scholarly journals Pavlovian Control of Intraspinal Microstimulation to Produce Over-Ground Walking

2019 ◽  
Author(s):  
Ashley N Dalrymple ◽  
David A Roszko ◽  
Richard S Sutton ◽  
Vivian K Mushahwar
Keyword(s):  
Learning Strategy ◽  
Control Strategies ◽  
Reaction Force ◽  
The Other ◽  
State Transitions ◽  
Intraspinal Microstimulation ◽  
Cord Injury ◽  
Sensor Signals ◽  
Cat Model ◽  
Over Ground Walking

ABSTRACTObjectiveNeural interface technologies are more commonly used in people with neural injury. To achieve a symbiotic relationship between device and user, the control system of the device must augment remaining function and adapt to day-to-day changes. The goal of this study was to develop predictive control strategies to produce alternating, over-ground walking in a cat model of hemisection spinal cord injury (SCI) using intraspinal microstimulation (ISMS).ApproachEight cats were anaesthetized and placed in a sling over a walkway. The residual function of a hemisection SCI was mimicked by manually moving one hind-limb through the walking cycle over the walkway. ISMS targeted motor networks in the lumbosacral enlargement to activate muscles in the other limb using low levels of current (< 130 µA). Four different people took turns to move the “intact” limb. Two control strategies, which used ground reaction force and angular velocity information about the manually moved limb to control the timing of the transitions of the other limb, were compared. The first strategy, reaction-based control, used thresholds on the sensor values to initiate state transitions. The other strategy used a reinforcement learning strategy, Pavlovian control, to learn predictions about the sensor values. Thresholds on the predictions were used to initiate transitions.Main ResultsBoth control strategies were able to produce alternating, over-ground walking. Reaction-based control required manual tuning of the thresholds for each person to produce walking, whereas Pavlovian control did not. We demonstrate that learning occurs quickly during walking. Predictions of the sensor signals were learned quickly, initiating transitions in no more than 4 steps. Pavlovian control was resilient to transitions between people walking the limb, between cat experiments, and recovered from mistakes during walking.SignificanceThis work demonstrates that Pavlovian control can augment remaining function and allow for personalized walking with minimal tuning requirements.

Intelligent Control of a Spinal Prosthesis to Restore Walking After Neural Injury: Recent Work and Future Possibilities

2020 ◽  
Vol 05 (01n02) ◽  
pp. 2041003 ◽  
Author(s):  
Ashley N. Dalrymple ◽  
Vivian K. Mushahwar
Keyword(s):  
Machine Learning ◽  
Intelligent Control ◽  
Control Strategies ◽  
Machine Learning Algorithms ◽  
Biologically Inspired ◽  
Intraspinal Microstimulation ◽  
Sensorimotor Systems ◽  
Difficult Terrain ◽  
Over Ground Walking

This review focuses on the development of intelligent, intuitive control strategies for restoring walking using an innovative spinal neural prosthesis called intraspinal microstimulation (ISMS). These control strategies are inspired by the control of walking by the nervous system and are aimed at mimicking the natural functionality of locomotor-related sensorimotor systems. The work to date demonstrates how biologically inspired control strategies, some including machine learning methods, can be used to augment remaining function in models of complete and partial paralysis developed in anesthetized cats. This review highlights the advantages of learning predictions to produce automatically adaptive control of over-ground walking. This review also speculates on the possible future applications of similar machine learning algorithms for challenging walking tasks including navigating obstacles and traversing difficult terrain. Finally, this review explores the potential for plasticity and motor recovery with long-term use of such intelligent control systems and neural interfaces.

Using a saddle-assistive device equipped with mechanical orthosis for walking of the person with incomplete spinal cord injury

2021 ◽  
pp. 095441192110201
Author(s):  
Akbar Hojjati Najafabadi ◽  
Saeid Amini ◽  
Farzam Farahmand
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Reaction Force ◽  
Assistive Devices ◽  
Assistive Device ◽  
Walking Ability ◽  
Vertical Force ◽  
Incomplete Spinal Cord Injury ◽  
Combined Application ◽  
Cord Injury

The majority of the people with incomplete spinal cord injury lose their walking ability, due to the weakness of their muscle motors in providing torque. As a result, developing assistive devices to improve their conditionis of great importance. In this study, a combined application of the saddle-assistive device (S-AD) and mechanical medial linkage or thosis was evaluated to improve the walking ability in patients with spinal cord injury in the gait laboratory. This mobile assistive device is called the saddle-assistive device equipped with medial linkage or thosis (S-ADEM). In this device, a mechanical orthosis was used in a wheeled walker as previously done in the literature. Initially, for evaluation of the proposed assistive device, the experimental results related to the forces and torques exerted on the feet and upper limbs of a person with the incomplete Spinal Cord Injury (SCI) during walking usingthe standard walker were compared with an those obtained from using the S-ADEM on an able-bodied subject. It was found that using this combination of assistive devices decreases the vertical force and torque on the foot at the time of walking by 53% and 48%, respectively compared to a standard walker. Moreover, the hand-reaction force on the upper limb was negligible instanding and walking positions usingthe introduced device. The findings of this study revealed that the walking ability of the patients with incomplete SCI was improved using the proposed device, which is due to the bodyweight support and the motion technology used in it.

Improving sit-to-stand transition by the saddle-assistive device in the spinal cord injury: A case study

2021 ◽  
pp. 095441192110033
Author(s):  
Akbar Hojjati Najafabadi ◽  
Saeid Amini ◽  
Farzam Farahmand
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Lower Limb ◽  
Reaction Force ◽  
Assistive Device ◽  
Limb Weakness ◽  
Sit To Stand ◽  
Lower Limb Weakness ◽  
Wide Range ◽  
Cord Injury

Physical problems caused by fractures, aging, stroke, and accidents can reduce foot power; these, in the long term, can dwindle the muscles of the waist, thighs, and legs. These conditions provide the basis for the invalidism of the harmed people. In this study, a saddle-walker was designed and evaluated to help people suffering from spinal cord injury and patients with lower limb weakness. This S-AD works based on body weight support against the previously report designs. This saddle-walker consisted of a non-powered four-wheel walker helping to walk and a powered mechanism for the sit-to-stand (STS) transfer. A set of experiments were done on the STS in the use of the standard walker and the saddle-assistive device(S-AD). A comparison of the results showed that this device could reduce the vertical ground reaction force (GRF) of the legs up to 70%. Using this device could help a wide range of patients with lower limb weakness and SCI patients in changing from sitting to standing.

Analysis of the Collaborative Learning Application in Reading Material at Ninth Grade of SMPN 7 Kinali Pasaman Barat

2021 ◽  
Vol 1 (1) ◽  
pp. 71-88
Author(s):  
Sukini Sukini ◽  
Hilma Pami Putri
Keyword(s):  
Qualitative Research ◽  
Collaborative Learning ◽  
Learning Strategy ◽  
Research Question ◽  
Ninth Grade ◽  
The Other ◽  
Reading Material ◽  
Other Hand ◽  
Object Based

This research was designed to find out and analyze of the collaborative learning application in reading material at ninth grade of SMPN 7 Kinali Pasaman Barat. This research conducted due to several problems found in the field which were students make a fuss when working in groups, students do not listen to given the assignment by the teacher. It can be seen that there were students who work on group assignments that care and others were just busy talking with others. This research was done in order to answer the research question “What were the role of student and what were the role of teacher in collaborative learning at the ninth grade of SMPN 7 Kinali Pasaman Barat?” This research was a qualitative research using collaborative learning strategy. The purpose of this research was to find out and analyze the collaborative learning applicationin reading material at the ninth grade of SMPN 7 KinaliPasaman Barat by analyzing the teacher’s and students’ role in the collaborative learning. The researcher used interview and observation as the instrument of the research. The interview was directed to both students and teacher, which for the students contained 12 questions and for the teacher contained 7 questions. The researcher took 2 classes namely IX1 and IX2 as the observation object.                    Based on the finding from interview and observation of the collaborative learning in SMPN 7 Kinali Pasaman Barat, it was found that the teacher already fulfilled her role in the collaborative learning effectively, in the other hand the students still lack of the role as the cheer leader. They still laughed at their friends mistake. Besides that, the other roles that the students supposed to have were already done effectively. As the conclusion, the collaborative learning in SMPN 7 Kinali Pasaman Barat was good since the students and the teacher were doing their role effectively

scholarly journals Subarachnoid Fluid Lactate and Paraplegia after Descending Aorta Aneurysmectomy: Two Compared Case Reports

2013 ◽  
Vol 2013 ◽  
pp. 1-4
Author(s):  
Enrico Giustiniano ◽  
Silvia Eleonora Malossini ◽  
Francesco Pellegrino ◽  
Franco Cancellieri
Keyword(s):  
Cerebrospinal Fluid ◽  
Surgical Procedures ◽  
Case Reports ◽  
Lactate Concentration ◽  
Postoperative Outcome ◽  
The Other ◽  
Thoracoabdominal Aorta ◽  
Descending Aorta ◽  
Helpful Tool ◽  
Cord Injury

We report a comparison of two cases regarding subjects who underwent thoracoabdominal aorta aneurysmectomy. During the procedure we monitored cerebrospinal fluid lactate concentration. One patient experienced postoperative paraplegia and his cerebrospinal fluid lactate concentration was much higher than that in the other case, whose postoperative outcome was uneventful. Consequently we consider that monitoring the lactate concentration in cerebrospinal fluid during thoracic aorta surgical procedures may be a helpful tool to predict the ischemic spine-cord injury allowing for trying to recover it precociously.

Numerical Modelling of a Planing Craft with a V-Shaped Spray Interceptor Arrangement in Calm Water

2020 ◽  
Author(s):  
Mikloš Lakatoš ◽  
Kristjan Tabri ◽  
Abbas Dashtimanesh ◽  
Henrik Andreasson
Keyword(s):  
Reaction Force ◽  
The Other ◽  
Numerical Comparison ◽  
Total Resistance ◽  
Stagnation Line ◽  
Planing Craft ◽  
Water Conditions ◽  
Calm Water ◽  
Wetted Surface Area ◽  
Novel Concept

V-shaped spray interceptors are a novel concept of spray deflection on planing craft. Conventional spray rails are positioned longitudinally on the bottom of the hull and detach the spray from hull deflecting it towards the sides or slightly down and aftward. The V-shaped spray interceptors, on the other hand, are located in the spray area forward of the stagnation line such that they would deflect the oncoming spray down and aftward, thereby producing a reaction force that reduces the total resistance. An experimental study reported that the V-shaped spray interceptors to reduce the total resistance at low planing speed by up to 4%. This paper features a numerical comparison of two planing craft, one equipped with a conventional setup of longitudinal spray rails and the other with a V-shaped spray interceptor. Both configurations were simulated in calm water conditions and were free to pitch and heave in a speed range of Fr∇ = 1.776 to 3.108. The numerical model was analyzed for grid sensitivity and numerical results were compared with experimental results. The two concepts were compared in terms of total resistance, lift, running position and wetted surface area. Conventional spray rails were shown to account for up to 5.6% of total lift and up to 6.5% of total resistance. The V-shaped spray interceptor was shown to reduce the total resistance by up to 8%. Since the V-shaped spray interceptor was located in the spray area forward of the stagnation line, it deflected the oncoming spray thereby producing a horizontal reaction force (-1.5% of RTM) in the direction of the craft’s motion. The rest of differences in the total resistance of the hulls equipped with the conventional spray rails and the V-shaped spray rails was due to absence of the resistance of the absent spray rails.

A novel astrophysics-based framework for prediction of binding affinity of glucose binder

2020 ◽  
Vol 34 (31) ◽  
pp. 2050346
Author(s):  
Rajesh Kondabala ◽  
Vijay Kumar ◽  
Amjad Ali ◽  
Manjit Kaur
Keyword(s):  
Decision Tree ◽  
Binding Affinity ◽  
Cross Validation ◽  
Learning Strategy ◽  
Experimental Results ◽  
The Other ◽  
Computational Time ◽  
Glucose Binding ◽  
Regression Algorithms

In this paper, a novel astrophysics-based prediction framework is developed for estimating the binding affinity of a glucose binder. The proposed framework utilizes the molecule properties for predicting the binding affinity. It also uses the astrophysics-learning strategy that incorporates the concepts of Kepler’s law during the prediction process. The proposed framework is compared with 10 regression algorithms over ZINC dataset. Experimental results reveal that the proposed framework provides 99.30% accuracy of predicting binding affinity. However, decision tree provides the prediction with 97.14% accuracy. Cross-validation results show that the proposed framework provides better accuracy than the other existing models. The developed framework enables researchers to screen glucose binder rapidly. It also reduces computational time for designing small glucose binding molecule.

Moving past sporadic eruptions, discursive killing, and running amok: recognizing the convergence of the serial and spree killer

2019 ◽  
Vol 9 (3) ◽  
pp. 138-146 ◽  
Author(s):  
Enzo Yaksic
Keyword(s):  
Control Strategies ◽  
Gun Control ◽  
The Other ◽  
Management Skills ◽  
Content Type ◽  
Limited Mobility ◽  
Rapid Sequence ◽  
Clear Delineation ◽  
Serial Murderers ◽  
Practical Implications

Purpose Rapid sequence homicide offenders (RSHOs), formerly spree killers, are an understudied population due to the confusion surrounding their classification in relation to serial murderers. The paper aims to discuss this issue. Design/methodology/approach An exploratory, comparative analysis of 56 RSHOs and 60 serial murderers was conducted on US-based data from 2014 to 2018 derived from the Consolidated Serial Homicide Offender Database to determine similarities and differences between the cohorts. Findings RSHOs and serial murderers are similar in that they often kill their victims using a singular method, have limited mobility, kill a similar number of victims both known and unknown to them and are both supremely motivated by domestic anger. There is an inverse relationship between serial murderers and RSHOs: as one group increases in prevalence the other decreases. Practical implications In order to divert men into more pro-social activities, attention must be dedicated to increasing mental health services that provide them with the tools to diffuse their hatred and couple that with effective gun control strategies and ways to enhance the compromised anger management skills of a generation of volatile men. Originality/value Academicians have been hesitant to juxtapose these offenders but based this conclusion on surface-level differences. A reimagining of these categorical structures is needed. The once clear delineation between these cohorts may continue to shrink and synchronize until one subsumes the other.

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