Forward Movement Research Articles

RADIOLOGICAL ASSESSMENT OF SPONDYLOLISTHESIS OF LUMBOSACRAL SPINE

Introduction: One major injury or frequent minor injuries cause the vertebral body, pedicle and superior articular surfaces to slide forward. This disorder is known as spondylolisthesis and is usually accompanied by symptoms, often proportional to the degree of forward movement. Patients may complain of pain in the lower back that spreads to the thighs, and limited range of motion is possible Objectives: The aim of this study is to determine the frequency of spondylolisthesis by age and gender in the patients studied at SKB Mostar. Research methodology: The method of content analysis was used to retrospectively examine X-ray, CT and MRI examinations of patients with the clinical features of lumbar pain syndrome in the period from 1 January 2019 to 1 January 2020 in patients who underwent radiological examination of the LS spine at the Clinical Institute of Radiology of the University Clinical Hospital Mostar. Data were collected from IMPAX at the SKB Mostar Department of Radiology. The input parameters that were observed were: pain syndrome, diagnosis. The output parameters were the radiological findings from the X-ray, CT, and MRI scans. Results: During the study period, 297 spinal scans were performed, and spondylolisthesis was found in 32 patients, or 11%. The youngest respondent was 8 years old, and the oldest was 85 years old. The average age of the respondents was 64.37 years. The largest number of respondents was in the age group of over 75 years old. Of the tests performed, the most common were CT scans, followed by MRI, and the rarest were X-ray scans. The highest prevalence of spondylolisthesis was found in vertebrae L4-L5 and L5-S1 at 41%. Spondylolisthesis was found bilaterally in 9% of cases at the L3-L4 and L5 vertebrae. Conclusion: Most often, spondylolisthesis is found in L4-L5 and L5-S1 vertebrae. There was no difference according to gender, and most often subjects older than 75 years had spondylolisthesis.

Hierarchical behavior control by a single class of interneurons

Animal behavior is organized into nested temporal patterns that span multiple timescales. This behavior hierarchy is believed to arise from a hierarchical neural architecture: Neurons near the top of the hierarchy are involved in planning, selecting, initiating, and maintaining motor programs, whereas those near the bottom of the hierarchy act in concert to produce fine spatiotemporal motor activity. In Caenorhabditis elegans, behavior on a long timescale emerges from ordered and flexible transitions between different behavioral states, such as forward, reversal, and turn. On a short timescale, different parts of the animal body coordinate fast rhythmic bending sequences to produce directional movements. Here, we show that Sublateral Anterior A (SAA), a class of interneurons that enable cross-communication between dorsal and ventral head motor neurons, play a dual role in shaping behavioral dynamics on different timescales. On a short timescale, SAA regulate and stabilize rhythmic bending activity during forward movements. On a long timescale, the same neurons suppress spontaneous reversals and facilitate reversal termination by inhibiting Ring Interneuron M (RIM), an integrating neuron that helps maintain a behavioral state. These results suggest that feedback from a lower-level cell assembly to a higher-level command center is essential for bridging behavioral dynamics at different levels.

Plasma from type 1 diabetes patients promotes pro-atherogenic cholesterol transport in human macrophages.

Hyperglycemia, one of the major risk factors for atherosclerosis, leads to the accumulation of advanced glycation end products (AGEs), contributing to cardiovascular complications. Such accumulation may accelerate the progression of vascular disease in patients with diabetes. Reverse cholesterol transport (RCT) protein, ATP-binding membrane cassette transporters A1 and G1 (ABCA1 and ABCG1) and cholesterol 27-hydroxylase facilitate cholesterol removal from macrophages. AGE inhibits RCT by reducing the expression of ABCA1 and ABCG1. This study aimed to evaluate whether plasma from poorly controlled adolescents with type 1 diabetes (T1D) disrupts cholesterol homeostasis in human monocytes/macrophages. Twenty healthy controls (HCs) and 20 patients with type 1 diabetes mellitus (T1DM), 10-19 years old, were enrolled. Naïve THP-1 macrophages were exposed to plasma from each HC and patient with T1D. Following incubation, mRNA for cholesterol efflux (ABCA1, ABCG1, and 27-hydroxylase) and cholesterol uptake (CD36, ScR-A1, lectin oxidized low-density lipoprotein (LOX)-1, and CXCL16) were isolated. Foam cell formation was quantified to confirm the pro-atherogenic effects of T1D plasma on macrophages. Results showed that T1D plasma had an elevated level of N-(carboxymethyl)-lysine-modified proteins and upregulated CXCL16 and, to a lesser degree, ScR-A1. This change in gene expression in the presence of T1D plasma is associated with increased lipid accumulation and foam cell formation by THP-1 macrophages. In our study, these cells' uptake of an AGE product occurred mainly through the SR-A1 and CXCL16 receptors, leading to increased intracellular oxidized low-density lipoprotein. We conclude that AGEs may contribute to accelerated atherosclerosis in diabetes through effects on both forward and reverse cholesterol movement.

The Forward Movement: Amplifying Black Voices on Race and Orthopaedics-Sports Medicine is Community Medicine.

The Forward Movement: Amplifying Black Voices on Race and Orthopaedics-Sports Medicine is Community Medicine.

Biomechanical factors influencing mental health in college students and the role of physical activity in cognitive resilience

The Mental Health (MH) of college students is increasingly becoming a public health concern, with rising rates of depression, anxiety, and stress. This study aims to explore the relationship between Biomechanical Factors (BF), Physical Activity (PA), and MH outcomes in college students, addressing gaps in current research that frequently overlook the biomechanical features of physical well-being. A cross-sectional observational design was employed, involving 200 college students aged 18–24. SP underwent comprehensive assessments, including postural analysis, movement pattern evaluation, and MH screening. Physical activity levels and cognitive resilience were also measured to evaluate their roles in mediating and moderating the relationships between BF and MH. Key findings revealed that poor biomechanical alignment, such as forward head posture and movement asymmetry, were significantly associated with higher levels of depression, anxiety, and stress. Correlation analysis showed that forward head posture correlated positively with depression (r = 0.52, p < 0.01) and anxiety (r = 0.47, p < 0.01). Movement asymmetry was also associated with MH disturbances (depression: r = 0.45, p < 0.01). PA mediated the relationship between BF and MH, with significant indirect effects via PA for forward head posture (0.18, p < 0.05). Cognitive resilience emerged as a significant moderator, buffering the negative impact of biomechanical inefficiencies on MH outcomes. Within-subject comparisons indicated improvements in BF and MH scores over a one-month follow-up, with decreases in forward head posture (−2.2 ± 1.5 degrees, p < 0.05) and depression scores (−1.5 ± 1.2, p < 0.01).

Automation in Agriculture: A Robotic Approach to Weed Control for Greenhouse Cucumber Cultivation

The increasing global population has heightened the demand for efficient food production, leading to the adoption of compact cultivation methods such as greenhouses. However, weed growth within these controlled environments significantly challenges crop productivity. The application of robots can be a useful and economic choice. This study presents an innovative, purely mechanical system for weed control in greenhouses, specifically designed to operate autonomously on a monorail. The machine stops in the distance between the two main plant rows (cucumber) and its arm goes into the gap to deploy the weeds by rotating its blades. This is continued repeatedly. The cutting is by the rotational speed of the blade. Variable-speed motions of the blade were at 3500, 2500 and 1500 rpm for 3 types of moulinex, triangular, and circular blades. The movement speed of the arm was 10 and 30 rpm and the forward movement speed of the machine was 30, 40, 50, 60, 80 and 120 rpm. The results showed that different blades, blade speeds and engine speed affect significantly (p <0.05) the percentage of weeds being cut. Although the interactions of these factors have no significant effect on percentage; the average percentages by the blades have significant differences. Although the interactions between these factors were not statistically significant, the comparison of means revealed that at lower blade speeds, the blade type had a pronounced effect on weed-cutting efficiency. As blade speed increased, differences in blade performance diminished. The most effective combination was achieved using Moulinex blades at 3500 rpm with a 10-rpm arm speed, resulting in the highest percentage of weeds cut. These findings suggest that optimizing blade type and speed can significantly enhance the mechanical weed control efficiency in greenhouse environments.

Submicrometre spatiotemporal characterization of the Toxoplasma adhesion strategy for gliding motility.

Toxoplasma gondii is a protozoan apicomplexan parasite that uses an adhesion-dependent mode of motility termed gliding to access host cells and disseminate into tissues. Previous studies on Apicomplexa motile morphotypes, including the T. gondii tachyzoite, have identified a cortical actin-myosin motor system that drives the rearward translocation of transmembrane adhesins, thus powering forward movement. However, this model is currently questioned. Here, combining micropatterning and tunable surface chemistry (to edit parasite surface ligands) with flow force and live or super-resolution imaging, we show that tachyzoites build only one apical anchoring contact with the substrate, over which it slides. Furthermore, we show that glycosaminoglycan-parasite interactions are sufficient to promote such force-productive contact and find that the apicobasal flow is set up independent of adhesin release and surface interactions. These findings should enable further characterization of the molecular functions at the T. gondii-substrate mechanosensitive interface and their comparison across apicomplexans.

The role of ball path curvature in basketball shooting accuracy

ABSTRACT During the shooting motion of a basketball, the path of the ball from the beginning of the lift to release follows an S-shaped trajectory. This study is the first to investigate how two distinctive features of the S-shaped ball path, the maximum curvature, κmax, and terminal curvature, σ, are associated with longitudinal accuracy. The sagittal plane ball path and curvature were found using Bezier curves for 31 professional male basketball athletes. Terminal release curvature had a very strong positive correlation to intra-individual release velocity standard deviation (r = 0.73, p < 0.001) indicating that shooters with straighter terminal ball paths had better longitudinal shooting accuracy. It was also observed that κmax coincided with the transition to the forward shooting motion and that players with higher κmax tend to have a clear two-part shooting style rather than a single fluid motion. A comparison between groups of good and poor shooters identified a mean difference in κmax of 7.9 m−1 (p < 0.001, 95% CI: 11.8–4.0 m−1) suggesting that good shooters typically have a higher κmax than poor shooters.

Hierarchical regulation of functionally antagonistic neuropeptides expressed in a single neuron pair

Neuronal communication involves small-molecule transmitters, gap junctions, and neuropeptides. While neurons often express multiple neuropeptides, our understanding of the coordination of their actions and their mutual interactions remains limited. Here, we demonstrate that two neuropeptides, NLP-10 and FLP-1, released from the same interneuron pair, AVKL/R, exert antagonistic effects on locomotion speed in Caenorhabditis elegans. NLP-10 accelerates locomotion by activating the G protein-coupled receptor NPR-35 on premotor interneurons that promote forward movement. Notably, we establish that NLP-10 is crucial for the aversive response to mechanical and noxious light stimuli. Conversely, AVK-derived FLP-1 slows down locomotion by suppressing the secretion of NLP-10 from AVK, through autocrine feedback via activation of its receptor DMSR-7 in AVK neurons. Our findings suggest that peptidergic autocrine motifs, exemplified by the interaction between NLP-10 and FLP-1, might represent a widespread mechanism in nervous systems across species. These mutual functional interactions among peptidergic co-transmitters could fine-tune brain activity.

A compact structure and high-speed actuator designed by imitating the movement of wave

By imitating the natural phenomenon of waves pushing leaves, a compact novel wave-type piezoelectric actuator is proposed in this paper. Compared to traditional inchworm piezoelectric actuators, it combines the clamping unit and driving unit into an arc-shaped flexible driving foot (AFDF). Clamping and driving functions are realized by alternately controlling two ends of the AFDF using two piezoelectric stacks (PESs). One motion unit instead of two makes control simpler, the structure more compact and a faster movement speed. The static model of the AFDF is developed to characterize the mapping laws between structural dimensions and actuator amplification ratios, and the dynamic model represents the relationship between the control signals and move displacements, thus demonstrating the feasibility of the actuator. Finally, a prototype was fabricated, and a testing system was set up to conduct performance evaluations of its motion capabilities. At the driving frequencies of 370 Hz and 380 Hz, the maximum forward and reverse motion speeds can reach 4.345mm/s and 4.537mm/s, respectively. In the range of 0.1-10N, there is no significant change in motion speed, and it has good stability. Its resolution for forward and reverse motion can reach 106nm and 109nm, respectively.

Stalling North Atlantic Tropical Cyclones

Abstract Tropical cyclone (TC) translation speed influences rainfall accumulation, storm surge, and exposure to high winds. These effects are greatest when storms stall. Here, we provide a definition and climatology of slow-moving or stalling TCs in the North Atlantic from 1900 to 2020. A stall is defined as a TC with a track contained in a circular area (“corral”) with a radius of ≤200 km for 72 h. Of the 1274 North Atlantic TCs, 191 storms met this definition (15%). Ten are multistalling storms or those that experienced more than one stall period. Hurricane Ginger in 1971 stalled the most with four separate stalls. Stalling TC locations are clustered in the western Caribbean, the central Gulf Coast, the Bay of Campeche, and near Florida and the Carolinas. Stalling was most common in October TCs (17.3% of October total) and least common in August (8.2%). The estimated annual frequency of stalls significantly increased over the satellite era (1966–2020) by 1.5% yr−1, and the cumulative frequency in the number of stalls compared to all storms also increased. Stalling storms have a significantly higher frequency of major hurricane status than nonstalling storms. Storms are also more likely to stall near the coast (≤200 km). Approximately 40% (n = 77) of the stalling TCs experienced a period of rapid intensification, and five did so within 200 km of a coastal zone. These results will aid emergency managers in regions that experience frequent stalls by providing information they can use to better prepare for the future. Significance Statement The forward movement of a tropical cyclone can influence rainfall, storm surge height, and exposure time to high wind speeds. Storms that slow down or stall can increase total damage by prolonging the exposure time to intense conditions. This study aims to define a stalling storm and then provide a geographic snapshot into our historical experience with these storms. There have been a consistent number of stalling storms over time, with a modest increase starting in the satellite era, likely as a product of increased observational capabilities. Stalls tend to occur in similar places over time and happen more frequently later in the hurricane season (October) when compared to the middle (August). Emergency managers can use this information to identify the likely location and timing for stalls throughout the North Atlantic tropical cyclone season.

Self-Propelled Tubular Micromotors Powered by Hydrogen Bubbles under Mild Conditions: A Major Step toward Biological Applications with Live Cells.

Polymer-based tubular micromotors, featuring an inner layer of Pt nanoparticles (PtNPs), exhibit vigorous propulsion by emitting H2 bubbles in an aqueous ammonia borane (NH3BH3) solution. The hydrolysis of NH3BH3 on the PtNPs facilitates the continuous release of H2 gas from the open-end terminus, driving its forward movement. Unlike conventional O2 bubbles' systems that rely on hydrogen peroxide (H2O2) as fuel, these micromotors can operate in the presence of live cells within the NH3BH3 medium. Consequently, micromotors functionalized with the lectin concanavalin A demonstrate the capability to capture and release Escherichia coli (E. coli) without inducing cell death. Remaining bacteria can be detected by using standard culture techniques. Conversely, micromotors coated with TiO2 nanoparticles enable photosterilization of E. coli without fuel-induced damage. The self-stirring motion of the tubes enhances both bacterial capture and sterilization efficiency. These advancements obviate the necessity for H2O2 as a fuel source, and pave the way for the applications of micromotors in biological contexts.

Forward and backward control of an ultrafast millimeter-scale microrobot via vibration mode transition.

The ability to move backward is crucial for millimeter-scale microrobots to navigate dead-end tunnels that are too narrow to allow for turning maneuvers. In this study, we introduce a 15-mm-long legged microrobot, BHMbot-B, which is capable of rapid forward and backward locomotion through vibration mode transition control. By properly arranging the vibratory motions of the magnet, cantilever, and linkages, the pitching movement of the body and the vibration of the forelegs are in phase during the first-order vibration mode of the cantilever and in antiphase during the second-order mode, which induces the forward and backward movement of the microrobot. Owing to its outstanding load-bearing capacity, the BHMbot-B equipped with dual electromagnetic actuators, an onboard battery, and a control circuit, can execute complex running trajectories under wireless command. Its maximum untethered running speeds are evaluated as 18.0 BL/s (360 mm/s) in the forward direction and 16.9 BL/s (338 mm/s) in the backward direction.

INVESTIGATION OF VERTICAL AND HORIZONTAL DEFORMATIONS OF THE PNEUMATIC SPRING OF A HIGH-SPEED MOVING VEHICLE IN THE LIMITS OF THE ARROW OF THE ARROW GEAR

The object of the research is the pneumatic spring of the second stage of the spring suspension of the high-speed rolling stock of the railway. The vertical and horizontal deformations of the pneumatic spring within the scope of the arrow translation are studied. For constructive reasons, two sections of the turnout were chosen, namely the section of the tip of the spikes and the section of the root of the spikes. In order to determine the deformations of the pneumatic spring, a methodology for its full-scale testing has been developed, which includes the use of a test rig that has a rigid metal frame on which the pneumatic spring and measuring equipment are installed. High-frequency potentiometric linear displacement sensors were used to measure vertical and horizontal deformations. In accordance with the developed complex program of field tests, records of vertical and horizontal deformations of the pneumatic spring of the high-speed rolling stock were obtained during the movement of the turn signal in the forward and opposite directions. It was found that the vertical deformations of the pneumatic spring within the range of movement by the arrow transfer in the furrow and anti-furrow directions are greater than the horizontal ones. In addition, in the opposite direction of movement of the test rig, the vertical deformations of the pneumatic spring are larger compared to the opposite direction of movement. It was established that the maximum values of the vertical deformations of the pneumatic spring are within the range of 3.14–5.05 mm in the wool direction and 4.88–5.95 mm in the anti-wool direction. The maximum values of horizontal deformations are within 1.62–2.94 mm and 1.30–2.53 mm, respectively. It was established that the average value of the vertical and horizontal deformations of the pneumatic spring of the high-speed rolling stock within the range of the arrow of the turnout is: for forward motion – 3.85 mm and 2.02 mm, for forward motion – 5,48 mm and 1.82 mm, respectively. The obtained results will make it possible to proceed to the determination of the dynamic characteristics of the pneumatic spring, and at the stage of designing high-speed rolling stock to study its dynamic indicators and traffic safety indicators under different operating conditions.

The impact of anterior knee displacement on knee joint load during the forward bow step in Tai Chi.

While the forward bow step is a crucial component of Tai Chi (TC) practice, little research has been conducted on its impact on knee joint load and muscle coordination. This study aims to investigate the effects of three different knee forward positions during the TC forward bow step on knee joint loading. Twenty TC practitioners were recruited, and motion capture systems, force platforms, and surface electromyography were utilized to synchronously collect biomechanical parameters of three types of forward bow steps: knee joint not exceeding the tip of the foot (NETT), knee joint forward movement level with the tip of the foot (LTT), and knee joint forward movement exceeding the tip of the foot (ETT). Ligament and muscle forces were calculated using OpenSim software for musculoskeletal modeling and simulation. One-way ANOVA was used to analyze the variations of the indicators during the peak anterior displacement of the knee joint in three movements. Additionally, spm1d one-way ANOVA was employed to examine the variations in the one-dimensional curve of the indicators throughout the entire movement process. Compared with LTT and ETT, the NETT posture was associated with significantly decreased knee flexion angle (F = 27.445, p = 0.001), knee anterior-posterior translation (F = 36.07, p < 0.001), flexion-extension torque (F = 22.232, p = 0.001), ligament force (F = 9.055, p = 0.011). Additionally, there was also a significant reduction in muscle strength, including quadriceps (F = 62.9, p < 0.001), long biceps femoris (F = 18.631, p = 0.002), lateral gastrocnemius (F = 24.933, p = 0.001) and soleus (F = 7.637, p = 0.017). This study further confirms that in the forward lunge movement of Tai Chi, the knee joint load is mainly concentrated during the forward movement phase. Compared to the knee joint load at the NETT position, the load is greater at the LTT position; and compared to the LTT position, the load is even greater at the ETT position.

Retrospective analysis of 62 cases who received clinical application of artificial temporomandibular joint

Objective: To conduct a retrospective study on the treatment outcomes of patients who underwent artificial temporomandibular joint (TMJ) replacement surgery and to evaluate the effectiveness of artificial TMJ treatment. Methods: This study selected 62 patients who received standard Biomet artificial TMJ treatment at Department of Orthognathic and TMJ Surgery, West China Hospital of Stomatology, Sichuan University from May 2010 to September 2023 as the study subjects. Among them, there were 15 male patients and 47 female patients. The average age was 33.5 years old(ranging from 18 to 67 years). This study statistically analyzed postoperative indicators, including maximum mouth opening, forward jaw movement, lateral movement, postoperative pain scores, and patient satisfaction. Results: This study included a total of 62 patients with 99 TMJ joints. No infections occurred postoperatively. The average follow-up period was 33.7 months (ranging from 7 to 170 months). At 6 months postoperatively, the mean mouth opening was (36.1±6.2) mm, lateral movement was (2.1±0.9) mm, and forward jaw movement was (1.0±0.9) mm. The pain visual analog scale score at 6 months postoperatively was (2.8±0.6), and patient satisfaction with the surgery was (8.8±1.1). Spiral CT scans conducted after surgery showed no joint dislocation or migration, and the artificial joint remained stable during the follow-up period. Conclusions: Artificial TMJ replacement is a valuable method for effectively restoring TMJ structure and essential functions related to mouth opening and chewing. It is worthy of promotion as a reconstructive approach for the temporomandibular joint.

A linkage-type self-adaptive deformable tracked mechanism based on the six-bar mechanism

Abstract. In order to design a self-adaptive tracked mechanism that can passively adjust according to the height of different obstacles to improve its obstacle-crossing performance, this paper proposes a linkage-type self-adaptive deformable tracked mechanism. The mechanism based on the planar six-bar mechanism is proposed, and its motion modes and obstacle-crossing capabilities are analyzed. Firstly, based on the characteristics of self-adaptive deformation and the planar six-bar mechanism, a deformable single-degree-of-freedom (DOF) multi-loop mechanism is designed by limiting the DOF and adjusting the link lengths, and subsequently, a linkage-type self-adaptive deformable tracked mechanism module is designed according to the multi-loop mechanism. Secondly, the movement characteristics of the deformable tracked mechanism module are analyzed, and it is obtained that the tracked mechanism has two modes of movement: forward and reverse. These modes include deformable tracked-type obstacle crossing and rocker-arm-type obstacle crossing, respectively. Additionally, it is also obtained that this mechanism is capable of climbing up and descending down slopes. Finally, a prototype model is designed for experimental verification to verify the correctness of the theoretical analysis of the linkage-type self-adaptive deformable tracked mechanism and the feasibility of the obstacle-crossing modes. The results indicate that the linkage-type self-adaptive deformable tracked mechanism is capable of various obstacle-crossing modes, including both forward and reverse movements. These modes encompass the traditional tracked type, the deformable tracked type, and the rocker-arm type, as well as the ability to climb up and descend down slopes. This type of mechanism demonstrates excellent terrain adaptability and is capable of overcoming obstacles, allowing it to traverse some soft and rugged terrain. Consequently, it holds certain application potential.

Nanorobot Swarms Made with Laser-Induced Graphene@Fe3O4 Nanoparticles with Controllable Morphology for Targeted Drug Delivery.

Magnetic nanorobot swarms can mimic group behaviors in nature and can be flexibly controlled by programmable magnetic fields, thereby having great potential in various applications. This paper presents a novel approach for the rapid and large-scale processing of laser-induced graphene (LIG) @Fe3O4-based-nanorobot swarms utilizing one-step UV laser processing technology. The swarm is capable of forming a variety of reversible morphologies under the magnetic field, including vortex-like and strip-like, as well as the interconversion of these, demonstrating high levels of controllability and flexibility. Moreover, the maximum forward motion speed of the nanorobot swarm is up to 2165 μm/s, and the drug loading and release ability of such a nanorobot swarm is enhanced about 50 times due to the presence of graphene, enabling the nanorobot swarm to show rapid and precise targeted drug delivery. Importantly, by controllable morphology transformation to conform to the complicated requirements for the magnetic field, the drug-loaded swarm can smoothly pass through a width-varying zigzag channel while maintaining 96% of the initial drug-loading, demonstrating that LIG @Fe3O4 NPs-based nanorobot swarm can provide effective and controllable targeted drug delivery in complex passages.

Electromyographically controlled prosthetic wrist improves dexterity and reduces compensatory movements without added cognitive load

Wrist function is a top priority for transradial amputees. However, the combined functional, biomechanical, and cognitive impact of using a powered prosthetic wrist is unclear. Here, we quantify task performance, compensatory movements, and cognitive load while three transradial amputees performed a modified Clothespin Relocation Task using two myoelectric prostheses with and without the wrists. The two myoelectric prostheses include a commercial prosthesis with a built-in powered wrist, and a newly developed inexpensive prosthetic wrist for research purposes, called the “Utah wrist”, that can be adapted to work with various sockets and prostheses. For these three participants, task failure rate decreased significantly from 66% ± 12% without the wrist to 39% ± 9% with the Utah wrist. Compensatory forward leaning movements also decreased significantly, from 24.2° ± 2.5 without the wrist to 12.6° ± 1.0 with the Utah wrist, and from 23.6° ± 7.6 to 15.3° ± 7.2 with the commercial prosthesis with an integrated wrist. Compensatory leftward bending movements also significantly decreased, from 20.8° ± 8.6 to 12.3° ± 5.3, for the commercial with an integrated wrist. Importantly, simultaneous myoelectric control of either prosthetic wrist had no significant impact on cognitive load, as assessed by the NASA Task Load Index survey and a secondary detection response task. This work suggests that functional prosthetic wrists can improve dexterity and reduce compensation without significantly increasing cognitive effort. These results, and the introduction of a new inexpensive prosthetic wrist for research purposes, can aid future research and development and guide the prescription of upper-limb prostheses.

On the Control of Directionality of Myosin.

The origin of the unique directionality of myosin has been a problem of fundamental and practical importance. This work establishes in a conclusive way that the directionality is controlled by tuning the barrier for the rate-determining step, namely, the ADP release step. This conclusion is based on exploring the molecular origin behind the reverse directionality of myosins V and VI and the determination of the origin of the change in the barriers of the ADP release for the forward and backward motions. Our investigation is performed by combining different simulation methods such as steer molecular dynamics (SMD), umbrella sampling, renormalization method, and automated path searching method. It is found that in the case of myosin V, the ADP release from the postrigor (trailing head) state overcomes a lower barrier than the prepowerstroke (leading head) state, which is also evident from experimental observation. In the case of myosin VI, we noticed a different trend when compared to myosin V. Since the directionality of myosins V and VI follows a reverse trend, we conclude that such differences in the directionality are controlled by the free energy barrier for the ADP release. Overall, the proof that the directionality of myosin is determined by the activation barrier of the rate-determining step in the cycle, rather than by some unspecified dynamical effects, has general importance.