continuous uniaxial muscle extension by passively changing the elbow angle from 90° to 120°. Ultrasound-quantified SW speeds and muscle deformations were fitted by the theoretical formula to estimate MPs of in vivo passive muscle. Estimated myofiber stiffness, stiffness ratio of myofiber to extracellular matrix (ECM), and ECM volume ratio all agreed with literature findings. The proposed mathematical formula together with our in-house ultrasound imaging method enabled assessment of microstructural material properties of in vivo passive skeletal muscle from organ-level mechanical behavior in an entirely noninvasive way. Noninvasive assessment of both micro and macro properties of in vivo skeletal muscle will advance our understanding of complex muscle dynamics and facilitate treatment and rehabilitation planning.

Three-Dimensional Biomechanics of the Trunk and Upper Extremity During Overhead Throwing in Wheelchair Lacrosse Athletes With Spinal Cord Injury.

Quantify differences in overhead throwing kinematics between wheelchair lacrosse athletes with spinal cord injury and able-bodied lacrosse athletes. This is a cross-sectional, prospective study. Motion analysis captured overhead throwing motions of five wheelchair lacrosse athletes with spinal cord injury and six able-bodied lacrosse athletes seated in a wheelchair and standing. Three-dimensional thorax and dominant arm sternoclavicular, acromioclavicular, glenohumeral, elbow, and wrist joint angles, ranges of motion, as well as angular velocities were computed using an inverse kinematics model. Nonparametric tests assessed group differences ( P < 0.05). Participants with spinal cord injury exhibited less peak thorax axial rotation, ranges of motion, and angular velocity, as well as greater wrist flexion than able-bodied participants seated. Participants with spinal cord injury exhibited less peak thorax axial rotation and lateral bending, ranges of motion, and three-dimensional angular velocities; less peak two-dimensional sternoclavicular joint motion, ranges of motion, and peak angular velocities; less peak acromioclavicular joint protraction angular velocity; less glenohumeral joint adduction-abduction and internal-external rotation motion, ranges of motion, and angular velocities; and greater wrist flexion than able-bodied participants standing. Kinematic differences were observed between groups, with athletes with spinal cord injury exhibiting less thorax and upper extremity joint motion and slower joint angular velocities than able-bodied athletes. This knowledge may provide insights for movement patterns and potential injury risk in wheelchair lacrosse.

Accuracy and reliability of tridimensional electromagnetic sensor system for elbow ROM measurement

BackgroundWhile the precise measurement of the range of motion (ROM) of the elbow joint is important for clinical assessment and rehabilitation, problems include low accuracy and reproducibility in goniometer measurements due to the influence of soft tissue. The purpose of this study was to validate elbow joint motion analysis using a three-dimensional electromagnetic sensor system (EMS).MethodsThe accuracy and reproducibility of the EMS system were evaluated at four angles (0°, 45°, 90°, and 135°) using a model bone of the humerus and forearm. In addition, the maximum extension and maximum flexion of six elbows of six healthy volunteers were assessed by radiographic and EMS measurements. Accuracy was assessed by calculating the mean value of the measurement angle, standard deviation, Pearson’s correlation coefficient, and the Bland–Altman method. Reproducibility was assessed by calculating the intra-rater and inter-rater reliabilities using intraclass correlation coefficients.ResultsIn the model bone evaluation, the mean angles of the EMS measurement were 1.2° ± 2.0°, 45.4° ± 2.1°, 91.7° ± 2.4°, and 134.6° ± 2.7° at 0°, 45°, 90°, and 135°, respectively. In the in vivo evaluation, the elbow angles at the maximum extension with the EMS and radiographic angles were 4.7° ± 3.0° and 2.7° ± 2.0°, respectively, and the angles at maximum flexion were 131.8° ± 13.0° and 130.8° ± 4.5°, respectively. There were statistically significant correlations between the EMS and radiographic measurements; the Bland–Altman plots indicated that the two methods were almost in agreement for both extension and flexion.ConclusionsThis method of measuring ROM of the elbow joint using EMS showed high accuracy, reliability, and reproducibility. The current results demonstrated the possibility of using the electromagnetic system to provide an accurate evaluation of the elbow joint in clinical settings.

Structural Basis of Antibody Conformation and Stability Modulation by Framework Somatic Hypermutation.

Accumulation of somatic hypermutation (SHM) is the primary mechanism to enhance the binding affinity of antibodies to antigens in vivo. However, the structural basis of the effects of many SHMs remains elusive. Here, we integrated atomistic molecular dynamics (MD) simulation and data mining to build a high-throughput structural bioinformatics pipeline to study the effects of individual and combination SHMs on antibody conformation, flexibility, stability, and affinity. By applying this pipeline, we characterized a common mechanism of modulation of heavy-light pairing orientation by frequent SHMs at framework positions 39H, 91H, 38L, and 87L through disruption of a conserved hydrogen-bond network. Q39LH alone and in combination with light chain framework 4 (FWR4L) insertions further modulated the elbow angle between variable and constant domains of many antibodies, resulting in improved binding affinity for a subset of anti-HIV-1 antibodies. Q39LH also alleviated aggregation induced by FWR4L insertion, suggesting remote epistasis between these SHMs. Altogether, this study provides tools and insights for understanding antibody affinity maturation and for engineering functionally improved antibodies.