Movement Initiation Research Articles

Effect of friction on levelling of the maxillary canine with NiTi superelastic wire - an in silico experiment using a finite element method

ABSTRACT Purpose To clarify the effect of friction on the levelling process using a NiTi superelastic wire, the levelling process was simulated using a finite element method. Materials and methods The maxillary right canine, which was intruded by 2 mm, was levelled using a 0.014 inch or 0.016 inch NiTi round wire. The wire was supported by two fixed brackets with 0.018 × 0.025 inch slots. The canine, alveolar bone, and bracket were rigid bodies, while the periodontal ligament (PDL) was a nonlinear elastic material. Kinetic friction was caused by contact forces acting on the wire and the bracket slot. Additionally, when the wire was securely ligated to the bracket slot, a constant frictional force caused by the ligation was directly applied to the wire. As the levelling force was applied to the canine, it moved by accumulating the initial tooth movement caused by elastic deformation of the PDL. Results In the case without friction caused by ligation, although the kinetic friction decreased the levelling force during the early levelling stage, the progress of levelling remained unchanged. In the case with friction caused by ligation, as the ligation friction increased, the levelling force decreased, reducing the levelling speed. Furthermore, the levelling process was impeded when the friction caused by ligation reached a critical value. Conclusion When using passive self-ligating brackets, the friction is caused only by levelling forces, which have almost no effect. When the wire is ligated securely to the bracket, additional friction is generated, hindering the levelling process.

Tracing ALS Degeneration: Insights from Spinal Cord and Cortex Transcriptomes.

Amyotrophic Lateral Sclerosis is a progressive neurodegenerative disorder characterized by the loss of upper and lower motor neurons. Key factors contributing to neuronal death include mitochondrial energy damage, oxidative stress, and excitotoxicity. The frontal cortex is crucial for action initiation, planning, and voluntary movements whereas the spinal cord facilitates communication with the brain, walking, and reflexes. By investigating transcriptome data from the frontal cortex and spinal cord, we aim to elucidate common pathological mechanisms and pathways involved in ALS for understanding the disease progression and identifying potential therapeutic targets. In this study, we quantified gene and transcript expression patterns, predicted variants, and assessed their functional effects using computational tools. It also includes predicting variant-associated regulatory effects, constructing functional interaction networks, and performing a gene enrichment analysis. We found novel genes for the upregulation of immune response, and the downregulation of metabolic-related and defective degradation processes in both the spinal cord and frontal cortex. Additionally, we observed the dysregulation of histone regulation and blood pressure-related genes specifically in the frontal cortex. These results highlight the distinct and shared molecular disruptions in ALS, emphasizing the critical roles of immune response and metabolic dysfunction in neuronal degeneration. Targeting these pathways may provide new therapeutic avenues to combat neurodegeneration and preserve neuronal health.

A high-effective swarm intelligence-based multi-robot cooperation method for target searching in unknown hazardous environments

To solve target searching problems for multi-robot cooperation with inaccurate target distance perception in unknown hazardous environments, a hybrid adaptive robotic particle swarm optimizer (RPSO) and grey wolf optimizer (GWO) based algorithm with continuous virtual target guidance is proposed for high effective path planning in the searching. In the initial searching stages, both the wolf behavior-generated position and the gbest position and the pbesti positions from RPSO are employed to guide the motions of robots. With the information provided by these initial robot movement paths, a geometric model is established to generate potential targets. The K-means cluster algorithm is introduced to estimate a virtual target position online from potential targets, with new robot-presenting route information to update the history path information. Then the virtual position is employed as one of the direction components to help the robots approach the actual target. In addition, to avoid mobile robots falling into local convergence, a heuristic moving direction determination scheme is utilized to make robots circumvent obstacles in swarm motions, as well as a mutual repulsion algorithm to keep them in a scattering state. Simulation experiments on different types of unknown environments with varied robot numbers and adaptability testing for a dynamic target are carried out to verify the feasibility of the proposed target searching method with comparisons to the other three famous target searching algorithms. It is verified from the results that the presented method can not only contribute a 100% success rate in all runs of searching for a stochastic dynamic target under a limited maximal velocity, but also produce both the shortest path length and minimum iterations in terms of statistical metrics over the comparative methods.

Sensitivity of Cerebellar Reaching Ataxia to Kinematic and Dynamic Demands.

Individuals with cerebellar ataxia often face significant challenges in controlling reaching, especially when multijoint movements are involved. This study investigated the effects of kinematic and dynamic demands on reaching movements by individuals with cerebellar ataxia and healthy controls using a virtual reality task. Participants reached to target locations designed to elicit a range of coordination strategies between shoulder and elbow joint movements. Results showed that the cerebellar group exhibited greater trajectory curvature and variability in hand paths compared to controls, with pronounced deficits in the initial hand movement direction. Kinematic simulations indicated that early hand movement errors were sensitive to the required onset times and rates of joint movements and were most impaired when opposite direction joint movements were required (e.g., elbow extension with shoulder flexion). This highlights significant disruptions in motion planning and feedforward control in the cerebellar group. Dynamic analysis showed that cerebellar participants' movements were more impaired in reaching directions where interaction torques normally assist the desired elbow and shoulder movements, which required them to rely more on muscle torques to move. These reach directions were also those that required opposite direction joint movements. Overall, our data suggest that reaching deficits in cerebellar ataxia result from 1) the early-phase motion planning deficits that worsen with tight timing requirements and 2) the inability to compensate for interaction torques, particularly when they assist the intended movement.

Experimental analysis of the R290 variable geometry ejector with a spindle

The aim of this work was to experimentally analyze the variable geometry gas ejector with a spindle designed for operation with the natural working fluid propane (R290). The performance of the ejector was evaluated based on the mass entrainment ratio and critical temperature, being the most crucial parameters for optimizing the cooling capacity in ejector refrigeration systems, as well as the ejector efficiency using common literature notation. Additionally, local pressure drop measurements allowed for the determination of pressure profiles inside for different spindle positions used for capacity regulation. The experimentally defined ejector efficiency curves demonstrated the ability to control the ejector capacity by means of the spindle, irrespective of the unfavorable operating conditions. By decreasing the effective throat area using spindle, the ejector mass entertainment ratio increased by 35%. Spindle movement allowed for the decrease of the motive nozzle flow rate by up to 65%, while still maintaining the suction of the secondary flow of the ejector. Moreover, the behavior of a slight increase in suction nozzle flow with a decrease in motive nozzle flow has been observed for the initial movement of the spindle followed by a huge drop for further reduction of the effective throat area, confirming the previous conclusions shown in the literature.

Initial Characteristics of Submillimeter Metal Particles in GIS under Impact Vibration

As a critical component within power systems, Gas Insulated Switchgear (GIS) is notably susceptible to insulation degradation due to submillimeter metal particles, compromising its operational safety and stability. Moreover, impact vibrations induced by circuit breaker operations can dislodge particles that typically adhere to the interior walls, causing them to become airborne and thereby intensifying their movement and discharge activities. To investigate this phenomenon, this study establishes a testing platform where alternating current (AC) voltage is superimposed with impact vibration. A camera system, interfaced with an upper computer, is used to capture the real-time motion behavior of the particles. This study focuses on characterizing the initial movement of submillimeter metal particles of varying sizes under the influence of impact vibration by analyzing critical voltages, such as the initial lift-off voltage, stable jumping voltage, and extinction voltage. Furthermore, the effects of introducing large, centimeter-scale spherical metal and rubber particles on these initial characteristics are examined. The findings provide crucial insights into the initial behavior of submillimeter metal particles in GIS, particularly in relation to circuit breaker operations.

Evidence of gill migration in monogenean polyopisthocotylean Microcotyle sebastis larvae infesting Korean rockfish (Sebastes schlegelii)

In contrast to the well-documented motility of monopisthocotyleans within the monogenean group, the mobility of polyopisthocotyleans, such as Microcotyle sebastis, has largely been undocumented with empirical evidence. This study aimed to investigate the locomotion of the polyopisthocotylean parasite of M. sebastis, which infests Korean rockfish (Sebastes schlegelii), thereby providing tangible evidence of early behavior in polyopisthocotyleans. The oncomiracidium of M. sebastis demonstrated movement facilitated by the hamulus and bilateral cilia, aiding in directional changes and propulsion. In the gill filaments of M. sebastis larvae utilized both the hamulus and their entire body for initial movements, effectively navigating between gill filaments. The hamulus played a crucial role in the locomotion of the early larval stages before the development of three clamp pairs, after which it began to degenerate. This study presents concrete evidence of early mobility in polyopisthocotyleans like M. sebastis, offering insights that could inform aquaculture management strategies, particularly in the mitigation of parasite-induced damages.

Human Initiative Movement: Enhancing Environmental Literacy and Awareness among Orphans in Bengkulu City

This paper examines the Human Initiative organization in Indonesia and its efforts to provide education for orphans in Bengkulu City. It analyzes the organization's resource mobilization using various data collection techniques. Establishing an education center called the Home of Learning is seen as a social movement that successfully achieved its goals. The research considers five aspects proposed by Oberscall: social movement organization, leaders and leadership, resources and resource mobilization, networks and participation, and community opportunities and capacity. The research findings show that (Home of Learning) HOME in Bengkulu is a social movement that effectively implements quality education programs. This success is due to a clear institutional structure, effective leadership, resource mobilization, community participation, and opportunities for child development. Overall, this research highlights the effectiveness of the Human Initiative in providing education for orphaned children.

In-situ electron channeling contrast imaging of local deformation behavior of lath martensite in low-carbon-steel

In-situ tensile Electron Channeling Contrast Imaging (ECCI) observations were performed on low-carbon steel lath martensite to elucidate its plastic deformation mechanisms under tensile loading. Two key deformation processes were identified through the direct observation of dislocation activity: intra-lath crystallographic slip and boundary sliding. The initial dislocation movement signifies the onset of microscopic yielding in lath martensite. As the applied stress increases, macroscopic yielding occurs when dislocations overcome internal barriers like high-dislocation-density walls within the laths. Out-of-lath-plane slip systems exhibit a strong interaction with the lath boundary, hindering their activity after initial small plastic deformation. In contrast, in-lath-plane slip systems predominantly contribute to plastic deformation. After the work hardening triggered by these slip systems, boundary sliding takes over the plastic deformation. The boundary sliding was found to accompany a rapid movement of the dislocation network adjacent to the boundary.

Rainfall and water level fluctuations dominated the landslide deformation at Baihetan Reservoir, China

Understanding the deformation patterns of different types of landslides around reservoirs is crucial for precise prevention and control of related hazards. However, under the complex coupling effect of extreme rainfall and reservoir level fluctuations, the response between various types of landslides and triggering factors is still unclear. Our study employed the Multi-Temporal Interferometric Synthetic Aperture Radar (MT-InSAR) method and wavelet analysis to undertake an early identification and quantitative analysis of deformation patterns of unstable slopes in the Baihetan Reservoir region, China, and explored the responses of different types of landslide deformation to rainfall and reservoir water level fluctuations. The findings reveal distinct differences in the deformation characteristics of unstable slopes around the reservoir. The quantitative analysis of normalized displacement indicated that the convergent-type landslide exhibits an initial rapid movement that gradually tends to be stable, following an exponential function. The steady-type landslide moves at a consistent speed along a linear trendline. The exponential-type landslide starts slowly and then progressively accelerates. The periodic-type landslide displays periodic fluctuations in displacement, which conforms to the Fourier periodic function. Furthermore, comparisons with antecedent rainfall and reservoir water levels reveal that the convergent-type landslide is significantly influenced by water level fluctuations, and both steady-type and exponential-type landslides are subject to the dual impact of rainfall and water level fluctuations, while the periodic-type landslide exhibits a notable response to rainfall. Therefore, this research aims to provide a scientific basis for the prevention and mitigation of geohazards in reservoir areas.

Mental Health Evacuation Rate in USCENTCOM.

Mental health diagnosis requiring further treatment is one of the top reasons for medical evacuation in the U.S. Central Command (USCENTCOM) area of responsibility (AOR) as of 2022. This study establishes a baseline in which the effectiveness of medical interventions can be measured to determine if they have an impact on the rate of evacuation out of USCENTCOM. The study period was January 1, 2017 to December 31, 2021. Individual evacuation data including date of initial movement and necessary specialty care requirements originating from the USCENTCOM AOR were acquired via U.S. Transportation Command's Regulating and Command & Control Evacuation System. The base evacuation rate was calculated for each month, and evacuation rates were analyzed for variations. For the entire study period, the mean monthly evacuation rate was 0.44 evacuations per 1,000 people in the AOR (95% CI, 0.41-0.47). There was no statistically significant difference between any monthly evacuation rate (P = .505). There is a statistically significant difference in the mean evacuation rates for calendar years (P = .003). The highest evacuation rate occurred in 2021. The study establishes a benchmark mental health evacuation rate. This rate will be useful for assessing mental health evacuation reduction initiatives in the USCENTCOM AOR.

Acoustic scene complexity affects motion behavior during speech perception in audio-visual multi-talker virtual environments

In real-world listening situations, individuals typically utilize head and eye movements to receive and enhance sensory information while exploring acoustic scenes. However, the specific patterns of such movements have not yet been fully characterized. Here, we studied how movement behavior is influenced by scene complexity, varied in terms of reverberation and the number of concurrent talkers. Thirteen normal-hearing participants engaged in a speech comprehension and localization task, requiring them to indicate the spatial location of a spoken story in the presence of other stories in virtual audio-visual scenes. We observed delayed initial head movements when more simultaneous talkers were present in the scene. Both reverberation and a higher number of talkers extended the search period, increased the number of fixated source locations, and resulted in more gaze jumps. The period preceding the participants’ responses was prolonged when more concurrent talkers were present, and listeners continued to move their eyes in the proximity of the target talker. In scenes with more reverberation, the final head position when making the decision was farther away from the target. These findings demonstrate that the complexity of the acoustic scene influences listener behavior during speech comprehension and localization in audio-visual scenes.

Different fluorescent labels report distinct components of spHCN channel voltage sensor movement.

We used voltage clamp fluorometry to probe the movement of the S4 helix in the voltage-sensing domain of the sea urchin HCN channel (spHCN) expressed in Xenopus oocytes. We obtained markedly different fluorescence responses with either ALEXA-488 or MTS-TAMRA covalently linked to N-terminal Cys332 of the S4 helix. With hyperpolarizing steps, ALEXA-488 fluorescence increased rapidly, consistent with it reporting the initial inward movement of S4, as previously described. In contrast, MTS-TAMRA fluorescence increased more slowly and its early phase correlated with that of channel opening. Additionally, a slow fluorescence component that tracked the development of the mode shift, or channel hysteresis, could be resolved with both labels. We quantitated this component as an increased deactivation tail current delay with concomitantly longer activation periods and found it to depend strongly on the presence of K+ ions in the pore. Using collisional quenching experiments and structural predictions, we established that ALEXA-488 was more exposed to solvent than MTS-TAMRA. We propose that components of S4 movement during channel activation can be kinetically resolved using different fluorescent probes to reveal distinct biophysical properties. Our findings underscore the need to apply caution when interpreting voltage clamp fluorometry data and demonstrate the potential utility of different labels to interrogate distinct biophysical properties of voltage-gated membrane proteins.

Trial of Brain–Computer Interface for Continuous Motion Using Electroencephalography and Electromyography

Most BCI systems used in neurorehabilitation detect EEG features indicating motor intent based on machine learning, focusing on repetitive movements, such as limb flexion and extension. These machine learning methods require large datasets and are time consuming, making them unsuitable for same-day rehabilitation training following EEG measurements. Therefore, we propose a BMI system based on fuzzy inference that bypasses the need for specific EEG features, introducing an algorithm that allows patients to progress from measurement to training within a few hours. Additionally, we explored the integration of electromyography (EMG) with conventional EEG-based motor intention estimation to capture continuous movements, which is essential for advanced motor function training, such as skill improvement. In this study, we developed an algorithm that detects the initial movement via EEG and switches to EMG for subsequent movements. This approach ensures real-time responsiveness and effective handling of continuous movements. Herein, we report the results of this study.

Agent-based model predicts that layered structure and 3D movement work synergistically to reduce bacterial load in 3D in vitro models of tuberculosis granuloma.

Tuberculosis (TB) remains a global public health threat. Understanding the dynamics of host-pathogen interactions within TB granulomas will assist in identifying what leads to the successful elimination of infection. In vitro TB models provide a controllable environment to study these granuloma dynamics. Previously we developed a biomimetic 3D spheroid granuloma model that controls bacteria better than a traditional monolayer culture counterpart. We used agent-based simulations to predict the mechanistic reason for this difference. Our calibrated simulations were able to predict heterogeneous bacterial dynamics that are consistent with experimental data. In one group of simulations, spheroids are found to have higher macrophage activation than their traditional counterparts, leading to better bacterial control. This higher macrophage activation in the spheroids was not due to higher counts of activated T cells, instead fewer activated T cells were able to activate more macrophages due to the proximity of these cells to each other within the spheroid. In a second group of simulations, spheroids again have more macrophage activation but also more T cell activation, specifically CD8+ T cells. This higher level of CD8+ T cell activation is predicted to be due to the proximity of these cells to the cells that activate them. Multiple mechanisms of control were predicted. Simulations removing individual mechanisms show that one group of simulations has a CD4+ T cell dominant response, while the other has a mixed/CD8+ T cell dominant response. Lastly, we demonstrated that in spheroids the initial structure and movement rules work synergistically to reduce bacterial load. These findings provide valuable insights into how the structural complexity of in vitro models impacts immune responses. Moreover, our study has implications for engineering more physiologically relevant in vitro models and advancing our understanding of TB pathogenesis and potential therapeutic interventions.

Initial and corrective submovement encoding differences within primary motor cortex during precision reaching.

Precision reaching often requires corrective submovements to obtain the desired goal. Most studies of reaching have focused on single initial movements, and implied the cortical encoding model was the same for all submovements. However, corrective submovements may show different encoding patterns from the initial submovement with distinct patterns of activation across the population. Two rhesus macaques performed a precision center-out-task with small targets. Neural activity from single units in the primary motor cortex and associated behavioral data were recorded to evaluate movement characteristics. Neural population data and individual neuronal firing rates identified with a peak finding algorithm to identify peaks in hand speed were examined for encoding differences between initial and corrective submovements. Individual neurons were fitted with a regression model that included the reach vector, position, and speed to predict firing rate. For both initial and corrective submovements, the largest effect remained movement direction. We observed a large subset changed their preferred direction greater than 45° between initial and corrective submovements. Neuronal depth of modulation also showed considerable variation when adjusted for movement speed. By using principal component analysis, neural trajectories of initial and corrective submovements progressed through different neural subspaces. These findings all suggest that different neural encoding patterns exist for initial and corrective submovements within the cortex. We hypothesize that this variation in how neurons change to encode small, corrective submovements might allow for a larger portion of the neural space being used to encode a greater range of movements with varying amplitudes and levels of precision.NEW & NOTEWORTHY Neuronal recordings matched with kinematic behavior were collected in a precision center-out task that often required corrective movements. We reveal large differences in preferred direction and depth of modulation between initial and corrective submovements across the neural population. We then present a model of the neural population describing how these shifts in tuning create different subspaces for signaling initial and corrective movements likely to improve motor precision.

Quantifying inconsistencies in the Hamburg Sign Language Notation System

The advent of machine learning (ML) has significantly advanced the recognition and translation of sign languages, bridging communication gaps for hearing-impaired communities. At the heart of these technologies is data labeling, crucial for training ML algorithms on a huge amount of consistently labeled data to achieve models that generalize well. The adoption of language-agnostic annotations is essential to connect different sign languages, as single-language databases often provide limited lexicon examples, insufficient for training robust ML algorithms. This study critically examines the Hamburg Sign Language Notation System (HamNoSys), which describes the signer’s initial position and body movements, in contrary to the meanings of glosses. Despite HamNoSys’s utility in standardizing transcriptions across various sign languages, our investigation uncovers inconsistencies within HamNoSys that may negatively impact the development of accurate and reliable ML models. By analyzing HamNoSys labels across five sign languages, we identified a lack of standardized annotation procedures and the complexities within HamNoSys that introduce biases and errors. Our findings underscore the urgent need for unified, standardized data annotation guidelines to enhance the accuracy and efficiency of sign language recognition technologies. This research highlights the importance of addressing annotation challenges and advocates for a comprehensive, diversified database to improve the generalization of ML models.

Humans flexibly use visual priors to optimize their haptic exploratory behavior

Humans can use prior information to optimize their haptic exploratory behavior. Here, we investigated the usage of visual priors, which mechanisms enable their usage, and how the usage is affected by information quality. Participants explored different grating textures and discriminated their spatial frequency. Visual priors on texture orientation were given each trial, with qualities randomly varying from high to no informational value. Adjustments of initial exploratory movement direction orthogonal to the textures’ orientation served as an indicator of prior usage. Participants indeed used visual priors; the more so the higher the priors’ quality (Experiment 1). Higher task demands did not increase the direct usage of visual priors (Experiment 2), but possibly fostered the establishment of adjustment behavior. In Experiment 3, we decreased the proportion of high-quality priors presented during the session, hereby reducing the contingency between high-quality priors and haptic information. In consequence, even priors of high quality ceased to evoke movement adjustments. We conclude that the establishment of adjustment behavior results from a rather implicit contingency learning. Overall, it became evident that humans can autonomously learn to use rather abstract visual priors to optimize haptic exploration, with the learning process and direct usage substantially depending on the priors’ quality.

Association Between Gestational Weeks, Initial Maternal Perception of Fetal Movement, and Individual Interoceptive Differences in Pregnant Women: Cross-Sectional Study.

Interoception encompasses the conscious awareness of homeostasis in the body. Given that fetal movement awareness is a component of interoception in pregnant women, the timing of initial detection of fetal movement may indicate individual differences in interoceptive sensitivity. The aim of this study is to determine whether the association between the gestational week of initial movement awareness and interoception can be a convenient evaluation index for interoception in pregnant women. A cross-sectional study was conducted among 32 pregnant women aged 20 years or older at 22-29 weeks of gestation with stable hemodynamics in the Obstetric Outpatient Department. Interoception was assessed using the heartbeat-counting task, with gestational weeks at the first awareness of fetal movement recorded via a questionnaire. Spearman rank correlation was used to compare the gestational weeks at the first awareness of fetal movement and heartbeat-counting task scores. A significant negative correlation was found between the gestational weeks at the first fetal movement awareness and heartbeat-counting task performance among all participants (r=-0.43, P=.01) and among primiparous women (r=-0.53, P=.03) but not among multiparous women. Individual differences in interoception appear to correlate with the differences observed in the timing of the first awareness of fetal movement.

Impact of Social Movements on Renewable Energy Policy in Indonesia: Study of Solar Power Plants

Anthropogenic-induced warming has altered the climate of the Earth, causing significant impacts on urban areas such as compromised water supplies and detrimental health effects. This paper employs a case study approach to analyse the causal relationship between energy consumption and social activities. Such an approach is well-suited to unraveling complex cause-and-effect relationships or pathways. System mapping is a method used in case study research to analyse cause-and-effect relationships in complex systems, such as energy systems. The primary literature was searched utilising the reverse snowball technique, with a focus on renewable energy, particularly solar power. Its importance is highlighted in global efforts to reduce dependence on fossil fuels and mitigate the effects of climate change. Indonesia has extensive solar potential and is preparing to utilise solar energy as a clean power source. Nonetheless, effective policy implementation necessitates more than governmental intention; active participation from social movements is required. Two prominent movements - the Solar Electricity Initiative Movement and the Million Solar Roof National Movement - are significant driving forces in this pursuit. The Role of Social Movements in Environmental Policy Transition to Renewable Energy Sources. Social Movements are instrumental in promoting renewable energy policies through public awareness campaigns, advocacy, and concrete actions. They are essential in accelerating policy changes and facilitating a transition towards clean energy. In light of the challenges posed by climate change, the hard work of social movements has become increasingly significant in achieving Indonesia's goal of becoming a sustainable country that does not rely on fossil fuels.